Chuck device

Abstract

To enable stable implementation of high-precision centering, and thereby high-precision processing, by maximally preventing a situation where axial positioning of a shaft-shaped workpiece with small diameter parts and a large diameter part adversely affects its centering due to gripping of the small diameter parts from the outside in a radial direction.SOLUTION: A chuck device 10 comprises: gripping parts 16, 17 capable of gripping small diameter parts 2a, 2b of a shaft-shaped workpiece 1 from the outside in a radial direction; and an axial positioning part 15 which abuts on an axial end surface 4 between the small diameter parts 2a, 2b and a large diameter part 3 in order to perform axial positioning of a shaft-shaped workpiece 1. An abutting surface 18 of the axial positioning part 15 can move by following an inclination of the axial end surface 4 relative to an axial direction of the small diameter parts 2a, 2b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chuck device, and more particularly to a technique for chucking an axial workpiece with centering. [Background technology]

[0002] For example, in turning an axial workpiece such as an input shaft, a chuck device capable of gripping the axial workpiece in a centered state is used. This type of chuck device generally has a plurality of claws as a gripping portion provided at the front part of the chuck device body, which are moved radially to grip the axial workpiece so that the central axis of the axial workpiece coincides with the rotation axis of the lathe.

[0003] In addition, in this case, the chuck device is provided with a stopper that abuts against the end face of the flange of the axial workpiece, and by abutting this stopper against the end face of the flange, it is possible to position the axial workpiece (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-302484 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, since axial workpieces such as input shafts are mass-produced parts, a certain degree of tolerance must be allowed for coaxiality, squareness, and the like. For example, when an axial workpiece is gripped using a chuck device as described in Patent Document 1, the claw portion positions the axial part based on the gripping surface (the outer peripheral surface of the axial part), whereas the stopper positions the flange portion based on the end face of the flange portion. Therefore, if there is a corresponding variation in the squareness of the flange end face relative to the central axis of the axial part, the positioning by the stopper may adversely affect the positioning by the gripping part (claw portion). This makes it difficult to stably obtain high machining accuracy.

[0006] In view of the above circumstances, the technical problem to be solved in this specification is to prevent, as much as possible, a situation in which the axial positioning of a shaft-shaped workpiece having a small diameter portion and a large diameter portion has a negative effect on centering due to gripping the small diameter portion from the radial outside, thereby enabling high-precision centering and, ultimately, high-precision machining to be performed stably. [Means for solving the problem]

[0007] The above-mentioned problems are solved by a chuck device according to the present invention, which is a chuck device for chucking and centering a shaft-shaped workpiece having an overall shaft shape and integrally including a relatively small diameter portion and a relatively large diameter portion, and is characterized in that the chuck device includes a gripping portion for gripping the small diameter portion from the radial outside and an axial positioning portion for abutting against an axial end face between the small diameter portion and the large diameter portion to enable axial positioning of the shaft-shaped workpiece, and the abutment surface of the axial positioning portion is configured to move in accordance with the inclination of the axial end face of the small diameter portion with respect to the axial direction.

[0008] In this way, in the chuck device according to the present invention, the abutment surface of the axial positioning portion for abutting against the axial end face between the small diameter portion and the large diameter portion of the axial workpiece to position the axial workpiece in the axial direction is configured to move in accordance with the inclination of the axial end face of the small diameter portion relative to the axial direction. By configuring in this way, the abutment surface of the axial positioning portion moves in accordance with the direction of the axial end face to abut against the axial end face. Therefore, it is possible to avoid a situation in which the axial positioning by the axial positioning portion adversely affects the centering by the gripping portion, and to stably center the small diameter portion. Therefore, it is possible to stably perform high-precision machining of the chucked axial workpiece.

[0009] In the chuck device according to the present invention, the axial positioning portion may be configured with a spherical bearing whose inner ring is capable of abutting against the axial end surface.

[0010] By configuring the axial positioning portion in this manner, a spherical bearing can be disposed radially outside the small diameter portion with the small diameter portion inserted through the through hole of the inner ring. With a spherical bearing, the abutment surface on the inner ring (for example, one side end surface of the inner ring) can always rotate around a fixed reference point. This makes it possible to freely receive the axial end surface between the small diameter portion and the large diameter portion by following the inclination of the abutment surface while maintaining high axial positioning accuracy. Effect of the Invention

[0011] As described above, according to the chuck device of the present invention, the axial positioning of an axial workpiece having a small diameter portion and a large diameter portion can be prevented as much as possible from causing a situation in which centering is adversely affected by gripping the small diameter portion from the radial outside, making it possible to stably perform high-precision centering and, ultimately, high-precision machining. [Brief description of the drawings]

[0012] [Figure 1] 1 is a plan view showing an overall configuration of a chuck device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the details of a chuck device according to one embodiment of the present invention will be described with reference to the drawings.

[0014] Fig. 1 is a cross-sectional view showing the overall configuration of a chuck device 10 according to one embodiment of the present invention. As shown in Fig. 1, this chuck device 10 is a type of chuck device called a pin arbor chuck, and includes a chuck body 11, pin arbors 12 and 13 that are slidable relative to the chuck body 11, a driving member 14 that is connected to the pin arbors 12 and 13 and is capable of driving the pin arbors 12 and 13, and an axial positioning portion 15.

[0015] In this embodiment, multiple (e.g., three) pin arbors 12, 13 are arranged around the central axis X of the chuck device 10 and are arranged at a predetermined angle with respect to the central axis X, and each pin arbors 12, 13 is configured to be slidable relative to the chuck body 11 while maintaining that angle.

[0016] In addition, in this embodiment, the first pin arbor 12 and the second pin arbor 13 are each arranged at equal intervals in the circumferential direction around the central axis X in multiple numbers (e.g., three of each) so that two different points in the axial direction of the axial workpiece 1 (indicated by a two-dot chain line in Figure 1) to be chucked can be gripped from the radially outside.

[0017] Here, the shaft-shaped workpiece 1 to be chucked is, for example, an input shaft formed by forging, and integrally has a shaft portion 2 and a flange portion 3 provided at one end of the shaft portion 2. In this case, a first claw portion 16 capable of gripping a portion of the shaft portion 2 that is relatively small in diameter and will eventually be formed with a spline portion (small spline portion 2a) from the radially outer side is provided at one axial end side of each first pin arbor 12. Also, a second claw portion 17 capable of gripping a portion of the shaft portion 2 that is relatively large in diameter and will eventually be formed with a spline portion (large spline portion 2b) that is located on the flange portion 3 side in the axial direction from the small spline portion 2a from the radially outer side is provided at the other axial end side of each second pin arbor 13. In this embodiment, three first claw portions 16 and three second claw portions 17 are provided. In this case, the small spline portion 2a and the large spline portion 2b correspond to the small diameter portion according to the present invention, and the flange portion 3 corresponds to the large diameter portion according to the present invention. Also, the first claw portion 16 and the second claw portion 17 correspond to the gripping portion according to the present invention.

[0018] The axial positioning portion 15 abuts in the axial direction with the axial end face 4 between the shaft portion 2 and the flange portion 3 of the axial workpiece 1, enabling axial positioning of the axial workpiece 1, and the abutment surface 18 of the axial positioning portion 15 is configured to move in accordance with the inclination of the axial end face 4 relative to the axial direction of the shaft portion 2 (i.e., the direction along the central axis of the shaft portion 2).

[0019] In this embodiment, the axial positioning portion 15 is configured with a spherical bearing 19. In this case, one side end face of the inner ring 20 becomes the abutment surface 18, and the outer ring 21 is fixed to the chuck body 11 via a mounting portion 22. In Fig. 1, the outer ring 21 is fixed to the inner periphery of the annular mounting portion 22. In this case, the outer ring 21 is fixed to a predetermined axial position with respect to the chuck body 11 so that the abutment surface 18 is at a predetermined axial position in an attitude in which the central axis of the inner ring 20 coincides with the central axis X of the chuck device 10.

