JP3096837B2 - Lathe workpiece holding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a workpiece holding device for a lathe for holding a workpiece between a main shaft and a tailstock shaft.
The present invention relates to a workpiece holding device suitable for a relatively long workpiece having both ends opened such as a cylindrical shape.

[0002]

2. Description of the Related Art When processing a cylindrical workpiece on a conventional lathe, as shown in FIG. 2, an inner gripping collet chuck 50 and a tailstock shaft (not shown) are provided on a spindle (not shown) side. The head 52 having a conical tapered surface 51 is provided on each side, and the collet 53 of the collet chuck 50 is opened outward in one end opening of the cylindrical workpiece W to open one end of the workpiece W. While grasping from the inside, the tapered surface 51 of the head 52 is pressed against the other end opening of the workpiece W, and a constant thrust is applied in the axial direction to fix the workpiece W,
The outer periphery was processed.

[0003]

However, according to this, since the workpiece W is grasped from the inside by the collet chuck 50 and is completely restrained, if the precision of the collet chuck 50 is poor, the rotation center O1 of the main shaft and the workpiece W are not processed. There has been a problem that the center O2 of the object is shifted, and the longer the length of the workpiece, the lower the processing accuracy. Further, since the movable portion of the opening and closing mechanism of the collet chuck always has friction, the workpiece cannot always be held in the same state.

In view of the above problems, an object of the present invention is to make it possible to accurately hold a cylindrical or other workpiece having both open ends without causing a center shift. The object of the present invention is to enable precision machining even if the object is long, to enable the workpiece to be always held in the same state, and to improve the workability of attaching and detaching the object.

[0005]

According to the present invention, there is provided a workpiece holding apparatus comprising: a mounting base 4 provided on a main shaft 1 side provided with a fixed convex portion 21a having a concave portion 21b at a tip; The fixed head 3 having a truncated cone-shaped taper portion 20 only at the tip end so that a part thereof fits into one end opening of
The convex part 3a at the base end is fixed to the concave part 21 at the tip of the fixed convex part 21a.
b, while the base end surface of the fixed head 3 is in contact with the distal end surface of the fixed convex portion 21a, and is removably fixed to the mounting base 4 on the main shaft 1 side with the screw 22; 2 that the thrust shaft 24 is slidably mounted in the axial direction on the mounting base 26 at the end of the workpiece 2, that the thrust shaft 24 is urged toward the main shaft 1 by a spring 29, At the base end of the push head 7 having a frusto-conical taper portion 23 only at the distal end so that the portion fits, a convex portion 7a
And the convex portion 7a is connected to the concave portion 2 at the tip of the thrust shaft 24.
4c, and the push head 7 is detachably fixed to the distal end of the thrust shaft 24 with the screw 25 while the base end surface of the push head 7 is in contact with the distal end surface of the thrust shaft 24. Features.

[0006]

According to the present invention, both the fixed head on the spindle side and the push head on the tailstock shaft hold the workpiece in a state where a part thereof is fitted into the openings at both ends of the workpiece.
At this time, the push rod given the thrust from the spring pushes the workpiece toward the fixed head, and the frustoconical taper formed on the outer peripheral surfaces of both heads,
It functions to align the center of the spindle with the workpiece from both sides of the workpiece. The workpiece is held between the fixed head and the push head without being gripped by the collet chuck as in the related art, but these heads are also partially inserted into the openings at both ends of the workpiece. In addition to the fact that there is no problem in the stability of holding the workpiece, the workpiece can be easily attached and detached. Both fixed head and push head
It can be easily replaced according to the size (inner diameter) of the opening of the workpiece.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In FIG. 1, a spindle 1 and a tailstock 2 of a lathe are shown.
Oppose each other on the same axis, and the
6 is fixed. And, on the spindle 1 side, a mounting table 4
A fixed convex portion 21a is provided on a seat plate 21 fixed to the front surface of the fixed convex portion 21a, and a fixed head 3 having a frusto-conical tapered portion 20 only at the distal end portion is fixed to the distal end of the fixed convex portion 21a with a screw 22. . At this time, the convex portion 3a at the base end of the fixed head 3 is fitted into the concave portion 21b at the distal end of the fixed convex portion 21a,
Moreover, the screw 22 is passed through the center of the fixed head 3 and tightened while the base end surface of the fixed head 3 is in contact with the distal end surface of the fixed projection 21a.

