Robot list and robots

Abstract

This helps to suppress the increasing size of the configuration required to operate the robot list. [Solution] The robotic wrist comprises a housing having an opening at the bottom, a first drive shaft, a first driven shaft, a first endless member, and a linkage mechanism. The linkage mechanism constitutes a Scott-Russell linkage. The first linkage section comprises a movable link and an end link. The second linkage section comprises a first connecting link and a second connecting link. The movable link is configured to move in a first direction within the housing by the rotation of the first endless member. The end link is configured to move in a second direction in response to the movement of the movable link in the first direction. At least a portion of the linkage mechanism is exposed to the outside of the housing in response to the forward movement of the movable link and retracted into the housing through the opening in response to the backward movement of the movable link.

Description

Technical Field

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

Background Art

[0002] Conventionally, a robot arm with a hand connected thereto is known. In the robot arm described in Patent Document 1, the hand is linearly moved from a state where the robot arm has stopped. Thus, even without moving the robot arm, the hand can access the workpiece only by moving the hand.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to expand the movement range of the hand, it is conceivable to provide a robot list between the robot arm and the hand. However, there are concerns about complication of the configuration for operating the robot list and enlargement of the robot list.

Means for Solving the Problems

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

[0006] A robotic wrist is provided according to a first embodiment of the present disclosure. The robotic wrist comprises a housing extending in a first direction, a first drive shaft, a first driven shaft, a first endless member, and a link mechanism. The housing comprises a housing base portion and a housing tip portion. The housing tip portion is provided on the side opposite to the housing base portion in the first direction. The housing has a bottom portion in a second direction intersecting the first direction. The bottom portion is provided with an opening. The first drive shaft is provided at the housing base portion and extends in the second direction. The first driven shaft is provided at the housing tip portion and extends in the second direction. The first endless member is stretched between the first drive shaft and the first driven shaft. The first endless member rotates within the housing by the rotational power of the first drive shaft. The link mechanism comprises a first link portion and a second link portion, and constitutes a Scott-Russell link. The first link portion comprises a movable link and a tip link. A mounting portion is connected to the tip section. The mounting portion is configured to allow the attachment of an end effector. The second link section comprises a first connecting section and a second connecting section. The first connecting section is rotatably connected to the first link section between the movable section and the tip section. The second connecting section is rotatably connected to the housing at the front end of the housing. The movable section is configured to move in a first direction within the housing by the rotation of the first endless member. The tip section is configured to move in a second direction in response to the movement of the movable section in the first direction. At least a portion of the link mechanism is configured to be exposed to the outside of the housing in response to the movement of the movable section in the forward direction from the base end of the housing to the front end of the housing in the first direction. At least a portion of the link mechanism is configured to be housed inside the housing through the opening in response to the movement of the movable section in the rearward direction opposite to the forward direction.

[0007] According to a second embodiment of this disclosure, a robot comprising the robot list is provided. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing a robotic system equipped with a robot. [Figure 2] This is a schematic diagram illustrating an example of a pick-and-place operation. [Figure 3] This is a perspective view of a robotic arm in its retracted state. [Figure 4] This is a perspective view of a robot arm in its extended state. [Figure 5] This is a side view of the robot arm in its retracted state. [Figure 6] This is a side view of the robot arm in its extended state. [Figure 7] This is a top view of the robot arm in its extended state. [Figure 8] This is a perspective view of a retracted robot arm with the upper wall of the arm housing removed, and is intended to illustrate the cable housing. [Figure 9] This is a perspective view of the robot arm in its extended state, with the upper wall of the arm housing removed, and is intended to illustrate the cable housing. [Figure 10] This is a cross-sectional view of XX in Figure 5. [Figure 11] Figure 7 is a cross-sectional view of section XI-XI, which is a diagram used to explain the guide section. [Figure 12] This is a perspective view of the robot arm, excluding a portion of the arm housing. [Figure 13] This is a perspective view of the robot arm excluding the arm housing, and is a diagram used to explain the extension / retraction mechanism and the operating mechanism. [Figure 14] Figure 5 is a cross-sectional view of section XIV-XIV, showing the inside of the arm housing in the retracted state of the robot arm. [Figure 15] This is a cross-sectional view of the robot arm in its extended state, corresponding to Figure 14. [Figure 16] Figure 7 is a cross-sectional view taken along line XVI-XVI, illustrating the adjustment mechanism. [Figure 17]It is a sectional view taken along line XVII-XVII of FIG. 16, and is a diagram for explaining the adjustment part. [Figure 18] It is a perspective view of a part of the multi-shaft cut away. [Figure 19] It is a sectional view of the multi-shaft and the robot wrist including the pivot axis and perpendicular to the Y-axis. [Figure 20] It is an explanatory diagram showing the drive part. [Figure 21] It is a perspective view of the robot arm and the robot wrist attached to the robot arm. [Figure 22] It is a perspective view of the robot wrist in the uppermost raised state. [Figure 23] It is a side view of the robot wrist in the uppermost raised state. [Figure 24] It is a front view of the robot wrist in the uppermost raised state. [Figure 25] It is a top view of the robot wrist in the uppermost raised state. [Figure 26] It is a bottom view of the robot wrist in the uppermost raised state. [Figure 27] It is a perspective view of the robot wrist in the lowermost lowered state. [Figure 28] It is a side view of the robot wrist in the lowermost lowered state. [Figure 29] It is a perspective view of the robot wrist in the uppermost raised state, and is a diagram for explaining the inside of the wrist housing. [Figure 30] It is another perspective view of the robot wrist in the uppermost raised state, and is a diagram for explaining the inside of the wrist housing. [Figure 31] It is a sectional view taken along line XXXI-XXXI of FIG. 25. [Figure 32] It is a sectional view taken along line XXXII-XXXII of FIG. 25. [Figure 33] It is a left side view of the robot wrist in the uppermost raised state excluding the left part of the wrist housing, and is a diagram for explaining the operation of the link mechanism. [Figure 34]This is a left side view of the robot wrist in its lowest position, excluding the left portion of the wrist housing, and is a diagram used to explain the operation of the link mechanism. [Figure 35] This is a cross-sectional view from XXXV-XXXV in Figure 24. [Figure 36] This is a cross-sectional view taken from XXXVI-XXXVI in Figure 25. [Figure 37] This figure corresponds to Figure 36 and shows how the mounting part rotates due to the pitch movement unit. [Figure 38] This is a diagram showing the drive unit of an comparative example. [Figure 39] This table shows each operation in the robot arm and robot wrist, and the rotation direction and amount of rotation of each belt required for each operation to be performed independently. [Figure 40] This figure shows a reference example structure having two movable parts in a dependent relationship. [Figure 41] Figure 40 is a diagram illustrating how the second movable part follows the first movable part, using the XLI-XLI cross-sectional view, and shows the structure in its initial state. [Figure 42] This figure shows how the second housing rotates relative to the first housing as the first housing rotates from the initial state shown in Figure 40. [Figure 43] This figure shows how, by rotating the rotating body and shaft, only the first housing is rotated while the positional relationship between the first and second housings remains in its initial state. [Figure 44] This is a schematic diagram showing a structure to which a control mechanism is applied. [Figure 45] This is a schematic longitudinal cross-sectional view of a differential. [Figure 46] This diagram illustrates the rotation of the balls and the amount of shaft movement when the rotating body of the differential is fixed. [Figure 47] This diagram illustrates the rotation between one shaft and another shaft when the rotating body is fixed. [Figure 48]This diagram illustrates the rotation of the balls and the amount of movement of the other shaft when one shaft of a differential is fixed. [Figure 49] This diagram illustrates the rotation of a rotating body and another shaft when one shaft is fixed. [Figure 50] Figure 44 is a cross-sectional view of LL. [Figure 51] This diagram illustrates how the relationship between the first and second movable parts is canceled out by the control mechanism. [Figure 52] This is a diagram illustrating the reduction gear and differential in the drive unit. [Figure 53] This diagram illustrates the power transmission path during arm extension. [Figure 54] This diagram illustrates the power transmission path during wrist rotation. [Figure 55] This diagram illustrates the power transmission path during the lifting motion of a wristband. [Figure 56] This diagram illustrates the power transmission path during wrist pitching. [Modes for carrying out the invention]

[0009] <Robot System> Figure 1 is a schematic diagram showing a robot system 100 comprising a robot 1 as one embodiment of the present disclosure. The robot system 100 comprises a robot 1 and a control device 101 that controls the robot 1. The robot 1 performs a pick-and-place operation, for example, transporting a workpiece W placed at a transfer source to a transfer destination. In Figure 1, the robot 1 picks up the 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 multiple shelves s1 arranged at intervals in the vertical direction. The first container C1 is placed on one of the shelves s1. In the shelf S, there is a workspace H between the first container C1 and the shelf s1 located above the first container C1, into which the robot arm 4 of the robot 1 can enter.

[0011] Robot 1 comprises 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 moves the hand 190 using the robot arm 4 and the robot wrist 7.

[0012] Robot 1 further comprises a trolley 11 and a lifting device 12 positioned on the trolley 11 that supports the robot arm 4 so that it can be raised and lowered. The trolley 11 is, for example, an AGV (Automated Guided Vehicle). Robot 1 moves by the movement of the trolley 11. The trolley 11 includes a box-shaped body 110. The 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 surface for placing containers or the like. In the example shown in Figure 1, a second container C2 is loaded on the upper surface 111.

[0013] The lifting device 12 raises and lowers the robot arm 4 and also rotates it. The lifting device 12 has a support column 120 that extends in the vertical direction. The central axis of the support column 120 is also called the lifting axis U. The support column 120 is mounted on the trolley 11 so as to be rotatable about the lifting axis U. In the example shown in Figure 1, the support column 120 is mounted on a recess 112 of the trolley 11. The lifting device 12 includes a rotary actuator configured to rotate the support column 120 about 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 robot arm 4 about the lifting axis U by rotating the support column 120 about the lifting axis U using the rotary actuator. 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 forward / backward axis V. The direction of the forward / backward axis V is also the first direction. The forward / backward axis V and the lifting axis U are in a vertical relationship. In this embodiment, the robot arm 4 is mounted on the lifting device 12 such that the forward / backward 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 forward / backward axis V. The arm housing 40 includes a plurality of cylindrical housings. By the relative movement of the plurality of cylindrical housings in the direction of the forward / backward axis V, the robot arm 4 extends and retracts in the first direction. The robot arm 4 is also simply called the "arm".

[0015] The robot wrist 7 is pivotably attached to the tip of the robot arm 4. The pivot axis T (see Figure 2) of the robot wrist 7 extends in a second direction perpendicular to the first direction. The tip of the robot wrist 7 is provided with a mounting portion 191 for detachably attaching the hand 190. The robot wrist 7 moves the hand 190 in the second direction by moving the mounting portion 191 in the second direction. The robot wrist 7 has a pitch axis P that extends in a predetermined direction at the mounting portion 191. In the example shown in Figure 1, the pitch axis P is perpendicular to the first and second directions. The robot wrist 7 rotates the hand 190 around the pitch axis P. The rotational movement around the pitch axis P is also called the "wrist pitch movement".

[0016] In Figure 1 and subsequent 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 called the forward direction, and the -X-axis direction is also called 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 and down direction. The +Z-axis direction is the upward direction, and the -Z-axis direction is the downward direction. In Figure 3 and subsequent figures, the Y-axis direction is shown as appropriate. The Y-axis direction is perpendicular to the X-axis and Z-axis directions. 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 axis U in the lifting device 12, but the second direction may be different from the extension direction of the lifting axis U.

[0017] The hand 190 is detachably attached to the mounting portion 191 of the robot wrist 7. The hand 190 holds the workpiece W. The hand 190 includes 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, but 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 Figure 1, the drive unit 2 is located at the base end 404, which is the -X axis end of the robot arm 4, and is integrally attached to the lifting device 12 with the robot arm 4. The drive unit 2 has a number of motors corresponding 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 Figure 20). In this embodiment, motors M, M1, M2, and M3 are servo motors with a servo lock function.

[0019] The drive unit 2 further includes a control mechanism 20. The control mechanism 20 is configured to operate a plurality of movable parts that are in a dependent relationship with each other independently. A dependent relationship refers to a relationship in a structure having a plurality of movable parts, including a first movable part and at least one second movable part, where when the first movable part is operated, at least one second movable part operates 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 later.

[0020] Robot 1 further includes an imaging device 15. The imaging device 15 may include a camera having an optical system and a two-dimensional image sensor. In the example shown in Figure 1, the imaging device 15 is mounted on the hand 190. The imaging device 15 may be mounted on the walls or ceiling around Robot 1, or on the robot arm 4 or robot wrist 7, instead of or in addition to the hand 190. The imaging device 15 acquires images of the first container C1 and the second container C2.

[0021] The control device 101 comprises a processor such as a CPU that performs various calculations and a memory device. The memory device includes, for example, non-volatile memory and volatile memory. The CPU controls the robot 1 by loading and executing various programs stored in the memory. The control device 101 outputs commands to the robot control device 10 of the robot system 100 for, for example, moving the robot arm 4 along the lifting axis U, rotating the robot arm 4, or extending and retracting the robot arm 4. The robot control device 10 comprises a processor such as a CPU that performs various calculations and a memory device. The memory device includes, for example, non-volatile memory and volatile memory. The CPU of the robot control device 10 controls the actuators and motors M, M1, M2, and M3 in the lifting device 12 in response to commands from the control device 101 by loading and executing various programs stored in the memory.

[0022] Using Figure 2, we will briefly explain the pick-and-place operation of workpiece W by robot 1. The control device 101 outputs a command to the robot control device 10, causing robot 1 to move its trolley 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 work space H between the target first container C1 and the shelf s1 located above it. Next, robot 1 extends the robot arm 4 to bring it into the work space H. This brings the robot wrist 7 and hand 190 into the work space H. Furthermore, robot 1 moves the hand 190 above the workpiece W to be grasped via the robot wrist 7. In the example shown in Figure 2, robot 1 rotates the hand 190 around the pitch axis P via the robot wrist 7. Also, 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 (suction) the workpiece W.

[0023] When the robot grasps the workpiece W, it 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 to move the workpiece W, the hand 190, the robot wrist 7, and the robot arm 4 out of the workspace H. The robot 1 rotates and raises the lifting device 12 to move the hand 190 to the upper part of the second container C2. The robot 1 places the workpiece W inside the second container C2 by releasing the grip of the workpiece W from the hand 190. In this way, the workpiece W to be grasped 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 using Figures 3 to 20. Figure 3 is a perspective view of the robot arm 4 in its retracted state. Figure 4 is a perspective view of the robot arm 4 in its extended state. The robot arm 4 has a telescopic structure. Figure 3 shows the robot arm 4 in its most retracted state, and Figure 4 shows the robot arm 4 in its most extended state. Hereafter, the most extended state of the robot arm 4 will also be referred to as the "longest state," and the most retracted 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 changes between the longest and shortest states.

