External noise reduction structure

Abstract

To provide a vehicle exterior noise reduction structure capable of reducing vehicle exterior noise. [Solution] An exterior noise reduction structure (70) includes a front fender liner (41) that is provided to face the rear of the vehicle relative to the vehicle tires, and a rocker panel (51) that, together with the front fender liner (41), forms a containment space (Sc11) that can contain sound. The front fender liner (41) is formed with communication holes (410b, 51d) that connect the space around the tire to the containment space (Sc11).

Description

[Technical Field]

[0001] The present invention relates to a vehicle exterior noise reduction structure. [Background technology]

[0002] A conventional vehicle exterior noise reduction structure is described in Patent Document 1 below. The vehicle exterior noise reduction structure described in Patent Document 1 includes a grooved portion having a side wall extending in the longitudinal direction of the vehicle, and a side wall located on the inside in the vehicle width direction. The side wall includes a sound-absorbing portion made of a sound-absorbing material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-160677 Summary of the Invention [Problem to be solved by the invention]

[0004] The vehicle exterior noise reduction structure described in Patent Document 1 leaves room for improvement in terms of the effect of reducing exterior noise caused by tires rolling on the road surface.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle exterior noise reduction structure that is capable of reducing vehicle exterior noise. [Means for solving the problem]

[0006] The vehicle exterior noise reduction structure that solves the above-described problems includes an opposing member provided to face the front or rear of a vehicle tire, and a space forming member that, together with the opposing member, forms a confinement space capable of confining sound. At least one of the opposing member and the space forming member is formed with a first communication hole that connects the space around the tire with the confinement space.

[0007] With this configuration, noise radiated from the tire contact patch enters the containment space through the first communication hole and is contained therein, which prevents noise radiated from the tire contact patch from spreading outside the vehicle, thereby reducing exterior noise. [Effects of the Invention]

[0008] According to the vehicle exterior noise reduction structure of the present invention, it is possible to reduce vehicle exterior noise. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view showing a schematic configuration of a vehicle. [Figure 2] FIG. 2 is a side view schematically showing the structure near the front wheels of the vehicle. [Figure 3] FIG. 2 is a side view schematically showing the structure of the rear wheel and its vicinity of the vehicle. [Figure 4] 1 is a graph showing the energy of noise entering each acoustic space of a vehicle. [Figure 5] 1 is a side view showing a side structure of a vehicle according to a first embodiment. [Figure 6] FIG. 1 is a plan view showing a planar structure of a vehicle according to a first embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a cross-sectional structure taken along line VII-VII in FIG. [Figure 8] FIG. 2 is a perspective view showing the perspective structure of the front fender liner and rocker panel of the first embodiment. [Figure 9] 2 is an enlarged side view showing the side structure near the front wheel of the vehicle according to the first embodiment. FIG. [Figure 10] FIG. 2 is a perspective view showing a rear fender liner and a rocker panel according to the first embodiment. [Figure 11] 2 is an enlarged side view showing the side structure near the rear wheel of the vehicle according to the first embodiment. FIG. [Figure 12] FIG. 10 is an enlarged side view showing a side structure near a front wheel of a vehicle according to a second embodiment. [Figure 13] FIG. 10 is an enlarged side view showing a side structure near a rear wheel of a vehicle according to a second embodiment. [Figure 14]FIG. 11 is an enlarged side view showing a side structure near a front wheel of a vehicle according to a third embodiment. [Figure 15] FIG. 10 is a perspective view showing a perspective structure of a guide plate according to a third embodiment. [Figure 16] FIG. 11 is an enlarged side view showing a side structure near a rear wheel of a vehicle according to a third embodiment. [Figure 17] 11 is a graph showing an example of the relationship between vehicle position and noise level in the third embodiment. [Figure 18] 11 is a graph showing an example of the relationship between vehicle position and noise level in the third embodiment. [Figure 19] 11 is a graph showing an example of the relationship between vehicle position and noise level in the third embodiment. [Figure 20] FIG. 1 is a diagram schematically illustrating an example of a configuration for measuring external vehicle noise. [Figure 21] FIG. 11 is an enlarged side view showing a side structure near a front wheel of a vehicle according to a modified example of the third embodiment. [Figure 22] FIG. 11 is an enlarged side view showing a side structure near a rear wheel of a vehicle according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a vehicle exterior noise reduction structure will be described with reference to the drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0011] <Experimental Results> Before describing the vehicle exterior noise reduction structure of the embodiment, the results of experiments conducted by the inventors of the present application will be described.

[0012] The inventors of the present application experimentally measured noise emitted from the tires of the front and rear wheels while the vehicle was running. Specifically, as shown in FIG. 1 , they performed sound source and path detection of the external noise emitted from each tire when the tires of the front wheels 31 and the rear wheels 33 of the vehicle 10 were rotated by rollers 601, 602 of a chassis dynamometer device 600. As a result, it was found that Pa and Pb shown in FIG. 1 are noise sources. Pa is the contact surface between the tire of the front wheel 31 and the roller 601, and Pb is the contact surface between the tire of the rear wheel 33 and the roller 602. That is, in the vehicle 10, noise is generated from the contact surface between the tire of the front wheel 31 and the ground, and noise is also generated from the contact surface between the tire of the rear wheel 33 and the ground. Hereinafter, Pa will also be referred to as the tire contact surface of the front wheel 31, and Pb will also be referred to as the tire contact surface of the rear wheel 33.

[0013] Meanwhile, experiments conducted by the inventors have revealed that the propagation paths of noise radiated from the tire contact patch Pa of the front wheel 31 are Ra11 to Ra12 and Ra42 to Ra41 shown in FIG. 1. Ra11 indicates the path of noise that propagates from the tire contact patch Pa of the front wheel 31 toward the front side of the vehicle (FR). Ra12 indicates the path of noise that propagates from the tire contact patch Pa of the front wheel 31 toward the space formed between the front fender liner of the vehicle 10 and the front of the tire of the front wheel 31. Ra42 indicates the path of noise that propagates from the tire contact patch Pa of the front wheel 31 toward the space formed between the front fender liner of the vehicle 10 and the rear of the tire of the front wheel 31. Ra41 indicates the path of noise that propagates from the tire contact patch Pa of the front wheel 31 toward the rear of the vehicle (RR). Experiments conducted by the inventors have revealed that the travel paths of noise emitted from the tire contact patch Pb of the rear wheel 33 are similarly Rb11 to Rb12 and Rb42 to Rb41 shown in FIG.

