JP6800088B2 - Body undercarriage - Google Patents

Description

The present invention relates to a vehicle body lower structure.

As a vehicle body lower structure, for example, a floor panel is erected between a left side sill and a right side sill, and a battery pack is mounted below the floor panel. A battery is housed inside the battery pack. A battery cross member is provided inside the battery pack.
The battery cross member is fastened to the lower part of the floor cross member with bolts and nuts. The floor cross member is attached to the floor panel. The rigidity of the vehicle body is increased by fastening the battery cross member to the floor cross member (see, for example, Patent Document 1).

U.S. Pat. No. 8,336,658

By the way, in the vehicle body lower structure, it is conceivable that a seat is attached to the floor cross member. The seat is provided with a tongue support portion (belt support portion). That is, the belt support portion is connected to the floor cross member via the seat. By supporting the tongue of the seat belt by this belt support portion, the occupant is restrained by the seat belt. In this state, for example, when an impact load is input from the front of the vehicle, a tensile load acts on the belt support portion via the seat belt.
Therefore, it is necessary to firmly support the belt support portion with the floor cross member. As a countermeasure, it is conceivable to increase the rigidity of the floor cross member. However, if an attempt is made to increase the rigidity of the floor cross member more than necessary, this hinders the weight of the floor cross member (that is, the weight of the vehicle body) from being suppressed, and there is room for improvement from this point of view.

Therefore, the present invention provides a vehicle body lower structure capable of supporting the belt support portion without increasing the rigidity of the floor cross member more than necessary.

In order to solve the above problems, in the invention described in claim 1, an underfloor mounting component (for example, the battery pack 28 of the embodiment) is attached below the floor panel (for example, the floor panel 16 of the embodiment). In the vehicle body lower structure (for example, the vehicle body lower structure 12 of the embodiment), a floor cross member provided on the floor panel and extending in the vehicle width direction (for example, the first floor cross member 34 and the second floor cross member 35 of the embodiment). ), An underfloor cross member (for example, the battery cross member 131 of the embodiment) arranged below the floor cross member and attached to the underfloor mounting component, and a fastening unit for attaching the underfloor cross member to the floor cross member. (For example, the outer fastening unit 21 (21A) and the inner fastening unit 21 (21B) of the embodiment) and the seats attached to the floor cross member (for example, the driver seat 31 and the passenger seat 32 of the embodiment). The seat is attached to the floor cross member in the vicinity of the fastening unit so that a load (for example, the tensile loads F2 and F5 of the embodiment) can be transmitted to the fastening unit (for example, the seat mounting portion). , And the belt support portion (for example, the tongue support portion 54 of the embodiment) which is connected to the seat attachment portion and supports the seat belt (for example, the seat belt 87 of the embodiment). The seat mounting portion includes a pair of seat support portions (for example, the first and second seat rails 56 and 57 of the embodiment) provided at intervals in the vehicle width direction, and the pair of seats. One of the support portions (for example, the second seat rail 57 of the embodiment) is attached to the vehicle width direction center side of the fastening unit on the vehicle width direction center side, and the other of the pair of seat support portions (for example, the embodiment). The first seat rail 56) of the embodiment is characterized in that it is attached to the end side in the vehicle width direction with respect to the fastening unit on the end side in the vehicle width direction .
The invention according to claim 2 is a vehicle body lower structure (for example, the embodiment) in which an underfloor mounting component (for example, the battery pack 28 of the embodiment) is attached below the floor panel (for example, the floor panel 16 of the embodiment). In the vehicle body lower structure 12), a floor cross member (for example, the first floor cross member 34 and the second floor cross member 35 of the embodiment) provided on the floor panel and extending in the vehicle width direction and a lower portion of the floor cross member. An underfloor cross member (for example, the battery cross member 131 of the embodiment) arranged in the floor cross member and attached to the underfloor mounting component, and a fastening unit (for example, an outer fastening unit of the embodiment) for attaching the underfloor cross member to the floor cross member. 21 (21A), internal fastening unit 21 (21B)) and a seat attached to the floor cross member (for example, the driver seat 31 of the embodiment, the passenger seat 32), and the seat is the floor. A seat attachment portion (for example, the seat attachment portion 53 of the embodiment) capable of transmitting a load (for example, the tensile load F2 and F5 of the embodiment) to the fastening unit by being attached to the vicinity of the fastening unit among the cross members. And a belt support portion (for example, the tongue support portion 54 of the embodiment) which is connected to the seat attachment portion and supports the seat belt (for example, the seat belt 87 of the embodiment). A fastening bracket provided on the floor cross member (for example, the outer fastening bracket 141 and the inner fastening bracket 142 of the embodiment) and a fastening member for fastening the underfloor cross member to the fastening bracket (for example, the outer fastening member 133 of the embodiment). , The inner fastening member 134), and the fastening bracket is arranged along the floor panel and stands from the bottom portion (for example, the bottom portions 185, 202 of the embodiment) and the bottom portion to be fastened to the fastening member. The raised legs (for example, the outer legs 186,203 and the inner legs 187,204 of the embodiment) and the upper end of the legs extend along the floor cross member, and among the floor cross members, the said The seat attachment portion is fixed in the vicinity of the fastening seat portion (for example, the first and second front fastening seat portions 23 and 24, and the first and second rear fastening seat portions 25 and 26 of the embodiment) to which the seat mounting portion is fastened. Thereby, the fastening seat portion has a flange capable of transmitting the load (for example, the outer upper flange 188,307 and the inner upper flange 206,308 of the embodiment). It is characterized by that.

By attaching the underfloor cross member to the floor cross member with the fastening unit in this way, the floor cross member is reinforced by the underfloor cross member. As a result, the rigidity of the vehicle body can be increased.
By the way, the belt support portion is connected to the seat mounting portion. Therefore, for example, when an impact load is input from the front of the vehicle, a tensile load acts on the belt support portion via the seat belt.

Therefore, the seat mounting portion is mounted near the fastening unit among the floor cross members. Therefore, the tensile load acting on the belt support portion can be transmitted to the fastening unit via the seat mounting portion, and the tensile load can be supported by the fastening unit. That is, the occupant can be suitably restrained by the seat belt.
In this way, the tensile load acting on the belt support portion can be supported by using the fastening unit. As a result, the belt support portion can be supported without increasing the rigidity of the floor cross member more than necessary.

In this way, the bottom of the fastening bracket is fastened to the fastening member. Further, the upper flange of the fastening bracket is fixed in the vicinity of the fastening seat portion of the floor cross member. Further, a seat mounting portion is fastened to the fastening seat portion.
Therefore, when an impact load is input from the front of the vehicle, the tensile load acting on the seat mounting portion can be transmitted from the fastening seat portion of the floor cross member to the underfloor cross member via the fastening bracket and the fastening member. As a result, the tensile load acting on the seat belt can be supported by two members, the floor cross member and the underfloor cross member.
In this way, by supporting the tensile load acting on the seat belt with the cross members of the two members, the belt support portion can be supported without increasing the rigidity of the floor cross member more than necessary.

According to the third aspect of the present invention, the floor cross member is an end member (for example, end member 171 and 301 of the embodiment) and a straight part member (for example, for example) which are joined in order from the outside to the center in the vehicle width direction. , A linear portion member 172, 302 of the embodiment), and a central portion member (for example, the central portion member 173, 303 of the embodiment), and a first joint portion (for example, the linear portion member) between the end portion member and the straight portion member. The first joint portion 184,197) of the embodiment and the second joint portion between the straight portion member and the central portion member (for example, the second joint portion 196, 198 of the embodiment) are located below the floor panel. It is characterized in that the arranged underfloor mounting parts are joined to the fastening bracket to be connected.

Here, the end members of the floor cross member are joined to the side sill. Further, the central member of the floor cross member is formed according to, for example, a floor tunnel. Therefore, the end member and the center member have a relatively complicated shape. On the other hand, the straight line member can be suppressed to a relatively simple shape.
The floor cross member is divided into three members: an end member, a straight member, and a central member. Therefore, for example, an end member or a center member having a complicated shape can be drawn (drawed), and a straight member having a simple shape can be bent (bent). By bending the straight portion member in this way, the manufacturing cost of the floor cross member can be reduced.

Further, it is possible to optimize the collision mode by making the strengths of the end member, the straight member, and the center member different. In this case, it is required to devise a method for ensuring the strength of the first joint portion between the end member and the straight portion member and the second joint portion between the straight portion member and the central portion member. Therefore, we decided to join the fastening bracket to the first joint and the second joint. The fastening bracket uses a high-strength member to support the underfloor mounting component (that is, the in-vehicle component).
As a result, by joining the fastening bracket to the first joint and the second joint, the first joint and the second joint can be reinforced by the fastening bracket, and the load transmission performance of the floor cross member can be ensured. ..

According to the fourth aspect of the present invention, the fastening seat portion of the floor cross member is formed on the central portion member, and the flange is sandwiched between the central portion member and the straight portion member. It is a feature.

In this way, the upper flange of the fastening bracket is sandwiched between the central member and the straight member. Therefore, the upper flange of the fastening bracket is firmly supported between the central member and the straight member.
Further, the fastening seat portion of the floor cross member is formed in the central portion member. A belt support portion is connected to the fastening seat portion via a seat mounting portion. Therefore, when a tensile load is applied to the belt support portion, the tensile load can be reliably transmitted from the upper flange to the underfloor cross member via the fastening bracket. As a result, the tensile load can be reliably supported by the two members, the floor cross member and the underfloor cross member, and the support strength of the belt support portion (that is, the seat belt) can be secured.

In the invention according to claim 5, the fastening seat portion is provided on the vehicle width direction center side and the vehicle width direction end portion side of the floor cross member, and the seat mounting portions are spaced apart in the vehicle width direction. A pair of seat support portions (for example, the first and second seat rails 56 and 57 of the embodiment) provided therein are provided, and one of the pair of seat support portions (for example, the second seat rail 57 of the embodiment) is provided. Is attached in the vicinity of the fastening member on the center side so as to reinforce the fastening member on the center side in the vehicle width direction, and the other of the pair of seat support portions (for example, the first seat rail 56 of the embodiment) is a vehicle. It is characterized in that it is attached in the vicinity of the fastening member on the end side so as to reinforce the fastening member on the end side in the width direction.

In this way, fastening seats are formed on the vehicle width direction center side and the vehicle width direction end side of the floor cross member. Further, one seat support portion is attached in the vicinity of the fastening seat portion on the center side so as to reinforce the fastening seat portion on the center side in the vehicle width direction. Further, the other seat support portion is attached in the vicinity of the fastening seat portion on the end side so as to reinforce the fastening seat portion on the end side in the vehicle width direction. The rigidity of the floor cross member is sufficiently secured by the pair of seat support portions.
Therefore, when a tensile load is applied to the belt support portion, the tensile load can be more reliably supported by the two members, the floor cross member and the underfloor cross member, and the support strength of the belt support portion (that is, the seat belt) is further increased. Can be secured well.

According to the sixth aspect of the present invention, the seat support portion is a seat rail extending in the front-rear direction of the vehicle body so that the seat can be slidably moved in the front-rear direction of the vehicle body, and the floor cross members are arranged in pairs at least in the front-rear direction of the vehicle body. The seat rails (for example, the first and second seat rails 56 and 57 of the embodiment) are attached to the fastening seat portions of the pair of floor cross members.

As described above, the seat support portion is a seat rail extending in the front-rear direction of the vehicle body. Further, seat rails are attached to fastening seats of a pair of floor cross members arranged in the front-rear direction of the vehicle body. Therefore, the rigidity of the floor cross member is sufficiently secured by the seat rail. As a result, when a tensile load is applied to the belt support portion, the tensile load can be more reliably supported by the two members, the floor cross member and the underfloor cross member. That is, the support strength of the belt support portion (that is, the seat belt) can be secured even better.
Further, by attaching the seat rail to the fastening seat portion of the pair of floor cross members, the fastening bracket in the vicinity of the fastening seat portion can be reinforced by the seat rail. Therefore, the rigidity of the fastening bracket is increased. As a result, the underfloor mounted parts can be reliably held, and the holding strength of the underfloor mounted parts can be secured even better.

According to the present invention, the seat mounting portion is mounted in the vicinity of the fastening unit so that the load can be transmitted to the fastening unit among the floor cross members. As a result, the belt support portion can be supported without increasing the rigidity of the floor cross member more than necessary.

It is a perspective view which shows the vehicle body lower structure in one Embodiment of this invention. It is a top view which shows the vehicle body lower structure in one Embodiment of this invention. It is a perspective view which shows the state which the car body lower structure in one Embodiment of this invention is broken along the line III-III of FIG. It is a perspective view which shows the state which the car body lower structure in one Embodiment of this invention is broken along the IV-IV line of FIG. It is sectional drawing which shows the state which the car body lower structure in one Embodiment of this invention is broken along the VV line of FIG. It is a perspective view which shows the 1st floor cross member and the 2nd floor cross member of the vehicle body lower structure in one Embodiment of this invention. It is an exploded perspective view which shows the 1st floor cross member and the 2nd floor cross member of the vehicle body lower structure in one Embodiment of this invention. It is a perspective view which shows the expansion of the IIX part of FIG. 7 in the vehicle body lower structure in one Embodiment of this invention. It is sectional drawing which shows the enlargement of the IX part of FIG. It is sectional drawing which shows the X part enlargement of FIG. 5 in the vehicle body lower structure in one Embodiment of this invention. It is a perspective view explaining an example which supports a tongue support part when an impact load is input from the front of a vehicle in the vehicle body lower structure in one Embodiment of this invention.

An embodiment of the present invention will be described with reference to the drawings. In the drawings, the arrow FR points to the front of the vehicle, the arrow UP points to the upper side of the vehicle, and the arrow LH points to the left side of the vehicle.
As shown in FIGS. 1 and 2, the vehicle body 10 includes a vehicle body lower structure 12 that constitutes a lower portion of the vehicle body 10. The vehicle body lower structure 12 includes a left side sill 14, a right side sill 15, a floor panel 16, a floor cross member unit 17, a fastening unit 21 (see FIG. 5), and a battery pack (underfloor mounting component) 28 (see FIG. 5). ), A driver seat 31, and a passenger seat 32.
Since the vehicle body lower structure 12 is composed of members that are substantially symmetrical, the description of each component on the left side will be described below, and the description of each component on the right side will be omitted.

The left side sill 14 is provided on the left side portion 10a of both side portions of the vehicle body 10 and extends in the front-rear direction of the vehicle body. The right side sill 15 is provided on the right side portion 10b of both side portions of the vehicle body 10 and extends in the front-rear direction of the vehicle body.
A floor panel 16 is arranged between the left side sill 14 and the right side sill 15. The floor panel 16 is erected on the left side sill 14 and the right side sill 15. A floor cross member unit 17 is attached to the upper surface 16a of the floor panel 16. The floor cross member unit 17 includes a first floor cross member 34, a second floor cross member 35, and a third floor cross member 36.

The first floor cross member 34 is arranged on the front side of the vehicle body in the vehicle interior 38. The first floor cross member 34 is erected on the left side sill 14 and the right side sill 15 so as to face the vehicle width direction.
The second floor cross member 35 is arranged on the rear side of the vehicle body of the first floor cross member 34. The second floor cross member 35 is erected on the left side sill 14 and the right side sill 15 so as to face the vehicle width direction, and extends in parallel with the first floor cross member 34.
The third floor cross member 36 is arranged on the rear side of the vehicle body of the second floor cross member 35. The third floor cross member 36 is erected on the left side sill 14 and the right side sill 15 so as to face the vehicle width direction, and extends in parallel with the second floor cross member 35.

The first floor cross member 34, the second floor cross member 35, and the third floor cross member 36 are provided at intervals in the front-rear direction of the vehicle body, respectively. For example, a driver seat 31 is attached to the right half of the first floor cross member 34 and the second floor cross member 35 with fastening members such as bolts 37 and nuts. For example, a passenger seat 32 is attached to the left half of the first floor cross member 34 and the second floor cross member 35 with fastening members such as bolts 41 and nuts 42 (see FIG. 5). Further, a rear seat 43 is provided on the third floor cross member 36.

In this way, the driver seat 31 is attached to the right half of the first floor cross member 34 and the second floor cross member 35. Further, a passenger seat 32 (see also FIG. 3) is attached to the left half of the first floor cross member 34 and the second floor cross member 35.
The driver seat 31 and the passenger seat 32 are symmetrical members. Hereinafter, the passenger seat 32 will be described in detail, and the description of the driver seat 31 will be omitted.

The first floor cross member 34 has a first front fastening seat portion (fastening seat portion) 23 and a second front fastening seat portion (fastening seat portion) 24 in the left half portion. The first front fastening seat portion 23 is formed at a portion of the first floor cross member 34 near the left end portion 34a. The second front fastening seat portion 24 is formed at a portion of the first floor cross member 34 near the center 34b.
The second floor cross member 35 has a first rear fastening seat portion (fastening seat portion) 25 and a second rear fastening seat portion (fastening seat portion) 26 in the left half portion. The first rear fastening seat portion 25 is formed at a portion closer to the left end portion 35a of the second floor cross member 35. The second rear fastening seat portion 26 is formed at a portion of the second floor cross member 35 near the center 35b.
The passenger seat 32 is attached to the first front fastening seat 23, the first rear fastening seat 25, the second front fastening seat 24, and the second rear fastening seat 26 with bolts 41 and nuts 42 (see FIG. 5). Has been done.

As shown in FIG. 3, the passenger seat 32 includes a seat cushion 51, a seat back 52, a seat mounting portion 53, and a tongue support portion (belt support portion) 54.
The seat cushion 51 is provided along the floor panel 16 so that the occupant can sit on it. The seat back 52 is raised from the rear portion of the seat back 52 so as to support the upper body of the occupant seated on the seat cushion 51.
The seat mounting portion 53 includes an outer seat rail 56 and an inner seat rail 57 as a pair of seat support portions. Hereinafter, the outer seat rail 56 will be referred to as a "first seat rail 56". The inner seat rail 57 is referred to as a "second seat rail 57".
The first seat rail 56 and the second seat rail 57 are arranged at intervals in the vehicle width direction.
The first seat rail 56 includes a first fixed rail 71, a first movable rail 72, and a first support bracket 73.

As shown in FIG. 4, the first fixed rail 71 is attached to the first front fastening seat portion 23 and the first rear fastening seat portion 25. By attaching the first fixed rail 71 to the first front fastening seat portion 23 and the first rear fastening seat portion 25, the first fixed rail 71 extends in the front-rear direction of the vehicle body. A first movable rail 72 (see FIG. 3) is connected to the first fixed rail 71 so as to be slidable in the front-rear direction of the vehicle body.
The first movable rail 72 is attached to the outer portion 51a of the seat cushion 51 via the first support bracket 73 (see FIG. 3).

As shown in FIGS. 2 and 3, the second seat rail 57 is configured to be substantially symmetrical with the first seat rail 56. That is, the second seat rail 57 includes a second fixed rail 75, a second movable rail 76, and a second support bracket 77.
The second fixed rail 75 is attached to the second front fastening seat portion 24 and the second rear fastening seat portion 26. By attaching the second fixed rail 75 to the second front fastening seat portion 24 and the second rear fastening seat portion 26, the second fixed rail 75 extends in the vehicle body front-rear direction in parallel with the first fixed rail 71. The second movable rail 76 is connected to the second fixed rail 75 so as to be slidable in the front-rear direction of the vehicle body.
The second movable rail 76 is attached to the inner portion 51b of the seat cushion 51 via the second support bracket 77.
As a result, the passenger seat 32 is supported by the seat mounting portion 53 so as to be slidable in the front-rear direction of the vehicle body.

As described above, the first seat rail 56 is a seat rail extending in the front-rear direction of the vehicle body. The second seat rail 57 is a seat rail extending in the front-rear direction of the vehicle body. The first seat rail 56 is attached to the first front fastening seat portion 23 of the first floor cross member 34 and the first rear fastening seat portion 25 of the second floor cross member 35. The second seat rail 57 is attached to the second front fastening seat portion 24 of the first floor cross member 34 and the second rear fastening seat portion 26 of the second floor cross member 35.
Therefore, the rigidity of the first floor cross member 34 and the second floor cross member 35 is sufficiently secured by the first seat rail 56 and the second seat rail 57.

The tongue support portion 54 is connected to the second support bracket 77. The tongue support portion 54 includes a support bracket 84 and a buckle 85. The lower end of the support bracket 84 is connected to the second support bracket 77 with bolts 86 and nuts. A buckle 85 is attached to the upper end of the support bracket 84.

