JPH09106878A - Plug cap air bleeder structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an air bleeder structure of a plug cap 11 for effectively preventing water from entering the inside of a hole for mounting an ignition plug. SOLUTION: A plug cap 11 is provided with a detachable cylindrically shaped plug cap main body 14 in a hole 13 for mounting an ignition plug, a rain cover 15 in which the upper end part of the plug cap min body 14 is fitted in and the aperture end part of the hole 13 for mounting the ignition plug is provided. The rain cover 15 is provided with an air bleeder part 17 equipped with an air vent routes 18, 19, and 20 for communicating with the inside of the hole 13 for mounting the ignition plug 13 and atmosphere. For the air bleeder part 17, a downward air vent route 20 on the tip end side to be released to the atmosphere of the air vent routes 18, 19, and 20 is formed downward, and the air vent route release end 21 is directed downward to prevent water entry.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air vent structure for a plug cap applied to a DOHC (double overhead camshaft) type gasoline engine or the like.

[0002]

2. Description of the Related Art For example, as an air vent structure of this type,
As shown in FIGS. 5 and 6, the plug cap 1 is provided with a plug cap body 2 and a rain cover 3, and is inserted into the spark plug mounting hole and attached to the engine side of the spark plug 5, and the terminal fitting 6 is provided. The ignition cable 7 is connected through the rain cover 3 and the rain cover 3 closes the opening end of the spark plug mounting hole.

An air vent portion 9 having a ventilation passage 8 for communicating the inside of the spark plug mounting hole with the outside air is provided between the outer peripheral surface of the upper end portion of the plug cap body 2 and the inner peripheral surface of the rain cover 3. It is provided.

When the air pressure in the spark plug mounting hole is increased when the plug cap 1 is mounted in the spark plug mounting hole on the engine side or when the temperature of the engine is raised, the air inside the spark plug mounting hole 9 is evacuated. It is configured to be able to escape to the outside through the ventilation passage 8 and to prevent the plug cap 1 from popping out due to an increase in internal pressure in the spark plug attachment hole.

[0005]

However, according to the structure of the conventional air vent portion 9 described above, as shown in FIGS. 5 and 6, the open end of the air passage 8 is released by being directed sideways or upward. Therefore, when the plug cap 1 is exposed to high-pressure water when driving in the rain or when washing the vehicle, there is a risk that water will enter the holes for attaching the spark plug through the ventilation passage 8.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air vent structure for a plug cap that effectively prevents water from entering the inside of the spark plug mounting hole.

[0007]

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 an ignition plug mounting hole and an upper end portion of the plug cap body. And a rain cover that closes the opening end of the spark plug mounting hole, and the rain cover is provided with an air vent portion having a ventilation path for communicating the inside of the spark plug mounting hole with the outside air. In the air bleeding structure of the plug cap, the air bleeding portion is formed such that the end portion side of the air passage that is open to the outside air is formed downward, and the air passage open end is oriented downward.

Further, a structure may be adopted in which a water repellent treatment is applied to the end of the ventilation path on the side of the air venting portion that is open to the outside air.

Further, a structure may be employed in which a breathable membrane member having breathability and impervious to liquid is attached to the end of the ventilation passage on the side of the air vent portion where the air is released.

Further, a cylindrical body communicating with the ventilation passage is internally fitted to the end of the ventilation passage on the side of the air vent portion where the air is released to the outside, and the air vent portion and the tubular body are connected to each other. A structure in which a gas permeable membrane is held may be used.

[0011]

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, which is a hole for attaching an ignition plug formed on the engine 12 side as in the conventional case. A cylindrical plug cap body 14 formed of a resin or the like that can be inserted into and removed from the inside 13 and a rain cover 15 made of an elastic material such as rubber into which the upper end portion of the plug cap body 14 is fitted. Be prepared,
When the lower end side of the plug cap body 14 is inserted into the spark plug mounting hole 13 and the ignition cable 16 is connected to the spark plug mounted on the engine 12 side through the terminal fitting, the spark plug mounting hole The upper open end of 13 is configured to be closed by a rain cover 15.

