A GEAR BOX FOR A WORKING MACHINE AND A METHOD FOR CONTROLLING A GEAR BOX

摘要

The present invention relates to a gear box (100) for a working machine (1), said gear box (100) being arranged to be positioned in a first set of speed-changing gears and a second set of speed-changing gears, wherein the gear box comprises: a gear box housing (156), an input shaft (102) configured to receive torque, and an output shaft (108) for supplying torque out from the gear box (100), wherein said output shaft (108) is connected to a planetary gear set (144) of said gear box, a friction disc clutch arrangement (152) which is arranged between a ring gear (154) of the planetary gear set (144) and the gear box housing (156) for enabling connection of the ring gear (154) to the gear box housing (156), and a control unit configured to controllably alternate said friction disc clutch arrangement between: an engaged state and an at least partially engaged state when the gear box (100) is positioned in said first set of speed-changing gears, and between a disengaged state and an at least partially engaged state when the gear box (100) is positioned in said second set of speed-changing gears. The present invention also relates to a corresponding method for controlling a gear box.