Hydraulic actuator in an internal combustion engine

摘要

A hydraulic actuator including a piston connected to a camshaft. First and second passages extend through the camshaft. The piston is actuated in accordance with differences in pressure applied to the piston through the passages. A bearing rotatably supports the camshaft. The first and second passages open at the circumferential surface of the camshaft. First and second grooves are defined in the bearing and arranged at different positions with respect to the axial and circumferential directions of the camshaft. The first and second grooves are communicated with the first and second passages such that the grooves form substantially sealed hydraulic passages for carrying hydraulic fluid to or from the passages while the camshaft rotates . <IMAGE>