重心偏置下齿轨车辆系统的动态行为

Dynamic Behavior of Rack Vehicle System Under Offset of Gravity Center

针对大坡度下车辆动态特性受齿轨车辆重心偏置影响的问题,在解析齿轮齿轨啮合激扰产生机理的基础上,考虑齿轮齿轨啮合冲击与轮轨动态接触行为的扰动效应,建立齿轨系统车轨耦合动力学模型,并经过现场实验验证了模型的有效性;采用所建立的模型,探究平直段以及坡道段车体重心横纵偏置对驱动齿轮动态接触行为以及齿轨车辆运行安全平稳性的影响。结果表明:齿轨车辆存在重心偏置时,齿轮齿轨啮合激扰对车辆运行特性有显著影响;车体重心横向偏置对轮轨垂向力与轮重减载率呈线性影响,当重心横向偏置达到0.3 m时,轮轨垂向力达到75 kN,轮重减载率达到0.44;轮轨作用力除受车体重心偏置作用产生增减载外,亦受齿轮齿轨动态啮合影响产生剧烈振动;轮重减载率、车体垂向加速度与车体平稳性对车体重心纵向偏置较敏感,当车体重心后置0.2 m时,平直段的车体垂向加速度增大1.8倍,坡道段增大3.7倍,车体重心后置1 m时,车体平稳性达到最优。研究结论可为我国山地齿轨铁路设计及安全运维提供理论支撑。

Addressing the problem that the rack vehicle dynamic characteristics are affected by the gravity center offset of the rack vehicle on a large slope,based on the analysis of the mechanism of gear-rack meshing disturbance,considering the disturbance effect of gear rack meshing impact and wheel/rail dynamic contact behavior,and the effectiveness of the model was verified by field experiments in this paper.Adopting the established model,the impact of the horizontal and vertical offsets of the vehicle gravity center on the dynamic contact behavior of the drive gear and the safety and stability of the rack vehicle in the straight section and the ramp section was explored.Results show that when the rack vehicle has a gravity center offset,the gear rack meshing disturbance has a significant impact on the vehicle running characteristics.The wheel-rail force is not only increased or decreased due to the offset of the vehicle gravity center,but also affected by the dynamic meshing of the gears and racks to produce severe vibrations.The lateral offset of the vehicle gravity center has a linear effect on the wheel-rail vertical force and the wheel load reduction rate.When the lateral offset of gravity center reaches 0.3 m,the wheel-rail vertical force reaches 75 kN,and the wheel load reduction rate reaches 0.44.The vertical acceleration of the car body and the stability of the car body are more sensitive to the longitudinal offset of the gravity center of the car.When the center of gravity is set to 2.0 m behind,the vertical acceleration is increased by 1.8 times,and the ramp section is increased by 3.7 times.When the center of gravity is 1 m behind,the stability of the car body is optimal.The conclusions of this study provide theoretical support for the design and safe operation and maintenance of mountain cog railways in China.