Liquid intrusion suppressing structure in fuel cell system

Abstract

To provide a structure for restraining infiltration of liquid into a seal place between two members.SOLUTION: This hydrogen supplying device has an inflow port 20 having an outer peripheral surface 23a, a fitted part 30 assembled from above so as to cover the outer peripheral surface 23a of the inflow port 20, and an annular seal member 22 arranged in a recessed part 21 formed on the outer peripheral surface 23a of the inflow port 20 so as to seal between the inflow port 20 and the fitted part 30. The fitted portion 30 includes a covering portion 31 that covers the recess 21 from the outer peripheral side, and an extending portion 40 that extends downward from the covering portion 31. A first gap 50 is formed between the inner peripheral surface 45 of the extending part 40 and the 24a of the outer peripheral surface of the inflow port 20, the first gap 50 communicating with an external space 52 located radially outward of the outer peripheral surface 33 of the extending part 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[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. [Background technology]

[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 passage. A protruding connector is provided on the top of the housing of the solenoid valve, and is connected by being inserted into a recess in a passage member. A recess extending around the entire circumference is provided on the outer circumferential surface of this cylindrical connector, and an annular seal member is disposed in the recess. This seal member provides a sealed connection between the passage member and the housing of the solenoid valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-39717 Summary of the Invention [Problem to be solved by the invention]

[0004] 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. [Means for solving the problem]

[0005] 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 extending portion that extends downward from the covering portion. A gap is formed between the extending 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 extending portion. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic cross-sectional view showing a part of a hydrogen supply device according to one embodiment. [Figure 2] FIG. 10 is an enlarged view of the fitted portion and the inlet port. [Figure 3] 3 is an enlarged view corresponding to FIG. 2 showing an inflow port according to another embodiment. [Figure 4] 10 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment. [Figure 5] 3 is an enlarged view corresponding to FIG. 2 showing a fitted portion as a comparative example. [Figure 6] 3 is an enlarged view corresponding to FIG. 2, showing a through-hole penetrating the extension portion. FIG. [Figure 7] 7 is a view of the extension portion of FIG. 6 taken along arrow VII. [Figure 8] 10 is an enlarged view corresponding to FIG. 2 showing a through hole according to another embodiment. [Figure 9] 9 is a view of the extension portion of FIG. 8 taken along the arrow IX. [Figure 10] 10 is a view corresponding to FIG. 1 showing a fitted portion according to another embodiment. FIG. [Figure 11] FIG. 11 is an enlarged view of the fitted portion and the solenoid valve shown in FIG. [Figure 12] 3 is an enlarged view corresponding to FIG. 2 showing an inflow port according to another embodiment. [Figure 13] 10 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment. [Figure 14]10 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment. [Figure 15] 10 is an enlarged view corresponding to FIG. 2 showing a fitted portion according to another embodiment. [Figure 16] 10 is an enlarged view corresponding to FIG. 2 showing a through hole according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] <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 has flowed 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.

[0008] <Solenoid valve> As shown in FIG. 1 , the solenoid valve 5 has a generally cylindrical core 10 located in the center, an electromagnetic coil 13 disposed around the core 10, and a housing-like yoke 14 surrounding the electromagnetic coil 13. The yoke 14 is made of metal and is press-fit into the core 10. The axis of the 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 core 10. The spring force of the coil spring 16 biases the valve element 15 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 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.

[0009] <Inlet port> A cylindrical inlet port 20 protrudes upward from the top surface 12 of the core portion 10. The interior of the inlet port 20 is connected to the inlet 17 of the core portion 10. The inlet port 20 has a smaller diameter than the core portion 10. As shown in FIG. 2, the inlet port 20 has a recess 21 formed on the outer peripheral surface 23a of its tip portion 23, extending around the entire circumference. An annular seal member 22 is provided in the recess 21. The inlet port 20 is formed so that the tip portion 23, where the recess 21 is formed, is radially smaller than the base end portion 24. Therefore, a step 25 is formed in the vertical center of the inlet port 20. This inlet port 20 is inserted into the fitted portion 30 of the upstream member 3 from below. In another embodiment, the inlet port does not have to have the step 25, as shown in FIG. 3.

[0010] <Mating part> 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 sealing 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.

[0011] <Extension part> As shown in FIG. 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 moves radially outward.

[0012] <1st extension> The first extending 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. A chamfer is formed between the inner circumferential surface 42 and 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.

