JP3464780B2 - Head gasket - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head gasket for sandwiching and sealing a metal gasket between a cylinder head and a cylinder block of an internal combustion engine.

More specifically, a gasket having a sealing structure with a bead member having a bead fitted in a fitting groove provided in a gasket constituent plate, and by changing the combination of the fitting groove and the bead member, The present invention relates to a head gasket that effectively seals by adjusting a seal surface pressure for a cylinder bore and a seal surface pressure for a liquid hole to appropriate values.

[0003]

2. Description of the Related Art When sealing a joint surface between a cylinder head and a cylinder block (cylinder body) of an automobile engine, a head gasket is sandwiched between the head gasket and combustion gas and the like.

As shown in FIG. 10, this head gasket is manufactured in conformity with the shape of an engine member such as a cylinder block, and has a bore hole 2, a liquid hole such as a water hole 3 and an oil hole 4, and a bolt hole 5. Etc. are formed, and various sealing means are provided for the respective holes to be sealed.

In this sealing means, there is a great difference in the sealing performance required by the target hole even if the same gasket is used for the same engine member. That is, in the bore hole 2, it is necessary to seal the high temperature and high pressure combustion gas in the cylinder, while in the liquid holes 3 and 4, the temperature is relatively low, and not the gas seal but the liquid seal. Required.

On the other hand, in order to reduce the weight of the engine and to reduce the manufacturing cost, the head gasket is a metal type having a simple structure formed by one or two metal plates from a laminated type in which a large number of metal plates are laminated. It has become a gasket, and since the engine itself is also aimed at a lightweight, compact and high-power engine, this engine has become smaller and the distance between the cylinder bores has become narrower.

Therefore, it is difficult to use a bead, a grommet, a shim or the like which can be adopted as a sealing means in combination like a multi-layer type, and the usable area for the sealing means is decreasing. Therefore, it is necessary to use simplified and effective sealing means.

Further, in order to reduce the weight, in a small engine, an engine member is made of aluminum, which has lower rigidity than a conventional cast iron engine and is more likely to be damaged, and also has a high engine output. Since the required sealing surface pressure has become higher due to the increase in the cost, the non-resilient sealing means such as fold-back and grommets damage the aluminum engine member and cannot be used.

For this reason, in a lightweight, compact, high-power engine seal structure, an arc-shaped bead or a narrow bead having elasticity and good followability to variations in the gap are arranged in a single layer around the hole to be sealed. In many cases, it is unavoidable that the gasket 1X has a structure as shown in FIG.

[0010]

However, in the gasket 1X shown in FIG. 11, the cylinder bore hole 2 is used.
The first bead 31 around the and the second bead 3 around the liquid hole 3
2 will contact and abut the flat surface of the engine member to generate sealing surface pressure, but by pressing one metal component plate 30 to form the first and second beads 31 and 32. Therefore, the material and plate thickness of the first and second beads 31 and 32 cannot be changed.

Therefore, even if the cross-sectional shape, width, or height of the bead is not changed, the material and the plate thickness cannot be changed. Therefore, the sealing characteristics around the hole 2 for the bore and the seal around the other liquid holes 3, 4, etc. Since there is a limit to increasing the difference with the characteristics, and because the material suitable for the bead and the material suitable for the component plate are different, it is necessary to give the optimum sealing performance to each target hole. There is a problem that is difficult.

Further, in the head gasket made of one metal component plate, the cylinder bore hole 2 and the liquid holes 3, 4 are formed.
When the two are close to each other, the space between both sealing target holes becomes narrow, and the first bead 31 and the second bead 32 are provided in the respective sealing target holes in a shape and size having sufficient sealing performance. However, if the first bead 31 and the second bead 32 are too close to each other, they interfere with each other, and the deformation of the bead changes due to this interference, so that the sealing performance is particularly important. There is a problem that the target bead deformation locally and the seal surface pressure due to this deformation cannot be obtained in the vicinity of the bead.

