A Self-Adaptively Loading Mechanism for Planetary Cylindrical Roller Traction Drives

Abstract

A planetary cylindrical roller traction drive was developed. It is comprised of a sun roller, three planet rollers, an outer ring, a planet carrier and an input shaft. The sun roller is hollow, and is connected through three segments of logarithmic spiral profile to the input shaft. As the input shaft rotates relative to the sun roller, a wedging action takes place between the input shaft and the sun roller; this makes the sun roller produce a certain amount of radial displacement, so an appreciable amount of normal load is thus generated between the rollers of the planetary traction-drive device. The greater the input torque is, the stronger the strength of the wedging action, and the greater the contact load, and vice versa; so this device is self-actuating. Here, as cylindrical rollers are used in the planetary traction-drive device, the spin motion as would present in the case that tapered rollers are used will not occur. This design offers an alternative way to solve the problem of self-adaptively loading of planetary cylindrical roller traction-drive devices.