摘要
变速器是汽车传动系的重要组成部分,其运动学和动力学特性关系到变速
器本身乃至整车性能的发挥。虚拟样机技术在系统动力学仿真中的成功应用不
仅可以提高仿真精度,而且可以缩短产品设计周期,对于工程实际具有重要的
应用价值。
本文以一台变速器为研究对象,从多方面开展了基于虚拟样机技术的变速
器动力学仿真研究。探讨了变速器中齿轮-转子-轴承系统的刚体和柔性体的
动力学仿真的研究方法,对同步器工作过程的仿真方法做了深入的研究,仿真
结果更接近变速器的实际工况,对工程实际具有一定的指导作用。本文主要内
容如下:
首先在变速器零件 UNIGRAPHICS(简称 UG)三维模型的基础上进行装配建模,
利用装配主模型在 UG 中创建运动分析方案进行变速器运动学仿真研究。在运动
仿真过程中,进行干涉检查,从而验证了变速器几何参数设计的合理性。
同步器是汽车变速器的重要部件,本文推导出同步器摩擦锥面平均半径的计
算公式,针对同步器的工作过程分别进行了理论计算和基于多体动力学分析软件
MSC-ADAMS 平台的仿真分析,并对理论计算结果和计算机仿真结果进行了对比分
析。
在 MSC-ADAMS 中建立了变速器传动机构的多刚体动力学仿真模型,基于
Hertz 静力弹性接触理论推导出直齿轮及斜齿轮的接触力仿真参数计算公式。仿
真得到的传动齿轮的啮合力的大小及频率都和理论计算结果一致,从而验证了计
算公式的正确性。
分别用模态试验和有限元技术对变速器的二轴进行了动态特性研究,研究结
果验证了有限元模型的准确性。利用此有限元模型,在 ANSYS 中生成二轴的模态
中性文件,建立了变速器传动机构的柔性体动力学仿真模型。仿真得到的轴承处
所受的动载荷,为轴及轴承的强度、刚度及寿命分析提供了数值依据。
Since transmission is an important component of vehicle’s power train, the
character in kinematics and dynamics of transmission is related to the reliability of
vehicle directly. The application of virtual prototyping technology not only improves
simulation technique’s precision, but also saves the time.
Taking example for a transmission used in vehicle, the key steps and approaches
of dynamic simulation on the transmission based on virtual prototyping technology
are discussed. This thesis makes a deep research on the dynamics simulation methods
of the gear-rotor-bearing system and the synchronizer mechanism. The simulation
results are more precise, and this method is very useful for the practical design. The
main points of the thesis are listed below.
Firstly, assembly model of the transmission is built in the UNIGRAPHICS
environment. Based on the assembly model, UG Scenario is put up for kinematically
analyzed, simulated and animated. Interference check in the motion process indicates
the transmission’s geometry parameters are reasonable.
Synchronizer is an important device of transmission. In the thesis, average radius
of friction cone in synchronizer is presented. Some important parameters in the
synchronizing process are calculated, and then the process is simulated in the
MSC-ADAMS environment, furthermore, the two results used different method is
compared and analyzed.
Some parameters used in simulation of exciting force in both spur gears and
helical gears are presented based on Hertz formula. Then, the multi-body dynamics
simulation model of the gear train mechanism is established in the thesis. The
consistency of the simulation result and the calculated result indicates that the
magnitude and frequency of the exciting force in gears is correct.
The structural dynamics characteristics of the output shaft are analyzed through
both the model test and the Finite Element Analysis. The consistency of the natural
frequencies and modal shapes verifies the veracity of the FE model. Based on the FE
model of the output shaft, the multi-body dynamics simulation model of the flexible
system is established in the thesis. Through the dynamics analysis of the flexible
system, the bearing impact is acquired, which is the basis of the further analysis of the
stress and stiff analysis on shafts and bearings.
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