FST advances in-wheel motor seals for EVs, commercial vehicles

Weinheim, Germany – Freudenberg Sealing Technologies (FST) is offering a patented sealing geometry for in-wheel motors (IWM) used in applications ranging from electric cars to commercial vehicles.

In electric vehicles, it said, IWMs enable components such as transmissions, brakes, and suspensions to be located much closer to the power-transmission point or even to be completely eliminated, noted the company, highlighting the benefits of the motor technology.

Vehicles equipped with the technology, therefore, have enhanced “wheel-specific torque control and comfort as well as more design-space, resulting in “a better driving experience, greater range and more flexibility for developers.”

FST said IWMs also offer advantages for buses due to their lower centre of gravity, tighter turning radius and higher load capacity, and can be used as a combined trailer-drive for e-trucks or as a generator for refrigerated trailers with independent power supply.

“The technical challenges for the seal are mainly to ensure reliable protection against dirt and water while minimizing friction losses,” said product developer Luca Breusa, noting that “at any speed [FST’s seal design] provides optimal protection against dirt and water.”

According to the release, a key feature of the Freudenberg seal is its dynamic adjustment of sealing effectiveness and friction according to the rotational speed of the wheel – thereby preventing major friction losses. 

Due to the sealing-lip positioning, high contact pressure maximises sealing performance at low rotational speeds, while at higher speeds both the contact pressure and the friction are significantly reduced by the generated centrifugal forces, explained Breusa.

One of two main design options, FST’s cassette seal features a double sealing lip and mating contact surface installed in a closed system, featuring “precisely matched materials made of stainless steel and special rubber compounds.”

The cassette seal can achieve up to 500,000km and protection class IP67, making it “a maintenance-free, self-lubricating solution throughout its entire service life,” the German sealing specialist added in its 24 Oct press release.

The second design is a V-seal, employing wear-resistant elastomers with “excellent sliding properties, combined with attractive manufacturing costs, create a plug-and-play solution designed for flexible applications.”