JP6546377B2 - Butterfly valve body and butterfly valve - Google Patents

Description

  The present invention relates to a valve body of a butterfly valve and a butterfly valve, and in particular, a butterfly valve that reduces fluid resistance and operation torque while reducing the weight without losing the strength of the valve body, and is also excellent in sealability and castability. The present invention relates to a valve body and a butterfly valve.

  Generally, the valve body of a butterfly valve is formed in a disk shape, and the valve configuration is such that an elastic seat ring is mounted on the inner peripheral surface of a cylindrical valve body and is rotatably mounted at the diameter position of this main body A disc-like valve body is pivotally supported on the stem, and the valve body is rotated by rotating the stem within a 90 ° range to open and close the flow path. This type of butterfly valve has high sealing performance when fully closed, and is also used as a valve suitable for flow control. Moreover, since the dimension between surfaces can be made small compared with other valve types, the whole valve can be comprised compactly. Furthermore, since the torque is relatively low, the operability is high, and the operation in the 90 ° range is easy to automate. For this reason, it is a highly versatile valve widely used in various forms in various situations such as water supply and drainage, air conditioning equipment, and factory processes.

  By the way, since the butterfly valve is configured as described above, a disc-shaped valve body, which is inclined in a range of 90 ° with respect to the flow direction, is always present in the flow path as the stem rotates. Therefore, when the valve is opened, the valve body reduces the flow passage area, and the step portion or the like formed on the valve body generates turbulent flow to exert resistance on the fluid. When the valve is closed, the fluid exerts a large fluid pressure on the valve body, and the stress based on the fluid pressure may cause a shape change (distortion) in the valve body. This change in shape may damage the valve body, or may cause displacement at the sealing position between the valve body and the elastic seat ring, which may impair sealing performance.

  As means for coping with these problems, there is a means to secure sufficient strength that does not cause shape change by forming the valve body thick, but if it is simply made thick, the strength of the valve body is Although secured, an increase in the operating torque or an increase in the weight of the valve body may lead to a deterioration in manufacturing cost and the like. Therefore, conventionally, for example, the boss and the outer peripheral portion are formed thickly while forming the valve body based on a flat plate as thin as possible, and the weight increase of the valve body and the fluid resistance are suppressed while securing the strength of the valve body. Valve bodies for various types of butterfly valves have been proposed.

  The valve body of the butterfly valve of Patent Document 1 has an outer peripheral portion formed thicker than a flat portion of the valve body, a vertical rib connected to an upper boss portion or a lower boss portion having an insertion hole of the stem, and the vertical rib Since the cross-sectional shape of this reinforcing rib is formed in a square shape or a trapezoidal shape, it has a corner or a step of a sharp curve having a large curvature. have. In addition, since the intersection of the horizontal rib and the vertical rib, and the joint between the outer periphery and the valve plate, etc. are also formed in the rectangular shape with a small radius of curvature, many angular shapes are formed on the valve body surface. ing.

  The valve body of the butterfly valve of Patent Document 2 connects the bosses for the valve rod holes provided by expanding outward in the Y-axis direction of the disc-like valve body in the vertical direction, and connects them with the nozzle side surface and the orifice side. A plurality of lateral ribs of a predetermined height extending in the X-axis direction are provided on the back surface. Also in the valve body of the present invention, the longitudinal rib, the transverse rib, and the like and the flat portion of the valve body have a corner portion or a steep curve step with a small radius of curvature in the cross-sectional shape. Further, unlike the valve body described in the above-mentioned Document 1, the outer peripheral portion of the valve body is not formed thick, and is formed to be as thin as the flat portion of the valve body.

Unexamined-Japanese-Patent No. 2007-32683 JP 2004-239343 A

  However, the valve element of the butterfly valve described in Patent Document 1 has the following problems. First, since the valve body has a thick outer peripheral portion in sliding contact with the elastic seat ring, there is a problem that the operating torque increases because the contact area with the elastic seat ring is large. There is a problem in that surface casting and pitting are more likely to occur when casting aluminum.

  In addition, since the junction between the reinforcing rib and the outer periphery etc. and the flat part of the valve body is a corner or a step of a sharp curve with a small radius of curvature, a large number of square shaped parts are formed on the valve body surface It is done. In a butterfly valve, especially when the valve is fully closed, bending deformation acts on the entire area of the valve blade of the valve body by fluid pressure and strain stress is generated. In this way, in corners and steps formed on the surface of the valve body Since the uniform shape of the member suddenly changes, the stress distribution generated in the entire valve body is disturbed, and there is a problem that the stress is locally concentrated on these corner portions and steps. In the valve body described in Document 1, this stress concentration is remarkable in the vicinity of the intersection of the root portion of the boss portion or the vertical rib or the vertical rib and the horizontal rib, and the width of the horizontal rib in the vicinity of the intersection is narrow. In this case, the concentration of stress is particularly high, which tends to cause deformation of the valve body. Conversely, if the width of the horizontal rib in the vicinity of the intersection portion is increased, the weight of the valve body may be increased more than necessary.

