KR20160111207A - Fractal grill and outdoor unit of air conditioner having fractal grill - Google Patents

Abstract

The present invention relates to a fractal grill and an outdoor unit of an air conditioner having the same comprising: a border part forming a shape of a perimeter; a circular grill core formed in an area spaced from the border part; and a grill part opened within an area between the border part and the grill core to allow air to flow in and out, wherein the grill part defines a plurality of openings through which air passes by a plurality of fractal structures arranged radially around the grill core.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an outdoor unit of an air conditioner having a fractal grille and a fractal grill,

The present invention relates to an outdoor unit of an air conditioner provided with a fractal grill and a fractal grill.

The air conditioner is an appliance for keeping the indoor air in the most suitable condition according to the purpose and purpose. For example, in the summer, the room is controlled by a cool air condition, while in winter the room is controlled by a warm heating condition, by the humidity of the room, and by the clean air of the room.

In detail, the air conditioner is driven by a refrigeration cycle for compressing, condensing, expanding and evaporating the refrigerant, thereby performing the cooling or heating operation of the indoor space.

Such an air conditioner can be divided into a separate type air conditioner in which the indoor unit and the outdoor unit are separated from each other and an integrated type air conditioner in which the indoor unit and the outdoor unit are combined into one unit according to whether or not the indoor unit and the outdoor unit are separated. The outdoor unit includes an outdoor heat exchanger that exchanges heat with outdoor air. The indoor unit includes an indoor heat exchanger that performs heat exchange with indoor air.

When the refrigeration cycle is a cooling operation, the outdoor heat exchanger functions as a condenser, and the indoor heat exchanger functions as an evaporator. On the other hand, when the refrigeration cycle performs the heating operation, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator.

The outdoor unit of the air conditioner may include a plurality of structures including an outdoor heat exchanger in which a refrigerant for heat exchange flows, a compressor for compressing refrigerant, and a blower fan for forced flow of air.

The case of the outdoor unit is provided with a suction grill in which outside air flows into the outdoor unit and a discharge grille in which air heat-exchanged in the outdoor unit is discharged to the outside.

The air sucked through the suction grille by the blowing fan is heat-exchanged with the refrigerant while passing through the outdoor heat exchanger. The heat-exchanged air is discharged to the outside through the blowing fan through the discharge grille.

Meanwhile, the discharge path resistance varies according to the shape and structure of the discharge grill, so that the rotating speed of the blowing fan to be operated can be determined and the noise can also be determined.

Accordingly, discharge grilles having various structures for improving the air flow structure of the discharge grille have been developed.

For example, Korean Patent Registration No. 10-0150089 comprises a plurality of concentric grills and a straight line extending outwardly from the center side, and the flesh and grill of the discharge grill are formed into a hemispherical shape with respect to the center side Thereby improving the flow of air and reducing noise.

Korean Patent Registration No. 10-0408781 discloses an air conditioner comprising a plurality of ribs arranged concentrically with a fan guard through which the air inside the outdoor unit is discharged and a plurality of ribs bent in the rotating direction of the fan, So as to improve the flow of the discharged air and to prevent noise generated during the operation of the fan.

This conventional technique has a problem in that it can not attenuate the turbulence structure, which is the main noise at the fan downstream, due to the design of the flow direction of air according to the rotation direction of the fan.

The embodiment of the present invention is characterized in that it is provided with a fractal grill and a fractal grill which are formed of a fractal structure arranged radially with respect to the center of rotation of the blowing fan and are capable of reducing the vortex intensity of air passing therethrough and reducing noise, And it is an object of the present invention to provide an outdoor unit of an air conditioner.

The outdoor unit of the air conditioner includes a case having an outer appearance and having a blowing fan and an outdoor heat exchanger therein; And a discharge grill mounted on one side of the case to form a part of an outer surface of the case and having a plurality of discharge ports through which air discharged by the blowing fan passes is formed in the discharge grill, A grill core formed on one side of the discharge grill; And a grill portion for defining the discharge port is formed by a plurality of fractal structures arranged radially with respect to the grill core.

Further, a fractal grill according to an embodiment of the present invention includes: a rim portion forming a peripheral shape; A circular grill core formed in a region away from the rim portion; And a grill portion which is opened in the region between the rim portion and the grill core and through which air is passed; Wherein the grille portion defines a plurality of openings through which air is passed by a plurality of flectal structures radially disposed about the grill core.

The plurality of fractal structures are rotatably arranged at regular intervals around the grill core.

