M7.10 & M7.11 Flashcards
What are the four types of springs?
- compression
- extension (tension)
- torsion
- wireform
What force do extension springs take?
Pulling forces
What happens if a spring is subjected to overheating?
It may loose characteristics and need to be replaced
What will corrosion on a spring cause?
The spring will reduce the loads it can carry
How are springs tested?
They get tested on there elasticity and compare it to graphs and figures
What are the types of test a spring can go through?
- static extension (most common)
- load/extension
How does static extension testing work?
The manufacturer will publish exact dimensions the spring needs to be at certain resistances
What are bearings used for?
To support the journals of shafts and axles
What are bearings that accept forces at right-angles to the drilling axis called?
Journal bearings or rollor bearings
What are bearings that accept forces in a longitudinal direction called?
Pivot bearings or axial bearings
Why is bearing play necessary?
To allow space for continuous lubrication
What are the five types of bearings?
- ball
- needle
- tapered roller
- cylindrical roller
- Spherical roller
What does lubrication do in a bearing?
Reduces friction, wear, corrosion
Bearings come with a preservative coating, what is important to remember about this?
You don’t need to clean it off before lubrication because they will be compatible
What will too much lubrication cause in a bearing?
Excessive churning and generate high temperatures
What is false brinelling?
Excessive external vibration
What is true brinelling?
When loads exceed the elastic limit of the ring material
What is fatigue failure (spalling)?
Fracture of the running surfaces and removal of small particles of material
What will contamination of a bearing cause?
Denting of raceways or balls that lead to vibration and wear
What is lubrication failure?
When the lubrication fails which will be followed by catastrophic failure
What is misalignment of a bearing?
When a wear path is created due to the balls not being on the raceway
What is caused due to loose fittings of bearings?
Fretting (fine metal particles which oxidise)
What is caused due to a tight fit of bearings?
A deeper raceway and will increase friction and temperature
What must you remember to do when cleaning bearings?
Do not touch with bare hands
How soon after final rinse should bearings be greased?
Within two hours
