Mini Project on Suspension System Icf Bogie

7/31/2019 Mini Project on Suspension System Icf Bogie

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MINI PROJECT REPORT

ON

SUSPENSION SYSTEM OF AN ICF BOGIE

At

South central railway, carriage workshop

Lallaguda, Secunderabad.

Dissertation work submitted to Jawaharlal Nehru Technology University.

In partial fulfillment of the requirements of the award of

BACHELOR OF TECHNOLOGY

IN

MECHANICAL ENGINEERING

BY

T.KIRAN KUMAR S.SREEDHAR REDDY P.PRANAY KUMAR B.CHARITHA

097Z1A0345 097Z1A0343 097Z1A0339 097Z1A0309

NALLA NARASIMHA REDDY EDUCATION SOCIETYS

GROUP OF INSTITUTIONS

Chowdhariguda, Korremula X Road via Narapally, Ghatkesar (mandal), Ranga Reddy (DIST)- 500088


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ACKNOWLEDGEMENT

With deep sense of gratitude, I acknowledge the guidance, help and active cooperation render by

the following people whose guidance has sustained the effort which lead to the successful

completion of the project.

I express my deep sense of gratitude to Mr .T. PAVAN KUMAR, HOD, MECHANICAL

BRANCH and Mr.SURESH KUMAR(instructor) Of NALLA NARASIMHA REDDY

EDUCATION SOCIETYS GROUP OF INSTITUTIONS. For giving valuable guidance through

out the project.

We are grateful to Shri.S.VASUDEVAIAH, Dy.CME, lallaguda carriage workshop, for

providing us an opportunity to do this project in SCR.

We would like to thankMr.G. SATYA KUMAR, CI, BTC, for guiding us through our project.

He helped us at every stage in understanding and solving many problems encountered during thecourse of project.

We sincerely thankMr.T.N.RAMANA RAO, Junior Instructors of BTC, who directed us to

successful completion of project.

We would like to thank Mr. CHANDHRA SHEKAR, SSE, SMITHY SHOP and

MR.K. ANJANAILU, SSE, BOGIE SHOP, who in spite of their hectic schedule helped us in

carrying out our work and helped us in a great way by co-operating at every stage.

All together, working in SCR was a great learning experience. We would cherish our experience

in this organization for out life time


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ABSTRACT

Every vehicle has suspension system which provides comfort to driver and

passengers. Suspension system maintains traction between tyres and road which is

compulsory for every vehicle. It also protects the vehicle body from damages

during pitches and downs. In suspension system, springs play major role because it

takes load of vehicle and transfer it to wheels.

As every vehicle is equipped with suspension system we have selected this

project and explained about suspension system of a railway bogie including its

process of over hauling.

Hope this is useful for every mechanical student.

.


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INDEX

ACKNOWLEDGEMENT

ABSTRACT

INTRODUCTION

INDIAN RAILWAYS

SOUTH CENTRAL RAILWAY

LALLAGUDA WORKSHOP

SUSPENSION SYSTEM

INTRODUCTION

COMPONENTS

IMPROTANCE

PRINCIPLE

CONCEPT OF RIDE QUALITY

SUSPENSION SYSTEM OF ICF BOGIE

TYPES OF BOGIES

INTRODUCTION TO ICF(ALL COILED) BOGIE

PRIMARY SUSPENSION SYSTEM SECONDARY SUSPENSION SYSTEM

PROCEDURE OF OVER HAULING OF SUSPENSION SYSTEMS

OF ICF BOGIE

OVER HAULING OF PRIMARY SUSPENSIONSYSTEM

OVER HAULIG OF SECONDARY SUSPENSIONSYSTEM

ADVANTAGES OF SUSPENSION SYSTEM

SUGGESTIONS

CONCLUSION


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INTRODUCTION TO SUSPENSION SYSTEM

Suspension system is the term given to the system of springs, shock absorbers and

linkages that connects a vehicle to its wheels. It is basically cushion for passengers,

protects the luggage or any cargo and also itself from damage and wear.

Sir William Brush is the father of suspension system in automobiles.

It is located between the wheel axles and the vehicle body, also call frame.


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COMPONENTS OF SUSPENSION SYSTEM

SPRINGS

DAMPERS

ANTI SWAY BARS OR LINKAGES

SPRINGS

DEFINITION FOR SPRING:

Springs are elastic bodies (generally metal) that canbe twisted, pulled, or stretched

by some force. They canreturn to their original shape when the force is released. In

other words it is also termed as a resilient member.

CLASSIFICATION OF SPRINGS:

Based on the shape behavior obtained by some applied force, springs are classified

into the following ways:

SPRINGS

HELICAL SPRINGS LEAF SPRINGS

SPIRAL SPRINGS

TORSION SPRING

TENSION HELICAL

SPRING COMPRESSION HELICAL SPRIGS


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HELICAL SPRINGS:-

DEFINITON:

It is made of wire coiled in the form of helix.

CROSS-SECTION:

Circular, square or rectangular

CLASSIFICATION:

1.Closed coil springs (or) Tension helical springs

2. Open coil springs (or) Compression helical springs

3. TORSION SPRINGS

4. SPIRAL SPRING

1)HELICAL TENSION SPRINGS:-

CHARACTERISTICS:

Figure1 shows a helical tension spring. It has some means of transferring the

load from the support to the body by means of some arrangement.

It stretches apart to create load.

The gap between the successive coils is small.

The wire is coiled in a sequence that the turn is at right angles to the axis of

the spring. The spring is loaded along the axis.

By applying load the spring elongates in action as it mainly depends upon

the end hooks as shown in figure2.


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FIGURE1.TENSION HELICAL SPRING

FIGURE2.TYPES OF END HOOKS OF A HELICAL EXTENSION SPRING

APPLICATIONS:

Garage door assemblies

Vise-grip pilers

Carburetors


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2) HELICAL COMPRESSION SPRINGS:-

CHARACTERISTICS:

The gap between the successive coils is larger.

It is made of round wire and wrapped in cylindrical shape with a constant pitch

between the coils.

By applying the load the spring contracts in action.

There are mainly four forms of compression springs as shown in figure3.. They

are as follows:

Plain end

Plain and ground end

Squared end

Squared and ground end

Among the four types, the plain end type is less expensive to

manufacture. It tends to bow sideways when applying a

compressive load.

FIGURE3.COMPRESSION HELICAL SPRING


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APPLICATIONS:

Ball point pens

Pogo sticks

Valve assemblies in engines

Suspension system of automobiles

3) TORSION SPRINGS:-

CHARACTERISTICS:

It is also a form of helical spring, but it rotates about an axis to create load.

It releases the load in an arc around the axis as shown in figure4.

Mainly used for torque transmission

The ends of the spring are attached to other application objects, so that if the

object rotates around the center of the spring, it tends to push the spring to

retrieve its normal position.

FIGURE4.TORSION SPRING

APPLICATIONS:

Mouse tracks

Rocker switches

Door hinges


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Clipboards

Automobile starters

4) SPIRAL SPRINGS:-

CHARACTERISTICS:

It is made of a band of steel wrapped around itself a number of times to

create a geometric shape, as shown in figure5.

Its inner end is attached to an arbor and outer end is attached to a retaining

drum.

It has a few rotations and also contains a thicker band of steel.

It releases power when it unwinds.

