Since March 1, 2010 our headquarter is located in Essen.
From 26.-30. October 2010 ThyssenKrupp Magnettechnik is represented at the world's largest sheet metal working exhibition.
Please visit our stand E22 in exhibition hall 16!
Design and types
The disc and concentric ring couplings developed by us are manufactured and offered – according to application, capacity and required performance – in the following materials:
:: Ceramic materials, hard ferrite (HF): HF 8/22, HF 24/20
:: Metallic materials, AlNiCo: AlNiCo 18/10, AlNiCo 36/14, AlNiCo 40/5
:: Rare Earth materials: SmCo, NdFeB
In practice these elements have proved themselves in numerous applications. With relatively small magnet sizes they allow the transmission of great torques in closed spaces through partitions without the use of gaskets, seals and glands. Of particular advantage is the fact, that through correct structural design utilising air gaps, all couplings work free of friction and thus free of wear.
When choosing a coupling type please note that at the start of torque movement, and in some cases through shock loading, higher torque can occur than could for instance be calculated from nominal power and number of revs. of a motor. If the coupling is not just to run purely as an overload coupling, then possible additional starting torque must also be considered. The drive gear should be run up slowly or the size of coupling chosen so high that the coupling moment is always above the maximum driving moment. If the coupling should break away no magnetic changes will occur. However, for synchronisation it is necessary to bring both coupling parts to a standstill and run up again.
Instructions for application and assembly of disc couplings
The
application possibilities are similar to those subsequently described
for concentric ring couplings; the partition walls can be plain and flat.
It should be noted, that the relatively high axial power must be absorbed
by a suitable bearing. Are single ring magnets delivered by us for self-construction
by the customer the following has to be noticed: The distance between
the rings in our packaging is not allowed to be reduced in order to maintain
the magnetic values. Furthermore the magnets should not be twisted against
each other before they are fitted into the housing. In the case of delivering
single rings the magnetisation of the completed coupling is recommended.
After the fitting into the iron mounting a decrease of the torque value
can only be expected at a small rate of 5 to 10%. Even if the magnets
have direct contact or are twisted against each other.
Our instructions are general suggestions relating to the materials. They do not discharge the user from noticing other constructive aspects which might occur specially in each individual case when couplings are made ready for use. We are gladly prepared to provide assistance with the construction.
Instructions for application and assembly of concentric ring couplings
Transmission
of turning movement from wet to dry media in liquid and gas meters. Because
of high rigidity small angle movements from closed spaces can be transmitted
to indicating instruments.
Application: maintenance-free pumps, vacuums, compressor construction
and many more.
Most designs need an interface between inner and outer compartments made from a tubular or cupshaped, non-magnetic material. See fig.2. In order to avoid eddy currents this should be electrically non-conductive e.g. made of plastic. For high pressures one could use austenitic chrome-nickel steels with high electrical resistance e.g. REMANIT 1.4301. Where the number of revolutions (rpm) is higher, care must be taken to allow sufficient cooling of the metallic partition wall. To level out the resulting power loss, a correspondingly higher required power should be chosen.
If concentric ring couplings in HF 8/22 are used without soft iron mountings the given torque and rigidity are reduced by approx. 10%. HF-materials are extensively resistant to chemicals. In special cases metal protection by using non-magnetic chrome-nickel steels and plastic is possible. Linear torque increase is possible through a stringing together of individual rings or systems, but then the whole unit must be completely magnetised.
Temperature behaviour of the magnets
The working range of HF-couplings is between –30°C and +150°C.
If the working temperature is raised or lowered, the transmitted torque
decreases or increases linearly by approx. 4*10-3K-1 = 4%/10°C. For
SmCo –190°C to +250°C; in this range torques increase or
decrease by 0.8%/10°C. The respective coupling reaches its initial
value again at room temperature as the temperature effect is reversible.
For temperatures above 250°C we develop special couplings in AlNiCo
on request. This type of AlNiCo coupling can be used at temperatures up
to 400°C maintained over long periods.