  Furthermore, when a large number of corners and steps are formed on the valve body surface, the flow passage area changes rapidly in the vicinity of these corners and steps, so flow separation from the valve body surface and rapid pressure There is a problem that turbulence and bubbles are easily generated due to the change, and damage to the valve body due to cavitation and instability of fluid control due to turbulence are easily caused.

  In the valve element of the butterfly valve disclosed in Patent Document 2, although the strength of the valve element is improved by forming a plurality of lateral ribs, the strength is high in places without the lateral ribs, particularly when the fluid pressure is high. Because the pressure is low, it is not possible to suppress the occurrence of distortion of the valve body at the time of pressure reception. For this reason, if sufficient strength is to be ensured in the entire valve body, it is impossible to avoid the addition of ribs and the accompanying increase in the weight of the valve body. Therefore, with the valve body disclosed in the present invention, it is extremely impossible to simultaneously achieve securing of the strength of the valve body and weight reduction.

  Further, as in the case of the above-mentioned document 1, a large number of square shaped parts are formed at various places on the surface of the valve body, such as upper and lower bosses, vertical ribs and horizontal ribs. Therefore, even in the valve body described in Document 2, problems such as stress concentration on the angular portion at the time of pressure reception and generation of turbulence and cavitation can not be solved at all.

  Furthermore, the outer peripheral portion of the valve body of the present invention is formed to be as thin as the flat valve plate portion. For this reason, since the rigidity with respect to the fluid pressure of a valve body outer peripheral part runs short, the required intensity | strength of a valve body can not be ensured.

  The present invention has been developed to solve the above-mentioned problems, and the object of the present invention is to ensure the required strength across the entire valve body and the sealing performance of the valve when the valve is closed. A butterfly valve valve that has a surface shape that reduces weight and operating torque for opening and closing the valve, and can suppress local stress concentration on the valve body during pressure reception and the occurrence of turbulent flow and cavitation, and also has excellent castability. In the provision of body and butterfly valves.

In order to achieve the above object, the invention according to claim 1 is a valve body of a butterfly valve provided rotatably in a cylindrical body via an upper and lower stem, and provided on the upper and lower sides of a disc-shaped disc A boss is connected by a longitudinal rib, and a horizontal rib is formed on the front and back surfaces of the disc in a horizontal direction crossing the longitudinal rib, and a cross section cut in a direction perpendicular to the disc of the horizontal rib in the longitudinal rib direction The shape is a flat arc portion consisting of a circular arc having a vertically elongated flat outer diameter, and the flat arc portion is such that the outer diameter of the flat shape is sequentially increased from the outer peripheral side of the disc toward the longitudinal rib side. Is a valve element of a butterfly valve characterized by

In the invention according to claim 2 , the flat arc portion is an elliptical portion, and the elliptical portion is a valve body of a butterfly valve in which a cross-sectional shape cut in the longitudinal rib direction is a longitudinally elongated elliptical portion.

In the invention according to claim 3 , the elliptical portion is a valve body of a butterfly valve formed such that the short side and the long side of the elliptical shape sequentially increase from the outer peripheral side of the disc toward the longitudinal rib side.

In the invention according to claim 4 , the longitudinal rib is a valve element of a butterfly valve having a cylindrical or cylindrical cross section.

The invention according to claim 5 is a valve element of a butterfly valve in which a connecting portion of a longitudinal rib and a horizontal rib, and a connecting portion of a valve plate portion of a disc and a horizontal rib are connected in a rounded shape or an arc shape.

The invention according to claim 6 is a valve element of a butterfly valve in which a ring-shaped thick ring portion is formed in the vicinity of the outer peripheral end of the front and rear surfaces of the disc.

The invention according to claim 7 is a valve element of a butterfly valve in which the thick ring portion and the outer end portion of the horizontal rib are joined in a flat shape.

The invention according to claim 8 is a valve body of a butterfly valve in which the thick-walled cross-sectional shape of the thick ring portion is circular or elliptical.

The invention according to claim 9 is a central butterfly valve in which a valve body of a butterfly valve is provided on an inner periphery of a rubber ring mounted inside a body via upper and lower stems so as to be openable and closable.

  According to the first aspect of the present invention, the longitudinal rib exerts rigidity to suppress bending deformation mainly on the upper and lower stems against the fluid pressure acting on the valve body, and the horizontal rib mainly acts on the center of the valve body. Since the rigidity to suppress the bending deformation with the fulcrum as a supporting point is exhibited, the valve body parts other than these vertical ribs and horizontal ribs are formed thin, and the weight reduction of the valve body is ensured while securing the strength against the fluid pressure of the valve body. Can be Further, the flat arc portion of the horizontal rib has high rigidity against bending deformation acting on the surface of the valve body by the fluid pressure, and moreover, strain stress generated in the valve body can be efficiently dispersed. Stress concentration near the center of the valve body can be avoided while Furthermore, the flat arc portion has a smooth shape and does not have an angular portion that easily generates turbulent flow, so that physical resistance on the fluid can be reduced and the flow of fluid in the body can be smooth, Since the flow passage area along the flow passage can be configured to have a gradual and continuous change, the occurrence of cavitation due to a rapid change in flow passage area can be suppressed. And since it is a simple and smooth shape, it is excellent in castability.

