WO2023203805A1 - Ultrasonic wave transducer - Google Patents

Ultrasonic wave transducer Download PDF

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Publication number
WO2023203805A1
WO2023203805A1 PCT/JP2022/042880 JP2022042880W WO2023203805A1 WO 2023203805 A1 WO2023203805 A1 WO 2023203805A1 JP 2022042880 W JP2022042880 W JP 2022042880W WO 2023203805 A1 WO2023203805 A1 WO 2023203805A1
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WO
WIPO (PCT)
Prior art keywords
metal plate
ultrasonic transducer
sub
vibrating
section
Prior art date
Application number
PCT/JP2022/042880
Other languages
French (fr)
Japanese (ja)
Inventor
浩誠 山本
Original Assignee
株式会社村田製作所
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Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Priority to JP2023562236A priority Critical patent/JPWO2023203805A1/ja
Publication of WO2023203805A1 publication Critical patent/WO2023203805A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers

Definitions

  • the present invention relates to an ultrasonic transducer.
  • Patent Document 1 Japanese Patent Application Publication No. 2007-142967
  • the ultrasonic sensor described in Patent Document 1 is attached to the inner surface of a vehicle bumper or a resin portion.
  • the ultrasonic sensor includes an ultrasonic transducer and a housing.
  • the ultrasonic transducer transmits and receives ultrasonic waves.
  • the housing houses the ultrasonic transducer.
  • the ultrasonic transducer is fixed in contact with the inner surface of the bottom surface of the casing, and the outer surface of the bottom surface abuts against the inner surface of the vehicle bumper or the resin portion.
  • An ultrasonic transmission section is formed in a part of the bottom surface of the casing.
  • the ultrasonic transmission section is arranged so as to be in contact with the vehicle bumper or the resin part and the ultrasonic vibrator.
  • the ultrasonic transmission section is made of a material different from the material of the casing, and is made of a material having an acoustic impedance intermediate between the acoustic impedance of the ultrasonic transducer and the acoustic impedance of the vehicle bumper or resin portion.
  • the ultrasonic sensor transmits and receives ultrasonic waves via an ultrasonic transmission section and a vehicle bumper or resin part.
  • Ultrasonic transducers are required to be miniaturized while ensuring a wide directional angular range.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic transducer that can be downsized while ensuring a wide angular range of directivity.
  • the ultrasonic transducer includes an exterior portion, a metal plate portion, a cylinder, an ultrasonic vibrator, and a restraining portion.
  • the exterior part has a mounting surface.
  • the metal plate portion is attached to the mounting surface and extends along the mounting surface.
  • the cylindrical body is attached to the metal plate part.
  • the ultrasonic transducer is attached to the cylindrical body, and faces the metal plate part with an interval therebetween.
  • the restraint part is attached to the metal plate part and sandwiches the cylinder at a constant interval.
  • the main vibrating part which is a part of the exterior part and the metal plate part located inside the cylindrical body when viewed from the first direction perpendicular to the mounting surface, resonates with the ultrasonic transducer in an opposite phase in the first direction. do.
  • the sub-vibration part is a part of the exterior part and the metal plate part located outside the cylinder and inside the restraint part in a second direction orthogonal to the first direction. vibrates resonantly with opposite phases in the first direction.
  • the metal plate When viewed from the first direction, the metal plate extends in a third direction perpendicular to each of the first direction and the second direction of the cylindrical body while penetrating the metal plate at a position that becomes the sub-vibrating part of the metal plate.
  • a slit is formed. Viewed from the first direction, when the outer edge of the cylinder is at the 0% position and the inner edge of the restraint is at the 100% position in the position range in the second direction between the cylinder and the restraint part, The center of the slit is located at a position of 35% or more.
  • the ultrasonic transducer includes an exterior portion, a metal plate portion, a cylinder, an ultrasonic vibrator, and a restraining portion.
  • the exterior part has a mounting surface.
  • the metal plate portion is attached to the mounting surface and extends along the mounting surface.
  • the cylindrical body is attached to the metal plate part.
  • the ultrasonic transducer is attached to the cylindrical body, and faces the metal plate part with an interval therebetween.
  • the restraint part is attached to the metal plate part and sandwiches the cylinder at a constant interval.
  • the main vibrating part which is a part of the exterior part and the metal plate part located inside the cylindrical body when viewed from the first direction perpendicular to the mounting surface, resonates with the ultrasonic transducer in an opposite phase in the first direction. do.
  • the sub-vibration part is a part of the exterior part and the metal plate part located outside the cylinder and inside the restraint part in a second direction orthogonal to the first direction. vibrates resonantly with opposite phases in the first direction.
  • On a second surface of the metal plate portion opposite to the first surface on the exterior side at a position that becomes a sub-vibration portion of the metal plate portion when viewed from the first direction, in each of the first direction and the second direction.
  • a first bottomed groove is formed extending in a third direction orthogonal to the first bottomed groove. Viewed from the first direction, when the outer edge of the cylinder is at the 0% position and the inner edge of the restraint is at the 100% position in the position range in the second direction between the cylinder and the restraint part, The center of the first bottomed groove is disposed at a position of 25% or more and 60% or less or a position of 83% or more.
  • the ultrasonic transducer includes an exterior portion, a metal plate portion, a cylinder, an ultrasonic vibrator, and a restraining portion.
  • the exterior part has a mounting surface.
  • the metal plate portion is attached to the mounting surface and extends along the mounting surface.
  • the cylindrical body is attached to the metal plate part.
  • the ultrasonic transducer is attached to the cylindrical body, and faces the metal plate part with an interval therebetween.
  • the restraint part is attached to the metal plate part and sandwiches the cylinder at a constant interval.
  • the main vibrating part which is a part of the exterior part and the metal plate part located inside the cylindrical body when viewed from the first direction perpendicular to the mounting surface, resonates with the ultrasonic transducer in an opposite phase in the first direction. do.
  • the sub-vibration part is a part of the exterior part and the metal plate part located outside the cylinder and inside the restraint part in a second direction orthogonal to the first direction. vibrates resonantly with opposite phases in the first direction.
  • On the first surface of the metal plate part on the exterior part side at a position that becomes the sub-vibration part of the metal plate part when viewed from the first direction, in a third direction perpendicular to each of the first direction and the second direction.
  • An extending second bottomed groove is formed. Viewed from the first direction, when the outer edge of the cylinder is at the 0% position and the inner edge of the restraint is at the 100% position in the position range in the second direction between the cylinder and the restraint part, The center of the second bottomed groove is located at a position of 16% or more and 76% or less or a position of 94% or more.
  • FIG. 1 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 1 of the present invention.
  • FIG. 1 is an exploded perspective view showing the configuration of an ultrasonic transducer according to Embodiment 1 of the present invention.
  • FIG. 2 is a cross-sectional view showing the configuration of an ultrasonic transducer included in the ultrasonic transducer according to Embodiment 1 of the present invention.
  • FIG. 3 is a plan view of a state in which the restraining portion is resonating in a fundamental mode when viewed from a first direction.
  • FIG. 7 is a plan view of a state in which the restraint section is resonating in a higher order mode when viewed from a first direction.
  • FIG. 2 is a perspective view showing a displacement state simulated and analyzed using the finite element method when the ultrasonic transducer according to Embodiment 1 of the present invention is transmitting or receiving ultrasonic waves.
  • 7 is a cross-sectional view of the ultrasonic transducer of FIG. 6 viewed from the direction of the arrow VII-VII.
  • FIG. 3 is a schematic diagram showing a state in which sub sound sources that vibrate in an opposite phase to the main sound source are arranged on both sides of the main sound source. It is a graph showing the directivity obtained by simulation analysis using the finite element method while changing the distance between the main sound source and the sub sound source into three types: 4 mm, 6 mm, and 8 mm.
  • FIG. 7 is a graph showing the relationship between the position of the center of the slit and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section.
  • 11 is a graph showing directivity obtained by simulation analysis using the finite element method for three cases in which the center of the slit is at the 19% position, the 69% position, or the 94% position, extracted from the data in FIG. 10. It is a graph showing the relationship between the difference obtained by subtracting the resonance frequency of the main vibration section from the resonance frequency of the sub vibration section and the ratio of the resonance amplitude of the sub vibration section to the resonance amplitude of the main vibration section.
  • FIG. 7 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a first modification.
  • 3 is a graph showing the magnitude of noise generated from children.
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a fourth modification of Embodiment 1 of the present invention.
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a fifth modification of Embodiment 1 of the present invention. It is a perspective view showing a metal plate part and a restraint part concerning a 1st example. It is a perspective view which shows the metal plate part and restraint part based on 2nd Example.
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a fourth modification of Embodiment 1 of the present invention.
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a fifth modification of Embodiment 1 of the present invention.
  • It is a perspective view showing a metal plate part and a restraint part concerning a 1st example. It is a perspective view which shows
  • FIG. 7 is a perspective view showing a metal plate part and a restraint part according to a third embodiment. It is a perspective view which shows the metal plate part and restraint part based on 4th Example. It is a graph showing the relationship between the ratio of the extension length of the slit to the length of the ultrasonic transducer and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section.
  • the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part, the stress acting on the sub-vibrating part per unit displacement in the first direction of the ultrasonic vibrator, and the sub-vibrating part It is a graph which shows the relationship between each resonance amplitude of a vibrating part. It is a longitudinal cross-sectional view showing a metal plate part, a cylindrical body, and a restraint part with which an ultrasonic transducer according to a sixth modification of Embodiment 1 of the present invention is provided.
  • FIG. 3 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 2 of the present invention.
  • FIG. 7 is a cross-sectional view showing a state in which an internal space formed by a metal plate part and a restraining part is filled with a damping material in an ultrasonic transducer according to a second embodiment of the present invention.
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 3 of the present invention. It is a graph which shows the relationship between the position of the center of a 2nd bottomed groove, and the ratio of the resonance amplitude of a sub-vibration part to the resonance amplitude of a main vibration part. It is a graph showing directivity analyzed by simulation using the finite element method for four cases in which the center of the second bottomed groove is at the 4% position, 46% position, 82% position, or 96% position. .
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 4 of the present invention.
  • An ultrasonic transducer in which a bottomed groove is not formed in the metal plate part an ultrasonic transducer in which only a first bottomed groove is formed in the metal plate part, and an ultrasonic transducer in which only a second bottomed groove is formed in the metal plate part.
  • FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a modification of Embodiment 4 of the present invention.
  • FIG. 1 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to Embodiment 1 of the present invention.
  • FIG. 2 is an exploded perspective view showing the configuration of the ultrasonic transducer according to Embodiment 1 of the present invention.
  • the ultrasonic transducer 100 according to the first embodiment of the present invention includes an exterior portion 110, a metal plate portion 150, a cylinder 120, an ultrasonic transducer 130, and a restraining portion 140. Equipped with.
  • the exterior part 110 is, for example, a part of the exterior of a vehicle bumper, the casing of a personal computer or a smartphone, furniture, or a wall of a house. Exterior portion 110 has an inner surface 111.
  • the exterior portion 110 has a substantially flat plate shape.
  • the exterior portion 110 is made of resin whose main component is polypropylene or the like.
  • a recess 112 is formed in the inner surface 111 of the exterior part 110.
  • the thickness of the exterior portion 110 is, for example, 3 mm, and the thickness of the portion of the exterior portion 110 where the recessed portion 112 is formed is, for example, 1 mm. Note that the recess 112 does not necessarily have to be formed in the exterior part 110.
  • the first direction perpendicular to the inner surface 111 of the exterior part 110 is the Z-axis direction
  • the second direction perpendicular to the first direction is the X-axis direction
  • the third direction is perpendicular to each of the first and second directions.
  • the direction is shown as the Y-axis direction.
  • the metal plate portion 150 has a flat plate shape.
  • the metal plate portion 150 is attached to the inner surface 111, which is the attachment surface of the exterior portion 110, and extends along the inner surface 111 of the exterior portion 110. In this embodiment, the metal plate portion 150 is attached within the recess 112.
  • the metal plate portion 150 is made of an aluminum alloy such as duralumin containing aluminum, or a metal such as stainless steel.
  • the thickness of the metal plate portion 150 is smaller than the distance between the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction), which will be described later.
  • the thickness of the metal plate portion 150 is, for example, 1 mm.
  • the cylindrical body 120 is attached to the center portion of the metal plate portion 150 when viewed from the first direction (Z-axis direction).
  • one end of the cylindrical body 120 in the first direction (Z-axis direction) is bonded to the metal plate portion 150.
  • the cylinder 120 has a rectangular annular shape.
  • the cylinder 120 has a longitudinal direction along the third direction (Y-axis direction) and a lateral direction along the second direction (X-axis direction).
  • the axial direction of the cylinder 120 is along the first direction (Z-axis direction).
  • the cylinder 120 is made of resin, glass epoxy, metal, or the like. From the viewpoint of suppressing changes in characteristics of the ultrasonic transducer 100 due to temperature changes, the cylindrical body 120 is preferably made of metal. On the other hand, from the viewpoint of lowering the frequency of the ultrasound transmitted or received by the ultrasound transducer 100 and from the viewpoint of downsizing the ultrasound transducer 100, the cylindrical body 120 is preferably made of resin. In this embodiment, the cylindrical body 120 is made of aluminum.
  • FIG. 3 is a cross-sectional view showing the configuration of an ultrasonic transducer included in the ultrasonic transducer according to Embodiment 1 of the present invention.
  • the ultrasonic transducer 130 is attached to the cylindrical body 120, and faces the metal plate portion 150 with an interval therebetween.
  • the ultrasonic transducer 130 is attached to the other end of the cylinder 120 in the first direction (Z-axis direction), and faces the metal plate part 150 with the inner space of the cylinder 120 in between. are doing.
  • the ultrasonic transducer 130 is a piezoelectric element including a piezoelectric body 131.
  • the ultrasonic transducer 130 includes two piezoelectric bodies 131 stacked together.
  • the polarization directions Dp of the two piezoelectric bodies 131 are different from each other.
  • the polarization directions Dp of the two piezoelectric bodies 131 face each other in the first direction (Z-axis direction).
  • the two piezoelectric bodies 131 are sandwiched between a first electrode 132 and a second electrode 133, and an intermediate electrode 134 is arranged between the two piezoelectric bodies 131.
  • the first electrode 132 and the second electrode 133 are electrically connected to the processing circuit 10 to which an alternating current voltage can be applied.
  • the ultrasonic transducer 130 is a so-called series bimorph piezoelectric transducer.
  • the total thickness of the two piezoelectric bodies 131 is, for example, 1.05 mm or more, from the viewpoint of matching the sound speed of the transverse waves of the main vibrating section and the sub-vibrating section, which will be described later, with the sound velocity of the transverse waves of the ultrasonic vibrator 130. It is 95 mm or less.
  • the restraint part 140 is attached to the edge of the metal plate part 250 when viewed from the first direction (Z-axis direction).
  • the restraint part 140 sandwiches the cylinder 120 with a constant interval between the cylinders 120.
  • the restraint part 140 has an annular shape.
  • the restraining portion 140 has a rectangular annular shape.
  • the restraint part 140 surrounds the cylinder 120 from the outside while leaving an interval between the cylinders 120.
  • the restraining portion 140 may sandwich the cylinder 120 at a constant interval in the second direction (X-axis direction).
  • One end of the restraint section 140 in the first direction (Z-axis direction) is bonded to the metal plate section 150.
  • the restraint part 140 is made of metal such as stainless steel or aluminum, or a highly rigid material such as glass epoxy. By restraining the portion of the exterior part 110 to which the restraining part 140 is attached with the metal plate part 150 in between, the vibrations of the sub-vibrating part, which will be described later, can be confined and stabilized within the sub-vibrating part.
  • FIG. 4 is a plan view of a state in which the restraint section resonates in the fundamental mode, viewed from the first direction.
  • FIG. 5 is a plan view of a state in which the restraint section resonates in a higher-order mode, as viewed from the first direction.
  • the resonance frequency of the fundamental mode of the restraint section 140 shown in FIG. 4 is lower than the resonance frequency of the ultrasonic transducer 130 by 20% or more.
  • the high-order mode resonance frequency of the restraint section 140 shown in FIG. 5 is higher than the resonance frequency of the ultrasonic transducer 130 by 20% or more.
  • FIG. 6 is a perspective view showing a displacement state simulated and analyzed using the finite element method when the ultrasonic transducer according to Embodiment 1 of the present invention is transmitting or receiving ultrasonic waves.
  • FIG. 7 is a cross-sectional view of the ultrasonic transducer of FIG. 6 viewed from the direction of the arrow VII-VII.
  • the thickness of the exterior part 110 in the part where the recess 112 is formed is 1 mm
  • the thickness of the metal plate part 150 is 1 mm
  • the thickness of the piezoelectric body 131 is 0.6 mm
  • the longitudinal dimension of the outer shape of the cylinder 120 is The width of the cylinder 120 in the first direction (Z-axis direction) was 0.4 mm
  • the width of the cylinder 120 in the second direction (X-axis direction) was 0.5 mm. That is, the longitudinal dimension of the inner shape of the cylindrical body 120 was 15 mm, and the lateral dimension was 5 mm.
  • the width of the restraint part 140 in the second direction (X-axis direction) was 2 mm, and the thickness of the restraint part 140 in the first direction (Z-axis direction) was 3 mm.
  • the interval between the cylindrical body 120 and the restraint part 140 in the second direction (X-axis direction) was set to 4 mm.
  • the ultrasonic transducer 100 has the inner side of the cylindrical body 120 in the exterior portion 110 and the metal plate portion 150 when viewed from the first direction (Z-axis direction).
  • the main vibration part 110m which is the part located in the second direction (X-axis direction)
  • the sub-vibration part which is the part located outside the cylinder 120 and inside the restraint part 140 in the exterior part 110 and the metal plate part 150 in the second direction (X-axis direction) It has a section 110s.
  • Each of the main vibrating section 110m and the sub-vibrating section 110s includes a thinned portion of the exterior section 110 in which a recess 112 is formed and a metal plate section 150.
  • the main vibrating section 110m resonates in an opposite phase to the ultrasonic vibrator 130 in the first direction (Z-axis direction). That is, the displacement direction of the resonance vibration Bm of the main vibration section 110m and the displacement direction of the resonance vibration Bp of the ultrasonic transducer 130 are opposite to each other in the first direction (Z-axis direction).
  • the sub-vibrating part 110s resonates in a phase opposite to that of the main vibrating part 110m in the first direction (Z-axis direction). That is, the displacement direction of the resonant vibration Bs of the sub-vibrating section 110s and the displacement direction of the resonant vibration Bm of the main vibrating section 110m are opposite to each other in the first direction (Z-axis direction).
  • the main vibrating part 110m resonates in an opposite phase to the ultrasonic transducer 130 in the first direction (Z-axis direction), so that the main vibration in the exterior part 110 as shown in FIG. Vibration leakage to the surroundings of the portion 110m can be reduced.
  • a wide angular range of directivity of the ultrasonic transducer 100 can be ensured.
  • the ultrasonic transducer 100 by exciting the above-mentioned resonant vibration Bs in the sub-vibrating section 110s, the ultrasonic transducer can transmit at least one of high-sound-pressure ultrasonic waves and high-sensitivity ultrasonic wave reception. A wide angular range of 100 degrees of directivity can be secured.
  • the resin such as polypropylene that constitutes the exterior portion 110 is hard at low temperatures and soft at high temperatures, so the Young's modulus changes greatly depending on the temperature. Therefore, the resonance frequency of each of the main vibrating section 110m and the sub-vibrating section 110s changes depending on the temperature.
  • each of the main vibrating section 110m and the sub-vibrating section 110s includes the metal plate section 150 whose Young's modulus changes with temperature less than the exterior section 110. Changes in the resonance frequency of each of the vibrating section 110m and the sub-vibrating section 110s due to temperature can be reduced. As a result, the temperature characteristics of the ultrasonic transducer 100 can be stabilized. Note that the greater the Young's modulus of the material constituting the metal plate portion 150, the thinner the metal plate portion 150 can be.
  • a metal plate made of an aluminum alloy is used for a thickness of 1 mm of the exterior part 110 of the main vibrating part 110m and the sub-vibrating part 110s, which is made of a resin whose main component is polypropylene.
  • the thickness of the portion 150 can be reduced to 1 mm, and the thickness of the metal plate portion 150 made of stainless steel can be reduced to 0.6 mm.
  • the thickness of the exterior part 110 that constitutes each of the main vibrating part 110m and the sub-vibrating part 110s is reduced. Changes in each resonance frequency of 110s due to temperature can be reduced. This also makes it possible to stabilize the temperature characteristics of the ultrasonic transducer 100.
  • the thickness of the exterior portion 110 that constitutes each of the main vibrating portion 110m and the sub vibrating portion 110s is twice or less the thickness of the metal plate portion 150.
  • FIG. 8 is a schematic diagram showing a state in which sub sound sources that vibrate in an opposite phase to the main sound source are arranged on both sides of the main sound source.
  • the distance between the main sound source MS and the sub sound source SS is A simulation analysis was performed using the finite element method with D as a parameter.
  • the sound pressure ratio between the main sound source MS and the sub sound source SS was set to 9:1.
  • the resonance frequency of each of the main sound source MS and sub sound source SS was 54 kHz.
  • FIG. 9 is a graph showing the directivity obtained by simulation analysis using the finite element method while changing the distance between the main sound source and the sub sound source into three types: 4 mm, 6 mm, and 8 mm.
  • the vertical axis shows the sound pressure level (dB)
  • the circumferential axis shows the radiation angle (°) from the center of the main sound source.
  • the solid line represents the directivity when the distance D between the main sound source MS and the sub sound source SS is 4 mm
  • the dotted line represents the directivity when the distance D is 6 mm
  • the absolute value of the radiation angle at which the sound pressure level decreases to -3 dB is 54 degrees when the distance D is 4 mm, 47 degrees when the distance D is 6 mm, and 47 degrees when the distance D is 8 mm. It was 38°. Thus, it was observed that the shorter the distance D between the main sound source MS and the sub sound source SS, the wider the angular range of the directivity of the ultrasonic transducer.
  • the metal plate portion 150 included in the ultrasonic transducer 100 will be described in detail.
  • a metal plate portion is provided at a position of a sub-vibration portion 110s of a metal plate portion 150 when viewed from the first direction (Z-axis direction).
  • a slit 151 is formed that extends in the third direction (Y-axis direction) while penetrating through 150 .
  • the outer edge of the cylinder 120 When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the slit 140 is taken as the 100% position, the center 151c of the slit 151 is arranged at a position of 35% or more.
  • each of the main vibrating section 110m and the sub-vibrating section 110s includes the metal plate section 150, the temperature characteristics of the ultrasonic transducer can be stabilized.
  • the metal plate portion 150 is thick. However, as the metal plate portion 150 becomes thicker, the resonance frequency of each of the main vibrating portion 110m and the sub vibrating portion 110s increases. The angular range of directivity of the ultrasonic transducer becomes narrower.
  • the ultrasonic transducer 100 by forming the slits 151 at desired positions of the metal plate portion 150, the ultrasonic transducer 100 can be is downsized.
  • FIG. 10 is a graph showing the relationship between the position of the center of the slit and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section.
  • the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section
  • the horizontal axis shows the position of the center of the slit.
  • the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section is indicated by a dotted line.
  • the second direction (X) was displaced within the position range (in the axial direction).
  • the outer edge of the cylinder 120 is at the 0% position
  • the inner edge of the restraint part 140 is at the 0% position.
  • the position was set at 100%.
  • the thickness of the metal plate portion 150 is 1 mm, and the length of the vibration region of the sub-vibration portion 110s in the second direction (X-axis direction), that is, the length of the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction).
  • the interval was 4 mm, and the width of the slit 151 in the second direction (X-axis direction) was 0.5 mm.
  • the center 151c of the slit 151 is located at the center of the width of the slit 151 in the second direction (X-axis direction).
  • the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that when the center 151c of the slit 151 is arranged at a position of 34% or less, the slit in the metal plate section is
  • the ratio was the same as or lower than the ratio in the comparative example in which no slit was formed, but when the center 151c of the slit 151 was placed at a position of 35% or more, the comparison in which no slit was formed in the metal plate part
  • the ratio rapidly increased beyond the same ratio as the ratio in the example, and increased until the center 151c of the slit 151 reached the 94% position, that is, the position near the inner edge of the restraint part 140.
  • Figure 11 shows the directivity extracted from the data in Figure 10 and analyzed by simulation using the finite element method for three cases in which the center of the slit is at the 19% position, 69% position, or 94% position. It is a graph.
  • the vertical axis shows the sound pressure level (dB)
  • the circumferential axis shows the radiation angle (°) from the center of the main vibrating section.
  • the solid line indicates the directivity when the center 151c of the slit 151 is at the 19% position
  • the dotted line indicates the directivity when the center 151c of the slit 151 is at the 69% position
  • the directivity when the center 151c of the slit 151 is at the 94% position.
  • FIG. 12 is a graph showing the relationship between the difference obtained by subtracting the resonance frequency of the main vibration section from the resonance frequency of the sub vibration section and the ratio of the resonance amplitude of the sub vibration section to the resonance amplitude of the main vibration section.
  • the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating part to the resonance amplitude of the main vibrating part
  • the horizontal axis shows the difference (%) obtained by subtracting the resonant frequency of the main vibrating part from the resonant frequency of the sub-vibrating part. kHz).
  • the data of the ultrasonic transducer according to the present embodiment in which the center 151c of the slit 151 is at the 94% position is shown as a solid line
  • the data of the ultrasonic transducer according to the comparative example in which no slit is formed in the metal plate portion is shown as a dotted line. ing.
  • the difference obtained by subtracting the resonance frequency of the main vibration section 110m from the resonance frequency of the sub-vibration section 110s is 10 kHz.
  • FIG. 13 is a graph showing the relationship between the distance between the cylinder and the restraint section and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section.
  • the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating part to the resonance amplitude of the main vibrating part
  • the horizontal axis shows the distance (mm) between the cylinder and the restraining part.
  • the data of the ultrasonic transducer according to the present embodiment in which the center 151c of the slit 151 is at the 94% position is shown as a solid line
  • the data of the ultrasonic transducer according to the comparative example in which no slit is formed in the metal plate portion is shown as a dotted line. ing.
  • the interval between the cylinder body 120 and the restraint part 140 in the second direction (X-axis direction) is narrow. Even so, the resonance amplitude of the sub-vibration section 110s was able to be ensured larger than that of the ultrasonic transducer according to the comparative example in which no slits were formed in the metal plate section.
  • the second The interval in the direction can be set to 4 mm in the ultrasonic transducer according to the present embodiment, but must be set to 8 mm or more in the ultrasonic transducer according to the comparative example.
  • the ultrasonic transducer 100 can be made smaller while ensuring a wide angular range of directivity of the ultrasonic transducer 100.
  • the distance between the cylinder body 120 and the restraining part 140 in the second direction (X-axis direction) is shortened.
  • a wide angular range of directivity of the acoustic wave transducer 100 can be ensured.
  • the ultrasonic vibrator 130 is a so-called series bimorph piezoelectric vibrator, but the ultrasonic vibrator 130 may be another type of piezoelectric vibrator.
  • an ultrasonic vibrator of an ultrasonic transducer according to a modification of the first embodiment of the present invention will be described.
  • FIG. 14 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a first modification.
  • the ultrasonic transducer 130a according to the first modification is a piezoelectric element including two piezoelectric bodies 131 stacked together.
  • the polarization directions Dp of the two piezoelectric bodies 131 are equal to each other.
  • the ultrasonic transducer 130a is a so-called parallel bimorph piezoelectric transducer.
  • each of the two piezoelectric bodies 131 is configured to be sandwiched between a first electrode 132 and a second electrode 133 so that an alternating current voltage can be applied thereto.
  • the first electrode 132 is fixed at ground potential.
  • Each of the cylindrical body 120 and the restraint part 140 is made of metal, and the first electrode 132, the cylindrical body 120, the metal plate part 150, and the restraint part 140 are mechanically and electrically connected to each other to provide electromagnetic shielding. It consists of
  • FIG. 15 shows an ultrasonic transducer according to a first modified example and an ultrasonic transducer according to a reference example that differs from the ultrasonic transducer according to the first modified example only in that the restraint part is made of an insulating material.
  • 3 is a graph showing the magnitude of noise generated from an ultrasonic transducer in FIG.
  • the noise level of the ultrasonic transducer according to the reference example was 190 mV
  • the noise level of the ultrasonic transducer according to the first modification example was 165 mV, and the above It was confirmed that noise could be reduced by configuring an electromagnetic shield.
  • FIG. 16 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a second modification.
  • an ultrasonic transducer 130b according to the second modification is a piezoelectric element including four piezoelectric bodies 131 stacked together.
  • the polarization direction Dp of the two piezoelectric bodies 131 located on the outside among the four piezoelectric bodies 131 is directed to one side of the first direction (Z-axis direction), and the polarization direction Dp of the two piezoelectric bodies 131 located on the inside of the four piezoelectric bodies 131 is
  • the polarization direction Dp of the piezoelectric body 131 faces the other side of the first direction (Z-axis direction).
  • the ultrasonic transducer 130b is a so-called multimorph piezoelectric transducer.
  • FIG. 17 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a third modification.
  • an ultrasonic transducer 130c according to the third modification is a piezoelectric element including one piezoelectric body 131. Specifically, the piezoelectric body 131 is sandwiched between a first electrode 132 and a diaphragm 135 made of metal.
  • the ultrasonic transducer 130c is a so-called unimorph piezoelectric transducer.
  • FIG. 18 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to a fourth modification of Embodiment 1 of the present invention.
  • an ultrasonic transducer 100a according to a fourth modification of Embodiment 1 of the present invention includes an exterior portion 110, a cylindrical body 120a, an ultrasonic transducer, a restraining portion 140, and a metal plate portion. 150.
  • the cylinder 120a has a cylindrical shape with a bottom.
  • the cylindrical body 120a is made of metal.
  • a piezoelectric body 131 is attached to the outer bottom surface of the cylindrical body 120a, forming an ultrasonic transducer that is a unimorph piezoelectric transducer.
  • FIG. 19 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to a fifth modification of Embodiment 1 of the present invention.
  • the ultrasonic transducer 100b according to the fifth modification of the first embodiment of the present invention includes an exterior portion 110, a cylinder 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate. 150b.
  • a portion of the slit 151 of the metal plate portion 150b overlaps with the restraining portion 140.
  • a portion of the metal plate portion 150b that is more than half the width of the slit 151 may overlap with the restraining portion 140.
  • FIG. 20 is a perspective view showing a metal plate part and a restraint part according to the first embodiment.
  • FIG. 21 is a perspective view showing a metal plate part and a restraint part according to the second embodiment.
  • FIG. 22 is a perspective view showing a metal plate part and a restraint part according to the third embodiment.
  • FIG. 23 is a perspective view showing a metal plate part and a restraining part according to the fourth embodiment.
  • FIG. 24 is a graph showing the relationship between the ratio of the extension length of the slit to the length of the ultrasonic transducer and the ratio of the resonance amplitude of the sub-vibration section to the resonance amplitude of the main vibration section.
  • the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating part to the resonance amplitude of the main vibrating part
  • the horizontal axis shows the ratio (%) of the extended length of the slit to the length of the ultrasonic transducer. ) is shown.
  • the interval between the cylinder 120 and the restraint part 140 in the second direction (X-axis direction) is 4.5 mm
  • the width of the slit 151 in the second direction (X-axis direction) is 1 mm
  • the center of the slit 151 is 151c was placed at the 89% position.
  • a slit 151 having a length of 4 mm is formed in the center portion in the third direction (Y-axis direction).
  • a slit 151 having a length of 8 mm is formed from the center to both ends in the third direction (Y-axis direction).
  • a slit 151 having a length of 12 mm is formed from the center to both ends in the third direction (Y-axis direction).
  • a slit 151 having a length of 16 mm is formed from the center to both ends in the third direction (Y-axis direction).
  • the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that the ratio of the extended length of the slit 151 to the length of the ultrasonic transducer 130 is 15% or more and 85%. It increased as the size increased within the following range. From this analysis result, by adjusting the ratio of the extension length of the slit 151 to the length of the ultrasonic transducer 130, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m can be set to a desired value. It was confirmed that it can be changed to
  • the relationship between the stress in the first direction (Z-axis direction) that acts and the resonance amplitude of the sub-vibrating section 110s will be explained using a simulation analysis using the finite element method.
  • FIG. 25 shows the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part, and the first direction acting on the sub-vibrating part per unit displacement of the ultrasonic vibrator.
  • 3 is a graph showing the relationship between the stress and the resonance amplitude of the sub-vibration section.
  • the vertical axis on the left is the resonance amplitude ( ⁇ m) of the sub-vibrating part
  • the vertical axis on the right is the stress in the first direction acting on the sub-vibrating part per unit displacement of the ultrasonic transducer (MPa/ ⁇ m)
  • the horizontal axis represents the ratio (%) of the thickness of the metal plate portion to the thickness of the exterior portion of each of the main vibrating portion and the sub vibrating portion.
  • the resonance amplitude of the sub-vibrating section is shown by a solid line
  • the stress in the first direction acting on the sub-vibrating section per unit displacement of the ultrasonic transducer is shown by a dotted line.
  • the exterior part 110 was made of a resin whose main component was polypropylene, the metal plate part 150 was made of an aluminum alloy, and the amplitude of the voltage for driving the ultrasonic transducer 130 was 1V.
  • the thickness of the exterior portion 110 of the portions constituting each of the main vibrating portion 110m and the sub vibrating portion 110s was 1 mm.
  • the unit of the ultrasonic vibrator 130 increases.
  • the stress in the first direction (Z-axis direction) acting on the sub-vibrating section 110s per displacement has increased.
  • the ratio of the thickness of the metal plate part 150 to the thickness of the exterior part 110 of the parts constituting each of the main vibrating part 110m and the sub-vibrating part 110s exceeds 160%, the sub-vibrating part per unit displacement of the ultrasonic vibrator 130 Although the stress in the first direction (Z-axis direction) acting on the sub-vibrating section 110s was increasing, the resonance amplitude of the sub-vibrating section 110s was small.
  • the thickness of the exterior part 110 in the parts that make up each of the main vibrating part 110m and the sub-vibrating part 110s.
  • the ratio of the thickness of the metal plate portion 150 to the thickness of the metal plate portion 150 is 100% or more, the temperature characteristics of the ultrasonic transducer 100 can be stabilized.
  • the exterior portion 110 of the portion constituting each of the main vibration section 110m and the sub-vibration section 110s is preferably 100% or more and 160% or less.
  • the displacement of the sub-vibrating part 110s becomes smaller.
  • the density of stainless steel is approximately three times that of aluminum alloy. Therefore, when the metal plate part 150 is made of stainless steel, the displacement of the sub-vibrating part 110s per unit displacement of the ultrasonic vibrator 130 becomes small.
  • the ratio of the thickness of the metal plate part 150 to the thickness of the exterior part 110 of the parts constituting each of the main vibrating part 110m and the sub-vibrating part 110s is as follows. , preferably 100% or less.
  • the thickness of the exterior part 110 of the parts that make up each of the main vibrating part 110m and the sub-vibrating part 110s When the ratio of the thickness of the metal plate portion 150 to the thickness of the metal plate portion 150 is 60% or more, the temperature characteristics of the ultrasonic transducer 100 can be stabilized.
  • the parts constituting each of the main vibrating section 110m and the sub-vibrating section 110s are
  • the ratio of the thickness of the metal plate portion 150 to the thickness of the exterior portion 110 is preferably 60% or more and 100% or less.
  • FIG. 26 is a longitudinal sectional view showing a metal plate portion, a cylinder body, and a restraining portion included in an ultrasonic transducer according to a sixth modification of Embodiment 1 of the present invention.
  • the metal plate portion 150, the cylindrical body 120, and the restraining portion 140 included in the ultrasonic transducer according to the sixth modification of the first embodiment of the present invention are integrally formed by forging or the like.
  • the restraining portion 140 and the metal plate portion 150 are made of a cylindrical metal member with a bottom, and the cylinder 120 protrudes from the bottom of the metal member.
  • the first vibration section 110s when viewed from the first direction (Z-axis direction), the first vibration section 110s is located at a position of the sub-vibration section 110s of the metal plate section 150 while penetrating the metal plate section 150.
  • a slit 151 extending in three directions (Y-axis direction) is formed.
  • the outer edge of the cylinder 120 When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the slit 140 is taken as the 100% position, the center 151c of the slit 151 is arranged at a position of 35% or more. Thereby, the ultrasonic transducer 100 can be made smaller while ensuring a wide directional angular range of the ultrasonic transducer 100.
  • the restraining portion 140 has an annular shape. This makes it possible to suppress vibration leakage in the third direction (Y-axis direction) orthogonal to the second direction (X-axis direction) in which the angular range of directivity is expanded.
  • the ultrasonic vibrator 130 is a piezoelectric element including a piezoelectric body. This allows the ultrasonic transducer 100 to have a simple configuration.
  • Embodiment 2 of the present invention differs from the ultrasonic transducer according to Embodiment 1 of the present invention in that a bottomed groove is formed in the metal plate portion instead of a through slit.
  • a bottomed groove is formed in the metal plate portion instead of a through slit.
  • FIG. 27 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to Embodiment 2 of the present invention.
  • an ultrasonic transducer 200 according to Embodiment 2 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 250. .
  • a second vibration section 110s is provided at a position of the sub-vibration section 110s of the metal plate section 250 when viewed from the first direction (Z-axis direction).
  • a first bottomed groove 251 extending in three directions (Y-axis direction) is formed.
  • the outer edge of the cylinder 120 When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 251c of the first bottomed groove 251 is located at a position of 25% or more and 60% or less or 83% or more. In this embodiment, the depth of the first bottomed groove 251 is half the thickness of the metal plate portion 250.
  • the relationship between the position of the center 251c of the first bottomed groove 251 formed in the metal plate part 250 and the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is determined using the finite element method. We will explain the results of simulation analysis using this method.
  • FIG. 28 is a graph showing the relationship between the center position of the first bottomed groove and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section.
  • the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section
  • the horizontal axis shows the position of the center of the first bottomed groove.
  • the second direction (X) The center 251c of the first bottomed groove 251 was displaced within the position range (in the axial direction).
  • the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140 in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, the outer edge of the cylinder 120 is at the 0% position, and the inner edge of the restraint part 140 is at the 0% position.
  • the position was set at 100%.
  • the thickness of the metal plate portion 250 is 1 mm, and the length of the vibration region of the sub-vibrating portion 110s in the second direction (X-axis direction), that is, the length of the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction).
  • the interval was 7 mm, and the width of the first bottomed groove 251 in the second direction (X-axis direction) was 0.5 mm.
  • the position of the center 251c of the first bottomed groove 251 is the center position of the width of the first bottomed groove 251 in the second direction (X-axis direction).
  • the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that when the center 251c of the first bottomed groove 251 is disposed at a position of 24% or less, the metal plate When the center 251c of the first bottomed groove 251 is placed at a position of 25% or more and 60% or less, The ratio exceeded the same ratio as that in the comparative example in which slits were not formed in the metal plate portion.
  • the ratio of the resonance amplitude of the sub-vibration part 110s to the resonance amplitude of the main vibration part 110m is such that when the center 251c of the first bottomed groove 251 is located at a position of 61% or more and 82% or less, a slit is formed in the metal plate part.
  • the ratio was the same as that in the comparative example in which no slit was formed, but when the center 251c of the first bottomed groove 251 was located at a position of 83% or more, the comparison in which no slit was formed in the metal plate part
  • the ratio rapidly increased beyond the same ratio as the ratio in the example, and increased until the center 251c of the first bottomed groove 251 reached the 96% position, that is, the position near the inner edge of the restraint part 140. .
  • the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is set to 25%. We were able to secure more than that.
  • the reason why the resonance amplitude of the sub-vibrating part 110s becomes large when the center 251c of the first bottomed groove 251 is located near the inner edge of the restraining part 140 is that the sub-vibrating part 110s is located near the inner edge of the restraining part 140 (100%).
  • the shear stress generated in the sub-vibrating part 110s is the largest at the inner edge position (100% position) of the restraint part 140, and the first bottomed groove 251 is the node point of the restraint part 140. This is because the closer the sub-vibrating portion 110s is located to the inner edge, the greater the displacement of the sub-vibrating portion 110s due to the shear stress.
  • the reason why the resonance amplitude of the sub-vibrating part 110s becomes large when the center 251c of the first bottomed groove 251 is arranged at a position of 25% or more and 60% or less is that the 25% of the second surface 2S of the metal plate part 250 At a position above 60% or less, the tensile stress generated in the sub-vibrating part 110s during resonance vibration becomes the largest, and the first bottomed groove 251 is formed at a position between 25% and 60% of the second surface 2S of the metal plate part 250. This is because the rigidity of the sub-vibrating section 110s in the second direction (X-axis direction) becomes smaller due to this, and the displacement of the sub-vibrating section 110s becomes larger.
  • the reason why the resonance amplitude of the sub-vibrating section 110s becomes small when the center 251c of the first bottomed groove 251 is arranged at a position of 61% or more and 82% or less is that the second surface 2S of the metal plate section 250 has a 61% Since the tensile stress generated in the sub-vibrating part 110s during resonance vibration is relatively small at the position of 82% or less, the sub-vibrating part 110s is formed by forming the first bottomed groove 251 at the position of 61% or more and 82% or less. This is because the effect of increasing the displacement of is reduced.
  • Figure 29 shows the finite element method for four cases in which the center of the first bottomed groove is at the 4% position, 39% position, 75% position, or 89% position, extracted from the data in Figure 28.
  • 3 is a graph showing directivity obtained by simulation analysis using In FIG. 29, the vertical axis shows the sound pressure level (dB), and the circumferential axis shows the radiation angle (°) from the center of the main vibrating section.
  • the solid line indicates the directivity when the center 251c of the first bottomed groove 251 is at the 4% position
  • the dotted line indicates the directivity when the center 251c of the first bottomed groove 251 is at the 39% position
  • the The directivity when the center 251c of the bottomed groove 251 is at the 75% position is shown by the one-dot chain line
  • the directivity when the center 251c of the first bottomed groove 251 is at the 89% position is shown by the two-dot chain line.
  • the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is relatively large. compared to when the center 251c of the first bottomed groove 251 is at the 4% or 75% position, where the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is relatively small.
  • the range of sexual angles was widening. That is, as the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m increases, the angular range of directivity becomes wider.
  • the ultrasonic transducer 200 when viewed from the first direction (Z-axis direction), the sub-vibration section 110s of the metal plate section 250 has a An extending first bottomed groove 251 is formed.
  • the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part
  • the center 251c of the first bottomed groove 251 is located at a position of 25% or more and 60% or less or 83% or more.
  • FIG. 30 is a sectional view showing a state in which the internal space formed by the metal plate part and the restraining part is filled with a damping material in the ultrasonic transducer according to Embodiment 2 of the present invention.
  • a damping material 260 such as silicone
  • the Young's modulus of the damping material 260 is, for example, 0.1 MPa or more and 100 MPa or less. From the viewpoint of suppressing the emission of unnecessary ultrasonic waves to the side opposite to the exterior side, the Young's modulus of the damping material 260 is preferably 0.1 MPa or more and 0.5 MPa or less, and from the viewpoint of suppressing reverberation, the damping material 260 The Young's modulus of the material 260 is preferably 10 MPa or more and 50 MPa or less.
  • Embodiment 3 an ultrasonic transducer according to Embodiment 3 of the present invention will be described with reference to the drawings.
  • the ultrasonic transducer according to Embodiment 3 of the present invention differs from the ultrasonic transducer according to Embodiment 2 of the present invention in that a bottomed groove is formed on the first surface of the metal plate portion.
  • the description of the configuration similar to that of the ultrasonic transducer according to the second embodiment will not be repeated.
  • FIG. 31 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 3 of the present invention.
  • an ultrasonic transducer 300 according to Embodiment 3 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 350. .
  • the outer edge of the cylinder 120 When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part
  • the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less or a position of 94% or more.
  • the depth of the second bottomed groove 351 is half the thickness of the metal plate portion 350.
  • the relationship between the position of the center 351c of the second bottomed groove 351 formed in the metal plate part 350 and the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is determined using the finite element method. We will explain the results of simulation analysis using this method.
  • FIG. 32 is a graph showing the relationship between the center position of the second bottomed groove and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section.
  • the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section
  • the horizontal axis shows the position of the center of the second bottomed groove.
  • the second direction (X) was displaced within the position range (in the axial direction).
  • the outer edge of the cylinder 120 is at the 0% position
  • the inner edge of the restraint part 140 is at the 0% position.
  • the position was set at 100%.
  • the thickness of the metal plate portion 350 is 1 mm, and the length of the vibration region of the sub-vibrating portion 110s in the second direction (X-axis direction), that is, the length of the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction).
  • the interval was 7 mm, and the width of the second bottomed groove 351 in the second direction (X-axis direction) was 0.5 mm.
  • the position of the center 351c of the second bottomed groove 351 is the center position of the width of the second bottomed groove 351 in the second direction (X-axis direction).
  • the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that when the center 351c of the second bottomed groove 351 is disposed at a position of 15% or less, the metal plate When the center 351c of the second bottomed groove 351 is located at a position of 16% or more and 76% or less, The ratio exceeded the same ratio as that in the comparative example in which slits were not formed in the metal plate portion.
  • the ratio of the resonance amplitude of the sub-vibration part 110s to the resonance amplitude of the main vibration part 110m is such that when the center 351c of the second bottomed groove 351 is located at a position of 77% or more and 93% or less, a slit is formed in the metal plate part.
  • the ratio was similar to that in the comparative example in which no slit was formed, but when the center 351c of the second bottomed groove 351 was located at a position of 94% or more, the comparison in which no slit was formed in the metal plate part It exceeded a ratio that is comparable to the ratio in the example.
  • the reason why the resonance amplitude of the sub-vibrating part 110s becomes large when the center 351c of the second bottomed groove 351 is located near the inner edge of the restraint part 140 is that the sub-vibrating part 110s is located at the inner edge of the restraint part 140 (100%).
  • the shear stress generated in the sub-vibrating part 110s is the largest at the inner edge position (100% position) of the restraint part 140, and the second bottomed groove 351 is the node point of the restraint part 140. This is because the closer the sub-vibrating portion 110s is located to the inner edge, the greater the displacement of the sub-vibrating portion 110s due to the shear stress.
  • the second bottomed groove 351 is formed on the first surface 1S of the metal plate part 350, the first bottomed groove 251 formed on the second surface 2S of the metal plate part 250 according to the second embodiment Compared to this, the effect of increasing the displacement of the sub-vibrating section 110s due to the shear stress is reduced.
  • the reason why the resonance amplitude of the sub-vibrating section 110s becomes large when the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less is that the 16% of the first surface 1S of the metal plate section 350 At a position above 76% or less, the tensile stress generated in the sub-vibrating part 110s during resonance vibration becomes the largest, and by forming the second bottomed groove 351 at a position between 16% and 76%, This is because the rigidity in the second direction (X-axis direction) becomes smaller and the displacement of the sub-vibrating section 110s becomes larger.
  • the reason why the resonance amplitude of the sub-vibrating part 110s becomes small when the center 351c of the second bottomed groove 351 is arranged at a position of 77% or more and 93% or less is that the 77% of the first surface 1S of the metal plate part 350 Since the tensile stress generated in the sub-vibrating part 110s during resonance vibration is relatively small at the position of 93% or less, the second bottomed groove 351 is formed at the position of 77% or more and 93% or less. This is because the effect of increasing the displacement of is reduced.
  • Figure 33 shows the directivity analyzed by simulation using the finite element method for four cases in which the center of the second bottomed groove is at the 4% position, 46% position, 82% position, or 96% position. This is a graph showing.
  • the vertical axis shows the sound pressure level (dB)
  • the circumferential axis shows the radiation angle (°) from the center of the main vibrating section.
  • the solid line represents the directivity when the center 351c of the second bottomed groove 351 is at the 4% position
  • the dotted line represents the directivity when the center 351c of the second bottomed groove 351 is at the 46% position
  • the second The directivity when the center 351c of the bottomed groove 351 is at the 82% position is shown by the one-dot chain line
  • the directivity when the center 351c of the second bottomed groove 351 is at the 96% position is shown by the two-dot chain line.
  • the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is relatively large. compared to when the center 351c of the second bottomed groove 351 is at the 4% or 82% position, where the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is relatively small.
  • the range of sexual angles was widening. That is, as the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m increases, the angular range of directivity becomes wider.
  • the ultrasonic transducer 300 when viewed from the first direction (Z-axis direction), the sub-vibration section 110s of the metal plate section 350 has a An extending second bottomed groove 351 is formed.
  • the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part
  • the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less or a position of 94% or more.
  • the distribution in the first direction (Z-axis direction) of the stress in the second direction (X-axis direction) that occurs at 46% of the metal plate portion during resonance vibration of the sub-vibration section 110s is simulated using the finite element method.
  • the results of the analysis will be explained.
  • the thickness of the exterior part 110 in the part where the recess 112 is formed was 1 mm
  • the thickness of the metal plate part was 1 mm
  • the material of the exterior part 110 was polypropylene
  • the material of the metal plate part was an aluminum alloy.
  • FIG. 34 is a graph showing the relationship between the position from the second surface in the first direction and the stress in the second direction that occurs at a 46% position of the metal plate part during resonance vibration of the sub-vibrating part.
  • the vertical axis shows the stress (kPa) in the second direction that occurs at the 46% position of the metal plate part during resonance vibration of the sub-vibrating part
  • the horizontal axis shows the position (kPa) in the first direction from the second surface. mm) is shown.
  • the stress La in the second direction (X-axis direction) in the range of 0 mm or more and 1 mm or less from the second surface 2S in the first direction (Z-axis direction) is stress generated in the metal plate portion.
  • the stress Lb in the second direction (X-axis direction) in the range of more than 1 mm and less than 2 mm from the second surface 2S in the first direction (Z-axis direction) is stress generated in the exterior portion 110.
  • the above-mentioned stress Lb was approximately 0, and most of the stress generated during resonance vibration of the sub-vibration section 110s was generated in the metal plate section.
  • the polarity of the stress is opposite between the upper side and the lower side of the sub-vibrating section 110s.
  • the above-mentioned stress La has a polarity at a position 0.55 mm from the second surface 2S in the first direction (Z-axis direction), which is approximately the center of the thickness of the metal plate portion. It was the opposite. Stress La with positive polarity is tensile stress, and stress La with negative polarity is compressive stress.
  • tensile stress is generated in the metal plate portion in the range of 0 mm or more and 0.55 mm or less from the second surface 2S in the first direction (Z-axis direction), and the second surface 2S in the first direction (Z-axis direction) Compressive stress was generated in the metal plate portion within a range of more than 0.55 mm and 1 mm or less from the point.
  • the resonance amplitude of the sub-vibrating part 110s varies depending on the depth of the bottomed groove formed in the metal plate part, but there is a region where tensile stress occurs.
  • the fluctuation tendency of the resonance amplitude of the sub-vibrating portion 110s is determined depending on where the bottomed groove is mainly located between the region where the bottomed groove is located and the region where compressive stress occurs.
  • the depth of the first bottomed groove 251 according to the second embodiment is 0.3 mm
  • the first bottomed groove 251 is formed only in a region where tensile stress occurs, the bending displacement due to the tensile stress
  • the resonance amplitude of the sub-vibrating section 110s increases due to the increase in .
  • the first bottomed groove 251 When the depth of the first bottomed groove 251 according to the second embodiment is 0.7 mm, the first bottomed groove 251 is formed in both a region where tensile stress occurs and a region where compressive stress occurs; Since the portion formed in the region where stress occurs occupies most of the first bottomed groove 251, the resonance amplitude of the sub-vibrating portion 110s increases due to an increase in bending displacement due to the tensile stress.
  • the second bottomed groove 351 according to the third embodiment when the depth of the second bottomed groove 351 according to the third embodiment is 0.3 mm, the second bottomed groove 351 is formed only in a region where compressive stress occurs, so that the bending displacement due to the compressive stress The resonance amplitude of the sub-vibrating section 110s increases due to the increase in .
  • the depth of the second bottomed groove 351 according to the third embodiment is 0.7 mm, the second bottomed groove 351 is formed in both a region where compressive stress occurs and a region where tensile stress occurs; Since the portion formed in the region where stress occurs occupies most of the second bottomed groove 351, the resonance amplitude of the sub-vibrating portion 110s increases due to an increase in bending displacement due to the compressive stress.
  • the depth of the first bottomed groove 251 is not limited to half the thickness of the metal plate portion 250, but may be between 30% and 70% of the thickness of the metal plate portion 250. Good too.
  • the depth of the second bottomed groove 351 is not limited to half the thickness of the metal plate portion 350, but may be between 30% and 70% of the thickness of the metal plate portion 350. good.
  • each of the first bottomed groove 251 and the second bottomed groove 351 in the second direction increases, the effect of increasing the resonance amplitude of the sub-vibration section 110s increases; The effect of stabilizing the temperature characteristics of the acoustic wave transducer is reduced.
  • the width and depth of the bottomed groove are approximately the same, or that the width of the bottomed groove and the thickness of the metal plate portion are approximately the same.
  • Embodiment 4 An ultrasonic transducer according to Embodiment 4 of the present invention will be described below with reference to the drawings.
  • the ultrasonic transducer according to Embodiment 4 of the present invention is characterized in that both the first bottomed groove and the second bottomed groove are formed in the metal plate portion. Since this embodiment differs from the sonic transducer, the description of the configuration that is similar to the ultrasonic transducer according to Embodiment 2 or 3 of the present invention will not be repeated.
  • FIG. 35 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 4 of the present invention.
  • an ultrasonic transducer 400 according to Embodiment 4 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 450. .
  • a first vibration part extending in the third direction (Y-axis direction) is located at a position that becomes the sub-vibrating part 110s of the metal plate part 450 when viewed from the first direction (Z-axis direction).
  • a bottomed groove 251 is formed.
  • the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part
  • the center 251c of the first bottomed groove 251 is located at a position of 25% or more and 60% or less or 83% or more.
  • the depth of the first bottomed groove 251 is half the thickness of the metal plate portion 450.
  • a second vibration part extending in the third direction is located at a position that becomes the sub-vibration part 110s of the metal plate part 450 when viewed from the first direction (Z-axis direction).
  • a bottomed groove 351 is formed.
  • the outer edge of the cylinder 120 When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less or a position of 94% or more. In this embodiment, the depth of the second bottomed groove 351 is half the thickness of the metal plate portion 450.
  • FIG. 36 shows an ultrasonic transducer in which no bottomed groove is formed in the metal plate part, an ultrasonic transducer in which only the first bottomed groove is formed in the metal plate part, and an ultrasonic transducer in which only the second bottomed groove is formed in the metal plate part.
  • This is a graph showing the characteristics.
  • the vertical axis shows the sound pressure level (dB)
  • the circumferential axis shows the radiation angle (°) from the center of the main vibrating section.
  • the solid line represents the directivity of the ultrasonic transducer in which the bottomed groove is not formed in the metal plate part
  • the dotted line represents the directivity of the ultrasonic transducer in which only the first bottomed groove is formed in the metal plate part.
