Valve body and method for molding a valve body

Abstract

To provide a valve body which can use a flat plate-shaped valve disc, can make fluid smoothly flow, and can be easily manufactured.SOLUTION: In a valve body for accommodating a butterfly valve body in a cylindrical body so as to be turnable, having an integrated valve seat face protruding toward the inside of the cylindrical body in a radial direction, and constituting a butterfly valve, the valve seat face is formed of a cylindrical peripheral face which is formed so as to protrude toward the inside of the cylindrical body in the radial direction, and formed into a plane shape having an arc shape not an annular shape. A rectification face being a face for connecting a ridge line being an end part of the valve seat face at the inside of the cylindrical body in the radial direction, and an internal peripheral face of the cylindrical body is formed at a rear flow side of the valve seat face in a valve-closing direction being a turning direction of the butterfly valve body at valve-closing, and an adjustment face being a face for connecting both ends of the valve seat face of the cylindrical body in a peripheral direction, both ends of the rectification face of the cylindrical body in the peripheral direction, and an internal peripheral face of the cylindrical body to one another is formed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a valve body and a method for molding a valve body. [Background Art]

[0002] For example, in a valve body that houses a butterfly valve for controlling the flow rate of fluid by connecting it to an exhaust pipe of an internal combustion engine and / or a pipe for construction equipment, etc., weight reduction and / or improved reliability are demanded. Accordingly, in this technical field, there is known a technique of integrally forming a valve seat surface (seating surface) on which a valve element is seated with the valve body on a peripheral wall of a cylindrical metal valve body.

[0003] For example, Patent Document 1 (Japanese Utility Model Laid-Open No. 6-80840) discloses that an annular bead portion 4a protruding inward over the entire circumference is integrally formed on a cylindrical valve body (exhaust pipe 4 serving as the valve body) by plastic working, and the butterfly valve is closed by bringing a butterfly valve element 3 bent into a Z-shape into contact with a side surface of the bead portion 4a. In this configuration, the side surface of the bead portion 4a over the entire circumference serves as the valve seat surface. As a result, the mount portion of the rotating shaft 2 including the seating surface for attaching the rotating shaft 2 to the exhaust pipe 4 (flat portions 4d and 4e for fixing bearing cases 6 and 7 serving as the seating surface) interferes with the bead portion 4a. As a result, the valve shaft (the rotating shaft 2 serving as the valve shaft) of the butterfly valve element 3 is also shortened, and the configuration of the mount portion of the rotating shaft 2 is also restricted.

[0004] Furthermore, for a butterfly valve, it is desirable in terms of strength and fluid dynamics that the butterfly valve element 3 has a flat plate shape. However, since the bead portion 4a has a certain width (dimension in the axial direction of the exhaust pipe 4), it is necessary to offset the first valve element 3a and the second valve element 3b respectively present on both sides of the rotating shaft 2 of the butterfly valve element 3 by the width. For this reason, the cross-section of the butterfly valve element 3 taken along a plane orthogonal to the rotating shaft 2 has a Z-shaped shape.

[0005] On the other hand, Patent Document 2 (Japanese Patent No. 4578923) discloses a structure in which the pipe is closed by the fact that one peripheral edge of the valve body relative to the pivot axis abuts against a first stage provided on the inner surface of the pipe, and the other peripheral edge of the valve body relative to the pivot axis abuts against a second stage provided on the inner surface of the pipe. In this structure, the first and second stages are not continuous in an annular shape over the entire circumference as in Patent Document 1 mentioned above, but are formed only on opposite sides of the pivot axis, so it is said that the reduction in the flow path cross-sectional area can be suppressed compared to the butterfly valve disclosed in Patent Document 1 mentioned above.

[0006] However, the process of forming steps on the inner surface of a pipe by cutting is more time-consuming and involves greater material loss compared to the process of forming steps by plastic deformation, as described in Patent Document 1 above, and raises concerns about increased manufacturing costs.

[0007] In other words, in this technical field, there is a need for a valve body that can use a flat valve element, can achieve smooth fluid flow, and can be easily manufactured. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Utility Model Publication No. 6-80840 [Patent Document 2] Patent No. 4578923 [Patent Document 3] Patent No. 6353791 [Overview of the project] [Problems that the invention aims to solve]

[0009] As mentioned above, in this technical field, there is a need for a valve body that can use a flat plate-shaped valve element, can achieve smooth fluid flow, and can be easily manufactured. [Means for solving the problem]

[0010] In view of the above problems, the inventors have conducted diligent research and have found that the above problems can be solved by forming an arc-shaped valve seat surface integrally in the valve body of a butterfly valve by making the circumferential wall protrude inward, forming a smooth flow straightening surface on the downstream side of the valve seat surface in the rotational direction when the valve body is closed, and providing an adjustment surface which is a region surrounded by both ends of the valve seat surface in the circumferential direction of the cylindrical body, both ends of the flow straightening surface in the circumferential direction of the cylindrical body, and the inner circumferential surface of the valve body.

[0011] Specifically, the valve body according to the present invention (hereinafter sometimes referred to as "the valve body of the present invention") is a valve body that constitutes a butterfly valve by rotatably housing a butterfly valve body inside a cylindrical body and integrally forming a valve seat surface that protrudes inward in the radial direction of the cylindrical body. The valve seat surface is formed by the peripheral wall of the cylindrical body which is shaped to protrude inward in the radial direction of the cylindrical body, and is a flat surface having an arc shape rather than an annular shape.

[0012] Furthermore, in the valve body of the present invention, a flow-straightening surface, which is a surface connecting the ridge line that is the end of the inner valve seat surface in the radial direction of the cylindrical body and the inner circumferential surface of the cylindrical body, is formed on the downstream side of the valve seat surface in the closing direction, which is the rotation direction when the butterfly valve body is closed. In addition, an adjustment surface is formed, which is a surface connecting both ends of the valve seat surface in the circumferential direction of the cylindrical body, both ends of the flow-straightening surface in the circumferential direction of the cylindrical body, and the inner circumferential surface of the cylindrical body.

[0013] On the other hand, the method for forming a valve body according to the present invention (hereinafter sometimes referred to as "the present invention forming method") is the above-described method for forming a valve body according to the present invention, and includes the following first to third steps.

[0014] The first step is to insert a first core, which has a first molded surface that corresponds to the valve seat surface, from one end of the cylindrical body. The second step is to insert a second core, which has a second molding surface corresponding to the rectifying surface and a third molding surface corresponding to the adjustment surface, from the other end of the cylindrical body. The third step is to press a crushing die, which has a fourth molding surface corresponding to the valve seat surface, the rectifying surface, and the adjustment surface, from the outside to the inside of the cylindrical body, while the first surface, which is the tip surface of the first core, and the second surface, which is the tip surface of the second core, are in contact with and fitted together inside the cylindrical body, so as to sandwich the peripheral wall of the cylindrical body between the first molding surface, the second molding surface, the third molding surface and the fourth molding surface.

[0015] Furthermore, in the molding method of the present invention, the first and second surfaces are configured such that, after the completion of the third step, the first core can be removed from one end of the cylindrical body and the second core can be removed from the other end of the cylindrical body. [Effects of the Invention]

[0016] In the valve body according to the present invention, as described above, the valve seat surface is integrally formed by the circumferential wall of a cylindrical body which is molded to protrude inward in the radial direction of the cylindrical body. Such a valve seat surface can be formed by plastic deformation, as described in the molding method of the present invention. Therefore, compared to the case in which a step is formed on the inner circumferential surface of the pipe by cutting, as in the structure disclosed in Patent Document 2, the processing time is shorter, material loss is smaller, and manufacturing costs can be reduced.

[0017] Furthermore, the valve seat surface of the valve body according to the present invention is a flat surface with an arc shape rather than an annular shape. Therefore, the mounting portion for attaching the pivot shaft to the valve body does not interfere with the valve seat surface, and there is no need to shorten the pivot shaft of the butterfly valve body or to be restricted in the configuration of the mounting portion for attaching the pivot shaft to the valve body, as was the case with the butterfly valve disclosed in Patent Document 1 mentioned above.

[0018] Furthermore, unlike the butterfly valve disclosed in the aforementioned Patent Document 1, the valve seat is not constituted by the side surface of a bead portion that is formed over the entire circumference of the valve body and has a predetermined width. Therefore, it is not necessary for the butterfly valve body to be seated on a valve seat surface that is necessarily offset by a predetermined distance in the axial direction of the valve body, and thus it is not necessary to use a butterfly valve element having a Z-shaped cross-sectional shape. That is, in the valve body of the present invention, a flat plate-shaped butterfly valve element that is desirable in terms of strength and hydrodynamics can be used.

[0019] In addition, in the valve body of the present invention, a flow rectifying surface, which is a surface connecting a ridge line that is an end portion of an inner valve seat surface in the radial direction of the cylindrical body and the inner circumferential surface of the cylindrical body, is formed on the wake side of the valve seat surface in the valve closing direction, and an adjustment surface surrounded by both ends of the valve seat surface in the circumferential direction of the cylindrical body, both ends of the flow rectifying surface in the circumferential direction of the cylindrical body, and the inner circumferential surface of the cylindrical body is formed. That is, unlike the butterfly valve disclosed in the aforementioned Patent Document 1 and the structure disclosed in the aforementioned Patent Document 2, there is no steep step around the valve seat surface. Therefore, problems such as an increase in back pressure and / or generation of abnormal noise caused by the generation of turbulent flow around the valve seat surface can be reduced.

[0020] That is, according to the present invention, it is possible to provide a valve body that can use a flat plate-shaped valve element, achieve smooth fluid flow, and can be easily manufactured.

[0021] Other objects, other features and attendant advantages of the present invention will be readily understood from the description of each embodiment of the present invention described below with reference to the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [Figure 1] It is a schematic perspective view showing an example of the configuration of a valve body (first valve body) according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram showing an example of the configuration of a valve body (second valve body) according to a second embodiment of the present invention. [Figure 3] It is a schematic diagram illustrating an example configuration of a second valve body according to another aspect. [Figure 4] It is a schematic diagram illustrating an example configuration of a valve body (third valve body) according to a third embodiment of the present invention. [Figure 5] It is a schematic diagram illustrating an example configuration of a valve body (fourth valve body) according to a fourth embodiment of the present invention. [Figure 6] It is a schematic diagram illustrating an example configuration of a fourth valve body according to another aspect. [Figure 7] It is a flowchart exemplifying the flow of each step included in a valve body molding method (fifth molding method) according to a fifth embodiment of the present invention. [Figure 8] It is a schematic cross-sectional view exemplifying the shape and positional relationship of each member upon completion of the first to third steps included in the fifth molding method. [Figure 9] It is a schematic diagram illustrating an example configuration of a first core and a second core used in a valve body molding method (sixth molding method) according to a sixth embodiment of the present invention. [Figure 10] It is a schematic cross-sectional view exemplifying the shape and positional relationship of each member upon completion of the first to third steps included in a valve body molding method (seventh molding method) according to a seventh embodiment of the present invention. [Figure 11] It is a schematic diagram illustrating an example of a step performed after the third step included in the seventh molding method is completed. [Figure 12] It is a schematic diagram illustrating an example configuration of a third core and a fourth core used in a valve body molding method (eighth molding method) according to an eighth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] First Embodiment Hereinafter, a valve body (hereinafter may be referred to as "first valve body") according to the first embodiment of the present invention will be described with reference to the drawings.

[0024] <composition> Figure 1 is a schematic perspective view showing an example of the configuration of a first valve body. The first valve body 101 illustrated in Figure 1 is a valve body that constitutes a butterfly valve, with a rotatable house of a butterfly valve body (not shown) inside a cylindrical body 10 and an integrally formed valve seat surface 11 projecting inward in the radial direction of the cylindrical body 10. Although the valve seat surface 11 is formed inside the cylindrical body 10, it is difficult to illustrate the inside of the cylindrical body 10, so in Figure 1, the part of the outer surface of the cylindrical body 10 corresponding to the valve seat surface 11 is indicated by a reference numeral. The same applies to the ridges and ends of the valve seat surface 11, the straightening surface and both ends of the straightening surface, and the adjustment surface, which will be described later.

[0025] The cylindrical body 10 constituting the first valve body 101 is not particularly limited as long as it has a material and shape that can withstand the operating environment, such as the stress acting on the first valve body 101 when used as a butterfly valve, and the pressure and temperature of the fluid flowing inside the first valve body 101. Typically, the cylindrical body 10 constituting the first valve body 101 is a cylindrical member formed of a metal such as iron, copper, and aluminum, or an alloy containing these metals, such as stainless steel.

[0026] The valve seat surface 11 is formed by the circumferential wall of the cylindrical body 10, which is molded to protrude inward in the radial direction of the cylindrical body 10. Specifically, such a valve seat surface 11 can be formed by plastic deformation of the cylindrical body 10, as will be described later. Therefore, compared to the case where a step is formed on the inner circumferential surface of the pipe by cutting, as in the structure disclosed in the aforementioned Patent Document 2, for example, the processing time is shorter, material loss is smaller, and manufacturing costs can be reduced.

[0027] Furthermore, the valve seat surface 11 is a flat surface with an arc shape rather than an annular shape, as illustrated in Figure 1. That is, the valve seat surface 11 is not formed around the entire circumference of the cylindrical body 10. Therefore, the valve seat surface 11 does not interfere with a mounting portion (not shown) for attaching a pivot shaft (not shown) to the first valve body 101, so there is no need to shorten the pivot shaft or to be constrained by the configuration of the mounting portion for attaching the pivot shaft to the first valve body 101.

[0028] In addition, in the first valve body 101, the valve seat is not formed by the side surface of a bead portion that is formed over the entire circumference of the valve body and has a predetermined width, as in the butterfly valve disclosed in the aforementioned Patent Document 1. Therefore, even when two valve seat surfaces 11 are provided on both sides of the pivot axis, these valve seat surfaces 11 can be formed such that the plane containing both valve seat surfaces 11 lies in the same plane, so it is not necessarily required to use a butterfly valve body having a Z-shaped cross-section. In other words, in the valve body of the present invention, a flat butterfly valve body that is desirable in terms of strength and hydrodynamics can be used.

[0029] Furthermore, in the first valve body 101, a flow-straightening surface 12, which is the surface connecting the ridge line 11R, which is the end of the inner valve seat surface 11 in the radial direction of the cylindrical body 10, and the inner circumferential surface of the cylindrical body 10, is formed on the downstream side (forward side in Figure 1) of the valve seat surface 11 in the closing direction, which is the rotational direction when the butterfly valve body is closed.

[0030] In addition, an adjustment surface 13 is formed, which connects both ends 11E of the valve seat surface 11 in the circumferential direction of the cylindrical body 10, both ends 12E of the rectifying surface 12 in the circumferential direction of the cylindrical body 10, and the inner circumferential surface of the cylindrical body 10. In other words, the adjustment surface 13 is the region enclosed by both ends 11E of the valve seat surface 11, both ends 12E of the rectifying surface 12, and the inner circumferential surface of the cylindrical body 10, and in the example shown in Figure 1, it has a roughly triangular shape.

[0031] In the first valve body 101 illustrated in Figure 1, a shaft hole 14 for inserting a pivot shaft of a butterfly valve body (not shown) is drilled in the peripheral wall of the cylindrical body 10. However, the configuration of the mounting part for attaching the pivot shaft and / or a drive mechanism for rotating the pivot shaft to the first valve body 101 is not limited to the example shown in Figure 1. As will be described later, a flat seating surface may be formed on the peripheral edge of the shaft hole 14 by, for example, press working, or the peripheral edge of the shaft hole 14 may be raised by, for example, burring.

[0032] In the first valve body 101, as described above, a rectifying surface 12 and an adjustment surface 13 are formed around the valve seat surface 11. Therefore, unlike the butterfly valve disclosed in Patent Document 1 and the structure disclosed in Patent Document 2, there are no steep steps around the valve seat surface 11. Accordingly, problems such as an increase in back pressure and / or the generation of abnormal noise caused by turbulence around the valve seat surface 11 can be reduced.

[0033] Furthermore, from the viewpoint of reducing the generation of turbulence in the fluid flow that flows over the ridge line 11R of the valve seat surface 11, it is preferable that the ridge line 11R of the valve seat surface 11 and the inner circumferential surface of the cylindrical body 10 are smoothly connected by the flow straightening surface 12. More preferably, in a cross-section of a plane including the axis of the cylindrical body 10, there are no inflection points on the flow straightening surface 12. Similarly, from the viewpoint of reducing the generation of turbulence in the fluid flow that flows over both ends 11E of the valve seat surface 11, it is preferable that both ends 11E of the valve seat surface 11, both ends 12E of the flow straightening surface 12, and the inner circumferential surface of the cylindrical body 10 are smoothly connected by the adjustment surface 13. More preferably, in a cross-section of a plane including the axis of the cylindrical body 10, there are no inflection points on the adjustment surface 13.

[0034] <effect> As described above, according to the first embodiment of the present invention, it is possible to use a flat plate-shaped valve body, achieve smooth fluid flow, and provide a valve body that can be easily manufactured.

[0035] 《Second Embodiment》 The valve body according to the second embodiment of the present invention (hereinafter sometimes referred to as the "second valve body") will be described below with reference to the drawings.

[0036] In the butterfly valve disclosed in Patent Document 1 and the structure disclosed in Patent Document 2, the valve seat surface is formed as a plane perpendicular to the axial direction of the valve body. Similarly, in the valve body according to the present invention (Valve Body of the Present Invention), the valve seat surface 11 may be formed as a plane perpendicular to the axial direction of the cylindrical body 10 constituting the valve body.

[0037] Incidentally, in order to improve the sealing performance when the valve is closed, it is necessary to make the valve seat surface 11 protrude significantly toward the inside of the cylindrical body 10 to increase the overlap between the butterfly valve body and the valve seat surface 11. Furthermore, in order to avoid contact between the butterfly valve body and the inner surface of the cylindrical body 10 when thermal expansion of the butterfly valve body and / or the cylindrical body 10 occurs at high temperatures, it is necessary to ensure a certain amount of clearance between the butterfly valve body, which is seated (contacting) the valve seat surface when the valve is closed, and the inner surface of the cylindrical body 10. From this viewpoint as well, it is necessary to make the valve seat surface 11 protrude significantly toward the inside of the cylindrical body 10.

[0038] However, if the valve seat surface 11 protrudes significantly inward from the cylindrical body 10 as described above, the cross-sectional area of ​​the flow path in that portion decreases, and the step difference between the inner circumferential surface of the cylindrical body 10 adjacent to the valve seat surface 11 and the ridge line 11R of the valve seat surface 11 increases. As a result, the fluid flow in that portion becomes turbulent, raising concerns about problems such as an increase in back pressure and / or the generation of abnormal noise.

[0039] In the field of this technology, it is known that a valve seat surface is provided so as to be inclined with respect to the axial direction of a cylindrical valve body as a means of solving the above-mentioned problems. For example, when forming a valve seat surface by plastic deformation, as disclosed in Patent Document 3 (Japanese Patent No. 6353791), a valve seat surface inclined with respect to the axial direction of the valve body can be formed by bending the peripheral edge of the end of the cylindrical valve body by press working. However, a technique for forming a valve seat surface inclined with respect to the axial direction of the valve body by plastic deformation in the middle of the cylindrical valve body, rather than at the end, is not yet known.

[0040] Furthermore, as mentioned above, even when forming a valve seat surface perpendicular to the axial direction of the valve body, the process of forming the valve seat surface by cutting is more expensive than the process of forming the valve seat surface by plastic deformation, for example, because the processing time is longer, the material loss is greater, and there are concerns about increased manufacturing costs. Moreover, when forming a valve seat surface inclined with respect to the axial direction of the valve body, there are even greater concerns about increased manufacturing costs due to factors such as increased complexity of processing control, further lengthening of processing time, and further increase in material loss.

[0041] <composition> Therefore, the second valve body is the first valve body described above, characterized in that it satisfies the following requirements in a cross-section of a plane including the axis of the cylindrical body. The valve seat angle, which is the angle formed between the valve seat surface and the inner circumferential surface of the cylindrical body adjacent to the valve seat surface on the inner side in the radial direction of the cylindrical body, is 90 degrees or greater. The flow straightening angle, which is the angle formed between the flow straightening surface and the inner circumferential surface of the cylindrical body adjacent to the flow straightening surface on the inner side in the radial direction of the cylindrical body, is greater than the valve seat angle described above.

[0042] Figure 2 is a schematic diagram showing an example of the configuration of the second valve body. Figure 2(a) is a schematic front view of the second valve body 102 when viewed from one end, (b) is a schematic side view of the cross-section of the second valve body 102 when viewed from the side, with respect to the straight line AA shown in (a) and the axis AX of the cylindrical body 10, and (c) is a schematic side view of the cross-section of the second valve body 102 when viewed from the side, with respect to the straight line BB shown in (a) and the axis AX of the cylindrical body 10.

[0043] In the second valve body 102, as illustrated in Figure 2(b), the valve seat angle θs, which is the angle between the valve seat surface 11 and the inner circumferential surface of the cylindrical body adjacent to the valve seat surface 11 in a cross-section of the cylindrical body 10 with respect to the axis AX of the cylindrical body 10, is obtuse (greater than 90 degrees). As a result, even if the area of ​​the valve seat surface 11 is increased for purposes such as improving sealing performance when the valve is closed and / or ensuring clearance between the butterfly valve body and the inner circumferential surface of the cylindrical body 10 at high temperatures, the amount of protrusion of the valve seat surface 11 toward the inside in the radial direction of the cylindrical body 10 can be reduced compared to the case where the valve seat angle θs is 90 degrees. As a result, problems such as an increase in back pressure and / or the generation of abnormal noise caused by turbulence in the fluid flow through that part can be reduced.

[0044] Furthermore, the flow straightening angle θa, which is the angle formed between the flow straightening surface 12 and the inner circumferential surface of the cylindrical body 10 adjacent to the flow straightening surface 12 on the inside of the cylindrical body 10 in the radial direction, is greater than the valve seat angle θs (θa > θs). That is, the portion adjacent to the valve seat surface 11, straddling the ridge line 11R of the valve seat surface 11, is formed as a gentle slope. Therefore, compared to the case where this portion is formed as a steep step, problems such as an increase in back pressure and / or the generation of abnormal noise caused by turbulence in the fluid flowing over the ridge line 11R of the valve seat surface 11 when the valve is opened can be reduced.

[0045] As mentioned above, the configuration of the mounting portion for attaching the pivot shaft and / or the drive mechanism for rotating the pivot shaft to the cylindrical body 10 is not limited to the example shown in Figure 1, which was referenced in the description of the first valve body 101. As illustrated in Figure 2(c), a flat seating surface 14S may be formed on the periphery of the shaft hole 14 by, for example, press working, or the periphery of the shaft hole 14 may be raised by, for example, burring. In addition, in the examples shown in Figures 2(b) and (c), an enlarged diameter portion is formed at one end of the cylindrical body 10 (the right end in the drawing), which has a larger diameter than the other parts. Such an enlarged diameter portion is provided for the purpose of connecting to other adjacent members, such as the exhaust pipe of an internal combustion engine and / or piping for building equipment. However, such an enlarged diameter portion is not an essential component of the valve body according to the present invention.

[0046] Incidentally, as mentioned above, in the second valve body, the valve seat angle, which is the angle formed between the valve seat surface and the inner circumferential surface of the cylindrical body adjacent to the valve seat surface on the inside in the radial direction of the cylindrical body, is 90 degrees or more. That is, the second valve body does not exclude the possibility of a 90-degree angle. Figure 3 is a schematic diagram showing an example of the configuration of the second valve body according to another embodiment. More specifically, Figure 3 is a schematic side view, similar to Figure 2(b), of the cross-section of the second valve body 102' when observed from the side, with a plane that includes the axis AX of the cylindrical body 10 and passes through the center of the rectifying surface 12 in the circumferential direction of the cylindrical body 10.

[0047] As illustrated in Figure 3, in the second valve body 102', the valve seat angle θs, which is the angle formed between the valve seat surface 11 and the inner circumferential surface of the cylindrical body adjacent to the valve seat surface 11 on the radial side of the cylindrical body 10 in a cross-section of the cylindrical body 10 with respect to the axis AX, is a right angle (equal to 90 degrees). If increasing the protrusion amount of the valve seat surface 11 does not result in problems such as an increase in back pressure and / or the generation of abnormal noise caused by turbulence in the fluid flow through that part, then the valve seat angle θs may be 90 degrees in this manner.

[0048] Furthermore, in the second valve body 102' illustrated in Figure 3, similar to the second valve body 102 illustrated in Figure 2(b), the rectification angle θa is greater than the valve seat angle θs (θa > θs). That is, the portion adjacent to the valve seat surface 11, straddling the ridge line 11R of the valve seat surface 11, is formed as a gentle slope. Therefore, compared to the case where this portion is formed as a steep step, problems such as an increase in back pressure and / or the generation of abnormal noise caused by turbulence in the fluid flowing over the ridge line 11R of the valve seat surface 11 when the valve is opened can be reduced.

[0049] <effect> As described above, in the second embodiment of the present invention, the valve seat angle is 90 degrees or more, and the flow straightening angle is greater than the valve seat angle. As a result, according to the second embodiment of the present invention, in addition to the effects achieved by the first embodiment described above, it is possible to more reliably reduce problems such as an increase in back pressure and / or the generation of abnormal noise caused by the generation of turbulence in the fluid that flows over the valve seat surface and the flow straightening surface when the valve is opened, thereby further enhancing the effect of achieving a smooth fluid flow.

