Valve body and forming method of 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 technology]

[0002] For example, in a valve body that houses a butterfly valve that is connected to an exhaust pipe of an internal combustion engine and / or piping for building facilities to control the flow rate of a fluid, there is a demand for, for example, weight reduction and / or improvement in reliability, etc. In this regard, a technique is known in the art in which a valve seat surface (seat surface) on which a valve disc sits is integrally formed with the valve body on the peripheral wall of the metallic valve body having a cylindrical shape.

[0003] For example, Patent Document 1 (Japanese Utility Model Application Laid-Open Publication No. 6-80840) discloses a butterfly valve in which an annular bead portion 4a that protrudes inward over the entire circumference is integrally formed with a cylindrical valve body (as an exhaust pipe 4) by plastic processing, and a butterfly valve element 3 bent into a Z-shape is brought into contact with the side of the bead portion 4a to close the valve. In this configuration, the side of the bead portion 4a over the entire circumference becomes the valve seat surface. As a result, the mount portion of the rotating shaft 2, including the seat surface (as the flat portions 4d, 4e that fix the bearing cases 6, 7) for attaching the rotating shaft 2 to the exhaust pipe 4, and the bead portion 4a interfere with each other. As a result, the valve shaft (as the rotating shaft 2) of the butterfly valve element 3 becomes shorter, and the configuration of the mount portion of the rotating shaft 2 is also restricted.

[0004] Furthermore, in terms of strength and fluid dynamics, it is desirable for the butterfly valve to have a flat butterfly valve body 3, but since the bead portion 4a has a certain width (dimension in the axial direction of the exhaust pipe 4), the first valve body 3a and the second valve body 3b present on both sides of the rotation shaft 2 of the butterfly valve body 3 must be offset by the amount of said width. For this reason, the cross section of the butterfly valve body 3 taken on a plane perpendicular to the rotation shaft 2 has a Z-shape.

[0005] Meanwhile, Patent Document 2 (Japanese Patent No. 4578923) discloses a structure in which the peripheral edge of the valve body on one side relative to the pivot shaft abuts against a first step provided on the inner peripheral surface of the pipe, and the peripheral edge of the valve body on the other side relative to the pivot shaft abuts against a second step provided on the inner peripheral surface of the pipe, thereby blocking the pipe. In this structure, the first step and the second step are not continuous annularly around the entire circumference as in Patent Document 1 mentioned above, but are formed only on different sides of the pivot shaft, respectively, and it is said that this structure can suppress the reduction in the cross-sectional area of ​​the flow passage compared to the butterfly valve disclosed in Patent Document 1 mentioned above.

[0006] However, the process of forming a step on the inner surface of a tube by cutting takes longer to process and results in greater material loss than the process of forming a step by plastic processing as in Patent Document 1 mentioned above, and there are concerns that this may result in increased manufacturing costs.

[0007] That is, there is a need in the art for a valve body that allows the use of a flat valve element, achieves smooth fluid flow, and is easily manufactured. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Utility Model Application Publication No. 6-80840 [Patent Document 2] Patent No. 4578923 [Patent Document 3] Patent No. 6353791 Summary of the Invention [Problem to be solved by the invention]

[0009] As discussed above, there is a need in the art for a valve body that allows the use of a flat valve element, achieves smooth fluid flow, and is easily manufactured. [Means for solving the problem]

[0010] In view of the above problems, the inventors conducted extensive research and discovered that the above problems can be solved by forming an arc-shaped valve seat surface integrally with the valve body of a butterfly valve by causing the peripheral wall to protrude inwards, forming a gentle flow straightening surface downstream of the valve seat surface in the rotational direction of the valve body when the valve is closed, and providing an adjustment surface which is an area 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, may be referred to as the "valve body of the present invention") is a valve body that rotatably accommodates a butterfly valve element inside a cylindrical body and is integrally formed with a valve seat surface that protrudes radially inward of the cylindrical body to constitute a butterfly valve. The valve seat surface is formed by the peripheral wall of the cylindrical body molded to protrude radially inward of the cylindrical body, and is a flat surface having an arc-like shape rather than an annular shape.

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

[0013] On the other hand, the molding method for the valve body according to the present invention (hereinafter, may be referred to as the "molding method of the present invention") is a molding method for the valve body according to the present invention described above, and includes the first to third steps listed below.

[0014] The first step is a step of inserting a first core having a first molding surface that corresponds to the valve seat surface from one end of a cylindrical body. The second step is a step of inserting a second core having a second molding surface corresponding to the flow straightening surface and a third molding surface corresponding to the adjustment surface from the other end of the cylindrical body. The third step is a step in which, 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 abutting and fitting to each other inside the cylindrical body, a crushing die having a fourth molding surface which is a surface corresponding to the valve seat surface, the straightening 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, and the third molding surface and the fourth molding surface.

[0015] Furthermore, in the molding method of the present invention, the first surface and the second surface are configured so that after 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. Effect 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 peripheral wall of the cylindrical body molded to protrude inward in the radial direction of the cylindrical body. Such a valve seat surface can be molded by plastic processing, as in the molding method of the present invention described above. Therefore, compared to the structure disclosed in the above-mentioned Patent Document 2, in which a step is formed on the inner peripheral surface of the pipe by cutting processing, for example, the processing time is shorter, material loss is smaller, and manufacturing costs can be reduced.

[0017] In addition, the valve seat surface of the valve body according to the present invention is not annular but is a flat surface having an arc shape, so there is no interference between the mount for attaching the pivot shaft to the valve body and the valve seat surface, and there is no need to shorten the pivot shaft of the butterfly valve body as in the butterfly valve disclosed in the above-mentioned Patent Document 1, and there are no restrictions on the configuration of the mount for attaching the pivot shaft to the valve body.

[0018] Furthermore, unlike the butterfly valve disclosed in the above-mentioned Patent Document 1, the valve seat is not formed by the side of a bead portion formed around the entire circumference of the valve body and having a predetermined width. Therefore, it is not necessary for the butterfly valve element to seat on a valve seat surface that is offset by a predetermined distance in the axial direction of the valve body, and it is not necessary to use a butterfly valve element having a Z-shaped cross section. In other words, in the valve body of the present invention, a flat butterfly valve element, which is desirable in terms of strength and fluid dynamics, can be used.

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

[0020] That is, according to the present invention, it is possible to provide a valve body which allows the use of a flat valve element, enables a smooth flow of fluid, and can be easily manufactured.

