JPH07299616A - Chuck device - Google Patents

Abstract

PURPOSE:To provide a chuck device suitable when both end parts of a long-sized work such as, for example, an engine valve are simultaneously worked. CONSTITUTION:A pair of clamp use pistons 16 and 17 are arranged in a clamp use cylinder 12, and a common fluid chamber 19 is formed between both 16 and 17, and reference members 14 and 15 are fixed to both end parts of the clamp use pistons 16 and 17. Collets 21 and 22 are locked on the clamp use pistons 16 and 17, and taper parts 21b and 22b of the collets 21 and 22 are made lockable on and releasable from taper guide holes 14a and 15a of the reference members 14 and 15, and plural coil springs 20 are contractively installed between the reference members 14 and 15 and the clamp use pistons 16 and 17. An unclamp use piston 24 is arranged in an unclamp use cylinder 23 communicated with the fluid chamber 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck device suitable for simultaneously processing both ends of a long workpiece such as an engine valve.

[0002]

2. Description of the Related Art Conventionally, the present applicant has already proposed a device such as Japanese Utility Model Publication No. 1-1890 as a chuck device for a work when both ends of a long work are simultaneously processed.

This device comprises a sub-casing fixed to one end of a tubular fixed casing, a tubular movable casing movable in the fixed casing and biased toward the sub-casing by a disc spring. A long collet movable in the cylinder of the movable casing is provided, and tapered portions are provided on both outer circumferences of both ends of the long collet so that the collet can expand and contract. The taper guide portion is engaged, and the taper portion on the other end side is engaged with the taper guide portion on the inner circumference of the sub casing to clamp both ends of the work.

The collet is urged toward the sub-casing side through the movable casing by the disc spring so that the taper portion on one end side of the collet is tightened by the taper guide of the sub casing and the taper portion on the other end side is movable casing. Clamp by tightening with the taper guide of
At the time of releasing, the movable casing is pressed and moved in the direction away from the sub casing against the biasing force of the disc spring.

[0005]

However, in the case of the above-mentioned device, the clamping force is influenced by the disc spring force for urging the movable casing, so that the influence of abrasion of the collet or the like greatly affects the reduction of the clamping force. Therefore, in order to keep the clamping force constant, it was necessary to adjust the shim frequently.

Further, since the engaging portion of the collet has one end side as a fixed reference such as a sub-casing and the other end side as a sliding component reference such as a movable casing, the work holding precision is large in the component precision. There is a problem in that, when both are movable parts, especially between the movable casing and the collet, wear is likely to occur at the engaging portions of both.

Further, since taper portions are formed at both ends of a long collet, there is a problem that even if the adhesiveness on one end side is good, if the other end side is worn and the adhesiveness deteriorates, it becomes useless. It was

[0008]

In order to solve the above-mentioned problems and to provide a reliable chuck device, the present application forms a common fluid chamber in a clamp cylinder and an intermediate portion in the clamp cylinder. A pair of clamping pistons, which are arranged as necessary, a pair of reference members fixed to both ends of the clamping cylinder and having tapered guide holes in the center, and a biasing member for biasing the clamping pistons toward each other. Urging means, a pair of collets locked to each clamping piston and having a taper portion on the outer periphery, an unclamping cylinder communicating with a common fluid chamber, and an unclamping cylinder provided in this unclamping cylinder. A clamping piston is provided, and when the clamping piston is urged by the urging means, the taper portion of each collet outer periphery and the taper of each reference member are tapered. Ido hole engaged, it is moved in the direction away by increasing the internal pressure of the fluid chamber to each other each clamping pistons, and so as to disengage the tapered guide hole of the tapered portion and the reference member of the collet circumference.

Further, the urging means is a plurality of coil springs that are compressed between each reference member and the clamping piston on the side concerned.

[0010]

By clamping both ends of the work with a pair of collets, the adhesion of both tapered parts is improved, and only one collet can be replaced independently.

Further, since the taper guide holes of the pair of reference members both serve as a fixed reference, there is little influence of wear of parts or accuracy of parts on clamp accuracy.

Further, by using the coil spring instead of the disc spring, even if the collet part is worn, the clamping force is not reduced so much and the trouble of adjusting the shim is unnecessary. Moreover, by using a plurality of coil springs, it is possible to reduce the size in the longitudinal direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a chuck device of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing the internal structure of the chuck device of the present invention, and FIG. 2 is a rear view of the device as viewed from A in FIG.

The chuck device of the present invention clamps and rotates both ends of an engine valve W as a long work piece as shown in FIG. 1 to rotate the rear side peripheral surface portion Wa of the umbrella portion and the stem base end portion Wb. It is applied to a processing machine 1 that processes simultaneously.

That is, the processing machine 1 is provided with an index shaft portion 2 which is rotatable by a drive unit (not shown) and an index main body 3 which rotates integrally with the index shaft portion 2, and the index main body 3 has an index shaft. Part 2
A pair of casings 10 and 1 at substantially symmetrical positions with respect to
0 (one side not shown) is fixed, and each casing 10
Each of them has a rotary body 4 incorporated therein.

