WO2013008268A1

WO2013008268A1 - Shaft seal structure for valve

Info

Publication number: WO2013008268A1
Application number: PCT/JP2011/003961
Authority: WO
Inventors: 克典高井; 暁長谷川; 横山　雅之
Original assignee: 三菱電機株式会社
Priority date: 2011-07-11
Filing date: 2011-07-11
Publication date: 2013-01-17
Also published as: JPWO2013008268A1; JP5335167B2

Abstract

A seal member (10) has a structure whereby a carbon material is packed into a framework of a stainless steel mesh material. The sealing member is formed with: an annular flange part (11) that engages a recess formed with a stepped part (7) formed along the inner wall surface of a through-hole (4) and with a press-fitted plate (8); a tubular part (12) that protrudes from the flange part (11) so as to taper in the direction of a fluid passage (3); and a sliding part (13) that makes contact with the outer circumferential surface of a valve shaft (6) at the inner circumferential surface side of tip of the tubular part (12).

Description

Valve shaft seal structure

The present invention relates to a shaft seal structure that suppresses fluid leakage from around the valve shaft.

Conventionally, in order to suppress leakage from the periphery of a valve shaft connected to a fluid control valve (butterfly type, poppet type, flap type, etc.), for example, in Patent Document 1, a shaft sliding support portion that supports sliding of the valve shaft A donut-shaped sealing member was provided on the surface to seal the gap around the valve shaft. For example, in Patent Document 2, the end surface of a bearing bush that rotatably supports the valve shaft is pressed against the valve and sealed.

JP 2005-120932 A JP 2001-342828 A

Conventional seal members are generally made of fluororesin (heat resistance of about 260 ° C.), so they are not suitable for use in high-temperature fluid such as an exhaust gas circulation valve that circulates exhaust gas from the engine to the intake side. It was.
On the other hand, in Patent Document 2, a bearing bush serving as a seal member is made of a carbon material that is more heat resistant than fluororesin, and can be used in a high-temperature fluid. However, since the titanium material constituting the valve has a coefficient of thermal expansion different from that of the carbon material, a gap is generated between the end surface of the bearing bush and the valve. Therefore, a bearing bracket is brought into contact with the end surface opposite to the valve pressure contact end surface of the bearing bush and this bearing bracket is urged by a thrust spring, thereby pressing the valve pressure end surface of the bearing bush against the valve to close the gap. It was in composition. Therefore, there is a problem that the configuration is complicated, the number of parts is increased, and a space required for the configuration is increased.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a valve shaft seal structure that has a simple configuration and can suppress shaft leakage even at high temperatures.

A shaft seal structure of a valve according to the present invention includes a housing in which a through hole communicating with a fluid passage provided therein is formed, a valve shaft that is inserted into the fluid passage from the through hole and drives a valve in the fluid passage, An annular flange engaged with a recess formed along the inner wall surface of the through hole, a cylindrical portion protruding from the flange along the axial direction of the valve shaft toward the fluid passage, and the cylindrical portion The seal member comprises a sliding portion that is in contact with the outer peripheral surface of the valve shaft on the inner peripheral surface side, and is configured by pressing a carbon material using a stainless steel mesh material as an aggregate.

According to the present invention, the sealing member is formed from a stainless steel mesh material and a carbon material that can be used even at high temperatures, and the engagement portion between the flange portion and the recess of the through hole and the contact portion between the sliding portion and the valve shaft Therefore, it is possible to provide a shaft seal structure with a simple configuration and capable of suppressing shaft leakage even at high temperatures.

