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Millwright 2nd Year > Gears > Flashcards

Flashcards in Gears Deck (54)
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0
Q

Enclosed your drives are contained how

A

Contained in a gearbox with lubrication supply

1
Q

Open gear drives are exposed to what and are suitable for what kind of application

A

Outside environment and are suitable for light duty applications

2
Q

What are gear sets used for

A

To be meshed together in pairs and intended to mate

3
Q

What is gear train

A

Two or more gears that mesh or mate together

4
Q

What is a pinion

A

Two gears with different number of teeth

gear with fewer amount of teeth is the pinion

5
Q

If the smaller gear is the pinion what is the larger gear in a bevel and hypoid mating gear

A

Crown gear

6
Q

What is the drive gear

A

The gear the drives the output gear

7
Q

What is the driven gear

A

Gear that is driven by the drive gear

8
Q

What Kinda drive has the same speed as the input and output

A

Direct drive

9
Q

What does a speed reducer do

A

If you have a fast input speed the output speed will be reduced
Ex
Input will have a small gear going into a big gear on the output

10
Q

Speed increaser

Is the drive gear smaller or bigger

A

Bigger

11
Q

What is an overhung gear

A

Bearing support only on one side of the gear

12
Q

What is a straddle mounted gear

A

A bearing on both sides of the gear

13
Q

Internal gears have teeth on the inside or outside of the gear plank and are they smoother or not as smooth

A

Inside

Smoother

14
Q

Compound gear train has how many shafts and how many gears

A

Three or more shafts and four or more gears

15
Q

Define end play

A

The gear or shaft can move axially

16
Q

Pre-loads have how much axial clearance for proper gear mesh

A

Zero

17
Q

What is the axis of rotation

A

Centerline around which gear or parts revolve

18
Q

What causes gear wear

A

Lack of lubrication, abrasives and bad tooth contact

19
Q

What is a floating gear or shaft

A

Where one gear or shaft is allowed to move axially to its best position kind of like bearing

20
Q

Right and left-hand gears are called what kind of angle

A

Helix angle

21
Q

How can you tell if you have a left or right hand gear

A

Which ever way the gear points away from centerline of the shaft

22
Q

Describe a worm and worm wheel gear set

A

The worm is the smaller gear and looks like a screw the worm wheel is a larger circular gear

23
Q

The clearance between gear teeth and the pitch line is called what

A

Back lash

24
Q

Top half of the gear tooth is called what

A

Addendum

25
Q

Bottom half of the gear tooth including the clearance is called what

A

Dedendum

26
Q

Total depth of the tooth top to bottom including the clearance is called what

A

Whole Depth

27
Q

Working depth includes what minus the clearance

A

Addendum + Dedendum

28
Q

What are the two best pressure angles in degrees

A

20° and 14°

29
Q

If you have a steep and smooth helix angle is this better or worse

A

Better

30
Q

If you have more starts then less starts on a worm gear box will the worm wheel move faster or slower each revolution

A

Faster

example 3 starts equals three pitches each revolution

31
Q

What is the formula to get diametral pitch

A

Number of teeth on your gear divided by pitch diameter

32
Q

List three ways to have proper gear mesh

A

Have the same diametral pitch
same pressure angle
and correct your hand left or right
Same helix angle

33
Q

Can idlers change the speed of the input and output gear

A

No because idlers only change the direction or keep it the same

34
Q

What Kind of gears are suitable for shafts parallel to each other with no axial thrust unless misaligned (cowboy)

A

Spur gears

35
Q

Where will external spur teeth be on a gear plank

A

On the outside

36
Q

Where will the internal spur teeth be on a gear plank

A

On the inside

37
Q

What kind of gear system is on a arbor press

A

Rack and pinion

38
Q

How are single helical gears cut

A

They have the teeth cut at an angle to the shaft of the axis

39
Q

Are helical gears stronger or not stronger then spur gears

A

Stronger because they have more teeth in contact at one time

40
Q

Can helical gears be used on shafts that cross over 90° or other angles

A

Yes but the gears have to be left-hand and right-hand in order to mesh proper

41
Q

What are the most common angles for helical gears

A

7° to 23°

most industrial gears have a 20° pressure angle

42
Q

What kind of loads and speed applications are herringbone gears used for

A

High speeds and heavy loads

43
Q

What kind of gear is similar to a doublecut helical gear

A

The herringbone gears

44
Q

For bevel gears what is the most common intersection angle

A

90°

but some intersect at other angles

45
Q

Give four types of bevel gears

A

Miter
straight
spiral
and zerol

46
Q

On gears where the shafts must intersect at 90° are called what kind of bevel gear

A

Mitre gear

47
Q

Worm bleed refers to the distance by which what

A

One tooth on the worm advances in one turn this is determined by the number of starts on the worm

48
Q

Parallel
angle
compound
and planetary gear systems are all what kind of drives

A

Fixed speed gearbox drives

49
Q

What kind of specific combination of gears can produce several speed and torque combinations from one set of gears in a small space
Ex: Sun gear, carrier with planet gears mounted to it and a ring gear

A

Planetary gear systems

50
Q

What kind of methods do you use to check for acceptable mesh patterns while being reassembled

A

Prussian blue
Venetian red
Black light
pencil lead

51
Q

What is a good practice before using Prussian blue on your gear teeth to measure mesh patterns

A

Clean both gears very thoroughly

52
Q

What is the best tool to use to measure backlash

A

Dial indicator

53
Q

Tie rod torque arms should be mounted in a position that forms what kind of angle

A

A 90° angle