Wrist device for robot and robot

Abstract

A wrist device (6) for a robot (1) comprises a first element (61) that is supported at the tip of an arm (30), a second element (62) that is held by the first element, rotates relative to the first element around a rotational axis (Ax7), and supports an end effector, a connection part (64) to which is connected the tip of a hose (52) through which a fluid for operating the end effector flows, a first clamp (81) that fixes a first portion (71) of an electric cable (7) that is connected at the tip to the end effector side to the first element, and a second clamp (82) that fixes a second portion (72) of the electric cable to the second element.

Description

Robot wrist device and robot

[0001] The technology disclosed herein relates to a robot wrist device and a robot.

[0002] Patent Document 1 describes a conventional rotary joint device. The rotary joint device is a device for a wrist of a robot. The rotary joint device rotatably supports a hand or a chuck that holds a workpiece.

[0003] The conventional rotary joint device includes a rotating joint body and a fixed joint body. An air hose that supplies air to an actuator that operates the hand or chuck, electrical wiring that transmits control signals to the solenoid valve, and a current collecting cable that collects the welding current are connected to the fixed joint body. Even when the rotating joint body rotates, the air hose, electrical wiring, and current collecting cable do not move. The conventional rotary joint device prevents the air hose, control signal line, and welding current collecting cable from loosening, dragging, or sagging.

[0004] Japanese Patent Application Publication No. 5-293788

[0005] The conventional rotary joint device has a structure in which the connection of the air supply passage and the electrical connection between the joint stationary body and the joint rotor are maintained even when the joint rotor rotates. The structure of the conventional rotary joint device is complicated.

[0006] The technology disclosed herein relates to a robot wrist device that includes: a first element supported at the tip of an arm; a second element held by the first element, rotatable relative to the first element about a rotation axis, and supporting an end effector; a connection portion supported by the first element and connected to the tip of a hose through which a working fluid for the end effector flows; a first clamp that secures a first portion of an electric cable, the tip of which is connected to the end effector, to the first element; and a second clamp that secures a second portion of the electric cable to the second element.

[0007] The tip of the hose through which the operating fluid of the end effector flows is connected to the connection part, while the electrical cable held by the first clamp and the second clamp is laid outside the wrist device, thereby simplifying the structure of the robot wrist device.

[0008] 1 is a perspective view of a vertical articulated robot, FIG 2 is a perspective view of a wrist device, and FIG 3 is a cross-sectional view of the wrist device.

[0009] Hereinafter, an embodiment of a robot wrist device and a robot will be described with reference to the drawings. The robot wrist device and the robot described here are examples.

[0010] (Overall structure of the articulated robot) Fig. 1 shows the articulated robot 1. Fig. 1 is a perspective view of the articulated robot 1. The articulated robot 1 is a vertical articulated robot. The articulated robot 1 is equipped with a manipulator 3 having a serial link structure. The articulated robot 1 is a seven-axis robot equipped with joints JT1-JT7. The manipulator 3 has an arm 30 and a wrist device 6.

[0011] The articulated robot 1 is used, for example, in the field of logistics. Specifically, the articulated robot 1 loads and unloads items onto and from the bed of a truck or a container. In FIG. 1 , the articulated robot 1 is installed on a floor. The floor is, for example, the floor of the bed of a truck. The articulated robot 1 may also be placed on a cart and moved by the cart. Note that the use of the articulated robot 1 is not limited to logistics applications. The articulated robot 1 can be used in a variety of fields.

[0012] The articulated robot 1 includes a base 21. Note that the base 21 is not an essential element of the articulated robot 1.

[0013] The articulated robot 1 includes a first link 31. The first link 31 is part of the arm 30. Note that the first link 31 is not an essential element of the articulated robot 1. A joint JT1 connects the first link 31 to the base 21. A first end of the first link 31 is connected to the base 21. The first link 31 rotates relative to the base 21 around an axis Ax1. The axis Ax1 is a horizontal axis that is parallel to the floor.

