Patent Publication Number: US-9404209-B2

Title: Laundry machine

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a U.S. National Stage Application under 35 U.S.C. §371 of PCT Application No. PCT/KR2010/003382, filed May 27, 2010, which claims priority to Korean Patent Application No. 10-2010-0046455, filed May 18, 2010, Korean Patent Application No. 10-2009-0079829, filed Aug. 27, 2009, Korean Patent Application No. 10-2009-0079950, filed Aug. 27, 2009, Korean Patent Application No. 10-2009-0079909, filed Aug. 27, 2009, and Korean Patent Application No. 10-2009-0047192, filed May 28, 2009. 
     TECHNICAL FIELD 
     The present invention relates to a laundry machine, more specifically, to a laundry machine which has an improved structure to improve washing efficiency. 
     BACKGROUND ART 
     Generally, laundry machines are electric appliances which remove various kinds of contaminants attached to clothes, beddings, cloth items and the like (hereinafter, laundry) by way of a friction force of water currents generated by rotation of a drum and a shock applied to laundry including clothes and the other items. A full-automatic laundry machine released in recent has a series of cycles including a washing, rinsing, dry-spinning cycle which are implemented automatically. 
     Instead of pulsator type laundry machine having a tub rotatable in a state of standing vertically, drum type laundry machines having little problems of entangled laundry and a lot of wrinkles generated in the laundry have been more and more popular recently. 
     As a structure of such a drum type laundry machine mentioned above is described schematically, the drum type laundry machine includes a cabinet configured to define an exterior appearance thereof, a tub located in the cabinet to receive wash water, with being supported by a damper an a spring, and a cylindrical drum located in the tub to receive laundry therein. The drum receives a driving force from a driving part to implement washing for the laundry loaded into the drum. 
     According to the structure of the drum type laundry machine mentioned above, the drum is rotated to wash and dry-spin the laundry loaded therein and it is vibrated because of the rotational force of the drum and eccentricity of the laundry. The vibration generated by the rotation of the drum may be transmitted outside via the tub and the cabinet. 
     Because of that, a spring and a damper are provided essentially between the tub and the cabinet to prevent the vibration transmitted to the tub from transmitted to the cabinet. 
     The drum type laundry machine mentioned above may be installed in an existing installation circumstance, for example, in a sink or built-in circumstance, not installed separately. As a result, the size of the drum type laundry machine may be installed limited to be adjustable to its installation circumstance. 
     As mentioned above, it is limited for the structure of the spring and damper dampening the vibration of the tub and the cabinet to change an inner structure of the drum type laundry. As the installation circumstance of the laundry machine is limited, it is limited to change the size of the laundry machine. 
     A lot of researches and developments have been in progress to improve washing capacities of laundry machines for user convenience and the increased washed laundry amount. However, it is difficult to enlarge the size of the tub in the conventional drum type laundry machine to increase the washing capacity, because of the limitation condition mentioned above. 
     As a result, laundry machines having various types of structures have been under development to improve the washing capacity as mentioned above. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     To solve the problems, an object of the present invention is to provide a drum type laundry machine having a new structure, different from the conventional laundry machine. 
     Solution to Problem 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a laundry machine includes a tub configured to receive wash water; a drum rotatably installed in the tub; a shaft connected with the drum; a bearing housing configured to support the shaft; a tub back coupled to inner and outer circumferences of a front surface of the bearing housing; a rear gasket connected between the tub back and the tub; and a suspension unit configured to support vibration of the drum suspendingly. 
     A through-hole may be formed in a center of the tub back to pass the shaft there through and a gentle curvature surface projected toward an inside of the tub may be formed in an outer circumference of the through-hole. 
     Coupling bosses coupled to the bearing housing may be formed in an outer circumference of the though-hole formed in a rear surface of the tub back. 
     Coupling holes in which the coupling bosses are inserted may be formed in the bearing housing. 
     First and second extending parts extended in a radial direction may be formed in the bearing housing and auxiliary coupling bosses coupled to the first and second extending parts of the bearing housing may be formed in an outer circumference of the rear surface of the tub back. 
     Auxiliary coupling holes in which the auxiliary coupling bosses are inserted may be formed in the first and second extending parts of the bearing housing, respectively. 
     Ribs configured to reinforce rigidity of the tub back may be formed in a rear surface of the tub back. 
     The ribs may include radial ribs formed in a center of the tub back in a radial direction and circular ribs alternatively provided with respect to the radial ribs. 
     An inserting rim part may be projected along an inner circumferential surface of the through-hole toward a front part of the tub back. 
     A bearing supporting part configured to support the shaft may be provided in the bearing housing and the inserting rim part may be inserted in an inner circumferential surface of the bearing supporting part. 
     A bearing supporting part configured to support the shaft and a middle rib extended from the bearing supporting part in a radial direction may be formed in the bearing housing. 
