JP6729174B2 - Shearing method - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention can form a sheared surface having excellent surface properties when manufacturing metal members used in automobiles, home appliances, building structures, ships, bridges, construction machines, various plants, penstocks, etc. by shearing. The present invention relates to a shearing method.

BACKGROUND ART Shearing is often used for manufacturing metal members used in automobiles, home appliances, building structures, ships, bridges, construction machines, various plants, pen stocks, and the like. FIG. 1 schematically shows the mode of shearing. FIG. 1(a) schematically shows a mode of shearing for forming a hole in a work material, and FIG. 1(b) schematically shows a mode of shearing for forming an open cross section in the work. ..

In the shearing process shown in FIG. 1A, the workpiece 1 is placed on the die 3 and the punch 2 is pushed in the downward direction 2a to form a hole in the workpiece 1. In the shearing process shown in FIG. 1B, the work material 1 is placed on the die 3, and the punch 2 is similarly pushed in the downward direction 2a to form an open cross section in the work material 1.

As shown in FIG. 2, the sheared surface 9 of the processed material 10 formed by the shearing processing is usually the sagging 4, which is formed on the upper surface 8a of the sheared surface 9 when the material to be processed is pressed by a punch. The work piece 1 is drawn into the gap between the punch and the die and locally stretched to form a sheared surface 5, and the cut surface 6 formed by breaking the work piece 1 drawn into the gap between the punch and the die. (Breaking angle θ with respect to the punch direction) and burrs 7 formed on the lower surface 8b of the work material 10 when the work material 1 drawn into the gap between the punch and the die breaks and separates from the work material 10. It

Generally, the sheared surface has inferior surface properties compared to the machined surface, and for example, stretch flange cracks (cracks that occur in the sheared surface during press working after shearing) are easily generated, and the fatigue strength is low. Moreover, there are problems such as low hydrogen embrittlement resistance.

Many technologies have been proposed to solve the problems of the sheared surface, but these technologies are large and the shape and structure of the punch and die are devised to improve the surface properties of the sheared surface (stretch flange resistance, fatigue resistance, fatigue resistance). (For example, refer to Patent Documents 1 to 3) and a surface property (fatigue strength, hydrogen embrittlement resistance property) of the sheared surface by subjecting the sheared surface to treatment (shaving or coining). Etc.) (see, for example, Patent Documents 4 to 6).

However, there is a limit to the improvement of the surface properties of the sheared surface in the technology of devising the shape and structure of the punch and die, and in the technology of processing the sheared surface, the productivity is increased by one step. Decrease and manufacturing cost rises. In particular, in the cantilever type shearing technique shown in FIG. 1(b), there is a limit in improving the surface property of the sheared surface.

JP, 2009-051001, A JP, 2014-231094, A JP, 2010-036195, A JP, 2008-018481, A JP, 2011-218373, A JP, 2006-082099, A

The present invention, in view of the current state of the shearing technology, even when the strength of the workpiece is high, a processed material having a sheared surface having an excellent surface property, with high productivity, and an object thereof is to obtain at low cost. An object of the present invention is to provide a shearing method that solves the problem.

The present inventors diligently studied a method for solving the above problems. As a result, in the shearing process of forming a sheared surface with an open cross-section on the work material, the cutting material is constrained so as to oppose the processing material, the restrained state is maintained, and the end surface of the cutting material is sheared. By rubbing against the processed surface, it is possible to form a sheared surface with a small residual stress and excellent surface properties in the processed material (product), which contributes to improved productivity and reduced manufacturing costs. I found it.

The present invention has been made based on the above findings, and the summary thereof is as follows.

(1) In a shearing method of punching out a non-product part of a work material placed on a die,
(I) After punching, the punched material (non-product portion) is constrained by a punch punched from the punched material and a back pressure pin to oppose the processed material (product portion),
(Ii) A shearing method, which comprises rubbing the end surface of the blank into the sheared surface of the processed material in the opposing state.

(2) The shearing method according to (1) above, wherein a projection for restraining the punching material is present on one or both surfaces of the punch and the back pressure pin for restraining the punching material.

(3) The shearing according to (2) above, wherein the closest distance between the protrusion and the die on which the processed material is placed is 2t (t (mm): thickness of the processed material) or less. Processing method.

(4) The punch and the back pressure pin for constraining the punched material, and the pair of punch and the back pressure pin having protrusions for restraining the punched material on one or both surfaces of the punch and the back pressure pin are processed materials. The shearing method according to (1) above, which is integrally or separately provided on the opposite side of the die on which is mounted.

(5) The distance between the pair of punches and the back pressure pins having the projections for restraining the blank and the die for mounting the workpiece is 2t (t (mm): thickness of the workpiece) or less. The shearing method according to (4) above.

(6) The protrusions are present in the form of (a) being continuously connected, or (b) being dot-shaped, arc-shaped, or intermittently chained in a one-dot chain line. The shearing method according to any one of (5).

(7) The shearing method according to any one of (1) to (6), wherein the protrusion has a height of 10 to 1000 μm.

(8) The shearing method according to any one of (1) to (7), wherein the width of the protrusion is 10 to 1000 μm.

(9) In a shearing method of punching out a non-product part of a work material placed on a die,
(I-1) After punching, place the side of the die on which the blank (non-product part) is placed, the side of the holder that fixes the blank (non-product part) on the die, or the blank (non-product part). On the side of the punched punch, in the restrained state of restraining the work material, further punching the non-product part of the work material,
(I-2) After the punching, in the restrained state, the punched material (non-product portion) is restrained by the punch and the back pressure pin punched out of the punched material to oppose the processed material (product portion),
(Ii) A shearing method, which comprises rubbing the end surface of the blank into the sheared surface of the processed material in the opposing state.

(10) A side surface of a die on which the blank (non-product portion) is placed, a side surface of a holder that fixes the blank (non-product portion) on the die, or a punch punched from the blank (non-product portion). The shearing method according to (9) above, wherein the distance between the side surface and the die on which the processed material is placed is 2 t (t (mm): thickness of the processed material) or less.

(11) In any one of the above (1) to (10), the distance between the die and the punch is set within a range in which the angle of the fracture surface of the processed material is 3° or more with respect to the punch traveling direction. The shearing method described.

(12) The shearing method according to any one of (1) to (11), wherein rubbing between the end surface of the blank and the sheared surface of the processed material is stopped midway.

(13) The shearing method according to any one of (1) to (12), wherein the work material is a steel plate having a tensile strength of 980 MPa or more.

(14) The shearing method according to any one of (1) to (12), wherein the material to be processed is a laminated steel plate including a steel plate having a tensile strength of 980 MPa or more.

According to the present invention, it is possible to obtain a processed material having a sheared surface having excellent surface properties with high productivity and at low cost even when the strength of the processed material is high.

