Butterfly valve

Abstract

To provide a butterfly valve that allows for easy installation of a valve element into a valve body.SOLUTION: A butterfly valve 1 comprises a valve body 10 having a fluid passage 11, valve stem pieces 20U, 20D rotatably inserted into the fluid passage 11, and a valve element 30 supported on the valve stem pieces 20U, 20D, and can switch the fluid passage 11 between a closed state and an open state by rotation of the valve element 30. The valve element 30 comprises a first valve element 30A and a second valve element 30B and has a valve seal 40 which is eccentrically disposed. The valve seal 40 is sandwiched between the first valve element 30A and the second valve element 30B and contacts the inner circumferential surface of the fluid passage 11 in the closed state. The valve stem pieces 20U, 20D have engaging parts 25U, 25D on the valve element-supporting side, and engaged parts 35U, 35D are provided on one surface side of the valve element 30. The engaging parts 25U, 25D and the engaged parts 35U, 35D can engage one another from an axial direction of the fluid passage 11 in the open state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a butterfly valve to be installed in a pipe (fluid passage) through which various fluids flow. [Background technology]

[0002] Conventionally, butterfly valves have been used to open and close piping (fluid passages) (see, for example, Patent Document 1). The butterfly valve described in Patent Document 1 comprises a valve stem arranged so as to intersect with the fluid passage in a valve body, and a valve disc attached to the valve stem and rotating integrally with the valve stem, the valve disc sandwiching a rubber sheet that makes sliding contact with the inner peripheral surface of the valve body, and the butterfly valve that opens and closes the fluid passage by rotating the valve stem and valve disc integrally has a configuration in which at least a portion of the sliding contact portion of the rubber sheet of the valve disc with the inner peripheral surface of the valve body is coated with ultra-high molecular weight polyethylene.

[0003] Also known is a butterfly valve in which the valve body is pre-assembled with the valve stem, and then the valve body is assembled into the piping (see, for example, Patent Document 2). The butterfly valve described in Patent Document 2 has the above-mentioned configuration, which improves the ease of assembly of the valve body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-62914 [Patent Document 2] Special Publication No. 46-14302 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the butterfly valve described in Patent Document 1 has a structure in which a valve stem is inserted into a valve disc, so the valve stem needs to be inserted into the valve disc after the valve disc is assembled into the valve body. Therefore, with the butterfly valve described in Patent Document 1, it is difficult to align the valve stem and valve disc, which may make assembly difficult.

[0006] Furthermore, the butterfly valve described in Patent Document 2 has a valve stem that is divided into two parts, an upper part and an lower part, and is inserted into stem holders attached to the top and bottom of the valve disc (valve plate). Furthermore, in the butterfly valve described in Patent Document 2, the valve stem is pre-assembled into the valve body, and the tip of the valve stem is inserted into the stem holder while the valve disc is rotated inside the piping. Therefore, the butterfly valve described in Patent Document 2 is structured with a gap between the valve disc and the valve stem, so that the valve stem and stem do not interfere with each other when the valve disc is rotating.

[0007] However, the butterfly valve described in Patent Document 2 has a gap to prevent the stem holder from interfering with the valve stem, which makes it difficult to center the stem and the valve body, raising concerns that the assembly accuracy of the valve body may be reduced.

[0008] Furthermore, when a butterfly valve is in a state where the fluid passage is blocked (closed state) by the disc, fluid pressure is applied to the disc's circular surface. Therefore, butterfly valves are generally designed to provide the disc with appropriate rigidity to reduce the maximum stress that tends to occur at the center of the disc. Meanwhile, lightweight discs are required for the purposes of improving ease of assembly and reducing disc material costs, and a certain degree of disc bending is unavoidable. However, if the disc is allowed to bend, the bending of the disc due to fluid pressure is transmitted as a large bending stress to the stem (or each stem segment in the case of a segmented stem). Therefore, there is a demand for a butterfly valve that combines lightweight discs with sufficient bending rigidity.

[0009] Therefore, an object of the present invention is to provide a butterfly valve that allows the valve disc to be easily assembled into the valve body, has high accuracy, and can reduce costs. Another object of the present invention is to provide a butterfly valve that ensures the rigidity of the valve disc and can be made lightweight. [Means for solving the problem]

[0010] (1) The butterfly valve of the present invention, which is provided to solve the above-mentioned problems, comprises a valve body having a fluid passage extending from one end side to the other end side, a pair of valve stems rotatably supported on the valve body and inserted into the fluid passage from both radial sides of the fluid passage, and a valve body disposed inside the fluid passage and supported by the pair of valve stems, and by rotating the valve body around the axis of the valve stems, the valve body can be switched between a closed state in which the fluid passage is blocked by the valve body and an open state in which the fluid passage is opened (a butterfly valve in a closed state and an open state (where the valve element is open when the valve element is released, and the open state that ensures approximately the largest fluid passage will be referred to here as the open state), the valve element comprises at least a first valve element and a second valve element, and has a valve seal arranged eccentrically from the axis of the pair of valve stem pieces, the valve seal is sandwiched between the first valve element and the second valve element, and abuts against the inner peripheral surface of the fluid passage in the radial direction when the fluid passage is closed by the valve elements, the pair of valve stem pieces have engaging portions on the support side of the valve element, and one side of the forming surface of the valve element is provided with a pair of engaged portions engageable with the pair of engaging portions at positions corresponding to the pair of engaging portions, and when the pair of engaged portions are engaged with the engaging portions, both sides of the pair of engaged portions are open along the forming surface of the valve element via the engaging portions, and the pair of engaging portions and the pair of engaged portions can be engaged with each other in the axial direction of the fluid passage in the open state.

[0011] The butterfly valve of the present invention, configured as described above in (1), can convert at least a portion of the force due to fluid pressure acting on the disc into shear force when the fluid passage is in a closed state (also referred to as a valve closed state) in which the disc blocks the fluid passage. That is, the butterfly valve of the present invention can convert the bending stress acting on the disc into shear force between the engaging portion of the stem and the engaged portion of the disc. Therefore, the butterfly valve of the present invention can reduce the bending stress acting on the stem. The engaging portion on the stem side can be formed convexly, for example, by flattening the tip of the stem, and the engaged portion on the disc can be formed concavely so that it can fit into the convex engaging portion along the surface of the disc. This allows the butterfly valve of the present invention to have a wide contact area between the engaging portion and the engaged portion, thereby smoothly converting the bending stress between the engaging portion and the engaged portion into shear force. Furthermore, in the butterfly valve of the present invention, the engaging portion and the engaged portion are constructed by a combination of concave and convex portions, which is expected to have the effect of automatically aligning the valve seal with the valve body when assembling the valve body to the valve stem.

