Clothing processing apparatus and manufacturing method thereof
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- LG ELECTRONICS INC
- Filing Date
- 2026-01-29
- Publication Date
- 2026-08-06
Smart Images
Figure KR2026001749_06082026_PF_FP_ABST
Abstract
Description
Clothing processing device and method of manufacturing the same
[0001] The present invention relates to a clothing processing device and a method for manufacturing the same.
[0002] A clothing processing device applies physical force to clothing to wash and dry it, and includes washing machines, dryers, etc.
[0003] A washing machine separates dirt from a washing object using water and is configured to include a tub for storing water, a drum rotatably provided inside the tub for accommodating a washing object, a water supply unit for supplying water to the tub, and a drainage unit for draining water stored in the tub.
[0004] A dryer removes moisture contained in clothing by providing high-temperature hot air to the items to be washed. It is equipped to simplify its structure by omitting components for supplying or draining water and tubs for storing water, and to improve drying efficiency by supplying hot air directly to the drum.
[0005] In other words, generally, a garment processing device is equipped to process laundry by inserting clothes into a drum and rotating them, thereby utilizing physical friction and the chemical action of detergents.
[0006] The drum may include an internal lifter that lifts and drops the laundry as the drum rotates to change the position of the laundry and help water and detergent penetrate the laundry evenly. When the drum rotates, the lifter is subjected to repetitive loads resulting from the weight of the laundry and the rotational force.
[0007] Therefore, as in the conventional published patent KR 1020120136800, when the lifter is provided to be detachably attached to the drum, the load is concentrated at the joint, causing fatigue stress to accumulate at the joint and resulting in structural weakening. Consequently, cracks may occur at the joint, or problems may arise where the lifter separates from the drum.
[0008] Therefore, a technology for forming a lifter by plastically processing a metal plate that forms a drum, as described in published patent KR 10-2020-0025557, can be applied.
[0009] However, when a lifter is formed by plastically deforming a metal plate that forms a drum as described above, the metal is not smoothly elongated during the press processing of the lifter, causing localized stress concentration, which may result in defects such as fracture or cracking.
[0010] Furthermore, if the elongation length of the metal plate is not sufficiently secured, the protrusion height of the lifter is limited, resulting in a problem where the lifter cannot adequately lift the laundry. This prevents the effective movement and dropping of the laundry, leading to uneven penetration of water and detergent and consequently, a decrease in washing performance.
[0011] In particular, if the lifter does not have a sufficient protrusion height when the drum rotates, the drop distance and impact of the laundry are limited, which reduces physical friction during the washing process. This can further exacerbate problems such as lower washing efficiency, increased washing time, or incomplete soil removal.
[0012] Therefore, technical improvements are required in the process of forming the lifter to enhance the elongation performance of the metal and to stably secure the protrusion height of the lifter.
[0013] The present invention aims to solve the problem of stably integrating a lifter into a drum for molding.
[0014] The present invention aims to solve the problem of preventing local stress concentration and fracture that may occur during the lifter formation process by improving the elongation performance of a metal plate.
[0015] The present invention aims to solve the problem of improving washing performance by stably securing the protrusion height of the lifter.
[0016] The present invention aims to solve the problem of minimizing issues such as breakage or separation even during long-term use by ensuring the structural stability of the lifter.
[0017] The present invention comprises a drum body having a cylindrical shape that rotates about a central axis; and
[0018] A method for manufacturing a drum comprising: a lifter having a truncated cone-shaped protrusion that protrudes toward the central axis of the drum body, wherein a portion of the drum body is formed by pressing; a first drawing process in which a plate-shaped metal plate forming the drum body is press-formed into a first shape in which at least a portion of the area corresponding to the side of the protrusion is stretched; and a second drawing process in which, after the first drawing process, the metal plate is press-formed into a second shape to provide the lifter.
[0019] The first shape above includes a protrusion that protrudes in the form of a closed curve, and the second drawing process can press-form the metal plate such that an inclined portion corresponding to the side of the raised portion overlaps at least a portion with the protrusion.
[0020] The first shape above includes a recessed portion concavely provided on the inner side of the protrusion, and the second drawing process can press-form the metal plate such that the boundary between the upper surface portion corresponding to the upper surface of the raised portion and the inclined portion overlaps with the recessed portion.
[0021] The metal plate can be pressed in the same direction during the first drawing process and the second drawing process to form the first shape and the second shape.
[0022] The length of the first shape protruding from the metal plate may be shorter than the length of the second shape protruding from the metal plate.
[0023] In the second drawing process above, the area where the metal plate is pressed and deformed may be larger than the area where the metal plate is pressed and deformed in the first drawing process above.
[0024] The lifter further includes a recess portion protruding radially along the circumference of the raised portion of the drum body, and the second drawing process can press-form the metal plate such that the boundary of the area that is pressed and deformed in the first drawing process contacts the recess portion.
[0025] The above-mentioned inclined surface may be provided with an inclined curved section in which a part of the inclined surface is formed in a curved manner.
[0026] The above-mentioned protrusions may be provided in the shape of an axisymmetric frustum of an ellipse, in which the cross-sectional area decreases as they protrude toward the central axis of the drum body and the major and minor axes of the bottom and top surfaces overlap each other, and the above-mentioned inclined curves may be provided to avoid the area around the vertex of the major axis.
[0027] The upper portion may include the uppermost region having a closed curve shape; and an upper curved portion that is concavely recessed with respect to the inner surface of the drum body within the uppermost region.
[0028] The first drawing process may include: a first fixing step in which the metal plate is fixed by a first die that fixes the metal plate from the upper side and is equipped with a first holder that fixes the metal plate from the lower side and a mold of the first shape; and a first punching step in which, after the first fixing step, a first punch equipped with the first shape penetrates the first holder and presses the metal plate with the first die to form it.
[0029] The second drawing process may include: a second fixing step in which the metal plate is fixed by a second holder comprising an upper holder that fixes the metal plate from the upper side and a lower holder that fixes the metal plate from the lower side; and a second punching step, after the second fixing step, in which a second punch provided with the second shape penetrates the lower holder and presses the metal plate to form it.
[0030] The second drawing process may further include a pressing step in which, after the second punching step, a mold of the second shape is provided and a second die disposed on the upper part of the metal plate penetrates the upper holder and presses the metal plate in the direction of the second punch to form it.
[0031] The second through hole formed to penetrate the second holder may be provided to be larger than the first through hole formed to penetrate the first holder.
[0032] The second through hole above includes an upper through hole provided in the upper holder and a lower through hole provided in the lower holder, and the upper through hole may be provided larger than the lower through hole.
[0033] The upper through hole may be provided with an area larger than the area where the second shape is projected onto the drum body.
[0034] The lifter may include a boundary forming part formed between the upper through hole and the lower through hole, and having a boundary line formed along the boundary of the upper through hole.
[0035] The boundary forming portion can be extended in the second punching step and provided to be thinner than the thickness of the drum body.
[0036] The above boundary line may be in contact with the drum body to form an angle along the boundary of the upper through hole.
[0037] The lifter further includes a recess portion protruding radially along the circumference of the raised portion of the drum body, and the boundary forming portion has a boundary line formed at one end and a forming line in contact with the recess portion formed at the other end, and the forming line may be provided in a raised shape protruding from the outside to the inside of the drum body.
[0038] The above recess portion is provided with a reference line along the boundary of the first through hole, and the thickness of the inner and outer regions may differ based on the reference line.
[0039] After the second drawing process above, an embossing process may be included in which a portion of the metal plate is press-formed to form an embossing that is indented or protruded relative to the inner surface of the drum body.
[0040] After the second drawing process above, a through-hole process may be included for forming a drum through-hole penetrating the metal plate in the metal plate.
