As the automotive industry is rapidly evolving with the development and production of electric vehicles (EVs), hybrids, and other new energy vehicles, the maximum range on one single charge remains a concern for consumers. There is significant demand for larger capacity battery packs and improved efficiency that will allow for greater flexibility and peace of mind when purchasing EVs and other new energy vehicles.
Because of these market drivers, automakers are pursuing smaller and lighter automotive components, and developing faster, higher output motors operating at higher efficiencies. Accordingly, bearings used in powertrains, especially in electric motors, are being subjected to higher speeds and performance demands. Also, the downsizing of the motor brings demand for higher motor speed, and it is expected to run continuously for hours and in different conditions. This requires better bearing performances.
Bearings enable the motors to operate at higher speeds/rpm to meet the end-customer expectations. Also reduced friction losses are expected from bearings, enabling an improved distance coverage by reducing power consumption per unit of distance.
Bearing rotation at high speeds can cause failures like seizure or even bearing cage deformations by high centrifugal forces, and even the lack of proper lubrication could be one of the reasons for bearing failures. In order to reduce the frictional losses and improve the performance by enabling rigidity and better lubrication properties, engineering plastics are becoming the material solutions of choice for bearing cage applications.
The cage is an important part of the bearing function as it:
The cages are expected to have the following characteristics:
However, a source of friction inside the bearing can be the cage—it rotates eccentrically around the bearings axis and is in contact with the outer ring at one position. Metal cages cause more friction compared to polymer cages and demand a high level of consistent lubrication and high surface finish, which is an expensive secondary operation in production.
A material solution that delivers greater durability, extreme wear and abrasion resistance (as a result of its unmatched high fatigue), ductility and creep resistance (thanks to its 70-80% crystallinity levels) is DSM’s Stanyl® PA46 high performance polyamide. Other benefits of Stanyl PA46 include greater design freedom, as a result of the material’s 150% higher stiffness, strength and creep resistance at temperatures of 150-220°C when compared to other PAs and PPAs. Plus, it offers lower system costs, lower weight and less noise compared to metal.
Stanyl PA46 offers designers the flexibility to design the cage and produce it efficiently by eliminating secondary operations, unlike metals, for fine machining with smoother surface finishes. Using Stanyl as a cage bearing materials solution is also beneficial in terms of cost and performance. Various combinations with Stanyl, like glass fiber or Carbon fiber reinforcement, along with PTFE, can be selected as a suitable combination as per application demands.
Ready to learn more about eliminating friction in cage bearings? Contact us to learn more about our Stanyl PA46, or visit plasticsfinder.com for additional information, including technical data sheets.
Business Development Manager
02 October 2020
Business Development Manager
Amit Tolani is currently a business development manager at Envalior. He has 15 years of experience working closely with automotive OEM’s for introducing new technologies across the whole automotive value chain for powertrains and body design.