Structure of driving unit in drum type washing machine

A structure of a driving unit in a drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub disposed horizontal to the ground, or with an angle to the ground for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub for transmission of a driving force of a motor to the drum; bearings each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; a cup formed rotor having a rotor body of magnetic material and permanent magnets, the rotor body comprising a sidewall serving as a back yoke that forms a magnetic flux path and a rear wall formed as one unit with the sidewall to cover an outer circumference and a bottom of the stator, the permanent magnets fitted to a setting surface of an “L†shaped bent portion of the sidewall; and a connector connecting the rotor and the shaft for rotating the drum.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, and a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores; and a cup-formed rotor having a rotor body of magnetic material and permanent magnets, the rotor body comprising a side wall and a rear wall to cover an outer circumference and a bottom of the stator, the permanent magnets fitted to the side wall, wherein the rotor includes cooling fins each formed by cutting the rear wall in a ‘⊂’ form, and folding in a stator direction for cooling the stator.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, and a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores; a cup-formed rotor having a rotor body comprising a side wall and a rear wall to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall; and a connector connecting the rotor and the shaft, wherein the connector is formed of resin and is configured to couple to the shaft at a central portion of the connector, and a section of the connector parallel and adjacent to an axis of rotation of the connector is substantially in the shape of a trapezoid.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, and a plurality of coils, each wound around a respective one of the salient poles; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the rotor includes embossings on the rear wall of the rotor, disposed in a direction of a centrifugal force, for preventing the rotor from being distorted in a drying operation of the washing machine when the rotor rotates the drum containing laundry at a high speed.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward, a plurality of coils, each wound around a respective one of the salient poles, and a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores; and a cup-formed rotor having a rotor body comprising a side wall serving as a back-yoke that forms a magnetic flux path and a rear wall formed as one unit with the side wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to a setting surface of an “L†shaped bent portion of the side wall.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward, each with a fastening hole for fixing the stator to the bearing housing; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the stator fastening bosses are cylindrical protrusions from the bearing housing, each comprising a hole with a screw thread in a center thereof, and the stator is fastened to the bearing housing by bolting it at the holes with a screw thread through the fastening holes in the fastening ribs.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body of magnetic material and permanent magnets, the rotor body comprising a side wall serving as a back-yoke that forms a magnetic flux path and a rear wall to cover and outer circumference and a bottom of the stator, the permanent magnets fitted to the side wall, wherein the stator fastening bosses are cylindrical protrusions from the bearing housing, each comprising a hole with a screw thread in a center thereof, and the stator is fastened to the bearing housing by bolting it at the holes with a screw thread through the fastening holes in the fastening ribs.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall; and a connector connecting the rotor and the shaft, wherein the stator fastening bosses are cylindrical protrusions from the bearing housing.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the rotor includes cooling fins each formed by cutting the rear wall in a ‘⊂’ form, and folding in a stator direction for cooling the stator, and wherein the stator fastening bosses are cylindrical protrusions from the bearing housing.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal of the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the rotor includes embossings on the rear wall of the rotor for reinforcement of the rotor, and wherein the stator fastening bosses are cylindrical protrusions from the bearing housing.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, and a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores; and a cup-formed rotor having a rotor body of magnetic material and permanent magnets, the rotor body comprising a side wall serving as a back-yoke that forms a magnetic flux path and a rear wall to cover an outer circumference and a bottom of the stator, the permanent magnets fitted to the side wall, wherein the bearing housing extends up to an outer circumference of the tub, to be fixed to tub brackets fixed to an outer circumference of the tub at a rear portion of the tub.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub an disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the rub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall; and a connector connecting the rotor and the shaft, wherein the bearing housing extends up to an outer circumference of the tub, to be fixed to tub brackets fixed to an outer circumference of the tub at a rear portion of the tub.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the rotor includes cooling fins each formed by cutting the rear wall in a ‘⊂’ form, and folding in a stator direction for cooling the stator, and wherein the bearing housing extends up to an outer circumference of the rub, to be fixed to tub brackets fixed to an outer circumference of the tub at a rear portion of the tub.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the rotor includes embossings on the rear wall of the rotor for reinforcement of the rotor, and wherein the bearing housing extends up to an outer circumference of the tub, to be fixed to tub brackets fixed to an outer circumference of the tub at a rear portion of the tub.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the stator fastening bosses are cylindrical protrusions from the bearing housing.

A drum type washing machine, comprising:na tub for storing washing water; a drum of a metal rotatably mounted inside of the tub and disposed one of horizontal to the ground or with an angle to the ground, for accommodating laundry therein; a shaft connected, through the tub, to the drum mounted inside of the tub, for transmission of a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a bearing housing having a central portion and stator fastening bosses disposed at fixed intervals along a circumference of the central portion, for supporting the bearings; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; and a cup-formed rotor having a rotor body comprising a side wall and a rear wall, to cover an outer circumference and a bottom of the stator, and permanent magnets fitted to the side wall, wherein the bearing housing extends up to an outer circumference of the tub, to be fixed to the tub brackets fixed to an outer circumference of the tub at a rear portion of the tub.

