Patent ID: 8246505

Claim:
A planetary gear unit ( 8 ), comprising: sun ( 17 ), planet ( 24 ) and ring ( 18 ) gears; a planet carrier comprising a planet bogie plate ( 19 ) and at least one planet shaft ( 20 ) on both sides ( 21 , 22 ) of the bogie plate ( 19 ); a planet wheel ( 23 , 24 ) mounted on the at least one planet shaft ( 20 ) via taper roller bearings ( 25 ); an axially displaceable piece ( 31 , 32 ) on each of extremities ( 33 , 34 ) of the at least one planet shaft ( 20 ) forming an abutment ( 35 ) which provides an axial support for inner bearing rings ( 26 , 27 ) of said taper roller bearings ( 25 ), both axially displaceable pieces ( 31 , 32 ) being formed by abutment plates ( 31 , 32 ), respectively a first abutment plate ( 31 ) and a second abutment plate ( 32 ); means for tensioning ( 36 ) by which said axially displaceable pieces ( 31 , 32 ) can be displaced toward one another for controlling pre-tensioning on the taper roller bearings ( 25 ), the means for tensioning comprising a central rod ( 38 ) which can be brought into an axial passage ( 39 ) provided in the planet shaft ( 20 ), the rod ( 38 ) being connectable to the first abutment plate ( 31 ) at a first extremity ( 40 ) of the rod ( 38 ), while the rod passes through a central hole ( 41 ) provided in the second abutment plate ( 32 ) at a second extremity ( 42 ) of the rod ( 38 ), the second extremity ( 42 ) being provided with an external thread ( 43 ) on which a nut ( 44 ) can be screwed against the second abutment plate ( 32 ); and means for locking ( 52 ) are provided by which said axially displaceable pieces ( 31 , 32 ) can be locked on the planet shaft ( 20 ) in order to prevent said axially displaceable pieces ( 31 , 32 ) from rotating with respect to the at least one planet shaft ( 20 ).