Furthermore, since the thickness of the horizontal rib adapted to the pressure distribution acting on the valve body surface can be formed efficiently by the pressure receiving, the weight increase of the valve body is avoided while securing the thickness of the horizontal rib necessary for the pressure resistance it can. Therefore, the wall thickness can be formed so that the required strength can be secured while efficiently avoiding the weight increase of the valve body. And since it is a simple and smooth shape, it is excellent in castability.

According to the second aspect of the invention, the elliptical shape is a shape that can be easily formed, and among the simple shapes, it is one of the most balanced shapes from the viewpoint of securing strength and reducing weight. . In addition, the elliptical portion can particularly efficiently disperse the stress that tends to be concentrated in the vicinity of the intersection of the horizontal rib and the longitudinal rib. In addition, it has a smooth shape with no corners. For this reason, it is possible to very easily form a horizontal rib which is excellent in castability, and in which strength is secured in a well-balanced manner and lightening is realized.

According to the third aspect of the present invention, it is possible to form the thickness of the horizontal rib efficiently adapted to the stress distribution generated in the valve body by the pressure receiving pressure, by simply changing the two parameters constituting the elliptical shape appropriately. The wall thickness of the horizontal rib which can ensure the necessary strength while avoiding the increase in weight of the valve body can be formed very easily.

According to the invention of claim 4 , if the cross-sectional shape of the longitudinal rib perpendicular to the flow channel direction is a hollow cylindrical shape, when casting the valve body, the hollow longitudinal rib can be easily formed and the valve body The weight can be reduced, and the longitudinal rib can be formed into a solid cylindrical shape even when the valve body is small and difficult to be formed hollow. Since the surface of a cylinder or cylinder has an arc shape, it is possible to efficiently increase the bending deformation strength to the fluid pressure acting on the surface, and the smooth arc shape does not have an angular portion that easily generates turbulence. As a result, the physical resistance exerted on the fluid can be reduced, the flow of fluid in the body can be smoothed, and the occurrence of cavitation can be suppressed, and the concentration of stress generated in the valve body can also be dispersed. Moreover, since it is a smooth shape, castability can also be improved.

According to the invention of claim 5 , since the connecting portion of the vertical rib and the horizontal rib and the connecting portion of the valve plate portion of the disc and the horizontal rib are smoothly connected in a rounded shape or an arc shape, the protrusion of the horizontal rib or the like From the surface of the valve body on which the formation portion is formed, it is possible to remove the corner portion or step portion which is likely to generate turbulent flow. Therefore, the flow of fluid in the vicinity of the surface of the valve body can be smoothed to suppress the occurrence of cavitation, and the concentration of stress generated in the valve body can also be dispersed. Moreover, since the shape is smooth, the castability can be enhanced.

According to the sixth aspect of the present invention, the thick ring portion enhances the rigidity of the disc outer peripheral end, so that it is possible to increase the bending deformation strength to the fluid pressure. Further, since the outer peripheral end face of the valve body in sliding contact with the seal member can be kept thin, an increase in the contact area between the seal member and the outer peripheral end face of the valve body can be avoided. Therefore, it is possible to improve the strength of the valve body while avoiding an increase in the rotational torque.

According to the seventh aspect of the present invention, it is possible to remove the corner portion or step portion which easily generates turbulent flow from between the thick ring portion and the outer end portion of the horizontal rib. Therefore, the flow of fluid near the surface of the valve body can be smoothed, and the occurrence of cavitation can be suppressed, and furthermore, the concentration of stress generated in the valve body can be dispersed. Moreover, since it is a smooth shape, castability can also be improved.

According to the eighth aspect of the present invention, since the cross-sectional shape of the thick ring portion is formed into a circular or elliptical shape, it is possible to efficiently increase the bending deformation strength to the fluid pressure acting on the surface. In addition, since the smooth circular or elliptical shape does not have angular portions that easily generate turbulent flow, the physical resistance exerted on the fluid can be reduced and the flow of fluid in the body can be smoothed, and cavitation can be generated. It is possible to suppress and to disperse the concentration of stress generated in the valve body. Moreover, since it is a smooth shape, castability can also be improved.

According to the invention as set forth in claim 9 , the required strength over the entire area of the valve body and the sealing property of the valve when the valve is closed is secured, and the weight of the valve body and the operation torque for opening and closing the valve are reduced. A central butterfly valve having a butterfly valve having a surface shape capable of suppressing stress concentration on the valve body and occurrence of turbulent flow and cavitation and having excellent castability can be realized.

It is a front view of the valve body of the butterfly valve concerning the present invention. It is a perspective view of the valve body of the butterfly valve concerning the present invention. It is AA sectional drawing in FIG. (A) shows an I--I cross-sectional view in FIG. 1, and (B) shows a-Ro-R cross-sectional view in FIG. It is a BB sectional view in FIG. It is CC sectional drawing in FIG. It is a perspective view of a butterfly valve concerning the present invention. It is DD sectional drawing in FIG.

