TORSION BAR SUSPENSION SYSTEM IN AUTOMOBILE | CONSTRUCTION AND WORKING OF TORSION BAR SUSPENSION SYSTEM

INTRODUCTION:

         A torsion bar is a type of suspension system that is usually used in vehicles such as cars, trucks and vans. A suspension system is a significant and acute element of a vehicle’s design. Irrespective of the design, all suspension systems do the same functions. They keep the tires in contact with the surface of the road, upkeep the weight of a vehicle and absorb the forces produced by the movement and motion of the vehicle.

  

CONSTRUCTION OF A TORSION BAR:

          Torsion bars are basically metal bars that perform the role of a spring. At one end, the bar is fixed rigidly in place to the chassis of a vehicle. The last end of the bar may be fastened to the axle, suspension arm, or a spindle, depending on the vehicle’s design. For instance a vehicle travels alongside the road, the forces made by the motion of the vehicle produce torque on the bar, which turns it along its axis.

       Counteracting the torque is the fact that the torsion bar obviously wants to resist the twisting effect and return to its normal state. By doing so, the suspension supplies a level of resistance to the forces generated by the movement of the vehicle. This resistance is the basic principle behind a torsion bar suspension system.

WORKING OF TORSION BAR:

            Torsion bars use the twisting properties of a steel bar to offer coil-spring-like functions. One end of a bar is fixed rigidly to the vehicle frame. The further end is fastened to a wishbone, which acts like a lever that travels perpendicular to the torsion bar. When the wheel hits at a stone or projections, vertical motion is shifted to the wishbone and then, through the levering act, to the torsion bar. The torsion bar then twists sideways its axis to offer the spring force. European car manufacturers used this system widely, as did Packard and Chrysler in the United States, through the 1950s and 1960s.

ADVANAGES:

          In this system there are several key advantages. The design of the torsion bar suspension takes up less area than other suspension systems. This makes the vehicle designers to create a more spacious passenger compartment. The elevation of the bars can also be varied more easily than other suspension systems. They are also extremely durable and habitually have a long service life.

DISADVANTAGES:

       There are also several disadvantages of torsion bar suspensions. The main disadvantage is that these bars generally do not offer what is known as a progressive spring rate. Generally in suspensions with a progressive spring, the coils of the spring are spaced at dissimilar distances from each other. This permits the suspension system to aids braking, firm steering and handling, although providing for a smooth and comfortable journey. Vehicles with torsion bars are repeatedly tuned to either provide a more firm driving experience at the expense of ride smoothness, or a smoother ride at the expense of the vehicle’s handling quality.

RECENT:

          Torsion bar suspension systems were once relatively common in passenger vehicles, but today are used mainly for the suspension systems of trucks and sport utility vehicles. Some famous automobiles that used this type of suspension were the original Porsche 356, Volkswagen Beetle, Porsche 911 models that utilized an air-cooled engine, and significantly of the Chrysler line-up of cars from the late 1950s through the late 1980s.