[0012] Furthermore, by configuring the butterfly valve of the present invention as described above in (1), when the fluid passage is open (in an open state), the engaged portion of the disc and the engaging portion of the stem can be engaged along the forming surface of the disc. This allows the butterfly valve of the present invention to assemble the disc to the stem through the fluid passage with the pair of stems already assembled in the valve body. Therefore, the butterfly valve of the present invention can be easily assembled. Furthermore, since the stems are assembled in the valve body in advance, the butterfly valve of the present invention facilitates centering of the stems, improving assembly accuracy. Furthermore, since the butterfly valve of the present invention has a valve seal sandwiched between the first and second discs, it is possible to prevent the valve seal from shifting or falling off as the discs rotate.

[0013] (2) In the butterfly valve of the present invention described above, the pair of engaging portions and the pair of engaged portions may be fastened together by a fastening member along the axial direction of the fluid passage in the closed state after being engaged with each other.

[0014] The butterfly valve of the present invention, configured as described above in (2), can reduce backlash in the engagement between the engaging portion of the stem and the engaged portion of the disc. This further reduces the bending stress on the stem. As a result, the butterfly valve of the present invention can improve the accuracy of assembly of the disc into the valve body.

[0015] (3) In the butterfly valve of the present invention described above, the valve seal may be formed of a rubber sheet.

[0016] By adopting the configuration as described above in (3), the butterfly valve of the present invention can improve the adhesion between the valve body and the valve body (fluid passage), thereby improving the sealing performance.

[0017] (4) In the butterfly valve of the present invention described above, it is preferable that at least a portion of the valve seal is disposed in a position where it abuts against or is in close proximity to the pair of valve stems.

[0018] The butterfly valve of the present invention, by being configured as described above in (4), can suppress strong contact between the valve body and the valve seal when the valve disc rotates. Specifically, the butterfly valve of the present invention can suppress strong contact between the valve seal and the valve body that occurs on one side of the rotation due to eccentricity when the valve disc is in the open state and the valve seal is in sliding contact with the inner circumferential surface of the valve body. As a result, the butterfly valve of the present invention can suppress displacement and damage to the valve seal.

[0019] (5) In the butterfly valve of the present invention described above, the first valve body and the second valve body may each be substantially circular when viewed in the axial direction of the fluid passage, and may be connected to each other by a plurality of fastening members.

[0020] By configuring the butterfly valve of the present invention as described above in (5), the first valve body and the second valve body can be fastened together along their circumferences, thereby increasing the rigidity of the valve bodies of the butterfly valve of the present invention.

[0021] (6) In the butterfly valve of the present invention described above, the first valve body and the second valve body may be fastened together by a plurality of fastening members on the inner circumferential side of the valve seal.

[0022] By configuring the butterfly valve of the present invention as described above in (6), it is possible to provide fastening points for the first and second valve bodies on the inner circumferential side of the valve seal (for example, near the center of the first and second valve bodies), thereby further increasing the rigidity of the valve bodies of the butterfly valve of the present invention.

[0023] (7) In the butterfly valve of the present invention described above, the first valve body and the second valve body may be fastened together in the circumferential direction near the inner peripheral edge of the valve seal by a plurality of fastening members.

[0024] The butterfly valve of the present invention, by being configured as described above in (7), can suppress variations in fastening strength (strength loss) in the circumferential direction of the valve seal. This allows the butterfly valve of the present invention to improve sealing performance. Furthermore, the butterfly valve of the present invention, by being configured as described above in (7), can improve the retention of the valve seal on the valve body. This allows the butterfly valve of the present invention to suppress detachment of the valve seal.

[0025] (8) In the butterfly valve of the present invention described above, the valve seal may have at least one protrusion, and the first valve body and the second valve body may have, on their mating surfaces, accommodation portions for accommodating the protrusion.

[0026] The butterfly valve of the present invention has the configuration described in (8) above, whereby the protrusions (also called ears) engage with the housing, thereby reducing the effects of forces such as sliding torque due to sliding contact with the inner circumferential surface of the valve body and flow torque due to the fluid. As a result, the butterfly valve of the present invention can further prevent the valve seal from falling off.

[0027] (9) In the butterfly valve of the present invention described above, the protrusion is formed to protrude greater than the depth of the storage portion in the storage direction, and the volume of the protrusion is formed to be smaller than the storage volume of the storage portion.

[0028] By configuring the butterfly valve of the present invention as described above in (9), when the protrusion of the valve seal is accommodated in the accommodation portion of the valve body, the protrusion of the valve seal is appropriately compressed, and the crushing allowance (compression allowance) of the valve seal can be released into the space in the accommodation portion. As a result, the butterfly valve of the present invention can comfortably accommodate the valve seal within the space in the accommodation portion, thereby reducing the load on the fastening members and fastening portions of the first and second valve bodies.

[0029] (10) In the butterfly valve of the present invention described above, the first valve body and the second valve body may be formed by forging.

[0030] The butterfly valve of the present invention can be made lightweight by adopting the configuration described above in (10). Furthermore, the butterfly valve of the present invention can be made lightweight by adopting the configuration described above in (10). Furthermore, the butterfly valve of the present invention can be made lightweight while maintaining the strength (rigidity) of the valve body by forming the R (radius) required to suppress stress concentration in the valve body without any additional processing.

[0031] (11) The butterfly valve of the present invention described above may be characterized in that the valve body is formed by forging, and the draft required for the forging is formed on the formed surface side where the engaged portion is formed, relatively larger than the non-formed surface side where the engaged portion is not formed in the valve body.

[0032] The butterfly valve of the present invention, by adopting the configuration described above in (11), can form the valve body using forging, which is easy to form into a thin-walled shape, thereby reducing the weight of the valve body. Also, by adopting the configuration described above in (11), the butterfly valve of the present invention can form the R (radius) required to suppress stress concentration in the valve body without any additional processing.

