JP2024073868A - Flow Switching Device - Google Patents

Abstract

[Problem] To provide a flow path switching device capable of ensuring sealing by a seal member. [Solution] In one aspect of the present disclosure, a flow path switching device 1 has a seal member 81 that is provided around a rotating disk communication passage 60 so as to protrude toward a fixed disk 50 and seals between the rotating disk 40 and the fixed disk 50, the seal member 81 being formed of a circumferential sliding portion 91 formed along the rotation direction of the rotating disk 40 and a shear sliding portion 92 connecting two circumferential sliding portions 91 arranged in a direction perpendicular to the rotation direction of the rotating disk 40, and a tip 91a of the circumferential sliding portion 91 is less likely to be displaced than a tip 92a of the shear sliding portion 92. [Selected Figure] FIG.

Description

The present disclosure relates to a flow path switching device that switches a flow path through which a fluid flows.

Patent Document 1 discloses a flow path switching valve in which a rotor seal on the rotor slides against a stator when the rotor rotates.

JP 2020-144027 A

In the flow path switching valve disclosed in Patent Document 1, when the rotor seal passes through the stator flow path, a non-contact portion of the rotor seal is released into the stator flow path and does not contact the stator, and a contact portion is in contact with the stator. Therefore, when the non-contact portion of the rotor seal moves from inside the stator flow path onto the surface of the stator, a catch occurs at the boundary between the non-contact portion and the contact portion of the rotor seal, resulting in stress concentration. This causes the rotor seal to wear, which may reduce the sealing ability of the rotor seal.

Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a flow path switching device that can ensure sealing by the sealing member.

One embodiment of the present disclosure made to solve the above problem is a flow path switching device having a fixed member and a drive member, which is driven by the drive member to switch the combination of ports of the fixed member and the communication passages of the drive member to communicate with each other, thereby switching the flow path through which a fluid flows. The drive member is provided around the communication passage of the drive member so as to protrude toward the fixed member, and is provided with a seal member for sealing between the drive member and the fixed member, and the seal member is formed of a first portion formed along the drive direction of the drive member and a second portion connecting two of the first portions arranged in a direction perpendicular to the drive direction of the drive member, and the cross-sectional shape tip of the first portion is less likely to be displaced than the cross-sectional shape tip of the second portion.

According to this aspect, the cross-sectional tip of the first portion of the seal member is less likely to displace. Therefore, when the drive member is driven and the cross-sectional tip of the second portion of the seal member passes the port of the fixed member, the amount of displacement of the cross-sectional tip of the first portion can be suppressed. Therefore, the amount of protrusion of the cross-sectional tip of the second portion released in the port of the fixed member into the port can be suppressed. Therefore, when the drive member is further driven and the cross-sectional tip of the second portion of the seal member rides up from inside the port onto the surface of the fixed member, the ride-up angle can be suppressed, and stress concentration in the seal member can be alleviated.

In addition, because the tip of the cross-sectional shape of the second portion of the sealing member is easily deformed, the ride-on angle can be more effectively suppressed. As a result, stress concentration in the sealing member can be more effectively alleviated.

In this way, stress concentration in the sealing member can be alleviated, preventing breakage and wear of the sealing member, thereby ensuring the sealing performance of the sealing member.

In the above aspect, it is preferable that the tip of the cross-sectional shape of the first portion is formed with a flat portion, and the tip of the cross-sectional shape of the second portion is entirely formed with an R-shape.

According to this aspect, the tip of the cross-sectional shape of the first part is less likely to be displaced because a flat portion is formed at the tip of the cross-sectional shape of the first part, while the tip of the cross-sectional shape of the second part is more likely to be displaced because the entire tip of the cross-sectional shape is formed in an R shape. Therefore, it is more reliably possible for the tip of the cross-sectional shape of the first part to be less likely to be displaced than the tip of the cross-sectional shape of the second part.

In the above aspect, it is preferable that a groove is formed in the flat surface.

According to this aspect, when the fluid is liquid, the liquid flows into the groove, making it easier to form a liquid film between the flat portion of the tip of the cross-sectional shape of the first portion and the fixed member, thereby reducing the sliding resistance between the tip of the cross-sectional shape of the first portion and the fixed member.

In the above embodiment, it is preferable to provide a convex portion on the edge of the opening side of the groove.

According to this aspect, the convex portion improves the ability of the tip of the cross-sectional shape of the first portion of the sealing member to conform to the surface of the fixed member, so that the sealing performance of the first portion of the sealing member can be maintained.

In the above aspect, it is preferable to provide fine irregularities on the flat surface and/or on the contact portion of the fixing member with the flat surface.

According to this aspect, when the fluid is liquid, it becomes easier to form a liquid film between the tip of the cross-sectional shape of the first portion and the surface of the fixed member, and the sliding resistance generated between the tip of the cross-sectional shape of the first portion and the surface of the fixed member can be reduced.

In the above aspect, it is preferable that the width of the planar portion gradually decreases as it approaches the second portion.

According to this aspect, in the first section, the contact width between the flat portion of the tip of the cross-sectional shape of the first section and the fixed member gradually decreases toward the second section. This reduces the sliding resistance between the first section and the fixed member.

In the above aspect, it is preferable that when the sealing member is in a free state, the cross-sectional shape tip of the second portion is formed to protrude beyond the cross-sectional shape tip of the first portion.

According to this aspect, a certain level of surface pressure can be applied to the fixing member at the tip of the cross-sectional shape of the second portion. This improves the sealing performance at the second portion.

In the above aspect, it is preferable that the seal member is integrally molded with the driving member, and an elastic member that comes into contact with the seal member is provided on the surface of the fixed member that faces the seal member.

According to this aspect, the outer diameter of the drive member can be reduced by integrally molding the seal member with the drive member so that the seal member is as close as possible to the edge of the communication passage of the drive member. This allows the outer diameter of the fixed member to be reduced, making it possible to miniaturize the flow path switching device.

In the above aspect, it is preferable to change the stop position of the driving member under predetermined conditions.

According to this aspect, even if the driving member is stopped for a long period of time, it is possible to prevent the elastic member from becoming worn due to pressure from the sealing member.

The flow path switching device disclosed herein ensures sealing performance using the sealing member.

FIG. 2 is an external perspective view of the flow path switching device of the present embodiment (when it is a six-way valve). FIG. 2 is an exploded perspective view of the flow path switching device of the present embodiment (a drive unit and a control unit are not shown). 1 is a cross-sectional view of a flow path switching device according to an embodiment of the present invention (a drive unit and a control unit are not shown). FIG. 2 is a top view of the rotating disk. FIG. FIG. 2 is a diagram illustrating a first flow path pattern, showing an image of the flow path switching device as viewed from above; FIG. 13 is a diagram illustrating a second flow path pattern, showing an image of the flow path switching device as viewed from above. 11 is a cross-sectional view of the housing, the rotating disk, and the fixed disk, showing the state when the seal member passes through the fixed disk communication passage; FIG. 13 is a diagram showing the seal member and the fixed disk communication passage when the seal member passes through the fixed disk communication passage; FIG. FIG. 2 is a diagram showing a seal member and its periphery on the lower surface of a rotating disk, illustrating a circumferential sliding portion and a shear sliding portion of the seal member. FIG. 4 is a diagram showing a tip of a circumferential sliding portion of a seal member in the first embodiment. 5 is a diagram showing a tip of a shear sliding portion of a seal member in the first embodiment. FIG. 10A and 10B are diagrams illustrating a state in which a load is applied to a tip of a circumferential sliding portion of a seal member in the first embodiment. 10A and 10B are diagrams illustrating a state in which a load is applied to a tip of a shear sliding portion of a seal member in the first embodiment. FIG. 10 is a diagram illustrating the state when the shear sliding portion of the seal member is released into the fixed disk communication passage in the first embodiment, and is a diagram illustrating the protrusion amount of the shear sliding portion. FIG. 13 is a diagram illustrating a state in which the shear sliding portion of the seal member is released into the fixed disk communication passage in the comparative example, and is a diagram illustrating the protrusion amount of the shear sliding portion. FIG. 11 is a diagram showing the state in which the shear sliding portion of the seal member rides up from within the fixed disk communication passage onto the upper surface of the fixed disk in the first embodiment, and is a diagram showing the ride-up angle of the shear sliding portion. FIG. 13 is a diagram showing the state in which the shear sliding portion of the seal member rides up from within the fixed disk communication passage onto the upper surface of the fixed disk in the comparative example, and is a diagram showing the ride-up angle of the shear sliding portion. FIG. 13 is an image diagram for explaining the water film breakage. 13 is a diagram showing a groove provided in a flat portion at the tip of a circumferential sliding portion of a seal member in a second embodiment. FIG. 13 is a diagram showing a structure in which a minute protrusion is provided on the edge of the opening side of a groove in the third embodiment. FIG. FIG. 13 is a diagram showing that, in the fourth embodiment, when the seal member is in a free state, the tip of the shear sliding portion is formed to protrude beyond the tip of the circumferential sliding portion. FIG. 13 is a diagram showing how, in a fifth embodiment, fine irregularities are provided on the flat surface of the tip of the circumferential sliding portion of the seal member, while the tip of the shear sliding portion of the seal member is mirror-finished. FIG. 13 shows a fifth embodiment in which fine irregularities are provided on the upper surface of the fixed disk at the contact portion between the tip of the circumferential sliding portion of the sealing member and the flat portion, while the contact portion between the tip of the shear sliding portion of the sealing member and the flat portion is mirror-finished. 13A is a cross-sectional view of the housing, the rotating disk, and the fixed disk in the sixth embodiment, and FIG. 13B is a cross-sectional view of the housing, the rotating disk, and the fixed disk in the first embodiment and the like. 13A to 13C are diagrams showing cross-sectional positions of a seal member in a seventh embodiment; 13A to 13C are diagrams showing the shape of the tip of a circumferential sliding portion at each cross-sectional position of a seal member in a seventh embodiment. 13 is a diagram showing the wear of a rubber sheet caused by the rotation disk being stopped for a long period of time. FIG. FIG. 23 is a flowchart showing the contents of control performed in the eighth embodiment.

We will now explain the flow path switching device 1, which is an example of an embodiment of the present disclosure.

<Overall Overview of Flow Path Switching Device>
First, an overview of the flow path switching device 1 of the present embodiment will be described.

As shown in Figures 1 to 3, the flow path switching device 1 has a housing 11, a valve body section 12, a drive section 13, and a control section 14.

