Bending method

Abstract

To provide a bending method in which a punch is prevented from interfering with a protrusion part formed in a plate-like member.SOLUTION: The bending method comprises: a step in which a plate-like member 11, in which a protrusion part 13 protruding by a predetermined protrusion height from the plate-like member 11 is formed at a position away by a predetermined separation distance from a linear bent part formation position 12 at which a bent part 15 is formed, is placed on a lower metal mold 5 provided with a linear groove 5a having two oblique faces crossing with each other at a predetermined bending angle α and arranged with the groove 5a positioned below a tip of a punch 3, so that the bent part formation position 12 matches with a deepest portion of the groove 5a; and a step of moving a slide mechanism part 1 downward, making the tip of the punch 3 press the plate-like member 11 and forming the bent part 15 at the bent part formation position 12 at the bending angle α. In a state where the punch 3 presses the plate-like member 11 and the bent part 15 is formed in the plate-like member 11, an angle of the tip of the punch 3 is set so that a space is formed between the punch 3 and the protrusion part 13.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present disclosure relates to a bending method. [Background technology]

[0002] There are three known methods for bending metal plate members: partial bending, bottoming, and coining. Of these, partial bending is a method in which the metal plate member is sandwiched between a V-shaped die and a punch, and the punch presses the plate member in this state, thereby bending the metal plate member. Patent Document 1 proposes bending using partial bending. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-30285 Summary of the Invention [Problem to be solved by the invention]

[0004] Before bending, a metal plate member may be subjected to burring, for example, to secure a thread, which results in the formation of a protrusion on the surface of the metal plate member.

[0005] When bending a metal plate-shaped member, for example, by approximately 90° by pressing a punch against it, if such a protrusion is provided near the position where the punch makes contact, the punch may interfere with the protrusion during the bending process.

[0006] The present disclosure has been made to solve such problems, and its purpose is to provide a bending method in which, when bending a metal plate-shaped member, the punch does not interfere with a protrusion formed on the metal plate-shaped member. [Means for solving the problem]

[0007] The bending method according to the present disclosure includes the steps of: placing a punch having a predetermined tip angle at the lower end of a sliding mechanism that moves up and down in a space above a lower die; moving the sliding mechanism up; placing a plate-like member having a protrusion that protrudes from the plate-like member by a predetermined protrusion height at a position a predetermined distance from a linear bend formation position where the bend will be formed on a lower die that has a linear groove with two slopes that intersect at a predetermined bending angle and is positioned below the tip of the punch so that the bend formation position coincides with the deepest part of the groove; and moving the sliding mechanism down and pressing the plate-like member with the tip of the punch to form a bend at the bend formation position. The tip angle of the punch is determined so that there is a space between the punch and the protrusion when the punch is pressing against the plate-like member and a bend is formed in the plate-like member. [Effects of the Invention]

[0008] According to the bending method of the present disclosure, bending can be performed without the punch interfering with the protrusion. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing an example of the structure of a press machine used for bending according to the embodiment. [Figure 2] FIG. 2 is a perspective view showing an example of the structure of a punch used in the press machine in the embodiment. [Figure 3] FIG. 3 is a side view of the punch shown in FIG. 2 in the embodiment. [Figure 4] FIG. 2 is a perspective view showing one step of a bending method using a press in the embodiment. [Figure 5] 5 is a perspective view including a partially enlarged perspective view showing a step performed after the step shown in FIG. 4 in the embodiment. FIG. [Figure 6]FIG. 6 is a perspective view showing a step performed after the step shown in FIG. 5 in the embodiment. [Figure 7] FIG. 7 is a side view of the embodiment at the step shown in FIG. 6. [Figure 8] 8 is a side view showing a step performed after the steps shown in FIGS. 6 and 7 in the embodiment. FIG. [Figure 9] 9 is a perspective view showing a step performed after the step shown in FIG. 8 in the embodiment. [Figure 10] FIG. 10 is a side view of the step shown in FIG. 9 in the embodiment. [Figure 11] 11 is a partially enlarged side view of the step shown in FIG. 10 in the embodiment. FIG. [Figure 12] FIG. 4 is a partially enlarged side view for explaining the effect of the bending method in the embodiment. [Figure 13] FIG. 2 is a partially enlarged cross-sectional view showing an example of a metal plate member on which a bent portion is formed by a bending method in the embodiment. [Figure 14] FIG. 10 is a partially enlarged perspective view showing a metal plate member on which embossing has been applied as protrusions in the embodiment; [Figure 15] FIG. 2 is a partially enlarged perspective view showing a metal plate member that has been subjected to drawing to form a protrusion in the embodiment; [Figure 16] FIG. 10 is a partially enlarged perspective view showing a metal plate member having a shutter processing applied thereto as a protrusion in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiment A method for bending a metal plate-shaped member according to an embodiment will be described below. First, an example of a press machine for bending a metal plate-shaped member will be described.

