Solenoid valve

Abstract

Improves the opening performance of normally open solenoid valves. [Solution] The sub-valve chamber 30 includes a back pressure chamber 34 and selectively communicates with the main valve chamber 13, a sub-valve port 32 that communicates the main valve chamber with the sub-valve chamber, a sub-valve element 29 that is provided so as to be movable relative to the main valve element 16 and moves forward and backward with respect to the sub-valve seat to open and close the sub-valve port, a first coil spring 36 that urges the main valve element in the valve opening direction via the sub-valve element and moves the main valve element and the sub-valve element in the valve opening direction when the drive device is not driven, and a sub-valve element 37 that is interposed between the main valve element and the sub-valve element and urges the main valve element in the valve closing direction to close the sub-valve. The valve is provided with a second coil spring 37 which biases the valve body in the valve opening direction, a sealing member 18 which can block the flow of fluid between the main valve chamber and the sub-valve chamber when the valve is closed and the main valve port 19 is closed by the main valve body and the sub-valve port is closed by the sub-valve body, and an introduction passage 17 which connects the sub-valve chamber to the outflow passage when the main valve port is closed by the main valve body. When driven, the drive device moves the sub-valve body in the valve closing direction, and moves the main valve body in the valve closing direction via the sub-valve body and the second coil spring.

Description

[Technical field]

[0001] The present invention relates to a solenoid valve, and more particularly to a solenoid valve equipped with an auxiliary valve that improves operability when the valve is opened. [Background technology]

[0002] 2. Description of the Related Art Solenoid valves that use an electromagnetic actuator to open and close a valve have conventionally been used in refrigeration cycle devices that have a refrigerant circuit, such as air conditioners, refrigeration devices, and freezing devices.

[0003] One such solenoid valve is a normally open type solenoid valve that uses the electromagnetic force of a solenoid to attract and hold the plunger in a closed state, while also opening the valve by having a coil spring (valve-opening spring) that urges the plunger and valve body in the opposite direction to the attraction direction (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-119298 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, due to the structure of the solenoid valve, the maximum differential pressure load (load due to the difference between the fluid pressure on the inflow side and the fluid pressure on the outflow side) is applied to the valve disc when the valve is closed with the valve disc seated on the valve seat. For this reason, it is not necessarily easy to ensure the reliability of the valve opening operation.

[0006] In particular, the larger the valve diameter is, and the higher the working pressure of the fluid is (i.e., when a high-pressure fluid is used), the larger the differential pressure load acting on the valve body becomes, making it more difficult for the valve to open.

[0007] On the other hand, it is possible to use a valve-opening spring with a large spring load (repulsive force) to ensure the valve is opened. However, increasing the spring load will require a larger valve-opening spring. Furthermore, the solenoid that closes the valve against the biasing force of the valve-opening spring will need to have a strong suction force, which will result in a larger drive unit.

[0008] On the other hand, it is also possible to utilize the invention described in Patent Document 1 to introduce the outlet pressure into the plunger chamber to cancel the pressure difference and improve the valve opening performance.

[0009] However, in the invention described in this document, the sealing member that prevents the high-pressure fluid on the inlet side from entering the plunger chamber generates sliding resistance in the valve body (valve holder), which in turn impedes the valve opening operation and reduces the effect of improving the valve opening performance.

[0010] Therefore, an object of the present invention is to provide a new normally open valve structure capable of improving the valve opening performance. [Means for solving the problem]

[0011] In order to solve the above problems and achieve the object, the present application presents two inventions. The first invention relates to a direct-acting solenoid valve, and the second invention relates to a pilot-operated solenoid valve. In this application, the term "the present invention" refers to both the first and second inventions. In this application, one side of the axial direction of the solenoid valve (which is also the direction of movement of the plunger, main valve body, auxiliary valve body, and pilot valve body) is defined as "upper" and the other side as "lower", and the description is given assuming that the drive unit is disposed above the valve body and the valve body is disposed below the drive unit, respectively. However, the solenoid valves of the present invention (the first and second inventions) can be used in various orientations (positions), and the "upper" and "lower" (the same applies to "upper surface", "lower surface", "upper side", "lower side", "upper", "lower", etc.) are convenient (relative) concepts for making the present invention easier to understand (the same applies to the embodiments described later). Furthermore, the terms "lifting," "ascending," and "descending" are sometimes used, with "lifting" meaning movement in a vertical direction, "ascending" meaning movement in an upward direction, and "descending" meaning movement in a downward direction.

[0012] [First Invention] The solenoid valve according to the first invention of the present application is a solenoid valve comprising: a flow path block having a main valve chamber communicating with an inlet path for introducing a fluid (e.g., a refrigerant / similar below) and an outlet path for discharging the fluid; a main valve port having a main valve seat and provided between the outlet path and the main valve chamber so as to open into the main valve chamber; a main valve body that opens and closes the main valve port by moving back and forth relative to the main valve seat; and a drive device including a plunger and a suction element that sucks the plunger.

[0013] The solenoid valve includes an auxiliary valve chamber including a back pressure chamber formed between the main valve body and the suction body and interposed between the main valve chamber and the suction body and selectively communicating with the main valve chamber; an auxiliary valve port having an auxiliary valve seat and communicating the main valve chamber with the auxiliary valve chamber; an auxiliary valve body provided movable relative to the main valve body in the axial direction of the solenoid valve and moving forward and backward with respect to the auxiliary valve seat to open and close the auxiliary valve port; and a drive device for biasing the main valve body in a valve opening direction via the auxiliary valve body to deactivate the drive device. The valve includes a first coil spring that moves the main valve element and the sub-valve element in a valve-opening direction when the drive device is actuated, a second coil spring that is interposed between the main valve element and the sub-valve element and that urges the main valve element in a valve-closing direction and the sub-valve element in a valve-opening direction, a seal member that can block the flow of fluid between the main valve chamber and the sub-valve chamber when the valve is closed and the main valve port is closed by the main valve element and the sub-valve port is closed by the sub-valve element, and an introduction passage that communicates the sub-valve chamber with the outflow passage when the main valve port is closed by the main valve element. The valve may be configured so that the drive device moves the sub-valve element in the valve-closing direction when actuated, and moves the main valve element in the valve-closing direction via the sub-valve element and the second coil spring.

