JPS61123746A - Sealing device of ignition plug insertion hole - Google Patents

Abstract

PURPOSE:To facilitate the assembling work by forming the ignition plug insertion hole for fixing an ignition plug through cylinder head cover to the cylinder head with pipe member while fitting specific sealing member at the end of said pipe member. CONSTITUTION:A pipe fitting hole 9 is made at the upper end of ignition plug mounting hole 8 formed approximately in vertical direction through head block 1a and cam case 1b constituting a cylinder head 1. While a pipe fitting hole 12 is formed at the lower portion of an opening 11 for matching the mounting hole 8 of head cover 2. Then a pipe member 10 is fixed while fitting the opposite ends to both pipe fitting holes 9, 12. Here, the pipe member 10 is provided with an enlarged engaging section 10c at the upper end section while flange sections 10a, 10b are projected radially outward from the vicinity of the opposite end sections. Then an annular sealing body 14 and an O-ring 13 engagable with the engaging section 10c are fitted respectively to the upper and lower end sections of the pipe member 10.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a structure of a spark plug insertion hole for inserting an engine spark plug through an opening provided in a cylinder head cover and attaching it to the cylinder head. In particular, such a spark plug insertion hole should be made of a separate pipe member, and a sealing member provided between the pipe member and the cylinder head and cylinder head cover should ensure that the inside of the head cover and the spark plug insertion hole are connected. The present invention relates to a sealing device for a spark plug insertion hole, which seals the space between the spark plug insertion holes.

<Prior Art> In an internal combustion engine, the spark plug of the engine is preferably attached to the center of the cylinder head so that combustion starts from the center of the combustion chamber. For this purpose, some engines have an opening in the cylinder head cover through which the spark plug can be inserted and installed. However, in the space surrounded by the cylinder head and head cover, that is, in the locker room, the valve mechanism etc. are located.
It is also full of blow-by gas. Therefore, in order to install the spark plug by penetrating the head cover, it is necessary to seal the insertion hole from the surroundings.

Therefore, in the past, a wall forming the spark plug insertion hole was provided integrally with the cylinder head, and a sealing member attached to the upper end of the wall was brought into close contact with the lower surface of the head cover to seal the locker room from the spark plug insertion hole. Was. However, it is necessary to ensure a sealing surface on the upper end of the wall, so the wall thickness must be increased to a certain extent, and for this reason, the valve mechanism and tightening that are densely arranged in the locker room are bolted. This imposes restrictions on the layout of the engine, which not only hinders miniaturization of the engine but also increases its weight.

Therefore, the wall that forms the spark plug insertion hole is made of a separate pipe member, and both ends of the pipe member are fitted into pipe fitting holes formed in the cylinder head and head cover, and a sealing member is used between them. proposed to seal it. If such a pipe member is used, its wall thickness can be reduced, which increases the degree of freedom in layout of the valve mechanism, etc., and makes it possible to reduce the size and weight of the entire pipe member. However, such a seal for a pipe member is normally achieved by fitting a sealing member such as an O-ring around the outer periphery of the pipe member.

This is done by closely contacting the inner circumferential surfaces of the pipe fitting holes in the cylinder head and head cover, so in order to obtain the desired sealing effect, the outer diameter of the sealing member in its natural state should be It must be slightly larger than the inner diameter of the matching hole. Therefore, when assembling the pipe member with such a seal member attached to the cylinder head and head cover,
It is necessary to accurately align the pipe member and head cover.

However, it is unavoidable that variations in the diameter, position, etc. of pipe fitting holes in such pipe members, cylinder heads, or head covers occur due to processing. Furthermore, in a multi-cylinder engine, when assembling the head cover to the cylinder head, it is necessary to assemble multiple pipe members provided for each cylinder at the same time, and these pipe members, the cylinder head, or the pipe fitting hole of the head cover must be assembled at the same time. Any variation in position or size between them will make their assembly very difficult. Furthermore, if such uneven pipe members are forcibly assembled, the pipe axis will be eccentric, and the seal member may be affected by the eccentricity and may not be able to exhibit the desired sealing effect.