It is a figure which shows the aspect of a shearing process typically. (A) shows typically the mode of shearing which forms a hole in a processed material, and (b) shows typically the mode of shearing which forms an open section in a processed material. It is a figure which shows typically the aspect of the shearing process surface in a processed material. It is a figure which shows one aspect|mode of a cantilever type shearing process. It is a figure which shows the aspect which carried out the shearing process of the to-be-processed material by the shearing process shown in FIG. It is a figure which shows the aspect which pushes up a blank and pushes it up in the state as it was, and rubs the end surface of the blank against the sheared surface of the blank. It is a figure which shows the aspect which pushes up the cut material to the top of the processed material, and rubs the end surface of the cut material with the shearing processed surface of the processed material in the state of having been drawn. The outer peripheral portion of the work material that is not a product is sandwiched by a punch having one or more projections on the surface that contacts the work material and a back pressure pin that has one or more projections on the surface that contacts the work material. It is a figure which shows the aspect which punches out the said outer peripheral part. It is a figure which shows the aspect which pushes up the punching material in the punched state after the punching shown in FIG. 7, and rubs the end surface of the punching material with the sheared surface of the working material. FIG. 8 is a diagram showing a mode in which, after the punching shown in FIG. 7, the punched material in the punched state is pushed up to above the processed material and the end face of the punched material is rubbed against the sheared surface of the processed material. A connecting punch, in which an outer peripheral portion of the material to be processed, which is not a product, is connected to a punch having one or more protrusions on the surface contacting the material to be processed, and a punch having a flat surface contacting the material to be processed, and a material to be processed. A back pressure pin having one or more protrusions on its surface that abuts against the work piece is sandwiched by a back pressure pin having a flat surface that abuts the workpiece, and the outer peripheral portion is punched out. It is a figure. It is a figure which shows the aspect which pushes up the punching material in the punched state after the punching shown in FIG. 10, and rubs the end surface of the punching material with the shearing surface of the working material. The outer part of the outer peripheral part, which is not the product of the workpiece, is sandwiched between the holder that has one or more protrusions on the surface that contacts the workpiece and the die that has one or more protrusions on the surface that contacts the workpiece. Then, the product part of the work piece is sandwiched between a holder with a flat surface for contacting the work piece and a die with a flat surface for contacting the work piece, and the punch is placed between the holder and the holder. It is a figure which shows the aspect which punches out the inner side part (part which is not made into a product) of the outer peripheral part of a processed material. After punching shown in FIG. 12, the punched material is pushed up in the punched state, and the end surface of the punched material is rubbed simultaneously with the sheared surface of the outer portion of the outer peripheral portion of the workpiece and the sheared surface of the workpiece. FIG. After punching shown in FIG. 12, one end surface of the blank is constrained by the side surface of the die that holds the outer portion of the outer peripheral portion that is not the product of the workpiece, and the blank is pushed up in the constrained state It is a figure which shows the aspect which rubs the other end surface of the. It is a figure which shows the aspect which punches out the outer side part of the outer peripheral part which is not made into a product of a workpiece. After punching shown in FIG. 15, before punching the inner portion of the outer peripheral portion which is not the product of the work material, on the side surface of the punch punching the outer portion of the outer circumferential portion, the inner portion of the outer peripheral portion which is not the product of the work material It is a figure which shows the aspect which punches out this inner part in the state which restrained and. It is a figure which shows the aspect which punches out the inner side part of the outer peripheral part which is not made into a product of a workpiece in the restraint state shown in FIG. After punching shown in FIG. 17, one end surface of the punched material is brought into contact with the side surface of the punch punched at the outer side of the outer peripheral portion which is not the product of the workpiece to restrain the punched material, and the punched material is punched in the restrained state. It is a figure which shows the aspect which pushes up a material and rubs the other end surface of the punched material with the shearing surface of a processed material (product). It is a figure which shows the aspect which punches out the outer side part of the outer peripheral part which is not made into a product of a workpiece. After punching shown in FIG. 19, before punching out the inner part of the outer peripheral part which is not the product of the work material, on the side surface of the die punched out of the outer part of the outer peripheral part, the inner part of the outer peripheral part which is not the product of the work material It is a figure which shows the aspect which punches out this inner part in the state which restrained and. It is a figure which shows the aspect which punches out the inner side part of the outer peripheral part which is not made into a product of a workpiece in the restraint state shown in FIG. After the punching shown in FIG. 21, one end surface of the punched material is brought into contact with the side surface of the die having punched out the outer portion of the outer peripheral portion which is not the product of the workpiece to restrain the punched material, and the punched material is punched in a restrained state. It is a figure which shows the aspect which pushes up a material and rubs the other end surface of the punched material with the shearing surface of a processed material (product). It is a figure which shows the aspect which punches out the outer side part of the outer peripheral part which is not made into a product of a workpiece. After punching shown in FIG. 23, before punching the inner part of the outer peripheral part which is not the product of the work material, the outer part of the outer peripheral part is pressed against the die and fixed to the side surface of the holder, and the outer peripheral part which is not the product of the work material. It is a figure which shows the mode which punches out this inner side part in the state which restrained the inner side part and was restrained. It is a figure which shows the aspect which punches out the inner side part of the outer peripheral part which is not made into a product of a workpiece in the restraint state shown in FIG. After punching as shown in FIG. 25, one end surface of the punched material is pressed against the side surface of the holder that presses the outer portion of the outer peripheral portion against the die to abut the side surface of the holder to restrain the punched material. It is a figure which shows the aspect which pushes up and rubs the other end surface of the punched material on the shearing surface of the processed material used as a product. It is a figure which shows the basic concept of this invention typically. (A) schematically shows the basic concept of shearing, and (b) schematically shows the basic concept of rubbing. It is a figure which shows typically the rubbing mechanism of the end surface of a blank and the shearing surface of a processed material. (A) shows the contact surface of the fracture surface at the start of rubbing, and (b) shows the plastic working area at the end of rubbing. It is a figure which shows an example of the vertical cross-sectional form of the shearing surface of a processed material. (A) shows the vertical cross-sectional form of the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm) of the work piece x 0.40, and (b) shows the die The vertical sectional form of the sheared surface is shown when the punch interval d (mm) is the thickness t (mm) of the material to be processed x 0.20. It is a figure which shows an example of the vertical cross-sectional form of the shearing process surface of another process material. (A) shows the vertical cross-sectional form of the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm) x 0.05 of the work material, and (b) shows the die The vertical cross-sectional morphology of the sheared surface when the punch interval d (mm) is the thickness t (mm) of the material to be processed x 0.10. It is a figure which shows the measurement position of the residual stress in a shearing process surface. It is a figure which shows the residual stress distribution in a shearing process surface when the space|interval d (mm) of a die and a punch is thickness t (mm) x 0.05 of a to-be-processed material. It is a figure which shows the residual stress distribution in a shear processing surface in case the space|interval d (mm) of a die and a punch is thickness t (mm) x 0.10. It is a figure which shows the residual stress distribution in a shearing process surface when the space|interval d (mm) of a die and a punch is thickness t (mm) x0.20 of a to-be-processed material. It is a figure which shows the residual stress distribution in a shearing process surface when the space|interval d (mm) of a die and a punch is thickness t (mm) x0.40 of a to-be-processed material. It is a figure which shows the relationship between the fracture surface angle (fracture angle) and the residual stress reduction amount. It is a figure which shows the fatigue characteristic measured by the flat plate bending fatigue test.

The shearing method of the present invention (hereinafter sometimes referred to as “the present invention method I”) is a shearing method of punching out a non-product portion of a workpiece placed on a die with a punch,
(I) After punching, the punched material (non-product portion) is constrained by a punch punched from the punched material and a back pressure pin to oppose the processed material (product portion),
(Ii) It is characterized in that the end surface of the blank is rubbed against the sheared surface of the blank in the above-mentioned opposing state.

The shearing method of the present invention (hereinafter sometimes referred to as "the present invention method II") is a shearing method of punching out a non-product portion of a workpiece placed on a die with a punch,
(I-1) After punching, place the side of the die on which the blank (non-product part) is placed, the side of the holder that fixes the blank (non-product part) on the die, or the blank (non-product part). On the side of the punched punch, in the restrained state of restraining the work material, further punching the non-product part of the work material,
(I-2) After the punching, in the restrained state, the punched material (non-product portion) is restrained by the punch and the back pressure pin punched out of the punched material to oppose the processed material (product portion),
(Ii) It is characterized in that the end surface of the blank is rubbed against the sheared surface of the blank in the above-mentioned opposing state.

First, the method I of the present invention will be described with reference to the drawings.

FIG. 3 shows a cantilever type shearing process, and FIG. 4 shows a cantilever type shearing process on the workpiece.

In the shearing machine shown in FIG. 3, the distance d (mm) between the die 12 and the punch 17 is such that the fracture angle θ of the fracture surface (see “6” in FIG. 2) of the sheared surface of the workpiece is 3 with respect to the punch direction. It is set to be above °.

In the method I of the present invention and the method II of the present invention (hereinafter, may be collectively referred to as the “method of the present invention”), the distance d (mm) between the die and the punch is the breaking angle of the fracture surface on the sheared surface of the processed material. A range in which θ is 3° or more with respect to the punching direction, that is, the fracture surface and the shoulder surface of the blank are abutted against each other at a required angle, and a compressive plastic deformation may be applied to the surface layer of the sheared surface of the blank. It is preferable to set it within a possible range. This point will be described later.

In the method of the present invention, the material to be sheared is a steel plate, a metal plate made of copper, zinc, tin, aluminum, titanium, magnesium, and an alloy based on the steel plate, or these metal plates. Is a laminated metal plate in which The material of the workpiece is not limited to a specific material as long as it can be sheared. The thickness of the work material is not limited to a specific thickness as long as it can be sheared.

The method of the present invention is particularly suitable for shearing a steel sheet having a tensile strength of 980 MPa or more and shearing a laminated steel sheet including a steel sheet having a tensile strength of 980 MPa or more. This point will be described later.

In cold shearing, the thickness of the workpiece is preferably 6.0 mm or less from the viewpoint of maintaining the shape and dimensional accuracy of the sheared product. In particular, when the shape and dimensional accuracy of the sheared product is required to be high, the thickness of the work piece is more preferably 3.0 mm or less.

As shown in FIG. 3, on one side of the machine frame 18, the work material 14 is arranged in a cantilever type shearing machine in which the back pressure pin 13 held by the elastic member 11 projects from the upper surface of the die 12 by ΔH. To do. The holder 15 is pressed by the elastic member 16 to fix the work piece 14 to the die 12 of the shearing machine, and as shown in FIG. 4, the punch 17 is pushed down while countering the back pressure of the back pressure pin 13 and sheared. A processed material 14a having a processed surface 9 is obtained.

Up to this point, the usual shearing process has been performed, but in the method I of the present invention, as shown in FIG. 5, the repulsive force of the elastic member 11 is utilized to pull out the blank 19 held by the back pressure pin 13. In the state in which it is held, it is pushed up and the end surface 20 of the blank 19 is rubbed against the sheared surface 21 of the blank 14a.

During this rubbing, the blank 19 is constrained by the machine frame 18 so as to oppose the workpiece 14a. Under this restrained state, the end surface 20 of the blank 19 is sheared. It will rub against the surface 21.

As shown in FIG. 2, the sheared surface of the processed material is usually composed of a sag 4, a sheared surface 5, a fractured surface 6 and a burr 7. When the end surface 20 of the blank 19 is rubbed against the sheared surface 21 of the processed material 14a in the above-mentioned constrained state using 21 as a tool for adjusting, the surface of the sheared surface 21 of the processed material 14a is plastically deformed by compression. Is added, the residual stress on the sheared surface 21 is greatly reduced and becomes uniform.

