Electrically driven valve

Abstract

Provided is an electrically driven valve capable of effectively suppressing noise generated when a main valve port is opened. An electrically driven valve (1) has: a valve main body (10); a main valve spool (20) configured to divide a main valve chamber (13) and a back pressure chamber (14); a pressure equalizing passage (26) connecting the main valve chamber (13) and the back pressure chamber (14); a pilot passage (25) connecting the back pressure chamber (14) and a main valve port (15); and a pilot valve spool (40) that opens and closes the pilot passage (25). The solenoid valve (1) has a flow path switching mechanism (60) that switches the pilot passage (25) to a first passage mode in which the flow path area is smaller than the pressure equalizing passage (26) and a second passage mode in which the flow path area is larger than the pressure equalizing passage (26). Furthermore, the flow path switching mechanism (60) is configured to switch to the first passage mode when the pressure difference between the fluid pressure of the back pressure chamber (14) and the fluid pressure of the main valve port (15) is large and to switch to the second passage mode when the pressure difference is small.

Description

Technical Field

[0001] This invention relates to an electrically driven valve. Background Technology

[0002] Patent Document 1 discloses a pilot-operated solenoid valve as an example of a conventional electrically driven valve. The solenoid valve of Patent Document 1 has a valve body and a main valve core. The valve body has a main valve chamber and a back pressure chamber. The main valve chamber and the back pressure chamber are divided by the main valve core. The main valve chamber is connected to the main valve port via a main valve seat. An inlet connector pipe connected to the main valve chamber and an outlet connector pipe connected to the main valve port are engaged with the valve body. When the main valve core contacts the main valve seat, the main valve port is closed; when the main valve core separates from the main valve seat, the main valve port is opened. The main valve core has a pilot passage. The pilot passage connects the back pressure chamber and the main valve port. An opening spring is disposed in the main valve chamber. The opening spring presses the main valve core from the main valve chamber side towards the back pressure chamber side.

[0003] Additionally, the solenoid valve includes a pilot valve core, a plunger, a fixed iron core, and a coil. The pilot valve core is located in the back pressure chamber. The pilot valve core opens and closes the pilot passage. The pilot valve core is mounted on the plunger. A plunger spring is disposed between the plunger and the fixed iron core. The plunger spring presses the plunger towards the main valve core.

[0004] When the coil is not energized, the plunger moves towards the main valve spool via the plunger spring. The plunger presses the pilot valve spool against the main valve spool, thereby closing the pilot passage. Furthermore, the pilot valve spool presses the main valve spool against the main valve seat, thereby closing the main valve port. Thus, the flow of fluid from the main valve chamber to the main valve port is cut off (valve closed). In the valve closed state, the fluid pressure in the main valve chamber is the same as the fluid pressure in the back pressure chamber, while the fluid pressure at the main valve port is lower than both the fluid pressure in the main valve chamber and the back pressure chamber.

[0005] Furthermore, when the coil is energized, the plunger moves towards the fixed iron core side by magnetic force. The plunger causes the pilot valve spool to separate from the main valve spool, thereby opening the pilot passage. Through the pilot passage, fluid in the back pressure chamber flows towards the main valve port, thereby reducing the fluid pressure in the back pressure chamber. Due to the pressure difference between the opening spring and the fluid pressure in the main valve chamber and the back pressure chamber, the main valve spool separates from the main valve seat, thereby opening the main valve port. Therefore, fluid in the main valve chamber flows towards the main valve port.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2007-92825

[0009] The technical problem that the invention aims to solve

[0010] In the aforementioned solenoid valve, when the main valve port is opened, the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure at the main valve port is large, causing the fluid in the main valve chamber to flow rapidly into the main valve port, thus generating noise (fluid sound). Summary of the Invention

[0011] Therefore, the object of the present invention is to provide an electrically driven valve that can effectively suppress the noise generated when the main valve port is opened.

[0012] Technical means for solving technical problems

[0013] To achieve the above objectives, an electrically driven valve according to one aspect of the present invention comprises: a valve body having a main valve chamber and a back pressure chamber; a main valve core configured to divide the main valve chamber and the back pressure chamber and to open and close a main valve port connected to the main valve chamber; a pressure equalization passage connecting the main valve chamber and the back pressure chamber; a pilot passage connecting the back pressure chamber and the main valve port; a pilot valve core opening and closing the pilot passage; and a drive unit driving the pilot valve core. The electrically driven valve has a flow path switching mechanism that switches the pilot passage to a first flow path with a flow area smaller than that of the pressure equalization passage and a second flow path with a flow area larger than that of the pressure equalization passage. The flow path switching mechanism is configured such that, when the pilot passage is open, it switches to the first flow path when the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure in the main valve port is large, and switches to the second flow path when the pressure difference is small.

[0014] According to the present invention, an electrically driven valve has a flow path switching mechanism that switches the pilot passage to a first passage mode with a flow path area smaller than that of the pressure equalization passage and a second passage mode with a flow path area larger than that of the pressure equalization passage. Furthermore, the flow path switching mechanism is configured such that, when the pilot passage is open, the pilot passage is switched to the first passage mode when the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port is large, and the pilot passage is switched to the second passage mode when the pressure difference is small. In the electrically driven valve, in the closed state with the main valve port closed, the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber are the same value (including almost the same value), and the fluid pressure at the main valve port is lower than these fluid pressures. Therefore, when the pilot passage is just opened, the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port is large, and the flow path switching mechanism switches the pilot passage to the first passage mode with a smaller flow path area, thereby making the flow rate between the back pressure chamber and the main valve port smaller than the flow rate between the main valve chamber and the back pressure chamber. Therefore, the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber are maintained at almost the same value and gradually decrease. Furthermore, when the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port decreases, the flow path switching mechanism switches the pilot path to a second path with a larger flow area, thus making the flow rate between the back pressure chamber and the main valve port greater than the flow rate between the main valve chamber and the back pressure chamber. Consequently, the fluid pressure in the back pressure chamber becomes lower than the fluid pressure in the main valve chamber. Due to the pressure difference between the fluid pressures in the main valve chamber and the back pressure chamber, the main valve core separates from the main valve seat, thereby opening the main valve port. At this time, the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure at the main valve port becomes smaller than when the pilot path just opened. Therefore, it is possible to suppress the rapid inflow of fluid from the main valve chamber into the main valve port, thereby effectively suppressing the noise generated when the main valve port opens.

[0015] To achieve the above objectives, another aspect of the electrically driven valve of the present invention comprises: a valve body having a main valve chamber and a back pressure chamber; a main valve core configured to divide the main valve chamber and the back pressure chamber and to open and close a main valve port connected to the main valve chamber; a pressure equalization passage connecting the main valve chamber and the back pressure chamber; a pilot passage connecting the back pressure chamber and the main valve port; a pilot valve core opening and closing the pilot passage; and a drive unit driving the pilot valve core. The electrically driven valve has a flow path switching mechanism that switches the pressure equalization passage to a first path mode with a flow area smaller than that of the pilot passage. The second path mode has a flow path area larger than the pilot path. The flow path switching mechanism is configured such that, when the pilot path is open, (1) when the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber is large and the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure in the main valve port is large, the flow path is switched to the second path mode; (2-1) when the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber is small, or (2-2) when the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber is large and the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure in the main valve port is small, the flow path is switched to the first path mode.

[0016] According to the present invention, the electrically driven valve has a flow path switching mechanism that switches the pressure equalization passage to a first passage mode with a flow path area smaller than that of the pilot passage and a second passage mode with a flow path area larger than that of the pilot passage. Furthermore, the flow path switching mechanism is configured such that, in the pilot passage open state, (1) when the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber is large, and the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port is large, the flow path is switched to the second passage mode; (2-1) when the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber is small, or (2-2) when the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber is large, and the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port is small, the pressure equalization passage is switched to the first passage mode. In the electrically driven valve, in the closed state with the main valve port closed, the fluid pressure in the main valve chamber and the fluid pressure in the back pressure chamber are the same value (including almost the same value), and the fluid pressure at the main valve port is lower than these fluid pressures. Therefore, when the pilot passage is first opened, the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port is large. Fluid flows from the back pressure chamber to the main valve port, increasing the pressure difference between the fluid pressure in the main valve chamber and the back pressure chamber. At this time, the flow path switching mechanism switches the pressure equalization passage to a second passage with a larger flow area, resulting in a greater flow rate between the main valve chamber and the back pressure chamber than between the back pressure chamber and the main valve port. Consequently, the fluid pressure in the main valve chamber and the back pressure chamber gradually decreases and approaches each other, reducing the pressure difference between them. Furthermore, when the pressure difference between the main valve chamber and the back pressure chamber decreases, the flow path switching mechanism switches the pressure equalization passage to a first passage with a smaller flow area, resulting in a smaller flow rate between the main valve chamber and the back pressure chamber than between the back pressure chamber and the main valve port. Therefore, compared to the fluid pressure in the main valve chamber, the fluid pressure in the back pressure chamber decreases, resulting in a larger pressure difference between the fluid pressure in the main valve chamber and the back pressure chamber, and a smaller pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port. Furthermore, the pressure difference between the fluid pressure in the main valve chamber and the back pressure chamber causes the main valve core to separate from the main valve seat, thereby opening the main valve port. At this time, the pressure difference between the fluid pressure in the main valve chamber and the fluid pressure at the main valve port becomes smaller than when the pilot passage was first opened. Therefore, it is possible to suppress the rapid inflow of fluid from the main valve chamber into the main valve port, thereby effectively suppressing the noise generated when the main valve port opens.

