JPS59174227A - Manufacture of spiral spring - Google Patents

Abstract

PURPOSE:To prevent occurrence of deformation and torsion in a spring after forming in manufacturing a spring from a steel material by performing shot peening on both surfaces of the material at a specified place of the manufacturing step. CONSTITUTION:When manufacturing a spring from a steel material, (1) shot peening is performed on both surfaces of the material during cold rolling the spring material. Or, (2) after cold rolling and before the material is slit to a specified width, trimmed and bent, shot peening is performed. Or, (3) shot peening is performed after forming and before aging and presetting. By these processings, residual stress can be given to the material, and occurrence of deformation and torsion in the spring after forming can be prevented.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a mainspring spring.

In order to increase the fatigue strength of springs, shots (steel grains) are injected onto the surface of the copper phase.This is a method called shot peening. Niyotobininking is carried out in the final process after spring forming (・ru. Or it is carried out only on one side of the spring forming product ~・
Ru.

By the way, the spring (spring) has gone through the rolling process, for example 0.
The mainspring is manufactured by bending and forming it into a spring using a thin plate of 13m. As a result, it was found that compressive residual stress was applied to the surface layer of the copper material, increasing its fatigue strength.
It has also been found that when shot peening is applied to one surface of a ln spring after molding, the product becomes deformed or twisted, and the curvature changes, causing dust particles that are not desirable for spring products.

When compression residual hardening is applied to a product that has undergone a rolling process, slitting process, and edge processing (land processing) process, it becomes shot peening. It turns out there is a problem.

The present invention was completed as a result of intensive studies in view of the above circumstances.
To provide a method for manufacturing a mainspring spring that is manufactured using a thin sheet of wood, which can be made from bamboo, by imparting compressive residual stress to reduce fatigue life, and which can also eliminate the above-mentioned problems. It was very successful.

The method for manufacturing the spring of the present invention will be described in detail below.

Figure 1 shows an example of the process sheet for turning the OL, the mainspring, and the spring.

Stainless steel, copper, etc., are prepared by cold rolling to form a copper plate, then polishing the surface of the copper plate as necessary, stringing it to a certain width, Edges are rounded (Run I processing), bent (formed), aged (e.g. 400" C heat treated for 2 hours), and then once the diameter is set to a predetermined diameter in order to avoid variations in the finished diameter. Presetting is performed to expand a spring formed to a smaller diameter to a predetermined diameter.

In FIG. 1, blocks 1, 2, and 3 are blocks 1, 2, and 3 for explaining the method of the present invention in which both surfaces of the material are peened.

According to the present invention, shot peening is performed at the stage shown in block 1, i.e., during the cold rolling process before the mainspring spring forming, or at the stage shown in block 2, i.e., during the cold rolling process before the mainspring spring forming. By performing shot peening 2 later, negative residual stress (
It is possible to apply compressive residual stress (compressive residual stress), and the mainspring after molding does not lose its shape or twist, which occurs when shot peening is applied, and the curvature Δ does not change. (・.Also, conventionally, shot peening was performed in a separate process after molding, but since shot peening is performed at the material stage, it can be done continuously and throughout the manufacturing process up to the final product.) .

- Force block 3 is used in the present invention when shot peening is applied after forming.In the present invention, even when shot peening is applied after forming However, if shot peening is applied only to one side, pressure is applied to the molded material from only one direction, resulting in 1" stiffness, which inevitably causes the odor of deformation. On the other hand, by performing shot peening on both sides as in the method of the present invention, it is possible to apply pressure evenly from both sides, so this problem can be solved.

Therefore, in the material process shown in blocks 1 and 2, it is extremely effective to omit shot peening on both surfaces of the material.

As described above, the present invention avoids the adverse effects of shot peening, and therefore provides an extremely advantageous method for springs using thin plates that does not shift in shape.

In the present invention, shot peening may be carried out according to the method of the present invention during the material process or after the molding process (others may be carried out according to known methods).

However, in the present invention, when the aging treatment is performed on a spring, it is preferable to carry out the aging treatment at a low temperature, for example, about 200°C.

FIG. 2 is a side view illustrating the forming process shown in FIG. A copper strip is brought into contact with the bending part 9, and the mainspring spring 1 is bent.
Get 0.

In addition to the cast iron chill shot, various shot methods such as steel grain shot, canted wire shot, and marten shot can be used as the shot in the present invention.

In the bending trap described above, when the bending diameter is kept constant, it becomes a constant torque spring, and when the bending member 9 is slid left and right to apply a change in torque, it can be used as a variable torque spring.

Although a mainspring spring can be obtained through this process, it has become clear through intensive studies by the inventors that it is better to further preset the spring.

FIG. 6 is a diagram illustrating this presetting process, in which a mainspring spring 10 having a diameter smaller than a predetermined diameter is wound around a support drum 11, and then
The winding haiku is (reverse winding 9, the mainspring is thick with a specified diameter)
By doing so, it is possible to prevent variations in the finish of the diameter and to prevent the occurrence of stiffness or damage to the spring product. The absolute value of the compressive residual stress on the tensile side surface of can be even thicker than the absolute value of the compressive residual stress on the tensile side surface.

In the present invention, the above-mentioned method may be used to perform the spring forming process (or, it is preferable to perform the above-mentioned yacht peening Z on both surfaces of the material in combination with the following method at the same time).