[0025] The robot arm 4 mainly comprises an arm housing 40, an extension / retraction mechanism 47 (see Figures 10 and 13), an operating mechanism 50 (see Figure 12), and a guide section 45 (see Figure 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 section 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 the pivot axis T. The robot wrist 7 raises and lowers the hand 190 via the mounting part 191. The robot wrist 7 also rotates the hand 190 around the pitch axis P via the mounting part 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 part 191, and rotation of the mounting part 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 to rotate the robot wrist 7, a second mechanism 52 that transmits power to raise and lower the hand 190 via the mounting part 191, and a third mechanism 53 that transmits power to pitch the hand 190 via the mounting part 191. The telescopic mechanism 47 and the operating mechanism 50 will be described in detail later.

[0027] <Arm Housing> The outer casing of the robot arm 4 is defined by the arm housing 40. As shown in Figures 3 to 7, the arm housing 40 comprises a plurality of housings extending in a first direction (X-axis direction). In this embodiment, the arm housing 40 comprises a base housing 43, an intermediate housing 42, and an end housing 41. As shown in Figure 7, the central axis AX of each housing 43, 42, and 41 extends in the X-axis direction. The end housing 41 is housed in the intermediate housing 42 so as to be able to move back and forth in the X-axis direction. The intermediate housing 42 is housed in the base housing 43 so as to be able to move back and forth 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 end housing 41 in the +X-axis direction. Hereinafter, the end of the end housing 41 in the -X-axis direction will also be referred to as the rear end 41b. Furthermore, the end of the intermediate housing 42 in the +X axis direction is also called the front end 42f, and the end in the -X axis direction is also called the rear end 42b, and the end of the base housing 43 in the +X axis direction is also called the 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 housing 43, intermediate housing 42, and tip housing 41 in the Y-axis direction decrease in this order. For the sake of explanation, below, when viewing the robot arm 4 from the base end 404 in the direction of the +X axis, the direction to the right will be referred to as the +Y axis direction, and the opposite direction will be referred to as the -Y axis direction.

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

[0030] As shown in Figures 9 and 10, the tip housing 41 comprises an extended portion 411 extending in the X-axis direction and a pair of protrusions 412 provided at the rear end portion 41b. As shown in Figure 10, the pair of protrusions 412 are connected to the extended portion 411 and protrude away from the virtual plane AP.

[0031] The intermediate housing 42 comprises an extending portion 421 extending in the X-axis direction, a pair of protrusions 422 provided at the rear end portion 42b, and a pair of protrusions 423 provided at the front end portion 42f. As shown in Figure 10, the pair of protrusions 422 are connected to the extending portion 421 and project away from the virtual plane AP. The pair of protrusions 423 are connected to the extending portion 421 and project towards the virtual plane AP.

[0032] The base housing 43 comprises an extended portion 431 and a pair of protruding portions 433 provided at the front end portion 43f. The protruding portions 433 are connected to the extended portion 431 and protrude in a direction toward the virtual plane AP.

[0033] As shown in Figures 8 and 9, the protrusion 412 of the tip housing 41 is positioned behind 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 detaching from the intermediate housing 42. Also, the protrusion 422 of the intermediate housing 42 is positioned behind 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 detaching from the intermediate housing 42.

[0034] <Cable Housing> As shown in Figures 8 and 9, the robot arm 4 further includes a cable housing 44 extending in the X-axis direction. As shown in Figure 10, the cable housing 44 is located in the upper part of the arm housing 40. The cable housing 44, like the arm housing 40, has a telescopic structure.

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

[0036] The cable housing 44 can accommodate cables connected to sensors such as the hand 190 or the imaging device 15 mounted on the hand 190. This prevents the cables from becoming entangled with the belts 471, E1, E2, and E3 due to the extension and retraction of the robot arm 4. Furthermore, the cables can be easily positioned on the robot arm 4. This simplifies the assembly of the robot arm 4.

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

[0038] The carriage 451 is provided at the lower end of the projection 412 of the tip housing 41. The rail 454 is provided at positions corresponding to the range of movement of the projection 412 in the +Y axis direction and -Y axis direction of the extension 421 of the intermediate housing 42. As the telescopic mechanism 47 extends and retracts the arm housing 40, the carriage 451 slides along the rail 454, guiding the tip housing 41 in the X axis direction relative to the intermediate housing 42.

[0039] The carriage 452 is provided at the lower end of the projection 422 of the intermediate housing 42. The rail 455 is provided at positions corresponding to the range of movement of the projection 422 in the +Y axis direction and -Y axis direction of the extension 431 of the base housing 43. As the extension mechanism 47 extends and retracts the arm housing 40, the carriage 452 slides on the rail 455, 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 retraction of the arm housing 40 in the X axis direction.

[0040] <Telescopic mechanism and operating mechanism> Next, the telescopic mechanism 47 and the operating mechanism 50 will be described, mainly using Figures 10, 12, and 13. The telescopic mechanism 47 includes a belt 471 for extending and retracting the arm. The operating mechanism 50 comprises a first mechanism 51, a second mechanism 52, and a third mechanism 53, as described above. Each mechanism 51, 52, and 53 includes belts E1, E2, and E3. Therefore, four belts are arranged inside the arm housing 40. Belt E1 transmits power to rotate the robot wrist 7. Belt E2 transmits power to raise and lower the robot wrist 7. Belt E3 transmits power to pitch the robot wrist 7.

[0041] As shown in Figure 10, the belt 471 for extending and retracting the arm and the belts E1, E2, and E3 for the end effectors are arranged within the arm housing 40 so as not to overlap with the guide section 45 in the Z-axis direction. Figure 10 shows a first region Ar1 where the belts 471, E1, E2, and E3 are located, and a second region Ar2 where the guide section 45 is located. In this embodiment, the second region Ar2 is located at the lower end of the arm housing 40, and the first region Ar1 is located above the second region Ar2. Figure 10 also shows a third region Ar3 where the cable housing 44 is located. The third region Ar3 is located above the first region Ar1. Thus, in this embodiment, the belts 471, E1, E2, and E3 and the guide section 45 are located in different regions in the Z-axis direction. Therefore, interference between the belts 471, E1, E2, and E3 and the guide section 45 is suppressed. In addition, the assembly of the robot arm 4 is made easier. Furthermore, the cable housing 44 is provided in a first region Ar1, a second region Ar2, and a third region Ar3 in the Z-axis direction. As a result, interference between the cable housing 44, the belts 471, E1, E2, E3, and the guide section 45 is suppressed. In addition, the assembly of the robot arm 4 is made easier.

[0042] <Extension mechanism> The telescopic mechanism 47 will now be described in detail. The telescopic mechanism 47 comprises a belt 471 for extending and retracting the arm, a support part 48, a belt clamp 472 (see Figures 13 to 15), and a drive part 473 (see Figure 20). The telescopic mechanism 47 as a whole is located in the left portion of the arm housing 40 (in the -Y axis direction with respect to the virtual plane AP). As shown in Figure 10, the belt 471 is located in the upper portion of the left portion of the first region Ar1.

[0043] The support portion 48 rotatably supports the 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 that extend in the Z-axis direction.

[0044] As shown in Figure 12, shafts 481f, 481b, and 481c are provided in the tip housing 41. Shaft 481f is fixed to the free end 405 of the tip housing 41. Shaft 481b is fixed to a projection 412 provided at the rear end of the tip housing 41. Shaft 481c is fixed to the projection 412 in front of shaft 481b.

[0045] Shafts 482f, 482b, and 482c are provided in the intermediate housing 42. Shaft 482f is fixed to a projection 423 provided at the front end of the intermediate housing 42. Shafts 482b and 481c are fixed to projections 422 provided at the rear end of the intermediate housing 42. Shaft 482c is fixed to the projection 422 in front of shaft 482f.

[0046] Shafts 483f, 202, and 21 are provided on the base housing 43. Shaft 483f is fixed to a projection 433 provided on the front end of the base housing 43. Shafts 202 and 21 are arranged side by side in the Y-axis direction on the base end 404 of the base housing 43. Shafts 202 and 21 are rotatably supported on the base housing 43.

[0047] The shafts 481f, 481b, and 481c provided in the tip housing 41, the shafts 482f, 482b, and 482c provided in the intermediate housing 42, and the shaft 483f provided in the base housing 43 are each provided with a rotating body 485 that is rotatable relative to each shaft. For clarity of the illustration, the reference numerals for the rotating bodies 485 provided on each shaft have been omitted as appropriate. The same applies to the rotating body 515 in the operating mechanism 50. In this embodiment, the protrusions 412, 422, 423, and 433 are provided with recesses on which the rotating bodies 485 can be placed. As shown in Figure 20, the shafts 202 and 21 are provided with a plurality of rotating bodies. The support portion 48 includes a rotating body 305 that rotates integrally with the shaft 202, and a rotating body 314 that is rotatable relative to the shaft 21, among the plurality of rotating bodies provided on the shaft 21. In Figure 20 and subsequent figures, the hatching on each rotating body is for distinguishing 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 located 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 power from 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 corresponding to belts E1, E2, and E3 for the end effectors.

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

[0050] In this embodiment, belts 471, E1, E2, and E3 are timing belts. Of the rotating bodies 305, 314, and 485, the rotating body that contacts the belt teeth is a toothed pulley. The rotating body that does not contact the belt teeth may be a roller. The same applies to the operating mechanism 50.

[0051] As shown in Figures 14 and 15, the belt clamp 472 secures the belt 471 to the end housing 41. In this embodiment, the belt clamp 472 is fixed to the extended portion 411 at the rear end portion 41b of the end housing 41.

[0052] The extension and retraction operation of the arm housing 40 will be explained 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. Rotation direction r2 is the opposite direction of rotation to rotation direction r1. In this embodiment, rotation direction r1 is counterclockwise and rotation direction r2 is clockwise. Note that 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, in the contracted state shown in Figure 14, when the belt 471 rotates in the direction of arrow R1, the belt 471, which is positioned from the belt clamp 472 through the intermediate housing 42 to the base housing 43, is gradually fed out in the direction of arrow R1. As a result, the free end 405 is pushed out 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 Figure 14 to the extended state shown in Figure 15.

[0054] Furthermore, when the motor M rotates the shaft 202 in the rotational direction r2 from the extended state shown in Figure 15, the belt 471 is driven to rotate in the direction of arrow R2. Since 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 positioned from the free end 405 to the base end 404 in the direction along arrow R2, is gradually fed out in the direction of arrow R2. As a result, the free end 405 moves in the -X axis direction. In other words, the tip housing 41 moves in the -X axis direction, and the intermediate housing 42 moves in the -X axis direction. As a result, the tip housing 41 is housed in the intermediate housing 42, and the intermediate housing 42 is housed in the base housing 43. In other words, the arm housing 40 contracts. Consequently, the arm housing 40 transitions from the extended state shown in Figure 15 to the contracted state shown in Figure 14.

[0055] <Operating mechanism> Next, the operating mechanism 50 will be described in detail, mainly using Figures 10 to 15 and Figure 20. As shown in Figure 12, the first mechanism 51 included in the operating mechanism 50 comprises a belt E1 that transmits power to rotate the robot wrist 7, a support part 510, and a drive part 516 (see Figure 20). The support part 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 Figures 12 and 13, the support portion 510 comprises a plurality of shafts and a rotating body provided on each shaft. The plurality of shafts include shafts 481f, 481b, and 481c provided on the tip housing 41, shafts 511, 482b, and 482c provided on the intermediate housing 42, and shafts 512, 202, and 21 provided on the base housing 43. As shown in Figure 12, among the plurality of shafts in the support portion 510, shaft 511 provided on the front end portion 42f (projection portion 423) of the intermediate housing 42 is formed separately from shaft 482f in the support portion 48 described above. Shaft 512 provided on the front end portion 43f (projection portion 433) of the base housing 43 is also formed separately from shaft 483f in the support portion 48 described above. The other shafts provided on the support portion 510 are shared with the shafts provided on the support portion 48.

[0057] A rotating body 515 is provided on each of 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. In Figure 12, only the rotating body 515 provided on shaft 481f is indicated with a reference numeral. Each rotating body 515 is freely rotatable relative to each shaft.

[0058] As shown in Figure 20, the support section 510 further includes a rotating body 307 that is rotatable relative to the shaft 202, and a rotating body 312 that is mounted on the shaft 21 and rotates with the rotation of the shaft 21. The rotating body 312 is a pulley incorporated into a ball differential (ball differential device). A pulley incorporated into a ball differential will also be called a retainer pulley below. The rotating bodies 321, 323, and 331, which will be described later, are also retainer pulleys. The rotating bodies 312, 321, 323, and 331 are each elements of a differential. The differential will be described in detail later.

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

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

[0061] As shown in Figures 12 and 13, the first mechanism 51 further includes a belt E11 positioned 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 multi-shaft 6 at the free end 405.

[0062] When the motor M1 for wrist rotation rotates the shaft 21 in the 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 the rotation direction r4, opposite to the rotation direction r3, the belt E1 rotates in the direction of arrow R4. The rotational power of belt E1 is output to the first hollow shaft 61 (described later) in the multi-shaft 6 via belt E11.

[0063] As shown in Figures 12 and 13, the second mechanism 52 included in the operating mechanism 50 comprises a belt E2 that transmits power to raise and lower the robot wrist 7, a support part 520, and a drive part 526 (see Figure 20). The second mechanism 52 as a whole is located in the right portion (in the +Y axis direction with respect to the virtual plane AP) of the arm housing 40. As shown in Figure 10, the belt E2 is located in the upper portion of the right portion of the first region Ar1.

[0064] Belt E2 is positioned symmetrically with respect to the virtual plane AP with respect to the belt 471 for extending and retracting the arm. The support portion 520 includes shafts 22 and 23 provided at the base end portion 404. The shafts 22 and 23 are positioned side by side in the Y-axis direction. The support portion 520 includes a rotating body 323 provided on shaft 22 and rotating with the rotation of shaft 22, and a rotating body 333 that is rotatable relative to shaft 23. Furthermore, at the front end portion 43f of the tip housing 41, intermediate housing 42, and base housing 43, the support portion 520 includes a shaft and rotating body provided in the support portion 48 and a shaft and rotating body positioned symmetrically with respect to the virtual plane AP. The configuration of these shafts and rotating bodies in the support portion 520 is the same as that of the shafts and rotating bodies in the support portion 48, except that they are positioned symmetrically with respect to the virtual plane AP, so a description is omitted.

