introduction to gears , types & gear trains.

1. GEARS
By Tayaba Qurban (K-15ME-05)

2. Introduction:
 Have you ever tried pedaling a bicycle
up a really steep hill?
 It's pretty much impossible unless you
use the right gear to increase your
climbing force.
 Once you're back on the straight, it's a
different story.
 Flick to a different gear and you can
go incredibly fast: you can magically
make your wheels turn round much
faster than you're pedaling.

3. Importance:
 Gears are helpful in machines of all kinds, not
just cars and cycles.
 They're a simple way to generate more speed
or power or send the power of a machine off in
another direction.

4. Gears are used for transmitting power from
one part of a machine to another.
What do gears do...

5. Gears can do one of three
things:
 Increase speed: If you connect two gears
together and the first one has more teeth than
the second one, the second one has to turn
round much faster to keep up but with less
force.
 Increase force: If the second wheel in a pair of
gears has more teeth than the first, it turns
slower than the first one but with more force.
 Change direction: When two gears mesh
together, the second one always turns in the
opposite direction.

6. How do they do it…??
You can see exactly how
they work.

7.  Spur Gears
 Helical Gears
 Rack & Pinion Gears
 Idler Gears
 Worm & wheel Gears
 Bevel Gears
Types of gears

8. Spur Gears
 Are used in transmitting torque between
parallel shafts
Driver
gear
Driven
gear
Spur Gears

9.  Are used in transmitting torques between
parallel or non parallel shafts.
 operate with less noise and vibration than spur
gears.
Helical Gears

10. Rack and Pinion
 The rack and pinion gear is used to
convert between rotary and linear motion.

11. Idler gear
Idler gear
Driver
Driven
Only use to change the
direction:

12. Worm gear and wheel
 Are used for transmitting motion between
non parallel and non transmitting shafts
 The worm gear is always the drive gear
Worm and wheel

13. Bevel gears
 Are used to transmit rotary motion
between intersecting shafts
Bevel Gears

14. Two or more gears are made to mesh with
each other to transmit power from one shaft
to another.
Gear trains

15. Types of Gear Trains:
 Simple gear train
 Compound gear train
 Reverted gear train
 Epicyclic gear train

16. Simple Gear Train
 Multiple gears can be connected together to
form a gear train.
Each shaft carries only
one gear wheel.
Intermediate gears are
known as Idler Gears.

17. Compound Gear Train
 If two gear wheels are mounted on a common
shaft then it’s a Compound Gear train.
Driver
Compound
Gear
Driven

18. Reverted Gear Train
When the axes of the first gear (first driver) and
the last gear (last driven or follower) are
coaxial, then the gear train is known as
reverted gear train.
 In a reverted gear train, the motion of the first
gear and the last gear is like.

19. Epicyclic Gear Train
 In epicyclic gear trains, the axes of the shafts
on which the gears are mounted may move
relative to a fixed axis.

20. Gear Speed
 A motor gear has 28 teeth and revolves at 100
rev/min. The driven gear has 10 teeth. What is
its rotational speed?
Speed of driven gear = Number of teeth on driver gear x 100
Number of teeth on driven gear
Speed of driven gear = driver = 28 x 100 = 280 rev/min
driven 10
28 teeth,
driver
10 teeth,
driven

21. sOlvE the PuzZleEe…

22. Thanx