JP7593194B2 - Vehicle panel structure - Google Patents

Description

The present invention relates to a vehicle panel structure that is made up of a double-wall panel in which a sealed hollow layer (middle layer) is formed between an outer wall located on the outside of the vehicle and an inner wall located on the inside of the vehicle.

Research is underway to improve the quietness of the vehicle interior by constructing parts of the vehicle with double-wall panels like those described above, thereby preventing the intrusion of acoustic energy from outside the vehicle into the interior.

Double-wall panels are an effective way to improve quietness (sound insulation) inside a vehicle cabin, but because they have a hollow structure, it is difficult to ensure their rigidity. Therefore, when applying them to vehicles, the main challenge is to ensure sufficient rigidity as well as sound insulation.

One solution to this problem is disclosed in, for example, Patent Document 1. This document 1 discloses a vehicle floor structure to which a double-wall panel is applied. Specifically, ribs are provided that divide the hollow layer between the upper and lower plate sections that make up the floor into multiple spaces (cells), thereby improving the panel rigidity while maintaining the hollow layer.

JP 2018-177126 A

However, in a panel structure in which ribs are provided between the upper and lower panels, the ribs themselves become a propagation path for acoustic energy, so although the panel rigidity is increased, sound insulation is sacrificed. In particular, in a structure in which the hollow layer is divided into many cells by ribs, as in Patent Document 1, it is thought that although the rigidity of the floor can be ensured, it is difficult to achieve high sound insulation.

The present invention was made in consideration of the above circumstances, and aims to provide a vehicle panel structure that can achieve high levels of both vehicle rigidity and quietness inside the vehicle cabin.

As described above, there is a trade-off between the panel rigidity and sound insulation of a double-wall panel. The inventors of the present application conducted extensive research in consideration of this point, and as a result, found that, as will be described in detail later, when the hollow layer of a double-wall panel is divided into a predetermined number of parts, it is possible to achieve both panel rigidity and sound insulation at a relatively high level. The present invention has been made based on this finding. That is, the present invention relates to a vehicle panel structure comprising a double-wall panel having an outer wall and an inner wall facing each other in the inside-outside direction of a vehicle, and a sealed hollow layer formed between the outer wall and the inner wall, the panel structure including partition walls interposed between the outer wall and the inner wall and dividing the hollow layer into any number of areas from 4 to 8, the partition walls being formed with one or more communication parts that communicate adjacent areas with each other across the partition walls, the communication parts being formed at the ends of the partition walls on the outer wall side, the partition is formed with a plurality of first communicating portions which are communicating portions consisting of the notches and which are arranged at a predetermined interval in the extension direction of the partition, and a plurality of second communicating portions which are communicating portions consisting of through holes which penetrate the partition in its thickness direction and which are arranged at a predetermined interval in the extension direction at a position closer to the inner wall than the first communicating portions, and the first communicating portions and the second communicating portions are arranged in a staggered arrangement in which the arrangement pitch is shifted from each other in the extension direction .

In this way, by providing partitions so that the number of divisions of the hollow layer is any number between 4 and 8, it is possible to achieve both rigidity and sound insulation at a relatively high level, even with the provision of partitions, as shown in the analysis results described below. Therefore, with the above-mentioned vehicle panel structure, it is possible to achieve a higher level of vehicle rigidity and quietness inside the vehicle cabin.
In addition, since the communication portion impedes the propagation of acoustic energy in the partition wall, the propagation of acoustic energy from the outer wall to the inner wall through the partition wall is suppressed. In addition, since adjacent areas are connected to each other, it is possible to increase the transmission loss caused by the propagation of acoustic energy through the hollow layer (air layer) compared to when no communication portion is provided in the partition wall. This contributes to improving sound insulation.
In addition, the cutouts limit the path of acoustic energy from the outer wall to the partition wall, effectively suppressing the propagation of acoustic energy through the partition wall. In this case, the first and second communication parts, each of which is a cutout, are arranged in a staggered pattern, making it difficult for acoustic energy to propagate from the outer wall side to the inner wall side, thereby contributing to improved sound insulation.

In this case, it is preferable that the partition divides the hollow layer into four, six, or eight equal areas.

With this configuration, the hollow layer is evenly divided, making it possible to ensure more uniform rigidity and sound insulation throughout the double-wall panel.

In the above panel structure, it is preferable that the partition walls include a first partition wall that extends linearly in a first direction along the outer wall and the inner wall, and a second partition wall that extends linearly in a second direction that intersects with the first direction and extends linearly along the outer wall and the inner wall.

With this structure, the length of the partitions (first and second partitions) can be made shorter than when the partitions are curved or bent. This reduces the propagation of acoustic energy from the outer wall to the inner wall through the partitions, which is advantageous in ensuring sound insulation.

In this case, it is preferable that the communication portion has an elongated shape extending along the extension direction of the partition wall.