On the other hand, on the tailstock shaft 2 side, a short push head 7 having a frusto-conical taper portion 23 only at the tip end portion.
However, the protrusion 7a at the base end is fitted into the recess 24c at the tip of the thrust shaft 24, and is fixed to the tip of the thrust shaft 24 with the screw 25. This screw 25 is also a push rod 7
Through the center of the The thrust shaft 24 has a shaft portion 24a.
Is provided with a flange 24b at the rear end thereof.
Is slidably fitted in a guide hole 27 of a mounting base 26 fixed to the tailstock shaft 2, and the shaft portion 24 a is attached to the mounting base 2.
6 is slidably fitted to a thrust bearing 28 fixed to the front surface. And, the thrust shaft 24 is provided with the guide hole 27.
Is urged forward (toward the main shaft 1) by a coil spring 29 inside. The coil spring 29 is guided to expand and contract by a spring guide pin 30 implanted on the rear surface of the thrust shaft 24. Also, on the inner surface of the guide hole 27,
A detent pin 32 that fits into a hole 31 provided in a flange portion 24b of the thrust shaft 24 and restricts rotation of the thrust shaft 24.
Has been planted.

In this apparatus, the tapered portion 20 of the fixed head 3 and the tapered portion 23 of the push head 7 are brought into pressure contact with both open edges of the cylindrical workpiece W to hold the workpiece W. Since the push head 7 is given a thrust by the spring 29, the work W can be held even if the tailstock shaft 2 moves back and forth. Further, by preparing and exchanging the fixed head 3 and the push head 7 having different outer diameters, it is possible to cope with a difference in the size (inner diameter) of the workpiece W.

The workpiece W that can be held by the holding device of the present invention is not limited to a cylindrical one having a full length, but is open at least at both ends (some having holes only at both ends). Included).

[0012]

According to the present invention, the following effects can be obtained.

[0013] A part of the fixed head on the spindle side and a part of the push head on the tailstock shaft are fitted into openings at both ends of the workpiece, and are covered by a push rod given thrust by a spring. The workpiece is pushed toward the fixed head side, and the tapered portions of both heads are pressed against the opening edge of the workpiece and held, so that the center of the spindle and the workpiece can be automatically aligned at the same time as the holding. it can. Therefore,
A workpiece having a cylindrical shape with both ends opened can be held with high precision without causing a center shift, and precision processing can be performed even when the workpiece is long. The workpiece is held between the fixed head and the push head without being gripped by the collet chuck as in the related art.However, these heads and a part thereof are fitted into the openings at both ends of the workpiece, In addition, since a thrust is applied to the push head, the workpiece can always be held in a stable state, and the workpiece can be easily attached and detached.

Since a thrust is applied to the push head by the spring, the above-mentioned holding state can be stably maintained even if the tailstock shaft moves back and forth.

[0015] Since both the fixed head and the push head are detachable with screws, the fixed head and the push head having different outer diameters are prepared and exchanged, respectively, to thereby reduce the size (inner diameter) of the workpiece. Can easily handle differences.

Both the fixed head and the push head are accurately and stably fixed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a workpiece holding device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state of holding a workpiece according to a conventional example.

[Explanation of symbols]

 W Workpiece 1 Main shaft 2 Tail shaft 3 Fixed head 7 Push head 7a Convex portion 20 Tapered portion of fixed head 22 Screw 23 Tapered portion of push head 24 Thrust shaft 24 24c Concave portion 25 Screw 29 Spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-15647 (JP, A) JP-A-63-169209 (JP, A) JP-A-52-8581 (JP, A) 17738 (JP, U) Japanese Utility Model 3-55133 (JP, U) Japanese Utility Model 1-83506 (JP, U) Japanese Utility Model 5-67408 (JP, U) Japanese Utility Model 1-129009 (JP, U) JP-B-58-30084 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23Q 3/12 B23B 23/04 B23Q 3/06

Claims (1)

(57) [Claims] 1. A workpiece holding device for a lathe for holding a workpiece between a main shaft 1 and a tailstock shaft 2. A fixed convex portion having a concave portion 21b at a tip end on a mounting base 4 on the main shaft 1 side. The fixed head 3 having a frusto-conical tapered portion 20 only at the distal end so that a part thereof fits into one end opening of the workpiece whose both ends are opened, and the convex portion 3a at the base end is provided. The fixed convex part 2
In a state where the fixed head 3 is fitted in the concave portion 21b at the distal end of the fixed head 3 and the base end surface of the fixed head 3 is in contact with the distal end surface of the fixed convex portion 21a, the fixed head 3 is detachably fixed to the mounting base 4 on the main spindle 1 side by the screw 22. The thrust shaft 24 is attached to the mounting base 26 at the tip of the tailstock shaft 2.
Is mounted slidably in the axial direction, the thrust shaft 24 is urged toward the main shaft 1 by a spring 29, and only the front end portion is fitted so as to partially fit into the other end opening of the workpiece. A convex portion 7a is provided at the base end of the push head 7 having the frustoconical tapered portion 23, and this convex portion 7a is fitted into the concave portion 24c at the tip of the thrust shaft 24, and the base end surface of the push head 7 is connected to the thrust shaft. Wherein the push head 7 is detachably fixed to the distal end of the thrust shaft 24 by a screw 25 in a state in which the push head 7 is in contact with the distal end surface of the lathe.