Hand device

Abstract

Provided is a hand device that can grip various objects with different dimensions and can obtain sufficient gripping force. 【Solution means】The hand device (310) includes a first gripping claw (320A), a second gripping claw (320B) that faces the first gripping claw (320A) with a gap therebetween and grips an object together with the first gripping claw (320A), and a motor (340). The first driving mechanism (351) slides at least one of the gripping claws (320), i.e., the first gripping claw (320A) and / or the second gripping claw (320B), using the output from the motor (340) as a driving force. The hand device (310) also includes an air-type piston cylinder (330). The second driving mechanism (352) slides at least one of the gripping claws (320), i.e., the first gripping claw (320A) and / or the second gripping claw (320B), using the output from the piston cylinder (330) as a driving force.

Description

Technical Field

[0001] This invention relates to a hand device.

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2017-102825 (Patent Document 1) discloses a composite system including a machine tool having a work fixing jig movable integrally with a table, a work stocker for storing a work, and a robot system having a robot that supplies and removes the work between the work fixing jig and the work stocker. The robot is provided with a robot hand for gripping the work to be handled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As disclosed in the above Patent Document 1, a hand device having a pair of gripping claws for gripping an object such as a work is known. In such a hand device, it is required to enhance the versatility of the hand device by enabling gripping of various objects having different dimensions. Also, in order to prevent the object from falling from the hand device, it is required to ensure sufficient gripping force.

[0005] An object of this invention is to provide a hand device capable of gripping various objects having different dimensions and capable of obtaining sufficient gripping force.

Means for Solving the Problems

[0006] The hand device according to the present invention includes a first gripping claw, a second gripping claw that faces the first gripping claw at a distance and grips an object together with the first gripping claw, a motor, and uses the output from the motor as a driving force to slide at least one of the first gripping claw and the second gripping claw. A first drive mechanism, an air-type piston cylinder, and a second drive mechanism that uses the output from the piston cylinder as a driving force to slide at least one of the first gripping claw and the second gripping claw.

Effect of the Invention

[0007] According to the present invention, it is possible to provide a hand device that can grip various objects with different dimensions and can obtain sufficient gripping force.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Embodiments of this invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are given the same numbers.

[0010] FIG. 1 is a top view showing a transport system. FIG. 2 is a top view showing a simplified transport system in FIG. 1.

[0011] Referring to FIGS. 1 and 2, the transport system 100 has a robot 21 and a robot base 22.

[0012] As a typical example, the robot 21 is a 6-axis articulated robot. The robot 21 has a base portion 26, a first arm 27, a second arm 28, a hand attachment portion 29, and a master hand 210.

[0013] The robot base 22 is a support base that supports the robot 21 and is fixed to the floor surface of a factory or the like. The robot base 22 is made of metal. The base portion 26 is connected to the robot base 22 so as to be rotatable about the turning center axis 101. The turning center axis 101 is a virtual straight line corresponding to the turning center of the robot 21 and extends in the vertical direction.

[0014] The first arm 27 is attached to the base portion 26. The first arm 27 is rotatable about a rotation center axis 102 disposed at the attachment portion (joint portion) of the first arm 27 to the base portion 26. The second arm 28 is attached to the first arm 27. The second arm 28 is rotatable about a rotation center axis 103 disposed at the attachment portion (joint portion) of the second arm 28 to the first arm 27, and the hand attachment portion 29 can be rotated about a rotation center axis 104 along the second arm 28. The hand attachment portion 29 is attached to the second arm 28. The hand attachment portion 29 is rotatable about a rotation center axis 105 disposed at the attachment portion (joint portion) of the hand attachment portion 29 to the second arm 28, and the master hand 210 can be rotated about a rotation center axis 106 along the hand attachment portion 29.

[0015] The master hand 210 is attached to the hand attachment portion 29 as an end effector. The master hand 210 is attached to the second arm 28 so as to be rotatable about the rotation center axis 105. The master hand 210 is attached to the second arm 28 via the hand attachment portion 29. The second arm 28 is attached to the first arm 27 so as to be rotatable about the rotation center axis 103.

[0016] The robot 21 further includes a base portion 26, a first arm 27, a second arm 28, a hand attachment portion 29, and a master hand 210, and a plurality of drive servo motors 23 for operating them respectively around the plurality of axes (swivel center axis 101, pivot center axis 102, pivot center axis 103, rotation center axis 104, pivot center axis 105, and rotation center axis 106) (see FIG. 9 described later).

[0017] In FIG. 1, an area (operation area of the master hand 210) where the master hand 210 moves in the transfer system 100 is shown by a two-dot chain line 111. Also, a maximum area where the master hand 210 can move is shown by a two-dot chain line 112 extending in an arc around the swivel center axis 101.

[0018] The transfer system 100 further includes a machine tool 10 (10S, 10T), pallet stockers 31 (31S, 31T), a work stocker 71, a hand stocker 81, and setup stations 61 (61S, 61T).

[0019] The machine tool 10 (10S, 10T), pallet stockers 31 (31S, 31T), work stocker 71, hand stocker 81, and setup stations 61 (61S, 61T) are provided around the robot base 22. The machine tool 10 (10S, 10T), pallet stockers 31 (31S, 31T), work stocker 71, hand stocker 81, and setup stations 61 (61S, 61T) are arranged along the circumferential direction of the swivel center axis 101. In the top view shown in FIG. 1, at least a part of each of the devices of the machine tool 10 (10S, 10T), pallet stockers 31 (31S, 31T), work stocker 71, hand stocker 81, and setup stations 61 (61S, 61T) overlaps the operation area of the master hand 210 indicated by the two-dot chain line 111.

[0020] Note that the robot in the present invention is not limited to the above-described 6-axis articulated robot. For example, it may be a robot (gantry loader) capable of moving an object to be transported in three axial directions orthogonal to each other. Further, the machine tool, pallet stocker, work stocker, hand stocker, and setup station may be arranged side by side in a straight line.

[0021] The machine tool 10 is a machining center that performs workpiece machining by bringing a rotating tool into contact with the workpiece. The machine tool 10 is an NC (Numerically Controlled) machine tool in which various operations for workpiece machining are automated by numerical control by a computer.

[0022] The machine tool 10 may be a composite machining machine having a turning function using a fixed tool and a milling function using a rotating tool, or may be an AM / SM hybrid machining machine capable of additive manufacturing of a workpiece and subtractive manufacturing of the workpiece. The machine tools 10S and 10T may be the same type of machine tool as each other, or may be different types of machine tools from each other.

[0023] The machine tool 10 has a cover body 14. The cover body 14 forms the appearance of the machine tool 10 and partitions and forms a machining area 12. The machining area 12 is a space where workpiece machining is performed, and is sealed by the cover body 14 so that foreign substances such as chips or cutting oil accompanying workpiece machining do not leak outside the machining area.

[0024] The cover body 14 is provided with an opening 16. The robot 21 transports an object to be transported such as the workpiece W or the pallet 410 to the machining area 12 through the opening 16. The opening 16 is provided with a door or shutter capable of opening and closing operations.

[0025] The machining area 12 is provided with a tool spindle for rotating a tool and a table for holding the pallet 410, etc.

[0026] The machine tool 10 further has an operation panel 18. The operation panel 18 includes a control device for controlling the operation of the machine tool 10, a display unit (display) for displaying various information related to machining, and an operation unit for receiving various operations on the machine tool 10.

[0027] The machine tools 10S and 10T are provided at positions facing each other with the robot base 22 therebetween. The machine tools 10S and 10T are provided at angular positions shifted by 180° in the circumferential direction centered on the turning center axis 101.

[0028] The pallet stocker 31 is a device for storing the pallet 410. The pallet stocker 31 is provided between the machine tools 10S and 10T in the circumferential direction centered on the turning center axis 101. The pallet stockers 31S and 31T are provided adjacent to each other in the circumferential direction centered on the turning center axis 101.

[0029] The work stocker 71 is a device for storing the work W. The work stocker 71 has a shelf structure on which the work W can be placed. The hand stocker 81 is a device for storing various hands such as the work hand 310 and the teaching hand 710 described later. The hand stocker 81 has a shelf structure on which various hands can be placed.

[0030] The work stocker 71 and the hand stocker 81 are provided between the machine tools 10S and 10T in the circumferential direction centered on the turning center axis 101. The work stocker 71 and the hand stocker 81 are provided at positions facing the pallet stocker 31 (31S, 31T) with the robot base 22 therebetween. The work stocker 71 and the hand stocker 81 are provided one above the other.

[0031] The setup station 61 is mainly a device for attaching and detaching the workpiece W to and from the pallet 410. A pallet mounting table (not shown) on which the pallet 410 can be placed is installed at the setup station 61. The setup station 61 is provided between the workpiece stocker 71 and the hand stocker 81 and the machine tool 10 in the circumferential direction centered on the turning center axis 101. The setup station 61 is provided adjacent to the workpiece stocker 71 and the hand stocker 81 in the circumferential direction centered on the turning center axis 101.

[0032] The setup stations 61S and 61T are provided on both sides of the workpiece stocker 71 and the hand stocker 81 in the circumferential direction centered on the turning center axis 101.

[0033] Note that the number of each device of the machine tool 10, the pallet stocker 31, the workpiece stocker 71, the hand stocker 81, and the setup station 61 provided in the transport system 100 is not particularly limited.

[0034] The transport system 100 further has a plurality of fences 56 (56h, 56i, 56j, 56k). The fences 56 rise from the floor surface of a factory or the like. In the top view shown in FIG. 1, the fence 56h extends between the machine tool 10S and the pallet stocker 31S. In the top view shown in FIG. 1, the fence 56i extends between the pallet stocker 31T and the machine tool 10T. In the top view shown in FIG. 1, the fence 56j extends between the machine tool 10T and the setup station 61T. In the top view shown in FIG. 1, the fence 56k extends between the setup station 61S and the machine tool 10S.

[0035] The robot 21 is disposed in a space 113 surrounded by a plurality of fences 56 (56h, 56i, 56j, 56k), machine tools 10 (10S, 10T), pallet stockers 31 (31S, 31T), a work stocker 71, a hand stocker 81, and setup stations 61 (61S, 61T). The operating area of the master hand 210 indicated by the dashed two-dot line 111 is included in the space 113.

[0036] An operator cannot access the pallet stocker 31 from the outside of the space 113. The operator can load a pallet 410 into the pallet stocker 31 or retrieve the pallet 410 from the pallet stocker 31 through the setup station 61. The operator can access the work stocker 71 and the hand stocker 81 from the outside of the space 113. The operator can load an unprocessed work W into the transport system 100 or retrieve a processed work W' from the transport system 100 through the work stocker 71. The operator can load various hands into the transport system 100 or retrieve the various hands from the transport system 100 through the hand stocker 81.

[0037] The transport system 100 further includes an operation panel 51 for transport. The operation panel 51 for transport includes a control device 610 that controls the operation of the robot 21, a display unit 670 for displaying various information related to the transport by the robot 21, and an operation unit that receives various operations for the robot 21 (see FIG. 9 to be described later). In the present embodiment, the display unit 670 is configured by a touch panel display operable by an operator and undertakes part of the functions of the operation unit. The operation unit may be composed of various buttons that can be pressed, numeric keys for inputting numbers, or dials or the like.

[0038] The operation panel 51 for transport is attached to the work stocker 71 and the hand stocker 81. The position where the operation panel 51 for transport is provided is not particularly limited.

[0039] FIG. 3 is a perspective view showing the relationship among the pallet, the work hand, the shelf board, and the teaching hand with respect to the master hand. FIGS. 4 and 5 are perspective views showing the master hand. FIG. 6 is a view for explaining the structure of the master hand.

[0040] Referring to FIGS. 3 to 6, the master hand 210 has a clamp mechanism 220. The clamp mechanism 220 is configured to be operable between a clamped state for holding the gripping portion 120 and an unclamped state for releasing the gripping portion 120.

[0041] As shown in FIGS. 4 to 6, the gripping portion 120 has a grip shape centered on the central axis 126. The gripping portion 120 is provided with a groove portion 121. The groove portion 121 is recessed from the outer peripheral surface of the gripping portion 120 and has a groove shape that circulates around the central axis 126.

[0042] The clamp mechanism 220 has the appearance of a block body. The clamp mechanism 220 is provided with a grip insertion hole 221. The grip insertion hole 221 is open in one direction.

[0043] The clamp mechanism 220 consists of a cylinder piston. The clamp mechanism 220 has a pair of pistons 226. The pair of pistons 226 extend in a shaft shape along a central axis 231 that is orthogonal to the central axis 126 and intersects the grip insertion hole 221. The pair of pistons 226 face each other with a space therebetween in the axial direction of the central axis 231. The pair of pistons 226 are slidably supported in the axial direction of the central axis 126. At the tip of each piston 226, a protrusion 227 that can engage with the groove portion 121 is provided.

[0044] When the master hand 210 grips the gripping part 120, the master hand 210 is positioned so that the clamp mechanism 220 faces the gripping part 120. By linearly moving the master hand 210 in a direction approaching the gripping part 120, the gripping part 120 is inserted into the grip insertion hole 221. By supplying air pressure or the like and slidingly moving the pair of pistons 226 in a direction approaching each other, the clamp mechanism 220 is operated from the unclamped state to the clamped state. Thereby, the protruding portions 227 of the pair of pistons 226 project into the grip insertion hole 221 and engage with the groove portion 121.

[0045] When the master hand 210 releases the gripping part 120, the clamp mechanism 220 is operated from the clamped state to the unclamped state by slidingly moving the pair of pistons 226 in a direction moving away from each other. Thereby, the protruding portions 227 of the pair of pistons 226 withdraw from the grip insertion hole 221 and disengage from the groove portion 121. By linearly moving the master hand 210 in a direction moving away from the gripping part 120, the gripping part 120 is removed from the grip insertion hole 221.

[0046] As shown in FIG. 5, the conveying system 100 further includes a sensor 230. The sensor 230 is a sensor capable of detecting the presence or absence of an object, and as an example, is a non-contact photoelectric sensor. The sensor 230 may be a proximity sensor or a contact sensor such as a limit switch.

[0047] The sensor 230 is mounted on the robot 21. The sensor 230 is mounted on the master hand 210. When the sensor 230 is a photoelectric sensor, the emission direction of the light from the sensor 230 may be parallel to the advancing and retracting direction of the gripping part 120 with respect to the master hand 210.

[0048] Referring to FIG. 3, the conveying system 100 further includes a pallet 410 for holding a workpiece. The conveying system 100 has a plurality of pallets 410.

[0049] The pallet 410 is made of a metal plate material and has a substantially rectangular shape when viewed from above. The table provided in the machine tool 10 incorporates a clamp mechanism for gripping the pallet 410. Fixtures such as an ikele or a clamping device are attached to the pallet 410, and a workpiece is held on the pallet 410 via the fixture.

[0050] The pallet 410 has a first gripping portion 120A. The first gripping portion 120A corresponds to the above-described gripping portion 120 and is configured to be grippable by the master hand 210. The first gripping portion 120A is provided on the side surface of the pallet 410. The first gripping portion 120A is detachably provided with respect to the pallet 410.

[0051] When the master hand 210 grips the first gripping portion 120A, the robot 21 can transport the pallet 410.

[0052] FIG. 7 is a perspective view showing the pallet stocker in FIG. 1. FIG. 8 is a perspective view showing the pallet stocker in the range surrounded by the two-dot chain line VIII in FIG. 7.

[0053] In FIGS. 7 and 8, and in other figures showing the pallet stocker 31, the X-axis, Y-axis, and Z-axis, which are the coordinate axes in the pallet stocker 31, are shown. The X-axis extends in a horizontal direction corresponding to the width direction (left-right direction) of the pallet stocker 31, the Y-axis extends in the vertical direction, and the Z-axis extends in a horizontal direction corresponding to the depth direction (front-rear direction) of the pallet stocker 31. The X-axis, Y-axis, and Z-axis are three mutually orthogonal axes.

[0054] Referring to FIGS. 3, 7, and 8, the pallet stocker 31 has a frame body 550, a plurality of support portions 560, and a plurality of shelf plates 510.

[0055] The frame body 550 forms a rectangular parallelepiped-shaped frame. The frame body 550 forms a rectangular parallelepiped-shaped frame in which each direction in the X-axis direction and the Y-axis direction is the longitudinal direction and the Z-axis direction is the short side direction. The frame body 550 has four columns 551. The four columns 551 are arranged at the four corners of the frame body 550 in a top view. Each column 551 extends in the Y-axis direction (vertical direction).

[0056] The support portion 560 is configured to be able to support the shelf board 510. A plurality of support portions 560 are arranged at intervals in the vertical direction.

[0057] The support portion 560 has a pair of plates 561 on the left and right. The pair of plates 561 are provided at intervals in the X-axis direction. The plate 561 has an L-shaped cross-sectional shape when cut by the X-axis - Y-axis plane and extends in the Z-axis direction. Both ends of the plate 561 in the Z-axis direction are respectively connected to two columns 551 arranged in the Z-axis direction.