[0011] As shown in FIG. 1, the press machine 1 includes a punch 3 as an upper die and a die 5 as a lower die. The punch 3 is fixed to a punch fixture 7. The punch fixture 7 has a first punch fixture 7a and a second punch fixture 7b. The punch 3 is sandwiched between the second punch fixture 7b and fixed to the first punch fixture 7a with a fixing bolt 9. As shown in FIGS. 2 and 3, for example, a hemming punch for hemming is used as the punch 3. The tip angle of the hemming punch is approximately 30°. The punch 3 used has a tip bending radius of 0.5 mm.

[0012] The punch 3 is pressed toward the die 5 by a sliding mechanism, which is, for example, a hydraulic press or a mechanical drive mechanism. Meanwhile, a V-shaped groove 5a that receives the tip of the punch 3 is formed in the die 5 along the direction in which the die 5 extends. The sliding mechanism moves vertically in the space above the die 5. The punch 3 is disposed at the lower end of the sliding mechanism. The V-shaped groove 5a is a linear groove having two inclined surfaces that intersect at a predetermined bending angle. The V-shaped groove 5a is provided in the die 5 so that the deepest part of the groove is located below the tip of the punch 3.

[0013] Next, we will explain an example of a method for bending a metal plate member using the above-mentioned press machine 1. As shown in Fig. 4, a metal plate member 11 to be bent is prepared. The thickness of the plate member 11 is, for example, 0.5 mm.

[0014] Next, as shown in FIG. 5, burring is performed on the metal plate member 11 to secure threads for, for example, a 2 mm thick screw (M2). This burring forms a burred portion 13 on the surface of the metal plate member 11 as a protrusion that protrudes from the surface. Here, the distance from the position where the punch 3 contacts the metal plate member 11, i.e., the bent portion forming position 12 (see FIG. 6) where the bent portion is formed, to the burred portion 13 is defined as distance L. This distance L will be described later. Distance L is a predetermined distance from the bent portion forming position 12 to the burred portion 13. The burred portion 13 is a protrusion that protrudes from the plate member 11 by a predetermined protrusion height.

[0015] 6 and 7, the metal plate member 11 is placed on the die 5 so that the bent portion forming position 12 in the metal plate member 11 is aligned with the V-shaped groove 5a formed in the die 5. The punch 3 is also placed above the die 5 (top dead center). Next, as shown in FIG. 8, the punch 3 is lowered (see arrow) so that the tip of the punch 3 abuts against the bent portion forming position 12 in the metal plate member 11.

[0016] Next, as shown in Figures 9 and 10, punch 3 presses metal plate member 11 at bent portion formation position 12 (see arrow). Punch 3 reaches bottom dead center, and bent portion 15 is formed at bent portion formation position 12. As shown in Figure 11, the bend angle α at bent portion 15 is, for example, 90°. A bending angle of 90° includes a manufacturing error (plus or minus several degrees). Thereafter, punch 3 is raised to its original position, and metal plate member 11 is removed from die 5. This completes the series of steps in the bending method for forming bent portion 15 in metal plate member 11.

[0017] In the above-described method for bending a metal plate-like member 11, by using a punch 3 having a relatively small tip angle of, for example, about 30°, it is possible to form a bent portion 15 in the metal plate-like member 11 at a position close to the burred portion 13 without interfering with the burred portion 13 as a protrusion. The tip angle of the punch 3 is an angle at which a space exists between the punch 3 and the burred portion 13 when the punch is pressing against the plate-like member 11 and a bent portion 15 is formed in the plate-like member 11. This will be explained below.

