Electric vehicle rear part structure

Abstract

To improve rigidness of a floor part on which a spare tire is installed, and improve fitting rigidity of the spare tire.SOLUTION: An electric vehicle rear part structure has a holding bracket 20 which is provided on a floor part positioned on a vehicle rear side of a battery pack, and holds a spare tire. The holding bracket 20 has: a holding part 21 which holds a midship part of the spare tire; a front side wall part 22 which extends to a front side from the holding part 21, and of which a front end is joined to the floor part; outer side wall parts 23, 24 which extend to both outer sides from the holding part 21, and of which side ends are joined to the floor part; and reinforcement wall parts 25, 26 which connect the front side wall part 22 and both outer side wall parts 23, 24.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a rear structure of an electric vehicle. [Background technology]

[0002] A battery pack is disposed below the floor of an electric vehicle. The battery pack is a generally rectangular parallelepiped device that has a predetermined dimension in the vehicle width direction and extends in the vehicle longitudinal direction, and supplies power to, for example, a drive motor disposed in the front of the vehicle. The rear of the electric vehicle must be rigid and strong enough to withstand impact loads such as those caused by a rear-end collision. In an electric vehicle having a battery pack, the rear of the floor must be rigid and strong enough to protect the battery pack when subjected to an impact load such as a rear-end collision.

[0003] Also, as disclosed in Patent Document 1, there is known a vehicle that has a tire storage section in the rear of the vehicle that can store a spare tire. In a structure in which a spare tire is mounted in the rear of an electric vehicle, the tire storage section is located behind the battery pack, for example, in the bottom of the luggage compartment. Here, in the structure disclosed in Patent Document 1, the spare tire is stored in an inclined position rather than horizontally in order to prevent an increase in the vehicle's longitudinal dimensions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-114139 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in an electric vehicle with a spare tire stored in the rear of the vehicle, as in the structure of the above example, if the vehicle receives an impact load from the rear of the vehicle, the tire storage compartment may be deformed. In this example, the bottom of the tire storage compartment is formed by the rear floor. If the rear floor is deformed, the spare tire may move forward of the vehicle and come into contact with components located in front of the spare tire.

[0006] In this example, the spare tire is stored in an inclined position, so if the spare tire moves forward of the vehicle due to a rear-end collision or the like, the wheel located in the radial center of the spare tire may come into contact with components located in front of the spare tire.In this example, the spare tire is installed in an inclined position, so the wheel may come into contact with components located in front of the spare tire.Furthermore, if the spare tire moves forward, the spare tire may come into contact with the battery pack.

[0007] In the above example, the bracket installed in the tire storage compartment has a pipe-shaped frame and a plate-shaped tire mounting portion. Impact loads, such as those from a rear-end collision, can cause the bracket to deform. If the bracket deforms, the spare tire's position cannot be maintained, and the spare tire may move forward.

[0008] Therefore, the structure of the above example leaves room for improvement in terms of ensuring the support rigidity to support the spare tire against impact loads such as in a rear-end collision and preventing the spare tire from coming into contact with the battery pack.

[0009] The present invention has been made to solve the above-mentioned problems, and its object is to provide a rear structure for an electric vehicle that can improve the rigidity of the floor portion on which a spare tire is installed and can also improve the mounting rigidity of the spare tire. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a rear structure for an electric vehicle, comprising: a battery pack disposed below a floor portion of the vehicle; and a retaining bracket provided on the floor portion located rearward of the battery pack and configured to hold a spare tire, the spare tire being held by the retaining bracket in a state inclined downward as it approaches the rear of the vehicle, and an upper end of a front portion of an outer peripheral surface of the spare tire being positioned higher than an upper end of a rear portion of the battery pack in the vehicle vertical direction. In the rear structure for an electric vehicle, the retaining bracket has a retaining portion disposed above the floor portion with a space therebetween and configured to hold a radial center portion of the spare tire, a front wall portion extending from the retaining portion toward the front of the vehicle and having a front end joined to the floor portion, outer wall portions extending from the retaining portion to both outer sides in the vehicle width direction and having side ends joined to the floor portion, and reinforcing wall portions connecting the front wall portion to the outer wall portions on both sides. [Effects of the Invention]

