Flow passage switching system

Abstract

To provide a flow passage switching system that can switch between flow passages by using upstream and downstream pressures of a pump while restraining a decrease in pump efficiency.SOLUTION: A flow passage switching device 1 according to an embodiment of the present disclosure operates a diaphragm 24 to drive a drive shaft 25, and thereby opens and closes a first discharge flow passage 22-1 and a second discharge flow passage 22-2 by a valve element 26 to switch between the flow passages. The flow passage switching device comprises a first communication passage 41 for establishing communication between a back pressure chamber 31 and a pump upstream flow passage 71, a second communication passage 42 for establishing communication between the back pressure chamber 31 and a pump downstream flow passage 72, and a pilot valve 51 for switching between communication states of the first communication passage 41 and a second communication passage 42.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a flow path switching system that switches a flow path of a fluid (for example, cooling water). [Background technology]

[0002] Patent Document 1 discloses a flow path structure in which a fluid (heat medium) sent by a pump is supplied to a heater core while being controlled by a main valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-82950 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not disclose anything about the pump efficiency (i.e., the ratio of the pump's output to its input). If the main valve were a three-way valve that switches between two flow paths, the pump efficiency could decrease depending on the flow path that is switched.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a flow path switching system that can switch flow paths by utilizing the pressure before and after the pump while suppressing a decrease in pump efficiency. [Means for solving the problem]

[0006] One form of the present disclosure made to solve the above problems includes a flow path switching valve unit and a pump that sends a fluid to the flow path switching valve unit, the flow path switching valve unit including an inlet flow path that introduces the fluid sent by the pump, a first outlet flow path and a second outlet flow path that branch off from the inlet flow path and discharge the fluid, a movable wall chamber, a movable wall disposed within the movable wall chamber, a drive shaft connected to the movable wall, and a valve body provided on the drive shaft, and the flow path switching system switches flow paths by operating the movable wall to drive the drive shaft to open and close the first outlet flow path and the second outlet flow path with the valve body, the flow path switching system including a first communication passage that connects the movable wall chamber to an upstream flow path of the pump, a second communication passage that connects the movable wall chamber to a downstream flow path of the pump, and a communication state switching valve that switches a communication state between the first communication passage and the second communication passage.

[0007] According to this aspect, the communication state of the first communication passage and the second communication passage (i.e., the communication state between the movable wall chamber and the upstream and downstream flow passages of the pump by the first and second communication passages) can be switched by the communication state switching valve, so that the movable wall can be freely operated using the pressures at the front and rear of the pump (i.e., the pressures at the upstream and downstream sides).Then, the pressures at the front and rear of the pump are used to move the movable wall and drive the drive shaft, so that the first outlet flow passage and the second outlet flow passage can be opened and closed by the valve body, thereby switching the flow passages.

[0008] At this time, the pressure before and after the pump can be transmitted to the movable wall chamber when there is no fluid flow in the first communication passage or the second communication passage. This makes it possible to suppress a decrease in the pump efficiency of the pump that sends fluid to the flow passage switching valve unit. Therefore, the flow passage can be switched by utilizing the pressure before and after the pump while suppressing a decrease in the pump efficiency.

[0009] In the above aspect, it is preferable that the movable wall chamber includes a back pressure chamber partitioned by the movable wall, and the communication state switching valve is switched to either a state in which the back pressure chamber is connected to an upstream flow path of the pump via the first communication passage, or a state in which the back pressure chamber is connected to a downstream flow path of the pump via the second communication passage.

[0010] According to this aspect, the flow passages can be switched by utilizing the pressure before and after the pump with a simple configuration, and therefore the manufacturing costs of the flow passage switching system can be reduced.

[0011] In the above aspect, it is preferable that the movable wall chamber includes a back pressure chamber and an intermediate chamber separated from the back pressure chamber by the movable wall, the first communication passage is a passage connecting the back pressure chamber with an upstream flow path of the pump, the second communication passage is a passage connecting the intermediate chamber with a downstream flow path of the pump, and an intermediate passage is provided as a passage connecting the first communication passage with the second communication passage, and the communication state changeover valve is switched to either a state where the first communication passage and the second communication passage are connected via the intermediate passage to connect both the back pressure chamber and the intermediate chamber with the upstream flow path of the pump, or a state where the back pressure chamber is connected with the upstream flow path of the pump via the first communication passage and the intermediate chamber is connected with the downstream flow path of the pump via the second communication passage.

[0012] According to this aspect, it is possible to adjust the pressure in the intermediate chamber in addition to the back pressure chamber, and the responsiveness of the operation of the valve body can be improved, thereby improving the responsiveness of the switching of the flow path.

[0013] In the above aspect, it is preferable that the movable wall chamber includes a back pressure chamber and an intermediate chamber separated from the back pressure chamber by the movable wall, the first communication passage is a passage connecting the back pressure chamber with an upstream flow path of the pump, the second communication passage is a passage connecting the intermediate chamber with a downstream flow path of the pump, and an intermediate passage is provided as a passage connecting the first communication passage with the second communication passage, and the communication state changeover valve is switched to either a state in which the first communication passage is connected to the second communication passage via the intermediate passage, thereby connecting both the back pressure chamber and the intermediate chamber with both the upstream flow path of the pump and the downstream flow path of the pump, respectively, or a state in which the back pressure chamber is connected to the upstream flow path of the pump via the first communication passage and the intermediate chamber is connected to the downstream flow path of the pump via the second communication passage.

[0014] According to this aspect, it is possible to adjust the pressure in the intermediate chamber in addition to the back pressure chamber, and the responsiveness of the operation of the valve body can be improved, thereby improving the responsiveness of the switching of the flow path.

[0015] In the above aspect, the movable wall is preferably a diaphragm.

[0016] According to this aspect, since a diaphragm that is relatively inexpensive is used, the manufacturing cost of the flow passage switching system can be suppressed.

[0017] In the above aspect, it is preferable that the flow path switching system is a flow path switching device in which the flow path switching valve unit and the pump are integrally formed.

[0018] According to this aspect, by configuring the pump as the drive unit for the flow path switching valve unit, a compact and low-cost flow path switching device can be obtained.

[0019] In the above aspect, it is preferable that the flow path switching system is mounted on a flow path of cooling water for an electric vehicle.

[0020] According to this aspect, the flow path switching system can efficiently control the flow of cooling water for the electric vehicle, thereby improving the energy efficiency of the electric vehicle and contributing to carbon neutrality. Effect of the Invention

[0021] According to the flow path switching system of the present disclosure, it is possible to switch flow paths by utilizing the pressure before and after the pump while suppressing a decrease in pump efficiency. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a front view of the flow path switching device according to the first embodiment. [Diagram 2] FIG. 1 is a perspective view of a flow path switching device according to a first embodiment. [Diagram 3] 1 is a cross-sectional view (partial external view) of a flow path switching device according to a first embodiment. [Figure 4] FIG. 11 is a diagram showing an upstream flow maintained state (a state in which the upstream flow is maintained) in the first embodiment. [Diagram 5] FIG. 11 is a diagram showing a switching state to a downstream flow (a switching state from an upstream flow to a downstream flow) in the first embodiment. [Figure 6] FIG. 2 is a diagram showing a downstream flow maintained state (a state in which the downstream flow is maintained) in the first embodiment. [Figure 7] FIG. 11 is a diagram showing a switching state to an upstream flow (a switching state from a downstream flow to an upstream flow) in the first embodiment. [Figure 8] FIG. 13 is a diagram showing an upstream flow holding state in the first example of the second embodiment. [Figure 9] FIG. 13 is a diagram showing a state of switching to a downstream flow in a first example of the second embodiment. [Figure 10] FIG. 13 is a diagram showing a downstream flow holding state in the first example of the second embodiment. [Figure 11] FIG. 13 is a diagram showing a state of switching to an upstream flow in a first example of the second embodiment. [Figure 12] FIG. 13 is a diagram showing an upstream flow holding state in a second example of the second embodiment. [Figure 13] FIG. 13 is a diagram showing an initial state at the start of switching to downstream flow (a state in which switching from upstream flow to downstream flow begins) in a second example of the second embodiment. [Figure 14] FIG. 13 is a diagram showing a valve open state for switching to downstream flow (a state in which the valve is about to open to switch from upstream flow to downstream flow) in a second example of the second embodiment. [Figure 15] FIG. 13 is a diagram showing a state in the middle of switching to a downstream flow (a state in the middle of switching from an upstream flow to a downstream flow) in a second example of the second embodiment. [Figure 16] FIG. 13 is a diagram showing a downstream flow holding state in a second example of the second embodiment. [Figure 17] FIG. 13 is a diagram showing an initial state at the start of switching to upstream flow (a state in which switching starts from downstream flow to upstream flow) in a second example of the second embodiment. [Figure 18] FIG. 13 is a diagram showing a valve open state for switching to upstream flow (a state in which the valve is about to open to switch from downstream flow to upstream flow) in a second example of the second embodiment. [Figure 19] FIG. 13 is a diagram showing a state in the middle of switching to an upstream flow (a state in the middle of switching from a downstream flow to an upstream flow) in a second example of the second embodiment.

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flow path switching system according to the present disclosure will be described below. In the following description, a flow path switching device, which is an example of an embodiment of a flow path switching system according to the present disclosure, will be described.

[0024] First Embodiment First, a flow path switching device 1 according to a first embodiment will be described.

[0025] The flow path switching device 1 is, for example, a device mounted in a flow path of cooling water of an electric vehicle (not shown) and controls the flow rate of the cooling water. Note that an "electric vehicle" is, for example, a vehicle that is driven by power from a secondary battery as the driving source of the vehicle, such as an electric vehicle or a hybrid vehicle. The cooling water is an example of the "fluid" in the present disclosure.

[0026] (Configuration of flow path switching device) 1 to 3, the flow path switching device 1 has a flow path switching valve unit 11, a pump 12, and a control unit 13, and the flow path switching valve unit 11, the pump 12, and the control unit 13 are integrally formed as a single device. Note that the control unit 13 may be provided separately from the flow path switching device 1. For ease of explanation, the control unit 13 is shown only in FIG. 1, and is omitted in FIG. 2 and subsequent drawings.

[0027] The flow path switching valve unit 11 is a valve unit that switches the flow paths. The flow path switching valve unit 11 includes an inlet flow path 21 that introduces the cooling water fed by the pump 12, and a first outlet flow path 22-1 and a second outlet flow path 22-2 that branch off from the inlet flow path 21 and discharge the cooling water.

[0028] The flow path switching valve section 11 also includes a diaphragm chamber 23, a diaphragm 24 arranged in the diaphragm chamber 23, a drive shaft 25 connected to the diaphragm 24, a valve body 26 provided at one end of the drive shaft 25, a first valve seat 27-1, and a second valve seat 27-2.

