Washing machine driving apparatus and washing machine including same

A washing machine driving apparatus comprises: a drive motor of a double rotor-double stator structure where the drive motor comprises an inner rotor and an outer rotor controllable independently by a double stator, and optionally generating inner rotor output and outer rotor output; a first inner shaft transferring the inner rotor output as a first input; a first outer shaft rotatably coupled to an outer periphery of the first inner shaft, and transferring the outer rotor output as a second input; a planetary gear unit where a gear ratio of a transmission output generated from a carrier is controlled by the second input applied to a ring gear through the first outer shaft, when the first input is applied to a sun gear through the first inner shaft; and a protection unit protecting the inner rotor where an outer peripheral portion of protection unit is supported by the double stator.

TECHNICAL FIELD

The present invention relates to a washing machine driving apparatus that may drive an inner rotor and an outer rotor independently, and a washing machine having the same.

BACKGROUND ART

As disclosed in Korean Patent Registration Publication No. 10-0548310 on Jan. 24, 2006, a conventional washing machine includes: an outer case forming an outer shape; an outer tub which is supported on an inside of the outer case and receives wash water therein; an inner tub which is rotatably accommodated in an inside of the outer tub and is used for both washing and dehydrating; a pulsator which is mounted relatively rotatably in an inside of the inner tub, to thus form a washing water flow; a drive motor for generating a driving force for rotating the inner tub and the pulsator; an inner tub rotating shaft which receives the driving force of the drive motor thereby rotating the inner tub; a pulsator rotating shaft which receives the driving force of the drive motor thereby rotating the pulsator; a sun gear which is connected to the drive motor and is connected to the pulsator rotating shaft; a plurality of planetary gears which are simultaneously engaged with both the sun gear and a ring gear; a carrier supporting the planetary gears so as to be rotated and revolved; and a clutch spring for controlling the rotation of the inner tub and the pulsator during washing or dehydrating.

The conventional washing machine disclosed in Korean Patent Registration Publication No. 10-0548310 has a planetary gear set including the sun gear, the ring gear, the planetary gears and the carrier, and reduces the rotational force of the drive motor, to then be transferred to the pulsator and the inner tub, and operates the clutch spring to selectively transmit power to the pulsator and the inner tub, to thus rotate only the pulsator during performing a washing stroke or to thus rotate both the pulsator and the inner tub simultaneously during performing a dehydrating stroke.

However, the conventional washing machine needs the planetary gear set and the clutch in order to selectively rotate the pulsator and the inner tub, to accordingly cause the configuration of the conventional washing machine to be complicated and the production cost thereof to increase.

Further, since the conventional washing machine is configured to have the planetary gear set and the clutch spring between the drive motor and the outer tub, the space occupied in the height direction of the washing machine is increased and thus the height of the washing machine increases. Otherwise, since the height of the inner tub should be reduced in an identical height of the washing machine, there is a problem that a washing capacity is reduced.

As a result, since the conventional washing machine has a structure that the pulsator and the inner tub may be rotated only in an identical direction, but may not be rotated in opposite directions to each other, there is a limit to improve performance of the washing machine.

In addition, since the conventional drive motor is configured in a state where the rotor is exposed to the outside, there is a fear that the interference with other parts may occur. As a result, a sufficient distance between the drive motor and the other part should be maintained to avoid interference to thus cause deterioration of space utilization.

Technical Problem

To solve the above problems or defects, it is an object of the present invention to provide a washing machine driving apparatus that may independently drive an inner rotor and an outer rotor, respectively, and that may be provided with a planetary gear set in one of the inner rotor and the outer rotor, to thereby shift a rotation speed of any one of the inner rotor and the outer rotor to thus enable torque conversion.

It is another object of the present invention to provide a washing machine driving apparatus capable of independently driving a pulsator and a washing tub, respectively, to thereby enable dual-power and mono-power implementations and form a variety of water flow patterns, and a washing machine having the same.

