Flat Sealing Joint Forming In Particular A Cylinder Head Gasket For An Internal-combustion Reciprocating-piston Engine

Abstract

A metal cylinder head gasket for an internal combustion piston engine, adapted to be placed between the confronting surfaces of a cylinder barrel and a cylinder head, respectively and comprising two adjacent respectively radially outer and inner annular portions covering substantially the whole confronting surface of said barrel with said cylinder head, said outer portion having a substantially smooth surface and said inner portion being relatively wider and more easily deformable than said outer portion by being clamped between said confronting engaging surfaces.

Description

The present invention relates essentially to a substantially flat packing or sealing joint forming in particular a cylinder head gasket for an internal-combustion reciprocating-piston engine and which is adapted for instance to be positioned between the engaging surfaces of a cylinder barrel, liner, sleeve or jacket and a cylinder head.

The cylinder barrel, sleeve or liner rests generally upon the edge of the cylinder water jacket with its top end or head portion by means of a collar or shoulder forming an outer flange. The cylinder head gaskets of the prior art are relatively narrow radially so as to provide a high clamping pressure between the barrel and cylinder head and are in bearing engagement with the barrel at a point radially offset or shifted inwards with respect to the bearing point of the barrel onto the water-jacket in the cylinder block or case thereby causing the occurrence of a bending moment within the barrel in view of the clamping pressure with stresses or strains that are periodically variable in operation of the engine.

A known approach provided by the prior art consists in increasing the diameter of the cylinder head gasket so as to offset the same radially outwards in order to make the same overlie the bearing point of the barrel onto the cylinder water-jacket thereby cancelling the lever arm due to said radial offset of the bearing points. As however the cylinder head gasket in spite of all remains narrow to enable the achievement of a high clamping pressure, a free space or gap is thus formed between the cylinder head and the cylinder barrel towards the inner side of said barrel. The combustion gases tend to flow into this free gap between the cylinder head and the barrel and exert high pressure forces thereon thereby causing as before the occurrence of a bending moment due to the fact that the pressure forces exerted by the combustion gases are more offset with respect to the bearing reaction of the water jacket. Moreover these combustion gases may cause carbon deposits to build up within said gap, tending to seize, stick or bond the cylinder head to the barrel, thus resulting in difficulties of disassembling or removing the cylinder head if need be. To avoid such drawbacks, there has been proposed to mount towards the inner edge of this gap a ring of some height larger than that of said gap so as to be set with its respective upper and lower edges into a pair of corresponding annular grooves of the cylinder head and barrel, respectively, thereby to serve as a barrier preventing the combustion gases from flowing into said space. This arrangement offers the inconvenience of being complicated hence expensive.

There are also known annular packings which are provided in view of the required high pressures/with concentric sealing teeth or serrations raising from the plane of the packing in the form of accumulated materials. Theses teeth or serrations however have the purpose only of increase the specific surface pressure of the packing without solving said problems.

In order to solve these problems and avoid said drawbacks, the invention proposes a flat metal sealing packing or joint member forming in particular a cylinder head gasket for an internal combustion piston engine and which is adapted to be positioned for example between the confronting surfaces of a cylinder barrel and a cylinder head, characterized in that it comprises two adjacent respectively radially outer and inner annular portions covering substantially the whole confronting surface of said barrel with said cylinder head, said outer portion having a smooth surface and said inner portion being relatively wider than said outer portion and more easily deformable by being clamped between said confronting surfaces.

According to another characterizing feature of the invention, said inner annular portion is made in one piece or integral with said outer portion and is formed on at least one of its sides with concentric or annular parallel serrations, grooves, flutes or the like.

According to still a further characterizing feature of the invention, said inner portion is of a total height at least equal to that of said outer portion and is radially corrugated, wavy or rippled.

The sealing packing according to the invention is therefore not radially offset outwards as in said prior art and enables the filling out of that space or gap left between the confronting surfaces of the barrel and cylinder head which is accessible to the combustion gases.

