【作者】 吴飞；

【导师】 江征风；

【作者基本信息】 武汉理工大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 汽车动力传动轴系结构复杂,其动力来源于汽车发动机,而汽车发动是一个固有的扭振激振源,使得传动轴系成为了多自由度振动系统,扭振是振动和噪声的主要来源,直接影响着现代乘用车的品质。双质量飞轮介于发动机与传动轴系之间,它不但具有传统飞轮的功能,还可通过变化质量和刚度来调整传动轴系的扭振固有特性,并利用自身的阻尼结构降低轴系的振幅。可以有效地吸收和衰减发动机输出振动,提高传动轴系运转的平顺性,它已成为目前改善汽车动力传动系统扭振特性最有效的手段之一。因此深入研究汽车双质量飞轮动力传动轴系扭振特性,为提高双质量飞轮在汽车动力传动系统中的扭振减振性能提供理论及技术上的支持具有十分重要的理论价值及实际意义。本文主要工作与创新如下：1、建立了分档位的双质量飞轮轴系扭振计算模型。运用扭振系统当量建模的理论,结合双质量飞轮动力传动轴系结构特点,采用有限元分析等方法,对发动机、变速箱、传动轴、驱动桥等部件及整车质量的转动惯量、扭转刚度进行等效当量转化,着重对调速系统进行了分析,建立了汽车动力传动系统不同档位下的扭振动力学计算模型。2、分析了双质量飞轮轴系自由扭振特性。以VM25C乘用车柴油机匹配LUK1005双质量飞轮扭振减振器的轴系为研究对象,采用系统矩阵法对其自由扭振进行分析和计算,得到了固有频率与振型。3、对双质量飞轮轴系强迫扭振特性进行了分析。以双质量飞轮扭振减振器轴系为研究对象,通过分析汽车传动轴系激振的来源,确定了发动机内气体压力变化所产生的激振力矩及其运动部件转动惯量所产生的激振力矩,对发动机激振源进行了简谐分析,进而对在发动机激振下的轴系强迫扭振进行了计算分析,得到了轴系的扭振幅值。4、开发了汽车传动轴系扭振特性分析软件,实现了轴系扭振固有频率计算、振型显示、临界转速计算等功能。5、研发并搭建了双质量飞轮轴系扭振试验台。试验台以VM发动机为激振源,以模拟实际轴系扭振特性为目的。为了使该试验台能够模拟多种车型的传动轴系的动力学特性,通过分析惯量轮盘组的质量转换、临界转速及运动平衡问题,设计出惯量轮盘组模拟惯量系统。在修正了试验台轴系的刚度后确定了试验台的结构。并通过对传动轴扭振节点的理论分析,得到了各阶次下扭振信号的测量位置。6、对双质量飞轮轴系扭振特性进行了试验验证。进行了怠速时轴系扭振的试验,各工况下轴系扭振的比较试验及扭振试验台测试误差分析。试验表明,该试验台能够模拟多种车重1500KG-2000KG的车型在不同负载情况下不同挡位、不同转速的轴系扭振特性。更多还原

【Abstract】 The structure of automobile power transmission shaft system is very complex, and its power comes from automobile engines which is a source of torsional vibration. The drive shaft is a multi-degree of freedom vibration system and torsional vibration is a main source of vibration and noise, which becomes a direct impact on the quality of modern passenger cars. Dual-mass flywheel is between engine and driving shaft system, so it not only has traditional function of the flywheel, but also can adjust natural characteristics of torsional vibration by changing the mass and rigidity of the Department. Its own damping structure can also reduce the amplitude, so dual-mass flywheel can effectively absorb and attenuation engine vibration and enhance the smoothness of operating shaft system. It has become one of the most effective methods for improving vehicle powertrain torsional vibration characteristics. Further study of automotive power transmission shaft torsional vibration characteristics with dual-mass flywheel can provide theoretical and technical support to improving torsional vibration damping properties of automotive powertrain with dual-mass flywheel. It has great theoretical value and practical significance.The following tasks and innovations have been completed:1. Torsional vibration model of dual-mass flywheel under different stalls has been established. Based on equivalent torsional vibration system theory and combined with structure features of power system with dual-mass flywheel, the finite element analysis method is used for being equivalent conversion to the moment of inertia and torsional stiffness of parts and whole vehicle quality, such as the engine, gearbox, drive shaft, drive bridges, and emphatically for analysing speed control system. The mechanical computing model of automotive driveline torsional vibrations under different stalls is established.2. The free torsional vibration characteristics of dual-mass flywheel shaft are analyzed. The researched object is the shaft of VM25C Diesel passenger vehicles matching LUK1005dual-mass flywheel torsional vibration damper. The free torsional vibration has been analysed and calculated by adopting system matrix method, then natural frequencies and vibration modes have been obtained.3. Forced torsional vibration characteristics of dual-mass flywheel shaft is analyzed. The researched object is the shaft of dual-mass flywheel torsional vibration damper. By analyzing the excitation source of automotive transmission system it is determined that the exciting moment of force generated by gas pressure changes inside the engine and moment of inertia changes of its motion part, and then the shaft torsional vibration under excitation force of the engine is calculated and analysed. The torsional amplitude has been calculated.4. The analysis software for torsional vibration characteristics of automobile transmission shaft system has been developed. It has many functions such as calculation of shaft’s natural frequency, and display of vibration mode, calculation of critical speed, etc.5. The test-bed of the shaft with dual-mass flywheel torsional vibration is designed and built. Excitation source is the VM engine, and its power is 105KW in order to simulate the shaft actual torsional vibration characteristics. In order to make the test-bed capable of simulating a variety of models’dynamics characteristic of drive shaft system, inertia wheel group has been designed by analyzing the mass conversion of inertia wheel group, critical speed and dynamic balance. The structure of test-bed has been fixed on after the shaft stiffness of test-bed being modified. The order times value of torsional vibration signal has been obtained through theoretical analysis to torsional vibration node of drive shaft.6. The dual-mass flywheel torsional vibration characteristics is verified by experiment. The experiments include the torsional vibration test under the idling condition and the comparative test of torsional vibration under various operating conditions. Then the test error analysis of torsional vibration test is analyzed. Tests show that the test-bed can simulate various shaft torsional vibration characteristics for vehicle weight 1500KG-2000KG under different conditions that includes different shifts and different speed. The simulation of actual working conditions is realistic, the extraction of measuring torsional vibration signal is stable.更多还原