JP7358608B2 - Processed product manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a workpiece made of a plated steel plate having a plating layer on its surface and having a cut end, and to the workpiece.

BACKGROUND ART In recent years, processed products made from plated steel sheets having a plating layer on their surfaces have been increasingly used as parts for equipment such as automobiles and home appliances. By using a plated steel plate as a material, surface treatment after forming the processed product can be omitted, and manufacturing costs can be suppressed. Moreover, by omitting the surface treatment after molding, it is possible to avoid deterioration of the dimensional accuracy of the part due to the surface treatment after molding. Omitting surface treatment after molding is particularly considered for parts that require high dimensional accuracy, such as motor cases.

If surface treatment after forming is omitted, an area where the steel sheet base is exposed will appear at the cut end of the processed product. Depending on the environment in which the processed product is placed, red rust may occur in areas where the base steel plate is exposed. Red rust deteriorates the appearance of processed products. Furthermore, as the area where red rust occurs spreads over time, there is a concern that the strength of processed products may decrease due to red rust. Particularly in the case of home appliances, there are concerns about electrical short circuits due to lack of rust.

Further, a flange portion of a drawn product such as a motor case is sometimes provided with screw holes for fixing the processed product to other equipment. If the flatness around the screw holes is poor, there is a concern that the fastening force will decrease. In order to ensure flatness around the screw holes, when cutting the flange portion, the size of the flange portion is set large considering the size of the sag at the cut end. Increasing the dimensions of the flange portion causes an increase in the weight of the material.

As a method for improving the rust prevention ability of the cut end of a processed product, for example, in Patent Document 1, in a Zn-based plated steel plate with a thickness of 2 mm or less, a thickness of 0.0 mm of the thickness of the Zn-based plated steel plate is applied to the shoulder of the punch or die. By performing the punching process using a mold with a radius of curvature of 1 to 0.5 times, the sheared surface ratio of the punched end face after punching can be increased to 90% or more, and the zinc coverage of the sheared surface can be increased. A method to increase the ratio to 50% or more has been proposed.

Furthermore, in Patent Document 2, the punching clearance is set at 1 to 20% of the thickness of the Zn-based plated steel sheet, regardless of the thickness of the Zn-based plated steel plate, and the punch or die shoulder has a diameter of 0.12% of the thickness of the Zn-based plated steel sheet. A Zn-based plated steel plate is cut using a mold with a radius of curvature that is more than double the radius of curvature. A method to obtain this is proposed.

Furthermore, Patent Document 3 discloses a method of obtaining a product with corrosion resistance on the end face by half-blanking a plated steel plate by 60 to 95% of the plate thickness with a negative clearance and shearing it by flat pressing from the opposite side of the half-blank. is proposed.

Further, Patent Document 4 describes a first step of half punching a metal plate by adding a shaving allowance to the final processed surface of the punched part of the metal plate using a first punch and a first die; A second step of shaving, mainly shearing, is performed on the half-blanked part using a second punch and a second die, and the final machined surface of the punched part has a surface area of 70% or more. A method of pressing a metal plate material is disclosed, which ensures a sheared surface.

Furthermore, in Patent Document 5, after performing the first step with a negative clearance, the second step is performed with a positive clearance using a punch and die whose cutting edge is not rounded (R). The method is described.

Patent No. 5272518 Patent No. 6073025 Japanese Patent Application Publication No. 2002-321021 Japanese Patent Application Publication No. 2004-174542 Japanese Patent Application Publication No. 11-254055

However, the method described in Patent Document 1 is intended for steel plates with a thickness of 2 mm or less, and when a steel plate with a thickness of more than 2 mm is used as a raw material, the zinc coverage on the sheared surface is insufficient, causing red rust to occur. It can be difficult to contain. Furthermore, it is difficult to apply this method to drawn products such as motor cases where the flange ends are thickened.

In the method described in Patent Document 2, a processed product is obtained in which the sag Z at the cut end is 0.10 or more than the plate thickness, and the sag X is 0.45 times or more the plate thickness, so there is no large sag. Become. For this reason, the effective ground contact area around the screw hole decreases, resulting in a decrease in the fastening force of the fixing screw. On the other hand, increasing the dimensions of the flange portion in order to ensure flatness around the screw holes causes an increase in the weight of the material. Therefore, such a method may not be applicable to a drawn product such as a motor case in which the flange portion is fixed.

In the method described in Patent Document 3, a plated steel plate is half-blanked with a minus clearance, and sheared by flat pressing from the opposite side of the half-blank. For this reason, a fractured surface may occur at the intermediate position in the thickness direction of the cut end of the plated steel sheet, and when flat pressing, whisker-like burrs may be generated and the shape quality may deteriorate.

The method described in Patent Document 4 is a technique related to shaving processing, and the final processed surface of the metal plate material is improved by forming a large sheared surface. Even if a metal plate material having a plating layer on the surface is shaved by the method described in Patent Document 4, almost no surface plating layer remains on the final processed surface, so the corrosion resistance of the final processed surface is low.

In the method described in Patent Document 5, the cutting edges of the punch and die used in the second step are not rounded (R), so even if a plated steel plate is used as the material, a plating layer remains on the cut end surface. The effect cannot be expected.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to improve corrosion resistance and shape quality even when a plated steel plate with a thickness of more than 2.0 mm is used as a material. An object of the present invention is to provide a good processed product and a method for manufacturing the processed product.

In order to solve the above problems, according to one aspect of the present invention, a processed product is made of a plated steel sheet having a plating layer on the surface and has a cut end along the thickness direction of the processed product, The end portion has a sag, a sheared surface, and a fractured surface in this order in the thickness direction of the cut end, or a sag and a sheared surface in this order, and the sheared surface is covered with a plating layer on the surface. The ratio L/t1 of the residual length L of the component to the thickness t1 of the cut end of the workpiece is 0.70 or more, and the length Z of the sag in the thickness direction of the cut end is the thickness of the cut end of the workpiece. A processed product is provided that is more than 0 times and less than 0.10 times the plate thickness t1 at the end. The length Z of the sag in the thickness direction of the cut end may be more than 0 times and less than 0.06 times the thickness t1 of the cut end of the processed product.

The length W1 of the fracture surface in the thickness direction of the cut end may be more than 0 mm and less than 1.0 mm.

The length W1 of the fracture surface in the thickness direction of the cut end may be 0.5 mm or less.

The length X of the sag in the plane direction perpendicular to the plate thickness direction of the cut end may be more than 0 times and less than 0.30 times the plate thickness t1 of the cut end of the processed product.

The length of the burr at the cut end may be less than 0.2 mm.

The cut end has a sag, a sheared surface, a fracture surface, and a coining surface in this order in the thickness direction of the cut end, or a sag, a sheared surface, and a coining surface in this order, and the thickness of the cut end The length W2 of the fracture surface between the shear surface and the coining surface in the direction may be greater than 0 mm and less than or equal to 0.5 mm.

Moreover, in order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a method for manufacturing a processed product that uses a plated steel sheet having a plating layer on the surface as a raw material and has a cut end. Then, using a first die and a first punch in which the clearance between the first die and the first punch is set to a negative clearance, the cut portion of the first element body formed from the material is cut in half in the thickness direction. In the half-cutting process, the half-cut first element body is finished cut in the same direction as the half-cutting process using a second die and a second punch to produce a processed product having a cut end along the plate thickness direction. If the cut end is to be formed on the outer circumferential side of the workpiece, the inner diameter _D32 of the second die is greater than or equal to the inner diameter _D31 of the first die, and the cut end is cut on the inner side of the workpiece. When an end portion is formed, the outer diameter _d32 of the second die is equal to or less than the outer diameter _d31 of the first die, the thickness of the cut portion of the first element is t1, and the thickness of the cut portion after the half-cutting step is t1. Assuming that the remaining plate thickness is t2, the clearance C _31-41 between the first die and the first punch in the half-cutting process satisfies the following formula (a1), and the radius of curvature R1 of the cutting edge of the first die is calculated by the following formula ( a2) is satisfied, the pushing amount D of the first die or the first punch with respect to the cut portion of the first element satisfies the following formula (a3), and the distance C between the first die and the first punch at the bottom dead center is _PD satisfies the following formula (a4), and in the finishing cutting process, the clearance C between the second die and the second punch satisfies the following _formula (a5), and the radius of curvature of the cutting edge of the second die A processed product manufacturing method is provided in which R2 satisfies the following formula (a6).
-0.25×t1≦C _31-41 ≦-0.01...(a1)
0.10×t1≦R1≦0.50×t1 (a2)
D≧0.70×t1...(a3)
C _PD ≧0.20 ... (a4)
0.01≦C _32-42 ≦0.2×t2...(a5)
0.25≦R2≦1.50×t2...(a6)
Here, the units of C _31-41 , C _PD , C _32-42 and R2 are mm.

Furthermore, in order to solve the above problems, according to another aspect of the present invention, there is provided a method for manufacturing a processed product that uses a plated steel sheet having a plating layer on the surface as a raw material and has a cut end. Then, using a first die and a first punch in which the clearance between the first die and the first punch is set to a negative clearance, the cut portion of the first element body formed from the material is cut in half in the thickness direction. A half-cutting step, and a second die and a second punch are used to finish cut the half-cut first element from the same direction as the half-cutting, so that the cut surface has a cut end along the plate thickness direction. and a finishing cutting step to obtain a processed product, and when the cut end is formed on the outer circumferential side of the processed product, the inner diameter D ₃₂ of the second die is greater than or equal to the inner diameter D ₃₁ of the first die, and the inside of the processed product is When a cut end is formed on the side, the outer diameter _d32 of the second die is less than the outer diameter _d31 of the first die, the thickness of the cut portion of the first element is t1, and the thickness after the half-cutting process is t1. Assuming that the remaining plate thickness of the cut portion is t2, the clearance _C31-41 between the first die and the first punch in the half-cutting process satisfies the following formula (b1), and the radius of curvature R11 of the cutting edge of the first die is: The following formula (b2-1) is satisfied, and the radius of curvature R12 of the cutting edge of the first punch satisfies the following formula (b2-2), and the pushing amount D of the first die or the first punch with respect to the cut portion of the first element body is satisfies the following formula (b3), the distance C _PD between the first die and the first punch at the bottom dead center satisfies the following formula (b4), and in the finishing cutting process, the distance between the second die and the second punch A method for manufacturing a processed product is provided in which the clearance _C32-42 with the punch satisfies the following formula (b5), and the radius of curvature R2 of the cutting edge of the second die satisfies the following formula (b6).
-0.35×t1≦C _31-41 ≦-0.10×t1...(b1)
0.10×t1≦R11≦0.65×t1 (b2-1)
0.10×t1≦R12≦0.65×t1 (b2-2)
D≧0.70×t1...(b3)
C _PD ≧0.20...(b4)
0.01≦C _32-42 ≦0.2×t2...(b5)
0.25≦R2≦1.50×t2...(b6)
Here, the units of C _31-41 , C _PD , C _32-42 and R2 are mm.

The above-mentioned method for manufacturing a processed product includes processing in which the processed product obtained in the finishing cutting step is used as a second element body, the corner of the cut end of the second element is pressed against a pad, and a coining surface is formed on the corner. The method may further include a coining step of obtaining a product.

When a cut end is formed on the outer circumferential side of the processed product, the absolute value of the difference between the inner diameter D ₃₁ of the first die and the inner diameter D ₃₂ of the second die |D ₃₂ −D ₃₁ | should be 1.00 mm or less. If the cut end is formed inside the workpiece, the absolute value of the difference between the outer diameter d ₃₁ of the first die and the outer diameter d ₃₂ of the second die is |d ₃₂ −d ₃₁ | It may be 1.00 mm or less.

Further, the method for manufacturing a processed product may further include, before the half-cutting step, a preparation step of forming a first element body having a hollow side wall and a flange portion from a flat plated steel plate.

As explained above, according to the present invention, even when a plated steel plate with a thickness of more than 2.0 mm is used as a raw material, a processed product with good corrosion resistance and shape quality can be obtained. .

