Switching valve

Abstract

To provide a switching valve capable of driving a valve body by means of a small torque.　The switching valve comprises: a communication passage 61 that connects a high pressure space 13 outside a passage 26 of a valve body 20 in a housing 10 with a low pressure space Pe having a lower pressure than the high pressure space 13; and an auxiliary valve 62 capable of opening and closing the communication passage 61.

Description

Switching valve

[0001] The present invention relates to a switching valve, for example, a switching valve that opens and closes a flow path through which a refrigerant flows or switches the flow path.

[0002] In various industrial fields, refrigerant circuits are used in which a refrigerant supply source is connected to a refrigerant load such as a refrigerant-operated device or a heat exchanger by a flow path. Some of these refrigerant circuits are provided with a switching valve for opening and closing the flow path or for switching the flow path.

[0003] For example, the switching valve of Patent Document 1 is mainly composed of a casing, a slider, and a spring. The casing is connected to a discharge pipe through which refrigerant discharged from the compressor flows, and a suction pipe through which refrigerant drawn into the compressor flows. The casing also has two ports formed in addition to the ports connected to the discharge pipe and the suction pipe. The slider is disposed within the casing and is rotatable. The spring is disposed between the valve seat and the slider in the casing.

[0004] Because the pressure difference between the inside and outside of the slider is large when the compressor is operating, the slider is pressed tightly against the valve seat against the biasing force of the spring, thereby dividing the flow path between one of the two ports and the port connected to the discharge pipe, and the other of the two ports and the port connected to the suction pipe.

[0005] Furthermore, when the compressor is stopped, the pressure difference between the inside and outside of the slider is small, so the slider is pushed away from the valve seat by the spring, preventing large frictional forces from occurring between the slider and the valve seat when the slider rotates.

[0006] Japanese Patent Application Laid-Open No. 62-288780 (page 4, Figure 1)

[0007] In the switching valve of Patent Document 1, the slider and the valve seat are moved toward and away from each other by changing the pressure acting on the slider. Therefore, when the slider is switched from a state in which it is seated on the valve seat at a certain rotational position to another rotational position, the pressure difference between the inside and outside of the slider is large, and there is a risk that a large torque will be required at the initial stage of switching.

[0008] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a switching valve capable of driving a valve element with a small torque.

[0009] In order to solve the above problems, the present invention provides a switching valve comprising: a housing; and a valve element rotatably mounted within the housing, the housing having an inlet port for introducing fluid into the housing, an outlet port for discharging fluid from the housing, and a plurality of other ports for introducing fluid into or discharging fluid from the housing, the valve element having passages for connecting at least two of the plurality of ports, and the valve element rotating within the housing to change the combination of the inlet port and the plurality of other ports and the outlet port and the plurality of other ports, the switching valve further comprising: a communicating passage for communicating a high-pressure space outside the passage of the valve element with a low-pressure space having a lower pressure than the high-pressure space within the housing, and an auxiliary valve for opening and closing the communicating passage. In this configuration, opening the communicating passage with the auxiliary valve connects the high-pressure space outside the passage with the other low-pressure space, thereby quickly equalizing the pressures, and therefore the valve element can be driven with a small torque when switching the rotational position of the valve element.

[0010] The low-pressure space may be an outflow port of the valve body. In this case, the low-pressure space connected to the passage communicates with the high-pressure space outside the passage, so that the pressure inside and outside the valve body can be quickly equalized.

[0011] The valve element and the auxiliary valve may be operable separately, and the auxiliary valve may operate prior to the operation of the valve element, so that the valve element can be driven after the pressure inside and outside the valve element is equalized.

[0012] The opening of the communication passage on the side of the high pressure space may be provided outside the range of movement of the valve body, thereby making it possible to prevent the communication passage from being blocked during the rotation of the valve body.

