Patent Application
20050104462
The present invention relates to a drum type washing machine, and more particularly, to a brushless DC motor for driving a drum type washing machine.
Generally, the drum type washing method performs the washing using a frictional force between the laundry and the drum rotated by driving force of a motor in a state where detergent, washing water and laundry are accommodated in the drum. The aforementioned drum type washing method has some advantages of no damaging the laundry, preventing tangle of the laundry, and providing an effect of beating and rubbing the laundry.
One example of such a direct-coupled drum type washing machine will now be described in brief with reference to FIGS. 1 to 4.
As shown in
A slot 11 is mounted on a front and rear end of the drum shaft 17, respectively, and the tub 3 is provided at a center portion of a rear wall thereof with a slot housing 15 for supporting the slot 11. A supporting bracket 16 is fixed to the rear wall of the tub 3, and a stator 30 which is a part of a direct-coupled motor is fastened to the supporting bracket 16 by means of a plurality of bolts 19.
The stator 30 includes, as shown in
Besides the stator 30, the motor 20 includes a rotor 40 shown in
The cabinet 5 is provided at a front side thereof with a door 1, and a gasket 2 is installed between the door 1 and the tub 3. A hanging spring 4 for supporting the tub 3 is provided between an inside of the upper surface of the cabinet 5 and an upper side of the circumference of the tub 3, while a friction damper 10 for attenuating vibration generated from the tub 3 during the spin cycle is provided between an inside of the lower surface of the cabinet 5 and a lower side of the circumference of the tub 3.
According to the conventional direct-coupled drum type washing machine constructed as described above, the rotor 40 is rotated by the interaction of an electromagnet formed by supplying a power to the stator 30 and a permanent magnet 41 attached to the inside of the rotor 40, and the force transferred to the drum shaft 17 allows the drum 9 to rotate, thereby performing washing and drying.
However, the conventional direct-coupled drum type washing machine has a problem in that noise is produced due to air friction between the rotor 40 and the stator 30.
Specifically, if the rotor 40 is rotated at a high speed, rapid air flow happens through a clearance 21 between the stator 30 and the rotor 40, while the air between the stator 30 and the slot 33 remains stationary. Therefore, there is generated a pressure difference between both airs, so that the air between the slots 33 is introduced into the clearance 21 and thus collides with the air flowing through the clearance 21 to generate an explosive sound. At that time, if a frequency of the explosive sound is identical with a natural frequency of the rotor 40 or the stator 30, a resonant sound is generated, so that abhorring sound is amplified. In particular, upon drying, the rotating speed of the rotor 40 becomes more rapid, so that more rapid air flow is formed through the clearance 21 to generate more dominant explosive sound and resonant sound.
In addition, upon driving the motor 20, since the polarity of each slot 33 is changed at a very high speed, the slot 33 itself vibrates and thus resonance is generated to amplify the noise.
Accordingly, the present invention is directed to a brushless motor for use in a drum type washing machine that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a brushless motor, for use in a drum type washing machine, capable of suppressing noise generated during the operation of the motor.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, there is provided a motor for use in a washing machine, the motor comprising: a stator fixed to a rear surface of a tub, and having a plurality of slots wound with a coil; a rotor provided at an outside of the stator together with a permanent magnet, and directly coupled to a washing drum installed inside the tub by a driving shaft; and isolating means for isolating a clearance between the stator and the rotor such that the stator and the rotor do not communicate with each other.
The isolating means includes a shield plate for shielding a space formed between the slots.
Preferably, the shield plate is a unitary piece enclosing all surfaces of the slots facing the permanent magnet to fully close the space between the slots, or is a plurality of unit pieces, each attached to the surface of the adjacent slot facing the permanent magnet to separately close the space between the slots.
Preferably, the shield plate is made of non-magnetic material, and is made of a non-adhesive film or an adhesive tape. The film or tape is made of heat-shrink resin material.
Preferably, the isolating means further includes an auxiliary shield plate for closing the space between the permanent magnets.
The auxiliary shield plate is a unitary piece fully enclosing a surface of the permanent magnet facing the slot to entirely close the space between the permanent magnet, or is a plurality of unit pieces each attached to a surface of the adjacent permanent magnet facing the slot to separately close the space between the permanent magnets.