[0017] In this invention, preferably, the flow path switching mechanism comprises: a flow path switching valve core having a first flow hole; a valve seat having a second flow hole with a diameter larger than the first flow hole; and a pressure differential working spring configured to press the flow path switching valve core upstream. The flow path switching valve core contacts and separates from the valve seat based on the pressure difference between the fluid pressure on the upstream side and the fluid pressure on the downstream side. The mechanism is configured such that when the flow path switching valve core contacts the valve seat, fluid flows through the first flow hole; and when the flow path switching valve core separates from the valve seat, fluid flows through the second flow hole. Thus, the pressure difference between the fluid pressure on the upstream side and the fluid pressure on the downstream side can be used to allow fluid to flow through either the small-diameter first flow hole or the large-diameter second flow hole, thereby switching between a first flow path and a second flow path. Therefore, the flow path switching mechanism can have a simpler structure.

[0018] The effects of the invention

[0019] According to the present invention, noise generated when the main valve port is opened can be effectively suppressed. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the solenoid valve according to the first embodiment of the present invention.

[0021] Figure 2 yes Figure 1 An enlarged cross-sectional view of the solenoid valve (closed state).

[0022] Figure 3 yes Figure 1 Enlarged cross-sectional view of the solenoid valve (intermediate state 1).

[0023] Figure 4 yes Figure 1 Enlarged cross-sectional view of the solenoid valve (intermediate state 2).

[0024] Figure 5 yes Figure 1 An enlarged cross-sectional view of the solenoid valve (open state).

[0025] Figure 6 This is a cross-sectional view of the solenoid valve according to the second embodiment of the present invention.

[0026] Figure 7 yes Figure 6 An enlarged cross-sectional view of the solenoid valve (closed state).

[0027] Figure 8 yes Figure 6 Enlarged cross-sectional view of the solenoid valve (intermediate state 1).

[0028] Figure 9 yes Figure 6 Enlarged cross-sectional view of the solenoid valve (intermediate state 2).

[0029] Figure 10 yes Figure 6 An enlarged cross-sectional view of the solenoid valve (open state).

[0030] Figure 11 This is a cross-sectional view of the solenoid valve according to the third embodiment of the present invention.

[0031] Figure 12 It is along Figure 11 A sectional view of line XII-XII.

[0032] Figure 13 It means Figure 11 A cross-sectional view of a portion of the solenoid valve (with the second main valve port closed).

[0033] Figure 14 It means Figure 11 A cross-sectional view of a portion of the solenoid valve (mid-way state 1).

[0034] Figure 15 It means Figure 11 A cross-sectional view of a portion of the solenoid valve (mid-way state 2).

[0035] Figure 16 It means Figure 11 A cross-sectional view of a portion of the solenoid valve (with the second main valve port open).

[0036] Figure 17 This is a cross-sectional view of the solenoid valve according to the fourth embodiment of the present invention.

[0037] Figure 18 It means Figure 17 A cross-sectional view of a portion of the solenoid valve (with the second main valve port closed).

[0038] Figure 19 It means Figure 17 A cross-sectional view of a portion of the solenoid valve (mid-way state 1).

[0039] Figure 20 It means Figure 17 A cross-sectional view of a portion of the solenoid valve (mid-way state 2).

[0040] Figure 21 It means Figure 17 A cross-sectional view of a portion of the solenoid valve (with the second main valve port open).

[0041] Symbol Explanation

[0042] (First Embodiment)

[0043] 1…Solenoid valve, 10…Valve body, 11…Peripheral wall, 12…Bottom wall, 13…Main valve chamber, 14…Back pressure chamber, 15…Main valve port, 16…Main valve seat, 17…Inlet connector pipe, 18…Outlet connector pipe, 20…Main valve core, 21…Main valve core body, 21a…Main valve section, 21b…Pilot valve seat, 22…Flange, 25…Pilot passage, 25a…Large diameter section, 25b…Small diameter section, 26, 26E…Equalizing passage, 30 …Drive unit, 31…Housing, 32…Coil, 33…Fixed iron core, 34…Plug, 35…Plug spring, 40…Pilot valve core, 60…Flow path switching mechanism, 61…Flow path switching valve core, 61a…Switching valve unit, 61b…Guide unit, 61c…First flow hole, 61d…Through hole, 62…Valve seat unit, 62c…Second flow hole, 63…Pressure differential working spring, F1…First passage mode, F2…Second passage mode;

[0044] (Second Embodiment)

[0045] 2…Solenoid valve, 26, 26E…Equalizing pressure passage, 70…Flow path switching mechanism, 71…Flow path switching valve core, 71a…Switching valve part, 71b…Guide part, 71c…First flow hole, 71d…Through hole, 72…Valve seat part, 72c…Second flow hole, 73…Pressure differential working spring, 74…Spring support component, G1…First passage mode, G2…Second passage mode;

[0046] (Third Embodiment)

[0047] 3…Solenoid valve, 110…Valve body, 110a…First space, 110b…Second space, 110c…Inlet flow path, 110d…Intermediate flow path, 110e…Outlet flow path, 110f…Third space, 110g…Actuator rod insertion hole, 113…First main valve chamber, 114…First back pressure chamber, 115…First main valve port, 116…First main valve seat, 120…First main valve core, 121…First main valve core body, 121a…First main valve section, 121b…First pilot valve seat, 122…First flange, 125…First pilot passage, 126…First equalizing passage, 128…Actuator rod, 128a…Fluid passage, 130…Driver section 140…First pilot valve core, 213…Second main valve chamber, 214…Second back pressure chamber, 215…Second main valve port, 216…Second main valve seat, 220…Second main valve core, 221…Second main valve core body, 221a…Second main valve section, 222…Second flange, 225…Second pilot passage, 225a…front half of passage, 225b…rear half of passage, 226, 226E…Second equalizing passage, 228…Second pilot valve chamber, 228a…top surface, 228b…Second pilot valve seat, 228c…contact area, 229…spring chamber, 240…Second pilot valve core, 241…frame, 242…gasket, 260…flow path switching mechanism;

[0048] (Fourth Embodiment)

[0049] 4…Solenoid valve, 270…Flow path switching mechanism. Detailed Implementation

[0050] (First Embodiment)

[0051] The following is for reference Figures 1-5 The first embodiment of the electrically driven valve of the present invention, a pilot-operated solenoid valve, will be described.

[0052] Figure 1 This is a cross-sectional view of the solenoid valve according to the first embodiment of the present invention. Figures 2-5 yes Figure 1 An enlarged sectional view of the valve body and its surrounding area of ​​the solenoid valve. Figures 2-5 The states are represented in sequence as follows: closed valve state, intermediate state 1 (pilot path is in the first path mode), intermediate state 2 (pilot path is in the second path mode), and open valve state.

[0053] like Figures 1-5 As shown, the solenoid valve 1 of the first embodiment includes a valve body 10, a main valve core 20, a drive unit 30, a pilot valve core 40, and a flow path switching mechanism 60.

[0054] The valve body 10 has a bottomed cylindrical shape. The valve body 10 has a peripheral wall portion 11 and a bottom wall portion 12. The bottom wall portion 12 is connected to the lower end of the peripheral wall portion 11. A main valve core 20 is disposed inside the valve body 10. The main valve core 20 divides the inner space of the valve body 10 into a main valve chamber 13 and a back pressure chamber 14. The main valve chamber 13 is located below the main valve core 20, and the back pressure chamber 14 is located above the main valve core 20. The bottom wall portion 12 has a main valve port 15 and a main valve seat 16. The main valve port 15 extends through the bottom wall portion 12. The annular main valve seat 16 is disposed in the main valve chamber 13 to surround the main valve port 15. The main valve port 15 is connected to the main valve chamber 13 via the main valve seat 16. The peripheral wall portion 11 engages with an inlet connector pipe 17, which serves as an inlet passage. The inlet connector pipe 17 extends laterally through the peripheral wall portion 11 and is connected to the main valve chamber 13. The bottom wall portion 12 engages with the outlet connector pipe 18, which serves as the outlet passage. The outlet connector pipe 18 is connected to the main valve port 15.

[0055] The main valve core 20 is disposed inside the valve body 10 in a manner that allows it to move in the vertical direction (axis L direction). The main valve core 20 has a main valve core body 21 and a flange 22.

[0056] The main valve core body 21 has a cylindrical shape. The main valve core body 21 has a pilot passage 25. The pilot passage 25 extends vertically through the main valve core body 21. The pilot passage 25 connects the back pressure chamber 14 and the main valve port 15. A large-diameter portion 25a is provided at the lower part of the pilot passage 25. A small-diameter portion 25b, connected to the large-diameter portion 25a, is provided at the upper part of the pilot passage 25. The diameter of the small-diameter portion 25b is smaller than the diameter of the large-diameter portion 25a. The lower end of the main valve core body 21 is disposed in the main valve chamber 13. A main valve portion 21a is provided at the lower end of the main valve core body 21. The main valve portion 21a contacts and separates from the main valve seat 16. When the main valve portion 21a contacts the main valve seat 16, the main valve port 15 is closed. When the main valve portion 21a separates from the main valve seat 16, the main valve port 15 is opened. The upper end of the main valve core body 21 is disposed in the back pressure chamber 14. A circular pilot valve seat 21b is provided at the upper end of the main valve core body 21. The pilot valve seat 21b is configured to surround the pilot passage 25.

[0057] The flange 22 has an annular shape. The outer diameter of the flange 22 is larger than the outer diameter of the main valve core body 21. The flange 22 is coaxially connected to the main valve core body 21. The outer peripheral surface of the flange 22 slides along the inner peripheral surface of the peripheral wall portion 11. The flange 22 has a pressure equalization passage 26. The pressure equalization passage 26 extends through the flange 22 in the vertical direction. The pressure equalization passage 26 connects the main valve chamber 13 and the back pressure chamber 14. The gap between the outer peripheral surface of the flange 22 and the inner peripheral surface of the peripheral wall portion 11 is also a pressure equalization passage connecting the main valve chamber 13 and the back pressure chamber 14. In the following description, the gap between the outer peripheral surface of the flange 22 and the inner peripheral surface of the peripheral wall portion 11 and the pressure equalization passage 26 are collectively referred to as "pressure equalization passage 26E". Alternatively, the solenoid valve 1 may be a structure that omits the pressure equalization passage 26 and uses only the gap between the outer peripheral surface of the flange 22 and the inner peripheral surface of the peripheral wall portion 11 as the pressure equalization passage.