[0014] In the present invention, a valve that includes a main valve element, a main valve seat, and a main valve port provided in a main valve chamber and that opens and closes a fluid flow path (main valve port) from an inflow passage to an outflow passage is referred to as a "main valve," and a valve that includes a sub-valve element, a sub-valve seat, and a sub-valve port provided in a sub-valve chamber and that opens and closes a sub-valve port that communicates between the main valve chamber and the sub-valve chamber is referred to as an "sub-valve." Furthermore, the above-mentioned "selectively communicates with the main valve chamber" regarding the sub-valve chamber means that the main valve chamber and the sub-valve chamber communicate with each other only when the sub-valve is open, and that the main valve chamber and the sub-valve chamber are not communicated with each other when the sub-valve is closed.

[0015] The solenoid valve according to the first invention of the present application is provided with an introduction passage for introducing low pressure in the outflow passage to a back pressure chamber formed on the back side of the main valve body, similar to the invention described in Patent Document 1, which is provided with an introduction passage for introducing low pressure in the outflow passage to a plunger chamber (back side of the main valve body). Therefore, the valve opening performance can be improved by canceling the differential pressure acting on the main valve body when the valve is closed (reducing the differential pressure load to zero).

[0016] To elaborate further on this point, the back pressure chamber is a space on the back side of the main valve body. Here, the main valve body moves forward and backward with respect to the main valve seat (moves toward the main valve seat and moves backward away from the main valve seat), and the "back side" of the main valve body refers to the surface opposite to the surface facing the main valve seat and the outflow passage (this surface is called the "front surface") in the axial direction (the direction in which the main valve body moves up and down). If the pressure in the back pressure chamber, which is the space on the back side, is greater than the pressure on the front surface (the surface facing the main valve seat), a force acts on the main valve body in the valve closing direction, making it difficult for the main valve body to open. Therefore, in the first invention, the low pressure in the outflow passage is introduced into the back pressure chamber through the introduction passage to balance the pressure on the front side and the pressure on the back side of the main valve body (eliminating the differential pressure load acting on the main valve body), making it easier to open the valve.

[0017] Furthermore, in the above solenoid valve, when the seal diameter when the main valve element sits on the main valve seat is called the "first seal diameter," the seal diameter when the sub-valve element sits on the sub-valve seat is called the "second seal diameter," and the seal diameter by the seal member is called the "third seal diameter," it is preferable that the first seal diameter, the second seal diameter, and the third seal diameter are made equal (identical). By making the seal diameters equal, the differential pressure load (axial direction, i.e., load in the direction of movement of the main valve element) acting on the main valve element in the closed state is eliminated (made zero), making it easier to open the valve.

[0018] The sealing member is typically provided between the main valve body and the sub-valve body, for example, between the outer circumferential surface of the main valve body and the inner circumferential surface of the sub-valve body, as in the embodiment described later, in order to reduce the sliding resistance caused by the sealing member.

[0019] Specifically, in the solenoid valve described in Patent Document 1, sliding resistance of the seal member occurs throughout the entire stroke of the lifting and lowering movement of the valve body. In contrast, in the first invention (similar to the second invention described later), the suction force of the attractor disappears when the power supply to the drive device (coil) is stopped, and the first coil spring and the second coil spring push up the main valve body and the sub-valve body in the valve opening direction to start the valve opening movement, but the main valve body and the sub-valve body move together without moving relative to each other in almost all the stroke from the closed state (the main valve and the sub-valve are completely closed) to the open state (the main valve and the sub-valve are fully open), and sliding resistance occurs only when there is a difference between the timing at which the main valve body leaves the main valve seat and the timing at which the sub-valve body leaves the sub-valve seat at the beginning of the valve opening movement (i.e., only during the very short time or stroke from the closed state until the main valve or the sub-valve opens slightly), when the main valve body and the sub-valve body move relative to each other. Therefore, according to the present invention, the sliding resistance caused by the seal member can be reduced compared to the conventional art. The valve closing operation is the reverse of the valve opening operation, but in this case too, the sliding resistance of the seal member is reduced, just as when the valve is opened. Furthermore, according to the first invention, it is possible to increase the valve diameter and reduce the size of the drive device. In addition, since the valve can be opened even when there is a high pressure difference between the inflow and outflow paths, it is easy to use high-pressure fluids.

[0020] [Second Invention] A pilot type solenoid valve according to a second aspect of the present invention comprises a flow path block having a main valve chamber and a pilot valve chamber therein, and having an inlet path for introducing fluid into the main valve chamber and an outlet path for discharging fluid from the main valve chamber, a main valve port having a main valve seat and provided between the outlet path and the main valve chamber so as to open to the main valve chamber, a main valve body that opens and closes the main valve port by moving toward and away from the main valve seat, a pilot passage that passes through the main valve body and selectively communicates the pilot valve chamber with the outflow path, a pilot valve port having a pilot valve seat and formed at an end of the pilot passage on the pilot valve chamber side, a pilot valve body that opens and closes the pilot valve port by moving toward and away from the pilot valve seat, a pressure equalizing passage that communicates the main valve chamber with the pilot valve chamber, and a drive device including a plunger and a suction element that sucks the plunger.

