JP5278738B2 - 4-jaw chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a four-claw chuck with a small and simple structure. <P>SOLUTION: A front piston 11 driving clamping claws 3 is inserted in a front cylinder chamber 9 arranged in a chuck body 2, and a rear piston 12 is inserted in a rear cylinder chamber 10. The front cylinder chamber 9 and the clamp side cylinder chamber 10a of the rear cylinder chamber 10 are communicated by a flow passage 16 for clamping. In an unclamped condition, a pressure fluid is supplied to an unclamped side cylinder chamber 10b to make the rear piston 12 contacted with the front piston 11 and retracted integrally, thereby unclamping the respective clamping claws 3. The unclamped side cylinder chamber 10b is provided only in the rear piston 12. That enables downsizing of the chuck 1 and simplification of the structure. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention inserts a front piston and a rear piston into the front cylinder chamber and the rear cylinder chamber provided in the chuck body, respectively, and moves the driving members provided in the front piston and the rear piston, respectively, so as to be arranged on the front side of the chuck body. The present invention relates to a four-claw chuck formed by moving opposing gripping claws.

Conventionally, as a four-jaw chuck, the two pairs of opposing grasping claws arranged on the chuck body front respectively driven, there is intended to clamp the vertical surfaces of the rectangular workpiece and the left-right direction plane. In such a four-claw chuck, a front piston and a rear piston are inserted into a front cylinder chamber and a rear cylinder chamber provided in the chuck body, respectively. Drive members for moving the gripping claws are connected to the front piston and the rear piston, respectively. When there is a difference between the vertical length and the horizontal length of a rectangular workpiece, when clamping the rectangular workpiece, the front piston and the rear piston differ and one set of opposing gripping claws is rectangular. After abutting against the workpiece, the other pair of opposing gripping claws abuts against the rectangular workpiece, so that each pair of opposing gripping claws moves according to the length of the workpiece, and two sets The workpiece is clamped by gripping claws facing each other.

  Patent Documents 1 and 2 are well-known as the four-jaw chuck. In the four-jaw chuck of Patent Document 1, when clamping a rectangular workpiece, a pressure fluid (compressed air) is supplied to each clamp-side cylinder chamber of the front cylinder chamber and the rear cylinder chamber with a time difference depending on the operation system. The one set of opposing gripping claws and the other set of opposing gripping claws are operated with a time difference, and a rectangular workpiece is clamped by providing a difference between the thrust of the front piston and the thrust of the rear piston. . During unclamping, pressure fluid is simultaneously sent to the unclamping cylinder chambers of the front cylinder chamber and the rear cylinder chamber to move the front piston and the rear piston to unclamp each pair of opposing gripping claws. doing.

Further, in the four-jaw chuck of Patent Document 2, a rectangular work (rectangular square hole) is transferred to the front cylinder chamber and the clamping cylinder chambers (first and third cylinder chambers) of the rear cylinder chamber (oil). ) Is moved to clamp each pair of opposing gripping claws via the front piston (drive ring) and the rear piston (drive member). Further, at the time of unclamping, the front piston is moved by the urging force of the coil spring, oil is supplied to the unclamping cylinder chamber (second cylinder chamber) of the rear cylinder chamber, and the rear piston is moved, so that each pair The gripping claws facing each other are unclamped.
Japanese Examined Patent Publication No. 2-17284 JP 7-266112 A

However, in the four-jaw chuck described in Patent Document 1, when a workpiece is clamped and unclamped, a pressure fluid is supplied to each of the clamp-side cylinder chamber and the unclamp-side cylinder chamber of the front cylinder chamber and the rear cylinder chamber, respectively. Since the piston and the rear piston are moved to move each pair of opposing gripping claws, the four cylinder chambers of the front cylinder chamber and the rear cylinder chamber, ie, the clamp side cylinder chamber and the unclamp side cylinder chamber are connected to the chuck body. There are problems that the structure is complicated and the length in the chuck axis direction is long. In addition, the operating system for supplying the pressurized fluid that moves the front piston and the rear piston has a problem that the structure is complicated because the front piston and the rear piston are moved with a time difference provided outside the chuck . Further, in the four-claw chuck described in Patent Document 2, each opposing pair of grasping claws is moved and unclamped by the movement of the front piston by the coil spring and the movement of the rear piston by the pressurized fluid. Since the chuck body has a structure for unclamping the system, there is a problem that the structure becomes complicated.
Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a small and simple four-jaw chuck.

In order to achieve the above object, according to a first aspect of the present invention, a front piston and a rear piston are respectively inserted into a front cylinder chamber and a rear cylinder chamber provided in a chuck body, and a front portion of the rear piston is connected to the front piston. The front piston and the rear piston are inserted into the inner diameter part, and driving members are provided on the front piston and the rear piston, respectively. By moving the front piston and the rear piston, the respective driving members are moved to move the two opposing gripping claws arranged on the front side of the chuck body. In the four-claw chuck, the clamping fluid is supplied to the chuck main body and the clamping cylinder in the front cylinder chamber and the rear cylinder chamber, and the pressure fluid is supplied to the unclamping cylinder chamber in the rear cylinder chamber. An unclamping flow path is provided, and when the workpiece is unclamped, the rear piston is moved backward by supplying pressurized fluid from the unclamping flow path. So as to move the front piston to the rear part of the driving member provided on the piston in contact, characterized by comprising. According to a second aspect of the present invention, the drive member is provided on the rear piston so that the rear surface of the drive member can come into contact with the front surface of the front piston. The invention described in claim 3 is characterized in that the diameters of the front piston and the rear piston are made the same, and the areas of the pressure fluid working surfaces of the front piston and the rear piston are made the same.

In the invention of claim 1 of the present application, the clamping fluid is supplied to the chuck body for supplying the pressurized fluid to the clamping cylinder chambers of the front cylinder chamber and the rear cylinder chamber, and the pressurized fluid is supplied to the unclamping cylinder chamber of the rear cylinder chamber. An unclamping flow path is provided, and when the workpiece is unclamped, the rear piston is moved backward by supplying pressurized fluid from the unclamping flow path, and a part of the driving member provided on the rear piston is brought into contact with the front piston. The piston was moved backward. In the invention of claim 2 of the present application, the rear piston is provided with the drive member so that the rear surface of the drive member can come into contact with the front surface of the front piston. In the invention according to claim 3, the diameters of the front piston and the rear piston are made the same, and the areas of the pressure fluid working surfaces of the front piston and the rear piston are made the same. According to these, since the front piston is moved rearward by the rear piston at the time of unclamping, each pair of opposing gripping claws can be moved simultaneously after the rear piston and the front piston are brought into contact with each other. Can be unclamped in one operation by supplying a pressurized fluid. In addition, the front cylinder chamber is only connected to a clamp flow path communicating with the rear cylinder chamber, and the front cylinder chamber includes a cylinder chamber for clamping only on one side of the front piston. Compared with a cylinder chamber for clamping and unclamping on both sides of the chuck body, the chuck body can be downsized. That is, the length in the chuck axis direction is shortened. In addition, when the workpiece is unclamped, the drive member provided on the rear piston contacts the front piston and the front piston is moved together by the movement of the rear piston, so that the rear piston and the front piston are driven as usual. Therefore, it is not necessary to provide a cylinder chamber for unclamping or a coil spring for unclamping, and the structure of the chuck can be simplified. In addition, the front piston and the rear piston are arranged at the front and back by inserting the front part of the rear piston into the inner diameter part of the front piston so that the front piston and the rear piston have the same diameter. Since the two gripping claws have the same gripping force, the workpieces can be gripped evenly, and the strain of the workpiece becomes substantially equal. Further, since the unclamping cylinder chamber is not required in the front cylinder chamber, it is not necessary to increase the piston radially outward in order to provide the pressurized fluid working surface outside the outer peripheral surface of the front drive member. Can be reduced.

  An embodiment of the present invention will be described with reference to FIGS. The four-claw chuck 1 of this embodiment shown in FIGS. 1 and 2 is provided with four grasping claws 3 at equal intervals in the circumferential direction on the front side of the chuck body 2. The grasping claw 3 is formed by attaching a top jaw 5 to a master jaw 4, and the master jaw 4 is provided on the chuck body 2 so as to be movable in the chuck radial direction. The chuck body 2 is formed with a storage chamber 8 for storing a front drive member 6 and a rear drive member 7 which will be described later, and a front cylinder chamber 9 and a rear cylinder chamber 10 in the front and rear direction of the chuck axis. A front piston 11 and a rear piston 12 are slidably inserted into the front cylinder chamber 9 and the rear cylinder chamber 10, respectively. The front piston 11 has a rear portion inserted into the front cylinder chamber 9, making the front cylinder chamber 9 a clamp side cylinder chamber, and the front portion projects from the front cylinder chamber 9 into the accommodating chamber 8. Further, the rear piston 12 divides the rear cylinder chamber 10 into the unclamping cylinder chamber 10a and the rear side into the clamping cylinder chamber 10b with the rear piston 12 interposed therebetween. As shown in FIG. 2, the front piston 11 and the rear piston 12 have the same diameter, and the area (pressure receiving area) of the pressure fluid acting surface (pressure receiving surface) of the front piston 11 and the pressure fluid of the rear piston 12. The area of the working surface is the same.