[0029] The diaphragm chamber 23 includes a back pressure chamber 31 that is partitioned by the diaphragm 24. The back pressure chamber 31 is provided with a spring 33 that urges the diaphragm 24 downward (downward in FIG. 4). In this embodiment, a portion of the diaphragm chamber 23 on the opposite side of the diaphragm 24 from the back pressure chamber 31 (a portion corresponding to an intermediate chamber 32 described below) is open to the first outlet flow path 22-1. The diaphragm chamber 23, the back pressure chamber 31, and the intermediate chamber 32 described below are examples of the "movable wall chamber" in the present disclosure, and the diaphragm 24 is an example of the "movable wall" in the present disclosure.

[0030] The pump 12 is a device that sends cooling water to the flow path switching valve unit 11.

[0031] The control unit 13 is a device that controls the flow path switching device 1. The control unit 13 controls, for example, the pump 12 and a pilot valve 51 and a pilot valve 91, which will be described later.

[0032] In this embodiment, as shown in FIGS. 1 to 4, the flow path switching device 1 has a first communication passage 41, a second communication passage 42, and a pilot valve 51.

[0033] The first communication passage 41 is formed by the pressure transmission passage 60 and the first branch passage 61, and is a passage that can communicate between the back pressure chamber 31 and the pump upstream flow passage 71. The pump upstream flow passage 71 is a flow passage provided upstream of the pump 12 in the flow direction of the cooling water, and is an example of the "upstream flow passage of the pump" in the present disclosure.

[0034] The second communication passage 42 is formed by the pressure transmission passage 60 and the second branch passage 62, and is a passage that can communicate between the back pressure chamber 31 and the pump downstream flow passage 72. The pump downstream flow passage 72 is a flow passage provided downstream of the pump 12 in the flow direction of the cooling water, and is an example of the "pump downstream flow passage" in the present disclosure.

[0035] The pilot valve 51 is a valve that switches the communication state between the first communication passage 41 and the second communication passage 42. That is, the pilot valve 51 can be switched to either a state in which the pressure transmission passage 60 communicates with the first branch passage 61 or a state in which the pressure transmission passage 60 communicates with the second branch passage 62. The pilot valve 51 is an example of a "communication state switching valve" in the present disclosure.

[0036] (Function of flow path switching device) The flow path switching device 1 configured as described above switches the flow paths by opening and closing the first outlet flow path 22-1 and the second outlet flow path 22-2 with the valve body 26 by operating the diaphragm 24 to drive the drive shaft 25. Specifically, the flow path switching device 1 uses the front and rear pressures of the pump 12 to adjust the pressure in the back pressure chamber 31 and operate the diaphragm 24.

[0037] In addition, the pilot valve 51 is switched to either a state in which the back pressure chamber 31 communicates with the pump upstream flow path 71 via the first communication passage 41, or a state in which the back pressure chamber 31 communicates with the pump downstream flow path 72 via the second communication passage 42.

[0038] A specific flow path switching will now be described. First, as shown in Fig. 4, the pilot valve 51 is in the OFF state, and the pressure transmission passage 60 and the first branch passage 61 are blocked, while the pressure transmission passage 60 and the second branch passage 62 are connected.

[0039] As a result, the back pressure chamber 31 communicates with the pump downstream flow path 72 via the second communication passage 42. Then, when there is no flow of cooling water in the second communication passage 42, the pressure of the pump downstream flow path 72 is transmitted to the back pressure chamber 31. In addition, the force of the spring 33 acts downward on the diaphragm 24.

[0040] Furthermore, since the valve element 26 is in contact with the second valve seat 27-2 and the valve hole of the first valve seat 27-1 (i.e., a hole provided on the inside of the first valve seat 27-1) is open, a flow path is formed by the inlet flow path 21 and the first outlet flow path 22-1, and the cooling water flows from the inlet flow path 21 to the first outlet flow path 22-1. Then, the pressure of the cooling water flowing from the inlet flow path 21 to the first outlet flow path 22-1 acts on the valve element 26 downward (i.e., in the direction of the second valve seat 27-2). In this way, the flow path switching device 1 is in an upstream flow holding state (i.e., a state in which the upstream flow (flow to the first outlet flow path 22-1) is held).

[0041] 4 and subsequent figures, the arrows indicate the forces acting, and pressure P0 is the pressure in the pump upstream flow path 71, pressure P1 is the pressure in the first outlet flow path 22-1, and pressure P2 is the pressure in the second outlet flow path 22-2. Furthermore, pressure P3 is the pressure in the pump downstream flow path 72 (inlet flow path 21), and pressure Pa is the pressure in the back pressure chamber 31.

[0042] Next, as shown in FIG. 5, when the pilot valve 51 is switched to the ON state, the pressure transmission passage 60 and the first branch passage 61 are communicated with each other, while the pressure transmission passage 60 and the second branch passage 62 are blocked from each other.

[0043] As a result, the back pressure chamber 31 communicates with the pump upstream flow path 71 through the first communication passage 41. The pressure Pa of the back pressure chamber 31 is higher than the pressure P0 of the pump upstream flow path 71. Therefore, the cooling water in the back pressure chamber 31 is discharged to the pump upstream flow path 71 through the first communication passage 41, so that the pressure Pa of the back pressure chamber 31 decreases and an upward force acts on the diaphragm 24.

