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ISSN : 23193182, Volume-2, Issue-1, 2013
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Retractable Impact Absorbing Steering
Mubeen. N, Deepan Raj. C & Praveen Kumar. S
E-mail : [email protected],[email protected],[email protected]
Abstract - In the present scenario transportation has
become an important parameter thus it requires the
implementation of safety factors in the automobile at low
cost which can be afforded even by a common man . Our
project deals with the idea of implementing retractablesteering in the car which helps to absorb the impact
experienced by the driver during the time of collision at
low cost.
I. INTRODUCTION
The retractable energy absorbing steering column
provides safety to the driver driving the all-terrain
vehicle. This system helps to reduce the impact load
acted on the driver when the vehicle meets an accident
in the front side. The spring in the system will absorb
the load acting on it during the collision thus preventing
the driver from direct collision with the steering wheel.
This setup is placed at the steering column and thelocking mechanism provided will lock the steering
wheel when the spring completely absorbs the load.
The system is said to be retractable since after the
collision or accident the same steering system can be
used instead of replacing it. But this is not possible in
case of air bag system and collapsible steering system,
where once they are used they cannot be reused. Their
cost is also high when compared to this system what wehave designed. Hence by using this mechanism we can
able to reduce the injuries caused to the driver during
the accident with the help of less cost and it can also be
reused for an all-terrain vehicle.II. OBJECTIVE
The main objective of the project is to design the
steering mechanism which absorbs the load acted on the
steering wheel when the driver collides with it during
the accident. It also should be capable of locking thesteering wheel once it absorbed the load and should be
able to retract it whenever it is needed.
Thus the steering should able to withstand
maximum impact given by the driver but it should not
be designed such that it remains rigid when the driver
collides with the steering wheel. Whenever the impact isapplied to certain limit then the system should function
effectively by absorbing the maximum load and it
should be locked such that it never reciprocates back asit will lead to great damage to the driver. This is the
main parameter to be considered in designing the system
and fabricating it. The dimensions are chosen in such a
way that the work pieces required to machine and
assemble are easily available in around and hence its
become handy to get a new one in case if any
mistakes/errors occur during the course of our project
work.
III. CONCEPTUAL DESIGN
Figure 1 : Conceptual Design
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International Journal on Theoretical and Applied Research in Mechanical Engineering (IJTARME)
ISSN : 23193182, Volume-2, Issue-1, 2013
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The steering system provides the directional
stability to the vehicle. Along with these operations it
also performs the safety operation by absorbing the
impact load given by the driver to the steering wheel
and locks it there by providing safety to the driver. Then
the locking mechanism is used to retract the steeringsystem and it can be used further.
For designing this steering system the components
required are compression spring, hollow pipe of internal
diameter equal to the outer coil diameter of the
compression spring, the locking mechanism usually of
ratchet and pawl which provides the locking in one
direction. The designing of system is simple but it is
essential to determine the exact specification of the
spring since it plays a major role in the system. And the
location of spring should also be considered so that there
is sufficient space for the steering column to get into the
compression of the spring. Then the vital factor is thefree length of the spring which determines the maximum
load which can be absorbed by it when the driver
collides with the wheel. The locking setup is placed atthe junction of hollow pipe and the steering column such
that the releasing knob is facing outwards.
The location of the steering column along with the
steering wheel that is the angle at which it should be
placed so that it absorbs the maximum load acting on itand at which distance from the driver the steering wheel
should be placed. This is determined by using certain
calculation and placed according to it.
The design is such a way that the spring is placedinside the hollow pipe which has the base covered by
the plate so that the spring rests on it. The plate throughwhich steering column is passed is placed over the upper
side of the spring so that when the load is given to the
steering wheel it transfers the load completely to the
spring. Then the locking mechanism is placed where the
steering column is locked and the releasing pin facing
outward.
Taking all these factors into the consideration, a
design of steering mechanism is made which has the
ability to absorb the load and lock it and release it
whenever it is needed.
IV. DETAILED DESIGN
4.1 Modeling
Modeling is performed using SOLIDWORKS 2011
software.
Design has been made with the followingconsiderations as listed:
Identification of dimensions of compression
spring and locking mechanism.
Identification of suitable dimension for
hollow pipe and suitable base plates.
Base plate is fixed to the base of the hollow
pipe.
