Systematic Approach for Static Steering Effort Reduction through Linkages Optimization in Small Commercial Vehicles (SCV)

Abstract

The steering system design of a vehicle is of utmost importance as it not only acts as an interface between the driver and the entire vehicle but also is one of the key vehicle sub system which accounts for vehicle overall performance including vehicle handling and stability. With the recent infrastructure development and changes been witnessed in doing commercial vehicle business to hub and spoke and to door to door logistics delivery are expecting improved vehicle performance particularly in small and light commercial vehicles segments (SCV and LCV) where the business demands are more for the movement of vehicle in narrow city lanes and sharp corners. Also, now driver comfort is considered one of the key factors before purchasing any commercial vehicle. Thus, having power steering in SCV’s and LCV’s has not only become a mandate but also the vehicle steering system performance should be such that the driver is easily able to maneuver the vehicle in narrow city lanes and corners. Through this paper a methodology has been derived wherein factors contributing for achieving static lock to lock maneuverability in a power steering vehicle are analyzed without overdesigning the hydraulic power assistance of the vehicle. The approach mainly focuses on LH/RH symmetric hydraulic pressure build up in the system by critically designing the steering system linkages hard points such as drop arm length, drop arm SAP angle, steer arm length, track rod arm’s length. Also, this study ensures that the derived hard points not only enhances hydraulic assistance in the steering system but also ensures vehicle to have least turning circle diameter (TCD) and enhanced tire life by having least Ackermann error.

Keywords: Static Steering Effort Optimization, Recirculating Type Ball Type Steering System, Kingpin Torque, Straight Ahead Position (SAP) Angle, Pressure Relief Valve (PRV), Linkage Optimization, Turning Circle Diameter (TCD), Small Commercial Vehicle (SCV), Steering Geometry, Vehicle Dynamics, and Ackermann Error