Robot and method for manufacturing robot

Abstract

To provide a robot which enables downsizing of an arm, and to provide a method for manufacturing the robot.SOLUTION: A robot 1 includes: a lower arm part 9; an elbow part 11 rotatably connected to the lower arm part 9; a motor 23 housed in the lower arm part 9 and including a motor shaft 31 configured to rotate around a motor axis AxM; a first gear 33 connected to the motor shaft 31 and configured to rotate around the motor axis AxM; a second gear 37 which rotates around a gear axis AxG intersecting the motor axis AxM in conjunction with the first gear 33; and a speed reducer 27 which includes an input shaft 47 configured to rotate around a speed reducer axis AxR corresponding with the gear axis AxG in conjunction with the second gear 37, and an output shaft 51 connected to the elbow part 11 and which reduces a speed of rotation of the input shaft 47 and then transmits the rotation to the output shaft 51.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The disclosed embodiments relate to a robot and a method for manufacturing the robot.

Background Art

[0002] For example, Patent Document 1 describes a joint structure of a robot. This joint structure of the robot includes a hollow first member, a second member, and an actuator that relatively rotates the first member and the second member around a first axis. The actuator includes a motor, a speed reducer, and a power transmission mechanism. The speed reducer is supported around the hollow hole and the first axis, and includes an input member for power of the power transmission mechanism. The power transmission mechanism includes an output member supported around a second axis. The power transmission mechanism includes a first power transmission unit and a second power transmission unit that transmits power between a shaft supported around a third axis and the output member, and a housing that houses them and supports the motor. The housing is detachably attached to the first member at a position radially offset outward with respect to the hollow hole, and the power transmission mechanism and the input member are meshed with each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, the housing that houses the second power transmission unit and supports the motor is attached at a position radially offset outward with respect to the hollow hole of the speed reducer. For this reason, there is a problem that the distance between the first axis of the speed reducer and the end portion located on the opposite side with respect to the first axis of the motor increases, leading to an increase in the size of the first member.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a robot capable of miniaturizing an arm and a method for manufacturing the robot. **Means for Solving the Problems**

[0006] In order to solve the above problems, according to one aspect of the present invention, a robot is applied, which includes a first arm, a second arm rotatably connected to the first arm, a motor housed in the first arm and having a rotating shaft that rotates around a first axis, a first gear connected to the rotating shaft and rotating around the first axis, a second gear that rotates around a second axis intersecting the first axis in conjunction with the first gear, an input shaft that rotates around the second axis in conjunction with the second gear, and an output shaft connected to the second arm, and a speed reducer that decelerates the rotation of the input shaft and transmits it to the output shaft.

[0007] Further, according to another aspect of the present invention, there is provided a method for manufacturing a robot having a first arm and a second arm rotatably connected to the first arm, the method including connecting a second gear that rotates around a second axis intersecting the first axis in conjunction with a first gear that rotates around the first axis of a motor housed in the first arm and is connected to a rotating shaft that rotates around the first axis, to an input shaft that rotates around the second axis in conjunction with the second gear and an output shaft connected to the second arm, and connecting the second gear and the input shaft so that they rotate around the second axis. A method for manufacturing a robot is applied. **Effects of the Invention**

[0008] According to the robot of the present invention, etc., the arm can be miniaturized. **Brief Description of the Drawings**

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described with reference to the drawings.

[0011] <1. Configuration of the Robot> With reference to FIG. 1, an example of the configuration of a robot according to an embodiment will be described. FIG. 1 is a perspective view showing an example of the configuration of a robot according to an embodiment.

[0012] As shown in FIG. 1, the robot 1 is configured as a vertical articulated 6-axis robot having, for example, six joint parts J1 to J6. An end effector (not shown) corresponding to the work performed by the robot 1 is attached to the tip end portion 17a of the robot 1. The end effector is, for example, a robot hand or the like. Note that the robot 1 may be a robot having an axis number other than 6 (for example, 5 axes or 7 axes). Further, the robot 1 may be a robot other than a vertical articulated robot, such as a horizontal articulated robot or a parallel link robot.

[0013] The robot 1 has a base 3, a turning part 5, and an arm 7. The base 3 is fixed to, for example, a floor or a pedestal.

[0014] The slewing unit 5 is supported on the upper end portion of the base 3 so as to be slewing - capable around a rotation axis Ax1 parallel to the vertical direction. The slewing unit 5 is slewing - driven around the rotation axis Ax1 with respect to the upper end portion of the base 3 by the drive of an actuator Ac1 (not shown) provided at a joint portion J1 that rotatably connects the adjacent base 3 and the slewing unit 5.

