JPH07178608A - Chuck for machine tool - Google Patents

Abstract

PURPOSE:To enhance the strength by easing the bending moment acting upon a wedge part without increasing the thickness of a chuck body. CONSTITUTION:A master jaw 2 is formed therein with grooves 8 on opposite sides of the longitudinal middle part thereof, and guide parts 9 are projected on opposite sides of the rear end thereof. At longitudinal positions corresponding to the guide parts 9, wedge parts 10 are projected from the center side end part of the master jaw 2 by a length which is shorter than the longitudinal length of the master jaw 2. A wedge plunger 3 is formed in its outer periphery with a fitting groove 14 in which the center side end of the master jaw 2 is fitted. Wedge grooves 14 which can be engaged with the wedge parts 10 are formed on opposite sides of the fitting groove 14 by a length which is longer than the longitudinal length of the wedge parts 10. The outer peripheral side parts of the wedge grooves 15 are formed with receiving surfaces 17 adapted to be supported at the inner peripheral surface of the plunger slide hole 5 in a chuck body 1 before and after the wedge parts 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck for machine tools, and more particularly to a chuck for obtaining a gripping force by a wedge action.

[0002]

2. Description of the Related Art Generally, in this type of chuck,
The wedge portion of the master jaw and the wedge groove portion of the wedge plunger are on the center side of the chuck and form a cantilever, and a large bending moment acts on this portion.Therefore, when designing the master jaw and wedge plunger, Although it is necessary to set the wedge portion to a large size in consideration of the bending moment, it may not be possible to increase the size due to structural restrictions. Therefore, in Japanese Patent Publication No. 63-44484, conventionally, a portion projecting rearward is provided at the center side end portion of the master jaw, and a reinforcing portion and a wedge portion are formed in this projecting portion, and the wedge groove portion of the wedge plunger is formed. A chuck has been proposed which is configured to reduce the bending moment that acts.

[0003]

However, according to the conventional chuck, there is a disadvantage that the rearward projecting portion of the master jaw increases the thickness of the chuck body. Further, since the wedge portion is formed on the rearward protruding portion, the guide portion of the master jaw and the wedge portion are separated from each other in the front-rear direction, the sliding of the master jaw becomes unstable, and the wedge force is attenuated. There is also a problem that the efficiency of the booster mechanism is reduced.

[0004] Accordingly, an object of the present invention, without increasing the thickness of the chuck body, is to provide a machine tool chuck capable of improving the strength by relaxing the bending moment acting on the wedge groove portion.

[0005]

In order to solve the above problems, the machine tool chuck of the present invention has wedge portions projecting on both sides of the center side end portion of the master jaw, the wedge portions being shorter than the front-rear length of the master jaw. Then, a fitting groove is formed on the outer circumference of the wedge plunger to which the center side end of the master jaw is fitted, and wedge grooves engageable with the wedge portion are provided on both sides of the fitting groove longer than the front-rear length of the wedge portion. In the outer peripheral portion of the wedge groove, a receiving surface is formed which is supported by the inner peripheral surface of the plunger sliding hole of the chuck body before and after the wedge portion.

Further, in the chuck of the present invention, by forming a concave groove extending in the radial direction on the side surface of the master jaw in the front-rear direction, a guide portion extending in the radial direction is provided on both sides of the rear end portion of the master jaw. The wedge portion is provided so as to project at a position in the front-rear direction corresponding to the guide portion.

[0007]

According to the machine tool chuck of the present invention, the outer peripheral portion of the wedge groove is supported by the chuck main body before and after the wedge portion of the master jaw over the entire movement range of the wedge plunger. Therefore, the wedge groove portion can be reinforced by utilizing the rigidity of the chuck body, the bending moment acting on the wedge groove portion can be relaxed, and the wedge portions are provided on both side surfaces of the master jaw. Can be easily increased, and the strength of the chuck can be improved. Since the wedge plunger is not provided with the rearward projecting portion, the thickness of the chuck body 1 can be reduced, and the overall size and weight can be reduced.

Further, since the wedge portion and the guide portion are provided at the positions corresponding to each other at the rear end portion of the master jaw, the master jaw can be smoothly slid in a stable state and the efficiency can be improved without damaging the wedge force. It can occur often.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the machine tool chuck of this embodiment supports three master jaws 2 on a chuck body 1 so as to be slidable in a radial direction, and these are supported by a wedge plunger 3 via a wedge mechanism described later. It is configured so that it can be opened and closed. As shown in FIGS. 2 and 3,
The chuck body 1 has jaw support grooves 4 formed at three equally divided positions on the circumference and a plunger sliding hole 5 at the center. Reference numeral 6 is a bolt for attaching the chuck body 1 to a main shaft (not shown) of a machine tool. Protrusions 4a are provided on both side surfaces of the jaw support groove 4, and the protrusions 4a
A jaw guide groove 4b is formed between the groove and the groove bottom surface.

As shown in FIGS. 4 to 6, the master jaw 2
A concave groove 8 that fits into the convex portion 4a of the jaw support groove 4 (see FIG. 9) is formed on both side surfaces of the intermediate portion in the front-rear direction so as to extend in the radial direction. Guide portions 9 are provided on both sides of the rear end of the master jaw 2 so as to extend in the radial direction by the recessed grooves 8.
It is guided by b. Then, at a position in the front-rear direction corresponding to the guide portion 9, on both sides of the chuck center side end portion of the master jaw 2, a wedge portion 10 constituting one of the wedge mechanisms has a length shorter than the front-rear length of the master jaw 2. It is projected in a slanting shape with the front falling. As shown in FIG. 1, chuck jaws 11 are replaceably mounted on the front surface of the master jaw 2 by bolts 12.

