Introduction to Sona
Koyo Steering Systems Ltd.
1
COMPANY PROFILE
Fig 1.1 sona steering
Sona Koyo Steering System Ltd(SKSSL), is a flagship company of Sona group. Established in
1985 through a technical and financial collaboration with JTEKT Corporation, Japan (formally
known as Koyo Seiko Co Ltd), the largest producer of passenger vehicles steering system in
world. The company today is the largest manufacturer of steering system India, catering to
passenger cars, utility vehicles and light commercial vehicles. Valued at $800mn currently, the
group has presence across locations in India ,three in Germany and one plant in the US. We
visited Sona Koyo Steering System Ltd’s mother plant in Gurgaon to understand the
manufacturing philosophy on the steering majors.
The Sona Group was founded in 1987 to manufacture components for the automotive industry.
Today it is a USD 800 million multi-national – with over 16 plants across India, 3 in Germany
and 1 in the USA. The group also has a strategic position in Fuji Autotec, Europe - which has
subsidiaries in Brazil, France, Sweden and the Czech Republic. Starting out as a “Manufacture to
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Print” organisation, the group today boasts having created its own IPR particularly in the areas of
power steering for off highway applications and precision forging.
The Sona Group has engineering capabilities in the areas of machining and assembly, precision
forging, cold & hot forging and heat treatment. The Group’s range of products primarily consists
of steering and driveline components for the automotive OEM segment namely passenger cars,
utility vehicles, commercial vehicles and specialty vehicles.
The Group is committed to expansion of its products range and clientele by continuous
investment in research and development. SONA is drawing upon the strength of its joint venture
partners which include JTEKT Corporation, Japan and Mitsubishi Materials Co., Japan to
upgrade it's systems, skills and production values to offer its customers contemporary and high
quality products.
The Group boasts the world’s largest precision forging enterprise, India’s largest steering
systems manufacturer – recognized in 1997, by the World Economic Forum as a top–performing
Global Growth Company; a recipient of the prestigious Deming Award in 2003 it received the
TPM Excellence award in 2007.
The company's customers include major vehicle manufacturers, such as General Motors,
Hyundai, Mahindra & Mahindra, Mahindra-Renault, Maruti Suzuki, Tata Motors, and Toyota. It
exports its steerage system components to the U.S., Europe, and Japan through its network of
overseas joint-venture partners and its own increasing global footprint.
Fig 1.2 company layout
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PLANT DETAILS
GURGAON PLANT
Plant location
38/6, Delhi-Jaipur Road, Gurgaon (Haryana), India, 38 Km from
New Delhi, 22 Km from Delhi Airport, 10 Km from Maruti Udyog
Ltd.
Total Site Area
56,970 sq. m
Total Floor Area
14,125 sq. m
CHENNAI PLANT
Total Site Area
56,970 sq. m
Total Floor Area
10,890 sq. m
DHARUHERA PLANT
Total Site Area
20,117 sq. m
Total Floor Area
9,255 sq. m
SANAND PLANT
Total Site Area
16,200 sq. m
Total Floor Area
2,639 sq. m
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Production Commenced -
56970 m2
Plant –1
R&P Steering Gear
Steering Column
2933 m2
Plant-2
RBS Steering Gear
Axle and Prop Shaft, Diff. Assy
R&P Power Steering
5363 m2
Case differential, Collapsible
column, Uj,
Utilities, Stores etc.
2213 m2
Total Site
Plant –3
Plant-4
Others
Certification
QS 9000, ISO 14001, TS16949
Subsidiary companies of Sona Groups are:
1) JTEKT SONA AUTOMOTIVE INDIA LTD.
2) SONA FUJI KIKO AUTOMATIVE INDIA Ltd.
3) SONA STAMPING Ltd.
4) SONA KOYO STEERING SYSTEM Ltd.