A drum type washing machine, comprising:na tub configured to store washing water; a drum for accommodating laundry therein rotatably mounted inside of the tub; a shaft connected, through the tub, to the drum and configured to transmit a driving force of a motor to the drum; bearings, each fitted onto an outer circumference of the shaft for supporting the shaft; a stator having a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole that projects outward in a radial direction with respect to a central axis of the stator, a plurality of coils, each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame; a cup formed rotor having a rotor body and permanent magnets, the rotor body comprising a sidewall serving as a back yoke that forms a magnetic flux path, and a rear wall; and a connector configured to connect the rotor and the shaft.

In a washing machine including a tub having a rear side with a bottom wall, a rigid star carrier attached to the bottom wall of the tub and having a bearing sleeve, an at least approximately horizontally disposed shaft mounted in the bearing sleeve, and a laundry drum mounted on the shaft, a drive device to be mounted at the rear side of the tub for directly driving the shaft, comprising:na flat motor having a stator carrying part with exciting windings and rotor with magnetizable poles, wherein said stator carrying part and said rotor are connected to one another and, wherein that stator carrying part comprises a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame.

A drum type washing machine, comprising:nan outer cabinet; a water tub elastically supported in the outer cabinet; a drum type rotatable tub provided in the water tub to be rotated about a horizontal axis; a rotatable tub shaft mounted to the rotatable tub outside the cavity and extending outward from the central portion of the end plate of the rotatable tub; and a motor driving the rotatable tub via the rotatable tub shaft and including a rotor mounted on the other end of the rotatable tub shaft and a stator fixed in relation to the water tub and disposed inside the rotor, wherein the stator comprises a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame.

An apparatus for treating laundry, comprising:na drum; a substantially horizontal axle for rotatably mounting the drum; and a motor comprising a rotor comprising a predetermined number of permanent magnets and a stator including a plurality of magnetic cores formed by stacking magnetic laminations, each having a salient pole projected outward in a radial direction with respect to a central longitudinal axis of the stator, a plurality of coils each wound around a respective one of the salient poles, a frame of insulating material for covering top and bottom surfaces of a magnetic core assembly of the magnetic cores, and a plurality of fastening ribs projected inward in the radial direction, the fastening ribs formed as one unit with the frame.

A washing machine, comprising:nan outer tub; an inner tub rotatably mounted within the outer tub; a drive shaft attached to the inner tub; a stator having a coil; a rotor attached to the drive shaft and comprising a frame configured to cover at least a portion of the stator; and a bearing housing configured to be attached to the outer tub, the bearing housing having a central portion and including a recess configured to receive the stator, the recess comprising a plurality of step portions serially disposed in a radial direction, wherein stator fastening bosses are disposed at fixed intervals along a circumference of the central portion, the stator fastening bosses being configured for attachment of the stator thereto, wherein the central portion of the bearing housing comprises a plurality of radially extending ribs, and wherein the central portion of the bearing housing comprises a circular reinforcing rib that connects the stator fastening bosses.

A washing machine, comprising:nan outer tub; an inner tub rotatably mounted within the outer tub; a drive shaft attached directly to the inner tub; a motor, the motor comprising: a stator having a coil; and a rotor directly attached to the drive shaft and comprising a frame configured to cover at least a portion of the stator; and a bearing housing attached to the outer tub and the stator and comprising a central portion having at least one circular reinforcing rib and a plurality of arms that extend therefrom and including a recess configured to receive the stator, the recess comprising a plurality of step portions serially disposed in a radial direction.

A washing machine, comprising:nan outer tub; an inner tub rotatably mounted within the outer tub; a drive shaft attached to the inner tub; a stator having a coil; a rotor attached to the drive shaft and configured to cover at least a portion of the stator; and a bearing housing coupled to the stator and the outer tub, the bearing housing including a recess configured to receive the stator, the recess comprising a plurality of step portions serially disposed in a radial direction, and stator fastening bosses disposed along a circumference of a central portion thereof, wherein the bearing housing comprises a rib connecting the stator fastening bosses with each other.

A washing machine, comprising:nan outer tub; an inner tub rotatably mounted within the outer tub; a drive shaft attached to the inner tub; a stator having a coil; a rotor attached to the drive shaft and configured to cover at least a portion of the stator; and a connector coupled between the drive shaft and the rotor, and including a plurality of positioning projections, wherein the connector is formed of an electrically insulating material.

A washing machine, comprising:nan outer tub; an inner tub rotatably mounted within the outer tub; a drive shaft attached to the inner tub; a stator having a coil; a rotor attached to the drive shaft and configured to cover at least a portion of the stator; and a bearing housing coupled to the stator and the outer tub and including a recess configured to receive the stator, the recess comprising a plurality of step portions serially disposed in a radial direction.