Centrifugal pump and method for manufacturing the same

Abstract

A centrifugal pump is provided, which includes a rotor assembly, the rotor assembly includes an impeller including multiple blades and a blade fixing portion, the blades and the blade fixing portion are integrally formed by injection molding, and the blades are circumferentially distributed at equal intervals along the blade fixing portion. The blade includes a first side, a second side, a blade top portion and a blade root portion, and the blade root portion and the blade fixing portion are fixed by injection molding. The blade top portion is a cantilever end of the blade, and the first side and the second side are arranged between the blade root portion and the blade top portion. The rotor assembly arranged in such manner can improve the hydraulic efficiency and lift of the centrifugal pump.

1 .- 10 . (canceled) 
     
     
         11 . A method for manufacturing a centrifugal pump, wherein the centrifugal pump comprises a rotor assembly, the rotor assembly comprises an injection molded body and a shaft sleeve, the injection molded body comprises an impeller, the impeller comprises blades and a blade fixing portion, the rotor assembly is formed by injection molding, and the manufacturing of the rotor assembly comprises the following steps:
 fixing the shaft sleeve to a rotor assembly mould, wherein the rotor assembly mould is configured to form the injection molded body of the rotor assembly, and the shaft sleeve comprises a shaft sleeve inner cavity, wherein the step of fixing the shaft sleeve to the rotor assembly mould comprises: sleeving the shaft sleeve on a fixing shaft having a shape matching with a shape of the shaft sleeve inner cavity, fixedly arranging the fixing shaft to the rotor assembly mould, and arranging the fixing shaft in an inner cavity of the rotor assembly mould;   forming the injection molded body of the rotor assembly by injection molding, comprising: injection molding a mixed material of a plastic and a magnetic powder into the inner cavity of the rotor assembly mould, and cooling and solidifying to form the injection molded body of the rotor assembly; and   demolding, comprising: stripping the rotor assembly from the mould by removing the mould up and down, wherein:   the injection molded body of the rotor assembly comprises an impeller, the impeller comprises blades and a blade fixing portion, the blades and the blade fixing portion are fixed by injection molding, the blade comprises a first side, a second side, a connection side and a blade top portion, and the first side and the second side are connected by the connection side and the blade top portion;   the first side comprises a first convex portion and a first concave portion, the first convex portion and the first concave portion are smoothly connected, the second side comprises a second convex portion and a second concave portion, and the second convex portion and the second concave portion are smoothly connected;   a blade cross section is defined by cutting each of the blades via the hypothetical cylinder surface, the blade cross section comprises a first intersecting line, a second intersecting line, a third intersecting line and a fourth intersecting line, wherein the first intersecting line is an intersecting line defined by the hypothetical cylinder surface intersecting with the first side, the second intersecting line is an intersecting line defined by the hypothetical cylinder surface intersecting with the second side, the third intersecting line is an intersecting line defined by the hypothetical cylinder surface intersecting with the blade top portion, and the fourth intersecting line is an intersecting line defined by the hypothetical cylinder surface intersecting with the blade root portion, and a middle line is a straight line passing through a middle point of the third intersecting line and parallel to the central shaft of the impeller; and   a height of the blade in the blade cross section is defined as a distance from the fourth intersecting line to, an intersection between, the first intersecting line or the second intersecting line, and a line parallel to the fourth intersecting line, in the blade cross section at a portion with a first height, a distance from the first intersecting line to the middle line is a first distance, and a distance from the second intersecting line to the middle line is a second distance, and at a portion with a second height, a distance from the first intersecting line to the middle line is a third distance, and a distance from the second intersecting line to the middle line is a fourth distance, the following relationship is satisfied: in the case that the first height is greater than the second height, the first distance is less than or equal to the third distance, and the second distance is less than or equal to the fourth distance.   
     
     
         12 . The method for manufacturing the centrifugal pump according to  claim 11 , wherein in the step of forming the injection molded body of the rotor assembly by injection molding, at least two injection gates of the rotor assembly mould are provided, the injection gates are respectively arranged at an upper surface of the blade fixing portion between adjacent blades. 
     
     
         13 . The method for manufacturing the centrifugal pump according to  claim 11 , further comprising forming of the shaft sleeve, wherein the forming of the shaft sleeve comprises forming the shaft sleeve by injection molding with a shaft sleeve mould, wherein the shaft sleeve formed by injection molding is substantially of a cylindrical shape, the shaft sleeve comprises a shaft sleeve inner surface and a shaft sleeve outer surface, the shaft sleeve inner surface is matched with a shaft of the centrifugal pump, and the shaft sleeve outer surface is matched with the injection molded body. 
     
     
         14 . The method for manufacturing the centrifugal pump according to  claim 11 , wherein in the process of the demolding, the rotor assembly mould is provided with ejector structures, and the ejector structures are distributed at intervals in a circumference of the rotor. 
     
     
         15 . The method for manufacturing the centrifugal pump according to  claim 11 , wherein in the case that the rotor assembly mould has a plurality of mould cavities, each mould cavity is provided therein with a code number. 
     
     
         16 . The method for manufacturing the centrifugal pump according to  claim 11 , wherein the blade top portion comprises a proximal portion and a distal portion, the proximal portion is arranged to be closer to the central shaft of the impeller than the distal portion, and the blade top portion at a joint between the proximal portion and the distal portion is the highest point of the blade. 
     
     
         17 . The method for manufacturing the centrifugal pump according to  claim 16 , wherein in an axial direction of the rotor assembly, a thickness of the proximal portion of the blade is less than a thickness of the distal portion, a front end of the proximal portion and the blade fixing portion are formed by injection molding or fixed by injection molding, and a connecting point of the front end of the proximal portion and the blade fixing portion is located at a top portion of the blade fixing portion, or is located at a camber portion below the top portion of the blade fixing portion. 
     
     
         18 . The method for manufacturing the centrifugal pump according to  claim 17 , wherein the connection side and the second side are connected via a circular arc and form a smooth transition, and the circular arc is located at an outer edge of the impeller. 
     
     
         19 . The method for manufacturing the centrifugal pump according to  claim 16 , wherein a distance from the proximal portion to, a first plane perpendicular to the central shaft of the impeller, where a lower end of the blade fixing portion is located, is less than a height of the blade fixing portion. 
     
     
         20 . The method for manufacturing the centrifugal pump according to  claim 12 , wherein the rotor assembly comprises a rotor, the rotor contains a magnetic material, the rotor and the impeller are integrally formed by injection molding, an outer diameter of the rotor is greater than an outer diameter of the impeller, a connecting portion with a certain distance is provided between the outer diameter of the impeller and an outer surface of the rotor, and a stepped portion is formed between the connecting portion and the blade fixing portion.