JP2010091025A - Cylinder head gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder head gasket for maintaining good sealing performance for a long period. <P>SOLUTION: The cylinder head gasket 1 comprises at least one first seal plate 11 to be held between a cylinder head 2 and a cylinder block 3 having a cylinder bore 4. The first seal plate has an uneven porion 11b formed ranging over between a position on the side of a combustion chamber hole beyond at least an opening portion of a water jacket 5 and a position beyond an edge 5a of the opening portion on the side of the combustion chamber hole while being protruded on the surface and reverse of the first seal plate. When the cylinder head gasket 1 is held between the cylinder head 2 and the cylinder block 3, the uneven portion 11b is locked to the edge 5a. Thus, the uneven portion 11b can firmly lock the cylinder head and the cylinder block to each other and its locking force can suppress the deformation of the cylinder block due to the explosive pressure of an engine, thereby preventing the degradation of sealing performance and reducing the consumption of oil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cylinder head gasket, and more particularly, to a cylinder head gasket sandwiched between a cylinder head and a cylinder block having a cylinder bore.

2. Description of the Related Art Conventionally, as a cylinder head gasket, a combustion chamber provided with at least one first seal plate sandwiched between a cylinder head and a cylinder block having a cylinder bore, and formed in the position of the cylinder bore in the first seal plate It is well known that a hole and a first full bead surrounding the combustion chamber hole are provided on the combustion chamber side of the water jacket opening on the surface of the cylinder block.
The first seal plate is provided with a protruding portion that protrudes into the water jacket, and when the cylinder head gasket is sandwiched between the cylinder head and the cylinder block, the protruding portion is protruded into the water jacket. In addition, there is known a structure in which an edge portion on the combustion chamber hole side in the opening portion of the water jacket is locked to the protruding portion. (Patent Document 1, Patent Document 2).
JP 2003-129903 A JP-A-9-303560

Incidentally, the cylinder block of the engine is slightly elastically deformed by the explosion pressure in the combustion chamber during engine operation. In particular, in an open deck type cylinder block in which a water jacket is formed around a plurality of cylinder bores arranged in series and the water jacket is opened on the upper surface of the cylinder block, compared to a cylinder block that is not an open deck type. The elastic deformation on the cylinder bore side is larger than that of the water jacket.
This elastic deformation is relatively large between adjacent bores of the cylinder block, and in the worst case, there is a risk of cracking.

In the conventional cylinder head gasket provided with the above-described protrusion, the edge of the water jacket opening on the combustion chamber hole side can be locked to the protrusion, so that the elastic deformation of the cylinder block is caused by this protrusion. Can be suppressed.
However, since the protrusion in Patent Document 1 protrudes in a V shape into the opening of the water jacket, the protrusion is almost flat when the cylinder head gasket is sandwiched between the cylinder head and the cylinder block. As a result, it is difficult to maintain a good state of engagement between the edge of the opening of the water jacket and the protrusion. As a result, a sufficient effect of suppressing the elastic deformation of the cylinder block could not be expected.

On the other hand, since the protrusion in Patent Document 2 protrudes stepwise into the opening of the water jacket, even if the cylinder head gasket is sandwiched between the cylinder head and the cylinder block, the edge of the opening of the water jacket And the stepped protrusion can be maintained in a favorable state.
However, it is actually quite difficult to accurately engage the stepped portion of the protrusion formed on the first seal plate and the edge of the water jacket opening on the combustion chamber hole side, If a gap due to a manufacturing error occurs between the two, the effect of suppressing the elastic deformation of the cylinder block could not be expected.
In view of such circumstances, the present invention allows the first seal plate and the edge of the opening on the combustion chamber hole side to be more easily and reliably engaged, and allows the cylinder block to be elastically deformed. The present invention provides a cylinder head gasket that can be suppressed as much as possible and maintain good sealing performance for a long period of time.

