JP6032762B2 - Torque detector integrated motor system - Google Patents

Description

  The present invention relates to a torque detection unit integrated motor system capable of detecting torque of an output shaft.

  Conventionally, as shown in FIG. 5, as a means for detecting a rotational torque while transmitting the power of the motor unit 3 to a load device and performing a torque control circuit, a speed reducer 16 is connected to the output shaft of the motor unit 3 to rotate the motor. At the same time, the torque is increased and the torque detector 4 that can measure the torque is connected via a shaft coupling such as the coupling 17, and the rotary shaft 5 that is the output of the torque detector 4 is connected to the load device. Things were common. The encoder unit 204 has an encoder connector 204, the motor unit 3 has a motor connector, and the torque detection unit 4 has a sensor connector 6. There are independent connectors for handling control circuit signals. It was complicated. With this configuration, each unit is independent, and maintenance such as replacement of parts is advantageous. However, since the length in the axial direction becomes long, it is difficult to use for a robot or the like, and there is a limited application.

  As an improvement on this, an invention is disclosed in which a motor, a speed reducer, and a torque detector are configured in an integral structure.

Patent Document 1 discloses an actuator in which a flex spline of a wave gear reducer is disposed in a gap between a stator and a rotor of a motor, and a serial converter that combines an output encoder and a torque detection wiring of the reducer together. Is converted to a serial signal and connected to an external controller.

Japanese Patent No. 4581543

  However, in Patent Document 1, the detection signals of the encoder and the torque sensor are wired to the serial converter by a connector and a cable, respectively, and a plurality of these wirings are individually performed, so that the assembly is complicated. there were.

  In addition, if a thermometer is directly attached to the motor unit, a separate wiring cable is required to detect abnormal heat generation in the motor unit. Therefore, it is necessary to detect the temperature of the control circuit unit of the external control unit that drives the motor or to wind the motor. The line resistance value is measured and estimated from this. In any case, since the actual heat generation of the motor is not measured, it is necessary to make an arithmetic expression unique to each motor.

  An object of the present invention is to simplify a plurality of wirings and realize a torque detection unit integrated motor system capable of directly detecting the temperature of a motor unit.

A torque detection unit integrated motor system according to the present invention includes a motor unit,
An encoder unit connected to the motor unit on the opposite side of the motor unit to detect the rotation angle of the motor;
A torque detector connected to the load side of the motor unit for detecting the rotational torque of the output shaft connected to the load;
A control circuit integrated substrate provided along the outside of the housing of the motor unit and integrated with at least a part of a control circuit for controlling each of the encoder unit and the torque detection unit;
A connector for electrical connection between the control circuit integrated substrate and the external controller;
On the control circuit integrated substrate, it is provided in the vicinity of the motor unit facing the outside of the casing, and is configured with a temperature detection unit that detects the temperature of the motor unit.

  It is preferable that the encoder unit and the torque detection unit each have a circuit board provided with at least a part of a control circuit that performs the respective controls.

1 is an external perspective view of a torque detection unit-integrated motor system showing a first embodiment of the present invention. Structural perspective view of the torque detection unit integrated motor system showing the first embodiment of the present invention Cross-sectional view of the structure of the motor system integrated with a torque detector showing the first embodiment of the present invention Structural perspective view of a torque detection unit integrated motor system showing a second embodiment of the present invention A diagram showing the configuration of a conventional torque detector, reducer, and motor

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 and 2 are external perspective views of the torque detection unit-integrated motor system according to the first embodiment of the present invention. In FIG. 2, a part of the exterior portion shown in FIG. 1 is omitted. The internal structure is shown.

  In FIG. 1, the torque detection unit-integrated motor system 1 includes an encoder unit 2, a motor unit 3, and a torque detection unit 4. It has become. The encoder unit 2 is on the opposite load side of the motor unit 3, and the torque detection unit 4 is on the load side of the motor unit 3, and is arranged side by side in the axial direction. The encoder unit 2, the motor unit 3, and the torque detection unit 4 each have a casing serving as an exterior, and the encoder casing 201, the motor casing 301, and the torque detection unit casing 401 are respectively connected by bolts. In this embodiment, the torque detector 4 is housed in the torque detector housing 401 integrally with the wave gear reducer.