[0013] The opening of the communication passage on the side of the high-pressure space may be provided on a surface of the housing facing a valve seat. With this, the opening of the communication passage is provided on the surface of the housing facing the valve seat where the port is provided, so that refrigerant flowing from the high-pressure space to the port and refrigerant flowing from the high-pressure space to the communication passage are less likely to interfere with each other.

[0014] The passage of the valve element may always be in communication with one of the ports, and the communication passage may connect the one port to the high-pressure space. In this way, regardless of the rotational position of the valve element, the communication state between the high-pressure space outside the passage and the other low-pressure space can be switched by one communication passage and one auxiliary valve.

[0015] The auxiliary valve may be a solenoid valve, which allows the open / closed state of the communication passage to be controlled with high precision.

[0016] 1 is a schematic diagram showing a refrigerant circuit to which a switching valve of an embodiment according to the present invention is applied; FIG. 2 is a perspective view of a switching valve of an embodiment; FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2 in a state in which the gap between the valve body and the housing is sealed in an embodiment; FIG. 4 is a cross-sectional view taken along line A-A of FIG. 2 in a state in which the valve body is raised in an embodiment; FIG. 5 is a top view showing the valve body rotated from a first rotation position to a second rotation position in an embodiment; FIG. 6 is a schematic cross-sectional view (see cross-section B-B of FIG. 2) showing a closed state of a communication passage in an embodiment; FIG. 7 is a schematic cross-sectional view (see cross-section B-B of FIG. 2) showing a closed state of a communication passage in an embodiment;

[0017] 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.

[0018] A switching valve according to an embodiment will be described with reference to FIGS. 1 to 7. In the following description, the top and bottom of FIG. 3 will be taken as the top and bottom of the switching valve.

[0019] 1, a switching valve V of the present invention is a four-way valve provided in a refrigerant circuit 1. In addition to the switching valve V, the refrigerant circuit 1 is provided with a compressor C, a first load L1, and a second load L2. The compressor C discharges a discharge fluid Pd, which is a compressed high-pressure refrigerant, and draws a suction fluid Ps, which is a reduced-pressure low-pressure refrigerant.

[0020] The switching valve V is provided with an inlet port Pi as an inlet passage connected to the discharge side of the compressor C through a discharge passage 2, a first port P1 connected to a first load L1 through a first passage 3, a second port P2 connected to a second load L2 through a second passage 4, and an outlet port Pe as a port connected to the suction side of the compressor C through an outlet passage 5. The first load L1 and the second load L2 are connected through a third passage 6.

[0021] The switching valve V switches between passing the discharge fluid Pd from the compressor C through the first load L1 and then the second load L2 as shown by the solid line, and passing the discharge fluid Pd through the second load L2 and then the first load L1 as shown by the dashed line. The switching valve V will be described in detail below.

[0022] 2 and 3, the switching valve V is mainly composed of a housing 10, a valve element 20, a spring means 30 (see FIG. 3), a drive source 40 (see FIG. 2), and a pressure release means 60 (see FIG. 6). The pressure release means 60 will be described in detail later.

[0023] 2 and 3, the valve body 20 is in the first rotation position, communicating the inlet port Pi with the first port P1 (see FIG. 2) and communicating the second port P2 (see FIG. 3) with the outlet port Pe (see FIG. 3).

[0024] The housing 10 is mainly composed of a case 11 and a stator 12 .

[0025] 2, the case 11 is made of resin and includes a main body 11a and a socket 11b. The case 11 may be made of metal, and the material may be changed as appropriate.

[0026] The main body 11a is a cylindrical body with a ceiling that opens downward, and includes a stepped plate-like ceiling that is D-shaped when viewed from above, and a peripheral wall that extends downward from the periphery of the ceiling.

[0027] An inlet port Pi is formed in the ceiling of the main body 11a, penetrating in the vertical direction.

[0028] A support hole 11c (see FIG. 3) is formed in the ceiling of the main body 11a, recessed upward from the lower end surface thereof. A support shaft 14 is inserted and fixed into this support hole 11c.