[0065] As shown in Figures 13 and 20, a motor M2 for lifting and lowering the wrist is operably connected to the shaft 22. The motor M2 is located 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 power from 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 positioned at the free end 405. The belt E21 is stretched between a rotating body 485 provided on the shaft 481f in the support section 520 and a rotating body provided on the multi-shaft 6 at the free end 405.

[0067] When the motor M2 for lifting and lowering the wrist rotates the shaft 22 in the rotational direction r5 shown in Figure 14, the belt E2 rotates in the direction of arrow R5. When the motor M2 rotates the shaft 22 in the rotational direction r6, opposite to the rotational direction r5, the belt E2 rotates in the direction of arrow R6. The rotational power of belt E2 is output to the second hollow shaft 62 (described later) in the multi-shaft 6 via belt E21.

[0068] As shown in Figures 12 and 13, the third mechanism 53 included in the operating mechanism 50 comprises a belt E3 that transmits power to the hand 190 via the robot wrist 7 to perform a pitch motion, a support part 530, and a drive part 536 (see Figure 20). The support part 530 is configured to support the belt E3 in the -Z axis direction of the belt E2 on the arm housing 40.

[0069] As shown in Figure 10, belt E3 is positioned symmetrically with respect to the virtual plane AP with respect to belt E1 for wrist rotation. As shown in Figure 13, the support portion 530 includes shafts 22 and 23 provided at the base end portion 404. The support portion 530 further includes a rotating body 322 that is rotatable with respect to shaft 22, and a rotating body 331 provided on shaft 23 that rotates with the rotation of shaft 23. Furthermore, at the front ends of the tip housing 41, intermediate housing 42, and base housing 43, the support portion 530 includes the shaft and rotating body provided in the support portion 510, and a shaft and rotating body positioned symmetrically with respect to the virtual plane AP. The configuration of these shafts and rotating bodies in the support portion 530 is the same as that of the shaft and rotating body in the support portion 510, except that they are positioned symmetrically with respect to the virtual plane AP, so a description is omitted.

[0070] As shown in Figures 13 and 20, a motor M3 for pitch movement is operably connected to the shaft 23. The motor M3 is located 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 power from 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. Belt E31 is stretched between a rotating body 515 provided on a shaft 481f in the support portion 530 and a multi-shaft 6 provided at the free end 405. As shown in Figures 12, 13, and 18, belt E31 is positioned between belt E21 and belt E11 in the Z-axis direction.

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

[0073] As explained above, the belt 471 of the telescopic mechanism 47 and the belts E1, E2, and E3 of the operating mechanism 50 are arranged inside the arm housing 40. The support part 48 of the telescopic mechanism 47 and the support part 510 of the first mechanism 51 are mainly located in the left part of the first region Ar1. Most of the multiple shafts provided by the support part 48 are shared with the multiple shafts provided by the support part 510. Therefore, belt E1 can be placed below belt 471. In other words, belt 471 and belt E1 can be arranged side by side in the Z-axis direction. The support part 520 of the second mechanism 52 and the support part 530 of the third mechanism 53 are mainly located in the right part of the first region Ar1. Most of the multiple shafts provided by the support part 520 are shared with the multiple shafts provided by the support part 530. Therefore, belt E3 can be placed below belt E2. In other words, belt E2 and belt E3 can be arranged side by side in the Z-axis direction. Thus, in this embodiment of the robot arm 4, the space within the arm housing 40 can be effectively utilized to arrange multiple belts within the arm housing 40.

[0074] Furthermore, since belts 471, E1, E2, and E3 are located within the arm housing 40, for example, when belt 471 is driven by motor M, the other belts E1, E2, and E3 may also rotate in accordance with the extension and retraction of the arm housing 40. This could unintentionally cause the end effector to operate due to the first mechanism 51, the second mechanism 52, and the third mechanism 53. In this embodiment, by providing the control mechanism 20, the extension and retraction of the arm housing 40 can be performed independently by motor M alone, the rotation of the robot wrist 7 can be performed independently by motor M1 alone, the lifting and lowering of the robot wrist 7 can be performed independently by motor M2 alone, and the pitching of the robot wrist 7 can be performed independently by 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 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 part> The robot arm 4 of this embodiment further includes an adjustment unit 54 configured to adjust the tension of the belts. The adjustment unit 54 is provided for each of the belts: belt 471, belt E1, belt E2, and belt E3.

[0076] As shown in Figure 12, the adjustment section 54 of belt 471 is provided on the front end portion 43f (protrusion 433) of the left part of the base housing 43. The adjustment section 54 of belt E1 is provided on the front end portion 42f (protrusion 423) of the left part of the intermediate housing 42. The adjustment section 54 of belt E2 and the adjustment section 54 of belt E2 are provided in positions symmetrical with respect to the virtual plane AP, with respect to the adjustment section 54 of belt 471 and the adjustment section 54 of belt E1.

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

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

[0079] The front end portion 43f of the base housing 43 is provided with a through hole 546 extending in the X-axis direction. The through hole 546 penetrates the front end wall 545 that defines the base housing 43. The front end of the retaining portion 541 is provided with a hole 544 that communicates with the through hole 546. The through hole 546 and the hole 544 are configured to accommodate the shaft portion of the adjustment shaft 548. The through hole 546 and the hole 544 constitute 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 retaining portion 541 moves in the X-axis direction as the adjustment shaft 548 rotates in a predetermined direction around its axis. Therefore, the user can move the shaft 483f in the X-axis direction via the retaining portion 541 by rotating the adjustment shaft 548. 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 respective adjustment portions 54 corresponding to belts E1, E2, and E3. For example, at the front end 42f of the intermediate housing 42, the tension of belt E1 can be adjusted by moving the shaft 511 in the X-axis direction via the retaining portion 541. Similarly, the tension of 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, which are provided with adjustment portions 54.

[0081] <Multi-shaft> Next, the multi-shaft 6 will be described, mainly using Figures 18 and 19. The multi-shaft 6 is provided at the free end 405 of the robot arm 4. The multi-shaft 6 extends in the Z-axis direction. The multi-shaft 6 comprises a first portion 601 located within the tip housing 41 and a second portion 602 protruding from the tip housing 41 in the -Z-axis direction. As shown in Figure 19, the second portion 602 is located within the wrist housing 70. The multi-shaft 6 is operably connected in the first portion 601 to belts E1, E2, and E3 in the operating mechanism 50, and is configured to receive rotational power from belts E1, E2, and E3, respectively. The multi-shaft 6 is also configured to output rotational power from belts E1, E2, and E3, respectively, in the second portion 602.

[0082] The multi-shaft 6 comprises multiple hollow shafts. As shown in Figure 18, in this embodiment, the multi-shaft 6 comprises three hollow shafts: a first hollow shaft 61 for wrist rotation, a second hollow shaft 62 for wrist elevation, and a third hollow shaft 63 for pitch movement. The central axes AX61, AX62, and AX63 of the first hollow shaft 61, the second hollow shaft 62, and the third hollow shaft 63 extend in the Z-axis direction. The central axis AX61 of the first hollow shaft 61 is also the rotation axis T of the robot wrist 7. The central axes AX61, AX62, and AX63 are coaxial. The diameters of each hollow shaft are different from each other. The lengths of each hollow shaft are different from each other.

[0083] In this embodiment, the diameter of the hollow shafts is smallest for the second hollow shaft 62 and largest for the first hollow shaft 61. The third hollow shaft 63 is positioned radially outward of the second hollow shaft 62, and the first hollow shaft 61 is positioned radially outward of the third hollow shaft 63. In addition, 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 part 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 part 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 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 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 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 Figure 18, a rotating body 621 is provided at the upper end 62u of the second hollow shaft 62. As shown in Figure 19, a rotating body 622 is provided at the lower end 62d of the second hollow shaft 62. The rotating body 621 is located in the first part 601, and the rotating body 622 is in the second part 602 and is located inside the wrist housing 70. The rotating bodies 621 and 622 are fixed to the second hollow shaft 62 and rotate together with the second hollow shaft 62. The belt E21 of the second mechanism 52 is stretched over the rotating body 621. The rotation of the belt E2 of the second mechanism 52 is transmitted in the following order: rotating body 485 provided on the shaft 481f of the support part 520, belt E21, rotating body 621, second hollow shaft 62, and rotating body 622. The rotation of the rotating body 622 drives the belt E22 of the robot wrist 7. The rotating body 621 and belt E21 function as a transmission unit that transmits the rotation of belt E2 to the second hollow shaft 62.

[0086] The third hollow shaft 63 is positioned radially outward of the second hollow shaft 62 via a bearing portion 605d. A rotating body 631 is provided at the upper end 63u of the third hollow shaft 63. A rotating body 632 is provided at the 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 positioned between the rotating body 622 and the rotating body 632 in the Z-axis direction. The rotating body 631 is positioned in the first portion 601, and the rotating body 632 is in the second portion 602 and is positioned within the wrist housing 70. The belt E31 of the third mechanism 53 is stretched over the rotating body 631. The rotation of the belt E3 of the third mechanism 53 is transmitted in the following order: rotating body 515, belt E31, rotating body 631, third hollow shaft 63, and rotating body 632, which are located on the shaft 481f of the support part 530. The rotation of the rotating body 632 drives the belt E32 of the robot wrist 7. The rotating body 631 and belt E31 function as transmission parts that transmit the rotation of belt E3 to the third hollow shaft 63.

[0087] The first hollow shaft 61 is positioned radially outward of the third hollow shaft 63 via a bearing portion 605u. The upper end 61u and lower end 61d of the first hollow shaft 61 are positioned between the upper end 63u and lower end 63d of the third hollow shaft 63 in the Z-axis direction. A rotating body 611 is provided on the upper end 61u of the first hollow shaft 61. The rotating body 611 is positioned on the first portion 601 and rotates integrally with the first hollow shaft 61. The belt E11 of the first mechanism 51 is stretched over 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, belt E11, and rotating body 611, which are provided on the shaft 481f of the support portion 510. The rotating body 611 and belt E11 function as a transmission unit that transmits the rotation of 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 away from the central axis T. The bottom of the tip housing 41 is positioned radially outward of the first hollow shaft 61, between the rotating body 611 and the flange 613 in the Z-axis direction.

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

[0090] In the robot arm 4 described above, the first region Ar1 where the belts 471, E1, E2, and E3 are located and the second region Ar2 where the guide section 45 that guides the extension and retraction of the arm housing 40 is located do not overlap in the Z-axis direction. Therefore, the complexity of assembling the robot arm 4 is suppressed. In addition, interference between the belts 471, E1, E2, and E3 and the guide section 45 is suppressed.

[0091] Furthermore, since the electric motors M, M1, M2, and M3 are positioned at the base end 404, the mass at the free end 405 of the robot arm 4 is reduced. As a result, the operability of the robot arm 4 is improved. In addition, the power required to operate the robot arm 4 is reduced.

[0092] The robot arm 4 has a multi-shaft 6 provided at its free end 405. In the first part 601 of the multi-shaft 6, the rotational power of 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 part 602 of the multi-shaft 6, the rotational power of belts E1, E2, and E3 is output from the first hollow shaft 61, the second hollow shaft 62, and the third hollow shaft 63 to the robot arm 7. Therefore, the complexity of the robot arm 4's configuration is suppressed compared to a configuration in which an input shaft and an output shaft are provided for each belt E1, E2, and E3. Furthermore, the complexity of assembling the robot arm 4 is suppressed. Moreover, it is possible to arrange multiple belts 471, E1, E2, and E3 within the arm housing 40 while suppressing an increase in the size of the robot arm 4.

[0093] In the first region Ar1 of the arm housing 40, the belt E2 and support portion 520 are arranged symmetrically with respect to the virtual plane AP, relative to the belt 471 and support portion 48. Furthermore, belt E1 is positioned directly below belt 471, and belt E3 is positioned directly below belt E2. As a result, the space within the arm housing 40 is effectively utilized. Consequently, the size of the robot arm 4 is kept from increasing.

[0094] Furthermore, the shaft in the support section 48 of the telescopic mechanism 47 is shared with 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 shared with the shaft in the support section 530 of the third mechanism 53. As a result, it is possible to arrange multiple belts 471, E1, E2, and E3 within the arm housing 40 while suppressing an increase in the number of parts constituting the robot arm 4.

[0095] The robot arm 4 is equipped with adjustment sections 54 at the front end 42f of the intermediate housing 42 and the front end 43f of the base 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] Furthermore, the robot arm 4 is equipped with a cable housing 44 located in the third region Ar3 above the belts 471, E1, E2, and E3. This suppresses interference between the cable and the multiple belts. The cable housing 44 is also in communication with the outside at its base end 404. Moreover, the cable housing 44 is in communication with the inside of the second hollow shaft 62 at its free end 405. Therefore, while the cable is placed inside the arm housing 40, interference between the cable and the belts 471, E1, E2, E3, and the guide section 45 can be suppressed. In addition, the cable can be protected compared to a configuration in which the cable is placed outside the robot arm 4.

[0097] <Other embodiments of robotic arms> The arm housing 40 only needs to have a telescopic structure comprising an end housing 41 and a base housing 43, and the number of housings included in the arm housing 40 is not limited to 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, the intermediate housing located in the -X axis direction should be configured to accommodate the intermediate housing located in the +X axis direction so that it can move back and forth.

[0098] The robot arm 4 only needs to include a number of motion mechanisms 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 motion mechanism 50. Alternatively, the robot arm 4 may include four or more motion mechanisms as the motion mechanism 50. For example, further motion mechanisms may be provided below the first mechanism 51 and below the third mechanism 53.

[0099] The multiple shafts of the support section 48 and the multiple shafts of the support section 510 may all be interchangeable. For example, the shaft 483f of the support section 48 may be extended in the Z-axis direction and used as the shaft 512 of the support section 510. In this case, the adjustment section 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 region Ar2 in which the guide section 45 is housed only needs to be different in the Z-axis direction from the region Ar1 in which the belts 471, E1, E2, and E3 are housed. For example, region Ar2 may be positioned above (+Z-axis direction) region Ar1.

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

[0102] <Robot List> Next, the robot wrist 7 will be described using Figures 19 and 21 to 37. The robot wrist 7 is configured to perform a lifting operation that raises and lowers the end effector relative to the robot wrist 7 in the Z-axis direction, and a pitch operation that rotates it around the pitch axis P. In this embodiment, the end effector relative to the robot wrist 7 is a hand 190. The robot wrist 7 mainly comprises a wrist housing 70 extending in the X1 axis direction, a lifting operation unit 8, and a pitch operation unit 9 (see Figure 30). The lifting operation unit 8 includes a belt E22, a second hollow shaft 62 as a drive shaft for driving 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 as a drive shaft for driving the belt E32, a driven shaft 72, and a transmission mechanism 91.

