JPH09330781A - Plug cap air extractor structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air extractor structure of a plug cap effectively preventing water infiltration against a lower part in a plug hole. SOLUTION: A plug cap unit 14 is provided with a partition sealing wall part 22 for vertically partitioning an inside of a plug hole 13 between an upper side plug hole part 13a and a lower side plug hole part 13b. A rain cover 15 is provided with an outside communication pore 26 so as to communicate with an inside of the upper side plug hole part 13a and the outside air. A partition sealing wall part 22 is provided with an inside communication pore 25 so as to communicate with an inside of a lower side plug hole part 13a and an inside of an upper side plug hole part 13a. The outside communication pore 26 and the inside communication pore 25 are arranged at a position at which they are dislocated each other against an axial direction of the plug hole 13. An opening end 25a on a side of the upper side plug hole part 13a of the inside communication pore 25 is arranged at a top position inside the upper side plug hole part 13a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bleeding structure of a plug cap used for an ignition plug of an internal combustion engine of an automobile or the like.

[0002]

2. Description of the Related Art For example, as an air vent structure of this type,
As shown in FIGS. 4 and 5, the plug cap 1 is provided with a plug cap body 2 and a rain cover 3, and is inserted into a plug hole 5 formed in the engine head 4 and mounted on the engine side. In addition, the ignition cable 8 is connected via the terminal fitting 7, and the opening edge of the plug hole 5 is closed by the rain cover 3.

Further, the rain cover 3 is formed with an air vent hole 9 for communicating the inside of the plug hole 5 with the outside air so as to eliminate the pressure difference when the air in the plug hole 5 is expanded or contracted. Has been done. That is, when the pressure in the air in the plug hole 5 is increased when the plug cap 1 is attached to the plug hole 5 on the engine side or when the temperature of the engine is raised, the air inside the plug hole 5 can escape to the outside through the air vent hole 9. There is an advantage that the plug cap 1 can be prevented from popping out due to an increase in the internal pressure in the plug hole 5.

On the other hand, if the vicinity of the plug hole 5, that is, the vicinity of the rain cover 3 is exposed to water, water may enter the plug hole 5 through the air vent hole 9 and deteriorate the electrical insulation.

Therefore, in order to prevent water from entering the inside of the plug hole 5 through the air vent hole 9, as shown in an enlarged view of FIG. 5, a structure in which the outside air side portion of the air vent hole 9 has a smaller diameter, A structure is adopted in which a protruding portion 10 is formed in a protruding shape corresponding to a position above the outside air side opening end of the air vent hole 9 so that the air vent hole 9 portion is not directly exposed to water.

For example, it is as disclosed in Japanese Utility Model Laid-Open No. 7-25597.

[0007]

However, according to the above conventional air vent structure, as shown in FIG. 4, when the engine is exposed to water and water enters through the air vent hole 9, the spark plug 6 is directly attached. There is a problem that it penetrates into the lower part of the plug hole 5 provided.

Further, when the engine is hot and is exposed to water, the expanding air in the plug hole 5 is rapidly cooled and contracts, and the water adhering to the outside in the vicinity of the air vent hole 9 is vented. Since it is easily sucked through the hole 9, water directly penetrates into the lower part of the plug hole 5, and there is a problem that sufficient waterproofness cannot be ensured.

Therefore, an object of the present invention is to provide an air bleeding structure for a plug cap that effectively prevents water from entering the lower portion inside the plug hole.

[0010]

A technical means for solving the above-mentioned problems is to provide a cylindrical plug cap body which can be inserted into and removed from a plug hole formed in an engine head, and an upper end of the plug cap body. And a rain cover that closes an opening edge portion of the plug hole, and an air vent portion that communicates the inside of the plug hole with the outside air is provided. , A partition seal wall portion partitioning the inside of the plug hole into an upper upper plug hole portion and a lower lower plug hole portion, and the air bleeding portion is provided to communicate the inside of the upper plug hole portion with the outside air. The partition seal wall for communicating the outside communication hole formed in the cover with the inside of the lower plug hole portion and the inside of the upper plug hole portion. An inner communication hole formed in the inner communication hole, the outer communication hole and the inner communication hole being arranged at positions displaced from each other with respect to the axial direction of the plug hole, and the upper plug hole of the inner communication hole. The open end on the part side is located at an upper position in the upper plug hole part.

Further, the partition seal wall portion is mounted on a flange portion integrally provided on the outer periphery of the plug cap main body in the axial center direction so as to project, and a circumferential groove formed on the outer periphery of the flange portion. Also, a structure may be used in which the inner communication hole is formed in the flange portion, and the ring seal ring is in close contact with the inner peripheral surface of the plug hole.

Further, a structure may be adopted in which an opening end of the outer communication hole on the upper plug hole portion side is arranged at a lower position in the upper plug hole portion.

