Patent ID: 7246587

Claim:
A deactivating element for a valve train of an internal combustion engine, said deactivating element comprising a housing and an inner element that is axially displaceable in a bore of the housing and is biased through a lost motion spring in a direction leading out of the bore, at least one piston extending in a radial bore of the inner element, a first flattened region starting from a radially outer front end of the piston being arranged on a first axial side of the piston, for coupling the inner element to the housing in a relative position, said first flattened region can be displaced partially onto a flat entraining surface of an annular groove of the bore of the housing, at least one passage extending through the housing for supplying hydraulic medium to the annular groove, and the piston being adapted to be re-displaced into the radial bore of the inner element by the hydraulic medium, wherein a second flattened region starting from the axially outer front end of the piston and situated opposite the first flattened region is arranged on a second axial side of the piston opposite the first axial side of the piston, and a height of the annular groove in the housing is reduced by a measure not larger than a height of the second flattened region.