Metal diaphragm and method for manufacturing same

Abstract

A metal diaphragm according to the present invention comprises a punched member of a rolled metal sheet made of a metal having rolling anisotropy, and has a partially spherical shell shape. The metal diaphragm is characterized by having an identification part located in at least one of a first direction that is a 45°±6° direction around the circumference of the partially spherical shell shape, a second direction that is a 135°±6° direction around the circumference of the partially spherical shell shape, a third direction that is a -45°±6° direction around the circumference of the partially spherical shell shape, and a fourth direction that is a -135°±6° direction around the circumference of the partially spherical shell shape, all with respect to the rolling direction of the rolled metal sheet.

Description

Metal diaphragm and its manufacturing method

[0001] The present invention relates to a metal diaphragm and a manufacturing method thereof. This application claims priority to Japanese Patent Application No. 2024-007920, filed on January 23, 2024, the contents of which are incorporated herein by reference.

[0002] Diaphragms used in clean valves generally require high elasticity, so metal sheets with a high degree of cold rolling are used. Because these metal sheets have rolling anisotropy, the desired partial spherical shell shape cannot be obtained by simply pressing the material to form a concave spherical shape through drawing. To obtain the partial spherical shell shape, drawing must be performed using a die shape that takes rolling anisotropy into account. During this process, it is necessary to identify the rolling direction of the metal sheet. Possible methods for identifying the rolling direction include providing an identification mark on the metal sheet by printing, etching, notching, or the like.

[0003] The following Patent Document 1 discloses a technique for forming a notch along the rolling direction in a metal plate material. The following Patent Document 2 discloses a technique for forming an orientation flat along the rolling direction in a metal plate material.

[0004] JP-A No. 09-014441 JP-A No. 09-248631

[0005] The drawing of highly elastic metal sheets requires sufficient processing precision, and in particular, it is necessary to minimize the deviation of the drawing position relative to the rolling direction of the metal sheet. 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 direction. Furthermore, when a notch or an orientation flat is formed in the rolling direction or the direction perpendicular thereto, there is a problem that distortion is likely to occur in the partial spherical shell shape after forming in the case of highly elastic metal sheets that have rolling anisotropy.

[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.

[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 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 rolled metal plate having rolling anisotropy, an identifier is provided in one 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, and then the drawing can be performed. By correctly selecting the bending direction and then 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 identifier is not easy, and if the bending direction is incorrect, a metal diaphragm having the desired partial spherical shell shape cannot be obtained. Furthermore, the direction of bending can be determined by providing an identifier in the rolling direction or perpendicular to the rolling direction. However, if an identifier such as a notch or an orientation flat is provided in the rolling direction or perpendicular to the rolling direction, stress is applied to the punched material during drawing, causing distortion of the partial spherical shell shape starting from the identifier such as the notch or the orientation flat. Distortion that occurs in the partial spherical shell shape becomes an undesirable defect in the diaphragm, which is a precision part, so providing an identification portion in any of the first to fourth directions mentioned above contributes to the formation of a partial spherical shell shape without distortion.

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

[0010] Preferably, the first direction is 45°±3°, the second direction is 135°±3°, the third direction is −45°±3°, and the fourth direction is −135°±3°. By selecting these directions, a metal diaphragm with a partial spherical shell shape that has less distortion can be obtained.

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

[0012] If the punched material has an identifying portion in the first direction and the second direction, or an identifying portion in the third direction and the fourth direction, the bending direction when bending the punched material can be reliably and easily set, thereby making it possible to reliably and easily obtain a diaphragm having a distortion-free partial spherical shell shape.

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

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

[0015] (5) In the metal diaphragm according to one aspect of the present invention, it is preferable that the rolled metal plate 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 steel, Ni-Mo-Cr-based alloys, Ni-Cr-based alloys, and Ni-based alloys are all metals that have high elasticity and rolling anisotropy, and metal diaphragms made of these metals can provide diaphragms that are highly elastic and have excellent responsiveness.In addition, these metals also have excellent corrosion resistance, so it is possible to provide diaphragms that have excellent corrosion resistance.

