Centrifugal pump impeller

Abstract

An impeller includes an impeller body in which an internal flow path and a recessed section are formed; a lid covering an opening of the recessed section; and a balance weight arranged between the impeller body and the lid. The lid is attached and fixed to the impeller body through an engagement section. Holding sections for the balance weight are formed in a back-side surface of the lid. When attaching and fixing the lid to the impeller body, the balance weight is sandwiched between the holding section of the lid and the impeller body to be fixed.

1 . A centrifugal pump impeller, comprising:
 an impeller body having a substantially cylindrical shape with first and second end surfaces facing each other in a cylindrical axis direction, and with a circumferential surface interposed between the first and second end surfaces; and including an internal flow path which connects between an inlet opening in the first end surface and an outlet opening in the circumferential surface, and a recessed section which opens in the second end surface, and which is recessed in the cylindrical axis direction in the second end surface;   a lid which is attached to the second end surface of the impeller body, and which covers the opening of the recessed section so that the second end surface of the impeller body defines a flat surface; and   a balance weight arranged between the impeller body and the lid,   wherein the lid is attached and fixed to the impeller body through an engagement section, and holding sections of the balance weight are formed in a back-side surface; and,   when the lid is attached and fixed to the impeller body, the balance weight is sandwiched between the holding section of the lid and the impeller body, and is fixed by the holding section of the lid and the impeller body.   
     
     
         2 . The centrifugal pump impeller of  claim 1 , wherein
 the engagement section includes engagement grooves formed in the impeller body or the lid; and engagement claws which are formed in the lid or the impeller body, and which are engaged with the engagement grooves by elastically deforming when attaching the lid to the impeller body.   
     
     
         3 . The centrifugal pump impeller of  claim 1 , wherein
 a plurality of pins are formed so as to protrude from the back-side surface of the lid; and   a plurality of pinholes into which the pins are fitted are formed so as to open in the second end surface of the impeller body.   
     
     
         4 . The centrifugal pump impeller of  claim 3 , wherein
 each of the pinholes is formed in a boss section provided in the second end surface of the impeller body;   a plurality of protrusions are formed with spacing in a circumferential direction in a circumferential surface of the boss section;   fitting holes which have a larger diameter than that of the boss section, and which have a smaller diameter than that of a circle defined by connecting tip ends of the plurality of protrusions are formed in the balance weight, and, in order to fix the balance weight to the impeller body, the fitting holes of the balance weight are fitted onto the boss sections with the protrusions being pressed against the boss sections; and   the holding section of the lid is formed in circular shape so as to surround the pin, and holds the balance weight in a section around the fitting hole.   
     
     
         5 . The centrifugal pump impeller of  claim 4 , wherein
 a plurality of reinforcement ribs extending in a radial direction are formed inside the recessed section of the impeller body, and an end surface of the reinforcement rib in the cylindrical axis direction is a mounting surface on which the balance weight is mounted; and   the boss section is integrally formed with the reinforcement rib in the mounting surface of the reinforcement rib.