JP2019171535A - Gripping device - Google Patents

Abstract

To provide a gripping device which can reliably grip a work-piece.SOLUTION: A gripping device 1 comprises a plurality of claw parts 30, which are so provided as to be capable of freely opening/closing, and grip a work-piece. In the gripping device 1, the plurality of claw parts 30 comprise a gripping part 32 and a magnetic force generating part 50. A gripping surface 32A and a pad surface 32B are formed on the gripping part 32. The gripping surface 32A is formed in a form toward an opening/closing direction. The pad surface 32B is formed in a form extending along the opening/closing direction. The gripping part 32 brings the gripping surface 32A and the pad surface 32B into contact with the work-piece when gripping the work-piece. The magnetic force generating part 50 is provided on a back side of the pad surface 32B, and generates magnetic force toward a front direction of the pad surface 32B.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a gripping device.

  Patent Document 1 discloses a conventional gripping device. The gripping device includes a motor and a plurality of clamp bodies. Each clamp body is unitized and each is separately attached to the motor. Each clamp body has a clamp arm. This gripping device grips a workpiece by pressing each clamp arm against a gripped portion of the workpiece and sandwiching the clamp arm between the clamp arms.

JP 2010-284795 A

  By the way, in this type of gripping device, the workpiece is gripped only by the clamping force of the clamp arm. For this reason, when the gripped portion of the workpiece does not have a sufficient gripped area, the gripping force by the clamp arm may not be sufficiently transmitted. In this case, since the workpiece is not sufficiently gripped, there is a possibility that the gripping position is shifted and the workpiece is tilted or the workpiece is dropped when the workpiece is transported.

  The present invention has been made in view of the above-described conventional situation, and an object to be solved is to provide a gripping device that can securely grip a workpiece.

  The gripping device of the present invention is a device that grips a workpiece with a plurality of claw portions provided so as to be freely opened and closed. In the gripping device, a plurality of claw portions includes a gripping portion and a magnetic force generation portion. A grip surface and a contact surface are formed on the grip portion. The knob surface is formed in a form facing the opening / closing direction. The contact surface is formed in a form extending along the opening and closing direction. The gripping unit causes the picking surface and the contact surface to contact the work when gripping the work. The magnetic force generator is provided on the back side of the contact surface and generates a magnetic force in the front direction of the contact surface.

  With such a configuration, the gripping device of the present invention generates a magnetic force toward the front direction of the contact surface by the magnetic force of the magnetic force generation unit. For this reason, when a workpiece | work has magnetism, a workpiece | work can be attracted and made to contact | abut to the contact surface which is a surface different from a picking surface. As a result, the position and posture of the workpiece can be regulated using the contact surface as a reference surface, so that the gripping surface can be set as desired by performing the gripping operation of the plurality of claws while the workpiece is in contact with the contact surface. It can be held in contact with this position.

  Therefore, the gripping device of the present invention can securely grip the workpiece.

  In the present invention, gripping a workpiece with a plurality of claw portions refers to a form in which the gripping surface is brought into contact with the outer surface of the workpiece by moving the plurality of claw portions in a direction in which they are close to each other, By moving in the separating direction, for example, the gripping surface may be brought into contact with the inner surface of the workpiece, such as the inner peripheral surface of the annular workpiece or the inner surface of the groove of the workpiece in which the groove-shaped portion is formed. it can.

  In the gripping device of the present invention, the magnetic force generation unit may include a permanent magnet that is provided on the back side of the contact surface so as to be movable back and forth toward the contact surface. In this case, the magnetic force of the magnetic force generator can be applied only when desired. Thereby, it can prevent attracting | sucking a workpiece | work unintentionally.

  In the gripping device of the present invention, the magnetic force generator may include an elastic member that applies an elastic force in a direction in which the permanent magnet is separated from the contact surface. In this case, it is possible to realize a mechanism in which the permanent magnet advances and retreats with respect to the contact surface with a simple configuration.

  In the gripping device of the present invention, the knob surface can be formed in a V shape. In this case, even if it is a workpiece | work which has a circumferential surface part, a knob | pick surface can be contact | abutted reliably and a workpiece | work can be hold | gripped reliably.

It is a figure which shows typically the state by which the holding apparatus of Embodiment 1 was attached to the robot. It is a front view which shows the holding | gripping apparatus of Embodiment 1. FIG. FIG. 3 is a diagram illustrating a state in which a main body is removed from a driving unit in the gripping device according to the first embodiment. It is side surface sectional drawing which shows the holding | gripping apparatus of Embodiment 1. It is an expanded sectional view in the VV line of FIG. It is a figure which shows the nail | claw part of the holding | gripping apparatus of Embodiment 1, (A) longitudinal cross-sectional view and (B) bottom view are each shown. It is the VII-VII sectional view taken on the line of FIG. 2A and 2B are diagrams for explaining gripping of a workpiece by the gripping device according to the first embodiment, in which FIG. 3A is a state in which the gripping device is moved above the workpiece, and FIG. (C) shows a state in which the workpiece is gripped by the gripping device. FIGS. 2A and 2B are views (No. 2) for explaining gripping of a workpiece by the gripping device according to the first embodiment, in which FIG. 3A is a state in which the gripping device is moved above the workpiece, and FIG. A state of contact with the upper surface, (C) shows a state in which a magnetic force is applied to the work by the magnetic force generation unit.