Further, the rain cover 15 is provided with an air vent portion 17 which communicates the inside of the spark plug mounting hole 13 with the outside air, and the air vent portion 17 and the outer peripheral surface of the upper end portion of the plug cap body 14 are provided with rain. A vertical inner air passage 18 formed between the inner peripheral surface of the cover 15 and an upper air passage 19 which is continuous with the inner air passage 18 and extends upward from the rain cover 15 so as to project upward. And a downward air passage 20 that is bent downward in a U shape at the upper end of the upper air passage 19 and is formed downward. Further, the air passage release end 21 at the lower end of the downward air passage 20 is directed downward and is in an open state.

That is, in this embodiment, the upper air passage 1
9 and the downward ventilation passage 20 are formed by integrally forming a thin tubular cylinder portion on the upper surface side of the rain cover 15 so as to project upward, and bending the upper portion thereof. For example, it is configured by bending 180 degrees with a radius of 2 to 3 mm.

The first embodiment is configured as described above, and among the air passages 18, 19, 20 of the air vent portion 17,
The downward air passage 20 on the end side that is released to the outside air is formed downward, and the air passage open end 21 is directed downward and is in an open state. Even if it is flooded with water, the vent passage open end 21 does not have a direction to receive water, so that water can be effectively prevented from entering the spark plug mounting hole 13 through the vent passages 20, 19 and 18.

Further, the ventilation passages 18 and 1 of the air vent portion 17 are
The inside of the spark plug mounting hole 13 and the outside air are communicated with each other through 9 and 20, so that the inflow and outflow of air to and from the inside of the spark plug mounting hole 13 is effectively ensured.

Furthermore, since the air passage opening end 21 is directed downward, it is possible to prevent dust, other than water, from adhering to the air passage opening end 21.
It is also possible to effectively prevent the blockage of No. 1 due to dust and dust, and to effectively exhibit the air venting function of the air venting portion 17.

FIG. 2 shows a second embodiment, in which the air passage release end 2 of the downward air passage 20 in the air vent portion 17 is shown.
The surface of the end portion on the first side is subjected to a water repellent treatment to form a water repellent layer 22.

The water repellent treatment may be, for example, a method of coating a water repellent substance such as silicone or a method of spraying a so-called water repellent spray.

According to the second embodiment, in addition to the same effect as that of the first embodiment, the water-repellent function of the water-repellent layer 22 allows water to infiltrate through the downward air passage 20 by the capillary phenomenon. The water-repellent layer 22 itself can be more effectively prevented and dust and the like are less likely to adhere to the water-repellent layer 22 itself, so that the air venting function can be more effectively exerted.

FIG. 3 shows a third embodiment, in which a lower diameter portion of the downward air passage 20 in the air vent portion 17 is provided with a large diameter air passage portion 20a having a larger inner diameter.
A hollow aluminum tubular body 25 is internally fitted in the large-diameter air passage portion 20a with an air permeable membrane body 24 having air permeability and impervious to liquid.

At this time, the downward ventilation passage 20 and the aluminum cylinder 2
The hollow ventilation passage 25a in 5 is communicated with the hollow ventilation passage 25a in the up-down direction via the ventilation membrane 24. Further, the gas permeable membrane body 24 is held between the inner peripheral surface of the large-diameter air passage portion 20a and the outer peripheral surface of the aluminum tubular body 25 in a sandwiched manner.

According to the third embodiment, in addition to the effect similar to that of the first embodiment, the portion of the lower end of the downward ventilation passage 20 where the ventilation membrane 24 is arranged is directed downward.
Water does not collect on the surface of the gas permeable body 24, and the gas permeability of the gas permeable membrane 24 sufficiently functions even when exposed to water, so that intrusion of water can be more reliably prevented. Further, dust and the like are less likely to adhere to the gas permeable membrane 24 itself, and the air venting function can be more effectively exerted.

