JP3465532B2 - Cross member connection 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 cross member joint structure, and more particularly to a cross member joint structure applied to a ladder frame of a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, as a structure of a cross member connecting portion applied to a ladder type frame of a vehicle such as an automobile, a structure in which a reinforcing member is provided at a connecting portion between a cross member and a side member is known, and an example thereof is known. Is disclosed in Jitsukaihei 4-51871.

As shown in FIG. 6, in this cross member joint structure, side members (also called side rails) are used.
The upper gusset 102, which is a reinforcing member having an L-shaped cross section, is configured by a flat surface portion 102A joined to the inside of the upper flange 100A of 100 and a side surface portion 102B joined to the inside of the web 100B of the side member 100. The joint between the cross member 104 and the cross member 104 is reinforced. In this cross member joint structure, a plurality of vertical beads 106 for reinforcement are formed on the side surface 102B of the upper gusset 102 that is bolted or riveted to the web 100B of the side member 100.

[0004]

However, in this cross member joint structure, the cross member 104 and the upper gusset 102 are welded together, and the welding point P1 on the innermost side in the vehicle width direction is located on the innermost side in the vehicle width direction. The upper gusset 102, which has high rigidity, is eliminated in the region. Therefore, in this ladder-shaped frame, the difference in rigidity suddenly increases at the portion on the vehicle width direction inner side of the welding point P1 where the vehicle width direction inner end of the upper gusset 102 exists. As a result, vertical and forward / backward bending forces and twisting forces act on the cross member 104 due to twisting of the ladder frame when the vehicle is running, and the upper gusset 102 is subjected to the axial direction of the cross member 104 (direction of arrow W in FIG. 6). ), The majority of these forces are received at the welding point P1 adjacent to the site where the difference in rigidity is large. Therefore, stress concentrates around the welding point P1, and this stress concentration causes a crack to occur. Since the plate thickness of the upper gusset 102 is usually thicker than the plate thickness of the cross member 104, the stress concentration around the welding point P1 causes cracks on the cross member 104 side.

In consideration of the above facts, the present invention can alleviate stress concentration at a specific connecting point between the reinforcing member and the cross member when vertical and front-back bending forces and twisting forces act on the cross member. An object is to provide a cross member joint structure.

[0006]

According to a first aspect of the present invention, there is provided a pair of left and right side members which are disposed at lower end portions of both ends of a vehicle in a vehicle width direction and extend in the vehicle front-rear direction, and are installed between the left and right side members. And a reinforcing member that is disposed at a joint between the side member and the cross member and that is coupled to the side member and the cross member. the the definitive between a first coupling point of the most inboard of the coupling point between the reinforcing member and the cross member, and a second coupling point adjacent to the outside in the vehicle width direction of the first coupling point, Supplement
It is characterized in that a deformable portion that easily extends in the axial direction of the cross member is formed at the portion of the strong member .

Therefore, when vertical and longitudinal bending forces and torsional forces act on the cross member and tensile and compressive forces in the axial direction act on the cross member, the tensile force acts on the cross member of the reinforcing member. The deformed portion formed between the first connection point that is the innermost in the vehicle width direction and the second connection point that is adjacent to the outer side of the first connection point in the vehicle width direction extends in the axial direction of the cross member. . As a result, due to the deformation of the deformable portion, the rigidity of the cross member between the first connecting point and the second connecting point of the reinforcing member along the axial direction is reduced, and the stress is applied not only to the first connecting point but also to the second connecting point. Since it is also dispersed to the bonding points, stress concentration on the first bonding points can be relaxed.

According to a second aspect of the present invention, in the cross member connecting portion structure according to the first aspect, the deforming portion is a bead formed along a direction orthogonal to an axis of the cross member. There is.

Therefore, when vertical and longitudinal bending forces and torsional forces act on the cross member, and tensile and compressive forces in the axial direction act on the cross member, the tensile force acts on the reinforcing member and the cross member. most cars and first coupling point in the width direction inner side, the bead cross member which is formed at a portion of the definitive reinforcement member between the second coupling point adjacent to the outer side in the vehicle width direction of the first coupling point of the coupling point between the Extending in the axial direction. As a result, the deformation of the bead reduces the rigidity along the axial direction of the cross member between the first connection point and the second connection point of the reinforcing member, so that the stress is exerted not only on the first connection point but also on the second connection point.
Since it is also dispersed to the bonding points, stress concentration on the first bonding points can be relaxed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a cross member connecting portion structure of the present invention will be described with reference to FIGS.

In each drawing, the arrow FR indicates the front of the vehicle.
An arrow UP indicates the upper side of the vehicle and an arrow IN indicates the inner side in the vehicle width direction.

As shown in FIG. 1, the vehicle body frame in the cross member connecting portion structure of the present embodiment is a so-called ladder frame, and a pair of left and right extending in the vehicle front-rear direction is formed at the lower ends of the vehicle width direction. The side member 10 (only the side member on the right side of the vehicle is shown in FIG. 1) is provided with a plurality of cross members 12 extending in the vehicle width direction.

