Gasket and a method for the manufacture thereof

Details Gasket and a method for the manufacture thereof Gasket and a method for the manufacture thereof

2001-05-04

2004-02-10

Knight, Anthony (Department: 3676)

Seal for a joint or juncture

Seal between fixed parts or static contact against...

Contact seal between parts of internal combustion engine

C277S592000, C277S593000, C277S627000, C277S639000

Reexamination Certificate

active

06688606

ABSTRACT:

FIELD OF THE INVENTION
The present invention is related to gaskets, for example flat metal gaskets suitable for usage in internal combustion engines, wherein the gaskets comprise at least one metal layer, the metal layer having one or several openings in accordance with the number and location of combustion chambers and, if present, coolant and lubricant passageways of the internal combustion engine. Furthermore, the invention concerns a method for manufacturing gaskets according to the invention.
BACKGROUND OF THE INVENTION
In order to form protrusions for providing sealing lines, gaskets having one or several layers frequently include metal rings which are located around the combustion chamber openings of a layer. Among other things, the protrusions formed by the metal rings pursue the object to protect—when the gasket is installed, in particular at high combustion pressures and the “beating” of the cylinder head resulting therein—depressions located for providing additional sealing lines in one or several sheet metal layers from being completely flattened and thus functionally limited or even destroyed. Metal rings which have such a depression based protective function within a flat metal gasket are known as “deformation limiters”, “spring way limiters” or “stoppers”, as well.
Among other things, stopper rings have so far been attached to certain layers of the flat metal gasket by spot welding. In the gaskets according to U.S. Pat. No. 6,053,503, the attachment is made by continuous laser welding. Along with the relatively high expenditure during manufacture, both welding and soldering, as it is suggested in this context in patent DE 195 36 718-A1, show the disadvantage that the achievable height of the protrusion is almost exclusively determined by the metal sheet thickness of the applied metal ring. Furthermore, the resulting joint is rigid. If plastic or elastic, respectively, characteristics are desired for the stopper, for example to achieve a certain attenuation of the “beatings”, additional constructional measures concerning the metal layers or the metal ring, respectively, have to be taken, as for example forming additional depressions in these structural members.
As a way of attaching a ring which serves as a protrusion, U.S. Pat. No. 5,863,046 discloses welding, gluing or the like. In this case too, the height of the protrusion is only determined by the used metal ring. Furthermore, the obtained joint does per se not have any additional plastic, plastic/elastic or elastic characteristics, or at least none worth to be mentioned, in the stopper region of the gasket.
In the patents EP-0 797 029-A1 and in the DE 198 29 058-A1, stoppers manufactured on the basis of thermosetting plastics are described, the thermosetting plastics additionally containing mineral or metal filling material. In contrast to metal ring stoppers, such stoppers show—depending on their composition depending on their composition—plastic, plastic/elastic or elastic characteristics. In particular the stoppers according to patent DE 198 29 058-A1 show good results as they have among other things advantageous thermal conduction characteristics due to their content of metal filling materials, which is an advantage in case large amounts of heat have to be transported. Nevertheless, certain limitations with respect to their applicability in internal combustion engines with very high requirements as for the thermal resistibility of the gasket exist. Furthermore, plastic and filling material have to be selected carefully and mated with each other for each application, since the operating conditions of modern engines in some cases can reach the consistency limits of materials which are used for the above-discussed plastic stoppers containing filling material.
SUMMARY OF THE INVENTION
The present invention provides a gasket comprising at least one metal layer having at least one opening therethrough and a metal ring located around said opening, the metal ring being laminated to the metal layer by a plastic layer, wherein the plastic layer is formed, such that it provides the gasket in the region of the metal ring with a physical characteristic selected from the list of plastic, plastic/elastic and elastic.
Compared to known gaskets with stoppers manufactured on the basis of thermosetting plastics, joining a metal ring and a metal layer of the gasket over a plastic layer according to the claim surprisingly results in an increased temperature resistibility of the obtained protrusion. At the same time, one effect of the usage of the metal ring is that the selection of the constituency of the plastic layer is less critical for a certain application and that the number of possibilities of applying one fixed plastic composition is increased, which is advantageous during manufacture.
Furthermore, by selecting the layer thickness of the plastic layer, in particular in case plastic masses having a high content of filling material are applied, varying requirements to the protrusion to be obtained can be fulfilled in an easy and quick manner without the necessity of applying or keeping on stock, respectively, metal rings of different thicknesses.
Gaskets according to the invention may comprise one or several metal layers (depending on the embodiment, those are also called single-layer, dual-layer or multi-layer sealing constructions). The metal layers may be metal sheets which have openings in accordance with the number and location of the combustion chambers of the internal combustion engine to be sealed and, if necessary, the coolant and lubricant passageways.
Around the combustion chamber opening(s) of the metal layer of at least one of the metal layers in case of dual- or multi-layer flat gaskets), a metal ring is laminated (that is located on the surface), the ring and the layer being connected over a plastic layer. The plastic layer is formed in a way that it provides the gasket in the region of the metal ring with plastic, plastic/elastic or elastic characteristics. This does not exclude that in the region of the metal ring by taking constructional measures, the metal ring itself or other structural members of the gasket are provided with further means which result in plastic, plastic/elastic or elastic characteristics, for example depressions (circular or trapezoidal depressions), edge projections, right-angle bands and the like. Moreover, the formation providing the plastic layer with plastic, plastic/elastic or elastic characteristics can—according to the invention—be limited to certain zones in the region of the metal ring, for example to the region which is not directly adjacent to the cylinder screws. Preferably, the plastic layer of the gasket, however, provides the whole region of the metal ring, that is its complete circumference, with plastic, plastic/elastic or elastic characteristics.
In order to provide the region of the metal ring with plastic, plastic/elastic or elastic characteristics, the plastic layer has to have a certain thickness in this region, wherein the thickness exceeds the usual thickness of plastic layers which are only used for joining or gluing together, respectively, to structural members of the gasket, but which do not considerably contribute to the thickness of certain gasket zones. Accordingly, the plastic layers in gaskets according to the invention preferably have a thickness of at least 5 &mgr;m, more preferably 5-150 &mgr;m, in particular 5-100 &mgr;m and especially preferred 10-50 &mgr;m in zones where they provide the gasket with plastic, plastic/elastic or elastic characteristics.
Moreover, the ratio of the plastic layer thickness to the sheet metal thickness of the metal ring, the latter being joined to the metal layer over a plastic layer is preferably within a range of 1:100 to 2:1, particularly within a range of 1:30 to 1:1, and especially preferred within a range of 1:15 to 1:1.
Taking into consideration the characteristics of compositions used for the plastic layer or the filling material composition (substance and size) contained therein, a person skilled in the

Affiliated with

Also associated with

Rating

Gasket and a method for the manufacture thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Gasket and a method for the manufacture thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gasket and a method for the manufacture thereof will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3345866