  Hereinafter, preferred embodiments of a valve element of a butterfly valve in the present invention will be described in detail based on the drawings. 1 and 2 show a front view and a perspective view, respectively, of a valve body of a butterfly valve according to the present invention.

  As illustrated, the valve body of the butterfly valve in the present invention is a disc 1 formed in a disk shape, and the upper boss portion 2a and the lower boss portion 2b are vertically provided in a row from above and below A longitudinal rib 4 is formed in a substantially vertical direction with respect to the direction of the flow passage (not shown). The upper stem 18a (shown in FIG. 8) can be fitted and fixed to the stem insertion hole 3a of the boss 2a, and the lower stem 18b (shown in FIG. 8) can be fitted and fixed to the stem insertion hole 3b provided in the boss 2b. It has become.

  The horizontal rib 5 is formed to extend in the horizontal direction perpendicular to the vertical direction so as to vertically intersect the longitudinal rib 4 and the central portion of the disk 1. In the vicinity of the outer peripheral end 6 of the disk 1, a thick ring portion 7 which is concentric with the circular outer peripheral end 6 and exhibits a ring shape slightly shorter than the diameter thereof is formed. The horizontal rib 5 is connected to the thick ring portion 7. The sheet portion 8 which is the outer peripheral end face of the disk 1 is a portion which is in sliding contact with the sheet (rubber ring 16 in FIG. 8) when the disk 1 opens and closes the flow path. Further, a region other than the longitudinal rib 4 and the horizontal rib 5 on the disc inner side of the thick ring portion 7 is a valve plate portion 9 formed substantially flat.

  3 shows a cross sectional view taken along line A-A in FIG. 1, FIG. 4 shows a cross sectional view taken along a line I in FIG. 1 and FIG. 4B shows a cross sectional view taken in line in FIG. In FIG. 5, a cross-sectional view taken along the line B-B in FIG. 1 is shown.

  As illustrated in FIG. 3, the outer peripheral end 6 is smoothed by R-chamfering or C-chamfering and is not at least a corner. The thick ring portion 7 is formed on the slightly inner side of the disc 1 from the outer peripheral end 6, and the inner side of the thick ring portion 7 is substantially flat with a thickness t over the entire area thereof. The valve plate 9 is formed in As illustrated, the thickness between the outer peripheral end 6 and the thick ring portion 7 is also formed to the same thickness as the thickness of the valve plate portion 9. For this reason, the thickness of the sheet portion 8 in sliding contact with the sheet member is also formed to be substantially the same as the thickness t of the valve plate portion 9.

  In addition, as shown in FIGS. 1 and 2, the upper and lower portions of the thick ring portion 7 are integrally joined to the boss portion 2a and the boss portion 2b, respectively, and the junction has a corner portion and a step portion. It has a smooth shape.

  The cross-sectional shape of the thick ring portion 7 may be a smooth shape without corner portions such as a flat arc shape, a circle, or an ellipse, and is formed in a circle in this example. Further, the thick ring portion 7 and the valve plate portion 9 on the inner side of the disc 1 and the outer side thereof are joined in a smooth shape, and the shape is not particularly limited, but this example Then they are joined at the radius surface.

  The thick ring portion 7 thus formed on the outer periphery of the disk 1 acts on the outer periphery of the disk 1 when the pressure of the valve wing portion 11 which is the outer peripheral portion of the valve plate 9 is received. Since the rigidity to bending deformation is enhanced, the necessary strength of the disc 1 can be secured while maintaining the valve plate portion 9 thin. Also, since the entire thick ring portion 7 is formed inward of the disc 1 with respect to the outer peripheral end 6, it has a ring shape slightly shorter than the diameter of the disc 1, so the thickness of the sheet portion 8 is also It is kept thin. Therefore, even if the strength of the outer periphery of the disc 1 is secured by the formation of the thick ring portion 7, the area in which the disc 1 contacts the sheet member does not increase, and therefore the rotational torque of the disc 1 does not increase. .

  In the present embodiment, the thickness t is set to about 2.5 mm, and the circular diameter of the thick ring portion 7 is set to about twice the thickness t. Further, the diameter of the ring shape formed on the surface of the disc by the thick ring portion 7 is preferably set to 85% to 95% with respect to the outer diameter φd of the disc, and more preferably about 90%. is there.

  The flat arc portion 10 shown in FIGS. 3 and 4 is a cross-sectional portion obtained by cutting the horizontal rib 5 in the longitudinal rib direction. The cross-sectional shape of the flat arc portion 10 is an arc having a vertically long flat outer diameter, but it is a smooth shape having a predetermined thickness such that the horizontal rib 5 is raised. The shape is not particularly limited, and may be, for example, a single arc shape or an oval shape, or may be a gentle curve or the like having substantially the same curvature throughout the entire curve and a shape similar to the arc. In the present example, the cross-sectional shape of the flat arc portion 10 is an elliptical portion 10A. In the figure, the ellipse forming the elliptical portion 10A has the long side of length 2p in the vertical direction and the short side of length 2q in the horizontal direction. For this reason, the cross-sectional shape of the flat arc portion 10 of this example is an ellipse having a necessary shape by arbitrarily selecting the combination of the long side 2p and the short side 2q according to the nominal diameter of the valve, fluid pressure and the like. It can be formed appropriately.

