JP2000335260A - Sound absorption blades for vehicle air vents - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorption blade that is simply structured, able to be made compact and excellent in noise reduction efficiency. SOLUTION: A plurality of sound absorption blades are provided in parallel adjacently to an air inlet of a cover that covers noise source such as an engine and hydraulic device and has an air inlet for ventilation. The sound absorption blades absorb noise leaking from inside the cover to outside via the air inlet. The sound absorption blades are provided with a core material 12 with reflecting characteristics of sound and sound absorption member 14 attached on both sides thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing blade for an air port in an engine room of a working vehicle.

[0002]

2. Description of the Related Art In some cases, a sound absorbing blade is provided at an air port provided in an engine room cover for cooling an engine of a work vehicle to reduce noise. For example, Japanese Patent Publication No. Sho 57-8729 discloses a conventional sound absorbing blade.
FIG. 11 and FIG. 12 show a side view and a sectional view of an air port portion of a work vehicle described in the publication, respectively. In FIG. 11, a pair of side panels 130 are arranged on the left and right sides of the engine room cover 120 of the work vehicle with respect to the vehicle front-rear direction. Each of the side panels 130 has an air port 160 for forming a passage for cooling air through the engine room cover 120. Multiple sound absorbing blades 11
0 are laterally disposed across the air port 160 at a predetermined distance from each other so as not to excessively restrict the air flow, are located at both lateral ends of the air port 160, and A pair of racks 18 erected on the inner surface
At 0,180, the sound absorbing device 100 is formed.

FIG. 12 shows an air port 160 and a sound absorbing blade 11.
0 is a cross-sectional view showing how the sound absorbing blade 110 is attached to the rack 180. The sound absorbing blade 110
A thick sound absorbing material 114 and a sound absorbing material 11 formed from a plate material
4 and a holder 112 that covers the entire circumference in the longitudinal direction. The upper leg 112a of the holder 112 has holes 116 for attachment to the rack 180 at both ends in the longitudinal direction.
The lower leg 112b of the holder 112 is a so-called punching metal having a plurality of holes 118 at substantially equal intervals over the entire surface. When the noise in the engine room passes through the ventilation passage 160a between the plurality of attached sound absorbing blades 110, a part of the noise is reduced to the lower leg 112 of the sound absorbing blade 110.
b through the plurality of holes 118, and is attenuated by the sound absorbing material 114, thereby reducing noise.

[0004]

However, in response to the recent increase in work in urban areas and residential areas and the tightening of noise regulations as a countermeasure against environmental problems, the need for further noise reduction has been increasing. . To satisfy this, it is conceivable to increase the blade shape or increase the number of blades of the sound absorbing blade 110 shown in the above-described conventional technique. There arises a problem that the cooling efficiency decreases due to a decrease in the cooling air flow due to the decrease in the cooling air flow.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a sound absorbing blade which has a simple structure, can be reduced in size, and has an excellent noise reduction effect. .

[0006]

In order to achieve the above object, a first aspect of the present invention is to provide a cover for covering a noise source such as an engine or a hydraulic device and having an air port through which outside air flows. A core material having a characteristic of reflecting sound, and both surfaces of the core material, in a sound absorbing blade of an air port of a vehicle, in which a plurality of sheets are arranged adjacent to the air port and absorb noise leaking from inside the cover to the outside via the air port. And a sound-absorbing material that is attached to the vehicle.

According to the present invention, even with a sound absorbing blade having the same thickness as that of the conventional sound absorbing material, the sound absorbing material is attached to both sides of the core material, and the sound is absorbed on both sides of the sound absorbing blade. By doing so, the sound absorbing area is doubled, and the sound absorbing effect is improved. Furthermore, since the core material is sandwiched between the sound absorbing materials from both sides, a vibration damping action works, and sound waves are attenuated by energy loss due to the vibration damping action when reflected by the core material,
Also, the sound wave emitted from the opposite surface of the core material through the core material is attenuated by the sound absorbing effect of the sound absorbing material on the opposite surface of the core material,
The sound absorbing effect is further improved. This makes it possible to manufacture a sound-absorbing blade having a simple structure and a large noise reduction effect at the air port of the vehicle even with the same size as the conventional one.

Further, in the present invention, if the core member has a mounting portion to the vehicle, the number of parts can be reduced with a simple configuration, and the mounting to the vehicle body can be made robust. Thus, a sound absorbing blade having a structure that can withstand severe vibration and impact of the vehicle can be obtained.

