Patent ID: 6273041
Filing Date: 2001-08-14
Classification: F01L

Abstract:
Cam follower (1) in a valve train of an internal combustion engine switchable between different lifts for at least one gas-exchange valve and having the following characteristics:the cam follower (1) includes a first section (2) which can be acted upon by at least one cam with a large lift and a second section (4) which is contacted by a cam with a small lift or by no cam, the second section (4) having a side away from the cam for contact with a gas-exchange valve and being capable of relative axial movement with respect to the first section (2);the first and second sections (2,4) possess cavities (8,9) aligned with each other in a cam base-circle phase, movable coupling means (15) in at least one of the cavities (8,9), the coupling means being positioned completely in the one cavity (8,9) in the decoupled state of the first section from the second section (2,4);the coupling means (15) being shiftable in a coupling direction by hydraulic fluid which can be delivered via an inlet (22) to a pressure chamber (20) formed by the one cavity (8,9) in front of an end wall (17) of the coupling means facing the pressure chamber (20), the coupling means being shiftable for coupling of the first with the second section (2,4) across a separating surface (19) between the sections (2,4) such that part of the coupling means engages in the other adjoining cavity (9,8); andshut-off means (14) face the coupling means (15);characterized by the following features:the shut-off means (14) comprising a mechanically closable and openable shut-off slide for the inlet (22) to the pressure chamber (20), the slide, being maintainable hydraulically in an open position via high switching pressure.