[0017] (6) A method for manufacturing a metal diaphragm according to one aspect of the present invention is characterized in that, when a secondary processing is performed to form a diaphragm having a partial spherical shell shape by drawing, the punched material is formed by punching the rolled metal plate having rolling anisotropy to form a punched material, and the punched material is subjected to a primary processing of symmetrically bending the punched material around a straight line parallel to the rolling direction as a center line, the punched material is formed by punching the rolled metal plate so as to have an identification portion in at least one of 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, and the punched material is then subjected to the primary processing, with the straight line parallel to the rolling direction, recognized as a mark using the identification portion, as a bending center line.

[0018] In a method for manufacturing a metal diaphragm made from a punched material of a rolled metal plate having rolling anisotropy, an identification part is provided in one of the first to fourth directions, and 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 subsequent drawing. By correctly selecting the bending direction and then 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 bending direction is incorrect, a metal diaphragm having the desired partial spherical shell shape cannot be obtained.

[0019] Furthermore, the directionality during bending can also be determined by providing an identifier in the rolling direction or perpendicular to the rolling direction. However, if an identifier such as a notch or orientation flat is provided in the rolling direction or perpendicular to the rolling direction, stress is applied to the punched material during drawing, starting from the identifier such as the notch or orientation flat, causing distortion in the partial spherical shell shape. Distortion in the partial spherical shell shape is an undesirable defect in a diaphragm, which is a precision part. Therefore, by providing an identifier in any of the first to fourth directions described above, a diaphragm having a partial spherical shell shape without distortion can be formed.

[0020] (7) In a method for manufacturing a metal diaphragm according to one aspect of the present invention, it is preferable that the first direction is a 45°±3° direction around the circumference in a plan view, the second direction is a 135°±3° direction around the circumference in a plan view, the third direction is a −45°±3° direction around the circumference in a plan view, and the fourth direction is a −135°±3° direction around the circumference in a plan view. (8) In a method for manufacturing a metal diaphragm according to one aspect of the present invention, it is preferable that an identifier be formed in the first direction and the second direction, or that an identifier be formed in the third direction and the fourth direction. (9) In a method for manufacturing a metal diaphragm according to one aspect of the present invention, it is preferable that a notch or an orientation flat be formed as the identifier. (10) In a method for manufacturing a metal diaphragm according to one aspect of the present invention, the metal material constituting the rolled metal plate is 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.

[0021] The metal diaphragm according to the present invention has a configuration in which an identification portion is provided in at least one of the first to fourth directions in a punched material of a rolled metal plate having rolling anisotropy. As a result, when the punched material of the rolled metal plate is bent along the rolling direction and then drawn to obtain a partial spherical shell shape, the bending can be performed in the correct direction and then the drawing can be performed. By performing the bending in the correct direction and then performing the drawing without being affected by the identification portion provided in any of the first to fourth directions, a metal diaphragm having the desired partial spherical shell shape with little distortion can be obtained.