[0103] The lifting mechanism 8 moves the hand 190 (mounting part 191) along the Z-axis direction by moving the mounting part 191 along the Z-axis direction using a link mechanism 80. Figures 22 to 24 show the robot list 7 in the highest position of the mounting part 191. Figures 27 and 28 show the robot list 7 in the lowest position of the mounting part 191. Hereinafter, the highest position of the mounting part 191 will also be called the "highest position," and the lowest position of the mounting part 191 will also be called the "lowest position." The position of the mounting part 191 in the Z-axis direction changes between the highest position and the lowest position. The robot list 7 has a pitch axis P, which is the rotation axis of the mounting part 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 mechanism 9 rotates the hand 190 around the pitch axis P using a transmission mechanism 91.

[0104] In Figure 21 and subsequent figures, the X1 axis direction, Y1 axis direction, and Z axis direction are shown 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 called the forward direction, and the -X1 axis direction is also called the backward direction. The Z axis direction is the direction in which the axis of the multi-shaft 6 extends, and in this embodiment, it is the up and down direction. The +Z axis direction is the upward direction, and the -Z axis direction is the downward direction. The Y1 axis direction is the direction perpendicular to the +X1 axis direction and the Z axis direction. With respect to the robot wrist 7, looking at the robot wrist 7 from the base end 704 in the direction of the +X1 axis direction, the direction to the right is also called the +Y1 axis direction, and the opposite direction is also called the -Y1 axis direction. Note that in Figure 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, but when the robot wrist 7 rotates, the X1 axis direction and the X axis direction are different. Furthermore, in Figure 21, the Y1 axis direction is the same as the Y axis direction, but when the robot wrist 7 rotates, the Y1 axis direction becomes different from the Y axis direction.

[0105] <List 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 direction of extension of the axes T (AX61, AX62, AX63) of the multi-shaft 6. As shown in Figure 21, the wrist housing 70 is attached to the free end 405 of the robot arm 4 at its base end 704. As shown in Figures 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 integrally with the first hollow shaft 61 around the pivot axis T.

[0106] As shown in Figures 23 and 26, the wrist housing 70 is formed as a roughly rectangular parallelepiped with an opening 702 in its lower wall 701d. The lower wall 701d defines the bottom of the wrist housing 70. A portion of the link mechanism 80 is exposed through the opening 702.

[0107] As shown in Figures 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. Sensors for operating the robot 1, such as a distance measuring sensor, camera, and touch sensor, are housed in the sensor housing 706. An opening 705a for the sensors located 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 removable from the partition wall 706b.

[0108] <Internal structure of list housing> Next, the internal configuration of the wrist housing 70 will be described. As shown in Figures 19, 31, and 32, the base end 704 of the wrist housing 70 houses the second hollow shaft 62 and the second portion 602 of the third hollow shaft 63. The third hollow shaft 63 is positioned radially outward of the second hollow shaft 62 via a bearing portion 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 the drive shaft for the lifting mechanism 8. The third hollow shaft 63 functions as the drive shaft for the pitch mechanism 9.

[0109] As shown in Figures 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 retaining member 741 provided around the driven shaft 72. The retaining member 741 is fixed to the partition wall 706b via an adjustment shaft 742. As described above, the driven shaft 72 functions as the driven shaft for the lifting mechanism 8 and the pitch mechanism 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 positions of the rotating body 722 on the driven shaft 72 and the rotating body 622 on the second hollow shaft 62 are approximately the same in the Z-axis direction. A belt E22 for lifting and lowering the wrist is stretched between the two rotating bodies 622 and 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 positions of the rotating body 732 on the driven shaft 72 and the rotating body 632 on the third hollow shaft 63 are approximately the same in the Z-axis direction. A belt E32 for pitch movement is stretched between the two rotating bodies 632.

[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 retaining member 741 via the through hole 706h. By adjusting the amount of protrusion (insertion) of the adjustment shaft 742 into the retaining member 741 by the user, the position of the retaining member 741 in the X1 axis direction is moved. This allows the driven shaft 72 to be moved in the X1 axis direction, thereby adjusting the tension of the belts E22 and E32. The adjustment shaft 742, partition wall 706b (through hole 706h), and retaining member 741 constitute an adjustment section for adjusting 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. Rail 707d is fixed to the lower part of the left and right side walls 701s of the wrist housing 70. Rail 707u is fixed to the upper part of the left side wall 701s of the wrist housing 70. The position of rail 707u in the Z axis direction is approximately equal to that of belt E32. The position of rail 707d in the Z axis direction is approximately equal to that of belt E22. Carriages 806 and 805, which have grooves extending in the X axis direction, are slidably supported on rails 707u and 707d, respectively. Carriages 806 and 805 will be described later.

[0114] <Lifting mechanism> The lifting mechanism 8 will be described using Figures 27 to 34. The lifting mechanism 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 section 81 and a second link section 84. The link mechanism 80 is configured as a Scott-Russell link.

[0116] As shown in Figures 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 extending direction and a second end 815 which is the end opposite to the first end 814 (see Figure 33). In the highest raised position, the first end 814 is located on the base end 704 side of the wrist housing 70. In the highest raised position, the second end 815 is located on the tip end 705 side of the wrist housing 70. As shown in Figure 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 comprises 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 long links in the Scott-Russell link. As shown in Figures 31 and 32, the casing 810 further comprises an upper cover 811c connected to the side walls 811s. The upper cover 811c is omitted in all figures except Figures 31 and 32.

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

[0119] The left retaining block 804 is provided in the -Y1 axis direction of belts E22 and E32. The left retaining block 804 holds the -Y1 axis direction end (left end) of the movable joint shaft 812. The left end of the movable joint shaft 812 holds the left side wall 811s of the casing 810. The left retaining block 804 has an extended portion 804d that extends in the X1 axis direction in its lower part, and protruding portions 804f and 804b that protrude upward from the extended portion 804d. The extended portion 804d is located in the -Y1 axis direction of belt E22. The protruding portions 804f and 804b are located in the -Y1 axis direction of belt E32. The protruding portion 804f protrudes upward from the front end of the extended portion 804d, and the protruding portion 804b protrudes upward from the rear end of the extended portion 804d. The protrusions 804f and 804b are spaced apart in the X1 axis direction.

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

[0121] Furthermore, carriages 805 are fixed to the extensions 804d of the right retaining block 803 and the left retaining block 804, respectively. As described above, the carriages 805 are slidably supported on rails 707d provided on the left and right side walls 801s of the wrist housing 70. The carriages 805 and rails 707d guide the movement of the retaining blocks 803 and 804 in the X1 axis direction. In other words, the carriages 805 and rails 707d guide the movement of the first end 814 and the movable joint shaft 812 in the X1 axis direction.

[0122] The second end 815 of the first link section 81 (casing 810) is provided with a tip joint shaft 822 extending in the Y1 axis direction. Both ends of the tip joint shaft 822 are rotatably 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 section 191 is fixed non-rotatably to the tip joint shaft 822 and rotates integrally with the tip joint shaft 822. The axis AX822 of the tip joint shaft 822 is also the pitch axis P. The second end 815 and the tip joint shaft 822 on the side wall 811s function as the tip joints in the Scott Russell link.

[0123] The second link section 84 functions as a short link in the Scott-Russell link. As shown in Figures 29 and 33, the base end 841 of the second link section 84 is located within the wrist housing 70. The base end 841 is supported by the wrist housing 70 at the tip 705 of the wrist housing 70 by the shaft 843. The connecting end 842 of the second link section 84, opposite to the base end 841, is supported by the side wall 811s of the casing 810 by the shaft 844. The connecting end 842 and the shaft 844 are located approximately midway between the axis AX812 of the movable 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 around the axes AX843 and AX844, respectively. The connecting end 842 and shaft 844 function as the first connecting joint of this disclosure. The base end 841 and shaft 843 function as the second connecting joint of this disclosure.

[0124] As shown in Figure 33, the shaft 843 (axis AX843) at the base end 841 of the second link section 84 is in approximately the same position in the Z-axis direction as the movable joint shaft 812 (axis AX812) of the first link section 81. Furthermore, the movable joint shaft 812 (axis AX812), the shaft 844 (axis AX844) of the second link section 84, and the tip joint shaft 822 (axis AX822) of the first link section 81 are all on the same predetermined straight line. The distance between axes AX843 and AX844, the distance between axes AX844 and AX812, and the distance between axes AX844 and AX822 are all equal.

[0125] The operation of the link mechanism 80 will be explained using Figures 33 and 34. For example, as shown in Figure 33, when the robot wrist 7 is in its 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. The rotation of belt E21 causes the second hollow shaft 62 of the lifting mechanism 8 to rotate, and the belt E22 rotates 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 section 81, and the movable link shaft 812 move in the +X1 axis direction, together with the belt clamp 807 fixed to belt E22. As the movable link shaft 812 moves in the +X1 axis direction, the base end 841 and connecting end 842 of the second link section 84 rotate in the direction of arrow r51 around axes AX843 and AX844, respectively. As a result, the second end 815 and the tip joint shaft 822 of the first link section 81 are moved in the -Z axis direction, and the robot wrist 7 moves to the lowest position shown in Figure 34. The first link section 81 and the second link section 84 are exposed to the outside through the opening 702 of the wrist housing 70 as the first end 814 and the movable joint shaft 812 move in the +X1 axis direction.

[0126] Furthermore, when the robot wrist 7 shown in Figure 34 is in its lowest position, the motor M2 rotates the shaft 22 in the rotation direction r6 shown in Figure 14, causing the belt E2 to rotate in the direction of arrow R6 shown in Figure 34. This causes the second hollow shaft 62 of the lifting mechanism 8 to rotate the belt E22 in the direction of arrow R61, which is opposite to arrow R51. As a result, the left holding block 804, the first end 814 of the first link section 81, and the movable joint shaft 812 move in the -X1 axis direction, together with the belt clamp 807 fixed to the belt E22. Due to the displacement of the first link section 81, the base end 841 and connecting end 842 of the second link section 84 rotate in the direction of arrow r61 around axes AX843 and AX844, respectively. Consequently, the second end 815 of the first link section 81 moves in the +Z axis direction, and the robot wrist 7 moves to the highest position shown in Figure 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 movable joint shaft 812 move in the -X1 axis direction.

[0127] <Pitch movement unit> Next, the pitch operating unit 9 will be described using Figures 29, 30, and 35-37. The pitch operating unit 9 comprises a belt E32, a third hollow shaft 63 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 belt E32 to belt E33. The transmission mechanism 91 includes a movable joint shaft 812 as a drive shaft, a tip joint shaft 822 as a driven shaft, belt E33, a rack gear 921, and a pinion gear 931. In this embodiment, the movable joint shaft 812 included in the movable joint of the link mechanism 80 and the tip joint shaft 822 included in the tip joint are used as the drive shaft and driven shaft of the pitch operation unit 9.

[0129] As shown in Figure 31, a rotating body 912 is provided on the movable link shaft 812. The rotating body 912 is fixed to the movable link shaft 812 and rotates integrally with the movable link shaft 812. A rotating body 922 is provided on the end link shaft 822. The rotating body 922 is fixed to the end link shaft 822 and rotates integrally with the end link shaft 822. The rotating bodies 912 and 922 are toothed pulleys. The belt E33 is stretched between the rotating bodies 912 and 922. As described above, the movable link shaft 812 is provided at the first end 814 of the first link section 81 (casing 810), and the end link shaft 822 is provided at the second end 815 of the first link section 81. The belt E33 is arranged inside the casing 810 and is rotatable within the casing 810. Furthermore, a support shaft and a driven rotating body, which is mounted on the support shaft and supports the rotation of the belt E33, are arranged inside the casing 810.

[0130] As shown in Figures 29, 30, and 35, the rack gear 921 is fixed to a 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 positioned in the X1 axis direction between the protrusions 804f and 804b of the left holding block 804 and is slidably supported on 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, the movement of the rack gear 921 in the +X1 axis direction is restricted by the projection 804f, and the movement of the rack gear 921 in the -X1 axis direction is restricted by the projection 804b. The projections 804f and 804b of the left holding block 804 function as restrictors that restrict the movement of the rack gear 921 in the X1 axis direction. The left holding block 804 supports the movable joint shaft 812 at approximately the midpoint of the extension 804d in the X1 axis direction. Therefore, the rack gear 921 moves along the movable joint shaft 812 in the X1 axis direction.

[0131] The pinion gear 931 is mounted on the movable joint shaft 812 so as to mesh with the rack gear 921. In this embodiment, the pinion gear 931 rotates integrally with the movable joint shaft 812. In this embodiment, the pinion gear 931 is an intermittent gear. The length (circumference) of the gear around the axis AX812 corresponds to the length of the rack gear 921 in the X1 axial direction. In other embodiments, the pinion gear 931 does not have to be an intermittent gear. When the rack gear 921 and the pinion gear 931 mesh, the linear motion of the rack gear 921 in the X1 axial direction is converted into rotational motion of the rotating body 932 on which the pinion gear 931 is mounted, around the axis AX812. The relative displacement of belt E32 and belt E22 in the X1 axial direction is converted into rotational motion of the movable joint shaft 812, which rotates integrally with the pinion gear 931.

[0132] The operation of the transmission mechanism 91 will be explained using Figures 36 and 37. The mounting portion 191 has a mounting surface 192 to which the hand 190, which serves as an end effector, is attached by bolts or the like. In Figure 36, the mounting surface 192 is facing downwards (in the -Z axis direction).

[0133] When motor M3 rotates shaft 23 in rotational direction r7, causing belt E3 to rotate in direction R7 (see Figure 14), in the robot wrist 7 shown in Figure 36, the third hollow shaft 63 of the pitch movement unit 9 rotates 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 motion of the rack gear 921 in the -X1 axis direction is converted into rotational motion of the pinion gear 931 around its axis AX812 in the direction of arrow r72.

[0134] The pinion gear 931 rotates the movable joint shaft 812 in the direction of arrow r72. As a result, the rotating body 912, which is mounted on the movable joint shaft 812 and over which the belt E33 is stretched, rotates in the direction of arrow r72, and the belt E33 rotates in the direction of arrow R72. Due to the rotation of the belt E33, the mounting portion 191 fixed to the end joint shaft 822 rotates (rotates) around the axis AX822 (pitch axis P) in the direction of arrow r72. The mounting surface 192, which was facing in the -Z axis direction, now faces forward (+X1 axis direction), as shown in Figure 37.