[0014] Next, the inventors calculated approximate values ​​of noise energy Ea1 to Ea4 that enters the acoustic spaces Sd11, Sd21, Sd22, and Sd12 from the tire contact patch Pa of the front wheel 31 via each of the paths Ra11 to Ra12 and Ra42 to Ra41, respectively, as shown in Fig. 2. The acoustic space Sd11 is located in front of the vehicle FR relative to the tire of the front wheel 31, and is a space provided between the body of the vehicle 10 and the ground. The acoustic space Sd21 is located in front of the vehicle FR relative to the tire of the front wheel 31, and is a space provided between the front fender liner of the vehicle 10 and in front of the tire of the front wheel 31. The acoustic space Sd22 is located behind the vehicle RR relative to the tire of the front wheel 31, and is a space provided between the front fender liner of the vehicle 10 and behind the tire of the front wheel 31. The acoustic space Sd12 is located behind the vehicle RR relative to the tire of the front wheel 31, and is a space provided between the body of the vehicle 10 and the ground. Similarly, the inventors calculated approximate values ​​of noise energy Eb1 to Eb4 that invades the acoustic spaces Sd13, Sd23, Sd24, and Sd14 from the tire contact patch Pb of the rear wheel 33 via the paths Rb11 to Rb12 and Rb42 to Rb41, respectively, as shown in Fig. 3. The approximate values ​​of the noise intrusion energies Ea1 to Ea4 and Eb1 to Eb4 can be calculated, for example, from the acoustic intensity of the noise radiated from the tire of the front wheel 31 and the area of ​​the entrance to each of the acoustic spaces Sd11, Sd21, Sd22, and Sd12. The sound radiated from the tire has a noise level of 110 dB and a spectral density of 0.1 W / m when the vehicle 10 is traveling at a speed of 100 km / h in a free sound field, for example. 2 Based on this, when calculating the approximate values ​​of each noise intrusion energy Ea1 to Ea4, Eb1 to Eb4, the acoustic intensity is set to 0.1 W / m 2 4 is a graph showing the approximate values ​​of the intrusion noise energies Ea1 to Ea4 and Eb1 to Eb4 calculated by the inventors.

[0015] 4, when comparing the intrusion noise energies Ea1 to Ea4 and Eb1 to Eb4, it is found that Ea1, Ea4, Eb1, and Eb4 are greater than the other intrusion noise energies Ea2, Ea3, Eb2, and Eb3. Also, when comparing the intrusion noise energies Ea2, Ea3, Eb2, and Eb3, it is found that Ea2 and Ea3 are greater than Eb2 and Eb3.

[0016] Below, the vehicle exterior noise reduction structures of each embodiment constructed based on the results of this experiment will be described.

[0017] First Embodiment First, a first embodiment of the vehicle exterior noise reduction structure will be described.

[0018] (Configuration of vehicle and exterior noise reduction structure) Fig. 5 is a side view showing the left side structure of the vehicle 10 of the first embodiment. Fig. 6 is a plan view showing the plan structure of the vehicle 10 of the first embodiment. Note that, hereinafter, the forward direction of the vehicle is indicated by the symbol FR, the rearward direction of the vehicle is indicated by the symbol RR, the rightward direction of the vehicle is indicated by the symbol RH, and the leftward direction of the vehicle is indicated by the symbol LH. Furthermore, the fore-aft direction of the vehicle is indicated by the symbol FB, and the left-right direction of the vehicle is indicated by the symbol RL.

[0019] 5 and 6, the vehicle 10 includes a body 20 and wheels 31 to 34. The wheels 31 to 34 are connected to axles (not shown) and are rotatably supported on the vehicle body 20 via the axles. The vehicle body 20 includes a front bumper 21, a front fender panel 22, a rear bumper 23, a rear fender panel 24, fender liners 41 to 44, and rocker panels 51 and 52. The front bumper 21, the front fender panel 22, the rear bumper 23, the rear fender panel 24, the fender liners 41 to 44, and the rocker panels 51 and 52 are examples of components used in the vehicle body 20.

[0020] The front bumper 21 is made of, for example, synthetic resin, and constitutes the front lower end of the vehicle body 20. The front fender panel 22 is made of, for example, metal, and is provided on the front side of the vehicle 10 in the vehicle width direction so as to be continuous with the front bumper 21. The front bumper 21 and the front fender panel 22 constitute part of the outer covering of the vehicle body 20. Wheel arch portions 21a, 22a, which are arc-shaped and follow the outer shape of the tire of the left front wheel 31, are formed on the outer edge of the front bumper 21 and the outer edge of the front fender panel 22, respectively. The wheel arch portions 21a, 22a form a wheel arch 47. A front wheel house 45, in which the tire of the left front wheel 31 is disposed, is formed inside the wheel arch 47.

[0021] The rear bumper 23 is made of, for example, synthetic resin and constitutes the rear lower end of the vehicle body 20. The rear fender panel 24 is made of, for example, metal and is provided on the rear side of the vehicle 10 in the vehicle width direction so as to be continuous with the rear bumper 23. Wheel arch portions 23a, 24a, which are arc-shaped and follow the outer shape of the tire of the left rear wheel 33, are formed on the outer edge of the rear bumper 23 and the outer edge of the rear fender panel 24, respectively. The wheel arch portions 23a, 24a form a wheel arch 48. A rear wheel house 46 in which the tire of the left rear wheel 33 is disposed is formed inside the wheel arch 48.

[0022] The rocker panels 51, 52 are formed to extend in the vehicle fore-and-aft direction FB along the lower edges of the openings OL, OR of the vehicle 10. The openings OL, OR are provided as entrances and exits on the left and right sides of the vehicle 10. The rocker panels 51, 52 are joined to the floor panel and reinforce the lower portions of the openings OL, OR. FIG. 7 is a cross-sectional view showing the cross-sectional structure taken along line VII-VII in FIG. 6. As shown in FIG. 7, the cross-section of the rocker panel 51 perpendicular to the vehicle fore-and-aft direction FB is cylindrical. A space Sc11 is formed inside the rocker panel 51 and extends in the vehicle fore-and-aft direction FB. The rocker panel 51 is fixed to the floor panel 26. The rocker panel 52 has a structure similar to that of the rocker panel 51, and has an internal space extending in the vehicle fore-and-aft direction FB.

