Low friction high speed rocker arm

Claim 1

A valve train for an internal combustion engine comprising, a camshaft mounted close above the cylinder head face of the engine, a one-piece essentially U-shaped rocker arm mounted above the camshaft for an arcuate movement and defined by a bottom wall integral with a pair of laterally spaced upstanding side walls, the bottom wall having a cylindrical fulcrum surface projecting upwardly therefrom, a lash adjuster fixedly supported above the rocker arm against lateral movement and having a lower surface engaging the cylindrical fulcrum surface with a contact establishing a pure rolling motion without friction of the rocker arm upon the lash adjuster lower surface, a reciprocatingly mounted valve stem engaging one end of the rocker arm for reciprocation of the valve, the other end of the rocker arm rotatably supporting a dual function roller engagable with a cam lobe on the camshaft for arcuate pivoting of the rocker arm about its fulcrum upon rotation of the camshaft, support means supporting the roller for both an arcuate movement of its axis of rotation along a predetermined path providing a pure rolling motion of the rocker arm about its fulcrum upon the lash adjuster surface and confining the roller and arm in a manner preventing longitudinal sliding movement of the rocker arm fulcrum surface relative to the lash adjuster surface.