JP3078826B2 - Cylinder head gasket - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cylinder head gasket interposed between a cylinder head and a cylinder block of an engine.

[Conventional technology]

In recent years, engines have tended to have higher horsepower and higher rpm,
This trend has resulted in increased combustion pressure and increased thermal load. At the same time, in recent years, engines have tended to be lighter, which has led to a decrease in the rigidity of the cylinder head and cylinder block. For this reason, the structural deformation of the cylinder head and the cylinder block due to the combustion pressure and the thermal deformation due to the thermal load are increasing, and the cylinder head gasket has been subjected to extremely severe conditions.

Under these circumstances, it has become impossible to shield successfully with conventional soft gaskets,
Metal-laminated cylinder head gaskets have been widely used in recent years. The cylinder head gasket shown in FIGS. 9 and 10 and the cylinder head gasket shown in FIGS. 11 and 12 are made of a conventional metal-laminated cylinder head gasket, which is made of compressible fibers such as aramid fiber and synthetic rubber. Upper surface plate 2 made of a stainless steel plate or the like coated on both sides with a compressible material layer 1 made of a compound containing an elastomer such as
And a lower surface plate 3 on both sides of a center plate 4 made of a stainless steel plate or the like.

Even in such a metal-laminated cylinder head gasket, the combustion chamber gas needs to maintain a gas seal at a high surface pressure. Therefore, usually, a gas seal portion provided with a bore grommet and a remaining portion (that is, a water and oil seal) are used. Part) is provided with a step of about 0.1 mm. On the other hand, the remaining upper and lower surfaces 2,3 for water and oil seals
Are coated with a compressible material layer 1 of about 0.01 to 0.15 mm on one side, so that when the gasket is tightened, the remaining part of the cylinder head, especially the less rigid parts (particularly the front and rear parts) of the cylinder head, Deformation increases. FIG. 13 illustrates such a deformation of the cylinder head gasket (in this figure, 5 is the cylinder head, 6 is the cylinder head gasket,
7 shows a cylinder block).

Under such a condition, the cylinder bore deformation (increased oil consumption) and the variation in the roundness of the camshaft (increased oil consumption) are increased, and the thermal deformation of the cylinder head during operation at the corresponding portion is reduced. Of course, and it has developed into problems such as gas leaks, water leaks, and oil leaks.

Conventionally, the following two methods (A) and (B) have been adopted as countermeasures against such problems.

(A) As shown in FIGS. 9 and 10, a shim 8 made of a thin metal plate is inserted between the upper surface plate and the center plate at a portion where the rigidity of the cylinder head is weak and the deformation is large (FIG. 9). In the figure, the hatched portion of the broken line indicates the portion where the shim 8 is inserted.) A part of the shim 8 is annularly extended, and the annular extended portion is fitted into the bore grommet 9 and the bore grommet 9 is fitted.
The shim 8 is fixed to the gasket by being sandwiched inside.

(B) As shown in FIGS. 11 and 12, the grommet 10 is attached to a necessary portion, and the grommet 10 is fixed to the gasket by caulking the grommet 10 into the bolt hole 11.

[Problems to be solved by the invention]

However, the method (A) has the following disadvantages.

(A) Since the shim 8 is fitted into the bore grommet 9 and is sandwiched in the grommet 9, a part of the shim 8 must be annularly extended to the outer periphery of the cylinder bore. Is bad.

(B) Since the contact surface between the shim 8 and the center plate 4 is in metal contact, interlayer leakage is likely to occur.

(C) Since the shim 8 is thin, it tends to protrude to the outer periphery of the gasket due to structural deformation and thermal deformation of the cylinder head during operation, and consequently to gas, water and oil leaks.

The method (B) has the following disadvantages.

(B) When performing this method, the ends of the face plates 2 and 3 and the center plate 4 are sandwiched between the grommets 10 so that the
Grommet 10 due to the need to bend 10
The thickness t ₁₀ of the required or 0.10 mm (When the grommet 10 is thinner than that, occurs processed during cracking) On the other hand, the compressible material layer 1 is extremely small compressibility and 0.02 to 0.1 mm,
Too thick plate thickness t ₀ of the grommet mounting portion becomes excessive level difference (t ₀ -t ₁₎ of the other sites, to increase the deformation of the deformation direction opposite of the cylinder head, to the surrounding water and oil seal And the gas seal.