APPLICATIONS:

Alarm timepiece

Watch

Automotive seat recliners

FIGURE5. SPIRAL SPRING


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LEAF SPRING:-

DEFINITION:

A Leaf spring is a simple form of spring commonly used in the suspension

vehicles.

.LEAF SPRING

CHARACTERISTICS:

Figure shows a leaf spring. Sometimes it is also called as a semi-

elliptical spring, as it takes the form of a slender arc shaped length of

spring steel of rectangular cross section.

The center of the arc provides the location for the axle,while the tie

holes are provided at either end for attaching to the vehicle body.

Heavy vehicles,leaves are stacked one upon the other to ensure

rigidity and strength.

It provides dampness and springing function.

It can be attached directly to the frame at the both ends or attached

directly to one end,usually at the front,with the other end attached

through a shackle,a short swinging arm.

The shackle takes up the tendency of the leaf spring to elongate when

it gets compressed and by which the spring becomes softer.

Thus depending upon the load bearing capacity of the vehicle the leaf

spring is designed with graduated and Un-graduated leaves as shown

in figure7.


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FIGURE7.LEAF SPRINGS-FABRICATION STAGES

Because of the difference in the leaf length,different stress will be

there at each leaf.To compensate the stress level,pre-stressing is to be

done.Pre-stressing is achieved by bending the leaves to different

radius of curvature before they are assembled with the center clip.

The radius of curvature decreases with shorter leaves.

The extra in-tail gap found between the extra full length leaf and

graduated length leaf is called as nip.Such pre-stressing achieved by a

difference in the radius of curvature is known as nipping which is

shown in figure8.

FIGURE8.NIPPING IN LEAF SPRINGS

APPLICATIONS:

Mainly in automobiles suspension systems.


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ADVANTAGES:

It can carry lateral loads.

It provides braking torque.

It takes driving torque and withstand the shocks provided by the

vehicles.

SPRING MATERIALS:

The mainly used material for manufacturing the springs are as follows:

Hard drawn high carbon steel.

Oil tempered high carbon steel.

Stainless steel.

Copper or nickel based alloys.

Phosphor bronze.

Iconel.

Monel.

Titanium.

Chrome vanadium.

Chrome silicon.

Depending upon the strength of the material,the material is slected for the design

of the spring as shown in figure9.


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NOMENCLATURE OF SPRING

Active Coils

Those coils which are free to deflect under load.

Angular Relationship of ends

The relative position of the plane of the hooks or loops of extension spring to each

other.

Buckling

Bowing or lateral deflection of compression springs when compressed, related to

the slenderness ration (L/D).

Closed Ends

End of compression springs where the pitch of the end coils is reduced so that the

end coils touch.

Closed and Ground Ends

As with closed ends, except that the end is ground to provide a flat plane.

Close-Wound

Coiled with adjacent coils touching.

Deflection

Motion of the spring ends or arms under the application or removal of an external

load.

Elastic Limit

Maximum stress to which a material may be subjected without permanent set.


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Endurance Limit

Maximum stress at which any given material may operate indefinitely without

failure for a given minimum stress.

Free Angle

Angel between the arms of a torsion spring when the spring is not loaded.

Free Length

The overall length of a spring in the unloaded position.

Frequency (natural)

The lowest inherent rate of free vibration of a spring itself (usually in cycles per

second) with ends restrained.

Hysteresis

The mechanical energy loss that always occurs under cyclical loading and

unloading of a spring, proportional to the arc between the loading and unloading

load-deflection curves within the elastic range of a spring.

Initial Tension

The force that tends to keep the coils of an extension spring closed and which must

be overcome before the coil starts to open.

Loops

Coil-like wire shapes at the ends of extension springs that provide for attachment

and force application.

Mean Coil Diameter

Outside wire diameter minus one wire diameter.


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Modulus in shear or torsion

Coefficient of stiffness for extension and compression springs.

Modulus in tension or bending

Coefficient of stiffness used for torsion and flat springs. (Young's modulus).

Open ends, not ground

End of a compression spring with a constant pitch for each coil.

Open ends ground

"Opens ends, not ground" followed by an end grinding operation.

Permanent Set

A material that is deflected so far that its elastic properties have been exceeded and

it does not return to its original condition upon release of load is said to have taken

a "permanent set".

Pitch

The distance from center to center of the wire in adjacent active coils.

Spring Rate (or) Stiffness (or) Spring Constant

Changes in load per unit of deflection, generally given in Kilo Newton per meter.

(KN/m).

Remove Set

The process of closing to a solid height a compression spring which has been

coiled longer than the desired finished length, so as to increase the elastic limit.

Set

Permanent distortion which occurs when a spring is stressed beyond the elastic

limit of the material.


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Slenderness Ratio

Ratio of spring length to mean coil diameter.

Solid Height

Length of a compression spring when under sufficient load to bring all coils into

contact with adjacent coils.

Spring Index

Ratio of mean coil diameter to wire diameter.

Stress Range

The difference in operating stresses at minimum and maximum loads.

Squareness of ends

Angular deviation between the axis o a compression spring and a normal to the

plane of the other ends.

Squareness under load

As in squarenessof ends,

except with the spring under load.

Torque

A twisting action in torsion springs which tends to produce rotation, equal to the

load multiplied by the distance (or moment arm) from the load to the axis of the

spring body. Usually expressed in inch-oz, inch-pounds or in foot-pounds.

Total number of coils

Number of active coils plus the coils forming the ends.

Spring Index

The ratio between Mean dia of coil to the diameter of the wire.


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Solid length

It is the product of total number of coils and the diameter of the wire when the

spring is in the compressed state. It is otherwise called as Solid height also.

FIGURE10.NOMENCLATURE OF SPRING


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FIGURE11.HELICAL SPRING IN LOADED END CONDITION

Depending upon the type of the compression helical spring the numbers of coils are decided as

shown in figure12.The Pitch angle is calculated as shown in figure13.

FIGURE12.RELATION BETWEEN ENDS AND NOMENCLATURE OF A

COMPRESSION HELICAL SPRING

FIGURE13.RELATION BETWEEN PITCH AND MEAN DIAMETER OF COIL


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DAMPERS

Shock absorbers, linear dampers, and dashpots are devices used as dampers in

suspension system of a vehicle. They may be mechanical (e.g., elastomeric) or rely

on a fluid (gas, air, hydraulic), which absorbs shock by allowing controlled flow

from outer to inner chamber of a cylinder during piston actuation. The piston rod is

typically returned to the unloaded position with a spring. Shock absorbers

typically contain both a fluid or mechanical dampening system and a return

mechanism to the unengaged position. They generally used in automobiles. Linear

dampers is an inclusive term that can be applied to many forms of dashpots and

shock absorbers; typically used for devices designed primarily for reciprocatingmotion attenuation rather than absorption of large shock loads. Dashpots are

typically distinct in that while they use controlled fluid flow to dampen and

decelerate motion, they do not necessarily incorporate an integral return

mechanism such as a spring. Dashpots are often relatively small, precise devices

used for applications such as instrumentation and precision manufacturing.

IMPORTANCE AND WORKING OF DAMPERS


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Unless a dampening structure is present, a vehicle spring will extend and release the

energy it absorbs from a bump at an uncontrolled rate. The spring will continue to bounce

at its natural frequency until all of the energy originally put into it is used up. A

suspension built on springs alone would make for an extremely bouncy ride and,depending on the terrain, an uncontrollable car.

Enter the dampers, or snubber, a device that controls unwanted spring motion through a

process known as dampening. Shock absorbers slow down and reduce the magnitude of

vibratory motions by turning the kinetic energy of suspension movement into heat energy

that can be dissipated through hydraulic fluid. To understand how this works, it's best to

look inside a shock absorber to see its structure and function.

A shock absorber is basically an oil pump placed between the frame of the car and the

wheels. The upper mount of the shock connects to the frame (i.e., the sprung weight),

while the lower mount connects to the axle, near the wheel (i.e., the un-sprung weight). In

a twin-tube design, one of the most common types of shock absorbers, the upper mount is

connected to a piston rod, which in turn is connected to a piston, which in turn sits in a

tube filled with hydraulic fluid. The inner tube is known as the pressure tube, and the

outer tube is known as the reserve tube. The reserve tube stores excess hydraulic fluid.

When the car wheel encounters a bump in the road and causes the spring to coil and

uncoil, the energy of the spring is transferred to the shock absorber through the upper

mount, down through the piston rod and into the piston. Orifices perforate the piston and

allow fluid to leak through as the piston moves up and down in the pressure tube.

Because the orifices are relatively tiny, only a small amount of fluid, under great

pressure, passes through. This slows down the piston, which in turn slows down the

spring.

Shock absorbers work in two cycles -- the compression cycle and the extension cycle.

The compression cycle occurs as the piston moves downward, compressing the hydraulic


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fluid in the chamber below the piston. The extension cycle occurs as the piston moves

toward the top of the pressure tube, compressing the fluid in the chamber above the

piston. A typical car or light truck will have more resistance during its extension cycle

than its compression cycle. With that in mind, the compression cycle controls the motionof the vehicle's un-sprung weight, while extension controls the heavier, sprung weight.

All modern shock absorbers are velocity-sensitive -- the faster the suspension moves, the

more resistance the shock absorber provides. This enables shocks to adjust to road

conditions and to control all of the unwanted motions that can occur in a moving vehicle,

including bounce, sway, brake dive and acceleration squat.

ANTISWAYBARS OR LINKAGES

An anti-sway bar or anti-roll bar or stabilizer bar is a part of

an automobilesuspension, that helps reduce the body roll of a vehicle during fast

cornering or over road irregularities. It connects opposite (left/right) wheels

together through short lever arms linked by a torsion spring. A sway bar increases

the suspension's roll stiffnessits resistance to roll in turns, independent of

its spring ratein the vertical direction. The first stabilizer bar patent was awarded to

the Canadian S. L. C. Coleman of Fredericton, New Brunswick on April 22, 1919.

PURPOSE AND OPERATION

An anti-sway or anti-roll bar is intended to force each side of the vehicle to lower,

or rise, to similar heights, to reduce the sideways tilting (roll) of the vehicle on

curves, sharp corners, or large bumps. With the bar removed, a vehicle's wheels
http://en.wikipedia.org/wiki/Leverhttp://en.wikipedia.org/wiki/Torsion_springhttp://en.wikipedia.org/wiki/Torsion_springhttp://en.wikipedia.org/wiki/Lever


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can tilt away by much larger distances (as shown by theSUV image at right).

Although there are many variations in design, a common function is to force the

opposite wheel's shock absorber, spring or suspension rod to lower, or rise, to a

similar level as the other wheel. In a fast turn, a vehicle tends to drop closer onto

the outer wheels, and the sway bar will soon force the opposite wheel to also get

closer to the vehicle. As a result, the vehicle tends to "hug" the road, closer in a fast

turn, where all wheels are closer to the body. After the fast turn, then the

downward pressure is reduced, and the paired wheels can return to their normal

height against the vehicle, kept at similar levels by the connecting sway bar.

Because each pair of wheels is cross-connected by a bar, then the combined

operation causes all wheels to generally offset the separate tilting of the others, and

the vehicle tends to remain level against the general slope of the terrain. A negative

side-effect, of connecting pairs of wheels, is that a jarring or bump to one wheel

tends to also jar the opposite wheel, causing a larger impact applied across the

whole width of the vehicle. If there are several potholes scattered in the road, then

a vehicle will tend to rock, side-to-side, or waddle, due to the action of the bar at

each pair of wheels. Other suspension techniques can be used to delay, or dampen,

the effect of the connecting bar, as when hitting small holes which momentarily

jolt just a single wheel, whereas larger holes or longer tilting would then tug the

bar with the opposite wheel.

PRINCIPLE

A sway bar is usually a torsion spring that resists body roll motions. It is usually

constructed out of a wide, U-shaped steel bar that connects to the body at two

points, and at the left and right sides of the suspension. If the left and right wheels

move together, the bar rotates about its mounting points. If the wheels move
http://en.wikipedia.org/wiki/Sports_Utility_Vehiclehttp://en.wikipedia.org/wiki/Shock_absorberhttp://en.wikipedia.org/wiki/Shock_absorberhttp://en.wikipedia.org/wiki/Sports_Utility_Vehicle


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relative to each other, the bar is subjected to torsion and forced to twist. Each end

of the bar is connected to an end linkthrough a flexible joint. The sway bar end link

in turn connects to a spot near a wheel or axle, permitting forces to be transferred

from a heavily-loaded axle to the opposite side.

Forces are therefore transferred:

from the heavily-loaded axle

to the connected end link via a bushing

to the anti-sway (torsion) bar via a flexible joint

to the connected end link on the opposite side of the vehicle

to the opposite axle.

The bar resists the torsion through its stiffness. The stiffness of an anti-roll bar is

proportional to the stiffness of the material, the fourth power of its radius, and the

inverse of the length of the lever arms (i.e., the shorter the lever arm, the stiffer the

bar). Stiffness is also related to the geometry of the mounting points and the

rigidity of the bar's mounting points. The stiffer the bar, the more force required to

move the left and right wheels relative to each other. This increases the amount of

force required to make the body roll.

In a turn the sprung mass of the vehicle's body produces a lateral force at the center

of gravity (CG), proportional to lateral acceleration. Because the CG is usually not

on the roll axis, the lateral force creates a moment about the roll axis that tends toroll the body. (The roll axis is a line that joins the front and rear roll centers

(SAEJ670e)). The moment is called the roll couple.

Roll couple is resisted by the suspension roll stiffness, which is a function of the

spring rate of the vehicle's springs and of the anti-roll bars, if any. The use of anti-
http://en.wikipedia.org/wiki/Torsion_(mechanics)http://en.wikipedia.org/wiki/Torsion_(mechanics)


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roll bars allows designers to reduce roll without making the suspension's springs

stiffer in the vertical plane, which allows improved body control with less

compromise of ride quality

One effect of body (frame) lean, for typical suspension geometry, is

positive camber of the wheels on the outside of the turn and negative on the inside,

which reduces their cornering grip (especially with cross ply tires).


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IMPORTANCE OF SUSPENSION SYSTEM

Suspension system allows the vehicle to travel over rough surfaces with a

minimum of up and down body movements. It also allows the vehicle to corner

with minimum roll or tendency to loose traction between the tires and road surface.

The suspension provides a cu-shioning effect action, therefore, the passengers or

move up and down they meets bumps and holes in the road.

THE MAIN IMPORTANCE OF SUSPENSION SYSTEM ARE :

Support the weight of vehicle

Maintain traction between the tires and the road

It supports the weight of vehicle

Provides smoother ride for the driver and passengers i.e. acts as cushion.

