Electromagnetic valve

Abstract

To improve the valve opening performance of a normally open solenoid valve.SOLUTION: A sub-valve chamber 30 including the back pressure chamber 34 and selectively communicating with the main valve chamber 13, a sub-valve port 32 communicating the main valve chamber and the sub-valve chamber, a sub-valve body 29 provided to be relatively movable with respect to the main valve body 16 and moving forward and backward with respect to the sub-valve seat to open and close the sub-valve port, and a first coil spring 36 biasing the main valve body in a valve opening direction via the sub-valve body and moving the main valve body and the sub-valve body in the valve opening direction when the driving device is not driven; A second coil spring 37 interposed between the main valve element and the sub-valve element and configured to urge the main valve element in a valve closing direction and urge the sub-valve element in a valve opening direction, a seal member 18 configured to block a flow of a fluid between the main valve chamber and the sub-valve chamber during valve closing in which the main valve port 19 is closed by the main valve element and the sub-valve port is closed by the sub-valve element, and an introduction path 17 configured to cause the sub-valve chamber and the outflow path to communicate with each other when the main valve port is closed by the main valve element, the main valve body is moved in the valve closing direction via the sub valve body and the second coil spring.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solenoid valve, and more particularly to a solenoid valve provided 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, refrigerators, and refrigeration devices.

[0003] Furthermore, one such solenoid valve is a normally open type (always open) solenoid valve that attracts and holds the plunger in a closed state using the electromagnetic force of a solenoid, while opening the valve by providing a coil spring (valve-opening spring) that urges the plunger and valve body in the opposite direction to the attracting direction (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-119298 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 (the load caused by the difference in fluid pressure between the inlet and outlet passages) is applied to the valve disc when the valve is closed with the disc seated on the valve seat. For this reason, it is not necessarily easy to ensure reliable valve opening.

[0006] In particular, the larger the valve diameter and the higher the operating pressure of the fluid (that is, when a high-pressure fluid is used), the greater the differential pressure load acting on the valve element, making it more difficult to open the valve.

[0007] On the other hand, to ensure the valve opens reliably, it is possible to use a valve-opening spring with a large spring load (repulsive force). However, increasing the spring load requires a larger valve-opening spring. Furthermore, the solenoid that closes the valve against the biasing force of the valve-opening spring also requires a strong suction force, which results in an increased size of the drive unit.

[0008] On the other hand, it is also conceivable to utilize the invention described in Patent Document 1 to cancel the differential pressure by introducing the outlet pressure into the plunger chamber, thereby improving the valve opening performance.

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

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

[0011] To solve the above problems and achieve the objectives, this 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. Note that the term "the present invention" in this application refers to both the first and second inventions. Furthermore, 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 element, sub-valve element, and pilot valve element) is referred to as "upper" and the other side as "lower," and the description will be given assuming that the drive unit is located above the valve body and the valve body is located below the drive unit. However, the solenoid valves of the present invention (the first and second inventions) can be used in various orientations (postures), and the terms "upper" and "lower" (the same applies to "upper surface," "lower surface," "upper side," "lower side," "upper," "lower," etc.) are merely expedient (relative) concepts to facilitate understanding of the present invention (the same applies to the embodiments described below). Also, the terms "lifting," "ascent," and "descent" are sometimes used, with "lifting" meaning movement in the up and down direction, "ascent" meaning movement in the upward direction, and "descent" meaning movement in the 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; the same applies hereinafter) 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 moves back and forth relative to the main valve seat to open and close the main valve port; and a drive device including a plunger and an attractor that attracts the plunger.

