WO2020250439A1 - Rotation speed detector - Google Patents

Rotation speed detector Download PDF

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Publication number
WO2020250439A1
WO2020250439A1 PCT/JP2019/023729 JP2019023729W WO2020250439A1 WO 2020250439 A1 WO2020250439 A1 WO 2020250439A1 JP 2019023729 W JP2019023729 W JP 2019023729W WO 2020250439 A1 WO2020250439 A1 WO 2020250439A1
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WO
WIPO (PCT)
Prior art keywords
region
magnet
magnetic
rotation speed
rotation
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PCT/JP2019/023729
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French (fr)
Japanese (ja)
Inventor
久範 鳥居
武史 武舎
琢也 野口
雅史 大熊
Original Assignee
三菱電機株式会社
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2019560414A priority Critical patent/JP6647478B1/en
Priority to PCT/JP2019/023729 priority patent/WO2020250439A1/en
Priority to KR1020217036567A priority patent/KR102446180B1/en
Priority to CN201980097323.8A priority patent/CN113939714B/en
Publication of WO2020250439A1 publication Critical patent/WO2020250439A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
    • G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
    • G01D5/2013—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils by a movable ferromagnetic element, e.g. a core

Definitions

  • the present invention relates to a rotation speed detector that detects the rotation speed of a rotating body.
  • Patent Document 1 includes a magnetic wire that causes magnetization reversal due to a large bulkhausen effect based on a change in a magnetic field, and a coil that is wound around the magnetic wire and generates an induced voltage according to the magnetization reversal of the magnetic wire. Number detectors are disclosed.
  • the magnetic wire and the coil face the magnet in the direction perpendicular to the rotation axis of the rotating body, so that the distance between the end of the magnetic wire and the magnet is set between the center of the magnetic wire and the magnet. It will be longer than the interval. Therefore, the magnetic flux from the magnet is weaker at the end of the magnetic wire than at the center of the magnetic wire. Since the large bulkhausen effect is more stable at the center of the magnetic wire than at the end of the magnetic wire, the magnetic flux is weakened at the end of the magnetic wire rather than at the center of the magnetic wire, thereby stabilizing the generation of the induced voltage. .. As a result, the rotation speed detector can reduce the variation in the amount of power generation.
  • the present invention has been made in view of the above, and an object of the present invention is to obtain a rotation speed detector capable of improving the reliability of rotation speed detection.
  • the rotation speed detector has a magnet attached to a rotating body rotating around a rotation axis and an induced voltage according to a change in a magnetic field due to the rotation of the magnet. It has a power generation element that generates the above, and detects the number of rotations of the rotating body based on the induced voltage.
  • the power generation element includes a magnetic wire, a coil wound between the first end and the second end of the magnetic wire, which are both ends of the magnetic wire, and a soft magnetic material, which is the first end and the first end. It has a cylinder provided at each of the two ends.
  • the magnet has a plurality of magnetic poles arranged in the direction of rotation of the magnet. Each of the plurality of magnetic poles has a first region and a second region in which the strengths of the magnetic forces are different from each other.
  • the rotation speed detector according to the present invention has the effect of improving the reliability of rotation speed detection.
  • the figure which shows the rotation speed detector which concerns on Embodiment 1 of this invention Top view showing a magnet and a power generation element included in the rotation speed detector according to the first embodiment. The figure which shows the example of the relationship between the rotation angle of a magnet, and the magnetic flux density in the rotation speed detector which concerns on Embodiment 1. Top view showing a magnet and a power generation element included in the rotation speed detector according to the second embodiment of the present invention. The figure which shows the example of the relationship between the rotation angle of a magnet, and the magnetic flux density in the rotation speed detector which concerns on Embodiment 2. The figure which shows the rotation speed detector which concerns on Embodiment 3 of this invention. The figure which shows the rotation speed detector which concerns on Embodiment 4 of this invention. Top view showing a magnet and a power generation element included in the rotation speed detector according to the fourth embodiment. The figure which shows the rotation speed detector which concerns on Embodiment 5 of this invention.
  • FIG. 1 is a diagram showing a rotation speed detector according to the first embodiment of the present invention.
  • the rotation speed detector 1 according to the first embodiment is a magnetic rotation speed detector that detects the rotation speed of a rotating body based on an induced voltage generated according to a change in a magnetic field.
  • the rotation speed detector 1 detects the number of times the rotating body rotates.
  • the rotation speed detector 1 processes the magnet 2 attached to the shaft 4, the power generation element 3 that generates an induced voltage according to the change in the magnetic field due to the rotation of the magnet 2, and outputs a signal, and the signal from the power generation element 3. It has a processing unit 5.
  • the magnet 2 is a flat plate having a circular shape.
  • the magnet 2 is a permanent magnet.
  • the shaft 4 is a rotating body that rotates around a rotating shaft 9. The magnet 2 is fixed to the tip of the shaft 4 by adhesion, screwing, or press fitting.
  • the shaft 4 is a drive shaft of the motor. In FIG. 1, the motor body that rotates the shaft 4 is not shown.
  • the processing unit 5 counts the number of pulses generated by power generation based on the signal from the power generation element 3.
  • the processing unit 5 detects the rotation speed of the shaft 4 by counting the number of pulses. Since the processing unit 5 can operate using the induced voltage, the rotation speed can be detected without a power source.
  • the power generation element 3 is arranged to face the magnet 2 in a direction parallel to the rotation axis 9.
  • the power generation element 3 faces the surface of the magnet 2 opposite to the surface fixed to the shaft 4.
  • the power generation element 3 may be arranged so as to face the surface of the magnet 2 on the side fixed to the shaft 4.
  • the power generation element 3 includes a magnetic wire 6, a coil 7 wound around the magnetic wire 6, and ferrite beads provided on each of the first end portion 6a and the second end portion 6b, which are both ends of the magnetic wire 6. Has 8 and.
  • the magnetic wire 6 is a magnetic material processed into a wire shape.
  • the magnetic wire 6 causes magnetization reversal due to the large Barkhausen effect based on the change in the magnetic field.
  • the large Barkhausen effect is a phenomenon in which the magnetization direction is reversed in a short time by moving the domain wall inside the magnetic material at once when the magnetic material is magnetized.
  • the coil 7 is wound between the first end portion 6a and the second end portion 6b. That is, the coil 7 is provided between the ferrite beads 8 provided at the first end portion 6a and the ferrite beads 8 provided at the second end portion 6b.
  • the coil 7 is a pickup coil.
  • Ferrite beads 8 are cylinders made of soft magnetic material.
  • the magnetic permeability of the ferrite beads 8 is higher than the magnetic permeability of the magnetic wire 6.
  • One ferrite bead 8 covers the first end portion 6a.
  • the other ferrite bead 8 covers the second end portion 6b.
  • the cylinder provided at the first end portion 6a and the second end portion 6b may be a soft magnetic material other than the ferrite beads 8, or may be a cylinder made of a soft magnetic material such as iron. ..
  • a steel material such as SS400 or S45C, a magnetic stainless steel material such as SUS430 or SUS440, or a high magnetic permeability material such as permalloy or permendur may be used as the soft magnetic material.
  • a steel material such as SS400 or S45C
  • a magnetic stainless steel material such as SUS430 or SUS440
  • a high magnetic permeability material such as permalloy or permendur
  • FIG. 2 is a plan view showing a magnet and a power generation element included in the rotation speed detector according to the first embodiment.
  • FIG. 2 shows a view of the magnet 2 and the power generation element 3 in a direction parallel to the rotating shaft 9 and from a side opposite to the shaft 4.
  • the power generation element 3 is arranged so as to face the magnet 2 at a position away from the center of the circular shape of the magnet 2.
  • the rotation speed detector 1 is generally used in combination with an angle detector that detects the rotation angle of the rotating body.
  • the angle detection unit includes an optical detection disk on which an optical slit is formed, a light emitting unit that generates light, and a light receiving unit that emits light from the light emitting unit and detects light that has passed through the optical slit.
  • the disk is fixed to the rotating body on the upper surface side of the magnet 2.
  • the light emitting unit and the light receiving unit are provided at positions facing the optical slit. In FIGS. 1 and 2, the angle detection unit is not shown.
  • the magnet 2 has a plurality of magnetic poles arranged in the rotation direction of the magnet 2.
  • the magnet 2 has two magnetic poles, a first magnetic pole and a second magnetic pole.
  • the first magnetic pole and the second magnetic pole are two magnetic poles having different magnetizing directions.
  • the magnet 2 is bisected into an N pole 2N, which is the first magnetic pole, and an S pole 2S, which is the second magnetic pole, with the diameter of the circle as a boundary.
  • the magnet 2 is magnetized in a direction parallel to the rotation axis 9.
  • the magnet 2 is not limited to one having a pair of N poles 2N and S pole 2S, and may have two or more pairs of N poles 2N and S poles 2S. That is, the magnet 2 may have four or more magnetic poles. Further, the magnet 2 is not limited to a flat plate having a circular shape, and may be a cylindrical body having an opening at the center.
  • the N pole 2N has two strongly magnetized regions Na1 and Na2, which are the first regions, and one weakly magnetized region Nb, which is the second region.
  • the strong magnetization regions Na1 and Na2 and the weak magnetization regions Nb have the same magnetizing direction and different magnetic force strengths.
  • the weakly magnetized region Nb is a region having a weaker magnetic force than the strongly magnetized regions Na1 and Na2. That is, the surface magnetic flux density of the weakly magnetized region Nb is smaller than the surface magnetic flux density of the strongly magnetized regions Na1 and Na2.
  • the surface magnetic flux density of the strong magnetization region Na1 and the surface magnetic flux density of the strong magnetization region Na2 are about the same.
  • the S pole 2S has two strongly magnetized regions Sa1 and Sa2, which are the first regions, and one weakly magnetized region Sb, which is the second region.
  • the strongly magnetized regions Sa1 and Sa2 and the weakly magnetized regions Sb have the same magnetizing direction and different magnetic force strengths.
  • the weakly magnetized region Sb is a region having a weaker magnetic force than the strongly magnetized regions Sa1 and Sa2. That is, the surface magnetic flux density of the weakly magnetized region Sb is smaller than the surface magnetic flux density of the strongly magnetized regions Sa1 and Sa2.
  • the surface magnetic flux density of the strong magnetization region Sa1 and the surface magnetic flux density of the strong magnetization region Sa2 are about the same.
  • the boundary between the strongly magnetized regions Na1, Na2, Sa1, Sa2 and the weakly magnetized regions Nb and Sb is represented by a solid line.
  • the weak magnetization region Nb is provided between the strong magnetization region Na1 and the strong magnetization region Na2 in the rotation direction. That is, the weakly magnetized region Nb is arranged so as to be sandwiched between the strongly magnetized regions Na1 and Na2 in the rotation direction.
  • the weakly magnetized region Nb is arranged at the center of the N pole 2N in the rotation direction.
  • the weak magnetization region Sb is provided between the strong magnetization region Sa1 and the strong magnetization region Sa2 in the rotation direction. That is, the weakly magnetized region Sb is arranged so as to be sandwiched between the strongly magnetized regions Sa1 and Sa2 in the rotation direction.
  • the weakly magnetized region Sb is arranged at the center of the S pole 2S in the rotation direction.
  • the strong magnetization region Na1 and the strong magnetization region Sa1 are adjacent to each other in the rotation direction.
  • the strong magnetization region Na2 and the strong magnetization region Sa2 are adjacent to each other in the rotation direction.
  • the strong magnetization regions Na1, Na2, Sa1, and Sa2 are provided at the boundary between the N pole 2N and the S pole 2S in the magnet 2.
  • the strong magnetization regions Na1 and Na2 and the weak magnetization region Nb of the N pole 2N and the strong magnetization regions Sa1 and Sa2 and the weak magnetization region Sb of the S pole 2S are magnetized when the magnet 2 is magnetized. This is achieved by changing the strength of the external magnetic field applied to each region of the magnet 2. Two types of materials having different magnetic permeabilitys are used for the yoke core portion of the magnetizing yoke used when magnetizing the magnet 2.
  • the power generation element 3 faces the strong magnetization region Na1 and the strong magnetization region Sa1.
  • the entire power generation element 3 is in a region in which the strong magnetization region Na1 and the strong magnetization region Sa1 are combined.
  • FIG. 3 is a diagram showing an example of the relationship between the rotation angle of the magnet and the magnetic flux density in the rotation speed detector according to the first embodiment.
  • the angle “0 degree” is assumed to be when the magnet 2 is in the state shown in FIG.
  • the horizontal axis of the graph shown in FIG. 3 represents the rotation angle when the magnet 2 is rotated in the counterclockwise direction in FIG.
  • the vertical axis of the graph shown in FIG. 3 represents the magnetic flux density in the magnetic wire 6.
  • the curve M1 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the first embodiment is rotated.
  • the curve M2 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the comparative example is rotated. It is assumed that the magnet 2 of the comparative example has a pair of north and south poles consisting of only a strong magnetization region.
  • the direction of the magnetic flux is parallel to the length direction of the magnetic wire 6.
  • the magnetic flux density when the angle is 0 degrees is a maximum value.
  • the direction of the magnetic flux is opposite to that when the angle is 0 degrees.
  • the magnetic flux density when the angle is 180 degrees is a minimum value.
  • the magnetic flux density decreases uniformly in the range of about 30 degrees to about 150 degrees while the magnet 2 is rotated from 0 degrees to 180 degrees. Further, while rotating the magnet from 180 degrees to 360 degrees, the magnetic flux density increases uniformly in the range from around 210 degrees to around 330 degrees.
  • the magnetic flux density decreases from the maximum value to zero in the range from about 30 degrees to about 70 degrees.
  • the magnetic flux density remains zero in the range from around 70 degrees to around 120 degrees, and decreases from zero to the minimum value in the range from around 120 degrees to around 160 degrees.
  • the magnetic flux density decreases in a narrower angle range than in the case of the comparative example. That is, in the case of the first embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
  • the magnetic flux density increases from the minimum value to zero in the range from about 200 degrees to about 250 degrees.
  • the magnetic flux density remains zero in the range from around 250 degrees to around 300 degrees and increases from zero to the maximum value in the range from around 300 degrees to around 340 degrees.
  • the magnetic flux density increases in a narrower angle range than in the case of the comparative example. That is, in the case of the first embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
  • the weakly magnetized region Sb reaches a position facing the second end portion 6b. Further, by rotating the magnet 2, the strong magnetization regions Na1 and Sa1 are separated from the position facing the power generation element 3, and the weak magnetization region Sb reaches the position facing the power generation element 3.
  • the change in magnetic flux density when the weakly magnetized region Sb passes through the position facing the power generation element 3 is smaller than the change in magnetic flux density when the strong magnetization region Sa1 passes through the position facing the power generation element 3. Therefore, in the case of the first embodiment, the magnetic flux density does not change in the angle range including 90 degrees.
  • the weakly magnetized region Sb moves away from the position facing the power generation element 3, and the strong magnetization regions Sa2 and Na2 reach the position facing the power generation element 3.
  • the magnetic flux density sharply decreases from zero to the minimum value.
  • the change in the magnetic flux density when the magnet 2 rotates from 180 degrees to 360 degrees is the same as the change in the magnetic flux density when the magnet 2 rotates from 0 degrees to 180 degrees, except that the positive and negative of the magnetic flux density are different.
  • the magnetic flux density is reduced in one rotation of the magnet 2 by providing the strong magnetization regions Na1, Na2, Sa1, and Sa2 at the boundary between the N pole 2N and the S pole 2S of the magnet 2.
  • the angle range to be magnetized and the angle range to increase the magnetic flux density are limited.
  • the magnetization reversal in the magnetic wire 6 occurs in an angle range from about 120 degrees to about 160 degrees and an angle range from about 200 degrees to about 250 degrees.
  • the angle range in which the magnetization reversal occurs can be limited as compared with the case of the comparative example.
  • the power generation element 3 can suppress variations in the timing of outputting the induced voltage due to the rotation of the magnet 2.
  • the power generation element 3 can reduce variations in power generation timing each time the magnet 2 rotates.
  • the power generation element 3 can increase the amount of power generation as compared with the case of the comparative example because the change in the magnetic flux density with respect to the change in the angle is steep.
  • the magnetic flux from the magnet 2 can be applied to the entire magnetic wire 6 by the power generation element 3 facing the magnet 2 in the direction parallel to the rotation axis 9. Therefore, the power generation element 3 can increase the amount of power generation as compared with the case where the magnetic flux is applied only to the central portion of the magnetic wire 6.
  • the change in magnetic flux density of the first end portion 6a and the second end portion 6b of the magnetic wire 6 is unstable as compared with the portion of the magnetic wire 6 between the first end portion 6a and the second end portion 6b. Easy to become.
  • the magnetic wire 6 is manufactured by cutting a wire-like material into a size suitable for the power generation element 3. Since stress is applied to the first end portion 6a and the second end portion 6b at the time of cutting, the state of the tissue is changed from the portion between the first end portion 6a and the second end portion 6b. In some cases.
  • the change in the state of the tissue can be one of the factors that make the change in the magnetic flux density unstable.
  • the power generation element 3 receives the magnetic flux from the magnet 2 toward the first end portion 6a.
  • the magnetic flux from the magnet 2 toward the second end 6b is guided to the ferrite beads 8. Since the magnetic permeability of the ferrite beads 8 is higher than the magnetic permeability of the magnetic wire 6, the magnetic flux toward the first end portion 6a and the magnetic flux toward the second end portion 6b can be attracted to the ferrite beads 8.
  • the power generation element 3 does not allow magnetic flux to act on the first end portion 6a and the second end portion 6b, but allows magnetic flux to act on the magnetic wire 6 through the ferrite beads 8.
  • the power generation element 3 can suppress variations in the timing at which magnetization reversal occurs due to the rotation of the magnet 2 and variations in the amount of power generation. As a result, the power generation element 3 can reduce the variation in the timing of power generation each time the magnet 2 rotates, and reduce the variation in the amount of power generation each time the magnet 2 rotates.
  • the power generation element 3 faces the magnet 2 in the direction parallel to the rotation axis 9, and the strong magnetization regions Na1, Na2, Sa1, Sa2 and the weak magnetization regions Nb, Sb
  • the rotation speed detector 1 can suppress the variation in the timing of power generation and the variation in the amount of power generation by providing a cylinder which is a soft magnetic material at both ends of the magnetic wire 6. As described above, the rotation speed detector 1 has an effect that the reliability of the rotation speed detection can be improved.
  • FIG. 4 is a plan view showing a magnet and a power generation element included in the rotation speed detector according to the second embodiment of the present invention.
  • the magnet 2 of the second embodiment is provided with weakly magnetized regions Nb1, Nb2, Sb1, Sb2 at the boundary between the N pole 2N and the S pole 2S.
  • the same components as those in the first embodiment are designated by the same reference numerals, and the configurations different from those in the first embodiment will be mainly described.
  • FIG. 4 shows a view of the magnet 2 and the power generation element 3 in a direction parallel to the rotating shaft 9 and from a side opposite to the shaft 4.
  • the magnet 2 of the second embodiment is a cylindrical body having an opening 11 at the center.
  • the magnet 2 may be a flat plate having a circular shape, as in the case of the first embodiment.
  • the N pole 2N has one strong magnetization region Na which is the first region and two weak magnetization regions Nb1 and Nb2 which are the second regions.
  • the strong magnetization region Na and the weak magnetization regions Nb1 and Nb2 have the same magnetizing direction and different magnetic force strengths.
  • the weakly magnetized regions Nb1 and Nb2 are regions in which the magnetic force is weaker than that of the strongly magnetized region Na. That is, the surface magnetic flux densities of the weakly magnetized regions Nb1 and Nb2 are smaller than the surface magnetic flux densities of the strongly magnetized regions Na.
  • the surface magnetic flux density of the weakly magnetized region Nb1 and the surface magnetic flux density of the weakly magnetized region Nb2 are about the same.
  • the S pole 2S has one strong magnetization region Sa which is the first region and two weak magnetization regions Sb1 and Sb2 which are the second regions.
  • the strong magnetization region Sa and the weak magnetization regions Sb1 and Sb2 have the same magnetizing direction and different magnetic force strengths.
  • the weakly magnetized regions Sb1 and Sb2 are regions in which the magnetic force is weaker than the strongly magnetized region Sa. That is, the surface magnetic flux densities of the weakly magnetized regions Sb1 and Sb2 are smaller than the surface magnetic flux densities of the strongly magnetized regions Sa.
  • the surface magnetic flux density of the weakly magnetized region Sb1 and the surface magnetic flux density of the weakly magnetized region Sb2 are about the same.
  • the boundary between the strongly magnetized regions Na and Sa and the weakly magnetized regions Nb1, Nb2, Sb1 and Sb2 is represented by a solid line.
  • the strong magnetization region Na is provided between the weak magnetization region Nb1 and the weak magnetization region Nb2 in the rotation direction. That is, the weakly magnetized regions Nb1 and Nb2 are arranged so as to sandwich the strongly magnetized region Na.
  • the strong magnetization region Na is arranged at the center of the N pole 2N in the rotation direction.
  • the strong magnetization region Sa is provided between the weak magnetization region Sb1 and the weak magnetization region Sb2 in the rotation direction. That is, the weakly magnetized regions Sb1 and Sb2 are arranged so as to sandwich the strongly magnetized region Sa.
  • the strong magnetization region Sa is arranged at the center of the S pole 2S in the rotation direction.
  • the weakly magnetized region Nb1 and the weakly magnetized region Sb1 are adjacent to each other in the rotation direction.
  • the weakly magnetized region Nb2 and the weakly magnetized region Sb2 are adjacent to each other in the rotation direction.
  • the weakly magnetized regions Nb1, Nb2, Sb1, Sb2 are provided at the boundary between the N pole 2N and the S pole 2S of the magnet 2.
  • the strong magnetization region Na and the weak magnetization region Nb1 and Nb2 of the N pole 2N and the strong magnetization region Sa and the weak magnetization region Sb1 and Sb2 of the S pole 2S are magnetized when the magnet 2 is magnetized. This is achieved by changing the strength of the external magnetic field applied to each region of the magnet 2.
  • the portion of the power generation element 3 between the first end portion 6a and the second end portion 6b faces the weakly magnetized region Nb1 and the weakly magnetized region Sb1.
  • the first end portion 6a faces the strong magnetization region Na.
  • the second end portion 6b faces the strong magnetization region Sa.
  • the range of the strong magnetization region Na in the rotation direction is larger than the range of the combined region of the weak magnetization region Nb1 and the weak magnetization region Sb1 in the rotation direction, and the weak magnetization region Nb2 and the weak magnetization region Sb2 in the rotation direction are formed. Greater than the combined area range.
  • the range of the strong magnetization region Sa in the rotation direction is larger than the range of the combined region of the weak magnetization region Nb1 and the weak magnetization region Sb1 in the rotation direction, and the weak magnetization region Nb2 and the weak magnetization region Sb2 in the rotation direction are combined. Greater than the combined area range.
  • FIG. 5 is a diagram showing an example of the relationship between the rotation angle of the magnet and the magnetic flux density in the rotation speed detector according to the second embodiment.
  • the angle “0 degree” is assumed to be when the magnet 2 is in the state shown in FIG.
  • the horizontal axis of the graph shown in FIG. 5 represents the rotation angle when the magnet 2 is rotated in the counterclockwise direction in FIG.
  • the vertical axis of the graph shown in FIG. 5 represents the magnetic flux density in the magnetic wire 6.
  • the curve M3 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the second embodiment is rotated.
  • the curve M2 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the comparative example is rotated, as in the case of the first embodiment.
  • the magnetic flux density starts to decrease from the maximum value at around 30 degrees and reaches the minimum value at around 150 degrees.
  • the magnetic flux density starts to decrease from the maximum value at around 60 degrees and reaches the minimum value at around 120 degrees.
  • the magnetic flux density decreases in a narrower angle range than in the case of the comparative example. That is, in the case of the second embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
  • the magnetic flux density starts to increase from the minimum value at around 200 degrees and reaches the maximum value at around 340 degrees while rotating the magnet 2 from 180 degrees to 360 degrees. ..
  • the magnetic flux density starts to increase from the minimum value at around 220 degrees and reaches the maximum value at around 310 degrees.
  • the magnetic flux density increases in a narrower angle range than in the case of the comparative example. That is, in the case of the second embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
  • the strong magnetization region Sa reaches the position facing the power generation element 3. Further, by rotating the magnet 2, the strong magnetization region Sa moves away from the position facing the power generation element 3, and the weak magnetization regions Sb2 and Nb2 reach the position facing the power generation element 3. Since the range of the combined weakly magnetized regions Sb2 and Nb2 is smaller than the range of the strongly magnetized region Sa, the magnetic flux density sharply decreases.
  • the change in the magnetic flux density when the magnet 2 rotates from 180 degrees to 360 degrees is the same as the change in the magnetic flux density when the magnet 2 rotates from 0 degrees to 180 degrees, except that the positive and negative of the magnetic flux density are different.
  • the weak magnetization regions Nb1, Nb2, Sb1, Sb2 are provided at the boundary between the N pole 2N and the S pole 2S of the magnet 2, so that the magnetic flux density is reduced while the magnet 2 is rotated once.
  • the angle range to be magnetized and the angle range to increase the magnetic flux density are limited.
  • the angle range in which the magnetization reversal occurs can be limited as compared with the case of the comparative example.
  • the power generation element 3 can suppress variations in the timing of outputting the induced voltage due to the rotation of the magnet 2.
  • the power generation element 3 can reduce variations in power generation timing each time the magnet 2 rotates.
  • the power generation element 3 can increase the amount of power generation as compared with the case of the comparative example because the change in the magnetic flux density with respect to the change in the angle is steep.
  • the rotation speed detector 1 increases the amount of power generation in the power generation element 3 by providing the strong magnetization regions Na and Sa and the weak magnetization regions Nb1, Nb2, Sb1 and Sb2 in the magnet 2. It is possible to suppress variations in the timing of power generation. As a result, the rotation speed detector 1 has the effect of improving the reliability of the rotation speed detection.
  • the strong magnetization regions Na1, Na2, Sa1, Sa2 which are the first regions of the magnet 2 of the first embodiment, the weak magnetization regions Nb and Sb which are the second regions, and the second magnet 2 of the second embodiment.
  • the strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, Sb1, Sb2, which are the second regions, are realized by changing the strength of the external magnetic field applied at the time of magnetization. Not limited to things.
  • the first region and the second region may be realized by the shape of the magnet 2 or the material of the magnet 2. The case where the first region and the second region are realized by the shape of the magnet 2 or the material of the magnet 2 will be described in the third and subsequent embodiments.
  • FIG. 6 is a diagram showing a rotation speed detector according to the third embodiment of the present invention.
  • the rotation speed detector 20 according to the third embodiment has the same configuration as the rotation speed detector 1 according to the first embodiment, except that a magnet 21 is provided instead of the magnet 2 shown in FIG.
  • the same components as those in the first and second embodiments are designated by the same reference numerals, and the configurations different from those of the first and second embodiments will be mainly described. Note that in FIG. 6, the processing unit 5 is not shown.