[0044] Then, the diaphragm 24 moves upward to drive the drive shaft 25 upward, so that the valve body 26 separates from the second valve seat 27-2. In this way, the flow path switching device 1 is in a switching state to the downstream flow (a state in which the flow path switching device 1 switches from the upstream flow to the downstream flow).

[0045] Next, as shown in FIG. 6, when the pilot valve 51 is maintained in the ON state, the valve body 26 abuts against the first valve seat 27-1. As a result, the valve hole of the second valve seat 27-2 (i.e., a hole provided on the inside of the second valve seat 27-2) is opened, so that a flow path is formed by the inlet flow path 21 and the second outlet flow path 22-2, and the cooling water flows from the inlet flow path 21 to the second outlet flow path 22-2. Then, the pressure of the cooling water flowing from the inlet flow path 21 to the second outlet flow path 22-2 acts on the valve body 26 upward (i.e., in the direction of the first valve seat 27-1). In this way, the flow path switching device 1 is in a downstream flow holding state (a state in which the downstream flow (flow to the second outlet flow path 22-2) is held).

[0046] Next, as shown in FIG. 7, when the pilot valve 51 is switched to the OFF state, the pressure transmission passage 60 and the first branch passage 61 are blocked, while the pressure transmission passage 60 and the second branch passage 62 are communicated.

[0047] As a result, the back pressure chamber 31 communicates with the pump downstream flow path 72 through the second communication passage 42. The pressure Pa of the back pressure chamber 31 is lower than the pressure P3 of the pump downstream flow path 72. Therefore, the cooling water in the pump downstream flow path 72 flows into the back pressure chamber 31 through the second communication passage 42, so that the pressure Pa of the back pressure chamber 31 increases and a downward force acts on the diaphragm 24.

[0048] Then, the diaphragm 24 moves downward to drive the drive shaft 25 downward, so that the valve body 26 separates from the first valve seat 27-1. In this way, the flow path switching device 1 is in a switching state to the upstream flow (a state in which the flow path switching device 1 switches from the downstream flow to the upstream flow).

[0049] Thereafter, when the pilot valve 51 is maintained in the OFF state, the flow path switching device 1 again goes into the upstream flow holding state as shown in FIG.

[0050] (Effects of this embodiment) According to this embodiment, the flow path switching device 1 has a first communication passage 41 that communicates between the back pressure chamber 31 and the pump upstream flow path 71, and a second communication passage 42 that communicates between the back pressure chamber 31 and the pump downstream flow path 72. The flow path switching device 1 also has a pilot valve 51 that switches the communication state between the first communication passage 41 and the second communication passage 42.

[0051] As a result, by switching the communication state between the first communication passage 41 and the second communication passage 42 by the pilot valve 51, the diaphragm 24 can be freely operated by utilizing the pressures before and after the pump 12. Note that the communication state between the first communication passage 41 and the second communication passage 42 refers to a communication state between the back pressure chamber 31 and the pump upstream side flow passage 71 and the pump downstream side flow passage 72 by the first communication passage 41 and the second communication passage 42. Also, the pressure before and after the pump 12 refers to the pressure upstream and downstream of the pump 12.

[0052] By using the front and rear pressures of the pump 12 to operate the diaphragm 24 and drive the drive shaft 25, the first outlet flow path 22-1 and the second outlet flow path 22-2 can be opened and closed by the valve body 26, thereby switching the flow paths.

[0053] At this time, the pressure before and after the pump 12 can be transmitted to the back pressure chamber 31 without the flow of cooling water through the first communication passage 41 or the second communication passage 42. This makes it possible to suppress a decrease in the pump efficiency of the pump 12. Therefore, it is possible to switch the flow path by utilizing the pressure before and after the pump 12 while suppressing a decrease in the pump efficiency.

[0054] In addition, since the operating force of the flow path switching valve unit 11 depends on the diameter of the diaphragm chamber 23, the operating force of the flow path switching valve unit 11 can be increased by increasing the diameter of the diaphragm chamber 23 without increasing the number of turns of the coil as in the case of a solenoid valve, for example. Therefore, the size and manufacturing costs of the flow path switching device 1 can be reduced.

[0055] In addition, since the diaphragm 24 only moves up and down, there is no need to worry about foreign matter getting caught in it.

[0056] Furthermore, since it is possible to reduce the passage diameter of the pressure transmission passage 60 formed between the pilot valve 51 and the diaphragm chamber 23, it becomes possible to adjust the pressure fluctuation speed.

[0057] Furthermore, since the diaphragm 24 is used to move the valve element 26, there is no risk of a decrease in thrust due to a large stroke, as occurs when a piston is used to move the valve element 26.

[0058] Moreover, by increasing the stroke amount of the valve body 26, the pressure loss can be reduced.

[0059] In addition, the pilot valve 51 is switched to either a state in which the back pressure chamber 31 communicates with the pump upstream flow path 71 via the first communication passage 41, or a state in which the back pressure chamber 31 communicates with the pump downstream flow path 72 via the second communication passage 42.

[0060] In this manner, the flow paths can be switched with a simple configuration by utilizing the pressure before and after the pump 12. Therefore, the manufacturing cost of the flow path switching device 1 can be suppressed.

[0061] In addition, in the flow path switching device 1, the diaphragm 24 is used as a movable wall that drives the drive shaft 25.

[0062] In this manner, the diaphragm 24, which is relatively inexpensive, is used, so that the manufacturing cost of the flow path switching device 1 can be reduced.

