Development of Ultra-low-friction and Zero-leakage Mechanical Seal for High-Speed e-Mobility Shaft Sealing Applications 2020-01-1090
By the year 2020, EU legislation limits CO2 emissions for new passenger cars to a maximum of 95 g/km, and further reductions to 68 g/km are expected. Electric motors with high power density often need shaft cooling in combination with increased rotational speeds to boost efficiency. Especially, the low friction and the durability of the sealing faces is essential to overcome the severe friction condition of the high-speed rotation.
This challenge can be solved by using the revolutionary GlideXTM sealing technologies. These seals feature advanced texturing, a new surface technology that enables microscopic flow control in the dynamic sealing faces. Advanced texturing reduces leakage to the level of insignificance and up to 90% less friction, compared to a non-textured mechanical seal.
The advanced texturing allows for a thin liquid-sealing film between the sealing faces. The liquid lubrication becomes dominant at low speeds; at high speeds, the gas lubrication becomes dominant by preventing the liquid from flowing into the sliding surfaces. As a result, the seal can keep low friction in both low- and high-speed rotations due to the lower viscosity of air over fluids. This leads to less wear, a longer service life, and less power/fuel consumption. Less power consumption relates to higher battery range; lower friction leads to a reduction in CO2 emissions compared to hybrid and ICE vehicles. The proposed sealing technologies can be used for applications like ORC compressors, water pumps, e-motor shaft cooling, reduction gear sealing, fuel cell compressors, and more.
Herein, the developments of ultra-low friction and zero-leakage mechanical seal for high-speed e-motor shaft are explained. Both numerical calculations and experiments are performed to confirm the fluid film thickness, friction coefficient, and amount of leakage. Furthermore, application examples for e-motor shaft cooling system, reduction gearbox, and water pumps are introduced.