Patent ID: 8011336

Claim:
A variable valve opening property internal combustion engine, comprising: an engine valve provided in a combustion chamber at least partly defined by a cylinder head of the engine and biased in a valve closing direction by a valve spring; a rocker arm pivotally supported by the cylinder head and having a tip portion contacting a valve stem of the engine valve for opening the engine valve, the tip portion being disposed intermediate a pivotally supported proximal base portion of the rocker arm and a distal free end arm portion of the rocker arm; a camshaft rotatably supported by the cylinder head and carrying a cam; a roller link including a cam engaging part configured to engage the cam and a rocker arm engaging part engaging a slipper surface of the rocker arm, and adjustably supported by the cylinder head for a guided motion of the cam engaging part; a control link for adjusting a trajectory of the guided motion of the cam engaging part; an actuator for actuating the control link; and a spring device mounted on the cylinder head and provided with a pressure surface that acts upon a spring engaging part of the roller link so as to bias the cam engaging part against the cam; wherein the pressure surface extends by a prescribed distance so as to accommodate a guided movement of the spring engaging part caused by an adjustment of the trajectory of the guided motion of the cam engaging part by the control link.