Chassis Design Index

Chassis Design Principles and Analysis

List of Chapters Foreword  Authors’ Preace Preace Origins and Objectives  Acknowledgements  Acknowledgements List o Plates List o Figures List o Tables 1. Maurice Olley–His Life and Times 1.1. Reminiscences 1.2. Chronology–Maurice Chronology–Maurice Olley 1.3. Holyhead Road 1.4. Olley’s Associates 1.5. Introduction to the Monographs 1.6. Suspension (General Discussion) 2. Tires and Steady-State Cornering–Slip Angle Effects (Primary) 2.1. Introduction Part A: Simplied Tire Models 2.2. Tires Eect o Slip Angle on Lateral Force Mathematical Representation Representation o Lateral Force vs. Slip Angle Further Study o Parabola Notes on the Olley Tire Model Note on Wheel and Tire Part B: Bicycle Model Examples 2.3. Steady-State Steady-State Turns (General Discussion) Introduction Steady-State Turns Camber Steer–In a Parallel Independent Front Suspension (IFS) Roll Steer Changes in Steer Angle at the Front Wheels 2.4. Calculating Steady-State Steering Characteristics (Bicycle Model) Introduction Measuring Steering Characteristics Examples Conventional Constant Radius/Variable Radius/Variable Speed Skid Pad Test The “Innite Skid Pad” (Testing at Constant Speed)

Fixed Steering Angle Part C: Four-Wheel Four-Wheel Model Examples 2.5. Lateral Weight Transer Eect (Wheel Pair) Introduction Distribution o the Roll Moment (about the Ground) Roll Moment Eects Roll Moment Eects–Analysis Based on the Layout o Figure 2.30 and Notation o Figure 2.29 2.6. Calculating Steady-State Steady-State Steering Characteristics with Lateral Load Transer Transer Distribution (LLTD) Introduction Tires Summary o Steady-State Equations Some Variations Tire Lateral Forces 2.7. Traction Eects Introduction Rolling Resistance Combined Longitudinal and Lateral Tire Force Power Required 2.8. Neutral Steer Point and Static Margin Introduction Neutral Steer Point 2.9. Swing Axle Introduction Approximate Approximate Figuring o Swing Axle Roll Moments Swing Axle “De-Stabilizing” the Swing Axle 2.10. Summary o Steady-State Steady-State Steering (Primary Eects) 2.11. Summary o Calculations in Sections 2.4 through 2.9 Section 2.4 Section 2.5 Section 2.6 Section 2.7 Section 2.8 Section 2.9

Chassis Design Principles and Analysis 3. Steady-State Cornering–Steer Effects (Secondary) 3.1. Introduction Note on Understeer/Oversteer as Measured in Skid Pad Tests 3.2. Roll Eects Inclined Roll Axis 3.3. Wheel Control (Rear Axle) Rear Axle Hotchkiss Rear Axle Torque Tube Rear Axle (and Panhard Rod) Four-Link Rear Axle Three-Link and Panhard Rod Oset Torque Arm Swing Axle Geometry 3.4. Wheel Control (Front Suspensions and Steering) Roll Steer o Front Wheels Front Axle Forward Steering Geometry in Roll Lea Spring Geometry Front Axle Center Point Independent Front Suspension Wishbone Suspension Rear Steering Linkage Forward Steering Linkage 3.5. Understeer and Oversteer Eects, Front and Rear 3.6. Torque Steer 3.7. Lateral Defection Steer Flexibility o Steering Linkage Timing o Lateral Defection Steer Rear-Steer Eects 3.8. Straight Running 3.9. Suspension Geometry Eects Toe-In and Camber Camber-Change Variations (Wishbone Suspension) Caster Kingpin Angle Wheelght 3.10. Eect o Road Surace 3.11. Wind Handling Introduction Yaw Damping Due to the Tires Path o Car Factors Aecting Wind Handling 3.12. Summary

4. Transient Cornering 4.1. Introduction 4.2. Checkerboard Test (Stonex) 4.3. Qualitative Transient Description (Schilling) Turn without Roll–No Understeer or Oversteer Turn with Roll 4.4. Linear Analysis 4.5. CAL Results (Segel) 4.6. Turn Entry Transient (Olley) 4.7. Moment o Inertia and Wheelbase Introduction Estimated k2 /ab in Plan View 4.8. Steering when Moving Forward Time Response Response Plots or a Modern Car Steering when Moving Forward, Steady State 4.9. Steering when Moving in Reverse Comments on Steering in Forward and Reverse Time Response in Reverse 4.10. Boat Steering and Truck in Reverse Boat Steering Truck in Reverse 4.11. Note on Ackermann ℓ  /R Approximation 4.12. Summary 5. Ride 5.1. 5.2. 5.3. 5.4. 5.5.

5.6. 5.7. 5.8.

5.9. 5.10. 5.11. 5.12. 5.13.

Introduction Dry Friction Fluid Damping Steel Springs: Work Storage Analysis Work Stored in Springs Round Wire Helical Spring in Compression, or Torsion Rod Toggles and Sel-Leveling Two Degrees o Freedom The Rowell and Guest Treatment Spring Center O CG o Sprung Mass Pitch Stability Oscillation Centers Actual Ride Frequencies Height o Oscillation Centers and Sprung CG Additional Material on the Two-Degree-o-Freedom Ride Model Unsprung Weight Independent Suspension

Chassis Design Principles and Analysis 5.14. 5.15.