It is still another object of the present invention to provide a washing machine driving apparatus in which a protector protecting a rotor is provided with a stator to thus protect the rotating rotor, to thereby prevent interference between the rotor and other parts, to thus mount the other parts at a position close to the rotor, and to thereby improve space utilization, and a washing machine having the washing machine driving apparatus.

Technical Solution

To accomplish the above and other objects of the present invention, according to an aspect of the present invention, there is provided a washing machine driving apparatus comprising: a drive motor of a double rotor-double stator structure in which the drive motor comprises an inner rotor and an outer rotor that are controllable independently by a double stator, and optionally generates an inner rotor output and an outer rotor output; a first inner shaft that transfers the inner rotor output as a first input; a first outer shaft that is rotatably coupled to an outer periphery of the first inner shaft, and that transfers the outer rotor output as a second input; a planetary gear unit in which a gear ratio of a transmission output that is generated from a carrier is controlled by the second input is applied to a ring gear through the first outer shaft, when the first input is applied to a sun gear through the first inner shaft; and a protection unit for protecting the inner rotor in which an outer peripheral portion of protection unit is supported by the double stator.

Preferably but not necessarily, the outer rotor is connected to the first outer shaft, the inner rotor is connected to the first inner shaft, and the first inner shaft is rotatably mounted in an inside of the first outer shaft.

Preferably but not necessarily, the washing machine driving apparatus further comprises: a second outer shaft connected to the ring gear of the planetary gear set; and a second inner shaft connected to the carrier of the planetary gear set.

Preferably but not necessarily, the planetary gear set comprises: a ring gear connecting between the first outer shaft and the second outer shaft; a sun gear coupled to the first inner shaft; a plurality of planetary gears engaged to an outer surface of the sun gear and an inner surface of the ring gear; and a carrier to which the plurality of planetary gears are rotatably supported and that is connected to the second inner shaft.

Preferably but not necessarily, the first outer shaft is rotatably supported in two-way directions by a first bearing, and the second outer shaft is rotatably supported in two-way directions by a second bearing, wherein the first bearing is fixed to a stator support and the second bearing is mounted in a bearing housing.

Preferably but not necessarily, the inner rotor comprises: a first magnet which is disposed with a certain gap on an inner surface of the stator; a first back yoke which is disposed on a rear surface of the first magnet; and an inner rotor support to which the first magnet and the first back yoke are fixed.

Preferably but not necessarily, the outer rotor comprises: a second magnet which is disposed with a certain gap on an outer surface of the stator; a second back yoke which is disposed on a rear surface of the second magnet; and an outer rotor support to which the second magnet and the second back yoke are fixed, and a first connector connected to an outer surface of the outer shaft is formed on an inner surface of the outer rotor support and the first connector is disposed on an upper surface of the first bearing to prevent the first bearing from being seceded.

Preferably but not necessarily, a round per minute (RPM) of the second input which is applied to the ring gear is set to be smaller than that of the first input which is applied to the sun gear, and an output of the carrier is decelerated at the RPM of the first input. In this case, the first input has a high-speed, low-torque characteristic, and the output of the carrier has a low-speed high-torque characteristic, and is used for a laundry washing or rinsing stroke of the washing machine.

Preferably but not necessarily, the output of the ring gear is not shifted when a rotational direction and a RPM of the first input are the same as those of the second input. In this case, the first and second inputs have a high-speed, low-torque characteristic, respectively, and the output of the ring gear is a high-speed, low-torque characteristic, and is used for a dehydrating stroke of the washing machine.

Preferably but not necessarily, the double stator comprises: a stator core assembly around a number of stator cores of which first and second coils are wound to drive the inner rotor and the outer rotor; and a stator support that is formed integrally with the stator core assembly and on an outer circumferential portion of which an outer tub is fixed and on an inner circumferential portion of which the first outer shaft is rotatably supported.

