JP2007125668A - Collet chuck device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collet chuck device capable of use in clamping a plurality of workpieces having different clamping diameters and suitably shortening resetting time. <P>SOLUTION: An axial position of one of a plurality of holding parts 11 and 12 is arranged at a center position of an axial width of a contact tapered surface 10B of a collet sleeve 8 and a collet 10 or adjacently to the center position. At least one of the other holding part 12 is arranged on a distal end side of the collet 10 of the center position of the axial width of the contact tapered surface 10B. At the time of clamping by the holding part 12 arranged on a distal end side of the collet 10, the workpiece W2 is clamped by the holding part 12 arranged on the distal end side of the collet 10, while making the holding part 11 arranged at the center position of the axial width of the contact tapered surface 10B or adjacently to the center position hold a member 15 provided with a diameter corresponding to the diameter of the workpiece held by the holding part 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a collet chuck device that is provided at a spindle end portion of a machine tool represented by a cam grinder and clamps the shaft end of a workpiece, and particularly to selectively clamp two types of workpieces having different clamp diameters. The present invention relates to a suitable collet chuck device.

  In conventional collet chuck devices that clamp the shaft end of a workpiece (workpiece), the setup change time is shortened when the diameter of the clamped part of the workpiece or the position and diameter of the phase reference pin changes with the change of the workpiece. A collet chuck device has been proposed (see Patent Document 1).

This is because a plurality of types of auxiliary collets having different inner diameters corresponding to the workpiece are prepared according to the common outer diameter corresponding to the main collet and the type of workpiece, and the auxiliary collet selected according to the type of workpiece. Is inserted into the main collet to clamp the workpiece, and only the auxiliary collet is replaced when changing the setup.
Japanese Patent Laid-Open No. 9-123055

  However, in the above conventional example, when the diameter of the clamped part of the workpiece or the position and diameter of the phase reference pin changes, it is possible to replace the auxiliary collet that directly clamps the workpiece according to the operation of the main collet. is doing. In general, the collet is a component that affects the runout accuracy when clamping the workpiece. Therefore, in the method of replacing the auxiliary collet as in the conventional example, there is a concern that the runout accuracy may deteriorate due to the replacement of the auxiliary collet. After the replacement, it is necessary to check and adjust the runout accuracy, which increases the downtime of the equipment. In addition, the collet needs to be disassembled and assembled, and the downtime of equipment for setup change also increases.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a collet chuck device that can be used for a plurality of work clamps having different clamp diameters and is suitable for shortening the time required for setup change.

  The present invention provides a gripping portion that makes contact between a collet sleeve arranged on the back surface and a tapered surface, and clamps a columnar or cylindrical workpiece from the outer peripheral side or the inner peripheral side by axial relative movement with the collet sleeve. In the collet chuck device comprising a collet that is arranged with a plurality offset in the axial direction corresponding to at least two clamp diameters, the axial position of one of the plurality of gripping portions is set between the collet sleeve and the collet. A central position of the axial width of the contact tapered surface or a position close to the central position, and at least one of the other gripping portions is disposed closer to the collet tip than the central position of the axial width of the contact tapered surface, At the time of clamping by the grip part arranged on the tip side of the collet, the axial position of the contact taper surface is in the center position or close to the center position The grip portion was placed in, while grasping the member having a diameter corresponding to the workpiece diameter for clamping in the gripper, and so as to clamp the workpiece by the holding portion disposed on the collet distal end side.

  Therefore, in the present invention, when the workpiece is clamped by the gripping portion arranged at the central position or close to the central position, the axial positions of the clamping force received from the contact taper surface and the clamping reaction force received from the workpiece coincide with each other. Alternatively, it is possible to avoid or reduce the couple of forces generated in the collet that are close to each other. On the other hand, when the workpiece is clamped by the grip portion on the tip side, it corresponds to the workpiece diameter clamped by the grip portion on the grip portion on the center position side. Since the workpiece is clamped by the grip portion on the distal end side while the member having the diameter to be gripped, the amount of deformation of the collet can be limited and the collet can be prevented from being damaged.

