190303A

Question 1

On a gear tooth, what is the line dividing the tooth lengthwise?

Answer 1

pitch line

Question 2

what is the upper portion of a gear tooth that’s been divided lengthwise?

Answer 2

face

Question 3

what is the lower portion of a gear tooth that’s been divided lengthwise?

Answer 3

flank

Question 4

when a gear tooth has a larger and narrower end, what is the smaller end called?

Answer 4

toe

Question 5

when a gear tooth has a larger and narrower end, what is the larger end called?

Answer 5

heel

Question 6

when describing wider gear sections, what is common regarding the heel and toe sections?

Answer 6

to separate them using a centre section

Question 7

what is tooth profile?

Answer 7

the shape of the tooth

Question 8

what is the root fillet on a gear tooth?

Answer 8

the lowest point between two teeth

Question 9

why is the root fillet area slightly rounded?

Answer 9

gives gear tooth strength and reduce chances of cracking at that area

Question 10

what is a drive side of a tooth?

Answer 10

convex side, the side that gears contact when being driven

Question 11

what is the coast side of a tooth?

Answer 11

the concave side, the side that gears contact when the loaded vehicle is pushing the powertrain

Question 12

what is path of power?

Answer 12

the power flow from engine flywheel to drive axles.

Question 13

what can the path of power be used to determine?

Answer 13

which gears are actually in use and delivering power

Question 14

what pitch circle diameter is the shortest?

Answer 14

the root diameter (root circle)

Question 15

what pitch circle diameter is the greatest?

Answer 15

the outside diameter (outside circle)

Question 16

where is the pitch diameter in relation to the face and flank?

Answer 16

on the centreline that divides the face and flank. (pitch circle)

Question 17

where do teeth mesh at?

Answer 17

the pitch line

Question 18

How do you find circular gear pitch?

Answer 18

find pitch circle, then find the exact centre of each gear tooth

Question 19

what is gear pitch?

Answer 19

the distance between the gear tooth centrelines

Question 20

why must the circular gear tooth pitch be the same on each gear?

Answer 20

provide great gear strength and max force can be delivered through the gears

Question 21

What is clearance?

Answer 21

when gear teeth mesh, a small clearance exists between tip of one tooth and root between 2 teeth on the opposite gear

Question 22

why is clearance needed?

Answer 22

help maintain a lubrication film

Question 23

What is backlash?

Answer 23

clearance on the side of the gear tooth

Question 24

why is backlash needed?

Answer 24

for expansion of gear teeth and lubrication

Question 25

what should you be aware of when measuring or adjusting backlash?

Answer 25

changes in gear tooth profile as the gears wear during operation

Question 26

how can you measure gear tooth backlash?

Answer 26

with a dial indicator

Question 27

Why would you time a gear set?

Answer 27

to ensure they always operate in a specific relationship with one another. creates a specific wear pattern. gears have been lapped in their pattern and need to operate in that specific pattern

Question 28

what is an example of a timed gear set from the book?

Answer 28

engine crank and cam

Question 29

are gear teeth timed in an angle drive gear set?

Answer 29

yes

Question 30

on an angle drive gear set, what is the smaller gear and larger gear called?

Answer 30

smaller: pinion larger: crown

Question 31

What are non-hunting gears?

Answer 31

gear set that develops a specific tooth contact wear pattern. will always contact the same tooth every revolution

Question 32

do non-hunting gear sets need to be timed?

Answer 32

yes

Question 33

How will the number of pinion teeth divide into the number of crown gear teeth on a non-hunting gear set?

Answer 33

equally, ex. 3:1, 5:1. ratio expressed as a whole number

Question 34

What are partial non-hunting gears?

Answer 34

gear set that develops a unique wear pattern. will contact the same few teeth, but in 2-3 revolutions of the crown gear before the first pinion tooth returns to original point

Question 35

do partial non-hunting gears need to be timed?

Answer 35

yes

Question 36

how will the number of pinion teeth divide into the number of crown teeth on a partial non-hunting gear set?

Answer 36

of pinion teeth divides into crown teeth unequally, completes in one or 2 decimal places. ex: 4.45:1, 2.50:1

Question 37

What are hunting gears?

Answer 37

no special wear pattern, every pinion tooth comes into mesh with every crown tooth at some point in operation

Question 38

does a hunting gear set need to be timed?

Answer 38

no

Question 39

how will the pinion teeth divide into the crown teeth on a hunting gear set?

Answer 39

pinion teeth divides into the crown teeth unequally, in a weird continuous number. ex: 3.333:1

Question 40

what is direct drive?

Answer 40

when 2 gears in identical size are in mesh with one another. no speed/torque change. input= output

Question 41

what ratio is direct drive?

Answer 41

1:1

Question 42

How do you calculate gear ratio?

Answer 42

driven over drive

Question 43

what is reduction?

Answer 43

when a smaller gear drives a bigger gear. output speed=1/2 input speed. low speed, high torque.

Question 44

in gear ratios, how is a reduction usually seen?

Answer 44

reduction is always greater than 1. ex: 2:1, 3:1, 4:1

Question 45

What is overdrive?