Protects your vehicle from damage and wear .

It also plays a critical role in maintaining self- driving conditions.

It also keeps the wheels pressed firmly to the ground for traction

It isolates the body from road shocks and vibrations which would otherwise

be transferred to the passengers and load.

Good handling

Shields the vehicle from damage

Increases life of vehicle keeps the tires pressed firmly to ground


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PRINCIPLE OF SUSPENSION

PRINCIPLE

When a tire hits an obstruction, there is a reaction force. The size of this reaction

force depends on the un-sprung mass at each wheel assembly.

In general, the larger the ratio of sprung weight to un-sprung weight, the less the

body and vehicle occupants are affected by bumps, dips, and other surface

imperfections such as small bridges. A large sprung weight to un-sprung weight

ratio can also impact vehicle control.

DEFINITIONS OF SPRUNG &UNSPRUNG MASS

Sprung mass:-Sprung mass (weight) refers to vehicle parts supported on the

suspension system, such as the body, frame, engine, the internal components,

passengers, and cargo.

Un-sprung mass:- Un-sprung mass refers to the components that follow the road

contours, such as wheels, tires, brake assemblies, and any part of the steering and

suspension not supported by the springs.

WORKING OF SUSPENSION SYSTEM

No road is perfectly flat i.e. without irregularities. Even a freshly paved highways

have subtle forces on wheels.

According to Newton law of motion all forces have both magnitude and direction.

A bump in the road causes the wheel to move up and down perpendicular to the

road surface. The magnitude of course, depends on whether the wheel is striking a

giant bump or a tiny speck. Thus, either the wheel experiences a vertical

acceleration as it passes over an imperfection.


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CONCEPT OF RIDE QUALITY

DEFINITION

Ride quality refers to the degree of protection offered vehicle occupants from

uneven elements in the road surface, or the terrain if driving off-road. A car with

very good ride quality is also a comfortable car to ride in. Cars which disturb

vehicle occupants with major or minor road irregularities would be judged to have

low ride quality. Key factors for ride quality are Whole body vibrationand noise.

IMPORTANCE

While pleasant, the comfort of the vehicle driver is also important for car safety,

both because of driver fatigue on long journeys in uncomfortable vehicles, and also

because road disruption can impact the driver's ability to control the vehicle. Early

vehicles with its live axle suspension design, were both uncomfortable and handled

poorly.

Automakers often perceive providing an adequate degree of ride quality as a

compromise with car handling, because cars with firm suspension offer more roll

stiffness, keeping the tires more perpendicular to the road. Similarly, a lower center

of gravity is more ideal for handling, but low bodywork forces the driver's and

passengers' legs more forward and less down, and low ground clearance limits

suspension travel, requiring stiffer springs. Ride quality is also related to good

braking and acceleration on poor surfaces. It protects the car itself, as well as its

passengers and cargo, from vibration that might eventually damage or loosen

components of the car.
http://en.wikipedia.org/wiki/Roadhttp://en.wikipedia.org/wiki/Terrainhttp://en.wikipedia.org/wiki/Off-roadhttp://en.wikipedia.org/wiki/Whole_body_vibrationhttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Car_safetyhttp://en.wikipedia.org/wiki/Fatigue_(medical)http://en.wikipedia.org/wiki/Live_axlehttp://en.wikipedia.org/wiki/Car_handlinghttp://en.wikipedia.org/wiki/Suspension_(vehicle)http://en.wikipedia.org/wiki/Suspension_(vehicle)http://en.wikipedia.org/wiki/Car_handlinghttp://en.wikipedia.org/wiki/Live_axlehttp://en.wikipedia.org/wiki/Fatigue_(medical)http://en.wikipedia.org/wiki/Car_safetyhttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Whole_body_vibrationhttp://en.wikipedia.org/wiki/Off-roadhttp://en.wikipedia.org/wiki/Terrainhttp://en.wikipedia.org/wiki/Road


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On the other hand "poor" ride quality improves blood circulation, helps to keep the

driver awake, helps the driver sense speed and road condition and is enjoyed by

small children and traditional sportscar enthusiasts.

Ride quality is depend on ride index, ride index is the ratio of sprung mass to un-

sprung mass.

The quality of ride low in two conditions i.e.

1.When ride index value is low

2. When ride index value is high.

The quality of ride is high when ride index value is in b/w 15 to 35.

Ride quality is also dependson type of suspension system used.


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INTRODUCTUION TO ICF BOGIE

Bogie or trolley is a main part of a train where it takes load from coach and transfer

it to wheel axel through suspension systems.

CHARACTERSITICS OF ICF BOGIE

It is an independent unit used under a long vehicle.

It is usually mounted on two pairs of wheels.

(In exceptional cases, such as special purpose stocks or high capacity vehicles of

well Wagons or crocodile trucks, inspection carriages etc.. the bogie may be

mounted on three or more pairs of Wheels)

Normally two bogies are used under a Vehicle.

Each bogie carries half the load of the vehicle body and its loading.

Each bogie is provided with a pivot on its central transom or bolster for

engagement with its male counterpart provided underneath the vehicle under

frame.

TYPES OF BOGIES USED IN INDIAN RAILWAYS:

IRS Bogie

SCHLIEREN Bogie (ICF Laminated Bogie)

MAN-HAL Bogie (BEML Bogie)

ICF All Coiled Bogie

IR-20 Bogie

Fiat Bogie (Similar to IR-20 Bogie)


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INTRODUCTION TO ICF (ALL COILED) BOGIE

ICF Bogie is a conventional railway bogie used on the majority of Indian Railway

main line passenger coaches. The design of the bogie was developed by ICF

(Integral Coach Factory), Perumbur, India in collaboration with the Swiss Car &

Elevator Manufacturing Co., Schlieren, Switzerland in the 1950s. The design is

also called the Schlieren design based on the location of the Swiss company.

BOGIE FRAME

The frame of the ICF bogie is a fabricated structure made up of mild steel channels

and angles welded to form the main frame of the bogie. The frame is divided into

three main sections. The first and the third section are mirror images of each other.

Various types of brackets are welded to the frame for supporting bogie

components.


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BOGIE BOLSTER

The body bolster is a box type fabricated member made up of channels and welded

to the body of the coach. It is a free-floating member. The body bolster transfers

the dead weight of the coach body to the bogie frame. There are two type of

bolsters in an ICF bogie: body bolster and the bogie bolster. The body bolster is

welded to the coach body whereas the bogie bolster is a free floating member

which takes the entire load of the coach through the body bolster.In body bolster

there are 2 side bearers and a center pivot pin are joined by excellent quality

welding. These three parts acts as a male part and matches with the female part

welded to bogie bolster. These are very vital parts for smooth running of a train.


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CENTER PIVOT PIN

A center pivot pin is bolted to the body bolster. The center pivot pin runs down

vertically through the center of the bogie bolster through the center pivot. It allows

for rotation of the bogie when the coach is moving on the curves. A silent block,

which is cylindrical metal rubber bonded structure, is placed in the central hole of

the bogie bolster through which the center pivot pin passes. It provides the

cushioning effect.

