Butterfly valve

Abstract

To provide a butterfly valve that can provide a stable high compression surface pressure.SOLUTION: An opening and closing mechanism Y of a butterfly valve 1 includes a four-joint link mechanism FL and a second movable arm 93 that rotates along with rotation of a valve rod 40. A closed-valve length L3, connecting between a second connecting part R2 in a closed-valve state in which a valve body 50 is in close contact with a seat ring 20 and a rotation center R0, is equal to or less than the sum of a first arm length L1 connecting between a first connection part R1 and the rotation center R0 in the four-joint link mechanism FL, and a second arm length L2 connecting between the first connection part R1 and the second connection part R2 in the second movable arm 93. A rotation of the valve rod 40 exceeding a predefined angle changes a connection angle θ between the four-joint link mechanism FL and the second movable arm 93 in the first connection part R1, moving the valve body 50 along a flow passage F so as to be in close contact with the seat ring 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a butterfly valve that is connected to, for example, a pipe and adjusts the flow rate of a fluid in the pipe by opening and closing it, or switches between open and closed states. [Background technology]

[0002] As shown in Patent Document 1, a butterfly valve has been used in the past, which includes a valve body having a tubular flow path, a valve stem rotatably mounted on the valve body, a valve element that is rotated by the valve stem to open and close the flow path, and a seat ring mounted between the valve body and the valve element, and which adjusts the flow rate by opening and closing the flow of fluid, or switches between open and closed states.

[0003] However, in a butterfly valve such as that shown in Patent Document 1, the valve disc abuts against the seat ring in the closed state to block the flow. Therefore, when blocking the flow of fluids with small molecular sizes such as hydrogen or helium or extremely low temperature fluids such as cryogenic fluids, it is necessary to increase the compressive surface pressure between the seat ring and the valve disc, but it has been difficult to stably maintain a high compressive surface pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-185047 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a butterfly valve that can obtain a stable, high compression surface pressure. [Means for solving the problem]

[0006] The present invention provides a valve device comprising a valve body having a tubular flow path, a valve stem rotatably mounted on the valve body, a valve disc that is rotated by the valve stem to open and close the flow path, and a seat ring mounted between the valve body and the valve disc, and a rotational movement conversion mechanism is provided between the valve stem and the valve disc, which rotates the valve disc as the valve stem rotates from a valve open position to a predetermined angle, and moves the valve disc so as to come into close contact with the seat ring as the valve stem rotates beyond the predetermined angle, and the rotational movement conversion mechanism is provided with a rotating part that rotates as the valve stem rotates, and a rotary connecting body rotatably connected to the rotating part and the valve disc, and a connecting part rotatably connecting the rotary connecting body and the rotating part is referred to as a first connecting part. and a connecting portion where the rotary connecting body and the valve element are rotatably connected is defined as a second connecting portion, the distance between the rotation center of the rotary part and the first connecting portion in the rotating part is defined as a rotating portion length, and the distance between the first connecting portion and the second connecting portion in the rotary connecting body is defined as a connecting portion length, and the length of a straight line connecting the second connecting portion and the rotation center in a state where the valve element has moved to be in close contact with the seat ring is equal to or less than the sum of the rotation length and the connecting portion length, and the butterfly valve is such that when the valve stem rotates beyond the predetermined angle, the connecting angle between the rotary part and the rotary connecting body in the first connecting portion changes, and the valve element moves along the flow path to be in close contact with the seat ring.

[0007] The butterfly valve may be a central butterfly valve, or may be configured as a primary eccentric butterfly valve or a secondary eccentric butterfly valve. The valve box is also called a valve body, housing, or valve body. The seat ring is sometimes called a valve seat. The rotational movement conversion mechanism may move in the direction of fluid flow or in a direction intersecting the direction of fluid flow, as long as it can move the valve body so as to be in close contact with the seat ring.

[0008] According to the present invention, a stable high compressive surface pressure can be obtained. In more detail, the rotational movement conversion mechanism in the butterfly valve rotates the valve element using a valve stem, causing the valve element to abut against a seat ring to open and close the flow path in the valve body. As the valve stem rotates from the open position to a predetermined angle, the valve element also rotates, and as the valve stem rotates beyond the predetermined angle, the valve element can be moved so that it is in close contact with the seat ring.

[0009] The rotational movement conversion mechanism includes a rotating part that rotates in conjunction with the rotation of the valve stem, and a rotary coupling body that is rotatably coupled to the rotating part and the valve disc. In the rotating part, the length of the line connecting the second coupling body and the rotation center when the valve disc has moved to contact the seat ring is shorter than the sum of the length of the rotational part, which is the distance between the center of rotation of the rotating part and the first coupling body, which rotatably couples the rotary coupling body and the rotating part, and the length of the coupling body, which is the distance between the first coupling body and the second coupling body, which rotatably couples the rotary coupling body and the valve disc. When the valve stem rotates beyond the predetermined angle, the coupling angle between the rotating part and the rotary coupling body at the first coupling body changes, and the valve disc moves along the flow path to contact the seat ring. As a result, in the closed valve state, the valve disc and the seat ring are in close contact with each other under high compressive surface pressure. Therefore, even when blocking the flow of a fluid with a small molecular size or a fluid at an extremely low temperature such as cryogenic temperature, the fluid will not leak out from between the seat ring and the valve body, and the flow path can be reliably blocked.

[0010] As an aspect of this invention, when the valve stem is rotated beyond the predetermined angle, the connecting angle may become wider than the connecting angle when the valve stem is rotated up to the predetermined angle, and the length connecting the second connecting portion and the center of rotation may become longer.

[0011] This invention provides a so-called crank mechanism, and by rotating the valve stem beyond a predetermined angle, the valve element moves along the flow path so as to come into close contact with the seat ring, thereby achieving a closed valve state in which the valve element and the seat ring are in close contact with each other under high compressive surface pressure.

[0012] As a further aspect of the present invention, in a valve-closed state in which the valve body and the seat ring are in close contact with each other, the rotation center, the first connecting portion, and the second connecting portion may be aligned in a straight line. With this invention, when the valve body and the seat ring are in a closed state and in close contact with each other, even if an external force acts on the valve body from the fluid in the valve opening direction, the center of rotation, the first connecting portion, and the second connecting portion are aligned in a straight line, so that the closed state can be reliably maintained against the external force.

[0013] As another aspect of the present invention, a movement direction restricting means may be provided for restricting the movement direction of the valve element along the flow path. According to this invention, by rotating the valve stem beyond the predetermined angle, the direction of movement of the valve element moving toward the seat ring can be restricted to a direction along the flow path, and the valve element and the seat ring can be placed in close contact with each other under high compression surface pressure to form a closed valve state.

[0014] As another aspect of the present invention, the movement direction restricting means may connect the rotation center and the second connecting portion, and may be configured to be movable relative to the rotation center. According to this invention, the direction of movement of the valve disc moving toward the seat ring due to rotation of the valve stem beyond the predetermined angle can be restricted with a simple structure.

[0015] In another aspect of the present invention, the rotating part may be a four-bar link mechanism in which the positions of the valve stem and the rotation center are fixed, and which is provided with a driving body that is connected to the valve stem and rotates together with the valve stem, a passive body that connects the rotation center and the first connecting part, and an intermediate body that connects the driving body and the passive body.

[0016] According to this invention, a small rotational force of the valve stem causes the valve body and the seat ring to come into close contact with each other with a high compressive surface pressure acting thereon. In detail, a large rotational force is required to directly apply the rotational force of the valve stem to tightly contact the valve disc and the seat ring under a high compressive surface pressure.In contrast, the rotating part is a four-bar link mechanism in which the positions of the valve stem and the rotation center are fixed, and the rotating part is provided with a driving body that is connected to the valve stem and rotates together with the valve stem, a driven body that connects the rotation center and the first connecting part, and an intermediate body that connects the driving body and the driven body.Therefore, compared to when the rotational force of the valve stem is directly applied, a smaller rotational force is required to tightly contact the valve disc and the seat ring under a high compressive surface pressure.

[0017] As another aspect of the present invention, the rotating portion may be a driving body that is connected to the valve stem and the first connecting portion and rotates together with the valve stem. According to this invention, the rotational force of the valve stem can be used to move the valve element along the flow path using a driving body with a simple structure.

