JP2008080992A - Noise-proof cover structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact noise-proof cover structure capable of securely reducing noise generated in a noise source device. <P>SOLUTION: The noise-proof cover structure comprises a noise-proof cover covering at least a raised part of the noise source device with the projecting raised part and a plurality of noise source side fixation parts integral with the noise source device. The noise source side fixation parts are formed in positions sandwiching the tip part of the raised part at least one by one, and the noise-proof cover is provided with a sheet-shaped cover body comprising an elastic material and with a plurality of cover side fixation parts integral with the cover main body. With the cover body extended and deformed to have a shape along the raised part, the cover side fixation parts and noise source side fixation parts are fixed to each other so that the noise-proof cover is mounted to the noise source device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a soundproof cover structure that is fixed to a device (noise source device) serving as a noise source such as an automobile transmission or an engine and covers at least a part of the noise source device.

  The soundproof cover structure that is fixed to the noise source device and covers at least a part of the noise source device has a soundproof cover that covers the noise source device and a noise source side fixing portion that is integrated with the noise source device and fixes the soundproof cover. . As a soundproof cover in this type of soundproof cover structure, a structure in which a structural layer made of a hard material such as a resin and a sound absorbing layer made of a nonwoven fabric or the like is laminated is known (for example, see Patent Document 1).

The soundproof cover introduced in Patent Document 1 has a sound absorbing layer made of a nonwoven fabric or the like. The sound absorbing layer absorbs noise radiated from the noise source device and propagating through the air (air propagation sound) and noise radiated from the noise source device and propagated to the soundproof cover (solid propagation sound). The sound absorbing layer is generally formed thick. This is to greatly reduce the noise generated by the noise source device. However, when the sound absorbing layer is thick, the soundproof cover becomes bulky. For this reason, depending on the environment in which the noise source device is disposed, a desired portion of the noise source device may not be covered with the soundproof cover. In addition, when the noise source device has a complicated shape, a gap is generated between the noise source device and the soundproof cover, and air-propagating sound passing through the gap may be emitted to the outside.
Japanese Patent Laid-Open No. 2002-221967

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a soundproof cover structure that is not bulky and can reliably reduce noise generated by a noise device.

  The soundproof cover structure of the present invention that solves the above-described problems is a noise source cover that covers at least a raised portion in a noise source device having a convex raised portion, and a plurality of noise source sides integrated with the noise source device. The noise source side fixing part is formed at least one at a position sandwiching the top part of the raised part, and the soundproof cover is made of an elastic material and forms a sheet-like cover main body, and the cover main body is integrated with the cover main body. The soundproof cover has a cover body fixing portion and a noise source side fixing portion fixed to each other in a state in which the cover body is stretched and deformed into a shape along the raised portion. It is attached to a noise source device.

The soundproof cover structure of the present invention preferably includes the following (1).
(1) The elastic material is at least one selected from chloroprene rubber, ethylene propylene rubber, and silicone rubber.

  In order to make the soundproof cover in a non-bulky shape, it is considered that the layer (sound absorbing layer) made of the above-described nonwoven fabric or the like should be eliminated. However, the soundproof cover having no sound absorbing layer and only the structural layer has only a function of shielding the air propagation sound, and the noise generated by the noise source device cannot be sufficiently reduced.

  If the entire soundproof cover is formed of an elastic material such as rubber and the soundproof cover is in close contact with the noise device, it is considered that the air-borne sound can be shielded and the solid-borne sound can be reduced by the mass (mass) effect. By the way, when the noise source device has a complicated shape, it is necessary to form the soundproof cover into a complicated shape. However, it is difficult to form a soundproof cover made of an elastic material such as rubber with high accuracy, and it is extremely difficult to eliminate a gap between the noise source device and the soundproof cover.

  The soundproof cover structure of the present invention has a plurality of noise source side fixing portions integrated with a noise source device, and a soundproof cover. The soundproof cover has a cover body made of an elastic material and has a sheet shape, and a cover side fixing portion for fixing the soundproof cover to the noise source device. In the soundproof cover structure of the present invention, since the cover body is made of an elastic material, it can be made thinner than a soundproof cover having a sound absorbing layer made of a nonwoven fabric or the like. Therefore, the soundproof cover in the soundproof cover structure of the present invention is not bulky.

  Since the cover body is made of an elastic material, it can be stretched and deformed. The soundproof cover is attached to the noise source device by fixing the cover side fixing portion and the noise source side fixing portion to each other in a state where the cover main body extends and deforms in a shape along the raised portion. For this reason, a cover main body press-contacts to the top part of a protruding part, and press-contacts or contact | adheres also to the peripheral part of a top part. Therefore, according to the soundproof cover structure of the present invention, the gap between the cover main body and the noise source device can be eliminated even though the noise source device has a complicated shape. Can be shielded reliably. Furthermore, solid propagation sound can be reduced by the mass effect of the cover body. Furthermore, since the cover main body is in pressure contact with the raised portion, the cover main body does not vibrate when the solid propagation sound propagates. Therefore, no noise is generated due to the vibration of the cover body.

  Therefore, the soundproof cover structure of the present invention is not bulky and can reliably reduce noise generated in the noise source device.

  In the case where the soundproof cover structure of the present invention includes the above (1), the solid propagating sound can be greatly reduced by the cover body, so that the noise generated in the noise source device can be more reliably reduced.

  That is, chloroprene rubber, ethylene propylene rubber, and silicone rubber are all known as high damping materials. By forming the cover main body from these high attenuation materials, the solid-propagating sound propagated to the cover main body is attenuated and does not propagate to the outside. Therefore, if the cover main body is formed of these high attenuation materials, the solid propagation sound can be greatly reduced.

  In the soundproof cover structure of the present invention, examples of the elastic material for forming the cover body include known materials such as natural rubber, various synthetic rubbers, and various elastomers. The cover body may be formed of only one of these materials, or may be formed by mixing various types. Further, in order to greatly reduce the solid-borne sound, the material forming the cover body is preferably an elastic material and a high damping material. The high damping material refers to a material having a low hardness and a low spring constant that suppresses and suppresses energy transfer by vibration propagation (solid propagation) and air propagation. As described above, since chloroprene rubber, ethylene propylene rubber, and silicone rubber are high damping materials, they are preferably used as elastic materials for forming the cover body. When the cover body is formed of silicone rubber, the solid propagation sound can be particularly greatly reduced. Silicone rubber has the largest damping coefficient among these high damping materials, and has a low hardness and a low spring constant.

  Furthermore, in order to increase the mass effect of the cover body, it is preferable to select a material (mass body) having a large mass per unit volume as the elastic material.

  In the cover main body, the length in the direction of expansion and deformation when the soundproof cover is assembled to the noise source device is preferably 105 to 130%, where the length in the state where the cover is not stretched and deformed is 100%. By extending and deforming the cover main body within this range, the cover main body can be securely adhered to the noise source device.

  The cover body in the soundproof cover structure of the present invention has a sheet shape. The cover body may have a flat sheet shape or a curved sheet shape. Moreover, the unevenness | corrugation may be formed in the surface and back surface of a cover main body. For example, the cover body may be formed into a curved sheet shape corresponding to the raised portion of the noise source device. In addition, in a noise source device having a recessed portion and a raised portion having a concave shape, when the raised portion and the recessed portion are covered with a cover body, a convex portion corresponding to the recessed portion may be formed on the cover body. Good. In this case, if the raised portion is covered with the cover main body and the convex portion is inserted into the depressed portion, the gap between the cover main body and the noise source device can be more reliably eliminated.

  The noise source side fixing portion and the cover side fixing portion may be fixed to each other by a known method such as fitting, engagement, screwing, caulking, adhesion, or the like. The noise source side fixing portion and the cover side fixing portion may be fixed so as to be removable, or may be fixed so as not to be removable.

  The soundproof cover structure of the present invention will be described below with reference to the drawings.

(Example)
The soundproof cover structure of the embodiment includes the above (1). The principal part expansion exploded perspective view which represents typically the soundproof cover structure of an Example is shown in FIG. 1, and the principal part enlarged perspective view which represents typically the soundproof cover structure of an Example is shown in FIG. FIG. 3 is a cross-sectional view schematically showing a state in which the soundproof cover structure of the embodiment is cut at the position AA in FIG.

  The soundproof cover structure of the embodiment has a noise source side fixing portion 1 and a soundproof cover 2. The soundproof cover 2 in the soundproof cover structure of the embodiment covers a part of the transmission which is a noise source device. Specifically, in the soundproof cover structure of the embodiment, the soundproof cover 2 covers the gear housing 3 that houses the gear portion in the transmission.

  As shown in FIG. 1, the gear housing 3 is formed with a raised portion 30 having a convex shape. Further, the gear housing 3 has four noise source side fixing portions 1 (a first noise source side fixing portion 11, a second noise source side fixing portion 12, a third noise source side fixing portion 13, and a fourth noise source side fixing portion 13 having a protruding shape. A noise source side fixing portion 14) is formed. The first noise source side fixing portion 11 and the second noise source side fixing portion 12 are arranged on one side (left side portion in FIG. 1) of the gear housing 3 with the top portion 300 of the raised portion 30 sandwiched therebetween. Has been. The third noise source side fixing portion 13 and the fourth noise source side fixing portion 14 are arranged while being separated from each other on the other side (right side portion in FIG. 1) sandwiching the top portion 300 of the raised portion 30. In the soundproof cover structure of the embodiment, each noise source side fixing portion 1 has a columnar leg portion 100 extending from the gear housing 3 and a head having a larger diameter than the leg portion 100 and formed at the tip of the leg portion 100. 101.

  The soundproof cover 2 includes a cover main body 20 and four cover side fixing portions 21 having a through-hole shape (first cover side fixing portion 211, second cover side fixing portion 212, third cover side fixing portion 213, and fourth cover. Side fixing part 214). The cover body 20 is made of silicone rubber, which is an elastic material and a high damping material, and has a flat sheet shape. Each cover side fixing | fixed part 21 makes a through-hole shape. The first cover side fixing portion 211 and the second cover side fixing portion 212 are arranged while being separated from each other at one end portion of the cover main body 20 (referred to as the left end portion in FIG. 1 and the first end portion 25). The third cover side fixing portion 213 and the fourth cover side fixing portion 214 are arranged on the other end portion of the cover body 20 (referred to as the right end portion in FIG. 1 and the second end portion 26) while being separated from each other. Yes. The distance L1 between the first cover side fixing portion 211 and the third cover side fixing portion 213 is smaller than the distance L2 between the first noise source side fixing portion 11 and the third noise source side fixing portion 13 on the surface of the gear housing 3. . A distance L3 between the second cover side fixing portion 212 and the fourth cover side fixing portion 214 is smaller than a distance L4 between the second noise source side fixing portion 12 and the fourth noise source side fixing portion 14 on the surface of the gear housing 3. .

  When the soundproof cover 2 in the soundproof cover structure of the embodiment is attached to the gear housing 3, the operator first holds the first end 25 and the second end 26 of the cover body 20, and first end The cover main body 20 is extended and deformed in a direction in which 25 and the second end portion 26 are separated from each other. Next, the first noise source side fixing portion 11 is inserted through the first cover side fixing portion 211, the second noise source side fixing portion 12 is inserted through the second cover side fixing portion 212, and the third cover side fixing portion 213 is inserted. The third noise source side fixing portion 13 is inserted, and the fourth noise source side fixing portion 14 is inserted into the fourth cover side fixing portion 214. In each noise source side fixing portion 1 and each cover side fixing portion 21, the leg portion 100 of the noise source side fixing portion 1 is accommodated in the cover side fixing portion 21, and the head portion 101 is exposed to the outside of the cover side fixing portion 21. In this state, they are fixed to each other.

  As described above, since L1 is smaller than L2 and L3 is smaller than L4, when the cover side fixing portion 21 and the noise source side fixing portion 1 are fixed to each other, the shape of the cover body 20 is along the raised portion 30. It is held in a stretched and deformed state. At this time, the first end portion 25 and the second end portion 26 of the cover main body 20 are pulled in directions intersecting each other with a portion (support end portion 27) in pressure contact with the top portion 300 of the raised portion 30 as a fulcrum. Specifically, as shown in FIG. 3, the first end portion 25 is pulled in the Y direction in FIG. 3, and the second end portion 26 is pulled in the Z direction in FIG. The support end 27 is pulled in the X direction in FIG. Therefore, a portion of the cover body 20 between the support end 27 and the first end 25 is pulled in a direction between the X direction and the Y direction in FIG. A portion between the portion 27 and the second end portion 26 is pulled in a direction between the X direction and the Z direction in FIG. Therefore, the cover body 20 in the soundproof cover structure of the embodiment is in close contact with the gear housing 3.

  For this reason, in the soundproof cover structure of the embodiment, the cover body 20 is attached to the gear housing 3 having a complicated shape without a gap, and the air propagation sound can be reliably shielded by the cover body 20. Further, the solid propagation sound is reduced by the mass effect of the cover body 20. Furthermore, since the cover main body 20 is made of silicone rubber, which is a high-attenuation material, the solid propagation sound that has propagated to the cover main body 20 is attenuated. For this reason, according to the soundproof cover structure of the embodiment, noise generated in the transmission (noise source device) can be reliably reduced. In addition, the soundproof cover structure of the example is not bulky because it does not have a sound absorbing layer made of a nonwoven fabric or the like.

  In the soundproof cover structure of the present invention, the relationship between L1 and L2 described above is preferably 1.05 ≦ L2 / L1 ≦ 1.3. Further, the distance (W) between the base ends of the two noise source side fixing portions 1 across the top portion 300 of the raised portion 30, and a plane α and a plane α passing through the base ends of the two noise source side fixing portions 1. When the distance (H) from the plane β parallel to and in contact with the top portion 300 is H / W ≧ 5/100, particularly excellent sealing properties and sound insulation properties are exhibited. For reference, in the soundproof cover structure of the example, the linear distance (W shown in FIG. 3) between the base end of the first noise source side fixing portion 11 and the base end of the third noise source side fixing portion 13 is 50 mm. It was. A distance between a plane including the base end of the first noise source side fixing portion 11 and the base end of the third noise source side fixing portion 13 and a plane parallel to the plane and in contact with the top portion 300 (shown in FIG. 3) H) was 16 mm. The linear distance between the base end of the second noise source side fixing portion 12 and the base end of the fourth noise source side fixing portion 14 was also 50 mm. The distance between the plane including the base end of the second noise source side fixing portion 12 and the base end of the fourth noise source side fixing portion 14 and the plane parallel to the plane and contacting the top portion 300 was also 16 mm. It was.

(Comparative example)
The soundproof cover structure of the comparative example has a noise source side fixing portion and a soundproof cover. The noise source side fixing portion of the comparative example is formed integrally with the gear housing similarly to the embodiment, and has the same shape as the noise source side fixing portion 1 of the embodiment. The soundproof cover has a cover body composed of a cover main body and a sound absorbing material laminated on the back side of the cover main body, and four cover side fixing portions integrated with the cover main body. The cover body is made of resin, the sound absorbing material is 10 mm thick, and is made of a non-woven fabric made of PET. The cover body is formed in the same shape as the cover body 20 of the embodiment when attached to the noise source device. The cover side fixing part has the same shape as the cover side fixing part 21 of the embodiment.

(Soundproof evaluation test)
For the soundproof cover structure of the example and the soundproof cover structure of the comparative example, the noise level (dBA) at a frequency of 0 Hz to 1000 Hz at a position 10 mm away from the soundproof cover when noise was generated in the transmission was measured. A graph showing the results of the soundproofing evaluation test is shown in FIG. The solid line in FIG. 4 represents the noise level outside the soundproof cover structure of the example, and the broken line represents the noise level outside the soundproof cover structure of the comparative example.

  According to the graph shown in FIG. 4, the soundproof cover structure of the embodiment greatly reduces the noise of 300 Hz to 600 Hz compared to the soundproof cover structure of the comparative example. In particular, the soundproof cover structure of the embodiment greatly reduces noise around 480 Hz. From this result, it can be seen that the soundproof cover structure of the present invention can reduce the noise generated by the noise device as much as the soundproof cover structure of the comparative example.

It is a principal part expansion disassembled perspective view which represents typically the soundproof cover structure of an Example. It is a principal part expansion perspective view which represents typically the soundproof cover structure of an Example. It is sectional drawing which represents typically a mode that the soundproof cover structure of the Example was cut | disconnected in the AA position in FIG. It is a graph showing the result of a soundproof evaluation test.

Explanation of symbols

1: Noise source side fixing part 2: Soundproof cover 3: Gear housing 20: Cover body 21: Cover side fixing part 30: Raised part

Claims (2)

A noise source cover that covers at least the raised portion of the noise source device having a protruding raised portion, and a plurality of noise source side fixing portions integrated with the noise source device,
The noise source side fixing portion is formed at least one at a position sandwiching the top of the raised portion,
The soundproof cover has a cover body made of an elastic material and has a sheet shape, and a plurality of cover side fixing portions integrated with the cover body,
The soundproof cover is attached to the noise source device with the cover side fixing portion and the noise source side fixing portion being fixed to each other in a state where the cover main body extends and deforms in a shape along the raised portion. A soundproof cover structure characterized by that.   The soundproof cover structure according to claim 1, wherein the elastic material is at least one selected from chloroprene rubber, ethylene propylene rubber, and silicone rubber.

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