An inboard braking system is an automobile technology where in the disc brakes are mounted on the chassis or to the gearbox of the vehicle, rather than directly on the wheel hubs. The main advantages are a reduction in the unsprung weight of the wheel hubs, as this no longer includes the brake discs and calipers; also, braking torque applies directly to the chassis or the gear box , rather than being taken through the suspension arms. Inboard brakes are fitted to a driven axle of the car, as they require a drive shaft to link the wheel to the brake. Most have thus been used for rear-wheel drive cars, although four-wheel drive and some front-wheel drives have also used them.

1. GURU NANAK INSTITUTIONS TECHNICAL CAMPUS
MOHAMAD ABDUL ( 14WJ1A03H2 )
DESIGN AND FABRICATION OFSINGLE REDUCTION GEARBOX WITH
INBOARD BRAKING
Under the guidance of
V.ANANDA MOHAN

2. DESIGN AND LAYOUT OF POWERTRAIN
This report will go into further depths of actual engineering analysis and formulation of our team’s drive train. The
contents describe the formal equations that describe our concept generation as well as the layouts and explanation of
our final system. Below we have generated a gear ratio from our given constraints with reasonable assumptions.
Assumptions and variables:
Wheel Diameter : 23 inches
Total Weight : 232 Kgs
Slope : 30 degrees
Reduction Ratio : 10.4
Efficiency of CVT : 88% (From manufacturer of CVTech CVT)
Goal
A) Torque:
In the incline or steep situations of the track, the required torque should be produced. As we assumed the incline
to be 30 deg (max) with inspection of previous year’s course. In order to complete the incline, the force on the two
wheels will need to be greater than the component of force of gravity along the incline.

3. FREE BODY DIAGRAM OF OUR VEHICLE :

4. B) Speed
We considered 4.2 sec to finish 100 foot course as per the top teams result in previous year’s competition.
Distance = Max Velocity x Time / 2
Max Velocity = Distance x 2 / Time = 100 foot x 2 / 4.2 sec = 52.25 km/h
Therefore 60 km/h is the goal for the max speed to obtain.
Analysis of CVT system:
The analysis of Continuous Variable Transmission provides the gear ratios that would be required to obtain the
goals introduced above. Though the analysis need some assumptions such as wheel diameter and total weight
should be chosen appropriately which are mentioned above.
CVT High ratio = 0.45:1
CVT Low ratio = 3: 1
• Start rpm for CVT is 800 rpm and high speed ratio occur at 3600 rpm, ratio varies linearly within 800 rpm and 3600
rpm.

6. GEAR BOX :
Specifications Value
Gear Reduction 10.4:1
Kerb weight 6.0 Kg
Lubrication System Splash
Mounting Flat Base
Input to Output Centre Distance 160 mm
Gear No. of Tooth Pitch Diameter Module
Input 18 36 2
Intermediate 1 48 96 2
Intermediate 2 18 36 2
Output 70 140 2
GEAR PARAMETERS:

7. All dimensions are in mm

8. OUTPUT SHAFT DESIGN:
All dimensions are in mm

9. OUTLINE DRAFT OF GEAR BOX:
SIDE VIEW All dimensions are in mm

10. REAR VIEW
All dimensions are in mm

11. Virtual model of assembly

12. • An inboard braking system is an automobile technology where in
the disc brakes are mounted on the chassis or to the gearbox of the
vehicle, rather than directly on the wheel hubs.
• The main advantages are a reduction in the unsprung weight of the
wheel hubs, as this no longer includes the brake discs and calipers;
also, braking torque applies directly to the chassis or the gear box ,
rather than being taken through the suspension arms.
• Inboard brakes are fitted to a driven axle of the car, as they require a
drive shaft to link the wheel to the brake. Most have thus been used
for rear-wheel drive cars, although four-wheel drive and some front-
wheel drives have also used them.
INBOARD BRAKING:

13. Hydraulic brakes work on the principle of Pascal’s law which states that :
“Pressure at a point in a fluid is equal in all directions in space”.
According to this law when pressure is applied on a fluid it travels equally in all directions
so that uniform braking action is applied on all four wheels.
PRINCIPLES OF HYDRAULIC BRAKING:

14. Brake Pedal Clamped.
Brake Fluid Pressurized in Master
cylinder.
Pressurized Fluid is travel through hose
pipes.
Thus, this pressurized fluid press brake
pad against Brake Rotor.
Due to Friction between Brake Pad and
Brake rotor action is performed.
Working Of Hydraulic Brake:
DOT 4 230 °C 155 °C
Dry boiling
point
Wet boiling
point
DOT 4 is Hygroscopic and will
absorb water from the atmosphere.