  • the one-dot chain line represents the directivity of the ultrasonic transducer in which only the second bottomed groove is formed
  • the directivity of the ultrasonic transducer in which the first and second bottomed grooves are formed in the metal plate is shown by the dashed line. It is shown by a two-dot chain line.
  • the angular range of directivity of the ultrasonic transducer 400 according to this embodiment in which the first bottomed groove 251 and the second bottomed groove 351 are formed in the metal plate portion 450 is different from that of the other three. It was wider than the ultrasonic transducer.
  • the ultrasonic transducer 400 it is possible to downsize the ultrasonic transducer 400 while ensuring a wide angular range of directivity.
  • FIG. 37 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to a modification of Embodiment 4 of the present invention.
  • an ultrasonic transducer 400a according to a modification of Embodiment 4 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 450a. Equipped with.
  • the metal plate portion 450a has a first bottomed groove 251 and a center 251c arranged at a position of 25% or more and 60% or less when viewed from the first direction (Z-axis direction).
  • the first surface 1S of the metal plate portion 450a has a second bottomed groove whose center 351c is located at a position of 16% to 76% or 94% or more when viewed from the first direction (Z-axis direction). 351 is formed. Note that the second bottomed groove 351 and the center of the metal plate portion 450a are arranged as second bottomed grooves, with the center 351c located at a position of 16% or more and 76% or less when viewed from the first direction (Z-axis direction). Each of the second bottomed grooves 351 arranged at a position where 351c is 94% or more may be formed on the first surface 1S.
  • the main vibrating portion which is a portion of the exterior portion and the metal plate portion located inside the cylinder, is different from the ultrasonic vibrator in the first direction.
  • a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
  • a metal plate is provided at a position of the metal plate portion that becomes the sub-vibration portion, and is parallel to the outer edge of the cylinder while penetrating the metal plate portion and perpendicular to each of the first direction and the second direction.
  • a slit extending in a third direction is formed, When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position.
  • the center of the slit In the ultrasonic transducer, the center of the slit is located at a position of 35% or more.
  • the main vibrating portion which is a portion of the exterior portion and the metal plate portion located inside the cylinder, is different from the ultrasonic vibrator in the first direction.
  • a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction.
  • the first direction and the second a first bottomed groove extending parallel to the outer edge of the cylindrical body in a third direction perpendicular to each direction;
  • the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position.
  • the center of the first bottomed groove is located at a position of 25% or more and 60% or less or 83% or more.
  • the main vibrating portion which is a portion of the exterior portion and the metal plate portion located inside the cylinder, is different from the ultrasonic vibrator in the first direction.
  • a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
  • a first surface perpendicular to each of the first direction and the second direction is provided.
  • a second bottomed groove is formed that extends in parallel to the outer edge of the cylindrical body in three directions, When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position.
  • the center of the second bottomed groove is located at a position of 16% or more and 76% or less or a position of 94% or more.
  • a second bottomed groove extending parallel to the outer edge of the cylindrical body in the third direction is formed at a position of the metal plate section that becomes the sub-vibration section when viewed from the first direction.
  • the first bottomed groove includes a first bottomed groove whose center is located at a position of 25% to 60% when viewed from the first direction, and a first bottomed groove whose center is located at a position of 83% or more.
  • the resonance frequency of the fundamental mode of the restraining portion is 20% or more lower than the resonance frequency of the ultrasonic transducer
  • the ultrasonic vibrator includes two laminated piezoelectric bodies, Each of the two piezoelectric bodies is configured to be sandwiched between a first electrode and a second electrode so that an alternating current voltage can be applied thereto, The first electrode is fixed to a ground potential, Each of the cylinder body and the restraint part is made of metal, The first electrode, the cylindrical body, the metal plate part, and the restraint part are mechanically and electrically connected to each other to constitute an electromagnetic shield, and in any one of ⁇ 1> to ⁇ 6>. Ultrasonic transducer as described.
  • the exterior part is made of resin whose main component is polypropylene
  • the metal plate portion is made of an aluminum alloy, Any one of ⁇ 1> to ⁇ 7>, wherein the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part is 100% or more and 160% or less.
  • the ultrasonic transducer according to any one of the above.
  • the exterior part is made of resin mainly composed of polypropylene
  • the metal plate portion is made of stainless steel, Any one of ⁇ 1> to ⁇ 7>, wherein the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part is 60% or more and 100% or less.
  • the ultrasonic transducer according to any one of the above.
  • 1S 1st surface, 2S 2nd surface, 10 processing circuit 100, 100a, 100b, 200, 300, 400, 400a ultrasonic transducer, 110 exterior part, 110m main vibration part, 110s sub vibration part, 111 inner surface, 112 concave part , 120, 120a Cylindrical body, 130, 130a, 130b, 130c Ultrasonic transducer, 131 Piezoelectric body, 132 First electrode, 133 Second electrode, 134 Intermediate electrode, 135 Vibration plate, 140 Restraint part, 150, 150b, 150c , 150d, 150e, 150f, 250, 350, 450, 450a metal plate part, 151 slit, 251 first bottomed groove, 260 damping material, 351 second bottomed groove, MS main sound source, SS sub sound source.

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  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
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  • Health & Medical Sciences (AREA)
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  • Transducers For Ultrasonic Waves (AREA)

Abstract

When seen in a first direction, a slit (151) penetrating a metal plate part (150) and extending in a third direction is formed at the position of a sub-vibration part (110s) of the metal plate part (150). When seen in the first direction, supposing that the position of the outer edge of a cylinder (120) is defined as position of 0% and the position of the inner edge of a constraint part (140) is defined as position of 100% in a positional range between the cylinder (120) and the constraint part (140) in a second direction, the center (151c) of the slit (151) is located at a position of 35% or more.

Description

超音波トランスデューサultrasonic transducer
　本発明は、超音波トランスデューサに関する。 The present invention relates to an ultrasonic transducer.
　超音波センサの構成を開示した先行文献として、特開２００７－１４２９６７号公報(特許文献１)がある。特許文献１に記載された超音波センサは、車両用バンパまたは樹脂部分の内面側に取り付けられる。超音波センサは、超音波振動子と、筐体とを有する。超音波振動子は、超音波を送受信する。筐体は、超音波振動子を収容する。筐体の底面部の内面に超音波振動子を接触させて固定するとともに、当該底面部の外面が、車両用バンパまたは樹脂部分の内面に当接する。 As a prior document disclosing the configuration of an ultrasonic sensor, there is Japanese Patent Application Publication No. 2007-142967 (Patent Document 1). The ultrasonic sensor described in Patent Document 1 is attached to the inner surface of a vehicle bumper or a resin portion. The ultrasonic sensor includes an ultrasonic transducer and a housing. The ultrasonic transducer transmits and receives ultrasonic waves. The housing houses the ultrasonic transducer. The ultrasonic transducer is fixed in contact with the inner surface of the bottom surface of the casing, and the outer surface of the bottom surface abuts against the inner surface of the vehicle bumper or the resin portion.
　筐体の底面部の一部に、超音波伝達部が形成されている。超音波伝達部は、車両用バンパまたは樹脂部分と、超音波振動子とに接触するように配置されている。超音波伝達部は、筐体の材質とは異なる材質であって、超音波振動子の音響インピーダンスと、車両用バンパまたは樹脂部分の音響インピーダンスとの中間の音響インピーダンスを有する材質からなる。超音波センサは、超音波の送受信を、超音波伝達部および車両用バンパまたは樹脂部分を介して行なう。 An ultrasonic transmission section is formed in a part of the bottom surface of the casing. The ultrasonic transmission section is arranged so as to be in contact with the vehicle bumper or the resin part and the ultrasonic vibrator. The ultrasonic transmission section is made of a material different from the material of the casing, and is made of a material having an acoustic impedance intermediate between the acoustic impedance of the ultrasonic transducer and the acoustic impedance of the vehicle bumper or resin portion. The ultrasonic sensor transmits and receives ultrasonic waves via an ultrasonic transmission section and a vehicle bumper or resin part.
特開２００７－１４２９６７号公報Japanese Patent Application Publication No. 2007-142967
　超音波トランスデューサにおいては、指向性の角度範囲を広く確保しつつ小型化することが求められている。 Ultrasonic transducers are required to be miniaturized while ensuring a wide directional angular range.
　本発明は上記の課題に鑑みてなされたものであって、指向性の角度範囲を広く確保しつつ小型化することができる、超音波トランスデューサを提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic transducer that can be downsized while ensuring a wide angular range of directivity.
　本発明の第１局面に基づく超音波トランスデューサは、外装部と、金属板部と、筒体と、超音波振動子と、拘束部とを備える。外装部は、取付面を有する。金属板部は、上記取付面に取り付けられ、上記取付面に沿って延在している。筒体は、金属板部に取り付けられている。超音波振動子は、筒体に取り付けられており、金属板部に間隔をあけて対向する。拘束部は、金属板部に取り付けられており、筒体に一定の間隔をあけて筒体を挟んでいる。上記取付面に直交する第１方向から見て外装部および金属板部における筒体の内側に位置する部分であるメイン振動部は、超音波振動子とは上記第１方向において逆位相で共振振動する。上記第１方向から見て、上記第１方向と直交する第２方向において外装部および金属板部における筒体の外側かつ拘束部の内側に位置する部分であるサブ振動部は、メイン振動部とは上記第１方向において逆位相で共振振動する。上記第１方向から見て、金属板部のサブ振動部となる位置に、金属板部を貫通しつつ筒体の上記第１方向および上記第２方向の各々に直交する第３方向に延在するスリットが形成されている。上記第１方向から見て、筒体と拘束部との間における上記第２方向の位置範囲において筒体の外縁を０％の位置とするとともに拘束部の内縁を１００％の位置としたとき、スリットの中心は、３５％以上の位置に配置されている。 The ultrasonic transducer according to the first aspect of the present invention includes an exterior portion, a metal plate portion, a cylinder, an ultrasonic vibrator, and a restraining portion. The exterior part has a mounting surface. The metal plate portion is attached to the mounting surface and extends along the mounting surface. The cylindrical body is attached to the metal plate part. The ultrasonic transducer is attached to the cylindrical body, and faces the metal plate part with an interval therebetween. The restraint part is attached to the metal plate part and sandwiches the cylinder at a constant interval. The main vibrating part, which is a part of the exterior part and the metal plate part located inside the cylindrical body when viewed from the first direction perpendicular to the mounting surface, resonates with the ultrasonic transducer in an opposite phase in the first direction. do. When viewed from the first direction, the sub-vibration part is a part of the exterior part and the metal plate part located outside the cylinder and inside the restraint part in a second direction orthogonal to the first direction. vibrates resonantly with opposite phases in the first direction. When viewed from the first direction, the metal plate extends in a third direction perpendicular to each of the first direction and the second direction of the cylindrical body while penetrating the metal plate at a position that becomes the sub-vibrating part of the metal plate. A slit is formed. Viewed from the first direction, when the outer edge of the cylinder is at the 0% position and the inner edge of the restraint is at the 100% position in the position range in the second direction between the cylinder and the restraint part, The center of the slit is located at a position of 35% or more.
　本発明の第２局面に基づく超音波トランスデューサは、外装部と、金属板部と、筒体と、超音波振動子と、拘束部とを備える。外装部は、取付面を有する。金属板部は、上記取付面に取り付けられ、上記取付面に沿って延在している。筒体は、金属板部に取り付けられている。超音波振動子は、筒体に取り付けられており、金属板部に間隔をあけて対向する。拘束部は、金属板部に取り付けられており、筒体に一定の間隔をあけて筒体を挟んでいる。上記取付面に直交する第１方向から見て外装部および金属板部における筒体の内側に位置する部分であるメイン振動部は、超音波振動子とは上記第１方向において逆位相で共振振動する。上記第１方向から見て、上記第１方向と直交する第２方向において外装部および金属板部における筒体の外側かつ拘束部の内側に位置する部分であるサブ振動部は、メイン振動部とは上記第１方向において逆位相で共振振動する。金属板部における外装部側の第１面とは反対の第２面において、上記第１方向から見て金属板部のサブ振動部となる位置に、上記第１方向および上記第２方向の各々に直交する第３方向に延在する第１有底溝が形成されている。上記第１方向から見て、筒体と拘束部との間における上記第２方向の位置範囲において筒体の外縁を０％の位置とするとともに拘束部の内縁を１００％の位置としたとき、第１有底溝の中心は、２５％以上６０％以下の位置または８３％以上の位置に配置されている。 The ultrasonic transducer according to the second aspect of the present invention includes an exterior portion, a metal plate portion, a cylinder, an ultrasonic vibrator, and a restraining portion. The exterior part has a mounting surface. The metal plate portion is attached to the mounting surface and extends along the mounting surface. The cylindrical body is attached to the metal plate part. The ultrasonic transducer is attached to the cylindrical body, and faces the metal plate part with an interval therebetween. The restraint part is attached to the metal plate part and sandwiches the cylinder at a constant interval. The main vibrating part, which is a part of the exterior part and the metal plate part located inside the cylindrical body when viewed from the first direction perpendicular to the mounting surface, resonates with the ultrasonic transducer in an opposite phase in the first direction. do. When viewed from the first direction, the sub-vibration part is a part of the exterior part and the metal plate part located outside the cylinder and inside the restraint part in a second direction orthogonal to the first direction. vibrates resonantly with opposite phases in the first direction. On a second surface of the metal plate portion opposite to the first surface on the exterior side, at a position that becomes a sub-vibration portion of the metal plate portion when viewed from the first direction, in each of the first direction and the second direction. A first bottomed groove is formed extending in a third direction orthogonal to the first bottomed groove. Viewed from the first direction, when the outer edge of the cylinder is at the 0% position and the inner edge of the restraint is at the 100% position in the position range in the second direction between the cylinder and the restraint part, The center of the first bottomed groove is disposed at a position of 25% or more and 60% or less or a position of 83% or more.
　本発明の第３局面に基づく超音波トランスデューサは、外装部と、金属板部と、筒体と、超音波振動子と、拘束部とを備える。外装部は、取付面を有する。金属板部は、上記取付面に取り付けられ、上記取付面に沿って延在している。筒体は、金属板部に取り付けられている。超音波振動子は、筒体に取り付けられており、金属板部に間隔をあけて対向する。拘束部は、金属板部に取り付けられており、筒体に一定の間隔をあけて筒体を挟んでいる。上記取付面に直交する第１方向から見て外装部および金属板部における筒体の内側に位置する部分であるメイン振動部は、超音波振動子とは上記第１方向において逆位相で共振振動する。上記第１方向から見て、上記第１方向と直交する第２方向において外装部および金属板部における筒体の外側かつ拘束部の内側に位置する部分であるサブ振動部は、メイン振動部とは上記第１方向において逆位相で共振振動する。金属板部における外装部側の第１面において、上記第１方向から見て金属板部のサブ振動部となる位置に、上記第１方向および上記第２方向の各々に直交する第３方向に延在する第２有底溝が形成されている。上記第１方向から見て、筒体と拘束部との間における上記第２方向の位置範囲において筒体の外縁を０％の位置とするとともに拘束部の内縁を１００％の位置としたとき、第２有底溝の中心は、１６％以上７６％以下の位置または９４％以上の位置に配置されている。 The ultrasonic transducer according to the third aspect of the present invention includes an exterior portion, a metal plate portion, a cylinder, an ultrasonic vibrator, and a restraining portion. The exterior part has a mounting surface. The metal plate portion is attached to the mounting surface and extends along the mounting surface. The cylindrical body is attached to the metal plate part. The ultrasonic transducer is attached to the cylindrical body, and faces the metal plate part with an interval therebetween. The restraint part is attached to the metal plate part and sandwiches the cylinder at a constant interval. The main vibrating part, which is a part of the exterior part and the metal plate part located inside the cylindrical body when viewed from the first direction perpendicular to the mounting surface, resonates with the ultrasonic transducer in an opposite phase in the first direction. do. When viewed from the first direction, the sub-vibration part is a part of the exterior part and the metal plate part located outside the cylinder and inside the restraint part in a second direction orthogonal to the first direction. vibrates resonantly with opposite phases in the first direction. On the first surface of the metal plate part on the exterior part side, at a position that becomes the sub-vibration part of the metal plate part when viewed from the first direction, in a third direction perpendicular to each of the first direction and the second direction. An extending second bottomed groove is formed. Viewed from the first direction, when the outer edge of the cylinder is at the 0% position and the inner edge of the restraint is at the 100% position in the position range in the second direction between the cylinder and the restraint part, The center of the second bottomed groove is located at a position of 16% or more and 76% or less or a position of 94% or more.
　本発明によれば、超音波トランスデューサにおいて指向性の角度範囲を広く確保しつつ小型化することができる。 According to the present invention, it is possible to downsize an ultrasonic transducer while ensuring a wide directional angular range.
本発明の実施形態１に係る超音波トランスデューサの構成を示す縦断面図である。1 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 1 of the present invention. 本発明の実施形態１に係る超音波トランスデューサの構成を示す分解斜視図である。FIG. 1 is an exploded perspective view showing the configuration of an ultrasonic transducer according to Embodiment 1 of the present invention. 本発明の実施形態１に係る超音波トランスデューサが備える超音波振動子の構成を示す断面図である。FIG. 2 is a cross-sectional view showing the configuration of an ultrasonic transducer included in the ultrasonic transducer according to Embodiment 1 of the present invention. 拘束部が基本モードで共振している状態を第１方向から見た平面図である。FIG. 3 is a plan view of a state in which the restraining portion is resonating in a fundamental mode when viewed from a first direction. 拘束部が高次モードで共振している状態を第１方向から見た平面図である。FIG. 7 is a plan view of a state in which the restraint section is resonating in a higher order mode when viewed from a first direction. 本発明の実施形態１に係る超音波トランスデューサが超音波を送信または受信しているときの、有限要素法を用いてシミュレーション解析した変位状態を示す斜視図である。FIG. 2 is a perspective view showing a displacement state simulated and analyzed using the finite element method when the ultrasonic transducer according to Embodiment 1 of the present invention is transmitting or receiving ultrasonic waves. 図６の超音波トランスデューサをＶＩＩ－ＶＩＩ線矢印方向から見た断面図である。7 is a cross-sectional view of the ultrasonic transducer of FIG. 6 viewed from the direction of the arrow VII-VII. FIG. メイン音源の両側に、メイン音源とは逆位相で振動するサブ音源を配置した状態を示す模式図である。FIG. 3 is a schematic diagram showing a state in which sub sound sources that vibrate in an opposite phase to the main sound source are arranged on both sides of the main sound source. メイン音源とサブ音源との間の距離を４ｍｍ、６ｍｍおよび８ｍｍの３種類に変化させて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。It is a graph showing the directivity obtained by simulation analysis using the finite element method while changing the distance between the main sound source and the sub sound source into three types: 4 mm, 6 mm, and 8 mm. スリットの中心の位置と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。7 is a graph showing the relationship between the position of the center of the slit and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section. 図１０のデータから抽出した、スリットの中心が１９％の位置、６９％の位置または９４％の位置である３つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。11 is a graph showing directivity obtained by simulation analysis using the finite element method for three cases in which the center of the slit is at the 19% position, the 69% position, or the 94% position, extracted from the data in FIG. 10. サブ振動部の共振周波数からメイン振動部の共振周波数を引いた差分と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。It is a graph showing the relationship between the difference obtained by subtracting the resonance frequency of the main vibration section from the resonance frequency of the sub vibration section and the ratio of the resonance amplitude of the sub vibration section to the resonance amplitude of the main vibration section. 筒体と拘束部との間隔と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。It is a graph which shows the relationship between the space|interval of a cylinder and a restraint part, and the ratio of the resonance amplitude of a sub-vibration part to the resonance amplitude of a main vibration part. 第１変形例に係る超音波振動子の構成を示す断面図である。FIG. 7 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a first modification. 第１変形例に係る超音波トランスデューサ、および、拘束部が絶縁材料で構成されている点のみ第１変形例に係る超音波トランスデューサとは異なる参考例に係る超音波トランスデューサの、各々における超音波振動子から生ずるノイズの大きさを示すグラフである。Ultrasonic vibrations in the ultrasonic transducer according to the first modified example and the ultrasonic transducer according to the reference example, which differs from the ultrasonic transducer according to the first modified example only in that the restraint part is made of an insulating material. 3 is a graph showing the magnitude of noise generated from children. 第２変形例に係る超音波振動子の構成を示す断面図である。It is a sectional view showing the composition of the ultrasonic transducer concerning the 2nd modification. 第３変形例に係る超音波振動子の構成を示す断面図である。It is a sectional view showing the composition of the ultrasonic transducer concerning the 3rd modification. 本発明の実施形態１の第４変形例に係る超音波トランスデューサの構成を示す縦断面図である。FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a fourth modification of Embodiment 1 of the present invention. 本発明の実施形態１の第５変形例に係る超音波トランスデューサの構成を示す縦断面図である。FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a fifth modification of Embodiment 1 of the present invention. 第１実施例に係る金属板部および拘束部を示す斜視図である。It is a perspective view showing a metal plate part and a restraint part concerning a 1st example. 第２実施例に係る金属板部および拘束部を示す斜視図である。It is a perspective view which shows the metal plate part and restraint part based on 2nd Example. 第３実施例に係る金属板部および拘束部を示す斜視図である。FIG. 7 is a perspective view showing a metal plate part and a restraint part according to a third embodiment. 第４実施例に係る金属板部および拘束部を示す斜視図である。It is a perspective view which shows the metal plate part and restraint part based on 4th Example. 超音波振動子の長さに対するスリットの延在長さの比率と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。It is a graph showing the relationship between the ratio of the extension length of the slit to the length of the ultrasonic transducer and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section. メイン振動部およびサブ振動部の各々を構成する部分の外装部の厚みに対する金属板部の厚みの比率と、超音波振動子の第１方向の単位変位当たりのサブ振動部に作用する応力およびサブ振動部の共振振幅の各々との関係を示すグラフである。The ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part, the stress acting on the sub-vibrating part per unit displacement in the first direction of the ultrasonic vibrator, and the sub-vibrating part It is a graph which shows the relationship between each resonance amplitude of a vibrating part. 本発明の実施形態１の第６変形例に係る超音波トランスデューサが備える、金属板部、筒体および拘束部を示す縦断面図である。It is a longitudinal cross-sectional view showing a metal plate part, a cylindrical body, and a restraint part with which an ultrasonic transducer according to a sixth modification of Embodiment 1 of the present invention is provided. 本発明の実施形態２に係る超音波トランスデューサの構成を示す縦断面図である。FIG. 3 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 2 of the present invention. 第１有底溝の中心の位置と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。It is a graph which shows the relationship between the position of the center of a 1st bottomed groove, and the ratio of the resonance amplitude of a sub-vibration part to the resonance amplitude of a main vibration part. 図２８のデータから抽出した、第１有底溝の中心が４％の位置、３９％の位置、７５％の位置または８９％の位置である４つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。Simulation analysis using the finite element method for four cases in which the center of the first bottomed groove is at the 4% position, 39% position, 75% position, or 89% position extracted from the data in Figure 28 This is a graph showing the directivity. 本発明の実施形態２に係る超音波トランスデューサにおいて金属板部と拘束部とによって形成された内部空間がダンピング材で埋められた状態を示す断面図である。FIG. 7 is a cross-sectional view showing a state in which an internal space formed by a metal plate part and a restraining part is filled with a damping material in an ultrasonic transducer according to a second embodiment of the present invention. 本発明の実施形態３に係る超音波トランスデューサの構成を示す縦断面図である。FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 3 of the present invention. 第２有底溝の中心の位置と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。It is a graph which shows the relationship between the position of the center of a 2nd bottomed groove, and the ratio of the resonance amplitude of a sub-vibration part to the resonance amplitude of a main vibration part. 第２有底溝の中心が４％の位置、４６％の位置、８２％の位置または９６％の位置である４つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。It is a graph showing directivity analyzed by simulation using the finite element method for four cases in which the center of the second bottomed groove is at the 4% position, 46% position, 82% position, or 96% position. . 第１方向における第２面からの位置と、サブ振動部の共振振動時に金属板部の４６％の位置に生ずる第２方向の応力との関係を示すグラフである。It is a graph showing the relationship between the position from the second surface in the first direction and the stress in the second direction that occurs at a 46% position of the metal plate part during resonance vibration of the sub-vibrating part. 本発明の実施形態４に係る超音波トランスデューサの構成を示す縦断面図である。FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 4 of the present invention. 金属板部に有底溝が形成されていない超音波トランスデューサ、金属板部に第１有底溝のみが形成されている超音波トランスデューサ、金属板部に第２有底溝のみが形成されている超音波トランスデューサ、および、金属板部に第１有底溝および第２有底溝が形成されている超音波トランスデューサの、４つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。An ultrasonic transducer in which a bottomed groove is not formed in the metal plate part, an ultrasonic transducer in which only a first bottomed groove is formed in the metal plate part, and an ultrasonic transducer in which only a second bottomed groove is formed in the metal plate part. A graph showing the directivity obtained by simulation analysis using the finite element method for four cases of an ultrasonic transducer and an ultrasonic transducer in which a first bottomed groove and a second bottomed groove are formed in the metal plate part. It is. 本発明の実施形態４の変形例に係る超音波トランスデューサの構成を示す縦断面図である。FIG. 7 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to a modification of Embodiment 4 of the present invention.
　以下、本発明の各実施形態に係る超音波トランスデューサについて図面を参照して説明する。以下の実施形態の説明においては、図中の同一または相当部分には同一符号を付して、その説明は繰り返さない。 Hereinafter, ultrasonic transducers according to each embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the figures are denoted by the same reference numerals, and the description thereof will not be repeated.
　(実施形態１)
　図１は、本発明の実施形態１に係る超音波トランスデューサの構成を示す縦断面図である。図２は、本発明の実施形態１に係る超音波トランスデューサの構成を示す分解斜視図である。図１および図２に示すように、本発明の実施形態１に係る超音波トランスデューサ１００は、外装部１１０と、金属板部１５０と、筒体１２０と、超音波振動子１３０と、拘束部１４０とを備える。 (Embodiment 1)
FIG. 1 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view showing the configuration of the ultrasonic transducer according to Embodiment 1 of the present invention. As shown in FIGS. 1 and 2, the ultrasonic transducer 100 according to the first embodiment of the present invention includes an exterior portion 110, a metal plate portion 150, a cylinder 120, an ultrasonic transducer 130, and a restraining portion 140. Equipped with.
　外装部１１０は、たとえば、車両用バンパ、パソコンもしくはスマートホンの筐体、家具、または、家の壁などの外装の一部である。外装部１１０は、内面１１１を有する。外装部１１０は、略平板状の形状を有している。外装部１１０は、ポリプロピレンなどを主成分とする樹脂で構成されている。外装部１１０の内面１１１に、凹部１１２が形成されている。外装部１１０の厚みは、たとえば、３ｍｍであり、凹部１１２が形成されている部分の外装部１１０の厚みは、たとえば、１ｍｍである。なお、凹部１１２は、外装部１１０に必ずしも形成されていなくてもよい。 The exterior part 110 is, for example, a part of the exterior of a vehicle bumper, the casing of a personal computer or a smartphone, furniture, or a wall of a house. Exterior portion 110 has an inner surface 111. The exterior portion 110 has a substantially flat plate shape. The exterior portion 110 is made of resin whose main component is polypropylene or the like. A recess 112 is formed in the inner surface 111 of the exterior part 110. The thickness of the exterior portion 110 is, for example, 3 mm, and the thickness of the portion of the exterior portion 110 where the recessed portion 112 is formed is, for example, 1 mm. Note that the recess 112 does not necessarily have to be formed in the exterior part 110.
　図中においては、外装部１１０の内面１１１に直交する第１方向をＺ軸方向、第１方向に直交する第２方向をＸ軸方向、第１方向および第２方向の各々に直交する第３方向をＹ軸方向として示している。 In the figure, the first direction perpendicular to the inner surface 111 of the exterior part 110 is the Z-axis direction, the second direction perpendicular to the first direction is the X-axis direction, and the third direction is perpendicular to each of the first and second directions. The direction is shown as the Y-axis direction.
　金属板部１５０は、平板状である。金属板部１５０は、外装部１１０の取付面である内面１１１に取り付けられ、外装部１１０の内面１１１に沿って延在している。本実施形態においては、金属板部１５０は、凹部１１２内に取り付けられている。金属板部１５０は、アルミニウムを含むジェラルミンなどのアルミニウム合金、または、ステンレス鋼などの金属で構成されている。金属板部１５０の厚みの寸法は、後述する第２方向(Ｘ軸方向)における筒体１２０と拘束部１４０との間隔の寸法より小さい。金属板部１５０の厚みは、たとえば、１ｍｍである。 The metal plate portion 150 has a flat plate shape. The metal plate portion 150 is attached to the inner surface 111, which is the attachment surface of the exterior portion 110, and extends along the inner surface 111 of the exterior portion 110. In this embodiment, the metal plate portion 150 is attached within the recess 112. The metal plate portion 150 is made of an aluminum alloy such as duralumin containing aluminum, or a metal such as stainless steel. The thickness of the metal plate portion 150 is smaller than the distance between the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction), which will be described later. The thickness of the metal plate portion 150 is, for example, 1 mm.
　筒体１２０は、第１方向(Ｚ軸方向)から見て、金属板部１５０の中央部に取り付けられている。本実施形態においては、筒体１２０の第１方向(Ｚ軸方向)の一端が、金属板部１５０に接着されている。筒体１２０は、矩形環状の形状を有している。筒体１２０は、第３方向(Ｙ軸方向)に沿う長手方向を有し、第２方向(Ｘ軸方向)に沿う短手方向を有している。筒体１２０の軸方向は、第１方向(Ｚ軸方向)に沿っている。 The cylindrical body 120 is attached to the center portion of the metal plate portion 150 when viewed from the first direction (Z-axis direction). In this embodiment, one end of the cylindrical body 120 in the first direction (Z-axis direction) is bonded to the metal plate portion 150. The cylinder 120 has a rectangular annular shape. The cylinder 120 has a longitudinal direction along the third direction (Y-axis direction) and a lateral direction along the second direction (X-axis direction). The axial direction of the cylinder 120 is along the first direction (Z-axis direction).
　筒体１２０は、樹脂、ガラスエポキシまたは金属などから形成されている。超音波トランスデューサ１００の温度変化による特性変化を抑制する観点では、筒体１２０は金属で構成されていることが好ましい。一方、超音波トランスデューサ１００が送信または受信する超音波を低周波数化する観点、および、超音波トランスデューサ１００を小型化する観点では、筒体１２０は樹脂で構成されていることが好ましい。本実施形態においては、筒体１２０は、アルミニウムで構成されている。 The cylinder 120 is made of resin, glass epoxy, metal, or the like. From the viewpoint of suppressing changes in characteristics of the ultrasonic transducer 100 due to temperature changes, the cylindrical body 120 is preferably made of metal. On the other hand, from the viewpoint of lowering the frequency of the ultrasound transmitted or received by the ultrasound transducer 100 and from the viewpoint of downsizing the ultrasound transducer 100, the cylindrical body 120 is preferably made of resin. In this embodiment, the cylindrical body 120 is made of aluminum.
　図３は、本発明の実施形態１に係る超音波トランスデューサが備える超音波振動子の構成を示す断面図である。図１に示すように、超音波振動子１３０は、筒体１２０に取り付けられており、金属板部１５０に間隔をあけて対向する。具体的には、超音波振動子１３０は、筒体１２０の第１方向(Ｚ軸方向)の他端に取り付けられており、筒体１２０の内側空間を間に挟んで金属板部１５０と対向している。 FIG. 3 is a cross-sectional view showing the configuration of an ultrasonic transducer included in the ultrasonic transducer according to Embodiment 1 of the present invention. As shown in FIG. 1, the ultrasonic transducer 130 is attached to the cylindrical body 120, and faces the metal plate portion 150 with an interval therebetween. Specifically, the ultrasonic transducer 130 is attached to the other end of the cylinder 120 in the first direction (Z-axis direction), and faces the metal plate part 150 with the inner space of the cylinder 120 in between. are doing.
　図１～図３に示すように、超音波振動子１３０は、圧電体１３１を含む圧電素子である。図３に示すように、本実施形態においては、超音波振動子１３０は、積層された２つの圧電体１３１を含む。２つの圧電体１３１の分極方向Ｄｐは、互いに異なっている。具体的には、２つの圧電体１３１の分極方向Ｄｐは、第１方向(Ｚ軸方向)において互いに向かい合っている。２つの圧電体１３１は、第１電極１３２および第２電極１３３に挟まれており、２つの圧電体１３１の間に中間電極１３４が配置されている。第１電極１３２および第２電極１３３は交流電圧を印加可能な処理回路１０と電気的に接続されている。超音波振動子１３０は、いわゆる、シリーズ型のバイモルフ型圧電振動子である。２つの圧電体１３１の厚みの合計は、後述するメイン振動部およびサブ振動部の各々の横波の音速と超音波振動子１３０の横波の音速とを合わせる観点から、たとえば、１．０５ｍｍ以上１．９５ｍｍ以下である。 As shown in FIGS. 1 to 3, the ultrasonic transducer 130 is a piezoelectric element including a piezoelectric body 131. As shown in FIG. 3, in this embodiment, the ultrasonic transducer 130 includes two piezoelectric bodies 131 stacked together. The polarization directions Dp of the two piezoelectric bodies 131 are different from each other. Specifically, the polarization directions Dp of the two piezoelectric bodies 131 face each other in the first direction (Z-axis direction). The two piezoelectric bodies 131 are sandwiched between a first electrode 132 and a second electrode 133, and an intermediate electrode 134 is arranged between the two piezoelectric bodies 131. The first electrode 132 and the second electrode 133 are electrically connected to the processing circuit 10 to which an alternating current voltage can be applied. The ultrasonic transducer 130 is a so-called series bimorph piezoelectric transducer. The total thickness of the two piezoelectric bodies 131 is, for example, 1.05 mm or more, from the viewpoint of matching the sound speed of the transverse waves of the main vibrating section and the sub-vibrating section, which will be described later, with the sound velocity of the transverse waves of the ultrasonic vibrator 130. It is 95 mm or less.
　拘束部１４０は、第１方向(Ｚ軸方向)から見て、金属板部２５０の縁部に取り付けられている。拘束部１４０は、筒体１２０に一定の間隔をあけて筒体１２０を挟んでいる。本実施形態においては、拘束部１４０は、環状の形状を有している。具体的には、拘束部１４０は、矩形環状の形状を有している。拘束部１４０は、筒体１２０に間隔をあけつつ筒体１２０を外側から取り囲んでいる。ただし、拘束部１４０は、第２方向(Ｘ軸方向)において筒体１２０に一定の間隔をあけて筒体１２０を挟んでいればよい。拘束部１４０の第１方向(Ｚ軸方向)の一端が、金属板部１５０に接着されている。 The restraint part 140 is attached to the edge of the metal plate part 250 when viewed from the first direction (Z-axis direction). The restraint part 140 sandwiches the cylinder 120 with a constant interval between the cylinders 120. In this embodiment, the restraint part 140 has an annular shape. Specifically, the restraining portion 140 has a rectangular annular shape. The restraint part 140 surrounds the cylinder 120 from the outside while leaving an interval between the cylinders 120. However, the restraining portion 140 may sandwich the cylinder 120 at a constant interval in the second direction (X-axis direction). One end of the restraint section 140 in the first direction (Z-axis direction) is bonded to the metal plate section 150.
　拘束部１４０は、ステンレス鋼もしくはアルミニウムなどの金属、または、ガラスエポキシなどの剛性の高い材料で構成されている。金属板部１５０を間に挟んで拘束部１４０が取り付けられている部分の外装部１１０が拘束されることによって、後述するサブ振動部の振動をサブ振動部内に閉じ込めて安定させることができる。 The restraint part 140 is made of metal such as stainless steel or aluminum, or a highly rigid material such as glass epoxy. By restraining the portion of the exterior part 110 to which the restraining part 140 is attached with the metal plate part 150 in between, the vibrations of the sub-vibrating part, which will be described later, can be confined and stabilized within the sub-vibrating part.
　拘束部１４０の共振周波数が超音波振動子１３０の共振周波数に近い場合、超音波振動子１３０の共振に不要な振動が付加され、超音波トランスデューサ１００の出力特性および入力特性が低下する。図４は、拘束部が基本モードで共振している状態を第１方向から見た平面図である。図５は、拘束部が高次モードで共振している状態を第１方向から見た平面図である。本実施形態においては、図４に示す拘束部１４０の基本モードの共振周波数は、超音波振動子１３０の共振周波数に比較して２０％以上低い周波数である。図５に示す拘束部１４０の高次モードの共振周波数は、超音波振動子１３０の共振周波数に比較して２０％以上高い周波数である。 When the resonant frequency of the restraint part 140 is close to the resonant frequency of the ultrasonic transducer 130, unnecessary vibrations are added to the resonance of the ultrasonic transducer 130, and the output characteristics and input characteristics of the ultrasonic transducer 100 deteriorate. FIG. 4 is a plan view of a state in which the restraint section resonates in the fundamental mode, viewed from the first direction. FIG. 5 is a plan view of a state in which the restraint section resonates in a higher-order mode, as viewed from the first direction. In this embodiment, the resonance frequency of the fundamental mode of the restraint section 140 shown in FIG. 4 is lower than the resonance frequency of the ultrasonic transducer 130 by 20% or more. The high-order mode resonance frequency of the restraint section 140 shown in FIG. 5 is higher than the resonance frequency of the ultrasonic transducer 130 by 20% or more.
　図６は、本発明の実施形態１に係る超音波トランスデューサが超音波を送信または受信しているときの、有限要素法を用いてシミュレーション解析した変位状態を示す斜視図である。図７は、図６の超音波トランスデューサをＶＩＩ－ＶＩＩ線矢印方向から見た断面図である。シミュレーション解析条件として、凹部１１２が形成されている部分の外装部１１０の厚みを１ｍｍ、金属板部１５０の厚みを１ｍｍ、圧電体１３１の厚みを０．６ｍｍ、筒体１２０の外形の長手寸法を１６ｍｍ、短手寸法を６ｍｍ、筒体１２０の第１方向(Ｚ軸方向)の厚みを０．４ｍｍ、筒体１２０の第２方向(Ｘ軸方向)の幅を０．５ｍｍとした。すなわち、筒体１２０の内形の長手寸法を１５ｍｍ、短手寸法を５ｍｍとした。拘束部１４０の第２方向(Ｘ軸方向)の幅を２ｍｍ、拘束部１４０の第１方向(Ｚ軸方向)の厚みを３ｍｍとした。筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を４ｍｍとした。 FIG. 6 is a perspective view showing a displacement state simulated and analyzed using the finite element method when the ultrasonic transducer according to Embodiment 1 of the present invention is transmitting or receiving ultrasonic waves. FIG. 7 is a cross-sectional view of the ultrasonic transducer of FIG. 6 viewed from the direction of the arrow VII-VII. As simulation analysis conditions, the thickness of the exterior part 110 in the part where the recess 112 is formed is 1 mm, the thickness of the metal plate part 150 is 1 mm, the thickness of the piezoelectric body 131 is 0.6 mm, and the longitudinal dimension of the outer shape of the cylinder 120 is The width of the cylinder 120 in the first direction (Z-axis direction) was 0.4 mm, and the width of the cylinder 120 in the second direction (X-axis direction) was 0.5 mm. That is, the longitudinal dimension of the inner shape of the cylindrical body 120 was 15 mm, and the lateral dimension was 5 mm. The width of the restraint part 140 in the second direction (X-axis direction) was 2 mm, and the thickness of the restraint part 140 in the first direction (Z-axis direction) was 3 mm. The interval between the cylindrical body 120 and the restraint part 140 in the second direction (X-axis direction) was set to 4 mm.
　図６および図７に示すように、本発明の実施形態１に係る超音波トランスデューサ１００は、第１方向(Ｚ軸方向)から見て、外装部１１０および金属板部１５０における筒体１２０の内側に位置する部分であるメイン振動部１１０ｍ、および、第２方向(Ｘ軸方向)において外装部１１０および金属板部１５０における筒体１２０の外側かつ拘束部１４０の内側に位置する部分であるサブ振動部１１０ｓを有する。メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々は、外装部１１０において凹部１１２が形成されて薄くなっている部分と金属板部１５０とで構成されている。 As shown in FIGS. 6 and 7, the ultrasonic transducer 100 according to the first embodiment of the present invention has the inner side of the cylindrical body 120 in the exterior portion 110 and the metal plate portion 150 when viewed from the first direction (Z-axis direction). the main vibration part 110m, which is the part located in the second direction (X-axis direction), and the sub-vibration part, which is the part located outside the cylinder 120 and inside the restraint part 140 in the exterior part 110 and the metal plate part 150 in the second direction (X-axis direction) It has a section 110s. Each of the main vibrating section 110m and the sub-vibrating section 110s includes a thinned portion of the exterior section 110 in which a recess 112 is formed and a metal plate section 150.
　図７に示すように、メイン振動部１１０ｍは、超音波振動子１３０とは第１方向(Ｚ軸方向)において逆位相で共振振動する。すなわち、メイン振動部１１０ｍの共振振動Ｂｍの変位方向と、超音波振動子１３０の共振振動Ｂｐの変位方向とは、第１方向(Ｚ軸方向)において互いに反対向きである。 As shown in FIG. 7, the main vibrating section 110m resonates in an opposite phase to the ultrasonic vibrator 130 in the first direction (Z-axis direction). That is, the displacement direction of the resonance vibration Bm of the main vibration section 110m and the displacement direction of the resonance vibration Bp of the ultrasonic transducer 130 are opposite to each other in the first direction (Z-axis direction).
　サブ振動部１１０ｓは、メイン振動部１１０ｍとは第１方向(Ｚ軸方向)において逆位相で共振振動する。すなわち、サブ振動部１１０ｓの共振振動Ｂｓの変位方向と、メイン振動部１１０ｍの共振振動Ｂｍの変位方向とは、第１方向(Ｚ軸方向)において互いに反対向きである。 The sub-vibrating part 110s resonates in a phase opposite to that of the main vibrating part 110m in the first direction (Z-axis direction). That is, the displacement direction of the resonant vibration Bs of the sub-vibrating section 110s and the displacement direction of the resonant vibration Bm of the main vibrating section 110m are opposite to each other in the first direction (Z-axis direction).
　図７に示すように、メイン振動部１１０ｍが超音波振動子１３０とは第１方向(Ｚ軸方向)において逆位相で共振振動することにより、図６に示すように、外装部１１０におけるメイン振動部１１０ｍの周囲への振動漏れを小さくすることができる。これにより、超音波トランスデューサ１００の指向性の角度範囲を広く確保することができる。また、超音波トランスデューサ１００においては、サブ振動部１１０ｓにおいて上記の共振振動Ｂｓを励起させることによって、高音圧の超音波の送信および高感度の超音波の受信の少なくとも一方を実現しつつ超音波トランスデューサ１００の指向性の角度範囲を広く確保することができる。 As shown in FIG. 7, the main vibrating part 110m resonates in an opposite phase to the ultrasonic transducer 130 in the first direction (Z-axis direction), so that the main vibration in the exterior part 110 as shown in FIG. Vibration leakage to the surroundings of the portion 110m can be reduced. Thereby, a wide angular range of directivity of the ultrasonic transducer 100 can be ensured. In addition, in the ultrasonic transducer 100, by exciting the above-mentioned resonant vibration Bs in the sub-vibrating section 110s, the ultrasonic transducer can transmit at least one of high-sound-pressure ultrasonic waves and high-sensitivity ultrasonic wave reception. A wide angular range of 100 degrees of directivity can be secured.
　外装部１１０を構成するポリプロピレンなどの樹脂は、低温で硬く、高温で柔らかくなるため、ヤング率が温度によって大きく変化する。そのため、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々の共振周波数が温度によって変化する。 The resin such as polypropylene that constitutes the exterior portion 110 is hard at low temperatures and soft at high temperatures, so the Young's modulus changes greatly depending on the temperature. Therefore, the resonance frequency of each of the main vibrating section 110m and the sub-vibrating section 110s changes depending on the temperature.
　本発明の実施形態１に係る超音波トランスデューサ１００においては、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々が、温度によるヤング率の変化が外装部１１０より少ない金属板部１５０を含むことにより、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々の共振周波数の温度による変化を低減することができる。その結果、超音波トランスデューサ１００の温度特性を安定させることができる。なお、金属板部１５０を構成する材料のヤング率が大きいほど、金属板部１５０の厚みを薄くすることができる。たとえば、ポリプロピレンを主成分とする樹脂で構成されている、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚み１ｍｍに対して、アルミニウム合金で構成されている金属板部１５０の厚みは１ｍｍまで、ステンレス鋼で構成されている金属板部１５０の厚みは０．６ｍｍまで薄くすることが可能である。 In the ultrasonic transducer 100 according to the first embodiment of the present invention, each of the main vibrating section 110m and the sub-vibrating section 110s includes the metal plate section 150 whose Young's modulus changes with temperature less than the exterior section 110. Changes in the resonance frequency of each of the vibrating section 110m and the sub-vibrating section 110s due to temperature can be reduced. As a result, the temperature characteristics of the ultrasonic transducer 100 can be stabilized. Note that the greater the Young's modulus of the material constituting the metal plate portion 150, the thinner the metal plate portion 150 can be. For example, for a thickness of 1 mm of the exterior part 110 of the main vibrating part 110m and the sub-vibrating part 110s, which is made of a resin whose main component is polypropylene, a metal plate made of an aluminum alloy is used. The thickness of the portion 150 can be reduced to 1 mm, and the thickness of the metal plate portion 150 made of stainless steel can be reduced to 0.6 mm.
　また、本発明の実施形態１に係る超音波トランスデューサ１００においては、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する外装部１１０の厚みを薄くすることにより、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々の共振周波数の温度による変化を低減することができる。これによっても、超音波トランスデューサ１００の温度特性を安定させることができる。たとえば、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みは、金属板部１５０の厚みの２倍以下である。 Furthermore, in the ultrasonic transducer 100 according to the first embodiment of the present invention, the thickness of the exterior part 110 that constitutes each of the main vibrating part 110m and the sub-vibrating part 110s is reduced. Changes in each resonance frequency of 110s due to temperature can be reduced. This also makes it possible to stabilize the temperature characteristics of the ultrasonic transducer 100. For example, the thickness of the exterior portion 110 that constitutes each of the main vibrating portion 110m and the sub vibrating portion 110s is twice or less the thickness of the metal plate portion 150.
　ここで、メイン音源の両側に、メイン音源とは逆位相で振動するサブ音源を配置した場合のメイン音源とサブ音源との間の距離と指向性との関係について有限要素法を用いてシミュレーション解析した結果について説明する。 Here, we will conduct a simulation analysis using the finite element method to examine the relationship between the distance and directivity between the main sound source and the sub sound sources when sub sound sources that vibrate in an opposite phase to the main sound source are placed on both sides of the main sound source. The results will be explained below.
　図８は、メイン音源の両側に、メイン音源とは逆位相で振動するサブ音源を配置した状態を示す模式図である。図８に示すように、メイン音源ＭＳの両側に、メイン音源ＭＳとは逆位相で振動するサブ音源ＳＳを配置した簡素化したモデルを用いて、メイン音源ＭＳとサブ音源ＳＳとの間の距離Ｄをパラメータとして有限要素法を用いてシミュレーション解析した。メイン音源ＭＳとサブ音源ＳＳとの音圧比率は、９：１とした。メイン音源ＭＳおよびサブ音源ＳＳの各々の共振周波数は、５４ｋＨｚとした。 FIG. 8 is a schematic diagram showing a state in which sub sound sources that vibrate in an opposite phase to the main sound source are arranged on both sides of the main sound source. As shown in FIG. 8, using a simplified model in which sub sound sources SS vibrating in opposite phase to the main sound source MS are arranged on both sides of the main sound source MS, the distance between the main sound source MS and the sub sound source SS is A simulation analysis was performed using the finite element method with D as a parameter. The sound pressure ratio between the main sound source MS and the sub sound source SS was set to 9:1. The resonance frequency of each of the main sound source MS and sub sound source SS was 54 kHz.
　図９は、メイン音源とサブ音源との間の距離を４ｍｍ、６ｍｍおよび８ｍｍの３種類に変化させて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。図９においては、縦軸に、音圧レベル(ｄＢ)、円周軸に、メイン音源の中心からの放射角度(°)を示している。また、メイン音源ＭＳとサブ音源ＳＳとの間の距離Ｄが４ｍｍのときの指向性を実線、距離Ｄが６ｍｍのときの指向性を点線、距離Ｄが８ｍｍのときの指向性を１点鎖線で示している。なお、上記の３つのケースの各々において、放射角度θ＝０°の正面方向における音圧レベルを０ｄＢとして、放射角度θと音圧レベルとの推移を示している。 FIG. 9 is a graph showing the directivity obtained by simulation analysis using the finite element method while changing the distance between the main sound source and the sub sound source into three types: 4 mm, 6 mm, and 8 mm. In FIG. 9, the vertical axis shows the sound pressure level (dB), and the circumferential axis shows the radiation angle (°) from the center of the main sound source. Also, the solid line represents the directivity when the distance D between the main sound source MS and the sub sound source SS is 4 mm, the dotted line represents the directivity when the distance D is 6 mm, and the dot-dashed line represents the directivity when the distance D is 8 mm. It is shown in In addition, in each of the above three cases, the transition of the radiation angle θ and the sound pressure level is shown assuming that the sound pressure level in the front direction when the radiation angle θ=0° is 0 dB.
　図９に示すように、音圧レベルが－３ｄＢまで低下する放射角度の絶対値は、距離Ｄが４ｍｍのときは５４°、距離Ｄが６ｍｍのときは４７°、距離Ｄが８ｍｍのときは３８°であった。このように、メイン音源ＭＳとサブ音源ＳＳとの間の距離Ｄが短いほど、超音波トランスデューサの指向性の角度範囲が広くなる傾向が認められた。 As shown in Figure 9, the absolute value of the radiation angle at which the sound pressure level decreases to -3 dB is 54 degrees when the distance D is 4 mm, 47 degrees when the distance D is 6 mm, and 47 degrees when the distance D is 8 mm. It was 38°. Thus, it was observed that the shorter the distance D between the main sound source MS and the sub sound source SS, the wider the angular range of the directivity of the ultrasonic transducer.
　以下、本発明の一形態に係る超音波トランスデューサ１００が備える金属板部１５０について詳細に説明する。 Hereinafter, the metal plate portion 150 included in the ultrasonic transducer 100 according to one embodiment of the present invention will be described in detail.
　図１に示すように、本発明の一形態に係る超音波トランスデューサ１００においては、第１方向(Ｚ軸方向)から見て、金属板部１５０のサブ振動部１１０ｓとなる位置に、金属板部１５０を貫通しつつ第３方向(Ｙ軸方向)に延在するスリット１５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、スリット１５１の中心１５１ｃは、３５％以上の位置に配置されている。 As shown in FIG. 1, in an ultrasonic transducer 100 according to one embodiment of the present invention, a metal plate portion is provided at a position of a sub-vibration portion 110s of a metal plate portion 150 when viewed from the first direction (Z-axis direction). A slit 151 is formed that extends in the third direction (Y-axis direction) while penetrating through 150 . When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the slit 140 is taken as the 100% position, the center 151c of the slit 151 is arranged at a position of 35% or more.
　上記のように、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々が金属板部１５０を含むことにより超音波トランスデューサの温度特性を安定させることができる。超音波トランスデューサの温度特性をより安定させるためには、金属板部１５０が厚いことが好ましいが、金属板部１５０が厚くなるにしたがって、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々の共振周波数が高くなり、超音波トランスデューサの指向性の角度範囲が狭くなる。仮に、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々の振動領域の面積を大きくした場合、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々の共振周波数を下げることはできるが、超音波トランスデューサが大型化する。そこで、本実施形態に係る超音波トランスデューサ１００においては、金属板部１５０の所望の位置にスリット１５１を形成することにより、超音波トランスデューサ１００の指向性の角度範囲を広く確保しつつ超音波トランスデューサ１００を小型化している。 As described above, since each of the main vibrating section 110m and the sub-vibrating section 110s includes the metal plate section 150, the temperature characteristics of the ultrasonic transducer can be stabilized. In order to further stabilize the temperature characteristics of the ultrasonic transducer, it is preferable that the metal plate portion 150 is thick. However, as the metal plate portion 150 becomes thicker, the resonance frequency of each of the main vibrating portion 110m and the sub vibrating portion 110s increases. The angular range of directivity of the ultrasonic transducer becomes narrower. If the area of each vibration region of the main vibration section 110m and the sub-vibration section 110s is increased, the resonance frequency of each of the main vibration section 110m and the sub-vibration section 110s can be lowered, but the ultrasonic transducer becomes larger. do. Therefore, in the ultrasonic transducer 100 according to the present embodiment, by forming the slits 151 at desired positions of the metal plate portion 150, the ultrasonic transducer 100 can be is downsized.
　ここで、金属板部１５０に形成されたスリット１５１の中心１５１ｃの位置と、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率との関係について、有限要素法を用いてシミュレーション解析した結果について説明する。 Here, the relationship between the position of the center 151c of the slit 151 formed in the metal plate part 150 and the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is analyzed by simulation using the finite element method. The results will be explained below.
　図１０は、スリットの中心の位置と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。図１０においては、縦軸に、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率(％)、横軸に、スリットの中心の位置を示している。また、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサにおける、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率を、点線で示している。 FIG. 10 is a graph showing the relationship between the position of the center of the slit and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section. In FIG. 10, the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section, and the horizontal axis shows the position of the center of the slit. Further, in the ultrasonic transducer according to the comparative example in which the metal plate portion does not have a slit, the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section is indicated by a dotted line.
　シミュレーション解析条件のパラメータとして、図６および図７に示す共振モードの超音波トランスデューサにおいて、第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において、スリット１５１の中心１５１ｃを変位させた。図１に示すように、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において、筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置とした。 As a parameter for the simulation analysis conditions, in the resonance mode ultrasonic transducer shown in FIGS. 6 and 7, the second direction (X The center 151c of the slit 151 was displaced within the position range (in the axial direction). As shown in FIG. 1, in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, the outer edge of the cylinder 120 is at the 0% position, and the inner edge of the restraint part 140 is at the 0% position. The position was set at 100%.
　また、金属板部１５０の厚みを１ｍｍ、サブ振動部１１０ｓの振動領域の第２方向(Ｘ軸方向)の長さ、すなわち筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を４ｍｍ、スリット１５１の第２方向(Ｘ軸方向)における幅を０．５ｍｍとした。スリット１５１の中心１５１ｃの位置は、スリット１５１の第２方向(Ｘ軸方向)における幅の中央の位置である。 Further, the thickness of the metal plate portion 150 is 1 mm, and the length of the vibration region of the sub-vibration portion 110s in the second direction (X-axis direction), that is, the length of the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction). The interval was 4 mm, and the width of the slit 151 in the second direction (X-axis direction) was 0.5 mm. The center 151c of the slit 151 is located at the center of the width of the slit 151 in the second direction (X-axis direction).
　図１０に示すように、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率は、スリット１５１の中心１５１ｃが３４％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度または当該比率以下であったが、スリット１５１の中心１５１ｃが３５％以上の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度である比率を超えて急激に増加し、スリット１５１の中心１５１ｃが９４％の位置、すなわち、拘束部１４０の内縁の近傍の位置に到達するまで増加した。 As shown in FIG. 10, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that when the center 151c of the slit 151 is arranged at a position of 34% or less, the slit in the metal plate section is The ratio was the same as or lower than the ratio in the comparative example in which no slit was formed, but when the center 151c of the slit 151 was placed at a position of 35% or more, the comparison in which no slit was formed in the metal plate part The ratio rapidly increased beyond the same ratio as the ratio in the example, and increased until the center 151c of the slit 151 reached the 94% position, that is, the position near the inner edge of the restraint part 140.
　スリット１５１の中心１５１ｃが７８％以上の位置に配置されているとき、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率を２５％以上確保することができていた。 When the center 151c of the slit 151 was placed at a position of 78% or more, it was possible to ensure a ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m of 25% or more.
　スリット１５１の中心１５１ｃが拘束部１４０の内縁に近いほどサブ振動部１１０ｓの共振振幅が大きくなる理由は、サブ振動部１１０ｓは拘束部１４０の内縁の位置(１００％の位置)をノード点として共振振動するため、拘束部１４０の内縁の位置(１００％の位置)においてサブ振動部１１０ｓに生ずるせん断応力が最も大きくなり、スリット１５１が拘束部１４０の内縁の近くに位置するほど、上記せん断応力によるサブ振動部１１０ｓの変位が大きくなるからである。スリット１５１の中心１５１ｃが筒体１２０の外縁の近傍に位置するときにサブ振動部１１０ｓの共振振幅が小さくなる理由は、超音波振動子１３０の振動がスリット１５１によって緩和されてサブ振動部１１０ｓに伝わりにくくなるためである。 The reason why the resonance amplitude of the sub-vibrating part 110s becomes larger as the center 151c of the slit 151 is closer to the inner edge of the restraining part 140 is that the sub-vibrating part 110s resonates with the inner edge position (100% position) of the restraining part 140 as a node point. Because of the vibration, the shear stress generated in the sub-vibrating section 110s is greatest at the inner edge position (100% position) of the constraint section 140, and the closer the slit 151 is located to the inner edge of the constraint section 140, the greater the shear stress caused by the shear stress. This is because the displacement of the sub-vibrating section 110s becomes large. The reason why the resonance amplitude of the sub-vibrating part 110s becomes small when the center 151c of the slit 151 is located near the outer edge of the cylinder 120 is that the vibration of the ultrasonic transducer 130 is relaxed by the slit 151 and the resonance amplitude of the sub-vibrating part 110s is reduced. This is because it becomes difficult to convey.
　図１１は、図１０のデータから抽出した、スリットの中心が１９％の位置、６９％の位置または９４％の位置である３つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。図１１においては、縦軸に、音圧レベル(ｄＢ)、円周軸に、メイン振動部の中心からの放射角度(°)を示している。また、スリット１５１の中心１５１ｃが１９％の位置であるときの指向性を実線、スリット１５１の中心１５１ｃが６９％の位置であるときの指向性を点線、スリット１５１の中心１５１ｃが９４％の位置であるときの指向性を１点鎖線で示している。なお、上記の３つのケースの各々において、放射角度θ＝０°の正面方向における音圧レベルを０ｄＢとして、放射角度θと音圧レベルとの推移を示している。 Figure 11 shows the directivity extracted from the data in Figure 10 and analyzed by simulation using the finite element method for three cases in which the center of the slit is at the 19% position, 69% position, or 94% position. It is a graph. In FIG. 11, the vertical axis shows the sound pressure level (dB), and the circumferential axis shows the radiation angle (°) from the center of the main vibrating section. Also, the solid line indicates the directivity when the center 151c of the slit 151 is at the 19% position, the dotted line indicates the directivity when the center 151c of the slit 151 is at the 69% position, and the directivity when the center 151c of the slit 151 is at the 94% position. The directivity when this is the case is shown by a dashed line. In addition, in each of the above three cases, the transition of the radiation angle θ and the sound pressure level is shown assuming that the sound pressure level in the front direction when the radiation angle θ=0° is 0 dB.
　図１１に示すように、スリット１５１の中心１５１ｃが拘束部１４０の内縁の位置(１００％の位置)に近づくほど、指向性の角度範囲が広くなっていた。すなわち、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が大きくなるにしたがって、指向性の角度範囲が広くなっていた。 As shown in FIG. 11, the closer the center 151c of the slit 151 was to the inner edge position (100% position) of the restraint part 140, the wider the angular range of directivity became. That is, as the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m increases, the angular range of directivity becomes wider.
　次に、サブ振動部１１０ｓの共振周波数からメイン振動部１１０ｍの共振周波数を引いた差分と、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率との関係について、有限要素法を用いてシミュレーション解析した結果について説明する。 Next, the relationship between the difference obtained by subtracting the resonance frequency of the main vibration section 110m from the resonance frequency of the sub-vibration section 110s and the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is calculated using the finite element method. We will explain the results of simulation analysis using this method.
　図１２は、サブ振動部の共振周波数からメイン振動部の共振周波数を引いた差分と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。図１２においては、縦軸に、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率(％)、横軸に、サブ振動部の共振周波数からメイン振動部の共振周波数を引いた差分(ｋＨｚ)を示している。また、スリット１５１の中心１５１ｃが９４％の位置にある本実施形態に係る超音波トランスデューサのデータを実線、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサのデータを点線で示している。 FIG. 12 is a graph showing the relationship between the difference obtained by subtracting the resonance frequency of the main vibration section from the resonance frequency of the sub vibration section and the ratio of the resonance amplitude of the sub vibration section to the resonance amplitude of the main vibration section. In FIG. 12, the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating part to the resonance amplitude of the main vibrating part, and the horizontal axis shows the difference (%) obtained by subtracting the resonant frequency of the main vibrating part from the resonant frequency of the sub-vibrating part. kHz). Further, the data of the ultrasonic transducer according to the present embodiment in which the center 151c of the slit 151 is at the 94% position is shown as a solid line, and the data of the ultrasonic transducer according to the comparative example in which no slit is formed in the metal plate portion is shown as a dotted line. ing.
　図１１に示すように、スリット１５１の中心１５１ｃが９４％の位置にある本実施形態に係る超音波トランスデューサは、サブ振動部１１０ｓの共振周波数からメイン振動部１１０ｍの共振周波数を引いた差分が１０ｋＨｚ以上大きくなっても、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサよりもサブ振動部１１０ｓの共振振幅を大きく確保することができていた。 As shown in FIG. 11, in the ultrasonic transducer according to this embodiment in which the center 151c of the slit 151 is at the 94% position, the difference obtained by subtracting the resonance frequency of the main vibration section 110m from the resonance frequency of the sub-vibration section 110s is 10 kHz. Even with the above increase in size, the resonance amplitude of the sub-vibration section 110s was able to be ensured larger than that of the ultrasonic transducer according to the comparative example in which slits were not formed in the metal plate section.
　サブ振動部１１０ｓの共振周波数は、筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔によって変化する。図１３は、筒体と拘束部との間隔と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。図１３においては、縦軸に、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率(％)、横軸に、筒体と拘束部との間隔(ｍｍ)を示している。また、スリット１５１の中心１５１ｃが９４％の位置にある本実施形態に係る超音波トランスデューサのデータを実線、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサのデータを点線で示している。 The resonant frequency of the sub-vibrating section 110s changes depending on the distance between the cylindrical body 120 and the restraint section 140 in the second direction (X-axis direction). FIG. 13 is a graph showing the relationship between the distance between the cylinder and the restraint section and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section. In FIG. 13, the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating part to the resonance amplitude of the main vibrating part, and the horizontal axis shows the distance (mm) between the cylinder and the restraining part. Further, the data of the ultrasonic transducer according to the present embodiment in which the center 151c of the slit 151 is at the 94% position is shown as a solid line, and the data of the ultrasonic transducer according to the comparative example in which no slit is formed in the metal plate portion is shown as a dotted line. ing.
　図１３に示すように、スリット１５１の中心１５１ｃが９４％の位置にある本実施形態に係る超音波トランスデューサは、筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔が狭くなっても、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサよりもサブ振動部１１０ｓの共振振幅を大きく確保することができていた。たとえば、指向性の角度範囲を広く確保するために、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率を４０％にするには、筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を、本実施形態に係る超音波トランスデューサでは４ｍｍにすることができるが、比較例に係る超音波トランスデューサでは８ｍｍ以上にしなければならない。 As shown in FIG. 13, in the ultrasonic transducer according to the present embodiment in which the center 151c of the slit 151 is at the 94% position, the interval between the cylinder body 120 and the restraint part 140 in the second direction (X-axis direction) is narrow. Even so, the resonance amplitude of the sub-vibration section 110s was able to be ensured larger than that of the ultrasonic transducer according to the comparative example in which no slits were formed in the metal plate section. For example, in order to ensure a wide angular range of directivity and to set the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m to 40%, the second The interval in the direction (X-axis direction) can be set to 4 mm in the ultrasonic transducer according to the present embodiment, but must be set to 8 mm or more in the ultrasonic transducer according to the comparative example.
　よって、スリット１５１を拘束部１４０の内縁の近くに配置することにより、超音波トランスデューサ１００の指向性の角度範囲を広く確保しつつ超音波トランスデューサ１００を小型化することができる。 Therefore, by arranging the slit 151 near the inner edge of the restraining portion 140, the ultrasonic transducer 100 can be made smaller while ensuring a wide angular range of directivity of the ultrasonic transducer 100.
　また、筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を狭くすることにより、メイン振動部１１０ｍとサブ振動部１１０ｓとの間の距離が短くなるため、これによっても超音波トランスデューサ１００の指向性の角度範囲を広く確保することができる。 Furthermore, by narrowing the distance between the cylinder body 120 and the restraining part 140 in the second direction (X-axis direction), the distance between the main vibrating part 110m and the sub-vibrating part 110s is shortened. A wide angular range of directivity of the acoustic wave transducer 100 can be ensured.
　本実施形態においては、超音波振動子１３０は、いわゆる、シリーズ型のバイモルフ型圧電振動子であったが、超音波振動子１３０は、他の型の圧電振動子であってもよい。以下、本発明の実施形態１の変形例に係る超音波トランスデューサの超音波振動子について説明する。 In the present embodiment, the ultrasonic vibrator 130 is a so-called series bimorph piezoelectric vibrator, but the ultrasonic vibrator 130 may be another type of piezoelectric vibrator. Hereinafter, an ultrasonic vibrator of an ultrasonic transducer according to a modification of the first embodiment of the present invention will be described.
　図１４は、第１変形例に係る超音波振動子の構成を示す断面図である。図１４に示すように、第１変形例に係る超音波振動子１３０ａは、積層された２つの圧電体１３１を含む圧電素子である。２つの圧電体１３１の分極方向Ｄｐは、互いに等しい。超音波振動子１３０ａは、いわゆる、パラレル型のバイモルフ型圧電振動子である。 FIG. 14 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a first modification. As shown in FIG. 14, the ultrasonic transducer 130a according to the first modification is a piezoelectric element including two piezoelectric bodies 131 stacked together. The polarization directions Dp of the two piezoelectric bodies 131 are equal to each other. The ultrasonic transducer 130a is a so-called parallel bimorph piezoelectric transducer.
　第１変形例に係る超音波トランスデューサにおいては、２つの圧電体１３１の各々は、第１電極１３２および第２電極１３３に挟まれて交流電圧を印加可能に構成されている。第１電極１３２は、接地電位に固定されている。筒体１２０および拘束部１４０の各々は、金属で構成されており、第１電極１３２、筒体１２０、金属板部１５０および拘束部１４０は、機械的かつ電気的に互いに接続されて電磁シールドを構成している。 In the ultrasonic transducer according to the first modification, each of the two piezoelectric bodies 131 is configured to be sandwiched between a first electrode 132 and a second electrode 133 so that an alternating current voltage can be applied thereto. The first electrode 132 is fixed at ground potential. Each of the cylindrical body 120 and the restraint part 140 is made of metal, and the first electrode 132, the cylindrical body 120, the metal plate part 150, and the restraint part 140 are mechanically and electrically connected to each other to provide electromagnetic shielding. It consists of
　図１５は、第１変形例に係る超音波トランスデューサ、および、拘束部が絶縁材料で構成されている点のみ第１変形例に係る超音波トランスデューサとは異なる参考例に係る超音波トランスデューサの、各々における超音波振動子から生ずるノイズの大きさを示すグラフである。図１５に示すように、参考例に係る超音波トランスデューサのノイズの大きさが１９０ｍＶであったのに対して、第１変形例に係る超音波トランスデューサのノイズの大きさは１６５ｍＶであり、上記の電磁シールドを構成することによりノイズが低減できることが確認できた。 FIG. 15 shows an ultrasonic transducer according to a first modified example and an ultrasonic transducer according to a reference example that differs from the ultrasonic transducer according to the first modified example only in that the restraint part is made of an insulating material. 3 is a graph showing the magnitude of noise generated from an ultrasonic transducer in FIG. As shown in FIG. 15, the noise level of the ultrasonic transducer according to the reference example was 190 mV, while the noise level of the ultrasonic transducer according to the first modification example was 165 mV, and the above It was confirmed that noise could be reduced by configuring an electromagnetic shield.
　図１６は、第２変形例に係る超音波振動子の構成を示す断面図である。図１６に示すように、第２変形例に係る超音波振動子１３０ｂは、積層された４つの圧電体１３１を含む圧電素子である。４つの圧電体１３１のうち外側に位置する２つの圧電体１３１の分極方向Ｄｐは、第１方向(Ｚ軸方向)の一方を向いており、４つの圧電体１３１のうち内側に位置する２つの圧電体１３１の分極方向Ｄｐは、第１方向(Ｚ軸方向)の他方を向いている。超音波振動子１３０ｂは、いわゆる、マルチモルフ型圧電振動子である。 FIG. 16 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a second modification. As shown in FIG. 16, an ultrasonic transducer 130b according to the second modification is a piezoelectric element including four piezoelectric bodies 131 stacked together. The polarization direction Dp of the two piezoelectric bodies 131 located on the outside among the four piezoelectric bodies 131 is directed to one side of the first direction (Z-axis direction), and the polarization direction Dp of the two piezoelectric bodies 131 located on the inside of the four piezoelectric bodies 131 is The polarization direction Dp of the piezoelectric body 131 faces the other side of the first direction (Z-axis direction). The ultrasonic transducer 130b is a so-called multimorph piezoelectric transducer.
　図１７は、第３変形例に係る超音波振動子の構成を示す断面図である。図１７に示すように、第３変形例に係る超音波振動子１３０ｃは、１つの圧電体１３１を含む圧電素子である。具体的には、圧電体１３１は、第１電極１３２および金属からなる振動板１３５に挟まれている。超音波振動子１３０ｃは、いわゆる、ユニモルフ型圧電振動子である。 FIG. 17 is a cross-sectional view showing the configuration of an ultrasonic transducer according to a third modification. As shown in FIG. 17, an ultrasonic transducer 130c according to the third modification is a piezoelectric element including one piezoelectric body 131. Specifically, the piezoelectric body 131 is sandwiched between a first electrode 132 and a diaphragm 135 made of metal. The ultrasonic transducer 130c is a so-called unimorph piezoelectric transducer.
　図１８は、本発明の実施形態１の第４変形例に係る超音波トランスデューサの構成を示す縦断面図である。図１８に示すように、本発明の実施形態１の第４変形例に係る超音波トランスデューサ１００ａは、外装部１１０と、筒体１２０ａと、超音波振動子と、拘束部１４０と、金属板部１５０とを備える。筒体１２０ａは、有底筒状の形状を有している。筒体１２０ａは、金属で構成されている。筒体１２０ａの外側の底面に圧電体１３１が貼り付けられており、ユニモルフ型圧電振動子である超音波振動子が構成されている。 FIG. 18 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to a fourth modification of Embodiment 1 of the present invention. As shown in FIG. 18, an ultrasonic transducer 100a according to a fourth modification of Embodiment 1 of the present invention includes an exterior portion 110, a cylindrical body 120a, an ultrasonic transducer, a restraining portion 140, and a metal plate portion. 150. The cylinder 120a has a cylindrical shape with a bottom. The cylindrical body 120a is made of metal. A piezoelectric body 131 is attached to the outer bottom surface of the cylindrical body 120a, forming an ultrasonic transducer that is a unimorph piezoelectric transducer.
　図１９は、本発明の実施形態１の第５変形例に係る超音波トランスデューサの構成を示す縦断面図である。図１９に示すように、本発明の実施形態１の第５変形例に係る超音波トランスデューサ１００ｂは、外装部１１０と、筒体１２０と、超音波振動子１３０と、拘束部１４０と、金属板部１５０ｂとを備える。第１方向(Ｚ軸方向)から見て、金属板部１５０ｂのスリット１５１の一部は、拘束部１４０と重なっている。第１方向(Ｚ軸方向)から見て、金属板部１５０ｂのスリット１５１の幅の半分以上の一部が、拘束部１４０と重なっていてもよい。 FIG. 19 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to a fifth modification of Embodiment 1 of the present invention. As shown in FIG. 19, the ultrasonic transducer 100b according to the fifth modification of the first embodiment of the present invention includes an exterior portion 110, a cylinder 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate. 150b. When viewed from the first direction (Z-axis direction), a portion of the slit 151 of the metal plate portion 150b overlaps with the restraining portion 140. When viewed from the first direction (Z-axis direction), a portion of the metal plate portion 150b that is more than half the width of the slit 151 may overlap with the restraining portion 140.
　ここで、スリット１５１の延在長さと、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率との関係について、有限要素法を用いてシミュレーション解析した結果について説明する。図２０は、第１実施例に係る金属板部および拘束部を示す斜視図である。図２１は、第２実施例に係る金属板部および拘束部を示す斜視図である。図２２は、第３実施例に係る金属板部および拘束部を示す斜視図である。図２３は、第４実施例に係る金属板部および拘束部を示す斜視図である。 Here, the results of a simulation analysis using the finite element method regarding the relationship between the extension length of the slit 151 and the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m will be described. FIG. 20 is a perspective view showing a metal plate part and a restraint part according to the first embodiment. FIG. 21 is a perspective view showing a metal plate part and a restraint part according to the second embodiment. FIG. 22 is a perspective view showing a metal plate part and a restraint part according to the third embodiment. FIG. 23 is a perspective view showing a metal plate part and a restraining part according to the fourth embodiment.
　図２４は、超音波振動子の長さに対するスリットの延在長さの比率と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。図２４においては、縦軸に、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率(％)、横軸に、超音波振動子の長さに対するスリットの延在長さの比率(％)を示している。 FIG. 24 is a graph showing the relationship between the ratio of the extension length of the slit to the length of the ultrasonic transducer and the ratio of the resonance amplitude of the sub-vibration section to the resonance amplitude of the main vibration section. In FIG. 24, the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating part to the resonance amplitude of the main vibrating part, and the horizontal axis shows the ratio (%) of the extended length of the slit to the length of the ultrasonic transducer. ) is shown.
　シミュレーション解析条件として、筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を４．５ｍｍ、スリット１５１の第２方向(Ｘ軸方向)における幅を１ｍｍとし、スリット１５１の中心１５１ｃを８９％の位置に配置した。 As simulation analysis conditions, the interval between the cylinder 120 and the restraint part 140 in the second direction (X-axis direction) is 4.5 mm, the width of the slit 151 in the second direction (X-axis direction) is 1 mm, and the center of the slit 151 is 151c was placed at the 89% position.
　図２０に示すように、第１実施例に係る金属板部１５０ｃにおいては、第３方向(Ｙ軸方向)における中央部に長さが４ｍｍのスリット１５１が形成されている。図２１に示すように、第２実施例に係る金属板部１５０ｄにおいては、第３方向(Ｙ軸方向)における中央部から両端部に向かって長さが８ｍｍのスリット１５１が形成されている。図２２に示すように、第３実施例に係る金属板部１５０ｅにおいては、第３方向(Ｙ軸方向)における中央部から両端部に向かって長さが１２ｍｍのスリット1５１が形成されている。図２３に示すように、第４実施例に係る金属板部１５０ｆにおいては、第３方向(Ｙ軸方向)における中央部から両端部に向かって長さが１６ｍｍのスリット1５１が形成されている。 As shown in FIG. 20, in the metal plate portion 150c according to the first embodiment, a slit 151 having a length of 4 mm is formed in the center portion in the third direction (Y-axis direction). As shown in FIG. 21, in the metal plate portion 150d according to the second embodiment, a slit 151 having a length of 8 mm is formed from the center to both ends in the third direction (Y-axis direction). As shown in FIG. 22, in the metal plate portion 150e according to the third embodiment, a slit 151 having a length of 12 mm is formed from the center to both ends in the third direction (Y-axis direction). As shown in FIG. 23, in the metal plate portion 150f according to the fourth embodiment, a slit 151 having a length of 16 mm is formed from the center to both ends in the third direction (Y-axis direction).
　図２４に示すように、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率は、超音波振動子１３０の長さに対するスリット１５１の延在長さの比率が１５％以上８５％以下の範囲内で大きくなるにしたがって増加した。この解析結果から、超音波振動子１３０の長さに対するスリット１５１の延在長さの比率を調整することにより、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率を所望の値に変更できることが確認できた。 As shown in FIG. 24, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that the ratio of the extended length of the slit 151 to the length of the ultrasonic transducer 130 is 15% or more and 85%. It increased as the size increased within the following range. From this analysis result, by adjusting the ratio of the extension length of the slit 151 to the length of the ultrasonic transducer 130, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m can be set to a desired value. It was confirmed that it can be changed to
　ここで、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率と、超音波振動子１３０の単位変位当たりのサブ振動部１１０ｓに作用する第１方向(Ｚ軸方向)の応力およびサブ振動部１１０ｓの共振振幅の各々との関係について、有限要素法を用いてシミュレーション解析した結果について説明する。 Here, the ratio of the thickness of the metal plate part 150 to the thickness of the exterior part 110 of the parts constituting each of the main vibrating part 110m and the sub-vibrating part 110s, and the ratio of the thickness of the sub-vibrating part 110s per unit displacement of the ultrasonic vibrator 130. The relationship between the stress in the first direction (Z-axis direction) that acts and the resonance amplitude of the sub-vibrating section 110s will be explained using a simulation analysis using the finite element method.
　図２５は、メイン振動部およびサブ振動部の各々を構成する部分の外装部の厚みに対する金属板部の厚みの比率と、超音波振動子の単位変位当たりのサブ振動部に作用する第１方向の応力およびサブ振動部の共振振幅の各々との関係を示すグラフである。図２５においては、左側の縦軸に、サブ振動部の共振振幅(μｍ)、右側の縦軸に、超音波振動子の単位変位当たりのサブ振動部に作用する第１方向の応力(ＭＰａ／μｍ)、横軸に、メイン振動部およびサブ振動部の各々を構成する部分の外装部の厚みに対する金属板部の厚みの比率(％)を示している。また、サブ振動部の共振振幅を実線で示し、超音波振動子の単位変位当たりのサブ振動部に作用する第１方向の応力を点線で示している。 FIG. 25 shows the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part, and the first direction acting on the sub-vibrating part per unit displacement of the ultrasonic vibrator. 3 is a graph showing the relationship between the stress and the resonance amplitude of the sub-vibration section. In FIG. 25, the vertical axis on the left is the resonance amplitude (μm) of the sub-vibrating part, and the vertical axis on the right is the stress in the first direction acting on the sub-vibrating part per unit displacement of the ultrasonic transducer (MPa/ μm), and the horizontal axis represents the ratio (%) of the thickness of the metal plate portion to the thickness of the exterior portion of each of the main vibrating portion and the sub vibrating portion. Further, the resonance amplitude of the sub-vibrating section is shown by a solid line, and the stress in the first direction acting on the sub-vibrating section per unit displacement of the ultrasonic transducer is shown by a dotted line.
　シミュレーション解析条件として、ポリプロピレンを主成分とする樹脂で外装部１１０を構成し、アルミニウム合金で金属板部１５０を構成し、超音波振動子１３０を駆動する電圧の振幅を１Ｖとした。メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みを１ｍｍとした。 As simulation analysis conditions, the exterior part 110 was made of a resin whose main component was polypropylene, the metal plate part 150 was made of an aluminum alloy, and the amplitude of the voltage for driving the ultrasonic transducer 130 was 1V. The thickness of the exterior portion 110 of the portions constituting each of the main vibrating portion 110m and the sub vibrating portion 110s was 1 mm.
　図２５に示すように、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率が大きくなるにしたがって、超音波振動子１３０の単位変位当たりのサブ振動部１１０ｓに作用する第１方向(Ｚ軸方向)の応力は大きくなった。メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率が１６０％を超えると、超音波振動子１３０の単位変位当たりのサブ振動部１１０ｓに作用する第１方向(Ｚ軸方向)の応力が大きくなっているにも関わらず、サブ振動部１１０ｓ共振振幅は小さくなっていた。 As shown in FIG. 25, as the ratio of the thickness of the metal plate part 150 to the thickness of the exterior part 110 of the parts constituting each of the main vibrating part 110m and the sub-vibrating part 110s increases, the unit of the ultrasonic vibrator 130 increases. The stress in the first direction (Z-axis direction) acting on the sub-vibrating section 110s per displacement has increased. When the ratio of the thickness of the metal plate part 150 to the thickness of the exterior part 110 of the parts constituting each of the main vibrating part 110m and the sub-vibrating part 110s exceeds 160%, the sub-vibrating part per unit displacement of the ultrasonic vibrator 130 Although the stress in the first direction (Z-axis direction) acting on the sub-vibrating section 110s was increasing, the resonance amplitude of the sub-vibrating section 110s was small.
　ポリプロピレンを主成分とする樹脂で外装部１１０を構成し、アルミニウム合金で金属板部１５０を構成している場合、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率が１００％以上のとき、超音波トランスデューサ１００の温度特性を安定させることができる。上記のようにサブ振動部１１０ｓの共振振幅を大きくするとともに、超音波トランスデューサ１００の温度特性を安定させることも考慮すると、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率は、１００％以上１６０％以下であることが好ましい。 When the exterior part 110 is made of a resin whose main component is polypropylene, and the metal plate part 150 is made of an aluminum alloy, the thickness of the exterior part 110 in the parts that make up each of the main vibrating part 110m and the sub-vibrating part 110s. When the ratio of the thickness of the metal plate portion 150 to the thickness of the metal plate portion 150 is 100% or more, the temperature characteristics of the ultrasonic transducer 100 can be stabilized. Considering that the resonance amplitude of the sub-vibration section 110s is increased as described above and the temperature characteristics of the ultrasonic transducer 100 are stabilized, the exterior portion 110 of the portion constituting each of the main vibration section 110m and the sub-vibration section 110s The ratio of the thickness of the metal plate portion 150 to the thickness of the metal plate portion 150 is preferably 100% or more and 160% or less.
　超音波振動子１３０の質量に対する、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の質量の比率が大きくなるにしたがって、サブ振動部１１０ｓの変位は小さくなる。ステンレス鋼の密度は、アルミニウム合金の密度の約３倍である。そのため、金属板部１５０がステンレス鋼で構成されている場合、超音波振動子１３０の単位変位当たりのサブ振動部１１０ｓの変位が小さくなる。また、ステンレス鋼は、機械的Ｑ値が高いため、金属板部１５０がステンレス鋼で構成されている場合、サブ振動部１１０ｓの変位の帯域が狭くなるので、超音波振動子１３０の駆動周波数とサブ振動部１１０ｓの共振周波数とのずれに対して超音波トランスデューサ１００の特性変動が大きくなる。よって、超音波トランスデューサ１００の特性変動が大きくなることを抑制する観点から、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率は、１００％以下であることが好ましい。 As the ratio of the mass of the exterior part 110, which constitutes each of the main vibrating part 110m and the sub-vibrating part 110s, to the mass of the ultrasonic vibrator 130 increases, the displacement of the sub-vibrating part 110s becomes smaller. The density of stainless steel is approximately three times that of aluminum alloy. Therefore, when the metal plate part 150 is made of stainless steel, the displacement of the sub-vibrating part 110s per unit displacement of the ultrasonic vibrator 130 becomes small. Furthermore, since stainless steel has a high mechanical Q value, if the metal plate portion 150 is made of stainless steel, the displacement band of the sub-vibrating portion 110s becomes narrower, so that the driving frequency of the ultrasonic vibrator 130 The characteristic fluctuation of the ultrasonic transducer 100 becomes large with respect to the deviation from the resonant frequency of the sub-vibrating section 110s. Therefore, from the viewpoint of suppressing the characteristic fluctuations of the ultrasonic transducer 100 from increasing, the ratio of the thickness of the metal plate part 150 to the thickness of the exterior part 110 of the parts constituting each of the main vibrating part 110m and the sub-vibrating part 110s is as follows. , preferably 100% or less.
　ポリプロピレンを主成分とする樹脂で外装部１１０を構成し、ステンレス鋼で金属板部１５０を構成している場合、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率が６０％以上のとき、超音波トランスデューサ１００の温度特性を安定させることができる。上記のように超音波トランスデューサ１００の特性変動が大きくなることを抑制するとともに、超音波トランスデューサ１００の温度特性を安定させることも考慮すると、メイン振動部１１０ｍおよびサブ振動部１１０ｓの各々を構成する部分の外装部１１０の厚みに対する金属板部１５０の厚みの比率は、６０％以上１００％以下であることが好ましい。 When the exterior part 110 is made of resin whose main component is polypropylene, and the metal plate part 150 is made of stainless steel, the thickness of the exterior part 110 of the parts that make up each of the main vibrating part 110m and the sub-vibrating part 110s. When the ratio of the thickness of the metal plate portion 150 to the thickness of the metal plate portion 150 is 60% or more, the temperature characteristics of the ultrasonic transducer 100 can be stabilized. As described above, in order to suppress the characteristic fluctuations of the ultrasonic transducer 100 from increasing and to stabilize the temperature characteristics of the ultrasonic transducer 100, the parts constituting each of the main vibrating section 110m and the sub-vibrating section 110s are The ratio of the thickness of the metal plate portion 150 to the thickness of the exterior portion 110 is preferably 60% or more and 100% or less.
　図２６は、本発明の実施形態１の第６変形例に係る超音波トランスデューサが備える、金属板部、筒体および拘束部を示す縦断面図である。図２６に示すように、本発明の実施形態１の第６変形例に係る超音波トランスデューサが備える、金属板部１５０、筒体１２０および拘束部１４０は、鍛造などにより一体で形成されている。具体的には、拘束部１４０および金属板部１５０が、有底筒状の金属部材で構成されており、筒体１２０が当該金属部材の底部から突出している。本変形例においては、筒体１２０と金属板部１５０との界面からの振動漏れを抑制しつつ、金属板部１５０、筒体１２０および拘束部１４０からなるシールド構造によるシールド性を高めることができる。 FIG. 26 is a longitudinal sectional view showing a metal plate portion, a cylinder body, and a restraining portion included in an ultrasonic transducer according to a sixth modification of Embodiment 1 of the present invention. As shown in FIG. 26, the metal plate portion 150, the cylindrical body 120, and the restraining portion 140 included in the ultrasonic transducer according to the sixth modification of the first embodiment of the present invention are integrally formed by forging or the like. Specifically, the restraining portion 140 and the metal plate portion 150 are made of a cylindrical metal member with a bottom, and the cylinder 120 protrudes from the bottom of the metal member. In this modification, it is possible to suppress vibration leakage from the interface between the cylindrical body 120 and the metal plate part 150, and to improve shielding performance due to the shield structure consisting of the metal plate part 150, the cylindrical body 120, and the restraining part 140. .
　本発明の実施形態１に係る超音波トランスデューサ１００においては、第１方向(Ｚ軸方向)から見て、金属板部１５０のサブ振動部１１０ｓとなる位置に、金属板部１５０を貫通しつつ第３方向(Ｙ軸方向)に延在するスリット１５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、スリット１５１の中心１５１ｃは、３５％以上の位置に配置されている。これにより、超音波トランスデューサ１００の指向性の角度範囲を広く確保しつつ超音波トランスデューサ１００を小型化することができる。 In the ultrasonic transducer 100 according to the first embodiment of the present invention, when viewed from the first direction (Z-axis direction), the first vibration section 110s is located at a position of the sub-vibration section 110s of the metal plate section 150 while penetrating the metal plate section 150. A slit 151 extending in three directions (Y-axis direction) is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the slit 140 is taken as the 100% position, the center 151c of the slit 151 is arranged at a position of 35% or more. Thereby, the ultrasonic transducer 100 can be made smaller while ensuring a wide directional angular range of the ultrasonic transducer 100.
　本発明の実施形態１に係る超音波トランスデューサ１００においては、拘束部１４０は、環状の形状を有している。これにより、指向性の角度範囲を広げた第２方向(Ｘ軸方向)に直交する第３方向(Ｙ軸方向)に振動漏れが発生することを抑制することができる。 In the ultrasonic transducer 100 according to Embodiment 1 of the present invention, the restraining portion 140 has an annular shape. This makes it possible to suppress vibration leakage in the third direction (Y-axis direction) orthogonal to the second direction (X-axis direction) in which the angular range of directivity is expanded.
　本発明の実施形態１に係る超音波トランスデューサにおいては、超音波振動子１３０は、圧電体を含む圧電素子である。これにより、超音波トランスデューサ１００を簡易な構成にすることができる。 In the ultrasonic transducer according to Embodiment 1 of the present invention, the ultrasonic vibrator 130 is a piezoelectric element including a piezoelectric body. This allows the ultrasonic transducer 100 to have a simple configuration.
　本発明の実施形態１に係る超音波トランスデューサにおいては、サブ振動部１１０ｓの共振振幅は、メイン振動部１１０ｍの共振振幅より小さい。これにより、放射角度θ＝０°の正面方向における音圧レベルが低くなりすぎることを抑制できる。 In the ultrasonic transducer according to Embodiment 1 of the present invention, the resonance amplitude of the sub-vibrating section 110s is smaller than the resonance amplitude of the main vibrating section 110m. Thereby, the sound pressure level in the front direction at the radiation angle θ=0° can be prevented from becoming too low.
　(実施形態２)
　以下、本発明の実施形態２に係る超音波トランスデューサについて図を参照して説明する。本発明の実施形態２に係る超音波トランスデューサは、金属板部に貫通スリットの代わりに有底溝が形成されている点が本発明の実施形態１に係る超音波トランスデューサと異なるため、本発明の実施形態１に係る超音波トランスデューサと同様である構成については説明を繰り返さない。 (Embodiment 2)
Hereinafter, an ultrasonic transducer according to Embodiment 2 of the present invention will be described with reference to the drawings. The ultrasonic transducer according to Embodiment 2 of the present invention differs from the ultrasonic transducer according to Embodiment 1 of the present invention in that a bottomed groove is formed in the metal plate portion instead of a through slit. The description of the configuration similar to that of the ultrasonic transducer according to the first embodiment will not be repeated.
　図２７は、本発明の実施形態２に係る超音波トランスデューサの構成を示す縦断面図である。図２７に示すように、本発明の実施形態２に係る超音波トランスデューサ２００は、外装部１１０と、筒体１２０と、超音波振動子１３０と、拘束部１４０と、金属板部２５０とを備える。 FIG. 27 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to Embodiment 2 of the present invention. As shown in FIG. 27, an ultrasonic transducer 200 according to Embodiment 2 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 250. .
　金属板部２５０における外装部１１０側の第１面１Ｓとは反対の第２面２Ｓにおいて、第１方向(Ｚ軸方向)から見て金属板部２５０のサブ振動部１１０ｓとなる位置に、第３方向(Ｙ軸方向)に延在する第１有底溝２５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、第１有底溝２５１の中心２５１ｃは、２５％以上６０％以下の位置または８３％以上の位置に配置されている。本実施形態においては、第１有底溝２５１の深さの寸法は、金属板部２５０の厚みの寸法の半分である。 On a second surface 2S of the metal plate section 250 opposite to the first surface 1S on the side of the exterior section 110, a second vibration section 110s is provided at a position of the sub-vibration section 110s of the metal plate section 250 when viewed from the first direction (Z-axis direction). A first bottomed groove 251 extending in three directions (Y-axis direction) is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 251c of the first bottomed groove 251 is located at a position of 25% or more and 60% or less or 83% or more. In this embodiment, the depth of the first bottomed groove 251 is half the thickness of the metal plate portion 250.
　ここで、金属板部２５０に形成された第１有底溝２５１の中心２５１ｃの位置と、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率との関係について、有限要素法を用いてシミュレーション解析した結果について説明する。 Here, the relationship between the position of the center 251c of the first bottomed groove 251 formed in the metal plate part 250 and the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is determined using the finite element method. We will explain the results of simulation analysis using this method.
　図２８は、第１有底溝の中心の位置と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。図２８においては、縦軸に、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率(％)、横軸に、第１有底溝の中心の位置を示している。また、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサにおける、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率を、点線で示している。 FIG. 28 is a graph showing the relationship between the center position of the first bottomed groove and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section. In FIG. 28, the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section, and the horizontal axis shows the position of the center of the first bottomed groove. Further, in the ultrasonic transducer according to the comparative example in which the metal plate portion does not have a slit, the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section is indicated by a dotted line.
　シミュレーション解析条件のパラメータとして、図６および図７に示す共振モードの超音波トランスデューサにおいて、第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において、第１有底溝２５１の中心２５１ｃを変位させた。図２７に示すように、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において、筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置とした。 As a parameter for the simulation analysis conditions, in the resonance mode ultrasonic transducer shown in FIGS. 6 and 7, the second direction (X The center 251c of the first bottomed groove 251 was displaced within the position range (in the axial direction). As shown in FIG. 27, in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, the outer edge of the cylinder 120 is at the 0% position, and the inner edge of the restraint part 140 is at the 0% position. The position was set at 100%.
　また、金属板部２５０の厚みを１ｍｍ、サブ振動部１１０ｓの振動領域の第２方向(Ｘ軸方向)の長さ、すなわち筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を７ｍｍ、第１有底溝２５１の第２方向(Ｘ軸方向)における幅を０．５ｍｍとした。第１有底溝２５１の中心２５１ｃの位置は、第１有底溝２５１の第２方向(Ｘ軸方向)における幅の中央の位置である。 Further, the thickness of the metal plate portion 250 is 1 mm, and the length of the vibration region of the sub-vibrating portion 110s in the second direction (X-axis direction), that is, the length of the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction). The interval was 7 mm, and the width of the first bottomed groove 251 in the second direction (X-axis direction) was 0.5 mm. The position of the center 251c of the first bottomed groove 251 is the center position of the width of the first bottomed groove 251 in the second direction (X-axis direction).
　図２８に示すように、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率は、第１有底溝２５１の中心２５１ｃが２４％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度または当該比率以下であったが、第１有底溝２５１の中心２５１ｃが２５％以上６０％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度である比率を超えていた。メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率は、第１有底溝２５１の中心２５１ｃが６１％以上８２％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度であったが、第１有底溝２５１の中心２５１ｃが８３％以上の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度である比率を超えて急激に増加し、第１有底溝２５１の中心２５１ｃが９６％の位置、すなわち、拘束部１４０の内縁の近傍の位置に到達するまで増加した。 As shown in FIG. 28, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that when the center 251c of the first bottomed groove 251 is disposed at a position of 24% or less, the metal plate When the center 251c of the first bottomed groove 251 is placed at a position of 25% or more and 60% or less, The ratio exceeded the same ratio as that in the comparative example in which slits were not formed in the metal plate portion. The ratio of the resonance amplitude of the sub-vibration part 110s to the resonance amplitude of the main vibration part 110m is such that when the center 251c of the first bottomed groove 251 is located at a position of 61% or more and 82% or less, a slit is formed in the metal plate part. The ratio was the same as that in the comparative example in which no slit was formed, but when the center 251c of the first bottomed groove 251 was located at a position of 83% or more, the comparison in which no slit was formed in the metal plate part The ratio rapidly increased beyond the same ratio as the ratio in the example, and increased until the center 251c of the first bottomed groove 251 reached the 96% position, that is, the position near the inner edge of the restraint part 140. .
　第１有底溝２５１の中心２５１ｃが３２％以上４６％の位置または８９％以上の位置に配置されているとき、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率を２５％以上確保することができていた。 When the center 251c of the first bottomed groove 251 is located at a position of 32% or more and 46% or 89% or more, the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is set to 25%. We were able to secure more than that.
　第１有底溝２５１の中心２５１ｃが拘束部１４０の内縁の近傍に位置するときにサブ振動部１１０ｓの共振振幅が大きくなる理由は、サブ振動部１１０ｓは拘束部１４０の内縁の位置(１００％の位置)をノード点として共振振動するため、拘束部１４０の内縁の位置(１００％の位置)においてサブ振動部１１０ｓに生ずるせん断応力が最も大きくなり、第１有底溝２５１が拘束部１４０の内縁の近くに位置するほど、上記せん断応力によるサブ振動部１１０ｓの変位が大きくなるからである。第１有底溝２５１の中心２５１ｃが２５％以上６０％以下の位置に配置されているときにサブ振動部１１０ｓの共振振幅が大きくなる理由は、金属板部２５０の第２面２Ｓの２５％以上６０％以下の位置においてサブ振動部１１０ｓに共振振動時に生ずる引張応力が最も大きくなり、金属板部２５０の第２面２Ｓの２５％以上６０％以下の位置に第１有底溝２５１が形成されていることによってサブ振動部１１０ｓの第２方向(Ｘ軸方向)の剛性が小さくなってサブ振動部１１０ｓの変位が大きくなるからである。 The reason why the resonance amplitude of the sub-vibrating part 110s becomes large when the center 251c of the first bottomed groove 251 is located near the inner edge of the restraining part 140 is that the sub-vibrating part 110s is located near the inner edge of the restraining part 140 (100% The shear stress generated in the sub-vibrating part 110s is the largest at the inner edge position (100% position) of the restraint part 140, and the first bottomed groove 251 is the node point of the restraint part 140. This is because the closer the sub-vibrating portion 110s is located to the inner edge, the greater the displacement of the sub-vibrating portion 110s due to the shear stress. The reason why the resonance amplitude of the sub-vibrating part 110s becomes large when the center 251c of the first bottomed groove 251 is arranged at a position of 25% or more and 60% or less is that the 25% of the second surface 2S of the metal plate part 250 At a position above 60% or less, the tensile stress generated in the sub-vibrating part 110s during resonance vibration becomes the largest, and the first bottomed groove 251 is formed at a position between 25% and 60% of the second surface 2S of the metal plate part 250. This is because the rigidity of the sub-vibrating section 110s in the second direction (X-axis direction) becomes smaller due to this, and the displacement of the sub-vibrating section 110s becomes larger.
　第１有底溝２５１の中心２５１ｃが筒体１２０の外縁の近傍に位置するときにサブ振動部１１０ｓの共振振幅が小さくなる理由は、超音波振動子１３０の振動が第１有底溝２５１によって緩和されてサブ振動部１１０ｓに伝わりにくくなるためである。第１有底溝２５１の中心２５１ｃが６１％以上８２％以下の位置に配置されているときにサブ振動部１１０ｓの共振振幅が小さくなる理由は、金属板部２５０の第２面２Ｓの６１％以上８２％以下の位置においてサブ振動部１１０ｓに共振振動時に生ずる引張応力が比較的小さいため、６１％以上８２％以下の位置に第１有底溝２５１が形成されていることによるサブ振動部１１０ｓの変位を大きくする効果が少なくなるためである。 The reason why the resonance amplitude of the sub-vibrating section 110s becomes small when the center 251c of the first bottomed groove 251 is located near the outer edge of the cylinder 120 is that the vibration of the ultrasonic transducer 130 is caused by the first bottomed groove 251. This is because the vibration is relaxed and difficult to be transmitted to the sub-vibrating section 110s. The reason why the resonance amplitude of the sub-vibrating section 110s becomes small when the center 251c of the first bottomed groove 251 is arranged at a position of 61% or more and 82% or less is that the second surface 2S of the metal plate section 250 has a 61% Since the tensile stress generated in the sub-vibrating part 110s during resonance vibration is relatively small at the position of 82% or less, the sub-vibrating part 110s is formed by forming the first bottomed groove 251 at the position of 61% or more and 82% or less. This is because the effect of increasing the displacement of is reduced.
　図２９は、図２８のデータから抽出した、第１有底溝の中心が４％の位置、３９％の位置、７５％の位置または８９％の位置である４つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。図２９においては、縦軸に、音圧レベル(ｄＢ)、円周軸に、メイン振動部の中心からの放射角度(°)を示している。また、第１有底溝２５１の中心２５１ｃが４％の位置であるときの指向性を実線、第１有底溝２５１の中心２５１ｃが３９％の位置であるときの指向性を点線、第１有底溝２５１の中心２５１ｃが７５％の位置であるときの指向性を１点鎖線、第１有底溝２５１の中心２５１ｃが８９％の位置であるときの指向性を２点鎖線で示している。なお、上記の４つのケースの各々において、放射角度θ＝０°の正面方向における音圧レベルを０ｄＢとして、放射角度θと音圧レベルとの推移を示している。 Figure 29 shows the finite element method for four cases in which the center of the first bottomed groove is at the 4% position, 39% position, 75% position, or 89% position, extracted from the data in Figure 28. 3 is a graph showing directivity obtained by simulation analysis using In FIG. 29, the vertical axis shows the sound pressure level (dB), and the circumferential axis shows the radiation angle (°) from the center of the main vibrating section. Further, the solid line indicates the directivity when the center 251c of the first bottomed groove 251 is at the 4% position, the dotted line indicates the directivity when the center 251c of the first bottomed groove 251 is at the 39% position, and the The directivity when the center 251c of the bottomed groove 251 is at the 75% position is shown by the one-dot chain line, and the directivity when the center 251c of the first bottomed groove 251 is at the 89% position is shown by the two-dot chain line. There is. In addition, in each of the above four cases, the transition of the radiation angle θ and the sound pressure level is shown assuming that the sound pressure level in the front direction when the radiation angle θ=0° is 0 dB.
　図２９に示すように、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が比較的大きかった、第１有底溝２５１の中心２５１ｃが３９％または８９％の位置にあるときは、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が比較的小さかった、第１有底溝２５１の中心２５１ｃが４％または７５％の位置にあるときに比べて、指向性の角度範囲が広くなっていた。すなわち、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が大きくなるにしたがって、指向性の角度範囲が広くなっていた。 As shown in FIG. 29, when the center 251c of the first bottomed groove 251 is at the 39% or 89% position, the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is relatively large. compared to when the center 251c of the first bottomed groove 251 is at the 4% or 75% position, where the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is relatively small. The range of sexual angles was widening. That is, as the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m increases, the angular range of directivity becomes wider.
　本発明の実施形態２に係る超音波トランスデューサ２００においては、第１方向(Ｚ軸方向)から見て、金属板部２５０のサブ振動部１１０ｓとなる位置に、第３方向(Ｙ軸方向)に延在する第１有底溝２５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、第１有底溝２５１の中心２５１ｃは、２５％以上６０％以下の位置または８３％以上の位置に配置されている。これにより、超音波トランスデューサ２００の指向性の角度範囲を広く確保しつつ超音波トランスデューサ２００を小型化することができる。 In the ultrasonic transducer 200 according to the second embodiment of the present invention, when viewed from the first direction (Z-axis direction), the sub-vibration section 110s of the metal plate section 250 has a An extending first bottomed groove 251 is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 251c of the first bottomed groove 251 is located at a position of 25% or more and 60% or less or 83% or more. Thereby, the ultrasonic transducer 200 can be made smaller while ensuring a wide directional angular range of the ultrasonic transducer 200.
　図３０は、本発明の実施形態２に係る超音波トランスデューサにおいて金属板部と拘束部とによって形成された内部空間がダンピング材で埋められた状態を示す断面図である。図３０に示すように、本発明の実施形態２に係る超音波トランスデューサ２００においては、金属板部２５０と拘束部１４０とによって形成された内部空間が、シリコーンなどのダンピング材２６０によって埋められた場合でも、第１有底溝２５１が金属板部２５０を貫通していないため、ダンピング材２６０が金属板部２５０の第１面１Ｓに漏れ出ることがない。そのため、金属板部２５０に、筒体１２０、超音波振動子１３０および拘束部１４０を取り付けてダンピング材２６０で封止したユニットを、外装部１１０の内面１１１に取り付ける場合に、金属板部２５０と外装部１１０の内面１１１との間にダンピング材２６０が入り込むことにより生ずる上記ユニットの外装部１１０への取り付け不良を防止することができる。 FIG. 30 is a sectional view showing a state in which the internal space formed by the metal plate part and the restraining part is filled with a damping material in the ultrasonic transducer according to Embodiment 2 of the present invention. As shown in FIG. 30, in the ultrasonic transducer 200 according to the second embodiment of the present invention, when the internal space formed by the metal plate part 250 and the restraining part 140 is filled with a damping material 260 such as silicone, However, since the first bottomed groove 251 does not penetrate the metal plate portion 250, the damping material 260 does not leak to the first surface 1S of the metal plate portion 250. Therefore, when attaching a unit in which the cylindrical body 120, the ultrasonic transducer 130, and the restraining part 140 are attached to the metal plate part 250 and sealed with the damping material 260 to the inner surface 111 of the exterior part 110, the metal plate part 250 and It is possible to prevent the unit from being improperly attached to the exterior portion 110 due to the damping material 260 entering between the inner surface 111 of the exterior portion 110 and the damping material 260 .
　なお、ダンピング材２６０のヤング率は、たとえば、０．１ＭＰａ以上１００ＭＰａ以下である。外装部側とは反対側への不要な超音波の放射を抑制する観点では、ダンピング材２６０のヤング率は０．１ＭＰａ以上０．５ＭＰａ以下であることが好ましく、残響を抑制する観点では、ダンピング材２６０のヤング率は１０ＭＰａ以上５０ＭＰａ以下であることが好ましい。 Note that the Young's modulus of the damping material 260 is, for example, 0.1 MPa or more and 100 MPa or less. From the viewpoint of suppressing the emission of unnecessary ultrasonic waves to the side opposite to the exterior side, the Young's modulus of the damping material 260 is preferably 0.1 MPa or more and 0.5 MPa or less, and from the viewpoint of suppressing reverberation, the damping material 260 The Young's modulus of the material 260 is preferably 10 MPa or more and 50 MPa or less.
　(実施形態３)
　以下、本発明の実施形態３に係る超音波トランスデューサについて図を参照して説明する。本発明の実施形態３に係る超音波トランスデューサは、金属板部の第１面に有底溝が形成されている点が本発明の実施形態２に係る超音波トランスデューサと異なるため、本発明の実施形態２に係る超音波トランスデューサと同様である構成については説明を繰り返さない。 (Embodiment 3)
Hereinafter, an ultrasonic transducer according to Embodiment 3 of the present invention will be described with reference to the drawings. The ultrasonic transducer according to Embodiment 3 of the present invention differs from the ultrasonic transducer according to Embodiment 2 of the present invention in that a bottomed groove is formed on the first surface of the metal plate portion. The description of the configuration similar to that of the ultrasonic transducer according to the second embodiment will not be repeated.
　図３１は、本発明の実施形態３に係る超音波トランスデューサの構成を示す縦断面図である。図３１に示すように、本発明の実施形態３に係る超音波トランスデューサ３００は、外装部１１０と、筒体１２０と、超音波振動子１３０と、拘束部１４０と、金属板部３５０とを備える。 FIG. 31 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 3 of the present invention. As shown in FIG. 31, an ultrasonic transducer 300 according to Embodiment 3 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 350. .
　金属板部３５０における外装部１１０側の第１面１Ｓにおいて、第１方向(Ｚ軸方向)から見て金属板部３５０のサブ振動部１１０ｓとなる位置に、第３方向(Ｙ軸方向)に延在する第２有底溝３５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、第２有底溝３５１の中心３５１ｃは、１６％以上７６％以下の位置または９４％以上の位置に配置されている。本実施形態においては、第２有底溝３５１の深さの寸法は、金属板部３５０の厚みの寸法の半分である。 On the first surface 1S of the metal plate part 350 on the side of the exterior part 110, in the third direction (Y-axis direction) at a position that becomes the sub-vibrating part 110s of the metal plate part 350 when viewed from the first direction (Z-axis direction). An extending second bottomed groove 351 is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less or a position of 94% or more. In this embodiment, the depth of the second bottomed groove 351 is half the thickness of the metal plate portion 350.
　ここで、金属板部３５０に形成された第２有底溝３５１の中心３５１ｃの位置と、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率との関係について、有限要素法を用いてシミュレーション解析した結果について説明する。 Here, the relationship between the position of the center 351c of the second bottomed groove 351 formed in the metal plate part 350 and the ratio of the resonance amplitude of the sub-vibrating part 110s to the resonance amplitude of the main vibrating part 110m is determined using the finite element method. We will explain the results of simulation analysis using this method.
　図３２は、第２有底溝の中心の位置と、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率との関係を示すグラフである。図３２においては、縦軸に、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率(％)、横軸に、第２有底溝の中心の位置を示している。また、金属板部にスリットが形成されていない比較例に係る超音波トランスデューサにおける、メイン振動部の共振振幅に対するサブ振動部の共振振幅の比率を、点線で示している。 FIG. 32 is a graph showing the relationship between the center position of the second bottomed groove and the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section. In FIG. 32, the vertical axis shows the ratio (%) of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section, and the horizontal axis shows the position of the center of the second bottomed groove. Further, in the ultrasonic transducer according to the comparative example in which the metal plate portion does not have a slit, the ratio of the resonance amplitude of the sub-vibrating section to the resonance amplitude of the main vibrating section is indicated by a dotted line.
　シミュレーション解析条件のパラメータとして、図６および図７に示す共振モードの超音波トランスデューサにおいて、第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において、第２有底溝３５１の中心３５１ｃを変位させた。図３１に示すように、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において、筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置とした。 As a parameter for the simulation analysis conditions, in the resonance mode ultrasonic transducer shown in FIGS. 6 and 7, the second direction (X The center 351c of the second bottomed groove 351 was displaced within the position range (in the axial direction). As shown in FIG. 31, in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, the outer edge of the cylinder 120 is at the 0% position, and the inner edge of the restraint part 140 is at the 0% position. The position was set at 100%.
　また、金属板部３５０の厚みを１ｍｍ、サブ振動部１１０ｓの振動領域の第２方向(Ｘ軸方向)の長さ、すなわち筒体１２０と拘束部１４０との第２方向(Ｘ軸方向)における間隔を７ｍｍ、第２有底溝３５１の第２方向(Ｘ軸方向)における幅を０．５ｍｍとした。第２有底溝３５１の中心３５１ｃの位置は、第２有底溝３５１の第２方向(Ｘ軸方向)における幅の中央の位置である。 Further, the thickness of the metal plate portion 350 is 1 mm, and the length of the vibration region of the sub-vibrating portion 110s in the second direction (X-axis direction), that is, the length of the cylindrical body 120 and the restraining portion 140 in the second direction (X-axis direction). The interval was 7 mm, and the width of the second bottomed groove 351 in the second direction (X-axis direction) was 0.5 mm. The position of the center 351c of the second bottomed groove 351 is the center position of the width of the second bottomed groove 351 in the second direction (X-axis direction).
　図３２に示すように、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率は、第２有底溝３５１の中心３５１ｃが１５％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度または当該比率以下であったが、第２有底溝３５１の中心３５１ｃが１６％以上７６％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度である比率を超えていた。メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率は、第２有底溝３５１の中心３５１ｃが７７％以上９３％以下の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度であったが、第２有底溝３５１の中心３５１ｃが９４％以上の位置に配置されているとき、金属板部にスリットが形成されていない比較例における当該比率と同程度である比率を超えていた。 As shown in FIG. 32, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is such that when the center 351c of the second bottomed groove 351 is disposed at a position of 15% or less, the metal plate When the center 351c of the second bottomed groove 351 is located at a position of 16% or more and 76% or less, The ratio exceeded the same ratio as that in the comparative example in which slits were not formed in the metal plate portion. The ratio of the resonance amplitude of the sub-vibration part 110s to the resonance amplitude of the main vibration part 110m is such that when the center 351c of the second bottomed groove 351 is located at a position of 77% or more and 93% or less, a slit is formed in the metal plate part. The ratio was similar to that in the comparative example in which no slit was formed, but when the center 351c of the second bottomed groove 351 was located at a position of 94% or more, the comparison in which no slit was formed in the metal plate part It exceeded a ratio that is comparable to the ratio in the example.
　第２有底溝３５１の中心３５１ｃが２１％以上６８％以下の位置に配置されているとき、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率を２５％以上確保することができていた。 When the center 351c of the second bottomed groove 351 is arranged at a position of 21% or more and 68% or less, it is possible to ensure a ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m of 25% or more. It was done.
　第２有底溝３５１の中心３５１ｃが拘束部１４０の内縁の近傍に位置するときにサブ振動部１１０ｓの共振振幅が大きくなる理由は、サブ振動部１１０ｓは拘束部１４０の内縁の位置(１００％の位置)をノード点として共振振動するため、拘束部１４０の内縁の位置(１００％の位置)においてサブ振動部１１０ｓに生ずるせん断応力が最も大きくなり、第２有底溝３５１が拘束部１４０の内縁の近くに位置するほど、上記せん断応力によるサブ振動部１１０ｓの変位が大きくなるからである。ただし、第２有底溝３５１は金属板部３５０の第１面１Ｓに形成されているため、実施形態２に係る金属板部２５０の第２面２Ｓに形成されている第１有底溝２５１に比較して、上記せん断応力によるサブ振動部１１０ｓの変位を大きくする効果が少なくなっている。 The reason why the resonance amplitude of the sub-vibrating part 110s becomes large when the center 351c of the second bottomed groove 351 is located near the inner edge of the restraint part 140 is that the sub-vibrating part 110s is located at the inner edge of the restraint part 140 (100% The shear stress generated in the sub-vibrating part 110s is the largest at the inner edge position (100% position) of the restraint part 140, and the second bottomed groove 351 is the node point of the restraint part 140. This is because the closer the sub-vibrating portion 110s is located to the inner edge, the greater the displacement of the sub-vibrating portion 110s due to the shear stress. However, since the second bottomed groove 351 is formed on the first surface 1S of the metal plate part 350, the first bottomed groove 251 formed on the second surface 2S of the metal plate part 250 according to the second embodiment Compared to this, the effect of increasing the displacement of the sub-vibrating section 110s due to the shear stress is reduced.
　第２有底溝３５１の中心３５１ｃが１６％以上７６％以下の位置に配置されているときにサブ振動部１１０ｓの共振振幅が大きくなる理由は、金属板部３５０の第１面１Ｓの１６％以上７６％以下の位置においてサブ振動部１１０ｓに共振振動時に生ずる引張応力が最も大きくなり、１６％以上７６％以下の位置に第２有底溝３５１が形成されていることによってサブ振動部１１０ｓの第２方向(Ｘ軸方向)の剛性が小さくなってサブ振動部１１０ｓの変位が大きくなるからである。 The reason why the resonance amplitude of the sub-vibrating section 110s becomes large when the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less is that the 16% of the first surface 1S of the metal plate section 350 At a position above 76% or less, the tensile stress generated in the sub-vibrating part 110s during resonance vibration becomes the largest, and by forming the second bottomed groove 351 at a position between 16% and 76%, This is because the rigidity in the second direction (X-axis direction) becomes smaller and the displacement of the sub-vibrating section 110s becomes larger.
　第２有底溝３５１の中心３５１ｃが筒体１２０の外縁の近傍に位置するときにサブ振動部１１０ｓの共振振幅が小さくなる理由は、超音波振動子１３０の振動が第２有底溝３５１によって緩和されてサブ振動部１１０ｓに伝わりにくくなるためである。第２有底溝３５１の中心３５１ｃが７７％以上９３％以下の位置に配置されているときにサブ振動部１１０ｓの共振振幅が小さくなる理由は、金属板部３５０の第１面１Ｓの７７％以上９３％以下の位置においてサブ振動部１１０ｓに共振振動時に生ずる引張応力が比較的小さいため、７７％以上９３％以下の位置に第２有底溝３５１が形成されていることによるサブ振動部１１０ｓの変位を大きくする効果が少なくなるためである。 The reason why the resonance amplitude of the sub-vibrating section 110s becomes small when the center 351c of the second bottomed groove 351 is located near the outer edge of the cylinder 120 is that the vibration of the ultrasonic transducer 130 is caused by the second bottomed groove 351. This is because the vibration is relaxed and is less likely to be transmitted to the sub-vibrating section 110s. The reason why the resonance amplitude of the sub-vibrating part 110s becomes small when the center 351c of the second bottomed groove 351 is arranged at a position of 77% or more and 93% or less is that the 77% of the first surface 1S of the metal plate part 350 Since the tensile stress generated in the sub-vibrating part 110s during resonance vibration is relatively small at the position of 93% or less, the second bottomed groove 351 is formed at the position of 77% or more and 93% or less. This is because the effect of increasing the displacement of is reduced.
　図３３は、第２有底溝の中心が４％の位置、４６％の位置、８２％の位置または９６％の位置である４つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。図２８においては、縦軸に、音圧レベル(ｄＢ)、円周軸に、メイン振動部の中心からの放射角度(°)を示している。また、第２有底溝３５１の中心３５１ｃが４％の位置であるときの指向性を実線、第２有底溝３５１の中心３５１ｃが４６％の位置であるときの指向性を点線、第２有底溝３５１の中心３５１ｃが８２％の位置であるときの指向性を１点鎖線、第２有底溝３５１の中心３５１ｃが９６％の位置であるときの指向性を２点鎖線で示している。なお、上記の４つのケースの各々において、放射角度θ＝０°の正面方向における音圧レベルを０ｄＢとして、放射角度θと音圧レベルとの推移を示している。 Figure 33 shows the directivity analyzed by simulation using the finite element method for four cases in which the center of the second bottomed groove is at the 4% position, 46% position, 82% position, or 96% position. This is a graph showing. In FIG. 28, the vertical axis shows the sound pressure level (dB), and the circumferential axis shows the radiation angle (°) from the center of the main vibrating section. In addition, the solid line represents the directivity when the center 351c of the second bottomed groove 351 is at the 4% position, the dotted line represents the directivity when the center 351c of the second bottomed groove 351 is at the 46% position, and the second The directivity when the center 351c of the bottomed groove 351 is at the 82% position is shown by the one-dot chain line, and the directivity when the center 351c of the second bottomed groove 351 is at the 96% position is shown by the two-dot chain line. There is. In addition, in each of the above four cases, the transition of the radiation angle θ and the sound pressure level is shown assuming that the sound pressure level in the front direction when the radiation angle θ=0° is 0 dB.
　図３３に示すように、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が比較的大きかった、第２有底溝３５１の中心３５１ｃが４６％または９６％の位置にあるときは、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が比較的小さかった、第２有底溝３５１の中心３５１ｃが４％または８２％の位置にあるときに比べて、指向性の角度範囲が広くなっていた。すなわち、メイン振動部１１０ｍの共振振幅に対するサブ振動部１１０ｓの共振振幅の比率が大きくなるにしたがって、指向性の角度範囲が広くなっていた。 As shown in FIG. 33, when the center 351c of the second bottomed groove 351 is at the 46% or 96% position, the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m is relatively large. compared to when the center 351c of the second bottomed groove 351 is at the 4% or 82% position, where the ratio of the resonance amplitude of the sub-vibration section 110s to the resonance amplitude of the main vibration section 110m is relatively small. The range of sexual angles was widening. That is, as the ratio of the resonance amplitude of the sub-vibrating section 110s to the resonance amplitude of the main vibrating section 110m increases, the angular range of directivity becomes wider.
　本発明の実施形態３に係る超音波トランスデューサ３００においては、第１方向(Ｚ軸方向)から見て、金属板部３５０のサブ振動部１１０ｓとなる位置に、第３方向(Ｙ軸方向)に延在する第２有底溝３５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、第２有底溝３５１の中心３５１ｃは、１６％以上７６％以下の位置または９４％以上の位置に配置されている。これにより、超音波トランスデューサ３００の指向性の角度範囲を広く確保しつつ超音波トランスデューサ３００を小型化することができる。 In the ultrasonic transducer 300 according to the third embodiment of the present invention, when viewed from the first direction (Z-axis direction), the sub-vibration section 110s of the metal plate section 350 has a An extending second bottomed groove 351 is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less or a position of 94% or more. Thereby, the ultrasonic transducer 300 can be made smaller while ensuring a wide directional angular range of the ultrasonic transducer 300.
　ここで、サブ振動部１１０ｓの共振振動時に金属板部の４６％の位置に生ずる第２方向(Ｘ軸方向)の応力の第１方向(Ｚ軸方向)における分布について有限要素法を用いてシミュレーション解析した結果について説明する。シミュレーション解析条件として、凹部１１２が形成されている部分の外装部１１０の厚みを１ｍｍ、金属板部の厚みを１ｍｍ、外装部１１０の材質をポリプロピレン、金属板部の材質をアルミニウム合金とした。 Here, the distribution in the first direction (Z-axis direction) of the stress in the second direction (X-axis direction) that occurs at 46% of the metal plate portion during resonance vibration of the sub-vibration section 110s is simulated using the finite element method. The results of the analysis will be explained. As simulation analysis conditions, the thickness of the exterior part 110 in the part where the recess 112 is formed was 1 mm, the thickness of the metal plate part was 1 mm, the material of the exterior part 110 was polypropylene, and the material of the metal plate part was an aluminum alloy.
　図３４は、第１方向における第２面からの位置と、サブ振動部の共振振動時に金属板部の４６％の位置に生ずる第２方向の応力との関係を示すグラフである。図３４においては、縦軸に、サブ振動部の共振振動時に金属板部の４６％の位置に生ずる第２方向の応力(ｋＰａ)、横軸に、第１方向における第２面からの位置(ｍｍ)を示している。 FIG. 34 is a graph showing the relationship between the position from the second surface in the first direction and the stress in the second direction that occurs at a 46% position of the metal plate part during resonance vibration of the sub-vibrating part. In FIG. 34, the vertical axis shows the stress (kPa) in the second direction that occurs at the 46% position of the metal plate part during resonance vibration of the sub-vibrating part, and the horizontal axis shows the position (kPa) in the first direction from the second surface. mm) is shown.
　第１方向(Ｚ軸方向)における第２面２Ｓからの位置が０ｍｍ以上１ｍｍ以下の範囲における第２方向(Ｘ軸方向)の応力Ｌａは、金属板部に生じた応力である。第１方向(Ｚ軸方向)における第２面２Ｓからの位置が１ｍｍ超２ｍｍ以下の範囲における第２方向(Ｘ軸方向)の応力Ｌｂは、外装部１１０に生じた応力である。上記の応力Ｌｂは、略０であり、サブ振動部１１０ｓの共振振動時に生ずる応力のほとんどが金属板部で生じていた。 The stress La in the second direction (X-axis direction) in the range of 0 mm or more and 1 mm or less from the second surface 2S in the first direction (Z-axis direction) is stress generated in the metal plate portion. The stress Lb in the second direction (X-axis direction) in the range of more than 1 mm and less than 2 mm from the second surface 2S in the first direction (Z-axis direction) is stress generated in the exterior portion 110. The above-mentioned stress Lb was approximately 0, and most of the stress generated during resonance vibration of the sub-vibration section 110s was generated in the metal plate section.
　図７に示すように、サブ振動部１１０ｓの共振振動は、ベンディングモードであるため、サブ振動部１１０ｓの上側と下側とで応力の極性が反対になる。図３４に示すように、上記の応力Ｌａは、金属板部の厚みの略中央である、第１方向(Ｚ軸方向)における第２面２Ｓから０．５５ｍｍの位置を境にして、極性が反対になっていた。極性が正である応力Ｌａは、引張応力であり、極性が負である応力Ｌａは、圧縮応力である。すなわち、第１方向(Ｚ軸方向)における第２面２Ｓからの位置が０ｍｍ以上０．５５ｍｍ以下の範囲の金属板部に引張応力が生じ、第１方向(Ｚ軸方向)における第２面２Ｓからの位置が０．５５ｍｍ超１ｍｍ以下の範囲の金属板部に圧縮応力が生じていた。 As shown in FIG. 7, since the resonant vibration of the sub-vibrating section 110s is in a bending mode, the polarity of the stress is opposite between the upper side and the lower side of the sub-vibrating section 110s. As shown in FIG. 34, the above-mentioned stress La has a polarity at a position 0.55 mm from the second surface 2S in the first direction (Z-axis direction), which is approximately the center of the thickness of the metal plate portion. It was the opposite. Stress La with positive polarity is tensile stress, and stress La with negative polarity is compressive stress. That is, tensile stress is generated in the metal plate portion in the range of 0 mm or more and 0.55 mm or less from the second surface 2S in the first direction (Z-axis direction), and the second surface 2S in the first direction (Z-axis direction) Compressive stress was generated in the metal plate portion within a range of more than 0.55 mm and 1 mm or less from the point.
　この金属板部内の第１方向(Ｚ軸方向)における応力分布にしたがって、金属板部に形成される有底溝の深さによってサブ振動部１１０ｓの共振振幅が変動するが、引張応力が生ずる領域と圧縮応力が生ずる領域とのいずれに有底溝が主に位置しているかによってサブ振動部１１０ｓの共振振幅の変動傾向が決まる。 According to the stress distribution in the first direction (Z-axis direction) within the metal plate part, the resonance amplitude of the sub-vibrating part 110s varies depending on the depth of the bottomed groove formed in the metal plate part, but there is a region where tensile stress occurs. The fluctuation tendency of the resonance amplitude of the sub-vibrating portion 110s is determined depending on where the bottomed groove is mainly located between the region where the bottomed groove is located and the region where compressive stress occurs.
　たとえば、実施形態２に係る第１有底溝２５１の深さが０．３ｍｍである場合、第１有底溝２５１は引張応力が生ずる領域にのみ形成されているため、当該引張応力による曲げ変位の増加によってサブ振動部１１０ｓの共振振幅が大きくなる。実施形態２に係る第１有底溝２５１の深さが０．７ｍｍである場合、第１有底溝２５１は引張応力が生ずる領域および圧縮応力が生ずる領域の両方に形成されているが、引張応力が生ずる領域に形成されている部分が第１有底溝２５１の大部分を占めるため、当該引張応力による曲げ変位の増加によってサブ振動部１１０ｓの共振振幅が大きくなる。 For example, when the depth of the first bottomed groove 251 according to the second embodiment is 0.3 mm, since the first bottomed groove 251 is formed only in a region where tensile stress occurs, the bending displacement due to the tensile stress The resonance amplitude of the sub-vibrating section 110s increases due to the increase in . When the depth of the first bottomed groove 251 according to the second embodiment is 0.7 mm, the first bottomed groove 251 is formed in both a region where tensile stress occurs and a region where compressive stress occurs; Since the portion formed in the region where stress occurs occupies most of the first bottomed groove 251, the resonance amplitude of the sub-vibrating portion 110s increases due to an increase in bending displacement due to the tensile stress.
　たとえば、実施形態３に係る第２有底溝３５１の深さが０．３ｍｍである場合、第２有底溝３５１は圧縮応力が生ずる領域にのみ形成されているため、当該圧縮応力による曲げ変位の増加によってサブ振動部１１０ｓの共振振幅が大きくなる。実施形態３に係る第２有底溝３５１の深さが０．７ｍｍである場合、第２有底溝３５１は圧縮応力が生ずる領域および引張応力が生ずる領域の両方に形成されているが、圧縮応力が生ずる領域に形成されている部分が第２有底溝３５１の大部分を占めるため、当該圧縮応力による曲げ変位の増加によってサブ振動部１１０ｓの共振振幅が大きくなる。 For example, when the depth of the second bottomed groove 351 according to the third embodiment is 0.3 mm, the second bottomed groove 351 is formed only in a region where compressive stress occurs, so that the bending displacement due to the compressive stress The resonance amplitude of the sub-vibrating section 110s increases due to the increase in . When the depth of the second bottomed groove 351 according to the third embodiment is 0.7 mm, the second bottomed groove 351 is formed in both a region where compressive stress occurs and a region where tensile stress occurs; Since the portion formed in the region where stress occurs occupies most of the second bottomed groove 351, the resonance amplitude of the sub-vibrating portion 110s increases due to an increase in bending displacement due to the compressive stress.
　このように、第１有底溝２５１の深さの寸法は、金属板部２５０の厚みの寸法の半分に限定されず、金属板部２５０の厚みの寸法の３０％以上７０％以下であってもよい。同様に、第２有底溝３５１の深さの寸法は、金属板部３５０の厚みの寸法の半分に限定されず、金属板部３５０の厚みの寸法の３０％以上７０％以下であってもよい。 In this way, the depth of the first bottomed groove 251 is not limited to half the thickness of the metal plate portion 250, but may be between 30% and 70% of the thickness of the metal plate portion 250. Good too. Similarly, the depth of the second bottomed groove 351 is not limited to half the thickness of the metal plate portion 350, but may be between 30% and 70% of the thickness of the metal plate portion 350. good.
　第１有底溝２５１および第２有底溝３５１の各々の第２方向(Ｘ軸方向)の幅の寸法が大きくなるにしたがって、サブ振動部１１０ｓの共振振幅を大きくする効果は上がるが、超音波トランスデューサの温度特性を安定させる効果は下がる。超音波トランスデューサの温度特性を安定させつつサブ振動部１１０ｓの共振振幅を大きくすることができる、第１有底溝２５１または第２有底溝３５１を金属板部に容易に形成するためには、有底溝の幅と深さとが同程度、または、有底溝の幅と金属板部の厚みとが同程度であることが好ましい。 As the width dimension of each of the first bottomed groove 251 and the second bottomed groove 351 in the second direction (X-axis direction) increases, the effect of increasing the resonance amplitude of the sub-vibration section 110s increases; The effect of stabilizing the temperature characteristics of the acoustic wave transducer is reduced. In order to easily form the first bottomed groove 251 or the second bottomed groove 351 in the metal plate part, which can increase the resonance amplitude of the sub-vibration part 110s while stabilizing the temperature characteristics of the ultrasonic transducer, It is preferable that the width and depth of the bottomed groove are approximately the same, or that the width of the bottomed groove and the thickness of the metal plate portion are approximately the same.
　(実施形態４)
　以下、本発明の実施形態４に係る超音波トランスデューサについて図を参照して説明する。本発明の実施形態４に係る超音波トランスデューサは、金属板部に第１有底溝および第２有底溝の両方が形成されている点が本発明の実施形態２または実施形態３に係る超音波トランスデューサと異なるため、本発明の実施形態２または実施形態３に係る超音波トランスデューサと同様である構成については説明を繰り返さない。 (Embodiment 4)
An ultrasonic transducer according to Embodiment 4 of the present invention will be described below with reference to the drawings. The ultrasonic transducer according to Embodiment 4 of the present invention is characterized in that both the first bottomed groove and the second bottomed groove are formed in the metal plate portion. Since this embodiment differs from the sonic transducer, the description of the configuration that is similar to the ultrasonic transducer according to Embodiment 2 or 3 of the present invention will not be repeated.
　図３５は、本発明の実施形態４に係る超音波トランスデューサの構成を示す縦断面図である。図３５に示すように、本発明の実施形態４に係る超音波トランスデューサ４００は、外装部１１０と、筒体１２０と、超音波振動子１３０と、拘束部１４０と、金属板部４５０とを備える。 FIG. 35 is a longitudinal cross-sectional view showing the configuration of an ultrasonic transducer according to Embodiment 4 of the present invention. As shown in FIG. 35, an ultrasonic transducer 400 according to Embodiment 4 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 450. .
　金属板部４５０の第２面２Ｓにおいて、第１方向(Ｚ軸方向)から見て金属板部４５０のサブ振動部１１０ｓとなる位置に、第３方向(Ｙ軸方向)に延在する第１有底溝２５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、第１有底溝２５１の中心２５１ｃは、２５％以上６０％以下の位置または８３％以上の位置に配置されている。本実施形態においては、第１有底溝２５１の深さの寸法は、金属板部４５０の厚みの寸法の半分である。 On the second surface 2S of the metal plate part 450, a first vibration part extending in the third direction (Y-axis direction) is located at a position that becomes the sub-vibrating part 110s of the metal plate part 450 when viewed from the first direction (Z-axis direction). A bottomed groove 251 is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 251c of the first bottomed groove 251 is located at a position of 25% or more and 60% or less or 83% or more. In this embodiment, the depth of the first bottomed groove 251 is half the thickness of the metal plate portion 450.
　金属板部４５０の第１面１Ｓにおいて、第１方向(Ｚ軸方向)から見て金属板部４５０のサブ振動部１１０ｓとなる位置に、第３方向(Ｙ軸方向)に延在する第２有底溝３５１が形成されている。第１方向(Ｚ軸方向)から見て、筒体１２０と拘束部１４０との間における第２方向(Ｘ軸方向)の位置範囲において筒体１２０の外縁を０％の位置とするとともに拘束部１４０の内縁を１００％の位置としたとき、第２有底溝３５１の中心３５１ｃは、１６％以上７６％以下の位置または９４％以上の位置に配置されている。本実施形態においては、第２有底溝３５１の深さの寸法は、金属板部４５０の厚みの寸法の半分である。 On the first surface 1S of the metal plate part 450, a second vibration part extending in the third direction (Y-axis direction) is located at a position that becomes the sub-vibration part 110s of the metal plate part 450 when viewed from the first direction (Z-axis direction). A bottomed groove 351 is formed. When viewed from the first direction (Z-axis direction), the outer edge of the cylinder 120 is set at 0% position in the position range in the second direction (X-axis direction) between the cylinder 120 and the restraint part 140, and the restraint part When the inner edge of the groove 140 is taken as the 100% position, the center 351c of the second bottomed groove 351 is arranged at a position of 16% or more and 76% or less or a position of 94% or more. In this embodiment, the depth of the second bottomed groove 351 is half the thickness of the metal plate portion 450.
　図３６は、金属板部に有底溝が形成されていない超音波トランスデューサ、金属板部に第１有底溝のみが形成されている超音波トランスデューサ、金属板部に第２有底溝のみが形成されている超音波トランスデューサ、および、金属板部に第１有底溝および第２有底溝が形成されている超音波トランスデューサの、４つのケースについて、有限要素法を用いてシミュレーション解析した指向性を示すグラフである。図３６においては、縦軸に、音圧レベル(ｄＢ)、円周軸に、メイン振動部の中心からの放射角度(°)を示している。また、金属板部に有底溝が形成されていない超音波トランスデューサの指向性を実線、金属板部に第１有底溝のみが形成されている超音波トランスデューサの指向性を点線、金属板部に第２有底溝のみが形成されている超音波トランスデューサの指向性を１点鎖線、金属板部に第１有底溝および第２有底溝が形成されている超音波トランスデューサの指向性を２点鎖線で示している。なお、上記の４つのケースの各々において、放射角度θ＝０°の正面方向における音圧レベルを０ｄＢとして、放射角度θと音圧レベルとの推移を示している。 FIG. 36 shows an ultrasonic transducer in which no bottomed groove is formed in the metal plate part, an ultrasonic transducer in which only the first bottomed groove is formed in the metal plate part, and an ultrasonic transducer in which only the second bottomed groove is formed in the metal plate part. Orientation that was simulated and analyzed using the finite element method for four cases: an ultrasonic transducer that has been formed, and an ultrasonic transducer that has a first bottomed groove and a second bottomed groove formed in the metal plate part. This is a graph showing the characteristics. In FIG. 36, the vertical axis shows the sound pressure level (dB), and the circumferential axis shows the radiation angle (°) from the center of the main vibrating section. In addition, the solid line represents the directivity of the ultrasonic transducer in which the bottomed groove is not formed in the metal plate part, and the dotted line represents the directivity of the ultrasonic transducer in which only the first bottomed groove is formed in the metal plate part. The one-dot chain line represents the directivity of the ultrasonic transducer in which only the second bottomed groove is formed, and the directivity of the ultrasonic transducer in which the first and second bottomed grooves are formed in the metal plate is shown by the dashed line. It is shown by a two-dot chain line. In addition, in each of the above four cases, the transition of the radiation angle θ and the sound pressure level is shown assuming that the sound pressure level in the front direction when the radiation angle θ=0° is 0 dB.
　図３６に示すように、金属板部４５０に第１有底溝２５１および第２有底溝３５１が形成されている本実施形態に係る超音波トランスデューサ４００の指向性の角度範囲が他の３つの超音波トランスデューサよりも広くなっていた。 As shown in FIG. 36, the angular range of directivity of the ultrasonic transducer 400 according to this embodiment in which the first bottomed groove 251 and the second bottomed groove 351 are formed in the metal plate portion 450 is different from that of the other three. It was wider than the ultrasonic transducer.
　本実施形態に係る超音波トランスデューサ４００においても、指向性の角度範囲を広く確保しつつ超音波トランスデューサ４００を小型化することができる。 Also in the ultrasonic transducer 400 according to this embodiment, it is possible to downsize the ultrasonic transducer 400 while ensuring a wide angular range of directivity.
　図３７は、本発明の実施形態４の変形例に係る超音波トランスデューサの構成を示す縦断面図である。図３７に示すように、本発明の実施形態４の変形例に係る超音波トランスデューサ４００ａは、外装部１１０と、筒体１２０と、超音波振動子１３０と、拘束部１４０と、金属板部４５０ａとを備える。 FIG. 37 is a longitudinal sectional view showing the configuration of an ultrasonic transducer according to a modification of Embodiment 4 of the present invention. As shown in FIG. 37, an ultrasonic transducer 400a according to a modification of Embodiment 4 of the present invention includes an exterior portion 110, a cylindrical body 120, an ultrasonic transducer 130, a restraining portion 140, and a metal plate portion 450a. Equipped with.
　金属板部４５０ａには、第１有底溝として、第１方向(Ｚ軸方向)から見て中心２５１ｃが２５％以上６０％以下の位置に配置されている第１有底溝２５１および中心２５１ｃが８３％以上の位置に配置されている第１有底溝２５１の各々が、第２面２Ｓに形成されている。 The metal plate portion 450a has a first bottomed groove 251 and a center 251c arranged at a position of 25% or more and 60% or less when viewed from the first direction (Z-axis direction). Each of the first bottomed grooves 251, which are arranged at a position where the angle is 83% or more, is formed on the second surface 2S.
