Gearing Principles

Question 1

Gear teeth may be parallel to one another or they may be tapered, with one large end and one smaller end.
True
False

Answer 1

True

Question 2

The gear pitch line is used to divide the following gear tooth areas:

a. heel and toe.
b. drive and coast.
c. face and flank.
d. fillet and profile.

Answer 2

c. face and flank.

Question 3

Explain why some angle drive gear sets may need to be timed.

Answer 3

The manufacturer may design the gear set in such a manner that a very distinctive wear pattern will exist between the mating gear teeth during operation. The gears have been lapped in this pattern and need to be timed to continue this specific relationship.

Question 4

If a simple gear set has a gear ratio of 4:1. Explain which member is turning at 4 revolutions.

Answer 4

Drive or input member is rotating at 4 revolutions.

Question 5

When installed between a drive and driven gear, an idler gear affects speed and torque changes between the two gears.
True
False

Answer 5

False

Question 6

Name and explain the tooth design use on two types of external gears.

Answer 6

a. straight cut spur gear- Teeth cut inline with the mounting shaft.
b. Helical gear- Teeth cut at an angle to the mounting shaft.
c. Double helical gear. Two sets of teeth. each cut at an opposite angle to the mounting shaft.

Question 7

What is another name for a double helical gear?

Answer 7

Herringbone gear

Question 8

Identify the three main components of a simple planetary gear set.

Answer 8

a. internal gear (ring gear)
b. planet pinion gears and planet carrier assembly
c. sun gear

Question 9

A gear tooth can be sub-divided into four distinctive quadrants. Identify the names of each of those quadrants.

Answer 9

a. face
b. flank
c. heel
d. toe

Question 10

When two gears are in mesh, a gap is formed between the tip of one gear tooth and the root in the opposite gear. The gap is called the:

a. fillet.
b. profile
c. backlash
d. clearance

Answer 10

d. clearance

Question 11

Gears may operate together as direct drive assemblies. Identify two other types of gear configurations and explain the type of speed and torque changes that would be expected between the input and output members.

Answer 11

a. Reduction. Speed reduction, torque increase.

b. Overdrive. Speed increase, torque reduction.

Question 12

Which of the following gear ratios would be a reduction gear ratio?

a. 0.10:1
b. 1.00:1
c. 10.00:1
d. 1.00:2

Answer 12

c. 10.00:1

Question 13

Explain the purpose of an idler gear.

Answer 13

An idler gear is used to change the direction of rotation of the driven gear to the same direction of rotation as the drive gear. This could make reverse gear possible.

Question 14

Identify one common gear set where internal gears may be used.

Answer 14

Planetary gear sets.

Question 15

Identify the three main components of a simple planetary gear set.

Answer 15

a. Internal gear (ring gear)
b. planet pinion gears and planet carrier assembly
c. sun gear