[0050] 《Third Embodiment》 The valve body according to the third embodiment of the present invention (hereinafter sometimes referred to as the "third valve body") will be described below with reference to the drawings.

[0051] When a butterfly valve is closed, the contact surface of the butterfly valve body with the valve seat surface (hereinafter sometimes referred to as the "contact surface") comes into contact with the valve seat surface, stopping the rotation of the butterfly valve body and minimizing the flow rate of fluid inside the cylindrical body. Since the fluid flow rate when the valve is closed is affected by the gap between the outer edge of the butterfly valve body and the inner surface of the cylindrical body when the valve is closed, it is necessary to provide a valve seat surface such that the rotation of the butterfly valve body stops at an angle that results in a desired fluid flow rate when the valve is closed.

[0052] To achieve the above objective, it is sufficient to have one valve seat surface formed on the inner circumferential surface of one of the cylindrical bodies on either side of the pivot axis of the butterfly valve body. However, from the viewpoint of improving sealing performance when the valve is closed, it is preferable to have valve seat surfaces formed on the inner circumferential surfaces of the cylindrical bodies on both sides of the pivot axis of the butterfly valve body.

[0053] <composition> Therefore, the third valve body is the first valve body or the second valve body described above, characterized in that the valve seat surface, the rectifying surface, and the adjustment surface are formed on the inner circumferential surfaces of cylindrical bodies on both sides of the pivot axis of the butterfly valve body, as the first valve seat surface, the first rectifying surface, and the first adjustment surface, and as the second valve seat surface, the second rectifying surface, and the second adjustment surface, respectively.

[0054] As illustrated in Figures 2 and 3, the second valve body 102 and the second valve body 102' described above have a valve seat surface 11, a flow straightening surface 12, and an adjustment surface 13 formed on the inner circumferential surfaces of the cylindrical bodies 10 on both sides of the pivot axis of a butterfly valve body (not shown). In other words, the second valve body 102 and the second valve body 102' described above are valve bodies that also satisfy the requirements of a third valve body.

[0055] Furthermore, in the second valve body 102 and the second valve body 102', the valve seat angles θs of the two valve seat surfaces 11 are equal, and the planes containing the two valve seat surfaces 11 are parallel to each other. However, the two valve seat surfaces 11 (and the planes containing them) do not necessarily have to be parallel to each other, and the valve seat angles θs of the two valve seat surfaces 11 may be different.

[0056] Figure 4 is a schematic diagram showing an example of the configuration of a third valve body in which the valve seat angles θs of the two valve seat surfaces 11 are different from each other. More specifically, Figure 4 is a schematic side view of the cross-section of the third valve body 103 observed from the side, with a plane that includes the axis AX of the cylindrical body 10 and passes through the center of the rectifying surface 12 in the circumferential direction of the cylindrical body 10, similar to Figures 2(b) and 3. As illustrated in Figure 4, in the third valve body 103, the valve seat surface 11, the rectifying surface 12, and the adjustment surface 13 are formed on the inner circumferential surfaces of the cylindrical body 10 on both sides of the pivot axis 21 of the butterfly valve body 20, respectively.

[0057] Furthermore, the plate-shaped member (disk) that constitutes the butterfly valve body 20 housed inside the third valve body 103 is bent near the pivot axis 21, as illustrated in Figure 4, and one side of the disc on the pivot axis 21 is inclined relative to the other side. In accordance with such a butterfly valve body 20, if the upper valve seat surface 11 in the third valve body 103 is designated as the first valve seat surface and the lower valve seat surface 11 in the third valve body 103 is designated as the second valve seat surface, then the valve seat angles of the first valve seat surface and the valve seat angles of the second valve seat surface are different. That is, these two valve seat surfaces (and the planes including them) are not parallel to each other. The third valve body does not exclude such a configuration.

[0058] <effect> As described above, in the third embodiment of the present invention, a set of a valve seat surface, a flow straightening surface, and an adjustment surface is formed on the inner circumferential surfaces of the cylindrical bodies on both sides of the pivot axis of the butterfly valve body. As a result, according to the third embodiment of the present invention, in addition to the effects achieved by the first or second embodiment described above, the sealing performance when the valve is closed can be improved.

[0059] 《Fourth Embodiment》 Hereinafter, a valve body according to the fourth embodiment of the present invention (hereinafter sometimes referred to as the "fourth valve body") will be described with reference to the drawings.

[0060] In the third valve body 103 illustrated in Figure 4, the plate-shaped member (disk) constituting the butterfly valve body 20 is bent near the pivot axis 21, and one side of the disk on the pivot axis 21 is inclined relative to the other side. When one side of the disk on the pivot axis 21 is inclined relative to the other side in this way, the larger the inclination angle, the larger the projected area of ​​the butterfly valve body 20 in the perpendicular projection of the fluid flow direction inside the third valve body 103 (i.e., inside the cylindrical body 10). As a result, the flow path cross-sectional area in that part becomes smaller, raising concerns about problems such as an increase in back pressure.

[0061] In order to ensure the maximum fluid flow rate in a butterfly valve, it is preferable that the projected area of ​​the butterfly valve body when fully open be as small as possible in a perpendicular projection view in the direction of fluid flow. From this viewpoint, it is preferable that the first contact surface, which is the surface that abuts the first valve seat surface of the butterfly valve body, and the second contact surface, which is the surface that abuts the second valve seat surface, are parallel to each other. In this case, naturally, the first and second valve seat surfaces formed on the valve body are configured to fit a butterfly valve body having such a configuration.

[0062] <composition> In other words, the fourth valve body is the third valve body described above, characterized in that it satisfies requirements A to C listed below. Requirement A is that the first valve seat plane, which includes the first valve seat surface, and the second valve seat plane, which includes the second valve seat surface, are parallel to each other and separated by a predetermined distance, which is a first distance. Requirement B is that the first contact plane, which includes the first contact surface that the butterfly valve body sits on the first valve seat surface when closed, and the second contact plane, which includes the second contact surface that the butterfly valve body sits on the second valve seat surface when closed, are parallel to each other and separated by a predetermined distance, which is a second distance. Requirement C is that the first distance is equal to the second distance.

[0063] Figure 5 is a schematic diagram showing an example of the configuration of the fourth valve body. More specifically, Figure 5 is a schematic side view of the cross-section of the fourth valve body 104, observed from the side, with the axis AX of the cylindrical body 10 included and a plane passing through the center of the rectifying surface 12 in the circumferential direction of the cylindrical body 10. However, in Figure 5, the axis AX of the cylindrical body 10 is omitted due to space limitations. The butterfly valve body 20 in the closed position is depicted with a solid line, and the butterfly valve body 20 in the fully open position is depicted with a dashed line.

[0064] As illustrated in Figure 5, in the fourth valve body 104, the first valve seat plane PS1, which includes the first valve seat surface 11a, and the second valve seat plane PS2, which includes the second valve seat surface 11b, are parallel to each other and separated by a predetermined distance, the first distance D1. Furthermore, the first contact plane PC1, which includes the first contact surface 22a, which is the plane that seats on the first valve seat surface 11a when the butterfly valve body 20 is closed, and the second contact plane PC2, which includes the second contact surface 22b, which is the plane that seats on the second valve seat surface 11b when the butterfly valve body 20 is closed, are parallel to each other and separated by a predetermined distance, the second distance D2. Moreover, the first distance D1 is equal to the second distance D2 (D1 = D2).

[0065] In other words, the first distance D1, which is the distance between the first valve seat plane PS1 and the second valve seat plane PS2 in the fourth valve body 104, is set to match the second distance D2, which is the distance between the first contact plane PC1 and the second contact plane PC2 in the butterfly valve body 20. As illustrated in Figure 5, the butterfly valve body 20 housed in the fourth valve body 104 has a Z-shaped cross-section defined by a plane perpendicular to the pivot axis 21. In this case, the second distance D2 is the sum of the thickness of the portion of the plate-shaped member (disk) constituting the butterfly valve body 20 that includes the first contact surface 22a, the thickness of the portion that includes the second contact surface 22b, and the size of the bent portion that fixes the disk to the pivot axis 21 in a direction perpendicular to the first contact surface 22a and the second contact surface 22b. Furthermore, the first distance D1 is set to match the second distance D2 determined in this way.

[0066] Incidentally, as stated at the beginning of this specification, it is desirable for the butterfly valve body to be flat for strength and hydrodynamic reasons. Figure 6 is a schematic diagram showing an example of the configuration of a fourth valve body according to another embodiment. More specifically, Figure 6 is a schematic side view of the cross-section of the fourth valve body 104' observed from the side, including the axis AX of the cylindrical body 10 and passing through the center of the rectifying surface 12 in the circumferential direction of the cylindrical body 10, similar to Figure 2(b) and Figures 3 to 5. However, in Figure 6 as in Figure 5, the axis AX of the cylindrical body 10 is omitted due to space limitations. Also, the butterfly valve body 20 in the closed position is depicted with a solid line, and the butterfly valve body 20 in the fully open position is depicted with a dashed line.

[0067] As illustrated in Figure 6, the fourth valve body 104' satisfies the requirements that the fourth valve body 104 must satisfy, and houses a flat butterfly valve body 20. In this case, the thickness of the plate-shaped member (disk) constituting the butterfly valve body 20 becomes the second distance D2, and the first distance D1 is set to match the second distance D2 determined in this way.

[0068] As a result of the above, when the valve is closed, as shown by the solid lines in Figures 5 and 6, the first contact surface 22a of the butterfly valve body 20 can seat on the first valve seat surface 11a, and at the same time, the second contact surface 22b of the butterfly valve body 20 can seat on the second valve seat surface 11b. On the other hand, when fully open, as shown by the dashed lines in Figures 5 and 6, the projected area of ​​the butterfly valve body 20 in the perpendicular projection view of the fluid flow direction inside the cylindrical body 10 can be made as small as possible, thereby ensuring as large a flow path cross-sectional area as possible in that portion.

[0069] However, in reality, the first distance D1 and the second distance D2 may not be exactly the same. For example, if there is a small gap between the first valve seat surface 11a and the first contact surface 22a and a small gap between the second valve seat surface 11b and the second contact surface 22b when the valve is closed, the first distance D1 will be slightly larger than the second distance D2 by an amount corresponding to these gaps (D1 > D2).

[0070] <effect> As described above, in the fourth embodiment of the present invention, the distance between the first and second valve seat planes of the valve body, which are parallel to each other (first distance), and the distance between the first and second contact planes of the butterfly valve body, which are parallel to each other (second distance), are equal. This allows the butterfly valve body to be seated simultaneously on the first and second valve seat planes when the valve is closed. On the other hand, when the valve is fully open, the projected area of ​​the butterfly valve body in the perpendicular projection diagram of the fluid flow direction inside the valve body can be made as small as possible, thereby maximizing the flow path cross-sectional area in that portion. As a result, according to the fourth embodiment of the present invention, in addition to the effects achieved by the first to third embodiments described above, problems such as an increase in back pressure can be reduced.

[0071] 《Fifth Embodiment》 As stated at the beginning of this specification, the present invention relates not only to the valve body described herein, but also to a method for molding the valve body. Hereinafter, a method for molding a valve body according to a fifth embodiment of the present invention (hereinafter sometimes referred to as the "fifth molding method") will be described with reference to the drawings.

[0072] Figure 7 is a flowchart illustrating the flow of each step included in the fifth molding method. Figure 8 is a schematic cross-sectional view illustrating the shape and positional relationship of each component at the completion of the first to third steps included in the fifth molding method. Note that in Figure 8, only the portion of the cylindrical body 10 to the left of axis AX as viewed from the drawing is depicted. Furthermore, in the following description, parts not shown will also be denoted by reference numerals in parentheses for the purpose of facilitating understanding of this embodiment.

[0073] <composition> The fifth molding method is a molding method for a valve body according to the present invention (the valve body of the present invention), including the first valve body described above, and includes the first to third steps described later.

[0074] First, in step S10, as illustrated in Figure 8(a), a first step is performed in which a first core 31 having a first molding surface 31a, which corresponds to the valve seat surface 11, is inserted from one end of the cylindrical body 10 (see the white arrow). Next, in step S20, as illustrated in Figure 8(b), a second step is performed in which a second core 32 having a second molding surface 32b, which corresponds to the rectifying surface 12, and a third molding surface (32c), which corresponds to an adjustment surface (13) (not shown), is inserted from the other end of the cylindrical body 10 (see the hatched arrow).

[0075] In the examples shown in Figures 7 and 8, the first core 31 was inserted from the upper end of the cylindrical body 10 toward Figure 8 in the first step (step S10), and the second core 32 was inserted from the lower end of the cylindrical body 10 toward Figure 8 in the next second step (step S20). However, conversely, the first core 31 may be inserted from the lower end of the cylindrical body 10 toward Figure 8 in the first step (step S10), and the second core 32 may be inserted from the upper end of the cylindrical body 10 toward Figure 8 in the next second step (step S20). Furthermore, the second step (step S20) may be performed before the first step (step S10). Moreover, the first step (step S10) and the second step (step S20) may be performed simultaneously.

[0076] Next, in step S30, as illustrated in Figure 8(c), a third step is performed in which the crushing die 40 presses the cylindrical body 10 from the outside to the inside while the first surface 31t, which is the tip surface of the first core 31, and the second surface 32t, which is the tip surface of the second core 32, are in contact with and fitted together inside the cylindrical body 10 (see the black-filled arrow). The crushing die 40 has a fourth molding surface 40a, which corresponds to the valve seat surface 11, the rectifying surface 12, and the adjustment surface (13) not shown. The first core 31 and the second core 32 and the crushing die 40 are arranged such that the peripheral wall of the cylindrical body 10 is sandwiched between the first molding surface 31a, the second molding surface 32b, and the third molding surface (32c) not shown and the fourth molding surface 40a.

[0077] As described above, in the description of the valve body (first valve body) according to the first embodiment of the present invention, the valve seat surface 11, the rectifying surface 12, and the adjustment surface 13 are formed by the circumferential wall of a cylindrical body 10 which is molded to protrude inward in the radial direction of the cylindrical body 10. As illustrated in Figure 1, the valve seat surface 11 is a flat plane having an arc shape rather than an annular shape, the rectifying surface 12 is a surface that connects the ridge line 11R, which is the end of the inner valve seat surface 11 in the radial direction of the cylindrical body 10, to the inner circumferential surface of the cylindrical body 10, and the adjustment surface 13 is a surface that connects both ends 11E of the valve seat surface 11 in the circumferential direction of the cylindrical body 10, both ends of the rectifying surface in the circumferential direction of the cylindrical body 10, and the inner circumferential surface of the cylindrical body.

[0078] As described above, once the intended valve seat surface 11, flow straightening surface 12, and adjustment surface 13 are formed by the peripheral wall of the cylindrical body 10, which is shaped to protrude inward in the radial direction of the cylindrical body 10, the crushing die 40 is separated from the cylindrical body 10 and the first core 31 and the second core 32 are withdrawn from the end of the cylindrical body, thus completing the manufacturing of the valve body of the present invention.

[0079] Accordingly, in the fifth molding method, the first surface 31t and the second surface 32t are configured such that, after the completion of the third step performed in step S30, the first core 31 can be removed from one end of the cylindrical body 10 and the second core 32 can be removed from the other end of the cylindrical body 10. Specifically, the first core 31 and the second core 32 are configured to have a shape such that, for example, the shape of the internal space of the cylindrical body 10 after the completion of the third step is divided into two parts in the direction of the axis AX of the cylindrical body 10 by a surface that includes a line corresponding to the ridge line 11R of the valve seat surface 11. That is, the first surface 31t and the second surface 32t are surfaces that include a line corresponding to the ridge line 11R of the valve seat surface 11, and are surfaces that can divide the internal space of the cylindrical body 10 after the completion of the third step into two parts and separate them in the direction of the axis AX of the cylindrical body 10.

[0080] Furthermore, in the fifth molding method, the drive mechanism for inserting the first core 31 and the second core 32 into the cylindrical body 10, removing them from the cylindrical body 10, pressing them toward the cylindrical body 10 with the crushing die 40, and separating them from the cylindrical body 10 can be appropriately selected from various drive mechanisms known in the art, depending on the properties of the material constituting the cylindrical body 10 (e.g., mechanical strength and hardness), the thickness of the peripheral wall of the cylindrical body 10, and the shape and size of the valve seat surface 11, rectifying surface 12, and adjustment surface 13 to be formed. Typically, a press machine such as a hydraulic press is used as the drive mechanism.

[0081] Incidentally, as described in the description of the first valve body and the second valve body, in the mounting portion for attaching the pivot shaft and / or the drive mechanism for rotating the pivot shaft to the valve body of the present invention, a flat seating surface may be formed on the periphery of the shaft hole by, for example, press working, or the periphery of the shaft hole may be raised by, for example, burring. Such processing of the mounting portion may be performed before the fifth forming method, or it may be performed after the fifth forming method.