The chuck device 5 of the present invention is incorporated in each of the rotating bodies 4 and 4 so that the engine valves W and W can be clamped by the chuck devices 5 and 5, respectively, and the index shaft 2 is indexed. When the main body 3 is rotated and, for example, the engine valve W clamped by the chuck device 5 of the rotating body 4 on one side is exposed to the processing position,
The engine valve W clamped by the chuck device 5 of the rotating body 4 on the other side can be exposed to the mounting / discharging position.

At the center of the index shaft portion 2, a spindle shaft 6 rotatable with respect to the index shaft portion 2 is provided.
Is provided, and the gear 7 fixed to the tip of the spindle shaft 6 meshes with the idle gear 8. The idle gear 8 meshes with the gear 9 of the rotating body 4.

The rotating body 4 includes a clamping cylinder 12 which is rotatable with respect to a casing 10 via a bearing 11, a gear 9 fixed to an outer periphery of an axial intermediate portion of the clamping cylinder 12, and front and rear bearings. A ring-plate-shaped cover 13, 13 is provided to cover the outside of the casing 11. When the rotation of the spindle shaft 6 is transmitted from the idle gear 8 to the gear 9, the clamping cylinder 12 is rotatable with respect to the casing 10. I have to.

Reference members 14, 15 are attached to the front surface and the rear surface of each clamping cylinder 12, and taper guide holes 14a are formed in the centers of the reference members 14, 15 so that the hole diameters thereof are expanded outward. Is provided.

A pair of left and right clamping pistons 1 having a through hole in the center of the clamping cylinder 12 are provided.
6, 17 are provided.

The clamping pistons 16,
Flanges 16a, 17a projecting from the vicinity of the inner diameter portion toward the other side from each other are provided on the respective facing surfaces of 17
The outer peripheral surface of the flange 16a on one side and the inner peripheral surface of the flange 17a on the other side are in sliding contact with each other via a seal member.
An annular space portion sandwiched by the clamp pistons 16 and 17 is hermetically configured as a fluid chamber 19 described later.

Further, in the embodiment, six circular recesses are provided on the opposite surface side of the clamp pistons 16 and 17, and the coil springs 20 are compressed in the circular recesses. And this coil spring 20, ...
By bringing one side into contact with the inner surfaces of the reference members 14 and 15, the clamping pistons 16 and 17 are urged in a direction in which they approach each other.

Here, each of the clamp pistons 16 and 17 is
Cylindrical collets 21 and 22 are locked in the through holes.

That is, the engine valve W can be inserted into the cylinders of the collets 21 and 22, and the locking protrusions provided on the outer peripheral portion on the base end side have the clamping pistons 16 and 17.
Of the clamping piston 1 by engaging with the concave portion of the inner surface of the through hole of
It is designed to move integrally with 6 and 17.

On the tip side of the collets 21 and 22,
Tapered portions 21a and 22a whose outer diameter expands toward the outside are provided. Further, as shown in FIG. 2, the tapered portions 21a and 22a are formed with three split grooves s in the circumferential direction. The part is expandable and contractible.

Therefore, when both the clamping pistons 16 and 17 are urged in the approaching direction by the coil spring 20, the collets 21 and 22 that are locked to the clamping pistons 16 and 17 are also attached to the inside. The tapered portions 21a and 22a at the respective tips are pressed into contact with the tapered guide holes 14a and 15a of the reference members 14 and 15, and the diameters of the tapered portions are reduced. That is, the engine valve W inserted in the collets 21 and 22 is clamped by the reduced diameter of the tapered portions 21a and 22a.

By the way, a plurality of unclamping cylinders 23 (... In the embodiment) are formed in the clamping cylinder 12, and the unclamping piston 2 is provided inside.
4 are arranged.

Then, these unclamping cylinders 2
The fluid chamber 19 is communicated with the fluid chamber 19 by the communication passages 25, and the unclamping cylinder 23, ... And the pressure of the fluid such as oil sealed in the fluid chamber 19 is moved forward and backward by the unclamping pistons 24. I try to change it dynamically.

When the unclamping pistons 24, ... Are advanced by an operating rod (not shown) to increase the internal pressure of the fluid chamber 19, both clamping pistons 16 and 17 are separated against the coil spring 20 pressure. The taper portions 21a and 22a of the collets 21 and 22 and the taper guide holes 14a and 15a of the reference members 14 and 15 are disengaged from each other.

At this time, the unclamping piston 24, ...
In order to enhance the effect of increasing the pressure of the fluid chamber 19 due to, the total cross-sectional area of the unclamping cylinders 23, ... (The total front surface area of the unclamping pistons 24 ,. (Fluid pressure is clamp piston 16
The area for pressing (17) is made sufficiently large so that the increase in pressure is more important than the movement stroke of the clamp piston 16 (17).