Therefore, Utility Application No. 58-150゜464 filed by the same applicant.
No. (Utility Model Publication No.), a flange is provided at least on the - end of the pipe member, and the flange is fitted into the pipe fitting hole into which the end on the flange side is fitted. Opposing shoulders are provided, and when the pipe member, the cylinder head, and the head cover are assembled, the seal member has both end surfaces in the axial direction in close contact with the flange and the shoulder, respectively, and there is a space between them. and has an outer diameter smaller than the inner diameter of the pipe fitting hole or an inner diameter larger than the outer diameter of the pipe member, at least before they are assembled. A sealing device for a spark plug insertion hole in an engine is disclosed. According to this sealing device, the above-mentioned drawbacks are eliminated, but the sealing member may fall off from the pipe member or the pipe fitting hole, and the handling of the sealing member during assembly or disassembly may be difficult. There are issues that require attention.

<Problems to be Solved by the Invention> In view of these drawbacks of the prior art, the main object of the present invention is to provide a seal for the insertion hole of a spark plug in an engine that eliminates the above drawbacks and is easy to disassemble or assemble. The goal is to provide equipment.

Means for Solving the Problems> According to the present invention, a pipe fitting hole formed in a cylinder head and a cylinder head cover, and a pipe fitting hole to be fitted into the pipe fitting hole are In the sealing device for a spark plug insertion hole of an engine, the sealing device includes a pipe member having both ends, and an annular seal member sandwiched between the pipe fitting hole and each end of the pipe member. At least one end of the pipe member is provided with an engaging portion and a shoulder portion adjacent to the engaging portion inwardly and having a surface facing outward in the axial direction, into which the end portion is fitted. A corresponding shoulder portion opposite to the shoulder portion is provided in the pipe fitting hole, and an inward protrusion that is to be elastically engaged with the retaining portion of the pipe member is provided on the inner circumferential surface of the annular seal. A sealing device for a spark plug insertion hole of an engine is provided, wherein at least one end of the pipe member is provided with a shoulder facing outward in the axial direction,
The pipe fitting hole into which the end portion is fitted is provided with a corresponding shoulder portion opposite to the shoulder portion and a circumferential groove provided at an intermediate position between the two shoulder portions, and the outer circumference of the annular seal is This is achieved by providing a sealing device for a spark plug insertion hole of an engine, the surface of which is provided with an outward protrusion that resiliently engages with the circumferential groove. In particular, it is preferable to provide the inward protrusions at the upper and lower ends of the inner circumferential surface of the annular seal.

<Function> By allowing the seal member and the pipe member or the pipe fitting hole to engage elastically with each other in this way, the seal member is extremely difficult to fall off, so the assembly of the seal structure is easy. Alternatively, the ease of handling the seal member during disassembly is significantly improved.

Furthermore, if the inward protrusions are provided at the upper and lower ends of the inner circumferential surface of the annular seal, the annular seal can be used equally even if it is turned upside down, and its handling is improved, and the protrusions on the lower end side are Since the inward protrusion on the upper end side projects onto the upper end surface of the pipe member while engaging with the engaging portion of the pipe member, direct contact between the head cover and the pipe member can be avoided.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 shows a longitudinal section of a cylinder head portion of an engine equipped with a sealing device for a spark plug insertion hole according to the present invention. The cylinder head 1 consists of a head block 1a and a cam case 1b assembled on the upper surface of the head block 1a, but these may be integrated. A cylinder head cover 2 is attached to the upper surface of the cam case 1b via a gasket, and a locker room 3 is defined by the cam case 1b and the head cover 2. Inside the locker room 3, valve mechanisms such as a camshaft 4, a rocker arm (not shown), a pulp spring (not shown), and a large number of fastening bolts 5 are arranged closely.

