Flashcards in Lubrication Fundamentals Deck (105)
What does ASTM stand for?
American Society for Testing and Material
What does STLE stand for?
Society of Tribologists and Lubrication Engineers
What is tribology?
Tribology is the science of the interactions between surfaces moving relative to each other; the fields include the study of friction, wear and lubrication.
What is lubrication?
Control of friction and wear by introduction of a film between moving surfaces in contact.
What is hydrodynamic lubrication?
Lubrication between two surfaces with the development of a full lubricating film.
What is mixed film lubrication?
The transient lubrication regime in which boundary and hydrodynamic lubrication both occur. (i.e some fraction of both)
What is boundary lubrication?
Lubrication between two rubbing surfaces in the absence of a full fluid lubricating film. Boundary lubrication is often accomplished with the use of extreme pressure additives.
What does EHL stand for, and how does it work?
Elasto-Hydrodynamic Lubrication is the lubrication between two surfaces with a full lubricating film under high loads and speed. The mating surfaces deform elastically due to the incompressibility of the lubricant film under the load. This regime occurs in rolling element bearings.
What is the primary function of a lubricant?
The primary function of a lubricant is to control friction and wear.
What are five secondary functions of a lubricant?
1) Transfer Heat
2) Prevent corrosion
3) Scavenge Debris
5) Transfer force / energy
Name three types (physical phases) of lubricant films.
(Also Plastic) also boundary (chemical), hydrodynamic, and elastohydrodynamic
Improper lubrication contributes to approximately ________ percent of machine failures.
Greater than 40
One inch approximately = ________ microns
25 microns approximately = ____________ inch
Convert 0.05% to ppm.
1% = 10000 ppm So x(ppm) = 10000 x (%)
Move decimal 5 places to the right
What does the abbreviation ISO VG mean?
International Standards Organization Viscosity Grade
What is an approximate conversion from cSt at 40°C to SSU at 100°F?
5 x (cSt at 40° C) approximately = SSU at 100° F
What are the units of Kinematic viscosity?
What are the units of Absolute viscosity?
What is VI?
The resistance of an oil's viscosity to change with temperature.
As the temperature of a lubricating oil increases, what effect does this have on the oil’s viscosity and density?
When pressure increases the viscosity of an oil ________ .
Name the five “rights” of lubrication.
1) Right place
2) Right amount
3) Right type
4) Right quality
5) Right time (Frequency)
What is viscosity?
Measurement of a fluid's resistance to flow.
What is friction?
Friction – the resistance to motion of one object over another
List three harmful effects of friction.
3) Power loss and vibration
What is the most common type of wear mechanism?
Abrasive wear is the most common type of wear.
What are asperities?
Asperities are the roughness or harshness of a surface (tiny peaks and valleys on the surface).
Name three types of synthetic oils.
1) PAO (polyalphanolefin)
6) Phosphate ester
What does NLGI mean?
National Lubricating Grease Institute