SOLENOID VALVE

Abstract

Solenoid valve (10; 210) used in a gas flow path, with: a coil (30); a valve element receiving section (32; 232) which is placed inside the coil (30); a valve element (20; 20a; 20b; 120; 320) which is placed within the valve element receiving section (32; 232) and is configured to be moved in an axial direction with the supply of electricity to the coil (30); a valve section (45) which is configured to open and close the gas flow path accompanied by the movement of the valve element (20; 20a; 20b; 120; 320), wherein either a surface of the valve element (20; 20a; 20b; 120; 320) opposite the valve element receiving section (32; 232) or a surface of the valve element receiving section (32; 232) opposite the valve element (20; 20a; 20b; 120; 320) having a first groove (21, 221) extending in the axial direction, and a second groove (22, 222, 322) arranged to intersect with the first groove (21, 221) and to extend in a circumferential direction, and the first groove (21, 221) is formed, extending at least from the second groove (22, 222, 322) to one side of the valve section, wherein the first groove (21) and the second groove (22, 322) are formed in the valve element (20; 20a; 20b; 320), and the first groove (21) is formed to extend in the axial direction from a valve section-side end of the valve element (20; 20a; 20b; 320), and wherein the valve element (20; 20a; 20b; 320) is configured such that a length in the axial direction between the second groove (22, 322) and the valve section-side end of the valve element (20; 20a; 20b; 320) is shorter than a length in the axial direction between the second groove (22, 322) and an end on the opposite side of the valve element (20; 20a; 20b; 320) that is opposite the valve section side.

Description

BACKGROUND

[0001] The present disclosure relates to a solenoid valve. STATE OF THE ART

[0002] A solenoid valve is generally used to switch the flow path of a fluid. A known configuration of the solenoid valve generally has a coil, a valve element configured to be moved in an axial direction by the supply of electricity to the coil, and a valve section configured to be opened and closed accompanied by the movement of the valve element (as described, for example, in JP 2002 - 372 164 A).

[0003] Document US 9,068,577 B2 discloses a solenoid valve. According to this disclosure, a valve element has a flattened section on two sides in the axial direction of the valve element, formed as a straight-cut section. In the circumferential direction, a small-diameter portion is disclosed.

[0004] Document US 9,346,447 B2 discloses a valve element. The valve element has a spiral through-hole. Through-holes are provided in a housing of the disclosed valve to allow air to pass through and be discharged to the outside.

[0005] German patent application DE 10 2004 040 476 A1 discloses a capacity control valve. This valve has a small-diameter section in a piston head. Axially extending grooves are formed in this small-diameter section.

[0006] German patent application DE 60 2004 003 517 T2 discloses a valve with axially extending grooves. A small-diameter section is connected to the groove via a step.

[0007] If the fluid flowing in the flow path provided by the solenoid valve is a gas, liquid water may be present in the gas. In this case, it is very likely that the liquid water contained in the gas will enter the solenoid valve. If liquid water enters the interior of the solenoid valve, a temperature drop will likely cause the liquid water to freeze inside the solenoid valve, hindering the valve's opening and closing processes and thus preventing normal operation. To facilitate the formation of a magnetic path during the process of supplying electricity to the coil, a small gap is generally provided in the solenoid valve between the valve element and an external element (socket).It is more likely that liquid water will freeze in such a narrow space between the valve element and the bushing. Therefore, there is a need for a technology that reduces solenoid valve malfunction caused by liquid water freezing when it enters a space around the valve element. The object of the invention is to provide such a solenoid valve.

[0008] The object of the invention is achieved by a solenoid valve according to claim 1 or claim 4. Advantageous embodiments are the subject of the dependent claims. SUMMARY

[0009] (1) According to one aspect of the present disclosure, a solenoid valve used in a gas flow path is provided. The solenoid valve comprises a coil; a valve element receiving section located within the coil; a valve element located within the valve element receiving section, configured to be moved in an axial direction with a supply of electricity to the coil; and a valve section configured to open and close the gas flow path accompanied by the movement of the valve element. Either a surface of the valve element opposite the valve element receiving section, or a surface of the valve element receiving section opposite the valve element, has a first groove extending in the axial direction and a second groove arranged to intersect the first groove and extending in a circumferential direction.The first groove is designed to extend at least from the second groove to one side of a valve section.

[0010] Even if liquid water present in a gas supplied to the solenoid valve enters and freezes into a free space between the valve element and the valve element receiving section, the configuration of the solenoid valve in this respect reduces a malfunction of the solenoid valve caused by the freezing of the water.

[0011] (2) In the solenoid valve of the above-described point, the first groove and the second groove are formed in the valve element, and the first groove is designed to extend axially from a valve-section-side end of the valve element. The configuration of the solenoid valve of this point also facilitates the discharge of water from the first groove and the second groove, thereby reducing a potential problem caused by the freezing of the liquid water.

[0012] (3) In the solenoid valve of the view described above, the valve element is configured such that the axial length between the second groove and the valve section-side end of the valve element is shorter than the axial length between the second groove and an opposite side end of the valve element, which is opposite the valve section side. This configuration of the solenoid valve allows water entering the space between the valve element and the valve element receiving section to be immediately distributed circumferentially through the second groove. This configuration also facilitates the removal of a valve element fixation caused by freezing of the incoming liquid water.The second groove, which is configured to have a wider distance between the valve element and the valve element receiving section, serves to immediately retain the incoming liquid water, thereby preventing the incoming liquid water from freezing.