With this structure, the communication section can effectively block the propagation path of acoustic energy from the exterior wall to the partition wall, further contributing to improved sound insulation.

In this case, it is further preferable that the first communication portion and the second communication portion have an overlapping region in the extension direction.

This structure makes it more difficult for acoustic energy to propagate from the exterior wall to the interior wall. This further contributes to improved sound insulation.

The present invention relates to a vehicle panel structure consisting of a double-wall panel having an outer wall and an inner wall facing each other in the interior-exterior direction of the vehicle, with a sealed hollow layer formed between the outer wall and the inner wall, and further comprising a partition interposed between the outer wall and the inner wall to divide the hollow layer into any number of areas between 4 and 8, and one or more communication portions are formed in the partition to connect adjacent areas across the partition, and the partition is composed of a partition main body and a viscoelastic member interposed between the partition main body and the outer wall, and the viscoelastic members are provided at a plurality of positions along the partition main body that are spaced apart from each other, thereby forming the communication portions between adjacent viscoelastic members.

In this way, by providing partitions so that the number of divisions of the hollow layer is any number between 4 and 8, it is possible to achieve both rigidity and sound insulation at a relatively high level, even with the provision of partitions, as shown in the analysis results described below. Therefore, with the above-mentioned vehicle panel structure, it is possible to achieve a higher level of vehicle rigidity and quietness inside the vehicle cabin.
In addition, since the communication portion impedes the propagation of acoustic energy in the partition wall, the propagation of acoustic energy from the outer wall to the inner wall through the partition wall is suppressed. In addition, since adjacent areas are connected to each other, it is possible to increase the transmission loss caused by the propagation of acoustic energy through the hollow layer (air layer) compared to when no communication portion is provided in the partition wall. This contributes to improving sound insulation.
In addition, the acoustic energy incident on the outer wall propagates through the viscoelastic member to the inner wall, and in the process, a part of the acoustic energy (vibration energy) is converted to thermal energy, which makes it difficult for the acoustic energy to propagate from the outer wall to the inner wall, thereby contributing to improving sound insulation.

In this case, the partition body has a T-shaped cross section with a partition main portion extending from the inner wall toward the outer wall and flange portions extending from the tip of the partition main portion to both sides along the outer wall, and the viscoelastic member is preferably interposed between the flange portions and the outer wall.

This structure allows a larger area to be occupied by the viscoelastic material between the bulkhead body and the outer wall, improving the effect of suppressing the propagation of acoustic energy through the energy conversion.

The present invention also relates to a vehicle panel structure consisting of a double-wall panel having an outer wall and an inner wall facing each other in the interior-exterior direction of the vehicle, and a sealed hollow layer formed between the outer wall and the inner wall, and a partition wall is provided between the outer wall and the inner wall to divide the hollow layer into any number of areas from 4 to 8, and the partition wall has one or more communication portions formed therein to connect adjacent areas across the partition wall, and the partition wall is composed of an inner wall-side partition wall portion extending from the inner wall toward the outer wall, an outer wall-side partition wall portion extending from the outer wall toward the inner wall and facing the inner wall-side partition wall portion, and a viscoelastic member interposed between the inner wall-side partition wall portion and the outer wall-side partition wall portion, and the viscoelastic member is provided at a plurality of positions spaced apart from each other along the inner wall-side partition wall portion and the outer wall-side partition wall portion, thereby forming the communication portions between adjacent viscoelastic members.

In this way, by providing partitions so that the number of divisions of the hollow layer is any number between 4 and 8, it is possible to achieve both rigidity and sound insulation at a relatively high level, even with the provision of partitions, as shown in the analysis results described below. Therefore, with the above-mentioned vehicle panel structure, it is possible to achieve a higher level of vehicle rigidity and quietness inside the vehicle cabin.
In addition, since the communication portion impedes the propagation of acoustic energy in the partition wall, the propagation of acoustic energy from the outer wall to the inner wall through the partition wall is suppressed. In addition, since adjacent areas are connected to each other, it is possible to increase the transmission loss caused by the propagation of acoustic energy through the hollow layer (air layer) compared to when no communication portion is provided in the partition wall. This contributes to improving sound insulation.
This structure also allows a portion of the acoustic energy (vibration energy) to be converted into thermal energy, which makes it difficult for the acoustic energy to propagate from the outer wall to the inner wall, thereby contributing to improved sound insulation.

The panel structure in question is any one of the following panel structures: a floor panel, a dash panel, a roof panel, and a door panel.

This structure ensures high levels of quietness by preventing outside noise, such as road noise and driving sounds, from entering the cabin while maintaining the vehicle's rigidity.

As described above, the vehicle panel structure of the present invention makes it possible to achieve high levels of both vehicle rigidity and quietness inside the vehicle cabin.