As a result, the surface properties of the sheared surface 21 of the processed material 14a are significantly improved, and the fatigue characteristics and the hydrogen embrittlement resistance of the processed material 14a are significantly improved.

The rubbing of the end surface 20 of the blank 19 and the sheared surface 21 of the blank 14a may be stopped in the middle as shown in FIG. 5, or as shown in FIG. You may push up on 14a and may perform it over the whole surface 21 of a shearing process. The presence of "burrs" on the sheared surface 21 lowers the stretch-flange formability, so the rubbing may be performed within a range in which "burr" does not occur due to rubbing.

The shape of the blank or the shape of the processed material is not limited to a particular shape as long as it is possible to rub the end surface of the blank and the sheared surface of the contour surface of the processed material.

Another aspect of the method I of the present invention will be described with reference to FIGS. 7 to 9.

FIG. 7 shows a punch having one or more protrusions on the surface abutting the workpiece and a back pressure having one or more protrusions on the surface abutting the workpiece on the outer peripheral portion of the workpiece that is not a product. A mode is shown in which the outer peripheral portion is punched by being pinched by a pin. FIG. 8 shows a mode in which, after the punching shown in FIG. 7, the punched material is pushed up in the punched state and the end face of the punched material is rubbed against the sheared surface of the processed material, and FIG. 9 shows the punched material shown in FIG. After that, in the punched state, the punched material is pushed up to above the processed material, and the end face of the punched material is rubbed against the sheared surface of the processed material.

In the shearing process shown in FIG. 7, the outer peripheral portion 14b of the workpiece is punched with one or more protrusions 22 on the surface that contacts the workpiece, and one or more punches on the surface that contacts the workpiece. It is punched by being sandwiched by the back pressure pin 13 having the protrusion 22.

After the punching, as shown in FIG. 8, the punched material 19 (the outer peripheral portion 14b of the work piece) is punched out, and is sandwiched between the punch 17 having the projection 22 and the back pressure pin 13 and pushed up to remove the punched material. The end surface 20 of 19 is rubbed against the sheared surface 21 of the processed material 14a.

Further, after the punching, as shown in FIG. 9, the punched material 19 (the outer peripheral portion 14b of the workpiece) is punched, and is sandwiched between the punch 17 having the projection 22 and the back pressure pin 13 to obtain the worked material. It is pushed up above 14a, and the end surface 20 of the blank 19 is rubbed against the sheared surface 21 of the worked material 14a.

Since the punched material 19 (the outer peripheral portion 14b of the workpiece) is sandwiched between the punch 17 having the projection 22 and the back pressure pin 13 and is restrained so as to oppose the worked material, the punched material 19 and the end surface 20 are machined. By rubbing the sheared surface 21 of the material 14a, a compressive plastic deformation can be applied to the surface layer of the sheared surface 21 of the material 14a. As a result, the surface properties of the sheared surface 21 of the processed material 14a are significantly improved.

7 to 9, the outer peripheral portion 14b, which is not a product of the workpiece, is provided with a punch 17 having one or more protrusions 22 on the surface contacting the workpiece, and one on the surface contacting the workpiece. Although the above-described embodiment is shown in which the back pressure pin 13 having the protrusions 22 is sandwiched and punched, the punched material (the outer peripheral portion 14b of the workpiece) is firmly clamped and restrained so as to oppose the worked material. As long as the plastic deformation of compression can be applied to the surface layer of the sheared surface of the processed material by rubbing the end surface of the processed material with the sheared surface of the processed material, the protrusion is provided on only one of the punch and the back pressure pin. May be.

The cross-sectional shape of the protrusion provided on the surface of the punch and/or the back pressure pin that contacts the work piece is such that the punched material (outer peripheral portion of the work piece) is firmly sandwiched and constrained to oppose the work piece It is not limited to a particular cross-sectional shape as long as the plastic deformation of compression can be applied to the surface layer of the sheared surface of the processed material by rubbing the end surface of the processed material and the sheared surface of the processed material. For example, the cross-sectional shape of the protrusion may be V-shaped, U-shaped, convex, or the like.

The height of the protrusions (the height in the direction perpendicular to the sandwiching surface of the work material) is usually preferably as high as possible in terms of securing the sandwiching force and the restraining force against the processed material, but if it is too high, There is a limit to the height of the protrusion because the abrasion and wear of the protrusion progress rapidly and the pressing force required for holding the workpiece is increased. According to the test results of the present inventors, the height of the protrusion is preferably 10 to 1000 μm. More preferably, it is 10 to 500 μm.

When protrusions are provided on both the surface of the punch that contacts the workpiece and the surface of the back pressure pin that contacts the workpiece, the cross-sectional shapes of the protrusions need not be the same. Firmly sandwich the blank (peripheral part of the workpiece) and restrain it so as to oppose the blank. When the end surface of the blank and the sheared surface of the blank are rubbed, the sheared surface of the blank The cross-sectional shape of the protrusion may be different between the punch and the back pressure pin as long as the plastic deformation of compression can be applied to the surface layer.

The shape of the projection provided on the surface of the punch and/or the back pressure pin that comes into contact with the work material in the circumferential direction of the outer peripheral portion is such that the punched material (the outer peripheral portion of the work material) is firmly sandwiched, and it opposes the work material. There is no particular limitation as long as it is possible to apply a plastic deformation of compression to the surface layer of the sheared surface of the processed material by rubbing the end surface of the blank and the sheared surface of the processed material.

The circumferential shape of the above-mentioned outer peripheral portion of the projection that holds the outer peripheral portion which is not a product of the work material and is constrained so as to oppose the processed material is, for example, a shape in which the projections having a desired cross-sectional shape are continuously connected or The projections having a required cross-sectional shape may be in the form of a dot, an arc, or a chain of dots. When the projections are point-shaped projections, the equivalent circle diameter of the projections is preferably 10 to 1000 μm in terms of suppressing wear and wear of the projections. More preferably, it is 10 to 500 μm. When the protrusion is an arc-shaped protrusion, the width of the protrusion is preferably 10 to 1000 μm for the same reason. More preferably, it is 10 to 500 μm.

The number of rows (rows) in the width direction of the outer peripheral portion of the projections (projection rows) provided on the surface of the punch and/or the back pressure pin that abuts the material to be processed is firm for the punched material (outer peripheral portion of the workpiece). As long as it is possible to apply a plastic deformation of compression to the surface layer of the sheared surface of the processed material, by sandwiching it in place, restraining it against the processed material, and rubbing the end surface of the blank and the sheared surface of the processed material. The number is not limited to a specific number (number of columns).

The number (row number) of the protrusions (projection rows) in the width direction of the outer peripheral portion may be appropriately set according to the width of the blank (the outer peripheral portion of the workpiece). The number (row number) of the protrusions (rows of protrusions) is preferably 2 or more in that the blank material (outer peripheral portion of the material to be processed) is firmly sandwiched and constrained so as to strongly oppose the processed material. Further, the number of projections (rows of projections) (row number) may be different between the punch surface and the back pressure pin surface.

On the surface of the punch that comes in contact with the work piece, the position of the protrusion closest to the die firmly clamps the punched material (outer peripheral portion of the work piece) and restrains it so as to oppose the worked material. As long as the plastic deformation of compression can be sufficiently applied to the surface layer of the sheared surface of the processed material by rubbing the end face of the processed material with the sheared surface of the processed material, it is not limited to a specific position, From the viewpoint of forming a sheared surface having excellent properties, the position of the protrusion is preferably as short as the distance from the die.

On the surface of the punch that comes into contact with the work material, the position of the protrusion closest to the die is that the work material has a thickness t (mm) because it forms a sheared surface having excellent surface properties. Also related. The position of the protrusion, that is, the closest distance between the protrusion and the die on which the workpiece is placed is preferably 2t (t (mm): thickness of the workpiece) or less, and more preferably 1t or less.

In the method I of the present invention, the surface on which the projection is provided (punch surface and/or back pressure pin surface), and the cross-sectional shape, size, form, number (row number), and position of the projections depend on the mode of shearing. And set appropriately.

In the method of the present invention, by rubbing the end surface of the blank and the sheared surface of the workpiece, the blank functions as a tool for applying a plastic deformation of compression to the surface layer of the sheared surface of the workpiece, The residual stress on the sheared surface is substantially reduced and uniformized, and the surface properties of the sheared surface of the processed material are greatly improved. As a result, fatigue properties, hydrogen embrittlement resistance, stretch flangeability, etc. are improved.

By rubbing the end surface of the blank and the sheared surface of the processed material, the effect of improving the surface property of the sheared surface of the processed material is that the distance d (mm) between the die and the punch is A range in which the angle of the fracture surface is 3° or more with respect to the punch direction (when the fracture surface and the shoulder surface of the blank are abutted against each other at a required angle, compressive plastic deformation may be applied to the surface layer of the sheared surface of the workpiece. It will be better if you set it in the (possible range). This point will be described later.

