JP2650527B2 - Car body strength member structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a strength member of a vehicle body, and more particularly to a structure of a strength member such as a front side member or a rear side member disposed in the front-rear direction of a vehicle body.

[0002]

2. Description of the Related Art FIG. 13 shows a vehicle body skeleton structure of an automobile. The vehicle body skeleton includes a side member SM and a side sill SS which are strength members in a vehicle longitudinal direction, and a plurality of cross members which are strength members in a vehicle width direction. The CM is joined to form a skeleton base, and the front pillar AP, the center pillar BP, and the rear pillar CP are erected on the skeleton base as strength members in the vertical direction of the vehicle body.

As the above-mentioned strength member in the longitudinal direction of the vehicle body, for example, a side member SM is known which is extruded into a rectangular closed cross section using an aluminum light alloy material as shown in FIG. 64-67482). The side member SM is provided with a plurality of welding beads 2 at appropriate intervals in the longitudinal direction on the peripheral wall at the end of the member main body 1, and has a knotted shape due to an annealing effect at the time of forming the welding beads 2. A rigid portion is formed, and when a collision input acts in the axial direction, the member main body 1 can be easily buckled and deformed by the low rigidity portion.

[0004] In addition, as shown in FIG. 15, a member body 1 extruded into a rectangular closed cross section by using an aluminum light alloy material in the same manner as described above, and a vertical section dividing the closed cross section into a plurality of sections. The rib 3 and the lateral rib 4 are integrally formed in the longitudinal direction,
It is also conceivable that the member main body 1 is formed in a lattice-like closed cross section.

[0005]

When a collision input acts on the side member SM in the axial direction at the time of a vehicle collision, a plurality of longitudinal members are formed on the peripheral wall at the end of the member main body 1 in the one shown in FIG. Since the weld bead 2 is formed and buckling deformation is likely to occur from these weld bead 2 portions as a starting point, the initial reaction force load Pc ₁ can be kept relatively small as shown by the line a in FIG. On the other hand, the average reaction force load Pm ₁ generated after the start of buckling is also reduced, and the amount of collision energy absorption is reduced.

Also, in the structure shown in FIG. 15, the closed cross section of the member main body 1 is formed in a lattice shape by the vertical ribs 3 and the horizontal ribs 4 so that the average is obtained as shown by the line b in FIG. demagnetizing force load Pm half _{of 2} can be increased collision energy absorption amount is increased, the impact force applied on the body initial resistance load Pc ₂ is increased becomes high.

Therefore, the present invention can reduce the initial reaction force load at the time of a collision and increase the average reaction force load after the start of buckling to secure a desired collision energy absorption amount. An object of the present invention is to provide an automobile body strength member structure.

[0008]

According to the present invention, there is provided a structure in which a rib which extrudes a closed cross section and is disposed in the longitudinal direction of a vehicle body has ribs for dividing the closed cross section into a plurality of pieces integrally formed in a longitudinal direction. An inclined portion is formed at an end of the rib from a connection point with the peripheral portion of the member main body toward the inside of the member main body.

[0009]

When a collision input acts on the end of the member body in the axial direction at the time of collision of the vehicle, a rib is formed at the end face of the member body from the connection point with the peripheral edge of the member body toward the inside of the member body. Because the rib cross section is extremely small, it is easy to buckle and deform in the axial direction.
The initial reaction force load can be kept small. Since the rib cross-sectional area gradually increases as the buckling progresses, the original reinforcing effect of the rib is obtained, the average reaction load is increased, and the collision energy absorption amount is increased.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail by giving the same reference numerals to the same parts as those of the above-mentioned conventional structure, taking side members as an example.

In FIGS. 1 and 2, reference numeral 1 denotes a side member SM extruded from an aluminum light alloy material into a rectangular closed cross section.
A vertical rib 3 and a horizontal rib 4 that divide the closed cross section into a plurality are integrally formed in the longitudinal direction inside the member main body 1. At the ends of the vertical ribs 3 and the horizontal ribs 4, inclined portions 3 a, 4 a extending from the connection point with the peripheral edge of the member main body 1 toward the inside of the member main body 1 are formed.
In this embodiment, the inclined portions 3a and 4a are formed in an arc shape with the intersection of the vertical ribs 3 and the horizontal ribs 4 as the deepest portion, and the ribs are cut from the end face side of the member body 1 toward the inside. The area is gradually increased from zero so that buckling deformation is easily caused when a collision input acts on the end portion in the axial direction.