The present invention has been made to solve these problems, and an object of the present invention is to provide a cylinder bore hole and a liquid for sealing a joint surface of a cylinder head and a cylinder block of an engine with a metal gasket. An object of the present invention is to provide a head gasket having good sealing performance and high durability, which can set a sealing surface pressure suitable for each sealing performance for each hole to perform an appropriate sealing.

[0014]

A head gasket according to the present invention for achieving the above object comprises a ring-shaped first bead member having a first bead in a first fitting groove provided around a hole for a cylinder bore. Is fitted with the convex portion on the outside, and the ring-shaped second bead member having the second bead is fitted in the second fitting groove provided around the liquid hole with the convex portion on the outside. A head gasket that seals between the cylinder head and the cylinder block, and is configured as follows.

1) In the above head gasket, the widths of the first and second fitting grooves are formed to be larger than the widths of the first and second bead members, respectively, and are generated in the first bead. A cross-sectional shape of the first bead member and the second bead member or a cross-section of the first seal groove and the second seal groove in order to make the seal surface pressure larger than the seal surface pressure generated in the second bead. It is formed by changing at least one of the shapes.

The cross-sectional shape of this bead member includes the bead material plate thickness, and the cross-sectional shape of the seal groove also includes the groove depth.

2) Alternatively, in the above head gasket, the widths of the first and second fitting grooves are formed to be larger than the widths of the first and second bead members, respectively, and the first bead is formed. In order to make the generated seal surface pressure larger than the seal surface pressure generated in the second bead, the first
At least one of the material and the processing method of the bead member and the second bead member is changed and formed.

3) In the above-mentioned head gasket, the depth of the first fitting groove is formed to be smaller than the depth of the second fitting groove.

4) Further, in the above-mentioned head gasket, the plate thickness of the first bead member is formed to be larger than the depth of the first fitting groove.

5) Further, in the above head gasket, the plate thickness of the second bead member is formed to be smaller than the depth of the second fitting groove.

In this structure, the cross-sectional shape (including the groove depth) and size and the bead of the fitting groove are set for two or more kinds of holes to be sealed having different required sealing performances such as a cylinder bore hole and a liquid hole. The sealing surface pressure can be adjusted relatively freely by changing the cross-sectional shape (including the bead material plate thickness) and size, the bead material, and the processing method such as heat treatment and press working.

In other words, a high sealing surface pressure is required around the cylinder bore hole to seal high-pressure and high-temperature combustion gas, while on the other hand, around the liquid hole to seal cooling water, circulating oil, etc., a comparison is made. Very low sealing surface pressure is required.

For these seals having different required sealing performances, for example, if the first bead is formed high or the fitting groove is formed shallow, the seal surface pressure can be increased. Further, the sealing characteristics can be changed by changing the bead cross-sectional shape to, for example, a trapezoidal shape or an arc shape.

Further, in comparison with the first fitting groove and the second fitting groove, if the depth of the first fitting groove is made smaller (shallow) than the second fitting groove, the first bead side It is easy to form a high seal surface pressure, and when the plate thickness of the first bead member is formed to be larger than the depth of the first fitting groove, the seal surface pressure generated is easily increased, and the plate of the second bead member is easily formed. If the thickness is formed to be smaller than the depth of the second fitting groove, it is easy to reduce the seal surface pressure generated.

Since the widths of the first and second fitting grooves are formed to be larger than the widths of the first and second bead members, respectively, between the fitting groove and the end of the bead member. A gap is created for absorbing the extension of the bead member in the width direction. for that reason,
Due to the fastening of engine members, the bead may be deformed by compression
Even if the bead member expands due to thermal expansion due to high temperature, the gap absorbs the elongation, so that a large stress is not generated in the bead member and the life can be extended.

The fitting groove and the bead member may be provided on only one side of the head gasket, or may be provided on both sides of the head gasket.

The above-mentioned structure of the present invention is particularly effective when the number of metal gasket laminated plates is one,
Effective even when there are a plurality of laminated plates, the cross-sectional shape and size of the bead, the material and processing method of the bead member,
The cross-sectional shape and size (in particular, width and depth) of the seal groove can be appropriately selected depending on the required sealing performance.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of an engine seal structure of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 9, a head gasket 1 according to the present invention is a metal gasket sandwiched between a cylinder head of an engine and a cylinder block (cylinder body). This seals high-pressure combustion gas and liquid such as cooling water and oil in liquid passages such as cooling water passages and cooling oil passages.

