Choosing the Right Bearings for Motors: Load Impact and Selection Principles

How significant is the relationship between bearing selection and motor load?

For motor bearings, whether you're a motor manufacturer or a motor user, it's well known that for heavy-duty motors, cylindrical roller bearings are typically used on the motor shaft extension end. For especially large and heavy-duty motors, sliding bearings are often employed.

In practice, you may notice that some motors exhibit noticeable vibration when unloaded, but become stable when under load. This leads us to today's discussion on the relationship between bearing selection and load size.

For the shaft extension end of heavy-duty motors, a two-bearing structure is often used, with cylindrical roller bearings on the shaft extension end and ball bearings on the non-shaft end. In cases where axial positioning is critical, a three-bearing structure is employed, where the shaft extension end has a dual-bearing setup with one ball and one roller bearing, and the non-shaft end uses ball bearings. For standard-load motors, particularly smaller ones, ball bearings are commonly used at both ends of the motor, following the basic principle of selecting bearings based on the motor's load.

In addition to bearing type, choosing the right bearing size is crucial. The bearing's load capacity should match the motor's load, with adjustments made based on the motor's actual operating conditions, increasing or decreasing bearing size accordingly. Reputable bearing manufacturers are capable of providing tailored bearing selection solutions, adjusting specifications or dimensions to suit the motor's operating conditions.

In fact, different motor transmission methods have varying load requirements for bearings. For example, pulley drives, couplings, and gear drives all impose different loads on bearings. In coupling transmission, the relationship between bearing load and torque is relatively minor. For motors with pulley drives, the bearing load is affected by belt tension and pulley size, while in gear drives, the bearing system is directly influenced by the torque.