[0041] The above embossing includes a first embossing formed by being recessed with respect to the inner surface of the drum body; and a second embossing formed by being protruded with respect to the inner surface of the drum body; and after the embossing process, a through-hole process can be performed to form a drum through-hole that communicates the inside and outside of the drum body within the first embossing.
[0042] The lifter includes a front lifter positioned at the front and a rear lifter positioned at the rear of the front lifter, wherein the protrusion is provided in the shape of an axisymmetric frustum of an ellipse in which the cross-sectional area decreases as it protrudes toward the central axis of the drum body and the major and minor axes of the bottom and top surfaces overlap each other, and the major axis extends in the front-rear direction of the garment processing device, and the major axis of the front lifter and the major axis of the rear lifter may be provided so as not to overlap each other.
[0043] The present invention can provide a garment processing device in which a lifter is stably integrated into a drum for molding, and a method for manufacturing the same.
[0044] The present invention can provide a garment processing device and a method for manufacturing the same, which improves the elongation performance of a metal plate to prevent local stress concentration and fracture problems that may occur during the lifter formation process.
[0045] The present invention can provide a garment processing device and a method for manufacturing the same, which improves washing performance by stably securing the protrusion height of the lifter.
[0046] The present invention can provide a clothing processing device and a method for manufacturing the same, which ensures the structural stability of the lifter so that problems such as breakage or separation are minimized even during long-term use.
[0047] Figures 1 and 2 illustrate an example of a clothing processing device.
[0048] Figure 3 illustrates an example of a drum.
[0049] Figure 4 illustrates an example of a drum body.
[0050] Figures 5 and 6 illustrate one side of a metal plate forming a drum body.
[0051] Figure 7 illustrates an example of a lifter.
[0052] FIGS. 8, FIGS. 9, and FIGS. 10 illustrate a first embodiment of a lifter.
[0053] FIGS. 11, 12, and 13 illustrate a second embodiment of a lifter.
[0054] FIG. 14 illustrates an example of a first drawing process that is pressed into a first shape.
[0055] FIG. 15 illustrates an example of a second drawing process in which a second shape is formed by pressing.
[0056] FIG. 16 illustrates an example in which a first shape and a second shape are arbitrarily superimposed.
[0057] FIG. 17 shows an exploded view of the mold and metal plate on which the first drawing process is performed.
[0058] FIG. 18 shows an exploded view of the mold and metal plate on which the second drawing process is performed.
[0059] Figure 19 illustrates the process of the first drawing process.
[0060] Figure 20 illustrates the process of the second drawing process.
[0061] Preferred embodiments of the present invention will be described below with reference to the attached drawings. Unless otherwise specifically defined, all terms in this specification shall have the same general meaning as understood by a person skilled in the art to which the present invention pertains. If a term used in this specification conflicts with the general meaning of such term, the definition used in this specification shall prevail.
[0062] As illustrated in FIG. 1, the clothing processing device (100) may be configured to include a cabinet (1), a tub (2) provided inside the cabinet (1) for storing water, and a drum (3) rotatably provided inside the tub (2) for receiving a workpiece.
[0063] The cabinet (1) may be provided to include a front panel (11) forming the front surface of the clothing processing device (100), a rear panel (12) forming the rear surface of the clothing processing device, and a side panel (13) forming the side of the clothing processing device (100).
[0064] The front panel (11) is provided with an input port (111), and the input port (111) may be provided to be openable and closable by a door (112) rotatably fixed to the front panel (11).
[0065] The above front panel (11) may be equipped with an input section (113) and a display section (not shown).
[0066] The input unit (113) is a means for receiving control commands from a user, and the display unit may be provided as a means for displaying control commands selectable by the user and displaying execution information of the control command selected by the user.
[0067] The above clothing processing device (100) may be equipped with a detergent supply device (26) in which a detergent for washing a product to be processed, which will be described later, is stored. The cabinet (1) is equipped with a detergent inlet (114) that communicates with the detergent supply device (26), so that a user can supply detergent to the detergent supply device (26) through the detergent inlet (114).
[0068] The above clothing processing device (100) may be provided with a drainage section (25) through which water stored in the tub (2), which will be described later, is drained. The cabinet (1) may be provided with a drainage filter for filtering foreign substances in the drainage section (25) and an outlet (115) for the extraction and extraction of residual water pipes, etc., for discharging residual water from the drainage section (25).
[0069] FIG. 1 illustrates, as an example, that the detergent inlet (114) and the outlet (115) are provided on the front panel (11).
[0070] As illustrated in FIG. 2, the tub (2) may be provided as a tub body (20) that is provided inside the cabinet (1) and provides a space for storing water. The tub body (20) may be provided as a hollow cylinder, and a tub inlet (21) may be provided on the front of the tub body (20). The tub body (20) may be fixed inside the cabinet (1) through a tub support (22).
[0071] The tub inlet (21) may be provided to be connected to the inlet (111) through a connecting part (25). To prevent water stored inside the tub body (20) from leaking into the cabinet (1), the connecting part (25) may be provided as a cylindrical tube connecting the inlet (111) and the tub inlet (21). Additionally, to prevent vibrations of the tub body (20) from being transmitted to the cabinet (1), the connecting part (25) may be provided with an elastic material such as rubber.
[0072] The drum (3) may be configured to include a drum body (31) that is provided inside the tub body (20) and provides a space for storing clothing.
[0073] The drum body (31) may be provided as a hollow cylinder, and the front of the drum body (31) may be provided with a drum front surface (34) having a drum inlet (341) communicating with the tub inlet (21), and the rear of the drum body (31) may be provided with a drum rear surface (35).
[0074] The drum body (31) above may be provided by processing and forming a metal plate (30).
[0075] The circumferential surface of the drum body (31) may be provided with a drum through hole (32) that communicates the interior of the drum body (31) with the interior of the tub body (20), and a lifter (4) that raises and lowers clothing inside the drum body (31) when the drum body (31) rotates.
[0076] The drum body (31) can be rotatably fixed to the tub body (20) through the driving unit (5).
[0077] The above driving unit (5) may be provided to include a stator (51) fixed to the rear surface of the tub body (20) to form a rotating magnetic field when current is supplied, a rotor (52) located outside the tub body (20) to rotate by the rotating magnetic field, and a rotating shaft (53) that penetrates the rear surface of the tub body (20) and connects to the rear surface of the drum (35).
[0078] The above tub body (20) receives water through the water supply unit (23), and the water stored in the above tub body (20) can be discharged to the outside of the above tub body (20) through the drainage unit (24).
[0079] The above water supply unit (23) may be provided to include a water supply pipe (231) that supplies water by connecting a water source to the tub body (20), and a water supply valve (232) that controls the opening and closing of the water supply pipe (231) according to a control signal from a control unit (not shown).
[0080] The above drainage section (24) may be provided to include a drainage pump (243), a drainage hose (241) connecting the tub body (20) to the drainage pump (243), a drain pipe (244) guiding water discharged from the drainage pump (243) to the outside of the cabinet (1), and a circulation hose (242) circulating water in the tub body (20) through the drainage pump (243).
[0081] The detergent supply device (26) can supply detergent to the tub body (20). The detergent supply device (26) may include a detergent storage unit (262) that provides a space for storing detergent, and a detergent supply pipe (261) that is configured to connect the detergent storage unit (262) and the tub body (20) and guides the detergent discharged from the detergent storage unit (262) to the tub body (20).
[0082] The above water supply pipe (231) may be provided to supply water to the detergent storage unit (262). Accordingly, the detergent storage unit (262) can mix detergent and water and supply them to the tub body (20).
[0083] An example of the above drum (3) is shown in FIG. 3.
[0084] As described above, the drum (3) may include a hollow cylindrical drum body (31) provided inside the tub body (20) and providing a space for storing clothing, a front drum surface (34) provided on the front of the drum body (31) and having a drum inlet (341) communicating with the tub inlet (21), and a rear drum surface (35) provided on the rear of the drum body (31).
[0085] The circumferential surface of the drum body (31) may include the drum through hole (32), a lifter (4) that raises and drops clothing inside the drum body (31) when the drum body (31) rotates, and an embossing (33) that is provided in a shape protruding inwardly or outwardly on the inner circumferential surface of the drum body (31) to disperse the pressure applied to the object to be processed stored in the drum body (31) and improve washing performance.
[0086] The embossing (33) may be provided in a shape that protrudes or is recessed relative to the direction of the central axis (rotation axis) of the drum (3). The embossing (33) may be formed integrally with the drum body (31) and may be provided to have a certain pattern.
[0087] As described below, the embossing (33) is provided in a roughly hemispherical shape, and the drum through-hole (32) may be provided in the center of the embossing (33). Therefore, during the dehydration process, water may be easily drained into the drum through-hole (32) along the curved surface of the embossing (33).
[0088] The lifter (4) may include a front lifter (40a) positioned to face the front of the cabinet (1) relatively and a rear lifter (40b) positioned to face the rear of the cabinet (1) relatively.
[0089] The above front lifter (40a) and the above rear lifter (40b) are provided as a pair, and multiple pairs can be formed at equal angles on the inner circumference of the drum body (31).
[0090] When the lifter (4) is formed by being divided into the front lifter (40a) and the rear lifter (40b) rather than having a shape that extends from the front to the rear, the force generated by the weight and rotational force of the workpiece during the rotation of the drum (3) is divided and distributed to multiple points, thereby preventing damage to the lifter. In addition, since the size of the lifter (4) is reduced, it is easy to mold the lifter (4) integrally with the drum body (31).
[0091] FIG. 3 illustrates a form in which a portion of the metal plate (30) is press-formed to form the lifter (4), and the shape in which the lifter (4) is formed by press-forming from the outer side to the inner side of the drum body (31) is shown. In this case, the connection between parts is eliminated, so durability can be improved.
[0092] The drum body (31) can be formed by plastically deforming the drum through-hole (32), the embossing (33), and the lifter (4) on the plate-shaped metal plate (30) to form them integrally on the metal plate (30), and then welding both ends of the metal plate (30). In this case, a welding line (36) formed by welding both ends of the metal plate (30) can be formed on the drum body (31).
[0093] Figure 4 shows an embodiment of the drum body (31) viewed from the front.
[0094] The front lifter (40a) and the rear lifter (40b) can be formed such that at least a portion does not overlap with respect to the front-rear direction of the cabinet (1), and a pair of the front lifter (40a) and the rear lifter (40b) can be provided at equal angles on the inner surface of the drum body (31). FIG. 4 shows a configuration in which three pairs of the front lifter (40a) and the rear lifter (40b) are provided.
[0095] When the front lifter (40a) and the rear lifter (40b) are arranged so as not to overlap in the front-rear direction, it is easy to maintain balance when the drum (3) rotates, thereby reducing noise, and the washing efficiency can be increased because the washing object is evenly loosened when the drum (3) rotates.
[0096] In addition, when the front lifter (40a) and the rear lifter (40b) are formed by press forming the metal plate (30), the formability can be improved, such as by minimizing the overlap of the areas where the plate is stretched.
[0097] Figures 5 and 6 show one side of the metal plate (30) facing the inner surface of the drum body (31).
[0098] The lifter (4), the drum through hole (32), and the embossing (33) may be integrally formed and provided on the metal plate (30).
[0099] The above embossing (33) may include a first embossing (33a) and a second embossing (33b). The first embossing (33a) and the second embossing (33b) may be provided to protrude in different directions from the drum body (31) with respect to the central axis of the drum body (31).
[0100] The first embossing (33a) can be formed to protrude from the drum body (31) in a direction away from the central axis (outward), and the second embossing (33b) can be formed to protrude from the drum body (31) toward the central axis.
[0101] The above embossing (33) may be provided in a roughly hemispherical shape having a circular cross-section and protruding inward or outward relative to the drum body (31).
[0102] The first embossing (33a) and the second embossing (33b) may be provided with different sizes. For example, they may be provided with different degrees of protrusion and different sizes of maximum cross-sectional areas projected onto the drum body (31).
[0103] In one embodiment of the present invention, the first embossing (33a) may be provided to have a circular plane having a smaller cross-sectional area than the second embossing (33b) with respect to the drum body (31). The second embossing (33b) may be arranged left and right and arranged up and down in an alternating manner. The first embossing (33a) may be placed inside the space surrounded by the second embossing (33b).
[0104] When the first embossing (33a) and the second embossing (33b) are arranged in the pattern described above, the embossing (33) is densely packed with the minimum spacing on the drum body (31), so the function of the embossing (33) can be maximized.
[0105] The drum through hole (32) may be formed in the first embossing (33a). Accordingly, the flow of water discharged into the tub (2) by centripetal force during the dehydration process can be induced by the curved surface of the first embossing (33a).
[0106] The above lifter (4) may be provided by press molding such that a part of the metal plate (30) protrudes in the direction of the central axis of the drum body (31).
[0107] The protruding length of the lifter (4) may be greater than the embossing (33).
[0108] The lifter (4) may be provided to have an elliptical cross-section having a major axis (48) in the front-rear direction of the cabinet (1) relative to the drum body (31). Additionally, a pair of the front lifter (33a) and the rear lifter (33b) may be arranged in the front-rear direction. Accordingly, when the drum (3) rotates, it is easy to induce vertical movement of the object to be processed by the lifter (4).
[0109] The front long axis (48a) of the pair of front lifters (33a) and the rear long axis (48b) of the rear lifter (33b) are arranged so as not to overlap, thereby dispersing the impact caused by collision with the object to be processed and improving washing efficiency. Additionally, when the metal plate (30) and the lifter (4) are formed as a single unit, moldability can be improved.
[0110] The lifter (4) may include an upper portion (43) including the uppermost protruding uppermost region (431) in the direction of the central axis of the drum body (31), a boundary forming portion (46) formed along the circumference of the lifter (4) to form a boundary line (461) at the boundary between the lifter (4) and the drum body (31), and an inclined portion (44) provided to connect the upper portion (43) and the boundary forming portion (46).
[0111] The lifter (4) may include a raised portion (420) comprising an inclined portion (44) that protrudes toward the central axis of the drum body (31) and has a cross-sectional area that becomes smaller as it protrudes, and an upper portion (43).
[0112] The above-mentioned ridge (420) may be provided in a truncated cone shape having a roughly circular upper surface and a bottom surface.
[0113] In one embodiment of the present invention, the raised portion (420) may be provided in the shape of an axisymmetric frustum of an ellipse, in which the cross-sectional area becomes smaller as it protrudes toward the central axis of the drum body (31), and the major and minor axes of the bottom and top surfaces overlap each other.
[0114] The highest protrusion (431) of the upper portion (43) is provided in the form of a closed curve and may include an upper curved portion (432) that is recessed (protrudes in the radial direction of the drum body (31)) opposite to the protrusion direction of the lifter (4). The upper curved portion (432) reinforces the rigidity of the lifter (4) and can prevent deformation caused by collisions due to the load from water and the object to be processed when the drum (3) rotates.
[0115] The above-mentioned inclined portion (44) may be provided as an inclined surface descending from the upper portion (43) toward the boundary forming portion (46), and the inclined portion (44) may be provided with an inclined curved portion (47) protruding from the inclined surface of the inclined portion (44).
[0116] The above-mentioned inclined curved portion (47) may be provided in a shape that protrudes in a raised form from the inclined portion (44) based on the inner surface of the drum body (31).
[0117] The above inclined curved section (47) may be provided in multiple numbers, and the rigidity of the lifter (4) can be reinforced to prevent deformation caused by collisions due to water and loads from the object to be processed when the drum (3) rotates.
[0118] FIG. 7 illustrates an embodiment of the lifter (4) of the present invention. At least a portion of the inclined curve (47) of the lifter (4) may be formed to avoid the periphery of the vertex (481) of the major axis of the lifter (4).
[0119] When the lifter (4) is press-formed onto the metal plate (30), the area around the vertex (481) of the long axis is where deformation of the metal is concentrated. Therefore, if the inclined curve (47) is formed in that area, cracking or fracture of the metal may occur. Thus, if the inclined curve (47) is formed to avoid the area around the vertex (481) of the long axis of the lifter (4), tearing of the metal can be prevented.
[0120] In other words, the inclined curve (47) can be formed around the apex (491) of the short axis (49) of the lifter (4). Since the area of the inclined surface in the direction of the short axis (49) is relatively large and the apex (491) of the short axis (49) of the lifter (4) receives the greatest impact force from the object to be processed and water when the drum (3) rotates, strength and stability can be reinforced by the inclined curve (47).
[0121] The boundary forming part (46) may be extended so that one end contacts the inclined part (44) and the other end contacts the drum body (31). The boundary forming part (46) may be provided with a slope lower than that of the inclined part (44).
[0122] The boundary forming part (46) may be provided to naturally connect the lower part of the lifter (4) to the drum body (31) in a curved shape. The lower part of the lifter (4) is a point where stress caused by water and laundry is concentrated when the drum (3) rotates. Since the boundary forming part (46) disperses the stress concentrated at the lower part of the lifter (4) over a wide area, the possibility of fatigue or cracking of the lifter (4) can be reduced. In addition, when the drum (3) rotates at high speed, the connection between the lifter (4) and the drum body (31) may be prevented from breaking or being locally deformed.
[0123] When the above lifter (4) is formed by press molding on the metal plate (30), the boundary forming part (46) allows the metal plate (30) to flow and stretch naturally, thereby preventing tearing or wrinkles that may occur during the molding process.
[0124] The above boundary line (461) may be provided as a line that separates the boundary between the boundary forming part (46) and the drum body (31).
[0125] The boundary forming part (46) may be a line formed by folding to form an angle with the drum body (31), or it may be a conceptual line dividing the boundary between the drum body (31) and the boundary forming part (46) when the thicknesses of the two parts are different and distinguished.
[0126] FIGS. 8, FIGS. 9, and FIGS. 10 illustrate an embodiment of the lifter (4) of the present invention. The first embodiment of the present invention will be described below with reference to the drawings.
[0127] FIG. 8 shows a cross-sectional view of the short axis (49) of the lifter (4). FIG. 9 shows the lifter (4) viewed radially from the inner circumference of the drum body (31). FIG. 10 shows the surrounding structure based on the boundary forming part (46) of the lifter (4).
[0128] The lifter (4) according to the first embodiment may be formed integrally with the drum body (31). The lifter (4) may be provided in a shape that protrudes toward the central axis of the drum body (31).
[0129] The above lifter (4) may be provided with the raised portion (420) including the upper portion (43) and the inclined portion (44) and the boundary forming portion (46).
[0130] The above lifter (4) may be provided to include a truncated cone-shaped protrusion (420) in which the cross-sectional area is elliptical and becomes smaller as it protrudes.
[0131] The above-mentioned protrusion (420) may be provided in the shape of an axisymmetric frustum of an ellipse, in which the cross-sectional area becomes smaller as it protrudes toward the central axis of the drum body (31), and the major and minor axes of the bottom and top surfaces overlap each other.
[0132] The highest protrusion (431) of the upper part (43) is provided in the form of a closed curve and may include an upper curved part (432) that is recessed (protrudes in the radial direction of the drum body (31)) opposite to the protrusion direction of the lifter (4).
[0133] The upper curved portion (432) may be provided in a shape that is concavely sunken relative to the inner surface of the drum body (31).
[0134] The highest protrusion (431) may be provided in the form of an elliptical tube formed along the perimeter of the upper surface of the raised portion (420). The upper curved portion (432) may be provided in the form of an elliptical shape formed inside the highest protrusion (431).
[0135] The upper bend (432) can reinforce the rigidity of the lifter (4) to prevent deformation caused by collisions due to the load from water and the object to be processed when the drum (3) rotates.
[0136] The highest protrusion (431) is provided in an elliptical tube shape and can be provided in an elliptical shape surrounded by the highest protrusion (431) of the upper curved portion (432).
[0137] The above-mentioned inclined portion (44) may be provided as an inclined surface descending from the upper portion (43) toward the boundary forming portion (46), and the inclined portion (44) may be provided with an inclined curved portion (47) protruding from the inclined surface of the inclined portion (44).
[0138] The above-mentioned inclined curved portion (47) may be provided as an elliptical band along the above-mentioned inclined portion (44), and may be provided in multiple numbers.
[0139] The inclined curved portion (47) of the lifter (4) can be formed to avoid the periphery of the vertex (481) of the long axis of the lifter (4).
[0140] When the above-mentioned inclined curved portion (47) is provided in multiple numbers, some may be provided in an elliptical shape along the inclined portion (44), and the remaining portion may be provided in a straight or curved shape along the periphery of the vertex (491) of the short axis of the inclined portion (44).
[0141] In one embodiment of the present invention, FIGS. 8, 9, and 10 illustrate that one inclined curve (47) is provided on the inclined portion (44) to avoid the periphery of the vertex (481) of the long axis.
[0142] When the lifter (4) is press-formed onto the metal plate (30), the vertex (481) of the long axis is where deformation of the metal is concentrated. Therefore, if the inclined curve (47) is formed in that part, cracking or fracture of the metal may occur. Thus, if the inclined curve (47) is formed to avoid the area around the vertex (481) of the long axis of the lifter (4), tearing of the metal can be prevented.
[0143] In other words, the inclined curve (47) can be formed around the apex (491) of the short axis (49) of the lifter (4). Since the area of the inclined surface in the direction of the short axis (49) is relatively large and the apex (491) of the short axis (49) of the lifter (4) receives the greatest impact force from the object to be processed and water when the drum (3) rotates, strength and stability can be reinforced by the inclined curve (47).
[0144] The boundary forming part (46) can be extended so that one end contacts the inclined part (44) and the other end contacts the drum body (31).
[0145] When the lifter (4) is formed by press molding the metal plate (30) into a second shape (42) to be described later, which is a shape excluding the boundary forming part (46), the surrounding area of the second shape (42) is indirectly stretched and the area can form the boundary forming part (46).
[0146] In the case of the above-described embodiment, the second shape (42) may be provided as the raised portion (420).
[0147] The boundary forming part (46) may be provided with a slope lower than that of the slope part (44), and the thickness (D46) of the boundary forming part may be provided to be thinner than the thickness (D30) of the drum body.
[0148] In one embodiment of the present invention, the boundary forming portion (46) is illustrated as being inclined in a direction that protrudes toward the central axis of the drum body (31) toward the inclined portion (44) with respect to the boundary line (461). The inclination direction or shape of the boundary forming portion (46) may vary depending on the elastic modulus, elongation, yield strength, thickness, etc. of the metal plate (30), and may be inclined to protrude toward the radial direction of the drum body (31), or may be provided to be concave or convex relative to the inner surface of the drum body (31) due to the uneven distribution of stress, etc.
