Butterfly valve and method for manufacturing a butterfly valve

Abstract

To provide a butterfly valve capable of executing rapid product supply, and eliminating the possibility of foreign matter entering a fluid.SOLUTION: A butterfly valve 1 comprises a valve box 2 and a valve body 3. The valve box 2 is connected to a pipe conduit such as a water supply and sewerage pipe, and has an in-valve box flow path 7 through which water and sewage flow. The valve body 3 for opening and closing the in-valve box flow path 7 has a valve body base part 8, and a connection member 9 that is connected to an edge part of the valve body base part 8. The connection member 9 has: a valve body valve seat 11 that is brought into contact with the valve box 2 when the valve body 3 closes the in-valve box flow path 7; a shaft part 12 connected to the valve body valve seat 11; and protrusion parts 13, 14 protruding from the shaft part 12. The edge part of the valve body base part 8 has a shaft part storage groove 18 that stores the shaft part 12, and protrusion part storage grooves 19, 20 that store the protrusion parts 13, 14. The connection member 9 is crimped to the edge part of the valve body base part 8. The shaft part 12 is stored in the shaft part storage groove 18. The protrusion parts 13, 14 are stored in the protrusion part storage grooves 19, 20.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present invention relates to a butterfly valve and a method for manufacturing a butterfly valve. 【Background Art】 【0002】 Conventionally, a butterfly valve installed in piping used for water supply and drainage pipes, water channels in power facilities, and water channels for river water has been known (see, for example, Patent Document 1). The butterfly valve of Patent Document 1 includes a valve box connected to a pipe such as a water supply and drainage pipe, and a disk-shaped valve body disposed inside the valve box. The valve body rotates inside the valve box to open and close the flow path of fluids such as water supply and drainage inside the valve box. When the valve body closes the flow path of the fluid inside the valve box, the valve body valve seat, which is the edge of the valve body, adheres closely to the valve box valve seat provided annularly inside the valve box. 【0003】 The valve body is formed of metal, for example, cast iron. The edge of the formed valve body is subjected to cutting to form the valve body valve seat. The valve body valve seat is subjected to surface treatment, for example, plating or painting, to suppress the generation of rust. 【Prior Art Documents】 [[ID=二十]] 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2000-230645 [[ID=三十]] 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, when outsourcing the surface treatment to a specialized contractor, it may take more than one month until the valve body with the surface treatment is delivered. Further, when a butterfly valve with the surface treatment applied to a part of the valve body is installed in a pipeline, a thin film such as a plating film or a coating film formed on a part of the valve body may peel off from the valve body into the fluid. Therefore, there is a problem that it is impossible to execute rapid product supply and eliminate the possibility of foreign matter mixing into the fluid. 【0006】 The object of the present invention is to provide a butterfly valve and a method for manufacturing a butterfly valve that enables rapid product supply and eliminates the possibility of foreign matter being mixed into the fluid. [Means for solving the problem] 【0007】 (1) A butterfly valve according to one aspect of the present invention is a butterfly valve installed in a pipeline through which a fluid flows, A valve body connected to the aforementioned pipeline and having a fluid passage, A valve body that rotates inside the valve casing to open and close the flow path, A connecting member connected to the edge of the valve body, Equipped with, The connecting member has a valve seat that abuts against the valve body when the valve body is closing the flow path, and a projection that protrudes toward the interior of the valve body. The edge of the valve body has a projection-accommodating groove for accommodating the projection. This resolved the above issues. 【0008】 (2) The present invention is The connecting member has a shaft portion interposed between the valve body seat and the projection, The valve body seat is connected to one end of the shaft, and the projection protrudes from the other end of the shaft. The projection extends from the shaft towards the center of the valve body's contour when viewed in the direction of the flow path while the flow path is closed. The edge of the valve body has a shaft housing groove for housing the shaft portion. It is possible. 【0009】 (3) The present invention is A connection strengthening agent is interposed between the connecting member and the edge of the valve body. It is possible. 