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

[0136] The pinion gear 931 rotates the movable joint shaft 812 in the direction of arrow r82. As a result, the rotating body 912, which is mounted on the movable joint shaft 812 and over which the belt E33 is stretched, rotates in the direction of arrow r82, and the belt E33 rotates in the direction of arrow R82, opposite to arrow R72. Due to the rotation of the belt E33, the mounting portion 191 fixed to the end joint shaft 822 rotates (rotates) around the axis AX822 (pitch axis P) in the direction of arrow r82. The mounting surface 192, which was facing forward (+X1 axis direction), now faces downward (-Z axis direction), for example, as shown in Figure 36.

[0137] Furthermore, when the second hollow shaft 62 of the lifting mechanism 8 rotates the belt E22, the pinion gear 931 also moves together with the movable joint shaft 812. As a result, the relative position of the pinion gear 931 and the rack gear 921 changes, and the mounting part 191 may rotate around the pitch axis P. In other words, the pitch movement may be performed in accordance with the lifting movement. In such cases, for example, the robot control device 10 can perform only the lifting movement by controlling the motor M3 to maintain the relative position of the pinion gear 931 and the rack gear 921, in addition to the motor M2 for the lifting movement.

[0138] <Cable housing section> As shown in Figure 26, the bottom wall 811d of the casing 810 includes a first bottom wall 811d1 and a second bottom wall 811d2 that is connected to the first bottom wall 811d1 and formed to project upward. The bottom wall 811d has a stepped shape in the Y1 axis direction. Below the second bottom wall 811d2, a lower cover 813 is positioned. The lower cover 813 is connected to the first bottom wall 811d1 and the side walls 811s. As shown in Figures 31 and 32, the lower cover 813 and the second bottom wall 811d2 define a housing section 809. The housing section 809 is open in the extending direction of the casing 810. The bottom wall 811d and the lower cover 813 function as partition walls that separate the space in the casing 810 in which the belt E33 is housed from the housing section 809.

[0139] In this embodiment, as described above, a multi-shaft 6 is used as the drive shaft for belts E22 and E32. Also, as shown in Figures 8 and 9, the upper end of the multi-shaft 6 is in communication with the cable housing 44 of the robot arm 4. As shown in Figures 31 and 32, the lower end of the multi-shaft 6 is located inside the wrist housing 70. Furthermore, the -X1 axis direction end of the housing section 809 is located inside the wrist housing 70. Therefore, the cable housing 44 in the arm housing 40, the inside of the multi-shaft 6, and the housing section 809 are in communication. Thus, for example, a cable can be routed from the base end 404 of the arm housing 40, through the cable housing 44, the inside of the multi-shaft 6, the lower end of the wrist housing 70, the -X1 axis direction opening of the housing section 809, and the inside of the housing section 809 to the +X1 axis direction opening of the housing space.

[0140] The robot wrist 7 described above comprises a wrist housing 70 having an opening 702 in its lower wall 701d, and a link mechanism 80 that constitutes a Scott-Russell link. The link mechanism 80 has a first link section 81 as a long link and a second link section 84 as a short link. As the movable joint shaft 812 of the first link section 81 moves forward, the mounting section 191 attached to the end joint shaft 822 moves up and down. Therefore, the raising and lowering operation of the mounting section 191 to which the end effector is attached can be performed while suppressing the complexity of the robot wrist 7's configuration. In addition, the movable joint shaft 812 and the first end section 814 are located inside the wrist housing 70, and the base end section 841 (shaft 843) of the second link section 84 is located inside the wrist housing 70 at the tip section 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 movable link shaft 812, and is retracted into the wrist housing 70 through the opening 702 in response to the rearward movement of the movable link shaft 812. This increases the overall rigidity of the robot wrist 7. Furthermore, for example, by moving the movable link shaft 812 in the rearward direction to shorten the vertical length of the robot wrist 7, the robot wrist 7 can be advanced into a region with a relatively narrow vertical length.

[0141] Furthermore, a belt E33 is stretched over the movable joint shaft 812 and the end joint shaft 822 of the link mechanism 80, and the rotational power of belt E32 is transmitted to belt E33 by the transmission mechanism 91, thereby allowing the end joint shaft 822 to rotate around axis AX822 (pitch axis P). In other words, the movable joint shaft 812 and the end joint shaft 822 are used as the drive shaft and driven shaft for pitch movement, respectively, so a drive shaft and driven shaft for executing pitch movement in the robot wrist 7 are not required. As a result, the increase in the number of parts of the robot wrist 7 is suppressed. Consequently, the size of the robot wrist 7 is suppressed. In addition, the increase in the mass of the robot wrist 7 is suppressed.

[0142] Furthermore, the transmission mechanism 91 includes a rack gear 921 fixed to the belt E32 via a belt clamp 808 and moving in the X1 axis direction, and a pinion gear 931 fixed to the movable joint shaft 812. Therefore, the linear motion of the rack gear 921 in the X1 axis direction due to the rotation of the belt E32 can be converted into rotation around the axis of the movable joint shaft 812 via the pinion gear 931. This allows the belt E33 to be rotated and the mounting portion 191 to rotate around the pitch axis P. As a result, the robotic wrist 7 can perform both lifting and pitching movements while suppressing the complexity of the robotic wrist 7's configuration.

[0143] Furthermore, a multi-shaft 6 is used as the drive shaft for belt E22 and the drive shaft for belt E32. In addition, a single driven shaft 72 is used as the driven shaft for belt E22 and the driven shaft for belt E32. Therefore, the complexity of the robot wrist 7 configuration is suppressed. 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. In addition, the belt E33 is placed inside the casing 810. This prevents the belt E33 from interfering with other parts inside the wrist housing 70 or with belts E22 and E32.

[0145] The casing 810 further includes a housing section 809 capable of accommodating cables. The housing section 809 is provided along the extending direction of the casing 810 and is separated from the area within the casing 810 where the belt E33 is positioned. Therefore, interference between the cables housed in the housing section 809 and the belt E33 can be suppressed.

[0146] Furthermore, the wrist housing 70 comprises a front end wall 701f and a partition wall 706b provided behind the front end wall 701f. The front end wall 701f is configured to be removable from the partition wall 706b. The partition wall 706b is provided with a through hole 706h that penetrates in the X1 axis direction (front-rear direction), and an adjustment shaft 742 that can adjust the position of the retaining member 741 that holds the driven shaft 72 in the X1 axis direction is inserted through the through hole 706h. Therefore, by removing the front end wall 701f and adjusting the amount that the adjustment shaft 742 protrudes from the retaining member 741, the tension of the belts E22 and E32 can be adjusted via the driven shaft 72. Moreover, the space defined by the front end wall 701f and the partition wall 706b can be used as a sensor housing section 706.

[0147] <Other embodiments of the robot list> The wrist housing 70 only needs to have an opening 702 in the +Z-axis direction or the -Z-axis direction. The link mechanism 80 only needs to be such that at least a portion is exposed to the outside through the opening 702 when the movable link shaft 812 moves in the +X1-axis direction, and at least a portion is housed inside the wrist housing 70 from the opening 702 when it moves in the -X1-axis direction. For example, the entire link mechanism 80 may be configured to be housed inside the wrist housing 70.

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

[0149] Belts E22, E32, and E33 can be 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 and retraction, wrist rotation, wrist lifting and lowering, and wrist pitching. The arm extension and retraction is the movement in which the arm housing 40 extends and retracts due to the rotation of the belt 471. The wrist rotation is the movement 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 lifting and lowering is the movement in which the belt E2 rotates the second hollow shaft 62, causing the belt E22 inside the wrist housing 70 to rotate and the mounting portion 191 provided at the tip of the link mechanism 80 to lift and lower. The wrist pitch movement is an operation in which the rotation of the third hollow shaft 63 due to the rotation of belt E3 causes belt E32 inside the wrist housing 70 to rotate, changing the relative position of the rack gear 921 and pinion gear 931, which in turn causes belt E33 to rotate and the end joint shaft 822 to rotate around the pitch axis P (the mounting part 191 rotates around the pitch axis P). The movable parts corresponding to the arm extension and retraction movement are, for example, the arm housing 40 and the belt 471 that extends and retracts the arm housing 40. The movable parts corresponding to the wrist rotation movement are, for example, the wrist housing 70 and the first hollow shaft 61 that rotates the wrist housing 70. The movable parts corresponding to the wrist lifting and lowering movement are, for example, the lifting and lowering movement unit 8 (link mechanism 80) and the second hollow shaft 62 included in the lifting and lowering movement unit 8. The movable parts corresponding to the wrist pitch movement are, for example, the pitch movement unit 9 and the third hollow shaft 63 included in the pitch movement unit 9. As a means of transmitting power to each movable part, for example, the drive unit 2n shown in Figure 38 can be considered.

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

[0152] Shaft 200 is directly connected to motor M. Power from shaft 200 is transmitted to shaft 202 via shaft 201, to which a rotary encoder R and torque limiter TL are connected. Specifically, shaft 200 is provided with a rotating body 301 that rotates integrally with shaft 200, and shaft 201 is provided with rotating bodies 302 and 303 that rotate integrally with shaft 201. Furthermore, shaft 202 is provided with rotating bodies 304 and 305 that rotate integrally with shaft 202, and a rotating body 307 that is rotatable relative to shaft 202. The rotation of shaft 200 is transmitted to rotating body 303 via rotating body 301, belt E01, rotating body 302, and shaft 201. The rotation of rotating body 303 is transmitted to rotating body 304 via belt E02. This causes shaft 202 to rotate. When the diameter of the rotating body 304 is 1d, the diameter of the rotating body 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 rotating body 314 that rotates freely relative to shaft 21n and a rotating body 312n that rotates integrally with shaft 21n. Shaft 22n is provided with a rotating body 323n that rotates integrally with shaft 22n and a rotating body 322 that rotates freely relative to shaft 22n. Shaft 23n is provided with a rotating body 333 that rotates freely relative to shaft 23n and a rotating body 331n that rotates integrally with shaft 23n. Rotating bodies 305 and 314 support belt 471. Rotating bodies 307 and 312n are located directly below rotating bodies 305 and 314 and support belt E1. Rotating bodies 323n and 333 support belt E2. Rotating bodies 322 and 331n are positioned directly below rotating bodies 323n and 333 and support belt E3. If the diameter of rotating body 304 is 1d, then the diameters of rotating bodies 305, 314, 312n, 307, 323n, 333, 331n, and 322, which support belts 471, E1, E2, and E3, are 2d.

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

[0155] When the arm housing 40 extends, belt E2, which is positioned symmetrically with respect to belt 471 and the virtual plane AP (see Figure 10), is also forcibly displaced from the free end 405 of the arm housing 40, just like belt E1. This causes the second hollow shaft 62 to rotate, resulting in the robot wrist 7 being raised and lowered. Furthermore, when the arm housing 40 extends, belt E3, which is positioned directly below belt E2 for wrist raising and lowering and is used for wrist pitch movement, is also forcibly displaced from its free end 405. However, since belt E2 is displaced in the same direction as belt E3, the relative positions of the rack gear 921 and pinion gear 931 do not change. Therefore, no wrist pitch movement occurs.

[0156] Thus, if the arm housing 40 is extended by driving only motor M, there is a problem that the robot wrist 7 will rotate and lift. To solve this problem by electrically controlling motors M, M1, M2, and M3, in addition to motor M, motors M1, M2, and M3 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 to belt 471 by the same amount. Column 1 (No. 1) in Figure 39 shows the rotation direction and amount of each belt required when the arm extension operation is performed independently. CCW indicates counterclockwise rotation, CW indicates clockwise rotation, and ×1, ×2, etc., indicate the amount of rotation. For example, CCW×1 indicates rotation in the counterclockwise direction with an amount of rotation of 1. The numbers ×1, ×2, etc., represent the ratio of the amount of rotation (displacement) in each belt.

[0157] For example, to rotate the robot wrist 7 counterclockwise, when motor M1 is driven and shaft 21n rotates counterclockwise by an amount of 1, the rotating body 312n rotates counterclockwise by an amount of 1, and belt E1 is displaced by that amount of rotation. As a result, the wrist housing 70 rotates. At this time, 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 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 extending in the X1 axis direction in the wrist housing 70. As a result, belt E21 (see Figure 13) inside the wrist housing 70 is displaced, causing the robot wrist 7 to move up and down. Furthermore, although belt E31 inside the wrist housing 70 is displaced by the phase difference described above, just like belt E21, since belts E31 and E21 are displaced simultaneously in the same direction, the relative positions of the rack gear 921 and pinion gear 931 do not change. Therefore, no wrist pitch movement occurs.

[0158] Thus, if we attempt to rotate the robot wrist 7 by driving only motor M1, there is a problem in that the robot wrist 7 will also perform an upward or downward movement. 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 out the displacement of belts E21 and E31 inside the wrist housing 70. Specifically, as shown in No. 3 and No. 4 of Figure 39, it is necessary to rotate belts E2 and E3 in the same rotational direction and by the same amount as belt E1.

[0159] Furthermore, for example, if the motor M2 is rotated counterclockwise by an amount of 1 to raise the robot wrist 7 (mounting part 191), the rotating body 323n also rotates counterclockwise by an amount of 1, and the belt E2 is displaced by that amount of rotation. As a result, the belt E21 is displaced, and the wrist lifting and lowering operation is performed. At this time, the shafts 200, 201, 202, 21n, and 23n of the drive unit 2n do not rotate. However, the rotation of belt E2 displaces belt E21 inside the wrist housing 70, causing the pinion gear 931 to move together with the moving joint shaft 812. Therefore, the relative position of the rack gear 921 and the pinion gear 931 changes. As a result, a wrist pitch operation is performed in the robot wrist 7.

[0160] Thus, if we attempt to raise and lower the robot wrist 7 by driving only motor M2, there is a problem in that the robot wrist 7 will also perform pitch movement. 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 within the wrist housing 70. Specifically, as shown in No. 5 and No. 6 of Figure 39, in order to displace belt E31 by the same amount and in the same direction as belt E21, it is necessary to rotate belt E3 by the same amount and in the same rotational direction as belt E2.

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

[0162] Figure 39 shows the rotation direction and amount of each belt required to perform each of the following operations independently: (No.1) arm extension, (No.2) arm contraction, (No.3) wrist rotation (counterclockwise), (No.4) wrist rotation (clockwise), (No.5) wrist raising, (No.6) wrist lowering, (No.7) wrist pitch movement (r72 direction, see Figure 37), and (No.8) wrist pitch movement (r82 direction, see Figure 36). As described above, when the drive unit 2n is applied to the robot 1, it is also possible to perform each of the operations (No.1) to (No.8) independently by inputting displacement commands to motors M, M1, M2, and M3 and driving each motor. However, such electrical control requires a complex algorithm. Therefore, it may lead to problems such as increased processing load in the robot control device 10 and control device 101, increased power consumption, and decreased responsiveness of each movable part.

