JPH03199729A - Belleville spring - Google Patents

Abstract

PURPOSE:To form a pressure/displacement curve in a large gradient and into linear shape at the time of starting pressurization by setting a number of revolving turns of a spiral wave pattern to three times or more and further forming a slope in the radial direction of the spiral wave pattern in outside recessed shape. CONSTITUTION:In the case of a belleville spring D formed by tilting its spiral wave pattern P, which is presented as a waveform section from an arbitrary peripheral point in the periphery of a material plate center circle 10, to the center circle 10, the spiral wave pattern P is formed with a number of its revolving turns set to at least three times, and further a slope in the radial direction of the spiral wave pattern P is formed in outside recessed shape while setting ratio h/l of slope height (h) to length l in the diametric direction, of the spiral wave pattern P, to 1/5 or less. In this belleville spring D, deflection by pressing force is transmitted to the total area through the spiral wave pattern P with no unevenness in generated stress, and the spring is uniformly deflected in the peripheral direction without tilting the center axis. Now because of the total length of the spiral wave pattern P increased larger, rigidity is decreased, and a pressure/displacement curve is formed in linear shape, at the time of starting pressurization as well as, a large gradient of the curve is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a disc spring that can be deflected uniformly over the entire circumference, and is mainly made of a steel plate suitable as a diaphragm or a spring for returning the key top of a keyboard switch. , concerning disc springs made of stainless steel plates, rubber plates, and plastic plates.

[Conventional technology and its problems]

As shown in FIG. 9, conventional disc 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 disk spring, but is first transmitted to the innermost ripple P and is deflected between them.When the deflection reaches a certain level, the ripple P The deformation is propagated in stages such that the ripple P reaches 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 inventors of the present invention have created spiral ripples that start from at least two points equidistant in the circumferential direction around the center circle 10 of the material board, as shown in FIG. We proposed a disc spring D with a corrugated cross section exhibiting P. In this proposed disc spring D, since the waveform P is spiral, the rigidity of the surrounding area is made uniform, and when the spring is deflected, it is deflected uniformly in the circumferential direction without any bias in stress.

However, as shown in Fig. 4, the pressure-displacement curve (○: during pressurization, .: during depressurization, see comparative example (broken line)) lacks linearity, and is not smooth, especially at the start of pressurization.
Some diaphragm sensors, in which this type of disc spring is often used, require linearity at the start of pressurization.

Additionally, users have requested a device that can obtain a large displacement with very low 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 disc 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 center circle 10 is to prevent the center axis from tilting when the disc spring D is bent. However, even if there is only one spiral ripple P, if the number of circumferences increases, the central ring will not tilt (it will tilt only to a negligible extent)
I found out that.

The present invention takes the above points into consideration, and aims to increase the gradient of the pressure-displacement curve of the spiral ripple disc spring, and to make the pressure-displacement curve linear at the start of pressurization.

[Means to solve the problem]

In order to solve the above problems, in the present invention, based on the above knowledge, in the disc spring with a wave-shaped cross section exhibiting the spiral ripples, the number of revolutions of the spiral ripples is three or more times, and ? The radial inclination of the II-wound ripples is concave to the outside.

A single f4 winding ripple may be sufficient, or in the case of multiple ripples,
Each starting point is an equal quantile around the central circle.

Concentric circular ripples are formed adjacent to the center circle of the material plate, outer circular ripples are formed concentrically with the concentric circular ripples at a predetermined interval, and the spiral ripples are formed between the dual-purpose ripples. It can also be assumed that

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

[Effect]

When a pressure force, such as compressed air pressure, is applied to the surface of a disc spring constructed in this way, the deflection due to the pressure force is transmitted to the entire area via spiral ripples, and the generated stress is not biased and is centered. During this bending, when the axis is deflected uniformly in the circumferential direction without inclination, the total length of the spiral ripples is longer, so the rigidity is lower than that of conventional ones, that is, the degree of deflection is also large. Therefore, the pressure-displacement curve has a large slope and is linear at the start of pressurization (see Examples).

In addition, if concentric circular ripples and outer circular ripples are provided, when the ripples are in the press acid form, the raised distortion that occurs in the center will be absorbed and dispersed by 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 by ripples. This absorption and dispersion becomes even more effective if the beginning and end of the spiral ripple merge into the dual-use ripple.

