Which of the following lists the three types of plain bearings used in industry today?

• A. Journal Bearings, Thrust Bearing, and Linear Bearing
• B. Ball Bearings, Roller Bearings, and Needle Bearings
• C. Journal Bearing, Ball Bearing, and Linear Bearing
• D. Thrust Bearing, Linear Bearing, and Ball Bearing

Answer: (A)

Plain bearings are bearings that rely on sliding contact between surfaces rather than rolling elements. In industry, they’re typically categorized by how the load is carried and how motion is guided: radial support around a shaft (journal bearings), axial support along the shaft direction (thrust bearings), and guides for straight-line motion (linear bearings). The three that fit this sliding-contact, non-rolling category are journal bearings, which support radial loads on rotating shafts; thrust bearings, which take the axial load between bearing faces; and linear bearings, which provide sliding support for straight-line movement in a guide system. The other options mix in rolling-element bearings like balls and rollers, which are not plain bearings, so they don’t belong in the same category.