Centre Pivot


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WHEEL SET ASSEMBLY:

Wheel arrangement is of Bo-Bo type as per the UIC classification. The wheel set

assembly consists of two pairs of wheels and axle. The wheels may be cast wheels

or forged wheels. The wheels are manufactured at Durgapur Steel Plant of SAIL(

Steel authority of India Ltd.) or at Wheel and Axle Plant of Indian Railways bases

at Yelahanka near Banglore in the state of Karnataka. At times, imported wheels

are also used. These wheels and axles are machined in the various railway

workshops in the wheels shops and pressed together.

ROLLER BEARING ASSEMBLY:

Roller bearings are used on the ICF bogies. These bearings are press fitted on the

axle journal by heating the bearings at a temperature of 80 to 100 C in an

induction furnace. Before fitting the roller bearing , an axle collar is press fitted.

The collar ensures that the bearing does not move towards the center of the axle.

After pressing the collar, a rear cover for the axle box is fitted. The rear cover has

two main grooves. In one of the grooves, a nitrile rubber sealing ring is placed. The

sealing ring ensures that the grease in the axle box housing does not seep out

during the running of the wheels. A woolen felt ring is placed in another groove.


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After the rear cover, a retaining ring is placed. The retaining ring is made of steel

and is a press fit. The retaining ring ensures that the rear cover assembly is secured

tightly between the axle collar and the retaining ring and stays at one place. The

roller bearing is pressed after the retraining ring. Earlier, the collar and the bearings

were heated in an oil bath. But now the practices has been discontinuedand an

induction furnace is used to heat them before fitting on the axle. The axle box

housing, which is a steel casting, is then placed on the axle. The bearing is housed

in the axle box housing. Axle box grease is filled in the axle box housing. Each

axle box housing is filled with approximately 2.5 kg. of grease. The front cover for

the axle box is placed on a housing which closes the axle box. The front cover is

bolted by using torque wrench.

BRAKE BEAM ASSEMBLY

ICF bogie uses two types of brake beams. 13 ton and 16 ton. Both of the brake

beams are fabricated structures. The brake beam is made from steel pipes and

welded at the ends. The brake beam has a typical isosceles triangle shape. The two

ends of the brake beam have a provision for fixing a brake head. The brake head in

turn receives the brake block. The material of the brake block is non-asbestos, and

non-metallic in nature.


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BRAKE HEAD

Two types of brake heads are used. ICF brake head and the IGP brake head. A

brake head is a fabricated structure made up of steel plates welded together.

BREAK BLOCKS

Brake blocks are also of two types. ICF brake head uses the "L" type brake block

and the "K" type brake block is used on the IGP type brake head. "L" & "K" types

are so called since the shape of the brake blocks resembles the corresponding

English alphabet letter. The third end of the brake beam has a bracket for

connecting the "Z" & the floating lever. These levers are connected to the main

frame of the bogie with the help of steel brackets. These brackets are welded to the

bogie frame.

BRAKE LEVERS

Various type of levers are used on the ICF Bogie .The typical levers being the "Z"

lever, floating lever and the connecting lever. Theses levers are used to connect the

brake beam with the piston of the brake cylinder. The location of the brake

cylinders decides whether the bogie shall be a BMBC Bogie or a non BMBC

Bogie. Conventional bogies are those ICF bogies in which the brake cylinder is

mounted on the body of the coach and not placed on the bogie frame itself.

BRAKE CYLINDER

In a ICF Bogie, the brake cylinder is mounted on the bogie frame itself.

Traditionally, the ICF Bogies were conventional type i.e. the brake cylinder was

mounted on the body of the coach. However, in the later modification, the new

bogies are being manufactured with the BMBC designs only. Even the old type

bogies are being converted into BMBC Bogies. The BMBC bogie has many

advantages over the conventional ICF bogie. The foremost being that, since the


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brake cylinder is mounted on the bogie frame itself and is nearer to the brake

beam, the brake application time is reduced. Moreover, a small brake cylinder is

adequate for braking purpose. This also reduces the overall weight of the ICF

bogie apart from the advantage of quick brake application.

PRIMARY SUSPENSION

The primary suspension in a ICF Bogie is through a dashpot arrangement. The

dashpot arrangement consists of a cylinder (lower spring seat) and the piston (axle

box guide). Axle box springs are placed on the lower spring seat placed on the axle

box wing of the axle box housing assembly. A rubber or a Hytrel washer is placed

below the lower spring seat for cushioning effect. The axle box guide is welded to

the bogie frame. The axle box guide acts as a piston. A homopolymer acetyle

washer is placed on the lower end of the axle box guide. The end portion of the

axle box guide is covered with a guide cap, which has holes in it. A sealing ring is

placed near the washer and performs the function of a piston ring. The axle box

guide moves in the lower spring seat filled with dashpot oil. This arrangement

provides the dampening effect during the running of the coach.


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SECONDARY SUSPENSION

The secondary suspension arrangement of the ICF bogies is through bolster

springs. The bogie bolster is not bolted or welded anywhere to the bogie frame. It

is attached to the bogie frame through the anchor link. The anchor link is a tubular

structure with cylindrical housing on both the ends. The cylindrical housings have

silent blocks placed in them. The anchor link is fixed to the bogie bolster and the

bogie frame with the help of steel brackets welded to the bogie bolster and the

bogie frame. Both the ends of the anchor link act as a hinge and allow movement

of the bogie bolster when the coach is moving on a curved track.

LOWER SPRING BEAM

The bolster springs are supported on a lower spring beam. The lower spring beam

is a fabricated structure made of steel plates. It is trapezoidal in shape with small

steel tubes on each end. The location of the bolster spring seating is marked by two

circular grooves in the center. A rubber washer is placed at the grooved section.

The bolster spring sits on the rubber washer. The lower spring beam is also a free-

floating structure. It is not bolted or welded either to the bogie frame or the bogie

bolster. It is attached to the bogie frame on the outside with the help of a steel

hanger. They are traditionally called the BSS Hangers (Bogie Secondary

Suspension Hangers). A BSS pin is placed in the tubular section in the end portion

of the lower spring beam. A hanger block is placed below the BSS pin. The BSS

hanger in turn supports the hanger. This arrangement is done on all the four corners

of the lower spring beam. The top end of the hanger also has a similar


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arrangement. However, instead of the BSS pin, steel brackets are welded on the

lower side of the bogie frame of which the BSS hanger hangs with the help of

hanger block. This arrangement is same for all the four top corners of the hangers.

Hence, the lower spring beam also become a floating member hinged to the bogie

frame with the help of hangers on the top and the bottom. This allows for thelongitudinal movement of the lower spring beam.

EQUALIZING STAY ROD

The inner section of the lower spring beam is connected to the bogie bolster with

the help of an equalizing stay rod. It is a double Y-shaped member fabricated using

steel tubes and sheets. The equalizing stay rod is also hinged on both the ends with

the lower spring beam as well as the bogie bolster with the help of brackets weldedto the bogie bolster. They are connected through a pin making it a hinged

arrangement.


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SUSPENSION OF ICF (ALL COILED) BOGIE

An ICF Bogie consist of two types of suspension system they are :

Primary Suspension System or Axel Box Suspension System.

Secondary Suspension System or Bolster Suspension System.

PRIMAR SUSPENSION SYSTEM

Since every suspension system consists of springs and dampers , so in this system

we use helical compression springs as suspension spring an dashpot arrangement

as dampers.

Primary suspension system of ICF bogie consist of following components:

Axle box guide with dashpot arrangement.

Axle box helical compression spring

Derling washers & Hydral washer

Packing rings

AXLE BOX GUIDE DASHPOT ARRANGEMENT

Axle box guide with dashpot arrangement is mainly a cylinder piston arrangement

used on the primary suspension of Indian Railway coaches of ICF design. The

lower spring seat acts as a cylinder and the axle box guide acts as a piston.

The dashpot guide arrangement has the following main components:

Lower Spring Seat, Lower Rubber Washer, Compensating Ring, Guide Bush, Dust

Shield ring,Circlip, Dust Shield Spring, Protective Tube with Upper Rubber

Washer, Axle Box Guide Screw with sealing washer.


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The axle box guide (piston) is welded to the bottom flange of the bogie side frame.

Similarly, the lower Spring seat(cylinder) is placed on the axle box housing wings

forms a complete dashpot guide arrangement of the ICF design coaches.

Axle box guides traditionally had a guide cap with 9 holes of 5mm diameter each;

however, in the latest design, the guide cap is made an integral part of the guide.

Approximately 1.5 liters of dashpot oil is required per guide arrangement.

Air vent screws are fitted on the dashpot for topping of oil so that the minimum oil

level is maintained at 40mm.

Traditionally, rubber washers have been used at the seating arrangement of the

primary springs of the axle box housing in the ICF design passenger coaches on

the Indian Railways. The rubber washer is used directly on the axle box seating

area. the lower spring seat sits on the washers. The lower spring seat is a tubular

structure and 3/4 section is partitioned by using a circular ring which is welded at

the 3/4 section. On the top of spring seat, a polymer ring called NFTC ring sits.

The primary spring sits on the NFTC ring. The lower spring seat plays the role of a

cylinder in the dashpot arrangement and is filled with oil. In the dashpot

arrangement, the top portion is called the axle box guide. The axle box guide is

welded to the bogie frame. The axle box guide works as a piston in the Lower

spring seat filled with oil. This helps in damping the vibrations caused during

running train operation.

The axle box guide, which is welded to the bogie frame has a polymer washer

(homo-polymer acetal guide) bush fixed at the head. A polymer packing ring and a

guide ring is attached with the Acetal guide bush. These two components act as

piston rings for the axle box guide. In order to ensure that the packing ring and the


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guide ring retain their respective place, a dashpot spring is fixed which applies

continuous pressure on the piston ring.

The bottom of the axle box guide has a guide cap with perforations so that during

the downward movement of the axle guide in the lower spring seat, the oil in the

dashpot rushes in the axle box guide. This provides the dampening of vibration in a

running coach.

The guide cap is fixed with the help of a steel circlip. However in the new design

of Axle box guide, the guide cap is welded with the guide assembly and hence the

need of a guide cap has been eliminated. The complete guide and lower springarrangement is covered with a dashpot cover also known as protective tube. The

protective tube has a circular ring over it called the dust shield which prevents the

ingress of the dust in the cylinder piston arrangement of the dashpot.


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AXLE BOX HELICAL COMPRESSION SPRING

Here helical compression springs are used in primary suspension system which

are made up of chrome vanadium/chrome molybdenum steel. The diameter of coil

approximately 245mm. Dimensions and working load of some axle box springs are

given below.

Figure 3.2a

UNDERTARE

ASSEMBLING

142.5

104

SEALING WASHER

2. GUIDE

3. PROTECTIVETUBECOMPLETE

4. UPPERRUBBERWASHER

5. TOP SPRING SEAT

6. DUSTSHIELD SPRING

7. DUSTSHIELD

8. HELICALSPRING

9. GUIDERING

10. RUBBERPACKING RING

11. GUIDEBUSH

12. CIRCLIP

13. C OMPENSATING RING

14. LOWERRUBBERWASHER

15. SAFETYSTRAP

16. LOWERSPRING SEAT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

1516

1. SPECIALSEREWWITH

POWERCAR-

EXCEPTPOWERCARS

686 FORALLAC & NON-AC COACHES

XTO RAILLEVEL-

XTOR

AILLEVEL

OILLEVELBEFORE

OIL LEVEL

670 FORBOGIEON LUGGAGESIDE

672 FORBOGIEON GENERATORSIDE

92.5

40

MODIFIED AXLE BOX GUIDE ARRANGEMENT


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Axle box compression springs with dash pot arrangement

(primary suspension system)

DERLING AND HYDRAL WASHERS

They are used in primary suspension system in order to isolate the migrations

caused by wheel and it gives perfect seating for axle box compression. They are

made up of high density molecular poly utherane.

DERLING WASHER HYDRAL WASHER


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PACKING RINGS

These are used in primary suspension system to get equal buffer head. Since all

wheels have different diameters(due to unequal wear of wheels) in order to get

same buffer head the packing rings of different dimensions are to be used in

primary suspension system.

PACKING RINGS

SECONDARY SUSPENSION SYSTEM

The main function of Secondary suspension system of icf bogie is to transfer the

coach load from bloster to bogie frame through BSS hangers .

The main components of secondary system are:-

Bolster

Lower spring beam

Bolster compression springs

BSS hangers

BSS block

BSS pin

Equalizing stay rod

Anchor link

Shock absorber


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BOLSTER

The body bolster is a box type fabricated member made up of channels and welded

to the body of the coach. It is a free-floating member. The body bolster transfers

the dead weight of the coach body to the bogie frame. There are two type of

bolsters in an ICF bogie: body bolster and the bogie bolster. The body bolster is

welded to the coach body whereas the bogie bolster is a free floating member

which takes the entire load of the coach through the body bolster.In body bolster

there are 2 side bearers and a center pivot pin are joined by excellent quality

welding. These three parts acts as a male part and matches with the female part

welded to bogie bolster. These are very vital parts for smooth running of a train.

Bogie Bolster

LOWER SPRING BEAM

The bolster springs are supported on a lower spring beam. The lower spring beam

is a fabricated structure made of steel plates. It is trapezoidal in shape with small

steel tubes on each end. The location of the bolster spring seating is marked by two


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circular grooves in the center. A rubber washer is placed at the grooved section.

The bolster spring sits on the rubber washer. The lower spring beam is also a free-

floating structure. It is not bolted or welded either to the bogie frame or the bogie

bolster. It is attached to the bogie frame on the outside with the help of a steel

hanger. They are traditionally called the BSS Hangers (Bogie Secondary

Suspension Hangers). A BSS pin is placed in the tubular section in the end portion

of the lower spring beam. A hanger block is placed below the BSS pin. The BSS

hanger in turn supports the hanger. This arrangement is done on all the four corners

of the lower spring beam. The top end of the hanger also has a similar

arrangement. However, instead of the BSS pin, steel brackets are welded on the

lower side of the bogie frame of which the BSS hanger hangs with the help of

hanger block. This arrangement is same for all the four top corners of the hangers.

Hence, the lower spring beam also become a floating member hinged to the bogie

frame with the help of hangers on the top and the bottom. This allows for the

longitudinal movement of the lower spring beam.

LOWER SPRING BEAM


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BOLSTER COMPRESSION SPRINGS

Since it is a ICF all coiled bogie, helical compression springs are used in secondary

suspension system. They are made up of chrome vanadium/ chrome

molybdenumsteel. The mean diameter of bolster springs are approximately

324mm. Dimensions and safe working load of some bolster springs are given

below.

