Top-loading type washing machine

A top-loading-type washing machine including a drum, a drive module for rotating the drum via a drive shaft, inner and outer pulsators placed in the drum so as to be rotated in opposite directions, and a gearbox connected to the drive shaft for rotating both the pulsators. The gearbox includes a sun gear rotatably connected to the drive shaft, planetary gears rotatably engaged with the sun gear, a ring gear rotatably engaged with the planetary gears, a carrier for connecting the planetary gears so as to be rotated along with the planetary gears, a gear housing to which the ring gear is fixed, the gear housing being coupled to the outer pulsator, and a carrier shaft coupled to the inner pulsator. The top-loading-type washing machine further includes a long-axis bolt fastened to the drive shaft and rotatably inserted into a carrier shaft bore of the carrier shaft.

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

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.

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 8are views illustrating common elements of the first embodiment and the second embodiment,FIGS. 2A and 7Aare views illustrating the configuration of the first embodiment, andFIGS. 2B and 7Bare 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 toFIG. 1, a washing machine according to the present embodiment (i.e., the first embodiment or the second embodiment) includes a casing10defining the external appearance of the washing machine, and a control module20installed on casing10.

Control module20includes, 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 tub30placed inside casing10for storing wash water therein, a drum40placed inside tub30for storing laundry to be washed, a drive module50placed on tub30for rotating drum40in order to wash the laundry, a water supply module60for supplying wash water to tub30, a water drain module70for discharging wash water stored in tub30, a suspension module80for reducing or absorbing vibrations generated in tub30, and a dual pulsator90placed in drum40so as to be rotated upon receiving drive power from drive module50.

Dual pulsator90is comprised of an inner pulsator92and an outer pulsator94. The axis centers of the respective pulsators92and94are located on the imaginary axis of a drive shaft of drive module50. The respective pulsators92and94are adapted to be rotated in opposite directions.

Casing10includes a main body12in which tub30and drum40are placed, a top cover14located on the top side of main body12, and a door formed in top cover14for opening or closing the inside of casing10.

Control module20includes, for example, manipulation buttons and a dial for receiving manipulation force from a user.

Control module20is 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 cover14.

Tub30is connected to water supply module60and stores wash water supplied from water supply module60.

Tub30may be connected to water drain module70, and water drain module70may discharge the wash water stored in tub30outward.

Drum40is placed inside tub30. Drum40is rotated upon receiving drive power from drive module50.

Drum40includes a drum body having a cylindrical shape, and a drum base coupled to the bottom side of the drum body.

A hub46is disposed on the drum base. Drive module50may selectively transfer drive power to hub46.

Drum40is configured to be rotated forward or in reverse relative to tub30.

In the present embodiment, water supply module60includes a water supply valve61and a water supply path62, which are located on top cover14.

In the present embodiment, water drain module70includes a water drain valve71connected to tub30, and a water drain path72connected to water drain valve71.

Suspension module80is connected to tub30, and reduces vibrations generated in tub30using at least one of elasticity or absorption.

In the present embodiment, suspension module80is located between casing10and tub30. Suspension module80supports the bottom of tub30and hangs from top cover14.

The structure of dual pulsator90according to the present embodiment (i.e. the first embodiment or the second embodiment) will be described with reference toFIGS. 2A to 8.

In the present embodiment, drive module50includes a motor52located on the bottom side of tub30, a drive shaft penetrating tub30and connected to drum40, and a gearbox100for transferring drive power of drive shaft54to dual pulsator90.

Drive shaft54is disposed to penetrate hub46.

Drive shaft54may be selectively connected to hub46of drum40. Thus, only drum40may be rotated by drive module50.

Drive shaft54may be selectively connected to gearbox100.

When drive shaft54and gearbox100are connected to each other, dual pulsator90may be rotated.

Dual pulsator90is located at the upper side of hub46.