1 is a perspective view of an automobile body to which a panel structure according to the present invention is applied; 1 is a partial cross-sectional view of a vehicle body including a floor panel. FIG. 2 is a perspective view of a double wall panel that constitutes a floor panel. FIG. 2 is a cross-sectional view of a portion of a double wall panel. 1 is a diagram (graph) showing the relationship between torsional rigidity and transmission loss of a double-wall panel. 1A and 1B are schematic diagrams showing models of double-walled panels used in CAE analysis, in which (a) shows a model in which the hollow layer is divided into four equal parts, (b) shows a model in which the hollow layer is divided into four equal parts by diagonal partitions, (c) shows a model in which the hollow layer is divided into eight equal parts, and (d) shows a model in which the hollow layer is divided into 32 equal parts. FIG. 11 is a cross-sectional view showing a portion of a double-wall panel according to a modified example. FIG. 11 is a cross-sectional view showing a portion of a double-wall panel according to a modified example. 9A and 9B are cross-sectional views showing a portion of a double-wall panel relating to a modified example, where (a) is a cross-sectional view of a main portion of the double-wall panel along the vehicle width direction, and (b) is a cross-sectional view along line IX-IX of (a). 1A is a cross-sectional view showing a portion of a double-wall panel according to a modified example, FIG. 1A is a cross-sectional view of a main portion of the double-wall panel along the vehicle width direction, and FIG. 1B is a cross-sectional view along line X-X of FIG.

A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[Body structure]
Fig. 1 is a perspective view of an automobile body to which the vehicle panel structure according to the present invention is applied. In Fig. 1, reference numeral 1 denotes an engine room 1 (a motor room in the case of an electric vehicle), and reference numeral 2 denotes a passenger compartment. A dash panel 3 is provided between the engine room 1 and the passenger compartment 2, dividing the vehicle in the front-rear direction. Aprons 4 extend from upper portions of both sides of the dash panel 3 in the vehicle width direction toward the front of the vehicle, and a pair of left and right front side frames 5 are provided below the apron 4 and on the inner side in the vehicle width direction, each of which extends from the dash panel 3 toward the front of the vehicle. A bumper beam 6 extending in the vehicle width direction is attached to the front ends of these front side frames 5 via crash cans.

A floor panel 7 that forms the floor surface of the passenger compartment 2 is connected to the lower rear end of the dash panel 3, and a tunnel section 8 that bulges into the passenger compartment 2 and extends in the front-to-rear direction of the vehicle is provided in the center of the floor panel 7 in the vehicle width direction. A kick-up section 9 that extends in the vertical direction is provided at the rear end of the floor panel 7, and a rear floor 10 is connected to the rear of the kick-up section 9.

A hinge pillar 11 extending in the vertical direction of the vehicle is provided on each of the two ends of the dash panel 3 in the vehicle width direction. A side sill 12 extending in the longitudinal direction of the vehicle is connected to the lower end of each hinge pillar 11, and a front pillar 13 extending at an angle toward the rear and upward of the vehicle is connected to the upper end of each hinge pillar 11.

A roof side rail 14 extending in the fore-and-aft direction of the vehicle is connected to the rear end of the front pillar 13, and a rear pillar 15 extending toward the rear and downward of the vehicle is connected to the rear end of the roof side rail 14.

The longitudinal middle portion of the roof side rail 14 and the longitudinal middle portion of the side sill 12 are connected by a center pillar 16 extending in the vertical direction. A front door opening 17 is formed surrounded by the hinge pillar 11, the front pillar 13, the roof side rail 14, the center pillar 16, and the side sill 12, and a front door (not shown) is assembled in this front door opening 17 so that it can be opened and closed.

The rear of the roof side rail 14 and the rear of the side sill 12 are connected in the vertical direction by an intermediate pillar 19 and a rear wheel house section 20. A rear door opening 21 is formed, surrounded by the center pillar 16, roof side rail 14, intermediate pillar 19, rear wheel house section 20, and side sill 12, and a rear door (not shown) is installed in this rear door opening 21 so that it can be opened and closed.

A front header 22 extending in the vehicle width direction is connected to the upper ends of the left and right front pillars 13, and a rear header 23 extending in the vehicle width direction is connected to the upper ends of the left and right rear pillars 15. A roof panel 24 is installed in the space surrounded by the front header 22, rear header 23, and left and right roof side rails 14.

Figure 2 is a partial cross-sectional view of the vehicle body, mainly the lower part, i.e., including the floor panel 7 (cross-sectional view taken along line II-II in Figure 1).

The tunnel section 8 comprises a main body 30 having a gate-shaped cross section, and lateral protrusions 32 that protrude outward in the vehicle width direction from the lower portions on both the left and right sides of the main body 30. The lateral protrusions 32 have a closed cross-sectional structure with a rectangular cross section (rectangular or square in this example) extending in the front-rear direction, and are formed integrally with the main body 30. Reinforcing nodes are provided at multiple locations in the front-rear direction inside the lateral protrusions 32.

The lower opening of the tunnel section 8 is covered with a tunnel cover member 36. The exhaust pipe Ep (or the propeller shaft) is disposed in the space surrounded by the tunnel section 8 and the tunnel cover 36.

The side sill 12 has a closed cross-sectional structure with a rectangular cross-section (rectangular or square in this example) extending in the fore-aft direction. Reinforcement nodes are provided at multiple locations in the fore-aft direction inside the side sill 12 to protect against side impact loads.

As shown in FIG. 2, the upper surface of the side sill 12 and the upper surface of the lateral protrusion 32 in the tunnel section 8 are set at approximately the same height, and a seat support frame (not shown) for supporting a seat is attached horizontally across the upper surface of the side sill 12 and the upper surface of the lateral protrusion 32 on both the left and right sides of the tunnel section 8.

The floor panel 7 is fitted between the inner surface 12a of the side sill 12 and the outer surface 32a of the lateral protrusion 32 on both the left and right sides of the tunnel section 8. Although not shown in FIG. 2, the inner surface 12a and the outer surface 32a facing each other are formed, for example, slightly tapered from the top to the bottom, and the floor panel 7 is fitted from above into the space between the inner surface 12a and the outer surface 32a.

The floor panel 7 is composed of a double-wall panel, i.e., a panel with a sealed hollow layer formed between opposing inner and outer walls. Figure 3 is a perspective view showing a double-wall panel 40 that constitutes the floor panel 7.

As shown in Figures 2 and 3, the double-walled panel 40 is a hollow panel that is flat in the vertical direction, has a constant thickness, and is elongated in the front-to-rear direction and has a rectangular shape in plan view. The double-walled panel 40 has an outer wall 42, an inner wall 43, a peripheral wall 44, and a partition wall 45. Each of the walls 42 to 45 is made of a rigid plate member with a constant thickness, and is formed, for example, from metals such as aluminum, magnesium, iron, etc., thermosetting resins such as polyester resins, thermoplastic resins such as polypropylene, or fiber-reinforced resins such as CFRP or GFRP.

Of the double-wall panel 40, the outer wall 42 is the part that forms the wall surface (lower surface) of the floor panel 7 facing the outside of the vehicle, and the inner wall 43 is the part that forms the wall surface (upper surface) of the floor panel 7 facing the inside of the vehicle, and these outer wall 42 and inner wall 43 are arranged parallel to each other.

The peripheral wall 44 is a portion that forms the outer peripheral wall surface of the floor panel 7. In this example, the peripheral wall 44 is integrally formed on the peripheral portion of the outer wall 42. In other words, the outer wall 42 and the peripheral wall 44 are integrally formed to form a box shape that opens upward. The inner wall 43 is joined to the peripheral wall 44, thereby forming a hollow layer 50 that is sealed by the outer wall 42, the inner wall 43, and the peripheral wall 44. The peripheral wall 44 may be integrally formed on the peripheral portion of the inner wall 43, or may be formed separately from the outer wall 42 and the inner wall 43 and joined to the outer wall 42 and the inner wall 43.

The partition wall 45 is a reinforcing member for the double-wall panel 40, interposed between the outer wall 42 and the inner wall 43. The provision of the partition wall 45 ensures the rigidity of the double-wall panel 40.

As shown in FIG. 3, the partition 45 includes a first partition 46 that extends linearly in the front-rear direction, and two second partitions 47 that intersect the first partition 46 in a direction perpendicular to the first partition 46. The first partition 46 is disposed in the center of the outer wall 42 (inner wall 43) in the left-right direction, and the second partitions 47 are disposed at positions that divide the outer wall 42 (inner wall 43) into three equal parts in the front-rear direction. The lower surfaces of the first and second partitions 46, 47 are joined to the outer wall 42, and the upper surfaces are joined to the inner wall 43. In addition, both longitudinal end faces of the first and second partitions 46, 47 are joined to the peripheral wall 44. The joining means used is welding, fusion, adhesion, or other means suitable for the material of each wall 42 to 45.

As a result, the hollow layer 50 is divided into six areas S that have the same rectangular shape in a plan view and the same volume. In other words, the partitions 45 divide the hollow layer 50 into six equal parts.

As shown in Figures 3 and 4, the first partition 46 is provided with a plurality of communication sections 48 that connect adjacent areas S across the first partition 46. Similarly, the second partition 47 is formed with a plurality of communication sections 48 that connect adjacent areas S across the second partition 47. This allows all areas S in the double-wall panel 40 to be connected.

