Robot wrist

Abstract

To provide a robot wrist that is compact and has a large stroke in a straight advance direction.SOLUTION: A robot wrist 4 comprises a first base 41, a second base 42, a link mechanism 6 and a first actuator 51. The link mechanism 6 includes a Chebyshev link mechanism 60 that connects the second base 42 to the first base 41 so that the second base can move linearly in a straight advance direction Z. The Chebyshev link mechanism 60 has: an original driving node 61 connected to the first base 41 rotatably around a drive shaft D and rotationally driven; a driven node 62 connected to the first base 41 rotatably around a shaft parallel to the drive shaft D; and intermediate nodes 63 connected to the original driving node 61 and the driven node 62 respectively rotatably around the shaft parallel to the drive shaft D. The second base 42 is connected to the intermediate node 63.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, robot arms with connected hands have been known. For example, in the robot arm described in Patent Document 1, the hand is moved linearly from a stopped state of the robot arm. This allows the hand to access a workpiece or the like by simply moving the hand without moving the robot arm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-255207 A Summary of the Invention [Problem to be solved by the invention]

[0004] The reach of the hand is expanded according to the linear stroke of the hand. Therefore, it is conceivable to configure the robot wrist that connects the robot arm and the hand so that the hand can move linearly. However, in order to increase the linear stroke of the hand, there is a risk that the robot wrist will become larger.

[0005] The technology disclosed herein has been made in consideration of the above points, and has an object to provide a robot wrist that is compact and has a large stroke in the linear direction. [Means for solving the problem]

[0006] The robot wrist of the present disclosure comprises a first base attached to a robot arm, a second base to which a hand is attached, a link mechanism movably connecting the second base to the first base, and a first actuator driving the link mechanism, wherein the link mechanism includes a Chebyshev link mechanism connecting the second base to the first base so as to be linearly movably in a predetermined rectilinear direction, the Chebyshev link mechanism having a driver connected to the first base rotatably about a predetermined drive axis and driven to rotate, a follower connected to the first base rotatably about an axis parallel to the drive axis, and an intermediate joint connected to each of the driver and follower rotatably about an axis parallel to the drive axis, and the second base is connected to the intermediate joint. Effect of the Invention

[0007] According to the robot wrist described above, it is possible to provide a robot wrist that is compact and has a large stroke in the linear movement direction. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a robot. [Diagram 2] FIG. 2 is a schematic diagram for explaining the movement of the wrist and hand within a container during a transfer operation. [Diagram 3] FIG. 3 is a perspective view of the wrist in a basic state. [Figure 4] FIG. 4 is a side view of the wrist in a base state. [Diagram 5] FIG. 5 is a plan view of the list in its base state. [Figure 6] FIG. 6 is a cross-sectional view of the wrist taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a side view of the wrist in the advanced state. [Figure 8] FIG. 8 is a side view of the wrist when the hand is advanced as far as possible in the straight-ahead direction. [Figure 9]FIG. 9 is a perspective view of the wrist when the hand is advanced to the maximum in the straight-advance direction. [Figure 10] FIG. 10 is a side view of the wrist after pitch motion. [Figure 11] FIG. 11 is a side view of the wrist 4 when the hand is advanced to the maximum in the straight-ahead direction and the pitch angle is 90 degrees. [Figure 12] FIG. 12 is a perspective view of the wrist after the roll motion. [Figure 13] FIG. 13 is a front view of the wrist with the link mechanism rotated about the roll axis. [Figure 14] FIG. 14 is a side view of the wrist after yaw motion. [Figure 15] FIG. 15 is a front view of a hand and wrist positioned above a container. [Figure 16] FIG. 16 is a front view of the hand and wrist after a roll motion. [Figure 17] FIG. 17 is a front view of the hand and wrist after a straight movement. [Figure 18] FIG. 18 is a side view of the hand and wrist before yaw operation when picking up adjacent workpieces. [Figure 19] FIG. 19 is a side view of the hand and wrist after a yaw operation when picking up a plurality of adjacent workpieces. [Figure 20] FIG. 20 is a side view of the hand and wrist when the hand is retreated in the linear direction while gripping a workpiece. [Figure 21] FIG. 21 is a side view of the hand and wrist in which the hand gripping a workpiece is rotated around the pitch axis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, exemplary embodiments will be described in detail with reference to the drawings. In the present disclosure, "parallel," "orthogonal," or "identical" includes not only "strictly parallel," "orthogonal," or "identical," but also "substantially parallel," "orthogonal," or "identical."

[0010] FIG. 1 is a schematic diagram showing a robot 1. The robot 1 performs a transfer operation. Specifically, the robot 1 takes out a workpiece W from a first container C1 placed on a shelf S, and transfers the workpiece W to a second container C2. The first container C1 is a source container that accommodates the workpiece W. The second container C2 is a destination container that accommodates the workpiece W.

[0011] The shelf S has a plurality of shelf boards s1 arranged at intervals in the vertical direction. The first container C1 is placed on the shelf boards s1. On the shelf S, a working space H into which the robot arm 2 can enter is present between the first container C1 and the shelf board s1 located above the first container C1.

[0012] The robot 1 includes a cart 11, an elevator 12 placed on the cart 11, a robot arm 2 attached to the elevator 12, a robot wrist 4 attached to the tip of the robot arm 2, and a hand 3 attached to the robot wrist 4. Hereinafter, the robot wrist 4 will also be referred to simply as "wrist 4".

[0013] The robot 1 moves by traveling on a cart 11. The cart 11 is, for example, an AGV (Automated Guided Vehicle). In this example, the cart 11 carries a second container C2.

[0014] The elevator 12 raises and lowers the robot arm 2 and rotates it. In this example, the elevator 12 has a support 12a. The support 12a has an axis extending in the vertical direction. The axis of the support 12a is also referred to as the lifting axis U. The support 12a is attached to the cart 11 so as to be rotatable around the lifting axis U. The support 12a supports the robot arm 2 so as to be movable along the lifting axis U. The elevator 12 has a linear actuator that moves the robot arm 2 along the lifting axis U, and a rotary actuator that rotates the support 12a around the lifting axis U. That is, the elevator 12 moves the robot arm 2 along the lifting axis U by the linear actuator. The elevator 12 rotates the support 12a, and therefore the robot arm 2, around the lifting axis U by the rotary actuator.

[0015] The robot arm 2 is a linear-acting telescopic arm. The robot arm 2 telescopically extends in the direction of a predetermined advance / retract axis V. The robot arm 2 moves the wrist 4 and the hand 3 by telescopically extending. Specifically, the robot arm 2 has multiple cylindrical arm housings 21. The axis of each arm housing 21 coincides with the advance / retract axis V. The multiple arm housings 21 are nested. The multiple arm housings 21 are capable of moving relative to one another in the direction of the advance / retract axis V. The robot arm 2 has a linear actuator that moves the multiple arm housings 21 relative to one another. The multiple arm housings 21 move relatively in the direction of the advance / retract axis V, causing the robot arm 2 to extend and contract in the direction of the advance / retract axis V.

[0016] The robot arm 2 is supported by the elevator 12 with the advance / retract axis V intersecting the lift axis U. Specifically, the advance / retract axis V is perpendicular to the lift axis U. The advance / retract axis V may be disposed at a skewed position with respect to the lift axis U.

[0017] The wrist 4 moves the hand 3 relative to the robot arm 2. The wrist 4 is attached to the tip of the robot arm 2.

[0018] The hand 3 holds the workpiece W. The form of holding by the hand 3 is arbitrary. For example, holding by the hand 3 may be by gripping or suction. In this example, the hand 3 grips the workpiece W. The hand 3 has a hand body 31 and a plurality of fingers 32 attached to the hand body 31. The hand 3 opens and closes the plurality of fingers 32.

[0019] A brief description will now be given of the transfer operation performed by the robot 1. Fig. 2 is a schematic diagram for explaining the movement of the wrist 4 and hand 3 within a container during the transfer operation. As shown in Fig. 1, the robot 1 moves to a position facing the shelf S by traveling the cart 11. At this time, the elevator 12 moves the robot arm 2 so that the hand 3 is positioned at a predetermined entry start position. The entry start position is a position where the hand 3 faces the working space H between the target first container C1 and the shelf board s1 positioned above it.

[0020] Next, the robot 1 extends the robot arm 2, thereby causing the robot arm 2 to enter the working space H. As a result, the wrist 4 and the hand 3 enter the working space H. The hand 3 is moved to a position above the workpiece W to be picked up in the first container C1.

[0021] 2, the robot 1 moves the hand 3 into the first container C1. For example, the robot 1 moves the hand 3 via the wrist 4 in a direction intersecting with the forward / backward axis V of the robot arm 2, and causes the hand 3 to enter the first container C1. Then, the robot 1 grips the workpiece W to be picked up with the fingers 32 of the hand 3.

[0022] When the gripping is completed, the robot 1 moves the hand 3 above the first container C1, i.e., to the working space H. From that state, the robot 1 retracts the robot arm 2 and moves the hand 3 together with the workpiece W back from the working space H.

[0023] Thereafter, the elevator 12 rotates and raises and lowers the robot arm 2 to move the hand 3 above the second container C2. The robot 1 moves the hand 3 into the second container C2. The robot 1 places the workpiece W in the second container C2 by releasing the grip of the workpiece W by the fingers 32 of the hand 3.

[0024] In this way, the workpiece W to be picked is transferred from the first container C1 to the second container C2.

[0025] =List= Next, the wrist 4 will be described in detail. Fig. 3 is a perspective view of the wrist 4 in a basic state. Fig. 4 is a side view of the wrist 4 in a basic state. Fig. 5 is a plan view of the wrist 4 in a basic state. Note that the hand 3 is omitted in Figs. 3 and 5.

[0026] The wrist 4 linearly moves the hand 3 in a predetermined linear direction Z. The wrist 4 includes a first base 41 attached to the robot arm 2, a second base 42 to which the hand 3 is attached, a link mechanism 6 that movably connects the second base 42 to the first base 41, and a first actuator 51 that drives the link mechanism 6. The wrist 4 is attached to the robot arm 2 via the first base 41. The hand 3 is attached to the wrist 4 via the second base 42. The first base 41 and the second base 42 are connected to each other via the link mechanism 6. The first actuator 51 drives the link mechanism 6, thereby causing the second base 42 to move relative to the first base 41. In other words, the hand 3 moves relative to the robot arm 2.

