Press forming method

Abstract

To provide a press molding method that can improve manufacturing efficiency. [Solution] The present invention includes a pre-bending step in which, with the plate-shaped member 7 fixed by a fixing member 2 and with the edge of the plate-shaped member 7 in contact with a pre-molding surface 3c, the molding member 3 and / or fixing member 2 are moved in a predetermined direction by a first drive unit 41, the plate-shaped member 7 is bent to one side in the predetermined direction to form a pre-bent portion 82 on the edge of the plate-shaped member 7, and the pre-bent portion 82 is positioned between the molding side surface 3a and the fixing side surface 2a; and a main bending step in which, with the plate-shaped member 7 fixed by the fixing member 2, the molding member 3 is brought closer to the fixing member 2 by a second drive unit 42, the pre-bent portion 82 is bent with the tip surface 82a in contact with the pressing surface 3b so that the tip surface 82a of the pre-bent portion 82 is pressed, and the bent pre-bent portion 82 is sandwiched between the fixing side surface 2a and the molding side surface 3a.

Description

Technical Field

[0001] The present invention relates to a press forming method.

Background Art

[0002] As a press forming method, for example, as described in Japanese Patent No. 7543506, there is disclosed a method of forming while applying a compressive force to the end face of a preformed product. According to this method, effects such as suppression of springback are achieved.

Prior Art Literature

Patent Literature

[0003]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] The above-described press forming method includes a pre-bending step and a specific bending step. The inventor of the present invention considered that if these two steps can be performed through a series of operations using one common apparatus, manufacturing efficiency can be improved, and thus completed the present invention. An object of the present invention is to provide a press forming method capable of improving manufacturing efficiency.

Means for Solving the Problem

[0005] The present invention relates to a press forming method using a press forming apparatus comprising: a fixing member having a fixing side surface shaped according to the target shape for forming a plate-like member; a forming member having a forming side surface and a pressing surface shaped according to the target shape, and a pre-forming surface; a first drive unit for moving the fixing member and / or the forming member in a predetermined direction; and a second drive unit for moving the fixing member and / or the forming member in a direction intersecting the predetermined direction, wherein the plate-like member is fixed by the fixing member and the edge of the plate-like member is in contact with the pre-forming surface, and the first drive unit moves the forming member and / or the fixing The process includes: a pre-bending step in which a fixed member is moved in the predetermined direction, the plate-shaped member is bent to one side in the predetermined direction to form a pre-bent portion at the edge of the plate-shaped member, and the pre-bent portion is positioned between the molded side and the fixed side; and a main bending step in which, with the plate-shaped member having the pre-bent portion formed thereon fixed by the fixed member in the same manner as the pre-bending step, the molded member is brought relatively closer to the fixed member by the second drive unit, the pre-bent portion is bent while maintaining a state in which the tip surface of the pre-bent portion is pressed against the pressing surface, and the pre-bent portion is sandwiched between the fixed side and the molded side. [Effects of the Invention]

[0006] According to the present invention, in the pre-bending process, the plate-shaped member is bent to include a pre-bent portion, and this pre-bent portion is positioned between the molded side and the fixed side. This allows the main bending process to be performed continuously from the pre-bending process (without the need for an intervening separate process). In the main bending process, the pre-bent portion is bent while the leading edge is pressed. This creates stress distributions in and around the pre-bent portion that tend to spring back and stress distributions that tend to spring back, and the cancellation of these stress distributions makes it possible to reduce and suppress springback overall. Thus, according to the present invention, since the pre-bending process and the main bending process are performed in a series of operations using a single common device, it is possible to improve manufacturing efficiency. [Brief explanation of the drawing]

[0007] [Figure 1] This is a conceptual diagram of a plate-shaped member, a pre-molded product, and a molded product according to the first embodiment. [Figure 2] This is a diagram showing the configuration of the press molding apparatus according to the first embodiment. [Figure 3] This is a conceptual diagram illustrating the press forming method of the first embodiment. [Figure 4] This is a conceptual diagram illustrating the press forming method of the first embodiment. [Figure 5] This is a conceptual diagram illustrating the press forming method of the first embodiment. [Figure 6] This is a diagram showing the configuration of a burring apparatus according to the second embodiment. [Figure 7] This is a conceptual diagram illustrating the manufacturing method for a burring member according to the second embodiment. [Figure 8] This is a conceptual diagram illustrating a modified version of this embodiment. [Modes for carrying out the invention]

[0008] Hereinafter, a press molding apparatus 1 and a press molding method, which are embodiments of the present invention, will be described in detail with reference to the figures. It should be noted that, in addition to the embodiments described below, the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0009] (First Embodiment) As shown in Figure 1, in press forming, a preformed product 8 is formed from a plate-shaped member 7 in the pre-bending process, and a molded product 9 is formed from the preformed product 8 in the main bending process. The plate-shaped member 7 is a flat metal member. The plate-shaped member 7 may be decorated with various ornaments or patterns.

