JP2015231652A - Robot hand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot hand capable of surely gripping a workpiece.SOLUTION: A robot hand comprises: a motor 17 having a rotation shaft 16; plural claw parts 13 for gripping a workpiece W; and a transmission part 22 disposed on a motion transmission path where rotational motion of the motor 17 is converted into motion which the claw parts 13 grip the workpiece W. The transmission part 22 comprises drive side magnets 20 to which the rotation shaft 16 of the motor 17 is coupled and which rotate, and passive side magnets 21 disposed corresponding to each of the claw parts 13 in the vicinity of the drive side magnet 20, and to which rotational force of the drive side magnet 20 is transmitted by magnetic force and which rotate.

Description

  The present invention relates to a robot hand.

  Patent Document 1 discloses a conventional robot hand. The robot hand includes a motor having a rotation shaft, a plurality of claw portions that grip a workpiece, and first to third conversion mechanisms. The first conversion mechanism has a worm and a worm wheel. The first conversion mechanism converts rotation about the horizontal axis of the motor into rotation about the vertical axis of the worm wheel. The second conversion mechanism has a cylindrical portion and a shaft. The second conversion mechanism screwes the tube portion and the shaft, and converts the rotation of the worm wheel about the vertical axis into linear movement of the shaft in the vertical axis direction. The third conversion mechanism has a support base, a support part, and a claw support part. The third conversion mechanism converts the linear movement of the shaft in the vertical axis direction into a radial linear movement of the virtual circle of the claw support portion. Thereby, the claw part fixed to the claw support part via the connecting part linearly moves in the radial direction. Thus, this robot hand can convert the rotation of the motor around the horizontal axis into the linear movement of the claw portion in the radial direction.

JP 2012-171034 A

  However, in the robot hand of Patent Document 1, since the motor and each claw portion are mechanically connected via a worm or the like, and each claw portion is interlocked by driving the motor, each claw portion has the same distance in the radial direction. Move straight. For this reason, even when a part of the claw portion comes into contact with the workpiece, such as when trying to grip a misaligned workpiece, the other claw portion may not come into contact with the workpiece. That is, this robot hand may not be able to grip a workpiece.

  The present invention has been made in view of the above-described conventional situation, and an object to be solved is to provide a robot hand that can reliably hold a workpiece.

The robot hand of the present invention includes a motor having a rotation axis,
A plurality of claws for gripping the workpiece;
A robot hand provided with a transmission portion provided in a motion transmission path for converting the rotational motion of the motor into a motion in which the claw portion grips a workpiece,
The transmission unit is
A drive-side magnet that is connected to the rotating shaft of the motor and rotates;
A passive side magnet that is disposed in the vicinity of the driving side magnet corresponding to each of the claw portions, and a rotational force of the driving side magnet is transmitted by a magnetic force to rotate,
It is characterized by having.

  This robot hand transmits the rotational force of the motor to the claw portion via a transmission portion having a drive side magnet and a passive side magnet arranged corresponding to each claw portion in the vicinity of the drive side magnet. The driving side magnet and the passive side magnet can transmit the rotational force within the range attracted by the magnetic force even if the rotational direction shift occurs. For this reason, even if the claw portion is in contact with the workpiece and the rotation of the passive magnet is restricted, the transmission of the rotational force can be maintained within a predetermined rotation range even if the driving magnet continues to rotate. Therefore, this robot hand maintains the transmission of the rotational force of the motor to the claw portion that has previously contacted the workpiece when the plurality of claw portions do not contact the workpiece at the same time because the workpiece is misaligned. Meanwhile, the claw portion that is not in contact with the workpiece can be brought into contact with the workpiece.

  Therefore, the robot hand of the present invention can securely hold the workpiece.

It is a side view which shows the robot with the robot hand of Example 1. FIG. 1 is a side sectional view showing a robot hand of Example 1. FIG. It is arrow XX sectional drawing shown in FIG. It is the side view seen from the arrow Y direction shown in FIG. FIG. 2 is a side view of the robot hand according to the first embodiment, and (B) is a perspective view illustrating a magnetized form of each magnet. BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows the state which the robot hand of Example 1 hold | gripped the workpiece | work, Comprising: (A) shows the state which makes a nail | claw part contact | abut on the internal peripheral surface which an annular | circular shaped workpiece | work with a large internal diameter contacts. , (B) shows a state in which a claw portion is brought into contact with and grips an opposing inner circumferential surface of an annular workpiece having a small inner diameter, and (C) shows a claw between the outer circumferential surface and the inner circumferential surface of the annular workpiece. It shows a state of gripping with the part. It is a side view which shows the state which the workpiece | work contact | abutted on the nail | claw part on the left side, when the robot hand of Example 1 hold | grips the workpiece | work which position shifted. FIG. 5 is a side view showing a state in which a claw portion is brought into contact with and gripped by an opposing inner peripheral surface of an annular workpiece having a large inner diameter, following a workpiece in which the robot hand of Example 1 is tilted. It is the side view in which the robot hand of Example 1 contacted the obstruction, (A) shows the state where the front-end | tip of the right nail | claw part contacted the obstruction, (B) shows the front-end | tip part of the right nail | claw part. The outer surface shows a state in contact with the obstacle, and (C) shows a state in which the rear side surface of the tip portion of the right claw is in contact with the obstacle. It is a robot hand of Example 2, Comprising: (A) is a side view, (B) is a perspective view which shows the form of magnetization of each magnet.

  Next, Example 1 or 2 that embodies the robot hand of the present invention will be described with reference to the drawings.

<Example 1>
The robot hand according to the first embodiment is attached to the tip of the arm of the 6-axis robot 94 as shown in FIG. The robot hand includes a robot hand body 10, a pair of two drive links 11, a pair of driven links 12, a pair of claw portions 13, and a motor driver 14. 2 and 3, the robot hand body 10 includes a case 15, a motor 17 having a rotation shaft 16, a screw gear 18, a drive shaft 53, a drive screw gear 19, and a drive-side magnet 20. . The drive link 11 has a passive magnet 21. The drive-side magnet 20 and the passive-side magnet 21 constitute a transmission unit 22 that transmits rotational force.

  The case 15 has a substantially rectangular parallelepiped long in the left-right direction, and includes an upper surface 23, a lower surface 24, a front side surface 25, a rear side surface 26, a left side surface 27, a right side surface 28, a left inclined surface 29, and a right inclined surface 50 ( Up, down, left, and right refer to the top, bottom, left, and right in FIG. The left and right inclined surfaces 29 and 50 are formed by cutting out the boundary portions between the left and right side surfaces 27 and 28 and the lower surface 24. The case 15 has an opening at the center of the upper surface 23. The case 15 has a first space 51 into which the rotating shaft 16 of the motor 17 and the screw gear 18 described later are inserted from the opening of the upper surface 23. The case 15 has a pair of second space portions 52 penetrating from the front side surface 25 to the rear side surface 26 and formed on the left and right sides of the first space portion 51. The second space 52 accommodates a drive shaft 53, a drive screw gear 19 and a drive side magnet 20, which will be described later. As shown in FIG. 2, the case 15 is a corner where the upper surface 23 intersects with the left and right side surfaces 27 and 28, and a third shaft member 54 extends in the front-rear direction at the center in the front-rear direction. The third shaft member 54 is inserted into a hole of a third joint portion 55 of each driven link 12 described later, and pivotally supports each driven link 12.

  As for the screw gear 18, the rotating shaft 16 of the motor 17 is inserted in the center shaft hole. The screw gear 18 is fixed to the rotating shaft 16 of the motor 17 and rotates together. The screw gear 18 has helical teeth formed on the outer peripheral surface. The motor 17 is fixed to the center of the upper surface 23 of the case 15 in a state where the rotating shaft 16 and the screw gear 18 are housed in the first space 51 of the case 15.

  As shown in FIG. 3, the drive shaft 53 includes a columnar shaft portion and disk-shaped flange portions 91 having outer diameters larger than the outer diameter of the shaft portion at both ends of the shaft portion. In the drive screw gear 19, the central portion of the shaft portion of the drive shaft 53 is inserted into the central shaft hole. The drive screw gear 19 is fixed to the drive shaft 53 and rotates together. The drive screw gear 19 has helical teeth on the outer peripheral surface.

