CN100467332C - Substructure - Google Patents

Abstract

A pair of right and left floor frames (10) extending in the front-rear direction and sandwiching a tunnel section (6) are joined to the bottom surface of a front floor section (2), cross members (15, 16) extending in the vehicle width direction and connecting a side member (7) and the tunnel section (6) are joined to the upper surface of the front floor section (2), and the floor frames (10) are inclined so as to gradually approach the inside in the vehicle width direction as they extend rearward, and are inclined with respect to the cross members (15, 16) in plan view. When the floor frame (10) is displaced rearward in the event of a frontal collision, a compression action is exerted on a portion of the cross members (15, 16) that is further to the outside in the vehicle width direction than the floor frame (10), and a tension action is exerted on a portion that is further to the inside in the vehicle width direction than the floor frame. With the vehicle body lower section structure of the present invention, the impact generated at the time of a frontal collision can be effectively received by the cross member.

Description

Substructure

technical field

The present invention relates to a vehicle body substructure.

Background technique

Regarding the vehicle body of an automobile, its floor includes a front floor portion having a pair of left and right side beams connected and a tunnel portion (Tunnel portion) extending in the front-rear direction at the central part in the vehicle width direction; from the rear of the front floor portion a rear upwardly curved portion extending upward; and a rear floor portion extending substantially linearly rearward from the upper end of the rear upwardly curved portion. Generally, a pair of left and right floor frames extending in the front-rear direction and sandwiching the tunnel portion are joined to the bottom surface of the front floor portion, and the side beams and the tunnel portion are joined to the upper surface of the front floor portion. And a beam extending along the width of the vehicle.

A pair of left and right front frames are arranged in the front of the base plate, viewed from above, the base frame is located on the rear extension line of the front frame, and is connected to the front end of the base frame with respect to the rear end of the front frame, so that when a frontal collision occurs, the transmission Rearward loads are efficiently transferred from the front frame to the floor frame.

The above-mentioned floor frames are generally arranged to be parallel to the front-rear direction axis of the vehicle body, and extend straight in a straight line, and are arranged to be orthogonal to the above-mentioned beams in a top view. Patent Document 1 (Japanese Patent Laid-Open Publication No. Hei 11-78959) discloses a structure in which a pair of left and right floor frames are tilted so as to gradually move toward the inside in the vehicle width direction as they extend rearward. Therefore, no disclosure is made about the technical significance of the above-mentioned inclination of the floor frame. The technology disclosed in Patent Document 1 is characterized in that an auxiliary frame provided between a pair of left and right front frames is formed in a front-opening, roughly triangular, unique structure in plan view. Considering the shape of the auxiliary frame, Correspondingly, the pair of left and right front frames are also formed as a front-opening type (the inclination is set so as to gradually approach the outside in the vehicle width direction as it extends forward), so only the floor frame is located on the rear extension line of the front-opening front frame superior.

However, in the event of a frontal collision, the rearward impact load input to the pair of left and right front frames is transmitted to the floor frame, but the rearward load input to the floor frame is mechanically weak as a material for the beam. Therefore, there are some problems that need to be solved in the aspect of effectively using the beam to deal with the impact.

Contents of the invention

The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a vehicle body substructure that can effectively withstand the impact generated in a frontal collision by effectively utilizing a beam.

In order to achieve the above object, the lower structure of the vehicle body of the present invention has a bottom plate that connects a pair of left and right side beams and has a front floor portion that extends in the front-rear direction at the center of the vehicle width direction; from the front floor portion a rear upward curved portion extending upward from the rear end; and a rear floor portion extending substantially linearly rearward from the upper end of the rear upward curved portion; the bottom surface of the front floor portion is joined with a A pair of left and right floor frames provided for the front floor portion, the front floor portion is joined to a cross member extending in the vehicle width direction and connected to the side beam and the tunnel portion, the front end of each floor frame is connected to the left and right pair of front frames and its rear end extends to the vicinity of the rear upward curve, the floor frame is inclined to gradually approach the inner side of the vehicle width direction as it extends rearward, and is inclined relative to the cross member in a plan view.

With the above vehicle body lower structure, when a frontal collision occurs, the floor frame that receives the load transmitted from the front frame to the rear will be displaced rearward. A compressive action is exerted on the outer portion in the width direction, and a tensile action is exerted on a portion located on the inner side in the vehicle width direction than the floor frame. In this way, the crossbeam can withstand the load generated when the frontal collision occurs through strong compression and stretching of the material mechanics, so the load generated when the frontal collision occurs can be effectively borne by the crossbeam. In addition, by installing the floor frame at a slant, a longer floor frame length can be ensured compared with a structure in which the floor frame is arranged straight and parallel to the front-rear axis of the vehicle body, thereby improving the effect of absorbing shocks by the floor frame itself.

In the above vehicle body substructure, preferably, the front portion of the floor frame is formed of high-tensile steel and the rear portion thereof is formed of ordinary steel, and the front portion of the floor frame extends rearward in plan view and is aligned with the The beams cross.

With the above-mentioned underbody structure, the floor frame that receives the load transmitted to the rear caused by a frontal collision can disperse the load while moving backwards, and the front part that requires high plastic deformation strength is made of high-tensile steel, so Buckling can be avoided and loads can be efficiently transferred to the beam with the setback described above. In addition, since the rear part of the floor frame with a small setback amount is made of cheap ordinary steel, it is ideal in terms of cost reduction.

