JP7052896B2 - Gripping device - Google Patents

Description

The present invention relates to a gripping device.

When performing assembly work or handling work, a gripping device attached to a robot or the like to grip various parts is used. The gripping device described in Patent Document 1 is provided with a plurality of types of gripping claws inside the housing. The gripping device of Patent Document 1 switches the gripping claws by rotating the gripping claws, and opens and closes the gripping claws by moving in the parallel direction. This grips various parts. Further, the robot hand described in Patent Document 2 performs an opening / closing operation by swinging a claw provided on the frame around a fulcrum pin. This grips the part.

Japanese Unexamined Patent Publication No. 2015-471 Japanese Unexamined Patent Publication No. 2000-28971

In the gripping device, it is required to make the opening / closing operation of the finger portion smoother.

An object of the present invention is to provide a gripping device capable of smoothing the opening / closing operation of a finger portion.

The gripping device according to one aspect of the present invention includes a drive device having a shaft that moves linearly, an attachment having a pair of upper cam holes and being connected to the shaft, and a pair of lower cam holes and the attachment. A base portion overlapping the base portion, a pair of finger portions swingably attached to the base portion, and a cam follower provided on the finger portion are provided, and a part of the cam follower is in contact with the inner wall of the upper cam hole and described above. The other part of the cam follower is in contact with the inner wall of the lower cam hole, and the lower cam hole has a curved shape that is convex in a direction approaching the other lower cam hole, and is orthogonal to the longitudinal direction of the shaft. Assuming that the direction orthogonal to the longitudinal direction of the cam follower is the first direction, the distance between the pair of upper cam holes in the first direction decreases toward the drive device.

As a result, the force of the shaft is not transmitted directly to the cam follower, but is transmitted to the cam follower via the attachment. Since the cam follower is in contact with the inner wall of the upper cam hole, a force is applied to the cam follower in a direction forming an angle with respect to the moving direction of the shaft.
When the shaft moves, the cam follower moves along the moving direction of the shaft and at the same time moves in the first direction along the upper cam hole. As a result, the cam follower moves in the direction along the lower cam hole. Therefore, the cam follower is less likely to receive a reaction force from the inner wall of the lower cam hole as compared with the case where the cam follower is directly connected to the shaft. As a result, it becomes easy to suppress variations in the gripping force of the finger and the moving speed of the finger. Therefore, the gripping device of the present embodiment can smooth the opening / closing operation of the finger portion.

In the gripping device according to one aspect of the present invention, the maximum distance in the first direction between the center lines of the pair of upper cam holes is the maximum distance in the first direction between the center lines of the pair of lower cam holes. Equal to, the minimum distance in the first direction between the centerlines of the pair of upper cam holes is equal to the minimum distance in the first direction between the centerlines of the pair of lower cam holes.

This allows the cam follower to move over the entire length of the lower cam hole. In addition, the size of the attachment may be the same as or smaller than the size of the base. Therefore, the gripping device is miniaturized.

In the gripping device according to one aspect of the present invention, the drive device includes a first shaft and a second shaft that move linearly independently of each other, and the attachment is a first attachment connected to the first shaft. , The second attachment connected to the second shaft,
The first attachment comprises one of a pair of the upper cam holes and the second attachment comprises the other of the pair of the upper cam holes.

As a result, the gripping device can smoothly open and close the pair of fingers and can independently drive the pair of fingers.

According to the present invention, the opening and closing operation of the finger portion can be smoothed.

FIG. 1 is a perspective view of the gripping device according to the first embodiment. FIG. 2 is a front view of the gripping device according to the first embodiment. FIG. 3 is a perspective view of a part of the gripping device according to the first embodiment. FIG. 4 is a front view of a part of the gripping device according to the first embodiment. FIG. 5 is a side view of a part of the gripping device according to the first embodiment. FIG. 6 is a front view for explaining the opening / closing operation of the gripping device according to the first embodiment. FIG. 7 is a front view for explaining the opening / closing operation of the gripping device according to the first embodiment. FIG. 8 is a front view for explaining the opening / closing operation of the gripping device according to the first embodiment. FIG. 9 is a front view for explaining the opening / closing operation of the gripping device according to the first embodiment. FIG. 10 is a control block diagram of the gripping device according to the first embodiment. FIG. 11 is an example of a graph showing the relationship between the current flowing through the drive device and the fingertip force. FIG. 12 is a front view of the gripping device according to the first modification. FIG. 13 is a control block diagram of the gripping device according to the first modification. FIG. 14 is a front view of a part of the gripping device according to the second modification.

An embodiment (embodiment) for carrying out the present invention will be described in detail with reference to the drawings.
The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same.
Furthermore, the components described below can be combined as appropriate.

(First Embodiment)
FIG. 1 is a perspective view of the gripping device according to the first embodiment. FIG. 2 is a front view of the gripping device according to the first embodiment. FIG. 3 is a perspective view of a part of the gripping device according to the first embodiment. FIG. 4 is a front view of a part of the gripping device according to the first embodiment. FIG. 5 is a side view of a part of the gripping device according to the first embodiment.

As shown in FIG. 1, the gripping device 1 of the present embodiment includes a housing 100, a drive device 102, an attachment 5, a base 10, a first finger portion 21, a second finger portion 22, and a first. Cam follower 2
5 and a second cam follower 26 are provided.

The housing 100 is a member that supports the drive device 102 and the base 10. For example, the housing 10
0 is connected to an arm such as a robot hand.

The drive device 102 is a device that drives the first finger portion 21 and the second finger portion 22, and is, for example, a linear actuator. As the linear actuator, an pneumatic linear actuator, an electric linear actuator, an ultrasonic linear actuator, a piezoelectric linear actuator, or the like can be used. The drive device 102 is fixed to the housing 100. The drive device 102 includes a shaft 102a that moves linearly.

As shown in FIG. 1, the attachment 5 is connected to the shaft 102a. The attachment 5 moves linearly with the shaft 102a. Attachment 5 is the first plate 5
01 and a second plate 502 are provided. The first plate 501 is perpendicular to the longitudinal direction of the shaft 102a. The second plate 502 is perpendicular to the first plate 501. The second plate 502 extends from the first plate 501 on the opposite side of the drive device 102. The second plate 502 has a first upper cam hole 51 and a second upper cam hole 52.
And prepare.

In the following description, the first direction Dx, the second direction Dy and the third direction Dz are used. The direction along the longitudinal direction of the shaft 102a is defined as the second direction Dy. The direction perpendicular to the second plate 502 is defined as the third direction Dz. The direction perpendicular to both the second direction Dy and the third direction Dz is defined as the first direction Dx. Not limited to this, the second direction Dy may intersect the first direction Dx at an angle other than 90 °. The third direction Dz may intersect the first direction Dx and the second direction Dy at an angle other than 90 °. In addition, "front view" means the third direction Dz.
Refers to the case seen from.

As shown in FIG. 2, the distance in the first direction Dx between the first upper cam hole 51 and the second upper cam hole 52 decreases toward a certain direction of the drive device 102.
The first upper cam hole 51 includes a vertical hole 51a and a horizontal hole 51b. The longitudinal direction of the vertical hole 51a forms an angle with respect to the second direction Dy. The vertical hole 51a approaches the second upper cam hole 52 toward a certain direction of the drive device 102. The horizontal hole 51b intersects the vertical hole 51a. For example, the lateral hole 51b is along the first direction Dx. Therefore, the first upper cam hole 51 is substantially L-shaped when viewed from the front.

The second upper cam hole 52 includes a vertical hole 52a and a horizontal hole 52b. The longitudinal direction of the vertical hole 52a forms an angle with respect to the second direction Dy. The vertical hole 52a approaches the first upper cam hole 51 toward a certain direction of the drive device 102. The horizontal hole 52b intersects the vertical hole 52a. For example, the lateral hole 52b is along the first direction Dx. Therefore, the second upper cam hole 52 is substantially L-shaped when viewed from the front. In front view, the second upper cam hole 52 is symmetrical with the first upper cam hole 51 with a straight line parallel to the second direction Dy as the axis of symmetry.

As shown in FIGS. 3 and 5, the base 10 is a plate-shaped member having a first surface 10c and a second surface 10d opposite to the first surface 10c. The base 10 is a side 1 facing each other in a front view.
It is a rectangular shape having 0a and a side 10b. The side 10a of the base 10 is connected to the housing 100. For example, the base 10 is integrally formed with the housing 100. The base 10 is not limited to this, and may have a polygonal shape, a circular shape, an elliptical shape, or the like. In addition, in FIGS. 3 to 5, the illustration of the housing 100 connected to the side 10a is omitted.

The first finger portion 21 and the second finger portion 22 are provided on the base portion 10 so as to be swingable. As shown in FIG. 4, the first finger portion 21 and the second finger portion 22 are provided adjacent to each other with an interval in the first direction Dx. The first finger portion 21 and the second finger portion 22 are each elongated and arranged so as to have a longitudinal direction in a direction intersecting the side 10b of the base portion 10. The first finger portion 21 and the second finger portion 22 have a portion that overlaps with the base portion 10 and a portion that is arranged outside the side 10b of the outer periphery of the base portion 10 in front view.

The first finger portion 21 is provided with a long hole 33 on one end side in the longitudinal direction and a fixing portion 21a on the other end side. Similarly, the second finger portion 22 is provided with an elongated hole 34 on one end side in the longitudinal direction, and the fixing portion 22a is provided on the other end side.
To prepare for. The elongated hole 33 has a longitudinal direction along the longitudinal direction of the first finger portion 21, and has a first inner wall 33a and a second inner wall 33b. The first inner wall 33a and the second inner wall 33b face each other in the longitudinal direction of the first finger portion 21. The first inner wall 33a is located on one end side of the first finger portion 21, and the second inner wall 33b is located.
Is located on the central side of the first finger portion 21.

Similarly, the elongated hole 34 has a longitudinal direction along the longitudinal direction of the second finger portion 22, and has a first inner wall 34a and a second inner wall 34b. The first inner wall 34a and the second inner wall 34b face each other in the longitudinal direction of the second finger portion 22. The first inner wall 34a is located on one end side of the second finger portion 22, and the second inner wall 34b is located on the central portion side of the second finger portion 22.

As shown in FIGS. 3 and 4, the base portion 10 is provided with a support portion 11 and a support portion 12.
The support portion 11 and the support portion 12 are columnar and penetrate the elongated hole 33 and the elongated hole 34 in the third direction Dz, respectively. As shown in FIG. 5, the support portion 12 includes an overhanging portion 12a and a shaft portion 12b. The shaft portion 12b projects from the first surface 10c of the base portion 10 in the third direction Dz and penetrates the elongated hole 34. The overhanging portion 12a is provided at the end of the shaft portion 12b and has a diameter larger than the width (length in the lateral direction) of the elongated hole 34. The second finger portion 22 is arranged between the overhanging portion 12a and the base portion 10. With such a configuration, the second finger portion 22 is swingable with respect to the base portion 10 and is movable in the longitudinal direction. Although the first finger portion 21 and the support portion 11 are not shown in FIG. 5, the support portion 11 has the same configuration and penetrates the elongated hole 33. The first finger portion 21 is swingable with respect to the base portion 10 and is movable in the longitudinal direction.

The fixed portion 21a and the fixed portion 22a have a width smaller than the width of the first finger portion 21 and the second finger portion 22, respectively. As shown in FIG. 5, the fixing portion 22a is provided with a through hole 24. Various members are attached to the fixing portion 22a via the through hole 24 by using a screw member such as a bolt. The through hole 24 may be a screw hole. Further, although omitted in FIG. 5, a through hole is also provided in the fixing portion 21a, and various members are attached to the fixing portion 21a.

A fingertip portion suitable for a target component or the like to be gripped by the gripping device 1 can be attached to the fixing portion 21a and the fixing portion 22a. As shown in FIG. 1, the fixed portion 22a and the fixed portion 21a have
For example, a claw portion 41 and a claw portion 42 are provided, respectively. The gripping device 1 has a first finger portion 21 and a second finger portion 21.
By closing the finger portion 22, the component can be gripped between the claw portion 41 and the claw portion 42.

The claw portion 41 has a mounting portion 41a and a grip portion 41b. The claw portion 42 is a mounting portion 42a.
And a grip portion 42b. The mounting portion 41a and the mounting portion 42a are fixed portions 21, respectively.
It is attached to a and 22a. The grip portion 41b and the grip portion 42b are portions that sandwich and grip the grip target. The grip portion 41b and the grip portion 42b form an angle with respect to the mounting portion 41a and the mounting portion 42a. The grip portion 41b is formed with a recess 41c, a recess 41d, a recess 41e and a recess 41f. The grip portion 42b is formed with a recess 42c, a recess 42d, a recess 42e and a recess 42f. By providing such a claw portion 41 and a claw portion 42,
It is possible to grip various gripping objects.

As shown in FIG. 4, the base 10 includes a first lower cam hole 31 and a second lower cam hole 32. As shown in FIG. 5, the second lower cam hole 32 has a first surface 10c to a second surface 10d of the base 10.
It is a through hole that penetrates through. The first lower cam hole 31, which is not shown in FIG. 5, is also a through hole. The first lower cam hole 31 and the second lower cam hole 32 are not limited to this, and the first surface 1 is used.
It may be a groove formed in a concave shape from 0c toward the second surface 10d.

As shown in FIG. 4, the first lower cam hole 31 and the second lower cam hole 32 have a curved shape that is convex in the direction of approaching each other. That is, the first lower cam hole 31 has a curved shape that is convex in the direction approaching the second lower cam hole 32. In front view, the first lower cam hole 31 draws an arc centered on a point located on the opposite side of the second lower cam hole 32. The second lower cam hole 32 is the first
It has a curved shape that is convex in the direction approaching the lower cam hole 31. 2nd lower cam hole 3 in front view
Reference numeral 2 is an arc centered on a point located on the opposite side of the first lower cam hole 31. Specifically, the first direction D of one end 31a of the first lower cam hole 31 and one end 32a of the second lower cam hole 32.
The distance at x is larger than the distance between the intermediate portion of the first lower cam hole 31 and the intermediate portion of the second lower cam hole 32. The distance between the other end 31b of the first lower cam hole 31 and the other end 32b of the second lower cam hole 32 in the first direction Dx is the distance between the intermediate portion of the first lower cam hole 31 and the intermediate portion of the second lower cam hole 32. Greater than the distance.

The maximum distance D1 in the first direction Dx between the center line C51 of the first upper cam hole 51 shown in FIG. 2 and the center line C52 of the second upper cam hole 52 is the center of the first lower cam hole 31 shown in FIG. It is equal to the maximum distance D3 in the first direction Dx between the line C31 and the center line C32 of the second lower cam hole 32. The minimum distance D2 in the first direction Dx between the center line C51 of the first upper cam hole 51 shown in FIG. 2 and the center line C52 of the second upper cam hole 52 is the center of the first lower cam hole 31 shown in FIG. First direction Dx between line C31 and center line C32 of second lower cam hole 32
Is equal to the minimum distance D4 in. The center line C51 is a line segment equidistant from each of the facing inner walls in a portion of the first upper cam hole 51 having a constant width. Center line C
Reference numeral 52 is a line segment equidistant from each of the facing inner walls in the portion of the second upper cam hole 52 having a constant width. The center line C31 is a line segment equidistant from each of the facing inner walls in a portion of the first lower cam hole 31 having a constant width. Center line C
Reference numeral 32 is a line segment equidistant from each of the facing inner walls in the portion of the second lower cam hole 32 having a constant width.

The support portion 11 is arranged adjacent to the other end 31b of the first lower cam hole 31. Further, the support portion 11 overlaps with one end 31a of the first lower cam hole 31 when viewed from the second direction Dy. Support part 12
Is arranged adjacent to the other end 32b of the second lower cam hole 32. Further, the support portion 12 overlaps with one end 32a of the second lower cam hole 32 from the second direction Dy.

