JP2003175857A - Aluminum alloy sub-frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy sub-frame capable of being manufactured with ease and high accuracy. <P>SOLUTION: An upper backing plate 3T, attached to a right member 1R, and a lower backing plate are inserted into one open end of a main member 1C, with the plate surface conformed with the inner surface of the open end. An upper backing plate 3T, attached to a left member 1L, and a lower backing plate are inserted in the other open end of the main member 1C, with the plate surface conformed with the inner surface of the open end. The main member 1C, the right member 1R, and the left member 1L are connected together by butt welding with welding beads 2 formed between them. A suspension sub-frame 10 is fixed on the main frame and mounted in the car body so that the main member 1C runs in the car width direction and the right member 1R and the left member 1L run in the car travel direction (or longitudinal direction). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy subframe mounted on a passenger car or the like, and more particularly to an aluminum alloy subframe with improved assembly accuracy.

[0002]

2. Description of the Related Art Hollow members made of steel are used for vehicle body frames such as suspension subframes of automobiles. 5A and 5B are views showing a structure of a conventional steel suspension subframe, in which FIG. 5A is a top view and FIG. 5B is a side view.

Steel suspension subframe 50
Is manufactured by, for example, bending a steel pipe of a predetermined length from both ends at equal positions to form a "U" shape in a plan view, and then performing a process called hydroforming. In hydroforming, a curved steel pipe is placed inside a mold to be transferred to a suspension subframe, and high-pressure water is pressed into the steel pipe to deform the steel pipe. Then, it is fixed to the main frame so that the central portion sandwiched between the two curved portions is located on the traveling direction side of the automobile. In addition,
As shown in FIG. 5 (a), a notch 51 is formed in the central portion of the steel suspension subframe 50, and as shown in FIG. 5 (b), the side portions are wavy in the vertical direction of the automobile. It has a curved shape.

In many cases, a front wheel of an automobile is fixed to the suspension subframe 50, and a mount portion (not shown) is attached to the suspension subframe 50 to mount an engine thereon. As described above, the notch 51 is formed and the side portions are curved, so that the suspension sub-frame 50 can be easily deformed at these portions when the vehicle has a frontal collision. This is because the engine is dropped below the vehicle body to prevent the heavy engine with high rigidity from narrowing the indoor space and further preventing the engine from jumping into the room.

Conventionally, such a suspension subframe made of steel has been widely used, but recently, from the viewpoint of weight reduction and the like, it has been considered to make it from an aluminum alloy.

[0006]

However, even if a suspension subframe made of an aluminum alloy is manufactured by adopting hydroforming similarly to that made of steel, an aluminum alloy material such as JIS 500 is used.
There is a problem that the 0-based or 6000-based alloy material is difficult to deform. It is also conceivable that a hollow suspension subframe is manufactured by manufacturing two members having a U-shaped cross section by press molding and assembling these by welding, but deformation occurs during welding. It is easy and difficult to satisfy the required dimensional accuracy.
Therefore, with this method, it is extremely difficult to obtain a suspension subframe having a desired shape.

The present invention has been made in view of such problems, and an object thereof is to provide an aluminum alloy subframe which can be easily manufactured with high accuracy.

[0008]

An aluminum alloy subframe according to the present invention is an aluminum alloy subframe to which a front wheel of an automobile is mounted, and a tubular first aluminum alloy member extending in the width direction of the automobile. A tubular second aluminum alloy member that is joined to one end of the first aluminum alloy member by welding and extends in the longitudinal direction of the automobile, and the other end of the first aluminum alloy member A tubular third aluminum alloy member which is joined to the portion by welding and extends in the longitudinal direction of the automobile.

In the present invention, since three members which are sequentially joined along the tube axis are provided, even if deformation such as twisting occurs at any of the joining portions, the deformation is absorbed at the other portions. It is possible to assemble with high accuracy. Also, when the member is made of an aluminum alloy whose strength is increased by heat treatment or processing, the strength around the joint can be made lower than other parts, so that it is easily deformed around the joint in the event of a collision. Can be made. Therefore,
Since the impact of the collision is absorbed in this portion, the engine or the like is less likely to jump into the room, and the safety of the passenger is improved.

By providing an aluminum alloy backing plate fixed to the inner surface of the joint between the first and second aluminum alloy members and the joint between the first and third aluminum alloy members. , It becomes easy to obtain a complete melted state that compensates for the soundness of the joint.

Also, the joint surfaces of the first and second aluminum alloy members and the joint surfaces of the first and third aluminum alloy members are substantially parallel to the longitudinal direction of the automobile. As a result, they are likely to be deformed especially in the case of a frontal collision.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an aluminum alloy subframe according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a view showing a suspension subframe made of an aluminum alloy according to an embodiment of the present invention, (a) is a top view and (b) is a side view. 2 is a sectional view taken along the line AA in FIG. 1A, and FIGS. 3 and 4 are exploded views showing a suspension subframe made of an aluminum alloy according to an embodiment of the present invention.

