油膜包覆异型条材无划伤精密矫直方法研究

Study on No-Scratch Precision Straightening Methods of Profiled Bars with Oil Film Coating

为实现化油器针阀用异型条材无划伤精密矫直,基于弹流润滑理论,提出异型条材包覆油膜辊式矫直方案。通过对异型条材截面几何特征分析,提出与异型条材截面相包容且有利于油膜生成的矫直辊形设计方法,保证矫直过程中异型条材与矫直辊接触承载区域内包覆油膜形成。利用Dowson-Higginson公式建立油膜厚度与矫直参数、润滑油动力粘度之间量化关联模型,分析最小油膜厚度影响函数,确定实现异型条材无划伤精密矫直工艺参数,并进行试验验证。结果表明:油膜包覆异型条材辊式矫直方法能够实现无划伤精密矫直,满足针阀数控加工前直线度精度要求。

In order to realize no scratch precision straightening of profiled bars used for carburetor valve,based on elastic-flow theory,roller straightening scheme for bars coated with oil film was presented. By analyzing the geometric features of profiled bars,straightening roller shape design methods matching with the cross section of bars and favoring oil film formation was proposed to guarantee the oil film coating formation at the line contact bearing area between bars and rollers. The quantitative relationships between the minimum thickness of oil film and straightening parameters,lubricating oil dynamic viscosity were built using the Dowson-Higginson formula. The influence function on minimum thickness of oil film was analyzed to determine the precision technology parameters which can realize no scratch straightening for profiled bars and the experimental verification was conducted. The results show that the roller shape design methods for profiled bars with oil film coating can realize no scratch precision straightening and satisfy the straightness accuracy requirements of needle valve before NC machining.