[0163] Therefore, in this embodiment, the control mechanism 20 solves at least some of the above problems. The control mechanism 20 is a mechanical mechanism configured to operate the first movable part and the second movable part independently in a structure having a plurality of movable parts, including a first movable part and a second movable part that is in a dependent relationship with the first movable part. Below, first, using Figures 40 to 43, the operation of the second movable part due to the operation of the first movable part (dependent relationship) in a reference example structure 150n that does not have a control mechanism will be explained. Next, using Figures 44 to 51, the operation of the dependent relationship in a structure 150 equipped with the control mechanism 20a will be explained.

[0164] As shown in Figure 40, the structure 150n comprises a first housing 133, a second housing 147, a first motor 131, a first shaft 132n which is the output shaft of the first motor 131, a second motor 141, and a second shaft 142n which is the output shaft of the second motor 141. The first housing 133 is a first movable part connected to the first shaft 132n and pivoting around the axis ax1 of the first shaft 132n.

[0165] Inside the first housing 133 are 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 stretched between the rotating bodies 143n and 144n. One end of the shaft 146 protrudes from the first housing 133 and this end is fixed to the second housing 147. The second housing 147 is a second movable part that pivots around the axis ax3 of the shaft 146. When the second shaft 142n rotates, the belt 145 rotates, causing the rotating body 144n and the shaft 146 to rotate together. As a result, the second housing 147 pivots around the axis ax3.

[0166] Figures 41 to 43 will be used to explain the operation of the entire structure 150n when the first housing 133 is rotated. The dashed line 133s shown in Figure 41 is the central axis of the first housing 133.

[0167] In the initial state shown in Figure 41, when the first motor 131 is driven and the first shaft 132n is rotated, the first housing 133 pivots around axis ax1. At this time, the second motor 141 is not driven, so the rotating bodies 143n and 144n do not rotate. Therefore, as a result of the pivoting of the first housing 133, the relative positional relationship between the first housing 133 and the second housing 147 changes, as shown in Figure 42, and the second housing 147 pivots relative 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 Figure 41 and to pivot only the first housing 133, it is necessary to drive the second motor 141 to rotate the rotating body 144n and shaft 146 in the same direction of rotation as the first shaft 132n and by the same amount of rotation (rotation angle). For example, if the first housing 133 (first shaft 132n) rotates (swivels) by 30° in the direction of arrow r91 around axis ax1 shown in Figure 41, it is necessary to drive the second motor 141 to rotate the rotating body 144n and shaft 146 by 30° in the direction of arrow r92 around axis ax3 shown in Figure 42. This allows only the first housing 133 to swivel while maintaining the positional relationship between the first housing 133 and the second housing 147 in their initial state, as shown in Figure 43.

[0168] Thus, 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] Figure 44 is a schematic diagram showing a structure 150 having a control mechanism 20. The control mechanism 20 includes a correction unit 17 which consists of a differential gear 160 and a reduction unit 170. First, the differential gear 160 will be described using Figures 45 to 49.

[0170] Figure 45 shows an example of a differential gear 160. The differential gear 160 shown in Figure 45 is a ball differential. The differential gear 160 has a first differential shaft 161 and a second differential shaft 162 extending in a predetermined direction, and a rotating body 163. In Figure 45, the predetermined direction is shown as the Z-axis direction. The axes ax4 of the first differential shaft 161 and the second differential shaft 162 extend in the Z-axis direction.

[0171] The rotating body 163 has a plurality of housings 164 that house steel balls (hereinafter referred to as balls 165). The rotating body 163 and the balls 165 are collectively referred to simply as the rotating body or retainer pulley. The first differential shaft 161 has a flange 161f to which a slide plate 161p is attached. The flange 161f contacts 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 contacts 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 pivotally supported by a shaft member 166 so as to be rotatable around the axis ax4.

[0172] The operation of the differential gear 160 will be explained using Figures 46 to 49. Figure 46 shows a ball 165 with diameter D, and a first differential shaft 161 and a second differential shaft 162 that clamp the ball 165. Note that in Figures 46 and subsequent figures and explanations, 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 its initial state, and the lower part of Figure 46 shows the differential gear 160 after the first differential shaft 161 has rotated from the initial state. A fixed state is a state in which the shaft or rotating body in question is stopped. A fixed state is a state in which the shaft or rotating body in question does not displace even if an external force is applied to it. For example, when a motor movably connected to a shaft or a motor movably 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] As shown in Figure 46, when the first differential shaft 161 rotates from its initial state, the ball 165 in contact with the first differential shaft 161 also rotates. When the amount of movement (rotation) of the first differential shaft 161 is Dθ, the rotation angle of the ball 165 in contact with the first differential shaft 161 is θ. Since the rotating body 163 is fixed, the second differential shaft 162, which is in contact with the ball 165, moves in the opposite direction to the first differential shaft 161 by an amount of movement Dθ due to the rotation of the ball 165. As a result, as shown in Figure 47, when power is input to the first differential shaft 161 and the first differential shaft 161 rotates around axis ax4 by an amount of rotation (angular velocity) ω, the second differential shaft 162 rotates in the opposite direction to the first differential shaft 161 by an amount of rotation ω. Similarly, when rotational power is input to the second differential shaft 162 and the second differential shaft 162 rotates around axis ax4 by an amount ω, the first differential shaft 161 rotates in the opposite direction to the second differential shaft 162 by an amount ω.

[0174] Next, we will explain the case where one of the first differential shaft 161 and the second differential shaft 162 is fixed, using Figure 48. The upper part of Figure 48 shows the differential gear 160 in its initial state when the second differential shaft 162 is fixed, and the lower part of Figure 48 shows the differential gear 160 after the ball 165 has rotated from the initial state. As shown in Figure 48, when the second differential shaft 162 is fixed and the first differential shaft 161 and the rotating body 163 are not fixed, when the ball 165 rotates on the second differential shaft 162 at a rotation angle θ, the ball 165 moves on the second differential shaft 162 by a displacement amount Dθ. At this time, the first differential shaft 161, which is in contact with the ball 165, moves further by a displacement amount Dθ due to the rotation of the ball 165. Therefore, the total displacement of the first differential shaft 161 from its initial position is 2Dθ. In other words, the amount of rotation of the first differential shaft 161 is twice the amount of rotation of the rotating body 163 having the ball 165. The amount of rotation of the rotating body 163 can also be said to be half that of the first differential shaft 161.

[0175] Although not shown in the diagram, even when the first differential shaft 161 is fixed and the second differential shaft 162 and the rotating body 163 are not fixed, if the ball 165 rotates on the first differential shaft 161 at a rotation angle θ, the total displacement of the second differential shaft 162 from its initial position will be 2Dθ. In other words, the amount of rotation of the second differential shaft 162 is twice the amount of rotation of the rotating body 163 containing the ball 165. It can also be said that the amount of rotation of the rotating body 163 is half that of the second differential shaft 162.

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

[0177] Returning to Figure 44, the structure 150 will be described. In the structure 150, the first shaft 132, which outputs power from the first motor 131, and the second shaft 142, which outputs power from the second motor 141, are each formed integrally with the flange. The first motor 131 and the second motor 141 are servo motors with a servo lock function. Between the first shaft 132 and the second shaft 142, a rotating body 163 is positioned as a retainer pulley incorporated into a ball differential. The first shaft 132, the second shaft 142, and the rotating body 163 constitute the differential gear 160. The first shaft 132 functions as the first differential shaft of the differential gear 160 and as the first drive shaft that outputs power to rotate the first housing 133. The second shaft 142 functions as the second differential shaft of the differential gear 160 and as the second drive shaft that outputs power to rotate the second housing 147.

[0178] Belt 145 is stretched between rotating body 163 and rotating body 144. The diameter of rotating body 144 is half the diameter of rotating body 139. Therefore, the rotational speed of rotating body 144 is twice the rotational speed of rotating body 163. Rotating body 163, rotating body 144, and belt 145 constitute a reduction unit (speed conversion unit) 170. The other configurations of structure 150 are the same as those of structure 150n in the comparative example.

[0179] The differential gear 160 and the reduction gear 170 are provided in the connecting section CP, which is the power transmission path between the first shaft 132 and the second shaft 142. The connecting section CP is the part that operably connects the first shaft 132 and the second shaft 142. The differential gear 160 and the reduction gear 170 are also called the correction section 17. The correction section 17 corrects the operation (driven relationship) of the second housing 147 caused by the operation of the first housing 133. The first shaft 132, the second shaft 142, the differential gear 160, and the correction section 17 constitute the control mechanism 20a.

[0180] The operation of the entire structure 150 when the first housing 133 is rotated will be explained using Figures 50 and 51. To rotate the first housing 133 30° around axis ax1 from the initial state shown in Figure 50, first the first motor 131 is driven to rotate the first shaft 132 (see Figure 44) 30° in the direction of arrow r9 shown in Figure 50. Driving the motor means that the control device 101 or robot control device 10 inputs a displacement command to the motor. At this time, the second motor 141 is in a servo-on state, that is, it is under power control and exhibiting 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 rotating body 163 of the differential 160 rotates by half the amount of rotation of the first shaft 132, or 15°. Also, since the diameter of the rotating body 144 is half the diameter of the rotating body 139, the rotation angle of the rotating body 144 is twice the rotation angle of the rotating body 139. Therefore, the rotating body 144 rotates by 30°. As a result, as shown in Figure 51, the first housing 133 is rotated by 30°, and the relative positional relationship between the first housing 133 and the second housing 147 is maintained at the positional relationship in the initial state shown in Figure 50. Alternatively, by fixing the first shaft 132 and driving the second motor 141 to rotate the second shaft 142 by a desired amount, only the second housing 147 can be rotated around the axis ax3.

[0182] As explained above, by applying the control mechanism 20a to the structure 150, the first housing 133 can be rotated around axis ax1 using 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 axis ax3 using 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 mutually dependent on each other, each movable part can be operated independently by a mechanical mechanism, without relying on electrical control to control the displacement of multiple motors. Consequently, in a structure with multiple degrees of freedom, each degree of freedom can be operated independently while avoiding an increase in processing load in 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 robot wrist 7 will be described. Figure 52 schematically shows the power transmission path from the drive unit 2 provided at the base end 404 of the robot arm 4 to each movable part. Figure 52 shows the drive pulley and the retainer pulley incorporated into the differential, which are among the multiple rotating bodies of the drive unit 2 shown in Figure 20. In Figure 52 and subsequent figures, the driven pulley is omitted from the rotating bodies. First, the configuration of the drive unit 2 of this embodiment will be specifically described using Figures 20 and 52. The drive unit 2 comprises 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 wrist pitch movement, a shaft 200, 201, 202, 21, 22, 23, and a plurality of rotating bodies.

[0184] As shown in Figure 20, the shaft 202 is provided with rotating bodies 304, 305, 306, and 307 in the direction of the -Z axis, that is, from top to bottom, in this order. The rotating bodies 304, 305, and 307 rotate integrally with the shaft 202. Rotating body 307 is rotatable relative to the shaft 202. Rotating body 307 is omitted in Figure 52. The diameter of rotating body 304 is 1d, and the diameters of rotating bodies 304, 305, and 307 are 2d.

[0185] As shown in Figure 20, the shaft 21 is provided with rotating bodies 315, 314, 313, 312, and 311 in that order from top to bottom. Rotating body 312 is a retainer pulley. As shown in Figure 52, the shaft 21 includes shaft 212 located above the rotating body 312 and shaft 211 located below the rotating body 312. Although not shown in Figure 20, shafts 212 and 211 each have flanges that contact the steel balls of the rotating body 312 via plates. This is also true for the shafts located above and below the retainer pulleys on shafts 22 and 23. Shaft 212, rotating body 312, and shaft 211 constitute the first differential gear 160a. Rotating bodies 315, 314, and 313 are provided on shaft 212. Rotating bodies 315 and 313 rotate integrally with the shaft 212, while rotating body 314 is rotatable relative to the shaft 211. Rotating body 314 is omitted in Figure 52. Rotating body 311 is mounted on the shaft 211 and rotates integrally with the 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) mounted on the shaft 22.

[0186] As shown in Figure 20, the shaft 22 is provided with rotating bodies 324, 323, 322, and 321 in that order from top to bottom. Rotating bodies 323 and 321 are retainer pulleys. As shown in Figure 52, the shaft 22 includes shafts 223, 222, and 221. Shaft 223 is positioned above rotating body 323, and shaft 222 is positioned between rotating body 323 and rotating body 321. Shaft 221 is positioned below rotating body 321. Shaft 223, rotating body 323, and shaft 222 constitute the second differential gear 160b. Also, shafts 222, shaft 221, and rotating body 321 constitute the third differential gear 160c. In other words, shaft 222 is a differential shaft that is used for both the second differential gear 160b and the third differential gear 160c.

[0187] Rotating body 322 is mounted on shaft 222 and is rotatable relative to shaft 222. Rotating body 322 is omitted in Figure 52. The diameters of rotating bodies 323, 322, and 321 are 2d. Rotating body 324 is a spur gear mounted on shaft 223 and rotates integrally with shaft 223.

[0188] As shown in Figure 20, the shaft 23 is provided with rotating bodies 333, 332, and 331 in that order from top to bottom. Rotating body 331 is a retainer pulley. As shown in Figure 52, the shaft 23 includes shaft 232 positioned above rotating body 331 and shaft 231 positioned below rotating body 331. Shaft 232, rotating body 331, and shaft 231 constitute the fourth differential gear 160d. Rotating bodies 333 and 332 are provided on shaft 232. Rotating body 333 is rotatable relative to shaft 232. Rotating body 333 is omitted in Figure 52. Rotating body 332 rotates integrally with shaft 232. The diameters of rotating bodies 333 and 331 are 2d, and the diameter of rotating body 332 is 1d.

[0189] As shown in Figure 20, shafts 202 and 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 Figure 20, shafts 22 (shaft 223) and 23 (shaft 232) support belts E2 and E3. Specifically, belt E2 is supported by rotating bodies 323 and 333, as shown in Figure 20. Belt E3 is supported below belt E2 by rotating bodies 322 and 331. Belt E05 is stretched between rotating bodies 323 and 332 in the Z-axis direction between belts E2 and E3. Belt E04 is stretched between rotating body 311 on shaft 21 and rotating body 321 on shaft 22.

