Battery mounting structure in frame vehicle

Abstract

The invention relates to a battery mounting structure in a frame vehicle. A battery mounting structure in a frame vehicle includes: a vehicle body frame; the vehicle body frame includes a pair of left and right side members extending in a vehicle front-rear direction, a first cross member coupling vehicle front side portions of the side members in a vehicle width direction, and a second cross member coupling vehicle rear side portions of the side members in the vehicle width direction; a sub-frame including a first frame extending in the vehicle front-rear direction at a center portion of the vehicle body frame in the vehicle width direction, and a second frame extending in the vehicle front-rear direction at a center portion of the vehicle body frame in the vehicle width direction; a second frame extending in the vehicle width direction at a center portion of the first frame in the vehicle front-rear direction, and a sub-frame provided between the first cross member and the second cross member; and a battery pack supported on the subframe from a lower side of the vehicle.

Description

Technical Field

[0001] The present invention relates to a battery mounting structure in a frame vehicle. Background Art

[0002] A body structure of an electric vehicle is generally known, in which a plurality of cross members extending in the vehicle width direction are spanned between a pair of left and right frames extending in the front-rear direction, and a battery pack is arranged on the upper side of the plurality of cross members (for example, see Japanese Unexamined Patent Application Publication No. 2018-144700 (JP2018-144700 A)). Summary of the invention

[0003] By the way, a frame vehicle ensures steering stability while traveling on a rough road by twisting the body frame as a body skeleton. For this reason, if a battery pack containing a plurality of battery cells arranged in a front-rear direction in a housing is mounted on such a frame vehicle, the plurality of battery cells may move like waves or the housing may be damaged due to the twisting of the body frame. In other words, the battery pack may be damaged.

[0004] On the other hand, if the rigidity of the vehicle body frame is increased by providing the vehicle body frame with a reinforcing member to avoid damage to the battery pack (to protect the battery pack), the vehicle body frame is difficult to twist, with the result that the steering stability while running on rough roads is reduced. Thus, in a frame vehicle, there is still room for improvement in the structure for ensuring steering stability and protecting the battery pack while running on rough roads.

[0005] The present invention provides a battery mounting structure in a frame vehicle, which ensures steering stability while the frame vehicle travels on a rough road and also protects a battery pack.

[0006] A first aspect of the present invention provides a battery mounting structure in a frame vehicle. The battery mounting structure includes: a vehicle body frame, the vehicle body frame including a pair of left and right side beams extending in the vehicle front-rear direction, a first cross member connecting the vehicle front side portion of the side beam in the vehicle width direction, and a second cross member connecting the vehicle rear side portion of the side beam in the vehicle width direction; a sub-frame, the sub-frame including a first frame and a second frame, the first frame extending in the vehicle front-rear direction at the center of the vehicle body frame in the vehicle width direction, the second frame extending in the vehicle width direction at the center of the first frame in the vehicle front-rear direction, the sub-frame being arranged between the first cross member and the second cross member; and a battery pack, the battery pack being supported on the sub-frame from the lower side of the vehicle.

[0007] According to a first aspect, a subframe including a first frame and a second frame is provided between a first cross member and a second cross member of a vehicle body frame, the first frame extending in the vehicle front-rear direction at a center portion of the vehicle body frame in the vehicle width direction, and the second frame extending in the vehicle width direction at a center portion of the first frame in the vehicle front-rear direction. The battery pack is supported on the subframe from a lower side of the vehicle.

[0008] Here, the space between the first cross member and the second cross member of the vehicle body frame is an area where displacement due to torsion is extremely small. Therefore, when the subframe is provided in this area and the battery pack is supported by the subframe, even when, for example, the vehicle body frame is twisted while the frame vehicle is traveling on an undulating road, concerns about damage to the battery pack are reduced. In other words, according to the first aspect of the present invention, while the frame vehicle is traveling on an undulating road, steering stability is ensured and the battery pack is also protected. The "central portion in the vehicle front-rear direction" in the first aspect of the present invention also includes a "substantially central portion in the vehicle front-rear direction" slightly displaced in the vehicle front-rear direction from the central portion in the vehicle front-rear direction.

[0009] In the battery mounting structure in a frame vehicle according to the second aspect of the present invention, in addition to the battery mounting structure in the frame vehicle according to the first aspect, the sub-frame may also include a first connecting portion and a second connecting portion, the first connecting portion being arranged at the vehicle front side end of the first frame, and the first connecting portion extending in the vehicle width direction, the second connecting portion being arranged at the vehicle rear side end of the first frame, and the second connecting portion extending in the vehicle width direction, and the outer end of the first connecting portion in the vehicle width direction and the outer end of the second frame in the vehicle width direction can be respectively joined to the side beam, and the outer end of the second connecting portion in the vehicle width direction can be joined to the second cross member.