[0033] (12) The butterfly valve of the present invention described above may be characterized in that the valve body is formed by forging, and the draft required for the forging is formed relatively large in the opposite direction to the eccentricity direction of the valve body.

[0034] The butterfly valve of the present invention, configured as described above in (12), concentrates the draft on the opposite side of the eccentric valve disc, thereby ensuring a clearance for the valve seal to accommodate eccentricity. In other words, the butterfly valve of the present invention utilizes the draft required for forging the valve body to ensure a clearance for the valve seal to accommodate eccentricity, thereby improving the production efficiency of the valve body and reducing manufacturing costs. The draft may be formed at an inclination angle of, for example, about 7 degrees. [Effects of the Invention]

[0035] According to the present invention, it is possible to provide a butterfly valve that allows the valve disc to be easily assembled into the valve body, has high accuracy, and can reduce costs. Furthermore, according to the present invention, it is possible to provide a butterfly valve that ensures the rigidity of the valve disc and can be made lighter. [Brief explanation of the drawings]

[0036] [Figure 1]1 is an overall perspective view and an enlarged exploded perspective view of a main portion of a butterfly valve according to an embodiment of the present invention; [Figure 2] FIG. 2 is a front view seen from the fluid passage direction of FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along the arrow AA in FIG. 2. [Figure 4] 4 is an explanatory diagram showing a state in which the valve body is assembled to the valve stem in the butterfly valve of the present invention. FIG. [Figure 5] 1 is an explanatory diagram illustrating a state in which a valve body is in an open state in the butterfly valve of the present invention, as viewed from the axial direction of a fluid passage. FIG. [Figure 6] FIG. 4 is an explanatory diagram relating to the draft angle when forging the butterfly valve of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] A butterfly valve 1 according to one embodiment of the present invention will be described in detail below with reference to the drawings. Note that each drawing is a schematic representation for ease of understanding, and may differ from the actual shape, size, and arrangement of components. In this embodiment, the direction from right to left in FIG. 3 may be referred to as the positive pressure direction, and the direction from left to right in FIG. 3 may be referred to as the counter pressure direction. The right side in FIG. 3 may be referred to as the upstream side of the fluid passage 11, and the left side in FIG. 3 may be referred to as the downstream side of the fluid passage 11. However, the butterfly valve may also be used in a manner in which the forward and reverse pressure directions or the upstream and downstream directions in FIG. 3 are reversed.

[0038] As shown in FIGS. 1 to 3, the butterfly valve 1 of the present invention includes a valve body 10, a pair of valve stem pieces 20U, 20D (also referred to as valve stems 20U, 20D), a valve body 30, and a valve seal 40 (see FIG. 3).

[0039] The valve box 10 is formed, for example, in a substantially cylindrical shape. A fluid passage 11 is formed inside the valve box 10, extending from one end to the other end in the horizontal direction. As will be described in detail later, in this embodiment, the valve box 10 is manufactured by forging. In addition, a pair of upper and lower valve stem support portions 12U, 12D are provided in the vertical direction of the valve box 10 to rotatably support a pair of valve stems 20U, 20D.

[0040] The fluid passage 11 is formed in a cylindrical shape and allows various fluids (for example, liquids, gases, etc.) to flow through it. In this embodiment, a valve element 30 is disposed near the middle of the fluid passage 11 in the axial direction. The fluid passage 11 can be connected to an appropriate pipe.

[0041] The stem support portions 12U, 12D are formed to protrude upward and downward in the radial direction of the fluid passage 11. Holes 13U, 13D (see FIGS. 2 and 3) are formed in the stem support portions 12U, 12D along the upward and downward radial directions, respectively. The stem support portions 12U, 12D can rotatably support the stems 20U, 20D, which will be described later, by inserting the stems 20U, 20D into the holes 13U, 13D.

[0042] In this embodiment, the stem pieces 20U, 20D are arranged separately above and below in the radial direction of the fluid passage 11. The stem pieces 20U, 20D are each formed in a cylindrical shape. The stem pieces 20U, 20D are inserted into the holes 13U, 13D and rotatably supported by the stem piece supports 12U, 12D. The stem pieces 20U, 20D also pass through the holes 13U, 13D and are inserted into the fluid passage 11 from both radial sides of the fluid passage 11. Annular seals 21, 21 (see FIGS. 2 and 3) are attached to the stem pieces 20U, 20D. Therefore, the gaps between the holes 13U, 13D and the stem pieces 20U, 20D are sealed by the seals 21, 21. Therefore, the fluid flowing through the fluid passage 11 is prevented from leaking out from between the stem support portions 12U, 12D and the stem pieces 20U, 20D. In this embodiment, a key 22 is formed on the upper end side of the stem piece 20U. Although not shown, an appropriate drive source, handle, etc. is attached to the upper end side of the stem piece 20U, and by engaging with the key 22, idling of the stem piece 20U and the handle, etc. is prevented. In addition, engagement portions 25U, 25D are formed on the tips of the stem pieces 20U, 20D (the ends inserted into the fluid passage 11).

[0043] In this embodiment, the engaging portions 25U, 25D are formed in a convex shape by flattening the tip surfaces of the cylindrical valve stem pieces 20U, 20D. That is, the engaging portions 25U, 25D are formed on the support side of the valve disc 30 of the valve stem pieces 20U, 20D. The engaging portions 25U, 25D can engage with engaged portions 35U, 35D of the valve disc 30, which will be described later. The engaging portions 25U, 25D can be rotated to position the flat surfaces along the axial direction (fluid flow direction) of the fluid passage 11 (see FIG. 4).

[0044] 3, the valve element 30 is disposed inside the fluid passage 11 and is supported by a pair of valve stem pieces 20U, 20D. The valve element 30 includes a first valve element 30A and a second valve element 30B each formed in a substantially circular shape when viewed in the axial direction of the fluid passage 11. That is, the first valve element 30A and the second valve element 30B are each formed in a disk shape. The valve element 30 is formed in a circular shape when viewed from the front, with the first valve element 30A and the second valve element 30B fastened together by a plurality of fastening members 31 (e.g., bolts 31).