As described above, the method I of the present invention, which is shown in FIGS. 7 to 9 as an embodiment, is a shearing method for punching a plate-shaped workpiece in the thickness direction.
(I) The outer peripheral portion of the material to be processed, which is pressed and fixed on the die with a holder,
(a1) (a1-1) It is sandwiched by a projecting surface punch that has one or more projections on the lower surface that contacts the work material, and (a1-2) a flat back pressure pin that has a flat upper surface that contacts the work material. ,
(b1) (b1-1) A flat punch having a flat lower surface that abuts the work piece, and (b1-2) a back punch pin having one or more projections on the surface that abuts the work piece. Or
(c1) (c1-1) Protrusion surface punch having one or more protrusions on the surface contacting the work material, and (c1-2) Protrusion spine having one or more protrusions on the surface contacting the work material. Hold with a pressure pin,
(Ii) (a1), (b1), or, the outer peripheral portion of the workpiece sandwiched in (c1) is punched by the cooperation of the punch and the back pressure pin, then,
(Iii) The punched material is pushed up as it is, and the end surface of the punched material is rubbed against the sheared surface of the processed material.

Another aspect of the method I of the present invention will be described with reference to FIGS.

FIG. 10 shows a connection punch in which an outer peripheral portion of a workpiece that is not a product is connected to a punch having one or more protrusions on the surface that contacts the workpiece, and a punch that has a flat surface that contacts the workpiece. , A back pressure pin having one or more protrusions on its surface that abuts the work piece, and a back pressure pin having a flat surface that abuts the work piece. The punching mode is shown.

FIG. 11 shows a mode in which, after the punching shown in FIG. 10, the blank is pushed up in the punched state and the end face of the blank is rubbed against the sheared surface of the blank.

As shown in FIG. 10, the outer peripheral portion 14b, which is not a product of the work material, is punched into a punch 17 having one or more protrusions on the surface contacting the work material, and the punch 17a having a flat surface contacting the work material. Back punching pin 13b that has a flat surface that contacts the workpiece and a backing pin 13b that has one or more protrusions on the surface that contacts the workpiece. The outer peripheral portion 14b of the material to be processed is punched out by being clamped by 13b, and by the cooperation of the connecting punch 17b and the die 12.

The punch 17 and the punch 17a and the back pressure pin 13 and the back pressure pin 13a may be firmly connected by a known connection means capable of releasing the connection. In the connection punch 17b and the connection back pressure pin 13b, the punch 17a and the back pressure pin 13a to be connected can be appropriately replaced according to the width of the outer peripheral portion of the workpiece to be punched, and the punch 17 and/or the back pressure pin 13b can be replaced. The pin 13 can be appropriately replaced depending on the degree of wear of the protrusion 22.

After the punching shown in FIG. 10, as shown in FIG. 11, the punching material 19 (outer peripheral portion 14b) sandwiched between the coupling punch 17b and the coupling back pressure pin 13b is pushed up the coupling rear surface pin 13b to oppose the processed material. In the restrained state, the end surface 20 of the blank 19 (outer peripheral portion 14b) is rubbed against the sheared surface 21 of the processed material 14a. This rubbing may be stopped in the middle as shown in FIG. 11, or may be carried out by pushing up the blank 19 (outer peripheral portion 14b) to above the processed material 14a (see FIG. 9).

As described above, since the punched material 19 (outer peripheral portion 14b) is clamped by the connecting punch 17b and the coupling back pressure pin 13b and is restrained so as to oppose the worked material, the end surface 20 of the punched material 19 and the worked material By rubbing the sheared surface 21 of 14a, it is possible to sufficiently apply the plastic deformation of compression to the surface layer of the sheared surface 21 of the processed material. As a result, the surface properties of the sheared surface 21 of the processed material 14a are significantly improved.

In FIGS. 10 and 11, the outer peripheral portion 14b of the workpiece is punched by sandwiching it with a connecting punch to which the punch 17 having the protrusion 22 is connected and a connecting back pressure pin to which the back pressure pin 13 having the protrusion 22 is connected. Although the embodiment is shown, the punched material (outer peripheral portion of the work piece) is firmly sandwiched and constrained so as to oppose the worked material, and the end surface of the punched material and the sheared surface of the worked material are rubbed to each other to form the worked material. The protrusions may be provided on only one of the punch and the back pressure pin as long as the plastic deformation of compression can be applied to the surface layer of the sheared surface.

As described above, the method of the present invention shown in FIGS. 10 and 11 is a shearing method of punching a plate-shaped workpiece in the thickness direction,
(I) On the die, the outer peripheral portion of the material to be processed, which is pressed and fixed by the holder to the product,
(a2) (a2-1) A connecting punch in which a flat surface punch having a flat upper surface that contacts the workpiece is connected to the die-side side surface of a protruding surface punch that has a projection on the lower surface that contacts the workpiece, and (a2) -2) The flat upper surface of the flat back pressure pin facing the work piece facing the protruding surface punch is flat, and the flat upper surface of the back face pin facing the work piece facing the flat surface punch is flat. Hold the back pressure pin with the connected back pressure pin,
(b2) (b2-1) A connecting punch in which another flat surface punch having a flat lower surface that contacts the workpiece is connected to the die side surface of the flat punch that has a flat lower surface that contacts the workpiece, and (b2- 2) On the side surface of the projection back pressure pin, which has a projection on the upper surface that is in contact with the work material and is opposed to the flat punch, has a flat upper surface that is in contact with the work material and that is opposed to the different flat punch. Hold the back pressure pin with the connected back pressure pin, or
(c2) (c2-1) A connecting punch in which a flat surface punch having a flat upper surface that contacts the workpiece is connected to the die-side side surface of a protruding surface punch that has a projection on the lower surface that contacts the workpiece, and (c2 -2) On the die-side side surface of the projection back pressure pin that has a projection on the upper surface that is in contact with the workpiece and that faces the protruding surface punch, the upper surface that is in contact with the workpiece that faces the flat punch is flat. Hold the flat back pressure pin with the connected back pressure pin,
(Ii) The outer peripheral portion of the work piece clamped in (a2), (b2), or (c2) is punched by the cooperation of the connecting punch and the connecting back pressure pin, and then,
(Iii) The punched material is pushed up as it is, and the end surface of the punched material is rubbed against the sheared surface of the processed material.

Next, a preferred embodiment for shearing when the strength of the work material is high, for example, when the strength of the work material is 980 MPa class or higher will be described.

When the strength of the work material is high, the work material escapes to the punch side during punching. When this escape phenomenon occurs, a sheared surface having excellent surface properties cannot be obtained in the processed material. In order to suppress the escape phenomenon of the work material, it is necessary to strongly restrain the work material with a die and a holder.However, when shearing is performed with a punch having a protrusion, even if the work material is strongly restrained, A phenomenon occurs in which the processed material escapes to the punch side, and a sheared surface having excellent surface properties cannot be obtained in the processed material.

12 to 14 show one embodiment of the method I of the present invention, which is preferable for shearing when the strength of the work material is high, for example, when the strength of the work material is 980 MPa or higher.

In FIG. 12, a holder having one or more protrusions on the outer surface of the outer peripheral portion which is not a product of the work material and one or more protrusions on the surface contacting the work material is provided. The outer circumference of the work piece is held by a holder that has a flat surface that contacts the work piece and a die that has a flat surface that makes contact with the work piece and that is sandwiched between the holder and the holder. The mode which punches out the inner part (part which is not made into a product) of a part is shown.

In FIG. 13, after the punching shown in FIG. 12, the punched material is pushed up in the punched state, and the end surface of the punched material is cut into the sheared surface of the outer peripheral portion of the workpiece and the sheared surface of the workpiece. A mode of simultaneously rubbing is shown.

In FIG. 14, after punching shown in FIG. 12, one end surface of the punched material is restrained by the side surface of the die that holds the outer portion of the outer peripheral portion which is not the product of the workpiece, and the punched material is restrained in the restrained state. The mode which pushes up and rubs the other end surface of the punched material to the sheared surface of the processed material is shown.

As shown in FIG. 12, the outer portion 14ba of the outer peripheral portion, which is not a product of the workpiece, is provided with a holder 15a having one or more protrusions 22 on the surface contacting the workpiece and a surface contacting the workpiece. The work material 14a, which is sandwiched by the dies 12a having one or more protrusions 22 and which is a product in the work material, has a holder 15 having a flat surface for contacting the work material and a flat surface for contacting the work material. The inner portion 14bb of the outer peripheral portion which is not a product of the workpiece is punched by the punch 17 which is sandwiched by the die 12 and arranged between the holder 15a and the holder 15.

In the shearing process shown in FIG. 12, the outer part 14ba of the outer peripheral part which is not a product of the work piece is sandwiched by the holder 15a and the die 12a, and the die 12a and the die 12 and the punch 17 cooperate to produce the work piece. Since the inner part 14bb of the outer peripheral part which is not a product is punched out, even if the strength of the work material is high, it is possible to suppress the phenomenon that the work material escapes to the punch side as much as possible, and the work material 14a (product) can be sheared at the stage of shearing. Thus, it is possible to form a sheared surface having excellent surface properties.

After the punching shown in FIG. 12, as shown in FIG. 13, the punched material 19 (the inner portion 14bb of the outer peripheral portion of the material to be processed) is pushed up by the back pressure pin 13 in the punched state to obtain the punched material 19 The end faces of the above are simultaneously rubbed with the sheared surface 21 of the outer portion 14ba of the outer peripheral portion of the workpiece and the sheared surface 21 of the workpiece 14a. Also in this case, the punched material 19 may be pushed up to above the processed material 14a.

