M6.9 Gear Types And Applications Flashcards
What type of teeth do spur gears have?
Straight teeth
What the main disadvantage of spur gears?
Noisy
How are the shafts different in external spur gears?
They are parallel
What is the advantage of internal spur gears?
Space saving
What are the 2 main advantages of Spur gears - helical cut?
. Quieter
. Greater loads
What is the main advantages of bevel gears?
. Intersecting axis
. Heavy loads
What is a disadvantage of hypoid gears?
Can slide ( require constant pressure )
What are worm gears used in?
Flap/trim tab systems
What is the statement about Rack and pinion gears?
Rotational to linear movement
What is the name of the ratio to do with MA?
Teeth ratio
What is speed ratio opposite to?
MA
What is the idler gear?
Sits between drive and driven gear
What is backlash in gears?
. Clearance between gear teeth
. Allow for expansion
What direction does a drive pulley go?
One direction
What does a friction belt rely on?
Friction and tension
What is a positive drive belt?
. Teeth on belt match grooves on pulley
. Means no slip
What is not needed with flat belts?
Tension as have high friction
What are advantages of V-belts?
. Low cost
. Various sizes
. Pulley grooves
What is a v-ribbed belt?
Combines good factors of flat belt and v-belts
What are the advantages of a synchronous pulley?
. Non slip drive
. Non lubricated
. Long life
. Quiet
. Low maintenance
What do roller chain/sprockets both have?
Positive non slip drive
What’s the benefit of an internal spur gear over a external spur gear
Internal spur gears save space
What’s the negative of helical gears
They’re harder to manufacture
Why are bevel gears used
When a drive needs to be transmitted between different axis
What’s the benefits of hypoid gears
Quiet and smoother
Where are worm gears used in aircraft
Flap or trim systems
What’s the purpose of a rack and pinion gear
Converts rotational movement into linear
Where are planetary gears used
In reduction gearing in aircraft systems
What is backlash
The term used to describe the clearance between the gear teeth and the meshing point
What’s the restrictions regarding flat belts
They can’t carry heavy loads or power due to slippage
What’s the advantages of synchronise belts
They are non slip
Low maintenance requirements
Don’t require lubricant
What type of chain is used on the aircraft regularly and why
Roller chains as leaf chains don’t have s good strength
What’s the advantage of chains over pulleys
Chains provide non Slip
What’s the disadvantage of chains over pulleys
They are heavier more expensive and noisier
