JP2002249066A - Hollow structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of component items and improve the productivity. SOLUTION: A rear side part 12A as a cabin side inner part of a suspension tower at a front part 12 of a front side member 10 has a square shaped cross section when observed from a vehicle longitudinal direction of a front side member lower 20. A cross section observed from the vehicle longitudinal direction of a front side member upper 22 has the channel shape having an opening part toward a lower part of the vehicle, and lower end parts 22C, 22D of left and right side wall parts 22A, 22B are respectively welded (welding part P) to upper end parts 20C, 20D of left and right side wall parts 20A, 20B of the front side member lower 20 by one side welding such as laser welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hollow structure,
In particular, the present invention relates to a hollow structure constituting a frame member of a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, in a hollow structure constituting a skeletal member of a vehicle such as an automobile, one example thereof is disclosed in JP-A-9-19.
3832.

As shown in FIG. 5, in this hollow structure, a center pillar 100 as a hollow structure is composed of an outer panel 102, an inner panel 104, and a lower reinforcement 106. These members 102, 104, and 106 are formed in a gutter shape without a flange.
, Both side pieces 102A, 102B, 104A, 104B,
106A and 106B are superimposed in parallel with each other, and have a cross-shaped letter shape.

[0004]

However, in this hollow structure, three parts, an outer panel 102, an inner panel 104, and a lower reinforcement 106, are used in order to make the cross section into a letter-shaped cross section. Many points. Further, in this hollow structure, each of the three side parts 102A, 10A of the outer panel 102, the inner panel 104, and the lower reinforcement 106 is provided.
Since 4A, 106A and 102B, 104B, 106B are simultaneously welded, three parts are welded simultaneously. As a result, even if laser welding, which is one of the advantages of high speed, is used, the heat input must be increased in order to increase the welding strength of the three parts, and the welding speed cannot be sufficiently increased. For this reason, welding work efficiency is poor and productivity is not good.

The present invention has been made in view of the above circumstances, and has as its object to obtain a hollow structure capable of reducing the number of parts and improving productivity.

[0006]

According to the first aspect of the present invention, a hollow structure having a U-shaped cross-section is welded to a structure having a U-shaped cross-section by one-side welding, and is formed into a letter-shaped cross-section. It is characterized by having.

[0007] Therefore, since the cross-sectional shape can be formed by the two members of the rectangular cross-sectional structure and the U-shaped cross-sectional structure, the number of parts can be reduced. In addition, since the two members, that is, the structure having the U-shaped cross section and the structure having the U-shaped cross section are welded by one-side welding, the welding work efficiency is improved and the productivity is improved.

According to a second aspect of the present invention, in the hollow structure according to the first aspect, the welded portion is located near a center in a width direction of a wall portion having the welded portion.

Therefore, in addition to the contents described in claim 1,
Normally, the energy absorption efficiency is poor in the vicinity of the center in the width direction of the wall with respect to the deformation in the axial direction. Since the efficiency is improved, the energy absorption efficiency of the entire hollow structure is improved.

According to a third aspect of the present invention, in the hollow structure according to any one of the first and second aspects, at least one of the four corners in the cross-shaped letter is formed as an inclined surface. .

Therefore, in addition to the contents described in any one of the first and second aspects, at least one of the four corners in the cross-section in the shape of a letter is an inclined surface. The ridge line extending in the axial direction of the hollow structure increases. Therefore, the strength and rigidity of the hollow structure in the axial direction are improved, and the amount of energy absorption can be increased.

According to a fourth aspect of the present invention, in the hollow structure according to the first to third aspects, a screw member is fixed to two opposing walls of the structure having a rectangular cross section. It is characterized by.

Therefore, in addition to the contents described in any one of claims 1 to 3, the screwing member is fixed to the two opposing walls of the structure having a rectangular cross section so that the screwing member is hollow. There is no need to separately provide reinforcement for fixing to the structure.

According to a fifth aspect of the present invention, in the hollow structure according to any one of the first to fourth aspects, the member having a cross-shaped letter is a side member.

Therefore, in addition to the contents described in any one of claims 1 to 4, it is possible to form an inexpensive side member having good energy absorption efficiency at the time of collision.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a hollow structure according to the present invention will be described with reference to FIGS.

In the drawings, an arrow FR indicates a forward direction of the vehicle, an arrow UP indicates an upward direction of the vehicle, and an arrow IN indicates an inward direction of the vehicle width.

As shown in FIG. 3, the hollow structure of the present embodiment is applied to a front side member 10, and the front side member 10 is provided near the lower end of the vehicle front in the vehicle width direction along the vehicle front-rear direction. The left and right front side members are not shown. The front part 12 of the front side member 10 is disposed in the engine room,
The rear portion 14 extends rearward of the vehicle along the inclined portion 16 </ b> A of the dash panel 16 and the lower surface of the floor panel 18.

As shown in FIG. 1, a front portion 12 of the front side member 10 has a front side member lower 2 as a structure constituting a lower portion of the front side member 10.
0 and a front side member upper 22 as a structure constituting the upper part of the front side member 10.

As shown in FIG. 3, a rear side portion 12A of the front portion 12 of the front side member 10 which is an inner side portion of the suspension tower 26 on the passenger compartment side is a cross-sectional shape of the front side member lower 20 viewed from the vehicle front-rear direction. Has a square shape as shown in FIG.

As shown in FIG. 1, the cross-sectional shape of the front side member upper 22 as viewed from the vehicle front-rear direction is a U-shape with the opening directed downward from the vehicle, and the left and right side wall portions 22A and 22B are formed. The lower ends 22C and 22D are respectively provided on the left and right side walls 2 of the front side member lower 20.
The welding portions P are welded to the upper end portions 20C and 20D of the first and second welding portions 0A and 20B, respectively, by one-side welding in which welding is performed only from one side of a welding surface such as laser welding, arc welding, or plasma welding, that is, from the outer peripheral side of the front side member upper 22. Are welded. As a result, the cross-sectional shape of the front side member 10 as viewed from the vehicle front-rear direction is a Japanese character.

The height H1 of the front side member lower 20 and the height H2 of the front side member upper 22
From the front side member 10
The width W (the length in the vertical direction of FIG. 1) W of the left and right side walls 12C and 12D in the front part 12 of FIG.

The upper wall 20E of the front side member lower 20 and the lower wall 20 opposed to the upper wall 20E.
In F, through holes 40 and 42 are respectively formed,
A nut 44 as a screw member is inserted into the through holes 40 and 42 from below. Also, nut 44
Is welded to both the upper wall 20E and the lower wall 20F of the front side member lower 20 by arc welding, and a suspension lower arm 48 is attached to a lower portion of the front side member 10 by a bolt 46 screwed to a nut 44. Have been.

As shown in FIG. 3, at the front portion 12B of the front portion 12 of the front side member 10 which is closer to the front of the vehicle than the suspension tower 26, as shown in FIG. On the other hand, in the present embodiment, inclined surfaces 50, 52, 54, 56 are formed at all four corners, and upper and lower end edges of each inclined surface 50, 52, 54, 56 extend in the vehicle front-rear direction, respectively. The ridge lines 58, 60, 62, 64, 66, 68, 70, 72 are provided.

As shown in FIG. 3, the rear part 14 of the front side member 10 is constituted only by the front side member lower part 20, and the rear part 14 of the front side member 10 is formed by the upper wall part 20 of the front side member lower part 20.
A recess 74 having a rectangular cross section extending in the front-rear direction is formed in E. Also, the front side member lower 20
Inclined portion 16 of dash panel 16 facing concave portion 74 of
A bead 76 having a rectangular cross section protruding upward is formed in each part of the A and the floor panel 18 along the front-rear direction.

Next, the operation of the present embodiment will be described.

When the vehicle collides forward, the front portion 12 of the front side member 10 is compressed and deformed in the vehicle longitudinal direction. At this time, the front part 1 of the front side member 10 of the present embodiment is
2, since the cross-sectional shape as viewed from the front-back direction is a Japanese character, the wavelength λ1 as shown by a pair of upper and lower two-dot chain lines or a lower two-dot chain line and an upper broken line in FIG. As a result, the front portion 12 of the front side member 10 is compressed and deformed as shown in FIG. For this reason, as shown in FIGS. 6A and 6B, the compression deformation of the front side members 80 and 82 of the conventional structure having a rectangular cross section when viewed from the vehicle front-rear direction is shown in FIG. ) Is a wavelength λ2 as shown by a pair of an upper and lower two-dot chain line or a lower two-dot chain line and an upper dashed line.
7B, the wavelength λ1 of the present embodiment is much shorter than the wavelength λ2 of the conventional structure.

