Laundry treating apparatus and drum manufacturing method
The drum design with recesses and protrusions in the lifter assembly disperses stress, addressing manufacturing and use-related damage issues, improving durability and performance.
Patent Information
- Authority / Receiving Office
- US · United States
- Patent Type
- Applications(United States)
- Current Assignee / Owner
- LG ELECTRONICS INC
- Filing Date
- 2023-11-21
- Publication Date
- 2026-07-23
Smart Images
Figure US20260210018A1-D00000_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a laundry treating apparatus and a method for manufacturing a drum.BACKGROUND
[0002] A laundry treating apparatus for treating laundry includes a washing machine, a dryer, and the like. The laundry treating apparatus, such as the washing machine, the dryer, and the like, and a method for manufacturing a drum include the drum that may be rotatably operated. The drum of the laundry treating apparatus and the method for manufacturing the drum accommodates the laundry therein. The laundry accommodated in the drum is treated by various operations performed by the laundry treating apparatus.
[0003] The drum may include a lifter disposed on an inner circumferential surface thereof. Korean Patent Publication Application No. 10-2011-0022359 discloses that the lifter disposed on the inner circumferential surface lifts the laundry when the drum rotates.
[0004] Because the lifter lifts the laundry, it provides an advantageous effect on the various treatments performed by the laundry treating apparatus. For example, in a case of the washing machine, a frictional action between the laundry and a washing power may be secured higher when the lifter is present than when the lifter is not present.
[0005] Korean Patent Publication Application No. 10-2020-0025557 discloses that a metal plate forming the drum is plastically processed to form the lifter. When the metal plate is processed to form the lifter, and the metal plate that has formed the lifter is rolled in a cylindrical shape and both ends thereof are joined together to manufacture the drum, a portion where the lifter is formed may be deformed (or broken) during the process of rolling the metal plate. In addition, the manufactured drum may be prone to the breakage because a rigidity of the portion where the lifter is formed is lower than that of other portions.SUMMARYTechnical Problem
[0006] The present disclosure provides a laundry treating apparatus and a method for manufacturing a drum that may reduce damage (e.g., tearing and collapse) caused by a load in a case of forming a lifter by bending a metal plate for manufacturing the drum (hereinafter, a drum with a forming-type lifter structure).
[0007] The present disclosure provides a laundry treating apparatus and a method for manufacturing a drum that may reduce damage by dispersing stress applied to a lifter of a drum with a forming-type lifter structure.
[0008] The present disclosure provides a laundry treating apparatus and a method for manufacturing a drum that may avoid a risk of tearing during a process of rolling a metal plate into a cylindrical shape in a manufacturing process of a drum with a forming-type lifter structure.
[0009] The present disclosure provides a laundry treating apparatus and a method for manufacturing a drum that may reduce a risk of drum damage caused by load during use.
[0010] Problems to be solved by the present disclosure are not limited thereto, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.Technical Solutions
[0011] According to an embodiment, provided is a laundry treating apparatus including a drum, wherein the drum includes a cylindrical portion, a lifter assembly formed by protruding inwardly of the cylindrical portion as the cylindrical portion is bent, wherein the lifter assembly has a major axis in a front and rear direction, and a recess defined as the cylindrical portion is bent at a lifter periphery constituting a periphery of the lifter assembly, wherein the recess is defined in at least a portion between a first position, a point at the lifter periphery, and a second position, a point on a side opposite to the first position based on the major axis of the lifter assembly.
[0012] Further, the recess may be formed by protruding outwardly of the cylindrical portion.
[0013] Further, the recess may include a first recess, and a second recess following a shape of the first recess, wherein the second recess is more spaced apart from the lifter assembly than the first recess is.
[0014] Further, the drum may further include a recess-defining protrusion spaced apart from the lifter assembly and formed to protrude inwardly of the cylindrical portion as the cylindrical portion is bent, and the recess may be defined between the lifter assembly and the recess-defining protrusion.
[0015] Further, the recess-defining protrusion may include a first recess-defining protrusion formed to be spaced apart from the lifter assembly by a first distance, and a second recess-defining protrusion formed to be spaced apart from the lifter assembly by a second distance, wherein the recess includes a first recess defined between the lifter assembly and the first recess-defining protrusion, and a second recess defined between the first recess-defining protrusion and the second recess-defining protrusion.
[0016] Further, the recess may be defined throughout the entire lifter periphery.
[0017] Further, the cylindrical portion may be formed by rolling a metal plate made of a metal material.
[0018] Further, the lifter assembly may be composed of a plurality of groups, wherein each group is composed of a plurality of lifters, and the plurality of groups may be arranged equiangularly.
[0019] Further, the plurality of lifters constituting each group may be arranged to be misaligned with each other with respect to the front and rear direction.
[0020] Further, the lifter assembly may include a plurality of front lifters arranged equiangularly, and a plurality of rear lifters arranged equiangularly and disposed rearward of the front lifters, and the recess may include a front lifter recess defined in a front lifter periphery constituting a periphery of each front lifter, and a rear lifter recess defined in a rear lifter periphery constituting a periphery of each rear lifter.
[0021] Further, the front lifter recess may be defined at least at the rear of the front lifter periphery.
[0022] Further, the rear lifter recess may be defined at least in front of the rear lifter periphery.
[0023] Further, the drum may be rotatable.
[0024] Further, the laundry treating apparatus may further include a tub constructed to accommodate the drum therein, and the drum may be rotatably disposed inside the tub.
[0025] According to an embodiment, provided is a method for manufacturing a drum for a laundry treating apparatus, including a bending step of bending a metal plate to form a lifter assembly having a first height and a recess having a first depth, and a joining step of rolling the metal plate into a cylindrical shape and joining both ends thereof to each other after the bending step.
[0026] Further, the first height may have a value greater than the first depth.
[0027] Further, the recess may be defined by a recess-defining protrusion that bends the metal plate to have a second height in the same direction as a protrusion direction of the lifter assembly.
[0028] Further, the recess may be defined by bending the metal plate to have the first depth in a direction opposite to the protrusion direction of the lifter assembly.
[0029] The above-described laundry treating apparatus may be a washing machine.
[0030] The above-described laundry treating apparatus may be a dryer.Advantageous Effects
[0031] According to the laundry treating apparatus and the method for manufacturing the drum according to the various embodiments of the present disclosure, the damage (e.g., the tearing and the collapse) caused by the load may be reduced in the case of forming the lifter by bending the metal plate for manufacturing the drum (hereinafter, the drum with the forming-type lifter structure).
[0032] According to the various embodiments of the present disclosure, the damage may be reduced by dispersing the stress applied to the lifter of the drum with the forming-type lifter structure.
[0033] According to the various embodiments of the present disclosure, the risk of the tearing during the process of rolling the metal plate into the cylindrical shape may be avoided in the manufacturing process of the drum with the forming-type lifter structure.
[0034] According to the various embodiments of the present disclosure, the risk of the drum damage caused by the load may be reduced during the use.
[0035] Effects of the present disclosure are not limited to the effects described above, and effects not mentioned will be clearly understood by a person skilled in the art to which the present disclosure belongs from the present document and the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a cross-sectional view schematically illustrating a laundry treating apparatus according to an embodiment of the present disclosure.
[0037] FIG. 2 is an exploded perspective view of a drum 40 according to an embodiment of the present disclosure.
