WO2004003407A1

WO2004003407A1 - Diaphragm

Info

Publication number: WO2004003407A1
Application number: PCT/JP2003/008313
Authority: WO
Inventors: Mitsuo Taira
Original assignee: Mitsuo Taira
Priority date: 2002-06-28
Filing date: 2003-06-30
Publication date: 2004-01-08
Also published as: AU2003244016A1; JPWO2004003407A1

Abstract

A diaphragm having a gentle wave shape formed on a pressure receiving face of a partition plate of the diaphragm, where the wave shape is formed in the radial and circumferential directions of the diaphragm. Stress caused by load can be effectively relieved not only through elasticity of material, but also through deformation that is increased in proportion to pressure induced mainly by bending.

Description

Light

Diaphragm technical field.

The present invention is a matter of course in the fields of pressure sensor elements, diaphragm pumps, switches, regulators, pressure transmitters, diaphragms, etc., and can respond to new fields used at high temperature and high pressure. Along with securing a large amount of radial deformation while having a restoring force, the stress caused by the load made of elastic materials such as rubber, resin, metal, etc. that can achieve a long service life is only due to the elasticity of the material The present invention relates to a diaphragm having a wavy shape that deforms in proportion to a pressure mainly composed of bending without being able to effectively reduce stress caused by a load. Background art

Initially, the diaphragm used a plate-shaped diaphragm, and the diaphragm was bent by utilizing the elastic deformation of the diaphragm due to the difference in pressure acting on both sides of the diaphragm by sealing the periphery of the diaphragm. Met.

In other words, the peripherally constrained diaphragm is such that the pressure receiving surface bends due to the pressure difference acting on both surfaces, and the deflection is used to detect the pressure, and to control the pressure and operate the pressure-related equipment. Often used.

In other words, this diaphragm is used to apply a proportional relationship between differential pressure and displacement, for example, to measure pressure or to control the opening of a valve. In order to secure a large amount of this radial deformation, the thickness of the diaphragm itself must be reduced or its diameter must be increased so that a predetermined elastic deformation can be expected. However, reducing the wall thickness in this way can reduce the pressure resistance performance. Invite. In addition, if the diameter is increased, the size of the device itself is increased. However, increasing the withstand pressure of the diaphragm inevitably results in high rigidity and sacrificing displacement, while increasing the displacement requires lowering the rigidity. It is difficult to reduce rigidity from the viewpoint of rigidity, and high rigidity must be achieved despite low rigidity. Was preventing the realization of Noh.

As described above, there is a limit in responding only to the raw deformability of the diaphragm “I”, and a proposal has been made to improve the amount of deflection by concentrically applying a corrugated waveform to the cross section of the diaphragm. (Japanese Patent Application Laid-Open No. 54-160949, Japanese Patent Application Laid-Open No. 59-20967, Japanese Patent Application Laid-Open No. 2-51664, Japanese Patent Application Laid-Open No. 91-28659) '-All of the above proposals were based on earlier technologies such as “waveforms with uniform amplitude” and “die with equal waveform peaks and equal peak heights. It is trapped in a concentric wave that does not effectively relieve any stress associated with the load.

The present inventor investigated where (where) the above-mentioned conventional technical common sense that “the amplitude of the waveform is uniform” originated.

The elucidation of the truth has been sought from papers and publications listed in the following chronological order.

1) M.D. Hersey in NACA Rept. 165, 1923 as a reference for diaphragms used in measuring instruments.

2) The theory of such membrane deflection was discussed by K. Stange.

"Ingr.—Arch., Vol.2, R47, 1931J

3) `` THEORY OF PLATES AND SHELLSj 1959

4) Theory of Plates and Seals <Lower> 1st edition published on July 27, 1973 5) "Finite Element Method for Nonlinear Continuum 2" January 20, 1980 First edition issued

6) `` Modern Material Mechanics '' 1 Aug. 20, 2016 First Edition 1st Edition

In the above, the technology introduction with "Waveform amplitude is uniform"

“THEORY OF PLATES AND SHELLS”, p. 404 and “plate and shell theory”, p. 380, a cross-sectional waveform diagram is presented as Figure 202 (Figure 12 of the present application). The text quoted in the article 2 states, "As often required in various measuring instruments, to obtain a deflection proportional to pressure, a corrugated membrane ³ as shown in Fig. 202 (Fig. 1) As a wavy result, the deformation mainly consists of bending, where the deformation increases in proportion to the pressure ⁴ If the waveform follows the sine law, the wave along the diameter If the number of is large enough (11> 5), then using the notation in Figure 186, it is written as "■ · ·."

—On the other hand, in “Modern Material Mechanics”, P 2 0 3, 10.4 “Axisymmetric Bending of a Disk”, “Therefore, τ χ ^ = τ ζ θ = 0 and 1 0.1 According to the assumption (iii) in the section, there are three forces acting on the small element abcd in the disk, including σ _z = 0, and σ _,, σ θ, and _rz . It is written in. In addition, it is shown in FIG. 11 of the present application.

Σ r is the normal stress acting in the radial direction

σ θ is the normal stress acting in the circumferential direction

τ _rz is the shear stress along the thickness direction

Hereafter, these are referred to as radial stress, circumferential stress, and plate thickness stress. In addition, in P.135 of “Finite element method of nonlinear continuum 2”, the disk is displaced by the load, which is called “Deformed shape of finite element model of disk for various pressure values”. A diagram modeling the process shows that as the displacement increases with increasing load, the radius increases, the circumference increases, and the plate thickness decreases. Both books clearly show the changes in the radial direction, circumferential direction, and thickness direction as described above. >'' Does not seem to be consistent o

Therefore, the present inventors have studied “waveform”.

1) “Theory of Plates and Shells Below” in Fig. 12 The waveform shown as a cross-sectional view of a concentric waveform diaphragm introduced as Fig. 202 in P380. ·

2) Waveform seen as Y-Y 'side view in Fig.13.

3) Waveforms shown as A-A 'cross section in Fig. 13.

It should be noted that FIG. 13 described above shows the angular corrugated plate 1.

2 is a waveform represented by the side surface of the corrugated plate, and 3 is a waveform represented by a cross section when the plate 1 is cut in the AA ′ direction. These 2 and 3 have similar waveforms, but have a high degree of freedom in expansion and contraction in the Y-Y 'direction, but also expand and contract in the A-A' direction, which is formed in a relationship that does not move in the X-X 'direction. Cannot be expected.

Although these three types of waveforms are not the same size, they are the same in that they exhibit waveforms, but are described in "Theory of Plates and Seals <below>". As a result of the waveform, the deformation mainly consists of bending, where the deformation increases in proportion to the pressure. If we accept this claim as it is, all three waveforms will perform the same function. However, the waveforms that can be seen as side views and the waveforms that appear as cross-sections have different meanings and functions, so the waveforms shown in the three types of cross-sections and side views are the same, so the same expression is used. We cannot accept the argument that they have the same function. In other words, considering the state of the part behind the waveform and on the opposite side of the waveform and invisible, 1) “Theory of plate and shell below” in Fig. 12 The background of the waveform introduced as Fig. 202 in P380 is based on the description of Diabram theory. If the number of waves is large enough (n> 5), it is natural that it is not mistaken to associate a diaphragm with a concentric waveform. .

2) The waveform seen as Y-Y, side view in Fig. 13 is a side view. Behind this waveform, the direction perpendicular to the side view, that is, no matter where the background is cut (side view) (Positions parallel to the figure) Represent waveforms of the same dimensions. This is a rectangular corrugated plate, whose shape is "The deformation mainly consists of bending as a result of the waveform," so it is possible to expand and contract in the Y_Y 'direction, but this is only This is a two-dimensional deformation, which is completely different from the three-dimensional deformation described later.

3) The A-A 'cross-sectional waveform in Fig. 13 is a waveform that appears as a cross-sectional view. In the background of this waveform, the corrugated sheet is hidden at a certain angle in the A-A' cross-section. I have. In this case, no matter how much the cross section shows a waveform, it cannot be expected to expand or contract in the A–A direction.

Although not the same, the cross-sectional waveform in Fig. 12 can also expand and contract in the left-right direction of the cross-section in Fig. 12 because a plurality of arc waves in the background exert resistance. I don't.

In addition, there is a spiral diaphragm that assumes that it is possible to cope with both radial stress and circumferential stress by applying waves in the combined direction of the radial direction and the circumferential direction. It cannot exert any function against two stresses in the radial and circumferential directions, such as “brace” used as a reinforcing material for “columns” and “beams”.