Dual pulsator90includes inner pulsator92and outer pulsator94. Inner pulsator92is located at the inner side of outer pulsator94.

Inner pulsator92has a circular shape when viewed in a plan view.

Outer pulsator94has a ring shape when viewed in a plan view.

An installation hole95in which inner pulsator92is rotated is defined inside outer pulsator94.

Inner pulsator92and outer pulsator94may be rotated in different directions from each other.

In the present embodiment, dual pulsator90further includes a pulsator base96located at the lower side of inner pulsator92. Pulsator base96and outer pulsator94are defined as an outer assembly.

Inner pulsator92is located above outer pulsator94. Inner pulsator92is rotated above outer pulsator94.

Inner pulsator92may be provided with an upwardly protruding wash blade91. In the present embodiment, three wash blades91are arranged at an angular interval of 120 degrees when viewed in a plan view.

Outer pulsator94may also be provided with an upwardly protruding wash blade93. In the present embodiment, six wash blades93are equidistantly arranged when viewed in a plan view.

Inner pulsator92is located on the center of outer pulsator94when viewed in a plan view. Rotation centers of inner pulsator92and outer pulsator94are located on drive shaft54.

Installation hole95is defined inside outer pulsator94. An installation groove97is formed in the inner edge of outer pulsator94defining installation hole95. A portion of inner pulsator92is inserted into installation groove97.

Gearbox100is connected to motor52of drive module50and receives drive power. Drive shaft54of drive module50is also connected to gearbox100.

Gearbox100is connected to each of inner pulsator92and outer pulsator94. Gearbox100may be selectively connected to motor52.

Gearbox100may receive drive power of motor52and transfer the drive power to inner pulsator92and outer pulsator94.

Gearbox100may rotate inner pulsator92and outer pulsator94at different speeds depending on the size of the laundry load even if constant drive power is input from motor52.

Gearbox100includes a sun gear110rotatably connected to drive shaft54of motor52, a plurality of planetary gears120rotatably engaged with sun gear110, a ring gear130rotatably engaged with planetary gears120, a carrier140for connecting planetary gears120to one another, and a gear housing150to which ring gear130is fixed, sun gear110, planetary gears120and carrier140being placed inside gear housing150.

Sun gear110, planetary gears120, ring gear130, and carrier140are 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 gear110is rotated.

In the present embodiment, carrier140is operated in a non-constrained free state.

Sun gear110is coupled to drive shaft54. Sun gear110is provided on inner and outer sides thereof with gear teeth.

Sun gear110has a sun gear bore111vertically formed therein. The inner circumferential surface of sun gear110defining sun gear bore111is provided with inner teeth112. Outer teeth114are formed on the outer circumferential surface of sun gear110.

Drive shaft54is inserted into sun gear bore111. Drive shaft54is engaged with inner teeth112. Drive shaft54has a serrated shape.

Planetary gears120are arranged around sun gear110.

Planetary gears120may rotate on their axes while rotating along the circumference of sun gear110. To rotate on its axis, each planetary gear120has a planetary gear bore121vertically formed therein.

Planetary gear120may rotate about planetary gear bore121. In addition, planetary gear120may rotate along outer teeth114of sun gear110.

In the present embodiment, six planetary gears120are arranged. Each planetary gear120is engaged with outer teeth114of sun gear110. Sun gear110and planetary gears120are horizontally arranged.

Ring gear130is located at the outer side of planetary gears120.

In the present embodiment, ring gear130is fixed inside gear housing150.

Ring gear130has a ring shape. Ring gear130has teeth formed on the inner circumferential surface thereof. Ring gear130is engaged with all of planetary gears120at the same time.

Planetary gears120are located between ring gear130and sun gear110, and are simultaneously engaged with ring gear130and sun gear110.

Carrier140connects planetary gears120to one another. Planetary gears120may be rotated at the same speed by carrier140.

Carrier140includes a lower carrier body142, an upper carrier body144, and a carrier shaft160formed on upper carrier body144so as to penetrate gear housing150and be coupled to inner pulsator92.