[0063] The flow path switching device 1 is a device in which the flow path switching valve unit 11 and the pump 12 are integrally formed.

[0064] As a result, the pump 12 can be configured as a drive section for the flow path switching valve section 11, and the flow path switching device 1 can be made compact and low-cost.

[0065] The flow path switching device 1 is mounted on a flow path of cooling water of an electric vehicle.

[0066] This allows the flow of cooling water for the electric vehicle to be efficiently controlled by the flow path switching device 1. This improves the energy efficiency of the electric vehicle and contributes to carbon neutrality.

[0067] <Second embodiment> Next, a flow path switching device 2 of the second embodiment will be described. Differences from the flow path switching device 1 of the first embodiment will be described, and descriptions of points in common with the flow path switching device 1 of the first embodiment will be omitted.

[0068] [First Example] First, a first embodiment of the flow path switching device 2 will be described.

[0069] (Configuration of flow path switching device) 8, in the flow path switching device 2 of this embodiment, the diaphragm chamber 23 is sealed by a lip seal 28 and is cut off from the first outlet flow path 22-1. The diaphragm chamber 23 includes a back pressure chamber 31 and an intermediate chamber 32 separated from the back pressure chamber 31 by the diaphragm 24.

[0070] Moreover, the flow path switching device 2 of this embodiment has a first communication passage 81, a second communication passage 82, and a pilot valve 91.

[0071] The first communication passage 81 is a passage that communicates the back pressure chamber 31 with the pump upstream flow passage 71. The second communication passage 82 is a passage that communicates the intermediate chamber 32 with the pump downstream flow passage 72. The second communication passage 82 is formed of a first portion 101 and a second portion 102. The first portion 101 is a portion formed between the intermediate chamber 32 and the pilot valve 91. The second portion 102 is a portion formed between the pilot valve 91 and the pump downstream flow passage 72.

[0072] Furthermore, in the flow path switching device 2 of this embodiment, an intermediate passage 83 is provided as a passage that connects the first communication passage 81 and the first portion 101 of the second communication passage 82 with each other.

[0073] The pilot valve 91 is a valve that switches the communication state between the first communication passage 81 and the second communication passage 82. That is, the pilot valve 91 can be switched between a state in which the first portion 101 and the second portion 102 of the second communication passage 82 are blocked while the first portion 101 and the intermediate passage 83 are connected, or a state in which the first portion 101 and the second portion 102 are connected while the first portion 101 and the intermediate passage 83 are blocked. The pilot valve 91 is an example of a "communication state switching valve" in the present disclosure.

[0074] (Function of flow path switching device) In this embodiment, the pilot valve 91 is switched between a state in which the first communication passage 81 communicates with the first portion 101 of the second communication passage 82 via the intermediate passage 83, thereby communicating both the back pressure chamber 31 and the intermediate chamber 32 with the pump upstream flow path 71 (see Figure 8, etc.), or a state in which the back pressure chamber 31 communicates with the pump upstream flow path 71 via the first communication passage 81 and the intermediate chamber 32 communicates with the pump downstream flow path 72 via the second communication passage 82 (see Figure 10, etc.).

[0075] 8, the back pressure chamber 31 communicates with the pump upstream side flow path 71 via the first communication passage 81. When there is no flow of cooling water in the first communication passage 81, the pressure of the pump upstream side flow path 71 is transmitted to the back pressure chamber 31.

[0076] In addition, the pilot valve 91 is in the OFF state, and the first portion 101 and the second portion 102 of the second communication passage 82 are blocked from communication with each other, while the first portion 101 and the intermediate passage 83 are in communication with each other.

[0077] As a result, the intermediate chamber 32 is in communication with the pump upstream flow path 71 via the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81. Then, in a state in which no cooling water flows through the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81, the pressure of the pump upstream flow path 71 is transmitted to the intermediate chamber 32. In addition, the force of the spring 33 acts downward on the diaphragm 24.

[0078] Furthermore, since the valve element 26 is in contact with the second valve seat 27-2 and the valve hole of the first valve seat 27-1 is open, a flow path is formed by the inlet flow path 21 and the first outlet flow path 22-1, and the cooling water flows from the inlet flow path 21 to the first outlet flow path 22-1. The pressure of the cooling water flowing from the inlet flow path 21 to the first outlet flow path 22-1 acts downward on the valve element 26. In this way, the flow path switching device 2 is in an upstream flow holding state.

[0079] Next, as shown in FIG. 9, when the pilot valve 91 is switched to the ON state, the first portion 101 of the second communication passage 82 and the intermediate passage 83 are blocked, while the first portion 101 of the second communication passage 82 and the second portion 102 are connected to each other.

[0080] As a result, the intermediate chamber 32 communicates with the pump downstream flow path 72 through the second communication passage 82. The pressure Pb in the intermediate chamber 32 is lower than the pressure P3 in the pump downstream flow path 72. Therefore, the cooling water in the pump downstream flow path 72 flows into the intermediate chamber 32, so that the pressure Pb in the intermediate chamber 32 increases, and an upward force acts on the diaphragm 24.

[0081] The back pressure chamber 31 is also connected to the pump upstream flow path 71 via a first communication passage 81. The pressure Pa of the back pressure chamber 31 is higher than the pressure P0 of the pump upstream flow path 71. Therefore, the cooling water in the back pressure chamber 31 is discharged to the pump upstream flow path 71, so that the pressure Pa of the back pressure chamber 31 decreases and an upward force acts on the diaphragm 24.