[0029] The socket 11b is cylindrical and has a bottom, and protrudes outward from the peripheral wall of the main body 11a. The drive source 40 is inserted into and fixed in the socket 11b. The space between the socket 11b and the drive source 40 is sealed with packing.

[0030] A through-hole 11d is formed in the peripheral wall of the main body 11a and in the bottom of the socket 11b, penetrating the socket 11b in the axial direction. A rod 41 (described later) is inserted through this through-hole 11d and positioned in the valve chamber 13.

[0031] 2 and 3, a first port P1 (see FIG. 2), a second port P2 (see FIG. 3), and an outlet port Pe (see FIG. 3) are formed in the stator 12. The first port P1, the second port P2, and the outlet port Pe all pass through the stator 12 in the vertical direction.

[0032] The first port P1, the second port P2, and the outlet port Pe are formed to be located at the vertices of an isosceles triangle when the stator 12 is viewed from above (see FIG. 5). The distance between the first port P1 and the outlet port Pe is substantially the same as the distance between the second port P2 and the outlet port Pe.

[0033] Referring to Figure 3, the main body 11a and the stator 12 are fastened together with bolts (not shown). The stator 12 has a groove 12c formed along its edge, recessed downward from the upper end surface. The main body 11a is pressed against a packing 18 disposed in the groove 12c. A seal is formed between the main body 11a and the stator 12. The main body 11a and the stator 12 form a valve chamber 13.

[0034] The stator 12 also has a groove 12d formed to fit along a leg 27 (described later) of the valve element 20 stopped at the first rotation position and the leg 27 of the valve element 20 stopped at the second rotation position. The groove 12d is recessed downward from the upper surface 12a of the stator 12. A packing 15 serving as a valve seat is disposed in the groove 12d. The upper surface 12a of the stator 12 functions as the surface of the housing 10 facing the valve seat.

[0035] The valve body 20 is made of resin and has a cylindrical portion 21 that is circular in top view and a dome portion 22 that is elliptical in top view. The valve body 20 may be made of metal, and the material may be changed as appropriate.

[0036] The cylindrical portion 21 has a bottomed cylindrical shape and extends in the vertical direction. A bush 16 is disposed on the inner diameter side of the cylindrical portion 21, and the support shaft 14 is inserted into the bush 16.

[0037] The dome portion 22 is provided below and connected to the cylindrical portion 21. A passage 26 is formed inside the dome portion 22. More specifically, the passage 26 is defined by the inner surface of the dome portion 22 and the upper surface of the stator 12. An annular leg portion 27 is formed at the lower end of the dome portion 22 and continues along the edges of these portions.

[0038] The support shaft 14 is disposed on the axis Ax of the outlet port Pe. The valve element 20 is movable in the axial direction along the support shaft 14 and is rotatable around the support shaft 14.

[0039] 3 and 4, a recess 17 is formed above the outlet port Pe of the stator 12. A spring means 30 is disposed in this recess 17. The spring means 30 applies a spring force to the valve body 20 upward, i.e., in a direction that causes the valve body 20 to float up from the packing 15.

[0040] As shown in FIG. 3 , the valve element 20 stopped at the first rotation position is pushed down by the pressure of the discharge fluid Pd flowing into the valve chamber 13 from the inlet port Pi, and the leg portion 27 is pressed against the packing 15 .

[0041] As a result, the switching valve V separates the passage 26 from the space outside the valve body 20, i.e., the space outside the passage 26 within the valve chamber 13 (hereinafter simply referred to as the valve chamber 13), and connects the inlet port Pi to the first port P1, and the second port P2 to the outlet port Pe.

[0042] On the other hand, the smaller the difference between the pressure in the valve chamber 13 and the pressure in the passage 26, the smaller the force moving the valve element 20 toward the stator 12. When this force falls below the biasing force of the elastic means 30, the valve element 20 moves from the state shown in Figure 3 in response to the extension of the elastic means 30, and separates from the packing 15, i.e., floats up, as shown in Figure 4.

