Robot

Abstract

To provide a robot which is effective to improvement of accuracy of rotation detection by a rotation sensor which detects a joint angle directly.SOLUTION: A robot 2 includes: a first link and a second link connected with each other at a joint axis Ax; a rotation part 50 which is fixed to the second link and rotates around the joint axis Ax relative to the first link; a rotation sensor 40 which is held by the holding member 70 to detect rotation of the rotation part 50; and a holding member 70 which is fixed to the first link, holds the rotation sensor 40, and holds the rotation part 50 so that the rotation part 50 may rotate around the joint axis Ax.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to robots. [Background technology]

[0002] Patent Document 1 discloses a robot that includes a motor, a reducer that transmits the driving force of the motor to a link, and a detector that detects the rotation angle of the output shaft of the reducer. The detector is connected to the output shaft of the reducer via a shaft coupling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-171072 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a robot that is effective in improving the accuracy of rotation detection using a rotation sensor that directly detects joint angles. [Means for solving the problem]

[0005] A robot according to one aspect of the present disclosure includes a first link and a second link connected to each other at a joint axis, a rotating part fixed to the second link and rotating around the joint axis relative to the first link, a rotation sensor held by a holding member and detecting rotation of the rotating part, and a holding member fixed to the first link, holding the rotation sensor, and holding the rotating part so that it can rotate around the joint axis. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a robot that is effective in improving the accuracy of rotation detection by a rotation sensor that directly detects joint angles. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a robot system. [Figure 2] FIG. 2 is a schematic diagram illustrating a peripheral structure of a rotation sensor. [Figure 3] 10A and 10B are schematic diagrams showing modified examples of the peripheral structure of the rotation sensor; [Figure 4] 10A and 10B are schematic diagrams showing other modified examples of the peripheral structure of the rotation sensor; [Figure 5] FIG. 10 is a schematic diagram showing yet another modified example of the peripheral structure of the rotation sensor. [Figure 6] FIG. 10 is a schematic diagram illustrating the connection of a rotation sensor to a robot controller. [Figure 7] FIG. 10 is a schematic diagram illustrating the connection of a motor rotation sensor to a robot controller. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and redundant description will be omitted.

[0009] 1 is a system that causes a robot 2 to perform a task on a workpiece. Examples of tasks performed on a workpiece include assembly, welding, painting, inspection, and transportation. For example, the robot system 1 includes the robot 2 and a robot controller 3 that controls the robot 2.

[0010] The robot 2 is a serial link type robot having at least one pair of links connected to each other at a joint axis. For example, the robot 2 is a vertical articulated robot having links 11, 12, 13, 14, 15, 16, and 17, an end effector 18, motors 20A, 20B, 20C, 20D, 20E, and 20F, motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F, and rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F.

[0011] The link 11 is the base of the robot 2 and is fixed on an installation surface. The installation surface may be the floor surface of the workspace or a wall surface of the workspace. The installation surface may also be the top surface of a moving body such as an automated guided vehicle. For convenience, the side facing the installation surface will be referred to as "upward" below.

[0012] Link 12 is a rotating part provided on link 11. Link 11 and link 12 are connected to each other at a joint axis Ax1 perpendicular to the installation surface, and link 12 rotates around joint axis Ax1 with respect to link 11. The rotation of one object with respect to another object means that the one object rotates relative to the other object. For example, the rotation of one object with respect to another object includes a state in which the one object is stationary and the other object is rotating in the absolute coordinate system. The same applies hereinafter.

[0013] Link 13 is connected to link 12. Link 12 and link 13 are connected to each other at joint axis Ax2 that intersects (e.g., is perpendicular to) joint axis Ax1, and link 13 rotates around joint axis Ax2 relative to link 12. Intersection includes a torsional relationship, such as a three-dimensional intersection. The same applies hereinafter. Link 13 extends away from joint axis Ax2.

[0014] Link 14 is connected to the tip of link 13. Link 13 and link 14 are connected to each other at joint axis Ax3 parallel to joint axis Ax2, and link 14 rotates around joint axis Ax3 relative to link 13. Link 14 extends away from joint axis Ax3 along joint axis Ax4 that intersects (e.g., is perpendicular to) joint axis Ax3.

[0015] Link 15 is connected to the tip of link 14 and extends along joint axis Ax4 away from link 14. Link 14 and link 15 are connected to each other at joint axis Ax4, and link 15 rotates relative to link 14 around joint axis Ax4.

[0016] Link 16 is connected to the tip of link 15. Link 15 and link 16 are connected to each other at a joint axis Ax5 that intersects (e.g., is perpendicular to) the joint axis Ax4, and link 16 rotates around the joint axis Ax5 relative to link 15. Link 16 extends away from the joint axis Ax5 along a joint axis Ax6 that intersects (e.g., is perpendicular to) the joint axis Ax5.

[0017] The link 17 is connected to the tip of the link 16. It spreads out like a flange along a plane intersecting (for example, perpendicular to) the joint axis Ax6. The links 16 and 17 are connected to each other at the joint axis Ax6, and the link 17 rotates around the joint axis Ax6 relative to the link 16. An end effector 18 is attached to the link 17. The end effector 18 acts on a workpiece when performing an operation on the workpiece. Examples of the end effector 18 include a gripper, a welding torch, a paint nozzle, a tool holder, etc.

[0018] With the above configuration, the robot 2 has joints J1, J2, J3, J4, J5, and J6 corresponding to the joint axes Ax1, Ax2, Ax3, Ax4, Ax5, and Ax6, respectively. Motors 20A, 20B, 20C, 20D, 20E, and 20F drive the joints J1, J2, J3, J4, J5, and J6, respectively. For example, motor 20A rotates link 12 around joint axis Ax1 relative to link 11. For example, motor 20B rotates link 13 around joint axis Ax2 relative to link 12. For example, motor 20C rotates link 14 around joint axis Ax3 relative to link 13. For example, motor 20D rotates link 15 around joint axis Ax4 relative to link 14. For example, motor 20E rotates link 16 around joint axis Ax5 relative to link 15. For example, the motor 20F rotates the link 17 relative to the link 16 around the joint axis Ax6.

[0019] Each of the motors 20A, 20B, 20C, 20D, 20E, and 20F is, for example, a servo motor. Each of the motors 20A, 20B, 20C, 20D, 20E, and 20F has an output shaft 21 (see FIG. 2), and the output shaft 21 is rotated by driving power supplied from the robot controller 3. Each of the multiple joints is driven by the rotation of the output shaft 21.

[0020] Motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F detect the rotation of motors 20A, 20B, 20C, 20D, 20E, and 20F, respectively. For example, motor rotation sensor 30A detects the rotation of motor 20A (rotation of output shaft 21 by motor 20A) for rotating link 12 relative to link 11. Motor rotation sensor 30B detects the rotation of motor 20B for rotating link 13 relative to link 12. Motor rotation sensor 30C detects the rotation of motor 20C for rotating link 14 relative to link 13. Motor rotation sensor 30D detects the rotation of motor 20D for rotating link 15 relative to link 14. Motor rotation sensor 30E detects the rotation of motor 20E for rotating link 16 relative to link 15. Motor rotation sensor 30F detects the rotation of motor 20F for rotating link 17 relative to link 16.

