JP2009291871A - Gripping hand for robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gripping hand for a robot can stably grip articles of various shapes and dimensions. <P>SOLUTION: This gripping hand for a robot includes a base having an opening for accepting an article, three rotating shafts which extend along the center axis, disposed on a pitch circle concentric to the center axis at equal angular intervals, and rotatingly driven, and gripping fingers attached to the rotating shafts and movable to the released position or the gripping position where the article is gripped therebetween. The rotating shaft and a drive device are disposed at positions where the rotating shaft and the drive device are not interfered with the article accepted into the opening. Consequently, the articles of various shapes and dimensions can be stably gripped. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a robot gripping hand for use with a robot to grip an article.

  As a conventional robot gripping hand for gripping a workpiece, a plurality of rotating shafts arranged on the same circumference, a drive unit for transmitting rotation to these rotating shafts, and an arm fixed to each rotating shaft In addition, there has been proposed a robot gripping hand provided with a chuck member provided at the tip of each arm and protruding in the axial direction of the rotation shaft. The chuck member can be moved not only to the inner peripheral side of the circumference on which the rotation shaft is arranged, but also to the outer peripheral side, and the limit of the outer dimension of the work that can be gripped is small. In addition, each chuck member can be driven only by rotating each rotating shaft (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 11-333776 (paragraphs 0006 to 0010 and FIG. 1)

  Since a conventional robot gripping hand for gripping a workpiece is configured as described above, when gripping an elongated workpiece such as a shaft, the upper end of the shaft is pinched with a chuck member, and the posture is like hanging. There is a problem that it is difficult to stably hold the robot when the robot operates. In the unlikely event that the power is cut off, there is also a problem that the gripping force is lost and the workpiece falls.

  Accordingly, an object of the present invention is to obtain a robot gripping hand capable of stably gripping articles having various shapes and dimensions.

  A gripping hand for a robot according to the present invention includes a base having a center axis and an opening that can receive an article disposed along the center axis, and is rotatably supported on the base. At least three rotating shafts having axial centers extending along the axial center and arranged at equal angular intervals on a pitch circle concentric with the central axial center; a driving device for driving the rotating shaft; and A rotating gripping finger is attached to a rotating shaft and rotates together with the rotating shaft, and a movable gripping finger is provided at an open position in which the mutual interval is opened or a closed position in which the mutual interval is narrowed. It is arrange | positioned in the position which does not interfere with the articles | goods received in an opening part.

  According to the robot gripping hand of the present invention, articles having various shapes and dimensions can be stably gripped.

Embodiment 1 FIG.
1 to 10 show an embodiment of a robot gripping hand of the present invention. As shown in FIGS. 1 and 2, the robot gripping hand of the present invention has a base 3 having a central axis 1 and an opening 2 that can receive an article disposed along the central axis 1. At least three rotations each having an axis 5 that is rotatably supported on the base 3 and that extends along the central axis 1 and is spaced equiangularly on a pitch circle 4 concentric with the central axis 1. A shaft 6 and a driving device 7 for driving the rotating shaft 6 are provided. Here, the axis 5 of the rotary shaft 6 extends “along” the central axis 1 or the article is arranged “along” the central axis 1. It represents that it is parallel or inclined with respect to the axis 1 and extends in the direction of the central axis 1 as a whole.

  In the illustrated example, the base 3 is arranged in parallel with each other by three rods 8 and is connected to each other, and each of the bases 3 has a circular first opening 9 and a second opening 10 concentric with the central axis 1. 11 and a second substrate 12. One end of a hollow cylinder 13 concentric with the second opening 10 is coupled to the second substrate 12 on the surface opposite to the first substrate 11, and the other end of the hollow cylinder 13 is illustrated. A mounting flange 14 is provided on a wrist portion of the robot body that is not connected to the robot body by a bolt (not shown) or the like. For this reason, in this robot gripping hand, the side with the first substrate 11 is called the front end side, and the side with the mounting flange 14 is called the rear end side.

  In the base 3 configured in this way, the first and second openings 9 and 10 and the internal space of the hollow cylindrical body 13 constitute the opening 2, and as described later, the base as a whole 3, arranged along the central axis 1, ie concentrically parallel to the central axis 1, parallel or slightly inclined, etc. Yes. The article is an article handled by a robot gripping hand for processing, assembly, movement, etc., and includes various shapes and sizes as will be described later. At least a portion of the article can be received.

  In the example shown in the figure, three rotation shafts 6 are provided, and each of the rotation shafts 6 is rotatably attached to the first substrate 11 by a bearing. The axis 5 of the rotating shaft 6 is parallel to the center axis 1 of the base 3 and is spaced 120 degrees from each other on the pitch circle 4.

  A driving device 7 is connected to the rotating shaft 6. That is, a pulley 15 is attached to each rotary shaft 6 at the end on the rear end side of the first substrate 11, and a timing belt 17 whose tension is adjusted by an idler 16 is wound around the pulley 15. In addition, the three rotary shafts 6 perform the same rotational operation. The idler 16 is provided on the rod 8 connecting the first and second substrates 11 and 12 via a tension adjusting device 18. Further, one of the three rotation shafts 6 (the rotation shaft 6 on the right front side in FIG. 1) is attached to the rear end side of the second substrate 12 by the coupling 19 on the rear end side further than the pulley 15. It is connected with the output shaft 20a of the drive machine 20 which is a motor. Thus, in the illustrated example, the driving device 7 that rotates the rotating shaft 6 includes the pulley 15, the idler 16, the timing belt 17, the coupling 19, and the driving machine 20. Since the pulley 15, the idler 16, and the timing belt 17 are all located outside the opening 9, it does not prevent the workpiece from entering the opening 9. As described above, all the mechanisms including the rotating shaft 6 and the driving device 7 attached to the base 3 are arranged at positions that do not interfere with the articles received in the opening 2 of the base 3.

  Each of the robot gripping hands is attached to the rotating shaft 6 with its tip eccentric, and rotates together with the rotating shaft 6. As shown in FIGS. 3 and 4, the tips are opened and spaced apart from each other. 5 or 6, or the movable gripping finger 21 at the closed position where the tip is closed and the distance between the two is smaller than the first distance, as shown in FIGS. 5 and 6. I have.

  The gripping finger 21 has one end fixed to the end of the rotating shaft 6 protruding from the first substrate 11 and extending in a direction perpendicular to the axis 5 of the rotating shaft 6, and a finger A claw portion 23 extending from the other end of the portion 22 along the central axis 1 toward the distal end side of the robot gripping hand. That is, the claw part 23 is attached to the finger part 22 at a position eccentric with respect to the rotation shaft 6. The claw portion 23 extends in parallel with the central axis 1 in the illustrated example, and is made of a material having high friction such as rubber, and has an axis 24 parallel to the axis 5 of the rotary shaft 6. In addition, the cylindrical member has a diameter larger than the width of the tip of the finger portion 22. In the illustrated example, the claw portion 23 is constituted by two cylindrical elements provided on both front and rear sides of the finger portion 22 by a shaft 25 penetrating the tip of the finger portion 22.

  3 to 6 show an example of the opening / closing operation of the robot gripping hand of the present invention. 3 and 4, the rotating shaft 6 (the right rotating shaft 6 in FIG. 3) connected to the output shaft 20 a is driven by the rotation of the driving device 20 that is a motor with a speed reducer. The rotation of the rotary shaft 6 is simultaneously transmitted to the other rotary shafts 6 via the pulley 15 and the timing belt 17, and the three rotary shafts 6 are rotated synchronously, and the three gripping fingers 21 are moved. Synchronously rotating in the same direction, the distance between the claw portions 23 is increased and held in the open position shown in the figure. In the open position shown in FIG. 3, the claw portion 23 of the gripping finger 21 is outside the pitch circle 4 on which the rotation shaft 6 is arranged. If the rotating shaft 6 is further rotated clockwise in the figure, the distance between the claw portions 23 can be set to the open position.

  When the driving machine 20 is rotated to another position, the three gripping fingers 21 provided on the rotary shaft 6 correspondingly rotate by the same amount in the same direction, and the example shown in FIGS. 5 and 6 Then, by rotating counterclockwise from the open position of FIGS. 3 and 4, the distance between the claw portions 23 of the gripping fingers 21 is reduced to the closed position shown in FIGS. If the gripping finger 21 is further rotated counterclockwise in the figure, the claw portions 23 can be brought into a closed position in contact with each other.

  FIGS. 7 to 10 show examples of gripping work for showing how the robot gripping hand of the present invention can grip articles of various shapes and dimensions. FIG. 7 shows an example in which a large-diameter drum-shaped article 31 is gripped. One of the circular planes of the article 31 faces or is close to the finger portion 22 of the gripping finger 21, and the peripheral surface is The gripping finger 21 is gripped by friction with the gripping finger 21 while in contact with the nail portion 23 of the gripping finger 21. By opening the gripping finger 21 as shown in the figure, for example, an article such as the article 31 that is larger than the pitch circle and has a relatively large diameter with respect to the size of the robot gripping hand itself can be stably gripped. When the gripping finger 21 reaches the closed position shown in the figure and the article 31 is gripped, an inward radial force of the article due to elasticity acts from the claw part 23 of the gripping finger 21, and the article 31 and the claw part 23 A frictional force is obtained in the meantime, and a gripping action is obtained. However, in order to ensure gripping of the article 31, it is desirable to continue energizing the drive unit 20 while gripping.

  FIG. 8 shows an example in which a long shaft-shaped article 32 having a diameter smaller than the pitch circle is held. In the case of such a long article 32, since the opening 2 is provided in the center of the base 3, the long article 32 can be "held" into the inside of the hand. With one end of 32 inserted into the opening 2 to grip the center and the other end protruding, gripping a position close to the center of gravity ensures stable gripping even when the robot operates and a reaction force is applied. Is possible.

  FIG. 9 shows an example in which a hollow cylindrical article 35 is fitted into a fixed long article 34 erected on a large component 33. In the robot gripping hand according to the present invention, the distal end portion of the long article 34 can be received in the opening 2 of the base 3 and “clamped”. It can reach the root.

FIG. 10 shows an example in which the annular article 36 is gripped from the inside by the claw portion 23 of the gripping finger 21 on the inner peripheral surface portion. In this case, after the gripping finger 21 is once in the closed position and the claw portion 23 is inserted into the inner peripheral surface of the article 36, the gripping finger 21 is in the open position and “gripped”.
Although the example in which the finger portion 22 extends in a direction perpendicular to the axis 5 of the rotation shaft 6 is shown, the finger portion 22 may not be at a right angle. What is necessary is just to be able to support it eccentrically.

Embodiment 2. FIG.
Since the basic configuration of the robot gripping hand of the present invention shown in FIGS. 11 to 13 is the same as that shown in FIGS. 1 to 10, FIGS. 11 to 13 show the robot gripping hand, the base 3 and the driving device 7. Etc. are omitted, and only the portions of the gripping finger 21 and the rotary shaft 6 are extracted and drawn. In this robot gripping hand, all of the axes 5 of the rotation shaft 6 are not parallel to the center axis 1 of the base 3 but are inclined and intersect at a point 37 on the center axis 1. Accordingly, the drive unit 20, the pulley 15, the finger portion 22 of the gripping finger 21, and the claw portion 23 attached to the rotating shaft 6 are also inclined corresponding to the inclination of the axis 5 of the rotating shaft 6. Other configurations are the same as those shown in FIGS.

  FIG. 12 shows a state in which the cylindrical article 38 is gripped by the robot gripping hand. In the same manner as in the first embodiment, the rotary shaft 6 is driven by a drive unit 20 (not shown) that is a motor and the gripping finger 21 is closed to grip the article 38. The article 38 is gripped by the friction between the claw portion 23 and the article 38.

  FIG. 13 is a diagram in which the state of FIG. 12 is projected onto a plane perpendicular to the axis 25 of the nail portion 23 of one gripping finger 21. In FIG. 13, the robot gripping hand is looked down from above, and the upper left in the figure corresponds to the lower side. V1 is a vector obtained by projecting the load vector of the article 38 applied to the claw 23 at the contact point 39 between the claw 23 and the article 38 onto the projection plane of FIG. V2 is a component that contributes to the rotation of the gripping finger 21 in the load of V1. By the action of V2, the gripping finger 21 receives a clockwise moment around the rotation axis 6 in the figure. Since the same holds true for the other gripping fingers 21, a gripping force in the closing direction is generated in the gripping finger 21 due to the weight of the article 38. For this reason, there is an effect that the article 38 does not easily fall off even if the driving force of the drive unit 20 that is a motor with a speed reducer is lost due to power interruption.

  The angle at which the rotating shaft 6 is attached to the base axis 1 of the base 3 (not shown) is arbitrary between 0 degrees and 90 degrees, but if this angle is large, the driving force of the driving machine 20 is increased. Transmission by the pulley 15 and the timing belt 17 becomes difficult. In this case, for example, the direction of the rotary shaft 6 may be parallel to the central axis 1 by a universal joint.

  In contrast to FIG. 11, when the axis 5 of the rotary shaft 6 is tilted so that it intersects the central axis 1 of the base 3 at one point below the hand, the gripping force in the direction in which the gripping finger 21 opens is increased. Therefore, it is possible to provide a robot gripping hand corresponding to the case of inner diameter gripping as shown in FIG.

  Further, the robot gripping hand in which the axis 5 of the rotating shaft 6 intersects the central axis 1 of the base 3 at a point 37 above the hand, and the center 5 of the base 3 below the robot gripping hand. By combining hands that intersect one point with one point up and down, it is possible to obtain a hand capable of both outer diameter gripping as shown in FIG. 7 and inner diameter gripping as shown in FIG.

  The robot gripping hand illustrated and described above is merely an example, and various modifications can be made, and the features of each specific example can be used altogether or selectively combined. For example, the drive control of the drive unit 20 that is a motor with a speed reducer can be performed by force control, for example, to adjust the gripping force. The position where the shaft 6 is slightly rotated is controlled as a target value, and when the target value of the position is changed, the amount of elastic deflection of the claw portion 23 changes and the generated force changes indirectly. May be adjusted.

  The drive unit 20 that is a motor drives all three rotary shafts 6 directly or indirectly, but does not necessarily connect to the rotary shaft 6 and drives the pulley 15, the idler 16 or the timing belt 17. You can also. Moreover, although the example which used the drive machine 20 which is a motor with a reduction gear as a means to rotate the rotating shaft 6 was shown, other drive means, such as a motor without a reduction gear, may be sufficient. Alternatively, a worm gear may be used as a speed reducer so that it can continue to be gripped even if the driving force of the motor is lost due to power-off due to self-locking.

  Further, the rotating shaft 6 can be arranged parallel to the central axis 1, the finger portion 22 of the gripping finger 21 can be perpendicular to the rotating shaft 6, and only the axis 24 of the claw portion 23 can be inclined.

  Furthermore, as an article to be gripped by the robot gripping hand, an article having a circular cross section as shown in FIGS. 7 to 10 has been described as an example. You can also.

It is a perspective view which shows the holding hand for robots by Embodiment 1 of this invention. It is explanatory drawing which shows the relationship of the timing belt etc. of the holding | grip hand for robots of FIG. It is a perspective view which shows the state which has the holding | grip hand for robots of FIG. 1 in an open position. FIG. 4 is a bottom view of the robot gripping hand of FIG. 3. It is a perspective view which shows the state which has the holding | grip hand for robots of FIG. 1 in a closed position. FIG. 5 is a bottom view of the robot gripping hand of FIG. 4. It is a perspective view which shows the case where an article | item is large diameter as an example of the holding | grip operation | work by the robot holding hand of FIG. It is a perspective view which shows the case where an article | item is elongate as an example of the holding | grip operation | work by the robot holding hand of FIG. It is a perspective view which shows the case where an article | item should be deeply inserted deeply as an example of the holding | grip operation | work by the robot holding hand of FIG. It is a perspective view which shows the case where an article | item is a cyclic | annular body as an example of the holding | grip operation | work by the robot holding hand of FIG. It is a schematic perspective view which shows the holding hand for robots by Embodiment 2 of this invention. It is a schematic perspective view which shows the state which the holding hand for robots of FIG. It is a perspective view which shows the relationship of the load of the gripping hand for robots in the gripping hand for robots of FIG.

Explanation of symbols

  1 center axis, 2 openings, 3 base, 4 pitch circle, 5 axis, 6 rotation axis, 7 drive unit, 15 pulley, 17 belt, 20 drive machine, 21 gripping finger, 22 finger part, 23 claw part, 31, 32, 34-36, 38 Article, 37 One point.

Claims (6)

A base having a central axis and an opening capable of receiving an article disposed along the central axis;
At least three rotating shafts each supported rotatably on the base, extending along the central axis, and having axes arranged at equal angular intervals on a pitch circle concentric with the central axis; ,
A driving device for driving the rotating shaft;
Each is attached to the rotating shaft and rotates together with the rotating shaft to move to an open position where the distance between them is the first distance or a closed position where the distance between them is a second distance smaller than the first distance. And holding fingers
A gripping hand for a robot, wherein the rotating shaft and the driving device are arranged at positions that do not interfere with an article received in the opening.   The drive device is coupled to at least one of a pulley provided on the rotating shaft, a belt that is wound around the pulley and synchronously rotates the pulley, and the rotating shaft, the pulley, and the belt. The robot gripping hand according to claim 1, further comprising a driving device.   The robot gripping hand according to claim 2, wherein the driving machine is connected to the rotating shaft.   The gripping finger is attached to the finger part at a position eccentric from the rotation axis, a finger part extending from the rotation axis in a direction perpendicular to the center axis or at least in a direction not parallel to the center axis, The robot gripping hand according to any one of claims 1 to 3, further comprising a claw portion extending along a central axis.   The robot gripping hand according to any one of claims 1 to 4, wherein all of the axes of the rotation shafts are parallel to the center axis.   The robot gripping hand according to any one of claims 1 to 4, wherein all of the axes of the rotating shafts intersect at one point on the center axis.

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