power transmission device

Abstract

To provide a wire drive type power transmission device that can rotate a driven member connected to a base so as to be rotatable in two directions in each direction.SOLUTION: A power transmission device includes: a base 9 including a pair of right and left drive pulleys 37; an intermediate member 33 supported to the base so as to be rotatable about a first axis A; and a driven member 35 supported to the intermediate member so as to be rotatable about a second axis B. A pair of left-side wires 39L respectively looped in opposite directions is fixed to the left-side drive pulley and the driven member. A pair of right-side wires 39R respectively looped in opposite directions to each other is fixed to the right-side drive pulley and the driven member. When the drive pulleys 37 rotate the driven member in the same direction about the second axis, an opposite torque about the first axis is applied to the driven member. When the drive pulleys rotate the driven member in the opposite direction about the second axis, a torque in the same direction as about the first axis is applied to the driven member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a wire-driven power transmission device including a wire and a pulley. [Background technology]

[0002] Manipulators in which multiple joints each made up of a wire-pulley system are connected are known (for example, Patent Document 1). Patent Document 1 discloses, as a conventional example, a manipulator in which each joint is made up of a rotation axis and two freely rotatable pulleys (a tightening pulley and a loosening pulley) attached to the rotation axis. The rotation axes are parallel to each other.

[0003] Each tightening pulley has one turn of tightening wire wound around it, and the tip of the tightening wire is fixed at the tip of the finger. By winding the tightening wire with a drive device, each joint rotates and the manipulator bends.

[0004] Each release pulley is connected to a spring by a release wire wound in the opposite direction to the tightening wire, which is used to return the manipulator to its original position after bending. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-211383 Summary of the Invention [Problem to be solved by the invention]

[0006] In humanoid robots and the like, there are cases where it is required to configure a joint that can rotate on two axes, similar to the joints provided in a human wrist. In the manipulator described in Patent Document 1, the rotation axes are parallel to each other. Therefore, there is a problem that the bending direction is limited to one direction perpendicular to the rotation axis, and it is not possible to provide the manipulator with a joint that can rotate on two axes.

[0007] In view of the above background, an object of the present invention is to provide a wire-driven power transmission device that can rotate a driven member connected to a base so as to be rotatable in two directions in each of the directions. [Means for solving the problem]

[0008] In order to solve the above problem, one aspect of the present invention includes a base (9) having a pair of left and right drive pulleys (37) that are independently rotatable, an intermediate member (33) supported on the base so as to be rotatable about a first axis (A), and a driven member (35) supported on the intermediate member so as to be rotatable about a second axis (B) that is perpendicular to the first axis, and a pair of left wires (39L) wound in opposite directions are fixed to the left drive pulley and the driven member, A pair of right wires (39R) wound in opposite directions are fixed to the right drive pulley and the driven member, respectively, and the left wire and the right wire are wound around the intermediate member so as to apply a torque that rotates the driven member around the first axis by the rotation of the corresponding drive pulley. When the torque around the second axis imparted to the driven member via the left wire by the rotation of the left drive pulley and the torque around the second axis imparted to the driven member by the right wire by the rotation of the right drive pulley are in the same direction, The torque about the first axis imparted from the left wire to the driven member and the torque about the first axis imparted from the right wire to the driven member are in opposite directions, and when the torque about the second axis imparted to the driven member via the left wire by rotation of the left driving pulley and the torque about the second axis imparted to the driven member by the right wire by rotation of the right driving pulley are in opposite directions, the torque about the first axis imparted from the left wire to the driven member and the torque about the first axis imparted from the right wire to the driven member are in the same direction.

[0009] According to this aspect, when the left and right drive pulleys are driven to rotate the driven member in the same direction about the second axis, the left wire and the right wire apply torques to the driven member in opposite directions about the first axis, respectively, which cancels out the torques of the driven member about the first axis and rotates the driven member about the second axis.

[0010] On the other hand, when the left and right drive pulleys are driven to rotate the driven member in opposite directions around the second axis, the left wire and the right wire each apply torque to the driven member in the same direction around the first axis. This cancels out the torque on the driven member around the second axis, causing the driven member to rotate around the first axis. In this way, the driven member can be rotated in either direction around the first axis or the second axis, depending on the drive direction of the two drive pulleys.

[0011] In the above aspect, preferably, the torque about the first axis imparted to the driven member when tension is applied to one of the left wires is in the opposite direction to the torque about the first axis imparted to the driven member when tension is applied to the other of the left wires, and the torque about the first axis imparted to the driven member when tension is applied to one of the right wires is in the opposite direction to the torque about the first axis imparted to the driven member when tension is applied to the other of the right wires.

[0012] According to this aspect, the direction of the torque about the first axis that the left wire and the right wire apply to the driven member can be changed depending on the driving direction of the drive pulley.

[0013] In the above aspect, preferably, the intermediate member includes a pair of left idler pulleys (49VL) around which the left wire is wound, and a pair of right idler pulleys (49VR) around which the right wire is wound, respectively.

[0014] According to this aspect, the directions of the left wire and the right wire can be properly guided.

[0015] In the above aspect, preferably, the intermediate member has a pair of lateral sides (41HS) that are perpendicular to the first axis and face in directions away from each other, and a pair of longitudinal sides (41VS) that are perpendicular to the lateral sides and face away from each other, and on the longitudinal sides, the pair of left idler pulleys and the pair of right idler pulleys are each arranged symmetrically with respect to an imaginary plane (P) that is perpendicular to the longitudinal sides and includes the first axis, and each is supported on the longitudinal sides so as to be rotatable on an axis parallel to the longitudinal sides.

