JPH0224566Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a collect chuck used in a lathe, and more particularly to a novel collect chuck that allows centering by moving the center of the collect in the radial direction with respect to the spindle.

Prior Art A conventional collector chuck 1 will be explained with reference to FIG.
Slots 2b are formed at three locations a, the slots 2b extend to a small diameter portion 2c to increase the elasticity of the tapered portion 2a, and a large diameter portion 2d is formed following the small diameter portion 2c. A threaded portion 2e for connecting a drawbar (not shown) and a keyway 2f for preventing rotation are formed in the large diameter portion.

The spindle 3 is formed as a single unit as shown in the figure, and a tapered hole 3a into which the taper part 2a of the collet 2 fits and tightens is formed inside the tip part 3b, and the collet 2 is formed in the rear end part 3c. A key 4 that fits into the key groove 2f is implanted.

However, according to the conventional collect chuck 1, the radial position of the center O of the collect 2 with respect to the spindle 3 is always constant and cannot be changed. Therefore, if there is even a slight eccentricity in the spindle 3, the center O of the collet 2 will swing around with the amount of eccentricity as a radius.
This resulted in the workpiece (not shown) also swinging around in a similar manner, which had the disadvantage of interfering with cutting using the lathe. That is, for example, when the machining allowance of the workpiece is small, if the eccentricity of the spin don 3 is relatively large, cutting may be impossible. Even if it is desired to eccentrically process an eccentric cam portion or the like on a workpiece by eccentrically adjusting the required amount, there is an inconvenience in that such centering work cannot be performed at all.

Purpose The present invention was made in order to eliminate the drawbacks of the prior art described above, and its purpose is to fix a spindle to which rotational force is transmitted by a drive flange and a collet in its tapered hole. and a driven flange, and the driven flange is moved relative to the driving flange by the amount of the radial clearance using at least three centering screws, so that centering of the collet can be performed. In addition, by this, the eccentricity of the workpiece gripped by the collet is set to zero, and no matter how small the cutting allowance of the workpiece is, sufficient cutting can be performed.
Another object is to make the radial position of the center of the collet variable with respect to the spindle.
It is possible to provide eccentricity of any size to the center of the collet, and to enable eccentric processing.

Configuration In short, the present invention includes a spindle 13 to which rotational force is transmitted, and a collet 12 housed in the spindle 13 and fixed to its tapered hole 15a, and the collet 12 is moved backward in the axial direction with respect to the spindle 13. In the collect chuck which is designed to firmly grip the workpiece by this, the spindle 13 is connected to the outer cylinder 15c and the inner cylinder
The inner cylinder 15d has a stepped cylindrical shape with an axial keyway 12f formed in the collet 12.
a driven flange 15 having a key 19 implanted therein; and a driving flange 14 formed into a stepped cylindrical shape and fitted into the driven flange 15 with its small diameter portion 14b forming a radial gap c. , and these driven flange 15 and driving flange 14
are removably fixed in the axial direction by fixing screws 16, and are screwed to the driven flange 15 in the radial direction from the outer circumference of the driven flange 15 toward the driving flange 14, and the fixing screws 16 are loosened. The present invention is characterized by the provision of at least three centering screws 18 which enable the center position of the collet 12 to be moved with respect to the drive flange 14 in the state.

The present invention will be explained below based on embodiments shown in the drawings. As shown in FIGS. 1 to 4, the collect chuck 11 according to the present invention includes a spindle 13 to which rotational force is transmitted, and a spindle 13 to which rotational force is transmitted.
The workpiece is firmly gripped by moving the collet 12 axially backward relative to the spindle 13.

Here, the spindle 13 is connected to the driven flange 1
The driven flange 15 has a stepped cylindrical shape having an outer cylinder 15c and an inner cylinder 15d, and the inner cylinder 15d has a key groove formed in the collet 12 along the axial direction. A key 19 is inserted into the inner cylinder 12f to prevent rotation between the inner cylinder 15d and the collet 12. Further, the driving flange 14 has a large diameter portion 14a and a small diameter portion 14.
The large diameter portion 14a has a stepped cylindrical shape with a threaded portion 14d formed on the inner circumferential surface 14c of the large diameter portion 14a.
The small diameter portion 14b is fitted into the driven flange 15 with a radial gap C formed therein. These driven flange 15 and drive flange 14 are removably fixed by a plurality of fixing screws 16 screwed in the axial direction.

Furthermore, it is screwed in the radial direction from the outer periphery 15b of the driven flange 15 toward the driving flange 14,
At least three centering screws 18 are provided which allow centering by moving the position of the center O of the collet 12 relative to the drive flange 14 with the fixing screw 16 loosened.

The tip end 18a of the centering screw 18 is configured to come into contact with the small diameter portion 14b of the drive flange 14 to fix the radial position of the driven flange 15 with respect to the drive flange 14.

Further, like the conventional example shown in FIG. 7, the collet 12 is formed with a tapered surface 12a having the same taper as the taper of the tapered hole 15a of the driven flange 15, and has slots 12b formed at three locations. extends to the small diameter portion 12c to increase the elasticity of the tapered portion 12a, and a keyway 1 is provided in the large diameter portion 12d.
2f and a threaded portion 12e are respectively formed.