[0021] Other objects, features and attendant advantages of the present invention will become readily apparent from the following description of the embodiments of the present invention which are given with reference to the accompanying drawings. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 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. [Diagram 2] FIG. 6 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. [Diagram 3] FIG. 11 is a schematic diagram showing an example of the configuration of a second valve body according to another embodiment. [Figure 4] FIG. 11 is a schematic diagram showing an example of the configuration of a valve body (third valve body) according to a third embodiment of the present invention. [Diagram 5] FIG. 11 is a schematic diagram showing an example of the configuration of a valve body (fourth valve body) according to a fourth embodiment of the present invention. [Figure 6] FIG. 11 is a schematic diagram showing an example of the configuration of a fourth valve body according to another embodiment. [Figure 7] 13 is a flowchart illustrating the flow of each step included in a molding method for a valve body according to a fifth embodiment of the present invention (fifth molding method). [Figure 8] 13A to 13C are schematic cross-sectional views illustrating the shapes and positional relationships of the members upon completion of the first to third steps included in the fifth molding method. [Figure 9] FIG. 13 is a schematic diagram showing an example of the configuration of a first core and a second core used in a molding method (sixth molding method) for a valve body according to a sixth embodiment of the present invention. [Figure 10] FIG. 13 is a schematic cross-sectional view illustrating the shapes and positional relationships of the members upon completion of the first to third steps included in the molding method for a valve body according to the seventh embodiment of the present invention (seventh molding method). [Figure 11] FIG. 13 is a schematic diagram showing an example of a step that is performed after the third step included in the seventh molding method is completed. [Figure 12] FIG. 13 is a schematic diagram showing an example of the configuration of a third core and a fourth core used in a molding method for a valve body according to an eighth embodiment of the present invention (eighth molding method). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0024] <composition> Fig. 1 is a schematic perspective view showing an example of the configuration of a first valve body. The first valve body 101 shown in Fig. 1 is a valve body that rotatably accommodates a butterfly valve body (not shown) inside a cylindrical body 10 and is integrally formed with a valve seat surface 11 that protrudes toward the inside in the radial direction of the cylindrical body 10 to form a butterfly valve. Although the valve seat surface 11 is formed inside the cylindrical body 10, since it is difficult to illustrate the inside of the cylindrical body 10, in Fig. 1, a part corresponding to the valve seat surface 11 on the outer circumferential surface of the cylindrical body 10 is given a reference number. The same applies to the ridge line of the valve seat surface 11, both ends of the valve seat surface 11, the flow straightening surface, both ends of the flow 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 usage 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, aluminum, or an alloy containing these metals, such as stainless steel.

[0026] The valve seat surface 11 is formed by the peripheral wall of the cylindrical body 10 which is formed so as to protrude toward the inside in the radial direction of the cylindrical body 10. Specifically, as described later, such a valve seat surface 11 can be formed by plastic processing of the cylindrical body 10. Therefore, compared to the case where a step is formed on the inner peripheral surface of the tube by cutting processing as in the structure disclosed in the above-mentioned Patent Document 2, for example, the processing time is shorter, material loss is smaller, and manufacturing costs can be reduced.

[0027] 1, the valve seat surface 11 is a flat surface having an arc shape rather than an annular shape. That is, the valve seat surface 11 is not formed over the entire circumference of the cylindrical body 10. Therefore, there is no interference between the valve seat surface 11 and a mount portion (not shown) for attaching a rotating shaft (not shown) to the first valve body 101, so there is no need to shorten the rotating shaft or there are no restrictions on the configuration of the mount portion for attaching the rotating 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 of a bead portion having a predetermined width formed around the entire circumference of the valve body as in the butterfly valve disclosed in the above-mentioned Patent Document 1. Therefore, even when two valve seat surfaces 11 are provided on both sides of the pivot shaft, these valve seat surfaces 11 can be formed so that the plane including both valve seat surfaces 11 exists in the same plane, so it is not necessarily necessary to use a butterfly valve element having a Z-shaped cross section. In other words, in the valve body of the present invention, a flat butterfly valve element, which is desirable in terms of strength and fluid dynamics, can be used.

[0029] Furthermore, in the first valve body 101, a straightening surface 12, which is a surface connecting a 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, is formed on the downstream side (the front side in Figure 1) of the valve seat surface 11 in the valve closing direction, which is the rotation direction of the butterfly valve body when the valve is closed.

[0030] In addition, an adjustment surface 13 is formed, which is a surface connecting both ends 11E of the valve seat surface 11 in the circumferential direction of the cylindrical body 10, both ends 12E of the flow straightening 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 an area surrounded by 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, and has a substantially triangular shape in the example shown in FIG.

[0031] In the first valve body 101 shown in Fig. 1, an axial hole 14 for inserting a rotating shaft of a butterfly valve element (not shown) is drilled in the peripheral wall of the cylindrical body 10. However, the configuration of a mount for attaching the rotating shaft and / or a drive mechanism for rotating the rotating shaft to the first valve body 101 is not limited to the example shown in Fig. 1, and as will be described later, a flat seat surface may be formed on the peripheral edge of the axial hole 14 by, for example, pressing, or the peripheral edge of the axial hole 14 may be raised by, for example, burring.

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

[0033] From the viewpoint of reducing the occurrence of turbulence in the flow of the fluid 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 straightening surface 12. More preferably, in a cross section taken along a plane including the axis of the cylindrical body 10, there is no inflection point in the straightening surface 12. Similarly, from the viewpoint of reducing the occurrence of turbulence in the flow of the fluid 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 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 taken along a plane including the axis of the cylindrical body 10, there is no inflection point in the adjustment surface 13.

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

[0035] Second Embodiment A valve body according to a second embodiment of the present invention (hereinafter, may be referred to as a "second valve body") will be described below with reference to the drawings.

[0036] In the butterfly valve disclosed in the above-mentioned Patent Document 1 and the structure disclosed in the above-mentioned 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 (the 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 greatly protrude the valve seat surface 11 toward the inside of the cylindrical body 10 to increase the overlapping area between the butterfly valve element and the valve seat surface 11. Also, in order to avoid contact between the butterfly valve element and the inner peripheral surface of the cylindrical body 10 in the case where thermal expansion of the butterfly valve element and / or the cylindrical body 10 occurs at high temperatures, it is necessary to ensure a certain degree of clearance between the butterfly valve element seated (in contact) on the valve seat surface when the valve is closed and the inner peripheral surface of the cylindrical body 10. From this viewpoint as well, it is necessary to greatly protrude the valve seat surface 11 toward the inside of the cylindrical body 10.

