Patent ID: 8790095

Claim:
An electric pump unit comprising: a unit housing; a bearing unit provided within the unit housing; a rotary portion comprising: a pump driving motor shaft supported by the bearing unit such that an axial position of a center of gravity of the rotary portion falls within an axial range of the bearing unit; and a motor rotor comprising: a disc portion which extends radially outwards from an axial end portion of the motor shaft; and a cylindrical portion which extends from an outer circumferential portion of the disc portion towards an other axial end portion of the motor shaft and surrounds an outer circumference of the bearing unit; and a motor stator fixed to the unit housing, wherein a small diameter cylindrical portion is formed on the unit housing so as to extend into an inside of the unit housing, wherein a portion of the bearing unit is provided inside the small diameter cylindrical portion, wherein the unit housing comprises: a cylindrical motor housing; and a pump housing coupled to an end of the motor housing, wherein the small diameter cylindrical portion is formed on the pump housing so as to extend into an inside of the motor housing, and wherein the motor stator is provided on an inner circumference of the motor housing.