基于螺栓组残余预紧力一致性的研究

Study on consistency of residual pre-tightening force of bolt group

针对数控机床装配中螺栓组残余预紧力分布一致性差的问题,通过搭建实验台进行实验研究,获得拧紧顺序和分步拧紧策略对螺栓组残余预紧力的影响规律。首先,基于机床中常见的四螺栓连接结构,设计并加工出四螺栓连接结构实验件;然后,搭建实验台进行实验,分析拧紧顺序和分步拧紧策略对四螺栓连接结构残余预紧力的影响;最后,对两种分步拧紧策略进行对比分析。结果表明:3种拧紧顺序中,顺时针方向拧紧状态下四螺栓连接结构的残余预紧力一致性最好;随着拧紧步数的增加,螺栓组残余预紧力一致性变好;随着拧紧步数的持续增加,残余预紧力一致性提高不显著;随着首步拧紧比例的增加,螺栓组残余预紧力一致性变好;随着首步拧紧比例的持续增加,残余预紧力一致性提高不显著。该研究可以为提高机床装配质量和螺栓组预紧效果提供指导。

Aiming at the problem of poor consistency of residual pre-tightening force of bolt group in CNC machine tools assembly,an experimental bench was set up to study the effect of tightening sequence and step tightening strategies on residual pre-tightening of bolt group.First,based on the common four-bolt connection structure in machine tools,the experiment part of four-bolt connection structure is designed and fabricated.Secondly,an experiment platform was built to analyze the influence of tightening sequence and step tightening strategy on the residual pre-tightening force of the four-bolt connection structure.Finally,the two step tightening strategies are compared and analyzed.The results show that:among the three tightening sequences,the residual pre-tightening force consistency of the four-bolt connection structure is the best under the clockwise tightening condition.With the increase of tightening steps,the consistency of residual pre-tightening force of bolt group becomes better,but with the continues to increase of tightening steps,the consistency of residual pre-tightening force does not improve significantly.The consistency of the residual pre-tightening force of the bolt group becomes better with the increase of the first step tightening proportion,while the consistency of the residual pre-tightening force does not improve significantly with the continuous to increase of the first step tightening proportion.This study can provide guidance for improving machine tools assembly quality and bolt pre-tightening effect.