Camshaft for a variable-stroke exchange valve train

Abstract

A camshaft of a sliding cam valve train in an internal combustion engine is provided. A cam piece ( 2 ), which has cam strokes of different lengths and can be displaced on a carrier shaft ( 1 ), is mounted on a rolling bearing at a camshaft bearing point ( 12 ) of the internal combustion engine. The outer race ( 16 ) of the rolling bearing ( 13 ) is formed by a one-piece bearing ring ( 17 ) which surrounds the cam piece and said race is smaller than a revolution radius of the longer stroke h 2.

1 . A camshaft of a variable stroke gas exchange valve train of an internal combustion engine, comprising a carrier shaft and a cam part that is supported locked in rotation and axially displaceable on the carrier shaft and has at least one first cam group of at least two directly adjacent cams with different strokes (h 1 , h 2 ) and an axial connecting link in which an actuation element is couplable for shifting the cam part on the carrier shaft, and a bearing journal that runs between the first cam group and the axial connecting link and on which a roller bearing supporting the cam part is held so that for rotation at a camshaft bearing point of the internal combustion engine, an inner raceway of the roller bearing is formed by the bearing journal, an outer raceway of the roller bearing is formed by a one-part bearing ring, and the cam part and the bearing ring have the following geometric properties:
   a) h 1 <h 2        b) max {r HK ; r GK +h 1 }<r L <r GK +h 2        c) r L <r AK      
       where h 1 =the stroke of the cam adjacent to the bearing journal in the first cam group, h 2 =the stroke of the other cam of the first cam group, r HK =a common enveloping circle radius of the cams of the first cam group, r GK =a base circle radius of the cams of the first cam group, r L =a radius of the outer raceway, and r AK =a circumferential radius of the axial connecting link. 
     
     
         2 . The camshaft according to  claim 1 , wherein the roller bodies of the roller bearing are held in a roller bearing cage that is open on a periphery. 
     
     
         3 . The camshaft according to  claim 2 , wherein the bearing journal has a radial step with a raised inner raceway, and at least one end sides of the radial step supports the roller bearing cage axially. 
     
     
         4 . The camshaft according to  claim 2 , wherein the cam part has a second cam group of at least two directly adjacent cams with different strokes (h 1 , h 2 ), wherein at least one end side facing each other of the cams adjacent to the bearing journal in the cam groups supports the roller bearing cage axially. 
     
     
         5 . The camshaft according to  claim 4 , wherein the cam end sides directly support the roller bearing cage axially. 
     
     
         6 . The camshaft according to  claim 4 , wherein at least one of the cam end sides supports the roller bearing cage axially by a spacer ring that is open on a periphery.