Preferably but not necessarily, the stator support comprises: a core fixing portion in which the stator cores are mounted; a bearing fixing portion extending inwardly from the core fixing portion to thus fix a first bearing; a cover portion extending outwardly from the core fixing portion and that is formed in a cylindrical shape to thus secure the outer rotor; and an outer tub fixing portion extending outwardly from the cover portion and that is fixed to the outer tub.

Preferably but not necessarily, the protection unit is a protective cover that is located to cover a lower surface of the inner rotor, and whose edge is fixed to the stator support.

Preferably but not necessarily, the protection unit is a protector that is extended from the core fixing portion of the stator core support and covers an outer surface of the inner rotor.

Advantageous Effects

As described above, a washing machine driving apparatus according to the present invention may independently drive an inner rotor and an outer rotor, respectively, and may be provided with a planetary gear set in one of the inner rotor and the outer rotor, to thereby shift a rotation speed of any one of the inner rotor and the outer rotor to thus enable torque conversion.

In addition, a washing machine driving apparatus according to the present invention is configured to include a protector protecting a rotor provided with a stator to thus protect the rotating rotor, to thereby prevent interference between the rotor and other parts, to thus mount the other parts at a position close to the rotor, and to thereby improve space utilization.

In addition, a washing machine according to the present invention may be capable of independently driving a pulsator and a washing tub, respectively, to thereby enable dual-power and mono-power implementations and form a variety of water flow patterns.

In addition, a washing machine according to the present invention is configured to connect an outer rotor to a washing tub and connect an inner rotor to a pulsator, to thus cause a large-torque outer rotor to rotate the washing tub requiring a large-torque for starting, to thereby improve performance of the washing machine.

BEST MODE

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the process, the size and shape of the components illustrated in the drawings may be shown exaggerated for convenience and clarity of explanation. Further, by considering the configuration and operation of the present invention the specifically defined terms may be changed according to user's or operator's intention, or the custom. Definitions of these terms herein need to be made based on the contents across the whole application.

FIG. 1is a cross-sectional view of a washing machine according to an embodiment of the present invention, andFIG. 2is a cross-sectional view of a washing machine driving apparatus according to a first embodiment of the present invention.

Referring toFIG. 1, a washing machine according to an embodiment of the present invention includes: a case100forming an outer appearance; an outer tub110which is disposed in an inside of the case100and accommodating washing water; a washing tub120which is rotatably disposed inside the outer tub110to perform washing and dehydrating; a pulsator130which is rotatably disposed inside the washing tub120to form washing water flows; and a washing machine driving apparatus140which is mounted under the washing tub120and the outer tub120, to provide a driving force necessary for a washing stroke, a rinsing stroke, a detangle stroke, and a dehydrating stroke, for the washing tub120and the pulsator130, simultaneously or selectively.

As shown inFIG. 2, the washing machine driving apparatus140includes: a drive motor of a double rotor-double stator structure that is mounted on a lower portion of the outer tub110and that generates a high-speed, low-torque dual-power from the inner rotor40and the outer rotor50; and a planetary gear set70that is a torque converter that receives high-speed, low-torque first and second inputs that are provided by the inner rotor40and the outer rotor50of the drive motor and selectively shifts (or torque-coverts) so as to provide a first output to satisfy a low-speed, high-torque characteristic required for a washing stroke and a rinsing stroke and a second output to satisfy a high-speed, low-torque characteristic required for a dehydrating stroke.

First, the planetary gear set70is provided between the drive motor and the washing tub120, and receives the output of the inner rotor40of the drive motor through a first inner shaft30to then be transmitted to a sun gear74, and receives the output of the outer rotor50of the drive motor through a first outer shaft20to then be transmitted to a ring gear72.

Then, the high-speed, low-torque first input received through the first inner shaft30is shifted (or torque-converted) while passing through the sun gear74and planetary gears78of the planetary gear set70and then is transmitted to the second inner shaft32as the output of a carrier76, and the high-speed, low-torque second input transmitted to the ring gear72through the first outer shaft20is transmitted to the outer shaft22without the shift transmission (or torque conversion). The structure and operation of the planetary gear set70will be described below in detail.

