Tub for washing machine and washing machine having the same

A tub of a washing machine includes: a first case and a second case welded to each other; a first coupling surface formed along a circumference of the first case facing the second case; a second coupling surface formed along a circumference of the second case facing the first case and bonded to the first coupling surface; and a coupling protrusion that protrudes along the first coupling surface and includes a protruding end portion welded to the second coupling surface. The coupling protrusion includes: a main coupling protrusion protruding along the first coupling surface; and an auxiliary coupling protrusion protruding along the first coupling surface and outwardly spaced apart from the main coupling protrusion. Further, an opening for communicating a space between the auxiliary coupling protrusion and the main coupling protrusion to an outside of the tub is defined in a bottom of the tub.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority to Korean Patent Application No. 10-2018-0140072, filed on Nov. 14, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present disclosure relates to a tub for a washing machine and a washing machine having the same.

Discussion of the Related Art

In general, a washing machine is a home appliance for removing contaminants on clothes, bedding, or the like (hereinafter referred to as laundry) through processes such as washing, rinsing, dehydrating, drying, and the like, using water, detergent, a mechanical action, and the like.

Such washing machine may include a cabinet forming an outer shape of the washing machine, a tub installed inside the cabinet, a drum rotatably installed inside the tub and having a plurality of through-holes through which washing water or foam flows in and out, and a motor installed in the tub to rotate the drum. A rotation shaft of the motor may pass through one side of the tub to be connected to the drum.

The tub may define a washing space therein for receiving the drum, and may be opened toward an entrance for inserting and removing the laundry of the washing machine to define a passage through which the laundry is introduced into the drum.

When the washing machine is operated for washing the laundry, washing water for the washing is supplied into the tub. When the washing water is sufficiently filled in the tub, the drum is rotated by the motor. When the drum is rotated, the washing water inside the tub flows into and flows out of the drum through the plurality of through-holes defined in the drum, and the washing of the laundry received inside the drum is performed.

When the washing is completed, a drain pump disposed in the washing machine is operated, thereby discharging the washing water inside the tub.

In one example, an outer shape of the tub may be formed by a combination of a plurality of divided components. That is, the tub may be produced in a state in which the drum is received therein by the combination of the plurality of divided components. Each of the divided plurality of components of the tub may form a portion of the washing space of the tub.

For example, the tub may be formed in a substantially cylindrical shape. Further, the tub may include a first case for forming a half of the cylindrical shape and a second case to form the other half.

Conventionally, a coupling structure in which a gasket for sealing is provided on a contact face of the first case and the second case, and the first case and the second case are coupled with each other by a fastening member such as a bolt has been applied.

Korean Patent Application Publication No. 10-2006-0089786, which is a prior document, discloses a structure in which an outer shape of a tub 58 of a washing machine is formed by a combination of a tub cover 90 and a tub main body 92.

According to the prior document, the tub cover 90 forms a front portion of the tub 58 and the tub main body 92 forms a rear portion of the tub 58. Holes are defined in the tub cover 90 and the tub main body 92 along outer circumferences thereof, and fastening members 94 are coupled into the holes, thereby connecting the tub cover 90 and the tub main body 92 with each other.

However, when the first case and the second case, which form the tub, are coupled to each other by the fastening member as in the prior art, after the gasket is disposed between the first case and the second case, the fastening members must be fastened to the plurality of holes defined along the outer circumferences of the first case and the second case.

Therefore, work man-hour for assembly of the tub is increased to cause increase of production time of the washing machine.

In addition, due to the increase in the number of components such as the gaskets and the fastening members, misassembly of the tub may occur easily, resulting in increased component costs.

In addition, when a fastening force of the fastening member is lowered or the gasket is aged, leakage of the washing water between the first case and the second case may occur.

SUMMARY OF THE DISCLOSURE

The present embodiment provides a tub of a washing machine and a washing machine including the same in which an outer appearance of the tub of the washing machine may be formed by coupling of a first case and a second case, and the first case and the second case may be easily coupled to each other by a welding process.

The present embodiment provides a tub of a washing machine and a washing machine including the same in which a first case and a second case may be stably welded to each other by a welding process to prevent leakage of water.

The present embodiment provides a tub of a washing machine and a washing machine including the same in which flash generated during welding of a first case and a second case is prevented from flowing into the tub.

The present embodiment provides a tub of a washing machine and a washing machine including the same in which a coupling protrusion for welding of a first case and a second case includes a main coupling protrusion and an auxiliary coupling protrusion outward of the main coupling protrusion, and washing water leaked into a space between the main coupling protrusion and the auxiliary coupling protrusion is capable of being discharged to outside.

In a first aspect of the present disclosure, there is provided a tub for a washing machine, wherein the tub has a washing space defined therein and filled with washing water, wherein a drum for receiving laundry therein is rotatably disposed in the washing space. The tub includes: a first case and a second case welded to be coupled to each other to form the washing space and an outer appearance of the tub; a first coupling surface formed along a circumference of the first case facing the second case; a second coupling surface formed along a circumference of the second case facing the first case and bonded to the first coupling surface; and a coupling protrusion protruding along the first coupling surface to encircle the washing space, wherein a protruding end portion of the coupling protrusion is welded to the second coupling surface, wherein the coupling protrusion includes: a main coupling protrusion protruding along the first coupling surface; and an auxiliary coupling protrusion protruding along the first coupling surface and outwardly spaced apart from the main coupling protrusion, wherein an opening for communicating a space between the auxiliary coupling protrusion and the main coupling protrusion to an outside of the tub is defined in a bottom of the tub.

In one implementation, the opening may be defined at a position vertically lower than a height corresponding to a limiting level (H) of the washing water filled in the washing space.

In one implementation, the opening may be defined in the first coupling surface positioned between the main coupling protrusion and the auxiliary coupling protrusion at the bottom of the tub.

In one implementation, the opening may be defined in the second coupling surface positioned between the main coupling protrusion and the auxiliary coupling protrusion at the bottom of the tub.

In one implementation, a portion of the auxiliary coupling protrusion located at the bottom of the tub may be cut to define the opening.

In one implementation, a water collecting portion recessed downward for collecting the washing water supplied into the tub may be formed at the bottom of the tub, and a bottom face of the water collecting portion may be formed in a planar shape.

In one implementation, the first coupling surface positioned below the water collecting portion may have a lower-side straight portion formed thereon, the lower-side straight portion being configured to extend in a widthwise direction of the water collecting portion which is perpendicular to an axial direction of the tub, and the main coupling protrusion and the auxiliary coupling protrusion may be formed on the lower-side straight portion in a straight-line shape in the widthwise direction of the water collecting portion.

In one implementation, the opening may be defined at a central position of the auxiliary coupling protrusion formed on the lower-side straight portion.

In one implementation, the opening may be defined at a position biased in the widthwise direction of the water collection portion from a central position of the auxiliary coupling protrusion formed on the lower-side straight portion.

In one implementation, the opening is defined in at least one of left and right ends of the auxiliary coupling protrusions formed on the lower-side straight portion.

In one implementation, the coupling protrusion may include a plurality of connection ribs for connecting the main coupling protrusion and the auxiliary coupling protrusion in the space between the main coupling protrusion and the auxiliary coupling protrusion, wherein the plurality of connection ribs may be spaced apart from each other along the space between the main coupling protrusion and the auxiliary coupling protrusion.

In one implementation, the connection ribs may be formed at a height less than a height of the coupling protrusion in a state where the welding is completed.

In one implementation, the auxiliary coupling protrusion may have a radial thickness smaller than a radial thickness of the main coupling protrusion.

In one implementation, one of the first case and the second case forms a front portion of the tub and the other forms a rear portion of the tub.

In one implementation, the first coupling surface may extend outward of the circumference of the first case, and the second coupling surface may extend outward of the circumference of the second case.

In one implementation, the tub may further include a constraining protrusion protruding along the second coupling surface, the constraining protrusion being configured to constrain flash generated during the welding of the coupling protrusion in a space between the first coupling surface and the second coupling surface, and the constraining protrusion may be formed in at least one of a region of the second coupling surface located inward than the main coupling protrusion and a region of the second coupling surface located outward than the auxiliary coupling protrusion.

In one implementation, the constraining protrusion may be only formed in a region of the second coupling surface located inward than the main coupling protrusion.

In one implementation, the constraining protrusion may be located inwardly of the main coupling protrusion and may be spaced apart from the coupling protrusion.

