Reciprocating spur gear rack is prone to lubrication failure near the reversing dead center position. Ree-Eyring lubrication fluid, multigrid method and multigrid integral method were used to calculate the pressure profile, film thickness and oil temperature rise. Compared with linear motion, the process of reciprocating commutative movement is more complicated and the lubrication state are more unstable. The effects of different reversing duration time and commutation meshing state on lubricant film were analysed. The results show that, the oil thickness during the gear reversing process is significantly reduced. While shortening the reversing time can improve the lubricating film thickness, it causes the instantaneous oil temperature to rise. Therefore, the gear tooth damage caused by high temperature can be avoided by prolonging the reversing duration time properly. The longer the reversing duration time, the minimum value of central film thickness and central pressure is closer to the meshing outlet area. No matter what the reversing time change, the minimum lubrication film thickness is in the reversing dead center position. So the reversing dead center is still the dangerous point for the lubrication failure of the spur gear rack mechanism. When the reversing dead center is in the leading tooth of double-tooth meshing, the gear has the largest film thickness and the largest contact area. In addition, the synthetic radius of curvature and entrainment velocity become larger so the lubrication conditions have been improved. The results provide the theoretical basis and guidance for the reasonable design of the spur gear rack and the improvement of its lubricating performance.

中文翻译：

---

换向持续时间和换向啮合状态对往复正齿轮齿条弹流润滑的影响

往复式正齿轮齿条在换向死点附近容易出现润滑故障。采用Ree-Eyring润滑液、多重网格法和多重网格积分法计算压力分布、油膜厚度和油温升。与直线运动相比，往复换向运动的过程更复杂，润滑状态也更不稳定。分析了不同换向持续时间和换向啮合状态对润滑油膜的影响。结果表明，齿轮换向过程中油的厚度显着降低。缩短换向时间虽然可以提高润滑油膜的厚度，但会导致瞬时油温升高。所以，适当延长换向时间可以避免高温引起的轮齿损坏。换向持续时间越长，中心膜厚和中心压力的最小值越接近啮合出口区域。无论换向时间如何变化，最小润滑膜厚度都在换向死点位置。因此，换向死点仍是正齿轮齿条机构润滑失效的危险点。当换向死点在双齿啮合的前齿时，齿轮的油膜厚度最大，接触面积最大。此外，合成曲率半径和夹带速度变大，从而改善了润滑条件。