Desmodromic oscillating cam actuator with hydraulic lash adjuster

Abstract

A valve actuating mechanism includes opening and closing rotary cams rotatable together about a primary axis and a rocker pivotable about a first pivot axis spaced from the primary axis. The rocker includes first and second rocker arms connected to actuate a valve by oscillating motion about the pivot axis. The first and second rocker arms respectively carry opening and closing cam followers operable by the opening and closing cams for positively oscillating the rocker in either direction. The closing cam follower has a pad engagable with the closing cam and carried by a hydraulic lash control piston slidable in a cylinder of the second rocker arm. The cylinder is connected with a pressure oil supply having a check valve preventing reverse oil flow. A bleed orifice in the pad is sized to allow restricted oil flow from the cylinder to avoid excessive loading of the mechanism. The orifice may be blocked by the cam to limit oil flow during operation of the pad on the cam base circle. The piston is advanced by the oil pressure during cam base circle operation to take up lash between the cams and cam followers.

Dependencies are inferred from the claim text.