Further, the partition seal wall portion may be provided so that the upper plug hole portion is located above the position of the terminal fitting mounted in the plug cap body.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 11 is a plug cap for mounting an ignition plug formed on the engine head 12 side as in the conventional case. From a cylindrical plug cap body 14 formed of an insulating material such as a resin that can be inserted into and removed from the plug hole 13, and an elastic material such as rubber into which the upper end of the plug cap body 14 is fitted. And a lower end portion side of the plug cap body 14 is inserted into the plug hole 13, and the ignition cable 17 is connected to the ignition plug mounted on the engine side via the terminal fitting 16. At this time, the upper opening edge portion 18 of the plug hole 13 is configured to be closed by the rain cover 15.

A disk-shaped flange portion 19 having an appropriate thickness is formed integrally with the plug cap body 14 at an axially middle portion, that is, the outer periphery at the upper position, and the flange portion 19 has an appropriate thickness. An annular peripheral groove 20 is formed on the outer peripheral surface of the portion 19 along the circumferential direction.

Then, when the plug cap body 14 is inserted into the plug hole 13 with the O-ring 21 as a seal ring mounted in the circumferential groove 20, the O-ring 21 elastically deforms to cause the plug hole. The inner peripheral surface of the plug 13 is closely attached to the inner peripheral surface of the plug hole 13, and the inside of the plug hole 13 is partitioned into upper and lower chambers of an upper upper plug hole portion 13a and a lower lower plug hole portion 13b in an airtight manner.

Here, the flange portion 19 and the O-ring 2 are provided.
1 forms a partition seal wall portion 22 that partitions the inside of the plug hole 13 into upper and lower parts. At this time, the upper plug hole portion 13 a partitioned by the partition seal wall portion 22 is configured to be located above the position of the terminal fitting 16 mounted in the plug cap body 14.

Further, the rain cover 15 is provided on one side of the outer peripheral surface of the plug cap body 14 from the upper surface side of the flange portion 19.
The ridge portion 23 reaching near the lower surface of the plug cap body 1
4 is integrally provided along the axial center direction of 4, and the protrusion 23 and the flange 19 are provided so as to communicate the inside of the upper plug hole portion 13a and the inside of the lower plug hole portion 13b.
An inner communication hole 25 is formed in a penetrating manner along the axial direction of the plug cap body 14.

Therefore, as shown in FIG. 1, when the plug cap 11 is mounted, the opening end 25a of the inner communication hole 25 on the upper plug hole portion 13a side is arranged at the upper position in the upper plug hole portion 13a. It is said to have a structure.

Further, the rain cover 15 is formed with an outer communication hole 26 for communicating the inside of the upper plug hole portion 13a with the outside air outside the engine. As shown in FIG. The outer communication hole 26 and the inner communication hole 25 are arranged at positions displaced from each other with respect to the axial direction of the plug cap body 14 with the rain cover 15 attached to the portion.

The outer communication hole 26 and the inner communication hole 25 constitute an air vent for communicating the inside of the plug hole 13 with the outside air.

Further, the open end 2 of the outside communication hole 26 on the outside air side.
A protruding eaves portion 28 is formed above 6a in order to prevent water from being exposed, as in the conventional case.

The first embodiment is configured as described above, and even when the rain cover 15 is exposed to water and water enters the plug hole 13 through the outer communication hole 26, the inside of the plug hole 13 is prevented. Is airtightly divided into upper and lower upper plug hole portions 13a and lower plug hole portions 13b by the partition seal wall portion 22, so that the invading water is blocked by the partition seal wall portion 22 and the rain cover 15 Since the structure has a double sealing function of the partition wall portion 22 and the partition sealing wall portion 22, the waterproof property can be improved, and water can be effectively prevented from directly entering the lower part in the plug hole 13 to which the ignition plug is attached. .

Further, at this time, since the opening end 25a of the inner communication hole 25 on the upper plug hole portion 13a side is arranged at the upper position in the upper plug hole portion 13a, air is supplied to the inner communication hole 25 and the upper plug hole portion 13a. Ventilation is performed without any trouble through the portion 13a and the outer communication hole 26.

Further, the water accumulated in the upper plug hole portion 13a is discharged to the outside through the outer communication hole 26 when the temperature of the engine rises again and evaporates.

Further, since the upper plug hole portion 13a partitioned by the partition seal wall portion 22 is configured to be located above the position of the terminal fitting 16 mounted in the plug cap body 14, the upper plug hole portion 13a is configured to be located above. Plug hole 13
Good electrical insulation can be ensured even when water is accumulated in a.

It is more preferable to secure the volume of the upper plug hole portion 13a to be larger than the contraction amount when the air in the plug hole 13 is rapidly cooled from the high temperature state in order to prevent the intrusion of water.

FIG. 2 and FIG. 3 show the second embodiment, which is configured almost the same as the first embodiment. Therefore, the same components are designated by the same reference numerals and the description thereof is omitted.

That is, in the second embodiment, the ventilation guide portion 29 reaching the vicinity of the upper surface of the flange portion 19 on the lower surface side of the outer communication hole 26 portion of the rain cover 15.
Is integrally provided in a downward protruding shape, and the outer communication hole 2
The opening end 26b of the No. 6 on the upper plug hole portion 13a side is arranged at a lower position in the upper plug hole portion 13a.

