Metal diaphragm and manufacturing method of the same

Abstract

To provide a metal diaphragm and a manufacturing method of the same.SOLUTION: A metal diaphragm that is made of a punched material of a rolled metal sheet made of metal having rolling anisotropy, and has a partial spherical shell shape, has an identification part in at least one direction of a first direction as a 45° ±6° direction around the partial spherical shell shape from a rolling direction of the rolled metal sheet, a second direction as a 135° ±6° direction around the partial spherical shell shape, a third direction as a -45° ±6° direction around the partial spherical shell shape, and a fourth direction as a -135° ±6° direction around the partial spherical shell shape.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a metal diaphragm and a method for manufacturing the same.

Background Art

[0002] Since diaphragms used in clean valves generally require high elasticity, metal plates with a high degree of cold rolling are used. Since this metal plate has rolling anisotropy, even if the material is pressed and drawn into a concave spherical shape, the desired partial spherical shell shape cannot be obtained. In order to obtain a partial spherical shell shape, it is necessary to perform drawing forming with a die shape that takes into account rolling anisotropy, and at that time, it is necessary to identify the rolling direction of the metal plate. As a method for identifying the rolling direction, for example, it is conceivable to provide an identification mark such as printing, etching, or notching on the metal plate.

[0003] In the following Patent Document 1, a technique for forming a notch along the rolling direction on a metal plate is disclosed. In the following Patent Document 2, a technique for forming an orientation flat along the rolling direction on a metal plate is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the drawing forming of a metal plate having high elasticity, sufficient processing accuracy is required, and in particular, it is necessary to minimize the deviation of the drawing forming position with respect to the direction of the rolling direction of the metal plate. However, since the rolling direction and the direction perpendicular thereto are positions that are easily affected by the drawing process, it is not always easy to identify the exact orientation. Furthermore, when notches or orientation flats are formed in the rolling direction or perpendicular thereto, there is a problem that, in the case of a metal plate material having high elasticity and rolling anisotropy, distortion is likely to occur in the partial spherical shell shape after forming.

[0006] In view of the above-mentioned problems, an object of the present invention is to provide a metal diaphragm and a method for manufacturing the diaphragm that enable highly accurate drawing. [Means for solving the problem]

[0007] (1) A metal diaphragm according to the present invention is a diaphragm made of a stamped material of a rolled metal plate having rolling anisotropy and having a partial spherical shell shape, characterized in that it has an identification portion in at least one of the following directions: a first direction that is a 45°±6° direction around the circumference of the partial spherical shell shape from the rolling direction of the rolled metal plate; a second direction that is a 135°±6° direction around the circumference of the partial spherical shell shape; a third direction that is a -45°±6° direction around the circumference of the partial spherical shell shape; and a fourth direction that is a -135°±6° direction around the circumference of the partial spherical shell shape.

[0008] In a metal diaphragm made from a punched material of a rolled metal plate having rolling anisotropy, by providing an identification part in any of the first to fourth directions, when the punched material is bent along the rolling direction and then drawn to obtain a partial spherical shell shape, the bending direction can be accurately determined before the drawing process can be performed. By correctly selecting the bending direction before drawing, a metal diaphragm having the desired partial spherical shell shape can be obtained. In contrast, determining the direction when bending a punched material without an identification part is not easy, and if the direction during bending is incorrect, it is not possible to obtain a metal diaphragm having the desired partial spherical shell shape. Also, by providing an identification portion in the rolling direction or the direction perpendicular to the rolling direction, it is possible to grasp the directionality in the case of bending. However, if an identification portion such as a notch or an orientation flat is provided in the rolling direction or the direction perpendicular to the rolling direction, stress is applied to the punched material during the drawing process, causing distortion in a partial spherical shell shape starting from the identification portion such as the notch or the orientation flat. The distortion generated in the partial spherical shell shape becomes an undesirable defect for the diaphragm which is a precision part. Therefore, by providing the identification portion in any of the aforementioned first to fourth directions, it contributes to the formation of a partial spherical shell shape without distortion.

[0009] (2) In the metal diaphragm according to one embodiment of the present invention, it is preferable that the first direction is a direction of 45° ± 3° around the plane view, the second direction is a direction of 135° ± 3° around the plane view, the third direction is a direction of -45° ± 3° around the plane view, and the fourth direction is a direction of -135° ± 3° around the plane view.

[0010] Preferably, the first direction is a direction of 45° ± 3°, the second direction is a direction of 135° ± 3°, the third direction is a direction of -45° ± 3°, and the fourth direction is a direction of -135° ± 3°. By selecting these directions, it is possible to obtain a metal diaphragm having a partial spherical shell shape with less distortion.

[0011] (3) In the metal diaphragm according to one embodiment of the present invention, it is preferable to have an identification portion in the first direction and the second direction, or to have an identification portion in the third direction and the fourth direction.

[0012] If the punched material has an identification portion in the first direction and the second direction, or in the third direction and the fourth direction, the bending direction when bending the punched material can be surely and easily set. For this reason, it is possible to surely and easily obtain a diaphragm having a partial spherical shell shape without distortion.

[0013] (4) In the metal diaphragm according to one embodiment of the present invention, it is preferable that the identification portion is a notch or an orientation flat.

[0014] When the identification portion is a notch or an orientation flat, if these identification portions are formed in the rolling direction or the direction perpendicular to the rolling direction, when forming a partial spherical shell shape by drawing, the distortion becomes large. However, if a notch or an orientation flat is formed in any of the aforementioned first to fourth directions, a partial spherical shell shape with less distortion can be obtained by drawing.

[0015] (5) In the metal diaphragm according to one embodiment of the present invention, it is preferable that the rolled metal sheet is made of any one of a Co-Ni based alloy, stainless steel, a Ni-Mo-Cr based alloy, a Ni-Cr based alloy, and a Ni based alloy.

[0016] Co-Ni based alloys, stainless steels, Ni-Mo-Cr based alloys, Ni-Cr based alloys, and Ni based alloys are all metals having high elasticity and rolling anisotropy. If the metal diaphragm is made of these metals, a diaphragm rich in elasticity and excellent in responsiveness can be provided. In addition, since these metals are also excellent in corrosion resistance, a diaphragm excellent in corrosion resistance can be provided.

[0017] (6) The manufacturing method of a metal diaphragm according to one embodiment of the present invention punches a rolled metal sheet having rolling anisotropy to form a punched material, and performs primary processing of symmetrically bending the punched material with a straight line parallel to the rolling direction as the center line. When performing secondary processing to form a diaphragm having a partial spherical shell shape by drawing, among a first direction that is 45° ± 6° in the circumferential direction of the partial spherical shell shape, a second direction that is 135° ± 6° in the circumferential direction of the partial spherical shell shape, a third direction that is -45° ± 6° in the circumferential direction of the partial spherical shell shape, and a fourth direction that is -135° ± 6° in the circumferential direction of the partial spherical shell shape, after punching the rolled metal sheet to form the punched material so as to have an identification portion in at least one of the directions, with a straight line parallel to the rolling direction recognized with the identification portion as a mark as the bending center line, the primary processing is performed on the punched material.

[0018] In the manufacturing method of a metal diaphragm made of a punched material of a rolled metal sheet having rolling anisotropy, when an identification portion is provided in any of the first to fourth directions and the punched material is bent along the rolling direction and then a partial spherical shell shape is obtained by drawing forming, bending can be performed after reliably grasping the bending direction, and then drawing forming can be performed. By performing drawing after correctly selecting the bending direction, a metal diaphragm having the target partial spherical shell shape can be obtained. On the other hand, it is not easy to determine the direction when bending the punched material without an identification portion. If the direction during bending is different, a metal diaphragm having the partial spherical shell shape of the target shape cannot be obtained.

[0019] Also, by providing the identification portion in the rolling direction or the direction perpendicular to the rolling direction, it is possible to grasp the directivity when bending. However, if an identification portion such as a notch or an orientation flat is provided in the rolling direction or in the direction perpendicular to the rolling direction, during the drawing process, stress is applied to the punched material being processed starting from the identification portion such as the notch or the orientation flat, causing distortion in the partial spherical shell shape. The distortion generated in the partial spherical shell shape becomes an undesirable defect for the diaphragm which is a precision component. Therefore, by providing the identification portion in any one of the aforementioned first to fourth directions, a diaphragm having a partial spherical shell shape without distortion can be formed.

[0020] (7) In the method for manufacturing a metal diaphragm according to one embodiment of the present invention, it is preferable that the first direction is a direction of 45° ± 3° around the plane view, the second direction is a direction of 135° ± 3° around the plane view, the third direction is a direction of -45° ± 3° around the plane view, and the fourth direction is a direction of -135° ± 3° around the plane view. (8) In the method for manufacturing a metal diaphragm according to one embodiment of the present invention, it is preferable to form the identification portion in the first direction and the second direction, or to form the identification portion in the third direction and the fourth direction. (9) In the method for manufacturing a metal diaphragm according to one embodiment of the present invention, it is preferable to form a notch or an orientation flat as the identification portion. (10) The method for manufacturing a metal diaphragm according to one embodiment of the present invention is characterized in that any one of a Co-Ni based alloy, stainless steel, Ni-Mo-Cr based alloy, Ni-Cr based alloy, and Ni based alloy is used as the metal material constituting the rolled metal sheet.

