rod head bearing assembly - service news
Post on 28-Jun-2015
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Rod head bearing assembly
Service News Customer Support
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For over 30 years this specially developed bearing con-
cept has been successfully operating in Loesche mills.
Fig. 1 demonstrates the operational principle of the
spring system and the direction of the forces within it.
As the Loesche mills became bigger, the safety factor
for the bearings (Fig. 2) was also increased to improve
the reliability of the machines.
Our engineers are constantly working to improve the
productivity of Loesche mills and to modernise their
technology. In the past, bearing damage occurred in
the rod heads of some of the larger mills. These failures
were due to wear on the inner and outer races of the
spherical roller bearing installed there. Loesche and the
bearing manufacturer, SKF, worked together to analyse
the cause of such damage.
• The investigation report shows that there is no
overloading involved but that a combination of
dynamic loads and inadequate lubrication lead
to micro-pitting within the loadzone.
This micro-pitting is known in other fi elds of operation
and is called “False-Brinelling”. The investigation
showed that a signifi cant improvement in mill reliability
could be achieved by redesigning the bearing and
changing of the location of the loadzone.
These ideas were confi rmed in a computer simulation
of the spherical roller bearing at the SKF laboratory in
the Netherlands.
Rod head bearing assembly
Loadzoneon top
Fig. 2: Original design of the rod head bearing assembly
Fig. 1: Schematic of the hydropneumatic spring system
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The new design (Fig. 3):
• 2 cylindrical roller bearings are now installed in the side cheeks of the fork of the rocker arm, where the movement takes place.
• The loadzone has moved to the bottom.
• The grease fl ows by gravity into the contact area.
This bearing concept will be applied in future to all mills from Module 30 upwards, as well as to the clinker and slag mills.
Advantage:
This concept allows for a better distribution of the loads
as well as a reduction in the dynamic forces experi-
enced by the bearing, thus almost eliminating the risk
of a breakage of the rod head!
Recommendations:
Our Customer Support offers you a conversion kit
comprising of the following components for the modi-
fi cation of your Loesche mill:
• Plain spherical bearing
• Cylindrical roller bearings
• Pin
• Rod head
• Set of installation parts
• Set of turned components
N.B.:
For a modifi cation to the original Module 30 it is neces-
sary to increase the seating bore diameter in the fork.
This rework can be accomplished with the rocker arm
in a workshop or “in Situ” using a special machine
which can be supplied by Loesche.
Contact:
If you need further information or have a specifi c ques-
tion, then contact our Customer Support team by
E-Mail at
customer-support@loesche.de
Force
Pressure
Movement
Loadzone at the bottom
Fig. 3: New design of the rod head bearing assembly
1 Rocker arm
2 Rod head
3 Spherical roller bearing
4 Cylindrical roller bearing
5 Plain spherical roller bearing
Rocker arm in working positionRoller
Rocker arm with stop buffer Cylinder of the spring system
Loesche GmbH
Hansaallee 243
40549 Düsseldorf, Germany
Tel. +49 - 211 - 53 53 - 0
Fax +49 - 211 - 53 53 - 500
E-Mail: loesche@loesche.de
www.loesche.com
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