# The modification theory of the metal spring

Generally speaking, soft springs provide better comfort and maintain better track record when traveling through more rugged roads. But in the general road surface, but will cause the suspension system large up and down swing, affecting the control. In cars equipped with good aerodynamic components, soft springs can cause high changes in speed, resulting in different handling characteristics at low speedand and high speed. Tell us about the theory of spring modification.

The spring of the metal spring suspension system is most commonly used in circle springs because of its ease of production, high performance efficiency and low price. The physical definition of a spring is to store energy, when we apply a fixed force to the spring, it will produce deformation, when we remove the force then the spring will have a tendency to restore the original shape, but the spring in the rebound of the magnitude of the soup will often exceed its original length, until there is friction resistance to slow the spring rebound after the cause of the free shock soup, which slows the work of free spring shock soup is usually the task of the shock absorber.

The general spring is called a “linear spring”, that is, when the spring is forced, its compression deformation is to follow the physics of the “Huke’s law”: F – KX, where in which F is force, K is the elastic coefficient, X is the amount of deformation. For example, a linear spring is subjected to a force of 40Kg will cause 1cm compression, after each increase of 40Kg force 1 cm will certainly increase the amount of compression. In fact, there are other pressures present in the suspended spring, even when the spring is fully extended, the spring will still be subjected to pressure so that the spring itself is fixed to the car.

In the traditional spring, shock cylinder type suspension design, the spring plays to support the body and absorb uneven road surface and other forces on the impact of the tire, and the so-called other forces here include acceleration, deceleration, braking, turning and other forces caused by the spring. What is more important is to maintain the continuous contact between the tire and the road surface during the elimination of vibration and maintain the track of the car. Improving the tyre’s contact with the road surface is our primary consideration in improving handling.

The main function of the spring is to maintain the comfort of the car and keep the tire in complete contact with the ground, using the wrong spring will cause a negative impact on the quality of the car and handling. Imagine if the spring is completely stiff, the suspension system will not work. When the car jumps on uneven road surfaces, the tires will leave the ground completely, and if this happens at acceleration, braking or turning, the car will lose track. If the spring is soft, it is very comfortable with the “sitting bottom” situation, that is, the hanging trip exhausted. If the sitting bottom condition occurs at the bend can be regarded as the spring’s elastic coefficient becomes infinite (no compressed space), the body will produce an immediate weight shift, resulting in the loss of trace.

If the car has a long shock-absorbing journey, then it may be possible to avoid the “sitting bottom” situation, but the relative body will also become very high, and a high body means a high body center of gravity, the body center of gravity of the body of the high and low on the handling performance has a decisive impact, so too soft shock absorbent will lead to handling obstacles.

If the road surface is absolutely flat, then we don’t need springs and suspension systems. If the road surface is more rugged then a soft spring is required to ensure that the tire is in contact with the road surface, while the spring travel must also increase. The hardness of the spring is determined by the degree of ruggedness of the road, the more rugged the softer the spring, but the softer is a key issue, usually this requires the accumulation of experience, but also the factory and the team of important issues.