[0038] However, when the valve seat surface 11 is largely protruded toward the inside of the cylindrical body 10 as described above, the flow path cross-sectional area in that portion becomes smaller and the step between the inner peripheral surface of the cylindrical body 10 adjacent to the valve seat surface 11 and the ridge line 11R of the valve seat surface 11 becomes larger. As a result, the flow of the fluid flowing through that portion becomes turbulent, and problems such as an increase in back pressure and / or generation of abnormal noise may occur.

[0039] In the technical field, it is known to provide a valve seat surface inclined with respect to the axial direction of a cylindrical valve body as a means for solving the above-mentioned problems. For example, when forming a valve seat surface by plastic processing, 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 periphery of the end of the cylindrical valve body by press processing. However, a technology for forming a valve seat surface inclined with respect to the axial direction of the cylindrical valve body by plastic processing not at the end of the cylindrical valve body but in the middle of the valve body is not yet known.

[0040] As described 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 requires, for example, a longer processing time and a larger loss of material than the process of forming the valve seat surface by plastic processing, and there is a concern that the manufacturing cost will increase. Furthermore, when forming a valve seat surface inclined with respect to the axial direction of the valve body, there is an even greater concern that the manufacturing cost will increase due to, for example, the complexity of processing control, the further prolongation of processing time, and the further increase in material loss.

[0041] <composition> The second valve body is the above-mentioned first valve body, characterized in that it satisfies the requirements listed below in a cross section taken along a plane including the axis of the cylindrical body. A valve seat angle, which is an angle formed between the valve seat surface and an 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. A straightening angle, which is an angle formed between the straightening surface and an inner circumferential surface of the cylindrical body adjacent to the straightening surface on the inside in the radial direction of the cylindrical body, is larger than the valve seat angle.

[0042] Fig. 2 is a schematic diagram showing an example of the configuration of the second valve body. Fig. 2(a) is a schematic front view of the second valve body 102 observed from one end side, (b) is a schematic side view of the cross section of the second valve body 102 taken along a plane including the line AA and the axis AX of the cylindrical body 10 shown in (a) observed from the side, and (c) is a schematic side view of the cross section of the second valve body 102 taken along a plane including the line BB and the axis AX of the cylindrical body 10 shown in (a) observed from the side.

[0043] In the second valve body 102, as illustrated in FIG. 2B, in a cross section taken along a plane including the axis AX of the cylindrical body 10, the valve seat angle θs, which is an angle between the valve seat surface 11 and the inner peripheral surface of the cylindrical body adjacent to the valve seat surface 11 on the inside in the radial direction of the cylindrical body 10, is an obtuse angle (greater than 90 degrees). As a result, even if the area of ​​the valve seat surface 11 is increased for the purpose of improving the sealing performance when the valve is closed and / or ensuring the clearance between the butterfly valve element and the inner peripheral 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 when 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 flow of the fluid flowing through the portion can be reduced.

[0044] In addition, the straightening angle θa, which is the angle between the straightening surface 12 and the inner circumferential surface of the cylindrical body 10 adjacent to the straightening surface 12 on the inside in the radial direction of the cylindrical body 10, is larger than the valve seat angle θs (θa>θs). That is, the portion adjacent to the valve seat surface 11 across 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, it is possible to 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 ridge line 11R of the valve seat surface 11 when the valve is opened.

[0045] As described above, the configuration of the mount portion for mounting the rotating shaft and / or the drive mechanism for rotating the rotating shaft to the cylindrical body 10 is not limited to the example shown in FIG. 1 referred to in the description of the first valve body 101. As illustrated in FIG. 2(c), a flat seat surface 14S may be formed on the periphery of the shaft hole 14 by, for example, pressing, or the periphery of the shaft hole 14 may be raised by, for example, burring. In the example shown in FIG. 2(b) and FIG. 2(c), an expanded diameter portion having a larger diameter than other portions is formed on one end of the cylindrical body 10 (the end on the right side of the drawing). Such an expanded diameter portion is provided for the purpose of connecting to other adjacent members, such as an exhaust pipe of an internal combustion engine and / or piping for building facilities. However, such an expanded diameter portion is not an essential component of the valve body according to the present invention.

[0046] As described above, in the second valve body, the valve seat angle, which is the angle 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 valve seat angle being 90 degrees. FIG. 3 is a schematic diagram showing an example of the configuration of a second valve body according to another embodiment. More specifically, FIG. 3 is a schematic side view of a cross section of the second valve body 102' observed from the side along a plane including the axis AX of the cylindrical body 10 and passing through the center of the flow straightening surface 12 in the circumferential direction of the cylindrical body 10, similar to FIG. 2(b).

[0047] 3, in the second valve body 102', in a cross section taken along a plane including the axis AX of the cylindrical body 10, 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 on the inside in the radial direction of the cylindrical body 10, is a right angle (equal to 90 degrees). In the case where problems such as an increase in back pressure and / or abnormal noise caused by turbulence in the flow of the fluid flowing through the portion remain within an acceptable range even if the amount of protrusion of the valve seat surface 11 is increased, the valve seat angle θs may be 90 degrees in this way.

[0048] 2(b), the second valve body 102' illustrated in Fig. 3 has a rectification angle θa larger than the valve seat angle θs (θa>θs). That is, the portion adjacent to the valve seat surface 11 across the ridge 11R of the valve seat surface 11 is formed as a gentle slope. Therefore, compared to the case where the portion is formed as a steep step, 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 ridge 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 straightening angle is larger 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, 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 straightening surface when the valve is opened can be more reliably reduced, and the effect of achieving a smooth flow of the fluid can be further enhanced.

[0050] Third Embodiment Hereinafter, a valve body according to a third embodiment of the present invention (hereinafter, may be referred to as a "third valve body") will be described with reference to the drawings.

[0051] When the butterfly valve is closed, the surface of the butterfly valve body that abuts against the valve seat surface (hereinafter, may be referred to as the "abutment surface") comes into contact with the valve seat surface, causing the butterfly valve body to stop rotating, thereby minimizing the flow rate of the fluid flowing inside the cylindrical body. Since the flow rate of the fluid when the valve is closed is affected by the distance (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 the valve seat surface so that the rotation of the butterfly valve body stops at an angle at which the flow rate of the fluid when the valve is closed is the desired value.

