Bearings for the environment

Last year, NSK introduced the world's first bioplastic cage for rolling bearings. Now the company is presenting the first product range with cages made from renewable resources. They will be available for Series 60 and 62 deep groove ball bearings, which are used in air conditioning fan motors and other applications. In the future, NSK will continue to expand this product portfolio and its associated application possibilities, offering OEMs developing environmentally friendly products an alternative to conventional cage materials.

Manufacturing bearing cages from a plastic derived from renewable biomass sources (mainly plants) enables a significant reduction in product-specific CO2 emissions over the entire life cycle. Compared to conventional plastic cages made from fossil fuels, the CO2 reduction is 91%. This means that the manufacturer and also the user are making a contribution to climate protection.

Until now, components made of bioplastics were not suitable for such applications because their heat resistance was too low. However, the cage material selected by NSK can withstand operating temperatures of up to 120 °C, as confirmed by endurance tests.

The application of the cages in air-conditioning fan motors was chosen by NSK partly because this market is also set to grow in Europe and manufacturers are keen to improve their sustainability footprint by supplying components with the smallest possible carbon footprint.

Rolling bearings are a key component in air conditioning fan motors. Many manufacturers use NSK's 60 and 62 series deep groove ball bearings here, and now they can use the world's first 100% bioplastic cages available to the mass market and improve the carbon footprint of their products.

The use of modern CAE technology in the development process enabled NSK designers to optimize the dimensions of the cages in advance, calculate their deformation in operation and check the suitability of existing molds. It was also possible to evaluate key properties such as strength and service life in the computer-aided simulation. The "digital twin" of the bioplastic cages was used in particular to determine the loading properties of the cage under operating conditions.

Based on these simulation results, NSK developers were able to further improve the properties of the cages in the prototype phase within a short period of time. Through parallel and iterative optimization of the digital twin (through simulation) and the real prototypes (in real-world test series), NSK was able to reduce the development time of the cages to a third of the time compared to the traditional approach.

Rolling bearings for air-conditioning fan drives are expected to be highly reliable, with low noise and minimal friction. Tests conducted by NSK confirm that the bearings made of bioplastic cage have equivalent noise and friction performance to conventional cages made of polyamide 66.

In addition, the new cage exhibits similar strength, heat resistance, grease resistance and weld strength to polyamide 66. Also comparable are stiffness, fatigue resistance, creep resistance and impact strength. 

NSK will continue to expand the use of bioplastics in products for other applications, such as the automotive industry. In this way, the company is pursuing its goal of further reducing carbon emissions and contributing to the creation of a CO2-neutral society.