[0013] (4) The solenoid valve of the foregoing view may also include a magnetic path forming element having a base surface section located axially on the valve section side of the coil, which forms part of a magnetic path in the base surface section when electricity is supplied to the coil. One end of the base surface section near the valve element receiving section may be located on the valve section side of a valve section-side end of the second groove in a closed valve position of the valve section. The configuration of the solenoid valve of this view also reduces the distance between the end of the base surface and the valve element in the open valve position. This configuration makes it easier to form the magnetic path during the process of supplying electricity to the coil in the closed valve position, thereby reducing power consumption.

[0014] (5) In the solenoid valve of the first consideration, the first groove and the second groove are alternatively formed in the valve element receiving section, and a valve section-side end of the first groove is arranged on the valve section side of a valve section-side end of the valve element in an open valve position of the valve section. The configuration of the solenoid valve of this consideration also facilitates the discharge of water from the first groove and from the second groove and reduces a potential problem caused by the freezing of the liquid water.

[0015] (6) In the solenoid valve of the above-described design, a valve-section-side end of the second groove on the valve section side can be arranged at a center in the axial direction of the valve element in the open position of the valve section. Even if liquid water enters from the valve section side into the space between the valve element and the valve element receiving section, the configuration of the solenoid valve of this design allows the entering liquid water to be introduced into the second groove more quickly. This configuration improves the beneficial effect of reducing the problem of the valve element becoming stuck when the liquid water freezes.

[0016] (7) In the solenoid valve of the foregoing described aspect, an opposite side end of the first groove, which is opposite the side of the valve section, may be arranged to overlap with the second groove. The configuration of the solenoid valve of this aspect allows liquid water penetrating into the free space between the valve element and the valve element receiving section to be introduced more effectively in the circumferential direction and also facilitates the removal of a fixation of the valve element caused by freezing of the water.

[0017] The disclosure can be implemented in any other aspect than the solenoid valve described above, for example a valve element for solenoid valve, a valve element receiving section for the solenoid valve, a valve element receiving section for the solenoid valve, or a method to make a solenoid valve frost-proof. BRIEF DESCRIPTION OF THE DRAWINGS The Fig. Figure 1 is a sectional view showing a solenoid valve according to a first embodiment in a closed position; the Fig. Figure 2 is a sectional view showing the solenoid valve according to the first embodiment in an open valve position; the Fig. Figure 3 is a view that shows a magnified view of the appearance of a piston; the Fig. Figure 4 is a sectional view showing the configuration of a solenoid valve according to a comparative example; the Fig. Figure 5 is a view showing a magnification of a section with a coil and a piston; the Fig. Figure 6 is a sectional view showing a configuration of the piston; the Fig. Figure 7 is a sectional view showing a different configuration of the piston; the Fig. Figure 8 is a sectional view showing a different configuration of the piston; the Fig. Figure 9 is a sectional view showing a solenoid valve according to a second embodiment in an open valve position; the Fig. Figure 10 is a view showing a magnification of a section with a bushing and a piston; the Fig. Figure 11 is a view that depicts the appearance of a piston according to a modification. DETAILED DESCRIPTION A. First embodiments

[0018] The Fig. 1 and Fig. Figure 2 are sectional views depicting a solenoid valve 10 according to a first embodiment of the following disclosure. Fig. Figure 1 shows the solenoid valve 10 in a closed position, and the Fig. Figure 2 shows the solenoid valve 10 in an open position.

[0019] According to the embodiment, the solenoid valve 10 is provided in a fuel cell vehicle equipped with a fuel cell system comprising a hydrogen tank and a fuel cell. The solenoid valve 10 is used to switch a flow path configured to supply hydrogen from outside the fuel cell vehicle to the hydrogen tank and a flow path configured to supply hydrogen from the hydrogen tank to the fuel cell. The solenoid valve 10 of the embodiment has a coil 30, a main body part 37, a piston 20, a valve section 45, a yoke 34, a spring 31, a stop 38, and a housing 36. The coil 30, the main body part 37, the piston 20, the valve section 45, the yoke 34, the spring 31, and the stop 38 are located in the housing 36. In the sectional views of the Fig. 1 and Fig. Figure 2 shows piston 20 not in cross-section, but in its form and appearance.

[0020] The excitation and demagnetization of coil 30 are controlled by regulating the supply of electricity to coil 30. Coil 30 is positioned in the yoke 34 in an approximately cylindrical shape. The yoke 34 forms part of a magnetic path along the path of the electricity supply to coil 30. The yoke 34 is also referred to as a magnetic path forming element.

[0021] The piston 20 is a magnetic body and is configured to move according to the excitation and demagnetization of the coil 30. In the following description, a direction along a central axis of the piston 20 and the coil 30 is referred to as an axial direction. A direction perpendicular to the axial direction is referred to as a horizontal direction. With respect to the horizontal direction, a direction passing through the central axis is specifically referred to as a radial direction. With respect to the axial direction, a direction in which the piston 20 moves according to the excitation of the coil 30 is referred to as a valve opening direction and is further specified as an X-direction. Fig. 1 and Fig. Figure 2 shows the solenoid valve 10 of the embodiment, which is characterized by a surface configuration of the piston 20. The surface configuration of the piston 20 will be described in detail later. The piston 20 is also referred to as the valve element.

[0022] The spring 31 has one end mounted on the piston 20 and serves to push the piston 20 in a direction opposite to the valve opening direction. In the following description, with reference to the axial direction, the direction opposite to the valve opening direction is also referred to as a valve closing direction and is described in the Fig. 1 and Fig. 2 shown as a Y direction.

