Vehicular body lower section structure

Abstract

To provide a vehicular body lower section structure that causes a shock absorbing function to effectively act while suppressing an increase in size and weight.SOLUTION: A vehicular body includes: a shock absorbing member 15 that absorbs a shock caused by a collision; and a battery case BC that stores therein a battery B. A projecting portion 6 that projects from the battery case BC in a vehicle-exterior direction has an uneven structure 6C in which a plurality of uneven portions where recesses recessed in a vehicle downward direction and protrusions protruding in a vehicle upward direction are continued are formed on a plate member. The shock absorbing member 15 and the battery case BC are coupled to each other in a state where the shock absorbing member 15 and the uneven structure 6C are arranged at a position overlapping with each other in a vertical direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a vehicle body lower structure.

Background Art

[0002] Patent Document 1 shows a structure in which an under cover is arranged below a floor panel of a vehicle body equipped with a motor as a driving power source, and a battery is arranged between the floor panel and the under cover.

[0003] In this Patent Document 1, rockers are provided on both the left and right sides of the floor panel, an impact absorbing member (impact absorbing material in the document) is accommodated in the internal space of the rocker, and the outer surface of the rocker in the vehicle width direction and the impact absorbing member are fastened from the outside of the rocker.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The impact absorbing member functions to absorb an impact load by plastic deformation of a plurality of small spaces in the vehicle width direction when receiving an impact load due to a collision.

[0006] However, in order for the impact absorbing member to absorb a set impact load, it is necessary to have a size and a wall thickness corresponding to the set impact load, and there is a concern that it may lead to an increase in size and weight.

[0007] For these reasons, there is a need for a vehicle body lower structure that effectively functions the impact absorbing function while suppressing an increase in size and weight.

Means for Solving the Problems

[0008] The characteristic configuration of the vehicle body lower structure according to the present invention is that the vehicle body is provided with a shock absorbing member that absorbs the impact caused by a collision and a battery case that houses a battery, and an overhanging portion that protrudes from the battery case in the vehicle exterior direction has a concavo-convex structure in which a plurality of concavo-convex portions in which a concave portion that is recessed in the vehicle downward direction and a convex portion that protrudes in the vehicle upward direction are continuous are formed on a plate material, and the shock absorbing member and the battery case are connected in a state where the shock absorbing member and the concavo-convex structure are arranged at positions that overlap vertically.

[0009] According to this configuration, the overhanging portion that protrudes from the battery case in the vehicle exterior direction has a concavo-convex structure in which a plurality of concavo-convex portions in which a concave portion that is recessed in the vehicle downward direction and a convex portion that protrudes in the vehicle upward direction are continuous, and this concavo-convex structure is connected in a positional relationship that overlaps vertically with the shock absorbing member. Therefore, at the time of a collision, the shock absorbing member and the concavo-convex structure can be plastically deformed simultaneously to absorb the impact. Since this configuration enables the plurality of concavo-convex portions formed in the overhanging portion to have a shock absorbing function, it is possible to reduce the size and thickness of the shock absorbing material. Accordingly, a vehicle body lower structure is configured that effectively functions the shock absorbing function while suppressing an increase in size and weight. In particular, in this vehicle body lower structure, since it is possible to expand the battery accommodation space of the battery case, it is also possible to increase the cruising range of the vehicle.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the underbody structure according to the present invention will be described with reference to the drawings. However, the structure for connecting the case support portion and the shock absorbing member is not limited to the following embodiment, and various modifications are possible without departing from the gist thereof.

[0012] 〔Basic Configuration〕 As shown in FIGS. 1 and 2, a vehicle body A of a vehicle capable of traveling by electric power is configured by providing a vehicle body frame F made of steel material with left and right front wheels 1 and left and right rear wheels 2, a battery B at the center of the vehicle body frame F, and a drive unit 3 for driving the rear wheels 2 at the rear of the vehicle body frame F.

[0013] The vehicle is configured as a hybrid vehicle (HEV: Hybrid Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a battery vehicle (BEV: Battery Electric Vehicle), a fuel cell vehicle (FCEV: Fuel Cell Electric Vehicle), or the like.

[0014] Although the specific structure is not shown in the drawings, the drive unit 3 includes a traveling electric motor, an inverter that controls the electric power supplied from the battery B to the electric motor, a reduction gear that transmits the driving force of the electric motor to the left and right rear wheels 2, and a housing that houses these. Note that the drive unit 3 may be arranged in the motor room so as to apply a driving force to the front wheels 1, or the drive unit 3 may be arranged in the front and rear of the vehicle so as to apply a driving force to the front wheels 1 and the rear wheels 2.

[0015] As shown in FIGS. 1 and 2, the vehicle body frame F has left and right front side members 11 arranged at left and right positions in the vehicle width direction and extending in the vehicle front-rear direction, left and right rocker frames 12, and left and right rear side members 13.

[0016] The vehicle body frame F of this embodiment creates a space between a plurality of press-worked steel plates by joining them using techniques such as spot welding, and makes the region where the space is formed function as a strength member.

[0017] The vehicle body frame F may be composed of a combination of pipe-shaped steel materials. Also, the shape of the vehicle body frame F is not limited to that shown in FIG. 1, and may have any shape or structure, such as bending the side member according to the structure of the drive system.

[0018] The battery B has a configuration in which a plurality of battery cells (not shown), which are configured as rechargeable secondary batteries, are housed in a battery case BC. The battery B is disposed below the floor AF of the vehicle body A in the middle of the left and right rocker frames 12.

[0019] As shown in FIG. 4, in this vehicle body A, an impact absorbing member 15 is provided below the left and right rocker frames 12 (the left rocker frame 12 is shown in FIG. 4) at a position overlapping the rocker frames 12. The entire impact absorbing member 15 is formed of an aluminum material and has a plurality of member spaces 15a extending in the vehicle longitudinal direction.

[0020] The impact absorbing member 15 functions to absorb an impact by plastic deformation, for example, when contacting another vehicle or a guard rail, etc., and to mitigate the impact acting on the passengers and the devices of the vehicle body A.

[0021] 〔Vehicle body lower structure〕 In the following description, as shown in FIG. 2, the direction along the front and rear of the vehicle body A may be referred to as the longitudinal direction X, the direction along the width of the vehicle body A may be referred to as the vehicle width direction Y, and the direction along the up and down of the vehicle body A may be referred to as the vertical direction Z.

[0022] As shown in FIGS. 3 to 5, the battery case BC forms a battery accommodation space BS that is open upward by a bottom wall portion 4 having a rectangular shape and a vertical wall portion 5 disposed at a position surrounding the bottom wall portion 4 by forming a steel plate. This battery case BC integrally forms an overhanging portion 6 made of a steel plate that protrudes outward in the vehicle width direction Y (laterally outward) from both end portions in the vehicle width direction Y among the upper ends of the vertical wall portion 5 of the battery case BC.

[0023] As shown in FIG. 2, in a region surrounding the upper opening of the battery case BC, case reinforcing portions 7 made of steel plates continuous with the left and right overhanging portions 6 are formed at the upper ends of the vertical wall portion 5 on the front side and the rear side. That is, the case reinforcing portions 7 are formed such that one extends forward along the front-rear direction X and the other protrudes rearward. As a result, in a plan view, the left and right overhanging portions 6 and the front and rear case reinforcing portions 7 are integrally formed with the vertical wall portion 5 so as to surround the opening of the battery case BC (the opening formed by the vertical wall portion 5).

[0024] As shown in FIGS. 2 and 4, an upper case UC is disposed below the floor AF (see FIG. 1) above the battery case BC. The upper case UC is formed in a rectangular shape in a plan view by forming a steel plate, and includes a top plate 8 having a bulging portion 8a that bulges downward so as to fit into the upper opening of the battery case BC, and a plate-shaped fixing plate 9 that protrudes outward in the vehicle width direction Y (laterally outward) along the vehicle width direction Y from the top plate 8.

[0025] Further, in a region surrounding the outer periphery of the top plate 8 of the battery case BC, a reinforcing body 9a made of a steel plate continuous with the left and right fixing plates 9 is integrally formed in front of and behind the top plate 8.

[0026] As shown in FIG. 2, a plurality of cross members 10 made of steel plates are joined to the upper surface of the top plate 8 of the upper case UC by welding or the like to reinforce the upper case UC. As shown in FIG. 5, the cross member 10 is formed by shaping a steel plate so that a trapezoid is formed by an upper wall and a pair of side walls, and is arranged with its longitudinal direction along the vehicle width direction Y of the vehicle body A. In particular, as shown in FIG. 4, the ends of the plurality of cross members 10 are arranged at positions that abut on the bulging portion 8a of the top plate 8.

[0027] As shown in FIG. 5, the overhanging portion 6 of the battery case BC is configured as an uneven structure 6C in which a protruding wall 6Ca (an example of a convex) protruding upward and a bottom wall 6Cb (an example of a concave) recessed downward are alternately continuous with respect to the plate material forming the overhanging portion 6. One protruding wall 6Ca and one adjacent bottom wall 6Cb constitute one uneven portion 6Cab, and the uneven structure 6C is formed by a plurality of uneven portions 6Cab.

[0028] In a plan view, the direction in which the protruding wall 6Ca and the bottom wall 6Cb are arranged is along the longitudinal direction X of the vehicle body A. The line at the boundary between the protruding wall 6Ca and the bottom wall 6Cb will be along the vehicle width direction Y of the vehicle body A.

[0029] As shown in FIGS. 3 and 4, the upper case UC is arranged at a position covering the open portion above the battery case BC that houses the battery B. With this arrangement, the fixing plate 9 is located above the uneven structure 6C of the overhanging portion 6. From such a positional relationship, a shock absorbing member 15 is arranged above the fixing plate 9, and these are connected by co-fastening using bolts 16 (the details of this structure will be described later).

[0030] FIG. 4 shows the shock absorbing member 15 arranged on one side in the left-right direction of the vehicle body A, but the shock absorbing members 15 are arranged on both sides of the vehicle body A at positions sandwiching the battery B in a plan view. In the vehicle body connection structure described below, the left and right shock absorbing members 15 are connected by a structure equivalent to the structure shown in the drawing.

[0031] 〔Vehicle body lower structure: Connection form〕 As shown in FIGS. 4 and 5, the underbody structure arranges the bottom surface of the fixing plate 9 in contact with the upper surface of the concavo-convex structure 6C of the protruding portion 6, and further arranges the shock absorbing member 15 in contact with the upper surface of the fixing plate 9. Bolt insertion holes penetrating in the vertical direction are formed in the protruding wall 6Ca of the concavo-convex structure 6C, the fixing plate 9, and the shock absorbing member 15.

[0032] The support plate 17 is accommodated inside the member space 15a of the shock absorbing member 15, and the nut 18 is welded and fixed at a position overlapping the hole formed in the support plate 17. In this underbody structure, the rocker frame 12 is arranged above the shock absorbing member 15.

[0033] As shown in FIG. 4, a sealing material S that deforms flexibly like resin or rubber is arranged between the outer surface of the bulging portion 8a of the top plate 8 of the upper case UC and the inner end surface in the vehicle width direction Y of the concavo-convex structure 6C. By arranging the sealing material S in this way, the intrusion of rainwater and dust into the battery case BC from the left and right sides of the vehicle body A is prevented.

[0034] Although not shown in the drawings, in the respective regions of the front end and the rear end of the battery case BC and the front end and the rear end of the upper case UC corresponding thereto, the case reinforcing portion 7 and the reinforcing body 9a are in an overlapping positional relationship. Therefore, by arranging a sealing material (not shown) between the case reinforcing portion 7 and the reinforcing body 9a, the intrusion of rainwater and dust into the battery case BC is prevented.

[0035] In the arrangement shown in FIGS. 4 and 5, the bolt 16 is inserted from the lower surface side of the concavo-convex structure 6C upward, and the female screw portion of the bolt 16 is screwed into the nut 18 inside the member space 15a of the support plate 17, and they are connected in a co-fastened state. Thereby, the concavo-convex structure 6C of the battery case BC, the fixing plate 9 of the upper case UC, and the shock absorbing member 15 are integrated respectively.

[0036] Although one bolt 16 is shown in the drawing, in this underbody structure, a plurality of bolts 16 are used for connection.

[0037] In this vehicle body lower structure, for example, it is also possible to form a female screw portion on the shock absorbing member 15 and connect the bolt 16 to be screwed into this female screw portion.

[0038] Further, in the vehicle body lower structure, the uneven structure 6C of the battery case BC, the fixing plate 9 of the upper case UC, and the shock absorbing member 15 are integrated by tightening them together with bolts 16. Due to such a structure, when an impact is applied from the outside, the shock absorbing member 15 and the uneven structure 6C of the protruding portion 6 are plastically deformed to absorb the shock.

[0039] In particular, since the direction in which the uneven portions 6Cab of the uneven structure 6C are arranged is along the longitudinal direction X of the vehicle body A, it becomes possible to withstand the force acting from the outside of the vehicle. When an impact acts on the uneven structure 6C, it receives the force while absorbing the impact and undergoes plastic deformation.

[0040] 〔Operation and Effect of Embodiment〕 In this way, by integrating the uneven structure 6C of the battery case BC, the fixing plate 9 of the upper case UC, and the shock absorbing member 15 respectively, when an impact is applied from the outside as in the case where the vehicle body A comes into contact with another vehicle or a guardrail, etc., the shock absorbing member 15 and the uneven structure 6C of the protruding portion 6 are plastically deformed to absorb the shock.

[0041] Since a plurality of protruding walls 6Ca and a bottom wall 6Cb are press-formed or the like to form the uneven structure 6C on the protruding portion 6 of the battery case BC, compared with a configuration using a special reinforcing frame or the like, the number of parts is not increased, and the shock absorbing function can be increased at low cost.

[0042] Also, in this configuration, since the uneven structure 6C of the protruding portion 6 enables absorption of the shock, it is also possible to make the shock absorbing member 15 thinner, and as a result, it is possible to reduce the weight and size of the shock absorbing member 15. Thereby, in the plan view, the arrangement space of the shock absorbing member 15 is reduced on the outer side of the battery B, and by expanding the dimension in the vehicle width direction Y of the battery accommodation space BS, the capacity of the battery cell is increased to increase the cruising range of the vehicle.

[0043] In this lower body structure, at least a part of the cross member 10 and the shock absorbing member 15 are arranged in a positional relationship where they face (overlap) each other in the vehicle width direction Y in a side view of the vehicle body A, and a fixing plate 9 that protrudes outward from the cross member 10 in the vehicle exterior direction is connected to the shock absorbing member 15. Therefore, when an impact is applied to the shock absorbing member 15 from the outside, this impact force is transmitted to the cross member 10 via the fixing plate 9, and it becomes possible to receive it with a plurality of cross members 10.

[0044] Furthermore, when the shock absorbing member 15 moves toward the center side of the vehicle body A due to an impact applied from the outside, the cross member 10 contacts the shock absorbing member 15 to receive the load acting from the shock absorbing member 15, and it becomes possible to protect the driver and passengers.

[0045] 〔Alternative Embodiment〕 The present invention may be configured as follows in addition to the above-described embodiment (components having the same functions as those in the embodiment are given the same numbers and reference signs as in the embodiment).

[0046] (a) Configure the shock absorbing member 15 to be accommodated in the internal space of the rocker frame 12 in the same manner as in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2023-117812). In the configuration of this alternative embodiment (a), the bottom surface of the shock absorbing member 15 is arranged to contact the inner surface of the bottom wall member of the rocker frame 12, the fixing plate 9 of the upper case UC is arranged on the lower surface of this bottom wall member, and the overhanging portion 6 is arranged to overlap this on the lower side, and a configuration in which these are connected by bolts 16 penetrating in the vertical direction can be considered.

[0047] Even in such a configured lower body structure, when an impact is applied from the outside, an impact force is applied to the shock absorbing member 15 via the outer wall of the rocker frame 12, and the uneven structure 6C of the fixing plate 9 connected thereto is plastically deformed to enable absorption of the impact.

[0048] (b) It is also conceivable to arrange so that a gap is formed vertically between the projecting portion 6 and the shock absorbing member 15, and connect them in a separated state by a fastening member such as a bolt 16.

[0049] Such a vehicle body lower structure will be fastened in a form in which a cylindrical member such as a collar between the shock absorbing member 15 and the projecting portion 6, or a plurality of washers are arranged and the bolt 16 is inserted through the cylindrical member and the washers. However, when an external shock is applied, the shock can be absorbed by the plastic deformation of the uneven structure 6C between the shock absorbing member 15 and the projecting portion 6.

[0050] (c) In a configuration using a bolt as the fastening member, as partially described in the embodiment, it is also possible to configure to form a female screw portion on the shock absorbing member 15 and fasten by screwing the male screw portion of the bolt into this female screw portion. Thereby, a nut becomes unnecessary and reduction of the number of parts is possible.

[0051] (d) Set the direction in which the uneven portions 6Cab of the uneven structure 6C are arranged in an oblique posture with reference to the front-rear direction X of the vehicle body A in plan view. The direction in which the uneven portions 6Cab of the uneven structure 6C are arranged does not necessarily have to be along the front-rear direction X of the vehicle body A, and it is also possible to set it in an oblique posture with reference to the direction along the front-rear direction X of the vehicle body A in plan view. Even if it is set in this way, the shock absorbing function is not impaired. That is, even if it is in a slightly oblique posture with respect to the front-rear direction X, it is sufficient that the direction in which the uneven portions 6Cab of the uneven structure 6C are arranged is along the front-rear direction X of the vehicle body A in plan view.

[0052] Further, the uneven row of the uneven structure 6C is not limited to a straight line, and for example, it may be curved, meandering, or bent in plan view.

[0053] Furthermore, the configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Also, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

[0054] In the above-described embodiment, the following configurations are recalled. (1) A vehicle body A is provided with a shock absorbing member 15 that absorbs shock due to a collision and a battery case BC that houses a battery B. An overhanging portion 6 that protrudes from the battery case BC in the vehicle exterior direction has an uneven structure 6C in which a plurality of uneven portions 6Cab in which a concave portion that depresses downward in the vehicle and a convex portion that protrudes upward in the vehicle are continuous are formed on a plate material. The shock absorbing member 15 and the battery case BC are connected in a state where the shock absorbing member 15 and the uneven structure 6C are arranged at positions overlapping vertically.

[0055] According to this, the uneven structure 6C formed in the overhanging portion 6 that protrudes from the battery case BC in the vehicle exterior direction is connected in a positional relationship overlapping vertically with the shock absorbing member 15. For this reason, at the time of a collision, it becomes possible to plastically deform the shock absorbing member 15 and the uneven structure 6C simultaneously to absorb the shock. In this configuration, since the overhanging portion 6 has a plurality of uneven structures 6C having a shock absorbing function, it is not necessary to enhance the performance of the shock absorbing function of the shock absorbing member 15, and it becomes possible to reduce the size and thickness of the shock absorbing member 15.

[0056] (2) In the vehicle body lower structure of (1), the battery case BC is disposed in the lower region of the floor AF of the vehicle body A, and a plurality of cross members 10 are disposed on the upper surface of the upper case UC of the battery case BC. It is preferable that at least a part of the cross member 10 and at least a part of the uneven structure face each other in the vehicle width direction.

[0057] According to this, when an impact is applied to the uneven structure from the outside, this impact force is directly transmitted to the cross member 10, or is transmitted to the cross member 10 via the fixing plate 9. The cross member 10 is arranged along the vehicle body width direction, and since the impact absorbing member 15 is arranged to face the cross member 10 in the vehicle outer direction, the impact can be transmitted to a plurality of cross members 10 via not only the uneven structure and the fixing plate 9 but also the impact absorbing member 15, and it is also possible to receive the impact with this cross member 10. As a result, the battery B can be reliably protected.

[0058] (3) In the vehicle body lower structure of (1) or (2), the upper case UC has a fixing plate 9 that projects in the vehicle outer direction, and the impact absorbing member 15, the fixing plate 9 arranged below the impact absorbing member 15, and the uneven structure 6C of the battery case BC having the uneven structure 6C arranged below the fixing plate 9 are connected by co-fastening, and it is preferable that a sealing material S is arranged between the fixing plate 9 and the uneven structure 6C.

[0059] According to this, the fixing plate 9 arranged below the impact absorbing member 15 and the lower uneven structure 6C are integrated by co-fastening, enabling high-strength impact absorption. Also, since the sealing material S is arranged between the fixing plate 9 and the uneven structure 6C, intrusion of water droplets and dust from the outside of the vehicle body A into the inside of the battery case BC is prevented.

[0060] (4) In any one of the vehicle body lower structures of (1) to (3), it is preferable that the arrangement direction of the plurality of uneven portions 6Cab in the uneven structure 6C is along the longitudinal direction of the vehicle body A in plan view.

[0061] According to this, since the arrangement direction of the plurality of uneven portions 6Cab in the uneven structure 6C is along the longitudinal direction of the vehicle body A in plan view, when an impact acts from the vehicle body width direction, it becomes possible to strongly receive the impact.

Industrial Applicability

[0062] The present invention can be used for a vehicle body lower structure.

Explanation of Symbols

[0063] 6: Protruding part, 6C: Concavo-convex structure, 6Cab: Concavo-convex part, 9: Fixed plate, 10: Cross member, 15: Impact absorbing member, A: Vehicle body, AF: Floor, B: Battery, BC: Battery case, S: Sealing material, UC: Upper case

Claims

1. a shock-absorbing member that absorbs shocks due to collisions; and a battery case that houses a battery, provided in a vehicle body, a projecting portion that projects outward from the battery case in the vehicle exterior direction has an uneven structure in which a plurality of uneven portions, each having a recess that is recessed downward in the vehicle lower direction and a protrusion that protrudes upward in the vehicle upper direction, are formed in a plate material, A lower body structure of the vehicle body in which the shock-absorbing member and the battery case are connected in a state where the shock-absorbing member and the uneven structure overlap vertically.

2. the battery case is disposed in a lower region of the floor of the vehicle body, a plurality of cross members are disposed on the upper surface of the upper case of the battery case, The lower body structure according to claim 1, wherein at least a part of the cross member and at least a part of the uneven structure face each other in the vehicle width direction.

3. the upper case has a fixing plate that projects outward in the vehicle exterior direction, the shock-absorbing member, the fixing plate disposed below the shock-absorbing member, and the uneven structure of the battery case having the uneven structure and disposed below the fixing plate are connected by co-fastening, The lower body structure according to claim 2, wherein a sealing material is disposed between the fixing plate and the uneven structure.

4. The lower body structure according to any one of claims 1 to 3, wherein the arrangement direction of the plurality of uneven portions in the uneven structure is along the longitudinal direction of the vehicle body in plan view.

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