Robot arm and robot

Abstract

This robot arm comprises: a telescopic arm housing provided with a plurality of housings; an expansion / contraction mechanism that expands and contracts the arm housing in a first direction; at least one operation mechanism; and a guide part. This expansion / contraction mechanism comprises: a first belt housed in the arm housing; a first support part; a belt clamp that fixes the first belt to a distal end housing of the arm housing; and a first drive part. The at least one operation mechanism comprises a second belt housed in the arm housing, a second support part, and a second drive part. The guide part is provided to the arm housing and is configured to guide expansion and contraction of the arm housing. The first belt and the second belt are arranged in a first region in the arm housing, and the guide part is arranged in a second region different from the first region in the arm housing.

Description

Robotic Arms and Robots

[0001] The present disclosure relates to a robotic arm and a robot.

[0002] Robot arms that perform telescopic movements are known. For example, Japanese Patent Publication No. 2016-203289 describes a robot arm with a telescopic structure. This robot arm includes an arm body that can extend and retract in the longitudinal direction, a clip attached to the tip of the arm body, a rotation mechanism that rotates the arm body in the vertical direction, an opening / closing mechanism that opens and closes the clip, an extension / retraction mechanism that extends and retracts the arm body, and servo motors for each mechanism. The servo motors for each mechanism are located at the base end of the arm body.

[0003] In a robot arm that performs extension and retraction operations, depending on the number and structure of devices such as end effectors attached to the tip of the robot arm, in addition to the belt that extends and retracts the arm body, multiple belts for driving devices such as end effectors may be arranged inside the arm body.

[0004] Therefore, there is a demand for improved ease of assembly and maintenance for such robot arms.

[0005] The present disclosure has been made to solve at least part of the above-mentioned problems, and can be realized, for example, in the following aspects.

[0006] According to a first aspect of the present disclosure, there is provided a robot arm. The robot arm includes a telescopic arm housing, an extension / retraction mechanism, at least one movement mechanism, and a guide unit. The arm housing extends in a first direction. The arm housing includes a plurality of housings, including a distal housing and a proximal housing capable of accommodating the distal housing. The extension / retraction mechanism is configured to extend and retract the arm housing in the first direction. The extension / retraction mechanism includes a first belt accommodated in the arm housing, a first support unit, a belt clamp, and a first drive unit. The first support unit includes a first shaft extending in a second direction perpendicular to the first direction. The first support unit is configured to rotatably support the first belt on the arm housing. The belt clamp secures the first belt to the distal housing. The first drive unit is configured to drive the first belt. The at least one movement mechanism is configured to transmit power to an end effector attached to a free end of the distal housing. The at least one operating mechanism includes a second belt housed in the arm housing, a second support unit, and a second drive unit. The second support unit includes a second shaft extending in the second direction. The second support unit is configured to rotatably support the second belt on the arm housing. The second drive unit is configured to rotate the second belt. The guide unit is provided on the arm housing. The guide unit is configured to guide extension and contraction of the arm housing in the first direction. The first belt and the second belt are arranged in a first region within the arm housing in the second direction. The guide unit is arranged in a second region within the arm housing that is different from the first region in the second direction.

[0007] According to a second aspect of the present disclosure, there is provided a robot including the robot arm.

[0008] FIG. 1 is a schematic diagram showing a robot system including a robot. FIG. 2 is a schematic diagram showing an example of a pick-and-place operation. FIG. 3 is a perspective view of a robot arm in a contracted state. FIG. 4 is a perspective view of a robot arm in an extended state. FIG. 5 is a side view of the robot arm in a contracted state. FIG. 6 is a side view of the robot arm in an extended state. FIG. 7 is a top view of the robot arm in an extended state. FIG. 8 is a perspective view of the robot arm in a contracted state with the top wall of the arm housing removed, and is a diagram for explaining the cable housing. FIG. 9 is a perspective view of the robot arm in an extended state with the top wall of the arm housing removed, and is a diagram for explaining the cable housing. FIG. 10 is a cross-sectional view taken along the line X-X in FIG. 5. FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. 7, and is a diagram for explaining a guide portion. FIG. 12 is a perspective view of the robot arm with part of the arm housing removed. FIG. 13 is a perspective view of the robot arm with the arm housing removed, and is a diagram for explaining the extension / retraction mechanism and the operation mechanism. FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. 5, showing the inside of the arm housing when the robot arm is in a contracted state. FIG. 15 is a cross-sectional view of the robot arm in an extended state corresponding to FIG. 14. FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 7, showing the adjustment unit. FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. 16, showing the adjustment unit. FIG. 18 is a perspective view of a portion of the multiple shaft cut away. FIG. 19 is a cross-sectional view of the multiple shaft and robot wrist, including the pivot axis and perpendicular to the Y axis. FIG. 20 is an explanatory diagram showing the drive unit. FIG. 21 is a perspective view of the robot arm and the robot wrist attached to the robot arm. FIG. 22 is a perspective view of the robot wrist in the highest position. FIG. 23 is a side view of the robot wrist in the highest position. FIG. 24 is a front view of the robot wrist in the highest position. FIG. 25 is a top view of the robot wrist in the highest position. FIG. 26 is a bottom view of the robot wrist in the highest position. Figure 27 is a perspective view of the robot wrist in the lowest position, Figure 28 is a side view of the robot wrist in the lowest position, and Figure 29 is a perspective view of the robot wrist in the highest position, illustrating the interior of the wrist housing.FIG. 30 is another perspective view of the robot wrist in the fully raised state and is a diagram for explaining the interior of the wrist housing. FIG. 31 is a cross-sectional view taken along the line XXXI-XXXI in FIG. 25. FIG. 32 is a cross-sectional view taken along the line XXXII-XXXII in FIG. 25. FIG. 33 is a left side view of the robot wrist in the fully raised state, excluding the left portion of the wrist housing, and is a diagram for explaining the operation of the link mechanism. FIG. 34 is a left side view of the robot wrist in the fully lowered state, excluding the left portion of the wrist housing, and is a diagram for explaining the operation of the link mechanism. FIG. 35 is a cross-sectional view taken along the line XXXV-XXXV in FIG. 24. FIG. 36 is a cross-sectional view taken along the line XXXVI-XXXVI in FIG. 25. FIG. 37 corresponds to FIG. 36 and shows the mounting portion rotated by the pitch movement portion. FIG. 38 is a diagram showing a drive portion of a comparative example. FIG. 39 is a table showing each operation of the robot arm and robot wrist and the rotation direction and rotation amount of each belt required to perform each operation independently. FIG. 40 is a diagram showing a structure of a reference example having two movable parts in a driven relationship. FIG. 41 is a diagram illustrating how a second movable part is driven by a first movable part using the XLI-XLI cross-sectional view of FIG. 40 , showing the structure in an initial state. FIG. 42 is a diagram illustrating how the second housing rotates relative to the first housing as the first housing rotates from the initial state shown in FIG. 40 . FIG. 43 is a diagram illustrating how only the first housing rotates while maintaining the positional relationship between the first and second housings in the initial state by rotating the rotating body and the shaft. FIG. 44 is a schematic diagram showing a structure to which a control mechanism is applied. FIG. 45 is a schematic vertical cross-sectional view of a differential gear. FIG. 46 is a diagram illustrating the rotation of the balls and the movement amount of the shafts when the rotating body of the differential gear is fixed. FIG. 47 is a diagram illustrating the rotation of one shaft and the other shaft when the rotating body is fixed. FIG. 48 is a diagram illustrating the rotation of the balls and the movement amount of the other shaft when one shaft of the differential gear is fixed. Fig. 49 is a diagram for explaining the rotation of the rotor and one shaft when the other shaft is fixed. Fig. 50 is a cross-sectional view taken along line LL in Fig. 44.Figure 51 is a diagram illustrating how the driven relationship between the first movable part and the second movable part is canceled by the control mechanism. Figure 52 is a diagram illustrating a speed reducer and a differential gear in the drive part. Figure 53 is a diagram illustrating a power transmission path in an arm extension operation. Figure 54 is a diagram illustrating a power transmission path in a wrist rotation operation. Figure 55 is a diagram illustrating a power transmission path in a wrist lift operation. Figure 56 is a diagram illustrating a power transmission path in a wrist pitch operation.

[0009] <Robot System> Fig. 1 is a schematic diagram showing a robot system 100 including a robot 1 according to an embodiment of the present disclosure. The robot system 100 includes the robot 1 and a control device 101 that controls the robot 1. The robot 1 performs, for example, a pick-and-place operation in which a workpiece W placed at a transfer source is transported to a transfer destination. In Fig. 1, the robot 1 picks up a workpiece W from a first container C1 placed on a shelf S and transports it to a second container C2.

[0010] 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 work space H is present between the first container C1 and the shelf board s1 located above the first container C1, and the work space H allows the robot arm 4 of the robot 1 to enter.

[0011] The robot 1 includes a robot arm 4 that extends and retracts in a predetermined first direction, a robot wrist 7 connected to the robot arm 4, a hand 190 connected to the robot wrist 7, and a drive unit 2. The robot wrist 7 moves the hand 190 in a predetermined second direction. The robot wrist 7 also rotates the hand 190 around a predetermined axis. The control device 101 uses the robot arm 4 and the robot wrist 7 to move the hand 190.

[0012] The robot 1 further includes a carriage 11 and a lifting device 12 that is disposed on the carriage 11 and supports the robot arm 4 so that the robot arm 4 can be raised and lowered. The carriage 11 is, for example, an AGV (Automated Guided Vehicle). The robot 1 moves by the movement of the carriage 11. The carriage 11 includes a box-shaped main body 110. The main body 110 has an upper surface 111 and a recess 112 that is recessed downward from the upper surface 111. The upper surface 111 also functions as a mounting surface for a container or the like. In the example shown in FIG. 1 , a second container C2 is loaded on the upper surface 111.

[0013] The lifting device 12 raises, lowers, and rotates the robot arm 4. The lifting device 12 has a support column 120 extending in the vertical direction. The central axis of the support column 120 is also referred to as the lifting axis U. The support column 120 is attached to the cart 11 so as to be rotatable around the lifting axis U. In the example shown in FIG. 1 , the support column 120 is attached to a recess 112 of the cart 11. The lifting device 12 includes a rotation actuator configured to rotate the support column 120 around the lifting axis U, and a lifting actuator configured to move the robot arm 4 along the lifting axis U. The lifting device 12 rotates the support column 120 around the lifting axis U using the rotation actuator, thereby rotating the robot arm 4 around the lifting axis U. The lifting device 12 moves the robot arm 4 along the lifting axis U using the lifting actuator.

[0014] The robot arm 4 is a linear-acting telescopic arm. The robot arm 4 extends and retracts in the direction of a predetermined advance / retract axis V. The direction of the advance / retract axis V is also the first direction. The advance / retract axis V and the lifting axis U are perpendicular to each other. In this embodiment, the robot arm 4 is attached to the lifting device 12 so that the advance / retract axis V is perpendicular to the lifting axis U. The robot arm 4 includes a telescopic arm housing 40 that extends in the direction of the advance / retract axis V. The arm housing 40 includes a plurality of cylindrical housings. The robot arm 4 extends and retracts in the first direction as the multiple cylindrical housings move relatively in the direction of the advance / retract axis V. The robot arm 4 is also simply referred to as an "arm."

[0015] The robot wrist 7 is rotatably attached to the tip of the robot arm 4. A rotation axis T (see FIG. 2) of the robot wrist 7 extends in a second direction perpendicular to the first direction. An attachment portion 191 to which a hand 190 is detachably attached is provided at the tip of the robot wrist 7. The robot wrist 7 moves the hand 190 in the second direction by moving the attachment portion 191 in the second direction. The robot wrist 7 has a pitch axis P extending in a predetermined direction at the attachment portion 191. In the example shown in FIG. 1, the pitch axis P is perpendicular to the first direction and the second direction. The robot wrist 7 rotates the hand 190 around the pitch axis P. The rotational movement around the pitch axis P is also called a "wrist pitch movement."

[0016] In FIG. 1 and the following figures, the X-axis and Z-axis directions are shown as appropriate. The X-axis direction is the direction of the forward / backward axis V, i.e., the first direction. The +X-axis direction is the direction in which the robot arm 4 extends, and the −X-axis direction is the direction in which the robot arm 4 retracts. The +X-axis direction is also referred to as the forward direction, and the −X-axis direction is also referred to as the backward direction. The Z-axis direction corresponds to the second direction. The Z-axis direction is perpendicular to the X-axis direction. In this embodiment, the Z-axis direction is the up-down direction. The +Z-axis direction is the upward direction, and the −Z-axis direction is the downward direction. In FIG. 3 and the following figures, the Y-axis direction is shown as appropriate. The Y-axis direction is perpendicular to the X-axis and Z-axis directions. Note that in this embodiment, the second direction (Z-axis direction) in which the robot wrist 7 moves the hand 190 is the same as the extension direction of the lifting / lowering axis U of the lifting device 12, but the second direction may be different from the extension direction of the lifting / lowering axis U.

[0017] The hand 190 is detachably attached to a mounting portion 191 of the robot wrist 7. The hand 190 holds the workpiece W. The hand 190 is equipped with a known actuator and motor for holding the workpiece W. In this embodiment, the hand 190 is configured to hold the workpiece W by suction. The manner in which the hand 190 holds the workpiece W is not limited to suction, and may also be, for example, gripping.

[0018] The drive unit 2 is configured to output power to the robot arm 4 and the robot wrist 7 connected to the robot arm 4. As shown in FIG. 1, the drive unit 2 is located at the base end 404, which is the end of the robot arm 4 in the -X axis direction, and is attached to the lifting device 12 integrally with the robot arm 4. The drive unit 2 includes motors whose number corresponds to the degrees of freedom of the robot arm 4 and the robot wrist 7. In this embodiment, the drive unit 2 includes four motors M, M1, M2, and M3 (see FIG. 20). In this embodiment, the motors M, M1, M2, and M3 are servo motors with servo lock functions.

[0019] The drive unit 2 further includes a control mechanism 20. The control mechanism 20 is configured to independently operate multiple movable parts that are in a mutually driven relationship. The term "driven relationship" refers to a relationship in which, in a structure having multiple movable parts including a first movable part and at least one second movable part, when the first movable part is operated, at least one second movable part is operated as a result of the operation of the first movable part. The robot arm 4, robot wrist 7, and control mechanism 20 will be described in detail below.

[0020] The robot 1 further includes an imaging device 15. The imaging device 15 may include a camera having an optical system and a two-dimensional imaging element. In the example shown in Fig. 1, the imaging device 15 is provided in the hand 190. Instead of or in addition to the hand 190, the imaging device 15 may be attached to a wall or ceiling around the robot 1, or may be attached to the robot arm 4 or the robot wrist 7. The imaging device 15 acquires images of the inside of the first container C1 and the second container C2.

[0021] The control device 101 includes a processor such as a CPU that performs various arithmetic operations, and a storage device. The storage device includes, for example, a nonvolatile memory and a volatile memory. The CPU controls the robot 1 by expanding and executing various programs stored in the memory. The control device 101 outputs commands to the robot control device 10 included in the robot system 100, for example, to move the robot arm 4 along the lifting axis U, rotate the robot arm 4, and extend and retract the robot arm 4. The robot control device 10 includes a processor such as a CPU that performs various arithmetic operations, and a storage device. The storage device includes, for example, a nonvolatile memory and a volatile memory. The CPU of the robot control device 10 expands and executes various programs stored in the memory, thereby controlling the actuators of the lifting device 12 and the motors M, M1, M2, and M3 in response to commands from the control device 101.

[0022] A pick-and-place operation of a workpiece W by the robot 1 will be briefly described using FIG. 2 . When the control device 101 outputs a command to the robot control device 10, the robot 1 moves the cart 11 to a position facing the shelf S. The lifting device 12 moves the robot arm 4 so that the hand 190 is positioned facing the workspace H between the target first container C1 and the shelf s1 located above it. Next, the robot 1 extends the robot arm 4 to cause the robot arm 4 to enter the workspace H. This causes the robot wrist 7 and the hand 190 to enter the workspace H. Furthermore, the robot 1 moves the hand 190 via the robot wrist 7 to above the workpiece W to be grasped. In the example shown in FIG. 2 , the robot 1 rotates the hand 190 around the pitch axis P via the robot wrist 7. Furthermore, the robot 1 moves the hand 190 in the −Z-axis direction via the robot wrist 7 to bring the hand 190 into contact with the workpiece W and grasp (suck) the workpiece W.

[0023] After gripping the workpiece W, the robot 1 moves the hand 190 from inside the first container C1 to the workspace H via the robot wrist 7. Next, the robot 1 retracts the robot arm 4, and causes the workpiece W gripped by the hand 190, the hand 190, the robot wrist 7, and the robot arm 4 to exit the workspace H. The robot 1 rotates and raises and lowers the lifting device 12 to move the hand 190 to an upper position inside 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 hand 190. In this manner, the workpiece W to be gripped is moved from the first container C1 to the second container C2.

[0024] <Robot Arm> The robot arm 4 will be described in detail below with reference to Figs. 3 to 20. Fig. 3 is a perspective view of the robot arm 4 in a contracted state. Fig. 4 is a perspective view of the robot arm 4 in an extended state. The robot arm 4 has a telescopic structure. Fig. 3 shows the robot arm 4 in its most contracted state, and Fig. 4 shows the robot arm 4 in its most extended state. Hereinafter, the most extended state of the robot arm 4 will also be referred to as the "longest state," and the most contracted state of the robot arm 4 will also be referred to as the "shortest state." The length of the robot arm 4 along the X-axis direction changes between the longest state and the shortest state.

[0025] The robot arm 4 mainly comprises an arm housing 40, an extension / retraction mechanism 47 (see FIGS. 10 and 13), an operating mechanism 50 (see FIG. 12), and a guide unit 45 (see FIG. 11). The extension / retraction mechanism 47 extends and retracts the robot arm 4 in the X-axis direction. The operating mechanism 50 operates the end effector by transmitting power to the end effector via the robot arm 4. The guide unit 45 guides the extension and retraction of the arm housing 40 in the X-axis direction.

[0026] The end effector is provided on the free end 405 side of the robot arm 4. In this embodiment, the end effector is the robot wrist 7 and the hand 190. The robot wrist 7 is connected to the free end 405 of the robot arm 4 and is rotatable around a rotation axis T. The robot wrist 7 raises and lowers the hand 190 via the mounting portion 191. The robot wrist 7 also rotates the hand 190 around a pitch axis P via the mounting portion 191. In other words, the robot arm 4 transmits power corresponding to three degrees of freedom (rotation of the robot wrist 7, raising and lowering of the mounting portion 191, and rotation of the mounting portion 191). Therefore, the robot arm 4 is provided with an operating mechanism 50 corresponding to each degree of freedom. Specifically, the operating mechanism 50 includes a first mechanism 51 that transmits power for rotating the robot wrist 7, a second mechanism 52 that transmits power for raising and lowering the hand 190 via the mounting portion 191, and a third mechanism 53 that transmits power for pitching the hand 190 via the mounting portion 191. The extension / retraction mechanism 47 and the operating mechanism 50 will be described in detail below.