  A front drive member 6 is formed integrally with the front piston 11, and the front drive member 6 forms a front portion. A rear drive member 7 is integrally connected to the rear piston 12, and the rear drive member 7 is a front portion of the rear piston 12. Each of the front drive member 6 and the rear drive member 7 has a claw engaging portion 15 in which a wedge groove 14 with which the wedge portion 13 of the master jaw 4 is engaged is formed. As shown in FIGS. 2 and 3, the shaft portion 7 a of the rear drive member 7 of the rear piston 12 is inserted into the inner diameter portion 6 a of the front piston 11 and can move relative to the front piston 11.

  The wedge portions 13 of the master jaw 4 of the four grasping claws 3 are engaged with the wedge grooves 14 of the front drive member 6 and the rear drive member 7, respectively. One set of opposing gripping claws 3a, 3a arranged on axes orthogonal to each other among the four gripping claws 3 can be moved in the chuck radial direction by the front driving member 6. The other pair of opposing gripping claws 3b, 3b arranged on axes orthogonal to each other among the four gripping claws 3 can be moved in the chuck radial direction by the rear drive member 7.

  The clamp-side cylinder chamber 10b of the front cylinder chamber 9 and the rear cylinder chamber 10 is connected to the same clamping channel 16 for supplying and discharging the pressurized fluid by a front supply / discharge channel 17 and a rear supply / discharge channel 18, respectively. Yes. The clamping channel 16 is provided in the chuck body 2. An unclamping channel 19 for supplying and discharging pressurized fluid is connected to the unclamping cylinder chamber 10 a of the rear cylinder chamber 10. The unclamping channel 19 is provided in the chuck body 2. One set of claw engaging portions 15 of the front drive member 6 are provided so as to protrude in the radial direction of the chuck and to face each other. Further, one set of claw engagement portions 15 of the rear drive member 7 is provided so as to face each other between a pair of claw engagement portions 15 opposed to the front drive member 6. The claw engaging portion 15 which is a part of the rear piston 12 is provided so as to protrude in the chuck radial direction, and the rear surface 15a of the claw engaging portion 15 of the rear piston 12 can come into contact with the front surface 11c of the front piston 11. It has become.

  Next, the operation of the chuck 1 will be described. As shown in FIG. 1, it is assumed that the workpiece W has a quadrangular cross section, the distance between the vertical surface and the distance between the horizontal surfaces is different, and the distance between the horizontal surfaces is long. When clamping the workpiece W, compressed air is supplied as a pressurized fluid from a pressurized fluid supply source (not shown). The supplied compressed air is supplied substantially simultaneously to the front cylinder chamber 9 and the clamp side cylinder chamber 10b of the rear cylinder chamber 10 through the clamp channel 16. At this time, the unclamping cylinder chamber 10a is open to the atmosphere. Since the front piston 11 and the rear piston 12 have the same pressure receiving area, the front piston 11 and the rear piston 12 move substantially simultaneously in the forward direction of the chuck axis, and one set of opposing gripping claws 3a, 3a clamps the workpiece W by the front drive member 6. The other pair of opposing gripping claws 3b, 3b are moved by the rear drive member 7 in the direction in which the workpiece W is clamped. When the workpiece W is clamped, the movement of the front drive member 6 is stopped when the pair of opposing gripping claws 3a, 3a come into contact with the left-right direction surface of the workpiece W by the front drive member 6.

  When the front drive member 6 is stopped, the pressurized fluid from the clamping channel 16 flows only from the clamping channel 16 into the rear cylinder chamber 10 with the pressure of the pressurized fluid acting on the front piston 11. Then, the other pair of opposing gripping claws 3b come into contact with the vertical surface of the workpiece W by the movement of the rear piston 12. At this time, since one set of grasping claws 3a, 3a gently clamps the workpiece W, when the other set of grasping claws 3b, 3b contact the workpiece W, the workpiece W is moved in the vertical direction. Centering is performed. When the four gripping claws 3 abut on the workpiece W and centering is performed, the pressure fluid pressure further acts on the front piston 11 and the rear piston 12, and one pair of gripping claws 3a and 3a facing each other. The other pair of opposing gripping claws 3b, 3b are pressed against the workpiece W to clamp the workpiece W. At this time, since the areas of the pressure fluid working surfaces of the front piston 11 and the rear piston 12 are the same, the gripping force acting on the workpiece W is the same, and the workpiece W can be gripped evenly. Becomes even.