Load deflection testing and grouping of Bolster spring(B.G Main line coaches)

Code Wire

dia

Free

height

Test

Load

Acceptable

height under

test load

Groups as per loaded spring height

A B C

Yellow Oxford Blue

#

Green

B01 42 385 3300 301-317 301-305 306-311 312-317

B03 42 400 4800 291-308 291-296 297-303 304-308

B04 47 400 6100 286-304 286-291 292-297 298-304

B06 36 416 4200 280-299 280-286 287-292 293-299

B11 47386 6700 306-322 306-311 312-317 318-322

B13 34

B15 40 3936000 256-272 256-261 262-267 268-272

B16 32.5 286


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BSS HANGERS, BSS BLOCKS, BSS PINS

In secondary suspension system, the bolster is supported on helical coiled springs

which are placed on lower spring beam. The lower spring beam is suspended from

bogie side frame through BSS hangers on BSS hanger blocks. This BSS hanger

blocks are supported on BSS hanger pins which are attached in bogie frame.

BSS HANGERS BSS BLOCK

BSS PIN


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The figure shows assemble parts of BSS Hanger, BSS Block, BSS Pin

EQUALIZING STAY RO-

The inner section of the lower spring beam is connected to the bogie bolster with

the help of an equalizing stay rod. It is a double Y-shaped member fabricated using

steel tubes and sheets. The equalizing stay rod is also hinged on both the ends with

the lower spring beam as well as the bogie bolster with the help of brackets welded

to the bogie bolster. They are connected through a pin making it a hinged

arrangement.

Equalizing Stay Rod & Anchor Link


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ANCHOR LINK

It is a pin connection to the Bolster sides and the Bogie Transoms. The main

function of anchor link is to transfer braking/tractive force from bogie frame to

bolster and it restricts the rolling motion of bolster. It can swivel universally to

permit the bolster to rise and fall and sway side wards. One anchor link isprovided

on each side of the bolster diagonally across. Fitted with silent block bushes in

order to isolate vibrations from bogie frame. It holds in position longitudinally the

floating bogie bolster.

SHOCK ABSORBER

In order to decrease the unwanted oscillations during pitching, shock absorbers are

used as damper. Since secondary suspension of ICF Bogie has helical coil springs,to isolate unwanted oscillations of this spring a gabrieal or escort shock absorbers

are used.


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Figure shows a gabrieal hydraulic shock absorber with capacity of 600kg (i.e.,in

tensile and in compression) at a speed of 10cm/sec is fitted to work in parallel with

the bolster springs to provide damping for vertical oscillations.


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PROCEDURE OF OVER HAULING OF SUSPENSIONSYSTEMS

OF ICF BOGIE

Over hauling of primary suspension system

Over hauling of secondary suspension system

OVER HAULING OF PRIMARY SUSPENSION SYSTEM

The main components in primary suspension system to be over haul are:-

1) Axle box compression springs

2) Dash pot

3) Guide bush

4) Dearling and hydral washers or rubber pads

OVER HAULING OF SECONDARY SUSPENSION SYSTEM

The main compents in secondary suspension system to be over haul are:-

1) Bolster springs

2) BSS hangers

3)

BSS block and BSS pin4) Shock absorbers

5) Lower spring beam


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POH OFPRIMARY SUSPENSION SYSTEM

OVER HAULING OF AXLE BOX COMPRESSION SPRINGS:-

Steps to follow over hauling of axle box compression springs:-

Step 1:- After dismantling the bogie parts, the axle box compression springs are sent

to sand blasting chamber where these springs are cleaned with a blast of sand.

Step 2:- Now these springs are sent to Spring Section.

Step 3:- In spring section, these springs are cleaned completely from oil, grease,

scale etc. by putting them in a Bosch tank containing degreasing agents (soda ash:2%, caustic soda: 1% and tri sodium phosphate:1% in 5000 liters of water) for a

period of 8 hours and then followed by rinsing with hot water/steam to clean off

any residual chemicals.

Step 4:- Now inspect the spring visually under proper illumination for broken,

cracks, dents, tool marks, welding marks or corrosion pits. Springs having

cracks/dent/tool/welding marks or corrosion pitting should be rejected.


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Step 5:- Now accepted springs are sent in to shot blasting/ pining machine, where

springs are hit by a group of cast steel balls at a force of 25kg/sq.cm to improve

fatigue strength and this process also clean the surface of the spring from paints,

scales etcwhich are not perfectly cleaned in Bosch tank.

Shot blasting/pining machine

Step 6:- After shot blasting springs are subjected to Load Test on Hydraulic Load

Testing Machine. In this process the springs are tested for deflection on the

application of working loads for minute, if springs deflect beyond its range it is

rejected. The table shows the range of acceptable deflection limits of different

springs under specified working load and it also indicates grouping of springs withrespect to their deflection limits. Tie a single loop of sealing wire on one of the

coils of category A springs, two loops for B and three loops for C group.


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Load Testing Machine

Step 7:- After this process, springs are sent to Magna Flux Crack Detection Test in

order to identify cracks which are not visible by naked eye. In this Magna Flux

Crack Detection Test springs are first magnetized with the help of electric current,

after magnetization a fluorescent liquid containing small iron particles suspended

in water. Now the cracked spring is detected under ultra violet rays if spring


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contains any cracks which are not visible to naked eye. By this way cracked spring

is rejected in this process.

Magna flux crack detecting machine Cracked detected under ultra violet rays

Step 8:- After crack detecting test, the accepted springs should be given one coat of

Red Oxide Zinc Chromate and followed by a coat of Black Japan in order to get

better abrasion resistance and corrosion resistance.

Step 9:- The springs have to be painted with colour codes which are grouped with

respective to their deflection ranges.

Spring group Color code

A Yellow

B Oxford Blue

C Green


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Step 10:- Then similar colour code springs are kept in a bin, which are used in a

same bogie.

OVER HAULING OF DASHPOTS

Steps to follow over hauling of Dash Pots:-

Step 1:- After dismantling the bogie parts, the dash pots are sent to sand blasting

chamber, where it is cleaned by blast of sand.

Step 2:- Then it is sent to Bogie section, where it is visually checked for cracks,

dents, deformation etc..If they are detected, the dash pot is rejected.

Step 3:- Acceptable dash pots are sent to assemble section for reuse.

Over hauling of Dash Pots


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OVER HAULING OF GUIDE BUSH

Steps to follow over hauling of Guide bush:-

Step 1:- Since guide is permanently attached to bogie frame hence it is cleaned

along with bogie frame.

Step 2:- After tramling of bogie frame the guide is visually checked for damages. If

any damages are detected the guide is separated from bogie frame with the help of

gas cutter.

Step 3:- The guide bush of a guide is replaced in every POH.

Over hauling of Guide bush

OVER HAULING OF DEARLING AND HYDRAL WASHERS

Steps to follow over hauling of Dearling and hydral washers:-

Step 1:- After dismantling dearling and hydral washers from bogie, they are sent to

bearing chamber where they are cleaned with the help of saw dust.

Step 2:- Check the washers for wear, cracks, dents etc.. if any of them is found the

washers are rejected and replaced with new one.


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Dearling washer Hydral washers

POH OF SECONDARY SUSPENSION SYSTEM

OVR HAULING OF BOLSTER HELICAL COMPRESSION SPRINGS:-

Steps to follow over hauling of bolster helical compression springs:-

Step 1:- After dismantling the bogie parts, the bolster helical compression springs

are sent to sand blasting chamber where these springs are cleaned with a blast of

sand.