Advantages of the Invention

[0021] The metal diaphragm according to the present invention has a configuration in which a discrimination portion is provided in at least one of the first to fourth directions in a punched material of a rolled metal sheet having rolling anisotropy. Thereby, when obtaining a partial spherical shell shape by drawing forming after bending the punched material of the rolled metal sheet along the rolling direction, it is possible to perform the drawing forming after bending in the correct direction. By being able to perform the drawing forming without being affected by the discrimination portion provided in any of the first to fourth directions after performing the bending in the correct direction, a metal diaphragm having a partial spherical shell shape with less distortion can be obtained.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0023] Hereinafter, embodiments of the diaphragm according to the present invention will be described with reference to the drawings. In the following embodiments, as an example of the diaphragm, a dome-shaped diaphragm having a partial spherical shell shape will be described. In the drawings used in the following description, the scale of each member is appropriately changed and shown in order to make each member recognizable in size.

[0024] "First Embodiment" FIG. 1 shows a strip-shaped rolled metal plate 1, which is made of, for example, any one of Co-Ni-based alloys, stainless steels, Ni-Mo-Cr-based alloys, Ni-Cr-based alloys, and Ni-based alloys. The stainless steel may be any of austenitic stainless steel, austenitic-ferritic duplex stainless steel, ferritic stainless steel, martensitic stainless steel, etc. These metal materials have high elasticity and excellent corrosion resistance, and are suitable metal materials for constituting the diaphragm.

[0025] The rolled metal plate 1 is made of any of the above-mentioned metal materials, but the rolled metal plate 1 is processed into a strip shape by rolling, and the rolling direction LD is a direction parallel to the length direction of the rolled metal plate 1. Incidentally, the rolled metal sheet 1 has a thickness of about 0.03 mm to 0.5 mm as an example. Also, since the rolled metal sheet 1 is manufactured by rolling the aforementioned metal material, the crystal grains constituting the metal structure of the rolled metal sheet 1 are stretched in the rolling direction. For this reason, when comparing the strength in the rolling direction and the strength in the direction perpendicular to the rolling direction (width direction: TD) of the rolled metal sheet 1, the strength in the direction perpendicular to the rolling direction is higher. In other words, the strength when bending with a straight line perpendicular to the width direction as the bending line with both ends in the front and rear of the rolling direction of the rolled metal sheet 1 as the ends is higher than the strength when symmetrically bending with the center line in the width direction of the rolled metal sheet 1 as the bending line. The rolled metal sheet 1 has the rolling anisotropy as described above.

[0026] "Method for manufacturing a diaphragm" By using the rolled metal sheet 1 shown in FIG. 1 and performing punching along the circular contour line 2 shown by the solid line in FIG. 1, a disk-shaped punched material 3 shown in FIG. 2 can be obtained. Then, for the punched material 3, as will be described later, after performing primary processing based on FIG. 3 and then performing secondary processing based on FIG. 4, a diaphragm 5 shown in FIG. 5 can be obtained. In the primary processing, the processing is performed so as to greatly bend the direction TD perpendicular to the rolling direction where the strength is stronger. As an example of this primary processing, a method of bending the punched material 3 into a U shape in the direction TD perpendicular to the rolling direction will be described later. For the punched material 3 subjected to this primary processing, drawing is performed so as to form a partial spherical shell shape in the secondary processing.

[0027] When punching the punched material 3 from the rolled metal sheet 1, assuming the diameter of the contour line 2 overlapping the rolling direction LD as the reference line d as shown in FIG. 2, the punched material is punched so that semicircular arc-shaped notches (identification parts) 3a are formed in the +45° direction in the circumferential direction (clockwise direction) in plan view and the +135° direction in the clockwise direction of the contour line 2, respectively. In the following description, the +45° direction in the clockwise direction will be simply described as the 45° direction, and the +135° direction in the clockwise direction will be simply described as the 135° direction. The example shown in FIG. 1 shows an example in which arc-shaped notches 3a having an inner diameter of about 0.5 to 30% with respect to the diameter of the contour line 2 are formed. Note that the size of the notch 3a is preferably such that an operator handling the diaphragm 5 can visually recognize it, but it is not limited to the above range.

