两种新型金属自攻钉的紧固性能研究

Fastening Properties of Two New Metal Self-Tapping Screws

自攻钉是一种高强度、同时具有自攻和紧固功能的紧固件。不同的螺纹结构对紧固性能有不同的影响。通过设计拧紧试验和防松试验,详细分析了两种自攻钉的安装扭矩选择、扭矩效率以及防松性能,为工程应用中金属自攻钉的选型提供参考。通过对比发现:同一规格的“I型”自攻钉攻入扭矩比“II型”的低,“I型”自攻钉具有更大的扭矩选择窗口,安装的安全因子更高;同一规格的“II型”自攻钉扭矩效率比“I型”的高,增加相同的夹紧力,“II型”自攻钉消耗的扭矩更小;值得注意的是,由于“I型”自攻钉的低攻丝扭矩优势,低夹紧力的安装需求下,“I型”自攻钉需要的扭矩更小,而高夹紧力的安装需求下,“II型”自攻钉需要的扭矩更小;与铝合金材料的螺母配合时,两种自攻钉与公制螺钉相比,都具有很好的防松性能,但是同一规格的“II型”自攻钉和“I型”自攻钉相比,“II型”自攻钉拥有更好的防松性能。

Self-tapping screw is a high strength fastener with both self-tapping and fastening functions.Different thread structures have different effects on fastening performance.Through the design of tightening test and anti-loosening test,the installation torque selection,torque efficiency and anti-loosening performance of two kinds of self-tapping screws were analyzed in detail,which provided reference for the selection of metal self-tapping screws in engineering.By comparison,it is found that the“Ⅰ”type self-tapping torque is lower than that of the“Ⅱ”type self-tapping screw in the same specification.The“Ⅰ”type self-tapping screw has a larger torque selection window and a higher safety factor for installation.The“Ⅱ”type self-tapping screw torque efficiency is higher than“Ⅰ”type self-tapping screw with same specification.Increasing the same clamping force,the torque consumption of“Ⅱ”type self-tapping screw is smaller.It is worth noting that“Ⅰ”type self-tapping screw needs smaller self-tapping torque in lower clamping force installation requirements,which is owning to its lower self-tapping torque;“Ⅱ”type self-tapping screw needs smaller torque in high clamping force installation requirements.Compared with metric screws,both kinds of self-tapping screw have good anti-loosening properties,but“Ⅱ”type self-tapping screw has better anti-loosening properties than that of“Ⅰ”self-tapping screw.