7.11 Flashcards
What could testing a bearing at low speeds of rotation highlight ?
Highlight roughness caused from corrosion.
Whats the process of cleaning a bearing ?
Place bearing in solvent bath removing any oil then placed into an ultrasonic bath which shakes off any particles and contaminants still on the bearing.
What does an ultrasonic bath send through bearing which removes particles or contaminants ?
Sends high frequency sound waves which shakes off any contaminants
What must happen to bearings which wont be used straight away after cleaning ?
Coated in rust-preventing oil then wrapped in grease proof paper.
What will to much lubrication or grease cause a bearing to do ?
Run hot
Why would oils be better to use rather than grease when a bearing is rotating at high speeds ?
Grease can heat up at high speeds of rotation.
Can a sealed or shielded bearing be re-greased ?
No. It would have to be replaced if it’s evident that the lubricant has been washed out.
Whats a grease nipple used for ?
Re greasing the bearing.
Whats the 4 types of lubrication used on bearings ?
Hydrodynamic lubrication
Hydrostatic lubrication
Boundary lubrication
Solid film lubrication
Explain hydrodynamic lubrication ?
Thick lubricant
Explain hydrostatic lubrication ?
Air and oil lubricant.
Explain boundary lubrication ?
Thin oil lubricant.
Explain solid film lubrication ?
Paint like coatings mixed with additives and can be sprayed, dipped or brushed onto bearing.
This lubrication repels water.
What is true brinelling caused by and how does it appear ?
Caused by excessive impact and appears as indents in the bearing raceway.
What causes false brinelling and how does it appear ?
Caused by vibrations while static and appears as a wear pattern which looks familiar to brinelling.