[0023] As shown in Figures 5 and 6, front fender liner 41 is provided on the inner surface of front wheel house 45 and is formed in a semicircular arc shape so as to cover the area above left front wheel 31. Front fender liner 41 is made of, for example, synthetic resin. Front fender liner 41 is attached and fixed at multiple points to front bumper 21 and front fender panel 22. Front fender liner 41 is a member for catching mud, water, snow, etc. that is thrown up by the tire of left front wheel 31. As shown in Figure 8, front fender liner 41 has a main body portion 410 and lower wall portions 411, 412.

[0024] The main body 410 is curved in a semicircular arc so as to cover the tire of the left front wheel 31 from above. Reference numeral 410c shown in Fig. 8 indicates the front end portion of the main body 410 located at the front side of the vehicle FR. Reference numeral 410d indicates the rear end portion of the main body 410 located at the rear side of the vehicle RR. The front end portion 51a of the rocker panel 51 is arranged to face the portion of the main body 410 on the rear side of the vehicle RR.

[0025] The lower wall portion 411 is formed to extend from a front end portion 410c of the main body portion 410 toward the front side of the vehicle FR. As shown in Fig. 9, a space Sb11 formed inside the vehicle body 20 is defined by the vehicle front side portion of the main body portion 410, the lower wall portion 411, and the front bumper 21. The lower wall portion 411 has a plurality of communication holes 411a that communicate between the exterior space Sd11 located below the lower wall portion 411 and the interior space Sb11. The front end portion 410c of the main body portion 410 has a plurality of communication holes 410a that communicate between the front wheel house 45 and the interior space Sb11.

[0026] The lower wall portion 412 is formed to extend from the rear end portion 410d of the main body portion 410 toward the vehicle rear RR. A bottom wall portion of the front end portion 51b of the rocker panel 51 is joined to the upper surface of the lower wall portion 412. Communication holes 412a, 51d are formed in the lower wall portion 412 and the bottom wall portion of the front end portion 51b of the rocker panel 51, respectively, to communicate between the exterior space Sd12 located below and the internal space Sc11 of the rocker panel 51. Communication holes 410b, 51d are formed in the rear end portion 410d of the main body portion 410 and the front end portion 51a of the rocker panel 51, respectively, to communicate between the front wheel house 45 and the internal space Sc11 of the rocker panel 51.

[0027] 5 and 6, rear fender liner 43 is provided on the inner surface of rear wheel house 46 and is formed in a semicircular arc shape so as to cover the area above left rear wheel 33. Rear fender liner 43 is made of, for example, synthetic resin. Rear fender liner 43 is attached in a fixed state at multiple points to rear bumper 23 and rear fender panel 24. Like front fender liner 41, rear fender liner 43 is a member for receiving mud and the like kicked up by the tire of left rear wheel 33, and as shown in FIG. 10, has a main body portion 430 and a lower wall portion 431.

[0028] The main body 430 is curved in a semicircular arc so as to cover the tire of the left rear wheel 33 from above. Reference numeral 430c shown in Fig. 10 indicates the front end portion of the main body 430 located at the front side of the vehicle FR. Reference numeral 430d indicates the rear end portion of the main body 430 located at the rear side of the vehicle RR. The rear end portion 51c of the rocker panel 51 is disposed to face the portion of the main body 430 on the front side of the vehicle FR.

[0029] The lower wall portion 431 is formed to extend from the front end portion 430c of the main body portion 430 toward the front side FR of the vehicle. A bottom wall portion of the rear end portion 51e of the rocker panel 51 is joined to the upper surface of the lower wall portion 431. As shown in FIG. 11 , communication holes 431a, 51f are formed in the lower wall portion 431 and the bottom wall portion of the rear end portion 51e of the rocker panel 51, respectively, to communicate between the exterior space Sd13 located below and the interior space Sc11 of the rocker panel 51. Communication holes 430a, 51f are formed in the front end portion 430c of the main body portion 430 and the rear end portion 51c of the rocker panel 51, respectively, to communicate between the rear wheel house 46 and the interior space Sc11 of the rocker panel 51.

[0030] As shown in FIGS. 10 and 11 , the rear bumper 23 has a cylindrical rear side undercover 25. A space Se11 is formed inside the rear side undercover 25. The rear side undercover 25 has an opening 25a that opens to the rear wheel well 46. The opening 25a is closed by a bumper seal 60 made of synthetic resin. A rear end 430d of the main body 430 of the rear fender liner 43 is joined to an upper wall portion of the opening 25a in the rear side undercover 25. A communication hole 25c is formed in the rear side undercover 25, connecting the exterior space Sd14 located below the rear side undercover 25 with the interior space Se11 of the rear side undercover 25. A communication hole 60a is formed in the bumper seal 60, connecting the rear wheel well 46 with the interior space Se11 of the rear side undercover 25. The bumper seal 60 is an example of a member used in the vehicle body 20.

[0031] In the vehicle 10 of this embodiment, the vehicle exterior noise reduction structure 70 that reduces noise radiated from the tire contact patch Pa of the left front wheel 31 is made up of the front bumper 21, the front fender liner 41, and the rocker panel 51. In addition, the vehicle exterior noise reduction structure 70 that reduces noise radiated from the tire contact patch Pb of the left rear wheel 33 is made up of the rear side undercover 25, the bumper seal 60, the rear fender liner 43, and the rocker panel 51.

[0032] Next, the operation and effect of the vehicle exterior noise reduction structure 70 will be described.