[0043] In this way, by rotating the valve element 20 to the second rotation position in a floating state, it is possible to reduce the generation of a large frictional force between the valve element 20 and the packing 15. The rotation of the valve element 20 will be described below.

[0044] The valve element 20 may rise upward due to the biasing force of the spring means 30, vibration, or the like. In this case, the bottom surface 21a of the cylindrical portion 21 abuts against the bottom surface 14a of the support shaft 14, preventing the valve element 20 from rising any further. The position where the bottom surface 21a of the cylindrical portion 21 abuts against the bottom surface 14a of the support shaft 14 is called the upper limit of movable position of the valve element 20. When the valve element 20 is in the upper limit of movable position, the valve element 20 does not come into contact with the rod 41 of the drive source 40. This prevents deformation of the rod 41 and the generation of wear debris due to contact between the valve element 20 and the rod 41, and prevents malfunction of the rod 41.

[0045] First, the driving source 40 and the cylindrical portion 21 of the valve body 20 will be described.

[0046] The drive source 40 is a solenoid that, when energized, advances the rod 41 toward the valve chamber 13. The drive source 40 also has a spring (not shown), and when energization is stopped, the urging force of the spring causes the rod 41 to retract toward the drive source 40. Note that the drive source may be configured to retract the rod when energized and advance the rod by the force of the spring when de-energized.

[0047] As shown in Fig. 5, the rod 41 is a cylindrical body having a first ridge portion 42, a small-diameter shaft portion 43, and a second ridge portion 44. Fig. 5 illustrates a state in which the valve body 20 has been moved from a first rotation position indicated by a two-dot chain line to a second rotation position indicated by a solid line.

[0048] A recess 50, a long thick portion 51, and a short thick portion 52 are formed on the outer periphery of the cylindrical portion 21. The long thick portion 51 has a half arc shape when viewed from above, and the short thick portion 52 has a one-eighth arc shape when viewed from above.

[0049] When the valve body 20 is rotated from the first rotation position to the second rotation position, the valve body 20 is first floated as described above.

[0050] When the rod 41 advances, the first convex portion 42 comes into contact with the long thick portion 51. The long thick portion 51 is pressed by the advancing rod 41, and rotates clockwise as the advance distance of the rod 41 increases.

[0051] As the rod 41 advances further, the first convex portion 42 and the long thick portion 51 move apart, and the second convex portion 44 comes into contact with the short thick portion 52. The short thick portion 52 is pressed by the advancing rod 41 and rotates clockwise as the advancement distance of the rod 41 increases.

[0052] Furthermore, the valve element 20, which is integral with the cylindrical portion 21, also rotates clockwise integrally with the cylindrical portion 21. During this time, the leg portion 27 of the valve element 20 slides along the upper end of the spring means 30, but the valve element 20 is placed on the spring means 30, and the frictional force generated between the leg portion 27 at the lower end of the valve element 20 and the upper surface 12a of the stator 12 or the packing 15 is reduced.

[0053] Thereafter, the rod 41 advances a predetermined distance, and the valve body 20 stops at the second rotation position.

[0054] The valve element 20 stopped at the second rotation position is pressed against the packing 15 by the pressure of the discharge fluid Pd, just as when it is stopped at the first rotation position. As a result, the switching valve V separates the passage 26 from the space outside the valve element 20 in the valve chamber 13, and communicates the inlet port Pi with the second port P2 and the first port P1 with the outlet port Pe.

[0055] When the valve body 20 is rotated from the second rotation position to the first rotation position, the valve body 20 is floated in the same manner as when the valve body 20 is stopped at the first rotation position.

[0056] When the power supply to the drive source 40 is stopped and the rod 41 is retracted by a spring (not shown), the first convex portion 42 comes into contact with the short thick portion 52 .