[0023] The main body part 37 has a bushing 32 and a base section 33. The bushing 32 is an approximately cylindrical section of the main body part 37 located inside the coil 30, and the base section 33 is a section of the main body part 37 located on a Y-direction side of the coil 30 and configured to form a flow path (described later) within it. A connection space 44 is formed inside the main body part 37, and the piston 20 is received in this connection space 44. The bushing 32 is an element opposite a side face of the piston 20. The bushing 32 is also referred to as the valve element receiving section.

[0024] A plurality of flow paths are formed within the base section 33 and are configured to be continuous with a flow path formed within the housing 36. More precisely, flow paths 40 to 42 are configured as flow paths formed within the base section 43 to be continuous with the flow path formed within the housing 36. Flow path 40 is arranged to be connected to a hydrogen tank (not shown) and to the connecting chamber 44, and is configured to introduce high-pressure hydrogen gas, supplied by the hydrogen tank, into the connecting chamber 44.Flow path 41 is arranged to be connectable to an anode-side flow path of a fuel cell (not shown) and to the connection chamber 44, and is configured to supply hydrogen from the hydrogen tank to the connection chamber 44 via flow path 40 to the fuel cell when the solenoid valve 10 is open. Flow path 42 is arranged to be connected to an on / off valve (not shown) and to the connection chamber 44. The on / off valve is normally closed and is opened to discharge hydrogen gas from the connection chamber 44 to the outside.

[0025] The stop 38 is fixed inside the coil 30 and, in combination with the bushing 32, forms part of a wall surface of the connection space 44, as described above. The other end of the spring 31 is attached to the stop 38.

[0026] The valve section 45 has a valve element guide end 23 and a valve seat 35. The valve element guide end 23 is provided at a Y-direction end of the piston 20. The valve seat 35 is provided on an inner wall surface of the main body part 37 (base section 33) to be opposite the valve element guide end 23 and is positioned on the valve element guide end 23 within a surface in a system where the flow path 41 is open. More precisely, the valve seat 35 is provided to surround the entire outer circumference of the opening of the flow path 41. The valve seat 35 can be made, for example, of rubber or resin. The solenoid valve 10 is closed when the valve element guide end 23 is seated on the valve seat 35 and is open when the valve element guide end 23 is separated from the valve seat 35.This opens and closes a gas flow path, causing flow path 40 and flow path 41 to be connected.

[0027] The Fig. Figure 1 represents the state of demagnetization of the solenoid valve 10, that is, the state in which no electric current flows into the coil 30 and no suction force is generated to pull the piston 20. In this state, the valve section 45 and the spring 31 are closed, so that hydrogen gas is not supplied to the fuel cell on the side of the flow path 41 in the connecting chamber 44.

[0028] The Fig. Figure 2 represents the state of excitation of the solenoid valve 10, that is, the state in which electric current flows into the coil 30. In this state, the valve section 45 is open such that hydrogen gas supplied from the hydrogen tank to the connecting chamber 44 via flow path 40 is supplied to the fuel cell via flow path 41.

[0029] The Fig. Figure 3 is a magnified view of the piston 20. The piston 20 has a first groove 21 and a second groove 22, which are provided on its side face, or more precisely, on a surface opposite the bushing 32. The first groove 21 is a groove extending axially from the Y-direction end (end at the side of the valve section 45) of the piston 20 to the X-direction side. The second groove 22 is an annular groove arranged to intersect with an X-direction end of the first groove 21 and extending circumferentially around the piston 20.

[0030] The piston 20 of this embodiment is formed in an approximately column-like shape. A remaining portion of the piston 20, other than the portion containing the first groove 21 and the second groove 22, is formed to have a substantially identical outer diameter. Accordingly, the portion of the piston 20 containing the first groove 21 and the second groove 22 has a greater distance from the bushing 32, which serves as the valve element receiving section, compared to the remaining portion of the piston 20.

[0031] Even if liquid water contained in the gas supplied to the solenoid valve 10 enters a free space between the pistons 20 and the bushing 32 and freezes, the configuration of the solenoid valve 10 in the embodiment described above reduces a malfunction of the solenoid valve 10 caused by the freezing of the water. The following describes in greater detail a reduction of the malfunction of the solenoid valve 10 caused by the freezing of the water.

[0032] The Fig. Figure 4 is a sectional view showing the configuration of a solenoid valve 110 with a piston 120 instead of the piston 20 as a comparative example. The solenoid valve 110 has a similar configuration to that of the solenoid valve 10, except for the piston 120. The same components are designated by the same reference numerals and are not described in detail here. In the sectional view of the Fig. Figure 4 shows the piston 120 not in cross-section, but in its appearance.

[0033] As from the Fig. As can be seen in Figure 4, the piston 120 has a flat side surface without the first groove 21 and the second groove 22, so that the side surface of the piston 120 approaches the bushing 32 uniformly. Liquid water penetrating the space between the piston 120 and the bushing 32 is accordingly distributed over a wide area of ​​the space in both the axial and circumferential directions. If this liquid water freezes, the frozen water impedes the movement of the piston 20 in the axial direction, and it is therefore likely to cause a malfunction of the solenoid valve 110.

[0034] In the solenoid valve 10 of the embodiment, the piston 20 is provided with the first groove 21 and the second groove 22. When a small volume of liquid water enters the free space between the piston 20 and the bushing 32, the incoming liquid water W is retained in the first groove 21 and the second groove 22, as shown in the Fig. 1 and Fig. As can be seen in Figure 2. This configuration accordingly prevents the intruding liquid water W from being distributed in the free space between the piston 20 and the bushing 32. Even if the intruding liquid water freezes, this configuration prevents any obstruction of the movement of the piston 20 in the axial direction caused by the frozen water.

[0035] Even if the volume of liquid water that has entered the space between the pistons 20 and the bushing 32 increases to fill the entire capacity of the first groove 21 and the second groove 22, the greater distance between the area of ​​the piston 20 containing the first groove 21 and the second groove 22 and the bushing 32 serves to retain the liquid water. This configuration prevents the liquid water from spreading to the remaining area of ​​the piston 20, which has the shorter distance to the bushing 32. The liquid water, which is present as a larger mass in the wider space, is less likely to freeze compared to the liquid water, which is thinly distributed in the narrower space.Accordingly, the configuration which causes the liquid water to be held by the first groove 21 and the second groove 22 effectively reduces a malfunction of the solenoid valve 10 caused by the freezing of the liquid water.

[0036] In the solenoid valve 10, the circumferentially extending second groove 22 serves to introduce liquid water penetrating the free space between the piston 20 and the bushing 32 in the circumferential direction, thereby preventing the liquid water from spreading in the axial direction. If the liquid water in the free space between the piston 20 and the bushing 32 freezes, the smaller area in which the frozen water is distributed in the axial direction makes it easier to remove the piston 20's fixing, which is caused by the water freezing when the piston 20 is moved axially. This configuration allows liquid water to be introduced in the circumferential direction. Even if the liquid water freezes, this configuration correspondingly facilitates the removal of the piston 20's fixing and reduces a potential problem caused by the water freezing.

[0037] The presence of the second groove 22, in addition to the first groove 21 in the piston 20, facilitates the discharge of liquid water that enters the free space between the piston 20 and the bushing 32. This improves the beneficial effect of reducing the malfunction of the solenoid valve 10 caused by the freezing of the liquid water. When hydrogen gas is supplied to the solenoid valve 10 under high pressure, the hydrogen gas forms a flow that enters the free space between the piston 20 and the bushing 32. It flows in the X-direction within this free space, then in the Y-direction after reaching the X-direction end near the spring 31, and is discharged from the free space. The first groove 21 formed in the piston 20 serves to discharge any liquid water that accumulates in the first groove 21 and the second groove 22 as the hydrogen gas flows in the Y-direction.

[0038] One strategy to increase the distance between the piston 120 and the bushing 32 can be used for the solenoid valve 110 of the Fig. As illustrated in the comparative example 4, this can be used to reduce the possibility of the incoming liquid water freezing. However, increasing the distance between the piston 120 and the bushing 32 requires a higher electrical current to flow into the coil 30 to pull the piston 120 upwards when the solenoid valve 110 is opened. This strategy increases power consumption and is therefore not preferred. The configuration of the embodiment, however, allows the distance between the piston 20 and the bushing 32 to be sufficiently reduced in the remaining section of the piston 20, which is not the section in which the first groove 21 and the second groove 22 are formed. This configuration reduces the disadvantage of requiring a higher electrical current to flow into the coil 30.

[0039] One reason why liquid water might be present in the hydrogen gas supplied to the solenoid valve 10 could be, for example, the penetration of rainwater from a hydrogen gas supply port in the fuel cell vehicle equipped with the solenoid valve 10 during the process of filling the hydrogen gas into the vehicle's hydrogen tank. Another possible reason is the condensation of water vapor, which is likely present in the hydrogen gas if the supplied hydrogen gas has a relatively low purity. If liquid water is present in the hydrogen gas, it is likely that the liquid water enters the free space between the piston 20 and the bushing 32 due to the pressure of the hydrogen gas during the process of supplying the high-pressure hydrogen gas to the solenoid valve 10.

[0040] One reason why liquid water might freeze in the solenoid valve could be, for example, a decrease in the ambient temperature of the fuel cell vehicle. If a compacted volume of liquid water freezes in the space between the piston 20 and the bushing 32 due to a decrease in ambient temperature during a shutdown of the fuel cell system, it is likely that the frozen water will impede the opening of the solenoid valve 10 upon the next start of the fuel cell system, and thus likely cause a problem in the supply of hydrogen gas to the fuel cell.

[0041] Another reason why liquid water freezes in the solenoid valve 10 could be the low temperature of the hydrogen gas supplied to the solenoid valve 10. This is likely what causes the liquid water to freeze in the solenoid valve 10 when the valve is in the open position. For example, during the process of withdrawing hydrogen gas from the hydrogen tank, which is configured to store high-pressure hydrogen gas, adiabatic expansion of the hydrogen gas in the tank reduces the temperature of the hydrogen gas released from the tank. The continuous supply of low-temperature hydrogen gas further reduces the temperature of the solenoid valve 10, and this is likely what causes the liquid water entering the space between the piston 20 and the bushing 32 to freeze.If the liquid water freezes in the open position of solenoid valve 10, it is likely that the frozen water will prevent the solenoid valve 10 from closing and thus halt power generation in the fuel cell. As a result, this is likely to cause a problem due to the supply of unsolicited hydrogen gas to the fuel cell during a power generation stoppage.

[0042] In the Fig. 3, where distance A denotes a distance between an end on the side of the valve section 45 (Y-direction end) of the piston 20 and the second groove 22, and distance B denotes a distance between an end opposite the side end (X-direction end) of the valve section 45 of the piston 20 and the second groove 22. The end on the side of the valve section 45 of the piston 20 is a Y-direction end of the remaining section of the piston 20, which has an approximately constant distance to the bushing 32 and is not the area in which the first groove 21 and the second groove 22 are provided. According to the embodiment, the valve element guide end 23 is configured to have a reduced diameter. Thus, according to the embodiment, the Y-direction end of the piston 20 defines a boundary between the piston 20 and the valve element guide end 23.

[0043] The ratio between distance A and distance B can be arbitrarily set and can be greater than or equal to distance A. Liquid water penetrates from one Y-direction end of the piston 20 to enter the space between the piston 20 and the bushing 32. The positional ratio of distance A to distance B allows the penetrating liquid water to be introduced into the second groove 22 more quickly. This causes the penetrating liquid water to spread more rapidly in the circumferential direction and suppresses its axial distribution. This also facilitates the removal of the piston 20's fixing, which is caused by the freezing of the penetrating liquid water.Additionally, the positional ratio distance A < distance B allows the liquid water to be retained more quickly in the second groove 22, which is provided in the area of ​​the piston 20 that has a greater distance between the piston 20 and the bushing 32. This configuration prevents the liquid water from freezing and enhances the beneficial effect of reducing a potential problem caused by freezing.

[0044] The Fig. Figure 5 is a view showing a magnified section with the coil 30 and the piston 20 in the Fig. Figure 1 represents the solenoid valve 10. When electricity is supplied to the coil 30, a magnetic path is formed around the coil 30, passing through the piston 20, the stop 38, the bushing 32, and the yoke 34. The positional ratio of these elements can be set arbitrarily, as long as a suction force is generated to move the piston 20 by supplying electricity to the coil 30. However, it is preferred to determine the positional ratio with a view to facilitating the formation of the magnetic path. The following describes the positional ratio between the piston 20 and the yoke 34, configured to place the coil 30 within it and to form part of the magnetic path.

[0045] A magnetic path MP, formed in the process of supplying electricity to the coil 30 to open the solenoid valve 10, is conceptually represented by a dotted line in the Fig. 5 in the closed valve position as in the Fig. Figure 1 shows that the yoke 34 has a bottom surface section 39 positioned axially on the side of the valve section 45 of the coil 30, in addition to a cylindrical section extending axially. More precisely, the bottom surface section 39 of the yoke 34 is designed to cover the end of one side of the valve section 45 (Y-direction end) of the coil 30 and extends radially inward. A dashed line L2 extending from the Fig. As can be seen in Figure 5, this designates a position that overlaps with a Y-direction end of the floor surface section 39 in the horizontal direction at one end of the floor surface section 39 near the socket 32. A dashed line L1, which extends from the Fig. As can be seen in Figure 5, this designates a position which overlaps with a Y-direction end of the second groove 22 in the horizontal direction in the position of the closed valve.

[0046] As from the Fig. As can be seen in Figure 5, the Y-direction end of the base surface section 39 can be positioned at the end of the base surface section 39 near the bushing 32, on the side of the valve section 45 (Y-direction side) of the Y-direction end of the second groove 22 in the closed valve position (that is, placing the dashed line L2 on the Y-direction side of the dashed line L1). This configuration allows the end of the base surface section 39 to be closest to the piston 20 at the position on the Y-direction side of the second groove 22 in the closed valve position. Compared to a configuration where the Y-direction end is closest to the piston 20 at the end of the base surface section 39 at the position of the second groove 22, this configuration reduces the distance between the end of the base surface section 39 and the piston 20.Even when the piston 20 is provided with the second groove 22, this configuration simplifies the formation of the magnetic path in the process of supplying electricity to the coil 30 in the closed valve position and reduces the power consumption of the solenoid valve 10. However, it is not essential to position the dashed line L2 on the Y-direction side of the dashed line L1. Even if this positional ratio is not met, the presence of the first groove 21 and the second groove 22 has the aforementioned beneficial effect of reducing a potential problem caused by water freezing.

[0047] In the configuration where the dashed line L2 is located on the Y-direction side of the dashed line L1 in the closed valve position, even when the piston 20 is drawn in the X-direction to the open valve position, the position of the dashed line L2 on the Y-direction side of the position of the dashed line L1 is maintained (position of the Y-direction end of the second groove 22). In the solenoid valve 10, the area of ​​the piston 20 on the Y-direction side of the second groove 22 can overlap with the end of the bottom surface section 39 in the horizontal direction in both the closed and open valve positions.

[0048] In the solenoid valve 10 of the embodiment, the base surface section 39 is formed as part of the yoke 34. However, this configuration is not limiting, and a different configuration can be used. The solenoid valve can have any configuration as long as the solenoid valve is provided with a magnetic path forming element that forms part of the magnetic path and that has the base surface section 39 arranged on the Y-direction side of the coil 30, and the end of the base surface section 39 is located on the side near the bushing 32 on the Y-direction side of the Y-direction end of the groove 22 formed in the piston 20.

[0049] The Fig. 6, Fig. 7 to Fig. Figure 8 shows sectional views of pistons according to the embodiment and modifications thereof. Fig. Figure 6 is a sectional view showing the piston 20 present in the solenoid valve 10 of the first embodiment, in a VI-VI section of the Fig. 3. The Fig. Figure 6 represents a section of the piston 20 with the first groove 21 and the second groove 22 around the central axis of the piston 20. Fig. 7 is a sectional view showing a piston 20a according to a first modification of the first embodiment in a similar section to that of the Fig. 6 represents the Fig. Figure 8 is a sectional view showing a piston 20b according to a second modification of the first embodiment in a similar section to that of the Fig. 6 represents. In the Fig. 6, Fig. 7 to Fig. 8 denotes a depth T1, the depth of the first groove 21, and T2 denotes the depth of the second groove 22. As can be seen from the Fig. 6, Fig. 7 to Fig. As can be seen in Figure 8, the depth of the first groove 21 and the depth of the second groove 22 can be adjusted as desired.

