JP2002322945A - Cylinder head gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder head gasket 1 having a preferable sealability as compared with the conventional art. SOLUTION: The cylinder head gasket 1 includes a first gasket substrate 5 and a second gasket substrate 6, an inner plate 7 which is interposed therebetween, and further a spacer 8 stuck to a lower surface of the inner plate 7. The inner plate 7 is formed with an annular stepped portion 7A in such a manner that it surrounds a combustion chamber hole 12 and that it is located at the position above a cylinder liner 3. Both gasket substrates 5, 6 are formed with full bead sections 5A, 6A at the positions above an upper surface 6A of a cylinder block 2, respectively. An upper end surface 3A of the cylinder liner 3 is pressed by the annular stepped portion 7A serving as a lower planar pressure section at appropriate planar pressure, to thereby prevent the cylinder liner 3 from being depressed or raised.

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 suitable for an engine in which a cylinder liner is press-fitted into a through hole of a cylinder block.

[0002]

2. Description of the Related Art Conventionally, there has been known an automobile engine in which a through hole is formed in a cylinder block and a cylindrical cylinder liner is press-fitted into the through hole. In such a conventional engine, after a cylinder liner is press-fitted into a through hole of a cylinder block, an upper end surface of the cylinder liner is cut by a milling machine. Care is taken to make it flush with the top surface. Even in a conventional engine equipped with such a cylinder liner, a cylinder head gasket is interposed between a cylinder block and a cylinder head to maintain a seal therebetween.

[0003]

However, the following disadvantages have been pointed out in the cylinder head gasket used for the engine equipped with the above-mentioned cylinder liner. That is, in the above-described engine, first, before assembling the cylinder head gasket, the upper surface of the cylinder liner is not completely located on the same plane as the upper surface of the cylinder block, and the cylinder liner is protruded. It may be in a state where it is sunk, a state where it sinks, or a state where both are mixed around the cylinder bore.
In the conventional cylinder head gasket, the presence or absence of the cylinder liner is hardly taken into consideration, and regardless of the boundary between the cylinder liner and the cylinder block, a thick surface such as shim, grommet, turn-back, etc. is provided around the cylinder bore The pressure was generated.
Therefore, due to the unevenness of the upper end surface of such a cylinder liner, the surface pressure becomes too high in the convex portion and becomes too low in the concave portion, so that there is a problem that the initial sealing property becomes unstable. By the way, the cylinder liner is pressed into the cylinder block with a slight taper. On the other hand, when the engine is operated and heated, the tightening force of the press-fitted cylinder liner is reduced. In this state, the force of the cylinder head gasket pressing the upper end surface of the cylinder liner (the surface pressure of the cylinder liner) is increased. If it is too strong, there is a problem that the liner sinks in the portion that is too strong. The decrease in the tightening force is considered to be caused by a difference in thermal expansion due to a difference in material, such as a cylinder liner made of cast iron and a cylinder block made of aluminum. The tightening force decreases as the temperature increases. In particular, since the temperature on the exhaust side and between the bores becomes high, the cylinder liner tends to sink in this portion. On the other hand, the cylinder liner tightening force that has been reduced during operation heating increases during cooling when the engine is stopped, and tends to return to the original state. In this state, if the force of pressing the upper end surface of the cylinder liner by the cylinder head gasket (the surface pressure of the cylinder liner portion) is too weak, there is a problem that the cylinder liner protrudes in an excessively weak portion contrary to the heating. . This overhang is due to the fact that the cylinder liner has a slight taper to press fit into the cylinder block. Then, as described above, when the cylinder liner sinks due to the heating of the engine and repeatedly protrudes due to cooling, the cylinder liner tightening force gradually decreases due to wear of the cylinder liner and the cylinder block, and the cylinder liner rattles. Problems such as seizure of the piston could occur. To solve the above problem, a conventional cylinder head gasket having a thick portion such as a shim, a grommet, and a turn around the cylinder bore has a structure in which a high surface pressure due to a thick wall is formed at a position above the cylinder liner. there were. Therefore, in such a conventional device, the cylinder liner sinks in a high-temperature portion, causing gas leakage, the effect of the bead stopper being lost, and the bead breaking due to excessive force being applied to the bead, There was a problem that the cylinder head gasket was damaged due to interference with the end of the step caused by the sinking. In a conventional gasket having a pair of upper and lower substrates and a spacer interposed therebetween, a surface pressure is generated over the entire spacer portion to increase the surface pressure of the bead, and the cylinder head and the cylinder block are driven by the operation of the engine. Has the effect of suppressing the vibration of the cylinder liner, but has the disadvantage that the surface pressure generated only by the spacer is absolutely low and the force for holding down the cylinder liner is weak. If the thickness of the spacer is increased in order to increase the surface pressure, the surface pressure of the entire spacer part will increase in the opposite direction, causing bore deformation, increasing engine oil consumption, and reducing the frictional resistance of the piston. There was a disadvantage that it increased.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the first aspect of the present invention described in claim 1 is that an interposition is provided between a cylinder block having a cylinder bore formed by a cylinder liner press-fitted into a through hole and a cylinder head. A first gasket substrate located on the upper surface side, a second gasket substrate located on the lower surface side, an inner plate interposed between the two gasket substrates, and the inner plate and the second gasket substrate. And a spacer interposed between the gasket substrate and the gasket substrate, the inner plate and the spacer are laminated to form an integral body, and a required portion of the laminate is punched in accordance with the position of the cylinder bore. Equipped with a plurality of combustion chamber holes,
An annular step surrounding the combustion chamber hole and bulging downward or upward is formed at a position on the inner plate above the cylinder liner, and an outer step surrounding the annular step is formed. The above-mentioned spacer is arranged on the side where the annular step is projected, and the place where the annular step is provided is defined as a low surface pressure part, and the place where the spacer is provided is defined as a high surface pressure part. A cylinder head gasket is provided. According to a second aspect of the present invention, there is provided a cylinder head gasket interposed between a cylinder block and a cylinder head having a cylinder bore formed by a cylinder liner pressed into a through hole,
A first gasket substrate located on the upper surface side, a second gasket substrate located on the lower surface side, and a spacer interposed between the two gasket substrates, and the two gasket substrates and the spacer are laminated and integrated. A plurality of combustion chamber holes are formed at required positions of the laminate in accordance with the positions of the cylinder bores, and at least one of the gasket substrates on the upper side of the cylinder liner, An annular step portion surrounding the combustion chamber hole and swelling downward or upward is formed, and at an outer side surrounding the annular step portion and at a location on the projecting side of the annular step portion. A cylinder head gasket in which the spacer is disposed and the portion where the annular step is provided is a low surface pressure portion, and the portion where the spacer is provided is a high surface pressure portion. It is to provide a door. According to a third aspect of the present invention, there is provided a cylinder head gasket interposed between a cylinder block and a cylinder head having a cylinder bore formed by a cylinder liner press-fitted into a through hole, and is located on an upper surface side. A first gasket substrate, a second gasket substrate located on the lower surface side, and a spacer interposed between the two gasket substrates; and the two gasket substrates and the spacer are laminated and integrally formed. A plurality of combustion chamber holes perforated in accordance with the position of the cylinder bore are provided at required positions of the laminate, and further, at least one of the gasket substrates on the upper side of the cylinder liner, from the combustion chamber hole. An annular step is formed continuously on the outer side surrounding it, and the outer step surrounding the annular step is On the side and above the cylinder block, the spacer is arranged, the place where the annular step is provided is defined as a low surface pressure part, and the place where the spacer is provided is defined as a high surface pressure part. A cylinder head gasket is provided.

According to the first to third aspects of the present invention, in the initial stage, the cylinder liner portion and the cylinder block portion can be designed to some extent independently of each other. The shape of the part (height, rising angle, width of the annular step) can be set to the appropriate value for each of the cylinder liner and cylinder block parts, and therefore, sufficient sealing performance against irregularities on the upper end surface of the cylinder liner , And the degree of freedom in design is increased, so that it can be applied to various types of engines. During operation, the low surface pressure portion provided on the cylinder liner presses the upper end surface of the cylinder liner with an appropriate force (surface pressure),
As well as preventing the cylinder liner from sinking,
The protrusion of the cylinder liner during cooling can be prevented. Also, this low surface pressure part functions as a primary seal, and the high surface pressure part provided outside the cylinder liner is
Since it functions as a secondary seal and can perform multiple seals, even if gas leaks from the low surface pressure part as the primary seal part, it is completely eliminated by the high surface pressure part which is the secondary seal part. Can be sealed. Therefore, it is possible to provide a cylinder head gasket having better sealing performance than the conventional one.

