Gearing Priciples 303a Flashcards
What is the dividing line of a tooth called?
Pinch line
What is the upper portion of the pinch line called?
Face
What is the bottom half of the pinch line called?
Flank
When one end of the tooth is larger than the other what is each end called?
Big end called heal
Smaller end called toe
What does the centre line of a gear tooth tell you?
Splitting the tooth Halfway vertically
The convex side of a gear tooth is usually the what?
Drive side
The concave side of a gear tooth is usually the what side?
Coast
What is the root fillet of a gear?
Flat portion between teeth in the valley
What are the pitch circles of a gear?
Root = bottom of gear teeth
Pitch = when the gears start to taper
Outside = tips of gear teeth
What is the purpose of backlash?
For gear tooth expansion and lubrication
What is non hunting?
The same teeth contact the same spots of the driven and drive member. Needs to be timed upon installation
3:1
What is partial hunting?
The teeth need to make a few revolutions to return to its original tooth on the driven and drive member. Timing is needed upon install
4.50:1
What is a hunting gear set?
The same tooth never contacts the same driven and drive member in any order. Doesn’t require timing
3.333:1
What is direct drive?
When the driven and drive gear are the same size
1:1
What is a reduction/underdrive?
When the driven gear is bigger than the drive. Speed is reduced but torque increases
2:1
What is overdrive?
The driven gear is smaller than the drive gear. Causing a increase in speed but a reduction in torque.
0.5:1
What changed the direction of a driven gear?
An idler is used to change the direction of a gear
Do idlers affect overall value of a gear set?
No
3 types of gear cuts?
Straight spur cut
Helical cut
Double helical or herringbone
What must be used in a helical gear set?
Thrust washers to combat axial side loads
Are angle drives only 90 degrees?
No they can be less than 90 as well
What is an advantage of spiral gears?
Stronger and quieter
What is hypoid angle gears?
The pinion drive is below the centre line of the driven gear
What is amboid gears ?
The drive gear is above the centre line of the driven gear
What are advantages of worm and wheel gear?
Very strong
Huge torque multiplier
What are the components of a simple planetary gear set?
Sun gear
Planet pinion gears
Internal ring gear
In a planetary what is the held member sometimes referred to as?
Reactionary member
What are some planetary gear set conditions?
Direct drive- any two members locked together
Reverse- carrier held
Reduction- carrier driven
Overdrive- carrier drive
Neutral- nonmembers held
