Vehicle underbody structure

Abstract

To secure a collision stroke in a vehicle side collision.SOLUTION: A vehicle lower section structure 100 includes: a pair of rockers 10 extending in a vehicle back-and-forth direction at both side parts of a vehicle 60; and a battery pack 30 arranged between the pair of rockers 10. Each rocker 10 includes a collision absorbing part 20 that absorbs collision energy in a vehicle widthwise direction by being collapsed in the vehicle widthwise direction in a side collision of the vehicle 60. The battery pack 30 and each rocker 10 are connected to each other at a lower side than a bottom surface 32a of the battery pack 30 and at a lower side than each lower end surface 14a of each rocker 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle underbody structure including rockers arranged on both sides of a vehicle and a battery pack arranged between the rockers. [Background technology]

[0002] In recent years, electric vehicles equipped with a battery pack mounted on the underside of a floor panel have been used. The battery pack mounted on such electric vehicles is mounted on the vehicle by fastening a flange or bracket that protrudes outward in the vehicle width direction from the bottom plate of the casing to the underside of rockers arranged on both sides of the vehicle with bolts (for example, see Patent Documents 1 and 2).

[0003] Furthermore, Patent Documents 1 and 2 disclose providing an impact absorbing portion inside the rocker that absorbs impact energy during a side collision of the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-25935 A [Patent Document 2] JP 2019-137354 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the structures described in Patent Documents 1 and 2, the bolts for attaching the battery pack protrude from the bottom surface of the rocker into the inside of the rocker. The bolts have high rigidity and will not be crushed even if the vehicle crashes sideways and the impact absorbing section is crushed in the vehicle width direction. For this reason, there is a problem that the bolts are pinched between the side impact pole and the battery pack during a side impact, and the impact absorbing section inside the rocker is not crushed by the length of the bolt in the vehicle width direction, resulting in a correspondingly shorter collision stroke.

[0006] Therefore, an object of the present invention is to ensure a collision stroke during a vehicle side collision. [Means for solving the problem]

[0007] The vehicle underbody structure of the present invention includes a pair of rockers extending in a vehicle front-rear direction on both sides of the vehicle, and a battery pack disposed between the pair of rockers, wherein each rocker is: The vehicle has a closed rectangular cross-sectional shape surrounded by an outer vertical plate on the outside in the vehicle width direction, an inner vertical plate on the inside in the vehicle width direction, a lower plate, and an upper plate. A shock absorbing portion that is crushed in a vehicle width direction when the vehicle is hit in a side collision and absorbs impact energy in the vehicle width direction. the battery pack includes a lower portion including a lower end portion, an upper portion disposed above the lower portion, and a flange disposed to overlap the inner vertical plate in a top view of the vehicle and protruding downward from a lower end surface so that an inner surface in the vehicle width direction is flush with an inner surface in the vehicle width direction of the inner vertical plate; the battery pack includes a peripheral wall surrounding the periphery, and a pair of mounting flanges disposed to overlap an outer vertical wall in the vehicle width direction of the peripheral wall in a top view of the vehicle and protruding downward from a bottom surface; and the battery pack is attached to each of the rockers with at least one bolt fastening each of the mounting flanges to each of the flanges. It is characterized by the fact that

[0008] Since the battery pack and the locker are connected below the bottom surface of the battery pack and below the lower end surfaces of the locker, the bolt will not be caught between the side impact pole and the battery pack in the event of a side impact, and the shock absorbing portion of the locker will be sufficiently crushed to ensure a collision stroke in the event of a vehicle side impact. In addition, by locating the flange on the inside of the rocker in the vehicle width direction, the position of the flange does not overlap with the impact absorbing part of the rocker when viewed from above the vehicle. Therefore, in the event of a side collision, the side impact pole can advance to the inside of the rocker in the vehicle width direction while crushing the impact absorbing part without interfering with the flange and the mounting flange. This ensures a larger collision stroke.

[0015] In the vehicle underbody structure of the present invention, the bolts may fasten the mounting flanges to each other in a direction along a lower end surface of the rocker and the bottom surface of the battery pack.

