KR20050079676A - Method for forming drum for dryer and structure of drum fabricating by thereof - Google Patents

Abstract

The present invention improves the workability during manufacture by manufacturing the drum integrally by improving the molding method of the drum for the dryer and to improve the overall roundness of the drum to improve the reliability of the dryer by reducing vibration and noise when the product is applied. In addition, to provide a drum of an optimized structure suitable for the expansion molding method.

To this end, the present invention comprises the steps of forming a cylindrical drum; Expanding a portion excluding both ends of the cylindrical drum; Processing the beads in the expansion portion of the cylindrical drum; The drum forming method for a dryer is provided, comprising the step of: performing a bending hemming process by bending both edges of the cylindrical drum to overlap.

On the other hand, the present invention is a cylindrical body having a joint portion joined by butt welding to a portion of the metal material abutting each other; Openings provided at both ends of the body part to have a diameter smaller than that of the body part; A bead portion formed to reinforce strength in the body portion; It is provided with a dryer drum, characterized in that it comprises a hemming portion that is hemmed so that the edges of the opening overlap.

Description

Method for forming drum for dryer and structure of drum fabricating by

The present invention relates to a dryer drum, and more particularly, to an improvement in the molding method of the drum mounted on the clothes dryer and to a structure of the drum accordingly.

Background Art In general, a dryer is a device for supplying hot air generated by an electric heater or a gas combustion device to a drying object such as clothes put into a drum and drying the device.

1 is a diagram illustrating an existing dryer structure, which is an exploded perspective view showing the main structure thereof.

Referring to FIG. 1, a drum 1 is installed inside a cabinet (not shown) constituting the exterior of a dryer. The drum 1 is generally cylindrical and formed in an open shape in the front and rear thereof, and a belt groove 2 around which a belt (not shown) driven by a separate driving source is wound is formed along the outer circumferential surface thereof.

A drying chamber 5, which is a space in which drying proceeds, is formed in the drum 1, and inside the drum 1, the object to be dried in the drying chamber 5 is pulled up when the drum 1 is rotated. A plurality of lifts 6 (lift) are formed to invert the object to be dried, thereby increasing the drying efficiency.

The front supporter 7 and the rear supporter 9 are provided to correspond to the front end and the rear end of the drum 1, respectively. Here, the front supporter 7 and the rear supporter 9 serve to block the front and rear of the drum 1 to form a drying chamber 5 and to support the front and rear ends of the drum 1, respectively. .

In addition, a sealing member 10 is installed between the front supporter 7 and the rotating drum 1 and between the rear supporter 9 and the rotating drum 1 to prevent leakage.

Of course, the front supporter 7 and the rear supporter 9 are provided with a plurality of rollers (not shown) for supporting the drum 1 at corresponding positions of the front and rear of the drum 1, respectively.

On the other hand, the front supporter (7) is formed with a through hole (8) for communicating the drying chamber 5 and the outside. The through hole 8 is selectively opened and closed by a door (not shown).

In addition, a hot air supply duct 12 is installed in the rear supporter 9, and the hot air supply duct 12 serves as a passage for supplying hot air to the drying chamber 5. In communication with.

In addition, one side of the front supporter 7 corresponding to the lower end of the through hole 8 of the front supporter 7 is provided with an outlet assembly 13 which is a portion through which the air escapes from the drying chamber 5.

In addition, the outlet assembly 13 is provided with a lint filter 14. The lint filter 14 serves to filter foreign matter (for example, seams or dust) mixed in the air exiting the drying chamber 5.

On the other hand, the lint duct 15 is installed in communication with the outlet assembly 13, the lint filter 14 is located to the interior of the lint duct 15. A blower 17 is installed to be connected to the lint duct 15 to suck air from the drying chamber 5 through the lint duct 15. The blower 17 is installed inside the blower housing 18.

One side of the blower housing 18 communicates with the lint duct 15, and an exhaust pipe 19 is connected to the other side.

