Patent ID: 9488177
Filing Date: 2016-11-08
CPC Classification: F04D

Claim Text:
1. A water pump comprising: a lower casing; an upper casing sealably mounted on an upper side of the lower casing, the upper casing including a water inlet and a water outlet; a fixed shaft fixed to a center of the lower casing by a shaft fixing unit, the lower casing and the fixed shaft being integrally formed with each other, the fixed shaft penetrating the center of the lower casing and protruding inside the lower casing and inside the upper casing; a stator disposed inside the lower casing; an outer rotor that is arranged at a predetermined gap to an outer circumferential surface of the stator and is rotatably supported on the fixed shaft; an impeller that is disposed inside the upper casing and that is rotatably supported on the fixed shaft; and a power transmission unit that is installed between the impeller and the rotor and transmits rotational force of the rotor to the impeller by a magnetic force, wherein the shaft fixing unit includes a concave ring groove formed around an outer circumferential surface of the fixed shaft, and scratches formed at a plurality of portions where the fixed shaft contacts the lower casing during the insert-molding of the fixed shaft, thereby reinforcing a bonding force, preventing a vertical movement of the fixed shaft and sealing the lower casing, wherein a first one of the portions is formed above the contact ring groove and a second one of the portions is formed below the contact ring groove.