[0013] The solenoid valve includes a sub-valve chamber which includes a back pressure chamber formed between the main valve element and the attractor and is formed so as to be interposed between the main valve chamber and the attractor and which selectively communicates with the main valve chamber; a sub-valve port which has a sub-valve seat and which communicates the main valve chamber with the sub-valve chamber; a sub-valve element which is provided so as to be movable relative to the main valve element in the axial direction of the solenoid valve and which moves forward and backward with respect to the sub-valve seat to open and close the sub-valve port; and a drive device which biases the main valve element in the valve opening direction via the sub-valve element to deactivate the drive device. The valve comprises 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 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 connects the sub-valve chamber to the outflow passage when the main valve port is closed by the main valve element. The valve may also be configured so that when actuated, the drive device moves the sub-valve element in the valve-closing direction 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 provided in a main valve chamber, which includes a main valve element, a main valve seat, and a main valve port, and which opens and closes a fluid flow path (main valve port) from an inlet passage to an outlet passage, is referred to as a "main valve," and a valve provided in a sub-valve chamber, which includes a sub-valve element, a sub-valve seat, and a sub-valve port, and which opens and closes a sub-valve port that communicates the main valve chamber with the sub-valve chamber, is referred to as a "sub-valve." Furthermore, the phrase "selectively communicates with the main valve chamber" in relation to the sub-valve chamber means that the main valve chamber and the sub-valve chamber communicate 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 that introduces low pressure in the outflow passage into 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 that introduces low pressure in the outflow passage into the plunger chamber (back side of the main valve body). Therefore, by canceling the differential pressure acting on the main valve body when the valve is closed (making the differential pressure load zero), it is possible to improve the valve opening performance.

[0016] To elaborate further on this point, the back pressure chamber is a space on the back side of the main valve element. Here, the main valve element moves toward and away from the main valve seat relative to the main valve seat (moving toward and away from the main valve seat). The "back side" of the main valve element refers to the surface opposite the surface facing the main valve seat and the outflow passage (referred to as the "front side") in the axial direction (the direction in which the main valve element 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 side (the surface facing the main valve seat), a force acts on the main valve element in the valve closing direction, making it difficult for the main valve element to open. Therefore, in the first aspect of the present invention, the low pressure in the outflow passage is introduced into the back pressure chamber through the introduction passage, thereby balancing the pressure on the front side and the pressure on the back side of the main valve element (eliminating the differential pressure load acting on the main valve element), making it easier to open the valve.

[0017] Furthermore, in the above solenoid valve, when the seal diameter formed when the main valve element sits on the main valve seat is referred to as the "first seal diameter," the seal diameter formed when the sub-valve element sits on the sub-valve seat is referred to as the "second seal diameter," and the seal diameter formed by the sealing member is referred to as 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] Furthermore, the sealing member is typically provided between the main valve element and the sub-valve element, for example, between the outer circumferential surface of the main valve element and the inner circumferential surface of the sub-valve element, 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 valve disc's up-and-down movement. In contrast, in the first invention (and the same applies to the second invention described below), when power supply to the drive device (coil) is stopped, the attractive force of the attractor disappears, and the first and second coil springs push the main and sub-valve discs in the valve-opening direction, initiating the valve-opening operation. However, the main and sub-valve discs move together without moving relative to each other throughout most of the stroke from the closed state (when the main and sub-valves are completely closed) to the open state (when the main and sub-valves are fully open). Only when there is a difference in timing between when the main and sub-valve discs leave the main valve seat and when they leave the sub-valve seat at the beginning of the valve-opening operation (i.e., only during the very short time or stroke from when the main or sub-valve is closed to when it opens slightly) does the main and sub-valve discs move relative to each other, generating sliding resistance. Therefore, according to the present invention, the sliding resistance generated by the seal member can be reduced compared to conventional techniques. 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 unit. In addition, since the valve can be opened even when there is a high differential pressure between the inlet and outlet passages, it is easy to use high-pressure fluids.

[0020] [Second Invention] A pilot operated 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 element that moves toward and away from the main valve seat to open and close the main valve port; a pilot passage that passes through the main valve element and selectively communicates the pilot valve chamber with the outflow path; a pilot valve port having a pilot valve seat and formed at the end of the pilot passage on the pilot valve chamber side; a pilot valve element that moves toward and away from the pilot valve seat to open and close the pilot valve port; a pressure equalizing passage that communicates the main valve chamber with the pilot valve chamber; and a drive device including a plunger and a attractor that attracts the plunger.

