Patent ID: 8187142

Claim:
Bevel friction ring gear mechanism having at least two friction cones ( 2 , 3 ; 102 ) which are arranged spaced apart from one another, and having a friction ring ( 4 ) which is arranged displaceably in said spacing ( 5 ) along friction faces ( 10 , 11 ; 110 ) on the friction cones ( 2 , 3 ; 102 ), and transmitting a torque from one of the two friction cones ( 2 , 3 ; 102 ) to the other of the two friction cones ( 2 , 3 ; 102 ), the friction ring ( 4 ) encompassing a first of the two cones ( 2 ) and at least one friction face varying axially, wherein the axial variation of the friction face ( 10 , 11 ; 110 ) has a radius (C 1 , C 2 , C 3 ) above 0.1 mm in at least two convex regions ( 143 , 153 ) and a radius above 0.01 mm in at least two concave regions ( 19 , 26 ; 119 , 126 ), the friction ring ( 4 ) in cooperation with one of the friction cones ( 2 , 3 ; 102 ) always covering at least two or more raised portions ( 142 , 152 ) of one of the friction faces ( 10 , 11 ; 110 ).