A four-stage hydraulic-mechanical stepless transmission for tracked vehicles

Abstract

The invention discloses a four-stage type hydraulic machine stepless transmission device used for caterpillars. The four-stage type hydraulic machine stepless transmission device comprises a planet coupling mechanism, a hydraulic speed regulating component, a stage changing operation component, a hydraulic stepless steering component and a hydraulic deceleration component; and the planet couplingmechanism comprises four planetary lines, the hydraulic speed regulating component comprises a hydraulic speed regulating loop composed of a variable pump and a constant displacement motor, the stagechanging operation component comprises four clutches and one brake, the hydraulic stepless steering component comprises a hydraulic speed regulating loop composed of a variable pump and a constant displacement motor, and the hydraulic deceleration component comprises a hydrodynamic coupling. By means of the four-stage type hydraulic machine stepless transmission device, the manner that hydraulic machines are compounded with stepless transmission is adopted, four forward gears, one reverse gear, a center steering gear and an emergency meeting mechanical gear are achieved through the planet coupling mechanism, the hydrodynamic coupling can be used for achieving hydraulic deceleration under the vehicle high-speed working condition, the needs of vehicle high-speed overland and flexible steering can be met, and the vehicle dynamic property and economical efficiency are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of crawler vehicle transmission, and relates to a four-stage hydraulic mechanical stepless transmission device for crawler vehicles. Background technique [0002] The transmission system is the core system of vehicle power transmission, and its performance has a great impact on the power performance and fuel economy of the entire vehicle. Although the hydromechanical integrated transmission is widely used in tracked vehicles, its speed regulation characteristics in specific gears are determined by the speed regulation characteristics of the engine. The complex and changeable road surface leads to drastic changes in the engine load. The hydraulic-mechanical integrated transmission device needs to frequently use the hydraulic torque converter to enter the hydraulic working condition, which leads to the unsatisfactory transmission efficiency of the entire transmission system, and the fuel economy cannot be guar...

AI Technical Summary

Problems solved by technology

Although the hydromechanical integrated transmission device has a wide range of applications on tracked vehicles, its speed regulation characteristics in specific gears are determined by the speed regulation characteristics of the engine. The complex and changeable road surface leads to drastic changes in the engine load. The hydraulic-mechanical integrated transmission device needs to frequently use the hydraulic torque converter to enter the hydraulic working condition, which leads to the unsatisfactory transmission efficiency of the entire transmission system, and the fuel economy cannot be guaranteed

The existing hydraulic-mechanical integrated transmission device realizes the speed change through several gear ratios with stages, but it brings a great shifting impact when shifting gears, which greatly affects the life and reliability of the shifting control elements and the related mechanical structures of the whole machine. , the life of the hydromechanical integrated transmission is often limited by the life of the friction plate

Although the hydrostatic stepless transmission can conveniently realize the stepless speed regulation, so that the engine can always work in the economic speed range, the efficiency of the closed speed regulation circuit of the hydraulic pump motor used in the hydrostatic transmission is also low, which cannot meet the requirements of a wide range of tracked vehicles. The demand for variable speed and torque

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