[0033] As shown in FIG. 9 , in the vehicle 10 of this embodiment, part or all of the noise radiated from the tire contact patch Pa of the left front wheel 31 traveling in the direction indicated by the arrow Ra11 in the figure enters the interior space Sb11 through the exterior space Sd11 and the communication hole 411a of the front fender liner 41. Because the interior space Sb11 is an acoustically closed space inside the vehicle body 20, the noise traveling along path Ra11 is confined within the interior space Sb11. This prevents part or all of the noise traveling along path Ra11 from radiating outside the vehicle. Note that an acoustically closed space does not necessarily refer to a spatially closed space, such as an airtight space, but rather refers to a space in which sound that enters the interior is unlikely to be released to the outside, in other words, a space in which sound can be confined.

[0034] Furthermore, noise radiated from the tire contact patch Pa of the left front wheel 31 traveling in the direction indicated by the arrow Ra12 in the figure enters the internal space Sb11 through the front wheel house 45 and the communication hole 410a of the front fender liner 41. Therefore, the noise on path Ra12 is also confined within the internal space Sb11 of the vehicle body 20. Therefore, it is possible to similarly prevent some or all of the noise on path Ra12 from being radiated outside the vehicle.

[0035] Furthermore, noise radiated from the tire contact patch Pa of the left front wheel 31 traveling in the direction indicated by arrow Ra41 in the figure enters internal space Sc11 of rocker panel 51 through external space Sd12, communication hole 412a formed in front fender liner 41, and communication hole 51d formed in rocker panel 51. Because internal space Sc11 is an acoustically closed space inside rocker panel 51, the noise on path Ra41 is also confined within internal space Sc11 of rocker panel 51. Therefore, it is possible to similarly prevent some or all of the noise on path Ra41 from being radiated outside the vehicle.

[0036] Furthermore, noise radiated from the tire contact patch Pa of the left front wheel 31 traveling in the direction indicated by arrow Ra42 in the figure enters the internal space Sc11 of the rocker panel 51 through the front wheel house 45, the communication hole 410b of the front fender liner 41, and the communication hole 51d formed in the rocker panel 51. Therefore, the noise on path Ra42 is also confined within the internal space Sc11. This similarly prevents some or all of the noise on path Ra42 from being radiated outside the vehicle.

[0037] 11 , some or all of the noise radiating from the tire contact patch Pb of the left rear wheel 33 and traveling in the direction indicated by arrow Rb11 in the figure is confined in the internal space Sc11 of the rocker panel 51 through the exterior space Sd13, the communication hole 431a of the rear fender liner 43, and the communication hole 51f of the rocker panel 51. Furthermore, some or all of the noise traveling in the direction indicated by arrow Rb12 is confined in the internal space Sc11 of the rocker panel 51 through the communication hole 430a of the rear fender liner 43 and the communication hole 51f of the rocker panel 51. Furthermore, some or all of the noise traveling in the direction indicated by arrow Rb41 is confined in the internal space Se11 of the rear side undercover 25 through the communication hole 25c of the rear side undercover 25. Furthermore, some or all of the noise traveling in the direction indicated by arrow Rb42 is confined in the internal space Se11 of the rear side undercover 25 through the communication hole 60a of the bumper seal 60. Therefore, it is possible to similarly prevent some or all of the noises radiated from the tire contact patch Pb of the left rear wheel 33 along the paths Rb11, Rb12, Rb41, and Rb42 from being radiated outside the vehicle.

[0038] The peripheral structures of the front fender liner 42 and the rear fender liner 44 are the same as or similar to the peripheral structures of the front fender liner 41 and the rear fender liner 43, respectively, and therefore a description of these structures will be omitted.

[0039] (Actions and Effects of the Vehicle Exterior Noise Reduction Structure of the Present Embodiment) As described above, the vehicle exterior noise reduction structure 70 includes the front bumper 21, front fender liners 41, 42, and rocker panels 51, 52. The front fender liners 41, 42 are an example of opposing members provided to face the front and rear tires of the front wheels 31, 32 of the vehicle 10, respectively. The front bumper 21, together with the front fender liners 41, 42, is an example of a space-forming member that forms a containment space Sb11 capable of containing sound. The rocker panels 51, 52 are an example of a space-forming member that forms a containment space Sc11 capable of containing sound. Communication holes 410a, 410b, 51d are formed in portions of the front fender liners 41, 42 that face the tires of the front wheels 31, 32, respectively, to communicate the spaces around the tires with the containment spaces Sb11, Sc11. In this embodiment, the communication holes 410a, 410b, 51d are an example of first communication holes.

[0040] With this configuration, noise radiated from the tire contact surfaces Pa of the front wheels 31, 32 enters the confinement spaces Sb11, Sc11 through the communication holes 410a, 410b, 51d and is confined therein. This prevents the noise radiated from the tire contact surfaces Pa from spreading outside the vehicle, thereby reducing outside noise.

[0041] The exterior noise reduction structure 70 further includes a rear side undercover 25, a bumper seal 60, rear fender liners 43, 44, and rocker panels 51, 52. The rear fender liners 43, 44 are an example of opposing members provided to face the front (FR) of the vehicle relative to the tires of the rear wheels 33, 34 of the vehicle 10. The bumper seal 60 is an example of an opposing member provided to face the rear (RR) of the tires of the rear wheels 33, 34 of the vehicle 10 and closes the opening 25a of the rear side undercover 25. The rear bumper 23 and the rear side undercover 25, together with the bumper seal 60, are an example of a space forming member that forms a containment space Se11 that can contain sound. Communication holes 430a, 51f are formed in the rear fender liners 43, 44 in the portions facing the tires of the rear wheels 33, 34, respectively, to communicate the space around the tires with the containment space Sc11. Communication holes 60a that connect the space around the tires to the confined space Se11 are formed in the bumper seal 60 in portions facing the tires of the rear wheels 33, 34. In this embodiment, the communication holes 430a, 51f, 60a are examples of first communication holes.

[0042] With this configuration, noise radiated from the tire contact surfaces Pb of the rear wheels 33 and 34 enters and is confined in the confinement spaces Sc11 and Se11 through the communication holes 430a, 51f, and 60a. This prevents noise radiated from the tire contact surfaces Pb from spreading outside the vehicle, thereby reducing exterior noise.

