KR100833660B1 - Structure for reducing noise - Google Patents

Abstract

A noise absorbing structure is provided to facilitate installation of a noise reducer between poles by manufacturing a spiral member as long as a manufacturer wants. A noise absorbing structure comprises poles and noise reducers. The noise reducers are piled vertically between two poles, wherein each opening of the noise reducer faces the same direction. The noise reducer includes a spiral member, lateral cover members(140), a shaft member(150), and slide members(180). The spiral member has a spiral profile and spiral unit(111) with an opening(113). The lateral cover members are installed to cover two sides of the spiral member. The shaft member causes both lateral cover members to be secured to the spiral member. The slide members are attached to the outer surfaces of the lateral cover members to allow the spiral member to slide down along the poles. A sound absorbing material(120) is attached to the inner surface of the spiral member.

Description

Structure for reducing noise

1 is a front view showing that the noise reduction structure according to the first embodiment of the present invention is used as a soundproof wall,

2 is a perspective view for explaining a method for installing a noise reduction structure according to a first embodiment of the present invention;

3 is an exploded perspective view showing one noise reducer of the first embodiment of the present invention;

4 is a cross-sectional view taken along line IV-IV of FIG. 3,

5 is a front view for explaining one step of the method for manufacturing the spiral member of the first embodiment,

FIG. 6 is a front view for explaining a first method that may replace the steps shown in FIG. 5;

FIG. 7 is a front view for explaining a second method that may replace the steps shown in FIG. 5;

FIG. 8 is a front view for explaining a third method that may replace the steps shown in FIG. 5;

9 is a diagram illustrating various spirals,

FIG. 10 is an attempt of a separate yarn showing a structure for reducing noise according to a second embodiment of the present invention;

11 is a front view showing a method for bending a noise reduction structure according to a second embodiment of the present invention;

12 is a front view illustrating a method of bending a noise reduction structure according to a modification of the second embodiment.

<Description of the symbols for the main parts of the drawings>

1: road structure 2: anchor

3: support plate 4: prop

10: Noise reduction structure

100: noise reduction 110: spiral member

111: spiral 112: flat

113: opening 120: sound absorbing material

130: front filtration member 140: side shield member

150: core member 180: insertion member

300: structure for noise reduction 310: unit spiral portion

311: opening 312: opening projection part

313: roll portion 320: side shielding member

330: forward filtration member

The present invention relates to a noise reduction structure, and more particularly, to a noise reduction structure that can be used for a soundproof wall installed at a boundary of a road or the like, an engine hood covering an engine room of a vehicle, and the like.

As the quality of life is important in recent years, the necessity of noise reduction is not limited to a specific product group, but is emphasized in common for products having different technical fields such as soundproof walls and engine hoods.

However, until now, the noise reduction means has been made of a hole in a predetermined frame and filled with a porous material therein, which has been problematic in that the effect of the noise reduction is not sufficient.

In addition, the existing noise reduction means has to be designed in accordance with the appearance of the part in order to be mounted on a non-flat part of the frame is solid, and there has been a problem that must be manufactured according to the intended use.

In order to solve the above problems, an object of the present invention is to provide a structure for noise reduction significantly improved noise reduction effect.

In addition, an object of the present invention is to provide a structure for reducing noise that can be easily mounted to a non-flat portion.

Furthermore, an object of the present invention is to provide a structure for reducing noise, the cost of manufacturing is reduced.

In order to achieve the above object, the present invention comprises: at least two struts fixed to the ground; And noise reducers interposed between two adjacent struts, the struts being stacked in an extended direction, each opening being opened in the same direction.

The noise reduction device includes: a spiral member having a spiral cross section and including a plate-shaped spiral portion having an opening; Two side shielding members shielding both side portions of the spiral member; A center member disposed inside the spiral member and closely contacting the two side shielding members to the spiral member; And an insertion member fixed to an outer surface of each of the side shield members and mounted to the support.

It is preferable that a sound absorbing material is attached to the inner surface of the spiral portion.

The inner end of the helical member is preferably fixed to the central material.

Through-holes are formed in the side shielding member, the center member is disposed in the through-hole, and screws are formed at both ends of the center member, and nuts are fastened to both ends of the center member having the screw. It is preferable that the shielding member is in close contact with both sides of the helical member.

The noise reduction structure may further include a front filtration member that prevents foreign matter from flowing into the spiral portion but allows the inflow of noise.

