Vehicle under structure

Abstract

A vehicle lower structure in which a battery is mounted is provided with a first cushion disposed near the center of a vehicle so as to be sandwiched between the battery and a floor panel in the vertical direction of the vehicle.

Description

Technical Field

[0001] The present invention relates to a vehicle underbody structure. Background Art

[0002] In a vehicle in which a battery is mounted on the floor, a vehicle underbody structure mainly for protecting the battery has been proposed. For example, in order to reduce the collision load on the battery in the case of a collision from the side of the vehicle, there is a structure in which components are arranged so as to surround the side of the battery. In addition, there is a structure in which a buffer member is provided on the floor to protect the battery from the load applied during a collision.

[0003] Japanese Unexamined Patent Application Publication No. 2021-123227 discloses a vehicle-mounted structure of a battery pack disposed on the floor of a vehicle. In this vehicle-mounted structure, the battery pack includes a battery cell, a battery pack case in which the battery cell is disposed, and a buffer member disposed between the battery cell and the battery pack case. In this structure, the buffer member is configured to be sandwiched between the battery cell and the floor or between the battery cell and the battery pack case by fixing the battery pack case to the floor. Therefore, according to this vehicle-mounted structure, the battery cell can be reliably fixed with a simple structure while ensuring high reliability. Summary of the Invention

[0004] Here, in a vehicle equipped with a battery, sometimes the installation of a reinforcing member for improving the strength of the vehicle body near the center of the floor is abolished. In this case, during the vehicle running on the road surface, due to the vibration of the vicinity of the center of the floor (that is, the vicinity where the center tunnel and the floor cross member are arranged), the amount of deformation of the floor in the up and down directions becomes large. As a result, the riding comfort of the vehicle sometimes deteriorates. Therefore, it is desired to reduce the vibration transmitted from the road surface during running and improve the riding comfort. However, the buffer member used for the purpose of protecting the battery as described above has low rigidity and cannot suppress the up and down deformation of the floor.

[0005] Therefore, in the present specification, a vehicle underbody structure is realized in which a buffer member is provided near the center of the floor and between the battery and the floor panel, thereby protecting the battery and increasing the rigidity of the vicinity of the center of the floor to suppress the vibration of the vehicle body during vehicle running.

[0006] The vehicle underbody structure according to the embodiment of the present disclosure is equipped with a battery, and the vehicle underbody structure includes a first buffer member configured to be sandwiched between the battery and the floor panel in the vehicle up and down direction near the center of the vehicle.

[0007] According to the above embodiment, the vibration of the battery and the floor panel is suppressed by the first buffer member, so that the rigidity of the floor and its periphery near the center of the vehicle can be increased.

[0008] Alternatively, the first buffer member may be disposed near the floor passage of the floor.

[0009] According to the above structure, the rigidity near the floor passage can be particularly improved.

[0010] Alternatively, the vehicle underbody structure may further include a second buffer member, which is disposed near the center of the floor panel provided between the floor passage and the vehicle-mounted portion of the battery in the vehicle width direction and at a position outside the first buffer member.

[0011] The first buffer member may also be configured to have a higher rigidity than the second buffer member.

[0012] According to the above structure, by ensuring the rigidity of the first buffer member and setting the rigidity of the second buffer member lower than that of the first buffer member, loosening of the fastening portion between the battery and the vehicle in the vehicle-mounted portion of the battery near the second buffer member can be suppressed.

[0013] According to the vehicle underbody structure disclosed in this specification, the rigidity of the floor and its periphery near the center of the vehicle can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The features, advantages, technology and industrial significance of the embodiments of the present invention are described as follows with reference to the accompanying drawings, in which the same reference numerals denote the same elements.

[0015] Figure 1 is a top view schematically showing the floor of a vehicle to which the vehicle underbody structure of the embodiment is applied.

[0016] Figure 2 is showing Figure 1 the inertia of each frequency in the vehicle underbody structure of.

[0017] Figure 3 is showing Figure 1 the vibration level of each frequency in the vehicle underbody structure of. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Hereinafter, the vehicle underbody structure will be described with reference to the accompanying drawings. In addition, in Figure 1 ,"Fr", "Up" and "Rh" respectively represent the front, upper and right sides of the vehicle.

[0019] Figure 1 is a top view schematically showing the floor of a vehicle to which the vehicle underbody structure of the embodiment is applied. As Figure 1As shown, the vehicle lower structure 10 is the structure of a vehicle equipped with a storage battery 12. A first buffer member 14 and a second buffer member 16 are arranged on the upper surface of the storage battery 12 in the vehicle up-and-down direction. In addition, the storage battery 12 is mounted on the vehicle at a bolt fastening portion 18. In Figure 1 , the first buffer member 14 is indicated by a thick ink portion. In addition, the bolt fastening portion 18 is indicated by a blackened ellipse.

[0020] Figure 1 The figure below the thick arrow shown is a plan view showing the floor 20 of the vehicle. More specifically, the figure below the thick arrow is a view showing the structure in which the floor 20, its lower part, and the surrounding components are overlapped from above the storage battery 12 (represented by the figure above the thick arrow). In this figure, since the storage battery 12 is arranged below the floor 20, most of it is blocked by the floor 20 when viewed from above. Therefore, in this figure, only the two end portions of the storage battery 12 in the vehicle width direction, that is, the portions not blocked by the floor 20, appear.

[0021] As Figure 1 shown, the floor 20 has a floor panel 22, a floor tunnel 24, and a center floor cross member 26. In addition, although it will be described later, in the floor panel 22, the floor panel on which the second buffer member 16 is installed is indicated by a light black portion for distinction from others. In addition, when viewed from above, since the first buffer member 14 and the second buffer member 16 arranged below the floor 20 are hidden, they are represented as hidden lines by dashed lines.

[0022] Next, with reference to Figure 1 , the structure of the vehicle lower structure 10 will be further described. As described above, the vehicle lower structure 10 is composed of a storage battery 12, a first buffer member 14, a second buffer member 16, and a floor panel 22 in sequence from below in the vehicle up-and-down direction. That is, the first buffer member 14 and the second buffer member 16 are arranged in such a way that they are sandwiched between the storage battery 12 and the floor panel 22 in the up-and-down direction. In addition, the floor panel 22 is configured to be supported from below by the storage battery 12 on which the first buffer member 14 and the second buffer member 16 are installed. In addition, the storage battery 12 is supported on the vehicle body by other structural components.

[0023] In addition, as Figure 1As shown, in the vehicle underbody structure 10, a plurality of first buffer members 14 and second buffer members 16 are respectively provided. In this example, three first buffer members 14 and three second buffer members 16 are provided on each of the left and right sides, for a total of six each, but the number is not limited to this. In addition, the first buffer members 14 and the second buffer members 16 are not limited to being provided in plurality on the left and right respectively. For example, it may also be a structure in which one first buffer member 14 is provided on each of the left and right sides near both sides of the floor tunnel 24. In this case, the first buffer member 14 may not be Figure 1 the small and rectangular shape as shown. For example, the first buffer member 14 may also be a substantially rectangular shape with the longitudinal direction in the vehicle front-rear direction as the long side. However, in the case where the first buffer member extends along the floor tunnel 24 and is a large shape compared to the first buffer member 14 in this example, problems such as becoming an obstacle to the installation of other components around the floor 20 and becoming a main cause of an increase in mass may occur. Therefore, in this example, considering the assembly workability, mass, cost, etc. comprehensively, a plurality of first buffer members 14 and second buffer members 16 are provided on each of the left and right sides.

[0024] Next, the first buffer member 14 will be further described. The first buffer member 14 is arranged near the center of the vehicle in such a manner that it is sandwiched between the battery 12 and the floor panel 22 in the up-down direction. More specifically, the first buffer member 14 is provided near the floor tunnel 24. As described above, generally, in a vehicle equipped with a battery, sometimes a reinforcing member is not provided near the center of the floor. The reason is that, for example, by omitting the reinforcing member, the lower end position of the battery can be made relatively high, etc. Therefore, the rigidity near the center of the floor is reduced. Specifically, Figure 1 the rigidity of the portion A (hereinafter referred to as "near the center A") surrounded by the double-dot dash rounded rectangle in the figure is reduced. The battery 12 and the floor panel 22 have different natural frequencies. Therefore, in the case where no component such as a reinforcing member for suppressing the vibration of the battery 12 and the floor panel 22 is provided, especially for the floor panel 22, the vibration during vehicle travel cannot be suppressed. As a result, the vibration of the floor panel 22 such as near the center A becomes large, and the riding comfort of the passengers in the vehicle sometimes deteriorates. Therefore, in this example, by arranging the first buffer member 14 near the center A of the floor 20, the up-down vibration (in other words, the deformation amount in the up-down direction) of the floor 20 at near the center A is suppressed.

[0025] The first buffer member 14 in this example supports the floor panel 22 together with the storage battery 12 to move in the vertical direction due to vibrations during driving, and functions to suppress the vibrations that affect each other between the floor panel 22 and the storage battery 12. Therefore, the first buffer member 14 is set to be able to suppress the vibrations of the floor panel 22 and have sufficient rigidity to support the floor panel 22 together with the storage battery 12. That is, the first buffer member 14 is different from the buffer members with reduced rigidity used for the purpose of protecting the storage battery in the past. Moreover, the first buffer member 14 is set to have a higher rigidity than the rigidity required for the original function as a buffer member between the storage battery 12 and the floor panel 22 (for example, the image of reinforced sponge).

[0026] Next, the second buffer member 16 will be further described. As described above, the second buffer member 16 is provided on the upper surface of the storage battery 12 and on the lower surface of the floor panel 22 indicated by the light ink portion in Figure 1 . That is, the second buffer member 16 is arranged in the same manner as the first buffer member 14 so as to be sandwiched between the storage battery 12 and the floor panel 22 in the vertical direction. In addition, the second buffer member 16 is provided near the center of the floor panel 22 indicated by the light ink portion and at a position more outward than the first buffer member 14. Therefore, the second buffer member 16 is provided at a portion closer to the bolt fastening portion 18 than the first buffer member 14. At this time, if the rigidity of the second buffer member 16 is set to be the same as that of the first buffer member 14 with increased rigidity as described above, an adverse situation may occur at the bolt fastening portion 18. That is, when the rigidity of the second buffer member 16 is high, the following problem will occur: the bolts are not fastened at the bolt fastening portion 18 near both ends of the storage battery 12 and at the portion where it is mounted to the vehicle. Therefore, the rigidity of the second buffer member 16 is set lower than that of the first buffer member 14. According to this structure, it is possible to avoid the state where the storage battery 12 is firmly mounted to the vehicle at the second buffer member 16 portion (that is, the image where the storage battery 12 is fixed by the second buffer member 16). As a result, it is possible to suppress loosening of the fastening at the fastening portion between the storage battery 12 and the vehicle (that is, the bolt fastening portion 18).

[0027] Through the above-described vehicle underbody structure, it is verified how much different the vertical vibrations of the floor 20 are compared with the past, and an example is shown in Figure 2 , Figure 3 . Here, Figure 2 is a graph showing the inertia of each frequency in the vehicle underbody structure of Figure 1 , and Figure 3 is a graph showing the vibration level of each frequency in the vehicle underbody structure of Figure 1 .

[0028] More specifically, Figure 2The graph shown represents the up-and-down vibration of the floor 20 in the vicinity of the floor passage 24 and a part of the center floor cross member 26. In Figure 2 , the inertia of each frequency of the vehicle underbody structure according to the embodiment is represented by the solid line a. In addition, in Figure 2 , the inertia of each frequency of the existing vehicle underbody structure (i.e., the structure without the first buffer member 14 and the second buffer member 16 installed in the embodiment) is represented by the semi-dashed line b. In addition, inertia is one of the transfer functions in the vibration field, which is the ratio of the force input to an object to the acceleration that can be generated thereby. Various information such as the resonance frequency and the decay rate can be obtained from such transfer functions as inertia. Here, from the comparison between the solid line a and the semi-dashed line b in Figure 2 , it can be seen that within the range indicated by the light ink portion, the inertia is quite different between the vehicle underbody structure according to the embodiment and the existing vehicle underbody structure. And when calculating the rigidity based on the result of inertia, compared with the conventional vehicle underbody structure, it is obtained that the rigidity around the center floor cross member 26 in the vehicle underbody structure of the embodiment is increased to about three times.

[0029] Next, regarding the up-and-down vibration of the floor 20 in the vehicle underbody structure of the embodiment, verification was also carried out at positions other than near the rear end of the floor passage 24 such as the center floor cross member 26. Figure 3 The graph shown represents the up-and-down vibration of a traveling vehicle in the front side of the floor 20, more specifically, near the front side of the seat track (not shown) of the front seat. In Figure 3 , the vibration level of each frequency of the vehicle underbody structure of the embodiment is represented by the solid line c. In addition, in Figure 3 , the vibration level of each frequency of the existing vehicle underbody structure (i.e., the structure without the first buffer member 14 and the second buffer member 16 installed in the embodiment) is represented by the semi-dashed line d. From the comparison between the solid line c and the semi-dashed line d in Figure 3 , it can be seen that especially at the position indicated by the black arrow, the vibration level is quite different between the vehicle underbody structure of the embodiment and the conventional vehicle underbody structure. That is, in this verification, compared with the conventional vehicle underbody structure, it is obtained that the vibration level on the front side of the floor 20 in the vehicle underbody structure of the embodiment is significantly reduced.

[0030] In addition, the description so far is an example. In the vehicle underbody structure disclosed in this specification, it is sufficient that the structure includes a first buffer member disposed near the center of the vehicle in a manner sandwiched between the battery and the floor panel in the vehicle vertical direction. Therefore, other structures can also be appropriately changed. For example, the shapes, sizes, numbers, and materials of the first buffer member and the second buffer member are not particularly limited. As an example, it is also possible to set their rigidities to be different by using different materials for the first buffer member and the second buffer member. In addition, as another example, the first buffer member and the second buffer member can be formed of the same material, and the hardness can be changed by making their respective compression amounts (i.e., the degrees of compression) different. Furthermore, foamed resins with different degrees of foaming can also be used.

Claims

1. A vehicle underbody structure is equipped with a storage battery. The vehicle underbody structure includes a first buffer member, which is arranged near the center of the vehicle in such a manner that it is sandwiched between the storage battery and the floor panel in the vehicle's vertical direction.

2. The vehicle underbody structure according to claim 1, wherein the first buffer member is provided near the floor tunnel of the floor.

3. The vehicle underbody structure according to claim 2, wherein the vehicle underbody structure further includes a second buffer member, which is arranged near the center of the floor panel provided between the floor tunnel and the mounting portion of the storage battery to the vehicle in the vehicle width direction and at a position outside the first buffer member. The first buffer member is configured to have a higher rigidity than the second buffer member.

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