螺纹联接可靠性设计及其拧紧工艺研究

发布时间：2018-04-25 14:33

本文选题：螺纹联接 + 预紧力　；参考：《武汉理工大学》2012年硕士论文

【摘要】：螺纹联接结构作为汽车总装里面大量使用的基本结构,它的可靠性关系到汽车的总体性能好坏,特别是底盘部分的螺纹联接结构,更是关系到汽车的安全性能。螺纹联接结构保证其可靠性的关键在于螺纹紧固件的合理选择以及预紧力的合理控制。然而,由于国内汽车行业发展较晚,在螺纹紧固件的选择和预紧力的控制方面还存在不足。如预紧力分布散差过大,为保证螺纹的可靠联接,在设计时通常会选用比较大的安全系数,这样一来,虽然不会导致过载破坏,但是螺纹紧固件型号很大而所服役的预紧力相对很低,这样不仅不利于充分发挥螺纹紧固件的效能,同时预紧力相对过小,也不利于螺纹紧固件的抗松动性能和抗疲劳性能的充分发挥。同时,拧紧工艺的好坏也关系螺纹联接的质量好坏,倘若拧紧过程处于未受控状态,则拧紧之后螺纹联接的质量也会出现许多不可控的结果。本文从保证螺纹联接可靠性的角度出发,通过理论和试验相结合的方法,对螺纹紧固件的设计和拧紧工艺进行了系统的分析,从而为螺纹紧固件的合理设计选择以及预紧力的合理控制提供了一定的理论基础。本文的研究内容有以下几个方面： (1)研究了预紧力的控制方法,并基于应力-强度干涉理论,研究了螺纹联接可靠性的数学原理,并提出了可靠性的计算方法。 (2)通过拧紧试验得到了影响扭矩系数的关键因素,并提出了一种扭矩系数控制策略；研究了可靠性设计的经济优越性,至此,从技术和经济上说明了可靠性设计的优越性。 (3)为确保拧紧工艺的可靠性,运用统计过程控制的方法对螺纹联接的拧紧过程进行了系统分析,提出了保证拧紧工具精度的工艺流程,并且给出了静态扭矩控制图的绘制流程。
[Abstract]:As the basic structure used in automobile assembly, the reliability of threaded connection structure is related to the overall performance of the automobile, especially the thread connection structure of the chassis part, and also to the safety performance of the automobile. The key to ensure the reliability of thread connection structure lies in the reasonable selection of thread fastener and the reasonable control of pretightening force. However, due to the late development of domestic automobile industry, there are still shortcomings in the selection of threaded fasteners and the control of pretightening force. If the spread of pretightening force distribution is too large, in order to ensure the reliable connection of threads, a relatively large factor of safety is usually used in the design, so that, although it does not cause overload damage, But the type of threaded fastener is very large and the pretightening force in service is relatively low, which is not only unfavorable for giving full play to the efficiency of threaded fasteners, but also relatively small. It is also unfavorable to the loosening and fatigue resistance of thread fasteners. At the same time, the quality of screw thread connection is also related to the tightening process. If the tightening process is in an uncontrolled state, the quality of thread connection after tightening will also appear many uncontrollable results. In this paper, from the point of view of ensuring the reliability of thread connection, the design and tightening process of thread fastener are systematically analyzed by combining theory with experiment. It provides a theoretical basis for reasonable design and selection of thread fasteners and reasonable control of pretightening force. The research contents of this paper are as follows: 1) the control method of pretightening force is studied. Based on the stress-strength interference theory, the mathematical principle of thread connection reliability is studied, and the calculation method of reliability is put forward. 2) the key factors affecting torque coefficient are obtained by tightening test, and a torque coefficient control strategy is put forward, and the economic superiority of reliability design is studied, and the superiority of reliability design is explained technically and economically. In order to ensure the reliability of tightening process, the tightening process of screw thread connection is analyzed systematically by statistical process control method, and the process flow to ensure the precision of tightening tool is put forward, and the drawing flow of static torque control diagram is given.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH131.3

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