초록 ▼

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 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.

대표청구항 ▼

A hydrostatic vehicle drive system comprising, a front hydrostatic drive circuit including a front variable displacement pump, dual displacement front wheel motors, a flow limiting valve limiting the flow to each of said front wheel motors to assure drive on both front wheel motors, a rear hydrostat

A hydrostatic vehicle drive system comprising, a front hydrostatic drive circuit including a front variable displacement pump, dual displacement front wheel motors, a flow limiting valve limiting the flow to each of said front wheel motors to assure drive on both front wheel motors, a rear hydrostatic drive circuit including a rear variable displacement pump, dual displacement rear wheel motors, a flow limiting valve limiting the flow to each of said rear wheel motors to assure drive on both rear wheel motors, a common drive for simultaneously driving said pumps, a hydraulic servocontrol valve controlling the displacement of the variable displacement pumps, a reservoir supplying hydraulic fluid to the said variable displacement pumps, a hydraulic selector valve for selectively selecting the displacement of said front and rear wheel motors, a return flow circuit for said pumps providing a source of pressurizing fluid for said servocontrol valve and said selector valve, said hydraulic servocontrol valve and said hydraulic selector valve connected to said return flow circuit for selectively controlling displacement of said variable displacement pumps and displacement of said motors to provide four wheel drive in two speed ranges and infinite speed over each range of the drive system.