Wheel loaders are widely used as walking machines for earthwork transportation and loading, lifting and transporting loose and piled goods. On the one hand, as a tire mini wheel loader with high traction, it has great maneuverability, and on the other hand, it has the characteristics of quickly changing the working site under high-speed driving conditions. Therefore, it is a good combination of power and maneuverability, which determines its economy and practicality.

The hydrostatic travel transmission scheme (with subsequent load-shifting transmission) has a lot of advantages over the hydraulic dynamic pressure torque converter transmission scheme, and it has been successfully applied to the production of wheel loaders with a drive power of up to 60 kW.

The application of hydrostatic transmission in high-power tire loaders is similar to that of torque converter drive devices. Due to the large torque range in this type of hydrostatic transmission, an additional shifting transmission is required, which brings the disadvantage of traction interruption during the gear shifting process. Nevertheless, in tire loaders with a drive power of 60 kW to 100 kW, the travel system is gradually tending towards hydrostatic transmission.

However, in agriculture wheel loaders with engine power of up to 200 kW, unladen weight of 25,000 kg and maximum travel speed of 45 km/h, almost exclusively torque converter transmissions have been used so far.

The advantages of hydrostatic transmission over hydrodynamic transmission are: on the one hand, its large control range, which allows stepless or only a few gear changes in the additional gearbox. On the other hand, its design allows for integrated transmission solutions and allows installation in modern wheel loaders at an angle or transverse to the direction of travel. In a closed loop, torque can be transmitted in both directions. Therefore, during braking, a "support" can be generated for the drive machine, which can reduce braking power and brake wear, which will lead to a reduction in the operating costs of the wheel loader. The simultaneous operation of the working hydraulics during braking allows the return energy to be additionally transmitted to another hydraulic pump and actuator. The decisive advantage of hydrostatic transmission is that it has a wide range of open-loop and closed-loop control and can accept the available engine power at any speed. Therefore, in the current and future research and development, it has become an inevitable trend to optimize the design of the transmission device of the tire loader.

Comparison of the traction and speed provided by the torque converter and the hydrostatic device: When the available engine power is all used for driving transmission, the hydraulic traction is usually reduced by about 80% of the weight of the loader. This traction can not only meet the requirements, but also avoid the phenomenon of the drive wheel slipping when the loader cuts into the cargo. This is a typical working condition of wheel loaders and often occurs when the loader cuts into the cargo pile. Compared with the dynamic pressure transmission with a rapid increase in traction, the tire wear of the hydrostatic transmission is significantly reduced at this point. When the working hydraulics are operated at the same time, the hydrostatic transmission can provide the maximum traction. Especially when loading bulky cargo, the loader with hydrostatic transmission can improve work efficiency. In the hydrostatic transmission, due to the decrease in the speed of the drive motor, only about 50% of the original traction can be provided.

The torque carrying capacity of the torque converter is a quadratic equation of the speed. This means that the torque converter can only accept the full torque at a certain speed, generally at the load speed. At speeds below this, the acceptance capacity drops sharply, which leads to a drop in traction and speed. When using hydrostatic transmission, it can theoretically cover the entire engine characteristic curve family due to its free distribution of speed changes and torque changes. And in combination with various open-loop and closed-loop control, it can also optimize noise and energy consumption. In this way, as long as the drive motor speed is regulated at an optimal working point, the driver can make the required requirements for acceleration, traction or speed only by the position of the accelerator pedal.

The purpose of optimizing the transmission is to reduce the burden on the driver, on the one hand to improve their working conditions, and on the other hand to enable them to concentrate on the decisive work tasks. In addition to the performance advantages, modern hydrostatic transmission solutions coordinated with special drive power are also very competitive in price compared to torque converter transmission solutions.