JPH059911B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for attaching a cover tube for an ignition plug screwed to a cylinder head so as to pass through a cylinder head cover that is detachably attached to the upper surface of the cylinder head. The present invention relates to a sealing device at a portion where the ignition plug cover pipe passes through the cylinder head cover in the internal combustion engine.

[Conventional technology]

In this way, when the cover tube for the ignition plug screwed onto the cylinder head is installed so as to pass through the cylinder head cover which is detachably attached to the upper surface of the cylinder head, the cover tube for the ignition plug is attached to the cylinder head cover. It is necessary to apply a seal to the part that passes through the cylinder head cover to prevent blow-by gas from leaking outside in the valve train chamber inside the cylinder head cover. Therefore, as prior art, JP-A-54-125315 and JP-A-53-
Publication No. 86908 discloses a seal ring member made of a soft elastic material having a rectangular cross section and inserted between the inner peripheral surface of a through hole for a cover pipe drilled in a cylinder head cover and a cover pipe for an ignition plug. I am proposing to do so.

[Problem to be solved by the invention]

However, the spark plug cover pipe is attached to the cylinder head, while the cylinder head cover is detachably attached to the top surface of the cylinder head. is installed separately to the cylinder head, and there is a gap between the axis of the spark plug cover tube and the axis of the through hole in the cylinder head cover due to dimensional errors during processing and backlash in the installation position. Due to such reasons, there is a fairly large positional shift.

Therefore, if the sealing member for this gap is a seal ring with a rectangular cross section inserted between the inner circumferential surface of the cover pipe through hole in the cylinder head cover and the spark plug cover pipe as in each of the above-mentioned prior arts,
Since the amount of elastic deformation of the seal ring is small and the above-mentioned positional deviation cannot be absorbed by the elastic deformation of the seal ring, it is necessary to attach the cylinder head cover to the cylinder head in the correct position. Not only is it difficult to attach the seal ring to the cylinder head, but after the cylinder head cover is attached to the cylinder head, there are some parts where the seal ring is too close to the cover tube, and some parts are poor, and the sealing performance is reduced in the parts where the seal ring is not in close contact. If the cylinder head cover is removed from the cylinder head, blow-by gas leakage will occur, and if the cylinder head cover is removed from the cylinder head, it will not only be damaged by strong rubbing against the cover pipe, but also vibration in the cylinder head cover and damage to the cover. The mutual transmission with vibrations in the tube was increased.

The present invention solves the problems of the prior art in sealing the portion where the spark plug cover tube passes through the cylinder head cover.

[Means to solve the problem]

In order to achieve this object, the present invention fixes a cover pipe for an ignition plug screwed to a cylinder head so as to pass through a cylinder head cover that is detachably attached to the upper surface of the cylinder head, In an internal combustion engine in which a seal ring made of a soft elastic material is inserted between the ignition plug cover tube and a through hole in the cylinder head cover, the seal ring is connected to the outer ring part and the inner ring part by an annular groove. The outer ring part is fitted into the through hole in the cylinder head cover so that the annular groove opens to the outside of the cylinder head cover, while the inner ring part is fitted into the spark plug cover tube, the seal ring is provided with an elastic ring body whose inner ring portion is squeezed against the spark plug cover tube, and the seal ring is further provided with an elastic ring body whose inner ring portion is squeezed against the spark plug cover tube. , a cover body covering the outside of the seal ring is detachably attached.

[Action/effect of the invention]

In this way, the seal ring is formed into a U-shaped cross section so that the outer ring part and the inner ring are formed by the annular groove, and the outer ring part is fitted into the through hole in the cylinder head cover, while the inner ring part is fitted into the through hole in the cylinder head cover. By fitting the seal ring into the cover tube for the spark plug, the amount of elastic deformation in this seal ring is larger than that of the square cross section of the prior art, and the axis of the cover tube and the axis of the through hole in the cylinder head cover are larger. Even if there is a large positional deviation between the cylinder head cover and the core due to dimensional errors during processing or play in the mounting position, this large positional deviation can be easily absorbed with a light force. The seal ring can be easily installed in the correct position on the cylinder head, and after the cylinder head cover is installed on the cylinder head, the seal ring can be prevented from being locally excessively close to the spark plug cover pipe. On the other hand, by squeezing the inner ring part of the U-shaped cross-sectional seal ring against the ignition plug cover pipe with an elastic ring body, the axial center of the cover pipe and the cylinder head cover can be prevented. This prevents the ignition plug cover tube from being in close contact with the ignition plug cover pipe locally or excessively due to misalignment with the axis of the through hole.