Here, the length of the long side of the member body 1 is L
a, the length of the inclined portions 3a, 4a from the end surface of the member main body 1 to the deepest portion is defined as Lb. Considering the change in the initial reaction force load with respect to the collision input, as shown in FIG.
The initial reaction force load decreases as b increases, but Lb is La
The initial resistance load exceeds dimensions, the resultant substantially constant as initial resistance load Pc ₁ equivalent values in the member body 1 in a simple rectangular closed cross section with no ribs therein (see FIG. 14). Furthermore, Lb is initial resistance load becomes asymptotic to the Pc ₁ in the vicinity of the dimension of 1 / 2La.

On the other hand, considering the buckling load-displacement characteristics of the member body 1 when the dimension Lb is set to La or more, as shown in FIG. 4, the initial reaction force load at the time of collision is Pc ₁ . However, the reaction force load decreases sharply thereafter, and then rises again, and the inclined portions 3a, 3a,
Beyond the intersection of 4a, the reaction force load is obtained as Pm ₂ and becomes substantially constant. However, in this case, since the reaction load suddenly drops at the initial stage of the buckling deformation at the time of the collision of the member main body 1, the provision of the vertical ribs 3 and the horizontal ribs 4 greatly reduces the collision energy absorption. Growth cannot be expected.

Therefore, the dimension L of the above-mentioned inclined portions 3a, 4a
b is 1 in consideration of the initial reaction force load, the amount of collision energy absorption, the bellows-like buckling deformation pitch of the member body 1 and the like.
/ 2La <Lb <La.

According to the structure of the above embodiment, when a collision input acts on the end of the member main body 1 at the time of a vehicle collision, the member main body 1 buckles and collapses together with the internal vertical ribs 3 and the horizontal ribs 4 to reduce the collision energy. In the initial stage of the collision, only the peripheral wall of the member main body 1 buckles due to the formation of the arc-shaped inclined portions 3a and 4a of the vertical ribs 3 and the horizontal ribs 4, and C in FIG.
As shown by the line, the initial reaction force load is obtained as Pc ₁ and can be kept low. When the buckling deformation advances from the position A shown in FIG. 2 to the position B, the cross-sectional areas of the vertical ribs 3 and the horizontal ribs 4 gradually increase, and the vertical ribs 3 and the horizontal ribs 4 also buckle. A sudden drop is avoided, and the buckling deformation proceeds after the intersection of the inclined portions 3a, 4a of the vertical ribs 3 and the horizontal ribs 4, so that the reaction force load becomes Pm ₂ and becomes substantially constant. Become. Accordingly, it is possible to reduce the impact force by suppressing the initial reaction force load at the time of a vehicle collision, and to increase the average reaction force load after the initial stage of the collision, thereby realizing an increase in the collision energy absorption. it can.

In the above-described embodiment, the case where the ribs in the member main body 1 are arranged to intersect with the vertical ribs 3 and the horizontal ribs 4 has been shown. In addition, as shown in FIG. The intended purpose can also be achieved by providing a plurality of lateral ribs 4 and forming the inclined portions 4a at the ends of the lateral ribs 4 in the same manner as described above.

FIGS. 6 and 7 show the side member SM having the above-described structure.
In case of using the inclined portion 3a, as a front side member SM ₁ by placing the end of 4a formed side in the vehicle body front portion, the front bumper 5 is attached to the front end portion of the front side member SM ₁ through the bumper stay 6 . The bumper stay 6 is formed by forming a notch 8 on the upper and lower edges and bending a bumper mounting portion 9 in one direction on the upper and lower edges of the front end, and by bending the rear portion of the stay body 7. Pressure receiving portion 1 engaged with the front end surface of member body 1
The bracket 11 formed to be bent rearward from the side edge of the pressure receiving portion 10 is inscribed in the side wall surface on one side of the member main body 1 and is fixed to the bolt and the nut. The bumper mounting portion 9 is reinforced by a stiffener 12 which is joined to a substantially rear half portion of a peripheral edge portion and is straddled in a vertical direction, and the front bumper 5 has a bracket 13 projecting from rear edges of upper and lower walls thereof overlapped with the bumper mounting portion 9. Bolts and nuts are fixed.

Therefore, in this embodiment, when the vehicle has a frontal collision, at the time of a light collision, only the stay body 7 is bent to one side starting from the notch 8 forming portion as shown in FIG. While absorbing energy and preventing deformation damage on the vehicle body side, when the degree of collision is large, the stay body 7
The bumper mounting portion 9 abuts against the pressure receiving portion 10 due to the bending deformation of the member, and the collision input acts on the end portion of the member main body 1 via the pressure receiving portion 10 on average, and the member main body 1 is buckled and deformed as described above. To absorb the collision energy.