[0057] The shorter thicker portion 52 is pressed by the retracting rod 41 and rotates counterclockwise as the retracting distance of the rod 41 increases.

[0058] Furthermore, the valve element 20, which is integral with the cylindrical portion 21, also rotates counterclockwise together with the cylindrical portion 21.

[0059] Thereafter, as shown by the two-dot chain line in FIG. 5, the rod 41 moves back a predetermined distance, that is, stops at the position where it has moved back the most, and the valve body 20 stops at the first rotation position.

[0060] Next, the pressure release means 60 will be described with reference to Figures 6 and 7. Figures 6 and 7 show the valve body 20 in the first rotation position. Furthermore, Figures 6 and 7 omit the configuration of the socket 11b and the drive source 40.

[0061] As shown in FIGS. 6 and 7, the pressure relief means 60 is mainly composed of a communication passage 61 and an auxiliary valve 62.

[0062] The communicating passage 61 has a portion 61A of the stator 12 which is a through hole extending substantially horizontally from the outlet port Pe, a portion 61B of the stator 12 which is a through hole extending substantially vertically from the upper surface 12a of the stator 12 which serves as the valve seat side surface, and a portion 61C of the stator 12 which is a through hole where the portions 61A and 61B intersect. The portion 61C is a hole with a larger diameter than the portions 61A and 61B, and one end thereof communicates with the outer diameter side of the stator 12.

[0063] That is, the communication passage 61 communicates between the valve chamber 13 as a high-pressure space outside the passage 26 and the outflow port Pe as another low-pressure space, and is generally L-shaped in cross section.

[0064] The auxiliary valve 62 is an electromagnetic valve mainly composed of a fixed iron core 621 having an approximately cylindrical shape, a rod 622 inserted into the fixed iron core 621 and capable of reciprocating in the axial direction, a valve body 623 fixed to one end of the rod 622, a movable iron core 624 fixed to the other end of the rod 622, a coil spring 625 provided between the fixed iron core 621 and the movable iron core 624 for biasing the movable iron core 624 in a direction away from the fixed iron core 621, and an excitation coil 626 wound around the outside of the fixed iron core 621 via a bobbin.

[0065] The auxiliary valve 62 is fixed to the stator 12 in a sealed manner so as to close the portion 61C of the communication passage 61 from the outer diameter side. At this time, the valve body 623 is disposed within the portion 61C of the communication passage 61. From the viewpoint of sealing performance, the valve body 623 is preferably a sealing member made of rubber or the like.

[0066] 6, when the auxiliary valve 62 is energized, the movable iron core 624 is attracted to the fixed iron core 621 against the biasing force of the coil spring 625, and the rod 622 and the valve body 623 move together to the right side of the drawing. As a result, the valve body 623 comes into close contact with the opening periphery 12b, which is the valve seat of the portion 61A of the communicating passage 61 in the stator 12. In other words, the communicating passage 61 is in a closed state.

[0067] 7, when the auxiliary valve 62 is not energized, the biasing force of the coil spring 625 moves the movable core 624 in a direction away from the fixed core 621, and the rod 622 and the valve body 623 move together to the left side of the drawing. As a result, the valve body 623 moves away from the opening periphery 12b of the portion 61A of the communicating passage 61 in the stator 12. In other words, the communicating passage 61 is in an open state.

[0068] When the compressor C is operating and the valve element 20 is in the first or second rotation position, the auxiliary valve 62 is energized to close the communication passage 61 (see FIG. 6 ). This keeps the pressure in the valve chamber 13 higher than the pressure in the passage 26, ensuring a tight seal between the valve chamber 13 and the passage 26.

