JP2005264790A - Sound insulation cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the thermal deterioration of a sound absorbing member by a heat source such as an exhaust manifold. <P>SOLUTION: A sound insulation member 1 comprises a heat insulation part 10 interposed between the sound absorbing member 2 and the heat source 30 in the state of non-contact with the sound absorbing member 2. It is shielded by the heat insulation part 10 that a radiation heat from the heat source 30 is directly radiated to the sound absorbing member 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a soundproof cover that can absorb and suppress sound generated from an engine of an automobile to prevent noise.

  In recent automobiles, a block side cover, an under cover, and the like are disposed around or below the engine in order to shield noise from the engine. These soundproof covers are, for example, a hard sound insulation member made of resin or steel plate, and a sound absorption member made of a polymer foam laminated on the engine side surface of the sound insulation member, as seen in JP-A-10-205352. It is composed of In this soundproof cover, the sound insulation member shields the sound from the engine, and the sound absorption member absorbs the sound from the engine.

  That is, sound waves emitted from the engine as the sound source are absorbed to some extent by the sound absorbing member when passing through the sound absorbing member, and the remaining sound waves reach the shielding member. Since it is difficult for the sound wave to pass through the hard sound insulating member, the sound wave is reflected by the sound insulating member and passes through the sound absorbing member again. Therefore, the sound wave is repeatedly reflected between the engine and the sound insulation member and is absorbed every time it passes through the sound absorption member, so that it is possible to effectively prevent sound.

  By the way, with the recent demand for quietness of vehicles, it is desired to arrange a soundproof cover on the exhaust side of the engine. However, since an exhaust manifold exists on the exhaust side of the engine and the surface thereof is exposed, there is a problem due to heat radiated from the exhaust manifold. That is, the sound absorbing member is generally formed of a urethane foam, and its heat resistance is not high, so there is a risk of deterioration due to heat from the exhaust manifold. When the sound absorbing member is thermally deteriorated, the pore distribution or the apparent density is changed and the sound absorbing characteristics are deteriorated. In addition, since the exhaust manifold exists, there is a situation in which a space for arranging the soundproof cover is narrow and it is not possible to arrange a heat shield.

For this reason, measures are taken on the noise exit side, such as by enlarging the engine undercover, but not on the sound source, but the effect of noise reduction is small compared to attaching the soundproof cover directly to the engine. Further, as seen in Utility Model Registration No. 3028639, it is conceivable to form the sound absorbing member from glass fiber having excellent heat resistance, but there is a problem that the sound absorbing effect is low and it is not practical.
JP-A-10-205352 Utility model registration No. 3028639

  The present invention has been made in view of the above circumstances, and uses a soundproof cover having a sound absorbing member made of a soft porous body, and a problem to be solved for suppressing thermal deterioration of the sound absorbing member due to a heat source such as an exhaust manifold. And

  The soundproof cover of the present invention that solves the above problems comprises a hard, plate-like sound insulation member and a sound absorbing member made of a soft porous material and joined to the sound insulation member, and the sound insulation member is not in contact with the sound absorption member. Therefore, there is a heat shield part interposed between the sound absorbing member and the heat source.

  It is preferable that the heat insulating part extends from the sound insulating member via a heat radiating part having a large surface area. The heat insulating part is preferably joined to the sound insulating member via a heat insulating material, and preferably extends from the sound insulating member via a bridge part having a small cross-sectional area.

  According to the soundproof cover of the present invention, since the radiant heat from the heat source is shielded from being directly radiated to the sound absorbing member by the heat insulating portion, it is possible to suppress the thermal deterioration of the sound absorbing member and to exhibit the sound absorbing function for a long time. can do. Moreover, since the heat insulation part is provided in the sound insulation member, it can be provided even in a narrow space, and the restriction on the shape and the arrangement by the mating member is small. Furthermore, since the heat insulating portion is provided in advance on the sound insulating member, the number of mounting steps does not increase.

  The heat insulating part is configured to extend from the sound insulating member via a heat radiating part having a large surface area, joined to the sound insulating member via a heat insulating material, or via a bridge part having a small cross-sectional area. If the heat insulation part is heated by the radiant heat from the heat source, the temperature rise of the sound insulation member is suppressed, and the thermal deterioration of the sound absorption member can be further suppressed.

  The soundproof cover of the present invention includes a sound insulating member having a heat insulating portion and a sound absorbing member. The soundproof cover of the present invention may be disposed so that the sound absorbing member contacts the sound source, or may be disposed in a state of being separated from the sound source. In order to fix the soundproof cover of the present invention to the sound source, a method of fixing the soundproof cover to the sound source through a rubber mount or the like, or a method of joining the sound absorbing member to the sound source can be used. When fixing to a sound source through a rubber mount or the like, the sound absorbing member may or may not be in contact with the sound source.

