Patent Publication Number: US-10316453-B2

Title: Top-loading type washing machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Korean Patent Application No. 10-2015-0139270, filed on Oct. 2, 2015 and Korean Patent Application No. 10-2015-0139271 filed on Oct. 2, 2015 in the Korean Intellectual Property Office, the disclosure of each is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a top-loading-type washing machine having pulsators. 
     2. Description of the Related Art 
     Generally, a washing machine is an apparatus that washes laundry using, for example, de-emulsification of detergent, a water stream generated by rotation of a wash tub or a wash blade, and shocks applied by the wash blade, and performs washing, rinsing, or dehydration to remove contaminants adhered to laundry (hereinafter also referred to as “fabric”) using the action of detergent and water. 
     A conventional top-loading-type washing machine includes a pulsator placed inside a drum. 
     The pulsator may be rotated independently of the drum. A conventional pulsator may be rotated along with the drum, or may be rotated in the opposite direction as the drum. 
     When the drum and the pulsator are rotated in opposite directions, power consumption is high, but the washing force that is exhibited is not commensurate with the amount of power that is consumed. 
     SUMMARY 
     It is one object of the present disclosure to provide a top-loading-type washing machine in which two pulsators are installed. 
     It is another object of the present disclosure to provide a top-loading-type washing machine in which an inner pulsator and an outer pulsator are installed. 
     It is another object of the present disclosure to provide a top-loading-type washing machine in which an inner pulsator and an outer pulsator may be rotated in opposite directions. 
     It is another object of the present disclosure to provide a top-loading-type washing machine which exhibits low power consumption during the operation of an inner pulsator and an outer pulsator. 
     It is another object of the present disclosure to provide a top-loading-type washing machine in which the rotation speeds of an inner pulsator and an outer pulsator are variable depending on the size of the laundry load. 
     It is another object of the present disclosure to provide a fastening structure capable of coupling an inner pulsator to a drive shaft. 
     It is another object of the present disclosure to provide a fastening structure for coupling an inner pulsator to a drive shaft so that the inner pulsator is rotated relative to the drive shaft, rather than being rotated along with the drive shaft. 
     It is another object of the present disclosure to provide a fastening structure having a long-axis bolt that penetrates an inner pulsator and is fastened to a drive shaft. 
     It is a further object of the present disclosure to provide a fastening structure which is rotatably fastened to a drive shaft and is rotated relative to an inner pulsator so as to minimize friction with the rotating inner pulsator. 
     In accordance with an aspect of the present disclosure, the above and other objects can be accomplished by the provision of a top-loading-type washing machine including a drum in which vertically introduced laundry is loaded, a drive module for rotating the drum via a drive shaft, an inner pulsator located on the drive shaft, the inner pulsator being rotated by torque from the drive module, an outer pulsator placed in the drum, the outer pulsator located below the inner pulsator, the outer pulsator being rotated in a direction opposite to that of the inner pulsator by torque from the drive module, and a gearbox connected to the drive shaft so as to receive torque from the drive module, the gearbox rotating the inner pulsator and the outer pulsator in opposite directions. 
     The gearbox includes a sun gear connected to and rotating with the drive shaft, a plurality of planetary gears engaged with the sun gear, each of the planetary gears rotating on its own rotation axis while traveling along an outer circumferential surface of the sun gear, a ring gear engaged with the planetary gears so as to perform rotation, a carrier for providing the rotation axis of each planetary gear and for connecting the planetary gears to one another, the carrier being rotated along with the planetary gears when the planetary gears travel along the outer circumferential surface of the sun gear, a gear housing to which the ring gear is fixed, the gear housing being coupled to the outer pulsator for transferring torque, and a carrier shaft formed on the carrier and coupled to the inner pulsator for transferring torque. The carrier shaft has a carrier shaft bore formed therein so as to communicate with an inside of the gearbox. The top-loading-type washing machine further includes a long-axis bolt. The long-axis bolt is fastened at a lower end thereof to the drive shaft, and is inserted into the carrier shaft bore so as to be rotated in the carrier shaft bore. 
     The top-loading-type washing machine according to a first embodiment may further include a top bolt for connecting the inner pulsator and the carrier shaft to each other. The long-axis bolt according to the first embodiment may have an upper end inserted into the carrier shaft bore. 
     The long-axis bolt according to a second embodiment may penetrate the carrier shaft, may have an upper end supported by the inner pulsator, and may be rotated relative to the inner pulsator and the carrier shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a sectional view illustrating the interior of a washing machine according to an embodiment of the present invention; 
         FIG. 2A  is a sectional view illustrating a first embodiment of a dual pulsator illustrated in  FIG. 1 ; 
         FIG. 2B  is a sectional view illustrating a second embodiment of the dual pulsator illustrated in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of the dual pulsator illustrated in  FIG. 1 ; 
         FIG. 4  is a sectional exploded perspective view of a gearbox illustrated in  FIGS. 2A and 2B ; 
         FIG. 5  is a sectional view of the gearbox illustrated in  FIGS. 2A and 2B ; 
         FIG. 6  is a graph illustrating the speed of a planetary gear assembly according to an embodiment of the present invention; 
         FIG. 7A  is a sectional view illustrating a coupling structure of an inner pulsator and a drive shaft illustrated in  FIG. 2A  according to the first embodiment; 
         FIG. 7B  is a sectional view illustrating a coupling structure of an inner pulsator and a drive shaft illustrated in  FIG. 2B  according to the second embodiment; and 
         FIG. 8  is a partially cut-away perspective view of a sealing member illustrated in  FIGS. 7A and 7B . 
     