[0015] The arm 7 is supported on, for example, one side portion of the slewing unit 5. The arm 7 has a lower arm portion 9, an elbow portion 11, an upper arm portion 13, a wrist portion 15, and a flange portion 17.

[0016] The lower arm portion 9 is supported on one side portion of the slewing unit 5 so as to be slewing - capable around a rotation axis Ax2 perpendicular to the rotation axis Ax1. The lower arm portion 9 is slewing - driven around the rotation axis Ax2 with respect to one side portion of the slewing unit 5 by the drive of an actuator Ac2 (not shown) provided at a joint portion J2 that rotatably connects the adjacent slewing unit 5 and the lower arm portion 9.

[0017] The elbow portion 11 is supported at the tip of the lower arm portion 9 so as to be slewing - capable around a rotation axis Ax3 parallel to the rotation axis Ax2. The elbow portion 11 is slewing - driven around the rotation axis Ax3 with respect to the tip of the lower arm portion 9 by the drive of an actuator Ac3 (see FIG. 2 etc. described later) provided at a joint portion J3 that rotatably connects the adjacent lower arm portion 9 and the elbow portion 11.

[0018] The upper arm portion 13 is pivotally supported at the tip of the elbow portion 11 so as to be pivotable around a rotation axis Ax4 perpendicular to the rotation axis Ax3. The upper arm portion 13 is pivotally driven around the rotation axis Ax4 with respect to the tip of the elbow portion 11 by the drive of an actuator Ac4 (not shown) provided at a joint portion J4 that rotatably connects the adjacent elbow portion 11 and the upper arm portion 13.

[0019] The wrist portion 15 is supported at the tip of the upper arm portion 13 so as to be slewing - capable around a rotation axis Ax5 perpendicular to the rotation axis Ax4. The wrist portion 15 is slewing - driven around the rotation axis Ax5 with respect to the tip of the upper arm portion 13 by the drive of an actuator Ac5 (not shown) provided at a joint portion J5 that rotatably connects the adjacent upper arm portion 13 and the wrist portion 15.

[0020] The flange portion 17 is supported at the distal end of the wrist portion 15 so as to be rotatable about a rotation axis Ax6 perpendicular to the rotation axis Ax5. The flange portion 17 is rotationally driven about the rotation axis Ax6 with respect to the distal end portion of the wrist portion 15 by the drive of an actuator Ac6 (not shown) provided at a joint portion J6 that rotatably connects the adjacent wrist portion 15 and the flange portion 17.

[0021] The end effector is attached to the distal end portion 17a of the flange portion 17 and rotates about the rotation axis Ax6 together with the rotation of the flange portion 17 about the rotation axis Ax6.

[0022] The robot 1 having the above configuration is a six-axis robot having six joint portions J1 to J6 provided with six actuators Ac1 to Ac6. Each of the actuators Ac1 to Ac6 that drive the joint portions J1 to J6 is constituted by, for example, a motor and a speed reducer.

[0023] In the above description, the rotation about the rotation axis along the longitudinal direction (or extending direction) of the arm 7 is called "pitching", and the rotation about the rotation axis perpendicular to the longitudinal direction (or extending direction) of the arm 7 is called "yawing" for distinction.

[0024] Note that the configuration of the robot 1 described above is an example and is not limited to the above description. For example, at least one of the actuators Ac1 to Ac6 may be provided with a torque sensor, or a force sensor may be provided on the robot 1. In this case, when the robot 1 receives an external force, for example, by colliding with a person or an object, it is possible to immediately stop the operation or avoid it in the direction opposite to the direction in which the external force acts, and the robot 1 can be configured as a human collaborative robot that can operate together with an operator.

[0025] <2. Configuration of Actuator of Joint Portion> Next, with reference to FIGS. 2 to 6, an example of the configuration of the actuator Ac3 provided at the joint portion J3 will be described. FIG. 2 is a perspective view showing an example of a state where the cover of the lower arm portion 9 of the robot 1 is removed. FIG. 3 is a cross-sectional view showing an example of the configuration of the actuator Ac3 provided at the joint portion J3. FIG. 4 is a cross-sectional view showing an example of a state where the gear unit is removed from the speed reducer in the actuator Ac3. FIG. 5 is an enlarged cross-sectional view of the connecting portion between the second gear of the actuator Ac3 and the input shaft of the speed reducer. FIG. 6 is a cross-sectional view showing an example of the structure of the gear unit in a state where the motor is removed from the gear box.

