Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-40872, filed on Feb. 17, 2005, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a drum type washing machine comprising a water tub and a drum mounted in the water tub for carrying out wash and dehydration operations.  
         [0004]     2. Description of the Related Art  
         [0005]     Conventional drum type washing machines include a water tub and a cylindrical drum mounted in the water tub. The drum is rotated about an axis so that laundry put therein is agitated in a wash step. Furthermore, the drum is rotated at higher speeds or spun so that laundry is dehydrated by centrifugal force.  
         [0006]      FIG. 13  illustrates one of the conventional drum type washing machines of the above-described type.  FIG. 13  shows an end plate  101   a  of a drum  101  as viewed at outside. A drum support  102  die-cast from aluminum is mounted on the end plate  101   a.  A shaft  103  is connected with a central part of the drum support  102  for rotating and supporting the drum  101 . Reinforcement ribs (rugged contour)  102   a  are formed on an outer surface of the drum support  102 .  
         [0007]     JP-A-11-207077 discloses a drum type washing machine in which a drum support is provided on an end plate of a drum.  
         [0008]     In the above-described conventional construction, stepped portions are formed on the end plate  101   a  of the drum  101  since the drum support  102  is mounted on the end plate  101   a.  Furthermore, since the ribs  102   a  are formed on the drum support  102 , the ribs and the stepped portions are resistive against rotation of the drum when the drum  101  is rotated at high speeds or spun. As a result, the ribs and the stepped portions cause wind, producing loud noise. Additionally, power consumption is large since the ribs and the stepped portions are resistive against rotation of the drum.  
       SUMMARY OF THE INVENTION  
       [0009]     Therefore, an object of the present invention is to provide a drum type washing machine in which reduction in noise and power consumption can be achieved by decreasing an amount of resistance against rotation of the drum.  
         [0010]     The present invention provides a drum type washing machine including a water tub, a drum mounted in the water tub so as to be rotatable a wash operation and a dehydration operation are carried out, the drum including an end plate, a drum support provided on the end plate of the drum and including a mount portion on which a shaft supporting the drum is mounted thereon, and a cover covering the mount portion of the drum support so that the mount portion is rendered substantially planar.  
         [0011]     The invention also provides another drum type washing machine comprising a water tub, a drum mounted in the water tub so as to be rotatable so that a wash operation and a dehydration operation are carried out, the drum including an end plate having a recess with a bottom, and a drum support enclosed in the recess of the end plate of the drum and including a mount portion on which a shaft supporting the drum is mounted thereon, wherein the drum support has a first side facing the bottom of the recess and provided with a reinforcing corrugated portion, and wherein the drum support has a second side opposed to the first side and substantially planar. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Other objects, features and advantages of the present invention will become clear upon reviewing the following description of the embodiment with reference to the accompanying drawings, in which:  
         [0013]      FIG. 1  is a perspective view of a drum type washer-drier in accordance with one form of the disclosure;  
         [0014]      FIG. 2  is a longitudinal section of the drum type washer-drier;  
         [0015]      FIG. 3  is a perspective view of a drum with a flow regulator cover being detached;  
         [0016]      FIG. 4  is a perspective view of the drum with the flow regulator cover being attached;  
         [0017]      FIGS. 5A and 5B  are graphs showing results of noise measurement executed before and after attachment of the flow regulator cover respectively;  
         [0018]      FIG. 6  is a view similar to  FIG. 4 , showing the drum employed in the drum type washer-drier in accordance with a second form of the disclosure;  
         [0019]      FIG. 7  is a view similar to  FIG. 4 , showing the drum employed in the drum type washer-drier in accordance with a third form of the disclosure;  
         [0020]      FIG. 8  is a view taken along line  8 - 8  in  FIG. 7 ;  
         [0021]      FIG. 9  is a view similar to  FIG. 2 ;  
         [0022]      FIG. 10  is a view similar to  FIG. 4 , showing a modified form;  
         [0023]      FIG. 11  is a view taken along line  11 - 11  in  FIG. 10 ;  
         [0024]      FIG. 12  is a view similar to  FIG. 7 , showing another modified form;  
         [0025]      FIG. 13  is a rear view of a conventional drum type washing machine. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]     Several embodiments of the present invention will be described. FIGS.  1  to  5 B illustrate a first embodiment in accordance with the invention. Referring to  FIG. 1 , an overall construction of a drum type washer-drier of the first embodiment is shown. The drum type washer-drier includes a base  1  made of a resin. A generally rectangular outer cabinet  2  is mounted on the base  1 . The cabinet  2  includes a front cover  3  having a centrally formed access opening  3   a  (see  FIG. 2 ) through which laundry is put into and taken out of a drum. A door  4  is mounted on the front cover  3  so as to open and close the opening  3   a.    