[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. As shown in FIG. 2, the cylinder block 2 of the engine to which the cylinder head gasket 1 of this embodiment is applied has through holes 2 corresponding to the number of pistons.
A is formed, and a cylindrical cylinder liner 3 is press-fitted into each of the through holes 2A. That is, the engine to which the cylinder head gasket 1 of this embodiment is applied is based on the premise that the cylinder bore 4 is constituted by the inside of the cylinder liner 3. 1 and 2,
The cylinder head gasket 1 of this embodiment has a first gasket substrate 5 located on the upper surface side (upper side) and a second gasket substrate 6 located on the lower surface side (lower side), and an inner plate interposed therebetween. 7 and a spacer 8 superposed on the lower surface of the inner plate 7. The gasket substrates 5, 6 and the inner plate 7 and the spacer 8 are integrally connected to each other at a position of a water hole 11 to be described later by a conventionally known connecting means (for example, a lance lock or the like) to form a laminate. . The laminated body may be formed by welding the spacer 8 and the inner plate 7 and connecting the inner plate 7 to the gasket substrates 5 and 6 at the positions of the water holes 11 with a lance lock or the like. If necessary, a rubber layer may be provided on at least one of the surfaces of the gasket substrates 5 and 6 and the inner plate 7. As is well known in the art, the cylinder head gasket 1 is interposed between the lower cylinder block 2 and an upper cylinder head (not shown) to integrally connect the cylinder head and the cylinder block 2 with fastening bolts. As a result, they are sandwiched between them to seal between them. As described above, the cylinder liners 3 are press-fitted into the plurality of through holes 2A formed in the cylinder block 2, and the cylinder liners 3 form the cylinder bores 4, respectively. As shown in FIG. 1, the gasket substrates 5 and 6, the inner plate 7 and the spacer 8 have
Four combustion chamber holes 12 drilled in accordance with the cylinder bores 4 of the cylinder block 2, a plurality of bolt holes 13 through which fastening bolts (not shown) are passed, and a plurality of water holes 11 through which cooling water flows. Has formed.

The inner plate 7 is made of Zn having the same thickness over the entire area.
The spacer 8 is made of a relatively soft SUS material (for example, SUS304) having the same thickness over the entire area. In the present embodiment, this spacer 8 is
Is superposed on the lower surface of the inner plate 7, so that the lower surface of the inner plate 7 and the second gasket substrate 6 are sandwiched. By changing the thickness of the inner plate 7,
The thickness of the entire cylinder head gasket 1 can be adjusted. The hardness of the inner plate 7 is Hv90.
About 230, and the hardness of the spacer 8 is Hv17.
About 0 to 270 is preferable. Further, the inner plate 7 of the present embodiment is formed with an annular stepped portion 7A that surrounds the combustion chamber hole 12 and protrudes toward the lower surface. Annular step 7
The cross-sectional shape of A is formed in a flat U-shape. The width (radial dimension) D1 of the annular step 7A is set to 1.20 mm with respect to the width 2.40 mm of the cylinder liner 3, and the annular step 7A swells downward. The bulging amount is a dimension (0.1 mm) that is higher than the thickness of the spacer 8.
1 mm). The width of the annular step 7A is
The width is preferably set to about 30 to 70% of the width of the cylinder liner 3, and more preferably to about 50%. In this embodiment, the position where the annular step 7A is formed on the inner plate 7 is adjusted to be above the upper end surface 3A of the cylinder liner 3. Next, both gasket substrates 5 and 6 in the present embodiment are made of SUS having a relatively hard and springy property, having the same thickness over the entire area.
(For example, SUS301).
The gasket substrate 5 is formed with a full bead portion 5A having an arc-shaped cross section which bulges toward the lower surface surrounding the combustion chamber hole 12 and the annular step portion 7A of the inner plate 7. The hardness of both gasket substrates 5 and 6 is preferably about Hv 350 to 500.

