WO2025205356A1 - Valve device - Google Patents

Abstract

This valve device is provided with: a housing (10) that forms a fluid channel (F); a fixed disk (20) which is disposed inside the housing and in which is formed at least one channel hole (23) through which a fluid flows; a drive unit (40) that outputs torque; a shaft (50) that rotates around a shaft axis (CL) due to the torque output by the drive unit; and a drive disk (30) that increases and decreases the aperture of the channel hole as the shaft rotates and that slides against the fixed disk so as to rotate around the shaft axis. The fixed disk has a seal surface (21) that faces the drive disk on one side in a direction in which the shaft axis extends. The drive disk has a sliding surface (31) that slides against the seal surface on the other side in the direction in which the shaft axis extends. A central portion of at least one of the seal surface and the sliding surface of the fixed disk and the drive disk has a convex shape, formed so as to protrude toward the other surface.

Description

Valve equipment CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on Japanese Patent Application No. 2024-49898, filed on March 26, 2024, the contents of which are incorporated herein by reference.

This disclosure relates to a valve device.

Conventionally, a valve device has been known that includes a housing that forms a fluid passage, a fixed disk that has a flow passage hole formed therein through which the fluid passes, a drive disk that increases or decreases the opening of the flow passage hole, and a drive unit that outputs a rotational force to rotate the drive disk (see, for example, Patent Document 1). In this valve device, the housing is formed with one inlet that directs fluid into the fluid passage, and two outlets that communicate with the flow passage hole and allow the fluid to flow out of the fluid passage. The flow passage hole in the fixed disk is opened or closed depending on the rotational position of the drive disk, which is positioned by the rotational force of the drive unit, thereby switching the outlet that communicates with the inlet.

International Publication No. 2014/072376

When the drive disk rotates due to the rotational force of the drive unit, it must be rotated while pressed against the fixed disk in order to prevent fluid from leaking between the drive disk and the fixed disk. This generates frictional force between the drive disk and the fixed disk. Therefore, the drive unit must increase the maximum rotational force it can output compared to when no friction occurs between the drive disk and the fixed disk.

Furthermore, as the contact area between the drive disk and fixed disk increases due to the increase in size of the drive disk and fixed disk, the frictional force generated between the drive disk and fixed disk tends to increase. For this reason, the larger the drive disk and fixed disk, the greater the maximum rotational force that the drive unit can output.

However, if the maximum value of the rotational force that the drive unit can output increases, there is a risk that the drive unit and the valve device will also increase in size. For this reason, it is desirable to suppress the maximum value of the rotational force that the drive unit can output.

In consideration of the above, the present disclosure aims to provide a valve device that can suppress the maximum value of the rotational force that can be output by the drive unit.

According to one aspect of the present disclosure,
The valve device
a housing having a fluid passage formed therein for allowing a fluid to flow therethrough;
a fixed disk disposed inside the housing and having at least one flow path hole formed therein through which a fluid flows;
a drive unit that outputs a rotational force;
a shaft that rotates around its axis by a rotational force output by a drive unit;
a drive disk that increases or decreases the opening of the flow path hole in accordance with the rotation of the shaft, and that slides against the fixed disk and rotates around the shaft axis;
the fixed disk has a seal surface facing the drive disk on one side in the direction in which the shaft axis extends,
the drive disk has a sliding surface that slides against the seal surface on the other side in the direction in which the shaft axis extends,
The fixed disk and the drive disk have a convex shape formed such that the central portion of at least one of the seal surface and the sliding surface protrudes toward the other surface compared to the remaining portion.

This reduces the frictional force that occurs in areas away from the center of each surface, which tends to be large if the center portions of both the sealing surface and the sliding surface do not protrude toward the other surface. Therefore, compared to when the center portions of both the sealing surface and the sliding surface do not protrude toward the other surface, the maximum value of the rotational force that can be output by the drive unit can be reduced.

1 is a perspective view of the appearance of a valve device according to an embodiment of the present invention; FIG. 2 is a side view of the valve device according to the embodiment. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. 3 is a view of the drive disk according to the embodiment as viewed from the side opposite to the sliding surface side. FIG. 5A and 5B are diagrams illustrating a lever according to the embodiment. FIG. 2 is a diagram showing the appearance of a fixed disk before surface treatment is performed. FIG. 10 is a diagram showing the appearance of the fixed disk after surface treatment. 10A and 10B are diagrams illustrating the shape of a fixed disc when not pressed by a compression spring. 10A and 10B are diagrams illustrating the shapes of a fixed disk and a drive disk when pressed by a compression spring. 10A and 10B are diagrams illustrating the shapes of the fixed disc and the drive disc when further pressed by the compression spring. FIG. 10 is a diagram showing a modified example of the drive disk. FIG. 10 is a diagram showing a modified example of the fixed disk. FIG. 10 is a diagram showing a modified example of the drive disk. 10A and 10B are diagrams showing modified examples of the fixed disk and the drive disk; 10A and 10B are diagrams showing modified examples of the fixed disk and the drive disk; FIG. 10 is a diagram showing a modified example of the drive disk.

One embodiment of the present disclosure will be described with reference to Figures 1 to 10. The valve device 1 of this embodiment is applied to a fluid circulation system in which a fluid (in this example, coolant) circulates to regulate the temperature inside the cabin and battery of an electric or hybrid vehicle, for example. The fluid circulation system is a system that circulates coolant through the power source for driving the vehicle, the radiator, the heater core for cabin air conditioning, the battery, etc. As the coolant, for example, LLC (Long Life Coolant) containing ethylene glycol is used. The valve device 1 switches the flow path of the coolant flowing within the fluid circulation system or adjusts the flow rate. In this embodiment, the valve device 1 is configured as a four-way valve, for example.