[0027] <Arm Housing> The outer casing of the robot arm 4 is defined by the arm housing 40. As shown in FIGS. 3 to 7 , the arm housing 40 includes multiple housings extending in a first direction (X-axis direction). In this embodiment, the arm housing 40 includes a base housing 43, an intermediate housing 42, and a tip housing 41. As shown in FIG. 7 , the central axis AX of each of the housings 43, 42, and 41 extends in the X-axis direction. The tip housing 41 is housed in the intermediate housing 42 so as to be able to move forward and backward in the X-axis direction. The intermediate housing 42 is housed in the base housing 43 so as to be able to move forward and backward in the X-axis direction. The end of the arm housing 40 (robot arm 4) in the +X-axis direction is configured as a free end 405. The free end 405 is also the end of the tip housing 41 in the +X-axis direction. Hereinafter, the end of the tip housing 41 in the -X-axis direction will also be referred to as the rear end 41b. The end of the intermediate housing 42 in the +X-axis direction is also referred to as a front end 42f, the end in the -X-axis direction as a rear end 42b, and the end of the base housing 43 in the +X-axis direction as a front end 43f.

[0028] In this embodiment, the width direction of the arm housing 40 is the Y-axis direction. The lengths (widths) of the base end housing 43, the intermediate housing 42, and the tip housing 41 in the Y-axis direction decrease in this order. For ease of explanation, hereinafter, the right direction when looking at the robot arm 4 in the +X-axis direction from the base end 404 will also be referred to as the +Y-axis direction, and the opposite direction will also be referred to as the −Y-axis direction.

[0029] 8 and 9 show perspective views of the robot arm 4, excluding the upper walls 401, 402, and 403 (see FIGS. 4 and 7) in the +Z-axis direction of the arm housing 40. Also, Fig. 10 shows a cross-sectional view of the robot arm 4 perpendicular to the X-axis direction, which is the X-X cross-sectional view of Fig. 5. Fig. 10 shows an imaginary plane AP that includes the central axis AX and is perpendicular to the Y-axis direction.

[0030] 9 and 10, the tip housing 41 includes an extending portion 411 extending in the X-axis direction and a pair of protruding portions 412 provided on the rear end portion 41b. As shown in Fig. 10, the pair of protruding portions 412 are connected to the extending portion 411 and protrude in a direction away from the imaginary plane AP.

[0031] The intermediate housing 42 includes an extending portion 421 extending in the X-axis direction, a pair of protruding portions 422 provided at the rear end portion 42b, and a pair of protruding portions 423 provided at the front end portion 42f. As shown in Fig. 10, the pair of protruding portions 422 are connected to the extending portion 421 and protrude in a direction away from the imaginary plane AP. The pair of protruding portions 423 are connected to the extending portion 421 and protrude in a direction toward the imaginary plane AP.

[0032] The base end housing 43 includes an extending portion 431 and a pair of protruding portions 433 provided on the front end portion 43f. The protruding portions 433 are connected to the extending portion 431 and protrude in a direction approaching the imaginary plane AP.

[0033] As shown in Figures 8 and 9, the protrusion 412 of the tip housing 41 is disposed rearward of the protrusion 423 of the intermediate housing 42. The protrusions 412 and 423 face each other in the X-axis direction. Therefore, when the tip housing 41 moves in the +X-axis direction relative to the intermediate housing 42, the protrusions 412 and 423 interfere with each other, preventing the tip housing 41 from coming off the intermediate housing 42. Furthermore, the protrusion 422 of the intermediate housing 42 is disposed rearward of the protrusion 433 of the base housing 43. The protrusions 422 and 433 face each other in the X-axis direction. Therefore, when the intermediate housing 42 moves in the +X-axis direction relative to the base housing 43, the protrusions 422 and 433 interfere with each other, preventing the tip housing 41 from coming off the intermediate housing 42.

[0034] 8 and 9, the robot arm 4 further includes a cable housing 44 extending in the X-axis direction. As shown in Fig. 10, the cable housing 44 is disposed in an upper portion within the arm housing 40. The cable housing 44 has a telescopic structure, similar to the arm housing 40.

[0035] As shown in FIG. 9 , the cable housing 44 includes a tip accommodating portion 441 supported by the tip housing 41, an intermediate accommodating portion 442 supported by the intermediate housing 42, and a base accommodating portion 443 supported by the base housing 43. As shown in FIG. 10 , the tip accommodating portion 441, the intermediate accommodating portion 442, and the base accommodating portion 443 are covered in the +Z-axis direction by upper walls 401, 402, and 403, thereby defining an accommodating space extending in the X-axis direction. As shown in FIG. 9 , a tip end 441s (the end in the +X-axis direction) of the tip accommodating portion 441 communicates with an internal space 60 of the multiple shaft 6, the details of which will be described later. A rear end 443s of the base accommodating portion 443 communicates with the outside of the arm housing 40.

[0036] The cable housing 44 can accommodate cables connected to the hand 190 or sensors such as the imaging device 15 provided on the hand 190. This prevents the cables from becoming entangled with the belts 471, E1, E2, and E3 when the robot arm 4 extends or retracts. This also makes it easy to arrange the cables on the robot arm 4, which facilitates assembly of the robot arm 4.

[0037] <Guide Section> The guide section 45 will be described using Figures 10 and 11. The guide section 45 is configured to guide the extension and contraction (movement) of the arm housing 40 in the X-axis direction. In this embodiment, the guide section 45 is configured by rails 454, 455 extending in the X-axis direction and block-shaped carriages 451, 452 that slide on the rails 454, 455. Grooves 451g, 452g that extend in the X-axis direction and fit into the rails 454, 455 are formed in the lower parts of the carriages 451, 452.

[0038] The carriage 451 is provided at the lower end of the protruding portion 412 of the tip housing 41. The rail 454 is provided at a position corresponding to the range of movement of the protruding portion 412 in the +Y-axis direction and the −Y-axis direction of the extending portion 421 of the intermediate housing 42. As the extension mechanism 47 extends or retracts the arm housing 40, the carriage 451 slides on the rail 454, and the tip housing 41 is guided in the X-axis direction relative to the intermediate housing 42.

[0039] The carriage 452 is provided at the lower end of the protruding portion 422 of the intermediate housing 42. The rail 455 is provided at a position corresponding to the range of movement of the protruding portion 422 in the +Y-axis direction and the −Y-axis direction of the extending portion 431 of the base housing 43. As the extension / contraction mechanism 47 extends or contracts the arm housing 40, the carriage 452 slides on the rail 455, thereby guiding the intermediate housing 42 in the X-axis direction relative to the base housing 43. In this way, the guide portion 45 guides the extension and contraction of the arm housing 40 in the X-axis direction.

[0040] <Telescoping Mechanism and Operation Mechanism> Next, the telescoping mechanism 47 and operation mechanism 50 will be described mainly using Figures 10, 12, and 13. The telescoping mechanism 47 includes a belt 471 for extending and retracting the arm. As described above, the operation mechanism 50 includes the first mechanism 51, the second mechanism 52, and the third mechanism 53. Each of the mechanisms 51, 52, and 53 includes belts E1, E2, and E3. Therefore, four belts are arranged inside the arm housing 40. Belt E1 transmits power for rotating the robot wrist 7. Belt E2 transmits power for raising and lowering the robot wrist 7. Belt E3 transmits power for pitching the robot wrist 7.

[0041] As shown in FIG. 10 , the arm extension / retraction belt 471 and the end effector belts E1, E2, and E3 are disposed within the arm housing 40 so as not to overlap with the guide portion 45 in the Z-axis direction. FIG. 10 shows a first region Ar1 in which the belts 471, E1, E2, and E3 are disposed, and a second region Ar2 in which the guide portion 45 is disposed. In this embodiment, the second region Ar2 is provided at the lower end of the arm housing 40, and the first region Ar1 is provided above the second region Ar2. FIG. 10 also shows a third region Ar3 in which the cable housing 44 is disposed. The third region Ar3 is provided above the first region Ar1. Thus, in this embodiment, the belts 471, E1, E2, and E3 and the guide portion 45 are disposed in different regions in the Z-axis direction. This reduces interference between the belts 471, E1, E2, and E3 and the guide portion 45. Furthermore, assembly of the robot arm 4 is facilitated. Furthermore, the cable housing 44 is provided in a different area (third area Ar3) in the Z-axis direction from the first area Ar1 and the second area Ar2, which reduces interference between the cable housing 44, the belts 471, E1, E2, and E3, and the guide portion 45. This also makes it easier to assemble the robot arm 4.

[0042] <Extendable Mechanism> The extendable mechanism 47 will be described in detail. The extendable mechanism 47 includes a belt 471 for extending and retracting the arm, a support unit 48, a belt clamp 472 (see FIGS. 13 to 15), and a drive unit 473 (see FIG. 20). The extendable mechanism 47 is generally disposed in the left portion of the arm housing 40 (in the −Y-axis direction with respect to the imaginary plane AP). As shown in FIG. 10, the belt 471 is disposed in the upper left portion of the first region Ar1.

[0043] The support portion 48 rotatably supports a belt 471 for extending and retracting the arm on the arm housing 40. As shown in Figures 12 and 13, the support portion 48 includes shafts 481f, 481b, 481c, 482f, 482b, 482c, 483f, 202, and 21 extending in the Z-axis direction.

[0044] 12, the shafts 481f, 481b, and 481c are provided in the tip housing 41. The shaft 481f is fixed to the free end 405 of the tip housing 41. The shaft 481b is fixed to a protrusion 412 provided at the rear end of the tip housing 41. The shaft 481c is fixed to the protrusion 412, further forward than the shaft 481b.

[0045] The shafts 482f, 482b, and 482c are provided in the intermediate housing 42. The shaft 482f is fixed to a protrusion 423 provided at the front end of the intermediate housing 42. The shafts 482b and 482c are fixed to a protrusion 422 provided at the rear end of the intermediate housing 42. The shaft 482c is fixed to the protrusion 422 on a position forward of the shaft 482f.

[0046] The shafts 483f, 202, and 21 are provided in the base housing 43. The shaft 483f is fixed to a protrusion 433 provided at the front end of the base housing 43. The shafts 202 and 21 are arranged side by side in the Y-axis direction at the base end 404 of the base housing 43. The shafts 202 and 21 are rotatably supported by the base housing 43.

[0047] Rotating bodies 485 are provided on the shafts 481f, 481b, and 481c provided in the distal housing 41, the shafts 482f, 482b, and 482c provided in the intermediate housing 42, and the shaft 483f provided in the proximal housing 43, respectively, and are rotatable relative to each shaft. For clarity of illustration, the reference numerals of the rotating bodies 485 rotatably provided on each shaft have been omitted as appropriate. This also applies to the rotating body 515 in the operating mechanism 50. In this embodiment, the protruding portions 412, 422, 423, and 433 are provided with recesses in which the rotating bodies 485 can be disposed. As shown in FIG. 20 , the shafts 202 and 21 are provided with multiple rotating bodies. The support portion 48 includes a rotating body 305, which is one of the multiple rotating bodies provided on the shaft 202 and rotates integrally with the shaft 202, and a rotating body 314, which is one of the multiple rotating bodies provided on the shaft 21 and is rotatable relative to the shaft 21. 20 and the following figures, the hatching on each rotating body is intended to distinguish the type of rotating body and does not represent the number of teeth on the rotating body (pulley). The multiple rotating bodies and each shaft in the drive unit 2 will be described later.

[0048] A motor M for extending and retracting the arm is operably connected to the shaft 202. The motor M is provided at the base end 404. The motor M is included in the drive unit 473. The shaft 202 is also a drive shaft that is operably connected to the motor M and outputs the power of the motor M. Therefore, the shaft 202 can also be considered as part of the drive unit 473. The base end 404 is further provided with motors M1, M2, and M3 that correspond to belts E1, E2, and E3 for the end effectors.

[0049] 12, 13, and 20, belt 471 is stretched over rotating body 305 that rotates integrally with shaft 202, rotating body 314 rotatably provided on shaft 21, and rotating bodies 485 rotatably provided on each of shafts 481f, 481b, 481c, 482f, 482b, 482c, and 483f, and is rotatably supported by arm housing 40. In other words, belt 471 is supported at base end 404, free end 405, rear end 41b of tip housing 41, front end 42f of intermediate housing 42, rear end 42b of intermediate housing 42, and front end 43f of base housing 43.

[0050] In this embodiment, the belts 471, E1, E2, and E3 are timing belts. Of the rotating bodies 305, 314, and 485, the rotating bodies that contact the belt teeth are toothed pulleys. The rotating bodies that do not contact the belt teeth may be rollers. The same applies to the operating mechanism 50.

[0051] 14 and 15 , the belt clamp 472 secures the belt 471 to the tip housing 41. In this embodiment, the belt clamp 472 is secured to the extension portion 411 at the rear end portion 41b of the tip housing 41.

[0052] The extension and retraction operation of the arm housing 40 will be described using Figures 14 and 15. Figure 14 shows the axis AX202 of the shaft 202 and the rotation directions r1 and r2 of the shaft 202. The rotation direction r2 is opposite to the rotation direction r1. In this embodiment, the rotation direction r1 is counterclockwise, and the rotation direction r2 is clockwise. The axis AX202 of the shaft 202 is parallel to the axes AX21, AX22, and AX23 of the shafts 21, 22, and 23.

[0053] When the motor M rotates the shaft 202 in the rotational direction r1, the belt 471 rotates in the direction of arrow R1 due to the rotation of the shaft 202. As described above, the belt clamp 472 is fixed to the tip housing 41. Therefore, for example, when the belt 471 rotates in the direction of arrow R1 in the contracted state shown in FIG. 14 , the belt 471, which is arranged from the belt clamp 472 through the intermediate housing 42 to the base housing 43, is gradually fed in the direction of arrow R1 along the direction of arrow R1. This pushes the free end 405 in the +X-axis direction. In other words, the tip housing 41 moves in the +X-axis direction, the intermediate housing 42 moves in the +X-axis direction, and the entire arm housing 40 extends in the +X-axis direction. As a result, the arm housing 40 transitions from the contracted state shown in FIG. 14 to the extended state shown in FIG. 15 .

[0054] Furthermore, when the motor M rotates the shaft 202 in the rotational direction r2 from the extended state shown in FIG. 15 , the belt 471 is driven to rotate in the direction of arrow R2. Because the belt clamp 472 is fixed to the tip housing 41, when the belt 471 rotates in the direction of arrow R2, the belt 471, which is disposed from the free end 405 to the base end 404 in the direction along arrow R2, is gradually fed in the direction of arrow R2. This causes the free end 405 to move in the −X-axis direction. That is, the tip housing 41 moves in the −X-axis direction, and the middle housing 42 moves in the −X-axis direction. As a result, the tip housing 41 is housed in the middle housing 42, and the middle housing 42 is housed in the base housing 43. That is, the arm housing 40 contracts. As a result, the arm housing 40 transitions from the extended state shown in FIG. 15 to the contracted state shown in FIG. 14 .

[0055] <Operation Mechanism> Next, the operation mechanism 50 will be specifically described mainly with reference to Figures 10 to 15 and 20. As shown in Figure 12, the first mechanism 51 included in the operation mechanism 50 includes a belt E1 that transmits power for turning the robot wrist 7, a support unit 510, and a drive unit 516 (see Figure 20). The support unit 510 is configured to support the belt E1 on the arm housing 40 in the -Z axis direction of the belt 471.

[0056] As shown in FIGS. 12 and 13 , the support unit 510 includes multiple shafts and rotating bodies provided on each shaft. The multiple shafts include shafts 481f, 481b, and 481c provided on the distal housing 41, shafts 511, 482b, and 482c provided on the intermediate housing 42, and shafts 512, 202, and 21 provided on the proximal housing 43. As shown in FIG. 12 , of the multiple shafts in the support unit 510, the shaft 511 provided on the front end 42f (protruding portion 423) of the intermediate housing 42 is formed separately from the shaft 482f in the support unit 48 described above. The shaft 512 provided on the front end 43f (protruding portion 433) of the proximal housing 43 is also formed separately from the shaft 483f in the support unit 48 described above. The other shafts provided in the support unit 510 are also used as the shafts provided in the support unit 48.

[0057] Rotating bodies 515 are provided on the shafts 481f, 481b, and 481c provided on the tip housing 41, the shafts 511, 482b, and 482c provided on the intermediate housing 42, and the shaft 512 provided on the base housing 43. Note that in Fig. 12, only the rotating body 515 provided on the shaft 481f is indicated by a reference numeral. Each rotating body 515 is rotatable relative to the corresponding shaft.

[0058] As shown in FIG. 20 , the support portion 510 further includes a rotor 307 that is rotatable relative to the shaft 202, and a rotor 312 that is provided on the shaft 21 and rotates as the shaft 21 rotates. The rotor 312 is a pulley incorporated into a ball differential (ball differential device). A pulley incorporated into a ball differential will also be referred to as a retainer pulley hereinafter. Note that the rotors 321, 323, and 331 described below are also retainer pulleys. The rotors 312, 321, 323, and 331 are each elements of a differential device. The differential device will be described in detail below.

[0059] A motor M1 for rotating the wrist is operably connected to the shaft 21. The motor M1 is provided at the base end 404. The motor M1 is included in the drive unit 516. The shaft 21 is also a drive shaft that is operably connected to the motor M1 and outputs the power of the motor M1. Therefore, the shaft 21 can also be considered as part of the drive unit 516.

[0060] With the above configuration, belt E1 is stretched over rotating body 307 rotatably supported on shaft 202, rotating body 312 which rotates due to the rotation of shaft 21, and rotating body 515 which is rotatably provided on each of shafts 481f, 481b, 481c, 511, 482b, 482c, and 512, and is rotatably supported on arm housing 40.

[0061] 12 and 13 , the first mechanism 51 further includes a belt E11 disposed at the free end 405. The belt E11 is stretched between a rotating body 515 provided on the shaft 481f and a rotating body provided on the multiple shaft 6 provided at the free end 405.

[0062] When the wrist rotation motor M1 rotates the shaft 21 in a rotation direction r3 shown in Figure 14, the belt E1 rotates in the direction of arrow R3. When the motor M1 rotates the shaft 21 in a rotation direction r4 opposite to the rotation direction r3, the belt E1 rotates in the direction of arrow R4. The rotational power of the belt E1 is output to a first hollow shaft 61 (described below) of the multiple shaft 6 via a belt E11.

[0063] 12 and 13, the second mechanism 52 included in the operating mechanism 50 includes a belt E2 that transmits power for raising and lowering the robot wrist 7, a support unit 520, and a drive unit 526 (see FIG. 20). The second mechanism 52 is generally disposed in the right portion (+Y-axis direction with respect to the imaginary plane AP) within the arm housing 40. As shown in FIG. 10, the belt E2 is disposed in the upper right portion of the first region Ar1.

[0064] The belt E2 is disposed symmetrically with the arm extension / retraction belt 471 with respect to the imaginary plane AP. The support unit 520 includes shafts 22 and 23 provided at the base end 404. The shafts 22 and 23 are disposed side by side in the Y-axis direction. The support unit 520 includes a rotor 323 provided at the shaft 22 and rotated by the rotation of the shaft 22, and a rotor 333 that is rotatable relative to the shaft 23. Furthermore, at the front end 43f of the tip housing 41, the intermediate housing 42, and the base housing 43, the support unit 520 includes shafts and rotors that are disposed symmetrically with respect to the imaginary plane AP with the shafts and rotors provided at the support unit 48. The configuration of these shafts and rotors in the support unit 520 is similar to that of the shafts and rotors in the support unit 48, except that they are disposed symmetrically with respect to the imaginary plane AP, and therefore description thereof will be omitted.

[0065] 13 and 20 , a motor M2 for lifting and lowering the wrist is operably connected to the shaft 22. The motor M2 is provided at the base end 404. The motor M2 is included in the drive unit 526. The shaft 22 is also a drive shaft that is operably connected to the motor M2 and outputs the power of the motor M2. Therefore, the shaft 22 can also be considered as part of the drive unit 526.

