drive device and robot equipped with a drive device

Abstract

This drive device comprises: an electric motor unit, which includes an electric motor, and an amplifier that supplies power to the electric motor. The amplifier comprises a number of electrical components mounted on a substrate. The amplifier is mounted coaxially to an end section of the electric motor unit in the direction of the electric motor's rotating shaft. The amplifier is designed so that it can be detached from the electric motor unit by operation of a worker.

Description

Technical area

[0001] The present invention relates to a drive device and a robot comprising the drive device. Related prior art

[0002] A drive device that transmits the rotational force of an electric motor to another element is known from the prior art. The drive device may include an electric motor, a deceleration device that amplifies the rotational force of the electric motor, a brake, and the like. A current generated based on a predetermined command is supplied to the electric motor of the drive device. The current supplied to the electric motor is generated by an amplifier. The amplifier is housed, for example, in a control device separate from the drive device. The control device is capable of supplying power to the electric motor of the drive device via a cable. Alternatively, a drive device is known that includes an amplifier in addition to the electric motor and the deceleration device (e.g., Japanese Unexamined Patent Publication No. 2010-41747 A).

[0003] The drive device may be arranged in a robot device, while the robot device may be provided with a robot that includes a joint at which the orientation of a component, e.g., an arm, changes. The robot device can perform operations while changing the position and orientation of the work tools by driving the components of the robot. If the robot includes the joint, the drive device for moving the components is arranged in the joint. The drive device may be arranged for each joint (e.g., Japanese Unexamined Patent Publication No. 2019-84607 A). Citation listPatent literature PTL 1: Unexamined Japanese Patent Publication No. 2010-41747 A PTL 2: Unexamined Japanese Patent Publication No. 2019-84607 A Summary of the inventionTechnical problem

[0004] The drive device can be arranged in each machine. Furthermore, the booster can be arranged for each electric motor. In this case, the booster fails more frequently than the deceleration device, the electric motor, and the brake. Preferably, the drive device has a structure that allows the booster to be easily replaced when it fails. In other words, it is preferable to use a structure that allows the booster to be easily removed from the drive device. However, with the known drive devices, it is difficult to remove only the booster from the drive device attached to the machine.

[0005] For example, the drive device may be equipped with a secondary encoder that detects the rotational position of the deceleration device's output shaft in addition to a primary encoder that detects the rotational position of the electric motor. The secondary encoder is connected to an element related to the deceleration device's output. For example, the secondary encoder is arranged at the outermost portion of the drive device to detect the rotational position of an element that rotates together with the deceleration device's output shaft. The amplifier, on the other hand, is arranged inside the drive device. To remove the amplifier, the drive device must be disassembled after the entire drive device has been detached from the machine. Therefore, it is not possible to remove only the amplifier from the drive device attached to the machine. Solution to the problem

[0006] A drive device according to one aspect of the present disclosure includes an electric motor unit including an electric motor, and an electric motor control unit configured to supply power to the electric motor. The electric motor unit includes at least one device selected from the group consisting of a deceleration device, a brake, and a rotational position detecting device. The electric motor control unit includes a substrate and a plurality of electrical components mounted on the substrate. The electric motor control unit is coaxially mounted to an end portion of the electric motor in the direction of a rotational axis of the electric motor unit. The electric motor control unit is configured to be detachable from the electric motor unit by operation by an operator.

[0007] A robot of the present disclosure includes the drive device described above and a joint configured to rotate one component of the robot relative to another component of the robot. The drive device is arranged on the joint. Advantageous effects of the invention

[0008] According to an aspect of the present disclosure, it is possible to provide a driving device and a robot including the driving device, with which an electric motor control unit can be easily detached from a driving device. Brief description of the drawings [ Fig. 1] Fig. 1 is a perspective view of a robot according to an embodiment; [ Fig. 2] Fig. 2 is a schematic sectional view of a drive device of the embodiment; [ Fig. 3] Fig. 3 is an electrical circuit diagram of an amplifier according to the embodiment; [ Fig. 4] Fig. 4 is a schematic perspective view of the amplifier; [ Fig. 5] Fig. 5 is a schematic plan view of the amplifier; [ Fig. 6] Fig. 6 is an enlarged schematic sectional view of a joint of a robot on which the drive device is arranged; and [ Fig. 7] Fig. 7 is an enlarged schematic sectional view of a joint including a drive device which in turn includes a booster of a comparative example. Description of implementation examples

[0009] With reference to Fig. 1 to Fig. 7, a drive device and a robot incorporating the drive device of one embodiment are described below. The drive device of the present embodiment is arranged in a joint of the robot. The joint rotates one component of the robot relative to another component about a predetermined rotation axis.

[0010] Fig. 1 shows a perspective view of a robot of the present embodiment. Robot 1 of the present embodiment is an articulated robot including a plurality of joints 10a to 10f. Robot 1 of the present embodiment is a cooperative robot that can work together with the operator. The cooperative robot is configured such that the operation of robot 1 is restricted when a predetermined external force acts on robot 1.