[0038] FIG. 3 is a front view of a cylindrical portion 41 according to an embodiment of the present disclosure.
[0039] FIG. 4 is a plan view of a metal plate 41′ for manufacturing the cylindrical portion 41 according to a first embodiment of the present disclosure, and is an enlarged view of a portion where a lifter assembly 1410 and a recess 1415 according to the first embodiment are formed.
[0040] FIG. 5 is an enlarged view of a portion A in FIG. 4.
[0041] FIG. 6 is a cross-sectional view taken along a line I-I′ that is a minor axis of a front lifter 1410a in FIG. 5.
[0042] FIG. 7 is a cross-sectional view taken along a line II-II′ that is a major axis of the front lifter 1410a in FIG. 5.
[0043] FIG. 8 is a diagram for illustrating the recess 1415 according to a first embodiment, and is an enlarged view of a portion B in FIG. 7.
[0044] FIG. 9 is a plan view of the metal plate 41′ for manufacturing the cylindrical portion 41 according to a second embodiment of the present disclosure, and is an enlarged view of a portion where a lifter assembly 2420 and a recess 2415 according to the second embodiment are formed.
[0045] FIG. 10 is an enlarged view of a portion C in FIG. 9.
[0046] FIG. 11 is a cross-sectional view taken along a line I-I′, which is a minor axis of a rear lifter 2410b in FIG. 10.
[0047] FIG. 12 is a cross-sectional view taken along a line II-II′, which is a major axis of the rear lifter 2410b in FIG. 10.
[0048] FIG. 13 is a diagram for illustrating a recess 2415 according to a second embodiment, and is an enlarged view of a portion D in FIG. 12.
[0049] FIG. 14 is a plan view of a metal plate for manufacturing a cylindrical portion according to a third embodiment of the present disclosure, and is an enlarged view of a portion where a lifter assembly and a recess according to the third embodiment are formed.
[0050] FIG. 15 is an enlarged view of a portion E in FIG. 14.
[0051] FIG. 16 is a cross-sectional view taken along a line I-I′, which is a minor axis of a front lifter 2410a in FIG. 15.
[0052] FIG. 17 is a cross-sectional view taken along a line II-II′, which is a major axis of the front lifter 2410a in FIG. 15.
[0053] FIG. 18 is a stress simulation in a structure where the recess 1415 is not applied.
[0054] FIG. 19 is a stress simulation applied with the same conditions (a lifter shape, a load, and the like) as in FIG. 18, but in a structure where the recess 1415 is applied.
[0055] FIG. 20 illustrates agitation of laundry caused by a rotation speed of the drum 40. (a) in FIG. 20 illustrates a case when the drum 40 rotates at a relatively low speed. (b) in FIG. 20 illustrates a case when the drum 40 rotates at a higher speed than in the case of (a) in FIG. 20. (c) in FIG. 20 illustrates a case when the drum 40 rotates at a higher speed than in the case of (b) in FIG. 20.
[0056] FIG. 21 schematically illustrates stress acting on a drum 141 according to an embodiment of the present disclosure and stress distribution at a vulnerable portion.
[0057] FIG. 22 schematically illustrates stress acting on a drum 241 according to another embodiment of the present disclosure and stress distribution at a vulnerable portion.BEST MODE
[0058] Hereinafter, an embodiment of the present disclosure will be described with reference to the attached drawings. In describing the embodiment of the present disclosure, the description will be made in detail such that a person having ordinary skill in the art to which the present disclosure belongs may easily implement the same.
[0059] The present disclosure may be implemented in various embodiments and may not be limited to the embodiment described herein. To clearly illustrate the present disclosure in the drawings, parts that are not related to the description may be omitted. Similar parts in the drawings are given similar reference numerals throughout the present document.
[0060] In the present document, descriptions that are deemed redundant are generally omitted.Definition of Terms
[0061] A term “laundry treating apparatus” used in a following description means any apparatus capable of treating laundry, such as washing, drying, or refreshing the laundry.
[0062] A term “treatment of laundry” used in the following description means the treatment, such as washing, sterilization, bleaching, softening, and drying, performed on the laundry. The treatment of the laundry may be achieved by cycles and courses performed by the laundry treating apparatus. One or more cycles are combined with each other to constitute the course. The one or more cycles may be listed in a chronological order and may be combined with each other to constitute the course. The cycles include a washing cycle, a rinsing cycle, a dehydration cycle, a drying cycle, a cooling cycle, a refreshing cycle, and the like. The washing cycle is a cycle of separating foreign substances attached to the laundry with water and detergent. The rinsing cycle is a cycle of separating the laundry and the foreign substances from each other with water. The dehydration cycle is a cycle of removing water from the laundry. The drying cycle is a cycle of removing moisture from the laundry. The cooling cycle is a cycle of lowering a temperature of the heated laundry. The refreshing cycle is a cycle of performing at least one of deodorization, wrinkle removal, and sterilization on the laundry using at least one of air and steam.
[0063] The term “detergent” used in the following description means any substance used to sterilize, disinfect, or remove impurities from the laundry, fibers, or the like. In an embodiment, the detergent may be a solid in a powder form or a liquid.
[0064] A term “softener” used in the following description means any substance or agent used to make the laundry, the fibers, or the like soft and smooth.
[0065] A term “bleach” used in the following description means any substance or agent that chemically decomposes and removes colored substances contained in the fibers or the like to make the fibers or the like white.
[0066] A term “treatment agent” used in the following description means any substance that may cause a chemical or physical action to treat the laundry. In an embodiment, the treatment agent may be used with a meaning including the detergent, the softener, the bleach, and the like.
[0067] A term “fluid” used in the following description means any fluid that may be mixed with the laundry treatment agent or act as a solvent for the laundry treatment agent. In an embodiment, the fluid may be washing water, i.e., water.
[0068] Terms “upper side”, “lower side”, “left side”, “right side”, “front side”, and “rear side” used in the following description will be understood with reference to a coordinate system of the drawings. Such terms are used for convenience of description and are intended only to intuitively describe relative arrangement relationships, not to limit the invention by the terms themselves. For convenience of description, referring to the coordinate system, the upper side is denoted as Z, the left side as X, and the front side as Y.
[0069] In the present document, when a component is referred to as being ‘connected’ or ‘coupled’ to another component, it should be understood that it may be ‘directly connected’ or ‘directly coupled’ to said another component, but there may be another component therebetween. On the other hand, in the present document, when a component is referred to as being ‘directly connected’ or ‘directly coupled’ to another component, it should be understood that there is no component therebetween.
[0070] The terms used in the present document are used only to describe a specific embodiment, and are not intended to limit the present disclosure. For example, when a lower-level concept term (e.g., a spring) is used instead of a higher-level concept term (e.g., an elastic member) to easily describe the embodiment, this is intended to describe the embodiment, and is not intended to limit the invention to the lower-level concept.
[0071] In the present document, a singular expression may include a plural expression unless the context clearly indicates otherwise.
[0072] In the present document, a term “include” or “have” is intended to specify presence of a feature, a number, a step, an operation, a component, a part, or a combination thereof described in the present document, and should be understood as not excluding in advance a possibility of presence or addition of one or more other features, numbers, steps, operations, components, parts, or a combination thereof.
