EKK featured in MTZ Magazine
The leading German specialist magazine for engine development MTZ has published an extensive background article in its November issue on Eagle Industry’s GlideX™, the low friction sealing solution for e-drives.
MTZ is an 80-page magazine that is published 11 times a year, containing high-quality content that is created in close collaboration with leading universities, OEMs, suppliers, and service providers in the industry. The magazine is read by over 50,000 managers across 50 countries.
The article, written by EKK’s Hiroki Inoue, Senior Engineer from the Seal Engineering Department at Saitama (Japan), describes how EKK’s GlideX mechanical seals establish near-to-zero leakage performance at extreme low friction levels over a large speed range. With this new product family for electric motor rotor cooling and reduction gears, a significant roadblock towards highly efficient and high-speed electric drive trains is cleared.
The need for electric drive trains
Motivated by the electric vehicle range expectations of consumers, efficiency requirements and the need to bring affordable, exciting, and environmentally friendly electric mobility to the roads of today and tomorrow, electric drive trains are speeding up. As maximum rotational speed is increasing, electric motor designers are facing challenges: friction and cooling at rotating elements play an increasing role at high speed rotation. Additionally, the performance related to friction losses needs to be stable over a wider speed range.
That’s why EKK developed this new generation seals, which can seal the liquid-cooled rotors and adjacent reduction gears excellently without compromises in friction losses. In addition, they exceed the traditional speed boundaries. With the application of advanced surface textures, EKK managed to create additional controls, which overcome the traditional compromise between friction and leakage in dynamic seals. The article describes in detail the design and function of the new GlideX seal for electric motor cooling and gearboxes.
A new generation of mechanical seals
The dynamic sealing positions in electric motors tend to be technically challenged as the sliding speeds often exceed technical limitations of conventional sealing configurations. To overcome these limitations, the physical compromise between leakage and friction needs to be challenged. This challenge is accepted and solved by the development of a new generation of mechanical seals at EKK that use advanced surface textures on the sealing surface.
With the introduction of these advanced surface textures in the sealing faces, EKK has gained further control of the micro-flows between the dynamic sealing faces. This is the core of controlling dynamic friction and leakage. A combination of simulation and different testing methods like friction measurement, dynamic gap visualization and dynamic condition testing were used to gain the necessary knowledge. For the numerical analysis, advanced models based on Reynolds equations, combined with EKK testing experiences are used to achieve high prediction accuracy.
Various dynamic tests
To show the friction levels and transition from fluid to air friction in the sealing faces a test setup was chosen which combines simulation, visualization, and torque measurement. The leakage performance and wear resistance were tested in several dynamic tests. In these tests the conditions applied were typical for fluid cooling and gearbox application.
The test results show that understanding the design of the textures and being able to accurately simulate the result in friction and film thickness enabled EKK to create customer and condition specific solutions. These solutions can improve the motor friction losses to a level of vehicle range relevancy. By the application of the textured sealing technology, electric motors can be constructed at considerably higher maximum rotation speeds, which can lead to a longer drive range, more efficiency, and lower battery cost. EKK will further expand the modular portfolio for electric motor applications and make excellent sealing available for everyone who needs a dry motor without compromises regarding friction losses.
Read the article in MTZ: