Butterfly valve

Abstract

The purpose of the present invention is to provide a butterfly valve capable of obtaining consistent high compression surface pressure.　This butterfly valve is provided with a rotational movement conversion mechanism MD whereby a valve body 50 rotates along with the rotation of a valve rod 40 from a valve opening position to 90 degrees, and rotation of the valve rod 40 past 90 degrees causes the valve body 50 to move from an axial center along a flow path F so as to make intimate contact with a seat ring 20. The rotational movement conversion mechanism MD is provided with a cam 80 having a circular arc-shaped portion 84, which is the major diameter, and a cam groove 54 into which the cam 80 fits. Rotation of the valve rod 40 past 135 degrees causes the circular arc-shaped portion 84 to escape from a large circular arc-shaped portion 543 of the cam groove 54 and push a linear portion 542, causing the valve body 50 to move from the axial center along the flow path F so as to come into in close contact with the seat ring 20.

Description

Butterfly Valve

[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.

[0002] Conventionally, as shown in Patent Document 1, butterfly valves have been used which include 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 adjust the flow rate by opening and closing the flow of fluid, or switch 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.

[0004] Japanese Patent Application Laid-Open No. 2003-185047

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

[0006] This invention provides 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 as the valve stem rotates from a valve open position to a predetermined angle, and which moves the valve disc so as to come into close contact with the seat ring when the valve stem rotates beyond the predetermined angle, and the rotational movement conversion mechanism is provided with a convex portion having a diameter longer than that of other portions in the circumferential direction. a cam body provided on either the valve stem or the valve disc, and a cam groove provided on the other of the valve stem or the valve disc, into which the cam body fits, the cam groove having a recess corresponding to the convex portion and a pushing surface continuous with the recess and pushed in by the convex portion, wherein when the valve stem rotates beyond the predetermined angle, the convex portion escapes from the recess and pushes in the pushing surface, moving the valve disc from the axis of the valve stem along the flow path so as 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 may also be called a valve main body, housing, or body. The seat ring may also be called a valve seat. The rotational movement conversion mechanism may move in the direction of fluid flow or in a direction intersecting the flow direction, as long as it can move the valve disc so as to closely contact the seat ring.

[0008] The present invention provides a stable, high compression surface pressure. More specifically, the butterfly valve has a valve stem that rotates the valve disc, bringing the valve disc into contact with the seat ring to open and close the flow path in the valve body. The rotation-movement conversion mechanism of the butterfly valve rotates the valve disc as the valve stem rotates from the valve open position to a predetermined angle, and the valve disc is moved to come into close contact with the seat ring when the valve stem rotates beyond the predetermined angle.

[0009] The rotational movement conversion mechanism has a convex portion having a longer diameter in the circumferential direction than the other portion, and is equipped with a cam body provided on either the valve stem or the valve disc, and a cam groove provided on the other of the valve stem or the valve disc into which the cam body fits, the cam groove having a concave portion corresponding to the convex portion, and a pushing surface continuous with the concave portion and pushed into by the convex portion, so that when the valve stem rotates beyond the predetermined angle, the convex portion escapes from the concave portion and pushes into the pushing surface, moving the valve disc so as to come into close contact with the seat ring.

[0010] Therefore, in the closed state, the valve disc and the seat ring are in close contact with each other under high compressive pressure, so that even when blocking the flow of a fluid with a small molecular size or an extremely low temperature fluid, such as a cryogenic fluid, the fluid does not leak out from between the seat ring and the valve disc, and the flow path can be reliably blocked.

[0011] In one aspect of the present invention, a rotation restriction mechanism may be provided that allows the valve element to rotate from the open position of the valve stem up to the predetermined angle, restricts rotation of the valve element associated with rotation of the valve stem beyond the predetermined angle, and allows movement of the valve element in a direction that brings it into close contact with the seat ring.

[0012] According to this invention, the rotation restriction mechanism restricts the rotation of the valve body that accompanies rotation of the valve stem beyond the predetermined angle, while in the closed valve state, the rotation movement conversion mechanism moves the valve body in a direction that brings it into close contact with the seat ring, thereby reliably blocking the flow path.

[0013] In another aspect of the present invention, the rotational movement conversion mechanism and the rotation restriction mechanism may be provided on both sides of the valve body in the axial direction along the axis, and a transmission member for transmitting the rotational force of the valve rod may be provided to the rotational movement conversion mechanism and the rotation restriction mechanism on the side to which the rotational force is not input from the valve rod, of the rotational movement conversion mechanism and the rotation restriction mechanism provided on both sides of the valve body in the axial direction.

[0014] According to this invention, the transmission member can transmit the rotational force of the valve stem to the rotational movement conversion mechanism and the rotation restricting mechanism provided on both sides of the valve disc in the axial direction, which are the rotational movement conversion mechanism and the rotation restricting mechanism on the side to which the rotational force is not input from the valve stem. Therefore, while the rotational movement conversion mechanism and the rotation restricting mechanism provided on both sides in the axial direction restrict rotation of the valve disc associated with rotation of the valve stem exceeding the predetermined angle, in the valve closed state, the rotational movement conversion mechanism can move the valve disc in a direction to come into close contact with the seat ring, thereby more reliably blocking the flow path.

[0015] In one aspect of the present invention, a portion of the transmission member may be provided with an offset portion that is offset in a predetermined direction from the axis to suppress a decrease in the flow path area in the open valve state. With this invention, the rotational movement conversion mechanism can move the valve disc in a direction in which it comes into close contact with the seat ring in the closed valve state, thereby more reliably blocking the flow path without reducing the flow capacity in the open valve state.

[0016] Specifically, the axis, which is the center of rotation of the rotating valve stem and the valve disc, is positioned so as to cross the tubular flow path blocked by the valve disc in the closed position. Therefore, if the transmission member, which transmits the rotational force of the valve stem to the rotational movement conversion mechanism and the rotation restriction mechanism on either side of the valve disc in the axial direction, that does not receive the rotational force from the valve stem, is positioned at the axis, the transmission member crosses the flow path, reducing the flow path area in the open state and reducing flow capacity in the open state. In response to this, a portion of the transmission member is provided with a biased portion that is shifted in a predetermined direction from the axis, thereby suppressing the reduction in flow path area in the open state. Therefore, while suppressing the reduction in flow capacity caused by the transmission member in the open state, the rotational movement conversion mechanism moves the valve disc in a direction that makes contact with the seat ring in the closed state, thereby more reliably blocking the flow path.

[0017] In another aspect of the present invention, an over-rotation prevention unit may be provided to prevent the valve stem from rotating excessively from at least one of the valve closed position and the valve open position, thereby preventing a load from acting on the valve stem, the valve disc, or the seat ring due to excessive rotation of the valve stem.

[0018] In another aspect of the present invention, the valve stem may be rotated a predetermined angle, causing the valve disc to contact the seat ring and move due to a rotational load. With this invention, the valve disc can be moved in a direction that brings it into close contact with the seat ring in the closed state, reliably blocking the flow path, while restricting rotation of the valve disc that occurs when the valve stem rotates beyond the predetermined angle, without providing a rotation restriction mechanism. Therefore, the butterfly valve can be configured with a simpler structure than when a rotation restriction mechanism is provided.

[0019] The present invention also provides a valve body having a tubular flow path, a valve stem rotatably provided 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 provided between the valve body and the valve disc, wherein 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 which moves the valve disc so as to closely contact the seat ring when the valve stem rotates beyond the predetermined angle, the direction in which the rotational movement conversion mechanism moves the valve disc so as to closely contact the seat ring is defined as a movement direction, and the opposite direction is defined as a counter-movement direction, and the rotational movement conversion mechanism is provided between a cam body provided on either the valve stem or the valve disc, and a cam body provided on either the valve stem or the valve disc. and a cam groove provided on one side of the valve stem and into which the cam body fits, the cam groove having abutment portions spaced a predetermined distance apart in the movement direction, the cam body having at least two arc-shaped portions that are arc-shaped about an eccentric center that is eccentric with respect to an axial center that is the center of rotation of the valve stem, the two arc-shaped portions being arranged in opposing directions across the eccentric center, and the length of an imaginary line connecting the two arc-shaped portions that passes through the eccentric center is set to be equal to the predetermined distance, and when the valve stem rotates beyond the predetermined angle, the abutment portions arranged at the predetermined distance apart in the cam groove come into contact with the two arc-shaped portions, and the valve body moves from the axial center along the flow path so as to be in close contact with the seat ring.

[0020] 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 may also be called a valve main body, housing, or body. The seat ring may also be called a valve seat. The rotational movement conversion mechanism may move in the direction of fluid flow or in a direction intersecting the flow direction, as long as it can move the valve disc so as to closely contact the seat ring.

[0021] The cam groove may have any shape in plan view as long as it has abutment portions spaced a predetermined distance apart in the movement direction and the cam body can be rotatably fitted in. The arc shape centered on the eccentric center includes various curved shapes that protrude in a predetermined direction in plan view, such as a circular arc, an elliptical arc, or an oblong arc, and may have, for example, an inflection point.

[0022] The contacted portion may be in surface contact with the arc-shaped portion, or may be in line contact or point contact. The arc-shaped portion and the contacted portion may be in direct contact, or may be in contact via another member, or may have a small gap equivalent to a tolerance.

[0023] Furthermore, the above-mentioned cam body has at least two arc-shaped portions that are arc-shaped around an eccentric center that is eccentric with respect to the axial center that is the center of rotation of the valve rod, and the portions other than the arc-shaped portions may be linear, may be arc-shaped around the axial center, may be arc-shaped with a center different from the axial center and the eccentric center, or may be a combination of these.

[0024] Furthermore, the at least two arc-shaped portions centered on the eccentricity center may have different diameters or the same diameter. The imaginary line connecting the two arc-shaped portions and passing through the eccentricity center refers to a line that passes through the eccentricity center and connects points on the arc-shaped portions. The length of the imaginary line being equal to the predetermined interval may be the same, or may be slightly shorter by a tolerance.

[0025] The present invention provides a stable, high compression surface pressure. More specifically, the butterfly valve has a valve stem that rotates the valve disc, bringing the valve disc into contact with the seat ring to open and close the flow path in the valve body. The rotation-movement conversion mechanism of the butterfly valve rotates the valve disc as the valve stem rotates from the valve open position to a predetermined angle, and the valve disc is moved to come into close contact with the seat ring when the valve stem rotates beyond the predetermined angle.

[0026] The rotational movement conversion mechanism further comprises a cam body provided on either the valve stem or the valve disc, and a cam groove provided on the other of the valve stem or the valve disc. The cam groove fits the cam body and has abutment portions spaced a predetermined distance apart in the movement direction. The cam body comprises at least two arc-shaped portions, each arc-shaped about an eccentric center that is eccentric with respect to the axis that is the center of rotation of the valve stem. The two arc-shaped portions are arranged facing each other across the eccentric center, and the length of an imaginary line connecting the two arc-shaped portions and passing through the eccentric center is set to be equal to the predetermined distance.

[0027] In this manner, the rotational movement conversion mechanism, which is formed by the cam body and the cam groove, rotates the cam body relative to the cam groove as the valve stem rotates beyond the predetermined angle, and the abutment portions arranged at the predetermined interval in the cam groove abut against the two arc-shaped portions, and the valve body moves from the axis along the flow path so as to be in close contact with the seat ring.

[0028] Therefore, in the closed state, the valve disc and the seat ring are in close contact with each other under high compressive pressure, so that even when blocking the flow of a fluid with a small molecular size or an extremely low temperature fluid, such as a cryogenic fluid, the fluid does not leak out from between the seat ring and the valve disc, and the flow path can be reliably blocked.

[0029] Furthermore, the contact portions in the cam groove are arranged at the predetermined interval, and the two arc-shaped portions arranged facing each other across the eccentric center are set so that the length of an imaginary line connecting the two arc-shaped portions passing through the eccentric center is equal to the predetermined interval. Therefore, when the cam body rotates relative to the cam groove, no play occurs between the contact portions and the two arc-shaped portions arranged at the predetermined interval. Therefore, by rotating the valve stem beyond a predetermined angle, the valve disc can be moved stably from the axial center along the flow path so as to come into close contact with the seat ring.

[0030] In another aspect of the present invention, the two arc-shaped portions comprise a large diameter arc-shaped portion and a small diameter arc-shaped portion having different diameters, the large diameter arc-shaped portion and the small diameter arc-shaped portion are arranged facing each other across the eccentric center, and a length of an imaginary line connecting the large diameter arc-shaped portion and the small diameter arc-shaped portion, which passes through the eccentric center, is set to be equal to the predetermined distance, and when the valve rod rotates beyond the predetermined angle, the abutted portions arranged at the predetermined distance in the cam groove abut against the large diameter arc-shaped portion and the small diameter arc-shaped portion.

[0031] According to this invention, the valve element can be reliably brought into contact with the abutment portion even in various states depending on the eccentricity direction and amount of eccentricity of the eccentricity center relative to the axis, and can be moved from the axis along the flow path so as to be in close contact with the seat ring.

[0032] In another aspect of the present invention, when the valve stem is rotated by the predetermined angle, the eccentric center may be eccentric with respect to the axis in the counter-movement direction, the large diameter arc-shaped portion may be arranged on the side of the eccentric center in the movement direction, and the small diameter arc-shaped portion may be arranged on the side of the eccentric center in the counter-movement direction.

[0033] According to this invention, even if the eccentric center is eccentric in the counter-movement direction relative to the axial center after rotation by a predetermined angle, the large-diameter arc-shaped portion disposed on the side of the eccentric center in the movement direction and the small-diameter arc-shaped portion disposed on the side of the eccentric center in the counter-movement direction abut against the abutment portion, thereby moving the valve element from the axial center along the flow path so as to be in close contact with the seat ring. Furthermore, even during rotation in the opposite direction, the valve element abuts against the abutment portion and is in close contact with the seat ring can be moved away from the axial center along the flow path.

[0034] In another aspect of the present invention, when the valve stem is rotated by the predetermined angle, the eccentric center may be eccentric relative to the axis in a direction perpendicular to the direction of movement, the large diameter arc-shaped portion may be arranged on the side of the eccentric center in the counter-movement direction and opposite to the side on which the eccentric center is located, and the small diameter arc-shaped portion may be arranged on the side of the eccentric center in the direction of movement and on the side on which the eccentric center is located.

[0035] According to this invention, even if the eccentric center is eccentric with respect to the axis in a direction perpendicular to the direction of movement when rotated by a predetermined angle, the large-diameter arc-shaped portion, which is disposed on the side of the eccentric center in the counter-movement direction and opposite the side on which the eccentric center is located, and the small-diameter arc-shaped portion, which is disposed on the side of the eccentric center in the movement direction and on the side on which the eccentric center is located, abut against the abutment portion, thereby moving the valve element from the axis along the flow path so as to come into close contact with the seat ring. Furthermore, even during rotation in the opposite direction, the valve element abuts against the abutment portion and moves away from the seat ring along the flow path toward the axis.