  As the sound insulating member, a hard plate-shaped member made of a resin plate, a metal plate, ceramics, or the like can be used. Although it is necessary to have a certain large mass per unit area, the shape is determined by the shape of the sound source and the shape of the arrangement space, and is not particularly limited.

  The sound-absorbing member is made of a soft porous material, and can be made of a polymer foam such as foamed rubber, urethane foam, polyethylene foam, polypropylene foam, or a fiber aggregate such as felt. The material is determined by the temperature of the sound and the frequency of the sound to be absorbed. The thickness can be appropriately determined according to the arrangement space.

  The sound absorbing member and the sound insulating member need to be joined. However, the term “joining” as used herein means that the sound absorbing member and the sound insulating member are separate, and the sound absorbing member is disposed between the sound insulating member and the mating member so as to be in close contact with the sound insulating member when attached. Including cases. If they are not joined, there will be a gap between the sound insulation member and the sound absorption member due to deterioration, etc., and sound may leak from the gap, or sound waves that have entered the gap may vibrate the sound insulation member and generate secondary radiation. . In this sense, it is desirable that the joining is performed on the entire surface of the sound absorbing member.

  In order to join the sound absorbing member to the sound insulating member, the sound absorbing member formed in a predetermined shape can be joined to the sound insulating member by bonding or welding. However, the sound insulating member is disposed in the mold, and the sound absorbing member is disposed in the mold. It is preferable to join by integrally molding the members. In this case, it is desirable to integrally form the sound absorbing member from the urethane foam using a urethane foam resin having excellent adhesiveness.

  In this way, when the sound absorbing member is formed from a urethane foam, it can be formed by urethane foam molding in a mold, so the degree of freedom in shape is great. Therefore, it is possible to easily cope with a case where the soundproof cover has a three-dimensional solid shape or a shape in which the thickness of the sound absorbing member is partially different.

When the sound absorbing member is formed from urethane foam, the apparent density is generally preferably about 0.06 to 0.12 g / cm ³ which is excellent in sound absorbing characteristics. In addition, in the case of integral molding in which the sound insulating member is disposed in the mold to form the sound absorbing member, about 5 mm on one side of the sound insulating member in order to reliably form the urethane foam between the sound insulating member and the mold surface. It is desirable to form a urethane foam with the above thickness.

  The heat-insulating part which characterizes the present invention is interposed between the sound-absorbing member and the heat source in a non-contact manner with the sound-absorbing member. Accordingly, the radiant heat from the heat source is radiated to the sound absorbing member through the heat insulating portion and the air layer existing between the heat insulating portion and the sound absorbing member, and therefore the sound absorbing member is hardly heated and is heated. Deterioration can be suppressed. If the heat insulating part is in contact with the sound absorbing member, the heat of the heat insulating part heated by the radiant heat from the heat source is directly conducted to the sound absorbing member, which is not preferable.

  The heat shield is preferably made of a material having high heat shielding properties and excellent heat resistance, and can be formed of resin, metal, ceramics, or the like. The same material as the sound insulation member may be used.

  It is preferable that the heat insulating part extends from the sound insulating member via a heat radiating part having a large surface area. When heat is radiated to the outside by the heat radiating portion, the amount of heat of the heat insulating portion conducted to the sound insulating member is reduced, and hence thermal deterioration of the sound absorbing member can be suppressed. The heat dissipating part only needs to have a larger surface area per unit area than the surface of a smooth plate. For example, the heat dissipating part may have an uneven surface, a wave shape or a bellows shape. In this case, the heat insulating part and the heat radiating part can be formed from a part of the sound insulating member.

  Moreover, it is also preferable that the heat insulation part is joined to the sound insulation member via a heat insulating material. Even if it does in this way, the calorie | heat amount of the heat insulation part conducted to the sound insulation member decreases, and by extension, the thermal deterioration of a sound absorption member can be suppressed. As the heat insulating material, one having a lower thermal conductivity than the heat shielding portion can be used, but a silicone resin having excellent heat resistance is desirable. In this case, the heat insulating part is a separate member from the sound insulating member.

  Moreover, it is also preferable that the heat insulating part is configured to extend from the sound insulating member via a bridge part having a small cross-sectional area. Even if it does in this way, the calorie | heat amount of the heat insulation part conducted to the sound insulation member decreases, and by extension, the thermal deterioration of a sound absorption member can be suppressed. The smaller the cross-sectional area, the greater the heat conduction resistance, but the bridge portion needs to be able to withstand vibration and the like, and therefore it is preferable to determine the shape in balance with the strength. In this case, the heat insulation part and the bridge part can be formed from a part of the sound insulation member.

  Hereinafter, the present invention will be described specifically by way of examples. The present embodiment relates to a soundproof cover for an engine.