Preferably, the post is an H beam, and the insertion member is inserted into a groove of the H beam.

The insertion member preferably includes a peripheral portion fixed to the outer surface of the side shielding member, and a central portion inserted into the groove of the H beam.

The pillar is preferably fixed to the ground via a road structure, an anchor embedded in the road structure, and a support plate fixed to the road structure by the anchor.

In order to achieve the above object, the present invention is a noise reduction structure comprising a plate-shaped unit spiral portion having an opening having an overall spiral-shaped cross section,

Each of the unit spiral parts may include: an opening projection part facing the opening; And a roll-shaped roll part, wherein the unit spiral parts are disposed in parallel to each other such that their respective openings are opened in the same direction, and the opening projection part of the unit spiral part disposed inside is a roll part of another adjacent unit spiral part. Formed integrally with, provides a structure for reducing noise.

The sound absorbing material is preferably fixed to the inner surface of the opening projection portion and the outer surface of the roll portion.

The noise reduction structure may further include a front filtration member to prevent foreign substances from flowing into the unit spiral portion but to allow the inflow of noise.

The unit spiral parts are preferably formed integrally by extrusion molding.

The noise reduction structure may further include two side shielding members that shield both sides of the unit spiral portions.

Both side portions of the unit spiral portions are preferably shielded by compression.

Hereinafter, a noise reduction structure according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 9.

The noise reduction structure 10 according to the first embodiment is interposed between at least two struts 4 fixed to the ground and two adjacent struts 4, and the struts are stacked in an extended direction. Each of the openings 113 includes the noise reducers 100 opened in the same direction.

The struts are fixed to the ground directly or indirectly. In this embodiment, the struts are road structures 1, anchors 2 embedded in the road structures, and support plates 3 fixed to the road structures by the anchors. Although shown as being fixed to the ground via the media, it is not limited thereto. In addition, in the present embodiment, the post 4 is illustrated as an H beam, but the present invention is not limited thereto.

The noise reducer 100 according to the present embodiment includes a spiral member 110 including a plate-shaped spiral portion 111 having a spiral shape as a whole, and two shielding both sides of the spiral member. Side shield members 140 and a central member 150 disposed inside the helical member and closely contacting the two side shield members to the helical member. The helical member 110 may further include a flat portion 112 as needed, and the noise reduction device may further include a front filtration member 130 and a sound absorbing material 120, as necessary. Hereinafter, an embodiment of a noise reduction device provided with all of them will be described.

The spiral part 111 of the spiral member 110 of the noise reducer 100 according to the present embodiment is a plate-shaped member having a spiral shape. As the types of spirals, the Archimedean spirals (a), log spirals (or isometric spirals) (b), hyperbolic spirals (or inverse spirals) (c), litus spirals (d), and the like shown in Fig. 9 are typical (Source: Encyclopaedia). Britannica, lnc.). The spiral part 111 of this embodiment is similar to the one cut off part of the litus spiral d, but the specific cross-sectional shape of the spiral part 111 of the present invention is not limited thereto. Alternatively, the modified shape of the specific spiral may be adopted as the specific cross-sectional shape of the spiral portion 111. In addition, a structure that forms a spiral structure as a whole by successively connecting flat plates or plates having a curved surface also belongs to a form of the spiral member 110.

The flat portion 112 extends from the outer end portion 111b of the spiral portion 111 and has a substantially flat shape. The outer end portion 111b of the spiral portion 111 has a spiral portion adjacent to the point C. It is the end. The point C, which is the boundary between the spiral portion 111 and the flat portion 112, moves from the inner end portion 111a of the spiral portion toward the outside along the cross section of the spiral portion, and the radius of curvature rapidly changes and the radius of curvature rapidly changes. This is the point that is close to infinity. On the other hand, the fact that the flat portion 112 is substantially flat is not limited to being absolutely flat (in the case of the present embodiment) of all parts along the cross section, and the overall flat portion 112 is more than the spiral portion 111 even if the flat portion is slightly bent. If less bent, this is considered to be the case.

Such a flat portion 112 is intended to reduce as much noise as possible by expanding the area of the opening 113, which will be described later, into the spiral portion 111, but may be separately manufactured and combined with the spiral portion 111. It is preferable to manufacture integrally with a spiral part like a present Example from a cost reduction viewpoint.

Referring to Figure 5 will be described a method of manufacturing the spiral member 110 from a metal plate, such as aluminum plate, galvanized steel sheet. First, when a metal plate having a predetermined width and length is prepared, the sound absorbing material 120 is preferably attached to the inner side in advance, and then the inner side of the spiral portion is formed on the rotating shaft 190 in which the groove corresponding to the thickness of the metal plate is formed in the longitudinal direction. The part to be the end portion 111a is pressed. After that, the metal plate is placed on a solid plane P and the rotating shaft 190 is rotated in the A direction as shown in FIG. 5, so that the metal plate is wound on the rotating shaft 190 to remove the rotating force applied to the rotating shaft after rotating only the required number of rotations. When the metal plate wound on the rotating shaft is released by a certain amount by elasticity has a form shown in FIG. After that, when the metal plate is removed from the rotating shaft 190, the spiral member 110 is obtained. By adjusting the material, thickness, number of windings, and the like of the metal plate, a spiral member 110 having a desired cross-sectional shape can be obtained.

It is also possible to produce the spiral member 110 shown in FIG. 4 by the extrusion molding method. In this case, it is preferable to use a synthetic resin rather than to manufacture the spiral member 110 from metal in terms of cost.

In any case of manufacturing the spiral member 110 by winding and unwinding a metal plate or by extrusion molding, one spiral member 100 can be manufactured to a length of several meters (length in Y and -Y directions). Therefore, it is possible to place only one noise reduction unit 100 between the two struts (2), and thus the noise reduction formed by manufacturing and assembling 10 to 20 noise reduction units 11 as in the conventional case. Compared to the case where the winding 10 is mounted on the soundproof wall 5, the assemblability and the mountability are improved.

On the other hand, since the spiral member has a spiral cross section as described above, the noises N4 and N5 introduced through the opening 113 are induced to the inside of the spiral member 110, and the induced noises offset each other. This causes a significant amount of the incoming noise to be extinguished. In particular, the noise (N4, N5) is guided to the inside of the helical member 110 is a point that is markedly different from the conventional noise reduction unit. In particular, unlike Japanese Patent No. 3616623, the central portion 150 is disposed on the inner side of the helical member (part from the inner end 111a to the point rotated 360 degrees along the helical member). As a result, the noise is reflected more, so that the amount of reduction due to noise interference is more.

In order to further reduce the noise introduced into the helical member 110, the sound absorbing material 120 may be attached to the inner surface 111c of the spiral portion 111 and the inner surface 112c of the flat portion 112. . In this case, some of the noises N3, N4, and N5 are absorbed and extinguished by the sound absorbing material 120, and some of them are extinguished by the offset interference action of the spiral member 110 described above. As the sound absorbing material, for example, a porous part formed of a synthetic resin material such as polyester may be used, but is not limited thereto. Any member having a noise reduction effect may be used. In particular, compared with the conventional sound absorber with sound absorbing material, the sound absorber according to the present invention has a large area (inner surface of the spiral member 110) to which the sound absorbing material is attached, so that the sound absorbing performance is remarkably superior to the conventional sound absorbing material. .

The opening 113 shown in FIG. 3 is an entrance through which noise enters into the helical member 110. The opening 113 in this embodiment is the outer end 112a of the flat portion and the spiral 111 closest thereto. Is defined by the outer surface 111d of the helical portion, and is defined by the outer end 111b of the spiral portion and the outer surface 111d of the spiral portion closest to the spiral portion when there is no flat portion. The directions of the noise reducers are determined in relation to the opening 113, where the noise reducers of this embodiment are arranged and stacked such that their respective openings open in the same direction.

The width W2 of the opening is determined by the width W1 of the flat portion 112, in principle, the length from the point C to the outer end 112a of the flat portion, but the length is 20 cm or less or there is no flat portion. 50% to 200% of the width (W2) is less than 50% of the width (W1) is less than the amount of noise flowing into the inside of the spiral member 110 is less noise This is because the reduction effect is weakened, and when the width W2 exceeds 200% of the width W1, the wind load in the lateral direction, which the noise reduction device 100 receives, becomes too large and structural stability becomes weak.

It is preferable that the front filtration member 130 is provided at a position adjacent to the opening 113. The front filtration member 130 is for preventing foreign substances from flowing into the helical member 110. Since the noise may be reflected to the road side by the front filtration member 130 when the noise is introduced into the spiral member 110, the front filtration member 130 should have as many perforations as possible to minimize this. When defining the percentage of the area of the perforated portion 130a of the entire area of the front filtration member 130 (except for the lower portion 131 and the upper portion 132, which is a portion for coupling with the spiral member), the aperture ratio is Preference is given to 10% to 99.99%.

As can be seen from FIG. 4, the front filtration member 130 of the present embodiment is illustrated as being coupled to the helical member 110 by bolts and nuts, but the method of coupling is not limited thereto. May be combined.

Meanwhile, in the present embodiment, the front filtration member 130 has a plate shape, but is not limited thereto. That is, the front filtration member may have a shape such as a bar, a rod, a wire, a mesh, and the like, as long as it can prevent the inflow of foreign substances.

Both side portions (the ends of the Y and -Y directions) of the helical member 110 are open, the noise reducer 100 is preferably further provided with a side shielding member 140 for shielding it. The bent portion 141 is formed around the side shielding member 140 of the present embodiment, which surrounds the circumferential portion of the side of the spiral member 110 and the front filtration member 130 so that the side shielding member is centered on the Y axis. This is to prevent rotation. The side shielding member 140 has a function of preventing foreign matter from flowing into the spiral member 110, similar to the front filtration member 130, and close contact with the spiral member 110, thereby preventing the noise of the spiral member 110. Suppresses the vibration to perform the function of maximizing the noise reduction effect of the spiral member (110).

The side shielding member 140 may be fixed to the spiral member 110 and / or the front filtration member 130 by welding, riveting, screwing, etc. In this embodiment, the spiral member using the central member 150. Two side shielding members 140 disposed on both sides of the 110 are fixed to each other. That is, the through hole 140a is formed in the side shield member, and the central member 150 penetrates the through hole and is disposed in the helical member, and then the nut is formed on both ends 151 of the central member 150. By tightening and fastening the 160, the two side shielding members 140 are tightly fixed to the spiral member 110. The core member 150 may have a rod-shaped center and a pipe of which the center is empty.

The insertion member 180 is fixed to an outer surface of each of the side shielding members 140 (a left side of the side shielding member on the left side of FIG. 3, a right side of the side shielding member on the right side of FIG. 3). This is to mount the noise reducer on the support 4. That is, the insertion member 180 includes a peripheral portion 182 fixed to the outer surface of the side shield member and a central portion 181 inserted into the groove of the pillar (H beam), so that the installation of noise reduction for the pillar is easy. It is to make it. However, when the central portion 181 of the insertion member does not have to fit snugly in the groove of the support, and there is a slight gap between the inner surface of the groove and the outer surface of the central portion 181, the elastic clip may be used. By elastically biasing the central portion 181 in one of the front (X direction) and the rear of the support, the noise reduction device can be stably mounted on the support.

On the other hand, the above is illustrated as separating the rotating shaft 190 and arranging the central member 150 after the specific shape of the spiral member 110 is completed, but after the specific shape of the spiral member is obtained without removing the rotating shaft 190 This may be used as the central material 150. As a result, the manufacturing process can be shortened, thereby reducing the cost and time required for manufacturing. The inner end portion 111a of the spiral member is fixed to the central member 150 to further suppress vibration of the spiral member, thereby improving noise reduction. This has the advantage of being available.

Similarly, a metal plate including slots spaced apart from each other along the longitudinal direction, a pipe-shaped central material 250 (see FIG. 6) having a somewhat thicker thickness, and protrusions 111a corresponding to the slots are prepared. Subsequently, in a state in which the protruding portion 111a of the metal plate is inserted into the slots, the core member 250 is rotated by a predetermined amount as shown in FIG. Can be obtained. In this case, there is an advantage that it can reduce the cost and time, and other matters that are not described separately with respect to the center material 250 is the same as the matter for the center material 150.

As the center member 250 shown in FIG. 6, a thick pipe should be used, which is inserted so that the end portion 111a of the metal plate faces the center of the center member 250, as shown in FIG. It is for fixing. However, when the end portion 111a of the metal plate is bent in the direction opposite to the rotation direction A, as shown in FIG. 7, the end portion 111a does not fall out of the center member 350 even during rotation due to the bending. As the core member 350, a standard pipe having a conventional thickness can be adopted. Other matters that are not described separately with respect to the center member 350 are the same as those for the center member 250.

In order to prevent the end portion 111a of the metal plate from being detached from the center member 250, the center member 450 illustrated in FIG. 8 may be adopted. The center member 450 has a protrusion 450a. When the end 111a and the protrusion 450a are fastened by riveting, screwing, welding or the like, the end 111a is completely prevented from falling out. Other matters that are not described separately regarding the center member 450 are the same as those of the center member 250.

Hereinafter, referring to FIGS. 10 to 12, a second embodiment of the present invention will be described in detail based on differences from the first embodiment.

The noise reduction structure 300 according to the second embodiment includes the unit spiral portions 310, each of which has a plate shape having a spiral cross section as a whole and has a spiral shape, and thus an opening is formed at an outer end of the spiral. 311 is formed. The unit spiral portions 310 are arranged in parallel with each other so that each of the openings 311 are opened in the same direction.

As shown in FIG. 10, each of the unit spiral portions 310 includes an opening projection portion 312 facing the opening 311 and a rolled portion 313 having a roll shape. The part 312 is a part of the unit spiral part itself, and means the part where the light is formed when the light is projected toward the opening, and the roll part 313 is a part of the unit spiral part which is not an opening projection part, and is a part which is dried. .

The noise reduction structure 300 according to the present exemplary embodiment includes unit spiral parts 310 that are stacked and integrally formed in a line, which is disposed inside the unit spiral parts (the uppermost and the lowest in FIG. 10). It is meant that the opening projection 312 of the other unit spiral portions excluding the arranged unit spiral portion is integrally formed with the roll portion 313 of the other adjacent unit spiral portion (directly above or below in FIG. 10).

The unit spiral parts integrated as described above may be manufactured by extrusion molding, and a high pressure molding material (plastic, metal, etc.) is formed through a frame in which a slit is formed in the cross-sectional shape of the unit spiral parts in the XZ plane of FIG. 10. Cooling while discharging) can be produced. However, the present invention is not limited thereto. For example, individually manufactured unit spiral parts may be manufactured in a form similar to that of FIG. 10 by gluing, welding, or fitting, to be within the scope of the present invention.

The noise reduction structure manufactured as described above exhibits excellent noise reduction effect due to offset interference of the noise introduced through the opening 311 in the unit spiral portion. In addition, when the sound absorbing material 340 is fixed (attached) to the inner surface 312a of the opening projection part and the outer surface 313a of the roll part, the sound absorbing material 340 shows an improved noise reduction effect. It can be fixed to the inner surface 312a of the opening projection part and the outer surface 313a of the roll part by being sprayed toward the rear from the X side) and then drying.

In this embodiment, the front filtration member 330 is preferably disposed at the front (X side) of the unit spiral parts to prevent foreign substances from flowing into the unit spiral parts. For example, the front filtration member 330 may include a central portion 331 formed of a mesh and a peripheral portion 332 fixed to the unit spiral by adhesion.

If the sides (parts in the Y-direction and the opposite direction) of the unit spiral portions 310 are open, the noise introduced through the opening 311 is lost to the side before the noise is eliminated, so that the noise reduction effect is lowered. It is desirable to be clogged.

10, the side portion is illustrated as being blocked by the side shield member 320, the side shield member is fixed to the unit spiral by a bolt or nail.

The noise reduction structure according to the present embodiment has a flat shape as shown in FIG. 10, but the extrusion molding material is made of a metal having excellent ductility and malleability such as aluminum, and the like. As shown in the figure, the pressing member 371 and 372 may be deformed into a desired shape by being pressed by the press members 371 and 372. Such deformability is a matter that is significantly different from the conventional noise reduction structure.

Since a lot of noise is generated in the engine of the vehicle, in order to reduce noise in the engine room, a sound absorbing material is conventionally attached to the bottom of the engine hood to reduce the noise. However, by such means, the noise reduction effect was small, which is one motivation of the present invention. However, the bottom of the engine hood is provided with reinforcing bars (bar) for reinforcing the strength of the engine hood, the arrangement of the reinforcing bar is different from vehicle to vehicle manufacturers to replace the conventional noise reduction structure engine hood There was a technical limitation to the installation on the bottom.

However, in the present embodiment, the noise reduction structure may be made of a material having excellent ductility and malleability, such as aluminum. Therefore, when the portion P1 of the structure is deformed by the pressure as shown in FIG. 11 and installed under the engine hood, the above-described excellent noise reduction effect can be obtained in reducing the noise of the vehicle. A portion P1 of FIG. 11 is a portion where the reinforcing bar is to be arranged.

Next, a modification of the second embodiment will be described with reference to FIG. 12. In the present modified example, the side shield member is shielded by pressing the side 310a of the unit spiral portions in the above-described pressing process without fixing the side shielding member to the sides of the unit spiral portions 310. This is to improve the noise reduction effect while lowering the manufacturing cost of the noise reduction structure. In FIG. 12, 381 and 382 designate the press members, which are different from the press members indicated by 371 and 372 in that unlike in FIG. 11, they protrude to compress the sides of the unit spiral portion. Meanwhile, in FIG. 12, portions P2 and P3 on which reinforcing bars are to be arranged are shown differently from FIG. 11, which is a reinforcing bar (a reinforcing bar is just an example, and at a part where a noise reduction structure is to be installed). The portion to be placed) may be simply to vary depending on the selection of the press member.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

According to the present invention, there is provided a structure for reducing noise, which is significantly improved noise reduction effect.

In addition, according to the present invention, there is provided a structure for reducing noise, which can be easily mounted on a non-flat portion.

Furthermore, according to the present invention, there is provided a structure for reducing noise, the cost required for manufacturing is reduced.

Furthermore, according to the present invention, there is provided a structure for reducing noise, which is advantageous for hygiene because foreign matters do not flow into the interior.

Claims (14)

At least two struts fixed to the ground; And A noise reduction structure interposed between two adjacent struts, wherein the struts are stacked in an extended direction and each opening is opened in the same direction. The noise reduction is: A spiral member having a spiral cross section as a whole and including a plate-shaped spiral portion having an opening; Two side shielding members shielding both side portions of the spiral member; A center member disposed inside the spiral member and closely contacting the two side shielding members to the spiral member; And And an insertion member fixed to an outer surface of each of the side shield members and mounted to the support. The method of claim 1, Noise reduction structure, characterized in that the sound absorbing material is attached to the inner surface of the spiral portion. The method of claim 2, Noise reduction structure, characterized in that the inner end of the spiral member is fixed to the central material. The method of claim 3, wherein Through-holes are formed in the side shielding member, the center member is disposed in the through-hole, and screws are formed at both ends of the center member, and nuts are fastened to both ends of the center member having the screw. Noise reduction structure, characterized in that the shielding member is in close contact with both sides of the spiral member. The method of claim 4, wherein Noise reduction structure, characterized in that further comprising a front filtration member to prevent foreign matter from entering the spiral portion, but allows the introduction of noise. The method according to any one of claims 1 to 5, The strut is the H beam, the insertion member is a noise reduction structure, characterized in that inserted into the groove of the H beam. The method of claim 6, The insertion member, the noise reduction structure, characterized in that it comprises a peripheral portion fixed to the outer surface of the side shielding member, and the central portion is inserted into the groove of the H beam. The method of claim 7, wherein The strut is a structure for noise reduction, characterized in that fixed to the ground via a road structure, an anchor embedded in the road structure, and a support plate fixed to the road structure by the anchor. A noise reduction structure including a plate-shaped unit spiral portion having an overall spiral-shaped cross section and having an opening, Each of the unit spiral parts may include: an opening projection part facing the opening; And a roll portion having a roll shape. The unit spiral parts are arranged in parallel to each other so that each opening is opened in the same direction, the opening projection portion of the unit spiral portion disposed inwardly is formed integrally with the roll portion of the other unit spiral portion adjacent, noise reduction structure. The method of claim 9, Noise reduction structure, characterized in that the sound absorbing material is fixed to the inner surface of the opening projection and the outer surface of the roll portion. The method of claim 10, Noise reduction structure, characterized in that it further comprises a front filtration member to prevent foreign substances from entering the interior of the unit spiral portion, but allows the introduction of noise. The method of claim 11, The unit spiral parts are noise reduction structure, characterized in that formed integrally by extrusion of aluminum. The method according to any one of claims 9 to 12, Noise reduction structure further comprises two side shielding members for shielding both sides of the unit helix. The method according to any one of claims 9 to 12, Noise reduction structure, characterized in that both sides of the unit spiral portion is shielded by compression.

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