JPH10338160A - Cross member connecting part structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax stress concentration to a specific connecting point between a reinforcing member and a cross member in case of vertical and longitudinal bending force and torque acting upon the cross member. SOLUTION: A gusset 20 is disposed at a connecting part between a side member 10 and a cross member 12. Joint parts 20A, 20B of the gusset 20 and the lower faces of flanges 12B, 12D of the cross member 12 are welded to each other by spot welding at weld points P1, P2, P3, P4, P5. Beads 26 are formed in semicircular cross section protruded downward between the weld point P1 to be the innermost end part in a vehicle cross direction out of the weld points, and the following weld point P2. These beads 26 are formed along an orthogonal direction to the axis 28 of the cross member 12 so as to be easily extended in the direction of the axis 28 of the cross member 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross member connecting structure, and more particularly to a cross member connecting structure applied to a ladder type frame of a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, as a cross member connecting portion structure 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. Is shown in Japanese Utility Model Laid-Open No. 4-51871.

As shown in FIG. 6, in this cross member connecting portion structure, a side member (also referred to as a side rail) is provided.
The upper gusset 102 as a reinforcing member having an L-shaped cross section is composed of a flat portion 102A joined to the inside of the upper flange 100A of the base member 100 and a side surface portion 102B joined to the inside of the wep 100B of the side member 100. The joint between the member and the cross member 104 is reinforced. In this cross member connecting portion structure, a plurality of reinforcing longitudinal beads 106 are formed on the side surface portion 102B of the upper gusset 102 which is bolted or riveted to the wedge 100B of the side member 100.

[0004]

However, in this cross member connecting portion structure, the cross member 104 and the upper gusset 102 are welded to each other, and the cross member 104 and the upper gusset 102 are welded inside the welding point P1, which is the innermost in the vehicle width direction. At the site, the upper gusset 102 having high rigidity is eliminated. For this reason, in this ladder-type frame, the rigidity difference sharply increases in the vehicle width direction inner part of the welding point P1 where the vehicle width direction inner end of the upper gusset 102 exists. As a result, the ladder-type frame is twisted during running of the vehicle, and vertical and longitudinal bending and torsional forces are applied to the cross member 104, and the upper gusset 102 is moved in the axial direction of the cross member 104 (in the direction of the arrow W in FIG. 6). When the tensile force and the compressive force are applied, most of these forces are received at the welding point P1 adjacent to the portion where the difference in rigidity is large. For this reason, stress concentrates around the welding point P1, and this stress concentration causes a crack to occur. Usually, since the thickness of the upper gusset 102 is larger than the thickness of the cross member 104, the stress concentration around the welding point P1 causes a crack on the cross member 104 side.

In view of the above facts, the present invention can alleviate the concentration of stress at a specific joining point between the reinforcing member and the cross member when a vertical and longitudinal bending force and a torsional force act on the cross member. It is an object of the present invention to provide a cross member connecting structure.

[0006]

According to a first aspect of the present invention, there is provided a pair of left and right side members disposed at lower portions of both ends in a vehicle width direction of a vehicle and extending in the vehicle front-rear direction. A cross member extending in the vehicle width direction, and a reinforcing member disposed at a connecting portion between the side member and the cross member and connected to the side member and the cross member. The cross-section between a first connection point on the innermost side in the vehicle width direction of the connection points of the reinforcing member with the cross member, and a second connection point adjacent to the first connection point on the outer side in the vehicle width direction. It is characterized by having a deformable portion that easily extends in the axial direction of the member.

[0007] Therefore, when a vertical and longitudinal bending force and a torsional force act on the cross member and a tensile force or a compressive force acts on the cross member in the axial direction thereof, the tensile force causes the cross member of the reinforcing member to move. A deformed portion formed between the first connection point which is the innermost in the vehicle width direction of the connection points with the second connection point and which is adjacent to the first connection point on the outside in the vehicle width direction extends in the axial direction of the cross member. . As a result, due to the deformation of the deformed portion, the rigidity of the cross member between the first connection point and the second connection point of the reinforcing member along the axial direction of the cross member is reduced, and the stress is reduced not only at the first connection point but also at the second connection point. Since the stress is also distributed to the connection points, stress concentration on the first connection points can be reduced.

