What does PV value represent in EPB bearing selection, and how is PV value used to guide selection?

PV value is the product of bearing load P and linear speed V. It is a core indicator in plain bearing selection. The PV value is inversely proportional to bearing life. The closer the PV is to the material limit, the faster the bearing wears and the shorter its life. The manual provides the allowable PVperm calculation formula, which is related to bearing wall thickness, length, friction coefficient, heat conduction between shaft and bearing, temperature rise ΔT, and two major correction factors y1 (intermittent operation) and y2 (lubrication method). y1 intermittent correction: the equipment does not work continuously, and friction heat is dissipated during the stop phase, so the allowable PV can be increased. The shorter the running time, the higher the y1 coefficient. y2 lubrication correction: dry running y2=1, grease lubrication y2=2, water lubrication y3=3, oil lubrication y2=4. Lubrication reduces friction heat generation and significantly increases the allowable PV value. Different EPB grades have different limit PV values. High-temperature grades such as EPB5Z and EPB10 can withstand high PV; general EPB base grades have a lower PV upper limit. Typical applications: the intermittently oscillating automotive seat mechanism EPB3M. Under intermittent conditions, y1 is increased, so a medium-PV material can be selected. For underwater equipment EPB8, water lubrication y2=3, so the allowable PV can be increased. Selection cannot only look at single parameters such as temperature and load; PV must be calculated. The official online query tool can input load, speed, and temperature for theoretical verification, but this is only for reference. Prototypes must be tested and verified. Theoretical calculation cannot cover complex on-site factors such as dust, media, and impact.