Vehicle undercarriage

Abstract

To provide a lower part structure for a vehicle that is able to prevent vibration energy, caused by a relay portion of a battery unit, from being transmitted into a vehicle cabin, without increasing mass.SOLUTION: A lower part structure for a vehicle includes a connecting member 60 connecting a first battery unit 21 and a second battery unit 22. The connecting member 60 includes first fixing portions 61F, 61R fixed to the first battery unit 21 so as to be separate from each other in a vehicle longitudinal direction, and a second fixing portion 62 fixed to the second battery 22. A rear end of the first fixing portion is located at a vehicle rear side from the second fixing portion 62. The connecting member 60 includes a rigidity reducing portion 65 that reduces rigidity against a load in the longitudinal direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle underbody structure in which a battery unit is mounted under a floor. [Background technology]

[0002] 2. Description of the Related Art A vehicle underbody structure is known in the art that has a battery unit disposed under a floor and is provided with a relay unit that is fixed to the battery unit and switches an electric circuit of the vehicle. When the battery unit is quickly charged, the contacts of a relay section that switches an electrical circuit in response to ON / OFF switching, causing the floor panel to resonate through the battery unit, resulting in a phenomenon in which sound is transmitted into the vehicle cabin.

[0003] Specifically, when the relay unit is electrically turned ON or OFF, a physical relay sound is generated. When the movable contact inside the relay that constitutes the relay unit collides and comes into contact with the fixed contact, a hitting sound is generated as a relay sound, and this relay sound is input to the vehicle body via the junction box that connects the relay unit and the battery unit, the rubber mount, the battery unit, and the part that fixes the battery unit to the vehicle body, causing the floor panel to vibrate, and the sound is transmitted into the vehicle cabin.

[0004] When battery units are provided spaced apart on the left and right sides of the tunnel, as in a PHEV (plug-in hybrid electric vehicle), a resonant mode occurs in which the left and right battery units move back and forth alternately with a phase delay, with the relay section acting as a vibration source.

[0005] If the left and right battery units are rigidly connected in the vehicle width direction in order to suppress this resonance mode (see Patent Document 1), the left and right battery units will simply move in phase, and vibration cannot be suppressed.

[0006] One possible solution to this problem is to provide a reinforcing member between the vehicle body and the battery unit to suppress vibration. However, this would result in a new problem of increased mass. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2020-45069 A Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide a vehicle underbody structure that can suppress the transmission of vibration energy caused by the relay portion of a battery unit into the vehicle cabin without increasing the mass. [Means for solving the problem]

[0009] The vehicle understructure according to the present invention includes a side sill extending in a front-rear direction of the vehicle on an outer side in a vehicle width direction, a first battery unit and a second battery unit provided adjacent to an inner side in the vehicle width direction of the side sill and spaced apart in the vehicle width direction below a floor panel, and a battery unit fixed to at least one of the first battery unit and the second battery unit. R, The battery battery assembly includes a relay unit that switches an electrical circuit of the vehicle, and a connecting member that connects between the first battery unit and the second battery unit, the connecting member having a first fixing portion that is fixed to the first battery unit and spaced apart in the fore-and-aft direction of the vehicle, and a second fixing portion that is fixed to the second battery unit, the rear end of the first fixing portion being located rearward of the second fixing portion, and the connecting member having a rigidity reduction portion that reduces rigidity against fore-and-aft loads. The above-mentioned connecting member is preferably made of a material having high tensile strength.

[0010] According to the above configuration, the rear end of the first fixing portion and the second fixing portion are offset in the vehicle front-rear direction, resulting in a connecting structure in which they are spaced apart in the diagonal front-rear direction. This diagonal connection results in a structure that is less likely to deform when subjected to input in the vehicle front-rear direction. In other words, the rigidity of the connecting member in the vehicle front-rear direction can be improved.

[0011] On the other hand, the reduced rigidity portion reduces the rigidity of the connecting member against a load in the front-rear direction. This allows the connecting member to have an element that increases rigidity and an element that decreases rigidity, and makes it possible to control the resonance mode so as to maintain the opposite phase of the vibration form.

[0012] Therefore, by controlling the rigidity of the connecting member in the fore-and-aft direction of the vehicle so that the first and second battery units are in an opposite-phase resonant mode with the same vibration level, the left and right floor panels are vibrated in opposite phases, thereby canceling out noise generated inside the vehicle cabin. In short, it is possible to suppress the vibration energy caused by the relay portion of the battery unit from being transmitted to the interior of the vehicle cabin without increasing the mass.