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1265 m2
1330 m2
CUSTOMERS
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PRODUCTS
PLANT-1
1)
RPS Assembly Manual (TOYOTA)
2)
RPS Assembly Manual (MARUTI 800)
3)
Collapsible Column (SAFARI)
4)
Collapsible Column (YE-2R)
5)
Collapsible Column (MODEL-A)
6)
Collapsible Column (SCORPIO)
PLANT-2
1)
Shaft Propeller Assembly
2)
RBS Assembly (OMNI,GYPSY)
3)
Case Differential Assembly (TELCO)
4)
Case Differential Assembly (OMNI)
5)
Case Differential Assembly (YE-2R)
6)
Axle Assembly (OMNI,GYPSY)
7)
Sector Shaft Assembly
PLANT-3
1)
Hydraulic Power Steering(all models)
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PLANT-4
1)
Case Differential (SWIFT)
2)
Collapsible Column (MARUTI 800)
3)
Column Assembly (ALTO)
4)
IMV Column (INNOVA)
5)
Column Assembly (OMNI)
6)
Column Assembly (SCORPIO)
Sona koyo working philoshopy
SONA KOYO respects the dignity of human beings at all levels. In the matter of employment, it
believes in the concept of equality in caste, religious, creed., race, sex and nationality.
Employees selection shall be merit based and made on basis of proven ability of the
incumbents(s).
SONA KOYO endeavors to provide equal opportunity to all and one in the matter of internal
promotion. Only the right person for the right job however, shall be promoted.
SONA KOYO is conscious of fact that the growth an d progress of its employees and the
company is inter –dependent, hence the concept of all round development of its team members
shall be of prime importance.
SONA KOYO encourages meaningful participation of its team members to achieve the
organizational goals and objectives.
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SONA KOYO constantly endeavors to establish and promotes clean and safe working
environment where it team members may work happily and drive joy and pleasure.
SONA KOYO shall encourage and promote sports and such other cultural activities, which may
be useful in building the moral values and national character of honest, discipline and integrity
among its team member.
SONA KOYO as a good cooperate citizen shall like to participate in the community
development and welfare programs in its surroundings areas so as to develop understanding and
generate goodwill amongst the inhabitancy of local society.
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PRODUCTS AND TECHNOLOGY
Sona Koyo Steering System Ltd primarily works on different types of steering systems for
different applications.
Two modules on which Sona Koyo Steering System Ltd works are:I.
Rack and Pinion steering(RPS)
II.
Hydraulic power steering (HPS)
Main customers of Sona Koyo Steering System Ltd are:I.
II.
III.
Mahindra and Mahindra
Maruti Suzuki
Tata motors
and many others.
Fig 2.1 workshop
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For Hydraulic power steering (HPS) SUV from Mahindra and Mahindra, XUV are latest
business acquisition.
Company presently works on a wide range of steering columns including tilt, tilt/telescoping,
collapsible and rigid type and these are in huge demand in Indian automobile market.
Fig 2.2 Column electric power steering unit
Fig 2.3 Manual steering columns
Recently company focus on his new products, customers and product diversification as well as
new engineering capabilities.
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On the basis of some new engineering capabilities company introduced some new concepts of
steering systems:
Column Electric power steering (CEPS).

Electric power assisted module (EPAM).
are new technology developed recently.
EPAM is in huge demand and also being supplied to a company in USA mainly for recreational
vehicles. System is also used in tractors. EPAM is a combination of mechanical and electrical
system and company has patent for this product. Main benefits of EPAM system is lower torque
requirement for movement, which result in fuel saving.
Fig 2.4 assembly line
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STEERING
The objective of steering system is to provide a reliable method for controlling the direction of
vehicle that is capable of withstanding the high stress placed on it. There are no direct
requirements for the type of steering method used or how sharp you must be able to turn.
However there is a safety specification that requires all tie rods to be protected from a frontal
impact.
Fig 3.1 sample model
Steering is the term applied to the collection of components, linkages, etc. which will allow
a vessel(ship, boat) or vehicle (car, motorcycle, bicycle) to follow the desired course. An
exception is the case of rail transport by which rail tracks combined together with railroad
switches (and also known as 'points' in British English) provide the steering function.
The steering system allows the driver to control the direction of vehicle travel. This is made
possible by the linkages that connect the steering wheel to the steer able wheels and tires. The
steering system may be either manual or power. The steering system has components:
The steering wheel and steering shaft that transmit the driver’s movement to the pitman
arm.
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
The pitman arm that increases the mechanical advantage while changing the rotary
motion of the steering wheel to liner motion.

The steering linkage that carries the liner motion to the steering arms.
The next factor that takes into consideration deals with the response from the road. The response
from the road must be optimum such that the driver gets the suitable feel of the road but at the
sometime, the handling due to cornering is not affected.