[0052] To achieve the above object, it is sufficient that one valve seat surface is formed on the inner peripheral surface of the cylindrical body on one side of the rotation axis of the butterfly valve element. However, from the viewpoint of improving the sealing performance when the valve is closed, it is preferable that a valve seat surface is formed on each of the inner peripheral surfaces of the cylindrical body on both sides of the rotation axis of the butterfly valve element.

[0053] <composition> Therefore, the third valve body is the above-mentioned first valve body or second valve body, characterized in that the valve seat surface, the flow straightening surface and the adjustment surface are formed as a first valve seat surface, a first flow straightening surface and a first adjustment surface, and a second valve seat surface, a second flow straightening surface and a second adjustment surface, respectively, on the inner circumferential surface of a cylindrical body on both sides of the rotation axis of the butterfly valve body.

[0054] 2 and 3, the second valve body 102 and the second valve body 102' described above have the valve seat surface 11, the flow straightening surface 12, and the adjustment surface 13 formed on the inner circumferential surface of the cylindrical body 10 on both sides of the rotation axis of the butterfly valve element (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 as a third valve body.

[0055] In the second valve body 102 and the second valve body 102', the two valve seat surfaces 11 have the same valve seat angle θs, and the planes including the two valve seat surfaces 11 are parallel to each other. However, the two valve seat surfaces 11 (planes including the two valve seat surfaces 11) 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 from each other.

[0056] Fig. 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, Fig. 4 is a schematic side view of a cross section of the third valve body 103 observed from the side along a plane including the axis AX of the cylindrical body 10 and passing through the center of the flow straightening surface 12 in the circumferential direction of the cylindrical body 10, similar to Fig. 2(b) and Fig. 3. As illustrated in Fig. 4, in the third valve body 103, the valve seat surface 11, the flow straightening surface 12, and the adjustment surface 13 are formed on the inner peripheral surface of the cylindrical body 10 on both sides of the rotation axis 21 of the butterfly valve body 20, respectively.

[0057] 4, the plate-like member (disk) constituting the butterfly valve element 20 housed inside the third valve body 103 is bent in the vicinity of the rotation axis 21, and one side of the disk on the rotation axis 21 is inclined relative to the other side. In accordance with this butterfly valve element 20, if the valve seat surface 11 on the upper side as viewed in the drawing is taken as the first valve seat surface and the valve seat surface 11 on the lower side as viewed in the drawing is taken as the second valve seat surface, the valve seat angle of the first valve seat surface and the valve seat angle of the second valve seat surface are different. In other words, these two valve seat surfaces (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 peripheral surface of the cylindrical body on both sides of the rotation axis of the butterfly valve element. As a result, according to the third embodiment of the present invention, in addition to the effects achieved by the first and second embodiments described above, it is possible to improve the sealing performance when the valve is closed.

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

[0060] In the third valve body 103 shown in Fig. 4, the plate-like member (disk) constituting the butterfly valve element 20 is bent in the vicinity of the rotation axis 21, and one side of the disk is inclined relative to the other side of the rotation axis 21. When the disk is inclined relative to the other side of the rotation axis 21 in this manner, the larger the inclination angle, the larger the projected area of ​​the butterfly valve element 20 in a vertical projection in the direction of the fluid flow inside the third valve body 103 (i.e., inside the cylindrical body 10). This reduces the flow path cross-sectional area in that portion, which can cause problems such as an increase in back pressure.

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

[0062] <composition> That is, the fourth valve body is the above-mentioned third valve body, and is characterized in that it satisfies the following requirements A to C. Requirement A is that a first valve seat plane, which is a plane including the first valve seat surface, and a second valve seat plane, which is a plane including the second valve seat surface, are parallel to each other and are separated by a predetermined first distance. Requirement B is that a first abutment plane, which is a plane including a first abutment surface that seats on the first valve seat surface when the butterfly valve body is closed, and a second abutment plane, which is a plane including a second abutment surface that seats on the second valve seat surface when the butterfly valve body is closed, are parallel to each other and are separated by a predetermined second distance. Requirement C is that the first distance is equal to the second distance.

[0063] Fig. 5 is a schematic diagram showing an example of the configuration of the fourth valve body. More specifically, Fig. 5 is a schematic side view of a cross section of the fourth valve body 104 taken along a plane including the axis AX of the cylindrical body 10 and passing through the center of the flow straightening surface 12 in the circumferential direction of the cylindrical body 10, as in Fig. 2(b), Fig. 3 and Fig. 4, as observed from the side. However, in Fig. 5, the axis AX of the cylindrical body 10 is omitted due to drawing space limitations. Also, the butterfly valve element 20 in the closed state is drawn by a solid line, and the butterfly valve element 20 in the fully open state is drawn by a dashed line.

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

[0065] That is, 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 abutment plane PC1 and the second abutment plane PC2 in the butterfly valve element 20. As illustrated in FIG. 5, the butterfly valve element 20 accommodated in the fourth valve body 104 has a Z-shaped cross section taken along a plane perpendicular to the rotation shaft 21. In this case, the second distance D2 is the sum of the thickness of the portion including the first abutment surface 22a of the plate-like member (disk) constituting the butterfly valve element 20, the thickness of the portion including the second abutment surface 22b, and the size of the bent portion fixing the disk to the rotation shaft 21 in the direction perpendicular to the first abutment surface 22a and the second abutment surface 22b. The first distance D1 is set to match the second distance D2 determined in this manner.

[0066] As mentioned at the beginning of this specification, it is desirable for the butterfly valve to have a flat butterfly valve body in terms of strength and fluid dynamics. Figure 6 is a schematic diagram showing an example of the configuration of a fourth valve body according to another embodiment. More specifically, like Figure 2(b) and Figures 3 to 5, Figure 6 is a schematic side view of a cross section of the fourth valve body 104' taken along a plane including the axis AX of the cylindrical body 10 and passing through the center of the flow straightening surface 12 in the circumferential direction of the cylindrical body 10, as observed from the side. However, like Figure 5, the axis AX of the cylindrical body 10 is omitted in Figure 6 due to drawing space limitations. Also, the butterfly valve body 20 in the closed state is drawn by a solid line, and the butterfly valve body 20 in the fully open state is drawn by a dashed line.