[0036] In another aspect of the present invention, a rotation restriction mechanism may be provided that allows the disc to rotate from the valve open position of the valve stem to the predetermined angle, restricts the disc from rotating as the valve stem rotates beyond the predetermined angle, and allows the disc to move in a direction that brings the disc into close contact with the seat ring. This invention can achieve the same effects as those achieved by the rotation restriction mechanism described above.

[0037] In another aspect of the present invention, the abutment portion provided in the cam groove may be formed by a surface extending in a direction perpendicular to the movement direction, and the cam body may be provided with an open valve abutment surface that abuts against the abutment portion in an open valve state, and a closed valve abutment surface that abuts against the abutment portion in a closed valve state.

[0038] According to this invention, in the open state, the valve-opening contact surface of the cam body comes into face-to-face contact with the contacted portion formed by a surface extending in a direction perpendicular to the direction of movement, and in the closed state, the valve-closing contact surface of the cam body comes into face-to-face contact with the contacted portion formed by a surface extending in a direction perpendicular to the direction of movement, so that each state can be stably maintained. Furthermore, because the valve-opening contact surface and the valve-closing contact surface come into face-to-face contact with the contacted portion, excessive rotation of the valve stem beyond the face-to-face contact state can be prevented.

[0039] In another aspect of the present invention, the rotational movement conversion mechanism and the rotation restricting mechanism may be provided on both sides of the valve body in the axial direction along the axis, and a transmission member for transmitting the rotational force of the valve stem may be provided to the rotational movement conversion mechanism and the rotation restricting mechanism provided on both sides of the valve body in the axial direction, the rotational movement conversion mechanism and the rotation restricting mechanism being provided on the side to which the rotational force from the valve stem is not input. This invention can achieve the same effects as those achieved by the transmission member described above.

[0040] In another aspect of the present invention, a part of the transmission member may be provided with a biased portion that is offset in a predetermined direction from the axis center to suppress a decrease in the flow path area in the open valve state. This invention can achieve the same effects as those achieved by the biased portion described above.

[0041] The present invention provides a butterfly valve that can obtain a stable high compression surface pressure.

[0042] Explanatory diagram of a butterfly valve. Explanatory diagram of a butterfly valve. Explanatory diagram of a butterfly valve. Explanatory diagram of a butterfly valve. Explanatory diagram of an opening and closing mechanism. Explanatory diagram of a rotational movement conversion mechanism. Exploded perspective view of a main body mechanism. Exploded perspective view of a main body mechanism. Explanatory diagram of opening and closing operations. Explanatory diagram of an opening and closing mechanism of another form. Explanatory diagram of a rotational movement conversion mechanism of another form. Explanatory diagram of an opening and closing operation of another form. Explanatory diagram of a rotational movement conversion mechanism of yet another form. Explanatory diagram of an opening and closing operation of yet another form.

[0043] An embodiment of the present invention will be described below with reference to the drawings. Figures 1 to 5 are explanatory diagrams of a butterfly valve 1, Figure 6 is an explanatory diagram of an opening / closing mechanism Y, Figure 7 is an explanatory diagram of a rotation-to-movement conversion mechanism MD, Figures 8 and 9 are exploded perspective views of a main mechanism X, and Figure 10 is an explanatory diagram of the opening and closing operation of the butterfly valve 1.

[0044] 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.

[0045] Fig. 3(a) shows a view taken along arrows A-A in Fig. 1(a) in a state rotated 90 degrees, and Fig. 3(b) shows a view taken along arrows B-B in Fig. 3(a). Fig. 4(a) shows a schematic perspective view of the front, right side and top view seen through the main body mechanism X of the butterfly valve 1 in an open state, Fig. 4(b) shows a schematic perspective view of the front, right side and top view seen through the main body mechanism X of the butterfly valve 1 in a closed state, and Fig. 4(c) shows a schematic perspective view of the front, right side and top view seen through the opening and closing mechanism Y of the butterfly valve 1.

[0046] Figure 5(a) is a schematic perspective view showing the back, left side, and bottom of the butterfly valve 1 in an open state, with the main body mechanism X seen through; Figure 5(b) is a schematic perspective view showing the back, left side, and bottom of the butterfly valve 1 in a closed state, with the main body mechanism X seen through; and Figure 5(c) is a schematic perspective view showing the back, left side, and bottom of the butterfly valve 1 in a closed state, with the opening / closing mechanism Y seen through.

[0047] Fig. 6(a) is a schematic exploded perspective view showing the front, right side, and plan of the opening / closing mechanism Y, and Fig. 6(b) is a schematic exploded perspective view showing the back, left side, and bottom of the opening / closing mechanism Y. Note that the over-rotation prevention bolt 95 is not shown in Figs. 4 to 6. Fig. 7(a) is an enlarged plan view of the cam groove 54 provided in the horizontal portion 53 of the push-in base 51 that constitutes the rotational movement conversion mechanism MD, and Fig. 7(b) is an enlarged plan view of the cam 80 that constitutes the rotational movement conversion mechanism MD.

[0048] Figure 8 shows a schematic exploded perspective view illustrating the front, right side, and plan of the main mechanism X, and Figure 9 shows a schematic exploded perspective view illustrating the back, left side, and bottom of the main mechanism X. Figure 10 explains the opening and closing operation of the butterfly valve 1. Figure 10(a) shows a view taken along arrows CC in Figure 3(b) in the open state, Figure 10(b) shows a view taken along arrows DD in Figure 3(b) in the same state, and Figure 10(c) shows a view taken along arrows E-E in Figure 3(b) in the same state.

[0049] 10(d) shows a view as viewed from the arrows CC in FIG. 3(b) in a 45-degree rotated state in which the valve stem 40 has been rotated 45 degrees clockwise from the open valve state, FIG. 10(e) shows a view as viewed from the arrows DD in FIG. 3(b) in the same state, and FIG. 10(f) shows a view as viewed from the arrows EE in FIG. 3(b) in the same state.

[0050] Furthermore, Figure 10(g) shows a view as viewed from the arrows CC in Figure 3(b) in a state in which the valve stem 40 has been rotated 135 degrees clockwise from the open state, Figure 10(h) shows a view as viewed from the arrows DD in Figure 3(b) in the same state, and Figure 10(i) shows a view as viewed from the arrows EE in Figure 3(b) in the same state.

[0051] Furthermore, Figure 10(j) shows a view taken along the arrows CC in Figure 3(b) in a closed valve state in which the valve stem 40 has been rotated 180 degrees clockwise from the open valve state, Figure 10(k) shows a view taken along the arrows DD in Figure 3(b) in the same state, and Figure 10(l) shows a view taken along the arrows EE in Figure 3(b) in the same state.

[0052] In the above drawings, bolt holes for inserting or fastening bolts, the bolts themselves, etc. are partially omitted. In addition, in Fig. 1(a), the up-and-down 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.

[0053] 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, the width direction W, which is the direction connecting the upper left and lower right, refers to the left side WL, the lower right side refers to the right side WR, and the depth direction D, which is the direction connecting the upper right and lower left, refers to the back side DB, and the lower right side refers to 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.

[0054] 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 a fluid such as a liquid through the pipeline, and to adjust the flow rate, and is also known as a central butterfly valve.

[0055] 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.

[0056] 8 and 9, the main body mechanism X includes a valve box 10, a seat ring 20, a stop ring 31, and a fixing ring 32. The valve box 10 includes a tube main body 11 formed in an approximately cylindrical shape in an inverted position, which has a flow path F extending along the depth direction D and penetrating therethrough, 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.

[0057] As shown in Fig. 8, the front side of the cylindrical main body 11 is provided with an attachment portion 111 for attaching the seat ring 20. The attachment portion 111 protrudes radially inward from the inner surface of the main body 11 at a position extending from the end of the front side DF of the main body 11 to the rear side DB of the main body 11, and has a plurality of bolt holes (not shown) arranged at predetermined intervals in the circumferential direction for fastening bolts for fastening the fixing ring 32 (described later). The radially inner side of the attachment portion 111 protruding radially inward from the inner surface of the main body 11 forms a flow opening 112.

[0058] 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 at 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 tube main body portion 11 in the height direction H, and are constructed as a single unit. As described above, the valve box 10, in which the tube main body portion 11 and the base portions 12 are constructed as a single unit, is made of metal.

[0059] The seat ring 20 is a sealing member attached to the attachment portion 111 of the tube main body 11, and abuts against a 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 abutting against and sealing against the valve body 50, and is made of an elastic material with appropriate elasticity.

[0060] The retaining ring 31 is a flat ring plate formed in substantially the same ring shape as the seat ring 20 when viewed from the depth direction D, and is disposed between the seat ring 20 and a fixing ring 32 for fixing the seat ring 20 attached to the attachment portion 111 to the attachment portion 111. The retaining ring 31 is made of a plate material having higher rigidity than the seat ring 20, such as resin or metal.

[0061] 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 ring 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.

[0062] By using the seat ring 20, the presser ring 31, and the fixing ring 32 configured as described above, the seat ring 20 can be attached and fixed to the mounting portion 111 of the tube main body 11. Specifically, the seat ring 20 is attached to the mounting portion 111 of the tube main body 11, and the presser ring 31 is placed on the front side DF of the seat ring 20. The fixing ring 32 is then placed on the front side DF of the seat ring 20, and the bolts are fastened to the mounting portion 111 of the tube main body 11 at the bolt placement portions 321 of the fixing ring 32. This allows the seat ring 20, which is placed between the mounting portion 111 and the fixing ring 32, to be pressed and fixed by the presser ring 31, thereby forming a main body mechanism X in which the seat ring 20 is attached to the valve box 10.

[0063] The opening / closing mechanism Y, which is assembled to the main mechanism X and constitutes the butterfly valve 1, includes a valve stem 40 rotatably mounted on the valve box 10, a valve disc 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 guide 70, a cam 80, and a cam link 90. ​​There is one valve disc 50, one push-in base 51, and one cam link 90, and two valve stems 40, two fixed bases 60, two guides 70, and two cams 80, which are arranged symmetrically above and below.

[0064] The valve rod 40 is formed in a substantially cylindrical shape with a predetermined length in the height direction H, and is formed at an end in the height direction H with a predetermined height and a square shape in bottom view, and is provided with a square fitting portion 41 that fits into the fitting hole 81 of the cam 80 and the fitting hole 93 of the cam link 90. ​​Note that the square fitting portion 41 is formed slightly longer in the height direction H than the sum of the thickness of the cam 80 and the thickness of the horizontal arm 91 of the cam link 90, which will be described later.

[0065] 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 has an operating part 42 at its upper end to which a handle or a gripping part of an actuator can be attached.

[0066] In contrast, the valve stem 40B arranged on the lower side HD is upside down to the valve stem 40A as shown in Figure 3(b), has a rectangular fitting portion 41 on the upper side HU, and is formed shorter by the operating portion 42 of the valve stem 40A. In the butterfly valve 1 described in this embodiment, of the rotation directions of the valve stem 40 in a plan view, clockwise rotation in a plan view rotates in the valve closing direction, and counterclockwise rotation in a plan view rotates in the valve opening direction.

[0067] The valve element 50 is rotated by the valve rod 40 via a push-in base 51 (described later) to open and close the flow path F, and is formed in a generally disk-like shape centered on a horizontal axis perpendicular to the height direction H. More specifically, the valve element 50 is a metal disk-like element with a diameter slightly larger than the flow opening 112 of the cylindrical main body 11 of the valve box 10, and is erected so that its central axis is horizontal. Note that, in the orientation shown in FIG. 6( a), the diameter of the valve element 50 is slightly reduced toward the front side DF.

[0068] The push-in base 51 is a base for fixing the valve body 50 and rotating it by the rotation of the valve rod 40, and is formed into an inverted square U-shape when viewed horizontally, with a vertical portion 52 and horizontal portions 53 provided on both sides of the vertical portion 52 in the height direction H, which have cam grooves 54 and are provided with placement grooves 55 for placing the guide 70.

[0069] In detail, the vertical 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 has an attachment portion in the center for attaching the valve body 50.

[0070] In the state shown in FIG. 6( a), the horizontal portion 53 has a rectangular shape in plan view, with its length in the depth direction D being slightly longer than its width direction W, and is provided with a cam groove 54 and a positioning groove 55. The cam groove 54 and the positioning groove 55 are each formed to be approximately half the thickness of the horizontal portion 53, and the positioning groove 55 is provided on the outer side in the height direction H of the pushing base 51, which has an inverted square U shape when viewed horizontally, while the cam groove 54 is provided on the inner side in the height direction H. More specifically, the positioning groove 55 is provided on the upper surface side of the horizontal portion 53 of the upper side HU, and the cam groove 54 is provided on the lower surface side. Conversely, the cam groove 54 is provided on the upper surface side of the horizontal portion 53 of the lower side HD, and the positioning groove 55 is provided on the lower surface side.

[0071] The cam groove 54 is a groove in which a cam 80 (described later) is placed, and which is engaged or pushed in by the rotation of the cam 80 accompanying the rotation of the valve stem 40, and is formed with approximately the same height as the thickness of the cam 80. The shape of the cam groove 54 will be described in detail later, together with the shape of the cam 80.

[0072] The arrangement groove 55 is formed with a planar shape and depth that allows a base portion 72 of the guide 70, which will be described later, to fit into it. Therefore, when the base portion 72 is fitted into the arrangement groove 55, the push-in base 51 and the guide 70 are rotationally fixed.

[0073] The fixed base 60 is composed of a plate-shaped base main body 61 fixed to the pedestal 12 of the valve box 10, and a cylindrical protrusion 62 protruding in the height direction H from the base main body 61. The fixed base 60 arranged on the upper HU of the valve box 10 has the cylindrical protrusion 62 extending from the bottom surface of the base main body 61 toward the lower HD, while the fixed base 60 arranged on the lower HD of the valve box 10 has the cylindrical protrusion 62 extending from the top surface of the base main 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.

[0074] The base body 61 is formed in substantially the same shape as the pedestal 12 of the valve box 10 in a plan view, and is configured to be fastened to the pedestal 12 with bolts (not shown). The cylindrical protrusion 62 is cylindrical in shape with a diameter that can 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).

[0075] The tip of the cylindrical protrusion 62 forms a rotation restriction groove 63 into which a convex portion 71 of the guide 70 (described later) fits loosely. The rotation restriction groove 63 restricts rotation of the convex portion 71 and allows movement in a predetermined direction. As shown in FIGS. 10( a), (d), (g), and (j), the groove frame 631 constituting the rotation restriction groove 63 has a frame opening 632 on the front side DF that allows relative movement of the convex portion 71 toward the front side DF. It also has an arc-shaped frame 633 extending approximately halfway around the left side WL of the frame opening 632, and a circular side frame 634 on the right side WR, which has a surface along the depth direction D. The inner surface of the circular side frame 634 is provided with an arc-shaped recess 635 on the right side WR, along which the arc-shaped portion of the convex portion 71 can slide. The frame opening 632 is formed with an opening width slightly larger than the length in the minor axis direction of the convex portion 71, which is generally rounded and shaped like a bale, as described later.

