NSK reveals world’s first bearing line-up to feature a bioplastic cage

Following its development in 2021 of the world’s first bioplastic cage for rolling bearings, NSK can now reveal its initial product line-up. The new heat-resistant cage will be available on its 608, 6201 and 6202 series of deep groove ball bearings, which are ideal for fan motors in air conditioners. Moving forward, NSK will continue expanding its product portfolio and the associated range of applications for OEMs looking to develop environmentally friendly products.

By manufacturing the bearing cage from a bioplastic material - which derives from renewable biomass sources (mainly plants) - it is possible to reduce lifecycle CO2 emissions by 91% in comparison with conventional plastics made from fossil fuels, thus contributing to carbon-neutral initiatives. As a point of note, conventional bioplastic components have suffered from low heat resistance, but tests show that the cage material selected by NSK can withstand operating temperatures of up 120°C.

Sales of new air conditioners are set to increase as they enter the price range of a growing number of households across Europe, while homes and workplaces with existing air conditioners are looking to upgrade due to the Covid-19 pandemic and the benefits that enhanced ventilation bring. Bearings are a key component within the fan motors of air conditioners. By taking advantage of NSK 608, 6201 and 6202 series deep groove ball bearings and the world’s first 100% bioplastic cage brought to mass market, air conditioner OEMs can boost their sustainability credentials.

Using CAE technology in the development process allowed NSK to evaluate dimensions, shape and deformation, and verify the suitability of existing mould tools. The company could also assess important attributes such as strength and quality. In particular, NSK used digital twin simulation to evaluate cage stress characteristics under operating conditions.

Accelerated by simulation results, NSK conducted further validation of cage performance during rotation via the real-world testing of physical prototypes. By applying the two perspectives in parallel, the company reduced cage development time to one-third of that of conventional processes.

In addition to high reliability, bearings for air conditioner fan motors are required to exhibit low noise and friction. NSK’s functional evaluation tests confirmed that bearings featuring the bioplastic cage have an equivalent noise and friction performance to that of conventional cages made from polyamide 66.

Ultimately, alongside its potential to help OEMs develop carbon-neutral products, the new bioplastic cage demonstrates equivalent strength, heat resistance, grease resistance and weld strength to that of polyamide 66, as well as comparable stiffness, fatigue resistance, creep resistance and impact resistance.

Moving forward NSK will continue expanding its use of bioplastics in products for other sectors, such as automotive, with a view to further reducing carbon emissions and contributing to the creation of a carbon-neutral society. 

Picture 1): NSK manufactures its latest cage for rolling bearings from a bioplastic (plant-based) material. Photo: Kai Beercrafter/ Shutterstock