  Next, a first embodiment in which the gripping device of the present invention is embodied will be described with reference to the drawings.

<Embodiment 1>
As shown in FIG. 1, the gripping device 1 according to the first embodiment is attached to the tip of an arm 110 of a six-axis robot 100. The gripping device 1 is used for picking the workpiece W. In the present embodiment, the workpiece W is a pin seal. The pin seal is a seal member that is disposed between the joint of the hydraulic cylinder and the joint pin, and prevents foreign matter from entering between the inner peripheral surface of the joint serving as a sliding surface and the outer peripheral surface of the joint pin. The pin seal has an annular shape in which a core metal made of a magnetic metal and having a substantially L-shaped cross section (see FIG. 8 and the like) is insert-molded into synthetic rubber. The gripping device 1 grips the outer peripheral surface of the workpiece W when picking the workpiece W.

  In the gripping device 1, the claw 30 at the distal end can be freely directed in a desired direction by the robot 100, but in the following description, for the sake of convenience, a connecting portion with the arm 110 of the robot 100 on the proximal end side. Is the upper side of the gripping device 1, and the direction of the claw portion 30 on the tip side is the lower side of the gripping device 1. That is, the vertical direction in FIGS. 2 to 4 is defined as the upper and lower sides of the gripping device 1 as they are. Regarding the left-right direction, the left-right direction in FIGS. 2, 3, and 5 is defined as the left side and the right side of the gripping device 1 as they are. Further, the left side in FIG. 4 and the lower side in FIG. 5 are defined as the front side of the gripping device 1, and the right side in FIG. 4 and the upper side in FIG.

  As shown in FIGS. 2 to 4, the gripping device 1 according to this embodiment includes a drive unit 10 and a main body unit 20. The driving unit 10 is fixed to the arm 110 of the robot 100. The main body 20 is detachably provided on the drive unit 10.

<Drive unit 10>
As shown in FIGS. 2 to 4, the drive unit 10 includes a base 11, a guide bush 12, a motor 13, and a drive gear 14. The base 11 is a connecting portion whose upper portion 11 </ b> A is connected to the arm 110. The upper part 11A of the base 11 has an umbrella shape that expands downward in a tapered shape. As shown in FIG. 3, the lower portion of the base 11 is formed by providing a front wall portion 11B and left and right side wall portions 11C and 11D. The front wall portion 11B has a substantially rectangular parallelepiped shape that is longer in the left-right direction than in the up-down direction and flat in the front-rear direction when viewed from the front. The side wall portions 11C and 11D are formed in a form extending rearward from the left and right end portions of the front wall portion 11B. The front wall portion 11B and the left and right side wall portions 11C and 11D as a whole have a substantially U shape that opens rearward in plan view.

  The guide bush 12 is attached to the side walls 11 </ b> C and 11 </ b> D of the base 11. The guide bush 12 is formed in a substantially cylindrical shape having a flange portion 12 </ b> A formed with one end portion having an enlarged diameter and a through-hole 12 </ b> B penetrating in the axial direction. The guide bush 12 is press-fitted into the side wall portions 11C and 11D from the left and right directions in a form in which the flange portion 12A protrudes from the outer surface of the side wall portions 11C and 11D. Two guide bushes 12 are arranged side by side in the vertical direction on the side wall portions 11C and 11D. In the present embodiment, these guide bushes 12 function as a guide portion and a concave portion according to the present invention. Specifically, the guide bush 12 guides the main body 20 in the attaching / detaching direction by sliding on a slide member 23 described later when the main body 20 is attached to and detached from the driving unit 10. Each guide bush 12 inserts and removes lock pins 24 and 25, which will be described later, into and from the through hole 12B.

  The motor 13 is a stepping motor. The motor 13 is connected with electric wiring for driving and signal (not shown) for driving from the robot 100 side, and is driven and controlled by a driver (not shown). As shown in FIGS. 2 to 4, the motor 13 has a substantially square column shape that is long in the front-rear direction. The motor 13 is attached to the base 11 such that the front surface of the motor 13 is brought into contact with the rear surface of the front wall portion 11B of the base 11 and the drive shaft 13A protrudes forward through the front wall portion 11B. The motor 13 includes a drive shaft 13A. The drive shaft 13A protrudes forward from the approximate center of the front surface of the motor 13. The drive gear 14 is a spur gear. The drive gear 14 is fixed to the drive shaft 13A with the boss facing the tip end side of the drive shaft 13A. As shown in FIGS. 2 and 5, the motor 13 is attached with a slight offset to the right from the central axis C of the gripping device 1 in the left-right direction. Therefore, the drive gear 14 fixed to the drive shaft 13 </ b> A of the motor 13 is also arranged offset slightly to the right from the center axis C of the gripping device 1.

