| 摘要 |
A power-shift gearbox unit (1) for tractors comprises two hydraulically-operated friction power-shift clutches (11, 12) associated with the gears of two different speed ratios (8, 9) and including a single drum (13) formed with two opposing thrust chambers (23, 24) for operating two pistons (21, 22) for clamping the friction discs (15, 17; 16, 18) of the two clutches. The hub (14) of the drum (13) is provided with a resilient device (25) for compensating for the axial thrusts applied to the two pistons (21, 22) by the pressure produced in the respective thrust chambers (23, 24) by centrifugal action. |