     The middle rib may be extended from the bearing supporting part in a circumferential direction and the middle rib may be projected forward and recessed backward alternatively. 
     A tub back coupling part to which the tub back is coupled may be formed in a projected portion of the middle rib in a forward direction of the bearing supporting part. 
     The tub back coupling part may be formed in a gentle curvature shape having a center projected toward the tub. 
     The tub back may be coupled to the tub back coupling part by a coupling material configured to pass through a rear recessed portion of the middle rib. 
     The height of the recessed portion may be larger than the height formed by the coupling material. 
     A stator coupling part to which the stator is coupled may be formed in a projected portion of the middle rib in a backward direction of the bearing supporting part. 
     The middle rib may form an installation distance between the tub back and the stator. 
     The tub may be supported by the suspension unit more rigidly than the drum is supported. The suspension unit may include a supporting bracket extended toward a front part of the suspension unit in parallel to the shaft and a cylinder damper configured to support the supporting bracket. The tub may further include an opening formed in a front part thereof to load laundry therein and a door configured to open and close the opening. 
     In the meanwhile, according to the laundry machine, the tub may be fixedly installed or supported by a flexible structure such as the suspension unit. Or the supporting of the tub may be in the middle of the suspension supporting and the fixed supporting. 
     That is, the tub may be supported flexibly by using the suspension unit which will be described in detail in the description of the invention, or it may be supported more rigidly than the flexible supporting. For example, the tub may be supported by the suspension unit or a rubber bushing which can give a predetermined flexible motion to the tub, less flexible than the support by way of the suspension unit. Or the tub may be fixedly installed. 
     Examples of tubs supported more rigidly than the supporting of the suspension unit will be followed. 
     First of all, a predetermined portion of the tub may be integrally formed with the cabinet. 
     Second, the tub may be connected and supported by a screw, rivet, rubber bushing and the like or fixedly welled, adhered or sealed. In this case, the rigidity of the suspension unit is stronger than the rigidity of these connecting materials with respect to a vertical direction which is a main vibration direction of the drum. 
     Such the tub may be enlarged in a possible limited installation space. That is, the tub may be enlarged to be adjacent to a wall or frame, which limits the horizontal size of the installation space, with respect to at least a right and left direction orthogonal to a shaft direction if the shaft is horizontally installed. Here, the tub may be integrally formed with a right or left wall of the cabinet. 
     The tub may be closer to the wall or frame than to the drum in the right and left direction. For example, the tub may be 1.5 times or less as distant from the wall or frame by as from the drum. In the state of the tub enlarged in the right and left direction, the drum may be also enlarged in the right and left direction. As the right and left direction distance is getting smaller between the tub and the drum, the drum may be enlarged in the right and left direction as much. The right and left direction vibration of the drum may be put into consideration to reduce the right and left direction distance between the tub and the drum. As the right and left direction vibration of the drum is getting smaller, the diameter of the drum may be enlarged more. As a result, the right and left direction rigidity of the suspension unit configured to suspend the vibration of the drum may be larger than the other direction rigidity. For example, the rigidity of the suspension unit with respect to right and left direction displacement may be the maximum with respect to the other direction rigidity. 
     Furthermore, the suspension unit may be directly connected with the bearing housing configured to support the shaft connected with the shaft, different from the suspension unit connected via the tub according to the conventional laundry machine. That is, the bearing housing may include a supporting part configured to support the shaft and an extending part extended from the supporting part. The suspension unit may be coupled to the supporting part or the extending part of the bearing housing. 
     At this time, the suspension unit may include a bracket extended with respect to the shaft direction and the bracket may be extended forward to the door. 
     The suspension unit may include at least two suspensions distant from each other in the shaft direction. 
     The suspension unit may include a plurality of suspensions installed below the shaft to standing-support a supporting object, for example, the drum. The suspension unit may include a plurality of suspensions installed beyond the shaft to hang the supporting object thereto. According to these cases, suspensions are provided only below or beyond the shaft. 
     The gravity center of the vibration system including the drum, shaft, bearing housing and motor may be located in at least predetermined portion adjacent to the motor with respect to a longitudinal shape of the drum. 
     At least one suspension may be in front or rear of the gravity center or suspensions may be installed in front and rear of the gravity center, respectively. 
     The tub may include an opening formed in a rear part thereof. A driving part including the shaft, bearing housing and motor may be connected with the tub via a flexible material. The flexible material seals the opening formed in the rear part of the tub to prevent wash water from flowing out of the tub via the opening and to enable the driving part to relative-move with respect to the tub. Such the flexible material may be any flexible material which can seal, for example, gasket material such as front gasket. In this case, the flexible material may be named as rear gasket corresponding to the front gasket. The connection of the rear gasket with the driving part may be implemented in a rotational constrained state with respect to the rotational direction of the shaft. According to an embodiment, the rear gasket may be directly connected with the shaft or it may be connected with the extending part of the bearing housing. 