[0066] The second mechanism 52 further includes a belt E21 disposed at the free end 405. The belt E21 is stretched between a rotating body 485 provided on the shaft 481f of the support portion 520 and a rotating body provided on the multiple shaft 6 provided at the free end 405.

[0067] 14, the belt E2 rotates in the direction of arrow R5. When the motor M2 for lifting the wrist rotates the shaft 22 in a rotation direction r6 opposite to the rotation direction r5, the belt E2 rotates in the direction of arrow R6. The rotational power of the belt E2 is output to a second hollow shaft 62 (described below) in the multiple shaft 6 via a belt E21.

[0068] 12 and 13, the third mechanism 53 included in the operation mechanism 50 includes a belt E3 that transmits power for causing the hand 190 to perform a pitch operation via the robot wrist 7, a support unit 530, and a drive unit 536 (see FIG. 20). The support unit 530 is configured to support the belt E3 on the arm housing 40 in the −Z-axis direction of the belt E2.

[0069] As shown in FIG. 10 , the belt E3 is disposed symmetrically to the wrist rotation belt E1 with respect to the imaginary plane AP. As shown in FIG. 13 , the support unit 530 includes shafts 22 and 23 provided at the base end 404. The support unit 530 further includes a rotating body 322 that is rotatable relative to the shaft 22 and a rotating body 331 that is provided on the shaft 23 and rotates with the rotation of the shaft 23. Furthermore, at the front ends of the distal housing 41, the intermediate housing 42, and the proximal housing 43, the support unit 530 includes shafts and rotating bodies that are disposed symmetrically with respect to the imaginary plane AP with the shafts and rotating bodies provided in the support unit 510. The configurations of these shafts and rotating bodies in the support unit 530 are similar to those of the shafts and rotating bodies in the support unit 510, except that they are disposed symmetrically with respect to the imaginary plane AP, and therefore, description thereof will be omitted.

[0070] 13 and 20 , a motor M3 for pitch operation is operably connected to the shaft 23. The motor M3 is provided at the base end 404. The motor M3 is included in the drive unit 536. The shaft 23 is also a drive shaft that is operably connected to the motor M3 and outputs the power of the motor M3. Therefore, the shaft 23 can also be considered as part of the drive unit 536.

[0071] The third mechanism 53 further includes a belt E31. The belt E31 is stretched between a rotating body 515 provided on the shaft 481f of the support portion 530 and the multiple shafts 6 provided on the free end portion 405. As shown in FIGS. 12, 13, and 18, the belt E31 is disposed between the belts E21 and E11 in the Z-axis direction.

[0072] When the pitch motor M3 rotates the shaft 23 in a rotational direction r7, the belt E3 rotates in the direction of arrow R7. When the motor M3 rotates the shaft 23 in a rotational direction r8 opposite to the rotational direction r7, the belt E3 rotates in the direction of arrow R8. The rotational power of the belt E3 is output to a third hollow shaft 63 (described below) in the multiple shaft 6 via a belt E31.

[0073] As described above, the belt 471 of the extension / retraction mechanism 47 and the belts E1, E2, and E3 of the operating mechanism 50 are disposed within the arm housing 40. The support portion 48 of the extension / retraction mechanism 47 and the support portion 510 of the first mechanism 51 are disposed primarily in the left portion of the first region Ar1. Most of the shafts of the support portion 48 are also used as the shafts of the support portion 510. Therefore, the belt E1 can be disposed below the belt 471. In other words, the belt 471 and the belt E1 can be disposed side by side in the Z axis direction. Furthermore, the support portion 520 of the second mechanism 52 and the support portion 530 of the third mechanism 53 are disposed primarily in the right portion of the first region Ar1. Most of the shafts of the support portion 520 are also used as the shafts of the support portion 530. Therefore, the belt E3 can be disposed below the belt E2. In other words, the belts E2 and E3 can be disposed side by side in the Z axis direction. In this way, in the robot arm 4 of this embodiment, the space inside the arm housing 40 can be effectively utilized, and multiple belts can be arranged inside the arm housing 40.

[0074] Since the belts 471, E1, E2, and E3 are disposed within the arm housing 40, for example, when the belt 471 is driven by the motor M, the other belts E1, E2, and E3 may also rotate in response to the extension and retraction of the arm housing 40. This may result in the end effector being unintentionally operated by the first mechanism 51, the second mechanism 52, and the third mechanism 53. In this embodiment, the robot 1 includes the control mechanism 20, which allows the extension and retraction of the arm housing 40 to be performed independently by the motor M alone, the rotation of the robot wrist 7 to be performed independently by the motor M1 alone, the lifting and lowering of the robot wrist 7 to be performed independently by the motor M2 alone, and the pitching of the robot wrist 7 to be performed independently by the motor M3 alone. Details of the control mechanism 20 will be described later. In other embodiments, for example, the robot control device 10 may synchronously control the motors M, M1, M2, and M3 so that the first mechanism 51, the second mechanism 52, and the third mechanism 53 do not follow the extension and retraction of the robot arm 4.

[0075] <Adjustment Unit> The robot arm 4 of this embodiment further includes an adjustment unit 54 configured to be able to adjust the tension of the belt. The adjustment unit 54 is provided for each of the belt 471, the belt E1, the belt E2, and the belt E3.

[0076] 12, the adjustment portion 54 of the belt 471 is provided at the front end 43f (protrusion 433) of the left portion of the base housing 43. The adjustment portion 54 of the belt E1 is provided at the front end 42f (protrusion 423) of the left portion of the intermediate housing 42. The adjustment portions 54 of the belts E2 and E3 are provided in positions symmetrical to the adjustment portions 54 of the belts 471 and E1 with respect to the imaginary plane AP.

[0077] 16 and 17 show the adjustment unit 54 for the belt 471. The adjustment unit 54 adjusts the position (position in the X-axis direction) of the shaft 483f that rotatably holds the belt 471, thereby adjusting the tension of the belt 471. The adjustment unit 54 mainly includes a holding unit 541 and an adjustment shaft 548.

[0078] The holding portion 541 is provided at the front end portion 43f of the base housing 43. As shown in Fig. 16, the holding portion 541 is provided with a recess (groove) 542 that opens in the -X axis direction and in which the rotor 485 can be placed. The shaft 483f that supports the belt 471 is fixed to the holding portion 541 so as to pass through the recess 542 in the Z axis direction. In this embodiment, the holding portion 541 is disposed in a recess (groove) 543 that opens in the -X axis direction in the protruding portion 433.

[0079] A through-hole 546 extending in the X-axis direction is provided in the front end 43f of the base-end housing 43. The through-hole 546 penetrates a front-end wall 545 that defines the base-end housing 43. A hole 544 that communicates with the through-hole 546 is provided in the front end of the holding portion 541. The through-hole 546 and the hole 544 are configured to screw into the shaft portion of the adjustment shaft 548. The through-hole 546 and the hole 544 form a "hole portion" through which the shaft portion of the adjustment shaft 548 is inserted. The axis of the adjustment shaft 548 is coaxial with the axis of the hole portion.

[0080] The holder 541 moves in the X-axis direction as the adjustment shaft 548 rotates in a predetermined direction around its axis. Therefore, by rotating the adjustment shaft 548, the user can move the shaft 483f in the X-axis direction via the holder 541. This allows the user to adjust the tension of the belt 471 from outside the arm housing 40. Similarly, the user can adjust the tension of each belt by adjusting the adjustment units 54 corresponding to the belts E1, E2, and E3. For example, the tension of the belt E1 can be adjusted by moving the shaft 511 in the X-axis direction via the holder 541 at the front end 42f of the intermediate housing 42. Similarly, the tension of the belts E2 and E3 can be adjusted by moving the shafts 483f and 511 in the X-axis direction via the shafts 483f and 511, to which the adjustment units 54 are attached.

[0081] <Multiple Shaft> Next, the multiple shaft 6 will be described mainly using FIGS. 18 and 19 . The multiple shaft 6 is provided at the free end 405 of the robot arm 4. The multiple shaft 6 extends in the Z-axis direction. The multiple shaft 6 includes a first portion 601 disposed within the tip housing 41 and a second portion 602 protruding from the tip housing 41 in the −Z-axis direction. As shown in FIG. 19 , the second portion 602 is disposed within the wrist housing 70. The first portion 601 of the multiple shaft 6 is operably coupled to the belts E1, E2, and E3 of the operating mechanism 50, and is configured to input the rotational power of the belts E1, E2, and E3, respectively. Furthermore, the second portion 602 of the multiple shaft 6 is configured to output the rotational power of the belts E1, E2, and E3, respectively.

[0082] The multiple shaft 6 includes multiple hollow shafts. As shown in FIG. 18 , in this embodiment, the multiple shaft 6 includes three hollow shafts: a first hollow shaft 61 for wrist rotation, a second hollow shaft 62 for wrist lifting, and a third hollow shaft 63 for pitch movement. The central axes AX61, AX62, and AX63 of the first hollow shaft 61, second hollow shaft 62, and third hollow shaft 63 extend in the Z-axis direction. The central axis AX61 of the first hollow shaft 61 also serves as the rotation axis T of the robot wrist 7. The central axes AX61, AX62, and AX63 are coaxial. The diameters of the hollow shafts are different from one another. The lengths of the hollow shafts are also different from one another.

[0083] In this embodiment, the second hollow shaft 62 has the smallest diameter and the first hollow shaft 61 has the largest diameter. The third hollow shaft 63 is disposed radially outward of the second hollow shaft 62, and the first hollow shaft 61 is disposed radially outward of the third hollow shaft 63. Furthermore, the length of the hollow shafts in the Z-axis direction is longest for the second hollow shaft 62 and shortest for the first hollow shaft 61. In the first portion 601, the upper end 62u of the second hollow shaft 62, the upper end 63u of the third hollow shaft 63, and the upper end 61u of the first hollow shaft 61 are located in this order in the -Z-axis direction. In the second portion 602, the lower end 62d of the second hollow shaft 62, the lower end 63d of the third hollow shaft 63, and the lower end 61d of the first hollow shaft 61 are located in this order in the +Z-axis direction.

[0084] The upper end 62u and the lower end 62d of the second hollow shaft 62 are not covered by the first hollow shaft 61 and the third hollow shaft 63. The upper end 63u and the lower end 63d of the third hollow shaft 63 are not covered by the first hollow shaft 61 and the second hollow shaft 62. The upper end 61u and the lower end 61d of the first hollow shaft 61 are not covered by the second hollow shaft 62 and the third hollow shaft 63. In other words, the first hollow shaft 61, the second hollow shaft 62, and the third hollow shaft 63 have portions in the first portion 601 and the second portion 602 that are not covered by the other hollow shafts.

[0085] As shown in FIG. 18 , a rotating body 621 is provided at the upper end 62u of the second hollow shaft 62. As shown in FIG. 19 , a rotating body 622 is provided at the lower end 62d of the second hollow shaft 62. The rotating body 621 is disposed in the first section 601, and the rotating body 622 is disposed in the second section 602, inside the wrist housing 70. The rotating bodies 621 and 622 are fixed to the second hollow shaft 62 and rotate integrally with the second hollow shaft 62. A belt E21 of the second mechanism 52 is stretched around the rotating body 621. Rotation of the belt E2 provided in the second mechanism 52 is transmitted in the following order: the rotating body 485 provided on the shaft 481f of the support portion 520, the belt E21, the rotating body 621, the second hollow shaft 62, and the rotating body 622. The rotation of the rotating body 622 drives the belt E22 provided in the robot wrist 7. The rotating body 621 and the belt E21 function as a transmission unit that transmits the rotation of the belt E2 to the second hollow shaft 62.

[0086] The third hollow shaft 63 is disposed radially outside the second hollow shaft 62 via a bearing 605d. A rotating body 631 is provided at an upper end 63u of the third hollow shaft 63. A rotating body 632 is provided at a lower end 63d of the third hollow shaft 63. The rotating bodies 631 and 632 are fixed to the third hollow shaft 63 and rotate integrally with the third hollow shaft 63. A spacer 606 is disposed between the rotating body 622 and the rotating body 632 in the Z-axis direction. The rotating body 631 is disposed in the first portion 601, and the rotating body 632 is disposed in the second portion 602, inside the wrist housing 70. A belt E31 of the third mechanism 53 is wound around the rotating body 631. The rotation of the belt E3 included in the third mechanism 53 is transmitted in this order to the rotating body 515 provided on the shaft 481f of the support unit 530, the belt E31, the rotating body 631, the third hollow shaft 63, and the rotating body 632. The rotation of the rotating body 632 drives the belt E32 included in the robot wrist 7. The rotating body 631 and the belt E31 function as a transmission unit that transmits the rotation of the belt E3 to the third hollow shaft 63.

[0087] The first hollow shaft 61 is disposed radially outside the third hollow shaft 63 via a bearing 605u. The upper end 61u and the lower end 61d of the first hollow shaft 61 are disposed between the upper end 63u and the lower end 63d of the third hollow shaft 63 in the Z-axis direction. A rotating body 611 is provided at the upper end 61u of the first hollow shaft 61. The rotating body 611 is disposed in the first portion 601 and rotates integrally with the first hollow shaft 61. A belt E11 of the first mechanism 51 is stretched around the rotating body 611. The rotation of the belt E1 of the first mechanism 51 is transmitted to the first hollow shaft 61 via the rotating body 515, the belt E11, and the rotating body 611, which are provided on the shaft 481f of the support portion 510. The rotating body 611 and the belt E11 function as a transmission unit that transmits the rotation of the belt E1 to the first hollow shaft 61.

[0088] A flange 613 is provided at the lower end 61d of the first hollow shaft 61. The flange 613 is connected to the shaft body of the first hollow shaft 61 and protrudes in a direction away from the central axis T. The bottom of the tip housing 41 is disposed radially outside the first hollow shaft 61, between the rotating body 611 and the flange 613 in the Z-axis direction.

[0089] 19, the flange 613 protruding from the tip housing 41 is fixed to an upper wall 701u of the wrist housing 70. Therefore, when the first hollow shaft 61 rotates, the wrist housing 70 rotates (pivots) around the pivot axis T.

[0090] In the robot arm 4 described above, the first area Ar1 in which the belts 471, E1, E2, and E3 are arranged and the second area Ar2 in which the guide portion 45 that guides the extension and retraction of the arm housing 40 is arranged do not overlap in the Z-axis direction. This prevents the assembly of the robot arm 4 from becoming complicated. Furthermore, interference between the belts 471, E1, E2, and E3 and the guide portion 45 is prevented.

[0091] Furthermore, since the electric motors M, M1, M2, and M3 are disposed at the base end 404, the mass at the free end 405 of the robot arm 4 is reduced, thereby improving the operability of the robot arm 4. Furthermore, the power required for the operation of the robot arm 4 is reduced.

[0092] The robot arm 4 has a multiple shaft 6 provided at the free end 405. In the first portion 601 of the multiple shaft 6, the rotational power of the belts E1, E2, and E3 is input to the first hollow shaft 61, the second hollow shaft 62, and the third hollow shaft 63, respectively. In the second portion 602 of the multiple shaft 6, the rotational power of the belts E1, E2, and E3 is output to the robot wrist 7 from the first hollow shaft 61, the second hollow shaft 62, and the third hollow shaft 63, respectively. Therefore, compared to a configuration in which an input shaft and an output shaft are provided for each of the belts E1, E2, and E3, the configuration of the robot arm 4 is less complicated. Furthermore, the assembly of the robot arm 4 is less complicated. Furthermore, the robot arm 4 can be prevented from becoming large while arranging multiple belts 471, E1, E2, and E3 within the arm housing 40.

[0093] In the first area Ar1 of the arm housing 40, the belt E2 and the support portion 520 are disposed symmetrically to the belt 471 and the support portion 48 with respect to the imaginary plane AP. Furthermore, the belt E1 is disposed directly below the belt 471, and the belt E3 is disposed directly below the belt E2. This allows the space within the arm housing 40 to be used effectively. This prevents the robot arm 4 from becoming too large.

[0094] Furthermore, the shaft in the support section 48 of the telescopic mechanism 47 is also used as the shaft in the support section 510 of the first mechanism 51, and the shaft in the support section 520 of the second mechanism 52 is also used as the shaft in the support section 530 of the third mechanism 53. Therefore, it is possible to arrange multiple belts 471, E1, E2, E3 inside the arm housing 40 while suppressing an increase in the number of parts that make up the robot arm 4.

[0095] The robot arm 4 is provided with adjustment units 54 at the front end 42 f of the intermediate housing 42 and the front end 43 f of the base end housing 43. Therefore, the tension of the belts 471, E1, E2, and E3 can be adjusted from outside the robot arm 4, improving the maintainability of the robot arm 4.

[0096] The robot arm 4 also includes a cable housing 44 disposed in the third area Ar3 above the belts 471, E1, E2, and E3. This reduces interference between the cables and the multiple belts. The inside of the cable housing 44 communicates with the outside at the base end 404. The inside of the cable housing 44 also communicates with the inside of the second hollow shaft 62 at the free end 405. This reduces interference between the cables, the belts 471, E1, E2, and E3, and the guide portion 45 while arranging the cables within the arm housing 40. This also protects the cables better than a configuration in which the cables are arranged outside the robot arm 4.

[0097] <Other Embodiments of the Robot Arm> The arm housing 40 only needs to have a telescopic structure including a distal housing 41 and a proximal housing 43, and the number of housings included in the arm housing 40 is not limited to that in the above embodiment. For example, the arm housing 40 does not need to have an intermediate housing 42. Alternatively, the arm housing 40 may have two or more intermediate housings 42. In this case, it is only necessary that the intermediate housing located in the −X-axis direction is configured to accommodate the intermediate housing located in the +X-axis direction so as to be able to move forward and backward.

[0098] The robot arm 4 may include movement mechanisms in a number corresponding to the degrees of freedom of the end effector. For example, the robot arm 4 may have only the first mechanism 51 or only the second mechanism 52 as the movement mechanism 50. Alternatively, the robot arm 4 may include four or more movement mechanisms as the movement mechanism 50. For example, further movement mechanisms may be provided below the first mechanism 51 and below the third mechanism 53.

[0099] The multiple shafts of the support unit 48 and the multiple shafts of the support unit 510 may all be shared. For example, the shaft 483f of the support unit 48 may extend in the Z-axis direction and be used as the shaft 512 of the support unit 510. In this case, the adjustment unit 54 may be configured to adjust the tension of the belt 471 and the belt E1 by moving the shaft 483f in the X-axis direction.

[0100] The area Ar2 in which the guide portion 45 is accommodated may be different in the Z-axis direction from the area Ar1 in which the belts 471, E1, E2, and E3 are accommodated. For example, the area Ar2 may be disposed above the area Ar1 (positive Z-axis direction).

[0101] The belts 471, E1, E2, E3, E11, E21, and E31 may be endless members, and may be timing belts or chains.

[0102] <Robot Wrist> Next, the robot wrist 7 will be described using FIGS. 19 and 21 to 37. The robot wrist 7 is configured to be capable of performing an elevation operation that raises and lowers an end effector of the robot wrist 7 in the Z-axis direction and a pitch operation that rotates the end effector about the pitch axis P. In this embodiment, the end effector of the robot wrist 7 is a hand 190. The robot wrist 7 mainly includes a wrist housing 70 extending in the X1-axis direction, an elevation operation unit 8, and a pitch operation unit 9 (see FIG. 30). The elevation operation unit 8 includes a belt E22, a second hollow shaft 62 serving as a drive shaft that drives the belt E22, a driven shaft 72, and a link mechanism 80. The pitch operation unit 9 includes a belt E32, a third hollow shaft 63 serving as a drive shaft that drives the belt E32, the driven shaft 72, and a transmission mechanism 91.

