数控龙门镗铣床滑枕热特性分析

滑枕是影响数控龙门镗铣床加工精度的关键部件。针对切削加工中存在的实际问题,确立导致滑枕热变形的热源,对轴承生热率进行计算,建立热变形数学模型;对滑枕进行热性能分析,并对主轴轴系结构进行改进。结果表明:滑枕的最高温度在主轴轴承支承处,为64.13℃;滑枕的最大的热变形在主轴轴承支承端,为38.9μm;采用冷却套结构、后轴承自由支承方式,减小主轴、滑枕热变形,从而提高数控龙门镗铣床加工精度。

Thermal Characteristic Analysis of Ram of CNC Gantry Milling and Boring Machine

Ram is the key part influencing the machining accuracy of gantry type boring and milling machine .Aiming at actual problems in cutting , the heat sources causing thermal deformation of ram were found out .The heat generation rate of bearings was cal-culated, and the mathematic model of thermal deformation was set up .The thermal performance on the ram was analyzed , and the structure of bearings of the spindle unit was improved .The result shows that the highest heat point of 64.13℃is at the bearing support part, and the biggest thermal deformation part which is 38.9μm, it is at the spindle bearing support end .Using the cooling sleeve unit and rear bearing free support structure can reduce the thermal deformation of spindle and ram , and so to improve the machining accura-cy of gantry type boring and milling machine .