[0073] In the present document, a term “and / or” includes a combination of a plurality of described items or any item among the plurality of described items. For example, “a and / or b” means “a and b”, “a”, or “b”. Furthermore, “a or b” may be interpreted as meaning “a”, “b”, or “both a and b”.Embodiment
[0074] FIG. 1 is a cross-sectional view schematically illustrating a laundry treating apparatus according to an embodiment of the present disclosure. A laundry treating apparatus and drum-manufactured apparatus 1 shown in FIG. 1 and described as one embodiment is a washing machine. The laundry treating apparatus 1 according to an embodiment will be described with reference to FIG. 1.
[0075] The laundry treating apparatus 1 includes a cabinet 10, a door 15, a tub 30, a drum 40, a drum driver 50, a detergent supplier 60, a water supplier 70, a drain / circulation unit 80, and the like.
[0076] The cabinet 10 forms an outer appearance of the laundry treating apparatus 1. An inlet is defined in a front surface of the cabinet 10. The door 15 is coupled to the inlet. The door 15 may be pivotably coupled to the cabinet 10. When the door 15 is opened, interior of the drum 40 is accessible.
[0077] The tub 30 is placed inside the cabinet 10. The tub 30 is a water tank for storing washing water as needed. The tub 30 may be supported by various components. In an embodiment, the tub 30 may be supported by a damper 20. The damper 20 reduces vibration occurring in the tub 30. A front surface of the tub 30 is open and is in communication with the inlet of the cabinet 10.
[0078] The drum 40 is placed inside the tub 30. The drum 40 is installed so as to be rotatable. The drum 40 may include a cylindrical portion 41, a rear surface 42, and a front surface 43. The cylindrical portion 41 may be in a form in which a plate of a metal material (e.g., stainless steel) is rolled up and both ends thereof are joined to each other. The cylindrical portion 41 has an overall cylindrical shape. It should be understood that the cylindrical shape here does not mean a cylinder in a mathematically or geometrically strict sense. The rear surface 42 closes an open rear surface of the cylindrical portion 41. The rear surface 42 is coupled to the cylindrical portion 41 at the rear of the cylindrical portion 41. The front surface 43 has an opening defined therein such that the laundry may be put into the drum 40, and is in communication with the inlet of the cabinet 10. The rear surface 42 and the front surface 43 may be made of a metal material like the cylindrical portion 41. A plurality of through-holes may be defined in the drum 40, so that washing water may be exchanged between the tub 30 and the drum 40. Via the plurality of through-holes defined in the drum 40, washing water contained in the tub 30 may be introduced into the drum 40, or washing water inside the tub 30 may be discharged to the outside. The cylindrical portion 41 of the drum 40 and an inner surface of the tub 30 are spaced apart from each other.
[0079] The drum 40 is coupled with the drum driver 50 that rotates the drum 40. In an embodiment, the drum driver 50 may be an electric motor including a stator and a rotor. The drum driver 50 includes a rotation shaft 51. The rotation shaft 51 extends through a rear surface of the tub 30 and is coupled to the rear surface 42 of the drum 40. More specifically, the rear surface 42 of the drum 40 may be coupled to a spider that is coupled to the rotation shaft 51.
[0080] A lifter assembly 410 is formed on the drum 40. The lifter assembly 410 is formed on the cylindrical portion 41 of the drum 40. In an embodiment of the present disclosure, the lifter assembly 410 includes a plurality of lifters formed along a circumferential direction of the cylindrical portion 41. The plurality of lifters of the lifter assembly 410 arranged along the circumferential direction may constitute one group. According to the embodiment shown, each of a front lifter 410a and a rear lifter 410b is provided as a single group. The lifter assembly 410 according to an embodiment of the present disclosure is formed by bending the cylindrical portion 41. The lifter assembly 410 will be described in more detail below.
[0081] The detergent supplier 60 may include a detergent dispenser 61 and a detergent supply pipe 65. The detergent dispenser 61 is a component that accommodates the detergent and / or the softener therein. The detergent supply pipe 65 is a component that forms a flow channel for supplying the detergent and / or the softener accommodated in the detergent dispenser 61 to the tub 30.
[0082] The water supplier 70 is a component that supplies water to the tub 30. The water supplier 70 may include a water supply valve 71 and a water supply pipe 75. When the water supply valve 71 is opened and water is supplied, water is supplied to the laundry treating apparatus 1 via the water supply pipe 75. In an embodiment, the water supply pipe 75 may be connected to the detergent supplier 60. Water introduced via the water supplier 70 may be supplied to the detergent dispenser 61 and draw the detergent and / or the softener contained in the detergent dispenser 61 into the tub 30. Water introduced into the detergent dispenser 61 via the water supply pipe 75 may be mixed with the detergent and / or the softener and supplied to the tub 30 via the detergent supply pipe 65.
[0083] The drain / circulation unit 80 is a component that circulates water accommodated in the tub 30 or drains water accommodated in the tub 30 to the outside. In the embodiment, a drain unit and a circulation unit are combined with each other and described as the drain / circulation unit 80, but the drain unit and the circulation unit may be provided separately. The drain / circulation unit 80 according to an embodiment of the present disclosure may include a pump unit 81, a discharge hose 82, a circulation hose 83, and a drain hose 84.
[0084] The pump unit 81 may be provided with a drain pump and a circulation pump. In addition, a drain filter (not shown) may be built into the pump unit 81.
[0085] The discharge hose 82 connects the tub 30 with the pump unit 81. The discharge hose 82 is connected to an inlet of the pump unit 81. Water in the tub 30 may be discharged from the tub 30 via the discharge hose 82 and introduced into the pump unit 81.
[0086] The circulation hose 83 connects the pump unit 81 with the tub 30. The pump unit 81 may transfer inflowed water to the circulation hose 83 and supply water back to the tub 30. In an embodiment, the pump unit 81 may be provided with the circulation pump, one end of the circulation hose 83 may be connected to an outlet of the circulation pump, and the other end of the circulation hose 83 may be connected to the tub 30. By the operation of the circulation pump, washing water accommodated in the tub 30 is supplied back to the tub 30 via the discharge hose 82, the pump unit 81, and the circulation hose 83. In an embodiment, various functions may be performed while washing water is circulated.
[0087] The drain hose 84 connects the pump unit 81 with the outside of the laundry treating apparatus 1. In an embodiment, the pump unit 81 may be provided with the drain pump, and one end of the drain hose 84 may be connected to an outlet of the drain pump. Further, the other end of the drain hose 84 is placed outside the laundry treating apparatus 1. The other end of the drain hose 84 is positioned at an appropriate drain hole based on an installation environment. By the operation of the drain pump, washing water accommodated in the tub 30 is discharged to the outside of the laundry treating apparatus via the discharge hose 82, the pump unit 81, and the drain hose 84.
[0088] FIG. 2 is an exploded perspective view of the drum 40 according to an embodiment of the present disclosure. FIG. 3 is a front view of the cylindrical portion 41 according to an embodiment of the present disclosure. Referring to FIGS. 2 and 3, the drum 40 according to an embodiment of the present disclosure will be described.
[0089] The drum 40 may include the cylindrical portion 41, the rear surface 42, and the front surface 43. The cylindrical portion 41 may be in the form in which the plate of the metal material (e.g., stainless steel) is rolled in a hollow cylindrical shape and both ends thereof are joined to each other. The joining of the both ends may be accomplished by applying various known processing techniques such as curling, seaming, and welding. The cylindrical portion 41 has the overall cylindrical shape. It should be understood that the cylindrical shape here does not mean the cylinder in the mathematically or geometrically strict sense. The rear surface 42 closes the open rear surface of the cylindrical portion 41. The rear surface 42 is coupled to the cylindrical portion 41 at the rear of the cylindrical portion 41. The coupling of the rear surface 42 and the cylindrical portion 41 may be accomplished by applying various known processing techniques such as curling, seaming, and welding. The front surface 43 may be formed with a drum opening 43a such that the laundry may be inserted into the drum 40, and may be in communication with the inlet of the cabinet 10. The coupling of the front surface 43 and the cylindrical portion 41 may be accomplished by applying various known processing techniques such as curling, seaming, and welding. The rear surface 42 and the front surface 43 may be made of a metal material like the cylindrical portion 41. The plurality of through-holes may be defined in the drum 40, so that washing water may be exchanged between the tub 30 and the drum 40. Via the plurality of through-holes defined in the drum 40, washing water contained in the tub 30 may be introduced into the drum 40, or washing water inside the tub 30 may be discharged to the outside. To clearly reveal the lifter assembly 410, the through-holes defined in the cylindrical portion 41 are not illustrated in FIG. 2.
[0090] The lifter assembly 410 may include multiple lifters formed along the circumferential direction. The plurality of lifters of the lifter assembly 410 constitute one group. In the illustrated example, three lifter groups 411, 412, and 413 are provided, and each group includes two lifters. In an embodiment, a first lifter group 411 is composed of a first lifter 411a and a second lifter 411b. In an embodiment, a second lifter group 412 includes a first lifter 412a and a second lifter 412b. In an embodiment, a third lifter group 413 includes a first lifter 413a and a second lifter 413b. According to an embodiment of the present disclosure, the first lifter group 411, the second lifter group 412, and the third lifter group 413 are arranged equiangularly with respect to a rotation shaft O (see FIG. 3) of the drum 40. The rotation shaft O may be defined by the rotation shaft 51. Here, “equiangular” does not mean the cylinder in the mathematically and geometrically strict sense, and should be understood to include an equivalent range and an error range. According to an embodiment of the present disclosure, each lifter group 411, 412, and 413 includes the plurality of lifters, so that each lifter assembly 410 may reduce a length of a major axis. When the major axis length of the lifter assembly 410 is great, there is a risk that a center of the lifter assembly 410 will be damaged. On the other hand, when the length of the lifter assembly 410 is small, stress is concentrated on an end in the major axis, and there is a risk that the end where the stress is concentrated will be damaged (see FIGS. 21 and 22).
[0091] Based on a definition according to the present disclosure, the first lifter 411a, the first lifter 412a, and the first lifter 413a correspond to the front lifter 410a. Further, the second lifter 411b, the second lifter 412b, and the second lifter 413b correspond to the rear lifter 410b. In the present document, a name of each lifter is defined based on a front and rear direction of the drum 40, and is not intended to limit the scope of the claims.
[0092] FIG. 4 is a plan view of a metal plate 41′ for manufacturing the cylindrical portion 41 according to a first embodiment of the present disclosure, and is an enlarged view of a portion where a lifter assembly 1410 according to the first embodiment is formed. A description will be made with reference to FIG. 4.
[0093] The metal plate 41′ may be embossed to reinforce strength. According to an embodiment of the present disclosure, the embossing may be formed by bending the metal plate 41′ inwardly or outwardly relative to a reference portion 41a of the metal plate. The bending of the metal plate 41′ may be obtained by plastic processing of the metal plate 41′. Hereinafter, the reference portion 41a of the metal plate may also be regarded as a reference portion of the cylindrical portion 41. Because the cylindrical portion 41 is manufactured by rolling the metal plate 41′ into a circular shape, the reference portion of the metal plate 41′ becomes the reference portion of the cylindrical portion 41.
[0094] A first embossing 41b and a second embossing 41c may be formed on the metal plate 41′. The first embossing 41b and the second embossing 41c may protrude in opposite directions. In an embodiment, the first embossing 41b is a protrusion that protrudes the metal plate 41′ outwardly of the drum 40. The second embossing 41c is a protrusion that protrudes the metal plate 41′ inwardly of the drum 40. A plane of the first embossing 41b may be circular. The first embossing 41b may be formed to have an overall curved surface. The first embossing 41b may be spherical. A plane of the second embossing 41c may be circular. The second embossing 41c may be formed to have an overall curved surface. The second embossing 41c may be spherical. The first embossing 41b and the second embossing 41c may be formed with different sizes. For example, diameters of the planes thereof may be different from each other. In addition, protruding heights thereof may be different from each other. In an embodiment, the first embossing 41b has a smaller plane diameter than the second embossing 41c. The first embossing 41b and the second embossing 41c may be formed in a staggered arrangement. In an embodiment, protrusions forming the second embossing 41c are disposed between a plurality of protrusions forming the first embossing 41b. A through-hole 41d may be defined at a portion where the first embossing 41b is formed. The through-hole 41d may be defined at a center of the first embossing 41b. Because the washing machine is described as an embodiment, the through-hole 41d is described, but in the case of a dryer, the through-hole 41d will not be defined.
[0095] As an embodiment of the lifter assembly 410 described above, the lifter assembly 1410 according to the first embodiment is provided. The lifter assembly 1410 may include a front lifter 1410a and a rear lifter 1410b. The lifter assembly 1410 protrudes to have a protruding height greater than that of the first embossing 41b and the second embossing 41c. The lifter assembly 1410 is formed to protrude inwardly of the cylindrical portion 41. The lifter assembly 1410 may be formed by protruding the metal plate 41′ by 10 mm or greater from the reference portion 41a of the metal plate. In one example, the lifter assembly 1410 performs a function of lifting the laundry accommodated in the drum 40, and it is sufficient for the lifter assembly 1410 to protrude with a height appropriate for performing the lifting function thereof. A numerical value described in the present document is for enhancing understanding of the lifter assembly 1410.
[0096] The lifter assembly 1410 has a major axis in the front and rear direction. In an embodiment, the front lifter 1410a has a major axis in the front and rear direction. The rear lifter 1410b has a major axis in the front and rear direction. In an embodiment, the front lifter 1410a is positioned on a first axis a. The rear lifter 1410b is positioned on a second axis b. The first axis a and the second axis b are spaced apart from each other by a predetermined distance d. In an embodiment, the rear lifter 1410b is formed at a position shifted in one of left and right directions from the front lifter 1410a when viewed from the front. The front lifter 1410a and the rear lifter 1410b are arranged to be misaligned with each other with respect to the front and rear direction. According to the arrangement of the lifter assembly 1410 according to the first embodiment, a problem of reduced formability between the front lifter 1410a and the rear lifter 1410b may be solved. In addition, laundry distribution inside the drum 40 during washing may be improved. In addition, a dehydration entry rate may be improved.
[0097] FIG. 5 is an enlarged view of a portion A in FIG. 4. Hereinafter, the portion A where the front lifter 1410a is formed will be described as an example. However, because structures of the front lifter 1410a and the rear lifter 410b may be identical, a description of the rear lifter 1410b will be replaced by the description of the front lifter 1410a. FIG. 6 is a cross-sectional view taken along a line I-I′ that is a minor axis of the front lifter 1410a in FIG. 5. FIG. 7 is a cross-sectional view taken along a line II-II′ that is a major axis of the front lifter 1410a in FIG. 5. The first embodiment of the present disclosure will be described with further reference to FIGS. 6 and 7 in addition to FIG. 5.