[0016] This prevents a portion of the bolt from protruding into the rocker during a side collision and becoming caught between the side collision pole and the battery pack, thereby ensuring a collision stroke during a vehicle side collision. Effect of the Invention

[0017] The present invention can ensure a collision stroke during a vehicle side collision. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a configuration of a vehicle equipped with a vehicle undercarriage structure of a reference example. [Diagram 2] 2 is a cross-sectional view showing a vehicle underbody structure of a reference example, taken along line AA in FIG. 1. [Diagram 3] 3 is a diagram showing the crushing deformation of a rocker when a vehicle equipped with the vehicle undercarriage structure shown in FIG. 2 is subjected to a side collision. [Figure 4] 1 is a cross-sectional view showing a vehicle underbody structure according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] With reference to the drawings, Reference example The vehicle underbody structure 100 will be described. First, referring to FIG. Reference example A vehicle 60 equipped with the vehicle undercarriage structure 100 will be described. The arrows FR, UP, and LH shown in each drawing indicate the forward direction (traveling direction), upward direction, and leftward direction of the vehicle 60, respectively. The opposite directions of the arrows FR, UP, and LH indicate the rearward direction, downward direction, and rightward direction of the vehicle. Hereinafter, when the directions of front-rear, left-right, and up-down are simply used for the description, they refer to front-rear in the front-rear direction of the vehicle, left-right in the left-right direction of the vehicle (vehicle width direction), and up-down in the up-down direction of the vehicle, unless otherwise specified.

[0020] As shown in FIG. 1, a vehicle 60 includes a locker 10, floor cross members 26, 27, and 28, a floor panel 25, and a battery pack 30.

[0021] The rockers 10 are disposed on both the left and right sides of the vehicle 60, and are structural members with a closed cross section extending in the front-rear direction of the vehicle. The floor panel 25 is a plate member that is placed between the left and right rockers 10, and constitutes the floor of the vehicle 60. The floor cross members 26, 27, 28 are structural members with a hat-shaped cross section that are placed between the pair of left and right rockers 10, and their lower flanges are connected to the upper surface of the floor panel 25 by spot welding. A battery pack 30 is mounted on the underside of the floor panel 25.

[0022] The battery pack 30 is composed of a plurality of battery modules 36 and a casing 31 that houses the plurality of battery modules 36. The casing 31 is composed of a peripheral wall 33 that surrounds the periphery, a bottom plate 32, a lid 34, and a cross member 35 that connects the left and right peripheral walls 33. Note that FIG. 1 illustrates a state in which the lid 34 is removed. The lid 34 is shown in FIG. 2. Furthermore, lateral flanges 41 that extend toward the outside in the vehicle width direction are provided on both side ends of the bottom plate 32 of the casing 31 in the vehicle width direction, and mounting flanges 42 that extend downward are provided on the outer ends of the lateral flanges 41 in the vehicle width direction. The mounting flanges 42 are provided with a plurality of bolt holes 43 through which bolts 50 pass.

[0023] Next, the detailed structure of the locker 10 and the mounting structure of the battery pack 30 to the locker 10 will be described with reference to Fig. 2. In the following explanation, the structure of the left side locker 10 and the mounting structure between the left end of the battery pack 30 and the left side locker 10 will be described. The structure of the right side locker 10 and the mounting structure between the right end of the battery pack 30 and the right side locker 10 are the left-right inverted structure, so the explanation will be omitted.

[0024] 2, the rocker 10 is composed of an outer vertical plate 11, an inner vertical plate 12, a lower plate 14, a lower portion 10B having a rectangular closed cross-sectional shape surrounded by an upper plate 16, an upper vertical plate 13 erected on the upper plate 16, an upper portion of the outer vertical plate 11, and an upper portion 10U composed of a ceiling plate 17. An upper flange 15 that protrudes toward the inside in the vehicle width direction is provided on the inside of the upper plate 16 of the lower portion 10B in the vehicle width direction.

[0025] A horizontal plate 21 that connects the outer vertical plate 11 and the inner vertical plate 12 is provided at a position about 1 / 3 from the bottom of the lower portion 10B. In addition, a plurality of vertical rib plates 22 that connect the horizontal plate 21 and the lower plate 14 in the up-down direction are provided between the outer vertical plate 11 and the inner vertical plate 12. The horizontal plate 21, the lower plate 14, and the plurality of vertical rib plates 22 constitute an impact absorbing portion 20 of the rocker 10 that absorbs impact energy in the event of a side collision.

[0026] A flange 18 that protrudes downward from the lower end surface 14a of the lower plate 14 is provided on the lower end surface 14a of the rocker 10. The flange 18 is a plate member that is provided on the lower end surface 14a of the rocker 10 and extends in the front-rear direction of the vehicle, and is provided with a plurality of bolt holes 19 through which bolts 50 pass.

[0027] The rocker 10 may be made, for example, of an extruded aluminum alloy.

[0028] The peripheral wall 33 of the battery pack 30 is formed by bending a long extrusion molded product formed by extrusion molding of an aluminum alloy or the like into a rectangular frame shape and joining the longitudinal ends to each other, and has a rectangular frame shape in a plan view as shown in Fig. 1. As shown in Fig. 2, the peripheral wall 33 has a rectangular closed cross-sectional shape and is provided therein with a horizontal rib 33a that divides the internal space into upper and lower parts.

[0029] A bottom plate 32 constituting the lower end of the battery pack 30 is attached to the lower surfaces of each of the four sides of the rectangular frame-shaped peripheral wall 33. A lateral flange 41 extending outward in the vehicle width direction is provided at the left end of the bottom plate 32 in the vehicle width direction, and a mounting flange 42 extending downward is provided at the left end of the lateral flange 41. The mounting flange 42 is provided with a plurality of bolt holes 43 through which bolts 50 pass.

[0030] As shown in FIG. 2, the battery pack 30 is attached to the rocker 10 by inserting a bolt 50 through a bolt hole 19 in a flange 18 provided on the lower end surface 14a of the rocker 10 and a bolt hole 43 provided in a mounting flange 42 of the battery pack 30 and tightening a nut 51.

[0031] The flange 18 protrudes downward from the lower end surface 14a of the lower plate 14 of the rocker 10, and the mounting flange 42 protrudes downward from the bottom surface 32a of the bottom plate 32 of the battery pack 30. Furthermore, each bolt hole 19, 43 is located below the bottom end surface 14a and the bottom surface 32a, respectively. Therefore, the battery pack 30 and the rocker 10 are connected below the bottom surface 32a of the battery pack 30 and below the lower end surface 14a of the rocker 10. Furthermore, the bolt 50 and the nut 51 fasten the mounting flange 42 and the flange 18 in the vehicle width direction, which is the direction along the lower end surface 14a of the rocker 10 and the bottom surface 32a of the battery pack 30.

[0032] Next, referring to Figure 3, Reference example The deformation of the rocker 10 when a vehicle 60 equipped with the vehicle underbody structure 100 crashes into a side will be described below. In Fig. 3, the dashed line indicates the state before deformation, and the solid line indicates the state after deformation.

[0033] As shown in Fig. 3, when the side impact pole 90 enters from the left side of the rocker 10 as indicated by the arrow 91 in Fig. 3, the left side portion of the impact absorbing section 20, which is composed of the left side portion of the lower plate 14 of the rocker 10 and the left side portion of the horizontal plate 21, is crushed in the vehicle width direction as indicated by the solid line in Fig. 3, and is integrated with the outer vertical plate 11 to form a crushed section 70. The upper portion 10U of the rocker 10 is also crushed in the vehicle width direction in the same manner.

[0034] Since the bolt 50 is disposed below the bottom surface 32a of the battery pack 30 and below the lower end surface 14a of the rocker 10, as shown in Fig. 3, even during a side collision the bolt 50 is located below the bottom surface 32a of the battery pack 30 and below the lower end surface 14a of the rocker 10. Therefore, during a side collision the bolt 50 will not be caught between the side collision pole 90 and the battery pack 30. Therefore, the shock absorbing section 20 disposed on the rocker 10 is sufficiently crushed, and the collision stroke L during a vehicle side collision can be secured.

[0035] Furthermore, since the bolt 50 and the nut 51 fasten the mounting flange 42 and the flange 18 in the vehicle width direction, a part of the bolt 50 does not protrude into the inside of the rocker 10 during a side collision, and the bolt 50 does not become caught between the side collision pole 90 and the battery pack 30, and the collision stroke L during a vehicle side collision can be secured.

[0036] still, Reference example In the vehicle underbody structure 100, the lateral flanges 41 of the battery pack 30 protrude outward in the vehicle width direction so as to overlap the lower end surface 14a of the lower plate 14 of the rocker 10, so that the bolts 50 and nuts 51 can be attached with the lateral flanges 41 of the battery pack 30 aligned with the lower end surface 14a of the rocker 10. This makes it easy to assemble the battery pack 30.

