JP2001295931A - Cylinder head gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously provide excellent sealing performance with a primary seal part X and a secondary seal part Y. SOLUTION: This gasket 1 is provided with a first gasket base 2 and a second gasket base 3 overlapping each other. A grommet part 11 surrounding a combustion chamber hole is formed at the second gasket base, and an annular member is interposed inside the grommet part. The thickness t0 of the whole grommet part is set to be larger than the sum of the thickness t1 of the first gasket base and the thickness t2 of the second gasket base, and the thickness of both gasket bases are set to be same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head gasket used for an engine, and more particularly to a cylinder head gasket formed by laminating a plurality of substrates.

[0002]

2. Description of the Related Art Conventionally, as a cylinder head gasket, a first gasket substrate having a through-hole formed in accordance with a cylinder bore and a bead surrounding the through-hole, and the first gasket substrate are superimposed on the first gasket substrate to form a cylinder bore. And a bead portion formed so as to surround the through hole and a grommet portion formed by folding an edge of the through hole toward the first gasket substrate. A gasket substrate,
It is known that a tip of a grommet portion of the second gasket substrate is opposed to an edge of a through hole of the first gasket substrate, and a hole formed on an inner side of the grommet portion is formed as a combustion chamber hole. (For example, Shokai 6
In this type of cylinder head gasket, a primary seal portion surrounding the combustion chamber hole and having a locally increased surface pressure is formed on an extension of the grommet portion. On the other hand, a secondary seal portion surrounding the combustion chamber hole and having a locally high surface pressure is formed on an extension of both the bead portions on the outer side of this.

[0003]

In the above-mentioned publication, the folded portion of the grommet portion is overlapped with the non-folded portion, but the operation of forming such a grommet portion is complicated and not easy. Thus, strong stress acts on the bent portion of the grommet portion.
In the above publication, the thickness of the first gasket substrate is set to be smaller than the thickness of the second gasket substrate, and the size of the grommet portion is set to be larger than the sum of the thicknesses of the two gasket substrates. Although it is necessary, it is difficult to obtain good sealing properties at the primary seal part and the secondary seal part at the same time. That is, when the difference between the thickness of the first gasket substrate and the thickness of the second gasket substrate is reduced, the difference between the thickness of the grommet portion and the total thickness of both gasket substrates is small. As a result, the seal surface pressure in the primary seal portion is weakened. In contrast, the first
When the difference between the thickness of the gasket substrate and the thickness of the second gasket substrate is increased, the rigidity of the bead portion of the first gasket substrate decreases, so that the sealing surface pressure in the secondary seal portion decreases. . That is, it was difficult to simultaneously satisfy the thickness required for the grommet portion and the thickness required for the first gasket substrate and / or the second gasket substrate. In view of such circumstances, the present invention provides a cylinder head gasket that is easier to manufacture as compared with the related art, and that can obtain good sealing performance at both the primary seal portion and the secondary seal portion. Things.

[0004]

That is, the present invention provides a cylinder head gasket having the same structure as a conventional cylinder head gasket, wherein an annular member is interposed inside the grommet portion of the second gasket substrate.
When the thickness of the entire grommet portion in the state where the annular member is interposed is t0, the thickness of the first gasket substrate is t1, and the thickness of the second gasket substrate is t2, the first gasket is The thickness t1 of the substrate is equal to or greater than the thickness t2 of the second gasket substrate, and the thickness t0 of the entire grommet portion is adjusted to the thickness t1 of the first gasket substrate and the thickness t2 of the second gasket substrate. Are set to dimensions larger than the sum of the above.