[0043] The front fender liner 41 has a semicircular arc-shaped main body portion 410 provided around the tire, a lower wall portion 411 formed to extend from a front end portion 410c of the main body portion 410 toward the vehicle front (FR), and a lower wall portion 412 formed to extend from a rear end portion 410d of the main body portion 410 toward the vehicle rear (RR). Communication holes 410a and 410b are formed in the main body portion 410. A communication hole 411a is formed in the lower wall portion 411, which connects the exterior space Sd11 below the lower wall portion 411 with the confined space Sb11. A communication hole 412a is formed in the lower wall portion 412, which connects the exterior space Sd12 below the lower wall portion 412 with the confined space Sc11. In this embodiment, the communication holes 411a and 412a are examples of fourth communication holes. Further, a communication hole 51d is formed in the rocker panels 51, 52, which communicates the exterior space Sd12 below the rocker panels 51, 52 and the space around the tire with the confined space Sc11. In the present embodiment, the communication hole 51d is an example of a second communication hole.

[0044] With this configuration, noise radiated from the tire contact surfaces Pa of the front wheels 31, 32 enters the confinement spaces Sb11, Sc11 through the communication holes 411a, 412a, 51d and is confined therein. This further prevents noise radiated from the tire contact surfaces Pa from spreading outside the vehicle, thereby enabling more accurate reduction of outside noise.

[0045] The rear fender liner 43 has a semicircular main body portion 430 provided around the tire and a lower wall portion 431 formed to extend from a front end portion 430c of the main body portion 430 toward the vehicle front FR. A communication hole 430a is formed in the main body portion 430. A communication hole 431a is formed in the lower wall portion 431, which connects the vehicle exterior space Sd13 below the lower wall portion 431 with the confined space Sc11. In this embodiment, the communication hole 431a is an example of a fourth communication hole. Further, a communication hole 51f is formed in the rocker panels 51, 52, which connects the vehicle exterior space Sd13 and the rear space below the rocker panels 51, 52 with the confined space Sc11. Furthermore, a communication hole 25c is formed in the rear side undercover 25, which connects the vehicle exterior space Sd14 below the rear side undercover 25 with the confined space Se11. In this embodiment, the communication hole 51f is an example of a second communication hole, and the communication hole 25c is an example of a third communication hole.

[0046] With this configuration, noise radiated from the tire contact surfaces Pb of the rear wheels 33, 34 enters the containment spaces Sc11, Se11 through the communication holes 430a, 431a, 51f, 60a, 25c and is further confined therein. This further prevents noise radiated from the tire contact surfaces Pb from spreading outside the vehicle, thereby enabling more accurate reduction of outside noise.

[0047] Second Embodiment Next, a second embodiment of the vehicle exterior noise reduction structure 70 will be described. The following description will focus on the differences from the vehicle exterior noise reduction structure 70 of the first embodiment.

[0048] (Exterior noise reduction structure) 12, the vehicle exterior noise reduction structure 70 of this embodiment further includes a sound absorbing member 80 arranged above the lower wall portion 411 of the front fender liner 41, and a sound absorbing member 81 arranged inside the rocker panel 51 near the front end portion 51b. The sound absorbing members 80 and 81 are arranged in the confinement spaces Sb11 and Sc11, respectively.

[0049] 13, the vehicle exterior noise reduction structure 70 of this embodiment further includes a sound absorbing member 82 arranged inside the vicinity of the rear end portion 51e of the rocker panel 51, and a sound absorbing member 83 arranged inside the rear side undercover 25. The sound absorbing members 82 and 83 are arranged in the confinement spaces Sc11 and Se11, respectively.

[0050] A sound-absorbing material, such as a material made of polyester fiber, can be used for the sound-absorbing members 80 to 83. As the polyester fiber, Sekiso Acoustic Fiber (SAF), a product name manufactured by Sekiso Corporation, can be used.

[0051] The rocker panel 52 has a similar structure.

[0052] (Actions and Effects of the Vehicle Exterior Noise Reduction Structure of the Present Embodiment) As described above, the vehicle exterior noise reduction structure 70 includes sound-absorbing members 80-83 arranged in the confinement spaces Sb11, Sc11, and Se11, respectively. In this embodiment, the sound-absorbing members 80-83 are an example of first sound-absorbing members. With this configuration, noise that has entered the confinement spaces Sb11, Sc11, and Se11 is absorbed by the sound-absorbing members 80-83, thereby further preventing the noise from spreading outside the vehicle. This makes it possible to more accurately reduce vehicle exterior noise.

[0053] Third Embodiment Next, a third embodiment of the vehicle exterior noise reduction structure 70 will be described. The following description will focus on the differences from the vehicle exterior noise reduction structure 70 of the second embodiment.

[0054] (Exterior noise reduction structure) As shown in FIG. 14, the vehicle exterior noise reduction structure 70 of this embodiment further includes a guide plate 90 and a cover member 100 that are integrally attached to the bottom surface of the lower wall portion 411 of the front fender liner 41.

[0055] FIG. 15 is a perspective view showing the structure of the guide plate 90. As shown in FIGS. 14 and 15, the guide plate 90 is formed so that its width in the vehicle vertical direction gradually increases toward the vehicle rear RR, and has a generally triangular cross section. The guide plate 90 is hollow inside. A rear opening 900 that opens toward the tire of the left front wheel 31 is formed in the portion of the guide plate 90 toward the vehicle rear RR. The width Ha of the rear opening 900 in the vehicle vertical direction shown in FIG. 14 is set to 30 mm, for example. A similar upper opening 901 is also formed in the portion of the guide plate 90 on the upper side of the vehicle. As shown in FIG. 14, the upper opening 901 of the guide plate 90 faces the communication hole 411a in the lower wall portion 411 of the front fender liner 41. Therefore, the internal space Sb11 of the vehicle body 20 is connected to the space formed between the guide plate 90 and the tire of the left front wheel 31 through the communication hole 411a in the lower wall portion 411 of the front fender liner 41, the upper opening 901 of the guide plate 90, the internal space of the guide plate 90, and the rear opening 900 of the guide plate 90.