[0098] The front lifter 1410a is formed to protrude inwardly of the drum 40. In FIGS. 6 and 7, the inward direction of the drum 40 is expressed as an upward direction in the drawings. The front lifter 1410a may be formed to protrude with a cross-section that becomes narrower as it gets farther away from the reference portion 41a of the metal plate. The front lifter 1410a may be formed to have an uppermost end protruding from the reference portion 41a of the metal plate by a first height h1. An inclined surface curved portion 1412 may be formed on an inclined surface of the front lifter 1410a. The front lifter 1410a according to an embodiment may be formed with a first inclined surface curved portion 1412a and a second inclined surface curved portion 1412b. The first inclined surface curved portion 1412a and the second inclined surface curved portion 1412b reinforce strength of the front lifter 1410a. As an embodiment, it is illustrated that the inclined surface curved portion 1412 is formed in two pieces, but the number thereof may be appropriately increased or decreased depending on a design. An upper end curved portion 1413 may be formed at an upper portion of the front lifter 1410a. The upper end curved portion 1413 reinforces rigidity of the upper portion of the front lifter 1410a. In an embodiment, the upper end curved portion 1413 is formed to have a concave shape at an uppermost end.
[0099] A periphery of the lifter assembly 1410 on the metal plate 41′ forming the cylindrical portion 41 is defined as a lifter periphery A1. The lifter periphery A1 may follow the shape in which the front lifter 1410a protrudes. In the illustrated embodiment, the lifter periphery A1 forming a periphery of the front lifter 1410a is provided. The lifter periphery A1 may mean an area with a predetermined length from a portion where the front lifter 1410a begins to protrude from the reference portion 41a of the metal plate in a direction away from the front lifter 1410a.
[0100] A recess 1415 is defined in the lifter periphery A1. The recess 1415 is defined by processing the metal plate 41′. The recess 1415 is defined by bending the metal plate 41′ forming the cylindrical portion 41. When the front lifter 1410a is defined in a convex shape, the recess 1415 is defined in a concave shape.
[0101] In the illustrated embodiment, the recess 1415 is formed entirely along the lifter periphery A1 and surrounding the periphery of the front lifter 1410a. However, the scope of the claims is not limited to such a drawing. In the illustrated embodiment, the recess 1415 may be formed in the lifter periphery A1, but may be formed in at least a portion A1′ between a first position P1, which is a point at the lifter periphery A1, and a second position P2, which is a point located opposite to the first point P1 with respect to a major axis.
[0102] The recess 1415 is also defined around the rear lifter 1410b. A description of the recess 1415 defined around the rear lifter 1410b is replaced with the description of the recess 1415 surrounding the front lifter 1410a. Because stress is concentrated at a portion where the front lifter 1410a and the rear lifter 1410b face each other, it is preferable that the recess 1415 is defined at least at the portion where the stress is concentrated. Therefore, a front lifter recess defined around the front lifter 1410a is formed at least at the rear of the front lifter periphery, and a rear lifter recess defined around the rear lifter 1410b is formed at least in front of the rear lifter periphery.
[0103] FIG. 8 is a diagram for illustrating the recess 1415, and is an enlarged view of a portion B in FIG. 7. A description will be made with reference to FIG. 8. The recess 1415 has a depth d1 and a width w1. In an embodiment, the present inventers identify that the greater the depth d1 of the recess 1415 and the smaller the width w1, the more advantageous it is. However, the depth d1 of the recess 1415 is limited by a gap between the drum 40 and the tub 30. Although the recess 1415 protrudes outward, there is a gap between a portion where the recess 1415 is defined and an inner wall of the tub 30. The recess 1415 is not a component for reinforcing strength or rigidity, but rather a component for dispersing the concentrated stress. The recess 1415 is formed in the lifter periphery A1, and is formed along the shape in which the lifter assembly 1410 protrudes from the metal plate 41′. In other words, it is formed in the lifter periphery A1, which is the portion where the lifter assembly 1410 begins to protrude from the reference portion 41a of the metal plate. Therefore, when the recess 1415 is defined in the portion where the stress is concentrated, an area size where the stress is applied increases, and thus the stress is distributed, reducing a risk of damage. FIG. 18 is a stress simulation in a structure where the recess 1415 is not applied, and FIG. 19 is a stress simulation applied with the same conditions (a lifter shape, a load, and the like) as in FIG. 18, but in a structure where the recess 1415 is applied. Referring to FIG. 19, it may be seen that the stress concentrated in a portion indicated by P3 in FIG. 18 is distributed.
[0104] FIG. 9 is a plan view of the metal plate 41′ for manufacturing the cylindrical portion 41 according to a second embodiment of the present disclosure, and is an enlarged view of a portion where a lifter assembly 2420 according to a second embodiment is formed. A description will be made with reference to FIG. 9. In FIG. 9, a description of other components except for a lifter assembly 2410 according to the second embodiment is replaced with the description in FIG. 4.
[0105] As an embodiment of the lifter assembly 410 described above, the lifter assembly 2410 according to the second embodiment is provided. The lifter assembly 2410 may include a front lifter 2410a and a rear lifter 2410b. The lifter assembly 2410 protrudes with a protruding height greater than that of the first embossing 41b and the second embossing 41c. The lifter assembly 2410 is formed to protrude inwardly of the cylindrical portion 41. The lifter assembly 2410 may be formed by protruding the metal plate 41′ by 10 mm or greater from the reference portion 41a of the metal plate. In one example, the lifter assembly 2410 performs the function of lifting the laundry accommodated in the drum 40, and it is sufficient for the lifter assembly 2410 to protrude with a height appropriate for performing the lifting function thereof. A numerical value described in the present document is for enhancing understanding of the lifter assembly 2410.
[0106] The lifter assembly 2410 has the front and rear direction as a major axis thereof. In an embodiment, the front lifter 2410a has the front and rear direction as a major axis thereof. The rear lifter 2410b has the front and rear direction as a major axis thereof. In an embodiment, the front lifter 2410a is positioned on the first axis a. The rear lifter 2410b is positioned on the second axis b. The first axis a and the second axis b are spaced apart from each other by the predetermined distance d. In an embodiment, the rear lifter 2410b is formed at a position shifted in one of the left and right directions from the front lifter 2410a when viewed from the front. The front lifter 2410a and the rear lifter 2410b are arranged to be misaligned with each other with respect to the front and rear direction. According to the arrangement of the lifter assembly 2410 according to the second embodiment, a problem of reduced formability between the front lifter 2410a and the rear lifter 2410b may be solved. In addition, the laundry distribution inside the drum 40 during the washing may be improved. In addition, the dehydration entry rate may be improved.
[0107] FIG. 10 is an enlarged view of a portion C in FIG. 9. The portion C where the rear lifter 2410b is formed is described as an example, but because structures of the rear lifter 2410b and the front lifter 2410a may be identical, a description of the front lifter 2410a is replaced by the description of the rear lifter 2410b. FIG. 11 is a cross-sectional view taken along a line I-I′, which is a minor axis of the rear lifter 2410b in FIG. 10. FIG. 12 is a cross-sectional view taken along a line II-II′, which is a major axis of the rear lifter 2410b in FIG. 10. The second embodiment of the present disclosure will be described with further reference to FIGS. 11 and 12 in addition to FIG. 10.