In other words, the invention of claim 1 is provided with at least one first seal plate sandwiched between a cylinder head and a cylinder block having a cylinder bore, and the first seal plate has a combustion bored at the position of the cylinder bore. In a cylinder head gasket provided with a chamber hole and a first full bead surrounding the combustion chamber hole on the combustion chamber side with respect to the water jacket opening on the surface of the cylinder block,
The first seal plate includes at least a first seal between a position closer to the combustion chamber hole than the opening of the water jacket and a position beyond the edge of the opening on the combustion chamber hole side. At least a pair of concavo-convex portions projecting from the front and back surfaces of the plate are formed, and the concavo-convex portions are locked to the edge of the opening on the combustion chamber hole side.

According to the above configuration, since the uneven portion protrudes from the front and back surfaces of the first seal plate, when the first seal plate is sandwiched between the cylinder head and the cylinder block, the protruded portion of the uneven portion is It protrudes toward the cylinder block, and the uneven portion extends between a position on the combustion chamber hole side of the opening of the water jacket and a position beyond the edge of the opening on the combustion chamber hole side. Therefore, the uneven portion of the first seal plate and the edge portion can be reliably locked.
As a result, deformation of the cylinder block due to the explosion pressure of the engine can be suppressed, so that cracking of the cylinder block due to the deformation can be prevented, and between the cylinder head gasket and the cylinder block, and between the cylinder head gasket and the cylinder. The occurrence of rubbing with the head can be suppressed.

Hereinafter, the present invention will be described with reference to the illustrated embodiment. In FIG. 2, the cylinder head gasket 1 of the present embodiment is sandwiched between the cylinder head 2 and the cylinder block 3 to seal between them. .
In the embodiment shown in FIG. 1, the cylinder block 3 includes four cylinder bores 4 arranged in series on a straight line, and a water jacket 5 is formed around each cylinder bore 4 so as to surround them. The water jacket 5 is opened on the upper surface of the cylinder block 3.

As shown in FIG. 2, the cylinder head gasket 1 includes a metal first seal plate 11 and a second seal plate 12, which are respectively provided with a cylinder bore 4 of the cylinder block 3. Four combustion chamber holes 14 are formed so as to match the above.
Further, as shown in FIG. 1, each of the seal plates 11 and 12 has a plurality of bolt holes 15 for inserting fastening bolts (not shown) and blow-by holes 16 through which blow-by gas flows. .

The first seal plate 11 and the second seal plate 12 are formed with full beads 11a and 12a surrounding the respective combustion chamber holes 14 in an endless manner, and the lower first seal plate that comes into contact with the cylinder block 3 is formed. A full bead 11 a formed on 11 is formed so as to protrude downward toward the cylinder block 3.
On the other hand, the full beads 12 a formed on the upper second seal plate 12 are formed so as to protrude upward toward the cylinder head 2.

Each surface of the first seal plate 11 and the second seal plate 12 is coated with a coating material 18 such as a fluorine or nitrile rubber or elastomer material.
The coating material 18 is provided for the purpose of improving the adhesion and sealing properties with the counterpart material, respectively, and in order to ensure slipperiness and non-adhesiveness as required, the coating material 18 is used. A top coat such as graphite or wax may be applied to the surface of

Next, as shown in FIGS. 1 and 2, the first seal plate 11 on the cylinder block 3 side has a position closer to the combustion chamber hole than the opening of the water jacket 5 and the combustion chamber hole of the opening. In the illustrated embodiment, at least a pair of concavo-convex portions 11b projecting from the front and back surfaces of the first seal plate 11 are formed between the positions beyond the side edge portion 5a.
Further, the second seal plate 12 on the cylinder head 2 side is formed with a pressing portion 12b having an arcuate cross section that bulges toward the cylinder block 3 at a position where it overlaps with the concave and convex portion 11b. The concavo-convex portion 11 b can be bulged toward the cylinder block 3.

As shown in FIG. 1, the uneven portion 11b and the pressing portion 12b are formed in an endless shape so as to surround the four combustion chamber holes 14 in common, and the cylinder head gasket 1 is connected to the cylinder head 2 and the cylinder block. 3, the edge portion 5 a of the water jacket 5 is engaged with the concavo-convex portion 11 b.
At this time, the pressing portion 12b is superposed on the concavo-convex portion 11b and pressed so as to bulge toward the cylinder block 3, so that the edge portion 5a of the water jacket 5 is more effectively concavo-convex portion 11b. It will be locked to.
The concavo-convex portion 11b may have any shape as long as it can be engaged with the edge 5a of the water jacket 5. For example, the concavo-convex portion 11b may be concentric concavo-convex centered on the center of the combustion chamber hole 14, Alternatively, a lattice shape may be used.