<Main body 20>
As shown in FIGS. 2 to 4, the main body 20 includes front and rear case members 21 and 22 and a pair of left and right slide members 23. The case members 21 and 22 form a space therein and house a part of the transmission unit 40 described later. The pair of slide members 23 are attached to both sides of the upper rear surface of the case member 21 in a form protruding rearward. The slide member 23 functions as a guided portion that is slid and guided by the above-described guide bush 12 when the main body portion 20 is attached to and detached from the drive portion 10.

  The slide member 23 is formed with a groove portion 23 </ b> A having a substantially U-shaped cross-sectional shape in plan view that opens in the inner direction of the main body portion 20 and extends vertically. When attaching / detaching the main body 20 to / from the drive unit 10, the groove 23 </ b> A is guided by sliding its bottom surface and inner surface with the end surface and outer peripheral surface of the flange portion 12 </ b> A of the guide bush 12, respectively. In addition, a tapered surface 23B is formed on the bottom wall upper portion of the groove 23A so as to incline outward in the left-right direction. Due to this tapered surface 23B, when the main body portion 20 is mounted on the driving portion 10, a lateral displacement between the end surface of the guide bush 12 and the bottom surface of the groove portion 23A, which is a direction intersecting the attaching / detaching direction, is allowed and smooth. Can be installed easily. Further, positional displacement in the front-rear direction when the main body 20 is mounted on the drive unit 10 is allowed because the outer peripheral surface of the flange portion 12A forms a circumferential surface.

  Two slide pins 24 and 25 are inserted into each slide member 23. The lock pins 24 and 25 function as convex portions that are inserted into and removed from the through holes 12 </ b> B of the guide bush 12 when the main body portion 20 is attached to and detached from the driving portion 10. The lock pins 24 and 25 intersect with the extending direction of the groove 23A, which is the attaching / detaching direction, and the tip protrudes into the groove 23A with the left-right direction as the axial direction, and the groove 23A extends from the outer surface of the slide member 23. It is inserted through the bottom wall. The two lock pins 24 and 25 are arranged side by side along the extending direction of the groove 23A. The distal ends of the lock pins 24 and 25 are provided in the slide member 23 so as to be able to protrude and retract from the groove 23A. The rear ends of the lock pins 24 and 25 are connected to the bracket 27. The bracket 27 is formed in a substantially L shape in plan view having two sides with the front-rear direction and the left-right direction as the extending direction. The bracket 27 connects the lock pins 24 and 25 to a surface extending in the front-rear direction, and an insertion hole 27A penetrating in the plate thickness direction is formed on the surface extending in the left-right direction. Further, as shown in FIG. 5, the lower lock pin 25 is urged in a protruding direction by a coil spring 26. The lock pins 24 and 25 are buried in the slide member 23 by moving the bracket 27 outward in the left-right direction. Further, when the force for moving the bracket 27 in the outward direction is released, the lock pins 24 and 25 return to the state of protruding from the bottom surface of the groove 23A by the action of the coil spring 26.

  Further, the main body 20 has a claw portion 30 and a transmission portion 40. Two claw portions 30 are provided in a form extending below the case members 21 and 22. The two claw portions 30 are provided so as to be openable and closable and grip the workpiece W. The two claw portions 30 open and close in a manner that they approach and separate from each other. The two claw portions 30 are provided facing the left and right of the central axis C of the gripping device 1. Each claw portion 30 has substantially the same configuration. The transmission unit 40 transmits the movement of the driving unit 10 to each of the two claw units 30. The transmission unit 40 moves the two claw portions 30 in synchronization with each other with a central axis C as a predetermined central axis as a reference. In the case of this embodiment, the transmission part 40 linearly translates the two claw parts 30 in the left-right direction which is the orthogonal direction of the central axis C. That is, the opening / closing operation | movement of the some nail | claw part 30 in this embodiment is based on a linear motion.