[0021] The pilot-operated solenoid valve further comprises: an auxiliary valve chamber which includes a back pressure chamber formed between the pilot valve element and the attractor and is formed so as to be interposed between the pilot valve chamber and the attractor and which selectively communicates with the pilot valve chamber; an auxiliary valve port which has an auxiliary valve seat and which communicates the pilot valve chamber with the auxiliary valve chamber; a auxiliary valve element which is provided so as to be movable relative to the pilot valve element in the axial direction of the solenoid valve and which moves back and forth relative to the auxiliary valve seat to open and close the auxiliary valve port; and a secondary valve element which biases the pilot valve element in a valve opening direction via the auxiliary valve element and which is adapted to be closed by the pilot valve element when the drive device is not driven. and a first coil spring that moves the sub-valve element in a valve-opening direction, a second coil spring that is interposed between the pilot valve element and the sub-valve element and that 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 that 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 that connects the sub-valve chamber and the outflow passage via a pilot passage when the pilot valve port is closed by the pilot valve element. Also, the valve may be configured so that when the drive device is driven, it 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 aspect of the present invention, a valve provided in a pilot valve chest, including a pilot valve element, a pilot valve seat, and a pilot valve port, and which opens and closes a pilot passage is referred to as a "pilot valve." Furthermore, with regard to the pilot passage, "selectively communicating the pilot valve chest with the outflow passage" means that the pilot valve chest with the outflow passage is communicated only when the pilot valve is open, and is not communicated with when the pilot valve is closed. Furthermore, with regard to the sub-valve chest, "selectively communicating with the pilot valve chest" means that the pilot valve chest with the sub-valve chest is communicated only when the sub-valve is open, and is not communicated with when the sub-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 larger than that of a direct-acting system, according to the second invention, the valve diameter can be made even larger than that of conventional pilot-type solenoid valves.

[0024] Also, in the solenoid valve according to the second invention, when the seal diameter formed when the pilot valve element sits on the pilot valve seat is referred to as the "first seal diameter," the seal diameter formed when the sub-valve element sits on the sub-valve seat is referred to as the "second seal diameter," and the seal diameter formed by the seal member is referred to as the "third seal diameter," it is preferable that the first seal diameter, the second seal diameter, and the third seal diameter are the same. This is to eliminate the differential pressure load acting on the main valve element when the valve is closed, making it easier to open the valve, just like the first invention. [Effects 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, which is given with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a vertical cross-sectional view showing an open state of a solenoid valve according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged longitudinal cross-sectional view showing the main valve and sub-valve portion (portion B in FIG. 1) when the solenoid valve according to the first embodiment is in an open state. [Figure 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 longitudinal 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. [Figure 5] FIG. 5 is a vertical cross-sectional view showing an open state of a solenoid valve according to a second embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged longitudinal cross-sectional view showing the pilot valve and 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 cross-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 INVENTION

[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. This first embodiment embodies the first aspect of the present invention.

[0029] As shown in Figures 1 to 4, the solenoid valve 11 according to 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 element 16 and a sub-valve element 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 element 16 and the sub-valve element 29 provided on the upper surface of the flow path block 12.

[0030] The flow path block 12 has a bottomed and open vertical hole (open at the top and having a bottom at the bottom) that extends vertically downward (i.e., in the direction of the axis A of the solenoid valve 11) from the top surface of the flow path block 12, and a sub-valve seat member (hereinafter simply referred to as the "sub-valve seat") 31 is installed to separate the interior of this vertical hole into upper and lower spaces (an upper space and a lower space). The sub-valve seat 31 is a flat ring-shaped member with a central hole that becomes the sub-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 sub-valve seat 31 is structured with a rubber coating on the top surface of a metal plate to improve refrigerant blocking properties (to prevent valve leakage).

