Redesign and manufacturability assessment of a telescopic shock absorber system to enhance performance on uneven potholed roads

Abstract

The shock absorber system is part of a vehicle’s suspension system. It controls consistent tyre contact with the road surface and damping of road induced. Shock absorber systems in most light vehicles are produced with set damping forces, tailored to Original Equipment Manufacturer (OEM) weight assumptions and even road conditions. However, in many parts of the world especially countries with poor roads such as Uganda, actual driving conditions differ. Roads are often un-even and potholed and this leads to increased wheel travel and excessive stress on shock Absorber components resulting in low service life. With the goal of improving ride comfort, stability, and durability over uneven potholed roads, this study re-designed a telescopic shock absorber system for a light passenger car (Toyota Wish) addressing these challenges. A study was made to ascertain the technical capabilities required for the local manufacture of the redesigned coil spring and damper. Design parameters were obtained from computations using derived scientific formulas and equations. While SolidWorks aided in Computational fluid dynamics (CFD) and finite element analysis (FEA), Shim Restackor studied damping properties to validate the new shock absorber system design. The simulation results have shown that the duo, 6-active turn Chromium-vanadium Coil Spring of wire diameter 14.4mm and free length 342mm with spring rate of 33.7 ×10³N/m and a damper of 150mm stroke, peak force of 3.12KN (Rebound) and 1.58KN(Compression) with a tuned valve configuration system and damping coefficient of 0.35 are capable of handling and tolerating more weight, absorbing sudden impacts while maintaining sufficient ride height and stability. A high damping efficiency was achieved vindicated by compression chamber pressure rise from an initial 0.8 MPa gas pre-charge to approximately 2.5 MPa at full compression stroke, and over 3.75 MPa. Furthermore, the manufacturing Cost modelling showed that at ≥ 8000 units/ month, the hybrid system undercuts fully imported units by ≈ >20%, which percentage can be increased given government intervention through policy amendments and funding. The redesigned shock absorber is expected to give smoother rides, lower vibrations, and a service life of over 5 years, thereby improving vehicle safety, stability, durability, and overall affordability.