The Dual Challenge:
In the past, our client sourced electrical auxiliary water pumps from various manufacturers. Despite their good design, the drive performance was consistently too weak across all brands. The client’s requirement was clearly outlined to us: How can we achieve quadruple the performance of the pumps while utilizing the existing design? But that was not all: The rotor was also to be used simultaneously as an impeller for a pump, including bearing on a shaft.
One thing was clear: Achieving a fourfold performance in the pump demands a much stronger magnetic material than the previously used hard ferrite. Sintered NdFeB was therefore the only viable option. Moreover, the rotor operates in water. The NdFeB-coated magnets need protection against contact with the cooling medium.
The rotor’s magnetization is defined as 8-pole: One magnetic pole is created using two individual NdFeB magnets. Hence, 16 block magnets are installed per rotor. To prevent these individual NdFeB magnets from touching each other, pockets for positioning the block magnets are integrated into the rotor. After the assembly of the individual magnets, a second injection molding process is conducted to seal the rotor and protect it from contact with water.
We have successfully navigated through a series of complex tasks to arrive at a competent solution:
- Practical application as a drive has been achieved with a blade water pump rotor - showcasing our ability to adapt and innovate
- The magnet is directly installed into the pump – complete with an integrated bearing on the shaft - demonstrating our attention to detail
- Despite the challenges of water exposure, we managed to utilize high-performance NdFeB material, facilitated by a special magnetization technique. This results in enhanced performance through the innovative construction of a pole with two permanent magnets, leading to an 8-pole magnetization of the rotor.