  Hereinafter, an embodiment of a collet chuck device of the present invention will be described with reference to FIGS.

  FIG. 1 is a configuration diagram showing a first embodiment of a collet chuck device to which the present invention is applied.

  In FIG. 1, a collet chuck device 1 is attached to an end face of a main shaft 2 via a rotating face plate 3, a connecting face plate 4 attached to an end face of the rotating face plate 3 opposite to the main shaft 2, and a connecting face plate 4. A cylindrical member 5 fixed to the end surface on the opposite side of the rotating face plate 3; a piston 7 slidably fitted to an inner peripheral surface of a cylinder 6 formed by the cylindrical member 5; A piston sleeve 7A slidably fitted to the inner peripheral surface of the cylindrical portion 4A and the cylindrical member 5 of the connecting face plate 4 and a collet sleeve 8 fixed to the open end of the piston sleeve 7A are provided. Cylinder chambers 6A and 6B are formed on both sides of the piston 7, and a working fluid is selectively supplied to each of the pistons. One cylinder chamber 6A operates in a direction in which the collet sleeve 8 is pushed out, and the other cylinder chamber 6B has a collet. The sleeve 8 is operated in the retracting direction.

  Further, the collet chuck device 1 is provided with a holding ring 9 fixed to the connecting face plate 4 slidably on the inner peripheral surface of the piston sleeve 7A, and the holding ring 9 has a base of the collet 10 fixed thereto. The collet 10 includes a chuck portion 10A formed by a plurality of radial slits. The outer periphery of the chuck portion 10A is formed as a tapered surface 10B, and a tapered inner peripheral surface 8B provided on the collet sleeve 8 and a tapered surface. They are in contact with each other. Further, on the inner peripheral side of the holding ring 9, a convex portion 4 </ b> B that protrudes from the connecting face plate 4 is provided.

  When the collet sleeve 8 is pushed out by the operation of the piston 7, the chuck portion 10A of the collet 10 increases the diameter by contacting the tapered surfaces 10B and 10B and releases the clamp of the work W arranged on the inner peripheral side. When the collet sleeve 8 is retracted, the collet sleeve 8 is operated to clamp the work W disposed on the inner peripheral side by reducing the diameter by the contact of the tapered surfaces 8B and 10B. The collet chuck device having the above-described structure is generally known.

  The collet chuck device 1 according to the present embodiment has a large-diameter gripping portion 12 and a small-diameter gripping portion 11 that are engaged with the outer periphery of the workpiece of the chuck portion 10A in order to enable a plurality of workpiece clamps having different clamp diameters. It consists of two stages. And when clamping the small diameter workpiece | work W1, as shown in FIG. 2, the outer periphery of the workpiece | work W1 is clamped by the small diameter holding part 11. As shown in FIG. The small-diameter gripping portions 11 are arranged so as to be positioned approximately at the center in the axial direction of the outer peripheral tapered surface 10B of the collet 10.

  Further, when clamping the large-diameter workpiece W2, as shown in FIG. 3, the large-diameter gripping portion 12 arranged so as to be positioned forward from the axial center of the outer peripheral tapered surface 10B of the collet 10 is used. The outer periphery of the workpiece W2 is clamped. In this case, the chuck portion 10A of the collet 10 is simultaneously used as a dummy that has the same outer diameter as the clamp target to be clamped by the small diameter gripping portion 11 but is different from the workpiece W. The shaft 15A of the angle reference / longitudinal block 15 described later is also gripped.

  Further, the collet chuck device 1 according to the present embodiment fixes the angle reference / longitudinal blocks 14 and 15 to the tips of the convex portions 4B of the connecting face plate 4 as positioning members in the axial direction and the rotational direction of the workpiece W. Prepare. The angle reference / longitudinal blocks 14 and 15 have different grinding dimensions depending on an angle with respect to a preset reference angle. For example, the angle position of the workpiece W is set during cam grinding, and the convex portion 4B. On the other hand, the pin 16 prevents rotation and the center pin 17 determines the center position and fixes it.