[0045] The first valve element 30A is disposed upstream of the fluid passage 11 on the right side of the drawing. The first valve element 30A is disposed upstream of the fluid passage 11 with respect to the axial centers of the valve stem pieces 20U and 20D. That is, the first valve element 30A is disposed eccentrically with respect to the axial centers of the valve stem pieces 20U and 20D. The first valve element 30A is formed, for example, by forging. The first valve element 30A is formed in a disk shape, and the inner circumferential side of the downstream forming surface is formed to be concave. Therefore, the first valve element 30A is lightweight. In addition, a portion of the downstream forming surface (also referred to as the mating surface) near the outer periphery of the first valve element 30A is formed to accommodate a valve seal 40 (described later). That is, the valve seal 40 is disposed eccentrically with respect to the axial centers of the valve stem pieces 20U and 20D.

[0046] The first valve body 30A is formed with a plurality of fastening portions 33 (e.g., screw holes) for fastening a plurality of bolts 31 in the circumferential direction near the inner peripheral edge of the accommodation portion 32. The first valve body 30A is formed with a plurality of fastening portions 33 for fastening a plurality of bolts 31 on the inner peripheral side of the valve seal 40 (accommodation portion 32).

[0047] The second valve body 30B is disposed downstream of the first valve body 30A in the fluid passage 11. The second valve body 30B is disposed slightly upstream of the axial center of the valve stem pieces 20U, 20D. That is, the second valve body 30B is disposed slightly eccentrically with respect to the axial center of the valve stem pieces 20U, 20D. The second valve body 30B is formed by forging into a substantially flat disk shape. A portion of an accommodation portion 32 for accommodating a valve seal 40 (described later) is formed near the outer periphery of the upstream forming surface (also referred to as the mating surface) of the first valve body 30A.

[0048] Furthermore, bolts 31 (fastening members 31) are threadedly engaged with the second valve body 30B at positions corresponding to the fastening portions 33 of the first valve body 30A. The first valve body 30A and the second valve body 30B are fastened together with a plurality of bolts 31 in an overlapping state, thereby integrally forming the valve body 30. This results in a valve body 30 that is strong enough to withstand a certain fluid pressure and is lightweight. Furthermore, by joining the first valve body 30A and the second valve body 30B, a convex-shaped accommodation portion 32 for accommodating the valve seal 40 is formed. That is, the accommodation portion 32 is formed on the mating surfaces of the first valve body 30A and the second valve body 30B. As will be described in detail later, the valve seal 40 is sandwiched between the first valve body 30A and the second valve body 30B with a portion of the valve seal 40 engaged with the accommodation portion 32.

[0049] Furthermore, engaged portions 35U and 35D are formed on one side (in this embodiment, the downstream side) of the forming surface of the second valve body 30B at positions corresponding to the engaging portions 25U and 25D. As shown in FIGS. 1, 4, and 5, the engaged portions 35U and 35D can engage with the engaging portions 25U and 25D of the stem pieces 20U and 20D from the direction of the forming surface of the valve body 30 along the axial direction of the fluid passage 11. Specifically, as shown in the enlarged exploded view of the main part (within the two-dot chain circle) in FIG. 1, the engaged portions 35U and 35D are formed in a concave shape, and are open on both sides along the forming surface of the second valve body 30B. In other words, when engaged with the engaging portions 25U and 25D, the pair of engaged portions 35U and 35D are open on both sides along the forming surface of the valve body 30 via the engaging portions 25U and 25D, respectively. Therefore, the engaged portions 35U, 35D can be engaged with the engaging portions 25U, 25D by fitting the engaging portions 25U, 25D into the openings.

[0050] Here, the engagement between the engaged portions 35U, 35D and the engaging portions 25U, 25D will be described in detail below. As shown in Fig. 4, first, the valve stem pieces 20U, 20D are rotated, and the flat surfaces of the engaging portions 25U, 25D are arranged along the axial direction of the fluid passage 11. Next, the valve element 30 is inserted into the fluid passage 11 so that the forming surface of the valve element 30 is oriented along the axial direction of the fluid passage 11. At this time, as shown in Fig. 5, the engaging portions 25U, 25D and the engaged portions 35U, 35D are arranged so that the openings thereof face each other. In this embodiment, when the valve stem pieces 20U, 20D rotate, the valve element 30 (valve seal 40) rotates eccentrically to be positioned in an open state relative to the fluid passage 11, and is arranged to the right of the fluid passage 11 in Fig. 5. The butterfly valve changes between open and closed states by rotating it approximately 90 degrees, but whether this rotation is clockwise or counterclockwise depends on the relationship with the drive source and handle.

[0051] As the valve element 30 is inserted into the fluid passage 11, the engaged portions 35U, 35D engage with the engaging portions 25U, 25D through the opening. That is, the pair of engaging portions 25U, 25D and the pair of engaged portions 35U, 35D can engage with each other in the axial direction of the fluid passage 11 when the fluid passage 11 is in an open state opened by the valve element 30. When the engaging portions 25U, 25D and the engaged portions 35U, 35D engage with each other, the stem pieces 20U, 20D are rotated counterclockwise, and the fluid passage 11 is closed by the valve element 30, resulting in a closed state. Next, the engaged portions 25U, 25D and the engaged portions 35U, 35D are fastened together by bolts 36, 36 (also referred to as fastening members 36, 36). As a result, the valve element 30 is integrally supported by the stem pieces 20U, 20D. That is, by rotating the valve stem pieces 20U, 20D about their axes, the valve body 30 switches between a closed state in which the fluid passage 11 is blocked and an open state in which the fluid passage 11 is opened. In this embodiment, bolts 36, 36 are threadedly engaged from the valve stem pieces 20U, 20D to the first valve body 30A.

[0052] The valve seal 40 is formed of a rubber sheet such as silicone rubber, and is capable of elastic deformation. The valve seal 40 is formed in an annular (ring-like) shape, as shown in Fig. 2. The valve seal 40 is formed in a convex shape in cross section, as shown in Fig. 3, and has protrusions 41, 41 (also referred to as ears 41, 41) formed on both sides of the base end portion (inner peripheral side).

