JP2023011827A - Vehicle lower structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit bending deformation of a cross member.

SOLUTION: A vehicle lower structure comprises: a pair of left and right side members 2 provided to side portions of a lower surface of a floor panel 1 in the vehicle width direction and extending in the vehicle length direction; a power source member 3 provided between the pair of left and right side members 2; and a cross member 4 extending in the vehicle width direction and connecting the pair of left and right side members 2 to each other. The cross member 4 comprises: a main portion 41 having a closed cross-sectional structure to which the power source member 3 is fixed; and flange portions 42 fixed to the side members 2. The side members 2 and the flange portions 42 are fixed via a bracket member 6. A closed cross section S1 is formed by combining the bracket member 6 and the cross member 4. The closed cross section S1 is arranged in a position which crosses a boundary region R between the main portion 41 and the flange portion 42 in the vehicle width direction. The bracket member 6 includes a cross member-side fixing portion 61 fixed to the cross member 4 at a position on an inner side in the vehicle width direction.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a vehicle undercarriage.

2. Description of the Related Art A vehicle such as an electric vehicle or a hybrid vehicle is equipped with a power source member such as a driving battery, and the power source member is provided in a lower portion of the vehicle, such as a vehicle body floor, for reasons of layout. Therefore, in electric vehicles, hybrid vehicles, etc., it is necessary to take measures to avoid damage to the power supply member due to the impact load, particularly in the event of a vehicle side collision.
Therefore, in conventional vehicles, by providing a ductile member in the flange portion that fixes the battery frame (cross member) that supports the battery to the under member (side member), when the impact load at the time of side collision is applied, In addition, there is a structure that suppresses damage from the flange portion to the bottom portion of the battery frame (see Patent Document 1, for example).

JP 2014-80117 A

However, the conventional vehicle lower structure described above is a structure that bends and deforms the battery frame from the flange to the bottom in the event of a side collision, so it is not possible to sufficiently distribute or absorb the load. There was a risk of increasing the amount of intrusion into the Therefore, the conventional vehicle lower structure has room for improvement as a structure for suppressing damage to the power supply member, which is an important component.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bracket member that is combined with a cross member to form a closed cross-sectional portion at a specific position, thereby reducing impact load in the event of a side collision. To provide a vehicle lower part structure capable of efficiently transmitting and dispersing to a cross member and suppressing bending deformation of the cross member.

In order to solve the above-described problems of the prior art, the present invention provides a pair of left and right side members, which are provided on the vehicle width direction side portions of the lower surface of the floor panel and extend in the vehicle front-rear direction, and between the left and right side members. and a cross member extending in the width direction of the vehicle and connecting the pair of left and right side members. In the vehicle lower structure having a flange portion fixed to a vehicle, the side member and the flange portion are fixed via a bracket member, and are closed by combining the bracket member and the cross member. A cross-sectional portion is formed, the closed cross-sectional portion is disposed at a position straddling a boundary region between the main body portion and the flange portion in the vehicle width direction, and the bracket member is attached to the cross member at a position on the vehicle width direction inner side. It has a fixed cross member side fixing part.

As described above, the vehicle lower portion structure according to the present invention includes a pair of left and right side members that are provided on the vehicle width direction side portions of the lower surface of the floor panel and extend in the vehicle front-rear direction, and a power source that is provided between the pair of left and right side members. and a cross member extending in the width direction of the vehicle and connecting the pair of left and right side members. The side member and the flange portion are fixed via a bracket member, and the bracket member and the cross member are combined to form a closed cross-sectional portion. The closed section portion is disposed at a position straddling a boundary region between the main body portion and the flange portion in the vehicle width direction, and the bracket member is fixed to the cross member at a vehicle width direction inner side position. has a part.
Therefore, in the vehicle lower part structure of the present invention, the bracket member combined with the cross member to form a closed cross-sectional portion at a specific position absorbs the impact load applied to the side member from the outside of the vehicle in the event of a side collision, thereby preventing the cross member from being damaged. This is important because bending deformation and breakage between the main body and the flange are suppressed, and the load in the vehicle width direction is efficiently transmitted from the side members to the cross member via the bracket member and distributed. It is possible to effectively protect the power supply member, which is a part, from the impact load in the event of a side collision.

