JP7175809B2 - Ladder frame reinforcement structure - Google Patents

Description

The present disclosure relates to a ladder frame reinforcement structure that reinforces side rails of a ladder frame.

As a method of reinforcing a side rail having a C-shaped cross section of a ladder frame, as shown in FIG. there is

JP-A-10-81259 JP 2013-166401 A

However, with the reinforcement method described above, it is difficult to increase the rigidity against input in the torsional direction. That is, if the thickness of the reinforcing member 30 is set thick in order to obtain the necessary torsional rigidity, the weight of the reinforcing member 30 increases excessively. (distortion, torsion) can easily cause a decrease in rigidity.

Accordingly, the present disclosure was created in view of such circumstances, and an object thereof is to provide a ladder frame reinforcement structure capable of improving the torsional rigidity of side rails while suppressing an increase in weight.

According to one aspect of the present disclosure,
a pair of side rails spaced apart on the left and right;
a cross member that spans between the side rails;
and a reinforcing member provided on the side rail,
The side rail includes a web portion extending in the vertical direction, an upper flange portion extending in the horizontal direction from the upper end of the web portion, and a lower flange portion extending from the lower end of the web portion in the same direction as the upper flange portion. ,
The reinforcing member has a vertical portion extending vertically along the web portion, a horizontal portion extending horizontally along at least one of the upper flange portion and the lower flange portion, and a portion between the vertical portion and the horizontal portion. and an inclined portion formed in and extending in an oblique direction,
The inclined portion includes a large inclined portion formed at a position separated from the cross member in the front-rear direction, and a large inclined portion formed at a position in the front-rear direction where the cross member is located, and formed with a shorter length in the inclined direction than the large inclined portion. and a gradual change portion formed between the large and small inclined portions for continuously reducing the length in the direction of inclination from the large inclined portion to the small inclined portion. There is provided a ladder frame reinforcement structure characterized by:

Further, according to one aspect of the present disclosure,
a pair of side rails spaced apart on the left and right;
a cross member that spans between the side rails;
and a reinforcing member provided on the side rail,
The side rail includes a web portion extending in the vertical direction, an upper flange portion extending in the horizontal direction from the upper end of the web portion, and a lower flange portion extending in the same direction as the upper flange portion from the lower end of the web portion. ,
The reinforcing member includes a vertical portion extending vertically along the web portion, an upper horizontal portion extending horizontally along the upper flange portion, and a lower horizontal portion extending horizontally along the lower flange portion. an upper inclined portion formed between the vertical portion and the upper horizontal portion and extending in an oblique direction; and a lower inclined portion formed between the vertical portion and the lower horizontal portion and extending in an oblique direction;
At least one of the upper inclined portion and the lower inclined portion includes a large inclined portion formed at a position separated from the cross member, and a large inclined portion formed at a position in the front-rear direction where the cross member is located and inclined from the large inclined portion. a small inclined portion formed to have a short length in the direction; and a small inclined portion formed between the large inclined portion and the small inclined portion, the length of the inclined direction being continuously reduced from the large inclined portion toward the small inclined portion. A rudder frame reinforcing structure is provided, comprising: a gradually changing portion;

Also, the vertical part may be formed by being divided into upper and lower parts.

Preferably, the cross member is fastened with the reinforcing member sandwiched between at least one of the upper flange portion and the lower flange portion facing the small inclined portion.

Further, the cross member may be fastened with the reinforcing member sandwiched between the web portions facing the small inclined portion.

Further, a longitudinal bead extending in the vertical direction may be formed on the vertical portion.

According to the above aspect, it is possible to improve the torsional rigidity of the side rail while suppressing an increase in weight.

1 is a schematic explanatory diagram of a ladder frame according to an embodiment of the present disclosure; FIG. It is an A section expansion perspective view of a ladder frame. FIG. 3 is a cross-sectional view taken along line BB of FIG. 2; 3 is a cross-sectional view taken along line CC of FIG. 2; FIG. It is a principal part expansion perspective view of the ladder frame which shows a modification. FIG. 11 is a perspective view of a side rail and a reinforcing member showing another embodiment; FIG. 11 is a perspective view of a side rail and a reinforcing member showing another embodiment; 1 is a perspective view of a side rail reinforced by a conventional reinforcement method; FIG.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the front, rear, left, right, up and down directions in the embodiments described later refer to the directions of a vehicle in which a ladder frame described later is employed. However, each direction in this embodiment is used for convenience of explanation, and represents relative positional relationships between members described later.

