Impeller, centrifugal pump and electric pump

An electronic pump, comprising a shaft, a rotor assembly and a stator assembly, wherein the rotor assembly comprises an impeller and a rotor, the rotor comprises a permanent magnet, the impeller comprises:

• an upper plate,
• blades, and
• a lower plate,
• wherein the blades are arranged between the upper plate and lower plate, and the upper plate comprises an upper surface and a lower surface, and the blades are fixedly connected to the lower surface of the upper plate, the blades comprise first blades,
• at least one arc, or a combination of at least one arc and at least one plane,
• the first blades are uniformly distributed on the upper plate, each of the first blades comprises a first side, a second side, a first head and a first tail, the first head is closer to a center of the impeller than the first tail,
• the first side is concave, and the second side is convex, a first connecting portion is defined between the first tail and the first side, a second connecting portion is defined between the first tail and the second side, the second connecting portion is arranged closer to an outer edge of the upper plate than the first head or to be flush with the outer edge of the upper plate, the outer edge of the upper plate is defined as a first circumference, a diameter of the first circumference is defined as a first diameter, the first side has no intersection with the outer edge of the upper plate, a distance of the first connecting portion from the outer edge of the upper plate is greater than the distance of the second connecting portion from the outer edge of the upper plate, and an extending line of the second side is intersected with the outer edge of the upper plate or the second side is intersected with the outer edge of the upper plate,
• in the direction from the lower surface to the upper surface of the upper plate along an axis of the impeller, an intersection of an extending line of the first side with the outer edge of the upper plate is defined as a first intersection, an intersection of the extending line of the second side with the outer edge of the upper plate or the second side with the outer edge of the upper plate is defined as a second intersection,
• the first side comprises a first arc close to an center of the impeller and a second arc away from the center of the impeller, the first arc and the second arc have different curvatures;
• the first side comprises a connecting point or a connecting segment;
• the first arc and the second arc are connected and tangential to each other at the connecting point, or are connected and tangential to each other at the connecting segment;
• the first tail comprises a first point and a second point,
• the first point is located on an arc, between the first intersection and the second intersection, of the first circumference, or is arranged toward the arc, between the first intersection and the second intersection, of the first circumference, and the first point is not coincident with the first intersection;
• a first borderline is defined, and the first borderline is part of a tangency which is made at the first point to the first circumference, and the first point is connected to the connecting point to define a second borderline, or the first point is connected to a connection point between the connecting segment and the second arc to define the second borderline, and
• the second point is located between the first borderline and the second borderline, and
• an included angle between the first borderline and the second borderline is greater than 90 degree,
• wherein the first tail comprises an inclined portion, in the direction from the lower surface to the upper surface of the upper plate along the axis of the impeller, the inclined portion comprises the first point and the second point, and a connecting line of the first point and the second point is located between the first borderline and the second borderline,
• wherein the blades further comprise second blades, and each of the second blades comprises at least one arc, the second blades are distributed uniformly along the circumference of the upper plate, the number of the first blades is same as the number of the second blades, and the first blades and the second blades are arranged alternatively at intervals along a circumferential direction of the upper plate, each of the second blades comprises a second head and a second tail, the second head is arranged closer to the center of the impeller than the second tail, the distance of the second head from the center of the impeller ranges from 0.3 to 0.35 times of the first diameter.