<Nail part 30>
As shown in FIGS. 6A and 6B, the claw portion 30 has a claw body 31 and a grip portion 32. The claw body 31 has a substantially cylindrical shape extending in the vertical direction, and forms a space S therein. The upper end part of the nail | claw main body 31 is connected to the transmission part 40 mentioned later. The grip portion 32 forms a knob surface 32A and a contact surface 32B. The grip 32 is provided at the lower end of the nail body 31. When gripping the workpiece W, the gripping portion 32 grips the workpiece W by bringing the gripping surface 32A and the contact surface 32B into contact with the workpiece W. The knob surface 32A is a surface for gripping the workpiece W. The knob surface 32 </ b> A is formed so as to face the opening / closing direction of the claw portion 30. In the case of the present embodiment, the knob surface 32A is formed in a form facing the inner direction, which is the direction in which the knob surfaces 32A of the two claw portions 30 face each other. Further, as shown in FIG. 6B, the knob surface 32A has a substantially V shape in plan view, and comes into contact with the outer peripheral surface that is the circumferential surface portion of the workpiece W when the workpiece W is gripped. The contact surface 32B is a surface that assists in gripping the workpiece W. The contact surface 32B corrects the posture of the workpiece W by abutting against the upper surface of the workpiece W when the workpiece W is gripped so that the outer peripheral surface of the workpiece W as a gripped surface is appropriately opposed to the gripping surface 32A. The contact surface 32B is formed in a form extending along the opening / closing direction of the claw portion 30. The knob surface 32A and the contact surface 32B are formed so as to cross each other.

  A communication path 31 </ b> A communicating with the space S is formed in the upper part of the claw body 31. The communication passage 31 </ b> A is connected to a compressed air supply unit (not shown) and supplies compressed air to the space S. The compressed air supply means can include an air tube, a tube joint, a pair of couplers, and the like. The compressed air supply means is configured such that, for example, one of the pair of couplers is disposed in the drive unit 10 and the other is disposed in the main body unit 20, so that the pair of couplers can be attached and detached by attaching and detaching the drive unit 10 and the main body unit 20. Can be used.

<Transmitter 40>
As illustrated in FIGS. 4 and 7, the transmission unit 40 includes a first driven unit 41 and a second driven unit 42. The first follower 41 is transmitted with the movement of the drive unit 10. The first driven portion 41 rotates around a predetermined rotation axis A1 to cause one of the two claw portions 30 to interlock and grip the workpiece W. The second driven portion 42 meshes with the first driven portion 41. The movement of the driving unit 10 is transmitted to the second driven unit 42 via the first driven unit 41. The second follower 42 rotates around another predetermined rotation axis A2 different from the first follower 41, thereby causing the other of the two claw portions 30 to interlock and grip the workpiece W.

  Specifically, the first driven portion 41 includes a first driven shaft 41A, a first driven gear 41B, a first rack 41C, a first guide unit 41D, and a first transmission gear 41E. The first driven shaft 41 </ b> A is rotatably supported at both axial ends by bearings 43 fitted in the case members 21 and 22 before and after the main body portion 20. The first driven shaft 41 </ b> A is arranged in a form that is parallel to the axial direction of the drive shaft 13 </ b> A of the motor 13 in a state where the main body 20 is connected to the drive unit 10. The first driven gear 41B is fixed to the first driven shaft 41A. The first driven gear 41B meshes with the drive gear 14 of the drive unit 10 when the drive unit 10 and the main body unit 20 are connected. Thus, the first driven gear 41B rotates following the rotation of the drive gear 14. The first rack 41C is provided below the first driven gear 41B and meshes with the first driven gear 41B, and is connected to the first guide unit 41D and is movable in the left-right direction. The first rack 41C moves in the left-right direction while being guided by the first guide unit 41D by the rotation of the first driven gear 41B. The first guide unit 41D is a so-called linear guide unit including a guide rail and a block that linearly moves on the guide rail. In the first guide unit 41D, the guide rail is connected and fixed to the first rack 41C, and the block is fixed to the case member 21. One of the two claw portions 30 is fixed to the guide rail in the first guide unit 41D. The first transmission gear 41E is disposed on the front side of the first driven gear 41B and is fixed to the first driven shaft 41A, and rotates with the rotation of the first driven gear 41B. The first transmission gear 41E meshes with a second transmission gear 42E of a second driven portion 42 described later.

  The second driven portion 42 includes a second driven shaft 42A, a second driven gear 42B, a second rack 42C, a second guide unit 42D, and a second transmission gear 42E. The second driven shaft 42A is arranged on the left side of the first driven shaft 41A in parallel with the first driven shaft 41A. Similarly to the first driven shaft 41A, the second driven shaft 42A is rotatably supported by the case members 21 and 22 of the main body 20 at both ends in the axial direction. The second driven gear 42B is fixed to the second driven shaft 42A. The second driven gear 42B is a gear having the same number of teeth and the same PCD as the first driven gear 41B. The second driven gear 42B is disposed rearward in the axial direction with respect to the first driven gear 41B, and meshes with the second rack 42C disposed below the second driven gear 42B. The second rack 42C and the second guide unit 42D have substantially the same configuration as the first rack 41C and the first guide unit 41D, respectively. In the second rack 42C, the guide rail is connected and fixed to the second rack 42C and the block is fixed to the case member 22 by the rotation of the second driven gear 42B. In the second guide unit 42D, the other of the two claw portions 30 is fixed to the guide rail. The second transmission gear 42E is disposed on the front side of the second driven gear 42B and is fixed to the second driven shaft 42A. The second transmission gear 42E meshes with the first transmission gear 41E of the first driven portion 41, and rotates with the rotation of the first transmission gear 41E. The second transmission gear 42E is a gear having the same number of teeth and the same PCD as the first transmission gear 41E.