It is a fragmentary sectional view which shows the structure of the valve for fluid control which concerns on Embodiment 1 of this invention. 3 is an enlarged cross-sectional view of a shaft seal structure of a fluid control valve according to Embodiment 1. FIG. 5 is a reference example for explaining the fluid control valve according to the first embodiment. 3 is a reference example for explaining the fluid control valve according to the first embodiment. 6 is a cross-sectional view showing a modification of the fluid control valve according to Embodiment 1. FIG.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
A fluid control valve 1 shown in FIG. 1 is a butterfly type that controls a housing 2, a fluid passage 3 provided in the housing 2, a through hole 4 communicating with the fluid passage 3, and a flow rate of fluid flowing through the fluid passage 3. A valve 5, a valve shaft 6 that is inserted into the fluid passage 3 from the through hole 4 and connected to one end side, and rotates integrally with the valve 5; a stepped portion 7 formed along the inner wall surface of the through hole 4; The annular plate 8 is press-fitted into the upper stage of the stepped portion 7 and a seal member 10 that seals the gap around the valve shaft 6. An actuator or the like (not shown) is connected to one end portion of the valve shaft 6, and the other end portion of the valve shaft 6 is rotated when the valve shaft 6 rotates about the axial direction X in response to the rotational driving force of the actuator. The valve 5 connected to is opened and closed. Hereinafter, for convenience of explanation, the connection side of the actuator or the like along the axial direction X of the valve shaft 6 is referred to as “up” and the connection side of the valve 5 is referred to as “down”.

In the first embodiment, in order to suppress the so-called shaft leakage in which the fluid flowing through the fluid passage 3 leaks to the actuator side through the gap between the outer peripheral surface of the valve shaft 6 and the housing 2 (through hole 4), the sealing member A shaft seal structure using 10 is provided.

FIG. 2 shows an enlarged view of the shaft seal structure of the fluid control valve 1. Arrow A in the figure indicates the direction of flow of the fluid that has leaked the shaft.
The seal member 10 has an annular flange portion 11 for fixing the seal member 10 to the housing 2 and a cylindrical portion 12 that protrudes in the direction of the fluid passage 3 in which axial leakage occurs and becomes tapered toward the tip. And a sliding portion 13 that comes into contact with the outer peripheral surface of the valve shaft 6 on the distal end side of the inner peripheral surface of the cylindrical portion 12. This sealing member 10 is formed by shaping a sheet-like material (hereinafter referred to as SUS mesh) made of stainless steel (JIS SUS304, SUS310, etc.) wire into a mesh shape into the shape of the sealing member 10 shown in the figure. The aggregate is composed of carbon material. Since the carbon material is a material that can be used at a high temperature of about 650 ° C. and the SUS mesh can be used at a high temperature of 650 ° C. or higher, the seal member 10 can be used in a high-temperature fluid at about 650 ° C. Moreover, since the SUS mesh has a spring property, the flexibility of the seal member 10 can be adjusted by adjusting the amount or mesh density of the SUS mesh. Further, since the carbon material closes the gap of the SUS mesh, the seal member 10 does not allow fluid to pass.

The flange 11 is a portion that supports the seal member 10 by engaging with an annular recess formed by the stepped portion 7 of the housing 2 and the plate 8. Therefore, the support part 11 is ensured by adopting a configuration in which the heel part 11 has a structure in which more SUS mesh is disposed and hardened than the carbon material. 2, sealing is performed at a contact portion between the flange portion 11 and the stepped portion 7, and sealing is also performed at a contact portion between the flange portion 11 and the plate 8.
In the illustrated example, the recess for engaging and fixing the flange portion 11 is configured by the staircase portion 7 and the plate 8, but is not limited thereto, and the flange portion 11 is sandwiched from above and below. What is necessary is just a structure to fix.

The sliding portion 13 is a part of the inner peripheral surface of the cylindrical portion 12 (shown by dotted lines in FIG. 2), and abuts on the outer peripheral surface of the valve shaft 6 for sealing. Therefore, the sliding portion 13 has a configuration in which a carbon material having a good sliding property is disposed more than the SUS mesh and is compacted to ensure the sliding property. Moreover, corrosion, adhesion, etc. of the sliding part 13 can be suppressed by arrange | positioning many carbon materials.
Furthermore, in order to ensure the sealing performance of the sliding portion 13, the inner diameter of the sliding portion 13 is set smaller than the outer diameter of the valve shaft 6.

