Introduction:
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NAME :
BRANCH :
ROLL NO. :
SANDEEP
M.E.
12321
TRAINING INFO:
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TRAINEE AT:
BRANCH:
DEPARTMENT:
CHEVROLET
HISAR
DENTING,
ASSEMBELING
PAINTING
WHEEL ALIGNMENT
The beginning of a journey called life!
It all started in an experimental workshop in a Detroit garage and it
continues today in garages all over the world. William Durant, a
successful buggy manufacturer from Flint, Michigan, asked Louis
Chevrolet, a well known car racer, to help him design a car for the
general public. Chevrolet got named after its designer because
Durant liked the sound of the name and because Chevrolet was a
prominent name in motor sports.
The company was established in 1911, and the bowtie logo first
appeared in 1914. Legend maintains that the bowtie shape was
inspired by a pattern of wallpaper in a Paris hotel room. William
Durant reportedly detached a small piece and kept it in his wallet,
waiting for the day he’d put it to use. The bowtie has, since then,
become an advertising icon, and is still the marquee of today's
Chevrolet.
Of Vibhushan Chevrolet Hisar
M.D. –
Abhishek Gupta
Superviser:
Body Shop Manager:
Foreman:
Samunder Singh
Bhoop Singh
Sunil
CHEVROLET
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CHEVROLET is a leading Automobile
Industry in India.
It is the branch of GENERAL MOTORS, no.
1 international automobile company.
Chevrolet was racing car industry initialy
established by a racer William Durant, a
successful buggy manufacturer from Flint,
Michigan, and Louis Chevrolet, a well
known car racer.
CHEVROLET
 Its
products are:
-BEAT
-SPARK
-CAPTIVA
-CRUIZE
-TAVERA
-AVEO
BRIEF OF MY TRAINING:
From 16th June, 2011 to 28th July
16th June to 25th June:
 26th June to 13th July:
 14th July to 18th July:
 19th July to 24th July:
 24th July to 28th July:
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- Denting
- Assembling
- Painting
- Wheel alignment
- Under Superviser
STUDY OF WHEEL BALANCING
Tire balance, also referred to as tire unbalance or imbalance,
describes the distribution of mass within an automobile
tire or the wheel to which it is attached. When the tire
rotates, asymmetries of mass cause the wheel to wobble,
which can cause ride disturbances, usually vertical and
lateral vibrations. It can also result in a wobbling of the
steering wheel. The ride disturbance, due to unbalance,
usually increases with speed. Vehicle suspensions can
become excited by tire unbalance forces when the speed of
the wheel reaches a point that its rotating frequency
equals the suspension’s resonant frequency.
CONTINUE….
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Tires are inspected in factories and repair shops by two
methods: static balancers and dynamic balancers. Tires
with high unbalance forces are downgraded or rejected.
When tires are fitted to wheels at the point of sale, they
are measured again, and correction weights are applied to
counteract the combined effect of the tire and wheel
unbalance. After sale, tires may be rebalanced if driver
perceives excessive vibration
Static balance
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Static balance can be measured by a static balancing
machine where the tire is placed in its vertical axis on a
non-rotating spindle tool. The spot on the tire with the
greatest mass is acted upon by gravity to deflect the
tooling downward. The amount of deflection indicates the
magnitude of the unbalance. The angle of the deflection
indicates the angular location of the unbalance. In tire
manufacturing factories static balancers operate by use of
sensors mounted to the spindle assembly.
CONTINUE….
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. In tire retail shops static balancers are most usually nonrotating bubble balancers, where the magnitude and angle
of the unbalance is observed by looking at the center
bubble in an oil-filled glass sighting gauge. While some very
small shops which lack specialized machines still do this
process, they have been largely replaced in larger shops
with machines.
Dynamic balance:
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Dynamic balance describes the forces generated by
asymmetric mass distribution when the tire is rotated,
usually at a high speed. In the tire factory the tire is
mounted on a balancing machine test wheel, the assembly
is accelerated up to a speed of 300 RPM or higher, and
sensors measure the forces of unbalance as the tire rotates.
These forces are resolved into static and couple values for
the inner and outer planes of the wheel, and compared to
the unbalance tolerance (the maximum allowable
manufacturing limits)
CONTINUE….