Therefore, if the above disc spring is used in a diaphragm or diaphragm type pressure detection device, since the disc 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 disc spring described above 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 be possible to transmit not only the vertical component force but also the horizontal component force. It has a smooth bending action and is easy to operate.

〔Example〕

In this example, a disc spring is used as a diaphragm, and the material used has a thickness of 0. A hoop made of stainless steel foil with an OL of 5 mm and a diameter of 34 wheels was pressed to have a finished outer diameter of 25.4 ml.

This embodiment is shown in FIGS. 1 and 2, in which the pitch d of the spiral ripple P is 0.598 mm, the diameter of the center circle 10 is S-5,01, and the outermost diameter of the ripple P is -20, 2m
m, curvature of valley and peak r = 0.3 m, height of ripple P t = 0.08 m, height difference between outer periphery and center T = 1.2
The curvature R of the ripple P part was set to 100 mm, and the center of the curvature R was set to the outside, and the spiral ripple P was shaped around 12 times from the point around the central circle 10 (the first
Waves are omitted in Figures 2 and 2).

On the other hand, as a comparative example, the spiral ripple P shown in FIG. We also manufactured one in which the slope is outwardly convex. At this time, dS
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. 5 and 6, and the respective pressure-displacement results are shown in FIGS. Dashed line (
A) shows a comparative example.

From the results shown in Figure 3, it can be seen that the example has a higher
It can be seen that the slope is steep (large). That is, the example can obtain a larger displacement with a lower pressure than the comparative example. Note that no inclination of the central axis occurred on both sides.

Moreover, from the results shown in FIG. 4, it can be seen that the example exhibits a nearly linear pressure-displacement at the start of pressurization (θ~700 mAg).

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, the measuring device A includes a disc spring D of an embodiment or a comparative example inserted into a casing 4 through a banking 5, compressed air is introduced from a port 6, and the introduced pressure causes a disc spring D to be inserted into the casing 4 through a banking 5. In Figure 0, reference numeral 8 is a transparent acrylic plate, through which the deflection action of the disc spring D can be seen.

In the above embodiment, as shown in FIG.
A concentric circular ripple P+ is formed adjacent to 0, and an outer circular ripple P2 is formed concentrically with this concentric circular ripple P and at a predetermined interval, and eye-shaped ripples p, , Pg are formed.
A similar effect was obtained by manufacturing a structure in which the spiral ripples P were formed in the same circumferential shape as in the above embodiment. In this case, the inner circular ripple P1 can also be omitted.

Furthermore, in the case shown in FIG. 8, a similar effect was obtained when each spiral ripple P was made to rotate three times or more.

In this structure, the outer circular ripples P can be formed, and each spiral ripple P can be added to the ripples P□.

The degree of inclination of the spiral ripples P, P, that is, the ratio of the inclination height h to the radial length l in FIG. 2 (hlo
is preferably 115 or less, preferably 1/6.

This is because if it exceeds 115, the molding pressure for the outwardly facing slope and the inwardly facing slope will be significantly different, making it impossible to manufacture with the current technology when pressing the bottom shape.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to obtain a large displacement (deflection) with a small pressure compared to the conventional one, and it is also possible to make the pressure-displacement curve at the start of pressurization linear.

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 7 are schematic front views of each embodiment of the disc spring according to the present invention, FIG. 2 is a sectional view of the embodiment of FIG. 1, and FIG.
Fig. 4 is a pressure-displacement measurement diagram, Fig. 5 is a schematic diagram of the pressure-displacement measuring device, Fig. 6 is a sectional view of the main part of Fig. 5, and Figs. 8 and 9 are schematic front views of the conventional example. It is a diagram. 10...Central circle, P, P, , pg・
...Circular ripples, A...Pressure-displacement measuring device, D...Disc spring. P... spiral ripples,

Claims (1)

Scope of Claims: (1) A wavy cross section exhibiting spiral ripples P from any point around the center circle 10 of the material plate, and the spiral ripples P are inclined to the center circle 10 in a disc spring. . A disc spring characterized in that the spiral ripples P are formed around at least three times, and the spiral ripples P have an outwardly concave inclination in the radial direction. (2) A disc spring D according to claim (1), characterized in that the spiral ripple P is formed as a single strip. (3) The disc spring D according to claim (1), characterized in that 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 disc 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 disc 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. (5) Incline height h and radial length l of the spiral ripple P
The disc spring according to any one of claims (1) to (4), characterized in that the ratio h/l is 1/5 or less.