WO2020027273A1 - アクチュエータの荷重検出器 - Google Patents

アクチュエータの荷重検出器 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
English (en)
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/ja

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    • 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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  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Manipulator (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
  • Linear Motors (AREA)
PCT/JP2019/030261 2018-08-01 2019-08-01 アクチュエータの荷重検出器 WO2020027273A1 (ja)

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US11698309B2 (en) 2020-03-05 2023-07-11 Delta Electronics, Inc. Linear actuator

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JPS60191785A (ja) * 1984-03-13 1985-09-30 富士機械製造株式会社 電子部品吸着ヘツド
JPS6444821A (en) * 1987-08-13 1989-02-17 Yamato Scale Co Ltd Thin-type weighing machine
WO2001078482A1 (de) * 2000-04-05 2001-10-18 Siemens Production And Logistics Systems Ag Bestückvorrichtung mit einer einrichtung zum messen der aufsetzkraft
JP2010003728A (ja) * 2008-06-18 2010-01-07 Juki Corp 表面実装装置
JP2010034095A (ja) * 2008-07-24 2010-02-12 Juki Corp 電子部品実装装置

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JPS60191786A (ja) * 1984-03-08 1985-09-30 三星精密工業株式会社 産業用ロボツトに適するグリツパ−
JP3762246B2 (ja) * 2001-04-04 2006-04-05 Ｔｄｋ株式会社 処理装置
JP2018072185A (ja) * 2016-10-31 2018-05-10 セイコーエプソン株式会社 押圧装置、電子部品搬送装置、電子部品検査装置およびロボット

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Publication number Priority date Publication date Assignee Title
JPS60191785A (ja) * 1984-03-13 1985-09-30 富士機械製造株式会社 電子部品吸着ヘツド
JPS6444821A (en) * 1987-08-13 1989-02-17 Yamato Scale Co Ltd Thin-type weighing machine
WO2001078482A1 (de) * 2000-04-05 2001-10-18 Siemens Production And Logistics Systems Ag Bestückvorrichtung mit einer einrichtung zum messen der aufsetzkraft
JP2010003728A (ja) * 2008-06-18 2010-01-07 Juki Corp 表面実装装置
JP2010034095A (ja) * 2008-07-24 2010-02-12 Juki Corp 電子部品実装装置

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