JP3229360B2 - Metal 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 metal gasket interposed at a joint surface between a cylinder head and a cylinder block of an internal combustion engine to prevent leakage of combustion gas, cooling water, lubricating oil and the like.

[0002]

2. Description of the Related Art In an internal combustion engine, a sealing function is provided by fastening a metal gasket to a joint surface between a cylinder block and a cylinder head with a metal gasket interposed therebetween. In recent engines, an overhead cam (OHC) type has increased, and a chain drive is performed to link a crankshaft and a camshaft in order to rotate a camshaft provided in a cylinder head. Referring to the external view of the engine shown in FIG. 5, the engine body 50 includes a cylinder block 51 provided with a crankshaft, a chain chamber cover 52 provided in contact with the cylinder block, and a cylinder provided on the upper part thereof. Since the crankshaft in the cylinder block 51 and the camshaft (both not shown) in the cylinder head 53 are separated from each other, rotation cannot be transmitted between the gears. Are connected by a chain in the chain chamber cover. In the figure, reference numeral 54 denotes a soft gasket interposed between the cylinder head, the cylinder block and the chain chamber cover below the cylinder head.

FIG. 6 is a diagram showing the mutual relationship between the joining positions of the respective parts shown by the dotted lines in FIG. As shown in FIG. 6, the material of the cylinder block is cast iron (Fe), the material of the chain chamber cover and the cylinder head is aluminum (Al), and when these are tightened and the operation and rest are repeated, the chain has a thermal expansion difference due to each material. A gap 56 is formed above the chamber cover 52 and on the cylinder block side. The reason for this is that the knock is fixed at the crankshaft position under the cylinder block, and the chain chamber cover is fixed by the knock hole at the bottom of the chain chamber cover, so the fluctuation due to the difference in thermal expansion occurs at the top of the chain chamber cover Because you have to do it.
Therefore, in order to fill the gap 56 formed in the upper part, conventionally, as shown in FIG. 7, a thin metal plate is added to the soft gasket to partially increase the mass, and the silicon rubber 57 is printed and increased on the side surface in direct contact. I was following.

[0004]

The above-mentioned conventional soft gasket (based on asbestos, chemical fiber, and carbon) is a small and light-weight, high-performance, fuel-saving, and long-lasting engine that has been rapidly changing recently. However, satisfactory performance cannot be ensured. Therefore, recently, metal gaskets are being replaced, but there is no problem when simply replacing them with metal gaskets. As is well known, a metal gasket is a method in which a bead is provided on a substrate made of an elastic metal plate, and sealing is performed using a repulsive force of the bead with respect to a tightening force at the time of mounting. Moreover, as can be seen from the durability test, the remaining amount of the bead is 0.1 to
There is a large amount of 0.2 m / m, and there is almost no surface pressure near 0.2 m / m. Also, the difference in thermal expansion between the cylinder block made of cast iron and the chain chamber cover made of aluminum during operation and when stopped in cold air may be 0.25 m / m or more at the maximum. However, as described above, since the restoring force of the bead is 0.20 m / m at the maximum, complete sealing is also difficult in this case. Therefore, it is inevitable to partially apply rubber having good sealing properties to cope with the problem, but even this cannot withstand long-term use. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a metal gasket that can completely seal a three-point joint portion between a chain chamber cover, a cylinder block, and a cylinder head. .

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a metal gasket for an engine cylinder head in which a cylinder block and a chain case are formed separately. A metal gasket body corresponding to the upper surface of the metal gasket, wherein a quadrangular opening along the longitudinal direction of the metal gasket is formed at a three-point bonding position with the cylinder head, and a sponge is formed in the opening. A compensating plate having a material was provided.

[Action] When a step occurs due to a temperature difference at the three-point junction,
The sponge portion provided on the compensating plate in the quadrangular opening expands to fill the step and seal.

[0006]

An embodiment will be described below with reference to the drawings. FIG.
FIG. 1 is a configuration diagram of an embodiment of a metal gasket according to the present invention, which is shown as a plan view. In the figure, reference numeral 10 denotes a metal gasket main body, a dotted line vertically indicated by 11 is a cylinder block (right part), and a left part of the dotted line is a chain chamber cover part. FIG. 1 shows a metal gasket provided above a lower cylinder block and a chain chamber cover integrated therewith. That is, the portion on the right side of the dotted line 11 corresponds to the cylinder block, and the portion on the left side corresponds to the chain chamber cover. Here, reference numeral 12 denotes an opening provided corresponding to the combustion chamber hole provided in the cylinder block, and reference numeral 13 denotes an opening provided corresponding to the chain chamber cover.