[0027] The link mechanism 6 includes a Chebychev link mechanism 60 that connects the second base 42 to the first base 41 so as to be linearly movable in a predetermined translational direction Z. The first actuator 51 drives a link included in the Chebychev link mechanism 60 to linearly move the second base 42, i.e., the hand 3, in the translational direction Z.

[0028] Here, the linear movement of the second base 42 by the Chebyshev link mechanism 60 is not limited to a strictly linear movement, and may be a substantially linear movement. In this example, the linear movement of the second base 42 is a substantially linear movement along the linear direction Z. The linear direction Z is a direction intersecting with the advance / retract axis V of the robot arm 2, and specifically, a direction perpendicular to the advance / retract axis V. In other words, the wrist 4 linearly moves the hand 3 via the link mechanism 6 in a direction intersecting with the advance / retract direction of the robot arm 2.

[0029] The wrist 4 also performs pitch, roll, and yaw movements in addition to the linear movement. Specifically, the wrist 4 further includes a second actuator 52 that rotates the second base 42 around a pitch axis P extending in a direction intersecting the linear direction Z, and a pitch transmission mechanism 8 that transmits the driving force of the second actuator to the second base 42. The wrist 4 further includes a third actuator 53 that rotates the second base 42 around a roll axis R extending in a direction intersecting both the direction of the pitch axis P and the linear direction Z. The wrist 4 further includes a fourth actuator 54 that rotates the hand 3 around a predetermined yaw axis Y, and a yaw transmission mechanism 79 that transmits the driving force of the fourth actuator 54. The basic state of the wrist 4 is a reference state in the linear movement, pitch movement, roll movement, and yaw movement.

[0030] =First Base= The first base 41 has a base body 43 attached to the robot arm 2, and a rotating body 44 rotatably connected to the base body 43. The base body 43 is fixed to the tip of the robot arm 2 (in this example, the end opposite the elevator 12). The rotating body 44 is connected to the base body 43 via a bearing so as to be rotatable around a roll axis R. In this example, the roll axis R is parallel to the advance / retract axis V, and more specifically, is aligned in a straight line with the advance / retract axis V. A link mechanism 6 is attached to the rotating body 44.

[0031] =Second Base= The second base 42 has a base body 45 attached to the link mechanism 6, and a rotating body 46 rotatably connected to the base body 45. The rotating body 46 is connected to the base body 45 via a bearing so as to be rotatable around the yaw axis Y. As shown in FIG. 4, the hand 3 is attached to the rotating body 46. When the rotating body 46 rotates relative to the base body 45, the hand 3 also rotates together with the rotating body 46 around the yaw axis Y relative to the base body 45.

[0032] = Link mechanism = The link mechanism 6 includes a pair of a first link mechanism 6A and a second link mechanism 6B arranged to face each other. Each of the first link mechanism 6A and the second link mechanism 6B movably connects the second base 42 to the first base 41. Each of the first link mechanism 6A and the second link mechanism 6B includes a Chebyshev link mechanism 60. The first link mechanism 6A and the second link mechanism 6B have the same configuration. The first link mechanism 6A and the second link mechanism 6B perform the same operation to move the second base 42.

[0033] The link mechanism 6 is connected to the first base 41 so as to be rotatable about the roll axis R. More specifically, the link mechanism 6 is attached to a rotating body 44 of the first base 41. When the rotating body 44 rotates about the roll axis R, the link mechanism 6 also rotates about the roll axis R. When the link mechanism 6 rotates about the roll axis R, the hand 3 also rotates about the roll axis R together with the second base 42.

[0034] = Chebyshev link mechanism = The Chebyshev link mechanism 60 has a driver 61, a driven link 62, and an intermediate link 63. The driver 61 is connected to the first base 41 rotatably around a predetermined drive axis D and is driven to rotate. The driven link 62 is connected to the first base 41 rotatably around an axis parallel to the drive axis D. The intermediate link 63 is connected to each of the driver 61 and the driven link 62 rotatably around an axis parallel to the drive axis D. In detail, a shaft 65 is supported on the first base 41 rotatably around its axis. The rotation axis of the shaft 65 is the drive axis D. The driver 61 is connected to the shaft 65 non-rotatably. That is, the driver 61 is connected to the first base 41 rotatably around the drive axis D via the shaft 65. The driver 61 and the shaft 65 are connected to the rotor 44 of the first base 41. The follower 62 is connected to the rotating body 44 of the first base 41. The rotation axis of the follower 62 is separated from the drive axis D of the driver 61 in a direction parallel to the linear direction Z. The intermediate link 63 is connected to the second base 42, more specifically, the base body 45. The follower 62 is connected to a portion of the intermediate link 63 between a portion to which the driver 61 is connected and a portion to which the second base 42 is connected. When the driver 61 is rotationally driven, the follower 62 and the intermediate link 63 move in conjunction with each other, and the second base 42 moves.

[0035] In the Chebyshev link mechanism 60, the link length of each link is appropriately set, so that the connection portion of the intermediate link 63 to the second base 42 moves approximately linearly in response to the rotation of the driver 61. Specifically, if the link length of the driver 61 is 1, the link length of the follower 62 is 2.5, the distance between the connection portion of the driver 61 and the connection portion of the follower 62 in the intermediate link 63 is 2.5, the distance between the connection portion of the follower 62 and the connection portion of the second base 42 in the intermediate link 63 is 2.5, and the distance between the drive axis D of the driver 61 and the rotation axis of the follower 62 is 2. As a result, when the driver 61 is rotationally driven, the connection portion of the intermediate link 63 to the second base 42, i.e., the second base 42, moves linearly. The movement direction of the second base 42 substantially coincides with the rectilinear direction Z.

[0036] The first link mechanism 6A and the second link mechanism 6B face each other in the direction of the drive shaft D. That is, the opposing direction of the first link mechanism 6A and the second link mechanism 6B coincides with the direction of the drive shaft D. In the direction of the drive shaft D, the driver 61 of the first link mechanism 6A faces the driver 61 of the second link mechanism 6B, the follower 62 of the first link mechanism 6A faces the follower 62 of the second link mechanism 6B, and the intermediate link 63 of the first link mechanism 6A faces the intermediate link 63 of the second link mechanism 6B.

[0037] More specifically, each of the two joints connected to each other in the link mechanism overlaps in the direction of the drive axis D at the joint, and therefore are disposed at offset positions in the direction of the drive axis D. As shown in FIG. 5, the driving joint 61 of the first link mechanism 6A is disposed on the inside of the intermediate joint 63 of the first link mechanism 6A in the opposing direction between the first link mechanism 6A and the second link mechanism 6B. The driving joint 61 of the second link mechanism 6B is disposed on the inside of the intermediate joint 63 of the second link mechanism 6B in the opposing direction between the first link mechanism 6A and the second link mechanism 6B. That is, the driving joint 61 of the first link mechanism 6A and the driving joint 61 of the second link mechanism 6B are disposed between the intermediate joint 63 of the first link mechanism 6A and the intermediate joint 63 of the second link mechanism 6B. Among the joints of the first link mechanism 6A and the second link mechanism 6B, the intermediate joint 63 of the first link mechanism 6A and the intermediate joint 63 of the second link mechanism 6B are disposed on the outermost sides in the opposing direction.

[0038] The driving link 61 of the first link mechanism 6A and the driving link 61 of the second link mechanism 6B are connected to a common shaft 65.

[0039] The intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B are connected to each other. More specifically, as shown in FIG. 5, a joint 64a connecting the driving link 61 and the intermediate link 63 in the first link mechanism 6A and a joint 64a connecting the driving link 61 and the intermediate link 63 in the second link mechanism 6B are connected to each other. More specifically, the joint 64a of the first link mechanism 6A and the joint 64a of the second link mechanism 6B are connected to each other via a shaft 66 extending parallel to the drive shaft D. The driving link 61 and the intermediate link 63 of the first link mechanism 6A are rotatably connected to one end of the shaft 66. The driving link 61 and the intermediate link 63 of the second link mechanism 6B are rotatably connected to the other end of the shaft 66.

[0040] =First Actuator= The first actuator 51 is an electric motor, specifically, a servo motor. The first actuator 51 is provided with an encoder. The first actuator 51 is attached to the first base 41, more specifically, to the rotating body 44. As shown in FIG. 5, the first actuator 51 is disposed between the first link mechanism 6A and the second link mechanism 6B.

[0041] FIG. 6 is a cross-sectional view of the wrist 4 taken along line VI-VI in FIG. 5. The rotation of the first actuator 51 is transmitted to the Chebyshev link mechanism 60 via a linear transmission mechanism 71. The linear transmission mechanism 71 includes a worm gear. Specifically, the linear transmission mechanism 71 includes a worm 72 attached to the output shaft of the first actuator 51 and a worm wheel 73 connected to the driving link 61 of the Chebyshev link mechanism 60 and meshing with the worm 72. The worm 72 rotates integrally with the output shaft. The worm wheel 73 is attached to the shaft 65 so as not to rotate. That is, the worm wheel 73 is connected to the driving link 61 via the shaft 65.

[0042] When the first actuator 51 operates, the worm 72 rotates. The worm wheel 73 rotates in conjunction with the worm 72, and the shaft 65 rotates integrally with the worm wheel 73. Since the driving link 61 is non-rotatably connected to the shaft 65, the driving link 61 rotates integrally with the shaft 65 about the drive axis D. In this manner, the Chebychev link mechanism 60 is driven by the first actuator 51. Since the driving links 61 of both the first link mechanism 6A and the second link mechanism 6B are connected to the shaft 65, the Chebychev link mechanism 60 of the first link mechanism 6A and the Chebychev link mechanism 60 of the second link mechanism 6B operate integrally.