  • the strong magnetization regions Na1, Na2, Sa1, Sa2, which are the first regions, and the weak magnetization regions Nb, Sb, which are the second regions, have different thicknesses in the direction parallel to the rotation axis 9.
  • the length of the strong magnetization regions Na1, Na2, Sa1, Sa2 in the direction parallel to the rotation axis 9 of the magnet 21 is longer than the length of the weak magnetization regions Nb, Sb in the direction parallel to the rotation axis 9 of the magnet 21. ..
  • the arrangement of the strong magnetization regions Na1, Na2, Sa1, Sa2 and the weak magnetization regions Nb, Sb in the magnet 21 is the same as that of the magnet 2 shown in FIG.
  • the magnet 21 is a deformed cylindrical body so that the thickness differs between the first region and the second region.
  • the magnet 21 may not be provided with the opening 11.
  • the magnet 21 may be a deformed disk so that the thickness differs between the first region and the second region.
  • the first region which is a region having a large total magnetic flux amount
  • the second region which is a region having a small total magnetic flux amount
  • the first region is brought into close contact with the yoke core portion, while a gap is provided between the second region and the yoke core portion. Occurs.
  • the magnet 21 is formed with a first region having a large total magnetic flux amount and a second region having a small total magnetic flux amount.
  • the magnet 21 has the strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, which are the second regions, as in the case of the magnet 2 shown in FIG. , Sb1 and Sb2 may be provided.
  • FIG. 7 is a diagram showing a rotation speed detector according to the fourth embodiment of the present invention.
  • FIG. 8 is a plan view showing a magnet and a power generation element included in the rotation speed detector according to the fourth embodiment.
  • the rotation speed detector 30 according to the fourth embodiment has the same configuration as the rotation speed detector 1 according to the first embodiment, except that a magnet 31 is provided instead of the magnet 2 shown in FIG.
  • the same components as those in the first to third embodiments are designated by the same reference numerals, and the configurations different from those in the first to third embodiments will be mainly described.
  • FIG. 8 shows a view of the magnet 31 and the power generation element 3 from a direction parallel to the rotation axis 9. Note that in FIG. 7, the processing unit 5 is not shown.
  • the strong magnetization regions Na1, Na2, Sa1, Sa2, which are the first regions, and the weakly magnetized regions Nb, Sb, which are the second regions, have different lengths in the radial direction.
  • the lengths of the strong magnetization regions Na1, Na2, Sa1 and Sa2 in the radial direction of the circle centered on the rotation axis 9 of the magnet 31 are the weak magnetization regions in the radial direction of the circle centered on the rotation axis 9 of the magnet 31. It is longer than the length of Nb and Sb.
  • the arrangement of the strongly magnetized regions Na1, Na2, Sa1, Sa2 and the weakly magnetized regions Nb, Sb in the magnet 31 is the same as that of the magnet 2 shown in FIG. In FIG. 8, the boundary between the N pole 2N and the S pole 2S is represented by a solid line.
  • the magnet 31 is a deformed cylindrical body so that the length in the radial direction differs between the first region and the second region.
  • the magnet 31 may not be provided with the opening 11.
  • the magnet 31 may be a deformed disk so that the thickness in the radial direction differs between the first region and the second region.
  • the first region which is a region having a large total magnetic flux amount
  • the second region which is a region having a small total magnetic flux amount
  • the magnet 31 has the strong magnetization regions Na and Sa, which are the first regions
  • FIG. 9 is a diagram showing a rotation speed detector according to a fifth embodiment of the present invention.
  • the rotation speed detector 40 according to the fifth embodiment has the same configuration as the rotation speed detector 1 according to the first embodiment, except that a magnet 41 is provided instead of the magnet 2 shown in FIG.
  • the same components as those in the first to fourth embodiments are designated by the same reference numerals, and the configurations different from those in the first to fourth embodiments will be mainly described. Note that in FIG. 9, the processing unit 5 is not shown.
  • the magnet 41 has a first portion 41a and a second portion 41b, which are portions made of different materials.
  • the first portion 41a constitutes a strong magnetization region Na1, Na2, Sa1, Sa2 which is a first region.
  • the second portion 41b constitutes the weakly magnetized regions Nb and Sb, which are the second regions.
  • As the material of the first portion 41a a material having a higher residual magnetic flux density than the material of the second portion 41b is used.
  • the arrangement of the strong magnetization regions Na1, Na2, Sa1, Sa2 and the weak magnetization regions Nb, Sb in the magnet 41 is the same as that of the magnet 2 shown in FIG.
  • the magnet 41 is a cylindrical body having an opening 11 at the center.
  • the magnet 41 is not limited to a cylindrical body, and may be a disk.
  • the magnet 41 a material having a higher residual magnetic flux density than the material of the second portion 41b is used as the material of the first portion 41a, so that the first region and the total magnetic flux, which are regions where the total magnetic flux amount is large, are used.
  • the magnet 41 has the strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, which are the second regions, as in the case of the magnet 2 shown in FIG. , Sb1 and Sb2 may be provided.
  • the configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

Abstract

A rotation speed detector (1) has: a magnet (2) attached to a shaft (4), which is a rotating body that rotates about a rotation axis (9); and a power generation element (3) that generates an inducement voltage in accordance with a change in a magnetic field produced due to rotation of the magnet (2). The rotation speed detector (1) detects the rotation speed of the rotating body on the basis of the inducement voltage. The power generation element (3) has: a magnetic wire (6); a coil (7) wound between a first end part and a second end part of the magnetic wire (6), these end parts being the two end parts of the magnetic wire (6); and cylindrical ferrite beads (8) that are provided to each of the first end part and the second end part, the ferrite beads (8) being soft magnetic bodies. The magnet (2) has a plurality of magnetic poles arranged in the rotation direction of the magnet (2). Each of the plurality of magnetic poles has a first region and a second region having mutually different strengths of magnetic force.

Description

回転数検出器Rotation speed detector
　本発明は、回転体の回転数を検出する回転数検出器に関する。 The present invention relates to a rotation speed detector that detects the rotation speed of a rotating body.
　回転体に取り付けられる磁石を有し、磁石の回転による磁界の変化にしたがって発生する誘起電圧を基に回転体の回転数を検出する回転数検出器が知られている。特許文献１には、磁界の変化に基づいて大バルクハウゼン効果による磁化反転を生じる磁性ワイヤと、磁性ワイヤに巻回されており磁性ワイヤの磁化反転にしたがって誘起電圧を発生するコイルとを有する回転数検出器が開示されている。 There is known a rotation speed detector that has a magnet attached to a rotating body and detects the rotation speed of the rotating body based on an induced voltage generated according to a change in a magnetic field due to the rotation of the magnet. Patent Document 1 includes a magnetic wire that causes magnetization reversal due to a large bulkhausen effect based on a change in a magnetic field, and a coil that is wound around the magnetic wire and generates an induced voltage according to the magnetization reversal of the magnetic wire. Number detectors are disclosed.
　特許文献１によると、磁性ワイヤおよびコイルが、回転体の回転軸と垂直な方向において磁石と対向することによって、磁性ワイヤの端部と磁石との間隔が、磁性ワイヤの中心部と磁石との間隔よりも長くなる。このため、磁石からの磁束は、磁性ワイヤの中心部よりも磁性ワイヤの端部において弱くなる。大バルクハウゼン効果は磁性ワイヤの端部よりも磁性ワイヤの中心部において安定することから、磁性ワイヤの中心部よりも磁性ワイヤの端部において磁束が弱められることによって、誘起電圧の発生が安定する。これにより、回転数検出器は、発電量のばらつきを低減できる。 According to Patent Document 1, the magnetic wire and the coil face the magnet in the direction perpendicular to the rotation axis of the rotating body, so that the distance between the end of the magnetic wire and the magnet is set between the center of the magnetic wire and the magnet. It will be longer than the interval. Therefore, the magnetic flux from the magnet is weaker at the end of the magnetic wire than at the center of the magnetic wire. Since the large bulkhausen effect is more stable at the center of the magnetic wire than at the end of the magnetic wire, the magnetic flux is weakened at the end of the magnetic wire rather than at the center of the magnetic wire, thereby stabilizing the generation of the induced voltage. .. As a result, the rotation speed detector can reduce the variation in the amount of power generation.
特開２０１８－１８９４２６号公報JP-A-2018-189426
　特許文献１にかかる従来の技術によると、磁性ワイヤの端部において磁束が弱められているため、磁性ワイヤの中心部に作用する磁束と同じ強さの磁束が磁性ワイヤの全体に作用する場合に比べて、発電量が低下する。発電量の低下は、発電量のばらつきと同様、回転数の検出における信頼性の低下を招来する。このように、従来の技術によると、回転数検出器は、発電量のばらつきの低減と発電量の低下の抑制との両立が困難であり、回転数検出の信頼性向上が容易ではなかった。 According to the conventional technique according to Patent Document 1, since the magnetic flux is weakened at the end of the magnetic wire, when a magnetic flux having the same strength as the magnetic flux acting on the central portion of the magnetic wire acts on the entire magnetic wire. In comparison, the amount of power generated is reduced. A decrease in the amount of power generation leads to a decrease in reliability in the detection of the number of revolutions as well as a variation in the amount of power generation. As described above, according to the conventional technique, it is difficult for the rotation speed detector to both reduce the variation in the power generation amount and suppress the decrease in the power generation amount, and it is not easy to improve the reliability of the rotation speed detection.
　本発明は、上記に鑑みてなされたものであって、回転数検出の信頼性を向上可能な回転数検出器を得ることを目的とする。 The present invention has been made in view of the above, and an object of the present invention is to obtain a rotation speed detector capable of improving the reliability of rotation speed detection.
　上述した課題を解決し、目的を達成するために、本発明にかかる回転数検出器は、回転軸を中心に回転する回転体に取り付けられる磁石と、磁石の回転による磁界の変化にしたがって誘起電圧を発生する発電素子とを有し、誘起電圧を基に回転体の回転数を検出する。発電素子は、磁性ワイヤと、磁性ワイヤのうち磁性ワイヤの両端部である第１端部および第２端部の間に巻回されたコイルと、軟磁性体であって第１端部および第２端部の各々に設けられている筒体と、を有する。磁石は、磁石の回転方向に並べられた複数の磁極を有する。複数の磁極の各々は、磁力の強さが互いに異なる第１の領域と第２の領域とを有する。 In order to solve the above-mentioned problems and achieve the object, the rotation speed detector according to the present invention has a magnet attached to a rotating body rotating around a rotation axis and an induced voltage according to a change in a magnetic field due to the rotation of the magnet. It has a power generation element that generates the above, and detects the number of rotations of the rotating body based on the induced voltage. The power generation element includes a magnetic wire, a coil wound between the first end and the second end of the magnetic wire, which are both ends of the magnetic wire, and a soft magnetic material, which is the first end and the first end. It has a cylinder provided at each of the two ends. The magnet has a plurality of magnetic poles arranged in the direction of rotation of the magnet. Each of the plurality of magnetic poles has a first region and a second region in which the strengths of the magnetic forces are different from each other.
　本発明にかかる回転数検出器は、回転数検出の信頼性を向上できるという効果を奏する。 The rotation speed detector according to the present invention has the effect of improving the reliability of rotation speed detection.
本発明の実施の形態１にかかる回転数検出器を示す図The figure which shows the rotation speed detector which concerns on Embodiment 1 of this invention. 実施の形態１にかかる回転数検出器が有する磁石と発電素子とを示す平面図Top view showing a magnet and a power generation element included in the rotation speed detector according to the first embodiment. 実施の形態１にかかる回転数検出器における磁石の回転角度と磁束密度との関係の例を示す図The figure which shows the example of the relationship between the rotation angle of a magnet, and the magnetic flux density in the rotation speed detector which concerns on Embodiment 1. 本発明の実施の形態２にかかる回転数検出器が有する磁石と発電素子とを示す平面図Top view showing a magnet and a power generation element included in the rotation speed detector according to the second embodiment of the present invention. 実施の形態２にかかる回転数検出器における磁石の回転角度と磁束密度との関係の例を示す図The figure which shows the example of the relationship between the rotation angle of a magnet, and the magnetic flux density in the rotation speed detector which concerns on Embodiment 2. 本発明の実施の形態３にかかる回転数検出器を示す図The figure which shows the rotation speed detector which concerns on Embodiment 3 of this invention. 本発明の実施の形態４にかかる回転数検出器を示す図The figure which shows the rotation speed detector which concerns on Embodiment 4 of this invention. 実施の形態４にかかる回転数検出器が有する磁石と発電素子とを示す平面図Top view showing a magnet and a power generation element included in the rotation speed detector according to the fourth embodiment. 本発明の実施の形態５にかかる回転数検出器を示す図The figure which shows the rotation speed detector which concerns on Embodiment 5 of this invention.
　以下に、本発明の実施の形態にかかる回転数検出器を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。 The rotation speed detector according to the embodiment of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to this embodiment.
実施の形態１．
　図１は、本発明の実施の形態１にかかる回転数検出器を示す図である。実施の形態１にかかる回転数検出器１は、磁界の変化にしたがって発生する誘起電圧を基に回転体の回転数を検出する磁気式回転数検出器である。回転数検出器１は、回転体が回転する回数を検出する。 Embodiment 1.
FIG. 1 is a diagram showing a rotation speed detector according to the first embodiment of the present invention. The rotation speed detector 1 according to the first embodiment is a magnetic rotation speed detector that detects the rotation speed of a rotating body based on an induced voltage generated according to a change in a magnetic field. The rotation speed detector 1 detects the number of times the rotating body rotates.
　回転数検出器１は、シャフト４に取り付けられる磁石２と、磁石２の回転による磁界の変化にしたがって誘起電圧を発生して信号を出力する発電素子３と、発電素子３からの信号を処理する処理部５とを有する。磁石２は、円形を呈する平板である。磁石２は、永久磁石である。シャフト４は、回転軸９を中心に回転する回転体である。磁石２は、接着、ねじ止め、あるいは圧入によって、シャフト４の先端に固定されている。シャフト４は、モータの駆動軸である。図１では、シャフト４を回転させるモータ本体の図示を省略する。 The rotation speed detector 1 processes the magnet 2 attached to the shaft 4, the power generation element 3 that generates an induced voltage according to the change in the magnetic field due to the rotation of the magnet 2, and outputs a signal, and the signal from the power generation element 3. It has a processing unit 5. The magnet 2 is a flat plate having a circular shape. The magnet 2 is a permanent magnet. The shaft 4 is a rotating body that rotates around a rotating shaft 9. The magnet 2 is fixed to the tip of the shaft 4 by adhesion, screwing, or press fitting. The shaft 4 is a drive shaft of the motor. In FIG. 1, the motor body that rotates the shaft 4 is not shown.
　処理部５は、発電素子３からの信号を基に、発電によるパルスの数をカウントする。処理部５は、パルスの数をカウントすることによって、シャフト４の回転数を検出する。処理部５は、誘起電圧を利用して動作可能であるため、回転数の検出を無電源で行うことができる。 The processing unit 5 counts the number of pulses generated by power generation based on the signal from the power generation element 3. The processing unit 5 detects the rotation speed of the shaft 4 by counting the number of pulses. Since the processing unit 5 can operate using the induced voltage, the rotation speed can be detected without a power source.
　発電素子３は、回転軸９に平行な方向において磁石２と対向して配置されている。発電素子３は、磁石２のうちシャフト４に固定される側の面とは逆側の表面と対向する。発電素子３は、磁石２のうちシャフト４に固定される側の面と対向して配置されても良い。発電素子３は、磁性ワイヤ６と、磁性ワイヤ６に巻回されたコイル７と、磁性ワイヤ６の両端部である第１端部６ａおよび第２端部６ｂの各々に設けられているフェライトビーズ８とを有する。 The power generation element 3 is arranged to face the magnet 2 in a direction parallel to the rotation axis 9. The power generation element 3 faces the surface of the magnet 2 opposite to the surface fixed to the shaft 4. The power generation element 3 may be arranged so as to face the surface of the magnet 2 on the side fixed to the shaft 4. The power generation element 3 includes a magnetic wire 6, a coil 7 wound around the magnetic wire 6, and ferrite beads provided on each of the first end portion 6a and the second end portion 6b, which are both ends of the magnetic wire 6. Has 8 and.
　磁性ワイヤ６は、ワイヤ状に加工された磁性体である。磁性ワイヤ６は、磁界の変化に基づいて大バルクハウゼン効果による磁化反転を生じる。大バルクハウゼン効果は、磁性体が磁化する際に磁性体内部の磁壁が一度に移動することによって短時間において磁化方向が反転する現象である。 The magnetic wire 6 is a magnetic material processed into a wire shape. The magnetic wire 6 causes magnetization reversal due to the large Barkhausen effect based on the change in the magnetic field. The large Barkhausen effect is a phenomenon in which the magnetization direction is reversed in a short time by moving the domain wall inside the magnetic material at once when the magnetic material is magnetized.
　コイル７は、第１端部６ａおよび第２端部６ｂとの間に巻回されている。すなわち、コイル７は、第１端部６ａに設けられているフェライトビーズ８と第２端部６ｂに設けられているフェライトビーズ８との間に設けられている。コイル７は、ピックアップコイルである。 The coil 7 is wound between the first end portion 6a and the second end portion 6b. That is, the coil 7 is provided between the ferrite beads 8 provided at the first end portion 6a and the ferrite beads 8 provided at the second end portion 6b. The coil 7 is a pickup coil.
　フェライトビーズ８は、軟磁性体の筒体である。フェライトビーズ８の透磁率は、磁性ワイヤ６の透磁率よりも高い。１つのフェライトビーズ８は、第１端部６ａに被せられている。他の１つのフェライトビーズ８は、第２端部６ｂに被せられている。なお、第１端部６ａと第２端部６ｂとに設けられる筒体は、フェライトビーズ８以外の軟磁性体であっても良く、鉄などの軟磁性材料からなる筒体であっても良い。軟磁性体には、フェライトビーズ８以外に、ＳＳ４００またはＳ４５Ｃといった鉄鋼材、ＳＵＳ４３０またはＳＵＳ４４０といった磁性ステンレス鋼材、あるいは、パーマロイまたはパーメンジュールといった高透磁率材などが用いられても良い。発電素子３において２つの軟磁性体の筒体の間隔が広いほど、磁性ワイヤ６の磁化反転領域が増えることによって、発電素子３による発電量が大きくなる。したがって、２つの軟磁性体の筒体のうちの一方は磁性ワイヤ６の一方の端あるいは当該一方の端にできるだけ近い位置に配置され、２つの軟磁性体の筒体のうちの他方は磁性ワイヤ６の他方の端あるいは当該他方の端にできるだけ近い位置に配置されることが望ましい。 Ferrite beads 8 are cylinders made of soft magnetic material. The magnetic permeability of the ferrite beads 8 is higher than the magnetic permeability of the magnetic wire 6. One ferrite bead 8 covers the first end portion 6a. The other ferrite bead 8 covers the second end portion 6b. The cylinder provided at the first end portion 6a and the second end portion 6b may be a soft magnetic material other than the ferrite beads 8, or may be a cylinder made of a soft magnetic material such as iron. .. In addition to the ferrite beads 8, a steel material such as SS400 or S45C, a magnetic stainless steel material such as SUS430 or SUS440, or a high magnetic permeability material such as permalloy or permendur may be used as the soft magnetic material. The wider the distance between the cylinders of the two soft magnetic materials in the power generation element 3, the larger the magnetization reversal region of the magnetic wire 6, and the larger the amount of power generated by the power generation element 3. Therefore, one of the two soft magnetic cylinders is arranged at one end of the magnetic wire 6 or as close as possible to the one end, and the other of the two soft magnetic cylinders is the magnetic wire. It is desirable to place the 6 at the other end or as close as possible to the other end.
　図２は、実施の形態１にかかる回転数検出器が有する磁石と発電素子とを示す平面図である。図２には、回転軸９に平行な方向かつシャフト４とは逆側から磁石２と発電素子３とを見た様子を示している。発電素子３は、磁石２の平面形状である円形の中心から離れた位置において磁石２と対向して配置されている。なお、回転数検出器１は、一般に、回転体の回転角度を検出する角度検出器と併せて使用される。角度検出部は、光学スリットが形成された光学検出用の円板と、光を発生する発光部と、発光部から出射して光学スリットを経由した光を検出する受光部とを備える。例えば、円板は、磁石２の上面側において回転体に固定される。発光部と受光部とは、光学スリットと対向する位置に設けられる。図１および図２では、角度検出部の図示を省略する。 FIG. 2 is a plan view showing a magnet and a power generation element included in the rotation speed detector according to the first embodiment. FIG. 2 shows a view of the magnet 2 and the power generation element 3 in a direction parallel to the rotating shaft 9 and from a side opposite to the shaft 4. The power generation element 3 is arranged so as to face the magnet 2 at a position away from the center of the circular shape of the magnet 2. The rotation speed detector 1 is generally used in combination with an angle detector that detects the rotation angle of the rotating body. The angle detection unit includes an optical detection disk on which an optical slit is formed, a light emitting unit that generates light, and a light receiving unit that emits light from the light emitting unit and detects light that has passed through the optical slit. For example, the disk is fixed to the rotating body on the upper surface side of the magnet 2. The light emitting unit and the light receiving unit are provided at positions facing the optical slit. In FIGS. 1 and 2, the angle detection unit is not shown.
　磁石２は、磁石２の回転方向に並べられた複数の磁極を有する。実施の形態１では、磁石２は、２つの磁極である第１の磁極と第２の磁極とを有する。第１の磁極と第２の磁極とは、着磁方向が互いに異なる２つの磁極である。磁石２は、円の直径を境界として、第１の磁極であるＮ極２Ｎと第２の磁極であるＳ極２Ｓとに２等分されている。磁石２は、回転軸９に平行な方向に着磁されている。 The magnet 2 has a plurality of magnetic poles arranged in the rotation direction of the magnet 2. In the first embodiment, the magnet 2 has two magnetic poles, a first magnetic pole and a second magnetic pole. The first magnetic pole and the second magnetic pole are two magnetic poles having different magnetizing directions. The magnet 2 is bisected into an N pole 2N, which is the first magnetic pole, and an S pole 2S, which is the second magnetic pole, with the diameter of the circle as a boundary. The magnet 2 is magnetized in a direction parallel to the rotation axis 9.
　磁石２は、１対のＮ極２ＮおよびＳ極２Ｓを有するものに限られず、２対以上のＮ極２ＮおよびＳ極２Ｓを有するものであっても良い。すなわち、磁石２は、４つ以上の磁極を有するものであっても良い。また、磁石２は、円形を呈する平板に限られず、中心に開口が設けられた円筒体であっても良い。 The magnet 2 is not limited to one having a pair of N poles 2N and S pole 2S, and may have two or more pairs of N poles 2N and S poles 2S. That is, the magnet 2 may have four or more magnetic poles. Further, the magnet 2 is not limited to a flat plate having a circular shape, and may be a cylindrical body having an opening at the center.
　Ｎ極２Ｎは、第１の領域である２つの強磁化領域Ｎａ１，Ｎａ２と第２の領域である１つの弱磁化領域Ｎｂとを有する。強磁化領域Ｎａ１，Ｎａ２と弱磁化領域Ｎｂとは、着磁方向が互いに同じであって、かつ磁力の強さが互いに異なる。弱磁化領域Ｎｂは、強磁化領域Ｎａ１，Ｎａ２よりも磁力が弱い領域である。すなわち、弱磁化領域Ｎｂの表面磁束密度は、強磁化領域Ｎａ１，Ｎａ２の表面磁束密度よりも小さい。強磁化領域Ｎａ１の表面磁束密度と強磁化領域Ｎａ２の表面磁束密度とは、同程度である。 The N pole 2N has two strongly magnetized regions Na1 and Na2, which are the first regions, and one weakly magnetized region Nb, which is the second region. The strong magnetization regions Na1 and Na2 and the weak magnetization regions Nb have the same magnetizing direction and different magnetic force strengths. The weakly magnetized region Nb is a region having a weaker magnetic force than the strongly magnetized regions Na1 and Na2. That is, the surface magnetic flux density of the weakly magnetized region Nb is smaller than the surface magnetic flux density of the strongly magnetized regions Na1 and Na2. The surface magnetic flux density of the strong magnetization region Na1 and the surface magnetic flux density of the strong magnetization region Na2 are about the same.
　Ｓ極２Ｓは、第１の領域である２つの強磁化領域Ｓａ１，Ｓａ２と第２の領域である１つの弱磁化領域Ｓｂとを有する。強磁化領域Ｓａ１，Ｓａ２と弱磁化領域Ｓｂとは、着磁方向が互いに同じであって、かつ磁力の強さが互いに異なる。弱磁化領域Ｓｂは、強磁化領域Ｓａ１，Ｓａ２よりも磁力が弱い領域である。すなわち、弱磁化領域Ｓｂの表面磁束密度は、強磁化領域Ｓａ１，Ｓａ２の表面磁束密度よりも小さい。強磁化領域Ｓａ１の表面磁束密度と強磁化領域Ｓａ２の表面磁束密度とは、同程度である。なお、図２では、強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と弱磁化領域Ｎｂ，Ｓｂとの各領域の境界を実線で表している。 The S pole 2S has two strongly magnetized regions Sa1 and Sa2, which are the first regions, and one weakly magnetized region Sb, which is the second region. The strongly magnetized regions Sa1 and Sa2 and the weakly magnetized regions Sb have the same magnetizing direction and different magnetic force strengths. The weakly magnetized region Sb is a region having a weaker magnetic force than the strongly magnetized regions Sa1 and Sa2. That is, the surface magnetic flux density of the weakly magnetized region Sb is smaller than the surface magnetic flux density of the strongly magnetized regions Sa1 and Sa2. The surface magnetic flux density of the strong magnetization region Sa1 and the surface magnetic flux density of the strong magnetization region Sa2 are about the same. In FIG. 2, the boundary between the strongly magnetized regions Na1, Na2, Sa1, Sa2 and the weakly magnetized regions Nb and Sb is represented by a solid line.
　弱磁化領域Ｎｂは、回転方向において強磁化領域Ｎａ１と強磁化領域Ｎａ２との間に設けられている。すなわち、弱磁化領域Ｎｂは、回転方向において強磁化領域Ｎａ１，Ｎａ２に挟まれて配置されている。弱磁化領域Ｎｂは、Ｎ極２Ｎのうち回転方向における中心に配置されている。弱磁化領域Ｓｂは、回転方向において強磁化領域Ｓａ１と強磁化領域Ｓａ２との間に設けられている。すなわち、弱磁化領域Ｓｂは、回転方向において強磁化領域Ｓａ１，Ｓａ２に挟まれて配置されている。弱磁化領域Ｓｂは、Ｓ極２Ｓのうち回転方向における中心に配置されている。強磁化領域Ｎａ１と強磁化領域Ｓａ１とは、回転方向において互いに隣り合う。強磁化領域Ｎａ２と強磁化領域Ｓａ２とは、回転方向において互いに隣り合う。 The weak magnetization region Nb is provided between the strong magnetization region Na1 and the strong magnetization region Na2 in the rotation direction. That is, the weakly magnetized region Nb is arranged so as to be sandwiched between the strongly magnetized regions Na1 and Na2 in the rotation direction. The weakly magnetized region Nb is arranged at the center of the N pole 2N in the rotation direction. The weak magnetization region Sb is provided between the strong magnetization region Sa1 and the strong magnetization region Sa2 in the rotation direction. That is, the weakly magnetized region Sb is arranged so as to be sandwiched between the strongly magnetized regions Sa1 and Sa2 in the rotation direction. The weakly magnetized region Sb is arranged at the center of the S pole 2S in the rotation direction. The strong magnetization region Na1 and the strong magnetization region Sa1 are adjacent to each other in the rotation direction. The strong magnetization region Na2 and the strong magnetization region Sa2 are adjacent to each other in the rotation direction.