     A predetermined portion of the driving part which is located in a front connection with the rear gasket only to be exposed to wash water may be made of anticorrosive material. For example, the portion may be coated or covered with an auxiliary plastic-made part, for example, a tub back which will be described in detail. If there is a metal-made portion of the driving part, the metal-made portion may not be exposed to water directly and corrosion may be prevented accordingly. 
     Here, the cabinet may not be provided, different from the embodiment of the present invention. For example, a built-in laundry machine may be provided in a wall, instead of the cabinet. That is, the laundry machine may be fabricated without the cabinet configured to define the exterior appearance of the laundry machine. Even in this case, the front part of the cabinet may be formed. 
     Advantageous Effects of Invention 
     The present invention has following an advantageous effect. 
     According to the laundry machine of the present invention, a drum type laundry machine having a totally different new structure is provided. As a result, the vibration of the drum is not transmitted to the tub and it may be suspendingly supported. 
     Furthermore, according to the laundry machine of the present invention, the structure is changed to increase a washing capacity and the load of the tub having the increased capacity is supported vertically. As a result, stability of the tub supporting structure may be improved advantageously. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are included to provide further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure. 
       In the drawings: 
         FIG. 1  an exploded perspective view illustrating a laundry machine according to an exemplary embodiment of the present invention; 
         FIGS. 2 and 3  are perspective view illustrating a tub front of the laundry machine; 
         FIG. 4  is a rear perspective view illustrating a tub rear of the laundry machine; 
         FIG. 5  is a perspective illustrating a suspension of the laundry machine; 
         FIG. 6  is a side view illustrating a coupling state between the tub and the suspension provided in the laundry machine; 
         FIG. 7  is a rear perspective view illustrating a tub back of the laundry machine according to the present invention. 
         FIG. 8  is a front perspective view illustrating the tub back of the laundry machine according to the present invention; 
         FIG. 9  is a front perspective view illustrating a bearing housing of the laundry machine according to the present invention; 
         FIG. 10  is a rear perspective view illustrating the bearing housing of the laundry machine according to the present invention; 
         FIG. 11  is a perspective view illustrating a coupling state between the tub back and the bearing housing of the laundry machine according to the present invention; and 
         FIG. 12  is a perspective view illustrating a coupling state between the tub back and a stator. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Reference will now be made in detail to the specific embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 1  is an exploded perspective view illustrating a laundry machine according to an exemplary embodiment of the present invention. 
     As shown in  FIG. 1 , the laundry machine includes a tub fixedly installed in a cabinet  60 . The tub  10  includes a tub front  100  configured to define a front of the tub  10  and a tub rear  120  configured to define a rear of the tub  10 . The tub front  100  and the tub rear  120  are assembled by screws and a predetermined space is formed in the assembled tub front and tub rear  120  to accommodate a drum  30 . The tub  10  may further include a tub back configured to form a rear surface of the tub  10  and the tub back is connected with the tub rear  120  via a rear gasket  250 . The rear gasket  250  may be made of flexible material not to transmit the vibration of the tub back  130  to the tub rear  120 . 
     The cabinet defines an exterior appearance of the laundry machine and it includes a cabinet front (not shown), a cabinet rear  620 , a cabinet left  640 , a cabinet right  630 , a cabinet top (not shown) and a cabinet base  600 . 
     The tub rear  120  has a rear surface  128  and the rear surface  128  of the tub rear  120 , the tub back  130  and the rear gasket  250  forms a rear surface of the tub  10 . The rear gasket  250  is sealed and connected with both of the tub back  130  and the tub rear  120 , such that wash water inside the tub  10  may not leak. The tub back  130  is rotated together with the drum  30  when the drum  30  is rotated. At this time, the tub back  130  is distant from the tub rear  120  a predetermined distance not to interfere with the tub rear  120 . Since the rear gasket  250  is made of flexible material, the tub back  130  is relative-moved, not interfering with the tub rear  120 . The rear gasket  250  may include a corrugated part ( 252 , see  FIG. 4 ) extendible enough to enable this relative-motion. 
     A foreign substance preventing material  200  is provided in a front part of the tub front  100  to prevent foreign substances from coming between the tub  10  and the drum  30 . The foreign substance preventing material  200  is flexible material and it is fixedly installed to the tub front  100 . Here, the foreign substance preventing material  200  may be made of a predetermined material identical to the material of rear gasket  250 . 
     The drum  30  is configured of a drum front  300 , a drum center  320  and a drum back  340 . Ball balancers may be installed in front and rear parts of the drum  30 , respectively. The drum back  340  is connected with a spider  350  and the spider  350  is connected with a shaft  351 . The drum  30  is rotated in the tub  10  by a rotational force transmitted via the shaft  351 . 