Provision for placing the spring inside thepipe.
Identification of gap between the pipe and
the spring.
Provision for covering the upper side of thespring using plate along with steering
column.
Provision for placing the locking mechanism.
Provision for adjustment of clearance
between the column and the plate.
4.2Design Calculations
Calculation of load
Car speed = 30 km/hr = 8.33 m/s
Assuming stretching distance of a seat belt =1.5 ft
Mass of the driver = 70 kg
1. v2=u
2-2as
a= (v2u
2)/2*s
a= (8.3320
2)/2*0.46
a=75.88m/s2
1. Force on driver, F=m*a
F = 70*75.88
F =5311.8548 N
Calculation of springType =
squared and grounded
Active no. of coils
(n) = 10
Total no. of coils (Nt) = 12
Coil diameter (d) = 8 mm
Mean diameter of spring (D) = 55 mm
Free length of spring (Lf) = 300 mm
Spring index, c = D/d
c = 55/8
c = 6.875
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International Journal on Theoretical and Applied Research in Mechanical Engineering (IJTARME)
ISSN : 23193182, Volume-2, Issue-1, 2013
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1. Pitch of the coil, p = free length/ (N t1)
2. P = 300/ (121)
3. P= 27.27 mm
4. Solid length, Ls= Nt*d
Ls= 12*8
Ls= 96 mm
5. Maximum deflection, Ymax= Lf -LYmax = 30096
Ymax= 204 mm
6. Maximum load, Pmax= G*D4*Ymax/8*D
3*n
Pmax = 204*.79*105*8
4/8*55
3*10
Pmax= 4959.5 N
7. Spring rate (or) stiffness, q = G*d/8*c3*n
q =0.79*105*8/8*(6.875
3)*10
q = 24.11 N/mm
4.3 Design Specifications
Spring
Free length = 300 mm
Total no. of coils = 12
Coil diameter = 8 mm
Effective spring diameter = 55 mm
Pitch of spring = 27.27 mm
Stiffness = 24.11 N/mm
Maximum defection = 204 mm
Maximum energy absorbed = 4959.5 N
Hollow pipe
Length of the pipe = 350 mm
Diameter of pipe = 65 mm
4.4 Design Of Spring
A spring is defined as an elastic machine
element, which deflects under the action of the load
and returns to its original shape when the load is
removed. The type of spring we used is the squared
and grounded type compression spring and the total
number of active coils is 10 and the number of
inactive coils is 2 and hence total number of coils is
12. The mean diameter of the spring is 55mm of
which coil diameter is 8mm. the stiffness of the
spring is 24.11N/mm and the total length of the
spring is 300mm having pitch of 27. The solid
length of the spring is 96mm and the maximum
load which the spring can withstand is 4959.5N.The design is performed in Solidworks and is
drafted to obtain a 2D sketch of the same.
Figure2 SPRING
4.5 Retractable Energy Absorbing Steering Column 3d
Assembly Model
V. WORKING PRINCIPLE
The spring is placed inside the hollow pipe so that
the base of the spring rests on the base plate in the pipe.
The upper side of the spring is covered with the help of
the plate which is connected with the steering column sothat the twisting force given to the steering wheel
directly passes to the steering column and so that spring
does not produce any effect on it. The locking
mechanism is provided at the joining of the steering
column along with the hollow pipe.
When the driver meets an accident the impact load
produced by the driver is acted on the steering wheel
which is carried on to the spring which is placed on its
way. Thus the spring will absorb the entire load acted on
it. Then the steering column moves inside the spring so
that the spring gets compressed till its free length andgets locked at some point so that it does not retract back.
Thus providing the safety to the driver by preventing
him from the sudden impact created due to the accident.
When it is needed the locked steering column can
be retracted back so that it can be used for the further
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International Journal on Theoretical and Applied Research in Mechanical Engineering (IJTARME)
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purpose. This is the main advantage of the system since
in other safety system it is not possible to use it as once
used they cannot be used further.
This mechanism can be connected to the steering
system of an all-terrain vehicle where the safety plays animportant role.
VI. FABRICATION OF CONSTRUCTION
The safety system is manufactured by making a
spring of about 300mm in length of mean coil diameter
of about 55mm which has the coil diameter of 8mm.
