Patent ID: 7707979

Claim:
A switchable valvetrain for an internal combustion engine, comprising: a row of rocker arms which extend in a longitudinal direction of a cylinder head, which intrinsically have, on an underside at one end, an at least indirect run-on face for at least one cam, and at an other end, a valve rest and on an upper side a recess in which a head of a bearing journal sits, with at least a subset of the bearing journal being axially moveably arranged in a corresponding bore of an above-situated carrier or of an insert part which is connected to the carrier, with each modular unit being assigned coupling means for selectively coupling the moveable bearing journal at least indirectly to the carrier, so that in a deployed state of the moveable bearing journal, a large valve lift is generated when coupled and a relatively small or zero valve lift is generated when decoupled, and with the moveable bearing journal being acted on out of the bore by means of a lost motion spring, wherein an annular groove is arranged in the bore of the carrier or the insert part, the at least axially upper annular face of which the annular groove runs orthogonally with respect to an axial line of the bore of the carrier or the insert part, with the bearing journal having at least one radially-running or secant-shaped recess which intersects an outer casing and in which, in a decoupled case, is seated at least one piston as a coupling means, which, proceeding from a radially outer face end, is of a stepped design with a flattening situated above, and which coupling means, for a coupled case, can be displaced with its flattening in sections under the upper annular face of the annular groove of the bore of the carrier or insert part, and wherein the bearing journal has a hydraulic play compensating device whose pressure piston is a constituent part of the bearing journal and has the head.