Battery mounting structure in frame-type bicycles

Abstract

To obtain a battery loading structure in a frame vehicle that can ensure steering stability performance during traveling on a rough road and protect a battery pack in a compatible manner.SOLUTION: A battery loading structure 10 is applied in a frame vehicle 12 that includes: a vehicle body frame 20 including a pair of side rails 14 extending in a vehicle front-rear direction, a first cross member 24 connecting front portions of the side rails 14 in a vehicle width direction, and a second cross member 26 connecting rear portions of the side rails 14 in the vehicle width direction; a sub-frame 30 including a first frame 32 extending in the vehicle front-rear direction at the central part of the vehicle body frame 20 in the vehicle width direction, and a second frame 34 extending in the vehicle width direction at the central part of the first frame 32 in the vehicle front-rear direction, the sub-frame being disposed between the first cross member 24 and the second cross member 26; and a battery pack 40 supported by the sub-frame 30 from a vehicle lower side.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A vehicle body structure of an electric vehicle in which a plurality of cross members extending in the vehicle width direction are installed between a pair of left and right frames extending in the front-rear direction, and a battery pack is disposed above the plurality of cross members has been conventionally known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a frame vehicle is configured to ensure steering stability performance when traveling on rough roads by twisting the vehicle body frame that forms the vehicle body skeleton. Therefore, when such a frame vehicle is equipped with a battery pack in which a plurality of battery cells are arranged side by side in the front-rear direction and housed in a case, the plurality of battery cells may move in a wavy manner or the case may be damaged due to the twisting of the vehicle body frame. That is, there is a risk that the battery pack may be damaged.

[0005] On the other hand, in order to suppress the damage of the battery pack (protect the battery pack), if a reinforcing member or the like is provided on the vehicle body frame to improve the rigidity of the vehicle body frame, the vehicle body frame becomes difficult to twist, and thus the steering stability performance when traveling on rough roads deteriorates. Thus, in a frame vehicle, there is still room for improvement in a structure that enables both ensuring steering stability performance when traveling on rough roads and protecting the battery pack.

[0006] Therefore, the present invention aims to provide a battery mounting structure for a frame vehicle that can achieve both steering stability performance when driving on rough roads and protection of the battery pack. [Means for solving the problem]

[0007] To achieve the above objective, the battery mounting structure in a frame vehicle according to the first embodiment of the present invention comprises a vehicle body frame having a pair of left and right side rails extending in the longitudinal direction of the vehicle, a first cross member connecting the front portion of the side rails in the vehicle width direction, and a second cross member connecting the rear portion of the side rails in the vehicle width direction; a subframe provided between the first cross member and the second cross member, having a first frame extending in the longitudinal direction of the vehicle at the center of the vehicle width direction of the vehicle body frame, and a second frame extending in the vehicle width direction at the center of the first frame in the longitudinal direction of the vehicle; and a battery pack supported by the subframe from below the vehicle.

[0008] According to the first embodiment of the invention, a subframe is provided between a first cross member and a second cross member of the vehicle body frame, having a first frame extending in the vehicle's longitudinal direction from the center of the vehicle's width direction of the vehicle body frame, and a second frame extending in the vehicle's width direction from the center of the first frame in the vehicle's longitudinal direction of the vehicle body frame. The battery pack is supported by the subframe from the lower side of the vehicle.

[0009] Here, the area between the first cross member and the second cross member of the vehicle frame is an area where the amount of displacement due to twisting is extremely small. Therefore, if a subframe is provided in that area and the battery pack is supported by that subframe, the risk of damage to the battery pack is reduced even if the vehicle frame twists when the frame vehicle is driven on rough roads. In other words, according to the present invention, both ensuring steering stability and protecting the battery pack when the frame vehicle is driven on rough roads can be achieved. Note that the "center in the longitudinal direction of the vehicle" in the present invention also includes the "approximately center in the longitudinal direction of the vehicle" which is slightly offset in the longitudinal direction of the vehicle from the center in the longitudinal direction of the vehicle.