[0022] 1 is a plan view showing an example of punching when punching a punched material that forms the basis of a diaphragm according to a first embodiment from a rolled metal plate; FIG. 2 is a plan view showing an example of a punched material; FIG. 3 is a view showing an example of a diaphragm manufacturing method, in which (a) is a diagram showing the relationship between the punched material bent into a U-shape and the rolling direction, (b) is a diagram showing the relationship between the punched material bent into a U-shape and the direction perpendicular to the rolling, and (c) is a perspective view showing an example of a jig used when bending the punched material into a U-shape; FIG. 4 is a cross-sectional view showing the positional relationship between a mold, a circular plate, and a rubber plate that are used to draw-form the punched material bent into a U-shape; FIG. 5 is a perspective view showing a diaphragm according to a first embodiment, its diameter, and height; FIG. 6 is a perspective view showing a diaphragm according to a second embodiment; FIG. 7 is an explanatory view showing various directions when a circular punched material is placed in a forming jig and the angle (filling angle) by which it is displaced from a specific direction is set to the negative (-) side in the example; 1 is an explanatory diagram showing various directions when a disc-shaped punched material is placed in a molding jig and the angle (filling angle) by which it is displaced relative to a specific direction is set to the plus (+) side in an embodiment; 2 is a graph showing the relationship between the filling angle and the secondary molding height when the filling angle is adjusted to the range of -30° to +30° in an embodiment; and 3 is a graph showing the relationship between the filling angle and the height ratio when the filling angle is adjusted to the range of -30° to +30° in an embodiment.

[0023] Hereinafter, an embodiment of a diaphragm according to the present invention will be described with reference to the drawings. In the following embodiment, a dome-shaped diaphragm having a partial spherical shell shape will be described as an example of a diaphragm. Note that in the drawings used in the following description, the scale of each component is appropriately changed and displayed so that each component can be recognized.

[0024] First Embodiment Fig. 1 shows a strip-shaped rolled metal plate 1, which is made of, for example, a Co-Ni-based alloy, stainless steel, a Ni-Mo-Cr-based alloy, a Ni-Cr-based alloy, or a Ni-based alloy. 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, making them suitable as metal materials for forming metal diaphragms.

[0025] The rolled metal plate 1 is made of any of the aforementioned metal materials, but 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. The rolled metal plate 1 has a thickness of, for example, approximately 0.03 mm to 0.5 mm. Furthermore, because the rolled metal plate 1 is manufactured by rolling the aforementioned metal material, the crystal grains constituting the metal structure of the rolled metal plate 1 are elongated in the rolling direction. Therefore, when comparing the strength of the rolled metal plate 1 in the rolling direction with the strength in the direction perpendicular to the rolling (width direction: TD), the strength in the direction perpendicular to the rolling is higher. In other words, the strength when the rolled metal plate 1 is bent with both ends at the front and rear of the rolling direction and a straight line perpendicular to the width direction as a bending line is higher than the strength when the rolled metal plate 1 is bent symmetrically with the width-direction center line of the rolled metal plate 1 as a bending line. The rolled metal plate 1 has the rolling anisotropy described above.

[0026] "Method for manufacturing a metal diaphragm" Using a rolled metal plate 1 shown in FIG. 1, a disk-shaped punched material 3 shown in FIG. 2 can be obtained by punching along a circular outline 2 shown by a solid line in FIG. 1. Then, as will be described later, the punched material 3 is subjected to a primary processing based on FIG. 3 and then a secondary processing based on FIG. 4 to obtain a metal diaphragm 5 shown in FIG. 5. In the primary processing, the punched material 3 is bent significantly in the direction perpendicular to the rolling direction TD, where the strength is greater. As an example of this primary processing, a method of bending the punched material 3 into a U-shape in the direction perpendicular to the rolling direction TD will be described later. In the secondary processing, the punched material 3 that has been subjected to this primary processing is drawn to have a partial spherical shell shape.

[0027] When punching a punched material 3 from a rolled metal sheet 1, the diameter of the contour line 2 that overlaps the rolling direction LD is assumed to be the reference line d, as shown in FIG. 2 . The contour line 2 is punched so as to form semicircular arc-shaped notches (identification features) 3a in the +45° direction and the +135° direction in the clockwise direction in a plan view. In the following description, the +45° direction in the clockwise direction will be simply referred to as the 45° direction, and the +135° direction in the clockwise direction will be simply referred to as the 135° direction. The example shown in FIG. 1 illustrates an example in which an arc-shaped notch 3a is formed with an inner diameter of approximately 0.5 to 30% of the diameter of the contour line 2. The size of the notch 3a is preferably large enough to be visible to an operator handling the metal diaphragm 5, but is not limited to the aforementioned range.

