Installation
conditions
While rotating, the universal joint has a sinuslike,
fluctuating angular speed depending on the deflection
angle. As described in detail in the chapter ,,General
fundamental theory", this system-linked fault can be
offset for a driving line equipped with two or more
joints by choosing special joint arrangements.
When dimensioning the drive or the auxlliarv drive, the following
rules must be observed in practice:
Angle conditions of the universal shaft
1. Shaft with two joints
"Z-arrangement"
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"W-arrangement"
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 The deflection angles of the joints must be
equal:   =
This rule is also applicable to front view and top view
pictures.
The joint yokes of the connecting shaft must
be in one plane.
All three shafts must be in one plane.
Note: All these three rules must be
observed simultaneously.
A joint arrangement in two planes must be avoided if
possible. lt is always given when the driving and driven
shafts are not in the same plane. If this arrangement is
unavoidable and rigid on the installation side, this
,,fault" can be kinematically compensated by a joint
misalignment.
For the resulting deflection angles the following
equations are applicable:
2. Shaft with three joints
In cases where greater distances between units have to be
bridged, the universal shaft must be supported by an
additional, mostly elastic, bearing.
In order to keep the remaining irregularity in the drive
(joint 3) as small as possible, the sum of all
irregulanties of the individualjoints must be equal to or
almost equal to zero.
(See "Kinematics of Hooke's joints")
The signs must be entered according to the following sign
rule. Here the sign rule is:
 for the joint position
 for the joint position
The remaining non-uniformity if any should not be greater
than:
 The minimization of the remaining
non-uniformity can also be achieved by the so-called
equivalent deflection angle
 erfolgen.
 The sign rule is also applicable
here.
The equivalent deflection angle
= 3° is the equivalent deflection angle of
a single joint which corresponds with a degree of non-uniformity
U = 0,0027.
3. Shafts with several joints
In case of an arrangement with more than three joints
proceed as described above.
General recommendations for lorry drives:
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For fast-running
drive shafts observe the instructions on the
transverse whirling speeds for installation
length.
(See "Influence of speed
and deflection angle") |
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Choose small
resulting deflection angles for the main drive
range:
(See also (n x β)perm. "Influence of speed
and deflection angle") |
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Minimize the
angular difference between the joints and the
remaining inequaltity
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If these recommendations are not observed, one must
reckon with vibrations and noises and with a reduced
driving comfort as well as with a reduced lifetime of the
units.
Deflection of joints in two planes
If a "classic shaft arrangement" cannot be
realized and the joint deflection cannot be changed, this
can be offset by turning the joints. For this shaft
arrangement the Installation rule that the resulting
deflections of the joints must be equal remains in force,
i.e.
 Plane 1 formed by the driving
shaft 1 and the connecting shaft 2 on the one hand and
Plane II formed by the connecting shaft 2 and the driven
shaft 3 on the other hand form the angle
 which is offset by turning the joints
correspondingly.
The torsion angle
is determined as follows:
The rotation direction results ifom the side view, i.e.
joint 1 must be turned to plane 1 by the angle
.
The shaft must be mounted according to these statements
and this before a possible balancing.
This position of the joints must be marked with arrows.
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DANA
Commercial Drive Shafts Catalogue 
