WO2020027273A1 - Load detector for actuator - Google Patents

Load detector for actuator Download PDF

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Publication number
WO2020027273A1
WO2020027273A1 PCT/JP2019/030261 JP2019030261W WO2020027273A1 WO 2020027273 A1 WO2020027273 A1 WO 2020027273A1 JP 2019030261 W JP2019030261 W JP 2019030261W WO 2020027273 A1 WO2020027273 A1 WO 2020027273A1
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WO
WIPO (PCT)
Prior art keywords
shaft
axis direction
work
strain gauge
motor
Prior art date
Application number
PCT/JP2019/030261
Other languages
French (fr)
Japanese (ja)
Inventor
林　茂樹
克也 福島
正志 石井
弘樹 丹羽
鈴木　明
和人 大賀
翔悟 和久田
聡史 原
智史 水野
Original Assignee
Thk株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thk株式会社 filed Critical Thk株式会社
Publication of WO2020027273A1 publication Critical patent/WO2020027273A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/06—Gripping heads and other end effectors with vacuum or magnetic holding means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes

Definitions

  • the present invention relates to a load detector for an actuator.
  • the work can be sucked to the shaft and the work can be picked up.
  • the work may vigorously collide with the shaft and be damaged, or the work may not be sucked.
  • the load pressing the work is too large, the work may be damaged. Therefore, it is desired to press the shaft against the work with an appropriate load.
  • the speed of the shaft is high when the shaft contacts the work, the work may be damaged by the collision of the shaft with the work. Therefore, it is desired to reduce the impact.
  • a suction member is provided at the tip of a shaft main body via a buffer member such as a spring (for example, see Patent Document 1). That is, when the suction member comes into contact with the work, the spring is contracted to reduce the impact. Thereafter, when the shaft further moves toward the work, the work is pressed with a load corresponding to the spring constant.
  • a buffer member such as a spring
  • the appropriate load may differ depending on the work.However, when the cushioning member as described above is provided, the load applied to the work is determined by the spring constant, so it is difficult to change the load applied to the work according to the work. there were. When adjusting the load applied to the work in such a configuration, for example, it is necessary to replace the buffer member. Further, in the case where the buffer member as described above is provided, the load applied to the work tends to vary, so that it is difficult to use the work for a work that requires a high-precision load adjustment. Here, if the load applied to the shaft and the work can be detected, the shaft can be controlled according to the detected load.
  • the present invention has been made in view of the various circumstances as described above, and an object of the present invention is to detect a load applied to a shaft and a work.
  • One aspect of the present invention is a linear motor having a shaft, a support portion rotatably supporting the shaft, and a stator and a mover, wherein the linear motor has a position relative to the stator.
  • a linear motor that moves the support section and the shaft in the direction of the central axis of the shaft by moving the mover in parallel with the central axis of the shaft;
  • a connection member that is at least a part of a member that connects the first and second portions, and a load detector that detects a force applied to the shaft in an actuator including: a strainer that is provided on the connection member and detects a strain of the connection member. It is a load detector provided with a gauge.
  • the load applied to the shaft and the work can be detected.
  • FIG. 2 is an external view of an actuator according to the embodiment.
  • FIG. 1 is a schematic configuration diagram illustrating an internal structure of an actuator according to an embodiment. It is sectional drawing which showed schematic structure of the shaft housing which concerns on embodiment, and the front-end
  • the support and the shaft are moved in the moving direction of the mover by the linear motor. Since the moving direction of the mover of the linear motor is parallel to the central axis direction of the shaft, the shaft moves in the central axis direction by driving the linear motor.
  • the linear motor is, for example, a linear motor.
  • the support portion is, for example, a rotation motor for rotating a shaft, or a bearing provided between a stator of the rotation motor and an output shaft of the rotation motor.
  • the mover of the linear motion motor is connected to the support via a connecting member. Note that a plurality of connection members may exist.
  • the mover of the linear motion motor and the connection member may be integrated, or the support portion and the connection member may be integrated.
  • the support portion rotatably supports the shaft regardless of the driving of the linear motor. Therefore, it is possible to individually move the shaft in the central axis direction and rotate the shaft around the central axis by the linear motion motor. When picking up the work, the linear motion motor moves the shaft until the shaft contacts the work.
  • connection member has a first member and a second member that are provided to be shifted in a direction of the central axis of the shaft, and the strain gauge is provided in each of the first member and the second member.
  • the shafts may be provided on surfaces parallel to each other in the same direction and orthogonal to the central axis of the shaft.
  • ⁇ when the linear motor operates, heat is generated. Also, other devices provided in the actuator may generate heat. Due to such heat, the linear motion motor, the support portion, and the connection member may thermally expand. In this case, even if no load is applied to the shaft from the workpiece, distortion may occur in the first member and the second member. For example, if there is a temperature difference between a member to which one end of the first member and the second member is connected and a member to which the other end is connected, a difference may occur in the amount of expansion. In the following, a member to which one end of the first member and the second member is connected is described as a member having a large amount of expansion due to heat (a high expansion member), and a member to which the other end is connected is heat.
  • one of the strain gauge provided on the first member and the strain gauge provided on the second member has an output corresponding to the strain in the contracting direction and the other has an output corresponding to the strain in the extending direction. do.
  • the output of one strain gauge and the output of the other strain gauge are positive or negative.
  • the absolute amount is almost the same. Therefore, by connecting the outputs of the two strain gauges in parallel, the effects of thermal expansion are canceled each other, so that it is not necessary to separately perform correction according to the temperature. That is, it is possible to simply and accurately detect only the load applied to the shaft and the work.
  • the strain gauge provided on the first member and the strain gauge provided on the second member may be incorporated in different Wheatstone bridge circuits, respectively, and outputs of both Wheatstone bridge circuits may be connected in parallel. .
  • the effect of heat on the outputs of both strain gauges is canceled out, and the final output is an output corresponding to the load generated between the shaft and the work.
  • the support portion is a rotary motor having a stator and a rotor, and the rotor connected to the shaft rotates with respect to the stator of the rotary motor, thereby rotating the shaft.
  • a rotation motor that rotates around the central axis of the shaft, wherein the first member and the second member are two arms that connect the mover of the linear motion motor and the stator of the rotation motor.
  • the supporting portion may be a bearing provided between the stator of the rotary motor and the output shaft of the rotary motor.
  • the connecting member is a member (for example, a stator of the rotary motor) in contact with the bearing. It may be
  • FIG. 1 is an external view of an actuator 1 according to the present embodiment.
  • the actuator 1 has a housing 2 having a substantially rectangular parallelepiped outer shape, and a lid 200 is attached to the housing 2.
  • FIG. 2 is a schematic configuration diagram illustrating an internal structure of the actuator 1 according to the present embodiment.
  • a part of the shaft 10 is housed inside the housing 2.
  • the tip 10A side of the shaft 10 is formed to be hollow.
  • a material of the shaft 10 and the housing 2 for example, a metal (for example, aluminum) can be used, but a resin or the like can also be used.
  • an XYZ rectangular coordinate system is set, and the position of each member will be described with reference to the XYZ rectangular coordinate system.
  • the long side direction of the largest surface of the housing 2 and the direction of the central axis 100 of the shaft 10 are defined as the Z-axis direction
  • the short side direction of the largest surface of the housing 2 is defined as the X-axis direction
  • the direction perpendicular to the direction is defined as a Y-axis direction.
  • the Z-axis direction is also the vertical direction.
  • the upper side in the Z-axis direction in FIG. 2 is referred to as the upper side of the actuator 1, and the lower side in the Z-axis direction in FIG.
  • the right side in the X-axis direction in FIG. 2 is the right side of the actuator 1, and the left side in the X-axis direction in FIG.
  • the housing 2 is the near side of the actuator 1, and the far side in the Y-axis direction in FIG.
  • the housing 2 has a dimension in the Z-axis direction longer than a dimension in the X-axis direction, and a dimension in the X-axis direction is longer than a dimension in the Y-axis direction.
  • the housing 2 has an opening at a position corresponding to one surface (a surface on the near side in FIG. 2) orthogonal to the Y-axis direction, and this opening is closed by a lid 200.
  • the lid 200 is fixed to the housing 2 by, for example, screws.
  • a rotation motor 20 for rotating the shaft 10 around its central axis 100, and the shaft 10 in a direction along the central axis 100 (that is, the Z-axis direction) relative to the housing 2.
  • the linear motion motor 30 to be moved and the air control mechanism 60 are accommodated.
  • a shaft housing 50 into which the shaft 10 is inserted is attached to a lower end surface 202 of the housing 2 in the Z-axis direction.
  • the housing 2 has a recess 202B formed so as to be recessed from the lower end surface 202 toward the inside of the housing 2, and a part of the shaft housing 50 is inserted into the recess 202B.
  • a through-hole 2A is formed at the upper end of the concave portion 202B in the Z-axis direction in the Z-axis direction, and the shaft 10 is inserted through the through-hole 2A and the shaft housing 50.
  • a lower end portion 10A of the shaft 10 on the lower side in the Z-axis direction projects from the shaft housing 50 to the outside.
  • the shaft 10 is provided at the center of the housing 2 in the X-axis direction and the center of the housing 2 in the Y-axis direction. That is, the shaft 10 is provided such that the center axis of the housing 2 extending in the Z-axis direction through the center in the X-axis direction and the center in the Y-axis direction and the center axis 100 of the shaft 10 overlap.
  • the shaft 10 is linearly moved in the Z-axis direction by a linear motor 30 and is rotated around a central axis 100 by a rotary motor 20.
  • a base end 10B side of the shaft 10 opposite to the front end 10A (the upper end in the Z-axis direction) is housed in the housing 2 and connected to the output shaft 21 of the rotary motor 20.
  • the rotary motor 20 rotatably supports the shaft 10.
  • the center axis of the output shaft 21 of the rotary motor 20 matches the center axis 100 of the shaft 10.
  • the rotary motor 20 includes, in addition to the output shaft 21, a stator 22, a rotor 23 that rotates inside the stator 22, and a rotary encoder 24 that detects a rotation angle of the output shaft 21.
  • the output shaft 21 and the shaft 10 also rotate in conjunction with the stator 22.
  • the linear motor 30 has a stator 31 fixed to the housing 2 and a mover 32 that moves in the Z-axis direction relative to the stator 31.
  • the linear motor 30 is, for example, a linear motor.
  • the stator 31 is provided with a plurality of coils 31A
  • the mover 32 is provided with a plurality of permanent magnets 32A.
  • the coils 31A are arranged at a predetermined pitch in the Z-axis direction, and a plurality of coils 31A of the U, V, and W phases are provided as a set.
  • a moving magnetic field that moves linearly is generated by passing a three-phase armature current through the U, V, and W phase coils 31A, and the mover 32 is moved linearly with respect to the stator 31.
  • Move to The linear motor 30 is provided with a linear encoder 38 for detecting the relative position of the mover 32 with respect to the stator 31.
  • a permanent magnet may be provided on the stator 31 and a plurality of coils may be provided on the mover 32.
  • the mover 32 of the linear motor 30 and the stator 22 of the rotary motor 20 are connected via a linear table 33.
  • the translation table 33 is movable with the movement of the mover 32 of the translation motor 30.
  • the translation table 33 is guided by the translation guide device 34 in the Z-axis direction.
  • the linear motion guide device 34 has a rail 34A fixed to the housing 2 and a slider block 34B assembled to the rail 34A.
  • the rail 34A extends in the Z-axis direction, and the slider block 34B is configured to be movable in the Z-axis direction along the rail 34A.
  • the linear motion table 33 is fixed to the slider block 34B, and is movable in the Z-axis direction together with the slider block 34B.
  • the translation table 33 is connected to the mover 32 of the translation motor 30 via two connection arms 35.
  • the two connecting arms 35 connect both ends of the mover 32 in the Z-axis direction and both ends of the linear motion table 33 in the Z-axis direction.
  • the linear motion table 33 is connected to the stator 22 of the rotary motor 20 via two connection arms 36 on the center side of both ends.
  • the upper connecting arm 36 in the Z-axis direction is referred to as a first arm 36A
  • the lower connecting arm 36 in the Z-axis direction is referred to as a second arm 36B.
  • the connecting arm 36 has a square cross section.
  • a strain gauge 37 is fixed to a surface of each connecting arm 36 facing upward in the Z-axis direction.
  • the strain gauge 37 fixed to the first arm 36A is called a first strain gauge 37A
  • the strain gauge 37 fixed to the second arm 36B is called a second strain gauge 37B.
  • strain gauges 37 When the first strain gauge 37A and the second strain gauge 37B are not distinguished, they are simply referred to as strain gauges 37.
  • the two strain gauges 37 of the present embodiment are respectively provided on the surfaces of the connection arms 36 that face upward in the Z-axis direction. Instead, the two strain gauges 37 face downward of the connection arms 36 in the Z-axis direction. Each may be provided on the surface.
  • the air control mechanism 60 is a mechanism for generating a positive pressure or a negative pressure at the tip 10A of the shaft 10. That is, the air control mechanism 60 generates a negative pressure at the distal end portion 10A of the shaft 10 by sucking the air in the shaft 10 when the work W is picked up. Thereby, the work W is sucked to the tip portion 10A of the shaft 10. Further, by sending air into the shaft 10, a positive pressure is generated at the distal end 10 ⁇ / b> A of the shaft 10. Thereby, the work W is easily detached from the tip portion 10A of the shaft 10.
  • the air control mechanism 60 includes a positive pressure passage 61A (see a dashed line) through which positive-pressure air flows, a negative pressure passage 61B (see a two-dot chain line) through which negative-pressure air flows, and positive-pressure air and air. And a shared passage 61C (see broken line) shared by the negative pressure air.
  • One end of the positive pressure passage 61A is connected to a positive pressure connector 62A provided on the upper end surface 201 in the Z-axis direction of the housing 2, and the other end of the positive pressure passage 61A is connected to a positive pressure solenoid valve (hereinafter, a positive pressure solenoid valve). 63A).
  • the positive pressure solenoid valve 63A is opened and closed by a controller 7 described later.
  • the positive pressure connector 62A passes through the upper end surface 201 of the housing 2 in the Z-axis direction, and a tube connected to a pump or the like that discharges air is connected to the positive pressure connector 62A from the outside.
  • One end of the negative pressure passage 61B is connected to a negative pressure connector 62B provided on the upper end surface 201 in the Z-axis direction of the housing 2, and the other end of the negative pressure passage 61B is connected to a negative pressure solenoid valve (hereinafter, a negative pressure solenoid valve). 63B).
  • the negative pressure solenoid valve 63B is opened and closed by a controller 7 described later.
  • the one end of the negative pressure passage 61B is constituted by a tube 620, and the other end is constituted by a hole formed in the block 600.
  • the negative pressure connector 62B penetrates through the upper end surface 201 of the housing 2 in the Z-axis direction, and a tube connected to a pump or the like that sucks air is connected to the negative pressure connector 62B from outside.
  • the common passage 61C is constituted by a hole formed in the block 600.
  • One end of the common passage 61C branches into two and is connected to the positive pressure solenoid valve 63A and the negative pressure solenoid valve 63B.
  • the other end of the common passage 61C is an air which is a through hole formed in the housing 2. It is connected to the flow passage 202A.
  • the air flow passage 202A communicates with the shaft housing 50.
  • opening the negative pressure electromagnetic valve 63B and closing the positive pressure electromagnetic valve 63A the negative pressure passage 61B and the common passage 61C communicate with each other, so that a negative pressure is generated in the common passage 61C. Then, air is sucked from the inside of the shaft housing 50 through the air flow passage 202A.
  • the positive pressure passage 61A and the common passage 61C communicate with each other, so that a positive pressure is generated in the common passage 61C. Then, air is supplied into the shaft housing 50 via the air flow passage 202A.
  • the common passage 61C is provided with a pressure sensor 64 for detecting the pressure of the air in the common passage 61C and a flow sensor 65 for detecting the flow rate of the air in the common passage 61C.
  • a part of the positive pressure passage 61A and the negative pressure passage 61B is formed by a tube, and the other part is formed by a hole formed in the block 600.
  • All the passages can be constituted by tubes, or all the passages can be constituted by holes formed in the block 600.
  • All of the common passages can be constituted by tubes, or can be constituted by using tubes in combination.
  • the material of the tube 610 and the tube 620 may be a material having flexibility such as resin, or may be a material having no flexibility such as metal.
  • an atmospheric pressure may be supplied.
  • a connector serving as an air inlet for cooling the rotary motor 20 and a connector (hereinafter, referred to as an inlet connector 91A) serving as an outlet for air from the housing 2 are provided on the upper end surface 201 of the housing 2 in the Z-axis direction.
  • this is referred to as an outlet connector 91B).
  • the inlet connector 91A and the outlet connector 91B pass through the upper end surface 201 of the housing 2 so that air can flow therethrough.
  • a tube connected to a pump or the like that discharges air is connected to the inlet connector 91A from the outside of the housing 2, and a tube that discharges air flowing out of the housing 2 is connected to the outlet connector 91B from the outside of the housing 2.
  • a metal pipe (hereinafter, referred to as a cooling pipe 92) through which air for cooling the rotary motor 20 flows is provided inside the housing 2, and one end of the cooling pipe 92 is connected to the inlet connector 91A. It is connected.
  • the cooling pipe 92 extends from the inlet connector 91 ⁇ / b> A in the Z-axis direction to a position near the lower end surface 202 of the housing 2, is curved near the lower end surface 202, and is formed so that the other end faces the rotary motor 20.
  • the cooling pipe 92 penetrates through the inside of the stator 31 so as to remove heat from the coil 31A of the linear motor 30.
  • the coil 31A is arranged around the cooling pipe 92 so as to remove more heat from the coil 31A provided on the stator 31.
  • a connector 41 including an electric wire for supplying electric power and a signal line is connected to the upper end surface 201 of the housing 2 in the Z-axis direction.
  • the housing 2 is provided with a controller 7. Electric wires and signal lines drawn into the housing 2 from the connector 41 are connected to the controller 7.
  • the controller 7 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an EPROM (Erasable Programmable ROM), which are interconnected by a bus.
  • the EPROM stores various programs, various tables, and the like.
  • the CPU loads the program stored in the EPROM into the work area of the RAM and executes the program.
  • the rotation motor 20, the direct drive motor 30, the positive pressure solenoid valve 63A, the negative pressure solenoid valve 63B, and the like are controlled. You. As a result, the CPU realizes a function that meets a predetermined purpose. Further, output signals of the pressure sensor 64, the flow sensor 65, the strain gauge 37, the rotary encoder 24, and the linear encoder 38 are input to the controller 7.
  • FIG. 3 is a cross-sectional view showing a schematic configuration of the shaft housing 50 and the tip 10A of the shaft 10.
  • the shaft housing 50 has a housing body 51, two rings 52, a filter 53, and a filter stopper 54.
  • the housing body 51 has a through hole 51A through which the shaft 10 is inserted.
  • the through-hole 51A penetrates the housing body 51 in the Z-axis direction, and an upper end of the through-hole 51A in the Z-axis direction communicates with a through-hole 2A formed in the housing 2.
  • the diameter of the through hole 51A is larger than the outer diameter of the shaft 10. Therefore, a gap is provided between the inner surface of the through hole 51A and the outer surface of the shaft 10.
  • Both ends of the through hole 51A are provided with enlarged diameter portions 51B in which the diameter of the hole is enlarged. Rings 52 are fitted into the two enlarged diameter portions 51B, respectively.
  • the ring 52 is formed in a cylindrical shape, and the inner diameter of the ring 52 is slightly larger than the outer diameter of the shaft 10. Therefore, the shaft 10 can move inside the ring 52 in the Z-axis direction. Therefore, a gap is also formed between the inner surface of the ring 52 and the outer surface of the shaft 10. Therefore, the shaft 10 can move inside the ring 52 in the Z-axis direction, and the shaft 10 can rotate around the central axis 100 inside the ring 52.
  • the gap formed between the inner surface of the ring 52 and the outer surface of the shaft 10 is smaller than the gap formed between the inner surface of the through hole 51A excluding the enlarged diameter portion 51B and the outer surface of the shaft 10.
  • the upper ring 52 in the Z-axis direction is referred to as a first ring 52A
  • the lower ring 52 in the Z-axis direction is referred to as a second ring 52B.
  • the first ring 52A and the second ring 52B are not distinguished, they are simply referred to as the ring 52.
  • the material of the ring 52 for example, metal or resin can be used.
  • an overhang portion 511 is formed which extends in both the left and right directions in the X-axis direction.
  • the overhang portion 511 has a mounting surface 511A that is a surface parallel to the lower end surface 202 of the housing 2 and that comes into contact with the lower end surface 202 when the shaft housing 50 is mounted on the lower end surface 202 of the housing 2. Have been.
  • the mounting surface 511A is a surface orthogonal to the central axis 100.
  • a part 512 of the shaft housing 50 which is above the attachment surface 511 ⁇ / b> A in the Z-axis direction, fits into the concave portion 202 ⁇ / b> B formed in the housing 2. Is formed.
  • a gap is provided between the inner surface of the through hole 51A and the outer surface of the shaft 10.
  • an inner space that is a space surrounded by the inner surface of the through hole 51A, the outer surface of the shaft 10, the lower end surface of the first ring 52A, and the upper end surface of the second ring 52B. 500 are formed.
  • a control passage 501 is formed, which communicates with an opening of an air flow passage 202A formed in the lower end surface 202 of the housing 2 and the internal space 500 to serve as an air passage.
  • the control passage 501 is a space in which the first passage 501A extending in the X-axis direction, the second passage 501B extending in the Z-axis direction, the first passage 501A and the second passage 501B are connected, and in which the filter 53 is arranged. It has a certain filter section 501C. One end of the first passage 501A is connected to the internal space 500, and the other end is connected to the filter unit 501C. One end of the second passage 501B is open to the mounting surface 511A, and is positioned so as to be connected to the opening of the air flow passage 202A.
  • the filter unit 501C is provided with a filter 53 formed in a cylindrical shape.
  • the filter portion 501C is formed so as to be a cylindrical space extending in the X-axis direction so that the center axis of the first passage 501A coincides with the center axis.
  • the inner diameter of the filter portion 501C is substantially equal to the outer diameter of the filter 53.
  • the filter 53 is inserted into the filter unit 501C in the X-axis direction. After the filter 53 is inserted into the filter unit 501C, the filter stopper 54 closes the end of the filter unit 501C that has become the insertion port of the filter 53.
  • the other end of the second passage 501B is connected to the filter section 501C from the outer peripheral surface side of the filter 53.
  • the other end of the first passage 501A communicates with the center of the filter 53. Therefore, the air flowing between the first passage 501A and the second passage 501B passes through the filter 53. Therefore, for example, even when foreign matter is sucked into the internal space 500 together with air when a negative pressure is generated at the distal end portion 10A, the foreign matter is collected by the filter 53.
  • a groove 501D is formed at one end of the second passage 501B so as to hold the sealant.
  • two bolt holes 51G through which the bolts are inserted when the shaft housing 50 is fixed to the housing 2 using bolts are formed.
  • the bolt hole 51G penetrates the projecting portion 511 in the Z-axis direction and opens on the mounting surface 511A.
  • a hollow portion 11 is formed on the tip 10A side of the shaft 10 so that the shaft 10 becomes hollow.
  • One end of the hollow part 11 is open at the tip part 10A.
  • a communication hole 12 that connects the internal space 500 and the hollow portion 11 in the X-axis direction is formed.
  • the communication hole 12 is formed such that the internal space 500 and the hollow portion 11 communicate with each other over the entire range of the stroke when the shaft 10 is moved in the Z-axis direction by the linear motor 30. Therefore, the distal end portion 10A of the shaft 10 and the air control mechanism 60 communicate with each other through the hollow portion 11, the communication hole 12, the internal space 500, the control passage 501, and the air flow passage 202A.
  • the communication hole 12 may be formed in the Y-axis direction in addition to the X-axis direction.
  • the communication hole 12 is always in the internal space regardless of the position of the shaft 10 in the Z-axis direction. 500 and the hollow portion 11 are communicated. Further, when the rotation motor 20 is driven to rotate the shaft 10 around the central axis 100, the communication hole 12 is always in contact with the internal space 500 regardless of the rotation angle of the shaft 10 around the central axis 100. The hollow portion 11 is communicated. Therefore, regardless of the state of the shaft 10, the communication between the hollow portion 11 and the internal space 500 is maintained, so that the hollow portion 11 always communicates with the air control mechanism 60.
  • this gap is smaller than the gap forming the internal space 500 (that is, the gap formed between the inner surface of the through hole 51A and the outer surface of the shaft 10). Therefore, by closing the positive pressure solenoid valve 63A and opening the negative pressure solenoid valve 63B in the air control mechanism 60, even if air is sucked from the interior space 500, the air gap between the inner surface of the ring 52 and the outer surface of the shaft 10 is maintained. The flow rate of the air flowing through the gap can be suppressed. Thereby, a negative pressure capable of picking up the work W can be generated at the distal end portion 10A of the shaft 10.
  • the pick and place of the work W using the actuator 1 will be described.
  • the pick and place is performed by the controller 7 executing a predetermined program.
  • the positive pressure solenoid valve 63A and the negative pressure solenoid valve 63B are both closed until the shaft 10 comes into contact with the work W.
  • the pressure at the distal end 10A of the shaft 10 becomes the atmospheric pressure.
  • the shaft 10 is moved downward in the Z-axis direction by the linear motor 30.
  • the linear motor 30 is stopped.
  • the shaft 10 in a state where the work W is attracted to the distal end portion 10A is moved downward by the linear motor 30 in the Z-axis direction.
  • the movement of the shaft 10 is stopped by stopping the linear motor 30.
  • closing the negative pressure electromagnetic valve 63B and opening the positive pressure electromagnetic valve 63A a positive pressure is generated at the tip 10A of the shaft 10.
  • the distal end portion 10A of the shaft 10 is separated from the workpiece W by moving the shaft 10 upward in the Z-axis direction by the linear motor 30.
  • the strain gauge 37 when the work W is picked up, the fact that the tip 10A of the shaft 10 has come into contact with the work W is detected using the strain gauge 37.
  • this method will be described.
  • the work W is grounded when the work W is placed.
  • the tip 10A of the shaft 10 contacts the work W and the tip 10A pushes the work W, a load is generated between the shaft 10 and the work W. That is, the shaft 10 receives a force from the work W due to a reaction when the shaft 10 applies a force to the work W.
  • the force that the shaft 10 receives from the work W acts in a direction that generates strain on the connecting arm 36. That is, at this time, the connection arm 36 is distorted. This strain is detected by the strain gauge 37.
  • the strain detected by the strain gauge 37 has a correlation with the force that the shaft 10 receives from the workpiece W. For this reason, based on the detection value of the strain gauge 37, the force that the shaft 10 receives from the work W, that is, the load generated between the shaft 10 and the work W can be detected.
  • the relationship between the detected value of the strain gauge and the load can be obtained in advance by experiment, simulation, or the like.
  • the tip 10A of the shaft 10 May be determined, or when the detected load is equal to or more than a predetermined load in consideration of the influence of an error or the like, it may be determined that the distal end portion 10A of the shaft 10 has contacted the workpiece W.
  • the predetermined load is a threshold value at which it is determined that the shaft 10 has contacted the workpiece W.
  • the predetermined load may be set as a load that can more reliably pick up the work W while suppressing damage to the work W. Further, the predetermined load can be changed according to the type of the work W.
  • the change in the resistance value due to the strain of the strain gauge 37 is extremely small, it is extracted as a voltage change using a Wheatstone bridge circuit.
  • the output of the bridge circuit related to the first strain gauge 37A and the output of the bridge circuit related to the second strain gauge 37B are connected in parallel. As described above, by connecting the outputs of both bridge circuits in parallel, a voltage change that eliminates the influence of temperature as described below is obtained.
  • the loads detected by the first strain gauge 37A and the second strain gauge 37B are substantially the same.
  • the temperature of the linear motor 30 is higher than the temperature of the rotary motor 20.
  • the amount of expansion of the translation table 33 in the Z-axis direction is larger than the amount of expansion of the rotary motor 20 in the Z-axis direction.
  • the first arm 36A and the second arm 36B are not parallel, and the distance between the first arm 36A and the second arm 36B is larger on the side of the linear motor 30 than on the side of the rotary motor 20.
  • the first strain gauge 37A contracts and the second strain gauge 37B expands.
  • the output of the first strain gauge 37A apparently indicates the occurrence of a load
  • the output of the second strain gauge 37B apparently indicates the occurrence of a negative load.
  • the force generated by the difference between the amount of expansion of the translation table 33 in the Z-axis direction and the amount of expansion of the rotary motor 20 in the Z-axis direction is equally applied to the first arm 36A and the second arm 36B in the opposite direction.
  • the output of the first strain gauge 37A and the output of the second strain gauge 37B have the same absolute value and different signs. Therefore, by connecting the outputs of both strain gauges in parallel, the outputs due to the influence of temperature can be canceled each other, so that it is not necessary to separately perform correction according to temperature. Therefore, it is possible to easily and accurately detect the load. In this way, by connecting the outputs of both bridge circuits in parallel, it is possible to obtain a voltage change that eliminates the influence of temperature, and this voltage change corresponds to the load generated between the shaft 10 and the work W. Value.
  • two strain gauges 37 are provided, but only one of the first strain gauge 37A and the second strain gauge 37B may be provided instead.
  • the detected value of the strain gauge is corrected according to the temperature using a known technique. Even when one strain gauge 37 is provided, the output of the strain gauge 37 is a value corresponding to the load generated between the shaft 10 and the workpiece W. It is possible to detect a load generated between the workpiece 10 and the work W.
  • the strain gauge 37 on the connecting arm 36, it is possible to detect that the shaft 10 is in contact with the workpiece W.
  • a spring or a highly flexible member for example, rubber
  • the force applied to the work W without lowering the speed of the shaft 10 can be adjusted more precisely.
  • the work W can be picked up more reliably. For example, when picking up the work W, the work W can be more reliably picked up by generating a negative pressure in the hollow portion 11 in a state where the work W is pressed against the distal end portion 10A of the shaft 10. When the work W is sucked, the work W can be prevented from violently colliding with the shaft 10 and being damaged. On the other hand, if the load pressing the work W is too large, the work W may be damaged. Therefore, by applying an appropriate load to the work W while detecting the load applied to the work W, it is possible to more reliably pick up the work W while suppressing damage to the work W.
  • the entire shaft 10 may have a hollow structure and a rotary joint may be provided at the base end portion of the shaft 10. Positive pressure and negative pressure can be supplied through this rotary joint.
  • a larger torque is required to move the shaft 10 in the Z-axis direction or rotate around the central axis 100, so that it is necessary to employ a motor having a larger torque.
  • a negative pressure can be generated in the hollow portion 11 of the shaft 10 without using a rotary joint. Then, it is not necessary to select a rotary motor having a large torque in order to move the rotary joint. There is no need to increase the frequency of maintenance.
  • the shaft 10 When the positive pressure and the negative pressure are supplied via the rotary joint, the shaft 10 receives a force from a tube or the like connected to the rotary joint, and this force is included in the output of the strain gauge 37. Therefore, it may be difficult to accurately detect the load applied to the work W.
  • the shaft housing 50 As in the actuator 1 according to the present embodiment, it is not necessary to use a rotary joint, so that the accuracy of the load detected by the strain gauge 37 can be reduced. Can be more enhanced.
  • the actuator 1 is formed so that a plurality of actuators 1 can be stacked in the Y-axis direction.
  • the plurality of actuators 1 can be stacked even when adjacent actuators 1 are rotated by 180 degrees around the Z axis. Since the shaft 10 is provided at the center in the X-axis direction and the center in the Y-axis direction of the housing 2, the position of the shaft 10 does not change even if the actuator 1 is rotated 180 degrees around the Z axis.