2 to 9 and 11 are schematic explanatory views, in which the thickness of the metal gasket, the size of the bead and the seal groove, and the aspect ratio are different from the actual ones, and the sealing portion is different. Is exaggerated to make it easier to understand.

As shown in FIGS. 1 to 9, the head gasket according to the embodiment of the present invention has a first annular member around the cylinder bore hole 2 of the component plate 10 of the head gasket 1.
A fitting groove 21 is provided, and the component plate 10 is provided in the first fitting groove 21.
The ring-shaped first bead member 11 formed separately from is fitted.

The first bead member 11 is the first bead 11
b, the inner peripheral edge of which is fitted to the inner peripheral wall of the first fitting groove 21. In addition, the width B1 of the first bead member 11 is set to the first width so that the expansion absorbing gap S1 is formed between the outer peripheral edge of the first bead member 11 and the outer peripheral wall of the first fitting groove 21.
It is formed to be narrower than the width X1 of the fitting groove 21.

Further, the liquid hole 3 is surrounded by the liquid hole 3 such as the water hole 3 and the oil hole 4 (hereinafter, represented by the water hole 3) arranged outside the first bead 11b of the hole 2 for cylinder bore. For this purpose, an annular second fitting groove 22 is provided, and a ring-shaped second bead member 12 formed separately from the component plate 10 is fitted into the second fitting groove 22.

The second bead member 12 is the second bead 12
b, the inner peripheral edge of which is fitted to the inner peripheral wall of the second fitting groove 12. Further, the width B2 of the second bead member 12 is set to the second width so that a gap S2 for extension absorption is formed between the outer peripheral edge of the second bead member 12 and the outer peripheral wall of the second fitting groove 22.
It is formed to be narrower than the width X2 of the fitting groove 22.

Metal constituent plate 10 of this head gasket 1
Is formed of a stainless steel plate or a spring steel plate, and the bead member may be formed of the same material as the metal component plate 10, but may be formed of various materials such as aluminum and copper.

Since the surface pressure distribution required to seal the cylinder bore 2 and the surface pressure distribution required to seal the liquid hole 3 are different, this surface pressure distribution should be adjusted so as to obtain an appropriate surface pressure distribution. 1 bead 11b and 2nd bead 12b,
The first fitting groove 21 and the second fitting groove 22 are formed by some combinations as described below. [First Embodiment] First, in the first embodiment, the first
The second fitting grooves 21 and 22 are formed with different sectional shapes or sizes, that is, the widths X1 and X2 and the depths D1 and D2.
FIG. 3 shows an example in which the depth D1 of the first fitting groove is smaller than the depth D2 of the second fitting groove (D1 ≦ D2).

In the one-piece metal gasket 1A illustrated in FIG. 2, the first bead 11b and the second bead 12b are included.
Are formed in a semi-circular shape, and the width W1 and the width W2 of the bead are made the same, and the height H1 and the height H2 of the bead are made the same, and the first fitting groove 21 and the second fitting groove 21 are formed. 22 is the width X1 of the groove
And the width X2 are the same, but the depth D1 of the groove is the depth D2.
Formed smaller than. Also, as shown in FIG.
The plate thickness t2 of the second bead member 12 and the depth of the second fitting groove 22.
Regarding the relationship with D2, the plate thickness t2 of the second bead member 12 is the second
It is formed to be smaller than the depth D2 of the fitting groove 22.
It (T2 <D2) With this configuration, the second bead 12b is formed.
The seal surface pressure generated in advance is reduced.

With this structure, the seal surface pressure generated in the first bead 11b can be made higher than the seal surface pressure generated in the second bead 12b. Second Embodiment Next, in the second embodiment, the first
The cross-sectional shape of the first bead 11b and the second bead 12b is changed so that the sealing surface pressure of the bead 11b becomes larger than the sealing surface pressure of the second bead 12b, or the size (width W1, W2 and height H1 , H2) are changed.