In the vehicle body lower structure described above, a connection member extending in the vehicle width direction and connecting the rear end portions of the pair of left and right floor frames may be provided near the rear upward curve.

By adopting the above-mentioned vehicle body lower structure, the rear end of the floor frame can be prevented or restrained from being greatly displaced rearward by providing the connecting member. When the fuel tank is arranged behind the floor frame, the protection of the fuel tank is ideal. Furthermore, the rigidity of the vehicle body as a whole can be improved by connecting the rear end portions of the pair of left and right floor frames with the connecting member. In addition, since the distance between the rear end portions of the pair of left and right floor frames is smaller than the distance between the front end portions, the connecting member can be a member having a shorter length in the vehicle width direction.

In the vehicle body lower structure described above, the connection members may be respectively engaged with the front floor portion at left and right positions in the vicinity of the tunnel portion and sandwiching the tunnel portion.

According to the vehicle body lower structure described above, the rigidity of the vehicle body can be sufficiently ensured by effectively using the connecting member to prevent large cracks in the tunnel portion in the vehicle width direction.

In the above vehicle body lower structure, the floor frame may be formed by interconnecting the front portion of the floor frame and the rear portion of the floor frame, and has a pair of left and right side wall portions, and a portion connecting the lower ends of the pair of left and right side wall portions. The bottom wall portion and the left and right pair of flange portions extending from the upper ends of the left and right pair of side wall portions are generally in the shape of an inverted hat in cross section, and the front end portion of the rear portion of the floor frame is formed with downward and sideward The enlarged enlarged part, the rear end part of the front part of the floor frame, is fitted in the enlarged part of the rear part of the floor frame, and in this state, the front part of the floor frame is engaged with the rear part of the floor frame .

With the above vehicle body lower structure, the cross-section of the floor frame can be in the shape of an inverted hat, and at the same time, the front part and the rear part of the floor frame can be firmly connected.

In the above vehicle body lower structure, the cross member may include a first cross member disposed approximately in the middle of the front floor portion in the front-rear direction; and a second cross member disposed between the first cross member and the rear upward curved portion. Beams; the floor frame can be inclined relative to the first beam and the second beam when viewed from above.

According to the vehicle body lower structure described above, the front and rear two sets of beams arranged at regular intervals in the front and rear directions can effectively bear the load generated in the event of a frontal collision, respectively.

In the above vehicle body lower structure, each of the beams may be joined to the upper surface of the front floor at its front and rear pair of flanges, and each of the floor frames may be connected at its left and right flanges respectively. joint with the bottom surface of the front floor part, and each flange part of each beam and each flange part of the left and right pair of floor frames can be connected with the front floor at the positions where they intersect each other in plan view. The bottom plate parts are joined together in a state of overlapping three pieces.

According to the above vehicle body lower structure, the cross member, the floor frame and the front floor portion can be joined by the flange portion, and the load from the floor frame can be efficiently transmitted to the cross member through the three overlapping joint parts.

In the above vehicle body lower structure, the pair of left and right front frames may extend parallel to each other in the front-rear direction, and the distance between the front ends of the pair of left and right floor frames may be set to be equal to that of the pair of left and right front frames. Backend spacing is about the same.

With the above vehicle body lower structure, a pair of left and right front frames can be arranged parallel to each other extending in the front-rear direction, so that the engine and the like can be arranged between the left and right pair of front frames as in the past, and at the same time, the The load generated during a frontal collision is efficiently transmitted from the pair of left and right front frames to the floor frame.

In the vehicle body lower structure described above, it may further include: a load beam that is joined to the front floor portion and extends in the vehicle width direction to intersect with each of the floor frames; and is provided below the rear floor portion and along A pair of left and right rear frames extending in the front-rear direction; the load beams can be respectively connected to the rear ends of the floor frames and the front ends of the rear frames, and the front ends of the rear frames can be connected to the rear ends of the side beams. The ends are connected, and the load beam can be formed into an arched shape that is generally protruding forward in a plan view.

With the above-mentioned underbody structure, in the event of a frontal collision, the rearward load transmitted to the front frame can also be transmitted to the load beam, but the load beam can withstand the force generated by the frontal collision through strong compression in material mechanics load, so that the load beam can further effectively bear the load generated in the event of a frontal collision. That is, when there is an input of load transmitted to the rear, the load beam tries to deform from an arched shape to a straight shape along the vehicle width direction, but a relatively large resistance to the above-mentioned deformation occurs, so that the load beam can be passed more reliably. To withstand the load transmitted to the rear. In addition, in the above structure, the load beam is also connected to the rear frame, so that the rear frame, which conventionally does not receive the load transmitted from the floor frame to the rear, can also receive the load transmitted to the rear.

In the vehicle body lower structure described above, a pair of left and right rear frames provided under the rear floor portion and extending in the front-rear direction may be further included; and a connecting frame joined to the bottom surface of the front floor portion; the rear The front end of the frame can be connected to the rear end of the side beam, the rear end of the connecting frame can be connected to the front end of the rear frame, and the front end is arranged at the intersection of the floor frame and the cross beam Corresponding to the position of the bottom surface of the front bottom plate.

With the above-mentioned vehicle body lower structure, the rear end of the floor frame is set at a considerable distance from the side sill by inclination setting, so in the front floor, between the side sill and the floor frame and from the rear upward bend to the position where it is located NVH (Noise, Vibration, Harshness) problems may occur in the specified area of the beam directly in front. However, with this configuration, the portion of the predetermined area can be reinforced by the connecting frame, so that the occurrence of the above-mentioned NVH problem can be reduced. In addition, the impact load input to the floor frame and transmitted to the rear can also be received by the rear frame through the connecting frame, thereby improving the strength of the vehicle body. In addition, the connection frame can withstand the load generated by the input side beam in the event of a side impact, and this side impact load can also be transmitted to the floor frame, so it can also effectively respond to side impacts.

By adopting the present invention, the load generated when a frontal collision occurs can be further effectively supported by the beam. Also, the floor frame can be made as long as possible to enhance its impact-absorbing effect.

Description of drawings

FIG. 1 is a plan view showing an embodiment of the present invention.

Fig. 2 is a sectional view of line 2-2 in Fig. 1 .

Fig. 3 is a perspective view showing the arrangement relationship of strength members such as a floor frame, a cross beam, a side beam, and a rear frame in Fig. 1 .

Fig. 4 is a perspective view showing a connection state of a floor frame, a front frame, and side members.

Fig. 5 is a schematic view showing the connection relationship between the floor frame, the beam, and the front floor, which is a cross-sectional view along line 5-5 in Fig. 6 .

Fig. 6 is a schematic view of the intersection of the floor frame and the beam viewed from above.

Fig. 7 is a perspective view of the intersection of the floor frame and the beam viewed from below (the front floor portion is omitted).

Fig. 8 is an exploded perspective view showing the connection relationship between the front part and the rear part of the floor frame.

Fig. 9 is a side view showing the connecting portion of the front and rear of the floor frame.

Fig. 10 is a schematic diagram showing the positional relationship and joint relationship between the front and rear parts of the floor frame and the beam, and is a sectional view taken along line 10-10 in Fig. 7 .

Fig. 11 is a plan view showing main parts of another embodiment of the present invention.

Fig. 12 is a sectional view along line 12-12 in Fig. 11 .

Fig. 13 is a plan view of the connecting member shown in Fig. 11 .

Fig. 14 is a cross-sectional view along line 14-14 in Fig. 13 .

Fig. 15 is a schematic diagram showing still another embodiment of the present invention, and is a cross-sectional view corresponding to Fig. 12 .

Fig. 16 is a schematic diagram showing another embodiment of the present invention, and is a plan view corresponding to Fig. 1 .

Fig. 17 is a cross-sectional view along line 17-17 in Fig. 16 .

Fig. 18 is a perspective view of details near the rear end of the floor frame viewed from below.

Fig. 19 is a perspective view showing an example of an arched beam.

Fig. 20 is a sectional view along line 20-20 in Fig. 18 .

Fig. 21 is a sectional view of line 21-21 in Fig. 18 .

Fig. 22 is a sectional view along line 22-22 in Fig. 18 .

Fig. 23 is a schematic diagram illustrating a transmission form of a load transmitted rearward to a fourth beam.

Fig. 24 is a schematic diagram showing still another embodiment of the present invention, and is a plan view corresponding to Fig. 1 .

Fig. 25 is a sectional view of line 25-25 in Fig. 24 .

Fig. 26 is a schematic view showing details of the vicinity of the connection frame, and is a perspective view in which the bottom plate is omitted.

Fig. 27 is a perspective view showing an example of a fifth beam.

Fig. 28 is a sectional view along line 28-28 in Fig. 26 .

Fig. 29 is a sectional view along line 29-29 in Fig. 26 .

Fig. 30 is a sectional view along line 30-30 in Fig. 26 .

Detailed ways

In Fig. 1 and Fig. 2, 1 is a bottom plate, which is formed by joining together a plurality of panel materials formed by dividing along the front-rear direction. The bottom plate 1 generally includes a front bottom plate portion 2; a rear upward curved portion 3 that rises shortly upward from the rear end of the front bottom plate portion 2, and a rear bottom plate portion 4 that extends rearward from the upper end of the rear upward curved portion 3. . The front end of the front floor portion 2 extends in the vertical direction, and is connected to the lower end of a partition 5 that partitions the vehicle compartment and the engine compartment.

The front floor part 2 is formed with a channel part 6 extending in the front-rear direction at the central part in the vehicle width direction. connected (opening to the rear). The left and right end portions of the front floor portion 2 are joined to a pair of left and right side beams 7 as strength members extending in the front-rear direction.

A fuel tank 8 is provided immediately behind the rear upward curve 3 and directly below the rear floor 4 . At a rear position of the fuel tank 8 , that is, on the rear floor portion 4 , a housing portion 9 protruding downward is formed, and a spare tire and the like can be accommodated in the housing portion 9 .

In FIGS. 1 to 3 , a pair of left and right floor frames 10 are joined to the bottom surface of the front floor portion 2 , and the channel portion 6 is located between the pair of left and right floor frames 10 . That is, each floor frame 10 is located between the tunnel portion 6 and the side member 7 in the vehicle width direction. The floor frame 10 extends linearly in the front-rear direction as a whole, but is inclined with respect to the vehicle body front-rear direction axis. That is to say, the pair of left and right floor frames 10 are inclined so as to gradually move toward the inner side in the vehicle width direction (closer to the tunnel portion 6 ) as they extend rearward, and the distance between the front ends in the vehicle width direction is set to be greater than The distance between its rear end in the vehicle width direction. In addition, the inclination angles of the pair of left and right floor frames 10 are equal. The cross-sectional shape of the floor frame 10 is formed in an inverted hat shape opened upward as described below, and a closed cross section is formed by being joined to the front floor portion 2 .