FIG. 1 is a schematic explanatory diagram of a ladder frame 1 according to this embodiment as viewed from above. FIG. 2 is an enlarged perspective view of the A portion of the ladder frame 1 as seen obliquely from the front.

As shown in FIGS. 1 and 2, the ladder frame 1 includes a pair of side rails 2 that are spaced apart from each other in the left and right direction, a cross member 3 that spans between the side rails 2, and the side rails 2. and a reinforcing member 4 provided.

The side rails 2 are made of steel or the like elongated in the front-rear direction, and have a C-shaped cross section. The side rail 2 is formed by bending a steel plate or the like into a C shape. The side rail 2 is arranged with the C-shaped opening directed inward in the vehicle width direction. The side rail 2 includes a web portion 5 extending in the vertical direction, an upper flange portion 6 extending horizontally from the upper end of the web portion 5, and a lower flange portion 7 extending from the lower end of the web portion 5 in the same direction as the upper flange portion 6. and The upper flange portion 6 and the lower flange portion 7 are set to have the same length in the left-right direction (vehicle width direction). Moreover, the vertical length of the web portion 5 is set longer than the horizontal length of the upper flange portion 6 (or the lower flange portion 7).

As shown in FIGS. 2, 3 and 4, the reinforcing member 4 is made of a steel material or the like elongated in the front-rear direction, and is provided in the side rail 2, that is, the web portion 5 of the side rail 2 and the upper flange portion. 6 and the lower flange portion 7 . The reinforcing member 4 includes a vertical portion 8 extending vertically along the inner surface of the web portion 5 , an upper horizontal portion 9 extending horizontally along the inner surface of the upper flange portion 6 , and along the inner surface of the lower flange portion 7 . an upper inclined portion 11 formed between the vertical portion 8 and the upper horizontal portion 9 and extending obliquely upward from the vertical portion 8; and a lower inclined portion 12 extending obliquely downward from the vertical portion 8 .

The vertical portion 8 is arranged in the vertical central portion of the web portion 5 . That is, the upper end 8a of the vertical portion 8 is positioned below the upper end 5a of the web portion 5, and the lower end 8b of the vertical portion 8 is positioned above the lower end 5b of the web portion 5. As shown in FIG.

The base end 9a of the upper horizontal portion 9 (the end connected to the upper inclined portion 11) is positioned inward in the vehicle width direction from the base end 6a of the upper flange portion 6 (the end connected to the web portion 5). As a result, a triangular upper closed cross section 13 surrounded by the web portion 5 , the upper flange portion 6 and the upper inclined portion 11 is formed at the upper corner portion of the side rail 2 .

A base end 10a of the lower horizontal portion 10 is positioned inward of the base end 7a of the lower flange portion 7 in the vehicle width direction. As a result, a triangular lower closed section 14 surrounded by the web portion 5 , the lower flange portion 7 and the lower inclined portion 12 is formed at the lower corner portion of the side rail 2 .

The upper closed cross-section portion 13 and the lower closed cross-section portion 14 are generally formed in the shape of an isosceles right triangle.

Further, the tip 9b of the upper horizontal portion 9 and the tip 6b of the upper flange portion 6 are aligned in the horizontal direction. The tip 9b of the upper horizontal portion 9 is joined to the tip 6b of the upper flange portion 6 by edge joint welding. The tip 10b of the lower horizontal portion 10 is aligned with the tip 7b of the lower flange portion 7 in the left-right direction. A tip 10b of the lower horizontal portion 10 is joined to a tip 7b of the lower flange portion 7 by an edge weld joint. Note that the joining of the side rail 2 and the reinforcing member 4 is not limited to the above. For example, if the side rails 2 and the reinforcing member 4 are relatively small in thickness, the side rails 2 and the reinforcing member 4 may be joined by spot welding or the like. In this case, the vertical portion 8 and the web portion 5 may be joined by spot welding or the like.

Moreover, in the present embodiment, the side rails 2 and the reinforcing members 4 are formed vertically symmetrically. That is, the upper inclined portion 11 and the lower inclined portion 12 of the reinforcing member 4 are also formed vertically symmetrically. Therefore, only the lower sloped portion 12 will be described below, and the description of the upper sloped portion 11 will be omitted.

The lower inclined portion 12 is arranged at different positions in the longitudinal direction. A lower small slope portion 16 having a short length from an end 16 a to a tip 16 b , and a lower gradually changing portion 17 formed between the lower large slope portion 15 and the lower small slope portion 16 .

