摘要
传统油膜压力特性研究大多忽略油膜的可压缩性以及轴颈惯性力对油膜压力的影响,但在高频动载荷或瞬态冲击载荷作用下,油膜压力随时间变化剧烈,而油膜密度、粘度等状态参数又是关于压力的函数,油膜不可压缩性假设不再适用。另外,轴颈本身具有很高的加速度,因轴颈高速运动而产生的惯性力也不能被忽略。因此,同时将可压缩性以及轴颈惯性力引入到油膜压力的数值计算,可使计算结果更符合实际物理现象。建立考虑轴颈惯性力的力平衡方程以及考虑油膜可压缩性的雷诺方程,计算轴承在瞬态冲击载荷如矩形脉冲、三角形脉冲以及正弦周期性载荷作用下的油膜压力特性,分析数值计算结果,研究外载荷幅值、脉宽以及相对间隙对油膜压力特性的影响,研究发现,相对间隙越大,轴颈惯性作用越不能被忽略;油膜压力衰减速度并不随外载荷幅值单调变化,外载荷幅值极小或外载荷幅值极大,量纲一油膜压力衰减速度均较快;脉宽变化对量纲一油膜压力衰减速度影响不大。在考虑可压缩性以及轴颈惯性力情况下,油膜压力时历曲线上会出现拍振现象。
The compressibility of the oil film and the influence of the bearing inertia force on oil film pressure are usually neglected in the traditional research of the pressure behavior of the oil film. But,oil film pressure changes greatly along with time when subjected to transient shock,which leads to unworthiness of the incompressibility assumption,considering the density and the viscosity of oil film changing greatly along with the oil film pressure. Besides,the velocity of bearing location is very high. And the inertia force due to the high velocity of bearing location can’t be overlooked. By introducing the compressibility and the bearing inertia force into the numerical calculation of oil film pressure,the calculation results will be more tally with the actual physical phenomenon. So the equilibrium equation considering the bearing inertia force and the Reynolds equation considering the compressibility of oil film are established. And the pressure behavior of the oil film is studied to get the influence of the load amplitude,pulse width and relative gap on the oil film pressure when subjected to transient shock loads,such as the rectangular pulse,triangular pulse and sine pulse. And it is shown that the decay rate of the oil film pressure has no monotonic relation with the load amplitude. The decay rate is high either the load amplitude is very big or very small;The pulse width has little influence on the decay rate of the oil film pressure;The bigger the size of the gap is,the bigger the influence of the bearing inertia force on the pressure of the oil film will be. In addition,the beat vibration can be seen on the pressure-time curve when the compressibility and the bearing inertia force are considered.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第17期93-99,共7页
Journal of Mechanical Engineering
关键词
可压缩性
惯性力
油膜压力
瞬态冲击载荷
Compressibility Inertial force Oil film pressure Transient shock load