Therefore, according to the present invention, there is no misalignment between the axis of the spark plug cover tube that is fixed to the cylinder head and the axis of the through hole in the cylinder head cover that is detachably attached to the cylinder head. Due to the presence of the cylinder head cover, it is possible to reliably prevent the workability of installing the cylinder head cover to the cylinder head from being reduced and the sealing performance for the spark plug cover pipe from being reduced.
Mutual transmission of vibrations between the cylinder head cover and the cover pipe can be reliably reduced.

On the other hand, even if the seal ring is formed to have a U-shaped cross section, if the annular groove forming the U-shaped cross section opens inside the cylinder head cover, the seal ring may be While holding the inner ring part of the seal ring which is squeezed by the elastic ring body in an expanded state against the elastic force of the elastic ring body, insert it into the ignition plug cover pipe fixed to the cylinder head. Therefore, not only does it take a lot of effort to fit the spark plug cover tube, but also the inner ring body is damaged during this fitting.

In contrast, in the present invention, an annular groove is provided and the cross section U
A seal ring formed in the shape of a letter is fitted into a through hole in the cylinder head cover so that the annular groove opens to the outside of the cylinder head cover. When fitting the seal ring, there is no need to hold the inner ring part of the seal ring in an expanded state against the elasticity of the elastic ring body, and the seal ring can be fitted very easily by simply pushing it. This greatly improves the workability when fitting onto the plug cover pipe, and also prevents the seal ring from becoming locally excessively close to the spark plug cover pipe as described above. In combination with this, it is possible to reliably reduce damage to the seal ring that occurs when the cylinder head cover is attached to and removed from the cylinder head.

In addition, the present invention has a structure in which a cover body that covers the outside of the seal ring is detachably attached to the cover tube for the early spark plug, so that the seal ring has an annular shape that opens to the outside of the cylinder head cover. The cover body can prevent dust, water, etc. from entering the groove,
In other words, since dust, water, etc. can be prevented from accumulating in the annular groove, deterioration of the seal ring due to accumulation of dust, water, etc. in the annular groove can be prevented, and its durability can be improved. The accumulation of dust, water, etc. in the annular groove also has the effect of preventing dust, water, etc. from falling onto the valve mechanism on the upper surface of the cylinder head when the cylinder head cover is removed from the cylinder head.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates a cylinder block in an internal combustion engine, reference numeral 2 indicates a cylinder head fastened to the upper surface of the cylinder block 1, and reference numeral 3 indicates a cylinder head fastened to the upper surface of the cylinder block 1.
1 and 2 respectively show cylinder head covers that are detachably attached to the upper surface of the cylinder head 2, and the valve mechanism chamber 4 in the cylinder head cover 3 has a camshaft 7 and a rocker arm 8 for the intake valve 5 and the exhaust valve 6, respectively. A valve mechanism 10 such as 9 is provided.

Reference numeral 11 indicates that the electrode portion 11a at the tip is connected to the combustion chamber 12.
The ignition plug is screwed onto the cylinder head 2 so that the ignition plug 12 faces the ignition plug 12. Reference numeral 13 indicates a cover pipe for the ignition plug 12, and the cover pipe 13 is arranged at an appropriate angle ( The upper end of the spark plug cover tube 13 is connected to the cylinder head cover 3 through the through hole 3a bored in the cylinder head cover 3. protruding outside.