  That is, the contact portion of the angle reference / longitudinal blocks 14 and 15 that contacts the work W is provided with a reference pin W3 provided at the end of the work W or an engagement groove 20 that engages with a reference angle groove. The reference angle of the workpiece W is set by the engagement between the joint groove 20 and the reference pin W3 on the workpiece W side or the reference angle groove. The angle reference / longitudinal blocks 14 and 15 set the axial position of the workpiece W according to the axial position of the abutting portion that abuts the workpiece W.

  In addition, the angle reference / longitudinal blocks 14 and 15 correspond to a plurality of workpieces W1 and W2 having different clamp diameters, and as shown in FIG. The block 14 is attached to the convex portion 4B. Further, as shown in FIG. 3, for a large-diameter workpiece W2, a shaft portion 15A having an outer diameter equivalent to the outer diameter of the small-diameter workpiece W1 clamped by the small-diameter gripping portion 11 and the tip of the shaft portion 15A An engagement groove that is configured by a diameter-enlarged portion 15B that is enlarged near the outer diameter of the large-diameter workpiece W2 to be clamped on the side, and that engages with a reference pin W3 or a reference angle groove provided at the end of the workpiece W2 on the tip surface A large-diameter angle reference / longitudinal block 15 having 20 is mounted on the convex portion 4B.

  The clamping operation of the small-diameter workpiece W1 and the large-diameter workpiece W2 by the collet chuck device 1 having the above configuration will be described below. 4 and 6 are general views including the camshaft which is the workpiece W and the collet chuck device 1. FIG. 4 shows a clamped state of the small-diameter workpiece W1, and FIG. 6 shows a clamped state of the large-diameter workpiece W2. FIG. 5 shows the procedure of the camshaft clamping operation by the collet chuck device 1. First, the clamping operation of the small-diameter workpiece W1 will be described.

  First, hydraulic pressure is introduced into the cylinder chamber 6A, the collet sleeve 8 is pushed out by the piston 7 and the piston sleeve 7A, and the chuck portion 10A of the collet 10 is opened. Then, as shown in FIG. 1, a small diameter angle reference / longitudinal block 14 is attached to the tip of the convex portion 4 </ b> B of the collet chuck device 1.

  Then, as shown in FIG. 4, a small-diameter camshaft W1, which is a workpiece, is carried onto the work rest WR (S1), and the phase reference pin W3 press-fitted into the end of the small-diameter camshaft W1 is an angle reference. The rear end stopper ST is advanced until it comes into contact with the cum long block 14 (S2), and is further pressed. Next, the work rest WR is clamped at a low pressure, and the main shaft 2 is rotated (S3). The main shaft 2 and the angle reference / longitudinal block 14 and the camshaft W1 start relative rotation by a low pressure clamp of the work rest WR, and the phase reference pin W3 enters the angle reference groove 20 provided in the angle reference / longitudinal block 14, The rear end stopper ST advances to the forward end by the amount and stops (S4).

  Next, the collet sleeve 8 is drawn into the other cylinder chamber 6B of the piston 7 via the piston sleeve 7A and pulled in the left direction in the figure, and the chuck portion 10A of the collet 10 is contracted to clamp the small-diameter camshaft W1. The workpiece, that is, the camshaft W1 can be clamped by clamping the portion with the small diameter gripping portion 11 (S5). Thereafter, the cam profile grinding can be performed by the rotation operation of the spindle 2 and the back-and-forth movement of a grinding wheel base (not shown).

  When the small-diameter workpiece W1 is clamped using the small-diameter gripping portion 11 described above, the center of the clamping force applied to the collet 10 from the collet sleeve 8 through the tapered surfaces 8B and 10B (the axis of the tapered surface 10B). The center of the direction) and the clamping reaction force (generated by the gripping part) that the collet 10 receives from the workpiece W1 are opposed to each other at the same longitudinal position in the axial direction. Therefore, excessive stress does not act.

