Switching valve

Abstract

The purpose of the present invention is to provide a selector valve wherein contact resistance when a valve body moves along a seat surface of a housing is small.　A selector valve V has a valve body 50 that abuts a seat surface 34 of a housing 10 comprising a plurality of openings 40–43 and that selectively connects at least two openings among the plurality of openings 40–43, and said selector valve V is such that fluid pressure is imparted to a back face 55 of the valve body 50, and moreover, said selector valve V has a biasing means 90 that biases the valve body 50 in a direction away from the seat surface 34 of the housing 10.

Description

[Technical Field]

[0001] The present invention relates to a switching valve that switches a flow path through which a fluid flows. [Background technology]

[0002] In various industrial fields, fluid circuits are used in which a fluid supply source, a fluid working device, or a heat exchanger is connected in a circular manner by a flow path. In such fluid circuits, a switching valve that switches the flow path of the working fluid may be provided, thereby enabling a single fluid circuit to perform multiple functions.

[0003] For example, the switching valve in Patent Document 1 switches the fluid circuit that constitutes a heat pump that uses the heat of vaporization and condensation of a heat medium. The heat pump has a compressor, a first outdoor heat exchanger, an expansion valve as a pressure reducing means for expanding the heat medium, and a second indoor heat exchanger, with the first heat exchanger, expansion valve, and second heat exchanger connected in series. The switching valve switches between the first and second heat exchangers connected directly downstream of the compressor, thereby switching between cold air operation and warm air operation.

[0004] The switching valve is primarily composed of a valve disc rotated by a motor and a housing with a seating surface against which the valve disc abuts. The valve disc is accommodated within the space within the housing. The housing's seating surface has four equally spaced openings: an inlet opening connected to the compressor's discharge side, an outlet opening connected to the compressor's suction side, a first opening connected to the first heat exchanger, and a second opening connected to the second heat exchanger. The valve disc, which moves along the housing's seating surface and abuts against it, has a circumferentially extending communication groove at its front abutment. Rotating the valve disc connects the outlet opening to the first opening through the communication groove, and also connects the inlet opening to the second opening through the space within the housing. Rotating the valve disc to the opposite side connects the outlet opening to the second opening through the communication groove, and also connects the inlet opening to the first opening through the space within the housing. [Prior art documents] [Patent documents]

[0005] Patent Document 1: Japanese Utility Model Application No. 2-22088 (Japanese Utility Model Application No. 2002-22088) 3-114681 Microfilm of No. 7-11 (Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In a switching valve such as that in Patent Document 1, when a heat pump is in use to perform heating or cooling operation, the pressure of the heat medium on the discharge side supplied to the space in the housing acts on the back side of the valve disc, and the pressure of the heat medium on the suction side supplied to the communicating groove, i.e., the pressure of the heat medium decompressed by the expansion valve, acts on the abutting part of the valve disc. The pressure of the heat medium supplied to the space in the housing is higher than the pressure of the heat medium supplied to the communicating groove, and the valve disc is pressed against the seating surface and sealed, preventing the heat medium on the discharge side from directly flowing into the communicating groove or the suction port.

[0007] However, when switching between warm air operation mode and cold air operation mode, when the valve body is rotated to switch the flow path, the valve body is pressed against the seating surface of the housing due to the differential pressure of the heat medium acting on the back surface of the valve body and the inner surface of the connecting groove, and the weight of the valve body.As the valve body rotates, the abutment part of the valve body and the seating surface of the housing slide together, creating contact resistance, and also causing scratches on the abutment part of the valve body and the seating surface of the housing, which could lead to leakage of the heat medium.

[0008] The present invention has been made in view of these problems, and has as its object to provide a switching valve in which the contact resistance when the valve element moves along the seating surface of the housing is small. [Means for solving the problem]

[0009] In order to solve the above problem, the switching valve of the present invention comprises: A switching valve having a valve body that abuts against a seat surface of a housing having a plurality of openings and selectively connects at least two of the plurality of openings, and that is configured to apply fluid pressure to a back surface of the valve body, The valve body has a biasing means for biasing the valve body in a direction away from the seating surface of the housing. According to this, when the differential pressure of the fluid acting on the back side and front side of the valve body is small or zero, the normal resistance between the valve body and the seating surface of the housing is small or zero due to the biasing means, so that the contact resistance when the valve body moves along the seating surface of the housing due to switching of the switching valve is small.