Also as shown in FIG. 4 , the front ends of the pair of left and right floor frames 10 are directly joined and connected to the rear ends of the pair of left and right front frames 11 . That is, the pair of left and right front frames 11 are parallel to each other, and also parallel to the axis of the front and rear direction of the vehicle body (not inclined in plan view), the distance between the rear ends of the pair of left and right front frames 11 in the vehicle width direction is , which is substantially the same as the distance between the front ends of the pair of left and right floor frames 10 in the vehicle width direction. In addition, since the installation method of the front frame 11 is the same as the conventional one, the same structure as the conventional one can be used for supporting the engine (power transmission system) by the front frame 11 .

The rear end of the front frame 11 is positioned more rearward than the front end of the side sill 7, and the rear end of the front frame 11, the front end of the side sill 7, and the front end of the floor frame 10 use a torsion box as a strength member. (torque box) 12 are interconnected.

Two sets of front and rear beams 15 and 16 are joined to the upper surface of the front floor portion 2 . That is, the first beam 15 located on the front side is provided at approximately the middle position in the front-rear direction of the front floor portion 2, and the second beam 16 located at the rear side is provided approximately at the middle position between the first beam 15 and the rear upward curved portion 3. Location. Each beam 15 , 16 is divided into two parts at the portion of the tunnel portion 6 along the vehicle width direction, and each beam 15 , 16 connects the inner surface of the side member 7 and the outer surface of the tunnel portion 6 . The cross-sections of the beams 15 and 16 are substantially hat-shaped opening downward, and are joined to the front floor portion 2 to form a closed cross-section. The beams 15 and 16 extend perpendicularly to the front-rear direction axis of the vehicle body as in the prior art, and are arranged obliquely with respect to the floor frame 10 in plan view.

A pair of left and right rear frames 17 extending in the front-rear direction are joined to the bottom surface of the rear floor portion 4 . The front end of the rear frame 17 is joined to the rear end of the side member 7 . The left and right pair of rear frames 17 are connected between the fuel tank 8 and the housing portion 9 by a third beam 18 extending in the vehicle width direction. The cross-sectional shape of the rear frame 17 is an inverted hat shape opening upward, and is joined to the rear floor portion 4 to form a closed cross-section.

Next, referring to FIGS. 5 to 7 , the joining relationship between the beams 15 , 16 and the floor frame 10 with respect to the front floor portion 2 will be described in detail. First, the floor frame 10, as shown in FIGS. 5 and 7, has a pair of left and right side wall portions 10a, a bottom wall portion 10b connecting the lower ends of the left and right pair of side wall portions 10a, and a bottom wall portion 10b extending from the left and right pair of side walls. The upper end of the portion 10a is a pair of left and right flange portions 10c extending substantially horizontally. The floor frame 10 is joined (welded in the embodiment) to the front floor portion 2 in a state where each flange portion 10c is in contact with the bottom surface of the front floor portion 2 (the front floor portion 2 is not shown in FIG. 7 ). .

The joining methods of the beams 15 and 16 to the front floor portion 2 and the floor frame 10 are the same, and the first beam 15 will be described here. First, the first beam 15 has a pair of front and rear side wall portions 15a, an upper wall portion 15b connecting the upper ends of the front and rear pair of side wall portions 15a, and a substantially horizontally extending bottom end of the front and rear pair of side wall portions 15a. A pair of front and rear flange portions 15c. The first beam 15 is joined (welded in the embodiment) to the front floor portion 2 in a state where each flange portion 15c is in contact with the upper surface of the front floor portion 2 (the front floor portion 2 is omitted in FIG. 7 ). Show).

1, 6, and 7, the left and right flanges 10c of the floor frame 10 and the front and rear flanges 15c of the crossbeam 15 (the same for the crossbeam 16) have a total of four crossings in plan. The crossing portions are joined to each other, and the joining portion is indicated by a symbol α in FIGS. 5 and 6 . That is, in particular, as can be seen from FIG. 5 , in a state where the front floor portion 2 is sandwiched between the flange portion 10c of the floor frame 10 and the flange portion 15c of the beam 15 (16), the respective flange portions 10c and 15c are connected to the front. The bottom plate portion 2 is joined to each other in a state where three are overlapped (welded joint in the embodiment).

In the structure described above, the impact load generated during a frontal collision first acts on the front frame 11 , is then transmitted from the front frame 11 to the floor frame 10 , and is also transmitted to the side member 7 through the torsion box 12 . The floor frame 10 to which a collision load is input absorbs the impact by the floor frame 10 itself and the front floor portion 2 joined thereto. At the same time, the floor frame 10 displaced rearward by the impact load also transmits the impact load to the beams 15 and 16 , so that the impact can be absorbed by the beams 15 and 16 as described below. In addition, since the floor frame 10 is installed at an inclination, the overall length can be increased compared with a structure not inclined (a structure arranged parallel to the axis of the front-rear direction of the vehicle body), so that the floor frame 10 itself can absorb impacts and interact with the floor. Absorption of impact by the front floor portion 2 joined by the frame 10 can be performed more effectively.

Since the floor frame 10 is inclined relative to the beams 15, 16, the impact load is transmitted from the floor frame 10 to the beams 15, 16 from a direction inclined relative to the vehicle width direction axis of the beams 15, 16. That is, among the beams 15 , 16 , a compressive force acts on a portion on the side beam 7 side relative to the floor frame 10 , and a tensile force acts on a portion on the tunnel portion 6 side relative to the floor frame 10 . Since the beams 15 and 16 have a large resistance against compressive force or tensile force, they can more effectively withstand the impact load transmitted rearward than conventional cases where only bending force or shearing force is applied.

Among the two sets of front and rear beams 15 , 16 , the impact load transmitted from the floor frame 10 to the rear is larger for the first beam 15 located in the front than for the second beam 16 located in the rear. That is, the rearward impact load transmitted to the rearward second beam 16 is relatively small, so that large rearward displacement of the rear end of the floor frame 10 can be prevented or suppressed.

Next, other preferred embodiments of the present invention will be described with reference to FIG. 8 and subsequent drawings. First, FIGS. 8 to 10 show an example in which the material of the floor frame 10 is changed between the front portion 10A and the rear portion 10B. That is, in order to transmit a large impact load, the front portion 10A of the floor frame 10, which requires high plastic deformation strength, is made of high-tensile steel, while the rear portion 10B, which transmits only a small impact load compared with the front portion 10A, is made of cheap steel. common steel. Furthermore, the rear end portion of the front portion 10A and the front end portion of the rear portion 10B are connected by a method described later. The rear end of the front portion 10A of the floor frame is located approximately in the middle of the second beam 16 in the front-rear direction (the connection position between the front portion 10A and the rear portion 10B in FIG. 10 is located in the approximate middle of the second beam 16 in the front-rear direction). Accordingly, the floor frame 10 (the front portion 10A thereof) does not undergo buckling, and the impact load can be reliably transmitted to the second beam 16 positioned behind.

The connection between the front portion 10A and the rear portion 10B of the floor frame 10 may be, for example, butt welding, but the connection strength can be further ensured by fitting as described below. That is, the enlarged portion 25 is formed at the front end portion of the floor frame rear portion 10B, and welding is performed in a state where the rear end portion of the floor frame front portion 10A is fitted in the enlarged portion 25 . The enlarged portion 25 slightly shifts the flange portion 10c and the bottom wall portion 10b of the bottom frame rear portion 10B downward, and slightly shifts the pair of left and right side wall portions 10a outward. Thus, when the rear end portion of the floor frame front portion 10A is fitted into the enlarged portion 25, in parts other than the enlarged portion 25, each portion of the front portion 10A and the rear portion 10B (the left and right side wall portions 10a, the bottom wall) The flange part 10b and the left and right flange parts 10c) are smoothly connected to each other in a state of being positioned on the same plane.

As shown in FIG. 10, in the second beam 16, the flange portion 16c located on the front side is joined to the flange portion 10c of the front portion 10A of the floor frame (the joining portion is indicated by symbol α), and the flange portion 16c located on the rear side is joined to the flange portion 10c of the front portion 10A of the floor frame. The flange portion 10c of the floor frame rear portion 10B is joined (the joint portion is indicated by symbol α). In this way, the second beam 16 can also serve as a connection member between the front portion 10A and the rear portion 10B of the floor frame, so that the connection strength between the front portion 10A and the rear portion 10B can be further improved.

11 to 14 show examples in which a connection member is provided for connecting the rear end portions of a pair of left and right floor frames 10 . That is, as shown in FIG. 11 , a connecting member 30 extending in the vehicle width direction is provided between the second cross member 16 and the rear upturned portion 3 , and the rear ends of the pair of left and right floor frames 10 can be connected by the connecting member 30 . . As shown in FIGS. 12 to 14 , the connection member 30 has a large bending rigidity by forming, for example, a ferrous metal plate by press forming a rib portion 30 a extending in the vehicle width direction. Attachment holes 30 b are formed at two left and right positions at the ends of the connecting member 30 in the vehicle width direction (see FIG. 13 ).

The connecting member 30 is fixed to the floor frame 10 in a state where the end portion in the vehicle width direction is in contact with the bottom surface (bottom wall portion) of the floor frame 10 . That is, the connection member 30 can be fixed to the floor frame 10 by fixing the nut 31 to the floor frame 10 in advance and screwing the bolt 32 penetrating through the attachment hole 30 b to the nut 31 . The peripheral portion of the above-mentioned mounting hole 30b in the connecting member 30 is set at a relatively high position, and the head of the above-mentioned bolt 32 does not protrude below the lowest position of the connecting member 30 (refer to FIGS. 12 and 14 to prevent the head of the bolt 32 from part directly in contact with the raised part of the road surface).

By providing the connecting member 30 , it is possible to prevent or restrain the rearward displacement of the rear end of the floor frame 10 when a frontal collision occurs (especially when a sideways collision occurs). Furthermore, by providing the connection member 30, the cracking of the tunnel part 6 can be prevented or suppressed, and the rigidity of a vehicle body, especially torsional rigidity can be improved. In addition, since the distance between the rear ends of the pair of left and right floor frames 10 is small, the connection member 30 can also be a short member.

As shown in FIG. 12 , the connecting member 30 extends linearly in the vehicle width direction when viewed from the front-rear direction, and straddles (the lower opening of) the channel portion 6 (that is, connects to the left and right side walls and the upper wall portion of the channel portion 6 ). member 30 below). That is, when an exhaust pipe or the like is provided in the inner space of the duct portion 6 , the connection member 30 can also be provided after the exhaust pipe or the like is installed. In addition, the connection member 30 is located in the vicinity of the channel portion 6 and at positions on the left and right sides of the channel portion 6. Protruding portions protruding upward are respectively provided. parts to join). At this time, the cracking of the tunnel portion 6 can be further prevented or suppressed, so that the rigidity of the vehicle body can be improved.

FIG. 15 shows a modified example of the connection member 30 described above. That is, the connection member 36 in FIG. 15 connects the rear end portions of the pair of left and right floor frames 10, and this structure is the same as that of the connection member 30 shown in FIGS. 11 to 14 . In the example of FIG. 15 , the connection member 36 may be formed of, for example, a ferrous metal plate, and extends along the bottom surface of the front floor portion 2 and the inner surface of the tunnel portion 6 . That is, the structure of the connecting member 36 is the same as that in which the thickness of the front floor portion 2 and the tunnel portion 6 located between the pair of left and right floor frames 10 are thickened. The above-mentioned connecting member 36 overlaps the front floor portion 2 and the floor frame 10 together with the front floor portion 2 and the floor frame 10 in a state of being sandwiched between the front floor portion 2 and the floor frame 10 (the flange portion 10 c ) at its end in the vehicle width direction. The state is to be welded (the joint is indicated by the symbol α). Furthermore, the connecting member 36 is welded to the front floor portion 2 at positions located near the tunnel portion 6 and on the left and right of the tunnel portion 6 (joint portions are denoted by reference numeral α). Thereby, cracking of the passage portion 6 can be prevented or suppressed.

16 and 17 show examples in which the load beam 61 is provided. In addition, the same structure as the above-mentioned embodiment is given the same code|symbol, and the description is abbreviate|omitted.

As shown in FIGS. 16 and 17 , the rear end portion of each floor frame 10 is joined to a load beam provided near the rear upward curve 3 , that is, a fourth beam 61 . The fourth beam 61 extends in the vehicle width direction and has an arched shape protruding forward in plan view.

A specific structure of the fourth beam 61 will be described with reference to FIGS. 18 to 22 . First, the fourth beam 61 has a shape as shown in FIG. 19 as a whole, and has an inverted hat-shaped section joined to the bottom surface of the front floor portion 2 . Reference numeral 61d denotes a flange portion for engagement with the front floor portion 2 . The rear portion of the flange portion 61d has an arched shape that protrudes forward and has a large area in plan view, and the rear wall portion 61e extends upward from the rear end of the flange portion 61d located on the rear side. Furthermore, a flange portion 61f is formed at the upper end of the rear wall portion 61e as a joining portion with the bottom surface of the rear floor portion 4 .

The fourth beam 61 is joined to the bottom surface of the front floor portion 2 by its flange portion 61d (refer to FIG. 18, FIG. 20, and FIG. , Figure 21). In this way, the fourth beam 61 constitutes a closed cross section together with the rear upward curve 3 . Moreover, the vehicle width direction end part of the 4th cross member 61 is also joined to the side member 7 (refer FIG. 22).

The portion of the fourth beam 61 having a substantially inverted hat-shaped cross-section has an arc shape centered on a central point set at the rear of the vehicle body. The center point may be set at the intersection of the longitudinal axis passing through the center of the vehicle body in the vehicle width direction and the rearward extension of each floor frame 10 . FIG. 23 shows the point at which the load is transmitted rearward at the intersecting portion of the floor frame 10 and the fourth beam 61 set above. In addition, FIG. 23 simplifies the floor frame 10 and the fourth beam 61 and only shows the axes. As can be seen from FIG. 23 , at the intersection with the floor frame 10 , the load transmitted from the floor frame 10 to the rear is distributed and transmitted to the left and right rears to the fourth beam 61 , and the load distributed to the left and right rear becomes the force to compress the fourth beam 61. directional force.

In FIG. 23 , a dotted line is a virtual line Y passing through the intersection of the floor frame 10 and the fourth beam 61 and perpendicular to the axis of the floor frame 10 . The fourth beam 61 is located further back with respect to the imaginary line Y. As shown in FIG. If another way of observation is adopted, the fourth beam 61 is gradually positioned at the rear in the axial direction of the floor frame 10 as it moves away from the axis of the floor frame 10 .

The load transmitted from the floor frame 10 to the rear is also input to the fourth beam 61, and the fourth beam 61 receiving the load transmitted to the rear, as described above, is subjected to a strong compressive action in terms of material mechanics, so that it can reliably withstand the rearward direction. transmitted load. In addition, the load transmitted rearward from the floor frame 10 can also be transmitted to the pair of left and right rear frames 17 through the fourth beam 61, so that the load transmitted rearward can be reliably received. Of course, the use of the fourth beam 61 can not only greatly increase the rigidity of the vehicle body, but also can bear the load generated in the event of a side collision, thereby better responding to the side collision. In addition, the retreat of the floor frame 10 that occurs when a frontal collision occurs can be prevented or suppressed by the fourth cross member 61, thereby effectively protecting the fuel tank 8 and the like.

The 4th beam 61 shown in Fig. 18～Fig. 22 can also be set to only have the part that is substantially inverted hat shape in cross-section, does not form closed section together with back curved part 3 (only forms closed section together with front floor part 2). profile). At this time, under the front floor portion 2, a large space located directly behind the fourth beam 61 and protruding forward is formed, so that the fuel tank 8 can be extended in the large space to increase the capacity of the fuel tank 8. .

24 to 30 show examples in which the connection member 40 is provided. In addition, the same structure as the said embodiment is given the same code|symbol and the description is abbreviate|omitted.

In this embodiment, as shown in FIGS. 24 and 25 , the front ends of a pair of left and right rear frames 17 are connected by a rear cross member extending in the vehicle width direction, that is, a fifth cross member 41 . The rear end portions of the floor frames 10 are connected to the fifth beam 41 . The fifth beam 41 has a shape as shown in FIG. 27 as a whole, and is joined to the rear frame 17 by the flanges 41c at its left and right ends, and is connected to the rear of the front floor 2 by the flanges 41d at its lower end. The bottom surface of the end part is joined, and the bottom surface of the front end part of the rear floor part 4 is joined by the flange part 41e located in the upper end part. The fifth beam 41 constitutes a closed section together with the rear end portion of the front floor portion 2 , the rear upward curve portion 3 , and the front end portion of the rear floor portion 4 .

As shown in Fig. 24 and Fig. 26, the intersection part of the rear end of the floor frame 10 and the second beam 16 is connected to the front end of the rear frame 17 through the connecting frame 40 (the rear end of the connecting frame 40 is inclined in the embodiment). The mode of abutting is connected with the front end of rear frame 17). That is, the connecting frame 40 has an inverted hat shape in cross-section as a whole, and is joined to the bottom surface of the front floor portion 2 by the flange portion 40c, and is also joined to the inner surface of the side member 7 by the flange portion 40c.

Next, the connection frame 40 and the fifth beam 41 will be described in detail with reference to FIG. 26 and subsequent drawings. First, as shown in FIGS. 26 and 28 , the two members 41 and 10 are joined in such a way that the rear end of the floor frame 10 abuts against the front surface of the lower end of the fifth beam 41 (the cross-sectional shape of the fifth beam 41 roughly as shown in Figure 28 over its full length). That is, a connection form in which the impact load transmitted rearward from the floor frame 10 can be efficiently input to the fifth beam 41 is formed.

26 , FIG. 29 , and FIG. 30 show connection forms of the connection frame 40 and the fifth beam 41 with respect to the rear frame 17 . That is, the front end portion of the rear frame 17 is joined to the rear end portion of the side member 7 . The flange portion 40 c of the connection frame 40 is joined to the inner side surface and the bottom surface of the rear frame 17 and is also joined to the inner side surface of the side member 7 . This constitutes a connection form in which the impact load input into the connection frame 40 and transmitted rearward is not only directly transmitted to the rear frame 17 but also directly transmitted to the side member 7 . In particular, the rear end of the link frame 40 is connected in oblique contact with the front end of the rear frame 17, so that the impact load transmitted rearward can be transmitted from the link frame 40 to the rear frame 17 extremely efficiently.

The fifth beam 41 is joined to the inner surface of the rear frame 17 by its flange portion 41c. Specifically, part of the flange portion 41c of the fifth beam 41 is joined to the rear frame 17 in a three-fold state via the part of the flange portion 41c of the connection frame 40 . In addition, as shown in FIG. 26, a working hole 17a for welding is opened in the bottom surface of the front end of the rear frame 17 to facilitate the joining work.

Here, by providing the connecting frame 40, the front bottom plate portion 2 is located in front of the rear upturned portion 3 (fifth beam 41), behind the second beam 16, inside of the side beam 7, and the tunnel portion 6 in plan view. The part of the specified area of the foreign party can be fully strengthened. That is, the above-mentioned predetermined area portion includes the first triangular portion surrounded by the floor frame 10, the fifth beam 41, and the connecting frame 40, and the second triangular portion surrounded by the connecting frame 40, the side beam 7, and the second beam 16. The triangular part thus constitutes a very high-strength (rigidity) structure as a whole. Further, the installation position of the second beam 16 is a position connected to the lower end portion of the B pillar (not shown) in the vehicle body front-rear direction. The above-mentioned two triangular parts constitute the mounting part of the B-pillar, that is, the base part, thereby constituting an extremely high-strength structure.

However, among the two sets of front and rear beams 15, 16, the impact load transmitted from the floor frame 10 to the rear is larger for the first beam 15 located in the front than for the second beam 16 located in the rear. That is, the rearward impact load transmitted to the rearward second beam 16 is relatively small, so that large rearward displacement of the rear end of the floor frame 10 can be prevented or suppressed. In addition to this, the fifth beam 41 can further reliably prevent or suppress the rear end of the floor frame 10 from retreating.

In addition, the impact load input into the floor frame 10 and transmitted rearward is effectively received by the side members 7 and the rear frame 17 via the connecting frame 40 , and is also effectively received by the fifth cross member 41 . Furthermore, when a side collision occurs, the side load can be effectively received by the connecting frame 40 and the fifth beam 41 , and can also be effectively received by the floor frame 10 through the connecting frame 40 . In this way, frontal rear-end collisions and side collisions can be effectively dealt with.

