JPS60166122A - Method of forming sheet and its forming die - Google Patents

Abstract

PURPOSE:To improve accuracy of products and to reduce cost by providing a freely rotatable cam member having a negative angle forming part in the first die, and placing a cam having a negative angle forming part facing the above- mentioned cam member in the second die. CONSTITUTION:A columnar cam member 2 is provided in a lower die 3 to allow free rotation, and a negative angle forming part 4 is formed on the edge of a groove 1 of the cam member 2 near upper face of the lower die 3. A slide cam 10 is provided facing the cam member 2 in an upper die 9, and a negative angle forming part 12 is formed at lower end of its driven cam 11. When the upper die 9 is lowered from the top dead center, the driven cam 11 comes into contact with a rotary late 8 first, and the cam member 2 is rotated clockwise. Then, the cam 11 moves to the left, and the work W is negative angle formed by the negative angle forming part 4 of the rotated cam member 2 and the negative angle forming part 12 of the slide cam 10. When the upper die 9 goes up, the cam member 2 rotates automatically counterclockwise, and the work W is taken out from the lower die 3. Thus, the weight of the dies is reduced, and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming a thin plate and a mold thereof.

Negative angle forming of thin plates such as sheet metal and plastic is usually performed using a slide cam. By the way, the negative angle forming mentioned here has a forming part that enters into the lower mold from the machining trajectory of the upper mold when the workpiece placed on the lower mold is molded by lowering the upper mold vertically and colliding with each other. Say molding. Conventional negative angle forming processing of thin sheet products involves placing the workpiece on the lower mold, lowering the upper mold vertically downward, driving the lower mold's passive cam with the upper mold's operating cam, and processing from the lateral direction. When processing was completed and the upper die rose, the passive cam was moved back by a spring. In this case, the molding part of the passive cam that slides from the outside of the workpiece in the lateral direction to mold the workpiece is formed into the same integral shape as the molding part of the workpiece. In the forming section, the workpiece must be removed from the lower die after machining is completed, so the negative angle part of the lower die must be divided and moved back, or the negative angle part must be deleted to enable the workpiece to be taken out. If the degree of negative angle is slight, it will not be much of a problem, but if the degree of negative angle is large or the product is a long, slender bar with a groove-like cross section, for example, parts such as the front pillar outer of sheet metal parts of automobiles. Because the groove width of the workpiece is narrow, if the lower mold part that forms a negative angle is divided or deleted, not only will the molded part of the passive cam not be able to clearly form the shape, but the strength of the lower mold will also be insufficient, resulting in a negative angle. Molding was impossible. In addition, in negative angle forming using a slide cam, the passive cam is guided and slid over a considerable linear distance, so it is not always easy to repeatedly and accurately position the passive cam in a predetermined position. However, it is difficult to produce products with stable quality, and in some cases twisting or distortion may occur, which may require modification of the product.
It is practically impossible to modify products that have three-dimensional curved surfaces and curves, such as components of the outer skin of an automobile such as the front pillar outer.In the case of automobile sheet metal assembly, it is difficult to connect with other parts. Due to the poor relationship, it was not possible to provide high-quality automobile sheet metal structures, and it was not possible to maintain the specified product precision of thin sheet molded products. Additionally, when a slide cam is used, a large passive cam or heel is installed on the side of the lower die on which the work is placed, which increases the area of the lower die, which increases the weight of the die and makes it an expensive die. .

Therefore, in order to solve the above-mentioned problems, the present invention attempts to solve these problems based on a novel idea that has never existed before, which is to convert the vertical linear motion of the press into rotational motion. It is.