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

Therefore, when a vertical and longitudinal bending force and a torsional force act on the cross member, and a tensile force and a compressive force act on the cross member in the axial direction, the tensile force causes the cross member of the reinforcing member to be acted upon. A bead formed between a first connection point on the innermost side in the vehicle width direction and a second connection point adjacent to the first connection point on the outside in the vehicle width direction extends in the axial direction of the cross member. As a result, due to the deformation of the bead, the rigidity of the cross member between the first joint point and the second joint point of the reinforcing member along the axial direction of the cross member is reduced, and the stress is reduced not only at the first joint point but also at the first joint point. Since the stress is also distributed to the two connection points, the stress concentration on the first connection point can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a cross member connecting portion structure of the present invention will be described with reference to FIGS.

In each of the drawings, an arrow FR is shown in front of the vehicle.
, The upper part of the vehicle is indicated by an arrow UP, and the inner side in the vehicle width direction is indicated by an arrow IN.

As shown in FIG. 1, the 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 at both lower ends of the vehicle in the vehicle width direction. A plurality of cross members 12 extending in the vehicle width direction are provided on the side member 10 (only the right side member of the vehicle is shown in FIG. 1).

[0013] As shown in FIG.
Has a side member outer panel 14 that forms the outside of the side member 10 in the vehicle width direction, and a side member inner panel 16 that forms the inside of the side member 10 in the vehicle width direction. The cross-sectional shape of the side member outer panel 14 as viewed from the vehicle front-rear direction is a U-shape with the opening directed inward in the vehicle width direction. In the joint portion with the cross member 12, the lower wall portion 14A has a vehicle width. A connecting portion 14B protruding inward is formed.

As shown in FIG. 3, the cross-sectional shape of the side member inner panel 16 when viewed from the front-rear direction of the vehicle has a U-shape with an opening directed 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 on the inner side in the vehicle width direction of the lower wall portion 14A of the side member outer panel 14. As a result, the side member 10 is formed with a closed cross-section 18 extending in the vehicle front-rear direction at a connection portion with the cross member 12 on which the side member inner panel 16 is provided.

As shown in FIG. 1, the cross-sectional shape of the cross member 12 as viewed from the vehicle width direction is a U-shape with an opening directed downward from the vehicle, and a lower end 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 on the outer end in the vehicle width direction of the upper wall portion 12E of the cross member 12 so as to extend outward in the vehicle width direction. Upper wall 14 of outer panel 14
It is welded to the upper surface of C at a welding portion 15.

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

As shown in FIG. 2, a gusset 20 as a reinforcing member is provided below the joint between the side member 10 and the cross member 12. As shown in FIG.
Is formed with a U-shaped notch 22 from the inside in the vehicle width direction. The front and rear sides of the notch 22 form joints 20A and 20B with the cross member 12, and the joints 20A and 20B gradually increase in width L in the front-rear direction outward in the vehicle width direction. ing. The outer portion 20C of the gusset 20 in the vehicle width direction is continuous in the front-rear direction.

As shown in FIG. 3, the outer side portion 20C of the gusset 20 in the vehicle width direction is overlapped 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 joints 20A and 20B of the gusset 20 are
B, 12D are welded to each other by spot welding at the welding point P1 as a first connecting point, the welding point P2 as a second connecting point, and the welding points P3, P4, and P5 as other connecting points on the lower surfaces. .

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

As shown in FIG. 4, these beads 26
Are formed along a direction perpendicular 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 (the direction of arrow A in FIG. 4).

Next, the operation of the embodiment will be described. In the cross member connecting portion structure according to the present embodiment, the ladder-type frame is twisted during running of the vehicle, so that the vertical and longitudinal bending and torsional forces act on the cross member 12, and the gusset 20 extends in the axial direction of the cross member 12. When a tensile force or a compressive force (in the direction of arrow A in FIGS. 3 and 4) acts, 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 this point and the point P2 extends in the axial direction of the cross member 12 (the direction of the arrow A in FIGS. 3 and 4) due to the tensile force.

