Vehicle exterior noise reduction structure

Abstract

To provide a vehicle external noise reduction structure capable of reducing external vehicle noise. [Solution] The vehicle 10's external noise reduction structure 100 comprises reflective members 110, 120, 130, 140 and sound-absorbing members 112, 122, 132, 142. The reflective members 110, 120, 130, 140 are positioned to face either the front or rear direction of the vehicle relative to the wheels 31-34 of the vehicle 10, and reflect the sound radiated from the tires of the wheels 31-34 forward from the front wheels and backward from the rear wheels. The sound-absorbing members 112, 122, 132, 142 absorb at least one of the radiated sound and the reflected sound reflected by the reflective members. This method reduces external noise by separating the sound radiated from the front and rear wheels in the front and rear directions.

Description

[Technical Field]

[0001] This invention relates to a structure for reducing external noise from a vehicle. [Background technology]

[0002] Conventionally, there is a vehicle external noise reduction structure described in Patent Document 1 below. The vehicle external noise reduction structure described in Patent Document 1 comprises a groove-shaped section having a side wall section extending in the longitudinal direction of the vehicle, and a side wall section located on the inside in the vehicle width direction. The side wall section includes a sound-absorbing section made of a sound-absorbing material. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-160677 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The vehicle external noise reduction structure described in Patent Document 1 has room for improvement in terms of its effectiveness in reducing external noise generated by the rolling of tires on the road surface.

[0005] This invention has been made in view of these circumstances, and its purpose is to provide a vehicle external noise reduction structure that can reduce external noise. [Means for solving the problem]

[0006] A vehicle external noise reduction structure that solves the above problems comprises a front wheel reflector and a first sound-absorbing member. The front wheel reflector is provided facing the rearward direction relative to the front wheels of the vehicle and reflects radiated sound generated from the contact surface of the front wheel tires. The first sound-absorbing member absorbs at least one of the radiated sound and the reflected sound reflected by the front wheel reflector.

[0007] Another external noise reduction structure that solves the above problems comprises a rear wheel reflector and a third sound-absorbing member. The rear wheel reflector is provided facing the rear wheel of the vehicle in the direction forward of the vehicle and reflects radiated sound generated from the contact surface of the rear wheel tire. The third sound-absorbing member absorbs at least one of the radiated sound and the reflected sound reflected by the rear wheel reflector.

[0008] With this configuration, radiated sound generated from the tire's contact surface can be reflected forward or backward by the front wheel reflector or rear wheel reflector. Furthermore, the radiated or reflected sound is absorbed by the first or third sound-absorbing member. Therefore, external noise can be reduced. [Effects of the Invention]

[0009] According to the vehicle external noise reduction structure of the present invention, it is possible to reduce external noise. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram illustrating an example of a configuration for measuring external vehicle noise. [Figure 2] A graph showing the relationship between the vehicle's position and the level of external noise. [Figure 3] A side view showing the side structure of the vehicle according to the first embodiment. [Figure 4] A plan view showing the planar structure of the vehicle according to the first embodiment. [Figure 5] A cross-sectional view showing the cross-sectional structure along the VV line in Figure 4. [Figure 6] A cross-sectional view showing the cross-sectional structure along the line VI-VI in Figure 4. [Figure 7] A schematic diagram showing the enlarged structure around the tires of a vehicle. [Figure 8] A graph showing the relationship between the vehicle's position and the external noise level in the first embodiment. [Figure 9] A side view showing the side structure of a vehicle according to a modified example of the first embodiment. [Figure 10] A plan view showing the planar structure of a modified vehicle according to the first embodiment. [Figure 11] Side view showing the side structure of the vehicle according to the second embodiment. [Figure 12] Plan view showing the planar structure of the vehicle according to the second embodiment. [Figure 13] Side view showing the side structure of the vehicle according to the third embodiment. [Figure 14] Plan view showing the planar structure of the vehicle according to the third embodiment. [Figure 15] Cross-sectional view showing the cross-sectional structure along the line XV-XV in FIG. 14. [Figure 16] Side view showing the side structure of the vehicle according to the fourth embodiment. [Figure 17] Plan view showing the planar structure of the vehicle according to the fourth embodiment. [Figure 18] Perspective view showing the perspective structure of the sound absorption box according to the fourth embodiment. [Figure 19] Perspective view showing the perspective structure of the sound absorption box of the modified example according to the fourth embodiment. [Figure 20] Plan view showing the planar structure of the vehicle of the modified example according to the fourth embodiment. [Figure 21] Side view showing the side structure of the vehicle according to the fifth embodiment. [Figure 22] Plan view showing the planar structure of the vehicle according to the fifth embodiment. [Figure 23] Side view showing the side structure of the vehicle of the modified example according to the fifth embodiment. [Figure 24] Plan view showing the planar structure of the vehicle of the modified example according to the fifth embodiment. [Figure 25] Side view showing the side structure of the vehicle according to the sixth embodiment. [Figure 26] Plan view showing the planar structure of the vehicle according to the sixth embodiment. [Figure 27] Side view showing the side structure of the vehicle of the first modified example according to the sixth embodiment. [Figure 28] Plan view showing the planar structure of the vehicle of the first modified example according to the sixth embodiment. [Figure 29] Side view showing the side structure of the vehicle of the second modified example according to the sixth embodiment. [Figure 30] Plan view showing the planar structure of the vehicle of the second modified example according to the sixth embodiment. [Figure 31]A side view showing the side structure of the vehicle according to the seventh embodiment. [Figure 32] A side view showing the side structure of a modified vehicle according to the seventh embodiment. [Modes for carrying out the invention]

[0011] The first to seventh embodiments of the vehicle's external noise reduction structure will be described below with reference to the drawings. To facilitate understanding of the explanation, the same reference numerals will be used for identical components in each drawing whenever possible, and redundant explanations will be omitted.

[0012] <First Embodiment> Before describing the vehicle external noise reduction structure of the first embodiment, the principle of the vehicle external noise reduction structure of the said embodiment will be explained.