1 is a perspective view showing the entirety of a floor panel, a side member, a cross member, and the like in a vehicle lower structure according to an embodiment of the invention from below the vehicle; FIG. It is a perspective view which expands and shows the Z section in FIG. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2; FIG. 3 is a cross-sectional perspective view taken along the line BB in FIG. 2; FIG. 3 is a sectional view taken along line CC in FIG. 2; 1 is a perspective view showing a positional relationship among a cross member, a bracket member, and a fixing auxiliary member in the vehicle lower portion structure according to the embodiment of the present invention; FIG. FIG. 2 is a top plan view of a bracket member in the vehicle lower portion structure according to the embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the illustrated embodiments.
In the drawings, the direction of arrow Fr indicates the front of the vehicle, and the direction of arrow I indicates the inside in the width direction of the vehicle. The arrow X direction indicates the vehicle width direction, and the arrow Y direction indicates the vehicle front-rear direction.

1 to 7 show a vehicle lower structure according to an embodiment of the invention. As shown in FIGS. 1 to 5, the vehicle lower structure of the present embodiment is provided on the vehicle width direction side portion of the lower surface of a floor panel 1 that extends in the vehicle width direction and the vehicle front-rear direction. a pair of side members 2; a power supply member (drive battery, battery pack, etc.) 3 provided between the pair of left and right side members 2 and mounted below the floor panel 1; The cross members 4 are positioned below the power source member 3 and spaced apart in the vehicle front-rear direction. note that,
A pair of left and right side sills 5 extending in the vehicle front-rear direction are provided outside the side member 2 in the vehicle width direction.
The cross member 4 of the present embodiment has a main body portion 41 with a closed cross-sectional structure to which the power supply member 3 is fixed by the fixing portion D, and a flange portion 42 fixed to the side member 2 . The body portion 41 is positioned in the middle portion of the cross member 4 in the width direction of the vehicle, and has a pair of upper and lower member bodies 41a and 41b that are vertically spaced apart from each other. The flange portion 42 is positioned at the outer end portion of the cross member 4 in the vehicle width direction, and is a pair of upper and lower member bodies 41a and 41b so as to close the opening end of the main body portion 41 on the outer side in the vehicle width direction when viewed from the rear of the vehicle. is joined to

In the vehicle lower portion structure of this embodiment, as shown in FIGS. 3 to 5, the side member 2 and the flange portion 42 of the cross member 4 are fixed via the bracket member 6. By being combined with the member 4, a closed cross-sectional portion S1 that enhances the rigidity around the fixed portion of the bracket member 6 is formed. Moreover, this closed cross section S1
It is arranged at a position straddling the boundary region R between the main body portion 41 and the flange portion 42 of the cross member 4 in the vehicle width direction. It is designed to be shifted. The bracket member 6 also has a cross member side fixing portion 61 fixed to the main body portion 41 of the cross member 4 at a position on the inside in the vehicle width direction. Furthermore, as shown in FIG. 5, an end closed cross-sectional portion formed by the body portion 41 and the flange portion 42 of the cross member 4 is located below the closed cross-sectional portion S1 positioned on the vehicle width direction outer side of the bracket member 6. S2 is provided, and the end closed cross-sectional portion S2 is connected to the closed cross-sectional portion of the main body portion 41 having a closed cross-sectional structure, and acts to transfer the load applied to the fixing portion between the side member 2 and the cross member 4 in the vehicle width direction. transmission is facilitated.

As shown in FIGS. 3 to 7, the bracket member 6 of the present embodiment is formed in a rectangular shape when viewed from the top of the vehicle. extending from the vehicle width direction inner end portion of the side fixing portion 62 to the cross member side fixing portion 61,
It has an inclined surface 63 that inclines downward toward the inside in the vehicle width direction. That is, the bracket member 6 is formed by processing a plate-like member so that the central portion bulges upward from the vehicle, leaving an inner portion 6a in the vehicle width direction and a front portion 6b and a rear portion 6c in the longitudinal direction of the vehicle. It is formed in a trapezoidal shape when viewed from the side of the vehicle, and spreads radially in three directions centering on the side member side fixing portion 62, and the lower surfaces of the inner portion 6a, the front portion 6b, and the rear portion 6c are joined to the cross member 4. configured to be The side member fixing portion 62 is provided with a through hole 65 through which a shaft portion of a fastening bolt (to be described later) is inserted.
As a result, the load from the side member 2 is smoothly transmitted to the cross member 4 via the side member side fixing portion 62 and the inclined surface 63 of the bracket member 6, thereby suppressing local concentration of the load. there is

7, the inclined surface 63 of the bracket member 6 of the present embodiment extends toward the cross member side fixing portion 61 from the corner portion 62a located inside the side member side fixing portion 62 in the vehicle width direction. It has a plurality of ridgelines 64 . These ridgelines 64 are provided on the front and rear portions of the inclined surface 63 at intervals in the vehicle front-rear direction. Such a ridge line 64 is the inclined surface 6
3, the load input in the vehicle width direction from the side member side fixing portion 62 of the bracket member 6 is efficiently transmitted along the ridgeline 64, and is transferred from the cross member side fixing portion 61 to the cross member 4 side. distributed to reduce local concentration of load.