As shown in Figures 1 and 2, the valve device 1 has a housing 10 that forms a fluid passage F through which fluid flows. The housing 10 has one inlet port that allows fluid to flow into the fluid passage F from outside the valve device 1, and three outlet ports that allow the fluid that has flowed into the fluid passage F to flow out to the outside of the valve device 1. Hereinafter, as shown in Figure 1 and other figures, the two fluid ports that allow fluid to flow into the fluid passage F will be referred to as first inlet portions 10a, and the three outlet ports that allow fluid to flow out of the fluid passage F will be referred to as first outlet portion 10b, second outlet portion 10c, and third outlet portion 10d.

First, the configuration of the valve device 1 of this embodiment will be described. As shown in Figures 1 to 3, the valve device 1 of this embodiment includes a fixed disc 20, a drive disc 30, a drive unit 40, a shaft 50, a lever 60, a first torsion spring 70, a second torsion spring 80, and a compression spring 90. The valve device 1 accommodates the fixed disc 20, drive disc 30, shaft 50, lever 60, first torsion spring 70, second torsion spring 80, and compression spring 90 within a housing 10. The valve device 1 also includes a drive unit 40 located outside the housing 10. The valve device 1 of this embodiment is configured as a disc valve in which the drive unit 40 rotates the drive disc 30 integrally with the shaft 50, thereby switching the flow path of the cooling water flowing through the fluid circulation system. Note that the drive unit 40 has been omitted from Figure 3 for clarity.

In this embodiment, as shown in Figure 3 and other figures, the direction along the shaft axis CL of the shaft 50 is referred to as the axial direction DRa, the direction to one side of the axial direction DRa is referred to as the downward direction DRa1, and the direction opposite the downward direction DRa1 is referred to as the upward direction DRa2. Furthermore, various configurations will be described using the direction around the shaft axis CL as the circumferential direction DRc and the direction perpendicular to the axial direction DRa and extending radially from the shaft axis CL as the radial direction DRr. The circumferential direction DRc is the direction of rotation of the shaft 50 and drive disk 30, which are rotated by the rotational force supplied from the drive unit 40. Note that the directions shown in Figure 2 and other figures are merely examples and do not limit the installation state of the valve device 1 of the present disclosure.

The housing 10 is a non-rotating member. The housing 10 is formed, for example, from a resin material. Specifically, the housing 10 has a cylindrical main body 11 with a bottom, and a main body cover 12 that closes the open side of the main body 11. In this embodiment, the main body 11 and main body cover 12 are molded, for example, by injection molding, in which a resin material is poured into a mold and hardened into the desired shape.

The main body 11 has a bottom wall 13 that forms the bottom surface and a cylindrical side wall 14 that surrounds the shaft axis CL in the circumferential direction DRc. The bottom wall 13 and side wall 14, together with the main body cover 12, form a fluid passage F. The bottom wall 13 and side wall 14 are molded together as a single unit.

The main body 11 has a first inlet 10a connected to the outer peripheral surface of the side wall 14. The main body 11 also has a first outlet 10b and a second outlet 10c connected to the outer peripheral surface of the bottom wall 13, and a third outlet 10d connected to the underside of the bottom wall 13 in the downward direction DRa1.

The first inlet portion 10a, first outlet portion 10b, second outlet portion 10c, and third outlet portion 10d are made of tubular members formed to allow fluid to flow through the inside. The first inlet portion 10a, first outlet portion 10b, and second outlet portion 10c are formed to protrude from the housing 10 along the radial direction DRr. The third outlet portion 10d is formed to protrude from the housing 10 along the axial direction DRa.

The side wall portion 14 has a cylindrical shape that surrounds the upper fluid passage Fu in the circumferential direction DRc, which is located on the upper direction DRa2 side of the fixed disk 20 in the fluid passage F, and extends along the axial direction DRa. The side wall portion 14 is formed so that its axis is coaxial with the shaft axis CL. An engagement groove (not shown) is formed on the inner peripheral surface of the side wall portion 14 to receive an engagement protrusion (not shown) of the fixed disk 20. The opening side of the side wall portion 14 is closed by the main body cover portion 12.

The body cover part 12 is a lid that closes the opening side of the body part 11. The body cover part 12 is attached to the body part 11 by fitting it inside the body part 11 from the opening side of the body part 11. In other words, the upper fluid passage Fu formed by the inner surface of the side wall part 14 is closed by the body cover part 12. The body cover part 12 is attached to the body part 11 together with the drive part 40 by, for example, tapping screws S.

An O-ring 162 that closes the gap between the main body 11 and the main body cover 12 is disposed between the inner circumferential surface of the side wall 14 and the outer circumferential surface of the main body cover 12. The O-ring 162 is made of, for example, urethane rubber, which is an annular elastic body, and is configured to be compressed and elastically deformable when sandwiched between the main body 11 and the main body cover 12.

The bottom wall portion 13 is the portion on which the fixed disk 20 is mounted and which supports the downward DRa1 side of the axial center portion 51 of the shaft 50 (described below). The bottom wall portion 13 also forms the fluid passage F which guides the fluid flowing in from the first inlet portion 10a to the first outlet portion 10b, the second outlet portion 10c, and the third outlet portion 10d.

As shown in FIG. 3, the bottom wall portion 13 has a mounting surface 131 on the upward DRa2 side for placing the fixed disk 20. The bottom wall portion 13 also has a bearing hole 132 that supports the axial center portion 51, and a lower fluid passage Fd on the downward DRa1 side of the fixed disk 20 in the fluid passage F. The downward DRa1 side of the axial center portion 51 is fitted into the bearing hole 132. The bearing hole 132 rotatably supports the axial center portion 51.

