Patent ID: 9074345
Filing Date: 2015-07-07
Classification: B60L,E02F,F16H

Abstract:
1. A swing device for a construction machine comprising: a reduction gear which is mounted in a vertically extending manner on an upper revolving structure mounted on a lower traveling structure by means of a revolving ring; an electric motor mounted on an upper side of said reduction gear and having an electric motor shaft which rotates upon supply of electric power thereto; a hydraulic motor mounted on an upper side of said electric motor, a lower end side of a hydraulic motor shaft which rotates upon supply of operating oil thereto being coupled to an upper end side of said electric motor shaft; and an output shaft for outputting to said revolving ring the rotation of said electric motor shaft and said hydraulic motor shaft subjected to speed reduction by said reduction gear, wherein said electric motor has an electric motor casing lower end side of which is mounted to said reduction gear and an upper end side of which is formed by a lid portion for blocking drain oil from said hydraulic motor, a shaft insertion hole through which the upper end side of said electric motor shaft is inserted is provided in said lid portion of said electric motor casing, a bearing for rotatably supporting the upper end side of said electric motor shaft is provided between said shaft insertion hole and said electric motor shaft, the lower end side of said hydraulic motor shaft extends downwardly toward and into said shaft insertion hole, and is arranged to be coupled to the upper end side of said electric motor shaft, and a seal member for allowing the supply of the drain oil from said hydraulic motor to coupling portions of said electric motor shaft and said hydraulic motor shaft and for preventing the drain oil from entering an interior of said electric motor casing is arranged to be provided between said shaft insertion hole and said electric motor shaft and being located upwardly of said bearing.