The drive motor includes: a stator60on an outer side of which a first coil66is wound, and on an inner side of which a second coil68is wound; an outer rotor50that is arranged with a gap on an outer surface of the stator60and interacts with the first coil66; and an inner rotor40that is arranged with a gap on an inner surface of the stator60and interacts with the second coil66.

The outer rotor50is connected to outer shafts20and22, and the inner rotor40is connected to inner shafts30and32. The outer shafts20and22are formed of a hollow shape, and the inner shafts30and32are rotatably disposed inside the outer shafts20and22.

The outer shafts20and22are formed in a cylindrical shape so that the inner shafts30and32passes through the outer shafts20and22, and include: a first outer shaft20whose one end is connected to one end of the outer rotor50and whose other end is connected to one end of the ring gear72of the planetary gear set70; and a second outer shaft22whose one end is connected to one end of the outer rotor50and whose other end is connected to the other end of the ring gear72of the planetary gear set70.

Then, the inner shafts30and32include: a first inner shaft30that is connected to the inner rotor40and is connected to the sun gear74of the planetary gear set70; and a second inner shaft32that is connected to the inner rotor40and is connected to the carrier76of the planetary gear set70.

As shown inFIG. 3, the planetary gear set70includes: the ring gear72connecting between the first outer shaft20and the second outer shaft22; the sun gear74integrally coupled to the first inner shaft30; a plurality of planetary gears78engaged with an outer surface of the sun gear74and an inner surface of the ring gear72; and the carrier76to which the plurality of planetary gears78are rotatably supported and that is connected to the second inner shaft32.

The planetary gear set70is configured so that the first outer shaft20and the second outer shaft22are connected by the ring gear72and thus the rotational speed of the first outer shaft20is transferred to the second outer shaft22. Therefore, the rotational speed of the first outer shaft20is the same as that of the second outer shaft22.

In addition, the first inner shaft30is formed integrally with the sun gear74, and the second inner shaft32is spline-coupled or serration-coupled with the carrier76. The carrier76is rotatably supported to a rotational axis provided in the center of the planetary gears78. As a result, the rotational speed of the first inner shaft30is decelerated to then be transmitted to the second inner shaft32.

In this way, the inner shafts30and32are interconnected via the planetary gear set70to thus decelerate the rotational speed of the inner rotor40to then be transmitted to the pulsator130, to thereby increase the torque of the pulsator130and accordingly be applicable to a large-capacity washing machine.

A first sleeve bearing80is provided in a cylindrical form between an outer circumferential surface of the first inner shaft30and an inner circumferential surface of the first outer shaft20, to thus rotatably support the first inner shaft30.

A second sleeve bearing82is provided in a cylindrical form between an outer circumferential surface of the second outer shaft22and an inner circumferential surface of the second inner shaft32, to thus rotatably support the second inner shaft32.

A first link90to which an outer rotor support56of the outer rotor50is connected is formed on an outer surface of the first outer shaft20and a second link92to which an inner rotor support46of the inner rotor40is connected is formed on a lower end of the first inner shaft30.

The first link90and the second link92may be serration-coupled or spline-coupled through protrusions formed on the outer surfaces of the first outer shaft20and the first inner shaft30, or mutually key-coupled through key grooves formed on the outer surfaces of the first outer shaft20and the first inner shaft30.

Here, a second locking nut36is screwed and coupled at the lower end of the first inner shaft30, in which the second locking nut36prevents the departure of the inner rotor support46of the inner rotor50from the first inner shaft30.

A third link94is formed on the upper outer surface of the second outer shaft22in which the washing tub120is connected to the third link94, and a fourth link96is formed on the upper outer surface of the second inner shaft32in which the pulsator130is connected to the fourth link96.

The third link94and the fourth link96may be serration-coupled or spline-coupled through protrusions formed on the outer surfaces of the second outer shaft22and the second inner shaft32, or mutually key-coupled through key grooves formed on the outer surfaces of the second outer shaft22and the second inner shaft32.