The lower large inclined portion 15, the lower small inclined portion 16, and the lower gradually changing portion 17 are inclined at an angle θ of approximately 45° with respect to the horizontal plane. The angle θ of the lower large slope portion 15 and the lower small slope portion 16 is not limited to this. For example, the angle θ of the lower large slope portion 15 and the lower small slope portion 16 may be in the range of 30° to 60° (30°≦θ≦60°).

The lower large inclined portion 15 is formed at a position separated from the cross member 3 in the front-rear direction. A base end 15a of the lower large inclined portion 15 is positioned adjacent to the vicinity of the center of the web portion 5 in the vertical direction. Further, the tip 15b of the lower large inclined portion 15 is positioned adjacent to the tip 7b of the lower flange portion 7 in the left-right direction. Accordingly, the length of the lower large inclined portion 15 in the inclined direction (the length from the proximal end 15a to the distal end 15b) is set long, and the torsional rigidity of the side rail 2 is relatively greatly improved.

The lower small inclined portion 16 is formed at a position in the front-rear direction where the cross member 3 is located. In addition, a lower small inclined portion 16 is formed at the end portion 4a of the reinforcing member 4 in the front-rear direction. A base end 16a of the lower small inclined portion 16 is positioned adjacent to the vicinity of the lower end of the web portion 5 in the vertical direction. Further, the tip 16b of the lower small inclined portion 16 is positioned adjacent to the vicinity of the base end 7a of the lower flange portion 7 in the left-right direction. As a result, the length of the lower small inclined portion 16 in the inclined direction (the length from the proximal end 16a to the distal end 16b) is set shorter than that of the lower large inclined portion 15, thereby slightly improving the torsional rigidity of the side rail 2. . Further, interference between the lower small inclined portion 16 and the cross member 3 is prevented or suppressed.

The lower gradually changing portion 17 moves the position of the base end 17a downward and moves the position of the tip 17b outward in the vehicle width direction as it approaches the lower small slope portion 16 from the lower large slope portion 15 . As a result, the length of the lower gradually changing portion 17 in the direction of inclination (the length from the proximal end 17a to the distal end 17b) is continuously reduced. That is, the lower gradually changing portion 17 is formed in a flat plate shape that is inclined in the left-right direction and also inclined in the front-rear direction. Thereby, the lower large slope portion 15 and the lower small slope portion 16 are smoothly connected via the lower gradually changing portion 17 . In addition, the cross-sectional shape of the lower closed cross-section portion 14 formed by the web portion 5, the lower flange portion 7, and the lower gradually changing portion 17 approaches the lower small inclination portion 16 side from the lower large inclination portion 15 side. It is reduced in size while maintaining a similar shape. As a result, the rigidity of the side rail 2 reinforced by the reinforcing member 4 gradually decreases between the lower large inclined portion 15 and the lower small inclined portion 16, and a portion where the rigidity suddenly changes is not formed. Therefore, it is possible to suppress the occurrence of stress concentration between the lower large slope portion 15 and the lower small slope portion 16 .

In addition, notch portions 24 are formed in the vertical portions 8 positioned at the front and rear ends of the reinforcing member 4 to weaken the reinforcement. The cutout portion 24 is formed in a V shape that widens toward the end 4a of the reinforcing member 4 in the front-rear direction.

Note that the upper inclined portion 11 and the lower inclined portion 12 may be formed asymmetrically in the vertical direction. For example, when the strength required for the upper side of the side rail 2 is smaller than the rigidity required for the lower side, the upper inclined portion 11 may be set smaller than the lower inclined portion 12 . Either one of the upper inclined portion 11 and the lower inclined portion 12 may be omitted. In this case, the reinforcing member 4 includes a vertical portion 8, one of the upper horizontal portion 9 and the lower horizontal portion 10, and an upper inclined portion 11 or a lower inclined portion formed between the one horizontal portion and the vertical portion 8. 12 should be provided. In this case, of course, the reinforcing member 4 may have the other horizontal portion.

The cross member 3 is made of steel or the like elongated in the left-right direction, and has a C-shaped cross section. The cross member 3 includes a web portion 18 extending in the vertical direction, an upper flange portion 19 extending horizontally from the upper end of the web portion 18, and a lower flange portion 20 extending from the lower end of the web portion 18 in the same direction as the upper flange portion 19. and The flange portions 19 and 20 of the cross member 3 are fastened to the flange portions 6 and 7 of the side rail 2 with the reinforcing member 4 interposed therebetween. This fastening is made using bolts 21 and nuts 22 . Note that other fasteners such as rivets (not shown) may be used to fasten the cross member 3 and the side rails 2 .