[0011] The robot 1 includes a plurality of components rotatable at joints 10a to 10f. The components are configured to rotate about drive axes J1 to J6, which function as rotation axes. The drive device of the present embodiment is arranged within the joints 10a to 10f to drive the components of the robot 1. The robot of the present embodiment has six drive axes, but is not limited to this configuration. Robots that change their position and orientation with specific mechanisms can also be used.

[0012] The robot 1 of the present embodiment includes, as components of the robot 1, a base portion 14, a rotary base 13, an upper arm 12, a front arm 11, and a wrist 15. The rotary base 13 rotates about the drive axis J1 with respect to the base portion 14 fixed to the installation surface. The upper arm 12 rotates about the drive axis J2 with respect to the rotary base 13. The front arm 11 rotates about the drive axis J3 with respect to the upper arm 12. In addition, the front arm 11 rotates about the drive axis J4, which is parallel to the extending direction of the front arm 11. The robot 1 has a wrist 15 supported by the front arm 11. The wrist 15 rotates about the drive axis J5. In addition, the wrist 15 includes a flange 16 that rotates about the drive axis J6. A working tool corresponding to the activity performed by the device is attached to the flange 16.

[0013] Fig. 2 shows a sectional view of the drive device of the present embodiment. Referring to Fig. 1 and Fig. 2, in the robot 1 of the present embodiment, a drive device is arranged for each of the joints 10a to 10f. In other words, a separate drive device is provided for each joint. In the present embodiment, the drive device 2 for rotating the upper arm 12 about the drive axis J2 with respect to the rotary base 13 is described as an example. The drive device 2 is arranged at the joint 10b. The drive device 2 is arranged such that the direction indicated by an arrow 95 is, for example, the direction toward the rotary base 13.

[0014] The drive device 2 includes an electric motor 45, which in turn includes a rotor 45a and a stator 45b. The drive axis J2 corresponds to the rotational axis of the electric motor 45 and the axial direction of the drive device 2. The rotor 45a is attached to a shaft 21. The shaft 21, which transmits the rotational power of the electric motor 45, functions as the output shaft of the electric motor 45. The shaft 21 of the present embodiment is a hollow shaft having a cylindrical shape. The shaft 21 rotates with the drive axis J2 as the rotational axis.

[0015] The drive device 2 includes a torque sensor 27 that detects a torque output from the drive device 2. The torque sensor 27 detects a torque about the drive axis J2 when the drive device 2 is driven. The robot device includes the robot 1 and a robot controller that controls the robot 1. The robot controller receives a signal related to a torque via a communication cable that functions as a communication line. The robot controller subtracts the moment associated with the robot's own weight and the moment associated with the robot's operation from the torque detected by the torque sensor. The calculated moment corresponds to the external force acting on the robot.

[0016] The robot of the present embodiment is a cooperative robot. When the external force is greater than a predetermined determination value, the robot control device can restrict the operation of the robot. For example, when the operator touches the robot, the external force to be detected increases. The robot control device can stop the robot when the external force becomes greater than a determination value. The drive device of the present embodiment includes the torque sensor, but is not limited to this configuration. The torque sensor does not need to be arranged in the device.

[0017] A flange 26 is attached to the torque sensor 27 with a bolt 57. A flange 25 is attached to the flange 26 with a bolt 56. In the present embodiment, the torque sensor 27 and the flanges 25 and 26 are attached to the housing of the rotary base 13.

[0018] The drive device 2 includes an electric motor unit 4, which includes the electric motor 45. The electric motor unit 4 may include at least one device selected from the group consisting of a deceleration device, a brake, and a rotational position detection device. The devices are arranged coaxially in the direction of the rotational axis of the electric motor 45. The electric motor unit 4 of the present embodiment includes a deceleration device 31 that amplifies the rotational force of the electric motor 45, an electromagnetic brake 46 that functions as a brake for the shaft 21, and a sensor 47 that functions as a rotational position detection device and detects the rotational position of the output shaft of the electric motor 45. The torque sensor 27, the deceleration device 31, the electric motor 45, the electromagnetic brake 46, and the sensor 47 are arranged in a row in this order.It should be noted that at least one selected from the group of the deceleration device, the electromagnetic brake and the encoder does not have to be arranged in the electric motor unit.

[0019] The drive device 2 comprises a housing 22 within which the electric motor 45 is arranged. The housing 22 of the present embodiment is fastened to the housing of the upper arm 12. The shaft 21 is rotatably mounted in the bearings 51 and 52. The drive device 2 comprises a housing 23 within which the electromagnetic brake 46 is arranged. The housing 22 and the housing 23 are fastened to one another with a fastening element, such as a bolt. Furthermore, a bearing fastening element 28 for fastening the bearing 52 is arranged between the housing 22 and the housing 23. The bearing fastening element 28 is fastened to the housing 23 with a fastening element, such as a bolt. The housings 23 and 22 and the bearing fastening element 28 can be removed from the side opposite the direction indicated by the arrow 95 by loosening the fastening element.