Then the hollow pipe of length 350mm is cut and it is
68mm in diameter. The base plates are fabricated of thesame size meeting the pipe dimension so that it covers it
completely. Then in the steering column using shaping
machine the grooves are taken such that it provides the
locking mechanism in one direction. These components
are then welded accordingly that the operations of all the
components are not affected.
Operations Used
1. Metal cutting
2. Grinding
3. Filing
4. Shaping
5. Welding
STEPS OF THE PROJECT FABRICAITON
STEP-1
The spring is designed according to the required
dimensions
STEP-2
The hollow pipe and the base plates are machined
in such a way that it completely covers the pipe.
STEP-3
The grooves are taken in the steering column rod to
provide the locking mechanism in one direction.
STEP-4
The base plate is first fixed at the base of the pipe
so that the steering column rod passes through it.
STEP-5
Then the spring is placed over it and at the top of
the spring another base plate covers it which helps totransfer the load to the spring. The joining is done using
welding.
STEP-6
The steering column rod passes through the base
plates and it has the groove at the outside of the plateand hence the locking can be done in outward
directions. Then the spring is setup for the lockingmechanism.
Fabricated steering column
Figure 4 STEERING COLUMN
VII. MACHINE TOOL USED
7.1 LATHE
The main function of the lathe is to remove metal
from a piece of work to give it the required shape and
size. This is accomplished by holding the work securely
and rigidly on the machine and then turning it against
cutting tool which will remove metal from the work in
the form of chips. To cut the material properly the toolshould be harder than the material properly the tool
should be harder than the material of the work piece,
should be rigidly held on the machine and should be fed
or progressed in a definitely way relative to work.
7.2 SHAPING MACHINE
The shaper is a reciprocating type of machine tool
intends primarily to produce flat surface. The surfaces
may be horizontal, vertical or inclined. The shaper
machine can produce any surface composed of straight
line elements and contoured surface. We used universal
shaper machine to produce groove the steering column.The cutting tool used is a square nose tool to produce
groove in the steering column. The column is clamped
on the table. The length and the position of stroke is
carefully adjusted.
7.3 ARC WELDING MACHINE
Welding is process of joining similar metals byapplication of heat with (or) without application of
pressure and addition of filter material. We used arc
welding for joining spring with the mild steel material.
Both direct current and alternating current are used for
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International Journal on Theoretical and Applied Research in Mechanical Engineering (IJTARME)
ISSN : 23193182, Volume-2, Issue-1, 2013
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electric arc welding. Both the consumable and non-
consumable electrodes are used for this welding. But in
this case we used consumable electrode. In this method
the tungsten rod is used as negative electrode and the
work being welded as positive. The arc produced
between these two electrodes heats the metal to themelting temperature.
VIII. SKILL SET LEARNT
LATHE
By using the lathe machine we learnt to
machine the work piece in terms of turning, facing
operations. The holding of work piece in the machineand fixing the tool and provide feed accordingly to
machine the work piece. Handling of machine and work
pieces and performing the various operations in the
machine has been learned.
IX. ARC WELDING
The welding of different materials using the
electrode is learnt. Providing the suitable current supply
and welding accordingly. Then we have learnt what are
the safety measures needed before and while doing theprocess. How to fix the electrodes and how to remove
those are learnt in an effective way while doing our
project.
X. SHAPING MACHINE
Shaper machine is used to cut the groove on the
steering shaft. The knowledge about how to adjustlength of stroke, type of tool to be used and how to give
feed to cut the groove is learnt.
XI. CONCLUSION
Retractable energy absorbing steering column
can be effectively used in all-terrain vehicle to provide
safety to the driver. This system is cheaper than the
other safety items like air bag and collapsible steeringcolumn and the important thing is its retractable needs
no replacement. It absorbs nearly about 5KN of the loadgiven to the driver and thereby providing safety to the
driver. Only if the load exeeds the maximum absorbtion
capacity of spring the load would be directly acthing on
the driver. However the damage to the driver is reduced.
Hence it can be used in an ATV to improve the safety of
the driver.
XII. REFERENCES
[1] Bhandari,V. B. (2010) Design of Machine
Elements,McGrawHill, third edition, pp.383-
435.
[2] Kirpal Singh (2011) Automobile Engineering-volume1,standard publishers, pp.236-240.
[3] PSG design data(2011), kalaikathir achchagam.
[4] www.physicsforum.net
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