【0010】 (4) The present invention is The aforementioned projection is housed in the projection housing groove and is inclined with respect to the shaft portion. It is possible. 【0011】 (5) The present invention where the shaft portion has a plurality of the protrusions, an edge portion of the valve body has a plurality of the protrusion receiving grooves, and each of the protrusions corresponds to each of the protrusion receiving grooves. is possible. 【0012】 (6) The present invention where the connecting member has the protrusion at an end portion, and the protrusion protrudes from the end portion toward the center in the thickness direction of the valve body. is possible. 【0013】 (7) The present invention where a connection strengthening agent is interposed between the connecting member and an edge portion of the valve body. is possible. 【0014】 (8) The present invention where the valve body valve seat has a plurality of the protrusions, an edge portion of the valve body has a plurality of the protrusion receiving grooves, and each of the protrusions corresponds to each of the protrusion receiving grooves. is possible. 【0015】 (9) The present invention when each of the protrusions is accommodated in the protrusion receiving groove, the valve body is fastened to the connecting member. is possible. 【0016】 (10) A method for manufacturing a butterfly valve according to another aspect of the present invention comprises a valve box that is connected to a pipeline through which a fluid flows and has a flow path of the fluid, a valve body that rotates inside the valve box to open and close the flow path, and a connecting member that is connected to an edge portion of the valve body. The connecting member has a valve body valve seat that abuts against the valve box when the valve body closes the flow path, a shaft portion that is connected to the valve body valve seat, and a protrusion that protrudes from the shaft portion. In a method for manufacturing a butterfly valve, an edge portion of the valve body has a shaft portion receiving groove that accommodates the shaft portion and a protrusion receiving groove that accommodates the protrusion. A pressing step of pressing the connecting member; A deformation step of deforming the protrusion that abuts against the protrusion accommodating groove, and having; The above problems have been solved thereby. 【0017】 (11) A method for manufacturing a butterfly valve according to another aspect of the present invention is, Connected to a pipeline through which a fluid flows, and includes a valve box having a flow path of the fluid, a valve body that rotates inside the valve box to open and close the flow path, and a connecting member connected to an edge of the valve body. The connecting member has a valve body valve seat that abuts against the valve box when the valve body closes the flow path, and a protrusion protruding from the valve body valve seat. In a method for manufacturing a butterfly valve in which an edge of the valve body has a protrusion accommodating groove for accommodating the protrusion, A forming step of forming the valve body valve seat; A pressing step of pressing the connecting member; A deformation step of deforming the protrusion that abuts against the protrusion accommodating groove, and having; The above problems have been solved thereby. 【Effect of the Invention】 【0018】 According to the present invention, it is possible to provide a butterfly valve and a method for manufacturing a butterfly valve that can execute rapid product supply and eliminate the possibility of foreign matter mixing into the fluid. 【Brief Description of the Drawings】 【0019】 [Figure 1] It is a front view of a butterfly valve according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of the valve body along the line II-II in FIG. 1. [Figure 3] It is a view used to explain the connecting member in FIG. 2, and shows a part of the connecting member before being connected to the edge of the valve body base. [Figure 4] It is a view showing a part of the edge of the valve body base to which the connecting member in FIG. 3 is connected. [Figure 5] This figure is used to explain the state after the connecting member in Figure 3 is connected to the edge of the valve body base in Figure 4. [Figure 6] This flowchart shows the procedure for connecting the connecting member in Figure 3 to the edge of the valve body base in Figure 4. [Figure 7] These diagrams are used to explain the intermediate steps in the connection process shown in Figure 6. Figure 7(a) shows how the connecting member is inserted into the shaft housing groove and the projection housing groove in insertion step S1 of Figure 6, and Figure 7(b) shows how the tip of the projection is in contact with the projection housing groove in step S2 of Figure 6. [Figure 8] This is a cross-sectional view of the valve body along the line II-II in Figure 1, and is used to illustrate a modified example of the valve