Further, in this embodiment, the coating material 18 coated on each surface of the first seal plate 11 is omitted at the position where the uneven portion 11b is formed, and on the surface of the uneven portion 11b on the cylinder block 3 side, A coating material 20 having a high friction coefficient based on polyimide, polyamideimide, phenol resin or epoxy resin is provided.
As a result, the edge portion 5a of the water jacket 5 is bitten into the coating material 20, so that the slip between the edge portion 5a of the water jacket 5 and the convex portion of the concavo-convex portion 11b can be suppressed better. is there.

In the above configuration, when the cylinder head gasket 1 is sandwiched between the cylinder head 2 and the cylinder block 3, the uneven portion 11b of the first seal plate 11 is closer to the combustion chamber hole than the opening of the water jacket 5. And the edge 5a of the opening on the combustion chamber side of the water jacket 5 is always formed. It comes to be locked to the uneven portion 11b.
In the present embodiment, the coating material 20 having a high friction coefficient is provided on the surface of the concavo-convex portion 11b on the cylinder block 3 side, and the concavo-convex portion 11b is further bulged toward the cylinder block 3 by the pressing portion 12b of the second seal plate 12. Since it is pressed so as to come out, the edge portion 5a of the water jacket 5 is more firmly locked to the uneven portion 11b.
As a result, it is possible to suppress the cylinder block 3 that is particularly inside the water jacket 5 from being bent outward in the radial direction of the bore 4 due to the explosion pressure on the cylinder bore 4 side.
If local deformation of the cylinder block 3 can be effectively suppressed, rubbing between the cylinder block 3 and the first seal plate 11 caused by the cylinder block 3 and the cylinder head 2 and the second seal plate 12 are caused. Can be prevented, and the deterioration of the sealing performance caused by the rubbing can be prevented.

Furthermore, according to the present embodiment, the oil consumption can be reduced. That is, when the cylinder block is locally deformed by the explosion pressure of the engine and the roundness of the cylinder bore is reduced as in the conventional case, the surface pressure when sliding with the bore inner surface of the piston ring is increased and decreased. At low locations, the oil scraping ability on the bore surface is reduced, which increases oil consumption.
On the other hand, in the present embodiment, since the cylinder block is effectively suppressed from being locally deformed by the uneven portion 11b, it is possible to suppress the occurrence of strength and weakness in the surface pressure of the piston ring. This can prevent the oil scraping ability from being lowered by the piston ring and reduce the oil consumption.

FIG. 3 shows a second embodiment of the present invention. The second seal plate 12 of this embodiment has a configuration in which the pressing portion 12b is omitted from the second seal plate 12 of the first embodiment. Yes. And between the 1st seal plate 11 and the 2nd seal plate 12, the ring-shaped metal shim plate 17 which increases the surface pressure around each combustion chamber hole 14 is provided, and this shim plate 17 It is arranged for each cylinder bore 4.
The ring-shaped shim plates 17 arranged for each cylinder bore 4 are integrally connected to each other at an intermediate position of each cylinder bore 4, thereby improving the ease of assembly. However, the shim plate 17 may be manufactured separately.
Other configurations are the same as those of the first embodiment, and the same or corresponding parts are denoted by the same reference numerals.
Also in this embodiment, since the concavo-convex portion 11 b protrudes from the front and back surfaces of the first seal plate 11, the convex portion of the concavo-convex portion 11 b is pushed out to the cylinder block 3 side by the shim plate 17. 5 edge portions 5a can be locked to the uneven portion 11b.
Further, in this embodiment, the surface pressure around each combustion chamber hole 14 can be adjusted by the shim plate 17 to be optimum.
Also in the first embodiment, similarly to the second seal plate 12 in the second embodiment, the pressing portion 12b can be omitted.