As a result, in the cross member connecting portion structure of this embodiment, the gusset 20
The rigidity along the arrow A direction between the first welding point P1 and the second welding point P2 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, there is a difference in rigidity between the right and left of the first welding point P1 (the inside and the outside in the vehicle width direction) 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 in the conventional structure, the stress concentrated around the first welding point is dispersed also around the second welding point in the present embodiment. can do. Therefore, in the cross member connecting portion structure of the present embodiment, stress concentration on the first welding point P1 can be reduced, and generation of cracks can be suppressed.

The joining portion 20 of the gusset 20
In A and 20B, the stress applied to the bead 26 is higher than when the bead 26 is not provided. However, since the plate thickness of the gusset 20 is generally larger than the plate thickness of the cross member 12, the bead 26 It is extremely unlikely that cracks or the like will occur in the portion where the crack is provided.

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

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to such an embodiment, and various other embodiments are included in the scope of the present invention. It is clear to a person skilled in the art that is possible. For example, in the present embodiment, the bead 26 having a semicircular cross section as a deformed portion is formed on the gusset 20, but the cross sectional shape of the bead 26 may be 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 wavy bent portion.

In this embodiment, the joints 20A and 20B of the gusset 20 and the flange 1 of the cross member 12 are provided.
2B and 12D are joined to each other by spot welding. Instead of spot welding, the joining portions 20A and 20B of the gusset 20 and the flange 1 of the cross member 12 are formed by other configurations such as bolting, riveting, and arc welding.
2B and 12D may be combined.

In the present embodiment, the gusset 20 is provided below the cross member 12 and used as a so-called under gusset. However, the present invention can be used for an upper gusset. For example, as shown in FIG.
The gusset 20 may be provided also on the upper part of the second member 2.
In this case, the joining portions 20A, 2A
The upper gusset 2B is connected to the upper surface of the upper wall portion 12E of the cross member 12 by spot welding or the like.
The outer portion 20C in the vehicle width direction of 0 is welded to the upper wall portion 14C of the side member outer panel 14 at a connection portion 14D protruding inward in the vehicle width direction.

[0030]

According to the first aspect of the present invention, there is provided a pair of left and right side members disposed at the lower portions of both ends in the vehicle width direction of a vehicle and extending in the vehicle front-rear direction. In a cross member connecting portion structure comprising a cross member extending and a reinforcing member provided at a connecting portion between the side member and the cross member and connected to the side member and the cross member, the connecting of the reinforcing member to the cross member A deformable portion that easily extends in the axial direction of the cross member is provided between the first connection point that is the innermost in the vehicle width direction among the points and the second connection point that is adjacent to the first connection point on the outside in the vehicle width direction. When a vertical and longitudinal bending force and a torsional force are applied to the cross member, there is an excellent effect that stress concentration at a specific joining point between the reinforcing member and the cross member can be reduced.

According to a second aspect of the present invention, in the cross member connecting portion structure according to the first aspect, the deformed 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 the drawings]

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

FIG. 2 is an exploded perspective view showing a main part of the cross member connecting portion structure according to the embodiment of the present invention, as viewed obliquely from the rear inside the vehicle.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Side member 12 Cross member 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 (first joining point) P2 Welding point (No. (2 bonding points)

Claims (2)

[Claims] 1. A pair of left and right side members disposed at lower portions at both ends in a vehicle width direction of a vehicle and extending in the vehicle front-rear direction, a cross member spanned between the left and right side members and extending in the vehicle width direction, and the side members And a reinforcing member disposed at a connecting portion between the cross member and the cross member, the reinforcing member being connected to the side member and the cross member. A deformable portion that easily extends in the axial direction of the cross member is provided between a first connection point that is the innermost in the vehicle width direction and a second connection point that is adjacent to the outer side in the vehicle width direction of the first connection point. A cross member connecting portion structure. 2. The cross member connecting portion structure according to claim 1, wherein said deformed portion is a bead formed along a direction orthogonal to an axis of said cross member.