[0021] The pilot type solenoid valve further comprises: an auxiliary valve chamber including a back pressure chamber formed between the pilot valve body and the suction element and formed to be interposed between the pilot valve chamber and the suction element and selectively communicate with the pilot valve chamber; an auxiliary valve port having an auxiliary valve seat and communicating the pilot valve chamber with the auxiliary valve chamber; an auxiliary valve body provided movable relative to the pilot valve body in the axial direction of the solenoid valve and moving forward and backward with respect to the auxiliary valve seat to open and close the auxiliary valve port; and a sub-valve body that biases the pilot valve body in a valve opening direction via the sub-valve body and biases the pilot valve body in a valve opening direction when the drive device is not driven. and a first coil spring which moves the sub-valve element in a valve opening direction, a second coil spring which is interposed between the pilot valve element and the sub-valve element and which urges the pilot valve element in a valve closing direction and also urges the sub-valve element in a valve opening direction, a seal member which can block the flow of fluid between the pilot valve chamber and the sub-valve chamber when the pilot valve port is closed by the pilot valve element and the sub-valve port is closed by the sub-valve element, and an introduction passage which communicates the sub-valve chamber with the outflow passage via the pilot passage when the pilot valve port is closed by the pilot valve element. The actuator may be configured so that when actuated, the actuator moves the sub-valve element in the valve closing direction and also moves the pilot valve element in the valve closing direction via the sub-valve element and the second coil spring.

[0022] In the second invention, a valve that is provided in the pilot valve chamber, includes a pilot valve body, a pilot valve seat, and a pilot valve port, and opens and closes a pilot passage is called a "pilot valve." Furthermore, "selectively communicates the pilot valve chamber with the outflow passage" in the pilot passage means that the pilot valve chamber and the outflow passage are communicated only when the pilot valve is open, and that the pilot valve chamber and the outflow passage are not communicated when the pilot valve is closed. Furthermore, "selectively communicates with the pilot valve chamber" in the auxiliary valve chamber means that the pilot valve chamber and the auxiliary valve chamber are communicated only when the auxiliary valve is open, and that the pilot valve chamber and the auxiliary valve chamber are not communicated when the auxiliary valve is closed.

[0023] In the solenoid valve according to the second invention, the characteristic configuration (inlet passage and sub-valve) that functions to promote the opening operation of the main valve in the first invention is applied to the pilot valve. Therefore, according to the second invention, the opening performance of the main valve can be improved by improving the opening performance of the pilot valve. Furthermore, while the adoption of a pilot system generally allows the valve diameter to be made larger than that of a direct acting type, according to the second invention, it is possible to make the valve diameter even larger than that of a conventional pilot type solenoid valve.

[0024] Also, in the solenoid valve according to the second invention, when the seal diameter formed by the pilot valve body seating on the pilot valve seat is called the "first seal diameter," the seal diameter formed by the sub-valve body seating on the sub-valve seat is called the "second seal diameter," and the seal diameter formed by the seal member is called the "third seal diameter," it is preferable that the first seal diameter, the second seal diameter, and the third seal diameter are made the same. This is to eliminate the differential pressure load applied to the main valve body when the valve is closed, making it easier to open the valve, as in the first invention. Effect of the Invention

[0025] According to the present invention, the opening performance of the solenoid valve can be improved.

[0026] Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a solenoid valve according to a first embodiment of the present invention in an open state. [Diagram 2] FIG. 2 is an enlarged vertical cross-sectional view showing a main valve and an auxiliary valve portion (portion B in FIG. 1) when the solenoid valve according to the first embodiment is in an open state. [Diagram 3] FIG. 3 is a vertical cross-sectional view similar to FIG. 2, showing the solenoid valve according to the first embodiment in a state during a valve closing operation (a state in which the main valve is closed and the sub-valve is not yet closed). [Figure 4] FIG. 4 is an enlarged vertical cross-sectional view, similar to FIG. 2, showing the main valve and the sub-valve when the solenoid valve according to the first embodiment is in a closed state. [Diagram 5] FIG. 5 is a vertical sectional view showing a solenoid valve according to a second embodiment of the present invention in an open state. [Figure 6] FIG. 6 is an enlarged vertical cross-sectional view showing the pilot valve and the sub-valve portion (portion C in FIG. 5) when the solenoid valve according to the second embodiment is in an open state. [Figure 7] FIG. 7 is a vertical cross-sectional view similar to FIG. 6, showing the solenoid valve according to the second embodiment in a state during a valve closing operation (a state in which the pilot valve is closed and the sub-valve is not yet closed). [Figure 8] FIG. 8 is an enlarged longitudinal sectional view, similar to FIG. 6, showing the pilot valve and the sub-valve portion when the solenoid valve according to the second embodiment is in a closed state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] [First embodiment] A solenoid valve according to a first embodiment of the present invention will be described with reference to Figures 1 to 4. The first embodiment is an embodiment of the first invention.

[0029] As shown in Figures 1 to 4, the solenoid valve 11 of this embodiment is a direct-acting solenoid valve of a normally open type (always open type) that is in an open state when not energized, and has a main valve body 16 and a sub-valve body 29 arranged inside a flow path block 12 having a main valve chamber 13 and a sub-valve chamber 30, and an electromagnetic drive device (drive device) 38 for driving the main valve body 16 and the sub-valve body 29 is provided on the upper surface of the flow path block 12.