　このように、強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２は、磁石２のうちＮ極２ＮとＳ極２Ｓとの境界に設けられている。実施の形態１において、Ｎ極２Ｎの強磁化領域Ｎａ１，Ｎａ２および弱磁化領域Ｎｂと、Ｓ極２Ｓの強磁化領域Ｓａ１，Ｓａ２および弱磁化領域Ｓｂとは、磁石２の着磁の際に、磁石２の領域ごとに加えられる外部磁場の強さを変化させることによって実現される。磁石２を着磁する際に使用される着磁ヨークのヨークコア部分には、透磁率が互いに異なる２種類の材料が使用される。 As described above, the strong magnetization regions Na1, Na2, Sa1, and Sa2 are provided at the boundary between the N pole 2N and the S pole 2S in the magnet 2. In the first embodiment, the strong magnetization regions Na1 and Na2 and the weak magnetization region Nb of the N pole 2N and the strong magnetization regions Sa1 and Sa2 and the weak magnetization region Sb of the S pole 2S are magnetized when the magnet 2 is magnetized. This is achieved by changing the strength of the external magnetic field applied to each region of the magnet 2. Two types of materials having different magnetic permeabilitys are used for the yoke core portion of the magnetizing yoke used when magnetizing the magnet 2.
　図２に示す状態において、発電素子３は、強磁化領域Ｎａ１と強磁化領域Ｓａ１とに対向している。回転軸９に平行な方向において磁石２と発電素子３とを平面視した場合において、発電素子３の全体は、強磁化領域Ｎａ１と強磁化領域Ｓａ１とを合わせた領域の中にある。 In the state shown in FIG. 2, the power generation element 3 faces the strong magnetization region Na1 and the strong magnetization region Sa1. When the magnet 2 and the power generation element 3 are viewed in a plane in a direction parallel to the rotation axis 9, the entire power generation element 3 is in a region in which the strong magnetization region Na1 and the strong magnetization region Sa1 are combined.
　図３は、実施の形態１にかかる回転数検出器における磁石の回転角度と磁束密度との関係の例を示す図である。図３において、角度「０度」は、磁石２が図２に示す状態であるときとする。図３に示すグラフの横軸は、図２において反時計回りの方向へ磁石２を回転させた場合における回転角度を表す。図３に示すグラフの縦軸は、磁性ワイヤ６における磁束密度を表す。 FIG. 3 is a diagram showing an example of the relationship between the rotation angle of the magnet and the magnetic flux density in the rotation speed detector according to the first embodiment. In FIG. 3, the angle “0 degree” is assumed to be when the magnet 2 is in the state shown in FIG. The horizontal axis of the graph shown in FIG. 3 represents the rotation angle when the magnet 2 is rotated in the counterclockwise direction in FIG. The vertical axis of the graph shown in FIG. 3 represents the magnetic flux density in the magnetic wire 6.
　曲線Ｍ１は、実施の形態１の磁石２を回転させる場合における角度と磁束密度との関係を表す。曲線Ｍ２は、比較例の磁石２を回転させる場合における角度と磁束密度との関係を表す。比較例の磁石２は、強磁化領域のみからなる１対のＮ極およびＳ極を有するものとする。 The curve M1 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the first embodiment is rotated. The curve M2 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the comparative example is rotated. It is assumed that the magnet 2 of the comparative example has a pair of north and south poles consisting of only a strong magnetization region.
　実施の形態１と比較例とにおいて、角度が０度であるとき、磁束の方向は磁性ワイヤ６の長さ方向と平行である。角度が０度であるときの磁束密度は極大値である。角度が１８０度であるとき、磁束の方向は、角度が０度であるときとは逆の方向となる。角度が１８０度であるときの磁束密度は極小値である。 In the first embodiment and the comparative example, when the angle is 0 degrees, the direction of the magnetic flux is parallel to the length direction of the magnetic wire 6. The magnetic flux density when the angle is 0 degrees is a maximum value. When the angle is 180 degrees, the direction of the magnetic flux is opposite to that when the angle is 0 degrees. The magnetic flux density when the angle is 180 degrees is a minimum value.
　比較例の場合、０度から１８０度まで磁石２を回転させる間に、磁束密度は、３０度付近から１５０度付近までの範囲において一様に減少する。また、１８０度から３６０度まで磁石を回転させる間に、磁束密度は、２１０度付近から３３０度付近までの範囲において一様に増加する。 In the case of the comparative example, the magnetic flux density decreases uniformly in the range of about 30 degrees to about 150 degrees while the magnet 2 is rotated from 0 degrees to 180 degrees. Further, while rotating the magnet from 180 degrees to 360 degrees, the magnetic flux density increases uniformly in the range from around 210 degrees to around 330 degrees.
　実施の形態１の場合、０度から磁石２を回転させていくと、磁束密度は、３０度付近から７０度付近までの範囲において極大値からゼロまで減少する。磁束密度は、７０度付近から１２０度付近までの範囲においてゼロのままとなり、１２０度付近から１６０度付近までの範囲においてゼロから極小値まで減少する。このように、実施の形態１の場合、比較例の場合よりも狭い角度範囲において磁束密度が減少する。すなわち、実施の形態１の場合、比較例の場合よりも、角度の変化に対して磁束密度が急峻に変化する。 In the case of the first embodiment, when the magnet 2 is rotated from 0 degrees, the magnetic flux density decreases from the maximum value to zero in the range from about 30 degrees to about 70 degrees. The magnetic flux density remains zero in the range from around 70 degrees to around 120 degrees, and decreases from zero to the minimum value in the range from around 120 degrees to around 160 degrees. As described above, in the case of the first embodiment, the magnetic flux density decreases in a narrower angle range than in the case of the comparative example. That is, in the case of the first embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
　また、実施の形態１の場合において、１８０度から磁石２を回転させていくと、磁束密度は、２００度付近から２５０度付近までの範囲において極小値からゼロまで増加する。磁束密度は、２５０度付近から３００度付近までの範囲においてゼロのままとなり、３００度付近から３４０度付近までの範囲においてゼロから極大値まで増加する。実施の形態１の場合、比較例の場合よりも狭い角度範囲において磁束密度が増加する。すなわち、実施の形態１の場合、比較例の場合よりも、角度の変化に対して磁束密度が急峻に変化する。 Further, in the case of the first embodiment, when the magnet 2 is rotated from 180 degrees, the magnetic flux density increases from the minimum value to zero in the range from about 200 degrees to about 250 degrees. The magnetic flux density remains zero in the range from around 250 degrees to around 300 degrees and increases from zero to the maximum value in the range from around 300 degrees to around 340 degrees. In the case of the first embodiment, the magnetic flux density increases in a narrower angle range than in the case of the comparative example. That is, in the case of the first embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
　図２に示す状態から磁石２を回転させることによって、第２端部６ｂに対向する位置に弱磁化領域Ｓｂが到達する。さらに磁石２を回転させることによって、発電素子３と対向する位置から強磁化領域Ｎａ１，Ｓａ１は離れていき、発電素子３と対向する位置に弱磁化領域Ｓｂが到達する。発電素子３と対向する位置を弱磁化領域Ｓｂが通過するときにおける磁束密度の変化は、発電素子３と対向する位置を強磁化領域Ｓａ１が通過するときにおける磁束密度の変化よりも小さい。したがって、実施の形態１の場合、９０度を含む角度範囲において磁束密度が変化しない状態となる。その後、さらに磁石２を回転させることによって、弱磁化領域Ｓｂは発電素子３と対向する位置から離れていき、発電素子３と対向する位置に強磁化領域Ｓａ２，Ｎａ２が到達する。発電素子３と対向する位置に強磁化領域Ｓａ２，Ｎａ２が到達することによって、磁束密度は、ゼロから極小値へ急峻に減少する。磁石２が１８０度から３６０度まで回転する場合における磁束密度の変化は、磁束密度の正負が異なる以外は、磁石２が０度から１８０度まで回転する場合における磁束密度の変化と同様である。 By rotating the magnet 2 from the state shown in FIG. 2, the weakly magnetized region Sb reaches a position facing the second end portion 6b. Further, by rotating the magnet 2, the strong magnetization regions Na1 and Sa1 are separated from the position facing the power generation element 3, and the weak magnetization region Sb reaches the position facing the power generation element 3. The change in magnetic flux density when the weakly magnetized region Sb passes through the position facing the power generation element 3 is smaller than the change in magnetic flux density when the strong magnetization region Sa1 passes through the position facing the power generation element 3. Therefore, in the case of the first embodiment, the magnetic flux density does not change in the angle range including 90 degrees. After that, by further rotating the magnet 2, the weakly magnetized region Sb moves away from the position facing the power generation element 3, and the strong magnetization regions Sa2 and Na2 reach the position facing the power generation element 3. When the strong magnetization regions Sa2 and Na2 reach the positions facing the power generation element 3, the magnetic flux density sharply decreases from zero to the minimum value. The change in the magnetic flux density when the magnet 2 rotates from 180 degrees to 360 degrees is the same as the change in the magnetic flux density when the magnet 2 rotates from 0 degrees to 180 degrees, except that the positive and negative of the magnetic flux density are different.
　実施の形態１では、磁石２のうちＮ極２ＮとＳ極２Ｓとの境界に強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２を設けたことによって、磁石２を１回転させる中において、磁束密度が減少する角度範囲と磁束密度が増加する角度範囲とが限定される。実施の形態１では、磁性ワイヤ６における磁化反転は、１２０度付近から１６０度付近までの角度範囲と、２００度付近から２５０度付近までの角度範囲とにおいて生じる。 In the first embodiment, the magnetic flux density is reduced in one rotation of the magnet 2 by providing the strong magnetization regions Na1, Na2, Sa1, and Sa2 at the boundary between the N pole 2N and the S pole 2S of the magnet 2. The angle range to be magnetized and the angle range to increase the magnetic flux density are limited. In the first embodiment, the magnetization reversal in the magnetic wire 6 occurs in an angle range from about 120 degrees to about 160 degrees and an angle range from about 200 degrees to about 250 degrees.
　このように、実施の形態１では、比較例の場合に比べて、磁化反転が起きる角度範囲が限定可能となる。発電素子３は、磁化反転が起きる角度範囲が限定されることで、磁石２の回転によって誘起電圧を出力するタイミングのばらつきを抑制できる。これにより、発電素子３は、磁石２が回転するごとにおける発電のタイミングのばらつきを低減できる。また、発電素子３は、角度の変化に対する磁束密度の変化が急峻であることによって、比較例の場合よりも発電量を増加することができる。 As described above, in the first embodiment, the angle range in which the magnetization reversal occurs can be limited as compared with the case of the comparative example. By limiting the angle range in which the magnetization reversal occurs, the power generation element 3 can suppress variations in the timing of outputting the induced voltage due to the rotation of the magnet 2. As a result, the power generation element 3 can reduce variations in power generation timing each time the magnet 2 rotates. Further, the power generation element 3 can increase the amount of power generation as compared with the case of the comparative example because the change in the magnetic flux density with respect to the change in the angle is steep.
　また、実施の形態１では、回転軸９に平行な方向において発電素子３が磁石２と対向することによって、磁性ワイヤ６の全体に磁石２からの磁束を作用させることができる。このため、発電素子３は、磁性ワイヤ６のうち中心部のみに磁束を作用させる場合と比べて、発電量を増加することができる。 Further, in the first embodiment, the magnetic flux from the magnet 2 can be applied to the entire magnetic wire 6 by the power generation element 3 facing the magnet 2 in the direction parallel to the rotation axis 9. Therefore, the power generation element 3 can increase the amount of power generation as compared with the case where the magnetic flux is applied only to the central portion of the magnetic wire 6.
　磁性ワイヤ６の第１端部６ａと第２端部６ｂとは、磁性ワイヤ６のうち第１端部６ａおよび第２端部６ｂの間の部位に比べて、磁束密度の変化が不安定になり易い。通常、磁性ワイヤ６は、ワイヤ状の材料を発電素子３に適した寸法に切断することによって製造される。第１端部６ａと第２端部６ｂとは、切断時に応力が掛けられていることによって、第１端部６ａおよび第２端部６ｂの間の部位とは組織の状態が変化している場合がある。組織の状態が変化していることは、磁束密度の変化が不安定となる要因の１つとなり得る。 The change in magnetic flux density of the first end portion 6a and the second end portion 6b of the magnetic wire 6 is unstable as compared with the portion of the magnetic wire 6 between the first end portion 6a and the second end portion 6b. Easy to become. Usually, the magnetic wire 6 is manufactured by cutting a wire-like material into a size suitable for the power generation element 3. Since stress is applied to the first end portion 6a and the second end portion 6b at the time of cutting, the state of the tissue is changed from the portion between the first end portion 6a and the second end portion 6b. In some cases. The change in the state of the tissue can be one of the factors that make the change in the magnetic flux density unstable.