The lower fluid passage Fd is divided into three sections by the bottom wall 13, and is connected to one of the first outlet 10b, second outlet 10c, and third outlet 10d. Although not shown, the bottom wall 13 is provided with a plate-shaped partition that divides the lower fluid passage Fd into a passage that connects to the first outlet 10b, a passage that connects to the second outlet 10c, and a passage that connects to the third outlet 10d. This partition is arranged to cross the lower fluid passage Fd in the radial direction DRr, and divides the lower fluid passage Fd into three sections in the circumferential direction DRc.

The mounting surface 131 is formed to extend flatly in the radial direction DRr and the circumferential direction DRc. A gasket groove 133 is formed in the mounting surface 131 for accommodating a gasket 15 that seals the gap between the fixed disk 20 and the mounting surface 131. The gasket 15 is made of, for example, an elastically deformable rubber material, and is formed in a shape that corresponds to the lower fluid passage Fd.

The fixed disk 20 is a sealing member that seals the gap between the bottom wall portion 13 and the drive disk 30. The fixed disk 20 is made of a thin, approximately disk-shaped member with its thickness direction aligned with the axial direction DRa, and its outer diameter is slightly smaller than the inner diameter of the side wall portion 14. The fixed disk 20 is also arranged so that its axis is coaxial with the shaft axis CL. The fixed disk 20 is also arranged within the housing 10, pressed by the drive disk 30, which is biased by the compression spring 90.

The fixed disk 20 has a sealing surface 21 that contacts the drive disk 30 and a support surface 22 that contacts the installation surface 131. The sealing surface 21 is an opposing surface that faces the sliding surface 31 of the drive disk 30, which will be described later, and comes into contact with said sliding surface 31.

As shown in FIG. 3, the fixed disk 20 has three flow path holes 23 formed therein that communicate with the lower fluid passage Fd, allowing fluid to pass through these flow path holes 23. The fixed disk 20 also has a fixed disk hole 24 formed in its approximate center, through which the shaft 50 is inserted, and a mating protrusion (not shown) formed on its outer circumferential surface. The mating protrusion fits into a mating groove (not shown) formed on the inner circumferential surface of the side wall portion 14, thereby restricting rotation of the fixed disk 20 in the circumferential direction DRc.

The fixed disk 20 is made of a material that has a smaller coefficient of linear expansion, superior wear resistance, and a smaller coefficient of friction than the material that makes up the housing 10. For example, the fixed disk 20 is made of a high-hardness material that is harder than the housing 10 and the drive disk 30. The fixed disk 20 is made of a metal that is harder than resin (for example, SUS, i.e., Steel Use Stainless Steel).

The sealing surface 21 and the support surface 22 are formed to extend in a planar shape along the radial direction DRr and the circumferential direction DRc. The sealing surface 21 and the support surface 22 are approximately perpendicular to the axial direction DRa and are approximately parallel to each other in the radial direction DRr.

The three flow path holes 23 are formed at positions away from the fixed disk hole 24 so as not to overlap with the fixed disk hole 24. The flow path holes 23 are formed, for example, in a sector shape (i.e., fan shape). The flow path holes 23 are communication paths that connect the upper fluid path Fu and the lower fluid path Fd.

The drive disc 30 is a valve element that increases or decreases the opening of the flow path hole 23 in the fixed disc 20 by rotating about the shaft axis CL as the shaft 50 rotates. As shown in Figures 3 and 4, the drive disc 30 is composed of a substantially disk-shaped member with its thickness direction aligned with the axial direction DRa, and its outer diameter is smaller than the inner diameter of the side wall portion 14. The drive disc 30 is positioned so that its rotation axis is coaxial with the shaft axis CL. The drive disc 30 is also positioned within the housing 10, biased by a compression spring 90.

As shown in Figure 3, the drive disk 30 faces the seal surface 21 of the fixed disk 20 and has a sliding surface 31 that slides against the seal surface 21. Furthermore, as shown in Figure 4, the drive disk 30 has a drive disk hole 32 formed in the approximate center, through which the shaft 50 is inserted, and two press-fit grooves 33 into which the levers 60 (described below) are press-fit. The press-fit grooves 33 are formed at a position away from the drive disk hole 32 of the drive disk 30 so as not to overlap with the drive disk hole 32. The press-fit grooves 33 are formed at a position closer to the outer periphery than the central axis of the drive disk 30.

Furthermore, the drive disk 30 is formed with one through-hole 34 that penetrates the drive disk 30 in the axial direction DRa, allowing fluid to pass through the through-hole 34. The through-hole 34 is formed in a position that allows it to overlap with each of the three flow path holes 23 of the fixed disk 20 in the axial direction DRa when the drive disk 30 is rotated around the shaft axis CL.

The drive disk 30 is made of a material that has a lower coefficient of linear expansion, superior wear resistance, and a lower coefficient of friction than the material that makes up the housing 10. For example, the drive disk 30 is made of a high-hardness resin that is harder than the housing 10.

The sliding surface 31 is the surface of the drive disk 30 on the downward direction DRa1 side, facing the seal surface 21. The sliding surface 31 slides against the seal surface 21 of the fixed disk 20 when the drive disk 30 rotates in conjunction with the rotation of the shaft 50. The sliding surface 31 is formed to extend flatly in the radial direction DRr and the circumferential direction DRc. The sliding surface 31 is approximately perpendicular to the axial direction DRa and approximately parallel to the radial direction DRr.

Returning to Figure 2, the drive unit 40 is provided on the upward DRa2 side of the main body cover unit 12. The drive unit 40 is a device for outputting rotational force to rotate the shaft 50. The drive unit 40 has the shaft 50, a motor (not shown) that serves as a drive source for rotating the shaft 50, and a gear unit (not shown) that transmits the motor output to the shaft 50. The motor can be, for example, a servo motor, stepping motor, or brushless motor. The gear unit can be, for example, a gear mechanism including a helical gear or a spur gear.