[0028] In this example, the notches 3a are formed in the 45° and 135° directions relative to the reference line d, which is the diameter, but the positions at which the notches 3a are formed may also be in the -45° and -135° directions, if the clockwise direction in a plan view of the contour line 2 is defined as the positive direction (plus direction) and the counterclockwise direction as the negative direction (minus direction). In the punched material 3 shown in Figure 2, the notches 3a formed in the 45° and -135° directions are shown by solid lines, and the outlines of the notches 3a when formed in the -45° and 135° directions are shown by two-dot chain lines. In FIG. 2, the notch formed in the 45° direction (first direction) can be referred to as the first notch 3a, the notch formed in the 135° direction (second direction) can be referred to as the second notch 3a, the notch formed in the −45° direction (third direction) can be referred to as the third notch 3a, and the notch formed in the −135° direction (fourth direction) can be referred to as the fourth notch 3a.

[0029] Furthermore, the notches 3a formed in the punched material 3 may be formed in one or more of the 45°, 135°, −45°, and −135° directions. In Figure 2, a (first) 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 with the outer peripheral edge of the punched material 3, and a (second) 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 with the outer peripheral edge of the punched material 3. In Figure 2, a (third) 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 with the outer peripheral edge of the punched material 3, and a (fourth) 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 with the outer peripheral edge of the punched material 3.

[0030] When two notches 3a are formed in the punched material 3, it is more preferable to form the notches 3a at adjacent positions around the circumference, such as forming the notches 3a in the 45° and −45° directions, or forming the notches 3a in the 135° and −135° directions, or forming the notches 3a in the 45° and 135° directions, or forming the notches 3a in the −45° and −135° directions. Forming the two notches 3a at adjacent positions around the circumference has the advantage that even if the punched material 3 is turned over during bending in the primary processing, the positional relationship between the notches 3a and the rolling direction LD and the transverse to rolling direction TD can still be specified.

[0031] When forming the notches 3a in the punched material 3, it is preferable to form the notches 3 so that the centers of the notches 3 lie within a range of ±6° with respect to the aforementioned 45°, 135°, −45°, and −135° directions. Furthermore, when forming the notches 3a in the punched material 3, it is more preferable to form the notches 3a so that the centers of the notches 3a lie within a range of ±3° with respect to the aforementioned 45°, 135°, −45°, and −135° directions. For example, when forming the (first) notches 3a in the 45° direction, it is preferable that the (first) notches 3a exist within a range of 45° ±6°, and it is more preferable that the (first) notches 3a exist within a range of 45° ±3°. When the (second) notch 3a is formed in the 135° direction, it is preferable that the (second) notch 3a be present in the range of 135°±6°, and more preferably in the range of 135°±3°. For example, when the (third) notch 3a is formed in the −45° direction, it is preferable that the (third) notch 3a be present in the range of −45°±6°, and more preferably in the range of −45°±3°. When the (fourth) notch 3a is formed in the −135° direction, it is preferable that the (fourth) notch 3a be present in the range of −135°±6°, and more preferably in the range of −135°±3°. The presence of the notch 3a within the aforementioned angular range is defined as the case where the notch 3a is semicircular and the center of the notch 3a is within the aforementioned angular range. The shape of the notch 3a can be various shapes such as a rectangle, a triangle, a slit, etc., but whatever the shape, it is only necessary that the center of the notch 3a is within the above-mentioned angle range.