[0018] In another aspect of the present invention, when the valve stem is rotated beyond the predetermined angle, the connecting angle may become narrower than the connecting angle when the valve stem is rotated up to the predetermined angle, and the length connecting the second connecting portion and the center of rotation may become shorter.

[0019] According to this invention, when the valve stem rotates beyond a predetermined angle, the connecting angle narrows and the length connecting the second connecting part and the rotation center shortens, thereby moving the valve element along the flow path so as to be in close contact with the seat ring, thereby achieving a closed valve state in which the valve element and the seat ring are in close contact with each other under high compression surface pressure. [Effects of the Invention]

[0020] The present invention provides a butterfly valve that can obtain a stable high compression surface pressure. [Brief explanation of the drawings]

[0021] [Figure 1] An explanatory diagram of a butterfly valve. [Figure 2] An explanatory diagram of a butterfly valve. [Figure 3] An explanatory diagram of a butterfly valve. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] An explanatory diagram of a butterfly valve. [Figure 7] An explanatory diagram of a butterfly valve. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] FIG. 10 is an explanatory diagram of an opening and closing mechanism according to another embodiment. [Figure 13] FIG. 10 is an explanatory diagram of an opening and closing mechanism according to still another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of the present invention will be described below with reference to the drawings. 1 to 3, 6 and 7 are explanatory diagrams of the butterfly valve 1, FIGS. 4 and 5 are exploded perspective views of the main body mechanism X, FIGS. 8 and 9 are explanatory diagrams of the opening and closing mechanism Y, and FIGS. 10 and 11 are explanatory diagrams of the opening and closing operation of the butterfly valve 1.

[0023] More specifically, Fig. 1(a) is a schematic perspective view showing the front, right side, and plan of the butterfly valve 1, and Fig. 1(b) is a schematic perspective view showing the back, left side, and bottom of the butterfly valve 1. Fig. 2(a) is a front view of the butterfly valve 1 in an open state, Fig. 2(b) is a rear view of the butterfly valve 1 in the same state, Fig. 2(c) is a front view of the butterfly valve 1 in a closed state, and Fig. 2(d) is a rear view of the butterfly valve 1 in the same state.

[0024] FIG. 3(a) shows a view taken along the arrow AA in FIG. 1(a) in the open state, and FIG. 3(b) shows a view taken along the arrow BB in FIG. 3(a). 4 is a schematic exploded perspective view showing the front, right side and top of the main body mechanism X, and FIG. 5 is a schematic exploded perspective view showing the back, left side and bottom of the main body mechanism X. As shown in FIG.

[0025] FIG. 6(a) is a schematic perspective view showing the front, right side, and top view of the butterfly valve 1 in the open state, with the body mechanism X seen through, and FIG. 6(b) is a schematic perspective view showing the front, right side, and top view of the butterfly valve 1 in the closed state, with the body mechanism X seen through.

[0026] FIG. 7(a) is a schematic perspective view showing the back, left side, and bottom of the butterfly valve 1 in an open state, with the body mechanism X seen through, and FIG. 7(b) is a schematic perspective view showing the back, left side, and bottom of the butterfly valve 1 in a closed state, with the body mechanism X seen through.

[0027] 8(a) is a schematic exploded perspective view showing the front, right side and top of the opening / closing mechanism Y, and FIG. 8(b) is a schematic exploded perspective view showing the back, left side and bottom of the opening / closing mechanism Y. FIG. FIG. 9 shows an enlarged view of part a in FIG. 8(a).

[0028] 10A, which explains the opening and closing operation of the butterfly valve 1, shows a view taken along the arrow CC in FIG. 3B in the open state, and FIG. 10B shows a view taken along the arrow DD in FIG. 3B in the same state.

[0029] Also, Figure 10(c) shows a view from the CC arrow in Figure 3(b) in a 45-rotation state in which the valve stem 40 has been rotated 45 degrees clockwise from the open valve state, and Figure 10(d) shows a view from the DD arrow in Figure 3(b) in the same state.

[0030] Furthermore, Figure 10(e) shows a view from the CC arrow in Figure 3(b) in a 90-degree rotated state in which the valve stem 40 has been rotated clockwise by a predetermined angle of 90 degrees from the open valve state, and Figure 10(f) shows a view from the DD arrow in Figure 3(b) in the same state.

[0031] Furthermore, Figure 10(g) shows a view from the CC arrow in Figure 3(b) in the closed state where the valve stem 40 has been rotated 110 degrees clockwise from the open state, and Figure 10(h) shows a view from the DD arrow in Figure 3(b) in the same state. FIG. 11(a) shows an enlarged view of part b in FIG. 10(a), and FIG. 11(b) shows an enlarged view of part c in FIG. 10(g).

[0032] In the above drawings, bolt holes for inserting or fastening bolts, the bolts themselves, and the like are partially omitted. 1(a), the vertical direction is the height direction H, the direction connecting the upper left and lower right is the width direction W, and the direction connecting the upper right and lower left is the depth direction D.

[0033] Furthermore, the upper side of the height direction H is referred to as the upper side HU, and the lower side is referred to as the lower side HD. Furthermore, in the width direction W, which is the direction connecting the upper left and lower right, the upper left side is referred to as the left side WL, the lower right side is referred to as the right side WR, and in the depth direction D, which is the direction connecting the upper right and lower left, the upper right side is referred to as the back side DB, and the lower right side is referred to as the front side DF. Regardless of the width direction W or the depth direction D, the direction perpendicular to the height direction H is referred to as the horizontal direction.

[0034] The butterfly valve 1 is a valve device connected to a pipeline (not shown) such as a pipe arranged along the depth direction D, and is used to allow or block the flow of fluid such as a liquid through the pipeline, and also to adjust the flow rate, and is also known as a central butterfly valve.

[0035] The butterfly valve 1 comprises a valve box 10 having a flow path F therein along the depth direction D, a main body mechanism X having at least a seat ring 20, a valve stem 40 rotatably mounted on the valve box 10, and an opening / closing mechanism Y having at least a valve body 50 that is rotated by the valve stem 40 and opens and closes the flow path F.

[0036] As shown in FIGS. 4 and 5, the main body mechanism X includes a valve box 10, a seat ring 20, a retaining ring 31, and a fixing ring 32. The valve box 10 has a tube main body 11 formed in an approximately cylindrical shape in an inverted position, with a flow path F running along the depth direction D inside and penetrating in the depth direction D, and base portions 12 provided on both sides of the tube main body 11 in the height direction H, and is formed to a predetermined length in the depth direction D.

[0037] As shown in FIG. 4, a mounting portion 111 for mounting a seat ring 20 is provided on the front side of the tube main body 11 formed in a substantially cylindrical shape. The attachment portion 111 protrudes radially inward from the inner surface of the tube main body 11 at a position from the end of the front side DF of the tube main body 11 toward the rear side DB, and has a plurality of bolt holes (not shown) arranged at predetermined intervals in the circumferential direction for fastening bolts to fasten a fixing ring 32 (described later). The radially inner side of the attachment portion 111 protruding radially inward from the inner surface of the tube main body 11 serves as a communication opening 112.

[0038] The base portion 12 has a predetermined thickness in the height direction H, and is formed in a rectangular shape that is longer in the depth direction D than in the width direction W when viewed from the height direction H, and has a through hole 121 in the center that penetrates in the height direction H and communicates with the flow path F. The base portions 12 are disposed on both sides of the cylindrical main body portion 11 in the height direction H, and are integrally formed therewith. As described above, the valve box 10, in which the cylindrical main body portion 11 and the base portions 12 are integrally formed, is made of metal.

[0039] The seat ring 20 is a sealing member that is attached to the mounting portion 111 of the tube main body portion 11 and abuts against the valve body 50 of the opening / closing mechanism Y described later to seal the flow opening 112, and is formed in a ring shape when viewed from the depth direction D. The seat ring 20 is attached to the attachment portion 111 and is formed with an appropriate cross-sectional shape for sealing by contacting the valve body 50, and is made of an elastic material having appropriate elasticity.