[0082] <effect> As described above, in the fifth embodiment of the present invention, the desired valve seat surface, flow straightening surface, and adjustment surface are integrally formed with the valve body by plastic deformation of a cylindrical body using the first core, the second core, and a crushing die. Therefore, compared to the case where a similar structure is formed by cutting as in the prior art described above, for example, the processing time is shorter, material loss is smaller, and manufacturing costs can be reduced. In other words, according to the fifth embodiment of the present invention, a valve body that can use a flat valve body and can achieve smooth fluid flow can be easily manufactured. Furthermore, in the fifth embodiment of the present invention, since the position and shape of the part to be molded are uniquely defined by the first core, the second core, and the crushing die, a valve seat surface and the like with accurate position, shape, and angle can be formed. Therefore, the valve body molding method according to the fifth embodiment of the present invention (fifth molding method) is particularly useful, for example, when it is necessary to form a plurality of valve seat surfaces having accurate relative positions, shapes, and parallelisms with each other.

[0083] 《Sixth Embodiment》 The molding method for a valve body according to the sixth embodiment of the present invention (hereinafter sometimes referred to as the "sixth molding method") will be described below with reference to the drawings.

[0084] As described in the description of the second valve body, in the second embodiment of the present invention, the valve seat angle is 90 degrees or more, and the flow straightening angle is greater than the valve seat angle. As a result, according to the second embodiment of the present invention, in addition to the effects achieved by the first embodiment described above, it is possible to more reliably reduce problems such as an increase in back pressure and / or the generation of abnormal noise caused by the generation of turbulence in the fluid flowing over the valve seat surface and the flow straightening surface when the valve is opened, thereby further enhancing the effect of achieving a smooth fluid flow. The sixth molding method is a molding method for a second valve body having such a configuration and being able to achieve such effects.

[0085] <composition> In other words, the sixth molding method is the fifth molding method described above, characterized in that it satisfies the requirements listed below in a cross-section of a plane including the axis of the cylindrical body. The first angle, which is the angle formed between the first molding surface of the first core and the adjacent outer surface at the base end of the first molding surface on the inner side in the radial direction of the cylindrical body, is 90 degrees or more. The second angle, which is the angle formed between the second molding surface of the second core and the adjacent outer surface at the base end of the second molding surface on the inner side in the radial direction of the cylindrical body, is larger than the first angle.

[0086] Figure 9 is a schematic diagram showing an example of the configuration of the first core and the second core used in the sixth molding method, and corresponds to Figure 8(b) which was referenced in the description of the fifth molding method. More specifically, Figure 9 is an enlarged cross-sectional view of the vicinity of the first molding surface 31a of the first core and the second molding surface 32a of the second core, when the first surface 31t, which is the tip surface of the first core 31, and the second surface 32t, which is the tip surface of the second core 32, are in contact with and fitted together inside the cylindrical body 10, as described in the description of the fifth molding method.

[0087] As illustrated in Figure 9, in the first core 31 used in the sixth molding method, the first angle θ1, which is the angle between the first molding surface 31a, which corresponds to the valve seat surface 11, and the adjacent outer peripheral surface on the base end side (upper side in the drawing) of the first molding surface 31a, on the inside (right side in the drawing) in the radial direction of the cylindrical body 10, is 90 degrees or more. In addition, in the second core 32 used in the sixth molding method, the second angle θ2, which is the angle between the second molding surface 32b, which corresponds to the rectifying surface 12, and the adjacent outer peripheral surface on the base end side of the second molding surface 32b, on the inside in the radial direction of the cylindrical body 10, is greater than the first angle θ1 (θ1 < θ2).

[0088] Although not shown in the diagram, as described in the explanation of the fifth molding method, in the third step, a crushing die (not shown) having a fourth molding surface which corresponds to the valve seat surface, rectifying surface, and adjustment surface to be molded, as well as the first core 31 and the second core 32, are arranged such that the peripheral wall of the cylindrical body 10 is sandwiched between the first molding surface 31a, the second molding surface 32b, and a third molding surface (not shown) and a fourth molding surface (not shown). That is, the fourth molding surface of the crushing die is formed to have a shape corresponding to the first molding surface 31a and the second molding surface 32b and the third molding surface (not shown) illustrated in Figure 9. Therefore, according to the sixth molding method, a second valve body having a valve seat angle of 90 degrees or more and a rectifying angle greater than the valve seat angle can be reliably and easily manufactured.

[0089] <effect> As described above, in the sixth embodiment of the present invention, the first angle, which is the angle formed on the inside of the cylindrical body in the radial direction between the first molded surface of the first core and the adjacent outer peripheral surface at the base end of the first molded surface, is 90 degrees or more. Furthermore, the second angle, which is the angle formed on the inside of the cylindrical body in the radial direction between the second molded surface of the second core and the adjacent outer peripheral surface at the base end of the second molded surface, is larger than the first angle. As a result, according to the sixth embodiment of the present invention, in addition to the effects achieved by the fifth embodiment described above, it is possible to more reliably reduce problems such as an increase in back pressure and / or the generation of abnormal noise caused by the generation of turbulence in the fluid flowing over the valve seat surface and the flow straightening surface when the valve is opened, and to further enhance the effect of achieving a smooth fluid flow.

[0090] 《Seventh Embodiment》 The molding method for a valve body according to the seventh embodiment of the present invention (hereinafter sometimes referred to as the "seventh molding method") will be described below with reference to the drawings.

[0091] As described in the description of the third valve body, from the viewpoint of improving sealing performance when the valve is closed, it is preferable that valve seat surfaces are formed on the inner circumferential surfaces of the cylindrical bodies on both sides of the pivot axis of the butterfly valve body. The seventh molding method is a molding method for a third valve body having such a configuration and achieving such effects.

[0092] The seventh molding method has the same configuration as the fifth molding method described with reference to the flowchart in Figure 7, except that the core and crushing mold are configured such that valve seat surfaces are formed on the inner circumferential surfaces of the cylindrical bodies on both sides of the pivot axis of the butterfly valve body. Therefore, the flow of each step included in the seventh molding method is the same as the flowchart illustrated in Figure 7, so please refer to the fifth molding method described with reference to the flowchart in Figure 7 for the flow of each step included in the seventh molding method.

[0093] On the other hand, please refer to Figure 10 for changes in the shape and positional relationship of each component during the process in which the third valve body is formed from the cylindrical state 10 by the seventh molding method. Figure 10 is a schematic cross-sectional view illustrating the shape and positional relationship of each component at the completion of the first to third steps included in the seventh molding method. The fourth molding method will be described below with reference to Figures 7 and 10. In the following description, parts not shown will also be denoted by reference numerals in parentheses for the purpose of facilitating understanding of this embodiment.

[0094] <composition> The seventh molding method is a molding method for the third valve body described above, and includes the first to third steps listed below, as illustrated in Figure 7.

[0095] First, in step S10, as illustrated in Figure 10(a), a first step is performed in which a third core 33 having a fifth molding surface 33a corresponding to the first valve seat surface 11a, a sixth molding surface 33b corresponding to the second rectifying surface 12b, and a seventh molding surface (33c) corresponding to a second adjustment surface (13b) not shown, is inserted from one end of the cylindrical body 10 (see the white arrow). Next, in step S20, as illustrated in Figure 10(b), a second step is performed in which a fourth core 34 having an eighth molding surface 34a corresponding to the second valve seat surface 11b, a ninth molding surface 34b corresponding to the first rectifying surface 11b, and a tenth molding surface (34c) corresponding to a first adjustment surface (13a) not shown, is inserted from the other end of the cylindrical body 10 (see the hatched arrow).

[0096] In the examples shown in Figures 7 and 10, the third core 33 was inserted from the upper end of the cylindrical body 10 toward Figure 10 in the first step (step S10), and the fourth core 33 was inserted from the lower end of the cylindrical body 10 toward Figure 10 in the next second step (step S20). However, conversely, the third core 33 may be inserted from the lower end of the cylindrical body 10 toward Figure 10 in the first step (step S10), and the fourth core 34 may be inserted from the upper end of the cylindrical body 10 toward Figure 10 in the next second step (step S20). Furthermore, the second step (step S20) may be performed before the first step (step S10). Moreover, the first step (step S10) and the second step (step S20) may be performed simultaneously.