[0018] 12 shows a state in which the punch 3 is positioned at the bottom dead center and a bent portion 15 has been formed in the metal plate-shaped member 11. Here, the distance from the bent portion forming position 12 to the burred portion 13 is defined as distance L. The height of the burred portion 13 protruding from the surface of the plate-shaped member 11 is defined as height H. The angle between the plate-shaped member 11 and the punch 3, from the plate-shaped member 11 located on the side of the punch 3 where the burred portion 13 is provided, to the punch 3, is defined as angle φ. The angle of the tangent (tan) of the height H to the distance L is defined as angle θ.

[0019] In this state, the condition under which the punch 3 does not interfere with the burring processing portion 13 is that angle φ>angle θ (=tan -1 (H / L)). Conversely, if the height H of the burred portion 13, the angle β of the tip of the punch 3, and the bending angle α (see FIG. 11) are known, it is possible to set the distance L between the burred portion 13 and the bending portion forming position 12 where the bent portion 15 is formed, so that the punch 3 does not interfere with the burred portion 13. The dotted line connecting the top dead center and the bottom dead center is located at a position that bisects the bending angle of 90° (45° and 45°).

[0020] An example of a metal plate member having a bent portion formed by applying the above-described bending method will now be described in detail. As shown in Fig. 13, the thickness T of the metal plate member 11 is 0.5 mm. The plate member 11 is subjected to burring processing corresponding to a 2 mm thick screw (M2). The diameter of the burred portion 13 is approximately 2.5 mm. The height H of the burred portion 13 is 1.2 mm.

[0021] The length D from the center of the burring process portion 13 to the portion (rear surface) of the plate-shaped member 11 bent relative to the portion of the plate-shaped member 11 where the burring process portion 13 is provided is 4.0 mm. The distance L (= 4.0 - 0.5 - 2.5 / 2) between the bent portion forming position 12 (see FIG. 12) and the burring process portion 13 is 2.25 mm. In this case, the angle θ is approximately 28.1°. As shown in FIG. 12, when the angle β of the tip of the punch is 30°, the angle φ is larger than the angle θ, and the punch 3 does not interfere with the burring process portion 13. The tip angle of the punch 3 may be within a predetermined range including 30°, such as 27° to 33°.

[0022] In the bending method described above, when forming a bent portion at a bend angle of 90° in a metal plate-shaped member, a hemming punch is used as punch 3 having a tip angle of approximately 30°, rather than a punch having a tip angle of approximately 88° to 90°. As a result, even if a protrusion such as burring portion 13 is provided near the position where bent portion 15 is to be formed, bent portion 15 at a bend angle of 90° can be formed without punch 3 interfering with burring portion 13.

[0023] In addition, punching, including burring, can be performed before bending, reducing the overall processing cost. Furthermore, by using an existing punch 3 with a relatively small tip angle, such as a hemming punch, the cost required for bending can be reduced. Also, by using a hemming punch for 90° bending, the number of dies that need to be managed can be reduced.

[0024] In the above-described method for bending a metal plate member, a metal plate member having a burred portion 13 formed thereon as a protrusion has been described as an example. The protrusion is not limited to a burred portion 13, and the method can also be applied to bending a metal plate member 11 having a drawn portion 17 formed thereon, as shown in Fig. 14. Furthermore, the method can also be applied to a metal plate member 11 having an embossed portion 19 formed thereon, as shown in Fig. 15. Furthermore, the method can also be applied to a metal plate member 11 having a shutter portion 21 formed thereon, as shown in Fig. 16.

[0025] Furthermore, in the above-described method for bending a metal plate-like member, a hemming punch has been described as an example of the punch 3. When an existing punch is used as the punch 3, the distance L at which the punch 3 does not interfere with the burring process portion 13, etc., can be set based on the angle β of the tip of the punch 3, the height H of the protrusions of the burring process portion 13, etc., and the bending angle α of the metal plate-like member.

[0026] On the other hand, if the distance L from the bend forming position 12 (see Figure 12) to the burring processing portion 13 has already been set, a punch having a tip angle β that does not interfere with the burring processing portion 13, etc. can be selected based on the distance L, the height H of the protrusions such as the burring processing portion 13, and the bending angle α of the metal plate-like member.

[0027] The bending methods described in the embodiments can be combined in various ways as required.