Some embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and can be appropriately modified within the scope described in the claims. For example, the following configurations can be employed. The floor frame 10 may be made of the same material over its entire length (for example, high-tensile steel may be used over its entire length). Viewed from above, the cross beams intersecting the floor frame 10 may not be limited to 2 groups, and may also be 1 group or 3 groups or more. The beams 15 and 16 may be provided on the bottom surface of the front floor portion 2 . The fourth beam 61 may be joined to the upper surface of the front floor portion 2 . The 5th beam 41 can adopt a shorter structure in the vertical direction to avoid contact between its upper end and the rear floor portion 4, and only forms a closed section between the rear end portion of the front floor portion 2 and the lower end portion of the rear upward curve 3. In addition, the fifth beam 41 may not be used. Of course, the object of the present invention is not limited to the contents of the express description, but actually also includes other structures that provide ideal or advantages.

Claims (9)

1, a kind of automobile underbody structure is characterized in that:

The base plate of this automobile underbody structure has, and connects the curb girder of pair of right and left and has the noseplate portion of the channel part that extends along fore-and-aft direction at overall width direction central part; The back turn of bilge of going up that extends upward from the rear end of this noseplate portion; And the back base plate that the upper end of turn of bilge rearward roughly extends straight on from this back;

The bottom surface of described noseplate portion engages to have along fore-and-aft direction and extends and clip described channel part and the pair of right and left chassis that is provided with,

Described noseplate portion, engage have along the overall width direction extend and with described curb girder and channel part bonded assembly crossbeam,

Described each chassis, its front end engages with the rear end of the front baffle of pair of right and left, and its rear end extends to described back and go up near the turn of bilge,

Described chassis tilts for relying on overall width direction inboard gradually along with rearward extending, and tilts with respect to described crossbeam by overlooking observation,

Described chassis, its front portion is formed by high tension steel, and its rear portion is formed by ordinary steel,

The front portion of described chassis is by overlooking that observation is rearward extended and intersecting with described crossbeam.

2, automobile underbody structure as claimed in claim 1 is characterized in that,

Described back go up turn of bilge near, be provided with the transom of rearward end that extends and connect the chassis of described pair of right and left along the overall width direction.

3, automobile underbody structure as claimed in claim 2 is characterized in that,

Described transom near described channel part and clip the position, the left and right sides of this channel part, engages with above-mentioned noseplate portion respectively.

4, automobile underbody structure as claimed in claim 1 is characterized in that,

Described chassis, anterior and described chassis rear portion interconnects and forms by described chassis, have the pair of right and left side wall portion, connect the bottom wall portion of lower end of side wall portion of this pair of right and left and the pair of right and left flange part that extends from the upper end of this pair of right and left side wall portion, section roughly is the shape of falling the cap on the whole

The leading section at described chassis rear portion is formed with downwards the expansion section that enlarges with the side,

The rearward end of described chassis front portion is entrenched in the described expansion section at described chassis rear portion, and under this state, described chassis is anterior to be engaged with described chassis rear portion.

5, automobile underbody structure as claimed in claim 1 is characterized in that:

Described crossbeam comprises fore-and-aft direction the 1st crossbeam of midway location roughly that is arranged on described noseplate portion; And be arranged on the 1st crossbeam and described back and go up the 2nd crossbeam between the turn of bilge;

Described chassis tilts respectively with respect to described the 1st crossbeam and the 2nd crossbeam by overlooking observation.

6, automobile underbody structure as claimed in claim 5 is characterized in that:

Described each crossbeam, a pair of flange part place engages with the upper surface of described noseplate portion before and after it respectively,

Described each chassis engages with the bottom surface of described noseplate portion at the flange part place of its pair of right and left respectively,

Each flange part of each flange part of described each crossbeam and the chassis of described pair of right and left is being observed cross one another position by overlooking, and is engaged with 3 overlapping states with described noseplate portion.

7, as each described automobile underbody structure in the claim 1 ~ 6, it is characterized in that:

The front baffle of described pair of right and left extends along fore-and-aft direction in parallel to each other,

The front interval of the chassis of described pair of right and left is set at the rear end of the front baffle of described pair of right and left roughly the same at interval.

8, automobile underbody structure as claimed in claim 1 is characterized in that, also comprises:

Engage with described noseplate portion, and extend and the load crossbeam that intersects with described each chassis along the overall width direction; And

Be arranged on the below of described back base plate and the pair of right and left rear frame that extends along fore-and-aft direction;

Described load crossbeam connects the rearward end of described each chassis and the leading section of described rear frame respectively,

Described rear frame, its leading section is connected with the rearward end of described curb girder,

Described load crossbeam forms by overlooking observation and roughly is forwards the arch of protruding.

9, automobile underbody structure as claimed in claim 1 is characterized in that, also comprises:

Be arranged on the below of described back base plate, along the pair of right and left rear frame of fore-and-aft direction extension; And

The connecting frame that engages with the bottom surface of described noseplate portion;

Described rear frame, its leading section is connected with the rearward end of described curb girder,

Described connecting frame, the end is connected with the leading section of described rear frame thereafter, and its leading section is arranged on the basal surface position with the corresponding noseplate of the cross part of described chassis and crossbeam portion.

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