JPH0152089B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention is directed to a die having a bottomed die hole and a work piece being pressed between the die hole to form a concave portion or a convex portion. The present invention relates to a press molding device including a punch for punching.

(2) Prior Art Conventionally, in such a mold device, a punch 4' as shown in FIG. 3 and a die 2' having a die hole 7' are used.
Pressing is performed to form concave or convex portions on the workpiece 3'.

(3) Problems to be solved by the invention However, in the above-mentioned conventional method, tensile stress acts on the outer portions of the bent portions 3a' and 3b' of the workpiece 3' along the radius of curvature. Surface distortion occurs due to spring back due to

The present invention has been made in view of the above circumstances, and provides a press working mold device that can avoid tensile stress from acting on the bent portion of a workpiece and prevent surface distortion from occurring. The purpose is to

B. Structure of the Invention (1) Means for Solving Problems According to the present invention, the punch has an outer surface and a tip surface facing the inner surface and bottom surface of the die hole, respectively, in order to press the workpiece with a constant thickness. A working part having a thickness smaller than the certain thickness is formed integrally with the distal end side of the base, and between the inner surface and the bottom of the die hole and the peripheral edge of the distal end of the working part. A first inclined surface that slopes inward toward the bottom side is provided to pinch the bent portion of the workpiece with the wall thickness, and the outer peripheral surface of the punch has the constant wall thickness between the opening edge of the die hole and the outer peripheral surface of the punch. A second inclined surface that pinches the bent portion of the workpiece with a thickness smaller than that of the second inclined surface is provided between the base portion and the action portion so as to be inclined outward toward the base portion.

(2) Action When pressing a workpiece with a punch and die, there is a gap between the tip edge of the punch and the first sloping surface, and between the opening edge of the die hole and the second sloping surface, as well as the inner surface and bottom surface of the die hole. , the bent portion of the workpiece is pinched with a thickness smaller than the constant thickness between the outer surface of the action portion and the tip surface of the punch.

(3) Embodiment An embodiment of the present invention will be explained below with reference to the drawings. First, in FIG.
is for pressing the outer panel of an automobile door, for example, and in order to form a recess for attaching a handle to the outer panel of the door, a die 2 and a flat plate-shaped plate are formed in cooperation with the die 2. It includes a punch 4 for pressing the work 3, and a pad 5 arranged around the punch 4 to press the work 3 against the surface of the die 2.

The die 2 is fitted and fixed to a fixed lower die 6, and includes a square die hole 7 with a bottom for forming the recess. Moreover, on the bottom surface 13 of the die hole 7,
An air vent hole 8 provided in the die 2 and extending vertically is opened, and this air vent hole 8 communicates with an air vent hole 9 provided in the lower mold 6.

The punch 4 is basically formed into a rectangular prism shape corresponding to the die hole 7, and is fixed to an upper die (not shown). Further, the pad 5 is supported by the upper mold so as to be vertically movable relative to the punch 4, and is biased downward by a spring. Therefore, as the upper die descends, pad 5 first moves to die 2.
It comes into contact with the workpiece 3 above, and the workpiece 3 is held between the pad 5 and the die 2.

In FIG. 2, according to the invention, punch 4
The operating portion 11 is integrally connected to the distal end side of the base portion 10. Moreover, this acting part 11 is for pinching the workpiece 3 between the inner surface 12 and the bottom surface 13 of the die hole 7, and when the punch 4 is lowered to the maximum extent, the outer surface 14 of the acting part 11 and the die The inner surface 12 of the hole 7, the tip end surface 15 of the action portion 11, and the bottom surface 13 of the die hole 7 face each other so as to clamp the workpiece 3 therebetween with a constant thickness d1.

Furthermore, in the die hole 7, a first inclined surface 16 is provided between the inner surface 12 and the bottom surface 13, which is inclined inward toward the bottom surface 13 side. Moreover, this first inclined surface 16 and the tip edge 17 of the punch 4 face each other so as to pinch the bent portion 3a of the workpiece 3 with a thickness d2 smaller than the constant thickness d1.

Furthermore, a second inclined surface 18 is provided on the outer circumferential surface of the punch 4 between the action portion 11 and the base 10 and is inclined outward toward the base 10 side. This second inclined surface 18 and the opening edge 19 of the die hole 7 face each other so as to pinch the bent portion 3b of the workpiece 3 with a thickness d3 smaller than the constant thickness d1. This wall thickness d3 may be equal to or different from the wall thickness d2.

Next, to explain the operation of this embodiment, during press working, the punch 4 and the pad 5 are
When the pad 5 and the die 2 are at the upper limit position, the workpiece 3 is positioned and placed on the die 2 and the lower mold 6, and then the pad 5 and the die 2 are lowered by lowering the upper mold.
A workpiece 3 is held between them, and a recess is formed in the workpiece 3 by the action of the punch 4 and die hole 7.

During such press working, the two bent portions 3a and 3b of the workpiece 3 are formed on the first inclined surface 16 and the tip edge 1.
7, as well as the second inclined surface 18 and the opening edge 19
In between, the walls are compressed with wall thicknesses d2 and d3 that are smaller than the constant wall thickness d1 in other parts. For this reason,
Tensile stress is reduced by compression in the outer portions of each bent portion 3a, 3b along the radius of curvature.
Thereby, the occurrence of spring back is avoided as much as possible, and therefore the occurrence of surface distortion is prevented as much as possible.

In the above embodiments, the mold device 1 for forming concave portions on the workpiece 3 has been described, but forming convex portions is also performed in the same way, and the mold device 1 for forming convex portions on the workpiece 3 is described. It goes without saying that the present invention can be applied to devices.

C. Effects of the Invention As described above, according to the present invention, the bent portion of the workpiece is formed between the first inclined surface of the die hole and the tip edge of the punch, and between the second inclined surface of the punch and the opening edge of the die hole. Since the pressure is applied to a thickness smaller than that of other parts, the residual tensile stress in the bent part is reduced, and the occurrence of surface distortion due to spring back is prevented as much as possible.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, and FIG. 1 is a vertical sectional view of the main part of a mold device;
FIG. 2 is an enlarged view of a portion of FIG. 1, and FIG. 3 is a sectional view corresponding to FIG. 2 to show the prior art. 1... Mold device, 2... Die, 3... Workpiece,
4...Punch, 7...Die hole, 10...Base, 1
1...Action part, 12...Inner surface, 13...Bottom surface,
14... Outer surface, 15... Tip surface, 16... First
Inclined surface, 17... tip edge, 18... second inclined surface,
19...Opening edge.

Claims (1)

[Claims] 1. In a press molding device comprising a die having a bottomed die hole and a punch for forming a concave or convex portion by pressing a workpiece between the die hole, the punch holds the workpiece at a certain level. In order to apply pressure with a thick wall, an action part having an outer surface and a tip surface facing the inner surface and bottom surface of the die hole, respectively, is integrally connected to the tip side of the base, and A first inclined surface is provided between the bottom surfaces and the peripheral edge of the tip of the acting portion, the first inclined surface being inclined inward toward the bottom surface in order to pinch the bent portion of the workpiece with a thickness smaller than the constant thickness. A second inclined surface is provided on the outer circumferential surface of the punch for pinching the bent part of the workpiece with a thickness smaller than the constant thickness between the opening edge of the die hole and the second inclined surface is provided on the base side between the base and the acting part. 1. A press working mold device, characterized in that it is installed so as to be inclined outward as it goes toward.