[0026] As described above, the lower arm portion 9 (an example of the first arm) and the elbow portion 11 (an example of the second arm) are rotatably connected around the rotation axis Ax3 by the joint portion J3. As shown in FIG. 2, the lower arm portion 9 has an opening 19 provided near the tip portion and a cover 21 that closes the opening 19. The cover 21 is fixed to the opening 19 by, for example, a plurality of bolts (not shown). As shown in FIG. 2, in a state where the cover 21 is removed, the actuator Ac3 provided at the joint portion J3 is exposed.

[0027] FIG. 3 shows an example of the configuration of the actuator Ac3. As shown in FIG. 3, the actuator Ac3 has a motor 23, a gear box 25, and a speed reducer 27.

[0028] The motor 23 is housed in the lower arm portion 9. The motor 23 has a motor housing 29 that houses a rotor, a stator, etc., a motor shaft 31 (an example of a rotation shaft) that protrudes from the motor housing 29 and rotates around the motor axis AxM (an example of the first axis), and a first gear 33 that is connected to the motor shaft 31 and rotates around the motor axis AxM. Although not shown, the motor 23 is provided with an encoder, a brake device, etc.

[0029] The gearbox 25 has a housing 35 (an example of a casing), a second gear 37, and a bearing 39. The housing 35 is a box-shaped member that houses the second gear 37 and rotatably supports the second gear 37 by the bearing 39. The bearing 39 is attached to the housing 35 in a state of applying an appropriate preload so as to support both the radial force and the thrust force acting on the second gear 37. One end (the lower end in FIG. 3) of the housing 35 is detachably connected to the motor housing 29 by, for example, bolts or the like. When the motor 23 is connected to the gearbox 25, a gear unit 28 is constituted. The other end (the left end in FIG. 3) of the housing 35 is detachably connected to the support portion 40a of the housing 40 of the lower arm portion 9 by, for example, bolts or the like. That is, the gear unit 28 is detachable from the housing 40 of the lower arm portion 9.

[0030] The second gear 37 rotates around a gear axis AxG (an example of a second axis) in conjunction with the first gear 33 of the motor 23. The gear axis AxG substantially coincides with the rotation axis Ax3. The first gear 33 and the second gear 37 are configured as, for example, bevel gears (mitre gears). The first gear 33, which is the driving-side bevel gear, and the second gear 37, which is the driven-side bevel gear, are meshed with each other, and the motor axis AxM and the gear axis AxG intersect at an angle of, for example, approximately 90 degrees. In this case, "intersect" means that the motor axis AxM and the gear axis AxG are on the same plane and intersect each other. Note that the motor axis AxM and the gear axis AxG may be configured to intersect at an angle other than 90 degrees.

[0031] Note that the first gear 33 and the second gear 37 may have a configuration other than a bevel gear as long as their axes intersect and they rotate in conjunction with each other. For example, the first gear and the second gear may be configured as hypoid gears. In this case, "intersect" means that the motor axis AxM and the gear axis AxG are offset by being on different planes and are in a twisted position where they do not intersect each other. Also, as long as the first gear 33 and the second gear 37 are configured to rotate in conjunction with each other, they do not necessarily have a directly meshing configuration, and for example, a configuration in which some kind of power transmission mechanism such as another gear is interposed between them may be adopted.

[0032] The second gear 37 is formed in a cylindrical shape and has a cylindrical hollow portion 41 (an example of a first hollow portion) that extends along the gear axis AxG inside. Further, the second gear 37 has a hole portion 43 into which a shaft portion 55 of a speed reducer 27 described later is inserted. The hole portion 43 has an uneven portion 45 extending along the gear axis AxG on its inner circumference. The uneven portion 45 will be described later. The hollow portion 41 is the space inside the hole portion 43.

[0033] The speed reducer 27 has an input shaft 47, a fixed portion 49, and an output shaft 51, and decelerates the rotation of the input shaft 47 and transmits it to the output shaft 51. The fixed portion 49 is fixed to a support portion 40a of a housing 40 of the lower arm portion 9. The input shaft 47 is rotatably supported by a bearing 53 with respect to the support portion 40a of the housing 40 of the lower arm portion 9, and rotates around a speed reducer axis AxR (an example of a second axis) in conjunction with the second gear 37. The speed reducer axis AxR substantially coincides with the gear axis AxG and the rotation axis Ax3. The bearing 53 is attached to the support portion 40a in a state where an appropriate pressing pressure is applied so as to support both the radial force and the thrust force acting on the input shaft 47.

[0034] The input shaft 47 has a shaft portion 55 that is inserted into the hole portion 43 of the second gear 37. The shaft portion 55 has an uneven portion 57 extending along the speed reducer axis AxR on its outer circumference. The uneven portion 57 will be described later. The second gear 37 and the input shaft 47 are connected by a so-called spline connection in which the uneven portion 45 provided on the inner circumference of the hole portion 43 and the uneven portion 57 provided on the outer circumference of the shaft portion 55 are fitted together.

[0035] Note that the second gear 37 and the input shaft 47 may be connected by a configuration other than a spline as long as they can transmit the force in the rotational direction and release the force in the thrust direction. For example, a key groove may be formed in either the shaft portion or the hole portion for connection, or the shaft portion and the hole portion may be formed in a polygonal shape for connection. Further, as long as the second gear 37 and the input shaft 47 are configured to rotate in conjunction with each other around a common axis, they do not necessarily have to be directly connected. For example, a configuration in which some kind of power transmission mechanism such as another gear is interposed between them may be adopted.

[0036] The output shaft 51 rotates around the reduction gear axis AxR (i.e., the rotation axis Ax3) with respect to the fixed part 49. The output shaft 51 is fixed to the housing 59 of the elbow 11.

[0037] The input shaft 47, the fixed part 49, and the output shaft 51 have a cylindrical hollow part 61 (an example of the second hollow part) extending along the reduction gear axis AxR. The hollow part 41 of the second gear 37 and the hollow part 61 of the reduction gear 27 communicate in the direction of the reduction gear axis AxR in a state where the second gear 37 and the input shaft 47 are connected. A cylindrical tubular member 63 is inserted into the interior of the communicated hollow part 41 and the hollow part 61. A gap is provided between the outer peripheral surface of the tubular member 63 and the inner peripheral surface of the hollow part 41 of the second gear 37, and between the outer peripheral surface of the tubular member 63 and the inner peripheral surface of the hollow part 61 of the reduction gear 27, respectively. The tubular member 63 is provided with a flange part 63a at one end, and the flange part 63a is detachably connected to the housing 35 by, for example, bolts.

[0038] FIG. 4 shows a state where the cover 21 is removed from the housing 40 of the lower arm part 9 and the gear unit 28 is removed through the opening 19. As shown in FIG. 4, the dimension L1 of the opening 19 in the direction of the motor axis AxM is larger than the sum of the dimension L2 of the housing 35 of the gear box 25 in the direction of the motor axis AxM and the dimension L3 of the motor housing 29 of the motor 23 connected to the housing 35 in the direction of the motor axis AxM, that is, the dimension (L2 + L3) of the gear unit 28 in the direction of the motor axis AxM. Thereby, as shown in FIGS. 2 and 4, when the cover 21 is removed, the entire region including the total length of the gear unit 28 in the direction of the motor axis AxM is exposed toward the side opposite to the reduction gear 27.

[0039] Fig. 5 shows an enlarged view of the connecting portion between the second gear 37 and the input shaft 47. In Fig. 5, the illustration of the cylindrical member 63 is omitted. As shown in Fig. 5, the hole portion 43 of the second gear 37 has, on its inner circumference, uneven portions 45 (an example of the second uneven portion) extending along the gear axis AxG. The uneven portions 45 have a plurality of groove-shaped concave portions 45a extending substantially parallel to the gear axis AxG and a plurality of linear convex portions 45b extending substantially parallel to the gear axis AxG. The concave portions 45a and the convex portions 45b are alternately arranged in the circumferential direction on the inner circumference of the hole portion 43. Note that the uneven portions 45 include a configuration in which only one of the concave portions 45a or the convex portions 45b is provided, and also include a configuration in which the number of the concave portions 45a or the convex portions 45b is not limited to a plurality and only one is provided.

