KR102411790B1 - Noise reducing device and cabin of construction machinery having the same - Google Patents

Abstract

The noise reduction device includes a first noise reduction unit and a second noise reduction unit. The first noise reduction unit is fixedly installed on the interior surface of the cabin ceiling of the construction machine to absorb the noise inside the cabin, is installed spaced apart from the interior surface of the cabin ceiling, and forms a first sound-absorbing air layer of a first depth from the interior surface of the ceiling a sound absorbing member. The second noise reduction unit is fixedly installed on the interior surface of the cabin ceiling so as to be adjacent to the first noise reduction unit to absorb the noise inside the cabin, is installed spaced apart from the interior surface of the cabin ceiling, and is a second sound-absorbing air layer having a second depth from the interior surface of the ceiling. and a second sound absorbing member forming a.

Description

Noise reduction device and cabin of construction machine having same

The present invention relates to a noise reduction device and a cabin of a construction machine having the same. More particularly, it relates to a noise reduction device installed inside a cabin of a construction machine and a cabin of a construction machine having the same.

Construction machinery can generate various noises during operation. The noise may be transmitted to the inside of the cabin to affect the driver, and work efficiency may be reduced. A sound absorbing material may be installed inside the cabin to remove noise inside the cabin. For example, the sound absorbing material may be a plate-shaped silencer including a nonwoven fabric.

However, since the plate-type silencer can only reduce noise having a specific frequency, there is a problem in that it cannot remove all noises of various frequencies.

In addition, the plate-type silencer is effective in removing high-frequency noise of 1 kHz or higher, but has a problem in that the noise reduction ability is poor for low-frequency noise of 1 kHz or less. Examples of the low-frequency noise include noise caused by an engine explosion cycle, noise caused by rotation of a fan, and noise caused by a cylinder operation of a hydraulic pump.

An object of the present invention is to provide a noise reduction device capable of reducing noise inside a cabin having various frequency components.

Another object of the present invention is to provide a cabin of a construction machine having the noise reduction device.

In order to achieve the above-described object of the present invention, a noise reduction apparatus according to exemplary embodiments of the present invention includes a first noise reduction unit and a second noise reduction unit. The first noise reduction unit is fixedly installed on the interior surface of the cabin ceiling of the construction machine to absorb the noise inside the cabin, is installed spaced apart from the interior surface of the cabin ceiling, and a first sound-absorbing air layer of a first depth from the interior surface of the ceiling It may include a first sound absorbing member to form. The second noise reduction unit is fixedly installed on the interior surface of the cabin ceiling so as to be adjacent to the first noise reduction unit to absorb the noise inside the cabin, is installed to be spaced apart from the interior surface of the cabin ceiling, and is a second noise reduction unit from the interior surface of the ceiling It may include a second sound-absorbing member to form a second sound-absorbing air layer of the depth.

In example embodiments, the first and second sound absorbing members may be integrally formed to form one sound absorbing member layer.

In exemplary embodiments, the noise reduction device may further include a partition wall for partitioning the first and second sound-absorbing air layers.

In example embodiments, the first sound absorbing member and the second sound absorbing member may have the same thickness.

In exemplary embodiments, the second noise reduction unit may further include a depth adjusting member installed on the interior surface of the cabin ceiling and configured to adjust the depth of the second sound-absorbing air layer.

In exemplary embodiments, the first depth of the first sound-absorbing air layer and the second depth of the second sound-absorbing air layer may be the same as each other.

In exemplary embodiments, each of the first and second sound absorbing members may be a nonwoven fabric.

In example embodiments, the noise reduction device may further include a third noise reduction unit. The third noise reduction unit is fixedly installed on the interior surface of the cabin ceiling so as to be adjacent to the second noise reduction unit to absorb the noise inside the cabin, is installed to be spaced apart from the interior surface of the cabin ceiling, and is a third noise reduction unit from the interior surface of the ceiling. It may include a third sound-absorbing member to form a third sound-absorbing air layer of the depth.

In example embodiments, the first noise reducing unit and the second noise reducing unit may be installed to be adjacent to each other in a first direction from the front of the cabin toward the inside of the cabin.

In example embodiments, the first noise reducing unit and the second noise reducing unit may be installed to be adjacent to each other in a second direction different from the first direction on the inner surface of the cabin.

In order to achieve another object of the present invention, the cabin of the construction machine according to the exemplary embodiments of the present invention is installed on the upper revolving body of the construction machine to provide a space for the driver to board the inside, and the front is the front glass may include a cabin frame covered by and an upper portion covered by a ceiling, and a noise reduction device that is fixedly installed on an inner surface of the ceiling to absorb noise in the interior space of the cabin frame. The noise reduction device may include a first noise reduction unit installed to be spaced apart from the interior surface of the cabin ceiling and having a first sound-absorbing member that forms a first sound-absorbing air layer of a first depth from the interior surface of the ceiling, and the first noise reduction unit A second noise reduction unit having a second sound-absorbing member that is fixedly installed on the interior surface of the cabin ceiling so as to be adjacent to, and is installed spaced apart from the interior surface of the ceiling and forms a second sound-absorbing air layer of a second depth from the interior surface of the ceiling. may include

The noise reduction device according to exemplary embodiments may include a plurality of sound-absorbing air layers therein. The sound-absorbing air layers contain air, and can absorb low-frequency noises of 1 kHz or less generated in construction machines. At this time, by adjusting the thickness of the sound-absorbing air layers can be reduced at the same time noise having various frequencies. Accordingly, it is possible to increase the work efficiency of the driver.