  The drive side magnet 20 has a cylindrical shape (ring shape). The drive-side magnet 20 is fixed by abutting the inner end face on each of the outer faces of the flanges 91 provided at both ends of each drive shaft 53. The drive side magnet 20 is arranged coaxially with the drive shaft 53. The drive-side magnet 20 is alternately magnetized with a north pole and a south pole every 45 degrees in the circumferential direction (see FIG. 5B).

  The case 15 accommodates one unit of the drive shaft 53, the drive screw gear 19, and the drive side magnet 20 one by one in each of the pair of second space portions 52 formed on the left and right sides of the first space portion 51. ing. In this state, each drive shaft 53 and the rotation shaft 16 of the motor 17 are orthogonal to each other, the screw gear 18 fixed to the rotation shaft 16 of the motor 17, and the drive screw gear fixed to the shaft portion of the drive shaft 53. 19 is engaged. In this way, the drive-side magnet 20 can rotate with the rotation shaft 16 of the motor 17 connected thereto. Each drive-side magnet 20 has an outer end surface exposed at a front opening 57 formed on the front side surface 25 of the second space 52 or a rear opening 96 formed on the rear side surface 26.

  As shown in FIGS. 2 to 5A, each drive link 11 includes a node 58, a disk-shaped first joint 60 formed on one end of the node 58, and the other end of the node. The second joint portion 61 is formed. The first joint portion 60 forms a concave portion 62 whose side surface facing the case 15 is rolled into a disk shape. The first joint portion 60 houses and fixes the passive magnet 21 in the recess 62. The passive-side magnet 21 has the same cylindrical shape (ring shape) as the driving-side magnet 20. The passive-side magnet 21 is alternately magnetized at 45 degrees in the circumferential direction at N and S poles (see FIG. 5B).

  The first joint portion 60 of each drive link 11 has an outer end surface of the drive-side magnet 20 whose inner end surface of the passive-side magnet 21 housed in the recess 62 is exposed to the front opening 57 or the rear opening 96 of the case 15. It arrange | positions so that it may contact | abut. That is, the passive magnet 21 and the driving magnet 20 are in contact with each other because the attracting poles are magnetized. This part corresponds to the transmission part 22 of the robot hand. Since each drive link 11 can be attracted by a magnetic force if the deviation between the drive-side magnet 20 and the passive-side magnet 21 is within a predetermined rotation range, it does not fall off.

  As shown in FIG. 4, the node portion 58 of each drive link 11 extends from a part of the outer surface of the first joint portion 60 so as to be inclined below the case 15 and toward the front and rear central portion. The 2nd joint part 61 has the hole penetrated in the front-back direction. In this manner, two pairs of drive links 11 disposed in front of and behind the case 15 are disposed symmetrically about the rotating shaft 16 of the motor 17.

  As shown in FIGS. 2 and 4, each driven link 12 includes a joint 59, a third joint 55 formed on one end of the joint 59, and a second joint formed on the other end of the joint 59. 4 joint portions 56. The node portion 59 has an arc shape that bulges outward. The 3rd joint part 55 and the 4th joint part 56 have the hole penetrated in the front-back direction. As described above, in the third joint portion 55, the third shaft member 54 at the corner where the upper surface 23 of the case 15 intersects with the left and right side surfaces 27 and 28 passes through the hole portion. As described above, the pair of driven links 12 are arranged at the symmetrical positions of the case 15.

  The claw portion 13 includes a claw body 63 and a pair of link plates 64 that sandwich the upper end portion of the claw body 63 from the front-rear direction. The nail | claw main body 63 is extended in the up-down direction, and a horizontal cross-sectional shape is a rectangular shape. Each link plate 64 has a long piece portion 65 that overlaps the front and rear side surfaces of the claw body 63 and a short piece portion 66 that extends from the upper end of the long piece portion 65 outward in the left-right direction. Each link plate 64 has a long piece 65 fixed to the front and rear side surfaces of the claw body 63. The claw portion 13 has a first shaft insertion hole 67 penetrating in the front-rear direction under the long piece portion 65 of the pair of link plates 64 sandwiching the claw body 63. Further, the claw portion 13 has a second shaft insertion hole 68 that penetrates at a position away from the long piece portion 65 of the short piece portion 66 of the pair of link plates 64.

