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REVERSE GEAR MECHANISM IN TWO WHEELER FOR
HANDICAPPED PEOPLE
Sreehari K U
UG Student, Department of Mechanical Engineering,
MGM College of Engineering and Technology,
Pampakuda, Kerala, India.
Sibin Sunny
UG Student, Department of Mechanical Engineering,
MGM College of Engineering and Technology,
Pampakuda, Kerala, India.
Joshua A J
UG Student, Department of Mechanical Engineering,
MGM College of Engineering and Technology,
Pampakuda, Kerala, India.
Swaran Joseph
UG Student, Department of Mechanical Engineering,
MGM College of Engineering and Technology,
Pampakuda, Kerala, India.
Febin M Suresh
Assistant Professor, Department of Mechanical Engineering,
MGM College of Engineering and Technology,
Pampakuda, Kerala, India.
Abstract At times when the front wheel goes into a trench it is very
difficult to take the wheel from parking. Even normal people
face much problem to take the vehicle out of the parking. In
case of handicapped people who drive two wheelers with
extra support wheels, face much problem to take the vehicle
out of parking by pushing the vehicle with leg like normal
people do. In order to take the vehicle out of parking, they
need others help or they should do it alone.
As a help to them we have created a gearbox which could
perform forward motion as well as reverse motion. It includes
the selection of a suitable reverse gear mechanism for two
wheelers. The fabrication process deals with designing
suitable gear wheels, and assembling it in the gearbox which
provides easy assembly and manufacturing at low cost. This
paper details the design and fabrication of a mechanism that
can provide reverse motion in two wheelers.
Keywords: gear box, reverse gear mechanism, gear wheel.
Introduction Disability in humans may be caused during birth which may
be of physical, cognitive, mental, emotional and
developmental. The disability in humans may be a physical
disability, sensory disability, and vision impairment, olfactory
and gustatory impairment. According to a survey conducted
by the National sample survey Organization conducted during
the period of July–December 2002, it was found that the
number of people having locomotion disability alone was
found to be 23,557 in the rural areas and 14099 in the urban
areas.
In human life transportation is playing very important role
from ancient time, due to transportation and communication
facilities we say that, world is coming closer and closer. Day
by day new vehicles with variety of models are coming into
market. Normal person i.e. person without any disability can
avail this vehicles easily. But in our society the number of
disabled persons is also considerable, some of them born with
disability, some get disabled due to accidents (road,
workplace, natural calamities, etc.), large number of persons
get disabled due to war activities and due to many other
factors. Depending upon the severity of disability, the
disabled persons can use the transportation facilities; persons
with lesser disability can use the facilities as it is for normal
persons, some persons are able to use the vehicles with little
bit modifications like retrofitted bikes and cars. There are
some utilities like wheelchairs, tricycles which are used by the
disabled persons. In some cases the disability is so severe that
person can’t move from one place to other place without help.
The persons with hand and leg disability are able to travel but
they are unable to use the vehicles for normal persons as it is.
So the vehicles are modified (customized vehicles) to make
them accessible to the disabled persons.
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 14, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com
Page 1 of 4
Objective
The objective of this work is to identify suitable
method of reverse gear mechanism for the usage of
physically challenged people, provide more facilities
on two-wheeler to make more comfortable and
independent too.
Design of gear box was mostly the result of the
requirement specified by medical practitioners who
always insisted on transportation needs hence it
always lacked engineering/ergonomic approach. This
work intends to use the terminology for the
technology for the benefit of challenged people and
hence, two-wheeler with side car one of the largely
used product by these people
Nowadays, transformations are inseparable part of
the human life. Normal person can travel easily by
means of transportation such as bicycles, bikes, cars,
public transports etc. But for physically challenged
persons, travelling is not easy. Depending upon the
disability physically challenged person can avail
travelling such as tricycle, wheelchair, customized
vehicle like car, bike, buses etc.
But these means, off transportation are not easily
accessible for physically challenged persons due to
some difficulties. This project discusses these means
of transportation for physically challenged people.
Material selection
Table 1: Mechanical properties of EN19
Properties Metric
Tensile strength 655 MPa
Yield strength 415 MPa
Bulk modulus 140 GPa
Shear stress 165 MPa
Elastic modulus 200 GPa
Poisson’s ratio 0.28
The materials used for the manufacture of gears depend upon
the strength and service conditions like wear, noise etc. The
gears may be manufactured from metallic or non-metallic
materials. The metallic gears with cut teeth are commercially
obtainable in cast iron, steel and bronze.