However, the effects of the present invention are not limited to the above-mentioned effects, and may be variously expanded without departing from the spirit and scope of the present invention.

1 is a side view showing a construction machine.
FIG. 2 is a perspective view illustrating the cabin of FIG. 1 ;
3 and 4 are cross-sectional views illustrating noise reduction devices according to exemplary embodiments.
5 is a cross-sectional view illustrating an apparatus for reducing noise according to exemplary embodiments.
FIG. 6 is a graph illustrating a degree to which noise is reduced when the noise reduction device of FIG. 5 is used.
7 is a cross-sectional view illustrating an apparatus for reducing noise according to exemplary embodiments.
8 is a cross-sectional view illustrating an apparatus for reducing noise according to exemplary embodiments.

With respect to the embodiments of the present invention disclosed in the text, specific structural or functional descriptions are only exemplified for the purpose of describing the embodiments of the present invention, and the embodiments of the present invention may be embodied in various forms and the text It should not be construed as being limited to the embodiments described in .

Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle. Other expressions describing the relationship between elements, such as "between" and "immediately between" or "neighboring to" and "directly adjacent to", etc., should be interpreted similarly.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate that the described feature, number, step, operation, component, part, or a combination thereof exists, but one or more other features or numbers , it is to be understood that it does not preclude the possibility of the existence or addition of steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted to have meanings consistent with the context of the related art, and are not to be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. .

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and repeated descriptions of the same components are omitted.

1 is a side view showing a construction machine. FIG. 2 is a perspective view illustrating the cabin of FIG. 1 ; 3 and 4 are cross-sectional views illustrating noise reduction devices according to exemplary embodiments. At this time, FIG. 3 is a partial cross-sectional view of the cabin of FIG. 2 taken along line A-A', and FIG. 4 is a partial cross-sectional view of the cabin of FIG. 2 taken along line B-B'.

1 to 4 , the construction machine 10 may include an upper revolving body 20 , a lower traveling body 30 and a cabin 40 .

The upper slewing body 20 may include an engine, a boom, an arm, a bucket, various hydraulic cylinders and counterweights, and the like. The upper slewing body 20 is mounted on the lower traveling body 30, rotates on a plane parallel to the ground to set the working direction, and operates the boom, the arm and the bucket by the hydraulic cylinder to perform the work can be done In this case, it is possible to maintain the balance of the construction machine 10 in operation by using the counter weight.

The lower traveling body 30 may support the upper revolving body 20 and the cabin 40 , and the construction machine 10 may be driven by using the power generated from the engine.

The cabin 40 is installed on the upper revolving body 20 , and a driver can ride therein to control the construction machine 10 . 2 and 3 , the cabin 40 includes a frame 100 constituting a skeleton, a glass 300 covering the front of the cabin 40 , and a ceiling 200 covering the upper portion of the cabin 40 . ), a side door 400 covering the side of the cabin 40 , and a noise reduction device 500 installed on the inner surface of the ceiling 200 . In addition, various control devices for controlling the upper revolving body 20 and the lower traveling body 30 may be provided inside the cabin 40 .

The driver can enter and exit the cabin 40 through the side door 400 installed on the side of the cabin 40 and view the outside through the front glass 300 installed in front of the cabin 40 . For example, the front glass may be a light-transmissive glass or acryl.

The front glass 300 may include a detachable lower glass 310 and an upper glass 320 . The lower glass 310 and the upper glass 320 may be removed as necessary. For example, the upper glass may be separated from the frame and fixed to the ceiling, and the lower glass may be detachable from the frame. Accordingly, the front of the cabin 40 may be opened.

The noise reduction device 500 is installed on the inner surface of the ceiling 200 of the cabin 40 , and may reduce noise generated from the construction machine 10 and transmitted into the cabin 40 . In particular, it is possible to reduce not only noise in a high-frequency region having a frequency of 1 kHz or more but also noise in a low-frequency region having a frequency of 1 kHz or less.

In example embodiments, the noise reduction device 500 includes an upper panel 510 fixed to the inner surface of the ceiling 200 , a sidewall 520 extending from the upper panel 510 in a third direction, and a first partition wall. 540, a first sound-absorbing member 530 that covers one end surface of the sidewall 520 and the first partition wall 540 to form first and second sound-absorbing air layers 560 and 562 therein, and an upper panel A first adjustment member 550 installed between the 510 and the second sound-absorbing air layer 562 may be included.