[0058] The shelf board 510 is configured to be able to place the pallet 410. The shelf board 510 has a rectangular shape in a top view in which the X-axis direction is the longitudinal direction and the Z-axis direction is the short side direction, and has a plate shape in which the Y-axis direction is the thickness direction.

[0059] The shelf board 510 has a pair of vertical frames 532 on the left and right and a pair of horizontal frames 531 in the front and back. The pair of vertical frames 532 are provided at intervals in the X-axis direction. The pair of vertical frames 532 are respectively provided at both ends of the shelf board 510 in the X-axis direction. The vertical frame 532 is made of a plate material in which the Y-axis direction is the thickness direction and extends in the Z-axis direction. The pair of horizontal frames 531 are provided at intervals in the Z-axis direction. The horizontal frame 531 extends in the X-axis direction and is respectively connected to the pair of vertical frames 532 at both ends thereof.

[0060] As shown in FIGS. 7 and 8, the shelf board 510 is supported by the support portion 560. The pair of vertical frames 532 are placed on the pair of plates 561. The pair of vertical frames 532 bear the weight of the shelf board 510.

[0061] As shown in FIG. 8, the support portion 560 further has a pin 562. The pin 562 is provided on the plate 561. The pin 562 protrudes upward from the top surface of the plate 561. A pin hole 533 is provided in the vertical frame 532. The pin hole 533 is a through hole that penetrates the vertical frame 532 in the Y-axis direction. The pin 562 is disposed in the pin hole 533. With such a configuration, displacement of the shelf board 510 with respect to the support portion 560 is prevented.

[0062] As shown in FIG. 3, the shelf board 510 further has a plurality of pallet support portions 520 (520p, 520q, 520r).

[0063] Each pallet support portion 520 is configured to be able to support the pallet 410. Each pallet support portion 520 is composed of four tapered cone receivers 525 that are arranged at intervals in the X-axis direction and the Z-axis direction. The tapered cone receivers 525 are provided on the horizontal frame 531. The tapered cone receivers 525 protrude upward from the top surface of the horizontal frame 531. The tapered cone receivers 525 have a concave shape capable of receiving the tapered cone provided on the bottom surface of the pallet 410.

[0064] The pallet support portion 520p, the pallet support portion 520q, and the pallet support portion 520r are arranged in the X-axis direction in the order listed.

[0065] The shelf board 510 is compatible with the placement of pallets 410 of different sizes. For example, the shelf board 510 is compatible with the placement of a pallet 410 of size 400 mm × 400 mm and the placement of a pallet 410 of size 500 mm × 500 mm. When the pallet 410 is of size 400 mm × 400 mm, three pallets 410 can be placed on the shelf board 510 using the pallet support parts 520p, 520q, and 520r. When the pallet 410 is of size 500 mm × 500 mm, two pallets 410 can be placed on the shelf board 510 using the pallet support parts 520p and 520r.

[0066] As shown in FIGS. 3 and 7, the shelf board 510 has a second gripping part 120B. The second gripping part 120B corresponds to the above-described gripping part 120 and is configured to be grippable by the master hand 210. The second gripping part 120B is provided at the center position of the shelf board 510 in the X-axis direction. The second gripping part 120B protrudes in the Z-axis direction from the front surface of the shelf board 510 (horizontal frame 531). The second gripping part 120B is provided below the pallet support part 520 (taper cone receiver 525). The second gripping part 120B is detachably provided with respect to the shelf board 510.

[0067] By the master hand 210 gripping the second gripping part 120B, the robot 21 can convey the shelf board 510. The robot 21 performs position replacement of the shelf board 510 among a plurality of support parts 560 in the pallet stocker 31.

[0068] As shown in FIG. 7, the pallet stocker 31 further has a fixed shelf board 515. The fixed shelf board 515 basically has the same structure as the shelf board 510, but is different from the shelf board 510 in that the second gripping part 120B is not provided. The fixed shelf board 515 cannot be position-replaced among the plurality of support parts 560, and its position in the pallet stocker 31 is fixed.

[0069] The pallet stocker 31 has two fixed shelves 515. The two fixed shelves 515 are respectively arranged at the uppermost and lowermost levels in the pallet stocker 31. The shelf 510 can be repositioned within the vertical range between the fixed shelf 515 arranged at the uppermost level and the fixed shelf 515 arranged at the lowermost level.

[0070] Referring to FIG. 3, the work hand 310 is configured to be able to grip the work W. The work hand 310 has a pair of gripping claws 320. The pair of gripping claws 320 face each other with a space therebetween.

[0071] The work hand 310 is operably configured between a clamped state in which the work W is gripped by the pair of gripping claws 320 and an unclamped state in which the pair of gripping claws 320 releases the work W. By sliding the pair of gripping claws 320 in a direction approaching each other, the work hand 310 operates from the unclamped state to the clamped state. By sliding the pair of gripping claws 320 in a direction moving away from each other, the work hand 310 operates from the clamped state to the unclamped state.

[0072] The work hand 310 has a piston cylinder 330 and a servo motor 340 as power sources for sliding the pair of gripping claws 320 (see FIGS. 9 and 24 to be described later). The structure of the work hand 310 will be described in detail later.

[0073] The work hand 310 further has a third gripping portion 120C. The third gripping portion 120C corresponds to the above-described gripping portion 120 and is configured to be grippable by the master hand 210. The third gripping portion 120C has a grip shape extending in a direction orthogonal to the sliding direction of the pair of gripping claws 320. The third gripping portion 120C is detachably provided with respect to the work hand 310.

[0074] By the master hand 210 gripping the third gripping part 120C, the work hand 310 can be attached to the robot 21. The robot 21 can convey the work W using the work hand 310.

[0075] The teaching hand 710 has a touch probe 720. The teaching hand 710 is used for the teaching operation of the robot 21 using the touch probe 720.

[0076] The teaching hand 710 further has a fourth gripping part 120D. The fourth gripping part 120D corresponds to the above-mentioned gripping part 120 and is configured to be grippable by the master hand 210. The touch probe 720 has a pin-shaped contact 720g that contacts the measurement object. The fourth gripping part 120D has a grip shape that extends in a direction orthogonal to the direction in which the contact 720g extends in a pin shape. The fourth gripping part 120D is detachably provided on the teaching hand 710.

[0077] By the master hand 210 gripping the fourth gripping part 120D, the teaching hand 710 can be attached to the robot 21.

[0078] The first gripping part 120A, the second gripping part 120B, the third gripping part 120C, and the fourth gripping part 120D have the same grip shape as each other. The master hand 210 is configured to be able to selectively grip any one of the gripping parts 120 of the first gripping part 120A, the second gripping part 120B, the third gripping part 120C, and the fourth gripping part 120D.

[0079] FIG. 9 is a block diagram showing the control system of the conveyance system in FIG. 1. Referring to FIG. 9, the conveyance system 100 further has a control device 610.

[0080] Each component of the control device 610 is realized by hardware including an arithmetic unit such as a CPU (Central Processing Unit) and various computer processors, a storage device such as a memory or a storage, and a wired or wireless communication line connecting them, and software stored in the storage device and supplying processing instructions to the arithmetic unit. The computer program constituting the software may be composed of a device driver, an operating system, various application programs located in upper layers thereof, or a library providing common functions to these programs. The computer program may be recorded on a computer-readable storage medium or a non-transitory computer-readable storage medium. The computer program may be included in a computer program product. Each block described below indicates a functional unit block.

[0081] The control device 610 includes an operation reception unit 660 and a robot control unit 620. The operation reception unit 660 receives, for example, an operator's operation through a display unit 670 (operation unit) composed of a touch panel display. The operation reception unit 660 outputs a signal corresponding to the operator's operation to the robot control unit 620.

[0082] The robot control unit 620 controls the operation of the robot 21 (including the operation of the work hand 310 attached to the master hand 210).

[0083] The robot control unit 620 includes a program storage unit 621, a program analysis unit 622, an axis control unit 623, a hand control unit 624, and a parameter storage unit 625.

[0084] The program storage unit 621 stores various operation programs 641 that command the operations of the robot 21. The operation programs 641 stored in the program storage unit 621 include, for example, operation commands that define the movement and stop of the robot 21, position commands that define the position and orientation (posture) of the master hand 210, path commands that define movement paths such as linear movement and arc movement, and speed commands that define the movement speed. The operation program 641 is input via the input / output device 630 connected to the robot control unit 620 and stored in the program storage unit 621.

