Vehicle undercarriage

Abstract

To provide a vehicle underbody structure capable of reducing the possibility of a collision between an electromechanical integrated unit and a battery pack. [Solution] A second suspension member 30B in a vehicle undercarriage is fastened to a battery pack 10. A second mechanically and electrically integrated unit 20B is fastened to the second suspension member 30B. The second mechanically and electrically integrated unit 20B is disposed further outward from the vehicle outer end of the battery pack 10 in the vehicle length direction. The battery pack 10 and the second mechanically and electrically integrated unit 20B are disposed apart in the vehicle length direction.

Description

[Technical Field]

[0001] The present invention relates to a vehicle undercarriage. [Background technology]

[0002] Patent Document 1 discloses an undercarriage of an electric vehicle that includes a traction motor and a battery that supplies power to the traction motor. In the undercarriage, a suspension member that supports a suspension device is fastened to a battery protection frame that protects the battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-122993 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery that supplies power to the motor stores the electricity. The motor receives high-voltage power from the battery. In the event of a vehicle collision, it is necessary to protect not only the battery but also the motor. To achieve this, there is room for improvement in the undercarriage of electric vehicles. [Means for solving the problem]

[0005] A vehicle understructure for solving the above problems is a vehicle understructure for an electric vehicle in which drive wheels are driven by electric power stored in battery cells inside a battery pack. The electric vehicle includes the battery pack under a floor. The electric vehicle includes a mechanically and electrically integrated unit including a motor as a power source for driving the drive wheels and a power control device that supplies electric power to the motor. In this vehicle understructure, the mechanically and electrically integrated unit is fastened to a suspension member. In this vehicle understructure, the mechanically and electrically integrated unit is disposed outside the vehicle outer end of the battery pack in the vehicle length direction, the suspension member is fastened to the battery pack, and the battery pack and the mechanically and electrically integrated unit are disposed apart in the vehicle length direction. [Effects of the Invention]

[0006] The above vehicle undercarriage structure can reduce the possibility of a collision between the electromechanical integrated unit and the battery pack. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle underbody structure of an electric vehicle according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of an electrical system and a drive system in the electric vehicle shown in FIG. [Figure 3] FIG. 3 is an enlarged view showing the vehicle undercarriage structure at the rear of the electric vehicle shown in FIG. [Figure 4] 4 is a partial cross-sectional view of the vehicle undercarriage taken along line 4-4 passing through the center of the fastening member in FIG. [Figure 5] 5 is a cross-sectional view of the vehicle underbody structure taken along line 5-5 in FIG. 3, which passes through the center of the fastening member. [Figure 6] FIG. 6 is an enlarged view showing the vehicle undercarriage structure at the rear of the electric vehicle according to the second embodiment. [Figure 7] 7 is a cross-sectional view of the vehicle underbody structure taken along line 7-7 in FIG. 6, which passes through the center of the fastening member. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) The vehicle undercarriage structure according to the first embodiment will be described below with reference to Figures 1 to 5. In the following description, "front," "rear," "right," "left," "upper," and "lower" refer to the "front," "rear," "right," "left," "upper," and "lower" as seen by a passenger facing forward of the vehicle. The left-right direction coincides with the vehicle width direction.

[0009] As shown in FIG. 1, an electric vehicle 100 includes a battery pack 10 under a floor (not shown). The electric vehicle 100 includes front wheels 41, rear wheels 42, a first drive shaft 51, a second drive shaft 52, a first mechanical and electrical integrated unit 20A, a second mechanical and electrical integrated unit 20B, a first suspension member 30A, and a second suspension member 30B. The first mechanical and electrical integrated unit 20A and the second mechanical and electrical integrated unit 20B are disposed outside the vehicle from an outer end of the battery pack 10 in the vehicle length direction. The battery pack 10 and the first mechanical and electrical integrated unit 20A are disposed apart from each other in the vehicle length direction. The battery pack 10 and the second mechanical and electrical integrated unit 20B are disposed apart from each other in the vehicle length direction. A plurality of battery cells 14 are housed inside the battery pack 10. 1, 2, and 4, the plurality of battery cells 14 arranged in the battery pack 10 are shown collectively surrounded by dashed lines.

[0010] <Electrical system and drive system of electric vehicle 100> 2, the electric vehicle 100 includes a battery pack 10, a first mechanical and electrical integrated unit 20A, and a second mechanical and electrical integrated unit 20B. The first mechanical and electrical integrated unit 20A includes a first motor 21A and a first power control device 22A. The second mechanical and electrical integrated unit 20B includes a second motor 21B and a second power control device 22B.

[0011] The dashed lines in Fig. 2 indicate wire harnesses. The battery pack 10 and the first power control device 22A are electrically connected by a wire harness 60A. The first power control device 22A and the first motor 21A are electrically connected by a wire harness. The battery pack 10 and the second power control device 22B are electrically connected by a wire harness 60B. The second power control device 22B and the second motor 21B are electrically connected by a wire harness.

[0012] 1, a wire harness 60A that supplies power from the battery pack 10 to the first mechanical and electrical unit 20A is not arranged in the space between a central portion 11A, which is the front end of the battery pack 10 in the vehicle length direction, and the first mechanical and electrical unit 20A. A wire harness 60B that supplies power from the battery pack 10 to the second mechanical and electrical unit 20B is not arranged in the space between a central portion 11B, which is the rear end of the battery pack 10 in the vehicle length direction, and the second mechanical and electrical unit 20B.

[0013] The first motor 21A and the second motor 21B shown in FIG. 2 are power sources that drive the drive wheels. A plurality of battery cells 14 inside the battery pack 10 stores electric power to be supplied to the first motor 21A and the second motor 21B. The electric vehicle 100 drives the drive wheels using the electric power stored in the plurality of battery cells 14. The first motor 21A drives the front wheels 41 via a first drive shaft 51. In other words, the front wheels 41 are drive wheels. The second motor 21B drives the rear wheels 42 via a second drive shaft 52. In other words, the rear wheels 42 are drive wheels.