The upper panel 510 may contact the inner surface of the ceiling 200 of the cabin 40 . The upper panel 510 may fix the noise reduction device 500 to the ceiling 200 , and the first and second sound absorption along with the side wall 520 , the first sound absorbing member 530 , and the first partition wall 540 . Air layers 560 and 562 may be defined.

In example embodiments, the upper panel 510 may be integrally formed with the ceiling 200 or may be removed. In this case, the side wall 520 and the first partition wall 540 may be formed to extend from the ceiling 200 in the third direction.

The sidewall 520 may extend in the third direction along the outer circumferential surface of the upper panel 510 to surround the first and second sound-absorbing air layers 560 and 562 . For example, the third direction may be a direction from the inner surface of the ceiling toward the inside of the cabin.

One end of the sidewall 520 may contact the upper panel 510 and the other end may contact the first sound absorbing member 530 . The sidewall 520 may define first and second sound-absorbing air layers 560 and 562 together with the upper panel 510 , the first sound-absorbing member 530 , and the first partition 540 . In example embodiments, the sidewall 520 may be integrally formed with the upper panel 510 .

The first sound absorbing member 530 may extend in the first direction to completely cover one end surface of the sidewall 520 . For example, the first direction may be perpendicular to the third direction and may be a direction from the front of the cabin toward the inside of the cabin. An upper surface of the first sound absorbing member 530 may contact the sidewall 520 and the first partition wall 540 , and a bottom surface of the first sound absorbing member 530 may be exposed toward the interior of the cabin 40 . In this case, the first sound absorbing member 530 may have a first thickness T1.

The first sound absorbing member 530 may be spaced apart from the upper panel 510 by the sidewall 520 and the first partition wall 540 . Accordingly, a hollow (not shown) may be formed between the upper panel 510 and the first sound absorbing member 530 . Air may be accommodated in the hollow, and may be divided into a first sound-absorbing air layer 560 and a second sound-absorbing air layer 562 by the first partition wall 540 .

In exemplary embodiments, the first sound-absorbing member 530 includes a first sub sound-absorbing member (not shown) that covers the first sound-absorbing air layer 560 and a second sub-second sub that covers the second sound-absorbing air layer 562 . It may include a sound-absorbing member (not shown). In this case, the first and second sub sound absorbing members may be integrally formed to form one sound absorbing member layer, and the sound absorbing member layer may be the first sound absorbing member 530 . In addition, when the first and second sub sound absorbing members have the same thickness, the first sound absorbing member 530 may have a uniform thickness T1 .

In example embodiments, the first sound absorbing member 530 may be a nonwoven fabric. The nonwoven fabric binds fibers together through mechanical, chemical or heat treatment, and is also referred to as a bonded fabric. The nonwoven fabric may reduce noise inside the cabin 40 . For example, the nonwoven fabric having a thickness T1 of 4 cm may reduce noise in a high frequency region having a frequency of 1 kHz or more.

The first partition wall 540 may extend from the bottom surface of the upper panel 510 by the same length as the sidewall 520 in the third direction. One end of the first partition wall 540 may contact the upper panel 510 and the other end may contact the first sound absorbing member 530 . Accordingly, the first partition wall 540 may divide the hollow into a first sound-absorbing air layer 560 and a second sound-absorbing air layer 562 . In example embodiments, the first partition wall 540 may be integrally formed with the upper panel 510 .

The first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 are formed between the upper panel 510 and the first sound-absorbing member 530 and may accommodate air therein. The first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 may be surrounded by the sidewall 520 and the first partition wall 540 , respectively.

The first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 may be partitioned by the first partition wall 540 . In this case, as shown in FIG. 3 , the first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 may be spaced apart from each other in the first direction with the first partition wall 540 interposed therebetween.

Alternatively, as shown in FIG. 4, the first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 are spaced apart from each other in a second direction different from the first direction with the first partition wall 540 interposed therebetween. can For example, the second direction may be a direction perpendicular to the first direction.

The first adjustment member 550 may be installed between the second sound-absorbing air layer 562 and the upper panel 510 . A top surface of the first adjustment member 550 may contact a bottom surface of the upper panel 510 , and a bottom surface of the first adjustment member 550 may contact the second sound-absorbing air layer 562 . For example, the first adjustment member may be integrally formed with the upper panel.

The first adjustment member 550 may extend from the bottom surface of the upper panel 510 in the third direction to have a first thickness S1, and thus the thickness D2 of the second sound-absorbing air layer 562 is thin. can get For example, the sum of the thickness (S1) of the first adjustment member and the thickness (D2) of the second sound-absorbing air layer may be equal to the thickness (D1) of the first sound-absorbing air layer. Accordingly, the thickness D2 of the second sound-absorbing air layer 562 may be adjusted by adjusting the thickness S1 of the first adjusting member 550 .

