JP5369136B2 - Valve seal structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal structure of a valve, hardly generating an abnormal sound even when closing the valve, by maintaining high sealability over a long period. <P>SOLUTION: A valve seat 24 and a valve element 31 are oppositely arranged on the axis L of a flow passage in a casing, the inner peripheral edge 24A of the valve seat 24 is formed as a convex surface of a cross-sectional circular arc shape, a seat surface 24B of the valve seat 24 is formed in a plane shape of expanding in the crossing direction with the axis L, the valve element 31 is provided with a seal member 32 capable of sealing a valve hole 25 inside of the valve seat 24, and the outer peripheral side of the seal member 32 is provided with a tapered inclined face part 32A of diametrically contracting toward the central side of the valve hole 25 and a plane part 32B opposed to the seat surface 24B of the valve seat 24 and expanding in the crossing direction with the axis L from the large diameter side outer periphery of the inclined face part 32A. The plane part 32B contacts with the seat surface 24B of the valve seat 24 after the inclined face part 32A contacts with the inner peripheral edge 24A of the valve seat 24 when the valve element 31 is moved to the valve seat 24 side. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to a valve seal structure that closes a flow path by bringing a valve body into contact with a valve seat.

  In a conventional valve, a valve body accommodated in a flow path of a casing is configured to close the flow path by contacting the valve seat, and the valve body has a seal that can be in close contact with the seat surface of the valve seat. A member is provided in an annular shape, and the outer peripheral surface of the seal member is formed in a taper shape whose diameter decreases toward the valve hole center side inside the valve seat. When the valve body is moved to the valve seat side, the taper is tapered. It is known that the outer peripheral surface of the seal member is in surface contact with the seat surface of the valve seat formed in a shape to maintain the sealing performance of the valve hole (see, for example, Patent Documents 1 and 2).

JP 2010-38336 A JP 2005-282636 A

  However, in the conventional seal structure, the narrow portion is formed in a relatively wide range between the outer peripheral surface of the seal member and the seat surface of the valve seat in a state where the valve body is close to the valve seat. Therefore, when the flow path between the valve body and the valve seat is narrowed, the flow velocity of the fluid flowing therethrough increases accordingly, the entire narrow width portion becomes negative pressure, and the valve body is excessively drawn to the valve seat side. It is. As a result, it becomes easy to cause abnormal vibration that causes abnormal noise when the valve body is closed.

  Therefore, as shown in FIG. 6, the inner peripheral edge 92 of the valve seat 91 is a convex surface having an arcuate cross section, and in the state where the valve body 93 is close to the valve seat 91, the inner peripheral edge 92 and the tapered surface 95 of the seal member 94 A configuration in which the narrow portion is formed in a relatively narrow range between the two is conceivable.

  However, in the case of such a configuration, the pressure between the inner peripheral edge 92 of the valve seat 91 and the taper surface 95 of the seal member 94 by the pressure pressing the valve element 93 from the primary flow path 96 to the valve seat 91 side after the valve is closed. Since a load is applied to the contact portion in a concentrated manner from an oblique direction, the contact portion may be deformed over time, and the sealing performance of the valve hole 97 may be reduced.

  Further, in this structure, the gap between the valve body 93 and the valve seat 91 is configured to be tapered in a taper direction from the primary flow path 96 to the valve hole 97, so that the gap is narrowed by the venturi effect. The flow velocity rapidly increases at the portion S9, and the pressure around the narrow portion S9 rapidly decreases as indicated by the isobaric line (dotted line) in FIG. As a result, there is a risk of causing cavitation causing abnormal noise around the narrow portion S9.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a valve seal structure that can maintain high hermeticity over a long period of time and is unlikely to generate abnormal noise even when the valve is closed. To do.