  • the connecting arm 36 is provided with the strain gauge 37.
  • any member that generates a strain in accordance with the load may be used.
  • Another member may be provided with the strain gauge 37.
  • FIGS. 4 and 5 are diagrams showing a schematic configuration in the case where strain gauges 37 are provided on two bearings 25 supporting the output shaft 21 of the rotary motor 20, respectively.
  • FIG. 4 is a diagram around the bearing 25A provided on the upper side in the Z-axis direction
  • FIG. 5 is a diagram around the bearing 25B provided on the lower side in the Z-axis direction.
  • the bearings 25 are provided on the output shaft 21 above (see FIG. 4) and below (see FIG. 5) the rotor 23 in the Z-axis direction, respectively.
  • the bearing 25 ⁇ / b> A has an inner peripheral surface fitted on the outer peripheral surface of the output shaft 21, and an outer peripheral surface fitted on an inner peripheral surface of a fixing portion 220 ⁇ / b> A formed on the stator 22.
  • the fixing portion 220A has an upper protruding portion 221A protruding toward the center shaft 100 side so as to be in contact with an upper side of the bearing 25A in the Z-axis direction.
  • a first strain gauge 37A is provided on an upper surface of the upper protrusion 221A in the Z-axis direction.
  • the bearing 25 ⁇ / b> B has an inner peripheral surface fitted on the outer peripheral surface of the output shaft 21, and an outer peripheral surface fitted on an inner peripheral surface of a fixing portion 220 ⁇ / b> B formed on the stator 22.
  • the fixing portion 220B has a lower protruding portion 221B protruding toward the central shaft 100 so as to contact the upper side of the bearing 25B in the Z-axis direction.
  • a second strain gauge 37B is provided on the upper surface of the lower protrusion 221B in the Z-axis direction.
  • the first strain gauge 37A and the second strain gauge 37B are provided on surfaces parallel to each other in the same direction and orthogonal to the central axis 100 of the shaft 10.
  • the load generated between the shaft 10 and the work W causes distortion in the upper protrusion 221A and the lower protrusion 221B. Since this strain is correlated with the load generated between the shaft 10 and the work W, the strain gauge 37 detects the strain to detect the load generated between the shaft 10 and the work W. be able to.
  • the first strain gauge 37A and the second strain gauge 37B detect strains in opposite directions under the influence of temperature.
  • the upper protruding portion 221A and the lower protruding portion 221B are turned in opposite directions. The same amount of force is applied.
  • the output of the first strain gauge 37A and the output of the second strain gauge 37B have the same absolute value and different positive and negative. Therefore, by connecting the outputs of both strain gauges in parallel, the outputs due to the influence of temperature can be canceled each other, so that it is not necessary to separately perform correction according to temperature. Therefore, the load applied to the shaft 10 and the work W can be easily and accurately detected.
  • connection arm 36 is provided with the strain gauge 37.
  • connection arm 35 may be provided with the strain gauge 37. That is, in each of the two connecting arms 35, a strain gauge 37 can be provided on a surface facing upward in the Z-axis direction. In each of the two connecting arms 35, a strain gauge 37 may be provided on a surface facing downward in the Z-axis direction. A strain corresponding to the magnitude of the load generated between the shaft 10 and the work W is also generated on the surface of the connection arm 36 facing upward or downward in the Z-axis direction. Therefore, the load can be detected by detecting the strain.
  • the two connecting arms 35 are also displaced in the Z-axis direction, and their respective central axes are parallel to each other, and their respective central axes are orthogonal to the central axis 100 of the shaft 10. Therefore, as described in the first embodiment, even when a strain occurs in the connection arm 35 due to thermal expansion, the influence of the strain due to thermal expansion can be reduced by connecting the outputs of the two strain gauges in parallel. Can be countered. Therefore, the load applied to the shaft 10 and the work W can be easily and accurately detected.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
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Abstract

The present invention detects a load applied to a shaft and a work piece. A load detector for detecting a force applied to a shaft in an actuator provided with the shaft, a support part for rotatably supporting the shaft, a linear motor for causing the shaft to move in the direction of a center axis, and a connecting member which is at least a portion of a member for connecting the support part and a movable element of the linear motor, wherein the load detector comprises a strain gauge for detecting strain in the connecting member, the strain gauge being provided to the connecting member.

Description

アクチュエータの荷重検出器Actuator load detector
　本発明は、アクチュエータの荷重検出器に関する。 The present invention relates to a load detector for an actuator.
　中空のシャフトをワークに押し付けた状態でシャフト内を負圧にすることで、ワークをシャフトに吸い付けて、ワークをピックアップすることができる。ここで、ワークをシャフトに吸い付けるときに、ワークとシャフトとの間に隙間があると、ワークがシャフトに勢いよく衝突してワークが破損する虞や、ワークを吸い付けることができない虞がある。一方、ワークを押し付ける荷重が大きすぎると、ワークが破損する虞がある。したがって、シャフトをワークに適切な荷重で押し付けることが望まれている。また、シャフトがワークに接する際にシャフトの速度が高いと、シャフトがワークに衝突することによりワークが破損する虞があるため、この衝撃を緩和することが望まれている。従来では、シャフト本体の先端にばね等の緩衝部材を介して吸着部材を設けている（例えば、特許文献１参照。）。すなわち、吸着部材がワークに接した際に、ばねが縮むことで衝撃を緩和している。その後、さらにシャフトがワークに向かって移動したときには、ばね定数に応じた荷重でワークを押し付けている。 負 By making the inside of the shaft a negative pressure while pressing the hollow shaft against the work, the work can be sucked to the shaft and the work can be picked up. Here, if there is a gap between the work and the shaft when the work is sucked to the shaft, the work may vigorously collide with the shaft and be damaged, or the work may not be sucked. . On the other hand, if the load pressing the work is too large, the work may be damaged. Therefore, it is desired to press the shaft against the work with an appropriate load. In addition, if the speed of the shaft is high when the shaft contacts the work, the work may be damaged by the collision of the shaft with the work. Therefore, it is desired to reduce the impact. Conventionally, a suction member is provided at the tip of a shaft main body via a buffer member such as a spring (for example, see Patent Document 1). That is, when the suction member comes into contact with the work, the spring is contracted to reduce the impact. Thereafter, when the shaft further moves toward the work, the work is pressed with a load corresponding to the spring constant.
特開２００９－１６４３４７号公報JP 2009-164347 A
　ワークによって適切な荷重が異なる場合があるが、上記のような緩衝部材を設ける場合には、ワークに加わる荷重はばね定数によって決まるため、ワークに加わる荷重をワークに応じて変更することは困難であった。このような構成でワークに加わる荷重を調整する場合には、例えば緩衝部材を交換する必要があった。また、上記のような緩衝部材を設ける場合には、ワークに加わる荷重にばらつきが生じやすいため、高い精度で荷重を調整する必要のあるワークに用いることは困難であった。ここで、シャフト及びワークに加わる荷重を検出することができれば、検出した荷重に応じてシャフトを制御することができる。 The appropriate load may differ depending on the work.However, when the cushioning member as described above is provided, the load applied to the work is determined by the spring constant, so it is difficult to change the load applied to the work according to the work. there were. When adjusting the load applied to the work in such a configuration, for example, it is necessary to replace the buffer member. Further, in the case where the buffer member as described above is provided, the load applied to the work tends to vary, so that it is difficult to use the work for a work that requires a high-precision load adjustment. Here, if the load applied to the shaft and the work can be detected, the shaft can be controlled according to the detected load.
　本発明は、上記したような種々の実情を鑑みてなされたものであり、その目的は、シャフト及びワークに加わる荷重を検出することにある。 The present invention has been made in view of the various circumstances as described above, and an object of the present invention is to detect a load applied to a shaft and a work.
　本発明の態様の一つは、シャフトと、前記シャフトを回転可能に支持する支持部と、固定子及び可動子を有する直動モータであって、前記直動モータの前記固定子に対して前記可動子が前記シャフトの中心軸と平行に移動することにより、前記支持部及び前記シャフトを前記シャフトの前記中心軸の方向に移動させる直動モータと、前記直動モータの前記可動子と前記支持部とを接続する部材の少なくとも一部である接続部材と、を備えるアクチュエータにおいて前記シャフトにかかる力を検出する荷重検出器であって、前記接続部材に設けられ前記接続部材のひずみを検出するひずみゲージを備える、荷重検出器である。 One aspect of the present invention is a linear motor having a shaft, a support portion rotatably supporting the shaft, and a stator and a mover, wherein the linear motor has a position relative to the stator. A linear motor that moves the support section and the shaft in the direction of the central axis of the shaft by moving the mover in parallel with the central axis of the shaft; A connection member that is at least a part of a member that connects the first and second portions, and a load detector that detects a force applied to the shaft in an actuator including: a strainer that is provided on the connection member and detects a strain of the connection member. It is a load detector provided with a gauge.
　本発明によれば、シャフト及びワークに加わる荷重を検出することができる。 According to the present invention, the load applied to the shaft and the work can be detected.
実施形態に係るアクチュエータの外観図である。FIG. 2 is an external view of an actuator according to the embodiment. 実施形態に係るアクチュエータの内部構造を示した概略構成図である。FIG. 1 is a schematic configuration diagram illustrating an internal structure of an actuator according to an embodiment. 実施形態に係るシャフトハウジングとシャフトの先端部との概略構成を示した断面図である。It is sectional drawing which showed schematic structure of the shaft housing which concerns on embodiment, and the front-end | tip part of a shaft. 実施形態に係る回転モータの出力軸を支持する軸受にひずみゲージを設けた場合の概略構成を示す図である。It is a figure showing the schematic structure at the time of providing a strain gauge in the bearing which supports the output shaft of the rotation motor concerning an embodiment. 実施形態に係る回転モータの出力軸を支持する軸受にひずみゲージを設けた場合の概略構成を示す図である。It is a figure showing the schematic structure at the time of providing a strain gauge in the bearing which supports the output shaft of the rotation motor concerning an embodiment.
　本発明の態様の一つである荷重検出器では、直動モータによって、支持部及びシャフトが可動子の移動方向に移動する。直動モータの可動子の移動方向は、シャフトの中心軸方向と平行であるため、直動モータの駆動により、シャフトが中心軸方向に移動する。直動モータは例えばリニアモータである。また、支持部は例えば、シャフトを回転させる回転モータや、該回転モータの固定子と該回転モータの出力軸との間に設けられるベアリングである。直動モータの可動子は、支持部に接続部材を介して接続されている。なお、接続部材は複数存在していてもよい。また、直動モータの可動子と接続部材とが一体になっていてもよく、また、支持部と接続部材とが一体になっていてもよい。支持部は、直動モータの駆動に関わらずシャフトを回転可能に支持している。したがって、直動モータによってシャフトを中心軸方向に移動することと、シャフトを中心軸回りに回転することと、を個別に行うことができる。ワークをピックアップするときには、シャフトがワークに接するまで直動モータがシャフトを移動させる。 In the load detector which is one aspect of the present invention, the support and the shaft are moved in the moving direction of the mover by the linear motor. Since the moving direction of the mover of the linear motor is parallel to the central axis direction of the shaft, the shaft moves in the central axis direction by driving the linear motor. The linear motor is, for example, a linear motor. The support portion is, for example, a rotation motor for rotating a shaft, or a bearing provided between a stator of the rotation motor and an output shaft of the rotation motor. The mover of the linear motion motor is connected to the support via a connecting member. Note that a plurality of connection members may exist. In addition, the mover of the linear motion motor and the connection member may be integrated, or the support portion and the connection member may be integrated. The support portion rotatably supports the shaft regardless of the driving of the linear motor. Therefore, it is possible to individually move the shaft in the central axis direction and rotate the shaft around the central axis by the linear motion motor. When picking up the work, the linear motion motor moves the shaft until the shaft contacts the work.
　直動モータの駆動によりシャフトがワークに接すると、シャフトとワークとの間に荷重が発生する。このため、接続部材の一端側（直動モータ側）には、シャフトをワークに向かわせる方向の力が作用し、接続部材の他端側（支持部側）には、シャフトをワークから離す方向に向かわせる力が作用するため、接続部材にひずみが生じる。このひずみは、シャフトとワークとの間に発生する荷重と相関関係がある。したがって、このひずみをひずみゲージで検出することにより、シャフト及びワークに加わる荷重を検出することができる。 す る と When the shaft comes into contact with the work by driving the linear motor, a load is generated between the shaft and the work. For this reason, a force in a direction for moving the shaft toward the work is applied to one end side (the linear motor side) of the connection member, and a direction in which the shaft is separated from the work is applied to the other end side (the support portion side) of the connection member. As a result, the connecting member is distorted. This strain has a correlation with the load generated between the shaft and the work. Therefore, the load applied to the shaft and the work can be detected by detecting the strain with the strain gauge.
　また、前記接続部材は、前記シャフトの前記中心軸の方向にずらして設けられる第一部材及び第二部材を有し、前記ひずみゲージは、前記第一部材及び前記第二部材に夫々に設けられる同じ方向を向く互いに平行な面であって前記シャフトの前記中心軸と直交する面に夫々設けられていてもよい。 In addition, the connection member has a first member and a second member that are provided to be shifted in a direction of the central axis of the shaft, and the strain gauge is provided in each of the first member and the second member. The shafts may be provided on surfaces parallel to each other in the same direction and orthogonal to the central axis of the shaft.
　ここで、直動モータが作動すると熱を発生する。また、アクチュエータに備わる他の装置が熱を発生することもある。これらの熱により、直動モータ、支持部、及び接続部材が熱膨張することがある。この場合には、ワークからシャフトに荷重が加わっていなくとも、第一部材及び第二部材にひずみが生じ得る。例えば、第一部材及び第二部材の一端側が接続されている部材と、他端側が接続されている部材とで温度差があると、膨張量に差が生じる場合がある。なお、以下では例示的に、第一部材及び第二部材の一端側が接続されている部材を熱による膨張量が大きな部材（高膨張部材）として説明し、他端側が接続されている部材を熱による膨張量が小さな部材（低膨張部材）として説明する。このように第一部材及び第二部材が高膨張部材及び低膨張部材に接続されている場合には、第一部材と第二部材との距離が低膨張部材側よりも高膨張部材側で大きくなり得る。そして、高膨張部材側では、第一部材と第二部材とを引き離す方向に、第一部材と第二部材とに夫々逆方向の力がかかる。そのため、第一部材及び第二部材に夫々に設けられる同じ方向を向く互いに平行な面であってシャフトの中心軸と直交する面のうちの、一方の面には縮む方向のひずみが発生し、他方の面には伸びる方向のひずみが発生する。そのため、第一部材に設けられているひずみゲージと、第二部材に設けられているひずみゲージとでは、一方が縮む方向のひずみに対応する出力をし、他方が伸びる方向のひずみに対応する出力をする。このときに、第一部材と第二部材とには、夫々に逆方向の同じ大きさの力がかかっているため、一方のひずみゲージの出力と、他方のひずみゲージの出力とは、正負は異なるがその絶対量は略同じになる。そのため、両ひずみゲージの出力を並列に接続することにより、熱膨張の影響を互いに打ち消し合うため、別途温度に応じた補正を行う必要がなくなる。すなわち、簡易且つ高精度にシャフト及びワークに加わる荷重のみを検出することができる。 熱 Here, when the linear motor operates, heat is generated. Also, other devices provided in the actuator may generate heat. Due to such heat, the linear motion motor, the support portion, and the connection member may thermally expand. In this case, even if no load is applied to the shaft from the workpiece, distortion may occur in the first member and the second member. For example, if there is a temperature difference between a member to which one end of the first member and the second member is connected and a member to which the other end is connected, a difference may occur in the amount of expansion. In the following, a member to which one end of the first member and the second member is connected is described as a member having a large amount of expansion due to heat (a high expansion member), and a member to which the other end is connected is heat. The description will be made assuming that a member (low-expansion member) having a small amount of expansion due to is used. When the first member and the second member are thus connected to the high expansion member and the low expansion member, the distance between the first member and the second member is larger on the high expansion member side than on the low expansion member side. Can be. Then, on the high expansion member side, forces in opposite directions are applied to the first member and the second member, respectively, in a direction of separating the first member and the second member. For this reason, a strain in a contracting direction is generated on one of the surfaces parallel to each other in the same direction provided on the first member and the second member and orthogonal to the center axis of the shaft, On the other surface, a strain occurs in the direction of extension. Therefore, one of the strain gauge provided on the first member and the strain gauge provided on the second member has an output corresponding to the strain in the contracting direction and the other has an output corresponding to the strain in the extending direction. do. At this time, since the same force in the opposite direction is applied to the first member and the second member, respectively, the output of one strain gauge and the output of the other strain gauge are positive or negative. Although different, the absolute amount is almost the same. Therefore, by connecting the outputs of the two strain gauges in parallel, the effects of thermal expansion are canceled each other, so that it is not necessary to separately perform correction according to the temperature. That is, it is possible to simply and accurately detect only the load applied to the shaft and the work.