[0053] The protrusions 41 are accommodated in a housing portion 32 formed at the mating surfaces of the first valve body 30A and the second valve body 30B. As a result, the protrusions 41 engage with the housing portion 32, and the valve seal 40 is sandwiched between the first valve body 30A and the second valve body 30B. The protrusions 41 protrude into the housing portion 32 to a depth d in the housing direction that is greater than the depth of the protrusions 41 in the housing portion 32. The volume of the protrusions 41 is smaller than the volume of the housing portion 32. In the present embodiment shown in FIG. 3, a portion of the inner circumferential side of one of the protrusions 41 is cut out, thereby improving the accommodation of the protrusion 41 in the housing portion 32.

[0054] The valve seal 40 is configured to abut against the radial inner circumferential surface of the fluid passage 11 when the fluid passage 11 is closed by the valve disc 30. As a result, when the fluid passage 11 is closed by the valve disc 30, the valve seal 40 seals (hermetically seals) the gap between the valve disc 30 and the fluid passage 11. Furthermore, the valve seal 40 is arranged so that at least a portion (in this embodiment, the downstream side surface of the portion protruding radially from the valve disc 30) abuts against the pair of valve stem pieces 20U, 20D. Therefore, when the valve disc 30 is opened relative to the fluid passage 11 (also referred to as the valve open state), the valve seal 40 can be prevented from coming into strong contact with the inner circumferential surface of the fluid passage 11 (valve box 10) due to eccentric rotation. Specifically, the butterfly valve 1 of the present invention can suppress strong contact between the valve seal 40 and the valve body 10 that occurs on one side of eccentric rotation when the valve disc 30 is in the open state and the valve seal 40 is in sliding contact with the inner circumferential surface of the valve body 10. In other words, by arranging the valve seal 40 in a position that contacts or is close to the valve stem pieces 20U, 20D, the valve stem pieces 20U, 20D act as stoppers against deformation of the valve seal 40, thereby suppressing some of the deformation of the valve seal 40 that occurs due to eccentric rotation.

[0055] In addition, in this embodiment, as described above, the first valve body 30A and the second valve body 30B are fastened by a plurality of bolts 31 (fastening members 31) in the circumferential direction near the inner peripheral edge of the valve seal 40. This ensures that the valve seal 40 is securely sandwiched between the first valve body 30A and the second valve body 30B, thereby preventing the valve seal 40 from falling off.

[0056] The above is the configuration of one embodiment of the butterfly valve 1 of the present invention. Next, details of setting the draft angle θ when manufacturing the valve body 10 by forging will be explained with reference to Figure 6. Note that while the illustration shows the draft angle θ formed in a straight line, the portion where the draft angle θ is formed need not be linear, but can also be formed in various shapes such as a circular arc.

[0057] When the valve body 10 is manufactured by forging, a draft angle θ (inclination angle θ) of, for example, approximately 7 degrees is required for removal from the die. Therefore, in this embodiment, the draft angle θ required for forging is formed relatively larger on the forming surface side of the valve body 30 where the engaged portions 35U, 35D (see FIG. 3 ) are formed, compared to the non-forming surface side where the engaged portions 35U, 35D are not formed. By adopting the above-described configuration, the butterfly valve 1 of the present invention can ensure a radius (R) in the valve body 10 that can suppress stress concentration without separately processing the valve body 10. Furthermore, the butterfly valve 1 of the present invention can ensure contact pressure between the valve seal 40 and the valve body 10 while suppressing interference between the valve body 30 and the valve body 10 by utilizing the above-described radius (R). Here, the draft angle θ is preferably formed relatively larger in the direction opposite to the eccentric direction of the valve body 30. This suppresses interference with the valve box 10 due to eccentric rotation of the valve disc 30, and therefore the valve box 10 can be manufactured using the draft angle θ without having to process the valve box 10 separately, which is expected to reduce costs and the weight of the valve box 10.

[0058] The above is one embodiment of the butterfly valve 1 of the present invention. Next, the effects achieved by the butterfly valve 1 of the present invention will be described below.

[0059] <Action and effect> The above-described butterfly valve 1 has the following characteristic configurations (A) to (L). Therefore, the butterfly valve 1 of the present invention can achieve the following unique effects that cannot be achieved by conventional techniques.

[0060] (A) The butterfly valve 1 of the present invention described above comprises a valve body 10 having a fluid passage 11 extending from one end side to the other end side, a pair of valve stems 20U, 20D rotatably supported on the valve body 10 and inserted into the fluid passage 11 from both radial sides of the fluid passage 11, and a valve element 30 disposed inside the fluid passage 11 and supported by the pair of valve stems 20U, 20D. By rotating the valve element 30 around the axis of the valve stems 20U, 20D, the valve element 30 can be switched between a closed state in which the fluid passage 11 is blocked by the valve element 30 and an open state in which the fluid passage 11 is opened. The valve element 30 comprises at least a first valve element 30A and a second valve element 30B, and a valve seal 40 disposed eccentrically from the axis of the pair of valve stems 20U, 20D. The valve seal 40 is attached to the first valve element 30A and the second valve element 30B. The pair of valve stem pieces 20U, 20D are clamped and abut against the radial inner surface of the fluid passage 11 when the fluid passage 11 is closed by the valve body 30. The pair of valve stem pieces 20U, 20D have engaging portions 25U, 25D on the support side of the valve body 30, and one side of the forming surface of the valve body 30 is provided with a pair of engaged portions 35U, 35D that can engage with the pair of engaging portions 25U, 25D at positions corresponding to the pair of engaging portions 25U, 25D. When the pair of engaged portions 35U, 35D are engaged with the engaging portions 25U, 25D, respectively, both sides are open along the forming surface of the valve body 30 via the engaging portions 25U, 25D, and the pair of engaging portions 25U, 25D and the pair of engaged portions 35U, 35D can engage with each other in the axial direction of the fluid passage 11 when in the open state.