The material of the bevel gear used is EN19 also called AISI
4140. AISI 4140 steel is a low alloy steel containing
chromium, molybdenum, and manganese. It is widely used
across numerous industries and is an excellent material choice
due to its toughness, high wear resistance, high fatigue
strength, and abrasion and impact resistance.
Clutch dog Outboard motors nearly all use a simple dog clutch type
mechanism for connecting the propeller to the engine. The
clutch dog is splined to the propeller shaft and allowed to
move fore and aft sufficiently to engage the teeth machined on
the side faces of forward and reverse gears. Both gears spin
freely on the propeller shaft and are rotating while ever the
engine is running. The dog clutch is moved to engage the
desired motion by a cross pin and shift rod inside the hollow
propeller shaft.
Figure 1: Typical outboard dog clutch shift system.
Design of gear and shaft Design of gear
As the rotation from engine needs to be transmitted to
perpendicular shaft we require pinion and bevel gears.
We selected a pinion of 13 teeth which has a diameter of 4.0
cm.
Teeth, T1 = 13
Diameter, D1 = 4.0 cm
Rotations per minute, N1 = 5100
We require shaft rotation of 3400 times per minute,
So, N2 = 3400
Hence the requirement of designing a bevel gear.
Using gear ratio formula:
D1/D2 = N2/N1 = T1 /T2
ie, 4/D2 = 3400/5100 = 13 /T2
D2 = (5100/3400) * 4.0
= 7.0 cm
T2 = (5100/3400) * 13 = 23
So a bevel gear of 7.0 cm diameter with 23 teeth is required.
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 14, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com
Page 2 of 4
Design of shaft
Length of shaft = (clearance space + double the thickness of
gear + distance between side frame to
wheel + thickness of frame)
= ( 3 + 3.5 + 3 + 10 )
= 19.5 cm
1 Kg = 1000g = 9.81 N
1 g = 9.81 * 10-3 N
Weight of bevel gear = 210g = 2.06 N
Weight of wheel = 3000 g = 29.5 N
Figure 2: Free body diagram.
RA + RB = (2.06 +2.06 + 29.5) = 33.62 N
(RA * 9.5) + (-2.06 * 6.5) + (-2.06 * 3) + (29.5 * 10) = 0
(9.5RA – 13.39 – 6.18 + 295) = 0
Therefore, RA = -28.9 N
RB = 62.52 N
Shear force diagram
Figure 3: Shear force diagram
Bending moment diagram
Figure 4: Bending moment diagram
Maximum bending moment = (29.5 * 10) = 295 Ncm.
M = 295 Ncm = 295*10-2 Nm.
P = (2π*N*T)/60
55000 = (2*3.14*5400*T)/60
ie, T = 97.31 Nm.
T equivalent = (M2 + T2)1/2 = (2.952 + 97.312)1/2
= 97.35 Nm
We selected material EN19, which has a shear stress in the
range 150 MPa to 180 MPa.
Here we took the shear stress as 165 MPa.
= 16 T/ πd3
165*106 = (16*97.35)/(3.14*d3)
Solving we get,
d = 14.43*10-3m
= 14.43 mm
Standardizing the diameter with reference to data hand book
by K.Mahadevan, design of shaft – page no: 57 – Table 3.5(a).
Thus, d = 16 mm.
3D modeling
Figure 5: Top view
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 14, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com
Page 3 of 4
Figure 6: ISO view
Working
The rotation from the engine is transmitted to the rear wheel
as in vehicles, from there it is transmitted to the shaft carrying
the clutch dog assembly through the shaft. On pushing the
clutch dog to either sides the direction of rotation changes.
This rotation is further transmitted to the shaft to which tyre
are connected with the help of bevel gear by central shaft
carrying the pinions. Thus both forward and backward motion
based on positioning of dog clutch is possible.
Conclusion The design and fabrication of this mechanism was a
successful one. We used an outboard engine, and alterations
were made which could be manufactured in industrial level in
future. It didn’t face any kind of difficulties in producing the
required reverse motion. Implementing this mechanism to
handicapped vehicle would be a greater help to them. This
work has provided us an excellent opportunity and experience,
to use our limited knowledge. We gained a lot of practical
knowledge regarding, planning, purchasing, assembling and
machining while doing this work. We are proud that we have
completed the work with the limited time successfully. The
reverse mechanism is working well with satisfactory
conditions.
Future Scope of Work
This mechanism can be made more flexible such that this
could make reverse motion possible in all two wheelers on
easy and immediate assembly. Thus could be implemented in
large application levels.
References
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 14, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com
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