The housing 11 has an inflow flow path 20 through which the fluid flows in, and an outflow flow path 30 through which the fluid flows out. Here, the flow path switching device 1 is, as an example, a six-way valve, and the housing 11 has three inflow flow paths 20 and three outflow flow paths 30. The three inflow flow paths 20 include a first inflow flow path 21, a second inflow flow path 22, and a third inflow flow path 23. The three outflow flow paths 30 include a first outflow flow path 31, a second outflow flow path 32, and a third outflow flow path 33.

The housing 11 is formed, for example, from resin. The housing 11 is an example of a "fixed member" in the present disclosure, and the inlet flow passage 20 (i.e., the first inlet flow passage 21, the second inlet flow passage 22, and the third inlet flow passage 23) is an example of a "port" in the present disclosure.

The valve body portion 12 is provided inside the housing 11. As shown in Figures 2 and 3, this valve body portion 12 includes a rotating plate-shaped rotating disk 40 and a plate-shaped fixed disk 50. The rotating disk 40 and the fixed disk 50 are stacked and arranged in the direction of the central axis L (hereinafter simply referred to as the "axial direction") of the disk portion 41 of the rotating disk 40 and the disk portion 51 of the fixed disk 50, which will be described later.

The rotating disk 40 and the fixed disk 50 are formed, for example, from resin. The rotating disk 40 is an example of a "driving member" in this disclosure, and the fixed disk 50 is an example of a "fixed member" in this disclosure.

As shown in Figures 2 to 4, the rotating disk 40 is disposed between the housing 11 and the fixed disk 50, and is sandwiched between the housing 11 and the fixed disk 50, with stress due to the pressing force of the disk holding spring 82 (described later) acting via the fixed disk 50 and a sealing member 81 (described later). The rotating disk 40 includes a disk portion 41 and a rotating shaft portion 42.

The disk portion 41 is formed in a disk shape and includes a rotating disk communication passage 60. This rotating disk communication passage 60 penetrates the disk portion 41 in the axial direction and can communicate with the inflow passage 20 and the fixed disk communication passage 70 described later. Here, the disk portion 41 includes three rotating disk communication passages 60. As shown in FIG. 2 and FIG. 4, the three rotating disk communication passages 60 include a first rotating disk communication passage 61, a second rotating disk communication passage 62, and a third rotating disk communication passage 63. The rotating disk communication passages 60 (i.e., the first rotating disk communication passage 61, the second rotating disk communication passage 62, and the third rotating disk communication passage 63) are an example of a "communication passage" in this disclosure.

The rotating shaft portion 42 is connected to the disk portion 41 at one end in the direction of its central axis, and is connected to the drive unit 13 at the other end. The rotating shaft portion 42 is provided at the center of the disk portion 41 so that its central axis coincides with the central axis L of the disk portion 41. The rotating shaft portion 42 rotates around its central axis upon receiving rotational power from the drive unit 13, causing the disk portion 41 connected to the rotating shaft portion 42 to rotate around its central axis L. In this way, the rotating disk 40 rotates around the central axis L by receiving rotational power from the drive unit 13.

As shown in Figures 2, 3, and 5, the fixed disk 50 has a disk portion 51 and a cylindrical portion 52.

The disk portion 51 is formed in a disk shape and has a fixed disk communication passage 70 that penetrates in the axial direction. Here, the disk portion 51 has three fixed disk communication passages 70. As shown in Figures 2 and 5, the three fixed disk communication passages 70 include a first fixed disk communication passage 71, a second fixed disk communication passage 72, and a third fixed disk communication passage 73. The fixed disk communication passages 70 (i.e., the first fixed disk communication passage 71, the second fixed disk communication passage 72, and the third fixed disk communication passage 73) are an example of a "port" in this disclosure.

The cylindrical portion 52 is connected to the disk portion 51 and is formed to extend axially from the disk portion 51 so as to surround the fixed disk communication passage 70. Here, three cylindrical portions 52 are formed to correspond to the three fixed disk communication passages 70.

The drive unit 13 is equipped with a motor (not shown) for providing rotational power to the rotating shaft portion 42 of the rotating disk 40.

The control unit 14 includes, for example, a CPU and memory such as ROM and RAM, and controls the flow path switching device 1 according to a program pre-stored in the memory.

The flow path switching device 1 configured as described above forms a flow path through which the fluid flows by connecting the inflow flow path 20, the rotating disk communication path 60, and the fixed disk communication path 70 (outflow flow path 30). The flow path switching device 1 then rotates the rotating disk 40 using the drive unit 13 to switch the combination of the inflow flow path 20, the fixed disk communication path 70, and the rotating disk communication path 60 that are connected, thereby switching the pattern of the flow path through which the fluid flows.

For example, as shown in FIG. 6, as a first flow path pattern, three rotating disk communication paths 60 (i.e., a first rotating disk communication path 61, a second rotating disk communication path 62, and a third rotating disk communication path 63) communicate the first inflow path 21 with the first fixed disk communication path 71 (first outflow path 31), communicate the second inflow path 22 with the second fixed disk communication path 72 (second outflow path 32), and communicate the third inflow path 23 with the third fixed disk communication path 73 (third outflow path 33).

Then, the rotating disk 40 can be rotated counterclockwise by the drive unit 13 from the first flow path pattern state shown in FIG. 6 to switch to the second flow path pattern shown in FIG. 7.

That is, as shown in FIG. 7, in the second flow path pattern, three rotating disk communication paths 60 connect the first inflow path 21 to the third fixed disk communication path 73 (third outflow path 33), connect the second inflow path 22 to the first fixed disk communication path 71 (first outflow path 31), and connect the third inflow path 23 to the second fixed disk communication path 72 (second outflow path 32).

The flow path pattern shown in FIG. 7 can be switched to the first flow path pattern shown in FIG. 6 by rotating the rotary disk 40 clockwise using the drive unit 13. The flow path switching device 1 is not limited to a six-way valve, and can also be a multi-way valve such as a three-way valve or a four-way valve.

In addition, in this embodiment, elastic members are provided in the axial direction between the housing 11 and the rotating disk 40, between the rotating disk 40 and the fixed disk 50, and between the fixed disk 50 and the housing 11.

Specifically, as shown in FIG. 3, between the housing 11 and the rotating disk 40, and between the rotating disk 40 and the fixed disk 50, sealing members 81 are provided as elastic members for sealing between the housing 11 and the rotating disk 40, and between the rotating disk 40 and the fixed disk 50.

As shown in Figures 2 to 4, the seal member 81 is provided circumferentially on the upper surface 41a and the lower surface 41b of the disk portion 41 of the rotating disk 40 so as to surround the periphery of the rotating disk communication passage 60 formed in the shape of an elongated hole. The seal member 81 provided on the upper surface 41a of the disk portion 41 is provided so as to protrude toward the housing 11, and contacts the housing 11 to seal (seal) the flow passage formed between the inflow flow passage 20 and the rotating disk communication passage 60 communicating with the inflow flow passage 20 from the outside. The seal member 81 provided on the lower surface 41b of the disk portion 41 contacts the fixed disk 50 to seal the flow passage formed between the fixed disk communication passage 70 and the rotating disk communication passage 60 communicating with the fixed disk communication passage 70 from the outside.

The sealing member 81 is formed, for example, from a fluororesin (e.g., Teflon (registered trademark)). The sealing member 81 may also be formed from rubber to which a fluororesin is attached. Furthermore, the sealing member 81 may also be formed from a material other than fluororesin or rubber.

A disk holding spring 82 is provided as an elastic member between the disk portion 51 of the fixed disk 50 and the housing 11. The stress caused by the pressing force of this disk holding spring 82 acts on the disk portion 51 of the fixed disk 50. A total of three such disk holding springs 82 are provided, one on each of the three cylindrical portions 52 of the fixed disk 50. The three disk holding springs 82 are provided at equal intervals from each other.

A lip seal 83 is provided between the cylindrical portion 52 of the fixed disk 50 and the housing 11 to ensure sealing of the fixed disk communication passage 70.

<Regarding sealing materials>
Next, the seal member 81 will be described. In this embodiment, the seal member 81 is provided on both the upper surface 41a and the lower surface 41b of the rotating disk 40, but in the following description, the seal member 81 provided on the lower surface 41b will be described as a representative. Therefore, the following description can also be applied to the seal member 81 provided on the upper surface 41a, i.e., the seal member 81 that slides on the surface 11a of the housing 11.

As shown in Figures 8 and 9, when the rotating disk 40 rotates in its circumferential direction to switch the flow path, a part of the seal member 81 passes through the fixed disk communication passage 70, which is a port of the fixed disk 50. Therefore, there are parts of the seal member 81 that always slide over the upper surface 51a (of the disc portion 51) of the fixed disk 50 without passing through the fixed disk communication passage 70, and parts that slide over the upper surface 51a of the fixed disk 50 and pass through the fixed disk communication passage 70.

Here, as shown in FIG. 10, it is considered that the sealing member 81 is formed of a circumferential sliding portion 91 and a shear sliding portion 92. In other words, it is considered that the sealing member 81 is formed in a track shape and is formed of two circumferential sliding portions 91 and two shear sliding portions 92.

The circumferential sliding portion 91 is a portion that always slides on the upper surface 51a of the fixed disk 50 without passing through the fixed disk communication passage 70, and is a portion that is formed along the circumferential direction (i.e., the rotational direction) of the rotating disk 40 (i.e., the portion of region α in FIG. 10). When the rotating disk 40 rotates, this circumferential sliding portion 91 slides on the upper surface 51a of the fixed disk 50 along the rotational direction of the rotating disk 40. The circumferential sliding portion 91 is also an example of the "first portion" of the present disclosure.

The shear sliding portion 92 is defined as a portion that slides over the upper surface 51a of the fixed disk 50, passes through the fixed disk communication passage 70, and is released into the fixed disk communication passage 70, and is defined as a portion that connects two circumferential sliding portions 91 arranged in a direction perpendicular to the rotation direction of the rotating disk 40 (i.e., the portion of region β in FIG. 10). When the rotating disk 40 rotates, this shear sliding portion 92 slides over the upper surface 51a of the fixed disk 50, generating shear stress. The shear sliding portion 92 is also an example of a "second portion" in the present disclosure.

9 and 10, for the sake of explanation, the rotational direction (circumferential direction) of the rotating disk 40 is shown as a straight line extending from left to right in the drawing. Also, in FIG. 9, the range of the trajectory along which the fixed disk communication passage 70 can move relative to the seal member 81 as the rotating disk 40 rotates is shown as TR.

Here, when the shear sliding portion 92 passes through the fixed disk communication passage 70, it is released into the fixed disk communication passage 70. Therefore, the tip 92a (on the fixed disk 50 side) of the shear sliding portion 92 protrudes into the fixed disk communication passage 70. Then, when the rotating disk 40 further rotates thereafter, the tip 92a of the shear sliding portion 92 protruding into the fixed disk communication passage 70 eventually rides up from within the fixed disk communication passage 70 onto the upper surface 51a of the fixed disk 50. At this time, the shear sliding portion 92 may get caught on the edge of the fixed disk communication passage 70, causing a large stress concentration in the shear sliding portion 92. If a large stress concentration occurs in the shear sliding portion 92, the seal member 81 may become easily worn, and the sealing performance of the seal member 81 may be reduced.

Example 1
Therefore, in this embodiment, the shape of the tip of the seal member 81 on the fixed disk 50 side is devised so that the amount of displacement varies for each part of the seal member 81. Specifically, as shown in Fig. 11, the tip 91a (on the fixed disk 50 side) of the circumferential sliding part 91 of the seal member 81 is formed by a flat part 101 and small R parts 102 with small R shapes formed on both sides of the flat part 101. Also, as shown in Fig. 12, the tip 92a of the shear sliding part 92 of the seal member 81 is formed by a large R part 103 with a large R shape in its entirety. The tip 91a and the tip 92a are examples of the "cross-sectional shape tip" in the present disclosure, and the small R parts 102 are examples of the "R-shaped part" in the present disclosure.

In this way, the tip 91a of the circumferential sliding portion 91 is made less susceptible to displacement than the tip 92a of the shear sliding portion 92. In other words, the Young's modulus of the tip 91a of the circumferential sliding portion 91 is made large, while the Young's modulus of the tip 92a of the shear sliding portion 92 is made small.

Therefore, when the same load is applied to the circumferential sliding portion 91 and the shear sliding portion 92, the displacement δ1 of the tip 91a of the circumferential sliding portion 91 shown in FIG. 13 becomes smaller than the displacement δ2 of the tip 92a of the shear sliding portion 92 shown in FIG. 14.

In this way, by suppressing the displacement amount δ1, the protrusion amount t of the shear sliding portion 92 can be reduced, as shown in FIG. 15.

In other words, as a comparative example, if the tip 91a of the circumferential sliding portion 91 were formed of a large R portion 103 with a large R shape as a whole, like the tip 92a of the shear sliding portion 92, and were made to be easily displaced, the protrusion amount t0 of the shear sliding portion 92 would be large, as shown in FIG. 16. However, in this embodiment, the protrusion amount t can be made smaller than this protrusion amount t0, so the ride-on angle θ of the shear sliding portion 92 can also be made smaller.

The protrusion amount is the amount by which the tip 92a of the shear sliding portion 92 protrudes into the fixed disk communication passage 70. The ride-up angle is the angle at which the tip 92a of the shear sliding portion 92 rides up from within the fixed disk communication passage 70 onto the upper surface 51a of the fixed disk 50.

In addition, the tip 92a of the shear sliding portion 92 has a small Young's modulus to make it easier to displace, so that as shown in FIG. 17, when the tip 92a of the shear sliding portion 92 rides up from within the fixed disk communication passage 70 onto the upper surface 51a of the fixed disk 50, it displaces as shown by the dotted line in FIG. 17, making it possible to more effectively reduce the ride-up angle θ.

In other words, as a comparative example, if the tip 92a of the shear sliding portion 92 were formed of a flat portion 101 and two small R portions 102, like the tip 91a of the circumferential sliding portion 91, and were made less likely to displace, the ride-over angle θ0 would be large, as shown in FIG. 18. However, in this embodiment, the tip 92a of the shear sliding portion 92 is more likely to displace, so the ride-over angle θ can be made smaller more effectively.

According to this embodiment, in the seal member 81, the tip 91a of the circumferential sliding portion 91 is less susceptible to displacement than the tip 92a of the shear sliding portion 92.

In this way, the tip 91a of the circumferential sliding portion 91 is less likely to be displaced. Therefore, when the rotating disk 40 rotates and the tip 92a of the shear sliding portion 92 passes through the fixed disk communication passage 70, the displacement amount δ1 of the tip 91a of the circumferential sliding portion 91 can be suppressed. Therefore, the protrusion amount t of the tip 92a of the shear sliding portion 92, which is released into the fixed disk communication passage 70, into the fixed disk communication passage 70 can be suppressed. Therefore, the ride-up angle θ when the tip 92a of the shear sliding portion 92 rides up from the fixed disk communication passage 70 onto the upper surface 51a of the fixed disk 50 as the rotating disk 40 further rotates can be suppressed, and stress concentration in the seal member 81 can be mitigated.

In addition, since the tip 92a of the shear sliding portion 92 of the seal member 81 is easily displaced, the ride-over angle θ can be more effectively suppressed. As a result, stress concentration in the seal member 81 can be more effectively alleviated.

In this way, stress concentration in the sealing member 81 can be alleviated, thereby preventing the sealing member 81 from breaking or wearing, thereby ensuring the sealing performance of the sealing member 81.

The second to eighth examples will be explained below, focusing on the differences between each example and the other examples.

Second Example
As described above, by providing the flat portion 101 at the tip 91a of the circumferential sliding portion 91, the contact width between the tip 91a of the circumferential sliding portion 91 and the upper surface 51a of the fixed disk 50 is increased. Therefore, there is a risk that the water film will be easily broken at the contact surface between the tip 91a of the circumferential sliding portion 91 and the upper surface 51a of the fixed disk 50.

Here, water curtain cut-off refers to a phenomenon in which, as shown in FIG. 19, when a liquid such as cooling water is flowed as a fluid through the flow path in the flow path switching device 1, the cooling water is difficult to supply between the circumferential sliding portion 91 and the upper surface 51a of the fixed disk 50 behind the circumferential sliding portion 91 in the direction of rotation of the rotating disk 40, making it difficult for a water film to form.

In this embodiment, as shown in FIG. 20, a groove 111 is formed in the flat surface portion 101. This groove 111 is formed along the longitudinal direction of the circumferential sliding portion 91 (i.e., the direction formed across the front side and the depth side of FIG. 20).

As a result, when the fluid is, for example, cooling water (or other liquid), the cooling water flows into the groove portion 111, making it easier to form a water film between the flat portion 101 and the upper surface 51a of the fixed disk 50, thereby reducing the sliding resistance between the tip 91a of the circumferential sliding portion 91 and the upper surface 51a of the fixed disk 50.

(Third Example)
In this embodiment, as shown in Fig. 21, a minute protrusion 112 is provided on the edge of the opening side (the lower side in Fig. 21) of the groove 111. Note that, although two protrusions 112 are provided in the example shown in Fig. 21, only one protrusion 112 may be provided.

In this way, the protrusion 112 improves the ability of the tip 91a of the circumferential sliding portion 91 to follow the upper surface 51a of the fixed disk 50, thereby maintaining the sealing performance at the circumferential sliding portion 91.

(Fourth Example)
In this embodiment, as shown in FIG. 22 , when the sealing member 81 is in a free state (a state in which no load is applied), the tip 92 a of the shear sliding portion 92 is formed to protrude beyond the tip 91 a of the circumferential sliding portion 91 by an amount of protrusion Δ.

This allows a certain level of surface pressure to be applied to the top surface 51a of the fixed disk 50 at the tip 92a of the shear sliding portion 92. This improves the sealing performance at the shear sliding portion 92.

Fifth Example
In this embodiment, as a countermeasure against the water film shortage, as shown in Fig. 23, fine irregularities are provided on the flat surface portion 101 of the tip 91a of the circumferential sliding portion 91. On the other hand, the tip 92a of the shear sliding portion 92 is formed to a mirror finish.

In addition to or instead of providing fine irregularities on the flat surface 101, fine irregularities may be provided on the contact portion between the flat surface 101 and the upper surface 51a of the fixed disk 50, as shown in FIG. 24. In addition to or instead of forming the tip 92a of the shear sliding portion 92 with a mirror finish, the contact portion between the tip 92a of the shear sliding portion 92 with the upper surface 51a of the fixed disk 50 may be formed with a mirror finish, as shown in FIG. 24.

As a result, when the fluid is, for example, cooling water (or other liquid), the cooling water flows through the fine irregularities, making it easier to form a water film between the flat surface portion 101 and the upper surface 51a of the fixed disk 50, thereby reducing the sliding resistance between the tip 91a of the circumferential sliding portion 91 and the upper surface 51a of the fixed disk 50.

In addition, the sliding resistance between the tip 92a of the shear sliding portion 92 and the upper surface 51a of the fixed disk 50 can also be reduced.

(Sixth Example)
25A, in this embodiment, the seal member 81 is integrally molded with the rotating disk 40 and is made of resin. A rubber sheet 113 (sheet-shaped elastic member) that comes into contact with the seal member 81 is provided on the surface of the upper surface 51a of the fixed disk 50 that faces the seal member 81. When the rotating disk 40 rotates, the tip 91a of the circumferential sliding portion 91 and the tip 92a of the shear sliding portion 92 slide on the rubber sheet 113.

As a result, as shown in FIG. 25(a), the outer diameter of the rotating disk 40 can be reduced by molding the sealing member 81 as close as possible to the edge of the rotating disk communication passage 60 and integrally molding the sealing member 81 with the rotating disk 40. As a result, the outer diameter of the housing 11 can also be reduced by the reduction width W shown in FIG. 25(a) and (b), making it possible to miniaturize the flow path switching device 1.

By miniaturizing the flow path switching device 1, the mountability of the flow path switching device 1 can be improved, the weight and materials of the flow path switching device 1 can be reduced, and the rotation torque of the rotating disk 40 can be reduced, so the motor of the drive unit 13 can be made smaller and costs can be reduced. In addition, the sliding distance of the seal member 81 can be shortened, suppressing wear of the seal member 81. In addition, the gap (step) around the communication passages 60 and 70 surrounded by the seal member 81 can be reduced, reducing stagnation of the fluid and reducing pressure loss. In addition, if the outer diameters of the rotating disk 40 and the housing 11 in FIG. 25(a) are made the same as the example in FIG. 25(b), the flow path area of the communication passages 60 and 70 can be expanded.

