MOLDED PLASTIC CAMSHAFT WITH METAL SEAL RING

摘要

An overhead camshaft internal combustion engine having a plastic camshaft which extends through an opening on the cylinder head, the plastic camshaft havi ng a seal ring disposed around the outer surface of the molded plastic camshaft to provide an interface surface for contacting a seal assembly disposed between the engine casing and the molded plastic camshaft. The seal assembly and the seal ri ng provide a fluid tight seal to prevent leakage of fluid through the cylinder head opening. The seal ring provides a smooth contact surface for the molded plastic camshaft to prevent wear and damage to the seal assembly from the abrasive surfa ce of the molded plastic camshaft. The seal ring also provides a heat sink for dissipating the frictional heat generated by the rotation of the camshaft. In a nother form, the plastic camshaft includes a powdered metal surface formed thereon. The powdered metal surface provides the same benefits as the seal ring, namely protection from wear and dissipation of heat. The seal ring or the powdered meta l surface may advantageously be extended to include the portion of the molded plas tic camshaft in contact with a journal bearing.