  A portion of the claw portion 13 that penetrates the first shaft insertion hole 67 is sandwiched between the second joint portions 61 of the pair of drive links 11 from the front-rear direction. In this state, the first shaft insertion hole 67 of the claw portion 13 communicates with the hole of the second joint portion 61 of the drive link 11, and the first shaft member 69 is connected to the first shaft insertion hole 67 and the second joint portion 61. The hole is inserted through the hole and is rotatably connected. Further, the claw portion 13 sandwiches the fourth joint portion 56 of the driven link 12 from the front-rear direction by a portion of the link plate 64 penetrating the second shaft insertion hole 68. In this state, the second shaft insertion hole 68 of the claw portion 13 communicates with the hole of the fourth joint portion 56 of the driven link 12, and the second shaft member 95 is connected to the second shaft insertion hole 68 and the fourth of the driven link 12. The joint portion 56 is rotatably connected through the hole.

  In this way, the pair of claw portions 13 are arranged symmetrically about the rotation shaft 16 of the motor 17. The pair of claw portions 13 are positioned so that the opposing surfaces of the left and right claw bodies 63 are substantially parallel. The right and left nail main bodies 63 have urethane sheets 90 attached to the lower ends of the opposing surfaces. The robot hand forms a link mechanism by the drive link 11, the follower link 12, and the claw portion 13.

  Next, a motion transmission path from the motor 17 to the claw portion 13 will be described. The rotational force of the motor 17 is applied to the left and right via the screw gear 18 in which the rotation shaft 16 of the motor 17 is coaxially inserted and fixed, and the drive screw gear 19 coaxially fixed to the central portion of the drive shaft 53. It is transmitted to the drive shaft 53. The pair of drive shafts 53 rotate symmetrically about the rotation shaft 16 of the motor 17. The drive-side magnets 20 that are coaxially fixed to the outer surfaces of the flanges 91 provided at both ends of the respective drive shafts 53 rotate together with the respective drive shafts 53. The drive link 11 is magnetically attached to the drive side magnet 20 via the passive side magnet 21 fixed to the recess 62 formed in the first joint portion 60, and the rotation shaft 16 of the motor 17 together with the left and right drive shafts 53. Rotate symmetrically around the center (transmission unit 22). At this time, when the second joint portions 61 of the left and right drive links 11 rotate in directions away from each other, the left and right claw portions 13 are separated from each other while being translated in the left-right direction by the link mechanism. Further, when the second joint portions 61 of the left and right drive links 11 rotate in a direction approaching each other, the left and right claw portions 13 approach each other while being translated in the left-right direction by the link mechanism. Thus, as shown in FIGS. 6A to 6C, the robot hand can grip the workpiece from either the outer peripheral surface or the inner peripheral surface of the workpiece.

  As shown in FIG. 1, the motor driver 14 is connected to the motor 17 via a signal line 92. The motor driver 14 reads the current value flowing through the motor 17 via the signal line 92, compares the current value with a threshold value, and determines the current value to be supplied to the motor 17. That is, the motor driver 14 measures the current value of the motor 17, recognizes the gripping state of the robot hand, and determines the current value to the motor 17 so that the robot hand grips the workpiece reliably. I am doing.

  As shown in FIG. 7, the robot hand is driven in a state where the workpiece W is displaced, only the left claw portion 13 is in contact with the workpiece W, and the rotation of the left passive magnet 21 is restricted. Even if the side magnet 20 continues to rotate, transmission of rotational force can be maintained within a predetermined rotation range. For this reason, when the left and right claw portions 13 are not in contact with the workpiece W at the same time, the robot hand maintains the transmission of the rotational force of the motor 17 to the claw portion 13 that has previously contacted the workpiece W. The claw portion 13 that is not in contact with the workpiece W can be brought into contact with the workpiece W.

Therefore, the robot hand according to the first embodiment can reliably hold the workpiece W.

  Further, as shown in FIG. 6A, the robot hand can hold the claw portion 13 in contact with the inner peripheral surface of a large annular workpiece W1. Further, as shown in FIG. 6B, the robot hand can hold the claw portion 13 in contact with the inner peripheral surface of a small annular workpiece W2. In addition, as shown in FIG. 6C, the robot hand can hold the outer peripheral surface and the inner peripheral surface of the annular workpiece W2 with the claw portion 13 therebetween. In addition, as shown in FIG. 8, the robot hand can grip the workpiece W3 by following the tilt of the workpiece W3 by the arm of the six-axis robot 94 when the workpiece W3 is tilted.