The aluminum alloy suspension subframe 10 according to this embodiment is provided with a central member 1C, a right member 1R and a left member 1L made of aluminum alloy. The right member 1R and the left member 1L are members corresponding to the curved portion of the steel pipe in the conventional steel suspension subframe 50 shown in FIG. 5 and the portion located on the end side of the curved portion, and have shapes symmetrical to each other. is doing. Therefore, the right member 1R and the left member 1L are provided with wavy portions in the vertical direction of the automobile. Further, the central member 1C is a member corresponding to a portion sandwiched by the curved portions of the steel pipe in the steel suspension subframe 50.

As shown in FIGS. 3 and 4, the central member 1C is provided with a central lower member 1CB located on the lower side and an upper central member 1CT located on the upper side when mounted on an automobile. There is. For example, the distance between the inner surface of the center lower member 1CB and the distance between the outer surface of the center upper member 1CT are the same, and both members are fillet welded with the center upper member 1CT fitted in the center lower member 1CB. Are joined by. Therefore, the central member 1C has a hollow shape with a closed cross section.

As shown in FIGS. 3 and 4, the right member 1R is located below the lower right member 1 when it is mounted on an automobile.
The RB and the upper right member 1RT located on the upper side are provided, and the left member 1L is provided with the lower left member 1LB located on the lower side and the upper left member 1LT located on the upper side when mounted on an automobile. For example, the lower right member 1RB and the lower left member 1
Distance between inner side surface of LB and upper right member 1RT and upper left member 1L
The distance between the outer side surface of T and the outside surface of T is the same, and the upper right member 1RT and the upper left member 1LT are the lower right member 1RB and the lower left member 1 respectively.
Both members are joined by fillet welding in a state of being fitted into the LB. Therefore, the right member 1R and the left member 1L also have a hollow shape with a closed cross section.

Central lower member 1CB, central upper member 1
CT, lower right member 1RB, upper right member 1RT, lower left member 1L
B and the upper left member 1LT can be obtained by press forming an aluminum alloy plate, for example.

Further, as shown in FIG. 3, the upper right member 1RT
An upper backing plate 3T made of an aluminum alloy protruding from the end is fixed to the inner surface of each end of the upper left member 1LT on the side of the central upper member 1CT, for example, by welding. Similarly, as shown in FIG. 4, the lower right member 1RB and the lower left member 1
A lower backing plate 3B made of an aluminum alloy protruding from the end is fixed to the inner surface of each end of the LB on the side of the central lower member 1CB, for example, by welding. The upper backing plate 3T is press-molded into a shape that follows not only the inner surfaces of the upper right member 1RT and the upper left member 1LT but also the inner surface of the central upper member 1CT.
Not only the inner surface of B but also the inner surface of the lower center member 1CB is press-formed.

Then, as shown in FIG. 1, an upper backing plate 3T and a lower backing plate 3B fixed to the right member 1R are inserted into one opening end of the central member 1C so as to follow the inner surface thereof, The upper backing plate 3T and the lower backing plate 3B fixed to the left member 1L are inserted into the other open end of the central member 1C so as to follow the inner surface of the central member 1C and the right member 1R and the left member 1L. Are joined by butt welding to form a weld bead 2 therebetween.

In the aluminum alloy suspension sub-frame 10 of this embodiment constructed in this way, the central member 1C extends in the width direction of the automobile, and the right member 1R and the left member 1L extend in the traveling direction (longitudinal direction) of the automobile. ) Is mounted in the body of the automobile so as to extend and is fixed to the main frame. Therefore, the central member 1C and the right member 1
The joint surface between the R and the left member 1L is a surface substantially parallel to the longitudinal direction of the vehicle, that is, a surface perpendicular to the width direction of the vehicle. Further, a bracket for holding arms supporting the front wheel shaft and a mount portion (not shown) are attached to the suspension subframe 10, and an engine, a main frame, and the like are mounted on the mount portion.

Since the hollow suspension sub-frame 10 according to this embodiment is composed of three members (left member 1L, central member 1C and right member 1R) which are sequentially joined along the tube axis, the torsion It is possible to absorb deformations such as the above and assemble with high accuracy. That is, as shown in FIG. 6A, when a hollow subframe is manufactured by simply welding two U-shaped members so that a welding line 5 is formed at their opposing portions. In particular, the length of the weld bead is largely different between the inner side and the outer side of the subframe, so that the deformation occurs and the end portion is significantly twisted. Also,
As shown in FIG. 6B, when only one joint surface 4 is provided and the hollow subframe is composed of two members, a warp occurs in the vicinity of the joint surface 4 and at the end portion of the subframe. There is an error in accuracy. On the other hand, according to the present embodiment, as shown in FIG. 6C, the sub-frame is composed of three members and the two joint surfaces 4 are provided. Even if a warp occurs, the warp can be offset by previously providing a gap at the butting at the time of welding on the other joint surface 4. Therefore, it is possible to manufacture a subframe having extremely high precision at the end portion.