[0010] The pre-molded product 8 comprises a flat plate portion 81 and a pre-bent portion 82 that is bent from the flat plate portion 81 to one side in a predetermined direction. The flat plate portion 81 is flat and can also be called the top plate portion. The pre-bent portion 82 extends diagonally to the flat plate portion 81 and can also be called the inclined wall portion. The angle θ1 between the pre-bent portion 82 and the extension line (extension plane) of the flat plate portion 81 is greater than 0 degrees and less than 90 degrees. Approximately, the angle θ1 is between 10 degrees and 80 degrees.

[0011] The molded product 9 comprises a flat plate portion 81, a curved shoulder R portion 92 extending from the flat plate portion 81, and a vertical wall portion 93 continuous from the flat plate portion 81 via the shoulder R portion 92. The angle θ2 between the extension of the flat plate portion 81 and the extension of the vertical wall portion 93 is greater than the angle θ1. In this example, the angle θ2 is 90 degrees (θ1 < θ2 ≤ 90 degrees). In the following description of the first embodiment, the predetermined direction is defined as the up-and-down direction, and the direction perpendicular to the up-and-down direction is defined as the left-and-right direction.

[0012] As shown in Figure 2, the press forming apparatus 1 comprises a fixing member 2, a forming member 3, a first drive unit 41, and a second drive unit 42. The fixing member 2 is a mold member that fixes the plate-shaped member 7. The fixing member 2 only needs to continuously and substantially fix the flat plate portion 81 during forming. In other words, the flat plate portion 81 may move slightly relative to the fixing member 2 due to the force applied to the flat plate portion 81 during forming, as long as it does not adversely affect the forming process.

[0013] The fixing member 2 comprises a first fixing member 21 and a second fixing member 22 positioned vertically opposite to the first fixing member 21. The fixing member 2 secures the plate-shaped member 7 by sandwiching it vertically between the first fixing member 21 and the second fixing member 22. For example, the first fixing member 21 is a pad and the second fixing member 22 is a punch.

[0014] The fixing member 2 comprises a fixing side surface 2a having a shape corresponding to the target shape for forming the plate-like member 7. The target shape is the shape of the molded product 9 targeted in press forming. The fixing side surfaces 2a are formed on the left and right side surfaces of the second fixing member 22. The fixing side surface 2a protrudes from the upper end portion of the side surface of the second fixing member 22 to correspond to the target shape. The fixing side surface 2a comprises a portion having a convex arc-shaped cross-section (convex cross-section portion) 2a1 corresponding to the shoulder R portion 92 of the molded product 9, and a planar portion (straight cross-section portion) 2a2 corresponding to the vertical wall portion 93 of the molded product 9.

[0015] The first fixing member 21 and / or the second fixing member 22 is configured to be movable in the up-down direction. The plate-like member 7 is clamped and fixed by the vertical movement of the first fixing member 21 and / or the second fixing member 22. The drive source for the first fixing member 21 and / or the second fixing member 22 may be the first drive unit 41. In the pre-bending step and the final bending step, the fixing member 2 continuously fixes the plate-like member 7.

[0016] The forming member 3 is a mold member, and is disposed on both left and right sides of the fixing member 2. The forming member 3 comprises a forming side surface 3a and a pressing surface 3b having shapes corresponding to the target shape, and a pre-forming surface 3c. The forming side surface 3a is formed on a side surface of the forming member 3 that faces (in the left-right direction) the fixing member 2. The forming side surface 3a is recessed from the side surface of the forming member 3 along the target shape. The upper portion of the forming side surface 3a has a curved shape corresponding to the target shape of the shoulder R portion 92. The forming side surface 3a comprises a portion having a concave arc-shaped cross-section (concave cross-section portion) 3a1 corresponding to the shoulder R portion 92 of the molded product 9, and a planar portion (straight cross-section portion) 3a2 corresponding to the vertical wall portion 93 of the molded product 9.

