JP2003200227A - Hydroform processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydroforming method capable of ensuring sufficient sealability at an inexpensive configuration by using a stock seam-welded overlapped plates. <P>SOLUTION: A projecting part 6 is pressed in at least one surface of overlapped plates, a hole 7 is formed in a top part of the projecting part, a liquid filling piece 8 is disposed so as to fill the hole and a space on the recessed surface side of the projecting part, another plate overlaps on the side with the piece disposed, the entire periphery of an edge of an area 10 to fill the liquid is seam-welded 2, and when the stock is held by dies 11 and 11A, a circumscribed part of the plate with the piece and a peripheral part thereof are held by the dies. <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 a hydroforming method, and more particularly to a hydroforming method which can be preferably used when manufacturing parts having a complicated shape such as automobile parts.

[0002]

2. Description of the Related Art From the viewpoint of reducing the weight of a vehicle body, parts (HF parts) manufactured by hydroforming (HF processing) are adopted as parts of vehicle undercarriage such as suspension arms and vehicle structural parts such as frames. There is a trend.
In HF processing, a metal pipe such as an electric resistance welded pipe is usually sandwiched between molds, a liquid is press-fitted into the pipes, and bulge molding is performed to obtain an HF component having an outer surface shape that follows the inner surface shape of the mold. Try to.

The inner surface of the mold has a wide variety of shapes such as a three-dimensionally bent shape and a branched shape corresponding to various shapes of automobile parts. Since an ordinary metal tube has a straight shape, it cannot be loaded into a bent inner surface mold as it is. Therefore, in HF processing using a metal tube as a raw material, preforming (preforming) processing such as pre-bending (pre-bending) or pre-pressing (pre-pressing) is performed to form the metal tube into a shape that can be inserted into a mold. .

However, when a metal tube is preformed into a complicated shape, the amount of processing becomes large, resulting in uneven thickness and deterioration of ductility due to work hardening. If the wall thickness is uneven, the thin-walled portion is preferentially deformed during HF processing, which tends to cause defective molding. Further, if the ductility is greatly deteriorated, cracks will be generated with a relatively small amount of deformation during HF processing. Therefore, there is a problem in that the HF processing amount (bulge deformation amount) cannot be set to a very large value.

This problem is solved by using, for example, Japanese Patent Application Laid-Open Nos. 9-029329 and 20 instead of a metal tube as a material for HF processing.
This can be solved by using a composite plate material as disclosed in Japanese Patent Publication No. 00-225114, which is formed by stacking two or more metal plate materials and stitching and welding their edges. According to this, without adding a large amount of processing such as preforming of a metal tube, the composite plate material can be formed into a shape that can be loaded into a mold as it is or by cutting or lightly deforming it. .

[0006]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
In the HF processing method disclosed in Japanese Patent Application Laid-Open No. 029329 and Japanese Patent Application Laid-Open No. 2000-225114, there is a problem in the method of press-fitting a liquid between the superposed surfaces of the plate materials forming the material. This is because, in Japanese Patent Laid-Open No. 9-029329, a half-side injection port is formed outside the product sampling area of the plate material, and the plate materials are stacked so that the half-side injection ports face each other to form the injection port. The edge portion of the mold bulge forming target area is sewn and welded while leaving the inlet, the injection nozzle is fitted into the injection port, and the liquid is press-fitted from the injection nozzle. Also,
In Japanese Patent Laid-Open No. 2000-225114, plate materials are overlapped with each other, and one or two or more locations outside the product sampling area are left as slit-shaped openings, and the edges of the mold bulge molding target area are sewn and welded, and the slit-shaped openings By inserting the mouth-expanding jig and the injection nozzle, the injection port is formed and the injection nozzle is inserted at the same time.
Liquid is press-fitted from the injection nozzle. As disclosed in these publications, the injection nozzle usually has a circular cross section. Further, the portion outside the product sampling area is cut off after the HF processing.

However, in the injection port formed in this manner, as shown in FIG. 3, for example, a concave triangle having a joint portion of the suture weld 2 as one apex on both sides of the injection nozzle 4 fitted in the injection port 3. Since the gap 5 of the shape is created, the sealing performance is deteriorated, and the desired fluid pressure may not be reached in the material body formed between the overlapping surfaces of the plate materials 1 and 1A, and the desired HF component shape may not be obtained. is there.