In one implementation, the tub may further include guide protrusions formed at both sides of the second coupling surface, which face each other with respect to an internal space of the second case to guide the coupling protrusion towards the second coupling surface defined outside the constraining protrusion, and wherein the guide protrusion may have a slanted face declined outwardly.

In a first aspect of the present disclosure, there is provided a washing machine including: a cabinet having a space defined therein; a tub disposed in the cabinet to define a washing space filled with washing water; and a drum rotatably disposed inside the tub for receiving laundry therein, wherein the tub includes: a first case and a second case welded to be coupled to each other to form the washing space and an outer appearance of the tub; a first coupling surface formed along a circumference of the first case facing the second case; a second coupling surface formed along a circumference of the second case facing the first case and bonded to the first coupling surface; and a coupling protrusion protruding along the first coupling surface to encircle the washing space, wherein a protruding end portion of the coupling protrusion is welded to the second coupling surface, wherein the coupling protrusion includes: a main coupling protrusion protruding along the first coupling surface; and an auxiliary coupling protrusion protruding along the first coupling surface and outwardly spaced apart from the main coupling protrusion, wherein an opening for communicating a space between the auxiliary coupling protrusion and the main coupling protrusion to an outside of the tub is defined in a bottom of the tub.

In one implementation, the opening may be defined at a position vertically lower than a height corresponding to a limiting level (H) of the washing water filled in the washing space.

In one implementation, the opening may be defined in the first coupling surface positioned between the main coupling protrusion and the auxiliary coupling protrusion at the bottom of the tub.

In one implementation, the opening may be defined in the second coupling surface positioned between the main coupling protrusion and the auxiliary coupling protrusion at the bottom of the tub.

In one implementation, a portion of the auxiliary coupling portion located at the bottom of the tub may be cut to define the opening.

In one implementation, a water collecting portion recessed downward for collecting the washing water supplied into the tub may be formed at the bottom of the tub, and a bottom face of the water collecting portion may be formed in a planar shape.

In one implementation, the first coupling surface positioned below the water collecting portion may have a lower-side straight portion formed thereon, the lower-side straight portion being configure to extend in a widthwise direction of the water collecting portion which is perpendicular to an axial direction of the tub, and the main coupling protrusion and the auxiliary coupling protrusion may be formed on the lower-side straight portion in a straight-line shape in the widthwise direction of the water collecting portion.

In one implementation, the opening may be defined at a central position of the auxiliary coupling protrusion formed on the lower-side straight portion.

In one implementation, the opening may be defined at a position biased in the widthwise direction of the water collecting portion from a central position of the auxiliary coupling protrusion formed on the lower-side straight portion.

In one implementation, the opening is defined in at least one of left and right ends of the auxiliary coupling protrusions formed on the lower-side straight portion.

In one implementation, the coupling protrusion may include a plurality of connection ribs for connecting the main coupling protrusion and the auxiliary coupling protrusion in the space between the main coupling protrusion and the auxiliary coupling protrusion, wherein the plurality of connection ribs may be spaced apart from each other along the space between the main coupling protrusion and the auxiliary coupling protrusion, and wherein the plurality of connection ribs may have a height less than a height of the coupling protrusion in a state where the welding is completed.

In one implementation, the auxiliary coupling protrusion may be formed to have a radial thickness less than a radial thickness of the main coupling protrusion.

In one implementation, one of the first case and the second case may form a front portion of the tub and the other may form a rear portion of the tub.

In one implementation, the first coupling surface may extend outward of the circumference of the first case, and the second coupling surface may extend outward of the circumference of the second case.

In one implementation, the tub may further include a constraining protrusion protruding along the second coupling surface, the constraining protrusion being configured to constrain flash generated during the welding of the coupling protrusion in a space between the first coupling surface and the second coupling surface, and the constraining protrusion may be formed in at least one of a region of the second coupling surface located inward than the main coupling protrusion and a region of the second coupling surface located outward than the auxiliary coupling protrusion.

In one implementation, the tub may further include guide protrusions formed at both sides of the second coupling surface, which face each other with respect to an internal space of the second case to guide the coupling protrusion towards the second coupling surface define outside the constraining protrusion, and the guide protrusion may have a slanted face declined outwardly.

Further, the washing machine may further include: a base forming a bottom surface of the cabinet; a leakage detecting sensor disposed on the base for detecting leakage when the washing water is in contact therewith; an output device disposed on the cabinet for outputting information; and a controller that receives a leakage signal from the leakage detecting sensor; and outputs an alarm through the output device when the leakage occurs.

In one implementation, the leakage detecting sensor may be provided on the bottom surface of the base, and the bottom face of the base may be inclined downwardly toward the leakage detecting sensor.

In one implementation, the washing machine may further include a guide member extending from the opening toward the leakage detecting sensor, wherein the guide member guides the washing water discharged through the opening to the leakage detecting sensor.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that when components in the drawings are designated by reference numerals, the same components have the same reference numerals as far as possible even though the components are illustrated in different drawings. Further, in description of embodiments of the present disclosure, when it is determined that detailed descriptions of well-known configurations or functions disturb understanding of the embodiments of the present disclosure, the detailed descriptions will be omitted.

Also, in the description of the embodiments of the present disclosure, the terms such as first, second, A, B, (a) and (b) may be used. Each of the terms is merely used to distinguish the corresponding component from other components, and does not delimit an essence, an order or a sequence of the corresponding component. It should be understood that when one component is “connected”, “coupled” or “joined” to another component, the former may be directly connected or jointed to the latter or may be “connected”, coupled” or “joined” to the latter with a third component interposed therebetween.

FIG. 1is a cross-sectional view illustrating an internal configuration of a washing machine according to an embodiment of the present disclosure. Further,FIG. 2is a perspective view of a base fan according to an embodiment of the present disclosure. Further,FIG. 3is a view illustrating a state in which a tub is disassembled according to an embodiment of the present disclosure.

A tub100according to an embodiment of the present disclosure may be applied to a general washing machine having a drum with a vertical rotation shaft, or may be applied to a drum washing machine1having a horizontal rotation shaft.

Hereinafter, it will be described that the tub100is disposed in the drum washing machine1, as an example.

An outer appearance of the drum washing machine1may be formed by a main body10and a door20.

A space may be defined inside the main body10. The outer appearance of the main body10may be formed by a cabinet11, a top cover12, and a base fan13.

In detail, the cabinet11may be formed in a box shape with open top surface and bottom face. The cabinet11may form a peripheral surface of the main body10.

An entrance11athrough which the laundry passes may be defined in a front surface of the cabinet11.

The top cover12may be mounted on a top surface of the cabinet11to form a top surface of the main body10. That is, the top cover12may be provided to cover the top surface of the cabinet11.

The base fan13may be mounted on a bottom surface of the cabinet11to form a bottom surface of the main body10. That is, the base fan13may be provided to cover the bottom surface of the cabinet11.

The base fan13may have a bottom surface that covers the bottom surface of the cabinet11and edges protruding along a perimeter of the bottom surface.

The edges of the base fan13may be coupled to the cabinet11in a state overlapping with a lower peripheral surface of the cabinet11.

In one example, the base fan13may have electric parts mounting portions13aon which electric parts are mounted. The electrical parts may include a drain pump17to be described later.

The electric parts mounting portions13amay protrude from the bottom surface of the base fan13to allow the mounted electric parts to be spaced apart from the bottom surface of the base fan13. In this connection, the electric parts mounting portions13amay be applied in various sizes and shapes corresponding to types and shapes of the electric parts to be mounted.

The electric parts mounted on the electric parts mounting portions13aare spaced apart from the bottom surface of the base fan13, so that the electric parts may not be come into contact with water and protected even when water leaks inside the main body10.

In detail, in components in the main body10where washing water flows, leakage of the washing water may occur due to poor assembly or defective products.

For example, the leakage of the washing water may occur in the tub100, the water supply pipe16, the water discharge pipe18, or the like. When the washing water leaks, the leaked washing water may be collected in the base fan13. In this connection, when the electric parts mounted on the base fan13are located on the bottom surface of the base fan13, failure may occur due to the washing water.

However, the electric parts are mounted on the electric parts mounting portions13aand spaced apart from the bottom surface of the base fan13, so that contact with the leaked washing water may be prevented.

In one example, the base fan13may have a leakage detecting sensor70for detecting the occurrence of the leakage. The leakage detecting sensor70may be provided on the bottom surface of the base fan13.

In this connection, the bottom surface of the base fan13may be inclined downward toward a position where the leakage detecting sensor70is provided. For example, the leakage detecting sensor70may be located approximately at a center of the base fan13. The bottom surface of the base fan13may be inclined downward toward the center. Therefore, the water collected in the base fan13may be moved toward the leakage detecting sensor70, and the leakage may be detected quickly.

