1. Compare with 9 layers leaf spring, useing 4 or 5 leaf spring is more advanced and scientific. Better structure provides better shock resistance and pressure resistance. At the same time, the thickness of each leaf is thicker and the weight is heavier.

2. Leaf spring is the most widely used elastic element in automobile suspension. It is an elastic beam with approximately equal strength composed of several alloy spring sheets of equal width but unequal length (thickness can be equal or unequal).

3. When the leaf spring is installed in the automobile suspension and the vertical load is positive, each spring plate is deformed and has the trend of upward arch bending. At this time, the axle and frame are close to each other. When the axle and the frame are far away from each other, the positive vertical load and deformation of the leaf spring will gradually decrease, and sometimes even reverse. The main piece's rolling ear is severely stressed and is a weak point. In order to improve the stress condition of the main piece's rolling ear, the end of the second piece is often bent into a rolling ear and wrapped outside the main piece's rolling ear, which is called wrapping ear. In order to make it possible for each piece to slide relatively during elastic deformation, a large gap is left between the roll ear of the main piece and the wrap ear of the second piece. Both ends of leaf springs in some suspensions are not made into rolling ears, but other support connection methods, such as rubber support pads, are adopted.