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Traction and Tractive Effort.pptx
1. JSPM’S
Department of Mechanical Engineering
B Tech
Automobile Engineering-Seminar Presentation
Subject Teacher:- Prof.A.D.Dharmadhikari
Name: Shubham Bhimrao Bangar
Topic: Traction And Tractive Effort
Roll.No.:-R105
Rajarshi Shahu College Of Engineering,
Pune
2. CONTENTS:-
Introduction to Traction.
What is Traction and Tractive Effort ?
Tractive resistance.
What is traction control ?
Need of traction control?
Necessity.
What is the direction of traction ?
3. TRACTION:-
What is Traction ?
Traction is defined as friction between a drive member(wheel) and the
surface it moves upon.
It is the amount of force a wheel can apply to a surface before it slips.
A rolling wheel is in static contact with the ground if it is not slipping.
4. TRACTIVE EFFORTS:-
The force available at the contact between the drive wheel tyres and road is
known as “Tractive Effort”.
The ability of the drive wheel to transmit this effort without slipping is known
as “Traction”.
It is amount of force a wheel can apply to a surface before it slips.
A wheel have different traction on different surfaces, as the coefficient of
friction is based on pairs of surfaces
The tractional force is equal to the frictional force between the wheel and
the ground
When the wheel is rolling along and not slipping, it is equal to the static
friction.
If the applied force exceeds the maximum static friction then the wheel will
start to slip, and now the tractive force is equal to the maximum kinetic
friction.
Hence usable tractive effort never exceeds traction.
5. Tractive Force or Tractive Effort:-
Tractive force or traction is the force applied between the tire and road
surface to move a car or any vehicle for that matter.
6. TRACTIVE EFFORT:-
The effect force acting on the wheel of locomotive to
propel the train is known as “Tractive Effort”(Ft).
The tractive effort is a vector quantity acting tangential
to wheel of locomotive .
The net effect force is equal to the sum of tractive effort.
A)required for linear and angular acceleration(Fa).
B)to overcome the effect of gravity(Fg).
C)to overcome the friction resistance to the motion of the train(Fr)
Fc=Fa+Fg+Fr
7. Tractive Force of vehicle:-
The maximum permissible traction that can be applied to the wheels is
governed by two things.
1) Weight of the vehicle and the adhesion coefficient between the tire and
road surface.
2)More the weight and the adhesion coefficient,more amount of the tractive
force can be applied to the wheel without causing slips between the tire and
road.
8. Tractive resistance:-
Tractive resistance:- tractive resistance create due to the motion of vehicle.
It consist of
i) resistance due to gradient.
ii) type of the road.
iii) tyre friction
9. Tractive Force Calculation:-
Applied tractive force based on engine power can be calculated as,
When the tractive effort F>R, the total resistance on level road, the surplus tractive
effort is utilized for acceleration, hill climbing and draw-bar pull.
10. Traction control system:-
The traction control means to increase or decrease the
traction at drive wheels so that the vehicle is able to
move and pull the applied load.
We can also say that the traction control is to control the
tractive effort at the running gears to overcome all kinds
of resistance and pull.
Tractive effort>(Rolling Resistance+ Gradient
Resistance+ Implement Resistance+ Other loss.es)
11. Traction Control system:-
The traction control is close monitoring of the situation that each of the
wheel is in.
This is one of the most important feature in roading vehicle.
Sometimes, one or more wheels might be on water,ice,sand,rocks or in the
air.
Depending on the situation ,the traction control system provide breaking
force or torque to the wheel.
12. Methods of Traction control
1) Tyre inflation Pressure: by decreasing the inflation
pressure, surface contact area is increased and the
traction is also increased.
2) Tyre tread design: tyre tread pattern, and depth of lugs
effects the traction.
3)Using tracks and chains: by these type of running gear,
more traction is available.
4)Putting additional weight: it is done to increase
traction.
5) Ballasting: ballasting means filling water or sand in
tyres to increase weight. This also increase traction.
6) Dynamic Weight Transfer: By transferring implement
weight towards the traction tyres also increase traction.
13. Need Of Traction Control:-
There should be sufficient amount of resistance
between the traction members(tyres) and the
soil for the tractor to be able to move and pull
the load.
If the soil is strongest and the force is applied by
the wheel on it, the soil does not break and it
applies equal force on the wheels. As a result the
tractor starts to move.
If the soil is soft, it breaks and the traction tyres
start to slip.
To avoid such slippages, we need to change the
traction.
14. TYPES OF TRACTION SYSTEM:-
System of Traction:
A) Non-Electric traction system:
Ex. steam engine drive
ic engine drive
B) Electric traction:
Ex. Diesel electric drive
gas turbine electric drive