　例えば、前記第一部材に設けられるひずみゲージと、前記第二部材に設けられるひずみゲージとは、夫々が異なるホイートストンブリッジ回路に組み込まれ、両ホイートストンブリッジ回路の出力が並列に接続されていてもよい。このように回路を形成することにより、両ひずみゲージの出力における熱の影響の分を打ち消し合うため、最終的な出力は、シャフトとワークとの間に発生する荷重に応じた出力となる。 For example, the strain gauge provided on the first member and the strain gauge provided on the second member may be incorporated in different Wheatstone bridge circuits, respectively, and outputs of both Wheatstone bridge circuits may be connected in parallel. . By forming the circuit in this manner, the effect of heat on the outputs of both strain gauges is canceled out, and the final output is an output corresponding to the load generated between the shaft and the work.
　なお、前記支持部が、固定子及び回転子を有する回転モータであって、前記回転モータの前記固定子に対して、前記シャフトに接続される前記回転子が回転することにより、前記シャフトを前記シャフトの前記中心軸の回りに回転させる回転モータであり、前記第一部材及び前記第二部材は、前記直動モータの前記可動子と前記回転モータの前記固定子とを接続する２つのアームであって、前記２つのアームの夫々の中心軸が前記シャフトの前記中心軸の方向と直交し、且つ、前記２つのアームの前記中心軸が互いに平行になる２つのアームであってもよい。このようなアームによれば、直動モータと回転モータとの間にある程度の距離が生じるため、夫々の熱の影響や磁界の影響を受け難くすることができる。なお、支持部が、回転モータの固定子と回転モータの出力軸との間に設けられるベアリングであってもよく、その場合、接続部材が、そのベアリングに接する部材（例えば回転モータの固定子）であってもよい。 Note that the support portion is a rotary motor having a stator and a rotor, and the rotor connected to the shaft rotates with respect to the stator of the rotary motor, thereby rotating the shaft. A rotation motor that rotates around the central axis of the shaft, wherein the first member and the second member are two arms that connect the mover of the linear motion motor and the stator of the rotation motor. There may be two arms in which the respective central axes of the two arms are orthogonal to the direction of the central axis of the shaft, and the central axes of the two arms are parallel to each other. According to such an arm, since a certain distance is generated between the linear motion motor and the rotary motor, it is possible to make the arm less susceptible to the effects of heat and magnetic fields. The supporting portion may be a bearing provided between the stator of the rotary motor and the output shaft of the rotary motor. In this case, the connecting member is a member (for example, a stator of the rotary motor) in contact with the bearing. It may be.
　以下に図面を参照して、本発明を実施するための形態を説明する。ただし、この実施形態に記載されている構成部品の寸法、材質、形状、その相対配置などは、特に記載がない限りは、この発明の範囲をそれらのみに限定する趣旨のものではない。 Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to them unless otherwise specified.
＜第１実施形態＞
　図１は、本実施形態に係るアクチュエータ１の外観図である。アクチュエータ１は外形が略直方体のハウジング２を有しており、ハウジング２には、蓋２００が取り付けられている。図２は、本実施形態に係るアクチュエータ１の内部構造を示した概略構成図である。ハウジング２の内部に、シャフト１０の一部を収容している。このシャフト１０の先端部１０Ａ側は、中空となるよう形成されている。シャフト１０及びハウジング２の材料には、例えば金属（例えばアルミニウム）を用いることができるが、樹脂等を用いることもできる。なお、以下の説明においては、ＸＹＺ直交座標系を設定し、このＸＹＺ直交座標系を参照しつつ各部材の位置について説明する。ハウジング２の最も大きな面の長辺方向であってシャフト１０の中心軸１００の方向をＺ軸方向とし、ハウジング２の最も大きな面の短辺方向をＸ軸方向とし、ハウジング２の最も大きな面と直交する方向をＹ軸方向とする。Ｚ軸方向は鉛直方向でもある。なお、以下では、図２におけるＺ軸方向の上側をアクチュエータ１の上側とし、図２におけるＺ軸方向の下側をアクチュエータ１の下側とする。また、図２におけるＸ軸方向の右側をアクチュエータ１の右側とし、図２におけるＸ軸方向の左側をアクチュエータ１の左側とする。また、図２におけるＹ軸方向の手前側をアクチュエータ１の手前側とし、図２におけるＹ軸方向の奥側をアクチュエータ１の奥側とする。ハウジング２は、Ｚ軸方向の寸法がＸ軸方向の寸法よりも長く、Ｘ軸方向の寸法がＹ軸方向の寸法よりも長い。ハウジング２は、Ｙ軸方向と直交する一つの面（図２における手前側の面）に相当する箇所が開口しており、この開口を蓋２００によって閉塞している。蓋２００は、例えばネジによってハウジング２に固定される。 <First embodiment>
FIG. 1 is an external view of an actuator 1 according to the present embodiment. The actuator 1 has a housing 2 having a substantially rectangular parallelepiped outer shape, and a lid 200 is attached to the housing 2. FIG. 2 is a schematic configuration diagram illustrating an internal structure of the actuator 1 according to the present embodiment. A part of the shaft 10 is housed inside the housing 2. The tip 10A side of the shaft 10 is formed to be hollow. As a material of the shaft 10 and the housing 2, for example, a metal (for example, aluminum) can be used, but a resin or the like can also be used. In the following description, an XYZ rectangular coordinate system is set, and the position of each member will be described with reference to the XYZ rectangular coordinate system. The long side direction of the largest surface of the housing 2 and the direction of the central axis 100 of the shaft 10 are defined as the Z-axis direction, the short side direction of the largest surface of the housing 2 is defined as the X-axis direction. The direction perpendicular to the direction is defined as a Y-axis direction. The Z-axis direction is also the vertical direction. In the description below, the upper side in the Z-axis direction in FIG. 2 is referred to as the upper side of the actuator 1, and the lower side in the Z-axis direction in FIG. The right side in the X-axis direction in FIG. 2 is the right side of the actuator 1, and the left side in the X-axis direction in FIG. The near side in the Y-axis direction in FIG. 2 is the near side of the actuator 1, and the far side in the Y-axis direction in FIG. The housing 2 has a dimension in the Z-axis direction longer than a dimension in the X-axis direction, and a dimension in the X-axis direction is longer than a dimension in the Y-axis direction. The housing 2 has an opening at a position corresponding to one surface (a surface on the near side in FIG. 2) orthogonal to the Y-axis direction, and this opening is closed by a lid 200. The lid 200 is fixed to the housing 2 by, for example, screws.
　ハウジング２内には、シャフト１０をその中心軸１００回りに回転させる回転モータ２０と、シャフト１０をその中心軸１００に沿った方向（すなわち、Ｚ軸方向）にハウジング２に対して相対的に直動させる直動モータ３０と、エア制御機構６０とが収容されている。また、ハウジング２のＺ軸方向の下端面２０２には、シャフト１０が挿通されたシャフトハウジング５０が取り付けられている。ハウジング２には、下端面２０２からハウジング２の内部に向かって凹むように凹部２０２Ｂが形成されており、この凹部２０２Ｂにシャフトハウジング５０の一部が挿入される。この凹部２０２ＢのＺ軸方向の上端部には、Ｚ軸方向に貫通孔２Ａが形成されており、この貫通孔２Ａ及びシャフトハウジング５０をシャフト１０が挿通される。シャフト１０のＺ軸方向の下側の先端部１０Ａは、シャフトハウジング５０から外部へ突出している。シャフト１０は、ハウジング２のＸ軸方向の中心且つＹ軸方向の中心に設けられている。つまり、ハウジング２における、Ｘ軸方向の中心およびＹ軸方向の中心を通ってＺ軸方向に延びる中心軸と、シャフト１０の中心軸１００とが重なるように、シャフト１０が設けられている。シャフト１０は、直動モータ３０によってＺ軸方向に直動すると共に、回転モータ２０によって中心軸１００の回りを回転する。 Inside the housing 2, a rotation motor 20 for rotating the shaft 10 around its central axis 100, and the shaft 10 in a direction along the central axis 100 (that is, the Z-axis direction) relative to the housing 2. The linear motion motor 30 to be moved and the air control mechanism 60 are accommodated. A shaft housing 50 into which the shaft 10 is inserted is attached to a lower end surface 202 of the housing 2 in the Z-axis direction. The housing 2 has a recess 202B formed so as to be recessed from the lower end surface 202 toward the inside of the housing 2, and a part of the shaft housing 50 is inserted into the recess 202B. A through-hole 2A is formed at the upper end of the concave portion 202B in the Z-axis direction in the Z-axis direction, and the shaft 10 is inserted through the through-hole 2A and the shaft housing 50. A lower end portion 10A of the shaft 10 on the lower side in the Z-axis direction projects from the shaft housing 50 to the outside. The shaft 10 is provided at the center of the housing 2 in the X-axis direction and the center of the housing 2 in the Y-axis direction. That is, the shaft 10 is provided such that the center axis of the housing 2 extending in the Z-axis direction through the center in the X-axis direction and the center in the Y-axis direction and the center axis 100 of the shaft 10 overlap. The shaft 10 is linearly moved in the Z-axis direction by a linear motor 30 and is rotated around a central axis 100 by a rotary motor 20.
　シャフト１０の先端部１０Ａと逆側の端部（Ｚ軸方向の上側の端部）である基端部１０Ｂ側は、ハウジング２内に収容されており、回転モータ２０の出力軸２１に接続されている。この回転モータ２０は、シャフト１０を回転可能に支持している。回転モータ２０の出力軸２１の中心軸は、シャフト１０の中心軸１００と一致する。回転モータ２０は、出力軸２１の他に、固定子２２と、固定子２２の内部で回転する回転子２３と、出力軸２１の回転角度を検出するロータリエンコーダ２４とを有する。回転子２３が固定子２２に対して回転することにより、出力軸２１及びシャフト１０も固定子２２に対して連動して回転する。 A base end 10B side of the shaft 10 opposite to the front end 10A (the upper end in the Z-axis direction) is housed in the housing 2 and connected to the output shaft 21 of the rotary motor 20. ing. The rotary motor 20 rotatably supports the shaft 10. The center axis of the output shaft 21 of the rotary motor 20 matches the center axis 100 of the shaft 10. The rotary motor 20 includes, in addition to the output shaft 21, a stator 22, a rotor 23 that rotates inside the stator 22, and a rotary encoder 24 that detects a rotation angle of the output shaft 21. When the rotor 23 rotates with respect to the stator 22, the output shaft 21 and the shaft 10 also rotate in conjunction with the stator 22.
　直動モータ３０は、ハウジング２に固定された固定子３１、固定子３１に対して相対的にＺ軸方向に移動する可動子３２を有する。直動モータ３０は、例えばリニアモータである。固定子３１には複数のコイル３１Ａが設けられ、可動子３２には複数の永久磁石３２Ａが設けられている。コイル３１Ａは、Ｚ軸方向に所定ピッチで配置され、且つ、Ｕ，Ｖ，Ｗ相の３つのコイル３１Ａを一組として複数設けられている。本実施形態では、これらＵ，Ｖ，Ｗ相のコイル３１Ａに三相電機子電流を流すことによって直動的に移動する移動磁界を発生させ、固定子３１に対して可動子３２を直動的に移動させる。直動モータ３０には固定子３１に対する可動子３２の相対位置を検出するリニアエンコーダ３８が設けられている。なお、上記構成に代えて、固定子３１に永久磁石を設け、可動子３２に複数のコイルを設けることもできる。 The linear motor 30 has a stator 31 fixed to the housing 2 and a mover 32 that moves in the Z-axis direction relative to the stator 31. The linear motor 30 is, for example, a linear motor. The stator 31 is provided with a plurality of coils 31A, and the mover 32 is provided with a plurality of permanent magnets 32A. The coils 31A are arranged at a predetermined pitch in the Z-axis direction, and a plurality of coils 31A of the U, V, and W phases are provided as a set. In the present embodiment, a moving magnetic field that moves linearly is generated by passing a three-phase armature current through the U, V, and W phase coils 31A, and the mover 32 is moved linearly with respect to the stator 31. Move to The linear motor 30 is provided with a linear encoder 38 for detecting the relative position of the mover 32 with respect to the stator 31. Instead of the above configuration, a permanent magnet may be provided on the stator 31 and a plurality of coils may be provided on the mover 32.
　直動モータ３０の可動子３２と回転モータ２０の固定子２２とは、直動テーブル３３を介して連結されている。直動テーブル３３は、直動モータ３０の可動子３２の移動に伴って移動可能である。直動テーブル３３の移動は、直動案内装置３４によってＺ軸方向に案内されている。直動案内装置３４は、ハウジング２に固定されたレール３４Ａと、レール３４Ａに組み付けられたスライダブロック３４Ｂとを有する。レール３４Ａは、Ｚ軸方向に延びており、スライダブロック３４Ｂは、レール３４Ａに沿ってＺ軸方向に移動可能に構成されている。 可 動 The mover 32 of the linear motor 30 and the stator 22 of the rotary motor 20 are connected via a linear table 33. The translation table 33 is movable with the movement of the mover 32 of the translation motor 30. The translation table 33 is guided by the translation guide device 34 in the Z-axis direction. The linear motion guide device 34 has a rail 34A fixed to the housing 2 and a slider block 34B assembled to the rail 34A. The rail 34A extends in the Z-axis direction, and the slider block 34B is configured to be movable in the Z-axis direction along the rail 34A.