[0010] The switching valve has a rotor, a stator, a rotor shaft, and a rotor case, and both ends of the rotor shaft are journaled. The valve element is arranged to be movable in the axial direction together with the rotary shaft. It's fine. This allows the valve body to move smoothly in the axial direction with a simple configuration.

[0011] A spring may be provided around the rotation shaft as the biasing means. This allows the valve element to be moved accurately in the axial direction.

[0012] The housing may have a bottomed opening in which the end of the rotary shaft and at least a part of the biasing means are disposed. According to this, by arranging at least a part of the biasing means in the bottomed opening, the distance between the valve body and the seating surface of the housing can be shortened, thereby making it less susceptible to the influence of fluid pressure between the valve body and the seating surface of the housing.

[0013] The valve body may be formed with a bottomed opening into which the end of the rotary shaft and at least a part of the biasing means are inserted. According to this, by arranging at least a part of the biasing means in the bottomed opening, the distance between the valve body and the seating surface of the housing can be shortened, thereby making it less susceptible to the influence of fluid pressure between the valve body and the seating surface of the housing.

[0014] A communication passage may be formed in at least one of the rotor, the rotary shaft, and the rotor case, the communication passage communicating in the axial direction. With this, when the switching valve is switched, the fluid passes through the connecting passage as the valve body, rotor, and rotating shaft move axially, so that fluid resistance is small and the valve body can be smoothly and reliably separated from the seating surface of the housing.

[0015] The valve body may have a seal material that selectively surrounds at least two of the plurality of openings provided in the seating surface of the housing. With this, the normal force between the valve body and the seating surface of the housing is reduced by the biasing means, which prevents the seal material from being scratched by the edge of the opening when the valve body moves parallel to the seating surface of the housing, thereby maintaining high sealing performance of the seal material.

[0016] The housing may be provided with an introduction port for introducing a fluid, and may also be formed with a space that accommodates the valve body and to which the fluid is supplied from the introduction port. With this, the high pressure of the fluid supplied to the space from the inlet port acts on the back side of the valve body, and the valve body can be reliably pressed against the seating surface of the housing. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing a heat pump to which a switching valve according to a first embodiment of the present invention is applied. [Figure 2] 1 is a side cross-sectional view of the switching valve of the first embodiment when the valve body is stopped in one switching state. FIG. [Figure 3] 3 is a view showing one switching state of the switching valve as viewed from the arrow AA in FIG. 2.

[0023] FIG. [Figure 4] 3 is a view showing another switching state of the switching valve as viewed from the arrow AA in FIG. 2. FIG. [Figure 5] 3 is a side cross-sectional view of the switching valve of the first embodiment when the valve body rotates in one switching state. FIG. [Figure 6] FIG. 2 is a side cross-sectional view showing a first modified example of the switching valve of the first embodiment. [Figure 7] 10 is a cross-sectional view showing a main part of a second modified example of the switching valve of the first embodiment. FIG. [Figure 8] FIG. 10 is a cross-sectional view showing a main part of a third modified example of the switching valve of the first embodiment. [Figure 9] FIG. 4 is a side cross-sectional view of a switching valve according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A switching valve according to an embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0019] The switching valve according to the first embodiment will be described with reference to Figs. 1 to 5. In the following description, the top and bottom of Fig. 2 will be referred to as the top and bottom of the switching valve. In particular, the top side of the page where the stepping motor 80 is located will be referred to as the top side of the switching valve, and the bottom side of the page where the housing is located will be referred to as the bottom side of the switching valve. In addition, in the present invention, the top side of the valve disc will be referred to as the back side and the bottom side will be referred to as the front side, with the valve disc as the reference.

[0020] As shown in FIG. 1, the switching valve V of the present invention, together with a compressor C, a first heat exchanger H1, an expansion valve E, a second heat exchanger H2, etc., constitutes a heat pump R that supplies cold air and warm air to an automobile or the like.

[0021] First, the heat pump R will be described. As shown in Fig. 1, the switching valve V switches the flow path downstream of the compressor C in the fluid circuit of the heat pump R so that in a cold air operation mode in which cold air is supplied, the heat medium flows through the first heat exchanger H1, the expansion valve E, and the second heat exchanger H2 in that order, as shown by the solid line in Fig. 1, and in a cold air operation mode in which warm air is supplied, the switching valve V switches the flow path so that the refrigerant flows through the second heat exchanger H2, the expansion valve E, and the first heat exchanger H1 in that order, as shown by the dotted line in Fig. 1. As a result, in the cold air operation mode, the first heat exchanger H1 functions as a condenser and the second heat exchanger H2 functions as an evaporator, and in the heating operation mode, the second heat exchanger H2 functions as a condenser and the first heat exchanger H1 functions as an evaporator.

[0022] Next, the structure of the switching valve V will be described with reference to Figures 2 to 4. The switching valve V is an electric motor-operated rotary valve mainly comprising a housing 10 made of a metal or resin material, a valve element 50 disposed within the housing 10, a stepping motor 80 fixed to the housing 10 for driving the valve element 50, and a coiled wave spring 90 as a biasing means. The switching valve V is a so-called four-way valve to which four flow paths are connected.

[0023] In addition, for the sake of convenience, in Figures 3 and 4, the four ports 40 to 43 to which the four flow paths that cannot be seen when viewed from the AA arrows in Figure 2 are connected are shown by dashed double-dashed lines, while the coiled wave spring 90 is not shown.

[0024] The housing 10 is composed of a cylindrical cover body 20 with a step on the inner diameter side, and a disk-shaped bottom body 30 with a step on the outer diameter side.

[0025] The cover body 20 has formed therein, in order from the upper axial side, an opening 21 that opens axially upward and has a stepped cross section, a small-diameter through-portion 22 that is continuous with the opening 21 and has a smaller diameter than the opening 21, a medium-diameter through-portion 23 that is continuous with the small-diameter through-portion 22 and has a stepped cross section and a larger diameter than the small-diameter through-portion 22, and a large-diameter through-portion 24 that is continuous with the medium-diameter through-portion 23 and has a larger diameter than the medium-diameter through-portion 23. The opening 21, the small-diameter through-portion 22, the medium-diameter through-portion 23, and the large-diameter through-portion 24 penetrate the cover body 20 in the axial direction.

[0026] A cylindrical body 25 formed in a cylindrical shape with an outer diameter flange is inserted and disposed in the small diameter through-hole 22 and the medium diameter through-hole 23 of the cover body 20 from the lower side toward the upper side in the axial direction, with an O-ring interposed between the upper end surface of a flange portion 26 of the cylindrical body 25 and the bottom surface (in other words, the upper surface in FIG. 2) of the medium diameter through-hole 23. A can 81 of a stepping motor 80, which will be described later, is fixed to the cylindrical portion 27 of the cylindrical body 25, and a case that houses the can 81, stator 82, etc. of the stepping motor 80 is fixed to the cover body 20 using fixing members (not shown).

[0027] The bottom body 30 is formed with, in order from the upper axial side, a cylindrical portion 32 and a flange portion 31 extending radially outward from the cylindrical portion 32. The cylindrical portion 32 is press-fitted and fixed to the lower end of the large-diameter through-portion 24 of the cover body 20 with an O-ring interposed between the inner peripheral surface of the large-diameter through-portion 24 and the outer peripheral surface of the cylindrical portion 32, and together with the cover body 20, forms the housing 10.

[0028] As shown in FIGS. 3 and 4, the bottom body 30 has four ports 40 to 43, which are a plurality of openings that penetrate the bottom body 30 in the axial direction, arranged at equal intervals.

[0029] More specifically, the arrangement order of ports 40 to 43, that is, with the upper side at 12 o'clock in Figure 3, starting from port 40 located at the 9 o'clock position and proceeding in a clockwise direction as indicated by the solid white arrow in the same figure, is as follows: inlet port 40 connected to the discharge side of compressor C between compressor C and first heat exchanger H1; first port 41 connected to the first heat exchanger H1 side between compressor C and first heat exchanger H1; outlet port 42 connected to the suction side of compressor C between compressor C and second heat exchanger H2; and second port 43 connected to the second heat exchanger H2 side between compressor C and second heat exchanger H2.

[0030] 3 and 4, the clockwise direction indicated by the solid white arrow and the counterclockwise direction indicated by the dotted white arrow are the directions in which the valve element 50 is rotated by the stepping motor 80.

[0031] In addition, pin-shaped regulating portions 33 are fixed to the bottom body 30 between the inlet port 40 and the first port 41, and between the outlet port 42 and the second port 43, so as to extend upward from the upper end surface 34 of the cylindrical portion 32, which serves as the seat surface of the housing.