A spark plug 6 is screwed onto the cylinder head 1.
The discharge electrode 6a projects into the center of the upper part of the combustion chamber 7 from above. A substantially vertical spark plug mounting hole 8 is formed in the center of the head block 1a and the cam case 1b. A pipe fitting hole 9 is formed at the upper end of the spark plug mounting hole 8, and the lower end of the pipe portion 1/A10 is fitted into the pipe fitting hole 9. On the other hand, the head force bar 2 is formed with an opening 11 that matches the spark plug mounting hole 8 of the cylinder head 1, and a second pipe fitting hole 12 is provided at the bottom of this opening 11. The upper end of the pipe member 10 is fitted into the hole 12 . In this way, without removing the head cover 2,
From above the head cover 2, the opening 11, the pipe member 10,
The spark plug 6 can be attached and detached through the spark plug mounting hole 8.

As shown in an enlarged view in FIG. 2, an engaging part 10c formed by expanding the pipe member is formed at the uppermost end of the pipe member 10, and a collar part 10a protruding radially outward at the lower part thereof.
is formed. Further, near the lower end of the pipe member 10, a flange portion 10b that similarly projects outward in the radial direction is formed.

Now, the lowermost end of the pipe member 10 is fitted relatively tightly into the small diameter part 9b of the pipe fitting hole 9, and the flange part 10b protrudes into the large diameter part 9a of the pipe fitting hole 9, and the elastomer material An O-ring 13 is inserted between the outer circumferential surface of the pipe member 10 and the inner circumferential surface of the large diameter portion 9a of the pipe fitting hole 9, or between the a section 10b.
and a shoulder portion 9C formed between the large diameter portion 19a and the small diameter portion 9b.
is sandwiched between. An annular seal member 14 made of an elastomer material is fitted into the upper end of the pipe member 10. As clearly shown in FIG. 3, annular protrusions 15 are provided on the upper and lower sides of the inner peripheral surface of the seal member 14 to project inward. Therefore, the inner circumferential surface of the annular seal member 14 and the outer circumferential surface of the upper end of the pipe member 10 have substantially complementary shapes to each other, but the inner diameter of the annular seal member 14 in its natural state is the same as that of the pipe member 10. Since the outer diameter is slightly smaller than the outer diameter of the upper end, the lower protrusion 15 of the seal member 14 elastically engages with the engagement portion 10c at the upper end of the pipe member 10, and the bottom surface of the seal member 14 The shoulder portion of the pipe member 10, that is, the collar portion 10
It comes into contact with the upper surface of a.

According to this embodiment, the O-ring 13 is fitted to the lower end of the pipe member 10, and the lower end is connected to the small diameter portion 9b of the pipe fitting hole 9.
When fitted, the O-ring 13 is inserted between the outer circumferential surface of the pipe member 10 and the inner circumferential surface of the large diameter portion 9a of the pipe fitting hole 9, or between the lower surface of the collar 1s10b and the shoulder portion 9G of the pipe fitting hole 9. is compressed between the inside of the pipe member 10 and the locker room 3.
A seal is achieved between the

Furthermore, when the seal member 14 is fitted to the upper end of the pipe member 10, the outer diameter of the seal member 14 is smaller than the inner diameter of the upper pipe fitting hole 12, and a space jlr is formed between them, so that the pipe member 10 is slightly inclined, or the head cover 2
Even if the position of the pipe member 10 is slightly shifted, the seal member 14, that is, the upper end of the pipe member 10 can be inserted into the pipe fitting hole 12. Next, when the mounting bolts (not shown) of the head cover 2 are tightened, the head cover 2 is displaced downward, and the seal member 14 is inserted into the shoulder portion 1 of the pipe fitting hole 12.
2a and the upper surface of the flange 10a of the pipe member 10, thereby achieving the same desired sealing effect.

In particular, since the annular protrusions 15 are provided at the upper and lower ends of the inner circumferential surface of the seal member 14, the seal member 10a can be equally used even if it is turned upside down, and its handling is good. Since the protrusion engages with the engaging portion 10c and the protrusion on the upper end side protrudes onto the upper end surface of the pipe member 10, the head cover 2 and the upper end of the pipe member 10 do not come into direct contact when attaching the head cover 2. Therefore, it is possible to achieve effects such as ensuring the sealing effect.