  9A, when the robot hand is lowered and the tip of the right claw 13 hits an obstacle 93, the right passive magnet 21 is driven by the drive magnet 20. It is possible to avoid the deformation and breakage of the claw portion 13. In addition, as shown in FIG. 9B, when the robot hand moves to the right and the outside of the right claw 13 hits the obstacle 93 as shown in FIG. Detach upward from the magnet 20 and avoid deformation and breakage of the claw portion 13. Further, as shown in FIG. 9C, when the robot hand moves in the back direction and the rear side surface of the claw portion 13 hits the obstacle 93, the front passive side magnet 21 is driven. The rear side passive magnet 21 is detached from the side magnet 20 in the upward direction, and the rear side passive magnet 21 is detached from the drive side magnet 20 in the downward direction, so that the deformation and breakage of the claw portion 13 can be avoided. Further, the dropped passive-side magnet 21 (drive link 11) is magnetized to the drive-side magnet 20 so that the robot hand can be easily restored.

  In addition, as shown in FIG. 3, the robot hand has a passive magnet 21 and a driving magnet 20 which are arranged coaxially with their end faces facing each other, so that the contact area is wide and the magnetizing force between the magnets can be increased. Can be big. Therefore, it is possible to transmit the necessary rotational force even with a small magnet, and the robot hand can be miniaturized.

  Further, this robot hand is provided with a pair of driving side magnets 20 and passive side magnets 21 for each claw portion 13. In this case, a larger rotational force can be transmitted to one claw portion 13 than to provide one drive-side magnet 20 and one passive-side magnet 21.

  Further, this robot hand is provided with a pair of drive shafts 53 and grips a work with the left and right claw portions 13 facing each other. With this configuration as the minimum unit, a plurality of the minimum units can be connected from the rotating shaft 16 of one motor 17 via a gear or the like. If it does in this way, the number of the nail | claw parts 13 can be increased and the workpiece | work of various shapes, such as a long thing, can be hold | gripped.

<Example 2>
As shown in FIG. 10A, the robot hand of the second embodiment is different from the first embodiment in the form of the robot hand main body 30, the drive link 31, and the driven link 32. Other configurations are the same as those of the first embodiment, and the same configurations are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 10A, the case 33 has a substantially rectangular parallelepiped that is long in the left-right direction, and includes an upper surface 37, a lower surface 38, a front side surface 39, a rear side surface 40, a left side surface 41, a right side surface 42, and a left inclined surface 43. And the right inclined surface 44 (up, down, left and right are up, down, left and right in FIG. 10A, and front and back are the front and back in FIG. 10A, the same applies hereinafter). The case 33 has a first space 51 that is open at the center of the upper surface 37 and into which the rotating shaft 16 of the motor 17 and a drive-side magnet 34 described later are inserted. The case 33 has a pair of second space portions 52 penetrating from the front side surface 39 to the rear side surface 40 and formed on both the left and right sides of the first space portion 51. A passive magnet 35 described later is inserted into the second space 52. In the case 33, a pair of third shaft members 45 extend in the front-rear direction at the center of the lower end portion of the front side surface 39, symmetrically about the center of the first space portion 51, and are inserted through the rear side surface 40. The third shaft member 45 is inserted into a hole of a third joint portion 46 of each of the left and right driven links 32 described later, and pivotally supports the left and right driven links 32.

  The drive side magnet 34 has a cylindrical shape, and the rotating shaft 16 of the motor 17 is inserted into the central shaft hole. The drive-side magnet 34 has an outer peripheral surface magnetized in a spiral shape with an N pole and an S pole (see FIG. 10B). The drive-side magnet 34 is fixed to the rotating shaft 16 of the motor 17 and rotates together. The motor 17 is fixed to the center of the upper surface 37 of the case 33 in a state where the rotating shaft 16 and the drive side magnet 34 are accommodated in the first space 51 of the case 33.