[0032] As shown in FIG. 2, a stepped recess 35 is formed in the radial center of the bottom body 30 as a bottomed opening. More specifically, from the axially upper side, a stepped large-diameter hole 36 is formed, which opens axially upward, and a small-diameter recess 37 is formed, which is continuous with the large-diameter hole 36 and has a smaller diameter than the large-diameter hole 36 and a concave cross-section.

[0033] As shown in Figures 3 and 4, the valve body 50 is formed in a plate shape that is roughly circular in shape when viewed from above, and its radius is slightly smaller than the radius of the inner surface of the large-diameter through-hole 24 of the housing 10.The valve body 50 is housed between the two restriction portions 33 in the circumferential direction and on the outlet port 42 side.

[0034] 2, the valve body 50 is formed with a small-diameter through-portion 51 having a small diameter, and a large-diameter through-portion 52 that is continuous with the lower end of the small-diameter through-portion 51 and serves as a bottomed opening having a stepped cross section and a larger diameter than the small-diameter through-portion 51. The small-diameter through-portion 51 and the large-diameter through-portion 52 penetrate the valve body 50 in the axial direction.

[0035] The inner diameter of the large diameter through portion 52 is approximately the same as the inner diameter of the large diameter hole portion 36 of the bottom body 30 .

[0036] As shown in Figures 2 to 4, the valve body 50 has a communicating groove 53 recessed axially upward from its lower end surface in the axial direction, which has a bullet-shaped cross section as viewed in the radial direction (see Figure 2) and an approximately quarter-arc shape along the circumferential direction as viewed in the axial direction (see Figures 3 and 4).

[0037] More specifically, the communicating groove 53 is arranged and formed so that the ports 42 and 43 can communicate with each other when the valve body 50 is rotated clockwise in Figures 3 and 4, and so that the ports 41 and 42 can communicate with each other when the valve body 50 is rotated counterclockwise in Figures 3 and 4.

[0038] In addition, an O-ring 54 serving as a sealing material is inserted into and fixed to a groove 59 in the valve body 50. The groove 59 is recessed axially upward from the lower end face of the valve body 50 along the periphery of the communicating groove 53, and has right angles at both ends in a cross-sectional view (see Figure 2), is endless, and is annular when viewed from below (see Figures 3 and 4).

[0039] As shown in Figure 2, the stepping motor 80 is mainly composed of a cylindrical can 81 with a bottom as a rotor case, a stator 82 arranged on the outer diameter side of the can 81 and equipped with a coil, a rotor 83 arranged on the inner diameter side of the can 81 and having multiple permanent magnets fixed to the outer periphery of a base member, a rotating shaft 84 inserted into and fixed to the rotor 83, and a bearing 85 arranged and fixed to the bottom of the can 81.

[0040] The stepping motor 80 is fixed to the housing 10 by fixing the can 81 to the cylindrical portion 27 of the cylindrical body 25, with the lower end of the can 81 fitted into the upper end of the cylindrical portion 27 of the cylindrical body 25, and a case that houses the can 81, stator 82, etc. of the stepping motor 80 is fixed to the cover body 20 using a fixing member (not shown). Note that the stepping motor 80 may be fixed to the housing 10 by fixing the can 81 to the cylindrical portion 27 of the cylindrical body 25, and the fixing method may be changed as appropriate.

[0041] The rotating shaft 84 is formed in a stepped cylindrical shape, and is formed, from the upper axial side, with an upper detailed portion 84a, a thick portion 84b that is connected to the lower end of the upper detailed portion 84a and is thicker than the upper detailed portion 84a, and a lower detailed portion 84c that is connected to the lower end of the thick portion 84b and is thinner than the thick portion 84b.

[0042] The outer diameter of the upper narrow portion 84a of the rotary shaft 84 is formed to be slightly smaller than the inner diameter of the bearing 85, and the rotary shaft 84 is inserted into the bearing 85 so as to be rotatable and movable in the vertical direction.

[0043] The upper detailed portion 84 a is press-fitted into a through-hole in the rotor 83 and fixed to the rotor 83 .

[0044] The thick portion 84b of the rotating shaft 84 has an outer diameter that is slightly larger than or approximately the same as the inner diameter of the small diameter through portion 51 of the valve body 50, and is pressed into the small diameter through portion 51 and fixed to the valve body 50.

