JP3546718B2 - Press molding method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a press forming method, and more particularly to a method of forming a work from a flat material into a final formed product having a U-shaped section having a substantially U-shaped cross section.
[0002]
[Prior art]
Conventionally, a press-formed product having a U-shaped portion having a substantially U-shaped cross section has been known. For example, in the suspension arm having the shape shown in FIG. 5, a portion X shown in FIG. 6, which is an AA section, and a portion Y shown in FIG. 7, which is a BB section, are both press-formed in a U-shape. . As a method of press-forming the X and Y portions having a substantially U-shaped cross section, for example, there is the following method.
▲ 1 ▼ X part
As shown in FIG. 8, it is formed by the steps shown in (a) to (c).
(A) One bending step in which a work w in the form of a plate-like material is sandwiched between one bending pad 12 and one bending punch 11 with its end protruding, and one bending die 13 is lowered to bend the end of the work.
(B) The work obtained in the step (a) is sandwiched between the two bending pads 22 and the two bending punches 21 with the ends protruding, and the two bending dies 23 having the slopes 23b are lowered to move the ends of the work. 2 bending process to bend.
(C) The work obtained in the step (b) is sandwiched between the three bending pads 32 'and the three bending punches 31'. Since the width of the three-bending punch 31 'is smaller than the width of the work, and the width of the three-bend pad 32' is substantially the same as the width of the work, the bent part r 'formed in the step (b) has three bent pads. 32 'is located substantially immediately below the left and right ends. In this state, a final bending step of lowering the three bending dies 33 'from above the work toward the work to make the end of the work U-shaped.
▲ 2 ▼ Y part
As shown in FIG. 9, it is formed by the steps shown in (a) to (d).
(A) A pilot hole punching step of punching a hole with a punch 62 in a flat work.
(B) A burring step of forming the flange P7 by bending the peripheral edge of the hole at a right angle with the burring punch 72 with respect to the flat plate portion P8 ".
(C) A preliminary bending step in which the flat plate portion P8 "is bent so as to form an acute angle with the flange portion P7 to form the inclined portion P8 '.
(D) A final bending step in which the work is bent by lowering the die 83 'to form a U-shape.
[0003]
[Problems to be solved by the invention]
However, the conventional methods for forming the X and Y portions having a U-shaped cross section have the following problems.
{Circle around (1)} In the final bending step of forming the X portion (c), the bending process is performed by the three-bending die 33 ′ in a state where the gap C1 is formed between the three-bending punch 31 ′ and the bending part r ′ of the work. Therefore, as shown by a dashed line in FIG. 8C, the U-shaped shape is broken due to the broken shape of the curved portion r ′, and the desired shape and dimensions cannot be secured.
{Circle around (2)} In the final bending step of forming the Y portion (d), the die descends while the gap C2 is still formed in the work, so that the displacement of the material is reduced as shown in FIG. 9 (d '). As a result, a desired U-shape cannot be secured, and a deviation occurs in the height of the flange P7.
An object of the present invention is to provide a press forming method capable of forming a work having a U-shaped portion having a desired shape and dimensions and a substantially U-shaped cross section.
[0004]
[Means for Solving the Problems]
The present invention that achieves the above object is as follows.
( 1 A press forming method for forming a workpiece from a state of a flat plate material into a final molded product having a U-shaped section having a substantially U-shaped cross section through a plurality of bending steps,
1 bending step of bending the end of the work in the state of the flat material to form a first intermediate product having a front flange portion;
The workpiece in the stage of the first intermediate product is bent at a portion separated from the front end flange portion, and is bent with respect to the flat plate portion, the vertical wall portion bent to the flat plate portion, and the vertical wall portion. A second bending step of forming a second intermediate product including the tip flange portion;
A holding surface having a substantially L-shaped cross section having a first surface extending in a direction of relative movement between the die and the workpiece and a second surface substantially perpendicular to the first surface; and the first surface of the holding surface A dice having an inclined surface connected to an end of the second surface and extending inclining with respect to the relative movement direction, and a parallel surface connected to an end of the second surface and extending in the relative movement direction. Run, The flat part of the work at the stage of the second intermediate product is held by a mold surface facing the second surface of the die and a mold surface parallel to the mold surface, and the tip flange portion and the vertical A first bent portion, which is a connection portion with a wall portion, is brought into contact with the inclined surface of the die, and the die and the work are relatively moved to move the first bent portion of the work. The inclined wall of the die is moved toward the holding surface of the die, and the vertical wall portion of the work and the first bent portion and the second bent portion of each end of the vertical wall portion are moved to the second bent portion of the die. Pressing between the surface and the mold surface facing the same, and forming a final molded product having a U-shaped portion having a substantially U-shaped cross section,
Having , Less molding method.
( 2 In the two bending step, the second bending punch having an upper surface, an inclined surface connected to an end of the upper surface and extending at an obtuse angle with respect to the upper surface, and a vertical surface connected to an end of the inclined surface and extending downward is formed by the second bending punch. (1) a workpiece in a stage of an intermediate product is disposed with an end protruding, the workpiece is held by the upper surface and a mold surface facing the upper surface, and (2) an inclined surface extending parallel to an inclined surface of the bending punch; The work is moved relative to a two-bending die having a vertical surface connected to the end of the inclined surface and extending in parallel with the vertical surface of the two-bending punch, and the work is moved by the two-bending punch and the two-bending die. The second intermediate product which is constrained and formed to have a flat plate portion, a vertical wall portion bent at an obtuse angle to the flat plate portion, and a tip flange portion bent at an obtuse angle to the vertical wall portion. 1 The press molding method as described.
