Dependent Suspensions

Earlier we discussed the working of main types of suspensions which are used in cars. In this post, we’ll discuss in depth some of dependent suspensions, which will be leaf suspension and coil suspension. These are the two major types of suspensions which are used by the automobile industry and can be found in working phase on daily roads.

Leaf Suspension:

Leaf suspension consists of simple mechanism and simple parts. It is composed of many similar metal plates or strips having the same width. These metal plates are placed over one another without any adhesive or weld, so as they are able to slide freely over one another without any external friction. Now the question comes, when do these plates slide over each other. Well, they don’t make larger displacements while sliding, but when a bump comes up, tires of the automobile push the leaf spring from edges and then this pressure from edges makes the curve formed by strips into a straight line. This conversion is only possible when lower strips will slide with the upper ones and comes into straight shape.

The leaf with the longest length, which is fastened to the supports is called Master leaf. It has bent ends in the shape of the hook in order to hold on to chassis. All strips/leaf are held together with a bolt passed through the center of these stripes. Further, these springs are classified into semi-elliptic and quarter-elliptic which will be discussed later.

Because of their high durability, these are mostly used in heavy duty vehicles like trucks.


Coiled Suspension:

The coiled suspension contains two main parts – spring and damper. Because of the presence of both, the wheel moves with correct required speed to it’s vertical position as per the demand of a bumpy road. A spring in this combination acts a normal spring like evryone must have seen. But everyone must not know the working of dampers.

Dampers used now a days consist of fluid in it’s cylinder, transfer of which helps all the mechanism work. A damper contains an outer largest cylinder fitted in which is a cylinder with smaller diameter containing a piston. This piston contains extension valves through which fluid flows from one chamber to other chamber. Since, compression of a chamber will require force and time, so this force and time will work as the stiffness of the damper. The youtube video shown below explains the whole phenomenon of a damper in much animated way.