[0013] The reason why the connecting member needs elements that increase rigidity and elements that decrease rigidity is as follows. That is, if the rigidity of the connecting member is increased to a certain extent, the phase shift of the vibration is reduced and the vibration energy is uniformed. As a result, the floor panel can be vibrated in opposite phase, and the sound generated in the vehicle cabin can be canceled. On the other hand, if the rigidity of the connecting member is increased too much, the phase shift is eliminated, and the first battery unit and the second battery unit move together in phase, worsening the vibration of the floor panel. For this reason, the connecting member needs elements that increase rigidity and elements that decrease rigidity.

[0014] In addition, the deformation of the connecting member caused by the relay section as the vibration source is shear deformation, but the direction of the shear stress acting on the connecting member caused by the relay section as the vibration source is in the fore-and-aft direction of the vehicle, and therefore it is controlled by the rigidity in the fore-and-aft direction of the vehicle.

[0015] In one embodiment of the present invention, the connecting member has a widthwise connecting portion that connects the first battery unit and the second battery unit in the vehicle width direction, and a diagonal connecting portion that diagonally connects the front of one battery unit and the rear of the other battery unit. According to the above-mentioned configuration, vibration energy can be most efficiently transmitted with respect to shear deformation.

[0016] In one embodiment of the present invention, the first fixing portion is fixed to the first battery unit by a plurality of first fixing members, The above multiple No. 1 The fixing member has a first bead extending in the front-rear direction of the vehicle adjacent to the inside in the vehicle width direction of the rear part of the first fixing portion that is provided with a space in the front-rear direction of the vehicle.

[0017] The above configuration has the following advantages. In other words, if the first bead does not exist, multiple No. 1 The front end of the fixing member No. 1 Although stress is concentrated on the fixing member, by providing the first bead, the stress can be dispersed to the rear end side, and the strength reliability of the connecting member can be ensured.

[0018] In one embodiment of the present invention, the second fixing portion is fixed to the second battery unit by a plurality of second fixing members, The above multiple Second The fixing member has a second bead extending in the front-rear direction of the vehicle adjacent to the inner side in the vehicle width direction of the second fixing portion provided at a distance in the front-rear direction of the vehicle.

[0019] The above configuration has the following advantages. In other words, if the second bead does not exist, multiple Second Rear end of the fixing member side of Second Although stress is concentrated on the fixing member, by providing the second bead, the stress can be dispersed to the front end side, and the strength reliability of the connecting member can be ensured.

[0020] In one embodiment of the present invention, the reduced rigidity portion is formed by a plurality of beads extending in the vehicle width direction. According to the above configuration, the rigidity at a specific portion of the connecting member can be reduced by the ridge line in the vehicle width direction of the bead, thereby ensuring the deformation freedom of the connecting member, so that the rigidity reduction portion can be formed with a simple structure. Effect of the Invention

[0021] According to the present invention, it is possible to suppress the vibration energy caused by the relay portion of the battery unit from being transmitted to the inside of the vehicle cabin without increasing the mass. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a bottom view of a main part of a vehicle equipped with a vehicle undercarriage of the present invention; [Diagram 2] FIG. 2 is a perspective view showing the structure of FIG. 1 as viewed from below the vehicle. [Diagram 3] Cross-sectional view of line AA in Figure 1 [Figure 4] Cross-sectional view of line BB in Figure 1 [Diagram 5] Bottom view of the connecting member [Figure 6] A bottom perspective view of the connecting member [Figure 7] FIG. 7 is a bottom perspective view of the connecting member shown at an angle different from that of FIG. 6; [Figure 8] Cross-sectional view of line DD in Figure 5 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The purpose of suppressing the transmission of vibration energy caused by a relay unit of a battery unit to the inside of a vehicle cabin without increasing mass is achieved by comprising a side sill extending in the front-rear direction of the vehicle on the outer side in the vehicle width direction, a first battery unit and a second battery unit provided adjacent to the inner side in the vehicle width direction of the side sill and spaced apart in the vehicle width direction below the floor panel, and a battery unit fixed to at least one of the first battery unit and the second battery unit. R,The battery battery is realized by a configuration comprising a relay unit which switches the vehicle's electrical circuit, and a connecting member which connects between the first battery unit and the second battery unit, the connecting member comprising a first fixing portion which is spaced apart in the fore-and-aft direction of the vehicle and fixed to the first battery unit, and a second fixing portion which is fixed to the second battery unit, the rear end of the first fixing portion being located rearward of the second fixing portion, and the connecting member comprising a rigidity reducing portion which reduces the rigidity against fore-and-aft loads. EXAMPLES

[0024] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. The drawings show the underbody structure of a vehicle, with FIG. 1 being a bottom view of a key part of the vehicle equipped with the underbody structure, more specifically, a bottom view showing the center pillar and its fore-and-aft position, FIG. 2 being a perspective view showing the structure of FIG. 1 as seen from below the vehicle, FIG. 3 being a cross-sectional view taken along line AA in FIG. 1, and FIG. 4 being a cross-sectional view taken along line BB in FIG. 1.