Therefore, the air exiting the drying chamber 5 and passing through the lint duct 15 is discharged to the outside through the exhaust pipe 19 by the blowing action of the blower 17.

On the other hand, the guide funnel 16 (Guide funnel) is connected to the inlet side of the hot air supply duct (12). The guide funnel 16 serves to guide the hot air generated by the combustion of the gas to the inlet side of the hot air supply duct.

In addition, at the inlet side of the guide funnel 16, a valve for controlling the gas supplied from the gas pipe, a mixing pipe for mixing the gas injected from the gas nozzle and the primary air, an ignitor for ignition of the mixed gas, and the like. Gas combustion device 20 made of a is installed.

On the other hand, the drum applied to such a dryer is generally molded through the following process.

2, first, the front, rear, and center portions of the drum are separately made.

At this time, each part is prepared by preparing a sheet of metal material such as stainless steel, rolling it into a cylindrical shape, and then welding abutting joints.

Then, the front, rear, and center portions of the drum 1 are connected to each other through seaming processing as shown in FIG. 2 to complete molding of the drum.

However, such a conventional drum forming method causes various problems as described below.

That is, according to the conventional drum forming method for dryers, the drum 1 is divided into the front, rear, and center parts, respectively manufactured separately, and then seamed again to be combined so that the manufacturing process becomes complicated and the number of processes increases. There is this.

In addition, there is a high possibility that the existing drum (1), which is separately manufactured and connected to the front, rear, and center, may be manufactured so that the concentricity of each part does not match. In this case, when directly applied to a product such as a dryer, vibration and noise are increased. Etc. There is a problem that adversely affects product reliability.

The present invention has been made to solve the above problems of the prior art, by improving the molding method of the drum for the dryer to improve the workability during manufacturing by integrally manufacturing the drum can be improved the overall roundness of the drum The purpose of the present invention is to improve the reliability of the dryer by reducing vibration and noise during product application.

Meanwhile, an object of the present invention is to provide a dryer having high reliability by optimizing a structure of a dryer drum to be suitable for an improved drum forming method.

The present invention to achieve the above object, forming a cylindrical drum; Expanding both ends of the cylindrical drum; Processing a bead on an expansion portion of the cylindrical drum; A bending drum forming method for a dryer is provided, comprising: performing a hemming process by bending the overlapping ends of the cylindrical drum to overlap each other.

According to another aspect of the present invention for achieving the above object, a motor, an upper cam connected to the rotating shaft of the motor, an upper core mold installed to be expanded and contracted radially along the upper cam, An upper mold assembly spaced apart from the upper core mold, the upper mold assembly including an upper outer mold that can be lifted and separated from the upper core mold; An intermediate core mold assembly comprising an intermediate cam installed on an axis connected to the rotation axis of the motor in a straight line, and an intermediate core mold installed to expand and contract in a radial direction along the intermediate cam and having an evacuation groove formed on an outer surface thereof. Wow; In the same configuration as the upper mold assembly, the lower mold assembly which is located opposite the upper mold assembly, and a press for pressing the upper mold assembly; drum forming method comprising a drum forming machine comprising; Inserting a cylindrical drum outside the middle core mold, and the center portion is extended as a plurality of molds located inside the drum push the allocated area of the drum inner peripheral surface from the inside to the outside while leaving both ends intact And performing a bead molding process at a predetermined position among the portions other than the expanded molded portion of the drum, and performing a hemming process by bending to overlap the edges of the drum. A drum forming method for the same is provided.

On the other hand, according to another aspect of the present invention, the cylindrical body portion having a joint portion joined by butt welding to the parts of the metal material which abut each other; Openings provided at both ends of the body part to have a diameter smaller than that of the body part; A bead portion formed to reinforce strength in the body portion; It is provided with a dryer drum, characterized in that it comprises a hemming portion that is hemmed so that the edges of the opening overlap.