As shown in FIG. 2, the side member 10
Has a side member outer panel 14 that constitutes the outside of the side member 10 in the vehicle width direction, and a side member inner panel 16 that constitutes the inside of the side member 10 in the vehicle width direction. The cross-sectional shape of the side member outer panel 14 when viewed from the vehicle front-rear direction is a U-shape with the opening facing inward in the vehicle width direction, and at the joint portion with the cross member 12, the vehicle width is reduced to the lower wall portion 14A. A connecting portion 14B protruding inward is formed.

As shown in FIG. 3, the sectional shape of the side member inner panel 16 as viewed from the vehicle front-rear direction is a U-shape with the opening facing outward in the vehicle width direction.
6A is an upper wall portion 14C of the side member outer panel 14
Is welded to the lower surface on the inner side in the vehicle width direction. Also,
The lower wall portion 16B of the side member inner panel 16 is welded to the upper surface of the lower wall portion 14A of the side member outer panel 14 on the inner side in the vehicle width direction. As a result, the side member 10 has a closed cross-section portion 18 extending in the vehicle front-rear direction at the joint portion with the cross member 12 in which the side member inner panel 16 is disposed.

As shown in FIG. 1, a cross-sectional shape of the cross member 12 as viewed from the vehicle width direction is a U-shape with an opening facing downward of the vehicle, and a lower end portion of the front wall portion 12A has A flange 12B is formed toward the front of the vehicle. A flange 12D is formed at the lower end of the rear wall 12C of the cross member 12 toward the rear of the vehicle.

As shown in FIG. 3, a flange 12F is formed at the vehicle width direction outer end of the upper wall portion 12E of the cross member 12 toward the vehicle width direction outside, and the flange 12F is formed on the side member. Upper wall portion 14 of the outer panel 14
It is welded to the upper surface of C at the welded portion 15.

As shown in FIG. 4, a flange 12G is formed at the vehicle width direction outer end of the front wall portion 12A of the cross member 12 toward the front of the vehicle.
G is welded to the vertical wall portion 16C of the side member inner panel 16 at the welding portion 17. A flange 12H is formed at the vehicle width direction outer end of the rear wall portion 12C of the cross member 12 toward the rear of the vehicle. The flange 12H is formed on the vertical wall portion 1 of the side member inner panel 16.
6C is welded at the welded portion 19.

As shown in FIG. 2, a gusset 20 as a reinforcing member is disposed below the joint between the side member 10 and the cross member 12, and this gusset 20 is provided.
A U-shaped cutout 22 is formed in the vehicle width direction from the inside. The front and rear sides of the notch 22 are joint portions 20A and 20B with the cross member 12, and the joint portions 20A and 20B have a width L in the front-rear direction that gradually increases toward the outer side in the vehicle width direction. ing. Further, the vehicle width direction outer side portion 20C of the gusset 20 is continuous in the front-rear direction.

As shown in FIG. 3, the vehicle width direction outer side portion 20C of the gusset 20 is superposed on the upper surface of the connecting portion 14B of the side member outer panel 14, and is welded at the welding portion 22.

As shown in FIG. 4, the joint portions 20A and 20B of the gusset 20 are formed on the flange 12 of the cross member 12.
The welding points P1 as the first connecting points, the welding points P2 as the second connecting points, and the welding points P3, P4, P5 as the other connecting points are welded to each other by spot welding on the lower surfaces of B and 12D. .

As shown in FIG. 3, each welding point P1, P
2, P3, P4, and P5 are formed at predetermined intervals from the inside in the vehicle width direction toward the outside in the vehicle width direction, and the welding point P5 at the outermost side in the vehicle width direction is the connecting portion of the side member outer panel 14. Polymerized on top of 14B. In addition, a bead 26 as a deformed portion projects downward between a welding point P1 that is the innermost end in the vehicle width direction, that is, an end that is closest to the cross member 12 and a next welding point P2. It has a semicircular cross section.

As shown in FIG. 4, these beads 26
Are formed along a direction orthogonal to the axis 28 of the cross member 12, and are easily extended in the direction of the axis 28 of the cross member 12 (direction of arrow A in FIG. 4).

Next, the operation of the embodiment will be described. In the cross member joint structure of the present embodiment, vertical and forward / backward bending forces and torsional forces act on the cross member 12 due to twisting of the ladder frame during vehicle travel, and the gusset 20 is axially oriented. When a tensile force and a compressive force (in the direction of arrow A in FIGS. 3 and 4) act, the first welding point P1 closest to the cross member side end of the joints 20A and 20B in the gusset 20 and the next second welding The bead 26 formed between the point P2 and the point P2 extends in the axial direction of the cross member 12 (direction of arrow A in FIGS. 3 and 4) due to this tensile force.

As a result, in the cross member connecting portion structure of this embodiment, the deformation of the bead 26 causes the gusset 20 to be deformed.
Between the first welding point P1 and the second welding point P2, the rigidity along the direction of the arrow A is reduced, and the stress is reduced to the first welding point P1.
Not only is it dispersed to the second welding point P2. That is, the left and right sides of the first welding point P1 (the inner side in the vehicle width direction and the outer side in the vehicle width direction) have different rigidity depending on the presence or absence of the gusset 20, but the bead 26 provided inside the first welding point P1 is intentionally deformed. By doing so, the difference in rigidity between the left and right of the first welding point P1 can be reduced, and the stress concentrated around the first welding point in the conventional structure is dispersed also around the second welding point in the present embodiment. can do. Therefore, in the cross member joint structure of the present embodiment, the stress concentration at the first welding point P1 can be relaxed and the occurrence of cracks can be suppressed.

