JP4688048B2 - Chuck device - Google Patents

Description

  The present invention relates to a chuck device mounted on a machine tool for machining a workpiece, and more particularly to a chuck device suitable for gripping a thin workpiece that easily causes chuck deformation.

  When a workpiece is machined by a machine tool such as a grinding machine, the workpiece is gripped by a chuck attached to the spindle of the machine tool. Since the workpieces before machining are usually uneven in the axial direction (thickness), it is necessary to position the end face of the workpiece held by the chuck. Conventionally, with respect to the positioning of the workpiece by this chuck, the workpiece is inserted into the chuck with reference to the pusher of the loader that distributes the workpiece, and clamped with a claw while being pressed against a stopper that is slidable in the axial direction in the chuck. The stopper is urged and positioned in the direction of the workpiece by a spring (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 5-304

  However, there have been the following problems in positioning a workpiece with a conventional chuck.

  Since the chuck pawls are clamped with such a force that the workpiece does not move against the spring force of the stopper, especially when the workpiece is thin, chuck deformation occurs during clamping. On the other hand, if the spring force of the stopper is weakened to prevent chuck deformation, the pressing force of the loader against the pusher becomes insufficient, and the clamp position may vary. Moreover, in a thin workpiece, the stopper does not play the role of regulating the posture of the workpiece, and the workpiece is clamped in a tilted state. Therefore, there is a problem that high-precision processing cannot be performed.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a chuck device capable of accurate positioning even for a thin workpiece that easily causes chuck deformation. .

  In order to achieve the above object, the present invention provides a chuck device mounted on a spindle of a machine tool, which opens and closes in a direction perpendicular to the axis of the spindle, inserts or releases a workpiece when opened, and opens a workpiece when closed. A first chuck mechanism that grips, a slide stopper that is slidably supported in the axial direction of the main shaft, and that urges the workpiece toward the distal end side of the main shaft, and that opens and closes in a direction perpendicular to the axis of the main shaft A second chuck mechanism portion that releases the slide stopper when opened and holds the slide stopper when closed and restricts the sliding motion; the first chuck mechanism portion; and the second chuck mechanism portion; Is applied with a predetermined force to open both chuck mechanism portions, and when the predetermined force is released, the second chuck mechanism portion is preceded by the second chuck mechanism portion. A drive mechanism for driving to close the jack mechanism, characterized by comprising a.

  According to the present invention, in the chuck device having the above-described configuration, the first chuck mechanism and the second chuck mechanism are both elastically deformed by receiving a predetermined pressing force, and a surface of the diaphragm. A diaphragm chuck comprising a plurality of claws provided radially and expanding when the diaphragm is elastically deformed and returning to its original state when the diaphragm is restored.

  According to the present invention, in the chuck device in which the first chuck mechanism section and the second chuck mechanism section are diaphragm chucks, the drive mechanism section is supported slidably in the axial direction of the main shaft, and It is a piston that receives the pressure of compressed air supplied into the main shaft and presses the diaphragm constituting the first chuck mechanism and the diaphragm constituting the second chuck mechanism. To do.

  According to the present invention, in the chuck device in which the drive mechanism portion is constituted by a single piston, the drive mechanism portion includes a spacer that is detachably mounted between the piston and the diaphragm.

  According to the chuck device of the present invention, the following effects can be obtained.

  Before the workpiece is gripped by the first chuck mechanism, the slide stopper is gripped by the second chuck mechanism and the sliding operation is restricted. Therefore, since the spring force does not act in the axial direction of the slide stopper when gripping the workpiece, the clamping force of the workpiece is minimal, and deformation does not occur even when a thin workpiece is gripped. Therefore, accurate positioning is possible and high-precision processing can be performed.

  In addition, since the position close to the workpiece in the slide stopper is gripped by the second chuck mechanism, centering is improved and vibration is suppressed, and the gripping posture of the workpiece is stabilized.

  In addition, since the drive mechanism for opening and closing the first chuck mechanism and the second chuck mechanism can be configured by a single piston, the internal structure of the chuck device is simplified, thereby reducing the manufacturing cost when the design is changed. Is suppressed.

  Further, the opening / closing timing between the first chuck mechanism and the second chuck mechanism can be adjusted by changing the thickness of the spacer mounted between the piston and the diaphragm in the drive mechanism. Therefore, if a chuck mechanism portion and a spacer whose timing is adjusted according to the workpiece are prepared as a set, even if the workpiece changes, it is possible to easily cope with the change by changing the set. Therefore, it is not necessary to perform positioning adjustment every time the workpiece is changed, and the burden on the operator is reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing the main part of a machine tool equipped with the chuck device of the present embodiment, FIG. 2 is a plan view of the chuck device viewed from the front, and FIG. 3 is an operation explanatory view of the chuck device.

  First, the configuration of the chuck device of this embodiment will be described.