The shaft 50 is a rotating shaft that rotates around the shaft axis CL by the rotational force output by the drive unit 40. As shown in FIG. 3, the shaft 50 is rotatably supported on both sides in the axial direction DRa by the housing 10. As a specific example, the downward DRa1 side of the shaft 50 is rotatably supported by a bearing (not shown) provided in the bearing hole 132, and the upward DRa2 side of the shaft 50 is rotatably supported by the bearing portion 41 provided in the main body cover portion 12. These bearings can be plain bearings, ball bearings, etc.

The shaft 50 includes a metal axial center portion 51 and a resin holder portion 52 connected to the axial center portion 51. The axial center portion 51 and the holder portion 52 are connected to each other so that they can rotate together. The axial center portion 51 and the holder portion 52 are insert-molded products that are molded together by insert molding.

The axial center portion 51 includes the shaft axis CL of the shaft 50 and extends along the axial direction DRa. To ensure straightness, the axial center portion 51 is made of a metal rod member. The upward DRa2 side of the axial center portion 51 is connected to the holder portion 52. The axial center portion 51 then penetrates the fixed disk 20 and the drive disk 30.

The holder portion 52 has a cylindrical shape with a bottom that opens downward in the direction DRa1. The axial center portion 51 of the holder portion 52 is connected to the inside of the tip portion on the upward direction DRa2 side. The tip portion of the holder portion 52 that protrudes outside the main body cover portion 12 is connected to the drive unit 40. This transmits the rotational force output by the drive unit 40 to the shaft 50. The rotational force output by the drive unit 40 is transmitted to the drive disk 30 via the shaft 50, lever 60, and second torsion spring 80. The shaft 50 is connected to the drive disk 30 via the lever 60 and second torsion spring 80.

The lever 60 is a connecting member that connects the drive disk 30 to the shaft 50. The lever 60 is fixed to the drive disk 30 and connects the drive disk 30 and shaft 50 so that they can rotate together while the drive disk 30 is displaceable in the axial direction DRa of the shaft 50. As shown in FIG. 5, the lever 60 has two press-fit portions 61 formed on the surface facing the drive disk 30. The two press-fit portions 61 protrude toward the drive disk 30 so that they can be press-fit into two press-fit grooves 33 formed in the drive disk 30, respectively. The lever 60 is fixed to the drive disk 30 by press-fitting the press-fit portions 61 into the press-fit grooves 33 of the drive disk 30. In this way, the press-fit grooves 33 into which the press-fit portions 61 of the lever 60 are press-fitted to connect the lever 60 and the drive disk 30 function as a connecting portion.

As shown in FIG. 3, the first torsion spring 70 is a spring that biases the shaft 50 in the circumferential direction DRc relative to the housing 10. The first torsion spring 70 can be, for example, a torsion coil spring that is elastically deformable in the circumferential direction DRc. The first torsion spring 70 is disposed between the housing 10 and the shaft 50. The first torsion spring 70 is used in a state in which it is twisted and elastically deformed in the circumferential direction DRc. The first torsion spring 70 is disposed between the housing 10 and the shaft 50 in a state in which it is compressed in the circumferential direction DRc, with one end of the first torsion spring 70 in contact with the housing 10 and the other end of the first torsion spring in the circumferential direction DRc in contact with the holder portion 52 of the shaft 50.

The biasing force of the first torsion spring 70 is transmitted as rotational force from the gear portion of the drive unit 40 to the motor via the shaft 50. Therefore, by placing the first torsion spring 70 between the housing 10 and the shaft 50, rattle in the circumferential direction DRc between the drive unit 40 and the shaft 50 is suppressed.

The second torsion spring 80 is a spring that biases the shaft 50 in the circumferential direction DRc relative to the housing 10. The second torsion spring 80 can be, for example, a torsion coil spring that is elastically deformable in the circumferential direction DRc. The second torsion spring 80 is disposed between the lever 60 and the shaft 50. The second torsion spring 80 is used in a state in which it is twisted and elastically deformed in the circumferential direction DRc. The second torsion spring 80 is disposed between the lever 60 and the shaft 50 in a state in which it is compressed in the circumferential direction DRc, with one end of the second torsion spring 80 in contact with the lever 60 and the other end of the second torsion spring in contact with the holder portion 52 of the shaft 50.

As a result, the second torsion spring 80, through its own elastic deformation, generates a biasing force that biases the drive disc 30 to one side in the circumferential direction DRc. When the rotational force generated by the drive unit 40 is transmitted to the shaft 50, the rotational force is transmitted to the drive disc 30 via the second torsion spring 80 and the lever 60. As the shaft 50 rotates, the drive disc 30 rotates integrally with the shaft 50 around the shaft axis CL.

The compression spring 90 is a biasing part that biases the drive disk 30 against the fixed disk 20. The compression spring 90 can be, for example, a compression coil spring that is elastically deformable in the axial direction DRa of the shaft 50. The compression spring 90 is disposed inside the housing 10 in a compressed state in the axial direction DRa, with its end on the downward DRa1 side contacting the lever 60 and its end on the upward DRa2 side contacting the holder part 52 of the shaft 50. The compression spring 90 is not fixed to at least one of the drive disk 30 and the shaft 50 so that it does not function as the first torsion spring 70 or the second torsion spring 80.