A first seal220is mounted between the second outer shaft22and the second inner shaft32to prevent the washing water from leaking, and a second seal210is mounted between the second outer shaft22and a bearing housing10to prevent the washing water from leaking.

A first bearing26is disposed on the outer surface of the first outer shaft20, to thus rotatably support the first outer shaft20in two-way directions and a second bearing28is disposed on the outer surface of the second outer shaft22, to thus rotatably support the second outer shaft22in two-way directions.

The first bearing26is provided on a bearing support67integrally formed in a stator support68of the stator60, and the second bearing28is mounted in the bearing housing10.

The bearing housing10is formed of a metallic material, and includes: a second bearing mount portion12in which the second bearing28is mounted; a second seal fastener14that is extended outwardly from the second bearing mount portion12to thus fasten the second seal210; and an outer fixing portion16that is extended outwardly from the second seal fastener14to thus be fixed to the outer tub110.

The inner rotor40includes: a plurality of first magnets42that are disposed on the inner surface of the stator60with a certain gap; a first back yoke44disposed on the rear surfaces of the plurality of first magnets42; and an inner rotor support46that is integrally formed with the first magnets42and the first back yoke44by an insert molding method.

In addition, a metal plate48is integrally formed on an inner surface of the inner rotor support46by an insert molding method in which the metal plate48connects the inner rotor support46with the inner shafts30and32.

A flat plate made of a BMC (Bulk Molding Compound) material or a BMC powder sintered plate may be used on an inner surface of the inner rotor support46, in place of the metal plate48.

Here, the inner rotor support46is integrally formed with the plurality of first magnets42, the first back yoke44, and the metal plate48by molding a thermosetting resin, for example, a BMC (Bulk Molding Compound) molding material such as polyester. Thus, the inner rotor40may have waterproof performance, and shorten the manufacturing process.

Therefore, when the inner rotor40rotates, the inner shafts30and32are rotated, and the pulsator130that is connected to the inner shafts30and32is rotated.

Here, the pulsator130may be fully rotated by the torque of the inner rotor40due to the rotational torque that is not large.

Then, the outer rotor50includes: a plurality of second magnets52that are disposed on the outer surface of the stator60with a certain gap; a second back yoke54disposed on the rear surface of the plurality of the second magnets52; and an outer rotor support56that is integrally formed with the second magnets52and the second back yoke54by an insert molding method.

Here, the outer rotor support56is integrally formed with the plurality of second magnets52and the second back yoke54by molding a thermosetting resin, for example, a BMC (Bulk Molding Compound) molding material such as polyester.

The inner surface of the outer rotor support56is connected to the first link90of the first outer shaft20and the outer rotor support56is rotated with the first outer shaft20, and the second magnet52and the second back yoke54are fixed to the outer surface thereof.

Therefore, when the outer rotor50rotates, the outer shafts20and22are rotated, and the washing tub120associated with the outer shafts20and22is rotated.

The torque of the outer rotor50is larger than that of the inner rotor40. Then, a larger torque is needed in order to rotate the washing tub120, when compared with the torque needed to rotate the pulsator130.

In this way, the washing machine driving apparatus according to the embodiment is configured so that the outer rotor50having a large torque is connected to the washing tub120that requires a large torque, to thereby realize a high-capacity washing machine.

The stator60includes: a plurality of stator cores62that are arranged in an annular shape; non-magnetic bobbins64that are configured to wrap the outer circumferential surfaces of the plurality of stator cores62, respectively; a first coil66that is wound on one side of each of the stator cores62; a second coil68that is wound on the other side of each of the stator cores62; and a stator support270in which the plurality of stator cores62are arranged in an annular shape and that is fixed to the outer tub110.

The stator60applied for the embodiment of the present invention is configured to form a double stator that may the inner rotor40and the outer rotor50selectively or simultaneously, in correspondence to a drive signal, by applying the drive signal to the first coil66wound on one side of the stator cores62and the second coil68wound on the other side thereof selectively or simultaneously.

The stator support270is integrally formed with the stator cores62by an insert molding method after arranging the plurality of stator cores62at certain intervals in an annular form in the circumferential direction thereof in a mold.

In other words, the stator support270is molded by the insert molding method by molding a thermosetting resin, for example, a BMC (Bulk Molding Compound) molding material such as polyester. In this case, the plurality of stator cores62are arranged at certain intervals in an annular form in the circumferential direction thereof in a mold, and thus are integrally formed.

Other than the structure that the stator support270is integrally formed with the stator cores62by insert molding, the stator support270may be separately manufactured from the stator cores62and then coupled with the stator cores62by using bolts.

The stator support270includes: a core fixing portion272in which the stator cores62are mounted; a bearing fixing portion67extending inwardly from the core fixing portion272to thus fix a first bearing26; a cover portion274extending outwardly from the core fixing portion272and that is formed in a cylindrical shape to thus secure the outer rotor50; and an outer tub fixing portion276extending outwardly from the cover portion274and that is fixed to the outer tub110.

Thus, the cover portion274is formed in the stator support270and is arranged at a certain gap from an outer surface of the outer rotor50, to thus cause a separate motor cover to be unnecessary to protect the outer rotor50, to thereby reduce the number of parts, and to thus protect the outer rotor50to thereby prevent the outer rotor50from interfering with other parts.

Then, the stator support unit270is provided with a protective unit to prevent the rotating inner rotor40from interfering with other parts.

The protection unit according to one embodiment is covered on a lower surface of the inner rotor40, and is a protective cover400that is coupled to a lower surface of the stator support270.

The protective cover400is configured to have a disc shape that is formed to fit the shape of the inner rotor40, bolt coupling holes402are formed on a lower surface of the core fixing portion272of the stator support270, and edges of the protective cover400are coupled to the bolt coupling holes402.

A bent portion404that has been bent at right angles is formed on an edge of the protective cover400and the bent portion404is in contact with an outer surface of a protruding portion406on which the bolt coupling holes402of the stator support are formed.

In this way, the protective cover400is provided in the stator support270to thereby protect the inner rotor40, and thus it is possible to avoid interference between the inner rotor40and the other parts. As a result, utilization of space may be improved with no need to have a distance to avoid interference between the motor and other components.

FIG. 4shows a washing machine driving apparatus according to a second embodiment, in which a stator support has a structure different from that of the first embodiment.

The stator support500according to the second embodiment includes: a core fixing portion502in which a stator core62is mounted; a bearing fixing portion504that extends inwardly from the core fixing portion502and holds a first bearing26; a cover portion506extending outwardly from the core fixing portion502and formed in a cylindrical shape thereby protecting the outer rotor50; an outer tub fixing portion508extending outwardly from the cover portion506and fixed to the outer tub110; and a protective fence which extends from a lower surface of the core fixing portion502.

The protective fence according to the second embodiment includes a protector510that is formed in a cylindrical shape extending integrally from the core fixing portion502of the stator support500, or that is arranged at a predetermined interval in a circumferential direction of the inner rotor, and that is positioned to be wrapped around the outer surface of the inner rotor.

The protector510may have a structure that is formed in a circular form or protrudingly in the form of projections extending to a predetermined height in the core fixing portion502of the stator support500, and that is arranged at a predetermined interval in a circumferential direction of the core fixing portion502.

In addition, the protector510may employ any structure that extends integrally from a lower surface of the stator support500and that wraps an outer surface of the inner rotor40.

In this way, the protector510is arranged to extend integrally from a lower surface of the stator support500and to wrap an outer surface of the inner rotor40, to thus prevent the inner rotor40from interfering with other parts.

In this way, the protector510is integrally formed with the stator support500according to the second embodiment, and need not be provided with a protective cover to protect the inner rotor40separately, thereby reducing the number of parts.