[0021] Detecting rotation means generating a signal (e.g., an electrical signal or an optical signal) representing the rotation in response to the rotation. For example, each of the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F may be a rotary encoder that generates a signal corresponding to the rotation angle, or may be a potentiometer or a resolver that generates a voltage corresponding to the rotation angle.

[0022] The rotation of motors 20A, 20B, 20C, 20D, 20E, and 20F correlates with the rotation of joints J1, J2, J3, J4, J5, and J6. Therefore, the rotation of joints J1, J2, J3, J4, J5, and J6 can be indirectly detected based on the detection results of motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F. In contrast, rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F directly detect the rotation of joints J1, J2, J3, J4, J5, and J6.

[0023] For example, rotation sensor 40A directly detects the rotation of link 12 relative to link 11 (rotation of link 11 relative to link 12). Directly detecting the rotation of link 12 relative to link 11 includes detecting the relative rotation between a member fixed to link 11 and a member fixed to link 12.

[0024] For example, rotation sensor 40A is fixed to link 12 (first link). Rotation sensor 40A detects the rotation of rotating part 50A fixed to link 11 (second link) relative to link 12 (first link). Rotation sensor 40B is fixed to link 12 (first link). Rotation sensor 40B detects the rotation of rotating part 50B fixed to link 13 (second link) relative to link 12 (first link). Rotation sensor 40C is fixed to link 14 (first link). Rotation sensor 40C detects the rotation of rotating part 50C fixed to link 13 (second link) relative to link 14 (first link). Rotation sensor 40D is fixed to link 14 (first link). Rotation sensor 40D detects the rotation of rotating part 50D fixed to link 15 (second link) relative to link 14 (first link). The rotation sensor 40E is fixed to the link 15 (first link). The rotation sensor 40E detects the rotation of the rotating part 50E fixed to the link 16 (second link) relative to the link 15 (first link). The rotation sensor 40F is fixed to the link 16 (first link). The rotation sensor 40F detects the rotation of the rotating part 50F fixed to the link 17 (second link) relative to the link 16 (first link).

[0025] The rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F and the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F may be configured to output detection results in a common data format. For example, the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F and the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F may be configured to transmit the detection results, expressed in a common data format, to the robot controller 3 using a common communication protocol.

[0026] Hereinafter, unless there is a need to distinguish between them, each of the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F will be referred to as a rotation sensor 40, each of the rotating units 50A, 50B, 50C, 50D, 50E, and 50F will be referred to as a rotating unit 50, and each of the joint axes Ax1, Ax2, Ax3, Ax4, Ax5, and Ax6 will be referred to as a joint axis Ax. As described above, the rotation sensor 40 is fixed to the first link, and the rotating unit 50 is fixed to the second link. Therefore, the position of the rotating unit 50 relative to the rotation sensor 40 may be shifted due to, for example, bending of the second link relative to the first link. In response to this, the robot 2 may have a holding member 70 for at least one of the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F. The holding member 70 is fixed to the first link to hold the rotation sensor 40, and holds the rotating part 50 so that it can rotate around the joint axis Ax.

[0027] Both the rotation sensor 40 and the rotating part 50 are held by the holding member 70. Therefore, even if the second link bends relative to the first link, eccentricity, angular misalignment, etc. of the rotating part 50 relative to the rotation sensor 40 is suppressed. This improves the accuracy of rotation detection by the rotation sensor 40.

[0028] Holding the rotating unit 50 so that it can rotate about the joint axis Ax means allowing the rotating unit 50 to rotate about the joint axis Ax while restricting displacement of the rotating unit 50 in a direction intersecting the joint axis Ax. The holding member 70 may be fixed directly to the first link, or may be fixed indirectly via another member.

[0029] As an example, the robot 2 has a holding member 70 for each of the rotation sensors 40A, 40B, 40C, 40D, and 40E. The peripheral structure of each of the rotation sensors 40A, 40B, 40C, and 40E will be described individually below. The peripheral structure of the rotation sensor 40D is similar to that of the rotation sensor 40A, so a description thereof will be omitted.

[0030] [Peripheral structure of rotation sensor 40A] As shown in FIG. 2, the robot 2 further includes a reducer 60A (reduction gear 60). The reducer 60A transmits the rotation of the motor 20A (rotation of the output shaft 21) to the link 11 so as to rotate the link 11 around the joint axis Ax1 relative to the link 12. The motor 20A is connected to the link 12 from one side in the direction along the joint axis Ax1 (e.g., from above) at a position away from the joint axis Ax1. The link 11 is connected to the reducer 60A from the other side in the direction along the joint axis Ax1 (e.g., from below). The rotating part 50A is a shaft that penetrates the reducer 60A and protrudes from the link 11 toward the link 12. The holding member 70A is fixed to the link 12 from above to hold the rotation sensor 40A, and is attached to the reducer 60A from above.

[0031] For example, the reducer 60A has an input shaft 61 and an output shaft 62, and is fixed to the link 12. The input shaft 61 rotates relative to the link 12 around a rotation axis parallel to the joint axis Ax1. The output shaft 62 protrudes downward and is fixed to the link 11, and rotates relative to the link 12 around the joint axis Ax1. The reducer 60A is configured to reduce the rotation of the input shaft 61 and transmit it to the output shaft 62.

[0032] The motor 20A is fixed to the link 12 with its output shaft 21 facing downward. The output shaft 21 of the motor 20A is fixed to the input shaft 61 of the reducer 60A. This causes the rotation of the output shaft 21 to be transmitted to the link 11. For example, the input shaft 61 rotates together with the output shaft 21, and the rotation of the input shaft 61 is transmitted to the output shaft 62, causing the link 11 to rotate together with the output shaft 62 relative to the link 12. The reducer 60A, including the output shaft 62, is hollow in the direction along the joint axis Ax1, and the rotating part 50A protrudes from the link 11 toward the link 12 via the inside of the output shaft 62.

[0033] The rotating part 50A has a first end 51 and a second end 52 arranged in this order from the tip (upper end). The outer diameter of the first end 51 is smaller than the outer diameter of a portion adjacent to the first end 51 on the link 11 side. The outer diameter of the second end 52 is smaller than the outer diameter of a portion adjacent to the second end 52 on the link 11 side.

[0034] The rotation sensor 40A has a sensor body 41, a sensor shaft 42, a sensor bearing 43, a code disk 44, and a detection unit 45. The sensor body 41 is held by a holding member 70A. For example, the sensor body 41 is fixed to the holding member 70A from above.

[0035] The sensor shaft 42 rotates relative to the sensor main body 41 around the joint axis Ax1. The sensor shaft 42 is held by the sensor main body 41 so as to be rotatable around the joint axis Ax1 within the sensor main body 41. For example, the sensor main body 41 holds the sensor shaft 42 via a sensor bearing 43. The sensor bearing 43 may be a rolling bearing or a sliding bearing. The sensor shaft 42 protrudes downward from the sensor main body 41. The detection unit 45 is housed within the sensor main body 41 and detects the rotation of the sensor shaft 42 relative to the sensor main body 41.

[0036] For example, the sensor main body 41 has a code disk 44. The code disk 44 protrudes in a direction away from the outer circumferential surface of the sensor shaft 42 over the entire circumference (the entire circumference around the joint axis Ax1) and rotates together with the sensor shaft 42. The code disk 44 has a code track along the circumferential direction around the joint axis Ax. The detection unit 45 is fixed in the sensor main body 41 so as to face the code track of the code disk 44. The code track passes through the detection unit 45 as the code disk 44 rotates. The detection unit 45 generates a signal in response to the passage of the code track.