[0016] According to this aspect, the directions of the left wire and the right wire can be properly guided.

[0017] In the above aspect, preferably, a pair of lateral idler pulleys (49H) are coaxial with the first shaft and rotatable on the first shaft, and the left wire and the right wire are each wound around the corresponding lateral idler pulley between the drive pulley and the driven member.

[0018] According to this aspect, the directions of the left wire and the right wire can be properly guided.

[0019] In the above aspect, preferably, a pair of lateral idler pulleys (49H) are provided which are coaxial with the first shaft and rotatable about the first shaft, the left wire and the right wire are respectively wound around the corresponding lateral idler pulleys between the drive pulley and the driven member, the pair of left idler pulleys and the pair of right idler pulleys are all of the same shape, and one of the lateral idler pulleys is of the same shape as the other lateral idler pulley.

[0020] According to this aspect, the driving operation of the drive pulley is simplified.

[0021] In the above aspect, preferably, the intermediate member is provided with a through hole (43).

[0022] According to this aspect, a wire for wire driving can be passed through the through hole.

[0023] In the above aspect, preferably, the driven member is provided with an assisted driven portion (13) that is driven by a linear member (19), and the linear member passes through the through hole.

[0024] According to this aspect, since the linear member is disposed so as to pass through the through hole, the linear member is less likely to protrude from the power transmission device, and the driving of the driven member is less likely to be hindered by the linear member.

[0025] In the above aspect, preferably, the base is formed with a recess or a receiving hole (25) for receiving an auxiliary driving device (27) that drives the assisted driven part.

[0026] According to this aspect, by accommodating the assisted driven part in the recess or the accommodation hole, it is possible to make the machine, robot, etc. in which the power transmission device is provided compact. [Effects of the Invention]

[0027] Thus, according to the present invention, it is possible to provide a wire-driven power transmission device that can rotate a driven member connected to a base so as to be rotatable in two directions in each of the directions. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram of a robot provided with a power transmission device according to the present invention; [Figure 2] FIG. 1 is an explanatory diagram illustrating a position where a power transmission device is provided; [Figure 3] Perspective view of a power transmission device [Figure 4] Schematic diagram for explaining the winding state of the left front wire [Figure 5] Schematic diagram for explaining the winding state of the left rear wire [Figure 6] Schematic diagram for explaining the winding state of the right front wire [Figure 7] Schematic diagram for explaining the winding state of the right rear wire [Figure 8] 1A and 1B are side and front views of a power transmission device for explaining the direction of torque applied to an intermediate member and a driven pulley when a left front wire is pulled. [Figure 9] 1A and 1B are side and front views of a power transmission device for explaining the direction of torque applied to an intermediate member and a driven pulley when a left rear wire is pulled. [Figure 10]1A and 1B are side and front views of a power transmission device for explaining the direction of torque applied to an intermediate member and a driven pulley when a right front wire is pulled. [Figure 11] 1A and 1B are side and front views of a power transmission device for explaining the direction of torque applied to an intermediate member and a driven pulley when a right rear wire is pulled. [Figure 12] A table summarizing the directions of torques applied to the intermediate member and driven pulley from the left and right wire pairs, respectively. [Figure 13] A table summarizing the rotation directions of the left and right drive pulleys and the manner in which the intermediate member and driven member are rotated. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0030] The power transmission device 1 is provided in the robot hand 5 of the humanoid robot 3, and constitutes part of the drive device 7 for driving the robot hand 5. As shown in FIG. 1, the robot hand 5 constitutes the portion of the humanoid robot 3 that corresponds to the portion from the upper arm to the fingertips of a human. The robot hand 5 is driven in roughly the same way as a human, and can grasp an object by moving its fingers, for example.

[0031] First, a description will be given of the robot hand 5 provided with the power transmission device 1. As shown in FIG.

[0032] The lower arm 9 has a shape corresponding to a human lower arm. The lower arm 9 extends in a predetermined direction. The base end of the lower arm 9 is connected to the trunk 17 via the upper arm 15. The palm 11 is connected to the tip of the lower arm 9. Hereinafter, the extension direction of the lower arm 9 will be referred to as the X-axis direction, the trunk side as the negative X-axis direction, and the fingertip side as the positive X-axis direction.

[0033] The palm portion 11 has a shape corresponding to a human palm. The palm portion 11 is connected to the extending end of the lower arm portion 9. The joint connecting the palm portion 11 and the lower arm portion 9 corresponds to the joint of a human wrist (radiocarpal joint). Because the joint of a human wrist is a biaxial joint, the joint connecting the palm portion 11 and the lower arm portion 9 is also configured to be rotatable about two axes.

[0034] Specifically, as shown in Figure 2, the palm 11 rotates from an extended position extending from the lower arm 9 in a direction along the X-axis to a bent position in which the joint connecting the palm 11 to the lower arm 9 is bent. Hereinafter, the direction in which the palm 11 bends will be referred to as the Y-axis (see Figure 1), and the direction of the axis of rotation of the palm 11 will be referred to as the Z-axis direction. The palm 11 is connected to the lower arm 9 so as to be rotatable in both the Y-axis and Z-axis directions.

[0035] The fingers 13 are connected to the palm 11. Each finger 13 has a plurality of links rotatably connected to one another via joints, and a wire for rotating the links. By selectively applying a pulling force to the wire, the fingers 13 can be displaced between a bent state where they are bent at the joints and an extended state where they are extended. Hereinafter, the wire for extending and bending the fingers 13 will be referred to as a finger drive wire 19.