Sun gear110and planetary gears120are located between upper carrier body144and lower carrier body142.

Lower carrier body142is located below planetary gears120.

Upper carrier body144is located above planetary gears120.

In the present embodiment, a planetary gear shaft141is formed on lower carrier body142. Planetary gear shaft141is inserted into planetary gear bore121. Planetary gear120rotates about planetary gear shaft141.

A plurality of planetary gear shafts141are arranged on lower carrier body142in a circumferential direction. Planetary gear shafts141are equidistantly arranged in the circumferential direction.

Sun gear110is also located above lower carrier body142. Sun gear110is rotated above lower carrier body142.

Lower carrier body142is provided with a lower sun gear recess146, into which sun gear110is inserted. Drive shaft54is also inserted through lower sun gear recess146. Drive shaft54, inserted through lower sun gear recess146, is coupled to sun gear110.

Upper carrier body144is located above lower carrier body142. Sun gear110supports upper carrier body144. Upper carrier body144and lower carrier body142are coupled to each other.

Upper carrier body144has an upper sun gear recess147formed in the lower surface thereof, into which a portion of sun gear110is inserted. Upper carrier body144further has a planetary gear shaft recess148formed in the lower surface thereof, into which planetary gear shaft141is inserted.

Upper carrier body144and lower carrier body142are assembled with each other and operate integrally with each other.

Carrier shaft160protrudes upward from upper carrier body144. Inner pulsator92is rotatably connected to carrier shaft160.

Carrier shaft160has a carrier shaft bore161formed therein. Carrier shaft bore161is formed in the center of carrier shaft160.

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 shafts141and carrier shaft160are formed on the single carrier body.

Gear housing150is comprised of a lower housing152and an upper housing154.

Ring gear130may be fixed to one of lower housing152and upper housing154.

In the present embodiment, ring gear130is fixed to the inner surface of upper housing154. Upper housing154has a carrier shaft hole151, through which carrier shaft160penetrates.

When torque is transferred to ring gear130, gear housing150is rotated along with ring gear130.

In the present embodiment, gear housing150is connected to outer pulsator94. Gear housing150rotates outer pulsator94.

In order to transfer torque of gear housing150to outer pulsator94, upper housing154is provided with a housing holding protrusion155.

Outer pulsator94is coupled to housing holding protrusion155. Housing holding protrusion155may interfere with outer pulsator94and may transfer torque to outer pulsator94via interference therebetween.

In the present embodiment, housing holding protrusion155is configured to vertically protrude. Outer pulsator94is vertically coupled to housing holding protrusion155and is horizontally caught by housing holding protrusion155.

Outer pulsator94and housing holding protrusion155may be formed in various directions and shapes.

In addition, outer pulsator94and gear housing150may be coupled to each other via any of various methods. For example, outer pulsator94and gear housing150may be hook-coupled to each other. Outer pulsator94and gear housing150may be fastened and coupled to each other.

For rotation of sun gear110, planetary gears120, carrier140and gear housing150, in the present embodiment, bearings are arranged.

A first bearing171may be located between sun gear110and lower carrier body142. First bearing171may be located in lower sun gear recess146.

A second bearing172may be located between sun gear110and upper carrier body144. Second bearing172may be located in upper sun gear recess147. First bearing171and second bearing172minimize friction to enable the efficient rotation of sun gear110.

A third bearing173may be located between lower carrier body142and lower housing152. Third bearing173minimizes friction to enable the efficient rotation of lower carrier body142and gear housing150.

A fourth bearing174may be located between upper carrier body144and upper housing154. Fourth bearing174may be located between carrier shaft160and upper housing154. Fourth bearing174is inserted into and installed in upper housing154. Upper housing154is provided with a bearing recess153, into which fourth bearing174is inserted. In the present embodiment, bearing recess153and carrier shaft hole151are connected to each other. The diameter of bearing recess153is greater than the diameter of carrier shaft hole151. Fourth bearing174minimizes friction to enable the efficient rotation of upper carrier body144or carrier shaft160.