As shown in FIGS. 7 and 8, on the outer circumference of the wedge plunger 3, three fitting grooves 14 into which the center side end of the master jaw 2 is fitted (see FIG. 11) are formed. . Wedge grooves 15 engageable with the wedge portion 10 are provided on both inner surfaces of the fitting groove 14 longer than the front-rear length of the wedge portion 10 (see FIG. 1). In addition, the wedge plunger 3 includes an eaves portion 16 that protrudes inside the fitting groove 14 to form a wedge groove 15, and a receiving surface 17 is formed on an outer surface of the eaves portion 16 that constitutes an outer peripheral side portion of the wedge groove 15. Has been done. The receiving surface 17 is supported by the inner peripheral surface of the plunger sliding hole 5 of the chuck body 1 before and after the wedge portion 10.

In the machine tool chuck of the present embodiment constructed as described above, the master jaw 2 moves outward in the radial direction of the chuck body 1 when the wedge plunger 3 advances due to the wedge action of the wedge groove 15 and the wedge portion 10. The master jaw 2 slides inward in the radial direction and closes when the wedge plunger 3 moves backward. Then, at the forward end position of the wedge plunger 3 (the solid line position in FIG. 1),
A receiving surface 17 having a front-rear length corresponding to the wedge groove 15 is supported by the chuck body 1 in a range indicated by X in FIG. 9, and at the retracted end position (chain line position) of the wedge plunger 3, the receiving surface 17 is shown in FIG. Is supported by the chuck body 1 in the range indicated by Y.

That is, according to the chuck of this embodiment,
The outer peripheral portion of the wedge groove 15 is supported by the chuck body 1 before and after the wedge portion 10 of the master jaw 2 over the entire movement range of the wedge plunger 3. Therefore, the wedge groove 15
The portion can be reinforced by utilizing the rigidity of the chuck body 1, whereby the bending moment acting on the wedge groove 15 is relaxed,
The strength of the chuck can be improved. Further, since the wedge portion 10 of the master jaw 2 is provided on both sides of the master jaw 2, the strength of the wedge portion 10 can be increased. Since the wedge plunger is not provided with the rearward projecting portion as in the conventional case, the thickness of the chuck body 1 can be reduced and the overall size and weight can be reduced.

Further, since the wedge portion 10 and the guide portion 9 are provided at the positions corresponding to each other at the rear end portion of the master jaw 2,
The master jaw 2 slides smoothly in a stable state, and the wedge force is efficiently generated without being attenuated. Therefore, even in the case of a relatively small chuck, it is possible to obtain a strong gripping force capable of coping with high-speed rotation of the spindle.

The present invention is not limited to the above-described embodiments, and the shapes and configurations of the respective parts can be appropriately modified and embodied without departing from the spirit of the present invention.

[0016]

As described in detail above, according to the invention of claim 1, the outer peripheral portion of the wedge groove of the wedge plunger is supported by the chuck body before and after the wedge portion of the master jaw. This has an excellent effect that the bending moment acting on the wedge groove portion can be relaxed and the strength can be improved without increasing the thickness of the chuck body.

According to the second aspect of the present invention, since the wedge portion and the guide portion are provided at the positions corresponding to each other at the rear end portion of the master jaw, the master jaw can be smoothly slid in a stable state and the wedge force can be obtained. Has an effect that can be efficiently generated without attenuating.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a chuck for machine tools showing an embodiment of the present invention.

2 is a front view showing a chuck body of the chuck of FIG. 1. FIG.

3 is a cross-sectional view taken along the line AA of FIG.

4 is a perspective view showing a master jaw of the chuck of FIG. 1. FIG.

5 is a side view of the master jaw of FIG. 4. FIG.

6 is a partially cutaway front view of the master jaw of FIG.

7 is a partially cutaway side view showing a wedge plunger of the chuck of FIG. 1. FIG.

8 is a front view of the wedge plunger of FIG. 7. FIG.

9 is a partial plan view of the chuck of FIG. 1. FIG.

10 is a partial front view of the chuck of FIG. 1. FIG.

11 is a cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

1 ・ ・ Chuck body 2 ・ ・ Master jaw 3 ・ ・ Wedge plunger 5 ・ ・ Plunger sliding hole 8 ・ ・ Recessed groove 9 ・ ・ Guide portion 10 ・ ・ Wedge portion 14 ・ ・ Mating groove 1
5 ... wedge groove, 17 ... receiving surface

Claims (2)

[Claims] 1. A wedge portion shorter than the front-rear length of the master jaw is provided on both sides of the center-side end portion of the master jaw, and a fitting groove into which the center-side end portion of the master jaw is fitted is formed on the outer circumference of the wedge plunger. A wedge groove that can be engaged with the wedge portion is provided on both sides of the fitting groove longer than the front-rear length of the wedge portion, and inside the plunger sliding hole of the chuck body before and after the wedge portion on the outer peripheral side portion of the wedge groove. A machine tool chuck, characterized in that it has a receiving surface supported on the peripheral surface. 2. A guide groove extending in the radial direction is formed on a side surface of an intermediate portion of the master jaw in the front-rear direction, and guide portions extending in the radial direction are provided on both sides of a rear end portion of the master jaw, and the wedge portion serves as the guide portion. The machine tool chuck according to claim 1, wherein the chuck is provided at a corresponding front-rear position.