[0036] As shown in FIG. 3 , the lower arm 9 includes a lower arm main body 21 extending in the X direction and a pair of side plates 23 provided on the lower arm main body 21. In this embodiment, the lower arm main body 21 extends in the X direction and has a frame shape with two receiving holes 25 penetrating in the Y direction. In this embodiment, the lower arm main body 21 is provided with flat fastening surfaces 21A on both outer edges in the Z direction. The two side plates 23 are aligned in the Z direction and arranged facing each other with a gap between them. The opposing surfaces of the two side plates 23 are fastened to the fastening surfaces 21A of the lower arm main body 21. The width of the end of the lower arm main body 21 on the negative side in the X axis direction is smaller than the distance between the two side plates 23. Two gaps aligned in the Z direction are provided between the negative ends of the two side plates 23 and the negative end of the lower arm main body 21 on the negative side in the X axis direction.

[0037] One of the housing holes 25 of the lower arm 9 (hereinafter referred to as the first housing hole 25A and the other housing hole 25 as the second housing hole 25B) houses at least a part of a finger drive device 27 for driving the finger 13. The finger drive device 27 includes a finger driven pulley 27A around which the finger drive wire 19 is wound, a finger drive pulley 27B to which the finger drive wire 19 is fixed, and a finger actuator 27C for driving the finger drive pulley 27B. In this embodiment, the finger actuator 27C is configured by a motor that rotates the finger drive pulley 27B. The first housing hole 25A houses the finger driven pulley 27A of the finger drive device 27. When the finger actuator 27C pulls or releases the finger drive wire 19, the finger 13 is displaced between an extended state and a bent state. In this embodiment, each finger driven pulley 27A has a groove (not shown) on its outer circumferential surface, and is rotatably supported by the lower arm 9 so that the groove faces the connecting portion between the palm 11 and the lower arm 9.

[0038] The driving device 7 drives the palm portion 11 to rotate relative to the lower arm 9 about two axes perpendicular to the extension direction of the lower arm 9. In addition to the power transmission device 1, the driving device 7 further includes a pair of actuators 31. The power transmission device 1 transmits the power of the actuators 31 to the palm portion 11, and serves to rotate the palm portion 11 about two axes (Y-axis and Z-axis) perpendicular to the lower arm 9.

[0039] The actuators 31 are provided on the lower arm 9, the upper arm 15, and the body 17. Each actuator 31 is constituted by a motor. In this embodiment, the actuators 31 are accommodated in and fixed to second accommodation holes 25B provided in the lower arm main body 21. The rotation axis of the actuators 31 passes through a through-hole (not shown) in the lower arm main body 21 and extends into the gap between the end of the lower arm main body 21 on the negative side in the X direction and the end of the side plate 23 on the negative side in the X direction.

[0040] The power transmission device 1 includes a lower arm portion 9 (base), an intermediate member 33 connected to the lower arm portion 9, a driven member 35 connected to the intermediate member 33 and connected to the palm portion 11, a pair of drive pulleys 37, and two pairs of wires 39.

[0041] The drive pulleys 37 are all identical in shape. The drive pulleys 37 are housed in the gaps between the X-axis negative end of each of the two side plate portions 23 and the X-axis negative end of each of the lower arms 9. The drive pulleys 37 are aligned in the Z-axis direction. Each drive pulley 37 is coaxial with the axis of the rotation shaft of the actuator 31 and is fixed to the rotation shaft of the actuator 31. Driven by the actuator 31 connected to it, each drive pulley 37 can independently rotate in both directions relative to the lower arms 9. Hereinafter, the drive pulley 37 located on the positive side of the Z-axis direction will be referred to as the left drive pulley 37L, and the drive pulley 37 located on the negative side of the Z-axis direction will be referred to as the right drive pulley 37R. Furthermore, the actuator 31 that rotationally drives the left drive pulley 37L will be referred to as the left actuator 31L, and the actuator 31 that rotationally drives the right drive pulley 37R will be referred to as the right actuator 31R.

[0042] In this embodiment, the intermediate member 33 has two pairs of side walls 41 facing each other and is shaped like a rectangular frame with a through hole 43. The finger driving wire 19 is inserted through the through hole 43.

[0043] The intermediate member 33 is disposed between the two side plate portions 23. Of the side walls 41 constituting the intermediate member 33, a pair of side walls 41 are disposed so as to face the side plate portions 23 (i.e., face in the Z direction). Hereinafter, the pair of side walls 41 facing the side plate portions 23 will be referred to as horizontal side walls 41H, and the other pair of side walls 41 will be referred to as vertical side walls 41V.

[0044] The lateral side walls 41H are provided with cylindrical shaft portions 45 that protrude in directions that separate from each other in the Z direction. Each side plate portion 23 is provided with a through hole 23A that penetrates along an axis line (hereinafter referred to as first axis A) that extends in the Z axis direction, and each shaft portion 45 is rotatably received in the through hole 23A via a known bearing. As a result, the intermediate member 33 is supported by the side plate portion 23 (i.e., the lower arm portion 9) so as to be rotatable about the first axis A.

[0045] The outer surfaces of the horizontal side walls 41H in the Z direction constitute a pair of horizontal side surfaces 41HS that are perpendicular to the first axis A and face in directions away from each other. The opposing surfaces of the vertical side walls 41V constitute a pair of vertical side surfaces 41VS that are perpendicular to the first axis A and face in directions away from each other. That is, the intermediate member 33 has, as surfaces that constitute its outer circumferential surface, a pair of horizontal side surfaces 41HS that are perpendicular to the first axis A and face in directions away from each other, and a pair of vertical side surfaces 41VS that are perpendicular to the horizontal side surfaces 41HS and face in directions away from each other.

