JP3075149B2 - Plug cap for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug cap for an internal combustion engine used in a connection portion between a spark plug and a plug cord of an internal combustion engine of an automobile or the like.

[0002]

2. Description of the Related Art This type of plug cap for an internal combustion engine is
As shown in FIG. 6, a plug cap pipe 51 made of synthetic resin into which the plug cord C is inserted, a rubber rain cover 52 attached to the upper end of the plug cap pipe 51, And a rubber bush 53 attached to the lower end. The plug cap pipe 51 is housed in a plug hole of the internal combustion engine, and the rubber bush 53 is fitted into a spark plug installed in the plug hole. In addition to the connection, the opening of the plug hole is closed by the rain cover 52.

As shown in FIG. 7A, the rain cover 52 has a concave portion 52a on the inner peripheral surface thereof, and the concave portion 52a has a projection formed at the upper end of the plug cap pipe 51. The fitting state is maintained by fitting the 51a. The rain cover 52 has a part fitted into the plug hole H. As shown in FIG. 3B, the outer surface of the fitted part is radially inward. A sealing portion 52b that protrudes outward so as to be elastically deformable is formed. The sealing portion 52b is in close contact with the inner peripheral surface of the plug hole H, thereby preventing water from entering the plug hole H from outside.

[0004]

By the way, in the plug cap for an internal combustion engine as described above, the sealing portion 52b is used.
Is required to be completely adhered to the inner peripheral surface of the plug hole H, so that the outer diameter D1 of the sealing portion 52b is made larger than the inner diameter D2 of the plug hole H as shown in FIG. When the rain cover 52 is fitted into the plug hole H, the sealing portion 52b is deformed or compressed by rubber elasticity so as to be completely adhered to the inner peripheral surface of the plug hole H.

In the rain cover 52 having such a structure,
As the outer diameter D1 of the sealing portion 52b is increased, the adhesion to the inner peripheral surface of the plug hole H is increased, and the sealing performance is improved. In order to enhance the sealing performance, a large force is required when the plug cap is attached to and detached from the plug hole H because the frictional force generated between the plug cap and the stop portion 52b increases. There is a problem that attachment and detachment of the engine itself becomes difficult.

Further, as described above, since the outer diameter D1 of the sealing portion 52b greatly affects the sealing performance, even if the inner diameter D2 of the plug hole H differs by about 1 mm, for example, the plug hole H has an outer diameter suitable for it. It is necessary to prepare the rain cover 52 having the sealing portion 52b, which hinders cost reduction by sharing parts.

It is an object of the present invention to provide a plug cap for an internal combustion engine which has high sealing performance, is easy to attach and detach, and is versatile.

[0008]

SUMMARY OF THE INVENTION To solve the above problems, the present invention provides a plug cap pipe housed in a plug hole of an internal combustion engine with a plug cord inserted, and an upper end of the plug cap pipe. And a rain cover which is fitted into the plug hole and fitted into the plug hole to close the opening of the plug hole. And a second locking portion formed below the first locking portion. The rain cover is engaged with the second locking portion to form the plug cap pipe with respect to the plug cap pipe. A second locked portion that positions the rain cover, a first lower locked portion that engages with the first locking portion without compressing the rain cover up and down, and A first upper locked portion that engages with the first locking portion in a contracted state and maintains a compressed state of the first upper locking portion, and the first lower locked portion and the second locked portion are connected to each other; In the meantime, a thin sealing portion that projects slightly outwardly without compressing the rain cover up and down, projects outward while compressing the rain cover up and down, and closely adheres to the inner surface of the plug hole. It was formed.

The first locking portion is formed by a rib protruding from the outer peripheral surface of the plug cap pipe, and the first upper locked portion and the first lower locked portion are formed by the rib. May be configured by a groove to be fitted,
The second locking portion may be constituted by a projection projecting from the outer peripheral surface of the plug cap pipe, and the second locked portion may be constituted by a concave portion into which the projection is fitted.

Preferably, the rain cover is formed of rubber, and a rubber bush fitted to a terminal of an ignition plug projecting upward from a bottom of the plug hole is attached to a lower end of the plug cap pipe. You may.

[0011]

Embodiments will be described below with reference to the drawings. As shown in FIG. 1, a plug cap 1 for an internal combustion engine includes a plug cap pipe 10 made of a synthetic resin into which a plug cord (not shown) is inserted, and a rain cap mounted on an upper end of the plug cap pipe 10. It comprises a cover 20 and a rubber bush 30 mounted on the lower end of the plug cap pipe 10.

As shown in FIG. 2, the plug cap pipe 10 has a cut-out portion 12 for inserting a plug cord (not shown) in a peripheral surface of an upper end portion of a tubular pipe body 11. A rib 13 is formed on the lower outer peripheral surface of the notch 12 so as to protrude radially outward over the entire circumference. A projection 14 is formed below the rib 13 so as to protrude radially outward over the entire circumference of the outer peripheral surface thereof at regular intervals.

