JPH09260016A - Plug cap mechanism for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably prevent a plug cord from separating from an internal combustion engine by engaging an engaging piece protrusively arranged outward from a plug hole inserting part outer peripheral surface of a rain cover and an engaging piece protrusively arranged inward from a collar of a plug hole. SOLUTION: A plug cap pipe 10 into which a plug cord is inserted, is inserted from an opening part of a plug hole H having a collar 29 of an internal combustion engine, and an opening part is blocked up by a rain cover 20. This rain cover 20 has an almost cylindrical cover main body 21 to block up the upper end and a skirt part 28 overhanging outside over its whole circumference from a central part of the cover main body 21, and a protrusive strip 31 is integrally and protrusively formed inward from the inner peripheral upper end of the collar 29 formed in a peripheral edge part of the plug hole H, and plural protrusive parts 32 are integrally and protrusively formed outward from the outer periphery of the cover main body 21. Since this protrusive strip 31 and the protrusive parts 32 are engaged with each other, the plug cord can be reliably prevented from separating from the internal combustion engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug cap mechanism for an internal combustion engine used in a connecting portion between an ignition plug and a plug cord of an internal combustion engine such as an automobile.

[0002]

2. Description of the Related Art A conventional plug cap for an internal combustion engine (conventional example 1) has a plug cord (high voltage wire) C as shown in FIG.
A synthetic resin plug cap pipe 1 through which the
The plug cap pipe 1 comprises a rubber rain cover 2 mounted on the upper end portion thereof, and a rubber bush 3 mounted on the lower end portion of the plug cap pipe 1. The rubber bush 3 is housed in the plug hole H of Eg to be fitted and connected to the spark plug 4 installed in the plug hole H, and the opening of the plug hole H is opened by the rain cover 2 as shown in FIG. Is designed to be blocked.

The rain cover 2 has a recess 2a on its inner peripheral surface, and by fitting the projection 1a formed at the upper end of the plug cap pipe 1 into the recess 2a, It is designed to hold the installed state. Further, a part of the rain cover 2 is fitted into the plug hole H, and the outer peripheral surface of the fitted portion is a seal which is elastically deformable and radially outwardly projected outward. A stop 2b is formed. The sealing portion 2b (elastic pressing body) is brought into close contact with the inner peripheral surface of the opening of the plug hole H to prevent water from entering the plug hole H from the outside. FIG.
Reference numeral 5 in 6 indicates a terminal for connecting the plug cord C to the ignition plug 4, and reference numeral 6 indicates a rocker cover.

Alternatively, as shown in FIG. 18, there is an example (conventional example 2) in which the O-ring 8 is used as the sealing portion.

[0005]

By the way, in the plug cap mechanisms for internal combustion engines of the conventional examples 1 and 2 as described above, the joining force between the spark plug 4 and the terminal 5 and the rain cover 2 are used.
The plug cord C is disengaged from the internal combustion engine Eg by the frictional force between the sealing portion 2b and the inner peripheral surface of the opening of the plug hole H and the frictional force between the rubber bush 3 and the ignition plug 4. Although the structure is for preventing, when the plug cord C and the internal combustion engine Eg are coupled only by such joining force and frictional force, the insertion of the plug cord C by the worker may be halfway (improper installation). When the engine accessory is hooked on the plug cord C when the peripheral engine accessory is attached after the plug cord C is attached, the plug cord C may be separated from the ignition plug 4. As described above, when proper connection cannot be obtained between the spark plug 4 and the plug cord C, the ignition energy cannot be transmitted to the spark plug 4, and the spark plug misfires, so There was a risk of poor starting and poor running performance.

Therefore, a first object of the present invention is to provide a plug cap mechanism for an internal combustion engine which can be easily attached and detached and can reliably prevent the plug cord C from being separated from the internal combustion engine Eg.

Further, in the conventional example 2, the plug hole H
Water was prevented by contact between the sealing portion 2b or the O-ring 8 and the inner wall of the rocker cover 6 and the plug hole H, but the sealing structure portion such as the sealing portion 2b and the O-ring 8 is used for a long time. It may deteriorate with age, resulting in gaps and poor waterproofness. As a result, when water enters the plug hole H, electricity leaks from between the spark plug 4 and the rubber bush 3, and there is a risk that the internal combustion engine may start poorly or run poorly.

