Variable valve open-and-closure timing changing apparatus for internal combustion engine

Abstract

In a valve open-and-closure timing changing apparatus for an internal combustion engine, a rotary body ( ) is revolved in synchronization with a revolution of the engine, a camshaft ( ) is provided, and a valve open-and-closure changing mechanism is interposed between the rotary body and the camshaft to relatively rotate the camshaft to the rotary body to enable a change in a valve open-and-closure timing of at least one of intake and exhaust valves. The valve open-and-closure mechanism includes: a housing member ( ) to be revolved together with the rotary body; a vane rotor relatively rotatably housed within the housing member, to be revolved together with the camshaft, and having at least one vane radially projected therefrom; at least one pair of advance angle and retardation angle chambers partitioned between the housing member and vane rotor by means of the vane; a hydraulic supply-and-draining device that supplies a working oil into either one of the pair of the advance angle or retardation angle chamber while draining the working oil from the other of the pair of the chambers to achieve a relative rotation between the housing member and vane rotor; and a boss portion projected from one axial direction of the vane rotor toward an outside of the housing member or extended at the same position thereof.