[0014] The first power control device 22A is a power control device that supplies power to the first motor 21A. The first power control device 22A includes an inverter that converts DC power from the multiple battery cells 14 into AC power and supplies it to the first motor 21A. The second power control device 22B is a power control device that supplies power to the second motor 21B. The second power control device 22B includes an inverter that converts DC power from the multiple battery cells 14 into AC power and supplies it to the second motor 21B.

[0015] <Regarding the vehicle undercarriage structure of the electric vehicle 100 in the area forward of the vehicle center> As shown in FIG. 1 , the battery pack 10 includes a first tapered portion 19A whose length in the vehicle width direction increases from the front in the vehicle length direction toward the center of the vehicle in a top view of the vehicle. The first tapered portion 19A includes a central portion 11A extending in the vehicle width direction. As described above, the central portion 11A is the front end of the battery pack 10 in the vehicle length direction. The first tapered portion 19A includes an inclined portion 15 and an inclined portion 16 that are inclined toward the outside in the vehicle width direction as they extend from the central portion 11A toward the rear in the vehicle length direction. The inclined portion 15 and the inclined portion 16 are connected to side surfaces of the battery pack 10. The inclined portion 15 is located to the right of the central portion 11A in the vehicle width direction. The inclined portion 16 is located to the left of the central portion 11A in the vehicle width direction.

[0016] The inclined portion 15 has a flange 15A extending outward in the vehicle length direction. The inclined portion 16 has a flange 16A extending outward in the vehicle length direction. The portion of the flange 15A indicated by the dashed line is located lower than the first suspension member 30A. The portion of the flange 16A indicated by the dashed line is located lower than the first suspension member 30A. The first suspension member 30A is fastened to the battery pack 10 at the flanges 15A and 16A. That is, the first suspension member 30A is fastened to the battery pack 10 at the inclined portions 15 and 16. The first suspension member 30A is fastened to the first electromechanical integrated unit 20A.

[0017] The electric vehicle 100 has a pair of left and right impact absorbing members 36 attached to the front ends of the first suspension member 30A. The electric vehicle 100 is provided with a bumper reinforcement 35 that spans the front ends of the pair of left and right impact absorbing members 36. The bumper reinforcement 35 extends in the vehicle width direction.

[0018] <Regarding the vehicle undercarriage structure of the electric vehicle 100 in the area rearward of the vehicle center> As shown in FIG. 1 , the battery pack 10 includes a second tapered portion 19B whose length in the vehicle width direction increases from the rear of the vehicle length direction toward the center of the vehicle in a top view of the vehicle. The second tapered portion 19B includes a central portion 11B extending in the vehicle width direction. As described above, the central portion 11B is the rear end of the battery pack 10 in the vehicle length direction. The second tapered portion 19B includes an inclined portion 17 and an inclined portion 18 that are inclined toward the outside in the vehicle width direction as they extend from the central portion 11B toward the front of the vehicle length direction. The inclined portion 17 and the inclined portion 18 are connected to the side surfaces of the battery pack 10. The inclined portion 17 is located to the right of the central portion 11B in the vehicle width direction. The inclined portion 18 is located to the left of the central portion 11A in the vehicle width direction.

[0019] The inclined portion 17 has a flange 17A extending outward in the vehicle length direction. The inclined portion 18 has a flange 18A extending outward in the vehicle length direction. The portion of the flange 17A indicated by the dashed line is located lower than the second suspension member 30B. The portion of the flange 18A indicated by the dashed line is located lower than the second suspension member 30B. The second suspension member 30B is fastened to the battery pack 10 at the flanges 17A and 18A. That is, the second suspension member 30B is fastened to the battery pack 10 at the inclined portions 17 and 18. The second suspension member 30B is fastened to the second mechanically and electrically integrated unit 20B.

[0020] <Method of fastening the second suspension member 30B and the battery pack 10> The following describes the manner in which the second suspension member 30B is fastened to the battery pack 10. The manner in which the first suspension member 30A is fastened to the battery pack 10 is the same as the manner in which the second suspension member 30B is fastened to the battery pack 10.

[0021] 3 is an enlarged view of the periphery of the second tapered portion 19B in FIG. 1. As shown in FIG. 3, the second suspension member 30B is composed of a side member 30BR and a side member 30BL. The side member 30BR is fastened to the second mechanically and electrically integrated unit 20B. The side member 30BL is fastened to the second mechanically and electrically integrated unit 20B. In other words, the second suspension member 30B and the second mechanically and electrically integrated unit 20B are integrated. Similarly, the first suspension member 30A and the first mechanically and electrically integrated unit 20A are integrated.

[0022] The length in the vehicle width direction of the central portion 11B is shorter than the sum of the vehicle width direction lengths of the surface 30BRS of the side member 30BR facing the battery pack 10, the surface 30BLS of the side member 30BL facing the battery pack 10, and the surface 20BS of the second mechanically and electrically integrated unit 20B facing the battery pack 10. In other words, the vehicle width direction length of the central portion 11B is shorter than the length of the portion of the second suspension member 30B extending in the vehicle width direction. Similarly, the vehicle width direction length of the central portion 11A shown in FIG. 1 is shorter than the length of the portion of the first suspension member 30A extending in the vehicle width direction.

[0023] The side member 30BR and the flange 17A are fastened together in the vehicle up-down direction by fastening members 32R. The side member 30BL and the flange 18A are fastened together in the vehicle up-down direction by fastening members 32L. That is, the second suspension member 30B and the flange 17A are fastened together in the vehicle up-down direction by fastening members 32R. The fastening members 32R are, for example, screws. The second suspension member 30B and the flange 18A are fastened together in the vehicle up-down direction by fastening members 32L. The fastening members 32L are, for example, screws.

[0024] <Method of fastening the side member 30BL and the battery pack 10> The following describes the manner in which the side member 30BL is fastened to the battery pack 10. Fig. 4 is a partial cross-sectional view of the vehicle undercarriage taken along line 4-4 in Fig. 3, which passes through the center of the fastening member 32L. Line 4-4 is a line perpendicular to the inclined portion 18. As shown in Fig. 4, the upper end of the flange 18A in the vehicle height direction is located lower than the upper end of the battery pack 10 in the vehicle height direction. The inclined portion 18 includes the flange 18A and a rising portion 18B that connects the upper surface of the flange 18A to the upper end of the battery pack 10. The side member 30BL, which is part of the second suspension member 30B, is disposed on the upper surface of the flange 18A in the vehicle height direction.

[0025] The side member 30BL has a through-hole 35L extending in the vehicle vertical direction. The side member 30BL and the flange 18A are fastened to each other by a fastening member 32L inserted into the through-hole 35L from above the vehicle. The side member 30BL is fastened to the battery pack 10 at the flange 18A. The flange 18A has a wall 13L that protrudes above the vehicle.

[0026] <Regarding the wall portion 13L provided on the flange portion 18A> 5 is a cross-sectional view of the vehicle undercarriage taken along line 5-5 in FIG. 3, which passes through the center of fastening member 32L. Line 5-5 is a straight line passing through wall 13L. Line 5-5 is a straight line perpendicular to line 4-4. As shown in FIG. 5, wall 13L faces side member 30BL. That is, wall 13L faces second suspension member 30B. Wall 13L is positioned so that, when fastening member 32L is released and second suspension member 30B moves toward battery pack 10, second suspension member 30B will contact wall 13L before contacting rising portion 18B shown in FIG. 4.

[0027] <Method of fastening side member 30BR and battery pack 10> The fastening configuration between the side member 30BR and the battery pack 10 is similar to the fastening configuration between the side member 30BL and the battery pack 10. That is, the inclined portion 17 includes a flange 17A and a rising portion that connects the upper surface of the flange 17A to the upper end of the battery pack 10. The side member 30BR, which is part of the second suspension member 30B, is disposed on the upper surface of the flange 17A in the vehicle height direction. The side member 30BR is provided with a through-hole that extends in the vehicle up-down direction. The side member 30BR and the flange 17A are fastened to each other by a fastening member 32R that is inserted through the through-hole from above the vehicle. The side member 30BR is fastened to the battery pack 10 at the flange 17A. The flange 17A is provided with a wall 13R that protrudes above the vehicle. The wall portion 13R is positioned so that when the fastening member 32R is released and the second suspension member 30B moves toward the battery pack 10, the second suspension member 30B will come into contact with the wall portion 13R before coming into contact with the rising portion of the inclined portion 17.

[0028] In this way, the second suspension member 30B is fastened to the battery pack 10 at the flange portions 17A and 18A. <Method of fastening the first suspension member 30A and the battery pack 10> The first suspension member 30A is fastened to the battery pack 10 in a manner similar to that of the second suspension member 30B and the battery pack 10. That is, the inclined portion 15 includes a flange 15A and a rising portion that connects from the upper surface of the flange 15A to the upper end of the battery pack 10. The inclined portion 16 includes a flange 16A and a rising portion that connects from the upper surface of the flange 16A to the upper end of the battery pack 10. The first suspension member 30A has a plurality of through holes that extend in the vehicle vertical direction. The first suspension member 30A is disposed on the upper surfaces of the flanges 15A and 16A in the vehicle height direction. The first suspension member 30A and the flange 15A are fastened to each other in the vehicle vertical direction by fastening members that are inserted into the through holes from above the vehicle. First suspension member 30A and flange 16A are fastened in the vehicle up-down direction by fastening members inserted through through holes from above the vehicle. Flanges 15A and 16A have walls that protrude above the vehicle. Each wall faces first suspension member 30A. Each wall is positioned so that, when the fastening members are released and first suspension member 30A moves toward battery pack 10, first suspension member 30A will come into contact with the respective wall before it comes into contact with the rising portions of inclined portion 15 and inclined portion 16.

[0029] <Operation of the First Embodiment> In the above vehicle undercarriage structure, the first mechanically and electrically integrated unit 20A and the battery pack 10 are integrated with a distance therebetween via the first suspension member 30A. Therefore, in the event of a collision, the distance between the first mechanically and electrically integrated unit 20A and the battery pack 10 is easily maintained. In the above vehicle undercarriage structure, the second mechanically and electrically integrated unit 20B and the battery pack 10 are integrated with a distance therebetween via the second suspension member 30B. Therefore, in the event of a collision, the distance between the second mechanically and electrically integrated unit 20B and the battery pack 10 is easily maintained.

[0030] <Effects of the first embodiment> (1-1) The above vehicle undercarriage structure can reduce the possibility of a collision between the first mechanically and electrically integrated unit 20A and the battery pack 10. The above vehicle undercarriage structure can reduce the possibility of a collision between the second mechanically and electrically integrated unit 20B and the battery pack 10.

[0031] (1-2) The second suspension member 30B and the second mechanically and electrically integrated unit 20B are disposed rearward of the battery pack 10. In a top view of the vehicle, the battery pack 10 has a second tapered portion 19B whose length in the vehicle width direction increases from the rear in the vehicle length direction toward the center of the vehicle. The second tapered portion 19B has a central portion 11B that is the rear end of the battery pack 10 in the vehicle length direction and extends in the vehicle width direction. The second tapered portion 19B has inclined portions 17 and 18 that are inclined toward the outside in the vehicle width direction as they extend forward in the vehicle length direction from the central portion 11B and connect to the side surfaces of the battery pack 10. The second suspension member 30B is fastened to the battery pack 10 at the inclined portions 17 and 18. According to the above configuration, as shown in FIG. 3 , when an impact is applied to the second suspension member 30B from the outside in the vehicle length direction, a force F_1 acts on the second suspension member 30B, moving the second suspension member 30B toward the center of the vehicle. The force F_1 is converted into a force F_2 acting in a direction along the inclined portion 17 and a force F_3 acting in a direction along the inclined portion 18, and these forces are released to the outside in the vehicle width direction. This reduces the impact transmitted from the second suspension member 30B to the battery pack 10. As a result, the above-described vehicle undercarriage structure can reduce the impact transmitted from the second suspension member 30B to the battery pack 10 when an impact is applied to the second suspension member 30B from the outside in the vehicle length direction.