[0076] The groove frame 631 is surrounded by the arc frame 633 and the circular side frame 634 configured as described above, and communicates with the frame opening 632, allowing the convex portion 71 of the guide 70, which will be described later, to fit loosely. The rotation restriction groove 63 is formed on the bottom surface of the cylindrical protrusion 62 of the fixed base 60 arranged on the upper side HU of the valve box 10, and is also formed on the top surface of the cylindrical protrusion 62 of the fixed base 60 arranged on the lower side HD of the valve box 10.

[0077] 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.

[0078] The fixed base 60 located on the lower side HD of the valve box 10 is provided with a support metal fitting 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 on the upper side HU is provided with a pull-out prevention ring 66 that prevents the inserted valve stem 40A from coming out.

[0079] The guide 70 comprises a convex portion 71 that fits loosely into the rotation restriction groove 63 of the fixed base 60 described above, and a base portion 72 that fits into the placement groove 55 of the push-in base 51, and is formed in an approximately convex shape when viewed horizontally, with a through hole 73 that penetrates in the height direction H provided near the center when viewed in a plane.

[0080] The convex portion 71 is formed in a generally bale shape in plan view that is longer in the depth direction D than in the width direction W, and the base portion 72 is formed in a generally rectangular shape in plan view that is longer in the depth direction D than in the width direction W. The convex portion 71 and the base portion 72 are made of metal and are integrally formed.

[0081] The through-hole 73, which is provided at the approximate center of the guide 70 in a plan view and penetrates in the height direction H, has a width that allows the valve stem 40 to be inserted therethrough and is formed in an approximate bale shape in a plan view that is long in the longitudinal direction. Therefore, the valve stem 40 inserted through the through-hole 73 and the guide 70 can move relative to each other in the longitudinal direction.

[0082] The cam 80 is a plate-like cam having a fitting hole 81 that fits with the rectangular fitting portion 41 of the valve stem 40, and is formed in a generally bell-like shape with an arc-shaped bottom in a plan view as shown in Figures 10(b), (e), (h), and (k). More specifically, the fitting hole 81 is a square through-hole that is slightly larger than the planar shape of the rectangular fitting portion 41, which is square in bottom view, so that the fitting hole 81 fits with the rectangular fitting portion 41.

[0083] 7(b), the cam 80 has a generally bell-shaped outer shape in a plan view, and is formed of a semicircular portion 82 formed in a semicircular shape centered on the center of the fitting hole 81, a straight portion 83 extending linearly from the semicircular portion 82, and an arc-shaped portion 84 that is continuous with the straight portion 83 and is provided on the opposite side of the center to the semicircular portion 82. The arc-shaped portion 84 has a larger radius than the semicircular portion 82.

[0084] Furthermore, the cam groove 54 into which the above-mentioned cam 80 fits loosely has a shape similar to that of a cam 80 in a push-in base 51 with the vertical portion 52 facing the front of the front side DF, with the arc-shaped portion 84 facing in the direction of the right side WR, as shown in Figure 7 (a).

[0085] More specifically, half of the cam groove 54 in the depth direction D has the same shape as half of the cam 80 in the depth direction D when the arc-shaped portion 84 is oriented to the right side WR, and has a small arc-shaped portion 541 corresponding to the semicircular portion 82, a straight portion 542 that corresponds to the straight portion 83 and extends in the width direction W, and a large arc-shaped portion 543 that corresponds to the arc-shaped portion 84. Furthermore, these are inverted near the center of the horizontal portion 53 in the depth direction D and are connected by a straight portion 544 along the depth direction D to form the cam groove 54.

[0086] In the cam groove 54 formed in this manner, the portion formed by the small arc-shaped portion 541, the straight portion 542, and the large arc-shaped portion 543 has the same shape as half of the cam 80, as described above, and is formed by connecting them with the straight portion 544 in the depth direction D, so the cam groove 54 and the cam 80 have similar shapes.

[0087] In the cam groove 54, the large arc-shaped portion 543 is a recess corresponding to the arc-shaped portion 84 of the cam 80, and the straight portion 542 continuing from the large arc-shaped portion 543 is closer to the center of the cam groove 54 than the other small arc-shaped portions 541, the large arc-shaped portion 543, and the straight portion 544, and serves as a pressing surface that is pressed by the arc-shaped portion 84 of the cam 80.

[0088] The cam link 90 is arranged at a predetermined interval in the height direction H, and is formed into an inverted angular U-shape when viewed horizontally, by a pair of horizontal arms 91 extending parallel to the horizontal direction and a vertical connecting portion 92 connecting one end of the horizontal arm 91 in the height direction H.

[0089] The horizontal arm 91 is formed to be longer than the length in the depth direction D of the horizontal portion 53 of the push-in base 51, and is provided with a square fitting hole 93 in plan view near the end opposite the side where the vertical connecting portion 92 is provided, into which the rectangular fitting portion 41 of the valve stem 40 fits. Also, a hook-shaped portion 94 that protrudes horizontally and perpendicularly to the horizontal arm 91 is provided near the end of the horizontal arm 91 opposite the side where the vertical connecting portion 92 is provided, forming the cam link 90 into a generally L-shaped shape in plan view.

[0090] Additionally, an over-rotation prevention bolt 95 that prevents over-rotation relative to the push-in base 51 is provided near the center of the length of the horizontal arm 91 of the cam link 90 and on the hook-shaped portion 94. Specifically, the over-rotation prevention bolt 95 is provided near the center of the length of the horizontal arm 91 so as to protrude toward the side opposite to the side from which the hook-shaped portion 94 protrudes. Additionally, the over-rotation prevention bolt 95 is provided on the hook-shaped portion 94 so as to protrude toward the side opposite to the direction in which the horizontal arm 91 extends.

[0091] In this way, when the cam link 90 provided with the over-rotation prevention bolt 95 rotates counterclockwise by a predetermined angle relative to the push-in base 51 as viewed from above, the over-rotation prevention bolt 95 provided on the hook-shaped portion 94 comes into contact with the vertical portion 52, preventing over-rotation in the counterclockwise direction. Conversely, when the cam link 90 provided with the over-rotation prevention bolt 95 rotates clockwise by a predetermined angle relative to the push-in base 51 as viewed from above, the over-rotation prevention bolt 95 provided on the horizontal arm 91 comes into contact with the vertical portion 52, preventing over-rotation in the clockwise direction.

[0092] The vertical connecting portions 92 that connect one ends of the horizontal arms 91 arranged at a predetermined interval in the height direction H to each other are formed to be lower in the height direction H than the vertical portions 52 of the pushing bases 51. Therefore, the cam links 90 formed in an inverted square U-shape when viewed horizontally can be placed between the horizontal portions 53 of the pushing bases 51 that are formed in an inverted square U-shape when viewed horizontally.

[0093] The valve rod 40 (40A, 40B), valve body 50, push-in base 51, fixed base 60, guide 70, cam 80, and cam link 90, each of which has been configured as described above, are assembled to form the opening / closing mechanism Y. Specifically, the valve body 50 is attached to the vertical portion 52 of the push-in base 51 to form an integrated structure.

[0094] The cam link 90 is positioned between the horizontal portions 53 of the pushing base 51 in the height direction H, the cam 80 is positioned in the cam groove 54, and the guide 70 is positioned in the placement groove 55. In other words, the cam link 90, the cam 80 positioned in the cam groove 54, and the guide 70 positioned in the placement groove 55 are positioned in this order in the height direction H between the horizontal portions 53 of the pushing base 51 in the height direction H. At this time, the fitting hole 93 of the horizontal arm 91 of the cam link 90 positioned between the horizontal portions 53 and the fitting hole 81 of the cam 80 positioned in the cam groove 54 are aligned in the height direction H to communicate with each other. Specifically, the pushing base 51 is positioned so that the vertical portion 52 faces the front side DF, and the cam link 90 is positioned so that the horizontal arm 91 faces the rear side DB, and the cam 80 is positioned so that the arc-shaped portion 84 faces the rear side DB and the right side WR. In this state, the cam link 90 is placed in the flow path F of the main body mechanism X.

[0095] Then, the fixed base 60 is attached to the pedestal 12 of the valve box 10 that constitutes the main mechanism X. Specifically, the fixed base 60 is placed on the pedestal 12 so that the cylindrical protrusion 62 of the fixed base 60 is inserted into the through-hole 121 of the pedestal 12 of the valve box 10, and is fixed with bolts (not shown). At this time, the convex portion 71 of the guide 70 that fits into the placement groove 55 of the opening / closing mechanism Y that has been placed in the flow path F in advance is inserted into the rotation restriction groove 63 provided at the end of the cylindrical protrusion 62 of the fixed base 60, as shown in Figure 3.

[0096] The valve stem 40 is then attached by inserting it through the insertion hole 64 of the fixed base 60. At this time, the valve stem 40 is inserted into the through-hole 73 of the guide 70 which fits into the placement groove 55 of the opening / closing mechanism Y arranged in the flow path F, and the square fitting portion 41 is inserted and fitted into the fitting hole 81 of the cam 80 which communicates in the height direction H and the fitting hole 93 of the cam link 90, thereby forming the opening / closing mechanism Y. The butterfly valve 1 is then formed by assembling the opening / closing mechanism Y to the main body mechanism X as described above. Note that, by attaching a removal prevention ring 66 to the fixed base 60 of the upper HU and a support metal fitting 65 to the fixed base 60 of the lower HD for the valve stem 40 inserted into the insertion hole 64 of the fixed base 60, it is possible to prevent the valve stem 40 from being accidentally removed.

[0097] The cam 80, whose square fitting portion 41 of the valve stem 40 is fitted into the fitting hole 81, and the cam link 90, whose fitting hole 93 is fitted into the fitting hole 81, are integrated together. Therefore, the cam 80 and the cam link 90 are also integrated together via the square fitting portion 41 of the valve stem 40.

[0098] In contrast, the valve rod 40 inserted into the through hole 73 can rotate freely relative to the guide 70, and the through hole 73 is formed in a roughly bale-like shape in a plan view that is long in the longitudinal direction.Therefore, the valve rod 40 and the guide 70 can move relative to each other within a predetermined range in the long axis direction, but relative movement in the short axis direction is restricted.

[0099] Furthermore, since the guide 70 is fitted into the placement groove 55 of the push-in base 51, the valve rod 40 is freely rotatable with respect to the push-in base 51 to which the valve body 50 is attached, and can move relative to it within a predetermined range in the long axis direction, but relative movement in the short axis direction is restricted.

[0100] Furthermore, the cam 80 and cam link 90, whose square fitting portion 41 of the valve stem 40 is rotatably assembled to the push-in base 51 and fitted into the fitting holes 81 and 93, also rotate together with the push-in base 51 as the valve stem 40 rotates, and also rotate relative to the push-in base 51. Specifically, when the valve stem 40 rotates up to a predetermined angle, the cam 80 and cam link 90 also rotate together with the push-in base 51, and when the valve stem 40 rotates beyond the predetermined angle, the cam 80 and cam link 90 rotate relative to the push-in base 51. Therefore, when the valve stem 40 rotates beyond the predetermined angle, the cam 80 rotates relatively within the cam groove 54 of the push-in base 51.

[0101] As the cam 80 rotates relative to the cam groove 54 of the push-in base 51, the arc-shaped portion 84 of the cam 80, which is longer from the center of the fitting hole 81 than the semicircular portion 82, functions as a rotational movement conversion mechanism MD that presses and moves the straight portion 542 of the inner circumferential surface of the cam groove 54. In other words, the cam groove 54 of the push-in base 51 and the cam 80, which rotates together with the valve stem 40 when the valve stem 40 rotates up to a predetermined angle, and acts in the direction in which the push-in base 51 moves when the valve stem 40 rotates beyond the predetermined angle, can function as a rotational movement conversion mechanism MD in the butterfly valve 1.

[0102] Furthermore, in the opening / closing mechanism Y, as described above, the convex portion 71 of the guide 70, whose base portion 72 is fitted into the arrangement groove 55 of the push-in base 51, fits into the rotation restriction groove 63 at the tip of the cylindrical protrusion 62 of the fixed base 60. Specifically, the convex portion 71, which is roughly bale-shaped in plan view, fits between the arc frame 633 and the circular side frame 634 of the groove frame 631.

[0103] When the valve stem 40 rotates, as described above, the push-in base 51 rotates up to a predetermined angle in conjunction with the rotation of the valve stem 40. At this time, the guide 70, whose base portion 72 is fitted into the arrangement groove 55 of the push-in base 51, also rotates in conjunction with the rotation of the valve stem 40, and the convex portion 71, which is generally bale-shaped in plan view, also rotates between the arc frame 633 and the circular side frame 634.

[0104] When the valve stem 40 attempts to rotate beyond a predetermined angle, the side of the convex portion 71, which had been rotating with the valve stem 40 until then, abuts against the side surface of the circular side frame 634, restricting further rotation. However, since the rotation restricting groove 63 has a frame opening 632 formed on the front side DF with an opening width slightly larger than the length in the minor axis direction of the approximately bale-shaped convex portion 71, the convex portion 71 functions as a rotation restricting mechanism MR in the rotation restricting groove 63 by the frame opening 632, which allows it to move to the front side DF.

[0105] In this way, the convex portion 71 and the rotation restriction groove 63 into which the convex portion 71 fits function as a rotation restriction mechanism MR that allows rotation with the rotation of the valve stem 40 up to a predetermined angle, restricts rotation when the valve stem 40 rotates beyond the predetermined angle, but allows movement toward the front side DF. The rotation restriction mechanism MR also functions as a movement direction restriction means that restricts the movement direction of the convex portion 71, i.e., the movement direction of the valve disc 50. The rotation movement conversion mechanism MD and rotation restriction mechanism MR configured in this way are arranged on both sides of the valve disc 50 in the height direction H.

[0106] Next, the operation of a butterfly valve 1 in which the main body mechanism X and opening / closing mechanism Y are assembled and which has the rotational movement conversion mechanism MD and rotation restriction mechanism MR will be described with reference to Figure 10. Figures 10(a) to (c) show the open state in which the valve stem 40 is rotated fully counterclockwise, Figures 10(d) to (f) show the state in which the valve stem 40 is rotated 45 degrees clockwise from the open state, Figures 10(g) to (i) show the state in which the valve stem 40 is rotated 135 degrees clockwise from the open state, and Figures 10(j) to (l) show the state in which the valve stem 40 is rotated 180 degrees clockwise from the open state, i.e., the closed state in which the valve stem 40 is rotated fully clockwise.

[0107] In other words, the butterfly valve 1 can be switched from an open state in which the valve stem 40 is rotated fully counterclockwise to a closed state in which the valve stem 40 is rotated fully clockwise by rotating it 180 degrees.