[0030] In the flow path block 12, a bottomed and uncovered vertical hole (the upper end is open and the lower end has a bottom) is formed that extends vertically (i.e., in the direction of the axis A of the solenoid valve 11) downward from the upper surface of the flow path block 12, and an auxiliary valve seat member (hereinafter simply referred to as "auxiliary valve seat") 31 is installed so as to separate the inside of this vertical hole into upper and lower spaces (an upper space and a lower space). The auxiliary valve seat 31 is a flat ring-shaped member with a central hole that becomes the auxiliary valve port 32, and is held horizontally (i.e., in a direction perpendicular to the axis A of the solenoid valve 11) by a suction member (described later) 25. The auxiliary valve seat 31 is structured so as to have a rubber coating on the upper surface of a metal plate to improve the refrigerant blocking performance (to prevent valve leakage).

[0031] The lower space of the vertical hole is the main valve chamber 13, and an inflow passage 14 for introducing the refrigerant into the main valve chamber 13 is opened on the side of the main valve chamber 13. An outflow passage 15 for discharging the refrigerant from the main valve chamber 13 is opened on the bottom of the main valve chamber 13. A main valve seat member (hereinafter simply referred to as "main valve seat") 20 with which the main valve body 16 comes into contact (abuts and separates) is installed in a main valve port 19, which is the opening of the outflow passage 15 to the main valve chamber 13. The main valve seat 20 is a flat ring-shaped member having a central hole, similar to the sub-valve seat 31. The main valve seat 20 is structured with rubber coatings on both sides (upper and lower) of the metal plate to improve the refrigerant blocking performance (to prevent valve leakage).

[0032] The upper space of the vertical hole serves as a connection opening 21 for fixing the suction member 25, and also serves as an auxiliary valve chamber 30 including a back pressure chamber 34.

[0033] Specifically, the suction member 25 has a disk-shaped flange portion 25b that extends so as to be placed on the upper surface of the flow path block 12, a cylindrical suction body 25a that rises upward from the center of the flange portion 25b, and a cylindrical guide portion 25c that falls downward from the lower surface of the flange portion 25b.

[0034] The guide portion 25c accommodates the sub-valve body 29 therein and holds it slidably in the vertical direction (i.e., in the direction of the axis A of the solenoid valve 11). A male thread is formed on the outer peripheral surface of the guide portion 25c, and the suction member 25 is fixed to the flow path block 12 by screwing the guide portion 25c into the connection opening 21 while screwing the male thread into a female thread formed on the inner peripheral surface of the connection opening 21 (upper part of the vertical hole). At this time, the flange portion 25b abuts against the upper surface of the flow path block 12, but a seal member 22 is interposed between the lower surface of the flange portion 25b and the upper surface of the flow path block 12 to prevent the refrigerant from leaking out of the main valve chamber 13 to the outside.

[0035] The aspirator body 25a has a cylindrical shape with a central hole 25d penetrating in the vertical direction. A sleeve 23 is fixed to the outer peripheral surface of the upper end of the aspirator body 25a so as to rise upward from the upper end of the aspirator body 25a. The sleeve 23 is a cylindrical member, and houses the plunger 24 inside so as to be slidable in the vertical direction. The plunger 24 has a disk-shaped bottom 24a and a ring-shaped peripheral wall 24b rising upward from the outer peripheral part of the bottom 24a. A guide member 26 is inserted into the peripheral wall 24b from the upper side, and the plunger 24 slides smoothly in the vertical direction without tilting, guided by the guide member 26 and the inner peripheral surface of the sleeve 23. The upper surface of the sleeve 23 is closed by the guide member 26, and the lower surface of the sleeve 23 is closed by the aspirator body 25a.

[0036] The attractor body 25a attracts the plunger 24 by a magnetic force generated by a coil 39 included in the driving device 38, and is provided with a shaft 27 that is inserted into the central hole 25d from the upper side of the attractor body 25a. The shaft 27 is a rod-shaped member, and the upper end is connected (fixed) to the bottom 24a of the plunger 24. On the other hand, a connecting member 28 is provided on the lower surface side of the attractor body 25a so that a force in the vertical direction can be transmitted between the plunger 24 and the sub-valve body 29 via the shaft 27. The connecting member 28 has a disk-shaped base 28a that is connected to the sub-valve body 29, and a rod-shaped rod portion 28b that rises upward from the center of the base 28a. The upper end of the rod portion 28b is inserted into the central hole 25d of the attractor body 25a from below, and abuts against the shaft 27 inside the central hole 25a.

[0037] The sub-valve body 29 housed within the guide portion 25c has an overall cylindrical shape and has openings on the upper and lower surfaces. The base 28a of the connection member 28 is connected and fixed to the opening on the upper surface. The opening on the lower surface is formed with a ring-shaped bottom plate portion that protrudes horizontally inward from the lower end of the side wall 29a of the sub-valve body 29 toward the center (axis A) of the sub-valve body 29. In addition, a ring-shaped protrusion portion 29c that protrudes vertically downward is formed on the lower surface of the bottom plate portion, and this protrusion portion 29c abuts against the sub-valve seat 31 to close the sub-valve port 32.

[0038] The main valve element 16 has a main valve body 16a that opens and closes a main valve port 19 by moving toward and away from a main valve seat 20, a valve stem portion 16b that supports the main valve body 16a, and a head portion 16c formed at the upper end of the valve stem portion 16b so as to have a larger diameter than the valve stem portion 16b. The main valve body 16a is fixed to the lower end of the valve stem portion 16b. The main valve element 16 also has an introduction passage 17 that vertically passes through the main valve body 16a, the valve stem portion 16b, and the head portion 16c to communicate between the upper side of the main valve element 16 and the lower side of the main valve element 16 (i.e., to communicate between the outflow passage 15 and the sub-valve chamber 30 when the main valve port 19 is closed by the main valve element 16).