15. WORKING OF TANDEM MASTER CYLINDER:
STAGE:1
STAGE:2
STAGE:3 STAGE:4

16. Calipers are of two types:
FIXED CALIPERS:
• They have Pistons on both side of the disc.
• They may be 2 or 4 pistons per caliper.
➢This type of caliper requires higher hydraulic pressure.
➢The caliper that is fixed and doesnot slide .

17. FLOATING CALIPERS:
➢ Applies pressure to two pads on opposite sides of the rotor.
➢ Friction material is exposed to air.
➢ Much more common.
➢ Easier to Work with.
➢ On “inboard” side of caliper.

18. • Torque At Rotor
Tr = Ff * Reff
Tr = Torque at Rotor (Nm)
Reff = Effective radius of rotor (m)
Tr = 1677.9*0.085
= 142.62 Nm
• Stopping Distance:
▪ For a vehicle experiencing a linear deceleration, the stopping distance of
the vehicle can be calculated as follows:
Sd=Vv^2 / (2 * av)
where,
Sd = Stopping distance of the vehicle.
Vv= 39 kmph = 10.83m/s
Sd = (10.83)^2 / 2 * 22.64
= 2.59m
• Pedal Force
𝐹𝑏𝑝=𝐹𝑑 × 𝐿2/𝐿1
Assuming 𝐹𝑑= 200 N
Where
𝐹𝑏𝑝= Total Pedal Force (N)
𝐹𝑑= Total Driver Effort (N)
L2= Pedal Pad to Pivot Length
L1= Pivot to Master Cylinder Push Rod
Calculations:
Disc Brake has been modelled with the help of
SOLID WORKS software. The solid model of disc brake is shown
in the figures.

19. CONSIDERATIONS:
Following considerations are chosen for the material of DISC
used .
❑ Young’s modulus=2x105N/m2
❑ Poissions ratio=0.3
❑ Pressure=492N/m2
❑ Temperature=300℃
Material used:
ASTM G50 – Grey castiron

20. Design Specification
of rotor
Modeling
Meshing
Tangential Force
Between Pad and Rotor
Brake Torque
Calculation
Braking Distance
Calculation
Heat generated
Through Braking
Flow chart of Design and Analysis
PROCEDURE:
EXPLODED VIEW OF WHEEL ASSEMBLY

21. COMPONENTS USED:
Finally from the above calculations the components used in the vehicle are
Tandem master
cylinder
DOT – 4
Brake Fluid Steel braided
brake lines
Front Disc Rear Disc
APACHE RTR 180
DIAMETER :200MM
DIAMETER :180MM
Fixed caliper
(Pulsar 220F)
Floating caliper
(Apache RTR Front)
REAR caliper mount to Gear box
And rear disc with hub which is welded to CV joint

22. FABRICATION:

23. COMPLETE SPECIFICATIONS :
Gear CVT Ratio Gear Box
Reduction
Overall Reduction Tractive Force
Low Gear 3:1 10.4:1 39.90 1993.32 N
High Gear 0.43:1 10.4:1 11.09 556.66 N
Acceleration 6.2 m/s2
Acceleration time(100m) 4.2 sec
Gradability 59 %
Max. Torque 482.67 N-m
Briggs & Stratton 10HP OHV INTEK
Displacement : 305cc
Max Power : 705 KW
Max Torque : 19 N-m
NVH considerations
▪ Use of muffler to reduce noise from the engine.
▪ Elimination of extra clutch mechanical linkages which produces vibrations.
▪ Calculation of engine distance from the front and rear shockers to the driver’s
position to eliminate the vibrations from the engine for driver comfort.

24. INSTALLATION TO THE VEHICLE:

25. TESTING VIDEO:

26. BRAKE TEST AT THE EVENT:

27. CONCLUSION:
SAE BAJA is an excellent activity for students to apply what they learned in their four years
of engineering to solving a practical problem. They need to plan and execute all phases of
the product development and production cycles. They also need to demonstrate economic
viability of the project by doing cost analysis and marketing presentations.
We realised that, it was not a vehicle dynamics that we had to deal with, but also team
dynamics. Lessons were learned in building a successful team and importance of team
work, individual accountability and communications.
Our standings
Cost event : 12th position
Endurance : 18th position
Hoping for better standings in future events .

28. REFERENCES:
[1] Bajasaeindia.com(2018).[online] retrived from: http://bajasaeindia.com
[2] Khurmi, R.S & Gupta, J.K – 2003. Theory of Machines. S.Chand & Co.
[3] Khurmi, R.S & Gupta, J.K – 1996. Text Book of machine design.
[4] PSG college of Design data book Kalakhathir.Coimbatore 2010.
[5] Shigley, J.E(1956). Machine Design. New York: McGraw-Hill.
[6] Swapnil R. Abhang, D.P Bhaskar, International journal of engineering trends and
technology (IJETT), “Design analysis of disc brake”, Volume 8 Number 4-Feb 2014.

29. THANK YOU