Therefore, not only the same effects as those of the first embodiment are achieved, but also when water is accumulated in the upper plug hole portion 13a, if the engine is warmed up again,
As the air in the plug hole 13 expands, the water that has accumulated in the upper plug hole portion 13a is first discharged to the outside through the outer communication hole 26, so that the effect of water intrusion can be eliminated more efficiently. it can.

In the first and second embodiments, the inner communicating hole 25 and the outer communicating hole 26 are projected so that they are displaced from each other in the axial direction of the plug cap body 14. The plug cap main body has a positioning structure formed by a strip and a fitting groove into which the projection is fitted, and a detent mechanism that prevents the plug cap body 14 and the rain cover 15 from rotating relative to each other around the axis of the plug cap body 14. It may be provided appropriately between the 14 and the rain cover 15.

Further, the partition seal wall portion 22 having the same structure as the above.
May be provided on the rain cover 15.

[0033]

As described above, according to the air vent structure of the plug cap of the present invention, the partition seal wall portion for partitioning the inside of the plug hole into the upper upper plug hole portion and the lower lower plug hole portion is provided above and below. The air vent includes an outer communication hole formed in the rain cover for communicating the inside of the upper plug hole with the outside air, and the partition seal wall for communicating the inside of the lower plug hole with the inside of the upper plug hole. An inner communication hole formed in the inner hole, and the outer communication hole and the inner communication hole are arranged at positions displaced from each other with respect to the axial direction of the plug hole, and the upper plug of the inner communication hole is provided. Even if water enters the plug hole through the outer communication hole, the opening end on the hole side is located at the upper position in the upper plug hole. The inside of the plug hole is divided into the upper and lower plug hole parts and the lower plug hole part by the partition seal wall part, so the invading water is blocked by the partition seal wall part and has a double sealing function here. This structure has an advantage that the waterproof property can be improved and water can be effectively prevented from directly entering the lower part inside the plug hole where the spark plug is attached.

Further, since the opening end of the inner communication hole on the upper plug hole portion side is located at the upper position in the upper plug hole portion, there is no problem in ventilation through the inner communication hole, the upper plug hole portion and the outer communication hole. There is an advantage that the function can be exhibited.

Further, in the structure in which the opening end of the outer communication hole on the upper plug hole portion side is arranged at the lower position in the upper plug hole portion, when water is accumulated in the upper plug hole portion, When the engine warms up again, the water that has accumulated is first discharged to the outside through the outer communication hole as the air in the plug hole expands.
There is an advantage that the effect of water intrusion can be eliminated more efficiently.

Further, if the partition seal wall portion is provided so that the upper plug hole portion is located above the position of the terminal fitting mounted in the plug cap body, the upper side is provided. There is an advantage that good electrical insulation can be ensured even when water is accumulated in the plug hole portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing a second embodiment of the present invention.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view showing a conventional example.

FIG. 5 is an enlarged view of the relevant part.

[Explanation of symbols]

 11 plug cap 12 engine head 13 plug hole 13a upper plug hole portion 13b lower plug hole portion 14 plug cap body 15 rain cover 16 terminal metal fitting 17 ignition cable 18 opening edge portion 19 flange portion 20 circumferential groove 21 O-ring 22 partition seal wall Part 25 Inner communication hole 26 Outer communication hole

Claims (4)

[Claims] 1. A cylindrical plug cap body that can be inserted into and removed from a plug hole formed in an engine head, and a rain line into which an upper end portion of the plug cap body is fitted and which closes an opening edge portion of the plug hole. An air vent structure for a plug cap, comprising a cover and an air vent for communicating the inside of the plug hole with the outside air, wherein the plug cap includes an upper upper plug hole portion and a lower lower plug in the plug hole. A partition seal wall portion that is vertically separated from the hole portion is provided, and the air vent portion includes an outer communication hole formed in the rain cover to communicate the inside of the upper plug hole portion with the outside air, and the inside of the lower plug hole portion. An inner communication hole formed in the partition seal wall portion so as to communicate with the inside of the upper plug hole portion; The inner communication hole is arranged at a position displaced from each other with respect to the axial direction of the plug hole, and the opening end of the inner communication hole on the upper plug hole portion side is arranged at an upper position in the upper plug hole portion. The air bleeding structure of the plug cap. 2. The partition seal wall portion is attached to a flange portion integrally provided on the outer periphery of an intermediate portion in the axial direction of the plug cap body in a protruding shape, and a peripheral groove formed on the outer periphery of the flange portion. The air vent structure for a plug cap according to claim 1, further comprising an annular seal ring that is in close contact with the inner peripheral surface of the plug hole, and the inner communication hole is formed in the flange portion. 3. The air vent structure for a plug cap according to claim 2, wherein an opening end of the outer communication hole on the upper plug hole portion side is arranged at a lower position in the upper plug hole portion. 4. The partition seal wall portion is provided so that the upper plug hole portion is located above a position of a terminal fitting mounted in the plug cap body. The air vent structure for the plug cap according to the item 2 or 3.