[0040] The pressure ring 31 is a flat ring plate formed in a ring shape that is approximately the same as the seat ring 20 when viewed from the depth direction D, and is positioned between the seat ring 20 and a fixing ring 32 for fixing the seat ring 20 attached to the mounting portion 111 to the mounting portion 111. The press ring 31 is made of a plate material having higher rigidity than the seat ring 20, such as resin or metal.

[0041] The fixing ring 32 is a fixing member for fixing the seat ring 20 attached to the mounting portion 111 to the mounting portion 111, and is provided with a plurality of bolt placement portions 321 at predetermined intervals in the circumferential direction, on which bolts for fixing the seat ring 20 to the mounting portion 111 are placed. The fixing ring 32 is made of a material, such as resin or metal, that has appropriate rigidity to withstand the fastening force of the bolts.

[0042] By using the seat ring 20, the pressing ring 31, and the fixing ring 32 configured as described above, the seat ring 20 can be attached and fixed to the attachment portion 111 of the tube main body portion 11. Specifically, the seat ring 20 is attached to the attachment portion 111 of the tube main body 11, and the press ring 31 is placed on the front side DF of the attachment portion 111. Then, the fixing ring 32 is placed on the front side DF of the attachment portion 111, and the bolts are fastened to the attachment portion 111 of the tube main body 11 at the bolt placement portion 321 of the fixing ring 32. This allows the seat ring 20, which is placed between the attachment portion 111 and the fixing ring 32, to be fixed while being pressed down by the press ring 31, thereby forming a main body mechanism X in which the seat ring 20 is attached to the valve box 10.

[0043] The opening / closing mechanism Y, which is assembled to the main body mechanism X and constitutes the butterfly valve 1, includes a valve stem 40 rotatably mounted on the valve box 10, and a valve element 50 that is rotated by the valve stem 40 and opens and closes the flow path F, as well as a fixed base 60, a push-in base 51, a cam link 70, a central shaft 80, and a connecting arm 90. There is one valve element 50, one push-in base 51, one cam link 70, and one central shaft 80, and two valve stems 40, two fixed bases 60, and two connecting arms 90 (91, 92, 93), which are arranged symmetrically above and below.

[0044] The valve stem 40 is formed in a substantially cylindrical shape with a predetermined length in the height direction H. Of the two valve stems 40 provided in the butterfly valve 1, the valve stem 40A arranged in the upper HU protrudes into the upper HU when assembled to the valve box 10 and is provided with an operating part 41 to which a handle or a gripping part of an actuator can be attached.

[0045] In contrast, the valve stem 40B arranged in the lower HD is oriented upside down relative to the valve stem 40A as shown in FIG. 3(b), and is formed shorter by the length of the operating portion 41 of the valve stem 40A. In the butterfly valve 1 described in this embodiment, when the valve stem 40 rotates clockwise in a plan view, it rotates in the valve closing direction, and when the valve stem 40 rotates counterclockwise in a plan view, it rotates in the valve opening direction.

[0046] The valve body 50 is rotated by the valve rod 40 via the push-in base 51 described later to open and close the flow path F, and is formed in an approximately disk shape centered on a horizontal axis perpendicular to the height direction H. Specifically, the valve element 50 is a metal disk having a diameter slightly larger than the flow opening 112 of the cylindrical main body 11 of the valve box 10, and is erected with its central axis in the horizontal direction. Note that, in the orientation shown in Figure 8(a), the valve element 50 is slightly tapered in diameter toward the front side DF.

[0047] The push-in base 51 is a base for fixing the valve body 50 and rotating it by rotating the valve rod 40, and is provided with a fixed surface portion 52 that extends along the vertical direction (height direction H), horizontal portions 53 that are provided on both sides of the fixed surface portion 52 in the height direction H and extend horizontally from the center of the width direction of the fixed surface portion 52, and a vertical portion 54 that connects the end of the horizontal portion 53 on the opposite side of the fixed surface portion 52 in the vertical direction (height direction H).

[0048] In detail, the fixing surface portion 52 is formed in a rectangular shape that is long in the height direction H, with a length in the width direction W that is shorter than the diameter of the valve body 50 and a length in the height direction H that is longer than the diameter of the valve body 50, and an attachment portion for attaching the valve body 50 is provided in the center.

[0049] The horizontal portion 53 has a rectangular cross section that is longer in the horizontal direction than in the height direction H, and is formed with a predetermined length in the horizontal direction.Furthermore, on the side of the fixed surface portion 52 of the horizontal portion 53, there is provided a connecting hole 55 that penetrates in the height direction H and is rotatably connected to the second movable arm 93 of the connecting arm 90 described later to form the second connecting portion R2.

[0050] Furthermore, a rotation center hole 56 is provided on the vertical portion 54 side of the horizontal portion 53, penetrating in the height direction H, rotatably connected to a first movable arm 92 of a connecting arm 90 (described later), and through which the central shaft 80 is inserted. The rotation center hole 56 has an elliptical shape that is long in the depth direction D when viewed from the height direction H. Specifically, the rotation center hole 56 has an elliptical shape that allows the inserted central shaft 80 to move in the depth direction D in accordance with the amount of movement of the valve body 50 in the depth direction D.

[0051] The horizontal portion 53 is formed in an oval shape and is provided with a rotation center hole 56 through which the central axis 80 is inserted and a connecting hole 55 that constitutes the second connecting portion R2, and functions as a movement direction regulating means that regulates the movement direction of the flow path F of the valve body 50, as described below.

[0052] The vertical portion 54 has the same cross-sectional shape as the horizontal portion 53, and connects the end of the horizontal portion 53 opposite the fixed surface portion 52 in the vertical direction (height direction H), and the horizontal portion 53 and the vertical portion 54 form a gate-shaped frame relative to the surface of the fixed surface portion 52.

[0053] The fixed base 60 is composed of a plate-shaped base body 61 fixed to the pedestal portion 12 of the valve box 10, and a cylindrical protruding portion 62 protruding in the height direction H from the base body 61. The fixed base 60 arranged on the upper HU of the valve box 10 has a cylindrical protrusion 62 extending from the bottom surface of the base body 61 toward the lower HD, and the fixed base 60 arranged on the lower HD of the valve box 10 has a cylindrical protrusion 62 extending from the top surface of the base body 61 toward the upper HU. In other words, the fixed base 60 arranged on the upper HU of the valve box 10 and the fixed base 60 arranged on the lower HD of the valve box 10 are arranged symmetrically in the vertical direction.

[0054] The base body 61 is formed in substantially the same shape as the base portion 12 of the valve box 10 in a plan view, and is configured to be fastened and fixed to the base portion 12 with bolts (not shown). The cylindrical protrusion 62 is cylindrical in shape with a diameter that allows it to be inserted into the through-hole 121 when the fixed base 60 is placed on the pedestal 12, and is formed at a height such that its tip reaches the flow path F, as shown in Figure 3(b).

[0055] At the tip of the cylindrical protrusion 62, a recessed fitting recess 63 is formed to fit over the end of the central shaft 80, which will be described later. Furthermore, an insertion hole 64 is formed in the center of the cylindrical protrusion 62 of the fixed base 60 in a plan view, penetrating in the height direction H and through which the valve stem 40 is inserted. The insertion hole 64 is a cylindrical space slightly larger than the valve stem 40.

[0056] The fixed base 60 arranged on the lower HD of the valve box 10 is provided with a support hardware 65 (see Figure 3) that supports the valve stem 40B inserted into the insertion hole 64 to prevent it from falling out, and the fixed base 60 of the upper HU is provided with a pull-out prevention ring 66 that prevents the inserted valve stem 40A from coming out.

[0057] The cam link 70 is disposed between the valve stems 40 provided on both sides in the height direction H, and is connected to both valve stems 40, rotating together with the valve stems 40 around the center of rotation of the valve stems 40. The cam link 70 includes a column portion 71 with an angular cross section disposed along the center of rotation of the valve stem 40, and L-shaped arm portions 72 that are L-shaped in plan view and provided at both ends of the column portion 71.

[0058] The L-shaped arm portion 72 is formed in an inverted L shape in a plan view by a first extending portion 721 extending horizontally from both ends of the column portion 71, from the edge of the end of the valve stem 40, and a second extending portion 722 extending horizontally from the tip of the first extending portion 721 in a direction perpendicular to the extending direction of the first extending portion 721. A connecting hole 73 is provided at the tip side of the second extending portion 722, penetrating in the height direction H and rotatably connecting to a drive arm 91 of a connecting arm 90 (described later) to form a third connecting portion R3.

[0059] The L-shaped arm portions 72 provided on both sides of the first extending portion 721 in the height direction H are arranged in the same direction in a plan view. The distance between the surfaces of the L-shaped arm portions 72 arranged on both ends of the column portion 71 in the height direction H that face each other in the height direction H is formed to be longer than the length between the outer sides of the horizontal portion 53 of the pushing base 51 in the height direction H, i.e., the length of the pushing base 51 in the height direction H. Furthermore, the cam link 70 may be configured so that the L-shaped arm portion 72 is detachable from the pillar portion 71, or the cam link 70 and the valve stem 40 may be configured as one unit.

[0060] The central axis 80 is cylindrical and made of steel, and when assembled to the main mechanism X, both ends in the height direction H are formed to a length that allows them to fit into the fitting recesses 63 provided on the tip surface of the cylindrical protrusion 62 of the fixed base 60.

[0061] The connecting arm 90 transmits the rotation input from the valve stem 40 via the cam link 70 to the pushing base 51, thereby rotating and moving the valve body 50, and is equipped with a drive arm 91, a first movable arm 92, and a second movable arm 93.

[0062] The drive arm 91 is an arm member that is rotatably connected to the L-shaped arm portion 72 of the cam link 70 and drives the pushing base 51 via movable arms 92, 93, and is formed in a plate shape with appropriate strength.

[0063] Near one end of the drive arm 91, there is provided a connecting hole 911 that penetrates in the height direction H and rotatably connects to the connecting hole 73 provided in the second extension portion 722 to form the third connecting portion R3. Near the other longitudinal end of the drive arm 91, there is provided a connection hole 912 that penetrates in the height direction H and is rotatably connected to the movable arms 92, 93 to form the first connection part R1.

[0064] The first movable arm 92 and the second movable arm 93 are rotatably connected to each other by a first connecting portion R1, and are arms attached to the horizontal portion 53, and are formed in the same shape. Specifically, the first movable arm 92 is formed in the shape of a plate with appropriate strength, and is rotatably connected to a rotation center hole 56 provided in the horizontal portion 53 of the push-in base 51 on one side in the longitudinal direction, and is provided with a rotation center hole 921 through which the central axis 80 is inserted.

[0065] The other longitudinal side of the first movable arm 92 is provided with a connecting hole 922 that penetrates in the height direction H and is rotatably connected to the connecting hole 912 and the second movable arm 93 to form the first connecting portion R1. The length connecting the center of the rotation center hole 921 and the center of the connecting hole 922 in the first movable arm 92 is defined as a first arm length L1.

[0066] The second movable arm 93 is formed in the same shape as the first movable arm 92 in a plate shape with appropriate strength, and has a connecting hole 931 on one side in the longitudinal direction that is rotatably connected to the connecting hole 912 and the connecting hole 922 to form the first connecting part R1.

[0067] On the other longitudinal side of the second movable arm 93, there is provided a connecting hole 932 that penetrates in the height direction H and is rotatably connected to the connecting hole 55 provided in the horizontal portion 53 of the push-in base 51 to form the second connecting portion R2.

[0068] In addition, the length connecting the center of connecting hole 931 and the center of connecting hole 932 in second movable arm 93 is defined as second arm length L2, and in movable arms 92 and 93 formed in the same shape, first arm length L1 and second arm length L2 are the same length.

[0069] The sum of the first arm length L1 of the first movable arm 92 and the second arm length L2 of the second movable arm 93 configured in this manner is the length between the center of the connecting hole 55 in the horizontal portion 53 of the push-in base 51 and the center of the far side of the oval-shaped rotation center hole 56, that is, the closed-valve state length L3 between the center (rotation center R0) of the central axis 80 and the second connecting portion R2 in the closed-valve state in which the valve body 50 described below is pressed against the seat ring 20, or a length slightly longer.

[0070] In addition, the first connecting portion R1, the second connecting portion R2, and the third connecting portion R3 can be configured by connecting holes that communicate with each other in the height direction H and connecting them rotatably with connecting shaft members such as bolts or crimping members. Two sets of connecting arms 90 each including a drive arm 91, a first movable arm 92, and a second movable arm 93 are provided and are arranged on both outer sides of the pushing base 51 in the height direction H.

[0071] Next, the assembly of the opening and closing mechanism Y having the valve body 50, the pushing base 51, the fixed base 60, the cam link 70, the central shaft 80 and the connecting arm 90 configured as described above will be described. First, the valve stem 40A, the cam link 70, and the valve stem 40B are assembled in the height direction H to be integrated.

[0072] Then, the valve body 50, the push-in base 51, the central axis 80 and the connecting arm 90 are assembled to the cam link 70, but the valve rod 40A and the valve rod 40B may also be assembled and integrated to the cam link 70 to which the valve body 50, the push-in base 51, the central axis 80 and the connecting arm 90 are assembled.

[0073] Specifically, the valve body 50 is attached to the fixing surface portion 52 of the push-in base 51 and integrated therewith. The drive arm 91, the first movable arm 92, and the second movable arm 93 are arranged in this order from the outside in the height direction H, and the connecting hole 912 of the drive arm 91, the connecting hole 922 of the first movable arm 92, and the connecting hole 931 of the second movable arm 93 are connected in the height direction H, and are rotatably connected by a connecting shaft member to assemble the connecting arm 90, and the first connecting part R1 is formed.

[0074] The drive arm 91 is positioned inside the cam link 70 in the height direction H, and the connecting hole 911 of the drive arm 91 is connected to the connecting hole 73 provided in the L-shaped arm portion 72 of the cam link 70 in the height direction H, and is rotatably connected by a connecting shaft member to form the third connecting portion R3.

[0075] The second movable arm 93 is positioned outside the height direction H of the horizontal portion 53 of the pushing base 51, and the connecting hole 932 of the second movable arm 93 is connected to the connecting hole 55 provided in the horizontal portion 53 of the pushing base 51 in the height direction H, and is rotatably connected by a connecting shaft member to form the second connecting portion R2.

[0076] The first movable arm 92 is disposed outside the horizontal portion 53 of the push-in base 51 in the height direction H, and the rotation center hole 921 of the first movable arm 92 is connected in the height direction H to the rotation center hole 56 provided in the horizontal portion 53 of the push-in base 51, and the central shaft 80 is inserted through and rotatably connected to form a rotation center R0. Note that the rotation center R0 serves as the center for rotating the push-in base 51 to which the valve disc 50 is attached, and is disposed at a distance DF from the valve stem center of the valve stem 40 on the near side.

[0077] Furthermore, in this assembled state, the central axis 80, which is the rotation center R0, is positioned in its normal position on the side of the connecting hole 55 in the oval rotation center hole 56, so the first movable arm 92 and the second movable arm 93, which are rotatably connected at the first connecting portion R1, are in a greatly bent state, that is, the connection angle θ between the first movable arm 92 and the second movable arm 93 at the first connecting portion R1 becomes narrow (see Figure 11(a)).

[0078] 11(a), the drive arm 91, first movable arm 92, and second movable arm 93, which are rotatably connected at the first connecting portion R1, extend in three directions at approximately equal intervals in the circumferential direction around the first connecting portion R1. In this embodiment, the connection angle θ between the first movable arm 92 and the second movable arm 93 at the first connecting portion R1 is 120 degrees.

[0079] In other words, when the central axis 80 serving as the center of rotation R0 is located at the normal position on the side of the oval rotation center hole 56 that is closer to the connecting hole 55, the valve element 50 is in a state where it is closer to the center of rotation R0. Conversely, when the valve element 50 is in a state where it is away from the center of rotation R0, the central axis 80 serving as the center of rotation R0 is located at the valve-closed position on the side of the oval rotation center hole 56 that is farther from the connecting hole 55.

[0080] In this way, the valve stem 40, valve body 50, push-in base 51, cam link 70, central axis 80 and connecting arm 90 are assembled, and the L-shaped arm portion 72 connecting the valve stem center, which is the center of rotation of the valve stem 40, to the third connecting portion R3 functions as the driving body, the first movable arm 92 connecting the rotation center R0 to the first connecting portion R1 functions as the passive body, and the drive arm 91 connecting the first connecting portion R1 to the third connecting portion R3 functions as the intermediate body.Furthermore, since the valve stem center and the rotation center R0 are fixed, a four-bar link mechanism FL is formed. In other words, the opening / closing mechanism Y is configured to rotate the valve body 50 in conjunction with the rotation of the valve rod 40, or to move the valve body 50 into the flow path F when the valve rod 40 rotates by a rotation of the valve rod 40 exceeding a predetermined angle, using a four-bar link mechanism FL, a second movable arm 93 rotatably connected to the four-bar link mechanism FL at a first connecting part R1, and a push-in base 51 having a horizontal part 53 to which the second movable arm 93 is rotatably connected at a second connecting part R2. Furthermore, the assembly order of the valve body 50, the push-in base 51, the cam link 70, the central shaft 80, and the connecting arm 90 is not limited to the above order, and they may be assembled in any appropriate order.

[0081] As described above, the valve stem 40, the valve element 50, the push-in base 51, the cam link 70, the central shaft 80, and the connecting arm 90 are arranged in the flow path F of the main body mechanism X in an assembled state. Then, the fixed base 60 is attached to the cylindrical main body 11 of the valve box 10 that constitutes the main body mechanism X. Specifically, the fixed base 60 is placed on the base 12 so that the cylindrical protrusion 62 of the fixed base 60 is inserted into the through-hole 121 of the base 12 of the valve box 10, and is fixed with a bolt (not shown). At this time, the end of the central shaft 80 is inserted into and fitted into the fitting recess 63 provided on the tip surface of the cylindrical protrusion 62 of the fixed base 60.

[0082] The valve stem 40 is inserted into the insertion hole 64 of the fixed base 60 and attached to complete the opening / closing mechanism Y. The butterfly valve 1 is then completed by assembling the opening / closing mechanism Y to the main body mechanism X as described above. Note that, by attaching a fall-out prevention ring 66 to the upper HU 60 for the valve stem 40 inserted into the insertion hole 64 of the fixed base 60 and by attaching a support metal fitting 65 to the fixed base 60 of the lower HD, it is possible to prevent the valve stem 40 from being accidentally pulled out.

[0083] The operation of the opening and closing mechanism Y that is assembled to the valve box 10 to form the butterfly valve 1 in this manner will be described below. In the open state shown in Figures 10(a) and (b), the valve rod 40 is rotated counterclockwise in a plan view, and the valve body 50 is positioned to the right of the flow path F inside the main body mechanism X when viewed from the front.

[0084] At this time, the pillar portion 71 of the L-shaped arm portion 72, which is the driving body of the four-bar link mechanism FL, faces the rear side DB relative to the valve stem center of the valve stem 40, and the first movable arm 92, which is the passive body in the four-bar link mechanism FL, and the second movable arm 93 are connected at a connection angle θ.

[0085] Furthermore, since the first movable arm 92 and the second movable arm 93, which are connected at a connection angle θ, have a horizontal portion 53 connected at the rotation center R0 and the second connection portion R2, which is arranged in a direction perpendicular to the right side of the flow path F, as described above, the valve body 50 attached to the fixed surface portion 52 of the push-in base 51 is positioned to the right side of the flow path F inside the main mechanism X when viewed from the front.

[0086] As described above, when the first movable arm 92, which is the passive body in the four-bar link mechanism FL, and the second movable arm 93 are connected at a connection angle θ, the central axis 80 that forms the rotation center R0 is positioned in its normal position, which is on the side of the connecting hole 55 in the oval rotation center hole 56 provided in the horizontal section 53.

[0087] In this way, the central axis 80, which serves as the rotation center R0, is positioned in the normal position of the rotation center hole 56, and the first movable arm 92 and the second movable arm 93, which serve as passive bodies in the four-bar linkage FL, are connected at the connection angle θ in a stable state. Therefore, as shown in Figures 10(c) to 10(f), this state is maintained until the valve stem 40 rotates clockwise to a predetermined angle of 90 degrees in a plan view, and the push-in base 51, to which the valve disc 50 is attached, rotates around the rotation center R0 as the valve stem 40 rotates. When the valve stem 40 rotates clockwise to the predetermined angle of 90 degrees, the push-in base 51 rotates around the rotation center R0, and the horizontal portion 53 is positioned along the flow path F, and the valve disc 50 attached to the fixed surface portion 52 is positioned opposite the flow path F and the seat ring 20 attached to the tubular main body portion 11 of the valve box 10 in the main body mechanism X (see Figures 10(e) and 10(f)).

[0088] When the valve stem 40 is further rotated clockwise beyond the predetermined angle of 90 degrees, the valve body 50, which was facing the seat ring 20 and the flow path F, comes into contact with some part of the seat ring 20, and due to the contact load between the seat ring 20 and the valve body 50, the rotation of the push-in base 51 around the rotation center R0 that accompanies the rotation of the valve stem 40 is restricted.

[0089] In a state where the rotation of the push-in base 51 around the rotation center R0 accompanying the rotation of the valve stem 40 is restricted, further rotation of the valve stem 40 causes the L-shaped arm portion 72, which is the driving body of the four-bar link mechanism FL, to rotate around the valve stem center. When the L-shaped arm portion 72, which is the driving body of the four-bar link mechanism FL, rotates, the driving arm 91, which is the intermediate body, causes the first movable arm 92, which is the passive body, to rotate around the rotation center R0.

[0090] In this way, further rotation of the valve stem 40 is transmitted from the L-shaped arm portion 72 in the four-bar link mechanism FL and output as rotation of the first movable arm 92, and the connection angle between the first movable arm 92 and the second movable arm 93, which are rotatably connected at the first connection portion R1, is deformed so as to widen.

[0091] When the connection angle between the first movable arm 92 and the second movable arm 93, which are rotatably connected at the first connecting portion R1, is deformed so as to widen, the distance between the rotation center R0, which is the center of the central shaft 80 inserted through the rotation center hole 921 of the first movable arm 92, and the second connecting portion R2 at the connecting hole 932 of the second movable arm 93 also tends to widen. However, the connecting holes 55 and 932 that constitute the second connecting portion R2 are circular and cannot move, so the central shaft 80 that constitutes the rotation center R0 moves toward the valve closed position in the rotation center hole 56, which is formed in an oval shape.

[0092] However, because the central axis 80 is fixed in the main body mechanism X, the push-in base 51, which has a horizontal portion 53 with a rotation center hole 56, moves toward the front side DF relative to the central axis 80. When the push-in base 51 moves toward the front side DF relative to the main body mechanism X, the valve element 50 attached to the fixed surface portion 52 of the push-in base 51 moves along the flow path F toward the seat ring 20 attached to the tube main body portion 11 of the valve box 10 in the main body mechanism X.

[0093] Furthermore, as described above, when the valve rod 40 rotates, the rotation is transmitted from the L-shaped arm portion 72 in the four-bar link mechanism FL and output as rotation of the first movable arm 92, and the connection angle between the first movable arm 92 and the second movable arm 93, which are rotatably connected at the first connection portion R1, further widens, and the first movable arm 92 and the second movable arm 93 become linear. In other words, the connection angle between the first movable arm 92 and the second movable arm 93 at the first connection portion R1 becomes 180 degrees, and the push-in base 51 to which the valve body 50 is attached moves as far as possible toward the front side DF with respect to the central axis 80 that forms the rotation center R0, and the valve body 50 can be in close contact with the seat ring 20, achieving a closed valve state (see Figures 10(g), (h) and Figure 11(b)).

[0094] In order to open the valve from the closed state in which the valve body 50 is in close contact with the seat ring 20, the valve stem 40 can be rotated counterclockwise in a plan view, thereby performing the above-described operations in the reverse order to open the valve.

