190303A Flashcards
What divides a gear tooth lengthwise?
Pitch line
What is the larger end of a gear tooth called?
Heel
What is done to a root fillet to increase strength?
The fillet is slightly rounded
When describing Path-of-Power where is power coming from and traveling too?
From the engine flywheel to the drive axles
When an engine is not delivering power what side of the gear tooth is being used?
Coast side or Concave side
What are three diameters of a pitch circle that can be measured?
Root, Pitch and Outside circle
Which circle is used to determine circular gear pitch?
Pitch Circle
Why is it important for gears to have the same circular gear pitch?
With the same circular gear pitch the gears relationship is strong and the most force can be transmitted through the gears.
What is done to the outside surface of a gear?
Hardened
True or false: Clearance provides space for lubrication between teeth?
True
True or false: Gear teeth should always be in tight contact
False: backlash is needed to allow room for expansion
What tool is usually used to measure backlash?
Dial indicator
What should you be aware of when changing backlash?
The wear that occurs on gear teeth
When two gears are in mesh what is the smallest gear referred as?
Pinion Gear
The crown gear is also know as?
The ring gear
True or False: All gear sets must be timed?
False: only non-hunting and partial non-hunting gear sets must be timed.
Are wear patterns are always the same on gear sets?
No. non-hunting, hunting and partial non-hunting gear sets will have different wear patters,
How many revolutions does it take for pinion gears to return to the original spot on a partial non-hunting set?
More than one full revolution.
What is unique about a hunting gear set ration?
there will be multiple decimal points.
ie. 3.44444:1
What changes in speed and torque when a direct drive occurs?
The output speed and torque will be the exact same as the input speed and torque
What is the formula to find a gear ratio?
driven teeth divided by drive teeth
What is a reduction also known as?
Underdrive
Does the input make more or less revolutions than the output gear during a reduction?
The input (Drive) gear will have to make more revolutions than the output (driven) gear.
What decreases during a reduction?
Output Speed
How can you create more torque on an output gear?
Reduction/Overdrive
If input is driving at 1000RPM, in a 2:1 reduction. How fast is the output being driven?
500RPM
Two external gears turn which direction in relation to eachother?
The girls will turn in opposite directions
Is the drive gear larger or smaller than the driven gear in a overdrive situation?
The drive gear will be larger
True or False: In an overdrive situation, output speed will decrease and output torque will increase
False. In an overdrive output speed increases while torque decreases
How can you change direction on a driven gear without changing the input direction?
By adding an idler
Do idlers change speed and torque outputs in basic gear sets?
No idlers only change direction
What type of thrust(s) are created when two spur gears are in mesh?
Radial thrust, the gears are trying to push eachother apart
Is axial or radial thrust created by helical cut gears?
Axial thrust is created
What can be used to offset axial thrust loads?
Thrust washers or bearings
Also a second helical cut gear can be used
Why are straight cut gears used more in off-road applications than on-road applications?
Straight cut gears are larger to be strong. Larger gears are heavier, so they will have less affect on the performance of large off-road equipment
External gears have teeth facing the inside of the gear?
No, external gears have teeth facing out
Internal gears are a weaker gear?
No, internal gears can be very strong
If an external gear is meshed with a internal gear, with the internal gear turning clockwise. Which way will the external gear travel?
Clockwise also.
Herringbone gears are also known as single helical gears?
No. Herringbone gears are a double helical cut gear
