2011

A new cage shape delivering high performance bearing capabilities and a 25% reduction in rotating torque!

NTN Corporation (hereafter, NTN) has developed a “low torque deep groove ball bearing (without seal)” that reduces rotating torque by 25%^*1, as part efforts to reduce CO₂ emissions and improve fuel efficiency. This comes amidst calls for greater efficiency of ball bearings without seal used in automobile and motorcycle transmission systems into the future.

To improve fuel efficiency in automobiles and motorcycles, NTN developed “high rigidity and ultra low torque tapered roller bearings”^*2 for use in transmission systems, which has been applied by a large number of customers. There has been growing demand for an ultra-low torque version of the deep groove ball bearing, which uses steel balls as the rolling element.

More recently, manufacturers of automobile-related parts have been implementing measures to reduce stirring resistance by reducing the volume of oil within the transmission system, as part of efforts to improve fuel efficiency and develop more environmentally friendly automobiles. To achieve this, there has been an increasing shift from dip-feed lubrication to fog lubrication methods. Maintaining a low level of torque has remained a key focus of development with the use of this fog lubrication.

NTN has concentrated efforts on the shear resistance^*3 of oil present between the cage and steel ball of deep groove ball bearings as the main factor affecting rotating torque. By employing a new shape cage pocket and controlling the lubricating oil within the bearing itself, a low-torque version of the bearing could be developed while retaining the same fundamental characteristics such as a long operating life and rigidity.

The low torque deep groove ball bearing developed by NTN features a 25% reduction in rotating torque compared to conventional products, and provides the same level of performance with a lower volume of lubricating oil through the use of fog lubrication, contributing to improvements to fuel efficiency and more environmentally friendly operation.

NTN exhibited this new bearing on show at the Automotive Engineering Exposition 2011, held at the Pacifico Yokohama Exhibition Hall from May 18 to 20, 2011, and will be releasing the bearing globally in the near future.

*1 Compared to standard deep groove ball bearings using fog lubrication

*2 February 20, 2006 Press Release: NTN Develops Ultra Low-torque Tapered Roller Bearings with Rotating Torque Reduced by 1/2

*3 The shear resistance of lubricating oil refers to the resistance force at the surface of the lubricating oil when moving an object over it

Features Compared to conventional products (standard deep groove ball bearings)

1. Rotating torque: 25% reduction (with fog lubrication conditions)
   → The use of a new cage pocket (with a concave shape) helps to reduce the shear resistance of the lubricating oil
2. Long-operating life, rigidity, rotational performance: same or higher
   → Achieves high bearing performance with a low volume of lubricating oil such as fog lubrication method

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