The invention will be better understood and further objects, characterizing features, details and advantages thereof will appear more clearly as the following explanatory description proceeds with reference to the accompanying diagrammatic drawings given by way of example only illustrating various presently preferred forms of embodiments of the invention and wherein:

FIG. 1 is a partial view in longitudinal axial section through the junction between a cylinder barrel and a cylinder head provided with the annular sealing gasket according to the invention;

FIG. 2 shows a partial top view corresponding to FIG. 1 when the cylinder head is removed;

FIG. 3 is an enlarged view showing the encircled detail III of FIG. 1; and

FIGS. 4 to 8 are views in diametral half section showing various forms of embodiment of the sealing gasket according to the invention.

On FIG. 1 has thus been shown a partial section through a cylinder barrel 1 topped by a cylinder head 2 through the medium of a sealing gasket 3 according to the invention. The cylinder barrel, liner or sleeve 1 rests upon the edge 4 of the cylinder water-jacket by a collar, shoulder or flange 5 that is provided on said sleeve. The ringshaped sealing gasket 3 according to the invention is placed onto the recessed face 8 of the top end of the cylinder barrel 1 which face is limited radially outwards by an annular shoulder 6 for centering the cylinder head. As seen in FIG. 1, the shoulder 6 lies inward radially relative to the inner surface 4b of said water jacket 4a. The cylinder head 2 comprises a complementary or mating shoulder 7 co-operating with said shoulder 6 of the barrel 1.

According to the invention, the sealing gasket 3 comprises a pair of adjacent annular respectively radially outer and inner portions 10 and 11 which cover substantially the whole annular surface 8 of the barrel. As seen in FIG. 1 the sealing packing 3 forming a cylinder head gasket is thus radially offset inwards of said barrel 1 with respect to the bearing point of this barrel 1 onto the water-jacket 4 of the cylinder.

The inner portion 11 of the sealing gasket 3 is relatively wider than the outer portion 10 and is also more easily deformable through being clamped between the cylinder head 2 and the surface 8 of the cylinder barrel 1. Thus the outer portion 10 of the gasket 3 sustains almost all of the stresses exerted by the clamping of the cylinder head against the barrel thereby enabling achievement of a very high clamping pressure and a good fluid-tightness between said cylinder head 2 and said barrel 1. The inner annular portion 11 of the sealing gasket opposes less resistance to the clamping forces and is more easily deformable and its function is mainly to prevent the combustion gases from having access to the space comprised between the surface 8 of the barrel 1 and the cylinder head 2.

Thereby is obtained a very high clamping pressure of the gasket between the barrel and the cylinder head owing to the relatively small width of the portion 10 of the gasket and the occurrence of additional bending moments within the barrel is avoided in view of the provision of the inner portion 11 of the gasket which prevents the combustion gases from flowing between the barrel and the cylinder head.

The outer annular portion 10 of the gasket is desirably formed with a smooth surface whereas the inner annular portion 11 of this gasket exhibits on at least one of its sides serrations, grooves, flutes or like formations which are of annular configuration and arranged concentrically relative to each other. The provision of serrations, grooves or like formations on the surface of the inner portion 11 makes this inner portion more deformable or yielding than the outer portion 10 which undergoes substantially the major part of the clamping force. The depth of the hollows or recesses and the height of the crests or ridges of the projections or serrations condition the clamping pressure it is desired to obtain hence the stresses which result therefrom. The serrations formed on the inner annular portion 11 also perform the function of a labyrinth joint for the combustion gases.

In FIGS. 3 to 8 have been shown various forms of embodiment of the sealing gasket according to the invention. On FIG. 3 the inner portion 11 is provided with parallel concentric annular grooves 15 on both of its sides, these grooves being desirably offset on one side with respect to that of the other side i.e. a hollow, valley or recess on one side lies substantially opposite a projection or raised portion on the other side.

On FIG. 4 the parallel concentric annular grooves 15' provided on each one of the sides of the inner portion 11 of the sealing gasket are in exact registry and in overlying relationship thereby forming a series of chokes or restricted sections within the thickness of the sealing gasket.

In an alternative embodiment shown on FIG. 5, the inner annular portion 11 of this gasket has a smaller metal thickness than the outer annular portion 10 and is radially wavy, corrugated or rippled.

In a further modification shown in FIG. 6, the inner annular portion 11 of the gasket comprises a series of annular concentric grooves 15" provided on one of its sides only. The other side of the inner annular portion 11 is thus perfectly smooth and on level or in flush relationship with the outer annular portion 10. In all of the aforesaid examples the overall height between the engaging surfaces of both opposite sides of the inner portion 11 i.e., between the tops, crests or ridges of the projections provided on these two faces is equal to or preferably slightly larger than the thickness or height of the smooth outer portion 10. Moreover both portions 10 and 11 may either form a unitary single integral piece or consist of a pair of separate annular elements.

In other forms of embodiments of the sealing gasket 3 according to the invention which are shown on FIGS. 7 and 8, said gasket is not of integral one-piece unitary homogeneous configuration but comprises a pair of distinct or separate adjacent respectively outer and inner annular portions 20 and 21 or 20' and 21'. Both annular portions forming the gasket are made from different metals, the outer annular portion 20, 20' being made from a harder metal than the inner annular portion 21, 21' which is thus made from a metal more easily deformable in compression. According to circumstances the portion 21 may be of a height slightly larger than that of portion 20 or as shown on FIG. 8, the portion 21' is of a height substantially equal to that of portion 20'.

To make in particular the inner and outer portions of the sealing gasket, metals may be selected one of which exhibits a modulus of elasticity smaller than that of the other metal.

The sealing gasket according to the invention whether it is made from homogeneous or heterogeneous material thus brings about a significant improvement in use with conventional cylinder barrels by cancelling the increase in bending moment occurring within this barrel and due to the pressure of the combustion gases during operation of the engine.

It is to be understood that the invention is not at all limited to the forms of embodiments described and shown which have been given by way of example only. In particular it comprises all the means forming technical equivalents to the means described as well as their combinations if same are carried out according to the gist of the invention.

Claims

What is claimed is:

1. An internal combustion piston engine of the type embodying at least a cylinder head, a cylinder water jacket, a cylinder barrel, and outer flange means on said barrel resting upon an edge of said cylinder water jacket, said cylinder head and said barrel having confronting surfaces in a zone located radially inwardly with respect to said outer flange means of said cylinder barrel, and the improvement comprising a gasket dimensioned to lie between said confronting surfaces and consisting of a substantially flat metal sealing packing covering substantially the whole of said confronting surfaces of said barrel with said cylinder head and said gasket consisting of a pair of adjacent respectively radially aligned outer and inner annular portions, said outer portion having a substantially smooth face, said inner portion being more easily deformable than said outer portion upon being clamped between said confronting engaging surfaces and having a greater radial width than the outer radial portion, said inner portion being further characterized in that said inner portion is provided with a series of concentric alternate grooves and projections provided on at least one of the faces of said gasket and are comprised of radially disposed flute-like formations, the crests of which are substantially flat and in substantially parallel relation to such face.

2. An internal combustion engine according to claim 1, wherein said inner portion is characterized further by being provided on both faces of said gasket with said series of concentric alternate grooves and projections.

3. An internal combustion engine according to claim 1 wherein said inner portion is characterized further by having a thickness no greater than that of said outer portion of said gasket.

4. An internal combustion piston engine of the type embodying at least a cylinder head, a cylinder water jacket, a cylinder barrel, and outer flange means on said barrel resting upon an edge of said cylinder water jacket, said cylinder head and said barrel having confronting surfaces in a zone located radially inwardly with respect to said outer flange means of said cylinder barrel, and the improvement comprising a gasket dimensioned to lie between said confronting surfaces and consisting of a substantially flat metal sealing packing covering substantially the whole of said confronting surfaces of said barrel with said cylinder head and said gasket consisting of a pair of adjacent respectively radially aligned outer and inner annular portions, said outer portion having a substantially smooth face, said inner portion being more easily deformable than said outer portion upon being clamped between said confronting engaging surfaces and having a greater radial width than the outer radial portion, said inner portion being further characterized by a series of concentric hills and crests respectively of substantially uniform height and depth.