Virtual simulation experiment of fretting wear on the inner ring fitting surface of a vibration screen exciter bearing

The exciter of vibrating screens used in coal mines adopts self-aligning roller bearings with a large internal clearance, and its dynamic characteristics are more complex than those of traditional rotating machinery. The synergistic effect of multiple factors—excitation of the eccentric block, large internal clearance of the bearing, and elastic support of the elastic seat—induces vibrations between components. This produces a strong coupling effect and causes drastic variations in the internal load of the bearing. Under the dual action of intense external alternating excitation and internal local contact alternating stress, fretting wear is highly likely to occur on the mating surface between the bearing and the shaft, which poses a serious threat to the safe and reliable operation of coal preparation equipment. At present, research on fretting wear of bearing mating surfaces in vibrating machinery remains at a nascent stage.

Based on the typical vibration characteristics of vibrating machinery, this paper conducts a virtual simulation experiment on the fretting behavior between the inner ring fitting surfaces of the exciter bearing of a mining vibrating screen using the finite element simulation software ABAQUS. Through simulation, the load environment of the inner ring fitting surface under fretting behavior is reproduced, and the fretting wear model is further improved and established. In addition, the UMESHMOTION subroutine suitable for interference fit structures is developed using the ALE mesh adaptation technology in ABAQUS to simulate the wear damage caused by fretting behavior. This paper proposes evaluating the fretting wear of the bearing based on the wear rate with respect to the number of cycles and introduces a dynamic wear coefficient to optimize fretting behavior during the fretting process. Furthermore, the influence of different internal and external factors on fretting wear damage is analyzed, and the changing trends and wear mechanisms of fretting behavior on the inner ring fitting surface are explored.

The fretting simulation of the inner ring mating surface shows that (1) Fretting wear is mainly concentrated in the edge region of the inner ring and exhibits a symmetrical distribution; (2) An increase in rotational speed significantly accelerates the wear process and shortens the duration of the initial wear stage; (3) An increase in the mass of the eccentric block mainly accelerates fretting wear at the edge position and intensifies fluctuations in the wear rate, leading to an increased risk of early failure; (4) Either excessively small or excessively large interference fits aggravate local fretting wear, whereas an intermediate interference fit of 0.036 mm, within the reasonable range, results in the minimum wear amount and wear rate.

Experimental-based analyses of fretting wear on mating surfaces require the coordinated control of multiple variables. Continuous tracking of changes in fretting wear necessitates frequent disassembly; however, the disassembly and assembly of mating surfaces themselves can cause surface wear, which introduces interference. This makes it difficult to study fretting wear on mating surfaces through experimental methods. This paper proposes a research method based on simulation techniques that provides an effective solution to this problem. In addition, by implementing this simulation experiment, students can gain an in-depth understanding of the impact of fretting behavior on mating surface wear. From an engineering application perspective, this approach also enhances students’ understanding of theoretical knowledge related to mechanical design, such as mating mechanisms.