  Further, a motor connector 302 and a sensor connector 6 are provided in the motor casing 301 and the torque detecting section casing 401 for electrical connection between the motor section 3 and the torque detecting section 4 and an external controller (not shown), respectively. .

  The substrate casing frame 7a and the substrate casing lid 7b are provided in the axial direction of the encoder unit 2, the motor unit 3, and the torque detecting unit 4, and the encoder unit 2 and the inside of the torque detecting unit 4 are opened. Although connected with each other, the motor unit 3 is isolated without any opening. Accordingly, the substrate casing frame 7a and the substrate casing lid 7b are attached to a part of the encoder unit 2 and the torque detection unit 4 that are extended, and are substantially the same casing of the encoder unit 2 and the torque detection unit 4. It has a structure.

  Next, an embodiment according to the present invention will be described with reference to FIG. In FIG. 2, the substrate casing frame 7a, the substrate casing lid 7b, and the encoder casing 201 in FIG. 1 are omitted.

  The encoder unit 2 has an encoder control circuit board 8c, and the encoder plate 203 reads the rotation angle of the motor and converts it into an electrical signal. The output from the encoder control circuit board 8c is taken out by the connector 14 and the cable 13 provided on the encoder control circuit board 8c.

  A control circuit integrated substrate 8a is attached to the substrate housing frame 7a and the substrate housing lid 7b so as to be surrounded by the substrate housing frame 7a. The control circuit integrated substrate 8a is provided to extend in the axial direction from the encoder unit 2 through the motor unit 3 to the torque detection unit 4, and the area of the motor unit 3 is positioned outside the motor housing 301 in the axial direction. It has become.

  Further, the torque detection control circuit board 8b is located in the region of the torque detector 4 so as to face the control circuit integrated board 8a in parallel. The control circuit integrated board 8a and the torque detection control circuit board 8b are connected by the inter-board connector 15. Electrically connected. A connector 10 is provided on the control circuit integrated substrate 8a, and is connected to the sensor connector 6 by a cable 11 so as to be connected to an external controller. Details of the control circuit integrated board 8a and the torque detection control circuit board 8b will be described later.

  Next, details of each component will be described with reference to FIG. FIG. 3 is a structural sectional view of the torque detection unit integrated motor system showing the first embodiment of the present invention, and shows details of the encoder unit 2, the motor unit 3, and the torque detection unit 4.

  In the motor unit 3, a motor shaft 305 is rotatably supported by bearings 306 at two locations in the rotation axis direction, and a rotor 304 is attached to the motor shaft 305. In this embodiment, the motor unit 3 is a surface magnet type permanent magnet synchronous motor, and the permanent magnet of the rotor 304 is bonded so as to surround the motor shaft 305. A stator 303 made of a winding is provided around the rotor 304 and its wiring is electrically connected to the motor connector 302 (see FIG. 2). Further, the outer periphery of the stator 303 is surrounded by a motor casing 301, and an aluminum alloy is used in consideration of shielding of electromagnetic noise and securing of rigidity and weight reduction.

  The encoder unit 2 is mechanically connected to the non-load side of the motor shaft 305 for detecting the rotational position of the motor shaft 305. In this embodiment, an optical encoder is used, and an encoder plate 203 that is directly connected to the motor shaft 305 and has a reflection pattern is attached. An encoder control circuit board 8c having a light-emitting / receiving element that emits light to the encoder plate 203 and receives reflected light to detect the position is disposed around the encoder plate 203 with a predetermined distance from the encoder plate 203. . Furthermore, the encoder control circuit board 8c is covered with an encoder housing 201. (See Figure 1)

  A wave gear reducer is mechanically connected to the load side of the motor shaft 305. The wave gear reducer includes a flex spline 422 having a thin cup shape and gear teeth provided on the outer periphery of the opening, and a circular spline having gear teeth on the inner peripheral surface corresponding to the outer peripheral gear teeth of the flex spline 422. 421 and a wave generator 420 coupled to the motor shaft 305 located at the opened inner periphery of the flex spline 422.