Further, as shown in FIG. 14, after the punching shown in FIG. 12, the die 12a and the holder 15a that hold the outer portion 14ba of the outer peripheral portion which is not a product of the workpiece is pushed up to push out the punched material 19 (the workpiece One end surface 20 of the inner portion 14bb of the outer peripheral portion of the die is constrained by the side surface of the die 12a, and the other end surface 20 of the blank 19 (the inner portion 14bb of the outer peripheral portion of the workpiece) is machined in the constrained state. It may be rubbed against the sheared surface 21 of the material 14a.

In the shearing process shown in FIG. 12, when the outer portion 14ba of the outer peripheral portion which is not a product of the workpiece is sandwiched by the die 12a and the holder 15a, the escape of the workpiece is suppressed during the shearing of the workpiece. As long as it is possible to maintain the work material in a stable state and to secure the force for restraining the blank material 19 (the inner portion 14bb of the outer peripheral portion of the work material) during the rubbing shown in FIG. It suffices that either one of the holder 15a and the die 12a that hold the portion 14ba have the protrusion 22.

In the shearing process shown in FIG. 12, the scrap portions (the outer peripheral portions 14ba and 14bb that are not the product of the work material) are wide, but the outer portion 14ba of the outer peripheral portion that is not the product of the work material can be wide. Therefore, even if only one of the holder 15a and the die 12a that holds the outer portion 14ba is provided with the protrusion 22, the escape of the work material is suppressed during the shearing of the work material to stabilize the work material. It is possible to maintain the state and to secure the force for restraining the blank 19 (the inner portion 14bb of the outer peripheral portion of the workpiece) during the rubbing shown in FIG.

As a result, in the shearing process of the work material, it is possible to form a sheared surface with good shape accuracy on the work material, and to perform compression plastic processing on the surface layer of the sheared surface with good shape accuracy of the work material. Therefore, it is possible to reliably obtain a high-strength processed material having a sheared surface excellent in shape accuracy and surface properties from a high-strength processed material.

The shearing process shown in FIGS. 12 to 14 has many parts to be scrapped in one work material, but as described above, from the high strength work material, the sheared surface excellent in surface property and shape accuracy is obtained. Since it is a shearing process that can reliably obtain a high-strength processed material, it is a high-yield and highly productive shearing process as a whole.

As described above, the method I of the present invention shown in FIGS. 12 to 14 is a shearing method for punching a plate-shaped workpiece in the thickness direction,
(I) On the die, the outer peripheral portion of the material to be processed, which is pressed and fixed by the holder to the product,
(a3) (a3-1) It is sandwiched by a projecting surface punch that has one or more projections on the lower surface that contacts the work material, and (a3-2) a flat back pressure pin that has a flat upper surface that contacts the work material. ,
(b3) (b3-1) A flat punch with a flat lower surface that abuts the work piece, and (b3-2) a back punch pin having one or more projections on the surface that abuts the work piece. Or
(c3) (c3-1) Projection surface punch having one or more projections on the surface contacting the work material, and (c3-2) Projection spine having one or more projections on the surface contacting the work material. Hold with a pressure pin,
(Ii) in cooperation with the convex punch or the punch arranged between the flat punch and the holder, and the back pressure pin arranged between the convex back pressure pin or the flat back pressure pin and the die, facing the punch, Punch out the part that will not be the product inside the outer periphery of the work material,
(Iii) In the punched state, the punched material is (d1) pushed up as it is, or (d2) one end surface of the punched material is pushed up by restraining it with the side surface of the flat back pressure pin or the projection back pressure pin. The other end surface of the blank is rubbed against the sheared surface of the blank.

15 to 18 show one embodiment of the method II of the present invention, which is preferable for shearing when the strength of the work material is high, for example, when the strength of the work material is 980 MPa or higher.

FIG. 15 shows a mode of punching out the outer portion of the outer peripheral portion which is not the product of the workpiece. In FIG. 16, after punching shown in FIG. 15, before punching the inner portion of the outer peripheral portion which is not the product of the work material, the outer periphery of the outer circumferential portion is punched, and the punch side surface is not the product of the work material. A mode in which the inner part of the part is constrained and the inner part is punched out in a constrained state is shown.

FIG. 17 shows a mode of punching out the inner portion of the outer peripheral portion which is not the product of the workpiece in the restrained state shown in FIG. In FIG. 18, after the punching shown in FIG. 17, one end surface of the punched material is brought into contact with the side surface of the punch having punched out the outer peripheral portion which is not the product of the workpiece to restrain the punched material. The mode which pushes up a blank and rubs the other end surface of the blank against the shearing surface of the blank (product) is shown.

As shown in FIG. 15, the inner portion 14bb of the outer peripheral portion, which is not the product of the workpiece, is placed on the back pressure pin 13, and the punch 17 is used as a holder to press and fix it to obtain the product (working material). With the portion 14a placed on the die 12 and pressed by the holder 15 to be fixed, the punch 17a punches out the outer portion 14ba of the outer peripheral portion which is not a product.

After punching as shown in FIG. 15, as shown in FIG. 16, before punching the inner portion 14bb of the outer peripheral portion which is not the product of the workpiece, the side surface of the punch 17a in which the outer portion 14ba of the outer peripheral portion is punched is processed. The inner portion 14bb of the outer peripheral portion is restrained by abutting against the cross section 20 of the inner portion 14bb of the outer peripheral portion which is not a product, and the inner portion 14bb of the outer peripheral portion is punched by the punch 17.

As shown in FIG. 17, the punch 17 and the punch 17a are pushed down at the same time, the constraint state shown in FIG. 16 is maintained, and the inner portion 14bb of the outer peripheral portion which is not a product of the work material is collaborated by the cooperation of the punch 17 and the die 12. Punch out. Since the inner portion 14bb of the outer peripheral portion is punched out while maintaining the restrained state shown in FIG. 16, it is possible to suppress the phenomenon that the work material on the product side escapes to the punch side, and the shape of the work material (product) is reduced. It is possible to form a sheared surface with good accuracy.

While maintaining the restrained state shown in FIG. 16, the punch 17 and the die 12 cooperate to suppress the escape phenomenon of the work material when punching out the inner portion 14bb of the outer peripheral portion which is not the product of the work material. The distance between the side surface of the punch 17a and the die 12 is preferably 2t (t (mm): thickness of the work material) or less, and more preferably 1t or less.

After the punching shown in FIG. 17, as shown in FIG. 18, one end face 20 of the punching material 19 (the inner portion 14bb) is punched with an outer portion of the outer peripheral portion which is not a product of the workpiece. While maintaining the state in which the side surfaces are in contact with each other and the punched material 19 is restrained, the back pressure pin 13 is pushed up to push up the punched material 19, and the other end surface 20 of the punched material 19 is sheared by the processed material (product). Rub on the processed surface 21.

This rubbing may be stopped in the middle of pushing up, or if the "burr" due to rubbing does not occur on the sheared surface 21, the punched material 19 may be pushed up onto the worked material 14a. ..

As described above, the method II of the present invention whose embodiment is shown in FIGS. 15 to 18 is a shearing method for punching a plate-shaped workpiece in the thickness direction,
(I) The outer peripheral portion of the material to be processed, which is pressed and fixed by a holder on the die, is punched out by an outer peripheral punch,
(Ii) When the side surface of the outer peripheral punch on the die side is in contact with the punching end surface of the processed material and the processed material is restrained, the intermediate punch and the die arranged between the punch and the holder are Punch out the parts that are not to be the product,
(Iii) The punched material is punched out, that is, the die side surface of the outer peripheral punch is in contact with the punched end surface of the punched material, and the punched material is pushed up in a restrained state, and the other punched end surface of the punched material is It is characterized in that it is rubbed against the sheared surface of the processed material.

19 to 22 show another embodiment of the method II of the present invention which is preferable for shearing when the strength of the work material is high, for example, when the strength of the work material is 980 MPa or higher.

FIG. 19 shows a mode of punching out the outer portion of the outer peripheral portion which is not the product of the workpiece. In FIG. 20, after punching shown in FIG. 19, before punching the inner portion of the outer peripheral portion which is not the product of the work material, the outer periphery of the outer peripheral portion is punched, and the outer surface of the die is not the product of the work material. The inner part of the part is restrained, and the inner part is punched out in a restrained state.

FIG. 21 shows a state in which the inner portion of the outer peripheral portion which is not the product of the workpiece is punched out in the restrained state shown in FIG. In FIG. 22, after the punching shown in FIG. 21, one end surface of the punched material is brought into contact with the side surface of the die having the punched outer portion of the outer peripheral portion which is not the product of the workpiece to restrain the punched material. In this state, the blank is pushed up and the other end face of the blank is rubbed against the sheared surface of the blank (product).

As shown in FIG. 19, the outer portion 14ba of the outer peripheral portion which is not a product of the workpiece is placed on the die 12a and pressed by the holder 15a to be fixed, and the outer peripheral portion 14a is cooperated with the punch 17 and the die 12a. Punch out the outer part 14ba.

After the punching shown in FIG. 19, as shown in FIG. 20, the inner portion of the outer peripheral portion which is not the product of the workpiece is placed on the back pressure pin 13, and the product portion of the workpiece is placed on the die 12. Then, the product portion is pressed and fixed by the holder 15, and the side surface of the die 12a in which the outer portion 14ba of the outer peripheral portion is punched out is punched out before the inner portion 14bb of the outer peripheral portion which is not a product of the workpiece is punched out. The workpiece (the inner portion 14bb of the outer peripheral portion and the workpiece 14a (product) portion) is constrained by contacting the end surface 20 of the inner portion 14bb of the outer peripheral portion which is not the product of the workpiece.

While maintaining the restrained state shown in FIG. 20, the punch 17 and the die 12 cooperate to suppress the escape phenomenon of the work material when punching out the inner portion 14bb of the outer peripheral portion which is not the product of the work material. The distance between the side surface of the die 12a and the die 12 is preferably 2t (t (mm): thickness of the work material) or less, and more preferably 1t or less.

As shown in FIG. 21, the punch 17 and the die 12a are pushed down at the same time, and the constraint state shown in FIG. 20 is maintained. Punch out. While the constraint state shown in FIG. 20 is maintained and the inner portion 14bb of the outer peripheral portion is punched out by the cooperation of the punch 17 and the die 12, the phenomenon that the work material on the product side escapes to the punch side is suppressed. In the processed material (product), a sheared surface having good shape accuracy is formed.

After the punching shown in FIG. 21, as shown in FIG. 22, one end surface 20 of the blank 19 (the inner portion 14bb) has a die 12a in which the outer portion of the outer peripheral portion which is not the product of the workpiece is punched. While maintaining the state in which the side surfaces are abutted and the punched material 19 is restrained, the back pressure pin 13 is pushed up to push up the punched material 19, and the other end surface 20 of the punched material 19 is sheared by the processed material (product). Rub on the processed surface 21.

This rubbing may be stopped in the middle of pushing up, or if the "burr" does not occur on the sheared surface due to rubbing, the blank 19 may be pushed up onto the worked material.

As described above, the method II of the present invention, which shows an embodiment in FIGS. 19 to 22, is a shearing method of punching a plate-shaped workpiece in the thickness direction,
(I) The outer peripheral portion of the material to be processed, which is not a product, is pressed and fixed by a holder onto an outer die arranged outside the main die that comes into contact with a portion to be processed in the material to be processed. Punch with a punch,
(Ii) In the state in which the punch side surface of the outer die is in contact with the punching end face of the processed material and the processed material is constrained, the punch and the main die punch out the outer peripheral portion of the processed material that is not a product,
(Iii) punched material, that is, the side surface of the outer die on the main die side abuts the punched end surface of the punched material, and pushes up with the punched material constrained, and the other punched end surface of the punched material, It is characterized in that it is rubbed against the sheared surface of the processed material to be the product.

23 to 26 show another embodiment of the method II of the present invention which is preferable for shearing when the strength of the work material is high, for example, when the strength of the work material is 980 MPa or higher.

FIG. 23 shows a mode of punching out the outer portion of the outer peripheral portion which is not the product of the workpiece. In FIG. 24, after punching shown in FIG. 23, before punching out the inner portion of the outer peripheral portion which is not the product of the workpiece, the outer portion of the outer peripheral portion is pressed against the die and fixed to the side surface of the holder to be the product of the workpiece. A state in which the inner portion of the outer peripheral portion which is not defined is constrained and the inner portion is punched out in a constrained state is shown.

FIG. 25 shows a mode of punching out the inner portion of the outer peripheral portion which is not the product of the workpiece in the restrained state shown in FIG. In FIG. 26, after punching shown in FIG. 25, one end surface of the punched material is pressed against the outer side of the outer peripheral portion of the die by abutting the side surface of the fixed holder to restrain the punched material. , A mode in which the punched material is pushed up and the other end surface of the punched material is rubbed against the sheared surface of the processed material to be the product.

As shown in FIG. 23, the outer portion 14ba of the outer peripheral portion which is not the product of the work piece is placed on the die 12a and pressed by the holder 15a to be fixed, and the outer peripheral portion 14a is cooperated with the punch 17 and the die 12a. Punch out the outer part 14ba.

After the punching shown in FIG. 23, as shown in FIG. 24, the inner portion 14bb of the outer peripheral portion which is not the product of the workpiece is placed on the back pressure pin 13, and the workpiece 14a (product) portion is placed on the die 12. The die 12a and the holder that clamp the outer portion 14ba of the outer peripheral portion before punching out the inner portion 14bb of the outer peripheral portion which is not a product of the workpiece are fixed by pressing the product portion with a holder 15 and fixing. 15a is pushed down, the side surface of the holder 15a is brought into contact with the end surface 20 of the inner portion 14bb of the outer peripheral portion which is not the product of the workpiece, and the inner portion 14bb is restrained.

As shown in FIG. 25, the punch 17 and the holder 15a are pushed down at the same time to maintain the restrained state shown in FIG. 24, and the punch 17 and the die 12 cooperate with each other so that the inner portion 14bb of the outer peripheral portion which is not a product of the workpiece is processed. Punch out. Since the inner portion 14bb of the outer peripheral portion is punched out while maintaining this restrained state, the phenomenon that the work material on the product side escapes to the punch side is suppressed, and the work material 14a (product) has a high shape accuracy. A good sheared surface is formed.

With the constraint state shown in FIG. 24 maintained, the punch 17 and the die 12 cooperate with each other to suppress the escape phenomenon of the work material when punching out the inner portion 14bb of the outer peripheral portion which is not the product of the work material. The distance between the side surface of the holder 15a and the die 12 is preferably 2t (t (mm): thickness of the workpiece) or less, and more preferably 1t or less.

After the punching shown in FIG. 25, as shown in FIG. 26, the side surface of the holder 15a is brought into contact with one end surface 20 of the punched material 19 (the inner portion 14bb) to restrain the punched material 19, While maintaining, the back pressure pin 13 is pushed up and the punched material 19 is pushed up, and the other end surface 20 of the punched material 19 is rubbed against the sheared surface 21 of the worked material (product).

This rubbing may be stopped in the middle of pushing up, or if the "burr" does not occur on the sheared surface due to rubbing, the blank 19 may be pushed up onto the worked material.

As described above, the method II of the present invention whose embodiment is shown in FIGS. 23 to 26 is a shearing method of punching a plate-shaped workpiece in the thickness direction,
(I) The outer peripheral portion of the material to be processed, which is not a product, is pressed and fixed by a holder onto an outer die arranged outside the main die that comes into contact with a portion to be processed in the material to be processed. Punch with a punch,
(Ii) With the punch-side surface of the outer holder abutting the punching end surface of the processed material and restraining the processed material, the punch and the main die punch out the outer peripheral part of the processed material that is not a product,
(Iii) The punched material is punched, that is, the punch side surface of the outer holder is in contact with the punched end surface of the punched material, and the punched material is pushed up in a restrained state, and the other punched end surface of the punched material is It is characterized in that it is rubbed against the sheared surface of the processed material.

The embodiment of the method of the present invention capable of forming a sheared surface having excellent surface properties even when shearing a high-strength workpiece has been described above.

Here, the effect of improving the surface property of the sheared surface of the processed material by rubbing the end surface of the blank and the sheared surface of the processed material is that the distance d (mm) between the die and the punch is A range in which the angle of the fracture surface on the machined surface is 3° or more with respect to the punch direction (the fracture surface and the shoulder surface of the blank contact each other at a required angle, and a plastic deformation of compression is applied to the surface layer of the sheared surface of the machined material. It will be explained that the setting is improved in the range that can be added).

FIG. 27 schematically shows the basic concept of the method of the present invention. FIG. 27(a) schematically shows the basic concept of shearing, and FIG. 27(b) schematically shows the basic concept of rubbing.

As shown in FIG. 27( a ), a work piece having a thickness t (mm), which is pressed and fixed by a holder 15 on the die 12, is punched with a punch 17 having a space d with a restraining force P added. Shearing is performed in cooperation with the die 12. As shown in FIG. 2, the sheared surface of the processed material 14a is generally composed of a sag 4, a shear surface 5, a fracture surface 6, and a burr 7.

The shape of the end surface of the punched material 19 has a point-symmetrical relationship with the shape of the sheared surface of the processed material 14a, and is similarly composed of a sag, a sheared surface, a fractured surface, and a burr. In FIG. 27A and FIG. 27B, the shape of the sheared surface of the processed material 14a and the shape of the sheared surface of the processed material 14a and The shape of the end surface of the blank 19 is schematically shown by a sheared surface and a cut surface.

The fracture angle of the fracture surface 6 of the processed material 14a (angle with respect to the punch direction) and the fracture angle of the fracture surface 6a of the punched material 19 (angle with respect to the punch direction) were the same.

During the shearing process of the work material, the restraining force P on the work material is (a) the machine frame (see FIGS. 3 to 6), (b) the projection provided on one or both of the punch and the back pressure pin (FIG. 7 to 14), or (c) a die, a back pressure pin, or a holder (see FIGS. 15 to 25) for sandwiching the punched material that has been previously punched out.

At the shearing stage, in order to form a sheared surface having good surface properties on the processed material (and the blank), the shape of the cutting edge 17z of the punch 17, the shape of the cutting edge 12z of the die 12, and the punch 17 are used. It is important to properly set the distance d (mm) between the die 12 and the die 12.

The shape of the blade tip 17z of the punch 17 and the shape of the blade tip 12z of the die 12 preferably have a small radius of curvature R (mm) from the viewpoint of obtaining a sheared surface having a high degree of verticality. If R is small, the sag on the sheared surface will be small, the ratio of the sheared surface will increase, and the perpendicularity of the sheared surface will increase, so that the sheared surface of the processed material and the end surface of the blank will be rubbed together. The effect of improving the surface properties is improved.