[0031] The lower space of the vertical hole serves as the main valve chamber 13, and an inlet passage 14 for allowing the refrigerant to flow into the main valve chamber 13 is opened to the side of the main valve chamber 13. An outlet passage 15 for allowing the refrigerant to flow out of the main valve chamber 13 is opened to the bottom of the main valve chamber 13. A main valve seat member (hereinafter simply referred to as the "main valve seat") 20, with which the main valve element 16 comes into and out of contact with (abuts against and separates from) the main valve port 19, which is the opening of the outlet passage 15 into the main valve chamber 13. The main valve seat 20 is a flat ring-shaped member with a central hole, similar to the sub-valve seat 31. The main valve seat 20 is constructed with rubber coatings on both sides (top and bottom) of the metal plate to improve 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 forms an auxiliary valve chamber 30 including a back pressure chamber 34 in the upper space.

[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 underside of the flange portion 25b.

[0034] The guide portion 25c accommodates the sub-valve element 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 this male thread is threaded into a female thread formed on the inner peripheral surface of the connection opening 21 (upper part of the vertical hole), and the guide portion 25c is screwed into the connection opening 21 to fix the suction member 25 to the flow path block 12. 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 refrigerant from leaking from the main valve chamber 13 to the outside.

[0035] The aspirator body 25a has a cylindrical shape with a central hole 25d that penetrates vertically. 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 a plunger 24 therein so that it can slide vertically. The plunger 24 has a disk-shaped bottom 24a and a ring-shaped peripheral wall 24b that rises upward from the outer periphery of the bottom 24a. A guide member 26 is inserted into the peripheral wall 24b from above. The plunger 24 is guided by this guide member 26 and the inner peripheral surface of the sleeve 23, allowing it to slide vertically smoothly without tilting. 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 magnetic force generated by a coil 39 included in the drive unit 38, and is provided with a shaft 27 that is inserted into the central hole 25d from above the attractor body 25a. The shaft 27 is a rod-shaped member, and its upper end is connected (fixed) to the bottom 24a of the plunger 24. Meanwhile, a connecting member 28 is provided on the underside of the attractor body 25a so that vertical force 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 connects 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 within the central hole 25a.

[0037] The sub-valve element 29 housed within the guide portion 25c has an overall cylindrical shape with openings on the top and bottom surfaces. The base 28a of the connecting member 28 is connected and fixed to the opening on the top surface. The opening on the bottom 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 element 29 toward the center (axis A) of the sub-valve element 29. In addition, the underside of the bottom plate portion is formed with a ring-shaped protrusion portion 29c that protrudes vertically downward, 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 the main valve port 19 by moving toward and away from the main valve seat 20, a valve stem 16b that supports the main valve body 16a, and a head portion 16c that is formed at the upper end of the valve stem 16b so as to have a larger diameter than the valve stem 16b. The main valve body 16a is fixed to the lower end of the valve stem 16b. The main valve element 16 also has an inlet passage 17 that vertically penetrates the main valve body 16a, the valve stem 16b, and the head portion 16c and connects the upper side of the main valve element 16 with the lower side of the main valve element 16 (i.e., connects the outflow passage 15 with the sub-valve chamber 30 when the main valve port 19 is closed by the main valve element 16).

[0039] The main valve element 16 is connected to the sub-valve element 29 so as to be movable relative to it in the vertical direction. Specifically, the head portion 16c of the main valve element 16 is housed in the lower part of the internal space of the sub-valve element 29, the valve stem portion 16b of the main valve element 16 penetrates the bottom plate portion 29b of the sub-valve element 29, and the main valve body 16a is disposed below (below) the sub-valve seat 31. The head portion 16c of the main valve element 16 is slidable in the vertical direction along the inner circumferential surface of the side wall 29a of the sub-valve element 29. In other words, the guide portion 25c of the suction element 25, the sub-valve element 29, and the main valve element 16 (head portion 16c) are nested, and each component (the guide portion 25c and the sub-valve element 29, and the sub-valve element 29 and the main valve element 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 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 (the upper surface of the main valve body 16a) and the sub-valve element 29 (the 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 its home position (the position where the main valve element 16 is most depressed relative to the sub-valve element 29) when the valve is open. The second coil spring 37 is disposed so as to pass through a 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 mounted forms 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, forms 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 seat 31, is referred to as the "sub-valve outer chamber." 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] Additionally, 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 the same (see FIG. 4). This is to eliminate (reduce to 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 state, making it easier to open the valve.