[0037] The holding member 70A to which the rotation sensor 40A is fixed is fixed to the link 12 and holds the rotating part 50A so that it can rotate around the joint axis Ax1. For example, the holding member 70A is directly fixed to the link 12 from above. For example, the holding member 70A is fixed to the link 12 in a detachable manner by bolting or the like. When fixed to the link 12 from above, the holding member 70A is attached to the rotating part 50A from above.

[0038] Holding member 70A may hold rotating part 50A via bearing 71. For example, holding member 70A holds second end 52 of rotating part 50A from the outer periphery via bearing 71. Bearing 71 may be a rolling bearing or a sliding bearing.

[0039] For example, the holding member 70A has a body holding portion 72 and a shaft holding portion 73. The body holding portion 72 holds the sensor body 41. For example, the body holding portion 72 extends along a plane intersecting (for example, perpendicular to) the joint axis Ax1. The sensor body 41 is fixed to the body holding portion 72 from above. For example, the sensor body 41 is fixed to the body holding portion 72 in a detachable manner by bolting or the like. The sensor shaft 42 protruding downward from the sensor body 41 penetrates the body holding portion 72 and protrudes downward beyond the body holding portion 72.

[0040] The shaft holding part 73 protrudes downward from the main body holding part 72 and surrounds the second end part 52 around the joint axis Ax1 to hold the rotating part 50A. The outer periphery of the main body holding part 72 around the joint axis Ax1 and the inner periphery and outer periphery of the shaft holding part 73 around the joint axis Ax1 may be circular and concentric with each other.

[0041] The robot 2 may further include a joint member 80A (joint member 80). The joint member 80A connects the rotating part 50A to the sensor shaft 42. The joint member 80A may connect the rotating part 50A to the sensor shaft 42 inside the shaft holding part 73. For example, the joint member 80A is housed inside the shaft holding part 73 and connects the first end 51 of the rotating part 50A to the sensor shaft 42.

[0042] The coupling member 80A may be configured to couple the rotating part 50A held by the holding member 70A to the sensor shaft 42 while absorbing misalignment between the rotating part 50A and the sensor shaft 42. Examples of such coupling members 80A include Oldham couplings, bellows couplings, and slit couplings. An Oldham coupling is a coupling that connects two semicircular disks with an intermediate piece having orthogonal sliding tracks, allowing for misalignment of the axes parallel to each other. A bellows coupling connects two shafts via a corrugated metal bellows, absorbing axial misalignment and angular displacement. A slit coupling is a coupling with a cylindrical body having multiple slits, which provides elasticity and absorbs axial misalignment.

[0043] The robot 2 may further include a position adjustment part PA1 (position adjustment part PA). The position adjustment part PA1 makes it possible to adjust the position of the holding member 70A relative to the link 12. For example, the link 12 may have an opening H1 through which the shaft holding part 73 passes from above to below, and the inner diameter of the opening H1 may be larger than the outer diameter of the shaft holding part 73. As a result, the position adjustment part PA1 is formed between the inner periphery of the opening H1 and the outer periphery of the shaft holding part 73.

[0044] [Peripheral structure of rotation sensor 40B] 3, the robot 2 further includes a reducer 60B (reduction gear 60). The reducer 60B transmits the rotation of the motor 20B (rotation of the output shaft 21) to the link 13 so as to rotate the link 13 around the joint axis Ax2 relative to the link 12.

[0045] The motor 20B is connected to the link 12 from one side in the direction along the joint axis Ax2 (the right side in the drawing). The link 13 is connected to the output shaft 62 of the reducer 60B from the other side in the direction along the joint axis Ax2 (the left side in the drawing). The holding member 70B is attached to the rotating part 50B from the other side.

[0046] For example, the link 12 has a pivot base 12a and a protrusion 12b. The pivot base 12a extends along a plane that intersects (for example, is perpendicular to) the joint axis Ax1. The protrusion 12b protrudes upward from the pivot base 12a.

[0047] The reducer 60B has an input shaft 61 and an output shaft 62, and is fixed to the protruding portion 12b from the other side. The input shaft 61 rotates around the joint axis Ax2 relative to the protruding portion 12b. The output shaft 62 protrudes from the other side and is fixed to the link 13, and rotates around the joint axis Ax2 relative to the protruding portion 12b. The reducer 60B is configured to reduce the rotation of the input shaft 61 and transmit it to the output shaft 62.

[0048] The motor 20B is fixed to the protruding portion 12b from the one side with the output shaft 21 facing the other side. The output shaft 21 of the motor 20B is fixed to the input shaft 61 of the reducer 60B. As a result, the rotation of the output shaft 21 is transmitted to the link 13.

[0049] The rotating part 50B is a shaft that protrudes from the link 13 to the other side (left side in the drawing) along the joint axis Ax2. The rotating part 50B has a first end 51 and a second end 52 that are arranged in this order from the tip (left end in the drawing). The outer diameter of the first end 51 is smaller than the outer diameter of a portion adjacent to the first end 51 on the link 13 side. The outer diameter of the second end 52 is smaller than the outer diameter of a portion adjacent to the second end 52 on the link 13 side.

[0050] The rotation sensor 40B has the same configuration as the rotation sensor 40A, and includes a sensor body 41, a sensor shaft 42, a sensor bearing 43, a code disk 44, and a detection unit 45. The sensor body 41 is held by a holding member 70B. For example, the sensor body 41 is fixed to the holding member 70B from the other side. The sensor shaft 42 rotates relative to the sensor body 41 around the joint axis Ax2. The sensor shaft 42 protrudes from the sensor body 41 toward the one side.

[0051] A holding member 70B to which the rotation sensor 40B is fixed is fixed to the link 12 and holds the rotating part 50B so that it can rotate around the joint axis Ax2. The holding member 70B is attached to the rotating part 50B from the other side.

[0052] The holding member 70B may hold the rotating part 50B via a bearing 71. For example, the holding member 70B holds the second end 52 of the rotating part 50B from the outer periphery via the bearing 71. The bearing 71 may be a rolling bearing or a plain bearing.

[0053] For example, the holding member 70B has a body holding portion 72 and a shaft holding portion 73, similar to the holding member 70A. The body holding portion 72 holds the sensor body 41. For example, the body holding portion 72 extends along a plane intersecting (for example, perpendicular to) the joint axis Ax2. The sensor body 41 is fixed to the body holding portion 72 from the other side. For example, the sensor body 41 is fixed to the body holding portion 72 in a detachable manner by bolting or the like. The sensor shaft 42 protruding from the sensor body 41 to the one side passes through the body holding portion 72 and protrudes beyond the body holding portion 72 to the one side.

[0054] The shaft holding part 73 protrudes from the main body holding part 72 to the one side and surrounds the second end part 52 around the joint axis Ax2 to hold the rotating part 50B. The outer periphery of the main body holding part 72 around the joint axis Ax2 and the inner periphery and outer periphery of the shaft holding part 73 around the joint axis Ax2 may be circular and concentric with each other.

[0055] The robot 2 may further include a joint member 80B (joint member 80). The joint member 80B connects the rotating part 50B to the sensor shaft 42. The joint member 80B may connect the rotating part 50B to the sensor shaft 42 inside the shaft holding part 73. For example, the joint member 80B is housed inside the shaft holding part 73 and connects the first end 51 of the rotating part 50B to the sensor shaft 42.

[0056] The coupling member 80B may be configured to couple the rotating part 50B to the sensor shaft 42 while absorbing any positional misalignment between the rotating part 50B held by the holding member 70B and the sensor shaft 42. As described above, examples of such a coupling member 80B include an Oldham type coupling, a bellows type coupling, and a slit type coupling.

[0057] While the holding member 70A is directly fixed to the link 12, the holding member 70B is indirectly fixed to the link 12. For example, the robot 2 further includes a bridge member 90B (bridge member 90), and the holding member 70B is fixed to the link 12 via the bridge member 90B.

[0058] The bridge member 90B is separate from the holding member 70B, and is fixed to the holding member 70B so as to extend away from the joint axis Ax2, and is then fixed to the link 12. The bridge member 90B extends from the holding member 70B away from the joint axis Ax2, and is fixed to the link 12 outward of the outer periphery of the link 13 around the joint axis Ax2. For example, the bridge member 90B extends downward from the holding member 70B and is fixed to the swivel base 12a.

[0059] For example, the bridge member 90B has a bridge plate 91 and a bracket 92. The bridge plate 91 extends along a plane intersecting (for example, perpendicular to) the joint axis Ax2 and downward from the holding member 70B. The bracket 92 projects from the lower end of the bridge plate 91 toward the other side so as to fit along the upper surface of the swivel base 12a. The bracket 92 is removably fixed to the swivel base 12a by bolting or the like.

[0060] The bridge plate 91 is fixed to the main body holding portion 72 of the holding member 70B from the other side. For example, the bridge plate 91 has a sensor opening 93 through which the rotation sensor 40B, which is fixed to the main body holding portion 72 from the other side, passes from the one side to the other side. Around the rotation sensor 40B that has passed through the sensor opening 93, the bridge plate 91 is removably fixed to the main body holding portion 72 by bolting or the like.

[0061] The robot 2 may further include a position adjustment part PA2 (position adjustment part PA). The position adjustment part PA2 makes it possible to adjust the position of the holding member 70B relative to the link 12. The position adjustment part PA2 may be provided on the bridge member 90B so as to make it possible to adjust the position of the holding member 70B relative to the bridge member 90B. For example, the inner diameter of the sensor opening 93 may be larger than the outer diameter of the sensor main body 41. This forms the position adjustment part PA2 between the inner periphery of the sensor opening 93 and the outer periphery of the sensor main body 41.

[0062] The rotation sensor 40B may further include a cable 46, and the bridge member 90B may further include a cable guide 94. The cable 46 is routed from the sensor body 41 to the link 12 and transmits a signal generated by the rotation sensor 40B. The cable guide 94 guides the cable 46 from the sensor body 41 to the link 12 along the bridge member 90B.

[0063] The bridge plate 91 of the bridge member 90B has a first surface 91a facing the link 13 and a second surface 91b opposite the first surface 91a. The cable guide 94 may be configured to guide the cable 46 along the second surface 91b. For example, the cable guide 94 may be a clip that protrudes from the second surface 91b and holds the cable 46. The cable guide 94 may also be a groove that is formed in the bridge plate 91 so as to be recessed from the second surface 91b and that accommodates the cable 46.

[0064] [Peripheral structure of rotation sensor 40C] 4, the robot 2 further includes a reducer 60C (reduction gear 60). The reducer 60C transmits the rotation of the motor 20C (rotation of the output shaft 21) to the link 13 so as to rotate the link 13 around the joint axis Ax3 relative to the link 14.

[0065] The motor 20C is connected to the link 14 from one side in the direction along the joint axis Ax3 (the right side in the drawing). The link 13 is connected to the reducer 60C from the other side in the direction along the joint axis Ax3 (the left side in the drawing). The holding member 70C is attached to the rotating part 50C from the other side.

[0066] The reducer 60C has an input shaft 61 and an output shaft 62, and is fixed to the link 14 from the other side. The input shaft 61 rotates around the joint axis Ax3 relative to the link 14. The output shaft 62 protrudes to the other side and is fixed to the link 13, and rotates around the joint axis Ax3 relative to the link 14. The reducer 60C is configured to reduce the rotation of the input shaft 61 and transmit it to the output shaft 62.

[0067] The motor 20C is fixed to the link 14 from the one side with the output shaft 21 facing the other side. The output shaft 21 of the motor 20C is fixed to the input shaft 61 of the reducer 60C. As a result, the rotation of the output shaft 21 is transmitted to the link 13.

[0068] The rotating part 50C is a shaft that protrudes from the link 13 to the other side (left side in the drawing) along the joint axis Ax3. The rotating part 50C has a first end 51 and a second end 52 that are arranged in this order from the tip (left end in the drawing). The outer diameter of the first end 51 is smaller than the outer diameter of a portion adjacent to the first end 51 on the link 13 side. The outer diameter of the second end 52 is smaller than the outer diameter of a portion adjacent to the second end 52 on the link 13 side.

[0069] The rotation sensor 40C has the same configuration as the rotation sensor 40A, and includes a sensor body 41, a sensor shaft 42, a sensor bearing 43, a code disk 44, and a detection unit 45. The sensor body 41 is held by a holding member 70C. For example, the sensor body 41 is fixed to the holding member 70C from the other side. The sensor shaft 42 rotates relative to the sensor body 41 around the joint axis Ax3. The sensor shaft 42 protrudes from the sensor body 41 toward the one side.

[0070] A holding member 70C to which the rotation sensor 40C is fixed is fixed to the link 14 and holds the rotating part 50C so that it can rotate around the joint axis Ax3. The holding member 70C is attached to the rotating part 50C from the other side.

[0071] The holding member 70C may hold the rotating part 50C via a bearing 71. For example, the holding member 70C holds the second end 52 of the rotating part 50C from the outer periphery via the bearing 71. The bearing 71 may be a rolling bearing or a plain bearing.

[0072] For example, the holding member 70C has a body holding portion 72 and a shaft holding portion 73, similar to the holding member 70A. The body holding portion 72 holds the sensor body 41. For example, the body holding portion 72 extends along a plane intersecting (for example, perpendicular to) the joint axis Ax3. The sensor body 41 is fixed to the body holding portion 72 from the other side. For example, the sensor body 41 is fixed to the body holding portion 72 in a detachable manner by bolting or the like. The sensor shaft 42 protruding from the sensor body 41 to the one side passes through the body holding portion 72 and protrudes beyond the body holding portion 72 to the one side.

[0073] The shaft holding portion 73 protrudes from the main body holding portion 72 to the one side and surrounds the second end portion 52 around the joint axis Ax3 to hold the rotating portion 50C. The outer periphery of the main body holding portion 72 around the joint axis Ax3 and the inner and outer peripheries of the shaft holding portion 73 around the joint axis Ax3 may be circular and concentric with each other.

[0074] The robot 2 may further include a joint member 80C (joint member 80). The joint member 80C connects the rotating part 50C to the sensor shaft 42. The joint member 80C may connect the rotating part 50C to the sensor shaft 42 inside the shaft holding part 73. For example, the joint member 80C is housed inside the shaft holding part 73 and connects the first end 51 of the rotating part 50C to the sensor shaft 42.