[0039] The main valve body 16 is connected to the sub-valve body 29 so as to be movable relative to each other in the vertical direction. Specifically, the head portion 16c of the main valve body 16 is accommodated in the lower part of the internal space of the sub-valve body 29, the valve shaft portion 16b of the main valve body 16 penetrates the bottom plate portion 29b of the sub-valve body 29, and the main valve body 16a is arranged below (below) the sub-valve seat 31. The head portion 16c of the main valve body 16 is slidable in the vertical direction along the inner peripheral surface of the side wall 29a of the sub-valve body 29. In other words, the guide portion 25c of the suction member 25, the sub-valve body 29, and the main valve body 16 (head portion 16c) are provided in a nested manner, and each member (the guide portion 25c and the sub-valve body 29, and the sub-valve body 29 and the main valve body 16) is slidable relative to each other in the vertical direction.

[0040] A step is formed on the outer peripheral surface of the upper part of the sub-valve element 29, and a compression coil spring (a spring installed in a compressed state) 36 is provided between this step and the sub-valve seat 31. This compression coil spring 36 corresponds to the "first coil spring" of the present invention (also referred to as the "first coil spring" in this embodiment), and urges the main valve element 16 upward (i.e., in the valve opening direction) via the sub-valve element 29, thereby performing the function of moving the main valve element 16 and the sub-valve element 29 upward when the drive device 38 is not driven.

[0041] Furthermore, a compression coil spring 37 is provided between the main valve element 16 (upper surface of the main valve body 16a) and the sub-valve element 29 (lower surface of the bottom plate portion 29b). This compression coil spring 37 corresponds to the "second coil spring" of the present invention (also referred to as the "second coil spring" in this embodiment), and serves to urge the main valve element 16 downward and the sub-valve element 29 upward, returning the main valve element 16 to a fixed position (the position where the main valve element 16 is most depressed relative to the sub-valve element 29) when the valve is opened. The second coil spring 37 is disposed so as to penetrate the central hole (sub-valve port) 32 of the sub-valve seat 31 along the outer circumferential surface of the valve stem portion 16b.

[0042] The internal space of the guide portion 25c of the suction member 25 on which the sub-valve element 29 is provided becomes the sub-valve chamber 30, and within this sub-valve chamber 30, the space above the main valve element 16, more precisely the space surrounded by the head portion 16c of the main valve element 16, the base portion 28a of the connecting member 28, and the side wall 29a of the sub-valve element 29 becomes the back pressure chamber 34. The space around the sub-valve element 29, more precisely the space 33 surrounded by the sub-valve element 29, the guide portion 25c of the suction member 25, and the sub-valve sheet 31, is referred to as the "sub-valve outer chamber." Also, a communication hole 35 that connects the sub-valve outer chamber 33 and the back pressure chamber 34 is formed in the side wall 29a of the sub-valve element 29.

[0043] Furthermore, a seal member (e.g., an O-ring) 18 is provided on the outer periphery of the head portion 16c of the main valve element 16 so as to be interposed between the head portion 16c and the inner periphery of the side wall 29a of the sub-valve element 29. This seal member 18 functions to block the flow of refrigerant between the inlet passage 14 and the back pressure chamber 34 (sub-valve chamber 30) when the main valve element 16 is seated on the main valve seat 20 and the sub-valve element 29 is seated on the sub-valve seat 31, thereby closing the valve.

[0044] In this embodiment, the seal diameter (first seal diameter) D1 formed when the main valve element 16 is seated on the main valve seat 20, the seal diameter (second seal diameter) D2 formed when the sub-valve element 29 is seated on the sub-valve seat 31, and the seal diameter (third seal diameter) D3 formed by the seal member 18 provided around the head portion 16c of the main valve element 16 are all set to be the same (see FIG. 4). This is to make it easier to open the valve by eliminating (making zero) the differential pressure load (load in the axial direction, i.e., the operating direction of the main valve element 16) acting on the main valve element 16 in the closed valve state.

[0045] In addition, in this embodiment, the plunger 24, shaft 27, suction member 25 (suction member main body 25a, flange portion 25b and guide portion 25c), sub-valve body 29 (ring-shaped protrusion portion 29c), main valve body 16 (main valve body 16a, valve stem portion 16b and head portion 16c), main valve port 19, main valve seat 20, sub-valve port 32 and sub-valve seat 31 are arranged coaxially, and their central axes A coincide with the axis A of the solenoid valve 11.

[0046] The operation of the solenoid valve 11 of this embodiment will be described as follows.

[0047] 1 and 2, the sub-valve body 29 is pushed upward by the biasing force of the first coil spring 36 to open the sub-valve, and the plunger 24 is also pushed upward via the connecting member 28 connected to the sub-valve body 29. The head portion 16c is lifted upward by the bottom plate portion 29b of the sub-valve body 29, causing the main valve body 16 to move upward and opening the main valve. In this open state, the sub-valve body 29 is pressed against the ceiling surface of the internal space of the attraction member 25 (guide portion 25c) by the upward biasing force of the first coil spring 36, thereby maintaining the open state.

[0048] Therefore, in the above-mentioned open valve state, the refrigerant that has flowed into the main valve chamber 13 through the inflow passage 14 flows out through the main valve port 19 and outflow passage 15 to the outside (see arrow F in FIG. 1). Note that refrigerant also flows from the main valve chamber 13 into the sub-valve chamber 30 (sub-valve outer chamber 33) through the sub-valve port 32, but this refrigerant enters the back pressure chamber 34 through the communication hole 35 formed in the side wall 29a of the sub-valve body 29 from the sub-valve outer chamber 33, and then passes through the introduction passage 17 of the main valve body 16 and the main valve chamber 13 (the space directly above the main valve port 19) in this order, before being discharged from the outflow passage 15 to the outside.

