JPH03199728A - Leaf spring - Google Patents

Abstract

PURPOSE:To obtain a pressure/displacement curve with a large plope by forming a spiral wave pattern with its number of turns set to three times or more, in the case of a leaf spring of waveform section for presenting the spiral wave pattern. CONSTITUTION:In the case of a leaf spring D, a spiral wave pattern P is presented as a waveform section in the periphery of a material plate center circle 10 from its arbitrary point, and the spiral wave pattern P of the leaf spring is provided with a single streak with at least three circumferential turns formed. When pressing force is applied to a surface of this leaf spring D, deflection by the pressing force is transmitted to a total area through the spiral wave pattern with no deviation in generated stress, and the spring D is deflected uniformly in the peripheral direction without tilting a center axis. Since a total length of the spiral wave pattern is increased larger at the time of this deflection, a degree of deflection is increased also with less rigidity as compared with the spring in the past. Therefore, a pressure/displacement curve is obtained in a large gradient.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a temporary spring capable of uniformly deforming over the entire circumference. , concerning leaf springs made of stainless steel plates, rubber plates, and plastic plates.

[Conventional technology and its problems]

As shown in FIG. 8, conventional leaf springs for diaphragms have a wavy cross-sectional shape that exhibits concentric ripples P around the center circle 10 of the material plate.
(see figure), and the ripples P in the figure indicate the locus of the trough (the same applies hereinafter).

However, in this case D, the rigidity is high because the peripheral fixing part is subjected to brazing, etc., and the central part also has a small radius of curvature, so the rigidity is high.

Therefore, if the deflection is small at the periphery and the center, and the deflection is concentrated in the middle, if the material plate is made of metal, buckling or cranking may occur due to metal fatigue, and the characteristics may change over a long period of use. There are problems such as changes in resilience.

In addition, in the deflection (deformation) action, the pressing force applied to the center circle 10 is not transmitted to the entire area of the disc spring, but is first transmitted to the innermost ripple P and is deflected between them, and when the deflection reaches a certain level, the ripple P The deformation is propagated in stages such as exceeding the ripple P and reaching the next ripple P. Therefore, when the deflection exceeds the ripple P, a disturbance occurs in the displacement curve.

Therefore, in Japanese Patent Application No. 63-99143, etc., the present inventors proposed that, as shown in FIG. We have proposed a leaf spring D with a corrugated cross section that exhibits. In this proposed leaf spring D, since the waveform P is spiral, the surrounding rigidity is made uniform, and when the leaf spring D is bent, the stress is not biased and the spring is bent evenly in the circumferential direction.

However, users have requested a device that can obtain a large displacement with a very small pressure, that is, a device with a large slope of the pressure-displacement curve.

In order to meet this demand, the inventors of the present invention considered that the way to increase the slope of the pressure-displacement curve is to reduce the rigidity of the entire leaf spring. For this reason, first, it was found that the longer the total length of the spiral ripples P of the -stripe, the lower the rigidity.

Further, the reason why the spiral ripples P are started from at least two points equally spaced around the central circle 10 is to prevent the central axis from tilting when the leaf spring D is bent. However, even if there is only one spiral ripple P, if the number of circumferences increases, the central axis will not tilt (the tilt will only be negligible)
I found out that.

The present invention takes the above points into consideration, and an object of the present invention is to increase the slope of the pressure-displacement curve of the spiral ripple leaf spring.

[Means to solve the problem]

In order to solve the above problems, in the present invention, based on the above findings, in the leaf spring having a wave-shaped cross section exhibiting the above-mentioned spiral ripples, the number of revolutions of the spiral ripples is set to 3 or more. A single spiral ripple may be used, or in the case of multiple ripples, the starting points of each ripple are equally spaced around the central circle.

Concentric circular ripples are formed adjacent to the center circle of the material board, and outer circular ripples are formed concentrically with the concentric circular ripples at a predetermined interval, and the spiral ripples are formed between the two circular ripples. It is also possible to form one.

If the number of turns of the spiral ripples is three or more, the central axis will not be tilted when the leaf spring is bent, and the number of turns of the spiral ripples is preferably five or more.

(Function) When a pressing force, such as compressed air pressure, is applied to the surface of a leaf spring configured in this way, the deflection due to the pressing force is transmitted to the entire area via spiral ripples, and the stress generated is biased. During this bending, the total length of the spiral ripples is longer, so the rigidity is lower than the conventional one, and the degree of bending is also large. The slope of the pressure-displacement curve will be large.

In addition, if concentric circular ripples and outer circular ripples are provided, when the ripples are press-formed, the raised distortion that occurs in the center will be absorbed and dispersed in the concentric circular ripples, and the linear distortion that occurs on the outer periphery will be absorbed and dispersed in the outer circular ripples. absorbed and dispersed. This absorption and dispersion becomes more effective if the beginning and end of the spiral ripples merge into the hundred circular ripples.