[0058] The drive unit 30 has a housing 31, a coil 32, a fixed iron core 33, a plunger 34, and a plunger spring 35.

[0059] The housing 31 has a cylindrical shape. The lower end of the housing 31 is mounted on the upper end of the peripheral wall portion 11. The coil 32 is disposed on the outside of the housing 31. The fixed iron core 33 has a cylindrical shape. The fixed iron core 33 is inserted into the upper end of the housing 31. The plunger 34 has a cylindrical shape. The plunger 34 is housed in the housing 31 and is movable in the vertical direction. The plunger spring 35 is disposed between the fixed iron core 33 and the plunger 34. The plunger spring 35 is a compression helical spring. The plunger spring 35 presses the plunger 34 downward.

[0060] The pilot valve core 40 has a spherical shape. The pilot valve core 40 is disposed in the back pressure chamber 14. The pilot valve core 40 is mounted to the lower end of the plunger 34 by riveting. Alternatively, the pilot valve core 40 can be welded to the lower end of the plunger 34. The pilot valve core 40 moves vertically via the drive unit 30. The pilot valve core 40 contacts and separates from the pilot valve seat 21b. When the pilot valve core 40 contacts the pilot valve seat 21b, the pilot passage 25 is closed. When the pilot valve core 40 separates from the pilot valve seat 21b, the pilot passage 25 is opened.

[0061] The flow path switching mechanism 60 is disposed in the pilot passage 25. The flow path switching mechanism 60 has a flow path switching valve core 61, a valve seat portion 62, and a pressure differential working spring 63.

[0062] The flow path switching valve core 61 is disposed in the large-diameter portion 25a of the pilot passage 25 in a manner that allows it to move in the vertical direction. The flow path switching valve core 61 has a cylindrical switching valve portion 61a and a cylindrical guide portion 61b coaxially connected to the upper end of the switching valve portion 61a. A first flow hole 61c extending in the vertical direction is provided at the lower end of the switching valve portion 61a. Multiple through holes 61d extending in the transverse direction are provided in the switching valve portion 61a. The upper end of the guide portion 61b is open. The outer diameter of the guide portion 61b is larger than the outer diameter of the switching valve portion 61a. The outer peripheral surface of the guide portion 61b slides along the inner peripheral surface of the large-diameter portion 25a of the pilot passage 25.

[0063] A valve seat portion 62 is disposed at the lower end of the pilot passage 25 (large diameter portion 25a). The valve seat portion 62 has an annular plate shape. A second flow hole 62c, extending vertically, is provided in the center of the valve seat portion 62. The diameter of the second flow hole 62c is larger than the diameter of the first flow hole 61c. The diameter of the second flow hole 62c is smaller than the diameter of the small diameter portion 25b of the pilot passage 25. Alternatively, the diameter of the second flow hole 62c may be larger than the diameter of the small diameter portion 25b of the pilot passage 25.

[0064] The flow area A2 of the second flow orifice 62c is larger than the flow area A1 of the first flow orifice 61c. The flow area Ae of the pressure equalization passage 26E is larger than the flow area A1 of the first flow orifice 61c and smaller than the flow area A2 of the second flow orifice 62c (A2>Ae>A1). Furthermore, the flow area is the cross-sectional area of ​​the narrowest part of the flow path. Although the fluid flow rate is actually determined by multiple factors such as the flow area and the pressure difference between the upstream and downstream sides of the flow path, for ease of explanation in this specification, it is assumed that a larger flow area results in a larger flow rate. To more accurately describe the flow rate of the fluid through the passages and orifices of the solenoid valve 1, when the flow rate of the pressure equalization passage 26E (flow area Ae) is set to Qe, the flow rate of the first flow orifice 61c (flow area A1) is set to Q1, and the flow rate of the second flow orifice 62c (flow area A2) is set to Q2, the solenoid valve 1 is configured such that the magnitudes of each flow rate are Q2>Qe>Q1.

[0065] A differential pressure working spring 63 is disposed between the guide portion 61b and the valve seat portion 62 of the flow path switching valve core 61. The differential pressure working spring 63 is a compression helical spring. The differential pressure working spring 63 presses the flow path switching valve core 61 upward. When there is no pressure difference between the upstream and downstream sides of the pilot passage 25, the differential pressure working spring 63 presses the flow path switching valve core 61 against the stepped portion, which is an annular plane provided inside the main valve core body 21.

[0066] In the flow path switching mechanism 60, when the pilot passage 25 is in an open state, if the pressure difference ΔP23 between the fluid pressure P2 in the back pressure chamber 14 on the upstream side of the pilot passage 25 and the fluid pressure P3 at the main valve port 15 on the downstream side is equal to or greater than a predetermined switching set value S1 (ΔP23≥S1), the force by which the fluid flowing in the pilot passage 25 presses the flow path switching spool 61 toward the downstream side is larger than the force by which the pressure difference working spring 63 presses the flow path switching spool 61 toward the upstream side. As a result, the flow path switching spool 61 moves toward the downstream side and comes into contact with the valve seat portion 62. Then, when the flow path switching spool 61 is in contact with the valve seat portion 62, the switching valve portion 61a closes the second communication hole 62c, so that the fluid flowing in the pilot passage 25 passes through the first communication hole 61c( Figure 3 ). The pilot passage 25 having a configuration in which fluid passes through the first communication hole 61c is referred to as "first passage mode F1". In the pilot passage 25 of the first passage mode F1, the first communication hole 61c is the narrowest, and the flow path area A1 of the first communication hole 61c is the flow path area of the pilot passage 25 in the first passage mode F1.

[0067] In the flow path switching mechanism 60, when the pilot passage 25 is in an open state, if the pressure difference ΔP23 is smaller than the predetermined switching set value S1 (ΔP23<S1), the force by which the fluid flowing in the pilot passage 25 presses the flow path switching spool 61 toward the downstream side is smaller than the force by which the pressure difference working spring 63 presses the flow path switching spool 61 toward the upstream side. As a result, the flow path switching spool 61 moves toward the upstream side and separates from the valve seat portion 62. Then, when the flow path switching spool 61 separates from the valve seat portion 62, the second communication hole 62c is opened, and the fluid flowing in the pilot passage 25 passes through the second communication hole 62c( Figure 4 ). The pilot passage 25 having a configuration in which fluid passes through the second communication hole 62c is referred to as "second passage mode F2". In the pilot passage 25 of the second passage mode F2, the second communication hole 62c is the narrowest, and the flow path area A2 of the second communication hole 62c is the flow path area of the pilot passage 25 in the second passage mode F2. Further, in a configuration where the diameter of the second communication hole 62c is larger than the diameter of the small diameter portion 25b of the pilot passage 25, the flow path area of the small diameter portion 25b is the flow path area of the pilot passage 25 in the second passage mode F2.

[0068] In the solenoid valve 1, the respective axes of the valve main body 10 (the peripheral wall portion 11, the main valve port 15, and the main valve seat 16), the main spool 20 (the main spool main body 21, the main valve portion 21a, the pilot valve seat 21b, the flange 22, and the pilot passage 25), the housing 31, the coil 32, the plunger 34, the pilot spool 40, and the flow path switching mechanism 60 (the flow path switching spool 61 and the valve seat portion 62) are aligned with the axis line L.

[0069] Next, referring to Figures 2-5An example of the operation of the solenoid valve 1 will be described.

[0070] When the coil 32 is in a non-energized state, the plunger 34 moves downward via the plunger spring 35. The plunger 34 presses the pilot valve element 40 against the pilot valve seat 21b of the main valve element 20, so that the pilot valve element 40 closes the pilot passage 25. Furthermore, the pilot valve element 40 presses the main valve element 20 (main valve portion 21a) against the main valve seat 16, so that the main valve element 20 closes the main valve port 15. As a result, the flow of fluid from the main valve chamber 13 to the main valve port 15 is blocked, as Figure 2 shown, the solenoid valve 1 is in a valve-closed state. In the valve-closed state, the fluid pressure P1 in the main valve chamber 13 is the same as the fluid pressure P2 in the back pressure chamber 14 (P1≈P2). In addition, the fluid pressure P3 at the main valve port 15 is lower than the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14.

[0071] Further, when the coil 32 is brought into an energized state, the plunger 34 moves upward via magnetic force. As Figure 3 shown, the plunger 34 separates the pilot valve element 40 from the pilot valve seat 21b of the main valve element 20, so that the pilot passage 25 is opened. At this time, since the pressure difference ΔP23 between the fluid pressure P2 in the back pressure chamber 14 and the fluid pressure P3 at the main valve port 15 is large (ΔP23≥S1), the flow path switching spool 61 is pressed by the fluid flowing in the pilot passage 25 to move downward and comes into contact with the valve seat portion 62. As a result, the fluid flowing in the pilot passage 25 flows toward the main valve port 15 through the first communication hole 61c with a small flow path area. That is, the flow path switching mechanism 60 switches the pilot passage 25 to the first passage mode F1.

