Die blades for shearing machines

Abstract

The present invention provides a die blade for a shearing machine that easily creates irregularities on the ends of curved or bent parts when shearing them. [Solution] A die blade 21 applied to a press machine 20 for shearing a steel plate placed on the upper surface of the die blade 21 to produce an outer panel part of a vehicle body having a curved or bent surface to the end, wherein the upper surface 21a of the die blade 21 has a recess 22 along the shear surface, and a bead corresponding to the shape of the recess 22 is formed at the end of the steel plate after shearing.

Description

Technical Field

[0001] The present disclosure relates to the shape of a die blade of a shearing device.

Background Art

[0002] A vehicle is configured by assembling complex-shaped vehicle body parts. Many of the vehicle body parts that form part of the outer shape of a vehicle, such as a bonnet, are press parts having curved surfaces or bent surfaces formed by steel sheets or the like. Among the vehicle body parts having such curved surfaces or bent surfaces, there are some in which the end portion is further folded back to form a flange.

[0003] For example, in Patent Document 1, the end portion of a curved press part (panel member) is bent to form a flange.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, for a press part that is curved or bent, when a flange is formed by bending including the curved or bent portion, stress acts on the flange and it may deform, and the portions around the flange may also deform. For example, in press parts of adjacent vehicle bodies such as a bonnet and a front fender of an automobile, when at least one of the end portions is deformed, even if it is a slight deformation, the butting surface may not match and the appearance of the vehicle may be deteriorated.

[0006] ​This disclosure was made to solve such problems and aims to provide a die blade for a shearing device that enables the easy manufacture of an outer panel member of a vehicle body having a curved or bent shape, and in which a flange is formed by bending including the curved or bent portion. [Means for solving the problem]

[0007] To achieve the above objective, the die blade of the present disclosure is a die blade applied to a shearing apparatus that shears a steel plate placed on the upper surface of the die blade to produce an outer panel part of a vehicle body having a curved or bent surface to the end, characterized in that the upper surface of the die blade has an uneven portion along the end face which is the shearing position, and after shearing the steel plate, an unevenness corresponding to the shape of the uneven portion is formed on the end of the steel plate. [Effects of the Invention]

[0008] According to the die blade of the shearing apparatus of this disclosure, by using the die blade in the shearing apparatus to shear a steel plate, for example, which is the material for the exterior panel of a vehicle body, irregularities are created along the shear surface of the steel plate. When an exterior panel part is manufactured by bending this irregularly shaped steel plate to form a flange, even if the steel plate is curved, the stress generated in the flange when forming the flange is relieved and absorbed, and deformation of the flange and the surrounding parts of the exterior panel part can be suppressed.

[0009] By using the die blades of the shearing apparatus of this disclosure, irregularities are created in the steel plate through shearing, thereby reducing the increase in the manufacturing process for the outer panel members and making it possible to easily manufacture outer panel members of the vehicle body that are curved, bent, and have flanges. [Brief explanation of the drawing]

[0010] [Figure 1] This is a top view of the hood of a vehicle having a press-formed part manufactured by a press machine according to one embodiment of the present disclosure. [Figure 2] This is a vertical cross-section of the hood before assembly. [Figure 3] This is a longitudinal cross-sectional view showing the assembly procedure for the hood. [Figure 4] This is an explanatory diagram of the procedure for forming the flange at the end of the outer component. [Figure 5] This is a top view showing the shape of the outer part before flange formation. [Figure 6] This is a longitudinal cross-sectional view of the end of the outer part before flange formation. [Figure 7] This is a front view of the end of the outer part before flange formation. [Figure 8] This is a perspective view showing the shape of the die blade of the press machine according to this embodiment. [Figure 9] This is an explanatory diagram showing the procedure for forming a bead on a pressed part using a press machine according to this embodiment. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a top view of a vehicle hood 1, which is a press-formed part manufactured by a press machine 20 according to one embodiment of the present disclosure. Figure 2 is a longitudinal cross-sectional view of the hood 1 before assembly, and is a cross-sectional view taken in the vehicle width direction. Figure 3 is a longitudinal cross-sectional view showing the assembly procedure of the hood 1. Note that Figure 2 is a drawing of the cross-section of part AA shown in Figure 1, with the outer part 2 on the lower side. Figure 3 is an enlarged view of the end of the hood.

