Design of Rubber Spring for Replacement of Torsion Bar on a Three Wheeler Rear Suspension

The three wheeler vehicle segment in India has an important bearing in both passenger and load carrier segment upto 0.5 tones. Durability requirements under specified loadings and good ride comfort are prime parameters in a competitive segment. This segment is highly sensitive to cost and warranty.

To meet the above requirements and add more value to the vehicles, the rear suspension of three wheelers which is traditionally a torsion bar and trailing arm type is redesigned with a multilobe rubber spring. The rubber spring profile to meet the desired stiffness characteristics is designed and evaluated through finite element analysis.

The paper presents the study on the design of the Multilobe rubber spring through the simulation of the hyper-elastic and nonlinear contact behavior of rubber. The profile is optimized through analysis and a correlation is obtained on a prototype test. The paper also highlights the modifications required on the vehicle to transform the suspension and the tests done to evaluate the same.

The implementation of this has unfolded several benefits for the customer in terms of value. It has helped in elimination of the torsion bar. Using finite element analysis the organization has gained by reducing the cost and time for development of such a rubber spring without having to go to the molder to make several parts iteratively and test the same.