JPH02290522A - Pressure detector - Google Patents

Abstract

PURPOSE:To make a pressure displacement curve steep in gradient and to perform a detection in high accuracy by forming a diaphragm with a corrugated cross section showing a spiral wave ripple from the optional point of the peripheral of a base plate with circular center and making the wave ripple to incline toward the circular center. CONSTITUTION:A sensor 4 consists of a differential transformer 4a, lever 4b for moving an iron core, working ram 4c, etc. This ram 4c penetrates a member and the upper end is capable of attaching to or detaching from the diaphragm D, and the lower end is abutted to the lever 4b. The lever 4b is supported with a lever supporter 4d freely movable with swing, the under surface of which is abutted through a spring 9 to an adjuster 8 for exerted pressure penetrating the member with screwing. Then, positions of the lever 4b and the ram 4c are decided by means of adjusting a screwed-in amount of the adjuster 8, and by this adjustment, the ram 4c is pushed by the diaphragm D to move the iron core of the transformer 4a in the condition of that a deflection of the diaphragm at the time when it occurs is made to a linear state. At this time, the detected value is compensated with a consideration on an elastic force of the spring 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure detection device that uses a diaphragm to detect pressure fluctuations in a pressure-detected fluid in an analog (continuous) manner. [Prior art 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, One side 3 of pressure detection chamber 3
A sensor 4 that introduces the pressure detection fluid a into a and continuously detects the amount of deflection of the diaphragm D on the other hand.
It is common to have In this pressure detection device, in order to improve detection accuracy, it is important that the deflection characteristics of the diaphragm D be proportional to pressure changes. For this reason, conventionally,
As shown in FIG. 12, the cross-sectional shape of the diaphragm Dt has a waveform that exhibits concentric ripples P around the center circle 10 of the material plate, which improves the deflection characteristics and rise characteristics (as shown in the figure). The ripple P indicates the locus of the trough (see Figure 4; the same applies hereafter). However, this diaphragm Dt has a large rigidity because the peripheral fixed part is fixed by brazing etc.
The center 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. If the restoring force changes, the deflection/rise characteristics will change, and the detected pressure value etc. will change. Therefore, as a solution to the problem of the diaphragm D2, as disclosed in Japanese Utility Model Publication No. 40-33688, as shown in Figure 1), the ripples P are placed at two symmetrical positions around the center circle 10 of the material plate. A spiral shape is used. However, since each trough or each peak of the ripple P is at the same level, that is, it has a flat shape that is not inclined toward the center circle 10, the degree of deflection (displacement) is also small, and the displacement curve with respect to the pressing force is gentle. It becomes a slope. *Those with gradient displacement curves do not pose much of a problem in detecting fluids with rapid pressure changes, but those with gradual changes in deflection cause little change in deflection, causing problems in accuracy. In view of the above, an object of the present invention is to make the displacement curve steeper. In other words, tJRB means that it is easy to bend. (Means for Solving the Problem) In order to solve the above problem, in the present invention, in the above-mentioned conventionally known pressure detection device, the diaphragm is arranged around the center circle of the material plate at any point around the center circle. From this point of view, the waveform cross section exhibiting spiral ripples was chosen, and the spiral ripples were inclined toward the central circle.The number of ripples is preferably an odd number, and in this case, the ripples are equally distributed around the central circle. The peaks and troughs of the ripples should be continuous curved surfaces.In addition, concentric circular ripples are formed adjacent to the center circle of the material plate, and concentrically with the concentric circular ripples and at a predetermined interval. An outer circular ripple may be formed with a gap between the two circular ripples, and the spiral ripple may be formed between the two circular ripples. In this case, the beginning and end of the spiral ripple may be merged with the concentric circular ripple or the outer circular ripple. .The above-mentioned predetermined interval is determined appropriately by considering the size of the diaphragm, etc. The inclination of the above-mentioned spiral ripples, that is, the ratio of the inclination height h to the radial length l in Fig. 4 (h/l) ) should be 1/5 or less.Preferably 1/6 or less.When it is 1/5 or more, when press forming, with current technology, the molding pressure is equal to the outward slope and the inward slope. [Operation] In the diaphragm of the pressure detection device according to the present invention constructed as described above, the spiral ripples are inclined toward the central circle. As a result, the diaphragm becomes less rigid and easily deflects, resulting in a steeper pressure displacement curve. Therefore, as the pressure of the fluid to be detected increases, the diaphragm deflects smoothly, and the amount of deflection is detected analogously by a sensor. In addition, if the number of ripples is an odd number,
In Figure 1), the ripple curvatures not only between opposite sides, but also between adjacent parts (for example, parts A and C in the same figure) become closer, making the rigidity of the diaphragm more uniform. ．． If the peaks and troughs of the ripples are made into continuous curved surfaces, the bending action will be smooth. In addition, those with concentric circular ripples and outer circular ripples,
During press forming of ripples, the bulge-like distortion that occurs in the center is absorbed and dispersed by the concentric circular ripples, and the wrinkle-like distortion that occurs on the outer periphery is absorbed and dispersed by the outer circular ripples. This absorption and dispersion becomes even more effective if the beginning and end of the spiral ripples merge into both circular ripples. [Example] As shown in FIGS. 1 and 2, the casing 1 consists of three members 1a, lb, and lc, 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 puncture 2,
Due to this diaphragm D, the pressure detection chamber 3 is divided into two chambers 3a and 3.
It is divided into b. A pressure-detected fluid a is introduced into one of the detection chambers 3a from a pressure introduction port 5, and a diaphragm D is bent based on this pressure change. The entire circumference of the joint surfaces of both members 1a and 1b is sealed with a sealing member 6. Another member 1c of the casing 1 is fixed to the member 1b by a stud 7, and a sensor 4 is configured within this member 1c. The sensor 4 consists of a differential transformer 4a, a lever 4b for moving its core, an actuating ram 40, and the like. 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 has an operating pressure regulator 8 having a member 1c screwed through the lower surface thereof.
are in contact with each other via a spring S. By adjusting the screwing amount of this adjuster 8, the lever 4b and the actuating ram 4 can be adjusted.
The position of c is determined, and this adjustment allows the diaphragm D to push the actuating ram 4c and move the iron core of the differential transformer 4a when the diaphragm D is deflected, which will be described later, in a straight line state. ．． At this time, the detected value is compensated in consideration of the elastic force of the spring 9.