[0013] (Explanation of the principle) The inventors of this invention experimentally measured the noise radiated from the front and rear tires of a vehicle by utilizing a so-called indoor pass-by test, which measures vehicle noise indoors. Figures 1 and 2 show the experimental results conducted by the inventors.

[0014] Figure 1 shows the magnitude of external noise radiated from each tire when the right front wheel 31, left front wheel 32, right rear wheel 33, and left rear wheel 34 of vehicle 10 are rotated on a chassis dynamometer, measured by microphone devices M1~M 13 This map shows the external noise levels measured by [the specified method]. In Figure 1, the origin (0,0) is set at position O, which is in front of the vehicle 10. The x-axis represents the axis parallel to the front-rear direction of the vehicle 10, and the y-axis represents the axis parallel to the left-right direction of the vehicle 10. 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.

[0015] As shown in Figure 1, microphone devices M1~M 13They are arranged side by side on the axis m10. The axis m10 is a line parallel to the x-axis and is separated from the center of the vehicle 10 by a predetermined distance L in the y-axis direction. In addition, the distance L is set to 7.5 m by regulations. Also, the microphone devices M1 to M 13 are respectively arranged at the positions shown in FIG. 1. Also, the center positions Pt1 to Pt4 of the wheels 31 to 34 of the vehicle 10 are as shown in FIG. 1.

[0016] In FIG. 1, from the tire of the right front wheel 31 to the microphone devices M1 to M 13 The intensity of the noise at the microphone positions radiated in the direction is represented by vectors Va1 to Va 13 . Each vector Va1 to Va 13 The direction of the arrow indicates the direction of the noise radiated from the tire of the right front wheel 31. Each vector Va1 to Va 13 The length of the arrow indicates the intensity of the noise at the microphone position radiated from the tire of the right front wheel 31. In FIG. 1, similarly, the intensity of the noise radiated from the tire of the left front wheel 32 is represented by vectors Vb1 to Vb 13 , the intensity of the noise radiated from the tire of the right rear wheel 33 is represented by vectors Vc1 to Vc 13 , and the intensity of the noise radiated from the tire of the left rear wheel 34 is represented by vectors Vd1 to Vd 13 . Note that the unit of the noise intensity is [W / m 2 .

[0017] Figure 2 is a graph of the external noise obtained from the experiment shown in Figure 1. In Figure 2, the horizontal axis represents the position on the axis m10 [m], and the vertical axis represents the noise level [dB] of each wheel 31-34, and the relationship between them is shown graphically. In Figure 2, the solid line L1 represents the noise level when all the tires of wheels 31-34 are rotating, the dashed line L2 represents the noise level when only the right front wheel 31 is rotating, and the dashed line L3 represents the noise level when only the left front wheel 32 is rotating. Additionally, the short dashed line L4 represents the noise level when only the right rear wheel 33 is rotating, and the long dashed line L5 represents the noise level when only the left rear wheel 34 is rotating. Hereafter, the noise when all the tires of wheels 31-34 are rotating, as shown by the solid line L1 in Figure 2, will be referred to as "external noise when all tires are running".

[0018] As shown in Figures 1 and 2, the noise intensity [W / m²] at the microphone position radiated from each tire of wheels 31-34 2 The noise level [dB] is distributed in the front-to-rear direction of a microphone device installed on the side of the vehicle 10. For example, as shown by the dashed line L2 in Figure 2, the noise level of the front wheel 31 tires is at its maximum at "+1.3m". Also, as shown by the short dashed line L4 in Figure 2, the noise level of the rear wheel 33 tires is at its maximum at "+6.0m". Furthermore, as shown by the solid line L1 in Figure 2, the noise level of external noise when all tires are running is at its maximum at "+3~5m".

[0019] As shown in Figures 1 and 2, when the microphone position where the noise intensity radiated from the front wheels 31 and 32 is maximum is close to the microphone position where the noise intensity radiated from the rear wheels 33 and 34 is maximum, these four noises may reinforce each other, which is considered to be a factor that increases the external noise level when all tires are in use. Therefore, if the noise radiated from the front wheels 31 and 32 and the noise radiated from the rear wheels 33 and 34 can be separated by distance, the external noise when all tires are in use can be reduced.

[0020] The following describes the first embodiment of the external noise reduction structure, which is constructed based on this principle.

[0021] (Configuration of the vehicle and external noise reduction structure) Figure 3 is a side view showing the left side structure of the vehicle 10 according to the first embodiment. Figure 4 is a plan view showing the top structure of the vehicle 10 according to the first embodiment. In the following, the front direction of the vehicle is indicated by the symbol FR, the rear direction by the symbol BA, the right direction by the symbol RH, and the left direction by the symbol LH. The longitudinal direction of the vehicle is indicated by the symbol FB, and the left-right direction of the vehicle is indicated by the symbol RL.

[0022] As shown in Figures 3 and 4, the vehicle 10 comprises a vehicle body 20 and wheels 31-34. The wheels 31-34 are connected to axles (not shown) and are rotatably supported relative to the vehicle body 20 via these axles.

[0023] The external noise reduction structure 100 of the vehicle 10 in this embodiment includes reflective members 110 and 120 for the front wheels and reflective members 130 and 140 for the rear wheels.

[0024] The front wheel reflector 110 is provided on the bottom surface of the vehicle body 20 in the area corresponding to BA in the rear direction of the right front wheel 31. Figure 5 shows the cross-sectional structure along the line VV in Figure 4. Figure 6 shows the cross-sectional structure along the line VI-VI in Figure 4. As shown in Figures 3 to 6, the front wheel reflector 110 comprises a main body member 111 and a sound-absorbing member 112.

[0025] The main body member 111 is made of a material capable of reflecting noise generated from the right front wheel 31, such as resin. Furthermore, the front wheel reflector member 110 is more effective if it is made of a material that has sound absorption properties in addition to sound reflection properties. As a material with both reflective and sound absorption properties, for example, glass fiber nonwoven fabric can be used. As a glass fiber nonwoven fabric, for example, Sekiso's product name "Sekiso Acoustic Board (SAB)", which is a sound-absorbing board material made by blending glass fibers with olefin fibers as a binder, can be used. As shown in Figures 3 and 4, the main body member 111 may also include an opposing part 111a and a hanging wall part 111b to further enhance the effect.

[0026] The opposing portion 111a is the part of the main body member 111 that is positioned opposite the tire of the right front wheel 31 in the rear direction BA of the vehicle. The opposing portion 111a is formed to extend parallel to the left-right direction RL of the vehicle. As shown in Figure 5, the cross-sectional shape of the opposing portion 111a perpendicular to the left-right direction RL of the vehicle is V-shaped. The opposing portion 111a has an opening that opens toward the contact surface of the tire of the right front wheel 31.

[0027] The hanging wall portion 111b is a part of the main body member 111 that is formed to be bent from the end of the opposing portion 111a in the vehicle left direction LH toward the vehicle front direction FR. As shown in Figure 6, the cross-sectional structure of the hanging wall portion 111b is V-shaped, similar to that of the opposing portion 111a. The hanging wall portion 111b has an opening that opens toward the left side of the tire of the right front wheel 31.

[0028] Furthermore, the rear wheel reflective member 130 may also function as a spats capable of reducing air resistance flowing into the tire of the right rear wheel 33.

[0029] As shown in Figures 5 and 6, the sound-absorbing member 112 is provided inside the opposing portion 111a and the hanging wall portion 111b of the main body member 111. The sound-absorbing member 112 can be made of a material capable of absorbing noise generated from the tire contact surface of the right front wheel 31, such as a material made of polyester fiber. As the polyester fiber, the product name "Sekiso Acoustic Fiber (SAF)" manufactured by Sekiso Corporation can be used.

[0030] As shown in Figures 3 and 4, the front wheel reflector 120 is provided on the bottom surface of the vehicle body 20 in the area corresponding to the rearward direction BA of the left front wheel 32. The front wheel reflector 120 comprises a main body member 121 and a sound-absorbing member 122. The main body member 121 comprises an opposing portion 121a positioned opposite the tire contact surface of the left front wheel 32 in the rearward direction BA, and a hanging wall portion 121b formed to be bent from the end of the opposing portion 121a in the rightward direction RH toward the front direction FR. The configurations of the main body member 121 and the sound-absorbing member 122 are the same as or similar to the configurations of the main body member 111 and the sound-absorbing member 112 of the front wheel reflector 110, so a description of their configurations will be omitted.

[0031] The rear wheel reflective member 130 is provided on the bottom surface of the vehicle body 20 in the portion corresponding to the front FR of the right rear wheel 33. The rear wheel reflective member 130 comprises a main body member 131 and a sound-absorbing member 132. The main body member 131 comprises an opposing portion 131a positioned opposite the tire of the right rear wheel 33 in the front FR of the vehicle, and a hanging wall portion 131b formed to be bent from the end of the opposing portion 131a in the left LH direction towards the rear BA direction of the vehicle. The configurations of the main body member 131 and the sound-absorbing member 132 are the same as or similar to the configurations of the main body member 111 and the sound-absorbing member 112 of the front wheel reflective member 110, so a description of their configurations will be omitted.

[0032] A rear wheel reflective member 140 is provided on the bottom surface of the vehicle body 20 in the portion corresponding to the front direction (FR) of the left rear wheel 34. The rear wheel reflective member 140 comprises a main body member 141 and a sound-absorbing member 142. The main body member 141 comprises an opposing portion 141a positioned opposite the tire of the left rear wheel 34 in the front direction (FR), and a hanging wall portion 141b formed to be bent from the end of the opposing portion 141a in the right direction (RH) toward the rear direction (BA). The configurations of the main body member 141 and the sound-absorbing member 142 are the same as or similar to the configurations of the main body member 111 and the sound-absorbing member 112 of the front wheel reflective member 110, so a description of their configurations is omitted.

[0033] (Operation and effects of the external noise reduction structure of the first embodiment) As shown in Figure 7, when the tire 200 rolls, pattern noise of 1kHz to 2kHz is generated from both the front and rear of the contact point 230 between the tire 200 and the ground 210, forming the external noise. In the case of a tire alone, the tire noise spreads from the contact point 230 in the longitudinal direction FB of the vehicle, and then spreads in the lateral direction RL of the vehicle as it moves away from the contact surface. When the tire 200 is mounted on a vehicle together with a wheel, the tire noise basically spreads in the same way as when it is alone, initially in the longitudinal direction, and then in a gourd-shaped spread at a 45° angle. However, the tire noise may spread differently depending on the vehicle body and accessories.

[0034] Therefore, the external noise reduction structure 100 of the vehicle 10 in this embodiment comprises reflective members 110, 120, 130, 140 and sound-absorbing members 112, 122, 132, 142, as described above. The reflective members 110, 120, 130, 140 are provided so as to face either the vehicle forward direction FR or the vehicle rear direction BA relative to the wheels 31-34, and reflect the sound radiated from the tires of the wheels 31-34. The sound-absorbing members 112, 122, 132, 142 are provided inside the reflective members 110, 120, 130, 140, and absorb the radiated sound. In this embodiment, the sound-absorbing members 112, 122 are an example of first sound-absorbing members, and the sound-absorbing members 132, 142 are an example of third sound-absorbing members.

[0035] In the external noise reduction structure 100 of this embodiment, as shown by the dashed arrow n11 in Figure 4, noise generated from the tire of the right front wheel 31 is reflected by the front wheel reflector 110 located in the rear direction BA of the vehicle of the right front wheel 31 and concentrated in the front direction FR of the vehicle. In addition, a portion of the noise generated from the tire of the right front wheel 31 is absorbed by the sound-absorbing member 112 provided on the front wheel reflector 110. Similarly, noise generated from the tire of the left front wheel 32 can also be concentrated in the front direction FR of the vehicle by the front wheel reflector 120 and absorbed by the sound-absorbing member 122, as shown by the dashed arrow n12 in Figures 3 and 4.

