JP2009000768A - Workpiece gripping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a workpiece gripping device capable of simultaneously and firmly gripping a plurality of laminated workpieces. <P>SOLUTION: The gripping device 1 is equipped with a plurality of cylindrical collets 11 arranged in line, a plurality of cylindrical blocks 12 arranged among a plurality of the collets 11, and a pressing device 20 inserted with a plurality of the collets 11 and the blocks 12 for clipping a plurality of the collets 11 and the blocks 12 from both end sides and pressing. An outer diameter of the block 12 is larger than an inner diameter of the collet 11 at the center part, becomes smaller with going from the center part to the both end parts, and becomes smaller than the inner diameter of the collet 11 at the both end parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a workpiece gripping device. Specifically, the present invention relates to a workpiece gripping device that grips a workpiece in which a hole is formed.

Conventionally, a front wheel assembly of a motorcycle is composed of a pair of front forks, a stem, a wheel, a brake panel, an axle, and the like. Among these parts, through holes are formed in the front fork, the stem, the wheel, and the brake panel.
The assembly of the front wheel part is assembled manually. That is, a pair of front forks are arranged in parallel and fixed with a stem, and a brake panel is attached to the wheel. The wheel to which the brake panel is attached is arranged between the front forks, and the through holes of the wheel and the brake panel are arranged coaxially with the through holes of the front fork. Thereafter, the axles are inserted into these through holes and tightened. As a result, the wheel and the brake panel are rotatably attached to the front fork with the axle as the rotation axis.

Incidentally, in recent years, in order to reduce manufacturing costs, it has been required to assemble the above-described front wheel assembly using a robot. In view of this, a conveying device that holds a workpiece in which a hole is formed has been proposed (see Patent Document 1).
That is, the transport device disclosed in Patent Document 1 includes a center plug that is inserted into a hole of a workpiece, and an inflatable rubber tube is externally mounted on the center plug.
According to this transport device, the center plug is inserted into the hole of the work and the rubber tube is expanded, so that the center plug is locked to the hole of the work and the work can be held.
JP 2002-210689 A

However, even if it is going to assemble the above-mentioned assembly using the conveyance device shown in patent documents 1, in this conveyance device, since only one part can be grasped at a time, the parts which constitute an assembly cannot be assembled efficiently. Have difficulty.
Moreover, in this conveyance apparatus, since a workpiece | work is hold | maintained with the expansion force of a rubber tube, it is difficult to hold | maintain a workpiece | work firmly.

  It is an object of the present invention to provide a workpiece gripping device that can grip a plurality of workpieces arranged in a stacked manner simultaneously and firmly.

  The workpiece gripping device (for example, a gripping device 1 described later) of the present invention includes a plurality of cylindrical collets (for example, a collet 11 described below) arranged in a row and a plurality of collets disposed between the plurality of collets. A cylindrical piece (for example, a piece 12 described later) and a pressurizing means (for example, a pressure described later) inserted through the plurality of collets and pieces and sandwiching the plurality of collets and pieces from both ends. The outer diameter of the piece is larger at the central portion than the inner diameter of the collet and becomes smaller from the central portion toward both ends, and at the both end portions, smaller than the inner diameter of the collet. It is characterized by becoming.

According to this invention, the workpiece in which the hole is formed is gripped by the following procedure.
That is, a plurality of collets are arranged in a line, and a piece is arranged between these collets. Since both ends of the piece are smaller than the inner diameter of the collet, both ends of the piece enter the inside of the collet.
First, the workpiece gripping device is inserted into the hole of the workpiece without being pressurized by the pressing means, and the collet is positioned inside the workpiece hole. In this state, since the collet is not expanded, the collet can be smoothly inserted into the hole of the workpiece.

Next, when pressure is applied by the pressurizing means, the two pieces located on both sides of each collet advance toward the inside of the collet, and the interval between the adjacent pieces is shortened. Then, since the outer diameter of the central part of the piece is larger than the inner diameter of the collet, the inner wall surface of the collet is expanded, the collet is elastically deformed, and the outer diameter of the collet is expanded.
Therefore, the collet presses the inner wall surface of the hole of the workpiece, and the workpiece is gripped by the frictional force between the inner wall surface of the hole of the workpiece and the outer peripheral surface of the collet.

  After that, when the pressurization by the pressurizing means is released, the piece is pressed by the inner wall surface of the collet due to the restoring force of the elastic deformation of the collet, and this piece moves backward toward the outside of the collet. The outer diameter contracts and returns to the original outer diameter. Therefore, the pressing force of the collet against the inner wall surface of the workpiece hole is released, and the workpiece can be released.

  In the present invention, since each collet performs the above operation independently, a plurality of stacked workpieces can be gripped simultaneously. Further, by using the collet, the workpiece can be firmly held as compared with the conventional rubber tube. Furthermore, even if the inner diameters of the workpiece holes are different, the workpiece can be reliably gripped, and the workpiece gripping device is configured by the collet, the piece, and the pressurizing means, so that the configuration is simple and the cost is low.