[0045] In addition, the lower portion 84c of the rotating shaft 84 is formed with a diameter smaller than the inner diameter of the bearing 91 fixed to the small diameter recess 37 of the bottom body 30, and is inserted into the bearing 91 so as to be rotatable and movable in the vertical direction.

[0046] In this way, the valve element 50, the rotor 83, and the rotary shaft 84 are fixed together, and are all capable of rotating in the same direction and moving in the axial direction.

[0047] The lower detail portion 84c is passed through a coiled wave spring 90 and an annular thin plate 92 in this order from the axially lower side.

[0048] The coiled wave spring 90 has its upper end abutting the lower end surface of the annular thin plate 92 and its lower end abutting the bottom surface of the large diameter hole portion 36 (in other words, the lower surface in Figure 2), and urges the valve body 50 axially upward via the annular thin plate 92.

[0049] The annular thin plate 92 is made of a low-friction material such as PTFE (polytetrafluoroethylene), and is fixed to the large-diameter through-hole 52 .

[0050] Furthermore, the upper end surface of the annular thin plate 92 is in face contact with the lower end surface of the thick portion 84b of the rotating shaft 84 and the bottom surface of the large-diameter through portion 52 of the valve body 50, which is approximately flush with this lower end surface, and therefore the biasing force of the coiled wave spring 90 is transmitted to both the valve body 50 and the rotating shaft 84.

[0051] Furthermore, the annular thin plate 92 is formed from a low-friction material, which makes it difficult for the rotation of the valve element 50 and the rotating shaft 84 to be transmitted to the coiled wave spring 90. As a result, friction is less likely to occur between the valve element 50 and the rotating shaft 84 and the coiled wave spring 90 when the valve element 50 rotates. This reduces the driving force required for rotation and suppresses wear on the valve element 50, the rotating shaft 84, and the coiled wave spring 90.

[0052] The annular thin plate 92 may be omitted, but it is preferable to take low-friction measures such as interposing a coating layer of a low-friction material or a bearing between the valve body 50, the rotating shaft 84, and the coiled wave spring 90 in order to reduce friction between the valve body 50, the rotating shaft 84, and the coiled wave spring 90.

[0053] Inside the housing 10, a back pressure chamber 11 is defined as a space into which fluid is supplied from the inlet port by the cover body 20, the cylindrical body 25, the upper end surface 34 of the bottom body 30, the valve body 50, and the can 81.

[0054] As described above, the valve element 50 is disposed between the two restriction portions 33, and is restricted from moving toward the inlet port 40. In other words, the inlet port 40 always communicates with the back pressure chamber 11, and when the compressor C is operating, the high-pressure heat transfer medium discharged from the compressor C is introduced into the inlet port 40.

[0055] As a result, when the heat pump is in use with the compressor C driving the valve body 50, the pressure of the heat medium discharged from the compressor C acting on the upper end surface 55, which is the back surface of the valve body 50, in the back pressure chamber 11 is higher than the pressure of the heat medium reduced in pressure by the expansion valve E acting on the inner surface of the communicating groove 53, which is the front surface of the valve body 50.

[0056] The force exerted by the heat medium in the back pressure chamber 11 in the direction of pressing the valve body 50 against the upper end surface 34 of the bottom body 30 exceeds the sum of the force exerted by the heat medium in the communicating groove 53 in the direction of moving the valve body 50 away from the upper end surface 34 of the bottom body 30 and the force exerted by the coiled wave spring 90 in the direction of moving the valve body 50 away from the upper end surface 34 of the bottom body 30.

[0057] Therefore, as shown in Figure 2, the valve body 50, more specifically the O-ring 54, is pressed and sealed against the upper end surface 34 of the bottom body 30, preventing the heat transfer medium discharged from the compressor C from flowing directly into the communicating groove 53 or the outlet port 42.

[0058] Next, switching of the flow paths of the fluid circuit by the switching valve V will be described with reference to Figures 3 to 5. In this explanation, switching from a state in which ports 42, 43 are connected by the communication groove 53 of the valve element 50 as shown in Figure 3 to a state in which ports 41, 42 are connected by the communication groove 53 of the valve element 50 as shown in Figure 4 will be described.

[0059] When the flow path of the fluid circuit is switched by the switching valve V, the operation of the compressor C is stopped. With the compressor C stopped, the heat transfer medium pressure on the discharge side and the heat transfer medium pressure on the suction side of the compressor C become closer to uniform over time, so the pressure difference of the heat transfer medium between the discharge side and the suction side of the compressor C becomes smaller compared to when the compressor C is operating.