[0067] 6, the fourth valve body 104' satisfies the requirements that the fourth valve body 104 described above must satisfy, and accommodates the flat butterfly valve element 20. In this case, the thickness of the plate-like member (disk) that constitutes the butterfly valve element 20 becomes the second distance D2, and the first distance D1 is set so as to coincide with the second distance D2 determined in this manner.

[0068] As a result of the above, when the valve is closed, the first contact surface 22a of the butterfly valve element 20 can be seated on the first valve seat surface 11a and the second contact surface 22b of the butterfly valve element 20 can be seated on the second valve seat surface 11b at the same time, as depicted by solid lines in Figures 5 and 6. On the other hand, when the valve is fully open, as depicted by dashed lines in Figures 5 and 6, the projected area of ​​the butterfly valve element 20 in a vertical projection in the direction of fluid flow 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 practice, the first distance D1 and the second distance D2 may not strictly match. For example, when a small gap occurs between the first valve seating surface 11a and the first contact surface 22a and between the second valve seating surface 11b and the second contact surface 22b when the valve is closed, the first distance D1 becomes 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 (first distance) between the first and second valve seat planes parallel to each other of the valve body is equal to the distance (second distance) between the first and second abutment planes parallel to each other of the butterfly valve element. This allows the butterfly valve element to be seated on the first and second valve seat surfaces simultaneously when the valve is closed. On the other hand, when the valve is fully open, the projected area of ​​the butterfly valve element in the vertical projection in the direction of the fluid flow inside the valve body can be made as small as possible, thereby ensuring the flow passage cross-sectional area in that portion as large as possible. 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 as described above, but also to a molding method for the valve body. Hereinafter, a molding method for a valve body according to a fifth embodiment of the present invention (hereinafter, sometimes referred to as a "fifth molding method") will be described with reference to the drawings.

[0072] Fig. 7 is a flow chart illustrating the flow of each step included in the fifth molding method. Fig. 8 is a schematic cross-sectional view illustrating the shape and positional relationship of each member at the completion of the first to third steps included in the fifth molding method. Note that Fig. 8 illustrates only the portion of the cylindrical body 10 on the left side of the axis AX as viewed in the drawing. Furthermore, in the following description, for the purpose of making the present embodiment easier to understand, the portions not shown are also denoted by reference characters in parentheses.

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

[0074] First, in step S10, as shown in (a) of Fig. 8, a first step is performed in which a first core 31 having a first molding surface 31a corresponding to the valve seat surface 11 is inserted from one end of the cylindrical body 10 (see the outline arrow). Next, in step S20, as shown in (b) of Fig. 8, a second core 32 having a second molding surface 32b corresponding to the flow straightening surface 12 and a third molding surface (32c) corresponding to the adjustment surface (13), not shown, is inserted from the other end of the cylindrical body 10 (see the arrow hatched with diagonal lines).

[0075] In the example shown in Figs. 7 and 8, the first core 31 is inserted from the upper end of the cylindrical body 10 facing Fig. 8 in the first step (step S10), and the second core 32 is inserted from the lower end of the cylindrical body 10 facing Fig. 8 in the next second step (step S20). However, on the contrary, the first core 31 may be inserted from the lower end of the cylindrical body 10 facing Fig. 8 in the first step (step S10), and the second core 32 may be inserted from the upper end of the cylindrical body 10 facing Fig. 8 in the next second step (step S20). Also, the second step (step S20) may be performed before performing the first step (step S10). Furthermore, the first step (step S10) and the second step (step S20) may be performed simultaneously.

[0076] Next, in step S30, as illustrated in (c) of FIG. 8, in a state in which 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 to each other inside the cylindrical body 10, a third step is performed in which the die 40 presses the cylindrical body 10 from the outside toward the inside (see the black arrow). The die 40 has a fourth molding surface 40a, which is a surface corresponding to the valve seat surface 11, the flow straightening surface 12, and the adjustment surface (13) (not shown). The first core 31, the second core 32, and the die 40 are arranged so 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 flow straightening surface 12, and the adjustment surface 13 are formed by the peripheral wall of the cylindrical body 10 which is formed so as to protrude inward in the radial direction of the cylindrical body 10. As illustrated in Fig. 1, the valve seat surface 11 is a flat surface having an arc shape rather than an annular shape, the flow straightening surface 12 is a surface connecting the ridge line 11R which is the end of the valve seat surface 11 on the inside in the radial direction of the cylindrical body 10 to the inner peripheral surface of the cylindrical body 10, and the adjustment surface 13 is a surface connecting both ends 11E of the valve seat surface 11 in the circumferential direction of the cylindrical body 10, both ends of the flow straightening surface in the circumferential direction of the cylindrical body 10, and the inner peripheral surface of the cylindrical body.

[0078] Once the desired valve seat surface 11, straightening surface 12 and adjustment surface 13 are formed by the peripheral wall of the cylindrical body 10 which is molded so as to protrude radially inward of the cylindrical body 10 as described above, the crushing die 40 is separated from the cylindrical body 10 and the first core 31 and the second core 32 are pulled out from the ends of the cylindrical body, completing the manufacture of the valve body of the present invention.

[0079] Therefore, in the fifth molding method, the first surface 31t and the second surface 32t are configured so that the first core 31 can be extracted from one end of the cylindrical body 10 and the second core 32 can be extracted from the other end of the cylindrical body 10 after the third step executed in step S30 is completed. Specifically, the first core 31 and the second core 32 are configured to have a shape that can be obtained by dividing the shape of the internal space of the cylindrical body 10 after the third step into two in the direction of the axis AX of the cylindrical body 10 by a surface including 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 including 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 third step into two and separate them in the direction of the axis AX of the cylindrical body 10.

[0080] 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 well known in the art depending on, for example, the properties (e.g., mechanical strength and hardness) of the material constituting the cylindrical body 10, the thickness of the peripheral wall of the cylindrical body 10, and the shapes and sizes of the valve seat surface 11, the flow straightening surface 12, and the adjustment surface 13 to be formed. Typically, a press machine such as a hydraulic press machine 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 mount portion for attaching the rotating shaft and / or the drive mechanism for rotating the rotating shaft to the valve body of the present invention, a flat seat surface may be formed on the periphery of the shaft hole by, for example, pressing, or the periphery of the shaft hole may be raised by, for example, burring, etc. Such processing of the mount portion may be performed before the fifth molding method or after the fifth molding 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 processing of the cylindrical body using the first and second cores and the crushing die. Therefore, compared with the case where a similar structure is formed by cutting processing as in the above-mentioned conventional technology, for example, the processing time is short, the material loss is small, and the manufacturing cost can be reduced. That is, according to the fifth embodiment of the present invention, a valve body that can use a flat valve body and achieve a smooth flow of fluid can be easily manufactured. Also, in the fifth embodiment of the present invention, since the position and shape of the molded portion are uniquely determined by the first and second cores and the crushing die, a valve seat surface having an accurate position, shape, and angle can be formed. Therefore, the molding method for the valve body according to the fifth embodiment of the present invention (fifth molding method) is particularly useful in the case where, for example, a plurality of valve seat surfaces having accurate relative positions, shapes, and mutual parallelism are to be formed.