[0020] A protective tube 66 is arranged on an inner side of the shaft 21. The protective tube 66 is formed in a cylindrical shape along the inner side of the shaft 21. A wire body, e.g., an electrical wire such as a power cable, an air hose that supplies compressed air, or a communication cable, is inserted into the protective tube 66. The protective tube 66 is fixed to a junction portion 66a sandwiched between the flange 26 and the torque sensor 27. With the protective tube 66 arranged, the wire body can be arranged inside the joint 10b of the robot 1.

[0021] The shaft 21 of the present embodiment includes a stepped portion 21a and a stepped portion 21b for limiting movement in the extending direction of the rotational axis of the shaft 21. The bearings 51 and 52 engage with the stepped portion 21a and the stepped portion 21b. The bearing 51 is fixed by the housing 22, and the bearing 52 is fixed by the bearing fixing member 28.

[0022] The deceleration device 31 of the drive device 2 transmits the rotational force output from the electric motor 45 to the housing 22. The deceleration device 31 of the present embodiment is a wave gear deceleration device. The deceleration device 31 includes a wave generating element 32 that functions as an input section to which the rotational force is input. The wave generating element 32 is referred to as a wave generating device. The wave generating element 32 includes a hub 36 that has the shape (planar shape) of an ellipse viewed in the direction of the rotation axis, and a ball bearing 37 arranged on the outer peripheral surface of the hub 36. The hub 36 functions as a cam that has an elliptical, planar shape. The hub 36 is fixed to the shaft 21, for example, by a key connection or the like.

[0023] The deceleration device 31 includes an elastic cylindrical member 33 that is elastically deformable. The elastic cylindrical member 33 is referred to as a flexspline. The elastic cylindrical member 33 includes a plurality of first tooth portions 33a formed on the outer peripheral surface. The elastic cylindrical member 33 is configured to deform upon rotation of the hub 36. The elastic cylindrical member 33 of the present embodiment is fixed to the housing 22 with a bolt 55. The elastic cylindrical member 33 functions as the output shaft of the deceleration device 31.

[0024] The deceleration device 31 includes an annular element 34 arranged on an outer side of the elastic cylindrical element 33. The annular element 34 is referred to as a circular spline. The annular element 34 consists of a rigid element that does not deform elastically. A second tooth portion, which engages with the first tooth portion 33a, is formed on the inner peripheral surface of the annular element 34.

[0025] A main bearing 41 is arranged on the lateral side of the annular member 34. The main bearing 41 of the present embodiment is a crossed roller bearing. The main bearing 41 includes an inner ring 41a and an outer ring 41b. The inner ring 41a is fixed to the flange 25 and the annular member 34 with a bolt 39. The outer ring 41b is fixed to the elastic cylindrical member 33 together with the housing 22 with the bolt 55. In the present embodiment, the wave generating member 32 is rotatable, but the annular member 34 is non-rotatable. When disassembling the drive device 2, the bolts 56 and 57 are loosened to detach the torque sensor 27 and the flange 26 from the flange 25. By loosening the bolt 39 and the bolt 55, the deceleration device 31 and the main bearing 41 can be detached from the housing 22.

[0026] The hub 36 of the wave-generating element 32 has an elliptical shape, so that the first tooth portion 33a of the elastic cylindrical member 33 and the second tooth portion of the annular member 34 mesh with each other in the major axis direction of the ellipse. The number of teeth of the first tooth portion 33a of the elastic cylindrical member 33 is smaller than the number of teeth of the second tooth portion of the annular member 34. The number of teeth differs by, for example, two. When the wave-generating element 32 makes one revolution, the elastic cylindrical member 33 rotates slightly by a reduction ratio corresponding to the difference in the number of teeth of the tooth portion.

[0027] The decelerated rotational force is transmitted to the housing 22 and the outer ring 41b of the main bearing 41, which is fixed to the elastic cylindrical member 33. The housing 22 of the drive device 2 is fixedly connected to the housing of the upper arm 12. When the drive device 2 is driven, the upper arm 12 rotates with respect to the rotary base 13.

[0028] Oil seals 61 and 62 are arranged on the outer peripheral surface of the shaft 21 to prevent the lubricating oil inside from leaking out or to prevent the ingress of foreign matter from the outside. Furthermore, an oil seal 63 is arranged to prevent the lubricating oil inside the main bearing 41 from leaking out or to prevent the ingress of foreign matter from the outside.

[0029] The drive device 2 of the present embodiment includes an amplifier 5 that functions as an electric motor control unit that supplies power to the electric motor 45. The amplifier 5 is also referred to as a driver for driving the electric motor 45. The amplifier 5 of the present embodiment is fixed to an end portion of the electric motor unit 4 in the axial direction. Specifically, the amplifier 5 is coaxially fixed to an end surface of the electric motor unit 4. The amplifier 5 is arranged at the outermost end of the components included in the drive device 2. The amplifier 5 is arranged coaxially with the electric motor unit 4, which includes the electric motor 45. The torque sensor 27 is arranged at an end portion on the side opposite to an end portion of the electric motor unit 4 on which the amplifier 5 is arranged.

