Slide Bearings: Types and Applications
Slide bearings, also known as sliding bearings, are essential mechanical components that support loads, position and guide moving parts, reduce friction and dampen vibration. They are found in a variety of applications and come in different forms, including plain bearings, composite bearings, dry sliding bearings and load-bearing metallic slip surfaces. Each of these sliding bearings specializes in providing support, direction and friction control in varying degrees under conditions including ambient temperatures, high temperatures and contamination.
Plain bearings, also referred to as plane bearings, are commonly composed of a softer, non-metallic material, such as bronze, brass, plastic or composite of plastic and graphite layers. Depending on their unique application, plain bearings can be custom-made products, such as split or caged sleeves, or they can be pre-manufactured and stocked items, such as self-aligning bushings, spherical bushings and flange bushings. Plain bearings have no rolling elements, and rely on a thicker solid lubricant film to reduce the coefficient of friction and the wear and tear of their sliding surfaces. The most commonly used plain bearing is a sleeve bearing, which lies between two components and acts as a permanent cushion to position, guide and support weight loads.
Composite bearings are constructed using metallic and non-metallic materials. The non-metallic materials, such as polysulfone and polypropylene, are employed to reduce friction while the metallic materials, such as steel and bronze, are employed to provide load support. These bearings are designed to combat the wear and tear that is caused by high speed oscillations and vibrations in various applications.
The use of dry sliding bearings is called for in applications where lubrication of components is either not feasible or dangerous. These types of bearings are composed of materials, such as bronze alloy, polytetrafluoroethylene and solid lubricants, that have low friction coefficient. Dry sliding bearings are typically installed between two components where continuous relative movement will take place, allowing for lubrication-independent operations with reduced friction, wear and noise.
The load-bearing metallic slip surfaces are also known as self-lubricating bearing and they require no external lubrication. Because they are constructed by metallurgically bonding a softer bearing material to a harder backing material, the so-called sliding bearing functions as an all-metal bearing at the surface and, as a result, can tolerate exposure to chemicals, such as water and oil, without being damaged.
Sliding bearings are found in a variety of industries and applications, including agricultural machinery, automotive industry, manufacturing machinery, HVAC systems, home appliances and more. In order to properly select and use the sliding bearing best suited for the specific application, it is important to consider the operating environment, including speed, temperature, the level of contamination present, the tolerance for noise, the need for maintenance and the type of movement used. Regardless of their type and application, choosing the correct sliding bearing can prevent the occurrence of costly maintenance or even expensive equipment damage.