[0040] Further, the shaft portion 55 of the input shaft 47 has, on its outer circumference, uneven portions 57 (an example of the first uneven portion) extending along the speed reducer axis AxR. The uneven portions 57 have a plurality of groove-shaped concave portions 57a extending substantially parallel to the speed reducer axis AxR and a plurality of linear convex portions 57b extending substantially parallel to the speed reducer axis AxR. The concave portions 57a of the shaft portion 55 are fitted with the convex portions 45b of the hole portion 43, and the convex portions 57b of the shaft portion 55 are fitted with the concave portions 45a of the hole portion 43. The concave portions 57a and the convex portions 57b are alternately arranged in the circumferential direction on the outer circumference of the shaft portion 55. Note that the uneven portions 57 include a configuration in which only one of the concave portions 57a or the convex portions 57b is provided, and also include a configuration in which the number of the concave portions 57a or the convex portions 57b is not limited to a plurality and only one is provided.

[0041] The hole portion 43 of the second gear 37 has a space S1 in the concave portion 45 that allows the uneven portion 57 of the shaft portion 55 to move along the direction of the gear axis AxG toward the tip side (the right side in FIG. 5) of the shaft portion 55 when the second gear 37 and the input shaft 47 are connected by fitting the uneven portion 45 of the hole portion 43 and the uneven portion 57 of the shaft portion 55. That is, the space S1 includes a space in the concave portion 45a where the convex portion 57b is not fitted. Further, the shaft portion 55 of the input shaft 47 has a space S2 in the uneven portion 57 that allows the uneven portion 45 to move along the direction of the reduction gear axis AxR toward the base end side (the left side in FIG. 5) of the shaft portion 55 when the second gear 37 and the input shaft 47 are connected by fitting the uneven portion 57 of the shaft portion 55 and the uneven portion 45 of the hole portion 43. That is, the space S2 includes a space in the concave portion 57a where the convex portion 45b is not fitted. Thereby, it is possible to allow the shaft portion 55 and the hole portion 43 to move relatively in the direction of the gear axis AxG (reduction gear axis AxR). Therefore, it is possible to prevent the thrust force generated in the second gear 37 from being transmitted to the input shaft 47 of the reduction gear 27, and to prevent the thrust force generated in the input shaft 47 of the reduction gear 27 from being transmitted to the second gear 37.

[0042] Also, as shown in FIG. 5, for example, a ring-shaped protrusion 40b is formed on the support portion 40a of the housing 40 of the lower arm portion 9, and the housing 35 of the gear box 25 has an opening 35a with a shape (for example, a circular shape) corresponding to the outer periphery of the protrusion 40b. When the opening 35a is fitted to the protrusion 40b, the gear box 25 is positioned so that the gear axis AxG of the second gear 37 and the reduction gear axis AxR of the input shaft 47 substantially coincide. Further, when the tip of the opening 35a abuts against the end face of the support portion 40a of the housing 40, the position of the gear box 25 in the direction of the gear axis AxG (reduction gear axis AxR) is positioned.

[0043] FIG. 6 shows the gear unit 28 with the motor 23 removed from the gear box 25. As described above, since the first gear 33 and the second gear 37 are configured as bevel gears, it is necessary to adjust the meshing between the first gear 33 and the second gear 37. In the present embodiment, as shown in FIG. 6, the meshing between the first gear 33 and the second gear 37 is adjusted with the gear unit 28 removed from the housing 40 of the lower arm portion 9. Specifically, the motor 23 is removed from the gear box 25, and the meshing between the first gear 33 and the second gear 37 is adjusted by changing the thickness of the shim 65 sandwiched between the motor housing 29 and the housing 35. Note that the shim may be provided between the first gear 33 and the motor shaft 31. Note that the adjustment of the meshing may be performed with the cylindrical member 63 attached to the housing 35, or may be performed with the cylindrical member 63 removed from the housing 35.

[0044] The manufacturing method of the robot 1 having the configuration described above includes a step of connecting a second gear 37 that is connected to the motor shaft 31 of the motor 23 housed in the lower arm portion 9 and rotates around the motor axis AxM and rotates in conjunction with the first gear 33, an input shaft 47 that rotates around the reduction gear axis AxR that intersects the motor axis AxM in conjunction with the second gear 37, and an output shaft 51 connected to the elbow 11, and connecting the second gear 37 and the input shaft 47 so as to rotate around the common axes AxG and AxR of the input shaft 47 of the reduction gear 27 that decelerates the rotation of the input shaft 47 and transmits it to the output shaft 51.