Therefore, a second object of the present invention is to prevent deterioration of waterproofness even if the seal structure part deteriorates over time due to long-term use, and prevent start-up failure and runnability of the internal combustion engine. An object is to provide a plug cap mechanism for an internal combustion engine.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 has an opening portion of the plug hole having a collar in a state where the plug cord is inserted into the plug hole of the internal combustion engine. As a plug cap mechanism for an internal combustion engine that closes a plug cap pipe that is housed in the plug hole of the internal combustion engine in a state where the plug cord is inserted, and is externally fitted to an upper end portion of the plug cap pipe. A rain cover having a skirt that fits into the flange of the plug hole, and a plug hole insertion portion that is fitted into the plug hole and closes the opening portion of the plug hole; and a rain cover that covers the opening portion of the plug hole. And an engaging means that is detachably engaged with the.

The engaging means includes a first engaging element projecting outward from an outer peripheral surface of the plug hole inserting portion of the rain cover, and an inward direction from the brim of the plug hole. And a second engaging element that is projected and engages with the first engaging element.

It is desirable that the second aspect of the invention has a notch formed in the second engagement element for fitting the first engagement element.

[0012] Alternatively, in the invention according to claim 3, the engaging means includes a first screw portion formed on the skirt of the rain cover and the plug so as to be screwed into the first screw portion. And a second screw portion formed on the flange of the hole.

Alternatively, in the invention as set forth in claim 4, the engaging means has a step portion formed with a plurality of steps on either one of the skirt of the rain cover and the collar of the plug hole. And formed on the other of the skirt of the rain cover and the flange of the plug hole so as to engage with any step of the plurality of steps of the step portion to position the rain cover in the advancing / retreating direction. And an engaging piece. Here, the engagement piece is formed to have elasticity in a direction facing the step portion.

Further, the plug cap mechanism for an internal combustion engine is provided with a sealing means for keeping the inside of the plug hole watertight.

Here, the sealing means is an elastic pressing body which is formed on at least one of the rain cover and the flange of the plug hole and is in close contact with the surface of the other, and a plug cap mechanism for an internal combustion engine. .

Alternatively, the sealing means is arranged at a sandwiching position sandwiched between the inner surface of the skirt of the rain cover and the tip surface of the collar of the plug hole as the rain cover advances. .

Specifically, the sealing means is a ridge formed on at least one of the inner surface of the skirt of the rain cover and the tip surface of the collar of the plug hole at the sandwiching position.

Alternatively, the sealing means is an O-ring inserted in the sandwiched position.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

{First Embodiment} A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a plug cap PC for an internal combustion engine according to this embodiment has a plug cap pipe 10 made of a synthetic resin into which a plug cord C is inserted, and an elastic member attached to an upper end portion of the plug cap pipe 10. The synthetic resin rain cover 20 and the rubber bush 30 attached to the lower end of the plug cap pipe 10 are included.

The plug cap pipe 10 has an opening (notch) 12 for inserting the plug cord C in the peripheral surface of the upper end of a cylindrical pipe body 11. The opening 1
On the lower outer peripheral surface of 2, there is formed a projection 14 that projects radially outward over the entire circumference. The connection terminal 17 of the spark plug 16 is fitted in the lower half of the pipe body 11, and a substantially tubular rubber bush 30 is fitted to the lower end of the pipe body 11 so as to hold them.

As shown in FIGS. 2 and 3, the rain cover 20 has a substantially cylindrical cover main body 21 with the upper end closed, into which the upper end of the plug cap pipe 10 is inserted, and the center of the cover main body 21. And a skirt 28 projecting outward from the entire circumference of the skirt.
A groove 28a that fits into the flange 29 formed at the peripheral edge portion of the plug hole H of the cylinder head of the internal combustion engine is formed on the lower surface of the above.

In the cover body 21, as shown in FIG. 1, the lower side of the skirt 28 is a plug hole insertion portion 22 which is inserted into the plug hole H, and the upper side of the skirt 28 is
A cord insertion portion 23 having a cord insertion hole 23a for inserting the plug cord C is formed in a state of protruding laterally.