In the present invention, if the sound absorbing blade is provided with a cover which covers both end surfaces in the ventilation direction of the sound absorbing blade and the outer surface of which is substantially semi-cylindrical, the sound absorbing blade receives the wind on the cylindrical surface of the cover in the ventilation direction. As a result, eddy and peeling are unlikely to occur, so that ventilation resistance is small. In addition, the penetration of dust and moisture from the end surfaces of the sound absorbing material at both ends in the ventilation direction of the sound absorbing blade is prevented, thereby preventing deterioration of the sound absorbing effect. This allows
It is possible to obtain an excellent sound absorbing blade that can ensure a sufficient amount of ventilation and that has a long-lasting noise reduction effect.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2
9 shows an application example of a sound absorbing blade according to the present invention to a wheel loader. FIG. 1 is a plan sectional view of an engine room of the wheel loader 50, and FIG. 2 is a side sectional view thereof.
Air for cooling the engine 52 is sucked in from the left and right sides and upper air ports 57, 58, 59 of the engine 52, and is exhausted from the air ports 56 provided opposite to the radiator 54. A plurality of sound-absorbing blades 10 are attached to the air ports 56, 57, 58, 59 at predetermined intervals in a substantially parallel manner, and the ventilation paths 56a, 57a, 5 are respectively provided.
8a and 59a are formed.

FIG. 3 is a perspective view showing an example in which the sound absorbing blade 10 is attached to the air port 56 facing the radiator 54 of FIG. The sound absorbing blade 10 is attached to attachment members 31a and 31b that form the upper and lower surfaces of the air port 56 by bolts or the like (not shown).

Next, a first embodiment will be described with reference to FIGS. FIG. 4 shows a sound absorbing blade 10 according to the present invention.
FIG. 5 is a perspective view after assembly. As shown in FIG. 4, the sound absorbing blade 10 includes a core 12,
Two sound absorbing members 14, 14 attached to both surfaces of the core member 12, and two covers 16, 1 provided at both ends in the ventilation direction.
Consists of six.

The core member 12 is made of a sheet material such as a sheet metal, and has a U-shaped cross section in the ventilation direction, and has a sound absorbing material mounting portion 12a and upper and lower ends of the sound absorbing material mounting portion 12a from the sound absorbing material mounting surface side. Attachment part 12 which extends to each and extends
b, 12c. The size of the sound absorbing material mounting portion 12a is substantially the same as the length and width of the sound absorbing material 14, and the sound absorbing materials 14 are attached to both sides of the sound absorbing material 14 so as to overlap each other. The mounting portions 12b and 12c have a projecting amount L1 slightly larger than the thickness t2 of the sound absorbing material 14 from the sound absorbing material mounting portion 12a, and each has a mounting hole 12d for mounting to a vehicle body at a tip portion.
Having. The sound absorbing material 14 is a plate having a rectangular cross-sectional shape, and is a urethane foam having a sound absorbing function. Core material 1
The surface 14a opposite to the surface attached to 2 is treated to form a non-breathable coating so as not to deteriorate the sound absorbing characteristics. The cover 16 is formed of a plate material such as a sheet metal, and has a semi-cylindrical shape obtained by cutting a cylinder having a radius substantially equal to the thickness of the sound absorbing material 14 into approximately half along the central axis, and has a length in the longitudinal direction of the core. It is equal to the distance between the two inner surfaces of the mounting portions 12b and 12c of the material 12. As shown in FIG.
Is a contact portion 1 that is in contact with the mounting portions 12b and 12c of the core material 12.
At 6a, it is welded and fixed to the core material 12.

Next, the operation of the first embodiment will be described. First, the difference between the sound absorbing function of the prior art and the present invention will be described with reference to FIG. FIG. 6A shows FIG.
FIG. 6 is a cross-sectional view of the sound absorbing blade 110 of the prior art shown in FIG. 12, and FIG. 6 (b) is a cross-sectional view of the sound absorbing blade 10 of the present invention shown in FIG. It is a figure explaining the sound absorption effect in ventilation path 56a.

In FIG. 6A, which is a prior art, a sound wave 140b incident on the lower leg 112b of the sound absorbing blade 110 of the ventilation passage 160a is partially reflected but mostly transmitted through the hole 118 of the punching metal. The sound wave that passes through the sound absorbing material 114 while attenuating and reaches the upper leg portion 112a is reflected by the upper leg portion 112a, passes again while attenuating inside the sound absorbing material 114, and passes through the hole of the punching metal in the lower leg portion 112b. The light is emitted to the outside through 118. As a result, most of the sound wave 140b is attenuated while reciprocating inside the sound absorbing material 114, but the sound wave 140b reaching the upper leg 112a is attenuated.
As shown by a dotted arrow in FIG. 0b, a sound wave emitted to the outside via the upper leg 112a is generated. A small part of the sound wave 140a incident on the upper leg 112a of the sound absorbing blade 110 is attenuated inside the sound absorbing material 114 through the upper leg 112a as shown by a dotted arrow, but almost all of the sound wave 140a is reflected. Does not decay.

In FIG. 6B, which is an embodiment of the present invention, the surface 14 of one sound absorbing blade 10 of the ventilation passage 56a is shown.
The sound wave 40a incident on a passes through the sound absorbing material 14 while attenuating, and the sound wave 40a reaching the core 12 is almost entirely reflected, passes through the sound absorbing material 14 while attenuating again, and is emitted to the outside. Is done. As a result, the sound wave 40a is attenuated while reciprocating inside the sound absorbing material 14, and furthermore, as shown by the dotted arrow, the sound wave emitted to the opposite side without being reflected by the core material 12 is also transmitted by the opposite sound absorbing material 14. Decay. Also, the sound wave 40b incident on the surface 14a of the other sound absorbing blade 10 in the ventilation path 56a is similarly attenuated.

It is generally known that the sound absorbing area has a greater effect on the sound absorbing characteristics than the thickness of the sound absorbing material. In the present embodiment, assuming that the thickness t1 of the sound absorbing material 114 is approximately twice the thickness t2 of the sound absorbing material 14, the noise incident from the lower leg 112b in FIG. 6 (b), the noise incident from the surface 14a passes twice as thick as the sound absorbing material 14 in a reciprocating manner, and is therefore one half that of the prior art. It is. However, since sound absorbing materials are attached to both sides of the core material and sound is absorbed by the sound absorbing materials on both sides of the ventilation path 56a, the sound absorbing area is twice as large as that of the conventional technology, and therefore, the sound absorbing area is larger than the thickness of the sound absorbing material. Since the effect of the sound absorbing characteristics is larger in the area, the noise reduction effect of the embodiment of the present invention in FIG. 6B is better. Further, in FIG.
Since the sound absorbing member 2 is sandwiched between the sound absorbing members 14 from both sides, a vibration damping effect works. When the sound wave is reflected by the core member 12, the sound wave is attenuated by an energy loss due to the vibration damping effect, thereby further improving the noise reduction effect.

FIG. 7 shows data obtained by experiments by the applicant and shows the noise reduction amount of the sound absorbing blade. FIG. 7A shows data of the first embodiment of the present invention, and FIG. 7B shows data of a sound absorbing blade of a product equivalent to the prior art, in which a sound absorbing material is attached to only one side of the holder. As can be seen from the experimental results, it is possible to improve the noise reduction effect by about 2 dB as compared with the related art.

Further, since the surface 14a of the sound absorbing material 14 is treated to form a non-breathable film, dust and moisture which cause deterioration of sound absorbing characteristics are not passed through the inside of the sound absorbing material 14. The cross section of the sound absorbing material is the mounting portion 1 of the cover 16 and the core material 12.
2b, 12c and the vehicle-body-side mounting members 31a, 31b prevent dust and moisture from entering the sound absorbing material 14. As a result, it is possible to prevent the sound absorbing effect from deteriorating, and to obtain a sound absorbing blade having an excellent effect of reducing noise over a long period of time.

Further, since the sound absorbing blade 10 receives the wind on the cylindrical surface of the cover 16 in the ventilation direction, the sound absorption blade 10 is less likely to vortex or separate, so that the ventilation resistance is small. Thereby, the air volume of the cooling air can be sufficiently ensured.

The sound-absorbing blade 10 according to the first embodiment of the present invention has a simple structure in which the cover 16 is fixed to the core material 12 having the sound-absorbing material 14 attached to both sides thereof. The integrally formed mounting portions 12b and 12c enable a robust mounting to the vehicle body, and a structure having strength enough to withstand severe vibration and impact of the working vehicle can be obtained.

Furthermore, by setting each component of the sound-absorbing blade 10 as a fixed-size part, when manufacturing a sound-absorbing blade of a specific size, the fixed-size part corresponds to the type of work vehicle and the mounting location for each specification. It can be easily manufactured by cutting and bending at the specified length and height. For this reason, it is possible to easily design the sound absorbing blade while securing the degree of freedom in designing the sound absorbing blade, such as the vertical and horizontal sizes. In addition, the number of types of components does not increase due to the setting of fixed-size components, so that management is easy in component management and inventory management. Furthermore, by making a database of the vertical and horizontal size, thickness, mounting pitch, etc. of the sound absorbing blade on the basis of fixed size parts, it is possible to easily select a sound absorbing blade that satisfies the required noise reduction amount, space requirement, etc. it can.

Although the cover 16 has been described as a semi-cylindrical sheet metal, it need not be a semi-cylindrical shape as long as the ventilation resistance is small, and needless to say, may be an elliptical cylindrical shape. In addition, by attaching a sheet such as a vinyl film instead of a sheet metal, the cross section of the sound absorbing material 14 at both end surfaces in the ventilation direction of the sound absorbing blade 10 may be protected. In this case, in order to reduce the ventilation resistance of the sound absorbing material 14 in the ventilation direction, it is more preferable to form the end of the sound absorbing material 14 into a substantially semi-cylindrical shape and then attach a vinyl film.

Next, a second embodiment will be described with reference to FIGS. FIG. 8 shows a sound absorbing blade 20 according to the present invention.
Is an exploded perspective view, and FIG. 9 is a perspective view after assembly. As shown in FIG. 8, the sound absorbing blade 20 includes a core material 22,
Two sound absorbing materials 24, 24 attached to both sides of the core material 22,
Two covers 26, 26 provided at both ends in the ventilation direction
And four mounting members 28, 28, 28, 28 arranged at both ends in the longitudinal direction of the cover 26.

The core member 22 is made of a plate material such as a sheet metal. The height H1 is substantially the same as the height H2 of the sound absorbing material 24, and the length B1 is slightly longer than the length B2 of the sound absorbing material 24. Further, the core member 22 has core end portions 22a, 22a at both ends in the length direction.
a so that the sound absorbing members 24, 24
Are attached to both sides thereof. The sound absorbing material 24 is a plate having a rectangular cross-sectional shape, and is a urethane foam having a sound absorbing function. The surface 24a opposite to the surface attached to the core member 22 is treated to form a non-breathable film which does not affect the deterioration of the sound absorbing characteristics. The cover 26 is made of resin and has a semi-cylindrical shape obtained by cutting a cylinder having a radius substantially equal to the thickness of the sound absorbing material 24 in half along the central axis. It is approximately equal to the height H1. Furthermore, a slot 26a opening toward the center over the entire length in the longitudinal direction is provided at the center on the inner surface side of the cover 26.
Is provided. The opening width of the slot 26a is substantially equal to the thickness of the core member 22. The attachment member 28 is a member integrally formed of a resin having a flat attachment portion 28a and a support portion 28b erected on one surface thereof, or a member integrally formed by sheet metal welding or the like. The mounting portion 28a has a rectangular shape in which one side length L3 is slightly longer than the thickness L2 of the sound absorbing blade 20, and near the both ends in the thickness direction of the sound absorbing blade 20 is a mounting hole 28c used for mounting to a vehicle. , 28
c. The support portion 28b is a member erected at a predetermined height in an arc shape, and the inner radius of the arc is substantially the same as the outer radius of the cover 26, and is located substantially at the center of the mounting portion 28a.

The mounting member 28 may have a shape other than that shown in FIG. 8 as long as it has a supporting portion for supporting the cover 26 and a mounting portion having a mounting hole used for mounting on the vehicle body. Of course.

The sound absorbing blade 20 is assembled by the sound absorbing material 2
The cover 26 is placed on both sides of the core member 22 with the core member 4 attached to both sides so that the core end portion 22a is inserted into the slot 26a. Then, in a state shown in FIG. 9 in which the both ends in the longitudinal direction of the cover 26 and the supporting portions 28b of the mounting member 28 are in contact with each other,
Attach it to the vehicle body as shown in FIG.

Next, the operation of the second embodiment will be described. As for the noise reduction effect, as in the first embodiment, sound is absorbed on both sides of the ventilation path, so that the sound absorption area is doubled as compared with the related art, and the sound wave emitted to the opposite side of the core member 22 is opposite. Is absorbed by the sound absorbing material 24, and the core material 22 is damped by the sound absorbing material 24 attached to both sides, so that the sound absorbing effect can be improved. In the same manner as in the first embodiment, the sound absorbing blade 20 is also provided with the cover 2 with respect to the ventilation direction.
Since wind is received on the cylindrical surface of No. 6, vortices and separation do not easily occur, so that the ventilation resistance is small. Thereby, the air volume of the cooling air can be sufficiently ensured.