The communication section 48 is a long, narrow gate-shaped cutout formed along the longitudinal direction of the lower (outer wall 42 side) ends of the first and second partition walls 46, 47. This forms a slit-like gap between the first and second partition walls 46, 47 and the outer wall 42, and adjacent areas S communicate with each other through the slit-like gap.

As described above, the double-wall panel 40 has a structure in which the hollow layer 50 is divided into six areas S by the partition walls 45, and adjacent areas S are connected to each other by providing communication sections 48 in the partition walls 45. As will be explained next, this type of double-wall panel 40 has a structure that achieves both high levels of panel rigidity and sound insulation, and can be said to be a structure suitable for the floor panel 7.

[Panel rigidity and sound insulation]
Fig. 5 shows the results of a comparison based on CAE (Computer-aided Engineering) analysis of the rigidity (torsional rigidity) and transmission loss of multiple models of a rectangular double-wall panel 40 in plan view, each of which has a different divided structure of the hollow layer 50. In Fig. 5, the horizontal axis indicates the torsional rigidity and the vertical axis indicates the transmission loss, each of which is a value per unit mass. Figs. 6(a) to (d) are schematic plan views showing some of the multiple models (only the partition wall 45 is labeled).

Model N0 in Figure 5 is a double-wall panel without partitions 45. In the figure, the torsional rigidity and transmission loss values of this model N0 are both set to "100."

Models N1 and N2 are double-walled panels in which the hollow layer is divided into four equal parts by vertical and horizontal partition walls 45 that are perpendicular to each other, as shown in FIG. 6(a). Models N3 and N4 are double-walled panels in which the hollow layer is divided into four equal parts by diagonal partition walls 45, as shown in FIG. 6(b). Models N5 and N6 are double-walled panels 40 in which the hollow layer is divided into six equal parts by vertical and horizontal partition walls 45 that are perpendicular to each other, and models N7 and N8 are double-walled panels 40 in which the hollow layer is divided into eight equal parts by vertical and horizontal partition walls 45 that are perpendicular to each other, as shown in FIG. 6(c). Model N9 is a double-walled panel 40 in which the hollow layer is divided into 32 equal parts by vertical and horizontal partition walls 45 that are perpendicular to each other, as shown in FIG. 6(d). Note that "divided equally" here means that the hollow layer is divided into multiple areas that have the same area in a plan view. However, the placement of the partitions 45 is not limited to a perfectly equal position, and can be changed as appropriate, taking into account the rigidity of the surrounding structure.

Of these models, N1, N3, N5, and N7 are models in which the partition 45 does not have a communication section 48, and N2, N4, N6, and N8 are models in which the partition 45 has a communication section 48. Note that the straight line L in the figure shows a linear approximation of the values of all the models.

As shown in Figure 5, model N0, which does not have a partition 45, has the largest transmission loss, i.e., the highest sound insulation. This is because most of the acoustic energy is transmitted through the air, maximizing the sound insulation effect of the double-wall panel. On the other hand, since there is no reinforcement by the partition 45, model N0 has the lowest torsional rigidity.

Conversely, in model N9, in which the hollow layer is divided into 32 equal parts by the partitions 45, the reinforcing effect of the partitions 45 is high and the torsional rigidity is the highest. However, because most of the incident acoustic energy is transmitted through the partitions 45, the reduction in transmission loss due to air transmission is large, and sound insulation is the lowest.

The values of the torsional rigidity and transmission loss of the models N1 to N8 other than the models N0 and N9 are between those of the models N0 and N9. The transmission loss of the models N2, N4, N6, and N8 in which the communication portion 48 is provided in the partition 45 is relatively increased compared to the models N1, N3, N5, and N7 in which the communication portion 48 is not provided. This is thought to be due to the fact that the incidence of acoustic energy from the outer wall to the partition 45 is restricted by the communication portion 48 (notch), suppressing the propagation of acoustic energy through the partition 45, and that the adjacent areas S are connected to each other, increasing the opportunity for the acoustic energy to propagate through the air compared to when the communication portion 48 is not provided. And, among the models N1 to N8, the models N3, N4, N6, N7, and N8 in particular are all in the region above the linear approximation line L, so it can be said that all of them have a high level of both torsional rigidity and transmission loss.

Based on the above findings, in this example, the structure of model N6, which has a particularly good balance between torsional rigidity and transmission loss, is applied as the double-wall panel 40 that constitutes the floor panel 7, out of models N3, N4, N6, N7, and N8, which all have high levels of both. That is, as already described, the double-wall panel 40 that constitutes the floor panel 7 is divided into six areas S that have the same rectangular shape in plan view and the same volume, and further, adjacent areas S are connected to each other by providing communication sections 48 in the partitions 45.

[Effects, etc.]
As described above, a vehicle equipped with the floor panel 7 as described above achieves a high level of both rigidity and sound transmission loss (sound insulation) in the double-wall panel 40 that constitutes the floor panel 7. It can therefore be said that it is possible to achieve a high level of both vehicle rigidity and quietness within the passenger compartment 2.

In particular, the double-wall panel 40 that constitutes the floor panel 7 has partition walls 45 that divide the hollow layer 50 equally into six areas S, ensuring uniform rigidity and sound insulation throughout the entire floor panel 7.

In this case, the partition 45 is made up of the first partition 46 and the second partition 47 that extend linearly, so the partition 45 can be as short as possible. Therefore, compared to when the partition 45 is curved or bent, there is an advantage in that the propagation of acoustic energy from the outer wall 42 to the partition 45 is more suppressed, in other words, the decrease in transmission loss is suppressed, contributing to improved sound insulation.

In addition, in the double-wall panel 40, the partition 45 is provided with a communication section 48, which, as described above, is a long, narrow gate-shaped notch formed along the longitudinal direction of the lower end (the outer wall 42 side) of the partition 45 (first partition 46, second partition 47). With this structure, the communication section 48 (notch) limits the incident path of acoustic energy from the outer wall 42 to the inner wall 43, so that the propagation of acoustic energy from the outer wall 42 to the inner wall 43 via the partition 45 is effectively suppressed. Therefore, the propagation of acoustic energy from the outer wall 42 to the partition 45 can be effectively suppressed without significantly reducing the reinforcing effect of the double-wall panel 40 by the partition 45, i.e., sound insulation can be effectively improved.

[Modifications, etc.]
The structure of the floor panel 7 in the embodiment described above is an example of a preferred embodiment of the panel structure of the vehicle according to the present invention, and the specific configuration can be appropriately changed without departing from the gist of the present invention. For example, the following configurations can be adopted.

(1) In the embodiment, the double-wall panel 40 has a structure in which the hollow layer 50 is divided into six equal parts by the partition walls 45. However, as described above, even in the case of a structure in which the hollow layer 50 is divided into four or eight equal parts (models N1 to N4, N7, and N8 in FIG. 5), it is possible to achieve a relatively high level of both torsional rigidity and transmission loss. Furthermore, based on the knowledge in FIG. 5, it is predicted that it is possible to achieve torsional rigidity and transmission loss equivalent to or close to those of the models N1 to N8, as long as the hollow layer 50 is divided into any number of areas S, not limited to equal divisions, from 4 to 8. Therefore, the double-wall panel 40 only needs to have partition walls 45 that divide the hollow layer 50 into any number of areas S, from 4 to 8.

(2) In the double-wall panel 40 of the embodiment, the communication portion 48 of the partition wall 45 is, as described above, a long and narrow gate-shaped notch formed along the longitudinal direction of the lower end (the outer wall 42 side) of the partition wall 45 (first partition wall 46, second partition wall 47). However, the communication portion 48 may also be, for example, a slit-shaped opening (a through hole penetrating the partition wall 45 in its thickness direction) formed in the partition wall 45 (first partition wall 46, second partition wall 47) and elongated in the longitudinal direction of the partition wall 45. In this case, although only the communication portion 48 consisting of an opening may be provided, it is preferable to use both the communication portion 48 consisting of a notch and the communication portion consisting of an opening.

For example, Figures 7 and 8 show an example of a structure (first partition 46) that combines a communication portion 48 (referred to as a first communication portion 48) consisting of a notch and a communication portion 49 (referred to as a second communication portion 49) consisting of an opening.

In the example of FIG. 7, the second communication portion 49 is formed at a position closer to the inner wall 43 than the first communication portion 48, and the first communication portion 48 and the second communication portion 49 are arranged in a staggered arrangement with a shifted arrangement pitch in the extension direction (front-rear direction) of the first partition wall 46. The example of FIG. 8 is a modified example of the example of FIG. 7, and in this example, the first communication portion 48 and the second communication portion 49 have an overlapping area Ar in the extension direction. In this way, the structure that uses the first communication portion 48 consisting of a cutout portion and the second communication portion 49 consisting of an opening portion in combination makes it possible to suppress the propagation of acoustic energy from the outer wall 42 to the inner wall 43 through the partition wall 45 without significantly reducing the reinforcing effect of the double-wall panel 40 by the partition wall 45. In particular, in the example of FIG. 8, as shown by the dashed arrow in the figure, the propagation path of the acoustic energy is bent, making it difficult for the acoustic energy to propagate from the outer wall 42 to the inner wall 43, which can be said to further contribute to improving sound insulation.

The specific form of the communication section 48 (49) is not limited to the embodiment described above, but can be appropriately selected so as to more effectively suppress the propagation of acoustic energy through the partition wall section 45.

(3) In the embodiment, the partition 45 is made of a rigid body (a plate member having rigidity), but the partition 45 may be made of a combination of a rigid body and a viscoelastic member. Figure 9 shows the structure of such a double-walled panel 40, with Figure 9(a) being a cross-sectional view of a main part along the vehicle width direction, and Figure 9(b) being a cross-sectional view along line IX-IX of Figure 9(a), each showing the double-walled panel 40.

As shown in Figures 9(a) and (b), the first partition 46 is composed of a partition body 46a made of a rigid body and a viscoelastic member 46b interposed between the partition body 46a and the outer wall 42.

The bulkhead body 46a has a T-shaped cross section, with a bulkhead main portion 461 extending from the underside of the inner wall 43 toward the outer wall 42, and flange portions 462 extending from the tip of the bulkhead main portion 461 along the outer wall 42 on both sides in the vehicle width direction.

The viscoelastic member 46b may be, for example, a rubber material such as styrene-butadiene rubber or an elastomer resin such as polyester resin. The viscoelastic member 46b is interposed between the flange portion 462 and the outer wall 42. In detail, as shown in FIG. 9(b), the viscoelastic members 46b are provided at a plurality of positions spaced apart from each other along the longitudinal direction of the partition body 46a (the left-right direction in FIG. 9(b)). This forms the communication portion 48 between adjacent viscoelastic members 46b. Although not shown, the second partition 47 is configured in the same manner as the first partition 46.

With the double-wall panel 40 shown in Figures 9(a) and (b), of the acoustic energy incident on the outer wall 42, a portion of the acoustic energy (vibration energy) that propagates through the viscoelastic member 46b to the inner wall 43 is converted to thermal energy and lost. This makes it difficult for acoustic energy to propagate from the outer wall 42 to the inner wall 43, which contributes to improving sound insulation.

In the structure of FIG. 9, for example, the flange portion 462 of the partition body 46a may be omitted, and the viscoelastic member 46b may be interposed between the end of the partition main portion 461 and the outer wall 42. However, a structure including the flange portion 462 can ensure a larger occupancy area for the viscoelastic member 46b interposed between the partition body 46a and the outer wall 42. This is therefore advantageous in improving the effect of suppressing the propagation of acoustic energy by the energy conversion described above.

Figure 10 shows another example of a double-walled panel 40 in which the partition 45 is constructed by combining a rigid body and a viscoelastic member. Figure 10(a) is a cross-sectional view of a main part of the double-walled panel 40 taken along the vehicle width direction, and Figure 10(b) is a cross-section taken along line X-X in Figure 10(a), showing the double-walled panel 40.

In the example shown in FIG. 10, the first partition 46 is also composed of a partition body 46a made of a rigid body and a viscoelastic member 46b, but the configuration differs from the example in FIG. 9 in the following respects.

The partition body 46a has an inner wall side partition portion 463 that extends (hangs down) from the inner wall 43 toward the outer wall 42, and an outer wall side partition portion 464 that extends (rises) from the outer wall 42 toward the inner wall 43 and faces (opposes) the inner wall side partition portion 463 in the vehicle width direction.

The viscoelastic members 46b are interposed between the inner wall side partition portion 463 and the outer wall side partition portion 464. More specifically, as shown in FIG. 10(b), the viscoelastic members 46b are provided at a plurality of positions spaced apart from each other along the longitudinal direction (left-right direction in FIG. 10(b)) of the partition body 46a (the inner wall side partition portion 463 and the outer wall side partition portion 464). As a result, the communication portion 48 is formed between adjacent viscoelastic members 46b. Although not shown, the second partition 47 is configured similarly to the first partition 46.

The structure shown in Figure 10 can achieve the same effects as the structure shown in Figure 9.

(4) In the embodiment, an example in which the floor panel 7 is constructed from the double-wall panel 40 has been described, but for example, the dash panel 3, rear floor 10, roof panel 24, and front and rear doors not shown in the figure may also be constructed from double-wall panels having a structure similar to the double-wall panel 40 described above. These structures make it possible to ensure high levels of quietness by effectively suppressing the intrusion of noise from outside the vehicle, such as road noise and driving sounds, into the passenger compartment 2 while ensuring the rigidity of the vehicle.

2 Vehicle interior 3 Dash panel 7 Floor panel 8 Tunnel portion 10 Rear floor 12 Side sill 24 Roof panel 30 Main body portion 32 Lateral protrusion portion 40 Double wall panel 42 Outer wall 43 Inner wall 44 Peripheral wall 45 Partition wall 46 First partition wall 47 Second partition wall 48 Communication portion (first communication portion)
49 Second communicating portion 50 Hollow layer S Area

Claims (15)

A vehicle panel structure comprising a double-wall panel having an outer wall and an inner wall opposed to each other in the inside-outside direction of a vehicle, and a sealed hollow layer formed between the outer wall and the inner wall,
a partition wall interposed between the outer wall and the inner wall and dividing the hollow layer into any number of areas from 4 to 8 ;
The partition wall has one or more communication parts formed therein, the communication parts connecting adjacent areas across the partition wall,
the communication portion is a notch portion formed in an end portion of the partition wall on the outer wall side,
the partition wall is formed with a plurality of first communication portions each consisting of the notch portion and arranged at a predetermined interval in the extension direction of the partition wall, and a plurality of second communication portions each consisting of a through hole penetrating the partition wall in its thickness direction and arranged at a predetermined interval in the extension direction at a position closer to the inner wall than the first communication portions,
The vehicle panel structure , wherein the first communication portions and the second communication portions are arranged in a staggered configuration in which the arrangement pitches of the first communication portions and the second communication portions are shifted from each other in the extending direction . The vehicle panel structure according to claim 1,
A vehicle panel structure, wherein the partition divides the hollow layer into any one of four, six, or eight equal areas. The vehicle panel structure according to claim 1 or 2,
A vehicle panel structure characterized in that the partition wall includes a first partition wall extending linearly in a first direction along the outer wall and the inner wall, and a second partition wall extending linearly in a second direction intersecting the first direction and along the outer wall and the inner wall. The vehicle panel structure according to any one of claims 1 to 3 ,
13. A vehicle panel structure, comprising: a partition wall that is formed in a first direction and a second direction, the partition wall extending in a first direction; The vehicle panel structure according to any one of claims 1 to 4 ,
A vehicle panel structure, comprising: the first communication portion and the second communication portion having an overlapping region in the extending direction. A vehicle panel structure comprising a double-wall panel having an outer wall and an inner wall opposed to each other in the inside-outside direction of a vehicle, and a sealed hollow layer formed between the outer wall and the inner wall,
a partition wall interposed between the outer wall and the inner wall and dividing the hollow layer into any number of areas from 4 to 8;
The partition wall has one or more communication parts formed therein, the communication parts connecting adjacent areas across the partition wall,
The partition wall includes a partition wall body and a viscoelastic member interposed between the partition wall body and an outer wall,
a communication portion formed between adjacent viscoelastic members by providing the viscoelastic members at a plurality of mutually spaced positions along the partition body, the communication portion being formed between adjacent viscoelastic members . The vehicle panel structure according to claim 6,
A vehicle panel structure , wherein the partition divides the hollow layer into any one of four, six, or eight equal areas . The vehicle panel structure according to claim 6 or 7,
A vehicle panel structure characterized in that the partition wall includes a first partition wall extending linearly in a first direction along the outer wall and the inner wall, and a second partition wall extending linearly in a second direction intersecting the first direction and along the outer wall and the inner wall . The vehicle panel structure according to any one of claims 6 to 8 ,
13. A vehicle panel structure, comprising : a partition wall that is formed in a first direction and a second direction, the partition wall extending in a first direction ; The vehicle panel structure according to any one of claims 6 to 9,
the partition wall body has a T-shaped cross section including a partition wall main portion extending from the inner wall toward the outer wall and flange portions extending from a tip of the partition wall along the outer wall on both sides,
A vehicle panel structure, comprising: a flange portion and an outer wall, the flange portion being disposed between the flange portion and the outer wall; A vehicle panel structure comprising a double-wall panel having an outer wall and an inner wall opposed to each other in the inside-outside direction of a vehicle, and a sealed hollow layer formed between the outer wall and the inner wall,
a partition wall interposed between the outer wall and the inner wall and dividing the hollow layer into any number of areas from 4 to 8;
The partition wall has one or more communication parts formed therein, the communication parts connecting adjacent areas across the partition wall,
the partition wall is composed of an inner wall-side partition wall portion extending from the inner wall toward the outer wall, an outer wall-side partition wall portion extending from the outer wall toward the inner wall and facing the inner wall-side partition wall portion, and a viscoelastic member interposed between the inner wall-side partition wall portion and the outer wall-side partition wall portion,
A vehicle panel structure, characterized in that the viscoelastic members are provided at a plurality of mutually spaced positions along the inner wall side partition portion and the outer wall side partition portion, thereby forming the communication portions between adjacent viscoelastic members . The vehicle panel structure according to claim 11 ,
A vehicle panel structure , wherein the partition divides the hollow layer into any one of four, six, or eight equal areas . The vehicle panel structure according to claim 11 or 12,
A vehicle panel structure characterized in that the partition wall includes a first partition wall extending linearly in a first direction along the outer wall and the inner wall, and a second partition wall extending linearly in a second direction intersecting the first direction and along the outer wall and the inner wall. The vehicle panel structure according to any one of claims 11 to 13,
13. A vehicle panel structure, comprising: a partition wall that is formed in a first direction and a second direction, the partition wall extending in a first direction; The vehicle panel structure according to any one of claims 1 to 14,
The panel structure of a vehicle is any one of a floor panel, a dash panel, a roof panel, and a door panel.