Multiple Suspension Summary

6. Oscillations of the Unsprung 6.1. Introduction 6.2. Shimmy Dynamics and Its Cures Center-Point Steering Kingpin in the Wheel Plane Drag-Link Springs Shimmy Shackle Compensated Tie Rods Independent Suspension Mechanisms 6.3. Wheelght Introduction Steering Gear Resonance Wheelght Cures Eect on Wheelght (Schilling, “Handling Factors,” 1938) 6.4. Caster Wobble (Olley) Case Study–Chevrolet with Dubonnet IFS Road Speed Road Surace Engine Mount Summary–Caster Wobble 6.5. Wheel Hop Introduction Damping o the Sprung and Unsprung Masses Harmonic Wheel Hop Absorbers Frequency o Wheel Hop Shock Absorbers 6.6. Fore and At Forces 6.7. Washboard Roads 6.8. Brake Hop 6.9. Reverse Power Hop Note on Reverse Power Hop (Oset Torque Arm) 6.10. Axle Tramp “Sculling Action” 6.11. Crane-Simplex Linkage 6.12. Damping o a Swing Axle 6.13. Note on Raised Roll Center without Swing Axle 6.14. Handling Factors (Report by Robert Schilling, GMPG, 1938) Waddle and Side Chuck Wheelhouse Clearance Tire Scrub Scrub Damping

6.15.

Rear Axle Side Shake Camber Change or Swing Arm Action Roll Cambering Summary

7. Suspension Linkages 7.1. Introduction 7.2. Front Suspension with No Osets (First Approximation) Camber Change 7.3. Steering Linkage (without Anti-Dive) 7.4. Eect o Anti-Dive on Steering Linkage Layout 7.5. Wheel Motions with Arm-Planes at an  Angle to the Transverse Plane 7.6. Greater Accuracy (Allowance or Osets) Camber (Inclination) Change ( γ )  Tread Change (One Wheel) 7.7. Comparison Example–Front Suspension without and with Osets 7.8. Link Suspension Rear Axle 7.9. Rear Axle Linkage with Osets 7.10. Ride Rates and Wheel Rates 7.11. Camber Thrust 7.12. Toe-In–Swing Axle with Diagonal Pivot 7.13. Wheel Rates–Wishbone Suspension 7.14. Tread [Track] Change Radius 7.15. Eect o Camber Change on Wheel Rate 7.16. Vertical Rate o Arm and Torsion Spring 7.17. Position o Springs 7.18. Summary 8. Roll, Roll Moments and Skew Rates 8.1. Introduction 8.2. The Roll Axis Axle Independent without Tread [Track] Change Independent with Tread Change Swing Axle 8.3. Intermediate Designs o Independent Suspension 8.4. De Dion Axles 8.5. Skew Rates [Warp] 8.6. Longitudinal Interconnection– Compensated Suspension Total Roll Rate or Compensated Suspension Skew Rate 8.7. Roll Stability Scale Eects

Chassis Design Principles and Analysis

8.8. 8.9.

Roll Stabilizer Roll Axis Measurement Summary

9. Fore and Aft Forces 9.1. Introduction 9.2. Maximum Traction Front Drive Grades 9.3. Brake Distribution 9.4. Brake Dive 9.5. Anti-Dive Geometry 9.6. Power Squat 9.7. Mercedes Single-Joint Swing Arm 9.8. Vehicles with Axles Controlled by Lea Springs Wind-Up o Unsymmetrical Spring Note on Wind-Up Stiness o Lea Springs 9.9. Inclination o Lea Springs 9.10. Anti-Dive Front Wishbone Suspension 9.11. Sudden Brake Application 9.12. Summary

 Appendix A

Slip Angle Sign Conventions A.1 Introduction A.2 SAE Sign Convention A.3 Olley’s Sign Convention A.4 Summary

 Appendix B Fiala/Radt Nondimensional Tire Representation B.1 Introduction B.2 Derivation B.3 Advantages o Tire Nondimensionalization  Appendix C

Technical Papers by Olley–Summaries and Reviews

 Appendix D

Olley Correspondence

 Appendix E

Balloon Tires and Front Wheel Suspension

 Appendix F

Sense of Direction

 Appendix G

Development of the Flat Ride

Index 10. Leaf Springs–Combined Suspension Spring  About the Authors and Linkage 10.1. Introduction 10.2. Circular Bending e 10.3. Parallel Cantilever 10.4. Theoretical Single Lea 10.5. Figuring a Lea Spring a 10.6. Cantilever Spring 10.7. Equal Leaves and Equal Spacing 10.8. Combined Spring Rate (with “Unbalanced” Springs) 10.9. Eective Torque Arm 10.10. Roll Rates 10.11. Shackle Eects–Symmetrical and Unsymmetrical Springs With Symmetrical Lea Springs Shackle Eects, Unsymmetrical A Springs 10.12. Spring Testing B 10.13. Summary

b

c

d f

C D

D 0 C

B

A