JP7365021B2 - Seal structure of rotary valve - Google Patents

Description

The present invention relates to a seal structure for a rotary valve that suppresses leakage of fluid when an outlet is closed by a valve body.

A known rotary valve includes a housing 71 and a valve body 77, as shown in FIG. 11(a). The housing 71 includes an annular wall portion 73 having a housing portion 72 . An inflow port 74 for fluid FL into the housing portion 72 is formed in the housing 71 . In addition, outlet ports 75 and 76 for the fluid FL in the storage portion 72 are formed at a plurality of locations (two locations in FIG. 11A) on the annular wall portion 73. The valve body 77 includes a cylindrical valve body 78 disposed in the housing portion 72 and is rotatably supported by the housing 71 by a shaft 79 . A movable flow path 81 is formed in the valve body portion 78 and allows the inlet 74 and the outlet ports 75 and 76 to communicate with each other. The movable flow path 81 is opened at a cylindrical outer circumferential surface 82 of the valve body portion 78 . The opening edge 81a of the movable flow path 81 on the outer peripheral surface 82 extends in the circumferential direction of the valve body 78 and in the direction along the rotation axis L1 of the valve body 77.

Then, by rotating the valve body 77, the degree of opening (opening degree) of each outlet port 75, 76 is adjusted. For example, when one of the outlet ports 75, 76 is closed, the other outlet is completely opened. The fluid FL that has flowed into the housing section 72 from the inflow port 74 flows through the movable channel 81 and then flows out of the housing section 72 through the open outlet ports 75 and 76 . Moreover, when a part of one of the outflow ports 75, 76 is opened, a part of the other one is also opened. The fluid FL that has flowed into the storage section 72 from the inflow port 74 flows through the movable channel 81 and then flows out of the storage section 72 through the outflow ports 75 and 76 .

As shown in FIGS. 11(a) and 12, in the rotary valve 70, the outlet 75 and 76 are closed by the valve body 78 and the outlet 75 is closed by the valve body 78. , 76 and the same number of packings 83 are used. Each packing 83 includes a packing body 85 having a through hole 84 and an annular seal portion 86 that surrounds the through hole 84 and protrudes from the packing body 85 . Each packing 83 is disposed between the annular wall portion 73 and the valve body portion 78, with the through hole 84 facing the outflow ports 75, 76.

When the outflow ports 75 and 76 are opened, a portion of the seal portion 86 in the circumferential direction comes into contact with the outer peripheral surface 82 of the valve body portion 78. On the other hand, although not shown, when the outflow port 75 or the outflow port 76 is closed, the seal portion 86 comes into contact with the outer circumferential surface 82 over the entire circumference. This contact attempts to prevent the fluid FL that has entered between the valve body 78 and the packing body 85 from leaking out to the outlet ports 75 and 76.

Note that a technique of arranging a packing 83 between the annular wall portion 73 and the valve body portion 78 and bringing the annular seal portion 86 into contact with the outer circumferential surface 82 of the valve body portion 78 for sealing is disclosed in Patent Document 1, for example. It is described in.

Japanese Patent Application Publication No. 2000-193104

However, in the conventional rotary valve 70, when the outlet ports 75, 76 are partially opened by the valve body 78, as shown in FIGS. , the seal portion 86 is pressed against a portion extending in a direction generally along the rotation axis L1. Further, when one of the outflow ports 75, 76 is completely opened and the other is closed by the valve body portion 78, as shown in FIG. The seal portion 86 is pressed against two portions facing each other along the rotation axis L1 and extending in the circumferential direction of the valve body portion 78, respectively. In both the partially opened and fully opened situations, the contact length of the seal portion 86 with the opening edge 81a is only about the same as the radial dimension (width) of the seal portion 86, and is short. The area of the seal portion 86 that contacts the peripheral portion of the opening edge 81a on the outer circumferential surface 82 of the valve body portion 78 is small.

Therefore, as shown in FIGS. 11(a) and 11(b), the contact surface pressure increases due to the above-mentioned local contact of the opening edge 81a with the sealing part 86, and the opening edge 81a comes into contact with the sealing part 86. A dent D1 is formed in the portion. When the outlet is partially opened, as shown in FIG. 13, the recess D1 is formed on one side (the left side in FIG. 13) of the seal portion 86 in the circumferential direction of the valve body portion 78, and At two locations separated from each other in the direction along the axis L1, it generally extends in the direction along the same rotational axis L1. On the other hand, when the outlet is fully opened, as shown in FIG. 15, the recesses D1 are located on both sides of the seal portion 86 in the direction along the rotation axis L1. The recesses D1 on each side extend in the same direction at two locations spaced apart from each other in the circumferential direction of the valve body portion 78.

