Full Hydraulic Studies, Hydraulic And Control System

The dissertation research relies on the project, the study of the matching and controlling system of the full hydraulic bulldozers, cooperated by SANY Heavy Industries and Chang'an University. After more than two years of research, the newly remodeled sample machine has got satisfied performance finally through traction experiment, loading experiment, industrial experiment and platform experiment around the period of remodeling.The following conclusion can be got from the dissertation study.1. The history, current situation and the developing trend of the machine within and out of the country are analyzed and synthesized. The control scheme of the full hydraulic bull dozers, which has been put into practice in industries, has been put forward followed the contrast of electronic control, hydraulic control and electronic-hydraulic control.2. Through the analysis of the typical working condition, the theoretic control arithmetic has been brought forward used in different occasions, including unloaded traveling, forwarding, reversing, shoveling and conveying.3. From the study of the key technical parameters of the machine, the rated slip ratio should be set 12 to 15 percent. When in real application, the force-to-weight ratio should be a little more than the mean 1.48 and the power-to-ratio should be slightly more than the mean 7.2 (kW/T).4. According to the idea of the velocity stiffness studied in the Dr Jiao Sheng-jie's dissertation, study on the hydraulic drive travel and control system of the asphalt concrete pavers, the velocity stiffness of vehicle's hydraulic drive motor are researched in theory and experiment. The result of the research work shows that higher displacement motor can improve machine's ability to suit the load and the stiffness value is too little when the displacement of the motor is less than 0.4, and goes to stable when the displacement is more than 0.7.5. Combined the academic and experimental study of efficiency of the bumps and the motors and the traction capability of the machine, the performance of the whole machine can be evaluated effectively by the way of adding efficiency curves on the traditional traction capability curves.6. Though the analysis of the pressure vibration of hydraulic drive system caused by load, the reliability of the hydraulic system has been studied and themeasures has been promoted to extend the life of the hydraulic elements.7. By the request of the design and analysis of the hydraulic, based on the VB, the Computer-Aided-Software of the drive system of the full hydraulic bulldozers has been developed. The software is of much practice for the function of re-calculation and curve analysis.8. The traction experiment, loading experiment, practical industrial experiment and reliability experiment prove that the working performance, traction performance and productivity of the new sample machine which is designed in remodeled matching index system is obviously better than the original sample machine.