If the tire is not checked, it has the potential to wobble
and perform poorly. In tire retail shops tire/wheel
assemblies are checked on a spin-balancer, which
determines the amount and angle of unbalance. Balance
weights are then fitted to the outer and inner flanges of
the wheel. Dynamic balance is better (it is more
comprehensive) than static balance alone, because both
couple and static forces are measured and corrected.
CONTINUE….
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The dynamic balance can only be conducted if the driver
comes to garage and has the garage check for imbalances.
With the increased use of electronics, the unbalance or
imbalance condition might be estimated by electronics in
real-time and independent of the driver's detection
capability. Recently, a SAE paper did the exactly same:
using sensors such as the ABS wheel speed sensors for a
brake control module to detect an imbalanced tire or tires
in real-time.
The physics of dynamic balance
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Physics of tire imbalance
Mathematically, the moment of inertia of the wheel is a
tensor. That is, to a first approximation (neglecting
deformations due to its elasticity) the wheel and axle
assembly are a rigid rotor to which the engine and brakes
apply a torque vector aligned with the axle. If that torque
vector is not aligned with the principal axis of the
moment of inertia, the resultant angular acceleration will
be in a different direction from the applied torque.
Whenever a rotor is forced to rotate about an axis that is
not a principal axis, an external torque is needed.
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This is not a torque about the rotation axis (as in a driving
or braking torque), but is a torque perpendicular to that
direction. If the rotor is suspended by bearings, this torque
is created by reaction forces in the bearings (acting
perpendicular to the shaft). These reaction forces turn
with the shaft as the rotor turns, at every point producing
exactly the torque needed to keep the wheel rotating
about the non-principal axis. These reaction forces can
excite the structure to which they are attached. In the
case of a car, the suspension elements can vibrate giving
an uncomfortable feel to the car occupants.
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In practical terms, the wheel will wobble. Automotive
technicians reduce the wobble to an acceptable level when
balancing the wheel by adding small weights to the inner
and outer wheel rims. Balancing is not to be confused with
wheel alignment.
Balancing machine
A balancing machine is a measuring tool used for
balancing rotating machine parts such as rotors for
electric motors, fans, turbines, disc brakes, disc drives,
propellers and pumps. The machine usually consists of two
rigid pedestals, with suspension and bearings on top
supporting a mounting platform. The unit under test is
bolted to the platform and is rotated either with a belt-,
air-, or end-drive. As the part is rotated, the vibration in
the suspension is detected with sensors and that
information is used to determine the amount of unbalance
in the part. Along with phase information, the machine
can determine how much and where to add weights to
balance the part.
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Photo of wheel balancing machine
Result of wheel unbalancing
Specifications….
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Rim Width
Rim Diameter
Max. Wheel Diameter
Max. Wheel Width
Max. Wheel Weight
Power Supply
Gross Weight
1.5 – 20 Inch
10 – 30 Inch
1067 mm
530 mm
75 kg
240 Volt
133 kg
Machine Features:
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• Easy Auto Select 2 function
• Bright & Easy to read digital display
• Auto sense sonar device for automatic detection of rim
data
• Automatic Megastick for unlimited weight positions
• Automatic start of the machine by closing the wheel
guard
• Automatic stop into the right-hand correction position
• Optimisation program to compensate the unbalance of
tyre and rim
• Durable weight tray with ample storage for wheel
weights
PROCESS OF WHEEL BALANCING:
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Remove the wheel from the vehicle.
Fix wheel on the wheel balancing machine with the help
of zinc cones, as shown in above figure.
Switch on power supply, UPS and the wheel balancing
machine.
Press start button and give little support initial rotation
to the wheel by hand.
Now wheel will start rotating with a speed of 300 rpm
aprrox.
Now press the brake pad of machine which near the base
of the machine.
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Monitor will show the result of the unbalance weight and
will show the required weight of either sides, as shown in
figure above:
Now rotate the tire manually for adjusting the weight
requiring positioning.
Now fix the required weights on inner and outer flanges.
Wheel is balanced now.
Some pics of other jobs….
Thanks…..
for your attention