JP2000126832A - Production of vehicle body frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a vehicle body frame capable of preventing a difference in level from forming in an external appearance at a low cost and preferably providing the regions having partially different rigidity. SOLUTION: Part of a first hollow shape material is reduced in diameter along its outer circumference by electromagnetic forming. The first hollow shape material is cut in a reduced region to obtain a hollow shape material 1a. Successively, the hollow shape material 1a is fitted into in a second hollow shape material 2, the outside face shape of the one end of which is coincided to the outside face shape at the boundary between the reduced region of the hollow shape material 1a and the region not reduced and having a thickness equal to a reduced quantity. The boundary of the hollow shape material 1a and the end part of the second hollow shape material 2 are joined, the reinforcement formed by this joining is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a body frame used for a body of an automobile or the like, and more particularly, to a method for manufacturing a body frame capable of preventing formation of a step in appearance.

[0002]

2. Description of the Related Art A member used for an automobile or the like is required to have rigidity corresponding to a portion where the member is used. For example, Japanese Patent Application Laid-Open No.
Japanese Patent Publication No. 277791 proposes a deck cross member in which a large-diameter pipe and a small-diameter pipe are combined. FIG.
FIG. 1 is a partial cross-sectional view showing a deck cross member described in Japanese Patent Application Laid-Open No. 9-277961.

[0003] The deck cross member described in Japanese Patent Application Laid-Open No. 9-277961 is composed of a small-diameter pipe 11 and a large-diameter pipe 12 having a diameter larger than the small-diameter pipe 11. One end of the small diameter pipe 11 is expanded so that its inner diameter is equal to the outer diameter of the large diameter pipe 12. A large-diameter pipe 12 is press-fitted and inserted into an end of the small-diameter pipe 11. The distal end of the small-diameter pipe 11 and the outer surface of the large-diameter pipe 12 are fillet-welded to form the weld metal 1.
3 are formed.

In the thus constructed deck cross member, the rigidity of the large-diameter pipe 12 is increased, so that
The large-diameter pipe 12 is disposed on the driver's seat side where the heavy steering column is attached.

[0005] Also, when the body of an automobile is made of a press-formed product, there are parts that require partially different rigidity. For example, different characteristics such as rigidity are required between the roof rail and the front pillar and the rear pillar. For this reason, it is important to dispose members having different thicknesses, materials, and the like in the right places at the right places. FIG. 9 is a schematic view showing a joint between the roof rail and the rear pillar. As shown in FIG. 9, the roof rails 14, the rear pillars 15, the front pillars (not shown), and the like are different from the deck cross members and are exposed outside the vehicle body. Therefore, these joints 16 are required to have a good appearance. For this reason, in joining a plate material such as a press-formed product, a method of providing a step at an end of one plate material has been adopted. FIG. 10 is a schematic diagram showing a plate member provided with a step. FIG.
11A and 11B are schematic views showing a joining method using the plate material shown in FIG. 10 in the order of steps.

When a plate material is used in a joint where a good appearance is required, as shown in FIG.
Is used in which a step is formed at the end by the thickness of the plate. Then, as shown in FIG.
The other plate 18 is placed on the step 7, and the curved portion of the step and the end of the plate 18 are welded and joined to form the extra bank 19. Next, as shown in FIG. 11B, the excess bank 19 is removed to flatten the joint. Such a joining method is described in, for example, JP-A-9-225684.

[0007]

However, when an automobile body is to be assembled not as a press-formed product but as a frame structure using a hollow pipe-shaped material, it is described in Japanese Patent Application Laid-Open No. 9-277961. When the above-mentioned joining method is applied, there is a problem that a step is generated in the appearance as shown in FIG. For this reason, a portion to which this method can be applied is limited to a portion having no problem even if a step is generated in the appearance. That is, the present invention cannot be applied to a portion where the appearance is important such as a joint between the roof rail and the front pillar or the rear pillar.

Further, it is extremely difficult to provide a step in the hollow profile as in the case of joining the plate members described above. Therefore, it is not possible to apply a method of providing a step in the welding connection of the hollow profile.

Therefore, when assembling an automobile body as a frame structure using a hollow pipe-shaped member, the frame is used as a frame member so as not to expose the frame to the outside of the automobile. Either the panel is arranged so as to be covered by the molded panel material, or the monocoque structure and the frame structure are mixed in one vehicle body, and the molded panel is arranged in a portion where appearance is regarded as important.

However, such a structure is extremely complicated and causes an increase in design cost. Furthermore, since an aluminum extruded profile (pipe-shaped hollow profile) having excellent productivity cannot be applied consistently, the production cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is intended for a vehicle body capable of preventing the formation of a step in appearance at low cost and preferably providing a region having partially different rigidity. An object of the present invention is to provide a method for manufacturing a frame.