[0095] As described above, the butterfly valve 1 includes the valve body 10 having the tubular flow path F, the valve stem 40 rotatably mounted on the valve body 10, the valve disc 50 that is rotated by the valve stem 40 to open and close the flow path F, and the seat ring 20 mounted between the valve body 10 and the valve disc 50. Between the valve stem 40 and the valve disc 50, an opening / closing mechanism Y is provided. The opening / closing mechanism Y rotates the valve disc 50 as the valve stem 40 rotates from the valve open position to a predetermined angle (90 degrees), and moves the valve disc 50 so as to come into close contact with the seat ring 20 when the valve stem 40 rotates beyond the predetermined angle (90 degrees). The opening / closing mechanism Y includes a four-bar link mechanism FL that rotates as the valve stem 40 rotates, and a second movable arm 93 rotatably connected to each of the four-bar link mechanism FL and the valve disc 50. The connection portion where the second movable arm 93 and the four-bar link mechanism FL are rotatably connected is referred to as a first connection portion R1. In addition, the connection portion where the second movable arm 93 and the valve body 50 are rotatably connected is designated as the second connection portion R2, and in the four-bar link mechanism FL, the distance between the rotation center R0 of the four-bar link mechanism FL and the first connection portion R1 is designated as the first arm length L1, and in the second movable arm 93, the distance between the first connection portion R1 and the second connection portion R2 is designated as the second arm length L2, and the closed-valve length L3 connecting the second connection portion R2 and the rotation center R0 in a state where the valve body 50 has moved to be in close contact with the seat ring 20 is less than the sum of the first arm length L1 and the second arm length L2, and when the valve rod 40 rotates beyond a predetermined angle (90 degrees), the connection angle θ between the four-bar link mechanism FL and the second movable arm 93 at the first connection portion R1 changes, and the valve body 50 moves along the flow path F to be in close contact with the seat ring 20, thereby obtaining a stable, high compression surface pressure.

[0096] In more detail, the opening and closing mechanism Y in the butterfly valve 1 rotates the valve element 50 using the valve stem 40, causing the valve element 50 to abut against the seat ring 20 to open and close the flow path F in the valve box 10. As the valve stem 40 rotates from the open position to a predetermined angle (90 degrees), the valve element 50 also rotates, and as the valve stem 40 rotates beyond the predetermined angle (90 degrees), the valve element 50 can be moved so that it is in close contact with the seat ring 20.

[0097] The opening / closing mechanism Y is provided with a four-bar link mechanism FL that rotates with the rotation of the valve stem 40, and a second movable arm 93 rotatably connected to each of the four-bar link mechanism FL and the valve body 50. In the four-bar link mechanism FL, a first arm length L1 is the distance between the rotation center R0 of the four-bar link mechanism FL and a first connecting part R1 at which the second movable arm 93 and the four-bar link mechanism FL are rotatably connected, and in the second movable arm 93, a first arm length L2 is the distance between the second connecting part R2 at which the second movable arm 93 and the valve body 50 are rotatably connected and the first connecting part R1. and the second arm length L2, which is the distance between the first and second arm lengths L1 and L2, is equal to or greater than the closed-state length L3 connecting the second connecting part R2 and the rotation center R0 when the valve disc 50 has moved to be in close contact with the seat ring 20. When the valve stem 40 rotates beyond a predetermined angle (90 degrees), the connecting angle θ between the four-bar linkage FL at the first connecting part R1 and the second movable arm 93 changes, causing the valve disc 50 to move along the flow path F to be in close contact with the seat ring 20. Therefore, in the closed state, the valve disc 50 and the seat ring 20 are in close contact with each other under high compressive surface pressure. Therefore, even when blocking the flow of a fluid with a small molecular size or an extremely low temperature fluid such as cryogenic fluid, the fluid does not leak out from between the seat ring 20 and the valve disc 50, and the flow path F can be reliably blocked.

[0098] Furthermore, when the valve stem 40 is rotated beyond a predetermined angle (90 degrees), the connection angle θ becomes wider than the connection angle θ when the valve stem 40 is rotated up to the predetermined angle (90 degrees), and the length connecting the second connection part R2 and the rotation center R0 becomes longer, thereby forming a so-called crank mechanism.When the valve stem 40 is rotated beyond the predetermined angle (90 degrees), the valve body 50 is moved along the flow path F so that it is in close contact with the seat ring 20, thereby forming a closed valve state in which the valve body 50 and the seat ring 20 are in close contact with each other under high compression surface pressure.

[0099] Furthermore, in the closed valve state where the valve body 50 and the seat ring 20 are in close contact with each other, the rotation center R0, the first connecting portion R1, and the second connecting portion R2 are aligned in a straight line. Therefore, even if an external force acts on the valve body 50 from the fluid in the valve opening direction in the closed valve state where the valve body 50 and the seat ring 20 are in close contact with each other under high compressive surface pressure, the rotation center R0, the first connecting portion R1, and the second connecting portion R2 are aligned in a straight line, and the closed valve state can be reliably maintained against the external force.

[0100] In addition, a horizontal portion 53 is provided to restrict the direction of movement of the valve element 50 along the flow path F, so that when the valve rod 40 rotates beyond a predetermined angle (90 degrees), the direction of movement of the valve element 50 moving toward the seat ring 20 can be restricted to a direction along the flow path F, and the valve element 50 and the seat ring 20 can be placed in close contact with each other under high compression surface pressure to form a closed valve state.

[0101] Furthermore, the horizontal portion 53 connects the rotation center R0 and the second connecting portion R2 and is configured to be movable relative to the rotation center R0, so that the direction of movement of the valve body 50 moving toward the seat ring 20 due to rotation of the valve stem 40 exceeding a predetermined angle (90 degrees) can be regulated with a simple structure.

[0102] Furthermore, the four-bar link mechanism FL has fixed positions for the valve stem 40 and the center of rotation R0, and is provided with an L-shaped arm portion 72 that is connected to the valve stem 40 and rotates together with the valve stem 40, a first movable arm 92 that connects the center of rotation R0 and the first connecting portion R1, and a drive arm 91 that connects the L-shaped arm portion 72 and the first movable arm 92. Therefore, with a small rotational force of the valve stem 40, the valve body 50 and the seat ring 20 are brought into close contact with each other under high compression surface pressure.

[0103] More specifically, a large rotational force is required to directly apply the rotational force of the valve stem 40 to bring the valve disc 50 and the seat ring 20 into close contact with each other under high compressive surface pressure. In contrast, the four-bar link mechanism FL fixes the positions of the valve stem 40 and the center of rotation R0, and includes an L-shaped arm 72 connected to the valve stem 40 and rotating with it, a first movable arm 92 connecting the center of rotation R0 and the first connecting part R1, and a drive arm 91 connecting the L-shaped arm 72 and the first movable arm 92. This allows the valve disc 50 and the seat ring 20 to be brought into close contact with each other under high compressive surface pressure with a smaller rotational force than when the rotational force of the valve stem 40 is directly applied.

[0104] In the above description, the rotation of the valve stem 40 is transmitted to the push-in base 51 to which the valve disc 50 is attached by the four-bar link mechanism FL and the second movable arm 93, causing the valve stem 40 to rotate around the rotation center R0 formed by the central axis 80 and move along the depth direction D. However, as shown in Fig. 12, the valve stem center may be configured to coincide with the rotation center R0 by using a first movable arm 92a and a second movable arm 93a that function as a driving body and a driven body. Fig. 12 is an explanatory diagram of an opening / closing mechanism Ya of another embodiment.

[0105] 12(a) is a schematic diagram of the opening / closing mechanism Ya in an open state, FIG. 12(b) is a schematic diagram of the opening / closing mechanism Ya in a 45-degree rotated state where the valve stem 40 is rotated 45 degrees clockwise, FIG. 12(c) is a schematic diagram of the opening / closing mechanism Ya in a 90-degree rotated state where the valve stem 40 is rotated 90 degrees, which is a predetermined angle, and FIG. 12(d) is a schematic diagram of the opening / closing mechanism Ya in a closed state where the valve stem 40 is rotated beyond the predetermined angle. Note that the main body mechanism X is not shown in FIG. 12. In the following description of the opening and closing mechanism Ya, the same components as those in the opening and closing mechanism Y described above will be assigned the same reference numerals and the description thereof will be omitted.

[0106] In the above description of the opening / closing mechanism Y, the rotation of the valve stem 40 is transmitted from the L-shaped arm portion 72, which is the driving body of the four-bar link mechanism FL, via the drive arm 91, which is the intermediate body, to rotate the first movable arm 92, which is the passive body, and then to the second movable arm 93, which is rotatably connected to the first movable arm 92 at the first connecting portion R1, thereby rotating the pushing base 51 around the rotation center R0. In contrast, the second movable arm 93a in the opening / closing mechanism Ya has the same function as the above-mentioned second movable arm 93, but the first movable arm 92a is configured to function as both the driving body and the passive body.

[0107] Specifically, the opening / closing mechanism Ya does not have the cam link 70 or drive arm 91 of the opening / closing mechanism Y, but has a valve stem 40 attached to one end of a first movable arm 92a, and a first connecting part R1a rotatably connected to a second movable arm 93a at the opposite end of the first movable arm 92a. One end of the second movable arm 93a, which is functionally similar to the above-mentioned second movable arm 93, is rotatably connected to the above-mentioned first movable arm 92a to form the first connecting part R1a, and the other end is rotatably connected to the push-in base 51 to form the second connecting part R2a. The rotation center R0a of the opening / closing mechanism Ya configured in this manner coincides with the valve stem center, which is the rotation center of the valve stem 40.

[0108] 12, the first connecting portion R1a and the second connecting portion R2a are arranged in this order from the rotation center R0a toward the valve body 50. In other words, the rotation center R0a is arranged at a position farthest from the valve body 50 with respect to the connecting portions R1a and R2a.

[0109] In addition, the first arm length L1a, which is the length connecting the rotation center R0a of the first movable arm 92a and the center of the first connecting portion R1a, and the second arm length L2a, which is the length connecting the center of the first connecting portion R1a of the second movable arm 93a and the center of the second connecting portion R2a, are the same length.

[0110] In addition, in the opening / closing mechanism Ya, the sum of the first arm length L1a of the first movable arm 92a and the second arm length L2a of the second movable arm 93a is formed to be the same length as or slightly longer than the closed-valve state length L3a between the rotation center R0a and the second connecting portion R2a in the closed-valve state. Therefore, in the valve open state, the first movable arm 92a and the second movable arm 93a are connected to each other in a bent manner at the first connecting portion R1a, and the connecting angle θa at the first connecting portion R1a becomes narrow.

[0111] In the opening / closing mechanism Ya configured in this manner, when the valve rod 40 is rotated clockwise in a plan view from the open valve state shown in Figure 12(a), the push-in base 51 also rotates in conjunction with the rotation of the valve rod 40, as shown in Figures 12(b) and (c), while maintaining the connected state at the connection angle θa.

[0112] 12(c), when the valve stem 40 is further rotated clockwise in a plan view after being rotated 90 degrees, which is the predetermined angle, from the valve open position, the contact load of the valve disc 50 and the seat ring 20 restricts rotation of the valve disc 50 about the rotation center R0a. When rotation of the valve disc 50 about the rotation center R0a is restricted, the first movable arm 92a and the second movable arm 93a, which rotate along with the valve stem 40, deform so that the connection angle of the first connecting portion R1a increases, and the first movable arm 92a and the second movable arm 93a become aligned in a straight line. In other words, the rotation center R0a, the first connecting portion R1a, and the second connecting portion R2a are aligned in a straight line along the flow path F, and the second connecting portion R2a is spaced apart from the rotation center R0a. When the second connecting portion R2a moves away from the rotation center R0a, the valve element 50 moves toward the front side DF along the flow path F so as to come into close contact with the seat ring 20, thereby achieving a closed valve state.

[0113] In this way, the first movable arm 92a of the butterfly valve is connected to the valve stem 40 and the first connecting portion R1a and rotates together with the valve stem 40, so that the rotational force of the valve stem 40 can be used to move the valve body 50 along the flow path F with the first movable arm 92a having a simple structure.

[0114] In the above description of the opening / closing mechanism Ya, the opening / closing mechanism Ya is configured with a first movable arm 92a and a second movable arm 93a functioning as a driving body and a passive body, and the stem center and the rotation center R0a are aligned. When the stem 40 rotates beyond a predetermined angle, the rotation center R0a, the first connecting portion R1a, and the second connecting portion R2a are aligned in a straight line along the flow path F. When the second connecting portion R2a moves away from the rotation center R0a, the disc 50 moves toward the front DF along the flow path F so as to come into close contact with the seat ring 20, thereby achieving the closed valve state. In contrast, as shown in FIG. 13 , the opening / closing mechanism Ya may be configured with a first movable arm 92b and a second movable arm 93b functioning as a driving body and a passive body, and the stem center and the rotation center R0b are aligned. When the stem 40 rotates beyond a predetermined angle, the second connecting portion R2a moves toward the rotation center R0a, thereby moving the disc 50 toward the front DF along the flow path F so as to come into close contact with the seat ring 20, thereby achieving the closed valve state. FIG. 13 is an explanatory diagram of an opening / closing mechanism Yb according to another embodiment.

[0115] 13(a) is a schematic diagram of the opening / closing mechanism Yb in an open state, FIG. 13(a) is a schematic diagram of the opening / closing mechanism Yb in a 45-degree rotated state where the valve stem 40 is rotated 45 degrees clockwise, FIG. 13(c) is a schematic diagram of the opening / closing mechanism Yb in a 90-degree rotated state where the valve stem 40 is rotated 90 degrees, which is a predetermined angle, and FIG. 13(d) is a schematic diagram of the opening / closing mechanism Yb in a closed state where the valve stem 40 is rotated beyond the predetermined angle. Note that the main body mechanism X is not shown in FIG. 13. In the following description of the opening and closing mechanism Yb, the same components as those in the opening and closing mechanisms Y and Ya described above will be assigned the same reference numerals and description thereof will be omitted.

[0116] The opening / closing mechanism Yb is similar to the opening / closing mechanism Ya in that the second movable arm 93b has the same function as the second movable arm 93 described above, but the first movable arm 92b is configured to function as both a driving body and a passive body.

[0117] Specifically, the opening / closing mechanism Yb does not have the cam link 70 or drive arm 91 of the opening / closing mechanism Y, but has a valve stem 40 attached to one end of a first movable arm 92b, and a first connecting part R1b rotatably connected to a second movable arm 93b at the opposite end of the first movable arm 92b. One end of the second movable arm 93b, which is functionally similar to the above-mentioned second movable arm 93, is rotatably connected to the above-mentioned first movable arm 92b to form the first connecting part R1b, and the other end is rotatably connected to the push-in base 51 to form the second connecting part R2b. The rotation center R0b of the opening / closing mechanism Yb configured in this manner coincides with the valve stem center, which is the rotation center of the valve stem 40.

[0118] Unlike the above-mentioned opening / closing mechanism Ya, the opening / closing mechanism Yb is arranged such that the rotation center R0b is positioned closest to the valve body 50, and the first connecting portion R1b and the second connecting portion R2b are arranged in this order so as to be farther away from the rotation center R0b than the valve body 50, as shown in Figure 13.

[0119] Also, similar to the opening / closing mechanism Ya, the first arm length L1b, which is the length connecting the rotation center R0b of the first movable arm 92b and the center of the first connecting portion R1b, and the second arm length L2b, which is the length connecting the center of the first connecting portion R1b of the second movable arm 93b and the center of the second connecting portion R2b, are the same length.

[0120] In addition, in the opening / closing mechanism Yb, the sum of the first arm length L1b of the first movable arm 92b and the second arm length L2b of the second movable arm 93b is longer than the closed-valve state length L3b between the rotation center R0b and the second connecting portion R2b in the open valve state.

[0121] Furthermore, unlike the opening / closing mechanism Ya in which the first movable arm 92b and the second movable arm 93b are connected at a large bend at the first connecting portion R1b in the open valve state, in the opening / closing mechanism Yb, the first movable arm 92b and the second movable arm 93b are aligned in a straight line, that is, the rotation center R0b, the first connecting portion R1b and the second connecting portion R2b are arranged in a straight line along the flow path F.