FIG. 1 is a perspective view showing an example of a processed product manufactured by the processed product manufacturing method according to the first embodiment of the present invention. The cut end portion 13 in region A of the workpiece 1 in FIG. 1 is shown, the left side being a cross-sectional view on the ZX plane including the central axis of the workpiece, and the right side being a side view from the X direction. FIG. 2 is a detailed view of the cross-sectional view on the left side of FIG. 2; 4 is a graph showing the relationship between sag X and sag Z in FIG. 3. FIG. It is an explanatory view showing a processed product manufacturing method concerning the same embodiment. It is an explanatory view showing a half-cutting process when the cutting edge of the die used in the half-cutting process is made into an R shape. FIG. 7 is an explanatory diagram showing a finishing cutting step performed subsequent to the half cutting step shown in FIG. 6; It is an explanatory view showing a half-cutting process in the case where the cutting edges of the die and punch used in the half-cutting process are rounded. FIG. 9 is an explanatory diagram showing a finishing cutting step performed subsequent to the half cutting step shown in FIG. 8; FIG. 6 is an explanatory diagram showing the formation positions of screw holes depending on the size of sagging X in the planar direction. FIG. 7 is an explanatory diagram showing a method for manufacturing a processed product according to a second embodiment of the present invention. It is an explanatory view showing a coining process. The cut end of the processed product after the coining process is shown, the left side is a cross-sectional view on the ZX plane including the central axis of the processed product, and the right side is a side view from the X direction. It is a photograph showing an example of a cut end of a processed product after a coining process. It is an explanatory view showing the volume of a corner crushed by a pad in a coining process. It is a perspective view showing an example of a processed product. It is a perspective view which shows another example of a processed product. It is a perspective view which shows another example of a processed product. It is a perspective view which shows another example of a processed product. FIG. 2 is a schematic diagram showing an example of a cutting die for processing a flat washer. FIG. 21 is a schematic diagram showing a state in which a material is punched out using the cutting die shown in FIG. 20; It is a perspective view which shows another example of a processed product.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals and redundant explanation will be omitted.

[1. First embodiment]
[1-1. Processed goods]
First, based on FIG. 1, a processed product 1 manufactured by a processed product manufacturing method according to a first embodiment of the present invention will be described. FIG. 1 is a perspective view showing an example of a processed product 1 manufactured by the processed product manufacturing method according to the first embodiment of the present invention. A processed product 1 shown in FIG. 1 is a motor case made of a plated steel plate having a plated layer on its surface. The motor case shown in FIG. 1 can be formed by performing a forming process such as drawing on a flat plated steel plate.

The processed product 1 according to this embodiment has a body portion 10, a protrusion 11, and a flange portion 12, as shown in FIG.

The body 10 has a hollow cylindrical side wall 101 and a top wall 103 formed to cover one end of the side wall 101. The top wall 103 may be called a bottom wall or the like depending on the direction in which the processed product 1 is used. Although the body 10 of the processed product 1 shown in FIG. 1 has a perfect circular cross-sectional shape on the XY plane, the present invention is not limited to this example. The cross-sectional shape of the body 10 along the XY plane may be other shapes such as an ellipse or a polygon.

The protruding portion 11 is a protruding body that protrudes outward from the top wall 103 in the central axis direction (Z direction) of the body portion 10 . Note that the protrusion 11 does not necessarily need to be formed, and the top wall 103 may have a flat plate shape.

The flange portion 12 is a plate portion that extends from the end of the body portion 10 (that is, the other end of the side wall 101) to the outside of the body portion 10 in the radial direction. The shape of the flange portion 12 is arbitrary. The flange portion 12 according to this embodiment extends in the radial direction of the body portion 10 over the entire circumferential area of the body portion 10 . The flange portion 12 is provided with a plurality of screw holes 121 spaced apart from each other in the circumferential direction of the body portion 10 . A screw 123 is inserted into the screw hole 121. The processed product 1 can be fixed to an object to which it is attached, such as a vehicle body, by using screws 123, for example.

The flange portion 12 according to the present embodiment is produced by cutting a flange portion body (flange portion body 20 in FIG. 5) having an outer diameter larger than the outer diameter of the flange portion 12 that is finally formed in the processed product 1. It is formed by That is, the processed product 1 according to this embodiment has a cut end portion 13 on the outer periphery of the flange portion 12.

The cutting process includes processes such as cutting, punching, and drilling. Cutting is a process of cutting an object to be cut along a predetermined straight line or curve. Punching is a process in which a product is punched out from an object to be cut. Drilling is a process in which a non-product part is punched out from a cutting target to obtain a product with an opening. The flange portion 12 shown in FIG. 1 can be obtained by punching out a flange portion element body.

As the plated steel plate, it is preferable to use a plated steel plate having various plating layers. Although various steel plates can be used as the plated steel plate, it is preferable to use a Zn-based plated steel plate. Zn-based plating includes Zn plating, Zn-Al-based alloy plating, Zn-Al-Mg-based alloy plating, and Zn-Al-Mg-Si based alloy plating. As the plated steel plate, it is particularly preferable to use a steel plate plated with a Zn-Al-Mg alloy. Here, the alloy plating preferably contains 80% by mass or more of Zn, and more preferably 90% by mass or more of Zn, based on the total number of moles of the plating.

The base steel plate of the plated steel plate is arbitrary, and may be, for example, ultra-low carbon steel.

The lower limit of the coating weight on the plated steel sheet is preferably 30 g/m ² , more preferably 45 g/m ² . Further, the upper limit of the coating weight on the plated steel sheet is preferably 450 g/m ² , more preferably 190 g/m ² . In particular, by setting the coating weight to 45 g/m ² or more, the plated metal can easily wrap around the sheared surface of the cut end 13 (the sheared surface 13c in FIG. 2), so that the corrosion resistance after cutting can be improved.

The plate thickness of the plated steel plate (thickness of the base steel plate + thickness of the plating layer) is arbitrary, and may be 2.0 mm or less or more than 2.0 mm. The thickness of the plated steel plate may be, for example, 0.8 mm or more and 6.0 mm or less, more preferably 2.0 mm or more and 4.5 mm or less.

[1-2. Cut end of processed product]
Next, the cut end portion 13 of the processed product 1 according to this embodiment will be explained based on FIGS. 2 to 4. FIG. 2 shows the cut end 13 in area A of the workpiece 1 in FIG. 1, with the left side being a cross-sectional view on the ZX plane including the central axis of the workpiece 1, and the right side being a side view from the X direction. FIG. 3 is a detailed view of the cross-sectional view on the left side of FIG. FIG. 4 is a graph showing the relationship between sag X and sag Z in FIG. In addition, in FIGS. 2 and 3, the plate thickness direction T of the flange portion 12 is assumed to be the same direction as the Z direction, which is the central axis direction of the processed product 1 shown in FIG. Moreover, in FIG. 2, the description of the plating layer 13f is omitted.

For example, as shown in FIGS. 2 and 3, the cut end portion 13 of the flange portion 12 of the workpiece 1 includes a sag 13b, a sheared surface 13c, and a fractured surface 13d in order from the upper surface 13a in the thickness direction T of the flange portion 12. and a burr 13e. Note that it is preferable that the workpiece 1 does not have the burr 13e, and the workpiece 1 according to this embodiment may be a workpiece 1 that does not have the burr 13e.

The upper surface 13a is a surface into which a cutting die is pressed during cutting of the flange element body (a surface to be pressed).

The sag 13b is a portion where the surface of the flange element (plated steel plate) is deformed due to tensile force acting on the surface of the flange element (plated steel plate) when the cutting die is pushed into the flange element. . In this specification, the dimension of the sag 13b in the thickness direction T of the flange portion 12 is referred to as a "sag Z", and the dimension of the sag 13b in a plane direction perpendicular to the thickness direction T is referred to as a "sag X".

The sheared surface 13c is a surface where the flange element body is sheared by the cutting edge of the cutting die. The sheared surface 13c is adjacent to the sag 13b in the thickness direction T of the flange portion 12.

The fracture surface 13d is a surface where cracks generated in the flange element body from the cutting edge of the cutting die meet and are fractured. The fracture surface 13d is adjacent to the shear surface 13c in the thickness direction T of the flange portion 12.

The burr 13e is a portion where the flange element body is stretched or torn off when the fracture surface 13d is formed. The burr 13e is adjacent to the fracture surface 13d in the thickness direction T of the flange portion 12.

As will be described later, by cutting the flange element body 20 using the processed product manufacturing method according to the present embodiment, the sag 13b, the fracture surface 13d, and the burr 13e can be kept small.

As shown in FIG. 3, in the method for manufacturing a processed product according to this embodiment, the cut end 13 is formed so that the plating layer 13f wraps around from the upper surface 13a of the cut end 13 to the sheared surface 13c. When the cutting edge of the cutting die bites into the flange element, the plating layer 13f is stretched by the cutting die and wraps around the sheared surface 13c. As the plating layer 13f wraps around, at least a portion of the sheared surface 13c is covered with the plating layer 13f. The occurrence of red rust can be suppressed in the portion of the sheared surface 13c covered with the plating layer 13f. Furthermore, when the plating layer 13f is a Zn-based plating layer, the sacrificial anticorrosion effect of the Zn-based plating layer can also suppress the occurrence of red rust in the vicinity of the portion covered by the plating layer 13f.

At this time, in the workpiece 1, the length L of the plating layer 13f covering at least a part of the sag 13b and the sheared surface 13c from the upper surface 13a of the cut end 13 is the thickness of the cut end 13 of the workpiece 1. This is 0.7 times or more of t1. In other words, the ratio L/t1 between the remaining length L of the plating component where the sheared surface 13c is covered by the plating layer 13f and the plate thickness t1 of the cut end 13 of the processed product 1 is 0.70 or more. The length L of the plating layer 13f can also be said to be the distance between the upper surface 13a of the cut end portion 13 in the thickness direction T of the flange portion 12 and the lower end of the plating layer 13f. Further, the thickness t1 of the cut end portion 13 of the workpiece 1 is equal to the thickness of the flange portion 12 of the workpiece 1, as shown in FIG. Therefore, below, the plate thickness of the flange portion 12 may be expressed as "plate thickness t1."

The fracture surface 13d is generated as a result of the aggregation of cracks generated in the flange element body, and is a new rough surface. At the fracture surface 13d, the metal component of the steel base is exposed. The plating layer 13f covering the sheared surface 13c is difficult to wrap around to the fractured surface 13d. Therefore, red rust is more likely to occur on the fractured surface 13d before the other surfaces of the cut end 13.

The present inventors conducted experiments in which the plate thickness t1 of the flange portion 12 on which the cut end portion 13 is formed, cutting conditions, surface treatment conditions, etc. were varied in various ranges, and investigated the occurrence of red rust. . As a result, when cutting the plated steel sheet, the plating layer 13f is wrapped around from the upper surface 13a to the sheared surface 13c, and the ratio L/t1 is set to 0.70 or more, and the sagging 13b in the plate thickness direction T of the flange portion 12 is made. The idea is to obtain a processed product 1 whose length (sagging Z) is more than 0 times and less than 0.10 times the thickness of the flange portion 12 (that is, the thickness t1 of the cut end 13 of the processed product 1). did. This cutting process eliminates red rust on the cut end 13 over time after the cutting process, without making the blank dimension excessively large in order to secure a flat area around the screw 123 necessary for fixing the workpiece 1. It was found that the occurrence of can be suppressed.