[0060] Therefore, the force pressing the valve body 50 against the upper end surface 34 of the bottom body 30 due to the pressure difference between the heat transfer medium on the discharge side and the suction side of the compressor C is smaller than when the compressor C is operating, and the force of the coiled wave spring 90 moves the valve body 50 axially upward, as shown in Figure 5, and moves it away from the upper end surface 34 of the bottom body 30.

[0061] When the pressure difference is relatively large, the valve element 50 abuts against the upper end surface 34 of the bottom body 30, but the normal force acting on the valve element 50 from the upper end surface 34 is smaller than when the compressor C is operating. Unless otherwise specified, the following description will be given assuming that the valve element 50 is spaced apart from the upper end surface 34 of the bottom body 30.

[0062] At this time, the rotor 83 and the rotating shaft 84 move axially upward together with the valve body 50, and both ends of the rotating shaft 84 are guided axially by bearings 85, 91, so that the valve body 50 can be moved axially smoothly with a simple configuration.

[0063] Next, the stepping motor 80 is driven to rotate the rotary shaft 84, causing the valve element 50 to rotate counterclockwise from the position shown in FIG. 3, and the stepping motor 80 is stopped when the communicating groove 53 of the valve element 50 is aligned with the ports 41 and 42 as shown in FIG. 4.

[0064] Thereafter, by driving the compressor C, the pressure difference between the heat medium pressure on the discharge side and the heat medium pressure on the suction side increases, and as described above, the valve element 50 is pressed against and sealed to the upper end surface 34 of the bottom body 30. In this way, the switching valve V is able to switch the flow path of the fluid circuit so that the ports 41, 42 are communicated with each other when the valve element 50 is spaced from the upper end surface 34 of the bottom body 30.

[0065] Furthermore, when switching the fluid circuit from the state shown in Figure 4 to the state shown in Figure 3, the stepping motor 80 can be rotated in the reverse direction, the valve body 50 rotated clockwise, and the compressor C can be driven to switch.

[0066] As described above, in the switching valve V of this embodiment, when the pressure difference between the heat transfer medium acting on the upper end surface 55 of the valve body 50 and the inner surface of the communicating groove 53 is small or zero, the normal force between the valve body 50 and the upper end surface 34 of the housing 10 is small or zero due to the coiled wave spring 90, and therefore, when the switching valve V is switched, the contact resistance is small when the valve body 50 rotates along the upper end surface 34 of the housing 10.

[0067] Furthermore, a rotation shaft 84 is passed through the coiled wave spring 90, and the expansion and contraction of the coiled wave spring 90 is guided by the rotation shaft 84, so that the valve body 50 can be moved accurately in the axial direction.

[0068] Furthermore, the coiled wave spring 90 has an upper axial end located in the large diameter through-hole 52 of the valve body 50 and a lower axial end located in the large diameter hole 36 of the housing 10, which shortens the distance between the valve body 50 and the upper end surface 34 of the housing 10, making it less susceptible to the influence of fluid pressure between the valve body 50 and the upper end surface 34 of the housing 10.

[0069] Furthermore, the coiled wave spring 90 is inserted into the large diameter through-hole 52 of the valve element 50, which has a diameter slightly larger than that of the coiled wave spring 90, and the large diameter hole 36 of the housing 10. The expansion and contraction of the coiled wave spring 90 is guided by the inner circumferential surfaces of the large diameter through-hole 52 and the large diameter hole 36, allowing the valve element 50 to move accurately in the axial direction.

[0070] Furthermore, the normal force between the valve element 50 and the upper end surface 34 of the housing 10 is reduced by the coiled wave spring 90, which prevents the O-ring 54 from being scratched by the edges of the ports 41 to 43 when the valve element 50 rotates. This allows the O-ring 54 to maintain high sealing performance.

[0071] Although the valve body 50 has been described as moving together with the rotor 83 and the rotating shaft 84, this is not limited thereto, and the valve body and the rotating shaft may both move relative to the rotor, or the valve body may move relative to the rotating shaft.

[0072] [Variation 1] Next, a first modified example of the switching valve V will be described with reference to Fig. 6. The switching valve V of the first modified example is different from that of the first embodiment in that a communicating passage 83a penetrating in the axial direction is formed in the base material of the rotor 83, but the other configurations are the same as those of the first embodiment. As a result, when the switching valve V is switched, the fluid passes through the communicating passage 83a as the valve element 50, rotor 83, and rotary shaft 84 move in the axial direction, so that the fluid resistance of the rotor 83 is small and the valve element 50 can be smoothly and reliably separated from the upper end surface 34 of the housing 10.