  The case 33 stores one passive magnet 35 in each of the pair of second space portions 52 formed on the left and right sides of the first space portion 51. The passive-side magnet 35 has a cylindrical shape, and its outer peripheral surface is magnetized in a spiral shape with an N pole and an S pole. (See FIG. 10B). The drive-side magnet 34 is arranged such that a part of the side surface is in contact with a part of the side surface of the passive-side magnet 35. That is, in the portion where the passive side magnet 35 and the driving side magnet 34 are close to each other, the passive side magnet 35 and the driving side magnet 34 attract each other. This part corresponds to the transmission part 36 of the robot hand. Each passive magnet 35 has an end face exposed at a front opening formed on the front side 39 of the second space 52 or a rear opening formed on the rear side 40.

  As shown in FIG. 10A, each drive link 31 includes a node portion 70, a first joint portion 72 formed on one end side of the node portion 70, and a first joint formed on the other end side of the node portion 70. 2 joints 73. The first joint portion 72 of each drive link 31 is fixed to the center of both end faces of the passive magnet 35 exposed at the front opening portion or the rear opening portion of the case 33 and rotates together. The second joint portion 73 of each drive link 31 extends below the case 33 toward the front and rear central portion. The 2nd joint part 73 has the hole penetrated in the front-back direction. As described above, two pairs of drive links 31 arranged in front of and behind the case 33 are arranged symmetrically about the rotating shaft 16 of the motor 17.

  Each driven link 32 includes a node portion 71, a third joint portion 46 formed on one end side of the node portion 71, and a fourth joint portion 47 formed on the other end side of the node portion 71. . The 3rd joint part 46 and the 4th joint part 47 have the hole penetrated in the front-back direction. As described above, in the third joint portion 46, the third shaft member 45 arranged symmetrically with the center of the first space portion 51 is inserted in the center portion of the lower surface 38 of the case 33.

  A portion of the claw portion 13 through which the second shaft insertion hole 68 is provided is sandwiched between the second joint portions 73 of the pair of drive links 31 from the front-rear direction. In this state, the second shaft insertion hole 68 of the claw portion 13 communicates with the hole of the second joint portion 73 of the drive link 31, and the second shaft member 76 is connected to the second shaft insertion hole 68 and the second joint portion 73. The hole is inserted through the hole and is rotatably connected. Further, the left claw portion 13 is in contact with the side surface of the fourth joint portion 47 of the driven link 32 at the side surface of the portion through which the first shaft insertion hole 67 is provided. The right claw 13 is in contact with the side surface of the fourth joint portion 47 of the driven link 32 at the side surface of the portion where the first shaft insertion hole 67 is provided. In this state, the first shaft insertion hole 67 of the claw portion 13 communicates with the hole of the fourth joint portion 47 of the driven link 32, and the first shaft member 69 is connected to the first shaft insertion hole 67 and the fourth link of the driven link 32. The joint portion 47 is rotatably connected through the hole of the joint portion 47. In this way, the pair of claw portions 13 are arranged symmetrically about the rotation shaft 16 of the motor 17. The pair of claw portions 13 are positioned so that the opposing surfaces of the left and right claw bodies 63 are substantially parallel. The robot hand forms a link mechanism with the drive link 31, the driven link 32, and the claw portion 13.

  Next, a motion transmission path from the motor 17 to the claw portion 13 will be described. The rotational force of the motor 17 is transmitted to the drive side magnet 34 on which the rotational shaft 16 of the motor 17 is coaxially inserted and fixed. The rotation of the drive-side magnet 34 is transmitted to the passive-side magnets 35 that are orthogonal to the drive-side magnet 34 and sandwich the drive-side magnet 34 via the magnetic forces of the cylindrical surfaces that are magnetized spirally. (Transmission unit 36). The pair of passive magnets 35 rotate symmetrically about the rotation shaft 16 of the motor 17. The drive links 31 fixed to both ends of the pair of passive side magnets 35 rotate symmetrically with the respective passive side magnets 35 around the rotation shaft 16 of the motor 17. At this time, when the second joint portions 73 of the left and right drive links 31 rotate in directions away from each other, the left and right claw portions 13 are separated while being translated from each other by the link mechanism. Further, when the second joint portions 73 of the left and right drive links 31 rotate in a direction approaching each other, the left and right claw portions 13 approach each other while being translated from each other by the link mechanism. Thus, this robot hand can be gripped from either the outer peripheral surface or the inner peripheral surface of the workpiece.

