Patent ID: 8813487
Filing Date: 2014-08-26
Classification: F03C,F15B

Abstract:
1. A hydraulic wheel drive system comprising: at least one hydraulic motor adapted to drivingly rotate a vehicle wheel, said motor defining a motor cavity and including at least one piston at least partially disposed within a piston bore and moveable between an extended position and a retracted position, said piston permitting free rotation of said motor when in said retracted position; a first hydraulic pump having a selectively variable discharge; a first loop within said circuit, hydraulic fluid being recirculateable through said first loop and said first loop comprises in serial order, said first hydraulic pump, a first hydraulic line, said hydraulic motor and a second hydraulic line; a third hydraulic line providing fluid communication between said first hydraulic line and a first valve; a fourth hydraulic line providing fluid communication between said second hydraulic line and a second valve; a fifth hydraulic line providing fluid communication between said first and second valves wherein said first valve has an open position permitting bi-directional fluid communication between said third and fifth hydraulic lines and a closed position preventing fluid communication from said third hydraulic line to said fifth hydraulic line; and wherein said second valve has an open position permitting bi-directional fluid communication between said fourth and fifth hydraulic lines and a closed position preventing fluid communication from said fourth hydraulic line to said fifth hydraulic line; a second hydraulic pump; a sixth hydraulic line receiving a hydraulic fluid from said second hydraulic pump and providing fluid communication between said second hydraulic pump and a third valve; and, a seventh hydraulic line providing fluid communication between said third valve and said motor cavity wherein said third valve has a first position providing fluid communication from said sixth hydraulic line to said seventh hydraulic line and a second position preventing fluid communication from said sixth hydraulic line to said seventh hydraulic line.