As shown in FIG. 3, the rain cover 20 has a cylindrical cover body 21 in which the upper end of the plug cap pipe 10 is inserted and whose upper end is closed. A flange 28 protrudes outward over the entire circumference, and a groove 28a is formed on the lower surface of the flange 28 so as to fit with a ridge formed on a peripheral portion of a plug hole of a cylinder head of the engine. It is formed over the entire lower surface.

The cover body 21 includes a plug hole insertion portion 2 in which the lower side of the flange portion 28 is inserted into a plug hole.
A cord insertion portion 23 having a cord insertion hole 23a for inserting a plug cord is formed on the upper side of the flange portion 28 so as to protrude to the side.

On the inner surface of the cover body 21, a pair of upper and lower circumferential grooves 24, 25 into which the ribs 13 of the plug cap pipe 10 are fitted are formed at regular intervals on the upper side thereof. On the lower side of 25, a recess 26 is formed over the entire circumference to fit the projection 14 of the plug cap pipe 10 and position the rain cover 20 with respect to the plug cap pipe 10.

The plug hole insertion portion 22 includes:
Between the circumferential groove 25 and the concave portion 26, a thin sealing portion 27 slightly protruding outward is formed over the entire circumference, and by compressing the cover body 21 in the vertical direction, The sealing portion 27 projects outward. The outer diameter of the sealing portion 27 is smaller than the inner diameter of the plug hole to which the plug cap 1 for the internal combustion engine is attached when the cover body 21 is not compressed up and down, and the cover body 21 is compressed up and down. In the state, the diameter is larger than the inner diameter of the plug hole.

The circumferential grooves 24 and 25 are provided in the cover body 2.
1 to maintain the compressed state and the non-compressed state, respectively. When the rib 13 of the plug cap pipe 10 is fitted in the lower peripheral groove 25, the cover body 21 is held in the non-compressed state. When the rib 13 is fitted into the upper peripheral groove 24, the cover body 21 is held in a compressed state.

The cover body 21 is provided with the flange 2
8 and a vertical groove 21b formed on the inner surface of the cover main body 21 and connected to the through hole 21a, and is fitted into the through hole 21a and the cover main body 21. The outer peripheral surface of the plug cap pipe 10 and the vertical groove 21b form an air vent passage in the plug hole (see FIG. 1).

In the plug cap 1 for an internal combustion engine constructed as described above, first, the terminal portion of the plug cord is inserted into the cord insertion hole 23a of the rain cover 20, and the pipe is inserted through the notch 12 of the plug cap pipe 10. Body 1
1, and the rain cover 20 is attached to the upper end of the plug cap pipe 10 while being housed in the upper half of the pipe body 11. When mounting the rain cover 20, first, the protrusion 1 of the plug cap pipe 10 is used.
4 is fitted into the concave portion 26 of the rain cover 20, and the positioning with respect to the plug cap pipe 10 is performed. Then, the rib 13 of the plug cap pipe 10 is fitted into the lower circumferential groove 25 of the rain cover 20, and 21
Are kept in a non-compressed state (see FIG. 1). Therefore,
In this state, the outer diameter of the sealing portion 27 is smaller than the inner diameter of the plug hole.

The lower half of the pipe body 11 accommodates a discharge tube unit (not shown) connected to the plug cord, connection terminals, and the like. The pipe body 11 is held so as to hold these discharge tube units and the like. A substantially cylindrical rubber bush 30 is fitted to a lower end of the rubber bush 30.

When the plug cap 1 for an internal combustion engine, to which the plug cord (not shown) is mounted, is mounted on an engine, as shown in FIG. The rubber bush 30 is inserted into a plug hole H formed in the head C, and the rubber bush 30 is fitted into a terminal of the ignition plug P projecting from the bottom surface of the plug hole H.
Is connected to the ignition plug P. At this time, as shown in FIG.
The plug hole insertion portion 22 is inserted into the plug hole H. However, since the sealing portion 27 is separated from the inner peripheral surface of the plug hole H, the plug hole insertion portion 22 can be easily inserted. .

Next, when the rain cover 20 is pushed down, the lower end of the cover body 21 is brought into contact with the projection 14 of the plug cap pipe 10 and the recess 26 of the rain cover 20.
As shown in FIG. 5, the cover main body 21 is compressed in the vertical direction, and the rib 13 of the plug cap pipe 10 is fitted into the upper peripheral groove 24 of the rain cover 20 as shown in FIG. By doing so, the compressed state is maintained.

In a state where the cover body 21 is not compressed, the sealing portion 27 slightly protrudes outward and is formed in a thin shape. As shown in the figure, the sealing portion 27 protrudes outward and closely adheres to the inner peripheral surface of the plug hole H in a press-contact state, and the flange portion 28 of the rain cover 20 descends, so that the groove 28a is formed in the plug hole H. Of the internal combustion engine plug cap 1 is completed.