On the inner surface of the cover body 21, there is formed a recess 26 for fitting the projection 14 of the plug cap pipe 10 to position the rain cover 20 with respect to the plug cap pipe 10 over the entire circumference.

The cover body 21 has a cord insertion portion 2
A through hole 21a penetrating the inside and outside at the upper end of 3 and a vertical groove 21 formed on the inner surface of the cover body 21 and connected to the through hole 21a.
b and the outer peripheral surface of the plug cap pipe 10 fitted in the through hole 21a and the cover body 21 and the vertical groove 2
With 1b, an air vent passage in the plug hole H is formed.

Then, as an engaging means for detachably engaging the rain cover 20 with respect to the flange 29 of the plug hole H, as shown in FIG. The projected ridge 31 (second engaging element),
The cover body 21 is provided with a plurality of convex portions 32 (first engaging elements) integrally formed to project outward from the outer circumference. In addition, a notch 33 for allowing the protrusion 32 to be inserted from above is formed at a predetermined position of the protrusion 31 in correspondence with the shape and number of the protrusions 32.

Further, the groove wall surface of the groove 28a of the skirt 28 is a seal for making the inside of the plug hole H watertight by closely contacting the upper end surface of the collar 29 and elastically pressing the convex portion 32 toward the protrusion 31 side. The projecting ridge 34 (sealing means) is formed. The distance in the height direction between the lower end point of the protrusion 34 and the upper end surface of the protrusion 32 is set to be slightly smaller than the height dimension of the protrusion 31.

In the above structure, when the plug cord C is attached, first, the end portion of the plug cord C is inserted into the cord insertion hole 23a of the rain cover 20, and further the opening 12 of the plug cap pipe 10 is inserted into the pipe body 11. The rain cover 20 is attached to the upper end of the plug cap pipe 10 in a state where it is inserted and accommodated in the upper half of the pipe body 11.
Attach.

Then, the internal combustion engine plug cap PC having the plug cord C attached thereto is assembled to the internal combustion engine. At this time, attach the rubber bush 30 to the plug hole H.
While fitting into the terminal of the ignition plug 16 protruding from the bottom surface of the cover body 2 while connecting the connection terminal 17 accommodated in the lower half of the pipe body 11 to the ignition plug 16,
The first plug hole insertion portion 22 is inserted into the plug hole H formed in the cylinder head of the internal combustion engine.

At this time, as shown in FIG. 2, the plurality of protrusions 32 are inserted into the notches 33 of the corresponding protrusions 31, respectively. Then, when the rain cover 20 is lowered and the upper end of the convex portion 32 reaches a height position below the lower end of the protrusion 31, the rain cover 20 is moved around the central axis of the pipe body 11 (R in FIG. 2).
3) as shown in FIG.
Dive below. Then, the rain cover 20
The upper side of the protrusion 32, the protrusion 3
The lower surface of 1 is abutted, and the above-mentioned disengagement is prevented. Therefore, the spark plug 16 and the plug cord C can be surely coupled, and it is possible to prevent misfire of the spark plug 16, start-up failure of the internal combustion engine, and runnability.

A ridge 34 for sealing is formed on the groove top wall surface of the groove 28a of the skirt 28, and the distance between the lower end point of this ridge 34 and the upper end surface of the convex portion 32 in the height direction is defined by the ridge. 31
Since it is set to be slightly smaller than the height dimension of the ridge, the ridge 34 is brought into close contact with the brim 29 by sandwiching the ridge 31 by elastic restoration of the ridge 34 and the convex portion 32 on the rain cover 20 side,
Therefore, the inside of the plug hole H can be easily kept watertight.

When it becomes necessary to detach the plug cord C from the plug hole H, for example, when the spark plug 16 is replaced, the rain cover 20 is rotated around the central axis of the pipe body 11 (Rb direction in FIG. 2). And the convex portion 32 makes the protrusion 3
When reaching the position matching the notch 33 of No. 1, the protrusion 32 is pulled out from the notch 33, and the plug cap pipe 1
0 and the rain cover 20 may be removed from the plug hole H. That is, since the rain cover 20 can be easily detached from the plug hole H by the rotating operation and the pulling operation, the internal combustion engine plug cap PC can be removed from the internal combustion engine without receiving a large frictional resistance as compared with the conventional case.

