JPS5826731Y2 - Workpiece holding device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a workpiece holding device for highly accurate machining of a workpiece in which a reference inner diameter portion of the workpiece and a processing location are connected through a thin wall portion.

The purpose of this invention is to hold the workpiece axis so that it coincides with the spindle axis using the main collet, which expands and engages with the reference inner diameter part, while the auxiliary collet, which expands and engages with the inner diameter gripping part near the processing location, holds the workpiece so that it coincides with the main shaft axis. To stably hold a workpiece without causing deformation of the thin wall part of the workpiece by allowing floating displacement according to the inner diameter gripping part of the workpiece.

Conventionally, in order to process workpieces in which the reference inner diameter part, which is the processing standard, and the processing area are connected by a thin wall part, a filling made of an elastic material such as rubber is inserted into the inner diameter gripping part near the processing part, and the reference inner diameter part is Machining was performed by supporting the inner diameter part near the processing point by the support by the inner diameter part and the elastic force of the elastic filling.

Inserting and removing such an elastic filler into the inner diameter of the workpiece had to be done manually by an operator, so it was not possible to automate the loading and unloading of this type of workpiece.

The present invention has been devised to eliminate such conventional drawbacks and stably hold such a workpiece, and will be described below based on examples.

10 is a headstock; 11 is a main shaft rotatably supported on the headstock 10; 12 is a chuck body fixed to the end surface of the main shaft; this chuck body 12 has a cylindrical portion 13 projecting in the axial direction; An end wall 14 extending radially from the tip of the portion 13 and a main collet 15 projecting further in the axial direction from the end wall 14 are integrally formed.
A groove 16 is cut into the groove, and a plurality of gripping claws that can be expanded and displaced in the radial direction are formed.

The outer peripheral surface 15a of the main collet 15 is the reference inner diameter d of the workpiece W.
1, and the inner circumferential surface 15b is formed with a tapered inner surface that widens toward the tip.

The cylindrical portion 13 has a plurality of slots 17 formed on the circumference, which penetrate in the radial direction and are elongated in the axial direction.
One end of the main shaft side of the chuck body 12 extends to a base 12a of the chuck body 12, and a radial groove 17a is cut in the base 12a through which a protrusion 28 of an operating body 27 (described later) can pass.

18 is an auxiliary collet, and this auxiliary collet 18 is arranged concentrically on the outside of the cylindrical portion 13 and is connected to the chuck body 12.
is fixed to the base 12a of.

This auxiliary collet 18 is divided into a plurality of pieces by grooves 19 to form a plurality of gripping claws that can expand and displace in the radial direction, and the outer circumferential surface 18a of this auxiliary collet 18 is equal to the inner diameter d2 of the workpiece at the processing location. diameter, and the inner peripheral surface 1
8b is formed with a tapered inner surface that widens toward the tip.

Reference numeral 20 denotes a guide member fixed to the end surface of the base 12a of the chuck body 12. This guide member 20 has a guide hole 21 concentric with the center of the main shaft, and one end of the operating rod 22 inserted through the center of the main shaft 11. are fitted.

A taper cone 23 that matches the tapered inner surface of the main collet 15 is fixed concentrically to the tip of the operating rod 22 by a tightening bolt 24, and a threaded portion into which an adjustment nut 25 is screwed is attached to the small diameter shaft portion of the taper cone 23. 26 is formed.

An actuating body 27 movable in the radial direction with respect to this threaded portion 26
The operating body 27 has a protrusion 28 formed with an inclined surface that matches the tapered inner surface of the auxiliary collet 18 and protrudes from the slot 17 of the cylindrical portion 13.

A spring 29 is compressed and inserted between the actuating body 27 and the adjusting nut 25, is pressed in the direction of the operating rod 22, and normally comes into contact with the end surface of the operating rod 22.

The other end of the operating rod 22 is passed through the main shaft 11 and
It is connected to a piston 31 of an actuating cylinder 30 provided at one end of the cylinder.

When the piston 31 of the cylinder 30 is moved forward, the operating rod 22, the taper cone 23, and the actuating body 27 are moved rightward in FIG.

As a result, the gripping claws of the main collet 15 and the auxiliary collet 18 are contracted by elastic force.

In this state, a workpiece as shown by the two-dot chain line is carried in by the illustrated deer carrying device, and is pressed against the reference metal 32 protruding from the end wall 14 by a bushing device (not shown) and positioned in the axial direction. When the piston of the cylinder is moved backward, the operating rod 22, taper cone 23, and operating body 27 move to the left, expanding the main collet 15 and aligning the reference inner diameter of the workpiece with the center of the spindle. Put it out.

At the same time, the auxiliary collet 18 is also expanded, but since the actuating body 27 is pressed by the spring 29 and is supported so as to be freely movable in the radial direction, the auxiliary collet 18 follows the large diameter hole of the workpiece. The respective gripping claws are brought into contact with each other to elastically support the inner circumferential surface of the caroe material connected to the reference inner diameter part at the thin wall part.

This elastically supports the machined part of the workpiece without impeding the centering accuracy of the workpiece by the iron main collet 15, so it is possible to machine the workpiece without reducing the concentricity of the machined surface with respect to the reference inner diameter part. can.

As described above, the present invention has a structure in which the operating body 27 for expanding the auxiliary collet 18 is connected to the operating rod 22 via the spring 29 and supported so as to be freely movable in the radial direction. Even parts connected by thin walls can be machined with high precision, and there is no need to attach and remove elastic fillers from the workpiece as in the past, thereby achieving automation of workpiece loading and unloading. It has the advantage of being able to

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view of the main part, Fig. 2 is a side view seen from the right side in Fig. 1, and Fig. 3 is a cross-sectional view of the main part. FIG. 10... Headstock, 11... Main spindle, 12
... Chuck body, 15 ... Main collet, 18 ... Auxiliary collet, 22 ...
Operating rod, 23...Taper cone, 25...
...Adjusting nut, 26...Threaded part, 27.
...Operating body, 28...Protrusion, 29...
····spring.

Claims (1)

[Scope of utility model registration request] The main collet, which expands and engages with the reference inner diameter of the workpiece, and the auxiliary collet, which expands and engages with the inner diameter, which is larger than the reference inner diameter, are constructed separately, and are fixed to the end face of the rotating main shaft by shifting them in the axial direction. , an actuating body having a tapered cone that engages with the tapered inner surface of the main collet is fixed to the tip of an operating rod inserted through the rotational main shaft, and an inclined protrusion that engages with the tapered inner surface of the auxiliary collet protrudes in the radial direction; A drive that is held movably in the radial direction on the operating rod, a spring is interposed between the operating body and the operating rod to press the operating body toward the rotating main shaft, and the operating rod is moved in the axial direction by power operation. A workpiece holding device connected to a means.