Punch for punching and punching method for punching

Abstract

To provide a punch for punching and a punching method for punching capable of surely dropping scrap from the punch by dividing shaving scrap.SOLUTION: The punch for piercing is provided with a piercing punch part 14 for piercing a prepared hole and a shaving punch part 15 for shaving the inside surface of the prepared hole, and the shaving punch part 15 has at least one shaving step in the punching direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a punch for hole punching and a punching method for hole punching. [Background technology]

[0002] Patent Document 1 describes a method for efficiently obtaining, in a single press stroke, a high-precision hole with a smooth cut surface across the entire cut edge without defects such as cracks in an Mg alloy plate produced by thixomolding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-288652 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when punching and shaving are performed in the same stroke, the shaving scrap (donut-shaped) is not properly ejected from the punch. Furthermore, when the punch rises, the scrap is lifted and rubbed against the finished surface, causing scratches on the punched and finished surfaces. Furthermore, the sliding causes heat to be generated on the finished surface, which changes the structural characteristics and causes thermal effects on the material structure. [Means for solving the problem]

[0005] In one embodiment of the punch for hole punching and the punch processing method for hole punching, a shaving step is provided in the shaving punch portion. [Effects of the Invention]

[0006] According to the punch for hole punching and the punch processing method for hole punching of the present disclosure, the shaving scrap can be divided so that the scrap can be reliably dropped downward from the punch. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing an example of a burring method according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a shaving punch unit and a hole punch unit according to the first embodiment. [Figure 3] FIG. 2 is a diagram showing an example of a forming result of the burring method according to the first embodiment. [Figure 4] 1 is a graph showing the relationship between the depth of a draft surface and the hardness of the draft surface. [Figure 5] 1 is a diagram showing an example in which the burring method according to the first embodiment is applied to processing of a front lower arm. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram showing an example of a punching method for hole piercing according to a first embodiment.

[0009] First, as shown in Fig. 1(a), a metal plate 11 is sandwiched between a die 12 and a plate holder 13. Then, a punch unit 14 punches holes in the metal plate 11.

[0010] Next, as shown in FIG. 1(b), a shaving punch unit 15 having a shaving step is used to divide the shaved scrap into four pieces, which are then dropped downward. As shown in the A-A' cross section, within the shaded region, the portion that is pressed against the metal sheet 11 first by the shaving step is the leading edge, and the portion that is pressed against the metal sheet 11 last by the shaving step is the trailing edge. In this way, the portion that is pressed against the metal sheet 11 first by the shaving step in stages is the leading edge. In this way, the shaving punch unit 15 presses against the metal sheet 11 in stages, thereby dividing the scrap portions of the metal sheet 11.

[0011] Then, as shown in FIG. 1(c), the hole in the metal plate 11 is enlarged by a burring punch 16 while being stretched into a cylindrical shape.

[0012] The shaving step is indicated by a step h on the surface where the shaving punch portion 15 contacts the metal plate 11, as shown in Figure 1(d). This shaving step h is desirably equal to or greater than the thickness of the metal plate 11. As shown in Figure 1, the punch for hole punching comprises at least a hole punch portion 14 that opens a pilot hole, and a shaving punch portion 15 that scrapes the inner surface of the pilot hole, and the shaving punch portion 15 has at least one shaving step in the punching direction.

[0013] Fig. 2 is a diagram showing an example of a punch according to the first embodiment. Fig. 2 shows a shaving punch portion 15 for shaving, which is divided into four parts. In Fig. 2, a predetermined direction of the plane on the contact surface of the metal plate 11 is defined as 0°, which serves as a reference.

[0014] Shaving to separate into four parts involves processing two areas, 90°-180° and 270°-360°, and immediately after this shaving process is completed, processing is continued in two other areas, 0°-90° and 180°-270°0° (=0°). This process produces shaved scrap divided into four parts. The shaving step must be equal to or greater than the material thickness t.

[0015] Next, the forming results will be explained. FIG. 3 is a diagram showing an example of the forming results of the punch processing method for hole punching according to the first embodiment. FIG. 3 is a schematic diagram of a photograph of the actual forming results. Compared to the forming result 41 of the conventional method, the forming result 42 of the punch processing method of the present disclosure shows a 1.6-fold improvement in formability. Note that 43 shows scrap pieces divided into four by shaving placed on a punched metal plate.

[0016] Next, the reason for the improvement in formability will be explained. Figure 4 is a graph showing the relationship between the depth of the punched surface and the hardness of the punched surface. In Figure 4, the horizontal axis represents the depth of the punched surface, and the vertical axis represents the hardness (Hv) of the punched surface. In the punched state, the hardness is increased compared to the base material. In contrast, in the shaved state, the hardness is decreased compared to the punched state. In other words, the work-hardened layer of the punched surface is removed by shaving.

[0017] Next, an example of applying the punching method for hole punching to the processing of a front lower arm will be described.

[0018] FIG. 5 is a schematic diagram showing an example in which the punch processing method for hole punching according to the first embodiment is applied to processing of a front lower arm.

[0019] First, the metal blank 51 to be processed is placed as shown in Figure 5(a). Next, as shown in Figure 5(b), the blank is punched into the shape shown in bold at 52. Then, as shown in Figure 5(c), holes are punched and shaved at two locations shown in bold at 53-1 and 53-2. Then, as shown in Figure 5(d), burring is performed at two locations 54-1 and 54-2. Finally, as shown in Figure 5(e), the outer periphery 55 is flanged.

[0020] As described above, the punch for hole punching and the punching method for hole punching disclosed herein can reliably drop scrap from the punch by dividing the shaving scrap. Furthermore, the punch for hole punching and the punching method for hole punching disclosed herein improves formability. Furthermore, the punch for hole punching and the punching method for hole punching disclosed herein can prevent scratches on the punched surface and the finished surface. Furthermore, the punch for hole punching and the punching method for hole punching disclosed herein can prevent heat generation on the finished surface, which can change the structural properties and cause thermal effects on the material structure.

[0021] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention. For example, the number of shaving steps provided in the shaving punch portion may be one or more. [Explanation of symbols]

[0022] 11 Metal plate 12 Die 13 Plate holder 14 Punch section 15 Shaving punch section 16 Burring punch section

Claims

1. A hole punch section for making pilot holes, a shaving punch portion that shaves the inner surface of the pilot hole; The shaving punch portion has at least one shaving step in the punching direction.

2. 2. The punch for hole punching according to claim 1, wherein the shaving step is equal to or greater than the thickness of the material plate.

3. 3. The punch for piercing according to claim 1, wherein the number of the shaving steps is plural.

4. A hole is punched into the metal plate using a hole punching section that opens pilot holes. A punching method for hole punching, which shaves using a shaving punch part having at least one shaving step in the punch direction and shaving the inner surface of the prepared hole.

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