Sliding cam system having an extended engagement region

Abstract

A sliding cam system, having at least one sliding cam, which is arranged in a rotationally fixed but axially displaceable manner on at least one axially fixed base shaft of a reciprocating-piston internal combustion engine in order to form a camshaft, at least one actuating device for moving the sliding cam into different axial positions by at least one actuating pin that can reach into at least one displacement groove on the periphery of the sliding cam. The actuating device has a machine-fixed housing and the displacement groove is formed in a top circle surface of the sliding cam down to a groove base and is helical and has an insertion region, a displacement region having an accelerating flank and a braking flank, and a retraction region for the actuating pin. An extended engagement region is associated with the displacement groove and the extended engagement region at least partially has a material removal from the level of the top circle surface in the direction of the groove base.

1 . A sliding cam system of a reciprocating-piston internal combustion engine, comprising a camshaft having at least one sliding cam, which is arranged in a manner which prevents relative rotation but allows axial shifting on at least one axially fixed base shaft in order to form the camshaft, at least one actuating device for adjusting the sliding cam into different axial positions, the at least one actuating device having at least one actuating pin that is made to engage in at least one shifting groove on a periphery of the sliding cam, the actuating device has a housing fixed to the engine and the shifting groove is machined into a top circle surface of the sliding cam down to a groove bottom and is of helical design and has an entry region, a shifting region having an accelerating flank and a braking flank, and an exit region for the actuating pin, the shifting groove has an extended engagement region and the extended engagement region at least partially has a material removal from a level of the top circle surface in a direction of the groove bottom. 
     
     
         2 . The sliding cam system as claimed in  claim 1 , wherein there are a plurality of shifting grooves and each of the shifting grooves is assigned an extended engagement region. 
     
     
         3 . The sliding cam system as claimed in  claim 1 , wherein the material removal extends as far as a level of the groove bottom. 
     
     
         4 . The sliding cam system as claimed in  claim 1 , wherein the extended engagement region corresponds to a peripheral extent of the material removal. 
     
     
         5 . A sliding cam system having two shifting grooves, which are designed as double S grooves, the extended shifting regions for the first shifting grooves amount to between about 145° and about 290° of a cam angle and the extended shifting regions for other of the shifting grooves amount to between about 75° and about 290° of a cam angle. 
     
     
         6 . The sliding cam system as claimed in  claim 1 , wherein the extended engagement regions correspond to complete sliding cam peripheries minus the shifting regions. 
     
     
         7 . The sliding cam system as claimed in  claim 1 , wherein the braking flanks of the shifting regions are offset outward into walls of the shifting grooves.