In the present invention, the valve seat and the valve body are provided facing each other on the axis of the flow path in the casing,
The inner peripheral edge of the valve seat is formed in a convex surface having an arc cross section, and the seat surface of the valve seat is formed in a planar shape extending in a direction intersecting the axis,
The valve body is provided with a seal member capable of sealing the valve hole on the inner side of the valve seat. On the outer peripheral side of the seal member, there is a tapered slope portion that decreases in diameter toward the center side of the valve hole, and a valve seat A flat surface portion facing the seating surface and extending in a direction intersecting the axis from the outer periphery on the large diameter side of the slope portion is provided,
When the valve body is moved to the valve seat side, the flat surface portion is configured to contact the seat surface of the valve seat after the slope portion contacts the inner peripheral edge of the valve seat.

  In this configuration, the slope portion of the seal member is first brought into point contact with the inner peripheral edge of the valve seat, and then the flat portion of the seal member is further brought into surface contact with the seat surface of the valve seat. The pressure applied to the body is dispersed from the vertical direction with respect to the surface contact portion, and a load is applied. Thereby, aged deformation of the seal member is suppressed.

  Further, in a state where the valve body is close to the valve seat, the valve body is sandwiched between the valve seat and the flat surface portion of the seal member between the valve body and the equal width from the outside of the valve body toward the center of the axis. Part, the inner peripheral edge of the valve seat and the inclined surface portion of the seal member, and a reduced width part from the equal width part to the valve hole is formed, so the flow rate in the gap between the valve body and the valve seat is It rises gradually as it moves from the equal width part to the reduced width part without suddenly rising at the reduced width part. Therefore, the pressure in the gap gradually decreases as it moves from the equal width portion to the reduced width portion. Thereby, generation | occurrence | production of the cavitation around the reduced width part which causes abnormal noise is also suppressed.

  Furthermore, after the inclined surface portion of the seal member is in point contact with the inner peripheral edge of the valve seat, the flat portion of the seal member is in surface contact with the seat surface of the valve seat, thereby increasing the degree of negative pressure in the gap. Since the valve hole is sealed before by the point contact between the seal member and the valve seat, the valve body is hardly pulled into the valve hole side. Thereby, the vibration of the valve body that causes abnormal noise is also suppressed.

  In the valve seal structure, the valve body is preferably biased toward the valve seat by the elastic force of the spring.

  In this case, since the sealing member is pressed against the valve seat by a constant pressing force, the aging deformation of the point contact portion and the surface contact portion is further suppressed.

  In the valve seal structure described above, it is preferable that a corner portion connecting the slope portion and the flat portion is formed as a concave surface having a cross-sectional arc shape larger in diameter than the inner peripheral edge.

  In this, the gap between the valve body and the valve seat is continuously reduced from the equal width portion toward the reduced width portion, and the pressure in the gap gradually decreases as it moves to the valve hole. Occurrence of cavitation around the reduced width portion is further suppressed. Further, the vibration of the valve body due to excessive pulling of the valve body to the valve hole side is further suppressed.

  As described above, according to the seal structure of the present invention, abnormal noise hardly occurs when the valve is closed, and high sealing performance can be maintained for a long time after the valve is closed.

It is a schematic sectional drawing of the three-way valve provided with the valve seal structure which concerns on embodiment of this invention. It is a schematic sectional drawing of the seal member periphery of the three-way valve provided with the valve seal structure which concerns on embodiment of this invention. It is a figure which shows the state which the seal member and the valve seat made point contact in the seal structure of the valve which concerns on embodiment of this invention. In the valve seal structure according to the embodiment of the present invention, it is a diagram showing a state in which the seal member and the valve seat are in surface contact. It is a figure which shows the pressure distribution of a seal member periphery in the seal structure of the valve which concerns on embodiment of this invention. It is sectional drawing of the seal member periphery which shows the seal structure of the valve | bulb used as the premise technique of this invention. It is a figure which shows the pressure distribution of a seal member periphery in the seal structure of the valve used as the premise technique of this invention.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, a three-way valve 1 having a valve seal structure according to an embodiment of the present invention has three ports 11 and 12 for connecting pipes to the outer periphery of a casing 10 constituting the outer shell. , 13.

  The first port 11 and the second port 12 to which the secondary side pipe is connected are juxtaposed on the surface opposite to the arrangement surface of the third port 13 to which the primary side pipe is connected. . Further, in the casing 10, a first flow path 21 extending from the first port 11 toward a center line (hereinafter referred to as “axis line”) L of the casing 10, and the axis L from the second port 12. A second flow path 22 extending toward the axis and a third flow path 23 extending from the third port 13 toward the axis L are formed.

  Circular valve seats 24 are respectively formed on the wall surfaces of the third flow path 23 on the first flow path 21 side and the second flow path 22 side. It is connected to the first flow path 21 and the second flow path 22 through the valve hole 25 inside the seat 24.

  Each said valve hole 25 is provided in the position which mutually opposes, and the shaft 30 is penetrated along the said axis line L from the one end side of the casing 10 in the center of these valve holes 25. As shown in FIG. One end of the shaft 30 protrudes toward one end of the casing 10, and a motor (not shown) is connected to the end of the shaft 30. On the other hand, two substantially frustoconical valve bodies 31 are attached to the other end of the shaft 30 and facing the valve hole 25 in the third flow path 23 with their bottom surfaces abutting each other. .

  Accordingly, when the shaft 30 is moved in the direction of the axis L by the driving force of the motor (not shown), the two valve bodies 31 are simultaneously moved along the axis L in the third flow path 23 and one valve seat 24 is moved. And a distance from the other valve seat 24. And by controlling the position of the valve body 31 in this way, the opening ratio between the two valve holes 25 is adjusted, and the ratio of the diversion to the first flow path 21 and the second flow path 22 is adjusted. The

  The outer peripheral surface 310 of the valve body 31 is formed in a tapered shape with a diameter decreasing toward the center of the valve hole 25 from the third flow path 23 side. A sealing member 32 made of an elastic material and capable of being in close contact with the valve seat 24 is provided in an annular manner.

  In FIG. 1, E-rings 33 that support the valve bodies 31 in a positioned state are fitted into grooves formed in the shaft 30 on the upper surface sides of both valve bodies 31. Further, a concave portion 34 is formed along the outer periphery of the shaft 30 on each bottom surface side of both valve bodies 31, and a coiled compression spring 35 is sandwiched between the concave portions 34 of these two valve bodies 31. It is disguised. That is, the two valve bodies 31 are disposed between the E-rings 33 in a state where they are urged in the directions away from each other by the elastic force of the compression spring 35. Further, a predetermined clearance C is provided between the bottom surfaces of the valve bodies 31.

  Therefore, when the shaft 30 is moved to one end side thereof, the seal member 32 of the valve body 31 comes into contact with the valve seat 24. When the valve body 31 is further pressed from the position toward the valve seat 24, the reaction force applied to the seal member 32 within the formation range of the clearance C is absorbed by the elasticity of the compression spring 35. On the other hand, the pressing force of the valve body 31 against the valve seat 24 is limited to a certain level.

  As shown in FIG. 2, the inner peripheral edge 24 </ b> A of the valve seat 24 is formed as a convex surface having an arc cross section. The seat surface 24 </ b> B of the valve seat 24 is formed in a flat shape extending in the circumferential direction of the valve hole 25.

  On the other hand, on the surface of the seal member 32 on the valve seat 24 side, a tapered slope portion 32 </ b> A having a diameter reduced toward the center side of the valve hole 25 is provided. The slope portion 32A is inclined 45 degrees with respect to the axis L serving as the central axis of the valve body 31, and the inner peripheral edge 24A of the valve seat 24 is opposed to the approximate center of the slope portion 32A.

  In addition, a flat surface portion 32B that is substantially parallel to the seat surface 24B of the valve seat 24, that is, spreads in the circumferential direction of the valve body 31, is formed on the outer periphery on the large diameter side of the inclined surface portion 32A. The seating surface 24B of the seat 24 is opposed.

