JP7128553B1 - Metal stamping method. - Google Patents

Abstract

The present invention provides a metal press working method that has a high degree of freedom in product design, is excellent in mass productivity with a small number of processes, and is low-cost and suitable for small lots and a wide variety of products.
The method includes a first extrusion step of forming an extruded portion in a plate thickness direction of a metal plate-shaped material, and a second extrusion step of extruding the extruded portion backward in an extrusion direction side, wherein the first extrusion step is performed. A processed product having a thickness greater than the thickness of the material plate is manufactured by the extrusion process of (1) and the second extrusion process.
[Selection drawing] Fig. 2

Description

The present invention relates to a metal press working method.

Conventionally, as a metal collar manufacturing method, which is one type of this type of press working method, for example, a ring-shaped sheet metal shown in Patent Document 1 is welded by electromagnetic induction heating, and then both end surfaces are butted in the circumferential direction. Metal collars are known which are joined by, for example, laser welding.

On the other hand, as shown in Patent Document 2, for example, a metal plate with a predetermined thickness is punched into a disk shape, and the metal plate punched into a disk shape is drawn into a cup shape in several steps, and the bottom is removed and the edge is drawn. A method of manufacturing a collar is described.

JP 2014-163398 A JP 2016-6331 A

The method disclosed in Patent Literature 1 requires electromagnetic induction heating and laser welding after rounding the plate by press working, requiring a long process and large-scale equipment, making it difficult to reduce costs.

The method of making a metal collar by punching the bottom of the drawn product and trimming the edges of the flange after drawing disclosed in Patent Document 2 requires, for example, transfer molding. The transfer press is suitable for mass production of a single size, but it has the problem that it is not suitable for small-lot, high-mix production because it requires a mold change for all processes in order to change the size. The thickness of the collar was limited to a certain range in the direction in which the thickness decreased by drawing from the thickness of the material plate, and the degree of freedom in design was low.

To solve these problems, to provide a metal press working method and a metal press work product which have a high degree of freedom in product design, are excellent in mass productivity with a small number of processes, and are suitable for low-volume, high-variety production at low cost.

The press working method of the present invention includes a first extrusion step of forming an extruded portion in a thickness direction of a metal plate material, and a second extrusion step of extruding the extruded portion backward in the extrusion direction. a processed product that is thicker in the plate thickness direction than the metal plate material is manufactured by the first extrusion step and the second extrusion step;

In the press working method of the present invention, in the first extrusion step of forming the extruded portion in the plate thickness direction, the metal plate material is extruded with the outer diameter D of the pressed product, and the extruded portion is pushed backward in the extrusion direction side. In the second extruding step of extruding, the inner diameter d of the pressed product is extruded backward to the height H.

In the press working method of the present invention, in the first extrusion step of forming the extruded portion in the plate thickness direction, the metal plate material is extruded with the inner diameter D of the die and extruded backward in the extrusion direction side with respect to the extruded portion. In the extruding step 2, a pressed product having an outer diameter D, an inner diameter d, and a height H is formed by extruding backward with an outer diameter d of a backward extruding punch to obtain a height H.

In the press working method of the present invention, the thickness t of the pressed product obtained by subtracting the inner diameter d of the pressed product from the outer diameter D of the pressed product and dividing by 2 is smaller than the plate thickness T of the metal plate material.

The press working method of the present invention includes a first extrusion step of forming an extruded portion in a thickness direction of a metal plate material, and a second extrusion step of extruding the extruded portion backward in the extrusion direction. , by the first extrusion step and the second extrusion step, a processed product that is thicker in the plate thickness direction than the plate thickness of the metal plate material is produced, the bottom of the processed product is punched, and the inner diameter and / or the outer diameter is Install screws.

INDUSTRIAL APPLICABILITY A method for processing a pressed product and a pressed product using the press working method of the present invention can easily change the shape and dimensions, and are inexpensive and suitable for high-mix low-volume production.

The pressed product using the press working method of the present invention can produce the screw thread necessary for screw fastening in a small number of processes by press working even if the thread length required for screw fastening is insufficient in the material plate thickness. You can make ribs that can be processed in numbers.

