Apparatus for adjusting valve lift

Abstract

An apparatus for adjusting valve lift (VVL apparatus) is made up of a substantially cylindrical tappet casing having on an upper end thereof a cam contact portion which comes into contact with a cam which is provided on a camshaft and which has a high lift cam profile; an outer tube coaxially disposed inside the tappet casing; an inner tube coaxially disposed inside the outer tube so as to be axially slidable and circumferentially rotatable; and a helical spring which is disposed between the inner tube and the tappet casing and which constantly urges the inner tube in a direction of increasing an amount of axial displacement of an intake valve. A ramp groove with which pins of the inner tube are engaged is an arcuate groove having a curve of secondary degree. Collision noises in low lift mode are thus arranged to be adequately absorbed. Silence at a low engine speed can therefore be secured and the number of parts is reduced and the weight of the VVL apparatus is reduced.

Dependencies are inferred from the claim text.