[0014] The articulated robot 1 includes a second link 32. The second link 32 is part of the arm 30. Note that the second link 32 is not an essential element of the articulated robot 1. A joint JT2 connects the second link 32 and the first link 31. A first end of the second link 32 is connected to a second end of the first link 31. The second link 32 rotates relative to the first link 31 around an axis Ax2. The axis Ax2 is an axis parallel to the axis Ax1.

[0015] The articulated robot 1 includes a third link 33. The third link 33 is part of the arm 30. A joint JT3 connects the third link 33 and the second link 32. A first end of the third link 33 is connected to a second end of the second link 32. The third link 33 rotates relative to the second link 32 about an axis Ax3. The axis Ax3 is an axis parallel to the axes Ax1 and Ax2.

[0016] The base 21 rotates around an axis Ax4. The axis Ax4 is an axis perpendicular to the floor and perpendicular to the axis Ax1. The base 21 has a joint JT4. As the base 21 rotates, the first link 31, the second link 32, and the third link 33 rotate around the axis Ax4.

[0017] The joint JT5 rotates the third link 33 about an axis Ax5, which is perpendicular to the axis Ax1.

[0018] The articulated robot 1 includes a wrist device 6. The wrist device 6 is connected to a second end of the third link 33. The joint JT6 rotates the wrist device 6 relative to the third link 33 about an axis Ax6. The axis Ax6 is an axis parallel to the axis Ax1. As will be described later, the joint JT7 rotates the tip 602 of the wrist device 6 relative to the third link 33 about an axis Ax7. The axis Ax7 is an axis perpendicular to the axis Ax1.

[0019] The articulated robot 1 includes an end effector. The end effector is supported by a wrist device 6. The end effector is, for example, a hand that holds an object. Note that a hand that holds an object is not an essential element of the articulated robot 1. The end effector of the articulated robot 1 is selected depending on the application of the articulated robot 1.

[0020] The articulated robot 1 includes a joint JT8. The articulated robot 1 can be called an eight-axis robot. The articulated robot 1 includes a second base 35. The second base 35 is interposed between the floor and the base 21. The base 21 and the second base 35 are offset in position in the horizontal direction. Note that, in the following, the base 21 may be referred to as the first base 21 to distinguish it from the second base 35.

[0021] The joint JT8 rotates the second base 35 about an axis Ax8. The axis Ax8 is parallel to the axis Ax4 and perpendicular to the axis Ax1.

[0022] The articulated robot 1 includes a horizontal link 36. The horizontal link 36 extends horizontally. A first end of the horizontal link 36 is fixed to the second base 35. When the second base 35 rotates, the horizontal link 36 rotates around the axis Ax8. The first base 21 is fixed to a second end of the horizontal link 36. The horizontal link 36 and the second base 35 support the seven-axis articulated robot 1. When the horizontal link 36 rotates, the position of the seven-axis articulated robot 1 changes.

[0023] The second base 35 and the horizontal link 36 are not essential elements of the articulated robot 1. The second base 35 and the horizontal link 36 can be omitted from the articulated robot 1.

[0024] The articulated robot 1 includes an actuator. The actuator is a power source that moves the joints. The actuator is, for example, an electric motor. The electric motor is, for example, a servo motor. The electric motor may be a step motor. However, the actuator is not limited to an electric motor.

[0025] FIG. 1 shows actuators 41, 42, 43, and 44 among the actuators provided in the articulated robot 1.

[0026] The actuator 41 is connected to the joint JT1. The actuator 41 applies a torque about the axis Ax1 to the joint JT1, thereby moving the joint JT1. The actuator 42 is connected to the joint JT2. The actuator 42 applies a torque about the axis Ax2 to the joint JT2, thereby moving the joint JT2. The actuator 43 is connected to the joint JT3. In the illustrated example, the actuator 43 is covered with a cover. The actuator 43 applies a torque about the axis Ax3 to the joint JT3, thereby moving the joint JT3. The actuator 44 is connected to the joint JT4. The actuator 44 moves the joint JT4. Note that the actuators 41, 42, 43, and 44 are not essential elements of the articulated robot 1.

