JP2021160677A - Vehicle external noise reduction device - Google Patents

Abstract

To provide a vehicle external noise reduction device capable of reducing noise that is propagated (radiated) to the lateral sides of a vehicle through an underfloor of the vehicle.SOLUTION: A vehicle external noise reduction device 1R includes a groove-shaped part having a belt-shaped bottom wall part extending in a vehicle longitudinal direction and a pair of side wall parts respectively extending in the vehicle longitudinal direction along opposite ends in the width direction of the bottom wall part and extending upward from the opposite ends in the width direction of the bottom wall part. One side wall part of the pair of side wall parts that is located on an inner side in a vehicle width direction includes a sound absorbing portion made of sound absorbing material, and the other side wall part is positioned on the inner side in the vehicle width direction relative to a butting part of an inner locker panel and an outer locker panel.SELECTED DRAWING: Figure 6

Description

The present invention relates to an external noise reduction device.

Generally, when the vehicle is running, noise is generated from the vehicle, and the noise (hereinafter referred to as "outside noise") is propagated around the vehicle. For example, Patent Document 1 below discloses a cover attached below a drive device such as an engine or a transmission. At least part of this cover is made of sound absorbing material. The portion made of this sound absorbing material absorbs the noise radiated from the engine, transmission, etc., and reduces the noise outside the vehicle.

Jitsuzensho 55-0377727

(Problems to be solved by the invention)
When the vehicle is running, not only noise is radiated from drive devices such as an engine and a transmission, but also noise caused by friction between the tire and the road surface (hereinafter referred to as tire noise) is also radiated. The tire noise on one side in the vehicle width direction of the vehicle passes through the underfloor surface of the vehicle body, propagates to the other end side in the vehicle width direction, and propagates to the side of the vehicle.

The present invention has been made to address the above problems, and an object of the present invention is to provide an external noise reduction device capable of reducing noise propagated (radiated) to the side of a vehicle through under the floor of the vehicle. be.

(Means to solve problems)
In order to achieve the above object, the vehicle exterior noise reduction device according to the present invention is a locker provided on the side of the vehicle to reinforce the lower side of the entrance / exit, and is extended in the front-rear direction of the vehicle. Applicable to vehicles equipped with a rocker in which an outer rocker panel having an inwardly open groove shape in the vehicle width direction and an inner rocker panel having an outwardly open groove shape in the vehicle width direction are abutted and joined to each other. Will be done.
The vehicle exterior noise reduction device extends in the vehicle front-rear direction along both ends of the strip-shaped bottom wall portion extending in the vehicle front-rear direction and both ends in the width direction of the bottom wall portion, and extends in the vehicle front-rear direction. A groove-shaped portion having a pair of side wall portions extending upward from both ends thereof, and one side wall portion of the pair of side wall portions, which is located inside in the vehicle width direction, is provided. , A sound absorbing portion made of a sound absorbing material, and the other side wall portion of the pair of side wall portions is arranged inside in the vehicle width direction with respect to the abutting portion between the inner rocker panel and the outer rocker panel. NS.

The vehicle exterior noise reduction device according to one aspect of the present invention has a plurality of groove-shaped portions arranged in parallel at predetermined intervals in the vehicle width direction.

Further, in the vehicle exterior noise reduction device according to another aspect of the present invention, the bottom wall portion and the pair of side wall portions are integrally formed by using the sound absorbing material.

Further, in the vehicle exterior noise reduction device according to another aspect of the present invention, at the end portion of the floor undercover of the vehicle body in the vehicle width direction, which is arranged in a predetermined area including the central portion in the vehicle width direction. It is joined or integrally molded.

While the vehicle to which the external noise reduction device according to the present invention is applied, for example, noise generated at the left end of the vehicle (between the left wheel and the ground) is generated between the ground and the underfloor surface of the vehicle body. In the process of propagating to the right through the space, the sound wave of the noise is attenuated (absorbed) by the side wall on the left side of the noise reduction device outside the vehicle. On the underfloor surface of the vehicle body, the noise spectrum (frequency characteristics) is rarely uniform, and the sound pressure at a specific frequency often increases locally. Therefore, by arranging the side wall portion of the groove-shaped portion of the vehicle exterior noise reduction device according to the present invention in a portion where the sound pressure is high, the vehicle exterior noise can be effectively reduced.

