JP3672408B2 - Manufacturing method of frame-like structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for manufacturing a frame-like structure.
[0002]
[Prior art]
FIG. 16 is a perspective view of a typical frame-shaped structure. This frame-shaped structure 100 is an aluminum sash frame, and includes an upper frame 102 including a stepped portion 101, a lower frame 103, a left frame 104, and a right frame 105. Are combined in a mouth shape.
17A to 17C are manufacturing process diagrams of a conventional frame-like structure.
In (a), the long aluminum material is cut into a predetermined length to obtain the upper frame 102, the lower frame 103, the left frame 104, and the right frame 105. A long aluminum material having a fairly complicated cross-section (for example, a square cross-section including the stepped portion 101) can be easily manufactured by extrusion, and this may be used as a raw material.
In (b), the upper frame 102, the lower frame 103, the left frame 104, and the right frame 105 are combined into a mouth shape.
In (c), the frames are connected by welding. 106 (... indicates a plurality. The same applies hereinafter) is a bead.
[0003]
[Problems to be solved by the invention]
The frame-like structure 100 has no problem as long as the overall shape is simple and the cross section is uniform, but it is not suitable for the case where the cross-sectional shape changes from place to place.
[0004]
By the way, the door mounting frame for mounting the door of the vehicle includes a curved portion, and many of them are curved three-dimensionally, and the sectional shape changes for each part. . Therefore, a frame-like structure having a complicated shape must be subjected to press molding.
[0005]
[Means for Solving the Problems]
In the process of researching an alternative to the conventional technique of manufacturing a frame-like structure by combining spot-pressed and bent materials from flat plates, the present inventors have made complex aluminum alloy round pipes as materials. We succeeded in producing a frame-shaped structure.
Specifically, the method of claim 1 selects the thickness of a round pipe made of aluminum alloy as a base material from the product thickness and elongation rate, and approximates the selected pipe to the product shape by a vendor. A forming step for plastic processing to a shape, a joining step for joining the forming material to form a hoop, and a step for introducing the forming material into the cavity of a blow mold having a cavity for defining the outer peripheral surface of the product, Heating the forming material contained in the mold to a temperature above the softening point and below the melting point, and expanding the heated hollow forming material by blowing a high-pressure fluid and pressing the outer peripheral surface against the outer peripheral surface of the cavity A frame-like structure comprising a blow molding process is manufactured.
[0006]
Since the thickness of the base material is selected in consideration of the elongation rate, the thickness of the finished product becomes a desired one and the necessary rigidity can be maintained.
Since it is basically not a welded structure, there is very little beading and the appearance of the product is good.
Since trimming is not required, the yield is good and the cost can be reduced.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. The frame-like structure will be described using a vehicle door mounting frame as an example.
FIG. 1 is an external view of a door frame of a vehicle manufactured by the method of the present invention. The door mounting frame 1 includes an upper frame portion 2, a front inclined frame portion 3, a front vertical frame portion 4, a lower frame portion 5, and a rear inclined frame. It is a hollow annular body composed of a part 6 and a rear vertical frame part 7.
FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1. The front inclined frame 3 has a side surface 3a and a rear surface 3b which are straight surfaces, and has step portions 3e and 3f on the vehicle outer surface 3c and the front surface 3d.
3 is a cross-sectional view taken along line 3-3 of FIG. 1, and the lower frame portion 5 has a vertically long rectangular cross section, and has step portions 5c and 5d at the front portion of the vehicle interior side surface 5a and the rear portion of the vehicle outer surface 5b. .
4 is a cross-sectional view taken along line 4-4 of FIG. 1, and the rear inclined frame portion 6 has tapered surfaces 6a and 6b and a step portion 6c.
FIG. 5 is a sectional view taken along line 5-5 in FIG. 1, and the rear vertical frame portion 7 has step portions 7c and 7d at the rear portion of the indoor surface 7a and at the front portion of the vehicle outer surface 7b.
Thus, the door mounting frame 1 has a different cross-sectional shape for each part.
[0008]
FIG. 6 is an explanatory view of a blow molding die according to the present invention. The blow molding die 10 includes a lower die 11 as a fixed die and an upper die 12 as a movable die, and a groove 13 and a rocket are formed in the lower die 11. Pins 14, 14 and upper mold 12 have grooves 15, pin receiving holes 16, 16 and blow pipe insertion holes 17, upper mold 12 is stacked on lower mold 11, and grooves 13 and 15 are combined to blow. A cavity is formed as a molding space for molding.
[0009]
FIG. 7 is a cross-sectional view of the cavity of the blow mold, and the figure is for obtaining the cross section of FIG. 2. The groove 15 of the upper mold 12 is overlapped with the groove 13 of the lower mold 11, and if necessary, Then, the required cavity 19 is formed by setting the standing mold 18. The contour of the cavity 19 matches the outer peripheral surface of the cross section of FIG. Although the shape of the cavity 19 is different for each place, the description is omitted.
[0010]
FIG. 8 is a principle diagram of the blow equipment and heating equipment according to the present invention. In the heating furnace 20, a heat insulating material 22 is lined on a furnace shell 21, heaters 23, 23 are attached to a furnace wall, and a pier 25, 25 and 25 and a temperature sensor 26 (for example, a thermocouple) are attached, a temperature signal of the temperature sensor 26 is received by the furnace temperature control unit 27, and the furnace temperature control unit 27 controls the temperature so that the furnace temperature becomes a predetermined value. Reference numeral 28 denotes a power supply control unit. The heating temperature is 480 to 550 ° C.
The blow equipment 30 includes a compressor 31, a pressure adjustment valve 32, a heat-resistant flexible tube 33, and the like, and supplies compressed air to the mold 10. In this example, the pressurizing medium is air, but if oxidation is disliked, an inert gas such as nitrogen gas is used, and the compressor 31 is changed to a gas cylinder.
[0011]
Next, a method for manufacturing the door mounting frame 1 using the equipment described above will be described.
FIGS. 9A and 9B are diagrams for selecting the thickness according to the present invention.
(A) shows the round pipe 41 made from aluminum alloy which selected thickness t1 from product thickness and elongation rate.
(B) is the product 40, and the thickness of the product 40 is t2.
If the thickness center circumference of the product 40 is L2, and the thickness center circumference of the round pipe 41 as the base material is L1, the formula of L1 × t1 = L2 × t2 is generally established, and the thickness t1 of the base material Can be calculated by (L2 × t2) / L1. For example, if L1 of a round pipe with an outer diameter of 48 mm is 150 mm, L2 of the product is 370 mm, and the wall thickness t2 of the product is 2.0 mm, t1 is about 4.9 mm. Therefore, a round pipe 41 having a thickness of 5.0 mm may be selected. Here, selection includes selecting from a group of round pipes having different wall thicknesses manufactured in advance and manufacturing a pipe having a desired wall thickness each time.
[0012]
10A to 10D are manufacturing process diagrams (previous term) of the door mounting frame according to the present invention.
{Cutting step} In (a), a predetermined length of the aluminum alloy round pipe 41 is cut out from the selected Al-Mg aluminum alloy round pipe.
{Forming step} In step (b), bending is performed by the vendor 42.
(C) shows the step of making the round pipe 41 into an elliptical cross-section pipe by pressing, and (d) shows the step of reducing the diameter of the round pipe 41 by drawing, and these processings are added as necessary.
[0013]
11A to 11C are joining process diagrams (first embodiment) between pipes having different thicknesses.
(A) shows a round pipe 41A having a wall thickness t1 with a groove at the pipe end, and a round pipe 41B having a thin wall thickness t4 formed by bouncing the pipe end.
(B) shows a cross section after the round pipes 41A and 41B are butted together and butt welded from the outside. 44 is a bead and 46 is a surplus. Since pipes having the same wall thickness are basically joined together, welding is easy and welding defects are not easily generated.
(C) is obtained by removing the surplus 46 by cutting with a cutting tool or grinding with a grinder, and making the outer surface of the bead 44 flush with the outer periphery of the pipes 41A and 41B. By making it flush, the next blow molding becomes easy.
[0014]
FIGS. 12A and 12B are manufacturing process diagrams (mid-term) of the door mounting frame according to the present invention.
(A) shows the state which joined both ends of the pipe by which bending was carried out by welding to make a hoop (wheel), and the pressurization pipe 43 was attached to this hoop. 44 is a bead. The resulting forming material 45 exhibits a contour that is substantially the same as the product shape.
In (b), the forming material 45 is placed in the cavity 19 of the blow molding die 10 and selected from the temperature range from 480 to 550 ° C. above the softening point (less than the melting point) in the heating furnace 20 shown in FIG. And then blown by sending a pressurized fluid.
[0015]
FIGS. 13A to 13F are manufacturing process diagrams (late stage) of the door mounting frame according to the present invention, that is, blow molding process diagrams.
In (a), the forming material 45A formed into an ellipse is accommodated in the cavity 19 of the mold, and this is blown warm.
(B) shows the molded product W1 after blow molding (a part of the door mounting frame 1), and the outer peripheral surface of the molded product W1 is defined by the outer peripheral surface of the cavity 19 of the mold. Thus, the cross section shown in FIG. 2 can be formed.
In (c), the forming material 45B is accommodated in the cavity 19 of the mold, and this is warm blow molded.
(D) shows the molded product W2 after blow molding, and the cross section shown in FIG. 5 can be molded.
In (e), the forming material 45C is housed in the cavity 19 of the mold, and this is blown warm.
(F) shows the molded product W3 after blow molding, and the cross section shown in FIG. 3 can be molded.
As described above, when the aluminum alloy round pipe cannot be stored in the cavity as it is, it is ovalized or reduced in diameter.
[0016]
The door mounting frame 1 of FIG. 1 having the cross section of FIGS. 2 to 5 can be manufactured by the above warm blow molding.
[0017]
Note that the order of the processing steps described in FIGS. 10A to 10D can be changed, and may be, for example, (a) → (c) and / or (d) → (b). Alternatively, FIG. 10 (a) → (b) → FIG. 12 (a) → FIG. 9 (c), (d) may be used.
Furthermore, although the door mounting frame has been described as an example in the present embodiment, the frame-like structure of the present invention is not limited to this, and can be applied to a broad frame such as a vehicle frame, a building frame, or a decoration frame.
[0018]
14 (a) and 14 (b) are diagrams of a joining process (second embodiment) between pipes having different thicknesses.
(A) shows a round pipe 41A having a wall thickness t3 with a groove at the pipe end, and a round pipe 41B having a thick wall thickness t4 that is thinned only at the tip by boring the pipe end in a tapered shape. .
(B) After the round pipes 41A and 41B are butted together and butt welded from the outside, the surplus is removed by cutting with a cutting tool or grinding with a grinder, and the outer surface of the bead 44 faces the outer circumference of the pipes 41A and 41B It is one.
Compared to the first embodiment, skill is required for the taper hole processing, but the strength is advantageous because the wall thickness gradually changes.
[0019]
FIGS. 15 (a) and 15 (b) are joining process diagrams (third embodiment) of pipes having different thicknesses.
(A) shows a round pipe 41A having a wall thickness t3 with a groove at the end of the pipe, and a round pipe 41B having a thin wall thickness t4 with a thin wall thickness t3 only at the tip by cutting the outer surface of the pipe end into a tapered shape. .
(B) After the round pipes 41A and 41B are butted together and butt welded from the outside, the surplus is removed by cutting with a cutting tool or grinding with a grinder, and the outer surface of the bead 44 is flush with the outer periphery of the pipe 41A. It is a thing.
Compared to the first embodiment, skill is required for the taper hole processing, but the strength is advantageous because the wall thickness gradually changes.
[0020]
【The invention's effect】
The present invention exhibits the following effects by the above configuration.
The method of claim 1 includes a step of selecting a thickness of an aluminum alloy round pipe as a base material, a step of forming the selected pipe, a joining step of joining the forming material into a hoop, and a forming material. It consists of a step of putting into a mold, a step of heating a forming material housed in the die, and a step of blow molding a hollow forming material.
[0021]
Since the thickness of the base material is selected in consideration of the elongation rate, the thickness of the finished product becomes a desired one and the necessary rigidity can be maintained.
Since it is basically not a welded structure, there is very little beading and the appearance of the product is good. In addition, since trimming is not required, the yield is good and the cost can be reduced.
[Brief description of the drawings]
1 is an external view of a vehicle door frame manufactured by the method of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. FIG. 5 is a sectional view taken along the line 5-5 in FIG. 1. FIG. 6 is an explanatory view of the blow molding die according to the present invention. FIG. 7 is a sectional view of the cavity of the blow molding die. [Fig. 9] Principle diagram of blow equipment and heating equipment according to the present invention [Fig. 9] Diagram for selecting thickness according to the present invention [Fig. 10] Manufacturing process diagram of door mounting frame according to the present invention (previous term)
FIG. 11 is a process diagram for joining pipes having different thicknesses (first embodiment).
FIG. 12 is a manufacturing process diagram of a door mounting frame according to the present invention (mid-term)
FIG. 13 is a manufacturing process diagram of the door mounting frame according to the present invention (late stage).
FIG. 14 is a process diagram for joining pipes having different thicknesses (second embodiment).
FIG. 15 is a process diagram for joining pipes having different thicknesses (third embodiment).
FIG. 16 is a perspective view of a typical frame structure. FIG. 17 is a manufacturing process diagram of a conventional frame structure.
DESCRIPTION OF SYMBOLS 1 ... Frame-shaped structure (door mounting frame), 10 ... Blow mold, 19 ... Cavity, 20 ... Heating furnace, 30 ... Blow equipment, 41, 41A, 41B ... Aluminum alloy round pipe (round pipe), 42 ... Vendor, 45 ... Forming material, t1-t4 ... Thickness of round pipe.

Claims (1)

The process of selecting the thickness of a round pipe made of aluminum alloy as a base material from the product thickness and elongation rate, the process of cutting the selected pipe into a predetermined length, and approximating this pipe to the product shape by a vendor Forming step of plastic working to the shape formed, joining step of joining the forming material to form a hoop, and step of introducing the forming material into the cavity of the blow molding die having a cavity defining the outer peripheral surface of the product; A step of heating the forming material contained in the mold to a temperature not lower than the softening point and lower than the melting point; The manufacturing method of the frame-shaped structure which consists of a blow molding process to press.

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