[0083] Sixth Embodiment Hereinafter, a valve body molding method according to a sixth embodiment of the present invention (hereinafter, may be referred to as the "sixth molding method") will be described 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 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 above-mentioned first embodiment, 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 straightening surface when the valve is opened can be more reliably reduced, and the effect of achieving a smooth flow of the fluid can be further enhanced. The sixth molding method is a molding method for a second valve body having such a configuration and capable of achieving the effects.

[0085] <composition> That is, the sixth molding method is the fifth molding method described above, which is a molding method for a valve body, characterized in that the requirements listed below are satisfied in a cross section taken along a plane including the axis of the cylindrical body. A first angle that is an angle formed between the first molding surface of the first core and an outer circumferential surface adjacent to the base end side of the first molding surface on the inside in the radial direction of the cylindrical body is 90 degrees or more. A second angle, which is an angle formed by the second molding surface of the second core and an outer circumferential surface adjacent to the base end side of the second molding surface on the inside in the radial direction of the cylindrical body, is larger than the first angle.

[0086] Fig. 9 is a schematic diagram showing one example of the configuration of the first core and the second core used in the sixth molding method, and corresponds to Fig. 8(b) referred to in the explanation of the fifth molding method. More specifically, Fig. 9 is an enlarged cross-sectional view of the vicinity of the adjacent first molding surface 31a of the first core and the second molding surface 32a of the second core in a state in which 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 to each other inside the cylindrical body 10, as described in the explanation of the fifth molding method.

[0087] 9, in the first core 31 used in the sixth molding method, a first angle θ1, which is an angle between a first molding surface 31a, which is a surface corresponding to the valve seat surface 11, and an adjacent outer circumferential surface at the base end side (upper side in the drawing) of the first molding surface 31a, on the inside in the radial direction of the cylindrical body 10 (right side in the drawing), is 90 degrees or more. Also, in the second core 32 used in the sixth molding method, a second angle θ2, which is an angle between a second molding surface 32b, which is a surface corresponding to the flow straightening surface 12, and an adjacent outer circumferential surface at the base end side of the second molding surface 32b, on the inside in the radial direction of the cylindrical body 10, is larger than the first angle θ1 (θ1<θ2).

[0088] Although not shown, as described in the explanation of the fifth molding method, in the third step, a die (not shown) having a fourth molding surface which is a surface corresponding to the valve seat surface, the straightening surface, and the adjustment surface to be molded, and a first core 31 and a second core 32 are arranged so that the peripheral wall of the cylindrical body 10 is sandwiched between the first molding surface 31a, the second molding surface 32b, the third molding surface (not shown), and the fourth molding surface (not shown). That is, the fourth molding surface of the die is formed so as to have a shape corresponding to the first molding surface 31a and the second molding surface 32b and the third molding surface (not shown) exemplified in Fig. 9. Therefore, according to the sixth molding method, a second valve body having a valve seat angle of 90 degrees or more and a straightening angle larger 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 an angle between the first molding surface of the first core and the outer peripheral surface adjacent to the base end side of the first molding surface, on the inside in the radial direction of the cylindrical body, is 90 degrees or more. Also, the second angle, which is an angle between the second molding surface of the second core and the outer peripheral surface adjacent to the base end side of the second molding surface, on the inside in the radial direction of the cylindrical body, 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, 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 can be more reliably reduced, and the effect of achieving a smooth flow of the fluid can be further enhanced.

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

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

[0092] The seventh molding method has the same configuration as the fifth molding method described with reference to the flowchart of Fig. 7, except that the core and the die are configured so that the valve seat surfaces are formed on the inner peripheral surfaces of the cylindrical bodies on both sides of the rotation axis of the butterfly valve body. Therefore, since the flow of each step included in the seventh molding method is the same as the flow chart exemplified in Fig. 7, please refer to the fifth molding method described with reference to the flowchart of Fig. 7 for the flow of each step included in the seventh molding method.

[0093] Meanwhile, please refer to Fig. 10 for changes in the shape and positional relationship of each member during the process of molding the third valve body from the cylindrical state 10 by the seventh molding method. Fig. 10 is a schematic cross-sectional view illustrating the shape and positional relationship of each member upon completion of the first to third steps included in the seventh molding method. The fourth molding method will be described below with reference to Figs. 7 and 10. In the following description, for the purpose of making the present embodiment easier to understand, parts that are not shown are also denoted by reference characters in parentheses.

[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 exemplified in FIG.

[0095] First, in step S10, as shown in (a) of Fig. 10, 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 flow straightening surface 12b, and a seventh molding surface (33c) corresponding to the 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 shown in (b) of Fig. 10, 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 flow straightening surface 11b, and a tenth molding surface (34c) corresponding to the first adjustment surface (13a) (not shown) is inserted from the other end of the cylindrical body 10 (see the arrow hatched with diagonal lines).

[0096] In the example shown in Fig. 7 and Fig. 10, the third core 33 is inserted from the upper end of the cylindrical body 10 facing Fig. 10 in the first step (step S10), and the fourth core 33 is inserted from the lower end of the cylindrical body 10 facing Fig. 10 in the next second step (step S20). However, on the contrary, the third core 33 may be inserted from the lower end of the cylindrical body 10 facing Fig. 10 in the first step (step S10), and the fourth core 34 may be inserted from the upper end of the cylindrical body 10 facing Fig. 10 in the next second step (step S20). Also, the second step (step S20) may be performed before performing the first step (step S10). Furthermore, the first step (step S10) and the second step (step S20) may be performed simultaneously.

[0097] Next, in step S30, as illustrated in (c) of Figure 10, 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 abutting and engaging with each other inside the cylindrical body 10, the third step is executed in which the first crushing die 41 and the second crushing die 42 are pressed from the outside to the inside of the cylindrical body 10 (see the black arrows).