And the plurality of fractal structures are formed continuously in the radial direction with respect to the grill core.

The fractal structure has a structure in which the unit shape is embedded in each corner of a unit shape formed by a pair of arcs spaced from each other around the grill core and a pair of straight lines connecting the ends of the arcs Is repeatedly defined.

The grill portion includes a main flared portion having a plurality of corners and opened; And a subfractal portion having the same shape as that of the mainframe portion and having a smaller size at the plurality of corners.

And the subfrac- tral portion includes another subfra- cle portion having the same shape as the subfra- cle portion and having a smaller size at a plurality of corners of the subfra- cle portion.

The grill portion may further include a plurality of concentric circular grills centered on the grill core and formed at regular intervals.

And the circular grill is arranged from the outer region of the grill portion to the rim portion.

A plurality of subfraktal parts are connected to an outer circumferential surface of the grill core and a subfrequal part closest to the grill core is connected to the outer circumferential surface of the grill core and a subfrequal part farthest from the grill core is connected to the edge part.

The grill portion may further include a reinforcing grille connecting the plurality of subfraxel portions to each other.

The grill portion may further include a straight grill connecting the grill core and the rim portion and radially disposed around the grill core.

The straight grill divides a space between the grill core and the rim portion, and the flectal structure is provided for each of the divided spaces.

And the linear grille is formed between the adjacent mainframe portions.

Wherein the straight grill includes: a first straight grill connecting the rim portions of the grill core; A second straight grill connecting the subframal portion closest to the grill core and the grill core among the plurality of subfracture portions; And a third linear grille connecting the subframe portion closest to the rim portion and the rim portion among the plurality of the subfractal portions.

According to the outdoor unit of the air conditioner provided with the fractal grill and the fractal grill according to the embodiment of the present invention, the shape of the grill is formed into a fractal shape radially arranged around the grill core, The overall eddy current intensity is reduced, and the noise can be remarkably reduced due to the reduction of vortex.

In addition, since the structure of the grill of a general outdoor unit is visually and structurally remarkably different from that of the conventional outdoor unit, it is possible to differentiate it from existing products.

The flare structure provided on the grille is radially arranged with respect to the center of the grille, thereby providing a flare structure inside the grille area and maintaining the strength thereof.

Further, on the grill, a reinforcing grill connecting the fractal structure, or a straight grill extending outward from the center of the grill, or a plurality of concentric circular grilles concentric with the grille, Can be stably implemented.

1 is a perspective view of an outdoor unit of an air conditioner according to a first embodiment of the present invention.
2 is an exploded perspective view of the outdoor unit.
3 is a sectional view taken along the line 3-3 'in Fig.
4 is a front view of the discharge grill according to the first embodiment of the present invention.
5 is a graph showing a noise state during the operation of the outdoor unit.
6 is a front view of a discharge grill according to a second embodiment of the present invention.
7 is a front view of a discharge grill according to a third embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. It is to be understood, however, that the spirit of the invention is not limited to the embodiments shown and that those skilled in the art, upon reading and understanding the spirit of the invention, may easily suggest other embodiments within the scope of the same concept.

1 is a perspective view of an outdoor unit of an air conditioner according to an embodiment of the present invention. 2 is an exploded perspective view of the outdoor unit. 3 is a cross-sectional view of the outdoor unit, taken along line 3-3 'in Fig.

As shown in the drawings, the outdoor unit 1 of the air conditioner according to the embodiment of the present invention has an outer appearance formed by a case having a rectangular parallelepiped shape. The case includes a base pan 11 forming a bottom surface of the outdoor unit 1, a top cover 12 forming an upper surface of the outdoor unit 1, And a rear plate 14 which forms at least a part of the rear surface and both side surfaces of the outdoor unit 1. [ The front plate 13 and the rear plate 14 are disposed between the base pan 11 and the top cover 12 to form an overall outer shape.

The inner space of the outdoor unit 1 may be partitioned into a heat exchange space 211 and a machine room 212 by a barrier 21. An outdoor heat exchanger 22 and a blowing fan 23 are disposed in the heat exchange space 211. The machine room 212 may be provided with a compressor 24 and various valves constituting a refrigeration cycle. The outdoor heat exchanger (22) and the compressor (24) can be fixedly mounted to the base pan (11).

The outdoor heat exchanger 22 extends along the side and rear ends of the base pan 11 and is disposed at a position corresponding to the area of the inlet 141 formed in the rear plate 14. [ Therefore, all the air sucked into the inlet 141 passes through the outdoor heat exchanger 22, and heat exchange with the refrigerant passing through the inside of the outdoor heat exchanger 22 becomes possible.

