anneal steel strip Suspension Leaf Spring

Specifications

A leaf spring is a simple form of spring commonly used for the suspension in wheeled vehicles. Originally called a laminated or carriage spring, and sometimes referred to as a semi-elliptical spring or cart spring, it is one of the oldest forms of springing, dating back to medieval times. A leaf spring takes the form of a slender arc-shaped length of spring steel of rectangular cross-section. The center of the arc provides location for the axle, while tie holes are provided at either end for attaching to the vehicle body. For very heavy vehicles, a leaf spring can be made from several leaves stacked on top of each other in several layers, often with progressively shorter leaves. Leaf springs can serve locating and to some extent damping as well as springing functions. While the interleaf friction provides a damping action, it is not well controlled and results in stiction in the motion of the suspension. For this reason manufacturers have experimented with mono-leaf springs. A leaf spring can either be attached directly to the frame at both ends or attached directly at one end, usually the front, with the other end attached through a shackle, a short swinging arm. The shackle takes up the tendency of the leaf spring to elongate when compressed and thus makes for softer springiness. Some springs terminated in a concave end, called a spoon end (seldom used now), to carry a swivelling member. Characteristics 1. The leaf spring acts as a linkage for holding the axle in position and thus separate linkage are not necessary. It makes the construction of the suspension simple and strong. 2. As the positioning of the axle is carried out by the leaf springs so it makes it disadvantageous to use soft springs i.e. a spring with low spring constant. 3. Therefore, this type of suspension does not provide good riding comfort. The inter-leaf friction between the leaf springs affects the riding comfort. 4. Acceleration and braking torque cause wind-up and vibration. Also wind-up causes rear-end squat and nose-diving. Manufacturing process Multi-leaf springs are made as follows: Shearing of flat bar Center hole punching / Drilling End Heating process forming (hot & cold process) Eye Forming / Wrapper Forming Diamond cutting / end trimming / width cutting / end tapering End punching / end grooving / end bending / end forging / eye grinding Center hole punching / Drilling / nibbing Heat Treatment Heating Camber forming Quenching Tempering Surface preparation Shot peening / stress peening Painting Eye bush preparation process Eye reaming / eye boring Bush insertion Bush reaming Assemble Presetting & load testing Paint touch-up Marking & packing

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