标准的普通螺纹其螺峰角2α=60°或55°在轴向反复冲击受力的情况下往往较易引起松弛。据日本螺丝研究协会杂志报导,对螺纹受冲击而引起松弛的情况已经开展了研究并已获得成果。研究中使用的试验装置如图1所示。上下套筒用M12螺栓与螺母连接一体并在导向套内以一定高度反复作自由落体运动。螺纹受轴向外力冲击发生松弛时引起预加锁紧力的下降,可通过螺栓杆上所贴附的应 The standard ordinary thread of its crest angle 2α = 60 ° or 55 ° in the axial repeated impact stress conditions are often more likely to cause relaxation. According to the Japan Society for Screw Research, it has been reported that the thread slack caused by the impact has been studied and has achieved results. The experimental setup used in the study is shown in Figure 1. Upper and lower sleeve with M12 bolts and nuts connected in one and the guide sleeve to a certain height repeated free-fall movement. Threaded external impact by the impact of slack caused by pre-locking force decreased by the bolt can be attached to the rod should