As shown in FIG. 1, the tongue 88 of the seat belt 87 is inserted into the buckle 85. The tongue 88 of the seat belt 87 is locked to the buckle 85. As a result, the tongue 88 inserted into the buckle 85 is connected to the buckle 85.
According to this state, for example, when the impact load F1 is input from the front of the vehicle Ve, the occupant is kept restrained by the seat belt 87. At this time, a tensile load F2 acts on the tongue support portion 54 via the seat belt 87.

As shown in FIG. 5, the left side sill 14 includes a side sill outer 65, a side sill inner 66, and a stiffener 67. The side sill outer 65 is provided on the outer side in the vehicle width direction. The side sill inner 66 is provided inside the side sill outer 65 in the vehicle width direction. The stiffener 67 is interposed between the side sill outer 65 and the side sill inner 66.
The left side sill 14 is formed in the outer shape of a rectangular frame by the side sill outer 65 and the side sill inner 66.

As shown in FIGS. 6 and 7, the second floor cross member 35 is formed substantially symmetrically (see also FIG. 2). Therefore, the left side portion of the second floor cross member 35 will be described in detail below, and the description of the right side portion will be omitted.
The second floor cross member 35 includes an end member 171, a straight line member 172, and a center member 173 that are joined in order from the outside in the vehicle width direction toward the center.
The end member 171 is arranged on the left outer side in the vehicle width direction, and extends inward in the vehicle width direction from the left side sill 14. The straight portion member 172 extends inward in the vehicle width direction from the inner end portion of the end member 171. The central member 173 extends inward in the vehicle width direction from the inner end of the straight member 172. The central member 173 is arranged so as to straddle the floor tunnel 192 of the floor panel 16.

Further, the second floor cross member 35 includes an outer fastening bracket (fastening bracket) 141 and an inner fastening bracket (fastening bracket) 142.
The outer fastening bracket 141 is a member that constitutes a part of the outer fastening unit (fastening unit) 21A. The inner fastening bracket 142 is a member that constitutes a part of the inner fastening unit (fastening unit) 21B.

The first floor cross member 34 is provided in front of the vehicle body of the second floor cross member 35 at predetermined intervals. The first floor cross member 34 is formed substantially symmetrically like the second floor cross member 35.
Like the second floor cross member 35, the first floor cross member 34 includes an end member 301, a straight portion member 302, and a central portion member 303 that are joined in order from the outside to the center in the vehicle width direction. .. Further, the first floor cross member 34 includes an outer fastening bracket (fastening bracket) 304 and an inner fastening bracket (fastening bracket) 305.
The outer fastening bracket 304 is a member that constitutes a part of the outer fastening unit (fastening unit). The inner fastening bracket 305 is a member that constitutes a part of the inner fastening unit (fastening unit).

The end member 301 is formed in the same manner as the end member 171 of the second floor cross member 35. The straight portion member 302 is formed in the same manner as the straight portion member 172 of the second floor cross member 35. The central member 303 is formed in the same manner as the central member 173 of the second floor cross member 35.
Further, the outer fastening bracket 304 is formed in the same manner as the outer fastening bracket 141 of the second floor cross member 35. The inner fastening bracket 305 is formed in the same manner as the inner fastening bracket 142 of the second floor cross member 35.
Therefore, detailed description of the end member 301, the straight portion member 302, the central portion member 303, the outer fastening bracket 304, and the inner fastening bracket 305 of the first floor cross member 34 will be omitted.

As shown in FIG. 8, the end member 171 has an inclined portion 107 and a horizontal portion 175. The inclined portion 107 is arranged on the left side sill 14 side.
The inclined portion 107 has an upper inclined portion 108, a joint seat portion 177, and a bead 178.
The upper inclined portion 108 is a portion forming an upper portion of the inclined portion 107.
The joint seat portion 177 extends horizontally from the outer end portion 108a of the upper inclined portion 108 toward the outside in the vehicle width direction and is joined to the upper portion 82 of the left side sill 14.
Hereinafter, the upper portion 82 of the left side sill 14 is referred to as "side sill upper portion 82".

Here, the upper inclined portion 108 extends downward from the outer end of the horizontal portion 175 to the upper portion 82 of the side sill. Therefore, the boundary between the upper inclined portion 108 and the joint seat portion 177 is bent to form a bent portion 179 extending in the front-rear direction of the vehicle body. Therefore, when the impact load F3 is input from the side of the vehicle Ve, it is conceivable that the bent portion 179 is bent by the input impact load F3. Therefore, the bead 178 was extended in the vehicle width direction from the upper inclined portion 108 to the joint seat portion 177.

The bead 178 extends outward in the vehicle width direction from a portion 108b in the middle of the upper inclined portion 108 to the outer edge of the joint seat portion 177. The bead 178 is formed so as to bulge upward. A plurality of bead 178s are formed, for example, at intervals in the front-rear direction of the vehicle body. In the embodiment, an example in which two beads 178 are formed will be described, but the number of beads 178 can be arbitrarily selected. It is also possible to select one bead 178.

A bead 178 extends in the vehicle width direction from the upper inclined portion 108 to the outer edge of the joint seat portion 177. Therefore, the bead 178 is extended so as to intersect (specifically, orthogonal to) the bent portion 179. As a result, the bent portion 179 can be reinforced with the bead 178 against the impact load F3 input from the side of the vehicle Ve to the joint portion.
That is, the bead 178 can prevent the bent portion 179 from bending when the impact load F3 is input to the joint seat portion 177. As a result, the impact load F3 can be transmitted from the joint seat portion 177 to the upward inclined portion 108 via the bead 178, so that the load transmission is not impaired.

Here, the upper inclined portion 108 is a portion forming the upper portion of the inclined portion 107. The upper inclined portion 108 extends downward to the upper portion 82 of the side sill toward the outside in the vehicle width direction. The outer end of the inclined portion 107 is closed by the upper inclined portion 108.
The outer end 108a of the upper inclined portion 108 is located at the upper portion 82 of the side sill. The joint seat portion 177 is joined to the side sill upper portion 82 via the left side portion 16c of the floor panel 16. The member front flange 104 (specifically, the end 104a of the member front flange 104) and the member rear flange 105 (specifically, the end 105a of the member rear flange 105) of the end member 171 are the floor panel 16. It is joined to the left side portion 16c.
In this way, the outer end portion (that is, the joint seat portion 177) of the inclined portion 107 is joined to the side sill upper portion 82 via the left side portion 16c of the floor panel 16.

The horizontal portion 175 extends parallel to the floor panel 16 from the inner end portion 107a of the inclined portion 107 toward the inside in the vehicle width direction. The first rear fastening seat portion 25 is formed on the upper portion 175a of the horizontal portion 175. The first rear fastening seat portion 25 is formed on the end side of the second floor cross member 35 in the vehicle width direction. The first seat rail 56 of the passenger seat 32 (see FIG. 5) is attached to the first rear fastening seat portion 25 with bolts 41 and nuts 42.
The end member 171 is formed into a relatively complicated shape by closing the outer end portion of the inclined portion 107 with the upper inclined portion 108.

As shown in FIGS. 6 and 7, the inner end portion 171a of the end portion member 171 and the outer end portion 172a of the straight portion member 172 are joined in a superposed state. By joining the inner end portion 171a of the end portion member 171 and the outer end portion 172a of the straight portion member 172, the first joint portion 184 is formed by the overlapped inner end portion 171a and the outer end portion 172a. ing. An outer fastening bracket 141 is joined to the first joint portion 184.

As shown in FIGS. 8 and 9, the outer fastening bracket 141 has a bottom portion 185, an outer leg portion 186, an inner leg portion 187, an outer upper flange 188, and an inner upper flange 189.
The bottom portion 185 is arranged along the floor panel 16 and is fastened to the upper portion 133b of the outer fastening member 133 by bolts 165 and nuts 166 via the floor panel 16. The outer fastening member 133 is a member that constitutes a part of the outer fastening unit 21A (21).
The outer leg portion 186 is raised from the outer portion of the bottom portion 185 to the upper portion 175a of the horizontal portion 175 (that is, the inner end portion 171a of the end member 171). The inner leg portion 187 is raised from the inner portion of the bottom portion 185 to the inner end portion 172b of the straight portion member 172. The outer fastening bracket 141 is formed in a U-shaped cross section at the bottom portion 185, the outer leg portion 186, and the inner leg portion 187.

From the upper end of the outer leg portion 186, the outer upper flange 188 extends outward in the vehicle width direction along the outer surface of the inner end portion 171a. The outer upper flange 188 is joined to the first joint portion 184. Specifically, the outer upper flange 188 is joined in a state of being sandwiched between the inner end portion 171a of the end portion member 171 and the outer end portion 172a of the straight portion member 172. Therefore, the outer upper flange 188 of the outer fastening bracket 141 is firmly supported between the inner end portion 171a and the outer end portion 172a.
The bottom portion 185 of the outer fastening bracket 141 is fastened to the upper portion 133b of the outer fastening member 133 via the floor panel 16 by bolts 165 and nuts 166. The outer fastening bracket 141 is made of a high-strength member for supporting the battery pack 28. Therefore, the first joint portion 184 is reinforced by the outer upper flange 188.

The first rear fastening seat portion 25 is formed on the outside of the first joint portion 184 in the vehicle width direction and in the vicinity of the first joint portion 184. Therefore, the first seat rail 56 of the passenger seat 32 is attached by the bolt 41 and the nut 42 in the vicinity of the first joint portion 184 (that is, the outer upper flange 188).
From the upper end of the inner leg portion 187, the inner upper flange 189 extends inward in the vehicle width direction along the inner surface of the straight portion member 172. The inner upper flange 189 is joined to the straight line member 172.

As shown in FIGS. 7 and 10, the central member 173 is arranged so as to intersect (orthogonally) the floor tunnel 192 of the floor panel 16 and is attached so as to straddle the floor tunnel 192. The central portion member 173 has an upper portion 173b extending in the vehicle width direction and a raised portion 194 raised in the center in the vehicle width direction. A second rear fastening seat portion 26 is formed on the upper portion 173b of the central portion member 173. The second rear fastening seat portion 26 is formed on the center side of the second floor cross member 35 in the vehicle width direction. The second seat rail 57 of the passenger seat 32 is attached to the second rear fastening seat portion 26 with bolts 41 and nuts 42.

The raised portion 194 is formed in a U shape along the floor tunnel 192. That is, the raised portion 194 is formed in a relatively complicated shape.
The left end portion 173a of the central portion member 173 and the inner end portion 172b of the straight portion member 172 are joined in a superposed state. The left end portion 173a of the central portion member 173 and the inner end portion 172b of the straight portion member 172 are joined to form a second joint portion 196 between the left end portion 173a and the inner end portion 172b. An inner fastening bracket 142 is joined to the second joint portion 196.

The inner fastening bracket 142 has a bottom portion 202, an outer leg portion 203, an inner leg portion 204, an outer upper flange 205, and an inner upper flange 206, similarly to the inner fastening bracket 142.
The bottom portion 202 is arranged along the floor panel 16 and is fastened to the upper portion 134b of the inner fastening member 134 with bolts 167 and nuts 168 via the floor panel 16. The inner fastening member 134 is a member that constitutes a part of the inner fastening unit 21B (21). The outer leg portion 203 is raised from the outer portion of the bottom portion 202 to the inner end portion 172b of the straight portion member 172. The inner leg portion 204 is raised from the inner portion of the bottom portion 202 to the upper portion 173b of the central portion member 173. The inner fastening bracket 142 is formed in a U-shaped cross section at the bottom portion 202, the outer leg portion 203, and the inner leg portion 204.

An inner upper flange 206 extends inward in the vehicle width direction from the upper end of the inner leg portion 204 along the outer surface of the upper portion 173b of the central portion member 173. The inner upper flange 206 is joined to the second joint portion 196 in a state of being sandwiched between the left end portion 173a and the inner end portion 172b. Therefore, the inner upper flange 206 of the inner fastening bracket 142 is firmly supported between the left end portion 173a and the inner end portion 172b.
The bottom portion 202 of the inner fastening bracket 142 is fastened to the upper portion 134b of the inner fastening member 134 with bolts 167 and nuts 168 via the floor panel 16. The inner fastening bracket 142 uses a high-strength member to support the battery pack 28. Therefore, the second joint portion 196 is reinforced by the inner upper flange 206.

The second rear fastening seat portion 26 is formed inside the second joint portion 196 in the vehicle width direction and in the vicinity of the second joint portion 196. Therefore, the second seat rail 57 of the passenger seat 32 is attached by the bolt 41 and the nut 42 in the vicinity of the second joint portion 196 (that is, the inner upper flange 206).
From the upper end of the outer leg portion 203, the outer upper flange 205 extends outward in the vehicle width direction along the inner surface of the straight portion member 172. The outer upper flange 205 is joined to the straight portion member 172.

A raised portion 194 is formed in a U shape on the central portion member 173. Therefore, the central member 173 is formed in a relatively complicated shape.
On the other hand, the straight portion member 172 extends linearly from the end portion member 171 to the central portion member 173. Therefore, the straight portion member 172 is formed in a relatively simple shape.

Here, the end member 171 of the second floor cross member 35 is joined to the left side sill 14. Further, the central member 173 of the second floor cross member 35 is formed in accordance with, for example, the floor tunnel 192. Therefore, the end member 171 and the center member 173 are formed in a relatively complicated shape. On the other hand, the straight portion member 172 is suppressed to a relatively simple shape.
In this way, the second floor cross member 35 is divided into three members: an end member 171 and a straight line member 172, and a central member 173. Therefore, for example, the end member 171 and the center member 173 having a complicated shape can be drawn (drawed), and the straight member 172 having a simple shape can be bent (bent). By bending the straight portion member 172 in this way, the manufacturing cost of the second floor cross member 35 can be reduced.

Further, it is possible to optimize the collision mode by making the strengths of the end member 171, the straight line member 172, and the center member 173 different. In this case, a device for ensuring the strength of the first joint portion 184 (see FIG. 9) between the end member 171 and the straight portion member 172 and the second joint portion 196 between the straight portion member 172 and the central portion member 173 is required. Be done. Therefore, the outer fastening bracket 141 is joined to the first joint portion 184. Further, the inner fastening bracket 142 is joined to the second joint portion 196. The outer fastening bracket 141 and the inner fastening bracket 142 are made of high-strength members to support the battery pack 28.

Therefore, the outer fastening bracket 141 is joined to the first joining portion 184, and the inner fastening bracket 142 is joined to the second joining portion 196, so that the first joining portion 184 is reinforced by the outer fastening bracket 141 and the second joining is performed. The portion 196 is reinforced by the inner fastening bracket 142. As a result, the load transmission performance of the second floor cross member 35 in the vehicle width direction can be ensured, and the impact load F1 (see also FIG. 9) input from the side of the vehicle Ve is well supported by the second floor cross member 35. be able to.

As shown in FIGS. 2 and 6, in the first floor cross member 34, the first front fastening seat portion 23 is formed on the end member 301 and the first front fastening seat portion 23 is formed on the central portion member 303, similarly to the second floor cross member 35. 2 The front fastening seat portion 24 is formed. The first front fastening seat portion 23 is formed on the end side of the first floor cross member 34 in the vehicle width direction. The second front fastening seat portion 24 is formed on the center side of the first floor cross member 34 in the vehicle width direction.

The first front fastening seat portion 23 is formed on the outside of the first joint portion 197 in the vehicle width direction and in the vicinity of the first joint portion 197. Therefore, the first seat rail 56 (see FIG. 3) of the passenger seat 32 is attached with bolts 41 and nuts in the vicinity of the first joint portion 197 (that is, the outer upper flange 307 (see FIG. 7) of the outer fastening bracket 304). Has been done.
The second front fastening seat portion 24 is formed inside the second joint portion 198 in the vehicle width direction and in the vicinity of the second joint portion 198. Therefore, the second seat rail 57 (see FIG. 3) of the passenger seat 32 is attached with bolts 41 and nuts in the vicinity of the second joint 198 (that is, the inner upper flange 308 (see FIG. 7) of the inner fastening bracket 305). Has been done.

Returning to FIGS. 4 and 5, the inclined portion 107 has an upper inclined portion 108, a front wall portion (member front wall portion) 102, and a rear wall portion (member rear wall portion) 103. The front wall portion 102 extends from the front side of the upper inclined portion 108 to the floor panel 16. The rear wall portion 103 extends from the rear side of the inclined portion 107 to the floor panel 16.
The inclined portion 107 is formed in a U shape by the upper inclined portion 108, the front wall portion 102, and the rear wall portion 103.

A gusset 62 is arranged below the second floor cross member 35. The gusset 62 is erected on the inner wall 81 of the side silina 66 and the lower surface 16b of the floor panel 16. Hereinafter, the inner wall 81 of the side sill inner 66 is referred to as "side sill inner wall 81".
The gusset 62 has a gusset inclined portion 111, a gusset front wall portion 112, a gusset rear wall portion 113, and gusset flanges 116 and 118. The gusset inclined portion 111 extends downward from the lower surface 16b of the floor panel 16 to the inner wall 81 of the side sill toward the outside in the vehicle width direction.
The gusset front wall portion 112 extends from the front side of the gusset inclined portion 111 to the left side portion 16c of the floor panel 16. The gusset rear wall portion 113 extends from the rear side of the gusset inclined portion 111 to the left side portion 16c of the floor panel 16.

The gusset 62 is formed in a U shape by the gusset inclined portion 111, the gusset front wall portion 112, and the gusset rear wall portion 113. In the gusset 62, the gusset flange 116 and the gusset flange 118 are joined to the floor panel 16.
Further, the inclined portion 107 of the second floor cross member 35 is formed in a U shape by the upper inclined portion 108, the front wall portion 102, and the rear wall portion 103. In the inclined portion 107, the member front flange 104 and the member rear flange 105 are joined to the floor panel 16.
The member front flange 104 is joined to the gusset flange 116 via the left side portion 16c of the floor panel 16. The member rear flange 105 is joined to the gusset flange 118 via the left side portion 16c of the floor panel 16.
That is, the second floor cross member 35 and the gusset 62 are joined with the floor panel 16 interposed therebetween.

As described above, the second floor cross member 35 is formed in a U shape by the upper inclined portion 108, the front wall portion 102, and the rear wall portion 103. The gusset 62 is formed in a U shape by the gusset inclined portion 111, the gusset front wall portion 112, and the gusset rear wall portion 113. Further, the second floor cross member 35 and the gusset 62 are joined with the left side portion 16c of the floor panel 16 interposed therebetween.
Therefore, the second floor cross member 35 and the gusset 62 form a highly rigid closed cross section. As a result, the impact load F3 input from the side of the vehicle Ve can be transmitted from the left side sill 14 to the second floor cross member 35.

The first floor cross member 34 is joined to the first gusset 61 with the floor panel 16 interposed therebetween, like the floor cross member (that is, the second floor cross member) 35. Therefore, the first floor cross member 34 and the first gusset 61 form a highly rigid closed cross section. As a result, the impact load F1 input from the side of the vehicle Ve can be transmitted from the left side sill 14 to the first floor cross member 34.

As shown in FIGS. 3 and 5, a battery pack 28 is provided between the left side sill 14 and the right side sill 15 (see FIG. 2) and below the floor panel 16. The battery pack 28 includes a battery case 121 and a lid 122. The battery case 121 has a case wall portion 124, a case bottom portion 125, and a case flange 126.
The case wall portion 124 has a front wall, a rear wall, a left side wall 124a, and a right side wall. The case wall portion 124 is formed in a rectangular frame shape by the front wall, the rear wall, the left side wall 124a, and the right side wall.

The lower end of the case wall 124 is closed by the case bottom 125, and an opening 127 is formed at the upper end. The case flange 126 projects from the entire circumference of the opening 127 of the case wall portion 124 to the outside of the battery case 121.
A battery cross member (underfloor cross member) 131 is attached to the inside of the battery case 121 (that is, the inside 129 of the battery pack 28). The battery cross member 131 extends in the vehicle width direction inside 129 of the battery pack 28.

The battery cross member 131 is attached to the first floor cross member 34 (see FIG. 2) and the second floor cross member 35 by a plurality of fastening units 21.
Hereinafter, among the plurality of fastening units 21, a pair of fastening units 21 provided in the left half of the second floor cross member 35 will be described as a representative example. Hereinafter, the pair of fastening units 21 will be described as an outer fastening unit 21A and an inner fastening unit 21B for convenience.

As shown in FIG. 9, the outer fastening unit 21A includes an outer fastening bracket 141 and an outer fastening member 133.
As described above, the outer fastening bracket 141 is provided on the second floor cross member 35. The outer fastening member 133 is a member that fastens the battery cross member 131 to the outer fastening bracket 141. The outer fastening member 133 has a lower portion 133a and an upper portion 133b.
The lower portion 133a has a bolt 151 protruding downward. The lower 133a is fastened to the battery cross member 131 by screwing the nut 152 to the bolt 151 of the lower 133a.

As shown in FIG. 10, the inner fastening unit 21B includes an inner fastening bracket 142 and an inner fastening member 134.
The inner fastening bracket 142 is provided on the second floor cross member 35 as described above. The inner fastening member 134 is a member that fastens the battery cross member 131 to the inner fastening bracket 142. The inner fastening member 134 has a lower portion 134a and an upper portion 134b.
The lower portion 134a has a bolt 154 that projects downward. The lower 134a is fastened to the battery cross member 131 by screwing the nut 155 to the bolt 154 of the lower 134a.

As shown in FIG. 5, the battery 123 is housed inside the battery case 121. In this state, the opening 127 of the battery case 121 is closed from above by the lid 122. The lid 122 has a lid wall portion 135, a lid top 136, and a lid flange 137.
The lid wall portion 135 has a front wall, a rear wall, a left side wall 135a, and a right side wall. The lid wall portion 135 is formed in a rectangular frame shape by the front wall, the rear wall, the left side wall 135a, and the right side wall. That is, the lid wall portion 135 is formed in the same manner as the case wall portion 124.
The upper end of the lid wall 135 is closed by the lid top 136, and an opening 138 is formed at the lower end. The lid flange 137 projects from the entire circumference of the opening 138 of the lid wall 135 to the outside of the lid 122.

By superimposing the lid flange 137 on the case flange 126 from above, the lid flange 137 and the case flange 126 are sealed with a sealing member. Therefore, the opening 127 of the battery case 121 is closed by the lid 122. The battery 123 is housed in the internal 129 of the battery pack 28. In a state where the opening 127 of the battery case 121 is closed by the lid 122, the upper portion 133b of the outer fastening member 133 and the upper portion 134b of the inner fastening member 134 project upward from the opening 136a of the lid top 136a.

As shown in FIGS. 9 and 10, the upper portion 133b of the outer fastening member 133 has a bolt 165 projecting upward. By screwing the nut 166 to the bolt 165 of the upper 133b, the upper 133b is fastened to the bottom 185 of the outer fastening bracket 141.
Further, the upper portion 134b of the inner fastening member 134 has a bolt 167 protruding upward. By screwing the nut 168 to the bolt 167 of the upper 134b, the upper 134b is fastened to the bottom 202 of the inner fastening bracket 142.
Therefore, the battery pack 28 is fastened to the second floor cross member 35 via the outer fastening unit 21A and the inner fastening unit 21B. As a result, the battery pack 28 (underfloor mounting component) containing the battery 123 (see FIG. 5) is attached below the floor panel 16.

Here, the first seat rail 56 is attached to the first front fastening seat portion 23 (see FIG. 2) of the first floor cross member 34 and the first rear fastening seat portion 25 of the second floor cross member 35. .. The second seat rail 57 is attached to the second front fastening seat portion 24 (see FIG. 2) of the first floor cross member 34 and the second rear fastening seat portion 26 of the second floor cross member 35.
Therefore, the outer fastening bracket 141 in the vicinity of the first rear fastening seat portion 25 is reinforced by the first seat rail 56. The inner fastening bracket 142 in the vicinity of the second rear fastening seat portion 26 is reinforced by the second seat rail 57. That is, the rigidity of the outer fastening bracket 141 and the inner fastening bracket 142 is increased. As a result, the battery pack 28 is reliably held, and the holding strength of the battery pack 28 is satisfactorily secured.

In this state, the first seat rail 56 of the passenger seat 32 is attached by the bolt 41 and the nut 42 in the vicinity of the outer upper flange 188 of the outer fastening bracket 141. The outer upper flange 188 is joined in a state of being sandwiched between the first joint portions 184.
Further, a second seat rail 57 of the passenger seat 32 is attached by bolts 41 and nuts 42 in the vicinity of the inner upper flange 206 of the inner fastening bracket 142. The inner upper flange 206 is joined in a state of being sandwiched between the second joint portions 196.

As shown in FIG. 3, the tongue support portion 54 is connected to the second support bracket 77 of the second seat rail 57 with bolts 86 and nuts. The tongue 88 (see FIG. 1) of the seat belt 87 is locked to the buckle 85 of the tongue support portion 54. As a result, the occupant seated on the passenger seat 32 is suitably restrained by the seat belt 87 on the passenger seat 32.

Next, an example in which the tongue support portion 54 is supported by the vehicle body lower structure 12 when the impact load F4 is input from the front of the vehicle Ve will be described with reference to FIG.
As shown in FIG. 11, when the impact load F4 is input from the front of the vehicle Ve, the seat belt 87 keeps the occupant 320 restrained. At this time, a tensile load F5 acts on the tongue support portion 54 via the seat belt 87.

Here, the bottom portion 202 of the inner fastening bracket 142 is fastened to the inner fastening member 134. Further, the inner upper flange 206 of the inner fastening bracket 142 is fixed in the vicinity of the second rear fastening seat portion 26 on the second floor cross member 35.
In the inner upper flange 206, the inner upper flange 206 is sandwiched between the left end portion 173a of the central portion member 173 and the inner end portion 172b of the straight portion member 172. Therefore, the inner upper flange 206 (that is, the inner fastening bracket 142) is firmly supported between the left end portion 173a and the inner end portion 172b.

Further, the second rear fastening seat portion 26 of the second floor cross member 35 is formed on the central portion member 173. The tongue support portion 54 is connected to the second rear fastening seat portion 26 via the second seat rail 57.
Therefore, when the tensile load F5 acts on the tongue support portion 54, the tensile load F5 is reliably applied from the inner upper flange 206 to the battery cross member 131 via the inner fastening bracket 142 and the inner fastening member 134 (that is, the inner fastening unit 21B). Can be told to.

That is, the support strength of the tongue support portion 54 (that is, the seat belt 87) can be secured. Therefore, the tensile load F5 can be reliably supported by the two members of the second floor cross member 35 and the battery cross member 131 by using the inner fastening unit 21B. As a result, the occupant 320 can be suitably restrained by the seat belt 87.
In this way, the tensile load F5 is supported by the second floor cross member 35 and the battery cross member 131 of the two members. As a result, the tongue support portion 54 (that is, the seat belt 87) can be supported without increasing the rigidity of the second floor cross member 35 more than necessary.

Further, a second rear fastening seat portion 26 is formed on the center side of the second floor cross member 35 in the vehicle width direction. The second seat rail 57 is attached in the vicinity of the second rear fastening seat portion 26. The first rear fastening seat portion 25 is formed on the end side of the second floor cross member 35 in the vehicle width direction. The first seat rail 56 is attached in the vicinity of the first rear fastening seat portion 25.
Therefore, the rigidity of the second floor cross member 35 is sufficiently secured by the first seat rail 56 and the second seat rail 57. That is, when the tensile load F5 acts on the tongue support portion 54, the tensile load F5 can be more reliably supported by the two members, the second floor cross member 35 and the battery cross member 131. As a result, the support strength of the tongue support portion 54 (that is, the seat belt 87) can be satisfactorily secured.

Further, the first seat rail 56 is attached to the first front fastening seat portion 23 (see FIG. 2) of the first floor cross member 34 and the first rear fastening seat portion 25 of the second floor cross member 35. The second seat rail 57 is attached to the second front fastening seat portion 24 (see FIG. 2) of the first floor cross member 34 and the second rear fastening seat portion 26 of the second floor cross member 35.
Therefore, the rigidity of the first floor cross member 34 and the second floor cross member 35 is sufficiently secured by the first seat rail 56 and the second seat rail 57.
As a result, when the tensile load F5 acts on the tongue support portion 54, the tensile load F5 can be more reliably supported by the two members, the second floor cross member 35 and the battery cross member 131. That is, the support strength of the tongue support portion 54 (that is, the seat belt 87) can be satisfactorily secured.

In this way, the tensile load F5 is supported by two members, the second floor cross member 35 and the battery cross member 131. Further, the tongue support portion 54 (that is, the seat belt 87) is configured so that the support strength can be satisfactorily secured. As a result, the tongue support portion 54 (that is, the seat belt 87) can be supported more satisfactorily without increasing the rigidity of the second floor cross member 35 more than necessary.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the battery pack 28 is exemplified as an underfloor mounting component (that is, an in-vehicle component), but the present invention is not limited to this. As another example, a fuel tank, a fuel cell stack, or the like can be used as an underfloor mounting component.

Further, in the above embodiment, the battery cross member 131 has been exemplified as the underfloor cross member, but the present invention is not limited to this. As another example, it can be applied to other cross members arranged below the floor panel 16.

Further, in the above-described embodiment, the first seat rail 56 and the second seat rail 57 are exemplified as the pair of seat support portions, but the present invention is not limited to this. As another seat support portion, for example, it can be applied to a member that supports the seat in a fixed state.

Further, in the above-described embodiment, an example in which the battery cross member 131 is connected to the second floor cross member 35 has been described, but the present invention is not limited to this. As another example, it is also possible to connect the battery cross member 131 to the second floor cross member 35 and further connect the battery cross member to the first floor cross member 34.

Ve …… Vehicle 10 …… Body 12 …… Body substructure 16 …… Floor panel 21 (21A) …… External fastening unit (fastening unit)
21 (21B) ... Internal fastening unit (fastening unit)
23 …… First front fastening seat (fastening seat)
24 …… Second front fastening seat (fastening seat)
25 …… First rear fastening seat (fastening seat)
26 …… Second rear fastening seat (fastening seat)
28 …… Battery pack (underfloor mounting parts)
31 …… Driver seat (seat)
32 …… Passenger sheet (sheet)
34-36 ... 1st to 3rd floor cross members (floor cross members)
53 …… Seat mounting part 54 …… Tongue support part (belt support part)
56, 57 ... 1st and 2nd seat rails (1st and 2nd seat support parts)
87 …… Seat belt 88 …… Tongue 123 …… Battery 129… Inside the battery pack (inside the underfloor mounted parts)
131 ... Battery cross member (underfloor cross member)
133 ... External fastening member (fastening member)
134 ... Inner fastening member (fastening member)
141 ... External fastening bracket (fastening bracket)
142 ... Inner fastening bracket (fastening bracket)
171, 301 ... End member 172, 302 ... Straight line member 173, 303 ... Central member 184, 197 ... First joint 185, 202 ... Bottom 186, 203 ... Outer leg (leg)
187,204 ... Inner leg (leg)
188,307 ... Outer upper flange (flange)
206, 308 ... Inner upper flange (flange)
196, 198 ... Second joint F2, F5 ... Tensile load (load)

Claims (6)

In the underfloor structure where underfloor mounting parts are attached below the floor panel,
A floor cross member provided on the floor panel and extending in the vehicle width direction,
An underfloor cross member arranged below the floor cross member and attached to the underfloor mounting component,
A fastening unit that attaches the underfloor cross member to the floor cross member,
With a seat attached to the floor cross member,
The sheet is
A seat mounting portion capable of transmitting a load to the fastening unit by being mounted in the vicinity of the fastening unit among the floor cross members.
A belt support portion that is connected to the seat mounting portion and supports the seat belt is provided .
The seat mounting portion includes a pair of seat support portions provided at intervals in the vehicle width direction.
One of the pair of seat support portions is attached to the vehicle width direction center side with respect to the fastening unit on the vehicle width direction center side.
The other of the pair of seat support portions is attached to the end side in the vehicle width direction with respect to the fastening unit on the end side in the vehicle width direction.
The lower part of the car body is characterized by this. In the underfloor structure where underfloor mounting parts are attached below the floor panel,
A floor cross member provided on the floor panel and extending in the vehicle width direction,
An underfloor cross member arranged below the floor cross member and attached to the underfloor mounting component,
A fastening unit that attaches the underfloor cross member to the floor cross member,
With a seat attached to the floor cross member,
The sheet is
A seat mounting portion capable of transmitting a load to the fastening unit by being mounted in the vicinity of the fastening unit among the floor cross members.
A belt support portion that is connected to the seat mounting portion and supports the seat belt is provided.
The fastening unit is
With the fastening bracket provided on the floor cross member,
The fastening bracket is provided with a fastening member for fastening the underfloor cross member.
The fastening bracket
With a bottom that is arranged along the floor panel and fastened to the fastening member,
With the legs raised from the bottom,
The load is applied to the fastening seat portion by extending from the upper end of the leg portion along the floor cross member and being fixed in the vicinity of the fastening seat portion to which the seat mounting portion is fastened among the floor cross members. With a transmissible flange,
The lower part of the car body is characterized by this. The floor cross member
It has an end member, a straight part member, and a center part member that are joined in order from the outside to the center in the vehicle width direction.
The underfloor mounting component arranged below the floor panel is connected to the first joint portion between the end member and the straight portion member and the second joint portion between the straight portion member and the central portion member. To be joined to the fastening bracket
2. The vehicle body lower structure according to claim 2. The fastening seat portion of the floor cross member is formed on the central portion member.
The flange is sandwiched between the central member and the straight member.
The vehicle body lower structure according to claim 3, characterized in that. The fastening seat portion is provided on the vehicle width direction center side and the vehicle width direction end side of the floor cross member.
The seat mounting portion includes a pair of seat support portions provided at intervals in the vehicle width direction.
One of the pair of seat support portions is attached in the vicinity of the fastening member on the center side so as to reinforce the fastening member on the center side in the vehicle width direction.
The other of the pair of seat support portions is attached in the vicinity of the fastening member on the end side so as to reinforce the fastening member on the end side in the vehicle width direction.
The vehicle body lower structure according to any one of claims 2 to 4, characterized in that. The seat support portion is a seat rail that extends in the front-rear direction of the vehicle body so that the seat can be slidably moved in the front-rear direction of the vehicle body.
A pair of the floor cross members are arranged at least in the front-rear direction of the vehicle body.
The seat rail is attached to the fastening seat portion of the pair of floor cross members.
The vehicle body lower structure according to claim 5, characterized in that.

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