[0073] The communicating passages are not limited to being formed in the rotor 83, but may also be formed in the can 81 or the rotating shaft 84. For example, the communicating passages may be formed by curving a portion of the peripheral wall of the can 81 toward the outer diameter. Furthermore, the communicating passages are not limited to being through holes, but may also be formed by cutting out the outer peripheral surface of the rotor 83 or the rotating shaft 84 in the inner diameter direction. Furthermore, the number of communicating passages is not limited, but is preferably multiple from the viewpoints of structural strength and preventing uneven distribution of fluid.

[0074] [Variation 2] Next, a second modification of the switching valve V will be described with reference to Fig. 7. The switching valve V of the second modification is different from that of the first embodiment in that the ports 41 and 43 are arranged near the outlet port 42, but the other configurations are the same as those of the first embodiment. With this configuration, the rotation range of the valve element 150 is narrow, being within 180 degrees, and the length of the communication groove 53 can be shortened, so that the valve element 150 can be made smaller.

[0075] [Variation 3] Next, a third modification of the switching valve V will be described with reference to Fig. 8. The switching valve V of the third modification differs from that of the first embodiment in that, when the compressor C is driven, the axial center R1 of the rotor 83 is positioned lower than the axial center S1 of the stator 82, as shown in the left half of Fig. 8, and when the valve body 50 is rotated, the axial center S1 of the stator 82 and the axial center R1 of the rotor 83 are aligned so as to be arranged on the same straight line, as shown in the right half of Fig. 8. The other configurations are the same as those of the first embodiment.

[0076] With this configuration, the electromagnetic force generated by energizing the stator 82 acts to move the rotor 83 axially upward, thereby assisting the axial movement of the valve body 50 caused by the biasing force of the coiled wave spring 90.

[0077] In this way, the biasing means is not limited to the coiled wave spring 90, and other biasing means may be used in combination.

[0078] The biasing means may be merely an electromagnetic force generated by energizing the stator 82 .

[0079] Here, the variations 1 to 3 may be used in combination with one another. [Example]

[0080] An expansion valve according to Example 2 will be described with reference to Fig. 9. Note that a description of the same configuration as in Example 1 will be omitted. In this description, the right side of the page where the motor 280 is located will be referred to as the right side of the switching valve, and the opposite left side of the page will be referred to as the left side of the switching valve.

[0081] As shown in FIG. 9, in this embodiment, the switching valve V200 is mainly composed of a housing 210, a valve element 250 arranged in the housing 210, and a motor 280, and by driving the motor 280, the valve element 250 can be caused to reciprocate in the axial direction.

[0082] The housing 210 has an inlet port 240 at its upper end, and a piping section 230 at its lower end, in which a first port 241, an outlet port 242, and a second port 243 are arranged in parallel.

[0083] As shown in FIG. 9(a), the upper end surface 233 of the piping section 230 serves as a seat surface against which the valve body 250 is pressed by the pressure difference when the compressor C is driven.

[0084] The valve body 250 is formed in a cylindrical shape with a step on the outer diameter side, and a communication groove 253 that opens downward is formed in the base located in the axial center.

[0085] As a result, when the valve element 250 is moved axially to the left, the ports 242 and 243 are communicated with each other and the ports 240 and 241 are also communicated with each other through the communication groove 253. When the valve element 250 is moved axially to the right, the ports 241 and 242 are communicated with each other and the ports 240 and 241 are also communicated with each other through the communication groove 253.

[0086] Further, thick end portions 251, 252, which are located at both axial ends of valve body 250 and have a larger diameter than the base portion, are formed with recesses 255 recessed upward from the lower end surfaces. A coil spring 256 serving as a biasing means is inserted into recess 255, and a low-friction member 257 made of a low-friction material is fixed to the lower end of coil spring 256.

[0087] As a result, when switching the flow path of the fluid circuit using the switching valve V200, as shown in Figure 9(b), each coil spring 256 separates the valve body 250 from the upper end surface 233 of the housing 210, and the normal force acting on the valve body 250 from the upper end surface 233 is approximately zero, allowing the valve body 250 to be moved in the axial direction with a small driving force and making the valve body 250 less likely to be damaged.