[0032] (1-3) The first suspension member 30A and the first mechanically and electrically integrated unit 20A are disposed further forward in the vehicle than the battery pack 10. In a top view of the vehicle, the battery pack 10 has a first tapered portion 19A whose length in the vehicle width direction increases from the front in the vehicle length direction toward the center of the vehicle. The first tapered portion 19A has a central portion 11A that is the front end of the battery pack 10 in the vehicle length direction and extends in the vehicle width direction. The first tapered portion 19A has inclined portions 15 and 16 that are connected to the side surfaces of the battery pack 10 and are inclined to be positioned outward in the vehicle width direction as they extend from the central portion 11A toward the rear in the vehicle length direction. The first suspension member 30A is fastened to the battery pack 10 at the inclined portions 15 and 16. With the above configuration, a portion of an impact applied to the battery pack 10 from the front of the vehicle via the first suspension member 30A is dissipated outward in the vehicle width direction along the inclined portions 15 and 16. This reduces the impact transmitted from the first suspension member 30A to the battery pack 10. As a result, the above-described vehicle undercarriage structure can reduce the impact transmitted from the first suspension member 30A to the battery pack 10 when an impact is applied to the first suspension member 30A from the outside in the vehicle longitudinal direction.

[0033] (1-4) The inclined portion 17 includes a flange 17A extending outward in the vehicle length direction. The inclined portion 18 includes a flange 18A extending outward in the vehicle length direction. The upper end of the flange 17A in the vehicle height direction and the upper end of the flange 18A in the vehicle height direction are located lower than the upper end of the battery pack 10 in the vehicle height direction. A side member 30BR, which is a part of the second suspension member 30B, is disposed on the upper surface of the flange 17A in the vehicle height direction. A side member 30BL, which is a part of the second suspension member 30B, is disposed on the upper surface of the flange 18A in the vehicle height direction. Therefore, when the second suspension member 30B moves toward the battery pack 10, the second suspension member 30B comes into contact with the inclined portion 17 and the inclined portion 18 of the battery pack 10. This prevents the second mechanically and electrically integrated unit 20B and the battery pack 10 from becoming closer to each other. The above vehicle undercarriage structure can reduce the possibility of a collision between the second mechanically and electrically integrated unit 20B and the battery pack 10 when an impact is applied to the electric vehicle 100 from behind.

[0034] (1-5) The inclined portion 15 includes a flange 15A extending outward in the vehicle length direction. The inclined portion 16 includes a flange 16A extending outward in the vehicle length direction. The upper end of the flange 15A in the vehicle height direction and the upper end of the flange 16A in the vehicle height direction are located lower than the upper end of the battery pack 10 in the vehicle height direction. The first suspension member 30A is disposed on the upper surface of the flange 15A in the vehicle height direction. The first suspension member 30A is disposed on the upper surface of the flange 16A in the vehicle height direction. Therefore, when the first suspension member 30A moves toward the battery pack 10, the first suspension member 30A comes into contact with the inclined portion 15 and the inclined portion 16 of the battery pack 10. This prevents the first electromechanical integrated unit 20A and the battery pack 10 from becoming closer to each other. The vehicle undercarriage structure described above can reduce the possibility of a collision between the first mechanically and electrically integrated unit 20A and the battery pack 10 when an impact is applied from the front of the electric vehicle 100.

[0035] (1-6) The side member 30BL is provided with a through-hole 35L extending in the vehicle vertical direction. Similarly, the side member 30BR is provided with a through-hole extending in the vehicle vertical direction. The second suspension member 30B and the flange 18A are fastened in the vehicle vertical direction by a fastening member 32L inserted into the through-hole 35L from above the vehicle. The second suspension member 30B and the flange 17A are fastened in the vehicle vertical direction by a fastening member 32R inserted into the through-hole from above the vehicle. With the above configuration, it is possible to prevent the fastening member from dropping and thereby releasing the fastening between the second suspension member 30B and the battery pack 10.

[0036] (1-7) Like the second suspension member 30B, the first suspension member 30A is provided with a plurality of through holes extending in the vehicle vertical direction. The first suspension member 30A and the flange 15A are fastened together in the vehicle vertical direction by fastening members inserted into the through holes from above the vehicle. The first suspension member 30A and the flange 16A are fastened together in the vehicle vertical direction by fastening members inserted into the through holes from above the vehicle. With the above configuration, it is possible to prevent the fastening members from dropping and thereby causing the first suspension member 30A and the battery pack 10 to become detached.

[0037] (1-8) The flange 17A includes a wall 13R that protrudes upward above the vehicle. The flange 18A includes a wall 13L that protrudes upward above the vehicle. The wall 13R and the wall 13L face the second suspension member 30B. The wall 13R is positioned so that, when the fastening member 32R is released and the second suspension member 30B moves toward the battery pack 10, the second suspension member 30B comes into contact with the wall 13R before coming into contact with the rising portion of the inclined portion 17. The wall 13L is positioned so that, when the fastening member 32L is released and the second suspension member 30B moves toward the battery pack 10, the second suspension member 30B comes into contact with the wall 13L before coming into contact with the rising portion 18B. 3, when an impact is applied to the second suspension member 30B from the outside in the vehicle longitudinal direction, a force F_1 acts on the second suspension member 30B, moving the second suspension member 30B toward the vehicle center. When the second suspension member 30B moves toward the vehicle center, the second suspension member 30B comes into contact with the wall portion 13R provided on the flange portion 17A and the wall portion 13L provided on the flange portion 18A. The above-described vehicle undercarriage structure can prevent the second suspension member 30B from moving further toward the vehicle center.

[0038] (1-9) The flanges 15A and 16A have walls that protrude upward from the vehicle. Each wall faces the first suspension member 30A. Each wall is positioned so that when the fastening members are released and the first suspension member 30A moves toward the battery pack 10, the first suspension member 30A will contact the corresponding wall before the first suspension member 30A contacts the rising portion of the inclined portion 15 and the rising portion of the inclined portion 16. When an impact is applied to the first suspension member 30A from the outside in the vehicle longitudinal direction, a force acts on the first suspension member 30A to move the first suspension member 30A toward the center of the vehicle. When the first suspension member 30A moves toward the center of the vehicle, the first suspension member 30A comes into contact with the walls of the flanges 15A and 16A. According to the above vehicle undercarriage structure, the first suspension member 30A can be prevented from moving further toward the center of the vehicle.

[0039] <Modification of the first embodiment> The first embodiment can be modified as follows: The first embodiment described above and the following modifications of the first embodiment can be combined and implemented within the scope of technical compatibility.

[0040] The flange 17A in the vehicle undercarriage structure may not have the wall 13R. The flange 18A in the vehicle undercarriage structure may not have the wall 13L. Even if the flange 17A does not have the wall 13R and the flange 18A does not have the wall 13L, as long as the battery pack 10 in the vehicle undercarriage structure includes the flanges 17A and 18A, the possibility of a collision between the second mechanically and electrically integrated unit 20B and the battery pack 10 can be reduced when an impact is applied to the second suspension member 30B from the outside in the vehicle longitudinal direction. Similarly, the flange 15A in the vehicle undercarriage structure may not have a wall. The flange 16A in the vehicle undercarriage structure may not have a wall. Even if the flange portion 15A does not have a wall portion and the flange portion 16A does not have a wall portion, if the battery pack 10 is a vehicle undercarriage structure that has the flange portion 15A and the flange portion 16A, the possibility of a collision between the first mechanical and electrical integrated unit 20A and the battery pack 10 can be reduced when an impact is applied to the first suspension member 30A from the outside in the vehicle longitudinal direction.

[0041] (Second embodiment) The vehicle underbody structure according to the first embodiment will be described below with reference to Figures 6 and 7. The second embodiment will be described mainly focusing on the differences from the first embodiment.

[0042] In the second embodiment, as in the first embodiment, the manner in which the first suspension member 30A and the battery pack 10 are fastened together is the same as the manner in which the second suspension member 30B and the battery pack 10 are fastened together. Below, the manner in which the second suspension member 30B and the battery pack 10 are fastened together will be described as a representative example.

[0043] FIG. 6 is a schematic diagram showing the vehicle undercarriage structure at the rear of an electric vehicle 100 according to a second embodiment. The dashed lines in FIG. 6 indicate members that are provided below the second suspension member 30B. The side member 30BR has a protrusion 33R that extends downward in the vertical direction. The side member 30BL has a protrusion 33L that extends downward in the vertical direction. That is, the second suspension member 30B has a protrusion 33R and a protrusion 33L that extend downward in the vertical direction. A through hole 35R is provided in the protrusion 33R. A through hole 35L is provided in the protrusion 33L. The through holes 35R and 35L extend at an angle with respect to the vehicle length direction so that they are positioned outward in the vehicle width direction toward the center of the vehicle.

[0044] <Method of fastening the second suspension member 30B and the battery pack 10> Fig. 7 is a cross-sectional view of the vehicle undercarriage taken along line 7-7 in Fig. 6, which passes through the center of a fastening member 34L. As shown in Fig. 7, the side member 30BL has a through-hole 35L extending horizontally in the protruding portion 33L. That is, the second suspension member 30B has a through-hole 35L extending horizontally in the protruding portion 33L. The protruding portion 33L and the flange portion 18A are fastened together by a fastening member 34L inserted through the through-hole 35L. The fastening member 34L is, for example, a screw.

[0045] The fastening method between the side member 30BR and the battery pack 10 is similar to the fastening method between the side member 30BL and the battery pack 10. The side member 30BR has a through-hole 35R extending horizontally in the protrusion 33R. That is, the second suspension member 30B has a through-hole 35R extending horizontally in the protrusion 33R. The protrusion 33R and the flange 17A are fastened together by a fastening member 34R inserted through the through-hole 35R. The fastening member 34R is, for example, a screw. The side member 30BR is fastened to the battery pack 10 at the flange 17A. That is, the second suspension member 30B is fastened to the battery pack 10 at the flange 17A and the flange 18A.

[0046] <Method of fastening the first suspension member 30A and the battery pack 10> The first suspension member 30A is fastened to the battery pack 10 in a manner similar to that of fastening the second suspension member 30B to the battery pack 10. That is, the first suspension member 30A has two protrusions extending vertically downward. Each protrusion has a through-hole extending horizontally. The through-holes extend at an angle with respect to the vehicle length direction so that the through-holes are positioned outward in the vehicle width direction toward the center of the vehicle. One of the protrusions and the flange 15A are fastened together by a fastening member inserted through the through-hole. The other protrusion and the flange 16A are fastened together by a fastening member inserted through the through-hole.

[0047] <Operation of the Second Embodiment> When an impact is applied to the second suspension member 30B from the outside in the vehicle longitudinal direction, a horizontal force acts on the second suspension member 30B. If a horizontal force acts on the fastening member that fastens the second suspension member 30B and the battery pack 10 in the vertical direction, the fastening member may be sheared. When the fastening member 34R is inserted horizontally through the second suspension member 30B, the force acting in the direction shearing the fastening member 34R is smaller than when the fastening member 34R is inserted vertically through the second suspension member 30B. When the fastening member 34L is inserted horizontally through the second suspension member 30B, the force acting in the direction shearing the fastening member 34L is smaller than when the fastening member 34L is inserted vertically through the second suspension member 30B.

[0048] When an impact is applied to the first suspension member 30A from the outside in the vehicle longitudinal direction, a horizontal force acts on the first suspension member 30A. If a horizontal force acts on the fastening member that fastens the first suspension member 30A and the battery pack 10 in the vertical direction, the fastening member may be sheared. When the fastening member is inserted horizontally through the first suspension member 30A, the force applied in the direction that shears the fastening member is smaller than when the fastening member is inserted in the vertical direction of the vehicle through the first suspension member 30A.

[0049] <Effects of the second embodiment> (2-1) The above vehicle undercarriage structure can reduce the possibility that the fastening member 34R fastening the protrusion 33R and the flange 17A together will be sheared when an impact is applied from behind the electric vehicle 100. The above vehicle undercarriage structure can reduce the possibility that the fastening member 34L fastening the protrusion 33L and the flange 18A together will be sheared when an impact is applied from behind the electric vehicle 100. The above vehicle undercarriage structure can reduce the possibility that the fastening member fastening one of the protrusions provided on the first suspension member 30A and the flange 15A together will be sheared when an impact is applied from the front of the electric vehicle 100. The above vehicle undercarriage structure can reduce the possibility that the fastening member fastening the other protrusion provided on the first suspension member 30A and the flange 16A together will be sheared when an impact is applied from the front of the electric vehicle 100.

[0050] (2-2) The through holes 35R and 35L provided in the second suspension member 30B extend at an angle with respect to the vehicle length direction so as to be positioned outward in the vehicle width direction toward the vehicle center. As shown in FIG. 6 , a portion of a force F_1 applied to the battery pack 10 from the rear of the vehicle via the second suspension member 30B is converted into a force F_2 acting in a direction along the inclined portion 17 and a force F_3 acting in a direction along the inclined portion 18, and these force F_2 and F_3 are released outward in the vehicle width direction. The through holes 35R in the protrusions 33R extend at an angle with respect to the vehicle length direction so as to be positioned outward in the vehicle width direction toward the vehicle center. The through holes 35L in the protrusions 33L extend at an angle with respect to the vehicle length direction so as to be positioned outward in the vehicle width direction toward the vehicle center. According to the above configuration, when force F_2 is applied to fastening member 34R inserted through through hole 35R, the force acting in the direction shearing fastening member 34R is smaller than when fastening member 34R is inserted in the vehicle vertical direction. According to the above configuration, when force F_3 is applied to fastening member 34L inserted through through hole 35L, the force acting in the direction shearing fastening member 34L is smaller than when fastening member 34L is inserted in the vehicle vertical direction. The above vehicle undercarriage structure can further reduce the possibility of fastening member 34R and fastening member 34L being sheared during a collision.

[0051] (2-3) A portion of an impact applied to battery pack 10 from the front of the vehicle via first suspension member 30A is converted into a force acting in a direction along inclined portion 15 and a force acting in a direction along inclined portion 16, and is dissipated outward in the vehicle width direction. The through-holes in each of the convex portions of first suspension member 30A extend at an angle relative to the vehicle length direction so as to be positioned outward in the vehicle width direction toward the center of the vehicle. According to the above configuration, when a force is applied to a fastening member inserted through the through-hole in each of the convex portions of first suspension member 30A, the force acting in a direction that shears the fastening member is smaller than when the fastening member is inserted in the vertical direction of the vehicle. The above vehicle undercarriage structure further reduces the possibility of shearing the fastening member fastening first suspension member 30A to battery pack 10 during a collision.

[0052] <Modification of the second embodiment> The second embodiment can be modified as follows: The second embodiment described above and the following modifications of the second embodiment can be combined with each other to the extent that they are not technically inconsistent.

[0053] The second suspension member 30B does not have to have the protrusions 33R and 33L extending downwardly of the vehicle. The first suspension member 30A does not have to have any protrusions extending downwardly of the vehicle.

[0054] The second suspension member 30B and the flange 17A do not have to be fastened together by fastening members 34R that are inserted horizontally. For example, the second suspension member 30B and the flange 17A may be fastened together by fastening members 34R that are inserted in the vehicle up-and-down direction. Similarly, the second suspension member 30B and the flange 18A do not have to be fastened together by fastening members 34L that are inserted horizontally. For example, the second suspension member 30B and the flange 18A may be fastened together by fastening members 34L that are inserted in the vehicle up-and-down direction.

[0055] The through-holes 35L formed in the second suspension member 30B do not have to be inclined with respect to the vehicle length direction so that they are positioned more outward in the vehicle width direction toward the vehicle center, as long as they extend horizontally. The through-holes 35R formed in the second suspension member 30B do not have to be inclined with respect to the vehicle length direction so that they are positioned more outward in the vehicle width direction toward the vehicle center, as long as they extend horizontally. Similarly, the through-holes formed in the first suspension member 30A do not have to be inclined with respect to the vehicle length direction so that they are positioned more outward in the vehicle width direction toward the vehicle center, as long as they extend horizontally.

[0056] <Other change examples> Other elements that can be modified in common to the above embodiments include the following: The following modifications can be implemented in combination with each other to the extent that they are not technically inconsistent.

[0057] The length in the vehicle width direction of central portion 11A may be longer than the length of the portion of first suspension member 30A extending in the vehicle width direction. The length in the vehicle width direction of central portion 11B may be longer than the length of the portion of second suspension member 30B extending in the vehicle width direction.

[0058] The fastening members for fastening the first suspension member 30A and the battery pack 10 together are not limited to screws. For example, the first suspension member 30A and the battery pack 10 may be fastened together with fastening members made of bolts and nuts. The fastening members for fastening the second suspension member 30B and the battery pack 10 are not limited to screws. For example, the second suspension member 30B and the battery pack 10 may be fastened together with fastening members made of bolts and nuts.

[0059] <Example of changes to the flange> The inclined portion 15 of the battery pack 10 does not have to have the flange portion 15A. The inclined portion 16 of the battery pack 10 does not have to have the flange portion 16A. If the first suspension member 30A is fastened to the inclined portions 15 and 16 of the battery pack 10 and the first mechanically and electrically integrated unit 20A is fastened to the first suspension member 30A, the possibility of a collision between the first mechanically and electrically integrated unit 20A and the battery pack 10 can be reduced when an impact is applied from the outside in the vehicle longitudinal direction.

[0060] The inclined portion 17 of the battery pack 10 does not have to have the flange portion 17A. The inclined portion 18 of the battery pack 10 does not have to have the flange portion 18A. If the second suspension member 30B is fastened to the inclined portions 17 and 18 of the battery pack 10 and the second mechanically and electrically integrated unit 20B is fastened to the second suspension member 30B, the possibility of a collision between the second mechanically and electrically integrated unit 20B and the battery pack 10 can be reduced when an impact is applied from the outside in the vehicle longitudinal direction.

[0061] <Example of changes to the tapered section> The battery pack 10 in the vehicle undercarriage may include only the first tapered portion 19A of the first tapered portion 19A and the second tapered portion 19B. The battery pack 10 may include only the second tapered portion 19B of the first tapered portion 19A and the second tapered portion 19B. The battery pack 10 in the vehicle undercarriage may not include the first tapered portion 19A and the second tapered portion 19B. For example, in a vehicle undercarriage in which a first suspension member 30A is fastened to the battery pack 10, a first mechanically and electrically integrated unit 20A is fastened to the first suspension member 30A, and the battery pack 10 and the first mechanically and electrically integrated unit 20A are arranged apart in the vehicle length direction, the possibility of a collision between the first mechanically and electrically integrated unit 20A and the battery pack 10 can be reduced. For example, in a vehicle undercarriage structure in which a second suspension member 30B is fastened to the battery pack 10, a second mechanical and electrical integrated unit 20B is fastened to the second suspension member 30B, and the battery pack 10 and the second mechanical and electrical integrated unit 20B are arranged at a distance in the vehicle length direction, the possibility of a collision between the second mechanical and electrical integrated unit 20B and the battery pack 10 can be reduced.

[0062] <Combination of the First and Second Embodiments> In the vehicle undercarriage structure of the first embodiment, both the first suspension member 30A and the second suspension member 30B have through holes extending in the vehicle up-down direction. In the vehicle undercarriage structure of the second embodiment, both the first suspension member 30A and the second suspension member 30B have through holes extending in the horizontal direction. The extending direction of the through holes of the first suspension member 30A and the second suspension member 30B may be changed as appropriate. For example, if the first suspension member 30A has a through hole extending in the vehicle up-down direction, the second suspension member 30B may have a through hole extending in the horizontal direction. For example, the second suspension member 30B may have a through hole 35L extending in the vehicle up-down direction and a through hole 35R extending in the horizontal direction.

[0063] In a vehicle understructure in which the first suspension member 30A is fastened to the battery pack 10, the first mechanical and electrical integrated unit 20A is fastened to the first suspension member 30A, and the battery pack 10 and the first mechanical and electrical integrated unit 20A are disposed apart in the vehicle longitudinal direction, the second suspension member 30B does not have to be fastened to the battery pack 10. In a vehicle understructure in which the first suspension member 30A is fastened to the battery pack 10, the first mechanical and electrical integrated unit 20A is fastened to the first suspension member 30A, and the battery pack 10 and the first mechanical and electrical integrated unit 20A are disposed apart in the vehicle longitudinal direction, the second suspension member 30B does not have to be fastened to the second suspension member 30B. In a vehicle undercarriage structure in which a first suspension member 30A is fastened to the battery pack 10, a first mechanical and electrical integrated unit 20A is fastened to the first suspension member 30A, and the battery pack 10 and the first mechanical and electrical integrated unit 20A are arranged at a distance in the vehicle length direction, the battery pack 10 and the second mechanical and electrical integrated unit 20B do not need to be arranged at a distance in the vehicle length direction.

[0064] In a vehicle understructure in which the second suspension member 30B is fastened to the battery pack 10, the second mechanical and electrical integrated unit 20B is fastened to the second suspension member 30B, and the battery pack 10 and the second mechanical and electrical integrated unit 20B are disposed apart in the vehicle longitudinal direction, the first suspension member 30A does not have to be fastened to the battery pack 10. In a vehicle understructure in which the second suspension member 30B is fastened to the battery pack 10, the second mechanical and electrical integrated unit 20B is fastened to the second suspension member 30B, and the battery pack 10 and the second mechanical and electrical integrated unit 20B are disposed apart in the vehicle longitudinal direction, the first mechanical and electrical integrated unit 20A does not have to be fastened to the first suspension member 30A. In a vehicle undercarriage structure in which a second suspension member 30B is fastened to the battery pack 10, a second mechanical and electrical integrated unit 20B is fastened to the second suspension member 30B, and the battery pack 10 and the second mechanical and electrical integrated unit 20B are arranged at a distance in the vehicle length direction, the battery pack 10 and the first mechanical and electrical integrated unit 20A do not need to be arranged at a distance in the vehicle length direction.

[0065] <Additional Notes> The technical ideas that can be understood from the above-described embodiment and modified examples will be described. [Appendix 1] A vehicle understructure for an electric vehicle in which drive wheels are driven by electricity stored in battery cells inside a battery pack, the electric vehicle having the battery pack under its floor and an electromechanical integrated unit consisting of a motor that is a power source for driving the drive wheels and a power control device that supplies electricity to the motor, the electromechanical integrated unit fastened to a suspension member, the electromechanical integrated unit arranged outside the vehicle on the outer end of the battery pack in the vehicle length direction, the suspension member fastened to the battery pack, and the battery pack and the electromechanical integrated unit arranged at a distance in the vehicle length direction.

[0066] [Appendix 2] The suspension member and the electromechanical integrated unit are disposed rearward of the battery pack, and in a top view of the vehicle, the battery pack has a tapered portion whose length in the vehicle width direction increases from the rear in the vehicle length direction toward the center of the vehicle, and the tapered portion has a central portion that is the rear end of the battery pack in the vehicle length direction and extends in the vehicle width direction, and two inclined portions that are inclined so as to be positioned outward in the vehicle width direction as they extend from the central portion toward the front in the vehicle length direction and are connected to side surfaces of the battery pack, 2. The vehicle undercarriage structure according to claim 1, wherein the suspension member is fastened to the battery pack at the inclined portion.

[0067] [Appendix 3] A vehicle undercarriage structure as described in Appendix 1, wherein the suspension member and the electromechanical integrated unit are disposed forward of the battery pack, and when viewed from above the vehicle, the battery pack has a tapered portion whose length in the vehicle width direction increases from the front in the vehicle length direction toward the center of the vehicle, and the tapered portion has a central portion that is the front end of the battery pack in the vehicle length direction and extends in the vehicle width direction, and two inclined portions that are inclined to be positioned outward in the vehicle width direction as they extend from the central portion toward the rear in the vehicle length direction and are connected to side surfaces of the battery pack, and the suspension member is fastened to the battery pack at the inclined portions.

[0068] [Appendix 4] The suspension member includes a first suspension member and a second suspension member, and the electromechanical integrated unit includes a first electromechanical integrated unit and a second electromechanical integrated unit, the first suspension member and the first electromechanical integrated unit are disposed forward of the battery pack, and in a top view of the vehicle, the battery pack includes a first tapered portion whose length in the vehicle width direction increases from the front in the vehicle length direction toward the center of the vehicle, the first tapered portion including: a central portion that is the front end of the battery pack in the vehicle length direction and extends in the vehicle width direction; and two inclined portions that are inclined so as to be positioned outward in the vehicle width direction as they extend from the central portion toward the rear in the vehicle length direction and are connected to side surfaces of the battery pack, 10. A vehicle undercarriage structure as described in Appendix 1, wherein the first suspension member is fastened to the battery pack at the inclined portion, the second suspension member and the second mechanical and electrical integrated unit are arranged rearward of the battery pack, and when viewed from above the vehicle, the battery pack has a second tapered portion whose length in the vehicle width direction increases from the rear of the vehicle length direction toward the center of the vehicle, and the second tapered portion has a central portion that is the rear end of the battery pack in the vehicle length direction and extends in the vehicle width direction, and two inclined portions that are inclined to be positioned outward in the vehicle width direction as they extend from the central portion toward the front of the vehicle length direction and connect to side surfaces of the battery pack, and the first suspension member is fastened to the battery pack at the inclined portions.

[0069] [Appendix 5] A vehicle undercarriage structure as set forth in any one of Appendices 2 to 4, wherein the inclined portion has a flange portion extending outward in the vehicle length direction, the upper end of the flange portion in the vehicle height direction is located lower than the upper end of the battery pack in the vehicle height direction, and a portion of the suspension member is disposed on the upper surface of the flange portion in the vehicle height direction.

[0070] [Appendix 6] A vehicle undercarriage structure as described in Appendix 5, wherein the suspension member has a through hole extending in the vertical direction of the vehicle, and the suspension member and the flange portion are fastened together by a fastening member inserted from above the vehicle into the through hole extending in the vertical direction of the vehicle.

[0071] [Appendix 7] A vehicle undercarriage structure as described in Appendix 5 or Appendix 6, wherein the suspension member has a convex portion extending vertically downward, the convex portion has a through hole extending horizontally, and the convex portion and the flange portion are fastened together by a fastening member inserted into the through hole extending horizontally provided in the convex portion.

[0072] [Appendix 8] A vehicle undercarriage structure as described in Appendix 7, wherein the horizontally extending through holes provided in the convex portion extend at an angle relative to the vehicle length direction so as to be positioned further outward in the vehicle width direction as they approach the center of the vehicle.

[0073] [Appendix 9] A vehicle undercarriage structure as set forth in any one of Appendices 6 to 8, wherein the inclined portion has a rising portion that connects from the upper surface of the flange portion to the upper end of the battery pack, the flange portion has a wall portion that protrudes above the vehicle, the wall portion faces the suspension member, and is positioned so that when the fastening member is released and the suspension member moves toward the battery pack, the suspension member will contact the wall portion before contacting the rising portion. [Explanation of symbols]

[0074] 10. Battery pack 14...Battery cell 15, 16, 17, 18...Slope part 18B...Rising part 20A...1st mechanical and electrical integrated unit 20B: Second mechanical and electrical integrated unit 30A...First suspension member 30B...Second suspension member 100...Electric vehicles 11A, 11B...Central part 13L, 13R…Wall part 15A, 16A, 17A, 18A...Trim section 19A...First tapered section 19B...Second tapered section 32L, 32R... Fastening members 33L, 33R...Convex part 34L, 34R... Fastening members 35L, 35R…Through hole

Claims

1. A vehicle underbody structure for an electric vehicle in which drive wheels are driven by electric power stored in battery cells inside a battery pack, The electric vehicle includes: The battery pack is provided under a floor, a mechanically and electrically integrated unit including a motor that is a power source for driving the drive wheels and a power control device that supplies power to the motor; The electromechanical integrated unit is fastened to a suspension member, the electromechanical integrated unit is disposed on the outer side of the vehicle than the outer end of the battery pack in the vehicle length direction, the suspension member is fastened to the battery pack; The battery pack and the electromechanical integrated unit are disposed apart from each other in the vehicle length direction. Vehicle undercarriage.

2. the suspension member and the electromechanical integrated unit are disposed rearward of the battery pack, When viewed from above the vehicle, the battery pack has a tapered portion whose length in a vehicle width direction increases from the rear in a vehicle length direction toward the center of the vehicle, the tapered portion includes a central portion that is a rear end of the battery pack in the vehicle length direction and extends in the vehicle width direction, and two inclined portions that are inclined from the central portion toward the front in the vehicle length direction so as to be positioned outward in the vehicle width direction and are connected to side surfaces of the battery pack, The suspension member is fastened to the battery pack at the inclined portion. The vehicle undercarriage structure according to claim 1.

3. the suspension member and the electromechanical integrated unit are disposed forward of the battery pack, When viewed from above the vehicle, the battery pack has a tapered portion whose length in a vehicle width direction increases from the front in a vehicle length direction toward the center of the vehicle, the tapered portion includes a central portion that is a front end of the battery pack in the vehicle length direction and extends in the vehicle width direction, and two inclined portions that are inclined from the central portion toward the rear in the vehicle length direction so as to be positioned outward in the vehicle width direction and are connected to side surfaces of the battery pack, The suspension member is fastened to the battery pack at the inclined portion. The vehicle undercarriage structure according to claim 1.

4. the inclined portion includes a flange portion extending outward in the vehicle length direction, an upper end of the flange portion in a vehicle height direction is located lower than an upper end of the battery pack in the vehicle height direction; A part of the suspension member is disposed on an upper surface of the flange in the vehicle height direction. The vehicle underbody structure according to claim 2 or 3.

5. The suspension member is provided with a through hole extending in the vehicle vertical direction, The suspension member and the flange are fastened together by a fastening member inserted into the through hole from above the vehicle. The vehicle underbody structure according to claim 4.

6. the suspension member includes a convex portion extending vertically downward, a through hole extending horizontally is provided in the protrusion, The protrusion and the flange are fastened together by a fastening member inserted into the through hole. The vehicle underbody structure according to claim 4.

7. The through-hole extends at an angle with respect to the vehicle length direction so as to be positioned outward in the vehicle width direction toward the center of the vehicle. The vehicle underbody structure according to claim 6.

8. the inclined portion includes a rising portion that connects from an upper surface of the flange portion to an upper end of the battery pack, The flange portion includes a wall portion protruding upward from the vehicle, the wall portion faces the suspension member, When the fastening member is released and the suspension member moves toward the battery pack, the suspension member is disposed at a position where the suspension member comes into contact with the wall portion before coming into contact with the rising portion. The vehicle underbody structure according to claim 5.

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