1.17 HYDRAULIC PROPULSION MOTOR.

TM 5-3895-373-34 1.17 HYDRAULIC PROPULSION MOTOR. The paving machine uses two hydraulic propulsion motors. A separate motor is used for the right and left side. The left motor is powered by the left hydraulic propulsion pump and the right motor is powered by the right hydraulic propulsion pump. The following description applies to either motor. The hydraulic propulsion motor is a bent axis, piston type, high torque, variable speed, bi-directional motor. It has a maximum displacement of 3.05 cubic inches (49,98 ml) and a minimum displacement of 1.13 cubic inches (18,52 ml) per revolution. Operating pressure is 5000 psi (34 475 kPa). The charge pump in the left propulsion pump provides flow and pressure, 350 psi (2413 kPa), to the high speed shift valve. The high speed shift valve controls the paving speed and travel speed of the propulsion motors. Oil flow through the high speed shift valve positions the motor control piston. The control piston is linked by a shaft to the cylinder block and sets the angle at which the cylinder block turns. The greater the angle of the cylinder block, the slower the motor turns; the lesser the angle, the greater the speed output. The cylinder block contains seven pistons. Each piston applies force, through a connecting rod, to the drive shaft output flange causing the output flange to rotate. High pressure oil forces the pistons out, which causes a downward rotation on the output flange. Rotation of the output flange produces a rotation of the output drive shaft. Meanwhile, pistons on the opposite side of the flange are retracting, forcing the oil out at low pressure, back to the reservoir. The propulsion motors are cooled by controlled fluid leakage. A three-way, pressure driven, flushing valve allows heated hydraulic oil to exit the system and return to the hydraulic reservoir. 1.18 SPEED REDUCTION GEARBOX. The speed reduction gearbox links the hydraulic propulsion motors to the track hubs and drive sprocket gears. There is one reduction gearbox for each track. The reduction gearbox is a triple-stage unit with a reduction ratio of 65:6:1 and a continuous operating torque of 4700 lb-ft (6372 N•m). 1-9