The leakage detecting sensor70may include various sensors capable of detecting the contact with water.

In one example, the drum washing machine1may include a controller for controlling overall operations. The leakage detecting sensor70may be connected to the controller and may output a detection signal to the controller when the leakage is detected.

The drum washing machine1may have an output device electrically connected to the controller for outputting an operation state of the drum washing machine1.

The output device may be a speaker for outputting sound. Alternatively, the output device may be a display for outputting texts or pictures.

The speaker and the display may be provided in the main body10. For example, the display may be provided on an upper portion of the front face of the main body10. Both or only one of the speaker and the display may be provided.

When the leakage is detected by the leakage detecting sensor70, the controller may output a specific alarm through the output device to allow a user to recognize an abnormal state of the product. Therefore, the user may recognize the occurrence of the leakage via the alarm, and may respond such as stopping use of the product, repair, or the like.

In one example, a manipulation unit14for manipulating the operation of the drum washing machine1may be disposed on the upper portion of the front surface. The manipulation unit14may be electrically connected to the controller to transmit a command input by the user to the controller.

A detergent box15that is retractable into and extendable out of the main body10may be provided at the upper portion of the front surface of the main body10. The user may inject detergent into the detergent box15by extending the detergent box15.

The main body10may include a water supply pipe16for supplying the washing water into the tub100. The water supply pipe16may be connected to an external water supply source and pass through one side of the main body10to extend inside the main body10.

The water supply pipe16may be connected to the tub100via the detergent box15to allow the detergent injected into the detergent box15to be supplied to the tub100together with the washing water.

The drain pump17and the water discharge pipe18for circulating or discharging the washing water may be arranged inside the main body10and below the tub100.

The drain pump17may be mounted on the electric parts mounting portion13aof the base fan13.

The water discharge pipe18may be connected to one side of the bottom face of the tub100and extend out of the main body10. The drain pump17may be connected to one side of the water discharge pipe18to force drainage of the washing water.

The door20may be pivotably provided on the front surface of the main body10. The door20may be provided to open and close the entrance11aby pivoting.

In one example, the drum washing machine1may include the tub100installed inside the main body10, the drum30rotatably installed in the tub100, wherein the washing of the laundry is performed in the drum30, and the motor40mounted on the tub100to rotate the drum30.

The tub100may be formed in a substantially cylindrical shape, and may define therein a washing space103filled with the washing water. The drum30may be received in the washing space103of the tub100.

The tub100may be in a form of lying in the main body10, and a front face thereof facing the entrance11amay be opened.

The tub100may be suspended by a spring19in the main body10.

A water collecting portion101for collecting the washing water therein may be formed in a lower portion of the tub100. The water collecting portion101is formed in a structure in which a bottom face thereof inside the tub100is recessed downward, so that the washing water may be easily collected therein.

A water drain hole102through which the washing water is discharged and in communication with the water discharge pipe18may be defined in the water collecting portion101.

The drum30is formed in a substantially cylindrical shape to define therein a space for receiving the laundry therein. In this connection, the drum30is formed to be smaller than the washing space103of the tub100, so that an outer face of the drum30may be spaced apart from an inner face of the tub100.

The drum30may be in a form of lying in the tub100and may be opened toward the entrance11a. Therefore, the laundry may be inserted into and removed out of the drum30through the entrance11a.

A plurality of holes31through which the washing water passes may be defined along a circumference of the drum30. When the drum30is rotated, the washing water supplied into the tub100may be supplied into the drum30or discharged out of the drum30through the holes31. That is, the washing water in the washing space103of the tub100may be circulated to the drum30.

The motor40may be provided on a rear side of the tub100. That is, the motor40may be provided out of a rear face of the tub100opposite to the opened front face of the tub100. A rotation shaft of the motor40may pass through the rear face of the tub100and be connected to the drum30.

In this connection, the rotation shaft of the motor40may be formed horizontally with the ground. That is, the drum30is rotated about the rotation shaft, which is horizontal to the ground, so that the laundry received therein may be moved upward and then dropped.

On an inner face of the drum30, a lift32for lifting the laundry during the rotation of the drum30may be disposed. The lift32may be provided to protrude from an inner circumference of the drum30. The lift32may include a plurality of lifts, and the plurality of lifts32may be spaced apart from each other along the inner circumference of the drum30.

When the washing machine1is operated for the washing, the washing water may be supplied into the washing space103of the tub100through the water supply pipe16. The washing water supplied into the tub100may be filled from a bottom of the tub100.

The washing water filled in the tub100may be circulated into the drum30through the holes31of the drum30.

When the washing water is sufficiently supplied into the tub100, the motor40may be operated to rotate the drum30. When the drum30is rotated, the laundry inside the drum30may be moved upward by the lift32and then be washed by the washing water while falling.

When the washing is completed, the motor40may be stopped, and the drain pump17may be operated. When the drain pump17is operated, the washing water inside the tub100may be discharged to the outside through the water drain hole102and the water discharge pipe18.

In one example, an outer appearance of the tub100may be formed by coupling of a plurality of divided components. That is, the tub100may be configured in a state in which the drum30is completely received therein by the coupling of the plurality of divided components.

Each of the plurality of components forming the outer appearance of the tub100may define a portion of the washing space103.

For example, an overall outer appearance of the tub100may formed by coupling of the first case300and the second case400.

The first case300and the second case400, which are plastic materials, may be injection-molded and provided. The first case300and the second case400may be coupled to each other by a welding process to form the outer shape of the tub100. In this connection, as the welding process, a welding method for generating vibrations in the first case300and the second case400may be applied.

The first case300may form approximately half of the tub100in the cylindrical shape. Further, the second case400may form the other half of the tub100in the cylindrical shape.

Referring toFIG. 1, it may be understood that the first case300forms a front portion of the tub100located close to the front face of the main body10. Accordingly, the first case300may be referred to as a ‘front case’.

It may be understood that the second case400forms a rear portion of the tub100located close to the rear face of the main body10. Accordingly, the second case400may be referred to as a ‘rear case’.

The first case300may be formed in a substantially cylindrical shape so as to define a portion of the washing space103. In this connection, the first case300may be formed in a cylindrical shape with opened front and rear faces.

That is, a front face of the first case300may be opened such that the laundry may be inserted therein and removed therefrom. A rear face of the first case300may also be opened such that an internal space of the first case300is in communication with an internal space of the second case400.

A front portion of the washing space103may be defined by the internal space of the first case300.

The second case400may be formed in a substantially cylindrical shape so as to define the remaining portion of the washing space103.

In this connection, the second case400may be formed in a cylindrical shape with an opened front face. That is, a front face of the second case400may be opened such that the internal space of the second case400is in communication with the internal space of the first case300.

A rear portion of the washing space103may be defined by the internal space of the second case400.

A shaft through-hole401through which the rotation shaft of the motor40passes may be defined in the rear face of the second case400.

Faces of the first case300and the second case400facing each other may be formed in a shape corresponding to each other. For example, the rear face of the first case300and the front face of the second case400may be formed in a ring shape having a size corresponding to each other.

Thus, the first case300and the second case400may form the outer appearance of the tub100by coupling of the faces facing each other, thereby defining the washing space103of the tub100.

The drum30may be inserted into an internal space of the first case300and the second case400in a state in which the first case300and the second case400are separated from each other. The drum30may be coupled to the rotation shaft of the motor40passing through the shaft through-hole401of the second case400.

The drum30may be rotatably received in the washing space103by the coupling of the first case300and the second case400.

In one example, the faces of the first case300and the second case400facing each other should be coupled with each other in an airtight manner such that leakage does not occur in the tub100.

To this end, coupling surfaces extending vertically outwards may be respectively formed on the faces of the first case300and the second case400that face each other.

In detail, a first coupling surface310extending vertically outwards along an outer circumference of the first case300may be formed on the rear face of the first case300. That is, the first coupling surface310extending vertically outwards along a circumference of the rear face may be formed on the rear face of the first case300.

A second coupling surface410extending vertically outwards along an outer circumference of the second case400may be formed on the front face of the second case400. That is, the second coupling surface410extending vertically outwards along a circumference of the front face may be formed on the front face of the second case400.

The first coupling surface310and the second coupling surface410may be formed to have a shape and area corresponding to each other.

The coupling surface310and the second coupling surface410may be bonded to each other by the welding process in an airtight manner.

Hereinafter, with reference to the drawings, structures and a coupling structure of the first case300and the second case400will be described in more detail.

