Change-speed gearbox

摘要

A speed-change gearbox 1 comprises a housing 2 containing a rotatable input shaft 3 connectable to a prime mover and carrying a pinion 5, a rotatable and co-axial output shaft 17 carrying a plurality of speed reduction gears 15, 16 and a plurality of lay shafts 7. Each lay shaft 7 carries a gearwheel 6 in mesh with the pinion 5 and a hydraulically operable clutch 11 through which a respective transmission gear 14 in mesh with an individual speed reduction gear 15, 16 is driven. A hydraulic pump is driven by one of the lay shafts 7 for supplying hydraulic fluid to each clutch 11. The output shaft 17 is connected to the input shaft 34 of an epicyclic reduction stage 35, a torque sensing device being connected between the annulus 41 and the housing.