What type of bearing is designed to support a radial load only?

The correct answer is journal bearing. A journal bearing specifically supports radial loads, which are forces that act perpendicular to the axis of the shaft. In a journal bearing, a shaft rotates within a bearing sleeve or housing, and the load is primarily supported by the hydrodynamic film of lubricating oil that forms between the shaft and the bearing surface. This design effectively handles radially applied loads while minimizing friction and wear.

In contrast, thrust bearings are designed to handle axial loads or forces that are parallel to the axis of the shaft, making them unsuitable for situations where only radial support is needed. Needle bearings, while also capable of supporting radial loads, are a type of roller bearing that includes small, cylindrical rollers. Although they can reduce friction in certain applications, they are still designed for more than just simple radial load support. Ball bearings can support both radial and axial loads but are also not limited solely to radial applications, therefore not aligning with the specific requirement of supporting only radial loads. The design and functionality of each type of bearing highlight the journal bearing's unique capability for purely radial load support.