[0108] Note that the CC arrow views of Figure 3(b) shown in Figures 10(a), (d), (g), and (j) illustrate the state in which the convex portion 71 of the guide 70 is fitted into the rotation restriction groove 63 at the tip of the cylindrical protrusion 62 of the fixed base 60, i.e., the state of the rotation restriction mechanism MR.

[0109] 10(b), (e), (h), and (k) show views taken along the arrows D-D in Fig. 3(b) in which the cam 80 is fitted into the cam groove 54 in the horizontal portion 53 of the push-in base 51, i.e., the state of the rotational movement conversion mechanism MD. Furthermore, Figs. 10(c), (f), (i), and (l) show views taken along the arrows E-E in Fig. 3(b) in which the valve element 50 is in the flow path F.

[0110] 10, the left-right direction indicates the width direction W, the left side indicates the left side WL, and the right side indicates the right side WR. Also, in FIG. 10, the up-down direction indicates the depth direction D, and further, the down direction indicates the front side DF and the up direction indicates the back side DB.

[0111] The operation of the butterfly valve 1 from the open state shown in Figures 10(a) to 10(c) to the closed state shown in Figures 10(j) to 10(l), more specifically, the operation of the rotational movement conversion mechanism MD, the rotation restriction mechanism MR, and the valve body 50 from the open state to the closed state, will be described below.

[0112] In the open state, which is referred to herein as the initial state, as shown in Figures 2(a), 2(b), 4(a), 5(a), and 10(c), the valve element 50 attached to the vertical portion 52 of the push-in base 51 is positioned so that it faces the right side WR in the flow path F of the valve box 10. The push-in base 51 and the cam link 90 are positioned so that the vertical portion 52 of the push-in base 51 and the vertical connecting portion 92 of the cam link 90 face each other in the width direction W. Therefore, the vertical portion 52 and upper and lower horizontal portions 53 of the push-in base 51, the vertical connecting portion 92 of the cam link 90, and the upper and lower horizontal arms 91 form a substantially rectangular frame with an opening in the depth direction D. Therefore, in the butterfly valve 1, fluid passing through the flow path F can flow through the communication opening 112.

[0113] At this time, in the rotation restriction mechanism MR, the approximately bale-shaped convex portion 71 is arranged in the rotation restriction groove 63 with its major axis oriented along the width direction W. In the rotation movement conversion mechanism MD, the vertical portion 52 of the pushing base 51 is on the right side WR. In other words, the horizontal portion 53 having the cam groove 54 is oriented along the width direction W, and the cam 80 is arranged inside the cam groove 54 with the arc-shaped portion 84 oriented on the left side WL and the rear side DB.

[0114] In this state, rotation is not restricted by the rotation restriction mechanism MR, so when the valve stem 40 is rotated clockwise by a predetermined angle of 45 degrees from the open state, the cam 80 and cam link 90 rotate 45 degrees clockwise in conjunction with the clockwise rotation of the valve stem 40 (see FIG. 10( e)). However, even when the valve stem 40 rotates, the push-in base 51, whose base portion 72 fits into the arrangement groove 55, does not rotate (see FIG. 10( d)).

[0115] As described above, when the valve stem 40 is further rotated to the 135-degree position while the rotation restriction mechanism MR restricts further clockwise rotation of the convex portion 71, the cam 80 and cam link 90 rotate to the 135-degree position (see FIG. 10(i)). Then, as the cam 80 and cam link 90 rotate, the push-in base 51 and guide 70 to which the valve disc 50 is attached also rotate clockwise to the 135-degree position (see FIG. 10(d)). Therefore, the valve disc 50 attached to the vertical portion 52 of the push-in base 51 faces the front side DF, but there is a gap between the valve disc 50 and the seat ring 20 attached to the attachment portion 111, and the valve disc 50 is not sealed (see FIG. 10(f)).

[0116] 10(d), in this state, the convex portion 71, which is formed in a generally bale shape in plan view, is oriented in the rotation restricting groove 63 with its major axis facing the depth direction D, and its side portion abuts against the side surface of the circular side frame 634. Therefore, the convex portion 71, whose side portion abuts against the side surface of the circular side frame 634, is restricted from further rotation in the rotation restricting groove 63, but the frame opening 632 is located on the front side DF of the convex portion 71, whose major axis is oriented along the depth direction D, allowing movement of the convex portion 71 on the front side DF. In other words, when the valve stem 40 is rotated clockwise to a position of 135 degrees from the initial state, the rotation restricting mechanism MR restricts further rotation of the convex portion 71 but allows movement of the convex portion 71 to the front side DF. Therefore, the cam 80 rotates by 90 degrees relative to the cam groove 54 until the tip end of the arcuate portion 84 in the rotation direction abuts against the inner surface of the cam groove 54 (see FIG. 10(h)).

[0117] In this state, if the valve stem 40 is further rotated to the 180-degree position, the cam 80 and cam link 90 will also rotate to the 180-degree position (see FIG. 10(l)). However, because the rotation restriction groove 63 constituting the rotation restriction mechanism MR restricts further clockwise rotation of the convex portion 71, the base portion 72 does not rotate relative to the placement groove 55 even when the valve stem 40 rotates (see FIG. 10(j)). Therefore, in the cam groove 54, the cam 80 rotates 45 degrees relative to the cam groove 54 so that the arc-shaped portion 84 presses the linear portion 542, which is the inner surface of the cam groove 54, toward the near side DF (see FIG. 10(h)). Therefore, the linear portion 542 of the cam groove 54 is pressed toward the near side DF by the arc-shaped portion 84, and the pushing base 51 moves toward the near side DF. At this time, the long axis direction of the through hole 73 of the guide 70 is oriented along the depth direction D, and the convex portion 71 moves relative to the valve rod 40 toward the front side DF through the frame opening 632 of the rotation restriction groove 63 (see Figure 10 (j)).

[0118] In this way, further rotation of the valve rod 40 causes the arc-shaped portion 84 of the cam 80, which functions as the rotational movement conversion mechanism MD, to push the straight portion 542 of the cam groove 54 toward the front side DF, causing the push-in base 51 to which the valve body 50 is attached to move toward the front side DF, and the valve body 50 comes into close contact with the seat ring 20 attached to the mounting portion 111, thereby sealing the flow opening 112.

[0119] At this time, the over-rotation prevention bolt 95 attached to the horizontal arm 91 of the cam link 90 abuts against the vertical portion 52, restricting further clockwise relative rotation of the cam link 90 with respect to the push-in base 51.

[0120] In this way, the valve stem 40 is rotated clockwise from the initial open state to a position of 180 degrees to enter the closed state, but the valve can be opened by rotating the valve stem 40 counterclockwise from this closed state to a position of 180 degrees.

[0121] Specifically, when the valve stem 40 is rotated counterclockwise to a 45-degree position, the cam 80 and the cam link 90 rotate 45 degrees counterclockwise in conjunction with the rotation of the valve stem 40. However, even when the valve stem 40 rotates, the push-in base 51, whose base portion 72 fits into the arrangement groove 55, does not rotate.

[0122] In this state, when the valve stem 40 is further rotated counterclockwise to the 90-degree position, the cam 80 and the cam link 90 rotate counterclockwise to the 90-degree position. As a result, the cam groove 54 rotates counterclockwise by 45 degrees relative to the cam link 90, and the push-in base 51 moves to the rear DB. In other words, the valve disc 50 is pulled into the rear DB, and the intimate contact between the valve disc 50 and the seat ring 20 is released.

[0123] When the valve stem 40 is further rotated counterclockwise to the 180-degree position, i.e., to the valve open position, the cam 80 and cam link 90 also rotate counterclockwise to the 180-degree position, i.e., to the valve open position, in conjunction with the rotation of the valve stem 40. Then, in conjunction with the rotation of the cam 80 and cam link 90, the push-in base 51 and guide 70 to which the valve disc 50 is attached also rotate counterclockwise to the 180-degree position, i.e., to the valve open position, and the valve is opened.

[0124] 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. A rotation-movement conversion mechanism MD is provided between the valve stem 40 and the valve disc 50. The rotation-movement conversion mechanism MD rotates the valve disc 50 as the valve stem 40 rotates from the valve open position to a 90-degree position, and moves the valve disc 50 so that it comes into close contact with the seat ring 20 when the valve stem 40 rotates clockwise beyond 135 degrees.

[0125] The rotational movement conversion mechanism MD has an arc-shaped portion 84, some of which have a longer diameter in the circumferential direction than other portions, and is equipped with a cam 80 provided on the valve stem 40 and a cam groove 54 provided on the valve body 50, into which the cam 80 fits.

[0126] The cam groove 54 is provided with a large arc-shaped portion 543 corresponding to the arc-shaped portion 84, and a straight portion 542 that is continuous with the large arc-shaped portion 543 and is pressed in by the arc-shaped portion 84. When the valve stem 40 rotates more than 135 degrees, the rotation-to-movement converting mechanism MD causes the arc-shaped portion 84 to escape from the large arc-shaped portion 543 and press in on the straight portion 542, moving the valve disc 50 from the axis along the flow path F so as to be in close contact with the seat ring 20. Therefore, even with a high-pressure fluid, a stable high compression surface pressure can be obtained in the closed valve state, and the flow path F can be reliably shut off.

[0127] In more detail, the rotational movement conversion mechanism MD in the butterfly valve 1, which rotates the valve element 50 using the valve stem 40 and abuts the valve element 50 against the seat ring 20 to open and close the flow path F of the valve box 10, rotates the valve element 50 as the valve stem 40 rotates from the open position to a position of 135 degrees, and can move the valve element 50 from the axis along the flow path F so that it is in close contact with the seat ring 20 as the valve stem 40 rotates clockwise beyond 135 degrees.

[0128] The rotation-to-movement conversion mechanism MD has an arc-shaped portion 84, some of which have a longer diameter in the circumferential direction than other portions, and is equipped with a cam 80 provided on the valve stem 40 and a cam groove 54 provided on the valve disc 50, into which the cam 80 fits, and the cam groove 54 is provided with a large arc-shaped portion 543 corresponding to the arc-shaped portion 84, and a straight portion 542 that is continuous with the large arc-shaped portion 543 and is pushed in by the arc-shaped portion 84. Therefore, when the valve stem 40 rotates beyond 135 degrees, the arc-shaped portion 84 escapes from the large arc-shaped portion 543 and pushes in the straight portion 542, moving the valve disc 50 from the axis along the flow path F so as to be in close contact with the seat ring 20.

[0129] 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. Because the valve disc 50 and the seat ring 20 transition to the closed state in which they are in close contact with each other under high compressive surface pressure, the operating torque of the valve stem 40 can be reduced, improving operability. Because the valve disc 50 and the seat ring 20 are in close contact with each other under high compressive surface pressure with a small operating torque, even when blocking the flow of fluids with small molecular sizes or extremely low temperatures (such as cryogenic fluids) toward the front side DF, as well as the flow of fluids toward the rear side DB (where pressure acts on the valve disc 50 in a valve-opening direction), the flow path F can be reliably blocked without fluid leaking out from between the seat ring 20 and the valve disc 50.

[0130] Furthermore, the rotation of the valve disc 50 is permitted from the valve open position of the valve stem 40 to a 90-degree position, and the rotation of the valve disc 50 accompanying clockwise rotation of the valve stem 40 exceeding 90 degrees is restricted, while the movement of the front side DF of the valve disc 50 is permitted. In other words, a rotation restriction mechanism MR is provided that also functions as a movement direction restriction mechanism.

[0131] Therefore, the rotation restriction mechanism MR restricts the rotation of the valve body 50 that accompanies clockwise rotation of the valve stem 40 exceeding 135 degrees, while in the closed valve state, the rotation movement conversion mechanism MD moves the valve body 50 toward the front side DF, thereby reliably blocking the flow path F.

[0132] In addition, the rotational movement conversion mechanism MD and the rotational restriction mechanism MR are provided on both sides of the valve body 50 in the height direction H, and a cam link 90 is provided to the rotational movement conversion mechanism MD and the rotational restriction mechanism MR on the lower HD of the rotational movement conversion mechanism MD and the rotational restriction mechanism MR provided on both sides of the valve body 50 in the height direction H, to transmit the rotational force of the valve rod 40.

[0133] Therefore, the cam link 90 can transmit the rotational force of the valve stem 40 to the rotational movement conversion mechanism MD and rotation restriction mechanism MR on the lower side HD of the rotational movement conversion mechanism MD and rotation restriction mechanism MR provided on both sides in the height direction H of the valve disc 50. Therefore, while the rotational movement conversion mechanism MD and rotation restriction mechanism MR provided on both sides in the height direction H restrict rotation of the valve disc 50 associated with clockwise rotation of the valve stem 40 exceeding 90 degrees, in the closed valve state, the rotational movement conversion mechanism MD can move the valve disc 50 to the near side DF, more reliably blocking the flow path F.

[0134] In addition, the cam link 90 is provided with a horizontal arm 91 and a vertical connecting portion 92 that are positioned in a predetermined direction from the axis to suppress a reduction in the area of ​​the flow path F in the open valve state.Therefore, in the closed valve state, the valve body 50 can be moved to the front side DF by the rotational movement conversion mechanism MD without reducing the flowability in the open valve state, thereby more reliably blocking the flow path F.

[0135] More specifically, the axis that is the center of rotation of the rotating valve stem 40 and valve element 50 is positioned so as to cross the tubular flow path F that is blocked by the valve element 50 in the closed position. Therefore, if a rotation transmission member that transmits the rotational force of the valve stem 40 is positioned at the axis of the rotational movement conversion mechanism MD and rotation restriction mechanism MR on the lower HD of the rotational movement conversion mechanism MD and rotation restriction mechanism MR provided on both sides of the valve element 50 in the height direction H, the flow path F will be crossed and the area of ​​the flow path F will be reduced in the open valve state, reducing the flowability in the open valve state.

[0136] In contrast, the cam link 90 is provided with a horizontal arm 91 and a vertical connecting portion 92 that are shifted in a predetermined direction from the axis, thereby suppressing a decrease in the area of ​​the flow path F in the open valve state. Therefore, while suppressing a decrease in flowability due to the cam link 90 in the open valve state, the valve element 50 can be moved to the front side DF by the rotational movement conversion mechanism MD in the closed valve state, thereby more reliably blocking the flow path F.

[0137] In addition, an over-rotation prevention bolt 95 is provided to prevent the valve stem 40 from rotating excessively, thereby preventing the valve stem 40 from rotating further from the valve closed position or the valve open position. This prevents loads from being applied to the valve stem 40, the valve disc 50, or the seat ring 20 due to excessive rotation of the valve stem 40.

[0138] Furthermore, when the butterfly valve 1 is in the closed state, rotating the valve stem 40 counterclockwise to a position of 90 degrees causes the push-in base 51 to move to the rear DB, and the valve body 50 is no longer in close contact with the seat ring 20. This reduces the torque required to operate the valve stem 40 when transitioning from the closed state to the open state, thereby improving operability.