<Magnetic force generation part 50>
In the gripping device 1 according to this embodiment, each of the two claw portions 30 includes a magnetic force generation unit 50. The magnetic force generator 50 is provided on the back side of the contact surface 32B and generates a magnetic force in the front direction of the contact surface 32B (the lower end direction of the claw portion 30). In the present embodiment, the magnetic force generator 50 is arranged in the space S inside the claw body 31. Specifically, as shown in FIG. 6, the magnetic force generator 50 includes a piston 51, a permanent magnet 52, and a coil spring 53. The piston 51 has a cylindrical shape having an outer diameter slightly smaller than the inner diameter of the claw body 31, and is disposed so as to be movable in the axial direction along the inner peripheral surface of the claw body 31 via a seal member 51A. . The permanent magnet 52 has a cylindrical shape having an outer diameter smaller than the outer diameter of the piston 51. The permanent magnet 52 is provided on the back side of the contact surface 32B so as to be able to advance and retract toward the contact surface 32B. Specifically, the permanent magnet 52 is connected to the lower end of the piston 51 coaxially with the piston 51 and is provided so as to be movable in the axial direction as the piston 51 moves in the axial direction. The permanent magnet 52 is disposed in the claw body 31 in a form in which a gap is formed between the outer peripheral surface thereof and the inner peripheral surface of the claw body 31. The coil spring 53 is a compression spring. The coil spring 53 imparts an elastic force to the permanent magnet 52 in a direction away from the contact surface 32B. Specifically, the upper end of the coil spring 53 is in contact with the lower surface of the piston 51, and the permanent magnet 52 is inserted into the inner periphery of the upper end portion, and is disposed below the piston 51. The coil spring 53 imparts an elastic force that acts on the piston 51 in the upward direction. As a result, the permanent magnet 52 is given an elastic force in a direction away from the contact surface 32 </ b> B by the coil spring 53, which is an elastic member, via the piston 51.

  Further, the magnetic force generator 50 supplies the compressed air to the space S above the piston 51 via the communication passage 31A of the claw body 31, thereby moving the piston 51 downward against the elastic force of the coil spring 53. The permanent magnet 52 can be moved close to the contact surface 32B of the grip portion 32. In this state, the magnetic force of the permanent magnet 52 acts in the front direction of the contact surface 32B. When the supply of compressed air is stopped, the piston 51 returns upward due to the elastic force of the coil spring 53. In this state, the magnetic force of the permanent magnet 52 acting in the front direction of the contact surface 32B is reduced. The permanent magnet 52 is disposed in the claw body 31 in a form that forms a gap between the permanent magnet 52 and the inner circumferential surface of the claw body 31, thereby suppressing the generation of magnetic force on the outer circumferential surface side of the claw body 31. ing.

Next, the operation of the gripping device 1 configured as described above will be described.
The gripping device 1 is used for picking an annular workpiece W. The gripping device 1 is used by replacing the main body 20 having different claw portions 30 suitable for each workpiece W with respect to a plurality of types of workpieces W having different diameters and thicknesses.

  When replacing the main body 20, first, the main body 20 that is currently attached is removed from the drive unit 10. Specifically, first, the left and right brackets 27 of the main body 20 are respectively moved outward. At this time, a jig (not shown) is inserted into the insertion holes 27A of the left and right brackets 27 from the front or rear, and is moved evenly in the left-right direction. Thereby, each lock pin 24 and 25 is engaged / disengaged from the through-hole 12 </ b> B of the guide bush 12. Then, when the driving unit 10 and the main body 20 are relatively moved along the extending direction of the groove 23 </ b> A of the slide member 23, the main body 20 is removed from the driving unit 10. Thereby, the meshing | engagement with the drive gear 14 of the 1st driven part 41 is cancelled | released, and the mechanical connection of the drive part 10 and the transmission part 40 is cancelled | released. In this state, on the drive unit 10 side, the state where the drive unit 10 is coupled to the arm 110 of the robot 100 is maintained, so that the electrical connection with the power source of the motor 13 is maintained. Thus, when the main body 20 is replaced, it is not necessary to release and reconnect the electrical connection of the motor 13 with a connector or the like. On the main body 20 side, the claw portion 30 and the transmission portion 40 are integrally removed. Thereby, the synchronized state of the two claw portions 30 is also maintained. Specifically, when the main body 20 is removed from the drive unit 10, the engagement between the first driven gear 41B of the transmission unit 40 on the main body 20 side and the drive gear 14 on the drive unit 10 side is released. However, the engagement of the gears and the rack in the transmission part 40 on the main body part 20 side is maintained, and synchronization between the two claw parts 30 interlocking with the first driven part 41 and the second driven part 42 is also maintained. ing.