Next, the operation of this embodiment will be described.

When a vehicle (not shown) runs on a rough road or the like and a torsional force about an axis extending in the longitudinal direction acts on the side rail 2 of the ladder frame 1, the side is slightly deformed by the force. The reinforcing member 4 receives a force in the vertical direction due to the flange portions 6 and 7 of the rail 2 . At this time, in a conventional reinforcing structure using a reinforcing member 30 (see FIG. 8) having a shape along the inner surface or outer surface of the side rail 2, the strength of the corner 31 tends to be insufficient, and the side rail 2 can be strengthened while suppressing an increase in weight. It was difficult to suppress the deformation.

On the other hand, in the reinforcing structure according to the present embodiment, the reinforcing member 4 is formed with the inclined portions 11 and 12 . Therefore, the closed cross-sectional portions 13 and 14 can be formed at the corners 2a of the side rails 2, and the corners 2a can be efficiently reinforced. That is, since the reinforcing member 4 has the inclined portions 11 and 12, the area of the reinforcing member 4 when deployed can be made smaller than that of the conventional structure, and the corner portion 2a of the side rail 2 can be reinforced more firmly. Reinforcement of the corners 2a by the closed cross-section structure improves the torsional rigidity of the side rails 2 and suppresses deformation of the side rails 2. As shown in FIG.

Furthermore, in the reinforcing structure according to the present embodiment, the reinforcing member 4 is formed with the large inclined portion 15 , the small inclined portion 16 and the gradually changing portion 17 . The small inclined portion 16 is formed at a position in the front-rear direction where the cross member 3 is located. Therefore, the inclined portions 11 and 12 can escape from the cross member 3 attached to the side rail 2 . In particular, the side rails 2 at the longitudinal position where the cross member 3 is located are reinforced by the cross member 3 . Therefore, even if the closed cross-sectional portions 13 and 14 at such positions are formed small, the side rails 2 can be sufficiently reinforced.

On the other hand, the side rails 2 at positions in the longitudinal direction where the cross members 3 are located may not need reinforcement by the reinforcing members 4 locally. However, if the reinforcing member 4 at such a position is omitted, the reinforcing member 4 becomes discontinuous in the front-rear direction. In this case, stress concentration may occur in the side rail 2 at the position where the reinforcing member 4 is interrupted. However, in the reinforcing structure according to the present embodiment, the inclined portions 11 and 12 (small inclined portions 16) are also arranged in the front and rear positions of the cross member 3 so that the inclined portions 11 and 12 are arranged in front of and behind the cross member 3. make it continuous. Therefore, stress concentration due to discontinuity of the reinforcing member 4 can be suppressed.

Also, the gradually changing portion 17 is formed between the large slope portion 15 and the small slope portion 16 . Therefore, the shapes of the inclined portions 11 and 12 between the large inclined portion 15 and the small inclined portion 16 can be continuously and gradually changed. As a result, the occurrence of stress concentration due to discontinuity in the shape of the reinforcing member 4 can be suppressed. Also, it is possible to suppress a reduction in the rigidity of the side rails 2 due to warping.

In addition, a lower small inclined portion 16 and a notch portion 24 are formed at the end portion 4a of the reinforcing member 4 in the front-rear direction. As a result, the change in rigidity of the side rail 2 at the boundary between the portion where the reinforcing member 4 is provided and the portion where the reinforcing member 4 is not provided can be kept small.

Although the embodiments of the present disclosure have been described above in detail, the present disclosure is also capable of other embodiments as follows.

(1) Although the cross member 3 is fastened to the flange portion of the side rail 2, it is not limited to this. As shown in FIG. 5, the cross member 3 may be fastened to the web portion 5 of the side rail 2 with the reinforcing member 4 interposed therebetween.

(2) As shown in FIG. 6, the vertical portion 8 may be divided into upper and lower parts. In this case, the upper vertical portion 8 and the lower vertical portion 8 may be separated vertically or may be in contact with each other.

(3) As shown in FIG. 7, the vertical portion 8 may be formed with a vertical bead 23 extending vertically. In this case, the vertical bead 23 is preferably formed so as to swell in a direction away from the web portion 5 (inward in the vehicle width direction).

