JP2003239802A - Metallic gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a cooling effect in a periphery of a combustion chamber hole, and provide superior sealing performance. <P>SOLUTION: The metallic gasket is provided with a plurality of combustion chamber holes 13, a bead 14 provided so as to surround the plurality of combustion chamber holes 13, and water holes 17b arranged in predetermined portions between mutually adjacent combustion chamber holes 13. By thickening inner circumferential rim parts A of the combustion chamber holes 13, providing a thickness difference to other portions, and concentrating a bearing pressure on the inner circumferential rim parts A when the metallic gasket is interposed between faying surfaces of a cylinder head and a cylinder block and it is clamped by a clamping bolt, a part between the faying surfaces is sealed. The water holes 17b are arranged in an inner side of the bead 14, a water passage 27 is formed in a space between each inner circumferential rim part A of mutually adjacent combustion chamber holes 13, and the water passage 27 is communicated with the water holes 17b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket which is interposed between the joint surfaces of a cylinder block and a cylinder head constituting an internal combustion engine and seals the joint surfaces.

[0002]

2. Description of the Related Art As a conventional metal gasket of this type, for example, the end of the substrate on the side of the combustion chamber hole is folded back, or a ring-shaped shim plate is attached to the end of the substrate on the side of the combustion chamber hole. When the inner peripheral edge of the hole is made thicker than the other parts to create a plate thickness difference, and the plate thickness difference causes the plate to be interposed between the joint surfaces of the cylinder head and the cylinder block and tightened with fastening bolts. It is known that the surface pressure is concentrated on the inner peripheral edge portion of the combustion chamber hole, whereby a maximum load is applied to the inner peripheral edge portion of the combustion chamber hole under severe sealing conditions to seal between the joint surfaces. There is.

[0003]

In recent engines, the so-called all-aluminum construction has led to a reduction in weight, size, and higher output, resulting in a narrower space between cylinders (combustion chamber holes) and a higher heat load. Therefore, the water hole jacket tends to be arranged as close as possible to the combustion chamber hole to enhance the cooling effect of the engine.

By the way, as a method of further enhancing the cooling effect of the engine, it is conceivable that a cooling water flow groove is formed in the joint surface between the bores of the cylinder block and the flow groove is communicated with the water hole jacket. However, when the flow grooves are formed between the bores of the cylinder block in this manner, the space between the cylinders is narrow as described above, so that the sealing area by the inner peripheral edge of the combustion chamber hole of the metal gasket cannot be sufficiently secured. It is difficult to obtain excellent sealing performance, and the rigidity between the bores is reduced due to the flow groove, which reduces the rigidity due to the use of all-aluminum and limits the sealing surface pressure at the inner peripheral edge of the combustion chamber hole. is there.

The present invention has been made in order to eliminate such inconvenience, and provides a metal gasket which can enhance the cooling effect around the combustion chamber holes and can obtain excellent sealing performance. The purpose is to

[0006]

In order to achieve the above object, the invention according to claim 1 has a plurality of combustion chamber holes, a bead provided so as to surround the plurality of combustion chamber holes, and A cylinder head by providing a water hole arranged at a predetermined position between the adjacent combustion chamber holes, and thickening an inner peripheral edge portion of the combustion chamber hole to provide a plate thickness difference with other portions. When interposing between the joint surfaces with the cylinder block and tightening with fastening bolts, the surface pressure is concentrated on the inner peripheral edge portion of the combustion chamber hole, whereby a maximum load is applied to the inner peripheral edge portion and the space between the joint surfaces is increased. A metal gasket that seals the water holes inside the bead and forms water passages in the spaces between the inner peripheral edge portions of the combustion chamber holes that are adjacent to each other. The passage is communicated with the water hole.

A metal gasket according to a second aspect is the metal gasket according to the first aspect, wherein at least two metal plates are provided, and one of the metal plates is thickened at an inner peripheral edge portion of the combustion chamber hole. 4. A plate thickness difference is provided between the metal plate and another portion, and the end of the remaining metal plate on the side of the combustion chamber hole is cut to arrange the water hole inside the end. The invention according to claim 1 is characterized in that, in claim 1 or 2, the total plate thickness of the inner peripheral edge portion of the combustion chamber hole is thin near the bolt insertion hole of the fastening bolt,
The space between the bolt insertion holes is made thicker, and is varied along the circumferential direction of the combustion chamber hole.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view for explaining a metal gasket which is an example of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line BB of FIG. 1, and FIG. 3 is a sectional view taken along the line AA of FIG. 4 to 11 are explanatory sectional views for explaining a metal gasket which is another embodiment of the present invention.