When attaching the main body 20 to the drive unit 10, first, the left and right brackets 27 are expanded outward and the lock pins 24 and 25 are buried in the slide member 23. In this state, the guide bush 12 of the drive unit 10 is slid along the groove 23A of the slide member 23 of the main body unit 20 to move the main body unit 20 and the drive unit 10 relative to each other. The first driven gear 41B is engaged with the drive gear 14 of the drive unit 10. Finally, the force of expanding the left and right brackets 27 outward is released, and the lock pins 24 and 25 are engaged with the through holes 12B of the guide bush 12.
In addition, when the attachment of the main body 20 to the driving unit 10 is completed, the two claw portions 30 are driven in the direction in which the two claw portions 30 are brought close to each other (the direction in which the claw is closed) to be brought into the closest state. Alignment from the central axis C is performed.

  When picking the workpiece W, the motor 13 of the drive unit 10 is driven, and the rotational motion is transmitted to the claw unit 30 via the transmission unit 40, whereby the workpiece W is gripped by each of the two claw units 30. Let A specific motion transmission path from the motor 13 to the claw portion 30 is as follows.

  The drive of the motor 13 is transmitted to the first driven gear 41B of the first driven portion 41 by rotating the drive gear 14 by the rotation of the drive shaft 13A. That is, as shown in FIG. 4, the drive gear 14 meshes with the first driven gear 41 </ b> B in a state where the main body 20 is attached to the drive unit 10, and the rotation is transmitted to the first driven unit 41. . The second driven portion 42 does not mesh directly with the drive gear 14. However, the second driven portion 42 has the second transmission gear 42E meshed with the first transmission gear 41E. Therefore, the rotation of the drive gear 14 is transmitted to the second driven portion 42 via the first driven portion 41. Therefore, when the motor 13 is driven, the rotational motion is transmitted to both the first driven portion 41 and the second driven portion 42 of the transmission portion 40.

  The two claw portions 30 are connected to the first rack 41C of the first driven portion 41 and the second rack 42C of the second driven portion 42, respectively. Since the first rack 41C and the second rack 42C mesh with the first driven gear 41B and the second driven gear 42B, respectively, the two claw portions 30 move in synchronization with each other with respect to the central axis C. . Specifically, as described above, the second transmission gear 42E has the same PCD as the first transmission gear 41E. For this reason, when the rotation of the first transmission gear 41E is transmitted, the second transmission gear 42E rotates at a rotation ratio of 1: 1 with respect to the first transmission gear 41E. Further, when the second transmission gear 42E and the first transmission gear 41E rotate at a rotation ratio of 1: 1, the second driven portion 42 rotates when the second driven portion 42 rotates about the rotation axis A2. To a rotation ratio of 1: 1 with respect to the rotation around the rotation axis A1. Further, as described above, the second driven gear 42B and the first driven gear 41B have the same PCD. For this reason, when the power from the drive gear 14 is transmitted to the first driven gear 41B and rotates, the second driven gear 42B rotates at a rotation ratio of 1: 1 with respect to the first driven gear 41B. When the second driven unit 42 rotates about the rotation axis A2 and the first driven unit 41 rotates about the rotation axis A1, the second driven gear 42B and the first driven gear 41B rotate at a rotation ratio of 1: 1. Therefore, the first rack 41C and the second rack 42C meshed with the first driven gear 41B and the second driven gear 42B, respectively, and the respective claw portions 30 respectively connected to the first rack 41C and the second rack 42C It moves symmetrically with the same speed with respect to the axis C. In this way, the rotational movement of the motor 13 is transmitted to the two claw portions 30, and the two claw portions 30 move to grip the workpiece W.

  Note that the gripping state of the gripping device 1 is performed by the driver measuring the magnitude of the current value flowing through the motor 13. Further, the motor 13 is driven by feedback control in which the magnitude of the supplied current value is determined by comparison with the threshold value of the current value of the motor 13 by the driver.

  In the present embodiment, the magnetic force generator 50 is used when the workpiece W is picked. Specifically, as shown in FIG. 8A, first, the gripping device 1 is moved by the robot 100 so that the center axis C of the gripping device 1 is coaxial with the center axis Cw of the workpiece W. . In the case of this embodiment, the workpiece W is conveyed on the belt conveyor B. The position of the workpiece W is grasped by a phase shift method using a scanner, a projector or the like (not shown), and the grasping device 1 is moved so that the center axis C is aligned with the center axis Cw of the grasped workpiece W. Let

  Next, as illustrated in FIG. 8B, the gripping device 1 is lowered to bring the upper surface of the workpiece W into contact with the contact surface 32 </ b> B of the gripping portion 32. At this time, compressed air is supplied into the space S of the claw body 31 by the compressed air supply means, and the permanent magnet 52 is lowered and advanced to the back surface of the abutting surface 32B. Then, the magnetic force of the permanent magnet 52 acts on the core of the workpiece W, the workpiece W is attracted to the grip portion 32, and the upper surface of the workpiece W is brought into contact with the contact surface 32B. In this state, the motor 13 of the drive unit 10 is driven to move the claw portion 30 to grip the workpiece W, whereby the outer peripheral surface of the workpiece W is reliably brought into contact with the gripping surface 32A of the gripping portion 32 and gripped. be able to. Further, the knob surface 32A is formed in a V shape, and preferably comes into contact with the outer peripheral surface of the workpiece W which is a circumferential surface portion.