The first cam follower 25 is provided on the first finger portion 21. For example, the first cam follower 25 is located at the end of the first finger portion 21 opposite to the fixed portion 21a. 1st Cam Follower 2
A part of 5 is in contact with the inner wall of the first upper cam hole 51. A part of the first cam follower 25 is in contact with the inner wall of the first lower cam hole 31. That is, the first cam follower 25 is the first.
It is provided from the upper cam hole 51 to the first lower cam hole 31. The first cam follower 25 is movable along the first upper cam hole 51 and is movable along the first lower cam hole 31. It can also be said that the first direction Dx is a direction orthogonal to the longitudinal direction of the shaft 102a and orthogonal to the longitudinal direction of the first cam follower 25.

The second cam follower 26 is provided on the second finger portion 22. For example, the second cam follower 26 is located at the end of the second finger portion 22 opposite to the fixed portion 22a. 2nd Cam Follower 2
A part of 6 is in contact with the inner wall of the second upper cam hole 52. A part of the second cam follower 26 is in contact with the inner wall of the second lower cam hole 32. That is, the second cam follower 26 is the second.
It is provided from the upper cam hole 52 to the second lower cam hole 32. The second cam follower 26 is movable along the second upper cam hole 52 and is movable along the second lower cam hole 32.

The first cam follower 25 and the second cam follower 26 may have any configuration as long as they can move along the first lower cam hole 31 and the second lower cam hole 32, respectively. As shown in FIG. 5, for example, the second cam follower 26 has a shaft portion 26b, an overhanging portion 26c, and an overhanging portion 26.
It has a and a shaft portion 26d. The shaft portion 26b is fixed to the second finger portion 22. The shaft portion 26b penetrates the second lower cam hole 32. The overhanging portion 26c has a diameter larger than the width of the second lower cam hole 32, and is arranged on the second surface 10d side of the base portion 10. The overhanging portion 26a has a diameter larger than the width of the second upper cam hole 52, and is arranged at an end portion opposite to the overhanging portion 26c. The shaft portion 26d extends from the overhanging portion 26a toward the second upper cam hole 52. At least a part of the shaft portion 26d is located inside the second upper cam hole 52. With such a configuration, the second
The cam follower 26 is movable along the second lower cam hole 32. The second cam follower 26 may be provided with, for example, a rolling bearing at a portion in contact with the inner wall of the second upper cam hole 52 or a portion in contact with the inner wall of the second lower cam hole 32. The first cam follower 25, which is not shown in FIG. 5, has the same configuration.

The gripping device 1 of the present embodiment has a first upper cam hole 51, a second upper cam hole 52, and a first.
Lower cam hole 31, second lower cam hole 32, first cam follower 25 and second cam follower 26
It has a cam mechanism composed of. When the first cam follower 25 moves along the first lower cam hole 31, the opening / closing operation of the first finger portion 21 is performed. When the second cam follower 26 moves along the second lower cam hole 32, the opening / closing operation of the second finger portion 22 is performed.

By the way, if the first cam follower 25 and the second cam follower 26 are directly connected to the shaft 102a, a force in the moving direction (second direction Dy) of the shaft 102a is applied to the first cam follower 25 and the second cam follower 26. become. In this case, since the first lower cam hole 31 and the second lower cam hole 32 are curved, the forces received by the first cam follower 25 and the second cam follower 26 from the first lower cam hole 31 and the second lower cam hole 32 are likely to fluctuate. Therefore, there is a limit in suppressing variations in the gripping force of the first finger portion 21 and the second finger portion 22 and the moving speeds of the first finger portion 21 and the second finger portion 22. Therefore, it is difficult to make the opening / closing operation of the first finger portion 21 and the second finger portion 22 smoother.

The opening / closing operation of the gripping device 1 of the present embodiment will be described with reference to FIGS. 2 and 6 to 9. 6 to 9 are front views for explaining the opening / closing operation of the gripping device 1 according to the first embodiment. FIG. 2 shows a state in which the first finger portion 21 and the second finger portion 22 are closed. Specifically, the closed state is a state in which the distance L2 between the end portion 21e of the first finger portion 21 and the end portion 22e of the second finger portion 22 in the first direction Dx is the smallest. In the present embodiment, the end portion 21e of the first finger portion 21 is the tip of the fixing portion 21a and overlaps with the virtual line B1 when viewed from the third direction Dz. The virtual line B1 is a straight line passing through the center of the first cam follower 25 and the center of the support portion 11 in front view. The end portion 22e of the second finger portion 22 is the tip of the fixing portion 22a and is in the third direction D.
The part overlapping the virtual line B2 when viewed from z is shown. The virtual line B2 is the second cam follower 2 when viewed from the front.
It is a straight line passing through the center of 6 and the center of the support portion 12.

As shown in FIG. 2, in the closed state, the first cam follower 25 is located at the end of the vertical hole 51a. At this time, the first cam follower 25 is located at one end 31a (see FIG. 4) of the first lower cam hole 31. As a result, the first finger portion 21 is directed in the direction parallel to the reference line A1. Reference line A
Reference numeral 1 is a straight line passing through the end portion of the center line C51 on the vertical hole 51a side and the center of the support portion 11 in front view. At this time, the support portion 11 is located on the second inner wall 33b side of the elongated hole 33. That is, the portion of the first finger portion 21 provided with the elongated hole 33 overlaps with the base portion 10. The portion of the first finger portion 21 where the elongated hole 33 is not provided is located outside the side 10b of the base portion 10.