In the embodiment shown in FIGS. 1 and 2, even when the seal member 14 is compressed and deformed, there is a gap in the radial direction between its outer periphery and the inner periphery of the pipe fitting hole 12. However, if the outer diameter of the seal member 14 is sufficiently smaller than the inner diameter of the pipe fitting hole 12 before the head cover 2 is assembled, assembly and attachment will not necessarily be performed later. ti+mr does not have to be formed.

The fourth factor shows another embodiment of the seal structure at the upper end of the pipe member 10. In this embodiment, as shown in FIG. 5, annular protrusions 15' are provided on the upper and lower sides of the outer circumferential surface of the annular seal member 14' to protrude downward. An annular groove 12b is recessed in the inner peripheral surface of the pipe fitting hole 12 adjacent to the shoulder portion 12a. Therefore, the inner circumferential surface of the pipe fitting hole 12 and the outer circumferential surface of the annular seal member 14' have substantially complementary shapes, but in a natural state, the outer diameter of the annular seal member 14' 12, so when the annular seal member 14' is fitted into the pipe fitting hole 12, the elastic force of the annular seal member 14' causes the seal member 14'
will be held relatively firmly. In this embodiment, the upper end of the pipe member 10 and the annular seal member 14'
Since a gap r' is formed between the pipe member 10 and the inner circumferential surface of the pipe member 10, even if the pipe member 10 is slightly inclined or the position of the head cover 2 is slightly deviated, the pipe member 10 is The upper end portion can be inserted into the pipe fitting hole 12 relatively easily.

Next, when attaching the head cover 2 (not shown), when bolts are tightened, the entire head cover 2 is displaced downward and the annular seal member 14' is compressed between the shoulder part 14' of the head cover and the collar part 10a of the pipe member 10. It will be done. At this time, a gap r' is formed between the outer peripheral surface of the pipe member 10 and the inner peripheral surface of the annular seal member 14'. It is sufficient that the gap r' is sufficiently smaller than the outer diameter of the upper end of the pipe member 10, and such a gap r' does not necessarily have to be formed during assembly.

FIG. 6 shows still another embodiment of the seal structure according to the present invention, and the seal structure between the pipe member 10 and the head cover 2 is exactly the same as the embodiment described above with reference to FIGS. 1 and 2. However, a step 10G is provided near the lower end of the pipe member 10 instead of the flange 10b,
Further, its lower end portion forms a small diameter portion 10d.

Therefore, the small diameter portion 9b of the pipe fitting hole 9 has this small diameter portion 1.
0d is fitted, and the O-ring 13 is fitted between the outer peripheral surface of the small diameter portion 10d of the pipe member 10 and the inner peripheral surface of the large diameter portion 9a of the pipe fitting hole 9, or the pipe is fitted with the downward facing surface of the step of the pipe member 10C. By being sandwiched between the shoulder portion 9C of the matching hole 9,
A seal between the inside of the pipe member 10 and the locker room 3 is achieved at the lower end of the pipe member 10.

In the case of this embodiment as well, the small diameter portion 10d of the pipe member 10 is
After fitting the ring 13 and the annular seal member 14 to the upper end of the pipe member 10, and fitting the small diameter portion 10d of the pipe member 10 into the small diameter portion 9b of the pipe fitting hole 9, the opening 11 of the head cover 2 is closed to the pipe. If the head cover 2 is attached so as to be substantially aligned with the member 10, the annular seal member 14 will enter the pipe fitting hole 12 on the head cover 2 side together with the upper end of the pipe member 10, and the head cover 2 can be attached by tightening bolts. Then the shoulder 12a of the pipe fitting hole 12
The annular seal member 14 is compressed between the upper surface of the collar W10a of the pipe member 10, and a seal between the inside of the pipe member 10 and the locker room 3 is achieved.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above. For example, it is also possible to provide a step 10G on the upper end side of the pipe member 10 in place of the flange portion 10a. Furthermore, the engagement structure between the annular seal member 14.14' and the upper end of the pipe member 10 or the pipe fitting hole 12 is not limited to the above, but may be any structure that can stably hold the annular seal member 14.14'. For example, they are equally applicable to the present invention.

