Liquid infiltration prevention structure for fuel cell system

Abstract

This hydrogen supply device has: an inflow port (20) having an outer peripheral surface (23a); a fitted part (30) that is installed from above to cover the outer peripheral surface (23a) of the inflow port (20); and an annular seal member (22) that is installed in a recessed part (21), which is formed on the outer peripheral surface (23a) of the inflow port (20), to seal between the inflow port (20) and the fitted part (30). The fitted part (30) includes a covering part (31) that covers the recessed part (21) from an outer peripheral side, and an extension part (40) extending downward from the covering part (31). A first gap (50) is formed between an inner peripheral surface (45) of the extension part (40) and an outer peripheral surface (24a) of the inflow port (20), the first gap (50) communicating with an external space (52) located radially outside an outer peripheral surface (33) of the extension part (40).

Description

Liquid infiltration prevention structure for fuel cell system

[0001] The present disclosure relates to a structure for preventing liquid from entering a fuel cell system, and more particularly to a structure for preventing liquid from entering a sealed portion between two members.

[0002] Japanese Patent Application Laid-Open Publication No. 2024-39717 discloses a hydrogen supply device for a fuel cell system equipped with a solenoid valve in the hydrogen supply path. The upper part of the housing of the solenoid valve is provided with a protruding connector that is inserted into a recess in a passage member. The outer peripheral surface of this cylindrical connector is provided with a recess that extends around the entire circumference, and an annular seal member is placed in this recess. This seal member provides a sealed connection between the passage member and the housing of the solenoid valve.

[0003] The connection configuration between the passage member and the solenoid valve described in the above publication has an abutment portion between the passage member and the cylindrical portion closer to the outside than the sealed portion by the seal member. Because a minute gap actually exists at this abutment portion, if water enters from the outside along the surface of the passage member, the water is sucked in through the minute gap by capillary action. This may cause water to seep into the sealed portion by the seal member, potentially corroding the surrounding metal components. Therefore, it is desirable to provide a structure that prevents liquid from entering the sealed portion between the two components.

[0004] One embodiment of the liquid infiltration suppression structure for a fuel cell system includes a first member having an outer peripheral surface, a second member assembled from above to cover the outer peripheral surface of the first member, and an annular sealing member provided in a recess formed in the outer peripheral surface of the first member to seal between the first and second members. The second member has a covering portion that covers the recess from the outer peripheral side, and an extension portion that extends downward from the covering portion. A gap is formed between the extension portion and the outer peripheral surface of the first member, communicating with an external space located radially outward from the outer peripheral surface of the extension portion.

[0005] 8 is a schematic cross-sectional view showing a portion of a hydrogen supply device according to one embodiment; FIG. 10 is an enlarged view of a fitted portion and an inflow port; FIG. 11 is an enlarged view corresponding to FIG. 2 showing an inflow port according to another embodiment; FIG. 12 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment; FIG. 13 is an enlarged view corresponding to FIG. 2 showing a fitted portion as a comparative example; FIG. 14 is an enlarged view corresponding to FIG. 2 showing a through hole penetrating an extension portion; FIG. 15 is a view taken along arrow VII of the extension portion of FIG. 6; FIG. 16 is an enlarged view corresponding to FIG. 2 showing a through hole according to another embodiment; FIG. 17 is a view taken along arrow IX of the extension portion of FIG. 8; FIG. 18 is a view corresponding to FIG. 17 showing a fitted portion according to another embodiment; FIG. 19 is an enlarged view of the fitted portion and a solenoid valve shown in FIG. 10; FIG. 19 is an enlarged view corresponding to FIG. 2 showing an inflow port according to another embodiment; FIG. 2 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment; FIG. 2 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment; FIG. 2 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment;

[0006] <Hydrogen Supply Device> Various embodiments will be described below with reference to Figures 1 to 16. As shown in Figure 1, a fuel cell system 1 has a hydrogen supply device 2 that supplies hydrogen to a fuel cell (not shown). The hydrogen supply device 2 has an upstream member 3 that forms an upstream flow path 3a, a downstream member 4 that forms a downstream flow path 4a, and a solenoid valve 5 that is connected to communicate between the upstream member 3 and the downstream member 4. Hydrogen flowing through the hydrogen supply device 2 flows from the upstream flow path 3a through the solenoid valve 5 to the downstream flow path 4a. The solenoid valve 5 adjusts the pressure of the hydrogen that flows in from the upstream flow path 3a. As a result, the hydrogen is adjusted to an appropriate pressure and flows into the downstream flow path 4a.