Further, on the front surface of each collet 21, 22,
Stoppers 26, 26 for restricting the projecting stroke of the collets 21, 22 are provided.

At the end of the unclamping cylinder 23, an air bleeding blind plug 27 for bleeding air from a fluid such as oil is provided.

An outline of the operation of the chuck device configured as described above will be described.

Of the pair of rotating bodies 4 incorporated in the index main body 3, when one rotating body 4 faces the machining position, the other rotating body 4 faces the mounting / discharging position to complete the machining. The engine valve W is discharged and a new engine valve W is clamped.

Therefore, at this mounting / discharging position, a pushing member (not shown) for pushing in and inserting the engine valve W from the left side in FIG. 1 and a dispensing member (not shown) for pushing out from the right side in FIG. 1 are provided. Further, an operating rod (not shown) for pressing the unclamping pistons 24, ... Is provided on the same side as the payout member.

When the engine valve W is clamped, the unclamping pistons 24, ... Are moved forward to move the clamping pistons 16 and 17 in the separating direction, and the clamping pistons 16 and 17 are engaged. The collets 21 and 22 to be stopped are advanced to the outside so that the tapered portion 21
a, 22a and the taper guide holes 14a, 15a are disengaged. That is, in this state, the taper portions 21a and 22a of the collets 21 and 22 are in a diameter-expanded state.

Then, in this state, the engine valve W is inserted from the stem side, and the unclamping cylinder 2 is inserted.
By retreating 4, ..., each clamp piston 16, 1,
7 (collets 21, 22) is a coil spring 20, ...
The taper portions 21a and 22a are engaged with the taper guide holes 14a and 15a to reduce the diameter, and are clamped at two points.

At this time, since the taper guide holes 14a and 15a are both fixed references, the taper portions 21a and 22a are fixed.
The degree of close contact with and does not depend on the precision of the parts and the like, and since the collets 21 and 22 are independent from each other on the left and right, the close degree of closeness can be maintained.

Further, since the coil springs 20, ... Are used instead of the conventional disc springs, the collet 21,
Even if 22 is worn, the urging force hardly changes, and there is no need to adjust shims.

Moreover, the plurality of coil springs 20, ...
By disposing the, the chuck device is made compact in the longitudinal direction.

The engine valve W whose both ends are clamped in this way faces the processing position by the rotation of the index main body 3 and is processed while being rotated around the axis by the rotation of the spindle shaft 6, and then again indexed. Then, it is paid out at the mounting / paying position.

It has been proved that the roundness of the engine valve W clamped by the chuck device 5 can be machined within 3 μm, which was around 4 μm in the past.
As for durability, the conventional usage limit was about 100,000 times, but increased to about 360,000 times. Also, replacing the collet, which conventionally required about 60 minutes,
It took about 20 minutes.

[0043]

As described above, the chuck device of the present invention is
When clamping both ends of a long work piece, the pair of collets clamps each independently, so that the taper portion of the collet is more closely attached and the machining accuracy is improved. Moreover, it is convenient because only one collet can be replaced. Further, since the taper guide holes of the pair of reference members that engage with the taper portion of the collet are fixed references, wear of the parts and accuracy of the parts have little influence on the clamp accuracy. Further, since the coil spring is used instead of the disc spring, even if the collet portion is worn, the clamping force is not reduced so much and the trouble of adjusting the shim is unnecessary. Furthermore, by using a plurality of coil springs, it is possible to achieve compactness in the longitudinal direction.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an internal structure of a chuck device of the present invention.

FIG. 2 is a rear view of the device as viewed from A of FIG.

[Explanation of symbols]

 5 Chuck Device 12 Clamping Cylinder 14, 15 Reference Member 14a, 15a Tapered Guide Hole 16, 17 Clamping Piston 19 Fluid Chamber 20 Coil Spring 21, 22 Collet 21a, 22a Tapered Part 23 Unclamping Cylinder 24 Unclamping Piston W Engine valve

Claims (2)

[Claims] 1. A chuck device for clamping both ends of a long workpiece, which device is arranged to form a common fluid chamber in a clamping cylinder and an intermediate portion in the clamping cylinder. A pair of clamping pistons, and a pair of reference members fixed to both ends of the clamping cylinder and having a tapered guide hole in the center,
An urging means for urging the clamping pistons toward each other, a pair of collets that are locked to the clamping pistons and have a tapered portion on the outer peripheral portion, and an ann that communicates with the common fluid chamber. A clamping cylinder and an unclamping piston arranged in the unclamping cylinder are provided, and when the clamping piston is in a state of being biased by the biasing means, the tapered portion of each collet outer periphery and Engage the taper guide holes of the reference member to increase the internal pressure of the fluid chamber and move the clamping pistons in the directions away from each other, and disengage the taper portion of each collet outer periphery and the taper guide hole of each reference member. A chuck device characterized by the above. 2. The chuck device according to claim 1, wherein the biasing means is a plurality of coil springs that are compressed between each reference member and the clamp piston on the side.