[0043] =Linear motion= The operation of the wrist 4 by the Chebyshev link mechanism 60 will be described in detail. Fig. 7 is a side view of the wrist 4 in an advanced state. Fig. 8 is a side view of the wrist 4 in a state in which the hand 3 has advanced to the most in the linear direction Z. Fig. 9 is a perspective view of the wrist 4 in a state in which the hand 3 has advanced to the most in the linear direction Z. Note that the hand 3 is omitted in Fig. 9. The advanced state of the wrist 4 is a state in which the wrist 4 has moved from the basic state in the linear direction Z.

[0044] In the Chebyshev link mechanism 60, in a certain section (hereinafter, this section is referred to as a "specific section") in one rotation of the driving link 61, the tip of the intermediate link 63, i.e., the end of the intermediate link 63 opposite to the end to which the driving link 61 is connected, moves substantially linearly. The movement direction of the tip of the intermediate link 63 substantially coincides with the translatory direction Z. Specifically, the tip of the intermediate link 63 moves linearly between a first position and a second position in the translatory direction Z. The second position is farther from the drive axis D of the driving link 61 in the translatory direction Z than the first position. In other words, the movement of the intermediate link 63 toward the second position in the translatory direction Z is a movement away from the drive axis D of the driving link 61, and is also expressed as "advancement." The movement of the intermediate link 63 toward the first position in the translatory direction Z is a movement toward the drive axis D of the driving link 61, and is also expressed as "retreat." In the basic state of the wrist 4, the tip of the intermediate link 63 is located at the first position. The positions of the second base 42, the hand 3, etc. when the tip of the intermediate link 63 is located at the first position are also referred to as the "first position". The positions of the second base 42, the hand 3, etc. when the tip of the intermediate link 63 is located at the second position are also referred to as the "second position". For example, the first position of the hand 3 is the position of the hand 3 when the tip of the intermediate link 63 is located at the first position.

[0045] When the driving link 61 is in the state shown in FIG. 4, the tip of the intermediate link 63 is located at the first position. In addition, in FIGS. 3 and 5, the tip of the intermediate link 63 is located at the first position. When the driving link 61 rotates clockwise (in the direction of the arrow in the figure) from the state shown in FIG. 4, the tip of the intermediate link 63 moves linearly to the second position side (downward in the figure) in the translation direction Z as shown in FIG. 7. When the driving link 61 reaches the state shown in FIG. 8, the tip of the intermediate link 63 reaches the second position in the translation direction Z. When the driving link 61 rotates counterclockwise from the state shown in FIG. 8, the tip of the intermediate link 63 moves linearly to the first position side in the translation direction Z. When the driving link 61 reaches the state shown in FIG. 4, the tip of the intermediate link 63 reaches the first position in the translation direction Z.

[0046] When the driving link 61 further rotates clockwise from the state in Fig. 8 to the state in Fig. 4, the tip of the intermediate link 63 also returns to the first position. However, the trajectory of the tip of the intermediate link 63 at this time is not linear but curved.

[0047] In this way, in a specific section of the rotation of the driver 61, the tip of the intermediate link 63 moves linearly. The second base 42 is connected to the tip of the intermediate link 63, and the hand 3 is attached to the second base 42. That is, the hand 3 moves linearly. By rotating the driver 61 within the specific section, the hand 3 can be moved substantially forward and backward in the linear direction Z. Depending on the direction of rotation of the driver 61 in this specific section, it is determined whether the tip of the intermediate link 63, i.e., the hand 3, moves toward the first position or the second position in the linear direction Z.

[0048] =Pitch transmission mechanism= The second base 42 is connected to the intermediate link 63 so as to be rotatable around the pitch axis P. More specifically, as shown in FIG. 3, the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B face each other in the direction of the drive axis D. The second base 42 is connected to the two intermediate links 63 so as to be rotatable around the pitch axis P. The pitch axis P is parallel to the drive axis D. In other words, the pitch axis P is perpendicular to the plane on which each link of the link mechanism 6 moves. The pitch transmission mechanism 8 is connected to the second base 42. The second base 42 includes a rotor 46 which is rotatable around the yaw axis Y. The yaw axis Y extends in a direction intersecting the direction of the pitch axis P.

[0049] As shown in Fig. 4, the pitch transmission mechanism 8 includes a four-bar link mechanism 80. The four-bar link mechanism 80 is a parallel link mechanism. The intermediate link 63 of the Chebyshev link mechanism 60 functions as a node included in the four-bar link mechanism 80. In this example, as shown in Fig. 5, the pitch transmission mechanism 8 includes a four-bar link mechanism 80 corresponding to the first link mechanism 6A and a four-bar link mechanism 80 corresponding to the second link mechanism 6B. The four-bar link mechanism 80 corresponding to the first link mechanism 6A and the four-bar link mechanism 80 corresponding to the second link mechanism 6B have the same configuration.

[0050] 4, the four-bar link mechanism 80 includes a first four-bar link mechanism 81 connected to the second base 42, and a second four-bar link mechanism 82 connected to the first four-bar link mechanism 81 and driven by the second actuator 52. The intermediate link 63 of the Chebychev link mechanism 60 functions as a link included in the first four-bar link mechanism 81, and the driven link 62 of the Chebychev link mechanism 60 functions as a link included in the second four-bar link mechanism 82.

[0051] Specifically, the first four-link link mechanism 81 includes a first fixed link 83, a first driver link 84 connected to the first fixed link 83 rotatably around an axis parallel to the pitch axis P, a first follower link 85 connected to the first fixed link 83 rotatably around an axis parallel to the pitch axis P, and a first intermediate link 86 connected to each of the first driver link 84 and the first follower link 85 rotatably around an axis parallel to the pitch axis P. The first fixed link 83 is the intermediate link 63 of the Chebyshev link mechanism 60. The first follower link 85 is fixed to the second base 42. More specifically, the first follower link 85 is a part of the base body 45 of the second base 42. The first intermediate link 86 is disposed at a position opposite to the first fixed link 83. The first four-link link mechanism 81 is a parallel link mechanism. The four joints connecting the first fixed link 83, the first driving link 84, the first driven link 85 and the first intermediate link 86 are disposed at the vertices of a substantially parallelogram.

[0052] The second four-bar link mechanism 82 includes a second fixed section 87, a second driver section 88 connected to the second fixed section 87 rotatably around an axis parallel to the pitch axis P, a second follower section 89 connected to the second fixed section 87 rotatably around an axis parallel to the pitch axis P, and a second intermediate section 810 connected to each of the second driver section 88 and the second follower section 89 rotatably around an axis parallel to the pitch axis P. The second fixed section 87 is the follower section 62 of the Chebyshev link mechanism 60. The second intermediate section 810 is disposed at a position opposite to the second fixed section. The second four-bar link mechanism 82 is a parallel link mechanism. The four joints connecting the second fixed section 87, the second driver section 88, the second follower section 89, and the second intermediate section 810 are disposed substantially at the vertices of a parallelogram.

[0053] 4, straight lines defining the link lengths of each joint of the first four-joint link mechanism 81 and the second four-joint link mechanism 82 are shown by dashed lines. The same applies to FIGS.

[0054] The second follower 89 is connected to the first driver 84. The second follower 89 is connected to the first driver 84 via a connecting joint 811. When the second follower 89 moves, the first driver 84 moves in conjunction with the second follower 89. More specifically, both the first driver 84 and the second follower 89 are connected to the connecting portion between the follower 62 and the intermediate joint 63. The first driver 84, the second follower 89, and the connecting joint 811 are integrally formed. The mutual positional relationship between the first driver 84, the second follower 89, and the connecting joint 811 is fixed. In this example, the first driver 84, the second follower 89, and the connecting joint 811 are formed of a substantially triangular plate. When the second follower 89 moves, the first driver 84 and the connecting joint 811 move in conjunction with the second follower 89.

[0055] The second driving link 88 is rotationally driven by the second actuator 52. As shown in FIG. 6, a shaft 812, which is rotationally driven by the second actuator 52, is connected to the second driving link 88. More specifically, the shaft 812 is supported on the first base 41 so as to be rotatable about its axis. The rotation axis E of the shaft 812, i.e., the axis, is parallel to the drive axis D. The second driving link 88 is non-rotatably connected to the shaft 812. That is, the second driving link 88 is connected to the first base 41 via the shaft 812 so as to be rotatable about the rotation axis E. The second driving link 88 and the shaft 812 are connected to the rotor 44 of the first base 41. The follower link 62 is connected to the shaft 812 so as to be rotatable about the rotation axis E. That is, the follower link 62 is rotatably connected to the first base 41 via the shaft 812 and is also rotatably connected to the second driving link 88.

[0056] When the shaft 812 is driven to rotate, the second driving link 88 rotates integrally with the shaft 812. On the other hand, the follower 62 does not rotate integrally with the shaft 812. When the second driving link 88 rotates, the second intermediate link 810 and the second follower 89 move in conjunction with the rotation of the second driving link 88. When the second follower 89 moves, the first driving link 84 of the first four-link link mechanism 81 rotates in conjunction with the second follower 89. When the first driving link 84 rotates, the first intermediate link 86 and the first follower 85 move in conjunction with the rotation of the first driving link 84. Since the first follower 85 is formed integrally with the second base 42, the second base 42 rotates around the pitch axis P. Even if the second driving link 88 rotates, the first fixed link 83 and the second fixed link 87, i.e., the Chebyshev link mechanism 60, are not affected.

[0057] In this manner, when the second driving link 88 is rotationally driven, the second base 42 and the hand 3 rotate about the pitch axis P without affecting the Chebyshev link mechanism 60.

[0058] =Second Actuator= The second actuator 52 is an electric motor, specifically, a servo motor. The second actuator 52 is provided with an encoder. As shown in FIG. 5, the second actuator 52 is attached to the first base 41, more specifically, to the rotating body 44. The second actuator 52 is disposed between the first link mechanism 6A and the second link mechanism 6B.