[0032] Once the punched material 3 is obtained, the primary process involves bending the punched material 3 symmetrically into a U-shape, with the reference line d of the punched material 3 regarded as the folding center line. Figure 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. Figure 3(b) shows the relative relationship between the punched material 3 bent into a U-shape, the reference line d, and the rolling direction TD. Note that bending into a U-shape is just one example; other bending shapes such as a V-shape are also acceptable, and the bending angle can be selected arbitrarily depending on the material. When bending the punched material 3 as shown in Figures 3(a) and (b), the bending process can be performed using a forming jig 6 having a semi-cylindrical protrusion 6b at the center of the top surface of a disk-shaped base 6a, as shown in Figure 3(c). For example, accurate bending processing can be achieved by aligning the ridge line of the protrusion 6b with the reference line d of the punched material 3, placing a punch (not shown) with a concave curved surface on its underside above the punched material 3, and then lowering the punch.

[0033] To align the ridge line of the protrusion 6b with the reference line d of the punched material 3, when the notches 3a are provided in the 45° and 135° directions, since the outer peripheral edge of the upper surface of the base 6a forms a circle, marks such as engravings can be provided on the outer peripheral edge of the upper surface of the base 6a in the 45° and 135° directions, respectively, and these marks can be aligned with the notches 3a mentioned above. This allows for accurate alignment of the ridge line of the protrusion 6b with the reference line d of the punched material 3. When the notches 3a are provided in the -45° and -135° directions, since the outer peripheral edge of the upper surface of the base 6a forms a circle, marks such as engravings can be provided on the outer peripheral edge of the upper surface of the base 6a in the -45° and -135° directions, respectively, and these marks can be aligned with the notches 3a mentioned above. This allows for accurate alignment of the ridge line of the protrusion 6b with the reference line d of the punched material 3. When the cutout portion 3a is provided in only one of the 45°, 135°, -45° and -135° directions in the punched material 3, it is preferable to provide the mark on the base 6a so that when the position of the mark on the outer peripheral edge of the upper surface of the base 6a is aligned with the cutout portion 3a, the reference line d of the punched material 3 coincides with the ridge line of the protrusion 6b.

[0034] After the primary process of bending the punched material 3 has been performed, the secondary process of drawing is then performed. In the drawing process, a receiving member 9 and a rubber plate 10 are placed in a recess 8 formed in a holder 7 of a press machine shown in Figure 4, and the U-shaped punched material 3 is set on top of the rubber plate 10. A rod-shaped punch 11 that can be inserted into the recess 8 is provided above the holder 7 of the press machine. The underside of the punch 11 is formed with a concave curved surface 11a for processing the desired spherical shell shape of the metal diaphragm 5.

[0035] The upper surface of the receiving member 9 is formed with a convex surface 9a for forming the desired spherical shell shape. The rubber plate 10 has a concave surface 10a on its lower surface that is in close contact with the convex surface 9a, and a convex surface 10b on its upper surface that is similar in shape to the convex surface 9a. As shown in FIG. 4 , the bent punched material 3 is placed on the upper surface of the rubber plate 10 so as to form an inverted U-shape. The bent punched material 3 is placed with its concave surface facing downward and its convex surface facing upward. From this state, a punch 11 is inserted from above into the recess 8 of the holder 7, and the concave surface 11a of the punch 11 presses the punched material 3 against the rubber plate 10 to perform a drawing process. This drawing process deforms the U-shaped punched material 3, resulting in a dome-shaped metal diaphragm 5 having a spherical shell shape as shown in FIG. 5 . This metal diaphragm 5 has a partial spherical shell shape with a predetermined diameter D and a predetermined height H.

[0036] The metal diaphragm 5 manufactured as described above is bent into a U-shape in the bending process described with reference to Figure 3 by accurately aligning the reference line d of the punched material 3 with the ridge line of the protrusion 6b of the forming jig 6. Furthermore, the positions of the cutouts 3a are neither in the rolling direction LD of the punched material 3 nor in the direction transverse to the rolling direction TD, but in the 45° and 135° directions that are intermediate between the rolling direction LD and the direction transverse to the rolling direction TD. As described above, the rolled metal plate 1 that is the base of the punched material 3 is made of a metal material that has rolling anisotropy, and the metal material that forms the rolled metal plate 1 has a shape in which its crystal grains are elongated in the rolling direction. If a notch 3 a exists in the rolling direction LD or the direction perpendicular to the rolling direction TD in the punched material 3 punched out from such a rolled metal plate 1, the above-mentioned rolling anisotropy will cause distortion in the resulting metal diaphragm 5 when the drawing process shown in FIG. 4 is performed, and the desired spherical shell shape will not be obtained.