  In FIG. 1, in this embodiment, a part of a grinding machine is shown as a machine tool 1 for machining a workpiece, and a chuck device 10 is mounted on a main shaft 2 of the grinding machine. The main shaft 2 of the grinding machine is attached to the inner ring of the ball bearing 3 and is configured to be rotatable around its axis. Therefore, when the main shaft 2 rotates, the chuck device 10 rotates around the axis of the main shaft 2 accordingly. Then, the workpiece W distributed by the loader 4 is rotated while being gripped by the chuck device 10, and a grinding wheel (not shown) is fed to grind the end surface of the workpiece W.

  The chuck device 10 of the present embodiment includes a first chuck mechanism unit 20, a slide stopper 30, a second chuck mechanism unit 40, and a drive mechanism unit 50 described below.

  The first chuck mechanism unit 20 opens and closes in a direction perpendicular to the axis of the main shaft 2 and has a function of inserting or releasing the workpiece W when opened and gripping the workpiece W when closed. The chuck mechanism is a diaphragm chuck including a circular dome-shaped outer diaphragm 21 and a work gripping claw 22 integrated on the surface of the outer diaphragm 21. As shown in FIG. 2, a plurality of workpiece gripping claws 22 are provided on the surface of the outer diaphragm 21 in a radial and equiangular manner (three in this embodiment).

  When the outer diaphragm 21 receives a predetermined pressing force from the inner side, the outer diaphragm 21 is elastically deformed to the outer side, and at the time of the elastic deformation, the three workpiece gripping claws 22, 22,. At this time, the first chuck mechanism 20 is opened, and the workpiece W is inserted or released. On the other hand, when the predetermined pressing force is released, the outer diaphragm 21 is elastically restored, and the three workpiece gripping claws 22, 22,... At this time, the first chuck mechanism unit 20 is closed and the workpiece W is gripped.

  The slide stopper 30 is supported so as to be slidable in the axial direction of the main shaft 2, and has a function of urging the workpiece W toward the distal end side of the main shaft 2. The stopper includes a cylinder 31 fixed to the center of the main shaft 2, a rod 32 slidably supported in the cylinder, and a spring 33 that is fitted to the bottom of the cylinder and presses the rod 32. An air supply path 34 is opened at the bottom of the cylinder, and the air supplied from the supply path is blown from the tip of the rod to the work W through an air passage 35 penetrating the center of the rod. Grinding debris and the like remaining between the two can be removed.

  The second chuck mechanism section 40 has a function of opening and closing in a direction perpendicular to the axis of the main shaft 2, releasing the slide stopper 30 when opened, and holding the slide stopper 30 when closed to restrict its sliding operation. . This chuck mechanism portion is also a diaphragm chuck similar to the first chuck mechanism portion 20 and is composed of a circular dome-shaped inner diaphragm 41 and a stopper gripping claw 42 integrated on the surface of the inner diaphragm 41. . As shown in FIG. 2, a plurality (three in this embodiment) of stopper gripping claws 42 are provided on the surface of the inner diaphragm 41 in a radial and equiangular manner so as not to overlap the workpiece gripping claws 22.

  When the inner diaphragm 41 receives a predetermined pressing force from the inner side, the inner diaphragm 41 is elastically deformed outward, and at the time of the elastic deformation, the three stopper gripping claws 42, 42,... At this time, since the second chuck mechanism section 40 is in an open state, the slide stopper 30 is not restricted and can freely slide in the axial direction. On the other hand, when the predetermined pressing force is released, the inner diaphragm 41 is elastically restored, and the three stopper gripping claws 42, 42,... At this time, the second chuck mechanism section 40 is closed, the position of the slide stopper 30 close to the workpiece W is gripped, and the sliding operation in the axial direction is restricted.

  The drive mechanism unit 50 applies a predetermined force to the first chuck mechanism unit 20 and the second chuck mechanism unit 40 so as to open both chuck mechanism units, and when the predetermined force is released, It has a function of driving the second chuck mechanism unit 40 to be closed before the first chuck mechanism unit 20. This mechanism is an air drive mechanism, and includes a single piston 51 slidably supported in the axial direction of the main shaft 2, and the piston 51 has three large, medium, and small diameter portions (large diameter portion 51a, It is comprised from the diameter part 51b and the small diameter part 51c). As shown in the figure, the large-diameter portion 51a is fitted into the space between the main shaft 2 and the cylinder 31, and the medium-diameter portion 51b is in contact with the thin portion of the inner diaphragm 41 with a removable annular spacer 52 interposed therebetween. The small diameter part 51 c is in direct contact with the thin part of the outer diaphragm 21.