[0082] Then, the diaphragm 24 moves upward to drive the drive shaft 25 upward, so that the valve element 26 moves away from the second valve seat 27-2. In this way, the flow path switching device 2 is switched to the downstream flow.

[0083] 10, when the pilot valve 91 is subsequently maintained in the ON state, the valve element 26 abuts against the first valve seat 27-1. This opens the valve hole of the second valve seat 27-2, so that a flow path is formed by the inlet flow path 21 and the second outlet flow path 22-2, and the cooling water flows from the inlet flow path 21 to the second outlet flow path 22-2. Then, the pressure of the cooling water flowing from the inlet flow path 21 to the second outlet flow path 22-2 acts upward on the valve element 26. In this way, the flow path switching device 2 is in the downstream flow holding state.

[0084] Next, as shown in FIG. 11, when the pilot valve 91 is switched to the OFF state, the first portion 101 of the second communication passage 82 is connected to the intermediate passage 83, while the first portion 101 of the second communication passage 82 is blocked from the second portion 102.

[0085] As a result, the intermediate chamber 32 is communicated with the pump upstream flow path 71 via the first portion 101 of the second communication path 82, the intermediate passage 83, and the first communication path 81. The pressure Pb of the intermediate chamber 32 is higher than the pressure P0 of the pump upstream flow path 71. Therefore, the cooling water in the intermediate chamber 32 is discharged to the pump downstream flow path 72, and the pressure Pb of the intermediate chamber 32 decreases.

[0086] The back pressure chamber 31 is also connected to the pump upstream flow path 71 via a first communication passage 81. The pressure Pa of the back pressure chamber 31 is lower than the pressure P0 of the pump upstream flow path 71. Therefore, the cooling water in the pump upstream flow path 71 flows into the back pressure chamber 31, and the pressure Pa of the back pressure chamber 31 increases.

[0087] Then, the diaphragm 24 moves downward to drive the drive shaft 25 downward, so that the valve element 26 moves away from the first valve seat 27-1. In this way, the flow path switching device 2 is switched to the upstream flow state.

[0088] Thereafter, when the pilot valve 91 is maintained in the OFF state, the flow path switching device 2 again goes into the upstream flow holding state as shown in FIG.

[0089] (Effects of this embodiment) According to this embodiment, the pilot valve 91 is switched between a state in which the first communication passage 81 and the second communication passage 82 are connected via the intermediate passage 83, thereby connecting both the back pressure chamber 31 and the intermediate chamber 32 to the pump upstream flow path 71, or a state in which the back pressure chamber 31 is connected to the pump upstream flow path 71 via the first communication passage 81 and the intermediate chamber 32 is connected to the pump downstream flow path 72 via the second communication passage 82.

[0090] In this way, it is possible to adjust the pressure in the intermediate chamber 32 in addition to the back pressure chamber 31, and it is possible to improve the responsiveness of the operation of the valve body 26. Therefore, it is possible to improve the responsiveness of the switching of the flow path.

[0091] [Second Example] Next, a second embodiment of the flow path switching device 2 will be described. Differences from the first embodiment will be described, and descriptions of commonalities with the first embodiment will be omitted.

[0092] (Configuration of flow path switching device) In this embodiment, as shown in FIG. 12, a throttle 111 is provided in the second portion 102 of the second communication passage 82.

[0093] (Function of flow path switching device) In this embodiment, the pilot valve 91 is switched between a state in which the first portion 101 of the second communication passage 82 is connected to the first communication passage 81 via the intermediate passage 83, thereby connecting both the backpressure chamber 31 and the intermediate chamber 32 to both the pump upstream flow path 71 and the pump downstream flow path 72, respectively (see Figure 12, etc.), or a state in which the backpressure chamber 31 is connected to the pump upstream flow path 71 via the first communication passage 81 and the intermediate chamber 32 is connected to the pump downstream flow path 72 via the second communication passage 82 (see Figure 13, etc.).

[0094] 12, the back pressure chamber 31 communicates with the pump upstream side flow path 71 via the first communication passage 81. In addition, the pilot valve 91 is in the OFF state, and the back pressure chamber 31 communicates with the pump downstream side flow path 72 via the first communication passage 81, the intermediate passage 83, and the second portion 102 of the second communication passage 82.

[0095] The intermediate chamber 32 communicates with the pump downstream flow path 72 via the second communication passage 82. In addition, the pilot valve 91 is in the OFF state, and the intermediate chamber 32 communicates with the pump upstream flow path 71 via the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81.

[0096] In this way, the pilot valve 91 connects the first communication passage 81 and the second communication passage 82 via the intermediate passage 83, thereby connecting both the back pressure chamber 31 and the intermediate chamber 32 to both the pump upstream flow path 71 and the pump downstream flow path 72.

[0097] The pump downstream flow passage 72 is connected to the pump upstream flow passage 71 via the second portion 102 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81. The pressure P3 of the pump downstream flow passage 72 is higher than the pressure P0 of the pump upstream flow passage 71. Therefore, a slight leakage of the cooling water occurs from the pump downstream flow passage 72 to the pump upstream flow passage 71 via the throttle 111.

[0098] Since the valve element 26 is in contact with the second valve seat 27-2 and the valve hole of the first valve seat 27-1 is open, a flow path is formed by the inlet flow path 21 and the first outlet flow path 22-1, and the cooling water flows from the inlet flow path 21 to the first outlet flow path 22-1. The pressure of the cooling water flowing from the inlet flow path 21 to the first outlet flow path 22-1 acts downward on the valve element 26. In this way, the flow path switching device 2 is in an upstream flow holding state.

