Reasons for frequent damage of vibrating screen exciter

Date: Dec. 03, 2021

The exciter is a key component of the vibrating screen. During production, vibration exciters often have troubles such as heating and burning of bearings. There are 4 sets of vibrating screens in the 1000t/h crushing station equipment, and 8 sets of vibration exciters are matched with them. These exciters are large in size and heavy in weight. During operation, the inner cavity bearing of the vibration exciter often appears high temperature, burned or even locked, which causes the vibration exciter to not work normally, which directly affects the production of the crushing station.

Especially in the harsh season of high temperature and heat and full of wind and sand, the failure rate of the vibration exciter has increased significantly. In order to ensure the normal operation of the exciter, the abnormal problems of the exciter must be improved.

The working principle of the exciter

This model is ZYQZ series double-shaft type vibration exciter. It is driven by an external motor to drive the two shafts (long and short) of the double-shaft type vibration exciter, and rotate in reverse and synchronously. It is produced by eccentric blocks on the two axes. The resultant centrifugal force drives the vibrating screen to move in a straight line. The vibration exciter is fixed on the support plates on both sides of the vibrating screen, the motor driving the vibration exciter is fixed on the outer support, and the motor does not participate in vibration.

Failure cause analysis

The failure exciter was checked and repaired. After disassembly and inspection, it was found that the bearing (model 22330CA/W33C4) was seriously deformed and damaged. At the same time, the inner and outer rings of the bearing were discolored and blacked, and the bearing could not rotate and locked.

For the above-mentioned failures, the reasons are as follows:

(1) The bearings in the inner cavity of the vibration exciter are lubricated with grease. The grease between the inner and outer ring raceways and the rollers of the bearing cannot be fully lubricated and is lack of oil.

(2) When the bearing is running under insufficient lubrication conditions, it generates heat and generates high temperature. The temperature reaches 110°C to 120°C. The bearing roller cage is deformed and falls apart and cannot rotate normally.

(3) The radial working clearance of the bearing is too large, which affects the service life of the bearing.

Improvement measures

Improvement of the oil seal structure of the exciter

According to the analysis of the cause of the failure of the vibration exciter, combined with the harsh environment of the equipment site of our company, the vibration exciter should be fundamentally modified, and the original method of manual grease filling should be changed to a thin oil lubrication station. The circulation method realizes sufficient and effective lubrication of the internal bearings of the exciter.

Improvement of the lubrication system

In order to ensure that the vibration exciter bearing is lubricated in place, while completing the improvement of the oil seal structure of the vibration exciter, the lubrication system needs to increase the working lubrication part and the thin oil station circulation part.

Control the radial clearance of the bearing within a suitable range

The size of the bearing clearance directly affects the service life of the bearing. If the radial working clearance of the bearing is too large, the oil film will be difficult to form, insufficient lubrication, and noise; if it is too small, it will easily cause the bearing to heat up and burn the bearing during operation. Therefore, when the bearing is selected and installed, the radial working clearance control is very important, and it should be controlled within 8μm～50μm.