The compression spring 90 presses the drive disk 30 against the fixed disk 20, maintaining contact between the seal surface 21 of the fixed disk 20 and the sliding surface 31 of the drive disk 30. This contact state is a state in which the seal surface 21 of the fixed disk 20 and the sliding surface 31 of the drive disk 30 are in surface contact. In other words, the valve device 1 can maintain the drive disk 30 in contact with the fixed disk 20.

The compression spring 90 is positioned to surround the shaft axis CL of the shaft 50. In other words, the shaft 50 is positioned inside the compression spring 90. This prevents the load of the compression spring 90 on the drive disk 30 from being biased in the circumferential direction DRc of the shaft 50, making it easier to maintain contact between the seal surface 21 and the sliding surface 31.

The compression spring 90 is also positioned inside the holder portion 52 and is capable of pressing the central periphery of the surface of the lever 60 on the upward DRa2 side in the downward DRa1 direction.

Next, the operation of the valve device 1 of this embodiment will be described. Fluid flows into the fluid passage F of the valve device 1 from the first inlet port 10a. The fluid that flows into the fluid passage F flows out from one of the first outlet port 10b, second outlet port 10c, and third outlet port 10d, depending on the rotational position of the drive disk 30.

Specifically, when the through hole 34 is positioned at a rotational position where it communicates with one of the three flow path holes 23, the fluid flows out of one of the first outlet portion 10b, second outlet portion 10c, and third outlet portion 10d via the lower fluid passage Fd that communicates with that flow path hole 23. In other words, the outlet portion from which the fluid flows out, among the first outlet portion 10b, second outlet portion 10c, and third outlet portion 10d, is determined by the rotational position of the drive disk 30. The drive disk 30 rotates due to the rotational force output by the drive unit 40, and its rotational position is maintained by that rotational force.

When the drive disk 30 is rotated by the rotational force of the drive unit 40, it is desirable to rotate the sliding surface 31 while pressing it against the seal surface 21 in order to prevent fluid from leaking from the gap between the seal surface 21 and the sliding surface 31. For this reason, the valve device 1 of this embodiment is provided with a compression spring 90 that presses the sliding surface 31 against the seal surface 21, maintaining contact between the seal surface 21 and the sliding surface 31. When the drive disk 30 is rotated by the rotational force of the drive unit 40, the seal surface 21 and the sliding surface 31 slide against each other.

As a result, when the drive disk 30 rotates due to the rotational force of the drive unit 40, frictional force is generated between the seal surface 21 and the sliding surface 31. Therefore, the valve device 1 needs to employ a drive unit 40 that can output a larger maximum rotational force than when no frictional force is generated between the seal surface 21 and the sliding surface 31.

Furthermore, the larger the outer diameters of the fixed disk 20 and the drive disk 30, the larger the contact area between the seal surface 21 and the sliding surface 31. In such cases, the frictional force generated between the seal surface 21 and the sliding surface 31 tends to increase. For this reason, the larger the outer diameters of the fixed disk 20 and the drive disk 30, the more necessary it is to use a drive unit 40 with a large maximum output rotational force.

However, a drive unit 40 with a large maximum value of the torque that can be output can lead to an increase in the size of the drive unit 40 and the size of the valve device 1. For this reason, it is desirable to suppress the frictional force that occurs between the seal surface 21 and the sliding surface 31, and to suppress the maximum value of the torque that can be output by the drive unit 40.

For this reason, in the valve device 1 of this embodiment, in order to reduce the frictional force generated between the seal surface 21 and the sliding surface 31, a frictional force reduction structure is provided on at least one of the fixed disk 20 and the drive disk 30. Specifically, in this embodiment, the fixed disk 20 has a structure in which the central portion of the seal surface 21 has a convex shape that protrudes more toward the sliding surface 31 than the other portions. This makes it possible to reduce the frictional force generated between the seal surface 21 and the sliding surface 31 when the drive disk 30 rotates due to the rotational force of the drive unit 40.

The specific shape of the fixed disk 20 will be described with reference to Figures 6 and 7. As described above, the fixed disk 20 of this embodiment is formed from a thin, approximately disk-shaped member. The fixed disk 20 has a warped shape due to internal stress generated in the fixed disk 20 by applying a surface treatment to the protruding surface, i.e., the sealing surface 21 facing the sliding surface 31 of the drive disk 30. This allows the shape of the fixed disk 20 to be made spherical, with the central portion of the sealing surface 21 protruding more toward the sliding surface 31 than the other portions. Furthermore, the sealing surface 21 of the fixed disk 20, which is surface-treated, is covered with a coating material 25.

Here, Figure 6 shows the appearance of the fixed disk 20 before surface treatment, and Figure 7 shows the appearance of the fixed disk 20 after surface treatment. As shown in Figure 6, the fixed disk 20 before surface treatment is thin and has a planar shape with the sealing surface 21 and support surface 22 parallel to each other. In other words, before being placed in the valve device 1, the fixed disk 20 has the support surface 22 positioned on one side of the axial direction DRa when the fixed disk 20 is installed in the valve device 1 and the sealing surface 21 positioned on the other side of the axial direction DRa, both of which are approximately parallel to each other.

In contrast, as shown in Figure 7, after surface treatment, the fixed disc 20 has a curved, warped shape at the sealing surface 21 and support surface 22 due to the surface treatment in which the sealing surface 21 is covered with a coating material 25. In other words, when the fixed disc 20 is installed in the valve device 1, the support surface 22 located on one side of the axial direction DRa and the sealing surface 21 located on the other side each protrude toward the sliding surface 31. The sealing surface 21 protrudes gradually toward the sliding surface 31 from the outer periphery toward the center, with the central portion being the largest in warp.