　直動テーブル３３は、スライダブロック３４Ｂに固定されており、スライダブロック３４Ｂと共にＺ軸方向に移動可能である。直動テーブル３３は、直動モータ３０の可動子３２と２つの連結アーム３５を介して連結されている。２つの連結アーム３５は、可動子３２のＺ軸方向の両端部と、直動テーブル３３のＺ軸方向の両端部とを連結している。また、直動テーブル３３は、両端部よりも中央側において、２つの連結アーム３６を介して回転モータ２０の固定子２２と連結されている。なお、Ｚ軸方向上側の連結アーム３６を第一アーム３６Ａといい、Ｚ軸方向下側の連結アーム３６を第二アーム３６Ｂという。また、第一アーム３６Ａと第二アーム３６Ｂとを区別しない場合には、単に連結アーム３６という。直動テーブル３３と回転モータ２０の固定子２２とが、該連結アーム３６を介して回転モータ２０の固定子２２と連結されているために、直動テーブル３３の移動に伴って回転モータ２０の固定子２２も移動する。また、連結アーム３６は、断面が四角である。各連結アーム３６におけるＺ軸方向の上側を向く面には、ひずみゲージ３７が固定されている。なお、第一アーム３６Ａに固定されるひずみゲージ３７を第一ひずみゲージ３７Ａといい、第二アーム３６Ｂに固定されるひずみゲージ３７を第二ひずみゲージ３７Ｂという。第一ひずみゲージ３７Ａと第二ひずみゲージ３７Ｂとを区別しない場合には、単にひずみゲージ３７という。なお、本実施形態の２つのひずみゲージ３７は、連結アーム３６のＺ軸方向の上側を向く面に夫々設けられているが、これに代えて、連結アーム３６のＺ軸方向の下側を向く面に夫々設けられていてもよい。 The linear motion table 33 is fixed to the slider block 34B, and is movable in the Z-axis direction together with the slider block 34B. The translation table 33 is connected to the mover 32 of the translation motor 30 via two connection arms 35. The two connecting arms 35 connect both ends of the mover 32 in the Z-axis direction and both ends of the linear motion table 33 in the Z-axis direction. Further, the linear motion table 33 is connected to the stator 22 of the rotary motor 20 via two connection arms 36 on the center side of both ends. The upper connecting arm 36 in the Z-axis direction is referred to as a first arm 36A, and the lower connecting arm 36 in the Z-axis direction is referred to as a second arm 36B. When the first arm 36A and the second arm 36B are not distinguished, they are simply referred to as the connecting arm 36. Since the linear motion table 33 and the stator 22 of the rotary motor 20 are connected to the stator 22 of the rotary motor 20 via the connection arm 36, the rotation of the rotary motor 20 The stator 22 also moves. The connecting arm 36 has a square cross section. A strain gauge 37 is fixed to a surface of each connecting arm 36 facing upward in the Z-axis direction. The strain gauge 37 fixed to the first arm 36A is called a first strain gauge 37A, and the strain gauge 37 fixed to the second arm 36B is called a second strain gauge 37B. When the first strain gauge 37A and the second strain gauge 37B are not distinguished, they are simply referred to as strain gauges 37. Note that the two strain gauges 37 of the present embodiment are respectively provided on the surfaces of the connection arms 36 that face upward in the Z-axis direction. Instead, the two strain gauges 37 face downward of the connection arms 36 in the Z-axis direction. Each may be provided on the surface.
　エア制御機構６０は、シャフト１０の先端部１０Ａに正圧や負圧を発生させるための機構である。すなわち、エア制御機構６０は、ワークＷのピックアップ時において、シャフト１０内の空気を吸引することで、該シャフト１０の先端部１０Ａに負圧を発生させる。これによってワークＷがシャフト１０の先端部１０Ａに吸い付けられる。また、シャフト１０内に空気を送り込むことで、該シャフト１０の先端部１０Ａに正圧を発生させる。これによりシャフト１０の先端部１０ＡからワークＷを容易に脱離させる。 The air control mechanism 60 is a mechanism for generating a positive pressure or a negative pressure at the tip 10A of the shaft 10. That is, the air control mechanism 60 generates a negative pressure at the distal end portion 10A of the shaft 10 by sucking the air in the shaft 10 when the work W is picked up. Thereby, the work W is sucked to the tip portion 10A of the shaft 10. Further, by sending air into the shaft 10, a positive pressure is generated at the distal end 10 </ b> A of the shaft 10. Thereby, the work W is easily detached from the tip portion 10A of the shaft 10.
　エア制御機構６０は、正圧の空気が流通する正圧通路６１Ａ（一点鎖線参照。）と、負圧の空気が流通する負圧通路６１Ｂ（二点鎖線参照。）と、正圧の空気及び負圧の空気で共用される共用通路６１Ｃ（破線参照。）とを有する。正圧通路６１Ａの一端は、ハウジング２のＺ軸方向の上端面２０１に設けられた正圧用コネクタ６２Ａに接続され、正圧通路６１Ａの他端は正圧用の電磁弁（以下、正圧電磁弁６３Ａという。）に接続されている。正圧電磁弁６３Ａは、後述するコントローラ７によって開閉される。なお、正圧通路６１Ａの一端側の部分はチューブ６１０によって構成され、他端側の部分はブロック６００に開けられた穴により構成されている。正圧用コネクタ６２Ａは、ハウジング２のＺ軸方向の上端面２０１を貫通しており、正圧用コネクタ６２Ａにはエアを吐出するポンプ等に繋がるチューブが外部から接続される。 The air control mechanism 60 includes a positive pressure passage 61A (see a dashed line) through which positive-pressure air flows, a negative pressure passage 61B (see a two-dot chain line) through which negative-pressure air flows, and positive-pressure air and air. And a shared passage 61C (see broken line) shared by the negative pressure air. One end of the positive pressure passage 61A is connected to a positive pressure connector 62A provided on the upper end surface 201 in the Z-axis direction of the housing 2, and the other end of the positive pressure passage 61A is connected to a positive pressure solenoid valve (hereinafter, a positive pressure solenoid valve). 63A). The positive pressure solenoid valve 63A is opened and closed by a controller 7 described later. Note that a portion on one end side of the positive pressure passage 61 </ b> A is configured by the tube 610, and a portion on the other end side is configured by a hole formed in the block 600. The positive pressure connector 62A passes through the upper end surface 201 of the housing 2 in the Z-axis direction, and a tube connected to a pump or the like that discharges air is connected to the positive pressure connector 62A from the outside.
　負圧通路６１Ｂの一端は、ハウジング２のＺ軸方向の上端面２０１に設けられた負圧用コネクタ６２Ｂに接続され、負圧通路６１Ｂの他端は負圧用の電磁弁（以下、負圧電磁弁６３Ｂという。）に接続されている。負圧電磁弁６３Ｂは、後述するコントローラ７によって開閉される。なお、負圧通路６１Ｂの一端側の部分はチューブ６２０によって構成され、他端側の部分はブロック６００に開けられた穴により構成されている。負圧用コネクタ６２Ｂは、ハウジング２のＺ軸方向の上端面２０１を貫通しており、負圧用コネクタ６２Ｂにはエアを吸引するポンプ等に繋がるチューブが外部から接続される。 One end of the negative pressure passage 61B is connected to a negative pressure connector 62B provided on the upper end surface 201 in the Z-axis direction of the housing 2, and the other end of the negative pressure passage 61B is connected to a negative pressure solenoid valve (hereinafter, a negative pressure solenoid valve). 63B). The negative pressure solenoid valve 63B is opened and closed by a controller 7 described later. The one end of the negative pressure passage 61B is constituted by a tube 620, and the other end is constituted by a hole formed in the block 600. The negative pressure connector 62B penetrates through the upper end surface 201 of the housing 2 in the Z-axis direction, and a tube connected to a pump or the like that sucks air is connected to the negative pressure connector 62B from outside.
　共用通路６１Ｃはブロック６００に開けられた穴により構成されている。共用通路６１Ｃの一端は、２つに分岐して正圧電磁弁６３Ａ及び負圧電磁弁６３Ｂに接続されており、共用通路６１Ｃの他端は、ハウジング２に形成されている貫通孔であるエア流通路２０２Ａに接続されている。エア流通路２０２Ａは、シャフトハウジング５０に通じている。負圧電磁弁６３Ｂを開き且つ正圧電磁弁６３Ａを閉じることにより、負圧通路６１Ｂと共用通路６１Ｃとが連通されるため、共用通路６１Ｃ内に負圧が発生する。そうすると、エア流通路２０２Ａを介してシャフトハウジング５０内から空気が吸引される。一方、正圧電磁弁６３Ａを開き且つ負圧電磁弁６３Ｂを閉じることにより、正圧通路６１Ａと共用通路６１Ｃとが連通されるため、共用通路６１Ｃ内に正圧が発生する。そうすると、エア流通路２０２Ａを介してシャフトハウジング５０内に空気が供給される。共用通路６１Ｃには、共用通路６１Ｃ内の空気の圧力を検出する圧力センサ６４及び共用通路６１Ｃ内の空気の流量を検出する流量センサ６５が設けられている。 The common passage 61C is constituted by a hole formed in the block 600. One end of the common passage 61C branches into two and is connected to the positive pressure solenoid valve 63A and the negative pressure solenoid valve 63B. The other end of the common passage 61C is an air which is a through hole formed in the housing 2. It is connected to the flow passage 202A. The air flow passage 202A communicates with the shaft housing 50. By opening the negative pressure electromagnetic valve 63B and closing the positive pressure electromagnetic valve 63A, the negative pressure passage 61B and the common passage 61C communicate with each other, so that a negative pressure is generated in the common passage 61C. Then, air is sucked from the inside of the shaft housing 50 through the air flow passage 202A. On the other hand, by opening the positive pressure solenoid valve 63A and closing the negative pressure solenoid valve 63B, the positive pressure passage 61A and the common passage 61C communicate with each other, so that a positive pressure is generated in the common passage 61C. Then, air is supplied into the shaft housing 50 via the air flow passage 202A. The common passage 61C is provided with a pressure sensor 64 for detecting the pressure of the air in the common passage 61C and a flow sensor 65 for detecting the flow rate of the air in the common passage 61C.
　なお、図２に示したアクチュエータ１では、正圧通路６１Ａ及び負圧通路６１Ｂの一部がチューブで構成され、他部がブロック６００に開けられた穴により構成されているが、これに限らず、全ての通路をチューブで構成することもできるし、全ての通路をブロック６００に開けられた穴により構成することもできる。共用通路６１Ｃについても同様で、全てチューブで構成することもできるし、チューブを併用して構成することもできる。なお、チューブ６１０及びチューブ６２０の材料は、樹脂等の柔軟性を有する材料であってもよく、金属等の柔軟性を有さない材料であってもよい。また、正圧通路６１Ａを用いてシャフトハウジング５０に正圧を供給する代わりに、大気圧を供給してもよい。 In the actuator 1 shown in FIG. 2, a part of the positive pressure passage 61A and the negative pressure passage 61B is formed by a tube, and the other part is formed by a hole formed in the block 600. However, the present invention is not limited to this. , All the passages can be constituted by tubes, or all the passages can be constituted by holes formed in the block 600. The same applies to the common passage 61C. All of the common passages can be constituted by tubes, or can be constituted by using tubes in combination. In addition, the material of the tube 610 and the tube 620 may be a material having flexibility such as resin, or may be a material having no flexibility such as metal. Further, instead of supplying a positive pressure to the shaft housing 50 using the positive pressure passage 61A, an atmospheric pressure may be supplied.
　また、ハウジング２のＺ軸方向の上端面２０１には、回転モータ２０を冷却するための空気の入口となるコネクタ（以下、入口コネクタ９１Ａという。）およびハウジング２からの空気の出口となるコネクタ（以下、出口コネクタ９１Ｂという。）が設けられている。入口コネクタ９１Ａ及び出口コネクタ９１Ｂは、夫々空気が流通可能なようにハウジング２の上端面２０１を貫通している。入口コネクタ９１Ａにはエアを吐出するポンプ等に繋がるチューブがハウジング２の外部から接続され、出口コネクタ９１Ｂにはハウジング２から流出するエアを排出するチューブがハウジング２の外部から接続される。ハウジング２の内部には、回転モータ２０を冷却するための空気が流通する金属製のパイプ（以下、冷却パイプ９２という。）が設けられており、この冷却パイプ９２の一端は、入口コネクタ９１Ａに接続されている。冷却パイプ９２は、入口コネクタ９１ＡからＺ軸方向にハウジング２の下端面２０２付近まで延び、該下端面２０２付近において湾曲して他端側が回転モータ２０に向くように形成されている。このように、Ｚ軸方向の下側からハウジング２内に空気を供給することにより、効率的な冷却が可能となる。また、冷却パイプ９２は、直動モータ３０のコイル３１Ａから熱を奪うように、該固定子３１の内部を貫通している。固定子３１に設けられているコイル３１Ａからより多くの熱を奪うように、冷却パイプ９２の周りにコイル３１Ａが配置されている。 A connector (hereinafter, referred to as an inlet connector 91A) serving as an air inlet for cooling the rotary motor 20 and a connector (hereinafter, referred to as an inlet connector 91A) serving as an outlet for air from the housing 2 are provided on the upper end surface 201 of the housing 2 in the Z-axis direction. Hereinafter, this is referred to as an outlet connector 91B). The inlet connector 91A and the outlet connector 91B pass through the upper end surface 201 of the housing 2 so that air can flow therethrough. A tube connected to a pump or the like that discharges air is connected to the inlet connector 91A from the outside of the housing 2, and a tube that discharges air flowing out of the housing 2 is connected to the outlet connector 91B from the outside of the housing 2. A metal pipe (hereinafter, referred to as a cooling pipe 92) through which air for cooling the rotary motor 20 flows is provided inside the housing 2, and one end of the cooling pipe 92 is connected to the inlet connector 91A. It is connected. The cooling pipe 92 extends from the inlet connector 91 </ b> A in the Z-axis direction to a position near the lower end surface 202 of the housing 2, is curved near the lower end surface 202, and is formed so that the other end faces the rotary motor 20. By supplying air into the housing 2 from the lower side in the Z-axis direction, efficient cooling is possible. Further, the cooling pipe 92 penetrates through the inside of the stator 31 so as to remove heat from the coil 31A of the linear motor 30. The coil 31A is arranged around the cooling pipe 92 so as to remove more heat from the coil 31A provided on the stator 31.
　ハウジング２のＺ軸方向の上端面２０１には、電力を供給する電線や信号線を含んだコネクタ４１が接続されている。また、ハウジング２には、コントローラ７が設けられている。コネクタ４１からハウジング２内に引き込まれる電線や信号線は、コントローラ７に接続されている。コントローラ７には、ＣＰＵ（Central Processing Unit）、ＲＡＭ（Random Access Memory）、ＲＯＭ（Read Only Memory）、ＥＰＲＯＭ（Erasable Programmable ROM）が備わり、これらはバスにより相互に接続される。ＥＰＲＯＭには、各種プログラム、各種テーブル等が格納される。ＥＰＲＯＭに格納されたプログラムをＣＰＵがＲＡＭの作業領域にロードして実行し、このプログラムの実行を通じて、回転モータ２０、直動モータ３０、正圧電磁弁６３Ａ、負圧電磁弁６３Ｂ等が制御される。これにより、所定の目的に合致した機能をＣＰＵが実現する。また、圧力センサ６４、流量センサ６５、ひずみゲージ３７、ロータリエンコーダ２４、リニアエンコーダ３８の出力信号がコントローラ７に入力される。 コ ネ ク タ A connector 41 including an electric wire for supplying electric power and a signal line is connected to the upper end surface 201 of the housing 2 in the Z-axis direction. The housing 2 is provided with a controller 7. Electric wires and signal lines drawn into the housing 2 from the connector 41 are connected to the controller 7. The controller 7 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an EPROM (Erasable Programmable ROM), which are interconnected by a bus. The EPROM stores various programs, various tables, and the like. The CPU loads the program stored in the EPROM into the work area of the RAM and executes the program. Through the execution of the program, the rotation motor 20, the direct drive motor 30, the positive pressure solenoid valve 63A, the negative pressure solenoid valve 63B, and the like are controlled. You. As a result, the CPU realizes a function that meets a predetermined purpose. Further, output signals of the pressure sensor 64, the flow sensor 65, the strain gauge 37, the rotary encoder 24, and the linear encoder 38 are input to the controller 7.
