JP2836326B2 - Drawing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing press forming apparatus capable of suppressing generation of cracks and wrinkles.

[0002]

2. Description of the Related Art A drawing press forming apparatus is known, for example, from Japanese Utility Model Laid-Open No. 56-147927. As shown in FIG. 5, the conventional drawing apparatus has a die 2 'and a punch 4', and the workpiece 1 'is pushed into the die 2' by the punch 4 '. Since the workpiece 1 'is moved toward the center during the molding, the outer peripheral portion, that is, the flange 1a' is formed.
Then, as shown in FIG. 7, a circumferential compressive force εθ is generated.

The circumferential compressive force εθ can be obtained by plastically deforming the outer peripheral portion of the workpiece 1 ′ so as to increase the thickness as shown in FIG. 8 or by using the flange of the workpiece 1 ′ as shown in FIG. Attempt to cause buckling (wrinkles) in 1a '. In order to suppress the generation of wrinkles, the draw forming apparatus includes a wrinkle pressing member (blank holder) 3 'corresponding to the die 2' as shown in FIG. The wrinkle holding member 3 'is urged toward the die 2' with a wrinkle holding force P '. This wrinkle holding force P 'is applied to the pin 5' by a machine side air source (not shown).
However, the pressure variation is large and requires fine adjustment for each processing. As a method of absorbing this variation, an excessive wrinkle holding force P 'is applied, and an interference member 6' is interposed between the die 2 'and the wrinkle holding member 3' as shown in FIG. It is a general method to provide a constant gap 11 'between the die and the die 2' and the wrinkle holding member 3 '.

[0004]

However, since the thickness of the flange 1a 'is increased by the compressive stress in the circumferential direction, the gap between the workpiece 1', the die 2 ', and the wrinkle holding member 3' even during the processing. It is necessary to set a large gap (about 15 to 20% of the original thickness of the workpiece) in consideration of the increase in the thickness of the flange 1a '. For this reason,
There is a problem that the flange 1a 'cannot withstand the increase in thickness and buckles in the early stage of processing, and some wrinkles occur. If the gap is set too small in order to reduce the generation of wrinkles, the gap disappears when the thickness of the flange 1a 'is increased, and the excessive wrinkle pressing force P' is applied to the workpiece. In addition, there is a problem that the sliding resistance between the workpiece 1 ', the die 2', and the wrinkle holding member 3 'increases, and the product is broken or cracked.

[0005] It is an object of the present invention to provide a drawing apparatus capable of suppressing the occurrence of cracks and wrinkles in a product.

[0006]

According to the present invention, the above object is achieved by the following drawing apparatus. That is, a movable die capable of moving up and down, a die provided on the movable die, a fixed die provided opposite the movable die, a punch provided on the fixed die corresponding to the die, and a periphery of the punch. In a draw forming apparatus including a wrinkle holding member provided corresponding to the die and urged in the die direction, and an interference member provided between the die and the wrinkle holding member, the die and the wrinkle holding member A draw forming device, wherein at least one of the two forms a slanted surface in which a gap between the die and the wrinkle holding member increases toward the center of the die.

[0007]

In the drawing apparatus of the present invention, the flange is moved toward the center of the die as the drawing is advanced, and the flange thickness increases as the amount of the movement increases. Since the gap between the die and the wrinkle holding member is increased toward the center of the die in accordance with the increase in the thickness of the flange, regardless of the amount of the flange moved toward the center of the die, the outer end of the flange is The gap between the part, the die and the wrinkle holding member is always kept at a substantially constant minute gap. As a result, the flange is pressed by the die and the wrinkle holding member while maintaining the slidability, so that no wrinkles or cracks occur.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG. In FIG. 1, a die 2 is fixed to an upper die base of a press, which is a movable die 7 that can move up and down, by bolts 21. Facing the movable mold 7,
A lower mold base that is a fixed die 8 is provided, and the punch 4 is fixed to the fixed die 8 by bolts 22 so as to face the die 2. The punch 4 is opposed to the molding recess of the die 2.

A wrinkle holding member 3 is provided around the punch 4 so as to face the die 2. The wrinkle holding member 3
The die 2 is connected to the die 2 by an air cylinder
It is urged in the direction of. The wrinkle holding member 3 is vertically opposed to the die face 2a around the concave portion of the die 2, and suppresses buckling of the flange 1a of the workpiece 1.

An interference member 6 is interposed between the die 2 and the wrinkle holding member 3, and the thickness of the interference member 6 is smaller than the initial thickness of the workpiece 1 (three-thirds of the original plate thickness). (About 5%). By interposing the interference member 6, even if the wrinkle holding member 3 is urged toward the die 2, the die 2 and the wrinkle holding member 3 do not strongly press the workpiece 1 and at the beginning of molding. The end 1b of the workpiece 1 and the die 2,
A minute gap 12 (a gap of about 3 to 5% of the original plate thickness) exists between the wrinkle holding members 3.