The bending part 14 which is a connection part of the collar part 11 and the cylindrical part 12 is formed by bending and shaping a sheet-like SUS mesh and pressing and solidifying a carbon material. The amount of SUS mesh (or mesh density) disposed in the bent portion 14 is adjusted to ensure the flexibility of the tubular portion 12. By ensuring the flexibility, the cylindrical portion 12 bends and deforms and the sliding portion 13 follows the valve shaft 6 even when the valve shaft 6 is displaced during the operation of the valve shaft 6. It becomes like this. Therefore, the sealing property of the sliding part 13 can be maintained.
As the tendency, the more the amount of SUS mesh is increased, the more difficult it is to bend. Therefore, the amount of SUS mesh in the collar portion 11 of the seal member 10 is maximized, and the bending portion 14 is preferably adjusted to a smaller amount.

Further, by ensuring the flexibility of the cylindrical portion 12, the fluid control valve 1 becomes a high temperature (˜650 ° C.) or a low temperature, and the sliding portion 13 has a linear expansion coefficient difference between the valve shaft 6 and the seal member 10. Even when the tightening margin is changed, the sliding portion 13 can be sealed while being in contact with the valve shaft 6. For example, when the valve shaft 6 thermally expands larger than the seal member 10 at a high temperature, the sliding portion 13 tightens the valve shaft 6 if there is no flexibility, and the sliding resistance increases. On the other hand, if the flexibility is ensured as in the first embodiment, the valve shaft 6 can be kept in contact with the increase in sliding resistance being suppressed.

Further, as shown in FIG. 2, the thickness D in the radial direction of the cylindrical portion 12 is made thinner than the thickness C in the axial direction X of the flange portion 11. Thereby, the cylindrical part 12 becomes easier to bend, and the seal | sticker by the sliding part 13 can be made more reliable. Further, the thickness D in the radial direction of the cylindrical portion 12 may not be constant, and may be formed so as to become thinner toward the tip.

Further, as shown in FIG. 2, the length E in the axial direction X of the cylindrical portion 12 is at least twice as long as the thickness C of the flange portion 11 in the axial direction X to ensure flexibility.
On the other hand, the example at the time of making the length of the axial direction X of the collar part 11 and the cylindrical part 12 the same is shown in FIG. When the pressure of the fluid leaking from the shaft is applied to the seal member 10 (indicated by arrows A and F in FIG. 3), the cylindrical portion 12 is warped and a gap is formed between the sliding portion 13 and the valve shaft 6. Occurs. Then, as the fluid pressure is applied, the sliding portion 13 is separated from the valve shaft 6 to widen the gap, and the amount of leakage increases.
On the other hand, as shown in FIG. 2, by adjusting the length E of the cylindrical portion 12 to ensure flexibility, even when a large fluid pressure is applied, warping is unlikely to occur and shaft leakage can be suppressed.

Further, since the outer shape of the cylindrical portion 12 is tapered to make it easy to receive the pressure of the fluid that has leaked the shaft, the outer peripheral surface of the cylindrical portion 12 receives the fluid pressure to the inner side when the fluid is high pressure. To bend easily (indicated by arrow B in FIG. 2). Therefore, even in the high-pressure fluid, the sliding portion 13 can be brought into contact with the valve shaft 6 and sealed to suppress shaft leakage.
Moreover, it can also be set as the structure sealed using a fluid pressure by improving the flexibility, for example by making thickness D of the radial direction of the cylindrical part 12 still thinner.
In the example of FIG. 2, a large amount of carbon material is disposed on the tip portion (sliding portion 13) of the inner peripheral surface of the cylindrical portion 12, but the carbon material is increased on the entire inner peripheral surface of the cylindrical portion 12. It may be arranged. Thereby, even if it receives the pressure of the fluid and the cylindrical part 12 will be in the state pressed on the valve shaft 6, slidability can be ensured.

As described above, since the engagement portion between the flange portion 11 of the seal member 10 and the stepped portion 7 and the plate 8 and the contact portion between the sliding portion 13 and the valve shaft 6 are always sealed, axial leakage around the valve shaft 6 is prevented. Can be suppressed. Further, since the sealing member 10 is made of SUS mesh and carbon material, it can be used at high temperatures (up to 650 ° C.). In addition, the number of parts can be reduced and the required space can be reduced as compared with the structure described in Patent Document 2 described above.

In addition, it is preferable that the seal member 10 does not contact the housing 2 with portions other than the flange portion 11 sandwiched and fixed between the staircase portion 7 and the plate 8. In FIG. 2, the cylindrical portion 12 is formed so as to be tapered toward the tip, so that the outer peripheral surface of the cylindrical portion 12 does not contact the housing 2. That is, even when the valve shaft 6 is displaced or inclined, or when the valve shaft 6 and the seal member 10 are thermally expanded, a gap is provided so that the housing 2 and the cylindrical portion 12 do not contact each other.

FIG. 4 shows an example in which a portion other than the flange 11 is brought into contact with the housing 2. When the outer peripheral surface of the cylindrical portion 12 is in contact with the housing 2 as shown in FIG. 4, there is no escape space for the force (indicated by the arrow G in FIG. 4) generated by thermal expansion and the inclination of the valve shaft 6. Therefore, the reaction force from the housing 2 is transmitted to the valve shaft 6 through the sliding portion 13 (indicated by an arrow H in FIG. 4), and the sliding resistance increases.
On the other hand, an increase in sliding resistance between the valve shaft 6 and the sliding portion 13 can be avoided by preventing the portions other than the flange portion 11 from contacting the housing 2 as shown in FIG.

Further, as shown in FIG. 2, it is preferable to set the outer diameter of the flange portion 11 to be smaller than the inner diameter of the staircase portion 7 and provide a gap between the flange portion 11 and the staircase portion 7. Since the flange portion 11 is sandwiched from above and below, it cannot thermally expand in that direction, so this gap becomes a refuge.

The sealing member 10 shown in FIG. 2 has a configuration in which the inner peripheral surface of the cylindrical portion 12 is tapered and the tip portion thereof is brought into contact with the valve shaft 6 as the sliding portion 13, but is not limited thereto. It is not a thing. For example, as shown in FIG. 5, the inner peripheral surface may have a straight shape, and the entire inner peripheral surface of the cylindrical portion 12 may be brought into contact with the valve shaft 6 as the sliding portion 13. In the case of this configuration, since the seal area becomes large, shaft leakage can be further suppressed.
Of course, configurations other than those illustrated in FIGS. 2 and 5 may be used. The area of the sliding portion 13 may be appropriately set according to the actuator driving force of the fluid control valve 1 to which the seal member 10 is applied, the allowable amount of shaft leakage, the fluid pressure, and the like.

As described above, according to the first embodiment, the fluid control valve 1 is inserted into the fluid passage 3 from the housing 2 in which the through hole 4 communicating with the fluid passage 3 provided therein is formed, and the through hole 4. An annular flange engaged with a recess formed by a valve shaft 6 for driving the valve 5 in the fluid passage 3, a stepped portion 7 formed along the inner wall surface of the through hole 4 and a press-fitted plate 8. 11. A cylindrical portion 12 protruding from the flange portion 11 in the direction of the fluid passage 3 along the axial direction X, and a sliding portion that contacts the outer peripheral surface of the valve shaft 6 on the inner peripheral surface side of the cylindrical portion 12 And a sealing member 10 composed of a SUS mesh as an aggregate and a carbon material pressed and hardened. For this reason, shaft leakage can be suppressed from a low temperature to a high temperature (up to 650 ° C.) with a simple configuration.

Further, according to the first embodiment, the seal member 10 has a shape in which the flange portion 11 is in contact with the housing 2, and the cylindrical portion 12 and the sliding portion 13 are not in contact with the housing 2. The sliding resistance can be reduced at the contact portion between the valve shaft 6 and the valve shaft 6.

