In vibrating screen, the working condition of bearings is generally very severe, which will cause the vibration of bearing. And the vibration of bearing may affect the screening effect and reduce the service life of vibrating screen. Many customers wonder how can we control and reduce the bearing vibration. Here, we firstly focus on the analysis about factors affect the bearing vibration in vibrating screen.
At present, the vibration exciter in vibrating screen is generally eccentric shaft vibration exciter and box vibration exciter. The eccentric shaft vibration exciter is convenient to install and adjust, but its cost is relatively higher and the eccentricity cannot be adjusted. The box vibration exciter adopt fan-shaped eccentric block with relative position can be adjusted. In this case, it can achieve the adjustment of excited force and the adjustment of vibration amplitude.
While the vibration exciter works, the centrifugal force produced by eccentric mass makes the eccentric shaft bend, which will lead to the relative deflection between the inner and outer ring of bearings. In this case, there will be vibration caused by eccentric. So the inertial force and inertia couple produced in the operation process will cause the dynamic reaction and vibration of bearings, breaking the stability of bearings and some other spare parts and causing high frequent vibration.
The vibrating system formed by bearings and eccentric system can be considered as single-degree-of-freedom system. The driving shaft and driven shaft of bearings both have some certain resonant frequency. If the vibration frequency is close to the resonant frequency, then there will be sympathetic vibration. Besides, since there is centrifugal inertial force because of eccentric, so there will be bending vibration produced.
The Geometric Accuracy Of Bearings
The strong excited force of vibrating screen makes the bearings bear large radial force, leading to the great vibration of vibrating screen. The higher the geometric accuracy of bearings, the smaller the vibration will be. The percent ripple on the raceway especially on the surface of rolling element has most important influence on the vibration. The clearance of rolling element, retainer and rolling surface of outer and inner ring and their relative movement will both cause the vibration of bearings. The spin frequency of rolling element is very high, so to reduce the vibration of bearings, we need firstly improve the surface machining accuracy of rolling elements.
To be continued