JP2012047205A - Valve body of butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve body of a butterfly valve capable of enhancing strength by dispersing stress when the valve is closed while enhancing torque performance when operating the valve by reducing the weight of the whole body.SOLUTION: In the valve body of the butterfly valve in which the vertical boss 2 of disc-shape valve body 1 is continuously arranged in a longitudinal direction, the tubular hexagonal cross-sectional part 3 is formed in the center the area T of the boss 2 and the tubular circular cross-sectional parts 4 are formed near the stem fitting parts 8 at the top and the bottom other than the hexagonal cross-sectional part 3 in the valve body 1 of the butterfly valve. The boss 2 and the valve wing parts 5 are connected by the connection R parts 7 and the connection R parts 7 are connected by gradually changing part R6 set gradually from the small connection R to the large connection R from both top and bottom of the circular cross-sectional part 4 to the center 3b of the hexagonal cross-sectional part 3.

Description

  The present invention relates to a valve body of a butterfly valve, and more particularly to a valve body having a relatively large diameter and requiring strength against fluid pressure when the valve is closed.

  Normally, the valve body of the butterfly valve is rotatably mounted in the body in a state in which the diameter direction is supported by a stem that is rotatably mounted in the body in which the elastic seat ring is fitted. With this mounting structure, when the flow path of the butterfly valve is closed, a larger fluid pressure is applied to the valve body than the flow path. Particularly, for example, with a relatively large aperture size of about 350 to 600 A, the nominal pressure Is about JIS 16K or 20K, ISO PN16 or PN20, ASME class 125 or class 150, the area of the valve body that receives the fluid pressure increases, and it is necessary to ensure the strength of the valve body against the fluid pressure.

In this case, there is one that ensures the strength of the valve body by attaching an integral stem to the valve body, but the material cost for the stem becomes expensive, and the entire valve is disassembled when the valve body is attached or detached. Therefore, it becomes necessary to remove the valve body and the stem, so that replacement of the valve body and assembly / maintenance of the valve are deteriorated.
In addition, it is conceivable to increase the thickness of the valve body to ensure the strength, but in this case, an increase in the weight of the entire valve body increases the operating torque, leading to a decrease in operability.

  Therefore, by providing a structure in which the upper and lower ends of the valve body are supported by divided stems, the material cost of the stem is reduced, and the ease of attaching and detaching the valve body is secured by inserting and removing the stem, and the strength against fluid pressure is increased. There is a need for a valve body that can improve torque performance while ensuring it. By using such a valve body for a valve having a larger caliber size, it is possible to reduce the weight of the valve body and improve operability while ensuring strength against a strong fluid pressure.

As a valve body of this type of split stem type butterfly valve, for example, a valve body of a central butterfly valve disclosed in Patent Document 1 is known. In the valve body of the butterfly valve of the same document 1, the boss portion for inserting the stem is formed independently on the top and bottom sides of the valve body, and reinforcing plates having substantially the same width as the both boss portions are integrally provided on both sides of the valve body. It has been. In this valve body, a boss portion is reinforced by providing a reinforcing plate, and this reinforcement is intended to prevent bending failure due to fluid.
As another structure of the valve body for improving the strength of the boss portion, a valve body disclosed in Patent Document 2 is known. The valve body is integrally formed so that a boss portion having a hexagonal cross section is connected to the top and bottom, and the valve body is reinforced by the boss portion. Between the boss portion and the wing portion of the valve body, a rounded portion having a small uniform radius is formed from the outer peripheral side to the central portion.

Furthermore, in the valve body of the butterfly valve disclosed in Patent Document 3, an integral boss connected to a top and bottom having a circular cross section is formed, and an inclining fillet portion is formed from the side surface of the boss portion toward the left and right wing portions of the valve body. Is formed. This valve body has a substantially conical wing portion, and is entirely reinforced by a top-and-bottom integrated boss having a circular cross section and a wing portion of the valve body provided with a fillet portion.
As another structure of the valve body that attempts to improve the overall strength by reinforcing the wing part as described above, in Patent Document 4, a plurality of lateral ribs extending in the X-axis direction are formed. It is trying to reduce the weight by improving the strength and reducing the thickness of the valve body.

