Patent attributes
A planetary gear unit includes a first gear, a second gear, and a third gear arranged coaxially while allowed to rotate relatively. A first planetary gear and a second planetary gear are integral, and a third planetary gear and a fourth planetary gear are integral. The planetary gears are rotatably supported by a carrier. The first planetary gear is meshed with the first gear, the second planetary gear is meshed with the second gear, the third planetary gear is meshed with the second gear, and the fourth planetary gear is meshed with the third gear. A gear ratio between the first planetary gear and the first gear is different from a gear ratio between the second planetary gear and the second gear, and a gear ratio between the third planetary gear and the second gear is different from a gear ratio between the fourth planetary gear and the third gear.