Patent ID: 8083631

Claim:
A planetary gear type gearbox comprising: a front-stage transmission section including an input shaft to which power is inputted; and a rear-stage transmission section including an intermediate shaft coupled to the front-stage transmission section and an output shaft for outputting power, the front-stage transmission section including a first planetary gear train having a first sun gear, a plurality of first planet gears meshing with the first sun gear, a first carrier connected to the input shaft with the first carrier rotatably supporting the first planet gears, and a first ring gear connected to the intermediate shaft with the first ring gear meshing with the first planet gears, a second planetary gear train having a second sun gear integrally and rotatably coupled to the first sun gear, a plurality of inner peripheral side second planet gears meshing with the second sun gear, a plurality of outer peripheral side second planet gears meshing with the inner peripheral side second planet gears, a second carrier connected to the input shaft with the second carrier rotatably supporting the inner peripheral side second planet gears and the outer peripheral side second planet gears, and a second ring gear meshing with the outer peripheral side second planet gears, a first clutch configured to selectively couple/uncouple the input shaft and the intermediate shaft, a second clutch configured to selectively allow/prevent rotation of the second sun gear, and a third clutch configured to selectively allow/prevent rotation of the second ring gear.