Gears

Question 1

What is the name of the gear that changes rotation.

Answer 1

Bevel gear.

Question 2

What is an advantage of spur gears.

Answer 2

1. They wear out less quickly than other things like pulleys.
2. Positive drive - won’t slip.
3. Low cost of injection moulded gear.

Question 3

What is a disadvantage of spur gears.

Answer 3

1. Only suited to slow speeds due to loud noise at high speed
2. Gear teeth experience a lot of stress
3. Cannot transfer power between non-parallel shafts

Question 4

If the driver is smaller than the driven how fast or slow will the driven be compared to the driver.

Answer 4

The driven will be slower.

Question 5

What is the formula for torque in gears?

Answer 5

T = FxL (N.mm)

Question 6

How do you work out the velocity ratio?

Answer 6

Velocity ratio = Number of teeth on driven gear divided by the Number of teeth on driver gear

OR

Velocity ratio = Input speed divided by the Output speed

Question 7

What is a compound gear?

Answer 7

A compound gear is a number of gears fixed together. Consequently, they rotate at the same speed.

Question 8

What is a gear train?

Answer 8

A gear train is made up of 2 or more gears.

Question 9

What is the idler?

Answer 9

The idler keeps the direction of the driver and the driven the same in a gear train.

Question 10

How do you draw gear diagrams?

Answer 10

2 circles with the outer circle representing the teeth. The outer circles overlap in a gear train.

Question 11

Name 4 types of gears

Answer 11

Bevel
Spur
Worm
Helical

Question 12

What is a helical gear?

Answer 12

gears where the teeth are curved into a helix shape