{Second Embodiment} FIG. 4 is a sectional view showing an internal combustion engine plug cap according to a second embodiment of the present invention, and FIG. 5 is a perspective view thereof. 4 and 5, elements having the same functions as those in the first embodiment are designated by the same reference numerals. In the rain cover 20 of this embodiment, a synthetic rubber cover body 21 and a substantially annular synthetic resin or metal skirt 28 made of aluminum or the like arranged around the cover body 21 are configured as separate parts. The skirt 28 is rotatable about the cover body 21 as a central axis.

The engaging means for detachably engaging the rain cover 20 with the flange 29 of the plug hole H is, as shown in FIG. 4, a first screw formed on the inner surface of the lower end of the skirt 28. It is composed of a portion 41 and a second screw portion 42 formed on the outer peripheral surface of the collar 29 of the plug hole H and screwed into the first screw portion 41.

A substantially annular connecting portion 43a is formed on the cover body 21, and the lower surface of the connecting portion 43a is
The elastic pressing body 43 serves as a sealing means for closely pressing the inner wall of the plug hole H to make the inside of the plug hole H watertight.
The (sealing portion) is formed so as to hang down in a substantially cylindrical shape around the entire circumference of the plug cap pipe 10. The outer peripheral surface of the elastic pressing body 43 is formed in a substantially mountain shape, and the outer diameter of the top of the mountain surface is set to be slightly larger than the inner diameter of the plug hole H. Since other configurations are similar to those of the first embodiment,
Description is omitted.

In the above structure, when the plug cap PC for an internal combustion engine to which the plug cord C is attached is assembled to the internal combustion engine, the plug hole insertion portion 22 is inserted into the plug hole H as shown in FIG. With the plug cord C attached to the engine plug cap PC, the skirt 28 is rotated in the horizontal direction (Ro direction in FIG. 5), and the first screw portion 41 on the skirt 28 side and the second screw portion on the plug hole H side are rotated. The screw part 42 of is screwed. Then, even if the rain cover 20 attempts to be removed upward, the removal is prevented unless the rotational force is applied to the internal combustion engine plug cap PC. Therefore, the spark plug 16 and the plug cord C can be surely coupled, and it is possible to prevent misfire of the spark plug 16, start-up failure of the internal combustion engine, and runnability.

Further, since the cover body 21 is provided with the elastic pressing body 43, the elastic pressing body 43 elastically restores the elastic pressing body 43 and the inner wall of the plug hole H in close contact with each other. Can be kept watertight.

When it becomes necessary to remove the plug cord C from the plug hole H, such as when the spark plug 16 is replaced, the entire internal combustion engine plug cap PC is rotated about the central axis (see FIG. 5). Rb direction), and the first screw portion 41
Then, the screwing of the second screw portion 42 is released, and the plug cap pipe 10 and the rain cover 20 may be removed from the plug hole H. That is, since the rain cover 20 can be easily detached from the plug hole H by the rotating operation and the pulling operation, the internal combustion engine plug cap PC can be removed from the internal combustion engine without receiving a large frictional resistance as compared with the conventional case.

{Third Embodiment} FIG. 6 is a sectional view showing an internal combustion engine plug cap according to a third embodiment of the present invention.
FIG. 8 is a perspective view of the same, and FIGS. 8 and 9 are sectional views showing the operation of attaching the internal combustion engine plug cap to the cylinder head of the internal combustion engine. 6 to 9, elements having the same functions as those in the first and second embodiments are designated by the same reference numerals. In the rain cover 20 of this embodiment, similar to the second embodiment, the cover body 21 made of synthetic rubber and the skirt 28 made of synthetic resin or aluminum or the like having a substantially annular shape arranged around the cover body 21 are separate from each other. Is configured as. As shown in FIG. 6, the engaging means for detachably engaging the rain cover 20 with the flange 29 of the plug hole H has a step-like step on the outer peripheral surface of the flange 29 of the plug hole H in cross section. It is composed of a step portion 51 formed by the above, and an engagement piece 52 which is formed in a part of the skirt 28 and engages with the step portion 51. The stepped portion 51 of this embodiment may be one in which a plurality of grooves are formed in parallel, or may be screwed in the same manner as the second screw portion 42 of the second embodiment. May be. Further, as shown in FIG. 7, the engaging piece 52 is formed by cutting out a predetermined position of the skirt 28 into a substantially rectangular shape, and only the upper end of the skirt 28.
It is integrally formed so as to hang down in a state of being connected to, and a chevron projection 53 for engaging with the step portion 51 of the collar 29 of the plug hole H is formed near the lower end of the inner surface. There is. Here, the chevron projections 53 are used for the rain cover 2.
Since it is integrally formed of the same elastic material as 0,
Outward (D1 direction) and inward (D2 direction) like inside
It is elastically deformable. The cover body 21 is formed with an elastic pressing body 43 similar to that of the second embodiment. The other configurations are similar to those of the first and second embodiments, and thus the description thereof will be omitted.

