Date post: | 04-Jun-2018 |
Category: |
Documents |
Upload: | david-mbikayi |
View: | 227 times |
Download: | 0 times |
of 50
8/14/2019 Gears & Drives
1/50
Gears & Drives
MEC1010Design and Manufacturing 1
Dr. Simon Smith
8/14/2019 Gears & Drives
2/50
Gears & Drives
Massive subject, for your wind turbines
consider:
How to transmit the turbine power to the
generator
Gearing (speed / torque changes) to match
the speed of the turbine to the speed required
at the generator
Friction losing power between the turbine and
the generator
8/14/2019 Gears & Drives
3/50
Gears & Drives
Transmission of power from source to load
8/14/2019 Gears & Drives
4/50
Gears & Drives
Power source should match load
Engine size to weight of vehicle / performance
required
Turbine size to generator
Consider power losses (friction)
Drive system should be sized appropriately
Clutches, drive shafts, belts
Power / torque / speed
8/14/2019 Gears & Drives
5/50
GEARBOX
GEARBOX
PROP SHAFT
DRIVE SHAFTS
DRIVE SHAFT
DRIVE SHAFT
UNIVERSAL JOINTS
8/14/2019 Gears & Drives
6/50
Transmissions
In British English the term transmission refers
to the whole drive train
Gearbox, clutch, prop shaft, differential, drive
shafts, universal joints, belts, chains, etc
In American English the term transmission
refers only to the gearbox
8/14/2019 Gears & Drives
7/50
Commercial Wind Turbine
8/14/2019 Gears & Drives
8/50
Spur Gears
Simplest of gears
Teeth parallel to
shaft
Rotate on two
parallel shafts
8/14/2019 Gears & Drives
9/50
Direction of Rotation Changes
8/14/2019 Gears & Drives
10/50
Gearing
Ratio of teeth
10:28
speed reducing
28:10
speed increasing
Fixed ratio
8/14/2019 Gears & Drives
11/50
Gears
Can vary in:
Diameter
Width
No. of teeth Material
Tooth form
Gear form
8/14/2019 Gears & Drives
12/50
Where have you seen spur gears?
8/14/2019 Gears & Drives
13/50
Where have you seen spur gears?
8/14/2019 Gears & Drives
14/50
Multiple designs this year
will probably use small spur gears
8/14/2019 Gears & Drives
15/50
Bevel Gears
Allows angle of drive
to be changed
Gearing ratio can bechanged, although
this is 1:1
8/14/2019 Gears & Drives
16/50
Where have you seen bevel gears?
8/14/2019 Gears & Drives
17/50
Where have you seen bevel gears?
8/14/2019 Gears & Drives
18/50
And some designs this year
will probably use bevel gears
8/14/2019 Gears & Drives
19/50
Linear (Rack & Pinion) Gears
Rack can moverelative to shaft
Steering on a car
Shaft can movealong rack
Positional changes
Some swing bridges
Pinion
Rack
8/14/2019 Gears & Drives
20/50
Internal / External Gears
Relative positionchanges
Gearing
Rotation Example might be a
food mixer
8/14/2019 Gears & Drives
21/50
Worm Gears
Screw
Worm wheel
Large gear ratio Often non-reversible & self-locking
8/14/2019 Gears & Drives
22/50
Helical Gears
Teeth set at an angle toaxis of rotation
Advantages
Smoother
Quieter
High speed
Large power transmission
Direction change possible
Disadvantages
Expense
More sliding friction
Axial thrust
8/14/2019 Gears & Drives
23/50
Belt Drives
Simple
Quiet
Smooth
Can tolerate load
changes
No lubrication
required
8/14/2019 Gears & Drives
24/50
Belt Drives
Cheap
Can cope with
misalignment
Can be veryefficient 95%
Can be very
inefficient too!
Can provide
gearing
8/14/2019 Gears & Drives
25/50
Belt must be tensioned correctly
8/14/2019 Gears & Drives
26/50
Belt must be tensioned correctly
8/14/2019 Gears & Drives
27/50
Minimize misalignment
8/14/2019 Gears & Drives
28/50
Widely varying applications
8/14/2019 Gears & Drives
29/50
Can be used as a clutch
8/14/2019 Gears & Drives
30/50
Belt Types
8/14/2019 Gears & Drives
31/50
Timing Belt / Cambelt
Toothed belt
High speed
Reliable
Cheap
Accurate timing
8/14/2019 Gears & Drives
32/50
Some designs this year
will probably use belt drives
8/14/2019 Gears & Drives
33/50
Chain Drive
Strong
Less prone to slipping
Flexible
Usually narrower than a
belt for same power
transmission
Many applications, butoften used in transport
& vehicles
8/14/2019 Gears & Drives
34/50
Chain Drive
Can be cheap
Can provide gearing
Can cope with some
misalignment
As with belt drives -
Tension correctly
Align correctly
8/14/2019 Gears & Drives
35/50
Chain Drive
8/14/2019 Gears & Drives
36/50
Chain drive in biscuit manufacture
8/14/2019 Gears & Drives
37/50
This year we will
probably see chain drives
8/14/2019 Gears & Drives
38/50
Flexible Drives
Power can be
transmitted through
large angles
Minimal assembly
Can be low friction
Can accommodate load
changes
8/14/2019 Gears & Drives
39/50
Flexible Couplings
Allow power transmission
Allow for misalignment
Absorb shock loads
Can protect against
overloads
Can be torque limiting in
some cases
8/14/2019 Gears & Drives
40/50
Flexible Couplings
8/14/2019 Gears & Drives
41/50
Your Design WILL have at least 1
FLEXIBLE COUPLING
8/14/2019 Gears & Drives
42/50
Examples of drive systems
Petrol engine
Shaft drive
Bevel gear
Cutting head
8/14/2019 Gears & Drives
43/50
Many Ways to Transmit Power
Straight shaft drive Bent shaft drive
8/14/2019 Gears & Drives
44/50
Wind Turbines
Straight shaft connection
Gearing is 1:1Should be low friction
Wind shadow?
8/14/2019 Gears & Drives
45/50
Wind Turbines
Parallel shaft connection
Gearing could now be altered
Probably more friction
8/14/2019 Gears & Drives
46/50
Wind Turbines
Perpendicular shafts
Gearing could be altered
Friction likely to increase
Alignment an issue
8/14/2019 Gears & Drives
47/50
Commercial Wind Turbine
8/14/2019 Gears & Drives
48/50
Commercial Wind Turbines
8/14/2019 Gears & Drives
49/50
What WILL Your Design Have?
Blades
Drive system
Bearings
Flexible coupling
Generator
8/14/2019 Gears & Drives
50/50
What Might Your Design Have?
Rigid coupling(s)
More bearings
Another flexible coupling
Gearing
Belt, Chain, Spur, Bevel, etc.