This gap can be closed by welding, but since the injection nozzle is welded to the plate material, it is difficult to collect and reuse the injection nozzle, and the cost of holding the injection nozzle increases. Further, according to the method disclosed in Japanese Patent Laid-Open No. 2000-225114, in which an outer surface restraint jig is used and the lip portion of the inlet is clamped between the outer nozzle and the injecting nozzle, the sealability can be improved. But this way,
Since a special outer surface restraint jig and a specially shaped inner surface packing are used, the manufacturing cost is high, and it is difficult to secure sufficient sealing performance when the required fluid pressure is above a certain level (for example, above 100 MPa). There is a problem of becoming.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a hydroforming method capable of ensuring a sufficient sealability with an inexpensive structure by using a material in which plate materials are superposed and sewn and welded. is there.

[0010]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a liquid injection port is provided in the surface of a plate material, and a gap around a liquid injection metal fitting fitted to the liquid injection port is formed in a mold. The present invention was made based on the finding that the above-mentioned object can be achieved by using the mold clamping force of (1) to block. That is, the present invention is a hydroform processing method in which two or more metal plate materials are superposed and sewn together and sandwiched by a pair of molds, and a liquid is press-fitted between the overlapping surfaces to form a mold bulge. Prior to superimposing, a convex portion is press-formed in the surface of at least one of the plate materials, and then a hole is formed at the top of the convex portion, and liquid injection is performed so as to fill the opening and the concave side space of the convex portion. When the metal fittings are arranged, another plate material is superposed on the side where the metal fittings are arranged, the entire circumference of the edge of the region where the liquid is press-fitted is stitched and welded, and when the material is clamped by the mold, the plate material is used by the same mold. The hydroforming method is characterized in that the circumscribing portion with the metal fitting and the peripheral portion thereof are clamped.

In the present invention, it is preferable that the inclination angle of the inscribed surface of the metal fitting to the convex portion is larger than the inclination angle of the circumscribed surface of the mold to the convex portion. Further, in the present invention,
When pressing the circumscribing portion of the plate material with the metal fitting and its peripheral portion with the mold, a packing is fitted on the convex side of the metal fitting, and the packing is used around the opening of the convex portion with the mold. Pressing on the portion, or a screw is provided on the outer surface of the convex portion convex side portion of the metal fitting, and when the outer peripheral portion of the plate material with the metal fitting and its peripheral portion are pressed by the mold, the metal fitting After fitting the packing to the convex surface side portion, it is preferable that the packing is pressed to the peripheral portion of the opening of the convex portion by screwing a nut onto the screw and tightening the nut.

[0012]

1 and 2 are explanatory views showing one of the embodiments of the present invention. In this example, a case is shown in which two metal plates are superposed and sewn together. As the metal plate material, a steel plate such as a hot-rolled steel plate or a cold-rolled steel plate, a copper plate, an aluminum plate, or the like can be appropriately used. The suture welding can be performed by an appropriate method such as laser welding or plasma welding.

In the present invention, as shown in FIGS. 1A and 1B, at least one plate 6 of the plate material 1 is press-formed with a convex portion 6 before the superposition, and an opening is formed at the top of the convex portion 6. Drill 7 It is desirable that the portion where the convex portion 6 is press-molded is located in a non-product sampling area which is to be cut off after the HF processing. Then, as shown in FIG. 1C and FIG.
A conical-shaped metal fitting (metal fitting for liquid injection) 8 is arranged so as to fill the space on the concave side of the plate, and another plate material is provided on the side where the metal fitting 8 is arranged.
Stack 1A. It is preferable that the liquid injection metal fitting 8 is provided with a liquid passage 9 inside a hard material such as tool steel or cemented carbide. Next, as shown in FIG. 1E, suture welding 2 is applied to the entire circumference of the edge of the region 10 into which the liquid is press-fitted. The material is thus formed.

When this material is sandwiched by a pair of molds, as shown in FIG. 2 (a), for example, an upper mold 11 and a lower mold are used.
With 11A, the circumscribing portion of the plate materials 1 and 1A with the metal fitting 8 and its peripheral portion are clamped. The press-fitting liquid is, for example, an upper mold.
The liquid is fed to the liquid passage 9 of the metal fitting 8 through the die through hole 12 provided in 11. In the present invention, by having such a configuration,
The inner peripheral surface of the convex portion 6 closely adheres to the outer peripheral surface of the metal fitting 8,
A portion corresponding to the gap 5 in FIG. 3 (c) is not formed, and the edge of the region 10 of the opening 7 into which the liquid is press-fitted is sewn and welded over the entire circumference, so that a sufficient sealing property is obtained. Can be secured. Since the metal fitting 8 is not welded to the plate material 1, it can be easily recovered and reused.
Since no special tool such as the outer surface restraint jig disclosed in Japanese Patent No. 225114 is required, HF processing can be performed at low cost.

