Centrifugal pump apparatus

摘要

A centrifugal blood pump apparatus includes a plurality of permanent magnets (17) in an impeller (10) in a blood chamber (7), a plurality of coils (20) in a motor chamber (8), and a magnetic element (18) in each of the coils (20). The magnetic elements (18) are made shorter than the coils (20) to lower attractive force between the magnetic elements (18) and the permanent magnets (17) in the impeller (10), to set a large gap between the magnetic elements (18) and the permanent magnets (17). As a result, axial attractive force and negative rigidity can be lowered while required torque is satisfied.

主权项

1. A centrifugal pump apparatus including a housing having first and second chambers partitioned from each other by a dividing wall, an impeller rotatably provided in said first chamber along said dividing wall, for delivering fluid by centrifugal force during rotation, and a drive unit provided in said second chamber for driving said impeller to rotate, comprising:
a first magnetic element provided in one surface of said impeller; a second magnetic element provided in an inner wall of said first chamber facing the one surface of said impeller, for attracting said first magnetic element; and a plurality of third magnetic elements provided in an other surface of said impeller, arranged in a direction of rotation of said impeller, and attracted by said drive unit, wherein: said drive unit includes a plurality of coils provided to face said plurality of third magnetic elements, for generating a rotating magnetic field, a plurality of fourth magnetic elements provided in correspondence with said plurality of coils respectively and each inserted in the corresponding coil, each said fourth magnetic element is shorter than the corresponding coil in a direction of a central axis of said impeller, during rotation of said impeller, a first attractive force between said first and second magnetic elements and a second attractive force between said plurality of third magnetic elements and said plurality of fourth magnetic elements are balanced with each other substantially in a center of a movable range of said impeller in said first chamber, a first groove for hydrodynamic bearing is formed in one surface of said impeller or in the inner wall of said first chamber facing the one surface, a second groove for hydrodynamic bearing is formed in the other surface of said impeller or in said dividing wall facing the other surface, and each said fourth magnetic element includes a strip-shaped magnetic steel plate wound a plurality of times around a center line.