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

[0048] Therefore, in the open valve state, the refrigerant that has flowed into the main valve chamber 13 through the inlet passage 14 flows out through the main valve port 19 and the outlet 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, and this refrigerant enters the back pressure chamber 34 through the communication hole 35 formed in the side wall 29a of the sub-valve element 29, and then passes through the introduction passage 17 of the main valve element 16 and the main valve chamber 13 (the space directly above the main valve port 19) in this order, before being discharged out of the outlet passage 15 to the outside.

[0049] When current is applied to the coil 39 in the above-described valve-open state, the plunger 24, connecting member 28, and sub-valve element 29 are attracted to the attractor body 25a, and are thereby pushed downward together with the plunger 24, connecting member 28, and sub-valve element 29 against the biasing force of the first coil spring 36. At this time, the main valve body 16a receives a downward (valve-closing direction) force from the sub-valve element 29 via the second coil spring 37, and the main valve element 16 moves downward together with (integrally with) the sub-valve element 29. Then, as the main valve element 16 moves downward, it 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 descend, it seats on the sub-valve seat 31, as shown in Figure 4, closing the sub-valve and achieving a completely closed state in which both the main valve and the sub-valve are closed. In this closed state, it is preferable to leave a small gap (air gap) between the suction element body 25 and the plunger 24. This is to ensure that the valve elements (main valve element 16 and sub-valve element 29) are securely seated (contacted) on their respective seats (main valve seat 20 and sub-valve seat 31) when the valve is closed, preventing valve leakage. It is preferable to make this air gap as small as possible in order to increase the force that maintains the closed state (the force pressing the valve elements 16 and 29 against their respective seats 20 and 31).

[0051] In the closed valve state, all flow paths from the inlet path 14 to the outlet 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 closed valve state, the low pressure in the outlet 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 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-described closed valve state, the attractive force with which the attractor body 25a attracts the plunger 24 disappears. As a result, the sub-valve element 29 is lifted by the biasing force of the first coil spring 36, and the head portion 16c of the main valve element 16 is pulled up by the bottom plate portion 29b, causing the main valve element 16 to move upward. At this time, because the differential pressure load acting on the upper and lower surfaces of the main valve element 16 is canceled as described above, the main valve element 16 can be more reliably lifted 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. This second embodiment embodies the second invention.

[0054] The solenoid valve 41 according to the second embodiment of the present invention is a normally open solenoid valve that is in an open state when not energized, and is a pilot-operated solenoid valve that controls the main valve with a pilot valve. While a sub-valve was provided for the main valve in the first embodiment, a similar sub-valve is provided for the pilot valve in this embodiment. In the following description, the same components as those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted, with the focus being 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 inlet passage 14 for introducing a fluid into the main valve chamber 13 and an outlet passage 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 outlet passage 15 on the main valve chamber 13 side so as to open to the main valve chamber 13; a main valve element 16 that moves forward and backward relative to the main valve seat 42 to open and close the main valve port 19; and a valve element that passes through the main valve element 16 and selectively connects the pilot valve chamber 48 and the outlet passage 15. 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 element 47 that moves back and forth relative to the pilot valve seat 49 to open and close the pilot passage 45; a pressure equalizing path 46 that connects the main valve chamber 13 and the pilot valve chamber 48; and an electromagnetic drive device (drive device) 38 that includes a plunger 24 and an attractor (attractor body 25a) that attracts the plunger 24 and drives the pilot valve element 47.