Further, in the present invention, as shown in FIG. 2B, for example, the inclination angle α (: of the circumscribed surface of the metal fitting 8 to the convex portion 6 is:
The angle between the convex part circumscribing inclined part of the mold inner surface and the horizontal part)
If it is designed to be larger than the inclination angle β of the inscribed surface to the convex portion 6 of the die 11 (: the angle between the convex inscribed inclined portion of the outer surface of the metal fitting and the horizontal portion) (α> β), Ironing is applied to the material of the convex portion 6 sandwiched between the metal fitting 8 and the mold 11 to further improve the sealing property, which is preferable.

Further, when three or more plate materials are laminated to form a material, the material is sandwiched between the outer plate material 1 and the plate material 1A, for example, as shown in the case of stacking three plate materials in FIG. 4 (b). The inner plate 1B functions as an inner beam of the HF component (: the final product obtained by cutting unnecessary parts from the mold bulge component), and the strength of the HF component can be further improved. In order to apply the present invention in such a case, for example, as shown in FIG. 4 (a), the metal fitting 8 is arranged on the plate member 1 to be one outer plate in the same manner as in FIG. 1A plate material
Similarly to the plate material 1, the convex portion 6A and the opening 7A are formed and the metal fittings 8A are arranged. The metal fitting arrangement side of these plate materials 1 and 1A (the convex surface concave surface side)
The surfaces formed by facing each other are overlapped with both sides of the plate material 1B, which is one inner side, and the material formed by performing the suture welding 2 over the entire circumference of the edge of the region where the liquid is press-fitted is sandwiched by the pair of molds. At this time, the upper die 11 and the lower die 11A may clamp the circumscribing portion of the plate materials 1, 1A, 1B with the metal fittings 8, 8A and the peripheral portion thereof. From the viewpoint of further improving the sealing property,
As for the lower metal fitting 8A and the mold 11A, the inclination angle of the metal fitting 8A is set in the same manner as the above relationship between the upper metal fitting 8 and the mold 11.
It is preferable to make it larger than the inclination angle of 11A.

In the above-described embodiment, the case where all the tops of the protrusions are opened has been shown, but the present invention also includes the case where some of the tops of the protrusions are opened. When a part of the top of the convex portion is opened, for example, an embodiment using packing 13 as shown in FIG. 5, and another one is using packing 13 and nut 15 as shown in FIG. 6, for example. The preferred embodiment is

In FIG. 5, instead of the truncated cone-shaped metal fitting 8 of FIG. 2, a metal fitting 8B having a tubular portion for protruding from the opening 7 to the convex surface of the convex portion 6 is used. A packing 13 made of fluoroethylene (trade name: Teflon), urethane or the like is fitted and pushed by the upper mold 11 to the periphery of the opening 7 at the top of the convex portion 6. Further, the side portion (slope portion) of the convex portion 6 is clamped by the concave surface side portion of the metal fitting 8B and the upper mold 11. As a result, the top portion and the side portion of the convex portion 6 come into close contact with the concave side portion of the convex portion 6 of the metal fitting 8B without a gap, so that sufficient sealing performance can be secured.

In FIG. 6, instead of the metal fitting 8B of FIG. 5, a metal fitting 8C having a screw 14 on the outer surface of the tubular portion of the metal fitting 8B is used, and after the packing 13 is fitted to the threaded tubular portion, the screw 14 The packing 13 is pressed against the periphery of the opening 7 at the top of the convex portion 6 by screwing and tightening the nut 15 onto.
Further, the side portion (inclined portion) of the convex portion 6 is clamped by the concave surface side portion of the metal fitting 8C and the upper die 11. Thereby, the convex portion 6
Since the top portion and the side portion are in close contact with the convex portion concave surface side portion of the metal fitting 8C without a gap, sufficient sealing performance can be secured.