[0097] Next, in step S30, as illustrated in Figure 10(c), a third step is performed in which the first crushing die 41 and the second crushing die 42 press the cylindrical body 10 from the outside to the inside while the third surface 33t, which is the tip surface of the third core 33, and the fourth surface 34t, which is the tip surface of the fourth core 34, are in contact with and fitted together inside the cylindrical body 10 (see the black arrows).

[0098] The first crushing die 41 has an eleventh molding surface 41a which corresponds to the first valve seat surface 11a, the first rectifying surface 12a, and the first adjustment surface (13a) (not shown). The third core 33 and the fourth core 34 and the first crushing die 41 are arranged so as to sandwich the peripheral wall of the cylindrical body 10 between the fifth molding surface 33a, the ninth molding surface 34b, the tenth molding surface (34c) (not shown), and the eleventh molding surface 41a.

[0099] On the other hand, the second crushing die 42 has a 12th molding surface 42a which corresponds to the second valve seat surface 11b, the second rectifying surface 12b, and a second adjustment surface (13b) not shown. The third core 33 and the fourth core 34 and the first crushing die 41 are arranged so as to sandwich the peripheral wall of the cylindrical body 10 between the 8th molding surface 34a, the 6th molding surface 33b, and the 7th molding surface (33c) not shown and the 12th molding surface 42a.

[0100] As described above, in the description relating to the valve body (third valve body) according to the third embodiment of the present invention, the valve seat surface 11, the rectifying surface 12, and the adjustment surface 13 are formed on the inner circumferential surfaces of the cylindrical bodies 10 on both sides of the pivot axis 21 of the butterfly valve body 20 as the first valve seat surface 11a, the first rectifying surface 12a, and the first adjustment surface 13a, and the second valve seat surface 11b, the second rectifying surface 12b, and the second adjustment surface 13b, respectively.

[0101] Figure 11 is a schematic diagram showing an example of a process performed after the third step is completed as described above. Once the desired first valve seat surface 11a, first rectifying surface 12a and first adjustment surface 13a, and the second valve seat surface 11b, second rectifying surface 12b and second adjustment surface 13b are formed as described above, the first crushing die 41 and the first crushing die 42 are separated from the cylindrical body 10 as illustrated in Figure 11(d) (see the black-filled arrow). Subsequently, the third core 33 and the fourth core 34 are pulled out from the end of the cylindrical body 10 as illustrated in Figure 11(e) (see the white-outlined arrow). As a result, as illustrated in Figure 11(f), a third valve body 103 is obtained in which the desired valve seat surface, rectifying surface and adjustment surface are integrally formed on the inner circumferential surfaces of the cylindrical bodies on both sides of the pivot axis of the butterfly valve body. Furthermore, the steps illustrated in Figure 11(d) and Figure 11(e) may be performed in the reverse order of those described above. Alternatively, the steps illustrated in Figure 11(d) and Figure 11(e) may be performed simultaneously.

[0102] As described above, in the seventh molding method as well, the third surface 33t and the fourth surface 34t are configured such that, after the completion of the third step performed in step S30, the third core 33 can be removed from one end of the cylindrical body 10 and the fourth core 34 can be removed from the other end of the cylindrical body 10.

[0103] Furthermore, as described in the description of the first to third valve bodies, in the mounting portion for attaching the pivot shaft and / or the drive mechanism for rotating the pivot shaft to the valve body of the present invention, a flat seating surface may be formed on the periphery of the shaft hole by, for example, press working, or the periphery of the shaft hole may be raised by, for example, burring. Such processing of the mounting portion may be performed before the seventh forming method, or it may be performed after the seventh forming method.

[0104] <effect> As described above, in the seventh embodiment of the present invention, the desired valve seat surface, flow straightening surface, and adjustment surface are integrally formed on the inner circumferential surfaces of the cylindrical bodies on both sides of the pivot axis of the butterfly valve body by plastic deformation of the cylindrical body using the third core and the fourth core and the first and second crushing dies. Therefore, according to the seventh embodiment of the present invention, it is possible to easily manufacture a valve body that can use a flat valve body and achieve smooth fluid flow, and the sealing performance when the valve is closed can be further improved.

[0105] 《Eighth Embodiment》 The molding method for a valve body according to the eighth embodiment of the present invention (hereinafter sometimes referred to as the "eighth molding method") will be described below with reference to the drawings.

[0106] As described in the explanation of the fourth valve body, in order to ensure the maximum fluid flow rate in the butterfly valve is as large as possible, it is preferable that the projected area of ​​the butterfly valve body when fully open be as small as possible in the projection view perpendicular to the direction of fluid flow. From this viewpoint, it is preferable that the first contact surface, which is the surface that contacts the first valve seat surface of the butterfly valve body, and the second contact surface, which is the surface that contacts the second valve seat surface, are parallel to each other. The eighth molding method is a molding method for a fourth valve body having such a configuration and being able to achieve such effects.

[0107] <composition> In other words, the eighth molding method is the seventh molding method described above, characterized in that the third surface 33t, which is the tip surface of the third core 33, and the fourth surface 34t, which is the tip surface of the fourth core 34, are in contact with and fitted together inside the cylindrical body 10, and the requirements D to F listed below are satisfied. In the following description, please refer to Figure 12 for the third core and the fourth core, and to Figure 5 for the butterfly valve body. Figure 12 is a schematic diagram showing an example of the configuration of the third core and the fourth core used in the eighth molding method.

[0108] Requirement D is that, as illustrated in Figure 12, the first molding plane PF1, which is the plane containing the fifth molding surface 33a of the third core 33, and the second molding plane PF2, which is the plane containing the eighth molding surface 34a of the fourth core 34, are parallel to each other and separated by a predetermined distance, the third distance D3. As described above, from the viewpoint of ensuring the maximum fluid flow rate in the butterfly valve as large as possible, it is preferable that the first contact surface, which is the surface that contacts the first valve seat surface of the butterfly valve body, and the second contact surface, which is the surface that contacts the second valve seat surface, are parallel to each other. Therefore, the first valve seat surface and the second valve seat surface formed on the fourth valve body are configured to fit a butterfly valve body having such a configuration. For this reason, the fifth molding surface 33a of the third core 33 and the eighth molding surface 34a of the fourth core 34 need to satisfy requirement D.

[0109] The first valve seat surface 11a and the second valve seat surface 11b formed on the fourth valve body 104 by the fifth molded surface 33a of the third core 33 and the eighth molded surface 34a of the fourth core 34, which satisfy requirement D, satisfy requirement A as described in the description of the fourth valve body. That is, as illustrated in Figure 5, the first valve seat plane PS1, which is the plane containing the first valve seat surface 11a, and the second valve seat plane PS2, which is the plane containing the second valve seat surface 11b, are parallel to each other and separated by a predetermined distance, the first distance D1. That is, the third distance D3, which is the distance between the first molded plane PF1 and the second molded plane PF2, is reflected, and the first distance D1, which is the distance between the first valve seat plane PS1 and the second valve seat plane PS2, becomes equal to the third distance (D1=D3).

[0110] However, in reality, the first distance D1 and the third distance D3 may not be exactly the same. For example, if a small gap occurs between the fifth molding surface 33a of the third core 33 and the inner circumferential surface of the cylindrical body 10, and a small gap occurs between the eighth molding surface 34a of the fourth core 34 and the inner circumferential surface of the cylindrical body 10 in the third step described above, the first distance D1 will be slightly larger than the third distance D3 by an amount corresponding to these gaps (D1 > D3).

[0111] Requirement E is that, as illustrated in Figure 5, the first contact plane PC1, which includes the first contact surface 22a that sits on the first valve seat surface 11a when the butterfly valve body 20 is closed, and the second contact plane PC2, which includes the second contact surface 22b that sits on the second valve seat surface 11b when the butterfly valve body 20 is closed, are parallel to each other and separated by a predetermined distance, the second distance D2. Requirement E is the same as requirement B described in the explanation of the fourth valve body, so a detailed explanation is omitted here.

[0112] Requirement F is that the third distance D3 is equal to the second distance D2. As described above, the third distance D3, which is the distance between the first forming plane PF1 and the second forming plane PF2, is reflected in the first distance D1, which is the distance between the first valve seat plane PS1 and the second valve seat plane PS2, so that it is equal to the third distance (D1=D3). Therefore, when requirement F is satisfied, if the third distance D3 is equal to the second distance D2, which is the distance between the first contact plane PC1 and the second contact plane PC2 of the butterfly valve body 20 (D2=D3), then as a result the first distance D1 becomes equal to the second distance (D1=D2).

