Investigation of the Effect of Contact Seal Geometry on Frictional Moment in Ball Bearings

Due to their simple design and versatility, rolling bearings are widely used in various industrial and engineering applications. One of the key parameters characterizing ball bearings is the frictional moment (also referred to as resisting torque). Excessive torque values can increase energy consumption, which is undesirable from an energy efficiency standpoint. In response to the increasing demand for energy-efficient solutions, studies on the frictional moments of ball bearings are gaining particular significance. Numerous research studies have been conducted to investigate the factors that affect this parameter in rolling bearings. However, in the case of rolling bearings with contact seals, accurately evaluating these relationships is challenging due to the instability of frictional moment values observed during measurements. Therefore, this paper presents a study aimed at evaluating the impact of rubber seal geometry (specifically roundness and waviness deviations) on the value of friction torque in 6304-type ball bearings. It is important to note that manufacturers employ various types of seals. This study presents a preliminary qualitative assessments of the manufacturing quality of rubber contact seals from selected producers. Form deviations of the rubber seals were analyzed using a multisensor O-Inspect coordinate measuring machine. The frictional moment of rolling bearings was measured using a dedicated measurement system developed at Kielce University of Technology. Measurements were conducted under two axial load values (70 N and 135 N) and two rotational speeds (50 rpm and 1800 rpm). Based on qualitative observations, the dominant factor influencing the frictional moment magnitude was identified.