body in Figure 2. [Figure 9] This diagram is used to explain the connecting member in Figure 8, and shows a part of the connecting member before it is connected to the edge of the valve body base. [Figure 10] This figure shows a portion of the edge of the valve body base to which the connecting member shown in Figure 9 is connected. [Figure 11] This figure is used to explain the state after the connecting member in Figure 9 is connected to the edge of the valve body base in Figure 10. [Figure 12] This flowchart shows the procedure for connecting the connecting member in Figure 9 to the edge of the valve body base in Figure 10. [Figure 13] This figure shows the connected member in a curved state during deformation step S5 of the connection process shown in Figure 12. [Figure 14] This figure shows the tip of the projection in contact with the projection housing groove during the connecting member pressing step S7 of the connection process shown in Figure 12. [Modes for carrying out the invention] 【0020】 Hereinafter, embodiments of the butterfly valve and the method for manufacturing the butterfly valve according to the present invention will be described with reference to the drawings. Figure 1 is a front view showing the butterfly valve 1 in this embodiment. 【0021】 The butterfly valve 1 according to this embodiment, as shown in Figure 1, is installed in a pipeline such as a water and sewage pipe and comprises a valve body 2, a valve element 3, a valve stem 4, an operating handle 5, and a reduction gear 6. The valve body 2 is connected to a pipeline such as a water and sewage pipe and has an internal flow path 7 through which fluids such as water and sewage flow. The valve stem 4 passes through the valve element 3, and the valve stem 4 and the valve element 3 are fixed to each other by bolts and nuts (not shown). The valve element 3 rotates inside the valve body 2 with the valve stem 4 as its central axis, opening and closing the internal flow path 7. The reduction gear 6 is connected to the valve stem 4, and the operating handle 5 is also connected to the reduction gear 6. When a user rotates the operating handle 5, the reduction gear 6 increases or decreases the operating load input by the user's rotation operation and outputs it. The valve stem 4 rotates according to the output load output by the reduction gear 6. 【0022】 Figure 2 is a cross-sectional view of the valve body 3 along the line II-II in Figure 1. 【0023】 As shown in Figure 2, the valve body 3 comprises a valve body base 8, a connecting member 9, a fluid contact surface 10, and a valve stem 4. The fluid contact surface 10 surrounds the valve body base 8, and the valve stem 4 penetrates the valve body base 8. When the valve body 3 of the butterfly valve 1 is not closing the flow path 7 inside the valve body, the fluid contacts the fluid contact surface 10 and forms a flow along the fluid contact surface 10. At this time, the fluid contact surface 10 is mainly curved and streamlined without irregularities or corners, so turbulence is unlikely to occur. The connecting member 9 is connected to the edge of the valve body base 8 to form the edge of the valve body 3. The edge of the valve body 3 is the valve seat 11 that abuts against the valve body 2 when the valve body 3 is closing the flow path 7 inside the valve body. Therefore, the connecting member 9 constitutes the valve seat 11. The connecting member 9 can be made of metal, for example, stainless steel. Because the connecting member 9 is made of stainless steel, it can withstand erosion (abrasive corrosion) even if cavitation occurs in the fluid. 【0024】 Figure 3 is a diagram used to explain the connecting member 9 in Figure 2, and shows a part of the connecting member 9 before it is connected to the edge of the valve body base 8. 【0025】 As shown in Figure 3, the connecting member 9 before being connected to the edge of the valve body base 8 comprises a valve seat 11 that abuts against the valve body 2 when the valve body 3 closes the flow path 7 inside the valve body, a columnar shaft portion 12 connected to the valve seat 11, and projections 13 and 14 protruding from the shaft portion 12. The shaft portion 12 is interposed between the valve seat 11 and the projections 13 and 14, the valve seat 11 is connected to one end of the shaft portion 12, and the projections 13 and 14 protrude from the other end of the shaft portion 12. Furthermore, the shaft portion 12 has a central axis O, and the projections 13 and 14 have an outer projection surface 15 located on the extension of the side surface of the shaft portion 12, an inner projection surface 16 located on the side of the central axis O of the shaft portion 12, and a tip portion 17 that contacts the outer projection surface 15 and the inner projection surface 16, and the angle θ formed by the outer projection surface 15, the tip portion 17 and the inner projection surface 16 is an acute angle. 