[0049] When the coil 39 is energized in the above-mentioned valve open state, the plunger 24, the connecting member 28, and the sub-valve element 29 are pulled toward the attractor body 25a, and are pushed downward together against the biasing force of the first coil spring 36. At this time, the main valve body 16a receives a downward (valve closing) force from the sub-valve element 29 via the second coil spring 37, and the main valve element 16 moves downward together with the sub-valve element 29 (as a unit). Then, the main valve element 16 moving downward seats on the main valve seat 20 as shown in FIG. 3, and the main valve port 19 is closed. In this state, the sub-valve element 29 is not yet seated on the sub-valve seat 31, and the sub-valve port 32 is open. Therefore, the refrigerant that flows into the sub-valve chamber 30 (sub-valve outer chamber 33) through the sub-valve port 32 passes through the sub-valve outer chamber 33, the communication hole 35 formed in the side wall 29a of the sub-valve body 29, the back pressure chamber 34, the inlet passage 17 of the main valve body 16, and the main valve chamber 13 (the space directly above the main valve port 19), in the same manner as described above, and is discharged to the outside through the outlet passage 15.

[0050] As the sub-valve element 29 continues to move downward, it seats on the sub-valve seat 31 as shown in FIG. 4, closing the sub-valve, and the main valve and the sub-valve are both closed to form a completely closed valve state. In this closed valve state, it is preferable to form a small gap (air gap) between the suction body 25 and the plunger 24. This is to ensure that the valve elements (main valve element 16 and sub-valve element 29) are seated (contacted) on the respective seats (main valve seat 20 and sub-valve seat 31) when the valve is closed, preventing valve leakage. It is preferable to set the air gap as small as possible in order to increase the force that maintains the closed valve state (the force that presses the valve elements 16, 29 against the respective seats 20, 31).

[0051] In the above-mentioned valve closed state, all flow paths from the inflow path 14 to the outflow path 15 are blocked, including the flow path via the sub-valve chamber 30 (sub-valve outer chamber 33) and the back pressure chamber 34. In addition, in this valve closed state, the low pressure in the outflow path 15 is introduced into the back pressure chamber 34 through the introduction path 17, and the three seal diameters D1, D2, D3 are set to be the same, so that the differential pressure load acting on the upper and lower surfaces of the main valve element 16 is canceled (reduced to zero).

[0052] When power supply to the coil 39 is stopped in the above-mentioned closed valve state, the attractive force with which the attractor body 25a attracts the plunger 24 disappears. As a result, the sub-valve body 29 is lifted by the biasing force of the first coil spring 36, and the head portion 16c of the main valve body 16 is pulled up by the bottom plate portion 29b, causing the main valve body 16 to move upward. At this time, since the differential pressure load acting on the upper and lower surfaces of the main valve body 16 is canceled as described above, the main valve body 16 can be more reliably raised and opened.

[0053] Second Embodiment A solenoid valve 41 according to a second embodiment of the present invention will be described with reference to Figures 5 to 8. The second embodiment is an embodiment of the second invention.

[0054] The solenoid valve 41 according to the second embodiment of the present invention is a normally open type solenoid valve that is in an open state when not energized, and is a pilot type solenoid valve that controls the main valve by a pilot valve. In addition, while an auxiliary valve is provided for the main valve in the first embodiment, a similar auxiliary valve is provided for the pilot valve in this embodiment. In the following description, the same reference numerals are used for configurations similar to those in the first embodiment, and duplicated descriptions are omitted, and the description will focus on the differences.

[0055] As shown in FIGS. 5 to 8, the solenoid valve 41 according to this embodiment includes a flow path block 12 having a main valve chamber 13 and a pilot valve chamber 48 therein, and having an inflow path 14 for introducing a fluid into the main valve chamber 13 and an outflow path 15 for discharging the fluid from the main valve chamber 13, a main valve port 19 having a main valve seat 42 and provided at the end of the outflow path 15 on the main valve chamber 13 side so as to open into the main valve chamber 13, a main valve element 16 which moves forward and backward relative to the main valve seat 42 to open and close the main valve port 19, and a valve element 16 which passes through the main valve element 16 and selectively connects the pilot valve chamber 48 and the outflow path 15. the pilot passage 45 for opening and closing the pilot passage 45; a pilot valve seat member (hereinafter simply referred to as "pilot valve seat") 49 installed at the end of the pilot passage 45 on the pilot valve chamber 48 side; a pilot valve body 47 for opening and closing the pilot passage 45 by moving toward and away from the pilot valve seat 49; a pressure equalizing path 46 for communicating between the main valve chamber 13 and the pilot valve chamber 48; and an electromagnetic drive device (drive device) 38 for driving the pilot valve body 47, the pressure equalizing path 46 including the plunger 24 and an attractor (attractor body 25a) for attracting the plunger 24.

[0056] The main valve element 16 is supported by a main valve guide member 43 installed in the upper opening of the flow path block 12 so as to be slidable in the vertical direction. That is, the main valve guide member 43 has a central hole penetrating in the vertical direction, and the upper part of the main valve element 16 is inserted into the lower part of the central hole so as to be slidable in the vertical direction. The main valve chamber 13 is also provided with a main valve opening spring 44 that opens the main valve when the drive unit 38 is not driven. The main valve opening spring 44 is a compression coil spring (a coil spring installed in a compressed state), and urges the main valve element 16 upward (in the valve opening direction). The above configurations are similar to those of a conventional pilot type solenoid valve.

