齿轮传动过程中产生的箱体与箱盖联接螺栓松动或断裂会严重影响齿轮运转的平稳性。本文建立了从完好到故障状态下斜齿轮减速器数字化样机参数化模型，利用多体动力学理论推导了数字化样机的多级齿轮传动系统的振动微分方程，采用数字化样机和内驱动求解模型研究了完好和故障状态下齿轮减速器的动态特性，获得了螺栓松动和断裂故障的振动特征，结果表明：与完好状态相比，螺栓故障会使得啮合频率幅值有所增大，螺栓松动时两级啮合频率幅值分别增大约19.8%和45.4%，螺栓断裂时两级啮合频率幅值分别增大约15.3%和2.1%。且螺栓松动会引起啮合频率两边出现边频带，从而为齿轮减速器早期故障诊断与智能运行维护奠定理论基础。

The looseness or fracture of the connecting bolts between the box and the box cover during the gear transmission process can seriously affect the smoothness of gear operation. This article establishes a parameterized model of a digital prototype of a helical gear reducer from intact to faulty states. The vibration differential equation of a multi-stage gear transmission system of digital prototype is derived using the theory of multibody dynamics. The dynamic characteristics of the gear reducer under good and faulty states are studied by using digital prototype and internal drive solution model, and the vibration characteristics of bolt loosening and fracture faults are obtained. The results show that compared with intact states, bolt failure increases the amplitude of meshing frequency, when the bolts were loosened, the magnitude of the engagement frequency increased by about 19.8% and 45.4%, respectively. when the bolts were broken, the magnitude of the engagement frequency increased by about 15.3% and 2.1%. And loose bolts can cause sidebands on both sides of the meshing frequency, laying a theoretical foundation for early fault diagnosis and intelligent operation and maintenance of gear reducers.