Dynamic Characteristic Analysis and Clutch Engagement Test of HMCVT in the High‐Power Tractor

Abstract

Hydromechanical continuously variable transmission (HMCVT) is capable of bearing large torque and has wide transmission range, which is suitable for high-power tractors. Dynamic characteristics could influence the tractor life, especially in a high-power tractor. Wet clutch is the crucial component in the HMCVT, which could smooth and soft power transmission. Therefore, it is important to study the dynamic characteristics and implement the wet clutch test of HMCVT. In this paper, AMESim is used to establish virtual models of gearbox, pump-controlled hydraulic motor system, and shifting hydraulic system. Then, a simulation study of tractor operation under working condition is carried out. The internal and external meshing forces of the planetary row are analyzed. Finally, the wet clutch engagement process of HMCVT in the high-power tractor is tested to verify the oil pressure. The simulation results show that the values of internal and external meshing force become larger as the throttle opening increases. At the moment of shifting change, the meshing forces of the planetary gear have great impact. The clutch test shows that the trend of the oil filling curve obtained from the bench test is similar to that obtained from the theoretical curve, which verifies the simulation results.

Research on HMCVT Parameter Design Optimization Based on the Service Characteristics of Agricultural Machinery in the Whole Life Cycle

“…η ig (12) in which η HM 2 and η HM 4 are the gross efficiencies of stage HM 2 and stage HM 4 of 5-stage HMCVT when displacement ratio ε < 0;…”

“…The HMCVT (Hydro-Mechanical Continuously Variable Transmission) can realize continuously variable speeds in a large range and also inherits the advantages of mechanical transmission's high efficiency and hydraulic transmission's high power [7][8][9][10] while overcoming the disadvantages, and thus, can meet the requirements of agricultural machinery like tractors better. Therefore, the HMCVT is applied widely to agricultural and engineering machinery, such as tractors, and the research on HMCVT has great significance [11][12][13][14].…”

Design of tractor virtual test system based on high-level architecture technology

“…It is essential in the development of tractor products as it allows for the assessment of their performance and guides the optimization of tractor design [ 1 ]. However, traditional tractor test technology poses challenges such as high costs, energy consumption, and demanding test equipment requirements, resulting in low efficiency in tractor product development [ 2 , 3 ]. To address these issues, the application of computer technology and virtual test technology in new tractor product development has emerged as an advanced approach.…”

Optimization of Shifting Quality for Hydrostatic Power-Split Transmission with Single Standard Planetary Gear Set

“…In this research field, Bao et al [16] constructed a clutch control system based on solenoid directional valves and optimized the clutch pressure, the flow, and the displacement ratio of the pump to the motor to improve the shifting quality of the power-split CVT. Chen et al [17] proposed a simulation model of a similar hydraulic control system, making it possible to further study the shifting dynamics of CVT tractors through computer simulation. Iqbal et al [18] conducted similar work.…”