Utility Model Registration No. 2523948 Japanese Patent No. 3026245 Utility Model Registration No. 2596327 Japanese Patent No. 3676795

However, when reinforcing the valve body by improving the strength of the boss portion, the valve body of the butterfly valve of Patent Document 1 has a structure in which a reinforcing plate, which is a separate member, is provided. As it worsened, the number of parts increased, and the number of man-hours at the time of production increased, which took time.
In the case of the valve body in the literature 2, the strength of the boss portion is increased by forming the valve body so as to be connected to the top and bottom. However, the radius of the radius portion connecting the boss portion and the wing portion of the valve body is small. Since the radius part of the same radius is connected from the outer peripheral part of the body to the center part of the blade, the stress is concentrated on the radius part with respect to the static load in which the maximum operating pressure is applied in the valve closed state. In addition, this valve body tries to improve the strength of the boss itself by adopting a boss with a hexagonal cross section, but the wing part, which is thinner than the boss part, is subjected to a bending moment due to fluid pressure. As a result, the stress is easily concentrated through the rounded portion which is the connecting portion between the boss portion and the wing portion, and the durability is deteriorated. As a countermeasure, it is conceivable to increase the thickness of the blade portion. However, if the thickness is increased, the weight of the entire valve body is increased and the torque performance is deteriorated.

  On the other hand, in the case of forming an inclined thickened portion from the boss portion on the wing portion as in the same document 3, the weight increases due to the height of the substantially conical wing portion, and the torque performance is poor. It was. In addition, the stress generated by the fluid pressure tends to decrease as the outer periphery of the wing part becomes smaller, so that the built-up area near the outer periphery of the wing part is wasted in terms of strength improvement, and the weight is also increased. It was increasing.

  When a rib is provided on the valve body as in the case of the same document 4, concentrated stress is generated at a portion where the rib is connected to the blade portion, and distortion occurs in a portion where the rib is not formed due to the concentrated stress. was there. When the valve body is distorted, the durability is adversely affected, for example, plastic deformation occurs and the sealing performance is lowered. In general, the valve body is often manufactured by casting. However, especially when a rib is formed by casting on a valve body with a medium diameter or larger, the thickness difference between the thick and thin parts of the valve body increases. Thus, casting defects are likely to occur, and the adverse effect due to the difference in thickness increases as the valve diameter increases. On the other hand, a valve body having ribs can be manufactured by welding means, but in this case, productivity is lowered and costs are increased, which is not general.

  The present invention has been developed to solve the above-mentioned problems, and the object of the present invention is to distribute the stress when the valve is closed while reducing the overall weight and improving the torque performance during valve operation. An object of the present invention is to provide a valve body of a butterfly valve that can be improved in strength.

  In order to achieve the above object, the invention according to claim 1 is a valve body of a butterfly valve in which the top and bottom boss portions of a disc-like valve body are provided in a vertical direction, and has a cylindrical shape in the central region of the boss portion. A hexagonal cross section is formed, and a cylindrical circular cross section is formed in the vicinity of the stem fitting part other than the hexagonal cross section, and the boss part and the valve blade part of the valve body are connected and connected by the R part. The joint R portion is a butterfly valve body connected by gradually changing R, which is gradually increased from a small joint R toward the central portion of the hexagonal section from both the top and bottom of the circular section.

  The invention according to claim 2 is the valve element of the butterfly valve in which the hexagonal section has a hexagonal two-surface parallel direction arranged parallel to the valve blade outer diameter direction.

  In the invention according to claim 3, the gradual change R of the joint R portion is gradually formed from small R to large R from both the top and bottom of the valve body, and the flange portion is formed by overlapping of the joint R portions at the central portion of the valve body. It is a valve body of a butterfly valve.