[0072] When the fluid in the back pressure chamber 14 flows toward the main valve port 15 through the first communication hole 61c, the flow rate between the back pressure chamber 14 and the main valve port 15 is smaller than the flow rate between the main valve chamber 13 and the back pressure chamber 14. Therefore, the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 are maintained at substantially the same value and gradually decrease. Then, when the fluid pressure P2 in the back pressure chamber 14 decreases and the pressure difference ΔP23 becomes small (ΔP23<S1), the force with which the fluid flowing in the pilot passage 25 presses the flow path switching spool 61 downward weakens, as Figure 4 shown, the flow path switching spool 61 is pressed by the pressure difference operating spring 63 to move upward and separates from the valve seat portion 62. As a result, the fluid flowing in the pilot passage 25 flows toward the main valve port 15 through the second communication hole 62c with a large flow path area. That is, the flow path switching mechanism 60 switches the pilot passage 25 to the second passage mode F2.

[0073] When the fluid in the back pressure chamber 14 flows to the main valve port 15 through the second flow hole 62c, the flow rate between the back pressure chamber 14 and the main valve port 15 is greater than the flow rate between the main valve chamber 13 and the back pressure chamber 14. Therefore, the fluid pressure P2 in the back pressure chamber 14 is less than the fluid pressure P1 in the main valve chamber 13 (P1>P2), and the fluid pressure P2 in the back pressure chamber 14 is almost the same as the fluid pressure P3 in the main valve port 15 (P2≈P3). Thus, the pressure difference ΔP12 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 applies an upward pressing force to the main valve core 20, such as... Figure 5 As shown, the main valve core 20 separates from the main valve seat 16, and the main valve port 15 opens. At this time, since the pressure difference ΔP13 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P3 in the main valve port 15 is smaller than when the pilot passage 25 is just opened, it is possible to suppress the rapid flow of fluid from the main valve chamber 13 into the main valve port 15.

[0074] As described above, the solenoid valve 1 includes: a valve body 10 having a main valve chamber 13 and a back pressure chamber 14; a main valve core 20 configured to divide the main valve chamber 13 and the back pressure chamber 14, and to open and close a main valve port 15 connected to the main valve chamber 13; a pressure equalization passage 26E connecting the main valve chamber 13 and the back pressure chamber 14; a pilot passage 25 connecting the back pressure chamber 14 and the main valve port 15; a pilot valve core 40 opening and closing the pilot passage 25; and a drive unit 30 driving the pilot valve core 40. The solenoid valve 1 also includes a fluid switching mechanism 60 that switches the pilot passage 25 to a first passage mode F1 with a flow area smaller than that of the pressure equalization passage 26E and a second passage mode F2 with a flow area larger than that of the pressure equalization passage 26E. Furthermore, the flow path switching mechanism 60 is configured such that, when the pilot passage 25 is open, it switches to the first passage mode F1 when the pressure difference ΔP23 between the fluid pressure P2 in the back pressure chamber 14 and the fluid pressure P3 in the main valve port 15 is large, and switches to the second passage mode F2 when the pressure difference ΔP23 is small.

[0075] In solenoid valve 1, when the main valve port 15 is closed, the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 are the same (or nearly the same), while the fluid pressure P3 in the main valve port 15 is lower than these fluid pressures P1 and P2. Therefore, when the pilot passage 25 is just opened, the pressure difference ΔP23 is relatively large. The flow path switching mechanism 60 switches the pilot passage 25 to a first passage mode F1 with a smaller flow path area, making the flow rate between the back pressure chamber 14 and the main valve port 15 smaller than the flow rate between the main valve chamber 13 and the back pressure chamber 14. As a result, the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P3 in the back pressure chamber 14 remain nearly the same and gradually decrease. Furthermore, when the pressure difference ΔP23 decreases, the flow path switching mechanism 60 switches the pilot passage 25 to a second passage mode F2 with a larger flow path area, making the flow rate between the back pressure chamber 14 and the main valve port 15 larger than the flow rate between the main valve chamber 13 and the back pressure chamber 14. As a result, the fluid pressure P2 in the back pressure chamber 14 becomes lower than the fluid pressure P1 in the main valve chamber 13. Due to the pressure difference ΔP12 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14, the main valve core 20 separates from the main valve seat 16, thereby opening the main valve port 15. At this time, the pressure difference ΔP13 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P3 in the main valve port 15 is smaller than when the pilot passage 25 was just opened. Therefore, the rapid flow of fluid from the main valve chamber 13 to the main valve port 15 can be suppressed, effectively suppressing the noise generated when the main valve port 15 opens.

[0076] Furthermore, the flow path switching mechanism 60 includes: a flow path switching valve core 61 with a first flow hole 61c; a valve seat portion 62 with a second flow hole 62c having a diameter larger than the first flow hole 61c; and a pressure differential working spring 63 configured to press the flow path switching valve core 61 upstream (towards the back pressure chamber 14). In the flow path switching mechanism 60, the flow path switching valve core 61 contacts and separates from the valve seat portion 62 based on the pressure difference ΔP23 between the fluid pressure P2 in the upstream back pressure chamber 14 and the fluid pressure P3 in the downstream main valve port 15. The flow path switching mechanism 60 is configured such that when the flow path switching valve core 61 contacts the valve seat portion 62, the fluid flowing in the pilot passage 25 passes through the first flow hole 61c; and when the flow path switching valve core 61 separates from the valve seat portion 62, the fluid flowing in the pilot passage 25 passes through the second flow hole 62c. Therefore, the pressure difference ΔP23 can be used to allow fluid to pass through either the small-diameter first flow hole 61c or the large-diameter second flow hole 62c, thereby switching between the first flow path mode F1 and the second flow path mode F2. Thus, the flow path switching mechanism 60 can have a relatively simple structure.

[0077] (Second Embodiment)

[0078] The following is for reference Figures 6-10A pilot-operated solenoid valve according to a second embodiment of the electrically driven valve of the present invention will be described.

[0079] Figure 6 This is a cross-sectional view of the solenoid valve according to the second embodiment of the present invention. Figures 7-10 yes Figure 6 An enlarged sectional view of the valve body and its surrounding area of ​​the solenoid valve. Figures 7-10 The states are sequentially represented as closed valve state, intermediate state 1 (the pressure equalization path is in the second path mode), intermediate state 2 (the pressure equalization path is in the first path mode), and open valve state. In the following description, the same symbols are used for components that are the same as (including substantially the same as) the solenoid valve 1 in the first embodiment, and the description is omitted.

[0080] like Figures 6-10 As shown, the solenoid valve 2 of the second embodiment includes a valve body 10, a main valve core 20, a drive unit 30, a pilot valve core 40, and a flow path switching mechanism 70. The solenoid valve 2 has a flow path switching mechanism 70 with a different structure than the flow path switching mechanism 60 of the solenoid valve 1 described above.

[0081] The flow path switching mechanism 70 is disposed in the pressure equalization passage 26. The flow path switching mechanism 70 has a flow path switching valve core 71, a valve seat portion 72, and a pressure differential working spring 73.

[0082] The flow path switching valve core 71 is disposed in the pressure equalization passage 26 in a manner that allows it to move in the vertical direction. The flow path switching valve core 71 has a cylindrical switching valve portion 71a and multiple guide portions 71b protruding from the outer peripheral surface of the switching valve portion 71a. A first flow hole 71c extending in the vertical direction is provided at the lower end of the switching valve portion 71a. Multiple through holes 71d extending in the transverse direction are provided in the switching valve portion 71a. The upper end of the switching valve portion 71a is open. The diameter of the circle imaginarily connecting the top ends of the guide portions 71b is larger than the outer diameter of the switching valve portion 71a. The top ends of the guide portions 71b slide along the inner peripheral surface of the pressure equalization passage 26.

[0083] A valve seat portion 72 is disposed at the lower end of the pressure equalization passage 26. The valve seat portion 72 has an annular plate shape. The valve seat portion 72 is integrally formed with the main valve core 20. A second flow hole 72c, extending vertically, is provided in the center of the valve seat portion 72. The diameter of the second flow hole 72c is larger than the diameter of the first flow hole 71c.

[0084] The flow path area B2 of the second flow orifice 72c is larger than the flow path area B1 of the first flow orifice 71c. The flow path area Bp of the pilot passage 25 is larger than the flow path area B1 of the first flow orifice 71c and smaller than the flow path area B2 of the second flow orifice 72c (B2 > Bp > B1). Furthermore, the flow path area refers to the cross-sectional area of ​​the narrowest part of the flow path. When the flow rate of the pilot passage 25 (flow path area Bp) is set to Qp, the flow rate of the first flow orifice 71c (flow path area B1) is set to Q1, and the flow rate of the second flow orifice 72c (flow path area B2) is set to Q2, the solenoid valve 2 is configured such that the magnitudes of the flow rates are Q2 > Qp > Q1.

[0085] A differential pressure working spring 73 is disposed between the guide portion 71b of the flow path switching valve core 71 and the annular plate-shaped spring support member 74 disposed at the upper end of the pressure equalization passage 26. The differential pressure working spring 73 is a compression helical spring. The differential pressure working spring 73 presses the flow path switching valve core 71 downward. When there is no pressure difference between the upstream and downstream sides of the pressure equalization passage 26, the differential pressure working spring 73 presses the flow path switching valve core 71 against the valve seat portion 72.

[0086] In the flow path switching mechanism 70, when the pilot passage 25 is open, when the pressure difference ΔP12 between the fluid pressure P1 in the main valve chamber 13 upstream of the equalizing passage 26 and the fluid pressure P2 in the back pressure chamber 14 downstream is small, or when the pressure difference ΔP12 is large and the pressure difference ΔP23 between the fluid pressure P2 in the back pressure chamber 14 and the fluid pressure P3 in the main valve port 15 is small, the force by which the fluid flowing in the equalizing passage 26 presses the flow path switching valve core 71 downstream is less than the force by which the pressure difference working spring 73 presses the flow path switching valve core 71 upstream. As a result, the flow path switching valve core 71 moves upstream and contacts the valve seat portion 72. Then, when the flow path switching valve core 71 contacts the valve seat portion 72, the switching valve portion 71a closes the second flow hole 72c, and the fluid flowing in the equalizing passage 26 passes through the first flow hole 71c ( Figure 9 The pressure equalization passage 26E that allows fluid to pass through the first flow hole 71c is referred to as "first passage mode G1". The area of ​​the pressure equalization passage 26E of the first passage mode G1 is the sum of the cross-sectional area of ​​the gap between the outer peripheral surface of the flange 22 and the inner peripheral surface of the peripheral wall portion 11 and the flow path area B1 of the first flow hole 71c. The flow path area of ​​the pressure equalization passage 26E of the first passage mode G1 is smaller than the flow path area of ​​the pilot passage 25.