[0045] <3. Effects of the Embodiment> As described above, in the robot 1 of the present embodiment, the rotation of the motor shaft 31 by the motor 23 housed in the lower arm portion 9 is transmitted to the input shaft 47 of the speed reducer 27 via the first gear 33 and the second gear 37, and the rotation of the input shaft 47 is decelerated and transmitted to the output shaft 51 connected to the elbow portion 11, whereby the elbow portion 11 rotates with respect to the lower arm portion 9. According to the present embodiment, the second gear 37 and the input shaft 47 of the speed reducer 27 rotate around a common axis AxG, AxR (gear axis AxG, speed reducer axis AxR) that intersects the motor axis AxM. Thereby, the distance L4 (see FIG. 4) between the axes AxG, AxR and the end portion 29a located on the opposite side of the axes AxG, AxR of the motor 23 can be reduced. Therefore, the lower arm portion 9 that houses the motor 23 can be downsized.

[0046] Further, in the present embodiment, the robot 1 may have a housing 35 that rotatably supports the second gear 37 and to which the motor 23 is connected, and the housing 35 may be configured to be detachable from the lower arm portion 9. In this case, by connecting the motor 23 provided with the first gear 33 to the housing 35, the first gear 33, the second gear 37, and the motor 23 can be unitized. Thereby, in a state where the gear unit 28 is removed from the lower arm portion 9, the meshing between the first gear 33 and the second gear 37 can be adjusted, so that the adjustment work becomes easy and the assemblability can be improved.

[0047] Further, in the present embodiment, the input shaft 47 of the speed reducer 27 may have a shaft portion 55 having an uneven portion 57 extending along the speed reducer axis AxR on the outer periphery, and the second gear 37 may have an uneven portion 45 extending along the gear axis AxG and fitting with the uneven portion 57 on the inner periphery, and a hole portion 43 into which the shaft portion 55 is inserted. In this case, the second gear 37 and the input shaft 47 can be connected by a so-called spline connection in which the uneven portion 57 provided on the outer periphery of the shaft portion 55 is fitted into the uneven portion 45 provided on the inner periphery of the hole portion 43. Thereby, for example, compared with the case of connecting via a gear, the adjustment work for meshing is not required, so that the connecting work becomes easy and the assemblability can be improved. Further, noise can be reduced compared with the case of connecting via a gear.

[0048] Further, in the present embodiment, the shaft portion 55 may have, in the concavo-convex portion 57, a space S2 in which the concavo-convex portion 45 of the second gear 37 can move along the direction of the reduction gear axis AxR toward the proximal end side of the shaft portion 55, and the hole portion 43 may have, in the concavo-convex portion 45, a space S1 in which the concavo-convex portion 57 can move along the direction of the gear axis AxG toward the distal end side of the shaft portion 55. In this case, due to the space S1 of the concavo-convex portion 45 and the space S2 of the concavo-convex portion 57, in a state where the second gear 37 and the input shaft 47 are connected, relative movement of the shaft portion 55 and the hole portion 43 in the directions of the axes AxG and AxR can be allowed. Thereby, it is possible to prevent the thrust-direction force generated in the second gear 37 from being transmitted to the input shaft 47 of the reduction gear 27, and also possible to prevent the thrust-direction force generated in the input shaft 47 of the reduction gear 27 from being transmitted to the second gear 37. Therefore, the second gear 37 and the input shaft 47 can be connected so as to transmit the force in the rotational direction while releasing the force in the thrust direction.

[0049] Further, in the present embodiment, the second gear 37 may have a hollow portion 41 extending along the gear axis AxG, and the input shaft 47, the fixing portion 49, and the output shaft 51 may have a hollow portion 61 extending along the reduction gear axis AxR, and the hollow portion 41 and the hollow portion 61 may communicate with each other in the directions of the axes AxG and AxR in a state where the second gear 37 and the input shaft 47 are connected. In this case, a cable can be inserted into the communicating hollow portions 41 and 61. Thereby, the cable can be wired through the gear box 25 and the reduction gear 27 between the inside of the lower arm portion 9 and the inside of the elbow portion 11.

[0050] Further, in the present embodiment, the robot 1 may have a cylindrical member 63 inserted into the hollow portions 41 and 61 communicating with each other in the directions of the axes AxG and AxR. In this case, it is possible to prevent the cable wired inside the hollow portions 41 and 61 from rubbing against the second gear 37, the input shaft 47, etc., which are the surrounding rotating members, so that the cable can be protected. Also, it is possible to prevent the grease of the gear box 25 and the reduction gear 27 from leaking into the hollow portions 41 and 61 where the cable is wired.