Hereinafter, the present invention will be described with reference to the accompanying drawings, FIGS. 3 to 7.

First, Figure 3 is a block diagram showing the drum forming process of the present invention, Figure 4 is a reference diagram showing the drum state by the forming process of Figure 3, roughly divided into the drum forming process for the dryer of the present invention, cylindrical drum ( 1) forming, expanding both ends of the cylindrical drum (1), and processing the beads (1b) on the expansion (1a) of the cylindrical drum (1); The bending is performed so that the edges of both ends of the cylindrical drum 1 overlap and are folded.

At this time, the step of forming the cylindrical drum (1) is made by preparing a sheet of metal material (stainless steel, etc.), rolling it into a cylindrical shape, and then welding the butt joints of the sheet.

When the bead 1b is formed in the central portion of the cylindrical drum 1, the bead 1b is processed using the roller 70.

On the other hand, it will be described in detail below in more detail in connection with the drum forming process of the drum 1 of the present invention described above.

Figure 5 is a block diagram showing the drum molding process of the present invention in more detail, Figure 6a to 6j is a reference state diagram showing the drum and forming apparatus for each molding process, which is applied to the drum (1) molding of the present invention The drum molding machine includes a motor 30, an upper cam 41 connected to a rotation shaft of the motor 30, and an upper core mold 42 installed to be expandable and contractable in a radial direction along the upper cam 41. And an upper mold assembly (40) spaced apart from the upper core mold (42) and including an upper outer mold (43) that can be lifted and separated from the upper core mold (42); An intermediate cam 51 installed on an axis connected to the rotational axis of the motor 30 in a straight line, and installed to be able to expand and contract in a radial direction along the intermediate cam 51, and an evacuation groove 520 is formed on the outer surface. An intermediate core mold assembly 50 including an intermediate core mold 52 formed thereon; A lower mold assembly (60) having the same configuration as the upper mold assembly (40) and positioned opposite the upper mold assembly (40); It is configured to include a press (not shown) for pressing the upper mold assembly 40.

That is, the lower mold assembly 60 includes a lower cam 61 installed on an axis passing through the intermediate core mold 52, and a lower core installed to expand and contract in a radial direction along the lower cam 61. A mold 62 and a lower outer mold 63 spaced apart from the lower core mold 62 and separately liftable from the lower core mold 62 are included.

Then, the drum forming process using the drum molding machine configured as described above is as follows.

First, the cylindrical drum 1 is inserted outside the middle core mold 52 of the drum molding machine (see FIG. 6A).

At this time, the lower end of the cylindrical drum (1) inserted outside the intermediate core mold (52) is supported by the intermediate core mold (52) and the lower core mold (62), and the lower outer mold (63) outside thereof. .

Here, the cylindrical drum 1 may be made by rolling a sheet of metal material (eg, stainless steel) into a cylindrical shape as described above, and then welding the abutted joints, or by other known methods. You may lose.

On the other hand, after inserting the cylindrical drum 1 outside the middle core mold 52 of the drum molding machine, the upper mold assembly 40 is lowered by a predetermined distance by the pressing force of the press (not shown). (1) The upper end is inserted between the upper core mold 42 and the upper outer mold 43 constituting the upper mold assembly 40 (see FIG. 6B).

Although not shown in this state, when the upper core mold 42 and the lower core mold 62 is expanded to the outside finely, the upper and lower ends of the drum are clamped.

Then, the middle core mold 52 is expanded to the outside in the state where the upper and lower ends of the drum 1 are clamped, thereby expanding the middle portion of the drum.

That is, with both ends of the drum in place, the center portion expands as a plurality of molds located inside the drum push the allocated area of the drum inner circumferential surface from inside to outside (see FIG. 6C).

Subsequently, after expansion of the drum 1 center portion is completed, the evacuation process of the upper outer mold 43 and the lower outer mold 63 is performed (see FIG. 6D).

Then, the process which shape | molds the bead 1b in the expansion pipe part 1a of the drum 1 center is performed (refer FIG. 6E).

At this time, in forming the beads 1b at the central portion of the cylindrical drum 1, the core mold rotates as the motor 30 of the drum molding machine is driven, and in this state, the core mold is rotated. Each roller 70 moves in the direction of the corresponding evacuation groove 520 to press the outer peripheral surface of the drum 1 so that the portion pressed by the roller 70 is deformed in the shape of the evacuation groove 520 so that bead molding is performed. Will be done.

Subsequently, after the bead molding is completed, a bending hemming process is performed to overlap both edges of the drum 1 (see FIG. 6F).

Then, after all processing for forming the drum is completed until the hemming processing for both edges is completed, the core molds 42, 52, 62 are moved to the drum 1 by the contracting motion in the direction of the arrow in the drawing. ), And the interference between the core molds and the drum 1 is eliminated so that the drum 1 can be released from the core mold.

At this time, the lower outer mold 63, which has been retracted outwards before the contracting operation of the core molds, moves to a position capable of supporting the lower end of the drum 1.

On the other hand, the upper mold assembly 40 is raised after the interference between the core mold and the drum 1 is excluded, so that the drum can be taken out from the drum molding machine if the interference in the upper direction is completely excluded (Fig. 6H). Reference).

According to the drying drum forming method of the present invention as described above, the phenomenon in which the roundness of the center portion of the drum is lowered is also eliminated by simultaneously expanding the intermediate portion of the drum 1 as a whole.

Therefore, when the drum manufactured by the molding method of the present invention is applied to the product, the appearance of the drum can be kept smooth, and vibration and noise can be minimized when the product is applied.

In the drum forming process, the bead forming process is the drum is rotated by the rotation of the core mold, the roller 70 may be formed while rotating the drum 70 along the drum outer peripheral surface while the drum 1 is stopped, of course, to be.

On the other hand, Figure 7 is a front view showing the structure of the drum produced in accordance with the expansion method of the present invention, the dryer drum (1) expansion molded according to the method of the present invention is joined to the parts of the metal material abutted by butt welding A cylindrical body portion having a joined portion; Openings provided at both ends of the body part to have a diameter smaller than that of the body part; A bead portion formed to reinforce strength in the body portion; It is provided with a hemming portion that is hemmed so that the edge of the opening overlap.

At this time, the metal material is configured to have a thickness of 0.5 ~ 0.8mm, more preferably characterized in that the metal material has a thickness of 0.55 ~ 0.7mm.

In addition, the inner diameter ratio (or outer diameter ratio) of the opening of the drum 1 to the body portion is configured to be 0.9 or more, and more preferably, the ratio of the inner diameter of the opening portion of the drum 1 to the inner diameter of the body portion is 0.93 to 0.94. It is characterized by.

The depth C from the outer diameter of the body portion (i.e., the enlarged center portion) adjacent to the opening portion (i.e., both ends of the drum) to the outer diameter of the opening portion is configured to be 25 mm or less. That is, the expansion depth C is configured to be 25 mm or less.

On the other hand, the metal material is a metal material is a stainless steel or galvanized plate-based, for example, made of one of STS, SGCC, SGCH, SFCH, SECC, the metal material is any one of SGCC, SGCH, SFCH, SECC In one case, a coating layer may be formed on the metal material.

In addition, a vibration damping band (not shown) made of rubber or metal may be installed on the outer wall of the body portion or the bead portion.

And, the width or number of the bead portion may be appropriately changed according to the type or capacity of the clothes dryer. That is, the shape of the bead provided in the drum is not limited to the shape of the bead shown in each drawing including FIG. 7 of the present specification, and the width, number, etc. of the bead vary as necessary.

On the other hand, non-welded portions that are not welded by a predetermined length may be provided on both sides of the joint to facilitate hemming.

