增压器是一种高速旋转机械，工作环境十分复杂。在装配过程中，压气机轴端螺母的拧紧工艺会影响所获得预紧力的均匀程度，如果轴端螺母松动，会导致增压器故障。针对这一问题，首先，采用压气机轴端螺母预紧力范围评价模型，结合压气机热力计算结果，确定预紧力范围；然后，根据设计值确定扭矩法及扭矩转角法拧紧试验规范；最后，基于自主开发的紧固试验装置，开展压气机轴端连接结构模拟样件拧紧试验，研究了不同拧紧工艺对轴端预紧力的影响。结果表明：保证压气机轴端结构正常工作所需轴端预紧力范围为18.16~31.03 kN；采用扭矩转角法拧紧得到的预紧力标准差约为扭矩法的25%，使用扭矩转角法有利于降低预紧力分散程度，且采用扭矩转角法拧紧更接近设计中值，有利于提高预紧力控制精度。

The supercharger is a kind of high-speed rotating machinery, and its working environment is very complex. During the assembly process, the tightening process of compressor shaft end nut will affect the uniformity of the obtained preload. If the shaft end nut is loose, it will cause the supercharger to fail. In order to solve this problem, the evaluation model of the pre-tightening force range of compressor shaft end nut was used, and the thermal calculation results of compressor were combined to determine the pre-tightening force range. Then, according to the design value, the tightening test specification of torque method and torque-rotation angle method were determined. Finally, based on the self-developed fastening test device, the tightening test of the simulated sample of compressor shaft end connection structure was carried out, and the influence of different tightening processes on the pre-tightening force of shaft end was studied. The results show that the required shaft end preload range is 18.16-31.03 kN under the condition of ensuring the normal operation of compressor shaft end structure. The standard deviation of the pre-tightening force of torque-rotation method is roughly 25% of torque method. The use of torque-rotation method is beneficial to reduce the dispersion degree of pre-tightening force, and the tightening of torque-rotation method is closer to the design median, which is beneficial to improve the pre-tightening force control accuracy.