Hereinafter, the present invention will be described in detail based on specific embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic diagram of the left and right sides of a completed front pillar outer, which is a sheet metal part for an automobile, molded using this mold. In the drawing, the lower part is Ishikawa and the upper part is the left corner. This front pillar outer is part of the front door, part of the frame of the windshield, and also part of the frame that supports the roof panel, and has connection parts with many parts. However, it is a product that requires strict product precision, and if this precision is not met, it will not be possible to produce a high quality sheet metal car body. Moreover, this front pillar outer has a three-dimensional curved surface and curve because it constitutes the outer panel part of the automobile. The part that is formed at a negative angle by this mold is the part indicated by 8, and its cross section is the second
It is shown as work W in the figure. That is, after negative angle forming, the state of the work W shown by the two-dot chain line changes to the state shown by the solid line. Incidentally, in this press working step, drawing is first performed, then outer periphery trimming is performed to the state shown by the two-dot chain line, and the next third step is the main forming step. FIG. 3 shows a plan view of the lower mold, and FIG. 4 shows a plan view of the upper mold.

A cylindrical cam member 2 with a groove 1 carved in the axial direction of the peripheral wall is rotatably provided on a lower mold 3. The upper surface of the lower mold 3 is formed into a shape on which a workpiece W can be placed, and a negative angle molded portion 4 is formed at the edge of the groove 1 of the cam member 2 near the upper surface of the lower mold 3. After molding the workpiece W, an automatic return device 5 is embedded in the lower mold 3 for rotating and retracting the cam member 2 to the state shown by the two-dot chain line so that it can be taken out from the lower mold.

In this embodiment, the automatic return device 5 brings the bushing pin 7 urged by the coil spring 6 into contact with the lower surface of the tip of the rotary plate 8 fixed to the edge of the other groove 1 of the cam member 2.

Note that the automatic return device 5 can be provided using a pneumatic device, a hydraulic device, or a link mechanism, and can be provided not only between the lower mold 3 but also between the upper and lower molds 9 and 3.

On the other hand, a slide cam 10 is provided on the upper die 9 at a position facing the cam member 2. This slide cam 10 has a second
As shown in FIGS. 5 to 7, a negative angle molded portion 12 is formed at the lower end of the passive cam 11, and the passive cam 11
3 and a lower guide 14, and biased toward the outside of the mold by a coil spring 17 fitted and compressed into a positioning pin 16 between the seat portion 15 of the passive cam 11 and the upper mold 9. Reference numeral 18 denotes urethane rubber for cushioning the passive cam 11;
9 is a safety hanging bolt with a passive force of 1. passive cam 1
1 with respect to the lower mold 3 is achieved by carving two positioning grooves 20 on the lower surface thereof and fitting them with positioning keys 21 protruding from opposite positions of the lower mold 3.

Next, we will discuss the operation of this mold. The upper die 9 is positioned at the top dead center and the workpiece W is placed on the lower die 3. At this time, the workpiece W is in the state shown by the two-dot chain line, and the cam member 2 has been rotated backward by the automatic return device 5 to the state shown by the two-dot chain line. The upper mold 9 begins to descend, and first, the lower surface of the passive cam 11 contacts the rotating plate 8 without interfering with the negative angle molded part 4 of the cam member 2, and the cam member 2 is rotated clockwise in FIG. When the upper mold 9 continues to descend after rotation, the passive cam 11, which is biased toward the outside of the mold, resists the biasing force of the coil spring 17 and moves laterally, to the left in FIG. 2, by the action of the cam. 2, the negative angle forming portion 4 of the rotated cam member 2 and the negative angle forming portion 12 of the slide cam 10 form the workpiece W into a negative angle. After negative angle molding, the upper die 9 begins to rise. The passive cam 11 is urged outward from the mold by a coil spring 17, and moves to the right in FIG. 2 and rises without interfering with the negative angle molded workpiece W. On the other hand, since the restrained passive cam 11 rises, the cam member 2 is rotated to the left in FIG. 2 by the automatic return device 5.
The state shown by the dashed dotted line is reached, and when the negative-angle molded workpiece W is taken out from the lower mold 3, the workpiece W can be taken out without interfering with the square bottom molded part 4 of the cam member 2.

FIG. 8 shows another example of a mold for a front door trim base, which is a sheet metal part of an automobile.

Symbol W is a workpiece, 101 is a groove, 102 is a cam member, 10
3 is a lower mold, 104 is a negative angle molded part of the cam member 102, 10
5 is an automatic return device, 106 is a coil spring, 107
108 is a rotating plate, 110 is a slide cam, 111 is a passive cam, 112 is a slide cam 1
10 is a negative angle molded portion, 115 is a seat portion, 116 is a positioning pin, and 117 is a coil spring.

