01Magnet rotors

 

In the past magnetic rotors have been produced in several complex consecutive production processes. Magnetic rings have been produced and in a second production step glued with the shaft. Additionally, according to the customer‘s requirement, a bursting protection, by a stainless steel bushing has been shrunk or glued on the magnets.

Thanks to our new production technique, it is now possible to unify all production steps in only one work step.

Potential applications

For rotors that operate at high speed, e.g. vacuum cleaner motors required to comply with the new energy efficiency class A***.

Magnetic properties

  • Material NdFeB 72/70 pw
  • Isotropic
  • Remanence typ. 700 mT
  • Magnetization possible on cicumference
  • Binder approx. 2 % Epoxy

Important properties

Other important properties see into the following table.

 

Components:

  • Stainless steel sleeve with a wall thickness of 0.2 mm
  • Ring magnet made from NdFeB magnetic material
  • Spindle or iron core
     

Production process:

  • Pressing the ring magnet and joining it in the sleeve in a single step
  • Joining the spindle with the iron core in the magnet ring, which is not yet cured
  • Curing of the epoxy
  • Magnetisation of the complete assembly


Advantages of the new process:

  • no adhesive bonds
  • no adhesive gap and therefore less imbalance
  • no additional cost for gluing
  • more efficient production because the complete assembly "magnet joined in a sleeve with spindle" can be produced in one step
  • low use of magnetic material since wall thicknesses of up to 1.5 mm can be implemented
  • high degree of automation possible
  • motor speeds of more than 50,000 rpm are possible
  • the magnets can be enclosed well in the stainless steel sleeve
  • joining magnets into pans is also an option 

Advantages of the magnetic material:

  • Magnetic alloy without dysprosium
  • simple manufacturing process and high precision of the magnets since they are not sintered
  • multi-pole rings are possible because the material is isotropic