HYDRAULIC DRIVE SYSTEM FOR A VEHICLE

摘要

HYDRAULIC DRIVE SYSTEM FOR A VEHICLE A hydrostatic drive system having a closed loop front wheel drive circuit and a closed loop rear wheel drive circuit. A variable displacement pump in each of the circuits is cammed to vary the displacement delivered to dual displacement wheel motors to provide two speed ranges for the drive system. A servosystem uses hydraulic fluid to cam the displacement of the variable displacement pump and a hydraulic control to selectively engage each of the drive ranges.