As shown in FIG. 27( b ), the sheared surface of the processed material and the end surface of the punched material are rubbed with each other by punching with the punch 17 and the back pressure pin 13 while maintaining the constraint force P against the punched material 19. The material 19 is pushed up. The shearing surface 21 of the processed material 14a and the end surface 20 of the blank 19 are rubbed against each other so that the fracture surface 6a of the blank 19 abuts the fracture surface 6 of the processed material 14a, and the blank 19 is brought into a restrained state. Therefore, compression plastic working can be sufficiently applied to the surface layer of the sheared surface 21 of the worked material 14a.

Rubbing of the sheared surface 21 of the processed material 14a and the end surface 20 of the blank 19 may be stopped while pushing up the blank 19 (during rubbing), or by rubbing the sheared surface of the processed material with burrs. If the phenomenon does not occur, the blank may be pushed up onto the processed material. If burrs are present on the sheared surface of the processed material, the fatigue characteristics and hydrogen embrittlement resistance of the processed material deteriorate, so it is necessary to avoid the occurrence of burrs as much as possible.

Next, a mechanism will be described in which the surface layer of the sheared surface of the processed material is subjected to plastic working by compression by rubbing the end surface of the blank and the sheared surface of the processed material. FIG. 28 schematically shows a mechanism for rubbing the end surface of the blank and the sheared surface of the worked material. FIG. 28(a) shows an abutting cross section of the fracture surface at the start of rubbing, and FIG. 28(b) shows the plastic working area at the end of rubbing.

As shown in FIG. 28( a ), the back pressure pin 13 restrains the punched material 19 having the length 1 of the sheared surface in the punch direction and the fracture angle θ (angle with respect to the punched direction) of the fractured surface 6 a with respect to the punched material 19. The force P is maintained and pushed up to bring the fracture surface 6a of the blank 19 into contact with the fracture surface 6 of the processed material 14a. The fracture angle of the fracture surface 6 of the processed material 14a is substantially the same as the fracture angle (angle with respect to the punch direction) of the fracture surface 6a of the punched material 19. Although θ is preferably 3° or more, this point will be described later.

When the restraint force P is maintained and the blank 19 is further pushed up and the end surface of the blank 19 and the sheared surface of the blank 14a are rubbed against each other, the fracture surface collision is approximately the same as the distance d between the punch and the die. In the contact area, a material overlapping area occurs, and a compressive plastic deformation occurs in the area. Then, when the punched material 19 is pushed up to the position of the processed material 14a, as shown in FIG. 28(b), the plastic deformation region Z of compression is generated in the fracture surface collision region having a width substantially the same as the distance d between the punch and the die. It is formed.

As a result, compressive plastic deformation is applied to the surface layer of the sheared surface of the processed material 14a, the tensile residual stress in the sheared surface is reduced, and the surface properties are significantly improved. That is, according to the method of the present invention, the surface property of the sheared surface of the processed material is remarkably improved by rubbing the end surface (sheared surface) of the processed material with the sheared surface of the processed material under the condition of restraining the cut material. Can be increased to This is a characteristic of the method of the present invention.

The larger the material overlap region, the wider the compression plastic deformation region Z (see FIG. 28B), and the larger the amount of residual stress reduction, but the smaller the material overlap region (that is, the compression plastic deformation region Z). Even if it is narrow), the end surface of the blank and the sheared surface of the blank are rubbed together while the blank is restrained, so it is possible to apply compressive plastic deformation to the surface layer of the sheared surface of the blank. In addition, the effect of improving the surface quality can be obtained.

As shown in FIG. 2, the sheared surface of the processed material is usually composed of a sag 4, a sheared surface 5, a fractured surface 6 and a burr 7. However, the shape of the sheared surface, especially the burr 7 The shape (breaking angle θ with respect to the punch direction) greatly changes depending on the distance d (mm) between the die and the punch, and as described with reference to FIG. 28, at the distance d, the width of the plastic deformation region Z of compression, and Since the mode of plastic deformation of compression is substantially determined, the setting of the distance d between the punch 17 and the die 12 is important for improving the surface property of the sheared surface of the processed material.

When the distance d between the punch 17 and the die 12 is small, the sagging on the sheared surface is usually small, the ratio of the sheared surface is increased, and the perpendicularity of the sheared surface is increased. The distance d is a thickness t (mm) of the material to be processed, and in consideration of strength as appropriate, within a range in which a required verticality can be secured, and the fracture surface of the sheared surface and the shoulder surface of the blank are It is set within a range in which the fracture angle of the fracture surface can be secured by which the plastic deformation of compression can be applied to the surface layer of the sheared surface of the processed material by the collision.

The present inventors set the distance d (mm) between the die and the punch in relation to the thickness t (mm) of the material to be processed (d=ta·a [a: coefficient]), and shear the processed material. The perpendicularity of the machined surface and the fracture angle (fracture surface angle) θ of the fracture surface were investigated.

According to the result, the space d (mm) between the punch 17 and the die 12 ensures the required verticality, and the shearing of the processed material is caused by the contact between the fracture surface of the sheared surface and the shoulder surface of the blank. T(mm)×0.50 or less is preferable in that it is possible to secure a fracture surface angle capable of applying compressive plastic deformation to the surface layer of the processed surface, preferably 3° or more. When the distance d (mm) exceeds t×0.50, a large amount of sagging occurs on the sheared surface of the processed material, and the ductile fracture crack forming the fracture surface does not face the die shoulder direction. As the size becomes smaller, the surface quality of the sheared surface deteriorates.

When the perpendicularity of the sheared surface of the processed material increases, the fracture surface angle θ of the sheared surface usually becomes smaller, but the fracture surface angle at which the plastic deformation of compression can be applied to the surface layer of the sheared surface of the processed material The distance d between the punch 17 and the die 12 may be t×0.30 or less, or t×0.10 or less as long as it is possible to secure at least 3°.

FIG. 29 shows an example of a vertical sectional form of the sheared surface of the processed material. FIG. 29(a) shows a vertical sectional form of a sheared surface in the case where the distance d (mm) between the die and the punch is the thickness t (mm)×0.40 of the work material, and FIG. The vertical cross-sectional form of the sheared surface is shown in Fig. 3 when the distance d (mm) between the die and the punch is the thickness t (mm) x 0.20 of the workpiece.

When the distance d (mm) between the die and the punch is the thickness t (mm) x 0.40 of the workpiece (see FIG. 9A), the fracture does not go to the shoulder of the die and the workpiece is processed. Although the sheared surface is formed by advancing in the plate thickness direction of the material, since the perpendicularity of the sheared surface is high, it is possible to sufficiently expect improvement in surface quality by rubbing with the end surface of the blank.

When the distance d (mm) between the die and the punch is the thickness t (mm) of the work material x 0.20 (see Fig. 9(b)), the fracture progresses toward the shoulder of the die, Since the sheared surface having a high degree of verticality is formed, it is possible to sufficiently expect the improvement of the surface properties by rubbing with the end surface of the blank.

FIG. 30 shows an example of a vertical sectional form of a sheared surface of another processed material. FIG. 30(a) shows a vertical cross-sectional form of the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm)×0.05 of the material to be processed, and FIG. The vertical cross-sectional form of the sheared surface is shown in Fig. 3 when the distance d (mm) between the die and the punch is the thickness t (mm) x 0.10.

The inventors of the present invention restrain the blank material on the sheared surface shown in FIGS. 29 and 30, rub the end faces of the blank material, and measure the residual stress on the sheared surface before and after the rubbing of the blank surface. did.

FIG. 31 shows measurement positions of residual stress on the sheared surface. As shown in FIG. 31, on the sheared surface, there are three points along the plate thickness direction of the processed material 14a, that is, a burr side position (s3), a plate thickness center position (s2), and a sag side position (s1). Was irradiated with X-rays having a spot diameter of 500 μm, and the residual stress at these positions was measured using the sin ² Ψ method.

32 to 36 show residual stress distributions on the sheared surface before and after rubbing the end faces of the blank. FIG. 32 shows the residual stress distribution on the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm)×0.05 (CL 5%) of the workpiece. FIG. 33 shows the residual stress distribution on the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm)×0.10 (CL 10%) of the work material.

FIG. 34 shows the residual stress distribution on the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm)×0.20 (CL20%) of the work material. FIG. 35 shows the residual stress distribution on the sheared surface when the distance d (mm) between the die and the punch is the thickness t (mm)×0.40 (CL 40%) of the workpiece.

From FIGS. 33 and 34, the case where the distance d (mm) between the die and the punch is the thickness t (mm)×0.10 of the work piece and the thickness t (mm)×0.20 of the work piece. In the case of, when the sheared surface of the processed material and the end surface of the blank are rubbed, the residual stress in the thickness direction is greatly reduced at the burr side and the center of the thickness, and the residual stress distribution on the sheared surface of the processed material becomes uniform. I understand.

From FIG. 35, when the distance d (mm) between the die and the punch is the thickness t (mm)×0.40 of the material to be processed, burrs were generated in the lower part of the sheared surface of the material to be processed, but the material was in a restrained state. It is understood that the residual stress is reduced by rubbing with the end surface of the blank and the residual stress distribution on the sheared surface becomes uniform.

