Patent ID: 7913657
Filing Date: 2011-03-29
Classification: F01L,Y10T

Abstract:
1. A variable valve timing mechanism, in which: a valve-lifting cam member is fitted, slidably in the circumferential direction, onto a camshaft that is driven to rotate in synchronization with a crankshaft of a four-cycle internal combustion engine; an eccentric collar is set between a driving collar fixed on the camshaft and the valve-lifting cam member; a linkage mechanism includes the eccentric collar, a driving projection formed in the driving collar and engaging with one of sandwiching portions of the eccentric collar, and a driven protrusion formed in the valve-lifting cam member and engaging with another one of the sandwiching portions of the eccentric collar; with the linkage mechanism, the torque of the driving collar is transmitted to the valve-lifting cam member; and the timing of opening and closing the valve is adjusted by making the rotational phase of the valve-lifting cam member be cyclically varied relative to the camshaft by the eccentricity of the eccentric collar, the variable valve timing mechanism comprising a key provided between the camshaft and the driving collar and used to fix the driving collar onto the camshaft, wherein the key is provided so as to partially overlap the driving projection, thus enabling the key to receive a moment that acts on a base portion of the driving projection of the driving collar.