【0026】 The valve body 3, which opens and closes the flow path 7 inside the valve casing, is disc-shaped and has a substantially circular contour. The shaft portion 12 of the connecting member 9, which is arranged along this contour, has a constant dimension in the direction perpendicular to the contour of the valve body 3 (hereinafter referred to as the "thickness direction of the valve body 3"). In other words, the sides of the shaft portion 12 are parallel to each other. The outer surface 15 of the projection is flush with the side surface of the shaft portion 12 before the connecting member 9 is connected to the edge of the valve body base portion 8. In contrast, with the connecting member 9 connected to the edge of the valve body base portion 8, the outer surface 15 of the projection is located outward in the thickness direction of the valve body 3 from the side surface of the shaft portion 12. 【0027】 Figure 4 shows a portion of the edge of the valve body base 8 to which the connecting member 9 in Figure 3 is connected. Figure 5 is used to explain the state after the connecting member in Figure 3 is connected to the edge of the valve body base in Figure 4. 【0028】 As shown in Figure 4, the edge of the valve body base 8 has a shaft housing groove 18 for accommodating the shaft portion 12 of the connecting member 9, and projection housing grooves 19 and 20 for accommodating the projections 13 and 14 of the connecting member 9. The shaft portion 12 is housed in the shaft housing groove 18 without any gaps. The projections 13 and 14 are bent at their boundary with the shaft portion 12 and housed in the projection housing grooves 19 and 20 (Figure 5). Therefore, when the projections 13 and 14 are housed in the projection housing grooves 19 and 20, they are inclined with respect to the shaft portion 12. The projections 13 and 14 are formed extending from the shaft portion 12 toward the interior of the valve body 3. A connection reinforcing agent, such as an adhesive, may be interposed between the edge of the connecting member 9 and the valve body base 8 to reinforce the connection between them. Incidentally, the interior of the valve body 3 is the area enclosed by the contour of the valve body 3 formed by the valve body base 8 and the fluid contact surface 10 before the connecting member 9 and the connecting member 24 described later are connected. Therefore, in this embodiment, the protrusions 13, 14, 25, and 26 of the connecting members 9 and 24, respectively, protrude from the outside to the inside of the contour of the valve body 3, in other words, toward the interior of the valve body 3 (Figures 2 and 8). 【0029】 The projection-receiving grooves 19 and 20 have an outer groove side surface 21 facing the outer surface 15 of the projection, an inner groove side surface 22 facing the inner surface 16 of the projection, and a tip receiving portion 23 where the outer groove side surface 21 and the inner surface 16 of the projection intersect and the tip portions 17 of the projections 13 and 14 are located. The angle φ formed by the outer groove side surface 21, the tip receiving portion 23, and the inner surface 16 of the projection is acute. 【0030】 The angle φ of the projection housing grooves 19 and 20 is preferably 20 to 60 degrees, and the angle θ of the connecting member 9 is preferably smaller than the angle φ of the projection housing grooves 19 and 20 and between 15 and 40 degrees. If the angle θ of the connecting member 9 is less than 15 degrees, the projections 13 and 14 are prone to breakage, and if the angle θ of the connecting member 9 is greater than 40 degrees, excessive load is required to bend the projections 13 and 14, which is undesirable. Furthermore, if the angle φ of the projection housing grooves 19 and 20 is less than 20 degrees, it is difficult to accommodate the projections 13 and 14 of the connecting member 9 in the projection housing grooves 19 and 20, and if the angle φ of the projection housing grooves 19 and 20 is greater than 60 degrees, the connecting member 9 is prone to detaching from the edge of the valve body base 8, which is undesirable. 【0031】 The shaft portion 12 of the connecting member 9 has multiple protrusions, and the edge portion of the valve body 3 has multiple grooves for accommodating the protrusions, and each protrusion is formed to correspond to each groove for accommodating the protrusions. In this embodiment, the connecting member 9 has two protrusions 13 and 14, and the edge portion of the valve body base 8 has two grooves for accommodating the protrusions 19 and 20, with protrusion 13 corresponding to groove 19 and protrusion 14 corresponding to groove 20. When the connecting member 9 is connected to the edge portion of the valve body base 8, the shaft portion 12 is accommodated in the shaft portion accommodating groove 18 without any gaps, and the protrusions 13 and 14 are bent at the boundary with the shaft portion 12 and accommodated in grooves 19 and 20 for accommodating the protrusions (Figure 5). At this time, both protrusions 13 and 14 are bent outward (towards the fluid contact surface 10) in the thickness direction of the valve body 3. 