In the above embodiments, the sheet metal parts of automobiles are described as thin sheet products, but the present invention is not limited thereto, and can be applied to methods and molds for forming all kinds of thin sheets, such as other sheet metal products and plastics. Further, in the above embodiment, an example was described in which a rotating cam member was provided on the lower mold and a slide cam was provided on the upper mold, but it is also possible to provide a rotating cam member on the lower mold and a rotating cam on the upper mold. It goes without saying that it can be done. Furthermore, the pressing direction of the present invention is applicable not only to the vertical direction but also to those that are processed in any direction such as the horizontal direction or the diagonal direction. In the above embodiment, the cam of the upper die slides or rotates relative to the rotating cam member of the lower die to form a negative angle, but the cam member rotating to one die slides or rotates to the other die. It can be applied to bending types, hemming types, torsional bending types, etc. in which a spring bank is prevented by providing an operating part that does not move. In short, it processes thin plates by converting the linear motion of the press into rotational motion, and can be widely applied not only to negative angle forming, but also to forming, bending, special forming, drilling, drawing, and other thin plate processing.

The present invention converts linear motion into rotational motion as described above to process a negative angle formed part, and is suitable for negative angle forming processing of thin plate products, especially when the negative angle part is large, and ,
Processing is possible even when the thin sheet product is narrow and has an elongated frame shape with a three-dimensional curved surface. In addition, since the cam member is rotated, there is no need to divide or remove parts to prevent interference, and the mold has sufficient strength, making it possible to perform strong bottom punching. etc., there is no need to make any corrections after processing, the product accuracy is greatly improved, and there are no problems when the product is assembled. The mold also has sufficient strength, so there is almost no need for repairs like with conventional slide cams. Furthermore, conventional slide cam molds were installed on the sides of the product placement section of the lower die, requiring a large area, but this mold has a cam member placed directly on the workpiece placement section, making it possible to The area of the mold is small and compact, the mold is lightweight, and costs are extremely reduced.

[Brief explanation of drawings]

The drawings show specific embodiments of the present invention; Fig. 1 is a perspective view of a front pillar outer of an automobile processed using this mold, Fig. 2 is a vertical cross-sectional view of the mold, and Fig. 3 is a lower mold thereof. A plan view, FIG. 4 is a top view of the upper mold, FIG. 5 is a side view of the slide cam section, FIG. 6 is a VI-VI sectional view of FIG. 5, and FIG.
FIG. 8 is a longitudinal sectional view of a front door trim base of a sheet metal part for an automobile according to another embodiment. 3.103...Lower mold (first mold) 9.109...Upper mold (second mold) 4.104...Negative angle molding part 2.102...Cam member 12.112... Negative angle molding part 10, 110...Slide cam (cam) 1, 101,
... Groove 5 105 ... Automatic return device Applicant Uemura Metal Industry Co., Ltd. Agent Yoshiteru Takagi Figure 6 17 \・ Kazuno \ Figure 7

Claims (1)

[Scope of Claims] (11) A molding method having a molding part that forms a negative angle when a second mold is moved in a linear direction to a first mold to collide with each other to form a negative angle. A cam member having a negative angle molded portion is rotatably provided, and a cam having a negative angle molded portion is provided in a second mold so as to face the cam member, and the second mold approaches the first mold and the cam abuts against the cam member. The second mold moves away from the first mold after negative angle molding, and the cam member is rotated and retracted until the workpiece can be taken out from the first mold. (2) A method for forming a thin plate characterized by: (2) a forming die having a forming part that forms a negative angle when forming by moving a second die in a linear direction to the first die and colliding with the first die;
A cylindrical cam member with a groove carved in the axial direction of the peripheral wall is rotatably provided in a first mold, a negative angle molded portion is formed at the groove edge of the cam member, and the cam having the negative angle molded portion is attached to the cam member. An automatic return device is provided in the second mold facing the mold, and rotates and retracts the cam member until the workpiece can be removed from the first mold after molding.
A mold characterized by the fact that it is provided in a mold.