Abstract: In a totally-enclosed fan-cooled motor wherein a drive side of a rotation shaft and a side opposite to the drive side are held by means of bearings and so that drive power would be transmitted from the drive side of the rotation shaft with which a rotor is formed into one body, wind is sent to an outer side of the motor in an axial direction of the rotation shaft by means of an external fan provided on the side opposite to the drive side to cool a stator in the air-tightly closed motor and air in the motor is circulated by means of an internal fan provided in the motor to cool a rotor, provided is a radiator mounted to the rotation shaft so as to be located on an outer side of the bearing holding the drive side of the rotation shaft, outside the motor, and in the vicinity of the bearing. This allows a cooling effect of the bearing provided on the drive side to be improved.

Abstract: An electric motor includes a rotor shaft arranged in a casing and having an axial hollow bore formed therethrough for passage of lubricating oil, a rotor, a stator, a pair of bearings each having an inner race and an outer race, a pair of bearing fixing parts supporting the rotation of the rotor shaft, and bearing cooling devices each having a cylindrical heat dissipation portion fixedly secured to the rotor shaft so as to be in contact with either one of end faces of the individual inner races, the heat dissipation portion extending from the one end face of each inner race to a side opposite to the bearings. A pair of spaces between rotor-side end faces of the bearings and the bearing fixing parts, respectively, are in communication with ring gaps between the heat dissipation portions and the rotor shaft, respectively, through radial communication holes in the rotor shaft.

Abstract: In a totally-enclosed fan-cooled motor wherein a drive side of a rotation shaft and a side opposite to the drive side are held by means of bearings and so that drive power would be transmitted from the drive side of the rotation shaft with which a rotor is formed into one body, wind is sent to an outer side of the motor in an axial direction of the rotation shaft by means of an external fan provided on the side opposite to the drive side to cool a stator in the air-tightly closed motor and air in the motor is circulated by means of an internal fan provided in the motor to cool a rotor, provided is a radiator mounted to the rotation shaft so as to be located on an outer side of the bearing holding the drive side of the rotation shaft, outside the motor, and in the vicinity of the bearing. This allows a cooling effect of the bearing provided on the drive side to be improved.

Abstract: An electric motor includes a rotor shaft arranged in a casing and having an axial hollow bore formed therethrough for passage of lubricating oil, a rotor, a stator, a pair of bearings each having an inner race and an outer race, a pair of bearing fixing parts supporting the rotation of the rotor shaft, and bearing cooling devices each having a cylindrical heat dissipation portion fixedly secured to the rotor shaft so as to be in contact with either one of end faces of the individual inner races, the heat dissipation portion extending from the one end face of each inner race to a side opposite to the bearings. A pair of spaces between rotor-side end faces of the bearings and the bearing fixing parts, respectively, are in communication with ring gaps between the heat dissipation portions and the rotor shaft, respectively, through radial communication holes in the rotor shaft.