Further, when the reinforcing member 4 includes the upper inclined portion 11 and the lower inclined portion 12, the upper end of the vertical bead 23 is connected to the upper inclined portion 11, and the lower end of the vertical bead 23 is connected to the lower inclined portion 12. good.

Further, when the reinforcing member 4 has only one of the upper inclined portion 11 and the lower inclined portion 12, the vertical bead 23 is connected to one inclined portion and to the horizontal portion on the side without the inclined portion. should be. Also, if the reinforcing member 4 does not have the lower inclined portion 12 and the lower horizontal portion 10 , the lower end of the vertical bead 23 is preferably brought into contact with the lower flange portion 7 of the side rail 2 . If the reinforcing member 4 does not have the upper inclined portion 11 and the upper horizontal portion 9 , the upper end of the vertical bead 23 is preferably brought into contact with the upper flange portion 6 of the side rail 2 .

The configurations of the respective embodiments described above can be partially or wholly combined as long as there is no contradiction. Embodiments of the present disclosure are not limited to the above-described embodiments, and include all modifications, applications, and equivalents encompassed by the concept of the present disclosure defined by the claims. Accordingly, the present disclosure should not be construed in a restrictive manner, and can be applied to any other technology that falls within the spirit of the present disclosure.

1 ladder frame 2 side rail 3 cross member 4 reinforcing member 5 web portion 6 upper flange portion 7 lower flange portion 8 vertical portion 9 upper horizontal portion (horizontal portion)
10 lower horizontal part (horizontal part)
11 upper inclined portion (inclined portion)
12 lower slope (slope)
15 lower large slope (large slope)
16 Lower small slope (small slope)
17 lower gradual change part ( gradual change part)
23 Vertical bead

Claims (6)

a pair of side rails spaced apart on the left and right;
a cross member that spans between the side rails;
and a reinforcing member provided on the side rail,
The side rail includes a web portion extending in the vertical direction, an upper flange portion extending in the horizontal direction from the upper end of the web portion, and a lower flange portion extending from the lower end of the web portion in the same direction as the upper flange portion. ,
The reinforcing member has a vertical portion extending vertically along the web portion, a horizontal portion extending horizontally along at least one of the upper flange portion and the lower flange portion, and a portion between the vertical portion and the horizontal portion. and an inclined portion formed in and extending in an oblique direction,
The inclined portion includes a large inclined portion formed at a position separated from the cross member in the front-rear direction, and a large inclined portion formed at a position in the front-rear direction where the cross member is located, and formed with a shorter length in the inclined direction than the large inclined portion. and a gradual change portion formed between the large and small inclined portions for continuously reducing the length in the direction of inclination from the large inclined portion to the small inclined portion. A ladder frame reinforcement structure characterized by: a pair of side rails spaced apart on the left and right;
a cross member that spans between the side rails;
and a reinforcing member provided on the side rail,
The side rail includes a web portion extending in the vertical direction, an upper flange portion extending in the horizontal direction from the upper end of the web portion, and a lower flange portion extending in the same direction as the upper flange portion from the lower end of the web portion. ,
The reinforcing member includes a vertical portion extending vertically along the web portion, an upper horizontal portion extending horizontally along the upper flange portion, and a lower horizontal portion extending horizontally along the lower flange portion. an upper inclined portion formed between the vertical portion and the upper horizontal portion and extending in an oblique direction; and a lower inclined portion formed between the vertical portion and the lower horizontal portion and extending in an oblique direction;
At least one of the upper inclined portion and the lower inclined portion includes a large inclined portion formed at a position separated from the cross member, and a large inclined portion formed at a position in the front-rear direction where the cross member is located and inclined from the large inclined portion. a small inclined portion formed to have a short length in the direction; and a small inclined portion formed between the large inclined portion and the small inclined portion, the length of the inclined direction of which is continuously reduced from the large inclined portion toward the small inclined portion. A rudder frame reinforcement structure, comprising: a gradually changing portion. 3. The ladder frame reinforcement structure according to claim 2, wherein the vertical portion is formed by dividing into upper and lower parts. The ladder frame according to any one of claims 1 to 3, wherein the cross member is fastened to at least one of the upper flange portion and the lower flange portion facing the small inclined portion with the reinforcing member sandwiched therebetween. reinforced structure. The ladder frame reinforcing structure according to any one of claims 1 to 3, wherein the cross member is fastened with the reinforcing member sandwiched between the web portion facing the small inclined portion. The ladder frame reinforcing structure according to any one of claims 1 to 5, wherein a vertical bead extending vertically is formed in the vertical portion.

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