基于热弹流润滑的金属带式CVT滑摩传动润滑油膜特性分析

发布时间：2019-01-23 08:00

【摘要】：金属片与带轮之间的润滑油膜同时承载着动力传递与润滑的任务,是金属带式CVT(Continuously Variable Transmission)动力传递链中最为关键的环节。油膜特性直接决定变速器的润滑效果和传动效率,但在实际工况下油膜参数无法直接测量,难以对其进行精确控制。针对此问题,本文基于热弹流润滑理论构建了求解润滑油膜特性参数的数学模型,采用数值模拟方法,分析了金属带滑移率、传递转矩、传动速比等工作参数对油膜特性的影响规律,为金属带式CVT的设计及发展基于油膜特性参数的控制方法提供参考。论文主要进行了以下工作:(1)对无级变速机构及其动力传递过程进行了理论性分析。研究了传动过程中金属带各类滑动摩擦形成的机理,分析了金属带滑移对变速器传动效率的影响。对滑移状态下金属带与带轮之间润滑油膜形成机理进行了分析,发现润滑油膜处于弹流润滑状态,且温度对油膜有较大影响。(2)基于热弹流润滑的相关理论,建立了适合本研究的油膜数学模型。根据变速机构结构参数推导了传递转矩、速比、滑移率与模型中相对速度、载荷及综合曲率半径之间的关系,并根据实际工况确定了方程的边界条件。分析了模型中各方程的特点,确定了求解流程,并进行了求解。(3)通过数值模拟得到了油膜压力、油膜厚度及油膜温度的分布情况。借助数值仿真研究了各工作参数对油膜对称面上压力、温升、膜厚影响规律。设计了考虑交互作用的正交试验,得到了最大压力、最小膜厚、最大温升对各工作参数的敏感度。(4)设计了油膜温度试验,获取了油膜在各工作参数不同水平下的温度。试验结果显示试验所测温度值与仿真值之间存在一定差值,最大可达12℃,但是变化趋势基本一致,仿真结果经过修正后可以作为金属带式CVT的设计及发展基于油膜特性参数控制方法的参考依据。
[Abstract]:The lubricating oil film between the metal sheet and the belt wheel carries the task of power transfer and lubrication simultaneously, which is the most important link in the metal belt CVT (Continuously Variable Transmission) power transfer chain. The oil film characteristics directly determine the lubricating effect and transmission efficiency of the transmission, but the oil film parameters can not be measured directly under the actual working conditions, so it is difficult to control them accurately. In order to solve this problem, a mathematical model for solving the characteristic parameters of lubricating oil film is constructed based on the theory of thermo-elastohydrodynamic lubrication. The slip ratio and transfer torque of metal belt are analyzed by numerical simulation method. The influence of working parameters such as transmission speed ratio on oil film characteristics provides a reference for the design of metal belt type CVT and the development of control method based on oil film characteristic parameters. The main work of this paper is as follows: (1) theoretical analysis of continuously variable speed mechanism and its dynamic transfer process is carried out. The forming mechanism of sliding friction of metal belt in transmission process is studied, and the influence of metal belt slip on transmission efficiency is analyzed. The formation mechanism of lubricating oil film between metal strip and belt wheel is analyzed. It is found that lubricant film is in elastohydrodynamic state and temperature has great influence on oil film. (2) based on the theory of thermo-elastohydrodynamic lubrication, A mathematical model of oil film suitable for this study was established. According to the structural parameters of the variable speed mechanism, the relations between the transfer torque, speed ratio, slip ratio and relative velocity, load and comprehensive curvature radius in the model are derived, and the boundary conditions of the equation are determined according to the actual working conditions. The characteristics of each equation in the model are analyzed, and the solution flow is determined. (3) the distribution of oil film pressure, film thickness and oil film temperature is obtained by numerical simulation. The effects of working parameters on the pressure, temperature rise and film thickness on the symmetrical surface of oil film were studied by numerical simulation. The orthogonal test considering the interaction is designed, and the sensitivity of the maximum pressure, the minimum film thickness and the maximum temperature rise to the working parameters is obtained. (4) the oil film temperature test is designed, and the oil film temperature at different working parameters is obtained. The experimental results show that there is a certain difference between the measured temperature value and the simulation value, and the maximum value can reach 12 鈩，

本文编号：2413615