NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Toshihiro Uchiyama) has developed high performance tapered roller hub unit bearings (HUB*1) for pickup trucks, large SUVs, and commercial vehicles. The newly developed tapered roller HUBs feature a unitized design and apply NSK low friction technology to improve operational reliability and fuel economy. NSK is targeting 5 billion yen in sales of these bearings in 2023.
*1 A HUB is a part that integrates a bearing with the hub on which automobile wheels are mounted.
Tapered roller HUBs have higher rigidity and longer service life compared to ball bearings of the same size, and are often selected for use in pickup trucks, large SUVs, and commercial vehicles. Ball bearing third-generation HUBs (HUB 3), which integrate the hub shaft and inner ring for improved ease of assembly, are already on the market. The difficulty in manufacturing tapered roller HUBs has, until now, prevented widespread adoption of tapered rollers in HUB 2.5 (“Generation 2.5,” with preassembled hub shaft and bearing) and HUB 3 lineups.
Lacking the convenience of a unitized design, it has been necessary for carmakers and mechanics to assemble and press-fit the hub shaft and bearing. Improper assembly or excessive press-fit force can lead to unwarranted noise and other modes of failure or reduced performance. In light of this, there is increasing demand for HUB 2.5 and HUB 3 to prevent the occurrence of assembly and press-fit related issues.
Around the world, the trend toward stricter environmental regulations and fuel economy standards is now driving aggressive improvements in fuel economy in vehicles of all sizes, not just in passenger vehicles, but also in larger SUVs and commercial vehicles. To keep pace with the trends, reducing friction in tapered roller HUBs is a vital undertaking.
- 1. Improved operational reliability by unitizing
- NSK has completed development of new models of HUB 2.5 with a preassembled tapered roller bearing and hub shaft. NSK is also developing new HUB 3 that integrate together (unitize) the hub shaft and inner ring. These preassembled, unitized, and preload controlled HUBs will prevent improper assembly and other modes of failure or reduced performance due to incorrect press-fitting of the hub shaft, thereby contributing to improved operational reliability (including in aftermarket repair and replacement scenarios).
- 2. Low friction technology
- By applying NSK’s expertise in low friction grease, seals, and high performance sealing caps, the new HUB 2.5 features approximately 20-35% reduced friction (compared to HUB 2). The new HUB 3 will be capable of reducing friction by an additional 10% (for up to 45% reduction compared to conventional HUB 2 products).
The newly developed tapered roller HUBs feature a unitized design and apply NSK low friction technology, thereby contributing to improved operational reliability and fuel economy.