[0059] The rotation of the second actuator 52 is transmitted to the four-bar linkage mechanism 80 via a worm gear. Specifically, as shown in FIG. 6, a worm 74 is attached to the output shaft of the second actuator 52. The worm 74 rotates integrally with the output shaft. A worm wheel 75 is connected to a second driving link 88 of the four-bar linkage mechanism 80. The worm wheel 75 is attached to a shaft 812 so as not to rotate. That is, the worm wheel 75 is connected to the second driving link 88 via the shaft 812. The worm 74 and the worm wheel 75 mesh with each other.

[0060] When the second actuator 52 operates, the worm 74 rotates. The worm wheel 75 rotates in conjunction with the worm 74, and the shaft 812 rotates integrally with the worm wheel 75. Since the second driving link 88 is non-rotatably connected to the shaft 812, the second driving link 88 rotates integrally with the shaft 812 around the rotation axis E. In this manner, the four-bar linkage 80 is driven by the second actuator 52. Since the second driving link 88 of the four-bar linkage 80 corresponding to the first linkage 6A and the second driving link 88 of the four-bar linkage 80 corresponding to the second linkage 6B are connected to the shaft 812, the second driving links 88 of the two four-bar linkages 80 operate integrally.

[0061] =Pitch movement= Next, the pitch movement of the wrist 4 will be described. FIG. 10 is a side view of the wrist 4 after the pitch movement. The wrist 4 in FIG. 10 rotates the hand 3 around the pitch axis P from the basic state in FIG. 4. In this example, the pitch angle is set to 0 degrees when the fingers 32 extend in the rectilinear direction Z, that is, when the yaw axis Y faces the rectilinear direction Z. The direction in which the tip of the finger 32 rotates toward the opposite side to the first base 41 from the state in which the pitch angle is 0 degrees is set to positive. The hand 3 in FIG. 10 has rotated approximately 90 degrees around the pitch axis P.

[0062] When the Chebyshev link mechanism 60 is not moving, the follower 62 (i.e., the second fixed link 87) and the intermediate link 63 (i.e., the first fixed link 83) do not move. When the second driver 88 is rotationally driven by the second actuator 52, the second intermediate link 810 and the second follower 89 move in conjunction with the second driver 88. Since the relative positional relationship between the first driver 84 and the second follower 89 is unchanged, the first driver 84 rotates in conjunction with the movement of the second follower 89. When the first driver 84 rotates, the first intermediate link 86 and the first follower 85 move in conjunction with the first driver 84. The first follower 85 rotates around the pitch axis P. The first follower 85 is formed integrally with the second base 42, and the hand 3 is attached to the second base 42. That is, the hand 3 rotates around the pitch axis P. The pitch angle, which is the angle of the second base 42 around the pitch axis P, is adjusted by the rotation angle of the second driving link 88.

[0063] When the Chebychev link mechanism 60 operates, the follower 62 and the intermediate link 63 move, and the four-link link mechanism 80 also moves. However, when the second driver 88 is not rotationally driven, the angle of the first follower 85 does not change and the pitch angle of the hand 3 is maintained, as shown in Figs. 4, 7, and 8. In other words, the pitch transmission mechanism 8 maintains the pitch angle of the second base 42 around the pitch axis P when the second base 42 moves in the rectilinear direction Z via the Chebychev link mechanism 60. The attitude of the first driver 84, which is a node facing the first follower 85, which is a node integral with the second base 42, is maintained and does not change during the operation of the Chebychev link mechanism 60.

[0064] Specifically, since the second four-bar link mechanism 82 is a parallel link mechanism, the angle between the second driver 88 and the second follower 89 facing each other does not change in Figs. 4, 7, and 8. In other words, if the second driver 88 does not rotate, the angle of the second follower 89 does not change even if the second follower 89 moves. In addition, since the second follower 89 and the first driver 84 are integrally connected, the relative positional relationship between the second follower 89 and the first driver 84 does not change. In other words, if the angle of the second follower 89 does not change, the angle of the first driver 84 does not change even if the first driver 84 moves. Furthermore, since the first four-bar link mechanism 81 is a parallel link mechanism, the angle between the first driver 84 and the first follower 85 facing each other does not change. In other words, if the angle of the first driver 84 does not change, the angle of the first follower 85 does not change even if the first follower 85 moves. In short, even if the second follower 89, the first driver 84, and the first follower 85 move in response to the operation of the Chebyshev link mechanism 60, unless the second driver 88 rotates, the angles of the second follower 89, the first driver 84, and the first follower 85 do not change.

[0065] In other words, the pitch angle of the hand 3 depends on the rotation angle of the second driving link 88 and is not affected by the state of the Chebyshev link mechanism 60. Whether the Chebyshev link mechanism 60 is stopped or in operation, when the second driving link 88 is rotationally driven, the pitch angle of the hand 3 changes according to the rotation angle of the second driving link 88. Whether the Chebyshev link mechanism 60 is stopped or in operation, when the second driving link 88 is not rotating, the pitch angle of the hand 3 is maintained.

[0066] In the pitch transmission mechanism 8, the shaft 812 is connected to the second driving link 88. Therefore, as shown in FIG. 11, depending on the state of the pitch transmission mechanism 8, the second intermediate link 810 approaches the shaft 812. FIG. 11 is a side view of the wrist 4 when the hand 3 advances most in the rectilinear direction Z and the pitch angle is 90 degrees. The second intermediate link 810 is curved so as to avoid interference with the shaft 812 when it approaches the shaft 812 in conjunction with the second driving link 88. In other words, when the angle between the second driving link 88 and the second fixed link 87 is large, the second intermediate link 810 approaches the shaft 812. The second intermediate link 810 has a curved portion 810a at a portion approaching the shaft 812, which curves so as to be recessed toward the opposite side to the shaft 812. By having the curved portion 810a, the second intermediate link 810 is less likely to interfere with the shaft 812. This increases the range of motion of the second intermediate section 810, and as a result, the range of pitch motion of the wrist 4.

[0067] =Third Actuator= The third actuator 53 is an electric motor, specifically, a servo motor. An encoder is provided in the third actuator 53. The third actuator 53 is attached to the first base 41, more specifically, to the base body 43, as shown in FIG.

[0068] The rotation of the third actuator 53 is transmitted to the rotating body 44 via a roll transmission mechanism 76. The roll transmission mechanism 76 includes a gear train. Specifically, the roll transmission mechanism 76 includes a first gear 77 attached to the output shaft of the third actuator 53 and a second gear 78 attached to the rotating body 44. The first gear 77 rotates integrally with the output shaft. The second gear 78 is attached to the rotating body 44 so as to be non-rotatable. The second gear 78 meshes with the first gear 77.

[0069] =Roll action= Next, the roll motion of the wrist 4 will be described. Fig. 12 is a perspective view of the wrist 4 after the roll motion. In Fig. 12, the link mechanism 6 is rotated around the roll axis R from the basic state of Fig. 4. In this example, the roll angle when the rectilinear direction Z extends vertically and the fingers 32 extend downward from the hand body 31 is set to 0 degrees. The clockwise rotation direction when viewed facing the first base 41 in the direction of the roll axis R is set to positive. The link mechanism 6 in Fig. 12 is rotated about 90 degrees around the roll axis R.

[0070] When the third actuator 53 operates, the first gear 77 rotates. The second gear 78 rotates in conjunction with the first gear 77, and the rotating body 44 rotates integrally with the second gear 78 around the roll axis R. The link mechanism 6 is connected to the rotating body 44. The link mechanism 6 is connected to the second base 42. In this way, the third actuator 53 rotates the second base 42 around the roll axis R. Since the hand 3 is connected to the second base 42, the hand 3 rotates around the roll axis R. The pitch transmission mechanism 8 also rotates integrally with the rotating body 44 around the roll axis R.

[0071] 13 is a front view of the wrist 4 with the link mechanism 6 rotated about the roll axis R. As the link mechanism 6 rotates about the roll axis R, the translation direction Z and the pitch axis P also rotate about the roll axis R. In other words, by rotating the link mechanism 6 about the roll axis R, the orientation of the direction in which the hand 3 moves linearly can be changed, and the orientation of the pitch axis P of the pitch motion of the wrist 4 can also be changed.

[0072] =4th Actuator= The fourth actuator 54 is an electric motor, specifically, a servo motor. The fourth actuator 54 is provided with an encoder. As shown in FIG. 3, the fourth actuator 54 is attached to the second base 42, more specifically, to the base body 45. The fourth actuator 54 is disposed between the first link mechanism 6A and the second link mechanism 6B.

[0073] = Yaw transmission mechanism = The rotation of the fourth actuator 54 is transmitted to the rotor 46 via a yaw transmission mechanism 79. The yaw transmission mechanism 79 includes a transmission belt and a worm gear. Specifically, the shaft 47 is supported on the base body 45 so as to be rotatable about its axis. The yaw transmission mechanism 79 includes a pulley attached to the output shaft of the fourth actuator 54, a pulley attached to the shaft 47, a belt wound around the two pulleys, a worm 710 attached to the shaft 47, and a worm wheel 711 attached to the rotor 46. The worm 710 is non-rotatably attached to the shaft 47 and rotates integrally with the shaft 47. The worm wheel 711 is non-rotatably attached to the rotor 46 and meshes with the worm 710. The yaw axis Y passes through the center of the worm wheel 711.

[0074] When the fourth actuator 54 operates, the shaft 47 rotates via the two pulleys and the belt. The worm 710 rotates together with the shaft 47, and the worm wheel 711 rotates in conjunction with the worm 710. The rotating body 46 rotates integrally with the worm wheel 711.

[0075] = Yaw movement = Next, the yaw movement of the wrist 4 will be described. Fig. 14 is a side view of the wrist 4 after the yaw movement. In Fig. 14, the wrist 4 rotates the hand 3 around the yaw axis Y from the basic state in Fig. 4. In this example, the yaw angle is set to 0 degrees when the opening and closing direction of the fingers 32 is parallel to the roll axis R. The hand 3 in Fig. 14 has rotated approximately 90 degrees around the yaw axis Y.

[0076] When the fourth actuator 54 rotates the rotating body 46 about the yaw axis Y, the hand 3 rotates integrally with the rotating body 46 about the yaw axis Y. When the wrist 4 performs a yaw movement, the opening and closing directions of the fingers 32 change. In FIG. 4, the opening and closing directions of the fingers 32 are parallel to the roll axis R. On the other hand, in FIG. 14, the opening and closing directions of the fingers 32 are perpendicular to the roll axis R.

[0077] Furthermore, since the hand 3 is supported on the second base 42 so as to be rotatable around the yaw axis Y, when the second base 42 moves by roll motion and / or pitch motion, the direction of the yaw axis Y also changes according to the second base 42.

[0078] The wrist 4 thus configured flexibly moves the hand 3 by translational motion, pitch motion, roll motion, and yaw motion. For example, when the robot arm 2 moves the hand 3 to the workspace H, i.e., above the first container C1, the wrist 4 places the hand 3 at a first position in the translational direction Z. At this time, the translational direction Z faces the vertical direction, and the second position is located lower than the first position. The roll axis R faces the horizontal direction. The pitch axis P faces the horizontal direction. The yaw axis Y faces the vertical direction. Since the hand 3 is placed at the first position, the overall size of the hand 3 and the wrist 4 in the translational direction Z is reduced. This makes it easier for the hand 3 and the wrist 4 to enter a narrow space such as the workspace H.

[0079] From this state, the wrist 4 moves the hand 3 toward the second position in the linear direction Z via the Chebyshev link mechanism 60. This causes the hand 3 to move linearly downward and enter the first container C1. When the hand 3 reaches the workpiece W, the hand 3 grasps the workpiece W with the fingers 32.

[0080] After gripping the workpiece W, the wrist 4 moves the hand 3 toward the first position in the linear direction Z via the Chebyshev link mechanism 60. As a result, the hand 3 moves linearly upward and exits the first container C1.

[0081] Thereafter, the robot arm 2 causes the hand 3 and the wrist 4 to withdraw from the working space H. This completes the picking of the workpiece W. At this time, since the hand 3 is disposed at the first position, the overall size of the hand 3 and the wrist 4 in the linear direction Z becomes smaller. This makes it easier for the hand 3 and the wrist 4 to withdraw from a small space such as the working space H.

[0082] With regard to the entry of the hand 3 into the first container C1, the wrist 4 can move the hand 3 in various ways. For example, when the wrist 4 performs a roll motion, the orientation of the linear direction Z changes as shown in FIG. 13. That is, the linear direction Z is inclined with respect to the vertical direction. When the wrist 4 moves the hand 3 from this state toward the second position in the linear direction Z, the hand 3 moves linearly diagonally downward. This makes it possible to adjust the arrival position of the hand 3 without moving the robot arm 2.

[0083] As a result of adjusting the reach position of the hand 3, the reach range of the hand 3 can be expanded. Figures 15, 16, and 17 are explanatory diagrams of the procedure for expanding the reach range of the hand 3. Figure 15 is a front view of the hand 3 and the wrist 4 arranged above the first container C1. Figure 16 is a front view of the hand 3 and the wrist 4 after the roll motion. Figure 17 is a front view of the hand 3 and the wrist 4 after the straight motion. For example, when a workpiece W is arranged near the side wall of the first container C1, if the hand 3 is moved from above in the vertical direction toward the workpiece W, the hand 3 may interfere with the side wall of the first container C1. In such a case, as shown in Figure 15, the hand 3 is arranged at a position away from the side wall of the first container C1. Then, as shown in Figure 16, the wrist 4 rolls to direct the straight direction Z toward the workpiece W near the side wall. Next, as shown in Figure 17, the wrist 4 moves the hand 3 diagonally downward in a straight line by the straight motion. This allows the hand 3 to reach the workpiece W while avoiding interference with the side wall.

[0084] Also, the yaw movement of the wrist 4 can change the orientation of the opening and closing direction of the fingers 32. FIG. 18 is a side view of the hand 3 and the wrist 4 before the yaw movement when picking up adjacent works W. FIG. 19 is a side view of the hand 3 and the wrist 4 after the yaw movement when picking up adjacent works W. For example, the work W may be arranged adjacent to another object, for example, another work W. In such a case, as shown in FIG. 18, if the arrangement direction of the works W and the opening and closing direction of the fingers 32 coincide with each other, the fingers 32 may interfere with the other works W and may not be able to properly grip the target work W. By performing the yaw movement of the wrist 4, the opening and closing direction of the fingers 32 can be made different from the arrangement direction of the works W as shown in FIG. 19. This allows the fingers 32 to properly grip the target work W without interfering with another work W. In this way, by performing the yaw movement of the wrist 4, the opening and closing direction of the fingers 32 can be adjusted according to the surrounding situation of the work W.

[0085] Furthermore, the wrist 4 performs a pitch motion, so that the direction in which the fingers 32 extend can be changed. FIG. 20 is a side view of the hand 3 and the wrist 4 in which the hand 3 is moved backward in the rectilinear direction Z while gripping the workpiece W. FIG. 21 is a side view of the hand 3 and the wrist 4 in which the hand 3 is rotated around the pitch axis P while gripping the workpiece W. For example, the direction of the workpiece W gripped by the fingers 32 can be flexibly changed. The workpiece W gripped by the fingers 32 is usually suspended in the rectilinear direction Z. As shown in FIG. 20, when the workpiece W is large, the overall size of the hand 3 and the wrist 4 including the workpiece W in the rectilinear direction Z becomes large. When the overall size of the hand 3, etc. in the rectilinear direction Z is large, high-precision position control of the hand 3, etc. may be required when the robot arm 2 moves the hand 3, etc. out of the working space H. In some cases, the workpiece W may interfere with the first container C1. In such a case, as shown in FIG. 21, the wrist 4 performs pitching motion so that the yaw axis Y is approximately parallel to the advance / retract axis V, so that the workpiece W extends from the fingers 32 in the direction of the advance / retract axis V. This reduces the overall size of the hand 3 and wrist 4 including the workpiece W in the linear direction Z. As a result, the robot arm 2 can easily move the hand 3 and the like out of the working space H. In addition, the wrist 4 may also adjust the position of the hand 3 in the linear direction Z. Depending on the pitching motion of the wrist 4, the hand 3 or the wrist 4 may protrude in the linear direction Z relative to the robot arm 2 (see FIG. 10). By adjusting the position of the hand 3 in the linear direction Z so that the wrist 4 approaches the advance / retract axis V, the overall size of the robot arm 2, the hand 3, and the wrist 4 in the linear direction Z can be reduced.

[0086] In this way, the wrist 4 flexibly moves the hand 3, so that the hand 3 can appropriately pick up the workpiece W that is placed in a complicated location where the movement of the robot arm 2 is restricted. In other words, it is difficult to move the hand 3 into the first container C1 only by the movement of the robot arm 2. The wrist 4 moves the hand 3 in the linear direction Z, so that the hand 3 can be moved into the first container C1 without moving the robot arm 2. At this time, the wrist 4 moves the hand 3 linearly, so that the position of the hand 3 is easier to manage compared to when the hand 3 moves in a curved line. For example, it is easier to avoid interference between the hand 3 and other objects.

[0087] Furthermore, the link mechanism 6 employs a Chebychev link mechanism 60 for the movement of the hand 3. The linear movement amount by the Chebychev link mechanism 60 is relatively large. In other words, the stroke of the hand 3 in the linear direction Z can be expanded while suppressing the size of the link mechanism 6. The Chebychev link mechanism 60 operates by the driving joint 61 being rotationally driven. Therefore, the Chebychev link mechanism 60 is driven by a motor. For example, the linear movement of the hand 3 can also be realized by a combination of a linear guide and a cylinder or the like. However, a motor has higher controllability than a cylinder or the like. By employing the Chebychev link mechanism 60, the movement of the hand 3 in the linear direction Z can be easily and accurately controlled.

[0088] In addition, the components that are moved by operating the wrist 4 are smaller and lighter than those that are moved by the robot arm 2. Smaller moving components reduce the possibility of interference with other components. Lighter moving components reduce the driving force required for movement and improve controllability. In other words, the wrist 4 has these advantages even in places other than complicated locations.

[0089] The link mechanism 6 supports the second base 42 by a first link mechanism 6A and a second link mechanism 6B that face each other. This improves the support rigidity of the second base 42. Furthermore, the first link mechanism 6A and the second link mechanism 6B are connected by a shaft 66. This improves the rigidity of the link mechanism 6.

[0090] The driving link 61 of the first link mechanism 6A and the driving link 61 of the second link mechanism 6B are connected by a shaft 65 and driven by a common first actuator 51 via the shaft 65. This allows the number of drive sources for the first link mechanism 6A and the second link mechanism 6B to be reduced. Furthermore, as shown in FIG. 3, two driving links 61 are disposed between the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B in the opposing direction of the first link mechanism 6A and the second link mechanism 6B. With this arrangement, the two intermediate links 63 move outside the shaft 65, preventing interference between the intermediate links 63 and the shaft 65.

[0091] 5, two four-bar link mechanisms 80 are disposed between the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B in the opposing direction. This allows the two four-bar link mechanisms 80 to be disposed compactly in the direction of the drive shaft D.

[0092] The first intermediate link 86 and the second intermediate link 810 are arranged in a plane perpendicular to the opposing direction of the first link mechanism 6A and the second link mechanism 6B, that is, in a plane perpendicular to the drive axis D. The first intermediate link 86 is included in the first four-link link mechanism 81, and the second intermediate link 810 is included in the second four-link link mechanism 82. Therefore, the first intermediate link 86 and the second intermediate link 810 hardly overlap in the direction of the drive axis D. Even if the first intermediate link 86 and the second intermediate link 810 are arranged in the same plane perpendicular to the drive axis D, the first intermediate link 86 and the second intermediate link 810 do not interfere with each other. By arranging the first intermediate link 86 and the second intermediate link 810 in the same plane, the size of the four-link link mechanism 80 in the direction of the drive axis D can be reduced.

[0093] Furthermore, the pitch transmission mechanism 8 transmits the driving force of the second actuator 52 to the second base 42 by a link mechanism. Therefore, the configuration of the pitch transmission mechanism 8 can be made smaller than a configuration in which a driving force is transmitted by a cylinder or the like.

