Which of the following is an example of a radial bearing?

• A. Thrust ball bearing in a conveyor roller (thrust)
• B. Magnetic bearing in a wind turbine
• C. Spherical roller bearing used in a clutch
• D. Ball bearing in a pump (radial)

Answer: (D)

Radial bearings are designed to carry loads that act perpendicular to the shaft, allowing the shaft to rotate with minimal friction. In a pump, the rotating impeller creates a sideways, or radial, load on the bearing as the fluid pressure pushes on the impeller. A ball bearing is built to support that radial load and transfer it to the housing, making it a classic radial bearing arrangement.

Thrust bearings, by contrast, are built to carry axial loads along the shaft, not sideways, so they are not the right example for a radial bearing. Magnetic bearings are a different technology that can handle radial and axial loads electronically or electromagnetically, but they’re not the conventional mechanical radial bearing described here. Spherical roller bearings can take substantial radial loads and some axial load and are used in heavy-duty applications, but their typical use isn’t the straightforward radial-bearing example found in a pump.

So the ball bearing in a pump clearly illustrates a radial bearing.