KR102300153B1 - Press forming method - Google Patents

Abstract

In the press forming method according to the present invention, a top plate portion (3) connected via a connecting edge portion (13) of a vertical edge portion (9) and a horizontal edge portion (11), and a longitudinal edge portion (9) in the top plate portion (3) ), a T-shaped part (1) having a wall part (5) formed in the transverse part (11) through the connecting edge part (13) and a flange part (7) formed continuously at the lower end of the wall part (5) by press molding a first forming process of drawing forming into an intermediate-shaped part 21 having a convex-shaped portion 15 formed on the connecting edge 13, and trimming of the intermediate-shaped part 21 to obtain a trimming part 41 a second forming step of forming the trimming part (41) into a T-shaped part (1) of a target shape by foam molding, the second forming step of pressing the convex portion (15) It is characterized in that the material flows into the continuous wall portion (5a) from the connecting edge portion (13).

Description

Press forming method

The present invention relates to a press forming method, and more particularly, to a press forming method for producing a T-shaped part for an automobile having a T-shape in plan view.

Among automotive parts, for T-shaped parts such as cross members, when press forming using a high-strength steel sheet of 590 MPa or more as a tensile strength, the forming process Wrinkles and cracks occurred at the same time, which was a problem. As a technique for press forming such T-shaped parts for automobiles, for example, Patent Document 1 discloses a center pillar ( A method of cold press forming a center pillar) is disclosed.

Japanese Patent Laid-Open No. 2016-2560

However, in the press forming method disclosed in Patent Document 1, the target part is a center pillar, and the wall portion has a low height (shallow forming depth), so that a T-shaped horizontal top portion (T-shaped joint portion) Although wrinkles sometimes occurred in the short portion of the top portion of the joint (Fig. 9 of Patent Document 1), the vertical top portion of the T (vertical top portion of the top plate of the T joint) In the long part), wrinkles and cracks hardly occurred. However, in a part such as a cross member handled in this application, wrinkles are generated in the longitudinal edge of the T-joint due to the high wall height (deep forming depth), and the connecting portion between the vertical wall and the flange of the T-joint. There is a problem that cracks occur.

The present invention has been made in view of the above problems, and its object is to generate wrinkles and cracks when press-forming a T-shaped part for automobiles having a T-shape such as a cross member using a high-strength steel sheet. It is to provide a press molding method for manufacturing by suppressing.

In order to solve the above-mentioned problem and achieve the objective, the press molding method which concerns on this invention is press-molding of a T-shaped part, A blank (blank) is an intermediate|middle shape part by deep drawing. (preformed-shape part) A first forming step, trimming the intermediate shape part to obtain a trimmed part, and forming the trimmed part into a target shape by crash forming and a second forming step of forming the T-shaped part, wherein the intermediate-shaped part to be molded in the first forming step has a T-shape in which a longitudinal portion and a transverse portion are connected by a joining top portion. a top plate portion, a wall portion continuously formed from the longitudinal edge of the top plate portion, a wall portion formed continuously from the horizontal edge portion of the top plate on the opposite side in the direction of the vertical edge portion, and the connecting edge portion formed continuously from the top plate portion a wall portion, a flange portion formed continuously at the lower end of the wall portion, a convex portion formed on the longitudinal side of the connecting edge portion in the top plate portion, a wall portion formed continuously with the connecting edge portion, and the same and a bending R portion in which a bottom R portion connecting a flange portion at the lower end of the wall portion is lifted upward, wherein the trimming step includes: T of the target shape in the second forming step Trimming a wall portion formed continuously from a portion of the flange portion, which is an unnecessary portion, and a transverse side portion of the top plate portion, and formed only on the opposite side of the longitudinal side portion, and a flange portion at the lower end of the wall portion from the intermediate-shaped component so as to become a female-shaped component, The second forming step is characterized in that the convex portion and the curved R portion are pressed and crushed, the material is introduced into the wall portion continuous to the connecting edge portion, and the target shape is formed.

Further, in the press forming method according to the present invention, in the above invention, the convex portion has a cross-sectional shape orthogonal to the longitudinal direction of the longitudinal side portion is formed continuously from the longitudinal side portion side of the connecting edge portion. It is characterized in that it has a shape continuously and convexly curved from the wall portion via a ridge portion connected to the wall portion.