[0027] The actuators are electrically connected to the controller 9 via a harness 51. The harness 51 is laid along the arm 30. The actuators receive control signals from the controller 9 via the harness 51. The controller 9 is a computer including at least a processor, a memory, and an interface. The actuators operate in accordance with the control signals. The articulated robot 1 operates in response to the operation of the actuators.

[0028] The hand that serves as the end effector is, for example, a vacuum hand. The vacuum hand holds an object by suctioning air. Air is an example of a fluid used to operate the end effector. The articulated robot 1 is equipped with a hose 52. The hose 52 is a vacuum hose that connects a vacuum pump and the end effector to each other. As will be described later, the tip of the hose 52 is connected to the wrist device 6. Air flows through the vacuum hose from the end effector to the vacuum pump. The hose 52 is flexible and bendable, and is laid along the arm 30.

[0029] (Basic Structure of the Wrist Device) Fig. 2 shows a perspective view of the wrist device 6. Fig. 3 shows a cross-sectional view of the wrist device 6. The wrist device 6 has a base end 601. The base end 601 is connected to the second end of the third link 33, which is the tip of the arm 30. More specifically, the base end 601 is connected to the second end of the third link 33 via a joint JT6. The base end 601 can rotate around an axis Ax6 relative to the third link 33.

[0030] The wrist device 6 has a tip portion 602. The tip portion 602 is located at the tip of the arm 30, closer to the base end portion 601, and protrudes from the base end portion 601 along the axis Ax7. The tip portion 602 is integral with the base end portion 601. When the base end portion 601 rotates about the axis Ax6, the tip portion 602 also rotates about the axis Ax6. The tip portion 602 also has a swivel joint. The wrist device 6 includes a joint JT7.

[0031] The tip end portion 602 includes a first element 61. The first element 61 is cylindrical and has a first end 611 and a second end 612. The second end 612 is the end opposite to the first end 611 in the direction in which the axis Ax7 extends. Both the first end 611 and the second end 612 of the first element 61 have openings. The first end 611 is fixed to the base end portion 601. The first element 61 is supported on the tip of the arm 30 via the base end portion 601.

[0032] A first connecting portion 64 is fixed to the outer peripheral surface of the first element 61. The tip of the hose 52 is connected to the first connecting portion 64. The first connecting portion 64 penetrates the first element 61 in the radial direction. In FIG. 3, the radial direction corresponds to the up-down direction on the paper. The hose 52 communicates with the hollow portion within the first element 61 via the first connecting portion 64.

[0033] The tip portion 602 includes a second element 62. The second element 62 has a main body 63. The main body 63 is located in a hollow portion within the first element 61. The main body 63 is held against the inner circumferential surface of the first element 61 via a first bearing 641 and a second bearing 642. The first bearing 641 and the second bearing 642 are, for example, rolling bearings.

[0034] The main body 63 has a first support portion 631, a second support portion 632, and an intermediate portion 633. The first support portion 631, the intermediate portion 633, and the second support portion 632 are aligned in the direction in which the axis Ax7 extends. The first support portion 631 is located relatively closer to the third link 33. The first support portion 631 has a circular outer peripheral surface and is supported by the inner peripheral surface of the first element 61 via a first bearing 641. The first bearing 641 is located intermediate between the first end 611 and the second end 612 of the first element 61.

[0035] The intermediate portion 633 is located between the first support portion 631 and the second support portion 632. The intermediate portion 633 has a smaller diameter than the first support portion 631 and the second support portion 632. A space 65 is formed between the outer circumferential surface of the intermediate portion 633 and the inner circumferential surface of the first element 61. The space 65 communicates with the first connection portion 64. The hose 52 connected to the first connection portion 64 communicates with the space 65. The space 65 is part of the fluid passage 60 through which air flows.