Further, according to the first embodiment, the sealing member 10 secures the strength of the flange portion 11 because the radial thickness D of the cylindrical portion 12 is made thinner than the thickness C of the flange portion 11 in the axial direction X. At the same time, the flexibility of the cylindrical portion 12 and the sliding portion 13 can be ensured. In addition, the cylindrical portion 12 is easily deformed in the direction of the valve shaft 6 due to the fluid pressure, and even when the fluid pressure is high, the sliding portion 13 is in close contact with the valve shaft 6 and shaft leakage can be suppressed.

Further, according to the first embodiment, the seal member 10 has the cylindrical portion 12 with the length E in the axial direction X of the cylindrical portion 12 more than twice the thickness C of the flange portion 11 in the axial direction X. The flexibility of 12 and the sliding part 13 is securable. Moreover, even if it receives fluid pressure, it can be set as the structure where the curvature of the cylindrical part 12 does not occur easily.

Further, according to the first embodiment, since the carbon material is disposed more on the sliding portion 13 of the seal member 10 than the SUS mesh, the sliding property of the sliding portion 13 can be ensured.

Moreover, according to Embodiment 1, since the sealing member 10 adjusted the quantity of the SUS mesh arrange | positioned in the bending part 14 which is the connection part of the collar part 11 and the cylindrical part 12, it ensured the flexibility. The sliding portion 13 can come into contact with the valve shaft 6 even when the shaft 6 is in operation or the interference or clearance between the valve shaft 6 and the sliding portion 13 changes due to thermal expansion, thereby suppressing shaft leakage. be able to.

In the above description, the seal member 10 is applied to the valve shaft 6 that rotates about the axial direction X. However, the present invention is not limited to this, and the valve moves linearly along the axial direction X. The seal member 10 can also be applied to the shaft. Further, the shape of the valve 5 is not limited to the butterfly type, and may be any shape such as a poppet type and a flap type.
In addition to this, the present invention can be modified in any component of the embodiment or omitted in any component within the scope of the invention.

As described above, the shaft seal structure of the valve according to the present invention is such that the seal member is formed from the SUS mesh and the carbon material that can be used even at high temperatures. Suitable for use in.

1 Valve for fluid control, 2 housing, 3 fluid passage, 4 through hole, 5 valve, 6 valve shaft, 7 staircase section, 8 plate, 10 seal member, 11 collar section, 12 cylindrical section, 13 sliding section, 14 Bending part.

Claims

A housing in which a through hole communicating with a fluid passage provided inside is formed;
A valve shaft that is inserted into the fluid passage from the through hole and drives a valve in the fluid passage; and
An annular flange engaged with a recess formed along the inner wall surface of the through hole, a cylindrical portion protruding from the flange along the axial direction of the valve shaft toward the fluid passage, and the cylinder A valve shaft comprising a sliding portion that is in contact with the outer peripheral surface of the valve shaft on the inner peripheral surface side of the shaped portion, and is configured by pressing a carbon material with a stainless steel mesh material as an aggregate. Seal structure.
The valve shaft seal structure according to claim 1, wherein the seal member has a shape in which the flange portion contacts the housing, and the cylindrical portion and the sliding portion do not contact the housing.
2. The valve shaft seal structure according to claim 1, wherein the seal member has a shape in which a radial thickness of the cylindrical portion is thinner than a thickness of the flange portion in the axial direction.
2. The valve shaft seal according to claim 1, wherein the seal member has a shape in which a length of the cylindrical portion in the axial direction is twice or more a thickness of the flange portion in the axial direction. Construction.
2. The valve shaft seal structure according to claim 1, wherein the sliding portion of the seal member is provided with more carbon material than stainless steel mesh material.
2. The valve according to claim 1, wherein the seal member is configured to adjust the amount of a stainless steel mesh material disposed at a connection portion between the flange portion and the cylindrical portion to ensure flexibility. Shaft seal structure.