[0085] The operation program 641 is described in a language called, for example, SLIM (Standard Language for Industrial Manipulators). The specific positions and orientations (postures) in each position command included in the operation program 641 are obtained by operating the robot 21 through a manual operation called a teaching operation. As the robot 21 operates by the teaching operation, the rotational angle positions of the respective drive servo motors 23 built in the robot 21 are acquired as parameters, and the acquired parameters are stored in the parameter storage unit 625 via the input / output device 630.

[0086] The program analysis unit 622 reads out the operation program 641 stored in the program storage unit 621 and to be executed, in response to a signal from the operation reception unit 660. The program analysis unit 622 analyzes the operation program 641, extracts commands related to movement, and transmits the commands to the axis control unit 623. The program analysis unit 622 analyzes the operation program 641, extracts commands related to hand operations, and transmits the commands to the hand control unit 624.

[0087] The axis control unit 623 controls the plurality of drive servo motors 23 in response to commands from the program analysis unit 622. The hand control unit 624 controls the master hand 210 and / or the work hand 310 in response to commands from the program analysis unit 622.

[0088] Specifically, the axis control unit 623 reads parameters corresponding to each position command from the parameter storage unit 625, so that the rotation angle position of each drive servo motor 23 becomes the read rotation angle position, and the movement path of the master hand 210 becomes the commanded movement path (linear movement or circular movement). Further, a rotation command (control signal) for each drive servo motor 23 is generated so as to move at the commanded speed and transmitted to each drive servo motor 23. The plurality of drive servo motors 23 move the master hand 210 to the commanded position by having a drive current supplied corresponding to the rotation command from the axis control unit 623.

[0089] The hand control unit 624 generates an opening / closing command for the air valve so that the pair of pistons 226 slide according to a command from the program analysis unit 622, and transmits the opening / closing command to the clamp mechanism 220. The hand control unit 624 generates an opening / closing command for the air valve so that the pair of gripping claws 320 slide according to a command from the program analysis unit 622, transmits the opening / closing command to the piston cylinder 330, or generates a rotation command (control signal) for the servo motor 340 and transmits the rotation command to the servo motor 340.

[0090] Subsequently, a specific example of the usage form of the robot 21 in the transfer system 100 will be described. FIGS. 10 to 15 are top views showing the steps of workpiece machining using a workpiece stocker. FIGS. 10 to 15 correspond to FIG. 2.

[0091] Referring to FIG. 2, in the initial state, a plurality of pallets 410 are stored in the pallet stocker 31. The pallet 410 is equipped with jigs (not shown) such as an ikele or a clamping device. The workpiece stocker 71 stores the unprocessed workpiece W. The hand stocker 81 stores a plurality of workpiece hands 310 and a teaching hand 710. The workpiece hand 310 may have a pair of gripping claws 320 that differ in shape or size from each other among the plurality of workpiece hands 310.

[0092] Referring to FIGS. 9 and 10, the control device 610 (robot control unit 620) controls the robot 21 such that the master hand 210 grips the first gripping portion 120A of the pallet 410 stored in the pallet stocker 31.

[0093] In this step, the master hand 210 moves toward the pallet stocker 31 and is positioned to face the first gripping portion 120A of the pallet 410 in the Z-axis direction. As the master hand 210 moves in the Z-axis direction, the first gripping portion 120A is inserted into the grip insertion hole 221. The master hand 210 grips the first gripping portion 120A. As the master hand 210 moves upward, the pallet 410 is lifted from the shelf board 510.

[0094] Referring to FIGS. 9 and 11, next, the control device 610 (robot control unit 620) controls the robot 21 such that the pallet 410 gripped by the master hand 210 moves to the machining area 12 of the machine tool 10.

[0095] In this step, the master hand 210 enters the machining area 12 and places the pallet 410 on a table (not shown). The pallet 410 is held on the table by a clamp mechanism built into the table. The master hand 210 releases the first gripping portion 120A and exits the machining area 12.

[0096] Referring to FIGS. 9 and 12, next, the control device 610 (robot control unit 620) controls the robot 21 such that the master hand 210 grips the third gripping portion 120C of the work hand 310 stored in the hand stocker 81.

[0097] In this step, the master hand 210 moves toward the hand stocker 81. By gripping the third gripping portion 120C with the master hand 210, the work hand 310 is attached to the robot 21.

[0098] Referring to FIGS. 9 and 13, next, the control device 610 (robot control unit 620) controls the robot 21 and the workpiece hand 310 so that the workpiece hand 310 holds the workpiece W.

[0099] In this step, the workpiece hand 310 moves toward the workpiece stocker 71. The workpiece hand 310 grips the unprocessed workpiece W.

[0100] Referring to FIGS. 9 and 14, next, the control device 610 (robot control unit 620) controls the robot 21 and the workpiece hand 310 so that the workpiece W gripped by the workpiece hand 310 is held by the pallet 410 disposed in the machining area 12 of the machine tool 10.

[0101] In this step, the workpiece hand 310 enters the machining area 12 and places the workpiece W on the jig on the pallet 410. The jig holds the workpiece W, and the workpiece hand 310 releases the workpiece W. The workpiece hand 310 exits the machining area 12. Subsequently to this step, the machine tool 10 performs machining of the workpiece W in the machining area 12.

[0102] Referring to FIGS. 9 and 15, next, the control device 610 (robot control unit 620) controls the robot 21 and the workpiece hand 310 so as to store the machined workpiece W' in the workpiece stocker 71.

[0103] In this step, the workpiece hand 310 enters the machining area 12. The workpiece hand 310 grips the machined workpiece W', and the jig on the pallet 410 releases the workpiece W'. The workpiece hand 310 that has gripped the workpiece W' exits the machining area 12 and moves toward the workpiece stocker 71. The workpiece hand 310 places the workpiece W' in the workpiece stocker 71 and releases the workpiece W'. Through the above steps, the workpiece machining using the workpiece stocker 71 is completed.

[0104] Figures 16 to 20 are top views showing the steps of workpiece machining using a setup station. Figures 16 to 20 correspond to Figure 2.

[0105] Referring to Figure 2, the initial state is the same as the workpiece machining using the above workpiece stocker 71.

[0106] Referring to Figures 9 and 16, the control device 610 (robot control unit 620) controls the robot 21 so that the master hand 210 grips the first gripping portion 120A of the pallet 410 stored in the pallet stocker 31. The control device 610 (robot control unit 620) controls the robot 21 so that the pallet 410 gripped by the master hand 210 moves to the setup station 61.

[0107] In this step, the master hand 210 moves toward the setup station 61 and places the pallet 410 on a pallet mounting table (not shown) installed at the setup station 61. The master hand 210 releases the first gripping portion 120A. The master hand 210 exits from the setup station 61.

[0108] Referring to Figures 9 and 17, next, an operator sets the workpiece W on the pallet 410. In this step, the unprocessed workpiece W is held on the pallet 410 using the jig on the pallet 410.

[0109] Referring to Figures 9 and 18, next, the control device 610 (robot control unit 620) controls the robot 21 so that the master hand 210 grips the first gripping portion 120A of the pallet 410 arranged at the setup station 61.

[0110] Referring to Figures 9 and 19, next, the control device 610 (robot control unit 620) controls the robot 21 so that the pallet 410 gripped by the master hand 210 moves to the machining area 12. Subsequently to this step, the machine tool 10 executes machining of the workpiece W in the machining area 12.

[0111] Referring to FIGS. 9 and 20, next, the control device 610 (robot control unit 620) controls the robot 21 so that the master hand 210 grips the first gripping portion 120A of the pallet 410 disposed in the processing area 12. The control device 610 (robot control unit 620) controls the robot 21 so that the pallet 410 gripped by the master hand 210 moves to the setup station 61. Subsequently to this step, the operator removes the processed workpiece W' from the jig on the pallet 410. Through the above steps, the workpiece processing using the setup station 61 is completed.

[0112] FIGS. 21 to 23 are top views showing the steps of loading pallets onto the pallet stocker. FIGS. 21 to 23 correspond to FIG. 2.

[0113] Referring to FIGS. 9 and 21, in the initial state, the pallet 410 is not stored in the pallet stocker 31. The operator places the pallet 410 on the pallet mounting table (not shown) at the setup station 61.

[0114] Referring to FIGS. 9 and 22, the control device 610 (robot control unit 620) controls the robot 21 so that the master hand 210 grips the first gripping portion 120A of the pallet 410 disposed at the setup station 61. The control device 610 (robot control unit 620) controls the robot 21 so that the pallet 410 gripped by the master hand 210 moves to the pallet stocker 31.