     The shaft  351  is directly connected with a motor, passing through the tub back  130 . Specifically, a rotor (not shown) of the motor is directly connected with the shaft  351 . A bearing housing  400  is coupled to the rear surface  128  of the tub back  130  and the bearing housing  400  rotatably supports the shaft  351 , located between the motor and the tub back  130 . 
     A stator is fixedly installed in the bearing housing  400  and the rotor is located around the stator. As mentioned above, the rotor is directly connected with the shaft  351 . Here, the motor may be an outer rotor type motor connected with the shaft  351  directly. 
     A suspension unit ( 40 , see  FIG. 5 ) located from the cabinet base  600  to support the bearing housing  400 . The suspension unit  40  includes three spring cylinder dampers  500 ,  5100 , and  520  and two cylinder dampers  530  and  540  configured to obliquely support the bearing housing  400  in a forward and backward direction. The suspension unit  40  is connected to the cabinet base  600  flexibly to allow the drum  30  to move in forward/backward and rightward/leftward directions, not completely fixed to the cabinet base  600 . 
     That is, the suspension unit  40  is flexible enough to allow the predetermined forward/backward and rightward/leftward rotation of the drum  30  with respect to the supporting point of the suspension unit connected with the cabinet base  600 . Perpendicular suspensions may be installed in the cabinet base  600  in the media of a rubber bushing (not shown). Perpendicular ones of the suspensions are used to suspend the vibration of the drum  30  elastically and oblique ones of them are used to dampen the vibration of the drum  30 . That is, the perpendicular one is employed as spring out of a vibration system including a spring and damping means and the oblique ones as damping means. 
     The other parts of the tub  10  may be fixedly installed to the cabinet, except the tub back  130  and the vibration of the drum  30  is suspended and supported by the suspension unit. Substantially, each of the tub  10  and the drum  30  has a separate supporting structure. Even if the drum  30  is vibrated, the tub  10  may not be vibrated. 
     As follows, each element will be described in detail. 
       FIGS. 2 and 3  are diagrams illustrating the tub front  100 . The tub front  100  includes a donut-shaped perpendicular front surface provided in a front portion of a cylindrical surface composing a predetermined portion of a side wall of the tub. A rear portion of the cylindrical surface is open as it is and the rear portion includes a plurality of securing holes  110  formed therein. The securing holes  110  are secured to corresponding securing holes ( 127 , see  FIG. 4 ) of the tub rear  120 . 
     A rim part  101  is extended forward from an inner circumferential surface of the front surface of the tub front  100 . The width of the rim part  101  is getting narrower downward from the top and substantially the rim part  101  may not be formed at a lower portion of an inner corner of the front surface. 
     In the rim part  101  may be formed a water supply inlet  104  configured to supply wash water, a hot air inlet  103  which will be used in a drying course, a circulating-water inlet  106  configured to drawn the wash water circulated by a circulation pump there through and a steam inlet  105  configured to draw steam there through. 
     Since the vibration of the tub  10  is noticeably reduced in the laundry machine according to the present invention, a water supply structure of a water supply hose, a drying structure of a drying duct and a steam supply structure, a circulating-water supply structure and the like may be implemented stably. 
     The hot air inlet  103  may be extended from the rim part  101  approximately in a square shape. Here, the hot air inlet  103  is required by a laundry machine having washing and drying functions and not by a laundry machine having no drying function. 
     The water supply inlet  104 , the hot air inlet  103  and the like are formed in the front part of the tub front  100 . Because of that, the supply of wash water, hot air and the like may be implemented in the front part of the tub  10 . 
     The water supply inlet  104  and the other components may be located more forwardly than a front end of the drum  30  accommodated in the tub  10 . As a result, the wash water, hot air and the like may be directly drawn into the drum  30  via the opening of the drum  30  configured to load the laundry therein or there out. Since fluidal material supplied to treat the laundry such as the wash water and hot air may be directly drawn into the drum  30  and this enables the laundry to be treated more efficiently. 
     In case detergent is supplied via a detergent box, together with the wash water, the detergent is directly drawn into the drum  30  and the amount of used detergent may be reduced accordingly, such that the amount of wash water may be reduced. 
     Here, a problem of tub contamination generated by detergent remnant loaded in a bottom of the tub may be solved. In case water is supplied from the front part of the tub, a door glass (not shown) may be washed by the supplied water advantageously. 
     Even if hot air is supplied via the front portion of the tub, a perpendicular surface of the tub front  100 , that is, a front surface thereof, the hot air flow may be ‘⊂’-shaped, which is a complex air path formed by the hot air re-bent toward a perpendicular front surface of the tub after hot air having flown from the rear portion of the tub is bent downward from a front portion of a upper part of the tub. This ‘⊂’-shaped air path will not be helpful to efficient hot air flow. However, when the hot air inlet  103  is formed in the rim part  101  of the tub front  100 , the hot air may be bent perpendicularly one time and it may flow smoothly. 
