金属带无级变速器行星换向机构非线性动力学分析

发布时间：2018-01-19 02:27

本文关键词： 金属带无级变速器行星换向机构离合器控制齿轮非线性动力学　出处：《湖南大学》2012年硕士论文　论文类型：学位论文

【摘要】：行星齿轮传动系统具有结构紧凑、传动效率高等优点，被广泛应用于汽车、航空、船舶、风力发电等各个领域。但因系统内部存在复杂的振动问题，造成过大的噪声及动载荷，严重危害传动系统本身的可靠性。研究指出，行星齿轮传动系统是典型的自激振动系统，内部激励主要有时变啮合刚度、综合啮合误差、啮入啮出冲击等。另外，由于齿侧间隙引起齿轮脱啮及冲击载荷等问题，行星齿轮传动系统具有强非线性，以及复杂的非线性动力学表现，如分岔、混沌等。故围绕振动特性分析的行星齿轮传动系统非线性动力学问题一直是业内的研究焦点。在金属带无级变速器（CVT）传动系统中，行星换向机构是关键零部件之一。通过多片湿式离合器的控制，该机构可实现汽车的倒挡起步及行驶。在起步过程中，行星换向机构所传递的扭矩、转速均处于动态变化的过程，即非稳态，因此，行星换向机构在克服内部激励的同时，也承受着外部激励的袭扰。再者，外部激励中的转速同样会影响内部激励中的时变啮合刚度、综合啮合误差等因素，即内、外激励处于耦合作用状态，并非简单地线性叠加，这将导致行星齿轮系统故障分析的难度。鉴于在CVT国产化中，行星换向机构在倒挡疲劳试验期间经常出现振动、噪声、断齿等故障，严重削弱了CVT产品的寿命及可靠性。本文以齿轮系统动力学为理论基础，综合考虑时变啮合刚度、综合啮合误差、齿侧间隙等因素，建立了行星换向机构的非线性耦合运动微分方程。采用变步长4-5阶Runge-Kutta算法对其进行数值求解。根据仿真结果绘制了系统分岔图，并结合典型工况下的动载荷图、相图、庞加莱截面图和FFT频谱图，在频域和时域范围内系统地分析了系统运动状态随内、外激励参数的演变历程。针对行星换向机构可能出现的混沌状态，引入混沌时间序列分析理论计算最大Lyapunov指数，对系统是否处于混沌状态进行判定。最后，以齿侧间隙为切入点，对行星换向机构进行性能改进试验，以验证理论分析结果。试验表明，，齿侧间隙过大时，行星换向机构噪声大、断齿故障频发，减少齿侧间隙可有效降低系统振动，但保留合理的齿侧间隙可实现行星架浮动均载，防止因不均载导致断齿问题。
[Abstract]:Planetary gear transmission system has the advantages of compact structure, high transmission efficiency and so on. It is widely used in automobile, aviation, ship, wind power generation and other fields, but there are complex vibration problems in the system. It is pointed out that the planetary gear transmission system is a typical self-excited vibration system, and the internal excitation is mainly time-varying meshing stiffness. In addition, the planetary gear transmission system has strong nonlinearity and complex nonlinear dynamic performance due to the problems of gear degnamping and impact load caused by tooth side clearance. Such as bifurcation, chaos and so on. Therefore, the nonlinear dynamics of planetary gear transmission system around vibration characteristics analysis has been the focus of the industry. In the CVT transmission system, the planetary reversing mechanism is one of the key parts. In the starting process, the torque and speed transmitted by the planetary commutator are in the process of dynamic change, that is, non-steady state, so. The planetary reversing mechanism not only overcomes the internal excitation, but also bears the perturbing of the external excitation. Furthermore, the rotational speed in the external excitation will also affect the time-varying meshing stiffness and the comprehensive meshing error in the internal excitation. That is, the internal and external excitations are in the state of coupling, which is not simply linear superposition, which will lead to the difficulty of fault analysis of planetary gear system. In view of the localization of CVT, the planetary commutator often appears vibration, noise, broken teeth and other faults during the reverse gear fatigue test. The life and reliability of CVT products are seriously weakened. Based on the theory of gear system dynamics, the factors such as time-varying meshing stiffness, combined meshing error, tooth side clearance and so on are considered in this paper. The nonlinear coupled differential equations of motion of the planetary commutator mechanism are established and solved numerically by using the variable step size 4-5 order Runge-Kutta algorithm. The bifurcation diagram of the system is drawn according to the simulation results. Combined with the dynamic load diagram, phase diagram, Poincare section and FFT spectrum, the motion state of the system is systematically analyzed in frequency domain and time domain. According to the possible chaotic state of planetary commutative mechanism, the chaotic time series analysis theory is introduced to calculate the maximum Lyapunov exponent. Whether the system is in a chaotic state is determined. Finally, with the tooth side clearance as the breakthrough point, the performance improvement test of the planetary commutator mechanism is carried out to verify the theoretical analysis results. The test shows that when the tooth side gap is too large, the planetary commutator mechanism has a large noise and frequent broken teeth faults. Reducing the tooth side clearance can effectively reduce the vibration of the system, but keeping the reasonable tooth side clearance can realize the floating uniform load of the planetary frame and prevent the tooth breakage caused by the uneven load.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH132.46

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