  Next, the clamping operation of the large diameter workpiece W2 will be described. Similarly, the piston 7 and the piston sleeve 7A are hydraulically introduced into the cylinder chamber 6A, the collet sleeve 8 is pushed out, and the chuck portion 10A of the collet 10 is opened. Then, as shown in FIG. 6, a large-diameter angle reference / longitudinal block 15 is attached to the tip of the convex portion 4B of the collet chuck device 1 (equipment processing step replacement operation).

  Next, as shown in FIG. 6, a large-diameter camshaft W2, which is a workpiece, is carried onto the work rest WR, and similarly, a phase reference pin W3 press-fitted into the end of the large-diameter camshaft W2 is provided. The rear end stopper ST is moved forward until it comes into contact with the angle reference / longitudinal block 15 and is further pressed, and the work rest WR is subsequently clamped at a low pressure to rotate the spindle 2. The main shaft 2 and the angle reference / longitudinal block 15 and the camshaft W2 start to rotate relative to each other, and the phase reference pin W3 enters the angle reference groove 20 provided in the angle reference / longitudinal block 15, and the rear end stopper ST is correspondingly moved. Advance to the forward end and stop.

  Thereafter, similarly, the collet sleeve 8 is pulled in the left direction by the piston 7, the chuck portion 10 </ b> A of the collet 10 is contracted, and the shaft portion 15 </ b> A of the angle reference / longitudinal block 15 is gripped by the small diameter gripping portion 11. The workpiece, that is, the camshaft W <b> 2 can be clamped by clamping the clamp portion of the camshaft W <b> 2 having a diameter with the large-diameter gripping portion 12.

  When the large-diameter workpiece W2 is clamped using the large-diameter gripping portion 12, the center of the clamping force applied to the collet 10 from the collet sleeve 8 through the tapered surfaces 8B and 10B (the axis of the tapered surface 10B). The clamping reaction force (generated from the gripping portion) that the collet 10 receives from the workpiece W2 is opposed to the axial direction in different longitudinal positions, and a couple is about to be generated in the collet 10. However, the collet 10 simultaneously clamps the shaft portion 15A of the angle reference / longitudinal block 15 by the small-diameter gripping portion 11, so that a part of the clamping force applied to the collet 10 from the collet sleeve 8 through the tapered surface 10B is obtained. Take it. Accordingly, the generation of the couple is suppressed and the deformation amount of the collet 10 is limited, so that the collet 10 can be prevented from being damaged. Therefore, even when a large clamping force is required as in a cam profile grinder, there is no problem that the collet 10 is deformed and damaged by the bending moment generated in the collet 10.

  The collet chuck device 1 of the improved example shown in FIG. 7 is a small diameter that essentially clamps the outer diameter of the shaft portion 15A of the angle reference and long block 15 for the large diameter with the small diameter gripping portion 11 in the collet chuck device 1 described above. It is set slightly smaller than the outer diameter of the workpiece W1. Further, the surface of the large-diameter gripping portion 12 that engages with the large-diameter workpiece W2 is formed in a tapered shape with the tip side closer to the workpiece W. Other configurations are the same as those of the collet chuck device 1 described above.

  In this collet chuck device 1, when the collet sleeve 8 is pulled in the left direction in the figure by the hydraulic cylinder 6, first, the large-diameter gripping portion 12 of the collet 10 contacts the large-diameter work W2 (camshaft) (in the figure). Broken line state). When the collet sleeve 8 is further retracted and moved in the left direction, the collet 10 is pushed by the tapered surface 8B of the collet sleeve 8 and elastically deformed around the contact point with the large-diameter workpiece W2 (camshaft) (in the drawing). Solid line state). The collet 10 is elastically deformed until the small diameter gripping portion 11 comes into contact with the outer diameter of the shaft portion 15A of the angle reference / longitudinal block 15 (which is formed slightly smaller than the outer diameter of the small diameter workpiece W1).