    
    
     The following description will be based on the embodiments of the present invention, i.e. the first embodiment and the second embodiment.  FIGS. 1, 3 to 6, and 8  are views illustrating common elements of the first embodiment and the second embodiment,  FIGS. 2A and 7A  are views illustrating the configuration of the first embodiment, and  FIGS. 2B and 7B  are views illustrating the configuration of the second embodiment. The elements common to both the first embodiment and the second embodiment are designated by the same reference numerals. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a washing machine according to the present embodiment (i.e., the first embodiment or the second embodiment) includes a casing  10  defining the external appearance of the washing machine, and a control module  20  installed on casing  10 . 
     Control module  20  includes, for example, manipulation keys for receiving manipulation force from a user, and a display for displaying information related to the state of operation of the washing machine. 
     The washing machine includes a tub  30  placed inside casing  10  for storing wash water therein, a drum  40  placed inside tub  30  for storing laundry to be washed, a drive module  50  placed on tub  30  for rotating drum  40  in order to wash the laundry, a water supply module  60  for supplying wash water to tub  30 , a water drain module  70  for discharging wash water stored in tub  30 , a suspension module  80  for reducing or absorbing vibrations generated in tub  30 , and a dual pulsator  90  placed in drum  40  so as to be rotated upon receiving drive power from drive module  50 . 
     Dual pulsator  90  is comprised of an inner pulsator  92  and an outer pulsator  94 . The axis centers of the respective pulsators  92  and  94  are located on the imaginary axis of a drive shaft of drive module  50 . The respective pulsators  92  and  94  are adapted to be rotated in opposite directions. 
     Casing  10  includes a main body  12  in which tub  30  and drum  40  are placed, a top cover  14  located on the top side of main body  12 , and a door formed in top cover  14  for opening or closing the inside of casing  10 . 
     Control module  20  includes, for example, manipulation buttons and a dial for receiving manipulation force from a user. 
     Control module  20  is provided with a display unit (not illustrated) for showing various pieces of information about the washing machine to the user. In the present embodiment, the display unit is located in top cover  14 . 
     Tub  30  is connected to water supply module  60  and stores wash water supplied from water supply module  60 . 
     Tub  30  may be connected to water drain module  70 , and water drain module  70  may discharge the wash water stored in tub  30  outward. 
     Drum  40  is placed inside tub  30 . Drum  40  is rotated upon receiving drive power from drive module  50 . 
     Drum  40  includes a drum body having a cylindrical shape, and a drum base coupled to the bottom side of the drum body. 
     A hub  46  is disposed on the drum base. Drive module  50  may selectively transfer drive power to hub  46 . 
     Drum  40  is configured to be rotated forward or in reverse relative to tub  30 . 
     In the present embodiment, water supply module  60  includes a water supply valve  61  and a water supply path  62 , which are located on top cover  14 . 
     In the present embodiment, water drain module  70  includes a water drain valve  71  connected to tub  30 , and a water drain path  72  connected to water drain valve  71 . 
     Suspension module  80  is connected to tub  30 , and reduces vibrations generated in tub  30  using at least one of elasticity or absorption. 
     In the present embodiment, suspension module  80  is located between casing  10  and tub  30 . Suspension module  80  supports the bottom of tub  30  and hangs from top cover  14 . 
     The structure of dual pulsator  90  according to the present embodiment (i.e. the first embodiment or the second embodiment) will be described with reference to  FIGS. 2A to 8 . 
     In the present embodiment, drive module  50  includes a motor  52  located on the bottom side of tub  30 , a drive shaft penetrating tub  30  and connected to drum  40 , and a gearbox  100  for transferring drive power of drive shaft  54  to dual pulsator  90 . 
     Drive shaft  54  is disposed to penetrate hub  46 . 
     Drive shaft  54  may be selectively connected to hub  46  of drum  40 . Thus, only drum  40  may be rotated by drive module  50 . 
     Drive shaft  54  may be selectively connected to gearbox  100 . 
     When drive shaft  54  and gearbox  100  are connected to each other, dual pulsator  90  may be rotated. 
     Dual pulsator  90  is located at the upper side of hub  46 . 
     Dual pulsator  90  includes inner pulsator  92  and outer pulsator  94 . Inner pulsator  92  is located at the inner side of outer pulsator  94 . 
     Inner pulsator  92  has a circular shape when viewed in a plan view. 
     Outer pulsator  94  has a ring shape when viewed in a plan view. 
     An installation hole  95  in which inner pulsator  92  is rotated is defined inside outer pulsator  94 . 
     Inner pulsator  92  and outer pulsator  94  may be rotated in different directions from each other. 