When the valve body 77 is rotated and one of the outlet ports 75 and 76 is closed by the valve body 78, the seal portion 86 comes into contact with the outer circumferential surface 82 of the valve body 78 over the entire circumference, as described above. . At this time, as shown by the arrow in FIG. There is a risk that the liquid may leak into the area surrounded by the seal portion 86. The leaked fluid FL flows out from the closed outlet ports 75 and 76.

The present invention has been made in view of the above circumstances, and its purpose is to prevent fluid that has entered between the valve body and the packing body when the outflow port is closed to the seal portion in the valve body. An object of the present invention is to provide a seal structure for a rotary valve that can suppress leakage into an area surrounded by a rotary valve.

The seal structure of a rotary valve that solves the above problems includes a housing that includes an annular wall portion having a housing portion, an inlet for fluid formed therein, and an outflow port formed in the annular wall portion, and a housing that is supported by the housing. The valve body is disposed in the accommodating portion and has a movable flow path that communicates the inflow port and the outflow port, and the valve body portion is provided with a , the packing is applied to a rotary valve that adjusts the opening degree of the outlet, and includes a packing body having a through hole, and an annular seal portion protruding from the packing body surrounding the through hole. , the packing is disposed between the annular wall portion and the valve body portion with the through hole facing the outflow port, and when the outflow port is opened, a portion of the seal portion in the circumferential direction is disposed. , the outer peripheral surface of the valve body is brought into contact with a peripheral portion of the movable flow path, and when the outlet is closed, the seal portion is brought into contact with the outer peripheral surface over the entire circumference, so that the valve body and the A seal structure of a rotary valve that seals between an outlet and an outlet, wherein a portion of a surface of the packing body on the valve body side adjacent to an outer circumferential side of the seal portion has an opening for the outlet. Sometimes, an expanded seal part is provided which contacts the opening edge of the movable channel together with the seal part.

According to the above configuration, the outflow port is opened or closed by rotating the valve body.
When the outlet is opened, a portion of the seal portion in the circumferential direction comes into contact with a portion of the outer peripheral surface of the valve body around the movable flow path.

In addition, when the above-mentioned opening occurs, the expanded seal portion provided on the surface of the packing body on the valve body side adjacent to the outer circumferential side of the seal portion comes into contact with the opening edge of the movable flow path together with the seal portion. Ru. Therefore, compared to the case where only a portion of the seal portion in the circumferential direction is in contact with the outer circumferential surface of the valve body, the length of the opening edge with which the packing is contacted becomes longer by the contact of the expanded seal portion. The contact area between the packing and the outer peripheral surface of the valve body increases.

Accordingly, the contact surface pressure generated between the packing and the valve main body is reduced, and dents are less likely to occur in the packing at the portion that comes into contact with the opening edge. Therefore, even if fluid enters between the packing body and the valve body when the outlet is closed, the fluid is unlikely to leak into the area surrounded by the seal portion on the outer peripheral surface of the valve body.

In the seal structure of the rotary valve, the seal portion includes a contact portion that contacts the opening edge and a peripheral portion of the opening edge of the outer circumferential surface of the valve body when the outlet is opened. Preferably, the expansion seal portion is provided on both sides of the valve body in a direction along the rotation axis, and the expansion seal portion is provided on both sides of each contact portion in the circumferential direction of the valve body.

According to the above configuration, when the outflow port is opened, the contact portions on both sides of the seal portion in the direction along the rotation axis of the valve body are between the opening edge of the movable channel and the outer peripheral surface of the valve body. The peripheral portion of the opening edge is contacted. Further, for each contact portion, expansion seal portions provided on both sides of the valve body in the circumferential direction are brought into contact with the opening edge and the peripheral portion.

Therefore, compared to the case where only the contact part of the seal part contacts the opening edge and the surrounding area, the length of the opening edge where the packing comes into contact becomes longer due to the contact of the expanded seal part, and the packing and valve The contact area with the outer peripheral surface of the main body increases.