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

[0192] Belt E04 is stretched between two rotating bodies 311 and 321, which have different diameters. The rotating bodies 311 and 321 and belt E04 constitute the second reduction unit 172. The second reduction unit 172 connects a shaft 211 that transmits power from motor M1 to belt E1 and a shaft 22 that transmits power from motor M2 to belt E2.

[0193] Belt E05 is stretched between two rotating bodies 323 and 332, which have different diameters. The rotating bodies 323 and 332 and belt E05 constitute the third reduction unit 173. The third reduction unit 173 connects a shaft 222 that transmits power from motor M2 to belt E2 and a shaft 231 that transmits power from motor M3 to belt E3.

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

[0195] Furthermore, the first reduction unit 171, together with the second differential 160b, constitutes the second correction unit A2. The second correction unit A2 is provided in the power transmission path between shaft 202 and shaft 22. The second correction unit A2 converts the power output from motor M to shaft 202 using the first reduction unit 171 and inputs it to the second differential 160b, which rotates belt E2. This corrects the rotation of belt E2 caused by the expansion and contraction of arm housing 40.

[0196] The second reduction unit 172 and the third differential gear 160c are located in the power transmission path between the shaft 21 and the shaft 22. The second reduction unit 172 and the third differential gear 160c constitute the 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 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 unit 173 and the fourth differential gear 160d are located in the power transmission path between shaft 22 and shaft 23. The third reduction unit 173 and the fourth differential gear 160d constitute the fourth correction unit A4. The fourth correction unit A4 converts the power output from motor M2 to shafts 221 and 222, and the power output from motors M and M1 to shaft 223, using the third reduction unit 173, and inputs it to the fourth differential gear 160d, causing belt E3 to rotate. This corrects the rotation of belt E33 caused by the wrist lifting operation via belt E32.

[0198] Figures 53 to 56 will be used to specifically explain how the movable parts corresponding to each motor operate independently when motors M, M1, M2, and M3 are driven individually. The movable parts corresponding to motor M for arm extension and retraction are the arm housing 40 and the belt 471 that extends and retracts the arm housing 40. The movable parts corresponding to motor M1 for wrist rotation are the wrist housing 70 and the first hollow shaft 61 that rotates the wrist housing 70. The movable parts corresponding to motor M2 for wrist lifting and lowering are the lifting and lowering mechanism 8 (link mechanism 80) and the second hollow shaft 62 included in the lifting and lowering mechanism 8. The movable parts corresponding to motor M3 for wrist pitching are the pitching mechanism 9 and the third hollow shaft 63 included in the pitching mechanism 9. In Figures 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. Furthermore, the power transmission paths from motors M, M1, M2, and M3 are indicated by dashed arrows. In the diagram, motors with a slash ( / ) indicate that they are in a servo-locked state, and parts with a slash indicate that they are in a fixed state.

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

[0200] When motor M is driven and shaft 200 rotates counterclockwise with a rotation amount of 1 (CCW × 1), the rotational power of shaft 200 is transmitted to rotating body 304 via rotating body 301, belt E01, rotating body 302, shaft 201, rotating body 303, and belt E02. Rotating body 304 and shaft 202 rotate counterclockwise with a rotation amount of 1 (CCW × 1). As a result, rotating body 305 rotates counterclockwise with a rotation amount of 1 (CCW × 1) together with shaft 202, and belt 471 is displaced counterclockwise with a rotation amount of 1 (CCW × 1).

[0201] Furthermore, the rotating body 306 rotates integrally with the shaft 202 (CCW x 1), power is transmitted to the rotating body 313 via the belt E03, and the rotating body 313 rotates 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 unit 171, the rotating body 313 and the shaft 212 rotate counterclockwise with a rotation amount of 2 (CCW x 2).

[0202] The rotation of shaft 212 (CCW x 2) is input to the rotating body 312, which is a retainer pulley. Since shaft 211, which constitutes the first differential gear 160a, is fixed, the input from shaft 212 causes the rotating body 312 to rotate counterclockwise by an amount of rotation 1 (CCW x 1). As a result, power of an amount of rotation 1 in a counterclockwise direction is transmitted to belt E1 (CCW x 1). Consequently, the displacement of belt E1 due to the stretching of belt 471 is canceled (see Figure 39, No. 1), and belt E1 for lifting and lowering the wrist does not rotate. In other words, the displacement of belt E1 is canceled by the first correction unit A1, which includes the first reduction 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 direction of rotation of shaft 212 is converted by spur gears 315 and 324, causing shaft 223 to rotate clockwise by an amount of 2 (CW×2). Since shaft 222, which constitutes the second differential 160b, is fixed, the rotating body 323 rotates clockwise by an amount of 1 (CW×1). As a result, power of an amount of 1 rotation clockwise is transmitted to belt E2 (CW×1). Therefore, the displacement of belt E2 due to the extension of belt 471 (arm housing 40) is canceled (see Figure 39, No. 1). 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 extension of belt 471 is canceled, and belt E2 for wrist pitch movement does not displace. In other words, the second correction unit A2, which includes the first reduction unit 171 and the second differential gear 160b, cancels out the displacement of belt E2 when belt 471 is driven.

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

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

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

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

[0208] Furthermore, the rotation of the rotating body 311, which rotates integrally with the shaft 211 (CCW x 2), is transmitted to the rotating body 321, which is a retainer pulley, via the belt E04. Due to the difference in diameter between the rotating body 311 and the rotating body 321 that constitute the second reduction unit 172, the rotating body 321 rotates counterclockwise with a rotation amount of 1 (CCW x 1). Since the shaft 221 that constitutes the third differential 160c is fixed, the rotation of the rotating body 321 causes the shaft 222 to rotate counterclockwise with a rotation amount of 2 (CCW x 2). In addition, since the shaft 223 that constitutes the second differential 160b is fixed, the rotation of the shaft 222 (CCW x 2) causes the rotating body 323 to rotate counterclockwise with a rotation amount of 1 (CCW x 1). As a result, power with a rotation amount of 1 in a counterclockwise direction is transmitted to the belt E2 (CCW x 1). Therefore, the displacement of the belt E22 inside the wrist housing 70 due to the rotation of the robot wrist 7 is canceled out. In other words, the displacement of the belt E22 is canceled out by the third correction unit A3, which includes the second reduction unit 172 and the third differential 160c.

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

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

[0211] Figure 55 shows the power transmission path from motor M2 to each part when raising the mounting portion 191 of the robot wrist 7. For example, when a command to raise the wrist housing 70 is input from the control device 101 to the robot control device 10, the robot control device 10 inputs the displacement amount corresponding to the raising command to motor M2 and drives motor M2. Note that motors M, M1, M3 and the shafts and rotating bodies driven by them are in a fixed state. Note that when the wrist raising operation is performed independently, each belt needs to 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 rotation 2 (CW × 2), the rotating body 321 constituting the third differential 160c is fixed, so the input from shaft 221 causes shaft 222 to rotate counterclockwise by an amount of rotation 2 (CCW × 2). The shaft 223 constituting the second differential 160b is also fixed, so the rotation of shaft 222 causes the rotating body 323 to rotate counterclockwise by an amount of rotation 1 (CCW × 1). As a result, belt E2 is displaced by an amount of rotation 1 counterclockwise (CCW × 1). Consequently, belt E22 is displaced in the direction of arrow R61 shown in Figure 34.

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

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

[0215] Figure 56 shows the power transmission path from motor M3 to each part when the mounting portion 191 of the robot wrist 7 is pitched. For example, when a wrist pitch movement command is input from control device 101 to robot control device 10, the robot control device 10 inputs the displacement amount corresponding to the pitch movement command to motor M3 and drives motor M3. Note that motors M, M1, 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, which constitutes the fourth differential 160d, is fixed. Therefore, the input from shaft 231 causes the rotating body 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). Consequently, belt E32 is driven via belt E31, and a wrist pitch operation is performed.

[0217] As described above, the motor M3 alone can independently perform a wrist pitch motion that rotates the hand 190 in a rotational direction r72 around axis P. Furthermore, by rotating the shaft 231 clockwise by an amount of 2 using the motor M3, the motor M3 can independently perform a wrist pitch motion that rotates the hand 190 in a rotational direction r82 around axis P.

[0218] As explained above, the drive unit 2 is equipped with a control mechanism 20, which allows each movable part corresponding to motors M, M1, M2, and M3 to be operated independently. Therefore, compared to a configuration in which each movable part is operated independently by electrically controlling motors M, M1, M2, and M3, the increase in processing load on the robot control device 10 and control device 101 can be suppressed. In addition, since each movable part can be operated independently by driving only the motor corresponding to that movable part, the power consumption of motors M, M1, M2, and M3 can be suppressed. Furthermore, since complex algorithms for operating each movable part independently are not required, the responsiveness of each movable part can be improved.

[0219] Furthermore, since the differentials 160, 160a, 160b, 160c, and 160d are ball differentials, the complexity of the control mechanisms 20a and 20 can be suppressed. Therefore, the drive unit 2, which includes the control mechanism 20, can be placed at the base end 404 of the robot arm 4.

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

[0221] In the above embodiment, motors 131, 141, M, M1, M2, and M3 drove shafts 132, 142, 202, 21, 22, and 23, which served as drive shafts. However, these shafts 132, 142, 202, 21, 22, and 23 are not limited to motors; they can be driven by any external force.

[0222] In the above embodiment, the servo lock mechanism of the servo motor was used to fix the shaft and rotating body in the differential gear. However, the shaft and rotating body may be fixed by other external forces, not limited to the servo lock function.

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

[0224] Robot List 7 is an example of a "robot list". List housing 70 is an example of a "housing". The X1 axis direction is an example of the "first direction". The +X1 axis direction is an example of the "forward direction". The -X1 axis direction is an example of the "backward direction". The Z-axis direction is an example of a "second direction." The Y1-axis direction is an example of a "third direction." The base portion 704 is an example of a "housing base portion". The tip portion 705 is an example of a "housing tip portion". The lower wall 701d is an example of a "bottom section". The opening 702 is an example of an "opening". The second hollow shaft 62 is an example of the "first drive shaft". The driven shaft 72 is an example of a "first driven shaft". Belt E22 is an example of a "first endless member". Link mechanism 80 is an example of a "link mechanism". The first link section 81 is an example of the "first link section". The movable joint shaft 812 and the first end portion 814 are examples of a "movable joint". Hand 190 is an example of an "end effector". Mounting part 191 is an example of a "mounting part". The second end portion 815 and the tip section shaft 822 are examples of "tip sections". The second link section 84 is an example of a "second link section". The connecting end 842 and shaft 844 are examples of the "first connecting section". The base portion 841 and shaft 843 are examples of a "second connecting node". The movable segment shaft 812 is an example of a "movable segment shaft". The tip section shaft 822 is an example of a "tip section shaft". The pitch axis P and axis line AX822 are examples of "axis of the tip joint shaft". The third hollow shaft 63 is an example of a "second drive shaft". The driven shaft 72 is an example of a "second driven shaft". Belt E32 is an example of a "second endless member". The transmission mechanism 91 is an example of a "transmission mechanism". Rack gear 921 is an example of a "rack gear". Pinion gear 931 is an example of a "pinion gear". Multiple shaft 6 is an example of a "multiple shaft" design. The second hollow shaft 62 and the third hollow shaft 63 are "multiple hollow shafts" Casing 810 is an example of a "casing". The side wall 811s is an example of a "side wall". The bottom wall 811d is an example of a "bottom wall". The bottom wall 811d and the lower cover 813 are examples of "partition walls". Storage section 809 is an example of a "storage section". The partition wall 706b, through hole 706h, retaining member 741, and adjustment shaft 742 are examples of the "adjustment section". Through-hole 706h is an example of a "through-hole". Partition wall 706b is an example of a "tip wall". Adjustable shaft 742 is an example of an "adjustable shaft". The sensor housing section 706 is an example of a "sensor housing section". The left retaining block 804 is an example of the "first retaining part". The carriage 805, belt clamp 808, and block member 808m are examples of the "second holding part". The extended portion 804d, the protruding portion 804f, and the protruding portion 804b are examples of the "extended portion," "front protruding portion," and "rear protruding portion," respectively. Robot arm 4 and robot 1 are examples of "robot arm" and "robot."

[0225] This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. For example, this disclosure can also be implemented in the following forms (aspects). The technical features in the embodiments described above that correspond to the technical features in each of the forms described below can be replaced or combined as appropriate in order to solve some or all of the problems of this disclosure, or to achieve some or all of the effects of this disclosure. Furthermore, if such technical features are not described as essential in this specification, they can be deleted as appropriate.

[0226] <1> A robotic list is provided according to a first embodiment of the present disclosure. The robotic list comprises a housing extending in a first direction, a first drive shaft, a first driven shaft, a first endless member, and a linkage mechanism. The housing comprises a housing base portion and a housing tip portion. The housing tip portion is provided on the opposite side of the housing base portion in the first direction. The housing has a bottom portion in a second direction intersecting the first direction. The bottom portion is provided with an opening. The first drive shaft is provided at the housing base portion and extends in the second direction. The first driven shaft is provided at the housing tip portion and extends in the second direction. The first endless member is stretched between the first drive shaft and the first driven shaft. The first endless member rotates within the housing by the rotational power of the first drive shaft. The linkage mechanism comprises a first link portion and a second link portion, constituting a Scott-Russell link. The first link portion comprises a movable link and a tip link. A mounting portion is connected to the tip section. The mounting portion is configured to allow the attachment of an end effector. The second link section comprises a first connecting section and a second connecting section. The first connecting section is rotatably connected to the first link section between the movable section and the tip section. The second connecting section is rotatably connected to the housing at the front end of the housing. The movable section is configured to move in a first direction within the housing by the rotation of the first endless member. The tip section is configured to move in a second direction in response to the movement of the movable section in the first direction. At least a portion of the link mechanism is configured to be exposed to the outside of the housing in response to the movement of the movable section in the forward direction from the base end of the housing to the front end of the housing in the first direction. At least a portion of the link mechanism is configured to be housed inside the housing through the opening in response to the movement of the movable section in the rearward direction opposite to the forward direction. In this embodiment, if the direction in which the tip joint shaft moves away from the housing in the second direction is defined as downward, and the direction opposite to the downward direction is defined as upward, the tip joint may be configured to move downward in accordance with the forward movement of the movable joint. The tip joint may also be configured to move upward in accordance with the rearward movement of the movable joint. This configuration allows the mounting section connected to the end joint to be moved in a second direction with a relatively simple structure. Furthermore, as the movable joint moves, at least a portion of the link mechanism is housed within the housing, increasing the overall rigidity of the robot list. Moreover, by moving the movable joint in the first direction, the second-direction length of the robot list can be shortened, allowing the robot list to be deployed into relatively narrow spaces. Therefore, it is possible to provide a robot list that can reach a wide range of end effectors attached to the mounting section and deploy into relatively narrow spaces while suppressing complexity and size.

