JP3141518B2 - Finger chuck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a finger chuck used by being attached to a spindle of a machine tool.

[0002]

2. Description of the Related Art Conventionally, a finger chuck for gripping a work such as an aluminum wheel having a partially different thickness is provided with a draw sleeve movably in an axial direction at a center portion of a chuck body, and a spider is spherically mounted on the draw sleeve. Conventionally, the spider is tiltably engaged via a seat, and the spider is tilted according to the thickness of the work to grip the work, thereby exhibiting a compensating function.

[0003]

The above-mentioned conventional finger chuck is capable of partially gripping a workpiece having a different wall thickness.
Since the spider tilts and moves around the center of the spherical surface of the inner diameter as the center of rotation, the center of the outer spherical surface of the spider, that is, the center of gravity, moves X amounts in the radial direction according to the inclination of the spider as shown in FIG. . The product of the movement amount X and the weight of the spider becomes an unbalance amount when the finger chuck is rotated, and generates mechanical vibration. This was not negligible because of the deterioration of accuracy and the shortening of the life of the spindle bearing.

Accordingly, an object of the present invention is to prevent the spider from moving in the radial direction caused by compensating, to minimize the fluctuation of the center of gravity of the spider, and to stabilize the rotation during high-speed rotation. An object of the present invention is to provide a finger chuck that ensures the performance.

[0005]

In order to solve the above-mentioned problems, a finger chuck according to the present invention is provided with a draw sleeve movably in the axial direction at a center portion of a chuck body, and a spider is provided on the draw sleeve with a spherical surface. In a finger chuck in which the spider tilts according to the thickness of the workpiece and the jaw grips the workpiece, the outer peripheral surface of the draw sleeve and the inner peripheral surface of the spider are tiltably engaged through the seat. A restricting member for interposing a washer on the draw sleeve and engaging the washer with one of the draw sleeve and the spider through a spherical seat, and restricting movement of the washer in one of the draw sleeve and the spider in the axial direction. The washer is formed so as to be movable in the radial direction while being regulated by the regulating member,
Further, the chuck body is provided with position regulating means for regulating the movement of the spider in the radial direction.

[0006]

[Function] When the spider engaged with the draw bar for jaw operation is pulled in the center axis direction by the draw sleeve, the spider tilts, and each jaw grips a workpiece with a different thickness on the chuck body, and the compensating function is exhibited. You. At this time, the spider follows the thickness of the work with which each jaw comes into contact, and inclines about the spherical center of the inner diameter as the center of rotation, and the center of gravity tries to move, but the spider moves in the radial direction by the position regulating means. At the same time, the washer interposed between the outer peripheral surface of the draw sleeve and the inner peripheral surface of the spider tries to move the spider through the spherical seat while the movement in the axial direction is regulated by the regulating member. The spider moves in the radial direction opposite to the direction in which the spider moves, so that the center of gravity of the spider hardly moves, and the rotational balance during high-speed rotation is well maintained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a finger chuck according to the present invention will be described below with reference to the accompanying drawings. 1 is a longitudinal sectional view of a part of the first embodiment, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG. Is a chuck body (hereinafter, referred to as a body) of a finger chuck, which comprises a front body 1a and a rear body 1b fixed to the front body 1a with mounting bolts 2a, and the front body 1a is connected to the spindle by the mounting bolts 2b. (Not shown), so that the body 1 rotates integrally with the rotation of the spindle.

A body sleeve 3 is fixed to a central portion of the rear body 1b by a mounting bolt 2c, and a rear reduced diameter portion 4a of a draw sleeve 4 reduced in diameter in two steps is fitted into the body sleeve 3. Further, a stepped draw bar 5 that moves back and forth by a rotary cylinder (not shown) or the like is fitted into the draw sleeve 4 and is prevented from falling off by a nut 2d. The center of the front body 1a in front of the draw sleeve 4 is also provided. , A cap 6 is attached by a set screw 2e. A ring plate 7 as a restricting member for restricting movement of a washer 8 in the axial direction, which will be described later, is fitted to the front end of the rear reduced diameter portion 4a of the draw sleeve 4, and is prevented from rotating by a key bolt 7a.

Further, the front reduced diameter portion 4b of the draw sleeve 4
A washer 8 having an outer spherical seat 8a is loosely fitted via a rubber ring 9 and is formed to be relatively movable in the radial direction on the ring plate 7. Then, a spherical hole 10a is formed in the center of the substantially triangular spider 10, and the spherical hole 10a fits tightly with the spherical seat 8a.
The spider 10 is formed to be tiltable along the spherical seat 8a. Thus, the washer 8 is interposed between the outer peripheral surface of the draw sleeve 4 and the inner peripheral surface of the spider 10,
So it can be stored within the thickness range of the spider 10, Wasshi
Even if the chuck 8 is interposed, the bulk of the chuck in the axial direction can be prevented.

The spider 10 has a chuck rotation axis X
A radially fitting hole 10b is formed at a position that divides the circumference of the circle into three equal parts (in the case of two claws and four claws, respectively, two and four equal parts). The spider 10 moves back and forth in conjunction with the forward and backward movements of the draw rod 5 and the draw sleeve 4 operated by a rotating cylinder (not shown). A position restricting portion 1c as a position restricting means is provided on the inner peripheral wall of the front body 1a, and the front end of the spider 10 is fixed to the position restricting portion 1c so that the spider 10 does not move in the radial direction even when tilted.
And stop.

The front body 1b facing each of the fitting holes 10b of the spider 10 is provided with a fitting hole 1d, and the bush 11 is fitted into the fitting hole 1d, and a fixing screw 11a is provided.
To the front body 1a, and the bush 11
A work receiver 12 on which a work W is placed is mounted on a front portion of the work by a mounting bolt 12a. Further, a drawbar holding hole 11b parallel to the chuck rotation axis X is formed in the bush 11, and a jaw actuating drawbar 13 is fitted into the drawbar holding hole 11b so as to be slidable in the axial direction. And a key 1 that engages with the lead groove.
The rotation is regulated by 3a.

The rear end of the draw bar 13 for operating the jaw is reduced in diameter, and the reduced diameter portion 13b is inserted into each fitting hole 10b of the spider 10 with a sufficient gap to allow the inclination of the spider 10. And the nut 15 prevent it from coming off. Furthermore, a draw bar 1 for jaw operation
The jaw 16 is fixed to the distal end of the work 3 by a mounting bolt 16a, but is replaced with an appropriate one according to the shape of the work. In addition, jaw 16
May be fixed to the draw bar 13 for jaw operation by welding or the like.

The operation of grasping a workpiece using the finger chuck configured as described above will be described with reference to FIG. First, when the draw sleeve 4 is moved forward by a rotary cylinder (not shown) or the like via the draw rod 5, the spider 10 moves to the forward end. When the spider 10 moves to the forward end, each jaw actuating draw bar 13 advances and rotates, and the jaw 16 advances forward to open between the work receiver 12, so that the work W _{1 having} a partially different thickness is formed. (Thickness t ₁ <t ₂ ) Workpiece 1
Place on 2.

Next, when the draw sleeve 4 is retracted and the spider 10 is pulled, the draw bar 13 for jaw operation is pulled.
There rotated with retracted, therewith retracts the jaw 16 integral first jaw 16 of the thick t ₂ parts thick abuts on the workpiece W _1. Further pulling the spider 10,
Spider 10 is tilted to follow the other jaw 16 is the thickness of the abutting workpiece (thin part than t ₂ parts, for example, t ₁ part), Compensating function is exerted, each jaw 1
Workpiece W ₁ by the pressing force of 6 it is gripped by the chuck.
Rotating the spindle in this state, it is processed by rotating the workpiece W ₁ together with the body 1.

At this time, as shown in FIG. 4, the spider 10 is inclined around the center of the spherical surface of its inner diameter as the center of rotation, and its center of gravity tends to move in the radial direction by X amount according to its own inclination. The front end of 10 is the position regulating portion 1c
To prevent the spider 10 from moving in the radial direction. At the same time, the washer 8 is pressed by the spider 10 that has tilted the spherical seat 8 a while the movement of the washer 8 in the axial direction is restricted by the ring plate 7. Moves X amount in the opposite direction to the direction you want to move.
The center of gravity of the spider 10 hardly moves, so that the rotation balance at the time of high-speed rotation is well maintained, processing accuracy can be ensured, and the life of components such as the spindle bearing can be prevented from being shortened. Further, since the movement of the spider 10 in the radial direction is prevented, each fitting hole 10
Since there is no need to allow a gap corresponding to the movement amount X of the spider 10 between the b and the reduced diameter portion 13b of the jaw actuating draw bar 13 to be inserted therein, the washer on the thrust surface can be dispensed with.