  The invention according to claim 4 is the butterfly valve body in which the overhang amount of the flange portion protruding in the valve blade outer diameter direction is set to about 40 to 45% of the valve body radius.

  The invention according to claim 5 is a valve body of a butterfly valve in which the valve blade portion has a conical shape, and the surface of the valve body is inclined toward both sides from the center of the valve body to distribute the stress applied to the valve body.

  The invention which concerns on Claim 6 is a valve body of the butterfly valve which each fitted the upper and lower stems to the stem fitting part of the top and bottom of the boss | hub part.

  According to the first aspect of the present invention, the hexagonal cross section is provided in the central region of the boss portion, the circular cross section is provided in the vicinity of the stem fitting portion of the top and bottom, and the boss portion and the valve blade portion of the valve body have a gradual change R. By connecting with the connection R, it can be easily manufactured by casting without increasing the number of parts, and this shape improves the torque performance during valve operation by maintaining the overall thickness and reducing the weight. Furthermore, the stem fitting portion where the generated stress is slight is made a circular cross section, thereby further reducing the weight. In this case, by preventing stress concentration due to fluid pressure when the valve is closed and dispersing the stress, the strength can be improved and the sealing performance when the valve is closed can be secured. Even when this valve body is used for a large-diameter valve, it is possible to improve the operability by reducing the operating torque while ensuring the strength of the valve body. This makes it possible to reduce the overall size by mounting a small actuator. In addition, when the valve is opened, the uneven portion near the boss portion is reduced, so that the occurrence of turbulent flow in the vicinity of this portion and the secondary side can be reduced, and the pressure loss can be reduced to improve the flow characteristics. .

  According to the invention according to claim 2, by arranging the hexagonal two-surface parallel direction of the hexagonal section in parallel with the valve blade outer diameter direction, the fluid resistance at the time of valve opening can be minimized, In addition, the parallel portion makes it easier to place the valve body sideways, so that the seating is improved during machining and the like, and the holding by a jig or the like is facilitated, and the machining is simplified.

  According to the invention of claim 3, the thickness of the valve blade portion can be kept thin, and the stress generated in the valve body with respect to the static load when the maximum operating pressure is applied in the valve closed state is It is possible to manufacture a lightweight valve body that maintains the strength of the valve body by dispersing it over a wide area. Moreover, since the uneven portion of the valve body can be reduced by the gradual change R, the liquid pool in the valve body is reduced even when a highly viscous fluid is flowed. By optimizing the joint shape of the joint R section that connects the boss section and the valve blade section, for example, while maintaining a substantially equivalent strength compared to a valve body having a boss section with a cylindrical shape connected to the top and bottom. It is also possible to greatly reduce the weight.

  According to the invention which concerns on Claim 4, the balance of a valve body weight and stress dispersion | distribution can be set to an optimal state, both the improvement of operativity by light torque and the improvement of the sealing performance of a valve by the strength improvement of a valve body are carried out. A valve body can be formed while ensuring functionality.

  According to the fifth aspect of the present invention, it is possible to reinforce the whole and disperse the stress applied to the valve body to improve the strength, and particularly to reduce the overall weight by stealing a lot of meat near the insertion site of the stem. Can be achieved.

  According to the invention according to claim 6, by providing the structure in which the valve body is fixed to the valve body using the separated upper and lower stems, the material used for the stem can be reduced compared to the structure using the integral stem, The valve body can be easily replaced.

It is a schematic perspective view which shows embodiment of the valve body of the butterfly valve in this invention. It is a front view of FIG. FIG. 3 is a plan view of FIG. 2. It is a cross-sectional view in which a part of the valve body is omitted. (A) is a cross-sectional view in which a part of the valve body of the butterfly valve according to the present invention is omitted. (B) is a partially omitted cross-sectional view of a valve body in a comparative product. It is principal part explanatory drawing of a valve body. (A) is principal part explanatory drawing of the valve body of the butterfly valve in this invention. (B) is principal part explanatory drawing of the valve body in a comparative product. It is a perspective view which shows embodiment of the valve body of the butterfly valve in this invention. FIG. 3 is a cross-sectional view of FIG. 2. (A) is DD sectional view taken on the line. (B) is EE sectional view taken on the line. (C) is a FF line sectional view.