[0017] The pressing surface 3b is formed at the lower end (the side far from the plate-like member 7) of (the straight cross-section portion 3a2 of) the forming side surface 3a. The pressing surface 3b is an upper end surface of a protruding portion 31 that protrudes from the lower end portion of the forming side surface 3a toward the fixing member 2. A bent surface (here, a surface bent at 90 degrees) is formed by the pressing surface 3b whose perpendicular extends in the up-down direction and the straight cross-section portion 3a2 of the forming side surface 3a whose perpendicular extends in the left-right direction.

[0018] A recess is formed on the side surface of the forming member 3 by the forming side surface 3a and the pressing surface 3b. The forming side surface 3a and the pressing surface 3b of the right forming member 3 form a recess recessed rightward on the left side surface, and the forming side surface 3a and the pressing surface 3b of the left forming member 3 form a recess recessed leftward on the right side surface.

[0019] The pre-forming surface 3c is formed at a corner of the forming member 3. The pre-forming surface 3c is a surface of a corner on the fixing member 2 side among the lower end portions of the forming member 3. The pre-forming surface 3c is located below the forming side surface 3a in the forming member 3 (on the side of the plate-like member 7 before the pre-bending step). The corner is chamfered and has a curved shape. The pre-forming surface 3c is a curved surface of the corner of the forming member 3. The pre-forming surface 3c can also be referred to as a surface of the lower end portion of the protruding portion 31. The pre-forming surface 3c can also be referred to as a portion of the forming member 3 that first abuts against the plate-like member 7.

[0020] The first driving unit 41 is a device that moves the fixing member 2 and / or the forming member 3 in a predetermined direction. It can be said that the first driving unit 41 relatively moves the forming member 3 in the vertical direction (predetermined direction) with respect to the fixing member 2. The first driving unit 41 of the first embodiment is configured to simultaneously move the two left and right forming members 3 in the vertical direction. During forming, the first driving unit 41 moves the forming member 3 toward the side approaching the plate-like member 7 (the fixing portion of the fixing member 2) in the vertical direction. The first driving unit 41 may move the fixing member 2 in the vertical direction. It can be said that the first driving unit 41 is a device that moves the fixing member 2 and / or the forming member 3 such that the plate-like member 7 and the forming member 3 (the pre-forming surface 3c) approach each other.

[0021] The second drive unit 42 is a device that moves the fixed member 2 and / or the molding member 3 in the left-right direction (a direction intersecting a predetermined direction). The second drive unit 42 moves the fixed member 2 and / or the molding member 3 so that they move closer to or further apart from each other. In this embodiment, the second drive unit 42 is configured to move the molding member 3. The second drive unit 42 moves the molding member 3 so that it approaches the fixed member 2. The second drive unit 42 moves the right molding member 3 to the left and the left molding member 3 to the right. The drive source for the first drive unit 41 and the second drive unit 42 may be, for example, a mechanical or fluid pressure type, such as an electric motor.

[0022] As an example, let's consider the case where the molding member 3 is part of a cam slider, as shown by the dashed line in Figure 2. The molding member 3 is provided with an inclined wall portion 32 that engages with a cam driver 5. A cam driver 5 with a shape corresponding to the inclined wall portion 32 is provided at a position opposite the molding member 3 in the vertical direction. When the cam driver 5 moves upward while the cam driver 5 and the inclined wall portion 32 of the molding member 3 are engaged, the molding member 3 moves in the left-right direction. The second drive unit 42 is a device that moves the cam driver 5 upward relative to the molding member 3. The first drive unit 41 and the second drive unit 42 may be a single (common) drive unit. The initial position of the molding member 3 is the position furthest from the fixed member 2 within the left-right range of motion. That is, in the initial position, the left molding member 3 is configured to be movable only to the right, and the right molding member 3 is configured to be movable only to the left.

[0023] As shown in Figures 3 and 4, the pre-bending process involves fixing the plate-shaped member 7 with the fixing member 2 and bringing the edge of the plate-shaped member 7 into contact with the pre-molding surface 3c, while moving the molding member 3 and / or fixing member 2 vertically using the first drive unit 41, bending the plate-shaped member 7 to one side in the vertical direction (downward in this case) to form a pre-bent portion 82 on the edge of the plate-shaped member 7, and positioning the pre-bent portion 82 between the molding surface 3a and the fixing surface 2a.

[0024] In this bending process, similar to the pre-bending process, the plate-shaped member 7 (i.e., pre-molded product 8) with the pre-bent portion 82 formed thereon is fixed by the fixing member 2, and the molding member 3 is brought (relatively) closer to the fixing member 2 by the second drive unit 42, and the pre-bent portion 82 is bent while maintaining a state in which the tip surface 82a of the pre-bent portion 82 is pressed against the pressing surface 3b, thereby sandwiching the pre-bent portion 82 between the fixing side surface 2a and the molding side surface 3a.

[0025] Figure 3(a) shows the state in which the central portion of the plate-shaped member 7 is fixed to the fixing member 2. This fixed state continues until the molded product 9 is formed. Figure 3(b) shows the state in which the molding member 3 has moved downward from its initial position and the pre-molding surface 3c is in contact with the edge of the plate-shaped member 7.

[0026] Figure 3(c) shows that the molding member 3 has moved further downward from the state shown in Figure 3(b), and the plate-shaped member 7 has been bent by the pre-molding surface 3c. Figure 4(d) shows that the molding member 3 has moved further downward from the state shown in Figure 3(c), and the edge of the bent plate-shaped member 7 is located between the molded side surface 3a and the fixed side surface 2a.

[0027] As the molded member 3 moves downward from Figure 3(c) to Figure 4(d), the tip of the plate-shaped member 7 slides against the side surface of the molded member 3 (the protruding end surface of the protruding portion 31). When the plate-shaped member 7 reaches a position corresponding to the molded side surface 3a, in this example it spreads slightly, and the tip surface 82a approaches the molded side surface 3a. As shown in Figures 3(b) to 4(d), the plate-shaped member 7 is bent by contact with the pre-molded surface 3c, forming a pre-molded product 8 having a pre-bent portion 82. The flow from Figure 3(b) to Figure 4(d) corresponds to the pre-bending process.

[0028] Figure 4(e) shows the state in which the molding member 3 moves towards the fixing member 2 in the left-right direction, and the tip surface 82a of the pre-bent portion 82 comes into contact with the pressing surface 3b. From Figure 4(d) to Figure 4(e), as the molding member 3 moves, the tip of the pre-bent portion 82 first comes into contact with the molding side surface 3a, and as the molding member 3 moves, the pre-bent portion 82 is bent, and the tip of the pre-bent portion 82 slides downward. Then the tip surface 82a of the pre-bent portion 82 comes into contact with the pressing surface 3b.

[0029] Figure 4(f) shows the state in which the molding member 3 is in contact with the fixing member 2, the pre-molded product 8 is sandwiched between the molding member 3 and the fixing member 2, and the molded product 9 is formed. In Figure 4(f), the pre-bent portion 82 is sandwiched between the molding side surface 3a and the fixing side surface 2a and processed into a shoulder radius portion 92 and a vertical wall portion 93. The end of the pressing surface 3b is inserted below the fixing side surface 2a. The flow from Figure 4(e) to Figure 4(f) corresponds to the main bending process.

[0030] As shown in Figure 5, in this bending process, the pre-bent portion 82 is bent while its tip surface 82a is pressed from the pressing surface 3b. The white arrows in Figure 5 roughly indicate the direction of the force. During this bending process, a force (compressive force) is applied to the tip surface 82a from the pressing surface 3b toward the base of the pre-bent portion 82. The length of the pre-bent portion 82 is slightly greater than the length of the shoulder radius portion 92 and the vertical wall portion 93. In this bending process, the pre-bent portion 82 is compressed by the compressive force. The compressive force can be described as a force that reduces the length of the pre-bent portion 82. In this bending process, the tip surface 82a can also be said to be subjected to end pressure. As a result, the length of the pre-bent portion 82 becomes smaller. In other words, the pre-bent portion 82 has a compression allowance relative to the target shape. The pre-bent portion 82 is longer than the target shape by the compression allowance. In this bending process, the pre-formed product 8 can be said to ultimately become the molded product 9 after being pressed.

[0031] According to this bending process, stress distributions that tend to spring back and stress distributions that tend to spring back are generated in the pre-bent portion 82 and its surrounding area. These stress distributions cancel each other out, making it possible to reduce and suppress springback overall. For example, as shown in Figure 1, in the shoulder R portion 92 and its surrounding area, a spring-go stress distribution is generated at position X1 on the flat plate portion 81 side, a spring-back stress distribution is generated at the central position X2 of the curved portion, and a spring-go stress distribution is generated at position X3 on the tip surface 82a side. These stress distributions cancel each other out, reducing and suppressing springback of the shoulder R portion 92. According to the first embodiment, it can also be said that plastic buckling is generated in the pre-bent portion 82 at least partially.

[0032] According to the first embodiment, in the pre-bending process, the plate-shaped member 7 is bent to include a pre-bent portion 82, and the pre-bent portion 82 is positioned between the molded side surface 3a and the fixed side surface 2a. This allows the main bending process to be performed continuously from the pre-bending process (without intervening in any other process).

[0033] Conventionally, when the main bending process is performed using equipment different from the equipment used in the preliminary bending process, the preliminary molded product 8 must be molded and then set in a separate piece of equipment. However, according to the first embodiment, the two bending processes are performed in a continuous operation without changing equipment as described above, and without the need for transporting and setting the preliminary molded product 8. This is extremely advantageous in terms of production automation and improves the manufacturing efficiency of molded products with suppressed springback. Thus, according to the first embodiment, since the preliminary bending process and the main bending process are performed in a series of operations using a single common piece of equipment, it is possible to improve manufacturing efficiency.

[0034] (Second embodiment: Burring member) The press forming method of the first embodiment can also be applied to the manufacture of burring members using a burring processing device 6 as a press forming apparatus. As shown in Figure 6, the burring processing device 6 is an apparatus that processes a pre-bent portion 82 of a pre-formed product 8 into a flange of the target shape. The pre-formed product 8 comprises a flat plate portion 81, a hole 81a formed in the flat plate portion, and a pre-bent portion 82 formed by the peripheral edge of the hole 81a rising from the flat plate portion 81. The pre-bent portion 82 of the second embodiment has a flange shape with a rising angle (bending angle) of less than 90 degrees, and can also be called a pre-flange portion.

[0035] The burring apparatus 6 comprises a fixing member 61, a cam driver 62, a drive unit 63, and a cam slider 64. The fixing member 61 is a member that fixes the flat plate portion 81, including the peripheral edge of the pre-bent portion 82. Similar to the first embodiment, the fixing by the fixing member 61 is performed continuously during forming and only substantial fixing is required. The cam driver 62 is an axial member that extends axially (here in the vertical direction) along the central axis of the hole 81a, with a tip 62a on one axial side (up) and a base end 62b on the other axial end (down). At the tip portion of the cam driver 62 that engages with the cam slider 64, the diameter increases from the tip 62a towards the base end 62b. The drive unit 63 is a device that moves the cam driver 62 and / or the cam slider 64 in the axial direction. The drive unit 63 moves the cam driver 62 and / or the cam slider 64 so that they move closer together or further apart relative to each other. Furthermore, the drive unit 63 is configured to allow the fixing member 61 to move in the axial direction. Hereinafter, the movement of the cam driver 62 and / or the cam slider 64 by the drive unit 63 so that the base end 62b of the cam driver 62 approaches the cam slider 64 will also be referred to as the "forming relative movement" of the cam driver 62. The forming relative movement may be movement of the cam driver 62 in one axial direction, movement of the cam slider 64 in the other axial direction, or movement of both the cam driver 62 and the cam slider 64 in the axial direction. In this embodiment, as an example of forming relative movement, the cam slider 64 does not move in the axial direction when the cam driver 62 is moved to one axial side. The relative molding movement can also be described as the cam driver 62 moving axially relative to the cam slider 64 so that the cam slider 64 moves in the direction of expansion (radially outward). The drive unit 41 can move the cam slider 64 axially together with the fixed member 61.

[0036] The cam slider 64 is arranged to work with the cam driver 62 and comprises a plurality of cam teeth 641, each having a cam outer surface 641a positioned on the inner circumference side of the pre-bent portion 82 in a shape corresponding to the target shape. Each cam outer surface 641a includes a portion with a concave arc cross-section (concave cross-section) 641a1 corresponding to the curved portion between the flat plate portion 81 of the molded product 9 and the flange, and a cylindrical portion (straight cross-section) 641a2 corresponding to the flange of the molded product 9 (see Figure 7).

[0037] Each cam tooth 641 moves to push the pre-bent portion 82 outward as the cam driver 62 moves axially to one side (relative forming movement). The fixing member 61 includes a first fixing member 611 having a through hole at a position corresponding to the hole 81a, and a second fixing member 612 having a through hole at a position corresponding to the hole 81a and positioned to face the first fixing member 611 in the axial direction. The fixing member 61 fixes the flat plate portion 81 by sandwiching it axially between the first fixing member 611 and the second fixing member 612.

[0038] The first fixing member 611 comprises a molded inner circumferential surface 6a and a contact surface 6b. The molded inner circumferential surface 6a is positioned to face each cam outer circumferential surface 641a via a pre-bent portion 82. The molded inner circumferential surface 6a comprises a portion with a convex arc cross-section (convex cross-section) 6a1 corresponding to the curved portion between the flat plate portion 81 of the molded product 9 and the flange, and a cylindrical portion (straight cross-section) 6a2 corresponding to the flange of the molded product 9 (see Figure 7).