[0012]

According to the present invention, there is provided a method of manufacturing a body frame, comprising: a step of contracting a part of a first hollow member by electromagnetic molding; and a step of contracting the first hollow member. The outer surface shape at the boundary between the closed region and the non-contracted region and the outer surface shape at one end coincide with each other, and the second hollow member has the same thickness as the contracted amount of the first hollow profile. Fitting the first hollow profile into the hollow profile of
Joining the boundary of the hollow profile to the end of the second hollow profile.

In the present invention, since the first hollow member is contracted by electromagnetic molding, a desired amount of contraction can be easily performed. Then, the outer surface shape at the boundary between the contracted region and the non-contracted region and the outer surface shape at one end coincide with each other, and the inside of the second hollow member having the same thickness as the contracted amount is formed. , A uniform appearance is obtained in a region other than the vicinity of the boundary. Therefore, it is possible to prevent the formation of a step in the appearance when the two hollow members are connected.

[0014] In addition, an extra bank formed by the joining may be removed. After joining the boundary and the end of the second hollow profile, the excess is removed to further flatten the vicinity of the joint. Therefore, formation of a step can be more reliably prevented.

[0015] The first hollow member and the second hollow member may have different rigidities. By using hollow profiles having different stiffnesses, it is possible to manufacture a body frame in which regions having partially different stiffnesses are provided.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a vehicle body frame according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIGS. 1A and 1B are schematic views showing a method of manufacturing a vehicle body frame according to an embodiment of the present invention in the order of steps. In the present embodiment, aluminum or aluminum alloy having different rigidities (hereinafter, aluminum and aluminum alloy are collectively referred to as aluminum).
A frame for a vehicle body is formed using two pipe-shaped (cylindrical) aluminum shapes having outer diameters of, for example, 50 mm and different wall thicknesses. The thickness of one aluminum profile is, for example, 1 mm, and the thickness of the other aluminum profile is, for example, 2 mm.

First, as shown in FIG.
1 mm of a pipe-shaped first aluminum profile 1 is installed in the electromagnetic forming device 3. The electromagnetic molding device 3 is provided with a coil 3a connected to a power supply.
A magnetic flux concentrator (shaper) 3b for concentrating the magnetic flux generated from the coil 3a is provided inside the inside. The length of the region of the magnetic flux concentrator 3b facing the aluminum profile 1 is, for example, 60 mm. FIG. 2 is a schematic view showing processing by an electromagnetic forming device. When a current flows from the power supply to the coil 3a, the magnetic flux generated from the coil 3a concentrates on the surface of the magnetic flux concentrator 3b facing the aluminum profile 1. Then, a force for expanding the interval between the aluminum profile 1 and the magnetic flux concentrator 3b, that is, a force for contracting the aluminum profile 1 acts on the aluminum profile 1.

In this embodiment, a current is applied to the coil 3a so that only the area of the aluminum section 1 facing the magnetic flux concentrator 3b is 2 mm, as shown in FIG.
Only to contract. The amount of this tube shrinkage is
Is equal to the thickness of the other aluminum section to be joined. In FIG. 1B, the capacitors, switches, and the like shown in FIG. 1A are omitted.

FIG. 3 is a view showing a method of manufacturing the vehicle body frame according to the embodiment of the present invention, and is a schematic view showing a step subsequent to the step shown in FIG. After the aluminum profile 1 is contracted, the aluminum profile 1 is cut so that a cross section orthogonal to the tube axis direction is formed in the region where the tube is contracted. In one of the cut pieces cut in this way, the length of the contracted region is 30 mm or more. For example, in one profile, the length of the curved portion 4 due to the step in the tube axis direction is 3 to 5 mm, and the length of the parallel portion 5 parallel to the portion not contracted is 30 mm. In the present embodiment, an aluminum profile 1a having a length of the constricted region of 30 mm or more is used in a later step.

FIG. 4A is a view showing a method of manufacturing the vehicle body frame according to the embodiment of the present invention, and is a schematic view showing a step subsequent to the step shown in FIG. 3, and FIG. A-) in
It is sectional drawing in the A line. After the cutting of the aluminum profile 1, the region of the aluminum profile 1 a in which the tube was contracted was, as shown in FIG. 4 (a), 2 mm thick and the same outer diameter as the aluminum profile 1 (50 mm). ) Is fitted into the aluminum profile 2. Since the amount of contraction of the aluminum profile 1a is 2 mm and the thickness of the aluminum profile 2 is also 2 mm, except for the curved portion 4 of the aluminum profile 1a,
The appearance shape matches in all areas.

Thereafter, the curved portion 4 of the aluminum profile 1a
(Gap) welding or brazing is performed. The joint is flattened by removing the excess build-up formed by the welding or brazing.

In the body frame manufactured as described above, the thickness of the aluminum profile 1a is 1 mm, and the thickness of the aluminum profile 2 is 2 mm. high. Further, no step is formed on the appearance. Therefore, the present invention can be applied to a vehicle body frame that requires partially different rigidity and good appearance.