　実施の形態１では、軟磁性体であるフェライトビーズ８を第１端部６ａと第２端部６ｂとに被せたことによって、発電素子３は、磁石２から第１端部６ａへ向かう磁束と、磁石２から第２端部６ｂへ向かう磁束とを、フェライトビーズ８へ導く。磁性ワイヤ６の透磁率よりもフェライトビーズ８の透磁率のほうが高いことによって、第１端部６ａへ向かう磁束と第２端部６ｂへ向かう磁束とをフェライトビーズ８へ引き寄せることができる。発電素子３は、第１端部６ａと第２端部６ｂとには磁束を作用させず、フェライトビーズ８を通じて磁性ワイヤ６へ磁束を作用させることが可能となる。発電素子３は、フェライトビーズ８を通じて磁性ワイヤ６へ磁束を作用させることで、磁石２の回転によって磁化反転が生じるタイミングのばらつきと、発電量のばらつきとを抑制できる。これにより、発電素子３は、磁石２が回転するごとにおける発電のタイミングのばらつきの低減と、磁石２が回転するごとにおける発電量のばらつきの低減とが可能となる。 In the first embodiment, by covering the first end portion 6a and the second end portion 6b with the ferrite beads 8 which are soft magnetic materials, the power generation element 3 receives the magnetic flux from the magnet 2 toward the first end portion 6a. , The magnetic flux from the magnet 2 toward the second end 6b is guided to the ferrite beads 8. Since the magnetic permeability of the ferrite beads 8 is higher than the magnetic permeability of the magnetic wire 6, the magnetic flux toward the first end portion 6a and the magnetic flux toward the second end portion 6b can be attracted to the ferrite beads 8. The power generation element 3 does not allow magnetic flux to act on the first end portion 6a and the second end portion 6b, but allows magnetic flux to act on the magnetic wire 6 through the ferrite beads 8. By applying a magnetic flux to the magnetic wire 6 through the ferrite beads 8, the power generation element 3 can suppress variations in the timing at which magnetization reversal occurs due to the rotation of the magnet 2 and variations in the amount of power generation. As a result, the power generation element 3 can reduce the variation in the timing of power generation each time the magnet 2 rotates, and reduce the variation in the amount of power generation each time the magnet 2 rotates.
　実施の形態１によると、回転数検出器１は、回転軸９に平行な方向において磁石２に発電素子３を対向させるとともに、強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と弱磁化領域Ｎｂ，Ｓｂとを磁石２に設けたことによって、発電素子３における発電量を増加させることができ、かつ発電のタイミングのばらつきを抑制できる。また、回転数検出器１は、磁性ワイヤ６の両端部の各々に軟磁性体である筒体を設けたことによって、発電のタイミングのばらつきと発電量のばらつきとを抑制できる。以上により、回転数検出器１は、回転数検出の信頼性を向上できるという効果を奏する。 According to the first embodiment, in the rotation number detector 1, the power generation element 3 faces the magnet 2 in the direction parallel to the rotation axis 9, and the strong magnetization regions Na1, Na2, Sa1, Sa2 and the weak magnetization regions Nb, Sb By providing the magnet 2 with the above, the amount of power generated by the power generation element 3 can be increased, and the variation in the timing of power generation can be suppressed. Further, the rotation speed detector 1 can suppress the variation in the timing of power generation and the variation in the amount of power generation by providing a cylinder which is a soft magnetic material at both ends of the magnetic wire 6. As described above, the rotation speed detector 1 has an effect that the reliability of the rotation speed detection can be improved.
実施の形態２．
　図４は、本発明の実施の形態２にかかる回転数検出器が有する磁石と発電素子とを示す平面図である。実施の形態２の磁石２には、Ｎ極２ＮとＳ極２Ｓとの境界に弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２が設けられている。実施の形態２では、上記の実施の形態１と同一の構成要素には同一の符号を付し、実施の形態１とは異なる構成について主に説明する。図４には、回転軸９に平行な方向かつシャフト４とは逆側から磁石２と発電素子３とを見た様子を示している。実施の形態２の磁石２は、中心に開口１１が設けられた円筒体である。磁石２は、実施の形態１の場合と同様に、円形を呈する平板であっても良い。 Embodiment 2.
FIG. 4 is a plan view showing a magnet and a power generation element included in the rotation speed detector according to the second embodiment of the present invention. The magnet 2 of the second embodiment is provided with weakly magnetized regions Nb1, Nb2, Sb1, Sb2 at the boundary between the N pole 2N and the S pole 2S. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the configurations different from those in the first embodiment will be mainly described. FIG. 4 shows a view of the magnet 2 and the power generation element 3 in a direction parallel to the rotating shaft 9 and from a side opposite to the shaft 4. The magnet 2 of the second embodiment is a cylindrical body having an opening 11 at the center. The magnet 2 may be a flat plate having a circular shape, as in the case of the first embodiment.
　Ｎ極２Ｎは、第１の領域である１つの強磁化領域Ｎａと第２の領域である２つの弱磁化領域Ｎｂ１，Ｎｂ２とを有する。強磁化領域Ｎａと弱磁化領域Ｎｂ１，Ｎｂ２とは、着磁方向が互いに同じであって、かつ磁力の強さが互いに異なる。弱磁化領域Ｎｂ１，Ｎｂ２は、強磁化領域Ｎａよりも磁力が弱い領域である。すなわち、弱磁化領域Ｎｂ１，Ｎｂ２の表面磁束密度は、強磁化領域Ｎａの表面磁束密度よりも小さい。弱磁化領域Ｎｂ１の表面磁束密度と弱磁化領域Ｎｂ２の表面磁束密度とは、同程度である。 The N pole 2N has one strong magnetization region Na which is the first region and two weak magnetization regions Nb1 and Nb2 which are the second regions. The strong magnetization region Na and the weak magnetization regions Nb1 and Nb2 have the same magnetizing direction and different magnetic force strengths. The weakly magnetized regions Nb1 and Nb2 are regions in which the magnetic force is weaker than that of the strongly magnetized region Na. That is, the surface magnetic flux densities of the weakly magnetized regions Nb1 and Nb2 are smaller than the surface magnetic flux densities of the strongly magnetized regions Na. The surface magnetic flux density of the weakly magnetized region Nb1 and the surface magnetic flux density of the weakly magnetized region Nb2 are about the same.
　Ｓ極２Ｓは、第１の領域である１つの強磁化領域Ｓａと第２の領域である２つの弱磁化領域Ｓｂ１，Ｓｂ２とを有する。強磁化領域Ｓａと弱磁化領域Ｓｂ１，Ｓｂ２とは、着磁方向が互いに同じであって、かつ磁力の強さが互いに異なる。弱磁化領域Ｓｂ１，Ｓｂ２は、強磁化領域Ｓａよりも磁力が弱い領域である。すなわち、弱磁化領域Ｓｂ１，Ｓｂ２の表面磁束密度は、強磁化領域Ｓａの表面磁束密度よりも小さい。弱磁化領域Ｓｂ１の表面磁束密度と弱磁化領域Ｓｂ２の表面磁束密度とは、同程度である。なお、図４では、強磁化領域Ｎａ，Ｓａと弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２との各領域の境界を実線で表している。 The S pole 2S has one strong magnetization region Sa which is the first region and two weak magnetization regions Sb1 and Sb2 which are the second regions. The strong magnetization region Sa and the weak magnetization regions Sb1 and Sb2 have the same magnetizing direction and different magnetic force strengths. The weakly magnetized regions Sb1 and Sb2 are regions in which the magnetic force is weaker than the strongly magnetized region Sa. That is, the surface magnetic flux densities of the weakly magnetized regions Sb1 and Sb2 are smaller than the surface magnetic flux densities of the strongly magnetized regions Sa. The surface magnetic flux density of the weakly magnetized region Sb1 and the surface magnetic flux density of the weakly magnetized region Sb2 are about the same. In FIG. 4, the boundary between the strongly magnetized regions Na and Sa and the weakly magnetized regions Nb1, Nb2, Sb1 and Sb2 is represented by a solid line.
　強磁化領域Ｎａは、回転方向において弱磁化領域Ｎｂ１と弱磁化領域Ｎｂ２との間に設けられている。すなわち、弱磁化領域Ｎｂ１，Ｎｂ２は、強磁化領域Ｎａを挟むように配置されている。強磁化領域Ｎａは、Ｎ極２Ｎのうち回転方向における中心に配置されている。強磁化領域Ｓａは、回転方向において弱磁化領域Ｓｂ１と弱磁化領域Ｓｂ２との間に設けられている。すなわち、弱磁化領域Ｓｂ１，Ｓｂ２は、強磁化領域Ｓａを挟むように配置されている。強磁化領域Ｓａは、Ｓ極２Ｓのうち回転方向における中心に配置されている。弱磁化領域Ｎｂ１と弱磁化領域Ｓｂ１とは、回転方向において互いに隣り合う。弱磁化領域Ｎｂ２と弱磁化領域Ｓｂ２とは、回転方向において互いに隣り合う。 The strong magnetization region Na is provided between the weak magnetization region Nb1 and the weak magnetization region Nb2 in the rotation direction. That is, the weakly magnetized regions Nb1 and Nb2 are arranged so as to sandwich the strongly magnetized region Na. The strong magnetization region Na is arranged at the center of the N pole 2N in the rotation direction. The strong magnetization region Sa is provided between the weak magnetization region Sb1 and the weak magnetization region Sb2 in the rotation direction. That is, the weakly magnetized regions Sb1 and Sb2 are arranged so as to sandwich the strongly magnetized region Sa. The strong magnetization region Sa is arranged at the center of the S pole 2S in the rotation direction. The weakly magnetized region Nb1 and the weakly magnetized region Sb1 are adjacent to each other in the rotation direction. The weakly magnetized region Nb2 and the weakly magnetized region Sb2 are adjacent to each other in the rotation direction.
　このように、弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２は、磁石２のうちＮ極２ＮとＳ極２Ｓとの境界に設けられている。実施の形態２において、Ｎ極２Ｎの強磁化領域Ｎａおよび弱磁化領域Ｎｂ１，Ｎｂ２と、Ｓ極２Ｓの強磁化領域Ｓａおよび弱磁化領域Ｓｂ１，Ｓｂ２とは、磁石２の着磁の際に、磁石２の領域ごとに加えられる外部磁場の強さを変化させることによって実現される。 As described above, the weakly magnetized regions Nb1, Nb2, Sb1, Sb2 are provided at the boundary between the N pole 2N and the S pole 2S of the magnet 2. In the second embodiment, the strong magnetization region Na and the weak magnetization region Nb1 and Nb2 of the N pole 2N and the strong magnetization region Sa and the weak magnetization region Sb1 and Sb2 of the S pole 2S are magnetized when the magnet 2 is magnetized. This is achieved by changing the strength of the external magnetic field applied to each region of the magnet 2.
　図４に示す状態において、発電素子３のうち第１端部６ａと第２端部６ｂとの間の部位は、弱磁化領域Ｎｂ１と弱磁化領域Ｓｂ１とに対向している。第１端部６ａは、強磁化領域Ｎａに対向している。第２端部６ｂは、強磁化領域Ｓａに対向している。回転方向における強磁化領域Ｎａの範囲は、回転方向における弱磁化領域Ｎｂ１と弱磁化領域Ｓｂ１とを合わせた領域の範囲よりも大きく、かつ、回転方向における弱磁化領域Ｎｂ２と弱磁化領域Ｓｂ２とを合わせた領域の範囲よりも大きい。回転方向における強磁化領域Ｓａの範囲は、回転方向における弱磁化領域Ｎｂ１と弱磁化領域Ｓｂ１とを合わせた領域の範囲よりも大きく、かつ、回転方向における弱磁化領域Ｎｂ２と弱磁化領域Ｓｂ２とを合わせた領域の範囲よりも大きい。 In the state shown in FIG. 4, the portion of the power generation element 3 between the first end portion 6a and the second end portion 6b faces the weakly magnetized region Nb1 and the weakly magnetized region Sb1. The first end portion 6a faces the strong magnetization region Na. The second end portion 6b faces the strong magnetization region Sa. The range of the strong magnetization region Na in the rotation direction is larger than the range of the combined region of the weak magnetization region Nb1 and the weak magnetization region Sb1 in the rotation direction, and the weak magnetization region Nb2 and the weak magnetization region Sb2 in the rotation direction are formed. Greater than the combined area range. The range of the strong magnetization region Sa in the rotation direction is larger than the range of the combined region of the weak magnetization region Nb1 and the weak magnetization region Sb1 in the rotation direction, and the weak magnetization region Nb2 and the weak magnetization region Sb2 in the rotation direction are combined. Greater than the combined area range.
　図５は、実施の形態２にかかる回転数検出器における磁石の回転角度と磁束密度との関係の例を示す図である。図５において、角度「０度」は、磁石２が図４に示す状態であるときとする。図５に示すグラフの横軸は、図４において反時計回りの方向へ磁石２を回転させた場合における回転角度を表す。図５に示すグラフの縦軸は、磁性ワイヤ６における磁束密度を表す。 FIG. 5 is a diagram showing an example of the relationship between the rotation angle of the magnet and the magnetic flux density in the rotation speed detector according to the second embodiment. In FIG. 5, the angle “0 degree” is assumed to be when the magnet 2 is in the state shown in FIG. The horizontal axis of the graph shown in FIG. 5 represents the rotation angle when the magnet 2 is rotated in the counterclockwise direction in FIG. The vertical axis of the graph shown in FIG. 5 represents the magnetic flux density in the magnetic wire 6.