[0010] According to the second aspect, the subframe includes: a first coupling portion provided at the vehicle front side end of the first frame and extending in the vehicle width direction; and a second coupling portion provided at the vehicle rear side end of the first frame and extending in the vehicle width direction. The outer end of the first coupling portion in the vehicle width direction and the outer end of the second frame in the vehicle width direction are respectively joined to the side beam, and the outer end of the second coupling portion in the vehicle width direction is joined to the second cross member. Therefore, the battery pack as a heavy load is stably supported by the subframe.

[0011] In the battery mounting structure in the frame vehicle according to the third aspect of the present invention, in addition to the battery mounting structure in the frame vehicle according to the second aspect, the battery pack can be joined to the first frame, the second frame, the inner part of the first connecting part in the vehicle width direction and the inner part of the second connecting part in the vehicle width direction.

[0012] According to the third aspect, the battery pack is joined to the first frame, the second frame, the inner portion of the first coupling portion in the vehicle width direction, and the inner portion of the second coupling portion in the vehicle width direction. Here, the joined portion of the battery pack with the first frame, the second frame, the inner portion of the first coupling portion in the vehicle width direction, and the inner portion of the second coupling portion in the vehicle width direction is a portion in an area where displacement due to torsion is extremely small. Therefore, even when the vehicle body frame is twisted, concerns about damage to the battery pack are further reduced, and the protection performance of the battery pack is improved.

[0013] In the battery mounting structure in a frame vehicle according to a fourth aspect of the present invention, in addition to the battery mounting structure in a frame vehicle according to any one of the first to third aspects, the subframe may be provided on the vehicle upper side of the vehicle body frame.

[0014] According to the fourth aspect, the subframe is provided on the vehicle upper side of the vehicle body frame. Therefore, the battery pack is significantly spaced apart from the road surface, thereby improving the protection performance of the battery pack.

[0015] In the battery mounting structure in a frame vehicle according to the fifth aspect of the present invention, in addition to the battery mounting structure in a frame vehicle according to any one of the first to third aspects, the subframe may be provided at the middle portion of the body frame in the vehicle up-down direction.

[0016] According to the fifth aspect, the subframe is provided at the middle portion of the vehicle body frame in the vehicle up-down direction. Therefore, the vehicle compartment space is increased, and the battery pack is spaced apart from the road surface, thereby improving the protection performance of the battery pack.

[0017] In the battery mounting structure in a frame vehicle according to a sixth aspect of the present invention, in addition to the battery mounting structure in a frame vehicle according to any one of the first to third aspects, the subframe may be provided on the vehicle lower side of the vehicle body frame.

[0018] According to the sixth aspect, the subframe is disposed on the vehicle lower side of the vehicle body frame. Therefore, the battery pack is disposed on the inner side of the vehicle body frame. Therefore, the mounting stability of the battery pack is improved, and the protection performance of the battery pack in the event of a collision of the frame vehicle is improved.

[0019] In the battery mounting structure in a frame vehicle according to a seventh aspect of the present invention, in addition to the battery mounting structure in a frame vehicle according to any one of the first to sixth aspects, the first frame may be higher in rigidity than the second frame.

[0020] According to the seventh aspect, the first frame is higher in rigidity than the second frame. Therefore, even when the vehicle body frame twists while the frame vehicle is traveling on a rough road, for example, the wave-like movement of the plurality of battery cells accommodated in the battery pack so as to be arranged in the vehicle front-rear direction is reduced.

[0021] In the battery mounting structure in a frame vehicle according to the eighth aspect of the present invention, in addition to the battery mounting structure in a frame vehicle according to any one of the second to sixth aspects, at least the first frame and the second frame of the subframe may be integrally formed.

[0022] According to the eighth aspect, at least the first frame and the second frame of the sub-frame are integrally formed. Therefore, compared with a case where the first frame and the second frame are not integrally formed, the formability of the sub-frame is improved and the number of parts is reduced.

[0023] As described above, according to aspects of the present invention, it is possible to ensure the steering stability while the frame vehicle travels on a rough road and also protect the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which:

[0025] Figure 1 is a schematic plan view of a battery mounting structure in a frame vehicle according to an embodiment;

[0026] Figure 2 is a schematic side view of a battery mounting structure in a frame vehicle according to an embodiment;

[0027] Figure 3 is a schematic perspective view of a subframe as a component of a battery mounting structure in a frame vehicle according to an embodiment;

[0028] Figure 4 is a schematic enlarged plan view of a fastening point of a subframe as a component of a battery mounting structure in a frame vehicle according to an embodiment;

[0029] Figure 5 is a schematic plan view of the internal structure of a battery pack supported by a battery mounting structure in a frame vehicle according to an embodiment;

[0030] Figure 6 is a diagram showing torsional displacement of a battery pack caused by a battery mounting structure in a frame vehicle according to an embodiment;

[0031] Figure 7 is a schematic side view of a battery mounting structure in a frame vehicle according to a first modification of the embodiment; and

[0032] Figure 8 is a schematic side view of a battery mounting structure in a frame vehicle according to a second modification of the embodiment. DETAILED DESCRIPTION

[0033] An embodiment according to the present invention will be described in detail with reference to the accompanying drawings. For ease of description, arrow UP indicates the upward direction of the vehicle, arrow FR indicates the forward direction of the vehicle, and arrow RH indicates the direction of the right-hand side of the vehicle, as shown in the figure as required. In the following description, unless otherwise specified, when the up-down direction, the front-back direction, and the left-right direction are mentioned, these directions are assumed to indicate the upper side and the lower side in the up-down direction of the vehicle, the front side and the rear side in the front-back direction of the vehicle, and the left side and the right side in the left-right direction of the vehicle (vehicle width direction).

[0034] like Figure 1 As shown in the figure, the frame vehicle 12 including the battery mounting structure 10 according to the present embodiment is mainly a battery electric vehicle (BEV) or a fuel cell electric vehicle (FCEV). The frame vehicle 12 includes a pair of left and right side beams 14 arranged on both sides in the vehicle width direction and extending in the front-rear direction. Each side beam 14 is formed into a closed cross-sectional shape in a cross section taken along the vehicle width direction. In the vehicle width direction, the outer side of the front portion 14A and the outer side of the rear portion 14B of each side beam 14 are respectively provided with a front wheel (not shown) and a rear wheel (not shown).

[0035] like Figure 2 As shown in FIG. 1 , a suspension unit or the like (not shown) is provided on the lower side of the front portion 14A and the lower side of the rear portion 14B of each side member 14, and therefore, in a side view in the vehicle width direction, the front portion 14A and the rear portion 14B of each side member 14 are provided on the upper side relative to the center portion 14C of the side member 14. In other words, the front portion 14A and the rear portion 14B of each side member 14 have inclined portions inclined from the center portion 14C toward the front upper side and the rear upper side, respectively, and extend from these inclined portions toward the front side and the rear side, respectively.

[0036] A front bumper reinforcement 16 extending in the substantially vehicle width direction is provided at the front end of the side member 14 (see also Figure 1). A rear bumper reinforcement (not shown) extending in a substantially vehicle width direction is provided at the rear end of the side members 14. Energy absorbing members such as crash boxes (not shown) may be provided between the front bumper reinforcement 16 and the front end of each side member 14 and between the rear bumper reinforcement and the rear end of each side member 14, respectively.

[0037] like Figure 1 As shown in , a plurality of cross members extending in the vehicle width direction are provided between the side members 14 between the front bumper reinforcement 16 and the rear bumper reinforcement. More specifically, cross members 22, 23, 24 that couple the front portions 14A of the side members 14 to each other are provided at the front portions 14A, and three cross members 26, 27, 28 that couple the rear portions 14B of the side members 14 to each other are provided at the rear portions 14B.

[0038] The cross members 22, 23, 24 and the cross members 26, 27, 28 are each formed into a closed cross-sectional shape or a generally inverted U-shape with the lower side open in a cross section taken along the front-rear direction. The ladder-shaped vehicle body frame 20 is composed of the cross members 22, 23, 24, the cross members 26, 27, 28 and the side members 14.

[0039] In the following description, among the cross members 22, 23, 24 coupling the front portions 14A of the side beams 14 to each other, the rearmost cross member 24 is referred to as a “first cross member 24”, and among the three cross members 26, 27, 28 coupling the rear portions 14B of the side beams 14 to each other, the frontmost cross member 26 is referred to as a “second cross member 26”.

[0040] The first cross member 24 and the cross member 23 on the front side of the first cross member 24 will support the front wheel motor (not shown) via the motor mount. The second cross member 26 and the cross member 27 on the rear side of the cross member 26 will support the rear wheel motor (not shown) via the motor mount. A cab (main body) (not shown) will be attached to each side beam 14, and a plurality of connection portions 18 for the cab are provided on the outer surface of each side beam 14.

[0041] In the frame vehicle 12 including the vehicle body frame 20 as described above, the battery pack 40 is to be mounted at the center portion of the vehicle body frame 20 in the front-rear direction (between the front axle and the rear axle). Next, the battery mounting structure 10 supporting the battery pack 40 will be described in detail. Figure 2 , Figure 7 and Figure 8 In the drawings (described later), the connection portions 18 at the center portion 14C and the rear portion 14B of the side member 14 and the fasteners (eg, bolts) are not shown.

[0042] like Figure 1 and Figure 2As shown in FIG. 1 , a subframe 30 made of high-tensile steel or the like is provided on the upper side of the vehicle body frame 20 between the first cross member 24 and the second cross member 26. Figure 3 As shown in FIG. 1 , the subframe 30 includes a first frame 32 extending in the front-rear direction at a center portion of the vehicle body frame 20 in the vehicle width direction, and a second frame 34 extending in the vehicle width direction at a substantially center portion of the first frame 32 in the front-rear direction.

[0043] In other words, the first frame 32 and the second frame 34 of the sub-frame 30 are formed in a substantially cross shape in a plan view, and the first frame 32 and the second frame 34 are integrally joined to each other by welding, etc. The first frame 32 is configured to be higher in rigidity than the second frame 34. Specifically, for example, the first frame 32 is formed to be thicker in thickness than the second frame 34 and is formed in a hat shape in cross section.

[0044] like Figure 1 and Figure 3 As shown in FIG. 1 , the subframe 30 includes a first coupling portion 36 extending in a substantially vehicle width direction and a second coupling portion 38 extending in a substantially vehicle width direction. The first coupling portion 36 is arranged so that the center portion of the first coupling portion 36 in the vehicle width direction is integrally joined to the front end (front side end) of the first frame 32 by welding or the like. The second coupling portion 38 is arranged so that the center portion of the second coupling portion 38 in the vehicle width direction is integrally joined to the rear end (rear side end) of the first frame 32 by welding or the like.

[0045] The first coupling portion 36 is formed into a generally curved shape that is convex toward the rear side in a plan view. More specifically, the first coupling portion 36 is formed into a shape such that: the first coupling portion 36 linearly extends outwardly in the vehicle width direction by a predetermined length from a central portion in the vehicle width direction, and then linearly extends outwardly and forwardly in the vehicle width direction by a predetermined length from an outer end of the linearly extending portion in the vehicle width direction.

[0046] Similarly, the second coupling portion 38 is formed into a generally curved shape that is convex toward the front side in a plan view. More specifically, the second coupling portion 38 is formed into a shape (generally C-shaped in a plan view) such that: the second coupling portion 38 linearly extends outwardly in the vehicle width direction from a central portion in the vehicle width direction by a predetermined length, linearly extends outwardly and rearwardly in the vehicle width direction from outer ends of the linearly extending portion in the vehicle width direction by a predetermined length, and linearly extends rearwardly from outer ends of these linearly extending portions in the vehicle width direction by a predetermined length.

[0047] like Figure 1 and Figure 4As shown by the outline circle marks in , the outer ends of the first coupling portion 36 in the vehicle width direction are each fastened (joined) from the upper side by fasteners (e.g., two bolts in total) to the upper surface of the front portion 14A of the corresponding one side member 14 and the upper surface of the flange 14D protruding inwardly in the vehicle width direction from the upper surface. The outer ends of the second coupling portion 38 in the vehicle width direction are each fastened (joined) from the upper side by fasteners (e.g., two bolts arranged in the front-rear direction) to the outer ends in the vehicle width direction on the upper surface of the second cross member 26.

[0048] The outer ends of the second frame 34 in the vehicle width direction are fastened (joined) from the upper side by fasteners to the upper surface of the center portion 14C of the corresponding one of the side members 14 and to the protrusion 15 (see also FIG. 1 ) provided integrally so as to protrude outward in the vehicle width direction from the outer surface of the center portion 14C. Figure 2 ), these fasteners are, for example, three bolts in total (one bolt for the protrusion 15 and one bolt for each of the front and rear sides of the side beam 14). Figure 3 As shown in FIG. 1 , a plurality of through holes 34B are formed in the second frame 34 , a plurality of through holes 36B are formed in the first coupling portion 36 , and a plurality of through holes 38B are formed in the second coupling portion 38 .

