Impact crushers work under harsh conditions for a long time and the rotor bearings are easily damaged. According to the feedback from Deya Machinery’s clients and experience of Deya Machinery’s technical team, this paper would like to discuss several aspects to reach improve the bearing life.
1. Correct selection of bearing type, reasonable calculation of bearing life
Because of the double-row radial spherical roller bearings have the advantages of strong bearing capacity and good alignment performance, so it is mostly used as the rotor bearing of impact crusher at home and abroad. After a long period of practice, Deya Machinery technical personnel believe that the empirical formula P=3G (G is the weight of the rotor body) to calculate the equivalent load is applicable. And the expected calculated life of the bearing can be 10000 hours as appropriate.
2. Changing the force state of the rotor bearing
The impact load acting on the bearing depends on the impulse acting on the rotor and the stiffness of the elastic system (plate hammer, rotor body, shaft and its support). Increasing the bearing body support flexibility will reduce the impact load acting on the shaft and bearing, thus increasing the bearing life. So we add in the appropriate thickness of rubber plate between the bearing housing and the support frame, absorbing part of the vibration, so that the shaft bearing force condition has been improved.
Industrial rubber sheet has very superior pressure resistance and cushioning performance, and its elastic modulus is rapidly increasing with the increase of pressure. As a result, this material can withstand large deformations under impact loads without damage. The deformation rate of this rubber is about 30%, depending on the weight of the impact crusher rotor body and working conditions, a rubber plate of 10 to 15 mm thickness can be selected.
3. Correct selection of the rotor bearing fit relationship
The rotor bearing of impact crusher is mainly subjected to impact load and rotor body weight when working. The size of the load on each rolling body of the bearing is not the same, in the impact load and the gravitational force of the combined line of action of the rolling rest of the greatest force, at the same time, the inner and outer ring raceway is also in contact with the rolling body here when the greatest force. As the inner ring work non-stop rotation, each contact point on the whole raceway will pass this maximum force point in turn, so the inner ring with tighter, the raceway will not happen a contact point to stay in this maximum force point of the danger. The outer ring, because there is only one fixed point will always stay on this point of maximum force, the whole raceway is very uneven force. If the fit is looser, it is possible to produce a small circumferential displacement under the impact, which improves the bearing outer ring force situation and prolongs the life.
4. Improve the balance accuracy of the rotor body
The rotor of the impact crusher has a relatively large weight and high speed. The casting deviation of the rotor and the weight deviation caused by the installation of the plate hammer make the rotor rotate with unbalanced centrifugal force, which causes the machine to vibrate and leads to the destruction of bearings and other machine parts. Therefore, how to make the rotor run in balance is an important issue.
After investigation and research, we believe that it is better to adjust the balance by the following methods. If the diameter of the rotor body is relatively small, it can be balanced by changing the quality of the blocking plates on both sides of the rotor body. If the diameter of the rotor body is relatively large, it is better to weld the counterweight on the rotor on the outer wall of the body. Some rotor bodies are also made of several thick steel plates or cast steel plates and spacer sleeves stacked side by side, such as the latest impact crusher produced by Henan Deya Machinery Equipment Co., Ltd. The balance accuracy of this structure itself is relatively high.