[0069] When moving the valve element 20 from the state shown in Figure 6 to either the first rotation position or the second rotation position, first, the auxiliary valve 62 is de-energized to open the communication passage 61 (see Figure 7). This quickly equalizes the pressure in the valve chamber 13 and the pressure in the passage 26. Then, the valve element 20 is rotated. This allows the valve element 20 to be driven with a small torque when switching the rotation position of the valve element 20.

[0070] When the rotational position of the valve element 20 is switched, the compressor C may be stopped or may be in a driven state. When the compressor C is stopped, the auxiliary valve 62 is de-energized and the communication passage 61 is opened, so that no load is applied to the valve element 20 or the refrigerant circuit 1.

[0071] Furthermore, the communication passage 61 communicates the high-pressure valve chamber 13 with the low-pressure passage 26, thereby equalizing the pressure inside the valve chamber 13 and the pressure inside the passage 26. When the high-pressure valve chamber 13 is communicated with another low-pressure space, the pressure inside the valve chamber 13 decreases, but it takes time for the pressure inside the valve chamber 13 and the passage 26 to be equalized.

[0072] Furthermore, the valve element 20 is driven by the drive source 40 and rod 41, and the valve element 623 of the auxiliary valve 62 is driven by a solenoid unit consisting of a fixed iron core 621, a movable iron core 624, and a coil 626, as well as by a rod 622 and a coil spring 625. When switching the rotational position of the valve element 20, the valve element 623 is first operated in the valve opening direction and then the valve element 20 is rotated, so that after the pressures in the valve chamber 13 and the passage 26 are equalized, the valve element 20 can be reliably driven with a small torque.

[0073] Furthermore, the opening 61Ba (see FIG. 5) of the communication passage 61 on the valve chamber 13 side is provided outside the range of movement of the valve element 20, which prevents the communication passage 61 from being blocked during rotation of the valve element 20. This allows the pressure in the valve chamber 13 and the passage 26 to be equalized regardless of the rotational position of the valve element 20.

[0074] Furthermore, the opening 61Ba of the communication passage 61 on the valve chamber 13 side is provided on the upper surface 12a of the stator 12. With this, the opening 61Ba faces the same direction as the first port P1, the second port P2, and the outflow port Pe, i.e., the up-down direction, and therefore, the refrigerant flowing from the valve chamber 13 to the first port P1, the second port P2, and the outflow port Pe and the refrigerant flowing from the valve chamber 13 to the communication passage 61 are less likely to interfere with each other.

[0075] Furthermore, since the communication passage 61 is connected to the outflow port Pe, which is always connected to the passage 26 of the valve body 20, it is possible to switch between the valve chamber 13 and the passage 26 using a single pressure release means 60 regardless of the rotational position of the valve body 20.

[0076] Furthermore, since the auxiliary valve 62 is an electromagnetic valve, it has good responsiveness and can accurately control the open / closed state of the communication passage 61 .

[0077] In the present embodiment, the auxiliary valve 62 is exemplified as having a configuration in which the rod 622 advances when energized to close the communication passage 61, and the rod 622 retreats by the force of the coil spring 625 when not energized to open the communication passage 61, but it may also be configured such that the rod retreats by the force of the coil spring when energized to open the communication passage, and the rod advances when energized to close the communication passage.

[0078] 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.

[0079] For example, in the above embodiment, the communicating passage 61 is shown as connecting the valve chamber 13 and the outflow port Pe, but the communicating passage may also connect a high-pressure space outside the passage with a low-pressure space not connected to the passage.

[0080] In the above embodiment, the valve chamber 13 is described as a high-pressure space and the outlet port Pe as a low-pressure space, but the arrangement of the high-pressure space and the low-pressure space may be reversed. From the viewpoint of sealing when the valve element is stopped, it is preferable that the space on the back side of the valve element be the high-pressure space.

[0081] In addition, in the above embodiment, the opening 61Ba on the valve chamber 13 side of the communicating passage 61 is provided on the upper surface 12a of the stator 12, but it may also be provided on, for example, the side wall or ceiling portion of the housing.