[0012] As shown in Figure 1, the pressed parts for the vehicle body according to this disclosure are pressed parts formed by shearing and bending a steel plate with a press machine, such as the outer part 2 of the vehicle's hood 1. The hood 1 is a component that makes up the body of, for example, a plug-in hybrid vehicle (PHEV) or a hybrid vehicle (HEV). A PHEV refers to a hybrid vehicle that can be externally charged to or powered from a battery. A PHEV has a charging port (inlet) for inserting a charging cable into which power is supplied from an external charging facility, and an outlet for external power supply.

[0013] The bonnet 1 is formed by combining an outer part 2 which is a press part and an inner part 3 formed of a heat-resistant resin or the like. The outer part 2 is formed of a steel plate having a tensile strength of 270 [N / mm] or more and 340 [N / mm], such as cold-rolled steel sheet SPCC or hot-rolled mild steel sheet SPHC.

[0014] The outer part 2 is curved with respect to a flat plate extending in the vehicle longitudinal direction and vehicle width direction (left and right direction), and there are also portions bent at a slight angle. Before assembling the inner part 3, the outer part 2, as shown in FIG. 2, has its left and right ends bent at an angle of about 90 degrees to 105 degrees to form a flange 11.

[0015] As shown in FIG. 3, the bonnet 1 is manufactured by bending the flange 11 with a press or the like after fitting the inner part 3 inside the outer part 2 provided with the flange 11, and fixing it by sandwiching the left and right ends of the inner part 3. FIG. 4 is an explanatory view of the flange forming procedure at the end of the outer part 2. FIG. 5 is a top view showing the shape of the outer part 2 before flange formation. FIG. 6 is a longitudinal sectional view of the end of the outer part 2 before flange formation. FIG. 7 is a front view of the end face part of the outer part 2 before flange formation. Note that FIG. 6 is a sectional view of the B-B part described in FIG. 5. FIG. 7 is a view seen from C described in FIG. 5.

[0016] As shown in FIG. 4(A), the outer part 2 which is a press part has a bending line 8 (ridge line) inside the end face 7 of the plate-shaped steel sheet Ps having a curved part and a bent part (bending line 6), for example, about several centimeters inside the end face 7. As shown in FIG. 4(B), the end of the outer part 2 of the present embodiment is provided with a bead 10 (concave and convex) recessed in an elliptical hemispherical shape.

[0017] The bead 10 is formed by recessing the end of the outer part 2 in an elliptical hemispherical shape before flange formation. Then, as shown in Figure 4(C), the flange 11 is bent at approximately 90 degrees at the bending line 8 to form the outer part 2.

[0018] As shown in Figures 5-7, multiple beads 10 are arranged side by side at appropriately set intervals Di (for example, length 10 [mm]) on the end of the outer part 2 before flange formation, i.e., before the end is bent. The bead 10 is provided in an area that includes the end face 7 of the curved or bent portion of the outer part 2.

[0019] The bead 10 is formed by a recess 10a which is an arc formed by a part of an ellipsoid, and a flat portion 10b between adjacent recesses 10a. The recess 10a of the bead 10 is an ellipse with a width Dw (e.g., 8 mm) and a depth Dd (e.g., a depth of 0.6 mm) on the end face 7 of the outer part 2. The bead 10 may be semicircular when viewed from above the outer part 2, or it may be an ellipse with different lengths in the extension direction of the end face 7 and the direction perpendicular to it.

