JPH08103825A - Method for forming forked member and die therefor - Google Patents

Abstract

PURPOSE: To uniformize the inflow of material in bending and to prevent crack ing in working by forming a forked product from a metallic sheet, inserting an auxiliary core bar into one of the projected parts of the forked part and moving the auxiliary core bar towards the other projected part. CONSTITUTION: With the cam 8 of an upper die brought into contact with a backup block 10 fixed on a lower die 9 and with the cam face 12 of an auxiliary core bar 6, and subsequently with the cam 8 of the upper die further lowered, the auxiliary core bar 6 is pushed out to a corner R3 side and moved in the direction of the arrow. Through this series of operation of the upper die cam 8 fixed on the upper die 7 and the backup block 10 fixed on the lower die 9, bending is performed for the projected part 2 of a product 1 which is preliminarily formed in the process of moving the auxiliary core bar 6 to a prescribed position. As a result, the corner R of the preliminarily formed product 1 becomes smaller than the corner R of a target product and compression molded, eliminating cracking due to tension on the end face of the product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to molding of a bifurcated member, and more particularly to a molding method and a die for preventing bending cracks generated at the corners of the root of the bifurcated member.

[0002]

2. Description of the Related Art Conventionally, a bifurcated member as shown in FIG. 2 has been widely used as a component such as a suspension arm of an automobile which is designed in space. In this case, when the iron plate structure is used, the corner R portion 5 is severely processed when the protrusion 2 of the product 4 shown in FIG. It becomes a part. Therefore, an expensive material having excellent ductility is often used as a raw material, or an expensive forged product or cast product is adopted instead of forming from an iron plate.

5A to 5F show conventional processing steps of these members in a product having an iron plate structure. In these steps, the material 14 cut into a constant shape as shown in FIG. 5A is converted into the diaphragm 15 in FIG. 5B and the materials 15 in FIGS.
The outer peripheral trim 16 and the bending 17 in FIG. 7E are sequentially processed to obtain the finished product 18 in FIG. Further, as shown in FIG. 2, when the curvature of the corner R portion 5 of the product 4 becomes smaller, the inflow of the material 14 is reduced in the drawing 15 step shown in FIG.
There is a work crack on the ridge line 19 of the
In the seven steps, the elongation rate of the product end surface 20 becomes high, and the product end surface 20 is cracked, which makes it difficult to perform molding by pressing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to study a press forming method for a bifurcated member whose corner R portion is severely worked, and to prevent work cracking by making the material inflow uniform during bending. A method for forming a bifurcated member. Another object of the present invention is as a cam type bending die,
It is an object of the present invention to provide a bifurcated member molding die that realizes severe bending without tension by providing a simple auxiliary core metal and a backup block.

[0005]

[Means for Solving the Problems] The above objects are, in the press forming of a bifurcated member, a press step of forming a bifurcated product from a single metal plate, and an auxiliary core in one convex portion of the bifurcated part. This is achieved by a method for forming a bifurcated member, which comprises a bending step of inserting gold and moving the auxiliary core metal toward the other convex portion.

Further, the above-mentioned object is to provide a bifurcated member molding die with an auxiliary core metal which is inserted into one convex portion of the bifurcated product and on which the bifurcated product can be placed. An upper die cam movable while contacting the cam surface of the auxiliary core metal, and a backup block of the upper die cam fixed to the lower die are also provided. To be achieved.

[0007]

According to the present invention, working cracks that occur during the working of a bifurcated member can be solved, and molding can be performed in bending of a small corner R portion without using a high-grade material. Further, according to the present invention, the auxiliary core metal is inserted into the molding of the convex portion of the fork or two, and the convex portion is forcedly bent toward the convex portion of the other, so that the material flow by the bending process is improved. ,
Trouble such as lack of material was eliminated and more uniform press molding was realized.

[0008]

The present invention will be described in more detail below with reference to the drawings of the embodiments. The present invention has realized a method of moving an auxiliary core metal by using a cam when performing a bending work with a large working degree. In this method, when the upper mold is lowered, the slope of the cam moves along the slope (cam surface) of the auxiliary core metal so that the convex portion of the product on the auxiliary core metal is preformed in advance and other corners are not formed. It is forcibly bent in the direction of the part. In this case, with respect to the length direction of the cam,
It is necessary to effectively apply a stress load in the perpendicular direction (bending direction) as a bending stress. That is, by adjusting the bending pushing force between the cam and the auxiliary core metal, and between the cam and the backup block, the bending of the corner convex portion of the bifurcated product can be accurately formed without material thinning. It is a thing.

1, 3 and 4 show an example of a preformed product and its bending process. In this embodiment, as shown in FIG. 2, the molding is performed when the corner R portion 5 of the product 4 is small, that is, when the bending angle of the protrusion 2 is large. As shown in FIG. 1, in the present invention, the corner R portion 3 of the preformed product 1 is formed larger than the corner R portion 5 of the product 4 in FIG. Therefore, the protrusion 2 in FIG. 1 has an angle of a plane angle θ °, and is preformed into a product that is bent to the outside by a large amount.

The molding process of the preformed product 1 will be described below. The molding process is shown in FIGS. 3 (a) and 3 (b) and FIGS. 4 (a) and 4 (b) in order. First, in the process of FIG. 3A, the lower mold 9 is opened with the upper mold 7 and the lower mold 9 open.
A backup block 10 is fixed to the upper mold 7, and an upper mold cam 8 is fixed to the upper mold 7. A preformed product 1 as a work material and an auxiliary core metal 6 for mounting the product 1 are set in the vicinity of these.

At this time, the protrusion 2 of the preformed product 1
With the auxiliary core metal 6 inserted therein, the auxiliary core metal 6 is opposed to the backup block 10, and the cam surface 11 of the upper die cam 8 is opposed to the cam surface 12 of the core metal 6. Further, the protrusion 2 is set to be substantially parallel to the backup block 10, and the tip of the protrusion 2 is positioned so as to be located substantially in the center of the backup block 10. Then, FIG.
In the forming step shown in (b), the upper die cam 8 fixed to the upper die 7 is lowered between the auxiliary core 6 on which the protrusion 2 is placed and the backup block 10 as the upper die 7 is lowered. Then, slide them into contact with the cam surfaces. After that, the tip of the cam surface 11 of the upper die cam descends to a state in which the tip of the cam surface 11 of the upper die cam is almost completely fitted in the gap formed by the cam surface 12 of the auxiliary core metal and the backup block 10.

Then, as shown in the step of FIG. 4A, the upper die cam 8 is in contact with the backup block 10 fixed to the lower die 9 and the cam surface 12 of the auxiliary core metal 6, and thereafter the upper die cam 8 is further in contact. The auxiliary core metal 6 is pushed out to the corner R3 side by the lowering of 8 and moves in the direction of the arrow in the figure. By a series of operations of the upper die cam 8 fixed to the upper die 7 and the backup block 10 fixed to the lower die 9, the protrusion of the product 1 preformed in the process of moving the auxiliary core metal 6 to a predetermined position. Bend 2 is performed.

When the molding is completed, the product is removed as shown in FIG. 4B, and then the auxiliary core bar 6 is returned to its original position by the spring 13 for returning. The corner R portion 3 of the product 1 preformed by the molding of this embodiment
Becomes smaller, and the shape and dimensions of the corner R portion 5 of the intended product 4 are finished. Further, since the corner R portion 3 is compression-molded by the method of the present invention, cracking of the product end surface 20 due to tension (elongation) does not occur.

[0014]

According to the present invention, the auxiliary core metal is used, and the forming method of bending the bifurcated member while applying the compressive stress without excessively bending the member is realized. The occurrence of cracking can be significantly reduced.
Furthermore, the molding method of the present invention replaces a bending-molded member that is difficult to process with a cost-effective material instead of one that was conventionally dealt with by an expensive forging material or casting material with good workability. It is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a shape example of a large corner R portion of a preformed product according to the present invention.

FIG. 2 is a diagram showing an example of a product having a small corner R portion to which the present invention is applied.

FIG. 3 is a diagram showing steps of the forming method of the present invention, showing (a) a state of setting a processing member on an auxiliary core metal, and (b) a state at the time of starting bending forming processing.

FIG. 4 is a diagram showing the steps of the molding method of the present invention, showing (a) the moving state of the auxiliary core metal, and (b) the state of demolding at the end.

FIG. 5 is a diagram showing a conventional forming process of a forked member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Preformed product 2 ... Projection part 3 ... Preformed corner R part 4 ... Product 5 ... Corner R part 6 ... Core 7 ... Upper mold 8 ... Upper mold cam 9 ... Lower mold 10 ... Backup block 11 ... Cam surface 12 ... Mandrel cam surface 13 ... Spring 14 ... Cut material 15 ... Drawing 16 ... Peripheral trim 17 ... Bending 18 ... Finished product 19 ... Ridge line 20 ... Product end surface

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B60G 7/00 9143-3D

Claims (2)

[Claims] 1. A press step of forming a bifurcated product from a single metal plate in press-forming a bifurcated member, and inserting an auxiliary core into one convex portion of the bifurcated part, and then the auxiliary core. 2. A method for forming a bifurcated member, which comprises a bending step in which one is moved toward the other convex portion. 2. A bifurcated member molding die is provided with an auxiliary core metal which is inserted into one convex portion of the bifurcated product and on which the bifurcated product can be mounted, and a cam of the auxiliary core metal. A bifurcated member molding die, comprising an upper die cam movable so as to be in contact with a surface thereof, and a backup block of the upper die cam being fixed to a lower die.