JP2005125429A - Chuck device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chuck device by which workpieces with different diameters can be chucked by a simple structure. <P>SOLUTION: A fitting hole 23 of an extension pin 22 is integrated by fitting it tightly to the tip of a clamp pin 21a of a chuck body 30 mounted to a main spindle of a lathe. The extension pin 22 is positioned concentrically with a pin axial center of the clamp pin by fitting the inner periphery of its fitting hole 23 while being in contact with the whole periphery of the peripheral face of the clamp pin 21a. When the end face of the clamp pin 21a reaches and abuts against the bottom face of the fitting hole 23, the extension pin 22 is not radially moved any more and surely positioned radially. Therefore, the positioning and the mounting of the extension pin 22 are facilitated. The joining part is stabilized. As a result, dimensional errors when the workpiece W is clamped hardly occur. Also, a ball of a ball plunger, which is provided protrusively in the fitting hole, is fitted to a groove 29 provided to the peripheral face of the clamp pin 21a in the positioned state. Consequently, the falling-off of the extension pin 22 can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a clamp pin of a chuck device for chucking a workpiece during lathe processing or the like.

  The conventional chuck device that clamps thin and fragile workpieces is to arrange a large number of cylinders around the axis of the chuck body and operate the piston rod of the cylinders so as not to deform the target workpiece. Thus, the pin interlocked with the piston rod is advanced toward the workpiece, and the workpiece is clamped while the force is distributed at a number of supporting points along the outer peripheral surface or inner peripheral surface of the workpiece. .

  For example, referring to FIG. 6 which is an embodiment of the present invention, a plurality of cylinders 20 facing radially from the axis c are provided on the chuck body 30 concentrically fixed to the axis c of the main spindle of the lathe. Provide at equal positions around the axis. One end of the piston rod 21 of the cylinder 20 is used as a clamp pin 21a, and the pin 21a can protrude inward from the inner peripheral surface of the cylindrical hole 33 in the front portion of the chuck body 30 where the workpiece W is disposed. It has become.

  The inner cylinder chamber 20a and the outer cylinder chamber 20b of the cylinder 20 communicate with separate fluid supply means (not shown) via fluid circuits 32a and 32b, respectively, and in the cylinder chambers 20a and 20b, respectively. The working fluid can be supplied and discharged.

  Each clamp pin 21a composed of the piston rod 21 retreats outward in the radial direction of the shaft center c by pressurization by supplying a working fluid to the inner cylinder chamber 20a. Place and release the pressure. Next, by supplying and pressurizing the working fluid to the outer cylinder chamber 20b, each clamp pin 21a advances to the inside in the radial direction and clamps the workpiece W.

  However, the stroke range of the piston rod 21 of the cylinder 20 of this chuck device is a limited range shown by a solid line to a chain line in FIG. 6, and chucks a workpiece W having a diameter exceeding the stroke range. I can't.

  For this reason, in order to cope with the workpiece W having a diameter exceeding the stroke, it is necessary to replace the piston rod 21 with an object having a different length each time or to increase the stroke of the piston rod of the cylinder.

  However, when exchanging the piston rod 21 with a different length, it is necessary to extract the pin 21a and the piston rod 21 from the cylinder 20, and the replacement involves the discharge of the pressure fluid. It is complicated. In addition, repeated attachment / detachment of the clamp pin 21a and the piston rod 21 is liable to cause wear and damage of the parts, and is not preferable for maintaining the accuracy of centering. Further, it is not preferable to lengthen the stroke of the piston rod 21 of the cylinder 20 because a difference in advance and retreat is likely to occur in each clamp pin 21a, and the accuracy of clamping the workpiece W evenly over the entire circumference decreases.

  Therefore, for example, there is a chuck device shown in FIG. 7 in which a detachable extension member is attached to the tip of the clamp pin without changing the stroke so that it can cope with the workpiece W having a different diameter.

  As shown in FIG. 7B, the clamp pin 11a of the chuck body 1 of this apparatus has an inverted T-shaped configuration in which the cross section perpendicular to the pin axis is widened to a stepped shape at the tip of the pin. The extension member 12 connected to the pin 11a has a cylindrical shape with the same outer diameter as that of the clamp pin 11a. At the end portion on the pin 11a side, a T-shaped opening opens on both sides of the column circumferential surface and the end surface side. A groove 12a is provided.