In the seal structure of the rotary valve, the end of the expansion seal portion opposite to the contact portion in the circumferential direction of the valve body is located at the end of the valve body of the packing body on the valve body side. Preferably, it is located at the end in the circumferential direction of the main body.

According to the above configuration, the dimension of the expanded seal portion in the circumferential direction of the valve body portion becomes the maximum possible size. Therefore, the length of the opening edge that is in contact with the expansion seal portion is increased, the area that the expansion seal portion contacts with the outer peripheral surface of the valve body and the peripheral portion of the opening edge is increased, and the packing is increased. It becomes possible to efficiently reduce the contact surface pressure between the valve body and the valve body.

According to the seal structure of the rotary valve described above, when the outflow port is closed, fluid that has entered between the valve body and the packing body is suppressed from leaking into the area surrounded by the seal in the valve body. be able to.

FIG. 1 is a perspective view showing a portion of a rotary valve in one embodiment. FIG. 3 is a partial perspective view showing a state in which a valve body and parts disposed around the valve body are taken out from an accommodating portion of a housing in one embodiment. FIG. 3 is an exploded perspective view separately showing the valve body in FIG. 2 and parts arranged around it. FIG. 2 is a perspective view of a valve body in one embodiment. FIG. 2 is a partial plan cross-sectional view of the rotary valve of FIG. 1; FIG. 6 is an explanatory diagram showing a region where the packing comes into contact with the valve body when both the first outlet and the second outlet are partially opened in one embodiment. In one embodiment, a portion showing how the seal portion and the expansion seal portion are in contact with the opening edge of the movable flow path when both the first outflow port and the second outflow port are partially opened. Perspective view. FIG. 6 is a partial plan sectional view of the rotary valve when the valve body is rotated from the state shown in FIG. 5 to open all of the second outlet and close the first outlet. FIG. 7 is an explanatory diagram showing a region where the packing contacts the valve main body when the second outlet is entirely opened in one embodiment. FIG. 7 is an explanatory diagram showing a region where the packing contacts the valve main body when the first outlet is closed in one embodiment. 11(a) is a partial vertical sectional view of a conventional rotary valve, and FIG. 11(b) is a partial longitudinal sectional view showing an enlarged part of FIG. 11(a). FIG. 2 is an exploded perspective view of a valve body and packing in a conventional rotary valve. FIG. 7 is an explanatory diagram, corresponding to FIG. 6, showing the region where the packing comes into contact with the valve body when a pair of outflow ports are both partially opened in a conventional rotary valve. FIG. 8 is a partial perspective view of the conventional rotary valve, corresponding to FIG. 7, showing a state in which the seal portion is in contact with the opening edge of the movable flow path when both of the pair of outflow ports are partially opened. FIG. 10 is an explanatory diagram showing the area where the packing contacts the valve body when one outlet is completely opened, corresponding to FIG. 9, in a conventional rotary valve. FIG. 2 is an explanatory diagram showing a fluid leakage path when one outlet is blocked in a conventional rotary valve.

An embodiment of a rotary valve seal structure will be described below with reference to FIGS. 1 to 10.
1, 5, and 8 show parts of the rotary valve 10 related to the seal structure. The rotary valve 10 is provided in the middle of a flow path of a fluid FL such as water supplied from a fluid supply source such as a pump (not shown). More specifically, this flow path includes a common flow path 11 connected to the fluid supply source, and a first branch flow path 12 and a second branch flow path 13 branched from the common flow path 11. The rotary valve 10 is arranged at a portion where the first branch flow path 12 and the second branch flow path 13 branch from the common flow path 11, and the rotary valve 10 is arranged at a portion where the first branch flow path 12 and the second branch flow path 13 diverge from the common flow path 11. It plays the role of adjusting the flow rate. By adjusting the flow rate, as shown in FIG. It is possible to flow only into the flow path 13).

The rotary valve 10 includes a housing 20 and a valve body 40. Next, each member will be explained.
<Housing 20>
As shown in FIGS. 2 and 5, the housing 20 includes an annular wall portion 22 having an annular shape, and a closing portion 23 provided in a portion of the annular wall portion 22 in the vertical direction to close the annular wall portion 22. , and a cover (not shown). The cover is disposed above the annular wall 22 and closes the upper opening of the annular wall 22. The cover is fastened to the annular wall portion 22 using fastening members such as screws. A portion surrounded by the annular wall portion 22, the closing portion 23, and the cover constitutes a housing portion 24.