Reference numeral 15 indicates a seal ring inserted between the through hole 3a and the spark plug cover tube 12, and the seal ring 15 is made of a soft elastic material such as heat-resistant rubber and is formed into an annular groove 15c. The outer ring 15a and the inner ring portion 15b are formed into a U-shaped cross section, and the outer ring 15a
is reinforced with a ring body 16 made of a metal plate and inserted into the through hole 3a so that the annular groove 15c opens to the outside of the cylinder head cover 3, while the inner ring part 15b is inserted into the cylinder head cover 3. As shown in FIG. 3, an elastic ring body 17 made of two turns of steel wire is provided on the outer periphery of the inner ring portion 15b and fitted into the stopper cover tube 12. The ring body 17 is configured to narrow the inner ring portion 15b toward the spark plug cover tube 12.

Furthermore, at the tip of the spark plug cover tube 13,
A cover body 19 made of a soft elastic material that covers the outside of the seal ring 15 is configured to be detachably attached.

In this way, the seal ring 15 is inserted into the annular groove 15c.
The outer ring portion 15a and the inner ring portion 15 are
By forming the outer ring portion 15b into a U-shaped cross section so as to form the outer ring portion 15b, the outer ring portion 15b is largely elastically deformed in a direction perpendicular to the axis of the seal ring 15 when it is fitted into the spark plug cover tube 12. Therefore, there is a large misalignment between the axial center of the spark plug cover tube 12 and the axial center of the through hole 3a in the cylinder head cover 3 due to dimensional errors during processing and play in the mounting position. However, since the inner ring portion 15b is squeezed against the cover tube 12 by the elastic ring body 17, the outer ring 15b can easily follow this large displacement. Even if the seal ring 15 undergoes large elastic deformation in the direction perpendicular to the axis of the seal ring 15 while fitted onto the pipe 12, the cover pipe 1
The close bond to 2 will never loosen.

In the seal ring 15, an annular groove 15c is formed to form a U-shaped cross section.
By configuring the cylinder head cover 3 to be open to the outside, when fitting the seal ring 15 to the spark plug cover pipe 13, the inner ring portion 15b of the seal ring 15 is inserted into the elastic ring body 17. There is no longer a need to hold it in an expanded state against elasticity.

On the other hand, a cover body 19 made of a soft elastic material that covers the outside of the seal ring 15 is detachably attached to the tip of the spark plug cover tube 13, so that the annular groove 15c in the seal ring 15 is removably attached.
Since the cylinder head cover 3 is configured to open to the outside of the cylinder head cover 3, the cover body 19 reliably prevents atmospheric dust, water, etc. from accumulating in the annular groove 15c. This is possible.

Note that the elastic ring body 17 may be constructed by winding a coil spring into a ring shape instead of the steel wire wound twice as in the above embodiment. On the inner peripheral surface of the portion 15b,
If the protrusion 18 is provided as shown in FIG. 2, the sealing performance will be further improved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view showing the main parts of an internal combustion engine, FIG. 2 is an enlarged view of the seal ring in FIG. 1, and FIG. 3 is a perspective view of an elastic ring body. be. DESCRIPTION OF SYMBOLS 1...Cylinder block, 2...Cylinder head, 3...Cylinder head cover, 11...Ignition plug, 12...Ignition plug cover pipe, 3a...Through hole, 15...Seal ring, 15a...Outside Ring part, 15b... Inner ring part, 15c... Annular groove, 17... Elastic ring body, 19... Cover body.

Claims (1)

[Claims] 1. A cover pipe for an ignition plug screwed onto a cylinder head is fixed to the cylinder head so as to pass through a cylinder head cover that is removably attached to the upper surface of the cylinder head, and the cover pipe for the ignition plug and the cylinder In an internal combustion engine in which a seal ring made of a soft elastic material is inserted between a through hole in a head cover, the seal ring has a cross section U such that an outer ring portion and an inner ring portion are formed by an annular groove. The outer ring part is fitted into the through hole in the cylinder head cover so that the annular groove opens to the outside of the cylinder head cover, while the inner ring part is fitted over the spark plug cover pipe. The seal ring is fitted with an elastic ring body whose inner ring portion is squeezed against the spark plug cover pipe, and the spark plug cover pipe is further provided with a cover that covers the outside of the seal ring. A sealing device for a cover pipe for a spark plug in an internal combustion engine, characterized in that the body is detachably attached.