[0056] The main valve element 16 is supported so as to be slidable in the vertical direction by a main valve guide member 43 installed in the opening on the top surface of the flow path block 12. That is, the main valve guide member 43 has a central hole that passes through in the vertical direction, and the upper part of the main valve element 16 is fitted into the lower part of this 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) that urges the main valve element 16 upward (in the valve opening direction). Note that each of the above configurations is similar to that of a conventional pilot-type solenoid valve.

[0057] On the other hand, unlike conventional pilot-type solenoid valves, the solenoid valve of this embodiment is provided with a sub-valve in the pilot valve. The configuration related to this sub-valve is similar to the configuration provided in the main valve of the first embodiment, and the solenoid valve 41 of this embodiment also includes a sub-valve body 29, a sub-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, a sub-valve chamber 30 including a sub-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 was fixed to the flow path block 12, but in this embodiment, since the pilot valve is equipped with a sub-valve, the suction member 25 is fixed to the main valve guide member 43 (at the top 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 inlet passage 17 that introduces the low pressure in the outflow passage 15 into 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 inlet passage 17 directly communicates with the outflow passage 15 when the valve is closed, in this embodiment the inlet passage 17 communicates with the outflow passage 15 via the 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 element 47, i.e., inside the back pressure chamber 34. This second coil spring 37 urges the pilot valve element 47 downward and also urges the sub-valve element 29 upward via the connecting member 28, thereby returning the pilot valve element 47 to its home position (the position where the pilot valve element 47 is most depressed relative to the sub-valve element 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 element 29 and the function of transmitting the upward force from the sub-valve element 29 to the shaft 27) is the same as that of the connecting member 28 in the first embodiment.

[0062] Furthermore, in this embodiment as well, 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 all made the same (see FIG. 8). This is to eliminate (reduce to zero) the differential pressure load (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 valve closed state, making it easier to open the pilot valve.

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

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

[0065] Furthermore, in the open valve state, the pilot passage 45 is open, and the refrigerant that flows from the inlet 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 passes through the pilot passage 45 and is discharged from the outlet passage 15. 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 inlet passage 14 into the main valve chamber 13 (see arrow F) flows out from the outlet passage 15 (see arrow F).

[0066] When current is applied to the coil 39 in the above-described valve open state, the plunger 24, connecting member 28, and sub-valve element 29 are attracted to the attractor body 25a, and are thereby pushed downward together with the plunger 24, connecting member 28, and sub-valve element 29 against the biasing force of the first coil spring 36. At this time, the pilot valve element 47 receives a downward (valve closing direction) force from the connecting member 28 via the second coil spring 37, and the pilot valve element 47 moves downward together with (integrally with) the sub-valve element 29. Then, as the pilot valve element 47 moves downward, it seats 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 descend, it seats on the sub-valve seat 31 as shown in Figure 8, closing the sub-valve and resulting in both the pilot valve and the sub-valve being closed. As in the first embodiment, it is preferable to leave a small gap (air gap) between the suction element body 25 and the plunger 24 in this state. This is to ensure that the valve elements (pilot valve element 47 and sub-valve element 29) are in secure contact with the seats (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 released through the pilot passage 45, causing the pressure in the pilot valve chamber 48 to increase. 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 fully closed valve state.

