Possibilities of Coil Springs and Fiber-Reinforced
Suspension Parts

Possibilities of Coil Springs and Fiber-Reinforced
Suspension Parts

Possibilities of Coil Springs and Fiber-Reinforced
Suspension Parts

As early as over 400 years ago, the first helical compression
springs (coil springs) were already used for wheel
suspensions of a wagon body, and at the very latest since
the invention of the wheel suspension strut (McPherson),
they have represented the best spring design for the
vertical dynamics of passenger cars. They took over suspension
functions and because of their advantages regarding
weight and installation space, replaced leaf springs almost
completely. The necessary suspension arms to carry the coil
springs may be regarded as a disadvantage, but their design
enables exceptionally good road holding and safety.
Springs will be deformed elastically and during this
process, they take up potential energy, which will be
released when relieved. They will have to live up to
such duties also during repeated and dynamic loads and considerable deforming processes. For this reason also, steel
continues to be an ideal material to make springs.
Over the past few years, resource-saving weight reduction
has assumed growing importance. Assuming that the
weight of a smaller middle class car was kept constant, the
weight of a chassis support spring was reduced by about
55% since 1992 (Figure 1). Such weight reductions were
brought about by higher loads, underpinned by optimized
manufacturing technologies and new types of steel, without
any reductions in robustness.
One example of the developments in manufacturing technology
is the high performance process (HPP) developed by
the Mubea company, as a result of which the load-bearing
strength of helical compression springs was increased by
more than 10%. This method was first introduced in 2003,
and it has been used as the global benchmark since 2004.
Moreover, in future, there will be increasing demands
by car builders as regards CO
reductions, lower vehicle
weights, and a reduction of unsuspended sections and the
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robustness of springs, particularly as affected by corrosion.
This means that optimum use of materials employed will
play a decisive role, underpinned by efficient design. In
addition to that, alternative materials, such as composite
materials, may be increasingly important when used for
suspension purposes.

Joerg Neubrand