[0046] The driven member 35 includes a driven pulley 35A provided on one vertical side wall 41V (hereinafter referred to as the rear vertical wall) of the intermediate member 33, and a plate-shaped portion 35B connecting the driven pulley 35A and the palm portion 11. The driven pulley 35A is rotatably supported on one vertical side wall 41V at its base end. In this embodiment, the driven pulley 35A is coupled to the outer surface of the rear vertical wall (hereinafter referred to as the rear vertical side surface 41VS) so as to be rotatable about an axis (second axis B) perpendicular to the outer surface. The second axis B is orthogonal to (intersects at a right angle with) the first axis A. The plate-shaped portion 35B is fixed to the protruding end surface of the driven pulley 35A, and the palm portion body is fixed to the plate-shaped portion 35B.

[0047] 2, in addition to the driven pulley 35A and the plate-shaped portion 35B, the driven member 35 includes an auxiliary driven portion 35C and a connecting portion 35D. The auxiliary driven portion 35C is supported on the other vertical side wall 41V of the intermediate member 33 so as to be rotatable about the second axis B. The connecting portion 35D is connected to the tip of the auxiliary driven portion 35C at its base end, extends in the X-axis direction, then bends toward the negative side of the Y-direction, and connects to the plate-shaped portion 35B at its tip end. The plate-shaped portion 35B, the auxiliary driven portion 35C, and the connecting portion 35D are integral with the driven pulley 35A, and rotate around the second axis B in response to the rotation of the driven pulley 35A.

[0048] Of the two pairs of wires 39, one pair of wires (hereinafter referred to as left wire pair 39L, also referred to as left wires) connects the left driving pulley 37L and the driven pulley 35A, and transmits the power of the left driving pulley 37L to the driven pulley 35A. Of the two pairs of wires 39, the other pair of wires (hereinafter referred to as right wire pair 39R, also referred to as right wires) connects the right driving pulley 37R and the driven pulley 35A, and transmits the power of the right driving pulley 37R to the driven pulley 35A.

[0049] A plurality of idler pulleys 49 (hereinafter referred to as idler pulley group 49G) are provided in the connection path of each wire 39 to change the direction of power transmission and rotate the intermediate member 33. First, the idler pulley group 49G will be described, and then the connection path of the wire 39 will be described in detail.

[0050] As shown in FIG. 4, the idler pulley group 49G includes a pair of horizontal idler pulleys 49H provided between the side plate portion 23 and the intermediate member 33, and four vertical idler pulleys 49V provided on the intermediate member 33.

[0051] The pair of lateral idler pulleys 49H have the same shape. The lateral idler pulleys 49H are disposed between the lateral side wall 41H and the side plate portion 23 at an interval in the Z-axis direction. The lateral idler pulleys 49H are connected to the shaft portions 45 via bearings. As a result, the lateral idler pulleys 49H are disposed coaxially with the first axis A and are supported on the lateral side surface 41HS for rotation about the first axis A. As a result, the lateral idler pulleys 49H are rotatable independently of the intermediate member 33. Hereinafter, the lateral idler pulley 49H located on the positive side of the Z-axis direction will be referred to as the left lateral idler pulley 49HL, and the lateral idler pulley 49H located on the negative side of the Z-axis direction will be referred to as the right lateral idler pulley 49HR.

[0052] All vertical idler pulleys 49V have the same shape. Vertical idler pulleys 49V are provided at the four corners of the rear vertical wall.

[0053] The two vertical idler pulleys 49V (hereinafter referred to as left vertical idler pulleys 49VL, or left idler pulleys) located on the positive side of the Z axis direction are arranged in pairs, perpendicular to the rear vertical side surface 41VS and symmetrical with respect to an imaginary plane P including the first axis A. Each of the pair of left vertical idler pulleys 49VL is supported by the intermediate member 33 so as to be rotatable about an axis parallel to the rear vertical side surface 41VS. The outer peripheral surface of the left vertical idler pulley 49VL is provided with a groove portion that extends circumferentially and is recessed in the axial direction. Each of the groove portions is recessed in a direction perpendicular to the rear vertical side surface 41VS.

[0054] Hereinafter, when the intermediate member 33 is positioned so that the second axis B extends in the Y direction and the rear vertical side surface 41VS faces the negative side in the Y direction, the left vertical idler pulley 49VL located on the positive side of the X axis direction will be referred to as the upper left vertical idler pulley 49LU, and the left vertical idler pulley 49VL located on the negative side of the X axis direction will be referred to as the lower left vertical idler pulley 49LD.

[0055] The two vertical idler pulleys 49V (hereinafter referred to as right vertical idler pulleys 49VR, or right side idler pulleys) located on the negative side of the Z axis direction are arranged in pairs, perpendicular to the rear vertical side surface 41VS and symmetrical with respect to an imaginary plane P (see also FIG. 8A) that includes the first axis A. Each of the pair of right vertical idler pulleys 49VR is supported by the intermediate member 33 so as to be rotatable about an axis parallel to the rear vertical side surface 41VS. The outer peripheral surface of the right vertical idler pulley 49VR is provided with a groove that extends circumferentially and is recessed in the axial direction. Each of the grooves is recessed in a direction perpendicular to the rear vertical side surface 41VS.

[0056] Hereinafter, when the intermediate member 33 is positioned so that the second axis B extends in the Y direction and the rear vertical side surface 41VS faces the negative side in the Y direction, the right vertical idler pulley 49VR located on the positive side of the X axis direction will be referred to as the upper right vertical idler pulley 49RU, and the right vertical idler pulley 49VR located on the negative side of the X axis direction will be referred to as the lower right vertical idler pulley 49RD.