[0088] Furthermore, the low-friction member 257 reduces the friction generated between the coil spring 256 and the inner peripheral surface of the housing 210, allowing the valve element 250 to move smoothly.

[0089] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0090] For example, in the first and second embodiments, the switching valve is described as being a four-way valve having four ports, but the present invention is not limited to this, and the number of ports may be five or more.

[0091] In the first and second embodiments, the communication groove of the valve disc is configured to selectively communicate with two ports, but this is not limiting and three or more ports may be selectively communicated with. The same applies to the space on the back side of the valve disc, i.e., the back pressure chamber side.

[0092] In addition, in the first and second embodiments, the valve element is described as being rotated or reciprocated by a motor, but this is not limiting and the valve element may be manually operated or may be appropriately changed to a drive source other than a motor.

[0093] In addition, in the first embodiment, examples of the biasing means include a coiled wave spring, electromagnetic force, and a coil spring, but the biasing means is not limited to these and may be any well-known spring such as a disc spring or a leaf spring, or may be any of various cylinders, and may be changed as appropriate as long as it is capable of applying a biasing force.

[0094] Furthermore, in the first and second embodiments, the biasing means is exemplified as a coiled wave spring or a coil spring that is separate from the valve body or the housing, but the biasing means is not limited to this, and may be configured to have a spring portion having elasticity that is integrally formed by cutting out a part of the valve body or the housing.

[0095] In addition, in the first embodiment, the sealing material is described as an O-ring, but this is not limited to this, and any well-known sealing material may be used, such as an X-packing having an X-shaped cross section, a Y-packing having a Y-shaped cross section, a gasket, etc. Furthermore, the sealing material is not limited to a separate sealing material from the valve body, and may be a bead formed on the lower end surface of the valve body for sealing.

[0096] In addition, in the first embodiment, the O-ring as a sealing material is described as being inserted into and fixed to an annular groove formed in the valve body, but this is not limited thereto, and the O-ring may be welded or glued to the lower end surface of the valve body, and the fixing method may be changed as appropriate. [Explanation of symbols]

[0097] 10. Housing 11 Back pressure chamber (space to which fluid is supplied from the introduction port) 34 Top surface (housing seat surface) 35 Recess (opening with bottom) 40 Introduction port (opening) 41 First port (opening) 42 Outlet port (opening) 43 Second port (opening) 50 Valve body 54 O-ring (sealing material) 55 Top end surface (back) 81 Can (rotor case) 83 Rotor 83a Communication path 84 Rotational Axis 85 bearings 90 Coiled wave spring (biasing means) 91 Bearings 150 Valve body 210 Housing 233 Top surface (seat surface) 240 Introduction Port 241 Port 1 242 Derivation Port 243 Port 2 250 Valve body 256 Coil spring (biasing means) C Compressor E Expansion valve H1 1st heat exchanger H2 2nd heat exchanger R heat pump R1 Axial center of rotor S1 Axial center of stator V-switching valve V200 Switching Valve

Claims

1. A switching valve having a valve body that abuts against a seat surface of a housing having a plurality of openings, selectively communicating at least two of the plurality of openings, and capable of applying fluid pressure to a back surface of the valve body, a biasing means for biasing the valve body in a direction away from the seating surface of the housing, The switching valve has a rotor, a stator, a rotary shaft of the rotor, and a rotor case, and both ends of the rotary shaft are journaled. The valve element is a switching valve that is arranged to be movable in the axial direction together with the rotary shaft.

2. 2. A switching valve according to claim 1, wherein a spring is provided around the rotary shaft as the biasing means.

3. 3. The switching valve according to claim 1, wherein the housing has a bottomed opening in which the end of the rotary shaft and at least a part of the biasing means are disposed.

4. 4. The switching valve according to claim 1, wherein the valve body is formed with a bottomed opening into which the end of the rotary shaft and at least a part of the biasing means are inserted.

5. 5. A switching valve according to claim 1, wherein a communication passage is formed in at least one of said rotor, said rotary shaft and said rotor case, the communication passage communicating in the axial direction.

6. 6. The switching valve according to claim 1, wherein the valve body has a seal member that selectively surrounds at least two of the plurality of openings provided in the seating surface of the housing.

7. 7. A switching valve according to claim 1, wherein the housing has a space formed therein for accommodating the valve element and for receiving fluid from an inlet port.

Images