Here, the plate thickness of the flange part 12 is equal to the plate thickness t1 of the cut end part 13 of the processed product 1, and the plate thickness of the outermost part of the flange part 12 (however, the plate thickness of the part where the sag 13b does not occur) ). The length W1 of the fracture surface 13d in the thickness direction T of the flange portion 12 (hereinafter also referred to as "fracture surface length") is preferably greater than 0 mm and less than 1.0 mm. If the fracture surface length W1 is 1.0 mm or less, even if red rust occurs on the fracture surface 13d, it will not be noticeable, so it can be determined that it does not pose a practical problem. The fracture surface length W1 of the processed product 1 is preferably smaller, and may be 0.8 mm or less or 0.6 mm or less. It is more preferable that the length W1 of the fractured surface of the processed product 1 is 0.5 mm or less, 0.3 mm or less, or 0.2 mm or less. Further, the ratio W1/t1 of the fracture surface length W1 to the plate thickness t1 of the cut end portion 13 of the processed product 1 is set to less than 0.15, less than 0.10, less than 0.08, less than 0.06, or 0. It may be less than 04. Note that the fracture surface length W1 of the processed product 1 may be 0 mm. In other words, the cut end 13 of the processed product 1 does not need to have the fracture surface 13d. In this case, the cut end portion 13 has a sag 13b and a sheared surface 13c (further burr 13e if a burr 13e is generated) in order from the upper surface 13a in the thickness direction T of the flange portion 12.

Note that in order to ensure a flat area around the screw 123, it is desirable to minimize the sagging X. The sag Z and the sag X have a correlation with each other. Therefore, to summarize the sag Z that is easy to measure, it is preferable that the sag Z be less than 0.10 times the thickness of the flange portion 12, that is, the thickness t1 of the cut end portion 13 of the processed product 1. Note that the plate thickness t1 of the flange portion 12 is also equal to the plate thickness of the flange portion element body 20. It is preferable that the sag Z be smaller, and it may be less than 0.08 times, less than 0.06 times, or less than 0.04 times the thickness of the flange portion 12, that is, the thickness t1 of the cut end portion 13 of the processed product 1.

FIG. 4 shows an example of the relationship between sag Z and sag X at the cut end of a product manufactured by punching in one process. In Fig. 4, a radius of curvature of 0.01 to 0.30 is given to the cutting edge of the cutting die that is pushed into the flange element body, and the clearance of the cutting die is set to 0.0 of the plate thickness. It shows the relationship between the sag Z and the sag X at the cut end of the product when punching is performed at a setting of .01 to 0.20 times. As shown in FIG. 4, when punching is performed in one process, the sagging X appearing in the plane direction is approximately 3 to 4 times larger than the sagging Z in the thickness direction. That is, if the punching process is performed in one process, the sagging X in the plane direction will become large, and in order to secure a flat part around the screw 123 necessary for fixing the workpiece 1 to the attachment target, The trim size must be increased by an amount corresponding to the sagging X. From this, it is preferable that the sagging X be more than 0 times and less than 0.30 times the thickness of the flange portion 12 of the workpiece 1, that is, the thickness t1 of the cut end portion 13 of the workpiece 1. It is preferable that the sag It may be less than 0.1 times or less than 0.10 times.

Furthermore, the length of the burr 13e produced on the lower side of the fracture surface 13d of the cut end 13 of the workpiece 1 may be less than 0.2 mm. The burr 13e may cause dents, electrical short circuits, and the like. By setting the length of the burr 13e to less than 0.2 mm to prevent the burr from remaining on the workpiece 1 as much as possible, occurrence of dents, electrical short circuits, etc. can be suppressed. More preferably, the length of the burr 13e is less than 0.1 mm. It is most preferable that the length of the burr 13e is 0 mm, that is, there is no burr 13e on the workpiece 1.

Therefore, in the method for manufacturing a processed product according to the present embodiment, the plated steel plate is not cut in one process, but in two processes: a half-cutting process and a final cutting process. This allows more plating layer 13f to wrap around the sheared surface 13c while suppressing the sag 13b of the cut end 13 from increasing. The method for manufacturing a processed product according to this embodiment will be described below.

[1-3. Processed product manufacturing method]
First, the method for manufacturing a processed product according to this embodiment will be described based on FIG. 5. FIG. 5 is an explanatory diagram showing the method for manufacturing a processed product according to this embodiment. As shown in FIG. 5, the method for manufacturing a processed product according to this embodiment includes a preparation process, a half-cutting process, and a final cutting process.

The preparation process is a process of preparing the first element body 2. The first element body 2 can be obtained by subjecting a flat plated steel plate to a forming process such as drawing. That is, like the processed product 1, the first element body 2 is made of a plated steel plate. The first element 2 includes a flange element 20 having a larger outer diameter than the flange 12 shown in FIG. The flange element body 20 may have a circular or non-circular outer shape in plan view. The first element body 2 may have the same shape as the processed product 1 except for the flange element body 20 . Note that the preparation process is not an essential part of implementing the present invention. If an element body processed by a third party by some method can be obtained, the preparation process can be omitted.

The half-cutting process is a process of cutting the first element body 2 in half. In the half-cutting step, the flange element body 20 is cut in half. Half-cutting is a process in which the flange element body 20 is cut halfway in the thickness direction of the flange element body 20. When the flange element body 20 of the first element body 2 is cut in half, the removed portion 20a, which will ultimately be outside the product, is cut halfway from the flange element body 20.

The finishing cutting process is a process of finishing cutting the first element body 2. In the finishing cutting process, the removed portion 20a of the flange element body 20 is cut and separated from the flange element body 20. The flange portion 12 is formed by cutting the removed portion 20a. That is, in the processed product manufacturing method according to the present embodiment, the processed product 1 is obtained from the first element body 2 prepared in the preparation process through a half-cutting process and a final cutting process. The screw holes 121 of the workpiece 1 shown in FIG. 1 may be formed in the flange part element body 20 at the stage of the first element body 2, or may be formed in the flange part 12 after the final cutting process.

In the half-cutting step and the final cutting step of the method for manufacturing a processed product according to this embodiment, the flange element body 20 is processed using a die and a punch. Hereinafter, regarding the details of the half-cutting process and the final cutting process, two forms will be described according to the shapes of the cutting edges of the die and punch used in the half-cutting process. The cutting edges of dies and punches are sometimes referred to as "shoulders."

In the following description, regarding the molds used to obtain the processed product 1, for convenience, the mold on the pushing side will be referred to as a die, and the mold on the pushed side will be referred to as a punch. The mold on the pushing side may be located above or below the base body. Even when moving in the horizontal direction, the mold on the pushing side is called a die, and the mold on the pushed side is called a punch. For example, the processed product 1 shown in FIG. 2 is cut using the upper mold as the push-in mold. When the lower mold is used as a push-in mold, that is, when the lower mold is used as a die, the cut end 13 of the workpiece 1 has a sag 13b at the top of the cut end 13, contrary to FIG. It is located below and has a sheared surface 13c, a fractured surface 13d, and a burr 13e in this order above it. Therefore, the burr 13e will be located at the top. In other words, of the two surfaces of the flange element body 20 facing each other in the plate thickness direction, the die that presses the surface on the side where the sag 13b of the workpiece 1 is located after processing is called a die, and the die on the side where the burr 13e is located is called a die. The die that presses the surface is called a punch.

If it is unclear whether the upper or lower (or left or right) mold will serve as the die or the punch, after actually cutting, observe the cut end 13 and check the surface on the side where the sag 13b is located. The mold that presses the burr 13e may be called a die, and the mold that presses the surface on which the burr 13e is located may be called a punch.

As shown in FIG. 2, when the cutting edge 13 is formed on the outer circumferential side of the workpiece 1, the die is located on the outer circumferential side of the punch. During processing, the inner surface of the die faces the cutting edge 13 and the outer surface of the punch is flush with the cutting edge 13. On the other hand, when the cutting edge 13 is formed on the inner circumferential side of the workpiece 1, as in the case of cutting the inner circumferential surface of a flat washer 900 shown in FIG. located on the side. During processing, the outer surface of the die faces the cutting edge 13, and the inner surface of the punch is flush with the cutting edge 13. Furthermore, as shown in FIGS. 20 and 21, which will be described later, when cutting the outer circumferential side and the inner circumferential side of the workpiece 1 at the same time, in this embodiment, the mold 61 and the mold 63 on the pushing side are both called a die, The mold 65 on the side into which it is pushed is called a punch.

(a. When the cutting edge of the die used in the half-cutting process is R-shaped)
First, based on FIGS. 6 and 7, a half-cutting process and a final cutting process will be described in which the cutting edge of the die used in the half-cutting process is rounded. FIG. 6 is an explanatory diagram showing a half-cutting process when the cutting edge of the die used in the half-cutting process is rounded. FIG. 7 is an explanatory diagram showing a finishing cutting process performed subsequent to the half cutting process of FIG. 6.

(half cutting process)
In the half-cutting step, as shown in FIG. 6, the flange part element body 20 of the first element body 2 is cut in half using the first die 31 and the first punch 41. FIG. 6 shows a mode in which the flange portion 12 is half-cutted from the flange portion element body 20 held between the first punch 41 and the first plate holder 51, as one mode of half-cutting. The first die 31 constitutes a cutting mold that is pushed into the flange element body 20 during half cutting. In this embodiment, the first punch 41 is used as a mold for pressing the portion of the flange element body 20 that will become the flange portion 12, and the first die 31 is used as a mold for pressing the removed portion 20a.

A clearance C _31-41 between the first die 31 and the first punch 41 is a negative clearance. Here, the clearance C _31-41 represents the gap between the first die 31 and the first punch 41, and specifically, as shown in FIG. It is expressed by the distance from the side surface 41a. Based on the state where there is no clearance (that is, when C _31-41 is zero), the first die 31 and The clearance in a state where the first punch 41 is spaced apart is referred to as a positive clearance, and the clearance in a state in which the first die 31 and the first punch 41 partially overlap is referred to as a negative clearance. In this specification, regarding the clearance between the die and the punch, a plus clearance is expressed as a positive value, and a minus clearance is expressed as a negative value.

As shown in FIG. 6, the first die 31 and the first punch 41 that cut the first element body 2 in half are aligned when viewed from the pushing direction of the first die 31. They are arranged so that they overlap. If the clearance C _31-41 is set as a plus clearance, cracks generated from the cutting edges of the first die 31 and the first punch 41 will join together as in the case of one-time punching, and the removed portion 20a will be removed from the flange element body 20. may be completely severed. Moreover, the sag 13b of the cut end 13 increases. By setting the clearance C _31-41 to be a negative clearance, it is possible to avoid completely cutting the removed portion 20a from the flange element body 20 in the half-cutting process, and to reduce the sag 13b.

Further, by setting the clearance C _31-41 to be a negative clearance, a large hydrostatic stress is generated in the region sandwiched between the first die 31 and the first punch 41. Therefore, in the stress generated when the first die 31 is pushed into the flange element body 20, the stress generated between the material that will become scrap (i.e., the removed portion 20a) after cutting and the flange material that will become the flange part 12. The proportion occupied by tensile stress decreases. As a result, the material in contact with the tip of the cutting edge of the first die 31, which becomes scrap after cutting, easily flows from the tip of the cutting edge of the first die 31 toward the side surface 31a of the first die 31, and the plating layer 13f on the sheared surface 13c It is possible to increase the wraparound. Further, as the proportion of the tensile stress decreases, the compressive stress increases, and the material that would normally flow toward the scrap side is pushed back toward the flange portion 12 side. As a result, the portion that will become the sag 13b after cutting is also filled with material, and the sag 13b can also be reduced.

In the adjacent direction between the first die 31 and the first punch 41 (the X direction in FIG. 6), the shorter the length of the material that becomes scrap after cutting, the more the material is transferred from the tip of the cutting edge of the first die 31 to the first die. 31 tends to flow toward the side surface 31a side. For this reason, the first die 31 is arranged such that the side surface 31a of the first die 31 is located within a range from the end of the flange element body 20 to within twice the plate thickness of the flange element body 20 (that is, the flange part 12). 31 is preferably placed and cut in half.

The clearance C _31-41 [mm] between the first die 31 and the first punch 41 is −0.01 mm or less, and the flange element body 20 of the first element body 2 is (In other words, the thickness is set to -0.25 times or more the plate thickness t1 [mm] of the flange portion 12).