[0013] <Second extension part> 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 between them. 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 .

[0014] <Gap in the second extension> The first gap 50 is formed with a certain width and length to prevent capillary action when a liquid such as water enters. FIG. 5 shows a comparative structure. In this structure, the fitted 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 fitted portion 130 and the inlet port 120. In this comparative example, water droplets dripping from the outer peripheral surface 133 of the fitted portion 130 run along the lower surface 134 and contact the contact portion 135. This contact portion 135 actually has a small gap between its surfaces. 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 penetrate remain within the covering surface 132 of the covering portion 131 and the recess 121. This may cause the fitted portion 130 and the inlet port 120 to corrode.

[0015] In contrast, in the hydrogen supply device 2 shown in FIGS. 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 entering 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 entering the recess 21, etc.

[0016] To summarize the above, the liquid infiltration suppression structure in 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 so as 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 so as 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 located radially outward from the outer peripheral surface 33 of the extending portion 40.

[0017] 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.

[0018] Furthermore, the first gap 50 has a certain width 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 covering portion 31 due to capillary action.

[0019] 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 makes it possible to 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.

[0020] <Tapered extension> In another embodiment, as shown in FIG. 4 , the fitted portion 30 may have a tapered extending portion 60. Specifically, the extending portion 60 has a lower surface that forms a tapered surface 61 that 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 entering the covering portion 31.

[0021] In summary, 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.

[0022] <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 slit-shaped. The through-hole may be slit-shaped and 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.

[0023] In summary, the first gap 50 is connected to the external space 52 by the through-hole 53 that penetrates the extension portion (second extension portion 44) in the radial direction. With the above configuration, water droplets that have entered the inside of the first gap 50 can be easily released from the through-hole 53 to the external space 52.

[0024] <Extension that covers the outer periphery of the yoke> In another embodiment, as shown in FIGS. 10 and 11 , the extension 80 of the fitted portion 30 may extend downward to a position that covers the yoke 14. As shown in FIG. 11 , the yoke 14 has a protrusion 14b that protrudes upward from the inner peripheral end of its upper surface 14a. The protrusion 14b contacts the outer peripheral surface 10a of the core portion 10. The protrusion 14b protrudes in a cylindrical shape along the outer peripheral surface 10a. Meanwhile, the inner peripheral surface 85 of the second extension 84 is located radially outward from the protrusion 14b of the first extension 81. The second extension 84 extends further downward than the upper end of the protrusion 14b and covers the outer peripheral surface 14c of the protrusion 14b from the outer peripheral side. As a result, a second gap 70 is formed between the inner peripheral surface 85 of the second extension 84 and the outer peripheral surface 14c of the protrusion 14b, with a predetermined radial gap therebetween.

[0025] The vertical length of the second gap 70 is determined by the vertical length of the second extending portion 84. The second extending portion 84 is suspended above 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 extending 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.

[0026] Like the first gap 50, the second gap 70 has a certain width and length to prevent capillary action from occurring 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 the minute gaps that exist at the contact surface between the protrusion 14b and the outer peripheral surface 10a of the core portion 10 and penetrating into the interior of the yoke 14.

[0027] 11 , the outer peripheral surface 24a of the base end portion 24 of the inlet port 20 is located higher than the outer peripheral surface 10a of the core portion 10. The second extension portion 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 is also in communication with the external space 52 via a communication passage 71.

[0028] A chamfer is formed between the inner circumferential surface 82 and the lower surface 83 of the first extending portion 81. The lower surface 83 of the first extending portion 81 is located 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.

[0029] To summarize the above, the liquid infiltration suppression structure in a fuel cell system has 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.

[0030] The third member also has a protrusion 14b that protrudes upward from its top 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.

[0031] <Tapered extension> 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 14b 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.

[0032] As a result, the tapered surface 91 covers the inflow port 20 and the protrusion 14b from the outer circumferential side with a gap therebetween. That is, a first gap 50 is formed between the tapered surface 91 and the inflow port 20. A second gap 70 is formed between the tapered surface 91 and the protrusion 14b.

[0033] <Multi-stage extension> 14 , the inside 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 lower surface 102 thereof is spaced apart from the stepped portion 25 of the inlet port 20.

[0034] A 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. In addition, the second extending portion 103 extends so that a lower surface 105 thereof leaves a gap between it and the upper surface 12 of the core portion 10.