  Due to the elastic deformation of the collet 10, the actual taper angle of the tapered surface 10B of the collet 10 becomes smaller than the taper angle of the tapered surface 8B of the collet sleeve 8. For this reason, the contact position between the tapered surfaces 8B and 10B of the collet 10 and the collet sleeve 8 moves from the vicinity of the center of the contact surface width between the collets 10 to the mouth side of the collet 10 (right direction in the drawing).

  Due to the movement of the contact position, the reaction force caused by the clamping at the large-diameter gripping portion 12 of the collet 10 and the contact position between the tapered surfaces 8B and 10B of the collet 10 and the collet sleeve 8 become substantially the same longitudinal position. A predetermined clamping force can be generated in the large-diameter gripping portion 12 that clamps the ten large-diameter workpieces W2 (camshafts).

  In other words, when the outer diameter of the shaft portion 15A of the angle reference / longitudinal block 15 is substantially equal to the outer diameter of the small-diameter workpiece W1, the clamping force of the collet sleeve 8 has two gripping portions (the large-diameter gripping portion 12 and the small-diameter gripping portion 12). Therefore, if the clamping force required for the grinding process is constant, it is necessary to apply a larger input to the collet sleeve 8 than the normal collet 10.

  However, in this improved example, the outer diameter of the shaft portion 15A of the angle reference / longitudinal block 15 is made slightly smaller than the outer diameter of the small-diameter workpiece W1, so that the shaft portion 15A of the angle reference / longitudinal block 15 and the small-diameter workpiece W1 are reduced. Only in the diameter difference, the collet 10 is elastically deformed so that the actual taper angle of the collet 10 is changed, and the contact position between the collet sleeve 8 and the collet 10 moves to the clamp work W2 side. It is possible to increase the share of the reaction force generated in the grip portion 12 where the longitudinal center positions of the contact surfaces of 8 and the collet 10 do not match. For this reason, a predetermined clamping force can be generated without making the input of the collet sleeve 8 excessive.

  Further, by providing the large-diameter gripping portion 12 with a tapered surface corresponding to the change in the actual taper angle due to the elastic deformation of the collet 10, the large-diameter gripping portion 12 of the collet 10 and the clamp cylindrical surface of the large-diameter workpiece W2 Can be brought into contact with each other in a substantially parallel plane, and the concentration of the clamp load can be avoided, thereby preventing the occurrence of gripping scratches. The tapered surface provided on the large-diameter gripping portion 12 is not limited to a linear conical surface, and if the central portion of the gripping surface is formed on a curved surface slightly bulging to the workpiece W2 side, contact with the workpiece W2 Can be prevented from becoming localized, and the contact state with the workpiece W2 can be further improved.

  Although the collet chuck device 1 used in the cam grinding machine for grinding the cam profile of the camshaft has been described as the workpiece W in the above embodiment, although not shown, the collet chuck device for clamping other cylindrical workpieces. It is not limited to the one that clamps the cylindrical workpiece, and may be a collet chuck device that clamps the cylindrical workpiece from the inner diameter portion.

  Moreover, in the said embodiment, the collet chuck apparatus 1 which arrange | positions the holding parts 11 and 12 which have two types of clamp diameters to the axial direction center part and front-end | tip part of the contact taper surfaces 8B and 10B with the collet sleeve 8 was demonstrated. However, although not shown, two or more gripping portions may be provided with different axial positions on the distal end side in the axial direction.

  Further, the collet chuck device 1 has been described in which the grip portion 11 on the center side has a small diameter and the grip portion 12 on the tip side has a large diameter. However, the grip portion on the center side has a large diameter and the grip portion on the tip side has a small diameter. The collet chuck device may be used.

