The linear vibrating screen uses vibration motor excitation as the vibration source, so that the material is thrown up on the screen and moves forward in a straight line. The material enters the feeding port of the screening machine evenly from the feeder and passes through the multi-layer screen, then it screens several sizes of oversize and undersize product, which are discharged from the respective outlets. It has low energy consumption, high output, simple structure, easy maintenance, fully enclosed structure, no dust overflow, automatic discharge, and is more suitable for assembly line operation.

1. Eccentric vibration
The vibration exciters used in the linear vibrating screen are mostly eccentric shaft exciters and box exciters. The eccentric shaft exciter is easy to install and adjust, but the cost is high, and the eccentricity is not adjustable. The box exciter adopts a fan-shaped eccentric block with adjustable relative position, which can adjust the excitation force to change amplitude.
The centrifugal force generated by the eccentric mass bends the eccentric shaft, resulting in the relative deflection of the inner and outer of the bearing. Since the eccentricity generates vibration caused by the frequency conversion and its various harmonics, the inertial force generated during the operation will cause the dynamic reaction force and vibration of the bearing, destroy the smooth working state of the bearing and other components, and generate high-frequency vibration. The research shows that when the vibration frequency of the exciter bearing is the same as the natural frequency of a certain order of the elastic vibration of the screen box, it will cause strong vibration of the screen box elastic body.
A vibration system consisting of a bearing and an eccentric system can be considered as a single system. Both the bearing drive shaft and the driven shaft system have a certain resonant frequency. If an excitation frequency is close to the resonant frequency, resonance occurs. Furthermore, since the eccentricity has a centrifugal inertial force, bending vibration occurs, and if the rotational speed approaches a critical value, bending resonance occurs.
2.Bearing accuracy
The linear vibrating screen has a large excitation force, which causes the bearing to withstand a large radial force, resulting in strong vibration. The higher the bearing accuracy, the smaller the vibration. The raceway, especially the waviness of the surface of the rolling element, has the greatest influence on the vibration of the bearing. The clearance between the rolling element and the cage and the rolling surface of the inner and outer rings and their relative motion can cause the vibration of the bearing, which is due to the higher spin frequency of the rolling element. The working surface is in contact with the inner and outer raceways at the same time, and the vibration generated by the rolling elements, the ferrules and the cage is approximately 4:3:1. Therefore, reducing the bearing vibration should first improve the surface machining accuracy of the rolling elements.
3. Bearing radial clearance
If the radial clearance is too large or too small, the bearing system will generate a large vibration. If the radial clearance is too small, linear vibrating screen will cause high-frequency vibration, and if it is too large, it will cause low-frequency vibration. The test results of the linear vibrating screen bearing show that the radial clearance is too large, reducing the radial natural frequency of the bearing elastic system, and it is easy to generate resonance and generate large low-frequency vibration. This is because a large acceleration is generated at the impact point of the rolling elements and the ferrule. At the beginning of the impact, high-frequency compression waves that are independent of mechanical quality and shape of the object are generated and transmitted to the inside of the metal. At the later stage of the impact, a mechanical vibration lower than the frequency of the impact compression wave is generated by the mechanical force. Therefore, a large radial clearance will increase the vibration of the bearing in the passband.
4. Coordination
The coordination of the outer ring and the support hole will affect the transmission of vibration, and the tight fit will force the deformation of the raceway, increase the shape error, and increase the vibration. A looser fit can cause damping of the oil film in the gap. The material properties of the outer ring and the bearing housing are quite different, especially the rubber damping ring is placed between them to suppress the transmission of vibration.
5. Friction and lubrication
The bearing is the main vibration source that is difficult to control by the linear vibrating screen. Since the linear vibrating screen is maintained by a large excitation force, the radial force of the bearing is very large, and the linear vibrating screen is very large during the working process. The exciting force will cause elastic vibration of the bearing system. If the lubrication is poor, a large friction will occur to make the bearing temperature rise too high, and the thermal expansion is too large, so that the radial clearance is significantly reduced, thereby intensifying the friction and further increasing the temperature rise.