JPH03225241A - Pressure detecting device - Google Patents

Abstract

PURPOSE:To make the inclination of the pressure-displacement curve of a swirly wave patterned diaphragm steep and to make the pressure-displacement curve at the time of starting pressurization linear by forming the swirly wave pattern of the diaphragm by swirling about three or more times and making the tilt of the swirly wave pattern in a radial direction recessed on the outside. CONSTITUTION:A pressure detecting chamber 3 sectioned by the diaphragm D is formed in a casing 1. Fluid (a) whose pressure should be detected is introduced in one sectioned chamber 3a and a switch 4 which is actuated by the required quantity of deflection of the diaphragm D is provided in the other sectioned chamber 3b. Then, in the diaphragm D, the swirly wave pattern P is formed on the periphery of a central circle 10 by swirling from an optional point on the periphery. In a disk spring constituted by inclining toward the central circle 10, the wave pattern P is formed by swirling about at least three times and the tilt in the radial direction of the wave pattern P is made recessed on the outside. By applying pressing force, for example, compressed air pressure, etc., to the surface of the diaphragm D, the deflection is transmitted to all the areas through the wave pattern P. Since the entire length of the wave pattern P becomes long, rigidity is low and the degree of the deflection is high. Therefore, the inclination he pressure-displacement curve becomes steep.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pressure detection device that uses a diaphragm to detect pressure fluctuations in a pressure-detected fluid and detects the required amount of the fluid.

[Conventional technology and its problems]

This type of pressure detection device will be described with reference to FIGS. 1 and 2. A pressure detection chamber 3 partitioned by a diaphragm D is formed in a casing 1, and one side 3 of the pressure detection chamber 3 is formed in a casing 1.
Generally, the pressure detection fluid a is introduced into the diaphragm 3b, and a switch 4 which is activated by a required amount of deflection of the diaphragm D is provided at the other 3b.

In this pressure detection device, in order to improve detection accuracy, it is important that the diaphragm D has a sharp rise characteristic.

By the way, in Utility Model Application No. 1-18718 and Utility Model Application No. 1-18719, the inventors of the present invention, as shown in FIG. A pressure detector has been proposed that includes a diaphragm D with a corrugated cross section exhibiting a spiral ripple P starting from at least two quantile points. In this proposed diaphragm D, since the ripples P have a spiral shape, the surrounding rigidity is made uniform, and when the diaphragm D is bent, the stress is not biased and the diaphragm D is bent evenly in the circumferential direction. That is, the rise characteristics described above were satisfactory to some extent.

However, as shown in FIG. 6, the pressure-displacement curve (○: at pressurization, .: at depressurization, see comparative example (broken line)) lacks linearity, and is not smooth especially at the start of pressurization.

Some pressure detection devices in which this type of diaphragm D 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 overall rigidity of the diaphragm D. For this reason, first, -
It was found that the longer the total length of the spiral ripples P of the muscle, 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 diaphragm D is deflected. However, it has been found that even if the spiral ripple P is a single line, if the number of circumferences increases, the central axis will not tilt (it will tilt only to a negligible extent).

The present invention takes the above points into consideration, and aims to increase the slope of the pressure-displacement curve of the diaphragm with the spiral ripples, and to make the pressure-displacement curve at the start of pressurization linear.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, based on the above findings, in the above-mentioned pressure detection device, the number of revolutions of the spiral ripples of the diaphragm is set to three or more times, In addition, the radial slope of the spiral ripples is concave to the outside.

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 plate, 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 can also be assumed that

If the number of turns of the spiral ripple is three or more, the inclination of the central axis of the diaphragm will be eliminated when the diaphragm is corrugated, and the number of turns of the spiral ripple is preferably five or more.

[Function] In the pressure detection device configured as described above, when a pressing force, such as compressed air pressure, is applied to the surface of the diaphragm, the deflection due to the pressing force is transmitted to the entire area via spiral ripples, and the generated stress is uniformly applied. There is no deviation, and the center axis flexes evenly in the circumferential direction without tilting.

During this deflection, the total length of the spiral ripples becomes longer, so
Compared to conventional ones, the rigidity is lower, that is, the degree of deflection is greater. Therefore, the gradient of the pressure-displacement curve becomes large and becomes linear at the start of pressurization (see Examples).

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 melted distortion that occurs on the outer periphery will be absorbed and dispersed in the outer circular ripples. This absorption and dispersion, which is absorbed and dispersed in the waveform, becomes more effective if the beginning and end of the spiral ripples are merged into a perfect circular ripple.

〔Example〕

As shown in FIGS. 1 and 2, the casing 1 consists of three members 1a, 1b, and 1c, and a pressure detection chamber 3 is formed between the members 1a and 1b. A diaphragm D is interposed between both members 1a and 1b via a banking 2,
Due to this diaphragm D, the pressure detection chamber 3 is divided into two chambers 3a and 3.
It is divided into b. The pressure-detected fluid a is introduced into one of the detection chambers 3a from the pressure introduction port 5, and the diaphragm D is bent based on this pressure change. The entire circumference of the joint surfaces of both members 1d and 1b is sealed with a sealing member 6.

Another member 1c of the casing 1 is fixed to the member 1b with screws 7, and a switch 4 is configured within this member 1c. The switch 4 has a contact 4a and a lever 4b.
, actuating ram 40, etc.