FIG. 4 shows a third embodiment of the present invention, which is a simplification of the first embodiment.
That is, in this embodiment, the second seal plate 12 on the cylinder head 2 side is omitted from the first embodiment described above, and the coating material 20 is omitted from the first seal plate 11 and the coating material 20 is omitted. In addition, the coating material 18 is coated in the same manner as the other portions.
Other configurations are the same as those of the first embodiment, and the same or corresponding parts are denoted by the same reference numerals.
Also in the present embodiment, the edge portion 5a of the water jacket 5 can be locked to the uneven portion 11b.

FIG. 5 shows a fourth embodiment of the present invention. In the first embodiment, the concavo-convex portion 11b is formed in an endless shape so as to surround the four combustion chamber holes 14 in common. In FIG. 4, the uneven portion 11b is partially formed in consideration of the position where the elastic deformation is increased.
In the present embodiment, as described above, the elastic deformation of the cylinder block 3 is relatively large between the adjacent bores 4 and 4, and therefore, at a plurality of locations close to the adjacent bores 4 and 4 in order to suppress it. Concave and convex portions 11b are formed, and concave and convex portions 11b 'are also formed at outer positions on both sides in the series direction of the four cylinder bores 4 arranged in series on a straight line.
And the press part 12b formed in the 2nd seal plate 12 is also provided in the position which formed them so that it may superimpose on each said uneven | corrugated | grooved part 11b, 11b '.
Other configurations are the same as those of the first embodiment, and the same or corresponding parts are denoted by the same reference numerals.
Even in such a configuration, the elastic deformation of the cylinder block 3 can be satisfactorily suppressed.

Of course, in the second to third embodiments, the uneven portion 11b may be partially formed as in the fourth embodiment.
In addition, the formation range of the uneven portion 11b may be provided over a range from the front of the edge on the combustion chamber hole 14 side in the opening of the water jacket 5 to the position beyond the opposite edge.

The top view which shows 1st Example of this invention. The expanded sectional view which follows the II-II line of FIG. Sectional drawing which shows 2nd Example of this invention. Sectional drawing which shows 3rd Example of this invention. The top view which shows 4th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head gasket 2 Cylinder head 3 Cylinder block 4 Cylinder bore 5 Water jacket 11, 12 Seal plate 11a, 12a Full bead 11b Uneven part 12b Press part 14 Combustion chamber hole 17 Shim plate 18 Coating material 20 Coating material

Claims (8)

At least one first seal plate sandwiched between a cylinder head and a cylinder block having a cylinder bore is provided, the first seal plate has a combustion chamber hole drilled at the position of the cylinder bore, and the cylinder block In the cylinder head gasket provided with the first full bead surrounding the combustion chamber hole on the combustion chamber side with respect to the water jacket opened on the surface,
The first seal plate includes at least a first seal between a position closer to the combustion chamber hole than the opening of the water jacket and a position beyond the edge of the opening on the combustion chamber hole side. A cylinder head gasket characterized in that at least a pair of concavo-convex portions projecting from the front and back surfaces of the plate are formed, and the concavo-convex portions are engaged with an edge of the opening on the combustion chamber hole side.   A second seal plate is laminated on the cylinder head side of the first seal plate, and a second full bead surrounding the combustion chamber hole is formed at a position where the second seal plate overlaps with the first full bead. The cylinder head gasket according to claim 1, wherein   3. The cylinder head gasket according to claim 2, wherein a pressing portion that bulges the concavo-convex portion toward the cylinder block is provided at a position overlapping the concavo-convex portion of the second seal plate.   A shim plate is provided between the first seal plate and the second seal plate, which extends from the combustion chamber hole to a position beyond the concavo-convex portion and increases the surface pressure around the combustion chamber hole. The cylinder head gasket according to claim 2.   The cylinder head gasket according to any one of claims 1 to 4, wherein the concavo-convex portion is formed in an endless shape surrounding the cylinder bore.   The cylinder head gasket according to any one of claims 1 to 4, wherein the uneven portion is partially formed at a required position surrounding the cylinder bore.   7. The cylinder head gasket according to claim 1, wherein the surface of the seal plate is coated with a coating material such as a fluorine or nitrile rubber or elastomer material.   The coating material having a high friction coefficient based on polyimide, polyamideimide, phenol resin, epoxy resin or the like is provided on the cylinder block side surface of the uneven portion. The cylinder head gasket according to any one of 7.

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