JP2002219605A - Holder and chuck device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holder and a chuck device capable of easily holding an object such as work and a tool having various shape and capable of accurately holding the object. SOLUTION: This chuck device has the holder 10 and a driving cylindrical member 20, in which the holder 10 is inserted. The holder 10 is provided with a support 11, three holding members 12 inserted into the support 11 at a front side in the axial direction of the support 11, and an end plate 13 fitted for fixation to the support 11 at the front side in the axial direction thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gripper and a chuck device, and more particularly to a structure of a gripper suitable for attaching to a main shaft of a machine tool.

[0002]

2. Description of the Related Art In general, various chuck devices are used in a machine tool to attach and fix a work (workpiece) or a tool to the machine. In these chuck devices, for example, a plurality of slits (slits) are formed around an axis in a portion near a tip of a metal cylindrical body, and a tapered (conical surface) inclined on the outer periphery of the tip with respect to the axial direction. Having a tapered (conical) drive surface which is inserted and fitted outside the collet shaft and which is in sliding contact with the driven surface and inclined with respect to the axial direction. A collet chuck provided with a tubular member is known. In this collet chuck, the driving cylinder is further covered by a cylindrical outer cylinder, and a nut member attached to the outer cylinder abuts on the tip of the collet shaft to perform positioning.

In the above collet chuck, when the driving cylinder is moved in the axial direction with respect to the collet shaft, the driving surface moves the driven surface radially inward, and the portion near the tip of the collet shaft moves radially inward. Since it bends, a workpiece, a tool, or the like can be gripped by a gripping surface provided on the inner peripheral surface of the tip end of the collet shaft.

[0004]

However, in the above-mentioned collet chuck, when the shape of a work or a tool is changed, it is necessary to replace the entire collet shaft in accordance with the change, so that the slit is provided as described above. It is necessary to prepare various kinds of expensive collet shafts, and there is a problem that the cost of parts increases.

[0005] Further, the above-mentioned collet shaft is configured so that a workpiece or a tool or the like is gripped on a gripping surface which is an inner peripheral surface thereof by bending a portion near the tip end in a radial direction.
Since the gripping surface will operate so as to grip a workpiece or a tool in a slightly inclined state when viewed in the axial direction,
It is difficult to increase the gripping accuracy of a workpiece or tool, etc. on a gripping object, and the workpiece or tool is likely to be displaced depending on the gripping state between the gripping surface and the gripping object. is there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a gripper which can easily cope with a gripping object having various shapes, and a chuck device having the same. is there. Another object of the present invention is to provide a gripper and a chuck device capable of gripping the gripping object with high accuracy.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a gripping tool according to the present invention is inclined with respect to the axial direction for receiving a driving force by slidingly contacting a driving surface inclined with respect to the axial direction. In a gripper having a driven surface, a support having a plurality of columns protruding in the axial direction and distributed in a circumferential direction around the axis, and having a driven surface, being movable in a radial direction at least within a predetermined range. And a plurality of gripping members are provided, and the gripping members are regulated on both sides in the circumferential direction by the two pillars adjacent in the circumferential direction.

According to the present invention, since the gripping member is only restricted on both sides in the circumferential direction by the support portion of the support, it is possible to cope with a gripping object having a different shape only by replacing the gripping member. Further, since the gripping member can be formed separately from the support, each part can be formed in a simple shape, and the manufacturing cost can be reduced.

Here, the gripping member has an outer gripping type having a gripping surface facing inward in the radial direction and gripping an object to be gripped from the radially outer side, and a gripping surface facing outward in the radial direction. However, a lining type in which the object to be gripped is gripped from the inside in the radial direction can be considered.

In the present invention, it is preferable that the support portion and the gripping member are fitted to each other in the circumferential direction with a margin at least in a radial direction. According to this means, since the support portion and the gripping member are fitted to each other in the circumferential direction, even when configuring a small-diameter chuck device, the support portion and the gripping member can secure their rigidity. It is possible to form a volume, and the gripping accuracy can be improved. Here, on the side face of the gripping member facing in the circumferential direction,
It is desirable to provide a fitting recess for accommodating a part of the support column in the radial direction with a margin. Further, it is desirable that the holding member is configured to be able to be inserted into the support from the front end side of the support portion toward the base side. This makes it easy to fit and remove the gripping member.

[0011] In the present invention, it is preferable to have an urging means for urging the gripping member toward the driving surface. Since the gripping member is urged toward the drive surface by the urging means, the gripping member is separated from the object to be gripped in a state where the driving unit releases the gripping member.

[0012] In the present invention, it is preferable that the urging means is configured to generate an urging force by engaging with the support portion and the gripping member. In this case, the biasing means is constituted by an elastic member fixed to the support, and the center of the elastic member is fixed to the support, and two gripping members having both ends of the elastic member disposed on both sides are elastically pressed. It is desirable to be constituted so that it may be urged. An example of the elastic member is a torsion spring. In this case, the center winding portion of the torsion spring is fixed to the column, and the two gripping members disposed on both sides of the column are both urged by the legs extending from the winding to both sides. Is desirable. In addition, it is desirable that the biasing means is incorporated inside the outer shape of the gripping member and the support portion in order to make the gripping tool compact. For example, a groove may be formed in the gripping member or the support portion, and a biasing unit may be built in the groove.

In the present invention, it is preferable that guide means for guiding the gripping member in a radial direction is provided. Since the gripping member is guided in the radial direction by the guide means, even if there is some backlash between the gripping member and the support portion, the gripping member can be accurately moved in the radial direction. Can be improved. Here, the gripping member has an end face extending in the radial direction (that is, a flat face perpendicular to the axial direction) formed on a side of the both sides in the axial direction where the driven surface is pressed during the gripping operation, and this end face is formed. A guide structure is conceivable which is configured to be slidable in the radial direction with respect to the guide surface of the guide means (also formed of a plane orthogonal to the axial direction).

In the present invention, it is preferable that the guide means is constituted by an end member fixed to a tip of the support portion. The end member has a guiding function in the radial direction of the gripping member and a cover function for closing at least a part of the gap between the gripping members (for example, to prevent chips in a cutting process from entering the gap between adjacent gripping members). Function). Since the end member serving as the guide means is fixed to the tip of the support portion, the conventional outer cylinder is not required, and it is not necessary to attach a nut member to the outer cylinder. Further, the conventional nut member also functions as a guide means for positioning the tip of the collet, but the screwing structure between the outer cylinder and the nut member makes it difficult to increase the surface accuracy of the guide surface of the nut member. On the other hand, the end member fixed to the tip of the support portion of the present invention can provide a guide surface fixed to the support with high precision. Here, the end member may be constituted by a plate-shaped material (end plate) provided with a fixing structure for the support portion and an opening for allowing a grasping object grasped by the grasping member to pass therethrough. desirable.

Further, the chuck device of the present invention is characterized in that a driving portion (for example, a driving cylinder member to be described later) having a driving surface inclined with respect to the axial direction is provided with the driving portion inclined with respect to the axial direction and slidably in contact with the driving surface. And a gripper according to any one of the above-mentioned inventions having a driven surface.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a gripper and a chuck device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing the structure of the chuck device of the present embodiment, and FIG. 2 is a schematic perspective view showing the structure of a gripper (a portion corresponding to a conventional collet shaft) of the present embodiment.

In this embodiment, a gripper 10 shown in FIG.
And a cylindrical driving cylinder 20 into which the gripping tool 10 is inserted. As shown in FIG. 1, a gripper 10 includes a support 11 screwed to a main shaft component 21 such as a machine tool by a screw portion 11 a, and is inserted into the support 11 on the front side in the axis A direction. A plurality of (three in the illustrated example) gripping members 12,
An end plate 13 is attached and fixed to the support body 11 on the front side in the direction of the axis A. Here, on the outer periphery of the gripping member 12, there is provided a conical driven surface 12a inclined to the direction of the axis A so as to face slightly backward.

On the other hand, inside the opening edge of the distal end of the driving cylindrical member 20, a conical driving surface 20a inclined with respect to the direction of the axis A so as to be in sliding contact with the driven surface or slightly forward.
Are formed. The driving member 20 is moved back and forth in the direction of the axis A by a driving mechanism provided in the main shaft of the machine tool, similarly to the above-mentioned conventional collet chuck.

The support 11 is formed in a substantially cylindrical shape as a whole, has the screw portion 11a formed on the outer peripheral surface of the rear end, and has a plurality (3 in the illustrated example) in the circumferential direction around the axis A near the front end. 11A) are formed. At the front end of the support 11, a plurality (three in the illustrated example) of struts 11b distributed in the circumferential direction are formed so as to project forward in the direction of the axis A. Each strut 11b has
An end plate fixing hole 11c penetrating in the direction of the axis A is formed. A spring shaft insertion hole 11d is formed in the direction of the axis A, and the spring shaft 14 is inserted into the spring shaft insertion hole 11d. The spring shaft 14 is fixed by a set screw 15 screwed into a spring shaft fixing hole 11f drilled in the radial direction at the base of the support 11b.

As shown in FIG. 3, the spring shaft 14 is fixed so as to pass through an outer groove 11e formed on the outer periphery near the base of the support 11b. In the outer groove 11e, the spring shaft 14 is fixed by a torsion spring. 16 center winding part 16
a.

The gripping member 12 has the driven surface 12a
And an end surface 12b formed of a smooth surface facing forward in the direction of the axis A.
And a cylindrical gripping surface 12X facing radially inward. Further, as shown in FIG. 2, a pair of fitting recesses 12c provided on both sides in the circumferential direction are formed in the gripping member 12 so as to fit in the circumferential direction with a margin in the radial direction with respect to the support portion 11b. Have been. by this,
One gripping member 12 is fitted to two pillars 11b adjacent in the circumferential direction with a margin in the radial direction. As described above, since the gripping member 12 is restricted in a play-fit state on both sides in the circumferential direction by the two pillar portions 11b fitted on both sides in the circumferential direction, the grip member 12 exceeds the predetermined range corresponding to play in the circumferential direction. It does not move.

Further, the holding member 12 is formed with an arc-shaped spring accommodating groove 12d opened rearward in the direction of the axis A. As shown in FIG. 3, the leg 16b of the torsion spring 16 extends from the outer groove 11e provided in the support 11b into the spring accommodating groove 12d. The leg portion 16b of the torsion spring 16 presses the outer peripheral side surface of the spring accommodating groove 12d radially outward, whereby the gripping member 12 is constantly urged radially outward.

A rear end 12 e of the gripping member 12, which is reduced in diameter and protrudes rearward in the direction of the axis A, is formed at the rear end in the direction of the axis A, and is inserted into the support 11. The rear end 12e is inclined with respect to the direction of the axis A,
A guide inclined surface 12f having a conical surface shape facing rearward in the direction is formed. The guide inclined surface 12f holds the work W when the work W indicated by a dashed line in FIG. 1 is introduced from the rear in the direction of the axis A to the front (in the direction of the arrow in the drawing).
, That is, to the inside of the gripping surface 12X.

The end plate 13 is provided with a work insertion hole 13a formed at the center and a plurality of screw holes 13b formed at positions corresponding to the support portions 11b. The end plate 13 is screwed into the screw hole 13b at the tip of a fixing screw 17 (see FIG. 1) inserted into the end plate fixing hole 11c of the support portion 11b from the rear in the direction of the axis A, whereby the support portion is formed. 11b. The screw hole 13b is a through hole, but may be formed as a closed screw hole on the outer surface side (front in the axial direction) of the end plate 13.

In the present embodiment having the structure described above, when the driving cylinder 20 is moved forward in the direction of the axis A, the driving surface 20a presses the driven surface 12a radially inward, and the gripping member 12 is moved radially inward. Therefore, the workpiece W can be gripped by the gripping surface 12 </ b> X of the gripping member 12. In this case, the gripping member 12 moves in the radial direction with its end surface 12b pressed against the inner surface of the end plate 13 by the pressing action of the drive surface 20a of the drive tubular member 20 and the elastic action of the torsion spring 16. . Therefore, the end surface 12b of the gripping member 12 is accurately guided in the radial direction along the inner surface of the end plate 13, so that the gripping surface 12X can be prevented from hitting the work W halfway. Further, it is possible to improve the gripping accuracy of the workpiece W, that is, to reduce the misalignment of the workpiece W in the gripping state and to reduce the inclination angle of the axis of the workpiece W with respect to the axis A direction.

In the present embodiment, the gripping member 1 is attached to the front end of the support 11 (the portion where the support 11b is formed).
2 can be fitted from the front in the axial direction, and can be removed toward the front in the axial direction. Therefore, the gripping member 12 can be easily exchanged only by loosening the fixing screw 17 and removing the end plate 13. Further, by changing the gripping member 12 to one having a gripping surface 12X having a different position or shape, it is possible to cope with various shapes and dimensions of the work W.

It should be noted that the chuck device of the present invention is not limited to the illustrated example described above, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the gripping member 12 is moved inward in the radial direction by the movement of the driving tubular member 20 forward in the axial direction, and the workpiece W is gripped from the outside. Alternatively, the gripping member may be configured to move radially outward to grip the workpiece from the inside.

The shape of the gripping member can be appropriately designed according to the shape of the work, and the number of gripping members may be any number of 2 or more.

[0029]

As described above, according to the present invention,
It can be easily handled by replacing only the gripping member according to the work shape. In addition, improvement in gripping accuracy by the gripping member can be expected.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the structure of an embodiment of a chuck device according to the present invention.

FIG. 2 is a schematic perspective view showing a structure of a gripping tool in the embodiment.

FIG. 3 is a partial cross-sectional view showing a fitting structure of a support portion and a gripping member in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gripping tool 11 Support body 11b Column part 12 Gripping member 12a Follower surface 12b End surface 12c Fitting concave part 12X Gripping surface 13 End plate 14 Spring shaft 16 Torsion spring 20 Driving cylinder 20a Driving surface

Claims (7)

[Claims] 1. A gripper having a driven surface inclined with respect to the axial direction for receiving a driving force by slidingly contacting a drive surface inclined with respect to the axial direction, wherein the gripper projects in the axial direction and rotates around the axis. A support having a plurality of pillars distributed in the direction, and a plurality of gripping members provided with the driven surface and configured to be movable in a radial direction at least within a predetermined range are provided. A gripper characterized in that it is regulated on both sides in the circumferential direction by two pillars adjacent in the circumferential direction. 2. The gripping tool according to claim 1, wherein the support portion and the gripping member are fitted with each other in the circumferential direction with a margin at least in a radial direction. 3. The gripper according to claim 1, further comprising a biasing unit configured to bias the gripping member toward the driving surface. 4. The gripper according to claim 3, wherein the biasing means is configured to engage with the support portion and the gripping member to generate a biasing force. 5. The gripping tool according to claim 1, further comprising a guide for guiding the gripping member in a radial direction. 6. The gripper according to claim 5, wherein said guide means comprises an end member fixed to a tip of said support portion. 7. The drive unit according to claim 1, further comprising a drive unit having a drive surface inclined with respect to the axial direction, and the driven surface inclined with respect to the axial direction and slidably contacting the drive surface. A chuck device having a gripper.