On the other hand, the isolating means includes a plug member for filling a space between the slots, and the auxiliary shield plate is made of non-magnetic material.
The plug member is a unitary piece filling the space between the slot at once, and preferably includes: a hub seated on an upper surface of a frame of the stator; a coupling rib formed at the hub corresponding to the coupling rib for fixing the stator to the tub; and a plurality of tips formed at the hub at a regular interval, each of which is inserted into the space between the slots. The plug member further includes a plurality of reinforcing ribs formed at the hub for reinforcing strength thereof.
The plug member is a plurality of unit pieces, each separately filling the space between the slots, and preferably, is a plurality of tips, each inserted into the space between the slots.
According to the plug member of unitary or separate member, the tip is adapted to fill the entire spaces formed between the slots, and a longitudinal section of the tip has an approximately rectangular shape. The tip is adapted to partially fill the space formed between the slots. A longitudinal section of the tip has an approximately triangular shape.
Preferably, the tip has a hollow portion or recessed groove extended from an upper surface or a lower surface thereof.
The isolating means further includes an auxiliary plug member filling the space between the permanent magnets.
The auxiliary plug member is a unitary piece filling the space between the permanent magnet at one, or is a plurality of unit pieces closing separately the space between the permanent magnet.
According to the present invention, the clearance between the stator and the rotor is isolated from the space between the stator and the rotor, so that it prevents the collision of the air of different flowing speed to reduce the noise.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:
a is a perspective view of a plug member of a motor according to a second embodiment of the present invention;
b is a rear perspective view of
a is a plan view of
b is a cross sectional view taken along a line II-II in
a is a perspective view of an alternative view of a plug member according to a second embodiment of the present invention;
b is a rear perspective view of
a is a plan view of
b is a cross sectional view taken along a ling III-III in
Reference will now be made in detail to first and second preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the embodiments, like parts are shown by corresponding reference numerals throughout the drawings, and additive explanation thereof will be omitted.
The first embodiment of the present invention will now be described in detail with reference to FIGS. 5 to 9.
As shown in drawings, a motor 20 for use in a washing machine according to the first embodiment generally includes a stator 30 fixed to a rear surface of a tub 3, and a rotor 40 provided outside the stator at a predetermined clearance 21. The motor 20 of the present invention further includes an isolating member for isolating the clearance 21 between the stator 30 and the rotor 40.
The stator 30 is provided with a plurality of slots 33, which are radially disposed, and about which coil 33a is wound. The rotor 40 has a plurality of permanent magnets 41 enclosing the slots 33, and is directly coupled to a washing drum 9 installed inside the tube 3 by means of a driving shaft 17. Accordingly, the clearance 21 is substantially formed between the slot 33 and a permanent magnet 41. Also, the isolating member isolates the clearance 21, so that the clearance 21 does not communicate with the stator 30 and the rotor 40. In the motor 20 of the present invention, since the stator 30 and the rotor 40 are identical in their structures to those of the conventional motor described previously with reference to FIGS. 1 to 4, the isolating member will now be described in detail.
The isolating member includes shield plates 50 and 51 for shielding a space 34 between the slots of the stator 30.
As shown in
As shown in
When power is applied to the motor 20, if the shield plates 50 and 51 are magnetized, the operation of the motor may be hindered. In order to prevent the above problem, it is preferable to manufacture the shield plate with non-magnetic material. In other words, the shield plates 50 and 51 may have any one of a non-adhesive flexible film and an adhesive tape.
In case of employing the film, the shield plate 50 of unitary piece may be forcibly fitted in the radially outer end surfaces of the slot 33, while the shield plate 51 of unit piece has to be attached by use of separate adhesive. In addition, in case of employing the adhesive tape, the shield plates 50 and 51 may be easily attached to the radially outer end surfaces of the slot 33.
In these cases, the shield plates 50 and 51 play a role in holding the slot 33 not to be vibrated, as well as a role in closing the space 34. In particular, in case that the film or tape is made of heat-shrink resin material, the shield plates 50 and 51 is shrunk by heat generated from the operation of the motor 20, thereby more firmly holding the slots 33.