Reference numeral 14 denotes a quadrangular opening provided in the metal gasket, and a dotted line 11 is provided to distinguish the left side and the right side of the cylinder block (the right side of the reference numeral 11). Here, the quadrangular portion shown at 14 covers the hole including the cylinder block portion, the chamber case portion, and the cylinder head portion. The enlarged plan view is as shown in FIG.

In FIG. 2, the symbols already described in the above description are omitted, and only those newly appearing are shown. In FIG. 2, the portion on the right side of the dotted line 11 is a cylinder block,
52 is a chain chamber cover part. As mentioned above
14 is a quadrilateral opening provided in the metal gasket,
This portion is a portion that complements between the chain chamber block 52, the cylinder block 51, and a cylinder head (not shown), and 15 is a compensating plate. The compensating plate 15 is provided in an opening provided in the metal gasket main body 10 , and is fixed to the gasket main body by eyelets 16. Here the compensator 15
In the center position, there is a core material 17 having a thickness smaller than the thickness of the metal gasket. Further, NBR and silicon rubber or fluoro rubber are applied to both surfaces of the core material, and rubber is foamed on this portion to form a sponge. This sponge includes a sponge having a core material at the center and a sponge having a thicker side on the cylinder side (the side where a step is generated).

Next, the operation will be described with reference to FIGS. Normally, as shown in FIG. 3, the sponged portions 18 on both sides of the core material 17 are within the thickness of the metal gasket body 10 , and in this case, the gap between the chain chamber cover and the cylinder head Therefore, it is within the above-mentioned thickness. Next, when the temperature reaches −30 ° C., a step x is formed between the cylinder block 51 and the chain chamber cover 52, and the cover 52 is lowered to increase the gap. In this case, the sponged portion 18 which has been within the thickness of the metal gasket expands to compensate for this portion. That is, the sponge is always protected within the thickness of the metal gasket plate, and when the stepped portion expands due to a temperature difference, the sponge is restored completely and a complete seal is secured.

[0010]

As described above, according to the present invention, an opening is formed in a metal gasket at a three-point joint position between a chain chamber cover, a cylinder block, and a cylinder head. Since a compensating plate having sponge portions on both sides of the core material is provided in the opening, even if a step is formed between the cylinder block and the chain chamber cover due to shrinkage due to heat, this portion can be sufficiently filled up. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of a metal gasket according to the present invention.

FIG. 2 is a view for explaining a compensating plate provided between a chain chamber case and a cylinder block.

FIG. 3 is a diagram illustrating an operation in a normal state where there is no temperature change.

FIG. 4 is a view for explaining the operation of the compensator when the chain chamber case is lowered compared to the cylinder block at a temperature of −30 ° C.

FIG. 5 is an external view of an engine.

FIG. 6 is a diagram showing how the bonding relationship of a portion shown by a dotted line in FIG. 5 changes with a decrease in temperature.

FIG. 7 is a diagram showing how a conventional type compensates for a gap when a temperature changes.

[Description of Signs] 10 Metal gasket main body 11 Dotted line 12 Combustion chamber hole 13 Opening 14 Quadrilateral opening 15 Compensator 16 Eyelet 17 Core material 18 Sponge part

Claims (3)

(57) [Claims] 1. A metal gasket for an engine cylinder head in which a cylinder block and a chain case are formed separately, wherein a metal gas corresponding to an upper surface of a joint between the chain chamber cover and the cylinder block.
A metal gasket, at a three-point joint position between the metal gasket and four sides along a longitudinal direction of the metal gasket;
Forming an opening having a shape and sponge in the opening.
A metal gasket comprising a compensating plate having a zigzag material . 2. The metal gasket according to claim 1, wherein the compensating plate has a core material at the center and sponge portions on both surfaces thereof. 3. The metal gasket according to claim 1, wherein the thickness of the compensator is equal to or less than the thickness of the metal gasket.