[0069] Furthermore, in the 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, and 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 fully closed valve state, the attractive force with which the attractor body 25a attracts the plunger 24 disappears. As a result, the sub-valve element 29 is lifted by the biasing force of the first coil spring 36, and the pilot valve element 47 is pulled up by the bottom plate portion 29b. At this time, because the differential pressure load acting on the upper and lower surfaces of the pilot valve element 47 is canceled as described above, the pilot valve element 47 can be more reliably lifted 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 through the pilot passage 45 to the outflow passage 15, 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 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 exerts a biasing force that pulls the main valve element 16 upward. As a result, the main valve element 16 is pushed up and separated from the main valve seat 42, resulting in an open valve state in which the main valve port 19 is opened (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 Third 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 25c guide part 25d Center hole of the suction body 26 Guide member 27 Shaft 28 Connecting member 28a Base of connecting member 28b Rod portion of connecting member 29 Sub-valve body 29a Side wall of sub-valve body 29b Bottom plate of sub-valve body 29c protrusion 30 Sub-valve chamber 31 Sub-valve seat member 32 Sub-oral Oratory 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 Equalization Road 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 in and an outflow path through which the fluid flows out; a main valve port having a main valve seat and disposed between the outflow passage and the main valve chamber so as to open into the main valve chamber; a main valve body that moves back and forth relative to the main valve seat to open and close the main valve port; a drive device including a plunger and a suction element that attracts the plunger; A solenoid valve comprising: an auxiliary valve chamber including a back pressure chamber formed between the main valve element and the suction element, the auxiliary valve chamber being interposed between the main valve chamber and the suction element and selectively communicating with the main valve chamber; a sub-valve port having a sub-valve seat and communicating the main valve chamber with the sub-valve chamber; a sub-valve element that is movable relative to the main valve element in the axial direction of the solenoid valve and moves back and forth with respect to the sub-valve seat to open and close the sub-valve port; a first coil spring that biases the main valve element in a 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; a second coil spring interposed between the main valve body and the sub-valve body to urge the main valve body in a valve closing direction and to urge the sub-valve body in a valve opening direction; a seal member capable of blocking the flow of 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 first seal diameter formed by the main valve body being seated on the main valve seat; a seal diameter formed by the sub-valve body being seated on the sub-valve seat is a second seal diameter; The seal diameter by the seal member is a third seal diameter, When we refer to them as The first seal diameter, the second seal diameter, and the third seal diameter are made to be the same.

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

4. a flow path block having a main valve chamber and a pilot valve chamber therein, and having an inlet passage for introducing a fluid into the main valve chamber and an outlet passage for discharging a fluid from the main valve chamber; a main valve port having a main valve seat and disposed between the outflow passage and the main valve chamber so as to open into the main valve chamber; a main valve body that moves back and forth relative to the main valve seat to open and close the main valve port; a pilot passage that passes through the main valve body and selectively connects the pilot valve chamber and the outflow passage; a pilot valve port having a pilot valve seat and formed at an end of the pilot passage on a pilot valve chamber side; a pilot valve body that moves back and forth relative to the pilot valve seat to open and close the pilot valve port; a pressure equalizing passage that communicates the main valve chamber and the pilot valve chamber; a drive device including a plunger and a suction element that attracts the plunger; A pilot-operated solenoid valve comprising: a sub-valve chamber including a back pressure chamber formed between the pilot valve body and the attractor, the sub-valve chamber being interposed between the pilot valve chamber and the attractor and selectively communicating with the pilot valve chamber; a sub-valve port having a sub-valve seat and communicating the pilot valve chamber with the sub-valve chamber; a sub-valve element that is movable relative to the pilot valve element in the axial direction of the solenoid valve and moves back and forth with respect to the sub-valve seat to open and close the sub-valve port; a first coil spring that biases the pilot valve element in a valve opening direction via the sub-valve element, and moves the pilot valve element and the sub-valve element in the valve opening direction when the drive device is not driven; a second coil spring interposed between the pilot valve body and the sub-valve body to urge the pilot valve body in a valve closing direction and to urge the sub-valve body in a valve opening direction; a seal member capable of blocking 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; an introduction passage that communicates the sub-valve chamber with the outflow passage via the pilot passage when the pilot valve port is closed by the pilot valve body; A solenoid valve comprising:

5. When driven, the drive device moves the sub-valve element in a 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.

5. The pilot-operated solenoid valve according to claim 4.

6. a first seal diameter formed by the pilot valve body being seated on the pilot valve seat; a seal diameter formed by the sub-valve body being seated on the sub-valve seat is a second seal diameter; The seal diameter by the seal member is a third seal diameter, When we refer to them as The first seal diameter, the second seal diameter, and the third seal diameter are made to be the same.

6. The pilot-operated solenoid valve according to claim 4 or 5.

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