[0020] The chuck device 10 having the above-mentioned structure is attached in a state in which its central axis X coincides with the central axis that is the center of rotation of a lathe (not shown).

[0021] Next, an example of a method for chucking the shaft-shaped workpiece 1 using the chuck device 10 having the above configuration will be described.

[0022] First, as shown in Fig. 1, the shaft-shaped workpiece 1 is introduced to the center position of the chuck device 10 with the shaft portion 2 facing the chuck device 10. At this time, the shaft-shaped workpiece 1 is introduced to the center position of the chuck device 10 while the shaft portion 2 is inserted into the inner periphery of an inner ring 20 of a spherical bearing 19 serving as an axial positioning portion 15. Then, the axial end face 4 between the outer periphery of the shaft portion 2 and the outer periphery of the flange portion 3 is brought into contact with the abutment surface 18, which is the side end face of the inner ring 20. This allows the shaft-shaped workpiece 1 to be positioned in the axial direction relative to the chuck device 10.

[0023] Next, the driving member 14 is driven by a driving device (not shown) to move the driving member 14 to the rear side of the chuck device 10 (left side in FIG. 1). Then, the first pin arbors 12 and the second pin arbors 13 connected to the driving member 14 are slid toward the rear side at a predetermined angle relative to the chuck body 11. As a result, the first claw portions 16 provided one by one at one axial end (rear end) of each of the first pin arbors 12 move toward the rear while moving radially inward toward the central axis X, and grip the small spline portion 2a of the shaft portion 2 while drawing it toward the rear side. In addition, the first claw portions 16 grip the small spline portion 2a in the process of moving synchronously from the radial outside toward the common central axis X, thereby simultaneously centering the small spline portion 2a with respect to the central axis X.

[0024] In this embodiment, the multiple second claw portions 17 provided one each on the other axial end (front end) of each second pin arbor 13 move rearward while moving radially inward toward the central axis X, gripping the intended large spline portion 2b of the shaft portion 2 while pulling it rearward. In addition, the multiple second claw portions 17 grip the intended large spline portion 2b in the process of synchronously moving from the radially outer side toward the common central axis X, thereby simultaneously centering the intended large spline portion 2b with respect to the central axis X.

[0025] In this manner, chucking and centering of the shaft-shaped workpiece 1 is performed. Thereafter, it becomes possible to precisely machine a center hole 6 in the rear end surface 5 of the flange portion 3 using a lathe. This center hole 6 can be used as a reference hole when turning or grinding the outer periphery of the shaft portion 2 in a subsequent process.

[0026] As described above, in the chuck device 10 according to this embodiment, the abutment surface 18 of the axial positioning portion 15 is configured to move in accordance with the inclination of the axial end face 4 with respect to the axial direction of the shank 2, so that the abutment surface 18 of the axial positioning portion 15 moves in accordance with the actual orientation of the axial end face 4 and comes into abutment with the axial end face 4. To explain in detail in accordance with the present embodiment, by the operation of the first jaw portion 16 and the second jaw portion 17 described above, the shank 2 of the shaft-shaped workpiece 1 is gripped in a position and attitude such that the central axis of the shank 2 coincides with the central axis X of the chuck device 10 as a whole. Here, for example, if the normal direction of the axial end face 4 is inclined with respect to the central axis of the shaft portion 2, the above-mentioned gripping operation causes the normal direction of the axial end face 4 to be inclined with respect to the central axis X of the chuck device 10. However, since the abutment surface 18 can move (tilt here) following the axial end face 4, the abutment surface 18 can receive the axial end face 4 in a state in which the abutment surface 18 is inclined by the amount of inclination of the normal line of the axial end face 4 with respect to the central axis of the shaft portion 2 as the shaft portion 2 is retracted. Therefore, the influence of receiving (contacting) the axial end face 4 with the abutment surface 18 on the centering of the shaft portion 2 can be eliminated, and the centering of the shaft portion 2 can be stably performed. Therefore, it becomes possible to stably perform high-precision machining of the chucked shaft-shaped workpiece 1. For the above-mentioned reasons, the present invention is useful for a chuck device 10 of the type that grips the shaft-shaped workpiece 1 while retracting it, as in this embodiment.

