Effect of Oil Film Parameter on Vibration Acceleration and Electrical Pitting of Small Ball Bearing

Abstract

The authors have studied the current density and voltage at which electrical pitting occurs in a small ball bearing. Some current-applying bearing tests in previous studies showed an interesting tendency for the vibration of bearings to increase when they were lubricated with a thicker oil film. In this study, the oil film parameter is intentionally changed, and its effects on the generation of pitting and vibration acceleration are experimentally investigated. Ball bearing endurance tests involving 500 h of operation were performed by applying a direct electric current with various rotational speeds, and with various base oil viscosities of grease and surface roughness of the raceway. The test results clarified that electrical pitting appeared more clearly and the vibration due to damage became severer with increasing oil film parameter. Although a larger oil film parameter is generally advantageous for increasing bearing life, it is undesirable from the standpoint of preventing electrical pitting.

An Experimental Study of Surface Damage on Rolling Bearings in Low Lambda Conditions

“…Surface damage on rolling bearings is believed to be influenced by a variety of factors. Load, surface roughness, oil viscosity, speed, sliding, temperature, hardness, and contamination have all been identified as factors that can contribute to surface damage [20][21][22][23]. In this study, the parameters that directly affect the oil film condition, including oil viscosity, rotational speed, and surface roughness, were selected and prioritized.…”

Study on Vibration Frequency for Ball Bearing Damaged by Electrical Pitting

“…In our previous paper (4) , the occurrence condition of a ridge mark was clarified for the same bearing as applied here. The formation of a ridge mark considerably depends on the oil film parameter Λ between the surfaces of the rolling element and the inner raceway.…”

“…No. 4,2013 integrals of the number of rolling elements (Z=7) increase with time. Table 3 represents the relationship between the number of undulations per round and the vibration frequency for a rotation speed of 3600 min -1 .…”

“…In this research, the experimental instruments applied in a previous study (4) were improved to measure both axial and radial vibration accelerations. Figure 2 shows the experimental instrument and Figure 3 its schematic diagram.…”

“…However, recent research has clarified that the value of the oil film parameter between a rolling element and the raceway is required to be larger than 3 to form the ridge mark, Moreover, it was also clarified that the vibration increased, but the ridge mark was not formed even if the oil film parameter was less than 3 (4) . The vibration frequency in a rolling bearing depends on the geometrical form errors of each bearing part (5) .…”