[0098] The first crushing die 41 has an eleventh molding surface 41a which is a surface corresponding to the first valve seat surface 11a, the first flow straightening surface 12a, and the first adjusting surface (13a) not shown. The third core 33, 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, and 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 twelfth molding surface 42a which is a surface corresponding to the second valve seat surface 11b, the second flow straightening surface 12b, and the second adjustment surface (13b) not shown. The third core 33, 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 eighth molding surface 34a, the sixth molding surface 33b, and the seventh molding surface (33c) not shown, and the twelfth molding surface 42a.

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

[0101] FIG. 11 is a schematic diagram showing an example of a process performed after the third process is completed as described above. When the first valve seat surface 11a, the first flow straightening surface 12a, and the first adjustment surface 13a, and the second valve seat surface 11b, the second flow straightening surface 12b, and the 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 (see the black arrows) as illustrated in FIG. 11(d). Thereafter, the third core 33 and the fourth core 34 are pulled out from the end of the cylindrical body 10 (see the white arrows) as illustrated in FIG. 11(e). As a result, as illustrated in FIG. 11(f), a third valve body 103 is obtained in which the desired valve seat surface, flow straightening surface, and adjustment surface are integrally formed on the inner circumferential surface of the cylindrical body on both sides of the rotation axis of the butterfly valve body. In addition, the process illustrated in Fig. 11(d) and the process illustrated in Fig. 11(e) may be performed in the reverse order to that described above, or the process illustrated in Fig. 11(d) and the process illustrated in Fig. 11(e) may be performed simultaneously.

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

[0103] Furthermore, as described in the explanation of the first to third valve bodies, in a mount portion for attaching a rotating shaft and / or a drive mechanism for rotating the rotating shaft to the valve body of the present invention, a flat seat surface may be formed on the periphery of the shaft hole by, for example, pressing, or the periphery of the shaft hole may be raised by, for example, burring, etc. Such processing of the mount portion may be performed before the seventh molding method or after the seventh molding method.

[0104] <effect> As described above, in the seventh embodiment of the present invention, the intended valve seat surface, flow straightening surface, and adjustment surface are integrally formed on the inner circumferential surface of the cylindrical body on both sides of the rotation axis of the butterfly valve body by plastic processing of the cylindrical body using the third and fourth cores 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 a smooth flow of fluid, and it is also possible to further improve the sealing performance when the valve is closed.

[0105] Eighth Embodiment Hereinafter, a molding method for a valve body according to an eighth embodiment of the present invention (hereinafter, may be referred to as "the eighth molding method") will be described with reference to the drawings.

[0106] As described in the explanation of the fourth valve body, in order to ensure the maximum flow rate of the fluid in the butterfly valve, it is preferable that the projected area of ​​the butterfly valve body when fully open is as small as possible in a vertical projection onto the direction of fluid flow. From this viewpoint, it is preferable that the first abutment surface that abuts against the first valve seat surface of the butterfly valve body and the second abutment surface that abuts against 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 capable of achieving such an effect.

[0107] <composition> That is, the eighth molding method is the seventh molding method described above, and is a molding method for a valve body characterized in that the following requirements D to F are satisfied in a state in which 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 to each other inside the cylindrical body 10. In the following explanation, please refer to Fig. 12 for the third core and the fourth core, and Fig. 5 for the butterfly valve body. Fig. 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 FIG. 12, the first molding plane PF1, which is a plane including the fifth molding surface 33a of the third core 33, and the second molding plane PF2, which is a plane including the eighth molding surface 34a of the fourth core 34, are parallel to each other and are separated by a predetermined third distance D3. As described above, from the viewpoint of ensuring the maximum flow rate of the fluid in the butterfly valve as large as possible, it is preferable that the first abutment surface, which is a surface that abuts against the first valve seat surface of the butterfly valve body, and the second abutment surface, which is a surface that abuts against 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 the 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 must satisfy requirement D.

[0109] The first valve seat surface 11a and the second valve seat surface 11b formed in the fourth valve body 104 by the fifth molding surface 33a of the third core 33 and the eighth molding surface 34a of the fourth core 34, which satisfy the requirement D, satisfy the requirement A described in the description of the fourth valve body. That is, as illustrated in Fig. 5, the first valve seat plane PS1, which is a plane including the first valve seat surface 11a, and the second valve seat plane PS2, which is a plane including the second valve seat surface 11b, are parallel to each other and are separated by a first distance D1, which is a predetermined distance. That is, the third distance D3, which is the distance between the first molding plane PF1 and the second molding 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 practice, the first distance D1 and the third distance D3 may not strictly match. For example, if a slight gap occurs between the fifth molding surface 33a of the third core 33 and the inner peripheral surface of the cylindrical body 10 in the above-mentioned third step, and a slight gap occurs between the eighth molding surface 34a of the fourth core 34 and the inner peripheral surface of the cylindrical body 10, the first distance D1 becomes slightly larger than the third distance D3 by an amount corresponding to these gaps (D1>D3).

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

[0112] The requirement F is that the third distance D3 is equal to the second distance D2. As described above, the third distance D3 between the first molding plane PF1 and the second molding plane PF2 is reflected, and the first distance D1 between the first valve seat plane PS1 and the second valve seat plane PS2 is equal to the third distance (D1=D3). Therefore, when the requirement F is satisfied and the third distance D3 is equal to the second distance D2 between the first abutment plane PC1 and the second abutment plane PC2 of the butterfly valve body 20 (D2=D3), the first distance D1 is equal to the second distance (D1=D2).