FIG. 9 shows a different example of the bumper stay 6. The stay body 7 has a bellows portion 7a formed at an intermediate portion thereof, and a wedge which is inscribed on one side wall of the member body 1 on one side thereof. The part 14 is joined and arranged. Brackets 11a, 11a are provided on the upper and lower edges of the rear end of the stay body 7.
Are bent, and the bracket 11a is attached to the upper wall of the member main body 1 and the bracket 11b is overlapped to the side wall of the member main body 1 so that the bolt and the nut 15 are fixed and attached.

In this embodiment, at the time of a rear collision of the vehicle, as shown in FIG.
, And retreats into the member body 1. Along with this, one side wall of the member main body 1 is deformed inward by the wedge portion 14 to be a trigger for buckling deformation of the member main body 1, and the member main body 1 is buckled and deformed in the same manner as described above to reduce the collision energy. Absorb.

FIG. 11 shows the side member SM connected to the inclined portion 3a,
Shows the case of using as a rear side member SM ₂ by placing the end of 4a formed side rear portion of the vehicle body. Even in this embodiment, at the time of a rear collision of the vehicle, the member main body 1 is not accompanied by an increase in the initial reaction force load due to the formation of the inclined portions 3a and 4a (see FIG. 1) of the vertical ribs 3 and the horizontal ribs 4. Buckling deformation is started, and gradually buckling deformation is gradually performed in a bellows shape together with the internal vertical ribs 3 and the horizontal ribs 4, so that the collision energy can be efficiently absorbed. In the case of the rear side member SM _2, 11
As shown in the figure, in order to avoid interference with a suspension member and the like (not shown) on the rear side portion, an arch portion MA that curves upward is formed, so that the initial reaction force load at the time of a rear collision is high. It is conceivable that the stress is concentrated on the arch portion MA and the arch portion MA breaks as shown by a dashed line in FIG. , The bellows-like plastic deformation of the rear end portion of the member main body 1 can be gradually propagated to the front of the vehicle body, and effective collision energy absorption can be performed without causing breakage of the arch portion MA. be able to.

Although the side member SM has been described in the above embodiment, the same effect as described above can be obtained by applying the present invention to a side sill SS disposed in the vehicle longitudinal direction.

[0023]

As described above, according to the present invention, an inclined portion is formed at the end of the rib integrally formed in the closed cross section of the member main body, and the cross-sectional area of the rib from the end face side of the member main body. Is formed so as to gradually increase, so that when a collision input is applied to the end of the member main body, the initial reaction force load can be kept small, and the average reaction force load can be maintained high, so that the collision can be maintained. This has a great practical effect that the amount of energy absorption can be significantly increased.

[Brief description of the drawings]

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

FIG. 2 is a side view of the embodiment.

FIG. 3 is a characteristic diagram showing a relationship between the length of the inclined portion of the rib and the buckling load of the example.

FIG. 4 shows a buckling load of the member main body when the length of the inclined portion of the rib of the embodiment is longer than the length of the long side of the member main body.
Displacement characteristic diagram.

FIG. 5 is a perspective view showing a different example of the present invention.

FIG. 6 is an exploded perspective view showing an example in which the member main body of FIG. 1 is applied to a front side member.

FIG. 7 is a view taken in the direction of the arrow C in FIG. 6;

FIG. 8 is a plan view showing a deformed state of the bumper stay shown in FIGS.

FIG. 9 is a perspective view showing a different example of a bumper stay.

FIG. 10 is a plan view showing a deformed state of the bumper stay of FIG. 9;

FIG. 11 is a side view showing an example in which the member main body of FIG. 1 is applied to a rear side member.

FIG. 12 is a buckling load-displacement characteristic diagram of a member main body.

FIG. 13 is a perspective view showing a vehicle body frame structure of an automobile.

FIG. 14 is a perspective view showing the structure of a conventional member main body.

FIG. 15 is a perspective view showing a different example of a conventional member main body.

[Explanation of symbols]

 1. Member main body, 3, 4 rib, 3a, 4a inclined section.

Claims (1)

(57) [Claims] 1. A structure in which a rib that extrudes a closed cross section and is disposed in the longitudinal direction of a vehicle body and that integrally forms a rib that divides the closed cross section into a plurality of pieces in a longitudinal direction, the end of the rib. A vehicle body strength member structure for an automobile, characterized in that an inclined portion is formed in the portion from a connection point with a peripheral portion of the member main body toward the inside of the member main body.