(Example 1)
FIG. 1 shows a state in which the soundproof cover of this embodiment is attached to the engine. The soundproof cover is composed of a sound insulating member 1 having an L-shaped cross section and a sound absorbing member 2 made of urethane foam, and faces the exhaust manifold 30 of the engine 3 with a bolt (not shown) in a state where the sound absorbing member 2 is in contact with the engine 3. It is fixed on the surface to be.

The sound insulating member 1 is formed from an iron plate having a thickness of 0.8 to 1 mm. The sound absorbing member 2 is made of urethane foam having a foam density of 0.1 g / cm ³ and has a thickness of 5 mm. The sound absorbing member 2 is formed by disposing a previously formed sound insulating member 1 in a foaming mold and injecting a foamed urethane resin and integrally forming the same, and integrally forming the sound insulating member 1 at the time of molding. It is joined.

  The sound insulating member 1 further includes a heat insulating portion 10 that extends from the surface of the sound absorbing member 2 and is bent at a substantially right angle toward the sound absorbing member 2 side. The heat shield 10 extends so as to cover the end face 20 without contacting the exposed end face 20 of the sound absorbing member 2, and is interposed between the exhaust manifold 30 serving as a heat source and the exposed end face 20 of the sound absorbing member 2. ing.

  Therefore, according to the soundproof cover of this embodiment, the heat shield 10 extends so as to cover the end face 20 without contacting the exposed end face 20 of the sound absorbing member 2, so that the end face 20 is radiated from the exhaust manifold 3. Direct heating with heat is avoided, and thermal deterioration of the sound absorbing member 2 is suppressed.

(Example 2)
FIG. 2 shows a state in which the soundproof cover of this embodiment is attached to the engine. The soundproof cover is composed of a sound insulating member 4 and a sound absorbing member 2 made of the same urethane foam as in the first embodiment. The sound absorbing member 2 is attached to the exhaust manifold 30 of the engine 3 by a bolt (not shown) in a state where the sound absorbing member 2 is in contact with the engine 3. It is fixed to the opposite surface.

  The sound insulating member 4 includes a base 40 joined to the sound absorbing member 2, a wave-shaped heat radiating part 41 joined to the end surface of the base 40 and extending from the base 40, and the tip of the heat radiating part 41 to the sound absorbing member 2 side. And a heat shield part 42 bent at a substantially right angle. The heat insulating part 42 and the heat radiating part 41 extend so as to cover the end face 20 without contacting the exposed surface of the sound absorbing member 2, and the heat insulating part 42 exposes the exhaust manifold 30 and the sound absorbing member 2 which are heat sources. It is interposed between the end face 20.

  Therefore, according to the soundproof cover of the present embodiment, the heat insulating portion 42 extends so as to cover the end surface 20 without contacting the exposed end surface 20 of the sound absorbing member 2, so that the end surface 20 is radiated from the exhaust manifold 3. Direct heating with heat is avoided. Further, since the heat radiation part 41 has a large surface area, even if the heat shield part 42 is heated by the radiant heat of the exhaust manifold 3, the heat is radiated from the heat radiation part 41. Therefore, thermal deterioration of the sound absorbing member 2 is suppressed.

(Example 3)
FIG. 2 shows a state in which the soundproof cover of this embodiment is attached to the engine. The soundproof cover is composed of a sound insulating member 5 and a sound absorbing member 2 made of the same urethane foam as in the first embodiment. The sound absorbing member 2 is attached to the exhaust manifold 30 of the engine 3 by a bolt (not shown) in a state where the sound absorbing member 2 is in contact with the engine 3. It is fixed to the opposite surface.

  The sound insulating member 5 includes a base 50 joined to the sound absorbing member 2, a heat insulating part 51 having a substantially L-shaped cross section, and a heat insulating part 52 interposed between the base 50 and the heat insulating part 51 to join them together. It is composed of The heat shield 51 extends so as not to contact the exposed surface of the sound absorbing member 2 and covers the surface, and is interposed between the exhaust manifold 30 as a heat source and the exposed surface of the sound absorbing member 2.

  Therefore, according to the soundproof cover of the present embodiment, the heat shield 51 extends so as to cover the surface of the sound absorbing member 2 without contacting the surface, so that the exposed surface is the radiant heat of the exhaust manifold 3. To avoid being heated directly. Further, since the heat insulating portion 52 is formed of silicone resin and has a large heat capacity, even if the heat shield portion 51 is heated by the radiant heat of the exhaust manifold 3, the heat is not easily transmitted to the sound absorbing member 2. Therefore, thermal deterioration of the sound absorbing member 2 is suppressed.

  In this embodiment, a part of the surface of the sound absorbing member 2 is exposed, but the base 50 may cover the surface of the sound absorbing member 2 as shown in FIG.

Example 4
FIG. 5 shows a state in which the soundproof cover of this embodiment is attached to the engine. The soundproof cover is composed of a sound insulating member 6 and a sound absorbing member 2 having a base 21 and a bent portion 22 made of a urethane foam similar to that of the first embodiment, and the base 21 and the bent portion of the sound absorbing member 2 are bent. The portion 22 is fixed by bolts (not shown) in contact with the two surfaces of the engine 3, and the bent portion 22 faces the exhaust manifold 30.

  The sound insulating member 6 includes a base portion 60 joined to the base portion 21 of the sound absorbing member 2 and a heat insulating portion 61 bent from the end portion of the base portion 60 toward the bent portion 22 side at a substantially right angle. The heat insulating portion 61 is bent. It extends so as to cover the exposed surface of the portion 22 in a non-contact manner, and is interposed between the exhaust manifold 30 serving as a heat source and the bent portion 22.

  Therefore, according to the soundproof cover of the present embodiment, the heat shield 61 extends so as to cover the surface of the bent portion 22 that is not in contact with the exposed portion. To avoid being heated directly. Therefore, thermal deterioration of the sound absorbing member 2 is suppressed.

  In this embodiment, the base 21 and the bent portion 22 of the sound absorbing member 2 are integrated, but the base 21 and the bent portion 22 may be separate members as shown in FIG.

(Example 5)
FIG. 7 shows a state in which the soundproof cover of this embodiment is attached to the engine. The soundproof cover is composed of a sound insulating member 6 and a sound absorbing member 2 made of the same urethane foam as in the first embodiment and having a substantially L-shaped cross section. The surface of the corner portion 23 of the sound absorbing member 2 has a step shape and is exhausted. Opposite the manifold 30.

  The sound insulating member 6 has an L-shaped cross section, and both end portions of the sound absorbing member 2 are joined. Between the surface of the corner portion 23 and the sound insulating member 6, a gap 7 communicating with outside air is interposed at both ends. Therefore, according to the soundproof cover of this embodiment, the portion of the sound insulating member 6 that faces the gap 7 functions as the heat insulating portion 61, and the heat insulating portion 61 is not in contact with the exposed surface of the corner portion 23, and the surface is Since it extends so as to cover, it is avoided that the corner portion 23 is directly heated by the radiant heat of the exhaust manifold 3. Therefore, thermal deterioration of the sound absorbing member 2 is suppressed.

(Example 6)
FIG. 8 shows the main part of the soundproof cover of this embodiment. This soundproof cover is the same as the soundproof cover of Example 4 except that the base portion 60 of the sound insulation member 6 has a bridge portion 62.

  The bridge 62 is provided at the boundary between the base 60 and the heat shield 61 and has a smaller cross-sectional area than the base 60 and the heat shield 61. Therefore, even if the heat shield 61 is heated by the exhaust manifold 30, the amount of heat transmitted to the base 60 is small, so that thermal deterioration of the sound absorbing member 2 can be further suppressed.

  The soundproof cover of the present invention can be used not only in the exhaust manifold of an automobile but also in the vicinity of a heat source such as an exhaust pipe or a heat source such as a boiler or a dryer.

It is sectional drawing shown in the state which attached the soundproof cover of one Example of this invention to the engine. It is sectional drawing shown in the state which attached the soundproof cover of the 2nd Example of this invention to the engine. It is sectional drawing shown in the state which attached the soundproof cover of the 3rd Example of this invention to the engine. It is sectional drawing equivalent to FIG. 3 which shows the other aspect of the soundproof cover of the 3rd Example of this invention. It is sectional drawing shown in the state which attached the soundproof cover of the 4th Example of this invention to the engine. It is sectional drawing equivalent to FIG. 5 which shows the other aspect of the soundproof cover of the 4th Example of this invention. It is sectional drawing shown in the state which attached the soundproof cover of the 5th Example of this invention to the engine. It is a principal part perspective view of the soundproof cover of the 6th Example of this invention.

Explanation of symbols

1: Sound insulation member 2: Sound absorption member 3: Engine
10: Heat shield 30: Exhaust manifold (heat source)

Claims (4)

  The sound insulating member is composed of a hard and plate-like sound insulating member and a sound absorbing member made of a soft porous body and joined to the sound insulating member, and the sound insulating member is not in contact with the sound absorbing member and interposed between the sound absorbing member and the heat source. A soundproof cover characterized by having a heat insulating part.   The sound insulation cover according to claim 1, wherein the heat insulation part extends from the sound insulation member via a heat radiation part having a large surface area.   The sound insulation cover according to claim 1, wherein the heat insulation part is joined to the sound insulation member via a heat insulating material.   The sound insulation cover according to claim 1, wherein the heat insulation portion extends from the sound insulation member via a bridge portion having a small cross-sectional area.

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