[0020] Furthermore, the boundary portion 10c between the recess 10a and the flat portion 10b of the bead 1 has a predetermined curvature R1 (for example, a radius of curvature of 0.1 mm) that is set as appropriate. Next, the method for forming the bead 10 will be explained using Figures 8 and 9. In the case of a pressed part equipped with a bead 10 at its end, such as the outer part 2 in this embodiment, the bead 10 is formed in conjunction with the shearing of the steel sheet Ps material by the press machine 20.

[0021] As shown in Figure 8, the press machine 20 has a die blade 21 for shearing the edge of the steel plate Ps. The die blade 21 has a recess 22 at its cutting edge that has the same shape as the bead 10. More specifically, multiple recesses 22 (see Figures 5-7), which are elliptical hemispherical indentations with the same shape as the bead 10, width Dw and depth Dd, are formed at intervals Di along the corner 21c between the upper surface 21a and the side surface 21b, which form the cutting edge of the die blade 21.

[0022] The steel plate Ps is placed on the upper surface 21a of the die blade 21, where the recess 22 is formed (Figure 9A). Next, a pad 23 with a flat lower side surface is placed on top of the steel plate Ps (Figure 9B). The steel plate Ps is pressed downwards (towards the die blade 21) by the pad 32 (Figure 9B). At this time, the lower side surface of the pad 23 and the side surface 21b of the die blade 21 are positioned to be approximately flush. In this state, the punch blade 24 moves along these sides from above (towards the pad 23) to below (towards the die blade 21) (Figure 9C). As a result, the punch blade 24 moves significantly downwards, beyond the upper surface 21a of the die blade 21 and exceeding the depth Dd of the recess 22.

[0023] As a result, the steel plate Ps is sheared along the side surface 21b of the die blade 21. At this time, the steel plate Ps is formed so that its end is recessed downward to match the shape of the recess 22 of the die blade 21 (Figure 9D). In this way, the steel plate Ps is sheared by the press machine 20, and simultaneously with the shearing, a bead 10 is formed at the end, becoming an outer part 2. By providing a bead 10 at the end of the steel plate Ps, even if the steel plate Ps is curved or bent, when the end is folded to form the flange 11, the stress generated in the flange 11 can be relieved and absorbed by the bead 10. This prevents unintended deformation of the area around the flange 11 of the outer part 2, which is a pressed part.

[0024] In this embodiment, when the pressed part is the outer part 2 of the bonnet 1, unintended deformation of the end of the outer part 2 is suppressed, allowing for precise flush alignment with the upper surface of the side body attached to the vehicle body adjacent to the bonnet 1. This improves the appearance of the vehicle body and reduces the man-hours required for alignment.

[0025] In particular, if the bending line 8 of the flange 11 on the outer part 2 is curved or bent when viewed from above, a large amount of stress is applied when forming the flange 11. Therefore, by providing a bead 10 at the end of the outer part 2 of the bonnet 1, which is a press-formed part with such a complex shape, deformation of the outer part 2 can be effectively suppressed and the flange 11 can be provided at the end.

[0026] In this embodiment, as described above, by using a die blade 21 with an uneven surface (a recess 22) on the cutting edge (corner portion 21c) and shearing the steel plate Ps with a press machine 20, an outer part 2 with a bead 10 at the end can be formed simultaneously with shearing. This reduces the number of manufacturing steps for the outer part 2 and makes it possible to easily manufacture an outer part 2 having a flange 11 formed by bending parts including curved or bent sections.

[0027] The uneven surfaces on the die blade 21 are formed by creating recesses 22 on the flat upper surface 21a. The protrusions are formed as flat surfaces, and the recesses 22 are formed as arcs that form part of an ellipsoid. This makes it easy to create uneven surfaces on the die blade 21, whose upper surface 21a is a flat surface.

[0028] Furthermore, as shown in Figure 8, in a front view with the side surface 21b of the die blade 21 facing forward, the width Dw of the recess 22 is greater than the depth Dd of the recess 22 from the top surface 21a. By making the recess 22 of the die blade horizontally elongated in this way, the formability when shearing the steel plate Ps with the press machine 20 to form the bead 10 is improved compared to making it semicircular.

