Vibration motor

A vibration motor, comprising:

• a rotor shaft;
• a first magnet and a second magnet arranged on the rotor shaft to face each other;
• a circuit board, wherein the circuit board comprises a hollow hole, wherein the rotor shaft passes through the hollow hole, and coils arranged thereon, wherein the coils respectively face the first and second magnets;
• a housing, wherein the housing forms an inner space, the rotor shaft and the circuit board are mounted in the inner space, to fix the circuit board;
• a shaft passing through the rotor shaft and fixedly erected in the housing;
• a first yoke and a second yoke, wherein the first and second magnets are respectively installed on the first yoke and the second yoke, and the first yoke and the second yoke are fixedly coupled to the rotor shaft to integrally rotate along with the rotor shaft;
• a weight installed on the first yoke or the second yoke;
• and
• a bearing portion, wherein the bearing portion comprises a plurality of bearings coaxially arranged with the shaft, at least one of the plurality of bearings is arranged to surround the shaft,
• the rotor shaft is fitted with the plurality of bearings to rotate relative to the shaft, the rotor shaft comprises a cylindrical shape in close contact with outer rings of the plurality of bearings, and the rotor shaft comprises a diaphragm portion, wherein the diaphragm portion extends toward the shaft and is interposed between the plurality of bearings.