Sliding Contact Bearing

By Mohit Uniyal|Updated : August 26th, 2022

Let's start with a basic understanding of bearings before diving into the specifics of sliding contact bearing. Bearings are "components that aid in the rotation of objects." They provide support for the rotating shaft within the apparatus. Automobiles, aeroplanes, power generators, and other machines need bearings. Sliding contact bearing can even be found in commonplace household goods like refrigerators, vacuum cleaners, and air conditioners. Bearings help the wheels, gears, turbines, rotors, and other rotating shafts of those devices to rotate more smoothly.

The most straightforward sort of bearing is a sliding contact bearing, which consists solely of a bearing surface with no rolling parts. As a result, the journal (the section of the shaft that makes contact with the bearing) glides across the bearing surface. A shaft revolving in a hole is the most basic example of a plain bearing. A primary linear bearing is a pair of flat surfaces that allow movements, such as a drawer and the slides it rests on or the ways on a lathe's bed. Let's take a deeper look at sliding contact bearing and its benefits and drawbacks.

What is Sliding Contact Bearing?

Journal bearings, sleeve bearings, and plain bearings are all terms for sliding contact bearings. This bearing is typically used for shaft slides that are put over the bush surface and cause friction or wear. The revolving surface has been separated by lubricating fluid to reduce friction.

Sliding Contact Bearing Definition

The sliding in sliding contact bearings occurs along the contact surfaces between the moving and immovable elements. Plain bearings are another name for sliding contact bearings.

A particular metal, such as white or bronze, is also used to create the bush. Sliding bearings are also divided into two varieties, each dependent on the lubrication used in sliding bearings. Hydrodynamic-lubrication bearings and Hydrostatic-lubrication bearings are the two types.

A hydrodynamic bearing is a type of bearing that relies on a thin film of oil to create enough space for the spindle to rotate freely. Journal bearings are the most basic hydrodynamic bearings. Hydrostatic bearings, on the other hand, work on the principle of a sliding surface, in which a pressurized fluid, such as oil or any other type of lubricant, or air, is used to create a gap between two surfaces, allowing both rotating parts to move freely.

Sliding Contact Bearing Diagram

Sliding Contact Bearing Definition

Classification of Sliding Contact Bearing

Slipper or guide bearings are sliding contact bearings in which the sliding movement is guided in a straight path while carrying radial stresses. These bearings are commonly seen in steam engines' cross-heads. Journal or sleeve bearings are sliding contact bearings that slide around the circumference of a circle or along an arc of a circle while carrying radial stresses. Sliding contact bearings are classified into the following categories.

  • Based on the type of load carried
  • Based on the type of lubrication
  • Based on the lubrication mechanism

Bearing Classification Based on Type of Load Carried

According to the direction in which the load is applied, three basic types of loads operate on sliding contact bearings as follows.

  1. Radial bearings
  2. Thrust bearings or axial bearings
  3. Radial – thrust bearings.

Bearing Classification Based on Type of Lubrication

In a shaft bearing combination, the kind of lubrication refers to how much the contacting surfaces are separated. This classification of Sliding Contact Bearing based on type of lubrication contains the following:

  1. Thick film lubrication
  2. Thin-film lubrication
  3. Boundary lubrication

Bearing Classification Based on Lubrication Mechanism

Lubrication is vital to any spinning equipment's efficiency and life expectancy. Lubrication decreases friction, allowing moving machine parts to flow past each other smoothly. There are various types of lubrication mechanisms, as shown in the list below.

  1. Hydrodynamically lubricated bearings
  2. Hydrostatic lubricated bearings
  3. Elastohydrodynamic lubricated bearings
  4. Boundary lubricated bearings
  5. Solid film lubricated bearings

Advantages and Disadvantages of Sliding Contact Bearing

The shaft glides across the bush's surface in this type of bearing, causing wear and friction. A thin film of lubricating oil separates the rotating surfaces to reduce friction. Sliding contact bearings have several advantages and disadvantages compared to rolling contact bearings. which are listed below.

The advantages of Sliding Contact Bearing include:

  1. A simple bearing and housing design.
  2. They are more compact and take up less radial area.
  3. They are less expensive.
  4. The shaft has a simple design.
  5. They are more silent in operation.
  6. They can withstand a lot of shocks.
  7. They are well-suited to operations at medium and high speeds.

The following are the disadvantages of Sliding Contact Bearing:

  1. Frictional power loss is more significant.
  2. They necessitated careful lubrication.
  3. They're usually made to carry solely radial or axial loads.
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FAQs on Sliding Contact Bearing.

  • The sliding contact bearing is a type of bearing where relative sliding motion is seen between the elements in contact. The sliding contact bearings are also known as Journal bearings, sleeve bearings, and plain bearings.

  • Mineral oils and synthetic oils are the most common liquid lubricants used in bearings. Mineral oils are the most widely utilized due to their low cost and stability. Where liquid lubricants can be preserved, they are normally preferable. Grease is a semi-liquid lubricant with a viscosity higher than that of oils.

  • The decreased starting friction of a rolling contact bearing over a sliding bearing is a significant advantage. Rolling contact bearings are known as antifriction bearings because of the reduced friction they provide. Except at very high speeds, little starting and running friction.

  • Ball bearings have a low friction coefficient when rolling, but their load-carrying capability is restricted. Because of the narrow contact area between the balls and the races, this is the case. Apart from radial loads, they can support axial loads in two directions. Oscillatory and rotational motion is controlled by ball bearings.

  • An antifriction bearing uses rolling parts bound by inner and outer rings to absorb the radial forces exerted on the rotor and is usually connected to the shaft using an interference fit. Pumps and aero-derivative gas turbines are commonly fitted with antifriction bearings.

  • Hinges are another sort of specialized mounting, with sliding contact bearing parts between the two sides in most cases. Sliding contact bearings are often utilized in applications with low to moderate speeds. To reduce wear and friction, they require boundary lubrication.



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