As a result, the wall amplitude at the time of compressive deformation in the present embodiment is significantly reduced, the fluctuation of the welded portion P is smaller than in the conventional structure, and the load on the welded portion P is reduced.
For this reason, since the welding strength in the present embodiment can be made lower than the welding strength of the conventional structure, high-speed welding by laser welding becomes possible, and productivity can be improved. Furthermore, in the present embodiment, the impact acting on the welded portion P can be reduced as compared with spot welding such as spot welding by making the welded portion P a continuous line weld in the vehicle longitudinal direction by laser welding or the like.

As shown in FIGS. 6 (A) and 6 (B), the front side members 80 and 82 of a conventional structure having a rectangular cross section as viewed from the vehicle front-rear direction have left and right side wall portions 80A. , 80B, 82A, and 82B in the vicinity of the central portion S in the width direction becomes a portion where the energy absorption efficiency is low particularly when the plate thickness is reduced. In the present embodiment, FIG.
As shown in FIG.
0, which is near the center of the width W (length in the vertical direction in FIG. 1) W of the left and right side walls 12C and 12D in the front part 12 of FIG. Thus, even when the plate thickness is reduced for weight reduction, the energy absorption efficiency of the entire front portion 12 of the front side member 10 is improved.

In the present embodiment, the front side portion 12B of the front portion 12 of the front side member 10 has inclined surfaces 50, 52, 54, 56 at the four corners of the cross section in the shape of a letter.
Are formed, and the upper and lower edges of each of the inclined surfaces 50, 52, 54, 56 are ridge lines 58, 60, 62, 64, 66, 68, 70, 72 extending in the vehicle longitudinal direction, respectively.
It has become. As a result, the number of ridges of the front side member 10 extending in the vehicle longitudinal direction (axial direction) increases,
The strength and rigidity in the axial direction of the front side member 10 are improved, and the amount of energy absorption can be increased.

As shown in FIG. 6 (C), the front side member 84 of the conventional structure in which the cross-sectional shape viewed from the front-rear direction of the vehicle has a Japanese character shape has three members 84A, 84A.
B and 84C need to be welded at the welded portions P1, P2, P3 and P4, respectively. In the present embodiment, as shown in FIG. 1, a front side member lower 20 having a U-shaped cross section and a U-shaped cross section are provided. The front side member upper 22 and the two members can form a cross-shaped letter, so that the number of parts can be reduced, the weight can be reduced and the cost can be reduced, and the number of welded portions P can be reduced to two, thereby improving the productivity. .

In this embodiment, since there are no welded portions at the four corners of the cross section of the letter shaped to receive a large load in the event of a collision, there is no need to worry about welding peeling which has conventionally been caused by receiving a large load. Energy absorption can be secured. Further, in the present embodiment, since the welded portion P is set at a portion where the load received at the time of collision is smaller than the four corners of the cross-section in the shape of a letter, the load on the welded portion P can be reduced.

As shown in FIG. 6D, in the front side member 86 having the conventional structure, the reinforcement 8 is fixed in order to fix the nut 44 as a screw member.
In this embodiment, the upper wall 20E and the lower wall 20F of the front side member lower 20 need to be provided separately.
Since the nut 44 serving as a screw member is welded to the screw, there is no need to separately provide a reinforcement 88, and the number of components can be reduced.

Further, in this embodiment, since the hollow structure of the present invention is applied to the front side member 10, the front side member 10 having good energy absorption efficiency at the time of collision, light weight and low cost can be formed.

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 front side member 10 as a hollow structure in the above-described embodiment, the cross-sectional shape of the front side member lower 20 as viewed from the vehicle front-rear direction is rectangular, and the cross-section of the front side member upper 22 as viewed from the vehicle front-rear direction. The shape is a U-shape with the opening directed downward from the vehicle, but instead of this, the front side member upper 22
The cross-sectional shape of the front side member lower 20 viewed from the vehicle front-rear direction may be a U-shape with the opening directed upward from the vehicle.

In the above-described embodiment, the nut 44 as a screw member is welded to both the upper wall portion 20E and the lower wall portion 20F of the front side member lower 20, but instead of this, the front side member lower portion is replaced. In addition to the upper wall portion 20E and the lower wall portion 20F, a through hole is formed in the upper wall portion 22C of the front side member upper 22 shown in FIG. 1, and an upper end portion of the nut 44 is extended to form the through hole. It may be configured to be inserted and welded to the base.

In the above embodiment, as shown in FIG. 2, the front side 12B of the front portion 12 of the front side member 10 which is closer to the front of the vehicle than the suspension tower 26 has all four corners in a cross section of a Japanese character. Slope 50,
Although 52, 54 and 56 are formed and the cross-sectional shape is octagonal, the number of inclined surfaces is not limited to four, and the cross-sectional shape may be a polygon other than octagon.

In the above embodiment, as shown in FIG. 1, the screw member is the nut 44 to which the bolt 46 for attaching the suspension lower arm 48 is screwed. It is not limited to the nut 44 to which the bolt 46 for mounting is screwed, but may be a nut to which a bolt for mounting another member is screwed, or may be a bolt.

In the above embodiment, the hollow structure of the present invention is applied to the front side member 10. However, the hollow structure of the present invention is not limited to the front side member, but may include other side members, cross members, upper members, rockers. Etc. can be applied to other body frame members.

[0040]

According to the first aspect of the present invention, the hollow structure has a U-shaped cross-section which is welded to a U-shaped cross-section by single-side welding to form a cross-shaped Japanese character. It has an excellent effect that the number of parts can be reduced and productivity can be improved.

According to the second aspect of the present invention, in the hollow structure according to the first aspect, the welded portion is located near the center in the width direction of the wall having the welded portion. In addition to this, there is an excellent effect that the energy absorption efficiency of the entire hollow structure is improved.

According to a third aspect of the present invention, in the hollow structure according to any one of the first and second aspects, at least one of the four corners in the shape of a cross section is an inclined surface. In addition to the effects described in any one of the above, there is an excellent effect that the amount of energy absorption can be increased.

According to a fourth aspect of the present invention, in the hollow structure according to the first to third aspects, a screw member is fixed to two opposing walls of the structure having a rectangular cross section. In addition to the effects described in any one of claims 1 to 3, there is an excellent effect that it is not necessary to separately provide a reinforcement for fixing the screw member to the hollow structure.

According to a fifth aspect of the present invention, in the hollow structure according to the first to fourth aspects, the member having a cross-shaped letter is a side member. In addition to this, there is an excellent effect that energy absorption efficiency at the time of collision is good and an inexpensive side member can be formed.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view taken along line 1-1 of FIG.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG.

FIG. 3 is a perspective view showing a hollow structure according to an embodiment of the present invention, as viewed from the inside of the vehicle diagonally rearward.

FIG. 4A is an explanatory diagram showing a compression wavelength when a hollow structure according to one embodiment of the present invention is deformed, and FIG. 4B is a diagram after a hollow structure according to one embodiment of the present invention is deformed; It is explanatory drawing which shows the shape of.

FIG. 5 is a cross-sectional view showing a conventional hollow structure.

FIGS. 6A to 6D are cross-sectional views showing a conventional hollow structure.

FIG. 7A is an explanatory diagram showing a compression wavelength of a conventional hollow structure when deformed, and FIG. 7B is an explanatory diagram showing a shape of the conventional hollow structure after deformation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Front side member (hollow structure) 12 Front part of front side member 14 Rear part of front side member 20 Front side member lower (structure having a cross section of a rectangular shape) 20C Upper end part of front side member lower 20F Front part member lower Lower wall portion 22 Front side member upper (structure having a U-shaped cross section) 44 Nut (screw member) 50 Inclined surface 52 Inclined surface 54 Inclined surface 56 Inclined surface

Claims (5)

[Claims] 1. A hollow structure wherein a structure having a U-shaped cross section is welded to a structure having a U-shaped cross section by one-side welding to form a C-shaped cross section. 2. The hollow structure according to claim 1, wherein the welded portion is located near a central portion in a width direction of a wall portion having the welded portion. 3. The hollow structure according to claim 1, wherein at least one of the four corners of the cross-section in the shape of a letter has an inclined surface. 4. The hollow structure according to claim 1, further comprising a screw member fixed to two opposing walls of the structure having a rectangular cross section. 5. The hollow structure according to claim 1, wherein the member having a cross section in the shape of a letter is a side member.