In the annular wall portion 22, a plurality of locations (three locations) spaced apart from each other in the circumferential direction include an inflow port 25 for the fluid FL into the storage portion 24, and a first outflow port 28 and a second outflow port 28 for the fluid FL in the storage portion 24. An outflow port 33 is formed.

A connecting pipe portion 26 is provided at the peripheral edge of the inlet 25 in the annular wall portion 22 and projects toward the side away from the housing portion 24 . The connecting pipe portion 26 and the fluid supply source are connected by a pipe 27 having the common flow path 11 for the fluid FL.

A connecting pipe portion 29 is provided at the peripheral edge of the first outlet 28 in the annular wall portion 22 and projects toward the side away from the accommodating portion 24 . A pipe 31 having the first branch flow path 12 for the fluid FL is connected to the connecting pipe portion 29, and the fluid FL flowing out from the first outlet 28 passes through the pipe 31 to the destination where the fluid FL is used. Sent. From the peripheral edge of the first outlet 28 in the annular wall portion 22, an annular annular protrusion 32 protrudes inward of the housing portion 24.

At the peripheral edge of the second outlet 33 in the annular wall portion 22 , a connecting pipe portion 34 is provided that protrudes toward the side away from the accommodating portion 24 . A piping 35 having the second branch flow path 13 for the fluid FL is connected to the connecting pipe portion 34, and the fluid FL flowing out from the second outlet 33 passes through the piping 35 to the destination where the fluid FL is used. Sent. From the peripheral edge of the second outlet 33 in the annular wall portion 22, an annular annular protrusion 36 protrudes inward of the accommodating portion 24.

In this embodiment, the connecting tube section 29 and the connecting tube section 34 are arranged at positions that are not line symmetrical with respect to the axis of symmetry of the connecting tube section 26, but are arranged at positions where they are line symmetrical. may be done.

A bearing hole 37 that extends in the vertical direction is formed in the center of the closed portion 23 . Similarly, a bearing hole extending in the vertical direction is formed in the center portion of the cover.
<Valve body 40>
As shown in FIGS. 3 and 4, the valve body 40 includes a valve body portion 41, an upper shaft portion 38, and a lower shaft portion 39, which constitute a skeleton portion thereof. The upper shaft portion 38 projects upward from the center portion of the upper surface of the valve body portion 41 . The lower shaft portion 39 projects downward from a central portion of the lower surface of the valve body portion 41 . The valve body 40 is rotatably supported at the upper shaft portion 38 relative to the bearing hole of the cover, and rotatably supported at the lower shaft portion 39 relative to the bearing hole 37 (see FIG. 2) of the closing portion 23. There is.

The valve main body portion 41 has a cylindrical shape that extends in the vertical direction as a whole, and is disposed within the housing portion 24 as shown in FIG. 1 .
As shown in FIGS. 3 and 4, the valve body 41 includes a pair of disc-shaped end walls 42 and 43 that are spaced apart from each other in the vertical direction. Both end wall portions 42 and 43 are connected by two types of connecting portions 46 and 47 provided on their outer peripheries. The connecting portion 46 has a columnar shape extending in the vertical direction. The connecting portion 47 is provided on the opposite side of the connecting portion 46 with the rotation axis L1 of the valve body 40 interposed therebetween. This connecting portion 47 has much of the outer circumferential surface 49 of the valve body portion 41 as its own outer circumferential surface.

In the valve body 41, the portion between the end walls 42 and 43, excluding the connecting portions 46 and 47, is a movable portion that communicates the inlet 25 with the first outlet 28 and the second outlet 33. A flow path 48 is configured. The movable flow path 48 is opened at the cylindrical outer circumferential surface 49 of the valve body 41 . Most of the opening edge 48a of the movable flow path 48 on the outer circumferential surface 49 extends in the circumferential direction of the valve body 41 along the outer circumferential surface 49. Further, a portion of the opening edge 48a extends along the rotation axis L1 of the valve body 40.

The valve body 40 having the above configuration is rotated by a motor (not shown), manual operation, or the like. As a result of this rotation, as shown in FIG. and the second branch flow path 13 can be communicated with each other. Further, as shown in FIG. 8, by closing the first outlet 28 and opening the entire second outlet 33 by the valve main body 41, the common flow path 11 and the second branch flow path 13 are separated. It is possible to communicate. Although not shown, contrary to the above, by closing the second outlet 33 with the valve body 41 and opening the entire first outlet 28, the common flow path 11 and the first branch flow path 12 are closed. It is possible to communicate with Further, by rotating the valve body 40, it is possible to adjust the opening degree of each of the first outlet 28 and the second outlet 33.

<Packing 50>
A seal is created between the valve body 41 and the first outlet 28 that is closed by the valve body 41, and a seal is created between the valve body 41 and the second outlet 33 that is closed by the valve body 41. In order to seal the gap, two packings 50 are used, as shown in FIGS. 3 and 5. Each packing 50 has the same configuration. Most of each packing 50 is made of an elastic material such as rubber. The surface of each packing 50 on the side of the valve body 41 is made of a thin sheet made of fluororesin. This sheet is used to reduce the friction between the packing 50 and the valve body 41, and to reduce the load required to rotate the valve body 40.

As shown in FIGS. 3 and 6, each packing 50 includes a packing main body portion 53 and a seal portion 56. As shown in FIGS. The packing main body part 53 is a part that constitutes a skeleton part of the packing 50, and has a rectangular outer shape. Further, the packing body 53 has a plate shape whose thickness direction corresponds to the radial direction of the valve body 41 . The surface of the packing body 53 on the valve body 41 side is constituted by a curved surface 54 that curves along the outer peripheral surface 49 of the valve body 41 . On the other hand, the surface of the packing body 53 on the annular wall 22 side is configured as a flat surface.

A through hole 55 is formed in the packing main body 53 and extends in the radial direction of the valve body 40, that is, in the thickness direction of the packing main body 53. The through hole 55 is constituted by a circular hole having a diameter approximately the same as each of the first outlet 28 and the second outlet 33, and functions as a passage for the fluid FL. The diameter of the through hole 55 is smaller than the dimension of the connecting portion 47 (see FIG. 4) in the circumferential direction of the valve body portion 41. The through hole 55 is formed in a size that allows it to be closed by the connecting portion 47.

The seal portion 56 protrudes from the peripheral edge of the through hole 55 toward the valve body portion 41 on the curved surface 54 of the packing body portion 53, and has an annular shape. Here, as described above, since the curved surface 54 is curved along the outer circumferential surface 49 of the valve body 41, the seal portion 56 is also curved along the outer circumferential surface 49. It can be brought into close contact with the surface 49.

As shown in FIGS. 5 and 8, one packing 50 has a through hole 55 facing the first outlet 28 and is attached to the annular protrusion 32. placed in between. The other packing 50 is disposed between the annular wall portion 22 and the valve body portion 41 with the through hole 55 facing the second outlet 33 and attached to the annular protrusion 36 .

As shown in FIGS. 6 and 9, when the first outlet 28 is opened, a portion of the seal portion 56 in the circumferential direction serves as a contact portion 61 in the movable flow path of the outer circumferential surface 49 of the valve body portion 41. The peripheral portion of 48 is touched. Here, "at the time of opening" includes not only a state in which the entire part is opened, as shown in FIG. 9, but also a state in which a part is opened, as shown in FIG.

The contact portions 61 are located on both sides of the seal portion 56 in the direction along the rotation axis L1 of the valve body 40 (in the vertical direction in FIG. 6). This point is similar to the prior art. When the second outlet 33 is opened, contact by the contact portion 61 similar to that described above is performed.

On the other hand, when the first outlet 28 is closed, the seal portion 56 is brought into contact with the outer circumferential surface 49 of the valve body portion 41 over the entire circumference, as shown in FIG. This contact seals between the valve body 41 and the first outlet 28. Also when the second outlet 33 is closed, the space between the valve body 41 and the second outlet 33 is sealed in the same manner as described above.

As shown in FIG. 5, a biasing member 58 is disposed between the annular wall portion 22 and each packing 50 to press the packing 50 toward the valve body portion 41 side. In this embodiment, a wave spring is used as the biasing member 58.

Furthermore, as shown in FIGS. 6 and 9, a movable flow path is provided at a location adjacent to the outer circumferential side of the seal portion 56 together with the seal portion 56 when at least one of the first outlet 28 and the second outlet 33 is opened. An expanded seal portion 59 that contacts the opening edge 48a of 48 is provided. The expansion seal portion 59 targets both contact portions 61 and is provided at a portion of the curved surface 54 of the packing body portion 53 adjacent to each contact portion 61 on both sides of the valve body portion 41 in the circumferential direction. There is. In one packing 50, expansion seal portions 59 are provided at four locations. The end of each expansion seal portion 59 on the side opposite to the contact portion 61 in the circumferential direction of the valve body portion 41 is located at the end of the curved surface 54 of the packing body portion 53 in the circumferential direction.