[0020]

Example As shown in FIGS. 7A and 7B, two flat plate materials 1 and 1A were cut out from a hot rolled steel plate having a thickness of 2.0 mm (Japan Iron and Steel Federation standard JSH440J), and the plate material 1 was HF processed. In the area to be cut off, a convex portion 6 is formed by pressing, and a hole 7 is drilled at the top of the convex portion, and a JIS standard SKD11 liquid injection metal fitting 8 is filled so as to fill the hole 7 and the concave surface of the convex portion. After arranging them, the plate materials 1A were overlapped with the metal fitting 8 sandwiched therebetween, and the edges of the region 10 into which the liquid was press-fitted were sewn along the entire circumference 2 to obtain a material. This material was bent and shaped into a shape as shown in FIG. 7 (b) by a press so as to be width-matched with the mold, and then inserted into the mold. At this time, the portion of the plate material around the metal fitting (the convex portion 6
And its vicinity) are a pair of upper and lower molds as shown in FIG.
Pressed against the metal fitting with 11 and 11A. Mold clamping force of 19600kN
As (2000 tf), water was injected from the liquid passage 9 of the metal fitting 8 into the inside of the material at a pressure of 200 MPa. As a result, the injected water is sufficiently sealed, and the material to which sufficient internal pressure has been applied by the injected water undergoes bulge deformation until it is inscribed in the mold without any gaps, and the product with the shape shown in FIG. was gotten. An unnecessary portion 14 of the product was cut off to obtain an HF part 13. The metal fitting 8 could be easily collected and reused.

In the conventional method shown in FIG. 3, the internal pressure was insufficient and the target shape of the HF component could not be obtained unless the injection nozzle and the injection port were welded to close the gap.

[0022]

According to the present invention, it is possible to obtain a sufficient sealing property with an inexpensive structure in hydroforming, which is performed using a material in which plate materials are overlapped and sewn and welded.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a material forming method in an embodiment of the present invention using two plate materials.

FIG. 2 is a front cross-sectional view illustrating an example of (a) a method of sandwiching a material in a mold and (b) a preferred inclination angle relationship between the metal fitting and the mold in the embodiment of the present invention using two plate materials.

FIG. 3 is an explanatory diagram showing a problem of the conventional technique.

FIG. 4 is a front cross-sectional view illustrating an example of (a) a method of sandwiching a material in a mold and (b) an HF component in the embodiment of the present invention using three plate materials.

FIG. 5 is a front cross-sectional view illustrating a method for holding a material in a mold according to an embodiment of the present invention using packing.

FIG. 6 is a front cross-sectional view illustrating a method of sandwiching a material with a mold in the embodiment of the present invention using a packing and a nut.

FIG. 7 is an explanatory diagram showing a process of an example.

[Explanation of symbols]

1,1A, 1B plate material 2 suture welding 3 inlets 4 injection nozzles 5 gap 6,6A convex part 7,7A opening 8,8A, 8B, 8C metal fittings (metal fittings for liquid injection) 9,9A liquid passage 10 Liquid press-in area 11 Mold (upper mold) 11A mold (lower mold) 12,12A mold through hole 13 HF parts 14 waste

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takaro Iguchi             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Made in Kawasaki             Technical Research Institute of Iron Co., Ltd. F-term (reference) 3D001 AA17 DA04

Claims (4)

[Claims] 1. A hydroform processing method in which two or more metal plate materials are superposed and sewn together and sandwiched by a pair of molds, and a liquid is press-fitted between the overlapping surfaces to form a mold bulge. Prior to superimposing, a convex portion is press-formed in the surface of at least one of the plate materials, and then a hole is formed at the top of the convex portion, and liquid injection is performed so as to fill the opening and the concave side space of the convex portion. When the metal fittings are arranged, another plate material is superposed on the side where the metal fittings are arranged, the entire circumference of the edge of the region where the liquid is press-fitted is stitched and welded, and when the material is clamped by the mold, the plate material is used by the same mold. The method of hydroforming, characterized in that the circumscribing portion of the metal fitting and the peripheral portion thereof are clamped. 2. The hydroform according to claim 1, wherein an inclination angle of an inscribed surface of the metal fitting to the convex portion is larger than an inclination angle of an outer contact surface of the mold to the convex portion. Processing method. 3. When the outer peripheral portion of the plate material with respect to the metal fitting and the peripheral portion thereof are pressed by the mold, a packing is fitted on the convex convex surface side portion of the metal fitting, and the packing is projected by the metal mold. The method for hydroforming according to claim 1 or 2, wherein the peripheral portion of the opening is pressed. 4. When the screw is provided on the outer surface of the convex-side convex surface portion of the metal fitting, and when the outer peripheral portion of the plate material with the metal fitting and its peripheral portion are pressed by the mold, the convex convex surface of the metal fitting is clamped. The hydroform according to claim 1 or 2, wherein after the packing is fitted to the side portion, the nut is screwed into the screw and tightened to press the packing to the peripheral portion of the opening of the convex portion. Processing method.