Further, in this embodiment, the central member 1C is used.
The joint between the left member 1L and the right member 1R exists at the same position as the notch 51 in the conventional steel suspension subframe 50. At the joint, the base material is softened by the heating during welding. Therefore, when a frontal collision occurs, the suspension subframe 10 is easily deformed at this portion. Therefore, it is possible to prevent the engine from jumping into the room without forming a notch or the like at this position. However, in order to further weaken the strength in the vicinity of the joint portion, a notch or the like may be provided at that portion.

Further, in this embodiment, the backing plate 3T is used.
Since 3 and 3B are fixed to the left member 1L and the right member 1R, it is possible to secure sufficient penetration when joining with the central member 1C. Therefore, it is possible to prevent the strength of the joint portion from being lowered more than necessary and to secure the necessary minimum strength.

In the above embodiment, the central member 1C, the right member 1R and the left member 1L are all constructed by abutting and welding two members, but each is made of one aluminum alloy material. It may be composed of In addition, the central member 1C and the right member 1 are provided between both ends.
Although three members, R and the left member 1L, are provided, the present invention is not limited to this, and there are four members between both ends.
More than one member may be provided. Furthermore, it need not be strictly symmetrical.

The size of the suspension subframe 10 according to this embodiment in the longitudinal direction of the automobile is 60.
About 0 mm, the size in the width direction is about 800 mm,
The thickness of each member is about 4 mm, but the present invention is not limited to these sizes, and can be appropriately sized to the size of the body of the automobile. Further, as each member, for example, JIS 5000 series or 6
It is possible to use a 000 series aluminum alloy material, but the material is not limited to these.

[0025]

As described in detail above, according to the present invention,
Even if a deformation such as a twist occurs in the joint portion of any of the three members, the deformation can be absorbed in other parts and the assembly can be performed with high accuracy. Also, the strength of the joint is lower than other parts due to the influence of heat, so at the time of a collision it is easily deformed at the joint, and the impact of the collision is absorbed at this part,
The engine and the like are less likely to jump into the room, and the safety of passengers can be improved.

[Brief description of drawings]

FIG. 1 is a view showing a suspension subframe made of an aluminum alloy according to an embodiment of the present invention, in which (a) is a top view and (b) is a side view.

2 is a cross-sectional view taken along the line AA in FIG.

FIG. 3 is an exploded view showing a member located on an upper side in a suspension subframe made of an aluminum alloy according to an embodiment of the present invention.

FIG. 4 is an exploded view showing a member located below in a suspension subframe made of an aluminum alloy according to an embodiment of the present invention.

5A and 5B are views showing a structure of a conventional steel suspension subframe, in which FIG. 5A is a top view and FIG. 5B is a side view.

6A to 6C are schematic diagrams showing modifications of subframes.

[Explanation of symbols]

1C; central member 1CT; central upper member 1CB; lower central member 1R; right member 1RT; upper right member 1RB; lower right member 1L; left member 1LT; upper left member 1LB; lower left member 2; Weld beads 3T; Upper back plate 3B; lower backing plate 4; joining surface 5: Weld line 10; Suspension subframe

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeki Yabe             Kanagawa Prefecture Fujisawa City Miyamae character Urakawachi 100-1 share             Ceremony Company Kobe Steel Fujisawa Office F term (reference) 3D003 AA04 AA12 BB01 CA18 DA29

Claims (3)

[Claims] 1. An aluminum alloy subframe to which a front wheel of an automobile is attached, wherein a tubular first aluminum alloy member extending in a width direction of the automobile and one end portion of the first aluminum alloy member are provided. A second tubular member joined by welding and extending in the longitudinal direction of the automobile.
And a tubular third aluminum alloy member that is joined to the other end of the first aluminum alloy member by welding and extends in the longitudinal direction of the automobile. Subframe made of aluminum alloy. 2. An aluminum alloy backing plate fixed to an inner surface of the joint portion between the first and second aluminum alloy members and the joint portion between the first and third aluminum alloy members. The aluminum alloy subframe according to claim 1, wherein the subframe is made of aluminum alloy. 3. The joint surfaces of the first and second aluminum alloy members and the joint surfaces of the first and third aluminum alloy members are substantially parallel to the longitudinal direction of the automobile. The aluminum alloy subframe according to claim 1 or 2.