[0030] The amplifier 5 of the present embodiment receives operation commands from the robot control device and controls the value and frequency of the current to be supplied to the electric motor 45 based on the operation command. The amplifier 5 includes an electrical circuit that generates the current for the electric motor 45. In the drive device of the present embodiment, the amplifier 5 is arranged for each electric motor. One amplifier 5 is arranged for each electric motor 45, but it is not limited to this configuration. One amplifier may be arranged for a plurality of electric motors. In other words, one amplifier may be arranged to supply current to a plurality of electric motors.

[0031] Fig. 3 is an electrical circuit diagram showing the amplifier of the present embodiment. The robot control device 3 is arranged remotely from the robot 1, for example. The robot control device 3 includes a calculation processing unit including a CPU (Central Processing Unit) functioning as a processor. The robot control device 3 outputs operation commands to the drive devices arranged in the joints 10a to 10f. The alternating current from the alternating current source 7 is converted into direct current by a rectifier 8. The amplifier 5 of the present embodiment functions as an inverter, converting the direct current from the rectifier 8 into the alternating current.

[0032] The amplifier 5 includes a capacitor 73 for smoothing the direct current. The amplifier 5 includes a main circuit 70 that generates a three-phase alternating current from the direct current. The main circuit 70 is a bridge circuit with a current element 74, such as a MOSFET (metal-oxide-semiconductor field-effect transistor). The amplifier 5 includes a processor 83, e.g., an MCU (microcontroller unit), which outputs operating commands to each current element 74 of the main circuit 70.

[0033] The processor 83 receives the operating command for driving the electric motor 45 from the robot controller 3. The processor 83 receives the output signal of the encoder 47, which detects the rotational position of the electric motor 45. Furthermore, a current detection sensor 75 is arranged at the output of the power cable of the main circuit 70. The processor 83 receives the output signal of the current detection sensor 75.

[0034] The processor 83 outputs a switching command to the main circuit 70 based on the operation command of the robot control device 3. The processor 83 can output commands for controlling the current element 74 based on the output signal of the encoder 47, the output signal of the current detection sensor 75, and the output signal of the torque sensor 27. The plurality of electrical components, such as the processor 83, the capacitor 73, and the current element 74, are arranged on the surface of the substrate included in the amplifier 5.

[0035] The drive device 2 of the present embodiment includes a wire body for connecting to an external device. The wire body includes a power cable for supplying power and a communication cable for transmitting signals. The wire body of the present embodiment includes a connecting element arranged at a distal end of the cable for connecting it to the substrate. The connecting element of the wire body is connected to the element of the substrate.

[0036] The connecting element of the wire body of the present embodiment is formed from a connector. A connector that matches the connector of the wire body is provided on the amplifier substrate. For example, a female connector is arranged on the substrate. The male connector located at the distal end of the wire body is inserted or removed. In this way, the wire body connector is configured to be attached to the connector of the amplifier substrate or detached from the connector of the substrate by the operator.

[0037] The connecting element of the wire body is not limited to the connector; any element that can be attached to or detached from the elements of the amplifier substrate can be used. For example, a crimp connection can be used as the connecting element of the wire body. A terminal base can be attached to the substrate with a screw to secure the crimp connection.

[0038] With the wire body including the connecting element configured to be attached to or detached from the elements of the amplifier's substrate, the wire body can be easily detached from or attached to the substrate. This allows the amplifier to be easily detached from or attached to the robot or electric motor unit.

[0039] The command from the robot control device 3 is input to the processor 83 via a connector 82a arranged on the substrate. The output signal of the encoder 47 is input to the processor 83 via a connector 82b. The output signal of the current detection sensor 75 is input to the processor 83 via a connector 82c. The command output from the processor 83 is output to the main circuit 70 via a connector 77.

[0040] Furthermore, the current converted into direct current at the rectifier 8 is input to the main circuit 70 via a connector 72ba arranged on the substrate. Furthermore, the alternating currents of the U-phase, V-phase, and W-phase supplied from the main circuit 70 are supplied to the electric motor 45 via a connector 72a arranged on the substrate.

[0041] Fig. 4 shows a perspective view of the amplifier of the present embodiment. Fig. Figure 5 shows a schematic plan view of the amplifier of the present embodiment. Referring to Fig. 2 to Fig. 5, arrow 95 indicates a direction in which the electric motor 45 is arranged relative to the amplifier 5. Arrow 95 indicates a direction along the drive axis J2 as the rotation axis of the electric motor 45.

[0042] The amplifier 5 of the present embodiment includes two substrates on which electrical components are arranged. The amplifier 5 includes a power substrate 71 on which an electrical component for supplying power to the electric motor 45 is arranged. The amplifier 5 includes a control substrate 81 on which electrical components for generating command signals for controlling the main circuit 70 are arranged. The power substrate 71 and the control substrate 81 are each arranged to intersect the extension direction of the drive axis J2.

