Gearing Priciples 303a

Question 1

What is the dividing line of a tooth called?

Answer 1

Pinch line

Question 2

What is the upper portion of the pinch line called?

Answer 2

Face

Question 3

What is the bottom half of the pinch line called?

Answer 3

Flank

Question 4

When one end of the tooth is larger than the other what is each end called?

Answer 4

Big end called heal

Smaller end called toe

Question 5

What does the centre line of a gear tooth tell you?

Answer 5

Splitting the tooth Halfway vertically

Question 6

The convex side of a gear tooth is usually the what?

Answer 6

Drive side

Question 7

The concave side of a gear tooth is usually the what side?

Answer 7

Coast

Question 8

What is the root fillet of a gear?

Answer 8

Flat portion between teeth in the valley

Question 9

What are the pitch circles of a gear?

Answer 9

Root = bottom of gear teeth

Pitch = when the gears start to taper

Outside = tips of gear teeth

Question 10

What is the purpose of backlash?

Answer 10

For gear tooth expansion and lubrication

Question 11

What is non hunting?

Answer 11

The same teeth contact the same spots of the driven and drive member. Needs to be timed upon installation

3:1

Question 12

What is partial hunting?

Answer 12

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

Question 13

What is a hunting gear set?

Answer 13

The same tooth never contacts the same driven and drive member in any order. Doesn’t require timing

3.333:1

Question 14

What is direct drive?

Answer 14

When the driven and drive gear are the same size

1:1

Question 15

What is a reduction/underdrive?

Answer 15

When the driven gear is bigger than the drive. Speed is reduced but torque increases

2:1

Question 16

What is overdrive?

Answer 16

The driven gear is smaller than the drive gear. Causing a increase in speed but a reduction in torque.

0.5:1

Question 17

What changed the direction of a driven gear?

Answer 17

An idler is used to change the direction of a gear

Question 18

Do idlers affect overall value of a gear set?

Answer 18

No

Question 19

3 types of gear cuts?

Answer 19

Straight spur cut

Helical cut

Double helical or herringbone

Question 20

What must be used in a helical gear set?

Answer 20

Thrust washers to combat axial side loads

Question 21

Are angle drives only 90 degrees?

Answer 21

No they can be less than 90 as well

Question 22

What is an advantage of spiral gears?

Answer 22

Stronger and quieter

Question 23

What is hypoid angle gears?

Answer 23

The pinion drive is below the centre line of the driven gear

Question 24

What is amboid gears ?

Answer 24

The drive gear is above the centre line of the driven gear

Question 25

What are advantages of worm and wheel gear?

Answer 25

Very strong

Huge torque multiplier

Question 26

What are the components of a simple planetary gear set?

Answer 26

Sun gear

Planet pinion gears

Internal ring gear

Question 27

In a planetary what is the held member sometimes referred to as?

Answer 27

Reactionary member

Question 28

What are some planetary gear set conditions?

Answer 28

Direct drive- any two members locked together

Reverse- carrier held

Reduction- carrier driven

Overdrive- carrier drive

Neutral- nonmembers held