[0061] By configuring the butterfly valve 1 of the present invention as described above in (A), when the fluid passage 11 is in a closed state (also referred to as a valve closed state) where the fluid passage 11 is blocked by the valve disc 30, at least a part of the force due to the fluid pressure acting on the valve disc 30 can be converted into shear force. That is, the butterfly valve 1 of the present invention can convert the bending stress acting on the valve disc 30 into shear force between the engaging portions 25U, 25D of the valve stem pieces 20U, 20D and the engaged portions 35U, 35D of the valve disc 30. Therefore, the butterfly valve 1 of the present invention can reduce the bending stress acting on the valve stem pieces 20U, 20D. Here, the engaging portions 25U, 25D on the stem pieces 20U, 20D side can be formed convexly by, for example, flattening the tip portions of the stem pieces 20U, 20D, and the engaged portions 35U, 35D on the valve body 30 side can be formed concavely so that they can be fitted along the forming surface of the valve body 30 relative to the convex engaging portions 25U, 25D. This allows the butterfly valve 1 of the present invention to have a wide contact area between the engaging portions 25U, 25D and the engaged portions 35U, 35D, and therefore allows for smooth conversion of bending stress to shear force between the engaging portions 25U, 25D and the engaged portions 35U, 35D. Furthermore, in the butterfly valve 1 of the present invention, the engaging portions 25U, 25D and the engaged portions 35U, 35D are constructed using a combination of concave and convex portions, which is expected to have the effect of automatically aligning the valve seal 40 with the valve box 10 when assembling the valve body 30 to the valve stem pieces 20U, 20D.

[0062] Furthermore, by configuring the butterfly valve 1 of the present invention as described above in (A), in the open state, the engaged portions 35U, 35D of the valve disc 30 and the engaging portions 25U, 25D of the valve stems 20U, 20D can be engaged along the forming surfaces of the valve disc 30. As a result, in the butterfly valve 1 of the present invention, the valve disc 30 can be assembled to the valve stems 20U, 20D through the fluid passage 11 with the pair of valve stems 20U, 20D pre-assembled in the valve body 10. Therefore, the butterfly valve 1 of the present invention can be easily assembled. Furthermore, in the butterfly valve 1 of the present invention, the valve stems 20U, 20D are pre-assembled in the valve body 10, so that the centering of the valve stems 20U, 20D is easy and assembly accuracy can be improved. Furthermore, in the butterfly valve 1 of the present invention, the valve seal 40 is sandwiched between the first valve body 30A and the second valve body 30B, so that the valve seal 40 can be prevented from shifting or falling off as the valve body 30 rotates.

[0063] (B) In the butterfly valve 1 of the present invention described above, the pair of engaging portions 25U, 25D and the pair of engaged portions 35U, 35D are engaged with each other, and then, in the closed state, are fastened by the fastening member 31 along the axial direction of the fluid passage 11.

[0064] By adopting the configuration (B) above, the butterfly valve 1 of the present invention can reduce backlash in the engagement between the engaging portions 25U, 25D of the stem pieces 20U, 20D (stalks 20U, 20D) and the engaged portions 35U, 35D of the valve body 30. This allows the butterfly valve 1 of the present invention to further reduce the bending stress applied to the stem pieces 20U, 20D. Therefore, the butterfly valve 1 of the present invention can improve the accuracy of assembling the valve body 30 into the valve box 10.

[0065] (C) The butterfly valve 1 of the present invention described above is characterized in that the valve seal 40 is formed from a rubber sheet.

[0066] By configuring the butterfly valve 1 of the present invention as described above in (C), the adhesion between the valve element 30 and the valve body 10 (fluid passage 11) can be improved, thereby improving sealing performance.

[0067] (D) In ​​the butterfly valve 1 of the present invention described above, the valve seal 40 is characterized in that at least a portion thereof is disposed in a position in contact with or adjacent to the pair of valve stem pieces 20U, 20D.

[0068] By being configured as described above in (D), the butterfly valve 1 of the present invention can suppress strong contact between the valve body 10 and the valve seal 40 when the valve disc 30 rotates. Specifically, the butterfly valve 1 of the present invention can suppress strong contact between the valve seal 40 and the valve body 10 that occurs on one side of the rotation due to eccentricity when the valve disc 30 is in the open state and the valve seal 40 is in sliding contact with the inner circumferential surface of the valve body 10. As a result, the butterfly valve 1 of the present invention can suppress displacement and damage to the valve seal 40.

[0069] (E) The butterfly valve 1 of the present invention described above is characterized in that the first valve body 30A and the second valve body 30B are each approximately circular when viewed in the axial direction of the fluid passage 11, and are connected to each other by a plurality of fastening members 31.

[0070] The butterfly valve 1 of the present invention has the configuration described above in (E), which allows the first valve body 30A and the second valve body 30B to be fastened together along their circumferences, thereby increasing the rigidity of the valve body 30 in the butterfly valve 1 of the present invention.

[0071] (F) The butterfly valve 1 of the present invention described above is characterized in that the first valve body 30A and the second valve body 30B are fastened together by a plurality of fastening members 31 on the inner circumferential side of the valve seal 40.

[0072] By configuring the butterfly valve 1 of the present invention as described above in (F), it is possible to provide fastening points for the first valve body 30A and the second valve body 30B on the inner circumferential side of the valve seal 40 (for example, near the center of the first valve body 30A and the second valve body 30B). This allows the butterfly valve 1 of the present invention to further increase the rigidity of the valve body 30.

[0073] (G) In the butterfly valve 1 of the present invention described above, the first valve body 30A and the second valve body 30B are fastened together in the circumferential direction near the inner peripheral edge of the valve seal 40 by a plurality of fastening members 31.

[0074] By adopting the configuration as described above in (G), the butterfly valve 1 of the present invention can suppress variations in the fastening strength (strength deficiency) of the valve seal 40 in the circumferential direction. This allows the butterfly valve 1 of the present invention to improve sealing performance. Furthermore, by adopting the configuration as described above in (G), the butterfly valve 1 of the present invention can improve the retention of the valve seal 40 on the valve body 30. This allows the butterfly valve 1 of the present invention to suppress detachment of the valve seal 40.

[0075] (H) In the butterfly valve 1 of the present invention described above, the valve seal 40 has at least one protrusion 41, and the first valve body 30A and the second valve body 30B have, on their mating surfaces, accommodation portions 32 that accommodate the protrusion 41.

[0076] By configuring the butterfly valve 1 of the present invention as described above in (H), the protrusions 41 (also referred to as ears 41) engage with the housing portion 32, thereby reducing the effects of forces such as sliding torque due to sliding contact with the inner circumferential surface of the valve box 10 and flow torque due to the fluid. Therefore, the butterfly valve 1 of the present invention can further prevent the valve seal 40 from falling off.

