The document summarizes key components and functions of power transmission systems. It discusses the basic functions like selecting speed ratios, reversing travel, connecting/disconnecting power, and equalizing power for turning. The five basic components are identified as the clutch, gearbox system, differential, final drive, and drive wheels. The clutch connects and disconnects power. The gearbox selects speed and direction. The differential equalizes power for turning. The final drive reduces speed and increases torque. The drive wheels propel the machine. The document then provides more details on the clutch, mechanical transmission, differential, final drive, power take-off systems, tractor wheels, and tires.

1. POWER
TRANSMISSION

2. Four basic functions of transmission
systems are:
1. Select speed ratios for various travel speeds
2.Reverses the travel of the machine
3.To connect and disconnect power
4.Equalizes power to the drive wheels for
turning

3. Five basic components of the power
transmission are :
i. Clutch – to connect and disconnect power
ii. Gearbox system – to select speed and direction
iii.Differential – to equalize power for turning
iv. Final drive – to reduce speed and increase torque to axle
v. Drive wheels – to propel the machine
“Torque” - The effort of twisting or turning

4. The Clutch
Provides meaning of connecting and
disconnecting the engine from its load while
starting, shifting or idling
a) Dry clutch – standard clutch
b)Hydraulic clutch – operates wet in a
transmission fluid and engaged or disengaged
hydraulically

5. Dry Clutch
• The clutch operates by friction; the disks and
plates must be kept perfectly dry

6. Engaged position
Pressure plates provides pressure against clutch
plate and forces plate against flywheel
Power from engine transmitted to flywheel and
clutch plate and transmitted to drive shaft
Disengaged position
Pressure on pedal pushes clutch release assembly
against release levers
Lever pulls pressure plate away from clutch plate
and is no longer forced against flywheel
Flywheel and pressure plate are free to rotate

7. Mechanical Transmission
is a train of gears that transfer and adapts the engine power
to the drive wheels of the machine
the transmission can also power a special drive such as
PTO (power take-off)
located to the rear of the engine and clutch and in front of
the differential or ring gear
the gear train operates in a bath of gear oil. For special
lubrication, oil sprays or feeder lines from oil pumps are
sometimes used

8. The Differentials
Does two jobs:
Transmit power “around the corner” to the drive axles
Allows each drive wheels to rotate at different speed and
still propel its own load
Ring Gear and Bevel Gears:
Direct the power to the axles
Bevel pinions give the differential action

9. The Final Drives / Final Gear
Reduction
• The final drive is the last phase of the power
train
• It gives the final reduction in speed and
increased in torque to the drive wheels
• Mounted near the drive wheels to avoid the
stress of long axle shaft
• By reducing speeds, the final drives lower the
stress and simplify the transmission, since
extra gears and shafts can be eliminated

10. Power Take-Off (PTO) –
Construction & Operation
• Is an attachment in the power train of a
machine. It drives auxiliary equipment
• Normally gear driven from the transmission
and send power through a shaft to the PTO
outlet where the driven equipment is coupled
• Drive equipment at standard speed of 540 –
1000 rpm
• Operated by a clutch release, which is
sometimes part of the main engine clutch

11. 3 Types of PTO
1. PTO, Normal Type
PTO takes its rotation from the engine through
the same clutch as the gearbox therefore
engaging the clutch starts both the tractor and the
PTO

12. 2. PTO, Live type
Clutch of the dual plate type controlled
progressively by a pedal
One clutch plate drives the gearbox and the other
drives the PTO
To disengage gearbox, press pedal halfway
through its travel. To disengage PTO, press pedal
to the bottom of its travel
By pressing halfway, it is possible to leave PTO
turning and at the same time stopping the tractor

13. 3.PTO, Fully independent type
Tractor provided with 2 clutches, one for
gearbox and the other for PTO
2 clutches controlled by pedal and lever. It is
possible to stop the PTO leaving the tractor
moving

14. Tractor Wheels
• Tractor wheels are made of cast iron or steel.
Most rear wheels have inner cast iron disks
and hubs with steel rims
• Most front wheels are made of steel but some
are constructed with inner cast iron wheels and
steel outer rims

15. Tires
There are many different types of tractor tires,
each suited to a specific operation. Tires vary in
construction and tread design.

16. a) Rear Tires
Four kinds of rear tire treads
Standard or general purpose cleat
familiar with “V” tread are a compromise
among traction, flotation and tread life. Best
all round tire for majority of farm uses
High cleat
provides maximum traction
in mud but tread wears rapidly if
operated on hard ground or paved
surfaces

17. Nondirectional
Gives good traction and flotation
in loose or sandy soil.
Provides sideslip control on slopes,
smoother ride, and longer wear on hard
surfaced and leaves no imprint on lawns
Industrial Lug
for on and off the road utility
tractors for earthmoving
the short wide bars give more contact
area for longer tread wear, more
traction than nondirectional tread

18. b) Front Tires
Comes in a variety of tread designs to provide the best
steering control
Single rib
effective where loose soil
makes steering a problem
Double rib and triple rib
found on many general
purpose tractors.
Gives good steering control
in average soil condition
without excessive soil
compaction

19. Flotation
used where soil compaction is a problem
tires are wider and have a lower profile than other
front tires. While reducing compaction, these tires
also make steering more difficult

20. Rice tread
used where field conditions are exceptionally wet.
Usually have 2 or 3 deep ribs for better steering
control and to help tire the tire roll through muddy
soil

21. Angle bar
similar to those on the rear of the tractor
used on tractors with front wheel drive and may
either standard cleats or cane or rice cleats

22. THANK YOU