[0037] In contrast, if the notches 3a are provided at intermediate positions, namely, the 45° and 135° directions, which are neither in the rolling direction LD nor in the direction perpendicular to the rolling direction TD, the distortion of the metal diaphragm can be minimized, resulting in the manufacture of a metal diaphragm 5 with little distortion. A metal diaphragm 5 with little distortion can be stably installed without rattle when placed on a flat surface such as a desk in the state shown in FIG. 5 . In other words, the low distortion reduces the height difference around the bottom edge of the metal diaphragm 5, allowing the metal diaphragm 5 to be placed on a flat surface without rattle. Furthermore, by reducing the variation in the position of the notches 3a formed in the punched material 3, a metal diaphragm can be obtained with reduced variation in the secondary forming height after drawing. For example, if the position of the cutout 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 metal diaphragm 5 after drawing can be reduced to within 15%. Also, if the position of the cutout 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 metal diaphragm 5 after drawing can be reduced to within 8%.

[0038] 1 to 5, the notch 3a is used as an example of the identifying portion, but the identifying portion may be an orientation flat or an identifying mark such as a print. In the case of an orientation flat, it is sufficient that the center position of the orientation flat in the width direction is within the above-mentioned angle range.

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

[0040] The positions of the notches 15c are the same as those in the previous embodiment, assuming that the diameter of the metal diaphragm 15 that coincides with the rolling direction LD is the reference line, and the clockwise direction in plan view is defined as the + direction and the counterclockwise direction in plan view as the - direction. For example, in the plan view of the flange 15b, one or more of the four directions of 45°, 135°, −45°, and −135° can be adopted. When two directions are combined, it is preferable to form the notches 15c in the 45° and −45° directions, and it is preferable to form the notches 15c in the 135° and −135° directions. The metal diaphragm 15 shown in FIG. 6 shows an example in which the notches 15c are formed in the −135° and 135° directions.

[0041] When manufacturing the metal diaphragm 15 of the second embodiment, a wide punched material having a width including the flange 15b is punched out from the rolled metal plate 1 in the same manner as when the punched material 3 is punched out from the rolled metal plate 1 shown in Fig. 1. This punched material is bent into a U-shape including the flange, as in the case described with reference to Fig. 3, and the flanged punched material after the bending process is placed in a recess of a press machine having a structure similar to that shown in Fig. 4. In this case, a receiving member having a ring-shaped flat end on its outer periphery corresponding to the width of the flange and a rubber plate are placed in the recess of the press machine, and the punch is pressed with a punch having a ring-shaped flat end on its outer periphery corresponding to the width of the flange.

[0042] The metal diaphragm 15 of the second embodiment also utilizes the notches 15c, 15c to enable accurate U-shaped bending in the primary process. If a flanged punched material is used from a rolled metal plate 1 with rolling anisotropy, a metal diaphragm 15 having the desired spherical shell shape with little circumferential variation in height ratio and little distortion can be obtained by the secondary drawing process. A metal diaphragm 15 with little distortion can be stably installed without rattle when placed on a flat surface such as a desk in the state shown in Figure 6. In other words, the little distortion means that the height difference between the bottom surface of the flange 15b in the metal diaphragm 15 is small, and the metal diaphragm 15 can be placed on a flat surface without rattle.