As shown inFIGS. 5 to 7, the stator core62includes: a first tooth portion310around which the first coil66is wound; a second tooth portion312that is formed on the other side of the first tooth portion310and around which the second coil68is wound; a partition314for partitioning between the first tooth portion310and the second tooth portion312; and couplers320and322formed on both lateral ends of the partition314and interconnecting between the adjoining stator cores62.

Here, a first drive signal is applied to the first coil66and a second drive signal is applied to the second coil68. Accordingly, when the first drive signal is applied to only the first coil66, only the inner rotor40is rotated, when the second drive signal is applied to only the second coil68, only the outer rotor50is rotated, and when the first drive signal and the second drive signal are applied to the first coil66and second coil68, respectively, both the inner rotor40and outer rotor50are rotated.

A throughhole332is formed at the center of the partition314, to thus serve to prevent a first magnetic circuit formed by the first coil66and a second magnetic circuit formed by the second coil68from being interfered with each other. The throughhole332may be formed in a circular shape, but may be formed long in a slot type in the lateral direction of the partition314.

A first flange316is formed at the end of the first tooth portion310so as to be disposed to face the first magnets42and a second flange318is formed at the end of the second tooth portion312so as to be disposed to face the second magnets52.

The first flange316and the second flange318are formed to have inward and outward curved surfaces at predetermined curvatures, respectively, to correspond to the first magnet42of the inner rotor40and the second magnet52of the outer rotor50. Thus, the roundness of the inner circumferential surface and the outer circumferential surface of the stator core62is increased and thus certain magnetic gaps may be maintained between the inner circumferential surface of the stator60and the first magnet42and between the outer circumferential surface of the stator60and the second magnet52, respectively, although the inner circumferential surface and outer circumferential surface of the stator60are proximate to the first magnet42and the second magnet52.

The plurality of stator cores62should have a structure of being directly connected to each other so as to form a magnetic circuit. Thus, the couplers320and322of one stator core62have a structure of being directly connected to the couplers322and320of another adjacent stator core62so that the stator cores62may be energized.

As an example, these couplers320and322are configured so that a coupling protrusion322is protrudingly formed at one side of the partition314and a coupling groove320with which a coupling protrusion322of a neighboring stator core62is fitted and coupled is formed at the other side of the partition314. Thus, when the coupling protrusion322of one state core is fitted into and coupled with the coupling groove320of a neighboring stator core, the stator cores62are annularly arranged, and have a directly cross-linked structure that the stator cores62are directly connected with each other.

In addition to the above structure, the couplers have a structure that pinholes are formed at both end portions of the partition of each of the stator cores, and a pin member is fitted into and coupled with the pinholes of two stator cores at a state where the stator cores contact each other, to thereby employ a structure of connecting between the stator cores. Alternatively, the couplers may employ a method of caulking the stator cores by using a caulking member in a state where the stator cores contact each other.

The washing machine driving apparatus according to an embodiment of the present invention forms a first magnetic circuit L1between the inner rotor40and one side of the stator60where the first coil66is wound, and forms a second magnetic circuit L2between the outer rotor50and the other side of the stator60where the second coil68is wound, to thus form a pair of magnetic circuits each independent to each other. As a result, the inner rotor40and the outer rotor50may be respectively driven separately.

More specifically, the first magnetic circuit L1includes the first magnet42of the N-pole, the first tooth portion310on which the first coil66is wound, an inner part of the partition314, the first magnet42of the S-pole adjacent to the first magnet42of the N-pole, and the inner rotor support46.

In addition, the second magnetic circuit L2includes the second magnet52of the N-pole, the second teeth portion312facing the second magnet52of the N-pole and on which the second coil68is wound, an outer part of the partition314, the second magnet52of the S-pole, and the outer rotor support56.

The function of the washing machine driving apparatus according to an embodiment of the present invention will now be described.

The stator60that forms a double stator according to an embodiment of the present invention may drive the inner rotor40and the outer rotor50, selectively or simultaneously, by a drive signal that is applied to the first coil66and the second coil68, selectively or simultaneously.