In the present invention, a first forming process of forming a blank into an intermediate-shaped part by drawing forming, a trimming process of trimming the intermediate-shaped part to obtain a trimmed part, and forming the trimmed part into a target shape by form molding A second forming step of forming the T-shaped part is provided, and the intermediate-shaped part to be molded in the first forming step includes a T-shaped top plate portion in which a longitudinal portion and a transverse portion are connected by a connecting edge portion; A wall portion formed continuously from the longitudinal edge of the top plate portion, a wall portion formed continuously from the horizontal edge of the top plate portion on the opposite side in the direction of the longitudinal portion, a wall portion formed continuously from the top plate portion in the connection edge portion, and a lower end of these wall portions The flange portion formed continuously, the convex portion formed on the longitudinal side of the connecting edge portion of the top plate portion, and the bottom R portion connecting the wall portion continuously formed in the connecting edge portion and the flange portion at the lower end of the wall portion are lifted upward It has a raised curved R part, and the said trimming process is continuous from the part of the said flange part which is an unnecessary part, and the transverse part of the said top plate part from the said intermediate-shaped part so that it may become a T-shaped part of the said target shape in the said 2nd shaping|molding process. and trimming the wall portion formed only on the opposite side of the longitudinal edge direction and the flange portion at the lower end of the wall portion, and the second forming step is to press and crush the convex portion and the curved R portion to generate wrinkles generated in the connecting edge portion In addition to preventing cracks from occurring from the wall portion to the flange portion by introducing material into the wall portion from the convex portion formed on the connecting edge portion, the T-shaped part can be molded into the target shape. have.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the intermediate-shaped part and trimming part for press-molding the T-shaped part of the target shape which concerns on this embodiment ((a) intermediate-shaped part, (b) trimmed part, (c) target shape of T-shaped parts).
Fig. 2 is a view for explaining a portion where wrinkles and cracks occur when the T-shaped part made into the object of the present invention is molded by conventional drawing molding.
Fig. 3 is a view for explaining the shape of a blank used for forming an intermediate-shaped part by drawing forming in the first forming step in the press forming method according to the present embodiment.
4 is a view for explaining a mold used for molding an intermediate-shaped part by drawing molding in the first molding step in the press molding method according to the present embodiment.
5 is a view for explaining a punch used in the first forming step in the press forming method according to the present embodiment ((a) side view (width direction), (b) side view (length direction) ), (c) planar view).
6 is a view for explaining a mold used for molding a T-shaped part having a target shape by foam molding in the second molding step in the press molding method according to the present embodiment.

EMBODIMENT OF THE INVENTION Below, one Embodiment of the press molding method which concerns on this invention is demonstrated. In addition, this invention is not limited by this embodiment.

The press forming method according to the present embodiment uses a T-shaped part 1 as shown in FIG. A first forming step of forming the shape part 21, a trimming step of trimming the intermediate shape part 21 to form a trimming part 41 as shown in Fig. 1(b), and a trimming part by form molding (41) is provided with the 2nd shaping|molding process of shaping|molding the T-shaped part 1 of a target shape as shown in FIG.1(c). Hereinafter, first, the T-shaped part 1 made into a shaping|molding object is demonstrated, and then, the press-molding method which concerns on this embodiment is demonstrated. In addition, in the following description, the same code|symbol is attached|subjected about the site|part which has the same function, and overlapping of description is avoided.

<T-shaped part (1)>

The T-shaped part 1 is continuous from the T-shaped top plate part 3, the wall part 5 continuous from the top plate part 3, and the wall part 5, as shown to FIG.1(c). and a flange part 7 to connected by intervening. Here, as shown in Fig. 1(c), the connecting edge portions 13 are portions having a shape in which both sides top portions are curved.

The wall portion 5 is continuously formed from the longitudinal portion 9 of the top plate portion 3 through the connecting edge portion 13 to the horizontal portion 11 through the ridge portion 17 . And the flange part 7 is continuously formed through the bottom R part 19 from the lower end of the wall part 5. As shown in FIG.

＜Why wrinkles and cracks can be suppressed at the same time＞

When a T-shaped part 1 having a deep forming depth such as a cross member is draw-formed in one step using a high-strength steel sheet having a tensile strength of 590 MPa class or higher, as shown in FIG. Wrinkles may occur in the connecting edge 13, and cracks may occur from the continuous wall 5b through the ridge 17b to the flange 7b in the connecting edge 13. It was difficult to press molding with fewer problems.

In the press-molding method according to the present embodiment, the T-shaped part 1 can be press-formed while simultaneously suppressing both wrinkles and cracks for the following reasons.

In the first forming step, the convex portion 15 (Fig. 1(a)) is formed in the connecting edge portion 13 of the intermediate-shaped part 21 so as to be positively surplus material, so that in the forming process, Excess metal can be drained out, and the generation of wrinkles in the T-shaped connecting edge 13 is prevented.

In the subsequent trimming process, an unnecessary part is trimmed from the intermediate-shaped part 21 so that it may become the said target shape in the 2nd shaping|molding process (FIG. 1(b)), In the 2nd shaping|molding process, the intermediate-shaped part 21 It becomes easy to flow in material from the convex part 15 provided to the wall part 5a.