[0149] One end of the boundary forming part (46) may have the boundary line (461) formed, and the other end may have a forming line formed. In the first embodiment illustrated in FIGS. 8, 9, and 10, the forming line may be formed between the raised part (420) and the boundary forming part (46), and this is defined as the first forming line (441).
[0150] The boundary forming part (46) and the slope part (44) come into contact with the first molding line (441), and can be distinguished by the change in slope of the first molding line (441).
[0151] The raised portion (420) corresponding to the second shape (42) that is press-formed on the metal plate (30) is stretched more than the boundary forming portion (46) that is indirectly stretched, so the thickness (D42) of the raised portion can be thinner than the thickness (D30) of the boundary forming portion.
[0152] FIGS. 11, 12, and 13 illustrate a second embodiment of the lifter (4) of the present invention. The second embodiment of the present invention will be explained below through the drawings.
[0153] FIG. 11 shows a cross-sectional view of the short axis (49) of the lifter (4). FIG. 12 shows the lifter (4) viewed radially from the inner circumference of the drum body (31). FIG. 13 shows the surrounding structure based on the boundary forming part (46) of the lifter (4).
[0154] The lifter (4) according to the second embodiment may be formed integrally with the drum body (31). The lifter (4) may include a shape including the raised portion (420) protruding toward the central axis of the drum body (31).
[0155] The lifter (4) may be provided to include the raised portion (420) comprising the upper portion (43) and the inclined portion (44), the boundary forming portion (46), and the recess portion (45) protruding radially from the drum body (31) between the boundary forming portion (46) and the raised portion (420).
[0156] The above recess portion (45) may be provided to include a descending portion (451) extending in a direction inclined toward the drum body (31) from the inclined portion (44), and an ascending portion (453) extending in a direction inclined toward the central axis of the drum body (31) from the bottom portion (452) which protrudes most protrudingly in the radial direction of the drum body (31) and contacting the boundary forming portion (46).
[0157] The bottom portion (452) may be provided closer to the central axis direction of the drum body (31) than the drum body (31).
[0158] The above recess (45) can relieve the concentration of stress applied to the boundary between the inclined portion (44) and the drum body (30) by clothing and water when the drum body (31) rotates.
[0159] The above recess portion (45) may be provided in a tubular shape having an inner diameter and an outer diameter that surrounds the above-mentioned protrusion (420). The above-mentioned recess portion (45) may include a reference line (414) in the shape of a closed curve, which will be described later, between the inner diameter and the outer diameter.
[0160] The thickness of the inner region and the outer region of the above recess (45) may differ based on the reference line (414).
[0161] The above recess (45) can be made such that the inner region and the outer region form an angle with respect to the above reference line (414).
[0162] The above-mentioned protrusion (420) may be provided in the shape of an axisymmetric frustum of an ellipse, in which the cross-sectional area becomes smaller as it protrudes toward the central axis of the drum body (31), and the major and minor axes of the bottom and top surfaces overlap each other.
[0163] The highest protrusion (431) of the upper part (43) is provided in the form of a closed curve and may include an upper curved part (432) that is recessed (protrudes in the radial direction of the drum body (31)) opposite to the protrusion direction of the lifter (4).
[0164] The upper curved portion (432) may be provided in a shape that is concavely sunken relative to the inner surface of the drum body (31).
[0165] The highest protrusion (431) may be provided in the form of an elliptical tube formed along the perimeter of the upper surface of the raised portion (420). The upper curved portion (432) may be provided in the form of an elliptical shape formed inside the highest protrusion (431).
[0166] The upper bend (432) can reinforce the rigidity of the lifter (4) to prevent deformation caused by collisions due to the load from water and the object to be processed when the drum (3) rotates.
[0167] The highest protrusion (431) is provided in an elliptical tube shape and can be provided in an elliptical shape surrounded by the highest protrusion (431) of the upper curved portion (432).
[0168] The above-mentioned inclined portion (44) may be provided as an inclined surface descending from the upper portion (43) toward the boundary forming portion (46), and the inclined portion (44) may be provided with an inclined curved portion (47) protruding from the inclined surface of the inclined portion (44).
[0169] The inclined curved portion (47) of the lifter (4) can be formed to avoid the periphery of the vertex (481) of the long axis of the lifter (4).
[0170] When the lifter (4) is press-formed onto the metal plate (30), the vertex (481) of the long axis is where deformation of the metal is concentrated. Therefore, if the inclined curve (47) is formed in that part, cracking or fracture of the metal may occur. Thus, if the inclined curve (47) is formed to avoid the area around the vertex (481) of the long axis of the lifter (4), tearing of the metal can be prevented.
[0171] In other words, the inclined curve (47) can be formed around the apex (491) of the short axis (49) of the lifter (4). Since the area of the inclined surface in the direction of the short axis (49) is relatively large and the apex (491) of the short axis (49) of the lifter (4) receives the greatest impact force from the object to be processed and water when the drum (3) rotates, strength and stability can be reinforced by the inclined curve (47).
[0172] The boundary forming part (46) can be extended so that one end contacts the recess part (45) and the other end contacts the drum body (31).
[0173] When the lifter (4) is formed by press molding the metal plate (30) into a second shape (42) to be described later, which is a shape excluding the boundary forming part (46), the surrounding area of the second shape (42) is indirectly stretched and the area can form the boundary forming part (46). Accordingly, the thickness (D46) of the boundary forming part can be provided to be thinner than the thickness (D30) of the drum body.
[0174] In the case of the second embodiment described above, the second shape (42) may be provided with the raised portion (420) and the recess portion (45).
[0175] One end of the boundary forming part (46) may have the boundary line (461) formed therein, and the other end may have a forming line formed therein. In the second embodiment illustrated in FIGS. 11, 12, and 13, the forming line may be formed between the recess part (45) and the boundary forming part (46), and this is defined as the second forming line (451).
[0176] The boundary forming part (46) may be provided in a shape that extends obliquely from the rising part (453) of the recess part (45) toward the drum body (31).
[0177] With respect to the second molding line (451), the boundary forming part (46) and the rising part (453) come into contact, and the first molding line (441) can be formed by the rising part (453) and the boundary forming part (46) with respect to the inner surface of the drum body (31). That is, the second molding line (451) can be provided in a raised shape formed from the outside to the inside of the drum body (31) with respect to the inner circumference of the drum body (31).
[0178] The raised portion (420) and the recess portion (45) corresponding to the second shape (42) that is press-formed on the metal plate (30) are stretched more than the boundary forming portion (46) that is indirectly stretched, so the thickness (D42) of the second shape can be provided thinner than the thickness (D30) of the boundary forming portion.
[0179] The lifter (4) is formed by pressing a portion of the metal plate (30) forming the drum body (31), and can be provided through a first drawing process (S10) in which it is press-formed into a first shape (41) shown in FIG. 14, followed by a second drawing process (S20) in which it is press-formed into a second shape (42) shown in FIG. 15. FIG. 16 shows the first shape (41) and the second shape (42) superimposed.
[0180] Hereinafter, the first drawing process (S10) and the second drawing process (S20) are explained through FIGS. 14, 15, and 16.
[0181] The lifter (4) may be provided to include the truncated cone-shaped protrusion (420) that protrudes toward the central axis of the drum body (31).
[0182] The corner portion where the upper surface portion (43) and the inclined portion (44) of the raised portion (420) meet is a point where the curvature changes abruptly, and stress is concentrated therein. As a result, the metal may not flow to be sufficiently stretched, leading to local fracture or necking phenomena. Therefore, the first drawing process (S10) can press-form the plate-shaped metal plate (S30) into a first shape (41) that stretches at least a portion of the area corresponding to the inclined portion (44).