[0028] In this example, the notches 3a are formed in the 45° direction and the 135° direction with respect to the reference line d which is the diameter. However, when the right-handed direction when viewing the contour line 2 in plan view is defined as the positive direction (plus direction: + direction) and the left-handed direction is defined as the negative direction (minus direction: - direction), the notches 3a may be formed in the -45° direction and the -135° direction. In the punched material 3 shown in FIG. 2, the notches 3a formed in the 45° direction and the -135° direction are indicated by solid lines, and the outline of the notches 3a when formed in the -45° direction and the 135° direction is indicated by a two-dot chain line. In FIG. 2, the notch formed in the 45° direction (the first direction) can be referred to as the first notch 3a, the notch formed in the 135° direction (the second direction) can be referred to as the second notch 3a, the notch formed in the -45° direction (the third direction) can be referred to as the third notch 3a, and the notch formed in the -135° direction (the fourth direction) can be referred to as the fourth notch 3a.

[0029] Also, the notch 3a formed in the punched material 3 may be formed in one or more of the aforementioned 45°, 135°, -45°, and -135° directions. In FIG. 2, a notch 3a in the 45° direction is formed at a position where a chain line a indicating the 45° direction with respect to the reference line d intersects the outer peripheral edge of the punched material 3, and a notch 3a in the 135° direction is formed at a position where a chain line e indicating the 135° direction with respect to the reference line d intersects the outer peripheral edge of the punched material 3. In FIG. 2, a notch 3a in the -45° direction is formed at a position where a chain line c indicating the -45° direction with respect to the reference line d intersects the outer peripheral edge of the punched material 3, and a notch 3a in the -135° direction is formed at a position where a chain line b indicating the -135° direction with respect to the reference line d intersects the outer peripheral edge of the punched material 3.

[0030] When forming two notches 3a in the punched material 3, it is more preferable to form the notches 3a at positions adjacent to each other circumferentially, such as forming the notches 3a in the 45° direction and the -45° direction, forming the notches 3a in the 135° direction and the -135° direction, forming the notches 3a in the 45° direction and the 135° direction, or forming the notches 3a in the -45° direction and the -135° direction. By forming the two notches 3a at positions adjacent to each other circumferentially, even if the punched material 3 is turned over during the bending process in the primary processing, there is an advantage that the positional relationship between the notch 3a, the rolling direction LD, and the direction perpendicular to the rolling direction TD can still be specified.

[0031] When forming the notch 3a in the punched material 3, it is preferable to form the center of the notch 3 within a range of ±6° with respect to the aforementioned 45°, 135°, -45°, and -135° directions. Further, when forming the notch 3a in the punched material 3, it is more preferable to form the center of the notch 3a within a range of ±3° with respect to the aforementioned 45°, 135°, -45°, and -135° directions. For example, when forming the notch 3a in the 45° direction, it is preferable that the notch 3a exists within the range of 45°±6°, and more preferably within the range of 45°± 3°. When forming the notch 3a in the 135° direction, it is preferable that the notch 3a exists within the range of 135°±6°, and more preferably within the range of 135°±3°. For example, when forming the notch 3a in the -45° direction, it is preferable that the notch 3a exists within the range of -45°±6°, and more preferably within the range of -45°±3°. When forming the notch 3a in the -135° direction, it is preferable that the notch 3a exists within the range of -135°±6°, and more preferably within the range of -135°±3°. The definition of the notch 3a existing within the aforementioned angular range is that when the notch 3a is in a semi-circular shape, the center of the notch 3a is within the aforementioned angular range. The shape of the notch 3a can adopt various shapes such as a rectangular shape, a triangular shape, a slit shape, etc., but for any shape, as long as its center exists within the aforementioned angular range.

[0032] When the punched material 3 is obtained, a primary process of symmetrically bending the punched material 3 into a U shape is performed, regarding the reference line d of the punched material 3 as the bending center line. Fig. 3(a) shows the relative relationship between the punched material 3 bent into a U shape, the reference line d, and the rolling direction LD. Fig. 3(b) shows the relative relationship between the punched material 3 bent into a U shape, the reference line d, and the direction TD perpendicular to the rolling direction. Note that bending into a U shape is just one example when bending, and other bending shapes such as a V shape are also acceptable. Regarding the bending angle, any angle can be selected according to the material. As shown in Figs. 3(a) and (b), when bending the punched material 3, bending can be performed using a forming jig 6 having a clam-shaped protrusion 6b at the center of the upper surface of a disk-shaped pedestal 6a as illustrated in Fig. 3(c). For example, by aligning the ridge line of the protrusion 6b with the reference line d of the punched material 3, arranging a punch (not shown in detail) having a concave curved surface on the lower surface above the punched material 3, and lowering the punch, accurate bending can be achieved.

