Automotive - 2011-07-15
NSK has developed a silent needle roller bearing that cuts noise to a third that of the conventional product. This innovation is perfect for electrical components mounted in vehicles with extremely quiet interiors while driving under the power of an electric motor, such as electric vehicles (EV) and hybrid vehicles (HEV).
As a first application example, NSK new Silent Needle Roller Bearing is already fitted to the air-conditioning compressor of some EV models but can be applied to a number of further components in the same way. NSK will promote this product for meeting the growing need for quieter bearings with the electrification of vehicles. It expects annual sales of 200 million yen (around 1.8 million euro) by 2015.
The ends of rollers (rolling element) in needle roller bearings used in automotive electric components are crowned (i.e. given a curved arc) to make the bearings able to withstand a heavy load. With the conventional crowning method, the roundness of the roller ends is inferior compared to the central part of the roller, resulting in loud noise from the bearing under conditions in which the roller has a large tilt.
For this reason, in EVs and HEVs, in which the vehicle interior is extremely quiet, the operating noise of electric components that traditionally would not have been noticeable can disrupt the passengers comfort.
Product features – improved roundness of crowning –
NSK improved the roundness of the roller crowning compared to the conventional product by developing a high-precision machining method.
The noise level (sound pressure) generated by the bearing was cut to no less than 1/3 that of the conventional product. The product will help make more silent, comfortable vehicle interiors in EVs, HEVs, and luxury cars in which a very quiet ride is required.
NSK has achieved compact, lightweight and low torque and low-noise applications for automobiles by leveraging its four core technologies (tribology, materials, analysis, and mechatronics). The company has been developing these technologies for over 90 years, and is continuing to create products that will improve fuel efficiency, comfort and safety in modern vehicles.
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