[0036] Furthermore, the noise generated from the right rear wheel 33 is reflected by the rear wheel reflector 130 located in the front direction FR of the vehicle on the right rear wheel 33, as shown by the dashed arrow n13 in Figure 4, and concentrated in the rear direction BA of the vehicle. In addition, a portion of the noise generated from the right rear wheel 33 is absorbed by the sound-absorbing member 132 provided on the rear wheel reflector 130. Similarly, the noise generated from the left rear wheel 34 can also be concentrated in the rear direction BA of the vehicle by the rear wheel reflector 130 and absorbed by the sound-absorbing member 142.

[0037] As described above, the tire noise from the front wheels 31 and 32 diffuses forward (FR) of the vehicle, and the tire noise from the rear wheels 33 and 34 diffuses backward (BA) of the vehicle. As a result, the position where the tire noise from the front wheels 31 and 32 is maximum shifts forward (FR), and the position where the tire noise from the rear wheels 33 and 34 is maximum shifts backward (BA) of the vehicle. In other words, the position where the tire noise from the front wheels 31 and 32 is maximum and the position where the tire noise from the rear wheels 33 and 34 is maximum can be separated, and as a result, external noise during four-wheel driving can be reduced.

[0038] Figure 8 shows the results of experimental measurements of the external noise of a vehicle 10 equipped with the external noise reduction structure 100 of this embodiment. In Figure 8, the experimental results when all of the front wheel reflective members 110, 120 and rear wheel reflective members 130, 140 are installed on the vehicle 10 are shown by the solid line L10, the experimental results when only the front wheel reflective members 110, 120 are installed on the vehicle 10 are shown by the dashed line L11, and the experimental results when only the rear wheel reflective members 130, 140 are installed on the vehicle 10 are shown by the double dashed line L12.

[0039] As shown by the solid line L10 in Figure 8, when all of the front wheel reflective members 110, 120 and rear wheel reflective members 130, 140 are provided on the vehicle 10 as in the external noise reduction structure 100 of this embodiment, the external noise level can be suppressed to 69 dB or less. Therefore, compared to the reference example vehicle 10 shown in Figure 2, it is possible to reduce external noise by about 2 dB.

[0040] Furthermore, as shown by the dashed-dotted lines L11 and L12 in Figure 8, even when only the front wheel reflective members 110 and 120 are installed on the vehicle 10, or when only the rear wheel reflective members 130 and 140 are installed on the vehicle 10, the external noise level can be kept below 70 dB, and external noise can be reduced by about 1 dB. This is because, for example, even when only the front wheel reflective members 110 and 120 are installed on the vehicle 10, the position where the tire noise of the front wheels 31 and 32 is maximum can be shifted forward FR of the vehicle, thereby separating the position where the tire noise of the front wheels 31 and 32 is maximum from the position where the tire noise of the rear wheels 33 and 34 is maximum. The same applies when only the rear wheel reflective members 130 and 140 are installed on the vehicle 10.

[0041] Furthermore, the front wheel reflective members 110 and 120 include opposing portions 111a and 121a provided opposite to the front wheels 31 and 32 in the rear direction BA of the vehicle, and hanging wall portions 111b and 121b formed to extend from the opposing portions 111a and 121a in the front direction FR of the vehicle along the respective sides of the front wheels 31 and 32. In this embodiment, the opposing portions 111a and 121a are examples of first opposing portions, and the hanging wall portions 111b and 121b are examples of first hanging wall portions. Furthermore, the rear wheel reflective members 130 and 140 include opposing portions 131a and 141a provided opposite to the rear wheels 33 and 34 in the front direction FR of the vehicle, and hanging wall portions 131b and 141b formed to extend from the opposing portions 131a and 141a in the rear direction BA of the vehicle along the respective sides of the rear wheels 33 and 34. In this embodiment, the opposing portions 131a and 141a are examples of second opposing portions, and the hanging wall portions 131b and 141b are examples of second hanging wall portions.

[0042] With this configuration, the sound radiated from each of the front tires 31 and 32 can be more effectively reflected forward (FR) by the front wheel reflectors 110 and 120, and the sound radiated from each of the rear tires 33 and 34 can be more effectively reflected backward (BA) by the rear wheel reflectors 130 and 140. Therefore, it is possible to reduce the noise level outside the vehicle more accurately. However, with the reflectors (110, etc.) alone, the noise on the receiving end will increase because they simply reflect the tire noise. If sound-absorbing material (112, etc.) is placed inside the reflectors, the noise can be gently pushed back, and the effect of reversing the noise without increasing the sound on the opposite side.

[0043] (modified version) Next, a modified example of the external noise reduction structure 100 of the first embodiment will be described.

[0044] The modified external noise reduction structure 100, as shown in Figures 9 and 10, differs from the external noise reduction structure 100 of the above embodiment in that it is equipped only with front wheel reflective members 110 and 120 and does not have rear wheel reflective members 130 and 140. The front wheel reflective member 110 is fixed to the lower part of the fender liner of the right front wheel 31 of the vehicle 10, in the portion corresponding to the rearward direction BA of the tire. The front wheel reflective member 120 is fixed to the lower part of the fender liner of the left front wheel 32, in the portion corresponding to the rearward direction BA of the tire. The front wheel reflective members 110 and 120 are, for example, mudguards and are formed from a plate-shaped material capable of reflecting and absorbing sound radiated from the tires of the front wheels 31 and 32. As such a material, for example, a combination of glass fiber nonwoven fabric such as SAB and polyester fiber such as SAF can be used.

[0045] Even with this configuration, the position where the tire noise of the front wheels 31 and 32 is greatest can be shifted forward (FR) of the vehicle, making it possible to reduce the noise level outside the vehicle.

[0046] <Second Embodiment> Next, the external noise reduction structure 100 of the vehicle 10 according to the second embodiment will be described. The following description will focus on the differences from the external noise reduction structure 100 of the above embodiment.