  Hereinafter, preferred embodiments of a valve body of a butterfly valve according to the present invention will be described in detail with reference to the drawings. 1 shows a perspective view of a valve body of a butterfly valve according to the present invention, FIG. 2 shows a plan view of FIG. 1, and FIG. 3 shows a plan view of FIG. In FIG. 6, the more detailed perspective view of the valve body of the butterfly valve of this invention is shown.

  As shown in the figure, a valve body 1 of a butterfly valve according to the present invention is formed in a disc shape and has a shape in which a boss portion 2 is continuously provided in a vertical direction from the top and bottom. A hexagonal section 3 and a circular section 4 are formed, and the boss section 2 and the valve blade section 5 of the valve body 1 are connected by a connecting R section 7 having a gradual change R6.

  In the butterfly valve body 1, the boss portion 2 is provided with a through hole 9 in the vertical direction, and a hexagonal section 3 is formed in the central region T of the boss portion 2. The parallel direction of the two surface portions 3a forming the hexagon in the hexagonal section 3 is arranged in parallel to the valve blade outer diameter direction, so that the parallel two surface portions 3a are illustrated when the valve is closed. The direction is perpendicular to the non-flow channel. The hexagonal section 3 is preferably a regular hexagonal shape, but may be a hexagonal shape other than the regular hexagonal shape. Further, the central region T of the valve body 1 has a shape other than the hexagonal sectional shape. For example, it is possible to form a polygonal section such as an octagonal section or a decagon section.

  The circular section 4 is formed in a cylindrical shape near the top stem fitting part 8 other than the hexagonal section 3, and is connected by the hexagonal section 3 and the smooth curved surface part 10. An annular seat surface 15 is formed at the edge of the stem fitting portion 8, and the end of the circular section 4 is formed in a substantially conical shape toward the annular seat surface 15. In the circular cross-section 4, the curved portion 10 does not form a linear outer shape from the hexagonal cross-section 3 to the circular cross-section 4, thereby reducing the channel resistance when the valve is opened.

  The valve blade portion 5 is provided in a substantially disk shape on both sides of the boss portion 2, and when the valve body 1 is rotated, the valve blade portion 5 can contact and separate from an elastic seat ring of a butterfly valve (not shown) to open and close the flow path. It has become. The valve blade portion 5 is formed in a conical shape, and the stress applied to the valve body 1 is dispersed by inclining the valve body surface portion 5a from the center of the valve body 1 toward both sides.

  In FIG. 7, the boss portion 2 and the valve blade portion 5 described above are connected by a connecting R portion 7. The joint R portion 7 has a gradual change R6, and this gradual change R6 is set from a small joint R to a gradually larger R from both the top and bottom of the circular section 4 to the central portion 3b of the hexagonal section 3. It has a different shape. That is, the R dimension of the gradual change R6a in FIG. 7 (a), the gradual change R6b in FIG. 7 (b), and the gradual change R6c in FIG. The gradual change R6 is set to a curved surface having a gradually increasing radius toward the center of the valve body 1. In this case, for example, when the radius dimension of the gradual change R6a is 16 mm, the shape of the gradual change R6 may be such that the radius dimension of the gradual change R6c is 90 mm. In the central portion 3b of the valve body 1, a flange portion 11 is formed by overlapping the connecting R portions 7 formed from the top and bottom directions.

  As shown in FIGS. 1 and 2, the overhang amount W when the flange portion 11 projects in the outer diameter direction of the valve blade portion 5 may be set to about 40 to 45% of the valve body radius L. Further, in the vicinity of the circular section 4 where the upper and lower stems 12 and 13 are fitted, it is desirable to minimize the height of the connecting R section 7 when weight reduction of the valve body 1 is emphasized.