  Further, although the collet chuck device 1 in which the collet sleeve 8 is moved relative to the collet 10 in the axial direction by the cylinder device 6 has been described, although not shown, the collet is relative to the collet sleeve in the axial direction by the cylinder device. It may be a collet chuck device that is moved.

  In the present embodiment, the following effects can be achieved.

  (A) The collet sleeve 8 disposed on the back surface and the tapered surfaces 8B and 10B are in contact with each other, and the columnar or cylindrical workpiece W is moved from the outer peripheral side or the inner peripheral side by axial relative movement with the collet sleeve 8. In the collet chuck device 1 including the collet 10 in which a plurality of gripping portions 11 and 12 to be clamped are arranged in an axial direction so as to correspond to at least two clamp diameters, of the plurality of gripping portions 11 and 12 One of the axial positions of the collet sleeve 8 and the collet 10 is arranged at or near the central position of the axial width of the contact taper surfaces 8B and 10B. One is arranged on the tip side of the collet 10 from the center position of the axial width of the contact taper surfaces 8B, 10B, and is arranged on the tip side of the collet 10. At the time of clamping by the gripping part 12, the diameter corresponding to the workpiece diameter clamped by the gripping part 11 is set on the gripping part 11 arranged close to the central position of the axial width of the contact taper surfaces 8B, 10B or close to the central position. The workpiece W2 is clamped by the gripping portion 12 disposed on the tip side of the collet 10 while clamping the member 15 provided.

  For this reason, when the workpiece W1 is clamped by the grip portion 11 arranged close to or near the center position, the axial positions of the clamping force received from the contact taper surface 10B and the clamping reaction force received from the workpiece W1 are mutually equal. When the workpiece W2 is clamped by the grip portion 12 on the tip end side, the grip portion 11 on the center position side is connected to the grip portion 11 on the center position side. Since the workpiece W2 is clamped by the grip portion 12 on the distal end side while holding the member 15 having a diameter corresponding to the workpiece diameter to be clamped, the deformation amount of the collet 10 is limited, and the collet 10 can be prevented from being damaged. it can.

  (A) When the collet chuck device 1 clamps the cylindrical workpiece W from the outer peripheral side, the contact taper surface 10B with the collet sleeve 8 is clamped by the gripping portion 12 arranged on the tip side of the collet 10. The outer diameter of the member 15 gripped by the gripping part 11 arranged close to the center position or the center position of the axial width is formed to be smaller than the diameter of the workpiece W1 originally clamped by the gripping part 11. Further, when the collet chuck device 1 clamps a cylindrical workpiece from the inner peripheral side, the axis of the contact taper surface 10B with the collet sleeve 8 is clamped by the grip portion 12 disposed on the tip side of the collet 10. The inner diameter of the member 15 gripped by the grip portion 11 arranged close to the center position of the direction width or close to the center position is formed larger than the diameter of the workpiece W1 originally clamped by the grip portion 11. As a result, the collet 10 is elastically deformed by a difference in diameter from the workpiece W1, the actual taper angle of the collet 10 is changed, and the contact position of the collet sleeve 8 and the collet 10 moves to the tip side of the collet 10, so that the tip side The proportion of the reaction force generated in the grip portion 12 can be increased, and a predetermined clamping force can be generated without making the input from the collet sleeve 8 excessive.

  (C) By forming the gripping surface of the gripping part 12 arranged on the tip side of the collet 10 on an inclined surface where the tip side of the collet 10 is closer to the workpiece W2, the contact with the workpiece W2 becomes parallel and the concentration of the clamp load is concentrated. By being avoided, the occurrence of grabbing scratches can be prevented.

  (D) The collet chuck device 1 is a chuck device for a cam grinder that clamps the vicinity of the end of the workpiece W where the cam shaft angle reference W3 is provided, and sets the axial position of the cam shaft during grinding. In addition, by providing the longitudinal blocks 14 and 15 including the engaging portions 20 that engage with the cam shaft angle reference at the end portions, the cam shaft can be reliably positioned in the axial direction and the rotational direction to be firmly clamped. .