  An air passage 53 for opening the chuck is provided inside the main shaft 2. One end of this passage opens to an air supply pipe in a factory (not shown), and the other end is partitioned by the main shaft 2, the cylinder 31 and the piston 51. The pressurizing chamber 54 is opened. In order to make the pressurizing chamber 54 a sealed space, the main shaft 2 and the piston 51 are sealed by an O-ring 55.

  Therefore, when compressed air is supplied from an air supply pipe in the factory, the compressed air is supplied to the pressurizing chamber 54 through the air passage 53, and becomes a propulsive force that causes the piston 51 to slide forward. When the piston 51 slides forward in response to the propulsive force generated by the compressed air, the thin portion of the outer diaphragm 21 pressed by the small diameter portion 51c is bent and deformed to the outside, and the workpiece gripping claws 22 expand and the first gripping claw 22 expands. The chuck mechanism 20 is opened. At this time, the thin-walled portion of the inner diaphragm 41 pressed by the middle diameter portion 51b is similarly bent outward and the stopper gripping claws 42 are expanded to open the second chuck mechanism portion 40.

  On the other hand, when the supply of compressed air is stopped and released to the atmosphere, the thin portion of the outer diaphragm 21 and the thin portion of the inner diaphragm 41 are both elastically restored and return to their original shape. With this elastic return force, the piston 51 is pushed back to the rear position, and as a result, the first chuck mechanism unit 20 and the second chuck mechanism unit 40 are both closed.

  When closing the chuck mechanism, the second chuck mechanism 40 is closed before the first chuck mechanism 20. The timing is adjusted by changing the thickness of the spacer 52 that is detachably mounted.

  That is, when the thickness of the spacer 52 is decreased, the timing until the two diaphragms completely return to the original shape is shifted by the decrease. That is, when the piston 51 moves forward by being pushed by the compressed air, the timing at which the medium diameter portion 51b starts to push out the inner diaphragm 41 is later than the timing at which the small diameter portion 51c starts to push out the outer diaphragm 21. On the contrary, when the pressing force of the compressed air is released, the timing when the outer diaphragm 21 finishes pushing the small diameter portion 51c back to the original position than the timing when the inner diaphragm 41 finishes pushing the middle diameter portion 51b back to the original position. Is slower. In this way, the second chuck mechanism unit 40 is configured to be closed before the first chuck mechanism unit 20.

  The above is the configuration of the chuck device of the present embodiment. Next, the operation will be described.

  In FIG. 1, when the workpiece W is ground using the grinding machine 1, the workpiece W is gripped by the chuck device 10.

  First, in the chuck device 10, compressed air having a predetermined pressure is supplied into the air passage 53 from an air supply pipe in the factory. Thereby, the compressed air is supplied from the air passage 53 to the pressurizing chamber 54, and a driving force for moving the piston 51 forward is obtained.

  When the piston 51 advances by a predetermined stroke, the two chuck mechanism portions are in the “fully open” state shown in FIG. That is, the thin portion of the outer diaphragm 21 pressed by the small diameter portion 51c bends and deforms outward, and accordingly, the workpiece gripping claws 22 expand and the first chuck mechanism portion 20 opens. At this time, the thin portion of the inner diaphragm 41 pressed by the middle diameter portion 51b is similarly bent outward and the stopper gripping claws 42 are expanded to open the second chuck mechanism portion 40.

  As described above, in a state where the first chuck mechanism unit 20 and the second chuck mechanism unit 40 are both opened, the loader 4 is moved forward to distribute the work W held by the pusher 5. Here, the length dimension of the positioning member 6 is set in advance according to the thickness dimension of the workpiece W. When the workpiece W held by the pusher 5 is abutted against the rod tip of the slide stopper 30, the workpiece W is urged forward by the rod 32 by the spring force of the spring 33. Thus, accurate positioning in the axial direction can be performed with the tip surface of the positioning member 6 as a reference surface.

  Next, the supply of compressed air from the air supply pipe is stopped with the workpiece W positioned in the axial direction. As a result, the compressed air in the pressurizing chamber 54 is released to the atmosphere, and the propulsive force that moves the piston 51 forward is lost.

  When the driving force for advancing the piston 51 is lost, the thin portion of the outer diaphragm 21 and the thin portion of the inner diaphragm 41 that have been elastically deformed return to their original shape by their own elastic force. The piston 51 in contact with both diaphragms is pushed back by this elastic return force, and as a result, both the first chuck mechanism 20 and the second chuck mechanism 40 are closed. Here, the operation timing of the first chuck mechanism section 20 and the second chuck mechanism section 40 is as follows.

  First, in a state where the piston 51 is retracted to the vicinity of the intermediate position, the two chuck mechanism portions are in the “half-open” state shown in FIG. That is, as described above, the timing until the inner diaphragm 41 completely returns to the original shape is faster than the timing until the outer diaphragm 21 completely returns to the original shape. For this reason, the stopper gripping claws 42 of the second chuck mechanism portion 40 are closed earlier than the workpiece gripping claws 22 of the first chuck mechanism portion 20 to clamp the slide stopper 30, so the axial direction of the slide stopper 30 The sliding motion to is regulated.