[0075] The coupling member 80C may be configured to couple the rotating part 50C to the sensor shaft 42 while absorbing any positional misalignment between the rotating part 50C held by the holding member 70C and the sensor shaft 42. As described above, examples of such a coupling member 80C include an Oldham coupling, a bellows coupling, and a slit coupling.

[0076] Just as the holding member 70B is indirectly fixed to the link 12, the holding member 70C is indirectly fixed to the link 14. For example, the robot 2 further includes a bridge member 90C (bridge member 90) and a support member 95, and the holding member 70C is fixed to the link 14 via the bridge member 90C and the support member 95.

[0077] The support member 95 protrudes from the link 14 toward the other side, outward from the outer periphery of the link 13 about the joint axis Ax3. The support member 95 is separate from the link 14 and is detachably fixed to the link 14 by, for example, bolting. The support member 95 may also be molded integrally with the link 14.

[0078] The bridge member 90C is separate from the holding member 70C and the support member 95, and is fixed to the holding member 70C so as to extend away from the joint axis Ax3, and is fixed to the link 14 via the support member 95. The bridge member 90C extends from the holding member 70C away from the joint axis Ax3, and is fixed to the support member 95 outward from the outer periphery of the link 13 around the joint axis Ax3.

[0079] For example, the bridge member 90C extends along a plane intersecting (e.g., perpendicular to) the joint axis Ax3 and extends from the retaining member 70C away from the joint axis Ax3. The bridge member 90C has a first connection surface 96 and a second connection surface 97. The first connection surface 96 and the second connection surface 97 face the same direction (e.g., the above one side) in the direction along the joint axis Ax3.

[0080] The bridge member 90C is fixed to the link 14 so that the first connection surface 96 contacts the link 14. The support member 95 constitutes a part of the link 14 by being fixed to the link 14 as described above. Therefore, fixing the bridge member 90C to the link 14 so that the first connection surface 96 contacts the link 14 includes fixing the bridge member 90C to the support member 95 so that the first connection surface 96 contacts the support member 95.

[0081] The bridge member 90C is fixed to the body holding portion 72 from the other side so that the second connection surface 97 contacts the body holding portion 72 of the holding member 70B. For example, the bridge member 90C has a sensor opening 93 through which the rotation sensor 40C, fixed to the body holding portion 72 from the other side, passes from the one side to the other side. Around the rotation sensor 40C passed through the sensor opening 93, the bridge member 90C is removably fixed to the body holding portion 72 by bolting or the like.

[0082] The robot 2 may further include a position adjustment unit PA3 (position adjustment unit PA). The position adjustment unit PA3 makes it possible to adjust the position of the holding member 70C relative to the link 14. The position adjustment unit PA3 may be provided on the bridge member 90C so as to make it possible to adjust the position of the holding member 70C relative to the bridge member 90C. For example, the inner diameter of the sensor opening 93 may be larger than the outer diameter of the sensor main body 41. This forms the position adjustment unit PA3 between the inner periphery of the sensor opening 93 and the outer periphery of the sensor main body 41.

[0083] The rotation sensor 40C may further include a cable 46, and the bridge member 90C may further include a cable guide 94. The cable 46 is routed from the sensor body 41 to the link 14 and transmits a signal generated by the rotation sensor 40C. The cable guide 94 guides the cable 46 from the sensor body 41 to the link 14 along the bridge member 90C.

[0084] The bridge plate 91 of the bridge member 90C has a first surface 91a facing the link 13 and a second surface 91b opposite the first surface 91a. The cable guide 94 may be configured to guide the cable 46 along the second surface 91b. For example, the cable guide 94 may be a clip that protrudes from the second surface 91b and holds the cable 46. The cable guide 94 may also be a groove that is formed in the bridge plate 91 so as to be recessed from the second surface 91b and that accommodates the cable 46.

[0085] [Peripheral structure of rotation sensor 40E] 5, the robot 2 further includes a reducer 60E (reduction gear 60). The reducer 60E transmits the rotation of the motor 20E (rotation of the output shaft 21) to the link 16 so as to rotate the link 16 around the joint axis Ax5 relative to the link 15.

[0086] The motor 20E is connected to the link 15 from one side (the upper side in the drawing) in the direction along the joint axis Ax5 at a position away from the joint axis Ax5. The link 16 is connected to the reducer 60E from the one side. The holding member 70E is attached to the rotating part 50E from the one side.

[0087] The reducer 60E has an input shaft 61 and an output shaft 62, and is fixed to the link 15 from the other side in the direction along the joint axis Ax5 (below in the figure). The input shaft 61 protrudes to the other side and rotates around the joint axis Ax5 with respect to the link 15. The output shaft 62 protrudes to the one side, passes through the link 15 and is fixed to the link 16, and rotates around the joint axis Ax5 with respect to the link 15. The reducer 60E is configured to reduce the rotation of the input shaft 61 and transmit it to the output shaft 62.

[0088] The motor 20E is fixed to the link 15 from the one side with its output shaft 21 facing the other side. The output shaft 21 of the motor 20E passes through the link 15 and protrudes to the other side. The robot 2 further includes a pulley 22, a pulley 63, and a belt 64. The pulley 22 is fixed to the outer periphery of the output shaft 21 protruding to the other side. The pulley 63 is fixed to the outer periphery of the input shaft 61 protruding to the other side. The belt 64 is looped around the outer periphery of the pulley 22 and the pulley 63 so as to form a loop around the joint axis Ax5, and transmits rotation from the pulley 22 to the pulley 63. As a result, the rotation of the output shaft 21 is transmitted to the link 16. For example, the belt 64 transmits rotation from the output shaft 21 to the input shaft 61, and the reducer 60E transmits rotation from the input shaft 61 to the link 16. The element for transmitting rotation from the output shaft 21 to the input shaft 61 is not limited to the belt 64. The robot 2 may have a plurality of gears that transmit rotation from the output shaft 21 to the input shaft 61, instead of the pulley 22, the pulley 63, and the belt 64.

[0089] The rotating part 50E is a shaft that protrudes from the link 16 to one side (the top in the illustration) along the joint axis Ax5. The rotating part 50E has a first end 51 and a second end 52 that are arranged in this order from the tip (the left end in the illustration). The outer diameter of the first end 51 is smaller than the outer diameter of a portion adjacent to the first end 51 on the link 11 side. The outer diameter of the second end 52 is smaller than the outer diameter of a portion adjacent to the second end 52 on the link 11 side.

[0090] The rotation sensor 40E has the same configuration as the rotation sensor 40A, and includes a sensor body 41, a sensor shaft 42, a sensor bearing 43, a code disk 44, and a detection unit 45. The sensor body 41 is held by a holding member 70E. For example, the sensor body 41 is fixed to the holding member 70E from one side. The sensor shaft 42 rotates around the joint axis Ax5 relative to the sensor body 41. The sensor shaft 42 protrudes from the sensor body 41 toward the other side.

[0091] A holding member 70E to which the rotation sensor 40E is fixed is fixed to the link 15, and holds the rotating part 50E so as to be rotatable around the joint axis Ax5. The holding member 70E is attached to the rotating part 50E from one of the above-mentioned sides.

