JPH10122285A - Manufacture of cylindrical spring and cylindrical spring produced thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a cylindrical spring, the shapes and sizes of whose outer/ inner diameters, length and end surface are precise by forming a spiral groove to a spring raw material processed cylindrically. SOLUTION: One end surface 1 of a longitudinal direction is processed in a plane shape, after clamping a spring raw material to the chuck of a lathe and processing outer/inner diameters (a), (b) and a length (c) for getting a required size. The spring raw material processed in this cylindrical shape is sent to an axis direction by using a metal saw or an endmill while rotating the cylindrical spring raw material around an axis and a spiral groove 3 matched with the spring dimensions of a desired spring is cut and formed. After forming the spiral groove 3, the other end surface 5 is processed in a plane shape after cutting to a prescribed length (c). Thus, after processing while leaving a clamp margin to the cylindrical spring raw material, it is desirable to cut the clamp margin finally. The spiral groove 3 can be formed by a discharged processing by a wire electrode or a bar shape electrode and also by the grinding process by a disk shape grinding wheel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cylindrical spring in which the shape of the spring is defined by an outer diameter, an inner diameter, a length, and the number of turns, and a cylindrical spring manufactured by the method.

[0002]

2. Description of the Related Art As coil springs, compression and extension coil springs manufactured by spirally winding a linear spring material having a circular, square or rectangular cross section and quenching as necessary are generally known. ing.

[0003]

A coil spring is formed by spirally winding a linear spring material around a mandrel. However, due to the characteristic (spring back) of the linear spring material, a coil spring is formed. The inner diameter of the spring is machined larger than the diameter of the mandrel. For this reason, it is difficult to accurately process the outer diameter and the inner diameter of the coil spring into desired shapes and dimensions. Furthermore, since the coil spring is processed from a linear spring material, the end face shape in the length direction of the coil spring cannot be processed into a planar shape.

Therefore, it is conceivable that after the linear spring material is processed into the shape of the coil spring, the inner diameter, outer diameter, and end face are additionally machined to the desired shape and size with high precision. Due to the operation, it is very difficult to perform such additional processing with high accuracy. Therefore, in the conventional coil spring, the fitting accuracy with the mating member and the sitting accuracy of the end face in the length direction cannot be realized with high accuracy.

In the case where a spring which generates a strong spring force by being attached to a narrow place such as a spindle device of a machine tool is required, a coil spring machined from a linear spring material has a small thickness corresponding to the attachment portion. Since a spring material must be used, a strong spring force cannot be generated. In order to increase the spring force, it is necessary to use a thick spring material, and the mounting dimension becomes large.

For example, when a compression coil spring is used as a tool clamping means of a spindle device of a machine tool which rotates at a high speed, the spindle is liable to be fitted to a mating member (draw bar or spindle) or to have a poor end surface in the longitudinal direction. When rotating at high speed, imbalance occurs and vibration occurs, which adversely affects machining accuracy.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a manufacturing method for easily manufacturing a cylindrical spring having a high accuracy in outer dimensions, inner diameters, lengths, end faces, and the like, and a cylindrical spring manufactured by the method. And

[0008]

SUMMARY OF THE INVENTION A cylindrical spring material is produced in accordance with spring specifications such as a desired outer diameter or inner diameter of a spring, length, wire diameter, number of turns, and the like. A method is provided for manufacturing a cylindrical spring in which a groove is machined to manufacture a spring having desired spring specifications.

[0009]

According to the present invention, the processing suitable for the spring diameter such as the outer diameter or inner diameter and the length, the wire diameter, the number of turns, etc. of the spring can be performed with high precision at the stage of processing the spring material into a cylindrical shape. By forming a spiral groove in the cylindrical spring material using a machining method such as cutting, electric discharge machining, etc., to produce a cylindrical spring with the required spring specifications, the outer diameter, It is possible to manufacture a cylindrical spring having a highly accurate shape and dimensions such as an inner diameter, a length, and an end face.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B show an embodiment of a cylindrical spring manufactured by the manufacturing method of the present invention. FIG. 1A is a top view, FIG. 1B is a side view, and FIG. 2 is manufactured by the manufacturing method of the present invention. FIG. 3 illustrates another embodiment of a shaped cylindrical spring;
(A) is a top view, (b) is a side view, and FIG. 3 is a cross-sectional view of a spindle device using a cylindrical spring according to the embodiment of the present invention as a compression spring for tool clamping means.

