(1) Can realize continuously variable speed, Convenient commutation;
(2) When the engine works at any scheduled speed, the transmission system can exert greater traction;
(3) The transmission system can maintain high efficiency in a wide output speed range;
(4) The walking power and the power of the working device can be reasonably matched to make the engine power fully utilized;
(5) The position of the hydraulic pump and the hydraulic motor is more flexible, and the engine can be arranged horizontally, which shortens the longitudinal length of the loader and improves the driver's vision ;
(6) Hydraulic pumps and hydraulic motors can be controlled by electric proportional variable. Taking into account the rapid development of microcomputer technology, the two are well combined to realize intelligent control;
(7) According to relevant information, it is related to hydraulic machinery. Compared with the transmission, the loader operation rate can be increased by 30% , Fuel consumption can be reduced by 25 %.
Wheel loader travel driving load changes greatly, its hydrostatic transmission device is composed of a variable pump and a variable motor to form a closed loop. The variable control method of the hydraulic pump is hydraulic control related to the speed. This variable method enables the loader to have the function of a torque converter and has the following characteristics:
(1) Its control pump is directly connected to the engine. There is no control valve in the variable mechanism. When the engine speed changes, the output flow of the pump is controlled. It changes accordingly, so that the change in the flow rate at the internal throttling through the control leads to a change in the pressure difference before and after throttling, which results in a change in control pressure. Speed increase-control pressure increases-displacement becomes larger;
(2) When the operating pressure of the walking drive system increases, causing the engine speed to drop, the control pressure decreases at this time, so that the pump displacement decreases, and the input torque of the pump at this time And the engine speed is restored to the set value;
(3) The control valve is linked with the engine's throttle control lever. When the engine's throttle is increased, the throttle opening in the control valve is also increased, which can obtain different driving speeds. Control curves, these control curves are parallel to each other. Once the working conditions change, make the speed change value as small as possible;
(4) can change the throttle opening in the control valve when the engine speed is adjusted, thereby increasing or decreasing the control pressure to adjust the driving speed .