Thus, when removing the plug cap 1 for the internal combustion engine attached to the engine, it can be easily removed simply by pulling the rain cover 20 upward. That is, as described above, the rain cover 20
Since the lower end of the plug cap pipe 10 is positioned on the plug cap pipe 10, by pulling up the rain cover 20, first, the rib 13 of the plug cap pipe 10 fitted into the upper circumferential groove 24 of the rain cover 20 is disengaged. Since the compressed state of the cover main body 21 is released and the sealing portion 27 is separated from the inner peripheral surface of the plug hole H with this, the rib 13 is moved to the lower peripheral groove 25 when the rain cover 20 is pulled up as it is. Plug cap for internal combustion engine from the engine without being fitted and receiving large frictional resistance.
Can be removed.

As described above, the plug cap 1 for the internal combustion engine compresses or expands the cover body 21 in the vertical direction with the plug hole insertion portion 22 of the rain cover 20 inserted into the plug hole H. Thereby, the sealing portion 27 can be brought into close contact with and separated from the inner peripheral surface of the plug hole H, and can be attached to and detached from the engine while the sealing portion 27 is separated from the inner peripheral surface of the plug hole H. Even if the outer diameter of the sealing portion 27 in the sealed state is increased to enhance the sealing performance, a large frictional resistance does not occur when the plug cap 1 for the internal combustion engine is attached to or detached from the engine.
Can be easily attached and detached. Further, since the plug cap 1 for the internal combustion engine can be easily attached and detached in this manner, if the outer diameter of the sealing portion 27 in the sealed state is set to be somewhat large in advance, the inner diameter of the plug hole H is about 1 mm. Even if it fluctuates, sufficient sealing performance can be secured.

In this embodiment, the rib 13
The compressed state and the non-compressed state of the cover main body 21 are maintained by fitting of the peripheral grooves 24 and 25 with each other. For example, a protrusion may be provided instead of the rib 13,
A hole for receiving the protrusion may be formed instead of 5.

[0027]

As described above, the plug cap for an internal combustion engine according to the present invention enables the sealing portion to adhere to and separate from the inner peripheral surface of the plug hole with the rain cover inserted into the plug hole. Therefore, even if the outer diameter of the sealing portion in the sealed state is increased to enhance the sealing performance, the plug cap can be easily attached and detached.

Since the plug cap can be easily attached and detached as described above, if the outer diameter of the sealing portion in the sealed state is set to be large in advance, even if the inner diameter of the plug hole slightly changes. Since sufficient sealing performance can be secured, cost reduction can be achieved by sharing parts.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an embodiment according to the present invention.

FIG. 2 is a side view showing the plug cap pipe according to the first embodiment.

FIG. 3 is a sectional view showing the rain cover according to the first embodiment;

FIG. 4 is a process chart showing a mounting method of the same.

FIG. 5 is a process chart showing an attachment method of the above.

FIG. 6 is a partial sectional view showing a conventional example.

FIG. 7 is a cross-sectional view showing a mounting method of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plug cap for internal combustion engines 10 Plug cap pipe 11 Pipe main body 12 Notch section 13 Rib 14 Projection section 20 Rain cover 21 Cover main body 22 Plug hole insertion section 23 Code insertion section 24, 25 Circumferential groove 26 Recess 27 Sealing section 28 Flange 30 Rubber bush C Cylinder head c Ridge H Plug hole

Claims (5)

(57) [Claims] A plug cap pipe which is accommodated in a plug hole of an internal combustion engine with a plug cord inserted therethrough, and which is externally fitted to an upper end portion of the plug cap pipe and is fitted in the plug hole and An internal combustion engine plug cap having a rain cover for closing an opening of a plug hole, wherein a first locking portion is provided at an upper end of the plug cap pipe;
A second locking portion formed below the first locking portion, wherein the rain cover is engaged with the second locking portion to position the rain cover with respect to the plug cap pipe. A second locked portion to be performed, a first lower locked portion that engages with the first locking portion without compressing the rain cover up and down, and a second lower locked portion that engages with the rain cover up and down. A first upper locked portion that engages with the first locking portion and maintains a compressed state of the first upper locked portion, and the first lower locked portion and the second upper locked portion.
Between the locked portion, the rain cover slightly protrudes outward without compressing the rain cover up and down, and protrudes outward with the rain cover compressed up and down to closely adhere to the inner surface of the plug hole. A plug cap for an internal combustion engine, wherein a plug-like sealing portion is formed. 2. The first locking portion is constituted by a rib projecting from an outer peripheral surface of the plug cap pipe, and the first upper locked portion and the first lower locked portion are formed by the rib. The plug cap for an internal combustion engine according to claim 1, wherein the plug cap is formed by a fitting groove. 3. The plug according to claim 2, wherein the second locking portion is formed by a protrusion projecting from an outer peripheral surface of the plug cap pipe, and the second locked portion is formed by a concave portion into which the protrusion is fitted. Item 3. A plug cap for an internal combustion engine according to item 1 or 2. 4. The plug cap for an internal combustion engine according to claim 1, wherein the rain cover is formed of rubber. 5. The plug cap pipe according to claim 1, wherein:
5. The plug cap for an internal combustion engine according to claim 1, further comprising a rubber bush fitted to a terminal of an ignition plug projecting upward from a bottom of the plug hole.