As shown in FIG. 4, a second intermediate drawbar 20 is screwed onto the threaded portion 12e of the collet 12.
Further, a first intermediate drawbar 21 is attached to the second intermediate drawbar by a retaining ring 22, and is pulled rightward in the figure by the first intermediate drawbar 21 and the second intermediate drawbar 20, so that the collector 1
The two tapered portions 12a have a small diameter due to the action of the slots 12b, and are configured to be able to grip a round bar-shaped workpiece W as shown in FIG. Further, a main spindle (not shown) of the lathe is screwed onto the threaded portion 14d of the drive flange 14.
The rotational force is transmitted from the main spindle to the spindle 13 so that the collector chuck 11 rotates in a predetermined direction.

Further, as shown in FIG. 5, the diameter of the fixing screw 16 is smaller than the diameter of its mounting hole 15e, and a gap _C1 is formed around the fixing screw 16. The driven flange 15 can be moved in the radial direction relative to the driving flange 14 by this gap _C1 .

Function The present invention is constructed as described above, and its function will be explained below. As shown in FIG. 6, a workpiece W is fixed to the collect chuck 11 according to the present invention, and a lathe is used to turn the collect chuck 11.
When rotated, the collet 12 also rotates in the same direction, and the workpiece W rotates. In this case, when a measurement terminal of a dial gauge (not shown) is brought into contact with the circumference of the workpiece W and the workpiece is rotated, the amount of eccentricity can be read. Therefore, if there is even a slight eccentricity in the work W, the lathe is stopped, the collection chuck 11 is stopped, and the fixing screw 16 is slightly loosened. By rotating the three centering screws 18 in appropriate directions, the gap C between the drive flange 14 and the driven flange 15 changes as shown in FIG. The center O moves, and the eccentricity of the workpiece W, that is, the eccentricity of the center O of the collect 12 becomes zero. This can be read with a dial gauge, and the accuracy can be sufficiently improved to about 1 μm. When the eccentricity of the collet 12 becomes zero, the fixing screws 16 are tightened again to securely fix the driven flange 15 to the driving flange 14. As a result, the amount of eccentricity of the center O of the collet 12 becomes 0, and even if workpieces W of the same size are replaced thereafter, it is possible to perform cutting on workpieces W of the same size one after another without any eccentricity. .
That is, the key 19 implanted in the inner cylinder 15d of the driven flange 15 is inserted into the keyway 12f of the collet 12.
This prevents the collet 12 from rotating and misaligning when replacing the workpiece. In this way, the amount of eccentricity of the workpiece W can be set to zero, so that cutting can be performed no matter how small the cutting allowance is.

In addition, when actively imparting eccentricity to the workpiece W, similarly loosen the fixing screw 16 slightly, apply the dial gauge to the workpiece W, and move one of the three centering screws 18 forward or backward. Possibly the drive flange 1 at the center O of the collet 12
4 can be moved to obtain a desired amount of eccentricity. By gripping the workpiece W with the collet 12 eccentric in this way, the workpiece W can swing around with an arbitrary amount of eccentricity. Therefore, the workpiece W is subjected to eccentric processing such as an eccentric cam part (not shown). becomes possible.

Effects The present invention divides the spindle to which rotational force is transmitted as described above into a drive flange and a driven flange to which the collet is fixed in its tapered hole, and uses a key embedded in the inner cylinder of the driven flange. A keyway formed in the axial direction of the collet prevents rotation between the inner cylinder and the collet, and at least three centering screws maintain the radial clearance between the driven flange and the driving flange. Since the workpiece can be moved by a certain amount, it has the effect of centering the collet, and as a result, the eccentricity of the workpiece gripped by the collet is set to 0, and no matter how small the machining allowance of the workpiece, sufficient cutting can be achieved. It has the effect of being able to be processed. Furthermore, since the radial position of the center of the collet with respect to the spindle is made variable, it is possible to give the center of the collet an arbitrary amount of eccentricity, which has the effect of making eccentric machining possible.

[Brief explanation of the drawing]

Figures 1 to 6 relate to embodiments of the present invention, in which Figure 1 is a perspective view of a main part of the collector chuck with a broken vertical section, Figure 2 is a bottom view of the collector chuck, and Figure 3 is the left side of the collector chuck shown in Figure 2. 4 is a vertical cross-sectional view taken in the direction of the - arrow in Fig. 3, and Fig. 5 is a - in Fig. 4.
6 is a vertical sectional view showing a state in which a workpiece is gripped by the collect chuck shown in FIG. 4; FIG. 7 is a vertical sectional perspective view similar to FIG. 1 of the conventional collect chuck. It is. 11 is collect chuck, 12 is collect, 1
3 is a spindle, 14 is a driving flange, 15 is a driven flange, 15a is a tapered hole, 15b is an outer periphery,
16 is a fixing screw, 18 is a centering screw, and O is the center of the collet.

Claims (1)

[Claims for Utility Model Registration] A spindle 13 to which rotational force is transmitted, and a collet 12 housed in the spindle 13 and fixed to its tapered hole 15a.
In the collet chuck, the spindle 13 is moved backward in the axial direction relative to the spindle 13 to firmly grip the workpiece.
The inner cylinder 15d has a stepped cylindrical shape with an axial keyway 12f formed in the collet 12.
a driven flange 15 having a key 19 implanted therein; and a driving flange 14 formed into a stepped cylindrical shape and fitted into the driven flange 15 with its small diameter portion 14b forming a radial gap c. , and these driven flange 15 and driving flange 14
are removably fixed in the axial direction by fixing screws 16, and are screwed to the driven flange 15 in the radial direction from the outer circumference of the driven flange 15 toward the driving flange 14, and the fixing screws 16 are loosened. A collet chuck characterized in that it is provided with at least three centering screws 18 which enable the center position of the collet 12 to be moved with respect to the drive flange 14 in the state of the collet chuck.