JP2977301B2 - Lower body coupling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting a lower part of a vehicle body, and more particularly, to a structure for connecting an underbody structure including a front floor and a front frame connected thereto to an upper body structure other than the underbody structure. The present invention relates to a coupling structure of a lower part of a vehicle body which is assembled and coupled from below.

[0002]

2. Description of the Related Art Conventionally, the body (white body) of an automobile
When assembling the vehicle, the underbody mainly composed of the floor member and the other upper body were integrally assembled, and then the outfitting such as the seat device was assembled to the underbody. Since the parts are installed from the side door opening, the workability of the outfitting work is reduced.

Therefore, recently, for example, Japanese Utility Model Application
As disclosed in Japanese Patent Publication No. 108183, an underbody structure mainly composed of a front floor and a front frame coupled to the front floor among floor members composed of a front floor, a center floor, and a rear floor, and an upper body structure other than this. Are separately assembled, and then the underbody structure is assembled relative to the upper body structure from below. In this structure, a flange portion is formed on a peripheral portion of a floor opening of an upper body structure, and a flange portion of an underbody structure is coupled to the flange portion.

On the other hand, in the lower structure of the vehicle body, a closed cross-sectional structure formed by a third cross member and a floor member is conventionally provided at the boundary between the front floor and the center floor. Referring to this closed cross section, FIG. 21
In the example shown in FIG. 3, the third portion is located above the rear end of the front floor 100 and the inclined portion 101a at the front end of the center floor 101.
The cross members 102 are connected to form a closed cross-sectional structure. In the example shown in FIG. 22 , the third cross member 1 is provided below the inclined portion 111a of the center floor 111 and the rear portion.
12 are combined to form a closed cross-sectional structure. In the example shown in FIG. 23 , the inclined portion 1 is also provided at the rear end of the front floor 120.
The inclined portion 120a and its front portion and the inclined portion 121a of the center floor 121 and its rear portion are formed in a closed sectional structure.

Further, as shown in these three figures, front frames 103, 113, 123 are connected to the lower surfaces of the left and right portions of the front floors 100, 110, 120, respectively.
On the lower surfaces of the left and right outer portions of the center floors 101, 111, 121, relatively small height rear frames 104.1 are provided.
14 and 124 are joined and extend along the lower side of the third cross member.
Is formed in a bent shape, and its front end is connected to the front frames 103, 113 and 123.

[0006]

In the structure of the conventional third cross member, it is necessary to form a bent portion at least at the front end of the center floor, and the third cross member is formed by utilizing this bent portion. Since the cross member is formed, the forming process of the floor member is complicated, the structure of the third cross member is complicated, and the assemblability is deteriorated. In addition, since the third cross member is configured by utilizing floor members having a small thickness, the rigidity and strength of the third cross member are reduced.
Also, since the rear frame has a small height and is formed in a bent shape below the third cross member, the rigidity and strength of the rear frame are reduced. In addition, the connecting structure between the third cross member, the rear frame, and the front frame is very complicated, and the front floor and the front frame belong to the underbody structure, and the rear frame belongs to the upper body structure. In such a case, it is difficult to connect the underbody structure and the upper body structure at the front end side portion.

An object of the present invention is to improve the rigidity and strength of the third cross member while simplifying its structure, and to improve the structure of the front end portion of the rear frame and its peripheral portion to replace the underbody structure with the upper body structure. An object of the present invention is to provide a coupling structure of a lower part of a vehicle body, which can improve an assembling property when assembling the vehicle body.