[0183] The inclined portion (44) is the maximum tensile deformation section where the metal plate (30) is stretched the most. When the area corresponding to the inclined portion (44) is stretched first, plastic deformation proceeds in the metal in the area corresponding to the inclined portion (44). Therefore, when additional forming is performed thereafter, there is a plastic deformation margin capable of withstanding additional deformation. In addition, since stress is evenly distributed in the metal material and the flow of the material becomes smooth, the defect rate caused by fracture at the boundary between the inclined portion (44) and the upper portion (43) during the subsequent second drawing process (S20) can be minimized.
[0184] In addition, when the metal is plastically deformed step by step through the first drawing process (S10), the stress applied by press forming is dispersed, so the metal is evenly elongated, and thus the stress is not concentrated in specific parts, so the variation in the thickness reduction rate of each section of the lifter (4) can be reduced.
[0185] Figure 14 illustrates an example in which the first drawing process (S10) is performed to press-form the metal plate (30) into the first shape (41).
[0186] The first shape (41) may be provided to include a protrusion (412) that protrudes in the form of a closed curve, and a depression (411) that is concavely provided inside the protrusion.
[0187] The above-mentioned recess (411) may be provided to protrude from the metal plate (30) in the direction of the protrusion (411).
[0188] The outer side of the protrusion (412) is provided to be inclined toward the metal plate (30), and the portion where the boundary between the first shape (41) and the metal plate (30) is formed includes a transition portion (413) provided such that the angle is gradually reduced.
[0189] The above-mentioned transition part (413) can subsequently be stretched in advance to the part corresponding to the lower corner of the above-mentioned protrusion (420) to prevent defects such as breakage.
[0190] The protrusion (412) forms a slope leading to the depression (411) and the transition portion (413), so the metal plate (30) can be stretched most significantly in the first drawing process (S10).
[0191] Figure 15 illustrates an example in which the second drawing process (S20) is performed to provide the lifter (4) by press-forming the metal plate (30) into the second shape (42) after the first drawing process (S10).
[0192] As described above, the second shape (42) may be provided with the raised portion (420) in the case of the first embodiment, and may be provided with the raised portion (420) and the recess portion (45) in the case of the second embodiment.
[0193] The raised portion (420) constituting the second shape (42) may include the upper portion (43) and the inclined portion (44).
[0194] The upper portion (43) may be provided with the highest protrusion (431) and the upper curve (432).
[0195] The above-mentioned inclined portion (44) may include the above-mentioned inclined curved portion (47).
[0196] The above second drawing process (S20) can press-form the metal plate such that the inclined portion (44) overlaps at least a portion with the protrusion (412).
[0197] The above inclined section (44) is the maximum tensile deformation section where the metal plate (30) is stretched the most. When it is stretched in advance due to the protrusion (412), stress is evenly distributed in the metal material, and the flow of the material becomes smooth. Therefore, during the subsequent second drawing process (S20), the defect rate caused by fracture at the boundary between the inclined section (44) and the upper section (43) is minimized, and stress is not concentrated in a specific area, so the deviation in the thickness reduction rate of each section of the lifter (4) can be reduced.
[0198] The above second drawing process (S20) can press-form the metal plate (30) such that the boundary between the upper surface (43) and the inclined portion (44) overlaps with the recessed portion (411).
[0199] The boundary between the inclined portion (44) and the upper surface portion (43) is provided to overlap with the protrusion (412) at the corner portion where stress is concentrated. If excessive elongation occurs, excessive plastic deformation may cause necking or distortion, which may reduce the durability of the lifter (4). Therefore, if the corner of the raised portion (420) is positioned at the recessed portion (411) which is elongated relatively less to allow for plastic deformation, structural stability and molding reliability can be improved.
[0200] In one embodiment of the present invention, the metal plate (30) may be pressed in the same direction in the first drawing process (S10) and the second drawing process (S20) to form the first shape (41) and the second shape (42).
[0201] Conversely, the metal plate (30) may be pressed in different directions during the first drawing process (S10) and the second drawing process (S20) to form the first shape (41) and the second shape (42).
[0202] FIG. 16 illustrates the first shape (41) and the second shape (42) superimposed.
[0203] The height at which the first shape (41) protrudes from the metal plate (30) is lower than the height at which the second shape (42) protrudes from the metal plate (30), so that unnecessary elongation of the metal plate (30) can be prevented.
[0204] In the second drawing process (S20), the area where the metal plate (30) is pressed and deformed (the area projected onto the metal plate (30)) may be larger than the area where the metal plate (30) is pressed and deformed (the area projected onto the metal plate (30)) in the first drawing process (S10). Accordingly, the reference line (414) formed by the boundary of the mold during the first drawing process (S10) may be blurred or hidden by the second drawing process (S20), thereby improving appearance and durability.
[0205] The above reference line (414) may be provided in contact with the drum body (30) and the first shape (41) so as to form an angle.
[0206] The second drawing process (S20) above can press-form the metal plate so that the boundary of the area deformed by pressing in the first drawing process (S10) comes into contact with the recess portion (45). Thus, the reference line (414) can be easily hidden within the curvature of the recess portion (45).
[0207] Based on the reference line (414), the inner side is stretched twice through the first drawing process (S10) and the second drawing process (S20), and the outer side is stretched only through the second drawing process (S20), so the thickness can be provided differently based on the reference line (414).
[0208] The above recess portion (45) is provided so as to overlap at least a portion with the above transition portion (413), and thus formability and durability can be improved through pre-stretching.
[0209] FIG. 17 illustrates the appearance of the mold part (6) and the metal plate (30) that perform the first drawing process (S10).
[0210] The mold part (6) of the first drawing process (S10) may be provided to include a first holder (61) that fixes the metal plate (30) from the lower side, a first die (62) that fixes the metal plate (30) from the upper side and is equipped with a frame of the first shape (410), and a first punch (63) that is provided with the first shape (41) and presses the metal plate (30) with the first die (62) to form it.
[0211] The first holder (61) may include a first through hole (611) through which the first punch (63) passes and which defines a forming area of the metal plate (30).
[0212] FIG. 18 illustrates the appearance of the mold part (6) and the metal plate (30) performing the second drawing process (S20).
[0213] The mold part (6) performing the second drawing process (S20) may be provided to include a second holder (64) comprising an upper holder (65) that fixes the metal plate (30) from the upper side and a lower holder (66) that fixes the metal plate from the lower side, a second punch (68) that presses and forms the metal plate (30) into the second shape (42), and a second die (67) that is equipped with a frame of the second shape (42) and presses and forms it in the direction of the second punch (68).
[0214] The second holder (64) may be provided to include a second through hole (641) comprising a lower through hole (661) provided in the lower holder (66) through which the second punch (68) passes and which defines a forming area of the metal plate (30), and an upper through hole (651) provided in the upper holder (65) and which defines an elongation area of the metal plate (30).
[0215] Figure 19 illustrates an example of the first drawing process (S10) described above.
[0216] The first drawing process (S10) may include a first fixing step (S11) in which the metal plate (30) is fixed by the first die (62) which fixes the metal plate (30) from the upper side and is equipped with the first holder (61) which fixes the metal plate (30) from the lower side and the frame of the first shape (41); and a first punching step (S12) in which, after the first fixing step (S11), the first punch (63) which is equipped with the first shape (41) penetrates the first through hole (611) of the first holder (61) and presses the metal plate (30) with the first die (62) to form it. An example of the first fixing step (S11) is illustrated in FIG. 19(a), and an example of the first punching step (S12) is illustrated in FIG. 19(b).