-0.25×t1≦C _31-41 ≦-0.01...(a1)

If the clearance C _31-41 is -0.01 mm or less, a negative clearance can be maintained without partially becoming a positive clearance due to the slide precision of the press machine, misalignment of the mold, etc. As a result, cracks occur during half-cutting, resulting in complete cutting, and large fracture surfaces do not occur. On the other hand, if the clearance C _31-41 is -0.25 times or more the plate thickness t1 of the flange element body 20, the forming load required for half cutting will not increase and the press capacity will not be exceeded. Therefore, the burden on the mold is small, and a decrease in the life of the mold can be suppressed. The upper limit of the clearance C _31-41 may be −0.05 times or −0.10 times the plate thickness t1 of the flange element body 20. The upper limit of the clearance C _31-41 may be −0.20 times or −0.15 times the plate thickness t1 of the flange element body 20.

The cutting edge of the first die 31 has an R shape with a radius of curvature R1, as shown in FIG. As shown in FIG. 6, since the first die 31 is pushed into the flange element body 20, the cutting edge of the first die 31 is formed into an R shape having a radius of curvature R1.

The radius of curvature R1 [mm] is at least 0.10 times the plate thickness t1 [mm] of the flange part element body 20 (i.e., the flange part 12) of the first element body 2, as shown in the following formula (a2), and 0.50 times or less.

0.1×t1≦R1≦0.5×t1 (a2)

If the radius of curvature R1 is 0.10 times or more the plate thickness t1, a large hydrostatic pressure will be generated under the negative clearance without scraping off the plating layer 13f, and the cutting edge of the first die 31 will become scrap directly under the first die 31. The material in contact with the tip can flow from the cutting edge of the first die 31 toward the side surface 31a of the first die 31. Due to this flow, stress generated when the first die 31 is pushed into the flange element body 20 causes a gap between the material that will become scrap (i.e., the removed portion 20a) after cutting and the flange material that will become the flange part 12. The proportion of generated tensile stress decreases. As a result, the sheared surface 13c can be wrapped around the plating layer 13f. On the other hand, if the radius of curvature R1 is set to 0.50 times or less than the plate thickness t1, less material will be located at the cutting edge of the first die 31 during half cutting, and a fracture surface 13d will be created during the subsequent finishing cutting. can be reduced.

Note that the cutting edge of the first punch 41 has a square shape with no roundness, as shown in FIG. At this time, the cutting edge of the first punch 41 may have a radius of curvature that is less than 0.1 times the thickness t1 of the flange element body 20 of the first element body 2. The radius of curvature of the cutting edge of the first punch 41 is set as less than 0.06 times, less than 0.04 times, or less than 0.02 times the plate thickness t1 of the flange portion element body 20 of the first element body 2, as necessary. Good too.

The pushing amount D [mm] of the first die 31 into the flange element body 20 of the first element body 2 is determined by the flange element body 20 of the first element body 2 (i.e., It is set to be 0.70 times or more the plate thickness t1 [mm] of the flange portion 12). As shown in FIG. 6, the pushing amount D is determined from the position where the first die 31 contacts the upper surface of the flange part element body 20 of the first element body 2 to the position where the pushing of the first die 31 is stopped (hereinafter, this This is the amount of movement of the first die 31 to the position (also referred to as "bottom dead center"). Further, the distance C _PD [mm] between the first die 31 and the first punch 41 at the bottom dead center is set to 0.20 mm or more, as shown in equation (a4) below.

D≧0.70×t1...(a3)
C _PD ≧0.20 ... (a4)

The remaining plate thickness t2 of the flange element body 20 (i.e., the removed portion 20a) remaining in the first element body 2 after half cutting is 0.30 times or less of the plate thickness t1 [mm] of the flange element body 20. You can also use it as Here, the remaining plate thickness t2 is the remaining plate thickness at the surface of the cut end portion 13 of the processed product 1 (this surface is the surface facing the inner circumferential surface of the first die 31). If the pushing amount D is 0.70 times or more the plate thickness t1, the fracture surface 13d will be less likely to be generated in the subsequent finishing cut. On the other hand, by ensuring the distance C _PD between the first die 31 and the first punch 41 at the bottom dead center of 0.20 mm or more, cracks may occur during half cutting, resulting in partially complete cutting. This can be avoided. Moreover, the burden on the mold is small, and a decrease in the life of the mold can be suppressed. Note that the distance C _PD is the minimum value of the distance between the first die 31 and the first punch 41 at the bottom dead center.

Note that the pushing amount D [mm] of the first die 31 into the flange part element body 20 (i.e., the flange part 12) of the first element body 2 is as shown in the above formula (a3). The thickness may be at least 0.70 times the plate thickness t1 of the flange element body 20 (that is, the flange section 12) of No. 2, but may be at most 0.95 times (0.70×t1≦D≦0. 95×t1).

The remaining plate thickness t2 is the value obtained by adding the radius of curvature R1 to the value obtained by subtracting the pushing amount D of the first die 31 into the flange part body 20 from the plate thickness t1 of the flange part body 20 (that is, the flange part 12). (t2=t1-D+R1). Therefore, the remaining plate thickness t2 is different from the distance C _PD between the first die 31 and the first punch 41 at the bottom dead center. If the pushing amount D is 0.70 times or more the plate thickness t1, the fracture surface 13d will be less likely to be generated in the subsequent finishing cut. On the other hand, if the indentation amount D is less than 0.95 times the plate thickness t1, cracks will occur during half cutting due to the sliding accuracy of the press machine, misalignment of the mold, etc., resulting in complete cutting. A large fracture surface does not occur.

(Final cutting process)
In the finish cutting process, as shown in FIG. 7, the half-cut flange element body 20 is finished cut using the second die 32 and the second punch 42. FIG. 7 shows a mode in which the flange portion 12 is finished punched from the flange portion element body 20 held between the second punch 42 and the second plate holder 52, as one mode of finish cutting. The second die 32 constitutes a cutting mold that is pushed into the flange element body 20 during finishing cutting. In this embodiment, the second punch 42 is used as a mold for pressing the portion of the flange element body 20 that will become the flange portion 12, and the second die 32 is used as a mold for pressing the removed portion 20a. The second die 32 may be the same as the first die 31. That is, the first die 31 used in the half-cutting process may be used as the second die 32 in the final cutting process.

The positional relationship between the second die 32 and the first element body 2 is preferably the same as the positional relationship between the first die 31 and the first element body 2. If these positional relationships are not the same, for example, if the diameter of the second die 32 is larger than the diameter of the first die 31, a step will occur in the cut end portion 13. Conversely, if the diameter of the second die 32 is smaller than the diameter of the first die 31, for example, the second die 32 contacts the half-cut cut end generated in the half-cutting process and wraps around the sheared surface 13c. There is a possibility that the second die 32 scrapes off the plating layer 13f.

The finishing cut according to this embodiment is performed from the same direction as the half cutting. That is, when the first die 31 is pushed into the flange element body 20 from the upper surface side of the flange element body 20 during half cutting as shown in FIG. The second die 32 is pushed into the flange element body 20 from the upper surface side. As a result, the removed portion 20a is separated from the flange element body 20. As a result, the removed portion 20a is separated from the flange element body 20.

The clearance C _32-42 [mm] between the second die 32 and the second punch 42 is a positive clearance. The clearance C _32-42 is expressed as the distance between the side surface 32a of the second die 32 and the side surface 42a of the second punch 42. Here, as in the half-cutting process, the clearance in a state where the second die 32 and the second punch 42 are separated is called a positive clearance, and the state in which the second die 32 and the second punch 42 partially overlap. The clearance at is called negative clearance.

The clearance C _32-42 between the second die 32 and the second punch 42 is 0.01 mm or more, as shown in equation (5) below, and the removed portion 20a after half cutting is the flange portion of the first element body 2. The thickness is set to 0.2 times or less of the remaining plate thickness t2 remaining in the element body 20.

0.01≦C _32-42 ≦0.2×t2 (5)

If the clearance C _32-42 is 0.01 mm or more, the second die 32 and the second punch 42 will come into contact and be damaged even if the slide accuracy of the press machine or the misalignment of the mold occurs during finishing cutting. There is no risk of it happening. On the other hand, if the clearance C _32-42 is 0.2 times or less the remaining plate thickness t2, the burr 13e is less likely to be generated.

The cutting edge of the second die 32 has an R shape with a radius of curvature R2. As shown in FIG. 7, since the second die 32 is pushed into the portion of the flange element body 20 where finishing cutting is to be performed, the cutting edge of the second die 32 has an R shape with a radius of curvature R2. Note that the cutting edge of the second punch 42 has a square shape with no roundness, as shown in FIG. At this time, the cutting edge of the second punch 42 may have a radius of curvature of less than 0.25 mm, less than 0.15 mm, less than 0.10 mm, or less than 0.05 mm. Alternatively, the radius of curvature of the cutting edge of the second punch 42 may be less than 0.1 times the plate thickness t1 of the flange element body 20 of the first element body 2, and if necessary, the radius of curvature may be less than 0.06 times, 0. It may be less than .04 times or less than 0.02 times.

The radius of curvature R2 [mm] is set to be 0.25 mm or more and 1.50 times or less the remaining plate thickness t2 of the half-cut portion, as shown in equation (6) below.

0.25≦R2≦1.50×t2 (6)

If the radius of curvature R2 is 0.25 mm or more, the second die 32 will not scrape off the plating layer 13f that has wrapped around the sheared surface 13c. On the other hand, if the radius of curvature R2 is 1.50 times or less the remaining plate thickness t2, the burr 13e is less likely to be generated.

In addition, when the cut end is formed on the outer circumference side of the workpiece 1, the inner diameter D ₃₂ of the second die 32 is set to be larger than the inner diameter D ₃₁ of the first die 31, and the cut end is formed on the inner circumference side of the workpiece 1. is formed, the outer diameter d ₃₂ of the second die 32 is equal to or less than the outer diameter d ₃₁ of the first die 31. Specifically, when a cut end is formed on the outer circumferential side of the workpiece 1, the absolute value of the difference between the inner diameter D ₃₁ of the first die 31 and the inner diameter D ₃₂ of the second die 32 |D ₃₂ - D ₃₁ | is desirably 1.00 mm or less. When a cut end is formed on the inner peripheral side of the workpiece 1, the absolute value of the difference between the outer diameter d ₃₁ of the first die 31 and the outer diameter d ₃₂ of the second die 32 | d ₃₂ - d ₃₁ | is preferably 1.00 mm or less. As a result, a diameter difference D ₃₂ -D ₃₁ or d ₃₂ -d ₃₁ of the dies 31 and 32 is generated at the cut end 13 of the workpiece 1 in order to carry out two processes: a half-cutting process and a final cutting process. It is possible to reduce the step difference and obtain a good cut cross section.

Note that if the quality of the workpiece 1 allows a step difference in the cut end 13, the absolute value of the inner diameter difference when the cut end is formed on the outer circumferential side of the workpiece 1 |D ₃₂ −D ₃₁ |, the absolute value of the outer diameter difference |d ₃₂ −d ₃₁ | when the cut end is formed on the inner peripheral side of the workpiece 1 may be more than 1.00 mm. Moreover, the upper limit of the absolute value of these diameter differences |D ₃₂ −D ₃₁ | and |d ₃₂ −d ₃₁ | is preferably smaller, and even if it is 0.75 mm, 0.50 mm, 0.35 mm, or 0.20 mm, good. The lower limit of the absolute value of the diameter difference |D ₃₂ −D ₃₁ | and |d ₃₂ −d ₃₁ | is 0 mm. It should be noted that it is preferable that the level difference generated at the cut end portion 13 of the processed product 1 is small, and may be 0.5 mm or less. The upper limit of the level difference produced at the cut end 13 of the processed product 1 may be 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm, as necessary.

(b. When the cutting edge of the die and punch used in the half-cutting process is rounded)
Next, based on FIGS. 8 and 9, a description will be given of a half-cutting process and a final cutting process when the cutting edges of the die and punch used in the half-cutting process are rounded. FIG. 8 is an explanatory diagram showing a half-cutting process in which the cutting edges of the die and punch used in the half-cutting process are rounded. FIG. 9 is an explanatory diagram showing a finishing cutting process performed subsequent to the half cutting process of FIG. 8.