And in a 2nd shaping|molding process, material flows into the wall part 5a from the convex part 15 by pressing and shaping|molding so that the convex part 15 may be crushed, and the wall part 5b of the T-shaped part 1 is carried out. ) to the flange portion 7b to prevent the occurrence of cracks (Fig. 1(c)).

Moreover, in the press forming method which concerns on this embodiment, the die R (die R) of the bottom R part 19a which connects the wall part 5a and the flange part 7a in a 1st forming process is the bottom of a target shape. Since molding (FIG. 1(b)) so as to enlarge (shading off) the die R of the R part 19b (FIG. 1(c)), the second from the bottom R part 19a thus enlarged The material can be introduced in the forming process, and the occurrence of cracks can be further prevented.

<Press molding method>

Next, the 1st shaping|molding process, the trimming process, and the 2nd shaping|molding process of the press molding method which concerns on this embodiment are demonstrated.

«First molding step»

In the first forming step, the blank is drawn by drawing forming a T-shaped top plate portion 3 , a wall portion 5 continuously formed from the top plate portion 3 , and a plan formed continuously at the lower end of the wall portion 5 . Formed into an intermediate-shaped part 21 (Fig. 1(a)) having a branch portion 7 and a convex portion 15 formed on the longitudinal side portion 9 side of the connecting edge portion 13 of the top plate portion 3 As a result, for example, the blank 31 shown in FIG. 3 is punched using the die 39 provided with the punch 33 shown in FIG. 4, the die 35, and the blank holder 37. (33) Draw molding as a positional relationship with

The wall part 5 is a wall part 5c continuously formed from the longitudinal edge part 9 of the top plate part 3, and the top plate part 3 on the longitudinal edge part 9 side, as shown to Fig.1 (a). A wall portion 5d continuously formed from the horizontal edge portion 11, a wall portion 5a formed continuously from the connection edge portion 13 of the top plate portion 3, and a horizontal edge portion 11 on the opposite side in the direction of the vertical edge portion 9 and a wall portion 5e formed continuously from the

In addition, the longitudinal edge part 9 side of the connection edge part 13 is a site|part close|similar to the longitudinal edge part 9 among the connection edge parts 13. As shown in FIG. And, the convex-shaped part 15 is a shape curved upwardly convexly formed on the longitudinal edge part 9 side of the connection edge part 13, and, as shown in FIG. 5, at the site|part corresponding to the connection edge part 13. The convex-shaped forming part 33a of the shape curved upward convexly is formed using the formed punch 33. As shown in FIG.

Here, the convex-shaped portion 15 has a cross-sectional shape orthogonal to the longitudinal direction of the longitudinal side portion 9 and is connected to the wall portion 5a formed continuously from the longitudinal side portion 9 side of the connecting edge portion 13. A shape curved continuously and convexly from the wall part 5a through the part 17a may be sufficient.

Further, in the bottom R portion 19a where the wall portion 5a continuous from the convex portion 15 and the flange portion 7a are connected, the trimming part 41 is punched 51 (Fig. 6) in the second forming step. Refer to), the curved R portion 19c is formed in order to prevent it from flopping up and displaced from the tool of press forming (Fig. 1(b)). Here, the curved R part 19c is higher than the bottom R part 19b by, for example, setting the die R of the bottom R part 19a to be larger than the die R of the bottom R part 19b of the target shape. It can be formed to lift in the direction.

In addition, in the intermediate|middle-shaped part 21 shown to Fig.1 (a), the bellows-shaped wall part 5e and the wall part continuous on the opposite side of the longitudinal edge part 9 direction in the horizontal edge part 11 of the top plate part 3 are carried out. Although the flange part 7d continuous from (5e) is further formed, the wall part is not formed continuously in the left and right edge parts 11a of the transverse side part 11. As shown in FIG.

In the first forming step, when drawing-molding to the intermediate-shaped part 21, a portion corresponding to the flange portion 7d of the blank 31 is clamped by the die 35 and the blank holder 37 ( It is for suppressing generation|occurrence|production of the wrinkle in the transverse side part 11 by carrying out 挾持 (FIG. 4), and for preventing that a crack generate|occur|produces in the edge part 11a vicinity of the transverse side part 11.

Moreover, the shape of the blank 31 (refer FIG. 3) is set by cutting a steel plate so that the wall part 5e and the flange part 7d may be formed, and the wall part continuous from the edge part 11a may not be formed.