[0217] In the first drawing process (S10) above, the portion where the metal plate (30) is stretched to form the first shape (41) may be the area corresponding to the first through hole (611). Accordingly, the area where the first punch (63) is inserted into the first die (62) and the area projected onto the metal plate (30) may be the same size as the first through hole (611). The area projected in the direction in which the first punch (63) is inserted into the metal plate (30) may be the same size as the first through hole (611).
[0218] Since the metal plate (30) corresponding to the area of the first through hole (611) is extended, the thickness may differ at the boundary of the first through hole (611), and the boundary of the first through hole (611) may form the reference line (414). Accordingly, the inner area may be provided thinner than the outer area based on the reference line (414), or the metal plate (30) may be provided to be folded inward toward the drum body (30) at the boundary of the reference line (414).
[0219] Figure 20 illustrates an example of the second drawing process (S20) described above.
[0220] The second drawing process (S20) above may include a second fixing step (S21) in which the metal plate is fixed by the second holder (64), which includes the upper holder (65) that fixes the metal plate (30) from the upper side as shown in FIG. 20(a) and the lower holder (66) that fixes the metal plate (30) from the lower side.
[0221] After the second fixing step (S21), the method may include a second punching step (S22) in which the second punch (68), which is provided with the second shape (42), penetrates the lower holder (66) and presses the metal plate (30) to form it.
[0222] After the second punching step (S22), the method may include a pressing step (S23) in which the second die (67), which is positioned on the upper part of the metal plate (30) and has a mold of the second shape (42) provided therein, penetrates the upper holder (65) and presses the metal plate (30) in the direction of the second punch (68) to form it.
[0223] When press forming in the second punching step (S22), the deformation starts from the center of the lifter (4) (the recessed part (411) of the first shape (41)), thereby inducing a uniform distribution of internal stress and establishing a flow path for the metal. Therefore, when the pressing step (S23) is subsequently performed, the metal flows naturally along the wall of the second die (67) when forming by pressing from the upper side to the lower side, the elongation distribution becomes uniform, and plastic deformation can occur relatively uniformly. That is, when the pressing step (S23) is performed after the second punching step (S22), the uniformity of the elongation can be optimized.
[0224] In the above punching step (S22), the boundary between the recess (411) and the protrusion (412) may be extended. The upper portion (43) of the second shape (42) may be formed in the recess (411).
[0225] When the corners of the inclined portion (44) and the upper portion (43) are positioned at the boundary between the indented portion (411) and the protruding portion (412), the elongation of the corners of the inclined portion (44) and the upper portion (43) is induced most significantly during the second punching step (S22), and the stress is dispersed to the surroundings, so that the stress is concentrated on the corners of the inclined portion (44) and the upper portion (43) during the subsequent pressing step (S23), thereby minimizing defects such as necking.
[0226] The second through hole (641) formed to penetrate the second holder (64) may be larger than the first through hole (611) formed to penetrate the first holder (61). Accordingly, the reference line (414) formed along the first through hole (611) is press-formed and deformed again in the second drawing process (S20), so the difference in physical properties (thickness, stress, etc.) between the inner and outer sides of the reference line (414) is mitigated, and the folding angle formed by the reference line (414) is mitigated, thereby improving the aesthetics and durability of the lifter (4).
[0227] The upper through hole (651) may be larger than the lower through hole (661).
[0228] The upper through hole (651) can define an area into which the second punch (68) is inserted and stretched in the second punching step (S22), and the lower through hole (661) can define an area into which the second die (67) and the second punch (68) are stretched in the compression step (S23).
[0229] The area where the second shape (42) is projected onto the metal plate (30) may be the same as the size of the lower through hole (661). That is, the size of the upper through hole (651) may be larger than the area where the second shape (42) is projected onto the drum body (31).
[0230] The second punch (68) above may be provided with the second shape (42).
[0231] When the second punching step (S22) is performed, the area between the lower through hole (661) and the upper through hole (651) can be stretched along the second punch (68). In this case, since the metal is stretched in an area larger than the area where the second shape (42) is projected onto the drum body (31), the stress is distributed over a wider area of the metal, thereby preventing local fracture or excessive reduction in thickness.
[0232] A boundary forming portion (46) may be formed in the area between the upper through hole (651) and the lower through hole (661). Based on the boundary forming portion (46), the inner side undergoes two elongations through the second punching step (S22) and the compression step (S23), while the outer side undergoes only indirect elongation during the second punching step (S22). Therefore, the thickness may be provided differently based on the boundary forming portion (46).
[0233] The boundary forming part (46) is folded so as to protrude inwardly from the drum body (31) in the second punching step (S22), and the boundary line (461) can form a folding angle.
[0234] The area of the second die (67) projected onto the metal plate (30) can be provided with the size of the upper through hole (651). Accordingly, the boundary forming part (46) can be pressed downward during the pressing step (S23) after the second punching step (S22). In this case, it can spring back due to the elastic restoring force of the already deformed boundary forming part (46). The angle of inclination of the springbacked boundary forming part (46) and the folding angle of the boundary line (4661) can be made gentler.
[0235] The boundary forming part (46) may have the boundary line (461) formed at one end and the forming line (441, 451) formed at the other end.
[0236] The above-mentioned forming lines (441, 451) may be formed along the boundary of the lower through hole (661). The above-mentioned forming lines (441, 451) may be formed by the second die (67) and the second punch (68) being joined together in the pressing step (S23).
[0237] Based on the above-mentioned forming lines (441, 451), the inner region undergoes two elongations through the second punching step (S22) and the pressing step (S23), while the outer region undergoes only indirect elongation in the second punching step (S22). Therefore, the thickness can be provided differently based on the boundary forming part (46).
[0238] In the first embodiment of the present invention, in which the lifter (4) is provided as the raised portion (420), the boundary forming portion (46) may have the boundary line (461) formed at one end and the first forming line (441) in contact with the inclined portion (44) formed at the other end.
[0239] The first molding line (441) may be formed at the boundary between the boundary forming part (46) and the inclined part (44) such that the angle of inclination changes.
[0240] In the second embodiment of the present invention, in which the lifter (4) includes the raised portion (420) and the recess portion (45), the boundary forming portion (46) may have the boundary line (461) formed at one end and the second forming line (451) in contact with the recess portion (45) formed at the other end.
[0241] Since the second forming line (451) is inclined in opposite directions relative to one side of the metal plate (30) (the inner surface of the drum body (31)), the second forming line (451) can be provided in a raised shape protruding from the outside to the inside of the drum body (31).
[0242] The above reference line (414) may be provided to overlap with the above recess (45).
[0243] Accordingly, since the recess portion (45) partially overlaps the stretched portion of the transition portion (413), stress concentration is alleviated, and when the reference line (414) appears on the exterior, it is hidden by the curvature of the recess portion (45), so aesthetics can be enhanced.
[0244] In an exemplary embodiment of the present invention, when the reference line (414) is positioned on the rising portion (454), stress concentration during the elongation of the recess portion (45) is minimized and exposure of the reference line (414) can be minimized.
[0245] After the second drawing process (S20) above, an embossing process may be performed to press-form the embossing (33) in which a part of the metal plate (30) is sunken or protrudes relative to the inner surface of the drum body (31).
[0246] Since the lifter (4) requires a large amount of elongation when pressed compared to the embossing (33), if the lifter (4) is formed first, the deformation or warping of the embossing (33) can be reduced.
[0247] After the second drawing process (S20) above, a through-hole process may be performed to form the drum through-hole (32) that penetrates the metal plate (30) in the metal plate (30).
[0248] When the drum through hole (32) is formed after the second drawing process (S20), the deformation of the drum through hole (32) due to the stretching of the metal can be prevented.
