Vehicle front structure

Abstract

The present disclosure obtains a vehicle front structure capable of suppressing intrusion of noise into a cabin. A vehicle front structure (10) is provided with: a cabin front wall panel lower member (22) which is integrally molded by casting with a frame section of a vehicle front and which has ribs (26) on the inside of a cabin; a sound insulation member (60) disposed along the rib (26); a compartment front wall muffler (40) disposed adjacent to the vehicle upper side of the sound insulation member (60); a floor muffler (50) disposed adjacent to the vehicle rear side of the sound insulation member (60); and a pad member (70) disposed adjacent to the vehicle interior side of the soundproof member (60).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a vehicle front structure. BACKGROUND

[0002] In Japanese Patent Application Publication No. 2003-104242, a structure is disclosed in which a pad member is provided at a boundary between a cabin floor and a cabin front wall portion, thereby forming a flat toe board surface.

[0003] However, in a case where the front module of the vehicle is integrally formed by casting, a cabin front wall panel lower member is sometimes integrally formed on the framework portion of the vehicle front portion, and a rib for reinforcement is provided on the cabin front wall panel lower member. In this case, even if the cabin front wall silencer covering the cabin front wall panel is extended downward, it is not possible to ensure the followability to the rib, and noise generated by a tire or the like during running can possibly intrude into the cabin. SUMMARY

[0004] The present disclosure takes the above fact into consideration, and aims to obtain a vehicle front structure capable of suppressing the intrusion of noise into the cabin.

[0005] The vehicle front structure according to the first aspect of the present disclosure is characterized by comprising: a cabin front wall panel lower member integrally formed on a framework portion of a vehicle front portion by casting, and having a rib on an inner side of a cabin; a soundproof member disposed along the rib; a cabin front wall silencer disposed in abutment with a vehicle upper side of the soundproof member; a floor silencer disposed in abutment with a vehicle rear side of the soundproof member; and a pad member disposed in abutment with the inner side of the cabin of the soundproof member.

[0006] In the vehicle front structure according to the first aspect, the cabin front wall panel lower member is integrally formed on the framework portion of the vehicle front portion by casting. On the cabin front wall panel lower member, the rib is formed on the inner side of the cabin, and the rib reinforces the integrally formed framework portion and the cabin front wall panel lower member.

[0007] Here, the pad member for forming a toe board surface on which a passenger's foot is placed is disposed on the inner side of the cabin of the cabin front wall panel lower member. However, in a case where the rib for reinforcement is formed on the cabin front wall panel lower member, there is a case where the followability of the pad member with respect to the rib is insufficient, and an unnecessary gap is generated between the members. Due to such a gap, noise generated outside the cabin easily intrudes into the cabin.

[0008] In the first mode of the vehicle front structure, a sound insulating member is arranged on the vehicle interior side of the under portion of the front wall panel along the rib. Further, a front wall silencer is arranged on the vehicle upper side in abutment with the sound insulating member, a floor silencer is arranged on the vehicle rear side, and a pad member is arranged on the vehicle interior side. Thus, the intrusion of noise through the rib is more effectively suppressed by the sound insulating member. As a result, the intrusion of noise into the vehicle interior is suppressed.

[0009] The second mode of the vehicle front structure of the present disclosure is the structure described in the first mode, in which the sound insulating member is arranged on both sides in the vehicle width direction of the under portion of the front wall panel.

[0010] In the second mode of the vehicle front structure, a sound insulating member is arranged on both sides in the vehicle width direction of the under portion of the front wall panel in the vicinity of the wheel cover. As a result, the intrusion of noise generated by the tire during running is effectively suppressed.

[0011] The third mode of the vehicle front structure of the present disclosure is the structure described in the first mode or the second mode, in which one of the sound insulating member and the pad member has a protrusion and the other has a recess at a portion where the sound insulating member and the pad member abut, and the protrusion and the recess are fitted.

[0012] In the third mode of the vehicle front structure, the protrusion provided on one side and the recess provided on the other side are fitted at a portion where the sound insulating member and the pad member abut. As a result, the positional deviation of the pad member with respect to the sound insulating member is suppressed, and the toe board surface is stabilized.

[0013] The fourth mode of the vehicle front structure of the present disclosure is the structure described in the first mode or the second mode, in which the sound insulating member and the front wall silencer are arranged in abutment with a portion overlapping in the vehicle front-rear direction.

[0014] In the fourth mode of the vehicle front structure, the sound insulating member and the front wall silencer are arranged in abutment with a portion overlapping in the vehicle front-rear direction. As a result, in the case where noise intrudes through the gap between the members, the path length at the time of intrusion can be lengthened. Thus, even in the case where a gap is generated between the members, noise can be attenuated before it penetrates to the vehicle interior side. Further, when the sound insulating member and the front wall silencer are assembled, even in the case where a deviation occurs in the assembly position due to dimensional tolerance or the like, the positional deviation can be absorbed by the amount of overlap in the vehicle front-rear direction. As a result, the robustness in the sound insulating effect is excellent.

[0015] The fifth aspect of the vehicle front structure of the present disclosure is the structure according to the first aspect or the second aspect, in which the sound insulating member and the floor silencer are adjacently arranged with a part overlapping in the vehicle up-and-down direction.

[0016] In the fifth aspect of the vehicle front structure, the sound insulating member and the floor silencer are adjacently arranged with a part overlapping in the vehicle up-and-down direction. Therefore, in the case where noise intrudes through the gap between the members, the path length at the time of intrusion can be lengthened. Therefore, even in the case where a gap is generated between the members, noise can be attenuated before it penetrates to the inside of the passenger compartment. Further, at the time of assembly of the sound insulating member and the floor silencer, even in the case where a deviation is generated in the assembly position due to dimensional tolerance or the like, the deviation in position can be absorbed by the amount of overlap in the vehicle front-and-rear direction. Therefore, the robustness in the sound insulating effect is excellent.

[0017] The sixth aspect of the vehicle front structure of the present disclosure is the structure according to the first aspect or the second aspect, in which the sound insulating member has: a skin layer facing the inside of the passenger compartment and composed of a rubber material; and an intermediate layer configured to be arranged along the rib by deforming in accordance with the shape of the rib.

[0018] In the sixth aspect of the vehicle front structure, the sound insulating member is capable of improving the sound insulating effect by adopting a multilayer structure having the skin layer and the intermediate layer. Further, the sound insulating member is capable of improving the followability to the rib and suppressing the generation of an unnecessary gap between the members by the intermediate layer deforming in accordance with the shape of the rib of the passenger compartment front wall panel lower member.

[0019] The seventh aspect of the vehicle front structure of the present disclosure is the structure according to the sixth aspect, in which the intermediate layer is configured to accommodate a granular cushioning material inside a bag formed of a film-like material.

[0020] In the seventh aspect of the vehicle front structure, the followability of the sound insulating member to the rib can be improved.

[0021] The eighth aspect of the vehicle front structure of the present disclosure is the structure according to the sixth aspect, in which the intermediate layer is composed of a fiber material, and a plurality of notches are formed on the side of the intermediate layer opposite to the rib.

[0022] In the eighth aspect of the vehicle front structure, the followability of the sound insulating member to the rib can be improved since the situation where the portion following the rib is pulled by the surrounding fiber can be suppressed at the time of mounting the sound insulating member.

[0023] As explained above, the vehicle front structure according to the present disclosure is capable of suppressing the intrusion of noise into the passenger compartment. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A cross-sectional view of a vehicle to illustrate the application of the front structure of this embodiment.

[0025] Figure 2 This is a three-dimensional exploded view showing the sound insulation module configured in the front structure of the vehicle according to this embodiment in a partially exploded manner.

[0026] Figure 3 To illustrate along Figure 2 A sectional view of the front of the vehicle cut along line 3-3.

[0027] Figure 4 To indicate along Figure 2 A sectional view of the front of the vehicle cut along line 4-4.

[0028] Figure 5 To represent locally along Figure 3 A sectional view of the sound insulation components and the lower components of the front wall panel of the passenger compartment, cut along line 5-5.

[0029] Figure 6 A cross-sectional view illustrating a first modified example of the sound insulation component according to this embodiment. Detailed Implementation

[0030] The following is for reference Figures 1 to 6 The front structure 10 of the vehicle according to this embodiment will be described. In addition, the arrow FR appropriately shown in each figure indicates the front side of the vehicle, the arrow UP indicates the upper side of the vehicle, and the arrow LH indicates the left side of the vehicle. Furthermore, when the directions front-back, up-down, and left-right are used unless otherwise specified in the following description, they are defined as front-back in the front-back direction, up-down in the up-down direction, and left-right in the direction of travel.

[0031] Furthermore, unless otherwise specified in the specification, the elements are not limited to one and multiple elements may exist. Additionally, in the accompanying drawings, substantially identical elements are marked with the same symbols, and redundant descriptions from the specification are omitted.

[0032] (Overview of the front of the vehicle)

[0033] Figure 1The diagram illustrates a cross-sectional view of the front of a vehicle 12 to which the front structure 10 of this embodiment is applied. The vehicle 12 in this embodiment is, for example, an electric vehicle that is driven by an electric motor (not shown). Examples of electric vehicles include HEV (Hybrid Electric Vehicle), PHEV (Plug-in Hybrid Electric Vehicle), BEV (Battery Electric Vehicle), and FCEV (Fuel Cell Electric Vehicle).

[0034] like Figure 1 As shown, a front transverse member 14, serving as a frame, is disposed at the front of the vehicle 12. The front transverse member 14 extends elongatedly in the vehicle width direction, and its two ends in the vehicle width direction are connected to the lower ends of a pair of left and right pillars 16. The pillars 16 are disposed on both sides in the vehicle width direction as the frame of the vehicle 12. The left and right pillars 16 extend elongatedly in the generally vertical direction of the vehicle, and their upper ends are connected to the front ends of a roof reinforcement member (not shown).

[0035] A pair of side members 15 constituting the frame of the vehicle 12 are disposed on the front side of the front transverse member 14. The pair of side members 15 extend elongatedly in the generally longitudinal direction of the vehicle and are respectively disposed on both sides in the width direction of the vehicle. The rear portions of the pair of side members 15 are connected to the two ends of the front transverse member 14 in the width direction of the vehicle. In addition, a wheel cover (not shown) for accommodating the front wheel (tire) of the vehicle 12 is integrally formed on the rear portions of the pair of side members 15.

[0036] Furthermore, a pair of lower side beams (not shown) constituting the frame portion of the vehicle 12 are disposed on the rear side of the front transverse member 14. The pair of lower side beams extend elongatedly in the generally longitudinal direction of the vehicle and are respectively disposed on both sides in the width direction of the vehicle. The front portions of the pair of lower side beams are connected to the two ends of the front transverse member 14 in the width direction of the vehicle. In addition, the rear portions of the pair of lower side beams are connected to the two ends of the rear transverse member (not shown) in the width direction of the vehicle.

[0037] Furthermore, in vehicle 12, a battery casing (not shown) or multiple battery packs, which house multiple battery packs, is directly supported on a generally rectangular frame formed by the front transverse member 14, the rear transverse member, and a pair of lower side beams. Additionally, the battery packs are modules constructed by stacking multiple battery cells.

[0038] Further, on the substantially rectangular frame formed by the front cross member 14, the rear cross member, the pair of lower side sills, a floor panel 20 that constitutes a floor of the passenger compartment 18 is supported. The floor panel 20 is disposed on the upper side of the battery case or the battery pack, and the outer peripheral portion is connected to the frame. In addition, when the battery case is mounted on the frame formed by the front cross member 14, the rear cross member, the pair of lower side sills, the floor panel 20 is not necessarily required and can be omitted. In this case, the floor of the passenger compartment can also be constituted by the upper surface portion of the battery case.

[0039] As one example, the above-described front cross member 14, the pair of left and right pillars 16, and the pair of left and right side members 15 are formed of a metal such as an aluminum alloy, a magnesium alloy, or the like. Further, the front cross member 14, the pair of left and right pillars 16, and the pair of left and right side members 15 are integrally formed by casting. Therefore, these members have an open cross section that is open in at least one of the vehicle front-rear direction, the vehicle up-down direction, and the vehicle width direction, in correspondence with the direction of demolding of the metal mold for casting. In the example of the present embodiment, the cross section of the front cross member 14 in the vehicle front-rear direction is an open cross section that is open toward the vehicle rear side and the vehicle lower side.

[0040] In addition, it is not necessarily required that the front cross member 14, the pair of left and right pillars 16, and the pair of left and right side members 15 are integrally formed, and a part or all of the members can be formed in a divided manner. Further, in the case where a part or all of the members are formed in a divided manner, the cross-sectional shape of each member can also be a closed cross section.

[0041] (front cross member)

[0042] A front cross member 14 is disposed on the vehicle upper side of the pair of left and right pillars 16. The front cross member 14 supports a front cross member panel 13 that separates the passenger compartment 18 and a power unit room not shown, which is formed on the inner side of the pair of left and right pillars 16, from each other. The power unit room accommodates a motor or the like that supplies driving force during running.

[0043] The front cross member 14 is a substantially rectangular plate-shaped member formed of a metal such as an aluminum alloy, a magnesium alloy, or the like, for example. The front cross member 14 is disposed on the inner side of a substantially rectangular frame formed by the pair of left and right pillars 16 and a front dash panel not shown that connects the vehicle up-down direction intermediate portions of the pair of left and right pillars 16. On the front cross member 14, an opening portion 12 that is open toward the vehicle upper side when viewed in the vehicle front-rear direction is formed, for example, and a front cross member panel 13 is mounted in the opening portion 12. On the front cross member panel 13, a plurality of in-vehicle devices not shown and a wire harness or the like that extends from each in-vehicle device are mounted.

[0044] In this embodiment, the under portion of the front wall panel 22 is cast so as to be integrated with the front cross member 14 and the pair of left and right pillars 16. Therefore, the under portion of the front wall panel 22 is integrated with the upper surface 14A of the front cross member 14 and is erected upward from the upper surface 14A. Further, the vehicle width direction end portions of the under portion of the front wall panel 22 are integrated with the vehicle width direction inner side surfaces of the pair of left and right pillars 16.

[0045] In this embodiment, a plurality of ribs 26 for reinforcement are integrated with the lower portion of the inner side surface 22A of the under portion of the front wall panel 22. Each of the ribs 26 connects the inner side surface 22A of the under portion of the front wall panel 22 and the upper surface 14A of the front cross member 14 and has a substantially triangular shape when viewed in the vehicle width direction. Therefore, the connection portion of the front cross member 14 and the under portion of the front wall panel 22 is reinforced by the ribs 26, and the cross-sectional area of the front cross member 14 is substantially increased at the portions where the ribs 26 are provided. Thus, the rigidity of the under portion of the front wall panel 22 and the front cross member 14 is improved.

[0046] In this embodiment, a plurality of ribs 26 are provided at the right and left vehicle width direction side portions of the under portion of the front wall panel 22, and the both vehicle width direction side portions of the front cross member 14 are reinforced. The both vehicle width direction side portions of the front cross member 14 are connection portions that connect portions of the pair of left and right side members 15 at the rear side in the vehicle, and are located in the vicinity of the wheel covers that are integrated with the side members 15. Therefore, in a case where the both vehicle width direction side portions of the front cross member 14 and the under portion of the front wall panel 22 are reinforced by the ribs 26 so that vibrations of the front wheels (tires) during running are transmitted to the front cross member 14 via the wheel covers and the pair of side members 15, the transmission of the vibrations to the under portion of the front wall panel 22 is suppressed. Thus, noise caused by the vibrations of the front wheels (tires) during running can also be suppressed.

[0047] Further, the above-described structure of the under portion of the front wall panel 22 is merely an example and is not necessarily required. For example, the under portion of the front wall panel 22 can be integrated with the front cross member 14, and the pillars 16 can be formed in a separate body. Further, the arrangement of the ribs 26 for reinforcement is merely an example, and the structure in which the ribs 26 are provided at the central portion in the vehicle width direction of the under portion of the front wall panel 22 can also be provided.

[0048] (Sound Insulation Module)

[0049] As Figure 1As shown, a sound insulation module 30 is arranged on the inner side of the vehicle cabin in the vehicle cabin front wall panel 24, the vehicle cabin front wall panel lower member 22, and the floor panel 20.

[0050] Figure 2 A perspective view of the sound insulation module 30 is shown in a partially exploded manner. As shown, the sound insulation module 30 is configured to include a vehicle cabin front wall silencer 40, a floor silencer 50, a sound insulation member 60, and a cushion member 70. Further, the upper surface of the sound insulation module 30 is covered by a floor carpet 32 (a skin material) that constitutes the design surface of the floor of the vehicle cabin 18. In addition, the floor carpet 32 is configured by a carpet skin and a rubber material, for example. The floor carpet 32 can be integrally configured with the floor silencer 50 by being joined to the floor silencer 50, or can be configured in a separate body by being placed on the floor silencer 50 as in the present embodiment. Figure 2

[0051] (Vehicle cabin front wall silencer)

[0052] The vehicle cabin front wall silencer 40 is a thin sheet-shaped member having sound blocking and sound absorbing properties, and is mainly installed on the entire side of the inner side of the vehicle cabin in the vehicle cabin front wall panel 24 (covers the side of the inner side of the vehicle cabin in the vehicle cabin front wall panel 24).

[0053] If described in more detail, the vehicle cabin front wall silencer 40 is formed in a substantially T shape, for example, when viewed in the vehicle front-rear direction, and extends in the vehicle width direction and the vehicle up-down direction. The vehicle cabin front wall silencer 40 is configured by a base portion 42 having a substantially rectangular shape that constitutes the portion on the upper side of the vehicle, and an extension portion 44 that extends from the central portion in the vehicle width direction of the base portion 42 toward the lower side of the vehicle, for example.

[0054] The base portion 42 is arranged so as to span the portion on the upper side of the vehicle of the vehicle cabin front wall panel 24 and the vehicle cabin front wall panel lower member 22, and covers the entire side of the inner side of the vehicle cabin in the vehicle cabin front wall panel 24, and the upper portion of the side 22A of the inner side of the vehicle cabin in the vehicle cabin front wall panel lower member 22. The both side portions in the vehicle width direction of the base portion 42 are contiguous with the upper side of the sound insulation member 60 described later at the lower end portions.

[0055] The extension portion 44 covers the central portion in the vehicle width direction of the portion on the lower side of the vehicle of the vehicle cabin front wall panel lower member 22. The lower end portion of the extension portion 44 is contiguous with the front end portion of the floor silencer 50 described later. Further, the both end portions in the vehicle width direction of the extension portion 44 are contiguous with the inner side in the vehicle width direction of the sound insulation member 60 described later.

[0056] (Floor silencer)

[0057] ​The floor silencer 50 is a thin sheet-shaped member having sound blocking and sound absorbing properties, and is mainly installed on the entire side surface (upper surface) of the vehicle interior side of the floor panel 20 (covers the side surface of the vehicle interior side of the floor panel 20).

[0058] If described in more detail, the floor silencer 50 has a substantially rectangular shape when viewed in the vehicle up-down direction. As one example, the floor silencer 50 is composed of a substantially rectangular base portion 52 that covers the entire side surface of the vehicle interior side of the floor panel 20, and an extension portion 54 that extends from the central portion in the vehicle width direction to the vehicle front side and the vehicle upper side at the front end side of the base portion 52.

[0059] The both side portions in the vehicle width direction of the base portion 52 are contiguous with the vehicle rear side of the sound insulating member 60 described later at the front end portion. In addition, both end portions in the vehicle width direction of the extension portion 54 are contiguous with the vehicle width direction inner side of the sound insulating member 60. In addition, the upper end portion (front end portion) of the extension portion 54 is contiguous with the vehicle lower side of the base portion 42 of the vehicle front wall silencer 40.

[0060] (Sound Insulating Member)

[0061] The sound insulating member 60 is a tile-shaped member having sound blocking and sound absorbing properties, and is mainly configured to cover the plurality of ribs 26 provided on the vehicle front wall panel lower member 22 from the vehicle interior side (covers the plurality of ribs 26). Therefore, in the present embodiment, the left and right pair of sound insulating members 60 are disposed on both side portions in the vehicle width direction of the vehicle front wall panel lower member 22.

[0062] If described in more detail, the sound insulating member 60 has a substantially rectangular shape when viewed in the vehicle front-rear direction, and extends in the vehicle width direction and the vehicle up-down direction. The sound insulating member 60 is formed with a plurality of protrusions 62 on the side surface 60A facing the vehicle interior side. The plurality of protrusions 62 are configured to protrude toward the vehicle interior side and are fitted into a plurality of recesses 72 formed on the opposite surface of the gasket member 70 described later. In addition, the number of protrusions 62 can be appropriately changed, and for example, can be one.

[0063] As one example, each protrusion 62 has a substantially triangular shape and is tapered toward the vehicle upper side. By tapering each protrusion 62, the workability or the accuracy of positioning at the time of assembly can be improved by inserting the tapered end portion into the recess 72.

[0064] Further, the side surface 60B of the sound insulating member 60 facing the lower part of the vehicle cabin front wall panel 22 is in a three-dimensional shape along the rib 26. In other words, the side surface 60B of the sound insulating member 60 facing the lower part of the vehicle cabin front wall panel 22 is arranged along the rib 26. In more detail, as described later, the pocket 64 constituting the intermediate layer 602 of the sound insulating member 60 is deformed following the shape of the rib 26. Thereby, the side surface 60B (the pocket 64) facing the lower part of the vehicle cabin front wall panel 22 is arranged along the rib 26.

[0065] In the present embodiment, the vehicle cabin front wall silencer 40 is arranged adjacent to the vehicle upper side (upper end portion) of the sound insulating member 60. Further, the floor silencer 50 is arranged adjacent to the vehicle rear side (lower end portion) of the sound insulating member 60. Further, the vehicle cabin front wall silencer 40 and a part of the floor silencer 50 are arranged adjacent to the vehicle width direction inner side of the sound insulating member 60.

[0066] (Pad member)

[0067] The pad member 70 is a tile-shaped member having impact absorption properties, and is constituted by, for example, a foamed resin molded body formed by incorporating a foaming agent into a resin material such as a polypropylene resin or a polystyrene resin and heating and molding. The pad member 70 is arranged mainly adjacent to the vehicle cabin inner side of the sound insulating member 60. In the present embodiment, the left and right pair of pad members 70 are arranged so as to cover the pair of sound insulating members 60 from the vehicle cabin inner side, respectively.

[0068] The side surface of the pad member 70 on the vehicle cabin inner side forms a toe board surface on which the soles of the feet of an occupant seated on a seat S constituting a driver's seat or a front passenger's seat of the vehicle 12 are placed, and becomes a flat surface. Further, the pad member 70 adjusts the thickness of each portion so as to form a surface continuous with the vehicle cabin front wall silencer 40 and the floor silencer 50 adjacent to each other.

[0069] Further, in the pad member 70, on the side surface (vehicle cabin outer side surface) opposite to the sound insulating member 60, a plurality of recessed portions 72 corresponding to the plurality of protruding portions 62 provided on the sound insulating member 60 are formed. The shape of the recessed portion 72 becomes a substantially triangular shape corresponding to the shape of the protruding portion 62 of the sound insulating member 60. The pad member 70 causes the plurality of protruding portions 62 provided on the sound insulating member 60 to be engaged with the plurality of recessed portions 72, thereby suppressing positional displacement with respect to the sound insulating member 60.

[0070] [Transmission loss of sound insulating module]

[0071] Next, the transmission loss (TL) of the soundproofing module 30 will be described. The transmission loss is a value measured using the difference (difference in sound pressure level) between the sound incident on the material layer such as a wall and the sound that has passed through the material layer and entered the vehicle cabin. Therefore, in terms of improving the soundproofing performance of the vehicle cabin 18, the greater the transmission loss of the soundproofing module 30, the more preferable it is.

[0072] It is known that, in the case of a single layer of a material that is homogeneous, the greater the mass per unit area, the higher the frequency, and the greater the value of the transmission loss. Therefore, in the soundproofing module 30 of the present embodiment, in the case where the vehicle cabin front wall silencer 40, the floor silencer 50, and the soundproofing member 60 are each composed of a single layer of material, in order to ensure the transmission loss, it is preferable to increase the mass of each member. However, in this case, if the transmission loss is prioritized, the problem of an increase in the weight of the soundproofing module arises.

[0073] On the other hand, in the case where the material is a multilayer structure including an air layer, the transmission loss varies due to the "spring-mass model" based on the structure of the material layer (mass layer) having a greater mass and the air layer having a smaller mass. That is, it has the characteristic that resonance occurs at a specific frequency by the air layer functioning as a spring, and the transmission loss becomes greater above this frequency band.

[0074] Furthermore, it is known that, in the case where the vibration of the material forming a double layer structure is calculated using the skin vibration in the known "spring-mass model", the resonance frequency f0 is proportional to the square root of the ratio of the spring constant k of the intermediate layer (air layer) on the inside to the mass m of the skin layer (mass layer), as represented by the following (Formula 1).

[0075] (Formula 1)

[0076]

[0077] Therefore, in a material of a double layer structure, in terms of improving the soundproofing performance of the vehicle cabin 18, the greater the mass of the skin layer (mass layer), the more preferable it is, and the smaller the spring constant of the intermediate layer (air layer), the more preferable it is.

[0078] According to the characteristics of the multilayer structure material described above, in the soundproofing module 30 of the present embodiment, from the viewpoint of improving the soundproofing performance while suppressing the weight, the vehicle cabin front wall silencer 40 and the soundproofing member 60 are composed of a material of a multilayer structure (in the present embodiment, a double layer structure). In addition, the floor silencer 50 of the present embodiment constitutes a "spring-mass model" of a multilayer structure (double layer structure) together with the floor carpet 32.

[0079] Specifically, asFigure 3 As shown, in the front wall muffler 40 and the floor muffler 50, the outer layers 401 and 501 are, for example, made of rubber material, while the inner intermediate layers 402 and 502 are made of fiber material or polyurethane material. Additionally, the outer layer 501 of the floor muffler 50 is made of floor carpet 32. While the materials of the intermediate layers 402 and 502 are not particularly limited, when they are made of fiber material, by including air between the fibers, they become spring-like layers in relation to the outer layers 401 and 501. Examples of fiber materials include felt or non-woven fabric; in this embodiment, felt material is used.

[0080] In addition, such as Figures 3 to 5 As shown, the outer skin layer 601 of the sound insulation component 60 is made of rubber material, and a protrusion 62 is integrally formed on the inner side 60A of the vehicle compartment. Furthermore, the middle layer 602 of the sound insulation component 60 is constructed such that granular cushioning material 66 is contained within a bag 64 formed of a thin-film material (e.g., polyvinyl chloride). The type of cushioning material 66 is not particularly limited, as long as its mass per unit volume is small compared to the material of the outer skin layer 601. For example, it can be made of resin material, wood, foam material, etc., or it can be a granular cushioning material formed by mixing multiple of these materials. Alternatively, it can be a granular substance formed by grinding waste into powder. By containing air between the particles, the middle layer 602 becomes a spring-like layer in relation to the outer skin layer 601.

[0081] In addition, in this embodiment, in order to improve the following of the lower component 22 of the front wall panel of the carriage relative to the rib 26, the intermediate layer 602 of the sound insulation component 60 has a softer property compared with the intermediate layers 402 and 502 of the front wall muffler 40 and the floor muffler 50.

[0082] [Regarding the robustness of the sound insulation module]

[0083] Next, the robustness of the sound insulation module 30 will be explained. Ideally, no gaps should occur between the components constituting the sound insulation module 30 in terms of shielding noise generated outside the vehicle compartment. However, when assembling multiple components, deviations in assembly position may sometimes occur due to dimensional tolerances of each component, resulting in gaps between the components.

[0084] Therefore, in the sound insulation module 30 of this embodiment, the adjacent components are configured in a partially overlapping manner at the portions where the sound insulation component 60 is adjacent to the front wall muffler 40 of the carriage and the portions where the sound insulation component 60 is adjacent to the floor muffler 50.

[0085] Specifically, in the portion where the sound insulation component 60 and the front wall muffler 40 of the passenger compartment are adjacent, the sound insulation component 60 and the front wall muffler 40 are arranged adjacent to each other with a portion overlapping in the vehicle's longitudinal direction. Here, in the front wall muffler 40, the lower ends of both sides of the base portion 42 in the vehicle width direction and the end portions of the extension portion 44 in the vehicle width direction adjacent to the sound insulation component 60 are adjacent to the sound insulation component 60. At these ends of the front wall muffler 40, a height difference portion 46 facing the interior of the passenger compartment is formed, and the thickness of the plate at the end is thinner (see reference). Figure 3 as well as Figure 4 By overlapping the adjacent ends of the sound insulation component 60 from the inside (front) of the passenger compartment onto the height difference portion 46, the ends are overlapped in the longitudinal direction of the vehicle. At this time, the intermediate layer 602 of the sound insulation component 60 deforms following the height difference portion 46 of the passenger compartment front wall muffler 40, and is thus positioned along the height difference portion 46. Therefore, in this embodiment, the side surface of the passenger compartment inside the passenger compartment of the passenger compartment front wall muffler 40 and the side surface 60A (skin layers 401, 601) of the sound insulation component 60 on the passenger compartment inside side become continuous surfaces.

[0086] Furthermore, the same applies to the portion of the sound insulation component 60 adjacent to the floor muffler 50. The sound insulation component 60 and the floor muffler 50 are arranged adjacent to each other with a portion overlapping in the vertical direction of the vehicle. Here, in the floor muffler 50, the front ends of both sides of the base portion 52 in the vehicle width direction and the end portions of the extension portion 54 in the vehicle width direction adjacent to the sound insulation component 60 are adjacent to the sound insulation component 60. At these ends of the floor muffler 50, a height difference portion 56 facing the interior of the passenger compartment is formed, and the thickness of the plate at the ends decreases (see reference). Figure 3 By overlapping adjacent ends of the sound insulation component 60 from the inside (upper) side of the vehicle compartment onto the height difference portion 56, the ends are overlapped in the vertical direction of the vehicle. At this time, the intermediate layer 602 of the sound insulation component 60 deforms following the height difference portion 56 of the floor muffler 50, and is thus positioned along the height difference portion 56. In this embodiment, with the surface of the sound insulation component 60 covered by the padding component 70, the inner side surface of the floor muffler 50 (intermediate layer 502) and the inner side surface of the padding component 70 become continuous surfaces.

[0087] As described above, since the members are configured in a manner that each of the members abut each other with a partial overlap, in a case where noise intrudes through a gap between the members, a path length at the time of intrusion can be lengthened. That is, in the present embodiment, the path length becomes along the steps 46, 56, and is longer than the path length in a case where a gap between straight end surfaces of the members is used. Therefore, even in a case where a gap is generated between the members, noise can be attenuated before the noise penetrates to the inside of the passenger compartment. Further, even in a case where a deviation occurs in the assembly position between the members due to a dimensional tolerance or the like, the deviation in the position is absorbed by the amount of overlap of the end portions, so that a gap is difficult to be generated. Therefore, the robustness in the soundproofing effect is excellent.

[0088] (Action and Effect)

[0089] As described above, in the vehicle front structure 10 of the present embodiment, the under member 22 of the front wall panel of the passenger compartment is integrally formed on the framework of the front portion of the vehicle by casting. On the under member 22 of the front wall panel of the passenger compartment, the rib 26 is formed on the inside of the passenger compartment, which reinforces the integrally formed framework and the under member 22 of the front wall panel of the passenger compartment.

[0090] Here, generally, a pad member for forming a toe panel surface on which a passenger's foot is placed is disposed on the inside of the passenger compartment of the under member of the front wall panel of the passenger compartment. However, in a case where the rib 26 for reinforcement is formed on the under member 22 of the front wall panel of the passenger compartment as in the present embodiment, there is a case where the pad member does not follow the rib 26 sufficiently, and a gap is generated between the members. Due to such a gap, noise generated outside the passenger compartment easily intrudes into the passenger compartment.

[0091] In contrast, in the vehicle front structure 10, the soundproof member 60 is disposed along the rib 26 on the inside of the passenger compartment of the under member 22 of the front wall panel of the passenger compartment. Further, the front wall silencer 40 is disposed on the upper side of the vehicle in a manner that the soundproof member 60 abuts the front wall silencer 40, the floor silencer 50 is disposed on the rear side of the vehicle, and the pad member 70 is disposed on the inside of the passenger compartment. Therefore, the intrusion of noise through the rib 26 is effectively suppressed by the soundproof member 60. Thus, the intrusion of noise into the passenger compartment is suppressed.

[0092] Further, in the present embodiment, the soundproof member 60 is disposed at both sides in the vehicle width direction of the under member 22 of the front wall panel of the passenger compartment in the vicinity of the wheel house. Thus, the intrusion of noise generated by the tire at the time of running can be effectively suppressed.

[0093] Further, in the present embodiment, the protrusion 62 provided on the soundproof member 60 and the recess 72 provided on the gasket member 70 are fitted at the portion where the soundproof member 60 and the gasket member 70 are adjacent to each other. Thus, it is possible to suppress the positional deviation of the gasket member 70 with respect to the soundproof member 60 and to stabilize the toe board surface. Alternatively, a structure in which a protrusion provided on the gasket member and a recess provided on the soundproof member are fitted can be adopted.

[0094] Further, in the present embodiment, the soundproof member 60 and the front wall silencer 40 are arranged adjacent to each other with a portion of the soundproof member 60 overlapping the front wall silencer 40 in the vehicle front-rear direction, and the soundproof member 60 and the floor silencer 50 are arranged adjacent to each other with a portion of the soundproof member 60 overlapping the floor silencer 50 in the vehicle up-down direction. Thus, in the case where noise intrudes through the gap between the members, the path length at the time of intrusion becomes long, so it is possible to attenuate the noise before it penetrates through the gap. Further, even in the case where a deviation occurs in the assembly position due to dimensional tolerance or the like, since it is possible to absorb the deviation in the position with the amount of overlap between the members, the robustness in the soundproofing effect is excellent.

[0095] (First Modification of Soundproofing Member)

[0096] In the above embodiment, the intermediate layer 602 of the soundproof member 60 is configured to accommodate the granular cushioning material 66 in the pocket 64, but is not limited thereto. The structure of the soundproof member 80 according to the first modification shown in FIG. 8 can be applied. Figure 6 As with the front wall silencer 40 and the floor silencer 50, the skin layer 801 of the soundproof member 80 facing the inside of the passenger compartment is made of a rubber material or the like, and the inside intermediate layer 802 is made of a fiber material or a polyurethane material or the like. Even in this case, in the case where the intermediate layer 802 is made of a fiber material or a polyurethane material or the like, it is possible to include air between the fibers or between the foamed cells, so as to become a layer having a spring property like an air layer in relation to the skin layer 801, and thus it is possible to ensure the transmission loss.

[0097] Further, in the first modification, a plurality of notches 82 (cutouts) are formed on the side surface of the intermediate layer 802 of the soundproof member 80 opposite to the rib 26. Thus, when the soundproof member 80 is mounted on the side surface 22A of the front wall panel lower member 22, since it is possible to suppress the portion following the rib 26 from being pulled by the surrounding fibers, it is possible to improve the followability of the soundproof member 60 with respect to the rib 26.

[0098] (Second Modification of Soundproofing Member)

[0099] Further, although not illustrated, in the case where the soundproofing member is composed of a material of a double-layer structure, the skin layer can be composed of a rubber material, and the intermediate layer can be composed of a sponge material such as polyurethane or a granular sponge material. In this case, since the soundproofing member can be formed by molding using a metal mold, it can be easily formed to follow the shape of the rib 26.

[0100] Further, although in the above-described embodiments, the vehicle cabin front wall silencer 40, the floor silencer 50, and the soundproofing member 60 are composed of a material of a multi-layer structure, they are not limited thereto, and can be composed of a material of a single-layer structure.

Claims

1. A vehicle front structure characterized by comprising: Possessing: a vehicle cabin front wall panel lower member which is integrally formed with a frame portion of a vehicle front portion by casting, and has a rib on an inside of a vehicle cabin; a soundproof member which is arranged along the rib; a vehicle cabin front wall silencer which is arranged in abutment with a vehicle upper side of the soundproof member; a floor silencer which is arranged in abutment with a vehicle rear side of the soundproof member; a gasket member which is arranged in abutment with the inside of the vehicle cabin of the soundproof member.

2. The vehicle front portion structure according to claim 1, wherein the soundproof member is arranged on both sides in a vehicle width direction of the vehicle cabin front wall panel lower member.

3. The vehicle front portion structure according to claim 1 or claim 2, wherein at a portion where the soundproof member and the gasket member are in abutment, one of the soundproof member and the gasket member has a protrusion, and the other has a recess, the protrusion and the recess being fitted.

4. The vehicle front portion structure according to claim 1 or claim 2, wherein the soundproof member and the vehicle cabin front wall silencer are arranged in abutment with a portion overlapping in a vehicle front-rear direction.

5. The vehicle front portion structure according to claim 1 or claim 2, wherein the soundproof member and the floor silencer are arranged in abutment with a portion overlapping in a vehicle up-down direction.

6. The vehicle front portion structure according to claim 1 or claim 2, wherein the soundproof member has: a skin layer which faces the inside of the vehicle cabin, and is made of a rubber material; an intermediate layer which is deformed by following a shape of the rib to be arranged along the rib.

7. The vehicle front portion structure according to claim 6, wherein the intermediate layer is made in a manner that a granular cushioning material is housed inside a bag formed of a film-like material.

8. The vehicle front portion structure according to claim 6, wherein the intermediate layer is made of a fiber material, and a plurality of notches are formed on a side of the intermediate layer which opposes the rib.

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