Gears

Question 1

What do gears do?

Answer 1

Transmit torque through positive engagement of teeth

Question 2

Advantage of gears?

Answer 2

No slippage

Question 3

What is open gear?

Answer 3

No case or a case taken apart

Question 4

What is closed gearing?

Answer 4

Gearing in a case

Question 5

Five designs of gears?

Answer 5

Spur, helical, bevel, hypoid, worm.

Question 6

How do you know it’s a spur gear?

Answer 6

Straight cut teeth. Moderate speeds

Question 7

Disadvantage of spur gears?

Answer 7

Noisy and high wear at high speed.
No shock or vibration.

Question 8

Advantage of spur gear?

Answer 8

No thrust loading
Low cost
Low maintenance

Question 9

With no idler and with idler what way do two spur gears turn?

Answer 9

No idler - opposite
Idler - same

Question 10

How to find ratio of two gears?

Answer 10

Big gear / small gear

Question 11

What is the smaller gear called?

Answer 11

Pinion

Question 12

Advantage of helical gars?

Answer 12

More load, smoother quieter operation, less vibration and higher speeds

Question 13

Disadvantage of helical gears?

Answer 13

Have to have thrust load bearings.

Question 14

Advantage of double helical gears?

Answer 14

No thrust loading.
Good for shock and vibration.
Smooth operation.
Hugh speed and ratio in single stage.

Question 15

Advantage of herringbone gears?

Answer 15

Good for shock and vibration.
High single reduction.
More torque less speed then double helical gears.

Question 16

When do you use internal gears?

Answer 16

Where space is an issue.

Question 17

What direction do internal gears rotate?

Answer 17

Same direction unless has an intermediate gear then opposite direction.

Question 18

Parts of planetary system gears?

Answer 18

Pinion - suns gear
Idler - planet gear
Ring - ring gear

Question 19

Advantages of planetary system over internal gears?

Answer 19

More power transfer

Question 20

What does a gear rack / rack and pinion do?

Answer 20

Convert rotational motion into linear motion.

Question 21

What is cross axis helical gear used for?

Answer 21

Transmit power at different angles 90 degrees on shaft

Light to moderate load

Question 22

What are worm gears used for?

Answer 22

Transmit power on a right angle on non intersecting shafts

Question 23

Advantage of worm gear?

Answer 23

High speed-reduction ratios in a limited space

Shock loads

Quite

Constant output speed free of pulsations

Question 24

Disadvantage of worm gear?

Answer 24

Lower efficiency then other gear types
Produce a thrust load need bearings

Question 25

Three types of worm gears?

Answer 25

Cylindrical (lowest torque) (low load)
Single envelope (medium)
Double envelope (most torque) (high load)

Question 26

Disadvantage of bevel gears?

Answer 26

Thrust loads on both shafts

Question 27

Four types of bevel gears?

Answer 27

Straight, zerol, spiral, skew.