The manufacturing process of the cylindrical spring shown in FIG. 1 is as follows. After the spring material is clamped on the chuck of the lathe and the outer diameter a, the inner diameter b, and the length c, which are the required dimensions, are processed, the one end face 1 in the length direction is processed into a flat shape. Using a metal saw or an end mill, the spring material processed into a cylindrical shape is fed in the axial direction while rotating the cylindrical spring material around the axis, and the spiral groove 3 that matches the spring specifications of the desired spring is cut and formed. . After the spiral groove 3 is formed, the spiral groove 3 is cut into a predetermined length c, and the other end surface 5 is processed into a flat shape. In this way, it is preferable to process the cylindrical spring material while leaving a clamp margin, and finally cut the clamp margin. The spiral groove 3 can also be formed by electric discharge machining using a wire electrode or a rod-shaped electrode. Further, the grinding can be performed by a disk grinding wheel. Quenching may be performed after processing,
If it is acceptable to use the material as it is, use it as it is and use it according to the situation. Of course, it is necessary to use a material that can exhibit the performance as a processed spring.

As described above, since both end surfaces 1 and 5 in the longitudinal direction of the cylindrical spring 7 are formed in a flat shape, they are used by applying a compressive force to both end surfaces 1 and 5 of the spring 7. At this time, a uniform pressure can be applied to the spring 7, that is, a uniform load can be applied to the pressed body.

Therefore, when the spring 7 is used, it can be used in a precision fitting state by fitting with the mating member.
It can be used as an outer diameter (outer peripheral surface 9) reference or an inner diameter (inner peripheral surface 11) reference.

Further, as shown in FIG. 1, the spiral groove 3 is formed on the end face 1 in the longitudinal direction of the spring material so that the annular support parts 15 and 17 which are not the spring parts 13 are formed at both ends in the longitudinal direction. , 5
In the case of the cylindrical spring 7 which is processed so as not to reach the end surface, it can be used as a tension spring by attaching a hooking means to its end face.
Only the spring portion 13 can be used by fitting and fixing only.

Of course, as shown in FIG. 2, the cylindrical spring 19 having only the spring portion 13 without the annular support portions 15 and 17, which is the shape of a normal spring, is also processed with high precision as a spring. can do. Also, if necessary, it is possible to appropriately create a spring having an inner and outer shape.

As shown in FIG. 3, a cylindrical spring according to the present invention is used in place of a disc spring inserted into a draw bar 23 for gripping a tool in a spindle device of a machine tool, as shown in FIG. The case where the shape spring 7 is used as a cylindrical compression spring will be described.

The main shaft head 21 is provided with a hollow main shaft 29 rotatably supported by a front bearing 25 and a rear bearing 27, and the main shaft 29 is provided with a gear 31 fixed to its outer peripheral portion.
, And is rotated with respect to the spindle head 21 by being driven by a motor (not shown). A tapered hole at the lower end of the main shaft 29 is in contact with a taper shank of a tool (not shown).
A drawbar 23 is inserted into the main shaft 29, a tool grip 35 is provided at the lower end of the drawbar 23, and a tool is gripped by the tool grip 35 at the upper end of the drawbar 23. A cylindrical spring 7 for pulling up and mounting a tool in the tapered hole 33 is formed with an upper end threaded portion 23a which is screwed with a spring retainer 37 which is fitted and held on the upper outer periphery of an upper shoulder 29a of the main shaft 29. Have been. Bearing holders 25a and 27a and lock nuts are provided on the outside of the bearings 25 and 27, respectively.
25b, 27b and the spring retainer 37 are provided with a loosening stopper 37a.