  (E) The above-described longitudinal direction as the member 15 to be gripped by the gripping portion 11 disposed near the central position or the central position of the axial width of the contact taper surface 10B during clamping by the gripping portion 12 disposed on the tip side of the collet 10 By using the block 15, camshafts having a plurality of diameters can be reliably clamped.

  The present invention is described mainly for a collet chuck device used in a cam grinder for grinding a cam profile of a camshaft. However, the present invention is not limited to this, and the present invention is not limited to this. It can be used for a chuck device or a chuck device for clamping a cylindrical workpiece from the inner peripheral side.

Sectional drawing of the collet chuck apparatus which shows one Embodiment of this invention. Sectional drawing of the principal part of the collet chuck apparatus which clamped the small diameter work similarly. Sectional drawing of the principal part of the collet chuck apparatus which clamped the large diameter workpiece similarly. Explanatory drawing of the state which clamped the small diameter work. Explanatory drawing which shows the procedure of a work clamp. Explanatory drawing of the state which clamped the small diameter work. The principal part sectional drawing explaining the collet chuck apparatus of an improved example.

Explanation of symbols

W1, W2 Work W3 Angle reference pin 1 Collet chuck device, chuck device 2 Spindle 3 Rotating face plate 4 Connection face plate 5 Cylindrical member 6 Cylinder device 7 Piston 8 Collet sleeve 10 Collet 11, 12 Grasping part 14, 15 Angle reference and long block

Claims (6)

At least two gripping portions that contact the collet sleeve arranged on the back surface with the tapered surfaces and clamp the columnar or cylindrical workpiece from the outer peripheral side or the inner peripheral side by axial relative movement with the collet sleeve are provided. In a collet chuck device comprising a collet arranged with a plurality offset in the axial direction corresponding to the clamp diameter,
The axial position of one of the plurality of gripping portions is arranged close to the central position or the central position of the axial width of the contact tapered surface of the collet sleeve and the collet, and at least one of the other gripping portions is Arranged on the collet tip side from the center position of the axial width of the contact taper surface,
At the time of clamping by the gripping part arranged on the tip side of the collet, a diameter corresponding to the work diameter clamped by the gripping part is set on the gripping part arranged close to the central position or the central position of the axial width of the contact tapered surface. A collet chuck device, wherein a workpiece is clamped by a gripping portion disposed on a collet tip side while gripping a member provided.   The collet chuck device clamps a cylindrical workpiece from the outer peripheral side, and is clamped by a grip portion disposed on the tip end side of the collet so that the collet chuck device is brought close to the center position or the center position of the axial width of the contact taper surface. 2. The collet chuck device according to claim 1, wherein the member to be gripped by the gripping portion is formed smaller than the diameter of the workpiece that is originally clamped by the gripping portion.   The collet chuck device clamps a cylindrical workpiece from the inner peripheral side, and closes to the center position or the center position of the axial width of the contact taper surface at the time of clamping by a gripping portion disposed on the tip end side of the collet. The collet chuck device according to claim 1, wherein the member gripped by the gripping portion disposed in a manner is formed larger than a diameter of a workpiece that is originally clamped by the gripping portion.   4. The collet chuck device according to claim 2, wherein the gripping portion disposed on the collet tip side has a gripping surface formed on an inclined surface closer to the workpiece than the collet tip side.   The collet chuck device clamps the vicinity of an end portion provided with an angle reference of a camshaft which is a work of a cam grinding machine, and includes a longitudinal block for setting an axial position during grinding of the camshaft, 5. The collet chuck device according to claim 1, further comprising an engaging portion that engages with an angle reference of the camshaft at an end portion of the longitudinal block.   The member to be gripped by the grip portion disposed near the central position of the contact taper surface in the axial direction or in the vicinity of the center position at the time of clamping by the grip portion disposed on the tip side of the collet is the longitudinal block. The collet chuck device according to claim 5.

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