  The wave generator 420 is a part in which a thin ball bearing is combined on the outer periphery of an elliptical cam. The inner ring of the bearing is fixed to the cam, and the outer ring is elastically deformed via the ball. The flex spline 422 is a thin cup-shaped metal elastic body, and the bottom of the thin cup of the flex spline 422 is called a diaphragm and functions as a reduction gear output. The circular spline 421 is a rigid ring-shaped part, and has an internal tooth structure having two more teeth than the flex spline 422.

  The flex spline 422 is bent into an elliptical shape by the wave generator 420, and the teeth of the circular spline 421 mesh with each other at the major axis of the ellipse, and the teeth do not mesh at the minor axis. When the circular spline 421 is fixed and the wave generator 420 is rotated clockwise, the flex spline 422 is elastically deformed, and the meshing position of the teeth with the circular spline 421 sequentially moves. When the wave generator 420 makes one rotation, the flex spline 422 moves counterclockwise by two teeth difference. Therefore, the diaphragm of the flex spline 422 of the wave gear reducer serves as an output unit, and the speed is reduced by the reduction ratio of the wave gear reducer.

  The output shaft 5 is connected to the diaphragm portion of the flex spline 422 of the wave gear reducer, that is, the reducer output portion by bolts. The output shaft 5 is rotatably provided by a bearing 416 and a bearing 415 that are deep groove ball bearings, and the outer ring side of the bearing 416 and the bearing 415 is fixed by a cover that also serves as an exterior part.

  The output shaft 5 is rotatably supported, and transmits the power decelerated by the speed reducer and includes a strain generating portion 5a for detecting rotational torque. The strain generating portion 5a has a small outer diameter at the central portion in the axial direction of the output shaft 5, and is not deformed with strength in the axial direction of the output shaft 5, but deforms in the torsional direction. A strain gauge (not shown) is affixed to the surface, and a torsion occurring in the strain generating portion 5a is detected from a change in the resistance value of the strain gauge resistor to detect a rotational torque. The shape of the strain generating portion 5a is not limited to a cylindrical shape, and an optimal one is selected depending on the amount of rotational torque to be measured. On the load side of the output shaft 5, it is mechanically connected to a load device (not shown), and rotational torque is detected while rotating together with the load device.

  On the other hand, the primary side core 410 and the primary side core 411, the secondary side core 413, and the secondary side coil 412 form a rotary transformer structure that supplies power without contact. The output shaft 5 has a rotation side substrate 418 that rotates together with the output shaft 5, and the rotation side substrate 418 is equipped with a Wheatstone bridge circuit configured to include a strain gauge attached to the cylindrical surface of the strain generating portion 5a. The power is supplied to the circuit in a non-contact manner.

  Hereinafter, the flow of electric power and electric signals in the control circuit of the torque detector 4 will be described. Electric power is supplied to the torque detection control circuit board 8b from the external controller via the control circuit integrated board 8a, and this direct current is converted into alternating current and provided on the output shaft 5 to rotate together. A switching circuit is provided for supplying power to the power source.

  The primary core 410 is a ferrite having a U-shaped cross section with protrusions at both ends, and is attached to the torque detection control circuit board 8b via the primary core holder 417. A primary core 411 formed by winding a copper wire is provided between both protrusions of the primary core 410. The primary core 411 is electrically connected to the torque detection control circuit board 8b, and power is supplied from a switching circuit in the torque detection control circuit board 8b.

  On the other hand, the power receiving side of the transformer, that is, the secondary side is configured on the output shaft 5 side so as to face the primary side core 410 and the primary side core 411 at a predetermined interval. That is, a cylindrical secondary core base 419 is fixed on the cylindrical outer peripheral surface of the output shaft 5, and a secondary core 413 is provided on the outer peripheral cylindrical surface, and a copper wire is provided on the outer periphery of the secondary core 413. A secondary coil 412 is provided. The secondary core 413 is wound and bonded to the outer peripheral cylindrical surface of the secondary core base 419 with a strip-shaped ferrite sheet. Further, the electric wire drawn out from the secondary coil 412 is electrically connected to the rotation side substrate 418.