In the above structure, when the plug cap PC for an internal combustion engine, to which the plug cord C is attached, is assembled to the internal combustion engine, the plug hole insertion portion 22 is inserted into the plug hole H as shown in FIG. With the plug cord C attached to the engine plug cap PC, the elastic cap 43 is slid into the plug hole H while the internal combustion engine plug cap PC is lowered. Then, FIG.
As described above, the chevron-shaped projection 53 of the engagement piece 52 contacts the uppermost end point of the step portion 51. When the internal combustion engine plug cap PC is further lowered in this state, as shown in FIG.
Is elastically deformed in the outward direction (D1 direction), and the mountain-shaped projection 53 descends beyond the mountain portion of the stepped portion 51. In this manner, the internal combustion engine plug cap PC is lowered while repeating the elastic deformation of the engaging piece 52 by the number of peaks of the step portion 51, and the chevron projection 53 is formed in the valley portion at a predetermined position of the step portion 51 as shown in FIG. Engage. Then, even if the rain cover 20 tries to separate upward, such separation is prevented. The step 5
Since the number of peaks of 1 is set to be plural, even if the chevron projection 53 is disengaged upward from the trough of the stepped portion 51 at a predetermined position, the chevron projection 53 is formed in the trough further above the stepped portion 51. Since they engage, further disengagement can be prevented. Therefore, the spark plug 16 and the plug cord C can be surely coupled, and it is possible to prevent misfire of the spark plug 16, start-up failure of the internal combustion engine, and runnability.

Further, as in the second embodiment, the cover body 2
1 is provided with the elastic pressing body 43, the elastic pressing body 43
Due to the elastic restoration, the elastic pressing body 43 and the inner wall of the plug hole H are in close contact with each other, so that the inside of the plug hole H can be easily watertight.

{Fourth Embodiment} FIG. 10 shows a fourth embodiment of the present invention.
FIG. 11 is a sectional view showing the internal combustion engine plug cap of the embodiment, FIG. 11 is a perspective view thereof, and FIGS. 12 and 13 are sectional views showing an operation of attaching the internal combustion engine plug cap to a cylinder head of the internal combustion engine. Note that FIGS.
Then, the elements having the same functions as those in the first embodiment, the second embodiment and the third embodiment are designated by the same reference numerals. In the rain cover 20 of this embodiment, the second
Similar to the embodiment and the third embodiment, the cover body 21 made of synthetic rubber and the skirt 28 made of synthetic resin or aluminum or the like having a substantially annular shape which is arranged around the cover body 21 are formed as separate bodies from each other. . The engaging means for detachably engaging the rain cover 20 with the flange 29 of the plug hole H is composed of the step portion 51 and the engaging piece 52 similar to those in the third embodiment. That is, the step portion 51 of this embodiment is the second screw portion 42 of the second embodiment.
Is similar to Further, as shown in FIG. 11, the engagement piece 52 is integrally formed so as to hang down in a state where a predetermined position of the skirt 28 is cut out in a substantially rectangular shape and only the upper end is connected to the skirt 28. Near the bottom of the surface,
A chevron-shaped projection 53 for engaging with the stepped portion 51 of the collar 29 of the plug hole H is formed. Here, the chevron protrusion 53
Is integrally formed of the same elastic material as that of the rain cover 20, so that it can be elastically deformed in the outward direction (D1 direction) and the inward direction (D2 direction) as shown in FIG.

