PURPOSE: To improve the reliability against mechanical impact by securing an outer rotor motor directly to an axle and jointing a segment type rotor magnet via pins.

CONSTITUTION: A motor yoke 9 and a rotor magnet 6 are secured via pins 7. The rotor magnet 6 is a 2-17 series rare earth magnet and bonded through epoxy resin. The yoke 9 and the rotor magnet 6 are jointed by applying adhesive onto the joint face 12 then they are secured by caulking the pins 7 partially. The rotor, formed in such a manner, is then fixed through a supporting frame 8 to a wheel 10. Then pulse current is fed to an armature 5 through a winding coil so that the rotor is rotated and an electric automobile is run. By such arrangement, the rotor can withstand large torque impact force during rotation.