Similarly, the second cam follower 26 is located at the end of the vertical hole 52a. At this time, the second cam follower 26 is located at one end 32a (see FIG. 4) of the second lower cam hole 32. As a result, the second
The finger portion 22 is directed in a direction parallel to the reference line A2. The reference line A2 is the center line C52 when viewed from the front.
It is a straight line passing through the end portion on the vertical hole 52a side and the center of the support portion 12. At this time, the support portion 12 is located on the second inner wall 34b side of the elongated hole 34. That is, the portion of the second finger portion 22 provided with the elongated hole 34 overlaps with the base portion 10. The portion of the second finger portion 22 where the elongated hole 34 is not provided is located outside the side 10b of the base portion 10.

Here, the distance in the second direction Dy between one side 10a of the base portion 10 and the end portion 21e of the first finger portion 21 and the end portion 22e of the second finger portion 22 is defined as the distance L1. Further, in the example shown in FIG. 2, the reference line A1 and the reference line A2 are parallel to each other in the closed state. That is, the first finger portion 21
And the second finger portion 22 are in a parallel state, but the present invention is not limited to this. In the closed state, the first finger portion 21 and the second finger portion 22 may be arranged so as to form a predetermined angle.

6 to 8 show an intermediate state between the closed and open states. As shown in FIGS. 6 and 7, when the shaft 102a moves, the first cam follower 25 moves toward the lateral hole 51b, and the second cam follower 26 moves toward the lateral hole 52b. As a result, a force is applied to the first cam follower 25 in the direction along the first lower cam hole 31. 2nd Cam Follower 26
Is applied with a force in the direction along the second lower cam hole 32. Therefore, the first cam follower 25 and the second cam follower 26 have the first lower cam hole 31 and the second lower cam hole 32 as compared with the case where the force of the second direction Dy is directly applied to the first cam follower 25 and the second cam follower 26. It is hard to receive the reaction force from the inner wall of. Therefore, in the gripping device 1, the first cam follower 25 and the second cam follower 26 move smoothly.

By such an operation, the first finger portion 21 is directed in the direction parallel to the virtual line B1. Here, the angle formed by the virtual line B1 and the reference line A1 is defined as the opening / closing angle θ1 of the first finger portion 21. The second finger portion 22 is also directed in the direction parallel to the virtual line B2. Here, the angle formed by the virtual line B2 and the reference line A2 is defined as the opening / closing angle θ2 of the second finger portion 22. The end 21e of the first finger 21 and the second finger 2
The distance L2 in the first direction Dx between the end portion 22e of 2 is larger than that in the closed state of FIG.

When the shaft 102a further moves from the state shown in FIG. 7, the state shown in FIG. 8 is obtained. In FIG. 8, the first cam follower 25 is located at the end of the lateral hole 51b. At this time, the first cam follower 25 is located in the portion of the first lower cam hole 31 closest to the second lower cam hole 32. The second cam follower 26 is located at the end of the lateral hole 52b. At this time, the second cam follower 26 is located in the portion of the second lower cam hole 32 closest to the first lower cam hole 31. FIG. 8 shows a state in which the first cam follower 25 is closest to the second cam follower 26.

When the shaft 102a further moves from the state shown in FIG. 8, the state shown in FIG. 9 is obtained. In FIG. 9, the first cam follower 25 is located in the middle of the lateral hole 51b. At this time, the first cam follower 25 is located at the other end 31b of the first lower cam hole 31. The second cam follower 26 has a lateral hole 5
It is located in the middle of 2b. At this time, the second cam follower 26 is the other end 32 of the second lower cam hole 32.
Located at b. FIG. 9 shows a state in which the first finger portion 21 and the second finger portion 22 are open.

In the intermediate state and the open state, the first finger portion 21 is compared with the closed state shown in FIG.
The length of the portion of the second finger portion 22 that protrudes outside the side 10b of the base portion 10 becomes longer. The base 10 of the first finger portion 21 and the second finger portion 22 according to the opening / closing angle θ1 and the opening / closing angle θ2.
The length of the portion located outside the side 10b is changed. The distance L1 in the intermediate state and the open state coincides with the distance L1 in the closed state in FIG. As a result, the opening / closing angle θ1 and the opening / closing angle θ2 change while the distance L1 is kept constant.

As described above, the gripping device 1 of the present embodiment has a first upper cam hole 51, a second upper cam hole 52, a first lower cam hole 31, a second lower cam hole 32, a first cam follower 25, and a second cam follower 26. It has a cam mechanism composed of. By the operation of the cam mechanism, the first cam follower 25 and the second cam follower 26 move, so that the opening / closing angles θ1 and θ2 of the first finger portion 21 and the second finger portion 22 change. The first finger portion 21 and the second finger portion 22 are opened so that the distance L2 is larger than the width of the base portion 10 (the length of the side 10b in the first direction Dx). Therefore, it is possible to suppress the increase in the width of the base 10 to reduce the size of the gripping device 1 and to grip various parts having different outer diameter shapes.