Metal collar perspective view, front view and cross-sectional photograph of the first embodiment of the present invention Schematic diagram of the process of the first embodiment of the present invention FIG. 2 is a cross-sectional view of a main part of the process of the first embodiment of the present invention; FIG. 2 is a cross-sectional view of the essential part of the first extrusion step of the present invention; FIG. 4 is a cross-sectional view of the main part of the second extrusion process of the present invention; Graph of plate thickness increase rate by metal collar inner diameter and indentation depth Graph of indentation depth and plate thickness increase rate of metal collar for the same mold A cross-sectional view of a modification of the first extrusion process of the present invention Modifications of Inventive Metal Collar Shape A perspective view and a front view of a pressed product in the second embodiment. The perspective view of the 1st extrusion process product of 2nd Embodiment. The perspective view of the 2nd extrusion process product of 2nd Embodiment. Sectional view of the second extrusion process product of the second embodiment Cross-sectional view of the bottoming process product of the second embodiment Sectional view of the tap processed product of the second embodiment Sectional view of the washer-welded product of the second embodiment

A first embodiment of the present invention will be described below. FIG. 1(a) shows an external perspective view of the metal collar 1 of the first embodiment. FIG. 1(b) shows a front view of the metal collar 1 of the first embodiment. The metal collar 1 is cylindrical, and the metal collar height H is greater than the wall thickness t. The inner and outer diameter entrances of the metal collar 1 are chamfered 11, 12 to improve the workability when incorporating it into a device or the like. The material can be selected from iron and steel materials, stainless steel, aluminum and aluminum alloys, copper and copper alloys, and other non-ferrous metals, depending on the application.

FIG. 2 shows a schematic diagram of the process of the first embodiment, and FIG. 3 shows a cross-sectional view thereof. Half blanking is performed on the plate material 100 in the first extrusion process 20 . In the first extrusion step 20, the outer diameter Dp of the first extrusion punch is larger than the diameter D of the first extrusion portion 21, and configured with a negative clearance. It's not supposed to. A thin portion 26 is formed by the negative clearance. The material of the thin portion 26 has poor fluidity due to work hardening. The pushing depth L1 of the first pushing portion 22 is preferably 50 to 95% of the plate thickness T. When the pushing depth L1 is less than 50%, the volume of the first pushing portion 21 tends to flow outward in the radial direction when pushing backward in the second pushing step 30, and the metal collar attains a predetermined height. becomes difficult. If the pushing depth L1 of the first pushing portion 21 exceeds 95%, the working stress increases, and the pushing punch and die (not shown) are easily damaged, shortening their life. In addition, the strength of the thin portion 26 is insufficient, and there is a concern that the thin portion may crack, cause misalignment, or fall off.

In the first extrusion step, as shown in FIG. 4 , the first extruded portion 21 is formed by the inner diameter Dd of the half-blanking die 23 , which is equal to the outer diameter D of the metal collar 1 . It means that the outer diameter D of the metal collar 1 is determined in the first extrusion process 20 , and it is possible to change the outer diameter D of the metal collar 1 by changing the inner diameter Dd of the half blanking die 23 . It has a high degree of design freedom and is suitable for small-lot, high-mix production.

A second extrusion step 30 is shown in FIGS. The second extrusion step 30 is backward extrusion, in which the outer diameter D is constrained by the stripper 33 and the bottom surface 35 is restrained by the counter punch 32, and is pushed backward by the rear extrusion punch 31 having the diameter d to obtain a predetermined collar height. Get a H. By adjusting the stroke of the pushing depth L1 of the first pushing process 20 and the backward pushing depth L2 of the second pushing process, the rear pushing punch 31 is capable of changing the height H of the metal collar with the same mold. Carbide with a mirror-finished surface.

In the second extrusion step 30, the diameter d of the rear extrusion punch 31 is equal to the inner diameter d of the metal collar 1, as shown in FIG. It means that the inner diameter d of the metal collar 1 is determined in the second extrusion process 30 , and it is possible to change the inner diameter d of the metal collar 1 by changing the diameter of the rear extrusion punch 31 . It has a high degree of design freedom and is suitable for small-lot, high-mix production.

As described above, it is possible to produce a wide variety of products by changing only a few parameters such as the tool diameter and stroke in the first extrusion process 20 and the second extrusion process 30 .