[0043] A metal disk (punched material) having an outer diameter of 26 mm was punched out from a rolled metal plate (thickness: 0.2 mm) made of a Co—Ni-based alloy (Seiko Instruments Inc., trade name SPRON510 (SPRON: registered trademark)). When punching out the metal disk, the clockwise direction in plan view relative to the rolling direction (reference line) of the surface of the rolled metal plate was defined as the + direction, and the counterclockwise direction in plan view relative to the rolling direction (reference line) of the surface of the rolled metal plate was defined as the - direction. A metal disk with a flange was punched out so as to have notches in the 135° direction and the -135° direction relative to the reference line. The flange had an outer diameter of 26 mm and an inner diameter of 24 mm. The notch was formed in an arc shape with a radius of 1 mm, centered at a position 13.7 mm away from the center of the metal disk in plan view in the outer circumferential direction. Since the punched metal disks have notches at 135° and -135° with respect to the reference line, the reference line (rolling direction) can be accurately determined for each punched metal disk. Next, the metal disks are subjected to a primary bending process to bend them into a U-shape. For the bending process, a forming jig 6 having a protrusion 6b on a base 6a shown in FIG. 3(c) is used, and the ridge line of the protrusion 6b is accurately aligned with the reference line, and the primary bending process is performed to bend the metal disk into a U-shape. This primary bending process allows the metal disks to be symmetrically bent into a U-shape, with the reference line coinciding with the rolling direction of the metal disk as the folding center line.

[0044] Next, the U-shaped metal disk was placed in a press equipped with a holder 7 shown in FIG. 4. Specifically, a receiving member 9 and a rubber plate 10 were placed in a recess 8 formed in the holder 7, and a U-shaped metal disk (punched material) 3 was placed on top of the rubber plate 10. The metal disk was positioned with the protrusion facing upward and the recess facing downward. A rod-shaped punch 11 insertable into the recess 8 was used to perform a secondary process of drawing the U-shaped metal disk, producing a diaphragm with a flange having a partial spherical shell shape as shown in FIG. 6. To investigate the effects of the cutout position and the primary and secondary processes, the angle between the ridge line of the protrusion 6b and the reference line (the center line of bending) of the metal disk during the primary process was changed, and the effect after the secondary process was investigated.

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

[0046] The secondary forming height was measured for each metal diaphragm manufactured with different filling angles. The secondary forming height was measured as the height including the 0.1 mm thickness of the metal disc that constitutes the metal diaphragm, and is shown in Table 1 below. Figure 7 shows the relationship between each direction when the filling angle is set to negative (-), and Figure 8 shows the relationship between each direction when the filling angle is set to positive (+).

[0047] Figure 7 shows a case where a metal disk is filled into a recess of a forming jig and placed so that the rolling direction of the metal disk (indicated as the MD rolling direction in Figure 7) is rotated a predetermined angle in the negative direction (counterclockwise) with the 0° direction in a circular plan view of the metal disk as the normal filling direction of the forming jig. The height (mm) of the resulting metal diaphragm was measured with the +45° direction as the measurement direction (+) and the -45° direction as the measurement direction (-). Figure 8 shows a case where a metal disk is filled into a recess of a forming jig and placed so that the rolling direction of the metal disk (indicated as the MD rolling direction in Figure 8) is rotated a predetermined angle in the positive direction (clockwise) with the 0° direction in a circular plan view of the metal disk as the normal filling direction of the forming jig. The height (mm) of the obtained metal diaphragm was measured in a plan view in the +45° direction as the measurement direction (+), and in the −45° direction as the measurement direction (−).

[0048] For the negative filling angle shown in Figure 7 and the positive filling angle shown in Figure 8, filling angles of -30°, -20°, -10°, -6°, -3°, 0°, +3°, +6°, +10°, +20°, and +30° were selected. The shape difference can be determined by determining the height of the resulting metal diaphragm in the measurement direction (-), determining the height of the resulting diaphragm in the measurement direction (+), and calculating the ratio (measurement direction (-) / measurement direction (+)). The results are summarized in Table 1 below.