The above three types of cross-sectional views or side views show the waveforms and their backgrounds.However, even though the waveforms are the same, their backgrounds are different. As mentioned above, no one thinks that these three types can exert the same expression and the same function even if they are considered common sense.

Furthermore, in the quoted text, "In that case, using the notation shown in Fig. 186, there is" ......, but in Fig. 186, there is a section in Chapter 11, Bending of Anisotropic Plate, It discusses a board, the same square corrugated board as in Figure 13. The waveform seen as a side view of this square plate is the same as that in Fig. 12.… The method of capturing only the identity of the waveform and pressing the theory of the square plate onto the disk is a bit too violent. And nobody understands it as proper reasoning.

Here, while assuming a concentric waveform, the fact that the cross-section shows a waveform, the unawareness of the fatal error of applying the waveform theory of a square plate with different circumstances was clarified.

Based on the above-mentioned knowledge, the present invention effectively relieves the stress caused by the load, which simultaneously reduces the radial stress, the circumferential stress, and the thickness stress as shown in Fig. 11 The purpose is to provide a diaphragm that can be used. Disclosure of the invention

The basic concept of the present invention for achieving the above object will be described with reference to FIGS.

FIG. 1a shows the “normal stress σ rj acting in the radial direction” introduced in FIG. 11 described above. As shown in FIG. 2a, a concentric circular stress is used as a means of relaxing the stress in the radial direction. Figure lb shows the “normal stress σ θ acting in the circumferential direction”. As a means of relaxing the stress in the circumferential direction, as shown in FIG. The mitigation measures for these two directions are equivalent to the corrugated square plate of Fig. 13 in which X--X 'is rounded in the circumferential direction on the plane and Y--Y' is rounded in the circumferential direction on the plane. However, Fig. 1c is a mixed stress diagram in the radial and circumferential directions, and the means for stress relaxation corresponding to the stress in Fig. 1c is as shown in Fig. 2c. However, a three-dimensional waveform is formed for the first time by combining a concentric waveform and a waveform having an outward spread on the circumference. With the generation of the load, three-dimensional deformation is possible at each part of the three-dimensional waveform urged on the diaphragm pressure receiving surface. .

If the shape does not cause stress concentration, a large displacement can be realized by minimizing the applied stress against the "shear stress τ r _Z along the thickness direction" introduced in Fig. 11. And high withstand pressure.

That is, the stress relaxation in the plate thickness direction is secondaryly achieved by normal functioning of the stress relaxation ability in the radial direction and the circumferential direction, and the stress relaxation is completed here.

Without being confused by the size of the expression, the basic stress that occurs equally in all elastic materials is grasped from the viewpoint of material mechanics, and we are trying to clarify the proposition that the original diaphragm should be… It does not specify

As described above, all three stresses in the radial, circumferential, and thickness directions can be handled.

That is, in the present invention of claim 1, a three-dimensional waveform is formed on the pressure receiving surface by applying a gentle waveform surface in the radial direction and the circumferential direction of the diaphragm pressure receiving surface.

The present invention according to claim 2 provides a diaphragm having a single annular groove, by dividing and providing different concave shapes and applying a gentle wavy surface in the circumferential direction, so that the entire annular groove has a three-dimensional waveform. did. '

The present invention according to claim 3 provides a diaphragm in which concentric waveforms are formed, in which a concentric corrugated peak and a bottom are divided and a deformed peak and a bottom are divided and provided. Three-dimensional waveforms on the pressure-receiving surface by applying a gentle wavy surface in the circumferential direction over the entire area of the wavy shape in the radial direction by arranging the bottom part equally and occlusally.

According to the fourth aspect of the present invention, the uneven protrusions having a stress relaxation function are gradually increased in diameter toward the fixed end of the outer periphery of the diaphragm, are uniformly arranged, and have a three-dimensional waveform on the receiving surface.

According to the fifth aspect of the present invention, the diameter of the convex protrusion having the stress relaxing function is gradually increased toward the fixed end of the outer periphery of the diaphragm, the convex and convex are arranged uniformly, and a three-dimensional waveform is formed on the pressure receiving surface.

The present invention according to claim 6 is characterized in that, in a portion composed of uneven protrusions having a stress relaxation function and surrounded by a locus in which the unevenness and the convexity change near the diaphragm reference plane, a curved pleat is formed on a base circumference thereof. Then, the pressure receiving surface was made into a three-dimensional waveform.