[0103] The lifting operation unit 8 moves the attachment unit 191 along the Z-axis direction using the link mechanism 80, thereby moving the hand 190 (attachment unit 191) along the Z-axis direction. Figures 22 to 24 show the robot wrist 7 when the attachment unit 191 is in its highest position. Figures 27 and 28 show the robot wrist 7 when the attachment unit 191 is in its lowest position. Hereinafter, the highest position of the attachment unit 191 will be referred to as the "highest position," and the lowest position of the attachment unit 191 will be referred to as the "lowest position." The position of the attachment unit 191 in the Z-axis direction changes between the highest position and the lowest position. The robot wrist 7 has a pitch axis P, which is the rotation axis of the attachment unit 191. The pitch axis P extends in the Y1-axis direction, which is perpendicular to the X1-axis direction and the Z-axis direction. The pitch operation unit 9 rotates the hand 190 around the pitch axis P using a transmission mechanism 91.

[0104] In FIG. 21 and the following figures, the X1-axis, Y1-axis, and Z-axis directions are indicated as appropriate. The +X1-axis direction is the direction from the base end 704 to the tip end 705 of the wrist housing 70, and the −X1-axis direction is the opposite direction to the +X1-axis direction. With respect to the robot wrist 7, the +X1-axis direction is also referred to as the forward direction, and the −X1-axis direction is also referred to as the rearward direction. The Z-axis direction is the extension direction of the axis of the multiple shaft 6 and, in this embodiment, is the up-down direction. The +Z-axis direction is the upward direction, and the −Z-axis direction is the downward direction. The Y1-axis direction is a direction perpendicular to the +X1-axis and Z-axis directions. With respect to the robot wrist 7, the right direction when looking at the robot wrist 7 from the base end 704 in the +X1-axis direction is also referred to as the +Y1-axis direction, and the opposite direction is also referred to as the −Y1-axis direction. Note that in FIG. 21, the X1-axis direction is the same as the X-axis direction, which is the extension and retraction direction of the robot arm 4; however, when the robot wrist 7 rotates, the X1-axis direction and the X-axis direction differ. In addition, in FIG. 21, the Y1 axis direction is the same as the Y axis direction, but when the robot wrist 7 turns, the Y1 axis direction differs from the Y axis direction.

[0105] <Wrist Housing> The wrist housing 70 extends in the X1-axis direction. The X1-axis direction is perpendicular to the Z-axis direction, which is the extension direction of the axis T (AX61, AX62, AX63) of the multiple shafts 6. As shown in FIG. 21 , the wrist housing 70 is attached at its base end 704 to the free end 405 of the robot arm 4. As shown in FIGS. 19 and 22 , the upper wall 701u of the wrist housing 70 is fixed to the flange 613 of the first hollow shaft 61. The robot wrist 7 rotates around the rotation axis T together with the first hollow shaft 61.

[0106] 23 and 26, the wrist housing 70 is formed in a substantially rectangular parallelepiped shape with an opening 702 in a lower wall 701d. The lower wall 701d defines the bottom of the wrist housing 70. A portion of the link mechanism 80 is exposed from the opening 702.

[0107] 31 and 32 , a sensor housing 706 is provided at the tip 705 of the wrist housing 70. The sensor housing 706 is separated from the belt housing 703, which houses the belts E22 and E32, by a partition wall 706b perpendicular to the X1 axis direction. The sensor housing 706 houses sensors for operating the robot 1, such as a distance sensor, a camera, and a touch sensor. An opening 705a for the sensor arranged in the sensor housing 706 is provided in the front end wall 701f of the wrist housing 70. The front end wall 701f is configured to be detachable from the partition wall 706b.

[0108] <Internal Configuration of Wrist Housing> Next, the internal configuration of the wrist housing 70 will be described. As shown in FIGS. 19 , 31 , and 32 , the base end 704 of the wrist housing 70 accommodates the second hollow shaft 62 and the second portion 602 of the third hollow shaft 63. The third hollow shaft 63 is disposed radially outward of the second hollow shaft 62 via a bearing 605. The lower end 63d of the third hollow shaft 63 is located above the lower end 62d of the second hollow shaft 62. The second hollow shaft 62 is provided with a rotating body 622 that rotates integrally with the second hollow shaft 62. The third hollow shaft 63 is provided with a rotating body 632 that rotates integrally with the third hollow shaft 63. As described above, the second hollow shaft 62 functions as a drive shaft for the lifting operation unit 8. The third hollow shaft 63 functions as a drive shaft for the pitch operation unit 9.

[0109] 31 and 32 , a driven shaft 72 is housed in the tip portion 705 of the wrist housing 70. The axis AX72 of the driven shaft 72 extends in the Z-axis direction. The driven shaft 72 is fixed to the wrist housing 70. In this embodiment, the driven shaft 72 is held by a holding member 741 provided around the driven shaft 72. The holding member 741 is fixed to the partition wall 706b via an adjustment shaft 742. As described above, the driven shaft 72 functions as a driven shaft for the lifting operation unit 8 and the pitch operation unit 9.

[0110] A rotating body 722 is provided at the lower end of the driven shaft 72. The rotating body 722 is rotatably supported on the driven shaft 72 via a bearing. The rotating body 722 provided on the driven shaft 72 and the rotating body 622 provided on the second hollow shaft 62 are positioned approximately the same in the Z-axis direction. A belt E22 for lifting the wrist is stretched between the rotating body 622 and the rotating body 722.

[0111] A rotating body 732 is provided at the upper end of the driven shaft 72. The rotating body 732 is rotatably supported on the driven shaft 72 via a bearing. The rotating body 732 provided on the driven shaft 72 and the rotating body 632 provided on the third hollow shaft 63 are positioned approximately the same in the Z-axis direction. A belt E32 for pitch movement is stretched between the rotating body 632 and the rotating body 732.

[0112] The partition wall 706b is provided with a through-hole 706h that penetrates in the X-axis direction. The adjustment shaft 742 is configured to be insertable into the front end of the holding member 741 through the through-hole 706h. The user adjusts the amount of protrusion (insertion amount) of the adjustment shaft 742 into the holding member 741, thereby moving the position of the holding member 741 in the X1-axis direction. This allows the driven shaft 72 to move in the X1-axis direction, thereby adjusting the tension of the belts E22 and E32. The adjustment shaft 742, the partition wall 706b (through-hole 706h), and the holding member 741 constitute an adjustment unit that adjusts the tension of the belts E22 and E32.

[0113] As shown in Figures 26, 29, and 30, rails 707u and 707d extending in the X1-axis direction are provided within the wrist housing 70. The rails 707d are fixed to the lower parts of the left and right side walls 701s of the wrist housing 70. The rail 707u is fixed to the upper part of the left side wall 701s of the wrist housing 70. The position of the rail 707u in the Z-axis direction is approximately the same as that of the belt E32. The position of the rail 707d in the Z-axis direction is approximately the same as that of the belt E22. Carriages 806 and 805, each having a groove extending in the X-axis direction, are slidably supported on the rails 707u and 707d. The carriages 806 and 805 will be described later.

[0114] 27 to 34 , the lifting operation unit 8 will be described. The lifting operation unit 8 includes a second hollow shaft 62, a driven shaft 72, a rotating body 622 provided on the second hollow shaft 62, a rotating body 722 provided on the driven shaft 72, a belt E22 stretched between the rotating body 622 and the rotating body 722, and a link mechanism 80.

[0115] The link mechanism 80 is driven by the belt E22. The link mechanism 80 includes a first link portion 81 and a second link portion 84. The link mechanism 80 is configured as a Scott Russell link.

[0116] 26 , 27 , 31 , and 32 , the first link portion 81 includes a casing 810 extending in a predetermined direction. The casing 810 has a first end 814 in the extension direction and a second end 815 that is the end opposite the first end 814 (see FIG. 33 ). The first end 814 is located on the base end 704 side of the wrist housing 70 in the fully raised state. The second end 815 is located on the tip end 705 side of the wrist housing 70 in the fully raised state. As shown in FIG. 26 , the casing 810 is spaced apart from the left and right side walls 701s of the wrist housing 70 in the Y1 axis direction.

[0117] The casing 810 includes a bottom wall 811d in the -Z-axis direction and a pair of side walls 811s connected to the bottom wall 811d and perpendicular to the Y1-axis direction. The side walls 811s of the casing 810 function as the long links in a Scott Russell link. As shown in Figures 31 and 32, the casing 810 further includes an upper cover 811c connected to the side walls 811s. The upper cover 811c is omitted as appropriate in figures other than Figures 31 and 32.

[0118] 29 to 31 , the first end 814 is provided with a moving joint shaft 812, a right holding block 803, a left holding block 804, and a belt clamp 808. The right holding block 803 is provided in the +Y1 axis direction of the belt E22. The right holding block 803 holds the end (right end) of the moving joint shaft 812 in the +Y1 axis direction. The right end of the moving joint shaft 812 holds the right side wall 811s of the casing 810. The moving joint shaft 812 functions as a moving joint in a Scott-Russell link.

[0119] The left holding block 804 is provided in the -Y1 axis direction of the belts E22 and E32. The left holding block 804 holds the end (left end) of the moving link shaft 812 in the -Y1 axis direction. The left end of the moving link shaft 812 holds the left side wall 811s of the casing 810. The left holding block 804 has an extending portion 804d extending in the X1 axis direction at its lower portion, and protruding portions 804f and 804b protruding upward from the extending portion 804d. The extending portion 804d is located in the -Y1 axis direction of the belt E22. The protruding portions 804f and 804b are located in the -Y1 axis direction of the belt E32. The protruding portion 804f protrudes upward from the front end of the extending portion 804d, and the protruding portion 804b protrudes upward from the rear end of the extending portion 804d. The protrusion 804f and the protrusion 804b are spaced apart in the X1 axis direction.

[0120] The belt E22 is fixed to the extension portion 804d of the left holding block 804 by a belt clamp 807. As described above, the left holding block 804 holds the moving joint shaft 812, and the first end portion 814 (side wall 811s) of the moving joint shaft 812 is held. Therefore, when the belt E22 rotates, the first end portion 814 and the moving joint shaft 812 move integrally with the left holding block 804 in the X1 axis direction.

[0121] Note that a carriage 805 is fixed to each of the extension portions 804d of the right holding block 803 and the left holding block 804. As described above, the carriage 805 is slidably supported on rails 707d provided on the left and right side walls 801s of the wrist housing 70. The carriage 805 and the rails 707d guide the movement of the holding blocks 803 and 804 in the X1 axis direction. In other words, the carriage 805 and the rails 707d guide the movement of the first end 814 and the moving link shaft 812 in the X1 axis direction.

[0122] A tip node shaft 822 extending in the Y1-axis direction is provided at the second end 815 of the first link portion 81 (casing 810). Both ends of the tip node shaft 822 are supported by the side wall 811s and protrude from the side wall 811s in the +Y1-axis direction and the -Y1-axis direction. The mounting portion 191 is fixed non-rotatably to the tip node shaft 822 and rotates integrally with the tip node shaft 822. The axis AX822 of the tip node shaft 822 is also the pitch axis P. The second end 815 of the side wall 811s and the tip node shaft 822 function as the tip node of the Scott-Russell link.

[0123] The second link portion 84 functions as a short link in the Scott-Russell link. As shown in FIGS. 29 and 33 , a base end 841 of the second link portion 84 is disposed within the wrist housing 70. The base end 841 is supported on the wrist housing 70 at the tip end 705 of the wrist housing 70 by a shaft 843. A connecting end 842 of the second link portion 84 opposite the base end 841 is supported on the side wall 811s of the casing 810 by a shaft 844. The connecting end 842 and the shaft 844 are located approximately midway between the axis AX812 of the moving link shaft 812 and the axis AX822 of the tip link shaft 822. The axes AX843 and AX844 of the shafts 843 and 844 are parallel to the Y1 axis. The base end 841 and the connecting end 842 are rotatable about the axes AX843 and AX844, respectively. The connecting end 842 and the shaft 844 function as a first connecting joint of the present disclosure, and the proximal end 841 and the shaft 843 function as a second connecting joint of the present disclosure.

[0124] 33 , the shaft 843 (axis AX843) at the base end 841 of the second link unit 84 is located at approximately the same position in the Z-axis direction as the moving joint shaft 812 (axis AX812) of the first link unit 81. Furthermore, the moving joint shaft 812 (axis AX812), the shaft 844 (axis AX844) of the second link unit 84, and the distal joint shaft 822 (axis AX822) of the first link unit 81 are all on a predetermined collinear line. The distance between the axes AX843 and AX844, the distance between the axes AX844 and AX812, and the distance between the axes AX844 and AX822 are all equal.

[0125] The operation of the link mechanism 80 will be described with reference to Figures 33 and 34. For example, as shown in Figure 33, when the robot wrist 7 is in the highest position, the motor M2 rotates the shaft 22 in the direction of arrow r5 shown in Figure 14, causing the belt E2 to rotate in the direction of arrow R5. This causes the second hollow shaft 62 of the lifting operation unit 8 to rotate due to the rotation of the belt E21, causing the belt E22 to rotate in the direction of arrow R51 shown in Figure 33. As a result, the left holding block 804, the first end 814 of the first link unit 81, and the movable joint shaft 812 move in the +X1 axis direction together with the belt clamp 807 fixed to the belt E22. As the movable joint shaft 812 moves in the +X1 axis direction, the base end 841 and the connecting end 842 of the second link unit 84 rotate in the direction of arrow r51 around the axes AX843 and AX844, respectively. As a result, the second end 815 of the first link unit 81 and the tip joint shaft 822 are moved in the −Z-axis direction, and the robot wrist 7 transitions to the lowest position shown in Fig. 34. As the first end unit 814 and the movable joint shaft 812 move in the +X1-axis direction, the first link unit 81 and the second link unit 84 are exposed to the outside through the opening 702 in the wrist housing 70.

[0126] Furthermore, when the robot wrist 7 shown in FIG. 34 is in the lowest position, the motor M2 rotates the shaft 22 in the rotation direction r6 shown in FIG. 14, causing the belt E2 to rotate in the direction of arrow R6. This causes the second hollow shaft 62 of the lifting operation unit 8 to rotate the belt E22 in the direction of arrow R61 ( FIG. 34 ), which is the opposite direction to arrow R51. As a result, the left holding block 804, the first end 814 of the first link unit 81, and the movable joint shaft 812 move together with the belt clamp 807 fixed to the belt E22 in the −X1 axis direction. Due to the displacement of the first link unit 81, the base end 841 and the connecting end 842 of the second link unit 84 rotate in the direction of arrow r61 around the axes AX843 and AX844, respectively. As a result, the second end 815 of the first link unit 81 moves in the +Z axis direction, and the robot wrist 7 transitions to the highest position shown in FIG. 33. The first link portion 81 and the second link portion 84 are housed inside the wrist housing 70 through the opening 702 of the wrist housing 70 as the first end portion 814 and the moving link shaft 812 move in the −X1 axis direction.

[0127] 29, 30, and 35 to 37, the pitch movement unit 9 will be described. The pitch movement unit 9 includes a belt E32, a third hollow shaft 63 serving as a drive shaft for driving the belt E32, a driven shaft 72, and a transmission mechanism 91.

[0128] The transmission mechanism 91 is configured to transmit the rotation of the belt E32 to the belt E33. The transmission mechanism 91 includes a moving node shaft 812 as a drive shaft, a tip node shaft 822 as a driven shaft, the belt E33, a rack gear 921, and a pinion gear 931. In this embodiment, the moving node shaft 812 included in the moving node of the link mechanism 80 and the tip node shaft 822 included in the tip node are used as both the drive shaft and the driven shaft of the pitch movement unit 9.

[0129] As shown in FIG. 31 , a rotating body 912 is provided on the moving link shaft 812. The rotating body 912 is fixed to the moving link shaft 812 and rotates integrally therewith. A rotating body 922 is provided on the distal link shaft 822. The rotating body 922 is fixed to the distal link shaft 822 and rotates integrally therewith. The rotating bodies 912 and 922 are toothed pulleys. A belt E33 is stretched between the rotating bodies 912 and 922. As described above, the moving link shaft 812 is provided at the first end 814 of the first link unit 81 (casing 810), and the distal link shaft 822 is provided at the second end 815 of the first link unit 81. The belt E33 is disposed within the casing 810 and is rotatable within the casing 810. Inside the casing 810, there are arranged a support shaft and a driven rotor that is attached to the support shaft and supports the rotation of the belt E33.

[0130] As shown in Figures 29, 30, and 35, the rack gear 921 is fixed to the belt clamp 808, which is fixed to the belt E32. The teeth of the rack gear 921 are arranged in the -Z-axis direction. The belt clamp 808 is fixed to the carriage 806 via a block member 808m. The carriage 806 is disposed between the protrusions 804f and 804b of the left holding block 804 in the X1-axis direction, and is slidably supported by the rail 707u. When the belt E32 rotates, the rack gear 921 fixed to the belt clamp 808 moves in the X1-axis direction. The carriage 806 and the rail 707u guide the movement of the rack gear 921 in the X1-axis direction. The movement of the carriage 806 in the X1-axis direction is restricted by the protrusions 804f and 804b. Therefore, movement of the rack gear 921 in the +X1 axis direction is restricted by the protrusion 804f, and movement of the rack gear 921 in the -X1 axis direction is restricted by the protrusion 804b. The protrusions 804f and 804b of the left holding block 804 function as restricting portions that restrict movement of the rack gear 921 in the X1 axis direction. The left holding block 804 supports the moving joint shaft 812 at approximately the middle portion of the extension portion 804d in the X1 axis direction. Therefore, the rack gear 921 moves on the moving joint shaft 812 in the X1 axis direction.

[0131] The pinion gear 931 is provided on the moving node shaft 812 so as to mesh with the rack gear 921. In this embodiment, the pinion gear 931 rotates integrally with the moving node shaft 812. In this embodiment, the pinion gear 931 is an intermittent gear. The length (circumferential length) of the gear around the axis AX812 corresponds to the length of the rack gear 921 in the X1 axis direction. In other embodiments, the pinion gear 931 does not have to be an intermittent gear. As the rack gear 921 and the pinion gear 931 mesh with each other, the linear motion of the rack gear 921 in the X1 axis direction is converted into rotational motion about the axis AX812 of the rotating body 932 on which the pinion gear 931 is provided. The relative displacement of the belts E32 and E22 in the X1 axis direction is converted into rotational motion of the moving node shaft 812, which rotates integrally with the pinion gear 931.

[0132] 36 and 37, the operation of the transmission mechanism 91 will be described. The mounting portion 191 has a mounting surface 192 to which a hand 190 as an end effector is mounted by a bolt or the like. In FIG. 36, the mounting surface 192 faces downward (in the −Z-axis direction).

[0133] When the motor M3 rotates the shaft 23 in the rotation direction r7, causing the belt E3 to rotate in the direction R7 (see FIG. 14), the third hollow shaft 63 of the pitch movement unit 9 in the robot wrist 7 shown in FIG. 36 rotates the belt E22 in the direction of arrow R71. As a result, the rack gear 921 fixed to the belt clamp 808 moves in the −X1 axis direction. The linear movement of the rack gear 921 in the −X1 axis direction is converted into rotational movement in the direction of arrow r72 about the axis AX812 of the pinion gear 931.

[0134] The pinion gear 931 rotates the moving node shaft 812 in the direction of arrow r72. As a result, the rotor 912, which is provided on the moving node shaft 812 and around which the belt E33 is wound, rotates in the direction of arrow r72, and the belt E33 rotates in the direction of arrow R72. The rotation of the belt E33 causes the attachment portion 191 fixed to the tip node shaft 822 to rotate (pivot) in the direction of arrow r72 around the axis AX822 (pitch axis P). The attachment surface 192, which faced the -Z axis direction, now faces forward (+X1 axis direction), as shown in FIG.

[0135] Furthermore, when the motor M3 rotates the shaft 23 in the rotation direction r8, causing the belt E3 to rotate in the direction R8 (see FIG. 14), in the robot wrist 7 shown in FIG. 37, the third hollow shaft 63 of the pitch movement unit 9 rotates the belt E22 in the direction of the arrow R81, which is opposite to the arrow R71. As a result, the rack gear 921 fixed to the belt clamp 808 moves in the +X1 axis direction. The linear movement of the rack gear 921 in the +X1 axis direction is converted into rotational movement in the direction of the arrow r82 about the axis AX812 of the pinion gear 931.

[0136] The pinion gear 931 rotates the moving node shaft 812 in the direction of arrow r82. As a result, the rotor 912, which is provided on the moving node shaft 812 and around which the belt E33 is wound, rotates in the direction of arrow r82, and the belt E33 rotates in the direction of arrow R82, which is opposite to arrow R72. Due to the rotation of the belt E33, the mounting portion 191 fixed to the tip node shaft 822 rotates (pivots) in the direction of arrow r82 around the axis AX822 (pitch axis P). The mounting surface 192, which faced forward (+X1 axis direction), now faces downward (-Z axis direction), as shown in FIG. 36 , for example.

[0137] When the second hollow shaft 62 of the lifting / lowering operation unit 8 rotates the belt E22, the pinion gear 931 also moves integrally with the moving link shaft 812. This may change the relative position between the pinion gear 931 and the rack gear 921, causing the mounting unit 191 to rotate about the pitch axis P. In other words, a pitch movement may occur following the lifting / lowering movement. In such a case, for example, the robot control device 10 may control the motor M3 so as to maintain the relative position between the pinion gear 931 and the rack gear 921, in addition to the motor M2 for the lifting / lowering movement, thereby allowing only the lifting / lowering movement to be performed.

[0138] <Cable Storage Section> As shown in FIG. 26 , the bottom wall 811d of the casing 810 includes a first bottom wall 811d1 and a second bottom wall 811d2 connected to the first bottom wall 811d1 and protruding upward. The bottom wall 811d has a stepped shape in the Y1-axis direction. A lower cover 813 is disposed below the second bottom wall 811d2. The lower cover 813 is connected to the first bottom wall 811d1 and the side wall 811s. As shown in FIGS. 31 and 32 , the lower cover 813 and the second bottom wall 811d2 define a storage section 809. The storage section 809 is open in the extension direction of the casing 810. The bottom wall 811d and the lower cover 813 function as partition walls that separate the storage section 809 from a space in the casing 810 in which the belt E33 is stored.

[0139] In this embodiment, as described above, the multiple shaft 6 is used as the drive shaft for the belts E22 and E32. Furthermore, as shown in FIGS. 8 and 9 , the upper end of the multiple shaft 6 is connected to the cable housing 44 of the robot arm 4. As shown in FIGS. 31 and 32 , the lower end of the multiple shaft 6 is located within the wrist housing 70. Furthermore, the end of the accommodation section 809 in the −X1 axis direction is located within the wrist housing 70. Therefore, the cable housing 44 in the arm housing 40, the interior of the multiple shaft 6, and the accommodation section 809 are connected to each other. Therefore, for example, a cable can be routed from the base end 404 of the arm housing 40 through the cable housing 44, the interior of the multiple shaft 6, the lower end of the wrist housing 70, the opening of the accommodation section 809 in the −X1 axis direction, and the interior of the accommodation section 809 to the opening of the accommodation space in the +X1 axis direction.

[0140] The robot wrist 7 described above includes a wrist housing 70 having an opening 702 in its bottom wall 701d and a link mechanism 80 constituting a Scott-Russell link. The link mechanism 80 includes a first link portion 81 as a long link and a second link portion 84 as a short link. The attachment portion 191 attached to the distal link shaft 822 moves up and down in response to forward movement of the moving link shaft 812 of the first link portion 81. This allows the attachment portion 191, to which the end effector is attached, to be raised and lowered while minimizing the complexity of the configuration of the robot wrist 7. The moving link shaft 812 and the first end portion 814 are disposed within the wrist housing 70, and the base end portion 841 (shaft 843) of the second link portion 84 is disposed within the wrist housing 70 at the distal end portion 705 of the wrist housing 70. The link mechanism 80 is exposed to the outside of the wrist housing 70 through the opening 702 in response to the forward movement of the moving joint shaft 812, and is housed within the wrist housing 70 through the opening 702 in response to the rearward movement of the moving joint shaft 812. This increases the rigidity of the entire robot wrist 7. Furthermore, for example, by moving the moving joint shaft 812 rearward to shorten the vertical length of the robot wrist 7, the robot wrist 7 can be advanced into an area with a relatively narrow vertical length.

[0141] Furthermore, a belt E33 is stretched between the moving joint shaft 812 and the tip joint shaft 822 of the link mechanism 80, and the rotational power of the belt E32 is transmitted to the belt E33 by the transmission mechanism 91, thereby allowing the tip joint shaft 822 to rotate about the axis AX822 (pitch axis P). In other words, the moving joint shaft 812 and the tip joint shaft 822 are used as a drive shaft and a driven shaft for pitch movement, respectively, so that a drive shaft and a driven shaft for causing the robot wrist 7 to perform a pitch movement are not required. This prevents an increase in the number of parts of the robot wrist 7. As a result, the size of the robot wrist 7 is prevented from increasing. Furthermore, an increase in the mass of the robot wrist 7 is prevented.

[0142] The transmission mechanism 91 also includes a rack gear 921 that is fixed to the belt E32 via the belt clamp 808 and moves in the X1-axis direction, and a pinion gear 931 that is fixed to the movable joint shaft 812. Therefore, the linear movement of the rack gear 921 in the X1-axis direction caused by the rotation of the belt E32 can be converted into rotation about the axis of the movable joint shaft 812 via the pinion gear 931. This allows the belt E33 to rotate and the mounting portion 191 to rotate about the pitch axis P. Therefore, the robot wrist 7 can be made to perform lifting and pitching movements while minimizing the complexity of the configuration of the robot wrist 7.

[0143] Furthermore, a multiple shaft 6 is used as a drive shaft for the belt E22 and a drive shaft for the belt E32. Also, a single driven shaft 72 is used as a driven shaft for the belt E22 and a driven shaft for the belt E32. This prevents the configuration of the robot wrist 7 from becoming too complicated. Also, the robot wrist 7 can be made smaller.

[0144] The first link portion 81 in the link mechanism 80 of the robot wrist 7 is configured as a casing 810. This increases the rigidity of the robot wrist 7. The belt E33 is also disposed inside the casing 810. This prevents the belt E33 from interfering with other components inside the wrist housing 70 or with the belts E22 and E32.

[0145] The casing 810 further includes a housing portion 809 capable of housing a cable. The housing portion 809 is provided along the extension direction of the casing 810 and is separated from the area inside the casing 810 in which the belt E33 is disposed. Therefore, it is possible to prevent the cable housed in the housing portion 809 from interfering with the belt E33.

[0146] The wrist housing 70 also includes a front end wall 701f and a partition wall 706b located behind the front end wall 701f. The front end wall 701f is configured to be removable from the partition wall 706b. A through-hole 706h is formed in the partition wall 706b, penetrating the X1 axis direction (front-rear direction). An adjustment shaft 742 is inserted through the through-hole 706h, allowing the position of a holding member 741 that holds the driven shaft 72 to be adjusted in the X1 axis direction. Therefore, by removing the front end wall 701f and adjusting the amount of protrusion of the adjustment shaft 742 toward the holding member 741, the tension of the belts E22 and E32 can be adjusted via the driven shaft 72. Furthermore, the space defined by the front end wall 701f and the partition wall 706b can be used as a sensor housing 706.

[0147] <Other Embodiments of the Robot Wrist> Wrist housing 70 may have opening 702 in the +Z-axis direction or the −Z-axis direction. At least a portion of link mechanism 80 may be exposed to the outside through opening 702 when moving joint shaft 812 in the +X1-axis direction, and at least a portion of link mechanism 80 may be housed within wrist housing 70 through opening 702 when moving joint shaft 812 in the −X1-axis direction. For example, all of link mechanism 80 may be configured to be housed within wrist housing 70.

[0148] The attachment portion 191 of the robot wrist 7 is not limited to the hand 190 that holds the workpiece W, and may be configured to be able to attach various end effectors.

[0149] The belts E22, E32, and E33 may be any endless members, and may be timing belts or chains.

[0150] <Drive Unit and Control Mechanism> Next, the drive unit 2 that drives the robot arm 4 and the robot wrist 7 will be described. As described above, the robot 1 is capable of performing arm extension / retraction, wrist rotation, wrist lift / lowering, and wrist pitching. The arm extension / retraction operation is an operation in which the arm housing 40 extends and retracts due to the rotation of the belt 471. The wrist rotation operation is an operation in which the wrist housing 70 rotates around the axis AX61 of the first hollow shaft 61 due to the rotation of the belt E1. The wrist lift / lowering operation is an operation in which the rotation of the belt E2 rotates the second hollow shaft 62, thereby rotating the belt E22 inside the wrist housing 70 and lifting / lowering the attachment portion 191 provided at the tip of the link mechanism 80. The wrist pitch movement is an operation in which the rotation of the belt E3 rotates the third hollow shaft 63, causing the belt E32 inside the wrist housing 70 to rotate and change the relative positions of the rack gear 921 and the pinion gear 931, thereby rotating the belt E33 and causing the distal link shaft 822 to rotate about the pitch axis P (the mounting portion 191 to rotate about the pitch axis P). The movable part corresponding to the arm extension / retraction movement is, for example, the arm housing 40 or the belt 471 that extends or retracts the arm housing 40. The movable part corresponding to the wrist rotation movement is, for example, the wrist housing 70 or the first hollow shaft 61 that rotates the wrist housing 70. The movable part corresponding to the wrist lifting movement is, for example, the lifting movement unit 8 (link mechanism 80) or the second hollow shaft 62 included in the lifting movement unit 8. The movable part corresponding to the wrist pitch movement is, for example, the pitch movement unit 9 or the third hollow shaft 63 included in the pitch movement unit 9. As a means for transmitting power to each movable part, for example, a driving part 2n shown in FIG. 38 can be considered.

[0151] The drive unit 2n of the reference example includes motors M, M1, M2, and M3, a rotary encoder R, a torque limiter TL, shafts 200, 201, 202, 21n, 22n, and 23n, and a plurality of rotating bodies.

[0152] The shaft 200 is directly connected to the motor M. The power of the shaft 200 is transmitted to the shaft 202 via the shaft 201, to which the rotary encoder R and the torque limiter TL are connected. Specifically, the shaft 200 is provided with a rotating body 301 that rotates integrally with the shaft 200, and the shaft 201 is provided with rotating bodies 302 and 303 that rotate integrally with the shaft 201. The shaft 202 is also provided with rotating bodies 304 and 305 that rotate integrally with the shaft 202, and a rotating body 307 that is rotatable relative to the shaft 202. The rotation of the shaft 200 is transmitted to the rotating body 303 via the rotating body 301, the belt E01, the rotating body 302, and the shaft 201. The rotation of the rotating body 303 is transmitted to the rotating body 304 via the belt E02. This causes the shaft 202 to rotate. When the diameter of the rotor 304 is 1d, the diameter of the rotor 303 is 2d. The amount of rotation (rotation angle, rotation ratio, rotation speed) of the shaft 200 is transmitted to the shaft 202.

[0153] Shafts 21n, 22n, and 23n are directly connected to motors M1, M2, and M3, respectively. Shaft 21n is provided with a rotor 314 that is rotatable relative to shaft 21n and a rotor 312n that rotates integrally with shaft 21n. Shaft 22n is provided with a rotor 323n that rotates integrally with shaft 22n and a rotor 322 that is rotatable relative to shaft 22n. Shaft 23n is provided with a rotor 333 that is rotatable relative to shaft 23n and a rotor 331n that rotates integrally with shaft 23n. Rotators 305 and 314 support belt 471. Rotators 307 and 312n are disposed directly below rotors 305 and 314 and support belt E1. Rotators 323n and 333 support belt E2. Rotating bodies 322 and 331n are disposed directly below rotating bodies 323n and 333 and support belt E3. When the diameter of rotating body 304 is 1d, the diameters of rotating bodies 305, 314, 312n, 307, 323n, 333, 331n, and 322 that support belts 471, E1, E2, and E3 are 2d.

[0154] For example, the operation of each part when the arm housing 40 is extended will be described. When the motor M is driven and the shaft 200 rotates counterclockwise by a rotation amount of 1, the rotor 305 rotates counterclockwise by a rotation amount of 1, and the belt 471 rotates by the same rotation amount. As a result, the arm housing 40 is extended. At this time, the shafts 21n, 22n, and 23n of the drive unit 2n do not rotate. However, when the belt 471 is driven and the arm housing 40 is extended, the belt E1 for rotating the wrist directly below the belt 471 is forcibly displaced from the free end 405 of the arm housing 40 as a starting point. The displacement of the belt E1 causes the first hollow shaft 61 to rotate, resulting in the robot wrist 7 rotating.

[0155] When the arm housing 40 extends, the belt E2, which is disposed symmetrically to the belt 471 with respect to the imaginary plane AP (see FIG. 10 ), is also forcibly displaced from the free end 405 of the arm housing 40, similar to the belt E1. This causes the second hollow shaft 62 to rotate, resulting in the lifting and lowering of the robot wrist 7. Note that as the arm housing 40 extends, the belt E3 for wrist pitch operation, which is disposed directly below the belt E2 for lifting and lowering the wrist, is also forcibly displaced from the free end 405. However, because the belt E2 also displaces in the same direction as the belt E3, the relative positions of the rack gear 921 and the pinion gear 931 do not change. Therefore, the wrist pitch operation does not occur.

[0156] Thus, attempting to extend the arm housing 40 by driving only motor M poses a problem in that the robot wrist 7 rotates and moves up and down. To solve this problem by electrically controlling motors M, M1, M2, and M3, motors M1, M2, and M3, in addition to motor M, must be driven to rotate belt E1 in the same direction and by the same amount as belt 471, and belts E2 and E3 in the opposite direction and by the same amount. Column 1 (No. 1) in Figure 39 lists the rotation direction and amount of rotation of each belt required to perform the arm extension operation alone. CCW indicates counterclockwise, CW indicates clockwise, and x1, x2, etc. indicate the amount of rotation. For example, CCW x1 indicates counterclockwise rotation by 1. The numbers x1, x2, etc. indicate the ratio of the rotation amount (displacement amount) of each belt.

[0157] For example, when the motor M1 is driven to rotate the shaft 21n counterclockwise by a rotation amount of 1 to rotate the robot wrist 7 counterclockwise, the rotor 312n rotates counterclockwise by a rotation amount of 1, and the belt E1 is displaced by the rotation amount. This causes the wrist housing 70 to rotate. At this time, the shafts 200, 201, 202, 22n, and 23n of the drive unit 2n do not rotate. However, because the robot wrist 7 rotates due to the rotation of the belt E1, the relative positional relationship between the arm housing 40 and the wrist housing 70 changes. Specifically, a phase difference occurs between the central axis AX of the arm housing 40 and the central axis of the wrist housing 70 extending in the X1-axis direction. This causes the belt E21 (see FIG. 13) inside the wrist housing 70 to be displaced, causing the robot wrist 7 to move up and down. Note that, like belt E21, belt E31 in wrist housing 70 also displaces due to the phase difference, but because belts E31 and E21 displace simultaneously in the same direction, the relative positions of rack gear 921 and pinion gear 931 do not change, and therefore wrist pitch movement does not occur.

[0158] As described above, if only motor M1 is driven to rotate the robot wrist 7, there is a problem in that the robot wrist 7 is raised and lowered. To solve this problem by electrically controlling motors M, M1, M2, and M3, it is necessary to drive motors M2 and M3 in addition to motor M1 to cancel the displacement of belts E21 and E31 inside the wrist housing 70. Specifically, as shown in No. 3 and No. 4 in Figure 39, belts E2 and E3 must be rotated in the same direction and by the same amount as belt E1.

[0159] Furthermore, for example, when the motor M2 rotates counterclockwise by a rotation amount of 1 to raise the robot wrist 7 (mounting portion 191), the rotating body 323n also rotates counterclockwise by a rotation amount of 1, and the belt E2 is displaced by the same rotation amount. As a result, the belt E21 is displaced, and the wrist is raised and lowered. At this time, the shafts 200, 201, 202, 21n, and 23n of the drive unit 2n do not rotate. However, the rotation of the belt E2 displaces the belt E21 inside the wrist housing 70, and the pinion gear 931 moves together with the moving link shaft 812. This changes the relative position of the rack gear 921 and the pinion gear 931. As a result, a wrist pitch movement is performed in the robot wrist 7.

[0160] As described above, attempting to raise or lower the robot wrist 7 by driving only motor M2 results in the problem of pitch motion of the robot wrist 7. To solve this problem by electrically controlling motors M, M1, M2, and M3, it is necessary to drive motor M3 in addition to motor M2 to maintain the positional relationship between the rack gear and pinion gear inside the wrist housing 70. Specifically, as shown in Nos. 5 and 6 in Figure 39, in order to displace belt E31 in the same direction and by the same amount as belt E21, belt E3 must be rotated in the same direction and by the same amount.

[0161] When only the motor M3 for wrist pitch movement is driven, the belts 471, E1, and E2 do not move, so the wrist pitch movement can be performed independently by the motor M3 alone.

[0162] FIG. 39 shows the rotation direction and rotation amount of each belt required to independently execute each of the following operations: (No. 1) arm extension, (No. 2) arm retraction, (No. 3) wrist rotation (counterclockwise), (No. 4) wrist rotation (clockwise), (No. 5) wrist lift, (No. 6) wrist lowering, (No. 7) wrist pitch movement (r72 direction, see FIG. 37), and (No. 8) wrist pitch movement (r82 direction, see FIG. 36). When the drive unit 2n is applied to the robot 1 as described above, it is possible to independently execute each of the operations (No. 1) to (No. 8) by inputting displacement commands to the motors M, M1, M2, and M3 to drive them. However, such electrical control requires a complex algorithm. This can result in problems such as increased processing load on the robot controller 10 and the controller 101, increased power consumption, and reduced responsiveness of each moving part.

[0163] Therefore, in this embodiment, at least part of the above problem is solved by the control mechanism 20. The control mechanism 20 is a mechanical mechanism configured to independently operate the first movable part and the second movable part in a structure having multiple movable parts, including a first movable part and a second movable part that is in a driven relationship with the first movable part. Below, first, using FIGS. 40 to 43, we will explain how the second movable part operates in response to the operation of the first movable part (the driven relationship) in a structure 150n of a reference example that does not include a control mechanism. Next, we will explain how the driven relationship is canceled in a structure 150 that includes a control mechanism 20a using FIGS. 44 to 51.

[0164] 40 , the structure 150n includes a first housing 133, a second housing 147, a first motor 131, a first shaft 132n that is the output shaft of the first motor 131, a second motor 141, and a second shaft 142n that is the output shaft of the second motor 141. The first housing 133 is a first movable part that is connected to the first shaft 132n and rotates around the axis ax1 of the first shaft 132n.