  In this robot hand, even if the workpiece W is displaced, only one of the claw portions 13 is in contact with the workpiece W, and the rotation of the passive magnet 35 is restricted, the drive magnet 34 continues to rotate. Rotational force transmission can be maintained within a predetermined rotation range. For this reason, when the left and right claw portions 13 are not in contact with the workpiece W at the same time, the robot hand maintains the transmission of the rotational force of the motor 17 to the claw portion 13 that has previously contacted the workpiece W. The claw portion 13 that is not in contact with the workpiece W can be brought into contact with the workpiece W.

  Therefore, the robot hand according to the second embodiment can also reliably hold the workpiece W.

The present invention is not limited to the first and second embodiments 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 the first and second embodiments, the current value is controlled by the motor driver, but it may not be the current value.
(2) In the first embodiment, the screw gear is used to transmit the rotational force of the motor to the drive shaft, but the screw gear may not be used.
(3) In the first embodiment, a pair of drive shafts are provided, but may be one or three or more.
(4) In the second embodiment, a pair of passive side magnets are provided, but may be one or three or more.
(5) In the first and second embodiments, there is one motor, but there may be a plurality of motors.
(6) In the first and second embodiments, both ends of the driven link are pivotally supported by the case and the claw portion, but they may be pivotally connected by a magnet or the like without being pivotally supported.
(7) In Examples 1 and 2, the rotation axis of the motor is arranged in the vertical direction, but it may not be arranged in the vertical direction.

11, 31 ... Drive link part (drive link)
13 ... Claw part 14 ... Motor driver 16 ... Rotating shaft 17 ... Motor 18, 19 ... Gear (screw gear, drive screw gear)
20, 34 ... Drive side magnet 21, 35 ... Passive side magnet 22, 36 ... Transmission part 53 ... Drive shaft W, W1, W2, W3 ... Workpiece

Claims (6)

A motor having a rotation axis;
A plurality of claws for gripping the workpiece;
A robot hand provided with a transmission portion provided in a motion transmission path for converting the rotational motion of the motor into a motion in which the claw portion grips a workpiece,
The transmission unit is
A drive-side magnet that is connected to the rotating shaft of the motor and rotates;
A passive side magnet that is disposed in the vicinity of the driving side magnet corresponding to each of the claw portions, and a rotational force of the driving side magnet is transmitted by a magnetic force to rotate,
A robot hand characterized by having   The robot hand according to claim 1, further comprising a motor driver that feedback-controls driving of the plurality of claw portions with a magnitude of a current value flowing through the motor. The transmission unit is
A plurality of shafts arranged perpendicular to the rotation shaft of the motor, connected to the rotation shaft of the motor via a gear, and a drive shaft to which the rotational force of the motor is transmitted;
The drive-side magnet that is fixed coaxially with the drive shaft, rotates with the rotation of the drive shaft, and has a cylindrical outer peripheral shape that is alternately magnetized with N and S poles in the circumferential direction;
The passive-side magnet having a cylindrical outer peripheral shape that is coaxially disposed opposite to the end surface of the drive-side magnet and is alternately magnetized with N and S poles in the circumferential direction;
A drive link portion to which the passive side magnet is fixed and which opens and closes the claw portion;
The robot hand according to claim 1, further comprising:   4. The robot hand according to claim 3, wherein a pair of the drive shafts are provided across the rotation shaft of the motor.   The robot hand according to claim 3 or 4, wherein the drive-side magnet is provided at both ends of the drive shaft. The transmission unit is
A driving-side magnet fixed to the rotating shaft of the motor, rotating together with the rotating shaft, the outer peripheral shape being cylindrical, and the outer peripheral surface being helically magnetized into N and S poles;
A pair of passive side magnets arranged perpendicular to the driving side magnet with the driving side magnet interposed therebetween, and having a cylindrical surface spirally magnetized into N and S poles;
A drive link portion to which the passive side magnet is fixed and which opens and closes the claw portion;
The robot hand according to claim 1, further comprising:

Images