[0115] Referring to FIGS. 9 and 22, next, the control device 610 (robot control unit 620) controls the robot 21 so that the pallet 410 gripped by the master hand 210 is placed on the shelf board 510.

[0116] By repeating the above steps, a plurality of pallets 410 can be loaded into the pallet stocker 31.

[0117] Next, the structure of the work hand 310 will be described in detail. FIG. 24 is a perspective view showing the work hand. FIG. 25 is a front view showing the work hand in FIG. 24. FIG. 26 is a top view showing the work hand in FIG. 24. FIG. 27 is a side view showing the work hand in FIG. 24.

[0118] In FIGS. 24 to 27 and FIGS. 28 to 34 to be described later, for the convenience of explaining the structure of the work hand 310, coordinate axes composed of the x-axis, y-axis, and z-axis are shown. The x-axis extends in the sliding direction of the gripping claws 320, the y-axis is in a direction orthogonal to the x-axis and extends in the extending direction of the gripping claws 320, and the z-axis extends in a direction orthogonal to each of the x-axis and y-axis.

[0119] Referring to FIGS. 24 to 27, the work hand 310 has a pair of gripping claws 320, namely, a first gripping claw 320A and a second gripping claw 320B.

[0120] Each of the gripping claws 320 of the first gripping claw 320A and the second gripping claw 320B extends in the y-axis direction. The first gripping claw 320A and the second gripping claw 320B are opposed to each other with a space therebetween in the x-axis direction. The work hand 310 is configured to be able to grip the work W between the first gripping claw 320A and the second gripping claw 320B.

[0121] The work hand 310 has a first drive mechanism 351 and a second drive mechanism 352. The first drive mechanism 351 has the aforementioned servo motor 340. The first drive mechanism 351 uses the output from the servo motor 340 as a driving force to slide the first gripping claw 320A and the second gripping claw 320B along the x-axis direction. The second drive mechanism 352 has the aforementioned piston cylinder 330. The second drive mechanism 352 uses the output from the piston cylinder 330 as a driving force to slide the first gripping claw 320A and the second gripping claw 320B along the x-axis direction.

[0122] Note that in the present invention, a configuration may be adopted in which while either one of the first gripping claw and the second gripping claw remains stationary, the other one of the first gripping claw and the second gripping claw slides. Further, the object to be gripped by the first gripping claw and the second gripping claw is not limited to a workpiece, and may be, for example, a tool or a jig for holding a workpiece or a tool.

[0123] The workpiece hand 310 further has a support base 311. The support base 311 is generally composed of a plate member arranged parallel to the x-axis - z-axis plane, with the y-axis direction corresponding to the thickness direction. The support base 311 supports a pair of gripping claws 320, a first drive mechanism 351, and a second drive mechanism 352. The third gripping portion 120C is connected to the support base 311. The third gripping portion 120C is detachably attached to the support base 311. The third gripping portion 120C has a grip shape centered on the central axis 126. The central axis 126 extends in the z-axis direction.

[0124] In the side view seen in the x-axis direction shown in FIG. 27, the pair of gripping claws 320 are provided at positions shifted in the z-axis direction and the y-axis direction from the third gripping portion 120C. The first drive mechanism 351 is arranged between the pair of gripping claws 320 and the second drive mechanism 352 in the y-axis direction. In the top view seen in the y-axis direction shown in FIG. 26, the third gripping portion 120C is provided at the central position between the first gripping claw 320A and the second gripping claw 320B in the x-axis direction.

[0125] The support base 311 is further provided with a connector 312 or the like for detachably connecting various wirings and pipes between the robot 21 (master hand 210) and the workpiece hand 310, and an air valve 337 for controlling the supply of air to the piston cylinder 330.

[0126] FIG. 28 is a cross-sectional view showing the work hand as viewed in the arrow direction on line XXVIII-XXVIII in FIG. 24. FIG. 29 is a cross-sectional view showing the work hand as viewed in the arrow direction on line XXIX-XXIX in FIG. 28. FIG. 30 is a cross-sectional view showing the work hand as viewed in the arrow direction on line XXX-XXX in FIG. 28.

[0127] Referring to FIGS. 24 to 30, the work hand 310 has a first slide body 361A and a second slide body 361B (hereinafter, when the first slide body 361A and the second slide body 361B are not particularly distinguished, they are referred to as "slide body 361").

[0128] The first slide body 361A and the second slide body 361B are arranged side by side with a space therebetween in the x-axis direction. The first slide body 361A supports the first gripping claw 320A so as to be slidable along the x-axis direction. The second slide body 361B supports the second gripping claw 320B so as to be slidable along the x-axis direction.

[0129] As shown in FIGS. 28 and 30, the gripping claw 320 has a claw main body portion 321 and a base portion 322. The base portion 322 is a portion supported by the slide body 361. The base portion 322 has a pair of protrusions 323. The pair of protrusions 323 are respectively provided at both ends of the base portion 322 in the z-axis direction. Each protrusion 323 has a convex shape protruding in the z-axis direction. The claw main body portion 321 is the main body portion of the gripping claw 320 for gripping the work W and extends in the y-axis direction from the base portion 322.

[0130] The slide body 361 has a slide main body portion 366 and a guide portion 362. The slide main body portion 366 is a portion to which the driving force from the second driving mechanism 352 is applied. The guide portion 362 is a portion for guiding the gripping claw 320. The guide portion 362 is connected to the end of the slide main body portion 366 in the y-axis direction.

[0131] The slide body 361 is provided with a groove portion 367. The groove portion 367 corresponds to the depth direction in the y-axis direction, has a concave shape that opens in one direction along the y-axis direction, and extends in the x-axis direction. The groove portion 367 penetrates the guide portion 362 in the y-axis direction, enters the slide main body portion 366, and forms a groove bottom inside the slide main body portion 366.

[0132] The guide portion 362 is provided with a pair of guide grooves 363. The guide portion 362 faces each other in the z-axis direction and has a pair of inner walls that respectively form both side walls of the groove portion 367. Each of the pair of guide grooves 363 extends in the x-axis direction while having a concave shape that is recessed in the z-axis direction from the pair of inner walls. A pair of protrusion portions 323 are respectively fitted into the pair of guide grooves 363.

[0133] FIG. 31 is a cross-sectional view showing the work hand as viewed in the arrow direction on XXXI-XXXI in FIG. 28.

[0134] Referring to FIGS. 28 to 31, the first drive mechanism 351 further includes a first screw 343A and a second screw 343B (hereinafter, when the first screw 343A and the second screw 343B are not particularly distinguished, they are referred to as "screw 343").

[0135] The screw 343 extends along a predetermined axis 127. The predetermined axis 127 is an imaginary straight line extending in the x-axis direction and corresponds to the rotation center of the screw 343. A screw (male screw) that extends spirally around the predetermined axis 127 is provided on the outer peripheral surface of the screw 343. The screw provided on the first screw 343A and the screw provided on the second screw 343B are in opposite directions in the circumferential direction of the predetermined axis 127.

[0136] The first screw 343A is supported by the first slide body 361A so as to be rotatable about the predetermined axis 127. The first screw 343A is supported by the first slide body 361A via a bearing 347. The first screw 343A is disposed in the groove portion 367 of the first slide body 361A. A rotational motion from the servo motor 340 is input to the first screw 343A.

[0137] The servo motor 340 is configured to output a rotational motion in the forward rotation direction and the reverse rotation direction about the central axis 128. The central axis 128 is a virtual straight line extending in the x-axis direction and corresponds to the rotation center of the rotational motion output from the servo motor 340. The central axis 128 is arranged at a distance from the predetermined axis 127 in the z-axis direction. The servo motor 340 is provided at a position facing the first screw 343A in the z-axis direction.

[0138] The first drive mechanism 351 further includes a first gear 371 and a second gear 372. The first gear 371 is arranged about the central axis 128. The first gear 371 is connected to the output shaft of the servo motor 340. The second gear 372 is arranged about the predetermined axis 127. The second gear 372 is connected to the end portion of the first screw 343A in the x-axis direction. The second gear 372 meshes with the first gear 371. The rotational motion from the servo motor 340 is transmitted to the first screw 343A via the first gear 371 and the second gear 372.

[0139] The second screw 343B is arranged side by side with the first screw 343A in the x-axis direction. The second screw 343B is supported by the second slide body 361B so as to be rotatable about the predetermined axis 127. The second screw 343B is supported by the second slide body 361B via a bearing 348. The second screw 343B is disposed in the groove portion 367 of the second slide body 361B.

[0140] The first drive mechanism 351 further includes a first nut 344A and a second nut 344B (hereinafter, when the first nut 344A and the second nut 344B are not particularly distinguished, they are referred to as "nut 344").

