What Differentiates the Bearing and Bushing?

Bearings and bushings are used in a multitude of applications from complex aerospace machinery to simple clocks. They are a small component, yet there are many different variations because each one supports different loads and performance. So, what exactly are they?

Bearings assist machinery in moving at high speeds while reducing friction, stress, and wear. They are typically used to support rotating shafts in machines. On the other hand, a bushing is an independent plain bearing that supports a shaft; it allows relative motion by sliding instead of rolling. Unlike bearings, bushings don't have multiple components.

Most bearings support a rotating shaft in machinery. They allow movement between components and provide contact between them, such as balls or rollers, which reduce friction. There are two general classifications: journal bearings and thrust bearings. Journal bearings support loads that act at right angles to the axes while thrust bearings support loads that act parallel to the axis. Within these classifications, there are many subcategories, and each is used to support different loads.

Bushings provide low friction motion and reduce power consumption, noise, and wear. They are metal tubes that are typically made from a bronze powder and are self-lubricating. The way that the bronze powder is compressed allows small pores to remain. They are saturated with oil, which seeps into the pores. When the bushing contacts a shaft, it deposits a thin film of lubricating oil. Bushings are often cheaper than ball bearings and can be used on both hardened and non-hardened shafts, while the ball bearing can only be used on hardened shafts. The disadvantages of using a bushing are that they can move in a jerking motion and they may not fit properly, leading to faster wear and tear of the machinery.