[0122] 13(b) and 13(c), when the valve stem 40 of the opening / closing mechanism Yb configured in this manner is rotated clockwise in a plan view from the open state shown in Fig. 13(a), the push-in base 51 also rotates in conjunction with the rotation of the valve stem 40, while maintaining the state in which the rotation center R0b, the first connecting portion R1b, and the second connecting portion R2b are aligned in a straight line along the flow path F. In other words, the push-in base 51 also rotates in conjunction with the rotation of the valve stem 40, while maintaining the state in which the second connecting portion R2b is separated from the rotation center R0b.

[0123] 13(c), when the valve stem 40 is further rotated clockwise in plan view from the state where it has been rotated 90 degrees, which is the predetermined angle, from the valve open position, the rotation of the valve stem 40 around the rotation center R0b is restricted by the contact load of the valve disc 50 contacting the seat ring 20. When the rotation of the valve disc 50 around the rotation center R0b is restricted, the first movable arm 92b and the second movable arm 93b, which rotate together with the valve stem 40, bend at the first connecting portion R1a, and the connecting angle θb at the first connecting portion R1b becomes narrower.

[0124] In this way, the first connecting portion R1b is deformed so that the connecting angle θb becomes narrower, and the first movable arm 92b and the second movable arm 93b are bent, so that the second connecting portion R2b approaches the rotation center R0b located on the side of the valve body 50. When the second connecting portion R2b approaches the rotation center R0b, the valve body 50 moves toward the front side DF along the flow path F so as to come into close contact with the seat ring 20, thereby achieving a closed valve state.

[0125] In this way, the first movable arm 92b of the butterfly valve is connected to the valve stem 40 and the first connecting portion R1b and rotates together with the valve stem 40, so that the rotational force of the valve stem 40 can be used to move the valve body 50 along the flow path F with the first movable arm 92b having a simple structure.

[0126] In detail, when the valve rod 40 rotates beyond a predetermined angle (90 degrees), the connection angle θb at the first connection part R1b becomes narrower than the connection angle θb at the first connection part R1b when the valve rod 40 rotates up to the predetermined angle (90 degrees), and the length connecting the second connection part R2b and the rotation center R0b becomes shorter, thereby moving the valve body 50 along the flow path F so that it is in close contact with the seat ring 20, and a closed valve state can be achieved in which the valve body 50 and the seat ring 20 are in close contact with each other under high compression surface pressure.

[0127] As described above, in correspondence between the configuration of the present invention and the above-mentioned embodiment, the flow path of the present invention corresponds to the flow path F, Similarly, The valve box corresponds to valve box 10, The valve stem corresponds to the valve stem 40; The valve element corresponds to the valve element 50, The seat ring is compatible with seat ring 20. The rotational movement conversion mechanism corresponds to the opening and closing mechanisms Y, Ya, and Yb. The rotating part corresponds to the four-bar link mechanism FL and the first movable arms 92a and 92b. The rotary connector corresponds to the second movable arms 93, 93a, and 93b. The first connecting portions correspond to the first connecting portions R1, R1a, and R1b, The second connecting portions correspond to the second connecting portions R2, R2a, and R2b, The rotation centers correspond to rotation centers R0, R0a, and R0b. The length of the rotating part corresponds to the length of the first arm L1, L1a, L1b, The length of the connecting part corresponds to the second arm length L2, L2a, L2b, The straight line lengths correspond to the closed valve lengths L3, L2a, and L2b. The specified angle corresponds to 90 degrees, The butterfly valve corresponds to butterfly valve 1, 1a, 1b, The connection angles correspond to the connection angles θ, θa, and θb. The movement direction restricting means corresponds to the horizontal portion 53, The driving body corresponds to the L-shaped arm part 72, The passive body corresponds to the first movable arm 92, The intermediate body corresponds to the drive arm 91, The four-bar link mechanism corresponds to the four-bar link mechanism FL, but is not limited to the above embodiment.

[0128] In the above description, the valve stem 40 is rotated clockwise to operate the opening / closing mechanisms Y, Ya, Yb, and the valve is changed from an open state to a closed state in which the valve element 50 and the seat ring 20 are in close contact with each other under high compressive surface pressure. However, the butterfly valves 1, 1a, 1b may also be configured to change from an open state to a closed state by rotating the valve stem 40 counterclockwise, for example.

[0129] Furthermore, in the four-bar link mechanism FL, the drive arm 91, which functions as an intermediate body, is rotatably connected to the first connecting part R1, which rotatably connects the first movable arm 92 and the second movable arm 93, which are passive bodies, but it may also be rotatably connected to the first movable arm 92 at a position different from the first connecting part R1.

[0130] Furthermore, although the above-described butterfly valves 1, 1a, and 1b are center-type butterfly valves, they may also be configured as primary eccentric butterfly valves or secondary eccentric butterfly valves. In the above description, the valve element 50 is moved along the flow path F to be in close contact with the seat ring 20. However, the valve element 50 may be configured to move in a direction intersecting the flow path F.

[0131] 1, 1a, 1b...Butterfly valve 10...Valve box 20...Seat ring 40...Valve stem 50...Valve body 53…Horizontal part 70…Camlink 72...L-shaped arm 91...Drive arm 92, 92a, 92b...First movable arm 93, 93a, 93b...Second movable arm F...flow path FL...4-section link mechanism L1, L1a, L1b...First arm length L2, L2a, L2b...Second arm length L3, L3a, L3b...Length in closed state R0, R0a, R0b...center of rotation R1, R1a, R1b…1st connection part R2, R2a, R2b…Second connection part Y, Ya, Yb...Opening and closing mechanism θ, θa, θb…Connection angle

Claims

1. a valve body having a tubular flow path; a valve stem rotatably mounted on the valve body; a valve body that is rotated by the valve stem and opens and closes the flow path; a seat ring provided between the valve body and the valve body, Between the valve stem and the valve body, a rotational movement conversion mechanism that rotates the valve disc as the valve stem rotates from the valve open position to a predetermined angle, and moves the valve disc so as to come into close contact with the seat ring when the valve stem rotates beyond the predetermined angle; The rotational movement conversion mechanism includes: a rotating portion that rotates in accordance with the rotation of the valve stem; a rotary connector rotatably connected to the rotary portion and the valve body, a connecting portion where the rotary connecting body and the rotating portion are rotatably connected to each other is defined as a first connecting portion, and a connecting portion where the rotary connecting body and the valve body are rotatably connected to each other is defined as a second connecting portion, In the rotating portion, a distance between a rotation center of the rotating portion and the first connecting portion is defined as a rotating portion length, In the rotary connecting body, a distance between the first connecting portion and the second connecting portion is defined as a connecting length, a straight line length connecting the second connecting portion and the rotation center in a state where the valve element has moved so as to be in close contact with the seat ring is equal to or less than a sum of the rotation length and the connecting portion length, When the valve stem rotates beyond the predetermined angle, the connection angle between the rotating portion and the rotary connection body in the first connection portion changes, and the valve element moves along the flow path so as to come into close contact with the seat ring. Butterfly valve.

2. Rotation of the valve stem beyond the predetermined angle The connecting angle becomes wider than the connecting angle when the valve stem rotates up to the predetermined angle, and the length connecting the second connecting portion and the rotation center becomes longer.

2. The butterfly valve of claim 1.

3. In a valve-closed state in which the valve body and the seat ring are in close contact with each other, The rotation center, the first connecting portion, and the second connecting portion are aligned in a straight line.

3. The butterfly valve of claim 2.

4. A movement direction restricting means is provided for restricting the movement direction of the valve body along the flow path.

3. The butterfly valve of claim 2.

5. The movement direction regulating means The rotation center and the second connecting portion are connected together, configured to be movable relative to the rotation center 5. The butterfly valve according to claim 4.

6. The rotating part is The positions of the valve stem and the rotation center are fixed, and a driving body connected to the valve stem and rotating with the valve stem; a passive body that connects the rotation center and the first connecting portion; and A four-bar link mechanism is provided with an intermediate body that connects the driving body and the passive body.

6. The butterfly valve according to claim 5.

7. The rotating part is a driving body that is connected to the valve stem and the first connecting portion and rotates together with the valve stem; 3. The butterfly valve of claim 2.

8. Rotation of the valve stem beyond the predetermined angle The connecting angle becomes narrower than the connecting angle when the valve stem rotates up to the predetermined angle, and the length connecting the second connecting portion and the rotation center becomes shorter.

2. The butterfly valve of claim 1.

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