  As shown by an arrow in FIG. 7B, the clamp pin 11a is inserted into the opening of the peripheral surface of the T-shaped groove 12a, and the extension member 12 is inserted into the clamp pin 11a along the T-shaped groove in the main axis direction. The pin 11a is fitted and connected to the T-shaped groove 12a. By this connection, the stepped portion at the tip of the pin 11a having an inverted T-shape is fitted into the stepped portion at the bottom of the T-shaped groove 12a, so that the extension member 12 does not come off in the axial direction.

  Further, when the extension member 12 is connected, as shown in FIG. 7A, the auxiliary ring 6 that can be fitted along the inner peripheral surface of the hole 3 of the chuck body 1 in which the workpiece W is disposed. Is used. The auxiliary ring 6 is provided with a through-hole 5 concentric with the axial center of the piston rod 11 through which the clamp pin 11a of the pinstone rod 11 and the extension member 12 pass. By sliding in, the rod 11 does not move except in the axial direction of the rod 11. For this reason, the extending member 12 is restrained in the main axis direction indicated by the arrow in FIG. 7A and the direction around the axis c of the main axis, so that the radius of the extension member 12 can be ensured without deviation from the axis of the piston rod 11. It can move forward and backward in the direction and keep the accuracy of the clamp.

  Further, the extension member 12 is provided with a pin hole 12 b leading to the through hole 5, and the pin 8 of the mounting jig 7 is inserted into the pin hole 12 b of the extension member 12 inserted into the through hole 5. The extension member 12 is positioned in the radial direction. By this positioning, the radial positions of the respective clamp pins 11a and the T-shaped grooves 12a of the extension member 12 coincide with each other, so that they can be easily fitted together. Further, a locking bolt 9 is screwed into the auxiliary ring 6, and the tip of the bolt 9 is fitted into a groove 12c in the pin axis direction provided in the extension member 12, so that the extension member 12 does not rotate around the pin axis. To do. This detent prevents the T-shaped groove 12a from moving in the direction of the main axis, and its peripheral opening always faces in the direction of the pin 11a so that the pin 11a can be easily inserted (for example, patents). Reference 1).

In the chuck device shown in FIG. 7, a spring S is arranged in the inner cylinder chamber instead of the action of the fluid circuit 32a in FIG. In a normal state where no pressure is applied from the fluid circuit 2, the clamp pin 11 a is retracted radially outward by the urging force of the spring S.
JP-A-10-249614

  In the chuck device shown in FIG. 7, when the extension member 12 is attached to and detached from the piston rod 11, the extension member 12 is positioned in the radial direction and the position around the axis, and the extension member 12 is used as the axis of the piston rod 11. An auxiliary ring 6 is required to advance and retract along. For this reason, there is a problem that the number of parts constituting the chuck device increases, and the time required for attaching and detaching these parts increases.

  Accordingly, an object of the present invention is to make it possible to easily chuck workpieces having different diameters with a simpler structure.

  In order to solve the above-described problems, the present invention is configured such that the extension pin is fitted into the tip of the clamp pin so as to be integrated so that the extension pin is not dropped by the ball plunger. In this way, the extension pin can be easily connected to the clamp pin, both can be firmly fixed, and the structure for preventing the drop-off is also simple.

  Specifically, the chuck body attached to the main spindle of the lathe is provided with a plurality of cylinders facing radially from the axis, and each cylinder can be supplied and discharged with working fluid. It is an extension pin that is attached to the tip of a clamp pin of a chuck device that clamps a workpiece by advancing and retracting a clamp pin made of a piston rod in the radial direction and pressing the outer peripheral surface or inner peripheral surface of the workpiece with each pin.

  The extension pin has a fitting hole fitted in contact with the peripheral surface and end face of the clamp pin, and a ball plunger protruding into the fitting hole is provided. By fitting the tip of the clamp pin in the fitting hole, the peripheral surface of the clamp pin presses the ball at the tip of the ball plunger toward the inner periphery of the fitting hole, and the end surface of the clamp pin contacts the bottom surface of the fitting hole. When contacted, the ball fits into a groove provided on the peripheral surface of the clamp pin.

  When the extension pin is fitted to the tip of the clamp pin, the extension pin is fitted while the inner circumference of the fitting hole is in contact with the peripheral surface of the clamp pin, so the extension pin is surely concentric with the pin axis of the clamp pin. Is positioned. Further, when the end face of the clamp pin reaches the bottom surface of the fitting hole, the extension pin is prevented from moving further in the radial direction, so that the extension pin is reliably positioned in the radial direction. For this reason, the extension pin can be easily positioned and attached, and the extension pin is firmly held by the peripheral surface and end face of the clamp pin, the joint is stabilized, and the dimensional error of the joint is less likely to occur.