[0028] Various aspects of the present disclosure are summarized below as appendices.

[0029] [Appendix 1] a step of placing a punch having a determined tip angle at the lower end of a slide mechanism that moves up and down in a space above a lower die; a step of moving the slide mechanism upward, and placing the plate-like member, on which a protrusion protruding from the plate-like member by a predetermined protrusion height is formed at a position a predetermined distance from a linear bent portion forming position where the bent portion is to be formed, on the lower die, which is provided with a linear groove having two inclined surfaces intersecting at a predetermined bending angle and is positioned so that the groove is located below the tip of the punch, so that the bent portion forming position coincides with the deepest part of the groove; a step of moving the slide mechanism downward and pressing the plate-like member with the tip of the punch to form the bent portion at the bent portion forming position at the bend angle, a tip angle of the punch being determined so that a space exists between the punch and the protrusion when the punch presses the plate-like member and the bent portion is formed in the plate-like member. [Appendix 2] 2. The bending method according to claim 1, wherein the tip angle of the punch is within a predetermined range including 30°. [Appendix 3] 4. The bending method according to claim 3, wherein a hemming punch is used as the punch. [Appendix 4] 4. The bending method according to any one of claims 1 to 3, wherein the bending angle is 90°. [Appendix 5] 5. The bending method according to any one of claims 1 to 4, wherein the protrusion is a burred portion formed by subjecting the plate-like member to burring. [Appendix 6] 5. The bending method according to any one of claims 1 to 4, wherein the protrusion is a drawn portion formed by drawing the plate-like member. [Appendix 7] 5. The bending method according to any one of claims 1 to 4, wherein the protrusion is an embossed portion formed by embossing the plate-like member. [Appendix 8] 5. The bending method according to any one of claims 1 to 4, wherein the protrusion is a shutter processed portion formed by subjecting the plate-like member to shutter processing.

[0030] The embodiments disclosed herein are examples and are not intended to be limiting. The scope of the present disclosure is defined by the claims, not the scope described above, and is intended to include all modifications within the meaning and scope equivalent to the claims. [Industrial Applicability]

[0031] The present disclosure is effectively utilized in bending a metal plate member using a punch. [Explanation of symbols]

[0032] 1 press bending machine, 3 punch, 5 die, 5a V-shaped groove, 7 punch fixture, 7a first punch fixture, 7b second punch fixture, 9 fixing bolt, 11 plate-shaped member, 12 bending portion forming position, 13 burring processing portion, 15 bending portion, 17 drawing processing portion, 19 embossing processing portion, 21 shutter processing portion, H height, L, D length, T thickness, α bending angle, β tip angle, θ, φ angles.

Claims

1. a step of placing a punch having a determined tip angle at the lower end of a slide mechanism that moves up and down in a space above a lower die; a step of moving the slide mechanism upward, and placing the plate-like member, on which a protrusion protruding from the plate-like member by a predetermined protrusion height is formed at a position a predetermined distance from a linear bent portion forming position where the bent portion is to be formed, on the lower die, which is provided with a linear groove having two inclined surfaces intersecting at a predetermined bending angle and is positioned so that the groove is located below the tip of the punch, so that the bent portion forming position coincides with the deepest part of the groove; a step of moving the slide mechanism downward and pressing the plate-like member with the tip of the punch to form the bent portion at the bent portion forming position at the bend angle, a tip angle of the punch being determined so that a space exists between the punch and the protrusion when the punch presses the plate-like member and the bent portion is formed in the plate-like member.

2. 2. The bending method according to claim 1, wherein the tip angle of the punch is within a predetermined range including 30 degrees.

3. 3. The bending method according to claim 2, wherein the punch is a hemming punch.

4. The bending method according to any one of claims 1 to 3, wherein the bending angle is 90°.

5. 4. The bending method according to claim 1, wherein the protrusion is a burred portion formed by subjecting the plate-like member to burring.

6. 4. The bending method according to claim 1, wherein the protrusion is a drawn portion formed by drawing the plate-like member.

7. 4. The bending method according to claim 1, wherein the protrusion is an embossed portion formed by embossing the plate-like member.

8. The bending method according to any one of claims 1 to 3, wherein the protrusion is a shutter processed portion formed by performing shutter processing on the plate-like member.

Images