  And the holding | grip apparatus 1 is raised and the workpiece | work W is conveyed to a desired position. As shown in FIG. 8C, after the outer peripheral surface of the workpiece W is gripped by the gripping surface 32A of the gripping portion 32, the permanent magnet 52 is raised. Since the elastic force of the coil spring 53 is applied via the piston 51, the permanent magnet 52 automatically rises by stopping the supply of compressed air into the space S and reducing the internal pressure. Further, from the viewpoint of suppressing the magnetism of the cored bar, which is the magnetic body portion of the work W, the permanent magnet 52 is moved at an earlier timing after the knob surface 32A comes into contact with the outer peripheral surface of the work W and securely holds the work W. It is preferable to raise the distance from the contact surface 32B.

  Next, the case of picking a workpiece tilted by the gripping device 1 will be described. Since the gripping device 1 is attached to the arm 110 of the six-axis robot 100, the center axis can be aligned with the center axis of the workpiece following the tilt of the workpiece. For this reason, the gripping device 1 can perform the picking preferably following the relatively large inclination of each workpiece when, for example, picking a plurality of workpieces randomly stored in the return box individually. On the other hand, when gripping a workpiece W2 having a relatively small inclination, for example, a slight inclination due to burrs or the like during molding, as shown in FIG. Gripping can be realized.

  Specifically, as shown in FIG. 9A, first, the gripping device 1 is moved and lowered by the robot 100 in accordance with the workpiece W2 whose position has been grasped. At this time, as shown in FIG. 9B, since the workpiece W2 is slightly inclined on the conveying surface of the belt conveyor B due to burrs at the time of molding, the center axis Cw of the workpiece W2 and the center of the gripping device 1 are formed. There is an inclination with respect to the axis C. For this reason, the contact | abutting with the contact surface 32B of the holding part 32 and the upper surface of the workpiece | work W2 has arisen. If an attempt is made to grip the workpiece W2 in this state, there is a possibility that the gripping surface 32A cannot be reliably gripped because the engagement of the gripping surface 32A on the outer peripheral surface of the workpiece W2 is shallow. In this embodiment, the permanent magnet 52 of the magnetic force generation unit 50 is lowered in this state and moved to the back surface of the contact surface 32B of the grip portion 32. Then, as shown in FIG. 9C, the magnetic force of the permanent magnet 52 acts on the core of the work W2 to attract the work W2 to the grip portion 32, and the upper surface of the work W2 comes into contact with the contact surface 32B. In this state, the motor 13 of the drive unit 10 is driven to move the claw portion 30 to grip the workpiece W, whereby the outer peripheral surface of the workpiece W is reliably brought into contact with the gripping surface 32A of the gripping portion 32 and gripped. be able to.

  As described above, the gripping device 1 according to the first embodiment is a device that grips the workpiece W by including the two claw portions 30 that are provided so as to be freely opened and closed. In the gripping device 1, a plurality of claw portions 30 includes a gripping portion 32 and a magnetic force generation portion 50. A gripping surface 32A and a contact surface 32B are formed on the grip portion 32. The knob surface 32A is formed in a form facing the opening / closing direction. The contact surface 32B is formed in a form extending along the opening and closing direction. The gripping part 32 brings the gripping surface 32 </ b> A and the contact surface 32 </ b> B into contact with the work W when gripping the work W. The magnetic force generator 50 is provided on the back side of the contact surface 32B and generates a magnetic force in the front direction of the contact surface 32B.

  With such a configuration, the gripping device 1 generates a magnetic force toward the front surface of the contact surface 32 </ b> B by the magnetic force of the magnetic force generation unit 50. For this reason, the magnetic workpiece W can be attracted to and brought into contact with the contact surface 32B, which is a surface different from the knob surface 32A. As a result, the position and posture of the workpiece W can be regulated using the contact surface 32B as a reference surface, so that the gripping operation of the plurality of claw portions 30 is performed while the workpiece W is in contact with the contact surface 32B. The surface 32A can be held in contact with a desired position of the workpiece W.

  Therefore, the gripping device 1 can securely grip the workpiece W.

  Moreover, the magnetic force generation part 50 has the permanent magnet 52 provided in the back side of the contact surface 32B so that it can advance and retract toward the contact surface 32B. For this reason, the magnetic force of the magnetic force generation part 50 can be made to act only when desired. Thereby, it can prevent attracting the workpiece | work W unintentionally.