[0139] Next, another embodiment of the present invention will be described with reference to the drawings. Figure 11 shows an explanatory diagram of an opening / closing mechanism Ys of another embodiment, Figure 12 shows an explanatory diagram of a rotational movement conversion mechanism MDs of another embodiment, and Figure 13 shows an explanatory diagram of the opening and closing operation of a butterfly valve 1 of another embodiment.

[0140] 11(a) and 11(b) are views corresponding to FIGS. 6(a) and 6(b). FIG. 12(a) is an enlarged plan view of a cam groove 54s provided on a horizontal portion 53s of a push-in base 51s constituting a rotational movement conversion mechanism MDs of another embodiment. FIG. 12(b) is an enlarged plan view of a cam 80s constituting the rotational movement conversion mechanism MDs. FIG. 12(c) is an enlarged plan view of the cam 80s fitted into the cam groove 54s in the valve open state. Note that in FIG. 12, the cam groove 54s, the cam 80s, and the rotational movement conversion mechanism MDs are illustrated in a direction in which the valve stem 40 has been rotated a predetermined amount (90 degrees) from the valve open state.

[0141] Figures 13(a) to 13(c) show views corresponding to Figures 10(a) to 10(c) of a butterfly valve 1 having an opening / closing mechanism Ys in an open state, and Figures 13(d) to 13(f) show views corresponding to Figures 10(d) to 10(f) of a state in which the valve stem 40 has been rotated 90 degrees clockwise from the open state.

[0142] 13(g) to 13(i) show views corresponding to FIGS. 10(g) to 10(i) in a state where the valve stem 40 has been rotated 135 degrees clockwise from the open state, and FIGS. 13(j) to 13(l) show views corresponding to FIGS. 10(j) to 10(l) in a state where the valve stem 40 has been rotated 180 degrees clockwise from the open state. In the above-mentioned drawings, the same components of the butterfly valve 1 equipped with the opening / closing mechanism Ys as those of the butterfly valve 1 equipped with the opening / closing mechanism Y are designated by the same reference numerals, and their description will be omitted.

[0143] Like the butterfly valve 1 equipped with the opening / closing mechanism Y, the butterfly valve 1 equipped with the opening / closing mechanism Ys is connected to a pipeline (not shown) such as a pipe arranged along the depth direction D, and is a valve device for allowing or blocking the flow of a fluid such as a liquid flowing through the pipeline, and for adjusting the flow rate, and is also called a central butterfly valve.

[0144] In the butterfly valve 1 equipped with the opening / closing mechanism Ys, the cam 80s in the opening / closing mechanism Ys and the cam groove 54s provided in the horizontal portion 53s of the pushing base 51s are different from the cam 80 and cam groove 54 in the opening / closing mechanism Y of the butterfly valve 1, but the other configurations of the main body mechanism X and the opening / closing mechanism Ys are the same as the other configurations of the main body mechanism X and the opening / closing mechanism Y of the butterfly valve 1. Therefore, the configuration of the cam 80s and cam groove 54s, and the operation of the opening / closing mechanism Ys equipped with the cam 80s and cam groove 54s will be described below.

[0145] The push-in base 51s, like the push-in base 51 of the opening / closing mechanism Y, is a base for fixing the valve body 50 and rotating it by the rotation of the valve rod 40, and is formed into an inverted angular U-shape when viewed horizontally, with a vertical portion 52 and horizontal portions 53s provided on both sides of the vertical portion 52 in the height direction H, having cam grooves 54s and having an arrangement groove 55 for arranging the guide 70.

[0146] 11(a), horizontal portion 53s has a rectangular shape in plan view that is slightly longer in depth direction D than in width direction W, and is provided with cam groove 54s and arrangement groove 55. Cam groove 54s and arrangement groove 55 are each formed to be approximately half the thickness of horizontal portion 53s, and arrangement groove 55 is provided on the outer side in height direction H of push-in base 51s, which is formed in an inverted square U-shape when viewed horizontally, and cam groove 54s is provided on the inner side in height direction H.

[0147] Like the cam groove 54, the cam groove 54s has the cam 80s (described later) placed inside, and is engaged or pushed in by the rotation of the cam 80s accompanying the rotation of the valve stem 40, and is formed at approximately the same height as the thickness of the cam 80s.

[0148] The cam groove 54s is a wide, approximately rectangular space in plan view, with its length in the width direction W being slightly longer than its depth length DL, which is its length in the depth direction D. In this embodiment, the cam groove 54s is formed to a length that is approximately half the length of the horizontal portion 53s in the depth direction D, and is formed to a length that is approximately two-thirds the length of the horizontal portion 53s in the width direction W.

[0149] The cam groove 54s formed in this manner is disposed so as to be shifted to the right side WR with respect to the center in the width direction W of the horizontal portion 53s, and is disposed so as to be shifted to the rear side DB with respect to the center in the depth direction D of the horizontal portion 53s. Note that the amount of shift in the depth direction D of the cam groove 54s disposed so as to be shifted to the right side WR with respect to the center in the width direction W of the horizontal portion 53s is set to be larger than the amount of shift in the depth direction D of the cam groove 54s disposed so as to be shifted to the rear side DB with respect to the center in the depth direction D of the horizontal portion 53s.

[0150] In addition, the inner surfaces on both sides of the cam groove 54s formed in this manner in the depth direction D are abutted surfaces 541s, the inner surface of the front side DF of the abutted surfaces 541s is a front inner surface 542s, and the inner surface of the rear side DB is a rear inner surface 543s.

[0151] The cam 80s is a plate-shaped cam having a fitting hole 81 that fits into the rectangular fitting portion 41 of the valve stem 40, and as shown in Figure 12(b), it has a shape in plan view that is different from the cam 80, which is formed in a generally bell shape with an arc-shaped bottom in plan view. The center of the fitting hole 81 is a first center Fc that coincides with the axis that is the center of the rectangular fitting portion 41 with which it fits.

[0152] More specifically, in the open valve state shown in Figure 12 (b), the planar shape of the cam 80s is such that a first straight portion 82s, a first arc-shaped portion 83s, a second straight portion 84s, a second arc-shaped portion 85s, a third arc-shaped portion 86s, a third straight portion 87s, and a fourth arc-shaped portion 88s are arranged in this order clockwise from the rear side DB in planar view.

[0153] In the open state shown in FIG. 12( b), the first straight portion 82s is linear from a first center Fc, which is the center of the fitting hole 81, at the farthest DB toward the right side WR. The first arc-shaped portion 83s continues from the end of the first straight portion 82s on the right side WR, extending in the width direction W, and is formed in an arc shape centered on the first center Fc and convex toward the right side WR and the far side DB. The radius of the first arc-shaped portion 83s is defined as a first radius R1. In this embodiment, the first arc-shaped portion 83s is formed in an approximately 45-degree arc shape centered on the first center Fc.

[0154] The second straight portion 84s continues from the end of the first arc-shaped portion 83s on the right side WR and the near side DF, and is formed in a straight line along the near side DF. The second arc-shaped portion 85s continues from the end of the second straight portion 84s on the near side DF, extending in the depth direction D, and is formed in a semicircular shape that is convex toward the right side WR and the near side DF, with its center at a second center Sc eccentric from the first center Fc. The radius of the second arc-shaped portion 85s is defined as a second radius R2.

[0155] Furthermore, the second center Sc, which is the center of the second arc-shaped portion 85s, is disposed at a position eccentric to the first center Fc, which is the center of the fitting hole 81, at a predetermined distance Z toward the rear side DB. Note that the predetermined distance Z at which the second center Sc is eccentric to the first center Fc toward the rear side DB is a distance that corresponds to the amount of movement of the valve body 50 toward the front side DF by the opening / closing mechanism Ys, which will be described later.

[0156] The third arc-shaped portion 86s is continuous with an end of the second arc-shaped portion 85s on the left side WL and the front side DF, is located on the opposite side of the first arc-shaped portion 83s with respect to the first center Fc, and is formed in a semicircular shape that is convex toward the left side WL and the front side DF. The third arc-shaped portion 86s is centered on the first center Fc, and its radius is defined as a third radius R3.

[0157] The third straight portion 87s continues from the end of the third arc-shaped portion 86s on the left side WL and the rear side DB, and forms a straight line along the rear side DB. The fourth arc-shaped portion 88s connects the end of the rear side DB of the third straight portion 87s extending in the depth direction D and the end of the left side WL of the first straight portion 82s extending in the width direction W, and is located on the opposite side of the second arc-shaped portion 85s with respect to the second center Sc, and forms a semicircle that is convex toward the left side WL and the rear side DB. The fourth arc-shaped portion 88s is centered at the second center Sc, and its radius is defined as a fourth radius R4.

[0158] That is, the first arc-shaped portion 83s formed with the first radius R1 and the third arc-shaped portion 86s formed with the third radius R3 are arc-shaped about the first center Fc and are arranged so that the convex directions on the opposite side from the first center Fc are opposite to each other. Note that the first radius R1 of the first arc-shaped portion 83s arranged on the far side DB where the second center Sc is arranged with respect to the first center Fc is set to be larger than the third radius R3 of the third arc-shaped portion 86s arranged on the near side DF with respect to the first center Fc.

[0159] The second arc-shaped portion 85s having the second radius R2 and the fourth arc-shaped portion 88s having the fourth radius R4 are arc-shaped about the second center Sc and are arranged such that the convex directions on the opposite side of the second center Sc are opposite to each other. The second radius R2 of the second arc-shaped portion 85s located on the front side DF relative to the second center Sc is set to be larger than the fourth radius R4 of the fourth arc-shaped portion 88s located on the back side DB where the second center Sc is located relative to the first center Fc.

[0160] The radii (R3, R4) of a third arc-shaped portion 86s centered on the first center Fc and a fourth arc-shaped portion 88s centered on the second center Sc, which are disposed on the left side WL of the first center Fc, are set to be the same. Furthermore, the first radius R1 of the first arc-shaped portion 83s centered on the first center Fc is set longer than the second radius R2 of the second arc-shaped portion 85s centered on the second center Sc, and the second radius R2 of the second arc-shaped portion 85s is set longer than the radii (R3, R4) of the third arc-shaped portion 86s and the fourth arc-shaped portion 88s.

[0161] Therefore, the distance between the first center Fc and the boundary between the second arc-shaped portion 85s and the third arc-shaped portion 86s, which is centered on the second center Sc, is a third radius R3 of the third arc-shaped portion 86s, and the distance between the second center Sc and the boundary between the second arc-shaped portion 85s and the third arc-shaped portion 86s is a second radius R2 of the second arc-shaped portion 85s, which is shorter than the first radius R1 of the first arc-shaped portion 83s. Therefore, in the second arc-shaped portion 85s, the distance from the first center Fc gradually increases from the boundary with the third arc-shaped portion 86s toward the boundary with the second arc-shaped portion 85s.

[0162] The distance between the first center Fc and the boundary between the fourth arc-shaped portion 88s and the first straight line portion 82s, which is centered on the second center Sc, is longer than the fourth radius R4. Specifically, the distance is set to the sum of the fourth radius R4 and the eccentricity of the second center Sc relative to the first center Fc. The distance between the first center Fc and the boundary between the fourth arc-shaped portion 88s and the third straight line portion 87s is longer than the fourth radius R4 but shorter than the sum of the fourth radius R4 and the eccentricity of the second center Sc. Therefore, the distance from the first center Fc of the fourth arc-shaped portion 88s gradually decreases from the boundary with the first straight line portion 82s toward the boundary with the third straight line portion 87s.

[0163] The length of the imaginary line VL that passes through the second center Sc and connects any point on the second arc-shaped portion 85s to any point on the fourth arc-shaped portion 88s is set to be constant at all times. Note that the length of the imaginary line VL that passes through the second center Sc and connects any point on the second arc-shaped portion 85s to any point on the fourth arc-shaped portion 88s is set to be equal to the depth length DL of the cam groove 54s.

[0164] Furthermore, the length of the first straight portion 82s along the width direction W, the length of the third straight portion 87s along the depth direction D, and the length of the second straight portion 84s along the depth direction D are set to decrease in this order. The length of the third straight portion 87s along the depth direction D is formed to a length corresponding to the predetermined distance Z of the second center Sc that is eccentric with respect to the first center Fc, that is, the amount of movement of the valve body 50 toward the front side DF by the opening / closing mechanism Ys.

[0165] The opening / closing mechanism Ys having the pushing base 51s with the cam groove 54s and the cam 80s configured as described above can be assembled and configured in the same manner as the above-described method of assembling the opening / closing mechanism Y. Note that in the opening / closing mechanism Ys having the pushing base 51s with the cam groove 54s and the cam 80s, the cam 80s is arranged in the cam groove 54s formed in a generally rectangular shape in plan view, with the width direction W being wider than the depth direction D, so that the first straight line portion 82s is on the far side DB, the second straight line portion 84s is on the right side WR, and the third straight line portion 87s is on the left side WL.

[0166] At this time, the boundary between the second arc-shaped portion 85s and the third arc-shaped portion 86s of the cam 80s abuts against a front inner surface 542s of the cam groove 54s, which is formed in a generally rectangular shape in plan view with a width direction W wider than a depth direction D, and the first straight portion 82s abuts against a rear inner surface 543s, which is the inner surface of the rear side DB of the cam groove 54s. In addition, the third straight portion 87s abuts against the inner surface of the left side WL of the cam groove 54s.

[0167] The first straight line portion 82s and the third straight line portion 87s, which are formed linearly in a plan view, are in face-to-face contact with the contacted surface 541s (542s, 543s) of the cam groove 54s in the depth direction D. In addition, when a portion of the cam 80s is in contact with the contacted surface 541s of the cam groove 54s, this may mean that the portion is actually in contact with the contacted surface 541s, or that a gap equivalent to a tolerance exists.

[0168] The butterfly valve 1 equipped with the opening / closing mechanism Ys configured by assembling the opening / closing mechanism Ys to the main mechanism X achieves the same effects as the butterfly valve 1 equipped with the above-described opening / closing mechanism Y. Next, the operation of the butterfly valve 1 equipped with the opening / closing mechanism Ys, in which the main mechanism X and the opening / closing mechanism Ys are assembled and which has the rotational movement conversion mechanism MDs and the rotation restricting mechanism MR, will be described with reference to Figure 13. Note that Figure 13 is illustrated in the same direction as Figure 10.

[0169] 13(a) to (c) show the open valve state in which the valve stem 40 has been rotated the most counterclockwise, FIGS. 13(d) to (f) show the state in which the valve stem 40 has been rotated 90 degrees clockwise from the open valve state, FIGS. 13(g) to (i) show the state in which the valve stem 40 has been rotated 135 degrees clockwise from the open valve state, and FIGS. 13(j) to (l) show the state in which the valve stem 40 has been rotated 180 degrees clockwise from the open valve state, i.e., the closed valve state in which the valve stem 40 has been rotated the most clockwise.