[0049]

[0050] Regarding the results obtained as shown in Table 1, the relationship between the filling angle (°) and the secondary molding height is shown in FIG. 9, and the relationship between the filling angle and the height ratio is shown in FIG.

[0051] The results shown in Table 1 and Figures 9 and 10 indicate that when a metal disc with a flange having a notch in a ±135° direction relative to the rolling direction (reference line) punched from a rolled metal plate is bent in the primary process, the metal diaphragm obtained after the secondary process can be drawn with high precision depending on the bending direction. As shown in Table 1 and Figure 9, it was found that by adjusting the angle difference between the reference line indicating the rolling direction of the metal disc and the folding center line during primary forming so that the fill angle is in the range of 0±6°, the variation in the secondary formed height can be reduced. It was also found that by setting the fill angle in the range of 0±3°, the variation in the secondary formed height can be minimized.

[0052] As shown in Table 1 and Figure 10, by adjusting the angle difference between the reference line indicating the rolling direction of the metal disk and the center line of the bending during primary forming so that the fill angle is within the range of 0±6°, it was found that the variation in the height ratio of the metal diaphragm can be reduced to within 15%. Furthermore, by adjusting the aforementioned angle difference so that the fill angle is within the range of 0±3°, it was found that the variation in the height ratio of the metal diaphragm can be reduced to within 8%. Furthermore, when a metal diaphragm with a flange manufactured with a fill angle within the range of 0±6° was placed on a flat surface such as a desk with the flange facing down, no rattle occurred in the metal diaphragm even when pressed with a finger. In contrast, when a diaphragm manufactured with a fill angle within the range of 0±10°, 0±20°, or 0±30° was placed on a flat surface such as a desk with the flange facing down, a clear rattle occurred when the metal diaphragm was pressed with a finger.

[0053] 1...rolled metal plate, 2...contour line, 3...punched material, 3a...cutout portion (identification portion), 5...metal diaphragm, 7...holder, 8...recess, 9...receiving member, 10...rubber plate, 11...punch, 15...diaphragm, 15a...dome portion, 15b...flange portion, 15c...cutout portion, d...reference line, H...height, D...diameter, LD...rolling direction, TD...direction perpendicular to rolling.

Claims

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

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

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

5. The metal 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. A punching material is formed by punching a rolled metal sheet having rolling anisotropy. After performing primary processing in which the punching material is bent symmetrically with a straight line parallel to the rolling direction as the center line, when performing secondary processing to form a metal diaphragm having a partial spherical shell shape by drawing, After forming the punching material by punching the rolled metal sheet so as to have an identification part in at least one of a first direction that is 45° ± 6° in the circumferential direction in plan view of the partial spherical shell shape, a second direction that is 135° ± 6° in the circumferential direction in plan view of the partial spherical shell shape, a third direction that is -45° ± 6° in the circumferential direction in plan view of the partial spherical shell shape, and a fourth direction that is -135° ± 6° in the circumferential direction in plan view of the partial spherical shell shape, The primary processing is performed on the punching material using a straight line parallel to the rolling direction recognized with the identification part as a bending center line. A method for manufacturing a metal diaphragm, characterized by this.

7. The method for manufacturing a metal diaphragm according to claim 6, characterized in that the first direction is 45° ± 3° in the circumferential direction in plan view, the second direction is 135° ± 3° in the circumferential direction in plan view, the third direction is -45° ± 3° in the circumferential direction in plan view, and the fourth direction is -135° ± 3° in the circumferential direction in plan view.

8. The method for manufacturing a metal diaphragm according to claim 6 or claim 7, characterized in that an identification part is formed in the first direction and the second direction, or an identification part is formed in the third direction and the fourth direction.

9. The method for manufacturing a metal diaphragm according to claim 6 or claim 7, characterized in that a notch or an orientation flat is formed as the identification part.

10. The method for manufacturing a metal diaphragm according to claim 6 or claim 7, 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.

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