[0008]

Means for Solving the Problems] coupling structure of a vehicle body bottom according to Claim 1, the front floor and the front and rear coupled thereto
An underbody structure including a front frame oriented in a direction , and a lower body coupling structure that is assembled and coupled to an upper body structure other than the underbody structure from below, wherein the underbody structure is the upper surface of the rear end portion of the front floor is coupled to the cross member having a side wall portion of a pair of front and rear and the upper wall portion forms the front floor and closed cross section, said front frame
Is connected to the lower surface of the front floor to form a cross member
Forming a closed cross-section extending further to the rear, a front end of a center floor belonging to the underbody structure or the upper body structure is overlapped and joined to an upper surface of an upper wall portion of the cross member, and is connected to a lower surface of the center floor. Rear frame
The front ends of the robots are joined to form a closed section,
The front end of the closed cross section including the
The front end of the closed cross-section including the rear frame
Touch the top of the rear end of the closed section including the front frame.
It is characterized by being tangentially connected .

According to a second aspect of the present invention , in the first aspect of the present invention , the main part of the center floor between the left and right rear frames of the center floor is connected to belong to an underbody structure. outer center floor portion of the right and left sides of the center floor main unit is coupled to belong to the upper body structure, front end portions of the rear frame cross member and substantially flush with is coupled to the lower surface of the outer center floor portion, before Symbol Both ends of the cross member are joined to the side sill.

According to a third aspect of the present invention , in the connecting structure of the lower part of the vehicle body according to the second aspect of the present invention , a front portion of the outer center floor portion is provided.
The end is bolted to the upper surface of the upper wall of the cross member.
The inner part of the outer center floor is the center floor
Bolted to the outer frame
The outer part is bolted to the side sill and rear frame
The rear end of the closed cross section including the front frame is
It is characterized by being bolted to the rear frame .

According to a fourth aspect of the present invention , in the connecting structure of the lower part of the vehicle body according to the second aspect of the present invention , the front end portion of the rear frame is disposed in contact with the inside of the side sill and connected to the side sill. .

[0012]

According to the first aspect of the present invention , a cross member having an upper wall and a pair of front and rear side walls forms a closed cross section with the front floor on the upper surface of the rear end portion of the front floor of the underbody structure. And the front end of the center floor belonging to the underbody structure or the upper body structure is connected to the upper surface of the upper wall of the cross member so as to be overlapped with each other, so that the cross member and the closed member have a closed sectional structure. the front floor and the rear floor it unnecessary to form the bent shape structure of these floors simplified, assembling property when assembled in the closed sectional structure is remarkably improved in.

Further, since a cross member having an upper wall portion and a pair of front and rear side wall portions is connected to the upper surface of the front floor to form a closed cross-sectional structure, the cross member is made of a member having a greater thickness than the front floor. The rigidity and strength can be increased by forming a closed cross-sectional structure mainly by a cross member having a wall and a pair of front and rear side walls. Front frame
Is extended to the rear beyond the cross member
And the front end of the closed section including the rear frame
The upper surface of the rear end of the closed section including the front frame
Closed, including the front frame,
Of the cross section and the cross section including the cross member and the rear frame
The bonding strength increases.

According to the second aspect of the invention , basically the same operation as that of the first aspect is obtained, and the main part of the center floor between the left and right rear frames belongs to the underbody structure. Because they are joined
By expanding the underbody structure backward, it is possible to improve the assembling property at the time of assembling the body and the fitting property at the time of assembling the upper body structure before the underbody structure and the upper body structure are combined.

The outer center floor portions on the left and right sides of the main portion of the center floor are joined so as to belong to the upper body structure, and the lower surface of the outer center floor portion has substantially the same height (substantially the same height) as the cross member. ), The front end of the rear frame is joined and the front end is in contact with the cross member. Therefore, the rear frame is enlarged to increase its rigidity, and the rear frame is bent at the lower side of the closed cross-section structure. Therefore, the structure can be simplified by forming a straight line without forming the lower body, the rigidity and strength can be increased, and the assemblability when the underbody structure is assembled to the upper body structure can be improved. Since both ends of the cross member are joined to the side sills, and the joint strength between the rear frame and the cross member is also enhanced as described above, the joint strength between the cross member, the side sill and the rear frame can be significantly enhanced, and The performance against the impact load can be improved.

