Patent ID: 6173687
Filing Date: 2001-01-16
Classification: F01L

Abstract:
A hydraulic apparatus for adjusting the timing of opening and closing of an engine valve comprising:a cam shaft driven to rotate in synchronization with engine rotation;an actuator installed on said cam shaft for changing said timing of opening and closing of a valve using a control of a working oil supply to change said timing of opening and closing of the intake valve and/or the exhaust valve;a slidable, nontapered plunger disposed in said actuator;a rotor, having an engaging hole therein, which is disposed in said actuator and is operative to engage with said plunger by said engaging hole; anda spring to urge said plunger to move into said engaging hole to make an engagement therebetween when the engine is stopped,and when the engine begins to run, said working oil is supplied into said engaging hole to push out said plunger from said engaging hole to release the engagement between a housing of said actuator and said rotor;wherein said engaging hole and said plunger have a surface parallel with a slide direction of said plunger, and a clearance therebetween is smaller than 0.17 mm to prevent a hunting of said rotor when said engaging hole and said plunger engage each other.