[0025] 5 is a bottom view of the connecting member, FIG. 6 is a bottom perspective view of the connecting member, FIG. 7 is a bottom perspective view of the connecting member shown at an angle different from that of FIG. 6, and FIG. 8 is a cross-sectional view taken along line DD in FIG.

[0026] In the figure, arrow F indicates the front of the vehicle, arrow R indicates the rear of the vehicle, arrow LE indicates the left outer side in the vehicle width direction, arrow RI indicates the right outer side in the vehicle width direction, and arrow UP indicates the top of the vehicle.

[0027] As shown in Fig. 3, a side sill 1 is provided as a vehicle body strength member extending in the front-rear direction of the vehicle on both the left and right outer sides in the vehicle width direction. This side sill 1 has a side sill closed cross section 4 extending in the front-rear direction of the vehicle by joining and fixing a side sill outer 2 and a side sill inner 3. In this embodiment, a center pillar inner 5 is sandwiched between the side sill outer 2 and the side sill inner 3 at the center pillar installation site.

[0028] As shown in Figs. 2 and 3, the center pillar 6 is a vehicle body strength member having a center pillar closed cross section extending in the vertical direction of the vehicle by joining and fixing an inner center pillar 5 (see Fig. 3) and an outer center pillar 7 together.

[0029] As shown in Fig. 3, a floor panel 8 constituting the floor surface of the vehicle compartment is provided between the side sill inners 3, 3 of a pair of left and right side sills 1, and a tunnel portion 9 is provided in the center in the vehicle width direction of this floor panel 8. This tunnel portion 9 may be formed integrally with the floor panel 8, or a structure in which a separate tunnel portion 9 is attached to the floor panel 8 may be adopted.

[0030] As shown in Figures 3 and 4, tunnel reinforcements 10 (so-called high mount backbone frames) are attached to the upper left and right corners of tunnel section 9, which protrudes into the vehicle cabin and extends in the fore-and-aft direction of the vehicle, and an upper tunnel closed cross section 11 extending in the fore-and-aft direction of the vehicle is formed between this tunnel reinforcement 10 and tunnel section 9.

[0031] As shown in Figures 3 and 4, tunnel side members 12 are attached to the lower left and right corners of the above-mentioned tunnel section 9, and a tunnel lower closed cross section 13 extending in the fore-and-aft direction of the vehicle is formed between these tunnel side members 12 and the tunnel section 9.

[0032] As shown in Figures 1 and 2, an underfloor floor frame 14 with an inverted Hat-shaped cross section is attached to both the left and right sides of the floor panel 8, and a floor frame closed cross section 14a (see Figure 3) extending in the fore-and-aft direction of the vehicle is formed between the underside of the floor panel 8 and the underfloor floor frame 14, thereby improving the vehicle body rigidity of the floor structure. The under-floor floor frame 14 described above extends in the front-rear direction of the vehicle from the front end of the floor panel 8 to a predetermined position on the floor panel 8 corresponding to the rear portion of the center pillar 6.

[0033] 1 and 2, a pair of left and right rear side frames 15 are provided that extend in the vehicle front-rear direction from the rear end of the under-floor floor frame 14 to a rear end panel (not shown). The rear side frames 15 are vehicle body strength members provided on both sides of the rear seat pan 16 and the luggage compartment floor in the vehicle width direction, and a closed cross section of the rear side frame extending in the vehicle front-rear direction is formed between the rear side frames 15 and the rear floor (rear seat pan 16, luggage compartment floor).

[0034] As shown in FIG. 1, the rear portion of the side sill 1 and the front portion of the rear side frame 15 are configured to overlap in the vehicle width direction. In this embodiment, a PHEV (plug-in hybrid electric vehicle) is exemplified as the vehicle, and the vehicle is provided with the above-mentioned tunnel section 9 in order to guide exhaust gas emitted from an engine mounted at the front of the vehicle to the rear of the vehicle.

[0035] As shown in FIG. 3, a first battery unit 21 and a second battery unit 22 are provided adjacent to the inside of the side sill 1 in the vehicle width direction, below the floor panel 8 and separated from each other in the vehicle width direction with a tunnel portion 9 between them.

[0036] Each of the above-mentioned first and second battery units 21, 22 comprises a battery 18 consisting of a plurality of battery modules 17, a battery tray 23 having a concave cross-section that covers the lower part of the battery 18, and a battery cover 24 having an inverted concave cross-section that covers the upper part of the battery 18.