  Further, in the process of fitting the extension pin, the ball plunger ball provided protruding from the inner peripheral surface of the fitting hole is pressed against the peripheral surface of the clamp pin and retreats toward the inner peripheral surface of the temporary fitting hole. In a state where the extension pin is completely fitted and positioned, the ball plunger ball fits into a groove provided on the circumferential surface of the clamp pin and protrudes again into the fitting hole. For this reason, the extension pin is fixed to the clamp pin through the groove and the ball plunger so as not to fall off, and the fixing is automatically performed when the extension pin is completely fitted to a predetermined position. So easy.

  Further, in the above configuration, if the cross-section perpendicular to the pin axis of the clamp pin is circular and the groove is provided on the entire circumference of the clamp pin, the ball plunger of the extension pin can be used regardless of the direction around the pin axis. Since it always fits in the groove of the clamp pin, it is possible to shorten the time required to confirm the direction of the pin when attaching the extension pin.

  In the present invention, since the tip position of the clamp pin can be changed with a simple structure using the extension pin, it is possible to chuck workpieces having different diameters, and the extension pin can be easily attached and detached.

  FIG. 1 to FIG. 6 show an embodiment, and the chuck device of this embodiment is shown in FIGS. 2 and 3, in front of a chuck body 30 fixed concentrically to the axis c of the main spindle of the lathe. A large number of cylinders 20 are arranged along the inner peripheral surface of a cylindrical hole 33 provided in the center in the direction of the axis c so as to be equally divided around the axis c.

  As shown in FIG. 1, one end of the piston rod 21 of the cylinder 20 is used as a clamp pin 21 a, and the pin 21 a extends from the inner peripheral surface of the cylindrical hole 33 in the front portion of the chuck body 30 where the workpiece W is disposed. It can appear inward.

  The cylinder 20 is provided with an inner cylinder chamber 20a and an outer cylinder chamber 20b with the piston portion of the piston rod 21 interposed therebetween. Both cylinder chambers 20a and 20b are not shown through fluid circuits 32a and 32b, respectively. The working fluid can be supplied to and discharged from the cylinder chambers 20a and 20b in communication with separate fluid supply means.

  Each clamp pin 21a formed of the piston rod 21 is configured to retreat outwardly in the radial direction of the axis c indicated by an arrow A in FIG. 6 by pressurization by supplying a working fluid to the inner cylinder chamber 20a. By supplying and pressurizing the working fluid to the outer cylinder chamber 20b, each clamp pin 21a advances inward in the radial direction, which is the opposite direction of the arrow A in FIG.

  The piston rod 21 and the clamp pin 21a provided at the tip of the piston rod 21 have an integral cylindrical shape, and a groove 29 is provided on the entire circumference of the clamp pin 21a. Further, a grip portion 27 made of a cemented carbide for holding the workpiece W so as not to slip is provided on the end face of the clamp pin 21a.

  As shown in FIG. 4, the extension pin 22 has a fitting hole 23 that fits in contact with the peripheral surface and end face of the clamp pin 21a, and a ball plunger 26 from which the ball 26a projects is provided in the fitting hole 23. It has been. The ball plunger 26 is built in the bolt 25, and the bolt 25 is screwed into the extension pin 22 and fixed.

  By fitting the tip of the clamp pin 21 a into the fitting hole 23, the clamp pin 21 a peripheral surface retreats into the plunger 26 by pressing the ball 26 a at the tip of the ball plunger 26 toward the inner peripheral surface of the fitting hole 23. At the same time, when the end surface of the clamp pin 21a contacts the bottom surface 23a of the fitting hole 23, the ball 26a protrudes into the fitting hole 23 so as to fit into a groove 29 provided on the peripheral surface of the clamp pin 21a. Therefore, the extension pin 22 is prevented from falling off from the clamp pin 21a. Further, the fixation by the ball plunger is simple because the ball 26a automatically protrudes into the groove 29 when the extension pin 22 is completely fitted to a predetermined position in the fitting hole 23. .

  At the time of this fitting, as shown in FIG. 5, since the recess 23c is provided in the bottom surface 23a of the fitting hole 23, the grip portion 27 protruding from the end face of the clamp pin 21a interferes with the bottom surface 23a. Instead, the end surface portion other than the grip portion 27 on the end surface of the clamp pin 21a comes into contact with the bottom surface 23a to position the extension pin 22 in the radial direction. For this reason, the shape of the grip portion 27 on the end face of the clamp pin 21a does not affect the positioning and fixing when the extension pin 22 is connected.