[0056] 14, the cover member 100 is provided to cover the communication hole 410a of the front fender liner 41 and the rear opening 900 of the guide plate 90. The cover member 100 is formed of a material that allows sound to pass through but is impervious to water, sand, and other foreign matter, such as a porous material such as nonwoven fabric. The cover member 100 is provided to prevent water, sand, and other foreign matter that is kicked up by the tire of the left front wheel 31 while the vehicle 10 is traveling from entering the interior space Sb11 of the vehicle body 20 through the communication hole 410a of the front fender liner 41 and the rear opening 900 of the guide plate 90.

[0057] As shown in FIG. 14 , the vehicle exterior noise reduction structure 70 further includes a guide plate 91 and a cover member 101 that are integrally attached to the bottom surfaces of the lower wall portion 412 of the front fender liner 41 and the lower wall portion of the rocker panel 51. The guide plate 91 has a shape similar to that of the guide plate 90, with a substantially triangular cross section. The guide plate 91 is formed so that its width in the vehicle up-down direction gradually increases toward the front (FR) of the vehicle. A front opening 910 that opens toward the left front wheel 31 is formed in the portion of the guide plate 91 toward the front (FR) of the vehicle. The width Hb of the front opening 910 in the vehicle up-down direction is set to, for example, 30 mm. A similar upper opening 911 is formed in the upper portion of the guide plate 91. The upper opening 911 faces the communication hole 412a in the lower wall portion 412 of the front fender liner 41 and the communication hole 51d in the rocker panel 51. Therefore, the internal space Sc11 of the rocker panel 51 is connected to the space formed between the guide plate 91 and the tire of the left front wheel 31 through the communication hole 51d of the rocker panel 51, the communication hole 412a of the lower wall portion 412 of the front fender liner 41, the upper opening 911 of the guide plate 91, the internal space of the guide plate 91, and the front opening 910 of the guide plate 91.

[0058] The cover member 101 is provided so as to cover the communication hole 410b of the front fender liner 41 and the front opening 910 of the guide plate 91. Like the cover member 100, the cover member 101 is also made of nonwoven fabric or the like.

[0059] As shown in FIG. 16, the vehicle exterior noise reduction structure 70 further includes a guide plate 92 and a cover member 102 that are integrally attached to the bottom surfaces of the lower wall portion 431 of the rear fender liner 43 and the lower wall portion of the rocker panel 51.

[0060] 15 , and has a rear opening 920 that opens toward the left rear wheel 33, and an upper opening 921 that opens toward the communication hole 431a in the lower wall portion 431 of the rear fender liner 43 and the communication hole 51f in the rocker panel 51. The width Hc of the rear opening 920 in the vehicle's up-down direction is set to, for example, 40 mm. The internal space Sc11 of the rocker panel 51 is in communication with the space formed between the guide plate 92 and the tire of the left rear wheel 33 through the communication hole 51f in the rocker panel 51, the communication hole 431a in the lower wall portion 431 of the rear fender liner 43, the upper opening 921 of the guide plate 92, the internal space of the guide plate 92, and the rear opening 920 of the guide plate 92.

[0061] The cover member 102 is provided so as to cover the communication hole 430a of the rear fender liner 43 and the rear opening 920 of the guide plate 92. Like the cover member 100, the cover member 102 is also made of nonwoven fabric or the like.

[0062] As shown in FIG. 16, the vehicle exterior noise reduction structure 70 further includes a guide plate 93 and a cover member 103 that are integrally attached to the bottom surface of the lower wall portion of the rear side undercover 25 .

[0063] 15 , and has a front opening 930 that opens toward the left rear wheel 33, and an upper opening 931 that opens toward the communication hole 25c of the rear side undercover 25. The width Hd of the front opening 930 in the vehicle's up-down direction is set to, for example, 40 mm. The internal space Se11 of the rear side undercover 25 is in communication with the space formed between the guide plate 93 and the tire of the left rear wheel 33 through the communication hole 25c of the rear side undercover 25, the upper opening 931 of the guide plate 93, the internal space of the guide plate 93, and the front opening 930 of the guide plate 93.

[0064] The cover member 103 is provided so as to cover the communication hole 60a of the bumper seal 60 and the front opening 930 of the guide plate 93. Like the cover member 100, the cover member 103 is also made of nonwoven fabric or the like.

[0065] The peripheral structures of the front fender liner 42 and the rear fender liner 44 are the same as or similar to the peripheral structures of the front fender liner 41 and the rear fender liner 43, respectively, and therefore a description of these structures will be omitted.

[0066] (Actions and Effects of the Vehicle Exterior Noise Reduction Structure of the Present Embodiment) As described above, the vehicle exterior noise reduction structure 70 of this embodiment has guide plates 90-93. The guide plate 90 is provided below the lower wall portion 411 of the front fender liners 41, 42, and is a hollow member that guides sound from the space around the tires of the front wheels 31, 32 toward the communication hole 411a in the lower wall portion 411 of the front fender liners 41, 42. The guide plate 91 is provided below the lower wall portion 412 of the front fender liners 41, 42 and the rocker panels 51, 52, and is a hollow member that guides sound from the space around the tires of the front wheels 31, 32 toward the communication hole 412a in the lower wall portion 412 of the front fender liners 41, 42 and the communication hole 51d in the rocker panels 51, 52. The guide plate 92 is provided below the lower wall portion 431 of the rear fender liners 43, 44 and the rocker panels 51, 52, and is a hollow member that guides sound from the space around the tires of the rear wheels 33, 34 toward the communication hole 431a in the lower wall portion 431 of the rear fender liners 43, 44 and the communication hole 51f in the rocker panels 51, 52. The guide plate 93 is provided below the rear side undercover 25, and is a hollow member that guides sound from the space around the tires of the rear wheels 33, 34 toward the communication hole 25c in the rear side undercover 25. In this embodiment, the guide plates 90 to 92 are an example of a third guide plate. The guide plates 91, 92 are also an example of a first guide plate. Furthermore, the guide plate 93 is an example of a second guide plate.

[0067] With this configuration, noise radiated from the tire contact surfaces Pa of the front wheels 31, 32 and the tire contact surfaces Pb of the rear wheels 33, 34 can more easily enter the confinement spaces Sb11, Sc11, Se11 through the guide plates 90-93, thereby preventing the noise radiated from the tire contact surfaces Pa, Pb from spreading outside the vehicle, thereby more accurately reducing outside noise.