[0005] According to such a configuration, since the annular member is interposed inside the grommet portion, the grommet portion can be folded back more gradually than in the conventional case, so that the grommet portion can be easily folded. Can be reduced. Further, the annular member interposed inside the grommet portion allows the thickness t0 of the entire grommet portion and the thickness t0 of the first gasket substrate to be increased.
Since the thickness t2 of the first and / or second gasket substrate can be set to a thickness satisfying the respective requirements, 1
Good sealing properties can be obtained with both the seal portion and the secondary seal portion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a cylinder head gasket 1 for an in-line four-cylinder engine will be described below. 1 and 2, a cylinder head gasket 1 includes a first gasket substrate 2 located on a cylinder head side (not shown) and a second gasket substrate superimposed on the first gasket substrate 2 and located on a cylinder block side (not shown). 3 and the first gasket substrate 2 and the second gasket substrate 3. The two gasket substrates 2 and 3 are set to have the same thickness and are integrally connected by, for example, a lance lock. The cylinder head gasket 1 is interposed between a cylinder head (not shown) and a cylinder block (not shown) as is well known in the art. It is designed to seal the gap. As shown in FIG. 1, the two gasket substrates 2 and 3 are provided with four combustion chamber holes 4 (only two are shown on the right side) drilled in accordance with the cylinder bores of an engine (not shown). The first, which surrounds and overlaps each other,
Second full bead portions 5 and 6, bolt holes 7 through which fastening bolts (not shown) pass, and water holes 8 through which cooling water flows
And are respectively formed.

As shown in FIG. 2, the first full bead portion 5 formed on the first gasket substrate 2 projects toward the second gasket substrate 3 while the second gasket substrate 3
The second full bead portions 6 formed on the first gasket substrate 2 side project from the first gasket substrate 2 side.
6 is formed vertically and symmetrically, and its vertex portion 5
a and 6a are butted against each other. In the second gasket substrate 3, an edge of a through hole (not shown) formed concentrically with the cylinder bore is turned toward the outside in the radial direction, and the tip thereof is bent through the through hole 10 of the first gasket substrate 2. The grommet 11 is provided with a grommet portion 11 opposed to the edge 10a of the grommet at a predetermined interval. The hole formed on the inner side of the grommet portion 11 is the combustion chamber hole 4 and the grommet portion 11 An annular member 13 described in detail later is interposed on the inside. The annular member 13 is made of a highly rigid metal material, and has a horizontally long rectangular cross section. The inner peripheral surface of the annular member 13 approaches the bent portion 11c of the grommet portion 11 and the outer peripheral surface thereof. Are located on the inner side than the folded portion 11b. In the state before assembling, there is a slight gap between the grommet portion 11 and the annular member 13, but this gap is within an allowable range of an error, and the grommet portion 11 and the annular member 13 are brought into contact in advance. It does not change.

In the above structure, the cylinder gasket 1 is interposed between the cylinder block and the cylinder head. In this state, the cylinder block and the cylinder head are integrally fastened by fastening bolts to seal the space therebetween. I do. Thereby, the grommet part 11
The non-folded portion 11a, the folded portion 11b, and the annular member 13 are vertically compressed (not shown) in the drawing (not shown), and the first full bead portion 5 and the second full bead portion 6 on the outer side are vertically (Not shown), thereby forming a primary seal portion X surrounding the combustion chamber hole 4 on an extension of the grommet portion 11, and also forming both full beads on the outer side of the primary seal portion X. A secondary seal portion Y surrounding the combustion chamber hole 4 is formed on an extension of the portions 5 and 6. At this time, the thickness t0 of the entire grommet portion 11 forming the primary seal portion X is the first gasket substrate 2
Is thicker than the sum of the thickness t1 of the second gasket substrate 3 and the thickness t2 of the second gasket substrate 3 by the thickness of the annular member 13, so that the sealing surface pressure in the primary seal portion X is sufficiently ensured. Good sealing properties can be obtained, and the thickness t1 of both full bead portions 5, 6 forming the secondary seal portion Y can be improved.
Since t2 is the same, it is possible to sufficiently secure the sealing surface pressure in the secondary sealing portion Y and obtain good sealing performance. By the way, since the secondary seal portion Y is doubled by the hem portions 5b and 6b of the full bead portions 5 and 6 being pressed against the cylinder head and the cylinder block, the hem portions are abutted with each other and the apex portion is formed. Good sealing performance can be obtained as compared with a structure in which the cylinder head is pressed against the cylinder head and the cylinder block.

Therefore, according to the cylinder head gasket 1, since the folded portion becomes looser as compared with the conventional case where the folded portion and the non-folded portion of the grommet portion are overlapped, the molding becomes easy and the grommet portion 11 is formed. The stress acting on the bent portion 11c can be reduced. Also, the thickness t of the entire grommet portion 11
0 and the thickness t1 of the first gasket substrate 2 and / or the thickness t2 of the second gasket substrate 3 can be set to the respective required thicknesses. It is difficult to satisfy the requirement of the thickness of the gasket substrate at the same time.
And the secondary seal portion Y can obtain good sealing properties. In this embodiment, the thickness t1 of the first gasket substrate 2 is the same as the thickness t2 of the second gasket substrate. However, the present invention is not limited to this, and the thickness t1 of the first gasket substrate 2 may be changed to the second gasket. The thickness may be set to be larger than the thickness t2 of the substrate.

Next, FIG. 3 shows a second embodiment of the present invention. In this embodiment, the outer peripheral portion of the annular member 13 is extended to a position outside the cut between the grommet portion 11 and the through hole 10. It extends and straddles the edge 10 a of the through hole 10.
The other configuration is the same as that of the first embodiment, and the same parts as those of the first embodiment are denoted by the same reference numerals. According to the present embodiment having such a configuration, it is needless to say that the same effects as those of the first embodiment can be obtained.
When the cylinder head gasket 1 is assembled to the cylinder head and the cylinder block, the folded portion 11b of the grommet portion 11 and the through hole 1 are formed on the upper surface of the annular member 13.
Since the edge 10a is pressed into contact with the zero edge 10a, it is possible to prevent the combustion gas from entering the inside of the cylinder head gasket 1 through the cut.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, a sealing member 16 having a wedge-shaped cross section is provided between the folded portion 11b of the grommet portion 11 and the edge 10a of the through hole 10. Is provided. At this time, the outer peripheral side of the annular member 13 is a folded portion 11b of the grommet portion 11.
The edge 10a of the through hole 10 is bent in advance toward the first gasket substrate 2 while being located at substantially the same position as the tip of the first hole. Thereby, the seal member 16 can be reliably held. The other configuration is the same as that of the second embodiment, and the same parts as those of the second embodiment are denoted by the same reference numerals. Therefore, according to the third embodiment having such a configuration, the same effect as that of the first embodiment can be obtained, and the airtightness between the grommet portion 11 and the through hole 10 can be obtained by the seal member 16. To prevent the combustion gas entering the cylinder head gasket 1 from the cut.

FIG. 5 shows a fourth embodiment of the present invention. In this embodiment, elastic members 17 and 18 are arranged on the inner and outer sides of the grommets 5 and 6, respectively. The two elastic members 17 and 18 are formed of heat-resistant rubber or heat-resistant resin so as not to hinder the compression deformation of the grommet portions 5 and 6. Other configurations are the first
The configuration is the same as that of the first embodiment, and the same components as those of the first embodiment are denoted by the same reference numerals as those used in the first embodiment. Therefore, according to the fourth embodiment having such a configuration, the same effects as those of the first embodiment can be obtained, and the first and second elastic members 17 and 18 can be used at the time of assembly.
The cylinder head gasket 1 is pressed against the second gasket substrates 2 and 3 so as to seal the gap therebetween.
Can be prevented from leaking to the outside of the bead portions 5 and 6 from the combustion gas that has entered the inside. In addition, it is not necessary to arrange on the inner side and the outer side of both bead portions 5 and 6,
What is necessary is just to arrange | position to either one.