That is, as shown in FIG. 4, the steel strip 4, which has been subjected to horizontal heating during the material process, is subjected to backward tension by the bank tension device 13, and forward tension is applied by the drawer device [14]. 15, the copper strip 4 is tightened. According to this method, compressive residual stress is generated by Nyoyo peening, and by tightening while applying tension from two directions, compressive residual stress is further generated on the tensile side surface during use of the spring. Therefore, the absolute value of the compressive residual stress in the mainspring spring can be further increased.

In addition, Figures 5 to 7 show a few examples of how the mainspring spring (and the torque change) is applied, and the mainspring spring is smaller than the specified diameter obtained in Fig. 4. With the embodiments shown in FIGS. 5 to 7, the mainspring that provides a torque change and expands to a predetermined diameter and has a long fatigue life can be suitably used as a winding spring used in, for example, an automobile seat belt winding device. Variable torque spring can be obtained.

In the embodiment shown in FIG. 5, the copper strip (constant torque spring spring) 4 passes through feed rollers 16, 16, guides 17, 17i, and contacts the abutment die 18, and the kite 17 and the abutment die 18 are brought into contact with each other.
A mode is shown in which a mainspring spring 100 is obtained by changing the distance by 11 mLY, applying a torque change, and bending it to a predetermined diameter.

The sixth case is the same as that shown in Fig. 5, or the angle θ of the abutment die 18 with respect to the traveling direction of the steel strip 4 is changed to impart a torque change to the copper strip, and at the same time, the bending process is performed to create a variable torque mainspring. An embodiment is shown in which the spring 100 is installed.

FIG. 7 shows a mode of imparting a torque change by reversely bending the copper strip with a 10) direction roll,
In FIG. 7, by changing the position of the medium-heated roll 21 of the setting roll 22, which is exemplified by three rolls 19°20.21, as shown by the dotted line, the amount of reverse bending is changed and a torque change is applied. It is possible to do ``3-.'' In Fig. 7, 26 is a bank tension device, 15 is a ladder section (
24 is a direction changing roll, and 25 is a tension roll.

Next, the present invention will be explained using Example 2.

The fatigue life test for the following materials was conducted in the following manner. That is, a mainspring spring is wound around a support drum of φ60,
This is further wound around an output drum having a diameter of 50 mm, and the wound material 2 is then wound back onto the support drum, and the number of times a crack occurs in the drum is determined by repeating these winding and unwinding steps. There are two ways to perform this test: one is a unit test, and the other is a barrel test carried out by storing the barrel in a casing.11. The measured values in the following items are values based on Kobako cents.

Reference example degree 0.13FIA, 6 passes, R=cl=7.0%
A variable torque mainspring with a diameter of φ12 to 16 is made by slinting a cold-rolled stainless steel plate into a 2-width and 14-inch piece, and then applying green sintering to the resulting copper strip. Through the forming process shown in Figure 2, a variable torque mainspring with a diameter of φ12 to 16 After aging at 400°C for 2 hours, it is wound around a support drum of φ60 as shown in Fig. 3, and this is further wound around a setting drum of φ27 and enlarged to a predetermined diameter of φ14 to 16 to generate a variable torque. The mainspring? @1ko.

A fatigue test was conducted on the obtained mainspring spring, and the fatigue life was 50,000 times, and the residual stress of the spring product was +
There was one at 9f/M2 on 30th.

Comparative Example 1 The mainspring spring obtained in the above reference example was shot with 0.151 mm of steel grains on one side and subjected to short heating, and the residual stress of the spring product was 170 kl.
f/Ion 2, and the fatigue life improved to 110,000 cycles, but there was one crack in the shape of the spring product.

Example 1 The cold-rolled stainless steel sheet obtained in Reference Example was treated in the same manner as Comparative Example 1, except that both surfaces were peened and aged at 7200°C for 2 hours, resulting in a residual stress of -40 kgf/ rE12, fatigue test result is 1
After 20,000 cycles, the shape after molding was good (no misalignment), and no denting occurred during use of the product.

Example 2 A mainspring spring was obtained in the same manner as in Example 1 except that shot peening 2 was performed at the same time as cold rolling. It was times. In addition, the shape after molding was not misaligned, and no denting occurred during splashing.

Example 3 A spring product was obtained in the same manner as Comparative Example 1, except that both surfaces of the spring were subjected to shot peening after forming.The residual stress of the spring was -70kpf,/rttv.
b2, the fatigue life is 110,000 times, and the shape of the shape during molding (
There was no misalignment or denting during use of the spring.

The above results are summarized in Table 1.

[Brief explanation of the drawing]

Fig. 1 is a flow sheet showing an example of the spring spring manufacturing process, Fig. 2 is an explanatory drawing of the forming process, Fig. 6 is an explanatory drawing of the presetting process, and Figs. FIG. 4 is a side view of the main part showing an embodiment of the present invention, and FIG.
FIG. 7 is a side view illustrating a mechanism for applying torque change to the spring spring. Figure 1 Figure 3

Claims (1)

[Claims] In a method of manufacturing a spring (spring) using a thin plate,
7. A method for manufacturing a senmai fly, which includes subjecting both sides of the feather to shot peening in at least the - stages of the following (1), (2), and (2). ■ Intermediate process of cold rolling before mainspring/spring forming ■ After cold rolling before spring/spring forming ■ After mainspring spring forming