  When the piston 51 finally moves back to the original reference position, the two chuck mechanism portions are in the “fully closed” state shown in FIG. That is, the outer diaphragm 21 completely returns to its original shape, the work gripping claws 22 are closed, and the work W is clamped. At this time, the slide stopper 30 is clamped by the stopper gripping claws 42 as described above, and the spring force of the spring 33 does not act in the axial direction of the slide stopper 30, so the clamping force of the workpiece W is offset to cancel this spring force. There is no need to set a large value. Therefore, the workpiece W can be gripped with a soft clamping force.

  Finally, with the workpiece W gripped, the loader 4 is moved backward to remove the pusher 5 from the workpiece W, and the loader 4 is turned in the opposite direction. As a result, the grinding surface of the workpiece W appears. Therefore, the chuck device 10 is rotated around the axis of the main shaft 2 and a grinding wheel (not shown) is fed to grind the grinding surface of the workpiece W.

  As described above, according to the chuck device 10 of the present embodiment, when the workpiece W is gripped, the second chuck mechanism unit 40 is closed before the first chuck mechanism unit 20 and the slide stopper 30 moves in advance. Is to regulate. For this reason, the clamping force of the workpiece W can be minimized, and even when the workpiece W is thin, the workpiece W can be gripped with a soft clamping force, and deformation at the time of clamping can be prevented. . In addition, since the slide stopper 30 is gripped at a position close to the workpiece W, there is an effect that centering is improved and vibration is suppressed and the gripping posture of the workpiece W is stabilized.

  Furthermore, since the drive mechanism 50 that opens and closes the first chuck mechanism 20 and the second chuck mechanism 40 is constituted by a single piston 51, the internal structure of the chuck device 10 is not complicated. In addition, there is no cost increase when the design is changed. In addition, by appropriately changing the thickness of the spacer 52 that is detachably mounted between the piston 51 and the inner diaphragm 41 in the drive mechanism 50, the first chuck mechanism 20 and the second chuck mechanism 40 The opening and closing timing can be adjusted. Therefore, if the chuck mechanism and the spacer 52 whose timing is adjusted in accordance with the workpiece W are prepared as a set, even if the type or processing location of the workpiece W changes, it is possible to easily cope with the change of the set. Can do.

Sectional drawing which shows the principal part of the machine tool carrying the chuck device of this embodiment. The top view which looked at the chuck | zipper apparatus of FIG. 1 from the front. Operation | movement explanatory drawing of the chuck apparatus of FIG.

Explanation of symbols

W Work 1 Machine tool (grinding machine)
2 Main shaft 3 Ball bearing 4 Loader 5 Pusher 6 Positioning member 10 Chuck device 20 First chuck mechanism 21 Outer diaphragm 22 Work gripping claw 30 Slide stopper 31 Cylinder 32 Rod 33 Spring 34 Air supply path 35 Air path 40 Second chuck Mechanism part 41 Inner diaphragm 42 Stopper gripping claw 50 Drive mechanism part 51 Piston 52 Spacer 53 Air passage 54 Pressurizing chamber 55 O-ring

Claims (4)

A chuck device mounted on a spindle of a machine tool,
A first chuck mechanism that opens and closes in a direction perpendicular to the axis of the main shaft, inserts or releases the workpiece when opened, and grips the workpiece when closed;
A slide stopper supported so as to be slidable in the axial direction of the spindle, and biasing the workpiece toward the tip side of the spindle;
A second chuck mechanism that opens and closes in a direction perpendicular to the axis of the main shaft, releases the slide stopper when opened, holds the slide stopper when closed, and restricts the sliding movement;
The first chuck mechanism is driven when a predetermined force is applied to the first chuck mechanism and the second chuck mechanism to open both chuck mechanisms and the predetermined force is released. And a drive mechanism unit that drives the second chuck mechanism unit to close the second chuck mechanism unit before the unit. Both the first chuck mechanism and the second chuck mechanism are
A diaphragm that is elastically deformed under a predetermined pressing force;
2. The chuck according to claim 1, wherein the chuck comprises a plurality of claws radially provided on the surface of the diaphragm and expanding when the diaphragm is elastically deformed and returning to its original state when the diaphragm is elastically restored. 3. apparatus. The drive mechanism is
The diaphragm constituting the first chuck mechanism and the second chuck mechanism are configured to be supported slidably in the axial direction of the spindle and receiving the pressure of compressed air supplied into the spindle. The chuck device according to claim 2, wherein the chuck device is a single piston that presses against the diaphragm. The drive mechanism is
The chuck device according to claim 3, further comprising a spacer detachably mounted between the piston and the diaphragm.

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