First bearings with bioplastic cages, NSK supports sustainable productionERT

NSK has announced its first rolling bearings with cages made of a bioplastic material derived from renewable biomass sources – mainly plants. The company says that the cages will cut lifecycle CO2 emissions by 91% compared to conventional plastics made from fossil fuels.

Unlike other bioplastic materials that have problems in high temperatures, tests have shown that the new cage material can withstand temperatures of up 120°C. The heat-resistant cages will be offered initially on NSK’s 60 and 62 series of deep-groove ball bearings, which are typically used for applications such as for air-conditioning fan motors. As well having to be reliable, bearings for these motors need to exhibit low noise and friction. Tests have shown that bearings with the bioplastic cages have similar noise and friction levels to conventional cages made from polyamide 66.

Using computer-aided engineering in the development process allowed NSK to evaluate dimensions, shape and deformation, and verify the suitability of existing mould tools to handle the new bioplastics. It also assessed attributes such as strength and quality, and used digital twin simulations to evaluate stresses in the cages under operating conditions. The company validated the cage performance by real-world testing of physical prototypes. By combining the two approaches, it says it cut the cage development time to one-third of that needed using conventional processes.

NSK reports that the new bioplastic cages demonstrate similar strength, heat resistance, grease resistance and weld strength to polyamide 66, as well as comparable stiffness, fatigue resistance, creep resistance and impact resistance. The company plans to expand its use of bioplastics to products for other sectors, such as the automotive industry, and for OEMs looking to develop environmentally friendly products.