JP7335481B2 - Shearing method and shearing device - Google Patents

Description

The present invention relates to a shearing method and a shearing device.

Shearing is performed for cutting, punching, punching, shaving, trimming, and the like of metal members in the manufacture of metal parts used for automobiles, railroad vehicles, building materials, ships, home appliances, and the like. In the shearing process, the workpiece is sandwiched between an upper blade and a lower blade having corresponding shapes, plastically deformed, and finally broken. Shearing can cut the workpiece into various shapes. For example, Patent Literature 1 describes a press that punches out a workpiece into a substantially square shape.

On the other hand, in Non-Patent Document 1, in punching a rectangular contour shape with rounded corners, the corners of the punch are rounded in the axial direction so that the shear separation surface is formed at each of the straight side and the corner. Techniques are described for mitigating differences in the amount of "who" that occurs. According to Non-Patent Document 1, when a conventional flat punch is used, the amount of sag at the corner is smaller than that at the straight side, but when a punch with rounded corners in the axial direction is used, the corner is The difference in droop amount between the straight side portion and the straight side portion is reduced.

JP 2011-136348 A

Kozo Kato, 4 others, ``Fundamental study on control of sagging amount in punching,'' Proc.

Here, generally speaking, a smaller droop amount is advantageous because the cut surface becomes vertical and the accuracy of positioning based on, for example, the cutting line is improved. In the technique described in Non-Patent Document 1, the difference in the droop amount between the corner portion and the straight side portion is reduced by increasing the droop amount of the corner portion to the same extent as the droop amount of the straight side portion. Therefore, the amount of droop at the corners is rather large, and the advantage of the small amount of droop as described above cannot be obtained.

Therefore, the present invention provides a new and improved shearing method and shearing device capable of reducing the amount of sagging at the corners when punching a workpiece into a shape having corners by shearing. One of the purposes is to

According to one aspect of the present invention, the corner is formed by moving the first blade relative to the second blade in the thickness direction of the workpiece, the first blade and the second blade being provided. A shearing device capable of cutting a workpiece along a cutting line including a section, wherein a first blade defines a first section along the cutting line and corresponding to a corner of the cutting line. and a non-protruding portion formed in a second section other than the first section defined along the cutting line, when the first blade faces the workpiece A shearing device is provided in which the protrusions are located closer to the workpiece than the non-protrusions.
According to the above configuration, the protrusion is formed in the first section of the upper blade corresponding to the corner of the cutting line, and the non-protrusion is formed in the second section other than the upper blade. Influence on the end shape after processing due to the breakage at the corner of the workpiece occurring earlier than the straight portion or at the same time as the straight portion, and the breakage at the corner being delayed. can be reduced.

In the shearing device, the first section may coincide with or encompass the corner.

In the shearing device, the first section may correspond to part of the corner.

In the shearing device, the cutting line may include a corner portion and a straight portion, or may include a corner portion and a curved portion having a larger radius of curvature than the corner portion.

Furthermore, a shearing method characterized by shearing a workpiece using any one of the shearing apparatuses described above can reduce the drooping amount of the sheared portion of the workpiece after shearing.

In addition, when the work material is a high-strength steel sheet having a tensile strength of 590 MPa or more, it is possible to effectively reduce the sagging amount of the sheared portion of the work material after shearing, which is useful in terms of industrial production.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, when a workpiece is punched into a shape having corners by shearing, the amount of droop at the corners can be reduced. In particular, when a high-strength steel plate having a tensile strength of 590 MPa or more is used as the work material, the droop amount of the sheared portion of the work material after shearing can be effectively reduced, which is useful in terms of industrial production.

1 is a longitudinal sectional view of a shearing device according to one embodiment of the present invention; FIG. 2 is a cross-sectional view of the shearing device shown in FIG. 1; FIG. It is a figure for demonstrating the relationship between the shape of the cutting line of a to-be-processed material, and the edge part shape after a process. 1. It is a figure which shows the example of the shape of the protrusion part of the shearing apparatus shown by FIG. 1. It is a figure which shows the example of the shape of the protrusion part of the shearing apparatus shown by FIG. 1. It is a figure which shows the example of the shape of the protrusion part of the shearing apparatus shown by FIG. It is a figure for demonstrating the shape of the punch in one Example of this invention. 4 is a graph showing droop ratios in Examples and Comparative Examples at corner portions and straight portions, respectively.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

FIG. 1 is a vertical cross-sectional view of a shearing device according to one embodiment of the present invention. 2 is a cross-sectional view of the shearing device shown in FIG. 1; FIG. Here, the longitudinal section shown in FIG. 1 corresponds to the II line in FIG. 2, and the transverse section shown in FIG. 2 corresponds to the II-II line in FIG. As shown in FIGS. 1 and 2, shearing device 1 includes punch 2 , die 3 and holder 4 . The configuration of each unit will be further described below.

As shown in FIG. 1, in the shearing device 1, the punch 2 is formed with an upper blade 21 as a first blade, and the die 3 is formed with a lower blade 31 as a second blade. The punch 2 is driven by an electric motor or hydraulic mechanism (not shown), and moves in the thickness direction of the workpiece W, that is, in the vertical direction in the figure. At this time, the upper blade 21 formed on the punch 2 moves in the thickness direction of the workpiece W relative to the lower blade 31 . In this manner, the shearing device 1 can cut the workpiece W along the cutting line including the corners, as will be described later. The holder 4 abuts the workpiece W from above in a region surrounding the punch 2, and holds the workpiece W between itself and the die 3, thereby stabilizing the position of the workpiece W during cutting.

As shown in FIG. 2, both the upper blade 21 formed on the punch 2 and the lower blade 31 formed on the die 3 are rectangular with rounded corners. More specifically, the upper blade 21 has a shape including four convex corners corresponding to the inside of the rounded rectangle, and the lower blade 31 has four concave corners corresponding to the outside of the rounded rectangle. It is a shape that contains In this embodiment, a projecting portion 21A is formed at the convex corner of the upper blade 21 . Other portions of the upper blade 21 are formed with non-projecting portions 21B. As shown in FIG. 1, the protruding portion 21A is a portion of the upper blade 21 that protrudes downward, and when the upper blade 21 faces the workpiece W, the protruding portion 21A is covered more than the non-protruding portion 21B. Situated proximate to the workpiece W.

By including the projecting portion 21A and the non-projecting portion 21B in the upper blade 21, in the present embodiment, the end shape of the workpiece W at the corner of the cutting line after processing can be improved. This point will be further explained below.

FIG. 3 is a diagram for explaining the relationship between the shape of the cutting line of the workpiece and the shape of the end portion after processing. The present inventors used a flat punch different from the punch 2 according to the present embodiment described above, that is, a punch in which the protruding portion 21A and the non-protruding portion 21B are not formed on the upper blade. It was punched out and the edge shape was observed. As a result, the corner portion P _A of the cutting line P shown in FIG. 3, that is, the portion where the cutting line P has a curvature, is compared to the straight portion P _B of the cutting line P, that is, the portion where the cutting line P does not have a curvature. A small but moderate amount of whooping occurred.

Here, the inventors of the present invention further observed the end shape of the workpiece W at the corner portion _PA and the straight portion _PB , and as a result, the following findings were obtained. When the upper surface of the workpiece W is used as a reference, the distances to the starting position of the fracture surface are different between the corner portion P _A and the straight portion P _B . Specifically, the distance from the upper surface of the workpiece W to the starting position of the fracture surface is longer at the corner _PA . This is because when the workpiece W is cut along the cutting line P, the workpiece W breaks first at the straight part _PB and breaks at the corner part _PA later. it is conceivable that.

In order to reduce the droop amount of the corners _PA in the end shape of the workpiece W after processing, it is desirable that the workpiece W be broken along the cutting line P while being constrained from both sides. . However, according to the above findings, the straight portion _PB is broken while being constrained from both sides along the cutting line P, whereas when the corner portion _PA is broken, the straight portion _PB is already broken. Therefore, the corner portion P _A is broken off with the side adjacent to the straight portion P _B being unconstrained. It is considered that if the corner portion _PA is broken along the cutting line P while being constrained from both sides, the droop amount can be further reduced.

Therefore, in the shearing device 1 according to the present embodiment, by forming the projecting portion 21A and the non-projecting portion 21B on the upper blade 21 as described above, the fracture at the corner portion _PA of the workpiece W can be straightened. It is generated prior to the portion _PB or at the same time as the straight portion _PB . Specifically, for example, the relative height of the projecting portion 21A with respect to the non-projecting portion 21B is defined as the distance from the upper surface of the workpiece W to the start position of the fractured surface at each of the corner portion _PA and the straight portion _PB of the cutting line P. If the distance is greater than or equal to the difference in distance, the breakage at the corner P _A of the workpiece W can occur prior to the straight portion _PB or at the same time as the straight portion _PB .

