Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal between parts of internal combustion engine
Reexamination Certificate
2002-07-12
2004-11-09
Pickard, Alison (Department: 3676)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal between parts of internal combustion engine
C277S594000
Reexamination Certificate
active
06814357
ABSTRACT:
The present disclosure relates to the subject matter disclosed in German application No. 101 48 295.7 of Sep. 29, 2001, European application No. 01 128 978.2 of Dec. 6, 2001, German application No. 102 17 526.8 of Apr. 19, 2002 and European application No. 02 012 148.9 of Jun. 1, 2002, which are incorporated herein by reference in their entirety and for all purposes.
BACKGROUND OF THE INVENTION
The invention relates to a cylinder head gasket with a gasket plate having at least one combustion chamber opening and comprising at least two sheet metal layers, a first one of which is provided with at least one bead which is elastically deformable in its height and encloses the combustion chamber opening, and a second one of which is provided with at least one deformation delimiting device delimiting deformation of the bead, surrounding the combustion chamber opening and lying close to the bead in a plan view of the gasket plate. Such a deformation delimiting device is usually and for that reason partly also referred to in the following as stopper.
In the case of single-layer or multilayer metallic cylinder head gaskets it has so far been customary, in order to produce a stopper radially inside or outside (with respect to the combustion chamber opening) of the bead carrying out a sealing function, to increase the thickness of a sheet metal layer in an area enclosing the combustion chamber opening in the shape of a circular ring by a flat metallic ring being attached (for example, by welding) to this sheet metal layer or by an edge area of the sheet metal layer surrounding the combustion chamber opening being flanged, i.e., folded over through approximately 180°.
Such a stopper has at least almost no elastic properties, and, in most cases, also at least almost no plastic properties, in any case under the pressure forces exerted on the stopper during operation of the engine.
Single-layer or multilayer metallic cylinder head gaskets have recently been proposed (WO 98/28559 and DE-U-298 04 534), wherein the stopper is to a considerable extent plastically and/or elastically, preferably predominantly elastically deformable under the pressure forces acting on the stopper during operation of the engine and is designed in one of the following ways: The sheet metal layer provided with the stopper is provided radially within the bead carrying out the sealing function and requiring protection (with respect to the combustion chamber opening) with one or several beads forming the stopper, enclosing the combustion chamber opening in the shape of a ring and extending concentrically with the combustion chamber opening, and in the event that there are several beads, these can project alternately in one or the other direction of the axis of the combustion chamber opening (see FIGS. 12A and 12B of WO 98/28559). Alternatively, the stopper is formed by a series of ribs and grooves following one another alternately in the radial direction, enclosing the combustion chamber opening in the shape of a ring and being provided on both sides of the sheet metal layer, with the ribs projecting above the two main surfaces of the sheet metal layer and thus resulting in a thickening of the sheet metal layer in the area of the stopper, each rib on the one side of the sheet metal layer having located directly opposite it a rib on the other side of the sheet metal layer (the same then applies to the grooves), and the ribs and grooves having been produced by flow pressing of the sheet metal layer (FIG. 12E of WO 98/28559 and DE-U-298 04 534).
These stoppers are easier to manufacture than stoppers attached to a sheet metal layer or produced by flanging a sheet metal layer, as it is possible for a sheet metal layer provided with beads to be punched out and provided with the beads in a single tool and for a sheet metal layer to be punched out and provided with the above-described ribs and grooves with a single tool. On the other hand, the recently proposed stoppers have a serious disadvantage:
The fundamental purpose of a stopper is to protect the bead at least mainly carrying out the sealing function against excessive deformations during operation of the engine, a purpose which can only be fulfilled in a highly inadequate way by a stopper which is elastically and/or plastically deformable to a considerable extent during operation of the engine. If the stopper is formed by a bead enclosing the combustion chamber opening in the shape of a circular ring or by several such beads arranged concentrically with each other, the cylinder head gasket clamped between engine block and cylinder head is unable to offer any considerable resistance to the flattening of the beads (not taking into account the stiffness of the beads), as a displacement (in the radial direction with respect to the combustion chamber opening) of the area of the sheet metal layer surrounding the combustion chamber opening, which occurs along with the flattening of the beads forming the stopper, cannot be prevented in these known cylinder head gaskets.
In the earlier German patent application No. 101 48 295.7 of Sep. 29, 2001 (from which U.S. Ser. No. 10/052 468 filed Jan. 23, 2002 claims priority) of the company ElringKlinger AG, single-layer or multilayer metallic cylinder head gaskets are described with reference to FIGS. 1-16, in which a stopper formed in a sheet metal layer forms in a plan view of this sheet metal layer a two-dimensional pattern of discrete, knob-like elevations which have been produced in a deep-draw tool. The deep-draw tool comprises a male die with a pattern of pin-shaped stamps and a female die with a corresponding pattern of openings or recesses into which the elevations forming the stopper are pressed during the deep-drawing of the sheet metal layer. In this stopper each elevation thus has a depression lying directly opposite it on the other side of the sheet metal layer.
The object underlying the present invention is to produce an at least substantially metallic cylinder head gasket wherein when manufacturing the device for delimiting the deformation (stopper) the attaching of a metal ring or the flanging of a sheet metal layer can likewise be dispensed with, but wherein the device for delimiting the deformation can fulfill its purpose, namely that of preventing excessive deformation or flattening of a bead carrying out the sealing during operation of the engine, even better than the above-described known stoppers consisting of one or several beads or ribs and grooves concentrically enclosing the combustion chamber opening, or a deformation delimiting device made up of a pattern of elevations of a sheet metal layer which are produced in a deep-draw tool.
SUMMARY OF THE INVENTION
Departing from a cylinder head gasket of the kind mentioned at the outset, wherein the deformation delimiting device is formed by such a plastic deformation of the second sheet metal layer that the latter has in at least one of its main surfaces in the area of the deformation delimiting device a pattern of stamped depressions with which elevations formed by material of the second sheet metal layer displaced during the stamping of the depressions are associated, with the total thickness of the second sheet metal layer in the area of the deformation delimiting device being greater than the original thickness of the second sheet metal layer in an area of this sheet metal layer adjoining the deformation delimiting device, this object is accomplished in accordance with the invention in that the initial, i.e., original, second sheet metal layer is formed by a steel sheet which is plastically deformable by flow pressing, in particular, by cold flow pressing, and in a plan view of the second sheet metal layer the deformation delimiting device forms a two-dimensional pattern of discrete, cup-like depressions, with the total volume of the depressions stamped by cold flow pressing being approximately equal to the total volume of the elevations which are formed by the material of the second sheet metal layer displaced during the stamping of the depressions and are associa
Diez Armin
Fritz Wolfgang
Gruhler Tobias
Schmauder Karl
ElringKlinger AG
Patel Vishal
Pickard Alison
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