Further, due to the operation of the cam mechanism, the opening / closing angle θ1 of the pair of first finger portions 21 and the second finger portions 22 is set.
Depending on θ2, the lengths of the portions of the first finger portion 21 and the second finger portion 22 outside the outer circumference of the base portion 10 are changed. That is, the cam mechanism also functions as a length adjusting mechanism. As a result, the opening and closing operations of the first finger portion 21 and the second finger portion 22 can be performed while maintaining a constant distance L1. Therefore, the gripping device 1 can grip various parts having different shapes. Further, in the present embodiment, ATC (Au) for exchanging the claws attached to the fixing portion 21a and the fixing portion 22a.
It is also possible to configure without providing to Tool changer). Further, it is not necessary to adjust the height according to the degree of opening / closing on the arm side of the robot connected to the gripping device 1. Therefore, the gripping device 1 can simplify the control program of the robot and the operation of the robot, and can shorten the lead time.

FIG. 10 is a control block diagram of the gripping device according to the first embodiment. FIG. 11 is an example of a graph showing the relationship between the current flowing through the drive device and the fingertip force. The control device 101 is a personal computer (PC) or a computer such as a server system. Control device 101
Includes a storage unit 101A and a calculation unit 101B. The storage unit 101A is a hard disk, RA
Includes M (Random Access Memory), ROM (Read Only Memory), etc. Arithmetic unit 101
B includes a CPU (Central Processing Unit) and the like.

The input unit 110 is an information input device such as a keyboard or a touch panel. Information or an operation program related to the operation of the gripping device 1 is input from the input unit 110 to the storage unit 101A.

The drive device 102 operates by a control signal from the control device 101. The above-mentioned opening / closing operation of the first finger portion 21 and the second finger portion 22 is performed by the driving force input from the driving device 102. Specifically, the driving force generated by the driving device 102 is the shaft 102a and the attachment 5.
, It is transmitted to the first cam follower 25 and the second cam follower 26. By moving the first cam follower 25 and the second cam follower 26, the opening and closing operations of the first finger portion 21 and the second finger portion 22 are performed.

The sensor unit 103 includes, for example, a displacement sensor, an angle sensor, a speed sensor, a pressure sensor, and the like. The sensor unit 103 detects the operating state of the first finger unit 21 and the second finger unit 22, and outputs various information to the control device 101. The control device 101 drives the drive device 102 according to the operating states of the first finger portion 21 and the second finger portion 22.

For example, the control device 101 may drive the drive device 102 based on the displacement of the first finger portion 21 and the second finger portion 22. For example, the control device 101 may drive the drive device 102 based on the opening / closing angles of the first finger portion 21 and the second finger portion 22. For example, the control device 101 is the first
The drive device 102 may be driven based on the speed of the finger portion 21 and the second finger portion 22. for example,
The control device 101 may drive the drive device 102 based on the fingertip force. The fingertip force is a force applied to the gripping object sandwiched between the first finger portion 21 and the second finger portion 22.
That is, it can be said that the fingertip force is a reaction force received by the first finger portion 21 and the second finger portion 22 from the gripping target. Further, the control device 101 may drive the drive device 102 based on information in which the displacement, opening / closing angle, speed, fingertip force, etc. of the first finger portion 21 and the second finger portion 22 are combined.

The control device 101 stores in the storage unit 101A the relationship between the current flowing through the drive device 102 and the fingertip force as shown in FIG. As a result, the control device 101 can calculate the fingertip force based on the current flowing through the drive device 102. The configuration shown in FIG. 10 is merely an example and can be changed as appropriate.

As described above, the gripping device 1 includes a drive device 102, an attachment 5, a base 10, a pair of fingers (first finger portion 21 and a second finger portion 22), and a cam follower (first cam follower). 25 and a second cam follower 26). The drive device 102 has a shaft 102a that moves linearly. The attachment 5 has a pair of upper cam holes (first upper cam hole 51 and second upper cam hole 52) and is connected to the shaft 102a. The base 10 comprises a pair of lower cam holes (first lower cam hole 31 and second lower cam hole 32) and overlaps the attachment 5. The pair of fingers is swingably attached to the base 10. The first cam follower 25 is provided on the first finger portion 21. The second cam follower 26 is the second finger portion 22.
It is provided in. A part of the first cam follower 25 is in contact with the inner wall of the first upper cam hole 51. The other part of the first cam follower 25 is in contact with the inner wall of the first lower cam hole 31. A part of the second cam follower 26 is in contact with the inner wall of the second upper cam hole 52. The other part of the second cam follower 26 is in contact with the inner wall of the second lower cam hole 32. The first lower cam hole 31 has a curved shape that is convex in the direction approaching the second lower cam hole 32. The second lower cam hole 32 has a curved shape that is convex in the direction approaching the first lower cam hole 31. Assuming that the direction orthogonal to the longitudinal direction of the shaft 102a and orthogonal to the longitudinal direction of the cam follower is the first direction Dx, the distance in the first direction Dx between the pair of upper cam holes is determined by the drive device 102. It gets smaller as you go.

As a result, the force of the shaft 102a is reduced to the cam followers (first cam followers 25 and second cam followers 25).
It is not transmitted directly to the cam follower 26), but is transmitted to the cam follower via the attachment 5. Since the cam follower is in contact with the inner wall of the upper cam hole (first upper cam hole 51 and second upper cam hole 52), a force in a direction forming an angle with respect to the moving direction of the shaft 102a is applied to the cam follower. When the shaft 102a moves, the cam follower
At the same time as moving along the moving direction of the shaft 102a, it also moves in the first direction Dx along the upper cam hole. As a result, the cam follower moves in the direction along the lower cam hole (first lower cam hole 31 and second lower cam hole 32). Therefore, the cam follower is the shaft 10.
The cam follower is less likely to receive a reaction force from the inner wall of the lower cam hole as compared with the case where it is directly connected to 2a. As a result, it becomes easy to suppress variations in the gripping force and the moving speed of the fingers by the fingers (first finger 21 and second finger 22). Therefore, the gripping device 1 of the present embodiment is
The opening and closing operation of the finger can be smoothed.