FIG. 2 shows an example in which the cross-sectional shape of the first bead 11b is arcuate and the cross-sectional shape of the second bead 12b is trapezoidal.

Although not shown, the first bead 11b and the second bead 12b are both formed in a semicircular shape.
The width W1 and the height H1 of the bead 11b are set to the second bead 12b.
By forming the first fitting groove 21 and the second fitting groove 22 to have the same cross-sectional shape and size (X1 = X2, D1 = D2). The sealing surface pressure generated at the first bead 11b is set to the second bead 1
It can be higher than the face seal pressure generated in 2b.
Further, as shown in FIG. 6, the plate thickness t of the second bead member 12 is
2 and the depth D2 of the second fitting groove 22, the second bead
The plate thickness t2 of the member 12 is smaller than the depth D2 of the second fitting groove 22.
It is formed to be small. (T2 <D2) to the structure
The sealing surface pressure generated in the second bead 12b is reduced.
To get rid of [Third Embodiment] Further, in the third embodiment, as shown in FIG.
The plate thickness t1 of the bead member 11 and the depth D1 of the first fitting groove 21.
The thickness t1 of the first bead member 11 is formed to be larger than the depth D1 of the first fitting groove 21.
(T1 ≧ D1) With this configuration, the seal surface pressure generated in the first bead 11b is increased. [Fourth Embodiment] In the fourth embodiment, as shown in FIG. 7, the first bead member 11 is installed on one surface of the metal component plate 10E, and the second bead member 12 is installed on the opposite surface thereof. To form.

According to this structure, even if the cylinder bore 2 and the liquid hole 3 are close to each other, it is easy to provide a bead having a size large enough to satisfy the sealing performance around each hole to be sealed. You can [ Fifth Embodiment] In the fifth embodiment, as shown in FIG. 8, first bead members 11 are installed on both surfaces of a metal component plate 10F, respectively.
The second bead member 12 is installed and formed only on one surface.

With this structure, the sealing performance on the cylinder bore hole 2 side can be relatively easily enhanced. [ Sixth Embodiment] In the sixth embodiment, as shown in FIG. 9, a first bead member 11 and a second bead member 12 are provided on both surfaces of a metal component plate 10G, respectively.

According to this structure, in the head gasket having one sheet, it is possible to easily provide the beads on both sides, so that it is possible to enhance the sealing performance for the holes 2, 3 to be sealed. [ Seventh Embodiment] In the seventh embodiment, although not shown, the first bead member and the second bead member are formed of different materials. Alternatively,
The sealing surface pressure generated in the first bead is made larger than the sealing surface pressure generated in the second bead by changing the processing method such as changing the heat treatment temperature during the processing or the pressing pressure during the pressing. .

As an example of the dimensions, when the diameter of the cylinder bore 2 is 85 mmφ, the thickness of the constituent plate 10 is about 150 μm to 2500 μm, and the bead member 1
The plate thicknesses t1 and t2 of 1 and 12 are 100 μm to 800 μm.
And the depths D1 and D2 of the fitting grooves 21 and 22 are 10
The heights H1 and H2 of the beads 11b and 12b are about 100 μm to 500 μm, and the heights H1 and H2 are about 0 μm to 1000 μm.

According to the head gasket having the above structure,
For sealing the cylinder bore hole 22 and the liquid hole 24 such as water hole and oil hole, which require different sealing surface pressure, the sealing performance suitable for each can be added, and a good seal can be obtained even in an engine with low engine rigidity. To be

[0046]

As described above, according to the engine seal structure of the present invention, the bead can be formed separately from the gasket component plate, and the extension absorbing gap is provided.
Since it fits in the fitting groove formed in the gasket component plate, it is relatively easy to dispose the optimum bead for generating the sealing surface pressure required around each hole to be sealed.