[0057] Next, the left wire pair 39L will be described.

[0058] The left wire pair 39L connects the left drive pulley 37L and the driven pulley 35A. As shown in Figures 4 and 5, one end of the left wire pair 39L (hereinafter referred to as the left front wire 39LF) and the other end of the left wire pair 39L (hereinafter referred to as the left rear wire 39LR) are wound around and fixed to the left drive pulley 37L. The left front wire 39LF and the left rear wire 39LR are each wound around the left drive pulley 37L in opposite directions. As shown in Figure 4 (also see Figure 8(A)), the left front wire 39LF is fixed to the left drive pulley 37L at one end, and is wound around the left drive pulley 37L in a right (clockwise) direction when viewed from the Z-axis direction positive side. As shown in FIG. 5 (also see FIG. 9(A)), the left rear wire 39LR is fixed at one end to the left drive pulley 37L and is wound around the left drive pulley 37L counterclockwise when viewed from the Z axis positive side.

[0059] As shown in Figure 4, the left front wire 39LF extends in the positive direction of the X-axis, and when viewed from the positive side of the Z-axis, is wound around the left horizontal idler pulley 49HL in a right (clockwise) direction, and is wound around the upper left vertical idler pulley 49LU and the driven pulley 35A, respectively, and is fixed to the driven pulley 35A.

[0060] 5, the left rear wire 39LR extends in the positive direction of the X axis, is wound counterclockwise (counterclockwise) around the left horizontal idler pulley 49HL as viewed from the positive side of the Z axis, is wound around the lower left vertical idler pulley 49LD and the driven pulley 35A, and is fixed to the driven pulley 35A. The left wire pair 39L (the left front wire 39LF and the left rear wire 39LR) is wound around the left horizontal idler pulley 49HL between the drive pulley 37 and the driven pulley 35A.

[0061] 4 and 5, the winding direction of the left front wire 39LF around the driven pulley 35A and the winding direction of the left rear wire 39LR around the driven pulley 35A are set to be opposite to each other. In detail, when viewed from the negative side in the Y axis direction, the left front wire 39LF is wound around the driven pulley 35A in a right (clockwise) direction (see also FIG. 8(B)), and the left rear wire 39LR is wound around the driven pulley 35A in a left (counterclockwise) direction (see also FIG. 9(B)).

[0062] Next, the right wire pair 39R will be described.

[0063] The right wire pair 39R connects the right drive pulley 37R and the driven pulley 35A. One end of the right wire pair 39R (hereinafter referred to as the right front wire 39RF) and the other end of the right wire pair 39R (hereinafter referred to as the right rear wire 39RR) are wound around and fixed to the right drive pulley 37R. The right front wire 39RF and the right rear wire 39RR are each wound around the right drive pulley 37R in opposite directions. As shown in FIG. 6 (also see FIG. 10(A)), the right front wire 39RF is fixed to the right drive pulley 37R at one end and is wound around the right drive pulley 37R in a clockwise direction as viewed from the positive side of the Z axis direction. As shown in FIG. 7 (also see FIG. 11(A)), the right rear wire 39RR is wound around the right drive pulley 37R in a counterclockwise direction as viewed from the positive side of the Z axis direction.

[0064] As shown in Figure 6, the right front wire 39RF extends in the positive direction of the X-axis, and when viewed from the positive side of the Z-axis, is wound around the right horizontal idler pulley 49HR in a right (clockwise) direction, and is wound around the upper right vertical idler pulley 49RU and the driven pulley 35A in the order shown, and is fixed to the driven pulley 35A.

[0065] 7, the right rear wire 39RR extends in the positive direction of the X-axis, is wound counterclockwise (counterclockwise) around the right lateral idler pulley 49HR as viewed from the positive side of the Z-axis, and is wound around the lower right vertical idler pulley 49RD and the driven pulley 35A in the order shown, and is fixed to the driven pulley 35A. The right wire pair 39R (the right front wire 39RF and the right rear wire 39RR) is wound around the right lateral idler pulley 49HR between the drive pulley 37 and the driven member 35.

[0066] 6 and 7, the winding direction of the right front wire 39RF around the driven pulley 35A and the winding direction of the right rear wire 39RR around the driven pulley 35A are set to be opposite to each other. In detail, when viewed from the negative side in the Y axis direction, the right front wire 39RF is wound around the driven pulley 35A in the left direction (counterclockwise) (see also FIG. 10(B)), and the right rear wire 39RR is wound around the driven pulley 35A in the right direction (clockwise) (see also FIG. 11(B)).

[0067] In this way, the idler pulley group 49G can effectively guide the left wire pair 39L and the right wire pair 39R in the extending direction.

[0068] Next, the operation of the power transmission device 1 configured as above will be described.

[0069] When the left actuator 31L rotates the left drive pulley 37L counterclockwise (hereinafter referred to as the positive direction) as viewed from the Z axis direction positive side, the left front wire 39LF is pulled as shown in FIGS. 8(A) and 8(B).

[0070] At this time, as shown in FIG. 8(A), a torque is applied to rotate the driven pulley 35A counterclockwise around the first axis A as viewed from the positive side in the Z axis direction. Hereinafter, with regard to the torque that rotates the driven pulley 35A around the first axis A, the counterclockwise direction as viewed from the positive side in the Z axis direction will be referred to as the positive direction, and the clockwise direction as the negative direction (see the + and - signs in FIG. 8(A)). Note that the torque here refers to the moment around the rotation axis of the force acting from each of the wires 39, and the driven pulley 35A rotates according to the sum of the torques applied from all of the wires 39. When the left drive pulley 37L is rotated by driving the left actuator 31L and the left front wire 39LF is pulled, a torque is applied to the driven pulley 35A that rotates the driven pulley 35A in the positive direction around the first axis A.