(B) In the tightening state, a large surface pressure is required for the water and oil seals due to metal contact with the cylinder head and the block surface.

The present invention has been made in view of such circumstances, and a shim having an arbitrary thickness can be used at a necessary portion according to deformation of a cylinder head at the time of tightening. Deformation can be extremely reduced, there is no interlayer leakage between the center plate and the shim,
It is an object of the present invention to provide a cylinder head gasket which does not protrude a shim during operation, has a good material yield, and is extremely easy to adjust a step between a bore grommet portion and a remaining portion.

[Means for solving the problem]

The cylinder head gasket according to the present invention is characterized in that a surface plate formed by coating a compressible material layer made of a compound containing a compressible fiber and an elastomer on both surfaces of a metal plate is laminated on an upper surface side and a lower surface side of a central plate made of a metal plate. In the cylinder head gasket, a portion of the center plate corresponding to a portion where the cylinder head is likely to be deformed when tightened is made of a metal plate with an adhesive having heat resistance, water resistance and oil resistance. Shim bonded.

[Action]

In the present invention, a shim having an arbitrary thickness can be inserted into each part according to the deformation of the cylinder head at the time of tightening. Therefore, deformation of the cylinder head at the time of tightening can be extremely reduced.

Further, since the center plate and the shim are bonded with an adhesive having heat resistance, water resistance, and oil resistance, there is no interlayer leakage between the center plate and the shim.

Further, since the shim is firmly bonded to the center plate with a heat-resistant adhesive, the shim does not protrude to the outer peripheral portion of the gasket during operation due to deformation of the cylinder head.

Also, in order to fix the shim to the gasket, it is not necessary to extend a part of the shim annularly to the outer periphery of the cylinder bore, and it is only necessary to bond the shim to a necessary portion only in a necessary area,
Good material yield.

Further, since the selection range of the thickness of the bore grommet portion is very narrow, the method of sandwiching the shim 8 in the bore grommet 9 in the above-mentioned conventional method (A) eliminates the step between the bore grommet portion and the remaining portion. In the present invention, such a compromise was not necessary, so that the step between the bore grommet portion and the remaining portion can be easily designed to an ideal size. Can be.

〔Example〕

Hereinafter, the present invention will be described based on embodiments shown in the drawings.

1 to 8 show an embodiment of the present invention. In this embodiment, the gasket main body 21 is composed of a center plate 22 (plate thickness 0.2 mm) made of a stainless steel plate and two surface plates 23 and 24 superimposed on both surfaces thereof, respectively. They are connected to each other by rivets 25 as shown in FIGS. The surface plates 23 and 24 are formed of thin compressible material layers 23b and 24b made of a mixture of compressible fibers such as aramid fibers and elastomers such as synthetic rubber on both sides of thin stainless steel plates 23a and 24a (plate thickness 0.45 mm). (The coating thickness is 0.075 mm per side).

The center plate 22 and the surface plates 23 and 24 are provided with four cylinder holes 26, and as shown in FIG.
The surface plates 23 and 24 are not overlapped with each other, and the backing plate 27 (plate thickness 0.25 mm) made of stainless steel is placed on the upper surface of the center plate 22 and the backing plate 28 (plate thickness 0.15 mm) is placed on the lower surface, respectively. Above, a bore grommet 29 (plate thickness 0.3 mm) made of stainless steel is mounted so as to sandwich the backing plates 27 and 28 and the center plate 22.

Half beads 30 are formed on the surface plates 23 and 24 by press working so as to surround the four cylinder holes 26. In the center plate 22 and the surface plates 23 and 24, a water hole 31 for passing cooling water is provided inside the half bead 30, an oil hole 32 for passing lubricating oil and a bolt for inserting a tightening bolt. Holes 40 are provided outside the half beads 30 respectively. Each oil hole 32 of the surface plates 23, 24
A half bead 33 is formed by press working around the periphery of.

A part of the center plate 22 where the rigidity of the cylinder head is small and the cylinder head is likely to be deformed at the time of tightening is provided with an adhesive 34 such as a phenol-based adhesive having heat resistance and resistance to cooling water and lubricating oil. The shims 35, 36, and 37 made of a metal plate are adhered to each other (shown only in FIG. 3) (in FIG. 2, the insertion portions of these shims are indicated by dashed broken lines). The thickness of the shims 35 to 37 is determined according to the amount of deformation of the cylinder head. In the present embodiment, the thickness of the shims 35 and 36 is 70 μm, and the thickness of the shim 37 is 50 μm. The layer of the adhesive 34 has a thickness of 5 to 10 μm.