Especially for the cylinder bore hole and the liquid hole,
It is relatively easy to individually adjust the generated seal surface pressure by changing the cross-sectional shape and size of the seal groove, the cross-sectional shape and size of the bead, the material of the bead member, and the processing method such as heat treatment and processing pressure. Since it can be done, it is easy to generate the sealing surface pressure required for each sealing target hole,
Proper sealing can be performed.

Therefore, it is possible to easily provide the sealing performance suitable for each of the cylinder bore holes and the liquid holes such as water holes and oil holes, which require different sealing surface pressures.

[Brief description of drawings]

FIG. 1 is a plan view showing a head gasket of a first embodiment according to the present invention.

FIG. 2 is a schematic drawing showing a head gasket according to the present invention, and FIG. 2 (a) is an exploded perspective view including a cross section taken along line XX of FIG.

FIG. 3 is a schematic view showing the head gasket of the first embodiment according to the invention, and is a cross-sectional view taken along line XX of FIG. 1 after fitting and integration.

FIG. 4 is a schematic view showing a head gasket of a second embodiment according to the invention, and is a cross-sectional view taken along line XX of FIG. 1 after fitting and integration.

FIG. 5 is a schematic view showing a head gasket of a third embodiment according to the invention, and is a partial cross-sectional view of a first bead portion after fitting and integration.

FIG. 6 is a schematic view showing a head gasket of a fourth embodiment according to the invention, and is a partial cross-sectional view of a second bead portion after fitting and integration.

FIG. 7 is a schematic view showing a head gasket of a fifth embodiment according to the invention, and is a cross-sectional view taken along line XX of FIG. 1 after fitting and integration.

FIG. 8 is a schematic view showing a head gasket of a sixth embodiment according to the invention, and is a cross-sectional view taken along line XX of FIG. 1 after fitting and integration.

FIG. 9 is a schematic view showing a head gasket of a seventh embodiment according to the invention, and is a cross-sectional view taken along line XX of FIG. 1 after fitting and integration.

FIG. 10 is a plan view showing a conventional head gasket.

11 is a partial perspective view including a schematic cross section showing the structure of the XX cross section in FIG.

[Explanation of symbols]

1 head gasket 2 Cylinder bore hole 3 liquid holes 11 First bead member 11b first bead 12 Second bead member 12b second bead 21 First fitting groove 22 Second fitting groove

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Claims (4)

(57) [Claims] 1. A ring-shaped first bead member having a first bead is fitted in a first fitting groove provided around a hole for a cylinder bore with a convex portion being an outer side, and is provided around a liquid hole. A head gasket that seals between a cylinder head and a cylinder block of an engine, in which a ring-shaped second bead member having a second bead is fitted in a second fitting groove with a convex portion on the outside. The width of the second fitting groove is formed to be larger than the widths of the first and second bead members over the entire circumference, and the sealing surface pressure generated in the first bead is set to the second
At least one of the cross-sectional shapes of the first bead member and the second bead member or the cross-sectional shapes of the first seal groove and the second seal groove is changed so as to be larger than the seal surface pressure generated in the bead. And further, the second
The thickness of the card member is smaller than the depth of the second fitting groove.
A head gasket characterized by being made. 2. A ring-shaped first bead member having a first bead is fitted into a first fitting groove provided around the hole for the cylinder bore with the convex portion being the outside, and is provided around the liquid hole. A head gasket that seals between a cylinder head and a cylinder block of an engine, in which a ring-shaped second bead member having a second bead is fitted in a second fitting groove with a convex portion on the outside. The width of the second fitting groove is formed to be larger than the widths of the first and second bead members over the entire circumference, and the sealing surface pressure generated in the first bead is set to the second
At least one of the material and the processing method of the first bead member and the second bead member is changed so as to be larger than the seal surface pressure generated in the bead, and further,
The thickness of the second bead member is smaller than the depth of the second fitting groove.
A head gasket characterized by being formed into a ring. 3. The depth of the first fitting groove is formed to be smaller than the depth of the second fitting groove.
The head gasket according to item 2. 4. The head gasket according to claim 1, wherein the plate thickness of the first bead member is formed to be larger than the depth of the first fitting groove.