     In the present embodiment, dual pulsator  90  further includes a pulsator base  96  located at the lower side of inner pulsator  92 . Pulsator base  96  and outer pulsator  94  are defined as an outer assembly. 
     Inner pulsator  92  is located above outer pulsator  94 . Inner pulsator  92  is rotated above outer pulsator  94 . 
     Inner pulsator  92  may be provided with an upwardly protruding wash blade  91 . In the present embodiment, three wash blades  91  are arranged at an angular interval of 120 degrees when viewed in a plan view. 
     Outer pulsator  94  may also be provided with an upwardly protruding wash blade  93 . In the present embodiment, six wash blades  93  are equidistantly arranged when viewed in a plan view. 
     Inner pulsator  92  is located on the center of outer pulsator  94  when viewed in a plan view. Rotation centers of inner pulsator  92  and outer pulsator  94  are located on drive shaft  54 . 
     Installation hole  95  is defined inside outer pulsator  94 . An installation groove  97  is formed in the inner edge of outer pulsator  94  defining installation hole  95 . A portion of inner pulsator  92  is inserted into installation groove  97 . 
     Pulsator base  96  is located below installation hole  95 . Pulsator base  96  covers installation hole  95 . Pulsator base  96  is fixed to outer pulsator  94 . 
     Gearbox  100  of drive module  50  is located below pulsator base  96 . Gearbox  100  located between pulsator base  96  and hub  46 . Gearbox  100  penetrates pulsator base  96  and is connected to inner pulsator  92 . 
     Gearbox  100  is connected to motor  52  of drive module  50  and receives drive power. Drive shaft  54  of drive module  50  is also connected to gearbox  100 . 
     Gearbox  100  is connected to each of inner pulsator  92  and outer pulsator  94 . Gearbox  100  may be selectively connected to motor  52 . 
     Gearbox  100  may receive drive power of motor  52  and transfer the drive power to inner pulsator  92  and outer pulsator  94 . 
     Gearbox  100  rotates inner pulsator  92  and outer pulsator  94  in opposite directions. Gearbox  100  may rotate inner pulsator  92  and outer pulsator  94  at different speeds. 
     Gearbox  100  may rotate inner pulsator  92  and outer pulsator  94  at different speeds depending on the size of the laundry load even if constant drive power is input from motor  52 . 
     Gearbox  100  includes a sun gear  110  rotatably connected to drive shaft  54  of motor  52 , a plurality of planetary gears  120  rotatably engaged with sun gear  110 , a ring gear  130  rotatably engaged with planetary gears  120 , a carrier  140  for connecting planetary gears  120  to one another, and a gear housing  150  to which ring gear  130  is fixed, sun gear  110 , planetary gears  120  and carrier  140  being placed inside gear housing  150 . 
     Sun gear  110 , planetary gears  120 , ring gear  130 , and carrier  140  are defined as a planetary gear assembly. The constituent elements of the planetary gear assembly are engaged with or coupled to each other, and therefore may be systematically operated when sun gear  110  is rotated. 
     In the present embodiment, carrier  140  is operated in a non-constrained free state. 
     Sun gear  110  is coupled to drive shaft  54 . Sun gear  110  is provided on inner and outer sides thereof with gear teeth. 
     Sun gear  110  has a sun gear bore  111  vertically formed therein. The inner circumferential surface of sun gear  110  defining sun gear bore  111  is provided with inner teeth  112 . Outer teeth  114  are formed on the outer circumferential surface of sun gear  110 . 
     Drive shaft  54  is inserted into sun gear bore  111 . Drive shaft  54  is engaged with inner teeth  112 . Drive shaft  54  has a serrated shape. 
     Planetary gears  120  are arranged around sun gear  110 . 
     Planetary gears  120  may rotate on their axes while rotating along the circumference of sun gear  110 . To rotate on its axis, each planetary gear  120  has a planetary gear bore  121  vertically formed therein. 
     Planetary gear  120  may rotate about planetary gear bore  121 . In addition, planetary gear  120  may rotate along outer teeth  114  of sun gear  110 . 
     In the present embodiment, six planetary gears  120  are arranged. Each planetary gear  120  is engaged with outer teeth  114  of sun gear  110 . Sun gear  110  and planetary gears  120  are horizontally arranged. 
     Ring gear  130  is located at the outer side of planetary gears  120 . 
     In the present embodiment, ring gear  130  is fixed inside gear housing  150 . 
     Ring gear  130  has a ring shape. Ring gear  130  has teeth formed on the inner circumferential surface thereof. Ring gear  130  is engaged with all of planetary gears  120  at the same time. 
     Planetary gears  120  are located between ring gear  130  and sun gear  110 , and are simultaneously engaged with ring gear  130  and sun gear  110 . 
     Carrier  140  connects planetary gears  120  to one another. Planetary gears  120  may be rotated at the same speed by carrier  140 . 
     Carrier  140  includes a lower carrier body  142 , an upper carrier body  144 , and a carrier shaft  160  formed on upper carrier body  144  so as to penetrate gear housing  150  and be coupled to inner pulsator  92 . 
     Sun gear  110  and planetary gears  120  are located between upper carrier body  144  and lower carrier body  142 . 
     Lower carrier body  142  is located below planetary gears  120 . 
     Upper carrier body  144  is located above planetary gears  120 . 
     In the present embodiment, a planetary gear shaft  141  is formed on lower carrier body  142 . Planetary gear shaft  141  is inserted into planetary gear bore  121 . Planetary gear  120  rotates about planetary gear shaft  141 . 
     A plurality of planetary gear shafts  141  are arranged on lower carrier body  142  in a circumferential direction. Planetary gear shafts  141  are equidistantly arranged in the circumferential direction. 
     Sun gear  110  is also located above lower carrier body  142 . Sun gear  110  is rotated above lower carrier body  142 . 
     Lower carrier body  142  is provided with a lower sun gear recess  146 , into which sun gear  110  is inserted. Drive shaft  54  is also inserted through lower sun gear recess  146 . Drive shaft  54 , inserted through lower sun gear recess  146 , is coupled to sun gear  110 . 
     Upper carrier body  144  is located above lower carrier body  142 . Sun gear  110  supports upper carrier body  144 . Upper carrier body  144  and lower carrier body  142  are coupled to each other. 
     Upper carrier body  144  has an upper sun gear recess  147  formed in the lower surface thereof, into which a portion of sun gear  110  is inserted. Upper carrier body  144  further has a planetary gear shaft recess  148  formed in the lower surface thereof, into which planetary gear shaft  141  is inserted. 
     Upper carrier body  144  and lower carrier body  142  are assembled with each other and operate integrally with each other. 
     Carrier shaft  160  protrudes upward from upper carrier body  144 . Inner pulsator  92  is rotatably connected to carrier shaft  160 . 
     Carrier shaft  160  has a carrier shaft bore  161  formed therein. Carrier shaft bore  161  is formed in the center of carrier shaft  160 . 
     Carrier shaft  160  penetrates gear housing  150  and protrudes upward from gear housing  150 . 
     Although two separate carrier bodies are fabricated in the present embodiment, a single carrier body may be fabricated. When the single carrier body is fabricated, all of planetary gear shafts  141  and carrier shaft  160  are formed on the single carrier body. 
     Gear housing  150  is comprised of a lower housing  152  and an upper housing  154 . 
     Ring gear  130  may be fixed to one of lower housing  152  and upper housing  154 . 
     In the present embodiment, ring gear  130  is fixed to the inner surface of upper housing  154 . Upper housing  154  has a carrier shaft hole  151 , through which carrier shaft  160  penetrates. 
     When torque is transferred to ring gear  130 , gear housing  150  is rotated along with ring gear  130 . 
     In the present embodiment, gear housing  150  is connected to outer pulsator  94 . Gear housing  150  rotates outer pulsator  94 . 
     In order to transfer torque of gear housing  150  to outer pulsator  94 , upper housing  154  is provided with a housing holding protrusion  155 . 
     Outer pulsator  94  is coupled to housing holding protrusion  155 . Housing holding protrusion  155  may interfere with outer pulsator  94  and may transfer torque to outer pulsator  94  via interference therebetween. 
     In the present embodiment, housing holding protrusion  155  is configured to vertically protrude. Outer pulsator  94  is vertically coupled to housing holding protrusion  155  and is horizontally caught by housing holding protrusion  155 . 
     Outer pulsator  94  and housing holding protrusion  155  may be formed in various directions and shapes. 
     In addition, outer pulsator  94  and gear housing  150  may be coupled to each other via any of various methods. For example, outer pulsator  94  and gear housing  150  may be hook-coupled to each other. Outer pulsator  94  and gear housing  150  may be fastened and coupled to each other. 
     For rotation of sun gear  110 , planetary gears  120 , carrier  140  and gear housing  150 , in the present embodiment, bearings are arranged. 
     A first bearing  171  may be located between sun gear  110  and lower carrier body  142 . First bearing  171  may be located in lower sun gear recess  146 . 
     A second bearing  172  may be located between sun gear  110  and upper carrier body  144 . Second bearing  172  may be located in upper sun gear recess  147 . First bearing  171  and second bearing  172  minimize friction to enable the efficient rotation of sun gear  110 . 
     A third bearing  173  may be located between lower carrier body  142  and lower housing  152 . Third bearing  173  minimizes friction to enable the efficient rotation of lower carrier body  142  and gear housing  150 . 
     A fourth bearing  174  may be located between upper carrier body  144  and upper housing  154 . Fourth bearing  174  may be located between carrier shaft  160  and upper housing  154 . Fourth bearing  174  is inserted into and installed in upper housing  154 . Upper housing  154  is provided with a bearing recess  153 , into which fourth bearing  174  is inserted. In the present embodiment, bearing recess  153  and carrier shaft hole  151  are connected to each other. The diameter of bearing recess  153  is greater than the diameter of carrier shaft hole  151 . Fourth bearing  174  minimizes friction to enable the efficient rotation of upper carrier body  144  or carrier shaft  160 . 
     In the present embodiment, first bearing  171  is placed on carrier  140 . First bearing  171  is placed on lower carrier body  142 . 
     Second bearing  172  is installed to downwardly apply pressure to sun gear  110 . 
     Lower carrier body  142  and upper carrier body  144  apply pressure to sun gear  110  through first bearing  171  and second bearing  172 . 
     Sun gear  110  is fitted and installed between lower carrier body  142  and upper carrier body  144  and is rotatable only in the horizontal direction. 
     In the present embodiment, third bearing  173  is placed on lower housing  152 . In addition, carrier  140  is placed on third bearing  173 . 
     Fourth bearing  174  is fitted and installed between upper housing  154  and upper carrier body  144 . 
     When upper housing  154  and lower housing  152  are assembled with each other, fourth bearing  174  and third bearing  173  support gear housing  150 . 
     drive shaft  54  supports sun gear  110 . Sun gear  110  supports planetary gears  120  and carrier  140 . Carrier  140  supports gear housing  150 . Carrier  140  supports inner pulsator  92 . Gear housing  150  supports outer pulsator  94   
     Hereinafter, the operating process of the dual pulsator according to the present embodiment (i.e. the first embodiment or the second embodiment) will be described in more detail with reference to the accompanying drawings. 
     First, when power is applied to drive module  50  and motor  52  is operated, drive shaft  54  is rotated. When drive shaft  54  is rotated, sun gear  110  connected to drive shaft  54  is rotated. 
     Drive shaft  54  may be rotated clockwise or counterclockwise via operation of motor  52 . 
     For convenience of description, the direction in which drive shaft  54  is rotated is defined as a forward direction, and the rotation direction opposite to the forward direction is defined as a reverse direction. 
     Sun gear  110 , which is directly installed to drive shaft  54 , is rotated in the forward direction. 
     Because planetary gears  120  come into contact with the outer circumference of sun gear  110  and are engaged with sun gear  110 , planetary gears  120  are rotated in the direction opposite to the rotation direction of sun gear  110 . That is, planetary gears  120  are rotated in the reverse direction. 
     Here, carrier  140 , which connects planetary gears  120  to one another, is rotated in the forward direction opposite to the rotation direction of planetary gears  120 . That is, sun gear  110  and carrier  140  are rotated in the same direction. 
     Each planetary gear  120  rotates about planetary gear shaft  141  and rotates along the outer circumference of sun gear  110 . Planetary gear  120  is not fixed, but is free, thus receiving repulsive force when engaged with ring gear  130 . 
     Thus, ring gear  130  is rotated in the reverse direction opposite to the rotation direction of carrier  140 . 
     In this way, carrier  140  and ring gear  130  according to the present embodiment are rotated in opposite directions. 
     In the present embodiment, carrier  140  is coupled to inner pulsator  92  via carrier shaft  160 , and gear housing  150  is coupled to outer pulsator  94 . 
     As such, when sun gear  110  is rotated, inner pulsator and outer pulsator  94  may be rotated in opposite directions. 
     The present embodiment has a feature by which carrier  140  is in a free state rather than being constrained. Because carrier  140  is in the free state, the rotation speed of carrier  140  may vary depending on the load applied to inner pulsator  92  or outer pulsator  94 . 
     In the present embodiment, torque is input to only sun gear  110 , and all of planetary gears  120 , carrier  140  and ring gear  130  are in the free state. 
     Thus, the rotation speed of inner pulsator  92  or the rotation speed of outer pulsator  94  may vary depending on the load applied to inner pulsator  92  or outer pulsator  94 . 
     For example, the inner and outer pulsators  92  and  94  may be rotated at different speeds depending on whether a large load of laundry is located on inner pulsator  92  or outer pulsator  94 . In addition, the rotation speeds of the inner and outer pulsators  92  and  94  may vary depending on the load even when laundry is located on both inner pulsator  92  and outer pulsator  94 . 
     When inner pulsator  92  and outer pulsator  94  are rotated in opposite directions and the rotation speeds thereof vary as described above, the washing effect may be maximized. For example, an operation of twisting, rubbing, or squeezing laundry may be realized. In particular, because the speeds vary depending on the size of the laundry load, damage to the laundry may be reduced. 
     When the pulsator is operated at a high speed in the case of a large load of laundry as in the related art, the laundry may be damaged due to excess friction. In the washing machine according to the present embodiment, inner pulsator  92  or outer pulsator  94  may be rotated at a low speed under the condition of a high load, and may be rotated at a high speed under the condition of a low load. 
     The rotation speeds of inner pulsator  92  and outer pulsator  94  are described by the graph of  FIG. 6 . 
     The rotation speed of the inner pulsator W inner pulsator  is represented by the following Equation: 
     
       
         
           
             
               W 
               
                 Inner 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 pulsator 
               
             
             = 
             
               
                 
                   
                     w 
                     s 
                   
                   ⁢ 
                   
                     Z 
                     s 
                   
                 
                 - 
                 
                   
                     w 
                     
                       Outer 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       pulsator 
                     
                   
                   ⁢ 
                   
                     Z 
                     r 
                   
                 
               
               
                 
                   Z 
                   s 
                 
                 + 
                 
                   Z 
                   r 
                 
               
             
           
         
       
     
     where, W s : the rotation speed of the sun gear 
     W m : the rotation speed of the motor 
     W r : the rotation speed of the ring gear 
     W outer pulsator : the rotation speed of the outer pulsator 
     Z s : the number of teeth of the sun gear 
     Z r : the number of teeth of the ring gear 
     In the present embodiment, because sun gear  110  and drive shaft  54  are directly connected to each other, the rotation speed of motor  52  and the rotation speed of sun gear  100  are the same. 
     In the present embodiment, because gear housing  150  to which ring gear  130  is fixed and outer pulsator  94  are directly connected to each other, the rotation speed of ring gear  130  and rotation speed of outer pulsator  94  are the same. 
     In the present embodiment, the number of teeth of sun gear  110  is 110, the number of teeth of planetary gear  120  is 20, and the number of teeth of ring gear  130  is 80. 
     Analyzing the graph based on the above equation, the rotation speed of the inner pulsator W inner pulsator  is within the range from 0 to ⅓ W m  (the rotation speed of the motor), and the rotation speed of the outer pulsator W outer pulsator  is within the range from 0 to ½ W m  (the rotation speed of the motor). 
     In the present embodiment (i.e. the first embodiment or the second embodiment), the top-loading-type washing machine includes drum  40  in which vertically introduced laundry is loaded, drive module  50  for rotating drum  40  via drive shaft  54 , inner pulsator  92  placed in drum  40  and located on drive shaft  54  so as to be rotated upon receiving torque from drive module  50 , outer pulsator  94  placed in drum  40  so as to be rotated in the direction opposite to the rotation direction of inner pulsator  92  upon receiving torque from drive module  50 , and gearbox  100  located between drive module  50  and drum  40  and connected to drive shaft  54  so as to receive torque, gearbox  100  causing inner pulsator and outer pulsator  94  to be rotated in opposite directions. 
     Gearbox  100  includes sun gear  110  rotatably connected to drive shaft  54 , planetary gears  120  engaged with sun gear  110  and configured to rotate on their axes while rotating along the outer circumferential surface of sun gear  110 , ring gear  130  rotatably engaged with planetary gears  120 , carrier  140  for providing the rotation axis of each planetary gear  120  and connecting planetary gears  120  to one another, carrier  140  being rotated when planetary gears  120  are rotated along the outer circumferential surface of sun gear  110 , gear housing  150 , to which ring gear  130  is fixed, gear housing  150  being coupled to outer pulsator  140  to transfer torque, and carrier shaft  160  formed on carrier  140  and coupled to inner pulsator  92  so as to transfer torque. 
     Carrier shaft bore  161  is formed in carrier shaft  160  so as to communicate with the inside of gear box  100 . The top-loading-type washing machine further includes long-axis bolts  220  and  200 . Each of the long-axis bolts  220  and  200  is fastened at the lower end thereof to drive shaft  54  and is inserted into carrier shaft bore  161  so as to be rotated in carrier shaft bore  161 . 
     The coupling structure of inner pulsator  92  and drive shaft  54  according to the first embodiment will be described below with reference to  FIGS. 2A and 7A . The top-loading-type washing machine according to the first embodiment further includes a top bolt  210  for connecting the inner pulsator  92  and carrier shaft  160  to each other. Long-axis bolt  220  according to the first embodiment has an upper end inserted into carrier shaft bore  161 . 
     In the first embodiment, torque of carrier  140  is transferred to inner pulsator  92 . 
     Carrier shaft  160  is placed on carrier  140  and inner pulsator  92  and drive shaft  54  are assembled with each other via carrier shaft  160 . 
     In the first embodiment, top bolt  210  for assembling inner pulsator  92  and carrier shaft  160  with each other and long-axis bolt  220  for assembling carrier shaft  160  and drive shaft  54  with each other are installed. 
     Top bolt  210  is installed at the rotation center of inner pulsator  92 . Inner pulsator  92  has a bolt installation recess  98  in which top bolt  210  is installed. Top bolt  210  does not transfer torque to inner pulsator  92 . 
     Top bolt  210  serves to couple inner pulsator  92  to carrier shaft  160 . 
     Top bolt  210  includes a bolt body  212  and a bolt head  214  formed on the upper end of bolt body  212 . 
     Bolt body  212  penetrates inner pulsator  92  and is inserted into carrier shaft bore  161 . The lower end of bolt body  212  is fastened to carrier shaft  160 . 
     Bolt body  212  and carrier shaft  161  have screw-threads for fastening therebetween. 
     The screw-threads may be formed on only a portion of bolt body  212 . 
     The lower end of bolt body  212  is fastened to carrier shaft  160 . To this end, male screw-thread are formed on only a portion of the lower end of bolt body  212 . Female screw-threads are formed on the upper end of carrier shaft bore  161 . 
     The lower end of top bolt  210  may be fastened and coupled to the upper end of carrier shaft bore  161 , and the upper end of top bolt  210  may be rotated relative to inner pulsator  92 . 
     Top bolt  210  may have a tapered bolt portion  215 , which protrudes radially from bolt head  214 . Tapered bolt portion  215  is tapered downward. 
     A bolt support portion  217 , which corresponds to tapered bolt portion  215 , is located in bolt installation recess  98 . Tapered bolt portion  215  and bolt support portion  217  may have a hopper shape. 
     Bolt body  212  penetrates bolt support portion  217 . 
     Top bolt  210  is fastened to carrier shaft  160 , thereby limiting the upward movement of inner pulsator  92 . 
     Top bolt  210  is directly connected to carrier shaft  160 , and therefore is rotated at the same speed as carrier shaft  160 . Inner pulsator  92  is coupled to the outer circumference side of carrier shaft  160  so as to receive torque. As such, inner pulsator  92  is rotated at the same speed as carrier shaft  160 . 
     That is, although inner pulsator  92  may be rotated relative to top bolt  210  via the fastening structure of top bolt  210 , the relative rotation may not be realized because carrier shaft  160  and inner pulsator  92  are coupled to each other. 
     Inner pulsator  92  and carrier shaft  160  substantially operate integrally with each other. 
     However, inner pulsator  92  may perform relative rotation by a predetermined angle around bolt head  214  due to elasticity or deformation of the material of inner pulsator  92 . 
     Meanwhile, the top-loading-type washing machine may further include an inner cap  99 , which covers bolt installation recess  98  and prevents the introduction of wash water. Inner cap  99  covers the top of bolt installation recess  98 . Inner cap  99  is assembled with inner pulsator  92 . Inner cap  99  is rotated along with inner pulsator  92 . A sealing member  201  for preventing the introduction of wash water may further be installed inside inner cap  99 . 
     Top bolt  210  penetrates inner pulsator  92  and is fastened to carrier shaft  160 . Top bolt  210  is supported at the upper end thereof by inner pulsator  92  and the lower end of top bolt  210  is inserted into and fastened to carrier shaft bore  161 . Top bolt  210  includes bolt head  214  supported by inner pulsator  92 . Top bolt  210  includes bolt body  212 , which is inserted into carrier shaft bore  161  and is fastened to carrier shaft  160 . 
     Long-axis bolt  220  may be installed on carrier shaft  160 . 
     Long-axis bolt  220  is located in carrier shaft bore  161 . Long-axis bolt  220  is assembled with drive shaft  54 . 
     Long-axis bolt  220  includes a bolt head  224  and a bolt body  222 . 
     Bolt body  222  is provided with male screw-threads. Bolt body  222  is screwed to drive shaft  54 . For screwing, the upper end of drive shaft  54  is provided with female screw-threads. 
     Bolt head  224  is inserted in carrier shaft bore  161 . Bolt head  224  is not constrained by carrier shaft bore  161  or carrier shaft  160 . Bolt head  224  is vertically movable along carrier shaft bore  161 . Bolt head  224  is rotatable in carrier shaft bore  161 . 
     That is, bolt head  224  may be rotated relative to carrier shaft  160 . 
     In the first embodiment, an adaptor  230  is installed between bolt body  222  and drive shaft  54 . Adaptor  230  serves to compensate for a diameter difference. Unlike the first embodiment, when the male screw-threads of bolt body  222  and the female screw-threads of drive shaft  54  have the same diameter, bolt body  222  and drive shaft  54  may be directly fastened to each other. 
     The upper end of long-axis bolt  220  is inserted into carrier shaft bore  161 . Long-axis bolt  220  includes bolt head  224 , which is inserted into carrier shaft bore  161  and is movable along carrier shaft bore  161 . Long-axis bolt  220  includes bolt body  222  fastened to drive shaft  54 . 
     When drive shaft  54  is rotated, long-axis bolt  220  is rotated integrally with drive shaft  54  and is rotated relative to carrier shaft  160  differently from carrier shaft  160 . Long-axis bolt  220  is connected to drive shaft  54  so as to rotate at the same speed and direction as drive shaft  54 . The coupling structure of inner pulsator  92  and drive shaft  54  according to the second embodiment will be described with reference to  FIGS. 2B and 7B . Long-axis bolt  200  according to the second embodiment penetrates carrier shaft  160 , has an upper end supported by inner pulsator  92 , and is rotated relative to inner pulsator  92  and carrier shaft  160 . 
     In the second embodiment, torque of carrier  140  is transferred to inner pulsator  92 . 
     Carrier shaft  160  is placed on carrier  140 , and inner pulsator  92  and drive shaft  54  are assembled with each other via carrier shaft  160 . 
     In the second embodiment, long-axis bolt  200  for assembling inner pulsator  92  and drive shaft  54  with each other is used. 
     Long-axis bolt  200  is installed at the rotation center of inner pulsator  92 . Inner pulsator  92  has bolt installation recess  98  in which long-axis bolt  200  is installed. Long-axis bolt  200  does not transfer torque to inner pulsator  92 . 
     Long-axis bolt  200  serves to fasten inner pulsator  92  to drive shaft  54 . Torque is transferred to inner pulsator  92  via carrier shaft  160 . 
     Long-axis bolt  200  includes a bolt body  202  and a bolt head  204  formed on the upper end of bolt body  202 . 
     Bolt body  202  penetrates inner pulsator  92  and is inserted into carrier shaft bore  161 . The lower end of bolt body  202  is fastened to drive shaft  54 . 
     Bolt body  202  and drive shaft  54  are provided with screw-threads for fastening therebetween. 
     The screw-threads may be formed on only a portion of bolt body  202 . That is, bolt body  202  is not fastened to carrier shaft  160 , but fastened to drive shaft  54 . 
     To this end, male screw-threads may be formed on only a portion of bolt body  202 . The upper end of drive shaft  54  is provided with female screw-threads so that the lower end of bolt body  202  is inserted into and fastened to the upper end of drive shaft  54 . 
     As such, bolt body  202  and carrier shaft  160  may be rotated relative to each other. 
     Long-axis bolt  200  may have a tapered bolt portion  205 , which protrudes radially from bolt head  204 . Tapered bolt portion  205  is tapered downward. 
     A bolt support portion  206  is located in bolt installation recess  98  in order to support tapered bolt portion  205 . Long-axis bolt  200  is installed to penetrate bolt support portion  206 . The inner surface of bolt support portion  206  has a slope corresponding to tapered bolt portion  205 . 
     Bolt support portion  206  supports the bottom of bolt head  214 . 
     Tapered bolt portion  205  limits the upward movement of inner pulsator  92 . 
     A bolt bearing  208  may further be installed between bolt support portion  206  and inner pulsator  92 . Bolt bearing  208  reduces friction with long-axis bolt  200  when inner pulsator  92  is rotated. 
     When no bolt support portion  206  is installed, bolt bearing  208  may be installed between bolt head  204  and inner pulsator  92 . Tapered bolt portion  205  may be omitted. 
     Long-axis bolt  200  is directly connected to drive shaft  54 , and therefore is rotated at the same speed as drive shaft  54 . Inner pulsator  92  is coupled to carrier shaft  160 , and therefore is rotated at the same speed as carrier  140 . 
     Because the rotation speed of carrier  140  and the rotation speed of drive shaft  54  may be different, bolt bearing  208  may be installed to reduce friction. 
     The top-loading-type washing machine may further include inner cap  99 , which covers bolt installation recess  98  and prevents the introduction of wash water. Inner cap  99  covers the top of bolt installation recess  98 . Inner cap  99  is assembled with inner pulsator  92 . Inner cap  99  is rotated along with inner pulsator  92 . Sealing member  201  for preventing the introduction of wash water may be additionally installed inside inner cap  99 . 
     The upper end of long-axis bolt  200  penetrates inner pulsator  92 , and long-axis bolt  200  limits the upward movement of inner pulsator  92 . Bolt head  204  is supported by inner pulsator  92 . Bolt body  202  is fastened to drive shaft  54 . Bolt support portion  206  is located between inner pulsator  92  and bolt head  204  and supports bolt head  204 . Bolt head  204  has tapered bolt portion  205  protruding radially therefrom. Tapered bolt portion  205  is supported by bolt support portion  206 . Bolt bearing  208  is located between bolt support portion  206  and inner pulsator  92 . Inner pulsator  92  has bolt installation recess  98  in which long-axis bolt  200  is installed. The top-loading-type washing machine includes inner cap  99 , which covers bolt installation recess  98  and is coupled to inner pulsator  92 . 
     When drive shaft  54  is rotated, long-axis bolt  220  is rotated integrally with drive shaft  54  and is rotated relative to carrier shaft  160  and inner pulsator  92  differently from carrier shaft  160  and inner pulsator  92 . long-axis bolt  220  is connected to drive shaft  54  so as to rotate at the same speed and direction as drive shaft  54 . 
     The sealing of the carrier shaft according to the present embodiment (i.e. the first embodiment or the second embodiment) will be described with reference to  FIG. 8 . 
     A sealing member  250  for preventing the introduction of wash water may further be installed between carrier shaft  160  and gear housing  150 , which are rotated. 
     Sealing member  250  is installed in carrier shaft hole  151 . Sealing member  250  surrounds carrier shaft  160 , which penetrates carrier shaft hole  151 . 
     Sealing member  250  is located above fourth bearing  174 . 
     The entire sealing member  250  has a ring shape. 
     Sealing member  250  includes a sealing body  252 , which comes into close contact with gear housing  150  and is supported by gear housing  150 , and a tensional sealing portion  254 , which is connected to sealing body  252  and comes into close contact with carrier shaft  160 . 
     Sealing body  252  is located at an outer position, and tensional sealing portion  254  is located at an inner position. 
     Tensional sealing portion  254  may be elastically deformed relative to sealing body  252 . Tensional sealing portion  254  is bent downward from the upper end of sealing body  252 . 
     A tensional space  253  is defined between tensional sealing portion  254  and sealing body  252 . 
     A sealing arm  256  may protrude from tensional sealing portion  254  toward carrier shaft  160  and may be oriented to face upward. A plurality of sealing arms  256  may be arranged in the vertical direction. Sealing arms  256  have a ring shape. 
     As is apparent from the above description, a top-loading-type washing machine according to the present invention has an advantage of achieving excellent washing performance because an inner pulsator and an outer pulsator are rotated in opposite directions. 
     The top-loading-type washing machine according to the present invention has an advantage in that the rotation speeds of the inner pulsator and the outer pulsator are variable depending on the size of the laundry load. 
     The top-loading-type washing machine according to the present invention has an advantage of reducing power consumption because the rotation speeds of the inner pulsator and the outer pulsator are variable depending on the size of the laundry load. 
     The top-loading-type washing machine according to the present invention has an advantage of reducing damage to laundry because the rotation speeds of the inner pulsator and the outer pulsator are reduced under the condition of a high load. 
     The top-loading-type washing machine according to the present invention has an advantage of minimizing friction and interference due to relative rotation when the inner pulsator is rotated because a top bolt is used to rotate along with the inner pulsator and a long-axis bolt is used to rotate along with a drive shaft. 
     The top-loading-type washing machine according to the present invention has an advantage in that a carrier and the drive shaft, which are rotated at different speeds, are assembled with each other using only a top bolt and a long-axis bolt.