  According to the present invention, since each collet operates independently, a plurality of stacked workpieces can be gripped simultaneously. Further, by using the collet, the workpiece can be firmly held as compared with the conventional rubber tube. Furthermore, even if the inner diameters of the workpiece holes are different, the workpiece can be reliably gripped, and the workpiece gripping device is configured by the collet, the piece, and the pressurizing means, so that the configuration is simple and the cost is low.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a schematic configuration of a gripping device 1 to which a workpiece gripping device according to an embodiment of the present invention is applied. FIG. 2 is a side view of the gripping device 1.
The gripping device 1 is a robot hand, and is provided at the tip of an arm (not shown) that changes the posture of the gripping device 1 and the position in the three-dimensional space.

  The gripping device 1 includes a plurality of cylindrical collets 11 arranged in a row, a plurality of cylindrical pieces 12 arranged between the plurality of collets 11, and the collet 11 and the pieces 12 sandwiched from both ends. And a pressurizing device 20 as a pressurizing means for pressurizing at.

  The plurality of collets 11 are arranged so that the central axes are coaxial, and the pieces 12 are arranged between the collets 11 so that the central axes are coaxial with the collets 11. That is, the collet 11 and the piece 12 are alternately arranged on a straight line.

FIG. 3A is an exploded perspective view of a part of the gripping device 1. FIG. 3B is a partial cross-sectional view of the gripping device 1.
In the collet 11, slits 111 extending from the vicinity of one end edge to the other end edge and slits 112 extending from the vicinity of the other end edge to the one end edge are alternately formed.

  The outer diameter of the piece 12 is larger at the center than the inner diameter of the collet 11 and decreases from the center toward both ends, and at both ends, the outer diameter is smaller than the inner diameter of the collet 11. Therefore, since both ends of the piece 12 are smaller than the inner diameter of the collet 11, both ends of the piece 12 are in a state of entering the inside of the collet 11.

  Returning to FIGS. 1 and 2, the pressing device 20 includes a gripping flange 22 supported by an arm and formed with a through hole 21, and a pressing pin inserted through the through hole 21 and into the collet 11 and the piece 12. And an actuator 24 that is provided on the gripping flange 22 and moves the pressure pin 23 forward and backward.

The gripping flange 22 includes a flat plate 221 and a first pressurizing unit 222 integrally formed at the center of the plate 221. The first pressurizing unit 222 has a shape in which the piece 12 is halved. That is, the outer diameter of the first pressurizing part 222 is larger than the inner diameter of the collet 11 on the plate 221 side, and becomes smaller toward the tip part, and is smaller than the inner diameter of the collet 11 at the tip part.
The above-described through hole 21 is formed so as to penetrate the plate 221 and the first pressure unit 222.

A second pressure member 231 having the same shape as the piece 12 is integrally formed at the tip of the pressure pin 23.
The actuator 24 moves the pressure pin 23 forward and backward, and is controlled by a control unit (not shown).

  According to the pressurizing device 20, the pressurizing pin 23 is moved backward, and the first pressurizing unit 222 and the second pressurizing unit 231 press the collet 11 and the piece 12 from both ends.

Next, the operation of the gripping device 1 will be described.
When the actuator 24 is not operated, both end sides of the piece 12 enter the collet 11, but the collet 11 is not expanded because it is not pressurized.

Next, as shown in FIG. 4, the actuator 24 is operated, and the pressure pin 23 is moved backward by the applied pressure F. Then, the first pressurizing unit 222 and the second pressurizing unit 231 pressurize the collet 11 and the piece 12 with the applied pressure F. This pressurizing force F is transmitted through each collet 11 and each piece 12 and acts equally on all the collets 11 and pieces 12.
For example, the collet 11A in FIG. 4 will be described. Two pieces 12A located on both sides of the collet 11A advance toward the inside of the collet 11A, and the interval between the adjacent pieces 12A is shortened. Then, since the outer diameter of the central part of the piece 12A is larger than the inner diameter of the collet 11A, the outer peripheral surface of the piece 12A presses the inner wall surface of the collet 11A in the direction of arrow A as shown in FIG. As a result, the collet 11A is elastically deformed, and the outer diameter of the collet is expanded in the direction of arrow B as shown in FIG.

  Therefore, when the gripping device 1 is inserted into the hole of the workpiece and the actuator 24 is operated, the collet 11 presses the inner wall surface of the hole of the workpiece, and the inner wall surface of the hole of the workpiece and the outer peripheral surface of the collet 11 The workpiece can be gripped by the frictional force.

  Thereafter, when the pressurization by the pressurizing device 20 is released, the piece 12 is pressed by the inner wall surface of the collet 11 by the restoring force of the elastic deformation of the collet 11, and the piece 12 moves backward toward the outside of the collet 11. At the same time, the outer diameter of the collet 11 contracts and returns to the outer diameter. Therefore, the pressing force of the collet 11 against the inner wall surface of the hole of the workpiece is released, and the workpiece can be released.