[0094] Some of the nodes included in the Chebyshev link mechanism 60 function as nodes included in the pitch transmission mechanism 8. By sharing some of the nodes of the Chebyshev link mechanism 60 with some of the nodes of the pitch transmission mechanism 8, the configuration of the wrist 4 can be simplified.

[0095] Since the four-bar link mechanism 80 included in the pitch transmission mechanism 8 is a parallel link mechanism, it is easy to manage the pitch angle of the second base 42, and therefore the pitch angle of the hand 3. In the four-bar link mechanism 80, the angles of each of the two opposing nodes are substantially the same. Even when the four-bar link mechanism 80 is linked to the Chebyshev link mechanism 60, the pitch angle of the hand 3 can be kept constant by maintaining the angle of the node opposing the node fixed to the second base 42. As a result, the hand 3 can be moved linearly in the rectilinear direction Z without changing the pitch angle of the hand 3.

[0096] The length of the driver 61 of the Chebyshev link mechanism 60 is longer than or equal to the length of any of the first driver 84, the first follower 85, and the second follower 89. This allows the wrist 4 to be deformed compactly in the translatory direction Z. In detail, the Chebyshev link mechanism 60 operates by the rotation of the driver 61. As shown in FIG. 7, the driver 61 may be in a state where it protrudes toward the retreat side in the translatory direction Z from the drive shaft D depending on the rotation angle. Each of the first driver 84, the first follower 85, and the second follower 89 may also be in a state where it faces the retreat side in the translatory direction Z. For example, as shown in FIG. 4, when the tip of the intermediate link 63 is located at the first position, the first driver 84, the first follower 85, and the second follower 89 are located relatively on the retreat side in the translatory direction Z. In this position, the first driver 84, the first follower 85, and the second follower 89 can each be in a state of facing backward in the linear direction Z depending on the angle of the second driver 88 (see Figs. 4 and 10). The length of the driver 61 is longer than or equal to any of the lengths of the first driver 84, the first follower 85, and the second follower 89. Therefore, even if each of the first driver 84, the first follower 85, and the second follower 89 is in a state of being most protruding in the linear direction Z, it will only protrude to approximately the same range as the driver 61 in a state of being most protruding in the linear direction Z. In other words, it is possible to prevent any of the first driver 84, the first follower 85, and the second follower 89 from protruding in the linear direction Z more than the movement range of the driver 61. This makes it possible to prevent the size of the wrist 4 in the backward direction Z from expanding beyond the range of movement of the driving link 61.

[0097] Other Embodiments As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. are appropriately performed. In addition, it is also possible to combine the components described in the above embodiment to form a new embodiment. In addition, among the components described in the attached drawings and detailed description, not only components essential for solving the problem but also components that are not essential for solving the problem in order to exemplify the technology may be included. Therefore, the fact that these non-essential components are described in the attached drawings and detailed description should not immediately be taken to mean that these non-essential components are essential.

[0098] For example, the work performed by the robot 1 is not limited to the transfer work. The robot 1 may perform work such as assembling parts. In the case of the transfer work, the robot 1 may pick up the work W from the second container C2 and place it in the first container C1. The wrist 4 can flexibly move the hand 3 by performing the linear motion, pitch motion, roll motion, and yaw motion as described above when placing the work W. The wrist 4 may also perform the linear motion, pitch motion, roll motion, and yaw motion as described above when picking up the work W from the second container C2. The work W before and after the transfer may not be placed in a container. For example, the work W before the transfer may be placed on a tray, pallet, or conveyor. The work W after the transfer may be placed on a tray, pallet, or conveyor.

[0099] The processing by the hand 3 is not limited to holding a workpiece. For example, the processing by the hand 3 may be machining, welding, painting, etc. The holding of the workpiece by the hand 3 is not limited to gripping, and may be suction or the like.

[0100] Use of the movement of the wrist 4 is not limited to small spaces where the movement of the robot arm 2 is restricted. Even in an environment where the movement of the robot arm 2 is not restricted, operating the hand 3 by the wrist 4 has the effect of reducing the driving force and improving controllability.

[0101] The pitch, roll, and yaw motions of the wrist 4 are not essential. The wrist 4 only needs to move the hand 3 linearly via at least the Chebyshev link mechanism 60. For example, the wrist 4 can combine at least one of the pitch, roll, and yaw motions with the linear motion of the Chebyshev link mechanism 60.

[0102] The link mechanism 6 includes two link mechanisms, a first link mechanism 6A and a second link mechanism 6B. However, the link mechanism 6 may include only one of the first link mechanism 6A and the second link mechanism 6B. Alternatively, the link mechanism 6 may include three or more link mechanisms.

[0103] Regarding the roll operation, the rotating body 44 is connected to the base main body 43 of the first base 41 so as to be rotatable about the roll axis R. This causes the link mechanism 6, the second base 42, and the hand 3 to rotate about the roll axis R. However, the configuration related to the roll operation is not limited to this. The second base 42 may be formed of a divided body that is rotatable about the roll axis. In this case, the link mechanism 6 does not rotate about the roll axis R, but the hand 3 rotates about the roll axis R.

[0104] Regarding the pitch movement, the second base 42 is connected to the link mechanism 6 so as to be rotatable about the pitch axis P. This causes the hand 3 to rotate about the pitch axis P. However, the configuration related to the pitch movement is not limited to this. The first base 41 may be configured of a divided body that is rotatable about the pitch axis. In this case, the link mechanism 6, the second base 42, and the hand 3 rotate about the pitch axis.

[0105] Regarding the yaw movement, the rotor 46 is connected to the base main body 45 of the second base 42 so as to be rotatable about the yaw axis Y. This causes the hand 3 to rotate about the yaw axis Y. However, the configuration related to the yaw movement is not limited to this. The first base 41 may be formed of a divided body that is rotatable about the yaw axis. In this case, the link mechanism 6, the second base 42, and the hand 3 rotate about the yaw axis.

[0106] The technology disclosed herein can be summarized as follows.

[0107] [1] The robot wrist 4 comprises a first base 41 attached to the robot arm 2, a second base 42 to which a hand 3 is attached, a link mechanism 6 movably connecting the second base 42 to the first base 41, and a first actuator 51 driving the link mechanism 6. The link mechanism 6 includes a Chebychev link mechanism 60 connecting the second base 42 to the first base 41 so as to be linearly movably in a predetermined rectilinear direction Z relative to the first base 41. The Chebychev link mechanism 60 has a driver 61 connected to the first base 41 so as to be rotatable around a predetermined drive axis D and driven to rotate, a follower 62 connected to the first base 41 so as to be rotatable around an axis parallel to the drive axis D, and an intermediate link 63 connected to each of the driver 61 and the follower 62 so as to be rotatable around an axis parallel to the drive axis D. The second base 42 is connected to the intermediate link 63.

[0108] According to this configuration, the second base 42 moves relative to the first base 41 via the link mechanism 6, so that the hand 3 moves linearly in the translatory direction Z relative to the robot arm 2. The linear movement by the link mechanism 6 is realized by the Chebychev link mechanism 60. The Chebychev link mechanism 60 has a large stroke of linear movement, but is small in overall size. Therefore, the stroke of the robot wrist 4 in the translatory direction Z can be increased while making the robot wrist 4 compact. Furthermore, the Chebychev link mechanism 60 operates by the rotation of the driving joint 61. That is, the drive source of the Chebychev link mechanism 60 can be driven by a motor. For example, compared to driving by a cylinder or the like, driving by a motor has high controllability. As a result, the position accuracy of the hand 3 in the translatory direction Z is improved.

[0109] [2] The robot wrist 4 described in [1] further includes a second actuator 52 that rotates the second base 42 around a pitch axis P extending in a direction intersecting the linear direction Z, and a pitch transmission mechanism 8 that transmits the driving force of the second actuator 52 to the second base 42.

[0110] According to this configuration, the robot wrist 4 can rotate the hand 3 about the pitch axis P, in addition to linearly moving the hand 3 in the translating direction Z. As a result, the hand 3 can be flexibly moved by the robot wrist 4.

[0111] [3] In the robot wrist 4 described in [1] or [2], the second base 42 is connected to the intermediate link 63 so as to be rotatable around the pitch axis P.

[0112] According to this configuration, during pitch movement of the robot wrist 4, the Chebyshev link mechanism 60 does not rotate about the pitch axis P, but the second base 42 rotates about the pitch axis P relative to the intermediate link 63. This allows the weight of the members that rotate about the pitch axis P to be reduced, improving the controllability of the pitch movement of the robot wrist 4.

[0113] [4] In the robot wrist (4) described in any one of [1] to [3], the pitch transmission mechanism (8) includes a four-bar link mechanism (80).

[0114] According to this configuration, the second base 42 is rotated about the pitch axis P via the four-bar link mechanism 80. Compared to a configuration in which the second base 42 is rotated via a cylinder or the like, the configuration for pitch movement of the robot wrist 4 can be made more compact.

[0115] [5] In the robot wrist (4) described in any one of [1] to [4], the intermediate link (63) functions as a link included in the four-link mechanism (80).

[0116] According to this configuration, since the second base 42 is connected to the intermediate link 63, the intermediate link 63 can be used as a joint of the four-bar link mechanism 80 that rotates the second base 42 about the pitch axis P. By using the intermediate link 63 as a joint of the four-bar link mechanism 80, the four-bar link mechanism 80 can be simplified.

[0117] [6] In the robot wrist 4 described in any one of [1] to [5], the four-bar link mechanism 80 is a parallel link mechanism including a first fixed joint 83 which is the intermediate joint of the Chebyshev link mechanism 60, a first driver 84 connected to the first fixed joint 83 rotatably around an axis parallel to the pitch axis P, a first follower 85 connected to the first fixed joint 83 rotatably around an axis parallel to the pitch axis P and fixed to the second base 42, and a first intermediate joint 86 connected to each of the first driver 84 and the first follower 85 rotatably around an axis parallel to the pitch axis P, and the attitude of the first driver 84 is maintained during operation of the Chebyshev link mechanism 60.