[0141] The first nut 344A is screwed onto the first screw 343A. The first nut 344A is connected to the first gripping claw 320A. The first nut 344A slides in the x-axis direction integrally with the first gripping claw 320A. The second nut 344B is screwed onto the second screw 343B. The second nut 344B is connected to the second gripping claw 320B. The second nut 344B slides in the x-axis direction integrally with the second gripping claw 320B.

[0142] The nut 344 is provided integrally with the base 322 of the gripping claw 320. The nut 344 is provided on the side opposite to the claw main body 321 with respect to the base 322 in the y-axis direction. The first nut 344A is disposed in the groove 367 of the first slide body 361A. The first nut 344A is slidably supported in the x-axis direction by the inner wall of the first slide body 361A forming the groove 367. The first nut 344A forms a ball screw in pair with the first screw 343A. The second nut 344B is disposed in the groove 367 of the second slide body 361B. The second nut 344B is slidably supported in the x-axis direction by the inner wall of the second slide body 361B forming the groove 367. The second nut 344B forms a ball screw in pair with the second screw 343B.

[0143] The first drive mechanism 351 further includes a connecting portion 342. The connecting portion 342 connects the first screw 343A and the second screw 343B. The connecting portion 342 is configured to restrict the relative rotational movement of the first screw 343A and the second screw 343B about a predetermined axis 127, and to allow the relative sliding movement of the first screw 343A and the second screw 343B in the axial direction of the predetermined axis 127.

[0144] The connecting portion 342 restricts the relative rotational movement of the first screw 343A and the second screw 343B around the predetermined axis 127, so that when the first gripping claws 320A and the second gripping claws 320B slide by the first drive mechanism 351, the rotational movement of the first screw 343A around the predetermined axis 127 is transmitted to the second screw 343B.

[0145] The connecting portion 342 allows the relative sliding movement of the first screw 343A and the second screw 343B in the axial direction of the predetermined axis 127, so that when the first gripping claws 320A and the second gripping claws 320B slide by the second drive mechanism 352, the relative sliding movement of the first slide body 361A and the second slide body 361B in the axial direction of the predetermined axis 127 is enabled.

[0146] More specifically, the first screw 343A and the second screw 343B each have a first tip portion 346A and a second tip portion 346B (hereinafter, when the first tip portion 346A and the second tip portion 346B are not particularly distinguished, they are referred to as "tip portion 346").

[0147] The tip portion 346 is the end portion of the screw 343 in the x-axis direction and extends along the predetermined axis 127. The first tip portion 346A and the second tip portion 346B face each other with a gap in the x-axis direction. The tip portion 346 has a non-circular cross-sectional shape when cut by a plane orthogonal to the predetermined axis 127. The tip portion 346 has a rectangular cross-sectional shape when cut by a plane orthogonal to the predetermined axis 127.

[0148] Note that the tip portion 346 may have a cross-sectional shape of a polygon other than a rectangle when cut by a plane orthogonal to the predetermined axis 127. The tip portion 346 may be composed of a spline shaft in which a plurality of teeth are arranged in the circumferential direction of the predetermined axis 127 and each tooth extends in the axial direction of the predetermined axis 127.

[0149] The connecting portion 342 is composed of a cylindrical body extending in the x-axis direction. When the connecting portion 342 is cut by a plane orthogonal to the predetermined axis 127, it has an opening shape corresponding to the cross-sectional shape of the tip portion 346. The connecting portion 342 has a rectangular opening shape when cut by a plane orthogonal to the predetermined axis 127. A first tip portion 346A is fitted to one end of the connecting portion 342 in the x-axis direction. A second tip portion 346B is fitted to the other end of the connecting portion 342 in the x-axis direction.

[0150] The tip portion 346 is capable of sliding in the x-axis direction when fitted to the connecting portion 342. The tip portion 346 is non-rotatable relative to the connecting portion 342 about the predetermined axis 127 when fitted to the connecting portion 342.

[0151] In such a configuration, when the first drive mechanism 351 is driven and the rotational movement in the forward rotation direction from the servo motor 340 is transmitted to the first screw 343A via the first gear 371 and the second gear 372, the first screw 343A and the second screw 343B connected to the first screw 343A by the connecting portion 342 rotate in one direction about the predetermined axis 127. At this time, since the screw provided on the first screw 343A and the screw provided on the second screw 343B are in opposite directions in the circumferential direction of the predetermined axis 127, the first nut 344A and the second nut 344B move in a direction approaching each other in the x-axis direction. As a result, the first gripping claw 320A and the second gripping claw 320B slide in a direction approaching each other in the x-axis direction.

[0152] Also, when the rotational movement in the reverse direction from the servo motor 340 is transmitted to the first screw 343A via the first gear 371 and the second gear 372, the first screw 343A and the second screw 343B connected to the first screw 343A by the connecting portion 342 rotate in the reverse direction about the predetermined axis 127. At this time, the first nut 344A and the second nut 344B move in a direction away from each other in the x-axis direction. Thereby, the first gripping claw 320A and the second gripping claw 320B slide in a direction away from each other in the x-axis direction.

[0153] Note that when the servo motor 340 slides the first gripping claw 320A and the second gripping claw 320B, the first slide body 361A and the second slide body 361B remain stationary in the x-axis direction.

[0154] FIG. 32 is a cross-sectional view showing the internal structure of the piston cylinder in FIG. 28. Referring to FIGS. 28, 30, and 32, the second drive mechanism 352 slides the first slide body 361A and the second slide body 361B in the x-axis direction. At this time, the first gripping claw 320A slides in the x-axis direction integrally with the first slide body 361A, and the second gripping claw 320B slides in the x-axis direction integrally with the second slide body 361B.

[0155] The piston cylinder 330 is supported by the support base 311. The piston cylinder 330 is disposed between the support base 311 and the slide body 361 in the y-axis direction. The gripping claw 320 (claw main body portion 321) extends in the y-axis direction from the slide body 361 to the side opposite to the piston cylinder 330. The piston cylinder 330 is provided at a position radially outward from the connecting portion 342 with respect to the predetermined axis 127.

[0156] The piston cylinder 330 has a piston 332 and a power transmission unit 334. The piston 332 moves linearly (reciprocates) along the y-axis direction. The piston cylinder 330 is an air type that is operated by air pressure to the piston 332. The power transmission unit 334 converts the linear motion along the y-axis direction from the piston 332 into a linear motion along the x-axis direction and transmits the linear motion to the first slide body 361A and the second slide body 361B.

[0157] The power transmission unit 334 has a first wedge block 331A and a second wedge block 331B (hereinafter, when the first wedge block 331A and the second wedge block 331B are not particularly distinguished, they are referred to as "wedge block 331"). The first wedge block 331A and the second wedge block 331B are arranged at intervals in the x-axis direction. The wedge block 331 is slidably supported in the x-axis direction by a guide block 336.

[0158] The first wedge block 331A is connected to the first slide body 361A. The first wedge block 331A is fastened to the slide main body 366 of the first slide body 361A using bolts. The second wedge block 331B is connected to the second slide body 361B. The second wedge block 331B is fastened to the slide main body 366 of the second slide body 361B using bolts.

[0159] The first wedge block 331A has a first tapered surface 331a. The second wedge block 331B has a second tapered surface 331b. The first tapered surface 331a and the second tapered surface 331b face each other at intervals in the x-axis direction. The first tapered surface 331a and the second tapered surface 331b are inclined with respect to the y-axis such that the distance between the first tapered surface 331a and the second tapered surface 331b in the x-axis direction changes in the y-axis direction. The distance between the first tapered surface 331a and the second tapered surface 331b in the x-axis direction becomes smaller as it approaches the slide body 361 in the y-axis direction and becomes larger as it moves away from the slide body 361.

[0160] The power transmission unit 334 further includes a third wedge block 333. The third wedge block 333 is connected to the tip of the piston 332 in the y-axis direction. The third wedge block 333 is disposed between the first wedge block 331A and the second wedge block 331B in the x-axis direction. The first wedge block 331A and the second wedge block 331B are biased against the third wedge block 333 in the x-axis direction by the elastic force of a spring member (not shown).

[0161] The third wedge block 333 has a third tapered surface 333a and a fourth tapered surface 333b. The third tapered surface 333a is parallel to the first tapered surface 331a. The third tapered surface 333a is in surface contact with the first tapered surface 331a. The fourth tapered surface 333b is parallel to the second tapered surface 331b. The fourth tapered surface 333b is in surface contact with the second tapered surface 331b.