     The water supply inlet  104  and the other holes may be located beyond a center of the drum. Because of that, the wash water and the like may be supplied to the drum inside from a front upper portion of the drum. If it is necessary to supply the wash water and the like to the drum inside from a front lower portion of the drum, the rim part  101  of the tub front  100  may be formed in a lower portion of the front surface part  112 . if it is necessary to supply the wash water and the like in a right and left direction, not in the upward and downward direction mentioned above, the rim part  101  may be formed in a inner corner center portion  131  of the front surface part  112 . That is, the appearance of the rim part  101  may be variable according to which direction the supplied fluidal material is supplied along. 
     A coupling part  102  is formed in the rim part  101  to couple the foreign substance preventing material  200  to the tub front  100 . The coupling part  102  is extended forward from the front end of the rim part  101 , having a small cylindrical surface-like shape. Ribs  102   a  are formed in an outer circumferential surface of the small cylindrical surface. 
     Once the coupling part  102  is inserted in the foreign substance preventing part  200 , the foreign substance preventing part  200  may be coupled to the coupling part  102 . for that, inserting recesses (not shown) are formed in the foreign substance preventing material  200  and the small cylindrical surface having the ribs  102   a  formed therein is inserted in the inserting recess (not shown). 
     The tub front  100  is fixedly coupled to the cabinet front (not shown) and coupling bosses  107   a ,  107   b ,  107   c  and  107   d  are formed in the front surface of the tub front  100  for such the fixed coupling, approximately surrounding the rim part  101 . After the cabinet front (not shown) is located in a state of the tub front  100  installed, screws are fastened backward to couple the tub front  100  to the cabinet front. 
       FIG. 3  is a rear view illustrating an inside of the tub front  100 . The steam inlet  105  may be connected with a seam hose. A steam guide  105   a  is formed in the tub front  100  to guide steam drawn via the steam inlet  105  toward a drum inside and a circulating-water guide  106   a  is formed in the tub front  100  to guide circulating-water drawn via the circulating-water inlet  106  toward the drum inside. The steam inlet  105 , the circulating-water inlet  106 , the steam guide  105   a , the circulating-water guide  106  and the like may be integrally formed with the tub front  100 . The tub front  100  is plastic-injection-molded and the steam inlet  105  and the other components may be injection-molded as some parts of the tub front  100 . 
     The tub front  100  is coupled to the tub rear  120  to form a predetermined space configured to accommodate the drum  30 . Here, the tub front  100  and the tub rear  120  may be screw-fastened to each other. For this screw-fastening, a plurality of screw-securing holes  110  may be formed along a circumference of the rear part of the tub front  100 . 
       FIG. 4  is a diagram illustrating the connection among the tub front  100 , the tub rear  120 , the tub back  130  and the rear gasket  250 . 
     The tub rear  120  is cylindrical-shaped to surround the drum  30  and a front part of the tub rear is open and a rear part of the tub rear includes a donut-shaped rear surface  128 . The front part is sealing-coupled to the tub front  100 . A diameter of the rear surface  128  of the tub rear  120  is larger than an outer diameter of the tub back  130 . Even when the tub back  130  is vibrated, the tub back  130  is distant from the tub rear  120  enough not to interfere with the rear surface  128  of the tub rear  120 . 
     The rear gasket  250  is provided between the rear surface  128  of the tub rear  120  and the tub back  130 . The rear gasket  250  seals the rear surface  128  of the tub rear  120  and the tub back  130  and it includes a corrugated part  252  flexible enough not to interfere with the vibration of the tub back  130 . 
     A hot air inlet  121  is formed in a predetermined portion of the tub rear  120  in case of the laundry machine having washing and drying functions. In case of the laundry machine only having the washing function, the hot air outlet  121  may be not provided, of course. 
     An auxiliary structure configured to fixedly support the tub with respect to the base is formed in lower parts of the tub rear  120  and the tub front  100 . 
       FIG. 5  is a diagram illustrating the suspension unit  40  mounted on the base  600 .  FIG. 6  illustrates a coupling state among the tub  100  and  120 , the bearing housing  400  and the suspension unit  40 . 
     The bearing housing  400  include a bearing supporting part  401  configured to support a bearing. A tub back securing part  407  configured to secure the tub back  250  thereto is formed in a front portion of the bearing housing  400  and a stator securing part  402  configured to secure the stator of the motor thereto is formed in a rear portion of the bearing housing  400 . 
     Here, the suspension unit  40  includes a first oblique bracket  431 , a second oblique bracket  430 , a first suspension bracket  450  and a second suspension bracket  440 . 