[0036] The second support portion 632 is located relatively closer to the end effector. The second support portion 632 substantially closes the opening at the second end 612 of the first element 61. Like the first support portion 631, the second support portion 632 also has a circular outer peripheral surface. The second support portion 632 is supported on the inner peripheral surface of the first element 61 via a second bearing 642. The second bearing 642 is located near the second end 612 of the first element 61. Note that reference numeral 643 denotes a pressing member for the second bearing 642, and the pressing member 643 is fixed to the second end 612 of the first element 61.

[0037] Seals 68, 68 are interposed between the outer circumferential surface of the first support portion 631 and the inner circumferential surface of the first element 61, and between the outer circumferential surface of the second support portion 632 and the inner circumferential surface of the first element 61, respectively. The seals 68, 68 prevent air leakage from the space 65 while allowing the second element 62 to rotate relative to the first element 61. For the seal 68, for example, a VARISEAL (registered trademark) can be used. The use of a VARISEAL can reduce the sliding resistance of the joint JT7.

[0038] The second support portion 632 has a through hole 634. The through hole 634 extends along the axis Ax7, thereby connecting a space 65 within the first element 61 to the outside of the first element 61. A second connection portion 635 is attached to the through hole 634. The second connection portion 635 is connected to the end effector. As indicated by the dashed arrows in FIG. 3 , air flows from the end effector through the second connection portion 635, the through hole 634, the space 65, and the first connection portion 64, in this order, before reaching the hose 52. The space 65 and the through hole 634 form a fluid passage 60 in the wrist device 6 that connects the first connection portion 64 and the second connection portion 635 and through which air flows. The fluid passage 60 maintains communication between the first connection portion 64 and the second connection portion 635 even when the second element 62 rotates relative to the first element 61.

[0039] The second element 62 also has an end effector coupling portion 66. The end effector coupling portion 66 is located outside the second end 612 of the first element 61. The end effector coupling portion 66 is fixed to the outer end surface of the second support portion 632 and rotates together with the second support portion 632 about the axis Ax7. The end effector coupling portion 66 is coupled to and supports the end effector. The end effector rotates together with the second element 62 about the axis Ax7.

[0040] The second element further has an actuator coupling portion 67. The actuator coupling portion 67 is fixed to the first support portion 631. The actuator coupling portion 67 extends along the axis Ax7 and is coupled to the actuator inside the base end portion 601. The actuator coupling portion 67 rotates about the axis Ax7 when driven by the actuator. As the actuator coupling portion 67 rotates, the main body 63, the end effector coupling portion 66, and the end effector rotate about the axis Ax7 relative to the first element 61. Because the second connection portion 635 rotates about the axis Ax7, the wrist device 6 can suck air from the rotating end effector.

[0041] (Cable installation structure in wrist device) The tip of cable 7 is connected to the end effector. Cable 7 is, for example, an electric cable that transmits measurement signals from a sensor in the end effector to controller 9. Cable 7 is installed along arm 30. The base end of cable 7 is connected to controller 9 (see also FIG. 1 ). Since cable 7 is connected to the end effector, it is necessary to install cable 7 appropriately in wrist device 6. This is because it is necessary to prevent slack and dragging of cable 7 caused by rotation of the end effector, and to prevent interference between cable 7 and the end effector, wrist device 6, or arm 30.

[0042] The wrist device 6 includes a first clamp 81 and a second clamp 82. The first clamp 81 secures the first portion 71 of the cable 7 to the first element 61. The wrist device 6 has a first bracket 69. The first bracket 69 supports the first clamp 81. The first bracket 69 is secured to the first element 61 on a side of the first connecting portion 64 closer to the third link 33 in the direction in which the axis Ax7 extends. The first bracket 69 protrudes radially outward from the first element 61. The first portion 71 of the cable 7 is secured to the first element 61 via the first clamp 81 and the first bracket 69.

[0043] The second clamp 82 secures the second portion 72 of the cable 7 to the second element 62. The second portion 72 is located between the tip of the cable 7 and the first portion 71. The wrist device 6 has a second bracket 610. The second bracket 610 supports the second clamp 82. The second bracket 610 is fixed to the end effector coupling portion 66 of the second element 62 and extends in a crank shape from the end effector coupling portion 66 to near the second end 612 of the first element 61. The second clamp 82 is located on the side closer to the end effector across the first connection portion 64 in the direction in which the axis Ax7 extends. As shown in FIG. 3 , the second clamp 82 is closer to the outer circumferential surface of the first element 61 than the first clamp 81 in the radial direction. The second portion 72 of the cable 7 is secured to the second element 62 via the second clamp 82 and the second bracket 610. When the second element 62 rotates around the axis Ax7, the second portion 72 of the cable 7 held by the second clamp 82 moves circumferentially along the outer circumferential surface of the first element 61.

[0044] In the cable 7, a slack portion 73 is located between the first portion 71 and the second portion 72. The slack portion 73 of the cable 7 is located outside the outer circumferential surface of the first element 61. More specifically, the slack portion 73 extends from the first clamp 81 in a first circumferential direction, i.e., from the front right to the rear left of the page in FIG. 2 , along the outer circumferential surface of the first element 61. The slack portion 73 then turns around and extends in a second circumferential direction, i.e., from the rear left to the front right of the page in FIG. 2 , to reach the second clamp 82. The slack portion 73 is laid so as to form a U-shape outside the outer circumferential surface of the first element 61. The slack portion 73 is displaced as shown imaginarily in FIG. 2 as the second element 62 rotates.

[0045] The wrist device 6 also has a third clamp 630. The third clamp 630 holds the hose 52 near its tip, which is connected to the first connection portion 64. The third clamp 630 is supported on the tip of the first bracket 69. As shown in FIG. 3 , the first bracket 69 is bent in a J-shape. The cable 7 is laid together with the hose 52 up to the position of the third clamp 630, and then separated from the hose 52 at the third clamp 630 and held by the first clamp 81.

[0046] (Effects) In the wrist device 6, the cable 7 is held by the first clamp 81 and the second clamp 82, and is laid outside the wrist device 6. Because only the air fluid passage 60 is formed inside the wrist device 6, the structure of the wrist device 6 is simple.

[0047] Additionally, an excess length 73 of the cable 7 between the first clamp 81 and the second clamp 82 is laid in a U-shape along the outer circumferential surface of the first element 61. As shown imaginarily in Figure 2, the excess length 73 is displaced as the second element 62 rotates. The displacement of the excess length 73 allows the relative position of the second clamp 82 and the first clamp 81 to change while suppressing slack and dragging of the cable 7. The excess length 73 allows the second element 62 of the wrist device 6 to rotate relative to the first element 61 without causing slack or dragging of the cable 7.

[0048] Furthermore, since the second clamp 82 is located close to the outer circumferential surface of the first element 61, the second portion 72 of the cable 7 can move stably, and the excess length portion 73 can be displaced along the outer circumferential surface of the first element 61. This is advantageous in suppressing interference between the cable 7 and the end effector, wrist device 6, or arm 30.

[0049] Furthermore, with respect to the direction in which the axis Ax7 extends, the first clamp 81 is located on the side of the first connection part 64 that is closer to the arm 30, and the second clamp 82 is located on the side of the first connection part 64 that is closer to the end effector. Because the U-shaped excess length part 73 is arranged across the first connection part 64, the length of the wrist device 6 in the direction of the axis Ax7 can be shortened.

[0050] (Modification) The robot to which the wrist device 6 is applied is not limited to a seven-axis or eight-axis vertical articulated robot. The wrist device 6 can be applied to, for example, a six-axis vertical articulated robot in which the second link 32 is omitted. Furthermore, the robot to which the wrist device 6 is applied is not limited to a vertical articulated robot.

[0051] The first clamp 81 and the second clamp 82 are not limited to being located separately on either side of the axis Ax7, sandwiching the first connection portion 64. Both the first clamp 81 and the second clamp 82 may be located closer to the arm 30 than the first connection portion 64. Also, both the first clamp 81 and the second clamp 82 may be located closer to the end effector than the first connection portion 64.

[0052] The hose 52 is not limited to the flow of air for operating the vacuum hand. If the end effector has an actuator that operates by receiving a supply of air, the hose 52 may also carry air to be supplied to the end effector. Furthermore, if the end effector has an actuator that operates by receiving a supply of hydraulic oil, the hose 52 may also carry hydraulic oil to be supplied to the end effector.

[0053] (Aspects) The above-described embodiments are specific examples of the following aspects.

[0054] (Aspect 1) A wrist device (6) for a robot (1), comprising: a first element (61) supported on the tip of an arm (30); a second element (62) held by the first element (61) and rotatable relative to the first element (61) about a rotation axis (Ax7) and supporting an end effector; a connection part (64) supported by the first element (61) and to which a tip of a hose (52) through which a working fluid for the end effector flows is connected; a first clamp (81) that fixes a first part (71) of an electric cable (7) whose tip is connected to the end effector side to the first element (64); and a second clamp (82) that fixes a second part (72) of the electric cable (7) to the second element (62).

[0055] The tip of the hose (52) through which the operating fluid of the end effector flows is connected to the connection part (64) of the first element (61), while the first part (71) of the electric cable (7) is fixed to the first element (61) and the second part (72) is fixed to the second element (62). Since the electric cable (7) is laid outside the wrist device (6), the structure of the wrist device (6) of the robot (1) is simplified.

[0056] (Aspect 2) A wrist device (6) for a robot (1) according to aspect 1, wherein the second portion (72) of the electric cable (7) is a portion located between the tip of the electric cable (7) and the first portion (71), the first clamp (81) is located on the side closer to the arm (30) across the connection portion (64) in the direction in which the rotation axis (Ax7) extends, and the second clamp (82) is located on the side closer to the end effector across the connection portion (64).

[0057] Since the first clamp (81) and the second clamp (82) are located separately on either side of the connection part (64), the length of the wrist device (6) in the direction in which the rotation axis (Ax7) extends is short.

[0058] (Aspect 3) A wrist device (6) for a robot (1) according to aspect 1 or 2, wherein in the electric cable (7), an excess portion (73) between the first portion (71) fixed to the first clamp (81) and the second portion (72) fixed to the second clamp (82) has a length that allows relative rotation of the second element (62), and the excess portion (73) extends from the first clamp (81) in a first circumferential direction outside the outer circumferential surface of the first element (61), along the outer circumferential surface, then turns around and extends in a second circumferential direction to reach the second clamp (82).

[0059] The excess length (73) of the electric cable (7) can be laid outside the outer circumferential surface of the first element (61) without interfering with the arm (30) and the wrist device (6). In addition, since the excess length (73) is displaced when the second element (62) rotates relative to the first element (61), slack and dragging of the cable (7) are suppressed.

[0060] (Aspect 4) A wrist device (6) for a robot (1) according to any one of Aspects 1 to 3, further comprising: a first bracket (69) fixed to the first element (61) and supporting the first clamp (81); and a second bracket (610) fixed to the second element (62) and supporting the second clamp (82).

[0061] The first clamp (81) and the second clamp (82) are suitably attached to the wrist device (6) through a first bracket (69) and a second bracket (610) respectively.

[0062] (Aspect 5) The wrist device (6) of the robot (1) according to Aspect 4, further comprising a third clamp (630) that holds the hose (52), and the first bracket (69) supports the third clamp (630).

[0063] The first bracket (69) can be used to hold both the hose (52) and the electric cable (7).

[0064] (Aspect 6) The second element (62) has a main body (63) located inside the cylindrical first element (61) and rotatably held on the inner surface of the first element (61), and a connecting portion (66) coupled to the main body (63) and connected to the end effector outside the first element (61), and the second bracket (610) is fixed to the connecting portion (66). A wrist device (6) for a robot (1) according to Aspect 4 or 5.

[0065] The second clamp (82) supported by the second bracket (610) can rotate together with the second element (62). In addition, since the second bracket (610) is fixed to the connecting portion (66) on the outside of the first element (61), the structure of the wrist device (6) is simple.

[0066] (Aspect 7) A wrist device (6) for a robot (1) described in any one of Aspects 1 to 6, further comprising: a second connection portion (635) fixed to the second element (62) and connected to the end effector; and a fluid passage (60) that connects the connection portion (64) and the second connection portion (635) and through which a fluid for operating the end effector flows.

[0067] The fluid passage (60) allows fluid to flow between a connection (64) fixed to the first element (61) and a second connection (635) fixed to the second element (62).

[0068] (Aspect 8) A robot (1) comprising: an arm (30); a first element (61) supported at the tip of the arm (30); a second element (62) held by the first element (61) and rotatable relative to the first element (61) about a rotation axis (Ax7) and supporting an end effector; a connection part (64) supported by the first element (61) and to which a tip of a hose (52) through which a working fluid for the end effector flows is connected; a first clamp (81) that fixes a first part (71) of an electric cable (7) whose tip is connected to the end effector side to the first element (61); and a second clamp (82) that fixes a second part (72) of the electric cable (7) to the second element (62).

[0069] 1 Articulated robot (robot) 30 Arm 52 Hose 6 Wrist device 60 Fluid passage 61 First element 62 Second element 63 Main body 64 First connection portion (connection portion) 66 End effector coupling portion (coupling portion) 69 First bracket 610 Second bracket 630 Third clamp 635 Second connection portion 71 First portion 72 Second portion 73 Excess length portion 81 First clamp 82 Second clamp Ax7 Axis (rotation axis)

Claims

1. A robot wrist device comprising: a first element supported on the tip of an arm; a second element held by said first element and rotatable relative to said first element about a rotation axis, and supporting an end effector; a connection portion supported by said first element and to which is connected the tip of a hose through which a fluid for operating said end effector flows; a first clamp that secures a first portion of an electric cable, the tip of which is connected to the end effector side, to said first element; and a second clamp that secures a second portion of said electric cable to said second element.

2. A robot wrist device according to claim 1, wherein the second portion of the electric cable is located between the tip of the electric cable and the first portion, the first clamp is located on the side closer to the arm across the connection portion in the direction in which the rotation axis extends, and the second clamp is located on the side closer to the end effector across the connection portion.

3. A robot wrist device according to claim 1 or 2, wherein the excess length of the electric cable between the first portion fixed to the first clamp and the second portion fixed to the second clamp has a length that allows relative rotation of the second element, and the excess length extends from the first clamp in a first circumferential direction outside the outer circumferential surface of the first element, along the outer circumferential surface, then turns around and extends in a second circumferential direction to reach the second clamp.

4. A robot wrist device according to any one of claims 1 to 3, further comprising: a first bracket fixed to the first element and supporting the first clamp; and a second bracket fixed to the second element and supporting the second clamp.

5. A robot wrist device according to claim 4, further comprising a third clamp that holds the hose, and the first bracket supports the third clamp.

6. A robot wrist device according to claim 4 or 5, wherein the second element has a main body located inside the cylindrical first element and rotatably held on the inner circumferential surface of the first element, and a connecting part coupled to the main body and connected to the end effector on the outside of the first element, and the second bracket is fixed to the connecting part.

7. A robot wrist device according to any one of claims 1 to 6, further comprising: a second connection part fixed to the second element and connected to the end effector; and a fluid passageway communicating the connection part with the second connection part and through which a fluid for operating the end effector flows.

8. A robot comprising: an arm; a first element supported on the tip of the arm; a second element held by the first element and rotatable relative to the first element about a rotation axis, and supporting an end effector; a connection portion supported by the first element and to which is connected the tip of a hose through which operating fluid for the end effector flows; a first clamp that fixes a first portion of an electric cable, the tip of which is connected to the end effector side, to the first element; and a second clamp that fixes a second portion of the electric cable to the second element.

Images