[0162] In such a configuration, when the second drive mechanism 352 is driven and the piston 332 moves linearly in a direction away from the slide body 361 in the y-axis direction as shown by the arrow 132 in FIG. 32 (when the piston cylinder 330 is driven to contract), the first wedge block 331A and the second wedge block 331B move in a direction approaching each other in the x-axis direction as shown by the arrow 134 in FIG. 32. As a result, the first gripping claw 320A and the second gripping claw 320B slide in a direction approaching each other in the x-axis direction.

[0163] Also, when the piston 332 moves linearly in a direction approaching the slide body 361 in the y-axis direction as shown by the arrow 131 in FIG. 32 (when the piston cylinder 330 is driven to extend), the first wedge block 331A and the second wedge block 331B move in a direction away from each other in the x-axis direction as shown by the arrow 133 in FIG. 32. As a result, the first gripping claw 320A and the second gripping claw 320B slide in a direction away from each other in the x-axis direction.

[0164] Note that when the first gripping claws 320A and the second gripping claws 320B are sliding due to the second drive mechanism 352 (piston cylinder 330), the first gripping claws 320A and the second gripping claws 320B remain stationary in the x-axis direction with respect to the first slide body 361A and the second slide body 361B, respectively.

[0165] FIG. 33 is a diagram schematically showing the sliding operation of the first gripping claws and the second gripping claws by the first drive mechanism (servo motor). FIG. 34 is a diagram schematically showing the sliding operation of the first gripping claws and the second gripping claws by the second drive mechanism (piston cylinder).

[0166] Referring to FIGS. 9, 33, and 34, the operator inputs in advance the width of the workpiece W in the x-axis direction through the display unit 670 (operation unit) composed of a touch panel display. The input width of the workpiece W is stored in the parameter storage unit 625. The parameter storage unit 625 further stores the stroke length St of the piston cylinder 330 in the second drive mechanism 352.

[0167] In FIGS. 33 and 34, it is assumed that the workpiece W having a width of the third length Lc is gripped by the first gripping claws 320A and the second gripping claws 320B. The distance between the first gripping claws 320A and the second gripping claws 320B in the x-axis direction in the initial state is the first length La. The first length La is larger than the third length Lc (La > Lc).

[0168] The first length La may be the maximum separation width between the first gripping claws 320A and the second gripping claws 320B. In this case, the first length La is determined by the specifications of the workpiece hand 310 attached to the robot 21.

[0169] Next, the control device 610 (robot control unit 620) controls the robot 21 so that the workpiece W is disposed between the first gripping claws 320A and the second gripping claws 320B.

[0170] Next, the robot control unit 620 reads out the third length Lc, which is the width of the workpiece W, and the stroke length St of the piston cylinder 330 from the parameter storage unit 625. The robot control unit 620 calculates the sum of the third length Lc and the stroke length St of the first gripping claw 320A and the second gripping claw 320B by the piston cylinder 330, and sets the calculated value as the second length Lb (Lb = Lc + St).

[0171] The second length Lb is smaller than the first length La and larger than the third length Lc (Lc < Lb < La). The stroke length St is the slide length of the first wedge block 331A and the second wedge block 331B in the x-axis direction, which is determined by the specifications of the piston cylinder 330. The stroke length St may be, for example, 10 mm or less, 5 mm or less, or 3 mm or less.

[0172] Next, the control device 610 (robot control unit 620) controls the first drive mechanism 351 (servo motor 340) so that the distance between the first gripping claw 320A and the second gripping claw 320B in the x-axis direction changes from the first length La to the second length Lb.

[0173] In this step, when the servo motor 340 in the first drive mechanism 351 is driven, the first gripping claw 320A and the second gripping claw 320B slide in a direction approaching each other.

[0174] Next, the control device 610 (robot control unit 620) controls the second drive mechanism 352 (piston cylinder 330) so that the distance between the first gripping claw 320A and the second gripping claw 320B in the x-axis direction changes from the second length Lb to the third length Lc.

[0175] In this step, when the piston cylinder 330 in the second drive mechanism 352 is driven to shorten, the first gripping claw 320A and the second gripping claw 320B slide in a direction approaching each other.

[0176] In this embodiment, the slide length (St = Lb - Lc) of the first gripping claws 320A and the second gripping claws 320B by the second drive mechanism 352 is smaller than the slide length (La - Lb) of the first gripping claws 320A and the second gripping claws 320B by the first drive mechanism 351 (Lb - Lc < La - Lb). Depending on the dimensions of the workpiece W, the slide length (St = Lb - Lc) of the first gripping claws 320A and the second gripping claws 320B by the second drive mechanism 352 may be equal to or greater than the slide length (La - Lb) of the first gripping claws 320A and the second gripping claws 320B by the first drive mechanism 351 (Lb - Lc ≧ La - Lb).

[0177] When the first gripping claws 320A and the second gripping claws 320B release the workpiece W, the above steps for gripping the workpiece W may be executed in the reverse order.

[0178] Summarizing the structure of the workpiece hand 310 in the embodiment of this invention described above, the workpiece hand 310 as a hand device in this embodiment includes a first gripping claw 320A, a second gripping claw 320B that faces the first gripping claw 320A at an interval and grips the workpiece W as an object together with the first gripping claw 320A, a servo motor 340 as a motor, and uses the output from the servo motor 340 as a driving force to slide at least one of the gripping claws 320 of the first gripping claws 320A and the second gripping claws 320B. The first drive mechanism 351, an air-type piston cylinder 330, and uses the output from the piston cylinder 330 as a driving force to slide at least one of the gripping claws 320 of the first gripping claws 320A and the second gripping claws 320B. And a second drive mechanism 352.

[0179] Assume that the work hand 310 has only a motor as a power source for sliding the gripping claws 320. In this case, since the thrust of the motor is small, there are problems such as the gripping force of the work W by the gripping claws 320 not being sufficiently obtained, or the motor becoming extremely large in size in order to obtain sufficient gripping force. On the other hand, assume that the work hand 310 has only a piston cylinder as a power source for sliding the gripping claws 320. In this case, since there is a limit to the stroke of the piston cylinder, various workpieces W with different dimensions cannot be gripped by a single work hand, resulting in a problem that the versatility of the work hand is reduced.

[0180] In contrast, in the work hand 310 of the present embodiment, by using the first drive mechanism 351 with the output from the servo motor 340 as the driving force for the sliding operation of the gripping claws 320, the sliding length of the gripping claws 320 can be sufficiently ensured. As a result, it is possible to grip various workpieces W with different dimensions without preparing a large number of work hands 310. Also, by using the second drive mechanism with the output from the piston cylinder 330 as the driving force for the sliding operation of the gripping claws 320, a sufficient gripping force for the work W can be obtained. Thereby, it is possible to more reliably prevent the work W from falling off the work hand 310.

[0181] Further, when gripping the work W by the first gripping claw 320A and the second gripping claw 320B, the first drive mechanism 351 slides the gripping claws 320 so that the distance between the first gripping claw 320A and the second gripping claw 320B changes from the first length La to the second length Lb which is smaller than the first length La, and the second drive mechanism 352 slides the gripping claws 320 so that the distance between the first gripping claw 320A and the second gripping claw 320B changes from the second length Lb to the third length Lc which is smaller than the second length Lb.

[0182] According to such a configuration, by adjusting the second length Lb according to the dimensions of the workpiece W, first, the first gripping claws 320A and the second gripping claws 320B are positioned with respect to the workpiece W by driving the first drive mechanism 351. Further, by driving the second drive mechanism 352, the workpiece W can be gripped by the first gripping claws 320A and the second gripping claws 320B with sufficient gripping force.

[0183] Also, the slide length (Lb - Lc) of the first gripping claws 320A and the second gripping claws 320B by the second drive mechanism 352 is smaller than the slide length (La - Lb) of the first gripping claws 320A and the second gripping claws 320B by the first drive mechanism 351.

[0184] According to such a configuration, by relatively reducing the stroke length St (= Lb - Lc) of the piston cylinder 330 when gripping the workpiece W, it is possible to suppress an excessive force from being applied to the workpiece W from the first gripping claws 320A and the second gripping claws 320B. Thereby, breakage of the workpiece W can be prevented.