[0051] Further, in the present embodiment, the cylindrical member 63 may be configured to be detachable from the housing 35 of the gear box 25. In this case, when adjusting the meshing between the first gear 33 and the second gear 37 in the gear unit 28, the cylindrical member 63 can be removed, facilitating the adjustment work. Also, when connecting the gear unit 28 to the input shaft 47 of the speed reducer 27, it is possible to connect with the cylindrical member 63 attached to the gear unit 28, or to connect with the cylindrical member 63 removed from the gear unit 28 and then attach the cylindrical member 63 to the gear unit 28 after connection. This can improve the degree of freedom in the assembly work. In particular, when the cylindrical member 63 is removed from the gear unit 28, when assembling the gear unit 28 to the speed reducer 27, the relative position between the hole portion 43 of the second gear 37 and the shaft portion 55 of the input shaft 47 of the speed reducer 27 can be visually observed through the hollow portion 41, improving the assemblability.

[0052] Further, in the present embodiment, the lower arm portion 9 may have an opening 19 in which the dimension L1 in the direction of the motor axis AxM is larger than the sum of the dimension L2 of the housing 35 and the dimension L3 of the motor 23 connected to the housing 35, and a cover 21 for closing the opening 19. In this case, since the dimension L1 of the opening 19 is larger than the dimension (L2 + L3) of the gear unit 28, the work of attaching or detaching the gear unit 28 to / from the speed reducer 27 through the opening 19 becomes easy, improving the assemblability. Also, after attaching the gear unit 28, the gear unit 28 can be protected by closing the opening 19 with the cover 21, and the reduction in the appearance of the robot 1 and the strength of the lower arm portion 9 can be suppressed.

[0053] Further, in the present embodiment, the opening 19 may be provided such that when the second gear 37 and the input shaft 47 are connected, the entire housing 35 and the motor 23 connected to the housing 35 are exposed on the side opposite to the speed reducer 27 in the direction of the axial centers AxG and AxR. In this case, since the opening 19 is provided so as to expose the entire gear unit 28, the operation of attaching and detaching the gear unit 28 to and from the speed reducer 27 through the opening 19 becomes easy, and the assemblability can be improved. Further, since the gear unit 28 can be attached to or detached from the speed reducer 27 by moving along the direction of the axial centers AxG and AxR through the opening 19, the automation of attaching or detaching the gear unit 28 becomes easy.

[0054] <4. Modification Example> The disclosed embodiment is not limited to the above, and various modifications are possible without departing from the gist and technical idea thereof.

[0055] In the above, the case where the configuration of the above embodiment is applied to the actuator Ac3 of the joint J3 that rotatably connects the lower arm portion 9 and the elbow portion 11 among the arms 7 of the robot 1 has been described. However, the applicable location is not limited to the actuator Ac3. The configuration of the above embodiment may be applied to the actuator Ac2 of the joint J2 that rotatably connects the swivel unit 5 and the lower arm portion 9, or may be applied to the actuator Ac5 of the joint J5 that rotatably connects the upper arm portion 13 and the wrist portion 15. That is, the configuration of the above embodiment is suitable for the actuator of the joint that pivots around the rotation axis perpendicular to the longitudinal direction (or the extending direction) of the arm 7.

[0056] Also, for example, in the above embodiment, the case where the second gear 37 has the hole portion 43 and the input shaft 47 has the shaft portion 55 has been described. Conversely, the second gear 37 may have a shaft portion, and the input shaft 47 may have a hole portion into which the shaft portion of the second gear 37 is inserted.

[0057] Also, for example, in the above-described embodiment, the case where the first gear 33, the second gear 37, and the motor 23 are unitized has been described. However, if the second gear 37 and the input shaft 47 are configured to rotate around a common axis, the first gear 33, the second gear 37, and the motor 23 do not necessarily have to be unitized.

[0058] In the above description, when there are descriptions such as "vertical", "parallel", "plane", etc., such descriptions are not in a strict sense. Those "vertical", "parallel", "plane" mean "substantially vertical", "substantially parallel", "substantially plane" in that tolerances and errors in design and manufacturing are allowed.

[0059] In the above description, when there are descriptions such as "identical", "the same", "equal", "different", etc. regarding dimensions, sizes, shapes, positions, etc. in appearance, such descriptions are not in a strict sense. Those "identical", "the same", "equal", "different" mean "substantially identical", "substantially the same", "substantially equal", "substantially different" in that tolerances and errors in design and manufacturing are allowed.

[0060] In addition to what has been described above, the methods according to the above-described embodiment and each modification example may be appropriately combined and used. Other than not listing them one by one, the above-described embodiment and each modification example may be implemented with various changes made within the scope not departing from the gist thereof.

[0061] The problems and effects to be solved by the above-described embodiment, modification examples, etc. are not limited to the above-described content. Depending on the embodiment, modification examples, etc., it is also possible to solve problems not described above or achieve effects not described above, or to solve only some of the described problems or achieve only some of the described effects.

Explanation of Reference Numerals

[0062] 1 Robot 9 Lower Arm (an example of the first arm) 11 Elbow (an example of the second arm) 19 Opening 21 Cover 23 Motor 25 Gearbox 27 Reducer 28 Gear unit 29 Motor housing 29 Motor 31 Motor shaft (an example of a rotating shaft) 33 First gear 35 Housing (an example of a casing) 37 Second gear 41 Hollow part (an example of a first hollow part) 43 Hole part 45 Concave-convex part (an example of a second concave-convex part) 47 Input shaft 51 Output shaft 55 Shaft part 57 Concave-convex part (an example of a first concave-convex part) 61 Hollow part (an example of a second hollow part) 63 Cylindrical member 65 Shim Ax3 Rotating shaft (an example of a second axis) AxG Gear axis (an example of a second axis) AxM Motor axis (an example of a first axis) AxR Reducer axis (an example of a second axis) L1 Dimension L2 Dimension L3 Dimension S1 Space S2 Space

Claims

1. a first arm, a second arm rotatably connected to the first arm, a motor housed in the first arm and having a rotating shaft that rotates around a first axis, a first gear connected to the rotating shaft and rotating around the first axis, a second gear that rotates around a second axis intersecting the first axis in conjunction with the first gear, a speed reducer including an input shaft that rotates around the second axis in conjunction with the second gear and an output shaft connected to the second arm, the speed reducer reducing the rotation of the input shaft and transmitting it to the output shaft, a robot having the above components.

2. further comprising a housing that rotatably supports the second gear and to which the motor is connected, wherein the housing is configured to be detachable from the first arm, the robot according to claim 1.

3. One of the second gear and the input shaft has a shaft portion having a first concavo-convex portion extending along the second axis on its outer periphery, The other, which is different from the one of the second gear and the input shaft, has a second concavo-convex portion extending along the second axis and fitting with the first concavo-convex portion on its inner periphery, and has a hole portion into which the shaft portion is inserted, the robot according to claim 2.

4. The shaft portion has, in a state where the second gear and the input shaft are connected, a space in the first concavo-convex portion where the second concavo-convex portion can move along the direction of the second axis toward the proximal end side of the shaft portion, The hole portion has, in a state where the second gear and the input shaft are connected, a space in the second concavo-convex portion where the first concavo-convex portion can move along the direction of the second axis toward the distal end side of the shaft portion, the robot according to claim 3.

5. The second gear has a first hollow portion extending along the second axis, The input shaft has a second hollow portion extending along the second axis, The first hollow portion and the second hollow portion communicate with each other in the direction of the second axis in a state where the second gear and the input shaft are connected, the robot according to claim 3 or 4.

6. further comprising a cylindrical member inserted into the interiors of the first hollow portion and the second hollow portion that communicate with each other in the direction of the second axis, the robot according to claim 5.

7. The cylindrical member is configured to be detachable from the housing, the robot according to claim 6.

8. The first arm an opening whose dimension in the direction of the first axis is larger than the sum of the dimension of the housing in the direction of the first axis and the dimension of the motor connected to the housing in the direction of the first axis; a cover for closing the opening; The robot according to claim 2 or 3.

9. The opening is provided such that, in a state where the second gear and the input shaft are connected, the entire housing and the motor connected to the housing are exposed on the side opposite to the speed reducer in the direction of the second axis. The robot according to claim 8.

10. a first arm; a second arm rotatably connected to the first arm; A method for manufacturing a robot, comprising: a second gear that is connected to a rotating shaft that rotates around a first axis of a motor housed in the first arm and rotates in conjunction with a first gear that rotates around the first axis; an input shaft that rotates around a second axis that intersects the first axis in conjunction with the second gear, and an output shaft connected to the second arm, and with respect to the input shaft of a speed reducer that decelerates the rotation of the input shaft and transmits it to the output shaft, connecting the second gear and the input shaft so as to rotate around the second axis; A method for manufacturing a robot, comprising:

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