Further, in the gripping device 1, the first direction D between the center lines (between the center line C51 and the center line C52) of the pair of upper cam holes (first upper cam hole 51 and second upper cam hole 52).
The maximum distance D1 in x is the maximum distance D3 in the first direction Dx between the center lines (between the center line C31 and the center line C32) of the pair of lower cam holes (first lower cam hole 31 and second lower cam hole 32). be equivalent to. Minimum distance D2 in the first direction Dx between the centerlines of a pair of upper cam holes
Is equal to the minimum distance D4 in the first direction Dx between the centerlines of the pair of lower cam holes.

As a result, the cam followers (first cam follower 25 and second cam follower 26) can move over the entire length of the lower cam holes (first lower cam hole 31 and second lower cam hole 32). Further, the size of the attachment 5 may be the same as or smaller than the size of the base 10. Therefore, the gripping device 1 is miniaturized.

(First modification)
FIG. 12 is a front view of the gripping device according to the first modification. FIG. 13 is a control block diagram of the gripping device according to the first modification. In the following description of the modification, the same components as those described in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 12, the gripping device 1A of the first modification includes a driving device 102A and an attachment 5A. The drive device 102A includes the first drive device 1021 and the second drive device 1.
022 and. The attachment 5A includes a first attachment 55 and a second attachment 56.

The first drive device 1021 is a device that drives the first finger portion 21, and is, for example, a linear actuator. The first drive device 1021 is fixed to the housing 100. 1st drive device 1
021 includes a first shaft 1021a that moves linearly.

The second drive device 1022 is a device that drives the second finger portion 22, and is, for example, a linear actuator. The second drive device 1022 is fixed to the housing 100. 2nd drive device 1
022 includes a second shaft 1022a that moves linearly.

As shown in FIG. 12, the first attachment 55 is connected to the first shaft 1021a. The first attachment 55 moves linearly together with the first shaft 1021a. The first attachment 55 includes a first plate 5015 and a second plate 5025. 1st
The plate 5015 is perpendicular to the longitudinal direction of the first attachment 55. The second plate 5025 is perpendicular to the first plate 5015. The second plate 5025 is
It extends from the first plate 5015 to the opposite side of the first drive device 1021. The second plate 5025 includes a first upper cam hole 51.

As shown in FIG. 12, the second attachment 56 is connected to the second shaft 1022a. The second attachment 56 moves linearly with the second shaft 1022a. The second attachment 56 includes a first plate 5016 and a second plate 5026. 1st
The plate 5016 is perpendicular to the longitudinal direction of the second attachment 56. The second plate 5026 is perpendicular to the first plate 5016. The second plate 5026 is
It extends from the first plate 5016 to the opposite side of the second drive device 1022. The second plate 5026 includes a second upper cam hole 52.

The first drive device 1021 and the second drive device 1022 operate by the control signal from the control device 101. The driving force input from the first driving device 1021 causes the first finger portion 21 to be opened and closed. Specifically, the driving force generated by the first driving device 1021 is the first shaft 10.
It is transmitted to 21a, the first attachment 55, and the first cam follower 25. 1st Cam Follower 2
By the movement of 5, the opening and closing operation of the first finger portion 21 is performed. Further, the opening / closing operation of the second finger portion 22 is performed by the driving force input from the second driving device 1022. Specifically, the driving force generated by the second driving device 1022 is transmitted to the second shaft 1022a, the second attachment 56, and the second cam follower 26. By moving the second cam follower 26, the opening / closing operation of the second finger portion 22 is performed.

The first sensor unit 1031 and the second sensor unit 1032 include, for example, a displacement sensor, an angle sensor, a speed sensor, a pressure sensor, and the like. The first sensor unit 1031 detects the operating state of the first finger unit 21 and outputs various information to the control device 101. The second sensor unit 1032 is the second finger unit 2.
The operating state of 2 is detected, and various information is output to the control device 101. The control device 101 is the first
The first drive device 1021 is driven according to the operating state of the finger portion 21. The control device 101 is the second
The second drive device 1022 is driven according to the operating state of the finger portion 22.

For example, the control device 101 may drive the first drive device 1021 and the second drive device 1022 based on the respective displacements of the first finger portion 21 and the second finger portion 22. For example, the control device 101 may drive the first drive device 1021 and the second drive device 1022 based on the opening / closing angles of the first finger portion 21 and the second finger portion 22, respectively. For example, the control device 101 is the first
The first drive device 1021 and the second drive device 1022 may be driven based on the respective speeds of the finger portion 21 and the second finger portion 22. For example, the control device 101 may drive the first drive device 1021 and the second drive device 1022 based on the fingertip force. Further, the control device 101 is
The first drive device 1021 and the second drive device 1022 may be driven based on the information in which the displacement, opening / closing angle, speed, fingertip force, etc. of the first finger portion 21 and the second finger portion 22 are combined.