Next, the operation in the case of gripping the three workpieces 30B, 30C, and 30D arranged in a stacked manner using the gripping device 1 will be described with reference to FIGS.
A through hole 31B is formed in the work 30B, and the inner diameter of the through hole 31B is d1. The work 30C is disposed on the work 30B, and a through hole 31C is formed. The inner diameter of the through hole 31C is d2 which is larger than d1. The work 30D is disposed on the work 30C, and a through hole 31D is formed. The inner diameter of the through hole 31D is d3 which is larger than d2.

First, as shown in FIG. 7, the gripping device 1 is controlled so that the collets 11B, 11C, and 11D are disposed inside the through holes 31B, 31C, and 31D of the workpieces 30B, 30C, and 30D, respectively. In this state, the outer diameters of the collets 11B, 11C, and 11D are d0.
Next, when a pressurizing force is applied by the pressurizing device 20 and the pressurizing force is increased, all the collets 11 including the collets 11B, 11C, and 11D start to expand simultaneously.

  When the applied pressure is further increased, as shown in FIG. 8, the outer diameters of all the collets 11 become d1, and the collets 11B come into contact with the inner wall surfaces of the through holes 31B of the workpiece 30B.

When the pressing force F is further increased, as shown in FIG. 9, the outer diameter of the remaining collet 11 excluding the collet 11B becomes d2, and the collet 11C comes into contact with the inner wall surface of the through hole 31C of the workpiece 30C.
In this state, the outer diameter of the collet 11B is d1, but the gripping pressure of the collet 11B against the inner wall surface of the work 30B hardly increases. This is because the collet 11 other than the collet 11B is in an expandable state, so that the pressure applied to the collet 11B escapes.

  Thereafter, when the pressing force F is further increased, as shown in FIG. 10, the outer diameter of the remaining collet 11 excluding the collets 11B and 11C becomes d3, and the collet 11D contacts the inner wall surface of the through hole 31D of the workpiece 30D. Touch.

  Thereafter, when the pressing force F is further increased, as shown in FIG. 11, the outer diameters of the remaining collets 11 except for the collets 11B, 11C, and 11D become d4, the pieces 12 come into contact with each other and the expansion stops. The gripping pressures of the collets 11B, 11C, and 11D increase rapidly. At this time, since the pieces 12 come into contact with each other, the collet 11 that is not used for gripping the workpieces 30B to 30D is not excessively expanded.

According to this embodiment, there are the following effects.
(1) Since each collet 11 operates independently, a plurality of stacked workpieces 30B, 30C, and 30D can be gripped simultaneously. In addition, by using the collet 11, the workpieces 30B, 30C, and 30D can be firmly held as compared with the conventional rubber tube. Further, even if the inner diameters of the through holes 31B, 31C, and 31D of the workpieces 30B, 30C, and 30D are different, the workpieces 30B, 30C, and 30D can be securely gripped, and are gripped by the collet 11, the piece 12, and the pressure device 20. Since the apparatus 1 is configured, the configuration is simple and the cost is low.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

1 is a perspective view illustrating a schematic configuration of a gripping device to which a workpiece gripping device according to an embodiment of the present invention is applied. It is a side view of the holding | gripping apparatus which concerns on the said embodiment. It is a partial exploded perspective view and sectional view of a grasping device concerning the above-mentioned embodiment. It is a figure which shows the state which applied the applied pressure to the holding | gripping apparatus which concerns on the said embodiment. It is a figure which shows the state which applied the applied pressure about one collet of the holding | grip apparatus which concerns on the said embodiment. It is a figure which shows the expanded state about one collet of the holding | grip apparatus which concerns on the said embodiment. It is a figure which shows the state before hold | grip the three laminated | stacked workpiece | work with the holding | grip apparatus which concerns on the said embodiment. It is a figure which shows the state which hold | gripped the lower stage workpiece | work with the holding | gripping apparatus which concerns on the said embodiment. It is a figure which shows the state which hold | gripped the workpiece | work of the lower stage and the middle stage with the holding | grip apparatus which concerns on the said embodiment. It is a figure which shows the state which hold | gripped all the workpiece | work with the holding | gripping apparatus which concerns on the said embodiment. It is a figure which shows the state after hold | gripping all the workpiece | work with the holding | grip apparatus which concerns on the said embodiment.

Explanation of symbols

1 Gripping device (work gripping device)
11, 11A, 11B, 11C, 11D Collet 12, 12A piece 20 Pressure device

Claims (1)

A plurality of cylindrical collets arranged in a row;
A plurality of cylindrical pieces arranged between the plurality of collets;
A pressurizing means that is inserted through the plurality of collets and pieces and pressurizes the plurality of collets and pieces from both end sides; and
The outer diameter of the piece is larger at the center than the inner diameter of the collet, and decreases from the center toward both ends, and at both ends, the workpiece gripping is smaller than the inner diameter of the collet. apparatus.

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