In the above-described embodiment, the cylindrical aluminum members 1 and 2 are used, but the shape of the hollow member is not limited to this. FIG. 5 is a sectional view showing a flat cylindrical body frame. For example,
The hollow profile may be flat cylindrical. Also in this case, one end of one hollow profile 6 is contracted by the thickness of the other hollow profile 7 by electromagnetic molding. In addition, for example, the major axis length in a cross section perpendicular to the tube axis of the hollow profiles 6 and 7 is 100 mm, and the minor axis length is 60 mm.

Further, the contraction by electromagnetic forming may be performed not in the direction perpendicular to the tube axis but in a direction inclined from the direction perpendicular to the tube axis. In this case, the shape of the portion of the magnetic flux concentrator facing the hollow member may be changed. FIG. 6 is a schematic diagram showing a magnetic flux concentrator. FIG. 7 is a schematic diagram showing a hollow member that has been contracted using the magnetic flux concentrator shown in FIG.
Inside the magnetic flux concentrator 8, a convex portion 8a is provided along a direction inclined from the central axis. This convex portion 8a
Is a surface facing the hollow shape member to be electromagnetically formed. Then, the shape of the protruding portion 8a is transferred to the hollow member 9 contracted by using this magnetic flux concentrator. The cutting of the hollow section 9 is performed along the reduced tube region.

Further, in the above-described embodiment, the materials of the hollow sections to be joined are the same, but these materials may be different. Further, the hollow shape member to be electromagnetically formed may be thicker.

Furthermore, a core may be arranged in one end of the hollow profile and the end of the hollow profile may be contracted by electromagnetic molding. In the case where the tube is cut at the center portion of the profile and cut therefrom as in the above-described embodiment, there is an advantage that two profiles whose ends are contracted can be produced at the same time. In the case where one end of the hollow profile is contracted by using the method, there is an advantage that the cutting step can be omitted. In this case, it is desirable that the core has a tapered shape or that the outer diameter of the core can be changed so that the core can be easily removed from the profile after the contraction.

[0027]

As described in detail above, according to the present invention,
The first hollow profile is contracted by electromagnetic molding, and the outer surface shape at the boundary between the contracted region and the non-contracted region of the first hollow profile and the outer surface at one end. Since the second hollow profile having the same thickness and the same thickness as the reduced volume of the first hollow profile is used, it is possible to prevent the formation of steps in the appearance at a low cost and to flatten it. It is possible to easily manufacture a vehicle body frame having the outer side surface. Furthermore, by removing the extra height formed by joining,
The formation of a step can be more reliably prevented. Also,
By using the first hollow member and the second hollow member having different stiffness, it is possible to manufacture a body frame having a region having partially different stiffness. Furthermore,
If aluminum or aluminum alloy profiles having excellent productivity are used consistently for the hollow profile in the present invention, there is no need to use duplicate press-formed products for the vehicle body, so that manufacturing costs can be further reduced. it can.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic views showing a method of manufacturing a vehicle body frame according to an embodiment of the present invention in the order of steps.

FIG. 2 is a schematic view showing processing by an electromagnetic forming device.

3 is a view showing a method of manufacturing the vehicle body frame according to the embodiment of the present invention, and is a schematic view showing a step subsequent to the step shown in FIG. 1. FIG.

4A is a view showing a method of manufacturing a vehicle body frame according to an embodiment of the present invention, and is a schematic view showing a step subsequent to the step shown in FIG. 3; FIG. AA in)
It is sectional drawing in a line.

FIG. 5 is a sectional view showing a flat cylindrical body frame.

FIG. 6 is a schematic diagram showing a magnetic flux concentrator.

FIG. 7 is a schematic diagram showing a hollow section that has been contracted using the magnetic flux concentrator shown in FIG. 6;

FIG. 8 is a partial cross-sectional view showing a deck cross member described in Japanese Patent Application Laid-Open No. 9-277961.

FIG. 9 is a schematic diagram showing a joint between a roof rail and a rear pillar.

FIG. 10 is a schematic view showing a plate member provided with a step.

FIGS. 11A and 11B are schematic views showing a joining method using the plate material shown in FIG. 10 in the order of steps.

[Explanation of symbols]

 1, 1a, 2, 6, 7, 9; aluminum profile 3; electromagnetic forming device 3a; coil 3b, 8; magnetic flux concentrator 4: bending portion 5; parallel portion 8a; convex portion 11; small diameter pipe 12; Diameter pipe 13; weld metal 14; roof rail 15; rear pillar 16; joints 17, 18; plate 19;

Claims (3)

[Claims] 1. A step of contracting a part of a first hollow profile by electromagnetic molding, and an outer surface shape at a boundary between a contracted region and a non-contracted region of the first hollow profile. The first hollow profile is fitted into a second hollow profile having the same outer wall shape as one end and the same thickness as the amount of the first hollow profile contracted. And a step of joining the boundary of the first hollow profile and the end of the second hollow profile to each other. 2. The method for manufacturing a vehicle body frame according to claim 1, further comprising a step of removing an extra bank formed by the joining. 3. The first hollow section and the second hollow section have different stiffness.
3. The method for manufacturing a body frame according to claim 1.