目的通过对往复运动齿轮齿条传动过程中压力、膜厚、温度的计算,获得往复运动齿轮齿条的润滑状况,为机构的设计提供理论依据。方法将齿轮齿条的传动模型简化为圆柱与无限大平面之间的运动,建立往复运动齿轮齿条传动的热弹流润滑模型。采用Ree-Eyring流体,压力求解采用多重网格法,弹性变形采用多重网格积分法,计算得到齿轮齿条往复运动过程中的中心压力、中心膜厚、最小膜厚和最高温度,并与单向运动情况比较。结果与单向运动相比,往复运动由于在换向过程中存在加速、减速过程,降低了齿轮齿条机构在啮合周期内润滑油膜厚度,啮合线上变速过程始末附近区域膜厚和压力都会产生一定程度的波动。换向瞬时,受挤压效应的影响,产生油膜凹陷,油膜变薄,润滑状态变差。结论在计算往复运动齿轮齿条润滑油膜与压力时,存在换向的啮合周期需要着重讨论。在工程实际中设计往复运动齿轮齿条润滑时,应着重考虑单双齿啮合转换点与换向点处的润滑情况。
The work aims to obtain lubrication condition of the gear rack transmission in reciprocating motion by calculat- ing pressure, film thickness and temperature during the process of gear rack transmission in reciprocating motion, so as to pro- vide theoretical basis for design of gear rack mechanism. Transmission model of the gear rack was simplified to motion between cylinder and infinite plane, a thermal elastohydrodynamic lubrication model was established for gear rack transmission in reci- procating motion. Provided with Ree-Eyring fluid, the pressure was solved in multi-grid method, elastic deformation was solved in multiple-grid integration method, then central pressure, central film thickness, minimum film thickness and maximum tem- perature during reciprocating motion were calculated and finally compared with one-way movement. The lubricating oil film thickness of gear rack mechanism during meshing period was reduced due to acceleration and deceleration process in reversing process of reciprocating motion when compared with one-way movements compared with the one-way movement. Film thick- ness and pressure in area near the beginning and end of reversing process in meshing line would fluctuate to certain degree; oil film depression was produced under squeeze effect of instantaneous reversing, film thickness became thinner and lubrication state became worse. Meshing cycle subject to reversing shall be discussed emphatically to calculating the lubricating oil film thickness and pressure of reciprocating gear rack; in engineering practices, lubrication at single-double tooth meshing conver- sion point and reversal point shall be considered emphatically in designing reciprocating gear rack lubrication.