A metal gasket which is an example of an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The metal gasket 10 includes a metal plate, a substrate 11, and a substrate 11.
And a sub plate 12 made of a metal plate having substantially the same thickness, and a plurality of combustion chamber holes 13 are formed in the substrate 11 so as to correspond to the ends of the cylinder bores. Combustion chamber hole 13 of substrate 11
The end portion on the side is double-folded downward to form the thickest inner peripheral edge portion A, which provides a plate thickness difference with other portions. Further, the end portion of the auxiliary plate 12 on the combustion chamber hole 13 side is cut and arranged outside the inner peripheral edge portion A.

A full bead 14 is provided on the substrate 11 and the sub plate 12 around the inner peripheral edge portion A.
Is formed by curving, and the full bead 15 is formed by curving the substrate 11 and the sub plate 12 on the outer peripheral portion. Each full bead 14 provided on the substrate 11 and the sub-plate 12 is a side (outside) where the recesses 14a are separated from each other.
Similarly, each full bead 15 provided on the substrate 11 and the sub-plate 12 is also provided with its concave portion 15a facing away from each other (outer side).

Full bead 14 of substrate 11 and sub-plate 12
Between the full bead 15 and the full bead 15, a plurality of bolt insertion holes 16 of the fastening bolt are formed at substantially equal intervals in the circumferential direction, and water holes 17 a and oil holes 18 are formed between the bolt insertion holes 16. Further, water holes 17b smaller than the water holes 17a are formed between the combustion chamber holes 13 adjacent to each other, and the full beads 14, 15 are formed.
It is arranged on the inner side (combustion chamber hole side) and on the inner side (combustion chamber hole side) from the cut end of the auxiliary plate 12 on the combustion chamber hole 13 side.

Bolt insertion hole 1 in substrate 11 and sub plate 12
6, a full bead 19a is provided around the substrate 6 and the sub-plate 1.
2 is formed by curving, and the full bead 19b is also formed around the oil hole 18 by curving the substrate 11 and the sub plate 12. Each full bead 19a provided on the substrate 11 and the sub plate 12 is provided with its recessed portion (not shown) facing away from each other (outside), and each full bead 19b provided on the substrate 11 and the sub plate 12 is also provided. Similarly, the recesses (not shown) are arranged so as to face away from each other (outside).

A shim plate made of a metal plate having substantially the same thickness as that of the substrate 11 is provided between the substrate 11 and the sub plate 12 in a portion located between the full beads 14 and 15 (hereinafter referred to as an intermediate portion B). 21 is interposed, and the shim plate 21 is attached to the substrate 11 by welding or the like. The shim plate 21 is formed with bolt insertion holes 16, water holes 17a, and oil holes 18 for fastening bolts, similar to the substrate 11 and the sub plate 12.

Further, the inner peripheral edge portion A of the substrate 11 has a thin portion 22 near the bolt insertion holes 16 and a thick portion 23 between the bolt insertion holes 16 so that the combustion chamber hole 13 is circumferentially formed. The plate thickness is changed along the line A, and the total plate thickness of the thin portion 22 of the inner peripheral edge portion A is larger than the total plate thickness of the intermediate portion B. In addition, full beads 14,1
In each of the concave portions 14a, 15a of 5, for example, fluororubber, N
An elastic sealing material 24 such as a rubber material such as BR or silicon rubber or a resin material is filled. These recesses 14a, 1
The filling amount of the elastic sealing material 24 filled in 5a is substantially the same as the volume in the recesses 14a, 15a, and is substantially flush with the flat surfaces of the substrate 11 and the sub-plate 12.

In order to prevent fretting caused by the difference in thermal expansion between the cylinder head and the cylinder block, the entire surface including the recesses 14a, 15a of the full beads 14, 15 on the outer surface side of the substrate 11 and the sub-plate 12 has a second flow. A lubricant such as molybdenum oxide is applied. Also, the substrate 1
1. All or a part of the sub plate 12 and the shim plate 21 are metal-plated or resin-plated on the entire surface including the cut surface of the metal plate, thereby preventing corrosion of the metal gasket and long-term. A good sealing performance is ensured throughout.

Then, the metal gasket 10 having such a structure.
Is interposed between the joining surfaces of the cylinder block 25 and the cylinder head 26 and tightened with fastening bolts, the full beads 14, the full beads 15, the full beads 19a, and the full beads 19b are compressed and deformed in the plate thickness direction, and at the end of tightening, Due to the difference in the plate thickness between the inner peripheral edge A of the combustion chamber hole 13 of the substrate 11 having the largest plate thickness and other portions, the surface pressure is most concentrated on the inner peripheral edge A and a maximum load acts, whereby the above Maximum surface pressure at inner peripheral edge A and full bead (including elastic seal material) 1
A triple seal is created by the repulsive force of 4,15,
The stopper effect of the inner peripheral edge portion A and the intermediate portion B prevents the full bead 14 from fully bending, and the stopper effect of the intermediate portion B prevents the full bead 15, the full bead 19a, and the full bead 19b from fully bending.

At this time, a water passage 27 is formed in the space between the inner peripheral edge portions A between the combustion chamber holes 13 adjacent to each other, as shown in FIG. Here, since the water hole 17b is located inside the cut ends on the side of the full beads 14 and 15 and the combustion chamber hole 13, the water passage 27 has the water hole 17b.
The cooling water flows to the water passage 27 in communication with b, and the cooling water flows along the joint surface of the cylinder block 25 and the surface of the substrate 11 on the cylinder head 26 side.
It is possible to further enhance the cooling effect in the vicinity of the engine bore (combustion chamber hole 13) to which a high heat load is applied.

Further, as in the conventional case, the cylinder block 2
Since it is not necessary to form a flow groove between the bores of No. 5, it is possible to secure a sealing area by the thick inner peripheral edge portion A of the combustion chamber hole 13, and it is possible to avoid a decrease in rigidity due to the formation of the flow groove. It is possible to obtain excellent sealing performance. Further, the concave portions 14a, 1 of the full beads 14, 15
Since the elastic sealing material 24 is filled in the 5a, the repulsive force of the full beads 14 and 15 and the elastic repulsive force of the elastic sealing material 24 filled in the recesses 14a and 15a of the full beads 14 and 15 synergize with each other. The necessary sealing pressure can be easily secured.

Further, full beads 14, 15, 19a, 1
Since each of the concave portions 9b is filled with the elastic sealing material 24, the elastic sealing material 24 can satisfactorily seal the scratches on the joint surface and the casting holes within the width of the concave portion with the elastic sealing material 24. . Further, since the elastic sealing material 24 is covered with the full bead, it is not affected by the external environment, and as a result, deterioration is prevented and stable sealing performance can be secured for a long period of time.

Further, in the inner peripheral edge portion A of the substrate 11, the thin portion 22 is formed near the bolt insertion hole 16 and the thick portion 23 is formed between the respective bolt insertion holes 16. The repulsive force of the inner peripheral edge portion A is weak in the vicinity of the fastening bolt having a large tightening force, and is strong between the fastening bolts having a relatively small tightening force, and as a result, the surface pressure acting on the inner peripheral edge portion A is evenly distributed in the circumferential direction. In addition to being able to reduce the axial force of the fastening bolt, it is possible to favorably prevent the deformation of the engine, especially the deformation of the low-rigidity engine.

The present invention is not limited to the above-mentioned embodiments, but can be modified as appropriate without departing from the gist of the present invention. For example, in the above embodiment, the case where the shim plate 21 is interposed in the intermediate portion B is taken as an example, but it is not always necessary to do so, and as shown in FIG. 4, the shim plate is provided in the intermediate portion B. Instead of interposing, the sub-plate 12 may be folded back at the position outside the full bead 15 to form the outer peripheral edge portion C having a thickness smaller than the inner peripheral edge portion A.

In the above embodiment, the water passage 2
In order to increase the cooling effect by enlarging the space of 7, the substrate 1
Although the end portion of the No. 1 on the combustion chamber hole 13 side is double-folded downward to form an inner peripheral edge portion A that is thicker than other portions, instead of this, as shown in FIG. The end portion on the side may be folded downward in a single or triple or more to form the inner peripheral edge portion A that is thicker than other portions.

Further, in the above embodiment, the end portion of the substrate 11 on the combustion chamber hole 13 side is folded back to be the inner peripheral edge portion A thicker than the other portions, but instead of this, as shown in FIG. In addition, a ring-shaped shim plate 30 may be attached to the end portion of the substrate 11 on the combustion chamber hole 13 side by welding or the like to form the inner peripheral edge portion A that is thicker than other portions, or, as shown in FIG.
The end portion of the substrate 11 on the combustion chamber hole 13 side may be folded back downward in a single layer or more, and the ring-shaped shim plate 40 may be included in the folded-back portion to form the inner peripheral edge portion A thicker than other portions.
As shown in FIG. 11, a full bead 100a or a half bead may be formed on the ring-shaped shim plate 100 included in the folded portion of the end portion on the combustion chamber hole 13 side.

Further, in the above embodiment, the case where the substrate 11 and the sub plate 12 are formed of metal plates having substantially the same plate thickness is taken as an example, but the present invention is not limited to this, and as shown in FIG. Alternatively, the sub-plate 12 that is thinner than the substrate 11 may be used. Further, as shown in FIG. 9, another sub-plate 50 is interposed between the substrate 11 and the sub-plate 12, and the end of the sub-plate 50 on the combustion chamber hole 13 side is aligned with the sub-plate 12. The shim plate 21 may be interposed between the sub plate 40 and the sub plate 12 at the position of the intermediate portion B. In this case, the shim plate 2 is provided in the middle portion B of the sub plate 40.
A step 42 that is ½ of the plate thickness of 1 is provided.

Further, in the above embodiment, the end of the sub-plate 12 on the combustion chamber hole 13 side is cut in order to flow the cooling water in the water passage 27 along the joint surface of the cylinder block 25 to enhance the cooling effect. The end portion of the sub-plate 12 on the side of the combustion chamber hole 13 is located outside the water hole 17b. Alternatively, the cooling water in the water passage 27 may be caused to flow along the surface of the sub plate 12. In this case, the notch 4 is formed in the sub plate 12.
By providing 3, the cooling water in the water passage 27 can be made to flow along the joint surface of the cylinder block 25, as in the above embodiment.

Further, in each of the above-mentioned embodiments, the elastic sealing material 24 is provided in the recesses of the full beads 14 and 15 and the metal plate 11 and
It is filled so as to be substantially flush with the flat surface of 12, but instead of this, as shown in FIG.
5 has an elastic seal member 2 having a volume substantially equal to that of the recess.
4 may be filled so that the elastic seal material 24 in the recess is compressed and deformed to be substantially flush with the flat surfaces of the metal plates 11 and 12 when tightened by the fastening bolts.

[0027]

As is apparent from the above description, in the invention of claim 1, the water passages provided between the inner peripheral edge portions of the combustion chamber holes adjacent to each other are communicated with the water holes to cool the water passages. Since the water is caused to flow, the cooling effect in the vicinity of the bore of the engine, which is subject to a high heat load, can be further enhanced.

Further, unlike the conventional case, it is not necessary to form the flow groove for flowing the cooling water between the bores of the cylinder block, so that the sealing area can be secured by the thick portion of the inner peripheral edge of the combustion chamber hole, and Since it is possible to avoid a decrease in rigidity due to the formation of the flow grooves, it is possible to obtain excellent sealing performance. According to the invention of claim 2, in addition to the invention of claim 1, since the cooling water flowing through the water passage can be made to flow directly along the joint surface, the cooling effect can be further improved.

According to the invention of claim 3, in addition to the invention of claim 1 or 2, the total plate thickness of the inner peripheral edge portion is thin in the vicinity of the bolt insertion hole having a relatively high surface pressure, and the bolt having a relatively low surface pressure. Since the space between the insertion holes is thick, the surface pressure acting on the inner peripheral edge portion when fastened with the fastening bolts can be made uniform in the circumferential direction, and the axial force of the fastening bolts can also be reduced. The effect that the deformation of the engine, especially the deformation of the low-rigidity engine can be favorably prevented can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view for explaining a metal gasket that is an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 5 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 6 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 7 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 8 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 9 is an explanatory sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 10 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

FIG. 11 is an explanatory cross-sectional view for explaining a metal gasket which is another embodiment of the present invention.

[Explanation of symbols]

10 ... Metal gasket 11 ... Substrate (metal plate) 12 ... Sub plate (metal plate) 13 ... Combustion chamber hole 14, 15 ... Full bead 16 ... Bolt insertion hole 17b ... water hole 21 ... Shim plate (metal plate) 24 ... Cylinder head 25 ... Cylinder block 27 ... Water passage A ... Inner peripheral edge

Claims (3)

[Claims] 1. A plurality of combustion chamber holes, a bead provided so as to surround the plurality of combustion chamber holes, and a water hole arranged at a predetermined position between the combustion chamber holes adjacent to each other, By increasing the thickness of the inner peripheral edge of the combustion chamber hole and providing a plate thickness difference between the combustion chamber hole and the other portion, the combustion is performed when the cylinder head and the cylinder block are interposed and fastened with a fastening bolt. A metal gasket in which surface pressure is concentrated on an inner peripheral edge of a chamber hole, whereby a maximum load is applied to the inner peripheral edge to seal between the joint surfaces, and the water hole is formed inside the bead. And a water passage is formed in a space between the inner peripheral edge portions of the combustion chamber holes that are adjacent to each other, and the water passage is communicated with the water hole. 2. At least two metal plates are provided, and an inner peripheral edge portion of the combustion chamber hole of one of the metal plates is thickened to provide a plate thickness difference with other portions. The metal gasket according to claim 1, wherein an end of the remaining metal plate on the side of the combustion chamber hole is cut to arrange the water hole inside the end. 3. The total plate thickness of the inner peripheral edge of the combustion chamber hole is varied along the circumferential direction of the combustion chamber hole by making the fastening bolt thin near the bolt insertion hole and thickening between the bolt insertion holes. The metal gasket according to claim 1, wherein the metal gasket is a metal gasket.