[0011] According to the present invention, in a rear structure of an electric vehicle, it is possible to improve the rigidity of the floor portion on which a spare tire is placed and also improve the mounting rigidity of the spare tire. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a plan view showing an embodiment of a rear structure for an electric vehicle according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 3] 2 is a perspective view of the vehicle shown in FIG. 1 with the spare tire and back panel removed, viewed from above and from the front side. FIG. [Figure 4] FIG. 4 is a top view of FIG. [Figure 5] 5 is a top view showing a state in which the holding bracket of FIG. 4 has been removed. [Figure 6] 4 is a rear view of the retaining bracket and the like in FIG. 3 as viewed from the rear side of the vehicle. [Figure 7] FIG. 5 is a cross-sectional view taken along the line BB in FIG. 4. [Figure 8]FIG. 5 is a cross-sectional view taken along the line CC in FIG. 4. [Figure 9] FIG. 8 is a cross-sectional view taken along the line DD in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, one embodiment of a rear structure for an electric vehicle according to the present invention will be described with reference to the drawings (Figs. 1 to 9). In the drawings, the direction of the arrow Fr indicates the front in the longitudinal direction of the vehicle. In the description of the embodiment, the "front (front end) and rear (rear end)" correspond to the front and rear in the longitudinal direction of the vehicle. Furthermore, the arrows R and L indicate the right and left sides when a passenger looks forward of the vehicle. Furthermore, the arrow U indicates the upward direction in the vertical direction of the vehicle.

[0014] As shown in Figures 1 and 2, the rear structure of an electric vehicle of this embodiment has a battery pack 1 (Figure 2) arranged below the floor of the vehicle, and a holding bracket 20 provided on the floor located on the vehicle rear side of the battery pack 1 and holding a spare tire 5, with the spare tire 5 being held by the holding bracket 20 in a state inclined downward toward the rear of the vehicle. In addition, the upper end of the front part of the outer circumferential surface part (tread part 5a) of the spare tire 5 is arranged above the upper end of the rear part of the battery pack 1 in the vehicle vertical direction. The rear structure will be described in detail below.

[0015] The electric vehicle of this embodiment is a type of vehicle in which a passenger compartment for passengers and a luggage compartment located behind the passenger compartment constitute a single vehicle compartment. The vehicle rear structure of this embodiment is provided with a tire storage section 12 capable of storing a spare tire 5 on the floor of the luggage compartment. The rear structure of this embodiment has rear side members 2, a back panel 3, a rear floor panel 10, and the above-mentioned retaining bracket 20. The members will be described below.

[0016] As shown in Figures 3 to 6, the rear side members 2 are disposed on both outer sides in the vehicle width direction at the rear of the vehicle and extend in the vehicle longitudinal direction. The rear side members 2 are highly rigid members that constitute the vehicle body frame and are made of a metal material. The rear side member 2 of this embodiment has a main body portion 2a (Figure 6) that has a substantially U-shaped cross section with an opening at the top, and a lid portion 2b that covers the opening of the main body portion 2a.

[0017] As shown in Fig. 6, a flange 2c is formed at the upper end of the main body 2a, and the outer portion of the rear floor panel 10 in the vehicle width direction is joined to the flange 2c by spot welding or the like. As shown in Figs. 3 to 5, the lid portion 2b and the outer portion of the rear floor panel 10 in the vehicle width direction are preferably arranged so as to be continuous.

[0018] As shown in Figures 1 and 2, the back panel 3 is disposed at the rear end of the vehicle body and has a front surface 3a facing the front of the vehicle and a rear surface 3b facing the rear of the vehicle. In this example, the rear ends of the rear side members 2 are joined to the outer portions of the front surface 3a of the back panel 3 in the vehicle width direction, and the rear end of the rear floor panel 10 is joined to the middle portion of the back panel 3 in the vehicle width direction. The upper portion of the back panel 3 forms, for example, the lower portion of a back door opening (not shown). In addition, a plastic rear bumper (not shown) or the like is attached to the rear side of the back panel 3.

[0019] As shown in Figures 1 and 2, the rear floor panel 10 is one of the components constituting the floor portion located at the rear of the vehicle, and is disposed, for example, behind a rear seat (not shown). The rear floor panel 10 of this embodiment is disposed on the floor portion of a luggage compartment in the vehicle cabin. The rear floor panel 10 has an outer peripheral surface portion 11 and a tire storage portion 12. Each portion will be described below.

[0020] 3 to 5, the outer peripheral surface portion 11 of this embodiment is located at the front and outer sides of the rear floor panel 10 in the vehicle width direction, and has a U-shape with an open rear when viewed from above. The outer peripheral surface portion 11 of this example has a front outer peripheral surface portion 11a located at the front of the rear floor panel 10, and outer outer peripheral surface portions 11b, 11c located at the outer sides of the rear floor panel 10 in the vehicle width direction. The front outer peripheral surface portion 11a and the left and right outer outer peripheral surface portions 11b, 11c form the U-shape as described above.

[0021] The front outer peripheral surface portion 11a extends in the vehicle width direction. The front end of the front outer peripheral surface portion 11a may be joined to, for example, the rear portion of the front floor panel. The outer portion of the front outer peripheral surface portion 11a in the vehicle width direction is joined to the inner end of the rear side member 2 in the vehicle width direction. As shown in FIG. 4, a cross member 4 extending in the vehicle width direction is joined to the underside of the front outer peripheral surface portion 11a. The cross member 4 is a highly rigid member that constitutes the vehicle body frame, similar to the rear side member 2, and is made of a metal material. The outer portion of the cross member 4 in the vehicle width direction is joined to the inner portion of the rear side member 2 in the vehicle width direction by spot welding.