The amount of protrusion of each expansion seal portion 59 from the packing body portion 53 is the same as the amount of protrusion of the seal portion 56 from the packing body portion 53. Further, each expansion seal portion 59 is connected to the seal portion 56 in a state where the portion of the seal portion 56 that protrudes from the packing body portion 53 has the largest amount at a portion where the amount of protrusion from the packing body portion 53 is the largest. It is formed in one piece.

Next, the operation of this embodiment configured as described above will be explained. In addition, effects that occur as a result of the action will also be explained.
5 and 7 show the state of the rotary valve 10 when the connecting portion 47 of the valve body 40 straddles a part of the first outlet 28 and a part of the second outlet 33. There is. In the first outlet 28, approximately half of the side closer to the second outlet 33 is closed by the valve body 41, and approximately half of the side farther from the second outlet 33 is open. In the second outlet 33, approximately half of the side closer to the first outlet 28 is closed by the valve body 41, and approximately half of the side farther from the second outlet 33 is open.

In this state, the fluid FL that has flowed through the common flow path 11 flows into the accommodating portion 24 through the inlet 25 . After flowing through the movable channel 48, a portion of the fluid FL passes through the open portion of the first outlet 28 and flows out into the first branch channel 12. Further, after flowing through the movable flow path 48 , the remainder of the fluid FL passes through the open portion of the second outlet 33 and flows out into the second branch flow path 13 .

However, the opening area of the first outlet 28 is smaller than when the first outlet 28 is entirely opened. Therefore, the flow rate of the fluid FL flowing into the first branch flow path 12 through the first outlet 28 is smaller than when all the first outlets 28 are opened. The same applies to the flow rate of the fluid FL flowing into the second branch flow path 13 through the second outlet 33.

Further, FIG. 8 shows a state of the rotary valve 10 when the connecting portion 47 faces only the first outlet 28. The first outlet 28 is closed by the valve body 41 . The second outlet 33 is completely opened.

In this state, the fluid FL that has flowed from the common flow path 11 through the inlet 25 into the storage section 24 flows through the movable flow path 48, passes through the second outlet 33, and flows out to the second branch flow path 13. be done. The fluid FL does not pass through the first outlet 28 and is not discharged to the first branch flow path 12.

Although not shown, when the connecting portion 47 faces only the second outlet 33, the fluid FL passes through the first outlet 28 and flows out to the first branch flow path 12, contrary to the above. be done. The fluid FL does not pass through the second outlet 33 and is not discharged to the second branch flow path 13.

Here, when at least one of the first outlet 28 and the second outlet 33 is partially open, as shown in FIGS. 6 and 9, a portion of the seal portion 56 in the circumferential direction The outer circumferential surface 49 of 41 is contacted. This part includes the contact portions 61 on both sides of the seal portion 56 in the direction along the rotation axis L1.

Further, at the time of opening, for each contact portion 61 , on the curved surface 54 of the packing body portion 53 , a contact portion is provided on both sides in the circumferential direction of the valve body portion 41 and adjacent to the outer circumferential side of the seal portion 56 . The expansion seal portion 59 is brought into contact with the outer circumferential surface 49 of the valve body portion 41 .

Furthermore, as shown in FIG. 5, when both the first outlet 28 and the second outlet 33 are partially opened, as shown in FIG. 59 is pressed against an arcuate curved portion of the opening edge 48a adjacent to each end wall 42, 43. Compared to the case where the expansion seal part 59 is not provided and only the seal part 56 is pressed against the opening edge 48a (which corresponds to the prior art), the opening in which the packing 50 is contacted by the contact of the expansion seal part 59 is The length of the edge 48a becomes longer. Accordingly, the contact area between the packing 50 and a portion of the outer peripheral surface 49 of the valve body 41 around the opening edge 48a increases.