  Therefore, if the valve body 31 moves to the valve seat 24 side, the distance between the slope portion 32A of the seal member 32 and the inner peripheral edge 24A of the valve seat 24, and the seating surface of the flat portion 32B of the seal member 32 and the valve seat 24. As shown in FIG. 3, the slope portion 32A of the seal member 32 makes point contact with the inner peripheral edge 24A of the valve seat 24 and seals the valve hole 25, as shown in FIG. In this point contact state, the flat portion 32B of the seal member 32 and the seat surface 24B of the valve seat 24 are not in contact with each other, and a gap with a predetermined width is secured. Then, when the valve body 31 is further pushed toward the valve seat 24 against the elastic force of the spring 35 from this state, the flat portion 32B of the seal member 32 becomes the seat surface 24B of the valve seat 24 as shown in FIG. The valve hole 25 is sealed over a wider area.

  As shown in FIG. 5, the slope portion 32 </ b> A of the seal member 32 is formed in a planar shape, and the corner portion 32 </ b> C from the slope portion 32 </ b> A to the plane portion 32 </ b> B has a larger diameter than the inner peripheral edge 24 </ b> A of the valve seat 24. It is formed in a concave surface having a circular arc cross section. Further, the outer peripheral edge 32D of the flat portion 32B is formed as a convex surface having an arcuate cross section having substantially the same diameter as the inner peripheral edge 24A of the valve seat 24.

  That is, in a state where the valve body 31 is close to the valve seat 24, the valve body 31 and the valve seat 24 are sandwiched between the flat portion 32B of the seal member 32 and the seat surface 24B of the valve seat 24. A width portion S1 and a reduced width portion S2 sandwiched between the slope portion 32A of the seal member 32 and the inner peripheral edge 24A of the valve seat 24 are formed. The equal width portion S1 extends from the third flow path 23 toward the center side of the valve body 31, and the reduced width portion S2 continuously and gradually extends from the equal width portion S1 toward the valve hole 25. The width is reduced.

  Accordingly, the flow velocity in the gap between the valve body 31 and the valve seat 24 does not rapidly increase at the reduced width portion S2, but gradually increases as it moves from the equal width portion S1 to the reduced width portion S2. According to the pressure analysis, as indicated by the isobaric line (dotted line) in FIG. 5, the pressure in the gap between the valve body 31 and the valve seat 24 gradually decreases as it moves to the valve hole 25. Thereby, it was confirmed that the pressure change in the gap between the valve body 31 and the valve seat 24 is gentler than that of the shape shown in FIG.

  Further, the inclined surface portion 32A of the seal member 32 is disposed inwardly one step from the outer peripheral surface 310 of the valve body 31, and a stepped portion S3 formed between the equal width portion S1 and the reduced width portion S2. The flow of the fluid from the equal width portion S1 to the reduced width portion S2 is stalled to suppress a rapid decrease in pressure around the reduced width portion S2.

  Thus, according to the above-described embodiment, when the valve body 31 is moved to the valve seat 24 side, after the slope portion 32A of the seal member 32 makes point contact with the inner peripheral edge 24A of the valve seat 24, the seal member is further removed. Since the flat surface portion 32B of the 32 is configured to come into surface contact with the seating surface 24B of the valve seat 24, the pressure applied to the valve body 31 after valve closing is dispersed from the vertical direction to the surface contact portion and a load is applied. . Thereby, the secular deformation of the sealing member 32 is suppressed, and high sealing performance can be maintained over a long period of time.

  Further, by adopting the above configuration, the valve hole 25 is sealed by the point contact between the seal member 32 and the valve seat 24 before the degree of negative pressure in the equal width portion S1 is increased. The vibration of the valve body 31 due to excessive drawing to the hole 25 side is also suppressed. Therefore, it is difficult for abnormal noise to occur when the valve is closed.

  Furthermore, since the pressure in the gap between the valve body 31 and the valve seat 24 gradually decreases as it moves from the equal width portion S1 to the reduced width portion S2, the occurrence of cavitation around the reduced width portion S2 is also suppressed. Therefore, abnormal noise is less likely to occur when the valve is closed.

