MOWER WITH FOUR WHEEL STEERING AND HYDRAULIC FOUR WHEEL DRIVE

摘要

A mower having a cutting deck for cutting grass has four drive wheels arranged in a square or rectangular configuration on the mower's frame. Four wheel drive and four wheel steering are employed with the drive wheels. The four wheel drive is provided by a hydraulic drive system that employs a pair of identical serial circuits which have their own pumps with each pump serially sending its output through a rear drive motor and a front drive motor that are catty-corner to one another on the frame, i.e. are on opposite sides of the motor. Various flow crossover paths and flow recirculation paths are provided in the serial circuits to ensure the drive motors receive adequate flow in maximum turns of the mower. The flow recirculation paths around a pair of drive motors at one end of the frame are shut off during reverse and during braking so that all drive motors retain hydraulic braking in these conditions.