PURPOSE OF STEERING SYSTEMS
The purpose of the steering system is to allow the driver to control the direction of the vehicle by
turning the front wheels. Together with the suspension system, it plays an important role in
ensuring easy, comfortable driving all the way from the low speed range to the high-speed
ranges.
A good and efficient steering system has to ensure the following:
1. Excellent Maneuverability: When the car is cornering on a narrow, twisting road, the
steering system must be able to turn the front wheels sharply yet easily and smoothly.
2. Proper Steering Effort: If nothing is done to prevent it, steering effort will be greater
when the car is stopped and will decrease as the speed of the car increases. Therefore, in
order to obtain easier steering and better feel of the road, the steering should be made
lighter at low speeds and heavier at high speeds.
3. Smooth Recovery: While the car is turning, the driver must hole the steering wheel
firmly. After the turn is completed, however, recovery- that is, the return of the wheels to
the straight-ahead position- should occur smoothly as the driver relaxes the force with
which he is turning the steering wheel.
4. Minimum transmission of Shock from Road Surface: Loss of steering wheel control
and transmission of kickback due to road surface must not occur.
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RACK AND PINION (RPS)
In the rack and pinion type steering, the steering main shaft has a steering pinion at the lower
end. This steering pinion meshes with the steering rack. As the steering wheel is turned, the
steering pinion rotates to move the steering rack to the right or left.
fig 4.1 Assembly of rack and pinion
The movement of the steering track is transmitted to the knuckle arms via the steering rack ends
and the tie rod ends.
The rack and pinion gear set does the two things:I.
It converts the rotational motion of the steering wheel into the liner motion needed to turn
the wheel.
II.
It provides a gear reduction, making it easy to turn the wheel.
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Fig 4.2 differential axel
Presently company accounts for 30% supply of rack and pinion CEPS steering system. In
Gurgaon plant approx units are manufactured per day and almost unit are made at Dharuhea
plant. Entire system is developed in house by Sona Koyo Steering system Ltd engineers. Spare
parts such as pinion and housing are also manufactured here which are then assembled with the
remaining system.
Fig 4.3 rack and pinion assembly line
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Manufacturing assembly of rack and pinion steering system
The rack and pinion manual steering assembly line in the plant is multimodal in nature. This line
is responsible for producing steering systems for seven different models of Maruti Suzuki India
(MSIL). Manufacturing is on the principle of Pokaoke.

Poka-Yoke is a Japanese technique where ‘poka’ means mistake and ‘Yoke’ means
avoid.
The present capacity of this line is 53 units per hour. This Japanese technique plays a very
important role, because manufacturing of this system has assembly up to 27 parts and even a
short error could result in a part failure. The process of line is not very complicated, if any step is
going wrong during the process, the assembly line automatically get stop and signals the problem
area through a light system. And when the indicated problem gets resolved the line get start
automatically. Usage of the Poka-Yoke technique also helps the line workers to ensure that the
assembly parts do not get mixed when steering system for multiple models are being
manufactured at the same time.
During assembly process, a very special care is taken for safety parameters that may be affecting
the human body in a direct or indirect way. For example, if any operator doesn’t torque the
steering appropriately it gets result in steering failure, when the vehicle is in motion. In order to
make zero error, the line is fixed with an electronic torque zone, which is also based on pokaYoke. Incase if any operator is missing out , the zone detects it and top the conveyer belt and get
resume only when the problem has been detected. And then the assembly checked for the other
fitting parameters. These assemblies are direct on Line (DOL) parts, means they are sent directly
to the assembly line in installation ready state.
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Fig 4.4 Rack and pinion manual steering assembly line
Some other driveline products made by Sona Koyo are:I.
Axle assemblies
II.
Case differential.
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Fig 4.5 Axle assembly line
These assemblies manufactured by the company are supplied to many automobile companies.
SKSSL manufactured about 650 units of rear axle daily. This plant also manufactured
Recirculating Ball Bearing (RBS) assemblies. RBS steering systems are mainly used in light
duty vehicles.
Testing
SKSSL has a test track to check the performance of any product after its completion. Only after
properly checked and verify by engineers products are sent to market. Track has various
surfaces; steering system is installed in car and then tested on the track. In this text engineers
checked the sound, vibration and durability on a particular system.
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Fig 4.6 testing track
Company has adopted several techniques to reduce its manufacturing costs like:
They have their own furnace and paint shop.

They perusing a strategy of maximum possible in house capabilities.

The company has started making its own manufacturing machines too.
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Fig 4.7 furnace shop
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HYDRAULIC POWER STEERING
Gurgaon has finery machinery system and they adopt fine process for manufacturing of the
hydraulic power steering. Present customers are Fiat, M&M, Maruti Suzuki, Toyota and Tata
motors.
Hydraulic power steering
Hydraulic steering mainly consists of a pump, fluid lines and a piston. System works in a way
that when steering is operated, only about 10% of force is needed from the driver and rest is
supplied by the hydraulic pump.
Manufacturing assembly of hydraulic power steering system
Assembly process starts with a cylinder tube and pinion housing. First step is to wash a
component to remove any foreign particles. After this, tow road seals are pressed into the
component to prevent any fluid leakage and bearing pressing for pinion support. Post this the
rack bar is being installed, where it converts the rotary motion of the pinion into linear motion,
allowing sideways movement of the wheel.
The rack bar is installed with the pinion housing and cylinder tube. Care is taken during the
insertion of rack bar because even a minor deviation can result in damage to the rod. Then
hydraulic fluid may be leak, which result I failure of the component. The next step is to match
the pinion with the teeth of the rack bar, after which the inlet/outlet fluid tubes are installed I the
assembly. These tubes make the hydraulic fluid to circulate through the system. Then a special
formatted white colored fluid is sprayed on to the seals of these tubes. This white layer spots any
leakage in the tubes.
The assembly is than placed in an air testing machine, where air circulates through the system at
pressure ranging between (7-8) kg/cm2. If any leakage is spot, component is taken off the
assembly line and sent to the further appropriate procedure section. In the next process a machine
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creates a clearance of 50-100 microns in the rack bar and pinion. In the absence of this clearance,
the steering is uncomfortably tight to operator.
Fig 5.1 HPS assembly line
Testing
In further step the assembly is passed through a endurance testing machine, which detects any
leakage in the system. If any defect is spotted component is taken off from the assembly and sent
for the inspection. A load and torque testing machine that applies torque and load which is pre
determined to the steering. This process check if any variation in the torque and load readings in
the system.
Following the endurance test, the assembly is passed to a performance testing machine, which
checks the performance of pinion. The machine can detect any sound I the steering, through
which operator allows spotting the defect. In the end of the assembly line, the hydraulic fluid is
removed as they are delivered to the OEMs in a dry state.
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Fig 5.2 Endurance testing machine
The steering is then assembled with the rod gear and tie rods and sent to the final station. At this
point, line operators check if there are any dimensional irregularities or not. If any spotted, the
assembly is sent back to the corrective station. In case of everything going well, the product is
sent for packing and logistic.
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OUTLOOK OF COMPANY
The strategy of expanding outside India seems to be on track for the company. The focus is on
new products development and engineering. Then company further diversifies its product
portfolio, thereby preventing its risks. Business in India too continues to grow at a steady pace as
the company adding new names regularly to its customer base.
Fig 6.1 outlook
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CONCLUSION
Working at the Sona Koyo Steering System Ltd. Gurgaon assembly plant has been a great
learning experience. The training has given me a chance to practically apply a lot of concepts
that I had learnt in my B-tech mechanical and automation course.
The work has taught me that one’s fundamentals must be strong in order to implement
something. Working on actual automobiles, chassis has given me a far more clear understanding
of what is actually manufactured and how the whole process occurs. The process of how a
product starts from its drawing then finally implemented as a mass production vehicle is clear to
me.
Quality is a major factor in any project. And in cars, where it is directly related to the safety of its
occupants, it becomes a far major, concern. To check quality, we need to understand the
problems first and research on them. Then only the defects can be minimized.
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REFERENCE
1)
http://www.sonagroup.com/index.php?option=com_content&view=article&id=100&I
temid=218&lang=en
2)
https://en.wikipedia.org/wiki/Steering_system
3)
http://www.cdxetextbook.com/steersusp/steer/princ/steersys.html
4)
Notes provided by mentor.
5)
Practical information given by mentor.
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