[0022] The outer outer peripheral surface portions 11b, 11c extend rearward from the outer side in the vehicle width direction at the rear of the front outer peripheral surface portion 11a and are joined to the front surface 3a of the back panel 3. The outer end portions in the vehicle width direction of the outer outer peripheral surface portions 11b, 11c are joined to the inner end of the rear side member 2. The inner end portion in the vehicle width direction of the outer outer peripheral surface portion 11b has a curved shape that is recessed toward the outside of the vehicle. This curved shape corresponds to the curved shapes of the upper ends of a left side wall portion 18 and a right side wall portion 19 of the tire storage portion 12, which will be described later.

[0023] Next, the tire storage section 12 will be described. As shown in Figures 3 and 6, the tire storage section 12 is located in the middle of the rear floor panel 10 in the vehicle width direction, and is a portion recessed downward from the upper surface of the outer peripheral surface section 11. The tire storage section 12 is located rearward of the front outer peripheral surface section 11a and between the left and right outer outer peripheral surface sections 11b, 11c.

[0024] 2, when the spare tire 5 is stored in the tire storage section 12, the front portion of the tread portion 5a of the spare tire 5 is inclined so as to be positioned higher than the rear portion. That is, the spare tire 5 is disposed so as to be inclined downward toward the rear of the vehicle when viewed in the vehicle width direction.

[0025] The tire storage section 12 of this embodiment has bottom sections 14, 17, a left side wall section 18, and a right side wall section 19. Each section will be described below.

[0026] As shown in FIGS. 3, 6, and 8, the bottom portions 14, 17 of the tire storage compartment 12 have an inclined portion 14 and a flat portion 17. The inclined portion 14 is a portion that extends from the rear end of the front outer peripheral surface portion 11a toward the rear of the vehicle, sloping downward. The flat portion 17 is a substantially flat portion that extends horizontally toward the rear of the vehicle from the rear end of the inclined portion 14. As shown in FIGS. 3 and 6, a flange 17a is provided at the rear end of the flat portion 17, protruding upward from the rear end. The flange 17a is joined to the lower part of the front surface 3a of the back panel 3 by spot welding or the like. A retaining bracket 20 for holding the spare tire 5 is joined to the inclined portion 14 of the bottom. Details of the retaining bracket 20 will be described later.

[0027] The left side wall 18 is a wall extending downward from the inner end of the left outer peripheral surface 11b in the vehicle width direction toward the bottom. The left side wall 18 has a left curved portion 18a and a left vertical wall portion 18b. The inner wall of the left curved portion 18a is curved so as to be recessed outward in the vehicle width direction. As shown in FIG. 1, the left curved portion 18a corresponds to the curved shape of the tread portion 5a of the spare tire 5. In other words, when the spare tire 5 is stored in the tire storage portion 12, the left curved portion 18a is configured to cover the tread portion 5a of the spare tire 5 from the radially outer side of the spare tire 5.

[0028] The left vertical wall portion 18b extends rearward from the rear end of the left curved portion 18a. The rear end of the left vertical wall portion 18b is joined to the back panel 3. For example, the rear end of the left vertical wall portion 18b extends in the vertical direction of the vehicle, and as shown in Fig. 6, a flange 18c is formed at the rear end so as to protrude outward in the vehicle width direction, and the flange 18c is joined to the front surface 3a of the back panel 3 by spot welding or the like.

[0029] The right side wall portion 19 is a wall portion extending downward from the inner end of the right outer peripheral surface portion 11c in the vehicle width direction toward the bottom. Similar to the left side wall portion 18, the right side wall portion 19 has a right curved portion 19a and a right vertical wall portion 19b. The right curved portion 19a is a wall portion formed to be bilaterally symmetrical with the left curved portion 18a. That is, the inner wall of the right curved portion 19a is curved so as to be recessed outward in the vehicle width direction. The right curved portion 19a corresponds to the curved shape of the tread portion 5a of the spare tire 5. The right curved portion 19a is configured to cover the tread portion 5a of the spare tire 5 from the radially outer side of the spare tire 5 when the spare tire 5 is stored in the tire storage portion 12.

[0030] The right vertical wall portion 19b extends rearward from the rear end of the right curved portion 19a. Similar to the left vertical wall portion 18b, the rear end of the right vertical wall portion 19b is joined to the back panel 3. The rear end of the right vertical wall portion 19b extends in the vertical direction of the vehicle, and a flange 19c that protrudes outward in the vehicle width direction is formed at the rear end, and the flange 19c is joined to the front surface 3a of the back panel 3 by spot welding or the like.