[0033] To align the ridge line of the protrusion 6b with the reference line d of the punched material 3, when the cutouts 3a are provided in the 45° direction and the 135° direction, since the outer peripheral edge of the upper surface of the pedestal 6a draws a circle, marks such as imprints are provided on the 45°-direction outer peripheral edge and the 135°-direction outer peripheral surface of the upper surface of the pedestal 6a respectively, and these imprints can be aligned with the aforementioned cutouts 3a. Thereby, the ridge line of the protrusion 6b and the reference line d of the punched material 3 can be accurately aligned. When the cutouts 3a are provided in the -45° direction and the -135° direction, since the outer peripheral edge of the upper surface of the pedestal 6a draws a circle, marks such as imprints are provided on the -45°-direction outer peripheral edge and the -135°-direction outer peripheral edge of the upper surface of the pedestal 6a respectively, and these imprints can be aligned with the aforementioned cutouts 3a. Thereby, the ridge line of the protrusion 6b and the reference line d of the punched material 3 can be accurately aligned. When the cutout 3a is provided in only one of the 45° direction, 135° direction, -45° direction, and -135° directions in the punched material 3, when aligning the position of the mark on the outer peripheral edge of the upper surface of the pedestal 6a with the cutout 3a, it is preferable to provide a mark on the pedestal 6a so that the reference line d of the punched material 3 coincides with the ridge line of the protrusion 6b.

[0034] If the primary processing of bending the punched material 3 is carried out, then the secondary processing by drawing is carried out next. In the drawing process, the receiving member 9 and the rubber plate 10 are accommodated in the recess 8 formed in the holder 7 of the press shown in FIG. 4, and the U-shaped punched material 3 is set on the rubber plate 10. Above the holder 7 of the press, a rod-shaped punch 11 that can be inserted into the recess 8 is provided. On the lower surface of the punch 11, a concave curved surface 11a for processing the spherical shell shape of the target diaphragm 5 is formed.

[0035] On the upper surface of the receiving member 9, a protruding curved surface 9a for forming the target spherical shell shape is formed. The rubber plate 10 has a concave curved surface 10a that adheres to the protruding curved surface 9a on the lower surface side, and a convex curved surface 10b having a shape similar to the aforementioned protruding curved surface 9a on the upper surface side. As shown in FIG. 4, the punched material 3 that has been bent is placed on the upper surface side of the rubber plate 10 so as to be reverse U-shaped. The concave curved surface of the bent punched material 3 faces downward, and the punched material 3 is placed so that the convex curved surface of the punched material 3 faces upward. From this state, the punch 11 is inserted into the recess 8 of the holder 7 from above, and the punched material 3 is pressed against the rubber plate 10 with the concave curved surface 11a of the punch 11 for drawing. By this drawing, the U-shaped punched material 3 can be deformed to obtain a dome-shaped diaphragm 5 having the spherical shell shape shown in FIG. 5. This diaphragm 5 has a partial spherical shell shape having a predetermined diameter D and a predetermined height H.

[0036] In the bending process described with reference to FIG. 3, the diaphragm 5 manufactured as described above accurately aligns the reference line d of the punched material 3 and the ridge line of the protrusion 6b of the forming jig 6 and bends it into a U-shape. Moreover, the formation position of the notch 3a is not in the rolling direction LD or the direction perpendicular to the rolling direction TD of the punched material 3, but in the 45° direction and the 135° direction, which are intermediate positions between the rolling direction LD and the direction perpendicular to the rolling direction TD. As described above, the rolled metal sheet 1 that is the base of the punched material 3 is formed from a metal material having rolling anisotropy, and the metal material forming the rolled metal sheet 1 has a shape in which its crystal grains are stretched in the rolling direction. In the punched material 3 punched from such a rolled metal sheet 1, if a notch 3a is present in the rolling direction LD or the direction perpendicular to the rolling direction TD, due to the aforementioned rolling anisotropy, when the drawing process shown in FIG. 4 is performed, the resulting diaphragm 5 will be distorted and a spherical shell shape of the desired shape cannot be obtained.

[0037] On the other hand, if the notch 3a is provided in the 45° direction and 135° direction as intermediate positions, which are neither the rolling direction LD nor the direction perpendicular to the rolling direction TD, the distortion generated in the diaphragm can be minimized. As a result, a diaphragm 5 with less distortion can be manufactured. Furthermore, by suppressing the variation in the formation position of the notch 3a formed in the punched material 3, a diaphragm with suppressed variation in the secondary forming height after the drawing process can be obtained. For example, if the formation position of the notch 3a formed in the punched material 3 is within the range of 45° ± 6°, 135° ± 6°, -45° ± 6°, or -135° ± 6°, the displacement of the height H of the diaphragm 5 after the drawing process can be reduced to within 15%. Also, if the formation position of the notch 3a formed in the punched material 3 is within any of the ranges of 45° ± 3°, 135° ± 3°, -45° ± 3°, or -135° ± 3°, the displacement of the height H of the diaphragm 5 after the drawing process can be reduced to within 8%.