It is a perspective view of the vehicle to which the vehicle exterior noise reduction device according to one embodiment of the present invention is applied, viewed from diagonally right front. It is a perspective view of the vehicle to which the vehicle exterior noise reduction device according to one embodiment of the present invention is applied, viewed from diagonally left front. It is a perspective view of a locker. It is a cross-sectional view of the lower part of the floor of the vehicle body (cross-sectional view perpendicular to the front-rear direction of the vehicle). It is a perspective view of the vehicle exterior noise reduction device which concerns on 1st Embodiment. FIG. 6 is a cross-sectional view perpendicular to the longitudinal direction of the vehicle exterior noise reduction device of FIG. It is sectional drawing which shows the arrangement position of the vehicle exterior noise reduction device of FIG. It is a graph of the amount of noise reduction outside the vehicle of 1st Embodiment. It is a perspective view of the vehicle exterior noise reduction device according to the second embodiment, and has three groove-shaped portions. It is sectional drawing which shows the arrangement position of the outside noise reduction device of FIG. FIG. 5 is a perspective view of the vehicle exterior noise reduction device according to the second embodiment, which is a vehicle exterior noise reduction device having five groove-shaped portions. It is sectional drawing which shows the arrangement position of the outside noise reduction device of FIG. It is a graph of the amount of noise reduction outside the vehicle of the 2nd embodiment. It is sectional drawing which is perpendicular to the longitudinal direction of the vehicle exterior noise reduction device which concerns on a modification. It is sectional drawing which shows the structure of the preliminary verification. It is a graph of the preliminary verification result of FIG.

(First Embodiment)
Hereinafter, the vehicle exterior noise reduction device 1 according to the first embodiment of the present invention will be described. Here, the configuration of the vehicle V to which the external noise reduction device 1 is applied will be briefly described. As shown in FIGS. 1A and 1B, the vehicle V includes a vehicle body VB and four wheel (tire) VHs rotatably supported by the vehicle body VB. Openings OL and OR as entrances and exits are provided on both side surfaces of the vehicle body VB.

The vehicle body VB includes a pair of left and right rockers RL and RR extending in the front-rear direction of the vehicle along the lower sides of the openings OL and OR, respectively. The rockers RL and RR are members that reinforce both side portions of the floor surface of the vehicle interior VC of the vehicle body VB in the vehicle width direction. The rocker RL on the left side and the rocker RR on the right side have a symmetrical shape. Therefore, the configuration of the rocker RR will be described below, and the description of the rocker RL will be omitted.

As shown in FIG. 2, the rocker RR is a cylindrical member extending in the front-rear direction of the vehicle. The rocker RR includes an inner rocker panel P1 and an outer rocker panel P2. The inner rocker panel P1 constituting the left half of the rocker RR is a groove-shaped member opened to the right, and the outer rocker panel P2 forming the right half of the rocker RR is a groove-shaped member opened to the left. It is a member.

That is, the inner rocker panel P1 includes a strip-shaped vertical wall portion P1a extending in the front-rear direction of the vehicle and a pair of upper and lower horizontal wall portions P1b and P1c, respectively. The vertical wall portion P1a is arranged so that the wall thickness direction is parallel to the vehicle width direction. The horizontal wall portions P1b and P1c extend from the upper end and the lower end of the vertical wall portion P1a to the right, respectively. Further, the inner rocker panel P1 extends in the vehicle front-rear direction along the right end of the side wall portion P1b, and extends in the vehicle front-rear direction along the flange portion P1d extending upward from the right end of the side wall portion P1b and the right end of the side wall portion P1c. In addition, a flange portion P1e extending downward from the right end of the lateral wall portion P1c is provided.

The inner rocker panel P1 and the outer rocker panel P2 have the same groove shape. That is, the outer rocker panel P2 includes a vertical wall portion P2a, a horizontal wall portion P2b, a horizontal wall portion P2c, a flange portion P2d, and a flange portion P2e similar to the inner rocker panel P1.

The flange portion P1d and the flange portion P2d are joined in a butt state, and the flange portion P1e and the flange portion P2e are joined in a butt state.