[0108] The rear lifter 2410b is formed to protrude inwardly of the drum 40. In FIGS. 11 and 12, the inward direction of the drum 40 is expressed as an upward direction in the drawings. The rear lifter 2410b may be formed to protrude with a cross-section that becomes narrower as it gets farther away from the reference portion 41a of the metal plate. The rear lifter 2410b may be formed to have an uppermost end protruding from the reference portion 41a of the metal plate by a first height h2. An inclined surface curved portion 2412 may be formed on an inclined surface of the rear lifter 2410b. The rear lifter 2410b according to an embodiment may be formed with a first inclined surface curved portion 2412a and a second inclined surface curved portion 2412b. The first inclined surface curved portion 2412a and the second inclined surface curved portion 2412b reinforce strength of the rear lifter 2410b. As an embodiment, it is illustrated that the inclined surface curved portion 2412 is formed in two pieces, but the number thereof may be appropriately increased or decreased depending on a design. An upper end curved portion 2413 may be formed at an upper portion of the rear lifter 2410b. The upper end curved portion 2413 reinforces rigidity of the upper portion of the rear lifter 2410b. In an embodiment, the upper end curved portion 2413 is formed to have a concave shape at an uppermost end.
[0109] A periphery of the lifter assembly 2410 on the metal plate 41′ forming the cylindrical portion 41 is defined as a lifter periphery A2. The lifter periphery A2 may follow the shape in which the rear lifter 2410b protrudes. In the illustrated embodiment, the lifter periphery A2 forming a periphery of the rear lifter 2410b is provided. The lifter periphery A2 may mean an area with a predetermined length from a portion where the rear lifter 2410b begins to protrude from the reference portion 41a of the metal plate in a direction away from the rear lifter 2410b.
[0110] A recess 2415 is defined in the lifter periphery A2. The recess 2415 is defined by processing the metal plate 41′. The recess 2415 is defined by bending the metal plate 41′ forming the cylindrical portion 41. In the illustrated embodiment, the recess 2415 is formed entirely along the lifter periphery A2 and surrounding a periphery of the lifter periphery A2. However, the scope of the claims is not limited to such a drawing. In an embodiment, the lifter periphery A2 may be formed at the rear lifter 2410b, but may be formed in at least a portion A2′ between the recess 2415, which is a point at a first position P1, and a second position P2, which is a point located opposite to the first point P1 with respect to a major axis.
[0111] The recess 2415 is also defined around the front lifter 2410a. A description of the recess 2415 defined around the front lifter 2410a is replaced with the description of the recess 2415 surrounding the rear lifter 2410b. Because stress is concentrated at a portion where the rear lifter 2410b and the front lifter 2410a face each other, it is preferable that the recess 2415 is defined at least at the portion where the stress is concentrated. Therefore, a front lifter recess defined around the front lifter 2410a is formed at least at the rear of the front lifter periphery, and a rear lifter recess defined around the rear lifter 2410b is formed at least in front of the rear lifter periphery.
[0112] FIG. 13 is a diagram for illustrating the recess 2415, and is an enlarged view of a portion D in FIG. 12. A description will be made with reference to FIG. 13.
[0113] The recess 2415 has a depth d2 and a width w2. In an embodiment, the present inventers identify that the greater the depth d2 of the recess 2415 and the smaller the width w2, the more advantageous it is. According to an embodiment, a depth d2 of a recess-defining protrusion 2416 is defined by the protruding height of the recess 2415. In one example, a protruding height of the recess-defining protrusion 2416 is smaller than the height h2 of the lifter assembly 2410.
[0114] The recess 2415 is defined between the lifter assembly 2410 and the recess-defining protrusion 2416. In other words, the recess 2415 may be defined by a relationship between the lifter assembly 2410 and the recess-defining protrusion 2416. The recess-defining protrusion 2416 is formed by bending the cylindrical portion 41. The recess-defining protrusion 2416 is formed by bending the cylindrical portion 41 inwardly. The recess-defining protrusion 2416 is formed at a position spaced apart from the lifter assembly 2410. The recess 2415 is defined by the separation between the lifter assembly 2410 and the recess-defining protrusion 2416. The recess 2415 is a concept that includes a concavely curved shape.
[0115] The recess 2415 is not a component for reinforcing strength or rigidity, but rather a component for dispersing the concentrated stress. The reference portion 41a of the metal plate is formed at the recess 2415, and is formed along the shape in which the lifter periphery A2 protrudes from the lifter assembly 2410. In other words, it is formed at the recess 2415, which is the portion where the metal plate 41′ begins to protrude from the lifter periphery A2. Therefore, when the lifter assembly 2410 is formed in the portion where the stress is concentrated, an area size where the stress is applied increases, and thus the stress is distributed, reducing a risk of damage.
[0116] FIG. 14 is a plan view of the metal plate 41′ for manufacturing the cylindrical portion 41 according to a third embodiment of the present disclosure, and is an enlarged view of a portion where the lifter assembly 2410 and a recess 3415 are formed. A description will be made with reference to FIG. 14. Because the lifter assembly 2410 illustrated in FIG. 14 is the same as the lifter assembly 2410 described in FIGS. 9 to 12, a description thereof is replaced with the above description. The recess 3415 is defined around the lifter assembly 2410.
[0117] FIG. 15 is an enlarged view of a portion E in FIG. 14. The lifter assembly 2410 is the same as the lifter assembly 2410 described in FIGS. 9 to 12. However, to enrich the description, a description will be made based on the front lifter 2410a in FIG. 15. FIG. 16 is a cross-sectional view taken along a line I-I′, which is a minor axis of the front lifter 2410a in FIG. 15. FIG. 17 is a cross-sectional view taken along a line II-II′, which is a major axis of the front lifter 2410a in FIG. 15. The third embodiment of the present disclosure will be described with further reference to FIGS. 16 and 17 in addition to FIG. 15.
[0118] The front lifter 2410a is formed to protrude inwardly of the drum 40. In FIGS. 16 and 17, the inward direction of the drum 40 is expressed as an upward direction in the drawings. The front lifter 2410a may be formed to protrude with a cross-section that becomes narrower as it gets farther away from the reference portion 41a of the metal plate. The front lifter 2410a may be formed to have an uppermost end protruding from the reference portion 41a of the metal plate by a first height h2. The inclined surface curved portion 2412 may be formed on an inclined surface of the front lifter 2410a. The front lifter 2410a according to an embodiment may be formed with a first inclined surface curved portion 2412a and a second inclined surface curved portion 2412b. The first inclined surface curved portion 2412a and the second inclined surface curved portion 2412b reinforce strength of the front lifter 2410a. As an embodiment, it is illustrated that the inclined surface curved portion 2412 is formed in two pieces, but the number thereof may be appropriately increased or decreased depending on a design. An upper end curved portion 2413 may be formed at an upper portion of the front lifter 2410a. The upper end curved portion 2413 reinforces rigidity of the upper portion of the front lifter 2410a. In an embodiment, the upper end curved portion 2413 is formed to have a concave shape at an uppermost end.