Next, when the workpiece W is opened, compressed air supplied from a pressurized fluid supply source (not shown) is supplied to the unclamping cylinder chamber 10 a of the rear cylinder chamber 10 through the unclamping flow path 19. At this time, each clamp side cylinder chamber 9, 10b is open to the atmosphere. Then, the rear piston 12 is moved rearward in the chuck axis direction by the compressed air, the rear drive member 7 is retracted, and the other pair of opposing gripping claws 3b, 3b unclamp the workpiece W. Further, when the rear piston 12 moves backward, the rear surface 15a of the claw engaging portion 15 of the rear drive member 7 comes into contact with the front surface 11c of the front drive member 6 from the state where the workpiece W shown in FIG. 4 is clamped, as shown in FIG. As described above, the rear drive member 7 moves the front drive member 6 backward to move the front piston 11 backward. One set of opposing gripping claws 3a, 3a unclamps the workpiece W by retreating the front drive member 6. As a result, the workpiece is unclamped from the four grasping claws 3. Thus, when the workpiece W is unclamped, a part of the drive member 7 provided on the rear piston 12 is moved by supplying the pressurized fluid to the unclamping cylinder chamber 10a of the rear cylinder chamber 10 and moving the rear piston 12 backward. A part of the front piston 11 is brought into contact and the front piston 11 is moved back together. Thus, the unclamping of the other pair of opposing gripping claws 3b, 3b and the unclamping of the one pair of opposing gripping claws 3a, 3a are performed by the rear piston 12 retreating. This eliminates the need for an unclamping cylinder chamber in the front cylinder chamber 9, thereby reducing the length of the chuck body 2 in the chuck axis direction. Further, since the unclamping cylinder chamber is not required in the front cylinder chamber 9, it is not necessary to enlarge the front piston 11 outward in the chuck radial direction in order to provide a pressure fluid working surface outside the outer peripheral surface of the front drive member 6. The diameter of the chuck 1 can be reduced. Further, since the unclamping cylinder chamber is not provided in each of the front cylinder chamber and the rear cylinder chamber as in the prior art, and no spring is provided for unclamping, the structure of the chuck is simplified.

It is a front view showing a four pawl chuck of the present invention. It is the II-II sectional view taken on the line of FIG. It is a perspective view which shows the outline | summary of a front piston and a rear piston. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows an unclamp state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Four claw chuck 2 Chuck main body 3 Grasp claw 6a Inner diameter part 6 Front drive member 7 Rear drive member 9 Front cylinder chamber 10 Rear cylinder chamber 10a Unclamp side cylinder chamber 10b Clamp side cylinder chamber 11 Front piston 11c Front piston 12 Rear piston 15a Rear surface of rear drive member 16 Clamping channel 19 Unclamping channel W Workpiece

Claims (3)

A front piston and a rear piston are respectively inserted into a front cylinder chamber and a rear cylinder chamber provided in the chuck body, and a front member of the rear piston is inserted into an inner diameter portion of the front piston, and driving members are respectively provided to the front piston and the rear piston. In the four-claw chuck, which is provided and moves two drive gripping claws arranged on the front side of the chuck body by moving each driving member by the movement of the front piston and the rear piston, the chuck body includes the front cylinder chamber and the front cylinder chamber. Clamping channel for supplying pressurized fluid to the clamping cylinder chamber in the rear cylinder chamber and unclamping channel for supplying pressurized fluid to the unclamping cylinder chamber in the rear cylinder chamber are provided for unclamping when the workpiece is unclamped. moving the rear piston rearward by supplying pressure fluid from the flow path, prior to a portion of the driving member provided on the rear piston in contact with the piston Four-jaw chuck, characterized by comprising as move backwards. 2. The four-claw chuck according to claim 1, wherein the driving member is provided on the rear piston so that the rear surface of the driving member can come into contact with the front surface of the front piston. 3. The four-claw chuck according to claim 1, wherein the front piston and the rear piston have the same diameter, and the front piston and the rear piston have the same area of the pressure fluid acting surface.

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