[0068] 17 to 19 show experimental measurements of noise detected outside the vehicle when the vehicle exterior noise reduction structure 70 of this embodiment is used. Fig. 20 shows an outline of the experiment conducted by the inventors.

[0069] As shown in FIG. 20, in an experiment conducted by the inventors, when the tires of the wheels 31 to 34 of the vehicle 10 were rotated on a chassis dynamometer, the magnitude of the external noise radiated from each tire was measured using microphone devices M1 to M2. 13 In FIG. 20, the position O set in front of the vehicle 10 is set as the origin (0,0), the axis parallel to the longitudinal direction of the vehicle 10 is indicated by the x-axis, and the axis parallel to the lateral direction of the vehicle 10 is indicated by the y-axis. The positive direction of the x-axis is set to the rear direction of the vehicle 10, and the negative direction of the x-axis is set to the front direction of the vehicle 10. The positive direction of the y-axis is set to the right direction of the vehicle 10, and the negative direction of the y-axis is set to the left direction of the vehicle 10. Microphone devices M1 to M 13 are arranged side by side on axis m10. Axis m10 is a line that is spaced a predetermined distance L from the center of the vehicle 10 in the y-axis direction and is parallel to the x-axis. Note that distance L is set to 7.5 m by regulation.

[0070] In Figure 17, the dashed dotted line shows the measurement results of the external noise when only guide plate 90 corresponding to front wheels 31, 32 is provided on vehicle 10, and the solid line shows the measurement results of the external noise when guide plates 90-93 are not provided on vehicle 10. As shown in Figure 17, when guide plate 90 is provided on vehicle 10, it is possible to reduce the noise level detected when the vehicle position is near 0 m, i.e., the noise level detected on the side of vehicle 10, by about 0.2 dB compared to when guide plates 90-93 are not provided on vehicle 10.

[0071] In Figure 18, the dashed dotted line shows the measurement results of the external noise when only guide plate 93 corresponding to rear wheels 33, 34 is provided on vehicle 10, and the solid line shows the measurement results of the external noise when guide plates 90-93 are not provided on vehicle 10. As shown in Figure 18, when guide plate 93 is provided on vehicle 10, it is possible to reduce the noise level detected near a vehicle position of 0 m, i.e., the noise level detected to the side of vehicle 10, by about 0.1 dB compared to when guide plates 90-93 are not provided on vehicle 10. When guide plate 93 is provided on vehicle 10, it is possible to effectively reduce the noise level, particularly in areas where the vehicle is 6 m or more away.

[0072] In Figure 19, the dashed dotted line shows the measurement results of the external noise when the vehicle 10 is provided with guide plates 91, 92 for each of the wheels 31-34, and the solid line shows the measurement results of the external noise when the vehicle 10 is not provided with guide plates 90-93. As shown in Figure 19, when the vehicle 10 is provided with guide plates 91, 92, the noise level detected at a vehicle position of approximately 3 m, i.e., the noise level detected at the side of the vehicle 10, can be reduced by approximately 0.1 dB compared to when the vehicle 10 is not provided with guide plates 90-93.

[0073] On the other hand, the vehicle exterior noise reduction structure 70 of this embodiment further includes cover members 100 to 103 having a porous structure. The cover member 100 is provided at the opening of the communication hole 410a in the front fender liner 41 and the opening of the guide plate 90. The cover member 101 is provided at the opening of the communication hole 410b in the front fender liner 41 and the opening of the guide plate 91. The cover member 102 is provided at the opening of the communication hole 430a in the rear fender liner 43 and the opening of the guide plate 92. The cover member 103 is provided at the opening of the communication hole 60a in the bumper seal 60 and the opening of the guide plate 93. In this embodiment, the cover members 101 and 102 are examples of first cover members, the cover member 103 is an example of a second cover member, and the cover members 100 to 102 are examples of third cover members. The cover members 100 to 103 are also examples of fourth cover members.

[0074] This configuration can prevent foreign matter such as water and sand kicked up by the wheels 31 to 34 from entering the confinement spaces Sb11, Sc11, and Se11.

[0075] (Variation) Next, a modified example of the vehicle exterior noise reduction structure 70 of the third embodiment will be described.

[0076] In the vehicle exterior noise reduction structure 70 of this modified example, as shown in Fig. 21 , sound-absorbing members 110 are provided on the bottom and top surfaces of the lower wall portion of the guide plate 90. Similarly, sound-absorbing members 111 are provided on the bottom and top surfaces of the lower wall portion of the guide plate 91. Furthermore, as shown in Fig. 22 , sound-absorbing members 112 and 113 are similarly provided on the bottom and top surfaces of the lower wall portions of the guide plates 92 and 93, respectively. The sound-absorbing members 110 to 113 can be made of a material capable of absorbing noise, such as a material made of polyester fiber such as SAF. In this modified example, the sound-absorbing members 111 and 112 are examples of second sound-absorbing members, the sound-absorbing member 113 is an example of a third sound-absorbing member, and the sound-absorbing members 110 to 112 are examples of fourth sound-absorbing members.

[0077] With this configuration, noise radiated from the tire contact surfaces Pa of the front wheels 31, 32 and the tire contact surfaces Pb of the rear wheels 33, 34 is absorbed by the sound absorbing members 110-113 as it passes through the guide plates 90-93, and sound reflection caused when the guide plates contract is prevented, so that noise radiated from the tire contact surfaces Pa, Pb can be prevented from spreading outside the vehicle, thereby more accurately reducing outside noise.

[0078] In Figure 19, the two-dot chain line shows the measurement results of external noise when guide plates 91, 92 are provided on vehicle 10 and sound-absorbing members 111, 112 are also provided on guide plates 91, 92. As shown by the two-dot chain line in Figure 19, when sound-absorbing members 111, 112 are provided on guide plates 91, 92, it is possible to reduce the noise level detected at a vehicle position of approximately 3 m, i.e., the noise level detected on the side of vehicle 10, by approximately 0.4 dB compared to when guide plates 91, 92 are not provided on vehicle 10.

[0079] Note that a sound absorbing material may be provided on only one of the bottom surface and the top surface of the lower wall portion of each of the guide plates 90 to 93. Furthermore, the guide plates 90 to 93 themselves may be made of a sound absorbing material.