FIG. 4is a rear perspective view of a first case according to an embodiment of the present disclosure.FIG. 5is an enlarged view of a lower portion of a first case according to an embodiment of the present disclosure.

The first coupling surface310may be formed on the rear face of the first case300.

A coupling protrusion320may be formed on the first coupling surface310.

The coupling protrusion320may protrude rearward from the rear face of the first case300. That is, the coupling protrusion320may protrude perpendicularly from the first coupling surface310.

The coupling protrusion320may be formed along the first coupling surface310and may be formed on an entirety of a circumference of the rear face of the first case300.

In detail, the coupling protrusion320may include a main coupling protrusion321and an auxiliary coupling protrusion322.

The main coupling protrusion321may be formed to be radially thicker than the auxiliary coupling protrusion322.

The main coupling protrusion321may be formed along the first coupling surface310and may be formed on an entirety of the circumference of the rear face of the first case300. That is, the main coupling protrusion321may have a closed ring structure formed along the circumference of the first coupling surface310.

The auxiliary coupling protrusion322may be formed along the first coupling surface310. In this connection, the auxiliary coupling protrusion322may be located outward of the main coupling protrusion321on the first coupling surface310. Further, the auxiliary coupling protrusion322may be spaced outward from the main coupling protrusion321.

In one example, the main coupling protrusion321is located inward than the auxiliary coupling protrusion322but located slightly spaced outward from an inner end of the first coupling surface310. That is, the main coupling protrusion321may be located between the auxiliary coupling protrusion322and the inner end of the first coupling surface310.

The auxiliary coupling protrusion322is located outward than the main coupling protrusion321but located slightly spaced inward from an outer end of the first coupling surface310. That is, the auxiliary coupling protrusion322may be located between the outer end of the first coupling surface310and the main coupling protrusion321.

In one example, the first coupling surface310is formed along an entirety of the circumference of the rear face of the first case300but a width thereof extending outward may be different depending on a formation position. That is, it may be seen that an area of the first coupling surface310is different depending on the formation position.

The auxiliary coupling protrusion322may be formed only on a portion of the first coupling surface310.

That is, the main coupling protrusion321may be formed on the entirety of the outer circumference of the first coupling surface310to encircle the washing space103, and the auxiliary coupling protrusion322may be formed only on a portion of the outer circumference the first coupling surface310.

In this connection, the auxiliary coupling protrusion322may be formed only on a portion of the first coupling surface310with a relatively large area.

In detail, in general, a height of the drum washing machine1may be greater than a width thereof.

That is, a vertical height of the cabinet11may be greater than a lateral width thereof. Therefore, a space with a vertical height greater than a lateral width thereof may be secured inside the cabinet11.

Therefore, a space in which the water supply pipe16extends and a space in which the spring19is disposed may be secured above the tub100and inside the cabinet11. In addition, a space in which components of the drain pump17, the water discharge pipe18, and the like are arranged may be secured below the tub100and inside the cabinet11.

As the internal space of the cabinet11is formed such that the vertical height thereof is greater than the lateral width thereof, an available space with a vertical height greater than a lateral width thereof may be further secured inside the cabinet11.

The tub100may be formed to have a lateral width corresponding to the lateral width of the internal space of the cabinet11so as to make the best use of the internal space of the cabinet11. That is, a diameter of a cross section of the tub100may be formed to have a length substantially close to the lateral width of the internal space of the cabinet11.

Therefore, the washing space103of the tub100may be secured to the maximum, and a washing capacity may be effectively secured by securing a maximum size of the drum30.

However, as the lateral width of the available space in the tub100inside the cabinet11is less than the vertical height thereof, the first coupling surface310and the second coupling surface410may be limited in length extending outward from left and right sides of the tub100.

Accordingly, the first coupling surface310and the second coupling surface410may have a length of portions thereof protruding from the left and right sides of the tub100less than a length of other portions. That is, the first coupling surface310and the second coupling surface410may have a relatively small width of the portions protruding from the left and right sides of the tub100.

In this connection, the first coupling surface310and the second coupling surface410may have ends thereof protruding from the left and right sides of the tub100in a form of a straight-line corresponding to left and right inner faces of the cabinet11. That is, straight portions311and411having outer ends thereof in a straight-line form may be formed at the left and right sides of the first coupling surface310and the second coupling surface410.

In one example, as the straight portion311formed on left and right sides of the first case300has a relatively small width, it may be difficult to secure an area for forming the main coupling protrusion321and the auxiliary coupling protrusion322together.

Therefore, only the main coupling protrusion321may be formed on the straight portion311formed at the left and right sides of the first case300.

In one example, a predetermined space may be defined inside the cabinet10and above the tub100. Various auxiliary apparatuses50to assist in the washing or drying the laundry may be further arranged in the space above the tub100.

For example, an opening through which air is flowed into or discharged from the tub100may be further defined in a top face of the tub100. The auxiliary apparatus50may be a duct for drying or heating the air flowed into the tub100.

Alternatively, the auxiliary apparatus50may be a heater that is connected to a water supply plate16passing through the space above the tub100and heats the washing water supplied into the tub100.

In order to prevent interference with the auxiliary apparatus50, the first coupling surface310and the second coupling surface410may be limited in length extending upwardly of the tub100.

Therefore, the first coupling surface310formed on an upper side of the first case300, and the second coupling surface410formed on an upper side of the second case400may have a relatively small width.

Therefore, only the main coupling protrusion321may be formed on the first coupling surface310formed on the upper side of the first case300.

It may be seen that the auxiliary coupling protrusion322is formed on the remaining portions of the first coupling surface310except for a portion of the first coupling surface310formed on the upper side of the case300and portions of the first coupling surface310formed on the left and right sides of the first case300.

That is, when viewing the rear face of the first case300straight, the auxiliary coupling protrusion322may be formed in a shape encircling the entire circumference of the lower portion of the first case300and encircling left and right regions except for a middle region of the circumference of the upper portion of the first case300.

It may be seen that the auxiliary coupling protrusion322is broken in response to the reduction of the width of the first coupling surface310at the left and right sides and the upper side of the first case300.

The broken end of the auxiliary coupling protrusion322may extend toward an adjacent main coupling protrusion321and may be connected to the main coupling protrusion321. Alternatively, the broken end of the auxiliary coupling protrusion322may be connected to the main coupling protrusion321by a connection rib323to be described later.

In one example, the connection rib323may be further provided in a portion in which the main coupling protrusion321and the auxiliary coupling protrusion322are formed together on the first coupling surface310.

The connection rib323may protrude in a space between the main coupling protrusion321and the auxiliary coupling protrusion322spaced apart from each other. The connection rib323may be formed to connect the main coupling protrusion321and the auxiliary coupling protrusion322with each other.

The connection rib323may include a plurality of connection ribs323spaced apart from each other in the space between the main coupling protrusion321and the auxiliary coupling protrusion322.

In this connection, the plurality of connection ribs323may be spaced apart from each other along the circumference of the rear face of the case300.

The main coupling protrusion321and the auxiliary coupling protrusion322may be supported by each other by the connection rib323, so that strengths of the main and auxiliary coupling protrusions321and322may be reinforced. Therefore, when an external impact is applied or in the welding process, the main coupling protrusion321and the auxiliary coupling protrusion322may be prevented from being folded or broken.

In one example, a lower portion of the washing space103, which is where the washing water is collected, may require more stable welding of the first case300and the second case400to prevent the leakage.

To this end, a distance between the plurality of connection ribs323may be reduced, so that the plurality of connection ribs323may be more densely arranged at the lower portion of the first case300.

Therefore, strengths of the main coupling protrusion321and the auxiliary coupling protrusion322at the lower side of the first case300may become higher. Accordingly, when the first case300and the second case400are welded with each other, the main coupling protrusion321and the auxiliary coupling protrusion322at the lower side of the first case300are more stably welded with each other.

In one example, the main coupling protrusion321and the auxiliary coupling protrusion322may protrude by heights corresponding to each other. Accordingly, the main coupling protrusion321and the auxiliary coupling protrusion322may be welded at the same time.

In one example, the connection rib323may protrude by a height less than that of the main coupling protrusion321and the auxiliary coupling protrusion322. In more detail, the connection rib323may have a height less than that of the main coupling protrusion321and the auxiliary coupling protrusion322in a state where the welding is completed.

Accordingly, division of the space between the main coupling protrusion321and the auxiliary coupling protrusion322by the connection rib323may be prevented. That is, the space between the main coupling protrusion321and the auxiliary coupling protrusion322may be defined in communication.

In one example, a structure in which the connection rib323is not disposed may be achieved.

In one example, when the drum washing machine1for washing the laundry is operated, the washing water may be limited to be filled to a vertical level lower than an intermediate vertical level of the washing space103.

For example, the washing water may be filled inside the washing space103, but may be limited to be filled to a vertical level lower than that of the straight portion311.

For example, the washing water may be limited in a supply amount to be filled to a vertical level equal to or below a height corresponding to a limiting level (H) of the washing water.

The main body10may further include a sensor for sensing an amount of the washing water supplied into the tub100or sensing a vertical level of the washing water filled in the tub100. The controller may control the supply amount of the washing water by controlling a water supply valve16a(seeFIG. 1) provided on the water supply pipe16.

In one example, when the space between the main coupling protrusion321and the auxiliary coupling protrusion322is blocked, it may be difficult to detect the leakage of the washing water resulted from poor welding, breakage, or the like of the main coupling protrusion321.

That is, when the welding failure or breakage of the main coupling protrusion321occurs, although the washing water may leak into the space between the main coupling protrusion321and the auxiliary coupling protrusion322, it may be difficult to grasp such a problem viewed from the outside.

When a situation in which the washing water leaks into the space between the main coupling protrusion321and the auxiliary coupling protrusion322is maintained, the main coupling protrusion321may be more damaged as the drum washing machine1continues to be used. When the situation leads to the breakage of the auxiliary coupling protrusion322, the washing water may lead to more serious problems, such as failure of the electric parts.

When the washing water leaked into the space between the main coupling protrusion321and the auxiliary coupling protrusion322is not discharged therefrom and is accumulated therein, hygiene issues such as an occurrence of mold may occur, and contamination of the laundry may occur.

Further, in order to prevent the above-mentioned problem, a discharge opening322afor communicating the space between the main coupling protrusion321and the auxiliary coupling protrusion322to the outside may be defined at one side of the tub100according to an embodiment of the present disclosure.

The discharge opening322amay be defined at a lower portion of the tub100and may be defined at a position vertically lower than the limiting level (H).

A welding quality of the coupling protrusion320encircling the region where the washing water is filled in the tub100may be seen as the most important.

As the discharge opening322ais defined at the position vertically lower than the limiting level (H), the washing water leaked into the space between the main coupling protrusion321and the auxiliary coupling protrusion322may be effectively discharged to the outside.

As an example, one side of the auxiliary coupling protrusion322may be outwardly opened to define the opening322a. That is, a portion of the auxiliary coupling protrusion322located at the bottom of the tub100may be cut to define the opening322a.

Referring toFIG. 5, the discharge opening322amay be defined at one side of the auxiliary coupling protrusion322located at the bottom of the tub100. In this connection, it may be seen that the discharge opening322ais defined in the auxiliary coupling protrusion322located at a central portion of the bottom of the tub100.

The space between the main coupling protrusion321and the auxiliary coupling protrusion322may be opened downward of the tub100through the opening322a.

The washing water leaked into the space between the main coupling protrusion321and the auxiliary coupling protrusion322may be collected in the space between the main coupling protrusion321and the auxiliary coupling protrusion322defined at the bottom of the tub100by gravity.

In more detail, the water collecting portion101recessed downward may be formed in the lower portion of the tub100. The discharge opening322amay be defined at a central position of the auxiliary coupling protrusion322surrounding the water collecting portion101. That is, the discharge opening322amay be defined at the central position of the auxiliary coupling protrusion322positioned below the water collecting portion101.

In this connection, the bottom of the tub100may be formed in a planar shape. As the bottom of the tub100at which a load of the washing water is concentrated is formed in the planar shape, the load may be distributed and a strength of the bottom of the tub100may become higher.

When the water collecting portion101is located at the bottom of the tub100, a bottom face of the water collecting portion101may be formed in a planar shape.

The first coupling surface310may be formed in a straight-line shape in a widthwise direction of the water collecting portion101which is perpendicular to an axial direction of the tub100on the bottom face of the water collecting portion101. That is, a lower-side straight portion312horizontal in the widthwise direction may be formed on the first coupling surface310positioned on the bottom face of the water collecting portion101.

The main coupling protrusion321and the auxiliary coupling protrusion322may be formed on the lower-side straight portion312in a straight-line shape in the widthwise direction of the water collecting portion101.

It may be seen that the discharge opening322ais defined in the auxiliary coupling protrusion322positioned at a central portion of the lower-side straight portion312.

The washing water leaked into the space between the main coupling protrusion321and the auxiliary coupling protrusion322may move downward and be discharged to the outside through the opening322a. The washing water discharged through the discharge opening322amay be collected into the base fan13.

The discharged washing water may move along the inclined bottom surface of the base fan13to be in contact with the leakage detecting sensor70provided on the base fan13. The leakage of the washing water may be detected by the leakage detecting sensor70, and the controller may notify the user of the occurrence of the leakage through the output device.

In one example, the guide member80for guiding the washing water discharged through the discharge opening322ato the leakage detecting sensor70may be further disposed.

The guide member80may be applied in a structure extending from the discharge opening322atoward the leakage detecting sensor70so as to guide the washing water to the leakage detecting sensor70. For example, the guide member80may be applied in a pipe structure extending from the discharge opening322ato the leakage detecting sensor70.

The guide member80is disposed, so that the position of the discharge opening322amay vary more freely. That is, even when the electrical parts are located below the opening322a, the discharged washing water may be guided to the guide member80and effectively guided to the leakage detecting sensor70without being in contact with the electric parts.

Further, the discharge opening322amay be defined at various positions at which the washing water collected in the lower portion of the tub100may be discharged to the outside. For example, the position of the discharge opening322amay be selected to avoid positions of the electric parts located below the tub100. Therefore, a problem in which the electric parts are come into contact with the washing water and damaged when the washing water is discharged may be prevented. Alternatively, the position of the discharge opening322amay be selected to minimize a problem of lowering of the strength of the tub100.

Hereinafter, another embodiment of the position of the discharge opening322awill be described with reference to the drawing.

FIG. 6shows a position of a discharge opening according to another embodiment of the present disclosure.

Further, the auxiliary coupling protrusion322may have a relatively weak strength of a portion in which the discharge opening322ais defined. The load of the washing water may be most concentrated at the central portion of the bottom of the tub100.

Thus, when the discharge opening322ais defined at the central portion of the bottom of the auxiliary coupling protrusion322where the load is most concentrated, problems may occur in the strength of the tub100.

Correspondingly, the discharge opening322amay be defined at the bottom of the tub100, and may be defined at a position biased in the widthwise direction of the water collecting portion101from the central portion of the bottom. That is, the discharge opening322amay be defined at one side of the auxiliary coupling protrusion322positioned at the bottom of the tub100, and may be defined at a position biased in the widthwise direction of the water collecting portion101from a central position of the auxiliary coupling protrusion322.

The discharge opening322amay be opened in a diagonal direction to face downward and sideward at a position biased in the widthwise direction from the central position of the auxiliary coupling protrusion322at the bottom of the tub100. In this connection, the discharge opening322amay be defined in the auxiliary coupling protrusion322positioned at an end of the lower-side straight portion312.

The discharge opening322amay be defined at both left and right sides of the bottom of the auxiliary coupling protrusion322, or may be defined at one of the left side and the right side.

In this connection, since the auxiliary coupling protrusion322located at the lower-side straight portion312is formed horizontally in the widthwise direction, even when the discharge opening322ais defined at a position biased in the widthwise direction from the central portion of the bottom, the leaked washing water may be effectively discharged.

Hereinafter, still another embodiment of the position of the discharge opening322awill be described with reference to the drawing.

FIG. 7shows a position of a discharge opening according to still another embodiment of the present disclosure.

The discharge opening322amay be defined penetrating the coupling surface positioned between the main coupling protrusion321and the auxiliary coupling protrusion322.

Since the discharge opening322ais defined in the coupling surface instead of the coupling protrusion, the strength of the coupling protrusion may be prevented from being lowered.

For example, the discharge opening322amay be defined in the first coupling surface310positioned between the main coupling protrusion321and the auxiliary coupling protrusion322. Alternatively, the discharge opening322amay be defined in the second coupling surface410positioned between the main coupling protrusion321and the auxiliary coupling protrusion322.

In this connection, the discharge opening322amay be defined penetrating the coupling surface located at the bottom of the tub100, and may be located at the length-direction central position at the bottom of the tub100.

In more detail, the water collecting portion101recessed downward may be formed in the lower portion of the tub100. The discharge opening322amay be defined in the coupling surface surrounding the water collecting portion101.

When the discharge opening322ais defined in the first coupling surface310, the discharge opening322amay be opened forward passing through the first coupling surface310. When the discharge opening322ais defined in the second coupling surface410, the discharge opening322amay be opened rearward passing through the second coupling surface410.

In one example, the discharge opening322amay be defined in both the first coupling surface310and the second coupling surface410.

FIG. 8is a front perspective view of a second case according to an embodiment of the present disclosure. Further,FIG. 9is a front view of a second case according to an embodiment of the present disclosure.

The second case400may be formed in the cylindrical shape with the open front face.

The through-hole401through which the rotation shaft of the motor40passes may be defined in the rear face of the second case400.

The second coupling surface410may be formed on the front face of the second case400.

The second coupling surface410may be formed to have a shape and an area corresponding to that of the first coupling surface310.

The second coupling surface410may provide a face on which the main coupling protrusion321and the auxiliary coupling protrusion322are welded.

In detail, during the welding process of the first case300and the second case400, the main coupling protrusion321and the auxiliary coupling protrusion322may be in contact with the second coupling surface410. By vibration supplied from a welding apparatus500(seeFIG. 11), the main coupling protrusion321and the auxiliary coupling protrusion322are melted by friction with the second coupling surface410, and then welded to the second coupling surface410.

In one example, a constraining protrusion420may be formed on the second coupling surface410. The constraining protrusion420may be formed along the second coupling surface410to have a closed loop structure encircling the internal space of the second case400.

The constraining protrusion420may provide a function of preventing flash F (seeFIG. 11) generated when the coupling protrusion320is welded to the second coupling surface410from flowing into the tub100. This will be described in more detail in a description referring toFIG. 11. For instance, the flash F may be a welding residue.

The constraining protrusion420may provide a function of reinforcing a strength of the second coupling surface410.

The constraining protrusion420may be formed along a circumference of the front face of the second case400and may protrude forwards. That is, the constraining protrusion420may protrude vertically from the second coupling surface410.

The constraining protrusion420may be formed to have a radial thickness less than the width of the second coupling surface410. The constraining protrusion420may be formed along an inner end of the second coupling surface410. Alternatively, the constraining protrusion420may be formed along the second coupling surface410at a position adjacent to the inner end of the second coupling surface410. Therefore, an area in which the coupling protrusion320is welded to the second coupling surface410may be secured outward of the constraining protrusion420.

In one example, a guide protrusion430may be further formed on the second coupling surface410. The guide protrusion430may protrude forward from the second coupling surface410.

The guide protrusion430may include a plurality of guide protrusions430radially arranged on the second coupling surface410around the internal space of the second case400.

For example, the plurality of guide protrusions430may be located to face an outer circumference of the second coupling surface410.

More specifically, the guide protrusions430may be formed on the second coupling surface410formed at the left and right sides of the second case400. Alternatively, the guide protrusions430may be formed on the second coupling surface410formed at the upper and lower sides of the second case400. As such, the guide protrusions430may be formed in regions of the second coupling surface410that are symmetric about the internal space of the second case400.

Hereinafter, an example in which the guide protrusions430are formed on the second coupling surface410formed on the left and right sides of the second case400will be described.

The plurality of guide protrusions430may be arranged on the second coupling surface410of the left and right sides of the second case400. In this connection, the plurality of guide protrusions430may be spaced apart from each other along the inner end of the second coupling surface410on the left and right sides.

The guide protrusion430may have a radial thickness less than the width of the second coupling surface410. Therefore, an area in which the coupling protrusion320is welded to the second coupling surface410may be secured outward of the guide protrusion430.

The guide protrusion430may have a slanted face declined outwardly of the second coupling surface410. That is, a height of the guide protrusion430may be lowered outwardly of the second coupling surface410.

In this connection, a vertical portion431may be formed at an outer end of the guide protrusion430. The vertical portion431may be perpendicular to the second coupling surface420.

The guide protrusion430may provide a function of guiding a position at which the first case300is coupled to the second case400. The guide protrusion430may provide a function of reinforcing a coupling strength of the first case300and the second case400and preventing deformation of the tub100.

In detail, when the first coupling surface310and the second coupling surface410are positioned to face each other for the welding of the first case300and the second case400, the coupling protrusion320may be guided to a correct position of the second coupling surface410to be welded by the declination of the guide protrusion430. That is, the coupling protrusion320may be guided to the second coupling surface410outward of the guide protrusion430by the declination of the guide protrusion430.

An inner face of the coupling protrusion320is supported on the vertical portion431of the guide protrusion430, so that the coupling protrusion320may be maintained at the correct position on the second coupling surface410. Therefore, the coupling protrusion320may be stably welded at the correct position of the second coupling surface410.

As the inner face of the coupling protrusion320is supported to the guide protrusion430, the coupling strength of the tub100may be reinforced and the deformation of the tub100may be prevented.

In one example, the plurality of guide protrusions430spaced apart from each other may be connected with each other by the constraining protrusion420. That is, both the constraining protrusions420and the guide protrusions430are arranged along the inner end of the second coupling surface410, so that positions of the constraining protrusions420and the guide protrusions430may overlap. In this connection, the constraining protrusion420may be formed to connect the plurality of guide protrusions430with each other in a space between the plurality of guide protrusions430.

The radial thickness of the constraining protrusion420may be less than that of the guide protrusion430. The constraining protrusion420may be positioned such that an outer face thereof is connected to the vertical portion431of the guide protrusion430.

FIG. 10is a rear view of a tub according to an embodiment of the present disclosure. Further,FIG. 11is a view illustrating a welding structure of an upper portion of a tub by cutting the tub along an A′-A″ line ofFIG. 10.

The welding structure shown inFIG. 11is not limited to a welding structure of the upper side of the tub100. Further, it may be seen that the welding structure shown inFIG. 11is a welding structure in which the main coupling protrusion321is formed on the first coupling surface310and the constraining protrusion420is formed on the second coupling surface410.

Hereinafter, referring toFIG. 11, the welding structure in which the main coupling protrusion321is formed on the first coupling surface310and the constraining protrusion420is formed on the second coupling surface410will be described in detail.

As the coupling protrusion320is welded to the second coupling surface410by the welding process, the first coupling surface310and the second coupling surface410may be bonded to each other.

In this connection, a welding method for generating vibrations in the first case300and the second case400may be applied to the welding process.

For example, as the welding method for generating the vibrations, various welding methods such as an ultrasonic welding method, a vibration welding method, and the like may be applied.

The ultrasonic welding method is a welding method in which vertical vibrations are supplied to parts using an ultrasonic welding apparatus that generates ultrasonic waves, so that two parts in contact with each other are rubbed by the vibrations and welded to each other. The ultrasonic welding method is a well-known welding method, so that a detailed description of the ultrasonic welding method will be omitted.

The vibration welding method is a welding method in which horizontal vibrations are supplied to parts using a vibration apparatus that generates the vibration, so that two parts in contact with each other are rubbed by the vibration and welded to each other. The vibration welding method is a well-known welding method, so that a detailed description of the vibration welding method will be omitted.

For the welding, the first case300and the second case400may be aligned such that the first coupling surface310and the second coupling surface410face each other.

In a state in which the first coupling surface310and the second coupling surface410are aligned to face each other, a protruding end portion of the main coupling protrusion321may be in contact with the second coupling surface410.

In a state in which the main coupling protrusion321is in contact with the second coupling surface410, the welding apparatus500may be injected outward of the first coupling surface310and the second coupling surface410to pressurize from outward of the first coupling surface310and the second coupling surface410. The protruding end portion of the main coupling protrusion321may come in close contact with the second coupling surface410by the injection of the welding apparatus500.

In a state in which the main coupling protrusion321is in close contact with the second coupling surface410, vibration may be supplied by the welding apparatus500, and then frictional heat may be generated by the vibration at a contact portion between the main coupling protrusion321and the second coupling surface410. The main coupling protrusion321may be melted and welded to the second coupling surface410by the frictional heat.

In one example, during the welding process, the flash F may occur in a process in which the coupling protrusion320is melted and then solidified again. The flash F is a lump of molten raw material of the coupling protrusion320.

The flash F generated during the welding may be generated inward and outward of the coupling protrusion320. The flash F generated outward of the coupling protrusion320may be discharged out of the tub100through the space between the first coupling surface310and the second coupling surface410. In this connection, the flash F generated outward of the coupling protrusion320may be fossilized and remain in the space between the first coupling surface310and the second coupling surface410. However, the flash F is blocked by the coupling protrusion320and is not flowed into the tub100.

On the other hand, the flash F generated inward of the coupling protrusion320may be flowed into the tub100through the space between the first coupling surface310and the second coupling surface410.

Therefore, a process for removing the flash F flowed into the tub100may be required, and as a result, producing time and costs of the tub100may be increased.

In addition, even when the process for removing the flash F flowed into the tub100is performed, the flash F may remain inside the tub100. Alternatively, the flash F may remain between the first coupling surface310and the second coupling surface410, and may be flowed into the tub100when the washing machine1that has been assembled is used. In this case, when the user uses the washing machine1, the flash F may contaminate the laundry, thereby causing a great dissatisfaction of the user.

Therefore, a structure capable of preventing the flash F from flowing into the tub100is required.

In one example, in the embodiment of the present disclosure, the constraining protrusion420is disposed to effectively prevent the flash F from flowing into the tub100.

In detail, when the first case300and the second case400are coupled to each other, the constraining protrusion420may be located inward of the coupling protrusion320or may be positioned to be spaced inwardly of the coupling protrusion320.

That is, the constraining protrusion420may be located closer to the washing space103of the tub100than the main coupling protrusion321and the auxiliary coupling protrusion322. Accordingly, a space in which the flash F is constrained may be secured between the coupling protrusion320and the constraining protrusion420.

In this connection, the inner face of the constraining protrusion420may be located on the same extension line as a circumference of the internal space of the first case300. Therefore, in the coupling of the first case300and the second case400, the constraining protrusion420may not protrude into the washing space103of the tub100, thereby preventing interference with flow of the washing water in the tub100or interference with the drum30.

A protruding height of the constraining protrusion420may be less than that of the coupling protrusion320.

For example, the constraining protrusion420may protrude to a height corresponding to a height of the coupling protrusion320lowered by the welding process. For example, the constraining protrusion420may protrude to a height equal to or less than the height of the coupling protrusion320melted by the welding process.

Therefore, in a state in which the welding coupling between the first case300and the second case400is completed, the protruding end portion of the constraining protrusion420may be adjacent to or in contact with the first coupling surface310. Therefore, the flash F may be stably constrained in the space between the coupling protrusion320, thereby effectively preventing the flash F from flowing into the tub100.

That is, referring toFIG. 11, the flash F generated inward of the main coupling protrusion321is constrained in the space between the main coupling protrusion321and the constraining protrusion420, so that the flash F does not flow into the tub100.

In one example, the main coupling protrusion321may be located approximately at a width-direction center of the first coupling surface310. Therefore, the vibration may be effectively transmitted to the main coupling protrusion321from the welding apparatus500, so that the welding may be performed stably.

FIG. 12is a view illustrating a welding structure of left and right portions of a tub by cutting the tub along a B′-B″ line ofFIG. 10.

The welding structure shown inFIG. 12is not limited to a welding structure of the left and right sides of the tub100. Further, it may be seen that the welding structure shown inFIG. 12is a welding structure in which only the main coupling protrusion321is formed on the first coupling surface310and the guide protrusion430and the constraining protrusion420are formed on the second coupling surface410.

Hereinafter, referring toFIG. 11, the welding structure in which only the main coupling protrusion321is formed on the first coupling surface310and the guide protrusion430and the constraining protrusion420are formed on the second coupling surface410will be described in detail.

When the coupling protrusion320of the first coupling surface310is aligned to be in contact with the second coupling surface410for the welding, the coupling protrusion320may be guided to a correct position of the second coupling surface410by the inclination of the guide protrusion430.

For example, when misalignment or deformation of the first coupling surface310and the second coupling surface410occurs, the main coupling protrusion321may come into contact with the slanted face of the guide protrusion430. The main coupling protrusion321may be moved outward along the slanted face of the guide protrusion430and then be guided to the second coupling surface410, which is to be welded, outward of the guide protrusion430.

In a state in which the protruding end portion of the main coupling protrusion321is in contact with the second coupling surface410, the inner face of the main coupling protrusion321may be in contact with the vertical portion431of the guide protrusion430, thereby remaining at the correct welding position without moving inward or outward.

In one example, as the welding position of the coupling protrusion320is aligned and maintained in a region where the guide protrusion430is formed, the coupling protrusion320in a region where the guide protrusion430is not formed may also be aligned and maintained at the correct position of the second coupling surface410to be welded.

In one example, even in the region where the guide protrusion430is formed, the flash F to be generated during the welding may be generated inward and outward of the coupling protrusion320.

The flash F generated outward of the main coupling protrusion321may be discharged out of the tub100through the space between the first coupling surface310and the second coupling surface410.

The flash F generated inward of the main coupling protrusion321may be constrained in the space between the guide protrusion430and the main coupling protrusion321. That is, the flash F may be prevented from flowing into the tub100by being constrained between the main coupling protrusion321and the slanted face of the guide protrusion430.

To this end, the guide protrusion430may be have a height corresponding to a height of the coupling protrusion320lowered by the welding process. Therefore, in a state in which the welding coupling between the first case300and the second case400is completed, the protruding end portion of the guide protrusion430may be adjacent to or in contact with the first coupling surface310.

Therefore, the flash F may be stably constrained in the space between the coupling protrusion320, thereby effectively preventing the flash F from flowing into the tub100.

Alternatively, the guide protrusion430may have a height greater than the height of the coupling protrusion320melted and lowered by the welding process.

In this case, in the state in which the welding coupling of the first case300and the second case400is completed, the guide protrusion430may be formed such that the slanted face thereof is adjacent to or in contact with the inner end of the first coupling surface310.

In detail, the inner end, which is protruded to the maximum, of the guide protrusion430may be located inward than the circumference of the internal space of the first case300. Therefore, in the state in which the welding coupling between the first case300and the second case400is completed, the slanted face of the guide protrusion430may be adjacent to or in contact with the inner end of the first coupling surface310. Even in this case, the flash F may be stably constrained in the space between the coupling protrusion320.

In one example, the main coupling protrusion321may be located approximately at a width-direction center of the first coupling surface310. Therefore, the vibration may be effectively transmitted to the main coupling protrusion321from the welding apparatus500, so that the welding may be performed stably.

FIG. 13is a view illustrating a welding structure of a lower portion of a tub by cutting the tub along a C′-C″ line ofFIG. 10.

The welding structure shown inFIG. 13is not limited to a welding structure of the lower side of the tub100. Further, it may be seen that the welding structure shown inFIG. 13is a welding structure in which both the main coupling protrusion321and the auxiliary coupling protrusion322are formed on the first coupling surface310and the constraining protrusion420is formed on the second coupling surface410.

Hereinafter, referring toFIG. 13, the welding structure in which both the main coupling protrusion321and the auxiliary coupling protrusion322are formed together on the first coupling surface310and the constraining protrusion420is formed on the second coupling surface410will be described in detail.

The main coupling protrusion321may be approximately positioned at a width-direction center of the first coupling surface310. Therefore, the vibration may be effectively transmitted to the main coupling protrusion321from the welding apparatus500and the welding may be stably performed even when the radial thickness of the main coupling protrusion321is greater than that of the auxiliary coupling protrusion322.

The auxiliary coupling protrusion322may be located outward of the main coupling protrusion321and spaced apart from the main coupling protrusion321. In this connection, the auxiliary coupling protrusion322may be located closer to the outer end than the inner end of the first coupling surface310.

Thus, the auxiliary coupling protrusion322is positioned outward from the width-direction center of the first coupling surface310, so that the vibration may not be stably transmitted from the welding apparatus500to the auxiliary coupling protrusion322than to the main coupling protrusion321. However, since the radial thickness of the auxiliary coupling protrusion322is less than the radial thickness of the main coupling protrusion321, the welding may be performed stably.

In one example, for the welding process, when the coupling protrusion320of the first coupling surface310is aligned to be in contact with the second coupling surface410, the constraining protrusion420may be located inward of the main coupling protrusion321and may be positioned to be spaced inwardly from the main coupling protrusion321.

That is, the constraining protrusion420may be located closer to the washing space103than the main coupling protrusion321. Accordingly, a space in which the flash F is constrained may be secured between the main coupling protrusion321and the constraining protrusion420.

In this connection, the inner face of the constraining protrusion420may be located on the same extension line as the circumference of the internal space of the first case300. Therefore, the constraining protrusion420may not protrude into the washing space103when the first case300and the second case400are coupled to each other.

In one example, the flash F generated during the welding may be generated inward and outward of the main coupling protrusion321, and inward and outward of the auxiliary coupling protrusion322.

The flash F generated outward of the auxiliary coupling protrusion322may be discharged out of the tub100through the space between the first coupling surface310and the second coupling surface410.

The flash F generated inward of the auxiliary coupling protrusion322and outward of the main coupling protrusion322may be constrained in the space between the main coupling protrusion321and the auxiliary coupling protrusion322and may not be flowed into the tub100.

The flash F generated inward of the main coupling protrusion321may be constrained in the space between the main coupling protrusion321and the constraining protrusion420and may not be flowed into the tub100.

That is, the flash F generated inward of the main coupling protrusion321may be prevented from being flowed into the tub100by the guide protrusion430in the region of the second coupling surface410in which the guide protrusion430is formed.

In one example, the coupling protrusion320is formed on the first coupling surface310, and the constraining protrusion420and the guide protrusion430are formed on the second coupling surface410facing the first coupling surface310, so that the flash F may be more effectively.

In detail, since the constraining protrusion420and the guide protrusion430are not be welded, in a state in which the coupling protrusion320is welded and shortened, the constraining protrusion420and the guide protrusion430are adjacent to or in contact with the first coupling surface310to block a passage through which the flash F flows into the tub100.

That is, in a state in which the welding of the coupling protrusion320is not completed, a relatively large space may be generated between the first coupling surface310and the constraining protrusion420and between the first coupling surface310and the guide protrusion430. In this connection, the relatively large space between the first coupling surface310and the constraining protrusion420and between the first coupling surface310and the guide protrusion430may have a size enough for the flash F to be flowed therein.

However, since an end of the coupling protrusion320in contact with the second coupling surface410is welded, the flash F is generated at the second coupling surface410side. That is, the flash F is accumulated from the second coupling surface410side in the space between the first coupling surface310and the second coupling surface410.

In this connection, since the constraining protrusion420protrudes from the second coupling surface410, the flash F accumulated from the second coupling surface410side may be effectively prevented from flowing into the tub100.

That is, even though the relatively large space is generated between the first coupling surface310and the constraining protrusion420in a state in which welding of the coupling protrusion320is not completed, the flash F may be blocked by the constraining protrusion420protruding from the second coupling surface410and may not be flowed into the tub100.

Similarly, since the guide protrusion430protrudes from the second coupling surface410, the flash F accumulated from the second coupling surface410side may be effectively prevented from flowing into the tub100.

That is, even though the relatively large space is generated between the first coupling surface310and the guide protrusion430in a state in which welding of the coupling protrusion320is not completed, the flash F may be blocked by the guide protrusion430protruding from the second coupling surface410and may not be flowed into the tub100.

Further, in the embodiment of the present disclosure, it has been described that the coupling protrusion320is formed on the first case300, and the constraining protrusion420and the guide protrusion430are formed on the second case400. However, it is noted that the embodiment of the present disclosure is not limited thereto.

In detail, the constraining protrusion420and the guide protrusion430are formed on the first case300, and the coupling protrusion320may be formed on the second case400.

Further, in the embodiment of the present disclosure, it has been described that the constraining protrusion420is formed along the inner end of the second coupling surface410to be positioned inward of the coupling protrusion320. However, the constraining protrusion420may be further formed outward of the coupling protrusion320. That is, the constraining protrusion420may be further formed along the outer end of the second coupling surface410. Therefore, the flash F may be prevented from being discharged out of the tub100through the space between the first coupling surface310and the second coupling surface410.

Following effects may be expected in the tub of the washing machine and the washing machine including the same, according to the embodiment of the present disclosure.

First, in the coupling of the first case and the second case that form the tub with each other by the welding, the first coupling surface and the second coupling surface facing each other may be respectively formed on the first case and the second case. The first coupling surface includes the coupling protrusion for coupling the first case and the second case with each other by the welding process.

In this connection, the coupling protrusion includes the main coupling protrusion formed along the first coupling surface and the auxiliary coupling protrusion spaced outwardly from the main coupling protrusion. Therefore, as the main coupling protrusion and the auxiliary coupling protrusion are formed together, more firm welding coupling between the first case and the second case may be achieved. Further, the leakage of the water may be effectively prevented from occurring in the coupling portion of the first case and the second case.

Second, the opening for communicating the auxiliary coupling protrusion and the main coupling protrusion with the outside is defined in the bottom of the tub. Because of the opening, even when the leakage of the water occurs due to the poor welding of the main coupling protrusion or the damage to the main coupling protrusion, the washing water may be discharged to the outside without being constantly accumulated in the space between the main coupling protrusion and the auxiliary coupling protrusion. Therefore, the hygiene issues of the laundry resulted by the accumulation of the washing water may be prevented.

Third, the opening is defined at a position vertically lower than the limiting level (H) of the washing water filled in the washing space. Therefore, all of the washing water leaked between the main coupling protrusion and the auxiliary coupling protrusion may be immediately and effectively discharged to the outside.

Fourth, since the auxiliary coupling protrusion is formed to have a radial thickness less than that of the main coupling protrusion, even when the auxiliary coupling protrusion is formed together with the main coupling protrusion, the welding of the main coupling protrusion and the auxiliary coupling protrusion may be achieved stably.

Fifth, the plurality of connection ribs are formed to connect the main coupling protrusion and the auxiliary coupling protrusion with each other. Accordingly, the main coupling protrusion and the auxiliary coupling protrusion may be supported by each other by the plurality of connection ribs, thereby improving the strengths thereof. Therefore, the main coupling protrusion and the auxiliary coupling protrusion may be prevented from being folded or broken when the external impact is applied or in the welding process. In addition, as the strengths of the main coupling protrusion and the auxiliary coupling protrusion are reinforced, the first case and the second case may be more firmly coupled to each other.

In particular, as the connection rib is formed to have a height less than that of the coupling protrusion in a state where the welding is completed, the space between the main coupling protrusion and the auxiliary coupling protrusion may not be blocked by the connection rib and may be in communication with the opening. Therefore, when the washing water leaks into the space between the main coupling protrusion and the auxiliary coupling protrusion, the leaked washing water may be moved to the bottom of the tub and be effectively discharged to the outside through the opening.

Sixth, the first coupling surface extends outward of the circumference of the first case, and the second coupling surface extends outward of the circumference of the second case. Therefore, an area in which the welding apparatus is contact with and presses the first coupling surface and the second coupling surface from outward thereof may be secured.

Seventh, in the state in which the first coupling surface and the second coupling surface are bonded to each other, the constraining protrusion located inward of the coupling protrusion protrudes from the second coupling surface. Therefore, the flash generated when the coupling protrusion is welded may be prevented from flowing into the washing space.

In this connection, the constraining protrusion is formed on the second coupling surface facing the first coupling surface where the coupling protrusion is formed, so that the flash may be effectively prevented from flowing into the washing space during the welding of the coupling protrusion.

That is, an end of the coupling protrusion in contact with the second coupling surface is melted, so that the flash is generated on the second coupling surface side and is accumulated from the second coupling surface side in the space between the first coupling surface and the second coupling surface. In this connection, the constraining protrusion is formed to protrude from the second coupling surface, so that the flash accumulated from the second coupling surface side may be effectively prevented from flowing into the tub.

Eighth, the guide protrusion for guiding the coupling protrusion to the coupling surface outward of the constraining protrusion is formed on the second coupling surface, and the guide protrusions are formed at both sides of the second coupling surface facing each other around the internal space of the second case. In addition, the guide protrusion has a slanted face declined downwards.

Therefore, the coupling protrusion may be accurately guided to the second coupling surface outward of the constraining protrusion to be welded by the slanted face of the guide protrusion. That is, the coupling protrusion is guided to the correct position of the second coupling surface by the guide protrusion, so that stable welding may be achieved.

Ninth, the base forming the bottom face of the cabinet has the leakage detecting sensor for detecting the leakage when in contact with the washing water, and the cabinet has the output device for outputting information. The controller is provided to output a notification through the output device when the leakage is detected.

Accordingly, when the washing water leaked through the opening is discharged, the discharged washing water may be collected in the base and come into contact with the leakage detecting sensor. Then, the controller may inform the user of the occurrence of the leakage through the output device. Thus, the user may cope with the leakage.

Tenth, there is provided the guide member extending from the opening toward the leakage detecting sensor to guide the washing water discharged through the opening to the leakage detecting sensor. As the guide member is provided, the washing water discharged from the opening may be prevented from contacting and damaging the electric parts arranged in the cabinet. That is, the washing water discharged from the opening may be reliably guided to the leakage detecting sensor, thereby preventing further failure due to the leakage.