[0047] (Configuration of the external noise reduction structure) As shown in Figures 11 and 12, the external noise reduction structure 100 of this embodiment is provided on the fender liners 41 to 44, respectively.

[0048] The left front fender liner 42 is composed of a reflective member 420 and a sound-absorbing member 421.

[0049] The reflective member 420 is provided in the fender liner 42 in the portion corresponding to the rearward direction BA of the left front wheel 32. The reflective member 420 is made of a material capable of softly reflecting the sound radiated from the tire contact surface of the left front wheel 32 while absorbing it, such as a glass fiber nonwoven fabric such as SAB.

[0050] The sound-absorbing member 421 is provided in the fender liner 42 above the left front wheel 32 and in the front FR portion of the vehicle. The sound-absorbing member 421 is made of a material capable of absorbing reflected sound reflected by the reflecting member 420, such as polyester fiber such as SAF.

[0051] The right front fender liner 41 is similarly composed of a reflective member 410 and a sound-absorbing member 411. Since the configurations of the reflective member 410 and the sound-absorbing member 411 are the same as or similar to those of the reflective member 420 and sound-absorbing member 421 of the left front fender liner 42, a detailed explanation of them will be omitted.

[0052] The left rear fender liner 44 is composed of a reflective member 440 and a sound-absorbing member 441. The reflective member 440 is provided on the fender liner 44 in the FR direction relative to the left rear wheel 34. The sound-absorbing member 441 is provided on the fender liner 44 above the left rear wheel 34 and in the BA direction relative to the rear of the vehicle. The materials of the reflective member 440 and the sound-absorbing member 441 can be the same as or similar to the materials of the reflective member 420 and sound-absorbing member 421 of the left front fender liner 42.

[0053] The right rear fender liner 43 is similarly composed of a reflective member 430 and a sound-absorbing member 431. Since the configurations of the reflective member 430 and the sound-absorbing member 431 are identical or similar to those of the reflective member 440 and the sound-absorbing member 441 of the left rear fender liner 44, a detailed explanation of them will be omitted.

[0054] (Operation and effects of the external noise reduction structure of the second embodiment) As described above, the external noise reduction structure 100 of the vehicle 10 in this embodiment comprises reflective members 410, 420, 430, and 440, and sound-absorbing members 411, 421, 431, and 441. The reflective members 410 and 420 are provided in the rear direction BA of the vehicle so as to face the front wheels 31 and 32, and the reflective members 430 and 440 are provided in the front direction FR of the vehicle so as to face the rear wheels 33 and 34, reflecting the sound radiated from the tires of the wheels 31 to 34 in the front and rear directions, respectively. The sound-absorbing members 411, 421, 431, and 441 are provided on the opposite side of the reflective members 410, 420, 430, and 440, and absorb the reflected sound. The sound-absorbing members 411 and 421 are examples of first sound-absorbing members, and the sound-absorbing members 431 and 441 are examples of third sound-absorbing members.

[0055] Even with this configuration, it is possible to achieve the same or similar functions and effects as the external noise reduction structure 100 of the first embodiment.

[0056] <Third Embodiment> Next, the external noise reduction structure 100 of the vehicle 10 according to the third embodiment will be described. The following description will focus on the differences from the external noise reduction structure 100 of each of the above embodiments.

[0057] (Configuration of the external noise reduction structure) As shown in Figures 13 and 14, the vehicle body 20 is provided with openings OR and OL on its right and left sides, respectively, to serve as entry and exit points. The vehicle body 20 is equipped with a pair of left and right rocker sections 21 and 22 that extend along the lower edges of the openings OR and OL in the longitudinal direction FB of the vehicle. The rocker section 21 reinforces the lower part of the opening OR while being joined to the floor panel, and the rocker section 22 reinforces the lower part of the opening OL while being joined to the floor panel.

[0058] Figure 15 is a cross-sectional view showing the cross-sectional structure along the line XV-XV in Figure 14. As shown in Figure 15, the external noise reduction structure 100 of this embodiment includes a sound-absorbing member 150 positioned adjacent to the lower surface of the rocker section 21. The cross-sectional shape of the sound-absorbing member 150 perpendicular to the vehicle longitudinal direction FB is close to concave. As shown in Figures 13 and 14, the sound-absorbing member 150 is formed to extend along the lower surface of the rocker section 21 in the vehicle longitudinal direction FB. The sound-absorbing member 150 is made of a material capable of absorbing noise radiated from each of the tires of the wheels 31 to 34, such as a sound-absorbing plate material such as SAB + SAF + polyester fiber.

[0059] The external noise reduction structure 100 further includes a sound-absorbing member 160 positioned adjacent to the lower surface of the rocker section 22. The structure of the sound-absorbing member 160 is the same as or similar to that of the sound-absorbing member 150, so its description is omitted.

[0060] (Operation and effects of the external noise reduction structure of the third embodiment) As described above, the external noise reduction structure 100 of the vehicle 10 in this embodiment includes sound-absorbing members 150 and 160 provided adjacent to the lower surfaces of the rocker sections 21 and 22 of the vehicle. The sound-absorbing member 150 absorbs sound radiated from the right front wheel 31 in the rear direction BA of the vehicle, and sound radiated from the right rear wheel 33 in the front direction FR of the vehicle. The sound-absorbing member 160 absorbs sound radiated from the left front wheel 32 in the rear direction BA of the vehicle, and sound radiated from the left rear wheel 34 in the front direction FR of the vehicle. In this embodiment, the sound-absorbing members 150 and 160 are examples of fifth sound-absorbing members.

[0061] With this configuration, the sound radiated from the wheels 31-34 can be absorbed by the sound-absorbing members 150 and 160, reducing noise behind the front wheels and in front of the rear wheels. By separating the main directions of noise from the front and rear wheels, it is possible to further reduce the external noise level.

[0062] <Fourth Embodiment> Next, the external noise reduction structure 100 of the vehicle 10 according to the fourth embodiment will be described. The following description will focus on the differences from the external noise reduction structure 100 of each of the above embodiments.

[0063] (Configuration of the external noise reduction structure) As shown in Figures 16 and 17, the external noise reduction structure 100 of this embodiment includes sound-absorbing boxes 170 and 180. In this embodiment, sound-absorbing box 170 is an example of a second sound-absorbing member, and sound-absorbing box 180 is an example of a fourth sound-absorbing member.

[0064] The sound-absorbing box 170 is located in front of the front wheels, below the center of the front end of the vehicle 10. As shown in Figure 18, the sound-absorbing box 170 is a cylindrical body formed to extend in the left-right direction RL of the vehicle. The sound-absorbing box 170 has an opening 171 in its center. As shown in Figure 17, the opening 171 is located on the vehicle body centerline m20. The opening 171 is formed to open toward the front wheels in the rearward direction BA of the vehicle.

[0065] As shown in Figures 16 and 17, the sound-absorbing box 180 is located behind the rear wheels, in a position below the center of the rear end of the vehicle 10. The sound-absorbing box 180 has the same or similar structure as the sound-absorbing box 170. However, the opening 181 of the sound-absorbing box 180 is formed to open toward the rear wheels in the forward direction of the vehicle (FR).

[0066] Furthermore, the interiors of the sound-absorbing boxes 170 and 180 may be filled with internal sound-absorbing materials such as sound-absorbing foam (SAF) that are capable of absorbing noise.

[0067] (Operation and effects of the external noise reduction structure of the fourth embodiment) In the external noise reduction structure 100 of the vehicle 10 of this embodiment, as shown by arrows n21 and n22 in Figure 17, reflected sound from the rearward BA portion of the front wheels 31 and 32 is collected inside the sound-absorbing box 170 through the opening 171, thereby absorbing or canceling the sound. Similarly, as shown by arrows n23 and n24 in Figure 17, reflected sound from the forward FR portion of the rear wheels 33 and 34 is collected inside the sound-absorbing box 180 through the opening 181, thereby absorbing or canceling the sound. This suppresses the diffusion of reflected sound outside the vehicle, making it possible to reduce the external noise level more effectively.

[0068] (modified version) Next, a modified example of the vehicle exterior noise reduction structure 100 of the fourth embodiment will be described.

[0069] In this modified example, as shown in Figure 19, openings 172 and 173 are formed in the sound-absorbing box 170. As shown in Figure 20, the openings 172 and 173 open toward the right front wheel 31 and the left front wheel 32, respectively.

[0070] Similarly, as shown in Figure 20, the sound-absorbing box 180 has openings 182 and 183. The openings 182 and 183 open toward the right rear wheel 33 and the left rear wheel 34, respectively.

[0071] With this configuration, as shown by arrows n25 and n26 in Figure 20, the sound radiated from each of the front wheels 31 and 32 toward the front of the vehicle (FR) is collected inside the sound-absorbing box 170 through openings 172 and 173, thereby absorbing or canceling the sound. Similarly, as shown by arrows n27 and n28 in Figure 20, the sound radiated from each of the rear wheels 33 and 34 toward the rear of the vehicle (BA) is collected inside the sound-absorbing box 180 through openings 182 and 183, thereby absorbing or canceling the sound. This suppresses the diffusion of radiated sound outside the vehicle, making it possible to more effectively reduce the external noise level.

[0072] <Fifth Embodiment> Next, the external noise reduction structure 100 of the vehicle 10 according to the fifth embodiment will be described. The following description will focus on the differences from the external noise reduction structure 100 of each of the above embodiments.

[0073] (Configuration of the external noise reduction structure) As shown in Figures 21 and 22, the external noise reduction structure 100 of this embodiment includes front wheel rectifier structures 310, 320 and rear wheel rectifier structures 330, 340.

[0074] The front wheel aerodynamic structure 320 is provided on the bottom surface of the vehicle body 20 in front of the left front wheel 32. The front wheel aerodynamic structure 320 is made of a sound-absorbing material, such as SAB+SAF, plus polyester fibers, that can absorb noise radiated from the left front wheel 32 in the front direction (FR). The front wheel aerodynamic structure 310 and the rear wheel aerodynamic structures 330 and 340 have the same or similar shape as the front wheel aerodynamic structure 320.

[0075] (Operation and effects of the external noise reduction structure of the fifth embodiment) In the external noise reduction structure 100 of this embodiment, the front wheel airflow rectifiers 310 and 320 are formed of sound-absorbing material, which allows for a wider passage for sound radiated from the front wheels 31 and 32 compared to a case where the front wheel airflow rectifiers 310 and 320 are not provided. This makes it easier for sound radiated from the front wheels 31 and 32 to diffuse forward (FR) through the front wheel airflow rectifiers 310 and 320. Similarly, the rear wheel airflow rectifiers 330 and 340 are formed of sound-absorbing material, which makes it easier for sound radiated from the rear wheels 33 and 34 to diffuse backward (BA) through the rear wheel airflow rectifiers 330 and 340. This makes it possible to reduce noise, for example, inside the wheel wells, and because the spread of tire noise from the front and rear wheels is separated front to rear, it is possible to reduce external noise more effectively.

[0076] (modified version) Next, a modified example of the vehicle noise reduction structure 100 of the fifth embodiment will be described.

[0077] In this modified external noise reduction structure 100, as shown in Figures 23 and 24, the front wheel airflow rectifier structure 320 is formed in a mesh or grid pattern on the FR side of the left front fender liner and on the bottom surface of the vehicle body 20 in front of the left front wheel 32. The front wheel airflow rectifier structure 310 has the same or a similar shape.

[0078] The rear wheel airflow rectifier structure 340 is configured such that the portion of the rear bumper 45 of the vehicle 10 corresponding to the rearward direction BA of the left rear wheel 34 is formed in a mesh or grid pattern. The rear wheel airflow rectifier structure 330 has the same or a similar shape.