[0038] In the embodiment described with reference to FIGS. 1 to 5, the notch 3a is adopted as an example of the identification portion, but the identification portion may be an orientation flat or an identification mark such as printing. In the case of an orientation flat, it is sufficient if the center position in the width direction of the orientation flat is within the aforementioned angular range.

[0039] "Second Embodiment" FIG. 6 shows a diaphragm 15 according to the second embodiment of the present invention. The diaphragm 15 in this example has a dome portion 15a having a partial spherical shell shape and a ring-shaped flange portion 15b formed on the outer peripheral edge of the dome portion 15a. In the diaphragm 15 of the second embodiment, notches 15c, 15c are formed on the outer peripheral edge of the flange portion 15b.

[0040] When the diaphragm 15 is viewed in plan, the position where the notch 15c is formed is regarded as a reference line having a diameter that coincides with the rolling direction LD in the diaphragm 15. When the clockwise direction in plan is defined as the + direction and the counterclockwise direction in plan is defined as the - direction, it is the same direction as in the previous embodiment. For example, in the flange portion 15b viewed in plan, one or more directions among the four directions of 45°, 135°, -45°, and -135° can be adopted. In the case of a combination of two directions, it is preferable to form the notches 15c in the 45° direction and the -45° direction, and it is preferable to form the notches 15c in the 135° direction and the -135° direction. The diaphragm 15 shown in FIG. 6 shows an example in which notches 15c are formed in the -135° direction and the 135° direction.

[0041] When manufacturing the diaphragm 15 of the second embodiment, in the same manner as when punching out the punching material 3 from the rolled metal sheet 1 shown in FIG. 1, a wide punching material including the flange portion 15b is punched out from the rolled metal sheet 1. With respect to this punching material, it is bent into a U shape including the flange portion in the same manner as described with reference to FIG. 3, and the punched material with a flange after the bending process is accommodated in the recess of a press having a structure similar to the structure shown in FIG. 4. In the recess of the press in this case, a receiving member having a ring-shaped flat end portion corresponding to the width of the flange portion on the outer periphery and a rubber plate are arranged, and it may be pressed with a punch having a ring-shaped flat end portion corresponding to the width of the flange portion on the outer periphery.

[0042] Also in the diaphragm 15 of the second embodiment, by using the notches 15c, an accurate U-shaped bending can be performed in the primary processing. Even if a punched material with a flange from the rolled metal sheet 1 having rolling anisotropy is used, a diaphragm 15 having a spherical shell shape with little height ratio variation and little distortion in the circumferential direction can be obtained by the drawing process of the secondary processing.

Example

[0043] A metal disc (punching material) with an outer diameter of 26 mm was punched out from a rolled metal sheet (thickness: 0.2 mm) made of a Co-Ni based alloy (trade name SPRON510 (SPRON: registered trademark) of Seiko Instruments Inc.). When punching the metal disc, with respect to the rolling direction (reference line) on the surface of the rolled metal sheet, the clockwise direction in plan view is defined as the + direction, and the counterclockwise direction in plan view is defined as the - direction. A metal disc with a flange was punched out so as to have notches in the 135° direction and the -135° direction with respect to the reference line. The outer diameter of the flange is 26 mm, and the inner diameter of the flange is 24 mm. And the notch is formed in an arc shape with a radius of 1 mm centering on a position 13.7 mm away from the center of the metal disc in the outer peripheral direction in plan view. Regarding the punched metal disc, since it has notches in the 135° direction and the -135° direction with respect to the reference line, the reference line (rolling direction) can be accurately defined for each of the punched metal discs. Next, the metal disc is subjected to a primary processing of bending it into a U shape. For the bending process, a forming jig 6 having a protrusion 6b on a pedestal 6a shown in Fig. 3(c) is used, and the ridge line of the protrusion 6b and the reference line are accurately aligned, and a primary processing of bending the metal disc into a U shape is performed. By this primary processing, the metal disc can be symmetrically bent into a U shape with the reference line that coincides with the rolling direction of the metal disc as the bending center line.

