Abstract:  Wheel hub bearings are important components on the chassis of automobiles. In order to reduce fuel or electricity consumption per unit mileage of automobiles, the influence of environmental temperature on the friction torque and friction energy loss of wheel hub bearings during driving were studied. Firstly, two theoretical calculation formulas for the friction torque of wheel hub bearings were presented, and a calculation method for evaluating the friction energy loss of wheel hub bearings was proposed. Then, based on the formulas and relevant principles, a theoretical analysis was conducted on the impact of environmental temperature on the friction energy loss of wheel hub bearings, and preliminary conclusions were drawn. Finally, using the most advanced international wheel hub bearing friction torque and energy loss testing machine, a specific road spectrum test program was set up, and test verification was conducted under different temperature environments under constant vehicle speed, Chinese road spectrum China light-duty vehicle test cycle-passenger(CLTC-P), and European road spectrum new European driving cycle(NEDC)test conditions. The research results show that when a car is driven at a constant speed, the higher the ambient temperature, the smaller the friction torque of the wheel hub bearing. The friction torque of the wheel hub bearing is about 50% lower in a high temperature environment of 40℃ than in a low temperature environment of -20℃. Whether a car is driven on the CLTC-P or NEDC road spectrum, the higher the ambient temperature, the lower the friction energy loss of the wheel hub bearing. In a high temperature environment of 40℃, the friction energy loss of the wheel hub bearing is about 60% lower than that in a low temperature environment of -20℃. This is also one of the reasons why the fuel or electricity consumption per unit mileage of a car is higher in winter than in summer.
Key words: rolling bearing; automobile wheel hub bearing; friction torque; lubrication performance; bearing working clearance; ambient temperature; road spectrum test