  Further, when the extension pin 22 is fitted to the tip of the clamp pin 21a, the extension pin 22 is fitted while the peripheral surface 23b of the fitting hole 23 is in contact with the peripheral surface of the clamp pin over the entire circumference. 22 is positioned securely and concentrically with the pin shaft center of the clamp pin 21a, and fits snugly while sliding in contact with the entire circumference, so that rattling after connection is less likely to occur. Further, when the end face of the clamp pin 21a reaches the fitting hole bottom face 23a, the extension pin is prevented from moving further in the radial direction. In addition, the radial dimension error around the axis c of the grip portion 27 is less likely to occur.

  Hereinafter, the operation of the chuck device in which the extension pin 22 is attached to the clamp pin 21a will be described. When the workpiece W is chucked, as shown in FIG. 1, first, the hydraulic pressure of the fluid circuit 32b is released and the fluid circuit 32a is released. By supplying the working fluid to, each piston rod 21 is retracted radially outward (state shown in FIG. 1).

  In this state, the workpiece W is inserted into the hole 33 from the front surface of the chuck body 30, and the workpiece W (not shown) is temporarily placed in contact with the support surface 34 in the hole 33. Next, by releasing the hydraulic pressure of the fluid circuit 32a and supplying the working fluid to the fluid circuit 32b, each piston rod 21 is advanced inward in the radial direction, and the clamp pin 21a and the extension pin 22 are directed inward in the radial direction. The workpiece W is clamped from the outer circumference equally divided position by the grip portion 27 fitted to the tip of the extension pin 22. The gripping portion 27 provided on the extension pin 22 is the same as the gripping portion provided on the end face of the clamp pin 21 a, and is fitted into the hole at the tip of the extension pin 22 and fixed with a stopper 28.

  When this extension pin is not used, the chuck device can be used in the mode shown in FIG. 6, and from the tip position (the gripping portion 27 position) of the extension pin 22 shown in FIG. By preparing various extension pins 22 having different distances to the bottom surface 23a, it is possible to select and use the extension pins 22 that match the diameter of the workpiece W to be clamped.

  In this embodiment, the inner peripheral surface of the fitting hole 23 of the extension pin 22 and the outer peripheral surface of the clamp pin 21a are in slidable contact over the entire periphery, but are not limited to this embodiment. As long as the cross sections can be fixed so that they do not fit and move, the mutual surfaces may be in contact with each other rather than in contact with the entire circumference. Moreover, although it is desirable to provide two ball plungers 26 facing each other in the fitting hole 23 as in this embodiment, the number is not particularly limited. The form of the holding part 27 is also free.

Cross-sectional view of one embodiment Perspective view of the same embodiment Plan view of the same embodiment The details of the extension pin are shown, (a) is a perspective view, (b) is a front view, (c) is a right side view, and (d) is a cut front view. Explanatory drawing showing the mounting state of the extension pin Sectional drawing which shows the state which removed the extension pin of FIG. Cross section of conventional example

Explanation of symbols

1,30 Chuck body 2, 32a, 32b Fluid circuit 3, 33 Hole 10, 20 Cylinder 11, 21 Piston rod 11a, 21a Clamp pin 12 Extension member 22 Extension pin 23 Fitting hole 24 Nut 25 Bolt 26 Ball plunger 26a Ball 27 Grip 28 Retaining 29 Groove

Claims (2)

A chuck main body 30 attached to the main shaft of the lathe is provided with a plurality of cylinders 20 that are directed in the radial direction from the axis, and each cylinder 20 can be supplied and discharged with a working fluid. In the chuck device that clamps the work W by moving the clamp pin 21a composed of the piston rod 21 back and forth in the radial direction and pressing the outer peripheral surface or the inner peripheral surface of the work W by each pin 21a,
An extension pin 22 is attached to the tip of the clamp pin 21a, and the extension pin 22 has a fitting hole 23 that fits in contact with the peripheral surface and end face of the clamp pin 21a, and a ball plunger that protrudes into the fitting hole 23. 26 is provided,
When the extension pin 22 is fitted to the tip of the clamp pin 21a through the fitting hole 23 and the end surface of the clamp pin 21a is in contact with the bottom surface of the fitting hole 23, the ball 26a of the ball plunger 26 is moved to the clamp pin 21a. A chuck device that fits into a groove 29 on the peripheral surface.   2. The chuck device according to claim 1, wherein the clamp pin 21 a has a circular cross-section perpendicular to the pin axis, and the groove 29 is provided on the entire circumference of the clamp pin 21 a.

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