Vehicle structure

Abstract

The present invention comprises a pair of side sills (15) that extend in the vehicle front-rear direction, a backbone (13) that extends in the vehicle front-rear direction at a center part in the vehicle width direction, and a cross member (17) that extends in the vehicle width direction and connects the pair of side sills (15). The cross member (17) is disposed so as to cover an upper surface (13a) of the backbone (13), has a lower part that is joined to at least a portion of the backbone (13), and has an upper part that is curved so as to have a height increasing toward the center side from both sides to the center side in the vehicle width direction.

Description

Vehicle Structure

[0001] The present invention relates to a vehicle structure.

[0002] In Patent Document 1, there is provided a vehicle structure including a floor panel forming a floor surface of a passenger compartment, a pair of left and right side sills respectively connected to both end portions in the vehicle width direction of the floor panel and extending in the vehicle longitudinal direction, and a cross member disposed between the pair of left and right side sills so as to extend in the vehicle width direction on the upper surface side of the floor panel. On side surfaces of the cross member in the front and rear of the vehicle, there are disclosed a vehicle structure in which a front portion and a rear portion of a backbone extending in the vehicle longitudinal direction at the center in the vehicle width direction are connected.

[0003] Japanese Patent No. 6889419

[0004] By the way, in the structure described in Patent Document 1, the backbone is divided into a front portion of the vehicle connected to a side surface on the front side of the vehicle of the cross member and a rear portion of the vehicle connected to a side surface on the rear side of the vehicle of the cross member. When the backbone is divided in the front and rear of the vehicle in this way, it may cause a decrease in the rigidity of the entire vehicle body, and there is a risk that the side sill and the floor panel may be locally deformed greatly during a side impact. For this reason, it is necessary to increase the number of cross members to enhance the rigidity of the vehicle body, which may lead to an increase in the weight and cost of the vehicle.

[0005] Therefore, an object of the present invention is to provide a vehicle structure that can enhance the rigidity of the vehicle body while suppressing an increase in the weight and cost of the vehicle, and particularly ensure high safety against side impacts.

[0006] The present invention has the following configuration. A pair of skeleton members extending in the vehicle longitudinal direction, a backbone extending in the vehicle longitudinal direction at the center in the vehicle width direction, and a cross member extending in the vehicle width direction and connecting the pair of skeleton members. The cross member is disposed so as to cover the upper surface of the backbone, the lower portion is joined to at least a part of the backbone, and the upper portion is curved so that the height increases from both sides in the vehicle width direction toward the center side. Vehicle structure.

[0007] According to the present invention, it is possible to provide a vehicle structure that can increase the rigidity of the vehicle body while suppressing increases in vehicle weight and cost, and that can ensure high safety, especially against side impacts.

[0008] Figure 1 is a perspective view from above of the floor panel illustrating the vehicle structure according to this embodiment. Figure 2 is a top view of the floor panel. Figure 3 is an exploded perspective view of the floor panel and cross member. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 1. Figure 5 is a diagram showing the cross member, where (a) is a perspective view, (b) is a side view, and (c) is a top view. Figure 6 is a diagram illustrating the structure of the cross member, where (a) is a perspective view, (b) is a side view, and (c) is a top view. Figure 7 is a diagram showing the reinforcement, where (a) is a perspective view, (b) is a side view, and (c) is a top view. Figure 8 is a perspective view of the arrangement of the side transmission members of the cross member. Figure 9 is a perspective view of the side transmission member from the side where it is joined to the side sill. Figure 10 is a perspective view of the side transmission member from below. Figure 11 is a perspective view of the cover constituting the side transmission member. Figure 12 is a perspective view of the bracket and reinforcing member constituting the side transmission member. Figure 13 is a perspective view of the placement of the central transmission member of the cross member. Figure 14 is a perspective view of the central transmission member from the outside in the vehicle width direction. Figure 15 is a perspective view of the cover constituting the central transmission member. Figure 16 is a perspective view of the bracket and reinforcing member constituting the central transmission member. Figure 17 is a perspective view of the underbody reinforcement mounted on the lower part of the floor panel.

[0009] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following drawings, the symbol FR indicates the front of the vehicle, the symbol UP indicates the top of the vehicle, and the symbol LH indicates the left side in the vehicle width direction (left side in the direction of travel). The opposite direction of symbol FR is the rear of the vehicle, the opposite direction of symbol UP is the bottom of the vehicle, and the opposite direction of symbol LH is the right side in the vehicle width direction (right side in the direction of travel). Hereinafter, these directions may simply be referred to as front, rear, top, bottom, left side, and right side.

[0010] (Overall Structure) Figure 1 is a perspective view from above of the floor panel 11 illustrating the vehicle structure according to this embodiment. Figure 2 is a top view of the floor panel 11. Figure 3 is an exploded perspective view of the floor panel 11 and the cross member 17. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 1.

[0011] The vehicle structure according to this embodiment is mainly applied to vehicles 10 such as automobiles. The type of vehicle 10 to which the vehicle structure is applied is not limited and may be, for example, an internal combustion engine vehicle (ICEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0012] As shown in Figures 1 to 4, the vehicle 10 to which the vehicle structure according to this embodiment is applied mainly comprises a floor panel 11, a backbone 13, side sills (skeletal members) 15, and cross members 17. The floor panel 11 extends substantially horizontally (substantially vertical in the vehicle's vertical direction). The backbone 13 is provided on the floor panel 11 and extends in the vehicle's longitudinal direction at the center of the vehicle's width direction. A pair of side sills 15 are provided on the vehicle 10 and are arranged on both sides of the vehicle 10, extending in the vehicle's longitudinal direction. As shown in Figure 4, the side sills 15 are formed in a substantially rectangular shape in a cross-sectional view along the vehicle's width direction.