[0099] Next, as shown in FIG. 13, when the pilot valve 91 is switched to the ON state, the second communication passage 82 and the intermediate passage 83 are blocked from each other.

[0100] As a result, the intermediate chamber 32 communicates with the pump downstream flow path 72 via the second communication passage 82. The pressure Pb in the intermediate chamber 32 is lower than the pressure P3 in the pump downstream flow path 72. Therefore, in a state where there is no flow of cooling water in the second communication passage 82, the pressure in the pump downstream flow path 72 is transmitted to the intermediate chamber 32 via the second communication passage 82, and the pressure Pb in the intermediate chamber 32 increases. In this way, the flow path switching device 2 is in an initial state before starting to switch to the downstream flow.

[0101] 14, when the pilot valve 91 is maintained in the ON state, the pressure Pa in the back pressure chamber 31 is higher than the pressure P0 in the pump upstream flow path 71, so that the cooling water is discharged from the back pressure chamber 31 to the pump upstream flow path 71 via the first communication passage 81. Also, the pressure Pb in the intermediate chamber 32 is lower than the pressure P3 in the pump downstream flow path 72, so that the cooling water flows from the pump downstream flow path 72 to the intermediate chamber 32 via the second communication passage 82.

[0102] As a result, the pressure Pa in the back pressure chamber 31 decreases, while the pressure Pb in the intermediate chamber 32 increases. Then, when the condition of the following formula is satisfied, the diaphragm 24 moves upward, the drive shaft 25 starts to move upward, and the valve body 26 starts to move away from the second valve seat 27-2. In this way, the flow path switching device 2 is switched to a downstream flow switching valve open state. [Number 1] ((diameter of valve body 26) × P3 + force of spring 33) < (diameter of diaphragm 24 × Pb)

[0103] Next, as shown in FIG. 15, when the pilot valve 91 maintains the ON state, the valve element 26 moves away from the second valve seat 27-2, and the flow path switching device 2 enters a state in which the valve is midway switched to the downstream flow.

[0104] Thereafter, when the condition of the following formula is satisfied, the valve body 26 comes into contact with the first valve seat 27-1. [Number 2] ((diameter of diaphragm 24) x Pb) > (force of spring 33)

[0105] 16, when the pilot valve 91 maintains the ON state and the condition of the following formula is satisfied, the valve body 26 maintains the state of abutting against the first valve seat 27-1. As a result, the valve hole of the second valve seat 27-2 is opened, so that a flow path is formed by the inlet flow path 21 and the second outlet flow path 22-2, and the cooling water flows from the inlet flow path 21 to the second outlet flow path 22-2. In this way, the flow path switching device 1 is in the downstream flow holding state. [Number 3] ((diameter of valve body 26) × P3 + (diameter of diaphragm 24) × Pb) < (force of spring 33)

[0106] Next, as shown in FIG. 17, when the pilot valve 91 is switched to the OFF state, the second communication passage 82 and the intermediate passage 83 are communicated with each other.

[0107] As a result, the intermediate chamber 32 communicates with the pump upstream side flow path 71 through the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81. The pressure Pb of the intermediate chamber 32 is higher than the pressure P0 of the pump upstream side flow path 71. Therefore, in a state where there is no flow of cooling water through the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81, the pressure Pb of the intermediate chamber 32 is transmitted to the pump upstream side flow path 71 through the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81, and the pressure Pb of the intermediate chamber 32 decreases. In this way, the flow path switching device 2 is in an initial state of starting to switch to the upstream flow. The intermediate chamber 32 communicates with the pump downstream side flow path 72 through the second communication passage 82.

[0108] The back pressure chamber 31 is also connected to the pump downstream flow path 72 via the first communication passage 81, the intermediate passage 83, and the second portion 102 of the second communication passage 82. The back pressure chamber 31 is also connected to the pump upstream flow path 71 via the first communication passage 81.

[0109] In this way, the pilot valve 91 connects the first communication passage 81 and the second communication passage 82 via the intermediate passage 83, thereby connecting both the back pressure chamber 31 and the intermediate chamber 32 to both the pump upstream flow path 71 and the pump downstream flow path 72.

[0110] 18, when the pilot valve 91 is maintained in the OFF state, the pressure Pa in the backpressure chamber 31 is lower than the pressure P0 in the pump upstream flow path 71, so that cooling water flows from the pump upstream flow path 71 to the backpressure chamber 31 via the first communication passage 81. Also, the pressure Pb in the intermediate chamber 32 is higher than the pressure P0 in the pump upstream flow path 71, so that cooling water is discharged from the intermediate chamber 32 via the first portion 101 of the second communication passage 82, the intermediate passage 83, and the first communication passage 81 to the pump upstream flow path 71.

[0111] As a result, the pressure Pa in the back pressure chamber 31 increases, while the pressure Pb in the intermediate chamber 32 decreases. Then, when the condition of the following formula is satisfied, the diaphragm 24 moves downward, the drive shaft 25 starts to move downward, and the valve body 26 starts to move away from the first valve seat 27-1. In this way, the flow path switching device 2 is switched to the upstream flow switching valve open state. [Number 4] ((Diameter of valve body 26) × P3) < (Force of spring 33)

[0112] Next, as shown in FIG. 19, when the pilot valve 91 maintains the OFF state, the valve element 26 moves away from the first valve seat 27-1, and the flow path switching device 2 enters a state in which the valve is in the middle of switching to the upstream flow.