[0087] In the flow path switching mechanism 70, when the pilot passage 25 is open, and both the pressure difference ΔP12 and ΔP23 are large, the force by which the fluid flowing in the equalizing passage 26 presses the flow path switching valve core 71 downstream is greater than the force by which the pressure difference working spring 73 presses the flow path switching valve core 71 upstream. As a result, the flow path switching valve core 71 moves downstream and separates from the valve seat 72. Then, when the flow path switching valve core 71 separates from the valve seat 72, the second flow hole 72c opens, and the fluid flowing in the equalizing passage 26 passes through the second flow hole 72c. Figure 8 The pressure equalization passage 26E that allows fluid to pass through the second flow hole 72c is called "second passage mode G2". The area of ​​the pressure equalization passage 26E of the second passage mode G2 is the sum of the cross-sectional area of ​​the gap between the outer peripheral surface of the flange 22 and the inner peripheral surface of the peripheral wall portion 11 and the flow path area B2 of the second flow hole 72c. The flow path area of ​​the pressure equalization passage 26E of the second passage mode G2 is larger than the flow path area of ​​the pilot passage 25.

[0088] Next, refer to Figures 7-10 An example of the operation of solenoid valve 2 will be explained.

[0089] When coil 32 is not energized, similar to solenoid valve 1, solenoid valve 2 is in a closed state. Figure 7 ).

[0090] Furthermore, when coil 32 is energized, plunger 34 moves upward by magnetic force. For example... Figure 8 As shown, the plunger 34 separates the pilot valve core 40 from the pilot valve seat 21b of the main valve core 20, thereby opening the pilot passage 25. When the pilot passage 25 is just opened, the pressure difference ΔP23 between the fluid pressure P2 in the back pressure chamber 14 and the fluid pressure P3 in the main valve port 15 is large, and fluid flows from the back pressure chamber 14 to the main valve port 15, and the pressure difference ΔP12 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 increases. At this time, the flow rate of the fluid flowing in the equalizing passage 26 increases, and the flow path switching valve core 71 is pressed upward by the fluid and separates from the valve seat portion 72. As a result, the fluid flowing in the equalizing passage 26 flows to the back pressure chamber 14 through the second flow hole 72c with a larger flow area. That is, the flow path switching mechanism 70 switches the equalizing passage 26E to the second passage mode G2.

[0091] When the fluid in the main valve chamber 13 flows to the back pressure chamber 14 through the second flow hole 72c, the flow rate between the main valve chamber 13 and the back pressure chamber 14 becomes greater than the flow rate between the back pressure chamber 14 and the main valve port 15. Therefore, the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 gradually decrease and approach each other, thus reducing the pressure difference ΔP12. Furthermore, as the pressure difference ΔP12 decreases, the flow rate of the fluid flowing in the equalizing passage 26 decreases, thereby weakening the force by which the fluid presses the flow path switching valve core 71 upwards. Figure 9 As shown, the flow path switching valve core 71 moves downward and contacts the valve seat portion 72. Consequently, the fluid flowing in the equalizing passage 26 flows towards the back pressure chamber 14 through the first flow hole 71c, which has a smaller flow path area. That is, the flow path switching mechanism 70 switches the equalizing passage 26E to the first passage mode G1.

[0092] When the fluid in the main valve chamber 13 flows to the back pressure chamber 14 through the first flow hole 71c, the flow rate between the main valve chamber 13 and the back pressure chamber 14 becomes smaller than the flow rate between the back pressure chamber 14 and the main valve port 15. Therefore, compared to the fluid pressure P1 in the main valve chamber 13, the fluid pressure P2 in the back pressure chamber 14 decreases, the pressure difference ΔP12 increases (P1>P2) and the pressure difference ΔP23 decreases (P2≈P3), and the flow rate of the fluid flowing in the equalizing passage 26 decreases, so the flow path switching valve core 71 remains in contact with the valve seat portion 72. Thus, the pressure difference ΔP12 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 applies an upward pressing force to the main valve core 20, such as... Figure 10 As shown, the main valve core 20 separates from the main valve seat 16, thereby opening the main valve port 15. At this time, since the pressure difference ΔP13 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P3 in the main valve port 15 is smaller than when the pilot passage 25 is just opened, it is possible to suppress the rapid flow of fluid from the main valve chamber 13 into the main valve port 15.

[0093] As described above, the solenoid valve 2 includes: a valve body 10 having a main valve chamber 13 and a back pressure chamber 14; a main valve core 20 configured to divide the main valve chamber 13 and the back pressure chamber 14, and to open and close a main valve port 15 connected to the main valve chamber 13; a pressure equalization passage 26E connecting the main valve chamber 13 and the back pressure chamber 14; a pilot passage 25 connecting the back pressure chamber 14 and the main valve port 15; a pilot valve core 40 opening and closing the pilot passage 25; and a drive unit 30 driving the pilot valve core 40. The solenoid valve 2 also includes a fluid switching mechanism 70 that switches the pressure equalization passage 26E to a first passage mode G1 with a flow area smaller than that of the pilot passage 25 and a second passage mode G2 with a flow area larger than that of the pilot passage 25. Furthermore, the flow path switching mechanism 70 is configured such that when the pilot passage 25 is open, it switches to the second passage mode G2 when the pressure difference ΔP12 is large and the pressure difference ΔP23 is large, and switches to the first passage mode G1 when the pressure difference ΔP12 is small or the pressure difference ΔP12 is large and the pressure difference ΔP23 is small.

[0094] In solenoid valve 2, when the main valve port 15 is closed, the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 are the same (or almost the same), while the fluid pressure P3 in the main valve port 15 is lower than these fluid pressures P1 and P2. Therefore, when the pilot passage 25 is just opened, the pressure difference ΔP23 is large, and the fluid flows from the back pressure chamber 14 to the main valve port 15, increasing the pressure difference ΔP12. At this time, the flow path switching mechanism 70 switches the pressure equalization passage 26E to the second passage mode G2 with a larger flow area, making the flow rate between the main valve chamber 13 and the back pressure chamber 14 greater than the flow rate between the back pressure chamber 14 and the main valve port 15. As a result, the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P2 in the back pressure chamber 14 gradually decrease and approach each other, and the pressure difference ΔP12 decreases. Then, when the pressure difference ΔP12 decreases, the flow path switching mechanism 70 switches the pressure equalization passage 26E to the first passage mode G1 with a smaller flow area, making the flow rate between the main valve chamber 13 and the back pressure chamber 14 smaller than the flow rate between the back pressure chamber 14 and the main valve port 15. As a result, compared to the fluid pressure P1 in the main valve chamber 13, the fluid pressure P2 in the back pressure chamber 14 decreases, thus increasing the pressure difference ΔP12 and decreasing the pressure difference ΔP23. Then, through the pressure difference ΔP12, the main valve core 20 separates from the main valve seat 16, thereby opening the main valve port 15. At this time, the pressure difference ΔP13 between the fluid pressure P1 in the main valve chamber 13 and the fluid pressure P3 in the main valve port 15 is smaller than when the pilot passage 25 just opened. Therefore, it is possible to suppress the rapid inflow of fluid from the main valve chamber 13 into the main valve port 15, thereby effectively suppressing the noise generated when the main valve port 15 opens.

[0095] Furthermore, the flow path switching mechanism 70 includes: a flow path switching valve core 71 with a first flow hole 71c; a valve seat portion 72 with a second flow hole 72c having a diameter larger than the first flow hole 71c; and a pressure differential working spring 73 configured to press the flow path switching valve core 71 upstream. In the flow path switching mechanism 70, the flow path switching valve core 71 contacts and separates from the valve seat portion 72 based on the pressure difference ΔP12 between the fluid pressure P1 in the upstream main valve chamber 13 and the fluid pressure P2 in the downstream back pressure chamber 14, and the pressure difference ΔP23 between the fluid pressure P2 in the back pressure chamber 14 and the fluid pressure P3 in the main valve port 15. Moreover, the flow path switching mechanism 70 is configured such that when the flow path switching valve core 71 contacts the valve seat portion 72, fluid flows through the first flow hole 71, and when the flow path switching valve core 71 separates from the valve seat portion 72, fluid flows through the second flow hole 72c. Therefore, by utilizing pressure differences ΔP12 and ΔP23, fluid can be directed through either the small-diameter first flow orifice 71c or the large-diameter second flow orifice 72c, thereby switching between the first flow path mode G1 and the second flow path mode G2. This allows for a relatively simple structure in the flow path switching mechanism 70.

[0096] (Third Embodiment)

[0097] The following is for reference Figures 11-16 A pilot-operated solenoid valve according to a third embodiment of the electrically driven valve of the present invention will be described.

[0098] Figure 11 This is a cross-sectional view of the solenoid valve according to the third embodiment of the present invention. Figure 12 It is along Figure 11 A sectional view of line XII-XII. Figures 13-16 It means Figure 11 A cross-sectional view of a portion of a solenoid valve. Figures 13-16 In the diagram, (a) is a sectional view of the main valve core and its interior, and (b) is an enlarged sectional view of the portion enclosed by the dashed line in (a). Figures 13-16 The states are sequentially represented as follows: the second main valve port closed, intermediate state 1 (the second pilot path is in the first path mode), intermediate state 2 (the second pilot path is in the second path mode), and the second main valve port open. Figure 13 , Figure 16 In the diagram, arrows are used to symbolically represent the flow of fluid.