Effects> As described above, according to the present invention, the spark plug insertion hole for installing the spark plug in the cylinder head through the radial cover into the cylinder is constituted by a separate pipe member. The head portion can be made smaller and lighter. In addition, the annular seal member that seals between the pipe member and the pipe fitting hole into which it is fitted has radial play, making assembly extremely easy. It is possible to increase the tolerance for errors in machining such as pipe fitting holes.

In addition, since the annular seal member is securely held in the pipe fitting hole or pipe member, the annular seal member will not fall off or be lost during disassembly and assembly, which greatly improves work efficiency. Improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a cylinder head portion of an engine to which an embodiment of a sealing device for a spark plug insertion hole according to the present invention is applied. FIG. 2 is an enlarged longitudinal sectional view of the main part of FIG. 1. FIG. 3 is an enlarged vertical sectional view of the annular seal member used in the embodiment shown in FIGS. 1 and 2. FIG. FIG. 4 is a partial vertical sectional view showing another embodiment of the seal structure at the upper end of the vibrator member. FIG. 5 is an enlarged vertical cross-sectional view of the annular seal member used in FIG. 4. FIG. 6 is a longitudinal sectional view showing another embodiment of the seal structure at the lower end of the vibrator member. 1... Cylinder head 2... Cylinder head cover 3... Locker room 4... Camshaft 5... Bolt 6... Spark plug 6a... Discharge electrode 7... Combustion chamber 8...・Spark plug mounting hole 9...
- Vibrator fitting hole 9a... Large diameter part 9b... Small diameter part 9C... Shoulder part 10... Vibrator member 1
0a, 10b... Flange 10 G-... Step 10d...
・Small diameter portion 11...Opening 12-...Pipe fitting hole 12 a-...Shoulder portion 13...0 ring 14.14'...Annular seal member 15.15'...Protrusion patent Applicant: Honda Motor Co., Ltd.
Attorney Patent Attorney Yo Oshima
-Figure 1 Figure 2WJ Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) A pipe fitting hole formed in the cylinder head and the cylinder head cover, a pipe member having both ends to be fitted into the pipe fitting hole, and the pipe fitting hole and each end of the pipe member. In a sealing device for a spark plug insertion hole of an engine, the sealing device has an annular sealing member sandwiched between the pipe member and the engaging part at least one end of the pipe member. a shoulder portion adjacent to the inside and having a surface facing outward in the axial direction; and a corresponding shoulder portion facing the shoulder portion is provided in the pipe fitting hole into which the end portion is fitted. A sealing device for a spark plug insertion hole of an engine, characterized in that an inward protrusion is provided on the inner circumferential surface of the annular seal to resiliently engage with the engaging portion of the pipe member. (2) The sealing device for a spark plug insertion hole of an engine according to claim 1, wherein the inward protrusions are provided at the upper and lower ends of the inner circumferential surface of the annular seal, respectively. (3) A pipe fitting hole formed in the cylinder head and the cylinder head cover, a pipe member having both ends to be fitted into the pipe fitting hole, and the pipe fitting hole and each end of the pipe member. In the sealing device for a spark plug insertion hole of an engine, the sealing device has an annular sealing member sandwiched between the pipe member and the pipe member, wherein at least one end of the pipe member is provided with a shoulder facing outward in the axial direction. The pipe fitting hole into which the end portion is fitted is provided with a corresponding shoulder portion opposite to the shoulder portion and a circumferential groove provided at an intermediate position between the two shoulder portions. 1. A sealing device for a spark plug insertion hole of an engine, characterized in that an outer circumferential surface of the seal is provided with an outward protrusion that elastically engages with the circumferential groove.