Thus, in the present invention, a gentle waveform in the radial direction and a gentle waveform in the circumferential direction corresponding to all the stresses in the stress field generated by the load in the diaphragm pressure receiving surface. Each part of the three-dimensional waveform that appears at the time has its own independence and uniqueness, but also functions as a harmonious aggregate as a whole, enabling three-dimensional deformation at each part of the pressure receiving surface, Demonstrates high pressure resistance. BRIEF DESCRIPTION OF THE FIGURES

1a to 1c are explanatory diagrams of the direction of the stress acting on the diaphragm pressure receiving surface.

2a to 2c are explanatory diagrams showing the basic principle of the present invention described in claim 1 in which the stress relaxation means shown in FIGS. 1a to 1c is applied.

3A and 3B are plan views of the diaphragm according to the present invention described in Claim 2. FIG. 3A is a cross-sectional composite view taken along line A—A and line B_B in FIG.

4a and 4b are overhead views showing the diaphragm of the present invention corresponding to FIGS. 3a and 3b.

FIG. 5 ab is a plan view of the diaphragm of the present invention described in claim 3. FIG. 5 a is a cross-sectional view taken along line AA, line BB, and line C-C in the figure.

FIG. 6 ab is a perspective view of the diaphragm of the present invention corresponding to FIGS. 5 a and 5 b.

FIG. 7 is a plan view of the diaphragm of the present invention described in claim 4 _c . FIG. 8 is a plan view of the diaphragm of the present invention described in claim 5 FIG. 9 is a plan view of the diaphragm of claim 6 _c Figure 1 0 is a plan view of Daiaburamu of the invention described is a different embodiment illustrating the FIG. 7, 8.

Figure 11 is an explanatory diagram of the section "Modern Material Mechanics" P203, 10.4 "Axisymmetric bending of a disk".

FIG. 12 is a drawing of FIG. 202 of P380, “Theory of Plate and Shell”.

Figure 1 3 is a side waveform with angular corrugated plate, _c Figure 1 4 a to c is an explanatory view of the sectional waveforms, dimensions view of a sample for 'comparison test between the present invention benefits a conventional means, a Shows a plate-like diaphragm, b shows a conventional concentric waveform diaphragm, and c shows a diaphragm to which the present invention is applied.

FIG. 15 is a graph showing the relationship between the sample pressure and the radius shown in FIGS. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings.

FIG. 2c shows the invention as set forth in claim 1. ' By combining the radial waveform 4 and the circumferential waveform 4 of the diaphragm pressure receiving surface 5, a three-dimensional waveform 4 ′ is performed.

Each part of the three-dimensional waveform 4 ', which has a stress relaxation function, responds to all stresses generated by the load, and has its own independence and uniqueness, and harmonizes as a whole.

In other words, by effectively relaxing the vertical stress σ r acting in the radial direction due to the load, the vertical stress σ θ acting in the circumferential direction, and the shear stress τ _rz along the thickness direction, large displacement and high withstand It not only exerts pressure but also increases reliability and safety by increasing accuracy and durability.

3 and 4 show the invention as set forth in claim 2.

This is used for diaphragms, pressure response, etc. A diaphragm with one annular groove 9 between the vibrating part 7, the center plate fixing part 7 and the outer peripheral fixing part 8, with different concave shapes 10 divided and provided in a smooth manner in the circumferential direction. By applying a corrugated surface, the entire annular groove composed of different concave shapes 9, 10 was made into a three-dimensional waveform.

5 and 6 show the invention as set forth in claim 3.

In the diaphragm with the concentric waveform 11 formed in the c-c cross section, the irregularly shaped peaks 1 2 ′ and the bottom 13 ′ are equally bitingly arranged at the peaks 12 and the bottom 13 of the concentric waveform. Thus, a three-dimensional waveform was formed on the pressure receiving surface by applying a smooth waveform surface in the circumferential direction over the entire area of the waveform in the radial direction.

FIG. 7 shows the invention as set forth in claim '4.

The solid line pattern in the drawing is a changing locus of the concave protrusion a and the convex protrusion b near the diaphragm reference plane, and c indicates a portion surrounded by the locus. The concave projections a and the convex projections b having the stress relaxation function were gradually enlarged toward the outer peripheral fixed end of the diaphragm, and the concave a and the convex b were uniformly arranged and shaped, and the pressure receiving surface was formed into a three-dimensional waveform. FIG. 8 illustrates the invention as set forth in claim 5.