On the other hand, a mounting bracket 25 is provided in front of the outdoor heat exchanger 22. The lower end of the mounting bracket 25 is fixed to the base pan 11 and the upper end is bent to be fixed to the top cover 12 or the front plate 13 or the rear plate 14.

The mounting bracket 25 is provided with a motor mounting portion 251 for mounting the fan motor 26 therein. The fan motor 26 can be fixedly mounted on the mounting bracket 25 and the rotation axis of the fan motor 26 extends forward.

The blowing fan 23 is coupled to the rotating shaft of the fan motor 26. The blowing fan 23 may be an axial flow fan having a plurality of blades 232 at a central hub 231 coupled to a rotating shaft. Air is sucked through the suction port 141 of the rear plate 14 when the blowing fan 23 rotates and the sucked air passes through the blowing fan 23 to the discharge grille 23 of the front plate 13, (30).

On the other hand, the front plate 13 is provided with the discharge grill 30. The discharge grill 30 may correspond to or slightly larger than the diameter of the blowing fan 23, and may be formed in a rectangular shape.

The front plate 13 may be formed of a metal material, and a grill mounting hole 131 through which the discharge grill 30 can be mounted is formed. The discharge grill 30 can be fixedly mounted on the grill mount 131 and can be coupled onto the front plate 13.

The discharge grill 30 forms a plurality of discharge openings 301 through which the air inside the outdoor unit 1 is discharged to the outside of the outdoor unit 1 so that the discharged air is discharged from the front surface 31 of the discharge grill 30 A plurality of the discharge ports 301 are formed on the front surface 31 and the circumferential surface 32 of the discharge grill 30 so as to be three-dimensionally discharged through the peripheral surface 32 and the peripheral surface 32.

The discharge grill 30 is injection-molded from a plastic material to form a circumferential surface 32 with the front surface 31. A plurality of discharge ports 301 are formed on the entire front surface 31 and the circumferential surface 32 of the discharge grill 30 so that the air inside the outdoor unit 1 is discharged toward the outside of the outdoor unit 1 So that it can be discharged three-dimensionally.

Hereinafter, the structure of the discharge grill will be described in more detail with reference to the drawings.

4 is a front view of the discharge grill according to the first embodiment of the present invention.

As shown in the drawing, the discharge grille 30 has a rim 312 around a generally rectangular front surface 31. A coupling portion 313 for coupling with the front plate 13 is formed at the four corners of the rim 312. A coupling member such as a screw is fastened to the coupling portion so that the discharge grill 30 can be fixedly mounted on the front plate 13. [

 The rim portion 312 may be formed to have a predetermined width along the front surface of the discharge grill 30. [ A grill core 311 is formed at the center of the inside of the rim 312, at the center of the rim 312. The grill core 311 may be formed in a circular shape and may be positioned in front of the hub 231 of the blowing fan 23 and have a size corresponding to the size of the hub 231.

A plurality of grill portions 33 may be formed in the opening region between the grill core 311 and the rim portion 312 and the grill portions 33 may be formed by the grill portions 33 So that a discharge port 301 through which air can be discharged can be defined.

The grill portion 33 may include a fractal portion 34 having a flectal structure and the circular grill 35 and the rim portion 361 and the reinforcing grill 37 may be further combined, A plurality of discharge ports can be formed on the front surface of the discharge port 30.

In detail, a plurality of the fractal parts 34 may be radially arranged around the center of the grill core 311, that is, the discharge grill 30. As the grille core 311 is closer to the grille core 311, the size of the grille core 311 is increased.

The fractal portion 34 may include a mainframe portion 341 having a largest size and a subfractal portion 342 having a smaller size than the mainframe portion 341. The main fringe part 341 is formed to have a predetermined size and the sub flectal part 342 is formed to have a half size of the length of each line forming the main flectal part 341, (Not shown).

The subfracture portion 342 includes a first subfraxel portion 342a formed at four corners of the mainframe portion 341 and a second subfragment portion 342b formed at the four corners of the first subfraxel portion 342a. And a portion 342b. At this time, the second subfraxel portion 342b may be formed to have the same size as the ratio of the mainframe portion 341 and the first subfraxel portion 342a.

Of course, additional subfracel portions may be formed at the four corners of the second subfraxel portion 342b. Further, the subfraxel portion may be formed in a smaller size depending on the space constraint.