[0049] Here, the area between the first cross member 24 and the second cross member 26 in the vehicle body frame 20 (which may include the front end of the second cross member 26) is an area where the torsion occurring in the vehicle body frame 20 when the frame vehicle 12 travels on a rough road is extremely small. In particular, the center portion in the vehicle width direction and the substantially center portion in the front-rear direction between the first cross member 24 and the second cross member 26 correspond to a "torsion joint" in which the displacement due to the torsion is zero.

[0050] In other words, the subframe 30 is provided in an area of ​​the vehicle body frame 20 where the displacement due to torsion is extremely small, and the first frame 32 and the second frame 34 are provided at the "torsion joint". In the following description, an area having a substantially rhombus shape in a plan view (in the center of the vehicle body frame 20) obtained by connecting the center portion in the front-rear direction at the center portion in the vehicle width direction of the first coupling portion 36, the center portion in the front-rear direction at the center portion in the vehicle width direction of the second coupling portion 38, and the outer end in the vehicle width direction of the second frame 34 is referred to as Figure 4 The region (indicated by the imaginary line) is referred to as “Region E”.

[0051] The region E is a region where the displacement due to torsion is extremely small in the vehicle body frame 20, and the displacement is further small. Fasteners such as bolts (through holes 34B) that fasten the outer ends of the second frame 34 in the vehicle width direction to the protrusion 15 and the side member 14 are located on the imaginary line defining the region E (see FIG. Figure 4 ).

[0052] The reason why the second frame 34 is placed at a substantially central portion in the front-rear direction between the first cross member 24 and the second cross member 26 is because: depending on the shape of the vehicle body frame 20, the "torsion joint" may be slightly shifted forward or backward from the central portion in the front-rear direction between the first cross member 24 and the second cross member 26, and this case is included.

[0053] The battery pack 40 is supported by the subframe 30 from the lower side (at Figure 1 and Figure 4 , the battery pack 40 is indicated by an imaginary line). More specifically, the battery pack 40 is fastened (joined) to the first frame 32, the second frame 34, the inner portion of the first coupling portion 36 in the vehicle width direction, and the inner portion of the second coupling portion 38 in the vehicle width direction. Here, the configuration of the battery pack 40 will be described. Figure 5 As shown in FIG. 1 , the battery pack 40 has a rectangular box-shaped housing 42 that accommodates a plurality of battery cells 50 arranged in the front-rear direction.

[0054] The housing 42 has: a bottom wall (not shown) having a predetermined thickness; right and left side walls 44 having a predetermined thickness; a front wall 46 and a rear wall 48 having a predetermined thickness; and a top wall (not shown) having a predetermined thickness. At least the partition plate 52 and the partition plate 54 are integrally erected on the bottom wall of the housing 42 at a predetermined height (a height close to the top wall). The partition plate 52 serves as a partition member having a predetermined thickness, and extends in the front-to-rear direction at the center portion in the vehicle width direction to separate the right and left sides from each other. The partition plate 54 serves as a partition member having a predetermined thickness, and extends in the vehicle width direction at the approximately center portion of the partition plate 52 in the front-to-rear direction. In other words, the right and left side walls 44, the front wall 46, the rear wall 48, and the partition plates 52, 54 each have a rigidity to the extent that they can withstand fastening with fasteners (e.g., bolts).

[0055] Therefore, if Figure 1 and Figure 4 As shown by the solid circle marks in , the first frame 32 and the partition plate 52 are fastened (joined) to each other by fasteners such as a plurality of (for example, four at predetermined intervals in the front-to-rear direction) bolts, and the second frame 34 and the partition plate 54 are fastened (joined) to each other by fasteners such as a plurality of (for example, two at predetermined intervals in the vehicle width direction) bolts.

[0056] More specifically, the front half of the first frame 32 on the front side relative to the second frame 34 is fastened at two positions spaced at a predetermined interval in the front-rear direction, and the rear half of the first frame 32 on the rear side relative to the second frame 34 is fastened at two positions spaced at a predetermined interval in the front-rear direction. The inner side portion of the second frame 34 in the vehicle width direction is fastened at two positions spaced at a predetermined interval in the vehicle width direction.

[0057] The inner portion of the first connecting portion 36 in the vehicle width direction (formed linearly in the vehicle width direction) and the front wall 46 are fastened (joined) to each other by a fastener such as a plurality of (for example, two at predetermined intervals in the vehicle width direction) bolts, and the inner portion of the second connecting portion 38 in the vehicle width direction (formed linearly in the vehicle width direction) and the rear wall 48 are fastened (joined) to each other by a fastener such as a plurality of (for example, two at predetermined intervals in the vehicle width direction) bolts.

[0058] The outer end of the second frame 34 in the vehicle width direction (the inner portion in the vehicle width direction relative to the portion fastened to the side member 14) and the right and left side walls 44 are fastened (joined) to each other by fasteners such as a plurality of (for example, three at predetermined intervals in the front-rear direction) bolts, respectively. Figure 3 As shown in FIG. 1 , a plurality of through holes 32A are formed in the first frame 32 , a plurality of through holes 34A are formed in the second frame 34 , a plurality of through holes 36A are formed in the first coupling portion 36 , and a plurality of through holes 38A are formed in the second coupling portion 38 .

[0059] Next, the operation of the thus constructed battery mounting structure 10 in the frame vehicle 12 according to the present embodiment will be described.

[0060] As described above, the subframe 30 is provided between the first cross member 24 and the second cross member 26 of the vehicle body frame 20, and includes: a first frame 32 extending in the front-rear direction at the center portion of the vehicle body frame 20 in the vehicle width direction; and a second frame 34 extending in the vehicle width direction at the center portion of the first frame 32 in the front-rear direction. The battery pack 40 is supported from the lower side by the subframe 30.

[0061] Here, the space between the first cross member 24 and the second cross member 26 of the vehicle body frame 20 is an area where displacement due to torsion is extremely small. Therefore, when the subframe 30 is provided in this area and the battery pack 40 is supported by the subframe 30, even if the vehicle body frame 20 is twisted by bumping while the frame vehicle 12 is traveling on a rough road, for example, the twisting of the battery pack 40 is reduced, and thus concerns about damage to the battery pack 40 can be reduced.

[0062] Figure 6 : is a diagram showing a comparison between torsional displacements applied to the battery pack 40. "Torsional displacement" shows the ratio of the distances in the up-down direction between the highest portion and the lowest portion when the front and rear ends of the housing 42 are rotated (i.e., twisted) in opposite directions to each other in a front view or a back view around an imaginary center axis extending in the front-to-back direction at the center of the battery pack 40 in the vehicle width direction and the center in the height direction (wherein a unibody vehicle is "5"). Figure 6 As shown in , the torsional displacement applied to the battery pack 40 supported by the battery mounting structure 10 according to the present embodiment is smaller than that in the case of a unibody vehicle which is generally difficult to twist (has smaller torsional displacement) than a frame vehicle (conventional frame vehicle).

[0063] In this way, with the battery mounting structure 10 according to the present embodiment, it is possible to ensure steering stability while the frame vehicle 12 is traveling on a rough road and also to protect the battery pack 40. In addition, with the battery mounting structure 10 according to the present embodiment, the subframe 30 only needs to be provided in an area (torsion joint) where the displacement due to torsion is extremely small in the vehicle body frame 20. Therefore, a huge increase in weight and an increase in manufacturing cost are also suppressed, so a reduction in weight and a reduction in cost are also achieved in the frame vehicle 12.

[0064] The subframe 30 includes: a first coupling portion 36 provided at the front end of the first frame 32 and extending in the vehicle width direction; and a second coupling portion 38 provided at the rear end of the first frame 32 and extending in the vehicle width direction. The outer ends of the first coupling portion 36 in the vehicle width direction and the outer ends of the second frame 34 in the vehicle width direction are fastened (joined) to the side beam 14 (including the flange 14D and the protrusion 15), respectively, and the outer ends of the second coupling portion 38 in the vehicle width direction are fastened (joined) to the second cross member 26. Therefore, with the subframe 30, the battery pack 40 as a heavy load can be stably supported.

[0065] The battery pack 40 is fastened (joined) to the first frame 32, the second frame 34, the inner portion of the first coupling portion 36 in the vehicle width direction, and the inner portion of the second coupling portion 38 in the vehicle width direction (see Figure 4 Here, the fastening portions (engaging portions) of the battery pack 40 with the first frame 32, the second frame 34, the inner portion of the first coupling portion 36 in the vehicle width direction, and the inner portion of the second coupling portion 38 in the vehicle width direction are portions in an area where displacement due to torsion is extremely small.

[0066] In particular, the first frame 32 and the second frame 34 are located at the "torsion joint", and the fastening portion (joint portion) of the battery pack 40 and the first frame 32 and the second frame 34 is located in the region E where the displacement due to torsion is further reduced in the region where the displacement due to torsion is extremely small. Therefore, even when the vehicle body frame 20 is twisted while, for example, the frame vehicle 12 is running on a rough road, the concern about the breakage of the battery pack 40 can be further reduced, thereby improving the protection performance of the battery pack 40.

[0067] The subframe 30 is provided on the upper side of the vehicle body frame 20. Therefore, the battery pack 40 can be significantly spaced apart from the road surface, thereby improving the protection performance of the battery pack 40. The first frame 32 is higher in rigidity than the second frame 34. Therefore, even when the vehicle body frame 20 is twisted while, for example, the frame vehicle 12 is running on a rough road, the wave-like movement of the battery cells 50 accommodated in the battery pack 40 (housing 42) so as to be arranged in the front-rear direction is reduced.

[0068] The operation of the battery mounting structure 10 according to the present embodiment is described above. Figure 7 As in the case of the first modification shown in , the subframe 30 may be provided at the middle portion in the up-down direction of the vehicle body frame 20. More specifically, each outer end of the first coupling portion 36 in the vehicle width direction is fastened (joined) from the upper side by a fastener (e.g., two bolts) to a flange 14E that projects inwardly in the vehicle width direction from the middle portion in the up-down direction of the inner surface of the front portion 14A of the corresponding one of the side members 14 that faces the inner side in the vehicle width direction.

[0069] Similarly, each outer end of the second coupling portion 38 in the vehicle width direction is fastened (joined) from the upper side by fasteners (e.g., two bolts) to a flange 14F that projects inwardly in the vehicle width direction from a middle portion in the up-down direction of an inner surface of a rear portion 14B of a corresponding one of the side members 14 that faces inwardly in the vehicle width direction. Each outer end of the second frame 34 in the vehicle width direction is fastened (joined) from the upper side by fasteners (e.g., three bolts) to a flange 14G that projects inwardly in the vehicle width direction from a middle portion in the up-down direction of an inner surface of a central portion 14C of a corresponding one of the side members 14 that faces inwardly in the vehicle width direction.

[0070] Therefore, in a side view, the subframe 30 does not protrude beyond the vehicle body frame 20 (side member 14) toward the upper side or the lower side, and the subframe 30 is provided on the inner side of the vehicle body frame 20. Therefore, compared with the case of the above-described embodiment, a larger space can be occupied on the vehicle compartment side in the up-down direction by the amount by which the subframe 30 (battery pack 40) is moved to the lower side. Although the subframe 30 is moved to the lower side compared with the case of the above-described embodiment, the battery pack 40 can be spaced apart from the road surface, thereby improving the protection performance of the battery pack 40.

[0071] Although not shown in the drawings, when the second cross member 26 is formed into a closed cross-sectional shape, each outer end of the second coupling portion 38 in the vehicle width direction may be fastened (joined) from the lower side by a fastener such as two bolts to a corresponding one of the outer ends in the vehicle width direction of the lower surface of the second cross member 26. At this time, when the level of the lower surface of the second cross member 26 is not an appropriate level, the level of the second cross member 26 may be changed as needed.

[0072] The subframe 30 may be Figure 8 . More specifically, each outer end of the first coupling portion 36 in the vehicle width direction is fastened (joined) from the lower side to the lower surface of the front portion 14A of the corresponding one of the side members 14 and the flange 14H protruding inwardly in the vehicle width direction from the lower surface by a fastener (e.g., two bolts in total).

[0073] Each outer end of the second coupling portion 38 in the vehicle width direction is fastened (joined) from the lower side by a fastener (e.g., two bolts in total) to a flange 14J that protrudes inward in the vehicle width direction from the lower surface of the rear portion 14B of the corresponding one side member 14. Each outer end of the second frame 34 in the vehicle width direction is fastened (joined) from the lower side by a fastener (e.g., three bolts in total) to the lower surface of the central portion 14C of the corresponding one side member 14 and the lower surface of the protruding portion 17 formed inverted from the protruding portion 15.

[0074] Therefore, in a side view, the subframe 30 is disposed on the lower side of the vehicle body frame 20 (side member 14), and thus the battery pack 40 is disposed on the inner side of the vehicle body frame 20. In other words, in a side view, the battery pack 40 (housing 42) at least partially overlaps the vehicle body frame 20 in the height direction, and the right and left side walls 44, 45, the front wall 46, and the rear wall 48 of the battery pack 40 (housing 42) are at least partially surrounded by the vehicle body frame 20 in the height direction.

[0075] Therefore, the mounting stability of the battery pack 40 can be improved, and the protection performance of the battery pack 40 can also be improved in the event of a collision of the frame vehicle 12. In other words, even when a collision load is input to the frame vehicle 12 in the front-rear direction or in the vehicle width direction, the battery pack 40 can be further effectively protected from the impact of the collision load.

[0076] Although not shown in the figure as in the above case, when the second cross member 26 is formed in a closed cross-sectional shape, each outer end of the second coupling portion 38 in the vehicle width direction may be fastened (joined) from the lower side by a fastener (e.g., two bolts) to a corresponding one of the outer ends in the vehicle width direction of the lower surface of the second cross member 26. At this time, when the level of the lower surface of the second cross member 26 is not an appropriate level, the level of the second cross member 26 may be changed as needed.

[0077] The subframe 30 is not limited to the subframe 30 formed so that the first frame 32, the second frame 34, the first coupling portion 36, and the second coupling portion 38 are integrally joined to each other by welding or the like. Among the first frame 32, the second frame 34, the first coupling portion 36, and the second coupling portion 38, at least the first frame 32 and the second frame 34 may be integrally formed. With this configuration, the formability (dimensional accuracy) of the subframe 30 is improved, and the number of components can be reduced, compared with a case where the first frame 32 and the second frame 34 are not integrally formed.

[0078] The battery mounting structure 10 of the frame vehicle 12 according to the present embodiment has been described with reference to the drawings; however, the battery mounting structure 10 of the frame vehicle 12 according to the present embodiment is not limited to those shown in the drawings. The battery mounting structure 10 of the frame vehicle 12 according to the present embodiment may be changed in design without departing from the scope of the present invention. For example, in the subframe 30, the first frame 32 and the second frame 34 may be integrally formed by fastening, combining, etc., or both the first frame 32 and the first coupling portion 36 and the second coupling portion 38 may be integrally formed by fastening, combining, etc.

[0079] Although not shown in the drawings, the battery pack 40 may be fastened (engaged) to be suspended from the subframe 30. In this case, the partition plates 52, 54 may be integrally suspended at a predetermined horizontal plane (a horizontal plane close to the bottom wall) from the top wall of the housing 42. In this case, from the viewpoint of protecting the battery pack 40, it is preferable to provide a lower cover having a higher strength than usual on the lower side of the battery pack 40.

Claims

1. A battery mounting structure in a frame vehicle, the battery mounting structure comprising: a vehicle body frame including a pair of left and right side members extending in a vehicle front-rear direction, a first cross member coupling vehicle front side portions of the side members to each other in a vehicle width direction, and a second cross member coupling vehicle rear side portions of the side members to each other in the vehicle width direction; a subframe including a first frame and a second frame, the first frame extending in the vehicle front-rear direction at a center portion of the vehicle body frame in the vehicle width direction, the second frame extending in the vehicle width direction at a center portion of the first frame in the vehicle front-rear direction, the subframe being provided between the first cross member and the second cross member; as well as A battery pack is supported on the subframe from a lower side of the vehicle.

2. The battery installation structure according to claim 1, characterized in that: The sub-frame includes: a first link portion provided at a vehicle front side end of the first frame and extending in the vehicle width direction; and a second link portion provided at a vehicle rear side end of the first frame and extending in the vehicle width direction; and The outer ends of the first link portion in the vehicle width direction and the second frame in the vehicle width direction are respectively joined to the side members, and the outer ends of the second link portion in the vehicle width direction are joined to the second cross member.

3. The battery installation structure according to claim 2, characterized in that: The battery pack is joined to the first frame, the second frame, an inner portion of the first coupling portion in the vehicle width direction, and an inner portion of the second coupling portion in the vehicle width direction.

4. The battery installation structure according to claim 3, characterized in that: The subframe is provided on the vehicle upper side of the vehicle body frame.

5. The battery installation structure according to claim 3, characterized in that: The subframe is provided at an intermediate portion of the vehicle body frame in a vehicle up-down direction.

6. The battery installation structure according to claim 3, characterized in that: The subframe is provided on the vehicle lower side of the vehicle body frame.

7. The battery mounting structure according to any one of claims 1 to 6, characterized in that: The first frame is higher in rigidity than the second frame.

8. The battery mounting structure according to any one of claims 2 to 6, characterized in that: At least the first frame and the second frame of the sub-frame are integrally formed.

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