Oilers/Plant Tenders (HHC) Civil Service Practice Exam

What does "thick film" lubrication in heavy duty gears indicate?

1. The lubrication prevents any oil leakage

2. The oil supports the load by hydraulic action

3. The oil has a very low viscosity

4. The lubrication only happens during start-up

The correct answer is: The oil supports the load by hydraulic action

The concept of "thick film" lubrication in heavy-duty gears primarily refers to the formation of a lubricant layer that can effectively support the load through hydraulic action. In thick film lubrication, the lubricating oil creates a substantial film between the contacting surfaces of the gears, allowing for effective load transmission without direct metal-to-metal contact. This hydraulic action occurs as the oil film's thickness increases under load, preventing wear and reducing friction even under high-pressure conditions. This type of lubrication is essential in high-load applications where maintaining a robust film is necessary to protect the components from damage and wear over time. The ability of the lubricant to maintain this film under various operational conditions is crucial in ensuring the longevity and efficiency of the heavy-duty gears. In contrast, other approaches to lubrication, such as boundary lubrication, do not provide the same level of protection and can lead to increased wear and potential failure of the gear system under load. Thus, the correct understanding of thick film lubrication highlights its role in load support via hydraulic action, which is fundamental in heavy-duty mechanical applications.