[0043] In the present embodiment, the power substrate 71 and the control substrate 81 each have a maximum surface area. The majority of electrical components are arranged in the maximum surface area. The power substrate 71 and the control substrate 81 are arranged such that the maximum surface areas intersect perpendicularly with the drive axis J2. Furthermore, the power substrate 71 and the control substrate 81 are arranged such that the maximum surface areas are parallel to each other.

[0044] In the amplifier of the present embodiment, the substrate on which the electronic component is arranged is formed of the power substrate and the control substrate, but is not limited to this configuration. The number of substrates on which the electronic component is arranged may be one. Alternatively, three or more substrates may be arranged.

[0045] The control substrate 81 is fixed to the power substrate 71 with an interval bolt 67a. An interval bolt 67a fixes the control substrate 81 with a nut 67c. Another interval bolt 67a fixes the control substrate 81 by sandwiching the control substrate 81 with it and an interval bolt 67b. The control substrate 81 is fixed to the metal bracket 68 with the interval bolt 67b. The control substrate 81 is sandwiched by the interval bolt 67a and the interval bolt 67b.

[0046] The metal fitting 68 is annular. The metal fitting 68 is a member for fastening the amplifier 5 to the housing 23 of the electric motor unit 4. The metal fitting 68 includes a screw hole 68c for fastening the interval bolt 67b. In the present embodiment, the power substrate 71, the control substrate 81, and the metal fitting 68 are firmly connected to the interval bolts 67a and 67b. The method for fastening the plurality of substrates is not limited to this embodiment, and they can be fastened to each other using any suitable members.

[0047] The amplifier 5 of the present embodiment is designed to be detachable from the electric motor unit 4 by the operator's operation, and the metal fitting 68 includes a projection 68a projecting outward in the radial direction. A hole 68b is formed in the projection 68a for inserting the bolt 69, which functions as a fastening element. Referring to Fig. 2, a projection 23a is formed on one end portion of the housing 23 of the electric motor unit 4, projecting radially outward. A screw hole is formed in the projection 23a. The projection 68a of the metal fitting 68 is secured to the projection 23a of the housing 23 by the bolt 69. In this way, the amplifier 5 is directly secured to the end portion of the electric motor unit 4 by the bolt 69. The operator can remove the amplifier 5 from the drive device 2 by loosening the bolt 69.

[0048] A through-hole 71c is formed in a central portion of the power substrate 71. Furthermore, a through-hole 81c is formed in a central portion of the control substrate 81. The shaft 21 and the protective tube 66 are inserted into the through-holes 71c and 81c.

[0049] With reference to Fig. 2 to Fig. 5, capacitors 73a, 73b, and 73c with the function of smoothing the direct current are arranged on the power substrate 71. The connector 72a for supplying power to the electric motor 45 is arranged on the power substrate 71. The connector 72ba, to which a power cable 86a for receiving power from the rectifier 8 is connected, is arranged on the power substrate 71. A connector 72bb is arranged on the power substrate 71, to which a power cable 86b for supplying power to other drive devices is connected. Furthermore, a connector 72c for supplying power to the electromagnetic brake 46 is arranged on the power substrate 71.

[0050] The plurality of power elements 74 included in the main circuit 70 are arranged in the maximum surface area of ​​the power substrate 71. Furthermore, the current detection sensor 75 is arranged for detecting the current output by the main circuit 70. The connector 77 for communicating with the electrical circuit of the control substrate 81 is arranged on the power substrate 71. The connector 77 is configured to fit the connector arranged on the back of the control substrate 81.

[0051] The control substrate 81 has a shape achieved by cutting out the outer periphery of a portion of the circular substrate. The control substrate 81 includes a notch 81d. The connectors 72a, 72ba, 72bb, and 72c and the capacitors 73a, 73b, and 73c of the power substrate 71 are arranged on an outer side of the notch 81d.

[0052] The processor 83, which outputs a command to the main circuit 70, is arranged on the control substrate 81. A processing circuit 84 for processing input data is arranged on the control substrate 81. The plurality of drive devices of the robot 1 of the present embodiment are configured to perform serial communication with each other. One drive device is connected to the other drive device via a communication cable. A connector 82aa is arranged on the control substrate 81, to which a communication cable 87a for receiving the signal of the robot control device 3 from the other drive device is connected. A connector 82ab is arranged on the control substrate 81, to which a communication cable 87b for transmitting the signal from the robot control device 3 to the other drive device is connected.

[0053] Furthermore, the control substrate 81 has a connector 82b to which a signal cable for receiving the signal from the encoder 47 is connected. Also provided is a connector 82c to which a signal cable for receiving the signal from the current detection sensor 75 is connected. A connector may also be provided to which a signal cable for receiving the signal from the torque sensor 27 is connected.

[0054] Fig. 6 shows an enlarged schematic sectional view of the joint when the drive device of the present embodiment is arranged in the joint of the robot. Fig. 6 shows a schematic sectional view of the joint 10b that rotates the upper arm 12 acting as another component with respect to the rotary base 13 acting as a component of the robot 1.

