Patent ID: 6514053
Filing Date: 2003-02-04
Classification: F04D

Abstract:
A motor-driven pump with a plurality of impellers, comprising:an electric motor including an output shaft, a motor frame rotatably supporting the output shaft while at least one end portion of the output shaft is protruded outward, and a rotation driving mechanism provided in the motor frame and rotating the output shaft in a predetermined direction when the mechanism is supplied with electric power; a pump housing provided on a side of the one end portion of the output shaft in the electric motor, having two fluid inlet port regions on a side near the electric motor and on a side away from the electric motor in a longitudinal direction of the output shaft, respectively, and having one fluid discharge port region between the two fluid inlet port regions; and an impeller unit including a pair of impellers having a partition wall concentrically fixed to the one end portion of the output shaft in an inner space of the pump housing, directing to the one fluid discharge port region, spreading outward in a radial direction of the output shaft and partitioning the inner space into a portion near the electric motor and a portion away from the electric motor, and a pair of blade means provided on both sides of the partition wall, respectively, the impeller unit moving fluid on the both sides of the partition wall from inside to outside in the radial direction along the pair of blade means of the pair of impellers by a centrifugal force in the inner space when the impeller unit is rotated by the output shaft of the electric motor in the predetermined direction, wherein a radial bearing rotatably supporting the other end portion of the output shaft is provided in an opposite portion to the pump housing in the motor frame of the electric motor; and another radial bearing rotatably supporting the one end portion of the output shaft is provided in a portion, located outward from the one end portion in the longitudinal direction of the output shaft, in the pump housing of the electric motor.