≪Trimming process≫

The trimming process is a process of trimming the intermediate-shaped part 21 to obtain the trimming part 41 (FIG. 1(b)), and an unnecessary portion from the intermediate-shaped part 21 so as to obtain the target shape in the second forming process. trim the The trimming part 41 is a part of the transverse side portion 11 of the intermediate-shaped part 21 so that the T-shaped part 1 molded in the second forming step has a target shape without requiring additional trimming. The flat surface of the edge part 11a on both sides of the left and right sides, the part on the side where the wall part 5e and the flange part 7d formed only on the opposite side of the longitudinal edge part 9 direction among the transverse edge part 11 are continuous, and the flange part 7 The side end portions 7c on the left and right sides are trimmed when viewed from .

Above all, in the trimming step of the press molding method according to the present embodiment, after the second molding step, the region may be trimmed to obtain a target shape.

«Second molding process»

A 2nd shaping|molding process uses the metal mold|die 55 provided with the punch 51 and die 53 (die 53a and die 53b) as shown in FIG. 6, trimming component 41 (FIG. 1(b)) is a step of forming a T-shaped part 1 (Fig. 1(c)) of a target shape by foam molding, by pressing and crushing the convex part 15 of the trimming part 41 to form a wall part A material is poured into (5a), and the curved R part 19c is molded without cracking.

In the second forming step, in order to make it easy to flow material into the wall portion 5a from the convex portion 15, for example, the convex portion 15 of the top plate portion 3 in the trimming part 41 . is not pressed with a pad, and the remaining portions (longitudinal portion 9 and transverse edge portion 11) may be foam-molded with a punch 51 and a die 53 while pressing the pad with the pad.

As described above, according to the press forming method according to the present embodiment, even when a high-strength steel sheet having a tensile strength of 590 MPa class or higher is used, suppression of wrinkles and avoidance of cracks are achieved simultaneously, and the T-shaped part 1 having a deep forming depth is pressed. can be molded.

In addition, in the above description, the convex part 15 of the intermediate-shaped part 21 is curved continuously and convexly from the wall part 5a via the ridge part 17a in the connecting edge part 13. Although formed, if material can flow from the convex part 15 to the wall part 5a in the form forming of the trimming part 41 in the second forming process, the shape of the convex part 15 is It is not limited to this, In the connection edge part 13, it is formed inside the ridgeline part 17a, and the thing convex upward may be sufficient.

In addition, in the above description, the T-shaped component 1 is a shape in which two T-shaped longitudinal sides are oppositely connected at both ends in the longitudinal direction as shown in FIG. A T-shaped component having a T-shape may be press-molded at one end of the direction.

Industrial Applicability

According to the present invention, a T-shaped part for automobiles having a T-shape, such as a cross member, when press-formed using a high-strength steel sheet, to provide a press forming method for manufacturing by suppressing the occurrence of wrinkles and cracks can

1: T-shaped part
3: top plate part
5, 5a, 5b, 5c, 5d, 5e: wall
7, 7a, 7b, 7d: flange part
7c: side end
9: Longitudinal region
11: transverse part
11a: end
13: connecting edge
15: convex shape
17, 17a, 17b: Ridge
19, 19a, 19b: bottom R part
19c: Curvature R part
21: middle shape part
31: blank
33 : Punch
33a: convex shape forming part
35 : die
37: blank holder
39: mold
41: trimming parts
51 : Punch
53, 53a, 53b: die
55: mold

Claims (2)

A method for press molding a T-shaped part, comprising:
A first forming step of forming a blank into an intermediate-shaped part by drawing forming, a trimming process of trimming the intermediate-shaped part to obtain a trimmed part, and forming the trimmed part into a target shape of the T-shaped part A second molding process of molding with
The intermediate-shaped part to be molded in the first forming step includes a T-shaped top plate portion in which a longitudinal portion and a transverse portion are connected by a connecting edge portion, a wall portion continuously formed from the longitudinal portion of the top plate portion, and a longitudinal portion in the longitudinal direction. On the opposite side, a wall portion formed continuously from the lateral edge of the top plate portion, a wall portion formed continuously from the connection edge portion of the top plate portion, and a flange portion formed continuously at the lower end of the wall portion,
Further, a cross-sectional shape formed on the longitudinal side of the connecting edge of the top plate portion and perpendicular to the longitudinal direction of the longitudinal portion is through a ridge connecting to a wall continuously formed from the longitudinal side of the connecting edge through a ridge, the It has a convex-shaped part continuously curved convexly from the wall part, and a curved part R part which lifts upward the bottom R part connecting the wall part continuously formed in the said connection edge part and the flange part of the lower end of the wall part,
In the second forming step, the trimming step is formed continuously from a part of the flange portion which is an unnecessary portion and a transverse portion of the top plate portion from the intermediate-shaped part so as to become a T-shaped part of the target shape in the second forming step, in the longitudinal direction. trimming the wall portion formed only on the opposite side of the
In the second forming step, the convex portion and the curved R portion are pressed and crushed, and the material flows into the wall portion continuous to the connecting edge portion to form a target shape. delete

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