[0099] like Figures 11-15 As shown, the electric valve 3 of the third embodiment includes a valve body 110, a first main valve core 120, a drive unit 130, a first pilot valve core 140, a second main valve core 220, a second pilot valve core 240, and a flow path switching mechanism 260.

[0100] The valve body 110 has a first space 110a, a second space 110b, an inlet flow path 110c, an intermediate flow path 110d, and an outlet flow path 110e.

[0101] A first main valve core 120 is disposed in a first space 110a. The first main valve core 120 divides the first space 110a into a first main valve chamber 113 and a first back pressure chamber 114. The first main valve chamber 113 is located below the first main valve core 120, and the first back pressure chamber 114 is located above the first main valve core 120. A first main valve port 115 and a first main valve seat 116 are disposed on the bottom surface of the first space 110a. The first main valve port 115 extends in the vertical direction. The annular first main valve seat 116 is disposed in the first main valve chamber 113 to surround the first main valve port 115. The first main valve port 115 is connected to the first main valve chamber 113 via the first main valve seat 116. An inlet flow path 110c is connected to the first main valve chamber 113. An intermediate flow path 110d is connected to the first main valve port 115.

[0102] A second main valve core 220 is disposed in the second space 110b. The second main valve core 220 divides the second space 110b into a second main valve chamber 213 and a second back pressure chamber 214. The second main valve chamber 213 is located below the second main valve core 220, and the second back pressure chamber 214 is located above the second main valve core 220. A second main valve port 215 and a second main valve seat 216 are disposed on the bottom surface of the second space 110b. The second main valve port 215 extends in the vertical direction. The annular second main valve seat 216 is disposed in the second main valve chamber 213 to surround the second main valve port 215. The second main valve port 215 is connected to the second main valve chamber 213 via the second main valve seat 216. An intermediate flow path 110d is connected to the second main valve chamber 213. An outlet flow path 110e is connected to the second main valve port 215. In the second back pressure chamber 214, a valve closing spring 235 is disposed between the valve body 110 and the second main valve core 220. The valve closing spring 235 is a compression helical spring. The valve closing spring 235 presses the second main valve core 220 downward.

[0103] The first main valve core 120 is disposed in the first space 110a in a manner that allows it to move in the vertical direction (axis L direction). The first main valve core 120 has a first main valve core body 121 and a first flange 122.

[0104] The first main valve core body 121 has a cylindrical shape. The first main valve core body 121 has a first pilot passage 125. The first pilot passage 125 extends vertically through the first main valve core body 121. The upper end of an actuating rod 128 is inserted into the lower end of the first pilot passage 125. The first pilot passage 125 connects the first back pressure chamber 114 and the first main valve port 115 via a fluid passage 128a located at the upper end of the actuating rod 128. The lower end of the first main valve core body 121 is disposed in the first main valve chamber 113. A first main valve portion 121a is provided at the lower end of the first main valve core body 121. The first main valve portion 121a contacts and separates from the first main valve seat 116. When the first main valve portion 121a contacts the first main valve seat 116, the first main valve port 115 is closed. When the first main valve portion 121a separates from the first main valve seat 116, the first main valve port 115 is opened. The upper end of the first main valve core body 121 is disposed in the first back pressure chamber 114. A first pilot valve seat 121b in the shape of an annulus is provided at the upper end of the first main valve core body 121. The first pilot valve seat 121b is configured to surround the first pilot passage 125.

[0105] The first flange 122 has an annular shape. The outer diameter of the first flange 122 is larger than the outer diameter of the first main valve core body 121. The first flange 122 is coaxially connected to the first main valve core body 121. The outer peripheral surface of the first flange 122 slides along the inner peripheral surface of the first space 110a. The first flange 122 has a first pressure equalization passage 126. The first pressure equalization passage 126 extends through the first flange 122 in the vertical direction. The first pressure equalization passage 126 connects the first main valve chamber 113 and the first back pressure chamber 114. The gap between the outer peripheral surface of the first flange 122 and the inner peripheral surface of the first space 110a is also the first pressure equalization passage connecting the first main valve chamber 113 and the first back pressure chamber 114.

[0106] The drive unit 130 includes a housing 31, a coil 32, a fixed iron core 33, a plunger 34, and a plunger spring 35. Since these components have the same (including substantially the same) structure as the solenoid valve 1 described above, they are labeled with the same symbols and descriptions are omitted. Furthermore, since the first pilot valve core 140 also has the same structure as the pilot valve core 40 of the solenoid valve 1 described above, descriptions are omitted.

[0107] The second main valve core 220 is disposed in the second space 110b in a manner that allows it to move in the vertical direction. The second main valve core 220 has a second main valve core body 221 and a second flange 222.

[0108] The second main valve core body 221 has a cylindrical shape. The lower end of the second main valve core body 221 is disposed in the second main valve chamber 213. A second main valve portion 221a is provided at the lower end of the second main valve core body 221. The second main valve portion 221a contacts and separates from the second main valve seat 216. When the second main valve portion 221a contacts the second main valve seat 216, the second main valve port 215 is closed. When the second main valve portion 221a separates from the second main valve seat 216, the second main valve port 215 is opened. The upper end of the second main valve core body 221 is disposed in the second back pressure chamber 214. The second main valve core body 221 has a second pressure equalization passage 226. The second pressure equalization passage 226 has an inverted T-shape with openings on the upper surface and outer peripheral surface of the second main valve core body 221. The second pressure equalization passage 226 connects the second main valve chamber 213 and the second back pressure chamber 214.

[0109] The second flange 222 has an annular shape. The outer diameter of the second flange 222 is larger than the outer diameter of the second main valve core body 221. The second flange 222 is coaxially connected to the second main valve core body 221. The outer peripheral surface of the second flange 222 slides along the inner peripheral surface of the second space 110b. The gap between the outer peripheral surface of the second flange 222 and the inner peripheral surface of the second space 110b is also the second pressure equalization passage connecting the second main valve chamber 213 and the second back pressure chamber 214. In the following description, the gap between the outer peripheral surface of the second flange 222 and the inner peripheral surface of the second space 110b and the second pressure equalization passage 226 are collectively referred to as "second pressure equalization passage 226E". Alternatively, the solenoid valve 3 may omit the second pressure equalization passage 226 and use only the gap between the outer peripheral surface of the second flange 222 and the inner peripheral surface of the second space 110b as the second pressure equalization passage.

[0110] In addition, the valve body 110 has a third space 110f, an actuating rod insertion hole 110g, and a second pilot passage 225.

[0111] A second pilot valve core 240 is disposed in the third space 110f. The second pilot valve core 240 divides the third space 110f into a second pilot valve chamber 228 and a spring chamber 229. The second pilot valve chamber 228 is located on the upper side of the second pilot valve core 240, and the spring chamber 229 is located on the lower side of the second pilot valve core 240.

[0112] The second pilot valve core 240 is disposed in the third space 110f in a manner that allows it to move vertically. The second pilot valve core 240 has a frame 241 and a gasket 242. The frame 241 has a circular plate shape. The outer peripheral surface of the frame 241 slides along the inner peripheral surface of the third space 110f. The gasket 242 has an annular shape. The gasket 242 is riveted to the upper surface of the frame 241. The gasket 242 contacts and separates from the top surface 228a of the second pilot valve chamber 228.

[0113] The lower end of the actuating rod 128 protrudes from the top surface 228a of the second pilot valve chamber 228. The upper end of the actuating rod 128 is inserted into the first pilot passage 125 of the first main valve core 120. The actuating rod 128 is configured to span the first main valve port 115, the intermediate flow path 110d, the actuating rod insertion hole 110g, and the second pilot valve chamber 228. The lower end of the actuating rod 128 contacts the upper surface of the frame 241. The actuating rod 128 moves together with the first main valve core 120 in the vertical direction. When moving downward, the actuating rod 128 presses the second pilot valve core 240 downward. A valve-closing spring 245 is disposed in the spring chamber 229 between the second pilot valve core 240 and the valve body 110. The valve-closing spring 245 is a compression helical spring. The valve-closing spring 245 presses the second pilot valve core 240 upward.

[0114] The second pilot passage 225 has a front half 225a and a rear half 225b. The front half 225a connects the second back pressure chamber 214 and the second pilot valve chamber 228. The rear half 225b connects the second pilot valve chamber 228 and the outlet flow path 110e (i.e., the second main valve port 215). That is, the second pilot passage 225 connects the second back pressure chamber 214 and the second main valve port 215 via the second pilot valve chamber 228. A second pilot valve seat 228b is provided on the top surface 228a of the second pilot valve chamber 228. The second pilot valve seat 228b is configured to surround the rear half 225b of the passage.

[0115] like Figure 12 As shown, the first half of the passage 225a opens at the contact area 228c of the top surface 228a, away from the gasket 242. The second half of the passage 225b (second pilot valve seat 228b) opens at the contact area 228c of the top surface 228a, which contacts the gasket 242. The gasket 242 contacts and separates from the second pilot valve seat 228b to open and close the second pilot passage 225 (second half of the passage 225b). The first half of the passage 225a is always open relative to the second pilot valve chamber 228.

[0116] The flow path switching mechanism 260 is disposed in the rear half 225b of the second pilot passage 225. The flow path switching mechanism 260 includes a flow path switching valve core 61, a valve seat portion 62, and a pressure differential working spring 63. Since these components have the same (including substantially the same) structure as the flow path switching valve core 61, valve seat portion 62, and pressure differential working spring 63 of the solenoid valve 1 described above, the same symbols are used and some descriptions are omitted.