[0185] In addition, the workpiece hand 310 supports the first gripping claw 320A so as to be slidable along the x-axis direction as the first direction, and includes a first slide body 361A that is slid in the x-axis direction by the second drive mechanism 352. The workpiece hand 310 also supports the second gripping claw 320B so as to be slidable along the x-axis direction, and further includes a second slide body 361B that is slid in the x-axis direction by the second drive mechanism 352. The first drive mechanism 351 is supported by the first slide body 361A so as to be rotatable about a predetermined axis 127 parallel to the x-axis direction, and includes a first screw 343A to which a rotational motion from the servo motor 340 is input. The first drive mechanism 351 further includes a first nut 344A that is screwed onto the first screw 343A and connected to the first gripping claw 320A. The second drive mechanism 352 is supported by the second slide body 361B so as to be rotatable about the predetermined axis 127, and includes a second screw 343B provided with a screw in a direction opposite to that of the screw provided on the first screw 343A. The second drive mechanism 352 further includes a second nut 344B that is screwed onto the second screw 343B and connected to the second gripping claw 320B. The second drive mechanism 352 further includes a connecting portion 342 that connects the first screw 343A and the second screw 343B so as to regulate a relative rotational motion of the first screw 343A and the second screw 343B about the predetermined axis 127 and allow a relative sliding motion of the first screw 343A and the second screw 343B in the axial direction of the predetermined axis 127.

[0186] According to such a configuration, the connecting portion 342 restricts the relative rotational movement of the first screw 343A and the second screw 343B about the predetermined axis 127, thereby enabling the transmission of the rotational movement about the predetermined axis 127 between the first screw 343A and the second screw 343B during the sliding movement of the first gripping claws 320A and the second gripping claws 320B by the first drive mechanism 351. Further, by allowing the connecting portion 342 to permit the relative sliding movement of the first screw 343A and the second screw 343B in the axial direction of the predetermined axis 127, the relative sliding movement of the first slide bodies 361A and the second slide bodies 361B in the axial direction of the predetermined axis 127 can be enabled during the sliding movement of the first gripping claws 320A and the second gripping claws 320B by the second drive mechanism 352.

[0187] Further, the piston cylinder 330 includes a piston 332 that linearly moves along the y-axis direction as a second direction orthogonal to the x-axis direction, and a power transmission portion 334 that converts the linear movement along the y-axis direction from the piston 332 into a linear movement along the x-axis direction and transmits the linear movement to the first slide bodies 361A and the second slide bodies 361B.

[0188] According to such a configuration, the piston cylinder 330 can be configured to be compact in the x-axis direction.

[0189] In the workpiece hand 310 of the present embodiment, it is also possible to slide the gripping claws 320 using only the first drive mechanism 351 that uses the output from the servo motor 340 as a driving force. In this case, the control device 610 (robot control unit 620) may monitor the torque load through the current value of the servo motor 340 and perform control according to the torque load.

[0190] As an example, the gripping claws 320 are slid by the first drive mechanism 351 to grip a workpiece W made of resin or a thin material. At this time, when the current value of the servo motor 340 exceeds the threshold value, the control device 610 (robot control unit 620) stops the servo motor 340. Thereby, an excessive gripping force is prevented from being applied to the workpiece W from the gripping claws 320, and as a result, breakage of the workpiece W can be avoided.

[0191] As another example, the workpiece W is gripped by sliding the gripping claws 320 by the first drive mechanism 351. At this time, the control device 610 (robot control unit 620) detects the angular position of the servo motor 340 when the current value of the servo motor 340 exceeds the threshold value from an encoder or the like of the servo motor 340. The control device 610 (robot control unit 620) calculates the dimensions of the workpiece W based on the detected angular position of the servo motor 340.

[0192] As yet another example, a positioning block for the workpiece W is installed on the workpiece stocker 71. The gripping claws 320 are slid by the first drive mechanism 351, and the workpiece W is pressed against the positioning block by the gripping claws 320. At this time, when the current value of the servo motor 340 exceeds the threshold value, the control device 610 (robot control unit 620) stops the servo motor 340. Thereby, the workpiece W can be pressed against the positioning block with an appropriate force, and the workpiece W can be arranged at an appropriate position in the workpiece stocker 71.

[0193] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0194] 10, 10S, 10T machine tools, 12 machining area, 14 cover body, 16 opening, 18 operation panel, 21 robot, 22 robot base, 23 drive servo motor, 26 base part, 27 first arm, 28 second arm, 29 hand attachment part, 31, 31S, 31T pallet stocker, 51 transfer operation panel, 56, 56h, 56i, 56j, 56k fence, 61, 61S, 61T setup station, 71 work stocker, 81 hand stocker, 100 transfer system, 101 swivel center axis, 102, 103, 105 rotation center axis, 104, 106 rotary center axis, 113 space, 120 gripping part, 120A first gripping part, 120B second gripping part, 120C third gripping part, 120D fourth gripping part, 121, 367 groove part, 126, 128, 231 center axis, 127 predetermined axis, 210 master hand, 220 clamp mechanism, 221 grip insertion hole, 226, 332 piston, 227, 323 protrusion, 230 sensor, 310 work hand, 311 support base, 320 gripping claw, 320A first gripping claw, 320B second gripping claw, 321 claw body part, 322 base part, 330 piston cylinder, 331 wedge block, 331A first wedge block, 331B second wedge block, 331a first tapered surface, 331b second tapered surface, 333 third wedge block, 333a third tapered surface, 333b fourth tapered surface, 334 power transmission part, 336 guide block, 337 air valve, 340 servo motor, 342 connecting part, 343 screw, 343A first screw, 343B second screw, 344 nut, 344A first nut, 344B second nut, 346 tip part, 346A first tip part, 346B second tip part, 347, 348 bearing, 351 first drive mechanism, 352 second drive mechanism, 361 slide body, 361A first slide body, 361B second slide body, 362 guide part, 363 guide groove, 366 slide main body part, 371 first gear, 372 second gear, 410 pallet, 510 shelf board, 515 fixed shelf board, 520, 520p, 520q,520r pallet support part, 525 taper cone receiving part, 531 horizontal frame, 532 vertical frame, 533 pin hole, 550 frame body, 551 pillar, 560 support part, 561 plate, 610 control device, 620 robot control part, 621 program memory part, 622 program analysis part, 623 axis control part, 624 hand control part, 625 parameter memory part, 630 input / output device, 641 operation program, 660 operation reception part, 670 display part, 710 teaching hand, 720 touch probe, 720g contact, La first length, Lb second length, Lc third length, St stroke length, W work.,

Claims

1. A first gripping jaw; a second gripping claw that faces the first gripping claw with a gap therebetween and grips an object together with the first gripping claw; a first drive mechanism including a motor and configured to slide at least one of the first gripping claw and the second gripping claw using an output from the motor as a driving force; a second drive mechanism including an air-operated piston cylinder and configured to slide at least one of the first gripping jaw and the second gripping jaw using an output from the piston cylinder as a driving force; a slide body that supports the gripping claws so that the gripping claws can slide, The first drive mechanism is connected to the gripping claws and causes the gripping claws to slide relative to the sliding body, and the second drive mechanism is connected to the sliding body and causes the sliding body to slide.

2. When the object is gripped by the first gripping jaw and the second gripping jaw, the first drive mechanism slides the gripping jaws such that a distance between the first gripping jaw and the second gripping jaw changes from a first length La to a second length Lb that is smaller than the first length La; 2. The hand device according to claim 1, wherein the second drive mechanism slides the gripping claws so that a distance between the first gripping claw and the second gripping claw changes from the second length Lb to a third length Lc that is smaller than the second length Lb.

3. The hand device according to claim 2, wherein a sliding length (Lb-Lc) of the first gripping claw and the second gripping claw caused by the second drive mechanism is smaller than a sliding length (La-Lb) of the first gripping claw and the second gripping claw caused by the first drive mechanism.

4. As the slide body, a first slider that supports the first gripping claw so as to be slidable along a first direction and is slid in the first direction by the second drive mechanism; a second slider that supports the second gripping claw so as to be slidable along the first direction and is slid in the first direction by the second drive mechanism; The first drive mechanism includes: a first screw supported by the first slide body so as to be rotatable about a predetermined axis parallel to the first direction, and receiving rotational motion from the motor; a first nut that is screwed onto the first screw and connected to the first gripping jaw; a second screw supported by the second slide body so as to be rotatable about the predetermined axis and having a thread in a direction opposite to that of the first screw; a second nut that is screwed onto the second screw and connected to the second gripping jaw; 4. The hand device according to claim 1, further comprising a connecting portion that connects the first screw and the second screw so as to restrict relative rotational movement of the first screw and the second screw around the specified axis and allow relative sliding movement of the first screw and the second screw in the axial direction of the specified axis.

5. The piston cylinder is a piston that moves linearly along a second direction perpendicular to the first direction; 5. The hand device according to claim 4, further comprising: a power transmission unit that converts linear motion from the piston along the second direction into linear motion along the first direction and transmits the linear motion to the first slide body and the second slide body.

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