  (A) and (B) of FIG. 4 are enlarged cross-sectional views in which the horizontal rib 5 is cut in parallel to the longitudinal rib 4 direction in FIG. 1, and (A) is a cross-sectional view along the line I--I of FIG. (B) shows a cross-sectional view in a roro line which is parallel to the ai line but is closer to the center of the disc 1 than the ai line. As shown in these (a) and (b), the cross section of the horizontal rib 5 cut in the longitudinal rib direction is formed so as to increase sequentially from the outer end 25 toward the center of the disc 1. .

  As described above, when the shape of the flat arc portion 10 is sequentially changed, the aspect of the change of the flat arc shape is a change aspect of sequentially increasing from the outer peripheral side of the disc 1 toward the longitudinal rib 4 side. It is not particularly limited. By changing in this manner, the horizontal rib 5 makes the flow of fluid smoother in the valve open state. As shown in FIG. 3, in this example, the elliptical portion 10A formed in an elliptical shape is formed in an elliptical shape that is a long side 2p and a short side 2q, but for example, the long side 2p and the short side 2q While one of the lengths is fixed, the other length may be increased at a constant or changing rate of change, and the long side 2p and the short side 2q may be appropriately correlated at a constant or changing rate of change. Alternatively, the size may be increased independently, and further, the area, the circumferential length, and the like of the elliptical portion 10A may be increased.

  The pressure distribution received by the valve body of the butterfly valve when fully closed is not uniform, and generally the load is greatest near the center of the valve body. Therefore, the flat arc shape of the flat arc portion 10 (elliptical portion 10A defined by the long side 2p and the short side 2q in FIG. 3) is moved from the longitudinal rib 4 side to the outer end 25 (outer side of the disk 1). If it is formed so as to increase gradually, the thickness near the center of the disc 1 where the load due to pressure is large is formed thick, while the thickness gradually formed outward of the disc 1, so Forming the thickness of the horizontal rib 5 corresponding to the unevenly distributed pressure load with predetermined accuracy, avoiding unnecessary weight increase of the disc 1, and simultaneously achieving the necessary strength and weight reduction of the disc 1 Can.

  Further, as shown in FIGS. 3 and 4, at least a square-shaped portion or a step portion is formed over the entire area of the connection portion 13 between the flat arc portion 10 (elliptical portion 10A) and the valve plate portion 9. The connecting portions 13 are joined in a smooth manner so that there is no particular restriction. However, in the present embodiment, the connecting portion 13 is formed in an arc shape or an arc shape, although the sectional shape is not particularly limited.

  5 shows a cross-sectional view taken along the line B-B in FIG. 1 and shows a cross-section of the longitudinal rib 4 which is the central portion of the disc 1 at the central portion, a cross-section of the horizontal rib 5 at the left and right, The cross section of the part 7 is shown integrally. The longitudinal rib 4 is formed in a hollow cylinder, and in this example is formed to be the thickest in the figure, but according to the nominal diameter of the disc 1 etc., the thickness of the longitudinal rib 4 and the horizontal rib 5 is about the same It may be formed in the thickness of Further, as described above, since the flat arc portion 10 (elliptical portion 10A) is formed so as to sequentially increase from the outer peripheral side of the disc 1 toward the longitudinal rib 4 side, the longitudinal length of the horizontal rib 5 in FIG. The thickness in the direction also increases in order from the outer peripheral side of the disc 1 to the longitudinal rib 4 side. In particular, the thickness of the horizontal rib 5 may be formed such that this change in height draws a gently inclined parabola with the central portion of the disc 1 which is the longitudinal rib 4 at the top in the figure as the top. If the horizontal rib 5 is formed to be a parabola, the thickness is not wasted, it is lightweight, the fluid resistance is not increased, and the reinforcing effect against stress can be spread over the entire disc 1.

  Further, in FIG. 5, a connecting portion 12 of the horizontal rib 5 and the vertical rib 4 is shown, and this connecting portion 12 is also similar to the connecting portion 13 between the flat arc portion 10 (elliptical portion 10A) and the valve plate portion 9. It is smoothly joined so that it does not form at least a square shape part or a step part over the whole region, and if it is joined in this way, the cross-sectional shape of the connection part 12 is not particularly limited, In the example, it is formed in a rounded shape or a circular arc shape.

  Furthermore, a cross section of the thick ring portion 7 is shown in the vicinity of the left and right end portions in FIG. 5, and in this example, the outer end portion 25 of the horizontal rib 5 shown in FIG. It is joined in the shape of a circle. Therefore, the thickness in FIG. 5 of the thick ring portion 7 is substantially the same as the thickness of the horizontal rib 5.