The solid line pattern in the figure is a locus where the convex protrusions b and b change near the diaphragm reference plane, and c indicates a portion surrounded by the locus. The convex protrusions b and b having the stress relaxation function were gradually enlarged toward the outer peripheral fixed end of the partition plate, and the convex protrusions b and b were uniformly arranged and shaped, and the pressure receiving surface was formed into a three-dimensional waveform.

FIG. 9 illustrates the invention as set forth in claim 6.

A curved fold is formed on the base circumference of the part c, which is surrounded by the locus where the concave protrusions a and the convex protrusions b and the convex protrusions b and b change in the vicinity of the diaphragm reference plane in FIGS. 7 and 8. In this way, the stress relaxation ability was improved.

7 and 8, the solid line pattern consists of curves passing through the center, while FIG. 10 shows an example in which the pattern consists of curves that do not pass through the center. The central unshaped part 14 in the center moves up and down, albeit with some deformation at the center, so even if it is fully attached to the center, it will be judged by the relationship between investment and effect Whichever choice is made, it has no effect on the overall picture.

Also, in the change region of the concave a and the convex b or the convex b, it is formed with an appropriate R, and the waveform arranged on the diaphragm pressure receiving surface has no stress concentration due to the waveform urging. Obviously, a smooth three-dimensional waveform is required.

Although the present embodiment has been described in detail, the present invention is not limited to this specific embodiment, and various changes can be made without departing from the spirit of the present invention. It is not something that should be taken into account.

A comparison test between the prior art and the present invention was performed as follows.

FIGS. 14a to 14c are dimensional diagrams of a flat plate as a basic shape, a conventional concentric wave, and a three-dimensional waveform of the present invention. Same at 6 mm.

The material used was an inappropriate PC / ABS resin. This material is not a diaphragm resin. Because, in this case, by applying a three-dimensional wave shape to the diaphragm pressure receiving surface, it is possible to perform shape deformation and three-dimensional deformation. The idea is to create Note that there must be no stress concentration due to the shape on the three-dimensional shape surface urged against the pressure receiving surface.

In this sense, the use of a resin that is strong and has no soft core but has fluidity and a core (somewhat hard) contains a PC to find the initial target shape defects. The point that it is unsuitable for diaphragms has no meaning in this case because it means that it is possible.

FIG. 15 shows the pressure-deflection relationship of these samples _a , b, and c.

The results clearly show that a is proportional to the pressure due to relying solely on elasticity but has a limit on deflection, and b is a failure to cope with stress due to failure to cope with the stress and that the deflection flattens out. Was.

In contrast, for c, it was confirmed that the deflection continued to increase while maintaining the proportional relationship.

In addition, the results described above are explained in detail.

Since the flat diaphragm has not been modified in any way on the pressure-receiving surface, the pressure-receiving surface is subjected to a tensile force in the radial direction and the circumferential direction together with the load, and the plate thickness decreases with the displacement. Naturally, both the displacement and the pressure resistance are the lowest among these three types of diaphragms.

The concentric corrugated diaphragm has a wave pattern in the radial direction, but no work in the circumferential direction. On the pressure-receiving surface, it tends to bend in the radial direction as a wavy deformation with the load, but the radius A pulling force acts on the entire circumference passing through the throat point, which hinders displacement. So there is a pressure resistance, but the displacement is much less than you might imagine.

The diaphragm of the present invention includes a content which can easily understand the vertical stress (ar) acting in the radial direction, the vertical stress (σ 0) acting in the circumferential direction, and the shear stress (te) in the thickness direction. .

a) As a countermeasure for the normal stress acting in the radial direction (Fig.

The concentric corrugations in Fig. 2-a are used as radial stress relaxation means.

b) As a countermeasure against the vertical stress acting in the circumferential direction (Fig. 11-b),

Circumferentially corrugated means shown in Fig. 2-b will be used as circumferential stress relaxation means.

c) Among the three stresses on the pressure receiving surface, the two stresses σ _Γ and σ θ (Fig.

