MDE Unit 4 Q3

A thrust bearing is a type of rotary bearing designed to support axial loads. This means it can handle forces that push or pull along the axis of a shaft, rather than forces perpendicular to it.  

1. Thrust Ball Bearings – Everything you need to know

2. Radial and thrust forces in bearings – SMB Bearings

How it works:

• The bearing consists of a series of rolling elements (balls or rollers) that distribute the load across a larger area.   1. Thrust bearing – Wikipedia en.wikipedia.org
• These rolling elements are typically contained between two hardened steel plates.
• As the shaft rotates, the rolling elements distribute the axial load evenly, minimizing friction and wear.   1. Thrust Bearings – An Overview – Tameson.com tameson.com

Common applications:

• Automotive transmissions
• Marine propulsion systems
• Turbines
• Pumps
• Compressors

Would you like to know more about the different types of thrust bearings or their specific applications in marine engines?

Opens in a new windowen.wikipedia.org

thrust bearing

Thrust bearings are essential components in large medium-speed diesel engine turbochargers to counteract the axial forces generated during operation.

Reasons for Thrust Bearings:

1. High Boost Pressure: Turbochargers generate significant boost pressure to force more air into the engine’s combustion chambers. This pressure exerts an axial force on the turbocharger shaft, tending to push it in one direction.   1. Turbocharger – Wikipedia en.wikipedia.org
2. Rotor Dynamics: The high rotational speeds of the turbocharger rotor induce axial forces due to imbalances and asymmetries.
3. Shaft Deflection: Under heavy load conditions, the turbocharger shaft may experience slight deflection, resulting in axial forces.

Functions of the Thrust Bearing:

• Absorbs axial loads: The thrust bearing is designed to withstand and distribute these axial forces, preventing damage to the turbocharger shaft and bearings.   1. What Are Thrust Bearings and How Do They Work? | Blog Posts – Monroe Engineering monroeengineering.com
• Maintains shaft alignment: By preventing excessive axial movement, the thrust bearing helps maintain proper alignment of the turbocharger components.
• Enhances turbocharger life: By reducing axial forces and wear, the thrust bearing contributes to the overall lifespan of the turbocharger.

Without a thrust bearing, the axial forces generated in a turbocharger would cause rapid wear and potential catastrophic failure of the turbocharger and engine.

In a turbocharger, the thrust bearing is typically located at one end of the turbocharger shaft. This position allows it to effectively counteract the axial forces generated by the turbine and compressor wheels.

Specific location within the turbocharger:

• Near the compressor end: This is a common placement as the compressor often generates higher axial forces.
• Near the turbine end: In some designs, the thrust bearing might be located closer to the turbine side to balance the axial loads.

The exact location can vary depending on the specific turbocharger design and manufacturer.

Thrust bearings in turbochargers are typically lubricated by the same engine oil that circulates through the entire engine.  

1. Lubricant Behavior and Factors That Cause Turbocharger Failure – ResearchGate

Lubrication process:

1. Oil supply: The engine’s oil pump delivers pressurized oil to the turbocharger.
2. Oil distribution: Oil is directed to the thrust bearing through oil galleries within the turbocharger housing.
3. Lubrication film: The oil creates a hydrodynamic film between the thrust bearing surfaces, reducing friction and preventing wear.
4. Oil return: The used oil is returned to the engine’s oil sump for recirculation.

It’s crucial to use the correct type and viscosity of oil to ensure proper lubrication of the thrust bearing. The oil must be able to withstand the high temperatures and pressures generated within the turbocharger.

Would you like to know more about the types of thrust bearings used in turbochargers or the signs of thrust bearing failure?