The joint portion 20 in the gusset 20
In A and 20B, the stress on the bead 26 is higher than in the case where the bead 26 is not provided, but since the plate thickness of the gusset 20 is usually thicker than the plate thickness of the cross member 12, the bead 26 of the gusset 20 is It is extremely unlikely that a crack or the like will occur at the portion where the mark is provided.

Further, in the structure of the cross member connecting portion of the present embodiment, the bead 26 as the deforming portion is formed on the gusset 20, so that the structure is simple and the productivity is good.

In the above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited to such embodiments, and various other embodiments within the scope of the present invention. It is obvious to a person skilled in the art that For example, in the present embodiment, the bead 26 having a semicircular cross section as the deformable portion is formed in the gusset 20, but the cross section of the bead 26 may have another shape such as a triangular shape. Further, the number of the beads 26 may be plural, and instead of the beads 26, the deformed portion may be configured by another configuration such as a bent portion bent in a wave shape.

Further, in this embodiment, the joint portions 20A and 20B of the gusset 20 and the flange 1 of the cross member 12 are joined.
2B and 12D are connected to each other by spot welding, but instead of spot welding, other configurations such as bolting, riveting, and arc welding may be used to join the joints 20A and 20B of the gusset 20 and the flange 1 of the cross member 12.
You may combine 2B and 12D.

Further, in the present embodiment, the gusset 20 is provided below the cross member 12 and used as a so-called under gusset, but the present invention can also be used for an upper gusset. For example, as shown in FIG.
A configuration in which the gusset 20 is provided on the upper part of the second unit 2 may also be used.
In this case, the joint portions 20A, 2 of the gusset 20 are
0B is joined to the upper surface of the upper wall portion 12E of the cross member 12 by spot welding or the like, and the upper gusset 2
A vehicle width direction outer side portion 20C of 0 is welded to an upper wall portion 14C of the side member outer panel 14 to a connecting portion 14D formed to project inward in the vehicle width direction.

[0030]

According to the first aspect of the present invention, a pair of left and right side members disposed in the lower portions of both ends of the vehicle in the vehicle width direction and extending in the vehicle front-rear direction, and erected between the left and right side members in the vehicle width direction. In a cross member joint structure having a cross member extending and a reinforcing member arranged at a joint between the side member and the cross member and joined to the side member and the cross member, the joint between the reinforcing member and the cross member most cars and first coupling point in the width direction inner side, definitive and a second coupling point adjacent to the outer side in the vehicle width direction of the first coupling point, between the complement of the point
Since a deformable portion that easily extends in the axial direction of the cross member is formed in the strong member portion, when a vertical and front-back bending force and a twisting force are applied to the cross member, a specific connecting point between the reinforcing member and the cross member. It has an excellent effect that stress concentration on the surface can be relaxed.

According to a second aspect of the present invention, in the cross member connecting portion structure according to the first aspect, the deforming portion is a bead formed along a direction orthogonal to the axis of the cross member. In addition to the effect, it has an excellent effect that the structure is simple.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a cross member coupling portion structure according to an embodiment of the present invention, as seen from a vehicle diagonally inner rear side.

FIG. 2 is an exploded perspective view showing a main part of the cross member coupling portion structure according to the embodiment of the present invention, as seen from the vehicle diagonally inner rear side.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a plan view showing a main part of the cross member coupling portion structure according to the embodiment of the present invention.

FIG. 5 is a perspective view showing a main part of a cross member coupling portion structure according to another embodiment of the present invention, as seen from a vehicle obliquely inner rear side.

FIG. 6 is a perspective view showing a cross member coupling portion structure according to a conventional embodiment.

[Explanation of symbols]

10 side members 12 cross members 14 Side member outer panel 16 Side member inner panel 18 Closed section 20 gusset (reinforcing member) 26 bead (deformation part) 28 Cross member axis P1 Welding point (1st connection point) P2 Welding point (second connecting point)

Claims (2)

(57) [Claims] 1. A pair of left and right side members which are disposed at lower ends of both ends of a vehicle in the vehicle width direction and extend in the vehicle front-rear direction, a cross member which is provided between the left and right side members and extends in the vehicle width direction, and the side member. In a cross member connecting portion structure including a side member and a reinforcing member that is connected to the cross member and is provided in a connecting portion between the reinforcing member and the cross member, among the first coupling point of the most inner side in the vehicle width direction, the reinforcing portion definitive between the second coupling point adjacent to the outside in the vehicle width direction of the first coupling point,
Cross member coupling part structure, wherein a portion of the timber that the the formation of the easily deformable portion extends in the axial direction of the cross member. 2. The cross member joint structure according to claim 1, wherein the deforming portion is a bead formed along a direction orthogonal to an axis of the cross member.