(LFT series) Development of low friction torque ball bearing for high axial load
JTEKT Corporation (hereinafter JTEKT) has developed the “low friction torque ball bearing for high axial load” for automobile transmissions. JTEKT’s LFT technology was adopted to this developed product, which further reduced the friction torque and improved the axial load resistance. Thus, the weight and size of the product are reduced, contributing to the improvement of vehicle fuel efficiency.
Photo of developed bearing
1.Background of development
Ball bearings and tapered roller bearings are used in the automobile transmissions. Although tapered roller bearings are generally used at the position on which large load is applied, they have more friction torque than ball bearings.
To reduce the torque loss of transmission units, there is a demand for changing the bearings for transmissions to ball bearings.
However, we had a problem that deep groove ball bearings designed for intended use in the transmission unit become larger, heavier and more difficult to be installed since the axial load resistance of the conventional deep groove ball bearing is lower than that of tapered roller bearings.
2.Features of this developed product
Through the actions written below, a maximum of 50% torque loss is reduced in comparison to the tapered roller bearing (JTEKT’s LFT-Ⅱ) which has the equivalent allowable load level to the developed product.
(1) Improvement of axial load resistance
The raceway depth on the side which bears axial load is extended compared with the conventional deep groove ball bearings in order to reduce outer diameter by 10% compared with the conventional deep groove ball bearing and improve the axial load resistance (by 1.8 times compared with the conventional product).
(2) Development of LFT technology-adopted oil flow control cage
A decrease in bearing life due to foreign matters in lubricant and the friction torque loss due to oil agitation are reduced by modifying the cage shape in order to control the oil flow rate inside the bearing.
(Reduced a maximum of 80% oil flow rate and 15% agitation torque compared with the conventional product)
JTEKT has been putting a special focus on “friction” and “lubrication” since our predecessor “Koyo Seiko” time and pursuing low friction torque of bearings. In 1980s, we achieved the reduction of sliding friction on the inner ring rib face and roller large end face of tapered roller bearings and developed the world’s first low friction torque tapered roller bearing “LFT” that contributes to the improvement of vehicle fuel efficiency.
After the development, JTEKT continued further research on low friction torque and kept the evolution of tapered roller bearings to “LFT-II”, “LFT-III”, and “LFT-IV”. We have been always leading this field with our No.1 performance and responding to the recent growing environmental awareness.
JTEKT decided to establish the “LFT series” lineup, not only expanding the low friction torque technologies fostered through the development of tapered roller bearing, but also adopting the technologies to the ball bearings, hub units and other bearing-related products.
We will provide low friction torque bearings which contribute to the energy loss reduction for customers in the automotive industry as well as in various industries.
*LFT is the abbreviation for Low Friction Torque, and is a registered trademark of JTEKT Corporation.
3.Sales plan
| [Start of volume production] | Year 2020 |
| [Sales target] | 900 million yen/year |
| [Sales destination] | Automotive manufacturers, transmission manufacturers, etc. |
4.Production plant
Ball bearing production plant (Kameyama Plant, Tokushima Plant, etc.)
JTEKT Corporation has newly created a tagline “Key of your operation Koyo” for the bearing brand “Koyo”. JTEKT will continue contributing to every industry including automotive manufacturers as an indispensable partner to solve customers' problems through working with customers and to provide benefits.