Further, as shown in FIG. 8, when the first outflow port 28 is closed and the second outflow port 33 is completely opened, the seal portion 56 and each expansion seal portion 59 are closed, as shown in FIG. is pressed against a portion of the opening edge 48a that extends in the circumferential direction of the valve body portion 41 along each end wall portion 42, 43. In this case, as well as in the above case where both the first outlet 28 and the second outlet 33 are partially opened, when only the seal portion 56 (contact portion 61) is pressed against the opening edge 48a, In comparison, the length of the opening edge 48a with which the packing 50 comes into contact becomes longer due to the contact of the expanded seal portion 59. Accordingly, the contact area between the packing 50 and a portion of the outer peripheral surface 49 of the valve body 41 around the opening edge 48a increases.

In particular, a portion of the cylindrical outer circumferential surface 49 of the valve body 41 surrounding the movable flow path 48, in this case, the outer circumferential surface 49 of the end walls 42, 43, rotates as the valve body 40 rotates. Move in the circumferential direction. In this regard, in this embodiment, the contact portions 61 are located on both sides of the seal portion 56 in the direction along the rotation axis L1 of the valve body 40. Expansion seal portions 59 are provided adjacent to each contact portion 61 on both sides of the valve body portion 41 in the circumferential direction. Therefore, regardless of the rotation of the valve body 40, the expansion seal portion 59 can be brought into contact with the peripheral portion of the movable flow path 48 on the outer circumferential surface 49 of the valve body portion 41. Accordingly, the contact area between the packing 50 and the outer circumferential surface 49 of the valve body 41 can be increased.

Furthermore, in this embodiment, the end of each expansion seal portion 59 opposite to the contact portion 61 is located at the end of the curved surface 54 of the packing body portion 53 in the circumferential direction. For this reason, the dimension of the expansion seal portion 59 in the circumferential direction of the valve body portion 41 is the maximum that can be taken. Therefore, the area in which each expansion seal portion 59 contacts the peripheral portion of the movable flow path 48 on the outer circumferential surface 49 of the valve body portion 41 can be further increased.

As the contact area increases, the contact pressure generated between each packing 50 and the outer circumferential surface 49 decreases. In particular, as described above, by setting the dimension of the expanded seal portion 59 in the circumferential direction to the maximum possible value, the contact surface pressure can be efficiently reduced.

Therefore, according to the present embodiment, unlike the prior art, dents are less likely to occur in both the seal portion 56 and the expanded seal portion 59. Alternatively, even if a dent occurs, the extent of the dent is smaller than in the prior art.

As shown in FIG. 8, when the valve body 40 is rotated and the first outlet 28 is closed by the valve body 41, the packing 50 is located in the region Z1 indicated by halftone dots in FIG. The entire portion 56 and the four expansion seal portions 59 contact the outer circumferential surface 49 of the valve body portion 41 in a pressed state. Region Z1 includes both contact portions 61. Although not shown, the same applies when the second outlet 33 is closed by the valve body 41.

Therefore, even if the fluid FL enters between the valve body 41 and the packing body 53 when the first outlet 28 or the second outlet 33 is closed, the fluid FL will not be able to reach the outer peripheral surface 49 of the valve body 41. It is difficult to leak into the area surrounded by the seal portion 56. It is possible to suppress a phenomenon in which the fluid FL leaks from the blocked first outlet 28 to the first branch channel 12 or leaks from the blocked second outlet 33 to the second branch channel 13. .

According to this embodiment, the following effects can be obtained in addition to the above.
- If the expansion seal portion 59 is made excessively large in order to reduce the contact surface pressure, the contact surface pressure becomes excessively small, the sealing performance is deteriorated, and the fluid FL may leak. In this regard, in this embodiment, the expansion seal portion 59 is formed only in a limited area around the seal portion 56, such as a location adjacent to both sides of the contact portion 61 in the circumferential direction of the valve body portion 41. Therefore, the contact area and the contact surface pressure can be made appropriate, and it is possible to both ensure sealing performance and suppress leakage of the fluid FL.

Note that the above embodiment can also be implemented as a modified example modified as follows. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

<Matters regarding housing 20>
- The annular wall portion 22 may be formed in a ring shape different from a circular ring shape, for example, a polygonal ring shape such as a square ring shape.

- The closing part 23 may be provided in a part of the annular wall part 22 in the length direction, for example, it may be provided in the upper part. Further, the closing portion 23 may be provided at an intermediate portion in the length direction.

- The number of outflow ports in the annular wall portion 22 may be changed to one or three or more. Along with this change in the number of outlet ports, the number of packings 50 used is also changed.
- The inflow port 25 may be formed at a location different from the annular wall portion 22 in the housing 20, for example, at the closing portion 23.