[0117] The flow path area A2 of the second communication hole 62c is larger than the flow path area A1 of the first communication hole 61c. The flow path area Ae2 of the second pressure equalizing passage 226E is larger than the flow path area A1 of the first communication hole 61c and smaller than the flow path area A2 of the second communication hole 62c (A2>Ae2>A1). In addition, the flow path area refers to the cross-sectional area of the narrowest portion of the flow path. When the flow rate of the second pressure equalizing passage 226E (flow path area Ae2) is defined as Qe2, the flow rate of the first communication hole 61c (flow path area A1) is defined as Q1, and the flow rate of the second communication hole 62c (flow path area A2) is defined as Q2, the solenoid valve 3 is configured such that the magnitudes of the respective flow rates satisfy Q2>Qe2>Q1.

[0118] In the flow path switching mechanism 260, when the second pilot passage 225 is in an open state, if the pressure difference ΔP23 between the fluid pressure P2 of the second back pressure chamber 214 on the upstream side of the second pilot passage 225 and the fluid pressure P3 of the second main valve port 215 on the downstream side is equal to or greater than a prescribed switching set value S1 (ΔP23≥S1), the force of the fluid flowing in the second pilot passage 225 pressing the flow path switching spool 61 toward the downstream side is larger than the force of the pressure difference working spring 63 pressing the flow path switching spool 61 toward the upstream side. As a result, the flow path switching spool 61 moves toward the downstream side and comes into contact with the valve seat portion 62. Then, when the flow path switching spool 61 comes into contact with the valve seat portion 62, the switching valve portion 61a closes the second communication hole 62c, so that the fluid flowing in the second pilot passage 225 passes through the first communication hole 61c( Figure 14 ). The second pilot passage 225 having the configuration in which the fluid passes through the first communication hole 61c is referred to as "first passage mode F1". In the second pilot passage 225 of the first passage mode F1, the first communication hole 61c is the narrowest, so the flow path area A1 of the first communication hole 61c becomes the flow path area of the second pilot passage 225 in the first passage mode F1.

[0119] In the flow path switching mechanism 260, when the second pilot passage 225 is in an open state, if the pressure difference ΔP23 is smaller than the prescribed switching set value S1 (ΔP23<S1), the force of the fluid flowing in the second pilot passage 225 pressing the flow path switching spool 61 toward the downstream side is smaller than the force of the pressure difference working spring 63 pressing the flow path switching spool 61 toward the upstream side. As a result, the flow path switching spool 61 moves toward the upstream side and separates from the valve seat portion 62. Then, when the flow path switching spool 61 separates from the valve seat portion 62, the second communication hole 62c is opened, and the fluid flowing in the second pilot passage 225 passes through the second communication hole 62c( Figure 15The second pilot passage 225 through which fluid passes through the second flow hole 62c is called "second passage mode F2". In the second pilot passage 225 of the second passage mode F2, the second flow hole 62c is the narrowest, so the flow area A2 of the second flow hole 62c becomes the flow area of ​​the second pilot passage 225 of the second passage mode F2.

[0120] In the solenoid valve 3, the valve body 110 (first space 110a, third space 110f, actuating rod insertion hole 110g, first main valve port 115, first main valve seat 116, second pilot valve chamber 228), the first main valve core 120 (first main valve core body 121, first main valve part 121a, first pilot valve seat 121b, first flange 122, first pilot passage 125), the actuating rod 128, the housing 31, the coil 32, the plunger 34, the first pilot valve core 140, and the second pilot valve core 240 each have their axes aligned with the axis L.

[0121] Next, refer to Figures 13-16 An example of the operation of solenoid valve 3 will be explained.

[0122] When coil 32 is energized, plunger 34 moves upward by magnetic force. Due to the pressure difference between the fluid pressure in the first main valve chamber 113 and the fluid pressure in the first back pressure chamber 114, the first main valve core 120 (first main valve portion 121a) separates from the first main valve seat 116, thereby opening the first main valve port 115. Actuator 128 moves upward together with the first main valve core 120. The second pilot valve core 240 is pressed against the second pilot valve seat 228b by the closing spring 245, thereby closing the second pilot passage 225. The fluid pressure P2 in the second back pressure chamber 214 becomes the same as the fluid pressure P1 in the second main valve chamber 213. The second main valve core 220 (second main valve portion 221a) is pressed against the second main valve seat 216 by the closing spring 235, thereby closing the second main valve port 215. Thus, as... Figure 13 As shown, solenoid valve 3 is in a state where the first main valve port 115 is open and the second main valve port 215 is closed. In this state, fluid enters from the inlet flow path 110c, passes through the first main valve chamber 113 and the first main valve port 115, and flows out from the intermediate flow path 110d. Furthermore, the fluid pressure P1 in the second main valve chamber 213 is the same as the fluid pressure P2 in the second back pressure chamber 214 (P1≈P2). Additionally, the fluid pressure P3 in the second main valve port 215 is lower than the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P2 in the second back pressure chamber 214.

[0123] Further, when the coil 32 is in a non-energized state, the plunger 34 is moved downward by the plunger spring 35. The plunger 34 presses the first pilot valve element 140 against the first pilot valve seat 121b, so that the first pilot valve element 140 closes the first pilot passage 125. Moreover, the first pilot valve element 140 presses the first main valve element 120 (the first main valve portion 121a) against the first main valve seat 116, so that the first main valve element 120 closes the first main valve port 115. As a result, the flow of fluid from the first main valve chamber 113 to the first main valve port 115 is shut off.

[0124] In addition, the operation rod 128 moves downward together with the first main valve element 120, and the operation rod 128 presses the second pilot valve element 240 downward. As a result, the second pilot valve element 240 is separated from the second pilot valve seat 228b, so that the second pilot passage 225 is opened. At this time, since the pressure difference ΔP23 between the fluid pressure P2 in the second back pressure chamber 214 and the fluid pressure P3 at the second main valve port 215 is large (ΔP23≥S1), as Figure 14 shown in the figure, the flow path switching spool 61 is pressed by the fluid flowing in the second pilot passage 225 to move to the downstream side (left side) and comes into contact with the valve seat portion 62. As a result, the fluid flowing in the second pilot passage 225 flows to the second main valve port 215 (the outlet flow path 110e) through the first communication hole 61c having a small flow path area. That is, the flow path switching mechanism 260 switches the second pilot passage 225 to the first passage mode F1.

[0125] When the fluid in the second back pressure chamber 214 flows to the first main valve port 215 through the first communication hole 61, the flow rate between the second back pressure chamber 214 and the second main valve port 215 becomes smaller than the flow rate between the second main valve chamber 213 and the second back pressure chamber 214. Therefore, the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P2 in the second back pressure chamber 214 are maintained at substantially the same value and gradually decrease. Then, when the fluid pressure P2 in the second back pressure chamber 214 decreases and the pressure difference ΔP23 becomes small (ΔP23<S1), the force by which the fluid flowing in the second pilot passage 225 presses the flow path switching spool 61 toward the downstream side becomes weak, as Figure 15 shown in the figure, the flow path switching spool 61 is pressed by the pressure difference operating spring 63 to move to the upstream side and is separated from the valve seat portion 62. As a result, the fluid flowing in the second pilot passage 225 flows to the second main valve port 215 through the second communication hole 62c having a large flow path area. That is, the flow path switching mechanism 260 switches the second pilot passage 225 to the second passage mode F2.

[0126] When the fluid in the second back pressure chamber 214 flows through the second flow hole 62c to the second main valve port 215, the flow rate between the second back pressure chamber 214 and the second main valve port 215 becomes greater than the flow rate between the second main valve chamber 213 and the second back pressure chamber 214. Therefore, the fluid pressure P2 in the second back pressure chamber 214 becomes less than the fluid pressure P1 in the second main valve chamber 213 (P1>P2), and the fluid pressure P2 in the second back pressure chamber 214 is almost the same as the fluid pressure P3 in the second main valve port 215 (P2≈P3). Consequently, the pressure difference ΔP12 between the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P2 in the second back pressure chamber 214 applies an upward pressing force to the second main valve core 220, such as... Figure 16 As shown, the second main valve core 220 separates from the second main valve seat 216, thereby opening the second main valve port 215. At this time, since the pressure difference ΔP13 between the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P3 in the second main valve port 215 is smaller than when the second pilot passage 225 was just opened, the rapid inflow of fluid from the second main valve chamber 213 into the second main valve port 215 can be suppressed. Thus, the first main valve port 115 is closed and the second main valve port 215 is open. In this state, the fluid enters from the intermediate flow path 110d, passes through the second main valve chamber 213 and the second main valve port 215, and flows out from the outlet flow path 110e.

[0127] Solenoid valve 3 has the same effect as solenoid valve 1 in the first embodiment described above.

[0128] (Fourth Embodiment)

[0129] The following is for reference Figures 17-21 The fourth embodiment of the electrically driven valve of the present invention, a pilot-operated solenoid valve, will be described.

[0130] Figure 17 This is a cross-sectional view of the electric valve according to the fourth embodiment of the present invention. Figures 18-21 It means Figure 17 A cross-sectional view of a portion of a solenoid valve. Figures 18-21 In the diagram, (a) is a sectional view of the main valve core and its interior, and (b) is an enlarged sectional view of the portion enclosed by the dashed line in (a). Figures 18-21 The sequence represents the states of the second main valve port being closed, intermediate state 1 (the second pressure equalization path is in the second path mode), intermediate state 2 (the second pressure equalization path is in the first path mode), and the second main valve port being open. Figure 18 , Figure 21 In the diagram, arrows schematically represent fluid flow. In the following description, components identical (including substantially identical) to the solenoid valve 3 of the third embodiment are marked with the same symbols and their descriptions are omitted.