[0077] (I) In the butterfly valve 1 of the present invention described above, the protrusion 41 is formed to protrude greater than the depth of the accommodation portion 32 in the accommodation direction, and the volume of the protrusion 41 is formed to be smaller than the accommodation volume of the accommodation portion 32.

[0078] By configuring the butterfly valve 1 of the present invention as described above in (I), when the protrusion 41 of the valve seal 40 is accommodated in the accommodation portion 32 of the valve body 30, the protrusion 41 of the valve seal 40 is appropriately compressed, and the crushing allowance (compression allowance) of the valve seal 40 can be released into the space in the accommodation portion 32. As a result, the butterfly valve 1 of the present invention can comfortably accommodate the valve seal 40 within the space in the accommodation portion 32, thereby reducing the load on the fastening members 31 and fastening portions of the first valve body 30A and the second valve body 30B.

[0079] (J) The butterfly valve 1 of the present invention described above is characterized in that the first valve body 30A and the second valve body 30B are formed by forging.

[0080] The butterfly valve 1 of the present invention, by adopting the configuration as described above in (J), can form a lightweight valve element 30. Furthermore, the butterfly valve 1 of the present invention, by adopting the configuration as described above in (J), can form the R (radius) required to suppress stress concentration in the valve element 30 without any additional processing. This allows the butterfly valve 1 of the present invention to be lightweight while ensuring the strength (rigidity) of the valve element 30.

[0081] (K) The butterfly valve 1 of the present invention described above is characterized in that the valve box 10 is formed by forging, and the draft angle θ required for the forging is formed relatively larger on the formed surface side where the engaged portions 35U, 35D of the valve body 30 are formed, compared to the non-formed surface side where the engaged portions 35U, 35D are not formed.

[0082] By configuring the butterfly valve 1 of the present invention as described above in (K), the valve body 10 can be formed using forging, which is easy to form into a thin-walled shape, thereby reducing the weight of the valve body 10. Furthermore, by configuring the butterfly valve 1 of the present invention as described above in (K), the R (radius) required to suppress stress concentration can be formed in the valve body 10 without any additional processing.

[0083] (L) The butterfly valve 1 of the present invention described above is characterized in that the valve body 10 is formed by forging, and the draft angle θ required for the forging is formed relatively large in the direction opposite to the eccentricity direction of the valve body 30.

[0084] The butterfly valve 1 of the present invention, configured as described above in (L), can ensure a clearance for the valve seal 40 to accommodate eccentricity by concentrating the draft angle θ on the side opposite the eccentric valve disc 30. That is, the butterfly valve 1 of the present invention can ensure a clearance for the valve seal 40 to accommodate eccentricity by utilizing the draft angle θ required for forging the valve body 10, thereby improving the production efficiency of the valve body 10 and reducing manufacturing costs. Here, the draft angle θ may be formed at an inclination angle of, for example, about 7 degrees.

[0085] <<Variations>> The above are the effects obtained by the butterfly valve 1 according to one embodiment of the present invention. However, the butterfly valve 1 is not limited to the above embodiment and can be variously modified within the scope of the present invention. For example, the butterfly valve 1 may be formed in various shapes and sizes as long as it is as described above in (A). Furthermore, the butterfly valve 1 of the present invention may, for example, not include some or all of the configurations described in (B) to (L) above, or may include some or all of the configurations described in (B) to (L) above in addition to other configurations. Furthermore, while this embodiment has been described as a case where a positive pressure fluid flows from right to left in FIG. 3, the butterfly valve 1 of the present invention can also be used in a case where a reverse pressure fluid flows from left to right in FIG. 3. Even in such a case, the butterfly valve 1 of the present invention can convert the bending stress applied to the first valve body 30A and the second valve body 30B by the fluid into shear force, thereby reducing the bending stress applied to the valve stems 20U and 20D.

[0086] In this embodiment, the valve element 30 includes a first valve element 30A and a second valve element 30B, but various types of valve elements can be used, such as a single valve element or three or more valve elements. The valve element 30 can also be formed into various shapes, sizes, and materials. The butterfly valve 1 can also be used in various orientations depending on the manner of use (for example, the butterfly valve 1 can be positioned upside down or tilted to the left or right).

[0087] In this embodiment, the engaging portions 25U, 25D are formed convexly, and the engaged portions 35U, 35D are formed concavely. However, the engaging portions 25U, 25D and the engaged portions 35U, 35D can be formed in various shapes and sizes as long as they can engage with each other in the axial direction of the fluid passage 11. Furthermore, in this embodiment, the tip portions of the engaging portions 25U, 25D are formed flat along the forming surface of the valve body 30. However, the engaging surfaces of the engaging portions 25U, 25D and the engaged portions 35U, 35D can be formed in various shapes and sizes. For example, the engaging surfaces of the engaging portions 25U, 25D and the engaged portions 35U, 35D may be formed unevenly along the forming surface of the valve body 30, or may be formed as rough surfaces. In such cases, it is desirable to convert the stress acting on the valve stem pieces 20U, 20D into shear force. Furthermore, the engaging portions 25U, 25D and the engaged portions 35U, 35D may be interchanged. In this embodiment, the engaging portions 25U, 25D are formed in the same shape, but the engaging portions 25U, 25D may be formed in different shapes. In such a case, the shape of the engaged portions 35U, 35D may be changed to match the engaging portions 25U, 25D. In this embodiment, both sides of the engaged portions 35U, 35D are open along the formation surface of the valve body 30, but, for example, only one side may be open. In such a case, it is sufficient that the side of the engaged portions 35U, 35D that engages with the engaging portions 25U, 25D is open.

[0088] In this embodiment, the engaging portions 25U, 25D and the engaged portions 35U, 35D are engaged with each other and then fastened by the fastening member 31, but the engaging portions 25U, 25D and the engaged portions 35U, 35D may be fastened as needed.

[0089] In this embodiment, at least a portion of the valve seal 40 is disposed in contact with or adjacent to the pair of valve stems 20U, 20D, but the valve seal 40 may be disposed in various positions. When the valve seal 40 is disposed adjacent to the valve stems 20U, 20D, the distance between the valve stems 20U, 20D should be set taking into account the amount of eccentricity that occurs when the valve is opened and closed.