The coating material 25 used in the surface treatment to give the central portion of the seal surface 21 a convex shape facing the sliding surface 31 can have a smaller Young's modulus than the fixed disk 20 that constitutes the seal surface 21 covered by the coating material 25. Various surface treatment methods can be used to give the central portion of the seal surface 21 a convex shape facing the sliding surface 31. For example, a DLC coating (i.e., diamond-like carbon coating) can be used to cover the seal surface 21 with a thin film of coating material 25 whose main component is carbon. DLC coating can be performed using methods such as ion plating, PVD (i.e., physical vapor deposition), and CVD (i.e., chemical vapor deposition).

As a result, the fixed disk 20 after surface treatment can be warped by several microns to several tens of microns compared to before surface treatment. Note that, unlike the fixed disk 20, the drive disk 30 of this embodiment has not been surface treated to give the drive disk 30 a warped shape. Therefore, before the drive disk 30 is placed in the valve device 1, the sliding surface 31 of the drive disk 30 is formed in a flat shape extending along the radial direction DRr. Furthermore, in Figure 7 and Figure 8 (described below), the magnitude of the warp is shown larger than the actual warp to make it easier to understand that the fixed disk 20 has a warped shape.

The fixed disc 20 formed in this manner has its sliding surface 31 pressed against the seal surface 21 by the drive disc 30, which is pressed by the compression spring 90. As the seal surface 21 is pressed against the sliding surface 31, the fixed disc 20 is deformed and is positioned within the valve device 1 with almost the entire seal surface 21 in contact with the sliding surface 31.

The shape of the fixed disc 20, which is deformed when placed within the valve device 1, will be explained with reference to Figures 8 to 10. Note that in Figures 8 to 10, the housing 10, shaft 50, first torsion spring 70, second torsion spring 80, and coating material 25 are omitted to make the shape of the fixed disc 20 easier to understand.

Figure 8 shows the drive disc 30 not yet pressed by the compression spring 90. When the fixed disc 20 is placed inside the valve device 1, the drive disc 30 with the lever 60 attached is placed on the upward DRa2 side of the fixed disc 20 with the axial center portion 51 of the shaft 50 inserted into the fixed disc hole 24.

In the state shown in Figure 8, the fixed disk 20 has a sealing surface 21 formed to protrude upward in the DRa2 direction, and only the central portion of the sealing surface 21 contacts the sliding surface 31, while the portion away from the central portion in the radial direction DRr does not contact the sliding surface 31. Furthermore, the central portion of the support surface 22 of the fixed disk 20 does not contact the installation surface 131, and only the portion near the outer circumferential surface away from the central portion in the radial direction DRr is supported by the installation surface 131.

As shown in Figure 9, when the lever 60 and drive disk 30 are pushed by the compression spring 90 from the upward direction DRa2 toward the downward direction DRa1, the seal surface 21 of the fixed disk 20 is pressed against the sliding surface 31 of the drive disk 30. This causes the fixed disk 20 to deform, and substantially the entire support surface 22 is supported by the installation surface 131.

Then, as the lever 60 and drive disk 30 are further pressed by the compression spring 90, the seal surface 21 of the fixed disk 20 is further pressed against the sliding surface 31 of the drive disk 30. As a result, the sliding surface 31 of the drive disk 30 assumes a shape that follows the shape of the seal surface 21, which has a spherical shape with a protruding central portion, as shown in FIG. 10. In other words, the sliding surface 31 assumes a spherical shape with a curvature approximately equal to that of the seal surface 21. This maintains contact between the seal surface 21 and the sliding surface 31.

As described above, the lever 60 of this embodiment is connected to the drive disk 30 by having the press-fit portion 61 press-fit into the press-fit groove 33 of the drive disk 30. The press-fit groove 33 is formed at a position closer to the outer peripheral surface than the central axis of the drive disk 30. Therefore, the biasing force of the compression spring 90 pressing against the central portion of the surface of the lever 60 facing upward in the DRa2 direction is transmitted via the lever 60 to the central portion of the drive disk 30 as well as to the portion of the drive disk 30 where the press-fit groove 33 is formed, which is closer to the outer peripheral surface. In other words, the lever 60 presses against the central portion and a portion of the drive disk 30 close to the outer peripheral surface with the biasing force received from the compression spring 90. Therefore, when the sliding surface 31 of the drive disk 30 presses against the seal surface 21 of the fixed disk 20, the biasing force of the compression spring 90 is transmitted to the central portion of the seal surface 21 as well as to a portion close to the outer peripheral surface.

As a result, the shape of the sliding surface 31 tends to follow the shape of the sealing surface 21. This makes it easier to maintain contact between the sealing surface 21 and the sliding surface 31.

Next, we will explain the frictional force that occurs between the seal surface 21 and the sliding surface 31 when the fixed disk 20 has a convex shape in which the central portion of the seal surface 21 protrudes toward the sliding surface 31.

When the drive disk 30 rotates due to the rotational force of the drive unit 40, the sliding surface 31 slides against the seal surface 21, generating a frictional force between the seal surface 21 and the sliding surface 31. This frictional force is generated when the drive disk 30 rotates with the sliding surface 31 biasing against the seal surface 21 due to the biasing force generated by the compression spring 90.

The frictional force generated by the rotation of the drive disk 30 in this way is such that, if the force with which the sliding surface 31 urges the seal surface 21 is constant across the entire seal surface 21, the greater the distance from the rotation axis of the drive disk 30, the greater the frictional force. In contrast, if the force with which the sliding surface 31 urges the seal surface 21 is constant across the entire seal surface 21, the frictional force generated by the rotation of the drive disk 30 is such that the greater the distance from the rotation axis of the drive disk 30, the smaller the frictional force.