[0007] <Solenoid Valve> As shown in FIG. 1 , the solenoid valve 5 has a generally cylindrical iron core 10 located in the center, an electromagnetic coil 13 disposed around the iron core 10, and a housing-like yoke 14 that surrounds the electromagnetic coil 13. The yoke 14 is made of metal and is press-fit into the iron core 10. The axis of the iron core 10 is oriented vertically. A valve element 15 that can slide vertically and a coil spring 16 that presses the valve element 15 upward are provided in the internal space 11 of the iron core 10. The valve element 15 is biased by the spring force of the coil spring 16 to close an inlet 17 of the internal space 11. When an electrical signal is input to the electromagnetic coil 13, the valve element 15 moves downward against the spring force of the coil spring 16, thereby opening the inlet 17 of the iron core 10. The amount of movement of the valve element 15 can be adjusted based on the electrical signal. This allows for control of the pressure reduction of hydrogen passing through the internal space 11.

[0008] <Inflow Port> A cylindrical inflow port 20 protrudes upward from the top surface 12 of the core section 10. The interior of the inflow port 20 is connected to the inlet 17 of the core section 10. The inflow port 20 has a smaller diameter than the core section 10. As shown in FIG. 2 , the inflow port 20 has a recess 21 formed on the outer circumferential surface 23a of its tip end 23, extending around the entire circumference. An annular seal member 22 is provided in the recess 21. The inflow port 20 has a tip end 23 in which the recess 21 is formed. The tip end 23 is radially smaller than the base end 24. Therefore, a step 25 is formed in the vertical center of the inflow port 20. This inflow port 20 is inserted into the fitted portion 30 of the upstream member 3 from below. In another embodiment, the inflow port does not have to have the step 25, as shown in FIG. 3 .

[0009] <Fitted Portion> As shown in FIG. 1 , the fitted portion 30 is a cylindrical portion that protrudes downward from the upstream member 3. The interior of the fitted portion 30 is in communication with the upstream flow path 3a. The inner diameter of the fitted portion 30 is formed to be approximately the same as or slightly larger than the outer diameter of the tip portion 23 of the inflow port 20. Therefore, when the inflow port 20 is inserted into the fitted portion 30, the fitted portion 30 covers the tip portion 23 of the inflow port 20 from the outer periphery. In addition, a seal member 22 seals between the fitted portion 30 and the inflow port 20. The upstream flow path 3a of the upstream member 3 and the internal space 11 of the iron core portion 10 are in communication with each other via the inflow port 20.

[0010] 2 , the fitted portion 30 has a cover portion 31 that covers the recess 21 of the inlet port 20 from the outer periphery, and an extension portion 40 that extends downward from the cover portion 31. The extension portion 40 extends in a cylindrical shape along the periphery of the solenoid valve 5. The extension portion 40 is made up of a first extension portion 41 that extends downward from the cover portion 31, and a second extension portion 44 that extends further downward than the first extension portion 41. The second extension portion 44 extends from the radially outer end of the first extension portion 41. The first extension portion 41 and the second extension portion 44 form a stepped shape that gradually descends as it extends radially outward.

[0011] <First Extension Portion> The first extension portion 41 has an inner circumferential surface 42 that extends downward along the covering surface 32 of the covering portion 31, and a lower surface 43 that extends radially outward from the lower end of the inner circumferential surface 42. The inner circumferential surface 42 has a chamfer 47 at the lower surface 43. The inner circumferential surface 42 faces the outer circumferential surface 23a of the tip portion 23 of the inflow port 20. The lower surface 43 partially abuts against the stepped portion 25 of the inflow port 20 (abutment portion 47). Note that the lower surface 43 does not necessarily have to abut against the stepped portion 25 of the inflow port 20.