In this cylinder head gasket, shims 35 to 37 having an arbitrary thickness can be inserted into each part according to the deformation of the cylinder head at the time of tightening. Therefore, deformation of the cylinder head at the time of tightening can be extremely reduced.

Further, since the center plate 22 and the shims 35 to 37 are bonded with an adhesive 34 having heat resistance, water resistance and oil resistance, there is no interlayer leakage between the center plate 22 and the shims 35 to 37.

Since the shims 35 to 37 are firmly bonded to the center plate 22 with the heat-resistant adhesive 34, the shims 35 to 37 do not protrude to the outer peripheral portion of the gasket during operation due to deformation of the cylinder head. .

In addition, it is not necessary to extend a part of the shims 35 to 37 in an annular shape to the outer periphery of the cylinder bore in order to fix the shims 35 to 37 to the gasket.
The material yield of the shims 35 to 37 is good.

Further, the selection range of the thickness of the bore grommet portion is very narrow. Therefore, in the method of sandwiching the shim in the bore grommet of the conventional method (A), it is necessary to compromise and determine the step between the bore grommet portion and the remaining portion in relation to the thickness of the bore grommet portion. In the present invention, since such a compromise is not required, the step between the bore grommet 29 and the remaining portion can be easily designed to an ideal size.

In the cylinder head gasket of the present invention,
Although the thickness of each part is not limited to the value of the above embodiment, the thickness of the shim is 20 to 100 μm, and the thickness of the compressible material layers 23b and 24b is 20 to 100
μ, the thickness of the layer of the adhesive 34 is preferably 5 to 10 μ.

Further, the metal material used in the cylinder head gasket of the present invention is not limited to stainless steel as in the above embodiment.

〔The invention's effect〕

As described above, the cylinder head gasket according to the present invention can significantly reduce (a) the deformation of the cylinder head when tightened.

(B) There is no interlayer leakage between the center plate and the shim.

(C) The shim does not protrude to the outer periphery of the gasket during operation.

(D) Good yield of shim material.

(E) Adjustment of the step with the remaining portion of the bore grommet portion is extremely simple.

And other excellent effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a shim mounting portion of an embodiment of a cylinder head gasket according to the present invention (the sectional position is II in FIG. 2).
2) is a plan view showing the above embodiment, and FIG.
FIG. 4 is an enlarged cross-sectional view of a main part of the cross-sectional view of FIG. 2, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2, FIG. 5 is a cross-sectional view taken along line VV of FIG. FIG. 7 is a sectional view taken along line VI-VI of FIG. 2, FIG. 7 is a sectional view taken along line VII-VII of FIG. 2, FIG. 8 is a sectional view taken along line VIII-VIII of FIG.
9 is a plan view showing a conventional metal-laminated cylinder head gasket, FIG. 10 is a sectional view taken along line XX of FIG. 9, and FIG. 11 is a plan view showing another conventional metal-laminated cylinder head gasket. FIG. 12 is a sectional view taken along line XII-XII of FIG. 11, and FIG. 13 is an explanatory view showing a deformation of a cylinder head and a cylinder block in the engine. 22 ... central plate, 23, 24 ... surface plate, 23a, 24a ... stainless steel plate, 23b, 24b ... compressible material layer, 26 ... cylinder hole, 34 ... adhesive, 35-37 ... shim .

Continuation of the front page (72) Inventor Wataru Sato 305 Isshiki, Ishiki, Koyama-cho, Sunto-gun, Shizuoka Prefecture (56) References JP-A-62-113968 (JP, A) JP-A-1-182563 (JP) , A) Real opening 63-112261 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16J 15/00-15/14

Claims (1)

(57) [Claims] 1. A surface plate obtained by coating a compressible material layer made of a compound containing a compressible fiber and an elastomer on both surfaces of a metal plate is laminated on the upper and lower surfaces of a central plate made of a metal plate. In the cylinder head gasket, a shim made of a metal plate is bonded to a portion of the center plate corresponding to a portion where the cylinder head is likely to be deformed at the time of tightening with an adhesive having heat resistance, water resistance, and oil resistance. A cylinder head gasket.