Gearing Principles

Question 1

Pitch line

Answer 1

The line dividing the gear tooth lengthwise

Question 2

Gear tooth face

Answer 2

Upper portion of tooth

Question 3

Gear tooth flank

Answer 3

Lower portion of tooth

Question 4

Gear tooth toe

Answer 4

Smaller end of tooth

Question 5

Gear tooth heel

Answer 5

Larger end of tooth

Question 6

Gear tooth drive side

Answer 6

The convex side of tooth, push is against drive side

Question 7

What it purpose of gear tooth root fillet

Answer 7

Give tooth strength and reduce the chances of cracking at tooth base

Question 8

Gear tooth pitch circle

Answer 8

Diameter of gear when measured across pitch line

Question 9

Gear tooth clearance

Answer 9

Space between the tip of one tooth and the root of the meshing teeth, helps to maintain a lubrication film.

Question 10

Backlash

Answer 10

The space between to gear teeth in mesh

Question 11

Non-hunting gear

Answer 11

Pinion teeth number divides equally into the number of teeth on the crown gear. Must be timed

Question 12

Partial non-hunting

Answer 12

2 or 3 revolutions of crown must occur before back to starting point. Ratio will divide unequally completing in 1 or 2 decimals. Must be timed

Question 13

Hunting design

Answer 13

Not timed. Every pinion tooth will touch every crown tooth.

Question 14

Gear reduction

Answer 14

When a small gear drives a large gear. Speed will be decreased and torque will be increased.

Question 15

Gear overdrive

Answer 15

When large gear drives a small gear. Speed will increase and torque will decrease

Question 16

Straight cut spur gear

Answer 16

Tooth appears symmetrical, generate not end thrust. Cheap to manufacture, but are not as strong

Question 17

Internal gears

Answer 17

Have teeth located on the inner perimeter of the gear. Can have a high load handling capability

Question 18

Single helical gears

Answer 18

Teeth cut at angle to the shaft. Provides great strength and less noise. Angled meshing contact ensures that multiple teeth are involved in the transmission of torque. Create axial thrust loads.

Question 19

Herringbone gears

Answer 19

Double helical gears. 2 helical gears attached together so that the axial thrust loads cancel each other out.

Question 20

Hypoid gears

Answer 20

Centerline of the drive pinion shaft is below the centre of the crown gear. Has even more tooth contact then spiral bevel gear sets, increasing load handling capabilities.

Question 21

Amboid gears

Answer 21

Centerline of the drive pinion shaft is above the centre of the crown gear. A before H = A above H

Question 22

Reactionary member

Answer 22

The member of a planetary gear that is held stationary?

Question 23

What are the 3 main gear components of the simple planetary gear set?

Answer 23

Sun gear
Ring gear / Internal gear
Planet pinions on carrier

Question 24

Why do some angle gear sets need to be timed?

Answer 24

The gears are designed and lapped into a distinctive wear pattern from the factory, and need to maintain this relationship