|Publication number||USRE42583 E1|
|Application number||US 10/853,764|
|Publication date||Aug 2, 2011|
|Filing date||May 26, 2004|
|Priority date||Jun 7, 1999|
|Also published as||CN1174537C, CN1276643A, US6396190|
|Publication number||10853764, 853764, US RE42583 E1, US RE42583E1, US-E1-RE42583, USRE42583 E1, USRE42583E1|
|Inventors||In Geun Ahn, Dong Beom Lee, Jong Chul Bang|
|Original Assignee||Lg Electronics Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (25), Referenced by (2), Classifications (27), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention relates to a washing machine, and more particularly, to a brushless motor for driving an inner tub or a pulsator in a washing machine.
2. Background of the Related Art
In general, the washing machine washes contaminated laundry clean by driving the inner tub or the pulsator by using a motor to circulate washing water having detergent contained therein.
That is, referring to
The operation of the aforementioned system will be explained.
Upon application of a power to the brushless motor 4, the rotor 20 of the motor rotates in one direction by a polarity difference from the stator 10 and a flow of magnetic flux along the back yoke 23, to rotate the support member 30 coupled to the lower frame 21 of the rotor 20. According to this, the shaft 5 coupled with the female serration 31 inside of the support member 30 receives the rotating force of the rotor 20 through the support member 30 to rotate the inner tub 1 coupled to the shaft 5, thereby facilitating washing of the laundry.
However, the related art brushless motor has the following various problems caused by the structure.
First, the general plastic injection molded lower frame 21 in the rotor 20 of the related art brushless motor 4 impedes smooth dissipation of a heat generated during operation of the motor 4 to keep accumulation of the heat inside of the motor 4, that causes thermal distortion of the lower frame 21 and various components, and degrades the performance rapidly and shortens a lifetime of the motor. Moreover, the many steps required for injection molding of the rotor 20 in fabrication of the brushless motor 4 takes much time period, which drops a productivity, and the reinforcement required for the rotor 20 increases a total weight.
Second, the requirement for a separate device, such as a jig(not shown), for fitting the magnets 22 to the related art lower frame 21 at fixed intervals leads to a complicated fabrication process. That is, the fastening of the magnets 22 to the jig and winding the back yoke 23 therearound for fitting the magnets 22 to the lower frame 21 requires many fabrication steps, that causes many defects, to increase a production cost.
Accordingly, the present invention is directed to a brushless motor in a 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 in a washing machine, which can prevent an internal heating, for making a stable operation.
Another object of the present invention is to provide a brushless motor in a washing machine, which can simplify the steps of process for fitting the magnets to a rotor.
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 hereof 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, the brushless motor in a washing machine including a stator havihg a coil coupled to an upper frame, and a rotor having a lower frame entirely formed of a metal to cover an outer circumference and a bottom of the stator, a plurality of magnets fitted to an inside wall of the lower frame at fixed intervals opposite to the coil of the stator, and a support member formed as one unit with, and at a central portion of the lower frame coupled to a washing water shaft for transmission of a rotating force of the lower frame to the washing water shaft.
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:
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Though the lower frame 210 of the rotor 200 of steel plate in the first embodiment of the present invention permits, not only smooth heat dissipation of the heat from the motor 4, but also easy fitting of the magnets 220 on the lower frame 210, a property of the material causes a problem of short circuit. That is, once an insulation between the coil 120 of the stator 100 and the lower frame 210 of the rotor 200 are broken, a current flowed to the coil 120 flows to the lower frame 210, and, therefrom to the shaft 5 through the support member 300, and, eventually, to the inner tub 1 and the washing water in the outer tub 2, that may causes an accident. This is caused since the lower frame 210 and the support member 300 are formed of a conductive material as one unit. In a case the lower frame 210 and the support member 300 are formed of the same materials, a vibration caused by rotation of the rotor 200 is transmitted to the support frame 300 through the lower frame 210, and therefrom to the shaft 5. That is, since the materials are the same, the natural frequencies are the same, which allows direct transmission of the vibration occurred by the rotation of the lower frame 210 without attenuation, that results in complain from users as the vibration deteriorates a product reliability.
Accordingly, the second embodiment of the present invention suggests to provide a support member 300 formed of an insulating material different from a material of the lower frame 210. That is, the support member 300 of the insulating material can prevent flow of the current flowed along the lower frame 210 to the shaft 5 through the support member 300, even if the insulation between the coil 120 of the stator 100 and the lower frame 210 of the rotor 200 is broken. Furthermore, the formation of the lower frame 210 and the shaft 300 of different materials differ natural frequencies, to attenuate a portion of the vibration transmitted through the lower frame 210 by the shaft 300. It can be known that the attenuation of the vibration to the shaft 5 permits a low noise operation of the washing machine. On the other hand, the formation of the support member 300 of the insulating material causes to require additional reinforcement of the support member 300. Accordingly, as shown in
In the meantime, the formation of the lower frame 210 and the support member 300 of different materials may cause the fabrication process to form as one unit to require more steps. To cope with this, a third embodiment of the present invention suggests to form a support member 300 which can be coupled to the lower frame selectably, according to the following various methods. That is, as shown in
However, the present invention suggests a system as illustrated in
The brushless motor in a washing machine of the present invention has the following advantages as a material of the brushless motor is improved and various deficiencies resulted in following the change of material are supplemented.
Smooth hedt dissipation from the motor can be achieved, to prevent deterioration of a motor performance coming from the heat of the motor performance.
Smooth drainage of the washing water accumulated in the brushless motor can be achieved, to permit to prevent short circuit between the coil in the stator and the shaft in advance.
The easy and stable fitting of the magnets to the inside surface of the lower frame in the rotor shortens an overall fabrication process and time period.
It will be apparent to those skilled in the art that various modifications and variations can be made in the brushless motor in a washing machine of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8621896 *||Nov 29, 2006||Jan 7, 2014||Lg Electronics Inc.||Washing machine|
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|U.S. Classification||310/261.1, 310/52, 310/156.26, 403/361, 310/67.00R, 68/140, 68/12.24, 310/266|
|International Classification||D06F37/40, H02K1/28, H02K1/27, D06F37/30, H02K1/30, H02K29/00, H02K7/14, H02K21/22|
|Cooperative Classification||H02K1/30, H02K1/2786, H02K2205/09, H02K7/14, H02K9/06, D06F37/304, Y10T403/7039|
|European Classification||D06F37/30C, H02K1/27C, H02K1/30, H02K9/06|