(half cutting process)
In the half-cutting process, as shown in FIG. 8, the flange part element body 20 of the first element body 2 is cut in half using the first die 31 and the first punch 41. Similarly to FIG. 6, FIG. 8 shows a mode in which the flange portion 12 is half cut out from the flange portion element body 20 held between the first punch 41 and the first plate holder 51, as one mode of half cutting. The first die 31 constitutes a cutting mold that is pushed into the flange element body 20 during half cutting. In this embodiment, the first punch 41 is used as a mold for pressing the portion of the flange element body 20 that will become the flange portion 12, and the first die 31 is used as a mold for pressing the removed portion 20a.

The clearance C _31-41 between the first die 31 and the first punch 41 is a negative clearance. Therefore, as shown in FIG. 8, the first die 31 and the first punch 41 that cut the first element body 2 in half are the same as the first die 31 and the first punch 41 when viewed from the pushing direction of the first die 31. are arranged so that they partially overlap. By setting the clearance C _31-41 to be a negative clearance, it is possible to avoid completely cutting the removed portion 20a from the flange element body 20 in the half-cutting process, and to reduce the sag 13b. Note that the meanings of clearance C _31-41 , minus clearance, and plastic clearance in this embodiment b are the same as in the above-mentioned embodiment a.

Further, by setting the clearance C _31-41 to be a negative clearance, a large hydrostatic stress is generated in the region sandwiched between the first die 31 and the first punch 41. Therefore, in the stress generated when the first die 31 is pushed into the flange element body 20, the stress generated between the material that will become scrap (i.e., the removed portion 20a) after cutting and the flange material that will become the flange part 12. The proportion occupied by tensile stress decreases. As a result, the material in contact with the tip of the cutting edge of the first die 31, which becomes scrap after cutting, easily flows from the tip of the cutting edge of the first die 31 toward the side surface 31a of the first die 31, and the plating layer 13f on the sheared surface 13c It is possible to increase the wraparound. Further, as the proportion of the tensile stress decreases, the compressive stress increases, and the material that would normally flow toward the scrap side is pushed back toward the flange portion 12 side. As a result, the portion that will become the sag 13b after cutting is also filled with material, and the sag 13b can also be reduced.

In the adjacent direction between the first die 31 and the first punch 41 (the X direction in FIG. 8), the shorter the length of the material that becomes scrap after cutting, the more the material is transferred from the tip of the cutting edge of the first die 31 to the first die. 31 tends to flow toward the side surface 31a side. For this reason, the first die 31 is arranged such that the side surface 31a of the first die 31 is located within a range from the end of the flange element body 20 to within twice the plate thickness of the flange element body 20 (that is, the flange part 12). 31 and cut it in half.

The clearance C _31-41 [mm] between the first die 31 and the first punch 41 is the clearance C 31-41 [mm] of the flange element body 20 of the first element body 2 (that is, the flange part 12) It is set to -0.10 times or less and -0.35 times or more of the plate thickness t1 [mm].

-0.35×t1≦C _31-41 ≦-0.10×t1...(b1)

If the clearance C _31-41 is less than -0.10 times the plate thickness t1 of the flange element body 20, a large hydrostatic stress will occur in the area sandwiched between the first die 31 and the first punch 41, and tensile stress will occur. The stress rate decreases. As a result, cracks will not occur during half-cutting, resulting in complete cutting, and a large fracture surface will not occur, and the removed portion 20a can be completely cut from the flange element body 20 in the half-cutting process. can be avoided. On the other hand, if the clearance C _31-41 is -0.35 times or more the plate thickness t1 of the flange element body 20, the forming load required for half cutting will not increase and the press capacity will not be exceeded. Therefore, the burden on the mold is small, and a decrease in the life of the mold can be suppressed. It is more preferable that the clearance C _31-41 is -0.15 times or less or -0.20 times or less the plate thickness t1 of the flange element body 20. The clearance C _31-41 may be -0.30 times or more or -0.25 times or more the plate thickness t1 of the flange element body 20.

In this embodiment, as shown in FIG. 8, the cutting edges of the first die 31 and the first punch 41 are rounded. The radius of curvature R11 [mm] of the cutting edge of the first die 31 and the radius of curvature R12 [mm] of the cutting edge of the first punch 41 are as shown in the following formulas (b2-1) and (b2-2), The plate thickness t1 [mm] of the flange part element body 20 (namely, the flange part 12) of the first element body 2 is set to be 0.10 times or more and 0.65 times or less. Note that the radius of curvature R11 of the cutting edge of the first die 31 and the radius of curvature R12 of the cutting edge of the first punch 41 may be the same or different.

0.10×t1≦R11≦0.65×t1 (b2-1)
0.10×t1≦R12≦0.65×t1 (b2-2)

If the radii of curvature R11 and R12 are 0.10 times or more the plate thickness t1, a large hydrostatic pressure will be generated under the negative clearance without scraping off the plating layer 13f, and the material that will become scrap directly under the first die 31 will be removed from the first die 31. It can be made to flow from the cutting edge of the die 31 toward the side surface 31a of the first die 31. Due to this flow, stress generated when the first die 31 is pushed into the flange element body 20 causes a gap between the material that will become scrap (i.e., the removed portion 20a) after cutting and the flange material that will become the flange part 12. The proportion of generated tensile stress decreases. As a result, the sheared surface 13c can be wrapped around the plating layer 13f. On the other hand, if the radii of curvature R11 and R12 are set to 0.65 times or less the plate thickness t1, less material will be located at the cutting edge of the first die 31 during half cutting, and the fracture surface 13d will be reduced during the subsequent finishing cut. generation can be reduced.

The pushing amount D [mm] of the first die 31 into the flange part element body 20 (i.e., the flange part 12) of the first element body 2 is calculated as shown in the following formula (b3). It is set to 0.70 times or more the plate thickness t1 [mm] of the element body 20 (that is, the flange portion 12). The pushing amount D is the distance from the position where the first die 31 contacts the upper surface of the flange part element body 20 of the first element body 2 to the position (bottom dead center) at which the first die 31 stops pushing. The amount of movement is 31. The distance C _PD [mm] between the first die 31 and the first punch 41 at the bottom dead center is set to 0.20 mm or more, as shown in equation (b4) below.

D≧0.70×t1...(b3)
C _PD ≧0.20...(b4)

The residual plate thickness t2 of the removed portion 20a remaining in the flange element body 20 of the first element body 2 after half cutting may be 0.30 times or less of the plate thickness t1 [mm] of the flange element body 20. . If the pushing amount D is 0.70 times or more the plate thickness t1, the fracture surface 13d will be less likely to be generated in the subsequent finishing cut. On the other hand, by ensuring the distance C _PD between the first die 31 and the first punch 41 at the bottom dead center of 0.20 mm or more, cracks may occur during half cutting, resulting in partially complete cutting. This can be avoided. Note that the distance C _PD is the minimum value of the distance between the first die 31 and the first punch 41 at the bottom dead center.

By making the cutting edges of the first die 31 and the first punch 41 R-shaped, half-cutting is possible compared to the case where only one of the first die 31 and the first punch 41 has an R-shaped cutting edge, as shown in FIG. The amount of cutting of the flange element body 20 in the process can be increased. That is, by making the cutting edges of the first die 31 and the first punch 41 R-shaped, compared to the case where only one of the first die 31 and the first punch 41 has a cutting edge R-shaped, as shown in FIG. After the half-cutting, the removed portion 20a can reduce the residual plate thickness t2 remaining in the flange element body 20.

When only the first die 31 has an R-shaped cutting edge as in the above-mentioned form a, if the pushing amount D of the first die 31 is equal to or greater than the plate thickness t1 of the flange portion 12, the cutting edge of the first die 31 becomes the first punch. It comes into contact with the cutting edge of No. 41. Therefore, in the above embodiment a, the pushing amount D of the first die 31 cannot be greater than the plate thickness t1 of the flange portion 12. However, if the cutting edges of the first die 31 and the first punch 41 are rounded, as shown in FIG. The amount that can be pushed becomes larger. Therefore, it is possible to increase the amount of cutting of the flange element body 20 compared to the form a, and the ratio of the sheared surface 13c in the cut end 13 can be increased. Thereby, the plating layer 13f can be made to wrap more around the sheared surface 13c, and the proportion of the cut end portion 13 covered by the plating layer 13f can be increased. In addition, since the remaining plate thickness t2 becomes smaller, the amount of cutting in the final cutting step becomes smaller, and it is possible to avoid a situation in which the plating layer does not remain in a part of the final cut portion.

(Final cutting process)
In the finishing cutting step, as shown in FIG. 9, the half-cut flange element body 20 is finished cutting using the second die 32 and the second punch 42. The finishing cutting process may be performed in the same manner as the finishing cutting process shown in FIG. 7, which is performed after half-cutting is performed with only one of the first die 31 and the first punch 41 having an R-shaped cutting edge.

FIG. 9 shows a mode in which the flange portion 12 is finished punched from the flange portion element body 20 held between the second punch 42 and the second plate holder 52, as one mode of finish cutting. The second die 32 constitutes a cutting mold that is pushed into the flange element body 20 during finishing cutting. In this embodiment, the second punch 42 is used as a mold for pressing the portion of the flange element body 20 that will become the flange portion 12, and the second die 32 is used as a mold for pressing the removed portion 20a. The second die 32 may be the same as the first die 31. That is, the first die 31 used in the half-cutting process may be used as the second die 32 in the final cutting process.

The positional relationship between the second die 32 and the first element body 2 is preferably the same as the positional relationship between the first die 31 and the first element body 2. If these positional relationships are not the same, for example, if the diameter of the second die 32 is larger than the diameter of the first die 31, a step will occur in the cut end portion 13. Conversely, if the diameter of the second die 32 is smaller than the diameter of the first die 31, for example, the second die 32 contacts the half-cut cut end generated in the half-cutting process and wraps around the sheared surface 13c. There is a possibility that the second die 32 scrapes off the plating layer 13f.

The finishing cut according to this embodiment is performed from the same direction as the half cutting. That is, when the first die 31 is pushed into the flange element body 20 from the upper surface side of the flange element body 20 during half cutting as shown in FIG. The second die 32 is pushed into the flange element body 20 from the upper surface side. As a result, the removed portion 20a is separated from the flange element body 20.

The clearance C _32-42 [mm] between the second die 32 and the second punch 42 is a positive clearance. The clearance C _32-42 between the second die 32 and the second punch 42 is 0.01 mm or more, as shown in the above formula (5), and the removed portion 20a after half cutting is the flange of the first element body 2. The thickness is set to 0.2 times or less of the remaining plate thickness t2 remaining in the component body 20. If the clearance C _32-42 is 0.01 mm or more, the second die 32 and the second punch 42 will come into contact and be damaged even if the slide accuracy of the press machine or the misalignment of the mold occurs during finishing cutting. There's nothing to do. On the other hand, if the clearance C _32-42 is 0.2 times or less the remaining plate thickness t2, the burr 13e is less likely to be generated.

The cutting edge of the second die 32 has an R shape with a radius of curvature R2. As shown in FIG. 9, since the second die 32 is pushed into the portion of the flange element body 20 where finishing cutting is to be performed, the cutting edge of the second die 32 is formed into an R shape having a radius of curvature R2. Note that the cutting edge of the second punch 42 may be a rectangular shape with no roundness, as shown in FIG. 9, or may have a radius of curvature. If the cutting edge of the second punch 42 is made into a rectangular shape without roundness, burrs generated at the tip of the fracture surface 13d can be further reduced. The radius of curvature of the cutting edge of the second punch 42 may be less than 1.00 mm, less than 0.50 mm, less than 0.20 mm, less than 0.10 mm, or less than 0.05 mm. Alternatively, the radius of curvature of the cutting edge of the second punch 42 may be less than 0.3 times the plate thickness t1 of the flange element body 20 of the first element body 2, and if necessary, the radius of curvature may be less than 0.1 times, 0. It may be less than .06 times, less than 0.04 times, or less than 0.02 times.

The radius of curvature R2 [mm] is set to be 0.25 mm or more and 1.50 times or less of the remaining plate thickness t2 of the half-cut portion, as shown in equation (6) above. If the radius of curvature R2 is 0.25 mm or more, the second die 32 will not scrape off the plating layer 13f that has wrapped around the sheared surface 13c. On the other hand, if the radius of curvature R2 is 1.50 times or less the remaining plate thickness t2, the burr 13e is less likely to be generated.

The method for manufacturing a processed product according to the first embodiment of the present invention has been described above. According to the present embodiment, the clearance between the first die 31 and the first punch 41 is a minus clearance when the first element body 2 which is formed from a plated steel plate and has the flange element body 20 that becomes the flange part 12 is to be cut. A half-cutting step of cutting the flange part element body 20 of the first element body 2 in half using the first die 31 and the first punch 41 set to , and using the second die 32 and the second punch 42, The process includes a finishing cutting step of cutting the half-cut flange part element body 20 in the same direction as the half-cutting to obtain a processed product 1 having a cut end 13 on the flange part 12.

The cut end portion 13 of the flange portion 12 of the workpiece 1 cut through these two steps has a sag 13b, a sheared surface 13c, and a fractured surface 13d in order in the thickness direction T of the cut end 13. ing. At least a portion of the sheared surface 13c is covered with a plating layer 13f on the upper surface 13a. At this time, the ratio L/t1 of the remaining length L of the plating component where the sheared surface 13c is covered by the plating layer 13f1 and the plate thickness t1 of the cut end 13 of the processed product 1 is 0.70 or more, The length of the sag 13b in the thickness direction T of the cut end 13 is more than 0 times and less than 0.10 times the thickness t1 of the cut end 13 of the processed product 1. In this way, in the processed product 1, the sagging 13b of the cut end 13 is suppressed from increasing, and more of the plating layer 13f wraps around the sheared surface 13c. Even when a plated steel plate with a thickness of more than 2.0 mm is used as the material, corrosion resistance and shape quality can be made good.

If the length of the sagging 13b (the sagging X) in the plane direction (XY plane direction) can be reduced, the amount of material used for the processed product 1 can be reduced. For example, as shown in FIG. 1, the screw hole 121 into which the screw 123 for fixing the workpiece 1 is inserted is formed in the flange part 12 avoiding the sag 13b so that the screw 123 is fixed to the flat part. be done. As shown in the upper part of FIG. 10, when the sagging X increases, the distance from the end of the flange portion 12 to the screw hole 121 becomes longer, and extra material is required. On the other hand, as shown on the lower side of FIG. 10, if the sagging X is small, the distance from the end of the flange portion 12 to the screw hole 121 becomes short, and the material used to form the flange portion 12 can be reduced. In this way, the method for manufacturing a workpiece according to the present embodiment eliminates the need to make the blank dimension extra large in order to secure a flat portion around the screw 123 necessary for fixing the workpiece 1.

Furthermore, the method for manufacturing a processed product according to the present embodiment allows more of the plating layer 13f to wrap around the sheared surface 13c, thereby suppressing red rust on the cut end 13 that occurs over time after cutting. I can do it.

Furthermore, the clearance C _32-42 between the second die 32 and the second punch 42 is 0.01 mm or more, and the remaining plate thickness of the first element body 2 (flange element body 20) at the half-cut portion It is set to 0.2 times or less of t2. Thereby, generation of burrs 13e can be suppressed while avoiding contact and damage of the cutting mold during finishing cutting.

Further, the cutting edge of the second die 32 that is pushed into the part to be finished cut of the first element body 2 has a thickness of 0.25 mm or more and 1.0 mm of the remaining plate thickness t2 of the half-cut part. A curved shape having a radius of curvature R2 of 50 times or less is provided. Thereby, the formation of burrs 13e can be suppressed while preventing the cutting die from scraping off the plating layer 13f that has wrapped around the sheared surface 13c.

[2. Second embodiment]
Next, a method for manufacturing a processed product according to a second embodiment of the present invention will be described based on FIG. 11. FIG. 11 is an explanatory diagram showing a method for manufacturing a processed product according to the second embodiment of the present invention. As shown in FIG. 11, the method for manufacturing a processed product according to this embodiment includes a preparation process, a half-cutting process, a finishing cutting process, and a coining process.

The processed product manufacturing method according to the present embodiment is a method in which a coining process is added to the processed product manufacturing method according to the first embodiment shown in FIG. As shown in FIG. 11, in this embodiment as well, a half-cutting process and a final cutting process are performed on the first element body 2 prepared in the preparation process, similarly to the first embodiment. Therefore, detailed explanations of the preparation process, half-cutting process, and final cutting process will be omitted.

In the coining process, a coining process is performed on the second element body 6 using the processed product obtained in the finish cutting process as the second element body 6. In the coining process, after the final cutting process, the corner 13g of the cut end 13 on the side of the fracture surface 13d is pressed against a pad (pad 7 in FIG. 12), and the processed product has a coining surface 13h formed at the corner. Get 1. By the coining process, the region of the fracture surface 13d, which is a new rough surface, can be narrowed, and the region where red rust occurs can be suppressed. Moreover, the coining process can crush the burr 13e, and can more reliably suppress the burr 13e from remaining in the processed product 1.

The coining process will be explained in more detail based on FIGS. 12 to 14. FIG. 12 is an explanatory diagram showing the coining process. FIG. 13 shows the cut end of the workpiece 1 after the coining process, with the left side being a sectional view on the ZX plane including the central axis of the workpiece 1, and the right side being a side view from the X direction. FIG. 14 is a photograph showing an example of the cut end of the processed product 1 after the coining process. In addition, in FIG. 13, the description of the plating layer 13f is omitted as in FIG. 2.

As shown in FIG. 12, in the coining process according to this embodiment, the cut end 13 of the second element body 6 is sandwiched between the pad 7 and the coining block 8. The pad 7 has a vertical wall surface 70, a bottom wall surface 71, and a pressing surface 72.

The vertical wall surface 70 is arranged so as to face and be substantially parallel to the sheared surface 13c of the second element body 6 when the cut end portion 13 of the second element body 6 is sandwiched between the pad 7 and the coining block 8. be done. The vertical wall surface 70 is arranged parallel to the advancing and retreating direction of the coining block 8 (the Z direction in FIG. 12).

The bottom wall surface 71 is arranged to face the coining block 8 in the thickness direction of the flange portion 12 with the second element body 6 in between. The bottom wall surface 71 extends below the vertical wall surface 70 (that is, on the opposite side from the coining block 8) in a direction perpendicular to the vertical wall surface 70.

The pressing surface 72 is a surface that connects the bottom wall surfaces 71 to each other. The pressing surface 72 is provided to form a coining surface (the coining surface 13h in FIG. 13) on the second element body 6, and is formed in a shape corresponding to the shape of the coining surface. For example, as shown in FIG. 13, when the coining surface 13h is a planar chamfered surface (hereinafter referred to as "C surface"), the pressing surface 72 is It may be an inclined plane. Further, for example, when the coining surface 13h is a curved surface (which may be either a pressing surface or a compression surface, hereinafter referred to as "R surface"), the pressing surface 72 may be a curved surface.

In the coining process, as shown in FIG. 12, with the cut end 13 of the second element body 6 facing the vertical wall surface 70 of the pad 7, the second The element body 6 is sandwiched in the thickness direction T. Then, the coining block 8 is pushed toward the bottom wall surface 71, and the second element body 6 is pushed down to a position where the bottom surface 13k of the second element body 6 contacts the bottom wall surface 71. Here, before the bottom surface 13k of the second element body 6 comes into contact with the bottom wall surface 71, the corner portion 13g is pressed against the pressing surface 72. After the corner portion 13g is pressed against the pressing surface 72, the coining block 8 is further pushed in, and the bottom surface 13k of the second element body 6 comes into contact with the bottom wall surface 71. The corner 13g is crushed by the pressing surface 72 and becomes a coining surface 13h. The cut end portion 13 of the processed product 1 after the coining process is in a state as shown in the photograph of FIG. 14, for example.

The coining surface 13h is a smooth surface onto which the surface of the pressing surface 72 is transferred, and red rust is less likely to occur compared to the rough fractured surface 13d. This is thought to be because the smooth surface roughness makes it difficult for moisture to accumulate on the coining surface 13h. Further, it is considered that the fact that the plating layer 13f on the bottom surface 13k side of the cut end portion 13 is thinly extended to the coining surface 13h is also a factor that makes it difficult for red rust to occur. By forming the coining surface 13h on the corner 13g on the side of the fracture surface 13d, the fracture surface length W2 (see FIG. 13) in the thickness direction T of the flange portion 12 after the coining process is the same as that of the flange portion before the coining process. It is shorter than the fracture surface length W1 in the plate thickness direction T at No. 12 (see FIGS. 2 and 3). That is, the coining process can narrow the region of the fracture surface 13d, which is a newly formed rough surface, and can suppress the region where red rust occurs. Moreover, the coining process can crush the burr 13e, and can more reliably suppress the burr 13e from remaining in the processed product 1.

In the coining process, the length (fracture surface length) W2 of the fracture surface 13d between the shear surface 13c and the coining surface 13h in the plate thickness direction T of the flange portion 12 of the workpiece 1 is set to be more than 0 mm and less than 0.5 mm. The pressing surface 72 is pressed against the corner 13g so that the pressing surface 72 is pressed against the corner 13g. By setting the fracture surface length W2 to be more than 0 mm and 0.5 mm or less, even if red rust occurs on the fracture surface 13d, it is not noticeable and it can be determined that it does not pose a problem in practice.

In addition, in the finishing cutting process, it is preferable to obtain the second element body 6 whose fracture surface length W1 in the plate thickness direction T is less than 1.0 mm. By obtaining the second element body 6 having a fracture surface length W1 of less than 1.0 mm, the fracture surface length W2 can be more reliably set to 0.5 mm or less in the coining process. The fracture surface length W2 of the processed product 1 is preferably smaller, and may be 0.4 mm or less or 0.3 mm or less. It is more preferable that the length W2 of the fractured surface of the processed product 1 is 0.2 mm or less or 0.1 mm or less. Further, the ratio W2/t1 of the fracture surface length W2 to the plate thickness t1 of the cut end portion 13 of the processed product 1 is set to less than 0.15, less than 0.10, less than 0.08, less than 0.06, or 0. It may be less than 04. Note that the fracture surface length W2 of the processed product 1 may be 0 mm. In other words, the cut end 13 of the processed product 1 does not need to have the fracture surface 13d. That is, as shown in FIG. 13, for example, the cut end 13 may have a sag 13b, a sheared surface 13c, a fractured surface 13d, and a coining surface 13h in this order in the thickness direction of the cut end 13. Alternatively, the cut end 13 may have a sag 13b, a sheared surface 13c, and a coining surface 13h in this order in the thickness direction of the cut end 13.

FIG. 15 is an explanatory diagram showing the volume of the corner 13g crushed by the pressing surface 72 of the pad 7 in FIG. 12. As the coining block 8 in FIG. 12 is pushed down toward the bottom wall surface 71 of the pad 7, the corner 13g comes into contact with the pressing surface 72 and is crushed. The material (base steel) of the crushed corner 13g moves along the pressing surface 72 toward the sheared surface 13c. When the cut end 13 is pushed down to the position where the bottom surface 13k of the cut end 13 contacts the bottom wall surface 71, the corner 13g of the flange portion 12 is crushed by the pressing surface 72 depending on the position and angle of the pressing surface 72. The volume V1 of changes.