[0012] <Second Extension Portion> The second extension portion 44 is formed to cover the outer peripheral surface 24a of the base end portion 24 of the inlet port 20 from the outer periphery side, with a gap therebetween. The second extension portion 44 has an inner periphery surface 45 extending downward from the lower surface 43 of the first extension portion 41 and a lower surface 46 extending radially outward from the lower end of the inner periphery surface 45. The outer periphery surface 33 of the fitted portion 30 extends downward to the lower surface 46 of the second extension portion 44. A first gap 50 is formed between the base end portion 24 of the inlet port 20 and the inner periphery surface 45, with a predetermined radial gap therebetween. The vertical length of the first gap 50 is determined by the vertical length of the second extension portion 44. The first gap 50 opens downward. The first gap 50 is also in communication with an external space 52 via a communication passage 51 formed between the lower surface 46 of the second extension portion 44 and the upper surface 12 of the core portion 10. The communication passage 51 connects the open lower end of the first gap 50 with the external space 52 .

[0013] <Gap of Second Extension Portion> The first gap 50 is formed to have a certain width and length to prevent capillary action when a liquid such as water enters. A comparative structure is shown in FIG. 5 . In this structure, the mated portion 130 has a contact portion 135 on its lower surface 134 that contacts the inlet port 120. However, the second extension portion 44 is not present, and therefore a space with a certain width and length like the first gap 50 is not formed between the mated portion 130 and the inlet port 120. In this comparative example, water droplets dripping from the outer peripheral surface 133 of the mated portion 130 run along the lower surface 134 and contact the contact portion 135. A minute gap actually exists between the surfaces of this contact portion 135. Therefore, water droplets that come into contact with the contact portion 135 penetrate deep into the contact portion 135 due to capillary action. The water droplets that have entered remain on the covering surface 132 of the covering portion 131 and in the recess 121. This can cause the fitted portion 130 and the inlet port 120 to corrode.

[0014] In contrast, in the hydrogen supply device 2 shown in Figures 1 to 3, the first gap 50 between the base end 24 of the inlet port 20 and the inner circumferential surface 45 of the second extension portion 44 is formed so as not to cause capillary action. That is, the first gap 50 has a sufficient width to prevent water droplets that have entered therein from being sucked upward, and a sufficient vertical length from the lower surface 46 of the second extension portion 44 to the seal member 22. This prevents water droplets from penetrating between the cover portion 31 and the seal member 22 or into the recess 21. Furthermore, the first gap 50 communicates with the external space 52 via the communication passage 51. This allows water droplets that have entered the first gap 50 to easily escape into the external space 52. This more appropriately prevents water droplets from penetrating into the recess 21, etc.

[0015] To summarize the above, the liquid infiltration suppression structure for a fuel cell system includes a first member (inlet port 20, solenoid valve 5) having an outer peripheral surface 23a, a second member (fitted portion 30) assembled from above to cover the outer peripheral surface 23a of the first member, and an annular sealing member 22 provided in a recess 21 formed in the outer peripheral surface 23a of the first member to seal between the first member and the second member. The second member has a covering portion 31 that covers the recess 21 from the outer periphery, and an extending portion 40 that extends downward beyond the covering portion 31. A first gap 50 is formed between the extending portion 40 and the outer peripheral surface 24a of the first member, and communicates with an external space 52 that is radially outward from the outer peripheral surface 33 of the extending portion 40.

[0016] With the above configuration, the first gap 50 is formed below the cover portion 31. This makes it difficult for liquids such as water to flow down the second member and enter the cover portion 31. Moreover, the first gap 50 communicates with the external space 52. Therefore, water that enters the first gap 50 is easily discharged without remaining there.

[0017] Furthermore, the first gap 50 has a certain width and / or length so as to prevent capillary action from occurring. With the above configuration, it is possible to prevent the liquid that has flowed into the first gap 50 from penetrating into the cover portion 31 due to capillary action.