[0057] Meanwhile, unlike conventional pilot type solenoid valves, the solenoid valve of this embodiment is provided with an auxiliary valve in the pilot valve. The configuration related to this auxiliary valve is similar to each configuration provided in the main valve of the first embodiment, and the solenoid valve 41 of this embodiment also includes an auxiliary valve body 29, an auxiliary valve seat 31, a first coil spring 36, a second coil spring 37, a seal member 18, an attractor member 25, a sleeve 23, a guide member 26, a shaft 27, a connecting member 28, an auxiliary valve chamber 30 including an auxiliary valve outer chamber 33 and a back pressure chamber 34, a communication hole 35, an introduction passage 17, etc.

[0058] In the first embodiment, the suction member 25 is fixed to the flow path block 12, but in this embodiment, since the pilot valve is provided with an auxiliary valve, the suction member 25 is fixed to the main valve guide member 43 (to the upper part of the central hole) fixed to the flow path block 12.

[0059] In this embodiment, since the pilot valve is provided with an auxiliary valve, the introduction passage 17 that introduces the low pressure in the outflow passage 15 to the back pressure chamber 34 when the valve is closed is formed in the pilot valve body 47. Unlike the first embodiment in which the introduction passage 17 directly communicates with the outflow passage 15 when the valve is closed, in this embodiment, the introduction passage 17 communicates with the outflow passage 15 via a pilot passage 45 when the valve is closed.

[0060] Also, unlike the first embodiment, in this embodiment, the second coil spring 37 is installed on the upper surface of the pilot valve body 47, i.e., inside the back pressure chamber 34. This second coil spring 37 urges the pilot valve body 47 downward and also urges the sub-valve body 29 upward via the connecting member 28, thereby returning the pilot valve body 47 to its home position (the position where the pilot valve body 47 is most depressed in terms of its relative positional relationship with the sub-valve body 29) when the valve is opened.

[0061] In this embodiment, the connecting member 28 has a hat-like shape to accommodate the second coil spring 37. The function of the connecting member 28 (the function of transmitting the downward force from the shaft 27 to the sub-valve body 29 and the function of transmitting the upward force from the sub-valve body 29 to the shaft 27) is the same as that of the connecting member 28 in the first embodiment.

[0062] Furthermore, also in this embodiment, the seal diameter (first seal diameter) D1 formed when the pilot valve element 47 seats on the pilot valve seat 49, the seal diameter (second seal diameter) D2 formed when the sub-valve element 29 seats on the sub-valve seat 31, and the seal diameter (third seal diameter) D3 formed by the seal member 18 around the pilot valve element 47 are made to be the same (see FIG. 8). This is to make it easier to open the pilot valve by eliminating (making zero) the differential pressure load (the load in the axial direction, i.e., the operating direction of the pilot valve element 47) acting on the pilot valve element 47 in the closed valve state.

[0063] The operation of the solenoid valve of this embodiment will be described as follows.

[0064] 5 and 6, the sub-valve body 29 is pushed upward by the biasing force of the first coil spring 36 to open the sub-valve, and the plunger 24 is also pushed upward via the connecting member 28 connected to the sub-valve body 29. The pilot valve body 47 is also lifted upward by the bottom plate portion 29b of the sub-valve body 29, and the pilot valve is also open. In this open state, the sub-valve body 29 is pressed against the ceiling surface of the internal space of the attraction member 25 (guide portion 25c) by the upward biasing force of the first coil spring 36, thereby maintaining the open state.

[0065] In the above-mentioned open valve state, the pilot passage 45 is open, and the refrigerant that flows from the inflow passage 14 into the main valve chamber 13 and passes through the pressure equalizing passage 46 into the pilot valve chamber 48 does not accumulate in the pilot valve chamber 48, but is discharged from the outflow passage 15 through the pilot passage 45. As a result, the pressure in the pilot valve chamber 48 does not increase, and the main valve element 16 is pressed against the inner ceiling surface of the main valve guide member 43 by the urging force of the main valve opening spring 44 that urges the main valve element 16 upward (in the valve opening direction), maintaining the open valve state, and the refrigerant that has flowed from the inflow passage 14 into the main valve chamber 13 (see arrow F) flows out from the outflow passage 15 (see arrow F).

[0066] When current is applied to the coil 39 from the above-mentioned valve open state, the plunger 24, the connecting member 28, and the sub-valve body 29 are pulled toward the attractor body 25a, and are pushed downward together with the plunger 24, the connecting member 28, and the sub-valve body 29 against the biasing force of the first coil spring 36. At this time, the pilot valve body 47 receives a downward (valve closing direction) force from the connecting member 28 via the second coil spring 37, and the pilot valve body 47 moves downward together with the sub-valve body 29 (as a unit). Then, the pilot valve body 47 moving downward is seated on the pilot valve seat 49 as shown in FIG. 7, and the pilot passage 45 is closed.

[0067] As the sub-valve element 29 continues to move downward, it seats on the sub-valve seat 31 as shown in Fig. 8, closing the sub-valve and bringing both the pilot valve and the sub-valve into a closed state. As in the first embodiment, it is preferable to leave a small gap (air gap) between the suction element main body 25 and the plunger 24 in this state. This is to ensure that each valve element (pilot valve element 47 and sub-valve element 29) is in contact with each seat (pilot valve seat 49 and sub-valve seat 31) when the valve is closed, thereby preventing valve leakage.