On the other hand, as shown in FIGS. 2 and 3, the cross member 4 of the present embodiment has a curved portion 43 that curves inward in the vehicle width direction in the boundary region R between the main body portion 41 and the flange portion 42. ing. That is, the curved portion 43 is formed in a substantially horizontal S-shape that curves inward in the vehicle width direction from the flange portion 42 positioned above the cross member 4 toward the lower member body 41b of the main body portion 41 . , the peripheral portion of the curved portion 43 is joined to the lower member body 41 b of the main body portion 41 . The closed cross-sectional portion S1 on the side of the bracket member 6 is formed by the curved portion 43 having such a shape.
The change in cross-sectional area of the total closed cross-sectional area including the closed cross-sectional areas of the main body 41 of the cross member 4 is reduced, and a structure is obtained in which the area of the total closed cross-sectional area is maintained.
By the way, the curved portion 43 of the cross member 4 has rigidity against the load in the vertical direction of the vehicle. Therefore, the curved portion 43 is arranged at a position overlapping the inclined surface 63 of the bracket member 6 in the vehicle width direction. As a result, when the load concentrates on the portion where the curved portion 43 and the main body portion 41 are joined together and deformation occurs, the curved portion 43 is arranged within the range of the inclined surface 63 . The load is transmitted to the curved portion 43, and the load concentration on the curved portion 43 can be prevented.

As shown in FIGS. 3 to 5, the side member 2 of the present embodiment includes a planar lower surface 2a, and left and right side walls positioned inside and outside of the lower surface 2a in the vehicle width direction and extending upwardly of the vehicle. 2b
, 2c and has a substantially U-shaped cross section. Inside the side member 2, a cylindrical fixing member 7 for fixing the side member 2 and the cross member 4, and a reinforcement 21 for connecting the left and right side walls 2b and 2c of the side member 2 are provided. Therefore, the fixing member 7
is formed with a female thread that engages with the male thread of the shaft portion of the fastening bolt 8 that fastens the side member 2 and the cross member 4 together. Further, the reinforcement 21 is positioned above the lower surface 2a of the side member 2, and the attachment surface 21a is arranged with a gap from the lower surface 2a.
, and side surfaces 21b and 21c joined to the left and right side walls 2b and 2c of the side member 2. The mounting surface 21a is provided with a mounting hole 21d into which the upper portion of the fixing member 7 is inserted.
The lower surface 2a of the side member 2, the body portion 41 and the flange portion 42 of the cross member 4 are provided with shafts for the fastening bolts 8 corresponding to the through holes 65 of the bracket member 6 and the mounting holes 21d of the reinforcement 21. Insertion holes 2d, 41c, and 42a through which the parts are inserted are provided.
The fixing member 7 has a small-diameter upper portion 7a located at the upper end of the cylindrical body, a large-diameter lower portion 7b located at the lower end of the cylindrical body, and a diameter between the upper and lower portions 7a and 7c located between the upper and lower portions of the cylindrical body. The vertical length of the fixing member 7 is slightly larger than the interval between the lower surface 2a of the side member 2 and the attachment surface 21a of the reinforcement 21. As shown in FIG. Fixing member 7
The upper portion 7a of is protruded above the mounting surface 21a through the mounting hole 21d, and is joined to the reinforcement 21 with the intermediate portion 7c in contact with the lower surface of the mounting surface 21a. Fixing member 7
is joined onto the lower surface 2a of the side member 2. As shown in FIG.
As a result, the load in the vehicle width direction input to the right side wall 2c of the side member 2 is transmitted to the cross member 4 via the reinforcement 21 and the fixing member 7, thereby facilitating the transmission and distribution of the load. It has a structure that

Further, between the bracket member 6 and the flange portion 42 of the cross member 4 of this embodiment, as shown in FIGS. A fixed support member 9 of the shape is provided. Therefore, the auxiliary fixing member 9 is fixed to the side member side fixing portion 62 of the bracket member 6 and the upper member body 41 of the main body portion 41 of the cross member 4 .
a, and the upper and lower surfaces of the cylindrical body have a vertical length that allows contact with the side member side fixing portion 62 and the upper member body 41a. In addition, the auxiliary fixing member 9 has an inner diameter through which the fastening bolt 8 can be inserted. Moreover, the fixing member 7 and the fixing auxiliary member 9
are fastened by fastening bolts 8 and have a structure that can utilize the rigidity of the fastening bolts 8 in the vehicle width direction.
As a result, the load input from the side member 2 is transmitted to the cross member 4 via the auxiliary fixing member 9, further promoting the distribution of the load.

