1. Source of vibration Through analysis and research and related data, we can see that there are three main aspects that cause the vibration of the PU timing belt drive: (1) Incorrect manufacturing and installation, including: ① The eccentricity and mismatch caused by unreasonable machining of the center hole of the pulley and the cone on the shaft; ② The eccentricity caused by the inappropriate machining dimensions of the cone and shaft. (2) The design is unreasonable, including: ① The actual working condition of the pulley is different from the design working condition, such as the fan working in the vicinity of the first or second critical speed for a long time; ② The design strength of the footing structure is not the same. (3) Vibration caused by other factors: ①The belt is too worn and too loose or the belt is too tightly installed; ②The equipment runs for a long time and the shaft is slightly bent or the hub is worn and deformed; ③The anchor bolts are loose; ④Vibration nearby Secondary resonance induced by the source. 2. Vibration analysis Most of the rotating equipment has been tested for dynamic and static balance and test run before leaving the factory. It will vibrate when it is used for a period of time on site or when it starts to operate at the beginning of the installation, mainly due to poor alignment or weak foundation during installation or disassembly and inspection Unstable operation and poor alignment are the main factors. Common angular misalignment, parallel misalignment, a combination of two misalignments, and misaligned bearings are crooked on the shaft.