JPH08145100A - Spring - Google Patents

Abstract

PURPOSE: To provide a flat spring which can impart large resiliency and displacement. CONSTITUTION: A frame-shaped spring 1 is made by bending a strip material in the same plane. The spring 1 has a U-shaped stress absorbing part 5 which is formed by reversely bending back an extending part from a longitudinal part 4 at the one end of the above part 4 and connecting it to a lateral part 2. When load W is added at a working point B, bending stress acting at the bent corner of the end of the lateral part 2 is eased by the smooth elastic deformation of the stress absorbing part 5. Thus, residual deformation at the above corner can be restrained to be small, and since its whole structure is frame- shaped, large repulsive force can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to small equipment and parts requiring a small repulsion mechanism that can be accommodated in a flat space.
The present invention relates to a spring used as a repulsive force generation source.

[0002]

2. Description of the Related Art Usually, when a repulsion mechanism using a spring requires a relatively large repulsive force and displacement, a coil spring or a bamboo spring is often used.

When it is not possible to secure a sufficient spring storage space in the height direction, a spring as shown in FIG. 3 in which a spring steel wire is bent zigzag in the same plane may be used.

[0004]

SUMMARY OF THE INVENTION For example, in a connector of a type in which an elastically deformable lock arm is engaged with a check claw at the end of fitting to maintain a connected state, the reliability of the fitting operation is improved. As shown in Japanese Patent Application Laid-Open No. 4-306575, a repulsion mechanism incorporating a spring is provided,
The force of the spring compressed when the male and female connectors are inserted pushes back the connector with the poor fitting to the position where the spring is fully extended. If the spring of the repulsion mechanism used for such an application is a coil spring as disclosed in the above publication, it will take up a large storage space and cause the size of the connector and the like to increase.

Therefore, a flat spring as shown in FIG. 3 is required. However, with this zigzag spring, it is difficult to obtain a large spring constant, and it is difficult to reliably push back an object, such as a connector.

In the zigzag spring, when the wire rod has a uniform cross section, when the load W is applied, the maximum bending stress concentrates on the elastically deformed portion (the portion A in the figure) farthest from the point of action B, and a small load is applied. Would exceed the yield point of the wire. Therefore, it cannot be used in a repulsion mechanism that requires a large force, and its application is narrow.

In order to disperse the maximum bending stress,
A rectangular spring as shown in Fig. 4 is also conceivable, but with this shape, bending stress concentrates at the crossing corners of the horizontal and vertical directions of the wire, and the residual deformation of this part increases, so the displacement (= If the amount of compression is increased, it will be difficult to push the object back to its original position.

Therefore, the present invention makes use of the advantages of a rectangular spring that can be made thin and has a large spring constant, while eliminating the drawbacks of this rectangular spring (the residual deformation of the corner portion becomes large) and providing a large repulsive force. An object is to provide a spring that can obtain displacement.

[0009]

A spring of the present invention for solving the above-mentioned problems is a spring made by bending a strip into a symmetrical frame shape in the same plane, one of which is a fulcrum and the other is a fulcrum. Has parallelly arranged laterally extending portions where the force acts, and left and right longitudinally extending portions provided between the laterally extending portions, and at least one end side of the longitudinally extending portion extends from the longitudinally extending portion. Is provided with a U-shaped stress absorbing portion that is bent back in the opposite direction and is connected to the laterally extending portion.

[0010]

In the spring of the present invention, a U-shaped stress absorbing portion is added to the corner portion of the rectangular spring. Further, in this spring, when a compressive load is applied to the laterally extending portion, the U-shaped stress absorbing portion is naturally elastically deformed and narrowed, whereby the bending stress acting on the end portion of the laterally extending portion is relaxed. Therefore, stress does not concentrate on the bending corners at both ends of the laterally extending portion, and the residual deformation of the corner due to excessive stress can be suppressed to a small level. Therefore, a larger repulsive force than the spring of FIG. 3 and a larger displacement than the spring of FIG. 4 can be obtained together.

[0011]

FIG. 1 shows an example of the spring of the present invention. This spring 1 is made by bending a raw material in the same plane so that one end is a starting point and the other end is returned near the starting point. Longitudinally extending portions 4 and 4 on both sides of the longitudinally extending portion 4 and the U-shaped stress absorbing portions 5 and 5 in which the extending portions from the respective longitudinally extending portions 4 are bent back in the opposite direction and connected to the laterally extending portion 2.
Is symmetrically arranged.

The strip material is preferably made of spring steel from the viewpoint of repulsive force, but other metal or resin used as a spring material, or a composite material of a resin and a reinforcing filament can also be used.

The strip is preferably a wire in view of the storage space of the spring, but may be a strip unless the width is extremely wide.

Further, in the spring 1 shown in FIG. 1, the stress absorbing portion 5 is provided at the corner portion on the side far away from the side portion 3 as the point of action B of the force, but as shown in FIG. A similar stress absorbing portion 5 is also provided at the corner portion on the opposite side of the longitudinally extending portions 4, 4.
May be provided.

In addition, in the illustrated spring, one end and the other end of the strip are arranged at an intermediate portion of the laterally extending portion 2, and this portion is supported by the reaction force receiving member 10 to form a fulcrum A. . Therefore, it is not necessary to connect the one end and the other end of the strip, but if the one end and the other end are connected by welding or the like, the positional relationship between the fulcrum A and the point of action B of the force is reversed from the figure. You can also use it.

The results of the characteristic evaluation test of the spring of the present invention are shown below.

The test was carried out by using the same spring steel wire to make springs having the same external dimensions as shown in FIGS. 1, 2, 3 and 4 and applying a spring constant and a constant displacement (10 mm). The residual deformation was investigated and compared.

The results are shown in Table 1.

[0019]

[Table 1]

From this result, it is understood that the spring of the present invention can obtain a large spring constant and a large displacement.

[0021]

As described above, according to the spring of the present invention, the strip material is bent into a frame shape in the same plane, and the stress absorbing portion is present at the corners. It can be made thinner than the bamboo shoot spring, can have a spring constant several times larger than that of the zigzag spring, and can have a much larger displacement (compression amount) than the rectangular spring.

Therefore, if this spring is used, the compact repulsion mechanism can be further miniaturized and the reliability can be improved, the use restriction of the repulsion mechanism due to lack of space can be relaxed, and the equipment and parts incorporating the repulsion mechanism can be further improved. It can contribute to miniaturization.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a spring of the present invention.

FIG. 2 is a plan view of another embodiment.

FIG. 3 is a plan view of a zigzag spring.

FIG. 4 is a plan view of a rectangular spring.

[Explanation of symbols]

 1 Spring 2, 3 Horizontal going part 4 Vertical going part 5 Stress absorbing part 10 Reaction force receiving member A fulcrum B Force acting point

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuru Ito 1-14 Nishisuehiro-cho, Yokkaichi-shi In Sumitomo Wiring Systems Co., Ltd. 72) Inventor Shoji Suzuki 1-14 Nishisuehiro-cho, Yokkaichi-shi Sumitomo Wiring Systems Co., Ltd.

Claims (1)

[Claims] 1. A spring, which is made by bending a strip into a frame shape of left-right symmetry in the same plane, in which one side is a fulcrum and the other side is a parallel arrangement laterally extending portion, There is a left and right vertical direction portion provided between the horizontal direction portions, and further, at least one end side of the vertical direction portion, the extending portion from the vertical direction portion is bent back in the opposite direction and connected to the horizontal direction portion U. A spring having a character-shaped stress absorbing portion.