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

[0114] In the above, for the purpose of explaining the present invention, several embodiments having specific configurations have been described with reference to the attached drawings. However, the scope of the present invention should not be construed as being limited to these exemplary embodiments, and it goes without saying that appropriate modifications can be made within the scope of the claims and the matters described in the specification. For example, the shape of the cross section (transverse section) perpendicular to the axis of the valve body exemplified in this application is circular, but the shape of the cross section of the valve body is not limited to circular, and may be an irregular cross section such as an ellipse or an oval, as long as the function as a butterfly valve is not impaired. However, in this case, it is naturally necessary that the shape of the butterfly valve body also corresponds to the shape of the cross section of the valve body. In addition, the attached drawings of this application show an example of a valve body having an enlarged diameter portion formed at the end for the purpose of connecting to an adjacent pipe, but the valve body may be configured by integrally forming a valve seat surface, etc., on the pipe 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…Ridgeline 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...Axle hole AX…Axis 14S…Seat 20...Butterfly valve body 21...Pivot shaft 22a...first contact surface 22b…Second contact surface PC1…1st connection plane PC2…Second connection plane D2…2nd distance 31…Neutron 1 31a…1st molding surface 31t…Side 1 θ1…1st angle 32…Neutron 2 32b…Second forming surface 32c…3rd forming surface 32t…Side 2 θ2…Second angle 33…Neutron 3 33a…Fifth forming surface 33b…6th forming surface 33c…7th forming surface 33t…Page 3 PF1…1st forming plane 34…4th Neutron 34a…8th forming surface 34b…9th forming surface 34c…10th forming surface 34t…Side 4 PF2…2nd forming plane D3…3rd distance 40…collapse type 40a…4th 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 constituting a butterfly valve, the valve body being configured by rotatably housing a butterfly valve element inside a cylindrical body and integrally forming a valve seat surface protruding radially inwardly of the cylindrical body, the valve seat surface is formed by a peripheral wall of the cylindrical body that is formed so as to protrude toward the inside in the radial direction of the cylindrical body, and is a plane having an arc shape rather than an annular shape, a straightening surface that connects a ridge line that is an end of the valve seat surface on the inside in the radial direction of the cylindrical body and an inner circumferential surface of the cylindrical body is formed on the downstream side of the valve seat surface in a valve closing direction that is a rotation direction of the butterfly valve element when the valve is closed, 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. A valve body comprising:

2. 2. The valve body of claim 1, In a cross section taken along a plane including the axis of the cylindrical body, a valve seat angle, which is an angle between the valve seat surface and an 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; a straightening angle, which is an angle between the straightening surface and an inner circumferential surface of the cylindrical body adjacent to the straightening surface on the inside in the radial direction of the cylindrical body, is larger than the valve seat angle; A valve body comprising:

3. 3. The valve body according to claim 1 or 2, The valve seat surface, the straightening surface, and the adjustment surface are formed on the inner circumferential surface of the cylindrical body on both sides of the rotation axis of the butterfly valve body as a first valve seat surface, a first straightening surface, and a first adjustment surface, and a second valve seat surface, a second straightening surface, and a second adjustment surface, respectively. A valve body comprising:

4. 4. The valve body according to claim 3, a first valve seat plane including the first valve seat surface and a second valve seat plane including the second valve seat surface are parallel to each other and are spaced apart from each other by a first distance, which is a predetermined distance; a first abutment plane including a first abutment surface which is a plane that seats on the first valve seat surface when the butterfly valve body is closed, and a second abutment plane including a second abutment surface which is a plane that seats on the second valve seat surface when the butterfly valve body is closed, the first abutment plane and the second abutment plane are parallel to each other and are spaced apart by a second distance which is a predetermined distance, the first distance is equal to the second distance; A valve body comprising:

5. 2. A method for molding a valve body according to claim 1, comprising the steps of: a first step of inserting a first core having a first molding surface corresponding to the valve seat surface from one end of the cylindrical body; a second step of inserting a second core having a second molding surface corresponding to the flow straightening surface and a third molding surface corresponding to the adjustment surface from the other end of the cylindrical body; and a third step of pressing a crushing die having a fourth molding surface corresponding to the valve seat surface, the flow straightening surface, and the adjustment surface from the outside to the inside of the cylindrical body so as to sandwich a peripheral wall of the cylindrical body between the first molding surface, the second molding surface, the third molding surface, and the fourth molding surface, while a first surface which is a tip surface of the first core and a second surface which is a tip surface of the second core are in contact with and fitted to each other inside the cylindrical body; Including, the first surface and the second surface are configured such that, after the third step is completed, the first core can be extracted from the one end of the cylindrical body and the second core can be extracted from the other end of the cylindrical body. A method for molding a valve body.

6. A method for molding a valve body according to claim 5, comprising the steps of: In a cross section taken along a plane including the axis of the cylindrical body, a first angle formed between the first molding surface of the first core and an outer circumferential surface adjacent to the base end side of the first molding surface on an inner side in a radial direction of the cylindrical body is 90 degrees or more; a second angle, which is an angle formed between the second molding surface of the second core and an outer peripheral surface adjacent to the base end side of the second molding surface on an inner side in a radial direction of the cylindrical body, is larger than the first angle; A method for molding a valve body.

7. A method for molding a valve body according to claim 3, comprising the steps of: a first step of inserting a third core, the third core having a fifth molding surface corresponding to the first valve seat surface, a sixth molding surface corresponding to the second flow straightening surface, and a seventh molding surface corresponding to the second adjustment surface, from one end of the cylindrical body; a second step of inserting a fourth core, the fourth core having an eighth molding surface corresponding to the second valve seat surface, a ninth molding surface corresponding to the first flow straightening surface, and a tenth molding surface corresponding to the first adjustment surface, from the other end of the cylindrical body; and a third step of pressing a first collapsing die having an eleventh molding surface which is a surface corresponding to the first valve seat surface, the second flow straightening surface, and the second adjusting surface from the outside toward the inside of the cylindrical body so as to sandwich a 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 pressing a second collapsing die having a twelfth molding surface which is a surface corresponding to the second valve seat surface, the first flow straightening surface, and the first adjusting surface from the outside toward the inside of the cylindrical body so as to sandwich a peripheral wall of the cylindrical body between the eighth molding surface, the ninth molding surface, the tenth molding surface, and the twelfth molding surface; Including, the third surface and the fourth surface are configured such that, after the third step is completed, the third core can be extracted from the one end of the cylindrical body and the fourth core can be extracted from the other end of the cylindrical body. A method for molding a valve body.

8. A method for molding a valve body according to claim 7, comprising the steps of: In a state in which a third surface which is a tip surface of the third core and a fourth surface which is a tip surface of the fourth core abut against and fit to each other inside the cylindrical body, a first molding plane which is a plane including the fifth molding surface of the third core and a second molding plane which is a plane including the eighth molding surface of the fourth core are parallel to each other and are spaced apart from each other by a third distance which is a predetermined distance; a first abutment plane including a first abutment surface which is a plane that seats on the first valve seat surface when the butterfly valve body is closed, and a second abutment plane including a second abutment surface which is a plane that seats on the second valve seat surface when the butterfly valve body is closed, the first abutment plane and the second abutment plane are parallel to each other and are spaced apart by a second distance which is a predetermined distance, the third distance is equal to the second distance; A method for molding a valve body.

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