The sound-absorbing blade 20 according to the second embodiment of the present invention has a simple structure in which a cover 26 is attached to a core material 22 having sound-absorbing materials 24 attached to both surfaces, and the cover 26 is attached to a vehicle body using an attaching member 28. Further, the cover 26 can be firmly attached to the vehicle body by firmly sandwiching both ends in the longitudinal direction of the cover 26 with the attachment members 28, 28, and a structure having a strength capable of withstanding severe vibration and shock of the work vehicle is obtained. I can do things.

Further, for each component of the sound-absorbing blade 20, the mounting member 28 is set as a common part, and the other parts are set as fixed-size parts. It can be easily manufactured by performing cutting at a length and height corresponding to the mounting location for each vehicle model and specification. For example, as shown in FIG. 10, even when there is a step 33 on the mounting surface 31 of the sound absorbing blade 20 on the vehicle body side, the fixed-size components (the core member 22, the sound absorbing material 24, the cover 26, etc.) are cut with dimensions corresponding to the step. By doing so, you can easily respond. For this reason, it is possible to easily design the sound absorbing blade while securing the degree of freedom in designing the sound absorbing blade, such as the vertical and horizontal sizes. In addition, the types of components do not increase due to the setting of the common components and the standard-size components, and the management in the component management and the inventory management is facilitated. In addition, by making a database of the vertical and horizontal size, thickness, mounting pitch, etc. of the sound absorbing blade based on common parts and fixed size parts, it is easy to select a sound absorbing blade that satisfies the required noise reduction amount and floor space etc. can do.

In the above description of the embodiments, the sound absorbing material is not limited to urethane foam, and it is needless to say that materials having a sound absorbing effect, such as glass wool and felt, have similar functions and effects. In this case, as a method of protecting the surface, there is a method of surrounding the surface of the sound absorbing material with a glass cloth (cloth made of glass wool) and coating the surface of the glass cloth with neoprene or aluminum foil. Further, in the description of the embodiment, the core material is not limited to the sheet metal, and may be any member that reflects sound. For example, a plurality of holes are provided like a so-called punched metal to reflect most of the sound waves. Have the same action and effect. Furthermore, in the case of this perforated metal, when the sound-absorbing blade is installed, for example, in the horizontal direction, even if water enters the sound-absorbing blade, it passes through the hole, so that water is accumulated near the core material and hinders the sound absorbing effect. Can be prevented. Also,
The thickness of the sound absorbing material attached to both sides of the core may be different. Further, in the description of the embodiment, the example in which the air is discharged from the air port of the radiator section has been described. However, the same effect can be naturally obtained in a form in which the air is suctioned from the air port of the radiator section like a hydraulic shovel. is there.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing an example of application to a wheel loader as a work vehicle.

FIG. 2 is a side sectional view showing an application example to a wheel loader as a work vehicle.

FIG. 3 is a perspective view showing an example of attachment to an air port near a radiator.

FIG. 4 is an exploded perspective view of the sound absorbing blade according to the first embodiment of the present invention.

FIG. 5 is a perspective view of the sound absorbing blade according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a sound absorbing effect of the sound absorbing blade of the present invention.

FIG. 7 is a diagram showing a measurement result of a noise reduction amount of the sound absorbing blade of the present invention.

FIG. 8 is an exploded perspective view of a sound absorbing blade according to a second embodiment of the present invention.

FIG. 9 is a perspective view of a sound absorbing blade according to a second embodiment of the present invention.

FIG. 10 is a perspective view illustrating an example of attachment to a vehicle body in a case where the sound absorbing blade according to the second embodiment of the present invention has a step on an attachment surface.

FIG. 11 is a side view of a vehicle showing an application example of the related art.

FIG. 12 is a cross-sectional view of an air port showing an application example of the related art.

[Explanation of symbols]

10, 20, 110; sound absorbing blades, 12, 22; core material, 14, 24, 114; sound absorbing material, 16, 26; cover, 28; mounting member, 40a, 40b, 140a, 14
0b; sound wave, 112; holder, 180; rack.

Claims (1)

[Claims] 1. A plurality of noises covering a noise source such as an engine or a hydraulic device and having a plurality of air ports through which air is ventilated to the outside, and juxtaposed in the vicinity of the air ports, and leaking from the inside of the cover to the outside via the air ports. A sound absorbing blade at the air port of a vehicle that absorbs noise, a core material (12, 22) having a characteristic of reflecting sound, and a sound absorbing material (14, 24) attached to both surfaces of the core material (12, 22). A sound absorbing blade for an air port of a vehicle, comprising: