JP2015107667A - Hood resonator device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hood resonator device for a vehicle which can suppress the intrusion of noise generated from a sound generation source such as an engine room into a cabin.SOLUTION: A hood resonator device 100 has resonance spaces 61, 62 and 63 which are formed between an outer panel 50 and an inner panel 51 of an engine hood 20. Holes 70 communicating with the resonance spaces 61, 62 and 63 are formed at the inner panel 51. By this constitution, a plurality of resonators 71, 72 and 73 are constituted. The resonance spaces 61, 62 and 63 are air-tightly partitioned by a partitioning member 66. The resonators 71, 72 and 73 are covered with a sound insulation material 80. By making opening rates of the holes 70 differ from one another at the respective resonance spaces 61, 62 and 63 according to a frequency of a sound which should be suppressed, resonance frequencies of the resonance spaces 61, 62 and 63 are made to differ from one another.

Description

  The present invention relates to a vehicle hood resonator device using a hood member such as an engine hood.

  A part of the sound emitted from the sound source in the engine room of the vehicle (for example, a power plant including an engine and a transmission arranged in the engine room) enters the vehicle interior through the vehicle body. Alternatively, the sound emitted from the sound source may once get out of the vehicle and then enter the vehicle again. There are various sounds that enter the car, and even if the sound volume is the same, some sounds feel uncomfortable depending on the sound quality and frequency, and some sounds don't bother you. For this reason, it is not necessary to suppress all of the vehicle interior sound, and it is sufficient to suppress the noise (noise) that is particularly disturbing.

  For example, in Patent Document 1, one resonance space is formed between an outer panel (hood outer) and an inner panel (hood inner) constituting an engine hood (bonnet), and a hole communicating with the resonance space is formed in the inner panel. A muffler using an engine hood as a resonator is disclosed.

  Alternatively, as seen in Patent Document 2, a dash panel of a vehicle is configured by an inner panel and an outer panel, and a single space is formed between the inner panel and the outer panel, and a plurality of cylindrical protrusions are formed on the outer panel. A sound-absorbing dash panel having a sound-absorbing function by Helmholtz resonance has also been proposed by providing a hole in each protrusion.

JP-A-11-240466 Japanese Patent Laid-Open No. 10-236333

  In the silencer of Patent Document 1, the resonance frequency is uniquely determined by the resonance space formed in the engine hood, the size of the hole, and the like, so that only sounds in a specific frequency range can be suppressed. In the engine room, sound of various sound quality and frequency is generated from the engine, transmission, belts that rotate pulleys, intake and exhaust manifolds, etc. Even if the sound of one specific frequency range is suppressed, It does not mean that the noise in the car has been eliminated.

  In the sound absorbing dash panel of Patent Document 2, the resonance frequency is uniquely determined by the size of the space formed between the outer panel and the inner panel and the aperture ratio of the hole of the protrusion. Only sound can be suppressed. Moreover, since the dash panel is intentionally formed by two members, the outer panel and the inner panel, not only the structure is complicated, but also the weight of the dash panel and the space for installation are increased.

  Accordingly, an object of the present invention is to provide a vehicle hood resonator device that can reduce noise in a vehicle by suppressing sounds in a plurality of frequency regions to be suppressed among sounds in various frequency regions generated from an engine room or the like. Is to provide.

  A vehicle hood resonator device according to the present invention includes a plurality of independent resonance spaces formed between an outer panel and an inner panel of a hood member, and the outer panel and the inner panel for hermetically partitioning the plurality of resonance spaces from each other. Are formed in the inner panel for each of the plurality of resonance spaces, and each of the resonance spaces communicates with each other and has a different aperture ratio with respect to each resonance space. A plurality of resonators having different frequencies, and a sound absorbing and insulating material attached to the inner surface side of the hood member in a state of covering each of the resonators. An example of the hood member is an engine hood that covers an engine room of a vehicle.

  In one embodiment, the sizes of the holes formed in the resonance spaces are the same and the sizes of the resonance spaces are different from each other. In another embodiment, the size of the holes formed in each resonance space is common to each other, and the number of the holes is different for each resonance space. Moreover, the sizes of the holes formed in the resonance spaces may be different from each other.

  According to the vehicle hood resonator device of the present invention, a hood member such as an engine hood composed of an outer panel and an inner panel can be used, and a plurality of noises that cause noise among various sounds generated from an engine room or the like. Can be suppressed by a plurality of resonators having resonance frequencies different from each other, and thus the in-vehicle noise can be reduced.