[0010] Furthermore, a battery mounting structure in a frame vehicle according to a second embodiment of the present invention is a battery mounting structure in a frame vehicle according to the first embodiment, wherein the subframe has a first connecting portion provided at the front end of the first frame and extending in the vehicle width direction, and a second connecting portion provided at the rear end of the first frame and extending in the vehicle width direction, wherein the outer end in the vehicle width direction of the first connecting portion and the outer end in the vehicle width direction of the second frame are connected to the side rail, and the outer end in the vehicle width direction of the second connecting portion is connected to the second cross member.

[0011] According to the second embodiment of the invention, the subframe has a first connecting portion provided at the front end of the first frame and extending in the vehicle width direction, and a second connecting portion provided at the rear end of the first frame and extending in the vehicle width direction. 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 are connected to the side rails, and the outer end of the second connecting portion in the vehicle width direction is connected to the second cross member. Therefore, the subframe stably supports the heavy battery pack.

[0012] Furthermore, the battery mounting structure in a frame vehicle according to a third embodiment of the present invention is the battery mounting structure in a frame vehicle according to a second embodiment, wherein the battery pack is connected to the first frame, the second frame, the inner portion in the vehicle width direction of the first connecting portion, and the inner portion in the vehicle width direction of the second connecting portion.

[0013] According to the third embodiment of the invention, the battery pack is connected to the first frame, the second frame, the inner portion in the vehicle width direction of the first connecting part, and the inner portion in the vehicle width direction of the second connecting part. Here, the connection points of the battery pack between the first frame, the second frame, the inner portion in the vehicle width direction of the first connecting part, and the inner portion in the vehicle width direction of the second connecting part are located in an area where the amount of displacement due to twisting is extremely small. Therefore, even if the vehicle frame twists, the risk of damage to the battery pack is further reduced, and the protective performance for the battery pack is improved.

[0014] Furthermore, the battery mounting structure in a frame vehicle according to the fourth embodiment of the present invention is a battery mounting structure in a frame vehicle according to any one of the first to third embodiments, wherein the subframe is provided on the upper side of the vehicle body frame.

[0015] According to the fourth embodiment of the invention, the subframe is provided on the upper side of the vehicle body frame. Therefore, the battery pack is separated from the road surface by a large distance, thereby improving the protection performance of the battery pack.

[0016] Furthermore, the battery mounting structure in a frame vehicle according to a fifth embodiment of the present invention is a battery mounting structure in a frame vehicle according to any one of the first to third embodiments, wherein the subframe is provided in the middle of the vehicle body frame in the vertical direction.

[0017] According to the fifth embodiment of the invention, the subframe is provided in the middle of the vehicle body frame in the vertical direction of the vehicle. Therefore, the passenger compartment space is increased, and the battery pack is separated from the road surface, thereby improving the protection performance of the battery pack.

[0018] Furthermore, the battery mounting structure in a frame vehicle according to the sixth embodiment of the present invention is a battery mounting structure in a frame vehicle according to any one of the first to third embodiments, wherein the subframe is provided on the lower side of the vehicle body frame.

[0019] According to the sixth embodiment of the invention, the subframe is provided on the lower side of the vehicle body frame. Therefore, the battery pack is positioned on the inner side of the vehicle body frame. This improves the mounting stability of the battery pack and enhances the protection of the battery pack in the event of a collision with the vehicle.

[0020] Furthermore, the battery mounting structure in a frame vehicle according to the seventh embodiment of the present invention is a battery mounting structure in a frame vehicle according to any one of the first to sixth embodiments, wherein the first frame has higher rigidity than the second frame.

[0021] According to the invention of the seventh aspect, the first frame is made more rigid than the second frame. Therefore, when the frame vehicle travels on a rough road or the like, even if the vehicle body frame twists, the movement of a plurality of battery cells housed side by side in the front-rear direction in the battery pack is suppressed from undulating.

[0022] Moreover, the battery mounting structure in the frame vehicle according to the eighth aspect of the present invention is the battery mounting structure in the frame vehicle according to any one of the second to sixth aspects, and the sub-frame is configured by integrally molding at least the first frame and the second frame.

[0023] According to the invention of the eighth aspect, the sub-frame is configured by integrally molding at least the first frame and the second frame. Therefore, compared with the case where the first frame and the second frame are not integrally molded, the moldability of the sub-frame is improved and the number of parts is reduced.

Effect of the Invention

[0024] As described above, according to the present invention, in a frame vehicle, it is possible to achieve both ensuring the steering stability performance during traveling on a rough road and protecting the battery pack.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic plan view showing the battery mounting structure in the frame vehicle according to the present embodiment. [Figure 2] It is a schematic side view showing the battery mounting structure in the frame vehicle according to the present embodiment. [Figure 3] It is a schematic perspective view showing the sub-frame constituting the battery mounting structure in the frame vehicle according to the present embodiment. [Figure 4] It is a schematic enlarged plan view showing the fastening points of the sub-frame constituting the battery mounting structure in the frame vehicle according to the present embodiment. [Figure 5] It is a schematic plan view showing the internal structure of the battery pack supported by the battery mounting structure in the frame vehicle according to the present embodiment. [Figure 6] This graph shows the torsional displacement of the battery pack due to the battery mounting structure in the frame vehicle according to this embodiment. [Figure 7] This is a schematic side view showing the battery mounting structure in a frame vehicle according to a first modified example of this embodiment. [Figure 8] This is a schematic side view showing a battery mounting structure in a frame vehicle according to a second modified example of this embodiment. [Modes for carrying out the invention]

[0026] The embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of explanation, in each figure, the arrow UP will indicate the upward direction of the vehicle, the arrow FR will indicate the forward direction of the vehicle, and the arrow RH will indicate the right direction of the vehicle. In the following description, unless otherwise specified, the directions of up and down, front and rear, and left and right will refer to the up and down direction of the vehicle, the front and rear direction of the vehicle, and the left and right direction of the vehicle (vehicle width direction).

[0027] As shown in Figure 1, the frame vehicle 12 equipped with the battery mounting structure 10 according to this embodiment is mainly an electric vehicle (BEV) or a fuel cell vehicle (FCEV). The frame vehicle 12 has a pair of left and right side rails 14 arranged on both sides in the vehicle width direction and extending in the front-rear direction. Each side rail 14 is formed in a closed cross-sectional shape when viewed in cross-section along the vehicle width direction. Front wheels and rear wheels (not shown) are arranged on the outer sides in the vehicle width direction at the front 14A and rear 14B sides of each side rail 14, respectively.

[0028] Furthermore, as shown in Figure 2, the front 14A and rear 14B sides of each side rail 14 are positioned above the central 14C side of each side rail 14 in a side view from the vehicle width direction, because a suspension unit (not shown) and other components are located on the lower side. In other words, the front 14A and rear 14B sides of each side rail 14 have inclined sections that slope forward and upward and backward and respectively from the central 14C side, and these inclined sections extend forward and backward, respectively.

[0029] Furthermore, a front bump relief reinforcement 16 extending approximately in the vehicle width direction is installed at the front end of each side rail 14 (see also Figure 1), and a rear bump relief reinforcement (not shown) extending approximately in the vehicle width direction is installed at the rear end of each side rail 14. Energy absorbing members such as crash boxes (not shown) may be provided between the front end of each side rail 14 and the front bump relief reinforcement 16, and between the rear end of each side rail 14 and the rear bump relief reinforcement.

[0030] As shown in Figure 1, multiple cross members extending in the vehicle width direction are installed between each side rail 14 between the front bump reinforcement 16 and the rear bump reinforcement. Specifically, cross members 22, 23, and 24 are installed on the front 14A side of each side rail 14, connecting the front 14A side, and three cross members 26, 27, and 28 are installed on the rear 14B side of each side rail 14, connecting the rear 14B side.

[0031] Each of the cross members 22, 23, 24 and each of the cross members 26, 27, 28 is formed in a closed cross-sectional shape or a roughly inverted "U" shape with the lower side open when viewed in cross-section along the front-rear direction. The ladder-shaped vehicle frame 20 is formed by each of the cross members 22, 23, 24 and each of the cross members 26, 27, 28 and each of the side rails 14.

[0032] In the following, of the cross members 22, 23, and 24 that connect the front 14A side of each side rail 14, the rearmost cross member 24 will be referred to as the "first cross member 24," and of the three cross members 26, 27, and 28 that connect the rear 14B side of each side rail 14, the foremost cross member 26 will be referred to as the "second cross member 26."

[0033] Furthermore, the first cross member 24 and the cross member 23 to its front support the motor for the front wheels (not shown) via a motor mount, and the second cross member 26 and the cross member 27 to its rear support the motor for the rear wheels (not shown) via a motor mount. In addition, a cab (body) (not shown) can be attached to each side rail 14, and multiple connection parts 18 for this purpose are provided on the outer surface of each side rail 14.

[0034] In the frame vehicle 12 having the vehicle body frame 20 described above, a battery pack 40 is mounted on the central part (between the wheelbases) in the front-rear direction of the vehicle body frame 20. Next, the battery mounting structure 10 that supports the battery pack 40 will be described in detail. Note that in Figure 2 and Figures 7 and 8 described later, the illustration of the connection parts 18 on the central part 14C and rear part 14B of the side rail 14 and the illustration of fastening means such as bolts are omitted.

[0035] As shown in Figures 1 and 2, 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. As shown in Figure 3, the subframe 30 has a first frame 32 that extends in the longitudinal direction from the center of the vehicle width direction of the vehicle body frame 20, and a second frame 34 that extends in the vehicle width direction from approximately the center of the longitudinal direction of the first frame 32.

[0036] In other words, the subframe 30 is constructed in a roughly "+" shape in plan view, consisting of a first frame 32 and a second frame 34, and the first frame 32 and the second frame 34 are integrally joined by welding or the like. Furthermore, the first frame 32 is configured to have higher rigidity than the second frame 34. Specifically, for example, the first frame 32 is formed with a thicker plate thickness than the second frame 34, or it is formed with a hat-shaped cross-section.

[0037] Furthermore, as shown in Figures 1 and 3, the subframe 30 has a first connecting portion 36 that extends substantially in the vehicle width direction and a second connecting portion 38 that extends substantially in the vehicle width direction. The first connecting portion 36 is provided by integrally joining its central part in the vehicle width direction to the front end (front side end) of the first frame 32 by welding or the like. The second connecting portion 38 is provided by integrally joining its central part in the vehicle width direction to the rear end (rear side end) of the first frame 32 by welding or the like.

[0038] Furthermore, the first connecting portion 36 is formed in a substantially curved shape that is convex towards the rear when viewed from above. More specifically, this first connecting portion 36 is formed in a shape that extends linearly for a predetermined length from the center in the vehicle width direction outward in the vehicle width direction, and extends linearly for a predetermined length from the outer end in the vehicle width direction of the linearly extended portion toward the front in the vehicle width direction.

[0039] Similarly, the second connecting portion 38 is formed in a substantially curved shape that is convex towards the front when viewed from above. More specifically, this second connecting portion 38 is formed in a shape (subtly "C" shaped when viewed from above) in which it extends linearly for a predetermined length from the center in the vehicle width direction outward in the vehicle width direction, extends linearly for a predetermined length from the outer end in the vehicle width direction of the linearly extended portion toward the rear in the vehicle width direction, and extends linearly for a predetermined length toward the rear from the outer end in the vehicle width direction of the linearly extended portion.

[0040] Furthermore, as indicated by the circles in Figures 1 and 4, the outer end of the first connecting portion 36 in the vehicle width direction is fastened (connected) from above to the upper surface of the front portion 14A of each side rail 14 and to the upper surface of the flange portion 14D that protrudes inward in the vehicle width direction from that upper surface, by fastening means such as a total of two bolts. The outer end of the second connecting portion 38 in the vehicle width direction is fastened (connected) from above to the outer end of the upper surface of the second cross member 26 in the vehicle width direction, by fastening means such as two bolts arranged in the front-rear direction.

[0041] Furthermore, the outer end of the second frame 34 in the vehicle width direction is fastened (connected) from above to the upper surface of the central portion 14C side of each side rail 14 and to the upper surface of the overhang portion 15 (see also Figure 2), which is integrally provided so as to extend outward in the vehicle width direction from the outer surface of the central portion 14C side, by fastening means such as a total of three bolts (one on the overhang portion 15 and one on each of the front and rear side rails 14). Accordingly, as shown in Figure 3, the second frame 34, the first connecting portion 36, and the second connecting portion 38 each have multiple through holes 34B, 36B, and 38B formed in them.

[0042] Here, the area between the first cross member 24 and the second cross member 26 of the vehicle frame 20 (which may include the front end of the second cross member 26) is an area where the torsion generated in the vehicle frame 20 when the frame vehicle 12 travels on rough roads is extremely small. In particular, the central part in the width direction and approximately the central part in the longitudinal direction between the first cross member 24 and the second cross member 26 are "torsional nodes" where the displacement due to torsion is 0.

[0043] In other words, the subframe 30 is located in an area of ​​the vehicle body frame 20 where the amount of displacement due to torsion is extremely small, and the first frame 32 and the second frame 34 are positioned at the "torsion nodes". In the following, the area in a roughly diamond shape in plan view (shown by dashed lines in Figure 4) connecting the longitudinal center of the vehicle width center of the first connecting section 36, the longitudinal center of the vehicle width center of the second connecting section 38, and the vehicle width outer end of the second frame 34 will be referred to as "Area E".

[0044] Within this area E, the displacement due to torsion in the vehicle frame 20 is extremely small, and this area has an even smaller displacement. The fastening means (through holes 34B), such as bolts, that fasten the outer end of the second frame 34 in the vehicle width direction to each protruding portion 15 and each side rail 14 are located on the imaginary line that defines area E (see Figure 4).

[0045] Furthermore, the reason why the second frame 34 is located approximately in the center in the longitudinal direction between the first cross member 24 and the second cross member 26 is that, depending on the shape of the vehicle body frame 20, the "torsion joint" may be slightly shifted forward or backward from the center in the longitudinal direction between the first cross member 24 and the second cross member 26, and this case is included.

[0046] The battery pack 40 is supported from below by the subframe 30 (in Figures 1 and 4, the battery pack 40 is shown by dashed lines). More specifically, the battery pack 40 is fastened (connected) to the first frame 32, the second frame 34, the inner portion in the vehicle width direction of the first connecting portion 36, and the inner portion in the vehicle width direction of the second connecting portion 38. Now, regarding the configuration of the battery pack 40, as shown in Figure 5, the battery pack 40 has a rectangular box-shaped case 42 that houses a plurality of battery cells 50 arranged in the front-rear direction.

[0047] Case 42 has a bottom wall (not shown) of a predetermined thickness, left and right side walls 44 of a predetermined thickness, a front wall 46 and a rear wall 48 of a predetermined thickness, and a top wall (not shown) of a predetermined thickness. On the bottom wall of case 42, a partition plate 52 of a predetermined thickness is erected at a predetermined height (close to the top wall), which extends in the front-rear direction at least in the center of the vehicle width direction and separates the left and right sides, and a partition plate 54 of a predetermined thickness is erected at approximately the center of the front-rear direction of the partition plate 52 and separates the front and rear sides. In other words, the left and right side walls 44, the front wall 46, the rear wall 48, and the partition plates 52 and 54 each have the rigidity to withstand fastening by fastening means such as bolts.

[0048] Therefore, as indicated by "●" in Figures 1 and 4, the first frame 32 and the partition plate 52 are fastened (connected) by multiple fastening means such as bolts (for example, four bolts spaced at predetermined intervals in the front-rear direction), and the second frame 34 and the partition plate 54 are fastened (connected) by multiple fastening means such as bolts (for example, two bolts spaced at predetermined intervals in the vehicle width direction).

[0049] More specifically, the front half of the first frame 32 in front of the second frame 34 is fastened at two points separated by a predetermined distance in the front-rear direction, and the rear half of the first frame 32 in rear of the second frame 34 is fastened at two points separated by a predetermined distance in the front-rear direction. Furthermore, the inner portion of the second frame 34 in the vehicle width direction is fastened at two points separated by a predetermined distance in the vehicle width direction.

[0050] Furthermore, the inner portion of the first connecting section 36, which is formed linearly in the vehicle width direction, and the front wall 46 are fastened (connected) by multiple fastening means such as bolts (for example, two bolts spaced at a predetermined interval in the vehicle width direction), and the inner portion of the second connecting section 38, which is formed linearly in the vehicle width direction, and the rear wall 48 are fastened (connected) by multiple fastening means such as bolts (for example, two bolts spaced at a predetermined interval in the vehicle width direction).

[0051] Furthermore, the outer end of the second frame 34 in the vehicle width direction (the portion in the vehicle width direction from the part fastened to each side rail 14) and the left and right side walls 44 are fastened (connected) by multiple fastening means such as bolts (for example, three bolts spaced at predetermined intervals in the front-rear direction). Accordingly, as shown in Figure 3, multiple through holes 32A, 34A, 36A, and 38A are formed in the first frame 32, the second frame 34, the first connecting portion 36, and the second connecting portion 38, respectively.

[0052] The operation of the battery mounting structure 10 in the frame vehicle 12 according to this embodiment, which has the configuration described above, will now be explained.

[0053] As described above, a subframe 30 is provided between the first cross member 24 and the second cross member 26 of the vehicle body frame 20. The subframe 30 has a first frame 32 extending in the longitudinal direction from the center of the vehicle width direction of the vehicle body frame 20, and a second frame 34 extending in the vehicle width direction from approximately the center of the first frame 32 in the longitudinal direction. The battery pack 40 is supported from below by the subframe 30.

[0054] Here, the area between the first cross member 24 and the second cross member 26 of the vehicle frame 20 is an area where the amount of displacement due to torsion is extremely small. Therefore, if a subframe 30 is provided in that area and the battery pack 40 is supported by the subframe 30, even if the vehicle frame 20 is trampled and twisted when the frame vehicle 12 is driving on rough roads, the twisting of the battery pack 40 is suppressed, thereby reducing the risk of damage to the battery pack 40.

[0055] Figure 6 shows a graph comparing the torsional displacement acting on the battery pack 40. Here, "torsional displacement" refers to the ratio of the vertical distance between the highest and lowest points when the front and rear ends of the case 42 rotate in opposite directions (i.e., twist) around a virtual central axis extending in the longitudinal direction at the center of the vehicle width and height of the battery pack 40, when viewed from the front or rear, with the monocoque vehicle being represented as "5". As shown in Figure 6, the torsional displacement acting on the battery pack 40 supported by the battery mounting structure 10 according to this embodiment is smaller than that of a monocoque vehicle, which is generally considered to be less prone to twisting (has smaller torsional displacement) than a frame vehicle (conventional).

[0056] Thus, the battery mounting structure 10 according to this embodiment makes it possible to ensure steering stability when the frame vehicle 12 is driving on rough roads and to protect the battery pack 40 at the same time. Moreover, since the battery mounting structure 10 according to this embodiment only requires the subframe 30 to be installed in an area (torsion joint) in the vehicle frame 20 where the amount of displacement due to torsion is extremely small, it is possible to suppress a significant increase in mass and manufacturing costs, and thus achieve weight reduction and cost reduction for the frame vehicle 12.

[0057] Furthermore, the subframe 30 has a first connecting portion 36 provided at the front end of the first frame 32 and extending in the vehicle width direction, and a second connecting portion 38 provided at the rear end of the first frame 32 and extending in the vehicle width direction. The outer end of the first connecting portion 36 in the vehicle width direction and the outer end of the second frame 34 in the vehicle width direction are fastened (connected) to the side rail 14 (including the flange portion 14D and the overhang portion 15), and the outer end of the second connecting portion 38 in the vehicle width direction is fastened (connected) to the second cross member 26. Therefore, the subframe 30 can stably support the heavy battery pack 40.

[0058] Furthermore, the battery pack 40 is fastened (connected) to the first frame 32, the second frame 34, the inner portion in the vehicle width direction of the first connecting portion 36, and the inner portion in the vehicle width direction of the second connecting portion 38 (see "●" in Figure 4). Here, the fastening (connection) points of the battery pack 40 to the first frame 32, the second frame 34, the inner portion in the vehicle width direction of the first connecting portion 36, and the inner portion in the vehicle width direction of the second connecting portion 38 are located in areas where the amount of displacement due to twisting is extremely small.

[0059] In particular, the first frame 32 and the second frame 34 are located at the "twist joint," and the fastening (jointing) portion of the battery pack 40 between the first frame 32 and the second frame 34 is located in area E, which has an even smaller displacement than the area where the displacement due to twisting is extremely small. Therefore, even if the vehicle body frame 20 twists when the frame vehicle 12 is driving on rough roads, the risk of damage to the battery pack 40 can be further reduced, and the protective performance for the battery pack 40 can be improved.

[0060] Furthermore, this subframe 30 is provided on the upper side of the vehicle body frame 20. Therefore, the battery pack 40 can be separated from the road surface by a large distance, thereby improving the protective performance of the battery pack 40. In addition, the first frame 32 has higher rigidity than the second frame 34. Therefore, even if the vehicle body frame 20 twists when the frame vehicle 12 is driving on rough roads, it is possible to suppress the multiple battery cells 50 housed in the battery pack 40 (case 42) in a wave-like motion in the front-to-back direction.

[0061] The operation of the battery mounting structure 10 according to this embodiment is as described above, but the subframe 30 may be provided in the middle of the vehicle body frame 20 in the vertical direction, as shown in the first modified example in Figure 7. Specifically, the outer end in the vehicle width direction of the first connecting portion 36 is fastened (connected) from above by fastening means such as two bolts to the flange portion 14E that protrudes inward in the vehicle width direction from the middle of the vertical direction on the inner surface of the front portion 14A of each side rail 14 that faces inward in the vehicle width direction.

[0062] Similarly, the outer end of the second connecting portion 38 in the vehicle width direction is fastened (connected) from above to the flange portion 14F that protrudes inward in the vehicle width direction from the middle of the vertical direction on the inner surface of the rear portion 14B of each side rail 14, which faces inward in the vehicle width direction, by fastening means such as two bolts. Then, the outer end of the second frame 34 in the vehicle width direction is fastened (connected) from above to the flange portion 14G that protrudes inward in the vehicle width direction from the middle of the vertical direction on the inner surface of the central portion 14C of each side rail 14, which faces inward in the vehicle width direction, by fastening means such as three bolts.

[0063] As a result, in a side view, the subframe 30 does not protrude above or below the vehicle body frame 20 (side rail 14), but is positioned on the inner side of the vehicle body frame 20. Therefore, compared to the above embodiment, the vertical space on the passenger compartment side can be made wider by the amount that the subframe 30 (battery pack 40) has moved downward. In addition, although the subframe 30 moves downward compared to the above embodiment, the battery pack 40 can be separated from the road surface, thus improving the protective performance of the battery pack 40.

[0064] Although not shown in the diagram, if the second cross member 26 is formed in a closed cross-sectional shape, the outer end of the second connecting portion 38 in the vehicle width direction may be fastened (connected) to the outer end of the lower surface of the second cross member 26 in the vehicle width direction from below using fastening means such as two bolts. In this case, if the height position of the lower surface of the second cross member 26 is not at an appropriate height position, the height of the second cross member 26 may be changed as appropriate.

[0065] Furthermore, the subframe 30 may be provided on the lower side of the vehicle body frame 20, as shown in the second modified example in Figure 8. Specifically, the lower surface of the front portion 14A of each side rail 14 and the flange portion 14H that protrudes inward from that lower surface in the vehicle width direction are fastened (connected) from below by fastening means such as a total of two bolts.

[0066] Furthermore, the outer end of the second connecting portion 38 in the vehicle width direction is fastened (connected) from below to the flange portion 14J that protrudes inward in the vehicle width direction from the lower surface of the rear portion 14B of each side rail 14 by fastening means such as a total of two bolts.The outer end of the second frame 34 in the vehicle width direction is fastened (connected) from below to the lower surface of the central portion 14C of each side rail 14 and to the lower surface of the protruding portion 17, which is formed upside down from the protruding portion 15 by fastening means such as a total of three bolts.

[0067] As a result, in a side view, the subframe 30 is positioned below the vehicle frame 20 (side rail 14), and the battery pack 40 is positioned inside the vehicle frame 20. In other words, in a side view, at least a portion of the battery pack 40 (case 42) in the height direction overlaps with the vehicle frame 20, and at least a portion of the left and right side walls 44, front wall 46, and rear wall 48 of the battery pack 40 (case 42) in the height direction is enclosed by the vehicle frame 20.

[0068] Therefore, the mounting stability of the battery pack 40 can be improved, and the protective performance of the battery pack 40 during a collision with the frame vehicle 12 can be improved. In other words, even if a collision load is applied to the frame vehicle 12 from the longitudinal direction or the width direction, the battery pack 40 can be more effectively protected from that collision load.

[0069] As with the above, although not shown in the diagram, if the second cross member 26 is formed in a closed cross-sectional shape, the outer end of the second connecting portion 38 in the vehicle width direction may be fastened (connected) to the outer end of the lower surface of the second cross member 26 in the vehicle width direction from below using fastening means such as two bolts. In this case, if the height position of the lower surface of the second cross member 26 is not at an appropriate height position, the height of the second cross member 26 may be changed as appropriate.

[0070] Furthermore, the subframe 30 is not limited to one in which the first frame 32, second frame 34, first connecting portion 36, and second connecting portion 38 are integrally joined by welding or the like. At least the first frame 32 and the second frame 34 may be integrally molded from among the first frame 32, second frame 34, first connecting portion 36, and second connecting portion 38. This improves the moldability (dimensional accuracy) of the subframe 30 and reduces the number of parts compared to the case where the first frame 32 and the second frame 34 are not integrally molded.

[0071] The battery mounting structure 10 of the frame vehicle 12 according to this embodiment has been described above based on the drawings. However, the battery mounting structure 10 of the frame vehicle 12 according to this embodiment is not limited to the illustrated structure, and can be modified as appropriate without departing from the spirit 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, bonding, etc., or the first frame 32 and the first connecting portion 36 and the second connecting portion 38 may be integrally formed by fastening, bonding, etc.

[0072] Although not shown in the diagram, the battery pack 40 may also be fastened (connected) to the subframe 30 so that it is suspended from it. In this case, the partition plates 52 and 54 should be integrally suspended from the top wall of the case 42 at a predetermined height (a height close to the bottom wall). In this case, it is preferable from the viewpoint of protecting the battery pack 40 to provide an under cover with higher strength than usual on the lower side of the battery pack 40. [Explanation of Symbols]

[0073] 10 Battery mounting structure 12 frame bike 14 Side Rails 20 Body frame 24. First Crossmember 26. Second Crossmember 30 Subframes 32. First Frame 34. Frame 2 36 1st connection part 38 2nd connection part 40 battery packs

Claims

1. A vehicle body frame having a pair of left and right side rails extending in the longitudinal direction of the vehicle, a first cross member connecting the front portion of the side rails in the vehicle width direction, and a second cross member connecting the rear portion of the side rails in the vehicle width direction. The vehicle body frame comprises a first frame extending in the vehicle longitudinal direction from the center of the vehicle width direction, and a second frame extending in the vehicle width direction from the center of the vehicle longitudinal direction from the center of the first frame, with a subframe provided between the first cross member and the second cross member. The battery pack is supported on the subframe from the lower side of the vehicle, Equipped with, The aforementioned subframe is The first frame has a first connecting portion provided at the front end of the vehicle and extending in the vehicle width direction, A battery mounting structure in a frame vehicle in which the outer end in the vehicle width direction of the first connecting portion and the outer end in the vehicle width direction of the second frame are connected to the side rail.

2. The aforementioned subframe is The first frame has a second connecting portion provided at the rear end of the vehicle and extending in the vehicle width direction, The battery mounting structure in a frame vehicle according to claim 1, wherein the outer end of the second connecting portion in the vehicle width direction is connected to the second cross member.

3. The battery mounting structure in a frame vehicle according to claim 2, wherein the battery pack is connected to the first frame, the second frame, the inner portion in the vehicle width direction of the first connecting portion, and the inner portion in the vehicle width direction of the second connecting portion.

4. The battery mounting structure in a frame vehicle according to claim 3, wherein the subframe is provided on the upper side of the vehicle body frame.

5. The battery mounting structure in a frame vehicle according to claim 3, wherein the subframe is provided in the middle of the vehicle body frame in the vertical direction of the vehicle.

6. The battery mounting structure in a frame vehicle according to claim 3, wherein the subframe is provided on the lower side of the vehicle body frame.

7. A battery mounting structure in a frame vehicle according to any one of claims 1 to 6, wherein the first frame has higher rigidity than the second frame.

8. The battery mounting structure in a frame vehicle according to any one of claims 2 to 6, wherein the subframe is formed by integrally molding at least the first frame and the second frame.

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