[0055] Referring to Fig. 2 and Fig. 6, the torque sensor 27 of the drive device 2 includes a screw hole 27a. A protruding portion 13ab is formed in a housing 13a of the rotary base 13. A through hole is formed in the protruding portion 13ab. The torque sensor 27 is secured to the housing 13a of the rotary base 13 by a bolt 58 that is inserted through the through hole of the protruding portion 13ab and secured to the screw hole 27a.

[0056] Furthermore, the housing 22 of the electric motor unit 4 includes a screw hole 22a. The housing 12a of the upper arm 12 includes a protruding portion 12ac that projects inward. A through hole is formed in the protruding portion 12ac. The housing 22 of the drive device 2 is secured to the housing 12a of the upper arm 12 by a bolt 59 that is inserted through the through hole and secured to the screw hole 22a.

[0057] As described above, when the electric motor 45 is driven, the housing 22 of the electric motor unit 4 rotates together with the elastic cylindrical member 33 of the deceleration device 31. In addition, the housing 12a of the upper arm 12, which is fixed to the housing 22 of the electric motor unit 4, rotates together with the housing 22. As a result, the upper arm 12 rotates about the drive axis J2 with respect to the rotary base 13.

[0058] The power cable 86a and the communication cable 87a are inserted into the protective tube 66. The power cable 86a and the communication cable 87a are connected to the drive device arranged in an adjacent joint 10a. As shown in the Fig. 4 and Fig. As shown in Figure 6, the power cable 86a is connected to the connector 72ba. Furthermore, the power cable 86b is connected to the connector 72bb. The power cable 86b is connected to the drive device located in an adjacent joint 10c.

[0059] In the plurality of drive devices of the robot 1 of the present embodiment, the information transmitted via the communication cables 87a and 87b for performing mutual serial communication may include, in addition to the operation command, information detected by the sensor disposed in the robot 1. The communication cable 87a is connected to the drive device 2 of the connector 82aa. Furthermore, the communication cable 87b, which is connected to the connector 82ab of the drive device 2, is connected to the drive device of the adjacent joint 10c. In this way, the drive device 2 is disposed within the component housing of the robot 1.

[0060] The housing 12a of the upper arm 12 of the present embodiment includes a body portion 12aa and a cover 12ab that is detachable from the body portion 12aa. The cover 12ab is attached to the body portion 12aa with a fastener not shown in the drawing.

[0061] The cover 12ab is arranged to face the drive device 2. The cover 12ab has a size corresponding to the area where the drive device 2 is arranged. The cover 12ab has a shape that allows the operator to see the entire end portion of the drive device 2 when the cover 12ab is removed. In the present embodiment, the cover 12ab is radially larger than the drive device 2. Furthermore, the cover 12ab is larger than the end surface of the amplifier 5.

[0062] With reference to Fig. 4 to Fig. 6, the power substrate 71 is substantially circular and planar. A recess 71a is formed on the outer periphery of the power substrate 71. The recess 71a is formed to correspond to the position of the bolt 69 for fastening the amplifier 5 to the housing 23. In other words, the recess 71a is formed at a position corresponding to the hole 68b of the metal fitting 68. Like the power substrate 71, the control substrate 81 also has a recess 81a formed on its outer periphery. The recess 81a is formed to correspond to the position of the hole 68b of the metal fitting 68.

[0063] Through the recesses 71a and 81a, the operator can operate the bolt 69 for fastening the amplifier 5 to the electric motor unit 4 from the outside of the drive device 2. When detaching the amplifier 5 from the electric motor unit 4, the operator can operate the bolt 69 through the recesses 71a and 81a. By loosening the bolt 69, the amplifier 5 can be separated in one piece from the electric motor unit 4, with the electric motor unit 4 attached to the robot. Alternatively, the amplifier 5 can also be attached to the electric motor unit 4 while the electric motor unit 4 is fixed to the robot.

[0064] With the hinge 10b of the present embodiment, the operator can operate the bolt 69 that secures the amplifier 5 to the housing 23 by removing the cover 12ab. The operator can remove the bolt 69 through the recess 71a formed in the power substrate 71 and the recess 81a formed in the control substrate 81.

[0065] By loosening the bolt 69, the operator can remove the amplifier 5 from the electric motor unit 4. The amplifier 5 can be completely removed outward from the housing 12a. Then, the wire body connector is pulled out from the connectors 72a, 72ba, 72bb, and 72c of the power substrate 71. Furthermore, the amplifier 5 can be separated from the electric motor unit 4 by pulling the wire body connector out of the connectors 82aa, 82ab, 82b, and 82c arranged on the control substrate 81.

[0066] In this way, in the drive device 2 of the present embodiment, it is possible to detach only the amplifier 5 from the drive device 2 without detaching the entire drive device 2 from the robot 1. Furthermore, the amplifier can be inspected or replaced. When attaching the amplifier 5 to the electric motor unit 4, the amplifier 5 can be fixed to the housing 23 of the electric motor unit 4 with the bolt 69 after the connector of each wire body is inserted into the connector of the substrate.

[0067] When the drive device 2 is removed from the housings 12a and 13a and the amplifier 5 is removed from the drive device 2, the operator can operate the bolt 59 with which the electric motor unit 4 is attached to the housing 12a. The operator can remove the drive device 2 from the housings 12a and 13a by loosening the bolts 58 and 59.