[0029] Furthermore, the edge 21d of the recess 22 on the upper surface 21a of the die blade 21, that is, the boundary between the recess 22 and the flat upper surface 21a, may have a predetermined curvature R1. This suppresses stress concentration at the portion in contact with the edge 21d (boundary portion 10c of the outer part 2) when the steel plate Ps is sheared, and improves the strength at the boundary portion 10c of the outer part 2.

[0030] Furthermore, the outer part 2, which is manufactured by shearing and bending steel plate Ps using the press machine 20 to which this disclosure is applied, has a tensile strength of 270 [N / mm²], similar to SPCC or SPHC. 2 ] or more and 340 [N / mm 2 Since it is made of metal material below 340 [N / mm²], the bead 10 can be easily formed when shearing the steel plate Ps. 2 If the tensile strength of the steel plate Ps exceeds 270 [N / mm²], it is difficult to easily form the bead 10 when shearing the steel plate Ps. 2 If the value is less than ], even if a curved or bent steel plate Ps is folded to form a flange 11, unintended deformation is unlikely to occur, and there is little need to use the die blade 21 of the press machine 20 of this disclosure.

[0031] Furthermore, in this embodiment, the spacing Di of the recesses 22 provided on the die blade 21 may be set to a value corresponding to the tensile strength of the steel plate Ps. For example, the higher the tensile strength of the steel plate Ps, the shorter the spacing Di of the recesses 22 should be to make them closer together. This allows the recesses 22 to be appropriately set in response to the different ease (or difficulty) of deformation of the steel plate Ps depending on the tensile strength, and the bead 10 to be formed appropriately.

[0032] This disclosure is not limited to the embodiments described above. For example, the detailed shape of the recess 22 of the die blade 21 may differ from that of this embodiment. In this embodiment, the space between adjacent recesses 22 on the die blade 21 is a flat surface, but the space between adjacent recesses 22 may be a convex shape that protrudes upward.

[0033] Furthermore, this disclosure can be applied not only to hoods but also to press machines (shearing devices) used to manufacture various pressed parts for car bodies that have curved or bent sections. [Explanation of symbols]

[0034] 2. Outer parts (exterior panels) Ps steel plate 10 Beads (unevenness) 20. Press machine (shearing device) 21 die blades 21a Upper surface (flat part, convex part) 21d Edge (boundary) 22 Recessed portion (arc)

Claims

1. A die blade used in a shearing machine that shears a steel plate placed on the upper surface of a die blade to produce an outer panel part for a vehicle body having a curved or bent surface extending to the end, The upper surface of the die blade has an uneven portion along the end face which is the shearing position, and after shearing, an uneven portion corresponding to the shape of the uneven portion is formed on the end of the steel plate. A die blade for a shearing machine, characterized by the following features.

2. One of the recesses and protrusions that constitute the aforementioned uneven portion is formed as a flat portion, The other of the recess and the protrusion is formed as an arc portion that forms part of a sphere or ellipsoid. A die blade for a shearing apparatus as described in feature 1.

3. The aforementioned protrusion is formed as the aforementioned flat portion, The recess is formed as the arc portion, The die blade of the shearing apparatus according to feature 2.

4. In a front view of the die blade, the width of the arc portion is greater than the depth of the arc portion relative to the flat portion. The die blade of the shearing apparatus according to feature 3.

5. The boundary between the recess and the protrusion has a predetermined curvature when viewed from the front of the die blade. The die blade of the shearing apparatus according to feature 3.

6. The steel plate has a tensile strength of 270 [N / mm²]. 2 ] and 340 [N / mm 2 The following are metal components: A die blade for a shearing apparatus as described in feature 1.

7. The aforementioned uneven portions are formed at shorter intervals along the end face as the tensile strength of the steel plate being sheared increases. The die blade of the shearing apparatus according to feature 6.

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