大重型数控转台静压主轴承载及蜗轮蜗杆啮合侧隙优化

大重型数控转台采用静压轴承径向定位,双导程蜗轮蜗杆精密分度。蜗轮蜗杆啮合侧隙与静压主轴轴承的刚性耦合,影响转台分度精度、重复定位精度和动态性能。基于齿轮分配器的工作原理,建立了大重型数控转台静压主轴轴承的数学模型,分析了各个油腔的压强对应关系,阐明了转台径向承载能力、承载刚性与偏心率的关系。借助激光干涉仪测量转台分度曲线,针对蜗轮蜗杆啮合侧隙的不均匀的现状,推导了啮合侧隙的最大值,提高了转台的重复定位精度及精度保持性。

Optimizing bearing capacity of hydrostatic main shaft bearing,worm and gear backlash

The large NC rotary table was positioned by hydrostatic main shaft bearing in the radial direction,and driven by dual lead worm and gear backlash related to radial rigidity of hydrostatic main shaft bearing.It had effects on indexing accuracy,repeated position accuracy and dynamic performance.Based on the principle of gear flow divider,a mathematical model of the hydrostatic main shaft bearing was established on the large NC rotary table.After analyzing relationship between pressure of oil chamber and eccentricity of the table,the radial load capacity and the rigidity were analyzed.Measurement results of the table by laser interferometer showed that worm and gear backlash was uneven.With the calculated maximum gear backlash the indexing accuracy and the repeat position accuracy of the table were increased.