  Further, since the valve body 31 is urged toward the valve seat 24 by the elastic force of the compression spring 35, the seal member 32 is pressed against the valve seat 24 by a constant pressing force. The secular deformation of the part is further suppressed, and a longer and higher sealing property can be maintained.

  Further, by providing the stepped portion S3 between the equal width portion S1 and the reduced width portion S2, the flow of the fluid is stalled, and a rapid decrease in pressure around the reduced width portion S2 is suppressed. Occurrence of cavitation around the width portion S2 is further suppressed. Therefore, abnormal noise is less likely to occur when the valve is closed.

  In addition, the inner peripheral edge 24A of the valve seat 24 is formed in a convex surface having an arcuate cross section, and the slope portion 32A of the seal member 32 and the corner portion 32C that connects the slope portion 32A and the flat portion 32B are larger in cross section than the inner periphery 24A. Since the pressure in the gap between the valve body 31 and the valve seat 24 gradually decreases as it moves from the equal width portion S1 to the reduced width portion S2, the cavitation around the reduced width portion S2 is achieved. Is further suppressed, and the vibration of the valve body 31 due to excessive pulling of the valve body 31 toward the valve hole 25 is further suppressed. Therefore, abnormal noise is less likely to occur when the valve is closed.

[Others]
The inclined angle of the inclined surface portion 32A of the seal member 32 is preferably set within a range of 45 to 60 degrees with respect to the central axis (axis line L) of the valve body 31, but the inclined surface portion 32A to the flat surface portion 32B. It may be formed in a concave surface having a cross-sectional arc shape larger in diameter than the corner portion 32C.

  In this case, when the inclined surface portion 32A comes into contact with the valve seat 24, it is difficult to apply an excessive load to the contact surface, so that the deformation of the contact surface over time is further suppressed. Therefore, the sealing performance of the valve hole 25 can be maintained longer.

  In the above-described embodiment, the case where the three-way valve 1 having the valve seal structure of the present invention is used as a flow dividing valve has been described. However, the fluid supplied to the first flow path 21 and the second flow path 22 separately. Can also be used as a mixing valve that mixes and sends the mixture to the third flow path 23.

  In addition, the valve seal structure of the present invention is not limited to the three-way valve described in the above embodiment, but is also applicable to a flow rate adjusting valve for adjusting the flow rate of one path and a simple on-off valve having no flow rate adjusting function. it can.

DESCRIPTION OF SYMBOLS 10 ... Casing 24 ... Valve seat 24A ... Inner peripheral edge 24B of valve seat ... Seat surface 25 of valve seat ... Valve hole 31 ... Valve body 32 ... Sealing member 32A ... -Slope part 32B of seal member ... Flat part L of seal member ... axis

Claims (3)

A valve seat and a valve element are provided opposite to each other on the axis of the flow path in the casing,
The inner peripheral edge of the valve seat is formed in a convex surface having an arc cross section, and the seat surface of the valve seat is formed in a planar shape extending in a direction intersecting the axis,
The valve body is provided with a seal member capable of sealing the valve hole on the inner side of the valve seat. On the outer peripheral side of the seal member, there is a tapered slope portion that decreases in diameter toward the center side of the valve hole, and a valve seat A flat surface portion facing the seating surface and extending in a direction intersecting the axis from the outer periphery on the large diameter side of the slope portion is provided,
A valve seal structure configured such that when the valve body is moved to the valve seat side, the flat surface portion contacts the seat surface of the valve seat after the slope portion contacts the inner peripheral edge of the valve seat. In the valve seal structure according to claim 1,
The valve body is a valve seal structure that is biased toward the valve seat by the elastic force of the spring. The valve seal structure according to claim 1 or 2,
The corner seal portion connecting the slope portion and the flat portion is a valve seal structure formed in a concave surface having a cross-sectional arc shape larger in diameter than the inner peripheral edge.

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