　図３は、シャフトハウジング５０とシャフト１０の先端部１０Ａとの概略構成を示した断面図である。シャフトハウジング５０は、ハウジング本体５１と、２つのリング５２と、フィルタ５３と、フィルタ止め５４とを有する。ハウジング本体５１には、シャフト１０が挿通される貫通孔５１Ａが形成されている。貫通孔５１Ａは、Ｚ軸方向にハウジング本体５１を貫通しており、該貫通孔５１ＡのＺ軸方向の上端は、ハウジング２に形成された貫通孔２Ａに通じている。貫通孔５１Ａの直径はシャフト１０の外径よりも大きい。そのため、貫通孔５１Ａの内面とシャフト１０の外面とには隙間が設けられている。貫通孔５１Ａの両端部には、孔の直径が拡大された拡径部５１Ｂが設けられている。２つの拡径部５１Ｂには、夫々リング５２が嵌め込まれている。リング５２は筒状に形成されており、リング５２の内径はシャフト１０の外径よりも若干大きい。したがって、シャフト１０がリング５２の内部をＺ軸方向に移動可能である。そのため、リング５２の内面とシャフト１０の外面との間にも隙間が形成される。したがって、シャフト１０がリング５２の内部をＺ軸方向に移動可能であり、且つ、シャフト１０がリング５２の内部を中心軸１００回りに回転可能である。ただし、拡径部５１Ｂを除く貫通孔５１Ａの内面とシャフト１０の外面との間に形成される隙間よりも、リング５２の内面とシャフト１０の外面との間に形成される隙間の方が小さい。なお、Ｚ軸方向上側のリング５２を第一リング５２Ａといい、Ｚ軸方向下側のリング５２を第二リング５２Ｂという。第一リング５２Ａと第二リング５２Ｂとを区別しない場合には、単にリング５２という。リング５２の材料には、例えば金属または樹脂を用いることができる。 FIG. 3 is a cross-sectional view showing a schematic configuration of the shaft housing 50 and the tip 10A of the shaft 10. As shown in FIG. The shaft housing 50 has a housing body 51, two rings 52, a filter 53, and a filter stopper 54. The housing body 51 has a through hole 51A through which the shaft 10 is inserted. The through-hole 51A penetrates the housing body 51 in the Z-axis direction, and an upper end of the through-hole 51A in the Z-axis direction communicates with a through-hole 2A formed in the housing 2. The diameter of the through hole 51A is larger than the outer diameter of the shaft 10. Therefore, a gap is provided between the inner surface of the through hole 51A and the outer surface of the shaft 10. Both ends of the through hole 51A are provided with enlarged diameter portions 51B in which the diameter of the hole is enlarged. Rings 52 are fitted into the two enlarged diameter portions 51B, respectively. The ring 52 is formed in a cylindrical shape, and the inner diameter of the ring 52 is slightly larger than the outer diameter of the shaft 10. Therefore, the shaft 10 can move inside the ring 52 in the Z-axis direction. Therefore, a gap is also formed between the inner surface of the ring 52 and the outer surface of the shaft 10. Therefore, the shaft 10 can move inside the ring 52 in the Z-axis direction, and the shaft 10 can rotate around the central axis 100 inside the ring 52. However, the gap formed between the inner surface of the ring 52 and the outer surface of the shaft 10 is smaller than the gap formed between the inner surface of the through hole 51A excluding the enlarged diameter portion 51B and the outer surface of the shaft 10. . The upper ring 52 in the Z-axis direction is referred to as a first ring 52A, and the lower ring 52 in the Z-axis direction is referred to as a second ring 52B. When the first ring 52A and the second ring 52B are not distinguished, they are simply referred to as the ring 52. As the material of the ring 52, for example, metal or resin can be used.
　ハウジング本体５１のＺ軸方向の中央部には、Ｘ軸方向の左右両方向に張り出した張出部５１１が形成されている。張出部５１１には、ハウジング２の下端面２０２と平行な面であって、シャフトハウジング５０をハウジング２の下端面２０２へ取り付けるときに、該下端面２０２と接する面である取付面５１１Ａが形成されている。取付面５１１Ａは、中心軸１００と直交する面である。また、ハウジング２にシャフトハウジング５０を取り付けたときに、シャフトハウジング５０の一部であって取付面５１１ＡよりもＺ軸方向の上側の部分５１２は、ハウジング２に形成された凹部２０２Ｂに嵌るように形成されている。 張 At the center of the housing body 51 in the Z-axis direction, an overhang portion 511 is formed which extends in both the left and right directions in the X-axis direction. The overhang portion 511 has a mounting surface 511A that is a surface parallel to the lower end surface 202 of the housing 2 and that comes into contact with the lower end surface 202 when the shaft housing 50 is mounted on the lower end surface 202 of the housing 2. Have been. The mounting surface 511A is a surface orthogonal to the central axis 100. When the shaft housing 50 is attached to the housing 2, a part 512 of the shaft housing 50, which is above the attachment surface 511 </ b> A in the Z-axis direction, fits into the concave portion 202 </ b> B formed in the housing 2. Is formed.
　上記のとおり、貫通孔５１Ａの内面とシャフト１０の外面とには隙間が設けられている。その結果、ハウジング本体５１の内部には、貫通孔５１Ａの内面と、シャフト１０の外面と、第一リング５２Ａの下端面と、第二リング５２Ｂの上端面とによって囲まれた空間である内部空間５００が形成されている。また、シャフトハウジング５０には、ハウジング２の下端面２０２に形成されるエア流通路２０２Ａの開口部と、内部空間５００とを連通して空気の通路となる制御通路５０１が形成されている。制御通路５０１は、Ｘ軸方向に延びる第一通路５０１Ａ、Ｚ軸方向に延びる第二通路５０１Ｂ、第一通路５０１Ａ及び第二通路５０１Ｂが接続される空間であってフィルタ５３が配置される空間であるフィルタ部５０１Ｃを有する。第一通路５０１Ａの一端は内部空間５００に接続され、他端はフィルタ部５０１Ｃに接続されている。第二通路５０１Ｂの一端は、取付面５１１Ａに開口しており、エア流通路２０２Ａの開口部に接続されるように位置が合わされている。 As described above, a gap is provided between the inner surface of the through hole 51A and the outer surface of the shaft 10. As a result, inside the housing body 51, an inner space that is a space surrounded by the inner surface of the through hole 51A, the outer surface of the shaft 10, the lower end surface of the first ring 52A, and the upper end surface of the second ring 52B. 500 are formed. In the shaft housing 50, a control passage 501 is formed, which communicates with an opening of an air flow passage 202A formed in the lower end surface 202 of the housing 2 and the internal space 500 to serve as an air passage. The control passage 501 is a space in which the first passage 501A extending in the X-axis direction, the second passage 501B extending in the Z-axis direction, the first passage 501A and the second passage 501B are connected, and in which the filter 53 is arranged. It has a certain filter section 501C. One end of the first passage 501A is connected to the internal space 500, and the other end is connected to the filter unit 501C. One end of the second passage 501B is open to the mounting surface 511A, and is positioned so as to be connected to the opening of the air flow passage 202A.
　また、第二通路５０１Ｂの他端はフィルタ部５０１Ｃに接続される。フィルタ部５０１Ｃには、円筒状に形成されたフィルタ５３が設けられている。フィルタ部５０１Ｃは、第一通路５０１Ａと中心軸が一致するようにＸ軸方向に延びた円柱形状の空間となるように形成されている。フィルタ部５０１Ｃの内径とフィルタ５３の外径とは略等しい。フィルタ５３は、Ｘ軸方向にフィルタ部５０１Ｃへ挿入される。フィルタ部５０１Ｃにフィルタ５３が挿入された後に、フィルタ止め５４によってフィルタ５３の挿入口となったフィルタ部５０１Ｃの端部が閉塞される。第二通路５０１Ｂの他端は、フィルタ５３の外周面側からフィルタ部５０１Ｃに接続されている。また、第一通路５０１Ａの他端はフィルタ５３の中心側と通じている。そのため、第一通路５０１Ａと第二通路５０１Ｂとの間を流通する空気は、フィルタ５３を通過する。したがって、例えば、先端部１０Ａに負圧を発生させたときに、内部空間５００に空気と一緒に異物を吸い込んだとしても、この異物はフィルタ５３によって捕集される。第二通路５０１Ｂの一端には、シール剤を保持するように溝５０１Ｄが形成されている。 他 端 The other end of the second passage 501B is connected to the filter 501C. The filter unit 501C is provided with a filter 53 formed in a cylindrical shape. The filter portion 501C is formed so as to be a cylindrical space extending in the X-axis direction so that the center axis of the first passage 501A coincides with the center axis. The inner diameter of the filter portion 501C is substantially equal to the outer diameter of the filter 53. The filter 53 is inserted into the filter unit 501C in the X-axis direction. After the filter 53 is inserted into the filter unit 501C, the filter stopper 54 closes the end of the filter unit 501C that has become the insertion port of the filter 53. The other end of the second passage 501B is connected to the filter section 501C from the outer peripheral surface side of the filter 53. The other end of the first passage 501A communicates with the center of the filter 53. Therefore, the air flowing between the first passage 501A and the second passage 501B passes through the filter 53. Therefore, for example, even when foreign matter is sucked into the internal space 500 together with air when a negative pressure is generated at the distal end portion 10A, the foreign matter is collected by the filter 53. A groove 501D is formed at one end of the second passage 501B so as to hold the sealant.
　張出部５１１のＸ軸方向の両端部付近には、該シャフトハウジング５０をハウジング２にボルトを用いて固定するときに、該ボルトを挿通させるボルト孔５１Ｇが２つ形成されている。ボルト孔５１Ｇは、Ｚ軸方向に張出部５１１を貫通して取付面５１１Ａに開口している。 In the vicinity of both ends in the X-axis direction of the protruding portion 511, two bolt holes 51G through which the bolts are inserted when the shaft housing 50 is fixed to the housing 2 using bolts are formed. The bolt hole 51G penetrates the projecting portion 511 in the Z-axis direction and opens on the mounting surface 511A.
　シャフト１０の先端部１０Ａ側には、シャフト１０が中空となるように中空部１１が形成されている。中空部１１の一端は、先端部１０Ａで開口している。また、中空部１１の他端には、内部空間５００と中空部１１とをＸ軸方向に連通する連通孔１２が形成されている。直動モータ３０によってシャフト１０がＺ軸方向に移動したときのストロークの全範囲において、内部空間５００と中空部１１とが連通するように連通孔１２が形成されている。したがって、シャフト１０の先端部１０Ａと、エア制御機構６０とは、中空部１１、連通孔１２、内部空間５００、制御通路５０１、エア流通路２０２Ａを介して連通している。なお、連通孔１２は、Ｘ軸方向に加えてＹ軸方向にも形成されていてもよい。 中空 A hollow portion 11 is formed on the tip 10A side of the shaft 10 so that the shaft 10 becomes hollow. One end of the hollow part 11 is open at the tip part 10A. At the other end of the hollow portion 11, a communication hole 12 that connects the internal space 500 and the hollow portion 11 in the X-axis direction is formed. The communication hole 12 is formed such that the internal space 500 and the hollow portion 11 communicate with each other over the entire range of the stroke when the shaft 10 is moved in the Z-axis direction by the linear motor 30. Therefore, the distal end portion 10A of the shaft 10 and the air control mechanism 60 communicate with each other through the hollow portion 11, the communication hole 12, the internal space 500, the control passage 501, and the air flow passage 202A. The communication hole 12 may be formed in the Y-axis direction in addition to the X-axis direction.
　このような構成によれば、直動モータ３０を駆動してシャフト１０をＺ軸方向に移動させたときに、シャフト１０がＺ軸方向のどの位置にあっても、連通孔１２は常に内部空間５００と中空部１１とを連通する。また、回転モータ２０を駆動してシャフト１０を中心軸１００回りに回転させたときに、シャフト１０の回転角度が中心軸１００回りのどの角度であっても、連通孔１２は常に内部空間５００と中空部１１とを連通する。したがって、シャフト１０がどのような状態であっても、中空部１１と内部空間５００との連通状態が維持されるため、中空部１１は常にエア制御機構６０に通じていることになる。そのため、シャフト１０の位置にかかわらず、エア制御機構６０において正圧電磁弁６３Ａを閉じ、負圧電磁弁６３Ｂを開くと、エア流通路２０２Ａ、制御通路５０１、内部空間５００、および連通孔１２を介して、中空部１１内の空気が吸引されることになる。その結果、中空部１１に負圧を発生させることができる。すなわち、シャフト１０の先端部１０Ａに負圧を発生させることができるので、シャフト１０の先端部１０ＡにワークＷを吸い付けることができる。なお、上述したように、リング５２の内面とシャフト１０の外面との間にも隙間が形成されている。しかしながら、この隙間は、内部空間５００を形成する隙間（すなわち、貫通孔５１Ａの内面とシャフト１０の外面との間に形成される隙間）よりも小さい。そのため、エア制御機構６０において正圧電磁弁６３Ａを閉じ、負圧電磁弁６３Ｂを開くことで、内部空間５００内から空気が吸引されても、リング５２の内面とシャフト１０の外面との間の隙間を流通する空気の流量を抑制することができる。これにより、ワークＷをピックアップできるような負圧をシャフト１０の先端部１０Ａに発生させることができる。一方、シャフト１０の位置にかかわらず、エア制御機構６０において正圧電磁弁６３Ａを開き、負圧電磁弁６３Ｂを閉じると、中空部１１に正圧を発生させることができる。すなわち、シャフト１０の先端部１０Ａに正圧を発生させることができるので、シャフト１０の先端部１０ＡからワークＷを速やかに脱離させることができる。 According to such a configuration, when the linear motor 30 is driven to move the shaft 10 in the Z-axis direction, the communication hole 12 is always in the internal space regardless of the position of the shaft 10 in the Z-axis direction. 500 and the hollow portion 11 are communicated. Further, when the rotation motor 20 is driven to rotate the shaft 10 around the central axis 100, the communication hole 12 is always in contact with the internal space 500 regardless of the rotation angle of the shaft 10 around the central axis 100. The hollow portion 11 is communicated. Therefore, regardless of the state of the shaft 10, the communication between the hollow portion 11 and the internal space 500 is maintained, so that the hollow portion 11 always communicates with the air control mechanism 60. Therefore, regardless of the position of the shaft 10, when the positive pressure solenoid valve 63A is closed and the negative pressure solenoid valve 63B is opened in the air control mechanism 60, the air flow passage 202A, the control passage 501, the internal space 500, and the communication hole 12 are closed. Through this, the air in the hollow portion 11 is sucked. As a result, a negative pressure can be generated in the hollow portion 11. That is, since a negative pressure can be generated at the tip 10A of the shaft 10, the workpiece W can be sucked to the tip 10A of the shaft 10. As described above, a gap is also formed between the inner surface of the ring 52 and the outer surface of the shaft 10. However, this gap is smaller than the gap forming the internal space 500 (that is, the gap formed between the inner surface of the through hole 51A and the outer surface of the shaft 10). Therefore, by closing the positive pressure solenoid valve 63A and opening the negative pressure solenoid valve 63B in the air control mechanism 60, even if air is sucked from the interior space 500, the air gap between the inner surface of the ring 52 and the outer surface of the shaft 10 is maintained. The flow rate of the air flowing through the gap can be suppressed. Thereby, a negative pressure capable of picking up the work W can be generated at the distal end portion 10A of the shaft 10. On the other hand, regardless of the position of the shaft 10, when the positive pressure electromagnetic valve 63A is opened and the negative pressure electromagnetic valve 63B is closed in the air control mechanism 60, a positive pressure can be generated in the hollow portion 11. That is, since a positive pressure can be generated at the tip 10A of the shaft 10, the workpiece W can be quickly detached from the tip 10A of the shaft 10.
　（ピックアンドプレイス動作）
　アクチュエータ１を用いたワークＷのピックアンドプレイスについて説明する。ピックアンドプレイスは、コントローラ７が所定のプログラムを実行することにより行われる。ワークＷのピックアップ時において、シャフト１０がワークＷに接触するまでは、正圧電磁弁６３Ａ及び負圧電磁弁６３Ｂは共に閉じた状態とする。この場合、シャフト１０の先端部１０Ａの圧力は大気圧となる。そして、直動モータ３０によりシャフト１０をＺ軸方向下側に移動させる。シャフト１０がワークＷに接触すると、直動モータ３０を停止させる。直動モータ３０を停止後に負圧電磁弁６３Ｂを開くことにより、シャフト１０の先端部１０Ａに負圧を発生させ、ワークＷをシャフト１０の先端部１０Ａに吸い付ける。その後、直動モータ３０によりシャフト１０をＺ軸方向上側に移動させる。このときに、必要に応じて、回転モータ２０によりシャフト１０を回転させる。このようにして、ワークＷをピックアップすることができる。 (Pick and place operation)
The pick and place of the work W using the actuator 1 will be described. The pick and place is performed by the controller 7 executing a predetermined program. At the time of picking up the work W, the positive pressure solenoid valve 63A and the negative pressure solenoid valve 63B are both closed until the shaft 10 comes into contact with the work W. In this case, the pressure at the distal end 10A of the shaft 10 becomes the atmospheric pressure. Then, the shaft 10 is moved downward in the Z-axis direction by the linear motor 30. When the shaft 10 comes into contact with the workpiece W, the linear motor 30 is stopped. By opening the negative pressure solenoid valve 63B after stopping the linear motor 30, a negative pressure is generated at the distal end 10A of the shaft 10, and the work W is sucked to the distal end 10A of the shaft 10. Thereafter, the shaft 10 is moved upward in the Z-axis direction by the linear motor 30. At this time, the shaft 10 is rotated by the rotation motor 20 as necessary. Thus, the work W can be picked up.
