Bearings And Transmissions Flashcards
In which direction do axial bearings accept loads?
Longitudinal (sideways)
What problems may occur if bearings are over-greased?
Cause excess churning and generate extremely high temperatures
What are the three functions of lubrication?
Provides a film to separate the moving parts
Carries away heat
Protects from corrosion
Five basic types of anti-friction bearings?
Ball Needle Tapered Cylindrical Spherical
What loads can ball bearings take?
Light radial loads
What loads can needle bearings take?
High radial loads and very light axial loads
What loads can tapered bearings take?
Axial and radial loads
What loads can cylindrical bearings take?
Heavy radial loads and minor axial loads
What loads can spherical bearings take?
High radial load
What may happen if angular contact bearings are subjected to reverse loading?
Excessive stress
Increased temperature and vibration
How does overheating affect bearings? How can it be detected?
Loss in hardness causing early failure
Ball and ring deformation
Destroy lubrication
Detected by discolouration of rings, balls, and cages
What are the causes of misalignment?
Bent shafts
Burrs or dirt on shaft
Shaft threads or locking nuts not aligned
Five bearing defects?
Contamination Lubrication Corrosion Misalignment Loose
What is backlash?
The play between mating tooth surfaces at the tightest point of mesh
What is a worm gear?
Special gears that resemble screws and can be used to drive spur gears or helical gears
Most commonly used gear type?
Spur
Where are bevel gears used?
To transfer power between intersecting shafts
Where may a chain be used instead of a cable?
Where considerable force is exerted
How are the dimensions of a chain classified?
Pitch
Where are chains normally used
Control column installations
Aileron and elevator controls
Trim control systems
What are bi-planer blocks?
Changing the directional plane of the chain
What could be a fault if a chain can be pulled away from the sprocket?
Wear
Tension
How are chains checked for elongation?
Cleaned
Placed on a flat surface
Stretched under load and checked against original dimensions
If over 2%, chain discarded
Where are chains disconnected?
At design breakdown points
How are screwjacks checked for backlash?
Clamp checking tool onto screwshaft adjacent to front of jack body
Position dial indicator rod to contact face of ball nut
Manually apply force to slat in retract direction and record reading on indicator
Allow slat to fully extend and record reading
Difference should not exceed 0.030”
Repeat three times
If backlash is excessive, replace screwjack
How is a chain checked for articulation?
Moving it over a screwdriver at 180 degrees