[0050] As from the Fig. As can be seen in Figure 6, in the piston 20 of the embodiment, the depth T1 of the first groove 21 is equal to the depth T2 of the second groove 22. This configuration simplifies the formation of the first groove 21 and the second groove 22 in the piston 20. This simplification reduces manufacturing costs. As can be seen from the Fig. As can be seen in Figure 7, the depth T1 of the first groove 21 in piston 20a is less than the depth T2 of the second groove 22. This configuration also reduces the distance between the piston as a whole and the bottom surface section 39 of the yoke 34 and facilitates the formation of the magnetic path. A simplified magnetic path reduces the power consumption in the process of supplying electricity to the coil 30. As can be seen from the Fig. As can be seen in Figure 8, in piston 20b the depth T1 of the first groove 21 is greater than the depth T2 of the second groove 22. This configuration makes it easier to discharge the liquid water that has accumulated in the second groove 22 via the first groove 21. This correspondingly improves the beneficial effect of preventing the liquid water that has accumulated between the piston and the bushing 32 from freezing. B. Second embodiment

[0051] The Fig. 9 is a sectional view showing a solenoid valve 210 according to a second embodiment of the present disclosure as the Fig. 1 and Fig. 2 represents. The solenoid valve 210 has a configuration similar to that of the solenoid valve 10 of the first embodiment, except that a piston 120 is used as in the Fig. 4 instead of the piston 20 of the solenoid valve 10, and a main body part 237 is provided instead of the main body part 37 of the solenoid valve 10. The components that are identical to those of the first embodiment are designated with the same reference numerals and are not described in detail here. The main body part 237 of the second embodiment has a bushing 232 instead of the bushing 32. The piston 120 is also referred to as a valve element, and the bushing 232 is also referred to as a valve element receiving section. Fig. 9 represents an open valve position such as the Fig. 2 dar.

[0052] In the solenoid valve 210, the piston 120 does not have the first groove 21 and the second groove 22. Instead, a first groove 221 and a second groove 222 are formed in an inner wall surface of the bushing 232, that is, in a surface of the bushing 232 opposite the piston 120. The first groove 221 is a groove that extends axially from a Y-direction end of the inner wall surface of the bushing 232 opposite a side surface of the piston 120 to the X-direction side. The second groove 222 is an annular groove that is arranged to intersect with an X-direction end of the first groove 221 and extends circumferentially around the bushing 232. A region of the bushing 232, where the first groove 221 and the second groove 222 are provided, has a longer distance between the bushing 232, which serves as the valve element receiving section, and the piston 120 when compared with a remaining region of the bushing 232.

[0053] The configuration of the solenoid valve 210 of this embodiment, described above, has the first groove 221 and the second groove 221 provided in the bushing 232 and exhibits similarly advantageous effects as the first embodiment. Even if liquid water present in the gas supplied to the solenoid valve 210 enters a free space between the piston 120 and the bushing 232 and freezes, this configuration reduces the malfunction of the solenoid valve 210 caused by the freezing of the water. More precisely, the first groove 221 and the second groove 222 serve to retain the liquid water and thus prevent it from freezing.The presence of the second groove 222, which extends circumferentially, serves to channel the liquid water that penetrates the space between the piston 120 and the bushing 232 circumferentially, thereby preventing it from spreading axially. As a result, if the ingressing liquid water freezes, this configuration facilitates the removal of the piston 120's fixing caused by the freezing. The presence of the second groove 222, in addition to the first groove 221, makes it easier to discharge the liquid water that has accumulated in the first groove 221, thus improving the beneficial effect of reducing the malfunction of the solenoid valve 210 caused by the freezing of the liquid water.

[0054] The Fig. Figure 10 is a view showing a magnified section with the bushing 232 and the piston 120 in the Fig. 9 represents. A dashed line L3, which originates from the Fig. As can be seen in Figure 10, this designates a position that overlaps with one end on the side of the valve section 45 (Y-direction end) of the piston 120 in the horizontal direction in the open valve position. A dashed line L4, which extends from the Fig. As can be seen in Figure 10, the Y-end of the first groove 221 is designated as the position of a Y-direction end. According to the second embodiment, the first groove 221 is configured to extend from the Y-direction end of the inner wall surface of the bushing 232 opposite the side face of the piston 120 to the X-direction side. However, this configuration is not limiting, and a different configuration can be used. The first groove 221 can have any configuration, as long as it is configured to extend axially from a Y-direction side at a position that overlaps the end on the side of the valve section 45 of the piston 120 in the horizontal direction (position of the dashed line L3) with the X-direction side in the open valve position.This configuration allows liquid water accumulated in the second groove 222 to be discharged via the first groove 221 using the flow of hydrogen gas. To achieve the advantageous effect described above directly after a valve opening operation of the solenoid valve 210, the first groove 221 can be configured to extend axially from the Y-direction side, overlapping horizontally with the end on the side of the valve section 45 of the piston 120, even in the X-direction side, when the valve is closed.

