650:342 Analysis And Design of Custom Hydraulic Clutch Pedal

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650342Analysis And Design of Custom Hydraulic
Clutch Pedal

• Zachariah John
• Henry Helfman
• Bernadette Bautista

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Previous Pedal Design
Uses rod and crank system Requires adjustment
to compensate clutch wear Has 6 major high wear
surfaces Mechanical geometry (pivot points)
limits applications
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Non-Hydraulic Clutch Linkage Systems
Bell Crank
Cable Clutch System
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Hydraulic Clutch System Advantages

• Easy to mount master cylinder on flat surface
  behind pedal (firewall)
• Few wear items which have much lower wear than
  other clutch linkage systems
• Piston/Cylinder assemblies automatically
  compensate for clutch surface wear and need no
  adjustment

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Improved Design Goals
1. Make a system which allows installation of
hydraulic clutch pedal when standard parts are
unavailable 2. Use mostly production or
aftermarket parts and keep custom manufactured
parts to a minimum to be cost effective and
practical 3. Use simple system that can be
implemented to any vehicles firewall section
(space permitting)
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Model Information

• The improved pedal is a modified bell crank unit
  retrofitted to operate a Hydraulic Master
  Cylinder.
• An actuation arm which joins the pedal to the
  master cylinder rod is welded to the original
  pedal.
• The pedal has a weight of 1.869 lb (4.8359E-03
  lbm).
• Galvanized Annealed Steel is the material used in
  the pedal.

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Material Properties for Galvanized Annealed Steel

• Modulus of Elasticitypsi 2.7993E07
• Density lbm/in3 7.5148E-04
• Poisson's Ratio 0.2900
• Thermal Expansion
• Coefficient 1/degF 9.8889E-06

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FEA Loads Constraints

• Constrained and loaded with 20 lb applied load to
  lower base pedal surface
• Analyzed with Ansys

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Analysis Specifications

• Applied Loads
• Type Entity X Y
• Force lb Area 91.56
  8.010
• Force lb Area -14.14
  -14.14
• Reaction Forces lb
• X Y Z
• -76.867 -22.103 -4.12794E-04
• Total Moment lb-in
• X Y Z
• 7.4646 -85.318 98.502

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Equivalent Stress, Maximum Principal Stress and
Critical Point
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Fatigue Test

• The Critical Stress (SC) on the clutch pedal is
  24.750 ksi.
• 108 Cycle Strength (endurance limit)
• Sn Sn' CL CG CS Sn' 0.5SU
• 25.48125 ksi. SU 151 ksi
• CL 1
• CG
  0.75
• CS
  0.4
• Since SC lt Sn fatigue life is infinite.

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Corrosion Wear Analysis

• Pedal surfaces are painted
• Every frictional surface is lightly greased and
  insulated with a plastic bushing so anodic
  corrosion of the material is irrelevant.
• Rod is in contact with the pedal, which gives way
  to adhesive wear.
• Wear W ?K?H??F?S K10-3
• 5.074410-8 in.3 H 452.832103
  psi.
• 8.315410-4 mm.3 F 91.9134 lb.
• S
  0.25 in.

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Disposal

• Pedal assembly will most likely be salvaged at
  end of vehicles useful life or recycled with the
  rest of the vehicle