Since there is a space 42 between the permanent magnets 41 of the rotor 40 even through it is minute, the isolating member further includes an auxiliary shield plate 60 for closing the space 42 between the permanent magnets 41, as shown in
The auxiliary shield plate 60 may be a plurality of unit pieces, which are attached to the surfaces of two adjacent permanent magnets facing the slot 33, respectively, and separately close the space 42 between the permanent magnets 41, as shown in
Preferably, the auxiliary shield plate 60 is made of non-magnetic material to prevent the operation of the motor 20 from being hindered. In this case, the auxiliary shield plate 60 may be either a non-adhesive flexible film or an adhesive tape. More preferably, the film or tape is made of heat-shrink material.
In the first embodiment, the shield plates 50 and 51 and the auxiliary shield plate 60 have a thin thickness enough to prevent the interference between the rotor 40 and the stator 30, and although it is shown in the drawings that the shield plates 50 and 51 and the auxiliary shield plate 60 are made of transparent material, they may be made of semi-transparent or opaque material.
The operation of the motor according to the first embodiment of the present invention will now be described.
If the rotor 40 is rotated at a high speed, rapid air flow is formed through the clearance 21 between the stator 30 and the rotor 40 to lower the pressure therebetween, while since the air in the spaces 34 between the slots 33 remains stationary, the air pressure in the spaces 34 becomes relatively higher compared with that between the clearances.
During the operation of the motor 20, the shield plates 50 and 51 close the space 34, thereby isolating the clearance 21 from the space 34. Specifically, the shield plates 50 and 51 prevent the communication between the space 34 and the clearance 21. Accordingly, in spite of the pressure difference, the air remaining stationary in the space 34 does not flow into the clearance 21, and thus does not collide with the air flowing rapidly into the clearance 21. As a result, explosive sound or resonant sound due to the collision or friction of the airs in the clearance 21 and the space 34 is prevented. In addition, the space 42 between the permanent magnets 41 is closed by the auxiliary shield plate 60 although it is minute, so that the clearance 21 is completely isolated from the spaces 34 and 42. Accordingly, the occurrence of noise may be remarkably reduced during the operation of the motor.
Meanwhile, when the motor 20 is driven, the polarity of each of the slots 33 is changed at a high speed, so that the slot 33 that itself vibrates and thus resonance may be generated. The shield plates 50 and 51 of the present invention fix securely the slot 33, thereby preventing noise from being generated due to the vibration of the slot. In addition, the auxiliary plate 60 can prevent the vibration of the permanent magnet 41.
The second embodiment of the present invention will now be described in detail with reference to
A motor 20 for use in a washing machine according to the second embodiment generally includes a stator 30 fixed to a rear surface of a tub 3, a rotor 40 provided outside the stator 30 at a predetermined clearance 21, and an isolating member for isolating the clearance 21 between the stator 30 and the rotor 40. Since the stator 30 and rotor 40 are substantially identical in their structures to those of the first embodiment, their detailed description is omitted and accordingly detail description on the isolating member is given below.
According to the second embodiment of the present invention, the isolating member includes a plug member 70 filling a space 34 between the stator 30 and the slot 33.
The plug member 70 may be a unitary piece filling the spaces between the respective slots 33 at once, as shown in accompanying drawings. Preferably, the plug member 70 is made of non-magnetic material to prevent an electrical interference with the stator 30. Specifically, as shown in
The hub 71 has the same shape as the frame 31. The rib 72 is integrally protruded from an inner periphery of the hub 71 so as to correspond to the coupling rib 32 for fixing the stator 30 to the tub 3, and includes a coupling hole 72a with a desired size. The reinforcing ribs 74a and 74b are substantially formed at a rear surface of the hub 71, and are formed along a radial and circumferential direction, respectively, as apparently shown in
The tips 73 are integrally formed along an outer periphery of the hub 71, and are inserted into each space between the slots 33, respectively. According to the second embodiment of the present invention, the tips 73 may be formed to fully fill the space 34 between the slots 33. In this case, the longitudinal section of the tip 73 has an approximately rectangular shape, as shown in
Further, since the tip 73 may have a hollow portion or a recessed groove 73a extended from an upper or lower surface as shown in
Furthermore, since the tip 73 having the hollow portion or recessed groove 73a is slightly elastic, it may be forcibly fitted between the slots 33, so that the tip 73 fixes the slot 33 so as not to vibrate during the operation of the motor.