Further, as a sealing means for making the inside of the plug hole H watertight, it is sandwiched between the top surface 57 of the groove 28a formed on the lower surface of the skirt 28 and the collar 29 of the plug hole H. An O-ring 55 is used. In addition, the groove 28a of the skirt 28 of the rain cover 20
In order to sandwich the O-ring 55 inside and prevent the displacement thereof, a sandwiching projection 56 is hung down over the entire circumference inside the O-ring mounting position on the top surface 57 of the groove 28a.

The ridge 3 described in each of the above-described embodiments.
4 and the elastic pressing body 43 are omitted. The other configurations are the same as those in the above-described embodiments, and thus the description thereof will be omitted.

In the above structure, when the plug cap PC for an internal combustion engine to which the plug cord C is attached is assembled to the internal combustion engine, the plug hole insertion portion 22 is inserted into the plug hole H while the plug cap PC for the internal combustion engine is inserted. With the plug cord C attached, the internal combustion engine plug cap PC is lowered. Then, as shown in Figure 12,
The chevron projection 53 of the engaging piece 52 contacts the uppermost end point of the step portion 51. When the internal combustion engine plug cap PC is further lowered in this state, as shown in FIG. 13, the engaging piece 52 is elastically deformed in the outward direction (D1 direction), and the chevron projection 53 causes the step portion 5 to move.
Descent over the 1st mountain. In this way, the internal combustion engine plug cap PC is lowered while repeating the elastic deformation of the engaging piece 52 by the number of peaks of the step portion 51, and the chevron projection 53 is formed in the valley portion at a predetermined position of the step portion 51 as shown in FIG. Engage. Then, even if the rain cover 20 tries to separate upward, such separation is prevented.

At this time, since the O-ring 55 is pressed downward by the top surface 57 of the groove 28a of the skirt 28, the groove 2
8a top surface 57 and O ring 55 and O ring 55 and collar 2
The upper surface of 9 is in close contact with each other, and thus the plug hole H is kept watertight.

When it is determined that the O-ring 55 has changed its shape due to aging and its waterproofness is deteriorated, the rain cover 20 is pushed further in, and the chevron projection 53 of the engaging piece 52 is further lowered below the step portion 51. If it is engaged with the side, it is possible to obtain the waterproof sealability similar to or better than the initial state. In this way, the adhesion of the O-ring 55 can be adjusted by advancing and retracting the rain cover 20, so that even if the O-ring 55 deteriorates over time due to long-term use, it is possible to prevent the deterioration of waterproofness, prevent the internal combustion engine from starting poorly, and run. It is possible to prevent the occurrence of poor properties.

{Modification} In the second and third embodiments, the elastic pressing body 43 is adopted as the sealing means for keeping the inside of the plug hole H in a watertight state, but the connecting portion 43a or the lower surface of the skirt 28 is used. Alternatively, a protrusion 34 similar to that of the first embodiment may be formed on the upper surface (sandwiched position) of the collar 29. In this case, the rain cover 20 is plugged into the plug hole H by screwing the first screw portion 41 and the second screw portion 42 together.
By allowing the ridge 34 to move back and forth, the adhesion of the ridge 34 can be adjusted, and therefore, the aging deterioration of the ridge 34 can be easily dealt with.

Also in the fourth embodiment, instead of the O-ring 55, a protrusion 34 similar to that of the first embodiment is formed on the lower surface of the skirt 28 or the upper surface (sandwich position) of the collar 29 as the sealing means. You may. In this case, the rain cover 20 can be moved forward and backward with respect to the plug hole H by screwing the stepped portion 51 and the chevron projection 53, so that the adhesion of the ridge 34 can be adjusted, and thus the ridge 34 is easily deteriorated over time. Can handle.

Further, in the fourth embodiment, as the engaging means for detachably engaging the elastic synthetic resin rain cover 20 with the flange 29 of the plug hole H, the same step as in the third embodiment is used. Although the portion 51 and the engagement piece 52 are applied, instead of such a configuration, the first embodiment similar to the second embodiment is used.
By applying the screw portion 41 and the second screw portion 42 screwed to the screw portion 41, the forward / backward movement of the rain cover 20 with respect to the plug hole H can be adjusted steplessly, so that the pressing force against the O ring 55 can be adjusted steplessly. Therefore, the adhesion of the O-ring 55 can be adjusted more finely than in the fourth embodiment.

