Bearings For Vertical Motors

Deep groove ball bearings cannot sustain heavy axial loads. Therefore, angular contact ball bearings (commonly referred to as thrust bearings) are mainly adopted as locating bearings in vertical motors. Whether single-row or double-row design, angular contact ball bearings feature high axial load capacity and good speed performance. Today we will discuss bearings for vertical motors.

Classification and Application of Angular Contact Ball Bearings

Angular contact ball bearings include 7000C type (contact angle α=15°), 7000AC type (α=25°) and 7000B type (α=40°). Generally, the inner and outer rings of this type of bearing are non-separable. They can bear combined radial and axial loads as well as axial load in one single direction. Its capacity to carry axial load is determined by the contact angle: the larger the contact angle, the higher the axial load capacity. This bearing can limit the axial displacement of the shaft or housing in one direction.

Single-row angular contact ball bearings are widely applied in machine tool spindles, high-frequency motors, gas turbines, centrifuges, front wheels of light vehicles, pinion shafts of differentials, booster pumps, drilling platforms, food machinery, dividing heads, butt welders, low-noise cooling towers, electromechanical equipment, coating equipment, machine tool slideways, arc welders, etc. Single-row angular contact ball bearings are commonly used for vertical motors.

Single-row Angular Contact Ball Bearings for Vertical Motors

Bearing selection for vertical motors is related to motor power and frame size. Vertical motors of frame size H280 and below generally adopt deep groove ball bearings, while angular contact bearings are required for H315 and above. High-precision and high-speed bearings usually adopt a 15° contact angle. The contact angle will increase under axial force.

When angular contact ball bearings are used in vertical motors, they are normally fitted at the non-drive end to meet the requirement that the drive-end bearing withstands radial force. However, angular contact ball bearings have strict directional mounting requirements. It must be guaranteed that the bearing can bear downward axial force, consistent with the gravity direction of the rotor.

Simply put: if the angular contact bearing is mounted on the upper side, it shall "suspend and hold" the rotor; if fitted on the lower side, it shall "support and carry" the rotor.

On the premise of meeting the above functional requirements, the assembly manufacturability of the end cover must also be considered. That is, the external force during end cover assembly must align with the axial force the bearing can withstand (the inner ring and outer ring of angular contact ball bearings can bear axial forces in opposite directions). Otherwise, the bearing may be disassembled and damaged.

Mounting of Bearings for Vertical Motors

Following the above rules: For vertical motors with shaft-up configuration, angular contact bearings are installed at the non-drive end. This satisfies axial load requirements and ensures the assembly manufacturability of the end cover. For vertical motors with shaft-down configuration, angular contact bearings are also mounted at the non-drive end. Corresponding protective measures must be taken during end cover assembly on this end to prevent bearing damage.