Chapter 3 Unit 4 Flashcards
(21 cards)
What are gears?
Wheels with cogs or spurs round the edge
What do you call it when two or more gears interlink?
Mesh
What are shafts?
Axels that the gears are mounted on
What shape are the cogs normally?
Shaped like a wedge
What is the difference between the driver gear and the driven gear?
Driver gear is the one that starts the rotation- Input motion
Driven gear rotates when the driver gear starts rotating- output motion
Which way does a pair of gears always turn?
Counter rotate
Why do gears turn counter clockwise?
Driver gear turns clockwise hen teeth pushes down in driven gear causing it to turn anti clockwise
What is the function of an idler gear?
Extra gear that Changes the direction of the driven gears rotation
What are some characteristics of an idler gear?
- usually small not to take up space
* wears out quicker - moves fast so hard and strong material
What do gears change?
Velocity ratio and force ratio
How is there an increase in velocity in a hand operated beater?
Whisks turn much faster than the handle is turned to make the job easier increase in velocity because driven gear smaller than the driver gear
What system is used to increase velocity and vise versa
- Driver gear is large and the driven gear is small
* Driver gear is small and the driven gear is large decrease in velocity
What is velocity ratio?
How much velocity has increased or decreased determined by the number of teeth on driver and driven gears
When is the velocity ratio greater then one?
Driven gear has fewer teeth than the driver gear
How do you calculate the velocity ratio of the driven gear has 12 teeth and the driver gear has 24 teeth?
24 divided by 12=2
How do you calculate the velocity ratio of the driven gear 24 teeth and the driver gear has 12 teeth ?
12 divided by 24= 0,5 or half
When is the velocity ratio less than one?
Driven gear has more tasty than the driver gear
When will the force ratio be bigger than one?
When the driven gear has more teeth than the driver gear - driven gear has more turning force
When will the force ratio be smaller than one?
Driven gear has fewer teeth than the driver gear - driven gear has less turning force
When the force ratio is greater than one what will the velocity ratio be? Vise versa
Smaller than one
Force ratio is smaller than one the velocity ratio will be greater than one
Read through the cyclist thing
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