Furthermore, as shown in FIGS. 14 and 15,
The O-ring 55 may be engaged with the skirt 28 by the engaging claws 61, 63 and the engaging grooves 62, 64. In this case, after inserting the O-ring 55 into the skirt 28 in advance and engaging the predetermined engaging claws 61 and 63 with the engaging grooves 62 and 64, the skirt 28 is put over the collar of a plug hole (not shown) to form a chevron shape. The protrusion 53 may be engaged with the stepped portion of the collar.

Alternatively, an O-ring for sealing may be used in the first embodiment, or the rain cover may be formed separately, and the rain cover may be changed by combining with other embodiments or changing the product material. Of course, the integration and the plug cap may be integrated.

[0052]

According to the first to fifth aspects of the present invention, since the rain cover is detachably engaged with the opening portion of the plug hole by the engaging means, the plug cord is slightly inserted by the operator. Even when the plug cord is attached halfway or when the plug cord is hooked to the electric wire portion when the peripheral internal combustion engine auxiliary equipment is attached after the plug cord is attached, the rain cover is prevented from being detached from the plug hole. Therefore, the spark plug and the plug cord can be securely coupled,
It is possible to prevent misfire of the spark plug, poor starting of the internal combustion engine, poor running performance, and the like. Further, since the above engagement is possible without using a frictional force, the plug cord and the rain cover can be easily attached to and detached from the plug hole.

Further, according to the invention described in claims 6 to 9, the inside of the plug hole can be easily kept watertight by the sealing means provided separately from the engaging means. The engaging means having a simple and inexpensive structure can be applied without considering the sealing property of the joining means.

Further, in the inventions according to claims 7 to 9, the rain cover is movable back and forth with respect to the plug hole, and the sealing means is provided at a sandwiching position between the rain cover and the opening of the plug hole. Since it is arranged, the adhesion of the sealing means can be adjusted by moving the rain cover back and forth. Therefore, when it is determined that the sealing means has changed its shape due to aging and has deteriorated the waterproofness, the rain cover is advanced to the plug hole and the sandwiching force of the sealing means is increased, thereby lowering the waterproofness. Can be prevented,
As a result, it is possible to prevent the start-up of the internal combustion engine and the runnability from occurring.

[Brief description of drawings]

FIG. 1 is a sectional view showing a plug cap for an internal combustion engine and a peripheral mechanism thereof according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a plug cap mechanism for an internal combustion engine according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a plug cap mechanism for an internal combustion engine according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a plug cap mechanism for an internal combustion engine according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a plug cap mechanism for an internal combustion engine according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing a plug cap mechanism for an internal combustion engine according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a plug cap mechanism for an internal combustion engine according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the operation of attaching the internal combustion engine plug cap to the cylinder head of the internal combustion engine in the third embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the operation of attaching the internal combustion engine plug cap to the cylinder head of the internal combustion engine in the third embodiment of the present invention.

FIG. 10 is a sectional view showing a plug cap mechanism for an internal combustion engine according to a fourth embodiment of the present invention.

FIG. 11 is a perspective view showing a plug cap mechanism for an internal combustion engine according to a fourth embodiment of the present invention.

FIG. 12 is a cross-sectional view showing the operation of attaching the internal combustion engine plug cap to the cylinder head of the internal combustion engine in the fourth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing the operation of attaching the internal combustion engine plug cap to the cylinder head of the internal combustion engine in the fourth embodiment of the present invention.

FIG. 14 is a sectional view showing a skirt and an O-ring of a modified example of the invention.

FIG. 15 is a sectional view showing a skirt and an O-ring of another modification of the present invention.

FIG. 16 is a cross-sectional view showing a conventional internal combustion engine plug cap mechanism.

FIG. 17 is a perspective view showing a conventional internal combustion engine plug cap mechanism.

FIG. 18 is a cross-sectional view showing another conventional internal combustion engine plug cap mechanism.