1 is a perspective view of a vehicle provided with a hood resonator device according to one embodiment of the present invention. The perspective view of the state which opened the engine hood of the vehicle shown by FIG. The top view which looked at the engine hood of the vehicle shown by FIG. 1 from upper direction. Sectional drawing which follows the F4-F4 line | wire in FIG. The top view which represented typically the hood resonator apparatus of the vehicle shown by FIG. The figure which shows the relationship between the vehicle interior sound and a frequency regarding the presence or absence of a hood resonator apparatus and a sound-absorbing / insulating material.

Hereinafter, a vehicle including a hood resonator device according to one embodiment of the present invention will be described with reference to FIGS. 1 to 6.
FIG. 1 is a perspective view of the vehicle 10. 1, the direction indicated by the arrow X1 indicates the front of the vehicle body 11, the arrow X2 indicates the rear of the vehicle body 11, and the arrow Y indicates the width direction of the vehicle body 11 (also referred to as the vehicle width direction). A cabin (cabinet) 12 formed in the vehicle body 11 is surrounded by a windshield glass 13 and a roof 14. An engine hood 20, which is an example of a hood member, is provided in front of the cabin 12 and on the front side of the windshield glass 13. The engine hood 20 forms a part of the vehicle body 11.

  FIG. 1 shows a state where the engine hood 20 is closed. FIG. 2 shows a state where the engine hood 20 is opened. An engine room 21 is formed below the engine hood 20. The engine room 21 accommodates a power plant 25 including an engine and a transmission. The power plant 25 becomes a sound source when the engine rotates. The engine room 21 is closed by the engine hood 20.

  As shown in FIG. 2, the engine room 21 is configured by a vehicle body skeleton member 30 or the like that forms a front structure of the vehicle body 11. An example of the vehicle body skeleton member 30 has high rigidity such as a side member extending in the front-rear direction of the vehicle body 11, an upper frame 31, a wheel house inner, a front end upper bar 32 extending in the vehicle width direction, a cowl top member 33, a dash panel 34, and the like. It is a member.

  The rear end 20a of the engine hood 20 is attached to a part of the vehicle body skeleton member 30 (for example, the upper frame 31) by a pair of hood hinges 40. The engine hood 20 can be rotated (opened / closed) in the vertical direction around the hood hinge 40. As shown in FIG. 1, the front end 20 b of the engine hood 20 is fixed by a hood lock mechanism 41 in a state where the engine hood 20 is closed.

  An example of the hood lock mechanism 41 includes a striker 42 (shown in FIG. 2) and a latch unit 43, and the engagement between the striker 42 and the latch unit 43 is performed by operating an operation unit disposed in the cabin 12. Can be released (unlocked). An elastic member 45 is disposed on the upper surface of the vehicle body skeleton member 30. The elastic member 45 urges the closed engine hood 20 upward.

  FIG. 3 is a plan view of the engine hood 20 as viewed from above. FIG. 4 shows a partial cross section of the engine hood 20 along the line F4-F4 in FIG. The engine hood 20 is composed of an outer panel 50 and an inner panel 51. The outer panel 50 is disposed on the outer side (upper side) of the vehicle body 11. The inner panel 51 is disposed below the outer panel 50 (side facing the engine room 21). The outer panel 50 is made of a steel plate having a thickness of 0.7 to 0.8 mm, for example. The inner panel 51 is made of a steel plate having a thickness of 0.6 to 1.0 mm, for example.

  The outer panel 50 and the inner panel 51 are formed into a predetermined shape by pressing a metal plate such as a steel plate or an aluminum alloy. On the inner panel 51, a plurality of convex portions 51a (shown in FIG. 4) projecting toward the engine room 21 are formed by pressing. The rigidity of the inner panel 51 is enhanced by the convex portion 51a. Therefore, the rigidity of the engine hood 20 can be increased by superimposing the inner panel 51 on the outer panel 50 and joining them together. Note that a part of the engine hood 20 may be formed of a resin component.

  A plurality of (for example, three) resonance spaces 61, 62, and 63 that are independent from each other are formed between the convex portion 51a of the inner panel 51 and the outer panel 50. As shown in FIG. 4, the outer panel 50 and the inner panel 51 are fixed to each other by an adhesive (seal material) 65 at a portion of the inner panel 51 excluding the convex portion 51 a.

  The adhesive material 65 also functions as a partition member for making the resonance spaces 61, 62, and 63 aerodynamically independent from each other. The resonance spaces 61, 62, and 63 are different in size from each other and are airtightly partitioned from each other by a partition member 66 (shown in FIG. 3). As the partition member 66, a resin-based sealing agent common to the adhesive 65 may be used. The peripheral portion 50a of the outer panel 50 is airtightly joined to the peripheral edge of the inner panel 51 by a bending edge such as hemming bending.