  Accordingly, electric power is supplied from the external controller to the control circuit integrated board 8a and the torque detection control circuit board 8b, and the primary core 411 is energized with the current converted into alternating current by the switching circuit on the torque detection control circuit board 8b. Then, an alternating magnetic field is generated, and this alternating magnetic field passes through the secondary side core 413 on the output shaft 5 side, so that a current is induced in the secondary side coil 412. The induced current is supplied to a strain gauge that forms a Wheatstone bridge circuit through a rectification circuit and a stabilization circuit in the rotation side substrate 418. The strain gauge is electrically connected to the rotation side substrate 418.

  The rotation-side substrate 418 is attached to the output shaft 5 and has an annular shape, and the arrangement position of the electronic components is considered on the substrate so as to maintain a balance during rotation.

  In actual torque detection, when torque is applied to the output shaft 5, the strain generating portion 5a of the output shaft 5 is distorted according to the magnitude of the torque, and the magnitude of this distortion changes the resistance value of the resistor of the strain gauge. Is detected as the size of. The detection is performed by a control circuit provided in the rotation side substrate 418, and the detected analog signal is digitized and modulated by A / D conversion.

  This digitized signal is transmitted by the LED for infrared communication provided on the rotation side substrate 418, and is received by the light receiving element provided on the torque detection control circuit board 8b, and corresponds to the torque value. A digital signal can be obtained. A demodulating circuit is provided on both or either of the control circuit integrated board 8a and the torque detection control circuit board 8b so that a voltage signal corresponding to the detected torque value can be output. The output voltage signal is sent to the control circuit integrated board 8a via the board-to-board connector 15 and connected to the external controller via the connector 10, the cable 11 and the sensor connector 6, and used for the motor control circuit. The

  The control circuit integrated board 8a includes a circuit that processes exchange of signals with the encoder control circuit board 8c and the torque detection control circuit board 8b, and a circuit that supplies power to each of them. On the motor unit 3 side of the control circuit integrated substrate 8a, a temperature detection unit 20 is provided so as to be in contact with the substrate housing frame 7b. Heat generated in the motor unit 3 is conducted to the temperature detection unit 20 through the motor housing 301 and the substrate housing frame 7b, and the temperature of the motor unit 3 can be detected. Since the motor casing 301 and the substrate casing frame 7b are both made of an aluminum alloy, the heat conduction is good and a temperature close to the actual motor coil temperature can be measured.

  The signals from the encoder control circuit board 8c, the torque detection control circuit board 8b, and the temperature detection unit 20 are all serial signals. Therefore, a plurality of serial signals are collected by SerDes provided on the control circuit integrated board 8a so that the parallel interface between the torque detection unit integrated motor system 1 and the external controller can be serially connected. Of course, a parallel I / F may be used. However, since the number of wires increases, the selection can be made as appropriate according to the required specifications of the torque detection unit-integrated motor system.

  Furthermore, the control circuit integrated substrate 8a is disposed outside the motor housing 301, is surrounded by the substrate housing frame 7a, and is covered by the substrate housing 7b. Therefore, at the time of assembly, first, the torque detection control circuit board 8b is fixed to the torque detection unit housing 401, and the control circuit integrated board 8a is connected to the torque detection control circuit board 8b via the board-to-board connector 15, and then the encoder control circuit board is pre- The connection is completed by inserting the cable 13 connected to 8c into the connector 12, and similarly inserting the cable 11 previously connected to the sensor connector 6 into the connector 10.

  FIG. 4 is a structural perspective view of a motor system integrated with a torque detector showing a second embodiment of the present invention, and shows the internal structure with a part of the exterior part omitted as in FIG. In the second embodiment, the control circuit integrated board 8a and the encoder control circuit board 8c are integrated boards. That is, the control circuit integrated substrate 8a and the encoder control circuit substrate 8c are rigid substrates, and the wiring portion 19 connected to the wiring layer is a flexible base substrate, and a so-called rigid flexible substrate is used. According to this, the mounting process of the electronic component of each board | substrate is only one time, the insertion of a connector is unnecessary, and manufacture of a cable harness is also unnecessary, and it can reduce cost in comprehensive view. The same configuration is possible for the control circuit integrated board 8a and the torque detection control circuit board 8b.

  As described above, the connection of the sensing system signals to the external controller is collected on the control circuit integrated board 8a and concentrated on the sensor connector 6, thereby simplifying the wiring. In particular, by providing the sensor connector 6 on the torque detection unit housing 401 side, the axial length of the torque detection unit integrated motor system 1 can be shortened, and the connector 10 and the sensor connector 6 wiring on the control circuit board 8 can be connected. The cable length of the cable 11 to be performed can be shortened.

  Further, since the temperature detector 20 is provided on the control circuit integrated substrate 8a and the temperature of the motor unit 3 can be directly detected, a conversion calculation for estimating the temperature of the motor unit from the temperature detection of the control circuit unit of the external controller is unnecessary. Become. Since the temperature is directly detected, there is an advantage that it is not affected by a difference due to an environmental temperature where the torque detection unit-integrated motor system 1 is placed, an attached device, or the like.

  Further, the control circuit of the torque detection unit, the encoder control circuit, and the control circuit of the temperature detection unit 20 are integrated on one substrate, that is, the control circuit integrated substrate 8a to reduce the wiring, and the motor unit 3 which is a noise source. In a portion close to, the motor casing 301 is placed outside the shielded shield. Therefore, the control circuit board 8, the encoder control circuit board 202, and the cable 13 are configured not to be affected by noise from the motor unit 3.

In this embodiment, the torque detection control circuit board 8b has a part of the torque control circuit, the encoder control circuit board 8c has an encoder control circuit, and the control circuit integrated board 8a has a part of the torque control circuit and the temperature detection unit 20. The control circuit and the external controller have an I / F circuit, that is, SerDes. In addition, the encoder control circuit board 8c is configured to have a minimum configuration of a detection element and its peripheral circuit, and the main part of the encoder control circuit is mounted on the control circuit integrated board 8a. Various modifications can be made without departing from the spirit and scope of the present invention, such as mounting the main part of the torque detection control circuit on the control circuit integrated substrate 8a with a minimum configuration of a transformer and its peripheral circuits.

  As an application example of the present invention, the present invention can be applied to a robot or the like as an actuator that generates power while controlling a torque.

DESCRIPTION OF SYMBOLS 1 Torque detection part integrated motor system 2 Encoder part 201 Encoder part housing | casing 202 Substrate base 203 Encoder board 204 Encoder connector 3 Motor part 301 Motor cover 302 Motor connector 303 Stator 304 Rotor 305 Motor shaft 306 Bearing 4 Torque detection part 401 Torque detector housing 410 Primary side core 411 Primary side coil 412 Secondary side coil 413 Secondary side core 414 Secondary side core holder 415 Bearing 416 Bearing 417 Primary side core holder 418 Rotation side substrate 419 Secondary side core base 420 Wave generator 421 Circular spline 422 Flex spline 5 Output shaft 5a Strain portion 6 Sensor connector 7a Substrate casing lid 7b Substrate casing frame 8a Control circuit integrated substrate 8b Torque detection The control circuit board 8c encoder control circuit board 10 Connector 11 cable 12 connector 13 cable 14 connector 15 board between the connectors 16 reducer 17 coupling 18 fixed base 19 wiring unit 20 temperature detector

Claims (2)

A motor section;
An encoder unit connected to the motor unit on the non-load side of the motor unit to detect a rotation angle of the motor;
A torque detector connected to the load side of the motor unit for detecting the rotational torque of the output shaft connected to the load;
A control circuit integrated board provided along the outside of the casing of the motor unit and integrated with at least a part of a control circuit for controlling each of the encoder unit and the torque detection unit;
A connector for electrical connection between the control circuit integrated substrate and an external controller;
On the control circuit integrated substrate, provided in the vicinity facing the outside of the housing of the motor unit, a temperature detection unit for detecting the temperature of the motor unit,
A motor system integrated with a torque detector.
2. The torque detection unit-integrated motor system according to claim 1, wherein the encoder unit and the torque detection unit each include a circuit board including at least a part of a control circuit that performs control of each of the encoder unit and the torque detection unit.