In the coining process, as shown in the upper side of FIG. 15, the volume V1 of the corner 13g crushed by the pressing surface 72 is reduced to the volume V2 of the coining space surrounded by the extension surface 13j of the sheared surface 13c, the fractured surface 13d, and the pressing surface 72. The following is preferable. As shown in FIG. 12, the fracture surface 13d of the cut end 13 of the flange portion 12 is inclined with respect to the vertical wall surface 70, and there is a gap therebetween. The volume V2 of the coining space created by this gap becomes a space into which the material of the corner portion 13g crushed by the pressing surface 72 flows. If the volume V2 of the coining space is smaller than the volume V1 of the corner 13g crushed by the pressing surface 72, the material of the corner 13g crushed by the pressing surface 72 cannot be contained within the volume V2, and the It will move towards the top of 7.

Therefore, by setting the volume V1 to be less than or equal to the volume V2, it is possible to prevent the material of the corner portion 13g crushed by the pressing surface 72 from protruding beyond the extension surface 13j of the sheared surface 13c. As shown in the lower part of FIG. 15, when the volume V1 exceeds the volume V2, the material of the corner 13g crushed by the pressing surface 72 protrudes beyond the extended surface 13j of the sheared surface 13c and moves toward the top of the pad 7. Events such as movement occur. When such an event occurs, the dimensional accuracy of the cut end 13 deteriorates. Therefore, it is preferable to process the corner portion 13g so that the pressing surface 72 crushes the corner portion 13g so that the volume V1 becomes equal to or less than the volume V2.

The method for manufacturing a processed product according to the second embodiment has been described above. According to this embodiment, similarly to the first embodiment, there is no need to make the blank dimension extra large in order to secure a flat portion around the screw 123 necessary for fixing the workpiece 1. Further, since more of the plating layer 13f can be wrapped around the sheared surface 13c, it is possible to suppress red rust on the cut end 13 that occurs over time after cutting.

Furthermore, by performing the coining process after the finishing cutting process, the area of the fracture surface 13d, which is a new rough surface, can be narrowed, and the area where red rust occurs can be suppressed. Further, since the burr 13e can be crushed by the coining process, the remaining burr 13e in the processed product 1 is less than 0.2 mm, and the remaining burr 13e can be suppressed more reliably. The length of the burr 13e is preferably less than 0.1 mm, more preferably less than 0.05 mm or less than 0.01 mm. It is most preferable that the length of the burr 13e is 0 mm, that is, there is no burr 13e on the workpiece 1.

[3. Examples of processed products]
In the above embodiment, a case has been described in which the processed product 1 is a motor case as shown in FIG. It may be any article having a cut end 13.

The processed product 1 may be, for example, an annular flat washer 900 as shown in FIG. 16. Further, the processed product 1 may be flat washers 910A, 910B, and 910C having teeth 911 as shown in FIG. 17, for example. Alternatively, the workpiece 1 may be a wavy annular disc spring 920 as shown in FIG. 18, for example. The disc spring 920 shown in FIG. 18 can be manufactured by processing the flat washer 900 shown in FIG. 16 into a corrugated shape, for example. Further, the workpiece may be a disc spring 930 having teeth 931 as shown in FIG. 19, for example.

When the processed product 1 is an annular plate member of various types as shown in FIGS. 16 to 19, the outer circumference and inner circumference thereof become the cut ends 13. By applying the method for manufacturing a processed product according to the embodiment described above, at least one of the outer peripheral portion and the inner peripheral portion is plated in the thickness direction T of the processed product 1, with the sheared surface 13c covered with the plating layer 13f1. The ratio L/t1 between the residual length L of the component and the thickness t1 of the cut end 13 of the workpiece 1 is set to 0.70 or more, and the length of the sag 13b is set to the thickness of the cut end 13 of the workpiece 1. It can be less than 0.10 times t1.

For example, in order to cover the sheared surfaces of the inner circumferential surface and outer circumferential surface of the flat washer 900 shown in FIG. 16 with a plating layer, processing may be performed using a cutting mold as shown in FIGS. 20 and 21. . FIG. 20 is a schematic diagram showing an example of a cutting die for processing the flat washer 900. FIG. 21 is a schematic diagram showing a state in which the element body 9 is punched using the cutting die shown in FIG. 20.

The cutting mold shown in FIG. 20 is a mold for manufacturing an annular processed product 90 such as a flat washer 900, and includes a hollow cylindrical die (hereinafter referred to as "outer die") 61 and a cylindrical die 61. It has a hollow cylindrical die 63 (hereinafter referred to as an "inner die") and a hollow cylindrical punch 65 that supports a disc-shaped element body 9 (see FIG. 21). The outer die 61, the inner die 63, and the punch 65 are provided to face each other, and the element body 9 is cut by pushing the outer die 61 and the inner die 63 into the element body 9 supported by the punch 65. The inner diameter of the outer die 61 corresponds to the outer diameter of the workpiece 90, and the outer diameter of the inner die 63 corresponds to the inner diameter of the workpiece 90. The cutting edge on the inner peripheral surface of the outer die 61 and the cutting edge on the outer peripheral surface of the inner die 63 have an R shape with a radius of curvature. On the other hand, the edges of the inner circumferential surface and outer circumferential surface of the punch 65 do not have a rounded shape.

When the element body 9 is finished cut with such a cutting die, as shown in FIG. The inner die 63 cuts the portion 9b which is on the inner side of the circumferential surface 92. As a result, a processed product 90 (flat washer 900) as shown in FIG. 20 is formed. At this time, the sheared surface of the outer circumferential surface 91 and the inner circumferential surface 92 of the processed product 90 is the ratio L of the remaining length L of the plating component covered by the plating layer and the plate thickness t1 of the cut end of the processed product 90. /t1 is 0.70 or more, and the length of the sag in the thickness direction of the cut end can be less than 0.10 times the thickness t1 of the cut end of the processed product 90.

Furthermore, the processed product 1 may be, for example, a disc-shaped plate 940 as shown in FIG. 22.

(Example a. When only the cutting edge of the die used in the half-cutting process is rounded)
Samples of processed products were prepared by the method shown in FIGS. 5 and 11, with the shoulder portion (ie, the cutting edge) of the die used in the half-cutting step having an R shape with a predetermined radius of curvature. As a plated steel plate, Zn-6%Al-3%Mg (mass ratio) alloy with a plate thickness of 1.4 to 3.8 mm and a coating weight of 90 g/m ² (one side) or 190 g/m ² (one side) A plated steel plate was used. The half-cutting process was carried out using a round die with an inner diameter D ₃₁ of 85.00 mm and a punch whose diameter was changed depending on the clearance between the die and the punch, and the plated steel plate was held by a plate holder. The finishing cutting process was performed by using a die whose shoulder part (that is, the cutting edge) had an R shape with a predetermined radius of curvature, and a punch whose diameter D ₃₂ was changed according to the clearance C _32-42 between the die and the punch. The plated steel plate was held by a presser.

For each sample, sagging Z, sagging X, the length of the fractured surface after finishing cutting (W1), and when coining was performed, the length of the fractured surface after coining (W2) were measured. These were determined by measuring the circumference of the end face of the processed product at 30° intervals using a microscope, and averaging the measured values at 12 points in total. In addition, for each sample, regarding the wrapping of the plating layer to the cut end, the length L of the wrapping of the plating layer in the thickness direction of the plated steel sheet was measured from the cross section of the central portion of the right side of the processed product. An electron beam microanalyzer (EPMA-WDS) was used to measure the length L of the plating layer at the cut end. It was determined that a plating layer existed in a portion where the detection level of the Zn component was three times or more the background. Note that the objects to be measured are the processed product after finish cutting or the second element body and the processed product after coining processing.

In addition, at the cut end of each sample, the sag, shear surface, fracture surface, and coining surface are as shown in FIG. 14, and more specifically, they appear as follows.

Sag appears as a smooth surface created when the surface of the workpiece is stretched by compression (pressure) force applied after the die contacts the workpiece. As shown in FIG. 3, when the cut end is viewed from the side, it has a shape with curvature.

The sheared surface appears as a smooth surface at the cut end. The sheared surface is generated when the die rubs against the side surface of the die by applying compression (pressure) force and biting into the workpiece after the die contacts the workpiece. Because it rubs against the die, the sheared surface exhibits a metallic luster. On the sheared surface, fine streak-like sliding scratches can be seen in the thickness direction.

The fracture surface is a surface where cracks generated in the workpiece from the shear surface side join together and break, and appears as a dull, rough surface. When the die further bites into the workpiece after a sheared surface is generated in the workpiece, the punch's cutting edge causes cracks in the workpiece, and the die's cutting edge also causes cracks in the workpiece. Cracks originating from the punch and die meet and penetrate each other. The surface formed by cracking in this way becomes a fracture surface. Since the fractured surface is formed without contact between the punch and the die, it becomes a rough surface without gloss. The fracture surface has an inclination depending on the gap (clearance) between the punch and the die.

The coining surface appears as a smooth surface where the irregularities of the fracture surface have been crushed. The coining surface is obtained by pressing an inclined or curved coining mold against the corner of the fractured surface from the lower surface side of the edge of the fractured surface. The surface roughness of the coining die is transferred to the coining surface, so that the unevenness of the fracture surface is flattened and becomes a smooth surface.

A method for identifying sagging, sheared surfaces, fracture surfaces, and coining surfaces at the cut end is, for example, to observe and measure the shape profile of the cut end using a microscope or a contracer from the outside based on the above characteristics. There are methods etc.

From the perspective of ensuring flatness around the fixing screw, those with a sagging Z of the cut end 13 of less than 0.10 times are classified as "A (acceptable)," and those with 0.10 times or more are designated as "B (unacceptable)." It was evaluated. Regarding burrs that can cause dents and electrical short circuits, those with a size of less than 0.2 mm are rated "A (Acceptable)," and those with a size of 0.2 mm or more or whisker-like burrs have occurred. The item was rated "B (unacceptable)". In addition, it is desirable to minimize the step difference on the end surface from the viewpoint of appearance and product dimensional accuracy. Therefore, those with a step difference of 0.5 mm or less on the end face were evaluated as "A (acceptable)", and those with a step difference of more than 0.5 mm were evaluated as "B (unacceptable)".

In addition, the samples were subjected to an atmospheric exposure test outdoors, and the number of days until noticeable red rust appeared on the cut ends was observed every 15 days.

The above results are shown in Table 1. Table 1 also shows the plated steel sheets used for each sample, the conditions of the half-cutting process, the final cutting process, and whether or not the corners of the cut ends were coined. Here, the plate thickness ratio of the radius of curvature of the die (R1/t1, R2/t2) is obtained by dividing the roundness given to the shoulder of the die by the plate thickness. If the die shoulder (cutting edge) was not intentionally rounded, "<0.01" was written in this column.

As shown in Table 1, in Examples a1 to a19, the remaining length L of the plating component is 0.70 times or more with respect to the plate thickness t1 at the cut end, and the size of the sag Z appearing in the plate thickness direction is was less than 0.10 times the plate thickness t1 at the cut end of the processed product. The fracture surface length W1 of the cut end was all 1.0 mm or less, and Examples a1 to a19 exhibited good corrosion resistance for 60 days until red rust appeared. In Examples a1 to a13, the size of the sagging X appearing in the plane direction was less than 0.30 times the plate thickness t1 at the cut end of the processed product. Examples a1 to a16 in which the fracture surface length W1 of the cut end was 0.5 mm or less exhibited good corrosion resistance for 90 days or more until red rust appeared.

In Examples a1 to a14, the remaining length L of the plating component was 0.80 times or more with respect to the plate thickness t1 at the cut end of the processed product, and the fracture surface length (W1) was in the range of 0.5 mm or less. . Further, in Example a15, after finishing punching, a coining process was performed to form a coining surface with an R surface in which the length of the side to be crushed (width of the coining surface) was 0.6 mm. In Example a16, after finishing punching, a coining process was performed to form a C-plane coining surface chamfered at an angle of 45° with the length of the crushed side (width of the coining surface) being 1.0 mm. The fracture surface length (W2) after the coining process is smaller than the fracture surface length W1 of the other examples. The absolute value of the difference between the diameter D ₃₁ of the die for cutting and the diameter D ₃₂ of the die for finishing cutting |D ₃₂ −D ₃₁ | is set to 0.05 mm in Examples a1 to a17, and zero in Example A18. (The diameter D ₃₁ and the diameter D ₃₂ are the same) and in Example a19, it was 1.00 mm, but in both cases, the step difference on the end face was 0.5 mm or less.