As described above, in the gripping device 1A of the first modification, the drive device 102A includes a first shaft 1021a and a second shaft 1022a that linearly move independently of each other. The attachment 5A is a first attachment 55 connected to the first shaft 1021a.
And a second attachment 56 connected to the second shaft 1022a. The first attachment 55 includes one of a pair of upper cam holes (first upper cam hole 51). The second attachment 56 includes the other of the pair of upper cam holes (second upper cam hole 52).

As a result, the gripping device 1A can smoothly open and close the pair of fingers (first finger portion 21 and second finger portion 22), and in addition, drives the pair of fingers independently. be able to.

(Second modification)
FIG. 14 is a front view of a part of the gripping device according to the second modification. Gripping device 1 shown in FIG.
In B, the claw portion 43 and the claw portion 44 are attached to the first finger portion 21 and the second finger portion 22, respectively. The claw portion 43 and the claw portion 44 are each having a square columnar shape, and the groove 43a and the groove portion 44a are provided on the surfaces facing each other. In this modification, the component can be sandwiched and gripped between the groove 43a and the groove 44a.

The configurations of the gripping device 1, the gripping device 1A, and the gripping device 1B described above may be appropriately changed. For example, the shapes, opening / closing angles, lengths, and the like of the first finger portion 21 and the second finger portion 22 are merely examples and can be changed as appropriate. Further, the shapes of the first upper cam hole 51, the second upper cam hole 52, the first lower cam hole 31, and the second lower cam hole 32 can be appropriately changed.
By doing so, the opening / closing angles θ1 and θ2 of the first finger portion 21 and the second finger portion 22 can be changed.

Further, the shape of the claw portion attached to the first finger portion 21 and the second finger portion 22 is not limited to the above-mentioned shape. For example, the claw portion may be L-shaped. For example, the claw portion may have a shape in which a cylinder and a hemisphere are combined. Further, the material of the claw portion is not particularly limited. The material of the claw portion is, for example, metal, synthetic resin, synthetic rubber, or the like. Examples of the synthetic resin include ABS resin, polyacetal and the like. Examples of the synthetic rubber include nitrile rubber (NBR) and silicone rubber. Further, the base material of the claw portion may be formed of metal, and the portion of the claw portion in contact with the gripping object may be formed of synthetic resin or synthetic rubber.

1, 1A, 1B gripping device 10 base 10a, 10b side 10c first surface 10d second surface 100 housing 102, 102A drive device 102a shaft 1021 first drive device 1021a first shaft 1022 second drive device 1022a second shaft 11 , 12 Support part 21 1st finger part 22 2nd finger part 21a, 22a Fixed part 21e, 22e End part 24 Through hole 25 1st cam follower 26 2nd cam follower 26a, 26c Overhanging part 26b, 26d Shaft part 31 1st lower cam Hole 32 Second lower cam hole 33, 34 Long hole 41, 42, 43, 44 Claw part 5, 5A Attachments 501, 5015, 5016 First plate 502, 5025, 5026 Second plate 51 First upper cam hole 51a Vertical hole 51b Horizontal hole 52 Second upper cam hole 52a Vertical hole 52b Horizontal hole 55 First attachment 56 Second attachment

Claims (8)

A drive with a shaft that moves linearly in the longitudinal direction,
An attachment that has a pair of upper cam holes and is connected to the shaft.
A pair of supports provided apart from the drive device in the longitudinal direction of the shaft from the attachment.
It has a cam follower in contact with the inner wall of the upper cam hole and a pair of fingers having an elongated hole penetrating the support.
The upper cam hole includes a vertical hole and a horizontal hole that intersects the vertical hole.
When the shaft moves away from the drive device, the vertical hole brings the cam follower and the support portion closer to each other in the longitudinal direction of the shaft.
The lateral hole is a gripping device that brings the cam follower closer to the other upper cam hole when the shaft moves away from the drive device. The longitudinal direction of the vertical hole approaches the other upper cam hole toward a certain direction of the drive device.
The longitudinal direction of the lateral hole intersects the longitudinal hole at the end of the longitudinal hole on the drive device side, and as the drive device is directed toward a certain direction, the longitudinal direction of the shaft is longer than that of the longitudinal hole. The gripping device according to claim 1, wherein the gripping device approaches the other upper cam hole at a large angle. The gripping device according to claim 1 or 2, wherein when the shaft moves linearly, the angle in the longitudinal direction of the finger portion with respect to the direction in which the center line of the upper cam hole extends changes. The finger portion is swingably provided on the base portion, and the length of the portion of the finger portion outside the outer circumference of the base portion is changed according to the angle with respect to the center line of the upper cam hole. The gripping device according to any one of Items 1 to 3. The finger portion is provided with a fixing portion at an end opposite to the cam follower sandwiching the elongated hole.
The gripping device according to any one of claims 1 to 4, wherein the fixing portion is attached so that the claw portion can be reattached. The drive device includes a first shaft and a second shaft that move linearly independently of each other.
The attachment includes a first attachment connected to the first shaft and a second attachment connected to the second shaft.
The first attachment comprises one of a pair of the upper cam holes.
The gripping device according to any one of claims 1 to 5, wherein the second attachment includes the other of a pair of the upper cam holes. The sensor unit that detects the operating state of the finger unit and
The gripping device according to any one of claims 1 to 6, further comprising a control device for driving the driving device according to the operating state input from the sensor unit. The gripping device according to claim 7, wherein the sensor unit includes at least one of a displacement sensor, an angle sensor, a speed sensor, and a pressure sensor.

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