FIG. 5 shows a second embodiment of the present invention.
The position restricting portion in the embodiment is provided at a position different from that of the first embodiment. The other configuration is completely the same as that of the first embodiment, and the same components are denoted by the same reference numerals. The effects are exactly the same as those of the first embodiment, and the description thereof is omitted. In the present embodiment, an insertion hole 20 having a spherical seat 20a formed on the washer 8 side is formed at an intermediate portion between the fitting hole 10b and the washer 8 in the spider 10, and the movement of the spider 10 is prevented in the insertion hole 20. A stopper pin 21 is inserted, and both ends 21a of the stopper pin 21 are fixed to the front body 1a and the rear body 1b, respectively. Therefore, even if the spider 10 attempts to move in the radial direction, the spherical seat 20 a
, The movement is prevented, and the same effect as in the first embodiment is obtained.

FIG. 6 shows a third embodiment of the present invention.
The washer is engaged with the draw sleeve via the spherical seat, and a restriction member for restricting the movement of the washer in the axial direction is provided on the draw sleeve. The other configuration is exactly the same as that of the first embodiment. The same components are denoted by the same reference numerals, and their operations and effects are exactly the same as those of the first embodiment, so that the description thereof will be omitted. In the present embodiment, a spherical seat 30a is formed on the head of the draw sleeve 30, the spherical hole 31a of the washer 31 is closely fitted to the spherical seat 30a, and an annular groove 31b is provided on the lower peripheral wall of the washer 31. The lower protrusion 33a of the spider 33 is fitted in the groove 31b via a rubber ring 32 so as to be movable in the radial direction. Further, a ring plate 34 as a regulating member for regulating the movement of the washer 31 in the axial direction is fitted below the spherical seat 30a of the draw sleeve 30.

According to this configuration, when the draw sleeve 30 is retracted, the spider 33 tilts to follow the thickness of the work and presses the washer 31. Since the washer 31 moves in the direction opposite to the direction in which the spider 33 moves along the spherical seat 8a while the movement of the washer 31 in the axial direction is restricted by the ring plate 34, its center of gravity hardly moves. The rotation balance during high-speed rotation is well maintained.

In each of the above embodiments, the restricting member for restricting the movement of the washer in the axial direction is provided on the draw sleeve side, but may be provided on the spider side. Other details such as the configuration and the shape of parts can be appropriately changed without departing from the purpose and spirit of the present invention.

[0020]

As described in detail above, according to the present invention,
Even if the spider tilts and can exert compensating function, it can prevent the spider from moving in the radial direction and reduce the fluctuation of the center of gravity of the spider, so rotation stability at high speed rotation In addition, the processing accuracy can be improved, and the shortening of the life of the parts can be prevented. In addition, since the washer is interposed between the outer peripheral surface of the draw sleeve and the inner peripheral surface of the spider and can be stored within the thickness range of the spider, even in the type in which the washer is interposed, the bulk of the chuck in the axial direction is increased. It has excellent utility such as reduction of burrs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention, with a part thereof broken away.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is an explanatory diagram showing movement of a center of gravity due to tilting of a spider.

FIG. 5 is a longitudinal sectional view in which a part of a main part of a second embodiment of the present invention is broken.

FIG. 6 is a longitudinal cross-sectional view of a part of a main part of a third embodiment of the present invention, which is cut away.

[Explanation of symbols]

1 · · · chuck body, 1a · · · front body, 1b · · ·
Rear body, 1c ... Position regulating part, 4 ... Draw sleeve, 7 ... Ring plate, 8 ... Washer, 8A ...
Spherical seat, 10 ・ Spider, Drawbar for 13 ・ Jaw operation, 16 ・ Jaw, W ・ Work.

Claims (1)

(57) [Claims] A draw sleeve is provided at the center of the chuck body so as to be movable in the axial direction, and a spider is tiltably engaged with the draw sleeve via a spherical seat, and the spider is tilted according to the thickness of the workpiece. Then, in the finger chuck in which the jaws grip the work, a washer is interposed between the outer peripheral surface of the draw sleeve and the inner peripheral surface of the spider, and the washer is attached to either the draw sleeve or the spider. Along with one of them, a spherical member is engaged via a spherical seat, and a restricting member for restricting movement of the washer in the axial direction is provided on one of the draw sleeve and the spider, and the washer is restricted in the radial direction while being restricted by the restricting member. The chuck body is provided so as to be movable, and the chuck body further includes position regulating means for regulating movement of the spider in the radial direction. Finger chuck, wherein the door.