　曲線Ｍ３は、実施の形態２の磁石２を回転させる場合における角度と磁束密度との関係を表す。曲線Ｍ２は、実施の形態１の場合と同様に、比較例の磁石２を回転させる場合における角度と磁束密度との関係を表す。 The curve M3 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the second embodiment is rotated. The curve M2 represents the relationship between the angle and the magnetic flux density when the magnet 2 of the comparative example is rotated, as in the case of the first embodiment.
　比較例の場合、０度から１８０度まで磁石２を回転させる間において、磁束密度は、３０度付近にて極大値からの減少を開始して、１５０度付近にて極小値に到達する。実施の形態２の場合、磁束密度は、６０度付近にて極大値からの減少を開始して、１２０度付近にて極小値に到達する。このように、実施の形態２の場合、比較例の場合よりも狭い角度範囲において磁束密度が減少する。すなわち、実施の形態２の場合、比較例の場合よりも、角度の変化に対して磁束密度が急峻に変化する。 In the case of the comparative example, while rotating the magnet 2 from 0 degrees to 180 degrees, the magnetic flux density starts to decrease from the maximum value at around 30 degrees and reaches the minimum value at around 150 degrees. In the case of the second embodiment, the magnetic flux density starts to decrease from the maximum value at around 60 degrees and reaches the minimum value at around 120 degrees. As described above, in the case of the second embodiment, the magnetic flux density decreases in a narrower angle range than in the case of the comparative example. That is, in the case of the second embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
　また、比較例の場合、１８０度から３６０度まで磁石２を回転させる間において、磁束密度は、２００度付近にて極小値からの増加を開始して、３４０度付近にて極大値に到達する。実施の形態２の場合、磁束密度は２２０度付近にて極小値からの増加を開始して、３１０度付近にて極大値に到達する。このように、実施の形態２の場合、比較例の場合よりも狭い角度範囲において磁束密度が増加する。すなわち、実施の形態２の場合、比較例の場合よりも、角度の変化に対して磁束密度が急峻に変化する。 Further, in the case of the comparative example, the magnetic flux density starts to increase from the minimum value at around 200 degrees and reaches the maximum value at around 340 degrees while rotating the magnet 2 from 180 degrees to 360 degrees. .. In the case of the second embodiment, the magnetic flux density starts to increase from the minimum value at around 220 degrees and reaches the maximum value at around 310 degrees. As described above, in the case of the second embodiment, the magnetic flux density increases in a narrower angle range than in the case of the comparative example. That is, in the case of the second embodiment, the magnetic flux density changes sharply with the change of the angle as compared with the case of the comparative example.
　図４に示す状態から磁石２を回転させていくと、発電素子３に対向する位置に強磁化領域Ｓａが到達する。さらに磁石２を回転させることによって、強磁化領域Ｓａは発電素子３と対向する位置から離れていき、発電素子３と対向する位置に弱磁化領域Ｓｂ２，Ｎｂ２が到達する。弱磁化領域Ｓｂ２，Ｎｂ２を合わせた領域の範囲が強磁化領域Ｓａの範囲よりも小さいことによって、磁束密度は、急峻に減少する。磁石２が１８０度から３６０度まで回転する場合における磁束密度の変化は、磁束密度の正負が異なる以外は、磁石２が０度から１８０度まで回転する場合における磁束密度の変化と同様である。 When the magnet 2 is rotated from the state shown in FIG. 4, the strong magnetization region Sa reaches the position facing the power generation element 3. Further, by rotating the magnet 2, the strong magnetization region Sa moves away from the position facing the power generation element 3, and the weak magnetization regions Sb2 and Nb2 reach the position facing the power generation element 3. Since the range of the combined weakly magnetized regions Sb2 and Nb2 is smaller than the range of the strongly magnetized region Sa, the magnetic flux density sharply decreases. The change in the magnetic flux density when the magnet 2 rotates from 180 degrees to 360 degrees is the same as the change in the magnetic flux density when the magnet 2 rotates from 0 degrees to 180 degrees, except that the positive and negative of the magnetic flux density are different.
　実施の形態２では、磁石２のうちＮ極２ＮとＳ極２Ｓとの境界に弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２を設けたことによって、磁石２を１回転させる中において、磁束密度が減少する角度範囲と磁束密度が増加する角度範囲とが限定される。このように、実施の形態２では、比較例の場合に比べて、磁化反転が起きる角度範囲が限定可能となる。発電素子３は、磁化反転が起きる角度範囲が限定されることで、磁石２の回転によって誘起電圧を出力するタイミングのばらつきを抑制できる。これにより、発電素子３は、磁石２が回転するごとにおける発電のタイミングのばらつきを低減できる。また、発電素子３は、角度の変化に対する磁束密度の変化が急峻であることによって、比較例の場合よりも発電量を増加することができる。 In the second embodiment, the weak magnetization regions Nb1, Nb2, Sb1, Sb2 are provided at the boundary between the N pole 2N and the S pole 2S of the magnet 2, so that the magnetic flux density is reduced while the magnet 2 is rotated once. The angle range to be magnetized and the angle range to increase the magnetic flux density are limited. As described above, in the second embodiment, the angle range in which the magnetization reversal occurs can be limited as compared with the case of the comparative example. By limiting the angle range in which the magnetization reversal occurs, the power generation element 3 can suppress variations in the timing of outputting the induced voltage due to the rotation of the magnet 2. As a result, the power generation element 3 can reduce variations in power generation timing each time the magnet 2 rotates. Further, the power generation element 3 can increase the amount of power generation as compared with the case of the comparative example because the change in the magnetic flux density with respect to the change in the angle is steep.
　実施の形態２によると、回転数検出器１は、強磁化領域Ｎａ，Ｓａと弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２とを磁石２に設けたことによって、発電素子３における発電量を増加させることができ、かつ発電のタイミングのばらつきを抑制できる。これにより、回転数検出器１は、回転数検出の信頼性を向上できるという効果を奏する。 According to the second embodiment, the rotation speed detector 1 increases the amount of power generation in the power generation element 3 by providing the strong magnetization regions Na and Sa and the weak magnetization regions Nb1, Nb2, Sb1 and Sb2 in the magnet 2. It is possible to suppress variations in the timing of power generation. As a result, the rotation speed detector 1 has the effect of improving the reliability of the rotation speed detection.
　なお、実施の形態１の磁石２における第１の領域である強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２および第２の領域である弱磁化領域Ｎｂ，Ｓｂと、実施の形態２の磁石２における第１の領域である強磁化領域Ｎａ，Ｓａおよび第２の領域である弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２とは、着磁の際に加えられる外部磁場の強さを変化させることによって実現されるものに限られない。第１の領域と第２の領域とは、磁石２の形状あるいは磁石２の材料によって実現されるものでも良い。第１の領域と第２の領域とが磁石２の形状あるいは磁石２の材料によって実現される場合について、実施の形態３以降にて説明する。 The strong magnetization regions Na1, Na2, Sa1, Sa2 which are the first regions of the magnet 2 of the first embodiment, the weak magnetization regions Nb and Sb which are the second regions, and the second magnet 2 of the second embodiment. The strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, Sb1, Sb2, which are the second regions, are realized by changing the strength of the external magnetic field applied at the time of magnetization. Not limited to things. The first region and the second region may be realized by the shape of the magnet 2 or the material of the magnet 2. The case where the first region and the second region are realized by the shape of the magnet 2 or the material of the magnet 2 will be described in the third and subsequent embodiments.
実施の形態３．
　図６は、本発明の実施の形態３にかかる回転数検出器を示す図である。実施の形態３にかかる回転数検出器２０は、図１に示す磁石２に代えて磁石２１が設けられているほかは、実施の形態１にかかる回転数検出器１と同様の構成を有する。実施の形態３では、上記の実施の形態１および２と同一の構成要素には同一の符号を付し、実施の形態１および２とは異なる構成について主に説明する。なお、図６では、処理部５の図示を省略する。 Embodiment 3.
FIG. 6 is a diagram showing a rotation speed detector according to the third embodiment of the present invention. The rotation speed detector 20 according to the third embodiment has the same configuration as the rotation speed detector 1 according to the first embodiment, except that a magnet 21 is provided instead of the magnet 2 shown in FIG. In the third embodiment, the same components as those in the first and second embodiments are designated by the same reference numerals, and the configurations different from those of the first and second embodiments will be mainly described. Note that in FIG. 6, the processing unit 5 is not shown.
　磁石２１において、第１の領域である強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と第２の領域である弱磁化領域Ｎｂ，Ｓｂとでは、回転軸９に平行な方向における厚みが互いに異なる。磁石２１のうち回転軸９に平行な方向における強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２の長さは、磁石２１のうち回転軸９に平行な方向における弱磁化領域Ｎｂ，Ｓｂの長さよりも長い。磁石２１における強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と弱磁化領域Ｎｂ，Ｓｂとの配置は、図２に示す磁石２の場合と同様である。 In the magnet 21, the strong magnetization regions Na1, Na2, Sa1, Sa2, which are the first regions, and the weak magnetization regions Nb, Sb, which are the second regions, have different thicknesses in the direction parallel to the rotation axis 9. The length of the strong magnetization regions Na1, Na2, Sa1, Sa2 in the direction parallel to the rotation axis 9 of the magnet 21 is longer than the length of the weak magnetization regions Nb, Sb in the direction parallel to the rotation axis 9 of the magnet 21. .. The arrangement of the strong magnetization regions Na1, Na2, Sa1, Sa2 and the weak magnetization regions Nb, Sb in the magnet 21 is the same as that of the magnet 2 shown in FIG.
　磁石２１の中心には、開口１１が設けられている。磁石２１は、第１の領域と第２の領域とで厚みを異ならせるように円筒体を変形したものである。なお、磁石２１には、開口１１が設けられていなくても良い。磁石２１は、第１の領域と第２の領域とで厚みを異ならせるように円板を変形したものであっても良い。 An opening 11 is provided in the center of the magnet 21. The magnet 21 is a deformed cylindrical body so that the thickness differs between the first region and the second region. The magnet 21 may not be provided with the opening 11. The magnet 21 may be a deformed disk so that the thickness differs between the first region and the second region.
　磁石２１では、回転軸９に平行な方向における長さを領域ごとに異ならせることによって、総磁束量が多い領域である第１の領域と総磁束量が少ない領域である第２の領域とが形成される。また、第１の領域における磁石２１と発電素子３との距離が、第２の領域における磁石２１と発電素子３との距離よりも短いため、発電素子３に作用する磁力は第２の領域よりも第１の領域において強くなる。磁石２１を着磁する際に使用される着磁ヨークのヨークコア部分が平坦であることによって、第１の領域をヨークコア部分と密着させる一方、第２の領域とヨークコア部分との間には隙間が生じる。これにより、総磁束量が多い第１の領域と総磁束量が少ない第２の領域とが磁石２１に形成される。 In the magnet 21, by making the length in the direction parallel to the rotation axis 9 different for each region, the first region, which is a region having a large total magnetic flux amount, and the second region, which is a region having a small total magnetic flux amount, are separated. It is formed. Further, since the distance between the magnet 21 and the power generation element 3 in the first region is shorter than the distance between the magnet 21 and the power generation element 3 in the second region, the magnetic force acting on the power generation element 3 is smaller than that in the second region. Also becomes stronger in the first area. Since the yoke core portion of the magnetizing yoke used when magnetizing the magnet 21 is flat, the first region is brought into close contact with the yoke core portion, while a gap is provided between the second region and the yoke core portion. Occurs. As a result, the magnet 21 is formed with a first region having a large total magnetic flux amount and a second region having a small total magnetic flux amount.
　なお、実施の形態３では、磁石２１には、図４に示す磁石２の場合と同様に、第１の領域である強磁化領域Ｎａ，Ｓａと第２の領域である弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２とを設けることとしても良い。 In the third embodiment, the magnet 21 has the strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, which are the second regions, as in the case of the magnet 2 shown in FIG. , Sb1 and Sb2 may be provided.
実施の形態４．
　図７は、本発明の実施の形態４にかかる回転数検出器を示す図である。図８は、実施の形態４にかかる回転数検出器が有する磁石と発電素子とを示す平面図である。実施の形態４にかかる回転数検出器３０は、図１に示す磁石２に代えて磁石３１が設けられているほかは、実施の形態１にかかる回転数検出器１と同様の構成を有する。実施の形態４では、上記の実施の形態１から３と同一の構成要素には同一の符号を付し、実施の形態１から３とは異なる構成について主に説明する。図８には、回転軸９に平行な方向から磁石３１と発電素子３とを見た様子を示している。なお、図７では、処理部５の図示を省略する。 Embodiment 4.
FIG. 7 is a diagram showing a rotation speed detector according to the fourth embodiment of the present invention. FIG. 8 is a plan view showing a magnet and a power generation element included in the rotation speed detector according to the fourth embodiment. The rotation speed detector 30 according to the fourth embodiment has the same configuration as the rotation speed detector 1 according to the first embodiment, except that a magnet 31 is provided instead of the magnet 2 shown in FIG. In the fourth embodiment, the same components as those in the first to third embodiments are designated by the same reference numerals, and the configurations different from those in the first to third embodiments will be mainly described. FIG. 8 shows a view of the magnet 31 and the power generation element 3 from a direction parallel to the rotation axis 9. Note that in FIG. 7, the processing unit 5 is not shown.