[0092] Holding member 70E may hold rotating part 50E via bearing 71. For example, holding member 70E holds second end 52 of rotating part 50E from the outer periphery via bearing 71. Bearing 71 may be a rolling bearing or a plain bearing.

[0093] For example, the holding member 70E has a body holding portion 72 and a shaft holding portion 73, similar to the holding member 70A. The body holding portion 72 holds the sensor body 41. For example, the body holding portion 72 extends along a plane intersecting (for example, perpendicular to) the joint axis Ax5. The sensor body 41 is fixed to the body holding portion 72 from the one side. For example, the sensor body 41 is fixed to the body holding portion 72 in a detachable manner by bolting or the like. The sensor shaft 42 protruding from the sensor body 41 to the other side passes through the body holding portion 72 and protrudes beyond the body holding portion 72 to the other side.

[0094] The shaft holding portion 73 protrudes from the main body holding portion 72 to the other side, surrounds the second end portion 52 around the joint axis Ax5, and holds the rotating portion 50E. The outer periphery of the main body holding portion 72 around the joint axis Ax5 and the inner and outer peripheries of the shaft holding portion 73 around the joint axis Ax5 may be circular and concentric with each other.

[0095] The robot 2 may further include a joint member 80E (joint member 80). The joint member 80E connects the rotating part 50E to the sensor shaft 42. The joint member 80E may connect the rotating part 50E to the sensor shaft 42 inside the shaft holding part 73. For example, the joint member 80E is housed inside the shaft holding part 73 and connects the first end 51 of the rotating part 50E to the sensor shaft 42.

[0096] The coupling member 80E may be configured to couple the rotating part 50E to the sensor shaft 42 while absorbing any positional misalignment between the rotating part 50E held by the holding member 70E and the sensor shaft 42. As described above, examples of such a coupling member 80E include an Oldham coupling, a bellows coupling, and a slit coupling.

[0097] Just as the holding member 70B is indirectly fixed to the link 12, the holding member 70E is indirectly fixed to the link 15. For example, the robot 2 further includes a bridge member 90E (bridge member 90) and a support member 95, and the holding member 70E is fixed to the link 15 via the bridge member 90E and the support member 95.

[0098] The support member 95 protrudes from the link 15 toward the one side, outward from the outer periphery of the link 16 around the joint axis Ax5. The support member 95 is separate from the link 15 and is detachably fixed to the link 15 by, for example, bolting. The support member 95 may also be molded integrally with the link 15.

[0099] The bridge member 90E is separate from the holding member 70E and the support member 95, and is fixed to the holding member 70E so as to extend away from the joint axis Ax5, and is fixed to the link 15 via the support member 95. The bridge member 90E extends from the holding member 70E away from the joint axis Ax5, and is fixed to the support member 95 outward from the outer periphery of the link 16 around the joint axis Ax5.

[0100] For example, the bridge member 90E extends along a plane intersecting (e.g., perpendicular to) the joint axis Ax5 and extends from the retaining member 70E away from the joint axis Ax5. The bridge member 90E has a first connecting surface 96 and a second connecting surface 97. The first connecting surface 96 and the second connecting surface 97 face the same direction (e.g., the other direction) in the direction along the joint axis Ax5.

[0101] The bridge member 90E is fixed to the link 15 so that the first connection surface 96 contacts the link 15. The support member 95 constitutes a part of the link 15 by being fixed to the link 15 as described above. Therefore, fixing the bridge member 90E to the link 15 so that the first connection surface 96 contacts the link 15 includes fixing the bridge member 90E to the support member 95 so that the first connection surface 96 contacts the support member 95.

[0102] The bridge member 90E is fixed to the body holding portion 72 from the one side so that the second connection surface 97 contacts the body holding portion 72 of the holding member 70E. For example, the bridge member 90E has a sensor opening 93 through which the rotation sensor 40E, fixed to the body holding portion 72 from the one side, passes from the other side to the one side. Around the rotation sensor 40E passed through the sensor opening 93, the bridge member 90E is removably fixed to the body holding portion 72 by bolting or the like.

[0103] The robot 2 may further include a position adjustment unit PA5 (position adjustment unit PA). The position adjustment unit PA5 makes it possible to adjust the position of the holding member 70E relative to the link 15. The position adjustment unit PA5 may be provided on the bridge member 90E so as to make it possible to adjust the position of the holding member 70E relative to the bridge member 90E. For example, the inner diameter of the sensor opening 93 may be larger than the outer diameter of the sensor main body 41. This forms the position adjustment unit PA5 between the inner periphery of the sensor opening 93 and the outer periphery of the sensor main body 41.

[0104] The rotation sensor 40E may further include a cable 46, and the bridge member 90E may further include a cable guide 94. The cable 46 is routed from the sensor body 41 to the link 15 and transmits a signal generated by the rotation sensor 40E. The cable guide 94 guides the cable 46 from the sensor body 41 to the link 15 along the bridge member 90E.

[0105] The bridge plate 91 of the bridge member 90E has a first surface 91a facing the link 16 and a second surface 91b opposite the first surface 91a. The cable guide 94 may be configured to guide the cable 46 along the second surface 91b. For example, the cable guide 94 may be a clip that protrudes from the second surface 91b and holds the cable 46. The cable guide 94 may also be a groove that is formed in the bridge plate 91 so as to be recessed from the second surface 91b and that accommodates the cable 46.

[0106] [Communication between the rotation sensor and the robot controller] Of the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F, at least the rotation sensors 40 of the robot 2 may be configured so that one rotation sensor 40 (second rotation sensor) transmits its detection result to the other rotation sensor 40 via serial communication, and the other rotation sensor 40 transmits its own detection result and the detection result of the one rotation sensor 40 via serial communication.

[0107] 6, each of the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F may have a lower port 47 and an upper port 48, and may be configured to receive data at the lower port 47 and transmit the received data and its own detection results from the upper port 48. As an example, FIG. 6 shows a state in which the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F are serially connected to the robot controller 3 by cables 46A, 46B, 46C, 46D, 46E, and 46F using the lower port 47 and the upper port 48.

[0108] As shown in FIG. 6 , cable 46F connects the upper port 48 of rotation sensor 40F to the lower port 47 of rotation sensor 40E. Cable 46E connects the upper port 48 of rotation sensor 40E to the lower port 47 of rotation sensor 40D. Cable 46D connects the upper port 48 of rotation sensor 40D to the lower port 47 of rotation sensor 40C. Cable 46C connects the upper port 48 of rotation sensor 40C to the lower port 47 of rotation sensor 40B. Cable 46B connects the upper port 48 of rotation sensor 40B to the lower port 47 of rotation sensor 40A. Cable 46A connects the upper port 48 of rotation sensor 40A to the robot controller 3.

[0109] In this connection, rotation sensor 40F transmits its own detection result to rotation sensor 40E. Rotation sensor 40E transmits its own detection result and the detection result by rotation sensor 40F to rotation sensor 40D. Rotation sensor 40D transmits its own detection result and the detection results by rotation sensors 40E and 40F to rotation sensor 40C. Rotation sensor 40C transmits its own detection result and the detection results by rotation sensors 40D, 40E, and 40F to rotation sensor 40B. Rotation sensor 40B transmits its own detection result and the detection results by rotation sensors 40C, 40D, 40E, and 40F to rotation sensor 40A. Rotation sensor 40A transmits its own detection result and the detection results by rotation sensors 40B, 40C, 40D, 40E, and 40F to the robot controller 3. In this way, all of the detection results of the rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F can be transmitted to the robot controller 3 via the series of cables 46A, 46B, 46C, 46D, 46E, and 46F.