Noise inside the cabin 40 may be transmitted to the first sound absorbing member 530 in the form of wave energy, and may vibrate the first sound absorbing member 530 . As the first sound-absorbing member 530 vibrates, the first sound-absorbing member 530 may press the first sound-absorbing air layer 560 . The first sound-absorbing air layer 560 may include air therein, and the air may provide elastic recovery force to the first sound-absorbing member 530 . The wave energy of the noise and the elastic recovery force may act on the first sound absorbing member 530 in opposite directions to vibrate the first sound absorbing member 530 . Accordingly, a resonance phenomenon may occur in the first sound absorbing member 530 , and the first sound absorbing member 530 may absorb the wave energy to reduce noise. In this case, the frequency of the noise absorbed by the first sound absorbing member 530 may be determined using Equation 1 below.

는 공기의 음속이고,

는 공기의 밀도이다. 예를 들어, 30℃에서 공기의 음속은 350m/s이고 밀도는 1.15kg/m³ 일 수 있다. 또한, m은 제1 흡음 부재(530)의 면밀도이고, d는 흡음 공기층의 두께이다. 예를 들어, 두께가 4cm인 상기 제1 흡음 부재의 면밀도는 2kg/m²일 수 있다. 따라서, 상기 흡음 공기층의 두께를 조절함으로써 다양한 주파수를 가진 소음들을 흡수할 수 있다.here,

is the speed of sound in air,

is the density of air. For example, the speed of sound of air at 30° C. may be 350 m/s and the density may be 1.15 kg/m ³ . In addition, m is the areal density of the first sound-absorbing member 530, d is the thickness of the sound-absorbing air layer. For example, the areal density of the first sound absorbing member having a thickness of 4 cm may be 2 kg/m ² . Therefore, it is possible to absorb noises having various frequencies by adjusting the thickness of the sound-absorbing air layer.

For example, when the thickness (D1) of the first sound-absorbing air layer is 0.05m, the first sound-absorbing member may absorb a noise of about 190Hz. Alternatively, when the thickness (D2) of the second sound-absorbing air layer 562 is 0.03m, the frequency of the absorbed noise may be about 245Hz. Accordingly, the noise reduction apparatus 500 may reduce noise in a low-frequency region having a frequency of 1 kHz or less, for example, noises having frequencies of 190 Hz and 245 Hz, respectively.

As described above, the noise reduction apparatus 500 according to exemplary embodiments may reduce noises having a frequency of 1 kHz or higher by the first sound absorbing member 530 . In addition, by providing the first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 in contact with the first sound-absorbing member 530, it is possible to reduce the frequency of noise of 1 kHz or less. In this case, the first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 may reduce noises of different frequencies depending on the thickness. Therefore, by setting the thickness of the first sound-absorbing air layer 560 and the second sound-absorbing air layer 562 to be different from each other, it is possible to simultaneously reduce noises of different frequencies.

5 is a cross-sectional view illustrating an apparatus for reducing noise according to exemplary embodiments. FIG. 6 is a graph illustrating a degree to which noise is reduced when the noise reduction device of FIG. 5 is used. The noise reduction device is substantially the same as or similar to the noise reduction device described with reference to FIG. 3 except for the number of sound-absorbing air layers. Accordingly, like elements are denoted by the same reference numerals, and repeated descriptions of the same elements are omitted.

Referring to FIG. 5 , the noise reduction device 502 according to exemplary embodiments includes an upper panel 510 fixed to an inner surface of a ceiling 200 and extending in a third direction along an outer circumferential surface of the upper panel 510 . The sidewall 520, the first sound-absorbing member 530 covering one end of the sidewall 520, and the upper panel 510 extend in the third direction to partition the sound-absorbing air layers 560, 564, and 566. The first partition wall 540 and the second partition wall 542, the second adjustment member 552 installed between the upper panel 510 and the third sound-absorbing air layer 564, and the upper panel 510 and the fourth sound-absorbing wall A third adjustment member 554 installed between the air layers 566 may be included.

The first partition wall 540 may extend from the bottom surface of the upper panel 510 by the same length as the sidewall 520 in the third direction. One end of the first partition wall 540 may contact the upper panel 510 and the other end may contact the first sound absorbing member 530 . The first partition wall 540 may partition the first sound-absorbing air layer 560 and the third sound-absorbing air layer 564 .

The second partition wall 542 is spaced apart from the first partition wall 540 and may extend from the bottom surface of the upper panel 510 to the same length as the side wall 520 in the third direction. One end of the second partition wall 542 may contact the upper panel 510 and the other end may contact the first sound absorbing member 530 . The second partition 542 may partition the third sound-absorbing air layer 564 and the fourth sound-absorbing air layer 566 .

In example embodiments, the first and second partition walls 540 and 542 may be integrally formed with the upper panel 510 .

The first sound-absorbing air layer 560, the third sound-absorbing air layer 564, and the fourth sound-absorbing air layer 566 are formed between the upper panel 510 and the first sound-absorbing member 530, and can accommodate air therein. . A side surface of the first sound-absorbing air layer 560 may be surrounded by a side wall 520 and a first partition wall 540 , and the side surface of the third sound-absorbing air layer 564 is a first partition wall 540 and a second partition wall 542 . ), and the side of the fourth sound-absorbing air layer 566 may be surrounded by the second partition wall 542 and the side wall 520 . The first sound-absorbing air layer 560, the third sound-absorbing air layer 564, and the fourth sound-absorbing air layer 566 are partitioned by the first and second partition walls 540 and 542, and may be spaced apart from each other in the first direction. .