4A to 4C are diagrams showing examples of shapes of protrusions of the shearing device shown in FIG. 1. FIG. As described above, the protrusion 21A is formed at the convex corner of the upper blade 21 . Here, the convex corner corresponds to the corner P _A of the cutting line P, that is, the portion where the cutting line P has a curvature. This relationship will be described below using a first section S _A and a second section S _B defined along the cutting line P on the upper blade 21 . The first section S _A is a section corresponding to the corner P _A of the cutting line P, and the second section S _B is a section other than the first section. A projecting portion 21A is formed on the upper blade 21 in the first section _SA , and a non-projecting portion 21B is formed on the upper blade 21 in the second section _SB . As will be described below, the first section S _A corresponds to the corner P _A , that is, the portion where the cutting line P has a curvature, but does not necessarily coincide with the corner P _A .

In the example shown in FIG. 4A, the first section S _A coincides with the corner P _A. On the other hand, in the example shown in FIG. 4B, the first section S _A includes the corner portion P _A and spans part of the straight portion _PB . In the straight part _PB , since the workpiece W is almost simultaneously broken in a section of a certain length of the cutting line P, the first section S _A extends over a part of the straight part _PB , and this part is a straight line. Even in the portion _PB , there is no problem in that the workpiece W is fractured first. On the other hand, in the example shown in FIG. 4C, the first section S _A corresponds to part of the corner P _A. That is, in this example, the second section S _B spans not only the straight portion P _B but also a part of the corner P _A , and the workpiece W breaks at this portion slower than the first section S _A. Become. However, for example, when the corner portion _PA is used as a reference for positioning, it is particularly important to reduce the amount of sag at the central portion of the corner portion _PA . If this portion is included in section _SA , the effect of reducing the droop amount can be expected.

Also, in the example shown in FIG. 4A, the planar shape of the protrusion 21A formed in the first section _SA is a sector, but as in the example shown in FIG. 4B, the shape includes an arc and a chord. There may be one, or it may be trapezoidal, as in the example shown in FIG. 4C, or rectangular. As described above, the projecting portion 21A is provided in order not to delay the breakage of the workpiece W at the corner portion _PA . Although the shape of the portion is defined as above, the planar shape that does not directly affect the cutting of the workpiece W, that is, the shape of the end surface of the punch 2 can be arbitrarily shaped. It is possible. Also, the surface of the protruding portion 21A on the end surface side of the punch 2 may have any surface shape such as a flat surface, a curved surface, or an uneven surface.

An embodiment of the present invention has been described above. In this embodiment, a protruding portion 21A is formed in the first section S _A of the upper blade 21 corresponding to the corner P _A of the cutting line P, and a non-protruding portion 21B is formed in the other second section S _B. By forming, during the shearing process, the breakage at the corner P _A of the workpiece W is caused prior to the straight portion _PB or at the same time as the straight portion _PB , and the break at the corner P _A is delayed. It is possible to reduce the influence on the shape of the end portion after processing, specifically, to reduce the droop amount at the corner portion _PA .

In the above example, the cutting line P has a rectangular shape with rounded corners, but the shape of the cutting line P is not limited to a rectangle as long as it includes corners. For example, the shearing device 1 may punch the workpiece W along a cutting line P having a shape such as a triangle, a pentagon, a hexagon, or an octagon. Further, the cutting of the workpiece W by the shearing device 1 is not limited to punching, and the cutting line P does not necessarily have to be a closed shape. For example, the shearing device 1 may bisect the workpiece W along a cutting line P having a shape including corners.

In the above example, the cutting line P includes the corner portion P _A and the straight portion P _B , and the corner portion P _A is a portion where the cutting line P has a curvature. The corner portion _PA may be a portion where the radius of curvature of the cutting line P is smaller than that of other portions. In other words, the portion of the cutting line P other than the corner _PA may not necessarily be the straight portion _PB , and may be a curved portion having a larger radius of curvature than the corner _PA . This embodiment is applicable to a variety of work pieces W, in particular plates such as steel or aluminum alloys, for example.

In the above example, the projecting portion 21A was described as a stepped portion when viewed along the cutting line P, but the projecting portion 21A is a mound-shaped portion when viewed along the cutting line P. may be Alternatively, a transition portion may be provided between the projecting portion 21A and the non-projecting portion 21B. The transition can be, for example, stepped or sloped when viewed along the cutting line P. In the above example, the non-projecting portion 21B formed on the upper blade 21 was a uniform portion, but the non-projecting portion 21B may include a projecting portion within a range not exceeding the projecting portion 21A. As a result, the non-protruding portion 21B may have unevenness within a range not exceeding the protruding portion 21A when viewed along the cutting line P. Further, for example, the non-protruding portion 21B corresponding to one of the four linear portions _PB formed when the cutting line P is in the shape of a rounded rectangle is relatively small with respect to the other non-protruding portions 21B. By protruding inward, the punched piece of the workpiece W can be easily recovered. In addition, when the upper blade 21 includes a plurality of projecting portions 21A, the amount of projection, that is, the amount of projection based on the adjacent non-projecting portion 21B, depends on the radius of curvature of the cutting line P corresponding to each projecting portion 21A. The heights of the protruding portions 21A may be different from each other, and the planar shapes of the protruding portions 21A may be different from each other.

Next, examples of the present invention will be described. In this embodiment, the work material W is a steel plate having a tensile strength of 590 MPa class and a thickness of 1.6 mm. Shearing is punching along the cutting line P of a rounded rectangle as shown in FIG. 20 mm). As shown in the side view and the bottom view of FIG. 5, the punch 2 used had projections 21A formed in sections substantially coinciding with the convex corners of the upper blade 21 . The radius of curvature R of the corner portion is 1 mm, and the protrusion amount ΔH of the protruding portion 21A relative to the non-protruding portion 21B is 0.3 mm. An example using the punch 2 as described above and a comparative example (ΔH=0 mm) in which the protrusion 21A was not formed on the upper blade 21 of the punch 2 were subjected to shearing. The amount of droop was measured at the corner portion (corner portion P _A shown in FIG. 3) and the straight portion (straight portion P _B shown in FIG. 3).

FIG. 6 is a graph showing the droop ratio, that is, the ratio of the droop amount to the plate thickness in each of the corner portions and the straight portions in the example and the comparative example. Referring to the graph of FIG. 6, while the droop ratios of the example and the comparative example are almost the same at the straight line portion, the droop ratio of the example is reduced to about half that of the comparative example at the corner portions. From this result, it can be said that the drooping amount of the corner portion could be significantly reduced in the present example as compared with the comparative example.

The examples described above demonstrate that the present invention is effective in reducing the amount of sagging at the corners of a workpiece that has been punched into a shape having corners by shearing.

Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1... Shearing apparatus, 2... Punch, 3... Die, 4... Holder, 21... Upper blade, 21A... Protruding part, 21B... Non-protruding part, 31... Lower blade, P... Cutting line, W... Work material.

Claims (9)

Cutting including a curved corner by moving the first blade relative to the second blade in the thickness direction of the workpiece, comprising a first blade and a second blade A shearing device capable of cutting the workpiece along a line,
The first blade includes a projection formed in a first section defined along the cutting line and corresponding to a corner of the cutting line, and the first section defined along the cutting line. and a non-protruding portion formed in the second section other than
When the first blade faces the workpiece, the projecting portion is positioned closer to the workpiece than the non-projecting portion , and
The shearing device, wherein the projection is a stepped or rounded portion when viewed along the cutting line . 2. The shearing device according to claim 1, wherein the protruding portion and the non-protruding portion of the first blade are integrally formed. The protruding portion is a stepped portion when viewed along the cutting line, and the portion between the protruding portion and the non-protruding portion is stepped or stepped when viewed along the cutting line. 3. A shearing device according to claim 1 or claim 2, wherein a sloped transition is provided . 4. Any one of claims 1 to 3, wherein the first section coincides with a portion of the corner where the cutting line has a curvature, or includes a portion of the corner where the cutting line has a curvature. 1. A shearing device according to claim 1. The shearing device according to any one of claims 1 to 3, wherein the first section corresponds to a portion of the corner where the cutting line has a curvature. The second section includes a plurality of sections,
6. The method according to any one of claims 1 to 5, wherein one of the non-projecting portions formed in each of the plurality of sections protrudes relative to the other non-projecting portions. Shearing device. 7. The cutting line according to any one of claims 1 to 6, wherein the cutting line includes the corner portion and a straight portion, or includes the corner portion and a curved portion having a larger radius of curvature than the corner portion. shearing equipment. A shearing method comprising shearing a workpiece using the shearing device according to any one of claims 1 to 7. The shearing method according to claim 8, wherein the work material is a high-strength steel plate having a tensile strength of 590 MPa or more.

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