[0110] Similarly, among the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F, at least the motor rotation sensors 30 of the robot 2 may be configured so that one motor rotation sensor 30 (second motor rotation sensor) transmits its detection result to the other motor rotation sensor 30 via serial communication, and the other motor rotation sensor 30 transmits its own detection result and the detection result of the one motor rotation sensor 30 via serial communication.

[0111] For example, as shown in FIG. 7 , each of the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F may have an upper port 37 and a lower port 38, and may be configured to receive data at the upper port 37 and transmit the received data and its own detection results from the lower port 38. As an example, FIG. 7 shows a state in which the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F are serially connected to the robot controller 3 via cables 36A, 36B, 36C, 36D, 36E, and 36F using the upper port 37 and the lower port 38. As in the example of FIG. 6 , all of the detection results of the motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F can be transmitted to the robot controller 3 via the series of cables 36A, 36B, 36C, 36D, 36E, and 36F.

[0112] 6 and 7 illustrate an example in which rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F and motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F are assigned to two communication systems, but the assignment method is not limited to this example. For example, at least one of rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F and at least one of motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F may be mixed in a single communication system. Furthermore, all of rotation sensors 40A, 40B, 40C, 40D, 40E, and 40F and all of motor rotation sensors 30A, 30B, 30C, 30D, 30E, and 30F may be combined into a single communication system.

[0113] 〔summary〕 The above-described exemplary embodiment includes the following configurations. (1) A robot 2 comprising a first link and a second link connected to each other at a joint axis Ax, a rotating part 50 fixed to the second link and rotating around the joint axis Ax relative to the first link, a rotation sensor 40 held by a holding member 70 and detecting rotation of the rotating part 50, and a holding member 70 fixed to the first link, holding the rotation sensor 40, and holding the rotating part 50 so that it can rotate around the joint axis Ax. Because the rotation sensor 40 is fixed to the first link, it can directly detect the rotation angle (joint angle) of the second link relative to the first link. Because the rotation sensor 40 is fixed to the first link and the rotating unit 50 is fixed to the second link, deflection of the second link relative to the first link, etc., can cause the rotating unit 50 to shift position relative to the rotation sensor 40. According to this robot 2, both the rotation sensor 40 and the rotating unit 50 are held by a holding member 70 fixed to the first link. Therefore, even if deflection of the second link relative to the first link occurs, eccentricity, angular deviation, etc. of the rotating unit 50 relative to the rotation sensor 40 are suppressed. This is therefore effective in improving the accuracy of rotation detection by the rotation sensor 40.

[0114] (2) The robot 2 described in (1), wherein the rotating part 50 is a shaft that protrudes from the second link toward the rotation sensor 40, and the holding member 70 holds the shaft via a bearing 71. The shaft can be rotated more smoothly while being held in place.

[0115] (3) The robot 2 according to (1) or (2), further comprising a position adjustment part PA that makes it possible to adjust the position of the holding member 70 relative to the first link. As described above, by the holding member 70 holding both the rotation sensor 40 and the rotating unit 50, eccentricity, angular misalignment, etc. of the rotating unit 50 relative to the rotation sensor 40 is reduced, while the position of the holding member 70 is constrained to the position of the rotating unit 50. For this reason, holding the rotating unit 50 on the mount member can cause the holding member 70 to shift in position relative to the first link. This positional deviation can be easily absorbed by the position adjustment unit PA.

[0116] (4) The robot 2 described in any one of (1) to (3) further includes a bridge member 90 that is separate from the holding member 70, is fixed to the holding member 70 so as to extend away from the joint axis Ax, and is fixed to the first link. This allows for a simplified structure of the holding member 70 while improving the degree of freedom in arranging the holding member 70.

[0117] (5) The robot (2) described in (4) further includes a cable routed from the rotation sensor (40) to the first link, and a cable guide (94) that guides the cable along the bridge member (90). A bridge member 90 can be used to stabilize the cable routing to the first link.

[0118] (6) The robot 2 described in (5) above, wherein the bridge member 90 has a first surface 91a facing the second link and a second surface 91b opposite the first surface 91a, and the cable guide 94 guides the cable along the second surface 91b. The cable routing can be away from the second link that moves relative to the body.

[0119] (7) A robot 2 described in any one of (4) to (6), wherein the bridge member 90 has a first connection surface 96 and a second connection surface 97 facing in the same direction in the direction along the joint axis Ax, and the first connection surface 96 is fixed to the first link so as to contact the first link, and the second connection surface 97 is fixed to the holding member 70 so as to contact the holding member 70. Because the first connection surface 96 that contacts the first link and the second connection surface 97 that is fixed to the retaining member 70 face in the same direction, the relative positional accuracy of the second connection surface 97 with respect to the first connection surface 96 can be improved, and the positioning accuracy of the retaining member 70 with respect to the first link can be improved. The ease of processing the first connection surface 96 and the second connection surface 97 also contributes to reducing the processing costs of the bridge member 90.

[0120] (8) A robot 2 according to any one of (1) to (7), wherein the rotating part 50 is a shaft protruding from the second link toward the rotation sensor 40, the rotation sensor 40 has a sensor main body 41 held by a holding member 70, a sensor shaft 42 that rotates relative to the sensor main body 41 around the joint axis Ax, and a detection part 45 that detects the rotation of the sensor shaft 42 relative to the sensor main body 41, and the robot 2 further includes a coupling member 80 that connects the shaft to the sensor shaft 42. Combining the sensor main body 41, shaft, and detection unit 45 into one unit simplifies the structure of the robot 2. The holding member 70 holds both the sensor main body 41 and the shaft, thereby suppressing eccentricity, angular misalignment, and the like of the shaft relative to the sensor shaft 42. This reduces the mechanical load on the rotation sensor 40, which is integrated into one unit. Note that when the rotation sensor 40 is attached to the holding member 70 after the rotating unit 50 is held by the holding member 70, the eccentricity, angular misalignment, and the like of the shaft are suppressed by the holding member 70, making it easier to assemble the shaft relative to the sensor shaft 42.

[0121] (9) The robot 2 described in (8) has a holding member 70 having a body holding portion 72 that holds the sensor body 41 and a shaft holding portion 73 that protrudes from the body holding portion 72 and surrounds the shaft around the joint axis Ax to hold the shaft, and the coupling member 80 connects the shaft to the sensor shaft 42 within the shaft holding portion 73. The bearing holder can also be used to protect the joint member 80.

[0122] (10) The robot 2 according to (9), wherein the outer periphery of the main body holding portion 72 around the joint axis Ax and the inner and outer peripheries of the shaft holding portion 73 around the joint axis Ax are concentric circles. By forming the holding member 70 in a shape that can be turned, the relative positional accuracy of the bearing holding portion with respect to the main body holding portion 72 can be improved, and positional deviation of the shaft with respect to the sensor shaft 42 can be further suppressed.