Therefore, if the above leaf spring is used in a diaphragm or diaphragm type pressure detection device, since the temporary spring has the above characteristics, it will have constant characteristics (restoring force) over a long period of time and will have high reliability. .

In addition, if the above leaf spring is used as a spring for returning the key top of a keyboard switch, the pressing force will be transmitted to the entire area via ripples due to the above characteristics, so it will not be deflected not only by the vertical component force but also by the horizontal component force. , it has a smooth bending action and is easy to operate.

〔Example〕

In this example, a leaf spring is used as a diaphragm, and the materials used are stainless steel foil with a thickness of 0.015 cm, and a hoop with a diameter of 341 mm, which is pressed to have a finished outer diameter of 25.4 mm. This is what I did.

This embodiment is shown in FIGS. 1 and 2, in which the pitch d of the spiral ripple P is 0.598 m, and the center circle is 1.
Diameter of 0 S - 5, 0, outermost diameter of ripple P = 20.2, curvature of valleys and peaks r - 0, 3, height of ripple P t = 0
．． 08m, the difference in height between the outer periphery and the center T = 1.2m, the curvature R of the ripple P part = 100m, and the spiral ripples P were shaped around 12 times from the periphery of the center circle 10 (second
Waves are omitted from the figure).

On the other hand, as a comparative example, a spiral ripple P shown in FIG. 7 was formed from three equal parts of the central circle 10, and the number of revolutions was more than one. At this time, d, s, r, t,
``r, R, etc. were all the same.

The above examples and comparative examples were set in the pressure-displacement measuring device shown in FIGS. 4 and 5, and the respective pressure-displacement results are shown in FIG. shows.

From this result, it can be seen that the slope of the example is steeper (larger) than that of the comparative example. That is,
In the example, a larger displacement can be obtained with a lower pressure than in the comparative example. Note that no inclination of the central axis occurred on both sides.

As shown in FIG.
The measuring device A shown in the figure was bolted to the base 1, and the amount of vertical movement of the displacement rod 2 was detected by a well-known optical sensor 3. As shown in FIG. 5, in the measuring device A, a leaf spring D of the example or comparative example is set in a casing 4 via a backing 5, compressed air is introduced from a boat 6, and the introduced pressure causes the leaf spring to In Figure 0, reference numeral 8 is a transparent acrylic plate through which the deflecting action of the leaf spring D can be seen.

In the above embodiment, as shown in FIG.
A concentric circular ripple P1 is formed adjacent to 0, and an outer circular ripple Pt is formed concentrically with the concentric circular ripple P1 at a predetermined interval, and a spiral ripple P is formed between the hundred circular ripple P+ and Pg. , which had the same circumferential shape as that of the previous embodiment, was manufactured, and the same effect was obtained. In this case, the inner circular ripple P can also be omitted.

Furthermore, in the case shown in FIG. 7, the same effect was obtained when each spiral ripple P was made to rotate three times or more.

In this structure, the outer circular ripple P2 may be formed, and each spiral ripple P may be added to the ripple P2.

Incidentally, the inclination of the spiral ripples P and Pg, that is, the ratio of the inclination height h to the radial length l in FIG. 2 (h/l
) is preferably 175 or less, preferably 1/6. If it exceeds 115, the molding pressure will be significantly different between the outward slope and the inward slope during press molding, making production impossible.

〔Effect of the invention〕

Since the present invention is constructed as described above, it is possible to obtain a large displacement (f1!) with a small pressure compared to the conventional one.

In addition, if the spiral ripples are formed in one line, it is easier to manufacture them than if they are formed in multiple lines.

[Brief explanation of drawings]

1 and 6 are schematic front views of each embodiment of the leaf spring according to the present invention, FIG. 2 is a sectional view of the embodiment of FIG. 1, FIG. 3 is a pressure-displacement measurement diagram, and FIG. The figure is a schematic diagram of a pressure-displacement measuring device, FIG. 5 is a sectional view of a main part of FIG. 4, and FIGS. 7 and 8 are schematic front views of a conventional example. 10...Central circle, P, P3...
Spiral ripples, P,, P□...Circular ripples, A...Pressure-displacement measuring device, D...Plate spring

Claims (3)

[Claims] (1) A leaf spring having a wave-shaped cross section that exhibits spiral ripples P from arbitrary points around the central circle 10 of the material plate, and the spiral ripples P are formed around at least three circumferences. (2) A leaf spring D according to claim (1), characterized in that the spiral ripples P are formed as a single strip. (3) The leaf spring D according to claim (1), wherein the spiral ripples P are plural, and the starting point of each spiral ripple P is equally spaced around the central circle 10. Spring. (4) In the leaf spring D according to claim (1), concentric circular ripples P_1 are formed adjacently around the center circle 10 of the material plate, and the concentric circular ripples P_1
A leaf spring characterized in that outer circular ripples P_2 are formed concentrically with and spaced apart from each other at a predetermined interval, and the spiral ripple P_3 is formed between both circular ripples P_1 and P_2.