A process of assembling the plug member 70 and the stator 30 will now be described.
The plug member 70 is fixed to the rear wall of the tub 3 together with the stator 30 after the stator 30 and plug member 70 have been assembled. Specifically, in state where the coupling rib 32 of the stator is matched with the coupling rib 72 of the plug member 70, the tip 43 is inserted between the slots 33. As a result, the coupling hole 32a of the coupling rib 32 is aligned with the coupling hole 72a of the coupling rib 72, and the coupling member 19 penetrates through the coupling holes 32a and 72a to be coupled to the rear wall of the tub 3, so that assembling process of the stator 30 and the plug member 70 is completed.
Although not shown in the accompanying drawings, the plug member may consist of a plurality of unit pieces separately filling each space 34 between the-slots 33. The plug member may be a plurality of tips, each being inserted into the space 34, and the tip may be manufactured in a structure having some modules filling the spaces 34 every certain area in a circumferential direction of the stator 30. Such the plug member provides an effect of reducing material consumption, and each tip has the same characteristic as the tip 73 described with reference to
On the other hand, the isolating member preferably further includes an auxiliary plug member filling the space 42 between the permanent magnets 41 so as to completely isolate the clearance 21 between the stator 30 and the rotor 40. The auxiliary plug member 80 may be a plurality of unit pieces separately closing the spaces 42, as shown in
The auxiliary plug members commonly include tips inserted into the spaces 42, and it can be understood that these tips have the same characteristic as the aforementioned tip 73. The tip is formed to fully or partially fill the space 42 between the permanent magnets 41. The tip may have a hollow portion or a recessed groove, and is forcibly fitted between the permanent magnets 41.
The operation of the motor according to the second embodiment of the present invention will now be described.
If the rotor 40 is rotated at a high speed, rapid air flow is formed through the clearance 21 between the stator 30 and the rotor 40 to lower the pressure therebetween, while since the air in the spaces 34 between the slots 33 remains stationary, the air pressure in the spaces 34 becomes relatively higher compared with that between the clearances.
During the operation of the motor 20, the plug member 70 fills the space 34, thereby isolating the clearance 21 from the space 34. Here, in case the plug member 70 fills the entire spaces 34, the space 34 substantially disappears, so that it becomes impossible to communicate the space 34 with the clearance 21. Accordingly, the noise generated due to the rapid air flow in the clearance 21 is basically prevented. In addition, in case the space 34 is partially filled with the plug member 70, the tip 73 is formed to close the space 34, so that the space 34 is not communicated with the clearance 21. Accordingly, the air flow from the space 34 to the clearance 21 is prevented, and thus the noise generation due to the air collision is also prevented. The auxiliary plug member 80 fills or closes the space 42 between the permanent magnets 41 to effectively reduce the noise generated during the operation of the motor 20.
Meanwhile, the plug member 70 and the auxiliary plug member 80 are forcibly fitted between the slot 33 and the permanent magnet 41, thereby holding the slot 33 and the permanent magnet 41 and thus preventing noise such as resonance sound from being generated due to the vibration of the slot 33 and the permanent magnet 41.
While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.
Industrial Applicability
With the drum type washing machine of the present invention, the space between the slot and the permanent magnet is closed or filled by the shield plate/auxiliary shield plate or the plug member/auxiliary plug member to isolate the clearance between the stator and the rotor. Accordingly, the space between the slot and the permanent magnet is not communicated with the clearance, thereby substantially preventing the air flow between the space and the clearance. In addition, the slot and the permanent magnet are fixed by the shield plate/auxiliary shield plate or the plug member/auxiliary plug member so as to prevent the vibration thereof.
Resultantly, the present invention prevents explosive sound due to the air collision and the resonance sound generated during the operation of the motor, thereby improving the confidence of consumers on the product.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2001-17445 | Apr 2001 | KR | national |
| 2001-23388 | Apr 2003 | KR | national |