[0119] A periphery of the lifter assembly 2410 on the metal plate 41′ forming the cylindrical portion 41 is defined as a lifter periphery A3. The lifter periphery A3 may follow the shape in which the front lifter 2410a protrudes. In the illustrated embodiment, the lifter periphery A3 forming a periphery of the front lifter 2410a is provided. The lifter periphery A3 may mean an area with a predetermined length from a portion where the front lifter 2410a begins to protrude from the reference portion 41a of the metal plate in a direction away from the front lifter 2410a.
[0120] The recess 3415 is defined in the lifter periphery A3. The recess 3415 is defined by processing the metal plate 41′. The recess 3415 is defined by bending the metal plate 41′ forming the cylindrical portion 41. In the illustrated embodiment, the recess 3415 is formed entirely along the lifter periphery A3 and surrounding a periphery of the front lifter 2410a. However, the scope of the claims is not limited to such a drawing. In an embodiment, the recess 3415 may be defined in the lifter periphery A3, but may be defined in at least a portion A3′ between a first position P1, which is a point of the lifter periphery A3, and a second position P2, which is a point located opposite to the first position P1 with respect to a major axis.
[0121] The recess 3415 is also defined around the rear lifter 2410b. A description of the recess 3415 defined around the rear lifter 2410b is replaced with the description of the recess 3415 surrounding the front lifter 2410a. Because stress is concentrated at a portion where the front lifter 2410a and the rear lifter 2410b face each other, it is preferable that the recess 3415 is defined at least at the portion where the stress is concentrated. Therefore, a rear lifter recess defined around the rear lifter 2410b is formed at least in front of the rear lifter periphery, and a front lifter recess defined around the front lifter 2410a is formed at least at the rear of the front lifter periphery.
[0122] The recess 3415 includes a first recess 3415a and a second recess 3415b. The first recess 3415a is defined around the front lifter 2410a. A description of the first recess 3415a may be replaced with the description of the recess 2415 above. The second recess 3415b follows a shape of the first recess 3415a, but has an extended planar shape. The second recess 3415b follows the shape of the first recess 3415a, but is more spaced apart from the front lifter 2410a than the first recess 3415a is.
[0123] According to the illustrated embodiment, the recess 3415 is defined by a recess-defining protrusion 3416. The recess-defining protrusion 3416 includes a first recess-defining protrusion 3416a and a second recess-defining protrusion 3416b. The first recess-defining protrusion 3416a is formed to be spaced apart from the front lifter 2410a by a first distance. A description of the first recess-defining protrusion 3416a may be replaced with the description of the recess-defining protrusion 2416 above. The second recess-defining protrusion 3416b is formed to be spaced apart from the front lifter 2410a by a second distance. The second distance is greater than the first distance. That is, the second recess-defining protrusion 3416b is formed to be more spaced apart from the front lifter 2410a than the first recess-defining protrusion 3416a is. According to an embodiment, the second recess-defining protrusion 3416b surrounds a periphery of the first recess-defining protrusion 3416a. According to an embodiment, the first recess 3415a is defined between the front lifter 2410a and the first recess-defining protrusion 3416a. The second recess 3415b is defined between the first recess-defining protrusion 3416a and the second recess-defining protrusion 3416b. That is, the first recess 3415a is defined by a relationship between the front lifter 2410a and the first recess-defining protrusion 3416a. The second recess 3415b is defined by a relationship between the first recess-defining protrusion 3416a and the second recess-defining protrusion 3416b. As the recess 3415 includes the plurality of recesses as in the embodiment. the stress dispersing effect may be enhanced.
[0124] Unlike the illustrated embodiment, the first recess and the second recess may be defined by protruding outwardly of the cylindrical portion 41 as in the recess shape described in FIGS. 5 to 8.
[0125] In interpreting the scope of the claims with reference to the various embodiments described above, a width of the lifter periphery A1, A2, and A3 is not mathematically defined. The lifter periphery A1, A2, and A3 may be defined by a width of the recess 1415, 2415, and 3415. Based on a vertical level at which the reference portion 41a of the metal plate is located, the portion where the lifter assembly 410 begins to protrude may be defined as the periphery of the lifter assembly 410. The lifter periphery A1, A2, and A3 may be defined as a predetermined area occupied by the position spaced apart from the periphery of the lifter assembly 410 by a predetermined distance. The lifter periphery A1, A2, and A3 may be defined as an area that is defined along the periphery of the lifter assembly 410 and resembles the shape of the periphery of the lifter assembly 410.
[0126] FIG. 20 illustrates agitation of laundry caused by a rotation speed of the drum 40. During a process of rotating the drum 40, forces acting on the laundry within the drum 40 may include gravity, a support force applied from the lifter assembly 410, and a centrifugal force caused by the rotation of the drum 40.
[0127] (a) in FIG. 20 illustrates a case when the drum 40 rotates at a relatively low speed. In this regard, laundry m within the drum 40 is repeatedly subjected to agitation of ascending to a predetermined vertical level by lifter assembly 410 and then descending. Most of the laundry rolls or slides down along the inner circumferential surface of the drum 40 without reaching a vertical level corresponding to a 90-degree rotation in a rotation direction of the drum 40 from the lowest point of the drum 40. Such agitation of the laundry m (e.g., {circle around (1)}→{circle around (2)}→{circle around (3)}) is referred to as ‘rolling’. Further, a rotation of the drum 40 causing the rolling of the laundry m is defined as a ‘rolling motion’. A rotation speed of the drum 40 in the rolling motion may be approximately 30 to 43 rpm.
[0128] (b) in FIG. 20 illustrates a case when the drum 40 rotates at a higher speed than in the case of (a) in FIG. 20. In this regard, most of the laundry m within the drum 40 is repeatedly subjected to agitation of ascending to a vertical level higher than that in the case of rolling (e.g., to a vertical level higher than half a height of the drum 40 or the position corresponding to the 90-degree rotation in the rotation direction of the drum 40 from the lowest point of the drum 40) by the lifter assembly 410 and then descending. Such agitation of the laundry m (e.g., {circle around (1)}→{circle around (2)}→{circle around (3)}→{circle around (4)}) is hereinafter referred to as ‘tumbling’. Further, a rotation of the drum 40 causing the tumbling of the laundry m is defined as a ‘tumbling motion’. A rotation speed of the drum 40 in the tumbling motion is higher than that in the rolling motion, and is, for example, 44 to 48 rpm.
[0129] (c) in FIG. 20 illustrates a case when the drum 40 rotates at a higher speed than in the case of (b) in FIG. 20. When the drum 40 rotates at the high speed, the laundry m continues to rotate without falling even at the highest point of the drum 40 (e.g., {circle around (1)}→{circle around (2)}→{circle around (3)}→{circle around (4)}) in a state of being attached to the inner circumferential surface of the drum 40 by the centrifugal force. A rotation of the drum 40 at this time is defined as a ‘filtration motion’. A rotation speed of the drum 40 in the filtration motion is higher than that in the tumbling motion, and is, for example, 70 rpm or higher.
[0130] FIG. 21 schematically illustrates stress acting on a drum 141 according to an embodiment of the present disclosure and stress distribution at a vulnerable portion. Referring to FIG. 21, a stress distribution structure of the drum 141 according to an embodiment of the present disclosure will be described.