[0037] That is, in each of the first and second battery units 21, 22, the battery 18 is supported by the battery tray 23, and the battery 18 is disposed in a battery storage space 25 surrounded by the battery tray 23 and the battery cover 24. Moreover, the bottom surface of the battery tray 23 in each of the battery units 21, 22 described above is formed to be approximately flat in consideration of aerodynamic performance.

[0038] As shown in Figures 1 and 2, a connector connection portion 26 is provided at the front inside of the first battery unit 21 in the vehicle width direction, and a high-voltage cable 28 is configured to connect between an inverter 27, which serves as a high-voltage device provided in front of the first battery unit 21, and the above-mentioned connector connection portion 26.

[0039] The high voltage cable 28 described above has an inverter side connector 29 and a battery side connector 30 at its front and rear ends. The inverter side connector 29 is connected to the inverter 27, and the battery side connector 30 is connected to the connector connection portion 26.

[0040] The above-mentioned inverter 27 is a power conversion device that obtains AC power from DC power of the battery 18, and this is for driving the wheels with an AC motor in order to increase the efficiency of the motor drive system.

[0041] As shown in FIG. 1, a relay unit 31 that switches an electric circuit of the vehicle is fixed to at least one of the first battery unit 21 and the second battery unit 22. In this embodiment, a plurality of relays 33, 34, 35, and 36 are attached to the back surface of a junction box 32 that is erected at the rear of the first battery unit 21 located on the left side of the vehicle, and these relays 33 to 36 constitute the relay section 31 described above.

[0042] Relay 33 is a negative side quick charging relay, relay 34 is a positive side quick charging relay, relay 35 is a negative side normal charging relay, and relay 36 is a positive side normal charging relay, but the types of relays 33 to 36 are not limited to this.

[0043] The outer sides in the vehicle width direction of first battery unit 21 and second battery unit 22, which are heavy objects, are fixed to the vehicle body by intermediate fixing member 37 and rear fixing member 38 shown in Figs. Intermediate fixing member 37 fixes the vehicle front-rear direction intermediate portion of each battery unit 21, 22 to the vehicle body, and as shown in Figs. 1 to 3, intermediate fixing member 37 has a battery side mounting portion 37a and a vehicle body side mounting portion 37b.

[0044] The battery-side mounting portion 37a of the intermediate fixing member 37 is fastened to the side surface of the battery tray 23 of each battery unit 21, 22 using fastening members 39 such as bolts (see FIGS. 1 and 2). The vehicle-body-side mounting portion 37b is fastened to the underside of the underfloor frame 14, which is the vehicle body frame, using fastening members 40 such as bolts and nuts (see FIG. 3).

[0045] The intermediate fixing member 37 is formed by an extrusion molding of aluminum or an aluminum alloy, with the battery side mounting portion 37a being formed into a solid structure and the vehicle body side mounting portion 37b being formed into a hollow structure.

[0046] In addition, since the upper surface of the hollow structure vehicle body side mounting portion 37b described above is fastened to the underfloor floor frame 14, an opening 37c for inserting the fastening member 40 is formed in the lower surface of the hollow structure vehicle body side mounting portion 37b. Furthermore, the intermediate fixing member 37 also serves as an energy absorbing member that absorbs a side collision load during a vehicle side collision.

[0047] On the other hand, the rear fixing member 38 fixes the rear of each battery unit 21, 22 in the fore-and-aft direction of the vehicle to the vehicle body, and as shown in Figures 1 and 2, the rear fixing member 38 has a battery side mounting portion 38a and a vehicle body side mounting portion 38b.

[0048] 1 and 2, the battery-side mounting portion 38a of the rear fixing member 38 is fastened to the rear side surface of the battery tray 23 of each battery unit 21, 22 using fastening members 41 such as bolts. Moreover, the vehicle-body-side mounting portion 38b is fastened to the underside of the rear side frame 15, which is the vehicle body frame, using fastening members 42 such as bolts and nuts. The insides of first battery unit 21 and second battery unit 22, which are heavy objects, in the vehicle width direction are suspended and supported by the vehicle body by suspension members 43 shown in FIG.

[0049] Figure 4 is a cross-sectional view taken along line BB in Figure 1, where line BB in Figure 1 corresponds to the front side of center pillar 6, and line CC in Figure 1 corresponds to the rear side of center pillar 6. Also, while Figure 4 only shows the structure at line BB, at line CC, as at line BB, each battery unit 21, 22 is supported by being suspended from the vehicle body by hanging members 43, and therefore the cross-sectional view taken along line CC is omitted.

[0050] As shown in FIG. 4, left and right hanging members 43, 43 that support first battery unit 21 and second battery unit 22 by suspending them from the vehicle body each have a battery side mounting portion 43a and a vehicle body side mounting portion 43b.

[0051] As shown in FIG. 4, a flange portion 23b is integrally formed with the upper end of a side wall portion 23a extending upward from the inner side in the vehicle width direction of the battery tray 23, and a flange portion 24b is also integrally formed with the lower end of a side wall portion 24a extending downward from the inner side in the vehicle width direction of the battery cover 24.

[0052] These flanges 24b, 23b are abutted in the vertical direction, and the battery side mounting portion 43a at the bottom of the hanging member 43 is overlapped on the upper portion of the flanges 24b, 23b, and the three members 43a, 24b, 23b are fastened together and fixed by using long bolts 44 and nuts 45. In other words, the three members 43a, 24b, 23b are fastened together by the bolts 44 and nuts 45.

[0053] As shown in FIG. 4, a bracket 46 is welded and fixed across the lower surface of the upper part of the tunnel portion 9 and the inner surface of the side of the tunnel portion 9, corresponding to the upper part of the battery hanging position by the hanging member 43. The vehicle body side mounting portion 43b at the top of the hanging member 43 is fastened and fixed to the mounting seat surface of the bracket 46 using fastening members such as bolts 47 and nuts 48.

[0054] As a result, the inner side of each battery unit 21, 22 in the vehicle width direction is suspended and supported by the tunnel section 9, which is a vehicle body strength member, via suspension members 43 at multiple points spaced apart in the front-rear direction middle of the vehicle.

[0055] Meanwhile, a front insulator 51, a middle insulator 52, and a rear insulator 53 are provided under the vehicle to cover an exhaust passage (not shown) formed by an exhaust pipe. Each of these insulators 51, 52, and 53 is formed separately and attached to the vehicle body so as to be continuous in the front-rear direction of the vehicle.

[0056] 1 to 4, the intermediate insulator 52 is located below the tunnel portion 9 between the first battery unit 21 and the second battery unit 22. The front insulator 51 is located further forward of the vehicle than the intermediate insulator 52. The rear insulator 53 is located further rearward of the vehicle than the intermediate insulator 52.

[0057] As shown in FIGS. 1 to 4, below the intermediate insulator 52, a connecting member 60 that connects the first battery unit 21 and the second battery unit 22 is provided. In detail, the above-mentioned connecting member 60 connects between the inner side in the vehicle width direction of the bottom wall of the battery tray 23 of the first battery unit 21 and the inner side in the vehicle width direction of the bottom wall of the battery tray 23 of the second battery unit 22 in the vehicle width direction (see FIG. 4).

[0058] As shown in Figures 1, 5 to 7, the above-mentioned connecting member 60 has a front first fixing portion 61F and a rear first fixing portion 61R that are spaced apart in the vehicle fore-and-aft direction and fixed to the bottom wall of the battery tray 23 of the first battery unit 21, and a second fixing portion 62 that is fixed to the bottom wall of the battery tray 23 of the second battery unit 22.

[0059] The above-mentioned front first fixing portion 61F and second fixing portion 62 are provided at the same position in the vehicle width direction, and the rear end of the rear first fixing portion 61R is located further rearward than the second fixing portion 62. In this embodiment, the entire rear first fixing portion 61R is located further rearward than the second fixing portion 62.

[0060] As shown in Figures 5 and 6, the front first fixing portion 61F is fixed to the bottom wall of the battery tray 23 of the first battery unit 21 by multiple bolts B1, B2 as multiple fixing members spaced apart in the fore-and-aft direction of the vehicle.

[0061] The rear first fixing portion 61R is fixed to the bottom wall of the battery tray 23 of the first battery unit 21 by a plurality of bolts B3, B4, B5 serving as a plurality of fixing members spaced apart in the vehicle front-rear direction.

[0062] As shown in Figures 5 and 6, the above-mentioned second fixing portion 62 is fixed to the bottom wall of the battery tray 23 of the second battery unit 22 by a plurality of bolts B6, B7, and B8 serving as a plurality of fixing members spaced apart in the fore-and-aft direction of the vehicle.

[0063] As shown in Figures 5 to 7, a main bead 63 is formed which protrudes downward and extends in the vehicle width direction from the front left end of the connecting member 60 where the above-mentioned front first fixing portion 61F is formed to near the front right end of the connecting member 60 where the second fixing portion 62 is formed.

[0064] 5 to 7, a sub-bead 64 is formed extending in the vehicle width direction, protruding upward from the right end of the main bead 63 in the vehicle width direction to the middle part of the main bead 63 in the vehicle width direction. The sub-bead 64 is formed along the rear edge part of the main bead 63. In each of the beads 63, 64 extending in the vehicle width direction, the main bead 63 is formed in a so-called downward convex structure, and the sub-bead 64 is formed in a so-called upward convex structure.

[0065] By providing the above-mentioned beads 63, 64, a plurality of ridgelines X1, X2, X3, X4, X5, and X6 extending parallel to the vehicle width direction are formed as shown in Fig. 8. The above-mentioned plurality of beads (main bead 63, sub-bead 64) extending in the vehicle width direction and the ridgelines X1 to X6 form a rigidity reducing portion 65 in the connecting member 60 that reduces the rigidity against loads in the vehicle front-rear direction.

[0066] As a result, the first fixing portion 61R and the second fixing portion 62 on the rear side are offset in the vehicle front-rear direction, resulting in a connecting structure in which they are separated in the diagonal front-rear direction. This diagonal connection results in a structure that is less likely to deform when subjected to input in the vehicle front-rear direction. In other words, the rigidity of the connecting member 60 in the vehicle front-rear direction can be improved.

[0067] On the other hand, the rigidity reducing portion 65 reduces the rigidity of the connecting member 60 against a load in the front-rear direction. As a result, the connecting member 60 has an element that increases rigidity and an element that decreases rigidity, and controls the resonance mode so as to maintain the opposite phase of the vibration form.

[0068] Therefore, the rigidity of the connecting member 60 in the fore-and-aft direction of the vehicle is controlled so that the first and second battery units 21, 22 are in an opposite-phase resonant mode with the same vibration level, and the left and right floor panels 8 are vibrated in opposite phases to cancel out the sounds generated within the vehicle cabin. In short, this is configured to suppress the vibration energy caused by the relay portion 31 of the battery units 21, 22 from being transmitted to the inside of the vehicle cabin without increasing the mass.

[0069] As shown in FIG. 5, the connecting member has a widthwise connecting portion 66 that connects the first battery unit 21 and the second battery unit 22 in a straight line in the vehicle width direction, and an oblique connecting portion 67 that connects the front portion of one battery unit to the rear portion of the other battery unit in a straight line in an oblique direction.

[0070] In this embodiment, the above-mentioned diagonal connector 67 diagonally connects the front part of the second battery unit 22 located on the right side in the vehicle width direction to the rear part of the first battery unit 21 located on the left side in the vehicle width direction.

[0071] 5, the widthwise connecting portion 66 includes a main bead 63 and a sub-bead 64, and connects the front first fixing portion 61F and the second fixing portion 62 in the width direction. The diagonal connecting portion 67 connects the second fixing portion 62 located on the front right side of the connecting member 60 to the rear first fixing portion 61R located on the rear left side of the connecting member 60 in the diagonal direction.

[0072] This allows the vibration energy to be transmitted most efficiently with respect to shear deformation. Furthermore, as shown in Figures 5 to 7, a first bead 71 protruding downward and extending in the fore-and-aft direction of the vehicle is provided adjacent to the vehicle widthwise inner side of each bolt B3, B4, B5 of the rear first fixing portion 61R, in which a plurality of bolts B3, B4, B5 as a plurality of fixing members are provided at a distance in the fore-and-aft direction of the vehicle.

[0073] If the above-mentioned first bead 71 were not present, stress would be concentrated on the front end fixing member (bolt B3) among the multiple fixing members (bolts B3, B4, B5); however, by having the above-mentioned first bead 71, the stress is distributed to the rear end side, thereby ensuring the strength reliability of the connecting member 60.

[0074] Here, the above-mentioned first bead 71 is formed so as to extend in the fore-and-aft direction of the vehicle in parallel with the arrangement direction of the bolts B3, B4, B5 and in correspondence with the front portion of the bolt B3 which is the forward-most of the bolts B3, B4, B5, and the rear portion of the bolt B5 which is the rearmost.

[0075] 5 to 7, a second bead 72 is provided adjacent to the inner side in the vehicle width direction of each of the bolts B6, B7, B8 of the second fixing portion 62, in which a plurality of bolts B6, B7, B8 as a plurality of fixing members are provided at a distance in the vehicle front-rear direction. In this embodiment, the second bead 72 is formed along the right side in the vehicle width direction of the main bead 63 extending in the vehicle width direction.

[0076] When the second bead 72 is not present, the rear ends of the multiple fixing members (bolts B6, B7, B8) side However, by providing the second bead 72, the stress is dispersed toward the front end side, thereby ensuring the strength reliability of the connecting member 60.

[0077] Here, the above-mentioned second bead 72 is formed so as to extend in the fore-and-aft direction of the vehicle in parallel with the arrangement direction of the bolts B6, B7, B8 and in correspondence with the front portion of the bolt B6 which is located furthest forward among the multiple bolts B6, B7, B8, and the intermediate portion between the other bolts B7, B8.