[0113] Thereafter, the valve element 26 abuts against the second valve seat 27-2 due to the force of the spring 33. Then, if the pilot valve 91 maintains the OFF state thereafter, the flow path switching device 2 enters the upstream flow holding state (see FIG. 12).

[0114] (Effects of this embodiment) According to this embodiment, the pilot valve 91 is switched between a state in which the first communication passage 81 and the second communication passage 82 are connected via the intermediate passage 83, thereby connecting both the back pressure chamber 31 and the intermediate chamber 32 to both the pump upstream flow passage 71 and the pump downstream flow passage 72, respectively, or a state in which the back pressure chamber 31 is connected to the pump upstream flow passage 71 via the first communication passage 81 and the intermediate chamber 32 is connected to the pump downstream flow passage 72 via the second communication passage 82.

[0115] This makes it possible to adjust the pressure in the intermediate chamber 32 in addition to the back pressure chamber 31, thereby improving the responsiveness of the operation of the valve body 26. As a result, the responsiveness of the switching of the flow path can be improved.

[0116] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure.

[0117] For example, the above description has exemplified the flow path switching system of the present disclosure as a flow path switching device 1, which is a single device in which the flow path switching valve section 11 and the pump 12 are integrally formed, but other examples include systems in which the flow path switching valve section 11 and the pump 12 are formed separately. [Explanation of symbols]

[0118] 1 Flow path switching device 2. Flow path switching device 11 Flow path switching valve section 12 Pump 21 Inlet channel 22-1 First outlet flow path 22-2 Second outlet flow path 23 Diaphragm chamber 24 Diaphragm 25 Drive shaft 26 Valve body 31 Back pressure chamber 32 Intermediate Room 41 1st communication passage 42 2nd communication passage 51 Pilot valve 71 Pump upstream flow passage 72 Pump downstream flow path 81 1st communication passage 82 2nd communication passage 83 Middle Passage 91 Pilot valve

Claims

1. A flow path switching valve unit; a pump for supplying a fluid to the flow path switching valve unit, the flow path switching valve unit includes an inlet flow path for introducing the fluid pumped by the pump, a first outlet flow path and a second outlet flow path branching from the inlet flow path for outletting the fluid, a movable wall chamber, a movable wall disposed within the movable wall chamber, a drive shaft connected to the movable wall, and a valve body provided on the drive shaft, and the flow path switching system switches the flow paths by operating the movable wall to drive the drive shaft, thereby opening and closing the first outlet flow path and the second outlet flow path by the valve body, a first communication passage that communicates the movable wall chamber with an upstream flow passage of the pump; a second communication passage that communicates the movable wall chamber with a downstream flow passage of the pump; a communication state switching valve that switches a communication state between the first communication passage and the second communication passage; A flow path switching system characterized by:

2. 2. The flow path switching system of claim 1, The movable wall chamber includes a back pressure chamber partitioned by the movable wall, The communication state switching valve is a state in which the back pressure chamber is communicated with an upstream flow path of the pump through the first communication passage; or A state in which the back pressure chamber and the downstream side flow passage of the pump are communicated with each other through the second communication passage. Switch between A flow path switching system characterized by:

3. 2. The flow path switching system of claim 1, The movable wall chamber includes a back pressure chamber and an intermediate chamber separated from the back pressure chamber by the movable wall, the first communication passage is a passage that communicates the back pressure chamber with an upstream flow path of the pump, the second communication passage is a passage that communicates the intermediate chamber with a downstream flow path of the pump, an intermediate passage is provided as a passage that communicates the first communication passage and the second communication passage, The communication state switching valve is a state in which the first communication passage and the second communication passage are communicated with each other via the intermediate passage, so that both the back pressure chamber and the intermediate chamber are communicated with an upstream flow path of the pump; or a state in which the back pressure chamber is communicated with an upstream flow passage of the pump through the first communication passage, and the intermediate chamber is communicated with a downstream flow passage of the pump through the second communication passage; Switch between A flow path switching system characterized by:

4. 2. The flow path switching system of claim 1, The movable wall chamber includes a back pressure chamber and an intermediate chamber separated from the back pressure chamber by the movable wall, the first communication passage is a passage that communicates the back pressure chamber with an upstream flow path of the pump, the second communication passage is a passage that communicates the intermediate chamber with a downstream flow path of the pump, an intermediate passage is provided as a passage that communicates the first communication passage and the second communication passage, The communication state switching valve is a state in which the first communication passage and the second communication passage are communicated with each other via the intermediate passage, so that both the back pressure chamber and the intermediate chamber are communicated with both the upstream flow path of the pump and the downstream flow path of the pump, respectively; or a state in which the back pressure chamber is communicated with an upstream flow passage of the pump through the first communication passage, and the intermediate chamber is communicated with a downstream flow passage of the pump through the second communication passage; Switch between A flow path switching system characterized by:

5. 5. The flow path switching system according to claim 1 , the movable wall being a diaphragm; A flow path switching system characterized by:

6. 5. The flow path switching system according to claim 1 , the flow path switching system is a flow path switching device in which the flow path switching valve unit and the pump are integrally formed; A flow path switching system characterized by:

7. 5. The flow path switching system according to claim 1 , The flow path switching system is installed in a flow path of cooling water of an electric vehicle; A flow path switching system characterized by:

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