| 摘要 |
A reduction gear (12) is mounted on a revolving frame (3A), an electric motor (22) having an electric motor shaft (27) is disposed on an upper side of the reduction gear (12), and a hydraulic motor (34) having a hydraulic motor shaft (41) is disposed on an upper side of the electric motor (22). A shaft insertion hole (23E) through which an upper end side of the electric motor shaft (27) is inserted is provided in a lid portion (23B) of an electric motor casing (23). A male spline portion (41A) provided on a lower end portion of the hydraulic motor shaft (41) is spline-coupled to a female spline portion (27B) provided in an upper end portion of the electric motor shaft (27). A bearing (28) is provided between the shaft insertion hole (23E) and the electric motor shaft (27), and a pressure tight seal (43) is provided by being located upwardly of the bearing (28). Hence, spline coupling portions of the female spline portion (27B) and the male spline portion (41A) are constantly lubricated by making use of drain oil which leaked from the hydraulic motor (34). |
