What are the few leaf springs and many leaf springs often mentioned in commercial vehicles? What's the difference between them?

Common leaf springs are mostly symmetrical cross-section structures. Generally, several pieces of spring steel with different lengths, different radii of curvature and equal or unequal thickness are stacked together to form an elastic beam with similar strength. Due to the different number and cross-sectional structure of spring steel leaves, we can divide them into equal cross-section multi-leaf springs and variable cross-section few-leaf springs.

So what are equal cross-section multi-leaf spring and variable cross-section spring? It is no stranger to friends who often drive trucks.

Multi-leaf spring with equal cross section;

It consists of several steel plates with different lengths and the same width and thickness. Each steel plate of a plurality of leaf springs is superimposed in an inverted triangle, with the uppermost steel plate being the longest and the lowermost steel plate being the shortest. The number of steel plates is related to the weight of the supporting bus. The thicker and shorter the steel plates, the greater the spring stiffness. Because the cross section is the same, it is also called multi-leaf spring with equal cross section. The section of leaf spring assembly is trapezoidal, with many parts and heavy weight.

Advantages and disadvantages of multi-leaf spring with equal cross section;

The structure is relatively simple and the cost is lower than other kinds of springs. However, with the increase of service time, sliding friction between steel plates will produce certain noise, and friction will also cause the deformation of springs, which will affect the smooth running of vehicles.

Small leaf spring with variable cross section;

In order to reduce the weight of the car, a new spring steel plate structure is adopted, that is, the middle section of a single spring is the thickest and the two ends are gradually thinner, instead of an equal section steel plate. The characteristics of one piece of this steel plate are equivalent to those of several pieces of steel plates with equal cross-section, so the number of leaf spring assemblies is reduced. Each leaf spring is a variable cross-section spring, and the number of leaf spring assemblies can be reduced to 2-3 pieces, and the performance meets the requirements of 6-8 pieces in the past.

The total score of this kind of leaf spring is called less leaf spring. The characteristics of few leaf springs are: the cross section of a single spring is unequal, the middle is thick and the two ends are thin; The assembly has few parts and light weight.

Advantages and disadvantages of small leaf spring with variable cross section;

Compared with the multi-leaf spring, the multi-leaf spring is about 50% lighter than the multi-leaf spring under the same stiffness (that is, the same bearing capacity), which reduces the fuel consumption and improves the ride comfort, and meets the requirements of automobile lightweight. In addition, several leaf springs are in point contact with each other, which reduces the relative friction and vibration and increases the riding comfort. However, a few leaf springs have higher requirements on the processing section technology and the manufacturing cost is higher than that of many leaf springs.