[0013] The floor panel 11 is a plate material that constitutes the lower part of the passenger compartment, and is formed, for example, by pressing a steel plate. The front end of the floor panel 11 is connected to the rear end of the dash panel (not shown) and extends substantially horizontally towards the rear of the vehicle. The backbone 13 is provided in the center of the floor panel 11 in the vehicle width direction and is formed in a tunnel shape that protrudes upward and extends in the vehicle longitudinal direction. In this example, the floor panel 11 is constructed by joining a pair of panels 12, 12 to both sides of the backbone 13 in the vehicle width direction. The floor panel 11 may also be formed by integrally molding the backbone 13 and the panels 12 by pressing a steel plate. As shown in Figure 4, in the vehicle 10, a space S is formed between a pair of side sills 15, 15 in the lower part of the floor panel 11, and onboard equipment such as batteries and motors can be installed in this space S.

[0014] The backbone 13 has a flat upper surface 13a and outer surfaces 13b, 13b connected to both sides of the upper surface 13a in the vehicle width direction. The outer surfaces 13b are inclined downwards and outwards in the vehicle width direction. As a result, the backbone 13 is formed in a substantially trapezoidal shape in a cross-sectional view along the vehicle width direction.

[0015] The side sills 15 (skeletal members) and the portion of the backbone 13 that intersects with the cross member 17 are provided with side transmission members (transmission members) 21 and central transmission members (transmission members) 23. These side transmission members 21 and central transmission members 23 are provided in pairs. The pair of side transmission members 21, 21 are provided at both ends of the cross member 17 and extend along the side sills 15 in the longitudinal direction of the vehicle. The pair of central transmission members 23, 23 are provided in the central part of the cross member 17 in the vehicle width direction and extend along the backbone 13 in the longitudinal direction of the vehicle.

[0016] The cross member 17 extends in the vehicle width direction and is arranged to cover the upper surface 13a of the backbone 13. The cross member 17 connects the pair of side sills 15, 15 on both sides of the vehicle 10 by joining a pair of side transmission members 21, 21, which are provided at both ends in the vehicle width direction, to a pair of side sills 15, 15. In addition, the cross member 17 has a pair of central transmission members 23, 23, which are provided in the center and are joined to the backbone 13. Furthermore, the cross member 17 is joined to the upper surface of the floor panel 11, and the pair of side transmission members 21, 21 at both ends and the pair of central transmission members 23, 23 in the center are joined to the upper surface of the floor panel 11. In this way, in the vehicle 10, the pair of side sills 15, 15 are connected to each other by the floor panel 11 to which the cross member 17, the pair of side transmission members 21, 21 and the pair of central transmission members 23, 23 are joined to the upper surface, thus increasing the overall rigidity including the floor panel 11.

[0017] In this vehicle 10, the load applied to one side sill 15 during a side collision can be transmitted and distributed from the cross member 17 to the backbone 13 and the other side sill 15. This suppresses large localized deformations caused by the load applied to the side sill 15. Therefore, the structure can be simplified by reducing the number of cross members 17 placed between the pair of side sills 15, 15, while increasing the rigidity of the vehicle 10 and ensuring high safety. Moreover, since large deformations of the floor panel 11 during a side collision can be suppressed, onboard equipment installed in the space S between the side sills 15 below the floor panel 11 can be protected.

[0018] (Cross Member) Figure 5 shows the cross member 17, where (a) is a perspective view, (b) is a side view, and (c) is a top view. Figure 6 is a diagram illustrating the structure of the cross member 17, where (a) is a perspective view, (b) is a side view, and (c) is a top view. Figure 7 shows the reinforcement 47, where (a) is a perspective view, (b) is a side view, and (c) is a top view.

[0019] As shown in Figures 5(a) to 5(c) and Figures 6(a) to 6(c), the cross member 17 has an elongated shape extending in the vehicle width direction and includes an upper plate 31, a front plate 33 extending downward from the front side of the upper plate 31, and a rear plate 35 extending downward from the rear side of the upper plate 31. The front plate 33 has a flange portion 33a that protrudes forward from its lower edge, and the rear plate 35 has a flange portion 35a that protrudes rearward from its lower edge. As a result, the cross member 17 has a hat-shaped cross section and high rigidity. The flange portions 33a and 35a of the front plate 33 and rear plate 35 of the cross member 17 are joined to the floor panel 11.

[0020] The upper plate 31 of the cross member 17 has a flat surface 31a in the center in the vehicle width direction, and curved surfaces 31b on both sides in the vehicle width direction that gradually increase in height towards the flat surface 31a. In other words, the upper part of the cross member 17 is curved so that the height increases towards the center from both sides in the vehicle width direction. In this way, since the central part of the upper surface of the cross member 17 is a flat surface 31a, the height of the cross member 17 can be kept low, and a wide interior space can be secured.

[0021] The cross member 17 has upper joining pieces 43 at both ends in the vehicle width direction, formed by extending the upper plate 31 outward in the vehicle width direction. The cross member 17 also has side joining pieces 45 at both ends in the vehicle width direction of the front plate 33 and the rear plate 35, extending in the vehicle longitudinal direction. These upper joining pieces 43 and side joining pieces 45 are joined to the side transmission member 21 (see Figure 8).

[0022] The cross member 17 has a concave joint portion 41 at its lower part in the center in the vehicle width direction. The joint portion 41 has a bottom surface 41a and an inner surface 41b. The inner surface 41b is inclined downwards and outwards in the vehicle width direction. As a result, the joint portion 41 has a concave shape that is roughly trapezoidal when viewed from the front-rear direction. The backbone 13 is fitted into the concave joint portion 41 provided at the lower part of the cross member 17, and the bottom surface 41a and inner surface 41b of the joint portion 41 are joined to the upper surface 13a and outer surface 13b of the backbone 13 (see Figure 13). A part of the bottom surface 41a and the inner surface 41b of the joint portion 41 are joined to the upper surface 13a and outer surface 13b of the backbone 13 via the central transmission member 23. With this vehicle structure, the cross member 17 is joined to the backbone 13 in this manner, allowing the axial load transmitted to the cross member 17 to be effectively transmitted to the backbone 13 from the upper surface 13a and outer surface 13b of the backbone 13.

[0023] A reinforcement 47 is provided on the inside of the cross member 17. This reinforcement 47 is joined to the cross member 17. As shown in Figures 7(a) to 7(c), the reinforcement 47 has an outer shape that follows the inner surface of the cross member 17 and is a long shape that extends in the vehicle width direction.

[0024] The reinforcement 47 has an upper surface portion 51, a front portion 53 extending downward from the front side of the upper surface portion 51, and a rear portion 55 extending downward from the rear side of the upper surface portion 51. The reinforcement 47 has a bead portion 53a projecting forward from the front of the vehicle on the front portion 53, and a bead portion 55a projecting backward from the vehicle on the rear portion 55. Multiple bead portions 53a and 55a are formed, and they are spaced apart in the longitudinal direction of the reinforcement 47. The reinforcement 47 has a pair of convex portions 51a, 51a projecting upward from the upper surface portion 51. The pair of convex portions 51a, 51a are formed along the edges of the upper surface portion 51 in the front-rear direction of the vehicle and extend in the width direction of the vehicle. Thus, the rigidity of the reinforcement 47 is increased by forming bead portions 53a and 55a on the front portion 53 and the rear portion 55, and further increased by forming a pair of protrusions 51a and 51a on the upper portion 51.

[0025] The reinforcement 47 is fitted inside the cross member 17 and joined to the cross member 17. Specifically, the reinforcement 47 has bead portions 53a and 55a joined to the inner surface (rear surface) of the front plate 33 on the vehicle front side and the inner surface (entire surface) of the rear plate 35 on the vehicle rear side, respectively. Furthermore, the reinforcement 47 has a pair of protrusions 51a, 51a joined to the inner surface (lower surface) of the upper plate 31 on the cross member 17. As a result, the cross member 17 is made more rigid in the axial direction by the reinforcement 47.

[0026] (Side transmission members) Figure 8 is a perspective view of the arrangement of the side transmission members 21 on the cross member 17. Figure 9 is a perspective view of the side transmission member 21 as seen from the side where it is joined to the side sill 15. Figure 10 is a perspective view of the side transmission member 21 as seen from below. Figure 11 is a perspective view of the cover 121 that constitutes the side transmission member 21. Figure 12 is a perspective view of the brackets 123A, 123B and reinforcing members 125A, 125B, 125C that constitute the side transmission member 21.

[0027] As shown in Figures 8 to 10, the side transmission members 21 are joined to both ends of the cross member 17 in the vehicle width direction. The cross member 17 has its upper joining piece 43 and side joining piece 45 joined to the upper surface 21a and inner surface 21b of the side transmission member 21.

[0028] The side transmission members 21 provided at both ends of the cross member 17 in the vehicle width direction extend in the vehicle longitudinal direction along the inner surface 15a of the side sill 15 in the vehicle width direction. The side transmission member 21 has a forward projection (projection) 111 that protrudes toward the front of the vehicle relative to the front surface 17a, which is the outer surface of the front plate 33 on the vehicle front side of the cross member 17. Furthermore, the side transmission member 21 has a rear projection (projection) 113 that protrudes toward the rear of the vehicle relative to the rear surface 17b, which is the outer surface of the rear plate 35 on the vehicle rear side of the cross member 17.

[0029] This allows the load applied to the side sill 15 during a side collision to be transmitted to the cross member 17 from a wide area via the side transmission member 21, which has forward projections 111 and rear projections 113 that project in the longitudinal direction of the vehicle relative to the front surface 17a and rear surface 17b of the cross member 17. For example, even if a load is applied to the side sill 15 during a side collision in front of the front surface 17a of the cross member 17 or behind the rear surface 17b of the cross member 17, the load can be transmitted to the cross member 17 via the forward projections 111 and rear projections 113 of the side transmission member 21. Therefore, large local deformations caused by the load applied to the side sill 15 can be suppressed. This simplifies the structure by reducing the number of cross members 17 placed between the side sills 15, while increasing the rigidity of the vehicle 10 and ensuring high safety. Moreover, it protects on-board equipment such as batteries housed in the space S between the side sills 15 at the lower part of the backbone 13 from side collisions.

[0030] The side transmission member 21 has an upper connecting piece 115 on its outer side in the vehicle width direction, and this upper connecting piece 115 is joined to the upper surface 15b of the side sill 15 (see Figure 4). In this way, because the side transmission member 21 is joined to the upper surface 15b of the side sill 15 by the upper connecting piece 115, the load applied to the side sill 15 can be smoothly transmitted to the cross member 17 via the side transmission member 21. Furthermore, the cross member 17, which has the side transmission member 21 joined to the side sill 15 by the upper connecting piece 115, has both ends in the vehicle width direction at approximately the same height as the upper surface 15b of the side sill 15. This allows the load applied to the side sill 15 to be transmitted to the cross member 17 more smoothly via the side transmission member 21.

[0031] Furthermore, the side transmission member 21 has receiving surfaces 117 at both ends, and these receiving surfaces 117 are positioned opposite the inner surface 15a of the side sill 15. In this way, the side transmission member 21 is joined to the upper surface 15b of the side sill 15, and furthermore, by having receiving surfaces 117 that face the inner surface 15a of the side sill 15, the load applied to the side sill 15 can be transmitted more smoothly to the cross member 17 via the side transmission member 21.

[0032] Thus, the side transmission member 21, which abuts against the upper surface 15b and inner surface 15a of the side sill 15 and is joined to the side sill 15, is box-shaped when joined to the side sill 15. In other words, by abutting the side transmission member 21 against the upper surface 15b and inner surface 15a of the side sill 15 and forming a box shape, the rigidity of the joint between the side transmission member 21 and the side sill 15 can be increased. Furthermore, the side transmission member 21, which abuts against the upper surface 15b and inner surface 15a of the side sill 15 and forms a box shape, can more efficiently absorb the load applied to the side sill 15 during a side impact.

[0033] Furthermore, the side transmission member 21 is provided with a stepped portion 119 on the outer side in the vehicle width direction (see Figure 4). In other words, the cross member 17 has stepped portions 119 formed on the side transmission member 21 at both ends in the vehicle width direction where it connects to the side sill 15. By providing such stepped portions 119, when the side sill 15 is pushed by the impact of a side collision, the side transmission member 21 of the cross member 17 can be deformed starting from the stepped portion 119 to absorb the load.

[0034] As shown in Figures 11 and 12, the side transmission member 21 has a cover 121 and two brackets 123A and 123B. The two brackets 123A and 123B are provided at both ends of the cover 121 in the front-rear direction, respectively. In addition, three reinforcing members 125A, 125B, and 125C are provided on the inside of the side transmission member 21. These three reinforcing members 125A, 125B, and 125C are arranged in order from the front side of the vehicle to the rear side of the vehicle. It is preferable that these three reinforcing members 125A, 125B, and 125C be made of high-tensile steel, which has higher strength than commonly used steel materials.

[0035] The cover 121 has a side plate 131 that is erected in the vertical direction and a top plate 133 that extends laterally from the upper edge of the side plate 131, and the top joining piece 115 and the stepped portion 119 are formed on the top plate 133. The cover 121 also has a flange portion 137 that protrudes laterally from the lower edge of the side plate 131, and this flange portion 137 is joined to the floor panel 11.

[0036] Bracket 123A has a side plate 141 that is joined to the side plate 131 of cover 121 from the inner side, and a top plate 143 that is joined to the top plate 133 of cover 121 from the inner side. Bracket 123A has an end plate 145 on the side opposite to cover 121, and the receiving surface 117 is formed on the end plate 145. Bracket 123A also has a flange portion 147 that protrudes laterally from the lower edges of the side plate 141 and the end plate 145, and this flange portion 147 is joined to the floor panel 11.

[0037] Similarly, bracket 123B, which is on the opposite side in the front-rear direction from bracket 123A, has a side plate 151 that is joined to the side plate 131 of cover 121 from the inner side, and a top plate 153 that is joined to the top plate 133 of cover 121 from the inner side. Bracket 123B has an end plate 155 on the side opposite to cover 121, and the receiving surface 117 is formed on the end plate 155. Bracket 123B also has a flange portion 157 that protrudes laterally from the lower edges of the side plate 151 and the end plate 155, and this flange portion 157 is joined to the floor panel 11.

[0038] The reinforcing member 125A has an end plate 161, a pair of side plates 163, 163, and a pair of flange portions 165, 165. The end plate 161 is positioned on the outside in the vehicle width direction, and the side plates 163 extend inward in the vehicle width direction from both ends of the end plate 161 in the front-rear direction. The flange portions 165 extend in the vehicle front-rear direction from the ends of the side plates 163 opposite to the end plate 161 (the inner ends in the vehicle width direction). As a result, the reinforcing member 125A has a hat shape and high rigidity. The reinforcing member 125A also has a bead portion 163a on the side plate 163 that is aligned with the vehicle width direction. By forming the bead portion 163a on the side plate 163 in this way, the rigidity of the reinforcing member 125A is increased. The reinforcing member 125A also has a connecting piece 167 extending in the vehicle front-rear direction on the upper edge of each side plate 163. The reinforcing member 125A has a flange portion 165 that is joined to the inner surface of the side plate 131 of the cover 121, and a joining piece 167 that is joined to the inner surface of the top plate 133 of the cover 121.