In the present embodiment, first bearing171is placed on carrier140. First bearing171is placed on lower carrier body142.

Second bearing172is installed to downwardly apply pressure to sun gear110.

Lower carrier body142and upper carrier body144apply pressure to sun gear110through first bearing171and second bearing172.

Sun gear110is fitted and installed between lower carrier body142and upper carrier body144and is rotatable only in the horizontal direction.

In the present embodiment, third bearing173is placed on lower housing152. In addition, carrier140is placed on third bearing173.

Fourth bearing174is fitted and installed between upper housing154and upper carrier body144.

When upper housing154and lower housing152are assembled with each other, fourth bearing174and third bearing173support gear housing150.

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 module50and motor52is operated, drive shaft54is rotated. When drive shaft54is rotated, sun gear110connected to drive shaft54is rotated.

Drive shaft54may be rotated clockwise or counterclockwise via operation of motor52.

For convenience of description, the direction in which drive shaft54is rotated is defined as a forward direction, and the rotation direction opposite to the forward direction is defined as a reverse direction.

Sun gear110, which is directly installed to drive shaft54, is rotated in the forward direction.

Because planetary gears120come into contact with the outer circumference of sun gear110and are engaged with sun gear110, planetary gears120are rotated in the direction opposite to the rotation direction of sun gear110. That is, planetary gears120are rotated in the reverse direction.

Here, carrier140, which connects planetary gears120to one another, is rotated in the forward direction opposite to the rotation direction of planetary gears120. That is, sun gear110and carrier140are rotated in the same direction.

Each planetary gear120rotates about planetary gear shaft141and rotates along the outer circumference of sun gear110. Planetary gear120is not fixed, but is free, thus receiving repulsive force when engaged with ring gear130.

Thus, ring gear130is rotated in the reverse direction opposite to the rotation direction of carrier140.

In this way, carrier140and ring gear130according to the present embodiment are rotated in opposite directions.

In the present embodiment, carrier140is coupled to inner pulsator92via carrier shaft160, and gear housing150is coupled to outer pulsator94.

As such, when sun gear110is rotated, inner pulsator and outer pulsator94may be rotated in opposite directions.

The present embodiment has a feature by which carrier140is in a free state rather than being constrained. Because carrier140is in the free state, the rotation speed of carrier140may vary depending on the load applied to inner pulsator92or outer pulsator94.

In the present embodiment, torque is input to only sun gear110, and all of planetary gears120, carrier140and ring gear130are in the free state.

Thus, the rotation speed of inner pulsator92or the rotation speed of outer pulsator94may vary depending on the load applied to inner pulsator92or outer pulsator94.

For example, the inner and outer pulsators92and94may be rotated at different speeds depending on whether a large load of laundry is located on inner pulsator92or outer pulsator94. In addition, the rotation speeds of the inner and outer pulsators92and94may vary depending on the load even when laundry is located on both inner pulsator92and outer pulsator94.

When inner pulsator92and outer pulsator94are 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 pulsator92or outer pulsator94may 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 pulsator92and outer pulsator94are described by the graph ofFIG. 6.

The rotation speed of the inner pulsator Winner pulsatoris represented by the following Equation:

where, Ws: the rotation speed of the sun gear

Wm: the rotation speed of the motor

Wr: the rotation speed of the ring gear

Wouter pulsator: the rotation speed of the outer pulsator

Zs: the number of teeth of the sun gear

Zr: the number of teeth of the ring gear

In the present embodiment, because sun gear110and drive shaft54are directly connected to each other, the rotation speed of motor52and the rotation speed of sun gear100are the same.

In the present embodiment, because gear housing150to which ring gear130is fixed and outer pulsator94are directly connected to each other, the rotation speed of ring gear130and rotation speed of outer pulsator94are the same.

In the present embodiment, the number of teeth of sun gear110is 110, the number of teeth of planetary gear120is 20, and the number of teeth of ring gear130is 80.

Analyzing the graph based on the above equation, the rotation speed of the inner pulsator Winner pulsatoris within the range from 0 to ⅓ Wm(the rotation speed of the motor), and the rotation speed of the outer pulsator Wouter pulsatoris within the range from 0 to ½ Wm(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 drum40in which vertically introduced laundry is loaded, drive module50for rotating drum40via drive shaft54, inner pulsator92placed in drum40and located on drive shaft54so as to be rotated upon receiving torque from drive module50, outer pulsator94placed in drum40so as to be rotated in the direction opposite to the rotation direction of inner pulsator92upon receiving torque from drive module50, and gearbox100located between drive module50and drum40and connected to drive shaft54so as to receive torque, gearbox100causing inner pulsator and outer pulsator94to be rotated in opposite directions.

Gearbox100includes sun gear110rotatably connected to drive shaft54, planetary gears120engaged with sun gear110and configured to rotate on their axes while rotating along the outer circumferential surface of sun gear110, ring gear130rotatably engaged with planetary gears120, carrier140for providing the rotation axis of each planetary gear120and connecting planetary gears120to one another, carrier140being rotated when planetary gears120are rotated along the outer circumferential surface of sun gear110, gear housing150, to which ring gear130is fixed, gear housing150being coupled to outer pulsator140to transfer torque, and carrier shaft160formed on carrier140and coupled to inner pulsator92so as to transfer torque.

Carrier shaft bore161is formed in carrier shaft160so as to communicate with the inside of gear box100. The top-loading-type washing machine further includes long-axis bolts220and200. Each of the long-axis bolts220and200is fastened at the lower end thereof to drive shaft54and is inserted into carrier shaft bore161so as to be rotated in carrier shaft bore161.

The coupling structure of inner pulsator92and drive shaft54according to the first embodiment will be described below with reference toFIGS. 2A and 7A. The top-loading-type washing machine according to the first embodiment further includes a top bolt210for connecting the inner pulsator92and carrier shaft160to each other. Long-axis bolt220according to the first embodiment has an upper end inserted into carrier shaft bore161.

In the first embodiment, torque of carrier140is transferred to inner pulsator92.

Carrier shaft160is placed on carrier140and inner pulsator92and drive shaft54are assembled with each other via carrier shaft160.

In the first embodiment, top bolt210for assembling inner pulsator92and carrier shaft160with each other and long-axis bolt220for assembling carrier shaft160and drive shaft54with each other are installed.

Top bolt210is installed at the rotation center of inner pulsator92. Inner pulsator92has a bolt installation recess98in which top bolt210is installed. Top bolt210does not transfer torque to inner pulsator92.

Top bolt210serves to couple inner pulsator92to carrier shaft160.

Top bolt210includes a bolt body212and a bolt head214formed on the upper end of bolt body212.

Bolt body212penetrates inner pulsator92and is inserted into carrier shaft bore161. The lower end of bolt body212is fastened to carrier shaft160.

The screw-threads may be formed on only a portion of bolt body212.

The lower end of bolt body212is fastened to carrier shaft160. To this end, male screw-thread are formed on only a portion of the lower end of bolt body212. Female screw-threads are formed on the upper end of carrier shaft bore161.

The lower end of top bolt210may be fastened and coupled to the upper end of carrier shaft bore161, and the upper end of top bolt210may be rotated relative to inner pulsator92.

Top bolt210may have a tapered bolt portion215, which protrudes radially from bolt head214. Tapered bolt portion215is tapered downward.

A bolt support portion217, which corresponds to tapered bolt portion215, is located in bolt installation recess98. Tapered bolt portion215and bolt support portion217may have a hopper shape.

Top bolt210is fastened to carrier shaft160, thereby limiting the upward movement of inner pulsator92.

Top bolt210is directly connected to carrier shaft160, and therefore is rotated at the same speed as carrier shaft160. Inner pulsator92is coupled to the outer circumference side of carrier shaft160so as to receive torque. As such, inner pulsator92is rotated at the same speed as carrier shaft160.

That is, although inner pulsator92may be rotated relative to top bolt210via the fastening structure of top bolt210, the relative rotation may not be realized because carrier shaft160and inner pulsator92are coupled to each other.

Inner pulsator92and carrier shaft160substantially operate integrally with each other.

However, inner pulsator92may perform relative rotation by a predetermined angle around bolt head214due to elasticity or deformation of the material of inner pulsator92.

Meanwhile, the top-loading-type washing machine may further include an inner cap99, which covers bolt installation recess98and prevents the introduction of wash water. Inner cap99covers the top of bolt installation recess98. Inner cap99is assembled with inner pulsator92. Inner cap99is rotated along with inner pulsator92. A sealing member201for preventing the introduction of wash water may further be installed inside inner cap99.

Top bolt210penetrates inner pulsator92and is fastened to carrier shaft160. Top bolt210is supported at the upper end thereof by inner pulsator92and the lower end of top bolt210is inserted into and fastened to carrier shaft bore161. Top bolt210includes bolt head214supported by inner pulsator92. Top bolt210includes bolt body212, which is inserted into carrier shaft bore161and is fastened to carrier shaft160.

Long-axis bolt220may be installed on carrier shaft160.

Bolt body222is provided with male screw-threads. Bolt body222is screwed to drive shaft54. For screwing, the upper end of drive shaft54is provided with female screw-threads.

Bolt head224is inserted in carrier shaft bore161. Bolt head224is not constrained by carrier shaft bore161or carrier shaft160. Bolt head224is vertically movable along carrier shaft bore161. Bolt head224is rotatable in carrier shaft bore161.

That is, bolt head224may be rotated relative to carrier shaft160.

In the first embodiment, an adaptor230is installed between bolt body222and drive shaft54. Adaptor230serves to compensate for a diameter difference. Unlike the first embodiment, when the male screw-threads of bolt body222and the female screw-threads of drive shaft54have the same diameter, bolt body222and drive shaft54may be directly fastened to each other.

The upper end of long-axis bolt220is inserted into carrier shaft bore161. Long-axis bolt220includes bolt head224, which is inserted into carrier shaft bore161and is movable along carrier shaft bore161. Long-axis bolt220includes bolt body222fastened to drive shaft54.

When drive shaft54is rotated, long-axis bolt220is rotated integrally with drive shaft54and is rotated relative to carrier shaft160differently from carrier shaft160. Long-axis bolt220is connected to drive shaft54so as to rotate at the same speed and direction as drive shaft54. The coupling structure of inner pulsator92and drive shaft54according to the second embodiment will be described with reference toFIGS. 2B and 7B. Long-axis bolt200according to the second embodiment penetrates carrier shaft160, has an upper end supported by inner pulsator92, and is rotated relative to inner pulsator92and carrier shaft160.

In the second embodiment, torque of carrier140is transferred to inner pulsator92.

Carrier shaft160is placed on carrier140, and inner pulsator92and drive shaft54are assembled with each other via carrier shaft160.

In the second embodiment, long-axis bolt200for assembling inner pulsator92and drive shaft54with each other is used.

Long-axis bolt200is installed at the rotation center of inner pulsator92. Inner pulsator92has bolt installation recess98in which long-axis bolt200is installed. Long-axis bolt200does not transfer torque to inner pulsator92.

Long-axis bolt200serves to fasten inner pulsator92to drive shaft54. Torque is transferred to inner pulsator92via carrier shaft160.

Long-axis bolt200includes a bolt body202and a bolt head204formed on the upper end of bolt body202.

Bolt body202penetrates inner pulsator92and is inserted into carrier shaft bore161. The lower end of bolt body202is fastened to drive shaft54.

Bolt body202and drive shaft54are provided with screw-threads for fastening therebetween.

The screw-threads may be formed on only a portion of bolt body202. That is, bolt body202is not fastened to carrier shaft160, but fastened to drive shaft54.

To this end, male screw-threads may be formed on only a portion of bolt body202. The upper end of drive shaft54is provided with female screw-threads so that the lower end of bolt body202is inserted into and fastened to the upper end of drive shaft54.

As such, bolt body202and carrier shaft160may be rotated relative to each other.

A bolt support portion206is located in bolt installation recess98in order to support tapered bolt portion205. Long-axis bolt200is installed to penetrate bolt support portion206. The inner surface of bolt support portion206has a slope corresponding to tapered bolt portion205.

Bolt support portion206supports the bottom of bolt head214.

Tapered bolt portion205limits the upward movement of inner pulsator92.

A bolt bearing208may further be installed between bolt support portion206and inner pulsator92. Bolt bearing208reduces friction with long-axis bolt200when inner pulsator92is rotated.

When no bolt support portion206is installed, bolt bearing208may be installed between bolt head204and inner pulsator92. Tapered bolt portion205may be omitted.

Long-axis bolt200is directly connected to drive shaft54, and therefore is rotated at the same speed as drive shaft54. Inner pulsator92is coupled to carrier shaft160, and therefore is rotated at the same speed as carrier140.

Because the rotation speed of carrier140and the rotation speed of drive shaft54may be different, bolt bearing208may be installed to reduce friction.

The top-loading-type washing machine may further include inner cap99, which covers bolt installation recess98and prevents the introduction of wash water. Inner cap99covers the top of bolt installation recess98. Inner cap99is assembled with inner pulsator92. Inner cap99is rotated along with inner pulsator92. Sealing member201for preventing the introduction of wash water may be additionally installed inside inner cap99.

The upper end of long-axis bolt200penetrates inner pulsator92, and long-axis bolt200limits the upward movement of inner pulsator92. Bolt head204is supported by inner pulsator92. Bolt body202is fastened to drive shaft54. Bolt support portion206is located between inner pulsator92and bolt head204and supports bolt head204. Bolt head204has tapered bolt portion205protruding radially therefrom. Tapered bolt portion205is supported by bolt support portion206. Bolt bearing208is located between bolt support portion206and inner pulsator92. Inner pulsator92has bolt installation recess98in which long-axis bolt200is installed. The top-loading-type washing machine includes inner cap99, which covers bolt installation recess98and is coupled to inner pulsator92.

When drive shaft54is rotated, long-axis bolt220is rotated integrally with drive shaft54and is rotated relative to carrier shaft160and inner pulsator92differently from carrier shaft160and inner pulsator92. long-axis bolt220is connected to drive shaft54so as to rotate at the same speed and direction as drive shaft54.

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 toFIG. 8.

A sealing member250for preventing the introduction of wash water may further be installed between carrier shaft160and gear housing150, which are rotated.

Sealing member250is installed in carrier shaft hole151. Sealing member250surrounds carrier shaft160, which penetrates carrier shaft hole151.

Sealing member250is located above fourth bearing174.

The entire sealing member250has a ring shape.

Sealing member250includes a sealing body252, which comes into close contact with gear housing150and is supported by gear housing150, and a tensional sealing portion254, which is connected to sealing body252and comes into close contact with carrier shaft160.

Sealing body252is located at an outer position, and tensional sealing portion254is located at an inner position.

Tensional sealing portion254may be elastically deformed relative to sealing body252. Tensional sealing portion254is bent downward from the upper end of sealing body252.

A sealing arm256may protrude from tensional sealing portion254toward carrier shaft160and may be oriented to face upward. A plurality of sealing arms256may be arranged in the vertical direction. Sealing arms256have 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.