Water pump

A water pump comprising:

• a lower casing in which a rotor accommodating part having a rotor accommodating space formed downwardly concavely from an upper surface thereof is formed to protrude downwardly and a lower bearing mounting part is formed at a lower end of an inner portion of the rotor accommodating part;
• an upper casing which is coupled to an upper side of the lower casing and has an impeller accommodating space formed therein by the coupling with the lower casing and in which an inlet part in communication with the impeller accommodating space to introduce a fluid and an outlet part discharging the fluid are formed and an upper bearing mounting part is formed to extend from a lower end of the inlet part toward the impeller accommodating space;
• an impeller rotatably provided in the impeller accommodating space;
• and
• a rotor provided in the rotor accommodating space of the lower casing, coupled to the impeller, and having a rotation shaft of which both ends are rotatably coupled to the lower bearing mounting part and the upper bearing mounting part,
• wherein a support pin for supporting an upper end of the rotation shaft of the rotor in an axial direction is coupled to the upper bearing mounting part below an upper surface of the impeller, and
• wherein a lower surface of the support pin is formed as a flat surface, and the upper end of the rotation shaft is formed as a curved surface, extending convexly in an upper direction.