The second gasket substrate 6 also has a full bead having an arc-shaped cross section which bulges toward the upper surface side (the lower surface side of the spacer 8) surrounding the combustion chamber hole 12 and the annular step 7A of the inner plate 7. The portion 6A is formed. In this embodiment, the full bead portions 5A and 6A are formed on the outer side of the annular step portion 7A and above the upper surface 2B of the cylinder block 2. The width (the left-right dimension in the drawing) and the amount of bulging of both full bead portions 5A and 6A are set to be the same. The width of both full bead portions 5A and 6A is set to 2.60 mm, and the bulging amount of both full bead portions 5A and 6A is set to 0.18 mm. Further, a full bead portion 5A is formed from the peripheral portion of the combustion chamber hole 12.
And the dimension from the peripheral edge of the combustion chamber hole 12 to the top 6A 'of the full bead portion 6A are set to the same size. In the present embodiment, the full bead portions 5A and 6A are formed at positions above the upper surface 2B of the cylinder block 2 deviated from positions above the cylinder liner 3. The width of the full bead portions 5A and 6A may be about twice as large as the width D1 of the annular step 7A, and is preferably set to about 1.40 to 3.50 mm. More preferably, it is 1.80 to 2.80 mm. In addition, the swelling amount of both full bead portions 5A and 6A is 0.5.
It is preferable to set the thickness to about 09 to 0.30 mm. Further, the width and the swelling amount of both full bead portions 5A and 6A are not necessarily required to be the same size, and needless to say, these dimensions may be set as needed. Also,
The edge 8A of the hole surrounding the combustion chamber hole 12 in the spacer 8 surrounds the annular stepped portion 7A and is located on the outer side in the vicinity thereof. That is, in the present embodiment, the spacer 8 is disposed at a position on the lower surface of the inner plate 7 outside the annular step 7A, and the outer edge 8B of the spacer 8 is 6 is located outside the full bead portion 6A. Therefore, this spacer 8
Is sandwiched between the lower surface of the inner plate 7 and the top 6A ′ of the full bead portion 6A of the second gasket substrate 6. The thickness of the spacer 8 is set to a size smaller than the amount of protrusion of the annular step portion 7A downward. Further, when the cylinder head gasket 1 of this embodiment is interposed between the cylinder block 2 and the cylinder head and they are connected, as shown in FIG. As the surface pressure decreases,
The surface pressure is increased at the inner and outer edge portions of the full bead portions 5A and 6A. In the present embodiment, a portion where the surface pressure is reduced by the annular step portion 7A is defined as a low surface pressure portion, while a portion which becomes the inner and outer edges of the full bead portions 5A and 6A is defined as a high surface pressure portion. As can be understood from FIG. 3, the surface pressure of the low surface pressure part (surface pressure in the area of 7A).
Is lower than the surface pressure of the high surface pressure portion (the surface pressure of the inner and outer edges of both full bead portions 5A and 6A), but the distribution range of the low surface pressure portion is smaller than that of the high surface pressure portion in the radial direction of the cylinder bore. I try to be wider. Further, in the present embodiment, the spacer 8 is provided over a region extending from a position outside the vicinity of the annular step portion 7A to the outside of the full bead portions 5A and 6A. As a result, in the cylinder head gasket 1 according to the present embodiment, as shown in FIG. 3, the area where the spacers 8 are arranged is more uniform by a predetermined amount than the area on the outer side of the spacers 8. The surface pressure is configured to be high.

When the cylinder head gasket 1 constructed as described above is interposed between the cylinder head and the cylinder block 2 and integrally connected by fastening bolts, the full bead portions 5A and 6A are compressed and deformed in the vertical direction. It has become. The top 5A 'of the full bead portion 5A is in close contact with the upper surface of the inner plate 7, the top 6A' of the full bead portion 6A is in close contact with the lower surface of the spacer 8, and the upper surface of the spacer 8 is in close contact with the lower surface of the inner plate 7. It has become. That is, the spacer 8 is provided with the annular stepped portion 7.
A is sandwiched between the lower surface of the inner plate 7 on the outer side of A and the top 6A 'of the full bead portion 6A. Further, the lower surface of the annular step portion 7A is in close contact with the upper surface of the lower second gasket substrate 6. Then, the upper surface of the first gasket substrate 5 is in close contact with the lower surface on the cylinder head side,
The lower surface of the gasket substrate 6 is the upper surface 2 of the cylinder block 2.
B and the upper end surface 3A of the cylinder liner 3. As described above, in the present embodiment, the portion where the annular step portion 7A as the low surface pressure portion is provided serves as a primary seal, and the portion serving as the high surface pressure portion functions as a secondary seal and a tertiary seal. Thus, multiple seal portions surrounding the combustion chamber holes 12 are formed. In this way, the seal between the cylinder head and the cylinder block 2 is maintained by the cylinder head gasket 1. Further, in a state where the cylinder head gasket 1 is interposed between the cylinder head and the cylinder block 2 as described above, as shown in FIG. Pressure portion), that is, the surface pressure at a position above the cylinder liner 3 is lower than the surface pressure at the inner and outer edge portions (high surface pressure portions) of both full bead portions 5A and 6A. . In a region where the spacer 8 is provided at the position of the full beads 5A and 6A, the spacer 8
The surface pressure is uniformly higher than the inner and outer regions by a predetermined amount. Further, in this embodiment, since the lower side of the annular step 7A is not covered with the spacer 8, the width of the annular step 7A as the low surface pressure part, the downward swelling amount, the rising angle and the inner plate The surface pressure of the annular stepped portion 7A as a low surface pressure portion can be adjusted by appropriately changing the material and strength of 7.

In such a cylinder head gasket 1 of the present embodiment, in the initial stage, the part above the cylinder liner 3 and the part above the cylinder block 2 are designed to some extent independently. Therefore, the surface pressure and the shape (the height of the step and the bead, the rising angle, and the width) of the cylinder head gasket 1 can be set to appropriate values for the cylinder liner 3 and the cylinder block 2 respectively. As a result, sufficient sealing performance can be ensured even for the unevenness of the upper end surface 3A of the cylinder liner 3, and the degree of freedom in design is increased.
It can support various types of engines. During operation, the position of the annular stepped portion 7A as a low surface pressure portion provided on the cylinder liner 3 presses the upper end surface of the cylinder liner 3 with an appropriate force, so that the cylinder liner 3 is inserted into the through hole 2A. To prevent the cylinder liner 3 from protruding (lifting) during engine cooling.
Further, since the low surface pressure portion functions as a primary seal and the high surface pressure portion functions as a secondary seal and a tertiary seal, even if gas leaks from the low surface pressure portion as the primary seal portion. It can be completely sealed by a high surface pressure part as a secondary seal part and a tertiary seal part. Therefore, it is possible to provide the cylinder head gasket 1 having better sealing performance as compared with the related art.
Further, the cylinder head gasket 1 of the present embodiment has the annular stepped portion 7A as the low surface pressure portion formed above the upper end surface 3A of the cylinder liner 3, so that the cylinder head and the cylinder block 2 are separated. When connected, the surface pressure of the annular step 7A is reduced. for that reason,
When the cylinder head and the cylinder block 2 are connected, the upper end surface 3A of the cylinder liner 3 is larger than the conventional one.
The contact pressure acting on the surface is reduced. Therefore, when the cylinder head and the cylinder block 2 are connected, it is possible to suppress the cylinder liner 3 from sinking in the through hole 2A. That is, when the cylinder head and the cylinder block 2 are connected, it is possible to suppress the occurrence of a step between the upper end surface of the cylinder liner 3 and the upper end portion of the through hole 2A. Thus, the cylinder head gasket 1 having good sealing properties can be provided. Furthermore, in the present embodiment, the spacer 8 is disposed outside the annular step 7A without covering the lower part of the annular step 7A, and therefore, as shown in FIG. When connected to the block 2, the surface pressure can be increased more uniformly in the region where the spacer 8 is provided than in the regions on the inner side and the outer side. Thereby, the surface pressure of both bead portions 5A and 6A can be increased. Further, since the spacer 8 does not cover the lower part of the annular step 7A and is located outside the annular step 7A, the spacer 8 is in close contact with the upper surface of the second gasket substrate 6. It functions as a stopper when doing so. Therefore, it is possible to favorably prevent the annular stepped portion 7A from being excessively compressed and deformed. In the first embodiment, the annular step 7A of the inner plate 7 is swelled downward, and the spacer 8 is arranged on the side of the swelling direction of the annular step 7A of the inner plate 7. Causes the annular stepped portion 7A to bulge upward, and the spacer 8
May be arranged on the upper surface side of the inner plate 7. That is, this configuration has a cross-sectional shape in which the cylinder head gasket 1 shown in FIG. 2 is turned upside down. Even with the cylinder head blanket 1 having such a configuration, the same operation and effect as those of the above-described first embodiment can be obtained.