[0079] With this configuration, the sound radiated from the front wheels 31 and 32 is more easily diffused forward (FR) through the front wheel airflow rectifiers 310 and 320 and the vehicle's front grille. Similarly, the sound radiated from the rear wheels 33 and 34 is more easily diffused backward (BA) through the rear wheel airflow rectifiers 330 and 340. This makes it possible to reduce noise, for example, inside the wheel wells, and because the spread of tire noise from the front and rear wheels is separated front to rear, it is possible to reduce external noise more effectively.

[0080] <Sixth Embodiment> Next, the external noise reduction structure 100 of the vehicle 10 according to the sixth embodiment will be described. The following description will focus on the differences from the external noise reduction structure 100 of each of the above embodiments.

[0081] (Configuration of the external noise reduction structure) As shown in Figures 25 and 26, the external noise reduction structure 100 of this embodiment includes sound-absorbing members 710, 720, 730, and 740 that are attached to the wheels 31 to 34, respectively.

[0082] The sound-absorbing member 720 is used as a wheel cap for the left front wheel 32. The sound-absorbing member 720 is made of a material capable of absorbing sound, such as glass fiber impregnated sound-absorbing board material such as SAB, polyester fiber such as SAF, or a combination thereof. The sound-absorbing members 710, 730, and 740 are made of the same or similar material as the sound-absorbing member 720 and are used as wheel caps for the right front wheel 31, the right rear wheel 33, and the left rear wheel 34, respectively. In this embodiment, the sound-absorbing members 710, 720, 730, and 740 are examples of the sixth sound-absorbing members.

[0083] (Operation and effects of the external noise reduction structure of the sixth embodiment) In the external noise reduction structure 100 of this embodiment, for example, reflected sound reflected from the BA side portion of the wheel well of the left front wheel 32, and tire radiated sound flowing into the wheel well are absorbed by the sound-absorbing member 720, thereby reducing the sound pressure inside the wheel well of the left front wheel 32. Similarly, the sound pressure inside the wheel wells of the right front wheel 31, the right rear wheel 33, and the left rear wheel 34 can also be reduced, thereby enabling a more precise reduction of external noise.

[0084] (First variation) Next, a first modified example of the vehicle exterior noise reduction structure 100 of the sixth embodiment will be described.

[0085] In this modified example of the external noise reduction structure 100, as shown in Figures 27 and 28, a sound-absorbing member 720 is provided on the tire side of the inner panel 52 on the right-hand (RH) side of the wheel well of the left front wheel 32. Similarly, a sound-absorbing member 710 is provided on the tire side of the inner panel 51 on the left-hand (LH) side of the wheel well of the right front wheel 31. Furthermore, a sound-absorbing member 730 is provided on the tire side of the inner panel 53 on the left-hand (LH) side of the wheel well of the right rear wheel 33. In addition, a sound-absorbing member 740 is provided on the tire side of the inner panel 54 on the right-hand (RH) side of the wheel well of the left rear wheel 34.

[0086] Even with this configuration, it is possible to obtain the same or similar functions and effects as the external noise reduction structure 100 of the sixth embodiment.

[0087] (Second variation) Next, a second modified example of the vehicle exterior noise reduction structure 100 of the sixth embodiment will be described.

[0088] In this modified external noise reduction structure 100, as shown in Figures 29 and 30, sound-absorbing members 710, 720, 730, and 740 are provided on the inside of the tire wheels of the wheels 31 to 34, respectively.

[0089] Even with this configuration, it is possible to obtain the same or similar functions and effects as the external noise reduction structure 100 of the sixth embodiment.

[0090] <Seventh Embodiment> Next, the external noise reduction structure 100 of the vehicle 10 according to the seventh embodiment will be described. The following description will focus on the differences from the external noise reduction structure 100 of each of the above embodiments.

[0091] (Configuration of the external noise reduction structure) As shown in Figure 31, the external noise reduction structure 100 of this embodiment includes scooping members 520, 540 and sound-absorbing boxes 620, 640.

[0092] The scooping member 520 is formed to protrude from the bottom surface of the vehicle body 20 toward the ground 210 in the vehicle rear direction BA of the left front wheel 32. The scooping member 520 is made of a material capable of guiding the sound radiated from the tire of the left front wheel 32 toward the vehicle rear direction BA to the sound absorbing box 620, such as a glass fiber impregnated sound absorbing board material such as SAB.

[0093] The sound-absorbing box 620 is located on the left front fender liner 42 in the rearward direction BA of the vehicle and is positioned above the scooping member 520. The left front fender liner 42 is provided with a perforated structure 42a for connecting the wheel well of the left front wheel 32 to the sound-absorbing box 620. The sound-absorbing box 620 may contain a material capable of absorbing the radiated sound guided by the scooping member 520, such as polyester fibers like SAF.

[0094] Similarly, a scooping member 510 and a sound-absorbing box 610 are also provided on the right front wheel 31 of the vehicle 10.

[0095] The scooping member 540 is formed to protrude from the bottom surface of the vehicle body 20 toward the ground 210 in the vehicle forward direction (FR) of the left rear wheel 34. The scooping member 540 is also made of a glass fiber impregnated sound-absorbing board material such as SAB. The sound-absorbing box 640 is provided in the vehicle forward direction (FR) of the left rear fender liner 44 and in the portion above the scooping member 540. The left rear fender liner 44 is provided with a perforated structure (not shown) to connect the wheel well of the left rear wheel 34 and the sound-absorbing box 640.

[0096] Similarly, a scooping member 530 and a sound-absorbing box 630 are also provided on the right rear wheel 33 of the vehicle 10.

[0097] (Operation and effects of the external noise reduction structure of the 7th embodiment) In the external noise reduction structure 100 of this embodiment, for example, as shown by arrow n42 in Figure 31, sound radiated from the left front wheel 32 in the rear direction BA of the vehicle is collected along the scooping member 520 and absorbed by the sound absorbing box 620. Similarly, sound radiated from the left rear wheel 34 in the front direction FR of the vehicle is collected along the scooping member 540 and absorbed by the sound absorbing box 640. In this way, the external noise reduction structure 100 of this embodiment can efficiently absorb sound radiated from each wheel 31 to 34, making it possible to reduce the external noise level more accurately.

[0098] (modified version) Next, a modified example of the external noise reduction structure 100 of the seventh embodiment will be described.

[0099] In this embodiment, as shown in Figure 32, the scooping member 520 may have the same or a similar shape as a spats that can reduce the resistance of air flowing into the tire of the left front wheel 32. Although not shown in the figures, the same or a similar structure is also provided for the right front wheel 31, the right rear wheel 33, and the left rear wheel 34.

[0100] Even with this configuration, the same or similar functions and effects as those of the external noise reduction structure 100 of the seventh embodiment can be obtained.

[0101] <Other Embodiments> This disclosure is not limited to the specific examples given above.

[0102] For example, the configurations of the external noise reduction structure 100 in each embodiment and modified example can be used in combination with each other.

[0103] The shape, material, and other properties of each element constituting the external noise reduction structure 100 can be changed as appropriate.

[0104] To further reduce the noise emitted from the tires of each wheel 31-34, wheel skirts may be provided on each wheel 31-34.

[0105] Even the above-mentioned examples, with appropriate design modifications by those skilled in the art, are included within the scope of this disclosure, as long as they possess the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the above-mentioned examples are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-mentioned examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise. [Explanation of Symbols]

[0106] 10: Vehicle, 20: Vehicle body, 21, 22: Rocker section, 31-34: Wheels, 100: External noise reduction structure, 110, 120: Reflective members for front wheels, 111a, 121a: Opposing section (first opposing section), 111b, 121b: Hanging wall section (first hanging wall section), 112, 122, 411, 421: Sound absorbing member (first sound absorbing member), 132, 142, 431, 441: Sound absorbing member (third sound absorbing member), 620, 640: Sound absorbing box, 130, 14 0: Reflective member for rear wheel, 131a, 141a: Second opposing part, 131b, 141b: Second hanging wall part, 150, 160: Fifth sound-absorbing member, 170: Sound-absorbing box (second sound-absorbing member), 180: Sound-absorbing box (fourth sound-absorbing member), 410, 420: Reflective member (reflective member for front wheel), 430, 440: Reflective member (reflective member for rear wheel), 520, 540: Scoop-up member, 710, 720, 730, 740: Sound-absorbing member (sixth sound-absorbing member).

Claims

1. A front wheel reflector is provided facing the rear of the vehicle relative to the front wheel, and reflects sound radiated from the contact surface of the front wheel tire. The system includes a first sound-absorbing member that absorbs at least one of the radiated sound and the reflected sound reflected by the front wheel reflector. Vehicle external noise reduction structure.

2. The first sound-absorbing member is provided inside the front wheel reflector and absorbs the radiated sound and the reflected sound. The vehicle external noise reduction structure according to claim 1.

3. The first sound-absorbing member is provided facing the front wheels of the vehicle in the forward direction of the vehicle and absorbs the reflected sound reflected by the front wheel reflector. The vehicle external noise reduction structure according to claim 1.

4. The aforementioned reflective member for the front wheel is A first opposing portion is provided in the rear direction of the vehicle, facing the front wheels of the vehicle, It comprises a first hanging wall portion formed to extend from the first opposing portion in the direction of the vehicle forward along the side of the front wheel. The vehicle external noise reduction structure according to claim 1.

5. The vehicle further comprises a second sound-absorbing member located below the center of the front end of the vehicle, which absorbs the reflected sound reflected by the front wheel reflector. The vehicle external noise reduction structure according to claim 1.

6. The second sound-absorbing member is a cylindrical member that extends in the left-right direction of the vehicle and has an opening on the centerline of the vehicle body that opens toward the rear of the vehicle. The vehicle external noise reduction structure according to claim 5.

7. The second sound-absorbing member is a cylindrical member that extends in the left-right direction of the vehicle and has an opening that opens toward the front wheels of the vehicle. The vehicle external noise reduction structure according to claim 5.

8. A rear wheel reflector is provided facing the rear wheel of the vehicle in the forward direction and reflects sound radiated from the contact surface of the rear wheel tire, The system includes a third sound-absorbing member that absorbs at least one of the radiated sound and the reflected sound reflected by the rear wheel reflector. Vehicle external noise reduction structure.

9. The third sound-absorbing member is provided inside the rear wheel reflector and absorbs the reflected sound. The vehicle external noise reduction structure according to claim 8.

10. The third sound-absorbing member is provided in the rear direction of the vehicle, facing the rear wheels of the vehicle, and absorbs the reflected sound reflected by the rear wheel reflector. The vehicle external noise reduction structure according to claim 8.

11. The aforementioned rear wheel reflective member is A second opposing portion is provided in the forward direction of the vehicle, facing the rear wheels of the vehicle, It comprises a second hanging wall portion formed to extend from the second opposing portion in the direction of the rear of the vehicle along the side of the rear wheel. The vehicle external noise reduction structure according to claim 8.

12. The vehicle further comprises a fourth sound-absorbing member located below the center of the rear end, which absorbs the reflected sound reflected by the rear wheel reflector. The vehicle external noise reduction structure according to claim 8.

13. The fourth sound-absorbing member is a cylindrical member that extends in the left-right direction of the vehicle and has an opening that opens toward the front of the vehicle at a portion of the vehicle's centerline. The vehicle external noise reduction structure according to claim 12.

14. The fourth sound-absorbing member is a cylindrical member that extends in the left-right direction of the vehicle and has an opening that opens toward the rear wheels of the vehicle. The vehicle external noise reduction structure according to claim 12.

15. The vehicle further comprises a fifth sound-absorbing member provided adjacent to the lower surface of a rocker section that reinforces the lower edge of the entrance / exit door located on the side of the vehicle, and which absorbs the radiated sound. The vehicle external noise reduction structure according to claim 1 or 8.

16. The vehicle further comprises a sixth sound-absorbing member provided on the front or rear wheel of the vehicle. The vehicle external noise reduction structure according to claim 1 or 8.

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