Step 2:-Now these springs are sent to Spring Section.

Step 3:- In spring section, these springs are cleaned completely from oil, grease,

scale etc. by putting them in a Bosch tank containing degreasing agents (soda ash:

2%, caustic soda: 1% and tri sodium phosphate:1% in 5000 liters of water) for a

period of 8 hours and then followed by rinsing with hot water/steam to clean off

any residual chemicals.


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Step 4:- Now inspect the spring visually under proper illumination for broken,

cracks, dents, tool marks, welding marks or corrosion pits. Springs having

cracks/dent/tool/welding marks or corrosion pitting should be rejected.

Step 5:- Now accepted springs are sent in to shot blasting/ pining machine, where

springs are hit by a group of cast steel balls at a force of 25kg/sq.cm to improve

fatigue strength and this process also clean the surface of the spring from paints,

scales etcwhich are not perfectly cleaned in Bosch tank.

Shot blasting/pining machine


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Step 6:-After shot blasting springs are subjected to Load Test on Hydraulic Load

Testing Machine. In this process the springs are tested for deflection on the

application of working loads for minute, if springs deflect beyond its range it is

rejected. The table shows the range of acceptable deflection limits of different

springs under specified working load and it also indicates grouping of springs with

respect to their deflection limits. Tie a single loop of sealing wire on one of the

coils of category A springs, two loops for B and three loops for C group .

Load Testing Machine


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Step 7:-After this process, springs are sent to Magna Flux Crack Detection Test in

order to identify cracks which are not visible by naked eye. In this Magna Flux

Crack Detection Test springs are first magnetized with the help of electric current,

after magnetization a fluorescent liquid containing small iron particles suspended

in water. Now the cracked spring is detected under ultra violet rays if spring

contains any cracks which are not visible to naked eye. By this way cracked spring

is rejected in this process.

Magna flux crack detecting machine Cracked detected under ultra violet rays

Step 8:- After crack detecting test, the accepted springs should be given one coat of

Red Oxide Zinc Chromate and followed by a coat of Black Japan in order to get better

abrasion resistance and corrosion resistance.


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Step 9:- The springs have to be painted with colour codes which are grouped with

respective to their deflection ranges.

Spring group Color code

A Yellow

B Oxford Blue

C Green

Step 10:- Then similar colour code springs are kept in a bin, which are used in a

same bogie.

OVER HAULING OF BSS HANGERS:-

Steps to follow over hauling of BSS Hangers:-

Step 1:-Check the cleaned hangers for cracks and wear. Replace the hangers if

cracked or wear exceeds 1mm. Magna flux crack detection equipment shall be

used for checking.


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Step 2:-The horizontal wearing surface may be built up using 2B electrodes, filed

and ground to size. Then hard powder coating may be applied. Hardness value

should be 55-60 RH.

Step 3:-The vertical gap should be within the permissible limit i.e., 384-386 mm.

All the hangers should be tested to tensile load of 8 tones and replaced if any

permanent set is observed in the hangers.

Step 4:-After repair and testing all the BSS hangers should be painted with one coat

of anti corrosive back paint. Write the actual length between the wearing arms on

the BSS hanger with paint.

BSS HANGERS REJECTED BSS HANGER

OVER HAULING OF BSS BLOCK AND BSS PIN

Steps to follow over hauling of BSS block and BSS pin:-

Step 1:- Check the cleaned BSS block and BSS pin for dimensions, cracks and

wear.

Step 2:- Reject them if any change in dimensions beyond its limits, cracks or wears

are appeared.


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Step 3:- Acceptable blocks and pins are sent to assemble section to reuse.

Step 4:- Apply colour code as yellow for acceptable pins and red for rejected pins.

OVER HAULING OF SHOCK ABSORBERS

Steps to follow over hauling of Shock Absorbers:-

Step 1:-Periodicity overhaul

a) Schedule overhaul:- shock absorbers should be given a schedule

overhaul:

When their capacities vary beyond 20% of their specified values,

or

After 4 lakh kilometers or alternate POH, whichever is earlier.

b) Non schedule overhaul:- shock absorbers should also be overhauled

whenever suspected to be defective. Which is indicated primarily by oil

lekage or when they are physically damaged.

Step 2:-Testing

a) The shock absorber is tested on the special purpose machine (RDSO

sketch mos. 69.2.04.00 to 69.2.04.08) which can measure its capacity in

both tension and compression by developing the resisting force at a


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velocity of 10cm/sec. the length of shock absorber and its stroke should

be within the limits specified.

b) The shock absorber must be tested at every POH and reused if

overhauling is not due and its capacity is within 20%. A register should

be maintained in the shock absorber section wherein the test results of

each shock absorber should be recorded before the shock absorber is

certified fit for use on coaches.

Step 3:- After the testing and certification, the protection cover of the shock

absorber should be pressed into position on the piston rod disc and spot welding at

six points around the periphery.

Step 4:- The shock absorber should then be extended on the mounting fixture and

painted. When the paint dries, it should be compressed and then removed from the

fixture.

Step 5:- The dare of testing, the date of overhauling and the name of the shop where

overhauled should invariably be stamped on the name plate o shock absorber

before it is sent for fitment.

OVER HAULING OF LOWER SPRING BEAM

Steps to follow over hauling of Lower spring beam:-

Step 1:-Check the lower spring beam (plank) for cracks, corrosion, etc. and repair

or replace as required.


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Step 2:- The following parts of the lower spring plank should be inspected and

repaired or replaced as required:

Bolster suspension straps if bent or damaged

Stay rod brackets if worm, bent or corroded

Shock absorber fixing bosses if damaged

Spring guide rings If required

Lug if damaged

Step 3:- Replace the following parts:

Bushes of BSS brackets of worm beyond permissible limits Equalizing stay brackets bushes

BSS pins If worm beyond permissible limits.

Step 4:- The locations where the repairs have been carried out or found corroded out

or found corroded should be cleaned to bare metal and painted with two coats of

primer to IS:2074 to a minimum Dry Film Thickness (DFT) of 50 microns

followed by one coat of anti-corrosive Black Japan Type-B to IS:341 to a DFT of

35 microns, after which entire lower spring beam is to be given one coat of Black

Japan Type-B to IS:341 to a minimum DFT of 35 microns.

Lower spring beam


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ADVANTAGES

Comfort to the passengers

Good handling

Shields the vehicle from damage

Increases the life of the vehicle

Keep the tires pressed firmly to the ground


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SUGGESTION

Suspension system of a ICF bogie mainly fails due to failure of springs andimproper assembly.

Since failure of springs is mainly due to improper hardness, we would suggest that

to involve a heat treatment process of springs during over hauling in order to get

desire hardness.

A special care should be taken during assembly of suspension system in order to

avoid failure due to improper assembly


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CONCLUSION

From the whole discussion in suspension system, I observe that suspension system

is like a white blood cell .As white blood cell provides energy to our body to fight

against diseases or viruses which try to destroy or try to decrease our life ,in the

similar way suspension system provides the energy to a vehicle to protect itself

from damaging, increasing life of the vehicle ,increases the handing, increases

comfort of passengers and many more.

So, according to me if you remove the suspension system, then you feel like in

bull- cart in Audi, Mercedes types luxurious cars. The only difference is speed.

So, the scope of Suspension System is Too Bright.

Mini Project on Suspension System Icf Bogie

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Transcript of Mini Project on Suspension System Icf Bogie