Figure 2-c, which is a combination of Fig. 2-a concentrically corrugated and Fig. 2-b corrugated on the circumference, is used as a means for mitigating two stresses. Let's consider the process by which such a modified diaphragm behaves with the load.

a) At the same time as the load is applied, the radial and circumferential relaxation capacity is exerted, and the deformation is mainly caused by bending, Therefore, the deformation increases in proportion to the pressure. "

The biggest difference between what is meant in the quoted text and what is meant by the invention is

In contrast to the quote that only proposes the mitigation ability in the radial direction, the invention has the mitigation ability in both the radial and circumferential directions. This difference is the B-graph represented by the concentric waveform diaphragm, which has no mitigation ability in the circumferential direction. Since only one side has the mitigation ability, the load starts to be applied, and at the same time, the other side that does not have the mitigation ability displaces.The brake is applied to the deformation, and this brake increases with the load, and both have the mitigation ability In the present invention, as shown in the graph, the pressure and the displacement are displaced in a correct proportional relationship.

b) Even if it has the relaxation ability in both the radial direction and the circumferential direction, it does not mean that the ability is completely equal, but when the load increases and the displacement progresses, one of the The mitigation ability is used up. In this state, the processing form shifts to a tensile deformation rather than a wavy deformation, the brakes become stronger, and the graph no longer shows a proportional relationship.

c) The brakes work strongly with the displacement, but as long as there is no stress concentration due to the shape of the device, they will withstand the pressure but eventually break down.

d) What is important here is that the "deformation mainly consists of bending as a result of the wavy shape". This is the part where the ability to relieve stress in the radial and circumferential directions is appropriate. The deformation in the pressure receiving surface is made possible by the wavy deformation in the radial and circumferential directions, and the damage in the thickness direction can be minimized. Making the displacement possible with three-dimensional deformation suppresses the reduction in the thickness of the sheet, and as a result enables high displacement and high withstand voltage. Industrial potential for lj

As described above, the diaphragm according to the present invention can effectively alleviate the stress caused by the load, not only by the properties of the material, but by the deformation that increases in proportion to the pressure mainly caused by bending. So, to secure the radius allowance Needless to say, the fields of pressure sensor elements, diaphragm pumps, switches, regulators, pressure transmitters, diaphragms, etc., with waveforms in the radial and circumferential directions of the pressure surface.

The diaphragm according to the present invention is made of a flexible material such as rubber, resin, and metal, and realizes large displacement and high withstand pressure regardless of the material, thereby realizing high accuracy and long life. By aiming for a high-temperature, high-pressure, corrosion-resistant time limit that has not yet been reached, we hope that technology will be involved in the emergence of unexplored industrial equipment.

Claims

Scope of request A diaphragm that can form a three-dimensional waveform on the pressure receiving surface by applying a gentle corrugated surface in the radial direction and the circumferential direction of the pressure receiving surface of the partition plate, and effectively reduce the stress caused by the load .

-The diaphragm having one annular groove, wherein different concave shapes are separately provided and a gentle wavy surface is provided in a circumferential direction so that the entire annular groove has a three-dimensional waveform. Diaphragm that can effectively relieve the stress associated with the load of the vehicle.

In a concentrically corrugated diaphragm, the concentric corrugated peaks and bottoms are divided into irregularly shaped peaks and bottoms, and the irregularly shaped peaks and bottoms are equally divided and the radius is increased. A diaphragm capable of effectively relieving the stress caused by the load according to claim 1 by forming a three-dimensional waveform on the pressure receiving surface by applying a gentle waveform surface in the circumferential direction over the entire area of the waveform in the direction. .

The claim 1 wherein the 1H-shaped protrusions and the convex protrusions having a stress relaxation function are gradually enlarged toward the outer peripheral fixed end of the partition plate, and are arranged so as to be evenly uneven, so that the pressure receiving surface has a three-dimensional waveform. A diaphragm that can effectively relieve the stress associated with the load on the vehicle.

5. The convex protrusions having a stress relaxation function and the convex protrusions are gradually enlarged toward the outer peripheral fixed end of the partition plate, and are uniformly arranged and formed to have a three-dimensional waveform on the pressure receiving surface. A diaphragm capable of effectively relieving the stress associated with the load described in paragraph 1.

6. Curved folds are formed on the base circumference of the part surrounded by the locus where the concave projection and the vertical projection having the stress relaxation function and the convex projection and the convex projection change near the reference plane of the diaphragm. According to the load described in claims 1, 4 and 5, Diaphragm that can effectively reduce stress