[0068] Fig. Figure 7 shows a schematic view of a drive device in a joint of a comparative example. A drive device 91 of the comparative example includes an amplifier 92. The amplifier 92 of the comparative example includes a plurality of substrates. The amplifier 92 is coaxially mounted with the electric motor unit 4 at one end portion of the electric motor unit 4.

[0069] The drive device 91 of the comparative example does not include a torque sensor. The drive device 91 includes a encoder 93 instead of the torque sensor. Two encoders 47 and 93 are arranged in the drive device 91. The encoder 47 is a primary encoder (first encoder) that detects the rotational position of the shaft 21, which is the output shaft of the electric motor 45. The encoder 93 is a secondary encoder (second encoder) that detects the rotational position of the output shaft of the electric motor unit 4. The encoder 93 detects the rotational position of a member that rotates together with the output shaft of the deceleration device 31. The end surface of the protective tube 66 is connected to the encoder 93.

[0070] The robot control device can calculate the amount of torsion of the output shaft of the deceleration device 31 relative to the drive shaft of the deceleration device 31 (the output shaft of the electric motor 45) based on the rotational position output from the encoder 47, the reduction ratio of the deceleration device 31, and the rotational position output from the encoder 93. The robot control device can calculate the torque generated by the drive device 91 based on the amount of torsion. Furthermore, the external force acting on the robot components can be calculated based on the torque of the drive device 91.

[0071] In the drive device 91 of the comparative example, the encoder 93 is arranged as a secondary encoder to calculate the torque generated by the drive device 91. The encoder 93 is arranged at the outermost end of the drive device 91. In other words, the electric motor 45, the electromagnetic brake 46, the encoder 47, the amplifier 92, and the encoder 93 are arranged in this order.

[0072] Similarly, in the drive device 91 of the comparative example, the operator can view the entire portion of the drive device 91 by removing the cover 12ab from the housing 12a. However, since the encoder 93 is located at the outermost portion of the drive device 91, it is impossible to detach only the amplifier 92 from the drive device 91. When replacing the amplifier 92, the entire drive device 91 must be removed from the housings 12a and 13a of the robot 1.

[0073] On the other hand, in the drive device 2 of the present embodiment, the torque sensor is arranged instead of the secondary encoder (see Fig. 6). The drive device 2 has a configuration that does not include a rotational position detecting device that detects the rotational position of the output shaft of the electric motor unit 4. The torque sensor 27 may be mounted on the output shaft of the deceleration device 31 or on the mounting shaft of the deceleration device 31. The amplifier 5 may be mounted on the end portion of the electric motor unit 4. Furthermore, the torque sensor 27 may be arranged at an end portion on the opposite side to an end portion of the electric motor unit 4 where the amplifier 5 is mounted.

[0074] The amplifier 5 of the present embodiment is arranged at the outermost end in the axial direction of the drive device 2. When replacing or inspecting the amplifier 5, the operator can easily separate the amplifier 5 from the electric motor unit 4. It should be noted that the drive device may include both the torque sensor and the secondary encoder. In this case, it is preferable to arrange the amplifier on the outer side of the secondary encoder in the axial direction of the drive device, so that the amplifier is arranged at the outermost end of the drive device.

[0075] With reference to Fig. 7, in the drive device 91 of the comparative example, it is not possible to remove only the amplifier 92 from the drive device 91. When the amplifier 92 is replaced, the drive device 91 must be detached from the robot. In this case, to detach the drive device 91 from the housing 12a of the upper arm 12, a working space must be created around the drive device 91 so that the operator can operate the bolt 59. Therefore, the substrate of the amplifier 92 is formed so small that a working space is created around the amplifier 92. In other words, the substrate of the amplifier 92 is formed so small that the operator can operate the bolt 59.

[0076] For example, the substrate of the amplifier 92 may be formed such that the diameter DS is less than or equal to the diameter of the electric motor unit 4. Alternatively, the substrate of the amplifier 92 may be formed such that the diameter DS is less than or equal to an inner diameter DF of the protrusion portion 12ac of the housing in which the bolt 69 is arranged. Therefore, in the drive device 91 of the comparative example, it is difficult to provide the amplifier 92 with a large diameter. As a result, the number of substrates of the amplifier may increase, and the axial length of the amplifier may increase. Furthermore, a large number of substrates may complicate the structure of the amplifier.

[0077] On the other hand, in the drive device 2 of the present embodiment, the amplifier 5 can be removed from the drive device 2 at the beginning (see FIG. Fig.6). In this way, it is sufficient to detach the amplifier 5 from the drive device 2, even if the bolt 59 is hidden by the substrate of the amplifier 5 and cannot be operated when the cover 12ab is removed. In this way, the size of the substrate of the amplifier 5 can be increased. In the present embodiment, the power substrate 71 and the control substrate 81 are formed such that the maximum surface area of ​​the substrate is large.