[0118] According to this configuration, the intermediate link 63 of the Chebychev link mechanism 60 also functions as the first fixed link 83 of the four-link mechanism 80. Therefore, when the Chebychev link mechanism 60 operates, the four-link mechanism 80 also operates. Since the four-link mechanism 80 is a parallel link mechanism, the angle of the opposing links remains the same even when the four-link mechanism 80 operates. When the attitude of the first driving link 84 is maintained during the operation of the Chebychev link mechanism 60, the attitude of the first driven link 85 opposing the first driving link 84, that is, the angle of the second base 42, is maintained. As a result, even if the Chebychev link mechanism 60 and the four-link mechanism 80 share some of the links, the hand 3 can be moved in the rectilinear direction Z without changing the pitch angle of the hand 3.

[0119] [7] In the robot wrist 4 described in any one of [1] to [6], the four-bar link mechanism 80 includes a first four-bar link mechanism 81 connected to the second base 42, and a second four-bar link mechanism 82 connected to the first four-bar link mechanism 81 and driven by the second actuator 52.

[0120] According to this configuration, the driving force of the second actuator 52 is transmitted to the second base 42 via the first four-joint link mechanism 81 and the second four-joint link mechanism 82. Since the four-joint link mechanism 80 includes two four-joint link mechanisms, the first four-joint link mechanism 81 and the second four-joint link mechanism 82, a relatively flexible arrangement of the link mechanisms can be realized.

[0121] [8] In the robot wrist 4 described in any one of [1] to [7], the intermediate link 63 functions as a link included in the first four-bar link mechanism 81, and the driven link 62 functions as a link included in the second four-bar link mechanism 82.

[0122] According to this configuration, by using the intermediate link 63 as a link of the first four-bar link mechanism 81 and the driven link 62 as a link of the second four-bar link mechanism 82, the four-bar link mechanism 80 can be simplified.

[0123] [9] In the robot wrist 4 described in any one of [1] to [8], the first four-bar link mechanism 81 includes a first fixed link 83 which is the intermediate link 63 of the Chebyshev link mechanism 60, a first driver 84 connected to the first fixed link 83 so as to be rotatable around an axis parallel to the pitch axis P, a first follower 85 connected to the first fixed link 83 so as to be rotatable around an axis parallel to the pitch axis P, and a first intermediate link 86 connected to each of the first driver 84 and the first follower 85 so as to be rotatable around an axis parallel to the pitch axis P. The second four-bar link mechanism 82 includes a second fixed link 87 which is the follower 62 of the Chebyshev link mechanism 60, and a first intermediate link 86 connected to each of the first driver 84 and the first follower 85 so as to be rotatable around an axis parallel to the pitch axis P. a second driver 88 connected to the second fixed link 87 rotatably about an axis parallel to the pitch axis P, a second follower 89 connected to the second fixed link 87 rotatably about an axis parallel to the pitch axis P, and a second intermediate link 810 connected to each of the second driver and the second follower 84 rotatably about an axis parallel to the pitch axis P, wherein the second driver 88 is rotationally driven by the second actuator 52, the second follower 89 and the first driver 84 are connected by a connecting link 811, and a length of the driver 61 of the Chebyshev link mechanism 60 is longer than or equal to any of the lengths of the first driver 84, the first follower 85, and the second follower 89.

[0124] According to this configuration, the robot wrist 4 can be deformed compactly in the translation direction Z. More specifically, the Chebyshev link mechanism 60 operates by the rotation of the driver 61. The driver 61 is in a state of being most protruding in the translation direction Z when it faces the opposite side to the follower 62 in the translation direction Z, i.e., the backward side. Each of the first driver 84, the first follower 85, and the second follower 89 may also be in a state of being in a state of being in a backward side in the translation direction Z. The length of the driver 61 is longer than or equal to the length of each of the first driver 84, the first follower 85, and the second follower 89. Therefore, even if each of the first driver 84, the first follower 85, and the second follower 89 is in a state of being most protruding in the translation direction Z, it only protrudes to approximately the same extent as the driver 61 in a state of being most protruding in the translation direction Z. In other words, it is possible to prevent any of the first driver 84, the first follower 85, and the second follower 89 from protruding farther in the linear direction Z than the movement range of the driver 61. This makes it possible to prevent the dimension of the robot wrist 4 on the backward side in the linear direction Z from expanding beyond the movement range of the driver 61.

[0125]

[10] In the robot wrist 4 described in any one of [1] to [9], the first four-bar link mechanism 81 includes a first fixed link 83 which is the intermediate link 63 of the Chebyshev link mechanism 60, a first driver 84 which is connected to the first fixed link 83 so as to be rotatable around an axis parallel to the pitch axis P, a first follower 85 which is connected to the first fixed link 83 so as to be rotatable around an axis parallel to the pitch axis P, and a first intermediate link 86 which is connected to each of the first driver 84 and the first follower 85 so as to be rotatable around an axis parallel to the pitch axis P. The second four-bar link mechanism 82 includes a second fixed link which is the follower of the Chebyshev link mechanism 60, The second actuator 52 includes a second driving link 88, a second fixed link 87 rotatably connected to the second fixed link 87 around an axis parallel to the pitch axis P, a second driven link 89 connected to the second fixed link 87 rotatably around an axis parallel to the pitch axis P, and a second intermediate link 810 connected to each of the second driving link 88 and the second driven link 89 around an axis parallel to the pitch axis P, wherein the second driving link 88 is connected to a shaft 812 that is rotationally driven by the second actuator 52, and the second intermediate link 810 is curved to avoid interference with the shaft 812 when it approaches the shaft 812 in conjunction with the second driving link 88.

[0126] According to this configuration, the movement range of the four-joint link mechanism 80 can be expanded, and as a result, the range of pitch movement of the robot wrist 4 can be expanded. In detail, in the first four-joint link mechanism 81 and the second four-joint link mechanism 82, when viewed in the direction of the rotation axis of the second driving link 88, a situation may occur in which any of the links approaches or overlaps any of the joints. For example, the second intermediate link 810 may approach a joint including the rotation axis of the second driving link 88. A shaft 812 is connected to this second driving link 88. The second driving link 88 is rotationally driven by the second actuator 52 via the shaft 812. Therefore, the second intermediate link 810 may approach the shaft 812. The second intermediate link 810 is curved to avoid interference with the shaft 812. In the above example, the second intermediate link 810 has a curved portion 810a that is curved so as to be recessed toward the opposite side to the shaft 812. The curvature of the second intermediate link 810 makes it less likely for the second intermediate link 810 to interfere with the shaft 812. As a result, the motion range of the second intermediate link 810 is expanded, and the range of the pitch motion of the robot wrist 4 is expanded.

[0127]

[11] The robot wrist 4 described in any one of [1] to

[10] further comprises a fourth actuator 54 for rotating the hand 3 around a predetermined yaw axis Y, and a yaw transmission mechanism 79 for transmitting the driving force of the fourth actuator 54, wherein the second base 42 has a rotating body 46 rotatable around the yaw axis Y and to which the hand 3 is attached, and the yaw transmission mechanism 79 transmits the driving force of the fourth actuator 54 to the rotating body 46.

[0128] According to this configuration, the robot wrist 4 can rotate the hand 3 around the yaw axis Y in addition to linearly moving the hand 3 in the rectilinear direction Z. As a result, the robot wrist 4 can flexibly move the hand 3.

[0129]

[12] The robot wrist 4 described in any one of [1] to

[11] further includes a third actuator 53 that rotates the second base 42 around a roll axis R extending in a direction intersecting both the direction of the pitch axis P and the linear direction Z, and the link mechanism 6 is connected to the first base 41 so as to be rotatable around the roll axis R.

[0130] According to this configuration, the robot wrist 4 can rotate the hand 3 about the roll axis R in addition to linearly moving the hand 3 in the translatory direction Z. As a result, the robot wrist 4 can flexibly move the hand 3. Furthermore, in addition to the hand 3, the link mechanism 6 also rotates about the roll axis R. In other words, the orientation of the translatory direction Z rotates about the roll axis R. As a result, the orientation of the direction in which the hand 3 moves linearly can be changed to about the roll axis R.

[0131]

[13] In the robot wrist 4 described in any one of [1] to

[12] , the link mechanism 6 includes a pair of a first link mechanism 6A and a second link mechanism 6B arranged to face each other, each of the first link mechanism 6A and the second link mechanism 6B movably connects the second base 42 to the first base 41 and includes the Chebyshev link mechanism 60, and the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B are connected to each other.

[0132] This configuration improves the support rigidity of the hand 3. More specifically, since the second base 42 is supported by two link mechanisms, the first link mechanism 6A and the second link mechanism 6B, the support rigidity of the second base 42 is improved. Furthermore, the first link mechanism 6A and the second link mechanism 6B face each other, and the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B are connected to each other. This improves the rigidity of the first link mechanism 6A and the second link mechanism 6B. As a result, the support rigidity of the second base 42 is also improved.

[0133]

[14] In the robot wrist (4) according to any one of [1] to

[13] , the first actuator (51) is disposed between the first link mechanism (6A) and the second link mechanism (6B).

[0134] According to this configuration, the first actuator 51 is disposed between the first link mechanism 6A and the second link mechanism 6B, so that the size of the robot wrist 4 in the opposing direction between the first link mechanism 6A and the second link mechanism 6B can be made compact.

[0135]

[15] In the robot wrist 4 described in any one of [1] to

[14] , the driving link 61 of the first link mechanism 6A is positioned inward of the intermediate link 63 of the first link mechanism 6A in the opposing direction between the first link mechanism 6A and the second link mechanism 6B, and the driving link 61 of the second link mechanism 6B is positioned inward of the intermediate link 63 of the second link mechanism 6B in the opposing direction between the first link mechanism 6A and the second link mechanism 6B.

[0136] According to this configuration, the operating range of the two intermediate links 63 can be expanded while arranging the first actuator 51 between the first link mechanism 6A and the second link mechanism 6B. In detail, since the first actuator 51 is arranged between the first link mechanism 6A and the second link mechanism 6B, the first actuator 51 and its transmission mechanism are arranged between the driving link 61 of the first link mechanism 6A and the driving link 61 of the second link mechanism 6B. If the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B are arranged inside the two driving links 61, there is a risk that the two intermediate links 63 will interfere with the first actuator 51 and its transmission mechanism. On the other hand, by arranging the two intermediate links 63 outside the two driving links 61, the two intermediate links 63 can operate without interfering with the first actuator 51 and its transmission mechanism.

