Press working method and progressive press working device

Abstract

To provide a press working method that can beautifully finish a compressed surface provided with through holes. [Solution] The press processing method is used to produce a part 40 having a through hole 29 formed in a compressed surface 36, and includes a first step P10 of drawing a metal plate, a second step P20 of punching out an area 16 including a protrusion on the metal plate formed in the first step, and a third step P30 of compressing and thinning a predetermined area including a hole 26 formed in the second step.

Description

[Technical Field]

[0001] The present invention relates to a press working method and a progressive press working apparatus, and more particularly to a press working method and a progressive press working apparatus that involve punching and compression working. [Background technology]

[0002] Conventionally, compression processes such as coining are used in press working. In compression processes, a press is used to locally apply pressure to a metal plate, causing the material to flow and plastically deform into a desired shape.

[0003] Compression can also be used to create thin-walled sections where the thickness is reduced in parts. Pressing, unlike cutting, has the advantage that the metal's streaks are not easily cut by the process, so high strength is maintained even in thin-walled sections.

[0004] In addition to compression, press working can also perform various other processes such as shearing processes such as hole punching and outline punching, bending, drawing, etc. In addition, press machines for progressive press (or transfer press) working, which are configured to perform a combination of these processes sequentially, are widely used.

[0005] In progressive press working, the metal plate material is moved at a predetermined pitch so that each processing section can perform a different process. Progressive press working equipment typically uses a mold in which each processing section is arranged at a uniform pitch, and by using this to automatically perform various processes in sequence, it is possible to mass-produce parts with complex shapes.

[0006] In progressive press working, by combining hole punching and compression working, it is possible to mass-produce parts with a shape in which a hole is drilled in the center of a circular thin-walled part (a shape with a doughnut-shaped thin-walled part), for example.

[0007] Patent Document 1 discloses a technique for forming a recess (thin portion) as a countersunk hole around a central through hole. Such a part is used, for example, as a bolt fixing portion for a cable connection in an electrical device. Patent Document 2 also discloses a technique for forming a through hole with a tapered countersunk hole in a single process by using a single punch with a protrusion, cutting edge, and tapered portion when forming a countersunk hole for a countersunk screw by press working. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-314925 [Patent Document 2] Japanese Patent Application Publication No. 7-032064 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-7253 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the inventors of the present application have discovered that when parts with holes in thin-walled portions as described above are produced by press working, the compressed surface may not be finished neatly, particularly when small parts are produced, simply performing compression and drilling, as has been done in the past.

[0010] The present invention has been made in consideration of the above-mentioned problems, and its main object is to provide a press working method that can neatly finish the compressed surface of a hole, and a progressive press working device for realizing this method. [Means for solving the problem]

[0011] A press processing method according to an embodiment of the present invention is used to produce a part having a through hole formed in a compressed surface, and includes a first step of drawing a metal plate, a second step of punching out an area on the metal plate that includes a protrusion formed in the first step, and a third step of compressing and thinning a predetermined area that includes the hole formed in the second step.

[0012] In one embodiment, the press working method further includes a fourth step of punching a main hole having a diameter larger than that of the hole formed in the second step in the compressed surface formed in the third step.

[0013] In one embodiment, in the first step, a protrusion is formed that protrudes in a first direction from the front surface of the metal plate toward the back surface, in the second step, punching is performed in the same direction as the first direction, and in the third step, a die corresponding to the specified area is applied from a second direction opposite to the first direction, thereby forming a recess as a compression processing area on the back surface side of the metal plate.

[0014] In one embodiment, the diameter of the hole formed in the second step is larger than the diameter of the tip of the hole formed in the drawing step in the first step, and the diameter of the hole formed in the compression step in the third step is larger than the diameter of the hole formed in the second step.

[0015] A progressive press processing device according to an embodiment of the present invention is configured to include, in order from the upstream side, a drawing processing section that performs drawing on a metal plate, a pilot hole drilling section that punches out an area including a protrusion on the metal plate formed in the drawing processing section, a compression processing section that compresses and thins a predetermined area including a pilot hole formed by the pilot hole drilling section, and a main drilling section that actually drills an area including the pilot hole in the compressed surface formed in the compression processing section. [Effects of the Invention]

[0016] According to the press working method or progressive press working apparatus of the embodiment of the present invention, it is possible to efficiently manufacture a part having a good compressed surface and having a shape with holes in the surface. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing a main part of a stamping device according to an embodiment of the present invention. [Figure 2] 3A to 3C are plan views showing metal plates formed in the respective processing sections of the stamping device according to the embodiment of the present invention. [Figure 3] 1A and 1B are diagrams showing a metal plate as an example of a part formed using a stamping device according to an embodiment of the present invention, in which (a) is a plan view and (b) is a cross-sectional view. [Figure 4] 1 shows a punch and die for performing compression in a pressing device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments.

[0019] 1 shows the main components of a press apparatus 100 according to an embodiment of the present invention. The press apparatus 100 is a progressive press apparatus, and different press processes are performed in each process section. In the press apparatus 100 shown in the figure, workpieces are transferred sequentially at a predetermined pitch from right to left in the figure through a press space 50C between an upper mold 50A and a lower mold 50B that constitute a mold.

[0020] The workpiece here is a strip-shaped metal plate, and the material is, for example, aluminum, copper, iron, etc. However, the material is not limited to these, and the press device 100 can process metal and alloy plate materials made of various materials. The metal plate has a thickness of, for example, about 1 mm to 5 mm.

[0021] 1, the press machine 100 of this embodiment includes a compression processing section (coining section) 30 for forming a thin-walled section, a first hole punching section 20 for drilling pilot holes (temporary through holes) before the compression processing section 30, and a drawing processing section 10 for performing drawing before the first hole punching section 20. A mold provided with a punch and a die according to the type of processing to be performed in each processing section is used. Note that, for convenience, the part attached to the upper die of the mold will be referred to as the punch, and the part attached to the lower die will be referred to as the die.

[0022] Specifically, the drawing section 10 is composed of a punch 12 with rounded corners at the tip and a die 14 with a receiving portion that fits the shape of the punch. The first perforating section 20 is composed of a punch 22 for perforating and a matching die 24. The compression section 30 is composed of a punch 32 for pressing the metal plate from above and a die 34 configured to receive from below a specific back surface region of the metal plate pressed by the punch.

[0023] Although only some of the processing units related to the invention will be described here, it goes without saying that the press device 100 may include other types of processing units. For example, the press device 100 may include a processing unit for performing outer diameter punching, a processing unit for providing notches, and a processing unit for drilling holes in locations other than thin-walled portions.

[0024] Furthermore, as will be described later, the press machine 100 produces parts having holes in the compressed surface. For this reason, although not shown, the press machine 100 is preferably provided with a second drilling section (main drilling section) downstream of the compression section 30 for punching holes with diameters set within the tolerance range.

[0025] FIG. 2 is a plan view showing a metal plate (component) that has undergone a series of processes in each processing section of a press processing device according to an embodiment of the present invention, where FIG. 3(a) is a plan view showing a metal plate that shows an example of a formed component, and FIG. 3(b) is a cross-sectional view thereof.

[0026] 2, like Fig. 1, shows a state in which each process P10, P20, P25, and P30 is performed on part 40 in order from right to left in the figure. Also, in Fig. 2, part 40 is shown in a separated state in each process, but in reality, the parts are transferred at a predetermined pitch while remaining connected in the progressive press, and are finally separated into individual parts by shearing processes such as outline punching and cutting.

[0027] As shown in Fig. 2, first, in a drawing process P10, a predetermined region of a metal plate that will become a part 40 is drawn. As a result, a protrusion (or recess) 16 is formed in the part. The protrusion 16 is formed to fit the shape of the punch of the drawing section 10, and in this embodiment, the tip is formed as a protrusion with a roughly hemispherical shape (however, the very tip is a circular flat surface).

[0028] The diameter D1 of the base of the protrusion 16, which is the outer diameter of the drawn region, is typically set to be equal to or smaller than the diameter D3 of the compressed portion (coined portion) described below, for example, 8 mm to 14 mm. The diameter D1' of the tip of the protrusion 16 is set to be, for example, 6 mm to 10 mm. The depth of the protrusion 16 (the distance from the metal plate surface to the deepest part in the central region of the protrusion) is set to be, for example, 3 mm to 8 mm.

[0029] Next, in a pilot hole drilling process P20, a hole is punched in the drawn portion 26. As a result, a pilot hole 28 is formed as shown in an idling process P25. In this embodiment, the pilot hole 28 has a circular shape. The diameter D2 of the pilot hole 28 is typically set to be approximately equal to the diameter D1 of the base of the protrusion 16 and larger than the diameter D1' of the tip end of the protrusion 16, for example, 7 mm to 13 mm. However, the size of the pilot hole 28 may be selected appropriately depending on the size of the actual hole to be finally formed.

[0030] At this time, most of the protrusion 16 formed in the drawing step P10 is punched out. However, because the drawing step P10 has been performed in advance, the metal of the protrusion 16, particularly near the base, is stretched and thinned. As a result, the pilot hole 28 is formed with a thinner wall, particularly in the peripheral area, compared to when the drawing process is not performed in advance.

[0031] Next, in a compression process P30, compression is performed on a predetermined area larger than the pilot hole 28, and a compression region 36 (or a compression surface 36) is formed around the pilot hole 28. In this embodiment, the compression region 36 is circular. The diameter D3 of the compression region 36 is, for example, 10 mm to 20 mm, which is, for example, about 1.1 to 2 times the diameter D2 of the pilot hole 28.

[0032] At this time, since the peripheral wall of the pilot hole 28 has been thinned by previously performing the drawing step P10, the amount of metal that flows toward the center of the pilot hole due to the compression process is relatively small. This allows the compression process (thinning) that involves reducing the diameter of the pilot hole 28 to be carried out relatively smoothly and uniformly. As a result, the surface of the compression-processed surface 36 can be finished in a clean condition.