[0044] Next, the metal disc bent into a U shape was set in a press machine equipped with a holder 7 shown in Fig. 4. Specifically, a receiving member 9 and a rubber plate 10 were housed in a recess 8 formed in the holder 7, and the U-shaped metal disc (punching material) 3 was set on the rubber plate 10. The metal disc was arranged with the protrusion side facing upward and the recess side facing downward. A secondary processing of squeezing the U-shaped metal disc was performed using a rod-shaped punch 11 that can be inserted into the recess 8 to manufacture a diaphragm with a flange having a shape shown in Fig. 6 having a partial spherical shell shape. In order to investigate the formation position of the notch and the influence of the primary processing and the secondary processing, the angle formed between the ridge line of the protrusion 6b and the reference line (bending center line) of the metal disk during the primary processing was changed, and the influence after the secondary processing was examined.

[0045] The forming jig 6 used for the primary processing uses a press machine having the same shape as the press machine provided with the holder 7 having the recess 8 shown in FIG. 4. The forming jig 6 is set in the recess 8, and the bending process of the primary processing is performed. In this case, if the orientation of the metal disk with respect to the recess 8 of the forming jig 6 is changed, the angle can be easily changed. In the following description, when the forming jig 6 is set in the recess of the press machine and the bending process is performed, the filling angle of the metal disk with respect to the forming jig is changed as shown in Table 1 below, and the angle formed between the ridge line of the protrusion 6b and the rolling direction (reference line) of the metal disk in the primary processing is changed to perform a bending test. In Table 1 below, the angle formed between the filling direction of the metal disk and the rolling direction (reference line) in the metal disk is denoted as the filling angle.

[0046] The secondary forming height was measured for each diaphragm manufactured by changing the filling angle. For the secondary forming height, it was measured as the height including the plate thickness of 0.1 mm of the metal disk constituting the diaphragm, and is shown in Table 1 below. FIG. 7 shows the relationship in each direction when the filling angle is set to minus (−), and FIG. 8 shows the relationship in each direction when the filling angle is set to plus (+).

[0047] In FIG. 7, in the circle when the metal disk is viewed in plan view, the 0° direction is regarded as the normal forming jig filling direction, and the metal disk is filled and installed in the recess of the forming jig so that the rolling direction of the metal disk (denoted as the MD rolling direction in FIG. 7) is rotated by a predetermined angle in the minus direction (counterclockwise direction). The diaphragm obtained was viewed in plan view, the height (mm) was obtained with the +45° direction as the measurement direction (+), and the height (mm) was obtained with the -45° direction as the measurement direction (−). Fig. 8 shows a case where a metal disk is filled and placed in the concave portion of a forming jig so that, in a circle when the metal disk is viewed in plan view, with the 0° direction regarded as the normal forming jig filling direction, the rolling direction of the metal disk (indicated as the MD rolling direction in Fig. 8) is rotated by a predetermined angle in the plus direction (clockwise direction). The height (mm) was determined with the +45° direction as the measurement direction (+) when the obtained diaphragm was viewed in plan view, and the height (mm) was determined with the -45° direction as the measurement direction (-).

[0048] In the case of the negative filling angle shown in Fig. 7 and the case of the positive filling angle shown in Fig. 8, a filling angle of any one of -30°, -20°, -10°, -6°, -3°, 0°, +3°, +6°, +10°, +20°, +30° was selected. The shape difference can be grasped by obtaining the height in the measurement direction (-) in the obtained diaphragm, obtaining the height in the measurement direction (+) in the obtained diaphragm, and calculating their ratio (measurement direction (-) / measurement direction (+)). The above results are summarized and described in Table 1 below.

[0049]

Table 1

[0050] Also, regarding the results obtained as shown in Table 1, the relationship between the filling angle (°) and the secondary forming height is shown in Fig. 9, and the relationship between the filling angle and the height ratio is shown in Fig. 10.

[0051] From the results shown in Table 1, Fig. 9, and Fig. 10, it was found that when a metal disk with a flange having a notch in the direction ±135° with respect to the rolling direction (reference line) punched out from a rolled metal sheet is bent in the primary processing, depending on the direction, the diaphragm obtained after the secondary processing can be accurately drawn and formed. As shown in Table 1 and Fig. 9, it was found that the variation in the secondary forming height can be reduced by adjusting the angular difference between the reference line indicating the rolling direction of the metal disk and the bending center line during the primary forming so that the filling angle is in the range of 0 ± 6°. Also, it was found that when the filling angle is in the range of 0 ± 3°, the variation in the secondary forming height can be minimized.