[0113] <effect> As described above, in the eighth embodiment of the present invention, by satisfying requirements D to F described above, requirements A to C described in the description of the fourth valve body are also satisfied. That is, according to the eighth embodiment of the present invention, in addition to the effects achieved by the first to third embodiments described above, a fourth valve body can be reliably obtained that can reduce problems such as an increase in back pressure.

[0114] In order to explain the present invention, several embodiments having specific configurations have been described with reference to the accompanying drawings. However, the scope of the present invention should not be interpreted as being limited to these exemplary embodiments, and it goes without saying that modifications can be made as appropriate within the scope of the claims and the specification. For example, although the cross-sectional shape perpendicular to the axis of the valve body exemplified in this application is circular, the shape of the cross-sectional shape of the valve body is not limited to a circle, and may be an irregular shape such as an ellipse or oblong, as long as the function as a butterfly valve is not impaired. However, in this case, it goes without saying that the shape of the butterfly valve body must also correspond to the shape of the cross-sectional shape of the valve body. Furthermore, although the accompanying drawings of this application illustrate a valve body with an enlarged diameter portion formed at the end for the purpose of connecting to adjacent piping, the valve body may be formed by integrally forming the valve seat surface etc. on the piping itself. [Explanation of symbols]

[0115] 101, 102, 102', 103, 104, 104'… Valve body 10...Cylindrical body 11… Valve seat surface 11a...First valve seat surface 11b…Second valve seat surface 11R…Ridge 11E…Both ends PS1…1st valve seat plane PS2...2nd valve seat plane D1…First distance θs…Valve seat angle 12... Rectifying surface 12a...first rectification surface 12b…Second rectifying surface 12E…Both ends θa… Rectification angle 13…Adjustment surface 14… Shaft hole AX…Axis 14S…Seat 20...Butterfly valve body 21...Rotating axis 22a...first contact surface 22b…Second contact surface PC1…First contact plane PC2…Second contact plane D2…Second distance 31…First Neutron 31a…First forming surface 31t…Side 1 θ1…first angle 32…Second Neutron 32b…Second forming surface 32c… Third forming surface 32t… Page 2 θ2…Second angle 33…the third neutron 33a… Fifth forming surface 33b…6th Forming Surface 33c…7th forming surface 33t… Page 3 PF1…First forming plane 34…the fourth neutron 34a…8th forming surface 34b…9th forming surface 34c…10th forming surface 34t…Page 4 PF2…Second forming plane D3…3rd distance 40…collapse type 40a… Fourth forming surface 41…The first type of collapse 41a…11th forming surface 42…The second type of collapse 42a…12th forming surface

Claims

1. A valve body comprising a cylindrical body rotatably housing a butterfly valve element, wherein a valve seat surface is integrally formed that protrudes radially inward from the cylindrical body, thereby constituting a butterfly valve, The valve seat surface is formed by the peripheral wall of the cylindrical body which is shaped to protrude inward in the radial direction of the cylindrical body, and is a flat surface having an arc shape rather than an annular shape. A flow-straightening surface, which is a surface connecting the ridge line that is the end of the valve seat surface on the inner side of the cylindrical body in the radial direction and the inner circumferential surface of the cylindrical body, is formed on the downstream side of the valve seat surface in the closing direction, which is the rotation direction when the butterfly valve body is closed. Adjustment surfaces are formed on the cylindrical body, connecting both ends of the valve seat surface in the circumferential direction, both ends of the rectifying surface in the circumferential direction, and the inner circumferential surface of the cylindrical body. A valve body characterized by the following features.

2. A valve body according to claim 1, In a cross-section of the cylindrical body that includes the axis, The valve seat angle, which is the angle formed between the valve seat surface and the inner circumferential surface of the cylindrical body adjacent to the valve seat surface on the inner side in the radial direction of the cylindrical body, is 90 degrees or more. The rectification angle, which is the angle formed between the rectifying surface and the inner circumferential surface of the cylindrical body adjacent to the rectifying surface on the inner side of the cylindrical body in the radial direction, is greater than the valve seat angle. A valve body characterized by the following features.

3. A valve body according to claim 1 or claim 2, The valve seat surface, the straightening surface, and the adjustment surface are formed on the inner circumferential surfaces of the cylindrical body on both sides of the pivot axis of the butterfly valve body, as a first valve seat surface, a first straightening surface, and a first adjustment surface, and as a second valve seat surface, a second straightening surface, and a second adjustment surface, respectively. A valve body characterized by the following features.

4. A valve body according to claim 3, The first valve seat plane, which includes the first valve seat surface, and the second valve seat plane, which includes the second valve seat surface, are parallel to each other and separated by a predetermined distance, the first distance. A first contact plane, which includes a first contact surface that sits on the first valve seat surface when the butterfly valve body is closed, and a second contact plane, which includes a second contact surface that sits on the second valve seat surface when the butterfly valve body is closed, are parallel to each other and separated by a predetermined distance, a second distance. The first distance is equal to the second distance. A valve body characterized by the following features.

5. A method for forming a valve body according to claim 1, A first step involves inserting a first core having a first molded surface which corresponds to the valve seat surface, from one end of the cylindrical body. A second step of inserting a second core, which has a second molding surface corresponding to the rectifying surface and a third molding surface corresponding to the adjustment surface, from the other end of the cylindrical body, and In a state in which the first surface, which is the tip surface of the first core, and the second surface, which is the tip surface of the second core, are in contact with and fitted together inside the cylindrical body, a crushing die having a fourth molding surface, which is a surface corresponding to the valve seat surface, the rectifying surface, and the adjustment surface, is pressed from the outside to the inside of the cylindrical body so as to sandwich the peripheral wall of the cylindrical body between the first molding surface, the second molding surface, the third molding surface, and the fourth molding surface. Includes, The first and second surfaces are configured such that, after the completion of the third step, the first core can be removed from one end of the cylindrical body and the second core can be removed from the other end of the cylindrical body. A method for molding a valve body, characterized by the features described above.

6. A method for forming a valve body according to claim 5, In a cross-section of the cylindrical body that includes the axis, The first angle, which is the angle formed between the first molded surface of the first core and the adjacent outer peripheral surface on the base end side of the first molded surface on the inner side in the radial direction of the cylindrical body, is 90 degrees or more. The second angle, which is the angle formed between the second molding surface of the second core and the adjacent outer peripheral surface at the base end of the second molding surface on the inner side in the radial direction of the cylindrical body, is greater than the first angle. A method for molding a valve body, characterized by the features described above.

7. A method for forming a valve body according to claim 3, A first step of inserting a third core, having a fifth molding surface which corresponds to the first valve seat surface, a sixth molding surface which corresponds to the second rectifying surface, and a seventh molding surface which corresponds to the second adjustment surface, from one end of the cylindrical body. A second step of inserting a fourth core, which has an eighth molding surface corresponding to the second valve seat surface, a ninth molding surface corresponding to the first rectifying surface, and a tenth molding surface corresponding to the first adjustment surface, from the other end of the cylindrical body, and In a state where the third surface, which is the tip surface of the third core, and the fourth surface, which is the tip surface of the fourth core, are in contact with and fitted together inside the cylindrical body, a first crushing die having an eleventh molding surface, which corresponds to the first valve seat surface, the second straightening surface, and the second adjustment surface, is pressed from the outside to the inside of the cylindrical body so as to sandwich the peripheral wall of the cylindrical body between the fifth molding surface, the sixth molding surface, the seventh molding surface and the eleventh molding surface, and a second crushing die having a twelfth molding surface, which corresponds to the second valve seat surface, the first straightening surface, and the first adjustment surface, is pressed from the outside to the inside of the cylindrical body so as to sandwich the peripheral wall of the cylindrical body between the eighth molding surface, the ninth molding surface, the tenth molding surface and the twelfth molding surface, Includes, The third and fourth surfaces are configured such that, after the completion of the third step, the third core can be removed from one end of the cylindrical body and the fourth core can be removed from the other end of the cylindrical body. A method for molding a valve body, characterized by the features described above.

8. A method for forming a valve body according to claim 7, In a state where the third surface, which is the tip surface of the third core, and the fourth surface, which is the tip surface of the fourth core, are in contact with and fitted together inside the cylindrical body, The first molding plane, which includes the fifth molding surface of the third core, and the second molding plane, which includes the eighth molding surface of the fourth core, are parallel to each other and separated by a predetermined distance, which is a third distance. A first contact plane, which includes a first contact surface that sits on the first valve seat surface when the butterfly valve body is closed, and a second contact plane, which includes a second contact surface that sits on the second valve seat surface when the butterfly valve body is closed, are parallel to each other and separated by a predetermined distance, a second distance. The third distance is equal to the second distance. A method for molding a valve body, characterized by the features described above.

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