On the upper side of the spindle head 21, a draw bar 23 is pressed downward against the elastic force of the cylindrical spring 7, and a tool is attached to the spindle head 21.
Unclamp cylinder 39 to remove from 29
41, the draw bar 23 is pushed down against the elastic force of the cylindrical spring 7 by the lowering of the unclamping piston 45 which is moved in the unclamping cylinder 39 by the air pressure from the air introduction port 43. The tool is configured so that the tool is unclamped from the spindle 29.

In the conventional apparatus, since a plurality of disc springs are inserted into the outer peripheral portion of the draw bar 23 instead of the cylindrical springs 7, the disc springs necessarily move with the center of gravity when the main shaft 29 rotates at high speed. On the other hand, according to the present invention, according to the present invention, the cylindrical spring 7 can be fitted into the outer peripheral portion of the main shaft 29 with high precision, so that even if the main shaft 29 rotates at high speed, the spring 7 Does not occur, and the generation of vibrations due to the movement of the center of gravity of the spring 7 can be avoided. Also,
Disc springs and drawbars without the problem of seating between disc springs
No prying occurs with 23 and a stable tool clamping force can be generated.

[0020]

According to the present invention, cutting, grinding,
By a normal machining method such as electric discharge machining, it becomes possible to easily manufacture a cylindrical spring having a highly accurate shape and dimensions such as an outer diameter, an inner diameter, a length, and an end face.

Therefore, a counterpart member (spindle or drawbar) such as a tool clamping means in a spindle device of a machine tool.
It is possible to provide a cylindrical spring applicable to a place where a high mounting accuracy is required and a place where a good balance is required at a high speed rotation.

For example, as in the embodiment shown in FIG. 3 described above, a cylindrical spring according to the present invention is used as a compression spring instead of a disc spring inserted into a draw bar for holding a tool in a spindle device of a machine tool. When used, a spindle device with less vibration is obtained.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a cylindrical spring manufactured by the manufacturing method of the present invention, wherein (a) is a top view and (b) is a side view.

2A and 2B show another embodiment of the cylindrical spring manufactured by the manufacturing method of the present invention, wherein FIG. 2A is a top view and FIG. 2B is a side view.

FIG. 3 is a cross-sectional view of a spindle device using a cylindrical spring according to an embodiment of the present invention as a compression spring for tool clamping means.

[Description of Signs] 1 end surface 3 spiral groove 5 end surface 7 cylindrical spring 9 outer peripheral surface 11 inner peripheral surface 13 spring portion 15, 17 annular support portion

Claims (6)

[Claims] 1. A cylindrical spring material suitable for spring specifications such as a desired outer diameter or inner diameter of a spring, length, wire diameter, number of turns, etc. is manufactured, and a spiral groove is formed in the cylindrical spring material. And manufacturing a spring having desired spring specifications. 2. The method for manufacturing a cylindrical spring according to claim 1, wherein the spiral groove is formed by cutting with a metal saw or an end mill. 3. The method for manufacturing a cylindrical spring according to claim 1, wherein the spiral groove is formed by electric discharge machining using a rod-shaped electrode or a wire electrode. 4. The manufacturing method according to claim 1, wherein the shape of the spring is defined by an outer diameter, an inner diameter, a length, and the number of turns, and the end face in the length direction is formed in a flat shape. Cylindrical spring manufactured with. 5. The helical groove is formed so as not to reach a longitudinal end face of the cylindrical spring material, and has an annular support portion without a spring portion at both ends of the cylindrical spring. The cylindrical spring according to claim 4. 6. The helical groove is formed so as to open at a longitudinal end face of the cylindrical spring material, and a spring portion is formed over the entire length of the cylindrical shape in the longitudinal direction. 4. A cylindrical spring according to claim 1.