In each of the above embodiments, the annular member 13 is formed to have the same thickness. However, the present invention is not limited to this. The thickness is varied in advance according to the variation in the tightening load around the combustion chamber hole. The annular member 13 may be made of a soft metal or a heat-resistant resin that can be deformed in accordance with a tightening load to obtain a uniform sealing surface pressure.

In each of the above embodiments, the shape of the annular member 13 is rectangular in cross section. However, the present invention is not limited to this. The annular ridge 1 having a semicircular cross section as shown in FIG.
9, a plurality of triangular ridges 13 ′ arranged side by side as shown in FIG. 8, or a trapezoidal cross section shown in FIG. 10 may be used.
May be a flat plate having a full bead portion 13 'shown in FIG. 11 or a half bead portion 13' shown in FIG. Depending on the setting, it may be appropriately selected and used in order to obtain an optimum sealing property.

[0015]

As described above, according to the present invention, the work of bending the grommet portion can be performed more easily than in the conventional art, and the stress acting on the bent portion of the grommet portion can be reduced. In addition, it is possible to obtain an effect that good sealing properties can be obtained simultaneously in the first seal portion and the secondary seal portion.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part along the line II-II in FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing another configuration of the annular member 13;

FIG. 7 is a sectional view showing another configuration of the annular member 13.

FIG. 8 is a sectional view showing another configuration of the annular member 13;

FIG. 9 is a sectional view showing another configuration of the annular member 13;

FIG. 10 is a sectional view showing another configuration of the annular member 13;

FIG. 11 is a sectional view showing another configuration of the annular member 13;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder head gasket 2 ... 1st gasket board 3 ... 2nd gasket board 4 ... Combustion chamber hole 5 ... 1st full bead part 6 ... 2nd full bead part 11 ... Grommet part 13 ... Ring member

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomii Yasuda 3-65 Midorigaoka, Toyota-shi, Aichi F-Term within Taiho Kogyo Co., Ltd. (Reference) 3J040 EA03 EA15 EA17 EA28 EA36 FA01 HA17

Claims (5)

[Claims] 1. A first gasket substrate having a through hole formed in accordance with a cylinder bore and a bead portion surrounding the through hole, and a first gasket substrate which is superposed on the first gasket substrate and formed in accordance with the cylinder bore. A second gasket substrate having a hole and a bead formed surrounding the through hole, and having a grommet portion formed by folding an edge of the through hole toward the first gasket substrate. In a cylinder head gasket, a tip of a grommet portion of a second gasket substrate is opposed to an edge of a through hole of the first gasket substrate, and a hole formed on an inner side of the grommet portion is formed as a combustion chamber hole. An annular member is interposed inside the grommet portion of the second gasket substrate, and a grommet with the annular member interposed is provided. The thickness of the entire mett portion is t0, the thickness of the first gasket substrate is t1, and the thickness of the second gasket substrate is t.
2, the thickness t1 of the first gasket substrate is equal to or greater than the thickness t2 of the second gasket substrate, and the thickness t0 of the entire grommet portion is the thickness of the first gasket substrate. A cylinder head gasket characterized in that the size is set to be larger than the sum of t1 and the thickness t2 of the second gasket substrate. 2. The bead portion of the first gasket substrate and the bead portion of the second gasket substrate are full bead portions whose apexes abut each other.
The cylinder head gasket according to the above. 3. An outer peripheral portion of the annular member protrudes radially outward from a grommet portion and extends to an edge of a through hole of the first gasket substrate.
Or the cylinder head gasket according to claim 2. 4. The cylinder head gasket according to claim 1, wherein a seal member is provided between a front end of the grommet portion and an edge of the through hole facing the grommet portion. 5. An annular elastic member which is elastically deformed at the time of assembling is disposed on at least one of the vicinity of an inner side position and the vicinity of an outer side position of both bead portions.
Or the cylinder head gasket according to claim 2.