In particular, when the distance d (mm) between the die and the punch is the thickness t (mm) x 0.20 of the material to be processed (see Fig. 32 ), the residual stress on the burr side and the center of the plate thickness greatly decreases, The residual stress distribution is almost uniform on the compression side.

When the distance d (mm) between the die and the punch is the thickness t (mm) of the work material x 0.05 (see Fig. 32 ), a secondary shear cross section occurred on the sheared surface of the work material, The residual stress is reduced by rubbing the end surface of the blank material in the state with the sheared surface of the processed material, and the residual stress distribution on the sheared surface is made uniform.

The breaking angle θ of the fracture surface on the sheared surface of the processed material changes depending on the distance d (mm) between the die and the punch. Due to this change, the surface property improving effect on the sheared surface of the processed material due to the rubbing of the end surface of the punched material in the restrained state and the sheared surface of the processed material changes. And the residual stress reduction amount were investigated.

FIG. 36 shows the fracture surface angle (breaking angle) and the residual stress reduction when the distance d (mm) between the die and the punch is set within the range of the thickness t (mm) of the workpiece to be 0.01 to 0.2. The relationship of quantity is shown. From FIG. 36, it is understood that when the fracture surface angle exceeds 3° with respect to the punch advancing direction, the residual stress reduction amount greatly increases.

That is, when the distance d (mm) between the die and the punch is set so that the breaking angle of the fracture surface on the sheared surface of the processed material is 3° or more with respect to the punch direction, the surface property on the sheared surface of the processed material is set. It was found that the improvement effect can be obtained more significantly.

As described above, the method of the present invention has a basic idea of using a blank as a tool for adjusting a sheared surface of a workpiece, and after shearing, restrains the blank against the workpiece. However, the surface property of the sheared surface of the processed material is remarkably enhanced by rubbing the end surface of the punched material in the restrained state and the sheared surface of the processed material.

Next, an example of the present invention will be described. The condition in the example is one condition example adopted for confirming the feasibility and effect of the present invention, and the present invention is based on this one condition example. It is not limited. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

(Example 1)
The outer peripheral portion of a 1200 MPa class steel plate (workpiece) having a plate thickness of 1.6 mm and a size of 50 mm×50 mm was punched with a punch having an inner diameter of 30 mm. The distance d (mm) between the die and the punch was set to the plate thickness t (mm)×0.20 of the steel plate (workpiece). After punching, restrain the punched material against the processed material, push it up to the position of the steel plate (worked material) in the state of being punched, and rub the end surface of the punched material and the sheared surface of the steel plate (worked material) It was

After the rubbing, the average residual stress of the sheared surface of the steel sheet (working material) was measured and compared with the average residual stress of the sheared surface before rubbing. The results are shown in Table 1.

It can be seen from Table 1 that the residual stress on the sheared surface of the steel sheet (working material) is reduced by the rubbing.

The processed material was immersed in a 1 to 100 g/L ammonium thiocyanate solution for 72 hours, and the hydrogen embrittlement resistance of the sheared surface before and after rubbing was investigated. The results are shown in Table 2.

As shown in Table 2, by rubbing the end surface of the blank and the sheared surface of the processed material, the hydrogen embrittlement resistance of the sheared surface is greatly improved.

(Example 2)
The outer peripheral portion of a 1200 MPa class steel plate (workpiece) having a plate thickness of 1.6 mm and a size of 50 mm×50 mm was punched with a punch having an inner diameter of 30 mm. The distance d (mm) between the die and the punch is set to the plate thickness t (mm) of the steel plate (workpiece) x 0.10, the plate thickness t (mm) of the steel plate (workpiece) x 0.20, and the steel plate. (Working material) punched out with a plate thickness t (mm) x 0.40, after punching, the punched material is restrained against the worked material and pushed up to the position of the steel sheet (worked material) in the state of being punched out Then, the end face of the blank and the sheared surface of the steel plate (working material) were rubbed together.

The residual stress at the center of the plate thickness on the sheared surface of the processed material (steel plate) after rubbing was measured and compared with the residual stress at the center of the plate thickness on the sheared surface before rubbing. The results are shown in Table 3.

It can be seen from Table 3 that the residual stress on the sheared surface of the processed material is greatly reduced by the rubbing.

The processed steel sheet after the rubbing was immersed in a 1 to 100 g/L ammonium thiocyanate solution for 72 hours to investigate the hydrogen embrittlement resistance. The results are shown in Table 4.

As shown in Table 4, by rubbing the end surface of the blank and the sheared surface of the worked material, the hydrogen embrittlement resistance of the sheared surface is greatly improved.

(Example 3)
With respect to the processed material obtained in Example 1, a flat plate bending fatigue test was performed in a room temperature atmosphere with a stress ratio of -1 and a frequency of 25 Hz, and fatigue characteristics (σa: fatigue limit) were measured. FIG. 37 shows the fatigue characteristics measured by the flat plate bending fatigue test. From FIG. 37, it is understood that when the end surface of the blank and the sheared surface of the processed material are rubbed together, the tensile residual stress on the sheared surface is reduced and the fatigue characteristics are improved.

As described above, according to the present invention, it is possible to obtain a processed material having a sheared surface having excellent surface properties with high productivity and at low cost even when the strength of the processed material is high. Therefore, the present invention is highly applicable in the metal member manufacturing industry.

1 Work Material 2 Punch 2a Downward 3 Die 4 Dull 5, 5a Shear Surface 6, 6a Fracture Surface 7 Burr 8a Upper Surface 8b Lower Surface 9 Shear Processed Surface 10 Work Material 11 Elastic Member 12, 12a Die 12z Die Edge 13 , 13a Back pressure pin 13b Connection back pressure pin 14 Work piece 14a Work piece 14b Outer part of work piece 14ba Outer part of outer circumference part of work piece 14bb Inner part of outer circumference part of work piece 15, 15a Holder 16 Elastic Member 17, 17a Punch 17b Connection punch 17z Punch blade edge 18 Machine frame 19 Cutting material 19a Cutting space 20 End surface of cutting material 21 Shearing surface 22 Protrusion d Distance between punch and die t Thickness of work material s1, s2, s3 Position of residual stress measurement l Length of shear plane P Restraint force Z Plastic deformation area θ Break angle

Claims (13)

In the shearing method of punching out the non-product part of the workpiece placed on the die with a punch,
(I) After punching, the punched material (non-product portion) is constrained by a punch punched from the punched material and a back pressure pin to oppose the processed material (product portion),
(Ii) The end face of the blank is rubbed against the sheared face of the workpiece in the above-mentioned opposing state , and
A shearing method, wherein the distance between the die and the punch is set within a range in which the angle of the fracture surface of the processed material is 3° or more with respect to the punch traveling direction . The shearing method according to claim 1, wherein one or both surfaces of the punch and the back pressure pin for restraining the punched material have a projection for restraining the punched material. The shearing method according to claim 2, wherein a closest distance between the protrusion and the die on which the processed material is placed is 2t (t (mm): thickness of the processed material) or less. The punch and the back pressure pin for restraining the punched material are placed, and the pair of punch and the back pressure pin having the projection for restraining the punched material on one or both surfaces of the punch and the back pressure pin are placed on the processed material. The method for shearing according to claim 1, wherein the die is provided integrally or separately on the opposite side of the die. The distance between the pair of punches and the back pressure pins having the projections for restraining the blank and the die for mounting the workpiece is 2t (t (mm): thickness of the workpiece) or less. The shearing method according to claim 4. The projection is in a form extends continuously (a), or, (b) point-shaped, arcuate, or any of claims 2-5, characterized in that present in the form of continuous and intermittent in dashed line form The shearing method according to item 1. Shearing method according to any one of claims 2-6, wherein the height of the projections is 10 to 1000 [mu] m. 8. The shearing method according to claim 2, wherein the width of the protrusion is 10 to 1000 μm. In the shearing method of punching out the non-product part of the workpiece placed on the die with a punch,
(I-1) After punching, place the side of the die on which the blank (non-product part) is placed, the side of the holder that fixes the blank (non-product part) on the die, or the blank (non-product part). On the side of the punched punch, in the restrained state of restraining the work material, further punching the non-product part of the work material,
(I-2) After the punching, in the restrained state, the punched material (non-product portion) is restrained by the punch and the back pressure pin punched out of the punched material to oppose the processed material (product portion),
(Ii) The end face of the blank is rubbed against the sheared face of the workpiece in the above-mentioned opposing state , and
A shearing method, wherein the distance between the die and the punch is set within a range in which the angle of the fracture surface of the processed material is 3° or more with respect to the punch traveling direction . A side surface of a die on which the punched material (non-product portion) is placed, a side surface of a holder that fixes the punched material (non-product portion) on the die, or a side surface of a punch punched with the punched material (non-product portion), 10. The shearing method according to claim 9, wherein the distance from the die on which the processed material is placed is 2t (t (mm): thickness of the processed material) or less. The shearing method according to any one of claims 1 to 11 , wherein the rubbing between the end surface of the blank and the sheared surface of the processed material is stopped midway. The workpiece is sheared method according to any one of claims 1 to 11, characterized in that a higher tensile strength 980MPa of the steel sheet. The workpiece is sheared method according to any one of claims 1 to 11, that wherein a laminated steel containing more than tensile strength 980MPa of the steel sheet.