JTEKT Developed Long-life Needle Roller Bearing For Planetary Shafts(Pic)

JTEKT Corporation (head office in Chuo-ku, Osaka; president Kohshi Yoshida) has succeeded in developing and bringing to market a needle roller bearing for planetary shafts having eight times the life of conventionally used needle roller bearings. Currently there is a trend regarding planetary shaft bearings to move from full complement roller bearings to needle roller bearings with retainer because of the latter type low torque, ease of installation, and superior high-speed performance. However, this switch to needle roller bearings has led to decreased bearing load capacity because of the reduced number of rollers and increased contact surface pressure between the rollers and shaft because of the more compact drive unit, resulting in limited bearing life. To resolve this problem, JTEKT has developed a needle roller bearing that retains the conventional features of low torque and superior high-speed performance while also possessing high load capacity and long life. By utilizing an original type of heat treatment that extends life by optimizing bearing surface hardness and microstructure as well as by applying shot peening, a type of surface treatment that elevates metal fatigue strength, to the planetary shaft functioning as the bearing inner ring, JTEKT has secured life eight times that of conventionally used needle roller bearings and resolved the problem of load capacity. JTEKT is working aggressively to market this long-life needle roller bearing for planetary shafts, particularly for application on automobile CVT transmissions, whose popularity is growing rapidly. Shot peening is a technique whereby a great number of hard, round pellets are shot at a material surface in order to elevate metal strength by creating a large amount of residual compressed stress on the material surface.