The actuating ram 4c passes through the member 1b so that its upper end can move toward and away from the diaphragm D, and its lower end is in contact with the lever 4b. The lever 4b is swingably supported by a support rod 4d, and an operating pressure regulator 8 having a member 1c threaded through it is in contact with the lower surface of the lever 4b via a spring 9. By adjusting the screwing amount of this adjuster 8, the lever 4b
And the position of the actuating ram 4c is determined, and by this adjustment, at the time of the rise characteristic in the deflection of the diaphragm D, which will be described later,
Diaphragm D pushes actuating ram 4c to actuate (turn on or off) contact 4a. At this time, the detected value is compensated in consideration of the elastic force of the spring 9.

Next, the diaphragm D will be explained.

This diaphragm D is formed by forming spiral ripples P around 12 times from one point around the central circle 10, and is made of stainless steel foil with a thickness of 0.015 am;
A hoop measuring 34III1φ was pressed to have a finished outer diameter of 25.4 mmφ.

This is shown in Figures 3 and 4, in which the pitch of the spiral ripple P is d = 0.598 am, and the center circle is 1.
0 diameter S = 5.0 mm, outermost diameter of ripple P = 20.2 ms
+, curvature of valley and peak r-0,3ffll1), height of ripple P t=0.08 (Foundation), height difference T between outer periphery and center
= 1.2 mm, the curvature R of the ripple P portion = lOOmm, the center of the curvature R is set to the outside (the slope of the ripple P is concave to the outside) (the waves are omitted in Figures 3 and 4) .

On the other hand, as a comparative example, the spiral ripples P shown in FIGS. We also manufactured one in which the slope of the ripples P was outwardly convex. At this time, d,
S, r, t, T, R, etc. were all the same.

The diaphragm D of the example and comparative example manufactured in this way was set in the casing 1 as shown in Figs. It is shown in FIGS. 5 and 6. In the figure, solid lines indicate examples and chain lines (dashed lines) indicate comparative examples.

From the results shown in FIG. 5, it can be seen that the example is more
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. 6, it can be seen that the example exhibits a nearly linear pressure displacement at the start of pressurization (0 to 700 aaAg).

In the above embodiment, as shown in FIG.
A concentric circular ripple P1 is formed adjacent to the concentric circular ripple P1 around 0, and an outer circular ripple P is formed concentrically with the concentric circular ripple P1 and at a predetermined interval, and a perfect circular ripple P, , P,
A similar effect was obtained when a spiral ripple P was formed in the same circumference as in the above embodiment. In this case, the inner circular ripple P 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 ripple P2 may be formed and each spiral ripple P may be merged with the ripple P2.

Incidentally, the degree of inclination of the spiral ripples P and Pt, that is, the inclination height h and the radial length in FIG. 4! ratio (h#)
1) It is preferable to set it to 5 or less. Preferably it is 1/6 or less. 1) If it is 5 or more, the molding pressure will be significantly different between the outward slope and the inward slope during press molding, making it impossible to manufacture using the current technology.

〔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.

Further, if the spiral ripples of the diaphragm D are made into one strip, it is easier to manufacture than if a plurality of strips are formed.

[Brief explanation of drawings]

1 and 2 are a cutaway front view and a cutaway side view of an embodiment of the pressure detection device according to the present invention, FIG. 3 is a schematic front view of an example of the diaphragm of FIG. 1, and FIG. Figure 3 is a schematic sectional view, Figures 5 and 6 are pressure displacement measurement diagrams, Figure 7 is a schematic front view of the other side of diaphragm D, and Figure 8 is diaphragm D.
FIG. 9 is a schematic front view of the conventional example, and FIG. 9 is a schematic sectional view of FIG. D...Diaphragm, P, P, ,P,,P,...Ripple, R...
...Diaphragm curvature, r...Trough and peak curvature, 1...Casing, 3.3a, 3b...Pressure detection chamber, 4...
・Switch, 10...Central circle.

Claims (6)

[Claims] (1) A pressure detection chamber 3 partitioned by a diaphragm D is formed in the casing 1, and the pressure-detected fluid a is introduced into one 3a of the pressure detection chamber 3, and the required amount of the diaphragm D is introduced into the other 3b. In a pressure detection device equipped with a switch 4 that is activated by the deflection of the diaphragm D, the diaphragm D is
A corrugated cross-section exhibiting a spiral ripple P from any point around the center circle 10 of the material board, and the spiral ripple P is formed by rotating the spiral ripple P at least three times in a disc spring formed by being inclined to the center circle 10. A pressure detection device characterized in that the spiral ripples P are formed around the radial direction and have an outwardly concave inclination. (2) The pressure detection device according to claim (1), wherein the spiral ripple P is formed as a single line. (3) The pressure detection device according to claim 1, wherein the spiral ripples P are formed in a plurality of stripes, and the starting point of each spiral ripple P is equally spaced around the central circle 10. (4) Concentric circular ripples P_1 are formed adjacently around the center circle 10 of the material plate, and this concentric circular ripple P_
1, and an outer circular ripple P_2 is formed concentrically with the circular ripple P_2 at a predetermined interval, and the spiral ripple P_3 is formed between both the circular ripples P_1 and P_2. The pressure detection device according to item 1. (5) The starting and ending ends of the spiral ripples are connected to the center circular ripple P
The pressure detection device according to claim (4), characterized in that the pressure detection device merges with the outer circular ripple P_1 or the outer circular ripple P_2. (6) Incline height h and radial length l of the spiral ripple P
The pressure detection device according to any one of claims (1) to (5), characterized in that the ratio h/l is 1/5 or less.