  As described above with reference to FIGS. 1 to 5, the horizontal rib 5 is connected to the longitudinal rib 4, the connecting portion 13 to the valve plate 9, and the outer end 25 to be joined to the thick ring portion 7. Is connected in a smooth shape, and the thick ring portion 7 and its disc 1 inner side and outer side are also connected in a smooth shape. Furthermore, in the present embodiment, also between the longitudinal rib 4 and the valve plate portion 9, and between the boss portions 2a and 2b and the valve plate portion 9 or the thick ring portion 7, the cross-sectional shape of their joint portion is smooth It is connected to become. For this reason, almost no corner or step is formed on the surface of the disk 1 shown in the present example, and the surface is formed with a smooth curved surface almost everywhere. As described above, when the corners and steps are not formed on the surface of the valve body, it is possible to effectively disperse the stress concentration due to the pressure received by the fluid, so it is possible to suppress local damage to the disc 1. .

  Also, when the valve element of the butterfly valve is fully open or in the middle open degree, the disc 1 is in the flow path and thus the flow path area of the fluid is reduced, but most corners and steps are formed on the surface Since this is not performed, the generation of turbulent flow and bubbles is suppressed, the rectification effect is high, and the generation of cavitation can also be effectively suppressed.

  6 is a cross-sectional view taken along the line C-C in FIG. As described above, since the disk 1 of the present invention has almost no corners or steps formed on the surface, it is rich in cast flowability and extremely excellent in castability. When casting the disc 1, as shown in FIG. 7 and FIG. 8 described later, the longitudinal rib 4 forming the rotation axis is formed into a cylinder, and the inside is formed into a hollow to reduce the weight of the disc 1. When the nominal diameter of the valve is small and it is difficult to form it into a hollow, the longitudinal rib 4 may be formed into a cylinder and the inside may be formed into a solid.

  In the present embodiment, the longitudinal rib 4 is formed into a hollow cylindrical section (outside diameter: 17 mm), and a cylindrical hollow portion is formed therein, and the hollow portion is formed from the large diameter portion 32 and the small diameter portion 31 having different diameters. It is formed. The diameter of the large diameter portion 32 is 11 mm, and the diameter of the small diameter portion 31 is 9 mm. Further, the upper stem insertion hole 3a is formed with a two-faced portion 34 fitted and fixed to the upper stem 18a, and the rotational force of the upper stem 18a is transmitted to the disk 1 by the abutment of the two-faced portion 34 with the upper stem 18a. Since the rotation of the upper stem 18a and the rotation of the disk 1 interlock with each other, the upper stem 18a rotationally slides on the shaft mounting portion. On the other hand, no two surface portions are formed in the lower stem insertion hole 3b, so that the lower stem 18b does not interlock with the rotation of the disc 1, and the lower stem 18b is non-rotatably fixed to its shaft mounting portion.

  The large diameter portion 32 and the small diameter portion 31 have a boundary near the position 35 connected to the horizontal rib 5. The height h of the position 35 from the lowermost end of the disc 1 is, in the same figure, the height from the lowermost end of the disc 1 to the vicinity of the intersection below the connecting portion 12 and the connecting portion 13 in FIG. It is. As described above, the diameter of the hollow portion formed inside the longitudinal rib 4 is slightly reduced from the lower side of the disc 1 to the vicinity of the position 35, and the longitudinal rib 4 is formed slightly thicker accordingly, In this case, the casting flowability from the longitudinal rib 4 to the horizontal rib 5 is improved, and casting defects can be prevented.

  Further, the thick ring portion 7 not only contributes to the improvement of the strength at the time of use as a valve body, but also exerts the strength at the time of manufacturing the disc 1 as described below. In this example, upper and lower stem insertion holes are machined into the cast disc 1 and the lower stem insertion hole 3b is formed by drilling, but the upper stem insertion hole 3a is formed after such drilling, A predetermined pressing blade is inserted vertically into the drilled hole to cut the two-faced portion 34. Then, when cutting the two-surface portion 34, the fixation of the disc 1 is maintained with high accuracy, and the axial centers of the upper and lower stem insertion holes 3a and 3b forming the rotation axis and the two-surface portion to be cut are made with high accuracy. It is necessary to make it correspond. As a method of fixing the disc 1, if the method of chucking the upper side (upper side) of the disc 1 is adopted, displacement easily occurs in the chuck, and the lower side (bottom side) of the disc 1 becomes free and the two-face portion to cut There is a possibility that the core 34 and the axis of the lower stem insertion hole 3b may be misaligned. In order to avoid this, as a method of fixing the disc 1, there is a case where a method of fixing a predetermined press support jig (not shown) so as to sandwich the lower side of the disc 1 is adopted.

  When cutting with a press blade in such a fixed state, a large stress acts on the disk 1 due to the friction with the press blade, causing bending deformation, which may cause the disk 1 to be deformed.

  In this respect, since the thick ring portion 7 is formed on the outer periphery of the disc 1, high rigidity is exhibited against such bending deformation. For this reason, the thick ring 7 can increase the strength of the disc 1 and prevent deformation even when cutting with such a press blade.

  Subsequently, an operation of the disc 1 according to the present invention used as a valve body when the valve is fully closed will be described. In this example, since the cross-sectional shape of the horizontal rib 5 of the disk 1 cut in the direction of the longitudinal rib 4 is elliptical, as described below, it has high strength against fluid pressure.