[0018] The extension portion 40 has a stepped shape that gradually descends from the lower end of its inner circumferential surface (inner circumferential surface 42) toward the lower end of the outer circumferential surface 33 of the extension portion 40. This configuration can prevent liquid flowing downward along the outer circumferential surface 33 of the extension portion 40 from flowing radially inward. The stepped shape also makes it easier to form the first gap 50 between the inner circumferential surface (inner circumferential surface 45) of the extension portion 40 and the outer circumferential surface 24a of the first member.

[0019] <Tapered Extension Portion> In another embodiment, as shown in Fig. 4, the fitted portion 30 may have a tapered extension portion 60. Specifically, the extension portion 60 has a tapered surface 61 whose lower surface slopes obliquely downward radially outward. The tapered surface 61 extends from the lower end of the inner circumferential surface 62 to the lower end of the outer circumferential surface 33. Therefore, water droplets adhering to the tapered surface 61 flow radially outward. This makes it difficult for the water droplets to flow toward the inlet port 20. Furthermore, a first gap 50 is formed between the tapered surface 61 and the inlet port 20. This more appropriately prevents water droplets from penetrating the cover portion 31.

[0020] To summarize the above, the extension portion 60 has a tapered portion (tapered surface 61) that slopes obliquely downward from the lower end of its inner circumferential surface 62 toward the lower end of the outer circumferential surface 33 of the extension portion 60. With the above configuration, liquid that has flowed to the lower end of the outer circumferential surface 33 is less likely to flow toward the lower end of the inner circumferential surface 62. This makes it easier to prevent liquid from seeping into the cover portion 31.

[0021] <Extension Portion with Through Hole> In another embodiment, as shown in FIGS. 6 and 7 , the first gap 50 and the external space 52 may be connected to each other by a through hole 53 that penetrates the second extension portion 44 in the radial direction. This allows water that has entered the first gap 50 to easily escape, even when the lower surface 46 of the second extension portion 44 and the upper surface 12 of the core portion 10 are in contact with each other. This also makes it difficult for a pressure difference to occur between the first gap 50 and the external space 52. This prevents water that has entered the first gap 50 from rising. As shown in FIGS. 8 and 9 , the through hole 53 may be a slit-shaped opening. The through hole may be a slit-shaped opening that does not reach the lower surface 46, or may have any other shape. Multiple through holes may also be provided. The through hole 53 may be formed in the second extension portion 44 that does not contact the upper surface 12 of the core portion 10.

[0022] In summary, the first gap 50 is connected to the external space 52 by the through-hole 53 that radially penetrates the extension portion (second extension portion 44). With the above configuration, water droplets that have entered the first gap 50 can easily escape from the through-hole 53 to the external space 52.

[0023] <Extension Portion Covering the Yoke from the Outer Circumferential Side> In another embodiment, as shown in FIGS. 10 and 11 , the extension portion 80 of the fitted portion 30 may extend downward to a position covering the yoke 14. As shown in FIG. 11 , the yoke 14 has a protrusion 14b that protrudes upward from the inner circumferential end of its upper surface 14a. The protrusion 14b contacts the outer circumferential surface 10a of the core portion 10. The protrusion 14b protrudes cylindrically along the outer circumferential surface 10a. Meanwhile, the inner circumferential surface 85 of the second extension portion 84 is located radially outward of the protrusion 14b of the yoke 14. The second extension portion 84 extends downward beyond the upper end of the protrusion 14b and covers the outer circumferential surface 14c of the protrusion 14b from the outer circumferential side. As a result, a second gap 70 is formed between the inner circumferential surface 85 of the second extension portion 84 and the outer circumferential surface 14c of the protrusion 14b, with a predetermined radial gap therebetween.

[0024] The vertical length of the second gap 70 is determined by the vertical length of the second extension portion 84. The second extension portion 84 is also spaced apart from the upper surface 14a of the yoke 14. That is, a communication passage 71 is formed at a predetermined distance between the lower surface 86 of the second extension portion 84 and the upper surface 14a of the yoke 14. The second gap 70 communicates with the external space 52 via the communication passage 71.