<Matters regarding valve body 40>
- The opening shape of the movable flow path 48 on the outer circumferential surface 49 of the valve body portion 41 may be changed to a shape different from that in the above embodiment.

<Matters regarding packing 50>
- The fluororesin sheet in the packing 50 may be omitted.
- The outer shape of the packing main body portion 53 may be changed to a shape different from a rectangle.

- The packing main body part 53 may be formed in a shape different from a plate shape.
- The shape of the through hole 55 in the packing 50 may be changed to a shape different from a circle.
- The seal portion 56 may or may not be formed on the same axis as the through hole 55.

- The seal portion 56 may be formed in an annular shape different from the external shape of the through hole 55, for example, an elliptical annular shape, a polygonal annular shape, etc.
- The seal portion 56 may be formed at a location away from the peripheral edge of the through hole 55 on the condition that it protrudes from the packing body portion 53 toward the valve body portion 41 side while surrounding the through hole 55.

- The expansion seal portion 59 may be provided only for one contact portion 61. Also in this case, the effect of suppressing leakage of the fluid FL can be obtained compared to the case where the expansion seal portion 59 is not provided.

- The expansion seal portion 59 may be provided only on one side of the valve body portion 41 in the circumferential direction with respect to the contact portion 61. Also in this case, the effect of suppressing leakage of the fluid FL can be obtained compared to the case where the expansion seal portion 59 is not provided.

<Others>
- As the biasing member 58 that presses the packing 50 against the valve body 41, a different type of spring than a wave spring, such as a coil spring or a disc spring, may be used.

- The above sealing structure is also applicable to a type of rotary valve that performs sealing without using the biasing member 58 that presses each packing 50 against the valve body 41.
- The above seal structure can also be applied to rotary valves installed in channels through which liquids of a different type than water flow, and rotary valves installed in channels through which gases instead of liquids flow. be.

DESCRIPTION OF SYMBOLS 10... Rotary valve, 20... Housing, 22... Annular wall part, 24... Accommodating part, 25... Inflow port, 28... First outlet (outlet), 33... Second outlet (outlet), 40... Valve Body, 41... Valve body, 48... Movable channel, 48a... Opening edge, 49... Outer circumferential surface, 50... Packing, 53... Packing body, 54... Curved surface (the surface of the packing body on the valve body side) ), 55...Through hole, 56...Seal part, 59...Extended seal part, 61...Contact part, FL...Fluid, L1...Rotation axis line.

Claims (2)

The housing includes an annular wall portion having a housing portion, a fluid inlet is formed, and a fluid outlet is formed in the annular wall portion, and a valve body supported by the housing, wherein the valve body is , a rotary valve including a valve body disposed in the housing portion and having a movable flow path that communicates the inflow port and the outflow port, the opening degree of the outflow port being adjusted by rotation of the valve body; applied to
Using a packing including a packing main body having a through hole and an annular seal portion surrounding the through hole and protruding from the packing main body, with the through hole facing the outflow port, disposing the packing between the annular wall and the valve body;
When the outflow port is opened, a portion of the seal portion in the circumferential direction is brought into contact with a peripheral portion of the movable flow path on the outer circumferential surface of the valve body, while when the outflow port is closed, the seal portion is brought into contact with the peripheral portion of the movable flow path. A seal structure for a rotary valve that seals between the valve body and the outlet by contacting the outer peripheral surface over the entire circumference,
A portion of the valve body-side surface of the packing body adjacent to the outer circumferential side of the seal portion contacts the opening edge of the movable flow path together with the seal portion when the outlet is opened. An expansion seal part is provided ,
The seal portion is configured to align a contact portion that contacts the opening edge and a peripheral portion of the opening edge of the outer circumferential surface of the valve body with the rotation axis of the valve body when the outflow port is opened. It has on both sides in the direction along,
The expansion seal portion is provided on both sides of each contact portion in the circumferential direction of the valve body portion,
In the rotary valve seal structure, the expansion seal portions on both sides of one of the contact portions and the expansion seal portions on both sides of the other contact portion are spaced apart from each other in a direction along the rotation axis. An end portion of the expansion seal portion on the side opposite to the contact portion in the circumferential direction of the valve body portion is located at an end of the valve body side surface of the packing body portion in the circumferential direction of the valve body portion. The rotary valve seal structure according to claim 1 , wherein the rotary valve seal structure is located at