【0032】 Figure 6 is a flowchart illustrating the procedure for connecting the connecting member 9 in Figure 3 to the edge of the valve body base 8 in Figure 4. Figure 7 is used to illustrate the intermediate steps in the connection process in Figure 6. Figure 7(a) shows how the connecting member is inserted into the shaft housing groove and the projection housing groove in insertion step S1 of Figure 6, and Figure 7(b) shows how the tip of the projection is in contact with the projection housing groove in pressing step S2 of Figure 6. 【0033】 The manufacturing method of the butterfly valve in this embodiment, as shown in Figure 6, includes an insertion step S1, a pressing step S2, a projection deformation step S3, and a connecting member crimping step S4. 【0034】 As insertion step S1 shown in Figure 6, the connecting member 9 is inserted into the shaft housing groove 18 and the projection housing grooves 19 and 20. First, in order to reinforce the connection between the connecting member 9 and the edge of the valve body base 8, adhesive is applied to the edge of the valve body base 8, and the shaft portion 12 and projections 13, 14 of the connecting member 9 are inserted toward the shaft portion housing groove 18 and projection portion housing grooves 19, 20 (Figure 7(a)). At this time, with the outer surface 15 of the projection flush with the side surface of the shaft 12, the shaft 12 and the projections 13 and 14 are inserted into the shaft housing groove 18. 【0035】 As pressing step S2 shown in Figure 6, the valve body seat 11 is pressed. When the tips 17 of the projections 13 and 14 come into contact with the projection housing grooves 19 and 20, the valve seat 11 is pressed from the shaft housing groove 18 toward the projection housing grooves 19 and 20, that is, the valve seat 11 is pressed toward the center from the edge of the valve body 3 (Figure 7(b)). 【0036】 As step S3 of the projection deformation shown in Figure 6, the projections 13 and 14 are deformed. When the valve body seat 11 is pressed, the tips 17 of the projections 13 and 14 move along the projection housing grooves 19 and 20 to the tip receiving portion 23, and the projections 13 and 14 bend at the boundary with the shaft portion 12. The projections 13 and 14 bend outward in the thickness direction of the valve body 3. That is, the outer surface 15 of the projections bends toward the fluid contact surface 10, which is outward in the thickness direction of the valve body 3, compared to the side surface of the shaft portion 12. 【0037】 As shown in Figure 6, the connecting member crimping step S4 involves crimping the connecting member 9 to the edge of the valve body base 8. When the tips 17 of the protrusions 13 and 14 reach the tip receiving portion 23, the connecting member 9 is pressed against the edge of the valve body base 8 (Figure 5). This completes the process. 【0038】 In addition, during the connecting member crimping step S4, the tips 17 of the projections 13 and 14 may be crushed by the tip receiving portion 23 depending on the size of the projections 13 and 14 and the projection housing grooves 19 and 20. In this case, the connecting member 9 is firmly joined to the edge of the valve body base 8, so it is possible to prevent the connecting member 9 from detaching from the edge of the valve body base 8. 【0039】 The connecting member 9 is pressed against the edge of the valve body base 8, forming the valve seat 11 on the valve body 3. The valve stem 4 passes through the valve body 2 and connects to the valve casing 2. Next, the reduction gear 6 and the operating handle 5 are connected to the valve casing 2 to complete the butterfly valve 1. This completes the manufacturing method of the butterfly valve. 【0040】 In the connection process shown in Figure 6, the connecting member 9 connected to the edge of the valve body base 8 has a valve seat 11 that abuts against the valve body 2 when the valve body 3 closes the flow path 7 inside the valve body, a shaft portion 12 connected to the valve seat 11, and projections 13 and 14 protruding from the shaft portion 12. The edge of the valve body base 8 has a shaft portion housing groove 18 for housing the shaft portion 12 and projection portion housing grooves 19 and 20 for housing the projections 13 and 14. When the connecting member 9 is inserted into the shaft portion housing groove 18 and the projection portion housing grooves 19 and 20 (insertion step S1), and the tip portions 17 of the projections 13 and 14 abut against the projection portion housing grooves 19 and 20, the valve seat 11 is pressed from the shaft portion housing groove 18 toward the projection portion housing grooves 19 and 20 (pressing step S2). As a result, the tip portions 17 of the projections 13 and 14 move along the projection housing grooves 19 and 20 to the tip receiving portion 23, and the projections 13 and 14 bend at the boundary with the shaft portion 12 (projection deformation step S3), and when the tip portions 17 of the projections 13 and 14 reach the tip receiving portion 23, the connecting member 9 is pressed against the edge of the valve body base portion 8 (connecting member pressing step S4). 