Next, diaphragm D will be explained. As shown in Fig. 3, this diaphragm D has spiral ripples P formed from three equally spaced points in the circumferential direction of ten central circles.
First, as shown in the same figure, spiral ripples P are formed around the center circle 10 by adjoining each other from the tertiles, and the height of the wave is t as shown in FIG. Height difference: T1 Curvature of diaphragm D: R1 Valley curvature: r and peak curvature: r' of R1 ripple P were set to predetermined values, respectively. These values are selected appropriately through experiments, etc., taking into account the location of the diaphragm D, the material, etc. If the center circle 10 is also curved as shown by the chain line in Figure 4, the border with the ripple P will be smooth. The above-mentioned diaphragm D is manufactured by press-forming and punching using a die designed based on the above-mentioned specifications (shape). Molds are basically manufactured by electrical discharge machining and are used after adjustment. To manufacture the electrode S for electrical discharge machining for manufacturing the mold, for example, the specifications of the diaphragm D are input into a milling machine capable of three-dimensional numerical control.
The end mill is used to form irregularities exhibiting ripples P shown in Fig. 5 on the surface of the electric scraping material plate. A boss 13 is attached to the electrode S obtained in this way as shown in FIG.
The electrode mounting rod 14 is erected through the electrode S, and the electrode S is mounted on an electrical discharge machine to produce a mold W.

The mold W requires a male mold and a female mold, but by forming two molds W obtained by the above electric discharge machining and performing the electric discharge machining using one of them as an electrode, the processed product and The remaining molds W provide both male and female molds. Prototypes 1 to 4 having the specifications (t, T, etc.) shown in Table 1 below were manufactured using the above manufacturing method. In addition, all stainless steel foil (hoop) is used, its thickness: 0.015fi, curvature R: 100cm, the inside of the curvature, that is, the slope is an outward convex surface, and the finished outer diameter of diaphragm D: 25.4 mm is the same in each example. In addition, the cross section of the ripple P of prototype example 1 is shown in Figure 4 (bl), and the others are as shown in the same figure (al). The number of turns of the ripple P is determined according to the width of the ripple P (valley interval d). However, it was determined that the number of times was 1 and a half times for Prototypes 1 and 2, and 2 times for 3 and 4. The manufactured diaphragm D was attached to the casing 1 as shown in Figs. 1 and 2, and Fig. 7 shows the measurement results of the pressure displacement of the diaphragm D when the pressure-detected fluid a was introduced into the detection chamber 3a. ．From this result, prototype example 1,
In case 2, the deflection is almost proportional to the pressure change, and in prototype examples 3 and 4, it is 3001mH20 or more or 5001)s
It bends almost proportionally above HzO, and it is best to operate the sensor 4 in this range. At this time, for example, if the gap between the diaphragm D and the actuating ram 4C is 0.2+uw or more in prototypes I and 2, and 0.9m or more in prototypes 3 and 4, then the diaphragm D is connected to the actuating ram 4C. There is no need to consider the elastic force of the spring 9 until the contact occurs.