[0035] 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. A lower surface 108 of the third extension portion 106 forms a communication path 71 with the upper surface 14a of the yoke 14.

[0036] <Extending portion with through-hole> 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 14a of the yoke 14.

[0037] The through-hole 72 may be, for example, a circular opening like the through-hole 53 shown in FIG. 7 , or a slit-shaped opening that reaches the underside 86 like the through-hole 53 shown in FIG. 9 . The through-hole 72 makes it easier for water that has entered the second gap 70 to 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. The through-hole 72 may also be a plurality of through-holes 72 arranged in the circumferential direction. The second extension portion 84 may have both the communication passage 71 and the through-hole 72.

[0038] <Other embodiments> As another embodiment, 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.

[0039] 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.

[0040] 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.

[0041] 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. [Explanation of symbols]

[0042] 1. Fuel cell system 2. Hydrogen supply device 3 Upstream member 3a Upstream flow path 4 Downstream member 4a Downstream flow path 5. Solenoid valve (first component) 10 Iron core (first member) 10a Outer surface 11 Interior Space 12 Top side 13 Electromagnetic Coil 14 Yoke (third member) 14a Top side 14b Convex part 14c Outer surface 15 Valve body 16 Coil spring 17 Inlet 20 inlet port (first member) 21 Recess 22 Sealing material 23 Tip 23a Outer surface 24 Proximal end 24a Outer surface 25 Step 30 fitted portion (second member) 31 Cover 32 Covering surface 33 Outer surface 40 Extension 41 1st extension part 42 Inner surface 43 Bottom surface 44 Second extension part 45 Inner surface 46 Bottom side 47 Contact part 50 First Gap 51 Communication path 52 Exterior Space 53 Through hole 60 Extension 61 Tapered surface (tapered part) 62 Inner surface 70 Second Gap 71 Communication path 72 Through hole 80 Extension 81 1st extension part 82 Inner surface 83 Bottom surface 84 Second extension part 85 Inner surface 86 Bottom side 90 Extension part 91 Tapered surface 100 Extension 101 1st extension part 102 Bottom surface 103 Second extension part 104 Inner surface 105 Bottom surface 106 Third extension part 107 Inner surface 108 Bottom surface 120 inlet port 121 recess 122 sealing material 130 mating part 131 Cover 132 Covering surface 133 Outer surface 134 Bottom surface 135 Contact part

Claims

1. A liquid intrusion prevention structure in a fuel cell system, a first member having an outer circumferential surface; a second member attached from above to cover the outer peripheral surface of the first member; an annular sealing member provided in a recess formed in an outer peripheral surface of the first member so as to seal between the first member and the second member; the second member has a covering portion that covers the recess from the outer periphery side and an extending portion that extends downward from the covering portion, A liquid infiltration suppression structure in which 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 located radially outside the outer peripheral surface of the extension portion.

2. The liquid intrusion suppression structure according to claim 1, The first gap has a certain width or length to prevent capillary action from occurring, and is a liquid infiltration prevention structure.

3. The liquid infiltration suppression structure according to claim 1 or 2, The extension portion has a stepped shape that gradually decreases from the lower end of its inner circumferential surface toward the lower end of its outer circumferential surface, thereby preventing liquid from seeping in.

4. The liquid infiltration suppression structure according to claim 1 or 2, The extension portion has a tapered portion that slopes obliquely downward from the lower end of its inner circumferential surface toward the lower end of its outer circumferential surface, thereby preventing liquid from seeping in.

5. The liquid infiltration suppression structure according to claim 1 or 2, The first gap is a liquid infiltration prevention structure that communicates with the external space via a through hole that penetrates the extension portion in the radial direction.

6. The liquid intrusion suppression structure according to claim 1, a third member that contacts the outer circumferential surface of the first member below the recess; the extension portion is fitted over the third member from an outer circumferential side so as to form a second gap between an inner circumferential surface of the extension portion and an outer circumferential surface of the third member, The second gap is a structure that prevents liquid from entering and communicates with the external space.

7. The liquid infiltration suppression structure according to claim 6, The second gap has a certain width or length to prevent capillary action from occurring, and is a liquid infiltration prevention structure.

8. The liquid infiltration suppression structure according to claim 6 or 7, the third member has a protrusion protruding upward from its upper surface, A liquid infiltration suppression structure in which the second gap is formed between the outer peripheral surface of the convex portion and the inner peripheral surface of the extension portion.

Images