[0068] When the pilot passage 45 is closed as described above, the refrigerant flowing into the pilot valve chamber 48 through the pressure equalizing passage 46 accumulates without being discharged through the pilot passage 45, and the pressure in the pilot valve chamber 48 rises. Then, when the force pressing the main valve element 16 downward, which is caused by the refrigerant pressure in the pilot valve chamber 48 (more precisely, the pressure difference between the pilot valve chamber 48 and the main valve chamber 13) and the suction force of the suction element body 25a (the downward force that attracts the plunger 24), exceeds the upward biasing force of the main valve-opening spring 44, the main valve element 16 descends and seats on the main valve seat 42. This closes the main valve port 19, resulting in a completely closed valve state.

[0069] In the above-mentioned fully closed valve state, the low pressure in the outflow passage 15 is introduced into the back pressure chamber 34 through the pilot passage 45 and the inlet passage 17, and since the three seal diameters D1, D2, D3 are set to be the same, the differential pressure load acting on the upper and lower surfaces of the pilot valve body 47 is canceled (reduced to zero).

[0070] When power supply to the coil 39 is stopped from the above-mentioned fully closed valve state, the attractive force with which the attractor body 25a attracts the plunger 24 disappears. As a result, the sub-valve body 29 is lifted by the biasing force of the first coil spring 36, and the pilot valve body 47 is pulled up by the bottom plate portion 29b. At this time, since the differential pressure load acting on the upper and lower surfaces of the pilot valve body 47 is canceled as described above, the pilot valve body 47 can be more reliably raised and opened. Therefore, according to this embodiment, the opening performance of the main valve can be improved by improving the opening performance of the pilot valve.

[0071] When the pilot valve opens, the refrigerant accumulated in the pilot valve chamber 48 is discharged to the outflow passage 15 through the pilot passage 45, and the pressure in the pilot valve chamber 48 drops. Furthermore, the cross-sectional area of ​​the pilot passage 45 is larger than that of the pressure equalizing passage 46, so that a pressure difference that pulls the main valve element 16 upward occurs between the upper and lower surfaces of the main valve element 16. In addition, the main valve opening spring 44 has a biasing force that pulls the main valve element 16 upward. As a result, the main valve element 16 is pushed up and separates from the main valve seat 42, resulting in an open state in which the main valve port 19 is open (see Figures 5 and 6). [Explanation of symbols]

[0072] A axis (center axis) F Refrigerant flow D1 First seal diameter D2 Second seal diameter D3 3rd seal diameter 11 Direct acting solenoid valve 12 Flow path block 13 Main valve chamber 14 Inflow channel 15 Outflow channel 16 Main valve body 16a Main valve body 16b Valve stem 16c Head 17 Introductory path 18 Sealing material (O-ring) 19 Main valve port 20 Main valve seat member 21 Connection opening 22 Sealing material 23 Sleeve 24 Plunger 24a Bottom of plunger 24b Plunger peripheral wall 25 Suction element 25a Attractor body 25b Flange part 25c Guide part 25d Center hole of the aspirator body 26 Guide member 27 Shaft 28 Connection parts 28a Base of connecting member 28b Rod portion of connecting member 29 Sub valve body 29a Side wall of the sub-valve body 29b Bottom plate of sub-valve body 29c protrusion 30 Sub-valve chamber 31 Sub-valve seat member 32 Sub-mouth 33 Subventricular chamber 34 Back pressure chamber 35 Communication hole 36 First coil spring 37 Second coil spring 38 Electromagnetic drive unit (drive unit) 39 Coil 41 Pilot operated solenoid valve 42 Main valve seat 43 Main valve guide member 44 Main valve opening spring 45 Pilot Passage 46 Pressure Equalizing Path 47 Pilot valve body 48 Pilot valve chest 49 Pilot valve seat member

Claims

1. a flow path block having a main valve chamber communicating with an inflow path through which a fluid flows and an outflow path through which the fluid flows out; a main valve port having a main valve seat and disposed between the outlet passage and the main valve chamber so as to open into the main valve chamber; a main valve body that moves forward and backward relative to the main valve seat to open and close the main valve port; A drive device including a plunger and an attractor that attracts the plunger; A solenoid valve comprising: a sub-valve chamber including a back pressure chamber formed between the main valve body and the suction element, the sub-valve chamber being interposed between the main valve chamber and the suction element and selectively communicating with the main valve chamber; an auxiliary valve port having an auxiliary valve seat and communicating the main valve chamber with the auxiliary valve chamber; a sub-valve body that is movable relative to the main valve body in the axial direction of the solenoid valve and moves toward and away from the sub-valve seat to open and close the sub-valve port; a first coil spring that biases the main valve body in a valve opening direction via the sub-valve body and moves the main valve body and the sub-valve body in the valve opening direction when the drive device is not driven; a second coil spring interposed between the main valve body and the sub-valve body to bias the main valve body in a valve closing direction and bias the sub-valve body in a valve opening direction; a seal member capable of blocking the flow of the fluid between the main valve chamber and the sub-valve chamber when the main valve port is closed by the main valve element and the sub-valve port is closed by the sub-valve element; an introduction passage that communicates the sub-valve chamber with the outflow passage when the main valve port is closed by the main valve body; A solenoid valve comprising:

2. When driven, the drive device moves the sub-valve element in a valve closing direction and also moves the main valve element in the valve closing direction via the sub-valve element and the second coil spring. The solenoid valve according to claim 1 .

3. a seal diameter formed when the main valve body is seated on the main valve seat is defined as a first seal diameter; a seal diameter formed when the sub-valve body is seated on the sub-valve seat is a second seal diameter; The seal diameter by the seal member is a third seal diameter. When referring to each of them, The first seal diameter, the second seal diameter, and the third seal diameter are made equal to each other.

3. The solenoid valve according to claim 1 or 2.

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