The second adjustment member 552 may be installed between the third sound-absorbing air layer 564 and the upper panel 510 . A top surface of the second adjustment member 552 may contact a bottom surface of the upper panel 510 , and a bottom surface of the second adjustment member 552 may contact the third sound-absorbing air layer 564 . For example, the second adjustment member may be integrally formed with the upper panel.

The second adjustment member 552 may extend from the bottom surface of the upper panel 510 in the third direction to have a second thickness S2, and accordingly, the thickness D3 of the third sound-absorbing air layer 564 is thin. can get For example, the sum of the thickness (S2) of the second adjustment member and the thickness (D3) of the third sound-absorbing air layer may be equal to the thickness (D1) of the first sound-absorbing air layer. Accordingly, the thickness D3 of the third sound-absorbing air layer 564 may be adjusted by adjusting the thickness S2 of the second adjusting member 552 .

The third adjustment member 554 may be installed between the fourth sound-absorbing air layer 566 and the upper panel 510 . A top surface of the third adjustment member 554 may contact a bottom surface of the upper panel 510 , and a bottom surface of the third adjustment member 554 may contact the fourth sound-absorbing air layer 566 . For example, the third adjustment member may be integrally formed with the upper panel.

The third adjustment member 554 may extend from the bottom surface of the upper panel 510 in the third direction to have a third thickness S3, and accordingly, the thickness D4 of the fourth sound-absorbing air layer 566 is thin. can get For example, the sum of the thickness S3 of the third adjustment member and the thickness D4 of the fourth sound-absorbing air layer may be equal to the thickness D1 of the first sound-absorbing air layer. Therefore, it is possible to adjust the thickness (D4) of the fourth sound-absorbing air layer (566) by adjusting the thickness (S3) of the third adjustment member (554).

The frequency of the noise absorbed by the first sound absorbing member 530 may be determined using Equation 1 above. For example, when the thickness of the first sound-absorbing air layer is 0.05m, the first sound-absorbing member may absorb a noise of about 190Hz. Alternatively, when the thickness D3 of the third sound-absorbing air layer 564 is 0.03m, the frequency of the absorbed noise may be about 245Hz. In addition, when the thickness (D4) of the fourth sound-absorbing air layer 566 is 0.01m, the frequency of the absorbed noise may be about 424Hz. Accordingly, the noise reduction apparatus 502 may reduce noise in a low-frequency region having a frequency of 1 kHz or less, for example, noises having frequencies of 190 Hz, 245 Hz, and 424 Hz, respectively.

In exemplary embodiments, the noise reduction device 502 may include more sound-absorbing air layers. 5 shows a noise reduction device 502 having three sound-absorbing air layers 560, 564, 566, but the number of sound-absorbing air layers is not limited thereto, and may include a larger number of sound-absorbing air layers as needed. have. In this case, the thickness of the sound-absorbing air layers may be variously selected according to the frequency of noise to be reduced.

Referring to FIG. 6 , noise in a low-frequency region having a frequency of 1 kHz or less may be reduced by using the noise reduction device 502 including the sound-absorbing air layers 560 , 564 , and 566 .

In FIG. 6 , the solid line represents the degree of noise reduction when the noise reduction device 502 described with reference to FIG. 5 is used, and the dotted line represents the degree of noise reduction according to the comparative example not having the sound-absorbing air layer. In this case, the comparative example may have only the sound-absorbing member without the sound-absorbing air layer.

In addition, the horizontal axis of the graph represents the magnitude (Hz) of the frequency, and the vertical axis represents the sound absorption coefficient. The sound absorption coefficient may indicate a degree to which the object absorbs energy when the energy is incident on the surface of the object. For example, if the sound absorption coefficient is 1, all incident energy may be absorbed, and if the sound absorption coefficient is 0, all incident energy may be reflected. Accordingly, the larger the sound absorption coefficient, the more acoustic energy can be absorbed and the more noise can be reduced. That is, as the lower area of the graph increases, more noise can be reduced.

As shown in FIG. 6 , in the comparative example, which is shown by a dotted line, having only a sound-absorbing member, only the frequency of the high-frequency region having a frequency of 1 kHz or more is absorbed, and the frequencies of the low-frequency region where the magnitude of the frequency is 1 kHz or less can not be absorbed .

In contrast, in the case of using the noise reduction device 502 , which is shown by a solid line, having sound-absorbing air layers 560 , 564 , and 566 , the magnitude of the frequency is 1 kHz as well as the frequency of the high-frequency region where the magnitude of the frequency is 1 kHz or more. It can absorb even frequencies in the low-frequency region below. That is, by using the sound-absorbing air layers (560, 564, 566), more noise can be removed as much as an area between the graph shown by the solid line and the graph shown by the dotted line.