[0033] 1, the compressed surface 36 is formed on the back side, that is, on the side of the protrusion 16 formed by drawing or on the opposite side to the punching direction of the pilot hole drilling on the top surface. By compressing from the back side in this way, a pressing force acts from the top surface to the back surface in the previous process, causing some curvature toward the back surface and flow of metal, but this is compressed and pressurized in a direction that restores this. This makes it possible to make the compressed surface 36 cleaner.

[0034] Through these steps, a part 40 is obtained using the press device 100, as shown in Figures 3(a) and 3(b). The part 40 has a thin-walled portion 42 having a circular compressed surface 36 formed by compression, and a main hole 44 provided in the center of the thin-walled portion 42.

[0035] When the plate thickness is about 2 mm, the compression depth (coining depth) and the thickness of the thin-walled portion 42 are, for example, about 1 mm, and the diameter D3 of the compression processed region 36 is about 17 mm.

[0036] Main hole 44 is formed by punching after compression, and its diameter D4 is, for example, 8 mm to 12 mm. Main hole drilling is performed by punching out a doughnut-shaped hole around the pilot hole whose diameter was reduced during compression, but because the amount of punching is small, main hole 44 is formed according to the designed dimensions within the tolerance range. Furthermore, the surrounding compressed surface 36 is also obtained in a clean state with little dullness, resulting in a high-quality part 40.

[0037] 4 shows a detailed configuration of the compression processing unit 30 included in the press device 100 of this embodiment. As shown in the figure, a recess 32a is provided in the central region of the lower surface of the punch 32, and a recess 34a is provided in the central region of the upper surface of the die 34.

[0038] In this way, by forming a relief portion for the metal in the central region during compression, the metal can easily flow inward, resulting in smooth compression. This makes it possible to make the compression-processed surface 36 cleaner.

[0039] Although the progressive stamping apparatus and stamping method according to the embodiment of the present invention have been described above, various modifications are possible without departing from the spirit of the present invention. For example, although the above describes an embodiment in which a part having a circular compressed region and a circular central through hole is manufactured, the present invention is not limited to this and can be applied to the manufacture of parts having compressed regions and central through holes of various shapes. [Industrial Applicability]

[0040] The press working method and progressive press working device according to the embodiment of the present invention are suitably used when performing a plurality of processes, in particular, punching and compression, on the same part. [Explanation of symbols]

[0041] 10 Compression processing section 12 Punch 14 Die 16 Drawing area 20 Pre-drilling section 22 Punch 24 Die 28 Pilot hole 30 Compression Processing Section 32 Punch 34 Die 36 Compression Processing Area 40 parts 42 Thin-walled section 44 holes 100 Press processing equipment

Claims

1. A press working method for producing a part having a through hole formed in a compressed surface, comprising: a first step of drawing a metal plate by sandwiching the metal plate between a punch having a convex tip and a die having a receiving portion having a concave tip; a second step of punching out an area including the protrusion on the metal plate formed in the first step using another punch and die for drilling a pilot hole; a third step of compressing a predetermined region including the hole formed in the second step without closing the hole to thin the region, thereby forming a recess including a compressed surface parallel to the plate surface of the metal plate; A fourth step is to punch a hole with a diameter larger than that of the hole formed in the second step on the compressed processed surface formed in the third step, and at this time, the periphery of the pilot hole is punched out in a donut shape. Including, A press processing method in which, in the first step, a protrusion is formed that protrudes in a first direction from the front surface of the metal plate toward the back surface, in the second step, punching is performed in the same direction as the first direction, and in the third step, a die corresponding to the specified area is applied from a second direction opposite to the first direction, thereby forming a compressed surface parallel to the plate surface of the metal plate on the back surface side of the metal plate.

2. 2. The press working method according to claim 1, wherein the diameter of the hole formed in the second step is larger than the diameter of the tip of the drawing step in the first step, and the diameter of the hole formed in the compression step in the third step is larger than the diameter of the hole formed in the second step.

3. A press processing method as described in claim 1 or 2, wherein the surfaces of the die used in the third step and the punch opposing it are each provided with a recess as an escape area for metal.

4. a drawing unit that performs drawing on a metal plate by sandwiching the metal plate between a punch having a convex tip and a die having a receiving portion having a concave tip; a pilot hole punching section that punches out an area including a protrusion on the metal plate formed in the drawing section using another punch and die for pilot holes; a compression processing unit that compresses and thins a predetermined region including the pilot hole formed by the pilot hole drilling unit without closing the hole, and forms a recess including a compression processing surface parallel to the plate surface of the metal plate; a main hole punching section that punches a region including the pilot hole on the compressed surface formed in the compression processing section in a donut shape around the pilot hole; are configured to include, in order from the upstream side, a progressive press processing device configured such that the drawing processing unit forms a protrusion that protrudes in a first direction from the front surface of the metal plate toward the back surface, the pilot hole punching unit punches pilot holes in the same direction as the first direction, and the compression processing unit applies a die corresponding to the specified area from a second direction opposite to the first direction, thereby forming a compression processed surface parallel to the plate surface of the metal plate on the back surface side of the metal plate.

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