Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

mod 6 > 6.9 transitions > Flashcards

6.9 transitions Flashcards

1
Q

What are gears used for?

A

Mechanical advantages or to change the direction of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are gears used in conjunction with shafts and bearings?

A

To transmit power and reduce or increase rotational speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a spur gear?

A

They have straight teeth parallel to the shafts axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do spur gears connect?

A

Parallel shafts only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is bad about spur gears?

A

They can be noisy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When two spur gears mesh together, what is the larger gear called?
What is the smaller gear called?

A

The wheel gear
The pinion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When are external spur gears used?

A

When a change of speed is required and the shafts are parallel to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When are internal spur gears used?

A

When a change of speed is required whilst maintaining an overall minimum diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are helical cut spur gears?

A

They connect parallel shafts but have their teeth cut at an angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an advantage of helical cut spur gears?

A

Smoother and carry heavier loads. Also quieter and smoothly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What load do single helical gears transmit?

A

Axial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does single helical gears having more teeth in a mesh do?

A

Provide a larger contact area so transmit more power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are double helical gears?

A

They are two identical gears joined on the same axis with opposite teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What force does double helical gears act in and what needs to be in the receiving end?

A

Axial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What should a double helical gear degree not be larger than?

A

20 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In wheels with herringbone teeth, what happens to the axial forces?

A

They cancel each other out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When are herringbone gears used?

A

For transmission of large forces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are bevel gears?

A

Used between intersecting shafts and can be designed for any angle of intersection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why are bevel gears quieter, smoother and can take heavy loads better than a size equivalent spur gear?

A

They have curved teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are hypoid gears a progression of?

A

Spiral bevel gears

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do hypoid gears differ to spiral bevel gears?

A

The shafts axis are not on the same plane so do not intersect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do hypoid bears suffer from and how is this fixed?

A

Heavy sliding contact so require constant lubrication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Are hypoid bears quitter and smoother than spur gears?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are worm gears?

A

Non intersection shafts not always at right angles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What do worm gears consist of?
A worm screw that drives a worm wheel (similar to a spar gears)
26
What do worm gears offer?
High reductions in simple steps.
27
Why are worm gears inefficient?
Large sliding movement of their teeth
28
What are worm gears good at?
Being driven in both directions
29
What is rack and pinion?
A gear system that is used to transmit motion between a rotating spur gear and linear toothed rack
30
What forces do rack and pinion gears transmit?
Rotational motion into linear motion
31
What are rack and pinion used for?
Leading edge flaps for extension and retraction
32
When is a mechanical advantage not gained?
If the drive and driven gear have the same number of teeth
33
What is the direction of the shaft and the rotation of the neighbouring gear?
Opposite
34
What is the gear ratio?
Number of teeth on A Number of teeth on B
35
What are idler gears also known as?
Intermediate gears
36
What is one thing an idler gear is used forr?
To make the output gear move in the same direction as the input gear
37
What is another thing an idler gear can be used for
To link gears where there is a gap between them
38
Does the presence of an idler gear make a difference to the ratio of speed?
No
39
For even numbers of gears from the input gear, what is the rotation? For odd numbers of gears?
Opposite the first gear The same
40
How is the direction of rotation calculated?
By counting the number of gears because the driven gear and the gear
41
What must engines operate at for high efficiency?
High speeds
42
High speeds
An arrangement by which an input speed can be lowered to obtain a slower output speed with the same torque
43
What does a reduction gear assembly consist of?
A set of rotating gears connected to a shaft
44
What is the reduction gear assembly known as?
The reduction gear box
45
What are epicyclic and planetary gears used for?
Reduction gearing in aircraft engines
46
whatan does a epicyclic gear consist of?
Two mounted gears so that the centre of one gear revolves around the centre of the other (planets around the sun)
47
What is the meshing and pattern of a gear determined by?
How the teeth mate
48
What can happen if the gears are meshed too high?
The load is transmitted to the smallest portion of the tooth breaking the teeth
49
Where is the ideal placement of teeth?
The middle
50
What can happen if the teeth are too low?
They will not lubricate
51
What can the pattern and meshing be?
Adjusted for direction
52
What is gear backlash?
The gap between the gear teeth and the meshing point to allow for lubrication and prevent overheating
53
What can gear backlash cause?
Lost motion (deviation) making it difficult to achieve accurate positioning
54
What is an indication of worn gearing?
Excessive backlash
55
What is a belt?
Used to link or drive two or more rotating shafts
56
When are belts often used?
In parallel and offer high speed power transmission that is resistant to slipping and misalignment
57
How can belts be used?
Can be driven in one direction Can be crossed so that they work in reverse
58
Why else can a belt be used?
To change the speed of rotation, either up or down
59
What are two types of belts?
Friction and positive drive
60
What are friction drive belts?
They rely on friction between belt and pulley to transmit power. They require tension
61
What are positive drive belts?
Rely on the engagement of the teeth on the belt with grooves on the pulley. There is no slip apart from ratcheting or tooth jumping
62
What are leaf chains?
A simple form of steel chain only consisting of a link plates and pins
63
What is good about leaf chains? Compared to roller chains
They are strong and have high tensile strength compared to roller chains
64
What do leaf chains not have and how does this affect their work?
Roller or bushes meaning they are only to be used for low speed applications and lubricated regularly
65
What is an advantage of chain drives?
The chain cannot slip on the sprocket because of the teeth
66
What is a disadvantage of chain drives?
They are heavy noisy and expensive
67
Where are chain and sprocket gears used?
On areas were slipping must not occur
68
On areas were slipping must not occur
Sheaves and is fitted with a clevis at each end
69
What are roller chains comprised of?
Link plates and pins Rollers and bushes
70
What must the size of the chain link match?
The size and spacing of sprocket teeth
71
What is a sprocket?
A toothed wheel that fits onto a shaft
72
How is a sprocket stooped from rotating on the shaft?
By locking it with by a key way or grub screw
73
How many sprockets do chains connect?
Two
74
Why are sprockets called power transmission chains?
They can transmit motion and force
75
Why are v belts used?
Low cost and ease of installation
76
Low cost and ease of installation
Low cost and ease of installation
77
What is the biggest advantage in the V belt?
The wedging action in the pulley groove
78
What do v ribbed belts consist of? What does the rib ensure?
Fist belts and V belts The belt tracks properly making alignment less critical
79
What is a positive (Synchronous) belt?
The tooth profile is a trapezia design
80
What properties does a synchronous belt have?
A flat belt with evenly spaced teeth perpendicular to the axis of the belt
81
What do timing belts rely on?
Engagement with belt teeth on the sprocket, not friction
82
Where are timing belts used?
Where exact synchronisation between driver and driven shaft is required
83
What is a V belt pulley?
They have a geometry if the grooves located around the pulley to gain traction on a V belt
84
What are V belt pulleys used for?
Transmit power between two parallel axels
85
What do synchronous belt pulleys mate with?
The same pitch as synchronous belts
86
What are the advantages of synchronous belts?
They're quiet, are non slip and non lubricated operation. They have low maintenance requirementsv
87
What is a stepped or cone pulley drive?
A system of pulleys made up from
88
What does a step pulley consist of in terms of configuration?
2 to 4
89
When can the same belt tension be achieved?
When the sum of both working stages are identical
90
What is good about V ribbed belts?
They can run at high speeds
91
Why is pulley alignment critical to flat belts?
Because there is no chance of belt slip off
92
What is not advised with flat belts?
High outputs at high speeds
93
What are modern belts made out of?
Aluminium and nylon with rubberised plastic
94
What do timing belts not rely on?
Friction

mod 6 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions