材料期刊网

目的 通过对传动过程中压力和膜厚的计算,提高齿轮齿条机构润滑性能,降低齿轮齿条传动过程中的磨损.方法 简化齿轮齿条传动过程载荷图谱,运用简化的实际载荷曲线,建立齿轮齿条啮合过程的弹流润滑计算模型,对齿轮齿条啮合过程中的瞬态弹流润滑问题进行研究.考虑啮合过程中单、双齿啮合时不同的载荷,计算一个啮合周期沿啮合线上的中心压力、中心膜厚、最大压力、最小膜厚以及啮入点、节点、啮出点压力和膜厚,还有双齿啮合区转换为单齿啮合区、单齿啮合区转换为双齿啮合区前后瞬时的压力和膜厚.压力求解采用多重网格法,弹性变形采用多重网格积分法,得到了齿轮齿条传动机构的瞬态弹流润滑完全数值解.结果 载荷突然升高引起中心压力突然升高,中心膜厚最大值出现在双齿啮合区与单齿啮合的临界点.啮合线上最小膜厚和最大压力出现了波动.计算得出啮入瞬时膜厚最薄,润滑状况较差.结论 沿啮合线各瞬时压力与膜厚不断变化,载荷突变引起的压力突变应通过提高轮齿强度等方式防止表面疲劳破坏的产生.整个啮合过程中,啮入点为危险点.

The work aims to improve lubrication performance of gear rack mechanism and reduce wear during transmission process of gear rack by calculating pressure and film thickness during transmission process. Load map of gear rack transmission process was simplified, a simplified actual load curve was used, and a calculation model of elastohydrodynamic lubrication was built for gear-rack meshing process, so as to study transient elastohydrodynamic lubrication during gear-rack meshing process. Different load between single and double teeth during meshing process was considered to calculate central pressure, central film thickness, maximum pressure and minimum film thickness along meshing line in a meshing cycle, pressure and film thickness at the engaging-in point, node, engaging-out point, transient pressure and film thickness when double teeth meshing zone con-verted to a single tooth meshing zone, and single tooth meshing zone converted to a double teeth meshing zone. Multi-grid me-thod was applied to calculate the pressure, multi-grid integration method was applied to calculate elastic deformation, complete numerical solutions were obtained for the transient elastohydrodynamic lubrication of gear-rack transmission mechanism. Sud-den increase in central pressure was caused by sudden increase in the load, the maximum values of the central film thickness were present at the critical point between the double teeth meshing zone and the single tooth meshing. The minimum film thickness and maximum pressure fluctuated on the meshing line; transient film thickness was the thinnest and lubrication condi-tion was poor during engaging-in. The pressure and film thickness along the meshing line change constantly; sudden change in pressure caused by that in load by improving strength of gear teeth to prevent occurrence of surface fatigue damage. Throughout the meshing process, the engaging-in point is a dangerous point.