【作者】 张伟；

【导师】 饶绮麟； 张文明；

【作者基本信息】 北京科技大学 ， 车辆工程， 2015， 博士

【摘要】 发动机—发电机系统是电动轮矿用自卸车的动力来源,是整车正常运行的核心保证,该系统的旋转轴系是一个多自由度的振动系统,由于系统各部件并非绝对的刚体,而是存在弹性,因此在高速旋转过程中,轴系局部区域会产生幅值不等、相位不等的瞬时转速起伏,形成往复扭转振动。在发动机、发电机的不均匀扭矩激励作用下,当激励频率与系统的固有频率相等时,轴系的扭转振动将会发生严重的共振现象,产生巨大的共振载荷,导致断轴、齿轮打齿、零部件使用寿命缩短等后果,从而危及整车的正常行驶和零部件的使用寿命,系统的扭转振动问题一直是影响装置工作稳定性、可靠性和噪声控制的主要因素之一,也是科研人员设计工作的重点之一。车辆在实际运行过程中,发动机—发电机系统轴系在气体爆发压力、活塞连杆往复惯性力、电磁参数激励以及机电耦合作用激励等的联合作用下,产生复杂的扭转振动现象,为了全面研究发动机—发电机系统轴系扭转振动特性,有必要对系统进行全面分析研究。本文研究的目的就是根据系统轴系的结构特点,从多个角度,采用多种研究方法,分析研究发动机—发电机系统轴系在各种内部激励和外部激励共同作用下的扭转振动特性和振动规律,为此类系统的设计、优化以及减振降噪等提供理论依据。本论文以电动轮矿用自卸车发动机—发电机系统旋转轴系为研究对象,围绕其扭转振动问题进行相关研究：首先,针对系统轴系的扭转振动问题,在对发动机、发电机等单元的内部结构参数、外激激励等全面分析的基础之上,建立系统轴系扭转振动的集总质量模型,并获得系统扭转振动的动态微分方程,采用系统矩阵法即传统的计算广义Jacobi特征值的方法,对自由振动特性进行分析；针对强迫振动求解存在非线性项的问题,选取多尺度法对强迫振动特性进行求解,获取系统轴系扭转振动的共振频率和振型。其次,利用AMESim软件搭建发动机—发电机系统轴系一维扭转振动仿真模型,并分别对各单元进行全面的分析计算,分析轴系的自由振动和强迫振动,获取轴系的扭转振动频谱图和瀑布图,验证理论求解的正确性,同时探究系统部分零部件扭转刚度变化对系统轴系扭转振动特性的影响。第三,搭建系统轴系扭转振动试验台,以模拟实际车辆运行中轴系扭转振动特性为目的,根据结构特点采用非接触式扭转振动测试法,利用LMSSCADAS测试系统完成试验测试。针对实际车辆的工作特点,制定了试验台测试工况,包括怠速工况测量、定转速测量、转速追踪测量、变负载测量等。通过对角速度波动图、瀑布图、谐量阶次图、阶次追踪图等分析的基础上,获得轴系的固有频率、系统产生共振的临界转速、负载变化对扭转振动的影响规律等,验证理论分析和模型仿真的正确性与可靠性。第四、在前文分析的基础上,对扭转振动的控制措施进行研究,主要研究曲轴扭转减振器和双质量飞轮扭转减振器对系统扭转振动特性的影响,根据研究对象的特点设计减振器参数,分别采用不同的方法对两种控制措施的减振效果进行分析,分析结果可以作为今后设计参考。通过本文的理论分析、仿真模拟、试验验证及扭转振动控制措施研究,证明应用本文建立的电动轮矿用自卸车发动机—发电机系统轴系扭转振动模型,计算求解的轴系扭转振动特性与实际工况试验测试结果基本吻合,该试验台可以用于研究此类轴系的扭转振动特性,所采用的分析方法、获得的研究结果及提出的减振措施可以应用于实际车辆设计研究。更多还原

【Abstract】 Engine-generator system, the vital component for the electric drive mining dump truck, is the power supply. Its shafting is a multi-degree of freedom vibration system. Considering that the components are elasticity, not absolutely rigid, on high-speed rotation condition, portions of shafting will produce transient rev fluctuation with various magnitudes and phases, which is torsional vibration. Under the uneven torque excitation from the engine and the generator and the excitation frequency near the natural frequency of the system, the torsional vibration will bring resonance. The load from resonance will lead to disaster, such as broken shaft and gear teeth, shortened part life, even endangered the safety of the vehicle. Torsional vibration is one of the major factors for effecting reliability, stability and noise level. It is the focus field studied by researchers.On the working situation, engine-generator system suffers the combined effects of the gas explosion pressure, piston-rod inertia force, electromagnetic parameter and electromechanical coupling excitations. The complex torsional vibration is normal phenomenon. For comprehensively researching the shafting torsional vibration characteristics, it is necessary to analyze the engine-generator system. According to the structural of engine-generator shafting, this article focuses on analyzing the torsional vibration characteristic and routine effected by internal and external incentives with multiple aspects, complex methodologies. The theoretical reference is provided for systems design, optimization, vibration and noise control.In this paper, the research object is the engine-generator system rotating shafting. And torsional vibration is the entrance.First of all, for the shafting torsional vibration problem, the lumped mass model is established, after completely analyzed the structural parameters inside and incentives outside. Thus dynamics differential equation of torsional vibration is derived. The free vibration characteristics is calculated by using the traditional algorithm of the generalized Jacobi eigenvalues. For the nonlinear terms in forced vibrations, the multiple scales method is selected as the vibration characteristics solution to obtain the natural frequency and vibration mode.Secondly, the1D simulation model of the engine-generator system shafting torsional vibration is built with AMESim. Through respectively calculating each component, analyzing the free/forced vibration, shafting torsional vibration spectrum and waterfall figures are plotted to verify the theory solution. Meanwhile the correlation between the stiffness of the parts and vibration characteristics.Thirdly, the torsional vibration test bed is built to simulate shafting torsional vibration characteristics for reality. According to the structural characteristics of torsional vibration, the non-contact method is used with LMS SCADAS acquisition instrument to complete experimental verification. The test procedure is from actual working conditions, including constant speed, speed tracking, variable load measurement. With the analysis of the angular velocity fluctuations, waterfall, harmonic order, order tracking figures, etc., the natural frequency, resonance critical speed, impact of variable load are obtained.Fourthly, besides mentioned above, control method is studied. The major object are the effects of crankshaft torsional damper and dual-mass flywheel damper on the characteristics of shafting torsional vibration and special dumper design. Different methods are used to analyze damping effect of two dumpers which can be the reference for future designs.The theory, simulation, test and control method prove that the calculated characteristics using the model in this paper is coincide with the actual test. The test bed can be the development tool for a series of shafting torsional vibration characteristics research. The Research methods, conclusion and damping measures can be applied to the actual design.更多还原