[0170] In other words, the butterfly valve 1 equipped with the opening / closing mechanism Ys can be switched from an open state in which the valve stem 40 is rotated the most counterclockwise to a closed state in which the valve stem 40 is rotated the most clockwise by rotating it 180 degrees.

[0171] The operation of the butterfly valve 1 equipped with the opening / closing mechanism Ys from the initial state of the open valve state shown in Figures 13(a) to 13(c) to the closed valve state shown in Figures 13(j) to 13(l), more specifically, the operation of the rotational movement conversion mechanism MDs, the rotation restriction mechanism MR, and the valve body 50 from the open valve state to the closed valve state, will be described below.

[0172] The open state of the opening / closing mechanism Ys, which is referred to as the initial state in this specification, is the same as the open state of the opening / closing mechanism Y, and therefore a description thereof will be omitted. The rotation restriction mechanism MR at this time is also the same as the rotation restriction mechanism MR in the open state of the opening / closing mechanism Y, and therefore a description thereof will be omitted.

[0173] In the open valve state, rotation is not restricted by the rotation restriction mechanism MR, so when the valve stem 40 is rotated clockwise by a predetermined angle of 90 degrees from the open valve state, the cam 80s and cam link 90 rotate clockwise by 90 degrees in conjunction with the clockwise rotation of the valve stem 40 (see Figure 13 (e)).

[0174] Furthermore, the boundary between the second arcuate portion 85s and the third arcuate portion 86s of the cam 80s abuts against the front inner surface 542s of the cam groove 54s, the first linear portion 82s abuts against the rear inner surface 543s of the cam groove 54s, and the third linear portion 87s abuts against the inner surface of the left side WL of the cam groove 54s. As a result, the push-in base 51s also rotates 90 degrees clockwise as the valve stem 40 and cam 80s rotate (see FIGS. 13(d), 13(e), and 13(f)). Therefore, the valve disc 50 attached to the vertical portion 52 of the push-in base 51s faces the front side DF, but there is a gap between the valve disc 50 and the seat ring 20 attached to the attachment portion 111, and the valve disc 50 is not sealed (see FIG. 13(f)).

[0175] 13(d), 13(g), and 13(h), the frame opening 632 is disposed on the front side DF of the convex portion 71 whose long axis direction is oriented along the depth direction D, and movement of the front side DF of the convex portion 71 is permitted. In other words, when the valve stem 40 is rotated clockwise to a position of 90 degrees from the initial state, the rotation restriction mechanism MR restricts further rotation of the convex portion 71, but functions as a movement direction restriction means that permits movement of the convex portion 71 to the front side DF.

[0176] Then, when the valve stem 40 is further rotated to the 135-degree position, the cam 80s and the cam link 90 also rotate to the 135-degree position (see FIGS. 13(g), 13(h), and 13(i)). However, even if the cam 80s and the cam link 90 rotate, the push-in base 51s to which the valve body 50 is attached and the guide 70 do not rotate because the side surface of the convex portion 71 abuts against the circular side frame 634, as shown in FIG. 13(d), and the rotation restriction mechanism MR restricts further clockwise rotation of the convex portion 71 (see FIG. 13(g)).

[0177] In this way, when the valve stem 40 rotates beyond the predetermined angle of 90 degrees, the cam 80s rotates clockwise relative to the cam groove 54s provided in the push-in base 51s, the arc-shaped portions 85s and 88s of the cam 80s move the push-in base 51s toward the front side DF.

[0178] In detail, as described above, in the second arc-shaped portion 85s that abuts against the front inner surface 542s of the cam groove 54s, the distance from the first center Fc gradually increases from the boundary with the third arc-shaped portion 86s toward the boundary with the second arc-shaped portion 85s, and in the fourth arc-shaped portion 88s that abuts against the rear inner surface 543s of the cam groove 54s, the distance from the first center Fc gradually decreases from the boundary with the first straight portion 82s toward the boundary with the third straight portion 87s.

[0179] As a result, the distance between the first center Fc and the point at which the second arc-shaped portion 85s abuts against the front inner surface 542s of the cam groove 54s gradually increases, and the front inner surface 542s of the cam groove 54s is pushed toward the front side DF by the second arc-shaped portion 85s rotating clockwise. On the other hand, the distance between the first center Fc and the point at which the fourth arc-shaped portion 88s abuts against the rear inner surface 543s of the cam groove 54s gradually decreases. In other words, the fourth arc-shaped portion 88s approaches the first center Fc.

[0180] At this time, the long axis direction of the through hole 73 of the guide 70 is oriented along the depth direction D, and the convex portion 71 can move relative to the valve rod 40 toward the front side DF through the frame opening 632 of the rotation restriction groove 63 (see Figure 13 (g)).

[0181] Therefore, when the valve stem 40 rotates beyond the predetermined angle of 90 degrees, causing the cam 80s to rotate clockwise relative to the cam groove 54s provided in the push-in base 51s, the second arc-shaped portion 85s of the cam 80s pushes the front inner surface 542s of the cam groove 54s toward the front side DF, and the push-in base 51s moves to the front side DF. Furthermore, the length of the imaginary line VL passing through the second center Sc and connecting any point on the second arc-shaped portion 85s and any point on the fourth arc-shaped portion 88s is set to be equal to the depth length DL of the cam groove 54s. Therefore, even if the valve rod 40 rotates beyond the specified angle of 90 degrees, the front inner surface 542s of the cam groove 54s and the second arc-shaped portion 85s abut, and the rear inner surface 543s of the cam groove 54s and the fourth arc-shaped portion 88s rotate in abutting contact. In other words, the push-in base 51s can be moved to the front side DF without creating a gap between the cam 80s and the abutting surface 541s of the cam groove 54s in the depth direction D.

[0182] In this state, when the valve rod 40 is further rotated to the 180-degree position, the cam 80s and cam link 90 also rotate to the 180-degree position (see Figure 13(l)), but the push-in base 51s in which the base portion 72 is positioned in the placement groove 55 does not rotate (see Figure 13(j)).As described above, the push-in base 51s to which the valve body 50 is attached moves to the front side DF, and the valve body 50 comes into close contact with the seat ring 20 attached to the attachment portion 111, thereby sealing the flow opening 112.

[0183] At this time, the over-rotation prevention bolt 95 attached to the horizontal arm 91 of the cam link 90 abuts against the vertical portion 52, restricting further clockwise relative rotation of the cam link 90 with respect to the push-in base 51s.

[0184] In this way, the valve stem 40 is rotated clockwise from the initial open state to a position of 180 degrees to enter the closed state, but the valve can be opened by rotating the valve stem 40 counterclockwise from this closed state to a position of 180 degrees.

[0185] Specifically, when the valve rod 40 is rotated counterclockwise to a predetermined angle of 90 degrees, the cam 80s and cam link 90 also rotate counterclockwise by 90 degrees, but the push-in base 51 does not rotate. Therefore, when the cam 80s rotates counterclockwise relative to the cam groove 54s provided in the push-in base 51s, the fourth arc-shaped portion 88s of the cam 80s pushes the inner rear surface 543s of the cam groove 54s toward the rear DB, and the push-in base 51s moves to the rear DB.

[0186] Furthermore, the length of the imaginary line VL passing through the second center Sc and connecting any point on the second arc-shaped portion 85s and any point on the fourth arc-shaped portion 88s is set to be equal to the depth length DL of the cam groove 54s. Therefore, even when the valve rod 40 rotates counterclockwise from the closed valve state, the rear inner surface 543s of the cam groove 54s and the fourth arc-shaped portion 88s abut, and the front inner surface 542s of the cam groove 54s and the second arc-shaped portion 85s rotate in abutting contact. In other words, the push-in base 51s can be moved to the rear side DB without creating a gap between the cam 80s and the abutting surface 541s of the cam groove 54s in the depth direction D.

[0187] In other words, the cam 80s rotates counterclockwise by 90 degrees in the cam groove 54s, and the push-in base 51 moves to the rear DB, i.e., the valve body 50 is pulled into the rear DB, so that the valve body 50 is no longer in close contact with the seat ring 20.

[0188] When the valve stem 40 is further rotated counterclockwise to the 180-degree position, i.e., to the valve open position, the cam 80s and cam link 90 also rotate counterclockwise to the 180-degree position, i.e., to the valve open position, in conjunction with the rotation of the valve stem 40. Then, in conjunction with the rotation of the cam 80s and cam link 90, the push-in base 51s and guide 70 to which the valve disc 50 is attached also rotate counterclockwise to the 180-degree position, i.e., to the valve open position, thereby entering the valve open state.

[0189] As described above, the butterfly valve 1 equipped with the opening / closing mechanism Ys exhibits the following effects in addition to the effects exhibited by the butterfly valve 1 equipped with the opening / closing mechanism Y. Specifically, the butterfly valve 1 equipped with the opening / closing mechanism Ys includes a valve box 10 having a tubular flow path F, a valve stem 40 rotatably mounted on the valve box 10, a valve disc 50 that is rotated by the valve stem 40 to open and close the flow path F, and a seat ring 20 mounted between the valve box 10 and the valve disc 50. A rotation-movement conversion mechanism MDs is provided between the valve stem 40 and the valve disc 50, which rotates the valve disc 50 as the valve stem 40 rotates from the valve open position up to 90 degrees, and which moves the valve disc 50 so as to come into close contact with the seat ring 20 when the valve stem 40 rotates more than 90 degrees. The direction in which the rotational movement conversion mechanism MDs moves the valve body 50 so that it is in close contact with the seat ring 20 is the front side DF, and the opposite direction is the back side DB.The rotational movement conversion mechanism MDs is provided with a cam 80s provided on the valve stem 40 and a cam groove 54s provided on a push-in base 51 integrated with the valve body 50, into which the cam 80s fits.The cam groove 54s has an abutment surface 541s on the front side DF, separated by a depth length DL, and the cam 80s is provided with two arc-shaped portions 85s, 88s, which are arc-shaped about a second center Sc that is eccentric with respect to a first center Fc, which is the center of rotation of the valve stem 40. The two arc-shaped portions 85s, 88s are arranged in opposing directions across the second center Sc, and the length of the imaginary line VL connecting the two arc-shaped portions 85s, 88s passing through the second center Sc is set to be equal to the depth length DL. When the valve rod 40 rotates more than 90 degrees, the abutment surface 541s, which is arranged in the cam groove 54s and separated by the depth length DL, abuts against the two arc-shaped portions 85s, 88s, and the valve body 50 moves from the first center Fc of the valve rod 40 along the flow path F so as to be in close contact with the seat ring 20.

[0190] In more detail, the rotation-movement conversion mechanism MDs in the butterfly valve 1, which rotates the valve disc 50 using the valve stem 40 and brings the valve disc 50 into contact with the seat ring 20 to open or close the flow path F in the valve body 10, rotates the valve disc 50 as the valve stem 40 rotates from the open position up to 90 degrees, and moves the valve disc 50 so that it comes into close contact with the seat ring 20 when the valve stem 40 rotates beyond 90 degrees.

[0191] The rotational movement conversion mechanism MDs also includes a cam 80s provided on the valve stem 40 and a cam groove 54s provided on the push-in base 51 integrated with the valve disc 50. The cam groove 54s fits into the cam 80s and has an abutment surface 541s separated by a depth length DL in the depth direction D. The cam 80s includes two arc-shaped portions 85s, 88s that are arc-shaped about a second center Sc that is eccentric with respect to a first center Fc that serves as the rotation center of the valve stem 40. The two arc-shaped portions 85s, 88s are arranged facing each other across the second center Sc, and the length of an imaginary line VL connecting the two arc-shaped portions 85s, 88s and passing through the second center Sc is set to be equal to the depth length DL.

[0192] In the rotational movement conversion mechanism MDs, which is thus configured with the cam 80s and cam groove 54s, when the valve stem 40 rotates more than 90 degrees, the cam 80s rotates relative to the cam groove 54s, and the abutment surface 541s, which is arranged in the cam groove 54s at a distance of a depth length DL, abuts against the two arc-shaped portions 85s and 88s, and the valve body 50 moves from the first center Fc of the valve stem 40 along the flow path F so as to be in close contact with the seat ring 20.

[0193] Therefore, in the closed valve state, the valve element 50 and the seat ring 20 are in close contact with each other under high compressive surface pressure, so that even when blocking the flow of a fluid with a small molecular size or a fluid at an extremely low temperature, such as a cryogenic temperature, the fluid does not leak out from between the seat ring 20 and the valve element 50, and the flow path F can be reliably blocked.

[0194] The contact surfaces 541s in the cam groove 54s are spaced apart by the depth length DL, and the two arc-shaped portions 85s, 88s, which are arranged facing each other across the second center Sc, are configured so that the length of an imaginary line VL connecting the two arc-shaped portions 85s, 88s and passing through the second center Sc is equal to the depth length DL. Therefore, when the cam 80s rotates relative to the cam groove 54s, no play occurs between the contact surfaces 541s and the two arc-shaped portions 85s, 88s, which are spaced apart by the depth length DL. Therefore, by rotating the valve stem 40 more than 90 degrees, the valve disc 50 can be moved stably from the first center Fc of the valve stem 40 along the flow path F so as to come into close contact with the seat ring 20.

[0195] In addition, the two arc-shaped portions 85s, 88s have different diameters, and are arranged in opposing directions across the second center Sc. The length of the imaginary line VL connecting the second arc-shaped portion 85s and the fourth arc-shaped portion 88s, which passes through the second center Sc, is set to be equal to the depth length DL. When the valve rod 40 rotates more than 90 degrees, the arc-shaped portions 85s, 88s abut against the abutment surface 541s, which is arranged in the cam groove 54s across the depth length DL.

[0196] Therefore, the valve body 50 can be reliably abutted against the abutting surface 541s even in various states depending on the eccentricity direction and amount of eccentricity of the second center Sc relative to the first center Fc, and can be moved from the first center Fc of the valve rod 40 along the flow path F so as to be in close contact with the seat ring 20.

[0197] Furthermore, when the valve stem 40 is rotated 90 degrees, the second center Sc is eccentric to the rear side DB relative to the first center Fc, the second arc-shaped portion 85s is positioned on the front side DF relative to the second center Sc, and the fourth arc-shaped portion 88s is positioned on the rear side DB relative to the second center Sc.

[0198] Therefore, even when the opening-closing mechanism Ys has its second center Sc eccentric to the rear side DB relative to the first center Fc when rotated 90 degrees, the second arc-shaped portion 85s disposed on the front side DF relative to the second center Sc and the fourth arc-shaped portion 88s disposed on the rear side DB relative to the second center Sc abut against the abutment surface 541s, thereby moving the valve disc 50 from the first center Fc of the valve stem 40 along the flow path F so as to come into close contact with the seat ring 20. Furthermore, even when the valve disc 50 is rotated in the reverse direction, the abutment surface 541s causes the valve disc 50, which is in close contact with the seat ring 20, to be moved away from the abutment surface 541s along the flow path F toward the rear side DB.

[0199] In addition, a rotation restriction mechanism MR is provided which allows the valve body 50 to rotate up to 90 degrees from the open position of the valve stem 40, restricts the rotation of the valve body 50 associated with rotation of the valve stem 40 beyond 90 degrees, and allows the valve body 50 to move in a direction that brings it into close contact with the seat ring 20.

[0200] Therefore, while the rotation restriction mechanism MR restricts rotation of the valve disc 50 that accompanies rotation of the valve stem 40 exceeding 90 degrees, the rotation movement conversion mechanism MDs moves the valve disc 50 in a direction that brings it into close contact with the seat ring 20 in the closed valve state, thereby reliably blocking the flow path F. Furthermore, although the cam groove 54s is formed so that its width direction W is wider than its depth length DL in the depth direction D, the rotation restriction mechanism MR can prevent the push-in base 51s from unintentionally shifting in the width direction W.

[0201] In addition, the abutment surface 541s provided in the cam groove 54s is formed by surfaces (542s, 543s) extending in the width direction W, and the cam 80s is provided with a first straight portion 82s that comes into surface contact with the rear inner surface 543s (541s) in the open valve state, and a second straight portion 84s that comes into surface contact with the front inner surface 542s (541s) in the closed valve state.

[0202] Therefore, in the open state, the first straight portion 82s of the cam 80s comes into surface contact with the rear inner surface 543s (541s) formed by a surface extending in the width direction W on the rear side DB, and in the closed state, the second straight portion 84s of the cam 80s comes into surface contact with the front inner surface 542s (541s) formed by a surface extending in the width direction W on the front side DF, so that each state can be stably maintained. Note that, because the first straight portion 82s and the second straight portion 84s come into surface contact with the abutted surface 541s, excessive rotation of the valve stem 40 beyond the surface contact state can be prevented.

[0203] Next, a further embodiment of the present invention will be described with reference to the drawings. Figure 14 shows an explanatory diagram of a rotational movement conversion mechanism MDt according to another embodiment, and Figure 15 shows an explanatory diagram of the opening and closing operation of a butterfly valve 1 having an opening and closing mechanism Yt according to another embodiment.

[0204] 14(a) to 14(c) show views corresponding to FIGS. 13(a) to 13(c) of a butterfly valve 1 having an opening / closing mechanism Yt in an open state. FIGS. 15(a) to 15(l) show views corresponding to FIGS. 13(a) to 13(l) of a butterfly valve 1 having an opening / closing mechanism Yt. Note that in the above-mentioned drawings, the same components in the butterfly valve 1 having the opening / closing mechanism Yt as those in the butterfly valve 1 having the opening / closing mechanism Y or the opening / closing mechanism Ys are designated by the same reference numerals, and descriptions thereof will be omitted.

[0205] The opening and closing mechanism Yt in the butterfly valve 1 is the same as the opening and closing mechanism Ys except for the cams 80s and 80t in the opening and closing mechanism Ys described above, and the cam 80t will be described below.

[0206] As described above, in the open valve state shown in Figure 14 (b), cam 80s has a first straight portion 82s, a first arc-shaped portion 83s, a second straight portion 84s, a second arc-shaped portion 85s, a third arc-shaped portion 86s, a third straight portion 87s, and a fourth arc-shaped portion 88s, which are arranged in this order in a plan view clockwise from the rear DB, whereas cam 80t has a planar shape in which the second straight portion 84s, the first arc-shaped portion 83s, the first straight portion 82s, the fourth arc-shaped portion 88s, the third straight portion 87s, the third arc-shaped portion 86s, and the second arc-shaped portion 85s are arranged in this order in a plan view clockwise from the rear DB. In other words, the cam 80t in the open state shown in Figure 14(c) is oriented in the reverse direction of the cam 80s in the open state shown in Figure 11(c) with respect to the 45-degree diagonal imaginary line VL2 (see Figure 14(a)) connecting the left side WL and the front side DF with the right side WR and the rear side DB.

[0207] Therefore, as shown in Figure 14 (b), in cam 80s, the second center Sc is eccentric to the rear side DB of the first center Fc, while the second center Sc in cam 80t is positioned to the right side WR of the first center Fc.

[0208] In addition, the opening / closing mechanism Yt having a push-in base 51s with a cam groove 54s and a cam 80t positions the cam 80t in the cam groove 54s, which is formed in a roughly rectangular shape in a plan view with the width direction W wider than the depth direction D, so that the second straight portion 84s is on the rear side DB, the first straight portion 82s is on the right side WR, and the third straight portion 87s is on the front side DF.

[0209] At this time, the second straight portion 84s of the cam 80t abuts against a rear inner side surface 543s of the cam groove 54s, which is formed in a generally rectangular shape in plan view with a width direction W wider than a depth direction D, and the third straight portion 87s abuts against a front inner side surface 542s of the cam groove 54s. In addition, the boundary between the second arc-shaped portion 85s and the third arc-shaped portion 86s abuts against the inner side surface of the left side WL of the cam groove 54s.

[0210] The second straight portion 84s and the third straight portion 87s, which are formed linearly in a plan view, are in face-to-face contact with the contact surface 541s of the cam groove 54s in the depth direction D. In addition, when a portion of the cam 80s is in contact with the contact surface 541s of the cam groove 54s, this may mean that the portion is actually in contact with the contact surface 541s, or that a gap equivalent to a tolerance exists.

[0211] Next, the case where the valve rod 40 in the opening / closing mechanism Yt is rotated beyond a predetermined angle will be described below. Note that the operation of the opening / closing mechanism Yt until the valve rod 40 exceeds the predetermined angle of 90 degrees is the same as the operation of the opening / closing mechanisms Y and Ys described above, and therefore the explanation will be omitted.

[0212] 15(a) to (c) show the open valve state in which the valve stem 40 has been rotated the most counterclockwise, FIGS. 15(d) to (f) show the state in which the valve stem 40 has been rotated 90 degrees clockwise from the open valve state, FIGS. 15(g) to (i) show the state in which the valve stem 40 has been rotated 135 degrees clockwise from the open valve state, and FIGS. 15(j) to (l) show the state in which the valve stem 40 has been rotated 180 degrees clockwise from the open valve state, that is, the closed valve state in which the valve stem 40 has been rotated the most clockwise.

[0213] In this way, the butterfly valve 1 having the opening and closing mechanism Yt can be switched from an open state in which the valve stem 40 is rotated the most counterclockwise to a closed state in which the valve stem 40 is rotated the most clockwise by rotating it 180 degrees.

[0214] 15(b), the third straight portion 87s and the second straight portion 84s of the cam 80t abut against the abutment surfaces 541s (542s, 543s) on both sides of the cam groove 54s in the depth direction D. Therefore, when the valve stem 40 rotates up to the predetermined angle of 90 degrees, the cam 80t and the cam link 90 also rotate together with the push-in base 51s.

[0215] When the valve stem 40 is rotated clockwise from the open state beyond a predetermined angle of 90 degrees, for example, to a position of 135 degrees, the cam 80t and cam link 90 also rotate to the 135 degree position (see Figures 15(g), (h), and (i)), but the push-in base 51s and guide 70 are prevented from further clockwise rotation by the rotation restriction mechanism MR and do not rotate (see Figure 15(g)).

[0216] In this way, when the valve stem 40 rotates beyond the predetermined angle of 90 degrees, the cam 80t rotates clockwise relative to the cam groove 54s provided in the push-in base 51s, the second arc-shaped portion 85s and the fourth arc-shaped portion 88s of the cam 80t move the push-in base 51s toward the front side DF.

[0217] In detail, as described above, in the fourth arc-shaped portion 88s that abuts against the front inner surface 542s of the cam groove 54s, the distance from the first center Fc gradually increases from the boundary with the third straight portion 87s toward the boundary with the first straight portion 82s, and in the second straight portion 84s that abuts against the rear inner surface 543s of the cam groove 54s, the distance from the first center Fc gradually decreases from the boundary with the second straight portion 84s toward the boundary with the third arc-shaped portion 86s.

[0218] As a result, the distance between the first center Fc and the point at which the fourth arc-shaped portion 88s of the cam groove 54s abuts against the front inner surface 542s gradually increases, and the front inner surface 542s of the cam groove 54s is pushed toward the front side DF by the fourth arc-shaped portion 88s rotating clockwise. On the other hand, the distance between the first center Fc and the point at which the second arc-shaped portion 85s of the cam groove 54s abuts against the rear inner surface 543s of the cam groove 54s gradually decreases, that is, the cam groove 54s approaches the first center Fc.

[0219] At this time, the long axis direction of the through hole 73 of the guide 70 is oriented along the depth direction D, and the convex portion 71 can move relative to the valve rod 40 toward the front side DF through the frame opening 632 of the rotation restriction groove 63 (see Figure 15 (g)).

[0220] Therefore, when the valve stem 40 rotates beyond the predetermined angle of 90 degrees, causing the cam 80t to rotate clockwise relative to the cam groove 54s provided in the push-in base 51s, the fourth arc-shaped portion 88s of the cam 80t pushes the front inner surface 542s of the cam groove 54s toward the front side DF, and the push-in base 51s moves to the front side DF. Furthermore, the length of the imaginary line VL passing through the second center Sc and connecting any point on the fourth arc-shaped portion 88s and any point on the second arc-shaped portion 85s is set to be equal to the depth length DL of the cam groove 54s.Therefore, even if the valve rod 40 rotates beyond the specified angle of 90 degrees, the front inner surface 542s of the cam groove 54s and the fourth arc-shaped portion 88s abut, and the rear inner surface 543s of the cam groove 54s and the second arc-shaped portion 85s rotate in abutting contact.In other words, the push-in base 51s can be moved to the front side DF without creating a gap between the cam 80t and the abutting surface 541s of the cam groove 54s in the depth direction D.

[0221] In this state, when the valve rod 40 is further rotated to the 180 degree position, the cam 80t and the cam link 90 rotate to the 180 degree position (see Figure 15(l)), but the push-in base 51s in which the base portion 72 is positioned in the placement groove 55 does not rotate (see Figure 15(j)). As described above, the push-in base 51s to which the valve body 50 is attached moves to the front side DF, and the valve body 50 comes into close contact with the seat ring 20 attached to the attachment portion 111, thereby sealing the flow opening 112.

[0222] Furthermore, when the valve rod 40 is rotated counterclockwise to a predetermined angle of 90 degrees, the cam 80t and cam link 90 rotate counterclockwise by 90 degrees, but the push-in base 51 does not rotate, so the second arc-shaped portion 85s of the cam 80t pushes the inner rear surface 543s of the cam groove 54s toward the rear DB, and the push-in base 51s moves to the rear DB.

[0223] Furthermore, the length of the imaginary line VL passing through the second center Sc and connecting any point on the fourth arc-shaped portion 88s and any point on the second arc-shaped portion 85s is set to be equal to the depth length DL of the cam groove 54s.Therefore, even when the valve rod 40 rotates counterclockwise from the closed valve state, the rear inner surface 543s of the cam groove 54s and the second arc-shaped portion 85s abut, and the front inner surface 542s of the cam groove 54s and the fourth arc-shaped portion 88s rotate in abutting contact.In other words, the push-in base 51s can be moved to the rear side DB without creating a gap between the cam 80t and the abutting surface 541s of the cam groove 54s in the depth direction D.

[0224] In other words, the cam 80s rotates counterclockwise by 90 degrees in the cam groove 54s, and the push-in base 51 moves to the rear DB, i.e., the valve body 50 is pulled into the rear DB, so that the valve body 50 is no longer in close contact with the seat ring 20.

[0225] When the valve stem 40 is further rotated counterclockwise to the 180-degree position, i.e., to the valve open position, the cam 80t and the cam link 90 also rotate counterclockwise to the 180-degree position, i.e., to the valve open position, in conjunction with the rotation of the valve stem 40. Then, in conjunction with the rotation of the cam 80t and the cam link 90, the push-in base 51s and the guide 70 to which the valve disc 50 is attached also rotate counterclockwise to the 180-degree position, i.e., to the valve open position, thereby entering the valve open state.

[0226] As described above, the butterfly valve 1 equipped with the opening / closing mechanism Yt exhibits the following advantageous effects in addition to the advantageous effects exhibited by the butterfly valve 1 equipped with the opening / closing mechanism Y and the butterfly valve 1 equipped with the opening / closing mechanism Ys. Specifically, when the valve stem 40 is rotated 90 degrees, the second center Sc is eccentric to the front side DF and to the right side WR with respect to the first center Fc, the second arc-shaped portion 85s is disposed on the rear side DB side and on the left side WL with respect to the second center Sc, and the fourth arc-shaped portion 88s is disposed on the front side DF side and to the right side WR with respect to the second center Sc.

[0227] Therefore, even when the opening / closing mechanism Yt has its second center Sc eccentric to the front side DF and the right side WR relative to the first center Fc when rotated 90 degrees, the second arc-shaped portion 85s, which is disposed on the rear side DB side and on the left side WL relative to the second center Sc, and the fourth arc-shaped portion 88s, which is disposed on the front side DF side and on the right side WR relative to the second center Sc, abut against the abutment surface 541s, and the valve disc 50 can be moved from the first center Fc of the stem 40 along the flow path F so as to be in close contact with the seat ring 20. Even during rotation in the opposite direction, the valve disc 50, which abuts against the abutment surface 541s and is in close contact with the seat ring 20, can be moved along the flow path F toward the rear side DB.

[0228] As described above, in the correspondence between the configuration of the present invention and the above-mentioned embodiments, the flow path of the present invention corresponds to the flow path F, and similarly below, the valve body corresponds to the valve body 10, the valve stem corresponds to the valve stem 40, the valve disc corresponds to the valve disc 50, the seat ring corresponds to the seat ring 20, the rotational movement conversion mechanism corresponds to the rotational movement conversion mechanisms MD, MDs, MDt, the cam body corresponds to the cams 80, 80s, 80t, the cam groove corresponds to the cam grooves 54, 54s, the butterfly valve corresponds to the butterfly valve 1, the predetermined angle corresponds to 45 degrees or 90 degrees, the pushing direction corresponds to the front side DF, the recess corresponds to the large arc-shaped portion 543, the pushing surface corresponds to the straight portion 542, the rotation restricting mechanism corresponds to the rotation restricting mechanism MR, the axial direction corresponds to the height direction H, the transmission member corresponds to the cam link 90, the offset portion corresponds to the horizontal arm 91 and the vertical connecting portion 92, the over-rotation restricting portion corresponds to the over-rotation prevention bolt 95, the predetermined angle corresponds to 90 degrees, the moving direction corresponds to the front side DF, the opposite moving direction corresponds to the rear side DB, the abutted portion corresponds to the abutted surface 541s, the axis corresponds to the first center Fc, the eccentric center corresponds to the second center Sc, the arc-shaped portion corresponds to the second arc-shaped portion 85s and the fourth arc-shaped portion 88s, the imaginary line corresponds to the imaginary line VL, the predetermined interval corresponds to the depth length DL, the large diameter arc-shaped portion corresponds to the second arc-shaped portion 85s, the small diameter arc-shaped portion corresponds to the fourth arc-shaped portion 88s, the orthogonal direction corresponds to the width direction W, the side opposite to the side where the eccentric center is located corresponds to the left side WL, the side where the eccentric center is located corresponds to the right side WR, the valve-opening abutment surface corresponds to the first straight portion 82s, The valve-closing contact surface corresponds to the second straight portion 84s, but is not limited to this in the above embodiment.