Specifically, by the first sound-absorbing air layer 560, the noise having a frequency of 190Hz can be absorbed by 30%, and the noise having a frequency of 245Hz by the third sound-absorbing air layer 564 is absorbed by about 35%. And, by the fourth sound-absorbing air layer 566, the noise having a frequency of 424Hz may be absorbed by about 30%.

7 is a cross-sectional view illustrating an apparatus for reducing noise according to exemplary embodiments. The noise reduction device is substantially the same as or similar to the noise reduction device described with reference to FIG. 3 except for the thickness of the sound absorbing member and the adjustment member. Accordingly, like elements are denoted by the same reference numerals, and repeated descriptions of the same elements are omitted.

Referring to FIG. 7 , a noise reduction device 504 according to exemplary embodiments includes an upper panel 510 fixed to an inner surface of a ceiling 200 , and a sidewall 520 extending from the upper panel 510 in a third direction. ) and the first partition wall 540 , the side wall 520 , and the first sound-absorbing member 530 installed under the first partition wall 540 to form the first sound-absorbing air layer 560 , and the first sound-absorbing member 530 . ) may include a second sound-absorbing member 532 installed under the sidewall 520 and the first partition wall 540 to contact one side of the second sound-absorbing member 532 to form a second sound-absorbing air layer 562 .

In example embodiments, the upper panel 510 may be integrally formed with the ceiling 200 or may be removed. In this case, the side wall 520 and the first partition wall 540 may be formed to extend from the ceiling 200 in the third direction.

The first sound absorbing member 530 may be spaced apart from the upper panel 510 by the sidewall 520 and the first partition wall 540 . Accordingly, a first sound-absorbing air layer 560 may be formed between the upper panel 510 and the first sound-absorbing member 530 . An upper surface of the first sound absorbing member 530 may contact the sidewall 520 and the first partition wall 540 , and a bottom surface of the first sound absorbing member 530 may be exposed toward the interior of the cabin 40 . In this case, the first sound absorbing member 530 may have a first thickness T1.

The second sound absorbing member 532 may be installed side by side with the first sound absorbing member 530 in the first direction so as to contact one side of the first sound absorbing member 530 . The second sound absorbing member 532 may be spaced apart from the upper panel 510 by the sidewall 520 and the first partition wall 540 . Accordingly, a second sound-absorbing air layer 562 may be formed between the upper panel 510 and the second sound-absorbing member 532 . An upper surface of the second sound absorbing member 532 may contact the sidewall 520 and the first partition wall 540 , and a bottom surface of the second sound absorbing member 532 may be exposed toward the interior of the cabin 40 . In this case, the second sound absorbing member 532 may have a second thickness T2.

In example embodiments, the thickness T1 of the first sound absorbing member 530 may be different from the thickness T2 of the second sound absorbing member 532 . The sound absorbing members 530 and 532 may have different areal densities according to their thicknesses. That is, in the case of having the same area, if the thickness is doubled, the areal density may also be doubled. Therefore, it is possible to adjust the frequency of the absorbed noise by adjusting the thickness of the sound absorbing member.

For example, the first and second sound absorbing members may be non-woven fabric. In this case, when the thickness (T1) of the first sound-absorbing member 530 is 4cm, the areal density may be 2kg/m ² , and the second sound-absorbing member 530 has a thickness (T2) of 2.4cm, the areal density is It can be 1.2 kg/m ² . Substituting this into Equation 1, the absorbed frequencies may be 190 Hz and 245 Hz, respectively. Accordingly, the noise reduction apparatus 504 may reduce noise in a low-frequency region having a frequency of 1 kHz or less, for example, noises having frequencies of 190 Hz and 245 Hz, respectively.

As described above, the noise reduction apparatus 504 according to exemplary embodiments may reduce noises having a frequency of 1 kHz or higher by the first sound absorbing member 530 and the second sound absorbing member 532 . In addition, by providing the first sound-absorbing air layer 560 in contact with the first sound-absorbing member 530 and the second sound-absorbing air layer 562 in contact with the second sound-absorbing member 532, noises having a frequency of 1 kHz or less can also be reduced. have. In this case, noises of different frequencies may be reduced according to the thickness of the first sound absorbing member 530 and the second sound absorbing member 532 . Accordingly, by setting the thicknesses of the first sound absorbing member 530 and the second sound absorbing member 532 to be different from each other, noises of different frequencies may be simultaneously reduced.

8 is a cross-sectional view illustrating an apparatus for reducing noise according to exemplary embodiments. The noise reduction device is substantially the same as or similar to the noise reduction device described with reference to FIG. 7 except for the number of sound-absorbing air layers. Accordingly, the same reference numerals are used for the same components, and repeated descriptions of the same components are omitted.

Referring to FIG. 8 , the noise reduction device 506 according to exemplary embodiments includes an upper panel 510 fixed to an inner surface of a ceiling 200 and extending in a third direction along an outer circumferential surface of the upper panel 510 . The side wall 520 , the first partition wall 540 and the second partition wall 542 extending from the upper panel 510 by the same length as the side wall 520 in the third direction, the side wall 520 , and the first partition wall 540 . ) is installed to contact the bottom surface of the first sound-absorbing member 530, the first partition wall 540, and the second partition wall 542 to form a first sound-absorbing air layer 560 is installed to contact the bottom surface of the third sound-absorbing air layer The third sound absorbing member 534 forming the 564, and the fourth sound absorbing member 536 installed to contact the bottom surface of the second partition wall 542 and the side wall 520 to form a fourth sound absorbing air layer 566 (536) may include.

The first partition wall 540 is spaced apart from the second partition wall 542 , and may extend from the bottom surface of the upper panel 510 to the same length as the side wall 520 in the third direction. One end of the first partition wall 540 may contact the upper panel 510 and the other end may contact the first and third sound absorbing members 530 and 534 . The first partition wall 540 may partition the first sound-absorbing air layer 560 and the third sound-absorbing air layer 564 .

The second partition wall 542 is spaced apart from the first partition wall 540 and may extend from the bottom surface of the upper panel 510 to the same length as the side wall 520 in the third direction. One end of the second partition wall 542 may contact the upper panel 510 and the other end may contact the third and fourth sound absorbing members 534 and 536 . The second partition 542 may partition the third sound-absorbing air layer 564 and the fourth sound-absorbing air layer 566 .

In example embodiments, the first and second partition walls 540 and 542 may be integrally formed with the upper panel 510 .

The first sound absorbing member 530 may be spaced apart from the upper panel 510 by the sidewall 520 and the first partition wall 540 . Accordingly, a first sound-absorbing air layer 560 may be formed between the upper panel 510 and the first sound-absorbing member 530 . An upper surface of the first sound absorbing member 530 may contact the sidewall 520 and the first partition wall 540 , and a bottom surface of the first sound absorbing member 530 may be exposed toward the interior of the cabin 40 . In this case, the first sound absorbing member 530 may have a first thickness T1.

The third sound absorbing member 534 may be installed side by side with the first sound absorbing member 530 in the first direction so as to contact one side of the first sound absorbing member 530 . The third sound absorbing member 534 may be spaced apart from the upper panel 510 by the first and second partition walls 540 and 542 . Accordingly, a third sound-absorbing air layer 564 may be formed between the upper panel 510 and the third sound-absorbing member 534 . A top surface of the third sound absorbing member 534 may contact the first and second partition walls 540 and 542 , and a bottom surface of the third sound absorbing member 534 may be exposed toward the interior of the cabin 40 . In this case, the third sound absorbing member 534 may have a third thickness T3.

The fourth sound absorbing member 536 may be installed side by side with the third sound absorbing member 534 in the first direction so as to contact one side of the third sound absorbing member 534 . The fourth sound absorbing member 536 may be spaced apart from the upper panel 510 by the second partition wall 542 and the side wall 520 . Accordingly, a fourth sound-absorbing air layer 566 may be formed between the upper panel 510 and the fourth sound-absorbing member 536 . An upper surface of the fourth sound absorbing member 536 may contact the second partition wall 542 and the sidewall 520 , and a bottom surface of the fourth sound absorbing member 536 may be exposed toward the interior of the cabin 40 . In this case, the fourth sound absorbing member 536 may have a fourth thickness T4.

The frequency of the noise absorbed by the sound absorbing members 530 , 534 , and 536 may be determined using Equation 1 above. For example, when the thickness T1 of the first sound absorbing member is 4 cm, the first sound absorbing member may absorb noise of about 190 Hz. Alternatively, when the thickness T3 of the third sound absorbing member 544 is 2.4 cm, the frequency of the absorbed noise may be about 245 Hz. In addition, when the thickness T4 of the fourth sound absorbing member 536 is 0.8 cm, the frequency of the absorbed noise may be about 424 Hz. Accordingly, the noise reduction apparatus 502 may reduce noise in a low-frequency region having a frequency of 1 kHz or less, for example, noises having frequencies of 190 Hz, 245 Hz, and 424 Hz, respectively.

In exemplary embodiments, the noise reduction device 506 may include more sound-absorbing air layers. Although FIG. 8 shows the noise reduction device 502 having three sound-absorbing air layers 560, 564, 566, the number of sound-absorbing air layers is not limited thereto, and may include a larger number of sound-absorbing air layers as necessary. have. The sound-absorbing members covering the lower surfaces of the sound-absorbing air layers may also be installed in the same number as the sound-absorbing air layers, and in this case, the thickness of the sound-absorbing members may be variously selected according to the frequency of noise desired to be reduced. .

In exemplary embodiments, the noise reduction device 506 includes a fourth adjusting member (not shown) installed between the upper panel 510 and the third sound-absorbing air layer 564 and the upper panel 510 and the fourth It may further include a fifth adjustment member (not shown) installed between the sound-absorbing air layer (566).

In this case, the frequency that can be absorbed by the first sound absorbing member 530 may be adjusted by adjusting the thickness T1 of the first sound absorbing member 530 , and the thickness T3 of the third sound absorbing member 534 and the The frequency absorbable by the third sound absorbing member 534 can be adjusted by adjusting the thickness of the fourth adjusting member, and the fourth sound absorbing member 536 is adjusted to the thickness T4 and the fifth adjusting member by adjusting the thickness of the fourth sound absorbing member 534 . The frequency absorbable by the sound absorbing member 536 may be adjusted. That is, by simultaneously adjusting the thickness of the sound absorbing members and the thickness of the adjusting members, the noise reduction device 506 may select a frequency range of noise that can be reduced.

Although the above has been described with reference to the embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

10: construction machinery 20: upper revolving body
30: undercarriage 40: cabin
100: frame 200: ceiling
300: front glass 310: lower glass
320: upper glass 400: side door
500, 501, 502, 504, 506: noise reduction device
510: top panel 520: sidewall
530: first sound-absorbing member 532: second sound-absorbing member
534: third sound absorbing member 536: fourth sound absorbing member
540: first barrier rib 542: second barrier rib
550: first adjustment member 552: second adjustment member
554: third adjustment member 560: first sound-absorbing air layer
562: second sound-absorbing air layer 564: third sound-absorbing air layer
566: the fourth sound-absorbing air layer D1: the thickness of the first sound-absorbing air layer
D2: the thickness of the second sound-absorbing air layer D3: the thickness of the third sound-absorbing air layer
D4: thickness of the fourth sound-absorbing air layer S1: thickness of the first adjustment member
S2: thickness of the second adjustment member S3: thickness of the third adjustment member
T1: the thickness of the first sound-absorbing member T2: the thickness of the second sound-absorbing member
T3: the thickness of the third sound-absorbing member T4: the thickness of the fourth sound-absorbing member

Claims (11)

A first sound absorbing member that is fixedly installed on the inner surface of the cabin ceiling of the construction machine to absorb the noise inside the cabin, is installed spaced apart from the interior surface of the cabin ceiling, and forms a first sound-absorbing air layer of a first depth from the inner surface of the ceiling a first noise reduction unit having a; and
A second sound-absorbing air layer is fixedly installed on the interior surface of the cabin ceiling so as to be adjacent to the first noise reduction unit to absorb the noise inside the cabin, is installed spaced apart from the interior surface of the cabin ceiling, and has a second depth from the interior surface of the ceiling. Including a second noise reduction unit having a second sound absorbing member to form,
The second noise reduction unit is installed on the interior surface of the ceiling of the cabin, the noise reduction device characterized in that it further comprises a depth adjusting member for adjusting the depth of the second sound-absorbing air layer. The noise reduction device according to claim 1, wherein the first and second sound absorbing members are integrally formed to form one sound absorbing member layer. The noise reduction device according to claim 2, further comprising a partition wall for partitioning the first and second sound-absorbing air layers. The noise reduction device according to claim 2, wherein the first sound absorbing member and the second sound absorbing member have the same thickness. delete The noise reduction device according to claim 1, wherein the first depth of the first sound-absorbing air layer and the second depth of the second sound-absorbing air layer are equal to each other. The noise reduction device according to claim 1, wherein each of the first and second sound absorbing members includes a nonwoven fabric. According to claim 1, wherein the second noise reduction unit is fixedly installed on the inner surface of the ceiling of the cabin to absorb the noise inside the cabin, is installed spaced apart from the inner surface of the ceiling of the third surface from the inner surface of the ceiling Noise reduction device, characterized in that it further comprises a third noise reduction unit having a third sound-absorbing member that forms a third sound-absorbing air layer of the depth. The noise reduction apparatus according to claim 1, wherein the first noise reducing unit and the second noise reducing unit are installed adjacent to each other in a first direction from the front of the cabin toward the inside of the cabin. The method of claim 1, wherein the first noise reducing unit and the second noise reducing unit are installed adjacent to each other in a second direction different from the first direction from the front of the cabin toward the inside of the cabin on the inner surface of the cabin. noise reduction device. a cabin frame installed on the upper revolving body of the construction machine to provide a space for the driver to board the inside, the front is covered by the front glass and the upper is covered by the ceiling; and
and a noise reduction device that is fixedly installed on the inner surface of the ceiling and absorbs noise in the interior space of the cabin frame,
The noise reduction device,
a first noise reduction unit installed to be spaced apart from the interior surface of the ceiling of the cabin and having a first sound-absorbing member forming a first sound-absorbing air layer of a first depth from the interior surface of the ceiling; and
A second sound-absorbing member that is fixedly installed on the interior surface of the cabin ceiling so as to be adjacent to the first noise reduction unit, is installed spaced apart from the interior surface of the cabin ceiling, and forms a second sound-absorbing air layer of a second depth from the interior surface of the ceiling. Including a second noise reduction unit having,
The second noise reduction unit is installed on the inner surface of the cabin ceiling, the cabin of the construction machine, characterized in that it further comprises a depth adjusting member for adjusting the depth of the second sound-absorbing air layer.

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