Also in this embodiment, the tip 91a of the circumferential sliding portion 91 is less likely to be displaced than the tip 92a of the shear sliding portion 92. That is, the tip 91a of the circumferential sliding portion 91 is formed by the flat portion 101 and the small R portion 102, so it is less likely to sink into the rubber sheet 113 and is less likely to be displaced. On the other hand, the tip 92a of the shear sliding portion 92 is formed entirely by the large R portion 103, so it is more likely to sink into the rubber sheet 113 and is more likely to be displaced.

Seventh Example
In this embodiment, that is, as shown in Figures 26 and 27, the width of the flat portion 101 gradually decreases toward the shear sliding region 92. Note that Figure 27 shows, from right to left, cross sections A-A, B-B, C-C, and D-D of Figure 26.

As a result, in the circumferential sliding portion 91, the contact width between the flat portion 101 and the upper surface 51a of the fixed disk 50 gradually decreases toward the shear sliding portion 92. This reduces the sliding resistance between the tip 91a of the circumferential sliding portion 91 and the upper surface 51a of the fixed disk 50.

Eighth Example
In the sixth embodiment, if the rotating disk 40 is stopped for a long time, the seal member 81 will be in contact with the same part of the rubber sheet 113 for a long time with the stress caused by the pressing force of the disk holding spring 82 acting on it, and so there is a risk that, for example, settling will occur in the part of the rubber sheet 113 that contacts the seal member 81 as shown in Fig. 28. If settling occurs in a concentrated manner in a specific part of the rubber sheet 113 in this way, when the rotating disk 40 rotates and the seal member 81 moves, the seal member 81 may not be able to ensure its sealing performance if it slides over the settled part.

Therefore, in this embodiment, the switching stop position of the rotating disk 40 is changed under specified conditions.

Specifically, the control unit 14 performs the control shown in the flowchart in FIG. 29.

As shown in FIG. 29, the control unit 14 acquires the switching valve position tdeg (step S1) and determines whether there is a request to switch the flow path (step S2). Note that the switching valve position tdeg is the rotation angle of the rotating disk 40 as shown in FIG. 6, and indicates the circumferential position of the rotating disk 40.

If there is a request to switch the flow path (step S2: YES), the control unit 14 determines whether the switching of the flow path pattern is from pattern A to pattern B (step S3). Here, pattern A is the first flow path pattern shown in FIG. 6, and pattern B is the second flow path pattern shown in FIG. 7.

If the flow path pattern is switched from pattern A to pattern B (step S3: YES), the control unit 14 adds 1 to the counter value n(i-1) (step S4). In step S4, the formula n(i) = n(i-1) + 1 is calculated. Note that i is a positive integer.

Next, the control unit 14 switches and drives the rotating disk 40 in a counterclockwise direction (step S5), i.e., rotates the rotating disk 40 counterclockwise, and determines whether the counter value n(i) is 1 (step S6).

If the counter value n(i) is 1 (step S6: YES), the control unit 14 determines whether the switching valve position tdeg is equal to or greater than 60deg (step S7).

If the switching valve position tdeg is equal to or greater than 60deg (step S7: YES), the control unit 14 stops the switching drive and completes the switching to pattern B (step S8).

On the other hand, if the switching valve position tdeg is less than 60deg (step S7: NO), the control unit 14 continues to perform the switching drive in the counterclockwise direction (step S9), i.e., continues to rotate the rotating disk 40 in the counterclockwise direction.

Also, in step S6, if the counter value n(i) is not 1 (step S6: NO), the control unit 14 determines whether the counter value n(i) is 2 (step S10).

If the counter value n(i) is 2 (step S10: YES), the control unit 14 determines whether the switching valve position tdeg is equal to or greater than 61deg (step S11).

If the switching valve position tdeg is equal to or greater than 61deg (step S11: YES), the control unit 14 stops the switching drive and completes the switching to pattern B (step S8).

On the other hand, if the switching valve position tdeg is less than 61deg (step S11: NO), the control unit 14 continues to perform counterclockwise switching drive (step S9).

Also, in step S10, if the counter value n(i) is not 2 (step S10: NO), the control unit 14 determines whether the switching valve position tdeg is equal to or greater than 62deg (step S12).

If the switching valve position tdeg is equal to or greater than 62deg (step S12: YES), the control unit 14 sets the counter value n(i) to 0 (step S13), stops the switching drive, and completes the switching to pattern B (step S8).

On the other hand, if the switching valve position tdeg is less than 62deg (step S12: NO), the control unit 14 continues to perform counterclockwise switching drive (step S9).

In addition, in step S3, if the flow path pattern is switched from pattern B to pattern A (step S3: NO), the control unit 14 adds 1 to the counter value m(i-1) (step S14). In step S14, the formula m(i) = m(i-1) + 1 is calculated.

Next, the control unit 14 executes a switching drive for the rotating disk 40 in a clockwise direction (step S15), i.e., rotates the rotating disk 40 in a clockwise direction, and determines whether the counter value m(i) is 1 (step S16).

If the counter value m(i) is 1 (step S16: YES), the control unit 14 determines whether the switching valve position tdeg is less than 0deg (step S17).

If the switching valve position tdeg is less than 0deg (step S17: YES), the control unit 14 stops the switching drive and completes the switching to pattern A (step S18).

On the other hand, if the switching valve position tdeg is equal to or greater than 0deg (step S17: NO), the control unit 14 continues to perform the switching drive in the clockwise direction (step S19), i.e., continues to rotate the rotating disk 40 in the clockwise direction.

Also, in step S16, if the counter value m(i) is not 1 (step S16: NO), the control unit 14 determines whether the counter value m(i) is 2 (step S20).

If the counter value m(i) is 2 (step S20: YES), the control unit 14 determines whether the switching valve position tdeg is less than -1deg (step S21).

If the switching valve position tdeg is less than -1deg (step S21: YES), the control unit 14 stops the switching drive and completes the switching to pattern A (step S18).

On the other hand, if the switching valve position tdeg is -1deg or greater (step S21: NO), the control unit 14 continues to perform the switching drive in the clockwise direction (step S19).

Also, in step S20, if the counter value m(i) is not 2 (step S20: NO), the control unit 14 determines whether the switching valve position tdeg is less than -2deg (step S22).

If the switching valve position tdeg is less than -2deg (step S22: YES), the control unit 14 sets the counter value m(i) to 0 (step S23), stops the switching drive, and completes the switching to pattern A (step S18).

On the other hand, if the switching valve position tdeg is -2deg or greater (step S22: NO), the control unit 14 continues to perform the switching drive in the clockwise direction (step S19).

As described above, according to this embodiment, the switching stop position of the rotating disk 40 is changed under a predetermined condition. Here, "under a predetermined condition" refers to, for example, a condition in which switching is performed from pattern A to pattern B, then switching from pattern B to pattern A, and then switching from pattern A to pattern B again, and a condition in which switching is performed from pattern B to pattern A, then switching from pattern A to pattern B, and then switching from pattern B to pattern A again. In this way, the switching stop position of the rotating disk 40 is changed each time the same flow path pattern is switched.

This prevents the rubber sheet 113 from becoming worn due to pressure from the sealing member 81, even if the rotating disk 40 is stopped for a long period of time.

The above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure.

For example, the contents of the present disclosure above can also be applied to a slide valve that switches flow path patterns by sliding the slide valve in the axial direction of the drive shaft using the drive shaft to change the combination of communication between the flow path port of the housing and the communication passage of the slide valve.

1 Flow path switching device 11 Housing 12 Valve body portion 14 Control portion 20 Inflow flow path 21 First inflow flow path 22 Second inflow flow path 23 Third inflow flow path 30 Outflow flow path 31 First outflow flow path 32 Second outflow flow path 33 Third outflow flow path 40 Rotating disk 41 Circular disk portion 50 Fixed disk 51 Circular disk portion 51a Upper surface 60 Rotating disk communication passage 61 First rotating disk communication passage 62 Second rotating disk communication passage 63 Third rotating disk communication passage 70 Fixed disk communication passage 71 First fixed disk communication passage 72 Second fixed disk communication passage 73 Third fixed disk communication passage 81 Seal member 91 Circumferential sliding portion 91a Tip 92 Shear sliding portion 92a Tip 101 Planar portion 102 Small R portion 103 Large R portion 111 Groove portion 112 Convex portion 113 Rubber sheet δ1 Displacement amount δ2 Displacement amount t Protrusion amount θ Ride-on angle

Claims (9)

A fixing member;
A drive member,
a flow path switching device for switching a combination of ports of the fixed member and communication paths of the drive member by being driven by the drive member, the flow path switching device comprising:
the drive member includes a seal member provided around the communication passage of the drive member so as to protrude toward the fixed member and for sealing between the drive member and the fixed member;
The sealing member is
A first portion formed along a driving direction of the driving member;
a second portion connecting two of the first portions arranged in a direction perpendicular to the driving direction of the driving member;
It is formed by
A tip end of the cross-sectional shape of the first portion is less likely to be displaced than a tip end of the cross-sectional shape of the second portion;
A flow path switching device characterized by the above. 2. The flow path switching device according to claim 1,
A flat portion is formed at a tip of the cross-sectional shape of the first portion,
The cross-sectional shape of the tip of the second portion is entirely formed in an R shape;
A flow path switching device characterized by the above. In the flow path switching device of claim 2,
A groove is formed in the flat surface.
A flow path switching device characterized by the above. In the flow path switching device of claim 3,
Providing a convex portion on an edge of the opening side of the groove portion;
A flow path switching device characterized by the above. In the flow path switching device of claim 2,
providing fine irregularities on the flat surface and/or on a contact portion of the fixing member with the flat surface;
A flow path switching device characterized by the above. 6. The flow path switching device according to claim 2,
The width of the planar portion gradually decreases toward the second region.
A flow path switching device characterized by the above. 6. The flow path switching device according to claim 1,
When the seal member is in a free state, a tip end of the cross-sectional shape of the second portion is formed to protrude further than a tip end of the cross-sectional shape of the first portion;
A flow path switching device characterized by the above. 6. The flow path switching device according to claim 1,
The seal member is integrally formed with the drive member,
an elastic member that comes into contact with the seal member is provided on a surface of the fixing member that faces the seal member;
A flow path switching device characterized by the above. The flow path switching device according to claim 8,
Changing the stop position of the drive member under a predetermined condition;
A flow path switching device characterized by the above.

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