  In FIG. 1, boundary lines are shown in the vicinity of the boundary between the boss part 2 and the valve blade part 5, the cross-sectional hexagonal part 3 and the cross-sectional circular part 4, but actually, as shown in FIG. The boss part 2 and the valve blade part 5 are connected, and the R part 7, the cross-sectional hexagonal part 3 and the circular cross-sectional part 4 are smoothly connected by the curved surface part 10.

  Although not shown, the valve body 1 can be used as a valve body of a butterfly valve having a general structure. For example, the valve body 1 is fixed to a valve body fitted with an elastic seat ring via the upper and lower stems 12 and 13 shown in FIG. The upper stem 12 protruding to the upper side is formed on the stem fitting portion 8 formed inside the upper end side (top side) of the boss portion 2, and the lower stem 13 is disposed on the lower end side (ground side) boss portion of the boss portion 2. It can be attached to the valve body so as to be rotatable by being fitted to stem fitting portions 8 formed on the inside of the valve body. Further, the upper stem 12 is provided with operating means comprising an automatic actuator or a manual handle, and the valve body of the butterfly valve can be controlled to rotate to a predetermined valve opening degree automatically or manually by this operating means. The attachment structure of the upper and lower stems 12 and 13 may be opposite to the structure described above.

Subsequently, the shape of the vicinity of the hexagonal section 3 in the cross section of the above-described butterfly valve body will be described in more detail.
FIG. 4 shows a partially omitted cross-sectional view of the valve body, in which the valve blade portion is omitted in order to compare the strength of the valve body against stress. 4 (a), a partially omitted cross sectional view of the hexagonal section 3 of the cross section of the valve body of the butterfly valve in the present invention, and in FIG. 4 (b), a valve body in a comparative product for comparison with the present invention. In the comparative valve body 20, a cylindrical portion 21 is formed in a portion corresponding to the hexagonal section 3 of the cross section of the valve body 1 of the butterfly valve of the present invention. Yes. And the outer diameter dimension B of the cylindrical part 21 of FIG.4 (b) is provided equally with respect to the opposite side dimension A of the cross-sectional hexagonal part 3 of Fig.4 (a).

4 (a) and 4 (b), the inside of the through-hole 9 that is the internal punched-out portion is set so that the cross-sectional area of the hexagonal section 3 shown by hatching is equal to the cross-sectional area of the cylindrical section 21. The circumferential circle 14 and the inner circumferential circle 23 of the through hole 22 are provided at different inner diameters, and the dimensions of the inner circumferential circle 14 and the inner circumferential circle 23 are an inner diameter φd ₁ and an inner diameter φd ₂ , respectively. 3 and the strength of the cylindrical portion 21 are compared.

When the cross-sectional areas of the hexagonal section 3 and the cylindrical section 21 are equal, the distance S ₁ from the center point O ₁ of the hexagonal section 3 to the farthest vertex (position) is the center point of the cylindrical section 21. It becomes longer than the distance (= radius length) S ₂ from the position farthest from O ₂ and the cross-sectional area of the cross section increases. From this, the section hexagonal portion 3 is larger than the cylindrical portion 21 with respect to the section modulus and the section moment of inertia, and at this time, the section hexagonal section 3 is about 10% larger. In the case of such the same cross-sectional area (= when the weights are equal), the larger the section modulus can increase the rigidity against the fluid pressure, so that the inner circumference circle 14 and the inner circumference circle 23 When the cross-sectional areas are the same, the rigidity of the hexagonal section 3 can be higher than that of the cylindrical section 21.

  Accordingly, when the hexagonal section 3 having the same section modulus as that of the cylindrical section 21 is to be provided in the central portion, the sectional area of the hexagonal section 3 can be made smaller. When the central portion 3b of the valve body 1 is configured by the shape of the hexagonal section 3 in cross section, the cylindrical portion 21 has the same degree of rigidity as compared with the case where the central portion is configured by the shape of the cylindrical portion 21. The weight can be reduced more than the case.

For example, the opposite side dimension A of the hexagonal section 3 in FIG. 4A is 74 mm, the diameter φd ₁ of the inner circumferential circle 14 is 56 mm, the outer diameter B of the cylindrical part 21 in FIG. When the diameter φd _{2 of the} circle 23 is 62 mm, the cross-sectional area of the hexagonal section 3 is about 1723 mm ² , the cross-sectional area of the cylindrical section 21 is about 1837 mm ² , and the cross-sectional area of the hexagonal section 3 is the cylindrical section Slightly smaller than 21 cross-sectional area. Comparing the section modulus in this case, the minimum section modulus with respect to the X axis (horizontal axis) (not shown) of the hexagonal section 3 is about 29137 mm ³ , and the minimum section coefficient with respect to the X axis of the cylindrical section 21 is about 26735 mm ³ . Even if it is small, the section modulus of the hexagonal section 3 is approximately 10% larger than that of the cylindrical section 21.

  Moreover, the hexagonal section 3 has a configuration in which the parallel direction of the hexagonal two-surface portions 3a is arranged in parallel with the valve blade outer diameter direction, so that the fluid resistance when the valve is opened can be minimized. This makes it possible to provide a butterfly valve having excellent flow characteristics when the valve is open.

Next, the connecting R portion 7 and the gradual change R6 of the valve body 1 are compared with the connection round portion 24 of the comparative valve body 20 shown in FIG.
In FIG. 5, the principal part explanatory drawing of the valve body is shown, FIG. 5 (a) shows the shape in the vicinity of the hexagonal section 3 in the valve body 1 of the valve body 1 of the present invention, and FIG. The cross-sectional shape of the vicinity of the cylindrical portion 21 in the valve body 20 in the comparative product is shown.

As shown in FIG. 5 (a), a tangential curved surface connecting the hexagonal extension surface of the hexagonal section 3 and the conical surface portion of the valve blade section 5 is a connection R section 7, and this connection R section 7. A gradual change R6 is formed. On the other hand, as shown in FIG. 5B, a tangential connection round portion 24 is formed at a portion connecting the cylindrical portion 21 and the conical surface portion of the valve blade portion 26.
At this time, if the height C of the valve blade portion 5 and the height C ′ of the valve blade portion 26 are the same, the build-up amount of the build-up portion α provided by the gradual change R6 (shown in FIG. 5 (a)). The cross-sectional area of the hatched portion) can be made larger than the amount of build-up of the build-up portion β provided by the connection round portion 24 (cross-sectional area of the hatched portion shown in FIG. 5B). This gradual change R6 the same radius dimension in the central cross section, the case of forming the connection rounded portion 24, the difference in shape between the hexagonal cross section 3 and the cylindrical portion 21, connecting the overhang amount W ₁ by gradual change R6 This is because the overhang amount W ₂ by the rounded portion 24 can be made larger. As a result, it is possible to form the gradually increasing R6 near the central portion of the valve body 1 in the connecting R portion 7 having a larger amount than the surroundings, thereby providing an advantageous shape for reinforcing the valve body 1.

For example, the height C of the valve blade portion 5 when the aperture size is 400A in FIG. 5A is 17.5 mm, the radius around the center of the gradually changing R6 is R90 mm, and the opposite side dimension A of the hexagonal section 3 is the When 74 mm, can be provided projecting amount _{W 1} of the outer diameter direction of the valve wing portion 5 of the ridges 11 of the gradual change R6 near hexagonal cross section 3 about 81.8Mm. Similarly, the height C ′ of the valve blade portion 26 in FIG. 5B is 17.5 mm, the radius diameter near the center when the connection radius portion 24 is gradually changed is R90 mm, and the diameter φd _{2 of the} cylindrical section 21 is Is 74 mm, the overhanging amount W ₂ of the connection radius portion 24 in the vicinity of the cross-section cylindrical portion 21 in the outer diameter direction of the valve blade portion 26 is about 68.7 mm. Thereby, the build-up amount of the build-up portion α in FIG. 5A becomes larger than the build-up amount of the build-up portion β in FIG. Strength is improved.

Moreover, bulging amount W ₁ in the case of gradual change R6 is radially outward of the valve wing portion 5 of FIG. 5 (a), and the front and back direction both become both larger of the valve body 1, also increases the overall strength of the valve body 1 . When the gradual change R6 is formed, if the width dimension of the hexagonal part is slightly widened, the rounded dimension of the gradual change R6 can be formed larger, and the above-described overhanging part projects in the outer diameter direction of the valve blade part 5. The strength will increase the more you make it.

  The maximum dimension of the gradual change R6 has a limit due to the relationship between the dimensions of the hexagonal section 3 and the valve blade part 5. However, as described above, the overhang amount W of the flange 11 of the gradual change R6 is as follows. It may be set to about 40 to 45% of the radius of 1. When setting the dimension of the gradual change R6, if the dimension of the flange part 11 is set large, the conical height of the valve blade part 5 can be reduced. However, the formation part of the gradual change R6 increases, and the weight increases. If the dimension of 11 is set small, the formation portion of the gradual change R6 can be reduced, but it is necessary to increase the cone height of the valve blade portion 5, which increases the weight. When setting the collar part 11 and the gradual change R6, it is good to set to the appropriate shape which becomes large R gradually from the small joint R in consideration of these things.

  On the other hand, in the vicinity of the circular section 4 and in the vicinity of the outer periphery of the valve blade section 5, the generated stress under static load is light, so that strength is not required as compared with the vicinity of the central section 3 b. The inner diameter of the joint portion 8 is determined by the stem diameters of the upper and lower stems 12 and 13. For this reason, this portion, which does not require strength compared to the central portion 3b, is provided in the cross-sectional circular portion 4 having the same dimensions as the cross-sectional hexagonal portion 3, thereby reducing the thickness while reducing the thickness while maintaining the strength. Can be achieved. Further, the same applies to the gradual change R6. Since the stress generated in the joint R portion 7 near the circular section 4 is reduced, the gradual change R6 near the circular section 4 is small in consideration of durability and sealability. By providing the connection R, the weight can be reduced. As a result, the gradual change R6 in the vicinity of the central portion 3b where the stress is large is formed to be large, and the shape is advantageous in terms of stress. It is possible to improve the strength by dispersing the stress when the valve is closed while reducing the weight.

  When importance is attached to the weight reduction and stress relaxation of the valve body, the dimensions of the connecting R portion 7 may be set so that the position at which the valve body 1 is divided in the vertical direction is the maximum dimension. The above-mentioned collar portion 11 is provided at a position where the valve body 1 is divided into two in the vertical direction, and this collar portion 11 has a shape that protrudes to the outermost diameter side because the connecting R portion 7 has the maximum dimension. Thus, the valve blade portion 5 is most effectively reinforced by the shape of the flange portion 11, and the stress generated in the valve blade portion 5 is greatly dispersed throughout.

  Here, the valve body of the butterfly valve according to the present invention is used as a test sample, and the dimension of the gradual change R between the end side and the center side when the test sample is, for example, the aperture size 400A is shown in Table 1. . In order to compare with the valve body of the present invention, the radius dimension of the constant connection round portion of the comparative valve body is also shown in Table 1.

  In the valve body of the specimen having a valve body size of 400A in Table 1, it is desirable that the ratio of the projecting amount on the central side of the gradual change R with respect to the radius of the valve body is, for example, about 42%.

Next, a stress distribution was analyzed by simulation when a fluid pressure was applied to the valve body described in Table 1 to generate a stress. In this case, loads applied to the valve body (loads applied by fluid pressure) were set to 1.6 MPa, 1.8 MPa, and 2.0 MPa, and Mises stress distribution and maximum principal stress (tensile) distribution in this case were analyzed.
As a result of the analysis of these stress distributions, the valve body 1 (test sample) of the butterfly valve in the present invention has a reduced stress distribution near the central portion 3b where the section modulus is increased by the hexagonal section 3 in section, Due to the overall shape in which the connecting R portion 7 was formed, stress was applied to the whole from the central portion 3b to the vicinity of the outer peripheral portion. Therefore, stress concentration due to fluid pressure is less likely to occur in the valve body 1, and it is possible to prevent plastic deformation so that the vicinity of the hexagonal section 3 in the cross section is warped by the fluid pressure. It can be secured. Further, in the vicinity of the circular section 4 and in the vicinity of the outer peripheral end portion that tightly seals with the seat ring of a butterfly valve (not shown), a load due to stress is hardly applied, so that the sealing performance is reliably maintained.

  On the other hand, when a fluid pressure is applied to a valve body (comparative product) having a cylindrical boss portion connected to the top and bottom, the shape near the central portion where the fluid pressure is concentrated is the cylindrical portion 21 having a cylindrical cross section, so that In addition, the connecting round portion 24 having a constant size and a small radius of the rounded portion is formed instead of the connecting R portion having the gradual change R, so that stress is particularly generated near the central portion. It becomes easier to concentrate. Moreover, since the valve body is supported by the upper and lower stems, the primary side to which the fluid pressure of the valve body is applied is supported by being pushed to the stem side, while the secondary side is supported by the stem. It is not. For this reason, the deflection near the central portion becomes larger, and the stress concentration near the central portion causes a warp around the primary side surface and facilitates plastic deformation. Thereby, for example, when this valve body is used for a valve having a caliber of about 350 to 600 A including a caliber size of 400 A, the pressure receiving area increases, and it becomes difficult to ensure the strength of the valving element. Maintenance becomes even more difficult.

  The embodiment of the present invention has been described in detail above, but the present invention is not limited to the above-described embodiment, and the scope does not depart from the spirit of the invention described in the claims of the present invention. Thus, various changes can be made. Accordingly, the shape and outer diameter of the hexagonal section, the outer diameter and length of the circular section, the rounded shape of the gradual change R in the joint R section, the sectional shape and thickness of the valve blade section, etc. are appropriately specified. It is possible to provide a desired valve body according to the caliber size or application of the butterfly valve.

DESCRIPTION OF SYMBOLS 1 Valve body 2 Boss part 3 Section hexagon part 3a 2 surface part 3b Center part 4 Section circular part 5 Valve blade part 5a Surface part 6 Gradual change R
7 Connecting R part 8 Stem fitting part 11 Ridge part 12 Upper stem 13 Lower stem T Center area L Valve body radius W Overhang amount

Claims (6)

  A valve body of a butterfly valve in which a vertical boss portion of a disc-shaped valve body is provided in a vertical direction, and a cylindrical cross-sectional hexagonal portion is formed in the central region of the boss portion, and this cross-sectional hexagonal portion is other than A cylindrical circular section is formed in the vicinity of the stem fitting portion of the top and bottom of the top and bottom, and the boss section and the valve blade section of the valve body are connected by a connecting R section. A valve body of a butterfly valve, characterized in that the valve body is connected by gradually changing R which is gradually increased from a small connecting R to a center of the hexagonal cross section from both sides.   The butterfly valve body according to claim 1, wherein the hexagonal section has a hexagonal two-surface parallel direction arranged parallel to the valve blade outer diameter direction.   The gradual change R of the joint R portion is formed gradually from a small R to a large R from both top and bottom of the valve body, and a flange is formed by overlapping the joint R portion at the center of the valve body. The butterfly valve body according to 2.   The valve body of a butterfly valve according to claim 3, wherein the overhang amount that the flange projects in the valve blade outer diameter direction is set to about 40 to 45% of the valve body radius.   The valve body of the butterfly valve according to any one of claims 1 to 4, wherein the valve blade portion has a conical shape, and the stress applied to the valve body is dispersed by inclining the valve body surface toward both sides from the center of the valve body. .   The valve body of a butterfly valve according to any one of claims 1 to 5, wherein upper and lower stems are respectively fitted to the top and bottom stem fitting portions of the boss portion.

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