[0080] <Other embodiments> The present disclosure is not limited to the above specific examples.

[0081] For example, the characteristic structures of the vehicle exterior noise reduction structure 70 of each embodiment can be adopted individually. Specifically, the vehicle exterior noise reduction structure 70 of the third embodiment does not have to be provided with the sound absorbing members 80 to 83. Furthermore, in the vehicle exterior noise reduction structure 70 of the third embodiment, the front fender liner 41 does not have to be provided with the communication holes 410a, 410b, and the rear fender liner 43 and the bumper seal 60 do not have to be provided with the communication holes 430a, 60a.

[0082] Furthermore, the communication holes 410a, 410b, 430a, etc. of the first embodiment may be replaced with wire mesh, slits, punched metal, nonwoven fabric, etc. Here, nonwoven fabric refers to a material that appears to have no holes but allows sound to pass through.

[0083] Design modifications made by a person skilled in the art to the above specific examples as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of each of the above specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above specific examples can be combined as appropriate as long as no technical contradictions arise. [Explanation of symbols]

[0084] Sb11, Sc11, Se11: confinement space, 10: vehicle, 20: body, 21: front bumper (space forming member), 23: rear bumper (space forming member), 25: rear side undercover (space forming member), 25c: communication hole (third communication hole), 41, 42: front fender liner (opposing member), 43, 44: rear fender liner (opposing member), 51, 52: rocker panel (space forming member), 51d, 51f: communication hole (second communication hole), 60: bumper seal (opposing member), 410a, 410b, 430a, 60a: communication hole (first communication hole), 70: exterior noise reduction structure, 80 to 83: sound absorbing member (first sound-absorbing member), 90-92: guide plate (third guide plate), 91, 92: guide plate (first guide plate), 93: guide plate (second guide plate), 100: cover member (third cover member, fourth cover member), 101, 102: cover member (first cover member, third cover member, fourth cover member), 103: cover member (second cover member, fourth cover member), 110: sound-absorbing member (fourth sound-absorbing member), 111, 112: sound-absorbing member (second sound-absorbing member, fourth sound-absorbing member), 113: sound-absorbing member (third sound-absorbing member), 410, 430: main body portion, 411, 431: lower wall portion, 411a, 412a, 431a: communication hole (fourth communication hole).

Claims

1. a first opposing member provided to face a first tire of the vehicle in a front or rear direction of the vehicle; a second opposing member provided to face a second tire other than the first tire of the vehicle in a front or rear direction of the vehicle; a space forming member that forms a single containment space capable of containing sound; a first communication hole that communicates a space around the first tire with the confined space is formed in the first opposing member; The second opposing member is formed with a second communication hole that communicates the space around the second tire with the confined space. External noise reduction structure.

2. a first sound absorbing member disposed in the enclosed space; The vehicle exterior noise reduction structure according to claim 1.

3. The space forming member includes a member used in the body of the vehicle. The vehicle exterior noise reduction structure according to claim 1.

4. The member used in the body of the vehicle includes at least one of a front bumper, a rocker panel, and a rear bumper of the vehicle. The vehicle exterior noise reduction structure according to claim 1.

5. The rocker panel is formed with a third communication hole that communicates the enclosed space with an exterior space below the rocker panel and a space around the first tire or the second tire. The vehicle exterior noise reduction structure according to claim 4.

6. a first guide plate provided below the rocker panel for guiding sound from a space around the first tire or the second tire toward the third communication hole. The vehicle exterior noise reduction structure according to claim 5.

7. The sound absorbing member further includes a second sound absorbing member provided on the first guide plate. The vehicle exterior noise reduction structure according to claim 6.

8. a first cover member having a porous structure, the first cover member being provided at an opening in the first guide plate that opens into a space around the first tire or the second tire; The vehicle exterior noise reduction structure according to claim 6.

9. The rear bumper is formed with a fourth communication hole that communicates the enclosed space with an exterior space below the rear bumper. The vehicle exterior noise reduction structure according to claim 4.

10. a hollow second guide plate provided below the rear bumper and configured to guide sound from a space around the first tire or the second tire toward the fourth communication hole. The vehicle exterior noise reduction structure according to claim 9.

11. The sound absorbing member further includes a third sound absorbing member provided on the second guide plate. The vehicle exterior noise reduction structure according to claim 10.

12. a second cover member having a porous structure, the second cover member being provided at an opening in the second guide plate that opens into a space around the first tire or the second tire; The vehicle exterior noise reduction structure according to claim 10.

13. At least one of the first opposing member and the second opposing member includes a fender liner provided to face one of the front wheels or the rear wheels of the vehicle. The vehicle exterior noise reduction structure according to claim 1.

14. The fender liner is a semicircular arc-shaped main body portion provided around the first tire or the second tire; a lower wall portion formed to extend from one end of the main body portion toward the front or rear of the vehicle, The main body portion has the first communication hole or the second communication hole formed therein, The lower wall portion is formed with a fifth communication hole that communicates the enclosed space with an exterior space below the lower wall portion. The vehicle exterior noise reduction structure according to claim 13.

15. a hollow third guide plate provided below the lower wall portion and configured to guide sound from a space around the first tire or the second tire toward the fifth communication hole. The vehicle exterior noise reduction structure according to claim 14.

16. The sound absorbing member further includes a fourth sound absorbing member provided on the third guide plate. The vehicle exterior noise reduction structure according to claim 15.

17. a third cover member having a porous structure, the third cover member being provided at an opening in the third guide plate that opens into a space around the first tire or the second tire; The vehicle exterior noise reduction structure according to claim 15.

18. The first opposing member or the second opposing member includes a bumper seal that is provided to face a rear wheel of the vehicle and closes an opening of a rear side undercover of the vehicle. The vehicle exterior noise reduction structure according to claim 1.

19. a fourth cover member having a porous structure, the fourth cover member being provided at an opening of the first communication hole in the first opposing member or at an opening of the second communication hole in the second opposing member. The vehicle exterior noise reduction structure according to claim 1.

20. The first communicating hole and the second communicating hole are further formed in the space forming member. The vehicle exterior noise reduction structure according to claim 1.

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