The first and second outer shafts20and22associated with the planetary gear set70are rotatably supported in two-way directions by first and second bearings26and28in an outside of the first and second outer shafts20and22, and by sleeve bearings80and82in an inside of the first and second outer shafts20and22.

Since the planetary gear set70according to an embodiment of the present invention is rotatably supported in two-way directions as described above, a gear ratio of a transmission output generated from the carrier76in the planetary gear set70may be controlled by a second input applied to the ring gear72through the first outer shaft20, when a first input is applied to the sun gear74through the first inner shaft30.

When a round per minute (RPM) of the second input which is applied to the ring gear72is set to be smaller than that of the first input which is applied to the sun gear74, an output of the carrier76is decelerated at the RPM of the first input.

That is, when the first input has a high-speed, low-torque characteristic, the output of the carrier76has a low-speed high-torque characteristic, and is used for a laundry washing or rinsing stroke of the washing machine.

Further, when the direction of rotation of the second input is opposite to that of the first input, and the RPM of the second input is one quarter of the first input, the reduction in RPM of the first input from the carrier76is generated to the maximum output.

Further, the output of the ring gear72is not shifted when a rotational direction and a RPM of the first input are the same as those of the second input.

That is, when the first and second inputs have a high-speed, low-torque characteristic, respectively, the output of the ring gear72is a high-speed, low-torque characteristic, and is used for a dehydrating stroke of the washing machine.

Controlling the washing machine using the above-described washing machine driving apparatus will be described as follows.

First, when only the pulsator130is driven during a washing operation, and a drive signal is applied to the first coil66, the inner rotor40is rotated and the first inner shaft30connected to the inner rotor50is rotated. Then, the rotational speed of the inner rotor40is decelerated by the planetary gear set70coupled to the first inner shaft30to then be transmitted to the second inner shaft32, and thus the pulsator130connected to the second inner shaft32is rotated.

Thus, the rotational speed of the pulsator130is reduced and torque thereof is increased by the planetary gear set70. Accordingly, the washing machine driving apparatus according to the embodiment of the present invention may be applied to a large-capacity washing machine.

In addition, when only the washing tub120is driven to rotate, and a drive signal is applied to the second coil68, the outer rotor50is rotated by the magnetic circuit L2and the outer shafts20and22connected to the outer rotor50are rotated to rotate the washing tub120.

In this case, since the rotational force of the outer rotor50having a large torque is transmitted to the washing tub120, it is easy to rotate the washing tub120that requires a large torque. Therefore, it is possible to raise the capacity of the washing machine, and it is also possible to implement a large capacity washing machine.

Further, when both the pulsator130and the washing tub120are simultaneously rotated, during a dehydration stroke and a rinsing stroke, the drive signals are simultaneously applied to the first coil66and the second coil68, respectively. Then, the inner rotor40is rotated by the magnetic circuit L1, and thus the inner shafts30and32associated with the inner rotor40are rotated, to thereby rotate the pulsator130. Then, the outer rotor50is rotated by the magnetic circuit by L2, and thus the outer shafts20and22connected to the outer rotor50are rotated to thereby rotate the washing tub120.

In addition, when the pulsator130and the washing tub120are reversely rotated to each other during a detangle stroke or in order to remove laundry tangle such as laundry jam, drive signals are applied to the first coil66and the second coil68simultaneously, and the first drive signal applied to the first coil66and the second drive signal applied to the second coil68are each controlled independently, to thereby rotate the pulsator130and the washing tub120in opposite directions to each other while rotating the inner rotor40and the outer rotor50in opposite directions to each other.

In addition, the pulsator130and the washing tub120may be rotated with a time difference in an identical direction, to thus form a variety of wash water flows.

As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one of ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. Thus, the protective scope of the present invention is not defined within the detailed description thereof but is defined by the claims to be described later and the technical spirit of the present invention.

INDUSTRIAL APPLICABILITY

The present invention may be applied to a washing machine driving apparatus that may drive an inner rotor and an outer rotor independently, and a washing machine having the same.