As another example of the diaphragm D, as shown in FIG. 8, a concentric circular ripple P is formed adjacent to the center circle 10, and a circular ripple P8 is also formed on the outside, and both ripples Pr and Pg are formed. In between, there is a central circular ripple P. A spiral ripple P, was formed from three equal parts of the circumference of P, and the beginning and end of the ripple P merged with both ripples P1 and P:. For this diaphragm D, as in the previous example, first, the specifications of the diaphragm D are input into a milling machine capable of three-dimensional numerical control, and the end mill produces ripples P1 on the surface of the electrode material plate as shown in FIG. pg, p. The electrode S is manufactured by forming unevenness exhibiting the following. Next, this electrode S was attached to an electrical discharge machine in the same manner as described above to produce a mold W, and by press working with this mold W, the electrodes shown in FIGS. 8 and 9 were obtained. ．． During this press forming, circular ripples P1, P2 are formed on the inner and outer sides, and both ends of the spiral ripple P, merge with both ripples PI, Px. It was absorbed into the skin and no wrinkles appeared. In this example, the material is stainless steel foil with thickness: 0.015 fl, finished outer diameter: 25.4 mm, and curvature R: 10.
0 fin, its center of curvature is on the inside, and in Fig. 9, the radius d of each ripple P,, Pt, P3 (general term IP) (excluding between troughs and merging), and the trough of concentric circular ripple P1. Diameter: q, inner trough diameter q of outer ripple P, trough curvature of spiral ripple P,
Prototypes 5 and 6 were manufactured with the crest curvature r, wave height t, and height difference T as shown in Table 2 below, and when they were installed in the casing 1 shown in Figures 1 and 2, the circumferential direction Good deflection characteristics were obtained, with uniform deflection and no uneven stress.

Incidentally, the vortex ripple P, starts at an equal division of the central circular ripple P, and is completed in just over one rotation, but it is preferable to make three or more revolutions, and it is not necessary to start from only one point. It is possible to do this three times or more. In the embodiment (FIG. 3), the outer circular ripple P2 is formed, and the ripple P. It is also possible to have a configuration in which the spiral ripples P are merged with the spiral ripples P. The dimensions of each part are not limited to these, but should be selected appropriately through experiments, etc., taking into account the location of the diaphragm D, the material, etc. In addition to stainless steel foil, other known materials such as copper alloy foils such as phosphor bronze and beryllium copper, rubber, and plastics can be used as materials. Furthermore, the sensor 4 is not limited to the one in the embodiment, and may be various types such as a variable capacitance type sensor, a magnetoresistive element displacement sensor, a Hall element sensor, an overcurrent type displacement sensor, a sliding resistance type displacement sensor, a strain gauge displacement sensor, etc. Of course, well-known analog sensors can be used. [Effects of the Invention] The present invention is configured as described above, and the rigidity of the diaphragm is structurally reduced so that its pressure displacement curve becomes steep, so that the pressure of the fluid to be detected is gradually changed. It detects with high accuracy even when Additionally, there is no concentration of fatigue, buckling or cranking, and there is little change in properties such as restoring force. This effect is enhanced if the ripples are an odd number and the troughs and peaks of the ripples are curved. Furthermore, by forming circular ripples on the inner and outer sides, distortions such as wrinkles will not occur in the center and outer periphery during press molding. This effect is further enhanced by merging the spiral ripples with the inner and outer circular ripples.

[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, and FIG.
Front view of an example of the diaphragm shown in Figure 4, 18+, (b
l is the same sectional view, Figures 5 and 6 are production explanatory diagrams of the same example,
Fig. 7 is a pressure displacement measurement diagram, Fig. 8 is a front view of another example of the diaphragm, Fig. 9 is a sectional view of the same, Fig. 10 is a manufacturing explanation diagram of the same example, Fig. 1) and Fig. 12 are conventional This is an explanatory diagram of an example. D,,ox,D...diaphragm,P,P+
1Pg, Pz...Ripple, Q...Jig, R...Diaphragm curvature, r...
... Valley curvature, r' ... Peak curvature, S...
...Electrode, W...Mold, 1...
...Casing, 3, 3a, 3b...Pressure detection chamber, 4...
・Sensor 10...Central circle. Patent Applicant Tuck Electric Cable Co., Ltd. Agent Aya Kamata Figure 7 Figure 6 Figure 9 Figure 8

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 amount of deflection of the diaphragm D is introduced into the other 3b. Sensor 4 that continuously detects
In the pressure detection device, the diaphragm D has a wave-shaped cross section that exhibits spiral ripples P from any point around the center circle 10 of the material plate, and the spiral ripples P extend toward the center circle 10. A pressure detection device characterized by being inclined. (2) Incline height h and radial length l of the spiral ripple P
The pressure detection device according to claim 1, wherein the ratio h/l is 1/5 or less. (3) 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 2, an outer circular ripple P_2 is formed concentrically with the 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. Pressure detection device. (4) The pressure detection device according to claim (3), wherein the starting and ending ends of the spiral ripple P_3 are merged with the center circular ripple P_1 and the outer circular ripple P_2. (5) Claims (1) to (4) characterized in that the spiral ripples P and P_3 are an odd number of 3 or more, and each ripple starts from an equal quantile around the center circle 10 of the material. The pressure detection device according to any one of the above. (6) Claims (1) to (5) characterized in that the peaks and valleys of each of the ripples P, P_1, and P_2 are continuous curved surfaces.
) The pressure detection device according to any one of the above.