The vibrating screen is a commonly used equipment in mining machinery, and its vibration is mainly generated by the exciter. However, the operating conditions of the exciter are harsh, and it bears strong vibration impacts. Therefore, its bearings inevitably experience heating, burning, and other phenomena, seriously affecting the normal operation of the vibrating screen. This article shares the causes and solutions of bearing damage in vibrating screens.

1、 Design reasons
1. Unreasonable selection of bearings
The use type, maximum speed, installation fit size, clearance, self-lubricating performance and other requirements of bearings are relatively high. Ordinary bearings are prone to damage during harsh working conditions. If the selection of bearings is not appropriate in the initial design stage, the service life of bearings will be shorter.
Solution: Select specialized bearings. The commonly used vibrating screen bearings generally include cylindrical roller bearings and self-aligning roller bearings. Both have significant radial load-bearing capacity. The former also has a higher limit speed and strong load-bearing capacity for both dynamic and static loads, but requires a higher coaxiality of the bearing seat hole; The latter has good centering performance and can compensate for different shaft problems caused by bearing seat hole machining, but cannot withstand pure axial loads.
2. Unreasonable design of lubrication and sealing structure
At present, many exciter bearings in China adopt grease lubrication and labyrinth sealing structures, with a sealing gap generally between 1-2mm. However, in practical use, as the temperature of the exciter bearing increases, the viscosity of the lubricating grease gradually decreases, and the spindle rotates at high speed. The lubricating grease inside the labyrinth cover continuously leaks from the labyrinth cover, ultimately leading to bearing damage due to lack of lubrication.
Due to the unreasonable design of the lubrication and sealing structure, insufficient lubrication of the bearings is the main reason for the deformation and burning of the bearings caused by heating.
Solution: Use thin oil lubrication method, improve lubrication channels, and improve sealing structure. Many manufacturers currently use structures that combine thin oil circulation lubrication, labyrinth seals, and other non-contact seals.
3. Improper selection of matching between bearings and bearing seat holes
The tolerance of the fit between the bearing and the bearing seat hole is a key point in design. If a larger interference fit is selected, it will force geometric deformation of the bearing raceway shape and cause abnormal vibration during operation; If a larger clearance fit is selected, it will cause the outer ring of the bearing to slide relative to each other in the bearing seat hole, leading to rapid temperature rise and damage to the bearing.
Solution: Choose a reasonable fit tolerance. The inner ring of the bearing is fitted with a loose transition fit or clearance fit tolerance to the shaft, while the outer ring is fitted with a tight transition or slightly smaller interference fit tolerance to the bearing seat hole.
4. The design did not consider the expansion and contraction of the shaft
The operating temperature of the exciter is generally between 35-60 ℃, and the expansion and contraction of the shaft caused by thermal expansion and contraction cannot be ignored.
Solution: Design one end of the bearing as a transitional or clearance fit, so that the exciter shaft can slide relative to the inner ring during thermal expansion and contraction.
Solution: Design one end of the bearing as a transitional or clearance fit, so that the exciter shaft can slide relative to the inner ring during thermal expansion and contraction.

2、 Process reasons
1. The machining accuracy of the bearing seat hole is insufficient, and the two bearing seat holes on the same shaft are not concentric.
Solution: Use equipment with high machining accuracy to cut the two bearing holes in one go on a CNC boring and milling machine or machining center.
2. Uneven force is applied during bearing assembly. If uneven force is applied to the inner and outer rings of the bearing during cold assembly, it may cause a certain amount of deviation between the inner and outer rings of the bearing and the shaft or bearing hole, resulting in faster wear during operation.
Solution: Use specialized tooling to evenly compress the inner or outer rings during the bearing assembly process and assemble them in place.
3. If the bearings are not cleaned thoroughly during installation or if the lubricating oil is not clean, it may cause wear on the bearing raceway, increase the friction force of the rolling elements, and increase the temperature, resulting in bearing damage.
Solution: Clean the bearings thoroughly before assembly. Regularly replace the lubricating oil during the use of the exciter. The first lubricating oil change is after 150 hours of equipment use, and then every 1000 hours of operation.
4. Differences in the quality of grouped eccentric blocks, or large installation angle errors of grouped eccentric blocks, can cause vibration center vibration and cause bearing heating.
Solution: Adjust the mass and angle of the eccentric block to ensure symmetry and consistency. When installing or adjusting the excitation force, it is necessary to ensure that the angles of the eccentric blocks on the same axis are consistent, and the angles of the eccentric blocks on parallel axes are symmetrical.
3、 Reasons for use and maintenance
1. Due to uneven foundation or incorrect installation of the spring seat, abnormal movement of the screen body is caused, resulting in rotation or distortion of the vibrating screen, and heating and damage to the exciter bearings.
Solution: Adjust the foundation to make it level. When installing, first use a spirit level to measure whether the foundation is level. If it is uneven, it can be adjusted by adding a cushion plate to the foundation.
2. The large error in the center of gravity of the vibrating screen causes abnormal operation of the screen body, resulting in heating and damage to the bearings.
Solution: The ideal working state of the vibrating screen is that the whole machine runs smoothly and the amplitude is consistent in all parts. Therefore, it is necessary to strictly control the production and installation accuracy of the product, ensure that the center of gravity position is not offset, and try to feed as much as possible.