[0137]

[16] In the robot wrist 4 described in any one of [1] to

[15] , the joint 64a connecting the driver link 61 and the intermediate link 63 in the first link mechanism 6A and the joint 64a connecting the driver link 61 and the intermediate link 63 in the second link mechanism 6B are connected to each other.

[0138] According to this configuration, by connecting the joint 64a of the first link mechanism 6A and the joint 64a of the second link mechanism 6B, it is possible to simultaneously connect the two driving links 61 and the two intermediate links 63. Furthermore, since the two intermediate links 63 are connected, the rigidity of the intermediate links 63 is improved, and thus the supporting rigidity of the hand 3 by the link mechanism 6 is improved.

[0139]

[17] The robot wrist 4 according to any one of [1] to

[16] further includes a second actuator 52 that rotates the second base 42 around a pitch axis P extending in a direction intersecting the linear direction Z, and a pitch transmission mechanism 8 that transmits the driving force of the second actuator 52 to the second base 42, the second base 42 being connected to the intermediate link 63 so as to be rotatable around the pitch axis P, and the pitch transmission mechanism 8 includes a first four-joint link mechanism 81 connected to the second base 42, and a second four-joint link mechanism 82 connected to the first four-joint link mechanism 81 and driven by the second actuator 52. The intermediate link 63 functions as a first fixed link 83 included in the first four-link link mechanism 81, and the driven link 62 functions as a second fixed link 87 included in the second four-link link mechanism 82, the first four-link link mechanism 81 includes a first intermediate link 86 arranged at a position opposite the first fixed link 83, and the second four-link link mechanism 82 includes a second intermediate link 810 arranged at a position opposite the second fixed link 87, and the first intermediate link 86 and the second intermediate link 810 are arranged in the same plane perpendicular to the opposing direction between the first link mechanism 6A and the second link mechanism 6B.

[0140] According to this configuration, the first intermediate link 86 is included in the first four-bar link mechanism 81, and the second intermediate link 810 is included in the second four-bar link mechanism 82. Therefore, the first intermediate link 86 and the second intermediate link 810 hardly overlap in the facing direction. Even if the first intermediate link 86 and the second intermediate link 810 are arranged in the same plane perpendicular to the facing direction, the first intermediate link 86 and the second intermediate link 810 hardly interfere with each other. By arranging the first intermediate link 86 and the second intermediate link 810 in the same plane, the size of the four-bar link mechanism 80 in the facing direction can be reduced. [Explanation of symbols]

[0141] 4 Robot List 41 First Base 42 Second Base 46 Rotating Body 3 Hands 51 First Actuator 52 Second Actuator 53 Third Actuator 54 4th Actuator 6 Link mechanism 60 Chebyshev link mechanism 61 Motive Clause 62 dependent clause 63 Middle stanza 79 Yaw transmission mechanism 8 Pitch transmission mechanism 80 Four-bar link mechanism 81 First four-section link mechanism 82 2nd four-section link mechanism 83 1st fixed clause 84 First Motive Clause 85 1st dependent clause 86 First Intermediate Node 87 Second fixed clause 88 Second Motive Clause 89 Second dependent clause 810 Second Intermediate Node 811 Connecting Clauses 812 Shaft D Drive shaft Pitch axis R roll axis Y Yaw Axis Z Straight direction

Claims

1. a first base attached to the robot arm; a second base to which the hand is attached; a link mechanism that movably connects the second base to the first base; a first actuator that drives the link mechanism, the link mechanism includes a Chebyshev link mechanism that connects the second base to the first base so as to be linearly movable in a predetermined rectilinear direction, the Chebyshev link mechanism includes a driver connected to the first base rotatably about a predetermined drive shaft and driven to rotate, a follower connected to the first base rotatably about an axis parallel to the drive shaft, and an intermediate link connected to each of the driver and the follower rotatably about an axis parallel to the drive shaft, The second base is a robot wrist connected to the intermediate joint.

2. The robot wrist of claim 1, a second actuator configured to rotate the second base about a pitch axis extending in a direction intersecting the linear direction; and a pitch transmission mechanism that transmits the driving force of the second actuator to the second base.

3. The robot wrist of claim 2, The second base is coupled to the intermediate joint for rotation about the pitch axis.

4. The robot wrist of claim 3, The pitch transmission mechanism is a robot wrist including a four-bar linkage mechanism.

5. The robot wrist of claim 4, The intermediate link is a robot wrist that functions as a link included in the four-link mechanism.

6. The robot wrist of claim 5, The four-bar link mechanism is a parallel link mechanism including: a first fixed joint which is the intermediate joint of the Chebyshev link mechanism; a first driver connected to the first fixed joint rotatably about an axis parallel to the pitch axis; a first follower connected to the first fixed joint rotatably about an axis parallel to the pitch axis and fixed to the second base; and a first intermediate joint connected to each of the first driver and the first follower rotatably about an axis parallel to the pitch axis, A robot wrist wherein the orientation of the first prime mover is maintained during operation of the Chebyshev linkage.

7. The robot wrist of claim 5, The four-bar linkage includes a first four-bar linkage connected to the second base, and a second four-bar linkage connected to the first four-bar linkage and driven by the second actuator.

8. The robot wrist of claim 7, the intermediate link functions as a link included in the first four-link mechanism, The follower link functions as a link included in the second four-link mechanism.

9. The robot wrist of claim 8, the first four-bar link mechanism includes a first fixed joint which is the intermediate joint of the Chebyshev link mechanism, a first driver connected to the first fixed joint rotatably about an axis parallel to the pitch axis, a first follower connected to the first fixed joint rotatably about an axis parallel to the pitch axis, and a first intermediate joint connected to each of the first driver and the first follower rotatably about an axis parallel to the pitch axis, the second four-bar link mechanism includes a second fixed joint which is the follower of the Chebyshev link mechanism, a second driver connected to the second fixed joint rotatably about an axis parallel to the pitch axis, a second follower connected to the second fixed joint rotatably about an axis parallel to the pitch axis, and a second intermediate joint connected to each of the second driver and the second follower rotatably about an axis parallel to the pitch axis, the second driving link is rotationally driven by the second actuator, The second follower node and the first driver node are connected by a connecting node, A robot wrist, wherein a length of the driver of the Chebyshev linkage is greater than or equal to a length of any of the first driver, the first follower, and the second follower.

10. The robot wrist of claim 8, the first four-bar link mechanism includes a first fixed joint which is the intermediate joint of the Chebyshev link mechanism, a first driver connected to the first fixed joint rotatably about an axis parallel to the pitch axis, a first follower connected to the first fixed joint rotatably about an axis parallel to the pitch axis, and a first intermediate joint connected to each of the first driver and the first follower rotatably about an axis parallel to the pitch axis, the second four-bar link mechanism includes a second fixed joint which is the follower of the Chebyshev link mechanism, a second driver connected to the second fixed joint rotatably about an axis parallel to the pitch axis, a second follower connected to the second fixed joint rotatably about an axis parallel to the pitch axis, and a second intermediate joint connected to each of the second driver and the second follower rotatably about an axis parallel to the pitch axis, The second driving link is connected to a shaft that is rotationally driven by the second actuator, The robot wrist has a second intermediate link that is curved to avoid interference with the shaft when the second intermediate link approaches the shaft in conjunction with the second drive link.

11. A robot wrist according to any one of claims 1 to 10, a fourth actuator that rotates the hand around a predetermined yaw axis; a yaw transmission mechanism that transmits a driving force of the fourth actuator, the second base has a rotating body that is rotatable around the yaw axis and to which the hand is attached, The yaw transmission mechanism transmits the driving force of the fourth actuator to the rotating body.

12. A robot wrist according to any one of claims 1 to 10, A third actuator is further provided to rotate the second base about a roll axis extending in a direction intersecting both the pitch axis direction and the linear direction, The link mechanism is a robot wrist rotatably connected to the first base about the roll axis.

13. The robot wrist of claim 1, The link mechanism includes a pair of a first link mechanism and a second link mechanism arranged to face each other, each of the first link mechanism and the second link mechanism movably connects the second base to the first base and includes the Chebyshev link mechanism; A robot wrist in which the intermediate link of the first link mechanism and the intermediate link of the second link mechanism are connected to each other.

14. The robot wrist of claim 13, The first actuator is disposed between the first link mechanism and the second link mechanism.

15. The robot wrist according to claim 13 or 14, the driving link of the first link mechanism is disposed on the inside of the intermediate link of the first link mechanism in a direction in which the first link mechanism and the second link mechanism oppose each other, A robot wrist, wherein the driving link of the second link mechanism is positioned more inward than the intermediate link of the second link mechanism in a direction in which the first link mechanism and the second link mechanism face each other.

16. The robot wrist according to claim 13 or 14, A robot wrist, in which a joint connecting the driver joint and the intermediate joint in the first link mechanism and a joint connecting the driver joint and the intermediate joint in the second link mechanism are connected to each other.

17. The robot wrist according to claim 13 or 14, a second actuator configured to rotate the second base about a pitch axis extending in a direction intersecting the linear direction; a pitch transmission mechanism that transmits a driving force of the second actuator to the second base, the second base is connected to the intermediate joint so as to be rotatable around the pitch axis, the pitch transmission mechanism includes a first four-joint link mechanism connected to the second base, and a second four-joint link mechanism connected to the first four-joint link mechanism and driven by the second actuator, the intermediate link functions as a first fixed link included in the first four-link link mechanism; the driven link functions as a second fixed link included in the second four-link mechanism, the first four-bar link mechanism includes a first intermediate bar arranged at a position opposite to the first fixed bar, the second four-bar link mechanism includes a second intermediate bar arranged at a position opposite to the second fixed bar, A robot wrist in which the first intermediate link and the second intermediate link are arranged in the same plane perpendicular to the opposing direction of the first link mechanism and the second link mechanism.

Images