In other words, if the force with which the sliding surface 31 urges the seal surface 21 is constant across the entire seal surface 21, the frictional force generated between the seal surface 21 and the sliding surface 31 increases the farther it is from the shaft axis CL. Therefore, the frictional force generated between the seal surface 21 and the sliding surface 31 is less affected by the frictional force in areas closer to the shaft axis CL, and is more affected by the frictional force in areas farther from the shaft axis CL.

In contrast, the fixed disk 20 of this embodiment has a convex shape formed by the central portion of the seal surface 21 protruding toward the sliding surface 31. Therefore, the reaction force that the sliding surface 31 receives when it presses against the seal surface 21 is greatest at the central portion of the sliding surface 31, and decreases as it moves away from the central portion of the sliding surface 31 in the radial direction DRr toward the outer circumferential surface.

As a result, of the frictional forces generated between the seal surface 21 and the sliding surface 31, the frictional force around the center of each surface is large, but the frictional force generated in the portion away from the center of each surface in the radial direction DRr can be reduced. In other words, if the central portion of the seal surface 21 is not formed so that it protrudes toward the sliding surface 31, the frictional force generated in the portion away from the central portion of each seal surface 21 and sliding surface 31 in the radial direction DRr, which tends to be large, can be reduced. As a result, of the frictional forces generated between the seal surface 21 and the sliding surface 31, the frictional force generated in the portion farther from the shaft axis CL, which has a greater impact, can be suppressed.

This reduces the maximum value of the rotational force that can be output by the drive unit 40 compared to a shape in which the central portion of the sealing surface 21 does not protrude toward the sliding surface 31.

Furthermore, in this embodiment, the sliding surface 31 of the drive disk 30 is pressed against the sealing surface 21, and is shaped to match the shape of the sealing surface 21. As a result, a reaction force is generated in the central portion of the sliding surface 31 as it tries to return to its deformed state after being pressed, and the reaction force received by the central portion of the sliding surface 31 becomes even greater.

As a result, of the frictional forces generated between the seal surface 21 and the sliding surface 31, the frictional forces at the central portions of the seal surface 21 and the sliding surface 31 can be increased, while the frictional forces generated at portions away from the central portions in the radial direction DRr can be reduced. This reduces the frictional forces generated at portions away from the central portions of the seal surface 21 and the sliding surface 31 in the radial direction DRr, further suppressing the maximum value of the rotational force that can be output by the drive unit 40.

As described above, the valve device 1 of this embodiment comprises a housing 10 that defines a fluid passage F therein for fluid flow, a fixed disk 20 that is disposed inside the housing 10 and defines a flow path hole 23 through which the fluid flows, and a drive unit 40 that outputs rotational force. The valve device 1 further comprises a shaft 50 that rotates about the shaft axis CL, and a drive disk 30 that increases or decreases the opening of the flow path hole 23 as the shaft 50 rotates, sliding against the fixed disk 20 and rotating about the shaft axis CL. The fixed disk 20 has a seal surface 21 facing the drive disk 30 on the upward direction DRa2 side. The drive disk 30 has a sliding surface 31 on the downward direction DRa1 side that slides against the seal surface 21. The fixed disk 20 has a convex shape in which the central portion of the seal surface 21 protrudes toward the sliding surface 31 compared to the remaining portions.

This reduces the frictional force that occurs in the areas away from the center of each surface in the radial direction DRr, which tends to be large if the center portions of both the seal surface 21 and the sliding surface 31 do not protrude toward the other surface. Therefore, the maximum value of the rotational force that can be output by the drive unit 40 can be reduced compared to when the center portions of both the seal surface 21 and the sliding surface 31 do not protrude toward the other surface.

Furthermore, the above embodiment can achieve the following effects:

(1) In the above embodiment, the fixed disk 20 has a surface treatment in which the sealing surface 21 is covered with a coating material 25, resulting in a convex shape in which the central portion of the sealing surface 21 protrudes toward the sliding surface 31.

This makes it easier to form a slight convex shape, such as a few microns to a few tens of microns, compared to methods that involve machining the fixed disk 20 to create a convex shape.

(2) In the above embodiment, the coating material 25 has a smaller Young's modulus than the fixed disk 20.

This allows the sealing surface 21 to be surface treated by covering it with a coating material 25, making it easier to deform the fixed disk 20 when internal stress is generated in the fixed disk 20 and the fixed disk 20 is deformed.

(3) In the above embodiment, a compression spring 90 is provided to bias the drive disk 30 against the fixed disk 20.

This makes it easier to maintain the sliding surface 31 of the drive disk 30 in contact with the sealing surface 21 of the fixed disk 20.

(4) In the above embodiment, the valve device 1 includes a lever 60 that is fixed to the drive disc 30 and connects the drive disc 30 and shaft 50 so that they can rotate together. The drive disc 30 has a press-fit groove 33 into which the lever 60 is press-fitted, located at a portion spaced apart from the shaft axis CL in the radial direction DRr. The compression spring 90 biases the drive disc 30 against the fixed disc 20 via the lever 60. The lever 60 transmits the force biased by the compression spring 90 to the press-fit groove 33 in the drive disc 30.

As a result, when the sliding surface 31 of the drive disk 30 presses against the seal surface 21 of the fixed disk 20, the biasing force of the compression spring 90 is transmitted not only to the central portion of the seal surface 21, but also to the portion close to the outer periphery. This makes it easier for the shape of the sliding surface 31 to follow the shape of the seal surface 21. This in turn makes it easier to maintain contact between the seal surface 21 and the sliding surface 31.

(Other embodiments)
Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as follows.

