Variable water pump

The invention discloses a variable water pump which comprises a pump body, a pump shaft is arranged on the pump body, a sleeve is connected to the pump shaft in a sleeving mode, a plurality of impellers are arranged on the sleeve, inner blades are connected to the bottom of the sleeve in a sleeving mode, the inner blades correspond to the impellers in a one-to-one mode, the inner blades are made of bimetal, and when the temperature of water flow flowing through the impellers rises, the inner blades tilt upwards; the inner blades are made of bimetal, so that the effect height of the impeller is reduced when the temperature of water flowing through the impeller rises under the condition that the rotating speed of the pump shaft is not changed, the flow speed of the water flowing through the impeller is reduced, the speed of cooling water passing through the motor is reduced, the motor can be rapidly heated, and the service life of the motor is prolonged. And the temperature of the expected power of the motor is