  When the valve is fully closed, the valve wing portion 11 of the disc 1, which is a valve body, is substantially perpendicular to the flow path direction and the seat portion 8 and the seal member are in close contact to seal the fluid. Of the degrees, the disc 1 as a whole receives most fluid pressure. The upper and lower portions of the disc 1 are axially supported by the upper and lower stems 18a and 18b, so that mainly the fluid pressure distorts the valve wings 11 on both sides with the upper and lower sides of the disc 1 as the fulcrum. Apply bending deformation force.

  Since the fluid pressure acts in this way, when considering the strength of the horizontal rib 5 against the fluid pressure when the valve is fully closed, temporarily the horizontal rib 5 is considered as a cantilever supported in a direction substantially perpendicular to the flow path In this case, the horizontal rib 5 is substantially perpendicular to the flow direction, and fluid pressure acts in the flow direction, and the horizontal rib 5 bends in the pressure receiving direction. The amount of change in deflection depends on the cross-sectional coefficient inherent to the cross-sectional shape of the horizontal rib 5. Generally, the larger the coefficient of section, the smaller the amount of change in deflection. For this reason, if the cross-sectional shape in which the amount of change in deflection becomes smaller is selected, the rigidity in the pressure receiving direction is enhanced, and the strength is improved. The cross section coefficient can be calculated strictly in the case of a simple cross sectional shape, and in general, the cross sectional shape is quadrangular, trapezoidal, elliptical or arc when the height from the neutral surface is the same. The cross-sectional coefficients of the chevrons become smaller in this order of description. For this reason, from the viewpoint of simply obtaining the strength, it is advantageous if the cross-sectional shape is a quadrilateral shape or a trapezoidal shape.

  However, as described above, in the case of a square shape or a trapezoidal shape in which this cross-sectional shape is to form a corner or a step on the surface of the disk 1, stress concentration, turbulence and cavitation are easily generated. In order to suppress these occurrences, it is necessary to adopt a cross-sectional shape that is a smooth shape. Accordingly, it is ideal to adopt a shape having the largest cross-sectional coefficient and the highest strength among the smooth shapes having no corner or step as the cross-sectional shape of the horizontal rib 5.

  In this respect, if the flat circular arc portion 10 is an elliptical portion 10A exhibiting a smooth oval, since the section coefficient is one of the largest shapes among the smooth cross sectional shapes, it is necessary to reduce the amount of deflection change with respect to the receiving pressure. It is possible to form a horizontal rib that can secure sufficient strength. Further, as described above, since the smooth shape does not have corner portions or the like causing a uniform shape change, it is possible to efficiently disperse the stress concentration on the horizontal rib 5 due to the distortion generated in the entire valve blade portion 11 at the time of pressure receiving. Since the surface of the disc 1 does not have corner portions that cause rapid changes in the flow path area, the occurrence of turbulent flow and cavitation is effectively suppressed. Furthermore, since the shape is smooth and simple, the flow of the molten metal at the time of casting is good and the castability of the disc 1 is also improved.

  In particular, when the heights of the horizontal ribs 5 (short sides 2q in FIG. 2) are the same, the section coefficient of the shape exhibited by the elliptical portion 10A is proportional to the length of the horizontal width (long sides 2p in FIG. 2). Therefore, the longer the long side 2p is set, the higher the strength of the horizontal rib 5 can be set, and the longer the long side 2p is set to flatten the shape of the ellipse, the more gently the unevenness of the surface shape of the disc 1 becomes. Since the change of the flow passage area is reduced, it is suitable for realizing a smooth fluid flow. However, if the long side 2p is too long, the weight of the horizontal rib 5 becomes excessive, so it is necessary to adjust it appropriately. As described above, in this example, the flat arc portion 10 is set to a horizontally long elliptical portion 10A whose long side 2p is appropriately long, and the long side 2p is a disc according to fluid pressure, rotational torque, etc. The length can be appropriately set in consideration of the strength and weight of 1. Thus, the elliptical portion 10A can be formed simply by changing the length of the long side or the short side, and in the smooth shape which can be formed simply, from the viewpoint of securing the strength and reducing the weight Therefore, the dispersion effect of the stress (especially, in the vicinity of the connecting portion 12) which tends to be concentrated when the pressure is received by the valve wing portion 11 is particularly high.

  Next, an example in which the disc 1 according to the present invention is attached to a central butterfly valve will be described. FIG. 7 shows a perspective view of a state in which the disc 1 which is a valve element according to the present invention is mounted on a central butterfly valve 14 and the valve is fully closed. The central butterfly valve of this example is a manual type, 15 is a cylindrical body with a flow passage inside, and 16 is a rubber ring which is a sheet member. 1 is mounted as a valve body and pivotally supported by the upper stem 18a and the lower stem 18b. The disc 1 is inclined about the upper stem 18a and the lower stem 18b as a valve body, and when fully closed, the rubber ring 16 and the seat portion 8 are in close contact to close the flow path.