         [0027]     An operation panel  5  is mounted on the front cover  3  so as to be located above the door  4 . The operation panel  5  is provided with various switches for selecting or setting an operation course or the like. A wash operation, a dehydration operation or a wash-dehydration operation in which the wash and dehydration operations are continuously carried out can be selected on the operation panel.  
         [0028]     Referring now to  FIG. 2 , a cylindrical water tub  6  is supported by suspension mechanisms  7  (only one shown) which are further mounted on the base  1 . Each suspension mechanism  7  includes a coil spring and a damper. Thus, the water tub  6  is mounted on the base  1  in the cabinet  2 . A drum  8  made of stainless steel (SUS403, for example) is mounted in the water tub  6 . The water tub  6  and the drum  8  serve as a wash tub in combination. Each of the water tub  6  and the drum  8  is disposed so that a central axis thereof is inclined rearwardly downward.  
         [0029]     A brushless DC motor  9  of the outer rotor type is fixed to a rear end of the water tub  6 . The motor  9  includes a shaft  10  which extends through an end face of the water tub  6  into an interior of the water tub  6 . The shaft  10  has a distal end connected to a drum support  11  mounted on an end plate  8   b  of the drum  8 . Upon rotation of a rotor of the motor  9 , the shaft  10  is rotated together with the rotor, whereby the drum  8  is rotated.  
         [0030]     The drum  8  includes a peripheral wall and the end plate  8   b  both formed with a number of holes  12  serving both as air vents and as water vents. Some of the holes  12  are shown in  FIG. 2 . Furthermore, a drain hole (not shown) is formed through the lower rear (lowermost portion) of the water tub  6 . A drain pipe  13  is connected to the drain hole. A lower end of the drain pipe  13  is connected via a drain valve  14  to another drain pipe  15 . The water tub  6  and drum  8  have front ends formed with openings  6   a  and  8   a  respectively. The openings  6   a  and  8   a  communicate via bellows  16  with the opening  3   a  of the front cover  3 .  
         [0031]     A ventilation duct  17  is provided over the top of the water tub  6  so as to face the interior of the water tub. The ventilation duct  17  is provided with a heater  18 . A blowing fan  19  is provided at an upstream side with respect to the ventilation duct  17 . The blowing fan  19  supplies air flow into the water tub  6 . A further upstream side of the ventilation duct  17  is connected to the water tub  6  so as to face the interior of the water tub. Furthermore, a heat pump including a condenser and an evaporator is also provided though not shown. Accordingly, upon operation of the heater  18  and blowing fan  19 , air in the water tub  6  and drum  8  is adapted to be circulated and dehumidified upon operation of the heater  18  and blowing fan  19 . Additionally, a control device  20  is provided inside the operation panel in the interior of the cabinet  2 . The control device  20  controls an overall operation of the washer-drier.  
         [0032]     A user operates switches on the operation panel  5  so that an operation course is set in the washer-drier constructed as described above. When start of operation is instructed, a washing operation or a drying operation is carried out according to a set operation course or a washing-drying operation is carried out so that washing and drying operations are continuously carried out. For example, when the washing-drying operation has been started, a wash step, a dehydration step and a drying step are sequentially carried out.  
         [0033]     A concrete construction of the mounting portion of the drum support  11  on the drum  8  will now be described with reference to  FIGS. 3 and 4 .  FIG. 3  shows the drum support  11  mounted on the drum  8 . The drum support  11  includes a central portion  11   a  and three protrusions  11   b  extending radially from the central portion  11   a  at regular intervals. The drum support  11  is die-cast from aluminum. The drum support  11  has an outer surface or a side opposite the end plate  8   b  of the drum  8 . A number of ribs  11   c  protrude from the outer surface of the drum support  11  configured as shown in  FIG. 3 . The ribs  11   c  constitute a reinforcing corrugated portion of the drum support  11 .  
         [0034]     The end plate  8   b  of the drum  8  has a recess  8   c  in which the drum support  11  is to be accommodated. The recess  8   c  is formed so as to be swollen inside the drum  8 . In this case, the drum support  11  is accommodated in the recess  8   c  and thereafter, distal ends of the respective protrusions  11   b  of the drum support  11  are screwed onto the peripheral wall of the drum  8 . Furthermore, the drum support  11  is fixed to the drum  8  by scrimping.  
         [0035]     Referring now to  FIG. 4 , a rectifying cover  21  is mounted on the end plate  8   b  of the drum  8  so as to close the recess  8   c  and so as to cover the drum support  11 . The rectifying cover  21  is made of stainless steel (SUS403) which is the same material as the drum  8 . The rectifying cover  21  is formed so as to be larger than the recess  8   c . The rectifying cover  21  has a centrally located through hole  21   a  through which the shaft  10  and the like are to be inserted (see  FIG. 3 ).  
         [0036]     The end plate  8   b  of the drum  8  and the rectifying cover  21  are adapted to be substantially co-planar when the rectifying cover  21  is mounted on the end plate  8   b . The rectifying cover  21  is screwed on the end plate  8   b  by making using of some of the holes  12  formed through the end plate.  
         [0037]     The drum support  11  is accommodated in the recess  8   c  of the drum  8  to be fixed therein. The recess  8   c  is then mounted on the end plate  8   b  so as to close the recess  8   c  and cover the drum support  11 . As a result, since an outer surface of the end plate  8   b  is substantially flat, rotational resistance and accordingly noise can be reduced when the drum  8  is rotated at high speeds (1400 rpm, for example) in the dehydration step. Furthermore, power consumption of the washer-drier can also be reduced as the result of reduction in the rotational resistance.  
         [0038]      FIGS. 5A and 5B  show the results of measurement of noise regarding the washer-drier of the embodiment. More specifically,  FIGS. 5A and 5B  show the results of fast Fourier transform (FFT) analysis carried out with respect to noise produced from dehydration operation of the drum type washer-drier of the embodiment.  FIG. 5A  shows the results of measurement with respect to the construction before attachment of the rectifying cover  21 , whereas  FIG. 5B  shows the results of measurement with respect to the construction after attachment of the rectifying cover  21 . The axis of abscissas represents frequency in Hz and the axis of ordinates represents sound pressure level in dB in  FIGS. 5A and 5B .  
         [0039]     In comparison of  FIGS. 5A and 5B , it can be considered that the sound pressure level is sufficiently reduced in a frequency band ranging from about 2 kHz to about 5 kHz when the rectifying cover  21  is attached to the drum  8 . It is noted that the aforesaid frequency band corresponds to the noise produced by the frequency band (the frequency band of not more than about 2 kHz corresponds to noise produced by the motor).  
         [0040]     Furthermore, since the rectifying cover  21  and the drum  8  are made of the same material, that is, stainless steel (SUS403), crevice corrosion can be restrained in the washer-drier of the embodiment as compared with the construction in which the rectifying cover and the drum are made of different materials. Additionally, the drum support  11  includes the central portion  11   a  and the three protrusions  11   b  extending radially from the central portion  11   a  at regular intervals. Since the rectifying cover is formed so as to correspond to the shape of the drum support  11 , an amount of material for the rectifying cover  21  can be reduced in the embodiment as compared with the case where an entire end plate  8   b  is covered with a rectifying cover.  
         [0041]      FIG. 6  illustrates a second embodiment of the invention. In the second embodiment, similar or identical parts are labeled by the same reference symbols as those in the first embodiment. As shown in  FIG. 6 , the rectifying cover  22  in the second embodiment is sized so that portions of the outer periphery of the recess  8  are exposed. More specifically, the rectifying cover  22  is formed so that a radial dimension thereof is slightly shorter that that of the end plate  8   b . When the rectifying cover  22  is mounted on the end plate  8   b , gaps  8   e  are defined between the outer periphery of the recess  8   c  and the rectifying cover  22 . The other construction of the washer-drier of the second embodiment is substantially the same as in the first embodiment.  
         [0042]     According to the second embodiment, the gaps  8   e  located at the outer peripheral side of the end plate  8   b  serve as drain holes. Consequently, water remaining between the recess  8   c  and the rectifying cover  22  can reliably be discharged.  