[0052] As shown in Table 1 and Fig. 10, it was found that the variation in the height ratio of the diaphragm can be reduced to within 15% by adjusting the angular difference between the reference line indicating the rolling direction of the metal disk and the bending center line during the primary forming so that the filling angle is in the range of 0 ± 6°. Also, it was found that when the above-mentioned angular difference is adjusted so that the filling angle is in the range of 0 ± 3°, the variation in the height ratio of the diaphragm can be reduced to within 8%. Note that when the diaphragm with a flange portion manufactured with the filling angle in the range of 0 ± 6° is placed on a flat surface such as a desk with the flange portion facing down, no rattling occurs in the diaphragm even when the diaphragm is pressed with a finger. In contrast, when the diaphragm manufactured with the filling angle in the range of 0 ± 10°, 0 ± 20°, or 0 ± 30° is placed on a flat surface such as a desk with the flange portion facing down, distinct rattling occurs when the diaphragm is pressed with a finger.

Explanation of Signs

[0053] 1…Rolled metal plate, 2…Contour line, 3…Punched material, 3a…Notch, 5…Diaphragm, 7…Holder, 8…Recess, 9…Receiving member, 10…Rubber plate, 11…Punch, 15…Diaphragm, 15a…Dome portion, 15b…Flange portion, 15c…Notch, d…Reference line, H…Height, D…Diameter, LD…Rolling direction, TD…Direction perpendicular to rolling.

Claims

1. A diaphragm made of a punched material of a rolled metal sheet having rolling anisotropy and having a partial spherical shell shape, a first direction that is 45° ± 6° from the rolling direction of the rolled metal sheet around the circumference in a plan view of the partial spherical shell shape, a second direction that is 135° ± 6° around the circumference in a plan view of the partial spherical shell shape, a third direction that is -45° ± 6° around the circumference in a plan view of the partial spherical shell shape, and a fourth direction that is -135° ± 6° around the circumference in a plan view of the partial spherical shell shape, the diaphragm being characterized by having an identification portion in at least one of the directions.

2. The diaphragm according to claim 1, wherein the first direction is 45° ± 3° around the circumference in a plan view, the second direction is 135° ± 3° around the circumference in a plan view, the third direction is -45° ± 3° around the circumference in a plan view, and the fourth direction is -135° ± 3° around the circumference in a plan view.

3. The diaphragm according to claim 1 or claim 2, characterized by having an identification portion in the first direction and the second direction, or having an identification portion in the third direction and the fourth direction.

4. The diaphragm according to claim 1 or claim 2, wherein the identification portion is a notch or an orientation flat.

5. The diaphragm according to claim 1 or claim 2, wherein the rolled metal sheet is made of any one of a Co-Ni based alloy, stainless steel, a Ni-Mo-Cr based alloy, a Ni-Cr based alloy, and a Ni based alloy.

6. When punching a rolled metal sheet having rolling anisotropy to form a punched material, performing a primary process of bending the punched material symmetrically with a straight line parallel to the rolling direction as a center line, and then performing a secondary process of forming a diaphragm having a partial spherical shell shape by drawing, after forming the punched material by punching the rolled metal sheet so as to have an identification portion in at least one of a first direction that is 45° ± 6° from the rolling direction of the rolled metal sheet around the circumference in a plan view of the partial spherical shell shape, a second direction that is 135° ± 6° around the circumference in a plan view of the partial spherical shell shape, a third direction that is -45° ± 6° around the circumference in a plan view of the partial spherical shell shape, and a fourth direction that is -135° ± 6° around the circumference in a plan view of the partial spherical shell shape, A method for manufacturing a diaphragm, characterized in that the primary processing is performed on the punched material using a straight line parallel to the rolling direction recognized with the identification portion as a bending center line. **Claim 7** The method for manufacturing a diaphragm according to claim 6, wherein the first direction is a direction of 45° ± 3° around the plane view, the second direction is a direction of 135° ± 3° around the plane view, the third direction is a direction of -45° ± 3° around the plane view, and the fourth direction is a direction of -135° ± 3° around the plane view. **Claim 8** The method for manufacturing a diaphragm according to claim 6 or 7, characterized in that an identification portion is formed in the first direction and the second direction, or an identification portion is formed in the third direction and the fourth direction. **Claim 9** The method for manufacturing a diaphragm according to claim 6 or 7, characterized in that a notch or an orientation flat is formed as the identification portion. **Claim 10** The method for manufacturing a diaphragm according to claim 6 or 7, characterized in that any one of a Co-Ni-based alloy, stainless steel, a Ni-Mo-Cr-based alloy, a Ni-Cr-based alloy, and a Ni-based alloy is used as the metal material constituting the rolled metal sheet.

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