[0165] A rotating body 143n fixed to the second shaft 142n and rotating around the axis ax2 of the second shaft 142n, a rotating body 144n fixed to the shaft 146 and rotating around the axis ax3 of the shaft 146, and a belt 145 wound around the rotating bodies 143n and 144n are disposed within the first housing 133. One end of the shaft 146 protrudes from the first housing 133 and is fixed to the second housing 147. The second housing 147 is a second movable part that revolves around the axis ax3 of the shaft 146. When the second shaft 142n rotates, the belt 145 rotates, and the rotating body 144n and the shaft 146 rotate together. As a result, the second housing 147 revolves around the axis ax3.

[0166] 41 to 43, the operation of the entire structure 150n when the first housing 133 is rotated will be described. Note that the dashed line 133s shown in FIG.

[0167] In the initial state shown in FIG. 41 , when the first motor 131 is driven to rotate the first shaft 132n, the first housing 133 rotates around the axis ax1. At this time, the second motor 141 is not driven, so the rotating bodies 143n and 144n do not rotate. Therefore, as the first housing 133 rotates, the relative positional relationship between the first housing 133 and the second housing 147 changes, as shown in FIG. 42 , causing the second housing 147 to rotate with respect to the first housing 133. In order to maintain the relative positional relationship between the first housing 133 and the second housing 147 in the initial state shown in FIG. 41 and rotate only the first housing 133, it is necessary to drive the second motor 141 to rotate the rotating body 144n and the shaft 146 in the same rotational direction and by the same rotational amount (rotational angle) as the first shaft 132n. For example, when the first housing 133 (first shaft 132n) rotates (turns) 30° in the direction of arrow r91 around axis ax1 shown in Fig. 41, it is necessary to drive the second motor 141 to rotate the rotor 144n and the shaft 146 30° in the direction of arrow r92 around axis ax3 shown in Fig. 42. This makes it possible to turn only the first housing 133 while maintaining the positional relationship between the first housing 133 and the second housing 147 in the initial state, as shown in Fig. 43.

[0168] As described above, in the comparative example structure 150n, in order to rotate only the first housing 133, it is necessary to drive the second motor 141 in addition to the first motor 131.

[0169] 44 is a schematic diagram showing a structure 150 having a control mechanism 20. The control mechanism 20 includes a correction unit 17 made up of a differential gear 160 and a speed reducer 170. First, the differential gear 160 will be described with reference to FIGS.

[0170] Figure 45 shows an example of a differential device 160. The differential device 160 shown in Figure 45 is a ball differential. The differential device 160 has a first differential shaft 161 and a second differential shaft 162 that extend in a predetermined direction, and a rotor 163. In Figure 45, the predetermined direction is shown as the Z-axis direction. An axis ax4 of the first differential shaft 161 and the second differential shaft 162 extends in the Z-axis direction.

[0171] The rotating body 163 has a plurality of housing portions 164 in which steel balls (hereinafter referred to as balls 165) are housed. The rotating body 163 and the balls 165 are collectively referred to simply as the rotating body or the retainer pulley. The first differential shaft 161 has a flange 161f to which a slide plate 161p is attached. The flange 161f abuts against the balls 165 via the slide plate 161p in the +Z axis direction. The first differential shaft 161 rotates integrally with the slide plate 161p and the flange 161f. The second differential shaft 162 has a flange 162f to which a slide plate 162p is attached. The flange 162f abuts against the balls 165 via the slide plate 162p in the -Z axis direction. The second differential shaft 162 rotates integrally with the slide plate 162p and the flange 162f. The first differential shaft 161 and the second differential shaft 162 are supported by a shaft member 166 so as to be rotatable about an axis ax4.

[0172] The operation of the differential gear 160 will be described using Figures 46 to 49. Figure 46 shows a ball 165 with a diameter D and a first differential shaft 161 and a second differential shaft 162 that sandwich the ball 165. Note that in the figures and explanations following Figure 46, the slide plates 161p and 162p are omitted as appropriate. In the example shown in Figure 46, the rotating body 163 is in a fixed state. The upper part of Figure 46 shows the differential gear 160 in an initial state, and the lower part of Figure 46 shows the differential gear 160 in a state in which the first differential shaft 161 has rotated from the initial state. The fixed state is a state in which the target shaft or rotating body is stopped. The fixed state is a state in which the target shaft or rotating body does not displace even when an external force is applied to the target shaft or rotating body. For example, when a motor operably connected to a shaft or a motor operably connected to a rotating body is servo-on and exhibiting a servo lock function, the shaft or rotating body is in a fixed state.

[0173] When the first differential shaft 161 rotates from the initial state shown in FIG. 46 , the balls 165 in contact with the first differential shaft 161 rotate. When the movement amount (rotation amount) of the first differential shaft 161 is Dθ, the rotation angle of the balls 165 in contact with the first differential shaft 161 is θ. Because the rotor 163 is fixed, the second differential shaft 162 in contact with the balls 165 moves by the movement amount Dθ in the opposite direction to the first differential shaft 161 due to the rotation of the balls 165. As a result, as shown in FIG. 47 , when power is input to the first differential shaft 161 and the first differential shaft 161 rotates around the axis ax4 by the rotation amount (angular velocity) ω, the second differential shaft 162 rotates by the rotation amount ω in the opposite direction to the first differential shaft 161. Similarly, when rotational power is input to the second differential shaft 162 and the second differential shaft 162 rotates around the axis ax4 by an amount of rotation ω, the first differential shaft 161 rotates by an amount of rotation ω in the opposite direction to the second differential shaft 162.

[0174] Next, a case where one of the first differential shaft 161 and the second differential shaft 162 is fixed will be described using FIG. 48 . The upper part of FIG. 48 shows the differential gear 160 in an initial state when the second differential shaft 162 is fixed, and the lower part of FIG. 48 shows the differential gear 160 in a state where the balls 165 have rotated from the initial state. As shown in FIG. 48 , when the second differential shaft 162 is fixed and the first differential shaft 161 and the rotor 163 are not fixed, if the balls 165 rotate on the second differential shaft 162 by a rotation angle θ, the balls 165 move on the second differential shaft 162 by a movement amount Dθ. At this time, the first differential shaft 161, which is in contact with the balls 165, further moves by a movement amount Dθ due to the rotation of the balls 165. Therefore, the total movement amount of the first differential shaft 161 from the initial position is 2Dθ. In other words, the rotation amount of the first differential shaft 161 is twice as large as the rotation amount of the rotor 163 having the balls 165. In other words, the rotation amount of the rotor 163 is half that of the first differential shaft 161.

[0175] Although not shown in the figures, similarly, when the first differential shaft 161 is fixed and the second differential shaft 162 and the rotor 163 are not fixed, when the balls 165 rotate on the first differential shaft 161 by a rotation angle θ, the total amount of movement of the second differential shaft 162 from the initial position is 2Dθ. In other words, the amount of rotation of the second differential shaft 162 is twice the amount of rotation of the rotor 163 that has the balls 165. It can also be said that the amount of rotation of the rotor 163 is half that of the second differential shaft 162.

[0176] 49 , when the second differential shaft 162 is in a fixed state, if rotational power is input to the first differential shaft 161 and the first differential shaft 161 rotates about the axis ax4 by an amount of rotation of 2ω, the rotating body 163 rotates by an amount of rotation ω in the same rotational direction as the first differential shaft 161. Furthermore, when rotational power is input to the rotating body 163 and the rotating body 163 rotates about the axis ax4 by an amount of rotation ω, the first differential shaft 161 rotates by an amount of rotation 2ω in the same direction as the rotating body 163. Although not shown in the figure, when the first differential shaft 161 is in a fixed state, if rotational power is input to the second differential shaft 162 and the second differential shaft 162 rotates about the axis ax4 by an amount of rotation 2ω, the rotating body 163 rotates by an amount of rotation ω in the same rotational direction as the second differential shaft 162. Furthermore, when the first differential shaft 161 is in a fixed state, if rotational power is input to the rotating body 163 and the rotating body 163 rotates around the axis ax4 by a rotational amount ω, the second differential shaft 162 rotates in the same direction as the rotating body 163 by a rotational amount 2ω.

[0177] Returning to FIG. 44 , the structure 150 will be described. In the structure 150, the first shaft 132, through which the power of the first motor 131 is output, and the second shaft 142, through which the power of the second motor 141 is output, are each formed integrally with a flange. The first motor 131 and the second motor 141 are servo motors having a servo lock function. A rotor 163 serving as a retainer pulley incorporated into a ball differential is disposed between the first shaft 132 and the second shaft 142. The first shaft 132, the second shaft 142, and the rotor 163 constitute a differential device 160. The first shaft 132 functions as the first differential shaft of the differential device 160 and as a first drive shaft that outputs power for turning the first housing 133. The second shaft 142 functions as the second differential shaft of the differential device 160 and as a second drive shaft that outputs power for turning the second housing 147.

[0178] Belt 145 is stretched over rotating body 163 and rotating body 144. The diameter of rotating body 144 is half the diameter of rotating body 139. Therefore, the rotation speed of rotating body 144 is twice the rotation speed of rotating body 163. Rotating bodies 163, 144, and belt 145 constitute a speed reducer (speed converter) 170. The other configuration of structure 150 is similar to that of structure 150n of the comparative example.

[0179] The differential gear 160 and the speed reducer 170 are provided at a connecting portion CP, which is a power transmission path between the first shaft 132 and the second shaft 142. The connecting portion CP is a portion that operably connects the first shaft 132 and the second shaft 142. The differential gear 160 and the speed reducer 170 are also referred to as a correction portion 17. The correction portion 17 corrects the movement (driven relationship) of the second housing 147 resulting from the movement of the first housing 133. The first shaft 132, the second shaft 142, the differential gear 160, and the correction portion 17 constitute a control mechanism 20a.

[0180] 50 and 51 , the operation of the entire structure 150 when the first housing 133 is rotated will be described. To rotate the first housing 133 30° around the axis ax1 from the initial state shown in FIG. 50 , first, the first motor 131 is driven to rotate the first shaft 132 (see FIG. 44 ) 30°, for example, in the direction of arrow r9 shown in FIG. 50 . Driving the motor means that the control device 101 or the robot control device 10 inputs a displacement command to the motor. At this time, the second motor 141 is servo-on, i.e., is under power supply control, and is performing a servo lock function. Therefore, the second shaft 142 is in a fixed state.

[0181] When the first shaft 132 is rotated with the second shaft 142 fixed, the rotor 163 of the differential device 160 rotates half the rotation amount of the first shaft 132, that is, 15°. Furthermore, because the diameter of the rotor 144 is half the diameter of the rotor 139, the rotation angle of the rotor 144 is twice the rotation angle of the rotor 139. Therefore, the rotor 144 rotates 30°. As a result, as shown in FIG. 51 , the first housing 133 is rotated 30°, and the relative positional relationship between the first housing 133 and the second housing 147 can be maintained at the initial positional relationship shown in FIG. 50 . Note that, with the first shaft 132 fixed, the second motor 141 can be driven to rotate the second shaft 142 by a desired rotation amount, thereby rotating only the second housing 147 around the axis ax3.

[0182] As described above, by applying the control mechanism 20a to the structure 150, the first housing 133 can be rotated around the axis ax1 by only the power of the first motor 131 while maintaining its relative positional relationship with the second housing 147. Furthermore, the second housing 147 can be rotated around the axis ax3 by only the power of the second motor 141 while maintaining its relative positional relationship with the first housing 133. Therefore, by applying the control mechanism 20a to a structure having multiple movable parts that are driven by one another, each movable part can be independently operated by a mechanical mechanism without relying on electrical control to control the displacement of the multiple motors. Therefore, in a structure with multiple degrees of freedom, each degree of freedom can be independently operated while avoiding an increase in the processing load on the control device that controls the structure, an increase in power consumption, and a decrease in the responsiveness of each movable part.

[0183] Next, the control mechanism 20 applied to the robot arm 4 and the robot wrist 7 will be described. FIG. 52 schematically shows the power transmission paths from the drive unit 2 provided at the base end 404 of the robot arm 4 to each movable unit. FIG. 52 shows the drive pulley and the retainer pulley incorporated into the differential gear, among the multiple rotating bodies of the drive unit 2 shown in FIG. 20. In FIG. 52 and subsequent figures, the driven pulleys among the rotating bodies are omitted. First, the configuration of the drive unit 2 of this embodiment will be specifically described using FIG. 20 and FIG. 52. The drive unit 2 includes a rotary encoder R, a torque limiter TL, a motor M for extending and retracting the arm, a motor M1 for rotating the wrist, a motor M2 for raising and lowering the wrist, a motor M3 for pitching the wrist, shafts 200, 201, 202, 21, 22, and 23, and multiple rotating bodies.

[0184] As shown in Fig. 20, rotors 304, 305, 306, and 307 are provided on shaft 202 in this order toward the -Z axis direction, that is, from top to bottom. Rotators 304, 305, and 307 rotate integrally with shaft 202. Rotator 307 is freely rotatable relative to shaft 202. Rotator 307 is omitted from Fig. 52. Rotator 304 has a diameter of 1d, and rotors 304, 305, and 307 have a diameter of 2d.

[0185] As shown in FIG. 20 , rotors 315, 314, 313, 312, and 311 are provided on shaft 21 in this order from top to bottom. Rotor 312 is a retainer pulley. As shown in FIG. 52 , shaft 21 includes shaft 212 arranged above rotor 312 and shaft 211 arranged below rotor 312. Although not shown in FIG. 20 , shafts 212 and 211 each have a flange that abuts against the steel ball of rotor 312 via a plate. This also applies to the shafts 22 and 23 arranged above and below the retainer pulley. Shaft 212, rotor 312, and shaft 211 form a first differential device 160a. Rotors 315, 314, and 313 are provided on shaft 212. Rotating bodies 315 and 313 rotate integrally with shaft 212, and rotating body 314 is rotatable relative to shaft 211. Rotating body 314 is omitted from Fig. 52. Rotating body 311 is provided on shaft 211 and rotates integrally with shaft 211. The diameters of rotating bodies 313 and 311 are 1d, and the diameters of rotating bodies 312 and 314 are 2d. Rotating body 315 is a spur gear and meshes with a spur gear (rotating body 324) provided on shaft 212.

[0186] As shown in FIG. 20 , rotors 324, 323, 322, and 321 are provided on shaft 22 in this order from top to bottom. Rotor 323 and rotor 321 are retainer pulleys. As shown in FIG. 52 , shaft 22 includes shaft 223, shaft 222, and shaft 221. Shaft 223 is disposed above rotor 323, and shaft 222 is disposed between rotors 323 and 321. Shaft 221 is disposed below rotor 321. Shaft 223, rotor 323, and shaft 222 form second differential 160b. Shaft 222, shaft 221, and rotor 321 form third differential 160c. In other words, shaft 222 is a differential shaft shared by both second differential 160b and third differential 160c.

[0187] Rotating body 322 is provided on shaft 222 and is rotatable relative to shaft 222. Rotating body 322 is omitted in Fig. 52. Rotating bodies 323, 322, and 321 have a diameter of 2d. Rotating body 324 is a spur gear that is provided on shaft 223 and rotates integrally with shaft 223.

[0188] As shown in FIG. 20 , rotors 333, 332, and 331 are provided on shaft 23 in this order from top to bottom. Rotor 331 is a retainer pulley. As shown in FIG. 52 , shaft 23 includes shaft 232 arranged above rotor 331 and shaft 231 arranged below rotor 331. Shaft 232, rotor 331, and shaft 231 form a fourth differential device 160d. Rotors 333 and 332 are provided on shaft 232. Rotor 333 is rotatable relative to shaft 232. Rotor 333 is omitted from FIG. 52 . Rotor 332 rotates integrally with shaft 232. Rotors 333 and 331 have a diameter of 2d, and rotor 332 has a diameter of 1d.

[0189] 20 , shaft 202 and shaft 212 support belt 471 and belt E1. Specifically, belt 471 is supported by rotating bodies 305 and 314. Belt E1 is supported below belt 471 by rotating bodies 307 and 312. Belt E03 is stretched between belt 471 and belt E1 in the Z-axis direction, between rotating bodies 306 and 313.

[0190] As shown in FIG. 20 , shaft 22 (shaft 223) and shaft 23 (shaft 232) support belts E2 and E3. Specifically, as shown in FIG. 20 , belt E2 is supported by rotating bodies 323 and 333. Belt E3 is supported below belt E2 by rotating bodies 322 and 331. Belt E05 is stretched between belts E2 and E3 in the Z-axis direction, between rotating bodies 323 and 332. Note that belt E04 is stretched between rotating body 311 provided on shaft 21 and rotating body 321 provided on shaft 22.

[0191] Belt E03 in drive unit 2 is wound around rotating bodies 306 and 313, which have different diameters. As shown in Figure 52, rotating bodies 306, 313, and belt E03 constitute a first reduction gear unit 171. First reduction gear unit 171 connects shaft 202, which transmits the power of motor M to belt 471, to shaft 21, which transmits the power of motor M1 to belt E1. First reduction gear unit 171 also connects shaft 202, which transmits the power of motor M2 to belt E2, to shaft 22, which transmits the power of motor M2 to belt E2, via spur gears 315 and 324.

[0192] Belt E04 is stretched over rotating bodies 311 and 321, which have different diameters. Rotating bodies 311, 321, and belt E04 constitute second reduction gear unit 172. Second reduction gear unit 172 connects shaft 211, which transmits the power of motor M1 to belt E1, and shaft 22, which transmits the power of motor M2 to belt E2.

[0193] Belt E05 is stretched over rotating bodies 323 and 332, which have different diameters. Rotating bodies 323, 332, and belt E05 constitute a third reduction gear unit 173. Third reduction gear unit 173 connects shaft 222, which transmits the power of motor M2 to belt E2, and shaft 231, which transmits the power of motor M3 to belt E3.

[0194] The first reduction gear unit 171 and the first differential gear 160a are provided on a power transmission path between the shaft 202 and the shaft 21. The first reduction gear unit 171 and the first differential gear 160a constitute a first correction unit A1. The first correction unit A1 converts the power (amount of rotation) output from the motor M to the shaft 202 using the first reduction gear unit 171 and inputs the converted power to the first differential gear 160a, thereby rotating (displacing) the belt E1. This corrects the rotation of the belt E1 due to the expansion and contraction of the arm housing 40.

[0195] Furthermore, the first reduction gear unit 171 and the second differential gear 160b constitute a second correction unit A2. The second correction unit A2 is provided on a power transmission path between the shaft 202 and the shaft 22. The second correction unit A2 converts the power output from the motor M to the shaft 202 by the first reduction gear unit 171 and inputs it to the second differential gear 160b to rotate the belt E2. This corrects the rotation of the belt E2 due to the expansion and contraction of the arm housing 40.

[0196] The second reduction gear unit 172 and the third differential gear 160c are provided on a power transmission path between the shaft 21 and the shaft 22. The second reduction gear unit 172 and the third differential gear 160c constitute a third correction unit A3. The third correction unit A3 converts the power output from the motor M1 to the shaft 21 using the second reduction gear unit 172 and inputs it to the third differential gear 160c, causing the belt E2 to rotate. This corrects the rotation of the belt E22 caused by the rotation of the wrist housing 70.

[0197] The third reduction gear unit 173 and the fourth differential gear 160d are provided on a power transmission path between the shafts 22 and 23. The third reduction gear unit 173 and the fourth differential gear 160d constitute a fourth correction unit A4. The fourth correction unit A4 converts the power output from the motor M2 to the shafts 221 and 222 and the power output from the motors M and M1 to the shaft 223 using the third reduction gear unit 173 and inputs it to the fourth differential gear 160d to rotate the belt E3. This corrects the rotation of the belt E33 due to the wrist lifting operation via the belt E32.

[0198] 53 to 56 will be used to specifically describe how the movable parts corresponding to the motors M, M1, M2, and M3 are independently driven to operate independently. The movable parts corresponding to the motor M for extending and retracting the arm are the arm housing 40 and the belt 471 that extends and retracts the arm housing 40. The movable parts corresponding to the motor M1 for rotating the wrist are the wrist housing 70 and the first hollow shaft 61 that rotates the wrist housing 70. The movable parts corresponding to the motor M2 for lifting and lowering the wrist are the lifting operation unit 8 (link mechanism 80) and the second hollow shaft 62 included in the lifting operation unit 8. The movable parts corresponding to the motor M3 for pitching the wrist are the pitch operation unit 9 and the third hollow shaft 63 included in the pitch operation unit 9. In FIGS. 53 to 56, the rotation direction (CCW, CW) of each part (member) is indicated by an arrow, and the amount of rotation (×1, ×2, etc.) is superimposed on each part. The power transmission paths from the motors M, M1, M2, and M3 are indicated by dashed arrows. In the diagram, a motor marked with a slash ( / ) indicates that it is in a servo-locked state, and each part marked with a slash indicates that it is in a fixed state.

[0199] Figure 53 shows the power transmission path from motor M to each component when extending the arm housing 40. When the robot system 100 is started, the robot controller 10 sets the motors M, M1, M2, and M3 to the servo-on state. When a command to extend the arm housing 40 is input from the controller 101 to the robot controller 10, the robot controller 10 inputs a displacement amount corresponding to the extension command to motor M to drive motor M. Motors M1, M2, and M3 and the shafts and rotating bodies driven by them are fixed. Note that when the arm extension operation is performed independently, each belt must be displaced, as shown in column No. 1 of Figure 39.

[0200] When motor M is driven and shaft 200 rotates counterclockwise by an amount of 1 (CCW x 1), the rotational power of shaft 200 is transmitted to rotor 304 via rotor 301, belt E01, rotor 302, shaft 201, rotor 303, and belt E02. Rotator 304 and shaft 202 rotate counterclockwise by an amount of 1 (CCW x 1). As a result, rotor 305 rotates counterclockwise integrally with shaft 202 by an amount of 1 (CCW x 1), and belt 471 is displaced counterclockwise by an amount of 1 (CCW x 1).

[0201] Furthermore, the rotating body 306 rotates integrally with the shaft 202 (CCW×1), and power is transmitted to the rotating body 313 via the belt E03, causing the rotating body 313 to rotate integrally with the shaft 212. Due to the difference in diameter between the rotating body 306 and the rotating body 313 that constitute the first reduction gear unit 171, the rotating body 313 and the shaft 212 rotate counterclockwise by an amount of rotation of 2 (CCW×2).

[0202] The rotation (CCW x 2) of the shaft 212 is input to the rotor 312, which is a retainer pulley. Because the shaft 211 constituting the first differential gear 160a is fixed, the input from the shaft 212 causes the rotor 312 to rotate counterclockwise by an amount of rotation of 1 (CCW x 1). As a result, power of the amount of rotation of 1 is transmitted counterclockwise to the belt E1 (CCW x 1). As a result, the displacement of the belt E1 due to the elongation of the belt 471 is canceled (see No. 1 in Figure 39), and the belt E1 for lifting the wrist does not rotate. In other words, the displacement of the belt E1 is canceled by the first correction unit A1, which includes the first reduction gear unit 171 and the first differential gear 160a.

[0203] The rotation of shaft 212 (CCW×2) is also transmitted to shaft 223 via spur gears 315 and 324. The rotation direction of shaft 212 is converted by spur gears 315 and 324, causing shaft 223 to rotate clockwise by an amount of 2 (CW×2). Because shaft 222 constituting second differential device 160b is fixed, rotating body 323 rotates clockwise by an amount of 1 (CW×1). As a result, power of an amount of 1 rotation is transmitted clockwise to belt E2 (CW×1). Therefore, the displacement of belt E2 due to the elongation of belt 471 (arm housing 40) is canceled (see No. 1 in FIG. 39 ). In other words, belt E2 for lifting and lowering the wrist does not displace. As a result, the displacement of belt E2 due to the elongation of belt 471 is canceled, and belt E2 for pitching the wrist does not displace. In other words, the displacement of the belt E2 when the belt 471 is driven is cancelled by the second correction unit A2 including the first reduction gear unit 171 and the second differential device 160b.

[0204] Furthermore, the clockwise rotation of the rotor 323 by an amount of 1 (CW×1) is transmitted to the rotor 332 via the belt E05, causing the rotor 332 to rotate integrally with the shaft 232. Due to the difference in diameter between the rotor 323 and the rotor 332 that constitute the third reduction gear unit 173, the rotor 332 and the shaft 232 rotate by an amount of 2 (CW×2) in the clockwise direction. The rotation of the shaft 232 is input to the rotor 331, which is a retainer pulley. Due to the input from the shaft 232 that constitutes the fourth differential device 160d, the rotor 331 rotates by an amount of 1 (CW×1) in the clockwise direction. As a result, power of an amount of 1 (CW×1) in the clockwise direction is transmitted to the belt E3. As a result, the displacement of the belt E3 due to the elongation of the belt 471 is canceled, and the belt E3 for wrist pitch operation does not displace. That is, the displacement of the belt E3 when the belt 471 is driven is cancelled by the fourth correction unit A4 including the third reduction unit 173 and the fourth differential device 160d.

[0205] As described above, when only motor M is driven to displace arm extension / retraction belt 471 (CCW x 1) to extend arm housing 40, the displacement of belt E1 due to extension of arm housing 40 can be canceled using first correction unit A1. Furthermore, the displacement of belt E2 due to extension of arm housing 40 can be canceled using second correction unit A2. Furthermore, the relative positions of rack gear 921 and pinion gear 931 can be maintained by displacing belt E3 in the same direction and by the same amount as belt E2 using fourth correction unit A4. As a result, the arm extension operation can be performed independently by motor M alone. Furthermore, for arm retraction operation, by rotating shaft 200 clockwise by an amount of rotation 1 by motor M alone, the arm retraction operation can be performed independently by motor M alone.

[0206] Figure 54 shows the power transmission paths from motor M1 to each component when rotating wrist housing 70. For example, when a command to rotate wrist housing 70 counterclockwise is input from control device 101 to robot control device 10, robot control device 10 inputs a displacement amount corresponding to the rotation command to motor M1 to drive motor M1. Note that motors M, M2, and M3 and the shafts and rotating bodies driven by them are fixed. To perform a counterclockwise wrist rotation operation alone, each belt must be displaced, as shown in column No. 3 of Figure 39.

[0207] When motor M1 is driven and shaft 211 rotates counterclockwise by an amount of 2 (CCW x 2), shaft 212 constituting first differential device 160a is fixed, so input from shaft 211 causes rotating body 312 to rotate counterclockwise by an amount of 1 (CCW x 1). As a result, belt E1 is displaced counterclockwise by an amount of 1 (CCW x 1). As a result, wrist housing 70 revolves counterclockwise around axis AX61 of first hollow shaft 61 by an amount of 1.

[0208] Furthermore, the rotation (CCW x 2) of rotor 311, which rotates integrally with shaft 211, is transmitted via belt E04 to rotor 321, which is a retainer pulley. Due to the difference in diameter between rotor 311 and rotor 321, which constitute second reduction gear unit 172, rotor 321 rotates counterclockwise by an amount of rotation of 1 (CCW x 1). Because shaft 221, which constitutes third differential gear 160c, is fixed, the rotation of rotor 321 causes shaft 222 to rotate counterclockwise by an amount of rotation of 2 (CCW x 2). Furthermore, because shaft 223, which constitutes second differential gear 160b, is fixed, the rotation of shaft 222 (CCW x 2) causes rotor 323 to rotate counterclockwise by an amount of rotation of 1 (CCW x 1). As a result, power of 1 rotation in the counterclockwise direction is transmitted to belt E2 (CCW x 1). Therefore, the displacement of the belt E22 inside the wrist housing 70 caused by the rotation of the robot wrist 7 is canceled. That is, the displacement of the belt E22 is canceled by the third correction unit A3 including the second reduction gear unit 172 and the third differential device 160c.

[0209] Furthermore, the rotation of rotor 323 (CCW×1) is transmitted to rotor 332 and shaft 232 via belt E05. Due to the difference in diameter between rotor 323 and rotor 332 constituting third reduction gear unit 173, rotor 323 and shaft 232 rotate counterclockwise by an amount of rotation of 2 (CCW×2). Because shaft 231 constituting fourth differential device 160d is fixed, rotation of shaft 232 causes rotor 331 to rotate counterclockwise by an amount of rotation of 1 (CCW×1). As a result, power of 1 rotation in the counterclockwise direction is transmitted to belt E3 (CCW×1). In other words, the displacement of belt E32 is corrected by fourth correction unit A4, which includes third reduction gear unit 173 and fourth differential device 160d.

[0210] As described above, when only motor M1 is driven to displace belt E1 for wrist rotation (CCW x 1) to rotate wrist housing 70, the displacement of belt E21 due to the rotation of wrist housing 70 can be canceled by displacing belt E2 (CCW x 1) using third correction unit A3. Furthermore, the relative positions of rack gear 821 and pinion gear 931 can be maintained by displacing belt E3 (CCW x 1) in the same direction and by the same amount as belt E2 using fourth correction unit A4. As a result, the wrist raising operation can be performed independently by motor M1 alone. Furthermore, the wrist lowering operation can be performed independently by motor M1 alone by rotating shaft 200 clockwise by an amount of 1 rotation using motor M1.

[0211] Figure 55 shows the power transmission paths from motor M2 to each component when lifting the mounting portion 191 of the robot wrist 7. For example, when a command to lift the wrist housing 70 is input from the control device 101 to the robot control device 10, the robot control device 10 inputs a displacement amount corresponding to the lift command to motor M2 to drive motor M2. Note that motors M, M1, and M3 and the shafts and rotating bodies driven by them are fixed. Note that when the wrist lifting operation is performed independently, each belt must be displaced, as shown in column No. 5 of Figure 39.

[0212] When motor M2 is driven and shaft 221 rotates clockwise by an amount of 2 (CW×2), because rotor 321 of third differential device 160c is fixed, input from shaft 221 causes shaft 222 to rotate counterclockwise by an amount of 2 (CCW×2). Because shaft 223 of second differential device 160b is fixed, rotation of shaft 222 causes rotor 323 to rotate counterclockwise by an amount of 1 (CCW×1). As a result, belt E2 is displaced counterclockwise by an amount of 1 (CCW×1). As a result, belt E22 is displaced in the direction of arrow R61 shown in FIG. 34 .

[0213] Furthermore, the rotation (CCW×1) of the rotor 323 constituting the second differential gear 160b is transmitted to the rotor 332 and the shaft 232 via the belt E05. Due to the difference in diameter between the rotor 323 and the rotor 332 constituting the third reduction gear unit 173, the rotor 332 and the shaft 232 rotate counterclockwise by an amount of rotation of 2 (CCW×2). Because the shaft 231 constituting the fourth differential gear 160d is fixed, the rotation of the shaft 232 causes the rotor 331 to rotate counterclockwise by an amount of rotation of 1 (CCW×1). As a result, the belt E3 is displaced counterclockwise by an amount of rotation of 1 (CCW×1). In other words, the displacement of the belt E32 is corrected by the fourth correction unit A4, which includes the third reduction gear unit 173 and the fourth differential gear 160d.

[0214] As described above, when only motor M2 is driven to displace belt E2 for lifting the wrist (CCW x 1), the fourth correction unit A4 is used to displace belt E3 in the same direction and by the same amount (CCW x 1) as belt E2, thereby maintaining the relative positions of rack gear 821 and pinion gear 931. As a result, the wrist lifting operation can be performed independently by motor M2 alone. Furthermore, by rotating shaft 221 clockwise by an amount of rotation of 2 by motor M2, the wrist lowering operation can be performed independently by motor M2 alone.

[0215] 56 shows the power transmission paths from motor M3 to each part when pitching the mounting part 191 of the robot wrist 7. For example, when a wrist pitch movement command is input from the control device 101 to the robot control device 10, the robot control device 10 inputs a displacement amount corresponding to the pitch movement command to motor M3 to drive motor M3. Note that motors M, M1, and M2 and the shafts and rotating bodies driven by them are in a fixed state.

[0216] When motor M3 is driven and shaft 231 rotates clockwise by an amount of 2 (CW×2), shaft 232 constituting fourth differential device 160d is fixed, so input from shaft 231 causes rotor 331 to rotate counterclockwise by an amount of 1 (CCW×1). As a result, belt E3 is displaced counterclockwise by an amount of 1 (CCW×1). As a result, belt E32 is driven via belt E31, and wrist pitch movement is performed.

[0217] As described above, the wrist pitch motion that rotates the hand 190 in the rotation direction r72 about the axis P can be performed solely by the motor M3. Furthermore, by rotating the shaft 231 clockwise by an amount of rotation of 2 by the motor M3, the wrist pitch motion that rotates the hand 190 in the rotation direction r82 about the axis P can be performed solely.

[0218] As described above, the drive unit 2 includes the control mechanism 20, which allows each moving part corresponding to the motors M, M1, M2, and M3 to operate independently. Therefore, compared to a configuration in which each moving part is operated independently by electrically controlling the motors M, M1, M2, and M3, an increase in the processing load on the robot control device 10 and the control device 101 can be suppressed. Furthermore, by driving only the motor corresponding to each moving part, the moving part can be operated independently, thereby suppressing the power consumption of the motors M, M1, M2, and M3. Furthermore, since a complex algorithm for operating each moving part independently is not required, the responsiveness of each moving part can be improved.

[0219] Furthermore, because the differential devices 160, 160a, 160b, 160c, and 160d are ball differentials, it is possible to prevent the configuration of the control mechanisms 20a and 20 from becoming complicated. Therefore, the drive unit 2 including the control mechanism 20 can be disposed at the base end 404 of the robot arm 4.

[0220] <Other Embodiments of Control Mechanism> The differential devices provided in the correction units 17, A1, A2, A3, and A4 of the control mechanisms 20 and 20a may be differential devices such as differential gears or planetary gears instead of ball differentials.

[0221] In the above embodiment, the shafts 132, 142, 202, 21, 22, and 23 serving as drive shafts are driven by the motors 131, 141, M, M1, M2, and M3, but these shafts 132, 142, 202, 21, 22, and 23 are not limited to being driven by motors, and may be driven by external forces.

[0222] In the above embodiment, the shafts and rotating bodies in the differential device were fixed using a servo lock mechanism of the servo motor, but the shafts and rotating bodies may also be fixed by other external forces other than the servo lock function.

[0223] <Correspondence> The correspondence between each component (feature) of the above embodiment and each component (feature) of the present disclosure or invention is shown below. However, each component of the embodiment is merely an example and does not limit each component of the present disclosure or invention.

[0224] The robot arm 4 is an example of a "robot arm." The X-axis direction is an example of a "first direction." The Y-axis direction is an example of a "third direction." The Z-axis direction is an example of a "second direction." The tip housing 41 and the base housing 43 are examples of a "tip housing" and a "base housing," respectively. The tip housing 41, the intermediate housing 42, and the base housing 43 are examples of "multiple housings." The arm housing 40 is an example of an "arm housing." The free end 405 is an example of a "free end of a tip housing." The base end 404 is an example of a "base end of an arm housing." The telescopic mechanism 47 is an example of an "telescopic mechanism." The belt 471 is an example of a "first belt." The shafts 481f, 481b, 481c, 482f, 482b, 482c, 483f, 202, and 21 are examples of a "first shaft." The support portion 48 is an example of a "first support portion." The belt clamp 472 is an example of a "belt clamp." The drive unit 473, the shaft 202, and the motor M are an example of a "first drive unit." The operating mechanism 50, the first mechanism 51, the second mechanism 52, and the third mechanism 53 are each an example of "at least one operating mechanism." The belts E1, E2, and E3 are an example of a "second belt." The shafts 481f, 481b, 481c, 511, 482b, 482c, 512, 202, and 21 included in the support unit 510 of the first mechanism 51 are an example of a "second shaft." The shafts 481f, 481b, 481c, 482f, 482b, 482c, 483f, 22, and 23 included in the support unit 520 of the second mechanism 52 are an example of a "second shaft." The shafts 481f, 481b, 481c, 511, 482b, 482c, 512, 22, and 23 included in the third mechanism 53 are an example of a "second shaft." The support units 510, 520, and 530 are an example of a "second support unit." The drive units 516, 526, and 536 are an example of a "second drive unit." The carriages 451 and 452, the rails 454 and 455, and the guide unit 45 are an example of a "guide unit." The first area Ar1 and the second area Ar2 are an example of a "first area" and a "second area," respectively. The motor M is an example of a "first motor." The motors M1, M2, and M3 are an example of a "second motor."The multiple shaft 6 is an example of a "multiple shaft." The first hollow shaft 61, the second hollow shaft 62, and the third hollow shaft 63 are examples of "multiple hollow shafts." The first portion 601 and the second portion 602 are examples of a "first portion" and a "second portion," respectively. The belt E11, the rotating body 611, the belt E21, the rotating body 621, the belt E31, and the rotating body 631 are examples of a "transmission unit." The second mechanism 52 is an example of a "second mechanism." The belt E2 is an example of a "second belt in the second mechanism." The central axis AX and the imaginary plane AP are examples of a "central axis" and a "imaginary plane." The first mechanism 51 is an example of a "first mechanism." The belt E1 is an example of a "second belt included in the first mechanism." The third mechanism 53 is an example of a "third mechanism." The belt E3 is an example of a "second belt included in the third mechanism." Shafts 481f, 481b, 481c, 482b, 482c, 202, 21 are "at least a part of the first support portion." Shafts 481f, 481b, 481c, 482b, 482c, 22, 23 are "at least a part of the second support portion of the second mechanism." Adjustment portion 54 is an example of an "adjustment portion." Front end portions 42f and 43f are examples of "tip portions of at least one housing." Retaining portion 541 is an example of a "retaining portion." Shaft 483f is an example of a "first shaft." Shaft 511 is an example of a "second shaft." Front end wall 545 is an example of a "tip wall." Through hole 546 and hole 544 are examples of a "hole portion." Adjustment shaft 548 is an example of an "adjustment shaft." The cable housing 44, the tip accommodating portion 441, the intermediate accommodating portion 442, the base accommodating portion 443, and the upper walls 401, 402, and 403 are an example of a "cable housing." The third region Ar3 is an example of a "third region." The rear end portion 41b is an example of a "base end portion of the tip housing." The front end portion 43f is an example of a "tip portion of the base housing." The intermediate housing 42 is an example of an "intermediate housing." The front end portion 42f and the rear end portion 42b are examples of a "tip portion and base end portion of the intermediate housing."