         [0043]     FIGS.  7  to  9  illustrate a third embodiment of the invention. In the third embodiment, similar or identical parts are labeled by the same reference symbols as those in the first embodiment. Referring to  FIG. 8 , the drum support  23  has an inner surface facing the bottom of the recess  8   c . The inner surface of the drum support  23  is formed with reinforcing ribs (a reinforcing corrugated portion). The drum support  23  further has an outer surface which is a side opposite the side thereof facing the bottom of the recess  8   c . The outer surface of the drum support is substantially planar.  
         [0044]     The drum support  23  has a flange  23   b  (see  FIG. 8 ) formed on the outer periphery thereof so as to close the opening of the recess  8   c . The protrusions  23   b  of the drum support  23  have respective distal ends (or portions located at the outer peripheral side of the drum  8 ) formed with holes  23   c.    
         [0045]     In the above-described construction, the drum support  23  is mounted on the drum  8  so that the ribs  23   a  face the end plate  8   b  side (the bottom of the recess  8   c ) as shown in  FIG. 9 . As a result, the opening of the recess  8   c  is closed by the drum support  23  and the flange  23   b  of the drum support  23 . The other construction of the washer-drier of the second embodiment is substantially the same as in the first embodiment.  
         [0046]     In the third embodiment, the drum support  23  is disposed in the recess  8   c  of the drum  8  so that the reinforcing ribs  23   a  of the drum support are face the end plate  8   b  side and so that the end plate  8   b  and the drum support  23  are substantially co-planar. Accordingly, rotational resistance can be reduced when the drum  8  is rotated at high speeds in the dehydration step, whereupon noise can be reduced. Since the rectifying cover  21  employed in the first embodiment is eliminated particularly in the third embodiment, the number of components can be reduced and accordingly, a cost reduction can be achieved.  
         [0047]     Furthermore, further noise reduction and further power consumption can be achieved since the flange  23   b  is provided on the drum support  23  so as to close the opening of the recess  8   c.    
         [0048]     The flange  23   b  may or may not be provided although the drum support  23  is provided with the flange  23   b  in the third embodiment.  
         [0049]     The invention should not be limited to the embodiments described above with reference to the accompanying drawings. The embodiments may be modified or expanded as follows. In the first embodiment, the recess  8   c  is formed in the end plate  8   b  of the drum  8 . The drum support  11  is accommodated in the recess  8   c . The drum support  11  is then mounted on the drum  8 . However, the drum support  11  may be mounted on the drum  8  without provision of the recess  8   c  in the end plate  8   b . In this case, a rectifying cover may be mounted on the drum  8  and preferably has such a circular plate shape as to cover the entire end plate  8   b  or has substantially the same size as the end plate  8   b.    
         [0050]     Furthermore, as shown in  FIGS. 10 and 11 , the recess  8   c  of the drum  8  has an opening edge formed with a stepped portion  8   d  which has substantially the same thickness as the rectifying cover  21 . The rectifying cover  21  may be fitted with the stepped portion  8   d.  In this case, the rectifying cover  21  is preferably recessed slightly relative to the face of the end plate  8   b . As the result of the aforesaid construction, the difference corresponding to the thickness of the rectifying cover  21  is resolved and the rectifying cover  21  is slightly recessed. Consequently, since resistance of wind against the end face of the rectifying cover  21  can further be reduced during high speed rotation of the drum  8 , noise can further be reduced and power consumption can further be reduced. Additionally, a packing may be provided on the end face on which the stepped portion  8   d  is in contact with the rectifying cover  21 .  
         [0051]     Furthermore, the gaps  8   e  are defined between the outer periphery of the recess  8   c  and the rectifying cover  22 . However, as shown in  FIG. 12 , drain holes  21   b  may be formed in distal ends of the protrusions  21   b  (near the outer periphery of the drum  8 ). Each drain hole  21   b  may take any shape even if water is allowed to pass therethrough. For example, each drain hole  21   b  may be a notch.  
         [0052]     The invention is applied to the drum washer-dryer of the front loading type in each of the foregoing embodiments. However, the invention may be applied to a drum washer-drier of the top loading type.  
         [0053]     The foregoing description and drawings are merely illustrative of the principles of the present invention and are not to be construed in a limiting sense. Various changes and modifications will become apparent to those of ordinary skill in the art. All such changes and modifications are seen to fall within the scope of the invention as defined by the appended claims.

Technology Category: 6