Patent Publication Number: US-8991222-B2

Title: Washing machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/379,607, filed on Feb. 25, 2009, which is currently pending, and claims the priority benefit of Korean Utility Model Application No. 20-2008-2833, filed on Mar. 4, 2008, and Korean Patent Application No. 10-2009-0000708, filed on Jan. 6, 2009 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments relate to a washing machine, and, more particularly, to a washing machine of an improved structure to prevent the generation of noise and vibration between a rotary shaft and a bearing. 
     2. Description of the Related Art 
     Generally, a washing machine is classified as a pulsator type washing machine that washes laundry by rotating wash water and the laundry using a pulsator rotatably installed on the bottom of the inside of a water tub, an agitator type washing machine that washes laundry by agitating wash water and the laundry using an agitator protruding from the central region of the inside of a water tub, or a drum type washing machine that washes laundry by repeatedly lifting and dropping the laundry through the rotation of a drum accommodating the laundry. 
     An example of such a drum type washing machine is disclosed in U.S. Pat. No. 6,510,716 providing a drum type washing machine including a water tub, a rotary tub rotatably disposed in the water tub, the rotary tub having a rotary shaft extending to the outside of the water tub, a bearing to rotatably retain the rotary shaft, and a drive motor connected to the rotary shaft at the outside of the water tub to simultaneously rotate the rotary shaft and the rotary tub. 
     The disclosed drum type washing machine is capable of performing a spin-drying function as well as a washing function. During spin-drying, the rotary shaft and an inner race of the bearing to retain the rotary shaft rotate at high speed, with the result that the rotary shaft and the bearing cannot rotate at the same speed. That is, there is difference in rotation speed between the rotary shaft and the bearing. 
     At this time, the inner race of the bearing and the outer diameter of the rotary shaft repeatedly come into contact with each other and separate from each other due to the difference in rotation speed between the rotary shaft and the bearing, with the result that there occurs a sliding phenomenon between the bearing and the rotary shaft, which generates creep noise. 
     Also, between an inner race of a bearing installed at the front side of the rotary shaft and a front-side step of the rotary shaft is formed a gap which causes noise and vibration. 
     To solve this problem, a wave washer has been used. 
     However, the wave washer is installed only between the inner race of the bearing installed at the front side of the rotary shaft and the front-side step of the rotary shaft, with the result that the sliding between the bearing and the rotary shaft is not fundamentally restrained, and therefore, a noise and vibration reduction effect is insignificant. In addition, a compression force is continuously applied between the inner race of the bearing and the front-side step, with the result that the wave washer is permanently deformed, and therefore, noise and vibration increase with the increase of the use time of the washing machine. Also, a frictional force providing effect, to provide a frictional force between the rotary shaft and the inner race of the bearing such that the rotary shaft and the bearing can rotate at the same speed, is insignificant. This is because, due to the shape (wave-shaped ring) of the wave washer, the frictional force is generated only at some region where the front-side step of the rotary shaft and the front side of the inner race of the bearing come into contact with the wave shape of the wave washer. 
     SUMMARY 
     It is an aspect of embodiments to provide a washing machine that is capable of restraining sliding between a rotary shaft and a bearing and uniformly maintaining a gap between the rotary shaft and the bearing, thereby preventing creep noise and vibration. 
     In accordance with one aspect of embodiments, there is provided a washing machine including a rotary shaft and a bearing to rotatably retain the rotary shaft, wherein the washing machine further includes at least one elastic member disposed between an outer diameter of the rotary shaft and an inner race of the bearing to prevent noise due to a sliding between the rotary shaft and the bearing. 
     The at least one elastic member may include an O-ring. 
     The at least one elastic member may include an annular leaf spring. 
     The at least one elastic member may include an O-ring and an annular leaf spring. 
     In accordance with another aspect of embodiments, there is provided a washing machine including a rotary shaft, a bearing to rotatably retain the rotary shaft, an O-ring disposed between the rotary shaft and the bearing, and an annular leaf spring mounted to wrap an outside of the O-ring, the annular leaf spring having a diameter gradually decreasing from one side to the other side. 
     In accordance with another aspect of embodiments, there is provided a washing machine including a rotary shaft and a bearing to rotatably retain the rotary shaft, wherein the washing machine further includes at least one circular elastic member to separate a front-side step of the rotary shaft and an inner race of the bearing from each other and separate the rotary shaft and the inner race of the bearing from each other to prevent the interference between the rotary shaft and the inner race of the bearing. 
     The at least one circular elastic member may include an O-ring. 
     The at least one circular elastic member may include an annular leaf spring having a diameter gradually decreasing from one side to the other side. 
     The at least one circular elastic member may include an O-ring and an annular leaf spring. 
     The O-ring may be made of a rubber material. 
     The annular leaf spring may be made of an iron material. 
     In accordance with a further aspect of embodiments, there is provided a structure to prevent gap noise at a rotary shaft of a washing machine, including a rotary shaft, a bearing to rotatably retain the rotary shaft, and at least one circular elastic member disposed between a front-side step of the rotary shaft and a front-side bent portion of an inner race of the bearing. 
     The at least one circular elastic member may include an O-ring. 
     The at least one circular elastic member may include an annular leaf spring having a diameter gradually decreasing from one side to the other side. 
     The at least one circular elastic member may include an O-ring and an annular leaf spring. 
     The O-ring may be made of a rubber material. 
     The annular leaf spring may be made of an iron material. 
     In accordance with a further aspect of embodiments, there is provided a structure in a washing machine to prevent gap noise at a rotary shaft which is rotatably retained by a bearing, the structure comprising at least one circular elastic member disposed between a front-side step of the rotary shaft and a front-side bent portion of an inner race of the bearing. 
     Additional aspects and/or advantages of embodiments will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, of which: 
         FIG. 1  is a sectional view schematically illustrating a drum type washing machine according to an exemplary embodiment; 
         FIG. 2  is a view illustrating the assembly of a rotary shaft and a bearing of  FIG. 1 ; 
         FIG. 3  is a sectional view illustrating an O-ring, mounted between the rotary shaft and the bearing, according to an exemplary embodiment; 
         FIG. 4  is a sectional view illustrating an annular leaf spring, mounted between the rotary shaft and the bearing, according to another exemplary embodiment; and 
         FIG. 5  is a sectional view illustrating an O-ring and a leaf spring, mounted between the rotary shaft and the bearing, according to a further exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. Exemplary embodiments are described below by referring to the figures. 
     As shown in  FIG. 1 , the washing machine includes a machine body  10  forming the appearance of the washing machine, a water tub  14  installed in the machine body  10  to receive wash water, a rotary tub  12  rotatably installed in the water tub  14  to wash laundry, and a door  11  installed at the front of the machine body  10  to open and close the front of the machine body  10 . 
     At the upper inside of the machine body  10  are mounted a water supply pipe  13  to supply wash water and a detergent to the water tub  14  and a detergent supply unit  17 . At the lower inside of the machine body  10  are mounted a drainage pipe  15  and a drainage pump  16  to drain wash water from the water tub  14  to the outside. 
     At the outside rear of the water tub  14  is mounted a drive motor  20  to rotate the rotary tub  12  in alternating directions. Between the rotary tub  12  and the drive motor  20  is mounted a rotary shaft  30  to transmit a drive force from the drive motor  20  to the rotary tub  12 . 
     The rotary shaft  20  has one end connected to the rotary tub  12  and the other end coupled to a back  14   a  of the water tub  14  such that the other end is connected to the drive motor  20 . 
     At the back  14   a  of the water tub  14  is mounted a bearing housing  40  to extend the rotary shaft  30  such that the rotary shaft  30  can rotate outside the water tub  14 . The drive motor  20  is coupled to the back  14   a  of the water tub via the bearing housing  40 . 
     Also, bearings  41  to rotatably retain the rotary shaft  30  are installed in the bearing housing  40  at the front and rear sides of the rotary shaft  30 , respectively. 
     As shown in  FIGS. 2 to 5 , a gap is formed between the rotary shaft  30  and a bearing  41  to rotatably retain the rotary shaft  30 . 
     That is, an outer diameter d 1  of the rotary shaft  30  is not equal to an inner race d 2  of the bearing  41 . Consequently, a gap is formed between the inner race d 2  of the bearing  41  and the outer diameter d 1  of the rotary shaft  30 . Due to the gap, there occurs a sliding phenomenon between the rotary shaft  30  and the bearing  41 . 
     Also, between a front-side step  35  of the rotary shaft  30  and the front side of the inner race d 2  of the bearing  41  is formed a gap, which causes noise and vibration. 
     In the washing machine, a circular elastic member  50  exhibiting elasticity is disposed between the outer diameter d 1  of the rotary shaft  30  and the inner race d 2  of the bearing  41 , more exactly between the front-side step  35  of the rotary shaft  30  and a front-side bent portion  45  of the inner race d 2  of the bearing  41 . The circular elastic member  50  uniformly maintains the gap between the rotary shaft  30  and the bearing  41  and increases a frictional force between the rotary shaft  30  and the inner race d 2  of the bearing  41 . Consequently, the gap between the rotary shaft  30  and the bearing  41  is uniformly maintained by the circular elastic member  50 , and the rotation speed of the rotary shaft  30  remains equal to that of the bearing  41 , whereby the sliding between the rotary shaft  30  and the bearing  41  is prevented. 
     Therefore, it is possible to prevent the generation of creep noise due to the sliding between the rotary shaft  30  and the bearing  41 . 
     The circular elastic member  50  is formed in a circular shape and made of an elastic material. The circular elastic member  50  is disposed between the outer diameter d 1  of the rotary shaft  30  and the inner race d 2  of the bearing  41 , more exactly between the front-side step  35  of the rotary shaft  30  and the front-side bent portion  45  of the inner race d 2  of the bearing  41 . 
       FIG. 3  illustrates the circular elastic member  50  implemented by an O-ring  51 , which is a ring having a circular section. The O-ring  51  may be made of a rubber material. 
     By fitting the O-ring  51  on the outer diameter of the rotary shaft  30  and coupling the bearing  41 , it is possible to restrain the sliding between the rotary shaft  30  and the bearing  41  such that the rotary shaft  30  and the bearing  41  can rotate at a uniform speed. 
     Also, it is possible for the rotary shaft  30  and the bearing  41  to rotate at the same speed by the O-ring  51  disposed between the rotary shaft  30  and the bearing  41  even when the rotary shaft  30  and the bearing  41  rotate at high speed during spin-drying. Consequently, the sliding between the rotary shaft  30  and the bearing  41  is prevented, thereby restraining creep noise. 
       FIG. 4  illustrates another embodiment. Specifically, the circular elastic member  50  is implemented by an annular leaf spring  52 . The diameter of one side of the leaf spring  52  is less than that of the other side of the leaf spring  52 , and therefore, the leaf spring  52  has an incline. The leaf spring  52  may be of an iron material. 
     The leaf spring  52  is fitted on the outer surface of the rotary shaft  30 , and the bearing  41  is assembled such that the bearing  41  is in contact with the outer incline of the leaf spring  52  fitted on the rotary shaft  30 . 
     That is, the leaf spring  52  is disposed in the gap between the outer diameter d 1  of the rotary shaft  30  and the inner race d 2  of the bearing  41  to restrain the sliding between the rotary shaft  30  and the bearing  41 . 
     Also, the rotary shaft  30  and the bearing  41  rotate at the same speed even when the rotary shaft  30  and the bearing  41  rotate at high speed, and there is no interference between the rotary shaft  30  and the bearing  41 , thereby preventing the generation of creep noise between the rotary shaft  30  and the bearing  41 . 
       FIG. 5  illustrates a further embodiment. Specifically, the circular elastic member  50  is implemented by a combination of the O-ring  51  and the annular leaf spring  52 . 
     The O-ring  51  is fitted outside the rotary shaft  30  and the annular leaf spring  52  is coupled to the outside of the O-ring  51 . 
     The O-ring  51  is in contact with the inner lower part of the leaf spring  52  to constrain the sliding between the rotary shaft  30  and the bearing  41 , thereby preventing the generation of creep noise between the rotary shaft  30  and the bearing  41 . 
     Table 1.1 shows measured values of noise and out-of-phase frequencies when using the O-ring  51  and the annular leaf spring  52 . 
     
       
         
           
               
               
               
             
               
                 TABLE 1.1 
               
               
                   
               
               
                   
                   
                 Out-of-phase frequency 
               
               
                 Classification 
                 Noise (dBA) 
                 (Hz) 
               
               
                   
               
             
            
               
                 Wave washer (Conventional) 
                 57.6 
                 41.8 
               
               
                 O-ring 
                 58.4 
                 — 
               
               
                 Leaf spring 
                 56.6 
                 41.5 
               
               
                 O-ring and Leaf spring 
                 54.4 
                 44.6 
               
               
                   
               
            
           
         
       
     
     As can be seen from Table 1.1, the noise was lower by 3.6 dBA when using the O-ring  51  and the annular leaf spring  52  than when using the conventional wave washer. Considering that the unit dBA is a log scale, the noise reduction effect is considerably remarkable. The out-of-phase frequency also increased. 
     Hereinafter, a process to constrain creep noise during spin-drying according to the finally mentioned embodiment will be described. 
     When a user operates the washing machine in a spin-drying mode, the drive motor  20  is operated to rotate the rotary shaft and the rotary tub  12 , connected to the rotary shaft  30 , at high speed to perform a spin-drying process. At this time, the inner race d 2  of the bearing  41  rotates at the same speed as the rotary shaft  30  by the O-ring  51  and the annular leaf spring  52  disposed between the front-side step  35  of the rotary shaft  30  and the front-side bent portion  45  of the inner race d 2  of the bearing  41 , whereby the generation of creep noise is constrained. This is because the O-ring  51  and the annular leaf spring  52  uniformly maintain the gap between the rotary shaft  30  and the inner race d 2  of the bearing  41  and provide a great frictional force to constrain the sliding between the rotary shaft  30  and the bearing  41 . 
     As apparent from the above description, the O-ring and the leaf spring are disposed between the outer diameter of the rotary shaft and the inner race of the bearing in the washing machine to constrain the sliding between the rotary shaft and the bearing. Consequently, the embodiments have the effect of preventing creep noise and vibration. 
     Also, the smooth rotation of the rotary shaft and the bearing is achieved. Consequently, embodiments have the effect of improving the durability and life span of the bearing. 
     Also, the O-ring and the leaf spring are not deformed even after the long-term use of the washing machine. Consequently, embodiments have the effect of preventing the increase of noise and vibration. 
     Although a few exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in exemplary embodiments without departing from the principles and spirit of embodiments, the scope of which is defined in the claims and their equivalents.