2. Formula Student
Competition in which universities design,
build and run their vehicles with the aim of
scoring as many points as possible in the
following areas:
• Design
• Business Plan
• Cost
• Acceleration
• Skid Pan
• Sprint
• Endurance & Fuel Economy
Key PointsWhat is Formula Student
• Small engine displacement – 600cc
• Very narrow coned track
• Emphasis on agility not outright
power or speed
3. Design a centre locking wheel hub and nut system for
the Formula Student Vehicle
Brief
Exploration
• Performance Increase
• Headline Feature
• Quicker Wheel
Change-overs
Constraints
• Fit the specified
wheel
• Interface with other
components
• Meet the
requirements of the
management team
Timeframe
• Final designs to be
reviewed at the end
of January
• Manufactured by
June
4. Research - Centre Locking Systems
System 1 – Large Nut System 2 – Small Nut
• High performance
• High Cost
• Performance compromises
• Lower Cost
5. • Braking System Design – Chris
Seagrave
• Drive train Design – Ross Dewsnapp
• Team Management – Scott Thompson
– Ben Johansson
Research
Collaboration
Materials
• Stronger
• Lighter
• Cheaper
• 7075 – T6
Previous Years Hubs
PFK – 01 Front Hub Assembly
• PFK-01 - Aluminium Front hub
- Steel rear hub
• Standard bolt pattern used
7. Research
Longitudinal Loading:
• Maximum force under braking at 1.5 G
• Force per brake bobbin mount – 931 N
• Force per drive stud hole – 1397 N
Expected Loads at the Hub
Lateral Loading:
• Corner radius at 70mph – 63.7m
• Force at outside rear tyre – 2446 N
• Force required at nut – 15678 N
8. Maximum Loading
• 931N Bearing load at each brake
bobbin mount
• 1397N Bearing Load at each drive
stud hole
Development - FEA
Advantage of FEA
• Weight reduction – more critical on
rotational parts
• Stress management – Increase low
stress areas and reduce high stress
areas.
• More accurate factor of safety
• Optimised Component
9. Development – General Design
Front Hub Rear Hub
• 6 Arm design
• Same size bearings
• Main geometry fixed
• Utilising same design front and rear
• Same bearing sizes front and rear
• Brake Bobbin mount method differs
11. Development – Centre Locking Thread
• Accurate model of threads were
created at 2mm 3mm 4mm pitch
sizes
What Size Thread?
• The model configurations were
put under various simulated
loads using FEA
• The results were plotted onto a
graph for comparison
12. Development – Centre Locking Thread
Stress v Axial Load – Centre Locking Nut
FOS < 1.0
FOS < 1.5
FOS > 1.5
FOS Not
Feasible
13. Development – Tripod Journal
PFK-01 Rear
Hub
iFOUR - 11
Rear Hub
New Tripod
Journal
• Steel rear hub
• PCD 46.5mm
• Aluminium rear hub
• PCD 36mm
• 7843 N per drive face
15. Development – Bearing Selection
Deep Groove Ball Bearing Tapered Roller Bearing
• Proven set-up in previous cars
• Relatively easy to assemble
• Designed for this application
• Will improve durability and reliability
16. Development – Lock Nut
• Designed to keep the upright and bearings
in place
• Is also used as a wheel speed sensor to
allow traction control and launch control
to be utilised
• Ultimate in lightweight design, utilising
aluminium construction with metallic
paint
Design
20. Summary
• Front Hub assembly – 983g
• 32g lighter than PFK-01
• Rear hub assembly – 1092g
• 815g lighter than PFK-01
• Both hubs are of 7075-T6 aluminium construction
• Approximately 6 rotations of nut to tighten
• Total saving of over 1.6 Kg front and rear