Further, as shown in FIG. 3, the vehicle body VB includes a floor undercover UC extending in the front-rear direction of the vehicle between the rocker RL on the left side and the rocker RR on the right side. The floor undercover UC includes a bottom wall portion UCa and side wall portions UCb, UCb. The bottom wall portion UCa is a substantially rectangular plate-shaped portion extending in the front-rear direction of the vehicle. The bottom wall portion UCa is arranged so that the wall thickness direction coincides with the vehicle height direction. The side wall portions UCb and UCb extend upward from both ends of the bottom wall portion UCa in the vehicle width direction, and extend in the vehicle front-rear direction along both ends of the bottom wall portion UCa in the vehicle width direction. There is. The floor undercover UC is arranged at the center of the underfloor surface of the passenger compartment VC in the vehicle width direction.

The vehicle exterior noise reduction device 1 is composed of a pair of left and right vehicle exterior noise reduction devices 1L and 1R. The vehicle exterior noise reduction devices 1L and 1R are arranged at predetermined positions in the area extending from the side wall portions UCb and UCb to the lower space between the rockers RL and RR, respectively (arrangement example (A) to FIG. 6). See example (E)). The vehicle exterior noise reduction device 1L on the left side and the vehicle exterior noise reduction device 1R on the right side have symmetrical shapes. Hereinafter, the structure of the vehicle exterior noise reduction device 1R will be described, and the description of the vehicle exterior noise reduction device 1L will be omitted. The outside noise reduction devices 1L and 1R are fixed to the skeleton member of the vehicle body VB by using a fastening member, an adhesive tape, or the like (not shown).

As shown in FIG. 4, the vehicle exterior noise reduction device 1R is extended in the vehicle front-rear direction. The cross section S perpendicular to the longitudinal direction (vehicle front-rear direction) of the vehicle exterior noise reduction device 1R has a shape as shown in FIG. The shape of the cross section S is constant from the front end portion to the rear end portion in the longitudinal direction (vehicle front-rear direction) of the vehicle exterior noise reduction device 1R. That is, the vehicle exterior noise reduction device 1R includes a strip-shaped lower wall portion 11, side wall portions 12a and 12b, and an upper wall portion 13 extending in the front-rear direction of the vehicle, respectively. The lower wall portion 11 is arranged so that the wall thickness direction is parallel to the vehicle height direction. The side wall portion 12a extends obliquely to the left and upward from the left end of the lower wall portion 11, and extends in the vehicle front-rear direction along the left end of the lower wall portion 11. The side wall portion 12b extends upward from the right end of the lower wall portion 11 and extends in the front-rear direction of the vehicle along the right end of the lower wall portion 11. That is, the vehicle exterior noise reduction device 1R is a groove-shaped portion G composed of a lower wall portion 11 and side wall portions 12a and 12b, and includes a groove-shaped portion G extending in the front-rear direction of the vehicle and open upward. The height of the upper end of the side wall portion 12a and the height of the upper end of the side wall portion 12b are substantially the same. In the present embodiment, the groove depth D _G of the interposition portion G is substantially the same as the vertical dimension of the side wall portion UCb of the floor under cover UC (vehicle height direction), the groove depth D _G, It may be set smaller than the vertical dimension (vehicle height direction) of the side wall portion UCb, or may be set larger.

The upper wall portion 13 extends from the upper end portion of the side wall portion 12a to the left and extends in the front-rear direction of the vehicle.

The vehicle exterior noise reduction device 1R having the above configuration is, for example, an integrally molded product in which animal hair, chemical fibers, etc. are compression molded. Incidentally, the groove width W1 _G of the lower of the interposition portion G is, for example, 65 mm. Groove width W2 _G of the top of the interposition portion G is, for example, 70 mm. Groove depth _{D G} of the interposition portion G is, for example, 42mm. _{The width W 13 of the} upper wall portion 13 is, for example, 33 mm. The wall thickness of each wall portion is common, for example, 7 mm.

While the vehicle V to which the vehicle outside noise reduction device 1R is applied, the noise generated at the left end of the vehicle V (between the left wheel VH and the ground) is generated between the ground and the underfloor surface of the vehicle body VB. In the process of propagating to the right through the space, the sound wave of the noise is guided to the space between the right end of the floor undercover UC and the side wall portion 12a of the vehicle exterior noise reduction device 1R, and the sound wave is guided to the space. , Mainly, it is attenuated (absorbed) by the side wall portion 12a.