【0041】 In other words, the shaft portion 12 is fitted into the shaft portion housing groove 18, the projections 13 and 14 deform along the projection housing grooves 19 and 20, and the connecting member 9 is fixed to the edge of the valve body 3, so that the valve body seat 11 is formed on the edge of the valve body 3 of the butterfly valve 1. Therefore, since there is no need to apply surface treatment to the valve body seat 11 of the butterfly valve 1, the time required to manufacture the butterfly valve 1 is shortened, and since the valve body seat 11 of the butterfly valve 1 is not surface treated, there is no risk of the thin film formed by surface treatment peeling off from the valve body 3 into the fluid, thereby enabling rapid product supply and eliminating the possibility of foreign matter mixing into the fluid. 【0042】 Next, a modified example of this embodiment will be described. 【0043】 Figure 8 is a cross-sectional view of the valve body 3 along the line II-II in Figure 1, and is used to illustrate a modified example of the valve body 3 shown in Figure 2. 【0044】 In this modified example, as shown in Figure 8, the valve body 3 comprises a valve body base 8, a connecting member 24, a fluid contact surface 10, and a valve stem 4. The fluid contact surface 10 surrounds the valve body base 8, and the valve stem 4 penetrates the valve body base 8. The connecting member 24 is connected to the edge of the valve body base 8 to form the edge of the valve body 3. The edge of the valve body 3 is the valve seat 33 that abuts against the valve casing 2 when the valve body 3 is closing the flow path 7 inside the valve casing. Therefore, the connecting member 24 constitutes the valve seat 33. The connecting member 24 can be made of metal, for example, stainless steel. 【0045】 Figure 9 is a diagram used to illustrate the connecting member 24 in Figure 8, and shows a part of the connecting member 24 before it is connected to the edge of the valve body base 8. 【0046】 As shown in Figure 9, the connecting member 24 before being connected to the edge of the valve body base 8 is a long plate and comprises a base and projections 25 and 26 protruding from both ends along the longitudinal direction of the base. The projections 25 and 26 have an outer surface 27 located on the extension of the side surface along the longitudinal direction of the connecting member 24, an inner surface 28 located on the side of the central axis P along the longitudinal direction of the connecting member 24, and a tip 29 that contacts the outer surface 27 and the inner surface 28. The angle λ formed by the outer surface 27, the tip 29, and the inner surface 28 is acute. The connecting member 24, before being connected to the edge of the valve body base 8, has uniform dimensions in the thickness direction (direction of arrow L in Figure 9), except for the projections 25 and 26. The projections 25 and 26 protrude in the thickness direction of the connecting member 24 before being connected to the edge of the valve body base 8. 【0047】 Figure 10 shows a portion of the edge of the valve body base 8 to which the connecting member 24 in Figure 9 is connected. Figure 11 is used to explain the state after the connecting member in Figure 9 is connected to the edge of the valve body base in Figure 10. 【0048】 In this modified example, the edge of the valve body base 8 includes a support portion 30 that supports the connecting member 24 and projection accommodating grooves 31 and 32 that accommodate projections 25 and 26 on the connecting member 24, as shown in Figures 10 and 11, and the support portion 30 has a curved surface 30a. In the connecting member 24 connected to the edge of the valve body base 8, the connecting member 24 is curved along the curved surface 30a of the support portion 30, and the curved connecting member 24 constitutes the valve body seat 33 that abuts against the valve seat of the valve body when the valve body 3 is closing the flow path 7 inside the valve body. 【0049】 In the connecting member 24 connected to the edge of the valve body base 8, the projections 25 and 26 are bent at the boundary with the base of the connecting member 24 and housed in projection housing grooves 31 and 32. The projections 25 and 26 protrude from both ends along the longitudinal direction of the connecting member 24 toward the center in the thickness direction of the valve body 3. A connection reinforcing agent, such as an adhesive, may be interposed between the connecting member 24 and the edge of the valve body base 8 to reinforce the connection between them. 【0050】 Before the connecting member 24 is connected to the edge of the valve body base 8, the outer surface 27 of the projection is flush with the side surface of the long plate connecting member 24 and coincides with the thickness direction of the connecting member 24. In contrast, when the connecting member 24 is connected to the edge of the valve body base 8, the outer surface 27 of the projection is inclined in a direction that is towards the center of the valve body 3 in the thickness direction and toward the center of the valve body 3, more so than the side surface of the connecting member 24. 【0051】 The projection-receiving grooves 31 and 32 have an outer groove side surface 34 facing the outer surface 27 of the projection, an inner groove side surface 35 facing the inner surface 28 of the projection, and a tip receiving portion 36 where the outer groove side surface 34 and the inner groove side surface 35 intersect and the tip portions 29 of the projections 25 and 26 are located, and the angle ε formed by the outer groove side surface 34, the tip receiving portion 36 and the inner groove side surface 35 is acute. 【0052】 The angle ε of the projection housing grooves 31 and 32 is preferably 20 to 60 degrees, and the angle λ of the connecting member 24 is preferably smaller than the acute angle of the projection housing grooves 31 and 32 and between 15 and 40 degrees. If the angle λ of the connecting member 24 is less than 15 degrees, the projections 25 and 26 are prone to breakage, and if the angle λ of the connecting member 24 is greater than 40 degrees, excessive load is required to bend the projections 25 and 26, which is undesirable. Furthermore, if the acute angle of the projection housing grooves 31 and 32 is less than 20 degrees, it is difficult to accommodate the projections 25 and 26 of the connecting member 24 in the projection housing grooves 31 and 32, and if the acute angle of the projection housing grooves 31 and 32 is greater than 60 degrees, the connecting member 24 is prone to detaching from the edge of the valve body base 8, which is undesirable. 【0053】 The connecting member 24 has multiple protrusions, and the edge of the valve body 3 has multiple grooves for accommodating the protrusions, with each protrusion corresponding to each groove. In a modified example of this embodiment, the connecting member 24 has two protrusions 25 and 26, and the edge of the valve body base 8 has two grooves for accommodating the protrusions 31 and 32, with protrusion 25 corresponding to groove 31 and protrusion 26 corresponding to groove 32. When the connecting member 24 is connected to the edge of the valve body base 8 along the curved surface 30a of the support portion 30, the protrusions 25 and 26 bend outward in the width direction of the connecting member 24 at the boundary with the base of the connecting member 24 and are accommodated in the grooves 31 and 32, and the connecting member 24 is tightly fitted to the valve body 3. 【0054】 Figure 12 is a flowchart showing the procedure for connecting the connecting member 24 in Figure 9 to the edge of the valve body base 8 in Figure 10. Figure 13 shows the state in which the connecting member is curved in deformation step S5 of the connection process in Figure 12. Figure 14 shows the state in which the tip of the projection is in contact with the projection housing groove in the connecting member pressing step S7 of the connection process in Figure 12. 【0055】 As shown in Figure 11, a modified example of this embodiment of the method for manufacturing a butterfly valve includes a forming step S5, a projection insertion step S6, a connecting member pressing step S7, a projection deformation step S8, and a connecting member crimping step S9. 【0056】 As deformation step S5 shown in Figure 12, the connecting member 24 is curved so that the projections 25 and 26 face each other, as shown in Figure 13. First, in order to reinforce the connection between the connecting member 24 and the edge of the valve body base 8, adhesive is applied to the edge of the valve body base 8, causing the base of the connecting member 24 to curve along the curved surface of the support portion 30 at the edge of the valve body base 8, thereby forming the valve seat 33. 【0057】 Next, in the projection insertion step S6 shown in Figure 12, the projections 25 and 26 of the connecting member 24 are inserted into the projection housing grooves 31 and 32, respectively. 【0058】 Furthermore, as shown in Figure 12, the connecting member 24 is pressed as a connecting member pressing step S7. Then, as shown in Figure 14, the projections 25 and 26 inserted into the projection housing grooves 31 and 32 have their tips 29 come into contact with the projection housing grooves 31 and 32. At this time, both ends of the connecting member 24 along its longitudinal direction are pressed. 