Driveshafts for Industrial Applications - GWB

Technical instructions for application
Speed
Checking the critical torsional
speed
The plant or vehicle manufacturer
has to prevent the use of driveshafts
within the critical torsional
speed ranges of the drive.
Therefore, the determination of
the critical torsional speed ranges
of the drive system is required.
The values for the moment of inertia
and torsional stiffness of the
selected driveshaft can be taken
from the data sheets or be
supplied upon request.
Checking the critical bending
speed
Except for short and rigid designs,
driveshafts are flexible units
with critical bending speeds and
flexural vibrations that have to
be checked. To accomplish this,
the first and possibly second
order critical bending speeds are
important.
For safety reasons, the maximum
permissible operating speed
must be at a sufficient distance
from the critical bending speed.
The diameter is limited because
of the ratio to the shaft size.
Therefore, single driveshafts can
only be provided up to a certain
length. All installations exceeding
this limit have to be equipped with
subdivided drive lines.
For determination of the critical
bending speed, see the
following selection diagrams.
These diagrams only apply to
driveshafts that are installed with
solid bearing supports located
close to the flange.
Different installations (e.g.,
units with elastic mounting
bearing) must have lower critical
bending speeds.
Depending on the type of the
plant, excitations of second
order can cause flexible vibrations.
Please contact Dana
engineers if the deflection
angle exceeds 3° and for greater
length dimensions.
n perm. max. _~ 0,8 · n crit. [rpm]
The critical bending speed for
a particular shaft size is determined
by the length and the tube
diameter only (see diagram). For
greater length dimensions, the
tube diameter has to be increased.
41
© Spicer Gelenkwellenbau GmbH