  FIG. 5 schematically shows the first to third resonance spaces 61, 62, 63. These resonance spaces 61, 62, and 63 can change the area ratio of each other according to the position where the partition member 66 (shown in FIG. 3) is provided. The inner panel 51 is formed with holes 70 communicating with the respective resonance spaces 61, 62, 63.

  The first resonator 71 corresponding to the first resonance frequency is constituted by the first resonance space 61 and one or more holes 70 communicating with the resonance space 61. The second resonance space 62 and one or more holes 70 communicating with the resonance space 62 constitute a second resonator 72 corresponding to the second resonance frequency. The third resonator 73 corresponding to the third resonance frequency is configured by the third resonance space 63 and one or more holes 70 communicating with the resonance space 63.

  These resonators 71, 72, 73 have a function of absorbing sounds of the first, second, and third resonance frequencies, respectively, based on the sound absorption principle of a Helmholtz resonator that causes frictional loss of air by echo resonance. Yes. In the Helmholtz resonator, a sound absorption force (sound absorption principle) is exhibited at a resonance frequency (resonance frequency). For example, when sound generated in the engine room 21 enters the resonance spaces 61, 62, 63 through the hole 70, the air in the resonance spaces 61, 62, 63 acts as a “spring”, and is near the hole 70 at the resonance frequency. When air vibrates violently, a sound absorbing action is generated due to friction loss caused by the “spring” and the mass of air.

  As shown in FIGS. 2 and 4, a sound absorbing and insulating material 80 is attached to the lower surface of the inner panel 51. The sound absorbing and insulating material 80 referred to in this specification is a member having a function of blocking sound and a function of absorbing sound. The sound-absorbing and insulating material 80 can block sound and absorb sound by converting the vibration energy of sound into, for example, thermal energy due to friction between fibers. The sound absorbing and insulating material 80 generally has higher sound absorption and blocking effects as the frequency becomes higher.

  An example of the sound absorbing and insulating material 80 is made of an aggregate of heat resistant fibers that can withstand the heat generated from the power plant 25 in the engine room 21. For example, as a heat-resistant sound-absorbing and insulating material for high temperature of 100 ° C. or higher, a felt-like fiber aggregate made of polyethylene terephthalate (PET) is exemplified. When the temperature of the engine room 21 is relatively low, for example, a polypropylene-based felt-like fiber aggregate can be employed. Further, it may be a felt-like glass wool that is compression-molded, or a sound absorbing and insulating material in which a resin foam is laminated on a metal foil.

  The resonators 71, 72, 73 and the sound absorbing and insulating material 80 constitute a hood resonator device 100. In the hood resonator device 100 of the present embodiment, the aperture ratios of the holes 70 communicating with the resonance spaces 61, 62, and 63 are made different from each other so that the frequencies of a plurality of types of sound ranges to be suppressed can be handled. .

  By doing so, the hood resonator device 100 formed in one engine hood 20 can cope with a plurality of resonance frequencies. The aperture ratio is the ratio of the area of the hole 70 to the area of each resonance space 61, 62, 63 in the plan view of each resonance space 61, 62, 63 as shown in FIG. The sizes (inner diameters) of the holes 70 communicating with the resonance spaces 61, 62, and 63 are preferably common to each other. However, if a desired aperture ratio can be obtained, the sizes of the holes 70 are different from each other. Also good. The larger the hole 70, the larger the aperture ratio. Further, as the number of holes 70 increases, the aperture ratio increases.

  As described above, in the hood resonator device 100 according to this embodiment, the aperture ratios of the holes 70 communicating with the resonance spaces 61, 62, and 63 are different from each other. That is, the area of the resonance spaces 61, 62, and 63 is considered so that the resonance frequency obtained according to the aperture ratio of the hole 70 communicating with each of the resonance spaces 61, 62, and 63 corresponds to the frequency of the sound to be suppressed. Above, the number of holes 70, the size of the holes 70, and the position of the partition member 66 are set.

The aperture ratio of the hole 70 can be obtained based on the following formula (1). In Expression (1), P is the aperture ratio, c is the speed of sound, _fr is the frequency of the sound to be suppressed, L is the depth of the resonance space, and t is the thickness of the member (inner panel) having a hole. An example of the plate thickness t was calculated as 1.0 mm, an example of the depth L was 20 mm, and the sound velocity c = 343 m / s.

As an example, the aperture ratio (P) when the frequency (f _r ) of the sound to be suppressed is 2000 Hz is 2.68%. The aperture ratio (P) when the frequency (f _r ) of the sound to be suppressed is 3000 Hz is 6.038%. For this reason, when it is desired to suppress 2000 Hz sound by the first resonator 71, one or more in the first resonance space 61 so that the aperture ratio with respect to the entire area of the first resonance space 61 is 2.68%. The hole 70 is formed. When it is desired to suppress the 3000 Hz sound by the second resonator 72, one or more holes are formed in the second resonance space 62 so that the aperture ratio with respect to the entire area of the second resonance space 62 is 6.038%. 70 is formed.

