n automotive engineering and other
technical areas there are many appli-
cations in which a compressive load is
applied to a spring element. The
springs are designed to exert a restor-
ing force whenever required. Due to the
wide range of application areas the he-
lical compression spring (commonly re-
ferred to as a compression spring) is
not the only spring element used to
generate a restoring force. The most
common spring types, which according
to certain basic conditions can generate
optimum performance in the assembly,
will be described in more detail below.
Basically, we differentiate between
static load – e.g. for the coupling of
components when tolerances need to
be compensated and forces transmitted
–
and dynamic load. In the latter case,
the spring simultaneously acts as a
force transmission element and an ab-
sorptive medium for any vibrations
which occur. For instance, compression
springs in valve assemblies with up to
500
million load cycles during an en-
gineʼs service life or nozzle holder
springs for fuel injection must deliver
the highest possible quality. This also
applies to clutch and gearbox springs,
or to spring packs in automatic gear-
boxes.
Spring shapes
Depending on the specified assembly
space, the generating line of helical
compression springs can have a cus-
tom design. The simplest version is
without doubt the cylindrical helical
compression spring. This spring should
be used whenever possible, as it offers
the best price-performance ratio. If the
available space is unsuitable for a cylin-
drical spring, it is possible to choose
from conical, beehive, concave and
convex compression springs. The de-
sired shape is created during the wind-
ing process at the coiling machine. De-
pending on the shape of the generating
line subsequent processes, such as
spring end grinding, creating an outer
or inner bevel, etc., must be adapted to
the respective spring shape. Further-
more, every imaginable generating line
shape can be produced.
Besides the flexible design of the gen-
erating line, the variable pitch or spac-
ing between the coils is a key factor.
Standard helical compression springs
boast a quasi linear spring characteris-
tic along a possibly long spring deflec-
tion.
In contrast, a linear spring characteris-
tic would result in the malfunctioning of
dynamically loaded helical compression
springs, as excitations above the
springʼs natural frequency could not be
damped, leading to excessive dynamic
stress in the spring. Special progressive
spring characteristics are therefore de-
veloped to enhance dynamic behaviour.
Every imaginable pitch can be realised.
Material and wire diameter for
compression springs
For reasons of economic efficiency,
round wire is the most commonly used
wire shape for compression springs.
However, due to the increasingly small-
er assembly spaces (weight saving,
consumption reduction, etc.) it is often
necessary to use other types of wire. If
it is imperative to reduce the assembly
2
MECHANICAL ENGINEERING – MANAGEMENT –
TECHNOLOGY & PRODUCT DEVELOPMENT
–
NEWS AND INFORMATION
I
SCHERDEL compression-lo
are ideal problem solvers
RESEARCH & DEVELOPMENT
‘
Spring Designer’ ensures the perfect spring desig
Staff profile
Weʼd like to introduce staff mem-
bers who will act as your contact
if required.
Dipl.-Ing. (FH) Hans-Martin Ram-
bold, Division Manager
As a specialist for compression
springs and compression-loaded
spring systems, Hans-Martin
Rambold is the ideal contact at
SCHERDEL. Hans-Martin also
wrote the two specialist articles in
this edition of SCHERDEL news.
His professional career within the
Group began in the quality man-
agement field in 1990. After grad-
uating in mechanical engineering
from the University of Applied Sci-
ences in Coburg, he relocated to
the SCHERDEL factory in Leuten-
dorf in 1994 and became its Qual-
ity Manager. Seven years later he
was appointed Technical Manager
at the newly founded SCHERDEL
Druckfederntechnik Röslau GmbH
&
Co. KG (DFTR).
Hans-Martin is currently a
Division Manager in the develop-
ment sector ʻPowertrain and
Auxiliariesʼ.
He is a man of many talents and
steps into the role of the chief pi-
lot of a King-Air turbo-prop for
SCHERDEL business trips. Hans-
Martin Rambold is married with
two sons, who, incidentally, are
both employed at SCHERDEL.
His hobbies include playing in the
SCHERDEL hornblower group,
skiing, cycling and windsurfing.
(
dk)