[0025] Like the first gap 50, the second gap 70 has a width and / or length of at least a certain amount so that capillary action does not occur when a liquid such as water enters. This makes it possible to easily release water droplets that have entered the second gap 70 or the communicating passage 71 into the external space 52 without being sucked up above the protrusion 14b. This makes it possible to prevent water droplets from flowing into minute gaps that exist at the contact surface between the protrusion 14b and the outer circumferential surface 10a of the core portion 10 and penetrating into the interior of the yoke 14.

[0026] 11 , the outer peripheral surface 24a of the base end 24 of the inlet port 20 is located higher than the outer peripheral surface 10a of the core 10. The second extension 84 forms a first gap 50 between its inner peripheral surface 85 and the outer peripheral surface 24a. The first gap 50 is in communication with the second gap 70 and also in communication with the external space 52 via the communication passage 71.

[0027] An inner circumferential surface 82 of the first extending portion 81 has a chamfer 87 between it and a lower surface 83. The lower surface 83 of the first extending portion 81 is positioned so as not to come into contact with the stepped portion 25 of the inflow port 20. In another embodiment, the inflow port 20 does not have to have the stepped portion 25, as shown in FIG.

[0028] To summarize the above, the liquid infiltration suppression structure for a fuel cell system includes a third member (yoke 14) that contacts the outer peripheral surface 10a of the first member (iron core 10, solenoid valve 5) below the recess 21. The extension 80 covers the third member from the outer peripheral side so as to form a second gap 70 between its inner peripheral surface 85 and the outer peripheral surface 14c of the third member. The second gap 70 has a certain width or length to prevent capillary action and communicates with the external space 52. Therefore, liquid such as water that has entered the second gap 70 can be prevented from being sucked up to the contact surface between the first member and the third member by capillary action. This prevents liquid from infiltrating into the contact surface between the first member and the third member.

[0029] The third member also has a protrusion 14b that protrudes upward from its upper surface. The second gap 70 is formed between the outer peripheral surface 14c of the protrusion 14b and the inner peripheral surface 85 of the extension 80. Therefore, the second gap 70 can be formed with a simple configuration in which the extension 80 covers the protrusion 14b from the outer peripheral side. For example, even if the third member is configured to protrude significantly outward in the radial direction, the extension 80 does not need to cover the entire third member from the outer peripheral side, and the infiltration suppression structure can be formed compactly.

[0030] 13 , the fitted portion 30 may have an extending portion 90 that extends downward in a tapered manner from the covering portion 31. The extending portion 90 has a tapered surface 91 that slopes downward as it extends radially outward. The extending portion 90 extends downward below the upper end of the protrusion 14 b and radially outward so that the tapered surface 91 does not interfere with the inlet port 20, the iron core 10, or the yoke 14.

[0031] As a result, the tapered surface 91 covers the inlet port 20 and the protrusion 14b from the outer periphery with a gap therebetween. That is, a first gap 50 is formed between the tapered surface 91 and the inlet port 20. A second gap 70 is formed between the tapered surface 91 and the protrusion 14b.

[0032] 14 , the inner surface of the extension portion 100 of the fitted portion 30 may be multi-stepped along the outer shape of the solenoid valve 5. The extension portion 100 has a first extension portion 101 extending downward from the cover portion 31. The first extension portion 101 extends such that a gap is formed between its lower surface 102 and the stepped portion 25 of the inlet port 20.

[0033] The second extending portion 103 extends downward from the lower part of the first extending portion 101 so as to avoid the base end portion 24. The second extending portion 103 extends along the base end portion 24 of the inlet port 20. As a result, the second extending portion 103 covers the base end portion 24 of the inlet port 20 from the outer periphery side. A first gap 50 is formed between an inner circumferential surface 104 of the second extending portion 103 and an outer circumferential surface 24a of the base end portion 24. The second extending portion 103 also extends so that a gap is formed between its lower surface 105 and the upper surface 12 of the core portion 10.