[0039] The reinforcing member 125B has an end plate 171, a pair of side plates 173, 173, and a pair of flange portions 175, 175. The end plate 171 is positioned on the outside in the vehicle width direction, and the side plates 173 extend inward in the vehicle width direction from both ends of the end plate 171 in the front-rear direction. The flange portions 175 extend in the vehicle front-rear direction from the ends of the side plates 173 opposite to the end plate 171 (the inner ends in the vehicle width direction). As a result, the reinforcing member 125B has a hat shape and high rigidity. The reinforcing member 125B also has a bead portion 173a on the side plate 173 that is aligned with the vehicle width direction. By forming the bead portion 173a on the side plate 173 in this way, the rigidity of the reinforcing member 125B is increased. The reinforcing member 125B also has a connecting piece 177 extending in the vehicle front-rear direction on the upper edge of each side plate 173. The reinforcing member 125B has a flange portion 175 that is joined to the inner surface of the side plate 131 of the cover 121, and a joining piece 177 that is joined to the inner surface of the top plate 133 of the cover 121.

[0040] The reinforcing member 125C has an end plate 181, a pair of side plates 183, 183, and a pair of flange portions 185, 185. The end plate 181 is positioned on the outside in the vehicle width direction, and the side plates 183 extend inward in the vehicle width direction from both ends of the end plate 181 in the front-rear direction. The flange portions 185 extend in the vehicle front-rear direction from the ends of the side plates 183 opposite to the end plate 181 (the inner ends in the vehicle width direction). As a result, the reinforcing member 125C has a hat shape and high rigidity. The reinforcing member 125C also has a bead portion 183a on the side plate 183 that runs along the vehicle width direction. By forming the bead portion 183a on the side plate 183 in this way, the rigidity of the reinforcing member 125C is increased. The reinforcing member 125C also has a connecting piece 187 that extends between the pair of side plates 183, 183. The reinforcing member 125C has a flange portion 185 that is joined to the inner surface of the side plate 131 of the cover 121 and the side plate 151 of the bracket 123B, and a joining piece 187 that is joined to the inner surface of the top plate 133 of the cover 121.

[0041] In this way, reinforcing members 125A, 125B, and 125C are provided inside the side transmission member 21 so as to project outward in the vehicle width direction. Thereby, the rigidity of the side transmission member 21 can be increased by the reinforcing members 125A, 125B, and 125C. Therefore, the load applied to the side sill 15 during a side impact can be more efficiently transmitted to the cross member 17 by the side transmission member 21. Moreover, since the joining pieces 167, 177, and 187 of the reinforcing members 125A, 125B, and 125C are joined to the inner surface of the upper face plate 133 of the cover 121 that constitutes the upper part of the side transmission member 21, the rigidity of the side transmission member 21 can be further increased by these reinforcing members 125A, 125B, and 125C.

[0042] Also, in the side transmission member 21, the reinforcing member 125A is arranged at a position shifted toward the front side of the vehicle with respect to the cross member 17, and the reinforcing member 125C is arranged at a position shifted toward the rear side of the vehicle. By arranging the reinforcing members 125A and 125C in this way, the rigidity on the front side and the rear side of the vehicle of the side transmission member 21 rather than the cross member 17 can be increased.

[0043] Furthermore, in the side transmission member 21, the reinforcing member 125B is arranged at an overlapping position in the vehicle longitudinal direction with respect to the cross member 17. By arranging the reinforcing member 125B in this way, the rigidity of the overlapping position in the vehicle longitudinal direction of the cross member 17 in the side transmission member 21 can be increased.

[0044] Also, the side transmission member 21 has a hole portion 21c at its upper part (see FIG. 8). These hole portions 21c are fastening holes for fixing a seat rail (not shown) that supports the seat of the vehicle 10 slidably in the vehicle longitudinal direction with bolts or the like. And by fastening and fixing the seat rail to the side transmission member 21 using this hole portion 21c, the seat can be stably supported by this seat rail.

[0045] (Central Transmission Member) Figure 13 is a perspective view of the location of the central transmission member 23 of the cross member 17. Figure 14 is a perspective view of the central transmission member 23 as seen from the outside in the vehicle width direction. Figure 15 is a perspective view of the cover 221 that constitutes the central transmission member 23. Figure 16 is a perspective view of the brackets 223A, 223B and reinforcing members 225A, 225B, 225C that constitute the central transmission member.

[0046] As shown in Figures 13 and 14, the central transmission member 23 is joined to the central part of the cross member 17. The central transmission member 23 is positioned at the corner between the bottom surface 41a and the inner surface 41b of the concave joint 41 provided at the lower center of the cross member 17 in the vehicle width direction. The bottom surface 41a and inner surface 41b of the joint 41 of the cross member 17 are joined to the upper surface 23a and outer surface 23b of the central transmission member 23.

[0047] The central transmission member 23, located in the center of the cross member 17 in the vehicle width direction, extends in the vehicle longitudinal direction along the outer surface 13b of the backbone 13 in the vehicle width direction. The central transmission member 23 has a forward projection (projection) 211 that protrudes toward the front of the vehicle relative to the front surface 17a, which is the outer surface of the front plate 33 on the vehicle front side of the cross member 17. Furthermore, the central transmission member 23 has a rear projection (projection) 213 that protrudes toward the rear of the vehicle relative to the rear surface 17b, which is the outer surface of the rear plate 35 on the vehicle rear side of the cross member 17.

[0048] As a result, the load transmitted to the cross member 17 during a side collision can be transmitted to the backbone 13 from a wide area via the central transmission member 23, which has forward projections 211 and rear projections 213 that protrude in the longitudinal direction of the vehicle relative to the front surface 17a and rear surface 17b of the cross member 17. Therefore, compared to a structure without the central transmission member 23, the application of localized load from the cross member 17 to the backbone 13 can be avoided. This simplifies the structure by reducing the number of cross members arranged in the vehicle width direction, while increasing the rigidity of the vehicle 10 and ensuring high safety. Moreover, in the event of a side collision, on-board equipment such as batteries located in the space S between the side sills 15 at the lower part of the backbone 13 can be protected.

[0049] The central transmission member 23 has an upper surface joint piece 215 on the inner side in the vehicle width direction, and this upper surface joint piece 215 is joined to the upper surface 13a of the backbone 13. Further, the central transmission member 23 has a side surface joint piece 217 on the inner side in the vehicle width direction, and this side surface joint piece 217 is joined to the outer side surface 13b of the backbone 13. Thus, since the central transmission member 23 is joined to the upper surface 13a and the outer side surface 13b of the backbone 13 by the upper surface joint piece 215 and the side surface joint piece 217, the load applied to the cross member 17 can be smoothly transmitted to the backbone 13 via the central transmission member 23.

[0050] Thus, the central transmission member 23 that abuts against and is joined to the upper surface 13a and the outer side surface 13b of the backbone 13 is formed in a box shape in the state of being joined to the backbone 13. That is, since the central transmission member 23 abuts against the upper surface 13a and the outer side surface 13b of the backbone 13 and is formed in a box shape, the rigidity of the joint portion of the central transmission member 23 to the backbone 13 can be increased. Also, the load applied to the cross member 17 during a side impact can be more efficiently absorbed by the central transmission member 23 that abuts against the upper surface 13a and the outer side surface 13b of the backbone 13 and is formed in a box shape.

[0051] As shown in FIGS. 15 and 16, the central transmission member 23 has a cover 221 and two brackets 223A, 223B. The two brackets 223A, 223B are respectively provided at both ends in the front-rear direction of the cover 221. Also, three reinforcing members 225A, 225B, 225C are provided inside the central transmission member 23. These three reinforcing members 225A, 225B, 225C are arranged in order from the vehicle front side toward the vehicle rear side. It is preferable that these three reinforcing members 225A, 225B, 225C are formed of high-tensile steel having a higher strength than the generally used steel materials.

[0052] The cover 221 has a side plate 231 that is erected in the vertical direction and a top plate 233 that extends laterally from the upper edge of the side plate 231, and the top joining piece 215 is formed on the top plate 233. The cover 221 also has a flange portion 237 that protrudes laterally from the lower edge of the side plate 231, and this flange portion 237 is joined to the floor panel 11.

[0053] Bracket 223A has a side plate 241 that is joined to the side plate 231 of cover 221 from the inner side, and a top plate 243 that is joined to the top plate 233 of cover 221 from the inner side. Bracket 223A has an end plate 245 on the side opposite to cover 221, and the side joining piece 217 is formed on the end plate 245. Bracket 223A also has a flange portion 247 that protrudes laterally from the lower edges of the side plate 241 and the end plate 245, and this flange portion 247 is joined to the floor panel 11.

[0054] Similarly, bracket 223B, which is on the opposite side of bracket 223A in the front-rear direction, has a side plate 251 that is joined to the side plate 231 of cover 221 from the inner side, and a top plate 253 that is joined to the top plate 233 of cover 221 from the inner side. Bracket 223B has an end plate 255 on the side opposite to cover 221, and the side joining piece 217 is formed on the end plate 255. Bracket 223B also has a flange portion 257 that protrudes laterally from the lower edge of the side plate 251 and the end plate 255, and this flange portion 257 is joined to the floor panel 11.

[0055] The reinforcing member 225A has an end plate 261, a pair of side plates 263, 263, and a pair of flange portions 265, 265. The end plate 261 is positioned on the inside in the vehicle width direction, and the side plates 263 extend outward in the vehicle width direction from both ends of the end plate 261 in the front-rear direction. The flange portions 265 extend in the vehicle front-rear direction from the ends of the side plates 263 opposite to the end plate 261 (the inner ends in the vehicle width direction). As a result, the reinforcing member 225A has a hat shape and high rigidity. The reinforcing member 225A also has a bead portion 263a on the side plate 263 that is aligned with the vehicle width direction. By forming the bead portion 263a on the side plate 263 in this way, the rigidity of the reinforcing member 225A is increased. The reinforcing member 225A also has a connecting piece 267 extending in the vehicle front-rear direction on the upper edge of each side plate 263. The reinforcing member 225A has a flange portion 265 that is joined to the inner surface of the side plate 231 of the cover 221, and a joining piece 267 that is joined to the inner surface of the top plate 233 of the cover 221.

[0056] The reinforcing member 225B has an end plate 271, a pair of side plates 273, 273, and a pair of flange portions 275, 275. The end plate 271 is positioned on the inside in the vehicle width direction, and the side plates 273 extend outwards in the vehicle width direction from both ends of the end plate 271 in the front-rear direction. The flange portions 275 extend in the vehicle front-rear direction from the ends of the side plates 273 opposite to the end plate 271 (the inner ends in the vehicle width direction). As a result, the reinforcing member 225B has a hat shape and high rigidity. The reinforcing member 225B also has a bead portion 273a on the side plate 273 that is aligned with the vehicle width direction. By forming the bead portion 273a on the side plate 273 in this way, the rigidity of the reinforcing member 225B is increased. The reinforcing member 225B also has a connecting piece 277 extending in the vehicle front-rear direction on the upper edge of each side plate 273. The reinforcing member 225B has a flange portion 275 that is joined to the inner surface of the side plate 231 of the cover 221, and a joining piece 277 that is joined to the inner surface of the top plate 233 of the cover 221.

[0057] The reinforcing member 225C has an end plate 281, a pair of side plates 283, 283, and a pair of flange portions 285, 285. The end plate 281 is positioned on the inside in the vehicle width direction, and the side plates 283 extend outwards in the vehicle width direction from both ends of the end plate 281 in the front-rear direction. The flange portions 285 extend in the vehicle front-rear direction from the ends of the side plates 283 opposite to the end plate 281 (the inner ends in the vehicle width direction). As a result, the reinforcing member 225C has a hat shape and high rigidity. The reinforcing member 225C also has a bead portion 283a on the side plate 283 that runs along the vehicle width direction. By forming the bead portion 283a on the side plate 283 in this way, the rigidity of the reinforcing member 225C is increased. The reinforcing member 225C has a flange portion 285 that is joined to the inner surface of the side plate 231 of the cover 221 and the side plate 251 of the bracket 223B.

[0058] Thus, the central transmission member 23 is provided with reinforcing members 225A, 225B, and 225C protruding outward in the vehicle width direction. This increases the rigidity of the central transmission member 23. Therefore, the load applied from the cross member 17 during a side collision can be transmitted more efficiently to the backbone 13 by the central transmission member 23. Moreover, since the connecting pieces 267 and 277 of the reinforcing members 225A and 225B are joined to the inner surface of the upper plate 233 of the cover 221 that constitutes the upper part of the central transmission member 23, the rigidity of the central transmission member 23 can be further increased by these reinforcing members 225A and 225B.

[0059] Furthermore, in the central transmission member 23, the reinforcing member 225A is positioned offset to the front of the vehicle relative to the cross member 17, and the reinforcing member 225C is positioned offset to the rear of the vehicle. By arranging the reinforcing members 225A and 225C in this way, the rigidity of the central transmission member 23 can be increased on the vehicle front and rear sides compared to the cross member 17.

[0060] Furthermore, in the central transmission member 23, a reinforcing member 225B is positioned at an overlapping location in the vehicle's longitudinal direction relative to the cross member 17. By positioning the reinforcing member 225B in this manner, the rigidity of the central transmission member 23 at the overlapping location of the cross member 17 in the vehicle's longitudinal direction can be increased.

[0061] Furthermore, the central transmission member 23 has holes 23c at its upper part (see Figure 13). These holes 23c are fastening holes for fixing seat rails (not shown), which support the seat of the vehicle 10 so that it can slide in the front-rear direction of the vehicle, with bolts or the like. By fastening and fixing the seat rails to the central transmission member 23 using these holes 23c, the seat can be stably supported on these seat rails.

[0062] Vehicle 10 is equipped with an underfloor reinforcement (reinforcement) 291 at the lower part of the backbone 13 in the center of the floor panel 11 in the width direction of the vehicle (see Figure 13). This underfloor reinforcement 291 is formed, for example, by pressing a steel plate and is positioned across the location where the pair of central transmission members 23, 23 are located.

[0063] Figure 17 is a perspective view of the underbody reinforcement 291, which is mounted on the lower part of the floor panel 11. As shown in Figure 17, the underbody reinforcement 291, like the backbone 13, is formed in a substantially trapezoidal shape in a cross-sectional view along the vehicle width direction, and is positioned to be fitted onto the backbone 13 from below. The underbody reinforcement 291 has a pair of joining flange portions 293, 293 on both sides in the vehicle width direction. The underbody reinforcement 291, the backbone 13, and the central transmission member 23 overlap each other in some parts, and these overlapping portions are joined to each other. Specifically, the joining flange portions 293 of the underbody reinforcement 291 overlap the outer edge portion of the backbone 13 in the vehicle width direction and the flange portions 237, 247 of the cover 221 and bracket 223 of the central transmission member 23, and these overlapping portions are joined by, for example, spot welding or the like.

[0064] In this way, the underfloor reinforcement 291 is provided so as to straddle the location of the central transmission member 23 in the backbone 13, and the underfloor reinforcement 291, the backbone 13, and the central transmission member 23 are joined together by overlapping them, thereby firmly reinforcing the location of the central transmission member 23 in the backbone 13 with the underfloor reinforcement 291.

[0065] Thus, the present invention is not limited to the embodiments described above. It is also intended and within the scope of protection to be provided for the combination of each configuration of the embodiments, as well as for modifications and applications by those skilled in the art based on the description in the specification and well-known technology.

[0066] As described above, the following matters are disclosed in this specification: (1) A vehicle structure comprising: a pair of skeletal members extending in the longitudinal direction of the vehicle; a backbone extending in the longitudinal direction of the vehicle at the center of the vehicle width direction; and a cross member extending in the vehicle width direction and connecting the pair of skeletal members, wherein the cross member is disposed to cover the upper surface of the backbone, its lower part is joined to at least a part of the backbone, and its upper part is curved so as to increase in height from both sides in the vehicle width direction towards the center. With this vehicle structure, the load applied to the skeletal members during a side collision can be transmitted and distributed from the cross member to both the backbone and the other skeletal member. This makes it possible to suppress large local deformations caused by the load applied to the skeletal members. Therefore, it is possible to simplify the structure by reducing the number of cross members to be placed between the skeletal members, while increasing the rigidity of the vehicle and ensuring high safety. Moreover, it is possible to protect on-board equipment such as batteries housed between the skeletal members from side collisions.

[0067] (2) The vehicle structure according to (1), wherein the lower part of the cross member is joined to the outer surface of the backbone. With this vehicle structure, by joining the lower part of the cross member to the outer surface of the backbone, the axial load transmitted to the cross member can be effectively transmitted from the outer surface of the backbone to the backbone.

[0068] (3) The vehicle structure according to (1) or (2), wherein the lower part of the cross member has a concave shape having a bottom surface and an inner surface that are joined to the upper surface and outer surface of the backbone. With this vehicle structure, by joining the concave portion of the lower part of the cross member having a bottom surface and an inner surface to the upper surface and outer surface of the backbone, the axial load transmitted to the cross member can be effectively transmitted from the upper surface and outer surface of the backbone to the backbone.

[0069] (4) The vehicle structure according to any one of (1) to (3), wherein the upper surface of the cross member has a flat central portion. With this vehicle structure, by making the central portion of the upper part of the cross member a flat surface, the height of the cross member can be reduced and a large interior space can be secured.

[0070] (5) The vehicle structure according to any one of (1) to (4), wherein the cross member has both ends in the vehicle width direction at approximately the same height as the upper surfaces of the pair of skeletal members. With this vehicle structure, when the skeletal members are pushed by the impact of a side collision, the load can be efficiently transmitted from the skeletal members to the cross member.

[0071] (6) The vehicle structure according to any one of (1) to (5), wherein the cross member has stepped portions at both ends. With this vehicle structure, when the frame member is pushed by the impact of a side collision, the load can be absorbed by deforming both ends of the cross member starting from the stepped portion.

[0072] (7) A vehicle structure according to any one of (1) to (6), wherein a reinforcement having an outer shape that conforms to the inner surface of the cross member is provided on the inside of the cross member, and the reinforcement is joined to the cross member. With this vehicle structure, the rigidity of the cross member can be increased in the axial direction by the reinforcement.

[0073] (8) The vehicle structure according to (7), wherein the reinforcement has bead portions projecting in the longitudinal direction of the vehicle from the front and rear front and rear sides of the vehicle, and the inner surfaces of the front and rear front plates of the cross member on the vehicle side and the bead portions are joined to each other. With this vehicle structure, the rigidity of the reinforcement can be increased by the bead portions, and moreover, the rigidity of the cross member can be increased by firmly joining the reinforcement to the cross member.

[0074] (9) The vehicle structure according to (7) or (8), wherein the reinforcement has protrusions extending in the vehicle width direction on both edges in the vehicle front-rear direction on its upper surface, and the inner surface of the upper plate of the cross member and the protrusions are joined together. With this vehicle structure, the rigidity of the reinforcement can be increased by the protrusions, and moreover, the rigidity of the cross member can be increased by firmly joining the reinforcement to the cross member.

[0075] (10) A vehicle structure according to any one of (1) to (9), comprising a floor panel having the backbone, wherein the cross member is joined to the upper surface of the floor panel. With this vehicle structure, the rigidity of the floor panel can be increased by joining the cross member to the upper surface of the floor panel.

[0076] (11) The vehicle structure according to (10), wherein the floor panel connects the pair of skeletal members. With this vehicle structure, the rigidity of the entire structure, including the floor panel, can be increased by connecting the skeletal members with a floor panel to which a cross member is joined on the upper surface.

[0077] 10 Vehicle 11 Floor panel 13 Backbone 13a Top surface 13b Outer surface 15 Side sill (frame member) 17 Cross member 31 Top plate 31a Flat surface 33 Front plate 35 Rear plate 41a Bottom surface 41b Inner surface 47 Reinforcement 51a Protrusion 55a Bead portion 119 Step portion

Claims

1. A vehicle structure comprising: a pair of skeletal members extending in the longitudinal direction of the vehicle; a backbone extending in the longitudinal direction of the vehicle at the center of the vehicle width direction; and a cross member extending in the vehicle width direction and connecting the pair of skeletal members, wherein the cross member is disposed to cover the upper surface of the backbone, its lower part is joined to at least a part of the backbone, and its upper part is curved so as to increase in height from both sides in the vehicle width direction towards the center.

2. The lower part of the cross member is joined to the outer surface of the backbone, the vehicle structure according to claim 1.

3. The lower part of the cross member has a concave shape having a bottom surface and an inner surface that are joined to the upper surface and outer surface of the backbone, as described in claim 1.

4. The vehicle structure according to claim 1, wherein the upper surface of the cross member has a flat central portion.

5. The vehicle structure according to claim 1, wherein both ends of the cross member in the vehicle width direction are at substantially the same height as the upper surfaces of the pair of skeletal members.

6. The vehicle structure according to claim 1, wherein the cross member has stepped portions at both ends.

7. The vehicle structure according to claim 1, wherein a reinforcement having an outer shape that conforms to the inner surface of the cross member is provided inside the cross member, and the reinforcement is joined to the cross member.

8. The vehicle structure according to claim 7, wherein the reinforcement has bead portions projecting in the longitudinal direction of the vehicle from the front and rear front and rear sides of the vehicle, and the inner surfaces of the front and rear front plates of the cross member are joined to the bead portions.

9. The vehicle structure according to claim 7, wherein the reinforcement has protrusions extending in the vehicle width direction on both edges of the upper surface in the vehicle front-rear direction, and the inner surface of the upper plate of the cross member and the protrusions are joined together.

10. The vehicle structure according to claim 1, comprising a floor panel having the backbone, wherein the cross member is joined to the upper surface of the floor panel.

11. The vehicle structure according to claim 10, wherein the floor panel connects the pair of skeletal members.

Images