According to the third aspect of the invention , basically the same operation as in the second aspect is obtained, and the vicinity of the cross member is obtained.
Of under body structure and upper body structure
Bolt connection is used to connect both body structures.
The joining operation at the time of joining is simplified.

According to the fourth aspect of the present invention , basically the same operation as that of the second aspect is obtained, and the front end side portion of the rear frame is disposed in contact with the inside of the side sill and is connected to the side sill. As a result, the bonding strength between the rear frame and the side sill can be enhanced.

[0018]

As explained in detail in the above-mentioned operation section,
The following effects can be obtained. According to the invention of claim 1,
It is not necessary to form the front floor and the rear floor in a bent shape in order to form the cross member and the closed cross-sectional structure, so that the structure of these floors is simplified, and assembly when the cross member is assembled into the closed cross-sectional structure. The properties are significantly improved. In addition, the rigidity and strength can be increased by forming a closed cross-sectional structure mainly composed of a cross member made of a member having a larger plate thickness than the front floor and having an upper wall and a pair of front and rear side walls. And the front frame
Closed section including the arm extends to the rear beyond the cross member
And the front end of the closed section including the rear frame
Part above the rear end of the closed section including the front frame
Includes front frame because it is abutted to the surface
Closed section including closed section, cross member and rear frame
Increases the bonding strength.

According to the second aspect of the present invention , basically the same effect as that of the first aspect is obtained, and the underbody structure is expanded rearward so that the upper body before the underbody structure and the upper body structure are joined. It is possible to improve the assemblability of the body and the outfitting of the outfitted components with respect to the structure. In addition, the rear frame is increased in size to increase its rigidity, and the rear frame is formed in a straight line without forming a bent shape below the closed cross-sectional structure, thereby simplifying the structure and increasing its rigidity and strength. In addition, the assemblability when the underbody structure is assembled to the upper body structure can be improved. Further, the coupling strength between the cross member, the side sill, and the rear frame can be remarkably enhanced, and the performance particularly against a rear impact load can be improved.

According to the third aspect of the invention , basically the same effects as those of the second aspect can be obtained, and the vicinity of the cross member can be obtained.
Connection between underbody structure and upper body structure
Both body structures are joined because bolt joints are adopted at the joints
Combining work at the time of the you simplify. According to the fourth aspect of the invention , basically the same effects as those of the second aspect can be obtained, and the coupling strength between the rear frame and the side sill can be enhanced.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a coupling structure of a lower part of a vehicle body of a four-door sedan type automobile. As shown in FIG. 1 and FIG. 2, the vehicle body of the automobile has a pre-assembled underbody structure BD (shown by hatching in FIG. 2) and a pre-assembled upper body structure BU.
Is assembled by assembling and connecting the components from below. It should be noted that the underbody structure BD and the upper body are equipped with outfitting parts such as a seat device, a transmission lever and a seatbelt, and the upper body structure BU is equipped with various outfitting parts. Assume that the structure BU is assembled.

The underbody structure BD includes a front floor 10, left and right front frames 11 provided on the lower surface of the front floor 10 in a front-rear direction, and a shaft tunnel 12 belonging to the front floor 10 and provided at the center of the upper surface. A side sill inner body 13 at both left and right ends of the front floor 10; and second cross members 1 provided at the front and rear ends of the front floor 10 in the left and right directions, respectively.
4th and 3rd cross members 15 and main center floor 1
6 (corresponding to the main part of the center floor).

The upper body structure BU has a structure other than the underbody structure BD, and includes a front body 1 including a shroud panel 2, a pair of left and right front side frames 3, a wheel apron 4, a cowl / dash structure 5, and the like. A rear floor 24, a pair of left and right closing plates 31, which are left and right sides of the center floor,
A left and right pair of rear frames 23, a fourth cross member, a rear end panel, a rear body including a package tray structure, a left and right pair of body side panels 6 each including a side sill 40, a roof panel 7, and the like are provided.

Next, the underbody structure BD will be described with reference to FIG. 3 and FIGS. However, since the body structure is symmetrical, only the left portion will be described. As shown in FIG. 3, a floor extension 10 a that protrudes outward is integrally formed on the front floor 10, and a rear end portion is formed on the lower surface of the front floor 10 as shown in FIGS. 5 to 7 and 10. There front frame 11 extending to the rear end of the front floor 10 is joined with the left and right flange portions 11a, the front frame 11 and the front floor
10 and close to extend rearward from the third cross member 15
A cross section is formed. On the upper surface of the front floor 10 corresponding to the inner end of the floor extension 10a, a side sill inner body 1 extending to near the rear end of the front floor 10
3 are joined by a flange portion 13a .

On the upper surface near the rear end of the front floor 10, there is a third cross member 15, which is made of a member having a greater thickness than the front floor 10, and includes an upper wall portion 15a and a pair of front and rear side wall portions 15b. A third cross member 15 having a trapezoidal shape with an open bottom surface having a
Are joined to the upper surface of the front floor 10, and the left end flange portion 15d and the left end front and rear flange portions 15e are joined to the flange portion 13b of the side sill inner body 13 and the upright wall portion 13c of the side sill inner body 13, respectively. Third cross member 1 further inside by a predetermined distance
The front end of the main center floor 16 is joined to the upper wall 15a of the fifth floor 5.

By configuring the underbody structure BD in this way, a closed cross-sectional structure is formed by the third cross member 15 and the front floor 10 as shown in FIG. The rear frame 2 includes a front floor 10, a side sill inner body 13, a third cross member 15, and a main center floor 16.
An accommodation space 18 in which the front end of the third unit 3 can be disposed is formed.
Reference numeral 10b denotes a cutout formed in the floor extension 10a.

Next, not the general structure of the upper body structure BU but a structure unique to the present invention will be described. However, since the structure is bilaterally symmetric, a portion that is coupled to the left portion of the rear portion of the underbody structure BD will be described. FIG.
As shown in FIG. 5, the side sill outer 25 and the side sill reinforcing plate 26 and the side sill inner upper 29 shorter than the side sill outer 25 are joined so as to form a closed cross-sectional structure. Rear frame 2 that is substantially the same height as cross member 15 and that is horizontal
3 is provided on the front end side .

The left flange 23 of the rear frame 23
The front end of the side sill reinforcing plate 2 as shown in FIG.
6 is joined to the upper surface of the flange portion 34 which is a joint portion between the side sill upper 29 and the side sill reinforcing plate 2.
The bottom wall 23b of the rear frame 23 on the rear side from
-As shown in FIG. 9, it is connected to the side sill outer 25 via the connecting plate member 30.

At the upper end of the rear frame 23, a closing plate 31 (which is substantially the same width as the rear frame 23 in the left-right direction and has a front end portion extending forward from the front end portion of the rear frame 23) is provided at the outer center floor portion. Corresponding), and the closing plate 31 is configured as shown in FIGS.
As shown in FIG. 9, while being joined to the upper surfaces of the left and right flange portions 23 a of the rear frame 23, the right front part and the right rear part thereof are joined to the side sill inner upper 29 and the side sill outer 25, respectively, and the side sill outer 2.
5 respectively. Also, the rear frame 23 and
A closed cross-section is formed with the loading plate 31 and will be described later.
Under body structure BD and upper body structure like
When the BU and the BU are connected, the rear frame 23 is included.
The front end of the closed cross section includes the front frame 11
It is coupled to the upper surface of the rear end portion of the cross section in a contact state.

When the under body structure BD and the upper body structure BU configured as described above are assembled and connected to each other, the under body structure BD is moved relative to the upper body structure from below, and the rear frame 23 is moved. Is fitted into the storage space 18 and the joint 33 between the side sill outer 25 and the side sill reinforcing plate 26 and the connecting plate member 30 are mounted on the floor extension 10a. In this assembled state, the front end of the rear frame 23 is in contact with the rear side wall 15 b of the third cross member 15, and the front end of the rear frame 23 is the vertical wall of the side sill inner body 13. 13c, the front end of the closing plate 31 overlaps the upper wall 15a of the third cross member 15, the right end of the closing plate 31 overlaps the right end of the main center floor 16, and the connecting plate member 30 At the right end is the floor extension 1
0a is engaged with the notch 10b.

Next, as shown in FIGS. 5 to 10, the front floor extension 10a, the joint 33 and the connecting plate 30
And the side sill inner body 13 is fastened to the joint 34 between the side sill reinforcing plate 26 and the side sill inner upper 29, the rear frame 23 and the closing plate 31 with bolts 52, and the front floor extension 10a Connecting plate member 30 and side sill outer 25
And side sill reinforcing plate 26 and side sill inner upper 29
Side sill 40 consisting of side sill inner body 13
Are formed in a closed cross-sectional structure.

As shown in FIGS. 6 and 10, the front end of the closing plate 31 is fastened to the upper wall portion 15a of the third cross member 15 with bolts 53, so that the closing plate 31 and the side sill inner body 13 are connected to each other. The rear frame 23 is connected to the third cross member 15 through the main center floor 1 as shown in FIGS.
6, the rear frame 23 and the closing plate 31 are fastened with a plurality of bolts 54, and the front floor 10 and the rear frame 23 are fastened with a plurality of bolts 55. still,
It is assumed that an adhesive for sealing is applied in advance to a portion where the upper body structure BU and the under-body structure BD are required to be sealed, and then bonded.

The operation of the thus assembled lower body coupling structure will be described. The third cross member 15 and the front floor 10 are joined to form a closed sectional structure,
Since this closed cross-sectional structure is mainly composed of the third cross member 15 having a large plate thickness, its rigidity and strength can be increased. Further, since the front end of the main center floor 16 is overlapped with and joined to the upper wall 15a of the third cross member 15, the front floor 10 and the main center floor are formed to form a closed cross-sectional structure at the third cross member 15. The floor 16 does not need to be formed in a bent shape,
16 is simplified, and the assemblability of the underbody structure BD and the upper body structure BU is significantly improved.

In addition, since the main center floor 16 is connected so as to belong to the underbody structure BD, the underbody structure BD can be enlarged rearward to form a large floor opening, and the underbody structure BD and the upper body It is possible to improve the body assembling property of the upper body structure BU before the connection with the structure BU and the outfitting property when assembling outfitting components. Further, the closing panel 31 which is a part of the center floor is connected so as to belong to the upper body structure BU, and the front end side portion of the rear frame 23 having substantially the same height as the third cross member 15 is connected to the lower surface of the closing panel 31. The rear frame 23
The rear frame 23 can be formed linearly without forming a bent shape below the closed cross-sectional structure, by increasing the size of the rear frame 23.
Structure can be simplified and rigidity and strength can be increased. Underbody structure BD and upper body structure BU
Can be improved.

Further, both ends of the third cross member 15 are connected to the side sill inner body 13 constituting the side sill 40, and the closing panel 31 is connected to the side sill inner body 1.
3 through the rear frame 23 and the third cross member 15
And the rear frame 23 is disposed in contact with the inside of the side sill inner main body 13 and the rear frame 23 and the side sill inner main body 13 are connected, so that the rear frame 23, the third cross member 15, the side sill Can significantly increase the bonding strength, and in particular, improve the performance against a rear impact load.

<Alternative Embodiment> As shown in FIGS. 11 and 12, the joint structure of the lower part of the vehicle body of this embodiment is such that the left and right rear frames 23A are arranged with a space between the side sill 40A and the rear frame. The frame 23A is connected to a side sill 40A via a torque box member 50.
The same members as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.

First, the underbody structure BDA will be described. As shown in FIG. 13, the side sill inner body 13A extends rearward from the rear end of the front floor 10A, and has a rectangular dish-like shape provided on the lower surface of the front floor 10A near the rear end of the front floor 10A. Front floor 10A from base 61 and right end of base 61
A rear frame junction 60 including a junction portion 62 that is inclined upwardly through an insertion hole (not shown) formed in the front floor 10A is provided by a flange portion 61a, 61b, 61c. The junction 62 is connected to the rear side wall 15 b of the third cross member 15 and the main center floor 16.
Are joined by flange portions 62a and 62b, respectively. By configuring the underbody structure BDA in this manner, as shown in FIGS.
5 and the front floor 10A constitute a closed cross-sectional structure,
At the rear end of the underbody structure BDA, the front end portion of the rear frame 23 is arranged by the front floor 10A, the side sill inner body 13A, the third cross member 15, the main center floor 16, and the junction portion 62 of the rear frame junction 60. An accommodating accommodation space 18A is formed.

Next, a description will be given of a general structure unique to the present invention in the upper body structure BUA similarly to the above. As shown in FIG. 14, the side sill outer 25, the side sill reinforcing plate 26A and the side sill inner upper 29A of the same length are joined so as to form a closed cross-sectional structure, and are provided inside the rear end of the side sill reinforcing plate 26. Is the third
A box-shaped torque box member 70 having substantially the same height as the cross member 15 and having open upper ends and both left and right end surfaces is disposed, and the third cross member 15 is provided inside the torque box member 70.
A front end portion of the rear frame 23A having substantially the same height as that of the torque box 70 is provided as shown in FIGS.
Are the flanges 70a, 70b, 70c and the rear frame 2
3A, the rear frame 23A and the upper end of the torque box member 70.
Closing plate 31 extending forward from the front end portion of the are arranged, as shown in FIGS. 15 to 17, closing plate 31 is joined and in contact <br/> engagement portion 32 is joined to the rear frame 23A I have.

The underbody structure BDA and the upper body structure BU configured as described above move the underbody structure BDA relatively downward with respect to the upper body structure, and the front end portion of the rear frame 23A and the torque. The box member 70 is fitted into the housing space 18A and assembled. In this assembled state, the front end of the rear frame 23A is in contact with the rear side of the third cross member 15, and the right side of the front end of the rear frame 23A is the junction of the rear frame junction 60. 6
2, and the torque box member 70 comes into contact with the side sill inner body 13A.

Next, as shown in FIGS. 15 to 19, the front floor extension 10a and the joining portion 33 are fastened with a plurality of bolts 71, and the side sill inner body 13A and the joining portion 3 are joined together.
The side sill 40 </ b> A is formed into a closed cross-sectional structure by fastening the closing sill 4 and the closing plate 31 with bolts 72. As shown in FIGS. 15, 18, and 19, the front end of the closing plate 31 is
And the front end of the bottom wall of the rear frame 23A is fastened to the third cross member 15a.
And the front floor 10A with bolts 77, thereby connecting the rear frame 23A to the third cross member 15 via the closing plate 31, the torque box member 70, and the side sill inner body 13A.
As shown in FIG. 17, the main center floor 16, the rear frame 23, the closing plate 31, and the junction 62 are fastened and connected by bolts 74, and the torque box member 70 is connected to the front floor 10 </ b> A and the base of the rear frame junction 60. 61 is fastened with bolt 75
Then, the torque box member 70, the side sill inner body 13A, and the front floor 10A are fastened and connected by bolts 76.

As described above, by coupling the torque box 70 to the side sill inner body 13A, the rear frame 23A is coupled to the side sill 40A via the torque box member 70. Rigidity can be improved.
The cross-sectional shape of the third cross member 15 is not limited to a trapezoidal shape. A joining flange is formed on the inner wall of the front end of the rear frames 23 and 23A, and the flange is connected to the third cross member 15. Alternatively, a front end wall may be formed at the front end portions of the rear frames 23 and 23A and bolted to the third cross member 15 (in this case, a bolt runner is attached to the front side wall portion of the third cross member 15). It is also possible to provide an insertion hole). Also, the rear portions of the rear frames 23 and 23A need not necessarily have the same cross-sectional shape as the front portions.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an underbody structure and an upper body structure according to an embodiment of the present invention .

FIG. 2 is a schematic plan view of a lower part of a vehicle body.

FIG. 3 is a perspective view of a main part of an underbody structure.

FIG. 4 is a perspective view of a main part of an upper body structure.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 2;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 2;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 2;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 2;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 2;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 2;

FIG. 11 is a diagram corresponding to FIG. 1 according to another embodiment.

FIG. 12 is a diagram corresponding to FIG. 2 according to another embodiment.

FIG. 13 is a diagram corresponding to FIG. 3 according to another embodiment.

FIG. 14 is a diagram corresponding to FIG. 4 according to another embodiment.

FIG. 15 is a sectional view taken along line 15-15 of FIG. 12;

FIG. 16 is a sectional view taken along line 16-16 of FIG. 12;

FIG. 17 is a sectional view taken along line 17-17 of FIG. 12;

18 is a sectional view taken along line 18-18 of FIG.

19 is a sectional view taken along line 19-19 of FIG.

FIG. 20 is a sectional view taken along the line 20-20 in FIG. 12;

FIG. 21 is a cross-sectional view of a lower part of a vehicle body according to a conventional technique.

FIG. 22 is a cross-sectional view of a lower part of a vehicle body according to the related art.

FIG. 23 is a cross-sectional view of a lower part of a vehicle body according to a conventional technique.

[Explanation of symbols]

 BD / BDA Underbody structure BU / BUA Upper body structure 10.10A Front floor 11 Front frame 13.13A Side sill inner body 15 Third cross member 15a Upper wall 15b Side wall 16 Main center floor 23 Rear frame 31 Rear frame closing plate 40 / 40A side sill 70 torque box member

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Inoue 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-1-182175 (JP, A) JP-A-2- 37087 (JP, A) Hira 2-45885 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B62D 25/20

Claims (4)

(57) [Claims] 1. A front floor and front and rear coupled thereto
The underbody structure including a front frame oriented in the direction is connected to the upper body structure other than the underbody structure relative to the lower body from below, and the underbody structure is combined with the upper body structure. A cross member having an upper wall and a pair of front and rear side walls is coupled to the upper surface of the rear end portion of the front floor so as to form a closed sectional structure with the front floor, and the front frame is coupled to the lower surface of the front floor.
To form a closed section that extends to the back of the cross member
And the front end portion of the center floor belonging to the underbody structure or the upper body structure is coupled by overlapping the upper surface of the upper wall of the cross member, the front end portion of the rear frame to the underside of the center floor
Combined to form a closed section, including its rear frame
The front end of the closed cross section is in contact with the cross member, and the front end of the closed cross section including the rear frame is the front end.
Abuts on the upper surface of the rear end of the closed section including the frame.
Coupling structure of underbody, characterized in that engagement is was. 2. A center floor main portion between the left and right rear frames of the center floor is connected to belong to an underbody structure, and outer center floor portions on both left and right sides of the center floor main portion have an upper body structure. coupled to belong to the lower surface of the outer center floor portion are combined front end portion of the rear frame cross member and substantially flush with, both ends of the cross member, characterized in that coupled to the side sill The lower body coupling structure according to claim 1. 3. A front end of the outer center floor portion is a front end.
Bolted to the upper surface of the upper wall of the cross member
The inner part of the center floor is the main part of the center floor and the rear
Bolted to the frame and outside the outer center floor
The side is bolted to the side sill and rear frame,
The rear end of the closed section including the front frame
The lower body coupling structure according to claim 2, wherein the vehicle body is bolted to the arm . 4. The coupling structure for a lower part of a vehicle body according to claim 2, wherein a front end side portion of the rear frame is disposed in contact with the inside of the side sill and coupled to the side sill.