[0031] Next, the retaining bracket 20 will be described. The retaining bracket 20 is a bracket that holds the inclined spare tire 5 as described above, and is a highly rigid member made of a metal material. The retaining bracket 20 is joined to the inclined portion 14 at the bottom of the tire storage section 12, and has a retaining portion 21, a front wall portion 22, outer wall portions 23 and 24, and reinforcing wall portions 25 and 26, as shown in FIGS. 3 and 4 .

[0032] The retaining portion 21 is disposed above the floor portion with a gap therebetween and retains the radial center of the spare tire 5. The front wall portion 22 extends from the retaining portion 21 toward the front of the vehicle, with its front end joined to the floor portion. The outer wall portions 23, 24 extend from the retaining portion 21 to both outer sides in the vehicle width direction, with their side ends joined to the floor portion. The reinforcing wall portions 25, 26 connect the front wall portion 22 to the outer wall portions 23, 24 on both sides. In addition, the retaining bracket 20 is formed with radial beads 22a, 23a, 24a that extend radially from the retaining portion 21 toward the front end of the front wall portion 22 and the front ends of the outer wall portions 23, 24 on both sides.

[0033] The retaining bracket 20 of this embodiment has a generally semiconical shape with the retaining portion 21 at its apex, and has a generally semicircular outline when viewed from above. In other words, the retaining bracket 20 has a shape like a cone with the rear portion cut off. The rear end of the retaining bracket 20 extends substantially vertically.

[0034] As shown in FIG. 2 , the holding portion 21 is a plate-shaped portion that is disposed above the vehicle with a gap between it and the intermediate portion of the inclined portion 14 at the bottom of the tire storage portion 12 in the vehicle longitudinal direction. In this example, the holding portion 21 is plate-shaped and parallel to the inclined portion 14. Furthermore, a protruding portion that protrudes upward is provided at the rear of the holding portion 21, at the center in the vehicle width direction, and the tip of the protruding portion forms a flat surface that is parallel to the inclined portion 14. A through-hole 21a is formed in the center of the protruding portion, and a cylindrical metal holding member 28 is detachably attached to the through-hole 21a. The holding member 28 is attached to the protruding portion so that the longitudinal direction of the holding member 28 is perpendicular to the flat surface of the protruding portion. The center of the wheel 5d of the spare tire 5 is detachably attached to the holding member 28.

[0035] As described above, the front wall portion 22 extends from the retaining portion 21 toward the front of the vehicle, and its front end is joined to the floor portion. As shown in Figures 3 and 4, a front welded portion 22c is provided at the front end.

[0036] The front wall portion 22 of this embodiment extends from the front of the retaining portion 21 toward the inclined portion 14 of the tire storage portion 12, and is inclined downward toward the front of the vehicle. The front wall portion 22 is formed with a longitudinal bead 22a that constitutes part of the above-mentioned radial beads 22a, 23a, 24a, and sub-beads 22b that are arranged on both sides of the longitudinal bead 22a in the vehicle width direction. The longitudinal bead 22a is a long bead that is formed over the entire longitudinal area of ​​the front wall portion 22 and extends from the front of the retaining portion 21 to the front end of the retaining bracket 20. The sub-beads 22b are shorter than the longitudinal bead 22a, and the front ends of the sub-beads 22b are arranged on both sides of the front end of the longitudinal bead 22a in the vehicle width direction.

[0037] The front welds 22c are provided at the front end of the longitudinal bead 22a and at the front ends of the sub-beads 22b on both sides. That is, in this example, three front welds 22c are arranged at intervals from one another in the vehicle width direction. The front welds 22c are spot welded to the inclined portion 14 of the bottom of the tire storage area 12. The three front welds 22c are also spot welded to the front ends of first bead portions 15 (described later) provided on the inclined portion 14 of the bottom.

[0038] Next, we will explain the outer wall portions 23, 24. As described above, the outer wall portions 23, 24 extend outward in both vehicle width directions from the retaining portion 21, and their side ends are joined to the floor portion, with outer welded portions 23c, 24c provided at the side ends.

[0039] The left outer wall portion 23 extends from the left side of the retaining portion 21 in the vehicle width direction toward the inclined portion 14 of the tire storage portion 12, and extends at an angle downward on the vehicle as it extends outward in the vehicle width direction. Similar to the front wall portion 22, the left outer wall portion 23 has a widthwise bead 23a formed thereon that constitutes part of the radial beads 22a, 23a, 24a described above. The widthwise bead 23a is an elongated bead formed over the entire longitudinal area of ​​the outer wall portion 23, and extends from the left side of the retaining portion 21 in the vehicle width direction to the left end of the retaining bracket 20.

[0040] The left outer welded portion 23c is provided at the left end of the widthwise bead 23a and on the front and rear sides of the widthwise bead 23a. The left outer welded portion 23c is spot welded to the left end of the inclined portion 14 at the bottom of the tire storage area 12.

[0041] The right outer wall 24 extends from the right side of the retaining portion 21 in the vehicle width direction toward the inclined portion 14 of the tire storage portion 12, and extends at an angle downward toward the vehicle width direction as it extends outward in the vehicle width direction. Similar to the left outer wall 23, the right outer wall 24 has a widthwise bead 24a formed thereon. The left and right outer walls 23, 24 may be configured symmetrically. Similar to the left outer weld 23c, the right outer weld 24c is provided at the right end of the widthwise bead 24a and on the front and rear sides of the widthwise bead 24a, and is spot-welded to the right end of the inclined portion 14 at the bottom of the tire storage portion 12. Note that the left and right outer walls 23, 24 are not limited to being symmetrical, and various modifications are possible to accommodate the shape of the rear floor panel 10, etc.

[0042] In this embodiment, the distance from the retaining portion 21 to the outer welded portions 23c and 24c is set longer than the distance from the retaining portion 21 to the front welded portion 22c.

[0043] As described above, the reinforcing walls 25, 26 are walls that connect the front wall 22 to the outer wall portions 23, 24 on both sides. In this example, the reinforcing walls 25, 26 include a left reinforcing wall 25 that connects the front wall 22 to the left outer wall portion 23, and a right reinforcing wall 26 that connects the front wall 22 to the right outer wall portion 24.

[0044] The front end of the left reinforcing wall portion 25 curves toward the rear of the vehicle as it moves toward the left outer side in the vehicle width direction. A weld portion 25a that is welded to the first bead portion 15 may be provided at the front end of the left reinforcing wall portion 25. Similarly, the front end of the right reinforcing wall portion 26 curves toward the rear of the vehicle as it moves toward the right outer side in the vehicle width direction. In addition, a weld portion 26a that is welded to the first bead portion 15 may also be provided at the front end of the right reinforcing wall portion 26.

[0045] As shown in Fig. 2, the battery pack 1 of this embodiment is disposed on the underside of the floor portion. Although detailed illustration of the battery pack 1 is omitted, it is a substantially rectangular parallelepiped device that has a predetermined dimension in the vehicle width direction and extends in the vehicle front-rear direction. The rear end of the battery pack 1 is disposed below a cross member 4 that is joined to the front portion of a rear floor panel 10, and slightly forward of the cross member 4. Note that the battery pack 1 is shown imaginarily in Fig. 2.

[0046] When the spare tire 5 is stored in the tire storage section 12, the holding member 28 is inserted into the center of the wheel 5d of the spare tire 5. In addition, in the stored spare tire 5, the lower end of the tread portion 5a located at the front is positioned slightly above the front outer peripheral surface portion 11a, and the lower end of the tread portion 5a located at the rear is positioned above the flat portion 17 at the bottom of the tire storage section 12 with a gap therebetween.

[0047] The spare tire 5 has corners (shoulders 5c) connecting the tread 5a and the side surfaces (sidewalls 5b). The shoulders 5c, which are located at the rear of the spare tire 5, are placed on the rear end of the inclined portions 14 of the tire storage compartment 12. This allows the spare tire 5 to be stored in the tire storage compartment 12 while maintaining an inclined posture.

[0048] As described above, by forming the retaining bracket 20 into a substantially semi-conical shape and providing the front wall portion 22 and the outer wall portion 24, it is possible to ensure the strength of the retaining bracket 20 and to stably hold the spare tire 5 in an inclined position. Furthermore, since the retaining bracket 20 is joined to the floor portion, more specifically, the retaining bracket 20 is spot-welded to the inclined portion 14 of the bottom portion that constitutes the tire storage portion 12, the rigidity of the bottom of the tire storage portion 12 is improved and deformation of the floor portion can be suppressed.

[0049] As a result, the rigidity of the vehicle body is improved and it is possible to suppress vibrations that cause abnormal noise. In addition, by forming the retaining bracket 20 into a roughly semi-conical shape with the rear portion cut off, the work of storing and removing the spare tire 5 is made easier.

[0050] According to this embodiment, in the rear structure of an electric vehicle, it is possible to improve the rigidity of the floor portion on which the spare tire 5 is placed and to improve the mounting rigidity of the spare tire 5. Furthermore, by improving the rigidity of the floor portion, when an impact load such as a rear-end collision is received, the battery pack 1 disposed in front of the spare tire 5 stored in the tire storage section 12 can be effectively protected from the impact load.

[0051] 4 and 6, the retaining bracket 20 of this embodiment may have a rear wall 30 that extends downward from the rear of the retaining portion 21 and is joined to the floor portion. For example, the rear wall 30 may have a vertical wall 31 that extends downward from the rear of the retaining portion 21 and a joint surface 35 that extends rearward from the lower end of the vertical wall 31. The joint surface 35 may extend along the inclination direction of the inclined portion 14 at the bottom of the tire storage portion 12 and be spot-welded to the inclined portion 14. This further improves the rigidity of the retaining bracket 20, and the provision of the joint surface 35 may also improve the rigidity of the bottom of the tire storage portion 12.

[0052] In this embodiment, as described above, the retaining bracket 20 is joined to the bottom of the tire storage section 12. As shown in Fig. 5, a first bead portion 15 extending in the vehicle width direction and curved so that a middle portion in the vehicle width direction is convex toward the rear of the vehicle is provided in the front portion of the bottom of the tire storage section 12, and a second bead portion extending in the vehicle width direction is provided in the bottom portion located rearward of the first bead portion 15. Furthermore, a front side wall portion 22 is joined to the first bead portion 15, and an outer wall portion 24 is joined to the second bead portion 16.

[0053] In this embodiment, the first bead portion 15 is located in the vehicle front-rear direction intermediate portion of the inclined portion 14 at the bottom, and is positioned forward of the center of the inclined portion 14 in the vehicle front-rear direction. Furthermore, the vehicle width direction intermediate portion of the first bead portion 15 extends substantially linearly in the vehicle width direction. The vehicle width direction outer portion of the first bead portion 15 curves forward as it moves outward in the vehicle width direction. The left outer portion of the first bead portion 15 is connected to the lower portion of the left curved portion 18a of the left side wall portion 18, and the right outer portion of the first bead portion 15 is connected to the lower portion of the right curved portion 19a of the right side wall portion 19.

[0054] The second bead portion 16 is located at the intermediate portion of the inclined portion 14 at the bottom in the vehicle longitudinal direction, approximately in the center of the inclined portion 14 in the vehicle longitudinal direction. The second bead portion 16 extends linearly in the vehicle width direction. The left side of the second bead portion 16 is connected to the outermost lower portion of the left curved portion 18a, and the right side is connected to the outermost lower portion of the right curved portion 19a. Here, "outermost" refers to the curved portions 18a, 19a located at the outermost positions in the vehicle width direction.

[0055] The bead portions 15, 16 formed at the bottom of the tire storage portion 12 improve the rigidity and strength of the tire storage portion 12, which is a recessed portion of the rear floor panel 10. This allows the load due to the weight of the spare tire 5 to be stably supported. Also, deformation of the floor portion can be effectively suppressed when an impact load is received due to a rear-end collision, etc. Furthermore, because the front wall portion 22 and the outer wall portion 24 of the retaining bracket 20 are joined to the first bead portion 15 and the second bead portion 16, the retaining rigidity of the spare tire 5 can be improved.

[0056] 5, the first bead portion 15 includes a front wall 15b that protrudes upward from the bottom of the tire storage compartment 12, a rear wall 15c that protrudes upward from the bottom and is spaced apart from the front wall 15b, and an upper surface 15a that connects the upper end of the front wall 15b to the upper end of the rear wall 15c. The upper surface 15a and the front wall 15b or the rear wall 15c form a ridge line 15d. Furthermore, the first bead portion 15 has a convex shape in which a middle portion in the vehicle width direction protrudes toward the rear of the vehicle. That is, the middle portion in the vehicle width direction of the front wall 15b is recessed rearward compared to the outer portions, and the middle portion in the vehicle width direction of the rear wall 15c protrudes rearward compared to the outer portions.

[0057] Furthermore, the front wall portion 22 of the holding bracket 20 is preferably joined to the upper surface portion 15a adjacent to the ridge line 15d corresponding to the convex shape. In this embodiment, as shown in Figures 3, 4, and 6, front welds 22c of the front wall portion 22 are spot-welded to the upper surface portion 15a adjacent to the ridge line 15d formed by the front wall 15b and the upper surface portion 15a. In other words, three front welds 22c are spot-welded to the upper surface portion 15a along the ridge line 15d.

[0058] By joining the retaining bracket 20 along the ridge line 15d of the first bead portion 15, it is possible to improve the retention rigidity of the spare tire 5. Furthermore, by spot welding the front welded portion 22c of the front wall portion 22 of the retaining bracket 20 along the convex shape, it is possible to improve the rigidity of the floor portion against loads acting in the longitudinal direction of the vehicle. In particular, in the event of an impact load from the rear of the vehicle due to a rear collision or the like, the load transmitted via the front welded portion 22c can be received by the forwardly curved portion of the outer side portion of the first bead portion 15 in the vehicle width direction, making it possible to effectively distribute the load to other members.

[0059] 5, 7, and 8, the second bead portion 16 has a concave cross-sectional shape that is recessed from the bottom toward the bottom of the vehicle, and the length in the front-to-rear direction of the outer wall portion 24 of the retaining bracket 20 is set to be longer than the length in the front-to-rear direction of the second bead portion 16. The outer wall portion 24 is preferably joined to the front and rear portions of the second bead in a state where it covers the second bead from above.