[0249] After the above embossing process, the through-hole process of forming the drum through-hole (32) inside the first embossing (33a) can be performed.
[0250] When the drum through-hole (32) is formed after the press process of forming the embossing (33), positional errors caused by elastic restoring force or deformation occurring during the forming process are prevented, and deformation of the drum through-hole (32) can be prevented. Therefore, during the dehydration process, water can be efficiently discharged along the curvature of the first embossing (33a) by centripetal force, and uniform drum through-hole (32) can be formed, thereby increasing aesthetic appeal.
[0251] After the first drawing process (S10), the second drawing process (S20), the embossing process, and the through-hole process are all performed on the metal plate (30), the metal plate (30) is rolled into the shape of the drum body (31), and then both ends are welded to produce the drum body (31).
[0252] Although the present invention has been illustrated and described in relation to specific embodiments, it will be obvious to those skilled in the art that the present invention can be modified and changed in various ways without departing from the technical spirit of the invention as provided by the following claims.
Claims
1. A drum body provided in a cylindrical shape that rotates about a central axis; and A method for manufacturing a drum comprising: a lifter having a truncated cone-shaped protrusion protruding toward the central axis of the drum body, wherein a portion of the drum body is formed by compression, and the lifter is provided with such a protrusion. A first drawing process for press-forming a plate-shaped metal plate forming the drum body into a first shape in which at least a portion of the area corresponding to the side of the ridge is stretched; and A method for manufacturing a drum characterized by including: a second drawing process, wherein, after the first drawing process, the metal plate is press-formed into a second shape to provide the lifter.
2. In Paragraph 1, The first shape above includes a protrusion that protrudes in the form of a closed curve, and A method for manufacturing a drum, characterized in that the second drawing process above press-forms the metal plate such that the inclined portion corresponding to the side of the raised portion overlaps at least a portion of the protrusion.
3. In Paragraph 2, The first shape above includes a recessed portion concavely provided on the inner side of the protrusion, and A method for manufacturing a drum, characterized in that the second drawing process above press-forms the metal plate such that the boundary between the upper surface corresponding to the upper surface of the raised portion and the inclined portion overlaps with the recessed portion.
4. In Paragraph 1, A method for manufacturing a drum characterized in that the metal plate is pressed in the same direction during the first drawing process and the second drawing process to form the first shape and the second shape.
5. In Paragraph 1, A method for manufacturing a drum characterized in that the length of the first shape protruding from the metal plate is shorter than the length of the second shape protruding from the metal plate.
6. In Paragraph 1, A method for manufacturing a drum, characterized in that the area where the metal plate is pressed and deformed in the second drawing process is larger than the area where the metal plate is pressed and deformed in the first drawing process.
7. In Paragraph 1, The lifter further includes a recess portion protruding radially along the circumference of the raised portion of the drum body, and A method for manufacturing a drum, characterized in that the second drawing process above press-forms the metal plate such that the boundary of the area deformed by pressing in the first drawing process contacts the recess.
8. In Paragraph 2, A method for manufacturing a drum characterized by the above-mentioned inclined surface having an inclined curved portion formed such that a part of the inclined surface is curved.
9. In Paragraph 8, The above-mentioned protrusion is provided in the shape of an axisymmetric frustum of an ellipse, in which the cross-sectional area decreases as it protrudes toward the central axis of the drum body, and the major and minor axes of the bottom and top surfaces overlap each other. A method for manufacturing a drum characterized in that the above-mentioned inclined curved portion is provided to avoid the periphery of the vertex of the above-mentioned major axis.
10. In Paragraph 3, The upper part mentioned above is, The uppermost region of the closed curve shape; and A method for manufacturing a drum characterized by including an upper curved portion that is concavely sunken with respect to the inner surface of the drum body within the uppermost region.
11. In Paragraph 1, The above first drawing process is, A first fixing step in which the metal plate is fixed by a first holder that fixes the metal plate from the lower side and a first die that fixes the metal plate from the upper side, wherein the metal plate is fixed by a first die that fixes the metal plate from the upper side and is provided with a mold of the first shape; and A method for manufacturing a drum, characterized by including: a first punching step in which, after the first fixing step, a first punch provided in the first shape penetrates the first holder and presses the metal plate with the first die to form it.
12. In Paragraph 1, The above second drawing process is, A second fixing step in which the metal plate is fixed by a second holder comprising an upper holder that fixes the metal plate from the upper side and a lower holder that fixes the metal plate from the lower side; and A method for manufacturing a drum, characterized by including: a second punching step in which, after the second fixing step, a second punch provided in the second shape penetrates the lower holder and presses the metal plate to form it.
13. In Paragraph 12, The above second drawing process is, A method for manufacturing a drum, further comprising: a pressing step in which, after the second punching step, a mold of the second shape is provided and a second die disposed on the upper part of the metal plate penetrates the upper holder and presses the metal plate in the direction of the second punch to form it.
14. In Paragraph 13, A method for manufacturing a drum characterized in that a second through hole formed to penetrate the second holder is larger than a first through hole formed to penetrate the first holder.
15. In Paragraph 14, The second through hole above includes an upper through hole provided in the upper holder and a lower through hole provided in the lower holder, and A method for manufacturing a drum characterized in that the upper through hole is provided to be larger than the lower through hole.
16. In Paragraph 15, A method for manufacturing a drum, characterized in that the upper through hole is provided with an area larger than the area where the second shape is projected onto the drum body.
17. In Paragraph 16, A method for manufacturing a drum, characterized in that the lifter comprises a boundary forming portion formed between the upper through hole and the lower through hole, and having a boundary line formed along the boundary of the upper through hole.
18. In Paragraph 17, A method for manufacturing a drum characterized in that the boundary forming portion is stretched in the second punching step and provided to be thinner than the thickness of the drum body.
19. In Paragraph 17, A method for manufacturing a drum characterized by the above boundary line contacting the drum body to form an angle along the boundary of the upper through hole.
20. In Paragraph 17, The lifter further includes a recess portion protruding radially along the circumference of the raised portion of the drum body, and The above boundary forming part has the boundary line formed at one end and the molding line in contact with the recess part formed at the other end, A method for manufacturing a drum, characterized in that the above-mentioned molding line is provided in a raised shape protruding from the outer side to the inner side of the drum body.
21. In Paragraph 20, The above recess portion is provided with a reference line along the boundary of the first through hole, and A method for manufacturing a drum characterized by having different thicknesses in the inner and outer regions based on the above reference line.
22. In Paragraph 1, A method for manufacturing a drum comprising: an embossing process in which, after the second drawing process, a portion of the metal plate is press-molded to form an embossing that is indented or protruded relative to the inner surface of the drum body.
23. In Paragraph 1, A method for manufacturing a drum comprising: a through-hole process for forming a drum through-hole penetrating the metal plate in the metal plate after the second drawing process above.
24. In Paragraph 22, The above embossing is, A first embossing formed by being recessed based on the inner surface of the drum body; and It includes a second embossing formed by protruding based on the inner surface of the drum body; A method for manufacturing a drum, characterized by performing a through-hole process after the above embossing process, wherein a drum through-hole is formed within the first embossing to communicate the inside and outside of the drum body.
25. In Paragraph 1, The above lifter includes a front lifter positioned at the front and a rear lifter positioned at the rear of the front lifter. The above-mentioned protrusion is provided in the shape of an axisymmetric frustum of an ellipse, in which the cross-sectional area decreases as it protrudes toward the central axis of the drum body, and the major and minor axes of the bottom and top surfaces overlap each other. The above long axis extends in the front-rear direction of the clothing processing device, and A method for manufacturing a drum characterized by the fact that the long axis of the front lifter and the long axis of the rear lifter are provided so as not to overlap each other.