[0123] (11) The robot 2 described in any one of (8) to (10), wherein the coupling member 80 is configured to connect the shaft held by the holding member 70 to the sensor shaft 42 while absorbing misalignment between the shaft and the sensor shaft 42. Since the holding member 70 prevents the shaft from shifting in position relative to the sensor shaft 42, the joint member 80 can easily absorb any shift in position of the shaft relative to the sensor shaft 42.

[0124] (12) The robot 2 described in any one of (1) to (11) further includes a motor fixed to the first link and a reducer 60 that transmits the rotation of the motor to the second link so as to rotate the second link around the joint axis Ax relative to the first link. The rotation angle of the second link relative to the first link can be detected without being affected by the deflection and backlash of the reducer 60.

[0125] (13) The robot 2 according to (12), further comprising a motor rotation sensor 30 fixed to the motor and detecting rotation of the motor for rotating the second link relative to the first link. A variety of controls are possible using both the motor rotation sensor 30 and the rotation sensor 40.

[0126] (14) The robot 2 described in (13), wherein the rotation sensor 40 and the motor rotation sensor 30 output detection results in a common data format. The configuration of the controller that acquires information from the rotation sensor 40 and information from the motor rotation sensor 30 can be simplified.

[0127] (15) A robot 2 described in any one of (12) to (14), wherein the motor is connected to the first link from one side in the direction along the joint axis Ax, the second link is connected to the reducer 60 from the other side in the direction along the joint axis Ax, and the holding member 70 is attached to the rotating part 50 from the other side. The space where the motor is not disposed can be used to dispose the rotation sensor 40 .

[0128] (16) The robot 2 described in (15) further includes a bridge member 90 extending from the holding member 70 away from the joint axis Ax and fixed to the first link outside the outer periphery of the second link around the joint axis Ax. The rotation sensor 40 can be easily arranged in a space where a motor is not arranged.

[0129] (17) A robot 2 described in any one of (12) to (14), wherein the motor is connected to the first link from one side in the direction along the joint axis Ax at a position away from the joint axis Ax, the second link is connected to the reducer 60 from the other side in the direction along the joint axis Ax, the rotating part 50 is a shaft that passes through the reducer 60 and protrudes from the second link toward the first link, and the holding member 70 is attached to the shaft from one side and fixed to the first link. The fixing point of the holding member 70 can be easily secured to the first link.

[0130] (18) The robot 2 described in any one of (1) to (17) further includes a third link connected to the second link at a second joint axis Ax and a second rotation sensor 40 that detects the rotation of the third link relative to the second link, wherein the second rotation sensor 40 transmits its detection result to the rotation sensor 40 via serial communication, and the rotation sensor 40 transmits its own detection result and the detection result by the second rotation sensor 40 via serial communication. The number of communication cables can be reduced, and the structure of the robot 2 can be simplified.

[0131] Although the embodiments have been described above, the present disclosure is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present disclosure. For example, the rotation sensor 40 does not necessarily have to have the sensor shaft 42, and may be configured to detect the rotation of the rotating part 50 without using the sensor shaft 42. For example, the first end 51 may protrude into the sensor main body 41, and the code disk 44 may be fixed to the outer periphery of the first end 51 within the sensor main body 41. [Explanation of symbols]

[0132] 2...robot, 40...rotation sensor, 50...rotating part, 70...holding member, Ax...joint axis, 60...reduction gear, 41...sensor main body, 42...sensor shaft, 45...detection part, 71...bearing, 72...main body holding part, 73...shaft holding part, 80...coupling member, PA...position adjustment part, 90...bridge member, 94...cable guide, 91a...first surface, 91b...second surface, 96...first connection surface, 97...second connection surface.

Claims

1. a first link and a second link connected to each other at a joint shaft; a rotating portion fixed to the second link and rotatable about the joint axis relative to the first link; a rotation sensor that detects rotation of the rotating part; a holding member fixed to the first link to hold the rotation sensor and to hold the rotating part so as to be rotatable around the joint axis; A robot equipped with:

2. the rotating portion is a shaft that protrudes from the second link toward the rotation sensor, The holding member holds the shaft via a bearing. The robot according to claim 1.

3. a position adjusting portion that adjusts the position of the holding member relative to the first link; The robot according to claim 1 or 2.

4. a bridge member that is separate from the holding member, is fixed to the holding member so as to extend in a direction away from the joint axis, and is fixed to the first link; The robot according to claim 1.

5. a cable wired from the rotation sensor to the first link; a cable guide for guiding the cable along the bridge member; Further comprising: The robot according to claim 4.

6. the bridge member has a first surface facing the second link and a second surface opposite the first surface, The cable guide guides the cable along the second surface. The robot according to claim 5.

7. the bridge member has a first connection surface and a second connection surface that face the same direction as each other in a direction along the joint axis, the first connection surface is fixed to the first link so as to be in contact with the first link; The second connection surface is fixed to the holding member so as to contact the holding member. The robot according to any one of claims 4 to 6.

8. the rotating portion is a shaft that protrudes from the second link toward the rotation sensor, The rotation sensor a sensor main body held by the holding member; a sensor shaft that rotates around the joint axis relative to the sensor body; a detection unit that detects rotation of the sensor shaft relative to the sensor body; and The robot further includes a coupling member connecting the shaft to the sensor shaft. The robot according to claim 1.

9. The holding member is a body holding portion that holds the sensor body; a shaft holding portion that protrudes from the main body holding portion and surrounds the shaft around the joint axis to hold the shaft; and the coupling member connects the shaft to the sensor shaft within the shaft holding portion; The robot according to claim 8.

10. an outer periphery of the main body holding portion around the joint shaft and an inner periphery and an outer periphery of the shaft holding portion around the joint shaft are concentric circles; The robot according to claim 9.

11. the coupling member is configured to couple the shaft held by the holding member to the sensor shaft while absorbing misalignment between the shaft and the sensor shaft. The robot according to any one of claims 8 to 10.

12. a motor fixed to the first link; a reducer that transmits rotation of the motor to the second link so as to rotate the second link around the joint axis relative to the first link; Further comprising: The robot according to claim 1.

13. a motor rotation sensor fixed to the motor for detecting rotation of the motor for rotating the second link relative to the first link; The robot of claim 12.

14. the rotation sensor and the motor rotation sensor output detection results in a common data format; The robot of claim 13.

15. the motor is connected to the first link from one side in a direction along the joint axis, the second link is connected to the reducer from the other side in a direction along the joint axis, The holding member is attached to the rotating part from the other side. The robot according to any one of claims 12 to 14.

16. a bridge member extending from the holding member in a direction away from the joint axis and fixed to the first link outward from an outer periphery of the second link around the joint axis; The robot of claim 15.

17. the motor is connected to the first link from one side in a direction along the joint shaft at a position away from the joint shaft; the second link is connected to the reducer from the other side in a direction along the joint axis, the rotating portion is a shaft that penetrates the reducer and protrudes from the second link toward the first link, the retaining member is attached to the shaft from the one side and fixed to the first link; The robot according to claim 12 or 13.

18. a third link connected to the second link at a second joint shaft; a second rotation sensor that detects rotation of the third link relative to the second link; Further provided with the second rotation sensor transmits the detection result to the rotation sensor by serial communication; The rotation sensor transmits its own detection result and the detection result of the second rotation sensor via serial communication. The robot according to claim 1 or 2.

Images