[0055] Additionally, a term used in Fig. The dashed line L5 shown in Figure 10 indicates a position that overlaps with one end on the side of the valve section 45 of the second groove 222, which is provided in the bushing 232 in the horizontal direction. A dashed line L6 extending from the Fig. As can be seen in Figure 10, a position is designated that overlaps the center in the axial direction of the piston 120 in the horizontal direction in the open valve position. The positional ratio between the dashed line L5 and the dashed line L6 can be arbitrarily set, and the dashed line L5 can be placed on the side of the valve section 45 of the dashed line L6. More precisely, a Y-direction end of the second groove 222 can be placed on the side of the valve section 45 of the center in the axial direction of the piston 120 in the open valve position. When liquid water enters the space between the piston 120 and the bushing 232 from one end on the side of the valve section 45 of the piston 120, this configuration allows the entering liquid water to be introduced more immediately into the second groove 222.This improves the beneficial effect of reducing the problem of piston 120 becoming stuck, which is caused by the freezing of the liquid water.

[0056] According to the second embodiment, the first groove 221 is designed to be shallower than the second groove 222 (as shown in the Fig. 9 and Fig. 10 shows how the configuration of the first modification of the first embodiment, which is derived from the Fig. 7 is evident. However, this configuration is not limiting, and a different configuration can be used. For example, the first groove 221 and the second groove 222 can be configured to have identical depths, as in the configuration of the first embodiment, which is derived from the Fig. 6 is evident. In another example, the first groove 221 can be configured to be deeper than the second groove 222, as in the configuration of the second modification of the first embodiment, which is derived from the Fig. 8 is evident. C. Modifications*Modification 1

[0057] In the solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment described above, the second groove 22 or 222, which extends in the circumferential direction, is arranged to overlap with the X-direction end of the first groove 21 or 221, which extends in the axial direction. However, this configuration is not limiting, and a different configuration can be used. For example, the second groove can be arranged to intersect with the first groove at a position on the Y-direction side of the X-direction end of the first groove. This modified configuration also allows liquid water to be introduced in the circumferential direction and exhibits similarly advantageous effects.To ensure that the liquid water penetrating the space between the piston and the bushing is safely introduced in the circumferential direction, the second groove can overlap with the X-direction end of the first groove.

[0058] In the solenoid valve 10 of the first embodiment, the first groove 21 is configured to extend axially from the end on the side of the valve section 45 (Y-direction end) in the axial direction of the piston to the X-direction side. However, this configuration is not limiting, and a different configuration can be used. For example, the Y-direction end of the first groove 21 can be arranged to be located away from the Y-direction end of the piston 20. In the solenoid valve 210 of the second embodiment, the end on the side of the valve section 45 (Y-direction end) of the first groove 21 is arranged on the Y-direction side of the Y-direction end of the piston 120 in the open valve position. However, this configuration is not limiting, and a different configuration can be used.For example, the Y-direction end of the first groove 221 can be arranged on the X-direction side of the Y-direction end of the piston 120 in the open valve position.

[0059] As described above, the first groove and the second groove can have any configuration, as long as the second groove is arranged to intersect with the first groove at a position away from the Y-direction end of the first groove and to be extended in the circumferential direction. *Modification 2

[0060] In the solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment described above, the second groove 22 or 222 is configured as an annular groove that is continuous around the entire circumference of the piston 20 or around the entire circumference of the bushing 232. However, this configuration is not limiting, and a different configuration may be used. The second groove 22 or 222 may have any configuration, as long as the second groove 22 or 222 is arranged to intersect with the first groove 21 or 221 and to extend circumferentially over the width of the first groove 21 or 221. To ensure the efficiency of the second groove 22 or 222 in retaining liquid water, the circumferentially extended second groove 22 or 222 may have a greater length.More precisely, the length of the second groove 22 or 222, which extends in the circumferential direction, must not be less than one third of the length of the entire circumference of the piston 20 or the bushing 232, must not be less than half the length of the entire circumference, and must not be less than two thirds of the length of the entire circumference. *Modification 3

[0061] The solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment, described above, is provided with a single first groove 21 or 221, but can also be provided with several first grooves 21 or 221. The smaller number of first grooves 21 or 221 makes it easier to ensure the distance between the bushing 32 or 232 and the piston 20 or 120, thereby facilitating the formation of the magnetic path. Conversely, the larger number of first grooves 21 or 221 improves the efficiency of the water discharge from the second groove 22 or 222 via the first groove 21 or 221.In the configuration provided with one or more first grooves 21 or 221, increasing the thickness of the first groove 21 or 221, i.e., increasing the cross-sectional area in the horizontal direction of the first grooves 21 or 221, reduces the possibility of liquid water freezing in the first groove 21 or 221. Conversely, decreasing the thickness of the first groove 21 or 221 allows the surrounding liquid water to be drawn into the first groove 21 or 221 more quickly by capillary action. The configuration of the first groove can be adjusted to achieve a desired effect of reducing the potential problem caused by water freezing, according to the operating environment and conditions of the solenoid valve. *Modification 4

[0062] The solenoid valve 10 of the first embodiment is provided with a single second groove 22, but can also be provided with several second grooves.