[0027] In this embodiment, the axial positioning portion 15 is configured with a spherical bearing 19, and the inner ring 20 of the spherical bearing 19 can abut against the axial end face 4. That is, it is configured as the abutment surface 18. With the spherical bearing 19, the abutment surface 18 provided on the inner ring 20 can always rotate about a fixed reference point (the center point of the outer peripheral raceway surface of the inner ring 20 and the center point of the inner peripheral raceway surface of the outer ring 21). Therefore, it is possible to freely receive the axial end face 4 by following its inclination while maintaining high axial positioning accuracy.

[0028] Although one embodiment of the present invention has been described above, the chuck device according to the present invention can have configurations other than those described above without departing from the spirit of the invention.

[0029] For example, in the above embodiment, the axial positioning portion 15 is configured by the spherical bearing 19, and one side end surface of the inner ring 20 of the spherical bearing 19 is the abutment surface 18 against the axial end surface 4, but of course other configurations are possible. For example, although not shown, a structure in which a plate-shaped member having the abutment surface 18 is supported by multiple elastic members that expand and contract in the axial direction may be used. In this case, each elastic member has a different expansion and contraction mode, so that the plate-shaped member having the abutment surface 18 can receive the axial end surface 4 while freely changing its posture. Of course, as long as the abutment surface 18 moves in accordance with the axial end surface 4, the axial positioning portion 15 can have any configuration.

[0030] In the above explanation, a double-pin arbor type chuck device has been exemplified as the chuck device 10, but the present invention can of course be applied to chuck devices of other types. In other words, the present invention can be applied to a chuck device of any configuration as long as it can axially position the shaft-shaped workpiece 1 by axially abutting the axial end face 4 between the small diameter portion and the large diameter portion of the shaft-shaped workpiece 1 to be chucked.

[0031] In the above explanation, the axial workpiece 1 is an input shaft having a flange portion 3 integrally formed at one end of the shaft portion 2, but it is of course possible to chuck an axial workpiece having a shape other than that described above. In other words, the shape of the axial workpiece 1 to be chucked is arbitrary as long as it is axially shaped as a whole and the axial end face between the small diameter portion and the large diameter portion can be received by the abutment surface 18. [Explanation of symbols]

[0032] 1 Axis workpiece 2 Shaft section 2a Small spline planned section 2b Large spline planned section 3 Flange 4 Axial end face 5 Rear end surface 6 Center Hole 10 Chuck device 11 Chuck body 12 First pin arbor 13 Second pin arbor 14 Driving member 15 Axial positioning part 16 First claw part 17 Second claw part 18 Contact surface 19 Spherical bearings 20. Inner Circle 21 Outer ring 22 Mounting part X center axis

Claims

1. A chuck device for chucking and centering a shaft-shaped workpiece having an overall shaft shape and integrally including a relatively small diameter portion and a relatively large diameter portion, a gripping portion capable of gripping the small diameter portion from a radially outer side; a chuck device including an axial positioning portion that abuts against an axial end surface between the small diameter portion and the large diameter portion to enable axial positioning of the shaft-shaped workpiece, A chuck device, characterized in that the abutment surface of the axial positioning portion is configured to move in accordance with the inclination of the axial end surface with respect to the axial direction of the small diameter portion.

2. The chuck device according to claim 1 , wherein the axial positioning portion is configured as a spherical bearing having an inner ring capable of abutting against the axial end surface.

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