Water Pump

A water pump, comprising:

• an upper casing and a lower casing that are coupled to each other to form an impeller accommodation space therein, and have an inlet formed above a central portion of the impeller accommodation space to communicate with the impeller accommodation space and to allow fluid to flow in, a discharge channel formed radially outside the impeller accommodation space to communicate with the impeller accommodation space, and an outlet connected to the discharge channel to discharge the fluid to an outside;
• an impeller that is rotatably accommodated in the impeller accommodation space;
• a rotor that is formed with a rotor accommodation part that protrudes downward from the central portion of the lower casing to form a rotor accommodation space therein, provided in the rotor accommodation part, and coupled to the impeller;
• and
• when the space within the inlet is referred to as a low-pressure space, and the space between the rotor and the rotor accommodation part is referred to as an intermediate-pressure space, a balance hole that is formed in a form of a through hole extending vertically on the rotor to allow the low-pressure space and the intermediate-pressure space to communicate with each other,
• wherein a labyrinth structure is formed in the intermediate-pressure space to suppress fluid flow.