[0063] The Fig. Figure 11 is a view showing the appearance of a piston 320 from an example of such a modification. The piston 320 can be used in place of the piston 20 in the solenoid valve 10. The piston 320 has a first groove 21 and a second groove 322 instead of the second groove 22. Like the second groove 22, the second groove 322 is arranged to intersect with the first groove 21 and to be extended in the circumferential direction. However, the second groove 322 is divided into several (4 in the example of the Fig.11) Subdivided grooves arranged to lie parallel to one another, unlike the second groove 22. Such a division of the second groove 322 allows the surrounding liquid water to be drawn into the second groove 322 more quickly by capillary action. The number of divisions of the second groove 322 and the thicknesses of each sub-groove are not particularly limited, but can be adjusted arbitrarily, taking into account the degree of reduction of any potential problems caused by water freezing and the complexity of the division process. Similarly, in the solenoid valve 210 of the second embodiment, the second groove 222 provided in the bushing 232 can be subdivided into several sub-grooves. *Modification 5

[0064] In the solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment described above, the bushing 32 or 232, which serves as the valve element receiving section, and the base section 33 are formed integrally as the main body part 37 or 237. However, the bushing and the base section may be formed separately. *Modification 6

[0065] In the solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment described above, the entire structure, including the coil 30, the main body part 37, the piston 20 or 120, the valve section 45, the yoke 34, the spring 31, and the stop 38, is located in the housing 36. However, this configuration is not limiting, and a different configuration can be used. The solenoid valve can have any configuration, as long as a part of this structure is located in the housing 36 and the flow path formed in the base section 33 is arranged to be connectable to the hydrogen tank and the fuel cell. *Modification 7

[0066] The solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment is configured as the directly driven solenoid valve, but may have a different configuration. For example, the present disclosure can be applied to a control solenoid valve. In this application, for example, a control valve may be a valve element, and an element provided for placing the control valve within it may be a valve element receiving section. In another example, a main valve that is opened by opening a control valve may be a valve element, and an element provided for placing the main valve within it may be a valve element receiving section.The valve element is not limited to the piston being opened directly by the excitation of the coil, but can be moved in the axial direction to open with the supply of electricity to the coil, like the main valve of the control solenoid valve. In this application, providing grooves similar to the first and second grooves described above in either the valve element or the valve element receiving section provides similar advantageous effects to those of the embodiments described above. *Modification 8

[0067] The solenoid valve 10 of the first embodiment or the solenoid valve 210 of the second embodiment is provided in the hydrogen gas flow path. However, this configuration is not limiting. The solenoid valve of the present disclosure can be provided in any gas flow path where the ingress of liquid water is likely to occur. This application also has a similarly advantageous effect of reducing a potential problem caused by the freezing of liquid water within the solenoid valve.

Claims

[1] Solenoid valve (10; 210) used in a gas flow path, with: a coil (30); a valve element receiving section (32; 232) which is placed inside the coil (30); a valve element (20; 20a; 20b; 120; 320) which is placed within the valve element receiving section (32; 232) and is configured to be moved in an axial direction with the supply of electricity to the coil (30); a valve section (45) which is configured to open and close the gas flow path accompanied by the movement of the valve element (20; 20a; 20b; 120; 320), wherein either a surface of the valve element (20; 20a; 20b; 120; 320) opposite the valve element receiving section (32; 232) or a surface of the valve element receiving section (32; 232) opposite the valve element (20; 20a; 20b; 120; 320) having a first groove (21, 221) extending in the axial direction, and a second groove (22, 222, 322) arranged to intersect with the first groove (21, 221) and to extend in a circumferential direction, and the first groove (21, 221) is formed, extending at least from the second groove (22, 222, 322) to one side of the valve section, wherein the first groove (21) and the second groove (22, 322) are formed in the valve element (20; 20a; 20b; 320), and the first groove (21) is formed to extend in the axial direction from a valve section-side end of the valve element (20; 20a; 20b; 320), and wherein the valve element (20; 20a; 20b; 320) is configured such that a length in the axial direction between the second groove (22, 322) and the valve section-side end of the valve element (20; 20a; 20b; 320) is shorter than a length in the axial direction between the second groove (22, 322) and an end on the opposite side of the valve element (20; 20a; 20b; 320) that is opposite the valve section side. [2] Solenoid valve (10) according to claim 1, further comprising: a magnetic path formation element (34) having a bottom surface section (39) that is placed on the valve section side of the coil (30) in the axial direction, and which forms part of a magnetic path in the bottom surface section (39) when electricity is supplied to the coil (30), wherein one end of the bottom surface section (39) is placed near the valve element receiving section (32) in a closed valve position on the valve section side of a valve section-side end of the second groove (22) of the valve section (45). [3] Solenoid valve (10; 210) according to claim 1 or 2, wherein an opposite side end of the first groove (21, 221), which is opposite the valve section side, is arranged to overlap with the second groove (22, 222, 322). [4] Solenoid valve (210) used in a gas flow path, comprising: a coil (30); a valve element receiving section (232) which is placed inside the coil (30); a valve element (120) which is placed within the valve element receiving section (232) and is configured to be moved in an axial direction with the supply of electricity to the coil (30); a valve section (45) which is configured to open and close the gas flow path accompanied by the movement of the valve element (120), wherein either a surface of the valve element (120) opposite the valve element receiving section (232) or a surface of the valve element receiving section (232) opposite the valve element (120) has a first groove (221) extending in the axial direction, and a second groove (222) arranged to intersect with the first groove (221) and to extend in a circumferential direction, and the first groove (221) is formed to extend at least from the second groove (222) to one side of the valve section, wherein the first groove (221) and the second groove (222) are formed in the valve element receiving section (232), and one end is arranged on the side of the valve section of the first groove (221) in an open valve position on the valve section side of one end of the side of the valve section of the valve element (120) of the valve section (45). [5] Solenoid valve (210) according to claim 4, wherein one end is arranged on the side of the valve section of the second groove (222) in the open valve position at the valve section side of a center in the axial direction of the valve element (120) of the valve section (45). [6] Solenoid valve (10; 210) according to claim 4 or 5, wherein an opposite side end of the first groove (221), which is opposite the valve section side, is arranged to overlap with the second groove (222).

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