Variable valve operating device for internal combustion engine

Abstract

In a variable valve operating device for an internal combustion engine, which is capable of changing operation characteristics of an engine valve in accordance with a change in rotation speed of a camshaft, a high-speed cam () including a base circle portion which has the same radius as that of a base circle portion of a low-speed cam () and also including a high-level portion which has a protruding amount larger than that of a high-level portion of the low-speed cam () is supported on a camshaft (A) having the low-speed cam () fixed thereto such that the high-speed cam () is rotatable relative to the camshaft (A), at a position adjacent to the low-speed cam (); a cam follower member () is supported by an engine main body () to be operable in a manner following one of the low-speed cam () and the high-speed cam (); and a centrifugal clutch (A) configured to connect the high-speed cam () to the camshaft (A) while synchronizing the phase of the high-speed cam () with that of the low-speed cam () when the rotation speed of the camshaft (A) reaches or exceeds a predetermined rotation speed is provided between the camshaft (A) and the high-speed cam (). Accordingly, it is possible to change operation characteristics of an engine valve with a simple and compact structure.