[0078] In addition, the above-mentioned reduced rigidity portion 65 is formed by a plurality of beads (main bead 63, sub-bead 64) extending in the vehicle width direction, and the ridge lines X1 to X6 of the beads 63, 64 in the vehicle width direction reduce the rigidity at a predetermined portion of the connecting member 60, thereby ensuring the deformation freedom of the connecting member 60 and configuring the reduced rigidity portion 65 with a simple structure.

[0079] As described above, the undercarriage structure of the vehicle in the above embodiment includes a side sill 1 extending in the front-rear direction of the vehicle on the outer side in the vehicle width direction, a first battery unit 21 and a second battery unit 22 provided adjacent to the inner side in the vehicle width direction of the side sill 1 and spaced apart in the vehicle width direction below the floor panel 8, a relay unit 31 fixed to at least one of the first battery unit 21 and the second battery unit 22 for switching the electric circuit of the vehicle, and a relay unit 32 for connecting the first battery unit 21 and the second battery unit 22. and a connecting member 60 for connecting the first battery unit 21 and the second battery unit 22, the connecting member 60 having a first fixing portion (see the front first fixing portion 61F and the rear first fixing portion 61R) fixed to the first battery unit 21 and spaced apart in the fore-and-aft direction of the vehicle, and a second fixing portion 62 fixed to the second battery unit 22, the rear end of the first fixing portion (see the rear end of the rear first fixing portion 61R) being located rearward of the second fixing portion 62, and the connecting member 60 having a rigidity reduction portion 65 that reduces the rigidity against fore-and-aft loads (see Figures 1 and 5).

[0080] According to this configuration, the rear end of the first fixing portion (the rear end of the rear first fixing portion 61R) and the second fixing portion 62 are offset in the vehicle front-rear direction, resulting in a connecting structure in which they are separated in the diagonal front-rear direction. This diagonal connection results in a structure that is less likely to deform when subjected to input in the vehicle front-rear direction. In other words, the rigidity of the connecting member 60 in the vehicle front-rear direction can be improved.

[0081] On the other hand, the rigidity reducing portion 65 reduces the rigidity against the load in the front-rear direction of the connecting member 60. This allows the connecting member 60 to have an element that increases the rigidity and an element that decreases the rigidity, and makes it possible to control the resonance mode so as to maintain the opposite phase of the vibration form.

[0082] Therefore, by controlling the rigidity of the connecting member 60 in the fore-and-aft direction of the vehicle so that the first and second battery units 21, 22 are in an opposite-phase resonant mode with the same vibration level, the left and right floor panels 8 are vibrated in opposite phases, thereby canceling out the noise generated inside the vehicle cabin.

[0083] In short, it is possible to suppress the vibration energy caused by the relay portion 31 of the battery units 21, 22 from being transmitted to the inside of the vehicle cabin without increasing the mass.

[0084] Here, the reason why the connecting member 60 needs elements that increase the rigidity and elements that decrease the rigidity is as follows. That is, if the rigidity of the connecting member 60 is increased to a certain extent, the phase shift of the vibration is reduced and the vibration energy is uniformed. As a result, the floor panel 8 can be vibrated in opposite phase, and the sound generated in the vehicle cabin can be canceled. On the other hand, if the rigidity of the connecting member 60 is excessively increased, the phase shift is eliminated, the first battery unit 21 and the second battery unit 22 move integrally in the same phase, and the vibration of the floor panel 8 is aggravated. For this reason, the connecting member 60 requires elements that increase rigidity and elements that decrease rigidity.

[0085] The deformation of the connecting member 60 caused by the relay unit 31 as the vibration source is shear deformation, but the direction of the shear stress acting on the connecting member 60 caused by the relay unit 31 as the vibration source is the fore-and-aft direction of the vehicle, and therefore it is controlled by the rigidity in the fore-and-aft direction of the vehicle.

[0086] In one embodiment of the present invention, the connecting member 60 has a widthwise connecting portion 66 that connects the first battery unit 21 and the second battery unit 22 in the vehicle width direction, and a diagonal connecting portion 67 that diagonally connects the front of one battery unit (in this embodiment, the second battery unit 22) to the rear of the other battery unit (in this embodiment, the first battery unit 21) (see Figures 1 and 5). According to this configuration, vibration energy can be most efficiently transmitted with respect to shear deformation.

[0087] In one embodiment of the present invention, the multiple fixing members (bolts B3, B4, B5) are spaced apart in the vehicle fore-and-aft direction and have a first bead 71 adjacent to the vehicle width inner side of the first fixing portion rear portion (rear first fixing portion 61R) (see Figure 5).

[0088] This configuration has the following advantages. In other words, if the first bead 71 were not present, stress would be concentrated on the front end fixing member (bolt B3) among the multiple fixing members (bolts B3, B4, B5); however, by having the above-mentioned first bead 71, the stress can be distributed to the rear end side, thereby ensuring the strength reliability of the connecting member 60.

[0089] In one embodiment of the present invention, the multiple fixing members (bolts B6, B7, B8) are arranged at a distance in the vehicle fore-and-aft direction and adjacent to the vehicle width inner side of the second fixing portion 62, which has a second bead 72 extending in the vehicle fore-and-aft direction (see Figures 1 and 5).

[0090] This configuration has the following advantages. In other words, if the second bead 72 does not exist, the rear ends of the multiple fixing members (bolts B6, B7, B8) side However, by providing the second bead 72, the stress can be dispersed to the front end side, and the strength reliability of the connecting member 60 can be ensured.

[0091] In one embodiment of the present invention, the reduced rigidity portion 65 is formed by a plurality of beads (main beads 63, sub-beads 64) extending in the vehicle width direction (see Figs. 5 and 8). According to this configuration, the rigidity at a specific portion of the connecting member 60 can be reduced by the ridge lines X1-X6 in the vehicle width direction of the beads 63, 64, thereby ensuring the deformation freedom of the connecting member 60. Therefore, with a simple configuration, it is possible to form a rigidity reducing portion 65 that reduces the rigidity against longitudinal loads.

[0092] In the configuration of the present invention and the above-mentioned embodiment, The first fixing portion of the present invention corresponds to the first fixing portion 61F on the front side and the first fixing portion 61R on the rear side of the embodiment. Similarly, The beads correspond to main bead 63 and sub-bead 64. The first fixing member corresponds to the bolts B3 to B5, The second fixing member corresponds to bolts B6 to B8, The present invention is not limited to the configurations of the above-mentioned embodiments, but may be practiced in many different ways.

[0093] For example, in the above embodiment, the relay unit 31 is provided at the rear of the first battery unit 21 via the junction box 32, but this relay unit 31 may be provided at least in one of the rear of the first battery unit 21, the front of the first battery unit 21, the rear of the second battery unit 22, and the front of the second battery unit 22. In the above embodiment, the relay section 31 is made up of a total of four relays 33, 34, 35, and 36, but the number and types of relays constituting the relay section 31 are not limited to the structure of the embodiment. [Industrial Applicability]

[0094] INDUSTRIAL APPLICABILITY As described above, the present invention is useful for a vehicle understructure in which a battery unit is mounted under the floor. [Explanation of symbols]

[0095] 1...Side sill 8…Floor panel 21…1st battery unit 22…Second battery unit 31…Relay section 60...Connecting member 61F, 61R…1st fixed part 62…Second fixed part 63...Main bead (bead) 64...Sub-bead (bead) 65…Reduced rigidity part 66…Width direction connection part 67...Diagonal connection 71…First bead 72…Second bead B3~B5...Bolts (first fixing member) B6~B8…Bolts (second fixing members)

Claims

1. A side sill extending in a vehicle front-rear direction on an outer side in a vehicle width direction; a first battery unit and a second battery unit provided adjacent to an inner side of the side sill in a vehicle width direction and spaced apart from each other in a vehicle width direction under a floor panel; a relay unit fixed to at least one of the first battery unit and the second battery unit, the relay unit switching an electric circuit of a vehicle; a connecting member connecting the first battery unit and the second battery unit, The connecting member is a first fixing portion fixed to the first battery unit and spaced apart from the first fixing portion in a vehicle front-rear direction; a second fixing portion fixed to the second battery unit, a rear end of the first fixing portion is located rearward of the second fixing portion, The connecting member is characterized in that it has a rigidity reducing portion that reduces the rigidity against a load in the front-rear direction. The undercarriage of the vehicle.

2. The connecting member has a width direction connecting portion that connects the first battery unit and the second battery unit in a vehicle width direction, and an oblique direction connecting portion that obliquely connects a front portion of one battery unit and a rear portion of the other battery unit. The vehicle underbody structure according to claim 1 .

3. The first fixing portion is fixed to the first battery unit by a plurality of first fixing members, The first fixing members are provided at intervals in the vehicle front-rear direction, and adjacent to the vehicle width direction inner side of the rear of the first fixing portion, the first fixing members having a first bead extending in the vehicle front-rear direction.

3. The vehicle underbody structure according to claim 1 or 2.

4. The second fixing portion is fixed to the second battery unit by a plurality of second fixing members, The second fixing members each have a second bead extending in the vehicle front-rear direction adjacent to an inner side in the vehicle width direction of the second fixing portion provided at a distance in the vehicle front-rear direction. The vehicle underbody structure according to any one of claims 1 to 3.

5. The reduced rigidity portion is formed by a plurality of beads extending in the vehicle width direction. The vehicle underbody structure according to any one of claims 1 to 4.

Images