  The handle 17 for manual operation is fixed so that the upper stem 18a can be rotated. When the lever 19 fixed to the handle 17 is not gripped, the root portion of the lever 19 is integrally formed with the resin yoke 20. When adjusting the opening degree of the valve body, the lever 19 is gripped with the handle 17 to rotate the handle 17 while releasing the engagement, and the necessary opening is performed. When it comes to the degree position, the lever 19 is released and the root portion is engaged with the gear 21 to maintain the opening degree. The yoke 20 is fixed to the body 15 by two hexagonal socket bolts 22.

  FIG. 8 is a cross-sectional view taken along the line D-D in FIG. The DD cross section is a cross section formed by both the flow path direction of the valve and the upper and lower stem rotation axis directions. As shown, the upper stem 18a is fitted into and fixed to the upper stem insertion hole 3a of the disc 1 and the lower stem 18b is fixed to the lower stem insertion hole 3b of the stem insertion hole 3b. The upper stem 18 a is axially mounted on the body 15 via the bearing 25 and the O-ring 26, and the upper end thereof is connected to the handle 17 via the yoke 20. Further, although not shown, a two-faced portion 34 is formed in the stem insertion hole 3a also in this example, and the two-faced portion 34 abuts on the upper stem 18a to transmit the rotational force of the handle 17 to the disc 1. The lower stem 18b is axially mounted on the bottom of the body 15 via a bearing 27 and an O-ring 28, and the lower end is supported by a bottom plate 29. The bottom plate 29 is formed in a cruciform shape and has an end It is fixed by a stopper 30 which is attached by being engaged with engaging portions 37 provided at four places at the lower end portion of the body 15. The outer periphery of the rubber ring 16 is fitted into and fixed to the uneven surface formed on the inner periphery of the body 15, and is in sliding contact with the sheet portion 8 of the disc 1 to seal the fluid.

  Further, a holding ring 36 is attached to each of the upper stem 18a and the lower stem 18b on the contact surface of the body 15 of the rubber ring 16 to prevent twisting of the rubber ring 16 caused by rotation of these stems and sliding of the disc 1 The stability at the time of valve body rotation is improved.

  The above-mentioned structure is an example, and is not limited to this. Further, the disc 1 according to the present invention can be widely used not only as a manual butterfly valve as in this example but also as a valve body of a central butterfly valve, for example as a valve body of an automatic butterfly valve equipped with an actuator. It can be used.

  Furthermore, the present invention is not limited to the description of the above embodiment, and various modifications can be made without departing from the spirit of the invention described in the claims of the present invention.

1 Disc (valve body)
2a Upper boss portion 2b Lower boss portion 3a Upper stem insertion hole 3b Lower stem insertion hole 4 Vertical rib 5 Horizontal rib 6 Outer peripheral end 7 Thick ring portion 9 Valve plate portion 10 Flat arc portion 10A Elliptical portion 11 Valve wing Part 12, 13 Connection part 14 Central type butterfly valve 15 Body 16 Rubber ring 17 Handle 18a Upper stem 18b Lower stem 25 Outer end

Claims (9)

A valve body of a butterfly valve provided rotatably in the cylindrical body via upper and lower stems, and bosses provided on the upper and lower sides of the disc-like disc are connected by vertical ribs, and the front and back surfaces of the disc are A horizontal rib is formed in a horizontal direction intersecting the vertical rib, and a flat surface of the horizontal rib is a flat surface perpendicular to the disc and is a cross-sectional shape cut in the direction of the vertical rib and an arc having an outer diameter of a vertically long flat shape. A valve body of a butterfly valve, wherein the flat arc portion is formed into a circular arc portion, and the flat outer diameter is sequentially increased from the outer peripheral side of the disc toward the longitudinal rib side. The valve body of a butterfly valve according to claim 1 , wherein the flat arc portion is an elliptical portion, and the elliptical portion has a cross-sectional shape cut in the longitudinal rib direction as a longitudinally elongated elliptical portion. The valve body of a butterfly valve according to claim 2 , wherein the elliptical portion is formed such that the short side and the long side of the elliptical shape sequentially increase from the outer peripheral side of the disc toward the longitudinal rib side. The valve body of a butterfly valve according to any one of claims 1 to 3 , wherein the longitudinal rib is a cylindrical or cylindrical cross section. The connecting portion between the longitudinal rib and the horizontal rib, the connecting portion between the valve plate portion of the disc and the horizontal rib is connected in a rounded shape or a circular arc shape in any one of claims 1 to 4. Valve body of the described butterfly valve. The valve body of a butterfly valve according to any one of claims 1 to 5 , wherein a ring-shaped thick ring portion is formed in the vicinity of the outer peripheral end of the front and back surfaces of the disc. The valve body of a butterfly valve according to claim 6 , wherein the thick ring portion and the outer end portion of the horizontal rib are joined in a flat shape. The valve body of a butterfly valve according to claim 6 or 7 , wherein a cross-sectional shape of the thick portion of the thick ring portion is circular or elliptical. Centric butterfly valve provided openably the valve body of the butterfly valve according to the inner periphery of the rubber ring mounted within said body through said upper and lower stem to any one of claims 1 to 8.

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