[0060] In this embodiment, the concave bottom surface 16a of the second bead portion 16 is formed to be substantially flat. A front surface 16b is formed in front of the bottom surface 16a, and the upper end of the front surface 16b is connected to the main surface of the inclined portion 14 at the bottom of the tire storage portion 12. Similarly, a rear surface 16c is formed in the rear of the bottom surface 16a, and the upper end of the rear surface 16c is connected to the main surface of the inclined portion 14 at the bottom of the tire storage portion 12. The front surface 16b slopes upward toward the front of the vehicle. The rear surface 16c slopes upward toward the rear of the vehicle. Here, the main surface refers to the portion of the inclined portion 14 where the first bead portion 15 and the second bead portion 16 are not formed.

[0061] 8, as described above, the outer welds 23c, 24c are arranged side by side in the vehicle front-rear direction at the outer ends of the outer wall portions 23, 24 of the retaining bracket 20. Of the outer welds 23c on the left outer wall portion 23, the foremost outer weld 23c is spot welded to the main surface of the inclined portion 14 located forward of the front surface 16b of the second bead portion 16. The last outer weld 23c is spot welded to the main surface of the inclined portion 14 located rearward of the rear surface 16c of the second bead portion 16.

[0062] The middle outer weld portion 23c is spot welded to the outer side in the vehicle width direction of the bottom surface 16a of the second bead portion 16. That is, the outer weld portion 23c provided on the widthwise bead 23a is spot welded to the bottom surface 16a of the second bead portion 16. The outer weld portion 23c of the outer wall portion 23 is joined to the second bead portion 16, the front side of the second bead portion 16, and the rear side of the second bead portion 16, while covering the second bead from above and straddling the second bead portion 16 in the front-to-rear direction. The outer weld portion 24c of the right outer wall portion 24 is arranged in a similar manner.

[0063] By welding the retaining bracket 20 so that it overlaps the second bead portion 16, it is possible to improve the retention rigidity of the spare tire 5. Furthermore, by forming widthwise beads 23a, 24a that make up the radial beads 22a, 23a, 24a so as to correspond to the longitudinal direction of the second bead portion 16 and joining these together, it is possible to improve the vehicle body rigidity in the vehicle width direction. For example, by forming a frame structure with the left and right widthwise beads 24a of the retaining bracket 20 and the second bead portion 16, it is possible to improve the rigidity of the rear floor panel 10 and suppress deformation of the floor portion due to loads acting in the vehicle width direction and loads acting in the roll direction.

[0064] In addition, in this embodiment, as shown in Figures 3, 4 and 9, the radial beads (front-rear beads 22a, widthwise beads 23a, 24a) have a concave cross-sectional shape, and the depth of the concave shape of the radial beads 22a, 23a, 24a is configured to become deeper as it approaches the bottom from the retaining portion 21.

[0065] For example, the depth of the concave shape of the widthwise beads 23a, 24a located on the outer side in the vehicle width direction is deeper than the depth of the widthwise beads 23a, 24a located on the inner side in the vehicle width direction. As described above, the outer welded portions 23c, 24c provided at the ends of the widthwise beads 23a, 24a are welded to the bottom surface 16a of the second bead portion 16, so the concave shape of the widthwise beads 23a, 24a located on the outer side in the vehicle width direction is deeper than the concave shape of the second bead portion 16.

[0066] In this way, by forming the radial beads 22a, 23a, 24a, it is possible to effectively improve the rigidity of the retaining bracket 20. For example, by making the recessed shapes deeper, the rigidity of the radial beads 23a, 24a in the longitudinal direction is improved, and the rigidity against loads acting in the vehicle longitudinal direction and vehicle width direction is improved.

[0067] Furthermore, it is preferable that a sub-bead 22b extending in the vehicle longitudinal direction is provided in a portion of the front wall portion 22 of the retaining bracket 20 that is joined to the first bead portion 15. In this embodiment, as shown in Figures 3, 4, and 9, front welded portions 22c where the front wall portion 22 is welded to the first bead portion 15 are provided in front of the longitudinal bead 22a and in front of the sub-beads 22b that are arranged on both sides of the front welded portion 22a. This improves the rigidity of the front welded portions 22c, and also improves the rigidity of retaining the spare tire 5.

[0068] In this embodiment, a reinforcing member 40 is joined to the underside of the second bead portion 16 where the outer welds 23c, 24c are spot welded. In this example, the outer welds 23c, 24c of the holding bracket 20 and the reinforcing member 40 are joined in a state where they sandwich the bottom surface 16a of the second bead portion 16 located at the bottom of the tire storage section 12. By providing the reinforcing member 40 in this manner, it is possible to further increase the holding rigidity of the holding bracket 20.

[0069] According to this embodiment, the rear of the vehicle is effectively reinforced, so that when an impact load is applied due to a rear-end collision or the like, deformation of the floor portion due to the inertia of the spare tire 5 can be effectively suppressed. As a result, the battery pack 1 located in front of the spare tire 5 can be effectively protected.

[0070] The description of the present embodiment is merely an example for explaining the present invention, and does not limit the invention described in the claims. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims.

[0071] For example, in this embodiment, the retaining bracket 20 is provided with the rear wall portion 30, but this is not limited to this. Depending on the size of the spare tire 5, the rear portion of the retaining bracket 20 may be open without providing the rear wall portion 30. Furthermore, the outer wall portions 23, 24 may be inclined slightly rearward as they extend outward in the vehicle width direction. [Explanation of symbols]

[0072] 1 Battery pack 2 Rear side members 2a Main body 2b Lid 2c flange 3 Back Panel 4 cross members 5 spare tires 5a Tread area 5b Sidewall 5c Shoulder 5d wheels 10 Rear floor panel 11 Outer peripheral surface 11a Front outer peripheral surface 11b Left outer peripheral surface 11c Right outer peripheral surface 12 Tire storage area 14 Slope 15 First bead section 15a Top part 15b Front wall 15c back wall 15d Ridgeline 16 Second bead section 16a Bottom 16b Front 16c rear 17 Plane part 17a flange 18 Left side wall 18a Left curved section 18b Left vertical wall section 18c flange 19 Right side wall 19a Right curved section 19b Right vertical wall section 19c flange 20 Retaining bracket 21 Holding part 21a Through hole 22 Front wall 22a Front-to-rear bead (radial bead) 22b Subbead 22c Front weld 23 Left outer wall 23a Width direction bead (radial bead) 23c Outside weld 24 Right outer wall 24a Width direction bead (radial bead) 24c Outside weld 25 Left side reinforced wall 25a Welded section 26 Right side reinforcement wall 26a Welded section 28 Retaining member 30 Rear side wall 31 Vertical Wall 35 Joint surface part 40 Reinforcement member

Claims

1. a battery pack disposed below a floor portion of the vehicle; a retaining bracket provided on the floor portion located on the vehicle rear side of the battery pack and holding a spare tire; and a rear structure for an electric vehicle, wherein the spare tire is held by the holding bracket in a state inclined downward toward the rear of the vehicle, and an upper end of a front portion of an outer circumferential surface of the spare tire is disposed higher than an upper end of a rear portion of the battery pack in the vehicle up-down direction, The retaining bracket is a holding portion disposed above the floor portion with a gap therebetween and configured to hold a radially central portion of the spare tire; a front wall portion extending from the holding portion toward the front side of the vehicle and having a front end joined to the floor portion; an outer wall portion extending from the holding portion to both outer sides in the vehicle width direction and having side ends joined to the floor portion; a reinforcing wall portion connecting the front wall portion and the outer wall portions on both sides; A rear structure of an electric vehicle, comprising:

2. 2. The rear structure of an electric vehicle according to claim 1, wherein the retaining bracket has a rear side wall portion that extends downward from the rear of the retaining portion and is joined to the floor portion.

3. The floor portion is provided with a tire storage portion recessed downward and capable of storing the spare tire, The retaining bracket is joined to the bottom of the tire storage compartment, a first bead portion extending in the vehicle width direction and curved so that a middle portion in the vehicle width direction is convex toward the rear of the vehicle is provided at a front portion of the bottom portion, and a second bead portion extending in the vehicle width direction is provided at the bottom portion located rearward of the first bead portion, 3. The rear structure of an electric vehicle according to claim 1, wherein the front wall portion is joined to the first bead portion, and the outer wall portion is joined to the second bead portion.

4. the first bead portion has a front vertical wall that protrudes upward from the bottom portion of the vehicle, a rear wall that is disposed rearward of the front wall portion with a gap therebetween and protrudes upward from the bottom portion, and an upper surface that connects an upper end of the front wall portion and an upper end of the rear wall portion, a vehicle width direction intermediate portion of each of the front vertical wall and the rear vertical wall has a curved portion that is curved so as to be convex toward the rear of the vehicle, The rear structure of an electric vehicle according to claim 3, wherein the front wall portion is joined adjacent to the curved portion.

5. the second bead portion has a concave cross-sectional shape that is concave from the bottom portion toward a vehicle lower side, a longitudinal length of the outer wall portion is set to be longer than a longitudinal length of the second bead portion, 4. The rear structure of an electric vehicle according to claim 3, wherein the outer wall portion is joined to the front and rear portions of the second bead portion in a state where the outer wall portion covers the second bead portion from above.

6. The retaining bracket has radial beads formed thereon, the radial beads extending from the retaining portion toward the front wall portion and the outer wall portions on both sides, 2. The rear structure of an electric vehicle according to claim 1, wherein the radial bead portion has a concave cross-sectional shape, and the depth of the concave shape of the radial bead portion is configured to become deeper as it approaches a bottom portion from the retaining portion.

7. 2. The rear structure of an electric vehicle according to claim 1, wherein a sub-bead extending in the longitudinal direction of the vehicle is provided in a portion of the front wall portion that is joined to the first bead portion.

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