[0071] 8(B), a torque is further applied to the driven pulley 35A to rotate the driven pulley 35A counterclockwise around the second axis B as viewed from the negative Y-axis direction. Hereinafter, with regard to the torque to rotate the driven pulley 35A around the second axis B, when the second axis B extends in the Y direction and the rear vertical side surface 41VS faces the negative Y-axis direction, the counterclockwise direction is referred to as the positive direction and the clockwise direction is referred to as the negative direction (in other words, when viewed along the second axis B toward the rear vertical side surface 41VS) (see the + and - signs in FIG. 8(B)). When the left actuator 31L is driven to rotate the left driving pulley 37L and pull the left front wire 39LF, a torque is applied to the driven pulley 35A to rotate the driven pulley 35A in the negative direction around the second axis B.

[0072] In this way, when the left actuator 31L rotates the left driving pulley 37L in the positive direction, a torque that rotates the driven pulley 35A in the positive direction around the first axis A and a torque that rotates the driven pulley 35A in the positive direction around the second axis B are simultaneously applied to the driven pulley 35A.

[0073] As shown in FIG. 9(A), when the left actuator 31L rotates the left drive pulley 37L clockwise, ie, in the negative direction, as viewed from the Z axis direction positive side, the left rear wire 39LR is pulled.

[0074] At this time, a torque is applied to the driven pulley 35A in the opposite direction to that in the case of the left front wire 39LF, i.e., a torque that rotates the driven pulley 35A clockwise about the first axis A (a torque that rotates in the negative direction about the first axis A) when viewed from the positive side of the Z axis direction.

[0075] Also, as shown in Figure 9(B), a torque is applied to driven pulley 35A that rotates driven pulley 35A clockwise around second axis B when viewed from the negative side of the Y axis direction, i.e., a torque that rotates driven pulley 35A in the negative direction.

[0076] In this way, when the left actuator 31L rotates the left drive pulley 37L in the negative direction, the left rear wire 39LR is pulled, and a torque that rotates the driven pulley 35A in the negative direction around the first axis A and a torque that rotates the driven pulley 35A in the negative direction around the second axis B are simultaneously applied.

[0077] In this way, the torque around the first axis A imparted to the driven pulley 35A when tension is applied to one of the left wire pair 39L is in the opposite direction to the torque around the first axis A imparted to the driven pulley 35A when tension is applied to the other of the left wire pair 39L.

[0078] Similarly, when the right actuator 31R rotates the right drive pulley 37R counterclockwise (hereinafter referred to as the positive direction) as viewed from the Z axis positive side, the right front wire 39RF is pulled. As a result, as shown in Fig. 10(A), a torque is applied to the driven pulley 35A to rotate it in the positive direction about the first axis A. As shown in Fig. 10(B), the right front wire 39RF is also wound around the driven pulley 35A counterclockwise as viewed from the Y axis negative side, so when the right front wire 39RF is pulled, a torque is applied to the driven pulley 35A to rotate it in the negative direction about the second axis B.

[0079] Similarly, when the right actuator 31R rotates the right drive pulley 37R clockwise (hereinafter referred to as the negative direction) as viewed from the positive side of the Z axis direction, the right rear wire 39RR is pulled. As a result, as shown in Fig. 11(A), a torque is applied to the driven pulley 35A to rotate it in the negative direction about the first axis A. As shown in Fig. 11(B), the right rear wire 39RR is also wound around the driven pulley 35A clockwise as viewed from the negative side of the Y axis direction. Therefore, when the right rear wire 39RR is pulled, a torque is applied to the driven pulley 35A to rotate it in the positive direction about the second axis B.

[0080] In this way, the torque about the first axis A imparted to the driven pulley 35A when tension is applied to one of the right wire pair 39R is opposite in direction to the torque about the first axis A imparted to the driven pulley 35A when tension is applied to the other of the right wire pair 39R. The wires 39 of the left wire pair 39L and the wires 39 of the right wire pair 39R, which are imparted to the driven pulley 35A about the first axis A in the same direction when pulled, each imparts a torque about the second axis B in an opposite direction to the driven pulley 35A when pulled.

[0081] 12 shows a table summarizing the directions of the torques applied to driven pulley 35A from left wire pair 39L and right wire pair 39R. In FIG. 12, the positive direction of torque is indicated as +, and the negative direction is indicated as −.

[0082] As can be seen from Figure 12, when the left driving pulley 37L and the right driving pulley 37R are driven to rotate the driven pulley 35A in the same direction about the second axis B, the left wire pair 39L and the right wire pair 39R apply torques to the driven pulley 35A in opposite directions about the first axis A. In this case, in the direction of the second axis B, torques are applied to the driven pulley 35A from the left wire pair 39L and the right wire pair 39R to rotate it in the same direction, so the driven pulley 35A rotates according to the direction of the torques. On the other hand, in the direction of the first axis A, torques are applied in opposite directions from the left wire pair 39L and the right wire pair 39R, so rotation of the driven pulley 35A about the first axis A is prevented. As a result, the driven pulley 35A rotates only about the second axis B.

[0083] Specifically, when the left actuator 31L rotates the left driving pulley 37L in the positive direction and the right actuator 31R rotates the right driving pulley 37R in the negative direction, the driven pulley 35A rotates in the positive direction about the second axis B while rotation of the driven pulley 35A about the first axis A is blocked. When the left actuator 31L rotates the left driving pulley 37L in the negative direction and the right actuator 31R rotates the right driving pulley 37R in the positive direction, the driven pulley 35A rotates about the second axis B while rotation of the driven pulley 35A about the first axis A is blocked. Thus, the power transmission device 1 allows the driven pulley 35A to rotate bidirectionally only about the second axis B, thereby realizing the rotational movement of the joint between the palm 11 and the lower arm 9 of the robot arm.

[0084] Furthermore, when the left driving pulley 37L and the right driving pulley 37R are driven to rotate the driven pulley 35A in opposite directions about the second axis B, the left wire pair 39L and the right wire pair 39R each apply torque in the same direction to the driven pulley 35A about the first axis A. At this time, torques are applied to the driven pulley 35A from the left wire pair 39L and the right wire pair 39R to rotate it in opposite directions about the first axis A, preventing the driven pulley 35A from rotating about the second axis B. On the other hand, torques in the same direction are applied to the driven pulley 35A about the first axis A from the left wire pair 39L and the right wire pair 39R, causing the driven pulley 35A to rotate about the first axis A in accordance with the direction of the torques.

[0085] Specifically, when the left actuator 31L rotates the left driving pulley 37L in the positive direction and the right actuator 31R rotates the right driving pulley 37R in the positive direction, the driven pulley 35A rotates in the positive direction about the first axis A while the rotation of the driven pulley 35A is blocked. When the left actuator 31L rotates the left driving pulley 37L in the negative direction and the right actuator 31R rotates the right driving pulley 37R in the negative direction, the driven pulley 35A rotates in the negative direction about the first axis A while the rotation of the driven pulley 35A about the second axis B is blocked. This allows the palm 11 to be displaced between an extended position and a flexed position, thereby realizing flexion and extension of the joint between the palm 11 and the lower arm 9.

[0086] 13 shows a table summarizing the rotation directions of the left and right drive pulleys 37 and the manner of rotational drive of the driven member 35. As can be seen from Fig. 13, when the rotation directions of the left drive pulley 37L and the right drive pulley 37R are the same, the driven member 35 is selectively rotated around the first axis A, and when the rotation directions of the left drive pulley 37L and the right drive pulley 37R are opposite to each other, the driven member 35 is selectively rotated around the second axis B.

[0087] In this way, the power transmission device 1 can rotate the driven member 35 independently around the first axis A and the second axis B by controlling the rotation directions of the pair of left and right drive pulleys 37. Because the palm portion 11 is connected to the lower arm 9 via the driven member 35, the palm portion 11 is connected to the lower arm 9 so as to be rotatable around the first axis A and around the second axis B that is perpendicular to the first axis A. In other words, the power transmission device 1 realizes a wire-driven driving device 7 that can rotate the palm portion 11, which is connected to the lower arm 9 so as to be rotatable in two directions, the first axis A and the second axis B, in each of these directions.

[0088] In particular, in the power transmission device 1 according to the present invention, the torques generated by the left actuator 31L and the right actuator 31R are added together and output to the palm portion 11, so that the magnitude of the torque required for each actuator 31 can be reduced compared to when driving with a single actuator 31, and the actuators 31 can be made smaller.

[0089] By using a wire-driven system, the actuator 31 can be provided on the base end side of the lower arm 9, away from the first axis A and the second axis B. Therefore, there is no need to provide the actuator 31 in the wrist portion, and the wrist portion can be configured to be lightweight and compact. By reducing the weight of the wrist portion, the load applied to the left actuator 31L and the right actuator 31R is reduced, and the left actuator 31L and the right actuator 31R can be made smaller. Furthermore, by reducing the weight of the wrist portion, the load torque of the actuator 31 on the base side of the arm (shoulder or elbow) can be reduced, and therefore the actuators 31 that drive the shoulder joint and elbow joint can be made smaller and lighter.

[0090] In this embodiment, the left and right horizontal idler pulleys 49HL and 49HR have the same shape, and the vertical idler pulley 49V also has the same shape. Therefore, the torques generated by the drive pulley 37 on the intermediate member 33 and the driven member 35 are equal, regardless of the left or right direction or the direction of rotation. Therefore, the torques generated on the driven member 35 are easily canceled out, which simplifies the drive operation of the left and right drive pulleys 37 and makes it easier to control the actuator 31.

[0091] The driven pulley 35A is connected to the palm portion 11, and the palm portion 11 is provided with fingers 13 (assisted driven portions) that are driven by finger driving wires 19 (linear members). A through hole 43 is provided in the intermediate member 33, and the finger driving wires 19 pass through the through hole 43. Because the finger driving wires are arranged to pass through the through hole 43 in this way, the finger driving wires 19 are less likely to protrude from the power transmission device 1, and the driving of the palm portion 11 is less likely to be hindered by the finger driving wires 19.

[0092] In this embodiment, each driven pulley 35A has a groove on its outer circumferential surface, and is rotatably supported by the lower arm 9 so that the groove faces the connection between the palm 11 and the lower arm 9. This allows the finger drive wire to be arranged in a generally straight line facing the palm 11. This allows the finger drive wire 19 to have a small bending angle when configured as a control cable with an outer tube and an inner cable, for example. This reduces friction loss within the control cable and the load on the finger drive device 27, making it possible to make the finger drive device 27 more compact.

[0093] A housing hole 25 is formed in the lower arm 9, and a part (finger driven pulley 27A) of the finger driving device 27 (auxiliary driving device) is housed in the housing hole 25. By housing a part of the finger driving device 27 in the housing hole 25 in this way, the lower arm 9 of the robot can be made compact.