In the dryer drum (1) configured as described above means that the thickness of the metal material should be configured to fall within the range of 0.5 ~ 0.8mm as follows.

First, when the thickness of the metal material (STS, SGCC, SGCH, SFCH, SECC) is less than 0.5mm, the problem that the metal material is torn during expansion molding occurs.

In addition, when the thickness is smaller than 0.5 mm, the noise is increased when the metallic button or the like of the garment hits the drum 1 during the drying process.

On the other hand, when the thickness of the metal material is greater than 0.8mm, as well as the material cost rise, the press pressure should be increased during expansion molding from the manufacturing side, the weight is heavy, there is a difficulty in assembling the drum (1) in the cabinet. In addition, a heavy load is applied to a roller (not shown) that supports the drum 1 from both sides in a state in which the weight is assembled to the product.

Therefore, the dryer drum 1 of the present invention should be configured so that the thickness of the metal material is within the range of 0.5 ~ 0.8mm to solve the above problems.

Next, the meaning of the inner diameter of the opening 1 to the inner diameter or the outer diameter of the drum 1 (in other words, the expansion depth) is as follows.

When the drum 1 is produced by the expansion molding method as in the present invention, the thickness of the metal material significantly affects the degree of expansion. That is, since expansion is using ductility of a metal material, when a metal material is too thin, it cannot expand as much as needed.

On the other hand, in consideration of increasing the volume of the drum in the cabinet (not shown) of a limited size, the drum body should be extended over a certain range, but the opening of the drum 1 and the front support (7: FIG. 1) in front of the drum. Considering the interrelationship and the like, the inner ratio of the trunk portion and the opening portion needs to be determined within a predetermined range.

To this end, the present invention is optimized through a number of experiments to provide a structure of a drum for a dryer that can be expanded to the body as necessary to the minimum thickness of the metal material.

The present invention is a range satisfying this, and it is possible to prevent the metal material from being torn when the opening-to-body portion inner diameter (B / A) is 0.9 or more. In addition, the optimum range which considered stability etc. is about 0.93-0.94.

That is, as a preferred embodiment of the present invention, the thickness of the metal material (STS) is 0.5 mm, the outer diameter of the trunk portion is 663 mm, the outer diameter of the opening portion is 616 to 623 mm, and the difference in diameter between the outer diameter of the trunk portion and the outer diameter of the opening portion is 40 to 47 mm. The distance (C, expansion depth; see Fig. 7) from the outer diameter of the trunk portion to the outer diameter of the opening portion is 20 to 23.5 mm.

When the thickness of the metal material STS is 0.5 mm and the outer diameter of the trunk portion is 663 mm, and the inner portion ratio of the trunk portion to the opening ratio is 0.9, the diameter difference between the outer diameter of the trunk portion and the outer diameter of the opening portion is 67 mm. The distance C from the outer diameter to the outer diameter of the opening is 33.5 mm.

If the pipe depth is larger than 33.5 mm, the metal material is torn during molding, so that it is less than that.

On the other hand, according to another embodiment of the present invention, when the thickness of the metal (SECC) is 0.6mm, the pipe depth is about 44mm is suitable.

And, the drum of the present invention is formed with at least one bead portion in the body portion for strength reinforcement.

In addition, in order to absorb or reduce the noise and vibration caused by the laundry inside the drum 1, a damping band is wound around the outer diameter of the trunk or the bead portion where the belt is not wound.

At this time, the vibration damping band may be made of rubber or metal material, and the vibration damping band is fixed in a form in close contact with the outer wall of the body part or the outer wall of the bead part. That is, the damping band is attached to the body portion or the outer wall of the bead portion or wound in a taut state.

On the other hand, the joining part of the drum 1 is butt-welded using the Plasma-TIG welding machine (welding in the state which the edge part of a metal material does not overlap each other but abuts). The reason is that when the metal materials overlap each other, it is not possible to ensure a uniform deformation amount with other portions during expansion pipe forming.