[0229] For example, the butterfly valve 1 having the above-described opening / closing mechanisms Y, Ys, and Yt was a central butterfly valve, but it may also be configured as a primary eccentric butterfly valve or a secondary eccentric butterfly valve. Also, in the above explanation, the butterfly valve 1 having the opening / closing mechanism Y was provided with a rotational movement conversion mechanism MD and a rotation restriction mechanism MR to achieve the above-described operation, but it may also be provided without a rotation restriction mechanism MR, and the valve stem 40 may be rotated to a 90-degree position to cause the valve element 50 and seat ring 20 to come into contact with each other, thereby causing the valve to rotate using a rotational load.

[0230] In this case, without providing a rotation restriction mechanism MR, rotation of the valve disc 50 accompanying clockwise rotation of the valve stem 40 exceeding 90 degrees can be restricted, and in the closed state, the valve disc 50 can be moved to the front side DF by the rotation movement conversion mechanism MD, thereby reliably blocking the flow path F. Therefore, it is possible to configure a butterfly valve 1 having an opening / closing mechanism Y with a simpler structure than when a rotation restriction mechanism MR is provided.

[0231] Furthermore, in the description of the butterfly valve 1 having the opening / closing mechanism Y described above, the valve stem 40 is rotated clockwise from the initial open state to a position of 45 degrees to restrict the relative rotation of the convex portion 71 by the rotation restriction mechanism MR, and when rotation exceeds 135 degrees, the straight portion 542 of the cam groove 54s in the arc-shaped portion 84 is pressed against the valve body 50 to move it toward the front side DF and make it adhere to the seat ring 20, but the angle is not limited to the above and may be set to any appropriate angle.

[0232] Alternatively, the convex portion 71 may be rotated to a 90-degree position to restrict the relative rotation of the rotation restriction mechanism MR, and when the rotation exceeds 90 degrees, the straight portion 542 of the cam groove 54s at the arc-shaped portion 84 is pressed against the valve body 50 to move it toward the front side DF and bring it into close contact with the seat ring 20.

[0233] Furthermore, the shape of the rotation restriction groove 63 in the rotation restriction mechanism MR is not limited to the above-mentioned shape, and for example, the arc frame 633 may be formed circumferentially, and the frame opening 632 may not be an opening but a recess provided in the circumferential arc frame 633, and the circular side frame 634 that restricts the rotation of the convex portion 71 may also be composed of a convex portion protruding from the inner surface of the circumferential arc frame 633.

[0234] The valve stem 40 includes a valve stem 40A and a valve stem 40B, and uses a cam link 90 to transmit the rotation of the valve stem 40A to the rotational movement conversion mechanisms MD, MDs, MDt on the lower HD and the rotation restriction mechanism MR. However, the valve stem 40 may be configured with a single valve stem 40 that penetrates the push-in bases 51, 51s, 51t in the height direction H. In this case, the cam link 90 is unnecessary, but like the cam link 90, the valve stem 40 may be provided with a biasing portion that shifts in a predetermined direction from the axis in the portion of the valve stem 40 located between the horizontal portions 53, 53s, 53t of the push-in bases 51, 51s, 51t.

[0235] Furthermore, in the above explanation, the rotational movement conversion mechanisms MD, MDs, MDt move the valve body 50 in the direction in which the fluid flows from the rear side DB toward the front side DF, that is, toward the front side DF, and make it adhere to the seat ring 20. However, the direction in which the rotational movement conversion mechanisms MD, MDs, MDt move the valve body 50 does not have to be along the direction of the fluid flow, and the direction in which the valve body 50 adheres to the seat ring 20 may be a direction that intersects the direction of the fluid flow.

[0236] Furthermore, in the above explanation, in the rotational movement conversion mechanisms MD, MDs, MDt, the cams 80, 80s, 80t are connected to the valve stem 40, and the cam grooves 54, 54s are provided in the push-in bases 51, 51s, 51t to which the valve body 50 is attached, but it is also possible to provide a cam groove in the valve stem 40 and provide a cam in the push-in bases 51, 51s, 51t to which the valve body 50 is attached.

[0237] Furthermore, in the above description, the butterfly valve 1 having the opening and closing mechanisms Y, Ys, Yt is configured to be able to switch from an open state in which the valve stem 40 is rotated fully counterclockwise to a closed state in which the valve stem 40 is rotated fully clockwise by rotating it 180 degrees, but the butterfly valve 1 having the opening and closing mechanisms Y, Ys, Yt may also be configured to switch from an open state to a closed state by rotating the valve stem 40 counterclockwise.

[0238] In the case of the above-described opening / closing mechanisms Ys and Yt, it is not necessary to provide the over-rotation prevention bolt 95 provided on the hook portion 94 of the cam link 90 or the hook portion 94 itself. Specifically, in the opening / closing mechanism Ys, the first straight portion 82s and the third straight portion 87s abut against the abutment surface 541s of the cam groove 54s in the valve open state, and the second straight portion 84s and the third straight portion 87s abut against the abutment surface 541s of the cam groove 54s in the valve closed state, so that each state can be stably maintained.

[0239] Furthermore, the length of the imaginary line VL connecting the boundary between the first arc-shaped portion 83s of the first straight portion 82s, which abuts the rear inner surface 543s of the cam groove 54 in the open state, and a point on the third arc-shaped portion 86s passing through the first center Fc, and the length of the imaginary line VL connecting the boundary between the first arc-shaped portion 83s of the second arc-shaped portion 85s, which abuts the front inner surface 542s of the cam groove 54 in the closed state, and a point on the third arc-shaped portion 86s passing through the first center Fc, are the longest on the cam 80s, so that excessive rotation of the valve rod 40 about the first center Fc can be prevented.

[0240] Furthermore, the length of the imaginary line VL connecting the boundary between the first arc-shaped portion 83s of the second straight portion 84s, which abuts the rear inner surface 543s of the cam groove 54 in the open state, and a point on the third arc-shaped portion 86s passing through the first center Fc, and the length of the imaginary line VL connecting the boundary between the first arc-shaped portion 83s of the first straight portion 82s, which abuts the front inner surface 542s of the cam groove 54 in the closed state, and a point on the third arc-shaped portion 86s passing through the first center Fc, are the longest on the cam 80t, so that excessive rotation of the valve rod 40 about the first center Fc can be prevented.

[0241] Therefore, in the opening and closing mechanisms Ys and Yt, even if an anti-overrotation bolt 95 is not provided on the hook-shaped portion 94 of the cam link 90, and even if the cam link 90 is linear in plan view and does not have a hook-shaped portion 94 in the first place, overrotation around the first center Fc can be prevented.

[0242] The cam groove 54s may have any shape in plan view as long as it has a contact surface 541s on the front side DF separated by the depth length DL and can rotatably fit the cam 80s. While the cam groove 54s includes a planar contact surface 541s separated by the depth length DL, it may also have a convex shape that makes point or line contact with the cams 80s, 80t. The arc shape centered on the second center Sc includes various curved shapes that protrude in a predetermined direction in plan view, such as a circular arc, an elliptical arc, or an oblong arc, and may have an inflection point, for example.

[0243] In the above-described cam 80s having two arc-shaped portions 85s, 88s, each arc-shaped portion having a second center Sc that is eccentric with respect to the first center Fc that is the rotation center of the valve stem 40, the portions other than the arc-shaped portions 85s, 88s may be linear, may be arc-shaped with a center centered on the first center Fc, may be arc-shaped with a center different from the first center Fc and the second center Sc, or may be a combination thereof. Furthermore, the two arc-shaped portions 85s, 88s that are arc-shaped with a center centered on the second center Sc may have different diameters or the same diameter.

[0244] 1...Butterfly valve 10...Valve body 20...Seat ring 40...Valve stem 50...Valve disc 54, 54s...Cam groove 80, 80s, 80t...Cam 82s...First straight portion 84...Arc-shaped portion 84s...Second straight portion 85s...Second arc-shaped portion 88s...Fourth arc-shaped portion 90...Cam link 91...Horizontal arm 92...Vertical connecting portion 96...Over-rotation prevention bolt 541s...Abutting surface 542...Straight portion 543...Large arc-shaped portion DB...Rear side DF...Front side DL...Depth length F...Flow path Fc...First center H...Height direction MD, MDs, MDt...Rotational movement conversion mechanism MR...Rotation restriction mechanism VL...Virtual line W...Width direction WL...Left side WR...Right side Sc...Second center

Claims

1. 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 between the valve stem and the valve disc that rotates the valve disc as the valve stem rotates from its open position to a predetermined angle, and that 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 has a protrusion, some of which has a longer diameter in the circumferential direction than the other parts, and is equipped with a cam body mounted on either the valve stem or the valve disc, and a cam groove mounted on the other of the valve stem or the valve disc and into which the cam body fits; the cam groove is equipped with a recess corresponding to the protrusion, and a pushing surface that is continuous with the recess and is pushed in by the protrusion, When the valve stem rotates beyond the predetermined angle, the convex portion escapes from the concave portion and presses against the pushing surface, moving the valve body from the axis of the valve stem along the flow path so as to be in close contact with the seat ring.

2. A butterfly valve as claimed in claim 1, further comprising a rotation restriction mechanism that allows the valve disc to rotate from the valve open position of the valve stem up to the predetermined angle, restricts the rotation of the valve disc accompanying rotation of the valve stem beyond the predetermined angle, and allows the valve disc to move in a direction that brings it into close contact with the seat ring.

3. A butterfly valve as set forth in claim 2, wherein the rotational movement conversion mechanism and the rotation restriction mechanism are provided on both sides of the valve body in the axial direction along the axis, and a transmission member for transmitting the rotational force of the valve stem is provided to the rotational movement conversion mechanism and the rotation restriction mechanism on the side to which the rotational force is not input from the valve stem, of the rotational movement conversion mechanism and the rotation restriction mechanism provided on both sides of the valve body in the axial direction.

4. A butterfly valve as set forth in claim 3, wherein a portion of the transmission member is provided with an offset portion that is offset in a predetermined direction from the axis center to suppress a decrease in the flow path area when the valve is open.

5. A butterfly valve as set forth in any one of claims 1 to 4, wherein an over-rotation prevention section is provided to prevent over-rotation of the valve stem.

6. The butterfly valve according to claim 1, wherein the valve stem is rotated a predetermined angle to bring the valve body and the seat ring into contact with each other, thereby applying a rotational load to the valve stem.

7. 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 mounted between the valve stem and the valve disc, which rotates the valve disc as the valve stem rotates from its open position to a predetermined angle, and which 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 direction in which the rotational movement conversion mechanism moves the valve disc so as to come into close contact with the seat ring being defined as the movement direction, and the opposite direction as the counter-movement direction, and the rotational movement conversion mechanism comprises: a cam body mounted on either the valve stem or the valve disc; and a cam groove mounted on the other of the valve stem or the valve disc, into which the cam body fits; the cam groove has abutment portions spaced a predetermined distance in the movement direction; and the cam body a butterfly valve comprising at least two arc-shaped portions, each arc-shaped portion having an eccentric center that is eccentric with respect to an axial center that is the center of rotation of the valve stem, the two arc-shaped portions being arranged in opposing directions across the eccentric center, and the length of an imaginary line connecting the two arc-shaped portions and passing through the eccentric center being set to be equal to the predetermined distance, and when the valve stem rotates beyond the predetermined angle, the abutted portions arranged at the predetermined distance in the cam groove abut against the two arc-shaped portions, and the valve disc moves from the axial center along the flow path so as to be in close contact with the seat ring.

8. A butterfly valve as set forth in claim 7, wherein the two arc-shaped portions comprise a large diameter arc-shaped portion and a small diameter arc-shaped portion of different diameters, the large diameter arc-shaped portion and the small diameter arc-shaped portion are arranged facing each other across the eccentric center, and the length of an imaginary line connecting the large diameter arc-shaped portion and the small diameter arc-shaped portion, which passes through the eccentric center, is set to be equal to the specified distance, and when the valve stem rotates beyond the specified angle, the abutted portions arranged at the specified distance in the cam groove abut against the large diameter arc-shaped portion and the small diameter arc-shaped portion.

9. A butterfly valve as set forth in claim 8, wherein the eccentric center is eccentric with respect to the axis in the direction opposite to the movement when the valve stem is rotated by the predetermined angle, the large diameter arc-shaped portion is disposed on the side of the eccentric center in the direction of movement, and the small diameter arc-shaped portion is disposed on the side of the eccentric center in the direction opposite to the movement.

10. A butterfly valve as set forth in claim 8, wherein, when the valve stem is rotated through the predetermined angle, the eccentric center is eccentric relative to the axis in a direction perpendicular to the direction of movement, the large diameter arc-shaped portion is disposed on the side of the eccentric center in the counter-movement direction and opposite to the side on which the eccentric center is disposed, and the small diameter arc-shaped portion is disposed on the side of the eccentric center in the direction of movement and on the side on which the eccentric center is disposed.

11. A butterfly valve as set forth in any one of claims 7 to 10, further comprising a rotation restriction mechanism that allows the valve disc to rotate from the valve open position of the valve stem up to the predetermined angle, restricts the rotation of the valve disc accompanying rotation of the valve stem beyond the predetermined angle, and allows the valve disc to move in a direction that brings it into close contact with the seat ring.

12. A butterfly valve as set forth in claim 11, wherein the abutment portion provided in the cam groove is formed by a surface extending in a direction perpendicular to the movement direction, and the cam body is provided with a valve-open abutment surface that abuts against the abutment portion in the open valve state, and a valve-close abutment surface that abuts against the abutment portion in the closed valve state.

13. A butterfly valve as described in claim 12, wherein the rotational movement conversion mechanism and the rotation restriction mechanism are provided on both sides of the valve body in the axial direction along the axis, and a transmission member for transmitting the rotational force of the valve stem is provided to the rotational movement conversion mechanism and the rotation restriction mechanism on the side to which rotational force is not input from the valve stem, of the rotational movement conversion mechanism and the rotation restriction mechanism provided on both sides of the valve body in the axial direction.

14. A butterfly valve as set forth in claim 13, wherein a portion of the transmission member is provided with an offset portion that is offset in a predetermined direction from the axis center to suppress a decrease in the flow path area when the valve is open.

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