　磁石３１において、第１の領域である強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と第２の領域である弱磁化領域Ｎｂ，Ｓｂとでは、半径方向における長さが互いに異なる。磁石３１のうち回転軸９を中心とする円の半径方向における強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２の長さは、磁石３１のうち回転軸９を中心とする円の半径方向における弱磁化領域Ｎｂ，Ｓｂの長さよりも長い。磁石３１における強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と弱磁化領域Ｎｂ，Ｓｂとの配置は、図２に示す磁石２の場合と同様である。図８では、Ｎ極２ＮとＳ極２Ｓとの境界を実線で表している。 In the magnet 31, the strong magnetization regions Na1, Na2, Sa1, Sa2, which are the first regions, and the weakly magnetized regions Nb, Sb, which are the second regions, have different lengths in the radial direction. The lengths of the strong magnetization regions Na1, Na2, Sa1 and Sa2 in the radial direction of the circle centered on the rotation axis 9 of the magnet 31 are the weak magnetization regions in the radial direction of the circle centered on the rotation axis 9 of the magnet 31. It is longer than the length of Nb and Sb. The arrangement of the strongly magnetized regions Na1, Na2, Sa1, Sa2 and the weakly magnetized regions Nb, Sb in the magnet 31 is the same as that of the magnet 2 shown in FIG. In FIG. 8, the boundary between the N pole 2N and the S pole 2S is represented by a solid line.
　磁石３１の中心には、開口１１が設けられている。磁石３１は、半径方向における長さを第１の領域と第２の領域とで異ならせるように円筒体を変形したものである。なお、磁石３１には、開口１１が設けられていなくても良い。磁石３１は、半径方向における厚みを第１の領域と第２の領域とで異ならせるように円板を変形したものであっても良い。 An opening 11 is provided at the center of the magnet 31. The magnet 31 is a deformed cylindrical body so that the length in the radial direction differs between the first region and the second region. The magnet 31 may not be provided with the opening 11. The magnet 31 may be a deformed disk so that the thickness in the radial direction differs between the first region and the second region.
　磁石３１では、半径方向における長さを領域ごとに異ならせることによって、総磁束量が多い領域である第１の領域と総磁束量が少ない領域である第２の領域とが形成される。なお、実施の形態４では、磁石３１には、図４に示す磁石２の場合と同様に、第１の領域である強磁化領域Ｎａ，Ｓａと第２の領域である弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２とを設けることとしても良い。 In the magnet 31, the first region, which is a region having a large total magnetic flux amount, and the second region, which is a region having a small total magnetic flux amount, are formed by making the length in the radial direction different for each region. In the fourth embodiment, the magnet 31 has the strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, which are the second regions, as in the case of the magnet 2 shown in FIG. , Sb1 and Sb2 may be provided.
実施の形態５．
　図９は、本発明の実施の形態５にかかる回転数検出器を示す図である。実施の形態５にかかる回転数検出器４０は、図１に示す磁石２に代えて磁石４１が設けられているほかは、実施の形態１にかかる回転数検出器１と同様の構成を有する。実施の形態５では、上記の実施の形態１から４と同一の構成要素には同一の符号を付し、実施の形態１から４とは異なる構成について主に説明する。なお、図９では、処理部５の図示を省略する。 Embodiment 5.
FIG. 9 is a diagram showing a rotation speed detector according to a fifth embodiment of the present invention. The rotation speed detector 40 according to the fifth embodiment has the same configuration as the rotation speed detector 1 according to the first embodiment, except that a magnet 41 is provided instead of the magnet 2 shown in FIG. In the fifth embodiment, the same components as those in the first to fourth embodiments are designated by the same reference numerals, and the configurations different from those in the first to fourth embodiments will be mainly described. Note that in FIG. 9, the processing unit 5 is not shown.
　磁石４１は、互いに異なる材料からなる部位である第１の部位４１ａと第２の部位４１ｂとを有する。第１の部位４１ａは、第１の領域である強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２を構成する。第２の部位４１ｂは、第２の領域である弱磁化領域Ｎｂ，Ｓｂを構成する。第１の部位４１ａの材料には、第２の部位４１ｂの材料よりも残留磁束密度が高い材料が使用されている。磁石４１における強磁化領域Ｎａ１，Ｎａ２，Ｓａ１，Ｓａ２と弱磁化領域Ｎｂ，Ｓｂとの配置は、図２に示す磁石２の場合と同様である。磁石４１は、中心に開口１１が設けられた円筒体である。磁石４１は、円筒体に限られず、円板であっても良い。 The magnet 41 has a first portion 41a and a second portion 41b, which are portions made of different materials. The first portion 41a constitutes a strong magnetization region Na1, Na2, Sa1, Sa2 which is a first region. The second portion 41b constitutes the weakly magnetized regions Nb and Sb, which are the second regions. As the material of the first portion 41a, a material having a higher residual magnetic flux density than the material of the second portion 41b is used. The arrangement of the strong magnetization regions Na1, Na2, Sa1, Sa2 and the weak magnetization regions Nb, Sb in the magnet 41 is the same as that of the magnet 2 shown in FIG. The magnet 41 is a cylindrical body having an opening 11 at the center. The magnet 41 is not limited to a cylindrical body, and may be a disk.
　磁石４１では、第１の部位４１ａの材料に、第２の部位４１ｂの材料よりも残留磁束密度が高い材料が使用されることによって、総磁束量が多い領域である第１の領域と総磁束量が少ない領域である第２の領域とが形成される。なお、実施の形態５では、磁石４１には、図４に示す磁石２の場合と同様に、第１の領域である強磁化領域Ｎａ，Ｓａと第２の領域である弱磁化領域Ｎｂ１，Ｎｂ２，Ｓｂ１，Ｓｂ２とを設けることとしても良い。 In the magnet 41, a material having a higher residual magnetic flux density than the material of the second portion 41b is used as the material of the first portion 41a, so that the first region and the total magnetic flux, which are regions where the total magnetic flux amount is large, are used. A second region, which is a region with a small amount, is formed. In the fifth embodiment, the magnet 41 has the strong magnetization regions Na and Sa, which are the first regions, and the weak magnetization regions Nb1, Nb2, which are the second regions, as in the case of the magnet 2 shown in FIG. , Sb1 and Sb2 may be provided.
　以上の実施の形態に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、本発明の要旨を逸脱しない範囲で、構成の一部を省略、変更することも可能である。 The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations without departing from the gist of the present invention. It is also possible to omit or change the part.
　１，２０，３０，４０　回転数検出器、２，２１，３１，４１　磁石、２Ｎ　Ｎ極、２Ｓ　Ｓ極、３　発電素子、４　シャフト、５　処理部、６　磁性ワイヤ、６ａ　第１端部、６ｂ　第２端部、７　コイル、８　フェライトビーズ、９　回転軸、１１　開口、４１ａ　第１の部位、４１ｂ　第２の部位、Ｎａ，Ｎａ１，Ｎａ２，Ｓａ，Ｓａ１，Ｓａ２　強磁化領域、Ｎｂ，Ｎｂ１，Ｎｂ２，Ｓｂ，Ｓｂ１，Ｓｂ２　弱磁化領域。 1,20,30,40 rotation number detector, 2,21,31,41 magnet, 2N N pole, 2S S pole, 3 power generation element, 4 shaft, 5 processing unit, 6 magnetic wire, 6a 1st end, 6b 2nd end, 7 coil, 8 ferrite beads, 9 rotating shaft, 11 opening, 41a 1st part, 41b 2nd part, Na, Na1, Na2, Sa, Sa1, Sa2 strong magnetization region, Nb, Nb1 , Nb2, Sb, Sb1, Sb2 Weakly magnetized region.

Claims (10)

  1. 　回転軸を中心に回転する回転体に取り付けられる磁石と、前記磁石の回転による磁界の変化にしたがって誘起電圧を発生する発電素子とを有し、前記誘起電圧を基に前記回転体の回転数を検出する回転数検出器であって、
    　前記発電素子は、磁性ワイヤと、前記磁性ワイヤのうち前記磁性ワイヤの両端部である第１端部および第２端部の間に巻回されたコイルと、軟磁性体であって前記第１端部および前記第２端部の各々に設けられている筒体と、を有し、
    　前記磁石は、前記磁石の回転方向に並べられた複数の磁極を有し、
    　前記複数の磁極の各々は、磁力の強さが互いに異なる第１の領域と第２の領域とを有することを特徴とする回転数検出器。     It has a magnet attached to a rotating body that rotates around a rotating shaft, and a power generation element that generates an induced voltage according to a change in the magnetic field due to the rotation of the magnet, and the number of rotations of the rotating body is determined based on the induced voltage. It is a rotation speed detector to detect
    The power generation element is a magnetic wire, a coil wound between the first end and the second end of the magnetic wire, which are both ends of the magnetic wire, and the first soft magnetic material. It has a cylinder provided at each of the end portion and the second end portion, and has.
    The magnet has a plurality of magnetic poles arranged in the direction of rotation of the magnet.
    A rotation speed detector, wherein each of the plurality of magnetic poles has a first region and a second region having different magnetic force strengths.
  2. 　前記発電素子は、前記回転軸に平行な方向において前記磁石と対向していることを特徴とする請求項１に記載の回転数検出器。 The rotation speed detector according to claim 1, wherein the power generation element faces the magnet in a direction parallel to the rotation axis.
  3. 　前記複数の磁極は、着磁方向が互いに異なる第１の磁極および第２の磁極を含み、
    　前記第２の領域は、前記第１の領域よりも磁力が弱く、かつ前記回転方向において前記第１の領域に挟まれて配置され、
    　前記第１の磁極の前記第１の領域と前記第２の磁極の前記第１の領域とは、前記回転方向において互いに隣り合うことを特徴とする請求項１または２に記載の回転数検出器。     The plurality of magnetic poles include a first magnetic pole and a second magnetic pole having different magnetizing directions.
    The second region has a weaker magnetic force than the first region, and is arranged so as to be sandwiched between the first regions in the rotation direction.
    The rotation speed detector according to claim 1 or 2, wherein the first region of the first magnetic pole and the first region of the second magnetic pole are adjacent to each other in the rotation direction. ..
  4. 　前記第１の磁極の前記第１の領域と前記第２の磁極の前記第１の領域とに前記発電素子が対向する状態において、前記回転軸に平行な方向において前記磁石と前記発電素子とを平面視した場合に、前記発電素子の全体は、前記第１の磁極の前記第１の領域と前記第２の磁極の前記第１の領域とを合わせた領域の中にあることを特徴とする請求項３に記載の回転数検出器。 In a state where the power generation element faces the first region of the first magnetic pole and the first region of the second magnetic pole, the magnet and the power generation element are placed in a direction parallel to the rotation axis. When viewed in a plan view, the entire power generation element is in a region in which the first region of the first magnetic pole and the first region of the second magnetic pole are combined. The rotation speed detector according to claim 3.
  5. 　複数の磁極は、着磁方向が互いに異なる第１の磁極および第２の磁極を含み、
    　前記第２の領域は、前記第１の領域よりも磁力が弱く、かつ前記回転方向において前記第１の領域を挟むように配置され、
    　前記第１の磁極の前記第２の領域と前記第２の磁極の前記第２の領域とは、前記回転方向において互いに隣り合うことを特徴とする請求項１または２に記載の回転数検出器。     The plurality of magnetic poles include a first magnetic pole and a second magnetic pole having different magnetizing directions.
    The second region has a weaker magnetic force than the first region, and is arranged so as to sandwich the first region in the rotation direction.
    The rotation speed detector according to claim 1 or 2, wherein the second region of the first magnetic pole and the second region of the second magnetic pole are adjacent to each other in the rotation direction. ..
  6. 　前記回転方向における前記第１の磁極の前記第１の領域の範囲と、前記回転方向における前記第２の磁極の前記第１の領域の範囲との各々は、前記回転方向における前記第１の磁極の前記第２の領域と前記第２の磁極の前記第２の領域とを合わせた領域の範囲よりも大きいことを特徴とする請求項５に記載の回転数検出器。 Each of the range of the first region of the first magnetic pole in the rotation direction and the range of the first region of the second magnetic pole in the rotation direction are the first magnetic pole in the rotation direction. The rotation speed detector according to claim 5, wherein the second region is larger than the range of the combined region of the second region of the second magnetic pole.
  7. 　前記筒体の透磁率は、前記磁性ワイヤの透磁率よりも高いことを特徴とする請求項１から６のいずれか１つに記載の回転数検出器。 The rotation speed detector according to any one of claims 1 to 6, wherein the magnetic permeability of the cylinder is higher than the magnetic permeability of the magnetic wire.
  8. 　前記磁石のうち前記回転軸に平行な方向における前記第１の領域の長さは、前記磁石のうち前記回転軸に平行な方向における前記第２の領域の長さよりも長いことを特徴とする請求項１から６のいずれか１つに記載の回転数検出器。 A claim characterized in that the length of the first region of the magnet in a direction parallel to the rotation axis is longer than the length of the second region of the magnet in a direction parallel to the rotation axis. Item 4. The rotation speed detector according to any one of Items 1 to 6.
  9. 　前記磁石のうち前記回転軸を中心とする円の半径方向における前記第１の領域の長さは、前記磁石のうち前記回転軸を中心とする円の半径方向における前記第２の領域の長さよりも長いことを特徴とする請求項１から６のいずれか１つに記載の回転数検出器。 The length of the first region of the magnet in the radial direction of the circle centered on the rotation axis is greater than the length of the second region of the magnet in the radial direction of the circle centered on the rotation axis. The rotation speed detector according to any one of claims 1 to 6, wherein the rotation speed detector is also long.
  10. 　前記磁石のうち前記第１の領域を構成する部位の材料には、前記磁石のうち前記第２の領域を構成する部位の材料よりも残留磁束密度が高い材料が使用されていることを特徴とする請求項１から６のいずれか１つに記載の回転数検出器。 The material of the portion of the magnet that constitutes the first region is characterized in that a material having a higher residual magnetic flux density than the material of the portion of the magnet that constitutes the second region is used. The rotation speed detector according to any one of claims 1 to 6.
PCT/JP2019/023729 2019-06-14 2019-06-14 Rotation speed detector WO2020250439A1 (en)

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