[0039] The contact surface 6b protrudes from the upper end (the side furthest from the plate-like member 7) of the molded inner circumferential surface 6a (the straight section 6a2 of the cross-section). The contact surface 6b is a plane that contacts the tip surface 82a of the pre-bent portion 82 so that when the pre-molded product 8 is fixed to the fixing member 61 and the pre-bent portion 82 is bent by the movement of each cam tooth 641 to form the flange, a compressive force toward the root of the pre-bent portion 82 is applied to the tip surface 82a of the pre-bent portion 82 as the pre-bent portion 82 is bent. The molded inner circumferential surface 6a and the outer circumferential surfaces 641a of each cam are configured to sandwich the pre-bent portion 82 as the movement of each cam tooth 641 occurs.

[0040] The hole 81a, which is a through hole formed in the plate-shaped member 7, is circular in shape (when viewed in the axial direction). The target shape of the flange is cylindrical. The pre-bent portion 82 rises at an angle θ (0 degrees < θ < 90 degrees, for example, 10 degrees ≤ θ ≤ 80 degrees) relative to the extension line of the flat portion 81. With movement of the cam driver 62 in one axial direction, each cam tooth 641 moves radially outward. The cam slider 64 is composed of multiple cam teeth 641, and in this example, it is composed of 12 cam teeth 641 of the same shape. If the hole 81a is circular, three or more cam teeth 641 are preferable. Grooves corresponding to the cam teeth 641 are formed in the cam driver 62.

[0041] The method for manufacturing a burring member using the burring processing apparatus 6 includes a preliminary bending step and a main bending step, similar to the press forming method described above. As shown in Figure 7, the preliminary bending step involves the drive unit 63 moving the fixing member 61 to the other axial position (and / or moving the cam slider 64 to one axial position) while the plate-shaped member 7 is fixed to the fixing member 61, bringing the peripheral edge of the hole 81a in the plate-shaped member 7 into contact with the outer edge 641b of the cam slider 64, and sliding the plate-shaped member 7 against the cam slider 64 to bend the peripheral edge of the hole 81a, thereby forming a preliminary bend 82 between the formed inner circumferential surface 6a and the cam outer circumferential surface 641a.

[0042] In this bending process, with the fixing member 61 fixing the flat plate portion 81 including the peripheral edge of the pre-bent portion 82, and with the tip surface 82a of the pre-bent portion 82 in contact with the contact surface 6b, the cam driver 62 is moved axially to one side (relative forming movement) to move each cam tooth 641, and with a compressive force applied from the contact surface 6b to the tip surface 82a of the pre-bent portion 82, the pre-bent portion 82 is bent, and the pre-bent portion 82 is sandwiched between the outer circumferential surfaces 641a of each cam and the inner circumferential surface 6a of the forming to form a flange.

[0043] The forming inner circumferential surface 6a of the burring device 6 corresponds to the fixed side surface 2a of the press forming device 1. The cam outer circumferential surface 641a of the burring device 6 corresponds to the forming side surface 3a of the press forming device 1. The contact surface 6b of the burring device 6 corresponds to the pressing surface 3b of the press forming device 1. The outer edge 641b (and cam outer circumferential surface 641a) of the cam slider 64 of the burring device 6 corresponds to the pre-forming surface 3c of the press forming device 1. The outer edge 641b of the cam slider 64 is located above or above the cam outer circumferential surface 641a (on the side of the plate-shaped member 7 before the pre-bending process). The drive unit 63 of the burring device 6 corresponds to the first drive unit 41 and the second drive unit 42 of the press forming device 1. The cam slider 64 of the burring device 6 corresponds to the forming member 3 of the press forming device 1.

[0044] The pre-bending process in the burring apparatus 6 is similar to the pre-bending process in the press forming apparatus 1. With the plate-shaped member 7 fixed by the fixing member 61 and the inner edge of the plate-shaped member 7 (periphery of the hole 81a) in contact with the outer edge 641b (pre-forming surface 3c), the drive unit 63 (first drive unit 41) moves the cam slider 64 (forming member 3) relative to the fixing member 61 in the axial direction (predetermined direction), bending the plate-shaped member 7 in the axial direction to form a pre-bent portion 82 on the inner edge of the plate-shaped member 7, and positioning the pre-bent portion 82 between the outer circumferential surface 641a (forming side surface 3a) and the inner circumferential surface 6a (fixing side surface 2a) of each cam.