As shown in FIGS. 2 and 3, the die face 2a of the die 2 is provided with an inclination θ for increasing the gap between the die 2 and the wrinkle holding member 3 toward the center of the die. . Therefore, in the embodiment of FIGS. 2 and 3, the die face 2a is an inclined surface. This inclination starts from a die portion 2b corresponding to a point extending from the flange end portion 1b of the workpiece 1 before molding to the center of the die about the thickness of the workpiece 1. The reason why a parallel portion having a thickness of approximately the workpiece thickness is left in the workpiece 1, the die portion 2b, and the wrinkle holding member 3 in the radial direction is to suppress buckling of the workpiece 1 at the initial stage of molding by surface contact. It is.

The inclination θ given to the die face 2a is
It is set as follows. As molding progresses,
The thickness of the flange 1a increases from the state shown in FIG. 2 to the state shown in FIG. 3 while being moved toward the center of the die. The gap is set so as to have the same size (3-5% of the original plate thickness) as before molding. Usually, θ is about 1 °.

In the examples shown in FIGS. 2 and 3, the inclination θ is formed on the die face 2a.
As long as the gap between them is increased toward the center of the die, the gap may be formed on the wrinkle holding member 3 side as shown in FIG. Therefore, in the embodiment of FIG. 4, the upper surface 3a of the wrinkle holding member 3 is an inclined surface. Even when the inclination θ is formed on the wrinkle holding member 3, the setting and the starting point of the inclination θ are the same as those described in the case where the inclination θ is formed on the die face 2a.

Next, the operation will be described. First, the workpiece 1 is set on the wrinkle holding member 3 to which the excessive wrinkle holding pressure P has been applied by the air cylinder (not shown) via the pin 5. Next, the upper die table, which is the movable die 7 fixed to the upper ram (not shown) of the press machine, is lowered, and the workpiece 1 is held by the die 2 and the wrinkle holding member 3. However, the interference member 6
As a result, the excessive wrinkle pressing pressure P is not directly applied to the workpiece 1.

Further, when the upper die table, which is the movable die 7, is lowered, drawing of the workpiece 1 proceeds, and the flange 1a of the workpiece 1 is moved toward the center of the die 2 while being moved in the circumferential direction. A compressive stress is applied, and the thickness of the flange 1a increases. However, the die face 2a of the die 2 is provided with an inclination θ in the radial direction in consideration of an increase in the thickness of the flange 1a.
Draw forming proceeds without constantly pressing strongly the flange 1a of the above and without generating an excessive gap between the flange 1a, the die 2 and the wrinkle holding member 3. Therefore, no wrinkles or cracks occur in the workpiece 1. By setting the wrinkle holding pressure P to be excessive, fine adjustment of the wrinkle holding pressure P for each processing is not required.

[0016]

According to the present invention, in the drawing apparatus, at least one of the die 2 and the wrinkle holding member 3
Since the inclined surfaces 2a and 3a in which the gap between the die 2 and the wrinkle holding member 3 increases toward the center of the die are formed, molding can be performed without causing wrinkles in the workpiece 1, and The movement resistance of the flange 1a is also reduced, and no cracking of the workpiece 1 occurs, and the forming limit can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a drawing apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a portion corresponding to a portion A in FIG. 1 when an inclined surface is formed on a die face in the apparatus of FIG.

FIG. 3 is a cross-sectional view showing a state in which draw forming has progressed in the apparatus portion of FIG.

4 is an enlarged cross-sectional view of a portion corresponding to a portion A in FIG. 1 when an inclined surface is formed on a wrinkle holding member in the apparatus of FIG.

FIG. 5 is a cross-sectional view of a conventional drawing apparatus without an interference member.

FIG. 6 is a cross-sectional view when a conventional drawing apparatus has an interference member.

FIG. 7 is a stress diagram acting on a minute portion of a flange of a workpiece.

FIG. 8 is a cross-sectional view showing a state where the thickness of a small portion of the flange is increased by a circumferential compressive force.

FIG. 9 is a cross-sectional view showing a state where a minute portion of a flange buckles due to a circumferential compressive force.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work material 1a Flange 2 Die 2a Die face (inclined surface) 3 Wrinkle holding member 3a Upper surface of a wrinkle holding member (inclined surface) 4 Punch 5 Pin 6 Interference member 7 Movable type 8 Fixed type

Claims (1)

(57) [Claims] A movable die capable of moving up and down, a die provided on the movable die, a fixed die provided facing the movable die, and a punch provided on the fixed die corresponding to the die; A wrinkle holding member provided corresponding to the die around the punch and urged in the die direction, and an interference member provided between the die and the wrinkle holding member, a draw forming apparatus including: A draw forming apparatus, wherein at least one of the wrinkle holding members has an inclined surface in which a gap between the die and the wrinkle holding member increases toward the center of the die.