US 9,803,685 B2 · Crankshaft

Abstract

It is common for crankshafts of internal combustion engines to have main bearing journals provided between each of the conrod bearing journals. However, to reduce engine friction, the fewest main bearing journals that can be used while still meeting the design targets is preferred. A crankshaft for an in-line, four-cylinder engine, according to an embodiment of the disclosure, has three main bearing journals. Bridges, one each located between first and second conrod bearing journals and between third and fourth conrod bearing journals. The bridges have a cross-section with at least two concavities to improve the strength of the bridge compared to, for example, a cylindrical bridge, without greatly increasing the mass of material used in the bridge. Furthermore, a locus of a centroid of cross sections through the bridge are not coincident with an axis of rotation of the crankshaft, but instead is displaced toward the nearer conrod bearing journal.

Claims20

Dependent claims

A crankshaft, comprising:

first and second main bearing journals;
first and second conrod bearing journals located between the first and second main bearing journals;
and
a bridge located between the first and second conrod bearing journals wherein an outer surface of the bridge has at least two concavities.

1 more element

Dependencies are inferred from the claim text.

Crankshaft

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Crankshaft

Life of this patent

Abstract

Claims20