[0078] For example, the amplifier substrate may be formed larger than at least one selected from the group consisting of the electric motor, the deceleration device, the brake, and the rotational position detecting device in the radial direction. Alternatively, the amplifier substrate may be formed with a diameter larger than the diameter at the position of the bolt 59. Alternatively, the amplifier substrate may be formed with a size larger than the inner diameter of the protrusion portion 12ac, which functions as the fastening portion of the housing, in which the bolt 59 is arranged.

[0079] In the drive device of the present embodiment, the maximum surface area of ​​the substrate on which the electrical component is mounted can be increased, and a large number of electrical components can be mounted on a single substrate. The increase in the number of substrates and the increase in the size of the amplifier can be avoided.

[0080] In the present embodiment, the amplifier 5 is fixed to the end surface of the electric motor unit 4, with the bolt 69 functioning as a fastening member. With this configuration, the amplifier 5 can be easily detached from the electric motor unit 4 by loosening the bolt 69. The member for fixing the amplifier to the electric motor unit is not limited to fixing members such as screws, bolts, and nuts, but any member may be used. For example, a claw portion is formed in one of the amplifier and the housing of the electric motor unit. An engaging portion is attached to the other member to engage with the claw portion. It is possible to use a structure for fixing the amplifier to the electric motor unit by engaging the claw portion with the engaging portion.

[0081] In the present embodiment, the wave gear deceleration device is used as the deceleration device, but it is not limited to this configuration. Any deceleration device, such as a gear deceleration device, can be used. Furthermore, it is preferable to use a deceleration device that can be arranged coaxially with the electric motor, with the input and output shafts on the same straight line. For example, a planetary gear can be used as the deceleration device.

[0082] The drive device for driving the components around the drive axis J2 of the robot is described in the present embodiment, but this embodiment is not limiting. The drive device of the present embodiment can be used for a drive device for driving a specific component of the robot.

[0083] Furthermore, the drive device of the robot of the present embodiment is arranged at the joint, but is not limited to this configuration. The drive device of the present embodiment is applicable to any device for relative rotation of two different elements around the rotation axis. For example, the drive device of the present embodiment is applicable to a drive device for driving the wheel of an unmanned vehicle, a drive device arranged in an operating tool for driving the components of the operating tool, a drive device of an automatic tool changing device of a machine tool, or the like.

[0084] The above-described embodiments can be combined as desired. In each of the above-described drawings, identical or equivalent portions are designated by the same reference numerals. The above-described embodiments are examples and do not limit the invention. Furthermore, the embodiments include the modifications of the embodiments defined in the claims. List of reference symbols 1 robot 2 drive device 4 Electric motor unit 5 amplifiers 10a to 10f joint 12 upper arm 12a housing 13 Rotating base 13a Housing 21 Wave 27 Torque sensor 27a screw hole 31 Delay device 45 electric motor 46 electromagnetic brake 47 sensors 71 Current substrate 72a, 72ba, 72bb, 72c connectors 81 Tax substrate 82aa, 82ab, 82b, 82c connectors 86a, 86b power cable 87a, 87b Communication cables QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2010-41747 A [0002, 0003] JP 2019-84607 A

[0003]

Claims

[1] Drive device comprising: an electric motor unit comprising an electric motor, and an electric motor control unit configured to supply power to the electric motor, wherein the electric motor unit comprises at least one device selected from a group consisting of a deceleration device, a brake and a rotational position detection device, the electric motor control unit comprises a substrate and a plurality of electrical components mounted on the substrate, and the electric motor control unit is coaxially fixed to an end portion of the electric motor unit in a direction of a rotation axis of the electric motor and is configured to be detachable from the electric motor unit by an operation by an operator. [2] The drive device according to claim 1, wherein the electric motor control unit is fixed to the end portion of the electric motor unit with a fixing member. [3] A drive device according to claim 1 or 2, comprising a wire body for connection to an external device, wherein the wire body comprises a connecting element for connecting to the substrate, and the connecting element is designed such that it can be attached to an element of the substrate or detached from the element of the substrate. [4] Drive device according to claim 3, wherein the connecting element comprises a connector or a crimp connection. [5] Drive device according to one of claims 1 to 4, wherein the substrate is formed larger in a radial direction than at least one device selected from the group of the electric motor, the deceleration device, the brake and the rotational position detecting device. [6] A drive device according to any one of claims 1 to 5, comprising a torque sensor configured to detect a torque output from the electric motor unit, the torque sensor being arranged at an end portion on a side opposite to an end portion of the electric motor unit at which the electric motor control unit is arranged. [7] The drive device according to any one of claims 1 to 6, wherein the electric motor unit has a configuration including a rotational position detecting means configured to detect a rotational position of an output shaft of the electric motor and not including a rotational position detecting means configured to detect a rotational position of an output shaft of the electric motor unit. [8] Drive device according to one of claims 1 to 7, wherein the electric motor control unit is arranged for each electric motor. [9] Robot that includes: the drive device according to claim 1; and a joint configured to rotate one component of the robot with respect to another component of the robot, wherein the drive device is arranged on the joint.

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