Variable valve train
AssigneeHonda Motor Co., Ltd.
InventorsYoshihiro Takada, Dai Kataoka
Life of this patent
Estimating the term…
Abstract
A variable valve train of an internal combustion engine has cylindrical cam carriers axially slidably and co-rotatably fitted on camshafts, respectively. The cam carriers have, respectively, first cam lobes and second cam lobes different in cam profile and axially adjacent to each other. Cam changeover mechanisms operate to axially shift the cam carriers to change over the first cam lobes and the second cam lobes to operate engine valves. An axial recess is formed in an axial end surface of an enlarged-diameter portion of the camshaft for axial insertion of an end of the cam carrier. The engine can thus be reduced in axial size, and a required axial shifting space for the cam carrier is secured.
Claims11
A variable valve train of an internal combustion engine, comprising:
- a camshaft rotatably supported in a cylinder head of the internal combustion engine;
- a cylindrical cam carrier fitted on and around the camshaft in a manner axially slidable relative to the camshaft but prevented from rotation relative to the camshaft, the cam carrier being formed therearound with a plurality of cam lobes different in cam profile and axially adjacent to each other;
- and
- a cam changeover mechanism including a changeover driving shaft and changeover pins for axially shifting the cam carrier to change over the cam lobes for operating an engine valve,
- wherein the camshaft has, on an axial end thereof, an enlarged-diameter portion with an axial end surface with which one end of the cam carrier around the camshaft is adapted to abut axially,
- wherein said cam carrier has therearound a lead groove cylindrical portion having therearound a lead groove, and the changeover pins are engaged with or disengaged from the lead groove to axially shift the cam carrier,
- wherein said lead groove cylindrical portion has an outer diameter smaller than an outer diameter of a base circle of the cam lobes, and
- wherein the axial end surface of the enlarged-diameter portion includes an axial recess for axially receiving an end of said lead groove cylindrical portion of the cam carrier.
Dependencies are inferred from the claim text.