Here, the relationship between the arrangement position of the vehicle exterior noise reduction device 1R on the underfloor surface of the vehicle body VB and the vehicle exterior noise reduction amount was analyzed (computer simulation). In the analysis, various conditions were set as follows.
-Sound waves (for example, pink noise) are emitted from a point sound source below the central portion of the vehicle body VB in the vehicle width direction.
-The distance between the observation point and the central portion of the vehicle body VB in the vehicle width direction in the left-right direction is 7.5 m.
-The height of the observation point (distance from the ground) is 1.2 m.

Further, the origin is directly below the abutting portion between the flange portion P1e and the flange portion P2e of the rocker RR, and the distance d from the origin to the side wall portion 12b (the upper end of the side wall portion 12b) is set as follows (see FIG. 6). ). Here, as shown in FIG. 14, a state in which the abutting portion between the flange portion P1e and the flange portion P2e exists inside the groove portion G (FIG. 14 (H)), and the flange portion P1e and the flange inside the groove portion G. Preliminary verification was carried out to compare the amount of noise reduction outside the vehicle in the state where the butted portion of the portion P2e does not exist (FIG. 14 (I)). As a result, as shown in FIG. 15, better results were obtained in the latter (FIG. 14 (I)) than in the former (FIG. 14 (H)). In particular, it was found that the latter has a larger amount of reduction in noise outside the vehicle in the high frequency range. Therefore, in any of the following arrangement examples, the side wall portion 12b is located to the left of the abutting portion between the flange portion P1e and the flange portion P2e of the rocker RR (inside (center portion side) in the vehicle width direction of the vehicle body VB). I set it to.
・ Arrangement example (A) ・ ・ ・ d = 0 mm
・ Arrangement example (B) ・ ・ ・ d = 45 mm
・ Arrangement example (C) ・ ・ ・ d = 155 mm
・ Arrangement example (D) ・ ・ ・ d = 265 mm
・ Arrangement example (E) ・ ・ ・ d = 375 mm

Under the above conditions, the amount of outside noise reduction at the observation point (sound pressure of noise at the observation point when there is no outside noise reduction device / sound pressure of noise at the observation point when there is an outside noise reduction device) It was calculated for each frequency band (315 Hz to 2500 Hz). The calculation result is shown in FIG. As shown in the figure, the frequency characteristics of the amount of noise reduction outside the vehicle differ depending on the arrangement example. That is, it was found that in order to reduce a specific frequency band of vehicle exterior noise, the vehicle exterior noise reduction device 1R should be arranged at a position corresponding to the frequency band.

(Second Embodiment)
Next, the vehicle exterior noise reduction device 2 according to the second embodiment of the present invention will be described. The configuration of the vehicle V to which the external noise reduction devices 2L and 2R are applied is the same as that of the first embodiment. The vehicle exterior noise reduction device 2 is composed of a pair of left and right exterior noise reduction devices 2L and 2R. The vehicle exterior noise reduction device 2L on the left side and the vehicle exterior noise reduction device 2R on the right side have symmetrical shapes. Hereinafter, the structure of the vehicle exterior noise reduction device 2R will be described, and the description of the vehicle exterior noise reduction device 2L will be omitted.

The configuration of the vehicle exterior noise reduction device 2R corresponds to a configuration in which the vehicle exterior noise reduction device 1R of the first embodiment is connected in the vehicle width direction. That is, the vehicle exterior noise reduction device 2R has a plurality of (for example, 3 (see FIG. 8) to 5 (see FIG. 10) groove-shaped portions G) extending in the front-rear direction of the vehicle, and these groove-shaped portions G. However, they are arranged side by side in the vehicle width direction.

Here, the relationship between the number and arrangement of the groove-shaped portions G constituting the vehicle exterior noise reduction device 2R on the underfloor surface of the vehicle body VB and the vehicle exterior noise reduction amount was analyzed (computer simulation). The various conditions in the analysis are the same as those in the first embodiment except for the following points regarding the number and arrangement of the groove-shaped portions G.
Arrangement example (F): Arranged so that the side wall portion 12b of the groove portion G at the right end of the vehicle exterior noise reduction device 2R having a configuration in which three vehicle exterior noise reduction devices 1R are connected is located at the origin (see FIG. 9).
Arrangement example (G): Arranged so that the side wall portion 12b of the groove-shaped portion G at the right end of the vehicle exterior noise reduction device 2R having a configuration in which five vehicle exterior noise reduction devices 1R are connected is located at the origin (see FIG. 11). )

Under the above conditions, the amount of outside noise reduction at the observation point (sound pressure of noise at the observation point when there is no outside noise reduction device / sound pressure of noise at the observation point when there is an outside noise reduction device) It was calculated for each frequency band (315 Hz to 2500 Hz). The calculation result is shown in FIG. As shown in the figure, the arrangement example (F) exhibits the same characteristics as the characteristics obtained by superimposing the characteristics of the arrangement examples (A) to the arrangement examples (C), and the arrangement example (G) shows the arrangement example (A). ) To the characteristics equivalent to the characteristics obtained by superimposing the characteristics of the arrangement example (E). That is, in the first embodiment, the amount of noise reduction outside the vehicle in a specific frequency band is improved, but according to the second embodiment, the amount of noise reduction outside the vehicle can be improved over a wider frequency band. I found out.

Furthermore, the practice of the present invention is not limited to the above-described embodiment, and various modifications can be made as long as the object of the present invention is not deviated.

For example, in the above embodiment, the vehicle exterior noise reduction devices 1L and 1R and the vehicle exterior noise reduction devices 2L and 2R are integrally formed of a sound absorbing material. Instead, as shown in FIG. 13, a synthetic resin is used. A groove-shaped portion G may be formed by using a material, and at least a part of a side wall portion Gb thereof may have a sound absorbing portion made of a sound absorbing material. For example, the side wall portion Gb may be composed of a base portion Gb1 made of a synthetic resin material and a plate-shaped sound absorbing member Gb2 made of a sound absorbing material and attached to the inner side surface of the base portion Gb1. In this example, a plurality of through holes are formed in the base Gb1. That is, the base portion Gb1 is formed in a mesh shape. In addition, a plurality of slit-shaped through holes may be formed in the base portion Gb1. Further, the vehicle exterior noise reduction device shown in FIG. 13 may be connected to form an vehicle exterior noise reduction device having a plurality of groove-shaped portions.

Further, the vehicle exterior noise reduction devices 1L and 1R and the vehicle exterior noise reduction devices 2L and 2R may be joined or integrally molded with the ends of the floor undercover UC in the vehicle width direction.

1 (1L, 1R), 2 (2L, 2R) ... External noise reduction device, 11 ... Lower wall part, 12a, 12b ... Side wall part, 13 ... Upper wall part, G ... Groove-shaped part, RL, RR ... Rocker, P1 ... inner rocker panel, P2 ... outer rocker panel, UC ... floor undercover, V ... vehicle, VB ... vehicle body, VC ... cabin, VH ... wheels

Claims (4)

A rocker that reinforces the lower side of the entrance / exit on the side of the vehicle, and has an outer rocker panel that extends in the front-rear direction of the vehicle and has a groove shape that opens inward in the vehicle width direction. An external noise reduction device applied to a vehicle having a rocker in which an inner rocker panel having a groove shape open to the outside in the vehicle width direction is abutted and joined.
A strip-shaped bottom wall extending in the front-rear direction of the vehicle, and extending in the front-rear direction of the vehicle along both ends in the width direction of the bottom wall, and upward from both ends in the width direction of the bottom wall. Each has a groove-shaped portion having a pair of extending side wall portions.
One side wall portion of the pair of side wall portions, the side wall portion located inside in the vehicle width direction includes a sound absorbing portion made of a sound absorbing material, and the other side wall portion of the pair of side wall portions. An external noise reduction device in which a side wall portion is arranged inside in the vehicle width direction with respect to a butt portion between the inner rocker panel and the outer rocker panel. In the vehicle exterior noise reduction device according to claim 1,
An external noise reduction device having a plurality of groove-shaped portions arranged in parallel at predetermined intervals in the vehicle width direction. In the vehicle exterior noise reduction device according to claim 1 or 2.
An external noise reduction device in which the bottom wall portion and the pair of side wall portions are integrally formed by using the sound absorbing material. In the vehicle exterior noise reduction device according to any one of claims 1 to 3.
An external noise reduction device that is joined or integrally molded to an end portion of a floor undercover arranged in a predetermined region including a central portion in the vehicle width direction of the floor surface of the vehicle body in the vehicle width direction.

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