[0037] Next, referring to Figure 4, Rami The following describes a vehicle underbody structure 200 according to the embodiment. The same components as those in the vehicle underbody structure 100 previously described with reference to Figures 1 to 3 are designated by the same reference numerals, and descriptions thereof will be omitted.

[0038] In the vehicle underbody structure 200 shown in FIG. 4, the flange 18a of the rocker 10 is disposed at the inner end of the rocker 10 in the vehicle width direction, and the mounting flange 42a of the battery pack 30 is disposed at the side end of the bottom plate 32.

[0039] 4, the flange 18a of the rocker 10 is disposed so as to overlap with the inner vertical plate 12 of the rocker 10 in a top view of the vehicle, and is disposed so that the inner surface of the flange 18a in the vehicle width direction is flush with the inner surface of the inner vertical plate 12 of the rocker 10 in the vehicle width direction. Therefore, the flange 18a protrudes downward from the lower end surface 14a at the inner end of the rocker 10 in the vehicle width direction.

[0040] The mounting flanges 42a are disposed on the side ends of the bottom plate 32 so as to overlap with the outer vertical walls 33b of the peripheral wall 33 in the vehicle width direction when viewed from above the vehicle. Therefore, the mounting flanges 42a protrude downward from the bottom surface 32a of the bottom plate 32 at both side ends of the battery pack 30 in the vehicle width direction.

[0041] In this way, by positioning the flange 18a of the rocker 10 and the mounting flange 42a of the battery pack 30 at the inner end of the rocker 10 in the vehicle width direction, the positions of the flange 18a and the mounting flange 42a do not overlap with the impact absorbing portion 20 of the rocker 10 when viewed from above the vehicle. Therefore, in the event of a side collision, the side collision pole 90 does not interfere with the flange 18a and the mounting flange 42a, and can advance to the inner vertical plate 12 of the rocker 10 while crushing the impact absorbing portion 20. This ensures a larger collision stroke. [Explanation of symbols]

[0042] 10 rocker, 10B lower part, 10U upper part, 11 outer vertical plate, 12 inner vertical plate, 13 upper vertical plate, 14 lower plate, 14a lower end surface, 15 upper flange, 16 upper plate, 17 ceiling plate, 18, 18a flange, 19, 43 bolt hole, 20 impact absorbing part, 21 horizontal plate, 22 vertical rib plate, 25 floor panel, 26, 27, 28 floor cross member, 30 battery pack, 31 casing, 32 bottom plate, 32a bottom surface, 33 peripheral wall, 33a horizontal rib, 33b vertical wall, 34 lid, 35 cross member, 36 battery module, 41 horizontal flange, 42, 42a mounting flange, 50 bolt, 51 nut, 60 vehicle, 70 crushed part, 90 side impact pole, 100, 200 Vehicle undercarriage.

Claims

1. A pair of rockers extending in a front-rear direction of the vehicle on both sides of the vehicle; A vehicle underbody structure including: Each rocker has a rectangular closed cross-sectional shape surrounded by an outer vertical plate on the outside in the vehicle width direction, an inner vertical plate on the inside in the vehicle width direction, a lower plate, and an upper plate, and includes a lower part including an impact absorbing part that is crushed in the vehicle width direction in the event of a side collision of the vehicle to absorb impact energy in the vehicle width direction, an upper part arranged above the lower part, and a flange that is arranged to overlap the inner vertical plate in a top view of the vehicle and protrudes downward from a lower end surface so that a surface on the inside in the vehicle width direction is flush with a surface on the inside in the vehicle width direction of the inner vertical plate, The battery pack includes a peripheral wall surrounding the periphery and a pair of mounting flanges arranged to overlap with a vertical wall on an outer side of the peripheral wall in the vehicle width direction in a top view of the vehicle and protruding downward from a bottom surface of the battery pack; the battery pack is attached to each of the rockers by at least one bolt fastening each of the mounting flanges to each of the flanges; A vehicle undercarriage characterized by:

2. 2. The vehicle underbody structure according to claim 1, the bolts fasten the mounting flanges to the flanges in a direction along a lower end surface of the locker and the bottom surface of the battery pack; A vehicle undercarriage characterized by:

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