In addition, both ends of the joint portion should not be joined by a predetermined length for the hemming treatment of the opening end.

In the present specification, the forming process of the drum used in the dryer has been described as an example, but the present invention may be applied to the forming process of not only the drum applied to the dryer, but also any type of drum requiring expansion of the central portion.

On the other hand, the present invention is not limited to the above embodiments, various modifications and changes are possible without departing from the scope of the technical spirit of the present invention.

As described above, the present invention by improving the molding method of the drum for the dryer to improve the workability during manufacturing by integrally manufacturing the drum, and to improve the overall roundness of the drum vibration and noise when applying the product This reduces the effect of improving the reliability of the dryer.

In addition, the present invention improves the formability of the drum by providing an optimized drum structure suitable for the above-mentioned expansion molding method of the drum, and improves the reliability of the dryer when the product is applied.

1 is an exploded perspective view showing a structural example of an existing dryer;

2 is a cross-sectional view showing the structure of a conventional drum

Figure 3 is a block diagram showing a drum forming process of the present invention

4 is a reference diagram showing the drum state according to the molding process of FIG.

Figure 5 is a block diagram showing in more detail the drum molding process of the present invention

6A to 6G are reference state diagrams showing drums and molding apparatus for each molding process;

Figure 6a is a cross-sectional view showing a molding apparatus before drum insertion

Figure 6b is a sectional view showing a lower support state immediately after the drum insertion

Figure 6c is a view showing a state after the upper drum support by lowering the upper mold assembly

Figure 6d is a view showing a state immediately after expansion molding by the expansion of the intermediate core assembly;

Figure 6e is a view showing the retracted state of the upper and lower outer mold for the bead and hemming

6F is a state diagram at the time of forming a bead

Fig. 6G is a state diagram after hemming

Fig. 6h is a view showing a state in which the drum is released by the shrinkage operation of the core mold after all processing is completed.

Figure 6i is a state diagram after the upper mold assembly rises

7 is a front view showing the structure of the drum manufactured according to the method of the present invention;

* Explanation of symbols for main parts of the drawings

1: Drum 1a: Expansion part

1b: Bead 30: Motor

40: upper mold assembly 41: upper cam

42: upper core mold 43: upper outer mold

50: middle core mold assembly 51: middle cam

52: middle core mold 520: evacuation groove

60: lower mold assembly 61: lower cam

62: lower core mold 63: lower outer mold

70: roller

Claims (22)

Forming a cylindrical drum; Expanding a portion excluding both ends of the cylindrical drum; Processing the beads in the expansion portion of the cylindrical drum; And performing a hemming process by bending the overlapping edges of the cylindrical drum to overlap each other and forming the edge of the cylindrical drum. The method of claim 1, Forming the cylindrical drum, A method of forming a drum for a dryer, comprising: preparing a sheet of metal, rolling it in a cylindrical shape, and then welding abutting joints. The method of claim 1, Drying drum molding method characterized in that the bead is processed by using a roller when forming a bead in the central portion of the cylindrical drum. A motor, an upper cam connected to the rotating shaft of the motor, an upper core mold installed to be expanded and contracted radially along the upper cam, and spaced apart from the upper core mold and spaced apart from the upper core mold. An upper mold assembly comprising an upper and lower mold that is separately liftable; An intermediate core mold assembly comprising an intermediate cam installed on an axis connected to the rotation axis of the motor in a straight line, and an intermediate core mold installed to expand and contract in a radial direction along the intermediate cam and having an evacuation groove formed on an outer surface thereof. Wow; In the same configuration as the upper mold assembly, the lower mold assembly which is located opposite the upper mold assembly, and a press for pressing the upper mold assembly; drum forming method comprising a drum forming machine comprising; Inserting a cylindrical drum outside the intermediate core mold; With the both ends intact, a plurality of molds located inside the drum extends the center portion as each of the molds pushes the allocated area of the drum inner circumferential surface from the inside out; Performing a bead forming process at a predetermined position among the portions other than the expanded molded portion of the drum, Drying drum forming method characterized in that it comprises the step of performing a bending hemming (hemming) folding so as to overlap both edges of the drum. The method of claim 4, wherein The processing step of forming a bead in the central portion of the cylindrical drum, Rotating the core mold as the motor of the drum molding machine is driven, Drying drum forming method, characterized in that the pressurized portion of the drum is deformed in the shape of the evacuation groove as the roller presses the drum toward the evacuation groove of the core mold. The method of claim 4, wherein After completing the hemming process by bending to overlap the edges of both ends except for the centered portion of the drum, the step of eliminating the interference between the core mold and the drum is carried out as the core mold is retracted inward. Dryer drum forming method characterized in that it further comprises. The method of claim 6, Drying drum forming method characterized in that the upper mold assembly is raised after the interference between the core mold and the drum is removed. The method of claim 7, wherein The interference between the core mold and the drum is excluded, and the drum ejecting step is performed after the upper mold assembly is raised. The method according to any one of claims 1 to 8, Drying drum forming method characterized in that the drum is stainless steel. A motor, an upper cam connected to the rotating shaft of the motor, an upper core mold installed radially expandable and contractable along the upper cam, and spaced apart from the upper core mold and separately from the upper core mold. An upper mold assembly comprising a liftable upper outer mold; An intermediate core mold assembly comprising an intermediate cam installed on an axis connected to the rotation axis of the motor in a straight line, and an intermediate core mold installed to expand and contract in a radial direction along the intermediate cam and having an evacuation groove formed on an outer surface thereof. Wow; In the same configuration as the upper mold assembly, the lower mold assembly which is located opposite the upper mold assembly, and the press for pressing the upper mold assembly; drum forming method of a dryer using a drum molding machine comprising a; Inserting a cylindrical drum out of the middle core mold of the drum forming machine, A drum upper end is inserted between the upper core mold and the upper outer mold as the upper mold assembly descends, The upper core mold and the lower core mold are extended outward to clamp the upper and lower ends of the drum; And expanding the middle portion of the drum by expanding the intermediate core mold to the outside in the state where the upper and lower ends of the drum are clamped. A cylindrical body part having a joint part joined by butt welding to a part of the metal material which is in contact with each other; Openings provided at both ends of the body part to have a diameter smaller than that of the body part; A bead portion formed to reinforce strength in the body portion; Drying drum characterized in that it comprises a hemming portion that is hemmed to overlap the edge of the opening. The method of claim 11, Dryer drum, characterized in that the metal material has a thickness of 0.5 ~ 0.8mm. The method of claim 12, Dryer drum, characterized in that the metal material has a thickness of 0.55 ~ 0.7mm. The method according to claim 12 or 13, Drying drum, characterized in that the inner diameter of the opening to the inner diameter of the body portion is 0.9 or more. The method of claim 14, Drying drum, characterized in that the inner diameter of the opening to the inner diameter of the body portion is 0.93 ~ 0.94. The method of claim 12 or 13, And a depth from an outer diameter of the opening adjacent body portion to an outer diameter of the opening is 25 mm or less. The method of claim 11, The metal material is a stainless steel drum, or a dryer drum, characterized in that the galvanized sheet series. The method according to claim 11 or 17, Drying drum, characterized in that the metal material is one of STS, SGCC, SECC, SGCH, SFCH. The method of claim 18, Dryer drum, characterized in that the coating material is formed on the metal material when the metal material is SGCC or SECC. The method of claim 11, Drying drum, characterized in that the vibration damping band of the rubber or metal material is installed on the outer wall of the body portion or the bead portion. The method of claim 11, The opening drum has a relatively small diameter by expanding the forming of the body portion drum. The method of claim 11, And a non-welded portion which is not welded by a predetermined length for hemming at both ends of the joint portion is formed.