[Explanation of symbols]

 10 Plug Cap Pipe 11 Pipe Main Body 12 Opening 16 Spark Plug 20 Rain Cover 21 Cover Main Body 22 Plug Hole Insertion Part 28 Skirt 28a Groove 29 Collar 31 Projection 32 Protrusion 33 Notch 34 Projection 41 First Screw 42 42 Second Screw portion 43 Elastic pressing body 51 Step portion 52 Engagement piece 55 O-ring C Plug cord H Plug hole PC Internal combustion engine plug cap

Claims (9)

[Claims] 1. A plug cap mechanism for an internal combustion engine, which closes an opening of the plug hole having a collar when the plug cord is inserted into the plug hole of the internal combustion engine, wherein the plug cord is inserted. And a plug cap pipe housed in the plug hole of the internal combustion engine, a skirt that is externally fitted to the upper end portion of the plug cap pipe and fitted to the flange of the plug hole, and is fitted into the plug hole. A rain cover having a plug hole insertion portion that closes the opening of the plug hole, and an engagement unit that detachably engages the rain cover with the opening of the plug hole. A first engaging element protruding outward from an outer peripheral surface of the plug hole insertion portion of the rain cover; and the collar of the plug hole. A plug cap mechanism for an internal combustion engine, comprising: a second engaging element that projects from the inside toward the inside and engages with the first engaging element. 2. The plug cap mechanism for an internal combustion engine according to claim 1, wherein a cutout for fitting the first engaging element is formed in the second engaging element. Internal combustion engine plug cap mechanism. 3. A plug cap mechanism for an internal combustion engine, which closes an opening of the plug hole having a collar when the plug cord is inserted into the plug hole of the internal combustion engine, wherein the plug cord is inserted. And a plug cap pipe housed in the plug hole of the internal combustion engine, a skirt that is externally fitted to the upper end portion of the plug cap pipe and fitted to the flange of the plug hole, and is fitted into the plug hole. A rain cover having a plug hole insertion portion that closes the opening of the plug hole, and a member that allows the rain cover to move back and forth with respect to the plug hole and detachably engage with the opening of the plug hole. And a first screw portion formed on the skirt of the rain cover, and the first screw portion. And a second screw portion formed on the flange of the plug hole so as to be screwed into the plug cap mechanism for an internal combustion engine. 4. A plug cap mechanism for an internal combustion engine, which closes an opening of the plug hole having a collar when the plug cord is inserted into the plug hole of the internal combustion engine, wherein the plug cord is inserted. And a plug cap pipe housed in the plug hole of the internal combustion engine, a skirt that is externally fitted to the upper end portion of the plug cap pipe and fitted to the flange of the plug hole, and is fitted into the plug hole. A rain cover having a plug hole insertion portion that closes the opening of the plug hole, and a member that allows the rain cover to move back and forth with respect to the plug hole and detachably engage with the opening of the plug hole. The engaging means is provided on one of the skirt of the rain cover and the brim of the plug hole. A step portion formed with a number of steps, and the skirt of the rain cover and the rain cover so as to engage with any step among a plurality of steps of the step portion to position the rain cover in the advancing / retreating direction. A plug cap mechanism for an internal combustion engine, comprising: an engagement piece formed on the other of the flanges of the plug hole. 5. The internal combustion engine plug cap mechanism according to claim 4, wherein the engagement piece is formed to have elasticity in a direction facing the step portion. Plug cap mechanism. 6. The plug cap mechanism for an internal combustion engine according to claim 1, claim 3, claim 4 or claim 5, further comprising a sealing means for holding the inside of the plug hole in a watertight manner, The plug cap mechanism for an internal combustion engine, wherein the sealing means is an elastic pressing body which is formed on at least one of the rain cover and the flange of the plug hole and is in close contact with the other surface. 7. The plug cap mechanism for an internal combustion engine according to claim 3, claim 4, or claim 5, wherein a sealing means for holding the inside of the plug hole in a watertight manner is provided, and the sealing means. Is disposed at a sandwiching position sandwiched between the inner surface of the skirt of the rain cover and the tip surface of the collar of the plug hole as the rain cover advances. . 8. The plug cap mechanism for an internal combustion engine according to claim 7, wherein the sealing means includes an inner surface of the skirt of the rain cover and a tip surface of the collar of the plug hole at the sandwiched position. A plug cap mechanism for an internal combustion engine, which is a ridge formed on at least one of them. 9. The plug cap mechanism for an internal combustion engine according to claim 6, wherein the sealing means is an O-ring inserted in the sandwiched position.