[0131] As an example of the drum 40, the drum 141 is provided. FIG. 21 is an enlarged view of a portion of the drum 141 where the lifter assembly 410 is formed. On the drum 141, the front lifter 410a and the rear lifter 410b are arranged to be misaligned with each other based on a major axis. The rear lifter 410b is formed on a line A-A′. The front lifter 410a is formed on a line B-B′. A cross-sectional view taken along the line A-A′ of the drum 141 where the rear lifter 410b is formed is illustrated and a simulation of a load applied to the corresponding portion is indicated by arrows. The applied load acts in a direction in which the centrifugal force acts. A cross-sectional view taken along the line B-B′ of the drum 141 where the front lifter 410a is formed is illustrated and a simulation of a load applied to the corresponding portion is indicated by arrows. The applied load acts in the direction in which the centrifugal force acts. According to the load simulation, the vulnerable portions where the stress is concentrated are two ends along the major axis of the rear lifter 410b and two ends along the major axis of the front lifter 410a. According to a structure to which a recess 415 according to an embodiment of the present disclosure is applied, the concentrated stress is distributed along a direction of an arrow (--->) , so that the vulnerable portions are improved.
[0132] FIG. 22 schematically illustrates stress acting on a drum 241 according to another embodiment of the present disclosure and stress distribution at a vulnerable portion. Referring to FIG. 22, a stress distribution structure of the drum 241 according to another embodiment of the present disclosure will be described.
[0133] As an example of the drum 40, the drum 241 is provided. FIG. 22 is an enlarged view of a portion of the drum 241 where the lifter assembly 410 is formed. On the drum 241, the front lifter 410a and the rear lifter 410b are arranged coaxially based on a major axis. The front lifter 410a and the rear lifter 410b are formed on a line C-C′. A cross-sectional view taken along the line C-C′ is illustrated and a simulation of a load applied to the corresponding portion is indicated by arrows. The applied load acts in the direction in which the centrifugal force acts. Positions where the highest stress is concentrated on the drum 241 are a rear end along the major axis of the front lifter 410a and a front end along the major axis of the rear lifter 410b. According to the structure to which the recess 415 according to the embodiment of the present disclosure is applied, the concentrated stress is dispersed along the arrow direction, thereby improving the vulnerable portion. According to the embodiment illustrated in FIG. 22 and described with reference thereto, the recess 415 is defined at least at the rear end along the major axis of the front lifter 410a and the front end along the major axis of the rear lifter 410b. These are the vulnerable portions where the stress is most concentrated. According to the structure to which the recess 415 is applied, the concentrated stress is distributed along the direction of the arrow (--->), so that the vulnerable portion is improved.
[0134] The drum 40 is formed by rolling the metal plate 41′ and joining both ends thereof to each other. Because the drum 40 is formed by rolling the metal plate 41′ and joining both ends thereof to each other, a joining line 41e (see FIG. 2) may be formed. When rolling the metal plate 41′, when there is a long horizontal curved shape that is parallel to a rolling direction (a circumferential direction of the drum), there is a risk that the horizontal curved shape may be torn during a manufacturing process. In addition, there is a risk that the horizontal curved shape may be damaged during a use of the drum 40. According to the various embodiments of the present disclosure, compared to forming the horizontal curved shape on a portion lacking rigidity to reinforce the rigidity of the drum 40, the risk of damage during the process of rolling the metal plate 41′ is reduced. In addition, the risk of damage during the use of the drum 40 is reduced.
[0135] The drum 40 is formed by rolling the processed metal plate 41′ and joining both ends thereof to each other. The processed metal plate 41′ is provided with the lifter assembly 410, the recess 415, and the embossing 41b and 41c formed thereon. According to the various embodiments of the present disclosure, the lifter assembly 410 is structurally reinforced, while the risk of tearing during the manufacturing process is reduced, thereby improving the formability.
[0136] The washing machine has been described as the embodiment of the laundry treating apparatus. The drum according to the embodiment of the present disclosure may also be applied to the dryer. When the laundry treating apparatus is the dryer, a heat exchange apparatus that is in communication with the inside of the drum and removes moisture inside the drum may be provided. Furthermore, the drum according to the embodiment of the present disclosure may also be applied to a washer-and-dryer having both functions of the washing machine and the dryer.
[0137] Although the laundry treating apparatus and the method for manufacturing the drum according to the embodiment of the present disclosure have been described as the specific embodiments, these are merely examples, and the present disclosure is not limited thereto and should be interpreted as having the broadest scope according to the basic idea disclosed in the present document. Those skilled in the art may combine or substitute the disclosed embodiments to implement embodiments not specified, but this also does not depart from the scope of the present disclosure. In addition, those skilled in the art may easily change or modify the disclosed embodiments based on the present document, and it is clear that such changes or modifications also fall within the scope of the present disclosure.
Claims
1. A laundry treating apparatus comprising a drum, wherein the drum includes:a cylindrical portion;a lifter assembly formed by protruding inwardly of the cylindrical portion as the cylindrical portion is bent, wherein the lifter assembly has a major axis in a front and rear direction; anda recess defined as the cylindrical portion is bent at a lifter periphery constituting a periphery of the lifter assembly,wherein the recess is defined in at least a portion between a first position, a point at the lifter periphery, and a second position, a point on a side opposite to the first position based on the major axis of the lifter assembly.
2. The laundry treating apparatus of claim 1, wherein the recess is formed by protruding outwardly of the cylindrical portion.
3. The laundry treating apparatus of claim 1, wherein the recess includes:a first recess; anda second recess following a shape of the first recess, wherein the second recess is more spaced apart from the lifter assembly than the first recess is.
4. The laundry treating apparatus of claim 1, wherein the drum further includes a recess-defining protrusion spaced apart from the lifter assembly and formed to protrude inwardly of the cylindrical portion as the cylindrical portion is bent,wherein the recess is defined between the lifter assembly and the recess-defining protrusion.
5. The laundry treating apparatus of claim 4, wherein the recess-defining protrusion includes:a first recess-defining protrusion formed to be spaced apart from the lifter assembly by a first distance; anda second recess-defining protrusion formed to be spaced apart from the lifter assembly by a second distance,wherein the recess includes:a first recess defined between the lifter assembly and the first recess-defining protrusion; anda second recess defined between the first recess-defining protrusion and the second recess-defining protrusion.
6. The laundry treating apparatus of claim 1, wherein the recess is defined throughout the entire lifter periphery.
7. The laundry treating apparatus of claim 1, wherein the cylindrical portion is formed by rolling a metal plate made of a metal material.
8. The laundry treating apparatus of claim 1, wherein the lifter assembly is composed of a plurality of groups, wherein each group is composed of a plurality of lifters,wherein the plurality of groups are arranged equiangularly.
9. The laundry treating apparatus of claim 8, wherein the plurality of lifters constituting each group are arranged to be misaligned with each other with respect to the front and rear direction.
10. The laundry treating apparatus of claim 1, wherein the lifter assembly includes:a plurality of front lifters arranged equiangularly; anda plurality of rear lifters arranged equiangularly and disposed rearward of the front lifters,wherein the recess includes:a front lifter recess defined in a front lifter periphery constituting a periphery of each front lifter; anda rear lifter recess defined in a rear lifter periphery constituting a periphery of each rear lifter.
11. The laundry treating apparatus of claim 10, wherein the front lifter recess is defined at least at the rear of the front lifter periphery.
12. The laundry treating apparatus of claim 10, wherein the rear lifter recess is defined at least in front of the rear lifter periphery.13-14. (canceled)