[0131] like Figures 17-21As shown, the solenoid valve 4 of the fourth embodiment includes a valve body 110, a first main valve core 120, a drive unit 130, a first pilot valve core 140, a second main valve core 220, a second pilot valve core 240, and a flow path switching mechanism 270. The solenoid valve 4 has a flow path switching mechanism 270 with a different structure than the flow path switching mechanism 260 of the solenoid valve 3 described above.

[0132] The flow path switching mechanism 270 is disposed in the second pressure equalization passage 226. The flow path switching mechanism 270 has a flow path switching valve core 71, a valve seat portion 72, and a pressure differential working spring 73. Since these components have the same (including substantially the same) structure as the flow path switching valve core 71, valve seat portion 72, and pressure differential working spring 73 of the solenoid valve 2 described above, the same symbols are used and some descriptions are omitted.

[0133] The flow path area B2 of the second flow orifice 72c is larger than the flow path area B1 of the first flow orifice 71c. The flow path area Bp2 of the second pilot passage 225 is larger than the flow path area B1 of the first flow orifice 71c and smaller than the flow path area B2 of the second flow orifice 72c (B2>Bp2>B1). Furthermore, the flow path area is the cross-sectional area of ​​the narrowest part of the flow path. When the flow rate of the second pilot passage 225 (flow path area Bp2) is set to Qp2, the flow rate of the first flow orifice 71c (flow path area B1) is set to Q1, and the flow rate of the second flow orifice 72c (flow path area B2) is set to Q2, the solenoid valve 4 is configured such that the magnitudes of the flow rates are Q2>Qp2>Q1.

[0134] In the flow path switching mechanism 270, when the second pilot passage 225 is open, when the pressure difference ΔP12 between the fluid pressure P1 in the second main valve chamber 213 upstream of the second equalizing passage 226 and the fluid pressure P2 in the second back pressure chamber 214 downstream is small, or when the pressure difference ΔP12 is large and the pressure difference ΔP23 between the fluid pressure P2 in the second back pressure chamber 214 and the fluid pressure P3 in the second main valve port 215 is small, the force by which the fluid flowing in the second equalizing passage 226 presses the flow path switching valve core 71 downstream becomes greater than the force by which the pressure difference working spring 73 presses the flow path switching valve core 71 upstream. As a result, the flow path switching valve core 71 moves upstream and contacts the valve seat portion 72. Then, when the flow path switching valve core 71 contacts the valve seat portion 72, the switching valve portion 71a closes the second flow hole 72c, thereby allowing the fluid flowing in the second equalizing passage 226 to pass through the first flow hole 71c ( Figure 20The second pressure equalization passage 226E, which allows fluid to pass through the first flow hole 71c, is referred to as "first passage mode G1". The area of ​​the cross-sectional area of ​​the gap between the outer peripheral surface of the second flange 222 and the inner peripheral surface of the second space 110b, combined with the flow path area B1 of the first flow hole 71c, is the flow path area of ​​the pressure equalization passage 226E of the first passage mode G1. The flow path area of ​​the second pressure equalization passage 226E of the first passage mode G1 is smaller than the flow path area of ​​the second pilot passage 225.

[0135] In the flow path switching mechanism 270, when the second pilot passage 225 is open, and both the pressure difference ΔP12 and ΔP23 are large, the force by which the fluid flowing in the second equalizing passage 226 presses the flow path switching valve core 71 downstream is greater than the force by which the pressure difference working spring 73 presses the flow path switching valve core 71 upstream. As a result, the flow path switching valve core 71 moves downstream and separates from the valve seat portion 72. Then, when the flow path switching valve core 71 separates from the valve seat portion 72, the second flow hole 72c opens, and the fluid flowing in the second equalizing passage 226 passes through the second flow hole 72c (…). Figure 19 The second pressure equalization passage 226E, which allows fluid to pass through the second flow hole 72c, is referred to as "second passage mode G2". The area of ​​the gap between the outer peripheral surface of the second flange 222 and the inner peripheral surface of the second space 110b, combined with the flow path area B2 of the second flow hole 72c, is the flow path area of ​​the second pressure equalization passage 226E in the second passage mode G2. The flow path area of ​​the second pressure equalization passage 226E in the second passage mode G2 is larger than the flow path area of ​​the second pilot passage 225.

[0136] Next, refer to Figures 18-21 An example of the operation of solenoid valve 4 will be explained.

[0137] When coil 32 is energized, similar to solenoid valve 3 described above, solenoid valve 4 is in a state where the first main valve port 115 is open and the second main valve port 215 is closed. Figure 18 ).

[0138] Furthermore, when coil 32 is not energized, plunger 34 moves downward via plunger spring 35. Plunger 34 presses the first pilot valve core 140 against the first pilot valve seat 121b, thereby closing the first pilot passage 125. Moreover, the first pilot valve core 140 presses the first main valve core 120 (first main valve portion 121a) against the first main valve seat 116, thereby closing the first main valve port 115. Thus, the flow of fluid from the first main valve chamber 113 to the first main valve port 115 is cut off.

[0139] Additionally, the actuating rod 128 moves downward together with the first main valve core 120, and the actuating rod 128 presses the second pilot valve core 240 downward. Thus, as... Figure 19 As shown, the second pilot valve core 240 separates from the second pilot valve seat 228b, thereby opening the second pilot passage 225. When the second pilot passage 225 just opens, the pressure difference ΔP23 between the fluid pressure P2 in the second back pressure chamber 214 and the fluid pressure P3 in the second main valve port 215 is large, and fluid flows from the second back pressure chamber 214 to the second main valve port 215, thereby increasing the pressure difference ΔP12 between the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P2 in the second back pressure chamber 214. At this time, the flow rate of the fluid flowing in the second equalizing passage 226 is large, and the flow path switching valve core 71 is pressed upward by the fluid and separates from the valve seat portion 72. As a result, the fluid flowing in the second equalizing passage 226 flows to the second back pressure chamber 214 through the second flow hole 72c with a larger flow area. That is, the flow path switching mechanism 270 switches the second equalizing passage 226E to the second passage mode G2.

[0140] When the fluid in the second main valve chamber 213 flows through the second flow hole 72c to the second back pressure chamber 214, the flow rate between the second main valve chamber 213 and the second back pressure chamber 214 becomes greater than the flow rate between the second back pressure chamber 214 and the second main valve port 215. Therefore, the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P2 in the second back pressure chamber 214 gradually decrease and approach each other, thus reducing the pressure difference ΔP12. Furthermore, as the pressure difference ΔP12 decreases, the flow rate of the fluid flowing in the second equalizing passage 226 decreases, thereby weakening the force by which the fluid presses the flow path switching valve core 71 upwards. Figure 20 As shown, the flow path switching valve core 71 moves downward and contacts the valve seat portion 72. Consequently, the fluid flowing in the second pressure equalization passage 226 flows into the second back pressure chamber 214 through the first flow hole 71c, which has a smaller flow path area. That is, the flow path switching mechanism 270 switches the second pressure equalization passage 226E to the first passage mode G1.

[0141] When the fluid in the second main valve chamber 213 flows through the first flow hole 71c to the second back pressure chamber 214, the flow rate between the second main valve chamber 213 and the second back pressure chamber 214 becomes smaller than the flow rate between the second back pressure chamber 214 and the second main valve port 215. Therefore, compared to the fluid pressure P1 in the second main valve chamber 213, the fluid pressure P2 in the second back pressure chamber 214 decreases, the pressure difference ΔP12 increases (P1>P2) and the pressure difference ΔP23 decreases (P2≈P3), and the flow rate of the fluid flowing in the second pressure equalization passage 226 decreases, while the flow path switching valve core 71 remains in contact with the valve seat portion 72. Thus, the pressure difference ΔP12 between the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P2 in the second back pressure chamber 214 applies an upward pressing force to the second main valve core 220, such as... Figure 21 As shown, the second main valve core 220 separates from the second main valve seat 216, thereby opening the second main valve port 215. At this time, since the pressure difference ΔP13 between the fluid pressure P1 in the second main valve chamber 213 and the fluid pressure P3 in the second main valve port 215 is smaller than when the second pilot passage 225 is just opened, the rapid inflow of fluid from the second main valve chamber 213 into the second main valve port 215 can be suppressed. Thus, the first main valve port 115 is closed and the second main valve port 215 is open. In this state, fluid enters from the intermediate flow path 110d, passes through the second main valve chamber 213 and the second main valve port 215, and flows out from the outlet flow path 110e.

[0142] Solenoid valve 4 has the same effect as solenoid valve 2 in the second embodiment described above.

[0143] The embodiments of the present invention have been described above, but the present invention is not limited to these examples. Solutions obtained by adding, deleting, or modifying the constituent elements of the above embodiments, or by appropriately combining the features of the embodiments, as long as they do not violate the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. An electrically driven valve comprising: a valve body having a main valve chamber and a back pressure chamber; and a main valve core configured to divide the main valve chamber and the back pressure chamber, and to open and close a main valve port connected to the main valve chamber; A pressure equalization passage connects the main valve chamber and the back pressure chamber; A pilot passage that connects the back pressure chamber and the main valve port; a pilot valve core that opens and closes the pilot passage; And a drive unit that drives the pilot valve core, the electrically driven valve is characterized in that, It has a flow path switching mechanism that switches the pilot path to a first path mode with a flow path area smaller than the equalizing path mode and a second path mode with a flow path area larger than the equalizing path mode. The flow path switching mechanism is configured such that, when the pilot path is open, When the fluid pressure at the main valve port is lower than the fluid pressure in the back pressure chamber and the pressure difference between the fluid pressure in the back pressure chamber and the fluid pressure at the main valve port is large, the system switches to the first passage mode. When the pressure difference is small, switch to the second path mode.

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