  If the size of the hole 70 formed in each resonance space 61, 62, 63 is common, the aperture ratio increases as the number of holes 70 increases. That is, when the size of the hole 70 is common, the aperture ratio can be adjusted by changing the number of the holes 70 for each of the resonance spaces 61, 62, 63. When the size of the hole 70 is common, the aperture ratio can be adjusted by changing the area ratio of the resonance spaces 61, 62, 63 by changing the position of the partition member 66.

  As described above, the resonance spaces 61, 62, and 63 are set so that the aperture ratio of the holes 70 for the resonance spaces 61, 62, and 63 is a value that can obtain the resonance frequency corresponding to the sound to be suppressed. In consideration of the respective areas, measures such as setting the number and size of the holes 70, changing the size of the convex portion 51a of the inner panel 51, or adjusting the position of the partition member 66, The aperture ratio for each of the resonance spaces 61, 62, 63 is adjusted.

  The sound absorbing and insulating material 80 can efficiently absorb sound and block sound in a high frequency range. On the other hand, the resonators 71, 72, and 73 can exhibit a sound absorbing action in a relatively low frequency range of several hundred Hz to several thousand Hz. Therefore, by the synergistic effect of the resonators 71, 72, 73 and the sound absorbing and insulating material 80, the noise level of an annoying sound that is particularly desired to be suppressed among the sounds generated from the engine room 21 is reduced by the hood resonator device 100. be able to.

  A two-dot chain line L1 in FIG. 6 schematically illustrates the relationship between the frequency of the vehicle that does not include the hood resonator device and the sound absorbing and insulating material and the sound in the vehicle. A broken line L2 in FIG. 6 shows the relationship between the frequency of the vehicle having the hood resonator device but not having the sound absorbing and insulating material and the sound in the vehicle. A solid line L3 in FIG. 6 indicates the relationship between the frequency of the vehicle and the sound in the vehicle according to this embodiment including both the hood resonator device and the sound absorbing and insulating material.

  Since the hood resonator device 100 of the present embodiment includes the resonators 71, 72, 73 corresponding to a plurality of resonance frequencies, for example, due to the sound absorbing action of the first resonator 71 and the second resonator 72, FIG. As shown by A and B, at least two kinds of frequency band sounds can be reduced.

  In carrying out the present invention, the number of resonators provided on the hood member may be two or three or more. In short, a plurality of resonators having different resonance frequencies may be formed. Further, the hood member may be other than the engine hood, and in short, any hood member that covers the sound generation source may be used. In addition, the outer panel and inner panel that make up the hood member, the number and shape of the resonant space, the shape and size of the opening, the partition member and the sound absorbing and insulating material, the shape, number, and material of each element that makes up the hood resonator device Needless to say, the present invention can be implemented by variously changing specific aspects such as design and arrangement.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Vehicle body, 20 ... Engine hood (hood member), 21 ... Engine room, 25 ... Power plant, 50 ... Outer panel, 51 ... Inner panel, 51a ... Convex part, 61, 62, 63 ... Resonance space, 65 ... Adhesive material (partition member), 66 ... Partition member, 70 ... Hole, 71, 72, 73 ... Resonator, 80 ... Sound absorbing / insulating material, 100 ... Food resonator device.

Claims (5)

A plurality of independent resonance spaces formed between the outer panel and the inner panel of the hood member;
A partition member disposed between the outer panel and the inner panel in order to hermetically partition the plurality of resonance spaces from each other;
A plurality of resonators formed in the inner panel for each of the plurality of resonance spaces, each of which is in communication with each resonance space and having a different opening ratio with respect to each resonance space, thereby making the resonance frequencies of each resonance space different from each other;
A sound absorbing and insulating material attached to the inner surface side of the hood member in a state of covering each of the resonators;
A vehicle hood resonator device characterized by comprising:   The vehicle hood resonator device according to claim 1, wherein the hood member is an engine hood that covers an engine room of the vehicle.   3. The vehicle hood resonator device according to claim 1, wherein the sizes of the holes formed in the resonance spaces are common to each other and the sizes of the resonance spaces are different from each other.   The size of the holes formed in each resonance space is common to each other, and the number of the holes is different from each other for each resonance space. The vehicle hood resonator device as described.   3. The vehicle hood resonator device according to claim 1, wherein the holes formed in the resonance spaces have different sizes. 4.

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