【0059】 Next, as shown in Figure 12, the projections 25 and 26 deform in step S8. As both ends of the connecting member 24 are pressed along the longitudinal direction, the tip portions 29 of the projections 25 and 26 move along the projection housing grooves 31 and 32 to the tip receiving portion 36, and the boundary between the projections 25 and 26 and the base of the connecting member 24 bends. 【0060】 Furthermore, as shown in Figure 12, the connecting member 24 is crimped to the edge of the valve body base 8 as a connecting member crimping step S9. When the tip portions 29 of the projections 25 and 26 reach the tip receiving portion 36, the connecting member 24 is pressed against the edge of the valve body base portion 8. 【0061】 In the connecting member crimping step S9, depending on the size of the projections 25 and 26 and the projection housing grooves 31 and 32, the tip portions 29 of the projections 25 and 26 may be crushed by the tip receiving portion 36. In this case, the connecting member 24 is firmly joined to the edge of the valve body base 8, so it is possible to prevent the connecting member 24 from detaching from the edge of the valve body base 8. The connecting member 24 is pressed against the edge of the valve body base 8, forming the valve seat 33 on the valve body 3, which is then connected to the valve casing 2 by the valve stem 4 passing through it. Next, the reduction gear 6 and the operating handle 5 are connected to the valve casing 2 to complete the butterfly valve 1 (method of manufacturing a butterfly valve). 【0062】 According to the connection process in Figure 12, similar to the connection process in Figure 6, the protrusions 25 and 26 deform along the protrusion housing grooves 31 and 32, and the connecting member 24 is fixed to the edge of the valve body 3. As a result, a valve seat 33 is formed on the edge of the valve body 3 of the butterfly valve 1, thereby achieving the same effect as the connection process in Figure 6. 【0063】 Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments. [Explanation of Symbols] 【0064】 1…Butterfly valve 2... Valve box 3… Valve body 9,24…Connecting members 11,33…Valve body and seat 12... Shaft 13,14,25,26…Protrusion 18…Shaft housing groove 19, 20, 31, 32… Grooves for housing protrusions

Claims

[Claim 1] In a butterfly valve installed in a pipeline through which fluid flows, A valve body connected to the aforementioned pipeline and having a fluid passage, A valve body that rotates inside the valve casing to open and close the flow path, A connecting member connected to the edge of the valve body, Equipped with, The connecting member has a valve seat that abuts against the valve body when the valve body is closing the flow path, and a projection that protrudes toward the interior of the valve body. The edge of the valve body has a projection-accommodating groove for accommodating the projection, The connecting member has the projection at its end, and the projection extends from the end toward the center in the thickness direction of the valve body. The valve body seat has a plurality of projections, the edge of the valve body has a plurality of projection-accommodating grooves, and each of the projections corresponds to each of the projection-accommodating grooves. When each of the aforementioned protrusions is housed in the groove for housing the protrusions, the valve body is tightly fitted to the connecting member. A butterfly valve characterized by the following features. [Claim 2] A connection strengthening agent is interposed between the connecting member and the edge of the valve body. The butterfly valve according to feature 1. [Claim 3] A method for manufacturing a butterfly valve comprising: a valve body connected to a pipeline through which a fluid flows and having a fluid passage; a valve element that rotates inside the valve body to open and close the passage; and a connecting member connected to the edge of the valve element, wherein the connecting member has a valve seat that abuts against the valve body when the valve element closes the passage, and a projection that protrudes from the valve seat, the edge of the valve element has a projection-accommodating groove for accommodating the projection, the connecting member has the projection at its end, the projection protrudes from the end toward the center in the thickness direction of the valve element, the valve seat has a plurality of projections, the edge of the valve element has a plurality of projection-accommodating grooves, each of the projections corresponds to each of the projection-accommodating grooves, and when each of the projections is accommodated in the projection-accommodating groove, the valve element is tightly fitted to the connecting member, Forming step of forming the valve body seat, A pressing step for pressing the connecting member, The system includes a deformation step of deforming the projection that is in contact with the projection housing groove, A method for manufacturing a butterfly valve, characterized by the following: