The invention relates to a crankshaft bearing for an internal combustion engine including a bearing base portion integrally formed with the crankcase and a bearing cover mounted thereon, and including an insert of a material having a small heat expansion coefficient.
DE 195 45 000 C1 discloses a crankshaft bearing in a crankcase of an internal combustion engine having several bearing blocks each of which comprises a bearing base portion integrally formed with the crankcase and a bearing cover mounted on the bearing base portion. The crankshaft is received between the bearing base portion and the bearing cover. The bearing base portion and the bearing cover both consist of a light metal alloy such that they have a relatively low weight, but high strength and rigidity. The bearing cover includes an insert, which extends around the crankshaft and consists of an iron-metallic material, which has a low heat expansion coefficient as compared to the light metal alloy whereby the hot bearing play normally occurring in the area of the crankshaft bearing is reduced. The insert of iron metal which is cast into the bearing cover has a high heat conductivity and transfers the friction heat generated in the bearing in the area of the bearing blocks to the surrounding light metal housing. Because of the firm interconnection between insert and bearing cover, temperature stresses are generated in the bearing cover and the insert as a result of the different heat expansion coefficients of light metal and iron metal. The crankshaft bearing can be negatively affected thereby. In the worst case, the temperature stresses may lead to a failure of a component.
It is the object of the present invention to provide a crankshaft bearing, which has a low weight and high rigidity such that bearing play variations resulting from heat expansions are minimized. It is another object of the invention to reduce the noise generated by an engine.