[0225] The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following aspects. The technical features in the above embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0226] <1> According to a first aspect of the present disclosure, there is provided a robot arm. The robot arm includes a telescopic arm housing, an extension / retraction mechanism, at least one movement mechanism, and a guide unit. The arm housing extends in a first direction. The arm housing includes a plurality of housings, including a tip housing and a base housing capable of accommodating the tip housing. The extension / retraction mechanism is configured to extend and retract the arm housing in the first direction. The extension / retraction mechanism includes a first belt accommodated in the arm housing, a first support unit, a belt clamp, and a first drive unit. The first support unit includes a first shaft extending in a second direction perpendicular to the first direction. The first support unit is configured to rotatably support the first belt on the arm housing. The belt clamp secures the first belt to the tip housing. The first drive unit is configured to drive the first belt. The at least one movement mechanism is configured to transmit power to an end effector attached to a free end of the tip housing. The at least one operating mechanism includes a second belt housed in the arm housing, a second support unit, and a second drive unit. The second support unit includes a second shaft extending in the second direction. The second support unit is configured to rotatably support the second belt on the arm housing. The second drive unit is configured to rotate the second belt. The guide unit is provided on the arm housing. The guide unit is configured to guide the extension and contraction of the arm housing in the first direction. The first belt and the second belt are arranged in a first region within the arm housing in the second direction. The guide unit is arranged in a second region within the arm housing that is different from the first region in the second direction. This embodiment provides a robot arm in which a first region where the first belt and the second belt are arranged and a second region where a guide unit that guides the extension and contraction of the arm housing is arranged are separated in the second direction. In the second direction, the first belt and the second belt do not overlap with the guide unit.Therefore, when assembling a robot arm by arranging multiple belts and guide units in the arm housing, the complexity of the assembly is suppressed. Furthermore, because the multiple belts and guide units are arranged separately in the second direction, interference between the multiple belts and the guide units is suppressed. In this embodiment, the end effector may be directly or indirectly attached to the free end of the robot arm. The end effector may include a robot wrist attached to the free end. The first drive unit may be configured to directly or indirectly drive the first belt. The second drive unit may be configured to directly or indirectly drive the second belt.

[0227] <2> In the above item <1>, the first drive unit may include an electric first motor. The second drive unit may include an electric second motor. The first motor and the second motor may be disposed at a base end of the arm housing opposite the free end in the first direction. According to this aspect, since the first motor and the second motor are disposed at the base end, the mass at the free end of the robot arm is reduced. This improves the operability of the robot arm. Furthermore, the power required for operation of the robot arm is reduced.

[0228] <3> In the above item <1> or <2>, the at least one movement mechanism may be a plurality of movement mechanisms. The robot arm may further include a multiple shaft provided at the free end and extending in the second direction. The multiple shaft may have a first portion housed in the tip housing and a second portion protruding from the tip housing. The multiple shaft may be configured to be operably coupled to each of the second belts of the plurality of movement mechanisms at the first portion and to receive rotational power of each of the second belts. The multiple shaft may be configured to output rotational power of each of the second belts at the second portion. According to this aspect, there is no need to provide a shaft for inputting power of the second belt to each movement mechanism and outputting power to the end effector, thereby reducing the complexity of the configuration and assembly of the robot arm. Furthermore, the robot arm is prevented from becoming large.

[0229] <4> In the above item <3>, the multiple shaft may include a plurality of hollow shafts corresponding to the plurality of operating mechanisms. The diameters of the plurality of hollow shafts may be different from one another. The lengths of the plurality of hollow shafts in the second direction may be different from one another. Each of the plurality of hollow shafts may be provided with a transmission unit in a portion of the first section that is not covered by other hollow shafts. In each of the plurality of operating mechanisms, the rotational power of the second belt may be input via the transmission unit. According to this aspect, the power of each second belt is input to the first section of the multiple shaft via the respective transmission unit.

[0230] <5> In any of the above items <1> to <4>, the at least one operating mechanism may include a second mechanism. The second belt of the second mechanism may be arranged parallel to the first belt in a third direction perpendicular to the first direction and the second direction. According to this aspect, a robot arm is provided in which the first belt and the second belt are arranged parallel to each other in the third direction. In this aspect, the third direction may be the width direction of the arm housing. Arranging the second belt parallel to the first belt in the third direction may mean that the first belt and the second belt do not overlap in the third direction. In this aspect, the first belt and the second belt may further overlap in the first direction and the second direction. According to this aspect, it is possible to prevent the robot arm from becoming large in size in the first direction and the second direction.

[0231] <6> In the above item <5>, the arm housing may include a central axis extending in the first direction. The central axis may pass through a center point of the arm housing in the third direction. The second belt and the second support part of the second mechanism may be disposed symmetrically to the first belt and the first support part with respect to an imaginary plane that includes the central axis and is parallel to the second direction. This aspect improves the balance of the robot arm in the third direction.

[0232] <7> In the above item <6>, the at least one operating mechanism may further include a first mechanism and a third mechanism. The second belt included in the first mechanism may be arranged side by side with the first belt in the second direction. The second belt included in the third mechanism may be arranged symmetrically with the second belt included in the first mechanism with respect to the imaginary plane. According to this aspect, the first belt and three second belts are efficiently arranged in the first region of the arm housing.

[0233] <8> In the above item <7>, at least a portion of the first support portion of the telescopic mechanism may extend in the second direction to support the first belt of the first mechanism. At least a portion of the second support portion of the second mechanism may extend in the second direction to support the second belt of the third mechanism. According to this aspect, at least a portion of the first support portion and at least a portion of the second support portion of the first mechanism are shared. Furthermore, at least a portion of the second support portion of the second mechanism and at least a portion of the second support portion of the third mechanism are shared. This prevents an increase in the number of parts of the robot arm. This prevents the assembly of the robot arm from becoming complicated. Furthermore, this prevents the robot arm from becoming large.

[0234] <9> In any of the above items <1> to <8>, the robot arm may include an adjustment unit configured to adjust the tension of at least one of the first belt and the second belt. The adjustment unit may include a holding unit, a wall, and an adjustment shaft. The holding unit may be provided at a tip end of at least one of the housings. The holding unit may be configured to hold at least one of the first shaft and the second shaft. The wall may be provided at the tip end. The wall may have a hole that penetrates the wall in the first direction and reaches the holding unit. The adjustment shaft may be configured to be inserted through the hole and move the holding unit in the first direction. According to this aspect, since the adjustment unit is provided on the wall at the tip end of the housing, the belt tension can be adjusted from outside the robot arm. This makes it easy to maintain the robot arm. Furthermore, when the holding unit holds the first shaft, the tension of the first belt can be adjusted by moving the first shaft in the first direction via the holding unit. Furthermore, when the holding portion holds the second shaft, the tension of the second belt can be adjusted by moving the second shaft in the first direction via the holding portion.

[0235] <10> In any of the above items <1> to <9>, the robot arm may further include a cable housing provided within the arm housing. The cable housing may be configured to expand and contract in the first direction as the arm housing expands and contracts. The cable housing may be provided in a third region opposite the second region with respect to the first region in the second direction. According to this aspect, the cable can be arranged in the cable housing provided in the third region separated from the first region in which the belts are arranged. Therefore, interference between the cable and multiple belts is suppressed. Furthermore, when the cable is arranged within the robot arm, the assembly of the robot arm is not complicated. Furthermore, the cable can be protected compared to a configuration in which the cable is arranged outside the robot arm.

[0236] <11> In <3> above or any of <4> to <10> directly or indirectly depending on <3> above, the robot arm may further include a cable housing provided within the arm housing. The cable housing may be configured to expand and contract in the first direction as the arm housing expands and contracts. The cable housing may be provided in a third region opposite the second region with respect to the first region in the second direction. The interior of the multiple shaft may be in communication with the interior of the cable housing. According to this aspect, a cable can be arranged from the base end of the robot arm to an end effector via the cable housing and the multiple shaft.

[0237] <12> In any of the above items <1> to <11>, the at least one housing included in the arm housing may include the tip housing, the base housing, and an intermediate housing incorporated between the tip housing and the base housing in the first direction. The first shaft may be provided at the free end and base end of the tip housing, the tip end and base end of the intermediate housing, and the tip end and base end of the base housing, respectively, to support the first belt within the arm housing. The tip housing may move in the first direction relative to the base housing and the intermediate housing in response to the first belt being rotated by the first drive unit. The intermediate housing may move in the first direction relative to the base housing in response to the movement of the tip housing in the first direction. According to this aspect, interference between the multiple belts and the guide unit is suppressed when the arm housing including the tip housing, the intermediate housing, and the base housing extends or retracts.

[0238] <13> According to a second aspect of the present disclosure, there is provided a robot including the robot arm according to any one of <1> to <12>. According to this aspect, there is provided a robot including a telescopic robot arm in which interference between a plurality of belts and a guide portion is suppressed.

[0239] <14> In the above item <13>, the robot may include the robot arm and a robot wrist as the end effector attached to the free end of the robot arm. According to this aspect, a robot is provided that includes a robot wrist that can operate with degrees of freedom corresponding to the number of operation mechanisms.

[0240] <15> In the above item <14>, the at least one movement mechanism may include a first mechanism, a second mechanism, and a third movement mechanism. The first mechanism may be configured to transmit power for rotating the robot wrist. The second mechanism may be configured to transmit power for causing the robot wrist to perform an up-and-down movement. The third mechanism may be configured to transmit power for causing the robot wrist to perform a pitch movement. According to this aspect, there is provided a robot including a robot arm that can output, to a robot wrist, power for rotating the robot wrist, power for causing the robot wrist to perform an up-and-down movement, and power for causing the robot wrist to perform a pitch movement.

[0241] 1: robot, 10: robot control device, 11: dolly, 12: lifting device, 15: imaging device, 100: robot system, 101: control device, 110: main body, 111: upper surface, 112: recess, 120: support, 190: hand, 191: mounting portion, 192: mounting surface, 2: drive unit, 20: control mechanism, 200, 201, 202: shaft, 21, 211, 212: shaft, 22, 221, 222, 223:, 23, 231, 232: shaft, 301, 302, 303, 304, 305 , 306, 307, 311, 312, 313, 314, 315, 321, 322, 323, 324, 331, 332, 333: Rotating bodies, E01, E02, E03, E04, E05: Belt, 160a: First differential device, 160b: Second differential device, 160c: Third differential device, 160d: Fourth differential device, 17: Correction unit, 171: First reduction unit, 172: Second reduction unit, 173: Third reduction unit, A1: First correction unit, A2: Second correction unit, A3: Third correction unit, A4: Fourth correction unit, 4: Robot axis arm, 40: arm housing, 401, 402, 403: upper wall, 404: base end, 405: free end, AP: imaginary plane, AX: central axis, 41: tip housing, 41b: rear end of tip housing, 411: extension, 412: protrusion, 42: intermediate housing, 42b: rear end of intermediate housing, 42f: front end of intermediate housing, 421: extension, 422, 423: protrusion, 43: base housing, 43f: front end of base housing, 431: extension, 432, 433: protrusion portion, 44: cable housing, 441: tip accommodating portion, 441s: tip portion, 442: intermediate accommodating portion, 443: base end accommodating portion, 443s: rear end portion, 45: guide portion, 451, 452: carriage, 451g, 452g: groove, 454, 455: rail, Ar1: first region, Ar2: second region, Ar3: third region, 47: extension mechanism, 471: belt, 472: belt clamp, 473: drive portion, 48: support portion, 481f, 481b, 481c, 482f, 482b, 482c, 482f,483f: shaft, 485: rotor, 6: multiple shaft, 60: internal space, 601: first part, 602: second part, 605u, 605d: bearing part, 606: spacer, 607: ring member, 61: first hollow shaft, 61d: lower end of first hollow shaft, 61u: upper end of first hollow shaft, 611: rotor, 613: flange, 62: second hollow shaft, 62d: lower end of second hollow shaft, 62u: upper end of second hollow shaft, 621, 622: rotor, 63: third hollow shaft, 63d: 3: Lower end of hollow shaft, 63u: Upper end of third hollow shaft, 631, 632: Rotating body, 7: Robot wrist, 70: Wrist housing, 701d: Lower wall, 701f: Front end wall, 701s: Side wall, 701u: Upper wall, 702: Opening, 703: Belt accommodating section, 704: Base end, 705: Tip end, 706: Sensor accommodating section, 705a: Opening, 706b: Partition wall, 706h: Through hole, 707d, 707u: Rail, 72: Driven shaft, 722, 732: Rotating body, 741: Holding member, 742: Adjusting shaft, 8 : Lifting operation unit, 80: Link mechanism, 81: First link unit, 812: Moving joint shaft, 814: First end, 815: Second end, 821: Rack gear, 822: Tip joint shaft, 84: Second link unit, 841: Base end, 842: Connecting end, 843, 844: Shaft, 801s: Side wall, 803, 804: Holding block, 804b, 804f: Protrusion, 804d: Extension, 805, 806: Carriage, 807, 808: Belt clamp, 808m: Block member, 809: Storage unit, 810: Case ing, 811c: upper cover, 811d: bottom wall, 811d1: first bottom wall, 811d2: second bottom wall, 811s: side wall, 813: lower cover, 50: operating mechanism, 51: first mechanism, 52: second mechanism, 53: third mechanism, 515: rotating body, 510, 520, 530: support portion, 516, 526, 536: driving portion, 511, 512: shaft, 54: adjustment portion, 541: holding portion, 542: recess, 544: hole, 545: front end wall, 546: through hole, 548: adjustment shaft, 9: pitch operating portion, 91: transmission mechanism, 912,922: Rotating body, 921: Rack gear, 931: Pinion gear, 150: Structure, 131: First motor, 132: First shaft, 133: First housing, 133s: Central axis of first housing, 139: Rotating body, 140: Second housing, 141: Second motor, 142: Second shaft, 144: Rotating body, 145: Belt, 146: Shaft, 147: Second housing, CP: Coupling portion, 20a: Control mechanism, 160: Differential device, 161 : first differential shaft, 162: second differential shaft, 161f, 162f: flange, 161p, 162p: slide plate, 163: rotating body, 164: accommodation portion, 165: ball, 166: shaft member, 170: speed reducer, D: diameter, Dθ: movement amount, θ: rotation angle, ω: rotation amount, 150n: structure of comparative example, 132n: first shaft, 142n: second shaft, 143n: rotating body, 144n: rotating body, 2n: drive portion of comparative example, 21n, 2 2n, 23n: shafts, 312n, 323n, 331n: rotating bodies, E1, E11, E2, E21, E22, E3, E31, E32, E33: belts, AX202, AX21, AX22, AX23, AX61, AX62, AX63, AX72, AX812, AX822, AX843, AX844, ax1, ax2, ax3, ax4: central axes, ax1, ax2, ax3, ax4: central axes, P: pitch axis, T: turning axis, H: working shaft Pace, C1: First container, C2: Second container, S: Shelf, s1: Shelf board, M, M1, M2, M3, M4: Motor, R: Rotary encoder, R1, R2, R3, R4, R5, R51, R6, R61, R7, R8, R81, R82: Rotation direction, TL: Torque limiter, U: Elevation axis, V: Advance / retreat axis, W: Work, r1, r2, r3, r4, r5, r51, r6, r61, r7, r72, r8, r82, r9, r91, r92: Rotation direction,

Claims

A robotic arm, a telescopic arm housing extending in a first direction and including a plurality of housings including a tip housing and a base housing capable of accommodating the tip housing; an extension / contraction mechanism that extends and contracts the arm housing in the first direction, a first belt housed in the arm housing; a first support portion including a first shaft extending in a second direction perpendicular to the first direction, the first support portion supporting the first belt rotatably on the arm housing; a belt clamp that fixes the first belt to the tip housing; an expansion / contraction mechanism including a first drive unit that drives the first belt; at least one actuation mechanism for transmitting power to an end effector attached to a free end of the tip housing, a second belt housed in the arm housing; a second support portion including a second shaft extending in the second direction and rotatably supporting the second belt on the arm housing; at least one operating mechanism including a second drive for rotating the second belt; a guide portion provided in the arm housing to guide extension and contraction of the arm housing in the first direction, the first belt and the second belt are disposed in a first region within the arm housing in the second direction; The guide portion is disposed in a second region different from the first region in the arm housing in the second direction. Robotic arm.

2. The robot arm of claim 1, the first drive unit includes an electric first motor, the second drive unit includes an electric second motor, A robot arm, wherein the first motor and the second motor are arranged at a base end of the arm housing opposite the free end in the first direction.

2. The robot arm of claim 1, the at least one movement mechanism is a plurality of movement mechanisms; the robot arm further comprises multiple shafts disposed at the free end and extending in the second direction; The multiple shafts include: a first portion housed within the tip housing and a second portion protruding from the tip housing; the first portion is operably connected to each of the second belts of the plurality of operating mechanisms, and configured to receive rotational power from each of the second belts; A robotic arm configured to output rotational power for each of the second belts at the second portion.

4. The robot arm of claim 3, the multiple shafts include a plurality of hollow shafts corresponding to the plurality of operating mechanisms; The diameters of the hollow shafts are different from one another, The lengths of the plurality of hollow shafts in the second direction are different from one another, Each of the plurality of hollow shafts has a transmission part provided in a part of the first section that is not covered by other hollow shafts, The rotational power of each of the second belts in the plurality of operating mechanisms is input via the transmission unit.

2. The robot arm of claim 1, the at least one operating mechanism includes a second mechanism; The second belt of the second mechanism is arranged alongside the first belt in a third direction perpendicular to the first direction and the second direction.

6. The robot arm of claim 5, a robot arm, wherein the second belt and the second support portion of the second mechanism are disposed symmetrically with the first belt and the first support portion with respect to an imaginary plane that includes a central axis of the arm housing extending in the first direction and is parallel to the second direction.

7. The robot arm of claim 6, the at least one operating mechanism further includes a first mechanism and a third mechanism; the second belt of the first mechanism is arranged alongside the first belt in the second direction, The second belt of the third mechanism is disposed symmetrically to the second belt of the first mechanism with respect to the imaginary plane.

8. The robot arm of claim 7, at least a portion of the first support portion of the extension mechanism extends in the second direction to support the first belt of the first mechanism; At least a portion of the second support portion of the second mechanism extends in the second direction to support the second belt of the third mechanism.

2. The robot arm of claim 1, an adjustment unit that adjusts the tension of at least one of the first belt and the second belt, a holding portion provided at a tip end of at least one of the housings, the holding portion holding at least one of the first shaft and the second shaft; a wall provided at the tip portion, the wall having a hole portion that penetrates the wall in the first direction and reaches the holding portion; an adjustment shaft configured to be inserted through the hole and move the holding portion in the first direction.

2. The robot arm of claim 1, A robot arm comprising: a cable housing provided within the arm housing, the cable housing extending and contracting in the first direction as the arm housing extends and contracts, and the cable housing being provided in a third region opposite the second region with respect to the first region in the second direction.

4. The robot arm of claim 3, a cable housing provided in the arm housing, the cable housing expanding and contracting in the first direction as the arm housing expands and contracts, and the cable housing being provided in a third region on an opposite side of the second region with respect to the first region in the second direction; The interior of the multiple shafts communicates with the interior of the cable housing.

2. The robot arm of claim 1, the at least one housing included in the arm housing includes the tip housing, the base housing, and an intermediate housing incorporated between the tip housing and the base housing in the first direction; the first shaft is provided at the free end and the base end of the tip housing, at the tip end and the base end of the intermediate housing, and at the tip end and the base end of the base housing, respectively, and supports the first belt within the arm housing; the distal housing moves in the first direction relative to the proximal housing and the intermediate housing in response to the first belt being rotated by the first driving unit; The intermediate housing moves in the first direction relative to the base housing in response to movement of the tip housing in the first direction. 　 A robot comprising the robot arm according to claim 1. 　 The robot according to claim 13, the robot arm; a robot wrist as the end effector attached to the free end of the robot arm.

15. The robot of claim 14, the at least one operating mechanism includes a first mechanism, a second mechanism, and a third mechanism; the first mechanism transmits power to rotate the robot wrist; the second mechanism transmits power to the robot wrist to perform a lifting operation; The third mechanism transmits power to the robot wrist to cause it to perform a pitch movement.

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