JPH03200031A - Pressure sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure sensor, and particularly relates to a pressure sensor with small hysteresis during boosting pressure.

[Conventional technology and its problems]

The diaphragm type pressure sensor will be described with reference to FIG. 1. The inside of a casing 1 is divided into a pressure receiving chamber 2 and a blow-up chamber 3 by a diaphragm D, and an introduction pipe 4 for the pressure-detected fluid a is inserted into the pressure receiving chamber 2. The backup chamber 3 is provided with a ram 5 that contacts the center of the diaphragm D and is movable in the axial direction thereof, and a spring 6 that biases the ram toward the diaphragm D side. , the deflection of the diaphragm D due to the introduction pressure of the fluid a is converted into movement of the ram 5, and the amount of movement is detected by a differential transformer, optical sensor, laser sensor, etc.

As the diaphragm D of this pressure sensor, the inventors of the present application disclosed in Japanese Patent Application No. 63-99143, etc.
As shown in Figures 3 and 3, the material plate has a wavy cross-section exhibiting spiral ripples P from any point around the center circle 10, and the spiral ripples P are inclined toward the center circle. suggested something. Note that the ripples P in the figure indicate the locus of the trough (the same applies hereinafter).

This diaphragm D was set with the convex outer surface facing the pressure receiving chamber 2 as shown by the solid line in Figure 1, and a pressure-displacement curve was obtained. It was not satisfactory (see conventional example in Fig. 4, broken line).

An object of the present invention is to reduce the above hysteresis.

[Means to solve the problem]

In order to solve the above problems, in the present invention, in the diaphragm type pressure sensor, the spiral ripple diaphragm is a disc spring whose spiral ripples are inclined outwardly in a concave shape toward a central circle, and the convex surface The disk spring is interposed between both chambers with its side facing the backup chamber, and the ram is moved to reverse the disc spring so that its convex surface faces the pressure receiving chamber.

The inclination of the spiral ripples is shown in FIG. 1
When the number is 15 or more, when press forming, with current technology,
This is because the molding pressure differs greatly between the outward facing slope and the inward facing slope, making manufacturing impossible.

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 wrinkled 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 even more effective if the beginning and end of the spiral ripple merge into the dual-use ripple.

[Effect]

In the pressure sensor configured in this way, the pressure-detected fluid is introduced into the pressure receiving chamber, the deflection of the diaphragm due to the introduced pressure is converted into movement of the ram, and the amount of movement is determined by the differential transformer. , optical sensor, laser sensor, etc.

During this action, the diaphragm is reversed and detection is made by the deflection of the reversed state, resulting in small hysteresis in boosting and lowering the pressure.

[Example I]

First, the diaphragm D will be explained.

The diaphragm D of this example is made of a stainless steel hoop 34Wφ with a thickness of 0.015mm and is pressed to have a finished outer diameter of 25.4tmφ.

Its front view and cross-sectional view are shown in FIGS. 2 and 3, and in those figures, the center circle 10 is 5aaφ, and the trough curvature of the spiral ripple P shown in FIG. 2 is r! , t1.5m, peak curvature r'
is 1.0 am, spiral ripples P are formed adjacent to each other from the Mikasa quantile of the central circle 10, the height t of the waves is 0.3 a, the height difference T between the outer periphery and the center is 1.5 ms, and the curvature R was 100 m, and the center of the curvature R was on the outside.

Two pieces of this diaphragm D were manufactured, and each was set in the aforementioned pressure sensor shown in FIG.

In the present invention, as shown by the chain line in the figure, first, the diaphragm D is interposed with the convex side facing the backup chamber 3, the adjusting screw 7 is screwed in, and the ram 5 is moved to reverse the diaphragm D. The convex surface is on the pressure receiving chamber 2 side as shown by the solid line in the figure.

On the other hand, in the conventional example, the diaphragm D was set from the beginning as shown by the solid line (in the convex side in the normal state or in the pressure receiving chamber).

In Fig. 4, which shows the pressure-displacement curves of this embodiment and the conventional example, the solid line is the embodiment, the broken line is the conventional example, ◯ indicates the pressure increase, and ⋯ indicates the pressure decrease. From this, it can be seen that the example has smaller hysteresis than the conventional example when increasing and decreasing the voltage, particularly at the start of increasing the voltage and at the end of decreasing the voltage.

Various shapes of the diaphragm D can be considered, such as those shown in FIG. In FIG. 5, concentric circular ripples P1 are formed adjacent to the center circle 10, and outer circular ripples P2 are formed concentrically with this concentric circular ripple P1 and at a predetermined interval, such that a hundred circular ripples P, , P, and the above-mentioned spiral ripple P3 is formed between them. Also in the embodiment shown in FIG. 2, an outer circular ripple P2 is formed, and the ripple P2
It is also possible to have a configuration in which the spiral ripples P are merged with the spiral ripples P.

In each example, the slope height h of the spiral ripple P, the radial length 2, and the ratio h/N were set to be 1/6 or less.

[Effects of the Invention] Since the present invention is configured as described above, the hysteresis at the time of voltage increase and decrease, especially at the start of voltage increase and at the end of voltage decrease, is reduced, and the detection accuracy of the initial state or final state is improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the pressure sensor according to the present invention, FIGS. 2 and 5 are schematic front views of each side of the diaphragm, and FIG. 3 is a sectional view of the example of FIG. Figure 4 is a pressure-displacement measurement diagram. 1... Casing, 2... Pressure receiving chamber,
3...Backup room, 4...Introduction pipe, 5...Ram,
6...Spring, 10...Central circle, P, P,...Spiral ripple, P,, P2...Circular ripple, D...・・Diafurano.

Claims (3)

[Claims] (1) The inside of the casing is divided into a pressure receiving chamber and a backup chamber by a diaphragm, an inlet pipe for the pressure-detected fluid is connected to the pressure receiving chamber, and a ram that abuts the center of the diaphragm is connected to the backup chamber, and a ram is connected to its axis. In the pressure sensor, the diaphragm is provided with a spring that biases the ram toward the diaphragm side. The ram is configured by a disc spring whose spiral ripples are inclined outward in a concave shape toward the central circle, and the disc spring is interposed in both chambers with the convex side facing the backup chamber, and the ram is moved. A pressure sensor characterized in that the disc spring is inverted so that its convex surface faces the pressure receiving chamber. (2) Claim characterized in that the ratio h/l of the inclination height h and the radial length l of the spiral ripple is 1/5 or less (
1) The pressure sensor described. (3) Concentric circular ripples are formed adjacent to the center circle of the material plate, and outer circular ripples are formed concentrically with the concentric circular ripples at a predetermined interval, and between both circular ripples, the above-mentioned spiral ripples are formed. A claim characterized in that ripples are formed (
The pressure sensor described in 1) or (2).