[0034] A third extension portion 106 extends downward from the lower part of the second extension portion 103 so as to avoid the iron core portion 10 and the protruding portion 14b of the yoke 14. The third extension portion 106 extends along the protruding portion 14b of the yoke 14. As a result, the third extension portion 106 covers the outer peripheral surface 14c of the protruding portion 14b from the outer periphery side. A second gap 70 is formed between an inner peripheral surface 107 of the third extension portion 106 and the outer peripheral surface 14c of the protruding portion 14b. In addition, a lower surface 108 of the third extension portion 106 forms a communication path 71 with the upper surface 14a of the yoke 14.

[0035] 15 and 16 , the second gap 70 may be connected to the external space 52 by a through hole 72 that radially penetrates the second extension portion 84. In this case, the lower surface 86 of the second extension portion 84 may abut against the upper surface 14 a of the yoke 14.

[0036] The through hole 72 may be, for example, a circular opening like the through hole 53 shown in FIG. 7 , or a slit-like opening that reaches the lower surface 86 like the through hole 53 shown in FIG. 9 . The through hole 72 allows water that has entered the second gap 70 to easily escape to the external space 52. Note that the through hole 72 is not limited to the shape shown in the figure and may have any other shape. Furthermore, the second extension portion 84 may have one through hole 72 or multiple through holes 72 arranged in the circumferential direction. As shown in FIG. 16 , the second extension portion 84 may have both a communication passage 71 and a through hole 72.

[0037] Other Embodiments In other embodiments, the features described above can be applied to various seal structures consisting of a first member and a second member, in addition to the hydrogen supply device. The first member may be a columnar member instead of a cylindrical member. The second member may be a flange-shaped member.

[0038] In another embodiment, the step shape of the extension portion may have two or more steps, and the tapered surface may extend in a curved shape rather than in a straight line.

[0039] In another embodiment, the third member may be a resin coating that covers the yoke 14, and the protrusion may be a part of this resin coating.

[0040] Although various embodiments have been described above, the present disclosure is not limited to these embodiments, and various other modifications, substitutions, improvements, and the like are possible for those skilled in the art.

Claims

1. A liquid infiltration suppression structure for a fuel cell system, comprising: a first member having an outer peripheral surface; a second member assembled from above so as to cover the outer peripheral surface of the first member; and an annular sealing member provided in a recess formed in the outer peripheral surface of the first member so as to seal between the first member and the second member, wherein the second member has a covering portion that covers the recess from the outer periphery and an extension portion that extends downward beyond the covering portion, and a first gap is formed between the extension portion and the outer peripheral surface of the first member, the first gap communicating with an external space that is radially outward from the outer peripheral surface of the extension portion.

2. A liquid infiltration suppression structure according to claim 1, wherein the first gap has a certain width or length so as to prevent capillary action from occurring.

3. A liquid infiltration suppression structure according to claim 1 or claim 2, wherein the extension portion has a stepped shape that gradually decreases from the lower end of the inner circumferential surface of the extension portion to the lower end of the outer circumferential surface of the extension portion.

4. A liquid infiltration suppression structure according to any one of claims 1 to 3, wherein the extension portion has a tapered portion that slopes obliquely downward from the lower end of the inner circumferential surface of the extension portion toward the lower end of the outer circumferential surface of the extension portion.

5. A liquid infiltration suppression structure according to any one of claims 1 to 4, wherein the first gap is in communication with the external space via a through hole that penetrates the extension portion in the radial direction.

6. A liquid infiltration suppression structure according to any one of claims 1 to 5, comprising a third member that contacts the outer peripheral surface of the first member below the recess, the extension portion being fitted over the third member from the outer peripheral side so as to form a second gap between the inner peripheral surface of the extension portion and the outer peripheral surface of the third member, and the second gap communicating with the external space.

7. A liquid infiltration suppression structure according to claim 6, wherein the second gap has a certain width or length so as to prevent capillary action from occurring.

8. A liquid infiltration suppression structure according to claim 6 or 7, wherein the third member has a convex portion that protrudes upward from the top surface of the third member, and the second gap is formed between the outer peripheral surface of the convex portion and the inner peripheral surface of the extension portion.

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