[0045] The main bending process in the burring apparatus 6 is similar to the main bending process in the press forming apparatus 1, and similar to the pre-bending process, the plate-shaped member 7 with the pre-bent portion 82 formed is fixed by the fixing member 61. The drive unit 63 (second drive unit 42) brings the cam slider 64 (forming member 3) closer to the fixing member 61, and the pre-bent portion 82 is bent while maintaining the state in which the tip surface 82a of the pre-bent portion 82 is pressed against the contact surface 6b (pressing surface 3b). This process can be described as a process in which the pre-bent portion 82 is sandwiched between the forming inner circumferential surface 6a (fixing side surface 2a) and the outer circumferential surfaces 641a (forming side surface 3a) of each cam. Therefore, the same effects as the press forming method of the first embodiment are achieved in this burring member manufacturing method as well.

[0046] (Common characteristics) In the molded product, curved sections (e.g., shoulder radius sections) are formed between flat sections and sections angled relative to the flat sections (e.g., vertical wall sections or flange sections) to connect them. The molded side surface and fixed side surface have sections formed in a shape corresponding to the curved sections.

[0047] The fixed side surface 2a (molded inner circumferential surface 6a) has a convex cross-section portion 2a1 (6a1) corresponding to the shape of the curved portion of the molded product (target shape). The molded side surface 3a (cam outer circumferential surface 641a) has a concave cross-section portion 3a1 (641a1) corresponding to the shape of the curved portion of the molded product and corresponding to the convex cross-section portion 2a1 (6a1). Each of these surfaces further has straight cross-section portions 2a2, 6a2, 3a2, and 641a2 corresponding to the shape of other parts of the molded product (parts with a straight cross-section). In this bending process, the base portion of the pre-bent portion 82 is sandwiched between the convex cross-section portion and the concave cross-section portion.

[0048] The pre-forming surface 3c (outer edge 641b) is formed at the corner of the forming member 3 (cam slider 64) and is located on the plate-like member 7 side of the forming side surface 3a (cam outer peripheral surface 641a) before the pre-bending process. The pressing surface 3b (contact surface 6b) is at the end of the forming side surface 3a (cam outer peripheral surface 641a) and is located at the end furthest from the plate-like member 7 before the pre-bending process.

[0049] The main bending process of this embodiment can be said to include a final pressing process. The final pressing process is performed immediately before the completion of the main bending process (for example, after the remaining bending amount is a few mm or less), in which the pre-bent portion 82 is bent in the same way as the main bending process, and finally the pre-bent portion 82 is sandwiched between the fixing side 2a and the molding side 3a. As an example, in the final pressing process, the fixing member 2 is in a so-called bottomed-out state, and the fixing (or fixing force) of the flat plate portion 81 by the fixing member 2 is stronger than before bottoming out. Thus, the main bending process of this embodiment can be said to include a final pressing process that fixes the flat plate portion 81 with a fixing force greater than the fixing force at the start.

[0050] (others) The present invention is not limited to the above embodiments. For example, the press forming apparatus 1 can be configured even if it is placed upside down. Furthermore, the technology of this disclosure can be applied to target shapes other than those described above (e.g., hat shapes). Also, the forming side surface does not have to have a concave cross-section. For example, the forming side surface may consist of a pressing surface and a straight cross-section that is bent relative to the pressing surface. In other words, the forming side surface may be concave in an L-shape, as shown in Figure 8. With such a configuration, the curved portion of the pre-bent section is not trapped, and the curved portion can be formed as it is formed. With this, for example, the curvature of the curved portion can be adjusted by adjusting the compression allowance (amount of compression) of the pre-bent section 82.