     A first extending part  406   a  and a second extending part  406   b  extended from right and left side portions of the bearing housing  400  in a radius direction, respectively. The first oblique bracket  431  and the second oblique bracket  430  are connected to the first extending part  406   a  and the second extending part  406   b , respectively. The first suspension bracket  450  and the second suspension bracket  440  are connected to the first oblique bracket  431  and the second oblique bracket  430 , respectively. 
     Here, the shapes of the first extending part  406   a , the first oblique bracket  431 , and the first suspension bracket  450 , the second extending part  406   b , the second oblique bracket  430  and the second suspension bracket  440  are corresponding to each other. When the laundry is loaded in the drum, the first and second oblique brackets  431  and  430  are used to balance the center of gravity and they are used as mass in the vibration system of the drum. 
     The suspension unit  40  includes a first spring cylinder damper  520 , a second spring cylinder damper  510  and a third spring cylinder damper  500  which are arranged vertically for the vertical suspension and a first cylinder damper  540  and a second cylinder damper  530  which are arranged obliquely for the backward suspension. 
     Here, a single one of the first spring cylinder damper  520 , the second spring cylinder damper  510  and the third spring cylinder damper  500  may be arranged in a rear portion and the other two may be arranged in front right and left portions with respect to a center of the base  600 . The first cylinder damper  540  and the second cylinder damper  530  may be arranged oblique forward and backward from rear right and left sides with respect to the center of the base  600 , respectively. 
     Specifically, the first spring cylinder damper  520  is connected between the first suspension bracket  450  and the base  600 . The second spring cylinder damper  510  is connected between the second suspension bracket  440  and the base  600 . The third spring cylinder damper  500  is directly connected between the bearing housing  400  and the base  600 . 
     The first cylinder damper  540  is obliquely installed between the first suspension bracket  450  and a rear portion of the base and the second cylinder damper  530  is obliquely installed between the second suspension bracket  440  and a rear portion of the base  600 . 
     That is, the third spring cylinder damper  500  is arranged in a center of the rear portion and the first spring cylinder damper  520  and the second spring cylinder damper  510  are arranged in right and left sides of the rear portion. The first cylinder damper  540  and the second cylinder damper  530  are located on right and left sides of the third spring cylinder damper  500 . That is, the spring cylinder dampers  500 ,  510  and  520  and the cylinder dampers  530  and  540  are vertically symmetrical. 
     As follows, the structure of the tub back  130  will be described in reference to  FIGS. 7 and 8 . 
       FIG. 7  is a rear-respective view illustrating the tub back  130  of the laundry machine according to the present invention and  FIG. 8  is a front perspective view illustrating the tub back  130  of the present invention according to the present invention. 
     As shown in  FIGS. 7 and 8 , the tub back  130  according to the present invention is coupled to the rear part of the tub rear  120  by the rear gasket  250 . For that, the rear gasket  250  is formed in a small disc which is smaller than a hollow formed in the tub rear  120 . 
     A through hole  131  is formed in a center portion of the tub back  130  to pass the shaft  351  connected to the drum  30  there through. A gentle curvature surface  132  is formed in the front surface of the tub back  130 , that is toward the inside of the tub  10 , with a convex outer circumference of the through-hole  131 . A plurality of ribs  134  and  135  and bosses  138  and  139  may be formed in the rear surface of the tub back  130  to reinforce the rigidity of the tub back  130  and the coupling with the bearing housing  400 . 
     As shown in  FIG. 7 , the through-hole  131  is formed in the rear surface of the tub back  130  through the center of the tub back  130  and the shaft  351  configured to rotate the drum  30  passes through the through-hole  131 . 
     The plurality of the ribs  134  and  135  may be formed along an outer circumferential surface of the through-hole  131  to reinforce the rigidity of the tub back  130 . the ribs  134  and  135  includes radial ribs  134  extended from the through-hole  131  in a radial shape and circular ribs  135  loaded from the through-hole  131  in a circular shape. The number of the radial ribs  134  and the circular ribs  135  may be increased or decreased to reinforce the rigidity of the tub back  130 . 
     A rim part  136  having a predetermined height is formed in an outer circumferential surface of the tub back  130 . A coupling part (not shown) is formed in an outer circumferential surface of the rim part  136  to couple the tub back  130  to the rear gasket  250  and a water wall  137  is formed in an upper portion of the rim part  136  of the tub back  130  to prevent water having leaked through the outer circumference of the tub back from flowing into the motor located in the center of the tub back. 
     In the meanwhile, A plurality of coupling bosses  138  may be formed in the radial ribs  134  and the circular ribs  135  to couple the bearing hosing  400  to the tub back  130 . The coupling bosses may be formed in intersection points of the radial ribs  134  and the circular ribs  135 . 
     A plurality of auxiliary bosses may be further formed in the outer portion of the tub back  130  for auxiliary coupling with the bearing housing  400 . The auxiliary bosses  139  may be vertically symmetrical with respect to the through-hole  131 . It is preferable that the auxiliary bosses  139  may be formed at intersection points of the radial ribs  134  and the circular ribs  135 , respectively. These coupling bosses  138  and the auxiliary bosses  139  couple the bearing house to the tub back  130  in outward and inward directions, only to prevent deformity of the tub back  130 . 
     As shown in  FIG. 8 , the through-hole  131  is formed in the center of the front surface of the tub back  130 , passing through the tub back  130 , and the shaft  351  configured to rotate the drum  30  passes through the through-hole  131 . A circular inserting rim part  131   a  is projected forward along the inner circumferential surface of through-hole  131  and the spider  350  includes a recessed portion in which the inserting rim part  131   a  is inserted. A circumferential rear surface surrounding the through-hole  131  is seated on a front surface of a bearing supporting part  401  of the bearing housing  400 . A portion of a waterseal is placed between the circumferential rear surface surrounding the through-hole  131  and the front surface of a bearing supporting part  401  to prevent water from leaking between the tub back and the bearing housing. 
     In the meanwhile, the gentle curvature surface  132  projected toward the drum is formed in an outer circumference of the through-hole formed in the front surface of the tub back  130 . 
     The gentle curvature surface  132  prevents the drum from contacting with the tub back  130  according to a rotational radius and a vibration radius of the drum  30  when the drum  30  connected with the shaft  351  is vibrated. That is, when there is vibration of the drum  30 , the drum  30  is vibrated with respect to the shaft  351  and a rear outer circumferential surface of the drum happens to contact with a rear outer circumferential surface of tub  10  accordingly. Because of that, the distance between an external rear outer circumferential surface of the tub  10  and the drum  30  has to be wider than the distance between a rear center of the tub  10  and the drum  30 . 
     In addition, the gentle curvature surface  132  is provided to prevent the contact between the tub back and the drum and simultaneously to secure the coupling space of the bearing housing  400  coupled to the outer surface of the tub back  130 . that is, the center of the tub back  130 , which is a portion of the tub back the bearing housing  400  is coupled to, is recessed toward the inside of the tub  10  and the rear space of the tub back  130  is increased. This gentle curvature surface  132  may enable the rear portion of the tub slim and compact. That is, the rear portion of the tub back  130  is internally recessed as much as the center front surface of the tub back  130  is recessed toward the tub inside by the gentle curvature surface  132 . 
     As follows, the structure of the bearing housing  400  provided in the laundry machine according to the present invention will be described in reference to  FIGS. 9 and 10 . 
       FIG. 9  is a front perspective view illustrating the bearing housing of the laundry machine according to the present invention and  FIG. 10  is a rear perspective view illustrating the bearing housing of the laundry machine according to the present invention. 
     As shown in  FIG. 9 , the bearing housing  400  includes a bearing supporting part  401  configured to support a bearing, a tub back coupling part ( 425 , see  FIG. 8 ) configured to couple the tub back  130  to the bearing housing and a stator coupling part  402  configured to couple a stator (MS, see  FIG. 12 ) to the bearing housing  400 . 
     Here, the tub back coupling part  425  and the stator coupling part  402  are extended from the bearing supporting part  401  in a radial direction, integrally formed with bearing supporting part  401 . 
     The tub back coupling part  425  and the stator coupling part  402  may be formed by zigzagged middle ribs  421  extended from the bearing supporting part  401  in a radial direction. This middle ribs  421  are alternatively projected and recessed like corrugation along a circumferential direction. Predetermined ones of the middle ribs  421  toward the front surface may form the tub coupling part  425  and the other ones toward the rear surface may form the stator coupling part  402 . 
     A ring-shaped outer circumferential rib  420  is formed in an outer circumferential surface of the middle rib  421  of the tub back coupling part  425  and the stator coupling part  402 . Here, the outer rib  420  forms an exterior appearance of the bearing housing  400  and it may be thicker than the middle rib  421 . This is because the first and second extending parts  406   a  and  406   b  are extended from both sides of the bearing housing  400  in the radial direction. That is, the outer rib  420  is provided to secure enough rigidity, because the extending parts  406   a  and  406   b  are integrally formed with each other. The forward and backward width of the outer rib  420  may be larger than the thickness of the extending parts  406   a  and  406   b.    
     Also, the projected portion of the tub back coupling part  425  is corresponding to the recessed portion of the stator coupling part  40  and the projected portion of the stator coupling part  402  is corresponding to the recessed portion of the tub back coupling part  425 . This structure may reduce the amount of material composing the bearing housing  400  and secure enough rigidity. 
     The tub back  130  is seated in tub back coupling part  425  which is a front surface portion of the bearing housing  400  and a stator (MS) is coupled to the stator coupling part  402  which is a rear surface portion of the bearing housing. 
     In an aspect of the coupling, the tub back coupling part  425  and the stator coupling part  402  should have the minimum thickness required to couple the bearing housing to the tub back  130  and the stator (MS). If there is no other limitations, for example, no rigid problems, a forward/backward width of the middle rib from the position of the boss configured to couple the stator (MS) or the tub back  130  may be identical to the length of the boss. 
     The laundry machine according to the present invention may not have the fixedly connected or coupled structure between the bearing housing  400  and the tub. As a result, relatively small load is applied to the stator coupling part  402 . 
     Different from the conventional laundry machine, the forward/backward width of the stator coupling part  402 , especially, where the boss is located for the coupling of the stator, may be determined by the length of the boss. As the forward and backward width of the stator coupling part  402  is getting smaller, the slim and compact structure of the laundry machine may be getting easier to achieve. 
     In reference to  FIG. 9 , the tub back coupling part  425  will be described. A front gentle curvature part  407  having a gentle curvature surface extended from the bearing housing  400  in a radial direction is formed in the projected portions of the front surface of the bearing housing  400 , that is, the surface of the bearing housing which is a tub-toward surface of the middle rib  421  extended from the bearing supporting part  401  The tub back coupling part  425 . 
     A coupling hole  405  is formed in the front curvature part  407  to couple the bearing housing  400  to the tub back  130 . As they are getting farther from the center with respect to the radial direction, the radially extended portions from the front curvature part  407  out of the projected portions of the front surface of the bearing housing  400  may be getting more oblique backward. 
     The coupling holes  405  may be formed in centers of the predetermined recesses, respectively. This is for the coupling after protrusions (not shown) formed in the tub back  130  are inserted in the recesses to adjust the location of the tub back  130  smoothly. 
     The coupling of the bearing housing with tub back  130  is implemented in a state of the rear surface of the tub back  130  being in close contact with the tub back coupling part  425  of the bearing housing  400 . At this time, the rear surface of the tub back  130  is formed correspondingly to the front surface of the tub back coupling part  425  to be in close contact with each other. here, the tub back  130  and the bearing housing  400  are coupled to each other by an auxiliary coupling material ( 405   a ) passing through the bearing housing  400  from the rear portion, for example, a bolt. 
     At this time, the coupling material configured to secure the tub back  130 , for example, a bolt and the like may be inserted in one of the tub back coupling holes  405  formed in the tub-back-toward projected one of the middle ribs  421  extended from the bearing supporting part  401 , only to secure the tub back  130 . That is, the coupling material configured to securely couple the tub back  130  may be inserted more internal than the location of the stator coupling part  402 , to securely couple the tub back  130 . As a result, when the stator is coupled, the coupling material for the tub back  130  may not interfere with the stator (MS) (see  FIG. 11 ). 
     In the meanwhile, the tub back coupling holes  405  may be formed outer to the bearing supporting part  401  of the above bearing housing  400  to be coupled with the coupling bosses  138 . Auxiliary holes (not shown) may be formed in the first and second extending parts  406   a  and  406   b  of the bearing housing to be coupled to the auxiliary coupling bosses  139 , respectively. 
     In reference to  FIG. 10 , the stator coupling part will be described. The stator coupling part  402  is formed by the projected portion of the rear surface of the bearing housing  400 , which is an opposite surface toward the tub inside out of the middle ribs extended from the bearing supporting part  401 . 
     Six stator coupling bosses  404  are formed in the stator coupling part  402  to couple the stator  80  thereto. The coupling bosses  404  are formed along a circumference of the middle rib  421 . 
     Projected portions of the rear surface of the stator coupling part  420  may be stepped in a radial direction. That is, there may be a predetermined portion extended from the bearing supporting part  401  in a radial direction and another portion bent forward from the extended portion and a further portion re-extended from the bent portion in a radial direction (hereinafter, a rear plane part  409 ). The reason why the stator coupling part  402  is stepped is that the position of the stator (MS) has to be limited when the stator (MS) is coupled. 
     The rear plane parts  409  may be placed on the same single plane in a radial direction. The rear plane parts  409  may be portions in which the stator coupling bosses  404  will be located. That is, the stator (MS) may be coupled to the stator coupling bosses  404  formed in the rear plane part  409  by an auxiliary coupling material  404   a , for example, a bolt and the like. As a result, the coupling position of the tub back  130  mentioned above is different from the coupling position of the stator (MS) such that the coupling of the tub back  130  may not interfere with the coupling of the stator (MS) (see,  FIG. 12 ). 
     The gentle curvature part  407  having the coupling holes  405  formed therein may be formed in the front surface of the stator coupling part  402  and the rear plane part  409  formed distant from the bearing supporting part  401  in the radial direction may be formed in the rear surface of the stator coupling part  402 . Here, an outer circumference of the rear plane part  409  may be identical to or larger than an outer circumference of the front gentle curvature part  407 . 
     It will be apparent to those skilled in the art that various modifications and variations can be made in 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.