全液压推土机液压与控制系统研究

【作者】 易小刚；

【导师】 龙水根；

【作者基本信息】 长安大学 ， 机械设计及理论， 2005， 博士

【摘要】 该论文研究依托于三一重工与长安大学合作课题:“全液压推土机匹配与行驶控制系统研究”,历时两年多,在样机的改进前后做过数次牵引实验、载荷实验、工业实验以及液压系统台架实验,最终使得新生产的样机性能取得了比较满意的结果。 论文研究主要完成以下内容: 1.对推土机的国内外研究现状、相关专利和发展趋势进行了分析与综合,对比分析了电控、液控和电液复合控制的控制方式,给出了全液压推土机的控制方案。并在工业生产中得到了应用。 2.通过对全液压推土机典型工况的分析,在理论上研究了在典型工况下的控制算法(空行驶工况、倒退工况、铲掘工况和搬运工况等)。 3.对全液压推土机的关键技术参数进行了研究,确定全液压推土机的额定滑转率应该为12～15%;牵引比均值为1.48,比功率均值为7.2(kW/T),实际应用取值要等于或稍大于该均值。 4.参照长安大学焦生杰博士在《沥青混凝土摊铺机液压驱动行驶与控制系统研究》论文中关于速度刚度的概念,对车辆驱动液压马达速度刚度进行了理论与实验研究,研究结果表明选择大排量马达对于改善推土机载荷适应能力有明显效果,且发现在马达排量比小于0.4的时速度刚度值很小,大于0.7的时侯速度刚度值达到最大且变化趋于平稳,此时系统抗负载变化的能力较强。 5.对泵、马达的效率以及全液压推土机的牵引性能进行了理论与实验研究,提出了在传统牵引性能曲线中增加效率曲线,对全液压推土机样机进行合理的评价。 6.通过行走液压驱动系统的压力载荷波动分析,研究了全液压推土机行走液压系统的可靠性,并提出了延长液压系统工作寿命的措施。 7.根据液压系统设计和分析的需要,在VB的平台上开发了全液压推土机驱动系统计算机辅助设计软件。可以进行关键技术参数的重复试算和曲线分析,可满足工业设计的实用要求。 8.通过初期样机与改型后样机的牵引性能实验、载荷性能实验、实际工业性实验和可靠性实验,证明了按新的匹配指标体系完成的样机的作业性能、牵引性能和生产率等远高于初期样机的性能。更多还原

【Abstract】 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.更多还原