[0090] Furthermore, the first valve body 30A and the second valve body 30B are not limited to the above-described embodiment, and can be fastened at various positions. In this embodiment, the first valve body 30A and the second valve body 30B are fastened by the bolts 31, but this is not limiting, and the first valve body 30A and the second valve body 30B can be fastened using various fastening members. Furthermore, the number and arrangement of fastening members 31 can vary depending on the size and shape of the first valve body 30A, the second valve body 30B, and the valve seal 40.

[0091] Furthermore, the shape, size, and material of the valve seal 40 are not limited to those in the above embodiment, and various shapes, sizes, and materials can be used. For example, the valve seal 40 may not have a protrusion 41. In such a case, a protrusion may be provided on the housing portion 32 side, and an engaging portion for the protrusion may be provided on the valve seal 40 side. Furthermore, if the valve seal 40 does not have a protrusion 41, the valve seal 40 may be fixed with a bolt or the like. Furthermore, various shapes and sizes (volumes) can be used for the housing portion 32 depending on the shape, size, etc. of the valve seal 40.

[0092] In this embodiment, the first valve body 30A and the second valve body 30B are formed by forging, but the first valve body 30A and the second valve body 30B can be manufactured by various means. For example, in the butterfly valve 1 of the present invention, either or both of the first valve body 30A and the second valve body 30B may be formed by means other than forging (for example, casting). Furthermore, even when the first valve body 30A and the second valve body 30B are manufactured by forging, various forging means can be used. Furthermore, various materials can be used to form the first valve body 30A and the second valve body 30B.

[0093] Although the valve body 10 is formed by forging in this embodiment, the valve body 10 can be manufactured by various means. For example, the valve body 10 of the butterfly valve 1 of the present invention may be formed by means other than forging (e.g., casting). Even when the valve body 10 is manufactured by forging, various forging methods can be used. Various materials can also be used to form the first valve body 30A and the second valve body 30B. Although the butterfly valve 1 of the present invention is configured as described above in (K), the draft angle θ required for forging is not limited to this. The draft angle θ required for forging can be set to various inclination angles depending on the shape and size of the valve body 30, valve seal 40, etc. Although the butterfly valve 1 of the present invention is configured as described above in (L), the position at which the draft angle θ is formed can be set to various positions depending on the arrangement of the valve body 30 and valve seal 40, etc.

[0094] The foregoing are various embodiments and modifications of the butterfly valve according to the present invention, but the present invention is not limited to the above-described embodiments and modifications, and it will be readily apparent to those skilled in the art that other embodiments may be possible within the scope of the claims and in accordance with the teachings and spirit of the present invention. [Industrial Applicability]

[0095] INDUSTRIAL APPLICABILITY The present invention can be suitably used as a butterfly valve to be provided in a pipe (fluid passage) through which various fluids (gas, liquid, etc.) flow. [Explanation of symbols]

[0096] 1: Butterfly valve 10: Valve box 20U: Valve stem piece (valve stem) 20D: Valve stem piece (valve stem) 25: Engagement part 25U: Engagement part 25D: Engagement part 30: Valve body 30A: First valve body 30B: Second valve body 31: Bolt (fastening member) 35U: Engaged part 35D: Engaged part 40: Valve seal 41: Protrusion (ear part)

Claims

1. a valve body having a fluid passage extending from one end side to the other end side; a pair of valve stem pieces rotatably supported by the valve body and inserted into the fluid passage from both radial sides of the fluid passage; a valve body disposed inside the fluid passage and supported by the pair of valve stems; Equipped with By rotating the valve body around the axis of the valve stem piece, the valve body can be switched between a closed state in which the fluid passage is blocked by the valve body and an open state in which the fluid passage is opened, The valve body includes at least a first valve body and a second valve body, and has a valve seal disposed eccentrically from the axis of the pair of valve stem pieces, the valve seal is sandwiched between the first valve body and the second valve body, and abuts against an inner circumferential surface of the fluid passage in a radial direction when the fluid passage is closed by the valve body, The pair of valve stem pieces have engagement portions on the support side of the valve body, a pair of engaged portions engageable with the pair of engaging portions are provided at positions corresponding to the pair of engaging portions on one side of the forming surface of the valve body, When the pair of engaged portions are engaged with the engaging portions, both sides of the engaged portions are open along the formation surface of the valve body via the engaging portions, A butterfly valve, characterized in that the pair of engaging portions and the pair of engaged portions can be engaged with each other in the axial direction of the fluid passage in the open state.

2. 2. The butterfly valve according to claim 1, wherein the pair of engaging portions and the pair of engaged portions are engaged with each other and then fastened together by a fastening member along the axial direction of the fluid passage in the closed state.

3. 3. The butterfly valve according to claim 1, wherein the valve seal is formed of a rubber sheet.

4. 3. The butterfly valve according to claim 1, wherein at least a portion of the valve seal is disposed in contact with or adjacent to the pair of valve stems.

5. 3. The butterfly valve according to claim 1, wherein the first valve body and the second valve body are each substantially circular when viewed in the axial direction of the fluid passage, and are connected to each other by a plurality of fastening members.

6. 3. The butterfly valve according to claim 1, wherein the first valve body and the second valve body are fastened together by a plurality of fastening members on the inner circumferential side of the valve seal.

7. 3. The butterfly valve according to claim 1, wherein the first valve body and the second valve body are fastened together in the circumferential direction near the inner peripheral edge of the valve seal by a plurality of fastening members.

8. the valve seal has at least one projection; 3. The butterfly valve according to claim 1, wherein the first valve body and the second valve body have, on their mating surfaces, a receiving portion for receiving the protrusion.

9. The protrusion is formed to protrude larger than the depth of the housing portion in the housing direction, 9. The butterfly valve according to claim 8, wherein the volume of the protrusion is smaller than the volume of the accommodation portion.

10. 3. The butterfly valve according to claim 1, wherein the first valve body and the second valve body are formed by forging.

11. The valve body is formed by forging, 3. The butterfly valve according to claim 1, wherein a draft angle required for the forging is formed relatively larger on a forming surface side of the valve body where the engaged portion is formed than on a non-forming surface side where the engaged portion is not formed.

12. The valve body is formed by forging, 3. The butterfly valve according to claim 1, wherein the draft required for the forging is formed relatively large in a direction opposite to the eccentric direction of the valve body.

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