As described above, in the vehicle lower portion structure according to the embodiment of the present invention, the pair of left and right side members 2 provided on the vehicle width direction side portions of the lower surface of the floor panel 1 and extending in the vehicle front-rear direction, and the pair of left and right side members 2 A power supply member 3 provided therebetween and a cross member 4 extending in the vehicle width direction and connecting the pair of left and right side members 2 are provided. The cross member 4 has a body portion 41 having a closed cross-section structure to which the power supply member 3 is fixed, and a flange portion 42 fixed to the side member 2 . The side member 2 and the flange portion 42 are fixed via the bracket member 6, and the bracket member 6 and the cross member 4 are combined to form a closed cross-sectional portion S1. It is arranged at a position straddling a boundary region R between the main body portion 41 and the flange portion 42 in the vehicle width direction. The bracket member 6 also has a cross member side fixing portion 61 fixed to the cross member 4 at a position on the inner side in the vehicle width direction.
That is, in the vehicle lower portion structure of the present embodiment, since the bracket member 6 that is combined with the cross member 4 to form the closed cross-sectional portion S1 at a specific position is provided, the side member 2 can be damaged from the outside of the vehicle in the event of a side collision. It is possible to absorb the applied impact load, and it is possible to suppress bending deformation and breakage between the body portion 41 and the flange portion 42 of the cross member 4 against the load from the outside of the vehicle. In addition, in the vehicle lower portion structure of the present embodiment, the load in the vehicle width direction is efficiently transmitted from the side member 2 to the cross member 4 via the bracket member 6 and distributed. It is possible to effectively protect the power supply member 3 from the impact load at the time of side collision.

In the vehicle lower portion structure of the present embodiment, the bracket member 6 includes a side member side fixing portion 62 fixed to the lower surface 2a of the side member 2, and a cross member extending from the vehicle width direction inner end portion of the side member side fixing portion 62. It has an inclined surface 63 extending to the side fixing portion 61 and inclined downward inward in the vehicle width direction.
Therefore, according to the vehicle lower portion structure of the present embodiment, the load from the side member 2 is transferred to the cross member 4 through the side member side fixing portion 62 and the inclined surface 63 of the bracket member 6 in the event of a side collision.
Since the load is transmitted to the side, local concentration of the load can be suppressed, and bending deformation of the cross member 4 can be suppressed. Thereby, the effect of protecting the power supply member 3 against the impact load at the time of side collision can be further enhanced.

In addition, in the vehicle lower portion structure of the present embodiment, the inclined surface 63
2 toward the cross-member-side fixing portion 61, and the ridgelines 64 are provided on the front and rear portions of the inclined surface 63 with a space therebetween in the vehicle front-rear direction. Therefore, according to the vehicle lower portion structure of the present embodiment, in the event of a side collision, the load input in the vehicle width direction from the side member side fixing portion 62 of the bracket member 6 is transmitted along the ridge line 64 and is fixed to the cross member side. Since the load is distributed toward the cross member 4 from the portion 61, the local concentration of the load can be further suppressed.

Further, in the vehicle lower portion structure of the present embodiment, the cross member 4 has a curved portion 43 that curves inward in the vehicle width direction in the boundary region R between the main body portion 41 and the flange portion 42 . The curved portion 43 is arranged at a position overlapping the inclined surface 63 in the vehicle width direction. Therefore, in the vehicle lower portion structure of the present embodiment, it is possible to reduce the change in the cross-sectional area of the total closed cross-sectional portion including the closed cross-sectional portion S1 formed by the bracket member 6 and the closed cross-sectional portion of the main body portion 41 of the cross member 4. Since it becomes possible, it is possible to prevent the load from being concentrated on the curved portion 43 .