[0094] Although the description of the specific embodiment has been completed above, the present invention is not limited to the above embodiment and can be widely modified and implemented. Furthermore, the specific configuration, arrangement, quantity, and predetermined procedure of each member and part can be appropriately changed without departing from the spirit of the present invention. Meanwhile, not all of the components shown in the above embodiment are necessarily required, and can be selected as appropriate.

[0095] In the above embodiment, the left wire pair 39L and the right wire pair 39R are wound around the intermediate member 33 via the vertical idler pulley 49V, but this is not limited to the embodiment. For example, the intermediate member 33 may be provided with four grooves, and the left wire pair 39L and the right wire pair 39R may be received in the corresponding grooves.

[0096] In the above embodiment, the lower arm 9 is provided with a through-hole 25, and the finger driving device 27 is accommodated in the hole 25. However, the lower arm 9 may be provided with a recess for accommodating the finger driving device 27. This also makes it possible to make the lower arm 9 of the robot more compact.

[0097] In the above embodiment, the power transmission device 1 is provided in a wrist joint, but the present invention is not limited to this. The power transmission device 1 can be applied to any joint of the humanoid robot 3 that rotates around two axes, and specifically, for example, the shoulder joint.

[0098] In the above embodiment, the power transmission device 1 was provided on the robot hand 5, but the power transmission device 1 of the present invention can be applied to any machine equipped with a joint that rotates on two axes (for example, a welding machine tool, etc.).

[0099] In the above embodiment, an example has been described in which the finger drive wire 19 for driving the finger 13 is passed through the through hole 43 provided in the intermediate member 33, but this is not limiting. For example, the member passed through the through hole 43 may be any member (linear member) configured to have a linear shape. For example, the linear member may be a tube for driving other mechanisms including the finger 13 (for example, a supply tube for supplying air, fuel, etc.), a signal line, wiring for power supply, etc. [Explanation of symbols]

[0100] 1: Power transmission device 7: Drive unit 9: Lower arm (base) 23A: Through hole 25: Storage hole 33: Intermediate member 35: driven member 37: Drive pulley 39: Wire 39L: Left wire pair (left wire) 39R: Right wire pair (right wire) 41HS: Side view 41VS: Vertical side 43:Through hole 49: Idler pulley 49H: Horizontal idler pulley 49V: Vertical idler pulley (idler pulley) A: 1st axis B: 2nd axis P: Virtual surface

Claims

1. a base having a pair of left and right drive pulleys that can rotate independently; an intermediate member supported on the base so as to be rotatable about a first axis; a driven member supported by the intermediate member so as to be rotatable about a second axis perpendicular to the first axis, A pair of left wires are wound around the left driving pulley and the left driven member in opposite directions and fixed to each other, A pair of right wires are wound around the right drive pulley and the right driven member in opposite directions and fixed to each other, the left wire and the right wire are wound around the intermediate member so as to apply a torque that rotates the driven member about the first axis by rotation of the corresponding drive pulley; When the torque about the second axis imparted to the driven member via the left wire by rotation of the left driving pulley and the torque about the second axis imparted to the driven member by the right wire by rotation of the right driving pulley are in the same direction, the torque about the first axis imparted from the left wire to the driven member and the torque about the first axis imparted from the right wire to the driven member are in opposite directions, A power transmission device in which, when the torque about the second axis imparted to the driven member via the left wire due to rotation of the left drive pulley and the torque about the second axis imparted to the driven member by the right wire due to rotation of the right drive pulley are in opposite directions, the torque about the first axis imparted from the left wire to the driven member and the torque about the first axis imparted from the right wire to the driven member are in the same direction.

2. a torque about the first axis imparted to the driven member when tension is applied to one of the left wires is in an opposite direction to a torque about the first axis imparted to the driven member when tension is applied to the other of the left wires; and 2. The power transmission device according to claim 1, wherein a torque about the first axis imparted to the driven member when tension is applied to one of the right wires is in an opposite direction to a torque about the first axis imparted to the driven member when tension is applied to the other of the right wires.

3. 3. The power transmission device according to claim 1, wherein the intermediate member includes a pair of left idler pulleys around which the left wire is wound, and a pair of right idler pulleys around which the right wire is wound, respectively.

4. the intermediate member has a pair of lateral side surfaces that are perpendicular to the first axis and face in directions away from each other, and a pair of longitudinal side surfaces that are perpendicular to the lateral side surfaces and face in directions away from each other, The vertical side surface has 4. The power transmission device according to claim 3, wherein the pair of left idler pulleys and the pair of right idler pulleys are respectively disposed symmetrically with respect to an imaginary plane that is perpendicular to the vertical side surface and includes the first axis, and each is supported by the vertical side surface so as to be rotatable about an axis parallel to the vertical side surface.

5. a pair of lateral idler pulleys that are coaxial with the first shaft and rotatable on the first shaft; The power transmission device according to any one of claims 1 to 4, wherein the left wire and the right wire are each wound around the corresponding lateral idler pulley between the drive pulley and the driven member.

6. a pair of lateral idler pulleys that are coaxial with the first shaft and rotatable on the first shaft; the left wire and the right wire are wound around the corresponding lateral idler pulley between the drive pulley and the driven member, The pair of left idler pulleys and the pair of right idler pulleys all have the same shape, 5. A power transmission device according to claim 3, wherein one of said lateral idler pulleys has the same shape as the other of said lateral idler pulleys.

7. 7. The power transmission device according to claim 1, wherein the intermediate member is provided with a through hole.

8. The driven member is provided with an assisted driven portion that is driven by a linear member. The power transmission device according to claim 7, wherein the linear member passes through the through hole.

9. 9. The power transmission device according to claim 8, wherein the base is formed with a recess or a housing hole for housing an auxiliary driving device that drives the assisted driven part.

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