FIG. 4 shows a fourth embodiment and a third embodiment.
The configuration is almost the same as that of the above embodiment. That is, the configuration is different only in that the breathable film body 24, which is held in a sandwiched state by the large-diameter air passage portion 20a and the aluminum tubular body 25, is arranged on the air passage open end 21 side. Therefore, the same effect as the third embodiment is obtained.

As the gas permeable membrane member 24 in the third and fourth embodiments, there is, for example, the product name "POREFLON" manufactured by Sumitomo Electric Industries, Ltd.

In each of the above-described embodiments, the upper air passage 19 and the downward air passage 20 of the air vent portion 17 have a structure projecting upward from the upper surface of the rain cover 15. The structure may be provided with a downward ventilation path 20 that is formed in a protruding shape toward one side and extends downward from that position.

[0026]

As described above, according to the air vent structure of the plug cap of the present invention, the air vent portion is formed such that the end portion side of the vent passage open to the outside air is directed downward.
The open end of the air passage is directed downward, and even if the rain cover is exposed to water, the open end of the air passage is not in the direction of receiving water, and the water for the spark plug mounting hole through the air passage is Can be effectively prevented, and since the air passage open end is directed downward, it is possible to prevent dirt and dust other than water from adhering to the air passage open end. There is an advantage that blockage due to dust can be effectively prevented and the air venting function of the air venting portion can be effectively exerted.

Further, if the structure is such that the end of the ventilation path on the side of the air venting portion that is exposed to the outside air is made water repellent,
The water-repellent function of the water-repellent layer makes it possible to more effectively prevent water from entering due to capillarity through the ventilation path, and the water-repellent layer itself is less prone to dust and dirt adhesion, making it possible to more effectively perform the air venting function. There is.

Further, if the ventilation passage end on the side where the air is released to the outside air is provided with a ventilation membrane that is breathable and does not allow the passage of liquid, the ventilation of the ventilation passage end can be improved. Since the part where the membrane is placed faces downward, water does not collect on the surface of the breathable membrane, the breathability of the breathable membrane functions sufficiently even when exposed to water, and it is possible to prevent water from entering more reliably. , The breathable film itself is less likely to attach dust and dirt,
There is an advantage that the air venting function can be more effectively exerted.

[Brief description of the 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.

FIG. 3 is a cross-sectional view of essential parts showing a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of main parts showing a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a main part showing a conventional example.

FIG. 6 is a sectional view of a main part showing a conventional example.

[Explanation of symbols]

 11 Plug Cap 13 Spark Plug Attachment Hole 14 Plug Cap Main Body 15 Rain Cover 17 Air Vent 18 Inner Vent 19 Upper Vent 20 Downward Vent 21 Vent Open End 22 Water Repellent Layer 24 Vent Membrane 25 Aluminum Cylinder

Claims (4)

[Claims] 1. A tubular plug cap body that can be inserted into and removed from a spark plug mounting hole, and an upper end portion of the plug cap body is fitted into the spark plug mounting hole, and the opening end of the spark plug mounting hole is closed. In the air vent structure of the plug cap, the air vent is provided with a cover, and the rain cover is provided with an air vent having an air passage for communicating the inside of the spark plug attachment hole with the outside air. An air vent structure for a plug cap, characterized in that an end portion side of the plug cap is formed downward and the vent passage open end is directed downward. 2. The air bleed structure for a plug cap according to claim 1, wherein a water repellent treatment is applied to an end of the air passage of the air bleeder which is open to the outside air. 3. An air permeable membrane member having air permeability and impervious to a liquid is attached to an end portion of the air passage of the air vent portion on the side of being released to the outside air. Air vent structure of plug cap. 4. A cylindrical body communicating with the ventilation passage is internally fitted to an end of the ventilation passage on the side of the air bleeder that is open to the outside air, and the air bleeder and the cylindrical body are connected to each other. The air vent structure for a plug cap according to claim 3, wherein the vent film body is held.