　金属板部４５０ａの第１面１Ｓには、第１方向(Ｚ軸方向)から見て中心３５１ｃが１６％以上７６％以下の位置または９４％以上の位置に配置されている第２有底溝３５１が形成されている。なお、金属板部４５０ａに、第２有底溝として、第１方向(Ｚ軸方向)から見て中心３５１ｃが１６％以上７６％以下の位置に配置されている第２有底溝３５１および中心３５１ｃが９４％以上の位置に配置されている第２有底溝３５１の各々が、第１面１Ｓに形成されていてもよい。 The first surface 1S of the metal plate portion 450a has a second bottomed groove whose center 351c is located at a position of 16% to 76% or 94% or more when viewed from the first direction (Z-axis direction). 351 is formed. Note that the second bottomed groove 351 and the center of the metal plate portion 450a are arranged as second bottomed grooves, with the center 351c located at a position of 16% or more and 76% or less when viewed from the first direction (Z-axis direction). Each of the second bottomed grooves 351 arranged at a position where 351c is 94% or more may be formed on the first surface 1S.
　本変形例に係る超音波トランスデューサ４００ａにおいても、指向性の角度範囲を広く確保しつつ超音波トランスデューサ４００ａを小型化することができる。 Also in the ultrasonic transducer 400a according to this modification, it is possible to downsize the ultrasonic transducer 400a while ensuring a wide angular range of directivity.
　(付記)
　上述した例示的な実施形態は、以下の態様の具体例であることが当業者により理解される。 (Additional note)
It will be appreciated by those skilled in the art that the exemplary embodiments described above are specific examples of the following aspects.
　＜１＞
　内面取付面を有する外装部と、
　前記内面取付面に取り付けられ、前記内面取付面に沿って延在している金属板部と、
　前記金属板部に取り付けられた筒体と、
　前記筒体に取り付けられており、前記金属板部に間隔をあけて対向する超音波振動子と、
　前記金属板部に取り付けられており、前記筒体に一定の間隔をあけて前記筒体を挟んでいる拘束部とを備え、
　前記内面取付面に直交する第１方向から見て、前記外装部および前記金属板部における前記筒体の内側に位置する部分であるメイン振動部は、前記超音波振動子とは前記第１方向において逆位相で共振振動し、
　前記第１方向から見て、前記第１方向と直交する第２方向において前記外装部および前記金属板部における前記筒体の外側かつ前記拘束部の内側に位置する部分であるサブ振動部は、前記メイン振動部とは前記第１方向において逆位相で共振振動し、
　前記第１方向から見て、前記金属板部の前記サブ振動部となる位置に、前記金属板部を貫通しつつ前記筒体の外縁に並行前記第１方向および前記第２方向の各々に直交する第３方向に延在するスリットが形成されており、
　前記第１方向から見て、前記筒体と前記拘束部との間における前記第２方向の位置範囲において前記筒体の外縁を０％の位置とするとともに前記拘束部の内縁を１００％の位置としたとき、前記スリットの中心は、３５％以上の位置に配置されている、超音波トランスデューサ。 <1>
an exterior part having an inner mounting surface;
a metal plate portion attached to the inner surface mounting surface and extending along the inner surface mounting surface;
a cylindrical body attached to the metal plate part;
an ultrasonic transducer attached to the cylindrical body and facing the metal plate part with a space therebetween;
a restraining part attached to the metal plate part and sandwiching the cylinder at a constant interval,
When viewed from a first direction perpendicular to the inner surface mounting surface, the main vibrating portion, which is a portion of the exterior portion and the metal plate portion located inside the cylinder, is different from the ultrasonic vibrator in the first direction. oscillates resonantly with opposite phase at
When viewed from the first direction, a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
When viewed from the first direction, a metal plate is provided at a position of the metal plate portion that becomes the sub-vibration portion, and is parallel to the outer edge of the cylinder while penetrating the metal plate portion and perpendicular to each of the first direction and the second direction. A slit extending in a third direction is formed,
When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position. In the ultrasonic transducer, the center of the slit is located at a position of 35% or more.
　＜２＞
　内面取付面を有する外装部と、
　前記内面取付面に取り付けられ、前記内面取付面に沿って延在している金属板部と、
　前記金属板部に取り付けられた筒体と、
　前記筒体に取り付けられており、前記金属板部に間隔をあけて対向する超音波振動子と、
　前記金属板部に取り付けられており、前記筒体に一定の間隔をあけて前記筒体を挟んでいる拘束部とを備え、
　前記内面取付面に直交する第１方向から見て、前記外装部および前記金属板部における前記筒体の内側に位置する部分であるメイン振動部は、前記超音波振動子とは前記第１方向において逆位相で共振振動し、
　前記第１方向から見て、前記第１方向と直交する第２方向において前記外装部および前記金属板部における前記筒体の外側かつ前記拘束部の内側に位置する部分であるサブ振動部は、前記メイン振動部とは前記第１方向において逆位相で共振振動し、
　前記金属板部における外装部側の第１面とは反対の第２面において、前記第１方向から見て前記金属板部の前記サブ振動部となる位置に、前記第１方向および前記第２方向の各々に直交する第３方向前記筒体の外縁に並行に延在する第１有底溝が形成されており、
　前記第１方向から見て、前記筒体と前記拘束部との間における前記第２方向の位置範囲において前記筒体の外縁を０％の位置とするとともに前記拘束部の内縁を１００％の位置としたとき、前記第１有底溝の中心は、２５％以上６０％以下の位置または８３％以上の位置に配置されている、超音波トランスデューサ。 <2>
an exterior part having an inner mounting surface;
a metal plate portion attached to the inner surface mounting surface and extending along the inner surface mounting surface;
a cylindrical body attached to the metal plate part;
an ultrasonic transducer attached to the cylindrical body and facing the metal plate part with a space therebetween;
a restraining part attached to the metal plate part and sandwiching the cylinder at a constant interval,
When viewed from a first direction perpendicular to the inner surface mounting surface, the main vibrating portion, which is a portion of the exterior portion and the metal plate portion located inside the cylinder, is different from the ultrasonic vibrator in the first direction. oscillates resonantly with opposite phase at
When viewed from the first direction, a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
On a second surface of the metal plate part opposite to the first surface on the exterior part side, the first direction and the second a first bottomed groove extending parallel to the outer edge of the cylindrical body in a third direction perpendicular to each direction;
When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position. In the ultrasonic transducer, the center of the first bottomed groove is located at a position of 25% or more and 60% or less or 83% or more.
　＜３＞
　内面取付面を有する外装部と、
　前記内面取付面に取り付けられ、前記内面取付面に沿って延在している金属板部と、
　前記金属板部に取り付けられた筒体と、
　前記筒体に取り付けられており、前記金属板部に間隔をあけて対向する超音波振動子と、
　前記金属板部に取り付けられており、前記筒体に一定の間隔をあけて前記筒体を挟んでいる拘束部とを備え、
　前記内面取付面に直交する第１方向から見て、前記外装部および前記金属板部における前記筒体の内側に位置する部分であるメイン振動部は、前記超音波振動子とは前記第１方向において逆位相で共振振動し、
　前記第１方向から見て、前記第１方向と直交する第２方向において前記外装部および前記金属板部における前記筒体の外側かつ前記拘束部の内側に位置する部分であるサブ振動部は、前記メイン振動部とは前記第１方向において逆位相で共振振動し、
　前記金属板部における外装部側の第１面において、前記第１方向から見て前記金属板部の前記サブ振動部となる位置に、前記第１方向および前記第２方向の各々に直交する第３方向前記筒体の外縁に並行に延在する第２有底溝が形成されており、
　前記第１方向から見て、前記筒体と前記拘束部との間における前記第２方向の位置範囲において前記筒体の外縁を０％の位置とするとともに前記拘束部の内縁を１００％の位置としたとき、前記第２有底溝の中心は、１６％以上７６％以下の位置または９４％以上の位置に配置されている、超音波トランスデューサ。 <3>
an exterior part having an inner mounting surface;
a metal plate portion attached to the inner surface mounting surface and extending along the inner surface mounting surface;
a cylindrical body attached to the metal plate part;
an ultrasonic transducer attached to the cylindrical body and facing the metal plate part with a space therebetween;
a restraining part attached to the metal plate part and sandwiching the cylinder at a constant interval,
When viewed from a first direction perpendicular to the inner surface mounting surface, the main vibrating portion, which is a portion of the exterior portion and the metal plate portion located inside the cylinder, is different from the ultrasonic vibrator in the first direction. oscillates resonantly with opposite phase at
When viewed from the first direction, a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
On the first surface of the metal plate part on the exterior part side, at a position of the metal plate part that becomes the sub-vibration part when viewed from the first direction, a first surface perpendicular to each of the first direction and the second direction is provided. A second bottomed groove is formed that extends in parallel to the outer edge of the cylindrical body in three directions,
When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position. In the ultrasonic transducer, the center of the second bottomed groove is located at a position of 16% or more and 76% or less or a position of 94% or more.
　＜４＞
　前記第１面において、前記第１方向から見て前記金属板部の前記サブ振動部となる位置に、前記第３方向前記筒体の外縁に並行に延在する第２有底溝が形成されており、
　前記第１方向から見て、前記第２有底溝の中心は、１６％以上７６％以下の位置または９４％以上の位置に配置されている、＜２＞に記載の超音波トランスデューサ。 <4>
On the first surface, a second bottomed groove extending parallel to the outer edge of the cylindrical body in the third direction is formed at a position of the metal plate section that becomes the sub-vibration section when viewed from the first direction. and
The ultrasonic transducer according to <2>, wherein the center of the second bottomed groove is located at a position of 16% or more and 76% or less or 94% or more when viewed from the first direction.
　＜５＞
　前記第１有底溝として、前記第１方向から見て中心が２５％以上６０％以下の位置に配置されている第１有底溝および中心が８３％以上の位置に配置されている第１有底溝の各々が前記第２面に形成されている、＜４＞に記載の超音波トランスデューサ。 <5>
The first bottomed groove includes a first bottomed groove whose center is located at a position of 25% to 60% when viewed from the first direction, and a first bottomed groove whose center is located at a position of 83% or more. The ultrasonic transducer according to <4>, wherein each bottomed groove is formed on the second surface.
　＜６＞
　前記拘束部の基本モードの共振周波数は、前記超音波振動子の共振周波数に比較して２０％以上低い周波数であり、
　前記拘束部の高次モードの共振周波数は、前記超音波振動子の共振周波数に比較して２０％以上高い周波数である、＜１＞から＜５＞のいずれか１つに記載の超音波トランスデューサ。 <6>
The resonance frequency of the fundamental mode of the restraining portion is 20% or more lower than the resonance frequency of the ultrasonic transducer,
The ultrasonic transducer according to any one of <1> to <5>, wherein the resonance frequency of the higher-order mode of the restraint part is 20% or more higher than the resonance frequency of the ultrasonic transducer. .
　＜７＞
　前記超音波振動子は、積層された２つの圧電体を含み、
　前記２つの圧電体の各々は、第１電極および第２電極に挟まれて交流電圧を印加可能に構成されており、
　前記第１電極は、接地電位に固定されており、
　前記筒体および前記拘束部の各々は、金属で構成されており、
　前記第１電極、前記筒体、前記金属板部および前記拘束部は、機械的かつ電気的に互いに接続されて電磁シールドを構成している、＜１＞から＜６＞のいずれか１つに記載の超音波トランスデューサ。 <7>
The ultrasonic vibrator includes two laminated piezoelectric bodies,
Each of the two piezoelectric bodies is configured to be sandwiched between a first electrode and a second electrode so that an alternating current voltage can be applied thereto,
The first electrode is fixed to a ground potential,
Each of the cylinder body and the restraint part is made of metal,
The first electrode, the cylindrical body, the metal plate part, and the restraint part are mechanically and electrically connected to each other to constitute an electromagnetic shield, and in any one of <1> to <6>. Ultrasonic transducer as described.
　＜８＞
　前記外装部は、ポリプロピレンを主成分とする樹脂で構成されており、
　前記金属板部は、アルミニウム合金で構成されており、
　前記メイン振動部および前記サブ振動部の各々を構成する部分の前記外装部の厚みに対する、前記金属板部の厚みの比率は１００％以上１６０％以下である、＜１＞から＜７＞のいずれか１つに記載の超音波トランスデューサ。 <8>
The exterior part is made of resin whose main component is polypropylene,
The metal plate portion is made of an aluminum alloy,
Any one of <1> to <7>, wherein the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part is 100% or more and 160% or less. The ultrasonic transducer according to any one of the above.
　＜９＞
　前記外装部は、ポリプロピレン主成分とする樹脂で構成されており、
　前記金属板部は、ステンレス鋼で構成されており、
　前記メイン振動部および前記サブ振動部の各々を構成する部分の前記外装部の厚みに対する、前記金属板部の厚みの比率は６０％以上１００％以下である、＜１＞から＜７＞のいずれか１つに記載の超音波トランスデューサ。 <9>
The exterior part is made of resin mainly composed of polypropylene,
The metal plate portion is made of stainless steel,
Any one of <1> to <7>, wherein the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part is 60% or more and 100% or less. The ultrasonic transducer according to any one of the above.
　＜１０＞
　前記金属板部、前記筒体および前記拘束部は、一体で形成されている、＜１＞から＜９＞のいずれか１つに記載の超音波トランスデューサ。 <10>
The ultrasonic transducer according to any one of <1> to <9>, wherein the metal plate part, the cylinder body, and the restraining part are integrally formed.
　上述した実施形態の説明において、組み合わせ可能な構成を相互に組み合わせてもよい。 In the description of the embodiments described above, combinable configurations may be combined with each other.
　今回開示された実施形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that equivalent meanings and all changes within the scope of the claims are included.
　１Ｓ　第１面、２Ｓ　第２面、１０　処理回路、１００，１００ａ，１００ｂ，２００，３００，４００，４００ａ　超音波トランスデューサ、１１０　外装部、１１０ｍ　メイン振動部、１１０ｓ　サブ振動部、１１１　内面、１１２　凹部、１２０，１２０ａ　筒体、１３０，１３０ａ，１３０ｂ，１３０ｃ　超音波振動子、１３１　圧電体、１３２　第１電極、１３３　第２電極、１３４　中間電極、１３５　振動板、１４０　拘束部、１５０，１５０ｂ，１５０ｃ，１５０ｄ，１５０ｅ，１５０ｆ，２５０，３５０，４５０，４５０ａ　金属板部、１５１　スリット、２５１　第１有底溝、２６０　ダンピング材、３５１　第２有底溝、ＭＳ　メイン音源、ＳＳ　サブ音源。 1S 1st surface, 2S 2nd surface, 10 processing circuit, 100, 100a, 100b, 200, 300, 400, 400a ultrasonic transducer, 110 exterior part, 110m main vibration part, 110s sub vibration part, 111 inner surface, 112 concave part , 120, 120a Cylindrical body, 130, 130a, 130b, 130c Ultrasonic transducer, 131 Piezoelectric body, 132 First electrode, 133 Second electrode, 134 Intermediate electrode, 135 Vibration plate, 140 Restraint part, 150, 150b, 150c , 150d, 150e, 150f, 250, 350, 450, 450a metal plate part, 151 slit, 251 first bottomed groove, 260 damping material, 351 second bottomed groove, MS main sound source, SS sub sound source.

Claims (10)

  1. 　取付面を有する外装部と、
    　前記取付面に取り付けられ、前記取付面に沿って延在している金属板部と、
    　前記金属板部に取り付けられた筒体と、
    　前記筒体に取り付けられており、前記金属板部に間隔をあけて対向する超音波振動子と、
    　前記金属板部に取り付けられており、前記筒体に一定の間隔をあけて前記筒体を挟んでいる拘束部とを備え、
    　前記取付面に直交する第１方向から見て前記外装部および前記金属板部における前記筒体の内側に位置する部分であるメイン振動部は、前記超音波振動子とは前記第１方向において逆位相で共振振動し、
    　前記第１方向から見て、前記第１方向と直交する第２方向において前記外装部および前記金属板部における前記筒体の外側かつ前記拘束部の内側に位置する部分であるサブ振動部は、前記メイン振動部とは前記第１方向において逆位相で共振振動し、
    　前記第１方向から見て、前記金属板部の前記サブ振動部となる位置に、前記金属板部を貫通しつつ前記第１方向および前記第２方向の各々に直交する第３方向に延在するスリットが形成されており、
    　前記第１方向から見て、前記筒体と前記拘束部との間における前記第２方向の位置範囲において前記筒体の外縁を０％の位置とするとともに前記拘束部の内縁を１００％の位置としたとき、前記スリットの中心は、３５％以上の位置に配置されている、超音波トランスデューサ。     an exterior part having a mounting surface;
    a metal plate portion attached to the mounting surface and extending along the mounting surface;
    a cylindrical body attached to the metal plate part;
    an ultrasonic transducer attached to the cylindrical body and facing the metal plate part with a space therebetween;
    a restraining part attached to the metal plate part and sandwiching the cylinder at a constant interval,
    A main vibrating portion, which is a portion of the exterior portion and the metal plate portion located inside the cylindrical body when viewed from a first direction perpendicular to the mounting surface, is opposite to the ultrasonic vibrator in the first direction. resonantly vibrates in phase,
    When viewed from the first direction, a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
    When viewed from the first direction, extending in a third direction perpendicular to each of the first direction and the second direction while penetrating the metal plate portion at a position of the metal plate portion that becomes the sub-vibration portion. A slit is formed to
    When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position. In the ultrasonic transducer, the center of the slit is located at a position of 35% or more.
  2. 　取付面を有する外装部と、
    　前記取付面に取り付けられ、前記取付面に沿って延在している金属板部と、
    　前記金属板部に取り付けられた筒体と、
    　前記筒体に取り付けられており、前記金属板部に間隔をあけて対向する超音波振動子と、
    　前記金属板部に取り付けられており、前記筒体に一定の間隔をあけて前記筒体を挟んでいる拘束部とを備え、
    　前記取付面に直交する第１方向から見て前記外装部および前記金属板部における前記筒体の内側に位置する部分であるメイン振動部は、前記超音波振動子とは前記第１方向において逆位相で共振振動し、
    　前記第１方向から見て、前記第１方向と直交する第２方向において前記外装部および前記金属板部における前記筒体の外側かつ前記拘束部の内側に位置する部分であるサブ振動部は、前記メイン振動部とは前記第１方向において逆位相で共振振動し、
    　前記金属板部における外装部側の第１面とは反対の第２面において、前記第１方向から見て前記金属板部の前記サブ振動部となる位置に、前記第１方向および前記第２方向の各々に直交する第３方向に延在する第１有底溝が形成されており、
    　前記第１方向から見て、前記筒体と前記拘束部との間における前記第２方向の位置範囲において前記筒体の外縁を０％の位置とするとともに前記拘束部の内縁を１００％の位置としたとき、前記第１有底溝の中心は、２５％以上６０％以下の位置または８３％以上の位置に配置されている、超音波トランスデューサ。     an exterior part having a mounting surface;
    a metal plate portion attached to the mounting surface and extending along the mounting surface;
    a cylindrical body attached to the metal plate part;
    an ultrasonic transducer attached to the cylindrical body and facing the metal plate part with a space therebetween;
    a restraining part attached to the metal plate part and sandwiching the cylinder at a constant interval,
    A main vibrating portion, which is a portion of the exterior portion and the metal plate portion located inside the cylindrical body when viewed from a first direction perpendicular to the mounting surface, is opposite to the ultrasonic vibrator in the first direction. resonantly vibrates in phase,
    When viewed from the first direction, a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
    On a second surface of the metal plate part opposite to the first surface on the exterior part side, the first direction and the second A first bottomed groove is formed extending in a third direction perpendicular to each of the directions,
    When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position. In the ultrasonic transducer, the center of the first bottomed groove is located at a position of 25% or more and 60% or less or 83% or more.
  3. 　取付面を有する外装部と、
    　前記取付面に取り付けられ、前記取付面に沿って延在している金属板部と、
    　前記金属板部に取り付けられた筒体と、
    　前記筒体に取り付けられており、前記金属板部に間隔をあけて対向する超音波振動子と、
    　前記金属板部に取り付けられており、前記筒体に一定の間隔をあけて前記筒体を挟んでいる拘束部とを備え、
    　前記取付面に直交する第１方向から見て前記外装部および前記金属板部における前記筒体の内側に位置する部分であるメイン振動部は、前記超音波振動子とは前記第１方向において逆位相で共振振動し、
    　前記第１方向から見て、前記第１方向と直交する第２方向において前記外装部および前記金属板部における前記筒体の外側かつ前記拘束部の内側に位置する部分であるサブ振動部は、前記メイン振動部とは前記第１方向において逆位相で共振振動し、
    　前記金属板部における外装部側の第１面において、前記第１方向から見て前記金属板部の前記サブ振動部となる位置に、前記第１方向および前記第２方向の各々に直交する第３方向に延在する第２有底溝が形成されており、
    　前記第１方向から見て、前記筒体と前記拘束部との間における前記第２方向の位置範囲において前記筒体の外縁を０％の位置とするとともに前記拘束部の内縁を１００％の位置としたとき、前記第２有底溝の中心は、１６％以上７６％以下の位置または９４％以上の位置に配置されている、超音波トランスデューサ。     an exterior part having a mounting surface;
    a metal plate portion attached to the mounting surface and extending along the mounting surface;
    a cylindrical body attached to the metal plate part;
    an ultrasonic transducer attached to the cylindrical body and facing the metal plate part with a space therebetween;
    a restraining part attached to the metal plate part and sandwiching the cylinder at a constant interval,
    A main vibrating portion, which is a portion of the exterior portion and the metal plate portion located inside the cylindrical body when viewed from a first direction perpendicular to the mounting surface, is opposite to the ultrasonic vibrator in the first direction. vibrates resonantly in phase,
    When viewed from the first direction, a sub-vibrating section is a portion of the exterior section and the metal plate section located outside the cylinder and inside the restraint section in a second direction orthogonal to the first direction. vibrates resonantly in an opposite phase to the main vibrating part in the first direction;
    On the first surface of the metal plate part on the exterior part side, at a position of the metal plate part that becomes the sub-vibration part when viewed from the first direction, a first surface perpendicular to each of the first direction and the second direction is provided. A second bottomed groove extending in three directions is formed,
    When viewed from the first direction, in the position range in the second direction between the cylindrical body and the restraining part, the outer edge of the cylindrical body is at a 0% position, and the inner edge of the restraining part is at a 100% position. In the ultrasonic transducer, the center of the second bottomed groove is located at a position of 16% or more and 76% or less or a position of 94% or more.
  4. 　前記第１面において、前記第１方向から見て前記金属板部の前記サブ振動部となる位置に、前記第３方向に延在する第２有底溝が形成されており、
    　前記第１方向から見て、前記第２有底溝の中心は、１６％以上７６％以下の位置または９４％以上の位置に配置されている、請求項２に記載の超音波トランスデューサ。     On the first surface, a second bottomed groove extending in the third direction is formed at a position of the metal plate section that becomes the sub-vibrating section when viewed from the first direction,
    The ultrasonic transducer according to claim 2, wherein the center of the second bottomed groove is located at a position of 16% or more and 76% or less or 94% or more when viewed from the first direction.
  5. 　前記第１有底溝として、前記第１方向から見て中心が２５％以上６０％以下の位置に配置されている第１有底溝および中心が８３％以上の位置に配置されている第１有底溝の各々が前記第２面に形成されている、請求項４に記載の超音波トランスデューサ。 The first bottomed groove includes a first bottomed groove whose center is located at a position of 25% to 60% when viewed from the first direction, and a first bottomed groove whose center is located at a position of 83% or more. The ultrasonic transducer according to claim 4, wherein each bottomed groove is formed on the second surface.
  6. 　前記拘束部の基本モードの共振周波数は、前記超音波振動子の共振周波数に比較して２０％以上低い周波数であり、
    　前記拘束部の高次モードの共振周波数は、前記超音波振動子の共振周波数に比較して２０％以上高い周波数である、請求項１から請求項５のいずれか１項に記載の超音波トランスデューサ。     The resonance frequency of the fundamental mode of the restraining portion is 20% or more lower than the resonance frequency of the ultrasonic transducer,
    The ultrasonic transducer according to any one of claims 1 to 5, wherein the resonance frequency of the higher-order mode of the restraining portion is 20% or more higher than the resonance frequency of the ultrasonic transducer. .
  7. 　前記超音波振動子は、積層された２つの圧電体を含み、
    　前記２つの圧電体の各々は、第１電極および第２電極に挟まれて交流電圧を印加可能に構成されており、
    　前記第１電極は、接地電位に固定されており、
    　前記筒体および前記拘束部の各々は、金属で構成されており、
    　前記第１電極、前記筒体、前記金属板部および前記拘束部は、機械的かつ電気的に互いに接続されて電磁シールドを構成している、請求項１から請求項６のいずれか１項に記載の超音波トランスデューサ。     The ultrasonic vibrator includes two laminated piezoelectric bodies,
    Each of the two piezoelectric bodies is configured to be sandwiched between a first electrode and a second electrode so that an alternating current voltage can be applied thereto,
    The first electrode is fixed to a ground potential,
    Each of the cylinder body and the restraint part is made of metal,
    The first electrode, the cylindrical body, the metal plate part, and the restraint part are mechanically and electrically connected to each other to constitute an electromagnetic shield, according to any one of claims 1 to 6. Ultrasonic transducer as described.
  8. 　前記外装部は、ポリプロピレンを主成分とする樹脂で構成されており、
    　前記金属板部は、アルミニウム合金で構成されており、
    　前記メイン振動部および前記サブ振動部の各々を構成する部分の前記外装部の厚みに対する、前記金属板部の厚みの比率は１００％以上１６０％以下である、請求項１から請求項７のいずれか１項に記載の超音波トランスデューサ。     The exterior part is made of resin whose main component is polypropylene,
    The metal plate portion is made of an aluminum alloy,
    Any one of claims 1 to 7, wherein the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part is 100% or more and 160% or less. The ultrasonic transducer according to item 1.
  9. 　前記外装部は、ポリプロピレン主成分とする樹脂で構成されており、
    　前記金属板部は、ステンレス鋼で構成されており、
    　前記メイン振動部および前記サブ振動部の各々を構成する部分の前記外装部の厚みに対する、前記金属板部の厚みの比率は６０％以上１００％以下である、請求項１から請求項７のいずれか１項に記載の超音波トランスデューサ。     The exterior part is made of resin mainly composed of polypropylene,
    The metal plate portion is made of stainless steel,
    Any one of claims 1 to 7, wherein the ratio of the thickness of the metal plate part to the thickness of the exterior part of the parts constituting each of the main vibrating part and the sub-vibrating part is 60% or more and 100% or less. The ultrasonic transducer according to item 1.
  10. 　前記金属板部、前記筒体および前記拘束部は、一体で形成されている、請求項１から請求項９のいずれか１項に記載の超音波トランスデューサ。 The ultrasonic transducer according to any one of claims 1 to 9, wherein the metal plate portion, the cylinder body, and the restraining portion are integrally formed.
PCT/JP2022/042880 2022-04-18 2022-11-18 Ultrasonic wave transducer WO2023203805A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004297219A (en) * 2003-03-25 2004-10-21 Nippon Soken Inc Ultrasonic sensor and component with ultrasonic sensor fitted thereto
JP2011055292A (en) * 2009-09-02 2011-03-17 Nippon Ceramic Co Ltd Ultrasonic transceiver

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004297219A (en) * 2003-03-25 2004-10-21 Nippon Soken Inc Ultrasonic sensor and component with ultrasonic sensor fitted thereto
JP2011055292A (en) * 2009-09-02 2011-03-17 Nippon Ceramic Co Ltd Ultrasonic transceiver

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