In the vehicle lower portion structure of this embodiment, the side member 2 is formed to have a substantially U-shaped cross section. Reinforcement 21 connecting left and right side walls 2b and 2c of side member 2
is provided. An upper portion 7 a of the fixing member 7 is joined to the reinforcement 21 , and a lower portion 7 b of the fixing member 7 is joined to the lower surface 2 a of the side member 2 .
Therefore, in the vehicle lower portion structure of the present embodiment, when a load is input to the lower surface 2a of the side member 2 and the reinforcement 21 from the vehicle width direction, the fixing member 7 is moved between the reinforcement 21 and the side member 2. Since the joint portion receives the load in the vehicle width direction, the rigidity of the fixing member 7 in the vehicle width direction can be utilized. Moreover, in the vehicle lower portion structure of the present embodiment, the load in the vehicle width direction input to the right side wall 2c on the vehicle width direction outer side of the side member 2 is transmitted to the cross member 4 via the reinforcement 21 and the fixing member 7. Therefore, the load transmission in the width direction of the vehicle can be promoted, and the impact load at the time of side collision can be smoothly distributed to the cross member 4 and the like.

In addition, in the vehicle lower portion structure of the present embodiment, the fixation assisting member 9 is provided between the bracket member 6 and the flange portion 42 to assist the fixation of the side member 2 and the cross member 4. 2 can be smoothly transmitted to the cross member 4 via the fixing auxiliary member 9, and the load dispersion effect can be further enhanced.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes are possible based on the technical idea of the present invention.

1 floor panel 2 side member 2a lower surface 2b, 2c side wall 2d insertion hole 3 power supply member 4 cross member 6 bracket member 7 fixing member 7a upper portion 7b lower portion 7c intermediate portion 8 fastening bolt 9 fixing auxiliary member 21 reinforcement 21a mounting surface 21b, 21c side surface 21d attachment hole 41 cross member body portion 41a upper member body 41b lower member body 41c insertion hole 42 cross member flange portion 42a insertion hole 43 curved portion 61 cross member side fixing portion 62 side member side fixing portion 63 inclined surface 64 Ridgeline 65 Through hole R Boundary region between body portion and flange portion of cross member S1 Closed section portion

The present invention has been made in view of such circumstances, and its object is to efficiently transmit and distribute the impact load in the event of a side collision to the cross member, thereby suppressing bending deformation of the cross member. To provide a vehicle lower structure that is compact.

In order to solve the above-described problems of the prior art, the present invention provides a pair of left and right side members, which are provided on the vehicle width direction side portions of the lower surface of the floor panel and extend in the vehicle front-rear direction, and between the left and right side members. and a cross member extending in the width direction of the vehicle and connecting the pair of left and right side members. The cross member is fixed to the side member as well as to the power source member. A vehicle lower structure, wherein the side member and the cross member are fixed via a bracket member, and a plurality of the cross members are fixed to the power supply member .

In the vehicle underbody structure of the present invention, the load in the vehicle width direction is efficiently transmitted from the side member to the cross member via the bracket member and distributed. It can effectively protect against impact loads.

Claims (6)

a pair of left and right side members provided on the vehicle width direction sides of the lower surface of the floor panel and extending in the vehicle front-rear direction; a power supply member provided between the left and right side members; a cross member connecting the side members,
In the vehicle lower portion structure, wherein the cross member has a main body portion having a closed cross-section structure to which the power source member is fixed, and a flange portion fixed to the side member,
The side member and the flange portion are fixed via a bracket member, and a closed cross-sectional portion is formed by combining the bracket member and the cross member,
The closed cross-section portion is arranged at a position straddling a boundary region between the body portion and the flange portion in the vehicle width direction,
The vehicle lower portion structure, wherein the bracket member has a cross member side fixing portion that is fixed to the cross member at a position on the inside in the vehicle width direction. The bracket member includes a side member side fixing portion fixed to the lower surface of the side member, a vehicle width direction inner end portion of the side member side fixing portion extending to the cross member side fixing portion, and extending inward in the vehicle width direction. 2. The vehicle lower structure according to claim 1, further comprising an inclined surface that slopes downward. The inclined surface has a ridgeline extending from the side member side fixed portion toward the cross member side fixed portion. The vehicle lower structure according to claim 2, characterized in that: The cross member has a curved portion that curves inward in the vehicle width direction in a boundary region between the body portion and the flange portion, and the curved portion is arranged at a position overlapping the inclined surface in the vehicle width direction. 4. The vehicle lower structure according to claim 2 or 3, characterized in that the lower structure is provided. The side member is formed to have a substantially U-shaped cross section, and inside the side member are a fixing member for fixing the side member and the cross member, and a reinforcement for connecting the left and right side walls of the side member. An upper portion of the fixing member is joined to the reinforcement, and a lower portion of the fixing member is joined to the lower surface of the side member. vehicle undercarriage. 6. The apparatus according to any one of claims 1 to 5, wherein a fixation assisting member is provided between the bracket member and the flange portion to assist fixation of the side member and the cross member. Vehicle undercarriage.

Images