JPS5821605Y2 - Hydraulic holding device - Google Patents

Description

[Detailed description of the invention] The present invention is a hydraulic holding device, namely a mandrel or chuck, for holding a tool or workpiece externally or internally, and in particular has a cylindrical surface on one side and a tapered surface on the other side. a relatively thin expandable cylindrical retaining member having a surface; a rigid body that cooperates with the other tapered surface to firmly retain the retaining member; the other surface side of the retaining member and the rigid body; The present invention relates to a device having an expansion chamber formed between the holding member and a means for supplying hydraulic pressure to the expansion chamber to inflate at least a portion of the holding member.

A hydraulic holding device having the above-mentioned structure is, for example, disclosed in Japanese Patent Publication No. 38-24
However, since the holding member is press-fitted into the main body and held by the tapered surface, the tool holding surface of the holding member can be maintained accurately. Since the expansion part is a tapered part, the thickness is uneven in the longitudinal direction, and the expansion dimension becomes an irregular mountain shape in the longitudinal direction.As a result, it comes into line contact with tools, etc., and does not have a uniform holding force. There were many concerns.

Further, holding members having a uniform thickness are disclosed in, for example, Japanese Patent Publications Nos. 45-22076, 45-29346, and 48-22.
No. 074, and both are fixed to the main body by welding or the like.

Further, in Japanese Patent Publication No. 45-29346, a uniform thin portion is formed in a part of the holding member.

However, the former retains distortion due to welding, etc., and the latter is press-fitted without using a tapered surface, so there are many variations in the degree of press-fit.

Therefore, in both cases, the center portion of the uniform thickness portion bulges out in a mountain shape, which is not a significant improvement, and there is also the problem that the expansion size is not the same for the same oil pressure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic holding device that provides uniform and centered contact with a tool or the like.

The hydraulic holding device according to the present invention will be explained in detail based on the illustrated embodiment.

A first embodiment of holding the tool from the inside, shown in FIG.
A tapered surface 11 and an intermediate circumferential groove 12 are provided on the outer surface of the rigid body 10.
A holding member 13 having a tapered inner surface and a cylindrical outer surface is fitted therein, and a retaining ring 14 prevents the holding member 13 from coming off.

Incidentally, the retaining ring 14 can also be separated from the holding member 13 as in Japanese Patent Publication No. 38-24290.

A pressure chamber 16 is formed by the bore hole 15 of the rigid body 10, and a plurality of radial oil passages 18 are provided between the pressure chamber 16 and an expansion chamber 17 formed between the holding member 13 and the circumferential groove 12.
communicate by.

The passage hole 19 on the right side of the pressure chamber 16 is sealed with a sealing steel ball 20 and a seal screw 21, and the seal screw 21 is removed and the pressure chamber 16 is filled with high viscosity oil.

The left side of the pressure chamber 16 is sealed by an operating screw 24 via a piston 22 that also serves as a seal and a steel ball 23.
When it is rotated by an operating device (not shown), the oil pressure in the pressure chamber 16 increases, and the holding member 13 expands due to the oil pressure in the expansion chamber 17, which is maintained at the same pressure, to hold the tool or the like.

The holding member 13 has a thin wall portion 25.26 of equal thickness at a position facing the expansion chamber 17 and substantially opposite to the circumferential groove 12, and a wall wall of equal thickness between the inner thin portion 25.26. A thick portion 27 is formed.

The inner diameter of the thick portion 27 is made larger than the minimum inner diameter of the tapered surface 11 so as not to interfere with the press-fitting of the holding member 13.

By forming the thin wall portions 25.26 of equal thickness and the thick wall portion 27 of uniform thickness in the center in this way, the thin wall portions 25.26 expand almost uniformly, and the expansion shape is It has a chevron shape with two low, almost flat tops to ensure a secure grip on the tool.

FIG. 2 shows a second embodiment in which the tool is held from the outside, and parts similar to those in the embodiment of FIG. 1 are designated by the same reference numerals with the suffix a.

A tapered surface 11a and an inner circumferential groove 12a are formed on the inner surface of the rigid main body 10a, and a thin cylindrical holding member 13a having a tapered outer surface and a cylindrical inner surface is attached to the tapered surface 1 of the main body 10a.
1a, and then remove the retaining ring 14a with the retaining screw 14a.
' is fixed to the end face of the main body 11a.

A pressure chamber 16a is formed in the bored hole 15a of the rigid main body 10a, and an oil passage 18 is formed between the expansion chamber 17a and the pressure chamber 16a.
Connected by a.

The pressure chamber 16a is closed by an operating screw 24a via a piston 22a and a steel ball 23a, and the operating screw 24a is rotated to control the hydraulic pressure in the pressure chamber 16a and the expansion chamber 17a.

The expansion chamber 17a opens outward through a passage hole 19a and a steel ball 20a, and is closed by a screw 21a and serves as an oil supply port.

Further, the holding member 13a is formed with thin portions 25a, 26a and a thick portion 27a, similar to the first embodiment.

When the operating screw 24a is rotated, the steel ball 23a and the piston 2
2a is moved, and the oil pressure in the pressure chamber 16a increases.

This oil pressure acts on the expansion chamber 17a through the passage 18a, and the portions of the holding member 13a facing the expansion chamber 17a, that is, the thin portions 25a and 26a and the thick portion 27a, expand outward.

Thin portion 25a. The thick portion 26a expands by a larger dimension than the thick portion 27a, and since it has a uniform thickness, it expands almost uniformly and acts uniformly on the outer surface of the tool etc. inserted into the holding member 13a.

As explained above, according to the hydraulic holding device according to the present invention, the holding member 13.13a has the thin portion 2 of uniform thickness.
5.26, 25a, and 26a both expand uniformly to hold the tool, and there is an advantage that the centering of the tool is reliably maintained.

[Brief explanation of the drawing]

The drawings show an embodiment of the hydraulic holding device according to the present invention, FIG. FIG. 2 is a vertical sectional view of the second embodiment, and b is a sectional view taken along the line C--C of a. 10.10a is a rigid body, ILlla is a tapered surface, 13.13a is a holding member, 16.16a is a pressure chamber, 1
7.17a is an expansion chamber, 18.18a is an oil passage, 22.2
2a is the piston, 24.24a is the operating screw, 25.26
．． 25a and 26a are thin portions, and 27.27a are thick portions.

Claims (1)

[Scope of utility model registration request] a relatively thin expandable cylindrical retaining member having one cylindrical surface and a tapered other surface; a rigid body that cooperates with the tapered other surface to firmly retain the retaining member; , a hydraulic holding device comprising an expansion chamber formed between the other surface side of the holding member and the rigid body, and means for supplying hydraulic pressure to the expansion chamber to inflate at least a portion of the holding member. and forming two thin portions of equal thickness in a portion of the holding member facing the expansion chamber, and a thick portion of equal thickness between the circular thin portions. Hydraulic holding device.