Lubricants and Their Mechanisms

Lubricant Function

• Lubricants reduce wear and tear by creating a thin film between moving surfaces.
• This film prevents direct contact between the surfaces, reducing friction and heat generation.
• This film also carries away contaminants and heat, further reducing wear.

Thick Film Lubrication

• Thick film lubrication occurs when the lubricant film is thick enough to separate the moving surfaces completely.
• This typically happens at high speeds and loads, where the lubricant is forced into the contact zone by the motion of the surfaces.
• Thick film lubrication is desirable because it provides the best protection against wear.

Oil in a Journal Bearing

• In a journal bearing, the oil forms a wedge-shaped film between the rotating shaft and the bearing.
• The wedge shape is created by the rotation of the shaft, which forces the oil to flow around the bearing.
• This flow generates a pressure that supports the shaft and reduces friction.

Low Coefficient of Friction

• A low coefficient of friction means that less force is required to overcome friction between two surfaces.
• This reduces energy loss and heat generation in lubrication systems.
• It also improves the efficiency and longevity of the machine.

Hydrodynamic Lubrication

• Hydrodynamic lubrication relies on the motion of the surfaces to generate a pressure in the lubricant film.
• This pressure is sufficient to support the load and separate the surfaces.
• This type of lubrication is common in journal bearings and other applications where high speeds and loads are involved.