Abstract
This study discussed about the initiation of the failure of driven shaft and also proposed an effective technique to reduce the moments applied onto the driving shaft of monorail for forest industry. At first, geometrical change of the tooth was observed after the rack rail was used for about 200 hours (employed for about 30days) at civil engineering construction site. The power unit of monorail was driven with traction on the original and worn rack rail in the short range at laboratory. The variation of torsional and bending moment applied onto the driven shaft were measured with respect to the rotational angle of the shaft when the driven gears were engaged with original and worn rack rail, respectively. To reduce the wear of the rack rail, pitch diameter of pins in which number of pins was also reduced was decreased in comparison with that of conventional gears. The results showed that a reduction of 73% in average torsional moment applied onto the driven shaft of the front gear was obtained. Shear sliding on the surface of the rack rail tooth was prevented while by applying the modified gear. In conclusion, to decrease pitch diameter of pins in which number of pins was also reduced to prevent the failure of driven shaft of monorail for forest industry was effective.