　次に、ワークＷのプレイス時には、ワークＷが先端部１０Ａに吸い付いている状態のシャフト１０を直動モータ３０によりＺ軸方向の下側に移動させる。ワークＷが接地すると、直動モータ３０を停止させることで、シャフト１０の移動を停止させる。さらに、負圧電磁弁６３Ｂを閉じ且つ正圧電磁弁６３Ａを開くことにより、シャフト１０の先端部１０Ａに正圧を発生させる。その後、直動モータ３０によりシャフト１０をＺ軸方向の上側に移動させることにより、シャフト１０の先端部１０ＡがワークＷから離れる。 Next, at the time of placing the work W, the shaft 10 in a state where the work W is attracted to the distal end portion 10A is moved downward by the linear motor 30 in the Z-axis direction. When the work W comes into contact with the ground, the movement of the shaft 10 is stopped by stopping the linear motor 30. Further, by closing the negative pressure electromagnetic valve 63B and opening the positive pressure electromagnetic valve 63A, a positive pressure is generated at the tip 10A of the shaft 10. Thereafter, the distal end portion 10A of the shaft 10 is separated from the workpiece W by moving the shaft 10 upward in the Z-axis direction by the linear motor 30.
　ここで、ワークＷのピックアップ時において、シャフト１０の先端部１０ＡがワークＷに接触したことをひずみゲージ３７を用いて検出する。以下では、この方法について説明する。なお、ワークＷのプレイス時においてワークＷが接地したことも同様にして検出することができる。シャフト１０の先端部１０ＡがワークＷに接触して先端部１０ＡがワークＷを押すと、シャフト１０とワークＷとの間に荷重が発生する。すなわち、シャフト１０がワークＷに力を加えたときの反作用によって、シャフト１０がワークＷから力を受ける。このシャフト１０がワークＷから受ける力は、連結アーム３６に対してひずみを発生させる方向に作用する。すなわち、このときに連結アーム３６にひずみが生じる。このひずみは、ひずみゲージ３７によって検出される。そして、ひずみゲージ３７が検出するひずみは、シャフト１０がワークＷから受ける力と相関関係にある。このため、ひずみゲージ３７の検出値に基づいて、ワークＷからシャフト１０が受ける力、すなわち、シャフト１０とワークＷとの間に発生した荷重を検出することができる。ひずみゲージの検出値と荷重との関係は予め実験またはシミュレーション等により求めることができる。 Here, when the work W is picked up, the fact that the tip 10A of the shaft 10 has come into contact with the work W is detected using the strain gauge 37. Hereinafter, this method will be described. In addition, it can be similarly detected that the work W is grounded when the work W is placed. When the tip 10A of the shaft 10 contacts the work W and the tip 10A pushes the work W, a load is generated between the shaft 10 and the work W. That is, the shaft 10 receives a force from the work W due to a reaction when the shaft 10 applies a force to the work W. The force that the shaft 10 receives from the work W acts in a direction that generates strain on the connecting arm 36. That is, at this time, the connection arm 36 is distorted. This strain is detected by the strain gauge 37. The strain detected by the strain gauge 37 has a correlation with the force that the shaft 10 receives from the workpiece W. For this reason, based on the detection value of the strain gauge 37, the force that the shaft 10 receives from the work W, that is, the load generated between the shaft 10 and the work W can be detected. The relationship between the detected value of the strain gauge and the load can be obtained in advance by experiment, simulation, or the like.
　このように、ひずみゲージ３７の検出値に基づいてシャフト１０とワークＷとの間に発生した荷重を検出することができるため、例えば、荷重が発生した時点でシャフト１０の先端部１０ＡがワークＷに接触したと判断してもよいし、誤差等の影響を考慮して、検出された荷重が所定荷重以上の場合に、シャフト１０の先端部１０ＡがワークＷに接触したと判断してもよい。なお、所定荷重は、シャフト１０がワークＷに接触したと判定される閾値である。また、所定荷重をワークＷの破損を抑制しつつワークＷをより確実にピックアップすることが可能な荷重として設定してもよい。また、所定荷重は、ワークＷの種類に応じて変更することもできる。 As described above, since the load generated between the shaft 10 and the work W can be detected based on the detection value of the strain gauge 37, for example, when the load is generated, the tip 10A of the shaft 10 May be determined, or when the detected load is equal to or more than a predetermined load in consideration of the influence of an error or the like, it may be determined that the distal end portion 10A of the shaft 10 has contacted the workpiece W. . The predetermined load is a threshold value at which it is determined that the shaft 10 has contacted the workpiece W. Alternatively, the predetermined load may be set as a load that can more reliably pick up the work W while suppressing damage to the work W. Further, the predetermined load can be changed according to the type of the work W.
　ここで、ひずみゲージ３７のひずみによる抵抗値変化は極めて微少であるため、ホイートストンブリッジ回路を利用して、電圧変化として取り出している。アクチュエータ１では、第一ひずみゲージ３７Ａに係るブリッジ回路の出力と、第二ひずみゲージ３７Ｂに係るブリッジ回路の出力とを並列に接続している。このように、両ブリッジ回路の出力を並列に接続することにより、以下のような温度の影響を取り除いた電圧変化を得ている。 Here, since the change in the resistance value due to the strain of the strain gauge 37 is extremely small, it is extracted as a voltage change using a Wheatstone bridge circuit. In the actuator 1, the output of the bridge circuit related to the first strain gauge 37A and the output of the bridge circuit related to the second strain gauge 37B are connected in parallel. As described above, by connecting the outputs of both bridge circuits in parallel, a voltage change that eliminates the influence of temperature as described below is obtained.
　ここで、温度の影響による連結アーム３６のひずみがないと仮定した場合には、第一ひずみゲージ３７Ａと第二ひずみゲージ３７Ｂとの夫々で検出される荷重は略同じになる。しかし、例えば、直動モータ３０の作動頻度が高く、且つ、回転モータ２０の作動頻度が低い場合には、直動モータ３０側の温度が回転モータ２０側の温度よりも高くなるため、第一アーム３６Ａと第二アーム３６Ｂとの間では、直動テーブル３３のＺ軸方向の膨張量が、回転モータ２０のＺ軸方向の膨張量よりも大きくなる。これにより、第一アーム３６Ａと第二アーム３６Ｂとが平行でなくなり、回転モータ２０側よりも直動モータ３０側の方が、第一アーム３６Ａと第二アーム３６Ｂとの距離が大きくなる。このときには、第一ひずみゲージ３７Ａは縮み、第二ひずみゲージ３７Ｂは伸びる。この場合、第一ひずみゲージ３７Ａの出力は、見かけ上、荷重の発生を示し、第二ひずみゲージ３７Ｂの出力は、見かけ上、負の荷重の発生を示す。このときには、第一アーム３６Ａ及び第二アーム３６Ｂに、直動テーブル３３のＺ軸方向の膨張量と回転モータ２０のＺ軸方向の膨張量との差によって生じる力が逆方向に等しくかかっているため、第一ひずみゲージ３７Ａの出力と、第二ひずみゲージ３７Ｂの出力とは、絶対値が等しく正負が異なっている。そのため、両ひずみゲージの出力を並列に接続することにより、温度の影響による出力を互いに打ち消すことができるため、別途温度に応じた補正を行う必要がない。そのため、簡易且つ高精度に荷重を検出することができる。このように、両ブリッジ回路の出力を並列に接続することにより、温度の影響を取り除いた電圧変化を得ることができ、この電圧変化はシャフト１０とワークＷとの間に発生する荷重に応じた値になる。 Here, assuming that there is no distortion of the connecting arm 36 due to the influence of temperature, the loads detected by the first strain gauge 37A and the second strain gauge 37B are substantially the same. However, for example, when the operation frequency of the linear motor 30 is high and the operation frequency of the rotary motor 20 is low, the temperature of the linear motor 30 is higher than the temperature of the rotary motor 20. Between the arm 36A and the second arm 36B, the amount of expansion of the translation table 33 in the Z-axis direction is larger than the amount of expansion of the rotary motor 20 in the Z-axis direction. As a result, the first arm 36A and the second arm 36B are not parallel, and the distance between the first arm 36A and the second arm 36B is larger on the side of the linear motor 30 than on the side of the rotary motor 20. At this time, the first strain gauge 37A contracts and the second strain gauge 37B expands. In this case, the output of the first strain gauge 37A apparently indicates the occurrence of a load, and the output of the second strain gauge 37B apparently indicates the occurrence of a negative load. At this time, the force generated by the difference between the amount of expansion of the translation table 33 in the Z-axis direction and the amount of expansion of the rotary motor 20 in the Z-axis direction is equally applied to the first arm 36A and the second arm 36B in the opposite direction. Therefore, the output of the first strain gauge 37A and the output of the second strain gauge 37B have the same absolute value and different signs. Therefore, by connecting the outputs of both strain gauges in parallel, the outputs due to the influence of temperature can be canceled each other, so that it is not necessary to separately perform correction according to temperature. Therefore, it is possible to easily and accurately detect the load. In this way, by connecting the outputs of both bridge circuits in parallel, it is possible to obtain a voltage change that eliminates the influence of temperature, and this voltage change corresponds to the load generated between the shaft 10 and the work W. Value.
　なお、本実施形態においては、ひずみゲージ３７を２つ設けているが、これに代えて、第一ひずみゲージ３７Ａまたは第二ひずみゲージ３７Ｂの何れか一方のみを設けていてもよい。この場合、ひずみゲージの検出値を周知の技術を用いて温度に応じて補正する。ひずみゲージ３７を１つ設けた場合であっても、ひずみゲージ３７の出力はシャフト１０とワークＷとの間に発生する荷重に応じた値になるため、ひずみゲージ３７の出力に基づいて、シャフト１０とワークＷとの間に発生する荷重を検出することができる。 In the present embodiment, two strain gauges 37 are provided, but only one of the first strain gauge 37A and the second strain gauge 37B may be provided instead. In this case, the detected value of the strain gauge is corrected according to the temperature using a known technique. Even when one strain gauge 37 is provided, the output of the strain gauge 37 is a value corresponding to the load generated between the shaft 10 and the workpiece W. It is possible to detect a load generated between the workpiece 10 and the work W.
　このように、連結アーム３６にひずみゲージ３７を設けることにより、ワークＷにシャフト１０が接したことを検出することができる。ここで、従来では、ワークＷにかかる力を検出することが困難であった。そのため、シャフト１０の先端部１０Ａに、衝撃を吸収するばね又は柔軟性の高い部材（例えばゴム）を取り付けていた。この場合、ワークＷにかかる力を精密に調整することが困難であった。また、シャフト１０がワークＷに当接したときの衝撃を低減するため、シャフト１０をワークＷに近付ける速度を低下させることもあった。この場合、タクトタイムが長くなってしまう。一方、本実施形態に係るアクチュエータ１によれば、ワークＷにシャフト１０が接したことをひずみゲージ３７により正確に検出することができるため、シャフト１０の速度を低下させずにワークＷにかかる力をより精密に調整することができる。 As described above, by providing the strain gauge 37 on the connecting arm 36, it is possible to detect that the shaft 10 is in contact with the workpiece W. Here, conventionally, it has been difficult to detect the force applied to the work W. Therefore, a spring or a highly flexible member (for example, rubber) that absorbs an impact is attached to the distal end portion 10A of the shaft 10. In this case, it was difficult to precisely adjust the force applied to the work W. Further, in order to reduce the impact when the shaft 10 comes into contact with the workpiece W, the speed at which the shaft 10 approaches the workpiece W may be reduced. In this case, the tact time becomes long. On the other hand, according to the actuator 1 according to the present embodiment, since the contact of the shaft 10 with the work W can be accurately detected by the strain gauge 37, the force applied to the work W without lowering the speed of the shaft 10 Can be adjusted more precisely.
　また、ワークＷに適切な力をかけることが可能となるため、ワークＷのピックアップをより確実に実行することができる。例えば、ワークＷをピックアップするときには、シャフト１０の先端部１０ＡにワークＷを押し付けた状態で中空部１１に負圧を発生させることにより、ワークＷをより確実にピックアップすることが可能となると共に、ワークＷを吸引したときにワークＷが勢いよくシャフト１０に衝突して破損することを抑制できる。一方、ワークＷを押し付ける荷重が大きすぎると、ワークＷが破損する虞がある。したがって、ワークＷにかかる荷重を検出しつつワークＷに適切な荷重をかけることにより、ワークＷの破損を抑制しつつ、より確実なワークＷのピックアップが可能となる。また、プレイス時においても、ワークＷに適切な荷重をかけることが求められる場合もある。例えば、ワークＷを他の部材に接着剤を用いて接着する場合には、接着の特性に応じた荷重をかける必要がある。このときにも、ワークＷにかかる荷重を適切に制御することにより、より確実な接着が可能となる。 (4) Since an appropriate force can be applied to the work W, the work W can be picked up more reliably. For example, when picking up the work W, the work W can be more reliably picked up by generating a negative pressure in the hollow portion 11 in a state where the work W is pressed against the distal end portion 10A of the shaft 10. When the work W is sucked, the work W can be prevented from violently colliding with the shaft 10 and being damaged. On the other hand, if the load pressing the work W is too large, the work W may be damaged. Therefore, by applying an appropriate load to the work W while detecting the load applied to the work W, it is possible to more reliably pick up the work W while suppressing damage to the work W. Further, even during the place, it may be required to apply an appropriate load to the work W. For example, when bonding the workpiece W to another member using an adhesive, it is necessary to apply a load according to the bonding characteristics. Also at this time, by appropriately controlling the load applied to the work W, more reliable bonding can be performed.
　また、従来では、シャフト１０の先端部１０Ａに負圧を発生させるために、シャフト１０全体を中空構造とし、シャフト１０の基端部にロータリジョイントを設けることがあった。このロータリジョイントを介して正圧及び負圧を供給することが可能である。しかし、ロータリジョイントをシャフト１０に接続すると、シャフト１０をＺ軸方向に移動または中心軸１００の回りに回転させるためにより大きなトルクが必要となるため、トルクがより大きなモータを採用する必要があった。また、可動部が多くなることにより、メンテナンスの頻度を高くする必要があった。 Conventionally, in order to generate a negative pressure at the distal end portion 10A of the shaft 10, the entire shaft 10 may have a hollow structure and a rotary joint may be provided at the base end portion of the shaft 10. Positive pressure and negative pressure can be supplied through this rotary joint. However, when the rotary joint is connected to the shaft 10, a larger torque is required to move the shaft 10 in the Z-axis direction or rotate around the central axis 100, so that it is necessary to employ a motor having a larger torque. . In addition, as the number of movable parts increases, it is necessary to increase the frequency of maintenance.
　一方、本実施形態に係るアクチュエータ１によれば、ロータリジョイントを使用せずとも、シャフト１０の中空部１１に負圧を発生させることができる。そうすると、ロータリジョイントを動かすために、トルクが大きい回転モータを選択しなくてもよくなる。メンテナンスの頻度を高くする必要もなくなる。 On the other hand, according to the actuator 1 according to the present embodiment, a negative pressure can be generated in the hollow portion 11 of the shaft 10 without using a rotary joint. Then, it is not necessary to select a rotary motor having a large torque in order to move the rotary joint. There is no need to increase the frequency of maintenance.