(Second Embodiment) Next, FIG. 4 shows a second embodiment of the present invention.
It shows an example. In the second embodiment, the bulging directions of the full bead portions 5A and 6A provided on the gasket substrates 5 and 6 are reversed from those in the first embodiment. That is, the full bead portion 5 of the first gasket substrate 5
A bulges toward the upper surface side, and the full bead portion 6A of the second gasket substrate 6 bulges toward the lower surface side. Other configurations are the same as those in the first embodiment.
The description of those components is omitted. Even with such a configuration of the second embodiment, the same operation and effect as those of the first embodiment can be obtained.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
It shows an example. This third embodiment is based on the configuration of the first embodiment and assumes that both gasket substrates 5, 6
The half bead portions 5C and 6C are formed at outer positions adjacent to the full bead portions 5A and 6A. The half bead portion 5C of the first gasket substrate 5 is formed such that an outer edge thereof is lower than an inner edge thereof.
The half bead portion 6C of the second gasket substrate 6 is formed such that its outer edge is higher than its inner edge. Other configurations are the same as those of the first embodiment, and the description of those configurations will be omitted. Third such
Even with the configuration of the embodiment, the same operation and effect as those of the first embodiment can be obtained.

(Fourth Embodiment) FIG. 6 shows a fourth embodiment of the present invention.
It shows an example. In the fourth embodiment, the bulging direction of the full bead portion 5A of the first gasket substrate 5 in the first embodiment shown in FIG. 2 is reversed from that in FIG.
That is, the full bead portion 5A of the first gasket substrate 5 in the fourth embodiment is formed so as to bulge toward the upper surface side. Other configurations are the same as those of the first embodiment, and the description of those configurations will be omitted. Even with the configuration of the fourth embodiment, the same operation and effect as those of the first embodiment can be obtained.

Next, FIGS. 7 and 8 show a fifth embodiment and a sixth embodiment of the present invention. In these embodiments, the inner plate 7 in the embodiment of FIG. Is omitted, and an annular step corresponding to the annular step 7A is formed on the first gasket substrate 5 (fifth embodiment). That is, in the fifth embodiment shown in FIG.
An annular step 5D radially spaced from the combustion chamber hole 12 and surrounding the combustion chamber case 12 and bulging downwardly to the first gasket substrate 5 is formed. Further, a spacer 8 is arranged on the outer side of the annular step 7A. The sectional shape of the annular step 5D is the same as the annular step 7A of the first embodiment.
It is formed in a flat U-shape in the same manner as described above. In the fifth embodiment, since the inner plate 7 in the first embodiment is omitted, the spacer 8 is sandwiched between the top portions 5A 'and 6A' of the full bead portions 5A and 6A. The other configurations of the gasket substrates 5 and 6 are the same as those of the first gasket substrate 5 and 6 described above.
This is the same as the embodiment. Even in such a fifth embodiment, the same operation and effect as those of the above-described embodiments can be obtained. The annular step 5D may be bulged upward.

In the sixth embodiment shown in FIG. 8, a portion on the outer side adjacent to the combustion chamber hole 12 is
Are formed to protrude downward to form an annular step 5D. Although the cross-sectional shape of the annular step portion 5D in the fifth embodiment shown in FIG. 7 is a flat U-shape,
The cross-sectional shape of the annular step portion 5D in the sixth embodiment is such that the portion on the side of the combustion chamber hole 12 is horizontal, and the adjacent outer portion has a step having a step on the full bead side. Also, in the sixth embodiment, the first
Since the inner plate 7 in the embodiment is omitted, the spacers 8 are provided at the top portions 5A ', 6A of the full bead portions 5A, 6A.
A 'holds it. The other configurations of the gasket substrates 5 and 6 are the same as those of the first embodiment. Even in such a sixth embodiment, the same operation and effect as those of the above-described embodiments can be obtained. The cross-sectional shape of the annular step portion 5D may be a cross-section having a step such that the portion on the combustion chamber hole 12 side is horizontal and the adjacent outer portion is lower on the full bead side.

[0016]

As described above, according to the present invention, it is possible to provide a cylinder head gasket having better sealing performance than the conventional one.

[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 view showing a distribution state of surface pressure when the cylinder head gasket shown in FIG. 2 is interposed between a cylinder block and a cylinder head.

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

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

FIG. 6 is a sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a sectional view showing a fifth embodiment of the present invention.

FIG. 8 is a sectional view showing a sixth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder head gasket 2 ... Cylinder block 2A ... Through-hole 3 ... Cylinder liner 5 ... First gasket board 5A ... Full bead part 6 ... Second gasket board 6A ... Full bead part 7 ... Inner plate 7A ... Annular step part 5D ... Annular step Part 8: Spacer 12: Combustion chamber hole

Claims (10)

[Claims] 1. A cylinder head gasket interposed between a cylinder block and a cylinder head having a cylinder bore formed by a cylinder liner press-fitted into a through hole, comprising: a first gasket substrate located on an upper surface side; A second gasket substrate, an inner plate interposed between the two gasket substrates, and a spacer interposed between the inner plate and the second gasket substrate; And a plurality of combustion chamber holes that are formed integrally with each other by laminating the spacers and spacers, and are provided at required positions of the laminated body at positions corresponding to the positions of the cylinder bores, and are provided on the inner plate above the cylinder liner. Where a circular step is formed surrounding the combustion chamber hole and bulging downward or upward. In both cases, the spacer is arranged at a position on the outer side surrounding the annular step and on the side of the protrusion of the annular step, and the place where the annular step is provided is a low surface pressure part,
A cylinder head gasket, wherein a portion where the spacer is provided is a high surface pressure portion. 2. The gasket substrate according to claim 1, further comprising a full bead at a position surrounding the annular step and above the cylinder block, wherein a portion where the full bead is provided is the high surface pressure portion. The cylinder head gasket according to claim 1, wherein 3. The full bead portion of the first gasket substrate is formed so as to protrude toward the lower surface, and the full bead portion of the second gasket substrate is formed so as to protrude toward the upper surface. The cylinder head gasket according to claim 2, characterized in that: 4. The cylinder head gasket according to claim 3, wherein a half bead portion is formed at an outer position adjacent to each full bead on both gasket substrates. 5. The full bead portion of the first gasket substrate is formed so as to protrude toward the upper surface, and the full bead portion of the second gasket substrate is formed so as to protrude toward the lower surface. The cylinder head gasket according to claim 2, characterized in that: 6. The full bead portion of the first gasket substrate is formed so as to protrude toward the upper surface, and the full bead portion of the second gasket substrate is formed so as to protrude toward the upper surface. The cylinder head gasket according to claim 2, characterized in that: 7. A cylinder head gasket interposed between a cylinder block having a cylinder bore formed by a cylinder liner press-fitted into a through hole and a cylinder head, wherein a first gasket substrate located on an upper surface side and a first gasket substrate on a lower surface side A second gasket substrate and a spacer interposed between the two gasket substrates, and the two gasket substrates and the spacer are laminated and integrally formed, and the cylinder bore is provided at a required position of the laminate. A plurality of combustion chamber holes perforated in accordance with the position, and further, at least one of the gasket substrates at a position above the cylinder liner, surrounding the combustion chamber hole and at the lower side or the upper side. And forming an annular step bulging toward the outer side surrounding the annular step and The portion which becomes the protruding side of Jodan portion by disposing the spacer, together with the Teimen pressure section a portion provided with the annular step,
A cylinder head gasket, wherein a portion where the spacer is provided is a high surface pressure portion. 8. A cylinder head gasket interposed between a cylinder block having a cylinder bore formed by a cylinder liner press-fitted into a through hole and a cylinder head, wherein a first gasket substrate located on the upper surface side and a first gasket substrate on the lower surface side A second gasket substrate, and a spacer interposed between the two gasket substrates. The two gasket substrates and the spacer are laminated and integrally formed, and the cylinder bore is formed at a required position of the laminate. A plurality of combustion chamber holes perforated in accordance with the position, and at least one of the gasket substrates on the upper side of the cylinder liner, the outer side surrounding the cylinder liner continuously from the combustion chamber hole. The annular step is formed on the outer side surrounding the annular step and the cylinder block is formed. Tsu by placing the spacer on the portion which becomes the upper side of the click, with the Teimen pressure section a portion provided with the annular step,
A cylinder head gasket, wherein a portion where the spacer is provided is a high surface pressure portion. 9. The cylinder head gasket according to claim 7, wherein said gasket substrates have a full bead at a position surrounding said annular step and above a cylinder block. . 10. The cylinder head gasket according to claim 1, wherein a cross-sectional shape of the annular step portion is formed in a flat U-shape.