[0227] <2> the above <1> In the robot list described herein, the movable joint may include a movable joint shaft extending in a third direction intersecting the first and second directions. The end joint may include an end joint shaft extending in the third direction. The robot list may further include a third endless member stretched between the movable joint shaft and the end joint shaft, and rotating by the rotation of the movable joint shaft. The end joint shaft may be configured to be rotated by the third endless member. The mounting portion may be fixed to the end joint shaft and configured to rotate integrally with the end joint shaft about the axis of the end joint shaft. In this configuration, the mounting portion can be rotated around the axis of the tip joint shaft by rotating the tip joint shaft with the third endless member. Therefore, it is possible to move the end effector attached to the mounting portion in the second direction and rotate it around the axis of the tip joint shaft.

[0228] <3> the above <2> In the robot list described herein, the robot list may include a second drive shaft, a second driven shaft, a second endless member, and a transmission mechanism. The second drive shaft is provided at the base end of the housing and extends in the second direction. The second driven shaft is provided at the tip of the housing and extends in the second direction. The second endless member is stretched between the second drive shaft and the second driven shaft and rotates within the housing by the rotational power of the second drive shaft. The transmission mechanism is configured to transmit the rotation of the second endless member to the third endless member. In this configuration, the linear force of the second endless member in the first direction is converted into rotation of the third endless member by the transmission mechanism, allowing the tip joint shaft to rotate around its axis.

[0229] <4> the above <3> In the robot list described herein, the transmission mechanism may include a rack gear and a pinion gear. The rack gear may be configured to move integrally with the second endless member in the first direction. The pinion gear may be fixed to the movable joint shaft and configured to mesh with the rack gear. The pinion gear may be configured to rotate the movable joint shaft as the rack gear moves in the first direction. In this configuration, the output of the second drive shaft is converted into rotation of the movable joint shaft via the second endless member, rack gear, and pinion gear. Furthermore, the rotation of the movable joint shaft causes the third endless member to rotate, which in turn causes the end joint shaft to rotate. Therefore, the linear power of the second endless member is converted into rotation of the end joint shaft using the rack gear and pinion gear, and the mounting part connected to the end joint shaft can be rotated (whether) around the axis of the end joint shaft.

[0230] <5> the above <3> or <4> In the robot list described above, the first drive shaft and the second drive shaft may be configured as a multi-shaft. The multi-shaft may comprise a plurality of hollow shafts arranged coaxially. The plurality of hollow shafts may be configured such that their diameters and lengths in the second direction differ from each other. In this configuration, the first and second endless members can each be rotated using multiple shafts. This reduces the number of parts in the robotic arm. Furthermore, compared to a configuration in which the first and second drive shafts are provided as separate components on different axes in the housing, the robotic arm can be made smaller.

[0231] <6> the above <2> from <5> In any of the robot lists described herein, the first link portion may include a casing. The casing may comprise a pair of side walls and a bottom wall. The pair of side walls may include a side wall connected to one end of the movable link shaft in the third direction and a side wall connected to the other end. The bottom wall may be connected to the pair of side walls. The casing may communicate with the housing. The third endless member may be located within the casing. In this configuration, the movable parts of the robotic list are located within the housing or casing. This allows for increased rigidity of the entire robotic list.

[0232] <7> the above <6> In the robot list described herein, the casing may include a housing section. The housing section may extend in the direction from the movable joint shaft toward the tip joint shaft. The housing section may be partitioned by a partition wall from the area in which the third endless member is housed. The housing section may be formed such that both ends in the extending direction of the housing section are open. According to this embodiment, an attachment portion is connected to the tip shaft of the first link portion. Further, the first link portion includes a casing in which a third endless member is accommodated, and the casing includes an accommodation portion formed along the moving joint shaft to the tip joint shaft. The inside of the casing communicates with the inside of the housing, and openings are provided at both ends in the extending direction within the accommodation portion. Therefore, a cable connected to a sensor or the like provided in the end effector can reach from the base end portion of the housing to the end effector through the accommodation portion. Accordingly, interference between the cable and the third endless member, components within the housing, and an object outside the robot list is suppressed.

[0233] <8> The robot list according to any one of <1> to <7> above may further include an adjustment portion provided at the tip end portion of the housing. The adjustment portion may be configured to adjust the tension of the first endless member. The adjustment portion may include a tip wall and an adjustment shaft. The tip wall may include a through hole penetrating in the first direction. The tip wall may be positioned in the forward direction with respect to the first driven shaft. The adjustment shaft may be configured to be inserted through the through hole and protrude into the housing. The adjustment shaft may be configured to adjust the position of the first driven shaft in the first direction. According to this embodiment, the tension of the first endless member can be adjusted using the adjustment shaft at the tip end portion of the housing. Therefore, the robot list can be easily maintained.

[0234] <9> In the robot list according to any one of <1> to <8> above, the housing may include a sensor accommodation portion provided at the tip end portion of the housing in the forward direction with respect to the first driven shaft. According to this embodiment, a sensor can be accommodated at the tip end portion of the housing.

[0235] <10> the above <4> The robot list described herein may include a first holding portion for holding the end of the movable joint shaft and a second holding portion for holding the rack gear. The first holding portion may have an extending portion fixed to the first endless member and extending in a first direction, a front projection portion projecting from the extending portion in a second direction, and a rear projection portion spaced apart from the front projection portion in the first direction and projecting from the extending portion in a second direction in the rear direction of the front projection portion. The second holding portion may be fixed to the second endless member and positioned between the front projection portion and the rear projection portion in the first direction. In this configuration, the second retaining portion moves between the front and rear protrusions, thereby suppressing excessive movement of the rack gear in the first direction. Furthermore, by setting the distance between the front and rear protrusions in the first direction to a desired distance, the rotation range of the mounting portion can be set to a desired range. Therefore, for example, interference between the mounting portion and the housing due to excessive rotation of the mounting portion can be suppressed.

[0236] <11> According to the second form of this disclosure, <1> from <10> A robot is provided that has a robot list as described in any of the above. This configuration provides a robot equipped with a robot list that can expand the range of motion of the end effector while suppressing increased complexity and size of the configuration.

[0237] <12> the above <11> In this configuration, the robot may further include a robot arm to which the base end of the housing of the robot list is attached, and which outputs power to the robot list. In this configuration, the robot arm may have a telescopic housing. In this configuration, the robotic arm can be used to further expand the range of motion of the end effector. [Explanation of Symbols]

[0238] 1: Robot, 10: Robot control device, 11: Cart, 12: Lifting device, 15: Imaging device, 100: Robot system, 101: Control device, 110: Main body, 111: Top surface, 112: Recess, 120: Support column, 190: Hand, 191: Mounting part, 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 body, E01,E02,E03,E04,E05: Belt, 160a: First differential gear, 160b: Second differential gear, 160c: Third differential gear, 160d: Fourth differential gear, 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 A 40: Arm housing, 401, 402, 403: Upper wall, 404: Base end, 405: Free end, AP: Virtual plane, AX: Central axis, 41: Tip housing, 41b: Rear end of tip housing, 411: Extension, 412: Projection, 42: Intermediate housing, 42b: Rear end of intermediate housing, 42f: Front end of intermediate housing, 421: Extension, 422, 423: Projection, 43: Base housing, 43f: Front end of base housing, 431: Extension, 432, 433: Projection Part, 44: Cable housing, 441: Tip housing, 441s: Tip, 442: Intermediate housing, 443: Base housing, 443s: Rear end, 45: Guide part, 451, 452: Carriage, 451g, 452g: Groove, 454, 455: Rail, Ar1: First area, Ar2: Second area, Ar3: Third area, 47: Telescopic mechanism, 471: Belt, 472: Belt clamp, 473: Drive unit, 48: Support part, 481f, 481b, 481c, 482f, 482b, 482c, 482f,483f: Shaft, 485: Rotating body, 6: Multi-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: Rotating body, 613: Flange, 62: Second hollow shaft, 62d: Lower end of second hollow shaft, 62u: Upper end of second hollow shaft, 621, 622: Rotating body, 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 housing, 704: Base end, 705: Tip end, 706: Sensor housing, 705a: Opening, 706b: Partition wall, 706h: Through hole, 707d, 707u: Rail, 72: Driven shaft, 722, 732: Rotating body, 741: Holding member, 742: Adjustment shaft, 8 : Lifting mechanism, 80: Link mechanism, 81: First link section, 812: Moving joint shaft, 814: First end, 815: Second end, 821: Rack gear, 822: Tip joint shaft, 84: Second link section, 841: Base end, 842: Connecting end, 843, 844: Shaft, 801s: Side wall, 803, 804: Holding block, 804b, 804f: Protruding part, 804d: Extending part, 805, 806: Carriage, 807, 808: Belt clamp, 808m: Block member, 809: Housing section, 810: Case 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 part, 516, 526, 536: Drive part, 511, 512: Shaft, 54: Adjustment part, 541: Holding part, 542: Recess, 544: Hole, 545: Front end wall, 546: Through hole, 548: Adjustment shaft, 9: Pitch operating part, 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 the 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 part, 20a: Control mechanism, 160: Differential gear, 161 :First differential shaft, 162:Second differential shaft, 161f,162f:Flange, 161p,162p:Slide plate, 163:Rotating body, 164:Housing part, 165:Ball, 166:Shaft member, 170:Reduction unit, D:Diameter, Dθ:Amount of movement, θ:Rotation angle, ω:Amount of rotation, 150n:Structure of comparative example, 132n:First shaft, 142n:Second shaft, 143n:Rotating body, 144n:Rotating body, 2n:Drive unit of comparative example, 21n,2 2n, 23n: Shaft, 312n, 323n, 331n: Rotating body, E1, E11, E2, E21, E22, E3, E31, E32, E33: Belt, AX202, AX21, AX22, AX23, AX61, AX62, AX63, AX72, AX812, AX822, AX843, AX844, ax1, ax2, ax3, ax4: Center axis, ax1, ax2, ax3, ax4: Center axis, P: Pitch axis, T: Swivel axis, H: Work axis Pace, C1: 1st container, C2: 2nd 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: lifting axis, V: forward / backward axis, W: workpiece, r1, r2, r3, r4, r5, r51, r6, r61, r7, r72, r8, r82, r9, r91, r92: rotation direction,

Claims

1. It is a robot list, A housing extending in a first direction, having a base end of the housing and a front end of the housing opposite to the base end of the housing in the first direction, and having an opening at the bottom in a second direction intersecting the first direction, A first drive shaft provided at the base end of the housing and extending in the second direction, A first driven shaft provided at the tip of the housing and extending in the second direction, A first endless member is stretched between the first drive shaft and the first driven shaft, and rotates within the housing by the rotational power of the first drive shaft, A linkage mechanism, A first link section comprising a movable section and a tip section to which a mounting section to which an end effector can be attached is connected, A link mechanism comprising a Scott-Russell link includes a second link section comprising a first connecting link rotatably connected to the first link section between the moving link and the tip link, and a second connecting link rotatably connected to the housing at the tip of the housing, The movable joint moves within the housing in the first direction by the rotation of the first endless member. The tip section moves in the second direction in response to the movement of the movable section in the first direction. At least a portion of the link mechanism is exposed to the outside of the housing in response to movement of the movable link in the first direction, specifically in the forward direction from the base end of the housing to the front end of the housing, and is retracted into the inside of the housing through the opening in response to movement of the movable link in the rearward direction opposite to the forward direction. Robot list.

2. A robot list according to claim 1, The movable joint includes a movable joint shaft extending in a third direction intersecting the first and second directions, The aforementioned end section includes an end section shaft extending in the third direction, The robot list further includes a third endless member that is stretched between the movable joint shaft and the end joint shaft and rotates as the movable joint shaft rotates, The aforementioned end section shaft is rotated by the third endless member, The mounting portion is fixed to the tip joint shaft and rotates integrally with the tip joint shaft around the axis of the tip joint shaft, in a robotic wrist.

3. A robot list according to claim 2, A second drive shaft provided at the base end of the housing and extending in the second direction, A second driven shaft provided at the tip of the housing and extending in the second direction, A second endless member is stretched between the second drive shaft and the second driven shaft, and rotates within the housing by the rotational power of the second drive shaft, A robotic wristband comprising a transmission mechanism for transmitting the rotation of the second endless member to the third endless member.

4. A robot list according to claim 3, The aforementioned transmission mechanism is A rack gear that is movable in the first direction integrally with the second endless member, A robotic arm comprising: a pinion gear fixed to the movable joint shaft and meshing with the rack gear, the pinion gear rotating the movable joint shaft by the movement of the rack gear in the first direction.

5. A robot list according to claim 3, The robotic arm is configured such that the first drive shaft and the second drive shaft are a multi-shaft system in which a plurality of hollow shafts with different diameters and lengths in the second direction are arranged coaxially.

6. A robot list according to claim 2, The first link portion comprises a pair of side walls connected to both ends of the movable link shaft, and a bottom wall connected to the pair of side walls, and includes a casing that communicates with the inside of the housing. The third endless member is a robotic wrist, which is located inside the casing.

7. A robot list according to claim 6, The casing extends in the direction from the movable joint shaft to the tip joint shaft, is partitioned by a partition wall from a region where the third endless member is housed, and has a housing portion with both ends in the extending direction being open.

8. A robot list according to claim 1, further, An adjustment section provided at the tip of the housing, It has a through hole that penetrates in the first direction, and a tip wall that is located in the forward direction relative to the first driven shaft, A robotic wristband is provided with an adjustment section, which includes an adjustment shaft inserted through the through hole and protruding into the housing, and which adjusts the position of the first driven shaft in a first direction.

9. A robot list according to claim 1, The robotic wrist has a housing that includes a sensor housing portion provided at the tip of the housing in a direction forward of the first driven shaft.

10. A robot list according to claim 4, A first holding portion that holds the end of the movable joint shaft, It comprises a second holding part for holding the rack gear, The first holding portion has an extending portion fixed to the first endless member and extending in a first direction, a front projection portion projecting from the extending portion in a second direction, and a rear projection portion spaced apart from the front projection portion in the first direction and projecting from the extending portion in a second direction in the rear direction of the front projection portion. The second holding portion is fixed to the second endless member and is positioned between the front projection and the rear projection in the first direction, and is a robotic wrist.

11. A robot comprising the robot list described in claim 1.

12. The robot according to claim 11, Furthermore, the robot includes a robot arm to which the base end of the housing of the robot list is attached, and which outputs power to the robot list.

Images