Answer 45

input gear is bigger than output gear. low torque, high speed. output speed= 2x input speed

Question 46

where are overdrive gear sets often found?

Answer 46

in on highway vehicles to reduce input gear speed while keeping output gear speed

Question 47

in gear ratios, how is overdrive usually seen?

Answer 47

less than 1. ex: 0.5:1, 0.25:1, 0.99:1

Question 48

how can you change direction of rotation?

Answer 48

with an idler gear

Question 49

is an idler gear involved in ratio calculations?

Answer 49

no, only input and output

Question 50

what is one objective when adjusting gear mesh?

Answer 50

achieve a wear pattern that will provide maximum gear set service life

Question 51

what conditions could two gears on two different parallel shafts but in mesh with each other operate?

Answer 51

direct drive, reduction, overdrive.

Question 52

how could you create a reverse gear with 2 gears on 2 parallel shafts?

Answer 52

install a third shaft with an idler between the two gears

Question 53

characteristics of straight cut spur gears?

Answer 53

most basic, tooth identical on all sides, cheap

Question 54

where do straight cut gears contact?

Answer 54

across the entire pitch line

Question 55

where are the main power transmission loads exerted on straight cut gears?

Answer 55

on the two meshing teeth at any one time

Question 56

what is a benefit of using straight cut gears?

Answer 56

no axial thrust loadsw

Question 57

what are disadvantages of straight cut gears?

Answer 57

not high strength, noisyw

Question 58

where can straight cut gears be found?

Answer 58

in transmissions as main gears, or PTO's

Question 59

can internal gears mesh with other internal gears?

Answer 59

fuck no

Question 60

what is needed to transmit power when using an internal gear?

Answer 60

an external gear in mesh

Question 61

benefits of internal gears?

Answer 61

high load handling

Question 62

what are single helical gears?

Answer 62

gears that are cut at an angle to the shaft

Question 63

benefits of helical gears?

Answer 63

good strength and less noise.

Question 64

what lengthens the time it takes for single helical gears to fully mesh?

Answer 64

the leading and trailing edges. ensures multiple teeth are involved in transmitting power

Question 65

what is a disadvantage of single helical gears?

Answer 65

axial thrust loads. use thrust washers

Question 66

what direction are axial thrust loads against a single helical gear?

Answer 66

both directions

Question 67

where are single helical gears common?

Answer 67

transmissions or anywhere that you can control axial thrust loads

Question 68

what are double helical gears?

Answer 68

single helical gears but two of them. separated by a line, line helps out with lubricating the gears

Question 69

what is another name for double helical gears according to the book?

Answer 69

herringbone

Question 70

benefits of double helical gears?

Answer 70

handles heavy torque loads, handle thrust loads like a breeze

Question 71

why doesn't the double helical gears have thrust loads?

Answer 71

the double design helps offset the axial thrust loads at opposite ends of the gears.

Question 72

disadvantage of double helical gears?

Answer 72

expensive

Question 73

What are rack and pinion gears?

Answer 73

change rotary motion to linear motion. mostly straight cut spur gears, the rack is like someone cut open a spur gear and laid it flat

Question 74

what are angle drives?

Answer 74

used when needing to make a directional change, up to 90 degrees

Question 75

what are straight cut bevel gears?

Answer 75

may use straight cut gear teeth. can be noisy and only for small load applications. changes direction of power

Question 76

how can you gain strength in the design of angle drive sets?

Answer 76

use spiral gears

Question 77

where does the pinion gear and shaft sit in relation with the crown gear on a spiral bevel gear set?

Answer 77

at the centreline of the crown gear

Question 78

what does the short stub shaft on the pinion gear help with?

Answer 78

keeps pinion and crown in close contact during sudden high-torque shock loads

Question 79

where does pinion sit in relation to centreline of crown gear on a hypoid angle gear set?

Answer 79

centreline of drive pinion and shaft is below centre of crown gear

Question 80

benefit of hypoid angle gears?

Answer 80

good for high torque loads. has more tooth contact during meshing

Question 81

why must you use special extreme pressure EP lubricant with hypoid gear sets?

Answer 81

these gear sets have a lot of sliding contact and pressure when meshing

Question 82

Where doe the pinion sit in relation to the centre of the crown gear in an ambit gear set?

Answer 82

sits above the centreline. allows for higher driveline position (good for off-road clearance)

Question 83

benefit of worm and wheel gear sets?

Answer 83

very strong, good for high torque loads. load will not overrun

Question 84

where are planetary gear sets used?

Answer 84

where input and output shaft must operate on same plane

Question 85

3 components of planetarium?

Answer 85

sun, ring, planets (on a carrier)

Question 86

what is needed for a planetary to operate?

Answer 86

drive, driven, reactionary

Question 87

if no member is held stationary on a planetary, what condition is it in?

Answer 87

neutral

Question 88

if 2 members are held on a planetary, what condition is it in?

Answer 88

direct drive

Question 89

if the carrier is held in a planetary, what condition is it in?

Answer 89

reverse

Question 90

if the carrier is the driven component, what condition is it in?

Answer 90

reduction

Question 91

if the carrier is driving, what condition is it in?

Answer 91

overdrive