JPS62296911A - Plastic working shrinking center part only - Google Patents

Abstract

PURPOSE:To work the torsion bar causing a torsion stress only without causing a bend stress by moving a roller in the axial direction of a bar stock by pressing it to the center part with rotating the metal round bar stock by pulling it as well, and shrinking the center part of the bar stock with its plastic deformation. CONSTITUTION:A metal round bar 3 is rotated with its both ends being supported by a stationary bearing 4 and mobile bearing 5, which is moved in the arrow mark direction by a hydraulic cylinder 8 and a tensile stress is acted on the bar 3. The freely rotatable rollers, 9, 10, 11 pressing from a right angles direction are arranged on the bar 3 to act a bend stress thereon. The rollers 9, 10, 11 are moved in the axial direction of the bar 3 by being guided with a feeding screw, elongated by being bent, the part to be contracted before elongated is expanded at the center part excepting its both end parts and a torsion bar is obtd.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a plastic working method that can be used to manufacture thin and long 1-jumpers and the like.

<Prior art> Thin and long torsion bars, such as round bars with a diameter of about 5.0 mm and a length of 600 mm or more, are generally manufactured using piano wire or oil tempered wire. When manufacturing the torsion bar 1 from such a wire, both ends are generally bent slightly to form an L-shape, as shown in FIG. 2, in order to apply torsional stress. However, this 5
In addition to shear stress due to torsion, a bending moment occurs in the shape of the wire, and as a result of this compounding with torsional shear stress, the high strength of piano wire and oil-tempered wire cannot be used solely for torsional stress. It is also taken away by the stress caused by bending. Therefore, it cannot be a high-performance torsion bar. In order to generate only torsional stress in the torsion bar, bulge both ends, grasp this part to apply torsional stress, and align the axis of the torsion bar with the axis when applying torsional stress to prevent the generation of bending stress. Just prevent it. For this purpose, a toshii evening bar 2 having a shape as shown in FIG. 3 is required. Piano wire and oil-tempered wire are heat-treated to achieve high strength, so if both ends are swollen by hot plastic processing, the performance of the wire, which has been tempered to high strength, will deteriorate. Become.

Therefore, we should use a material that can be heat treated to have a strength equal to or higher than that of piano wire or oil tempered wire, such as maraging steel, and then plastically work it to make both ends bulge before heat treatment, or cut the parts other than both ends. Or, after plastic working to make it thinner, heat treatment can be applied to make it stronger.

<Problems to be Solved by the Invention> In order to bulge both ends, a method of plastically bulging by cold heading, so-called header processing, can be considered.

However, if both ends are thicker and longer than the shape of the nail or bolt head, it will be difficult to inflate them by cold plastic working. Although hot plastic forging would improve the material's extensibility, it would be possible, but the central part, which is the most important part of a torsion bar, would be oxidized and would require post-processing, making it difficult to manufacture.

The next possible method is to use a wire rod with a thick shape corresponding to both ends, and to thin the wire material other than both ends by cutting. Since the cutting of the central part involves machining a long and narrow object, the workpiece bends, making the cutting process extremely difficult. Therefore, the present invention aims to provide a method for narrowing the central portion by plastic working.

Means for Solving the Problems> The structure of the present invention to achieve the above object is to pull a round metal bar material in the axial direction and rotate it while pressing a rotatable roller against the center of the bar from the right angle direction. By moving the rollers in the axial direction of the bar while applying bending stress to the bar, the central portion of the bar is plastically deformed and narrowed.

Action: Rotate a metal round bar while applying tensile stress, and in that state apply a bending stress to the bar by pressing a roller perpendicularly to the bar near one end. Then, the outer periphery bent by the roller stretches plastically, but since the bar itself rotates with tensile stress applied, the outer periphery of the material stretched by bending eventually stretches to the side pressed against the roller. It will rotate. The inside that was being pressed by the rollers rotates outward, bending and stretching it. In such a state, when applying bending stress and moving the roller in the axial direction of the bar, the narrowed part of the bar due to bending and elongation will eventually expand in the axial direction of the bar as the roller moves. Eventually, both ends of the bar will remain in their original shape, but only the center will be narrowed.

EXAMPLE Hereinafter, an example of the method of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of an apparatus used in an embodiment of the present invention. As shown in the figure, a metal round bar (hereinafter simply referred to as a bar) 3 has both ends supported by a fixed bearing 4 and a movable bearing 5, and one end of the bar 3 supported by the fixed bearing 4. It is connected to a motor 7 via a speed reducer 6, and the bar 3 is driven to rotate.

The movable bearing 5 is connected to a hydraulic cylinder 8 and is configured to move in the direction indicated by the arrow in the figure.
Tensile stress is supposed to act on it.

Further, between the fixed bearing 4 and the movable bearing 5, a rotatable roller 9 is provided which presses the bar 3 from a right angle direction. ．． 10.
11 are arranged so that bending stress is applied to the bar 3.

These rollers 9 and 10 are located above the bar 3, whereas the roller 11 is located below the bar 3. Furthermore,
These rollers 9, 10° 11 are guided by a feeder,
It is movable in the axial direction of the bar 3. Therefore, the bar 3 is bent and elongated by the rollers 9, 10, 11, and the narrowed part eventually expands to the center part other than both ends, resulting in a 1-symbar as shown in Fig. 3. It will be done.

Of course, by repeating the axial movement of the rollers 9, 10, 11 that apply bending stress many times, the bar 3 can be made thinner. Moreover, if the bar material 3 undergoes cold hardening and becomes difficult to plastically work, it is possible to obtain a considerably thin round piece by annealing it if necessary and then plastically working it according to the present invention. .

In order to eliminate distortion of the L-version version 2 formed in this manner, tensile stress may be applied after forming to make it straight. Next, in the case of maraging steel, a predetermined strength can be imparted by subjecting it to aging treatment. The gripping portions at both ends may be finished by cutting after molding or heat treatment. Incidentally, the bar of the present invention also includes a wire.

<Effects of the Invention> As explained above in detail based on the examples, the present invention thins only the central part of the bar by plastic working,
It should be possible to process torsion bars that generate only torsional stress without bending stress.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a device used in an embodiment of the present invention, and FIGS. 2 and 3 are front views each showing a torsion bar. 1.2 is 1-Johnper 3 is a bar, 4 is a fixed bearing, 5 is a moving bearing, 6 is a reducer, 7 is a motor, 8 is a hydraulic sill, 9.1.0.11 is a roller, 12; It is the feed screw shaft. Patent applicant Mitsubishi Heavy Industries Co., Ltd. Agent

Claims (1)

[Claims] While pulling the metal round bar in the axial direction and rotating it, a rotatable roller is pressed against the center of the bar from a right angle direction, and while applying bending stress to the bar, the roller is moved in the axial direction of the bar. A plastic working method characterized by plastically deforming and narrowing the central part of the bar by moving it.