[0051] Furthermore, according to the technology of this disclosure, the curved portion of the pre-bent section (shoulder radius 92 of the molded product 9) can be thickened. By bending the pre-bent section while applying compressive force to the tip surface and shortening the plate length of the pre-bent section by the amount of compression, the plate thickness of the curved section can be increased in particular. By forming the molded product using a pre-molded product and molding member that account for the amount of thickness increase, a molded product with a thickened curved section can be formed. The curved section tends to be weaker than other parts in terms of strength and is often subject to reinforcement treatment after molding. However, according to the technology of this disclosure, the rigidity of the curved section can be increased by thickening, thereby improving its strength, and thus it becomes possible to omit, for example, reinforcement treatment of the curved section. The amount of thickness increase can be adjusted, for example, by the amount of compression (compression allowance). Thus, the fixing part and molding member may be configured to allow the thickness increase of the curved portion of the pre-bent section in this bending process. For example, the width of the clamping between the molding surfaces may be increased by the amount of thickness increase relative to the molding surface of the curved section, or, for example, as shown in Figure 8, the curved section may be designed not to be clamped between the molding surfaces. The fixing member may fix the flat plate portion 81 so that it does not move relative to itself (the fixing member) during the main bending process (or the final pressing process). Each device, such as the press forming device 1 and the burring device 6, may be arranged upside down (inverted) compared to the arrangement shown in the drawing. In addition, the second drive unit 42 may move the fixing member 2 during the main bending process, or it may move both the fixing member 2 and the forming member 3. For example, if the pre-bent portion is formed on only one side, or if one side is bent at a time, the fixing member may approach the forming member during the main bending process. [Explanation of Symbols]

[0052] 1...Press forming apparatus, 2...Fixing member, 2a...Fixing side, 3...Forming member, 3a...Forming side, 3b...Pre-forming surface, 3c...Pre-forming surface, 41...First drive unit, 42...Second drive unit.

Claims

1. A fixing member having a fixing side surface shaped according to the target shape of the plate-shaped member, and fixing the plate-shaped member, A molding member having a molding side surface and a pressing surface shaped according to the target shape, and a pre-molding surface, A first drive unit that moves the fixing member and / or the molding member in a predetermined direction, A second drive unit that moves the fixing member and / or the molding member in a direction intersecting the predetermined direction, A press forming method using a press forming apparatus equipped with, A pre-bending step is performed in which, with the plate-shaped member fixed by the fixing member and with the edge of the plate-shaped member in contact with the pre-molding surface, the molding member and / or the fixing member are moved in the predetermined direction by the first drive unit, the plate-shaped member is bent to one side in the predetermined direction to form a pre-bent portion at the edge of the plate-shaped member, and the pre-bent portion is positioned between the molding side surface and the fixing side surface, With the plate-shaped member fixed by the fixing member, the second drive unit brings the molding member and the fixing member closer together, and the tip surface of the pre-bent portion is brought into contact with the pressing surface so that the tip surface of the pre-bent portion is pressed, and the pre-bent portion is bent, and the bent pre-bent portion is sandwiched between the fixing side surface and the molding side surface in this bending process, Includes, The pressing surface is the other end face in the predetermined direction of a projection that protrudes from one end of the molded side surface in the predetermined direction toward the fixing member. Press forming method.

2. A fixing member having a fixing side surface shaped according to the target shape of the plate-shaped member, and fixing the plate-shaped member, A molding member having a molding side surface and a pressing surface shaped according to the target shape, and a pre-molding surface, A first drive unit that moves the fixing member and / or the molding member in a predetermined direction, A second drive unit that moves the fixing member and / or the molding member in a direction intersecting the predetermined direction, A press forming method using a press forming apparatus equipped with, A pre-bending step is performed in which, with the plate-shaped member fixed by the fixing member and with the edge of the plate-shaped member in contact with the pre-molding surface, the molding member and / or the fixing member are moved in the predetermined direction by the first drive unit, the plate-shaped member is bent to one side in the predetermined direction to form a pre-bent portion at the edge of the plate-shaped member, and the pre-bent portion is positioned between the molding side surface and the fixing side surface, With the plate-shaped member fixed by the fixing member, the second drive unit brings the molding member and the fixing member closer together, and the tip surface of the pre-bent portion is brought into contact with the pressing surface so that the tip surface of the pre-bent portion is pressed, and the pre-bent portion is bent, and the bent pre-bent portion is sandwiched between the fixing side surface and the molding side surface in this bending process, Includes, The fixed side surface is provided with a convex portion in cross-section corresponding to the shape of the curved portion of the target shape, The molded side surface has a cross-sectional concave portion that corresponds to the shape of the curved portion of the target shape and corresponds to the cross-sectional convex portion, In the bending process described above, the base portion of the pre-bent portion is sandwiched between the convex portion and the concave portion of the cross-section in a press molding method.

3. The pre-molded surface is formed at the corner of the molded member and is located on the plate-shaped member side of the molded side before the pre-bending process. The press molding method according to claim 2.

4. The fixing member and the molding member are configured to allow for increased thickness in the curved portion of the pre-bent section that occurs during the main bending process. The press molding method according to claim 2.

5. The pressing surface is located at the end of the molded side surface, on the end furthest from the plate-like member before the preliminary bending process. The press molding method according to any one of claims 2 to 4.

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