（１）式の右辺第３項の（Ｔ－Ｌ１）は、図３の底部４１の厚みを示す。押し出された高さＨ１およびＨ２は、体積一定の条件で、押し込み深さＬ１およびＬ２とプレスのツールの直径Ｄｐ，Ｄ，ｄの関数で表すことができる。

（１）式に（２）および（３）式を代入すると（４）式となる。

（４）式で、Ｄｐ＝Ｄと仮定すると下記等式が成り立つ。

本実施形態の金属カラーの加工方法は、金属カラーの内外径Ｄ，ｄと第２の押し出し工程の押し込み深さＬ２で計算された（５）式の右辺２項の厚み増加分を板状素材厚みＴにプラスした、厚みを増加させるプレス加工方法であることを示している。金属の板状素材１００の板厚Ｔに対し、第１の実施形態の金属カラー１の高さＨの厚み方向寸法増加率αは、（６）式で表される。

Design parameters of the metal collar 1 will be described. FIG. 5 shows the cross-sectional shape of the second extrusion step. The plate thickness T of the metal plate material 100 indicates that it is pushed in with the outer diameter Dp of the first extrusion punch and is pushed out with the outer diameter D of the first metal collar 1 . The second extrusion step is a backward extrusion with the inner diameter d of the metal collar 1 . Let H1 be the height extruded by the first pushing depth L1, and let H2 be the height extruded by the pushing depth L2 in the second pushing step. A height H of the metal collar 1 is represented by the formula (1).

(TL1) in the third term on the right side of equation (1) indicates the thickness of the bottom portion 41 in FIG. The extruded heights H1 and H2 can be expressed as a function of the indentation depths L1 and L2 and the press tool diameters Dp, D, d under constant volume conditions.

Substituting equations (2) and (3) into equation (1) yields equation (4).

Assuming that Dp=D in equation (4), the following equation holds.

In the metal collar processing method of the present embodiment, the increase in thickness of the second term on the right side of Equation (5) calculated by the inner and outer diameters D and d of the metal collar and the pushing depth L2 in the second extrusion process is applied to the plate-shaped material. This indicates that the press working method increases the thickness by adding to the thickness T. The rate of increase in thickness direction dimension α of the height H of the metal collar 1 of the first embodiment with respect to the plate thickness T of the metal plate material 100 is expressed by the formula (6).

FIG. 6 shows a graph of the relationship between the inner diameter d and the indentation depth L2 as parameters when the outer diameter D of the metal collar 1 is 10 mm. The thickness direction dimension increase rate α indicates how many times the thickness T of the plate material 100 can be increased in the thickness direction. The relationship between the inner diameter d and the thickness direction dimension increase rate α is shown when the indentation depth L2 is 70%, 80%, and 90% of the plate thickness under the condition that the outer diameter D is constant. It can be seen that the thickness direction dimension increase rate α varies with the inner diameter d and the indentation depth L2, and the thickness in the plate thickness direction is increased.

Similarly, FIG. 7 shows a graph of the relationship between the indentation depth L2 and the rate of increase in the dimension in the thickness direction α when the outer diameter D of the metal collar 1 is fixed at 10 mm and the inner diameter d is fixed at 7 mm. By changing L2, it is possible to manufacture a product with the same mold while changing the thickness direction dimension increase rate α. As described above, according to the method of the embodiment, it is possible to provide the metal collar 1 with a high degree of freedom in design, using the outer diameter D, the inner diameter d, and the indentation depth L2 as parameters.

A second inner diameter bottoming step 40 is shown in FIGS. The inner diameter bottom 41 is punched out with a punch (not shown) having a diameter approximately equal to the collar inner diameter d.

2 and 3 show the second outer diameter cutting step 50. FIG. A punch (not shown) having a diameter approximately equal to the outer diameter D of the collar is used to punch out the outer diameter D of the collar and separate it from the plate-like material 100 . A cross-sectional photograph of the metal collar 1 is shown in FIG. 1(c). The upper part of the metal collar is the part extruded in the first extrusion process 20, and the crystal structure of the metal with little deformation can be observed. And almost no fiber flow is observed. A fiber flow extending in the height H direction can be observed on the lower side of the metal collar 1 and on the side of the inner diameter 14 . It is assumed that the material is extruded backwards in the second extrusion step 30 and moves in the direction of increasing the height H. It can be said that this cross-sectional structure is a characteristic structure of the product manufactured by the press working method of this embodiment.

FIG. 8 shows a modification of the first extrusion process 20 of the present invention. It is not a requirement that the diameter D of the first indentation 22 is greater than the diameter D of the first extrusion 21 . The first extrusion step 20 should not cause any breakage. In FIG. 8A, the diameter of the first extruding portion 21 and the diameter of the first pushing portion 22 are the same, or the diameter of the first pushing portion is smaller. A chamfer 27 is provided at the tip of the punch 51 . The size of the chamfer is about 0.3 to 0.5. If it is less than 0.3, breakage may occur. In FIG. 8B, a fillet 28 is provided at the tip of the first extrusion punch 31 . The fillet size should be about 0.3 to 0.5. If it is less than 0.3, breakage may occur.

(a) to (g) of FIG. 9 show modifications of the shape of the metal collar 1 . The outer shape can be freely changed by changing the shape of the half-blanking die 23 in the first extrusion process 20 and the shape of the stripper 33 in the second extrusion process 30 . The inner shape can be freely changed by changing the shape of the rearward extrusion punch 31 in the second extrusion process 30 .

FIG. 9A shows an example in which the inner shape is a circle and the outer shape is a polygon. It is also possible to cut a tap on the inner diameter by post-processing, and it may be used for applications such as fastening parts and connecting shafts. The flat part can be welded for use when holding a hinge shaft. It is a convenient shape when the side of the collar is fixed and used. It is also possible to use this flat portion to lock the metal collar so that it does not rotate.

FIG. 9(b) shows an example in which the outer shape is a circle and the inner part is a polygon. It is also possible to use the flat portion to lock the metal collar against rotation.

FIG. 9(c) shows an example of an oval shape both inside and outside. For example, two shafts can be passed through the inner shape to maintain a constant relative distance between the two shafts, or one shaft can be passed through and held so as to be movable only in the longitudinal direction.

FIG. 9(d) is an example in which the outer diameter is removed leaving the bottom of the inner diameter. Can be used for containers.

FIG. 9(e) is a cross-sectional view showing a state in which only the central portion is removed when the bottom of the inner diameter is removed, leaving the flange inside. The shape allows for axial positioning of the member to be incorporated.

FIG. 9(f) is an example in which a convex portion is formed near the center of the bottom, and the outer periphery is removed without the bottom being removed. It is possible to make the convex part coaxial with the inner diameter or make it eccentric. Various usages are conceivable depending on the relative positional relationship between the inner diameter of the collar and the projection.

FIG. 9(g) shows an example with a flange. A shape with a flange can be manufactured by punching out the flange part 70 while leaving the outer circumference punched out. The inner diameter may or may not have a bottom. For example, a hole 71 is formed in the collar portion 70, and a threaded hole 72 is machined in the side surface of the cylindrical portion formed by the inner and outer surfaces 13, 14 to be used as a shaft holder.

FIGS. 10 to 16 show an example of a metal pressed product representing the second embodiment of the present invention. As shown in FIG. 10, the plate-like component 201 is provided with female screw portions 241 to 244 for fastening. A necessary number of screw threads may be required in order to secure fastening strength for fastening screws. It is an example of forming a rib for threading using the press working method of the present invention.

If the thickness of the plate-shaped component 201 does not allow the required number of threads to be secured, the press working method of the present invention can be used to form a threaded portion that is thicker than the plate thickness of the material. As shown in FIG. 11, in a first extrusion step 210, a plate-like component 201 is simultaneously half-blanked at four locations to form first extrusions 211-214.

The first extrusion step 210 preferably chamfers or fillets the punch tips with the same diameter or positive clearance to prevent breakage. That makes it easier to ensure the strength of the pressed product after completion. Of course, it goes without saying that the extrusion punch and the extrusion die may be made with a negative clearance.

Next, as shown in FIG. 12, in a second pushing step 220, the ribs 221 to 224 are pushed out from the first pushing portion 211 side. It is desirable that the punch be made of cemented carbide and have a mirror-finished surface.

FIG. 13 shows a cross section of the shape extruded in the second extrusion step 220. As shown in FIG. The first step punch has a positive clearance and a chamfer 227 at the tip. In order to prevent the material volume from moving to the outer diameter side in the second extrusion process after the first extrusion process, flow prevention grooves 228 are formed at the roots of the ribs 221 to 224 to roughen the tool surface. is also an effective method for obtaining the height of the ribs 241-244.

As shown in FIG. 14, the bottoms of 221-224 are punched, and as shown in FIG. The tap screw 251 can be formed by cutting or rolling.

The depth L1 of the first pressing portion 222 is preferably 50 to 75% of the thickness T of the material plate. If the pushing depth L1 is less than 50%, the material tends to flow to the outer diameter side of the first pushing portion 221 when pushing backward in the second pushing step 30, and the height required for cutting threads is reduced. cannot be ensured. If the push depth L1 of the first extruded portion 221 exceeds 75%, there is a concern that the screw may be broken due to lack of strength and come off when the screw is fastened.