In the above embodiment, an example was described in which a surface treatment was used to generate internal stress in the fixed disk 20, causing the fixed disk 20 to have a warped shape. In contrast, an example was described in which the drive disk 30 was not surface-treated to cause the drive disk 30 to have a warped shape, and the sliding surface 31 was approximately parallel to the radial direction DRr before being placed in the valve device 1. However, the shapes of the fixed disk 20 and the drive disk 30 are not limited to this. Modified examples of the shapes of the fixed disk 20 and the drive disk 30 will be described with reference to Figures 12 to 16. Note that Figures 12 to 16 show the shapes of the fixed disk 20 and the drive disk 30 before being placed in the valve device 1, and in a state where they are not being pressed by the compression spring 90.

For example, as shown in FIG. 11, the drive disk 30 may be formed with a shape that warps in the same direction as the fixed disk 20. In other words, the sliding surface 31 of the drive disk 30 that faces the seal surface 21 may not be flat along the radial direction DRr, but may be formed to be recessed in the direction in which the seal surface 21 protrudes. In this case, the drive disk 30 may be formed with a warped shape by applying a surface treatment similar to that applied to the seal surface 21 of the fixed disk 20 to the surface opposite the sliding surface 31.

Alternatively, as shown in FIG. 12, the fixed disk 20 may be formed in a shape other than a warped shape. For example, the fixed disk 20 may have a shape in which the central portion of the seal surface 21 protrudes toward the sliding surface 31, and the support surface 22 may be formed in a flat shape along the radial direction DRr. In this case, the fixed disk 20 may be formed in a shape in which the central portion of the seal surface 21 protrudes toward the sliding surface 31, without applying a surface treatment to the seal surface 21.

Alternatively, as shown in FIG. 13, the drive disk 30 may be formed with a warped shape such that the sliding surface 31 protrudes toward the sealing surface 21. In this case, the drive disk 30 may be formed with a warped central portion of the sliding surface 31 by subjecting the sliding surface 31 to a surface treatment similar to that applied to the sealing surface 21 of the fixed disk 20.

Alternatively, as shown in Figures 14 and 15, the fixed disk 20 may have the sealing surface 21 protruding toward the sliding surface 31 and the support surface 22 formed as a flat surface along the radial direction DRr. In this case, the drive disk 30 may be formed in a warped shape so that the sliding surface 31 protrudes toward the sealing surface 21, as shown in Figure 14. Alternatively, the drive disk 30 may have the sliding surface 31 protruding toward the sealing surface 21 and the side opposite the sliding surface 31 formed as a flat surface along the radial direction DRr, as shown in Figure 15.

Alternatively, as shown in FIG. 16, the fixed disk 20 may be formed in a warped shape so that the seal surface 21 protrudes toward the sliding surface 31. In this case, the drive disk 30 may be formed so that the sliding surface 31 protrudes toward the seal surface 21, and the side opposite the sliding surface 31 is flat along the radial direction DRr.

In the above embodiment, an example was described in which the valve device 1 is provided with a lever 60 that connects the drive disc 30 and the shaft 50 so that they can rotate together, but this is not limiting. For example, the valve device 1 may not be provided with a lever 60, and the compression spring 90 may directly press against the drive disc 30.

In the above embodiment, the valve device 1 has been described as being used in a fluid circulation system mounted on, for example, an electric vehicle or a hybrid vehicle, but this is not limiting. For example, the valve device 1 may be used in a fluid circulation system mounted on a vehicle other than an electric vehicle or a hybrid vehicle. The valve device 1 may also be used for applications other than vehicles.

In the above embodiment, the fluid flowing through the fluid passage F within the housing 10 of the valve device 1 was described as coolant, but this is not limited to this. For example, the fluid may be a liquid or gas other than coolant.

It goes without saying that in the above-described embodiments, the elements that make up the embodiments are not necessarily essential, except in cases where they are specifically stated as essential or where they are clearly considered essential in principle.

In the above-described embodiments, when numerical values such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to those specific numbers unless expressly stated as being essential or unless they are clearly limited to a specific number in principle.

In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., there is no limitation to those shapes, positional relationships, etc., unless otherwise specified or in principle limited to specific shapes, positional relationships, etc.

Claims (5)

A valve device,
a housing (10) that defines a fluid passage (F) for allowing a fluid to flow therethrough;
a fixed disk (20) disposed inside the housing and having at least one flow path hole (23) formed therein through which the fluid flows;
a drive unit (40) that outputs a rotational force;
a shaft (50) that rotates about a shaft axis (CL) by the rotational force output by the drive unit;
a drive disk (30) that increases or decreases the opening degree of the flow path hole in accordance with the rotation of the shaft, and that slides on the fixed disk and rotates around the shaft axis,
The fixed disk has a seal surface (21) facing the drive disk on one side in the direction in which the shaft axis extends,
The drive disk has a sliding surface (31) that slides against the seal surface on the other side in the direction in which the shaft axis extends,
a central portion of at least one of the sealing surface and the sliding surface of the fixed disk and the driving disk has a convex shape formed so as to protrude toward the other surface compared to the other portion; The valve device described in claim 1, wherein the convex shape of the fixed disk and the drive disk is formed by surface treatment in which at least one of the sealing surface and the sliding surface is covered with a coating material. The valve device described in claim 2, wherein the coating material has a smaller Young's modulus than the fixed disk and the drive disk. A valve device as described in any one of claims 1 to 3, comprising a biasing portion (90) that biases the drive disk against the fixed disk. a lever (60) fixed to the drive disk and connecting the drive disk and the shaft so that they can rotate together;
When a direction extending radially from the shaft axis as a center is defined as a radial direction, the drive disk has a connecting portion (33) to which the lever is connected at a portion spaced apart from the shaft axis in the radial direction,
the biasing portion biases the drive disk toward the fixed disk via the lever,
The valve device according to claim 4 , wherein the lever transmits the force exerted by the biasing portion to the connecting portion of the drive disk.