Meanwhile, the main fringe portion 341 and the subfraxel portion 342 may be formed to have the same shape only with different sizes. Hereinafter, a specific shape will be described with reference to the main flectal portion 341. Since the sub-flectal portion 342 has the same structure as that of the sub flectal portion 342 only, the detailed description thereof will be omitted.

The main fringe part 341 may be defined by a pair of circular arc 341a spaced apart from the grill core 311 by a predetermined distance and a straight line 341b connecting both ends of the pair of circular arc 341a. have. At this time, since the main flectal part 341 is formed by ribs, the outer side and the inner side of the main flectal part 341 are both opened.

The main fringe part 341 is formed in a shape similar to a trapezoid by the arc 341a and the straight line 341b, but the upper part and the lower part of the trapezoid are rounded so as to have a constant curvature.

Meanwhile, the pair of circular arc 341a is formed to have a curvature corresponding thereto so as to form a part of a concentric circle around the grill core 311 at the corresponding position. Therefore, the length of the arc 341a located farther from the arc 341a located closer to the grill core 311 may be longer.

The pair of straight lines 341b form part of an imaginary line extending from the center of the grill core 311 toward the rim 312 and connect both ends of the pair of arcs 341a respectively Respectively.

The main fringe part 341 may be radially arranged around the grill core 311 and may be formed at regular intervals on the same extension line around the grill core 311. The main fringe part 341 near the grill core 311 is formed to have a smaller size than the main fringe part 341 relatively far from the grill core 311. A circular grill 35 may further be formed between the main flectal part 341 at a position close to the grill core 311 and the main flectal part 341 at a distant position.

Meanwhile, the main fringe part 341 may be formed at equal distances around the grill core 311 at regular intervals. The grille 36 may further include a rim 36 extending from the center of the grill core 311 toward the rim 312 between the adjacent main flectal parts 341.

A first subfraxel portion 342a having a half length of an arc 341a and a straight line 341b of the mainframe portion 341 is formed at the corner of the mainframe portion 341. The subfracture portion 342 is located at four corners of the main fringe portion 341 and the vertexes of the corners of the main fringe portion 341 are aligned with the center portion of the first subfraxel portion 342a .

Meanwhile, a second subfraxel portion 342b may be further formed at the corner of the first subfraxel portion 342a. The second subfraxel portion 342b may be formed to have a length equal to 1/2 of the length of the arc and the straight line of the first subfraxel portion 342a.

Further, the discharge grill 30 may further include a reinforcing grille 37. The reinforcing grill 37 is formed to be able to connect a plurality of the subframes 342 formed on the discharge grill 30 and has a rectangular or trapezoidal shape to connect the subframes 342 to each other. As well as a discharge port 301 through which air is discharged. Of course, the shape of the reinforcing grille 37 may be the same as that of the fractal portion 34. [

The reinforcing grille 37 may be formed to be connected to the grille 36 and the circular grille 35 as well as the fractal portion 34. The reinforcing grille 37 may be formed to have various sizes according to the distance from the grill core 311. [

Hereinafter, the air flow of the outdoor unit of the air conditioner according to the embodiment of the present invention will be described.

The fan motor 26 is driven according to the operation of the outdoor unit 1 to rotate the blowing fan 23.

External air is introduced into the outdoor unit (1) through the inlet (141) of the rear plate (14) by the rotation of the blowing fan (23). All the air flowing into the outdoor unit 1 passes through the outdoor heat exchanger 22 and is heat-exchanged with the refrigerant flowing along the outdoor heat exchanger 22 while passing through the outdoor heat exchanger 22 .

The heat-exchanged air passes through the blowing fan 23 according to the rotation of the blowing fan 23, and flows toward the front of the blowing fan 23. The air passing through the blowing fan 23 can be discharged to the outside of the outdoor unit 1 while passing through the discharge grille 30. [ The air passing through the discharge grill 30 can be discharged three-dimensionally through the peripheral surface 32 as well as the front surface of the discharge grill 30.

In detail, the air discharged through the front surface of the discharge grill 30 passes through the front surface of the discharge grill 30, and passes through the discharge port 301 defined by the plurality of the fractal parts 34 do.

Due to the nature of the structure of the fractal part 34, the flow of the air passing through the fractal part 34 is formed by a large and small turbulence, and the energy exchange is performed between them, . That is, it is possible to reduce the noise due to the reduction of the eddy current intensity.

5 is a graph showing a noise state during the operation of the outdoor unit.

As shown in the figure, the noise generated during the operation of the outdoor unit 1 according to the embodiment of the present invention is analyzed to determine that the noise in the turbulent noise region corresponding to the noise during the passage of the discharge grill 30 is 20 dB , Which is remarkably low compared with the noise in a general grill shape.

Meanwhile, the outdoor unit of the air conditioner according to the present invention may have various other embodiments other than the above-described embodiments.

In the second embodiment of the present invention, the grill portion of the discharge grill has a structure in which a straight grill is connected to the fractal portion, the grill core, and the rim portion.

The second embodiment of the present invention is the same as the second embodiment except for the structure of the discharge grill, so that the same reference numerals are used for the same components in order to avoid redundant description, and a detailed description thereof will be omitted.

6 is a front view of a discharge grill according to a second embodiment of the present invention.

As shown in the drawing, the discharge grill 40 according to the second embodiment of the present invention is formed in a rectangular shape, and a rim portion 412 is formed with a predetermined width along the outer periphery, The core 411 is formed. A grill portion 43 is formed in an area between the rim 412 and the grill core 411 to define a plurality of discharge openings 401 through which air can be discharged.

The grill portion 43 includes a plurality of fractal portions 44 disposed radially and a circular grill 45 disposed in an area outside the fractal portion 44 and a grill portion 45 disposed around the grill core 411 And a linear grille 46 extending radially.

 The flectral part 44 includes a main flectal part 441 composed of a pair of arcs 441a and a straight line 441b connecting both ends of the arc 441a, A main first subfraxel portion 442a formed at an edge and a second subfractal portion 442b provided at four corners of the main first subfragment portion 442a.

Since the overall structure and shape of the fractal part 44 are the same as those of the first embodiment, a detailed description thereof will be omitted.

A plurality of circular grills 45 are arranged at regular intervals between the outermost portion of the fractal portion 44 and the rim portion 412. In the section where the circular grill 45 is disposed, the air can be flowed into the section where air flow is not vigorously actuated, and a safety structure for preventing the user's body from entering is secured.

The straight grill 46 forms part of a straight line extending or extending in a straight line from the grill core 411 toward the rim 412. In detail, a first linear grill 461 of the linear grill 46 extends to connect the outer edge of the grill core 411 and the rim 412. The first straight grill 461 is arranged to divide the discharge grill 40 into four regions. At this time, the fractal parts 44 may be arranged one by one in the area partitioned by the first straight grill 461.

The second linear grill 462 of the linear grill 46 is connected to the grill core 411 and the fractal part 44. In detail, the second straight grill 462 connects the grill core 411 and the second subfragmental part 442b adjacent to the grill core 411 to support the fractal part 44, .

The third linear grill 463 of the linear grill 46 is configured to connect the rim 412 and the fractal portion 44. In detail, the third straight grill 463 connects the rim 412 and the second subframal part 442b adjacent to the rim 412 to support the fractal part 44, . At this time, the third straight grill 463 may be formed to cross the plurality of circular grilles 45 and extend toward the grill core 411.

Meanwhile, the outdoor unit of the air conditioner according to the present invention may have various other embodiments in addition to the above-described embodiments.

In a third embodiment of the present invention, the flared portion of the discharge grill has a structure in which it is in contact with the rim portion and the grill core, respectively.

The second embodiment of the present invention is the same as the second embodiment except for the structure of the discharge grill, so that the same reference numerals are used for the same components in order to avoid redundant description, and a detailed description thereof will be omitted.

7 is a front view of a discharge grill according to a third embodiment of the present invention.

As shown in the drawing, the discharge grill 50 according to the third embodiment of the present invention is formed in a rectangular shape as a whole, and includes a rim 512 forming a circumference, a grill core 511 forming a center, And a fracture part 54 having a plurality of discharge ports 501 through which air flows between the rim 512 and the grill core 511.

In detail, the rim portion 512 is formed to have a rectangular shape on the outside, and to open circularly on the inside. At this time, the opening size can be determined by the size of the fractal portion 54, and is formed to be large enough to secure a main flow path of the air discharged by the blowing fan 23. The space of the outdoor unit 1 blocked by the rim portion 512 does not substantially affect the flow of air even if the space is substantially blocked by the portion where the airflow is hardly caused.

The grille core 511 is formed in a circular shape, and the diameter of the grille core 511 can be determined by the size of the fractal portion 54.

The flectral part 54 includes a main flectal part 541 including a pair of arcs 541a and a straight line 541b connecting both ends of the arc 541a, A first subfrac- tral portion 542a formed at an edge and a second subfrac- tal portion 542b provided at four corners of the first subfrac- tive portion 542a. The overall structure and shape of the fractal part 54 can be formed in the same manner as in the first embodiment.

The second subfraxel part 542b formed at the outermost one of the fractal parts 54 may be connected to the inner end of the rim part 512 and the second subfractal part 542b formed at the innermost part And may be connected to the outer end of the grill core 511 in contact therewith. Accordingly, the fracture part 54 can be coupled to and supported by the rim 512 and the grill core 511 while forming the discharge port 501, and the strength can be reinforced.

A linear grill 56 extending linearly may be further formed between the rim 512 and the grill core 511. The straight grill 56 is extended to connect the outer edge of the grill core 511 and the rim 512. The straight grill 56 is arranged to divide the discharge grill 50 into four regions. At this time, the fractal parts 54 may be disposed one by one in the area partitioned by the straight grill 56. The straight grill 56 allows the adjacent flared parts 54 to be partitioned so that fingers and foreign matter can be prevented from flowing.

In the embodiments of the present invention, the discharge grill 50 of the outdoor unit 1 has been described for the convenience of explanation and understanding. However, the present invention can be applied to the discharge grill 50 of the indoor unit other than the outdoor unit 1 , And it is also applicable to a suction grill in which air is sucked. Therefore, when the discharge grill according to the embodiment of the present invention is applied to an apparatus other than the outdoor unit 1, it can be defined as a fractal grill having a flectal structure.

Claims (15)

A case which forms an outer appearance and in which a blowing fan and an outdoor heat exchanger are accommodated;
And a discharge grill mounted on one side of the case to form a part of an outer tube and having a plurality of discharge ports through which the air discharged by the blowing fan passes,
In the discharge grille,
A grill core formed on one side of the discharge grill corresponding to the center of the blowing fan;
Wherein a grille portion is formed to define the discharge port by a plurality of fleet structures arranged radially with respect to the grill core.
A rim portion forming a shape of a periphery;
A circular grill core formed in a region away from the rim portion;
And a grill portion which is opened in the region between the rim portion and the grill core and through which air is passed;
Wherein the grille portion defines a plurality of apertures through which air is passed by a plurality of flectal structures disposed radially about the grill core.
3. The method of claim 2,
Wherein the plurality of fractal structures are rotatably arranged at regular intervals around the grill core.
The method of claim 3,
Wherein the plurality of fractal structures are continuously formed in a radial direction with respect to the grill core.
3. The method of claim 2,
The frac- tal structure,
A structure in which the unit shape is embedded in each corner of a unit shape formed by a pair of arcs spaced from each other around the grill core and a pair of straight lines connecting the ends of the pair of arcs is repeatedly defined Fragrance grill with characteristic.
3. The method of claim 2,
The grill portion
A mainframe portion having a plurality of edges and open;
And a subfracture portion having the same shape as that of the mainframe portion and having a smaller size at the plurality of corners.
The method according to claim 6,
Wherein the subfraxel portion includes another subfrac- tral portion having the same shape as the subfra- cle portion and having a smaller size at a plurality of corners of the subfra- cle portion.
The method according to claim 6,
The grill portion
Further comprising a plurality of concentric circular grills centered on the grill core and formed at regular intervals.
9. The method of claim 8,
Wherein the circular grill is disposed from an outer region of the grill portion to the rim portion.
The method according to claim 6,
Wherein a subframe portion closest to the grill core among the plurality of subfracture portions is in contact with an outer peripheral surface of the grill core,
And a subfrequency portion farthest from the grill core is connected to the rim portion.
The method according to claim 6,
The grill portion
And a reinforcing grille for connecting the plurality of subfraxel portions to each other.
The method according to claim 6,
The grill portion
Further comprising a straight grill connecting the grill core to the rim and radially disposed about the grill core.
In Item 12,
Wherein the linear grill defines a space between the grill core and the rim,
Wherein the frac- tal structure is provided for each of the divided spaces.
13. The method of claim 12,
Wherein the straight grille is formed between adjacent mainfrequent portions.
13. The method of claim 12,
The straight grill includes:
A first straight grill connecting between the rim portions of the grill core;
A second straight grill connecting the subframal portion closest to the grill core and the grill core among the plurality of subfracture portions;
And a third linear grille connecting the subframe portion closest to the rim portion and the rim portion among a plurality of the subfractal portions.

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