　また、ロータリジョイントを介して正圧及び負圧を供給する場合には、ロータリジョイントに接続されるチューブ等からシャフト１０が力を受けるため、この力がひずみゲージ３７の出力に含まれてしまう。そのため、ワークＷにかかる荷重を正確に検出することが困難となり得る。一方、本実施形態に係るアクチュエータ１のように、シャフトハウジング５０を介して正圧及び負圧を供給することにより、ロータリジョイントを用いる必要がなくなるので、ひずみゲージ３７により検出される荷重の精度をより高めることができる。 When the positive pressure and the negative pressure are supplied via the rotary joint, the shaft 10 receives a force from a tube or the like connected to the rotary joint, and this force is included in the output of the strain gauge 37. Therefore, it may be difficult to accurately detect the load applied to the work W. On the other hand, by supplying a positive pressure and a negative pressure via the shaft housing 50 as in the actuator 1 according to the present embodiment, it is not necessary to use a rotary joint, so that the accuracy of the load detected by the strain gauge 37 can be reduced. Can be more enhanced.
　なお、本実施形態に係るアクチュエータ１は、複数のアクチュエータ１をＹ軸方向に積層可能であるように形成されている。複数のアクチュエータ１は、隣り合うアクチュエータ１がＺ軸回りに１８０度回転した状態であっても積層可能である。シャフト１０は、ハウジング２のＸ軸方向の中心且つＹ軸方向の中心に設けられているため、アクチュエータ１をＺ軸回りに１８０度回転して配置してもシャフト１０の位置は変化しない。 The actuator 1 according to the present embodiment is formed so that a plurality of actuators 1 can be stacked in the Y-axis direction. The plurality of actuators 1 can be stacked even when adjacent actuators 1 are rotated by 180 degrees around the Z axis. Since the shaft 10 is provided at the center in the X-axis direction and the center in the Y-axis direction of the housing 2, the position of the shaft 10 does not change even if the actuator 1 is rotated 180 degrees around the Z axis.
＜第２実施形態＞
　第１実施形態においては、連結アーム３６にひずみゲージ３７を設けているが、シャフト１０とワークＷとの間に荷重が発生したときに、その荷重に応じてひずみが発生する部材であれば、他の部材にひずみゲージ３７を設けることもできる。 <Second embodiment>
In the first embodiment, the connecting arm 36 is provided with the strain gauge 37. However, when a load is generated between the shaft 10 and the workpiece W, any member that generates a strain in accordance with the load may be used. Another member may be provided with the strain gauge 37.
　図４及び図５は、回転モータ２０の出力軸２１を支持する２つの軸受２５に夫々ひずみゲージ３７を設けた場合の概略構成を示す図である。図４は、Ｚ軸方向上側に設けられる軸受２５Ａの周りの図であり、図５は、Ｚ軸方向下側に設けられる軸受２５Ｂの周りの図である。なお、両軸受を区別しない場合には、単に軸受２５という。軸受２５は、出力軸２１において回転子２３よりもＺ軸方向の上側（図４参照。）と下側（図５参照。）とに夫々設けられている。 FIGS. 4 and 5 are diagrams showing a schematic configuration in the case where strain gauges 37 are provided on two bearings 25 supporting the output shaft 21 of the rotary motor 20, respectively. FIG. 4 is a diagram around the bearing 25A provided on the upper side in the Z-axis direction, and FIG. 5 is a diagram around the bearing 25B provided on the lower side in the Z-axis direction. In the case where the two bearings are not distinguished, they are simply referred to as the bearing 25. The bearings 25 are provided on the output shaft 21 above (see FIG. 4) and below (see FIG. 5) the rotor 23 in the Z-axis direction, respectively.
　まず、図４を用いて回転子２３よりもＺ軸方向の上側に設けられるひずみゲージ３７について説明する。軸受２５Ａは、内周面が出力軸２１の外周面に嵌め込まれており、外周面が固定子２２に形成されている固定部２２０Ａの内周面に嵌め込まれている。固定部２２０Ａは、軸受２５ＡのＺ軸方向の上側に接するように、中心軸１００側に向かって突出する上部突出部２２１Ａを有している。上部突出部２２１ＡのＺ軸方向の上側の面に第一ひずみゲージ３７Ａが設けられている。 First, the strain gauge 37 provided above the rotor 23 in the Z-axis direction will be described with reference to FIG. The bearing 25 </ b> A has an inner peripheral surface fitted on the outer peripheral surface of the output shaft 21, and an outer peripheral surface fitted on an inner peripheral surface of a fixing portion 220 </ b> A formed on the stator 22. The fixing portion 220A has an upper protruding portion 221A protruding toward the center shaft 100 side so as to be in contact with an upper side of the bearing 25A in the Z-axis direction. A first strain gauge 37A is provided on an upper surface of the upper protrusion 221A in the Z-axis direction.
　次に、図５を用いて回転子２３よりもＺ軸方向の下側に設けられるひずみゲージ３７について説明する。軸受２５Ｂは、内周面が出力軸２１の外周面に嵌め込まれており、外周面が固定子２２に形成されている固定部２２０Ｂの内周面に嵌め込まれている。固定部２２０Ｂは、軸受２５ＢのＺ軸方向の上側に接するように、中心軸１００側に向かって突出する下部突出部２２１Ｂを有している。下部突出部２２１ＢのＺ軸方向の上側の面に第二ひずみゲージ３７Ｂが設けられている。 Next, the strain gauge 37 provided below the rotor 23 in the Z-axis direction will be described with reference to FIG. The bearing 25 </ b> B has an inner peripheral surface fitted on the outer peripheral surface of the output shaft 21, and an outer peripheral surface fitted on an inner peripheral surface of a fixing portion 220 </ b> B formed on the stator 22. The fixing portion 220B has a lower protruding portion 221B protruding toward the central shaft 100 so as to contact the upper side of the bearing 25B in the Z-axis direction. A second strain gauge 37B is provided on the upper surface of the lower protrusion 221B in the Z-axis direction.
　したがって、第一ひずみゲージ３７Ａ及び第二ひずみゲージ３７Ｂは、同じ方向を向く互いに平行な面であってシャフト１０の中心軸１００と直交する面に夫々設けられている。このような構成では、シャフト１０とワークＷとの間に発生した荷重により、上部突出部２２１Ａ及び下部突出部２２１Ｂにはひずみが生じる。このひずみは、シャフト１０とワークＷとの間に発生した荷重と相関関係にあるため、ひずみゲージ３７により、ひずみを検出することにより、シャフト１０とワークＷとの間に発生した荷重を検出することができる。また、第１実施形態と同様に、第一ひずみゲージ３７Ａと第二ひずみゲージ３７Ｂとは、温度の影響により逆方向のひずみを検出する。すなわち、上部突出部２２１Ａと下部突出部２２１Ｂとの間の固定子２２の膨張量と出力軸２１の膨張量とに差がある場合には、上部突出部２２１Ａ及び下部突出部２２１Ｂに逆方向で同じ大きさの力がかかる。このときには、第一ひずみゲージ３７Ａの出力と、第二ひずみゲージ３７Ｂの出力とは、絶対値が等しく正負が異なっている。そのため、両ひずみゲージの出力を並列に接続することにより、温度の影響による出力を互いに打ち消すことができるため、別途温度に応じた補正を行う必要がない。したがって、簡易且つ高精度に、シャフト１０及びワークＷに加わる荷重を検出することができる。 Therefore, the first strain gauge 37A and the second strain gauge 37B are provided on surfaces parallel to each other in the same direction and orthogonal to the central axis 100 of the shaft 10. In such a configuration, the load generated between the shaft 10 and the work W causes distortion in the upper protrusion 221A and the lower protrusion 221B. Since this strain is correlated with the load generated between the shaft 10 and the work W, the strain gauge 37 detects the strain to detect the load generated between the shaft 10 and the work W. be able to. Further, similarly to the first embodiment, the first strain gauge 37A and the second strain gauge 37B detect strains in opposite directions under the influence of temperature. That is, when there is a difference between the amount of expansion of the stator 22 and the amount of expansion of the output shaft 21 between the upper protruding portion 221A and the lower protruding portion 221B, the upper protruding portion 221A and the lower protruding portion 221B are turned in opposite directions. The same amount of force is applied. At this time, the output of the first strain gauge 37A and the output of the second strain gauge 37B have the same absolute value and different positive and negative. Therefore, by connecting the outputs of both strain gauges in parallel, the outputs due to the influence of temperature can be canceled each other, so that it is not necessary to separately perform correction according to temperature. Therefore, the load applied to the shaft 10 and the work W can be easily and accurately detected.
＜その他の実施形態＞
　第１実施形態においては、連結アーム３６にひずみゲージ３７を設けているが、これに代えて、連結アーム３５にひずみゲージ３７を設けることもできる。すなわち、２つの連結アーム３５の夫々において、Ｚ軸方向の上側を向く面にひずみゲージ３７を夫々設けることもできる。また、２つの連結アーム３５の夫々において、Ｚ軸方向の下側を向く面にひずみゲージ３７を夫々設けることもできる。連結アーム３６のＺ軸方向の上側を向く面または下側を向く面にも、シャフト１０とワークＷとの間に発生する荷重の大きさに応じたひずみが発生する。したがって、このひずみを検出することにより、荷重を検出することができる。また、連結アーム３５も、Ｚ軸方向にずらして２つ配置されており、夫々の中心軸が互いに平行であり、且つ、夫々の中心軸がシャフト１０の中心軸１００と直交している。そのため、第１実施形態で説明したように、熱膨張によって連結アーム３５にひずみが生じた場合であっても、２つのひずみゲージの出力を並列に接続することにより、熱膨張によるひずみの影響を打ち消すことができる。したがって、簡易且つ高精度に、シャフト１０及びワークＷに加わる荷重を検出することができる。 <Other embodiments>
In the first embodiment, the connection arm 36 is provided with the strain gauge 37. Alternatively, the connection arm 35 may be provided with the strain gauge 37. That is, in each of the two connecting arms 35, a strain gauge 37 can be provided on a surface facing upward in the Z-axis direction. In each of the two connecting arms 35, a strain gauge 37 may be provided on a surface facing downward in the Z-axis direction. A strain corresponding to the magnitude of the load generated between the shaft 10 and the work W is also generated on the surface of the connection arm 36 facing upward or downward in the Z-axis direction. Therefore, the load can be detected by detecting the strain. The two connecting arms 35 are also displaced in the Z-axis direction, and their respective central axes are parallel to each other, and their respective central axes are orthogonal to the central axis 100 of the shaft 10. Therefore, as described in the first embodiment, even when a strain occurs in the connection arm 35 due to thermal expansion, the influence of the strain due to thermal expansion can be reduced by connecting the outputs of the two strain gauges in parallel. Can be countered. Therefore, the load applied to the shaft 10 and the work W can be easily and accurately detected.
１・・・アクチュエータ、２・・・ハウジング、１０・・・シャフト、１０Ａ・・・先端部、１１・・・中空部、２０・・・回転モータ、２２・・・固定子、２３・・・回転子、３０・・・直動モータ、３１・・・固定子、３２・・・可動子、３６・・・連結アーム、３７・・・ひずみゲージ、５０・・・シャフトハウジング、６０・・・エア制御機構 DESCRIPTION OF SYMBOLS 1 ... Actuator, 2 ... Housing, 10 ... Shaft, 10A ... Tip part, 11 ... Hollow part, 20 ... Rotation motor, 22 ... Stator, 23 ... Rotor, 30 ... linear motor, 31 ... stator, 32 ... mover, 36 ... connecting arm, 37 ... strain gauge, 50 ... shaft housing, 60 ... Air control mechanism

Claims (5)

  1.   シャフトと、
    　前記シャフトを回転可能に支持する支持部と、
    　固定子及び可動子を有する直動モータであって、前記直動モータの前記固定子に対して前記可動子が前記シャフトの中心軸と平行に移動することにより、前記支持部及び前記シャフトを前記シャフトの前記中心軸の方向に移動させる直動モータと、
    　前記直動モータの前記可動子と前記支持部とを接続する部材の少なくとも一部である接続部材と、
    　を備えるアクチュエータにおいて前記シャフトにかかる力を検出する荷重検出器であって、
    　前記接続部材に設けられ前記接続部材のひずみを検出するひずみゲージを備える、荷重検出器。     Shaft and
    A support portion rotatably supporting the shaft,
    A linear motor having a stator and a movable element, wherein the movable element moves parallel to a central axis of the shaft with respect to the stator of the linear motor, thereby moving the support portion and the shaft. A linear motor that moves in the direction of the central axis of the shaft;
    A connection member that is at least a part of a member that connects the mover and the support portion of the linear motor,
    A load detector that detects a force applied to the shaft in an actuator including:
    A load detector, comprising: a strain gauge provided on the connection member to detect a strain of the connection member.
  2.   前記接続部材は、前記シャフトの前記中心軸の方向にずらして設けられる第一部材及び第二部材を有し、
    　前記ひずみゲージは、前記第一部材及び前記第二部材に夫々に設けられる同じ方向を向く互いに平行な面であって前記シャフトの前記中心軸と直交する面に夫々設けられる、
    　請求項１に記載の荷重検出器。     The connection member has a first member and a second member provided to be shifted in a direction of the central axis of the shaft,
    The strain gauge is provided on the first member and the second member, respectively, are provided on surfaces parallel to each other and facing the same direction and orthogonal to the central axis of the shaft,
    The load detector according to claim 1.
  3.   前記第一部材に設けられるひずみゲージと、前記第二部材に設けられるひずみゲージとは、夫々が異なるホイートストンブリッジ回路に組み込まれ、両ホイートストンブリッジ回路の出力が並列に接続される、
    　請求項２に記載の荷重検出器。     The strain gauge provided on the first member and the strain gauge provided on the second member are each incorporated into a different Wheatstone bridge circuit, and the outputs of both Wheatstone bridge circuits are connected in parallel.
    The load detector according to claim 2.
  4. 　前記支持部が、固定子及び回転子を有する回転モータであって、前記回転モータの前記固定子に対して、前記シャフトに接続される前記回転子が回転することにより、前記シャフトを前記シャフトの前記中心軸の回りに回転させる回転モータであり、
      前記第一部材及び前記第二部材は、前記直動モータの前記可動子と前記回転モータの前記固定子とを接続する２つのアームであって、前記２つのアームの夫々の中心軸が前記シャフトの前記中心軸の方向と直交し、且つ、前記２つのアームの前記中心軸が互いに平行になる２つのアームである、
    　請求項２または３に記載の荷重検出器。     The support portion is a rotary motor having a stator and a rotor, and the rotor connected to the shaft rotates with respect to the stator of the rotary motor, thereby causing the shaft to rotate. A rotation motor that rotates around the central axis,
    The first member and the second member are two arms that connect the mover of the linear motion motor and the stator of the rotary motor, and each of the two arms has a central axis of the shaft. The two arms are orthogonal to the direction of the central axis, and the central axes of the two arms are parallel to each other.
    The load detector according to claim 2.
  5. 　前記支持部が、固定子及び回転子を有する回転モータであって、前記回転モータの前記固定子に対して、前記シャフトに接続される前記回転子が回転することにより、前記シャフトを前記シャフトの前記中心軸の回りに回転させる回転モータであり、
      前記接続部材は、前記直動モータの前記可動子と前記回転モータの前記固定子とを接続するアームであって、前記アームの中心軸が前記シャフトの前記中心軸の方向と直交するアームである、
    　請求項１に記載の荷重検出器。     The support portion is a rotary motor having a stator and a rotor, and the rotor connected to the shaft rotates with respect to the stator of the rotary motor, thereby causing the shaft to rotate. A rotation motor that rotates around the central axis,
    The connection member is an arm that connects the mover of the linear motion motor and the stator of the rotary motor, and the center axis of the arm is orthogonal to the direction of the center axis of the shaft. ,
    The load detector according to claim 1.
PCT/JP2019/030261 2018-08-01 2019-08-01 Load detector for actuator WO2020027273A1 (en)

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