  Moreover, the magnetic force generation unit 50 includes a coil spring 53 as an elastic member that applies an elastic force in a direction in which the permanent magnet 52 is separated from the contact surface 32B. For this reason, the mechanism in which the permanent magnet 52 advances and retreats with respect to the contact surface 32B can be realized with a simple configuration.

  Moreover, the workpiece | work W has the outer peripheral surface as a circumferential surface part. The knob surface 32A is formed in a V-shape. For this reason, the picking surface 32A can be reliably brought into contact with the workpiece W having the circumferential surface portion, and the workpiece W can be reliably gripped.

The present invention is not limited to the first embodiment described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In Embodiment 1, although the form which provides two claw parts as a some nail | claw part was illustrated, it is good also as a form which provides three or more claw parts.
(2) In the first embodiment, as the movement for gripping the workpiece, the form in which the plurality of claw parts move linearly in parallel is exemplified. However, the form in which the claw parts rotate around a predetermined axis and the rotation by the link mechanism are exemplified. Other forms such as a form in which movement and linear movement are combined may be used.
(3) In Embodiment 1, although the form which grips the outer peripheral surface of a workpiece | work by moving a some nail | claw part to the direction which mutually adjoins was illustrated, the grip form of a workpiece | work is not limited to this. For example, in the case of a ring-shaped workpiece, the workpiece may be gripped in another form, such as gripping the inner peripheral surface by moving a plurality of claw portions in directions away from each other.
(4) In Embodiment 1, a pin seal having an annular shape is exemplified as the workpiece, but the shape of the workpiece is not particularly limited. The gripping device of the present invention can also grip a workpiece that does not have magnetism.
(5) In Embodiment 1, although the form provided with the drive part and main part which were provided detachably was illustrated, it is good also as a form where the drive part and the main part were provided integrally.
(6) In Embodiment 1, although the form which provides a magnetic force generation part in all the some nail | claw parts was illustrated, it is good also as a form which provides a magnetic force generation part in 1 or 2 or more of a some nail | claw parts.
(7) In the first embodiment, the form in which the magnetic force generator has a permanent magnet is exemplified, but a magnetic force generator using an electromagnet may be used.
(8) In the first embodiment, the form in which the knob surface is formed in a V shape is illustrated, but this is not essential. As the shape of the knob surface, a shape corresponding to the workpiece can be appropriately adopted.

  DESCRIPTION OF SYMBOLS 1 ... Gripping device, 10 ... Drive part, 11 ... Base (11A ... Upper part, 11B ... Front wall part, 11C, 11D ... Side wall part), 12 ... Guide bush (12A ... Flange part, 12B ... Through-hole), 13 ... Motor, 13A ... drive shaft, 14 ... drive gear, 20 ... main body, 21,22 ... case member, 23 ... slide member, 23A ... groove, 23B ... tapered surface, 24,25 ... lock pin, 26 ... coil spring, 27 ... Bracket, 27A ... Insertion hole, 30 ... Claw part, 31 ... Claw body, 31A ... Communication path, 32 ... Gripping part, 32A ... Picking surface, 32B ... Abutment surface, 40 ... Transmission part, 41 ... First driven part , 41A ... first driven shaft, 41B ... first driven gear, 41C ... first rack, 41D ... first guide unit, 41E ... first transmission gear, 42 ... second driven portion, 42A ... second driven shaft, 42B ... Second driven gear 42C ... second rack, 42D ... second guide unit, 42E ... second transmission gear, 43 ... bearing, 50 ... magnetic force generator, 51 ... piston, 51A ... sealing member, 52 ... permanent magnet, 53 ... coil spring, 100 ... Robot, 110 ... Arm, A1, A2 ... Rotating axis of driven part, B ... Belt conveyor, C ... Center axis of gripping device, Cw ... Center axis of workpiece, S ... Space in nail body, W, W2 ... Workpiece

Claims (4)

A gripping device that grips a workpiece with a plurality of claw portions that are freely opened and closed,
The plurality of claws are
A gripping surface in a form facing the opening / closing direction and a contact surface extending in the opening / closing direction are formed, and a gripping part for bringing the gripping surface and the contact surface into contact with the work when gripping the workpiece; ,
A magnetic force generator provided on the back side of the contact surface and generating a magnetic force toward the front direction of the contact surface;
Each of which is provided with a gripping device.   The gripping apparatus according to claim 1, wherein the magnetic force generation unit includes a permanent magnet that is provided on the contact surface so as to freely advance and retract.   The gripping device according to claim 2, wherein the magnetic force generation unit includes an elastic member that applies an elastic force in a direction in which the permanent magnet is separated from the contact surface.   The gripping device according to any one of claims 1 to 3, wherein the knob surface is formed to be recessed in a V shape.

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