Note that the cut ends of Examples a1 to a14, a18, and a19 have a sag, a sheared surface, and a fracture surface in order in the thickness direction, and the cut ends of Examples a15 and a16 have a sag in the thickness direction. Based on the above-mentioned characteristics, it was confirmed from the external appearance that it had a sag, a sheared surface, a fractured surface, and a coined surface in that order.

On the other hand, in Comparative Examples a1 to a5, a8, a10 to a13, and a16, the remaining length L of the plating layer component was less than 0.70 times the plate thickness t1 at the cut end of the processed product. The number of days until red rust appeared on the edges was less than 60 days, and the corrosion resistance was inferior compared to the examples. In Comparative Example a9, a large negative clearance was adopted in the half-cutting process, but the press machine stopped due to excessive load during the half-blanking process using a 750 kN mechanical press. Comparative Examples a14 and a15 both exhibited good corrosion resistance for 90 days or more until red rust appeared on the cut ends, but large burrs of 0.2 mm or more were generated on the cut ends.

Comparative Example A6 showed good corrosion resistance, with the number of days until red rust appeared on the cut end being 90 days or more, but the size of the sag Z appearing in the plate thickness direction was 0.10 times or more the plate thickness of the flange material. In addition, the size of the sagging X appearing in the plane direction is 0.30 times or more the thickness of the processed product, and the flange size must be increased accordingly when screwing. Comparative example a7 is a case in which the clearance between the die and the punch in the half-cutting process was set to zero, and the plated steel plate was completely broken in the half-cutting process.

(Example b. When the cutting edge of the die and punch used in the half-cutting process is rounded)
Next, samples of processed products were created by the method shown in FIGS. 5 and 11, with the shoulder portions (ie, cutting edges) of the die and punch used in the half-cutting process being formed into an R shape having a predetermined radius of curvature. Zn-6%Al-3%Mg (mass ratio) alloy with a plate thickness of 1.4 to 4.5 mm and a coating weight of 90 g/m ² (one side) or 190 g/m ² (one side) as a plated steel sheet. A plated steel plate was used. The half-cutting process was performed using a round die with an inner diameter of 85.00 mm and a punch whose diameter was changed depending on the clearance between the die and the punch, and the plated steel plate was held by a plate holder. The finishing cutting process uses an R-shaped die with a shoulder (i.e., cutting edge) with a predetermined radius of curvature, and a punch whose diameter is changed according to the clearance between the die and punch, and the plated steel plate is held by a plate holder. I went.

For each sample, flatness evaluation, burr evaluation, and step evaluation were performed in the same manner as in Example a above, and the number of days for red rust occurrence was determined by an atmospheric exposure test. The results of Example b are shown in Table 2.

As shown in Table 2, in Examples b1 to b19, the residual length L of the plating component is 0.70 times or more of the plate thickness t1 at the cut end of the processed product, and the sag Z appearing in the plate thickness direction is was less than 0.10 times the plate thickness t1 of the cut end of the processed product. The length of the fractured surface of the cut end was all 1.0 mm or less, and Examples b1 to b19 exhibited good corrosion resistance for 60 days until red rust appeared. In Examples b1 to b13 and b15 to b19, the size of the sagging X appearing in the planar direction was less than 0.30 times the plate thickness t1 at the cut end of the processed product. In Examples b1 to b14, b16, and b17, the remaining length L of the plating component is 0.80 times or more of the plate thickness t1 at the cut end of the processed product, and the fracture surface length (W1) is 0.5 mm or less. It showed good corrosion resistance for 90 days or more until red rust appeared. Further, in Example b16, after finishing punching, a coining process was performed to form a coining surface with an R surface in which the length of the side to be crushed (width of the coining surface) was 0.6 mm. In Example b17, after finishing punching, coining processing was performed to form a C-plane coining surface chamfered at an angle of 45° with the length of the crushed side (width of the coining surface) being 1.0 mm. The fracture surface length (W2) after the coining process was smaller than that of the other examples. The absolute value of the difference between the die diameter D ₃₁ for half-cutting and the die diameter D ₃₂ for finish cutting |D ₃₂ −D ₃₁ | was set to 0.05 mm in Examples b1 to b17, and was set to 0.05 mm in Example b18. The diameter was zero (the diameter D ₃₁ and the diameter D ₃₂ were the same), and in Example b19 it was 1.00 mm, but in both cases, the step difference on the end face was 0.5 mm or less.

Note that the cut ends of Examples b1 to b15, b18, and b19 have a sag, a sheared surface, and a fracture surface in order in the thickness direction, and the cut ends of Examples b16 and b17 have a sag in the thickness direction. Based on the above-mentioned characteristics, it was confirmed from the external appearance that it had a sag, a sheared surface, a fractured surface, and a coined surface in that order.

On the other hand, in Comparative Examples b1, b2, b4, b6 to b8, b11, and b13, the remaining length L of the plating layer component was less than 0.70 times the plate thickness t1 at the cut end of the processed product. The number of days until red rust appeared on the cut end was less than 60 days, and the corrosion resistance was inferior compared to the examples. Further, in Comparative Examples b1 and b4, the size of the sag Z appearing in the thickness direction was 0.10 times the thickness t1 of the cut end of the processed product, and therefore sufficient flatness could not be obtained. Comparative example b5 employs a large negative clearance in the half-cutting process, but the press machine stopped due to excessive load during the half-blanking process using a 750 kN mechanical press. Comparative Examples b9 and b10 both showed good corrosion resistance for 90 days or more until red rust appeared on the cut ends, but large burrs of 0.2 mm or more were generated on the cut ends. In Comparative Examples b3 and b12, the plated steel plates were completely broken in the half-cutting process because the negative clearance between the die and the punch was not sufficient in the half-cutting process.

According to the above, in a cutting process in which a half-cutting process is performed, followed by a finishing cutting process, regarding the shape of the cut end, the remaining length L of the plating component is 0.70 times the plate thickness t1 of the cut end of the workpiece. It was confirmed that by doing the above, a cut end having good corrosion resistance could be obtained. In addition, by making the sagging Z that appears in the thickness direction of the cut edge less than 0.10 times the plate thickness t1 of the cut edge of the processed product, the product can be manufactured without increasing the flange size unnecessarily when screwing. was confirmed to be obtained.

Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

1 Processed product 2 First element 6 Second element 7 Pad 8 Coining block 9 Element 10 Body 11 Projection 12 Flange 13 Cut end 13a Top surface 13b Sag 13c Sheared surface 13d Fractured surface 13e Burr 13f Plating layer 13g Corner 13h Coining surface 13j Extension surface 13k Bottom surface 20 Flange element body 20a Removed portion 31 First die 32 Second die 41 First punch 42 Second punch 61 Outer die 63 Inner die 65 Punch 70 Vertical wall surface 71 Bottom wall surface 72 Press For now 101 Side wall 103 Top wall 121 Screw hole 123 Screw 900, 910A, 910B, 910C Flat washer 911, 931 Teeth 940 Plate

Claims (5)

A method for manufacturing a processed product using a plated steel plate having a plating layer on the surface as a material and having a cut end, the method comprising:
Using the first die and the first punch in which the clearance between the first die and the first punch is set to a negative clearance, the cut portion of the first element body formed from the material is cut in half in the thickness direction. a half-cutting process,
Using a second die and a second punch, finish cutting the half-cut first element body from the same direction as the half-cutting to obtain a processed product having a cut end along the plate thickness direction. cutting process;
including;
When the cut end is formed on the outer circumferential side of the workpiece, the inner diameter _D32 of the second die is equal to or larger than the inner diameter _D31 of the first die, and the cut end is formed on the inner side of the workpiece. In the case where the outer diameter _d32 of the second die is equal to or less than the outer diameter _d31 of the first die,
The plate thickness of the cut portion of the first element body is t1, and the remaining plate thickness of the cut portion after the half-cutting step is t2,
In the half cutting step,
The clearance _C31-41 between the first die and the first punch satisfies the following formula (a1),
The radius of curvature R1 of the cutting edge of the first die satisfies the following formula (a 2 ),
The pushing amount D of the first die or the first punch with respect to the cut portion of the first element satisfies the following formula (a3),
The distance C _PD between the first die and the first punch at the bottom dead center satisfies the following formula (a4),
In the finishing cutting step,
The clearance _C32-42 between the second die and the second punch satisfies the following formula (a5),
A method for manufacturing a processed product, wherein the radius of curvature R2 of the cutting edge of the second die satisfies the following formula (a6).
-0.25×t1≦C _31-41 ≦-0.01...(a1)
0.10×t1≦R1≦0.50×t1 (a2)
D≧0.70×t1...(a3)
C _PD ≧0.20 ... (a4)
0.01≦C _32-42 ≦0.2×t2...(a5)
0.25≦R2≦1.50×t2...(a6)
Here, the units of C _31-41 , C _PD , C _32-42 and R2 are mm. A method for manufacturing a processed product using a plated steel plate having a plating layer on the surface as a material and having a cut end, the method comprising:
Using the first die and the first punch in which the clearance between the first die and the first punch is set to a negative clearance, the cut portion of the first element body formed from the material is cut in half in the thickness direction. a half-cutting process,
Using a second die and a second punch, the half-cut first element body is finished cut in the same direction as the half-cutting, and the processed product has a cut end whose cut surface is along the plate thickness direction. A finishing cutting process to obtain
including;
When the cut end is formed on the outer circumferential side of the workpiece, the inner diameter _D32 of the second die is equal to or larger than the inner diameter _D31 of the first die, and the cut end is formed on the inner side of the workpiece. In the case where the outer diameter _d32 of the second die is equal to or less than the outer diameter _d31 of the first die,
The plate thickness of the cut portion of the first element body is t1, and the remaining plate thickness of the cut portion after the half-cutting step is t2,
In the half cutting step,
The clearance _C31-41 between the first die and the first punch satisfies the following formula (b1),
The radius of curvature R11 of the cutting edge of the first die satisfies the following formula (b2-1),
The radius of curvature R12 of the cutting edge of the first punch satisfies the following formula (b2-2),
The pushing amount D of the first die or the first punch with respect to the cut portion of the first element satisfies the following formula (b3),
The distance C _PD between the first die and the first punch at the bottom dead center satisfies the following formula (b4),
In the finishing cutting step,
The clearance _C32-42 between the second die and the second punch satisfies the following formula (b5),
The curvature radius R2 of the cutting edge of the second die satisfies the following formula (b6).
-0.35×t1≦C _31-41 ≦-0.10×t1...(b1)
0.10×t1≦R11≦0.65×t1 (b2-1)
0.10×t1≦R12≦0.65×t1 (b2-2)
D≧0.70×t1...(b3)
C _PD ≧0.20...(b4)
0.01≦C _32-42 ≦0.2×t2...(b5)
0.25≦R2≦1.50×t2...(b6)
Here, the units of C _31-41 , C _PD , C _32-42 and R2 are mm. The processed product obtained in the finishing cutting step is used as a second element body,
Manufacturing a processed product according to claim 1 or 2 , further comprising a coining step of pressing a corner of the cut end of the second element against a pad to obtain a processed product in which a coining surface is formed on the corner. Method. When a cut end is formed on the outer peripheral side of the processed product, the absolute value of the difference between the inner diameter D ₃₁ of the first die and the inner diameter D ₃₂ of the second die |D ₃₂ −D ₃₁ | .00mm or less,
When a cut end is formed on the inner side of the workpiece, the absolute value of the difference between the outer diameter d ₃₁ of the first die and the outer diameter d ₃₂ of the second die |d ₃₂ −d ₃₁ | The method for manufacturing a processed product according to any one of claims 1 to 3 , wherein the thickness is 1.00 mm or less. The method for manufacturing a processed product according to any one of claims 1 to 4 , further comprising a preparation step of forming a first element from a flat plated steel plate before the half-cutting step.

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