Finally, as shown in FIG. 16, a washer 252 is joined by resistance welding to the recess formed by extrusion in the first extrusion step 210 formed on the back side. If it is necessary to flatten the back surface, polish it on both sides until it is flat. When the plate-like part 201 is screwed to another part (not shown), the washer 252 may be incorporated without welding between the plate-like part 201 and the other part.

Such a process is an epoch-making method in which the threaded ribs 241 to 244 longer than the material plate thickness T can be obtained in a short process by press working.

In the second embodiment, the press working method uses a transfer press or transfer robot transportation. Positioning is performed using shapes such as the outline of the product so that the processing position does not shift during the transfer of the first extrusion process 210 , the second extrusion process 220 and the bottoming process 230 .

Although the present invention has been described with respect to the metal collar of the first embodiment and the pressed product of the second embodiment, the application is not limited thereto, and the half blanking by the first extrusion process and the second extrusion process are performed. It is applied to all stamping methods using backward extrusion by

Reference Signs List 1... Metal collar 20... First extrusion process 21... First extrusion part 22... First pushing part 23... Half blanking die 26... Thin part 30... Second extrusion process 31... Rear extrusion punch 40... Inner diameter bottom Punching process 50...Outer diameter punching process 100...Plate material 201...Plate-like part 210...First extrusion process 220...Second extrusion step 222...First pushing part 228...Flow prevention groove 230...Bottom punching Step 252: Washer D: Outer diameter of metal collar d: Inner diameter of metal collar Dd: Outer diameter of first extrusion Dp: Outer diameter of first extrusion punch t: Thickness of collar T: Thickness of raw material H: Height of collar L1 ... depth of indentation L2 ... depth of indentation α ... dimensional increase rate in the thickness direction

Claims (4)

A manufacturing method for manufacturing a metal collar having an outer diameter D, an inner diameter d, and a height H from a metal plate-shaped material having a thickness T, wherein the metal plate-shaped material is extruded and a thin portion is formed in the plate thickness direction. In the first extrusion step, the first extrusion punch outer diameter Dp, the die inner diameter D, and the depth L1 are extruded, and the extrusion portion is pushed backward in the extrusion direction in the second extrusion step. The bottom surface and the thin portion are restrained by a counter punch, the outer diameter of the extruded portion and the thin portion are restrained by a stripper, and pushed backward with the outer diameter d of the punch and the pushing depth L2, (Dp ² /D ² ) x L1 + (d ² /(D ² -d ² ))×L2+(T−L1) to obtain a rib having a height H, and punch the bottom of the inner diameter with a punch having a diameter approximately equal to the inner diameter d of the rib in the inner diameter bottom punching step, and in the outer diameter punching step, A metal collar manufacturing method for manufacturing a metal collar having an outer diameter D, an inner diameter d, and a height H by removing the outer diameter D of the rib to a diameter approximately equal to the outer diameter D of the rib, and separating it from the plate-like material. . 2. The method of manufacturing a metal collar according to claim 1, wherein, in said first extrusion step, the plate material is extruded at a depth L1 of 50 to 95% of the thickness T of the plate material. A manufacturing method for manufacturing a rib having an outer diameter D, an inner diameter d, and a height H that is thick in the plate thickness direction and is connected to the metal plate-like material at a thin portion from a metal plate-like material having a thickness T, the method comprising: In the first extrusion step of forming an extruded portion and a thin portion in the thickness direction of a metal plate material, the first extrusion punch outer diameter Dp, the die inner diameter D, and the depth L1 are used to extrude the extruded portion. In the second extruding step of extruding backward in the extruding direction, the bottom surface of the extruded portion and the thin portion are constrained by a counter punch, and the outer diameter of the extruded portion and the thin portion are constrained by a stripper to form a backward extruding punch. Extrude backward with an outer diameter d and an indentation depth L2, (Dp ² /D ² ) x L1 + (d ² /(D ² -d ² )) × L2 + (T - L1) to obtain a rib with a height H, and in the inner diameter bottom punching step, punch the bottom of the inner diameter with a diameter approximately equal to the inner diameter d of the rib, and obtain an outer diameter D, an inner diameter d, and a height A rib manufacturing method for a plate-like pressed product for manufacturing ribs of length H. 4. The method for manufacturing ribs according to claim 3, wherein in the first extrusion step, the plate material is extruded at a depth L1 of 50 to 75% of the thickness T of the plate material.

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