[0082] Furthermore, in the above embodiment, one communication passage 61 and one auxiliary valve 62 are provided, but a plurality of communication passages and a plurality of auxiliary valves may be provided.

[0083] In the above embodiment, the auxiliary valve 62 is an electromagnetic valve, but the present invention is not limited to this and may be manually operated or motorized, or may be modified as appropriate.

[0084] In the above embodiment, the valve element rotates between the first rotation position and the second rotation position, but the valve element may have three or more rotation positions.

[0085] In the above embodiment, the driving source is a solenoid, but this is not limiting and may be a manual drive source, a motor drive source, or any other suitable drive source. Furthermore, the solenoid may be a self-holding type.

[0086] In addition, in the above embodiment, the valve element is rotated by utilizing the axial movement of the rod, which is described as a so-called rack and pinion configuration, but this is not limited to this, and the valve element may be rotated by a motor, and the drive means for rotating the valve element may be changed as appropriate.

[0087] In addition, in the above embodiment, the switching valve is described as a four-way valve, but this is not limited to this, and the number of ports may be changed as appropriate, or it may be an opening / closing valve that opens and closes between the inlet and outlet paths.

[0088] In the above embodiment, the packing that seals the gap between the valve disc and the stator is described as being located on the stator side, but this is not limited thereto; the packing may be located on the valve disc side. Even with this configuration, the packing floats together with the valve disc, separating it from the stator or reducing the contact area, thereby reducing the frictional force generated between the valve disc and the stator. In this case, the portion of the stator with which the packing contacts functions as the valve seat. In other words, the member on the stator side that contacts the member on the valve disc side functions as the valve seat.

[0089] REFRIGERATION PATH 10 HOUSING 12 STATOR 12a UPPER SURFACE (SURFACE ON THE VALVE SEAT SIDE) 13 VALVE CHAMBER (SPACE OUTSIDE THE PASSAGE, HIGH-PRESSURE SPACE) 15 GASKETS (VALVE SEAT) 20 VALVE DISC 21 CYLINDER 22 DOME 26 PASSAGE 27 LEGS 30 RESILIENT MEANS 60 PRESSURE RELEASE MEANS 61 COMMUNICATION PASS 61Ba OPENING 62 AUXILIARY VALVE 623 VALVE DISC Pe OUTLET PORT (ANOTHER SPACE, LOW-PRESSURE SPACE) V SWITCHING VALVE

Claims

1. A switching valve comprising a housing and a valve element rotatably mounted within the housing, wherein the housing is formed with an inlet port for introducing fluid into the housing, an outlet port for discharging fluid from the housing, and a plurality of other ports for introducing fluid into or discharging fluid from the housing, the valve element having passages capable of connecting at least two of the plurality of ports, and wherein the combination of the inlet port and the plurality of other ports and the outlet port and the plurality of other ports can be changed by the valve element rotating within the housing, the switching valve comprising a communicating passage connecting a high-pressure space outside the passage of the valve element within the housing with a low-pressure space having a lower pressure than the high-pressure space, and an auxiliary valve capable of opening and closing the communicating passage.

2. A switching valve according to claim 1, wherein the low-pressure space is the outlet port of the valve body.

3. A switching valve as claimed in claim 1, wherein the valve body and the auxiliary valve are operable separately, and the auxiliary valve operates prior to the operation of the valve body.

4. A switching valve according to claim 1, wherein the opening of the communication passage on the side of the high-pressure space is provided outside the range of movement of the valve element.

5. A switching valve according to claim 1, wherein the opening of the communication passage on the side of the high-pressure space is provided on a surface of the housing on the side of the valve seat.

6. A switching valve as set forth in claim 1, wherein the passage of said valve element is always in communication with one of said ports, and said communication passage connects said one port with said high-pressure space.

7. A switching valve according to any one of claims 1 to 6, wherein the auxiliary valve is a solenoid valve.

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