( 3 A press forming method for forming a workpiece from a state of a flat plate material into a final molded product having a U-shaped section having a substantially U-shaped cross section through a plurality of bending steps,
Forming a first intermediate product having a plate-shaped portion provided with holes by drilling holes in the work in the state of the plate-shaped material;
The periphery of the hole of the first intermediate product is bent at a substantially right angle to the flat portion to form a flange, and a part of the flat portion around the flange is preliminarily formed so as to form an acute angle with the flange. An intermediate bending step of bending and forming a second intermediate product having the flange portion and an inclined portion forming an acute angle with the flange portion;
A holding surface having a substantially L-shaped cross section having a first surface extending in a direction of relative movement between the die and the workpiece and a second surface substantially perpendicular to the first surface; and the first surface of the holding surface A dice having an inclined surface connected to an end of the second surface and extending inclining with respect to the relative movement direction, and a parallel surface connected to an end of the second surface and extending in the relative movement direction. Run, Between a projecting surface of a die having a projecting surface protruding on the holding surface side of the die and extending along the parallel surface of the die and extending parallel to the parallel surface of the die, and the inclined surface of the die; Aligning the flange portion and the inclined portion of the workpiece in the state of the second intermediate product with the mold having the protruding surface, and aligning the edge of the inclined portion with the inclined surface of the die. The die and the workpiece are moved relative to each other with the connecting portion between the flange portion and the inclined portion being in contact with the mold surface of the die facing the second surface of the holding surface of the die. Moving the edge of the inclined portion from the inclined surface of the die toward the first surface of the holding surface of the die, and then moving the edge along the first surface of the holding surface to a second surface. To move the inclined portion along the mold surface facing the second surface of the holding surface. And Bill portion, a first surface portion extending along the holding surface is formed into a final molded article having a U-shaped portion of the substantially U-shaped cross section, and the final bending step,
The press molding method according to claim 1, comprising:
[0005]
The above (1) , (3) In the press forming method of (1), a holding surface having a substantially L-shaped cross section having a first surface extending in the direction of relative movement between the die and the work, and a second surface orthogonal to the first surface; And a parallel surface connected to the end of the second surface of the holding surface and extending in the direction of relative movement, and a parallel surface connected to the end of the second surface of the holding surface and extending in the direction of relative movement. By performing the final bending step using the same, it is possible to press-mold a final bent product having a U-shaped portion having a desired shape and dimensions and a substantially U-shaped cross section.
the above( 1 In the press forming method of the first aspect, in the final bending step, the flat plate portion of the work in the stage of the second intermediate product including the flat plate portion, the vertical wall portion, and the front end flange portion faces the second surface of the die. Surface and a mold surface parallel to the mold surface, the first bent portion of the work comes into contact with the inclined surface of the die, and the die and the work move relative to each other so that the first bent portion is inclined by the die. Move from the surface to the holding surface. Since the force exerted on the work by the inclined surface of the die is applied to the mold surface facing the second surface of the die, the shape of the second bent portion of the work is not impaired. Further, the work is pressed between the vertical wall portion and the first bent portion and the second bent portion at each end thereof between the second surface of the die and the mold surface opposed thereto. Therefore, a compressive stress is applied to the work, and the work is frozen in a shape in which the first bent portion and the second bent portion are pressed between the second surface of the die and the mold surface facing the die. Therefore, the shape of the second bent portion is not impaired, and it can be formed into a final bent product having a U-shaped portion having a desired shape and dimensions and a substantially U-shaped cross section.
the above( 2 In the press forming method of (1), the workpiece in the stage of the first intermediate product is constrained by the two-bending punch and the two-bending die in the two-bending step, and is bent at an obtuse angle to the flat part and the flat part. It is formed into a second intermediate product having a wall portion and a tip flange portion bent at an obtuse angle to the vertical wall portion. Since the work of the second intermediate product is formed by being restrained by the two-bending punch and the two-bending die, the bending shape is stable, and the tip flange does not extend after the two-bending process.
the above( 3 In the press forming method of the first aspect, in the final bending step, the flange portion of the workpiece at the stage of the second intermediate product extends along the projecting surface of the mold having the projecting surface projecting toward the holding surface side of the die, and the end of the inclined portion of the work is formed. The die and the workpiece move relative to each other while the edge is in contact with the inclined surface of the die and the connection between the flange portion and the inclined portion of the workpiece is in contact with the mold surface facing the second surface of the die, and the end of the inclined portion Since the edge moves from the inclined surface of the die to the first surface of the holding surface of the die, compressive stress is applied to the inclined portion, and the inclined portion is moved along the first surface of the holding surface of the die along the second surface. And the workpiece is bent into a portion extending along the mold surface facing the second surface of the die and a portion extending along the first surface, so that the workpiece can be moved from the state of the flat plate material to a desired shape. It can be formed into a final molded product having a U-shaped portion having a U-shaped cross section in shape and size.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show a first embodiment of the present invention, FIG. 3 shows a second embodiment of the present invention, and FIG. 4 shows a third embodiment of the present invention.
[0007]
The press forming method and operation of the first embodiment of the present invention will be described with reference to FIG. In the first embodiment of the present invention, a method of forming a U-shape in the X portion on one side of the suspension arm shown in FIG. 6 through the steps of 1 bend, 2 bends, and 3 bends (final bend) will be described. The upper part of FIG. 1 shows the start of processing, and the lower part shows the end of processing.
[0008]
First, one bending process will be described. At the start of the one bending step, as shown in FIG. 1A, the flat part of the work W0 in the state of the flat material is placed on a fixed one bending punch 11 having a horizontally extending upper surface 11a. Then, the one bending pad 12 having the mold surface 12a facing the upper surface 11a of the one bending punch 11 is lowered from above, and the work W0 is held between the one bending punch 11 and the one bending pad 12. The width of the work W0 is longer than the width of the single bending pad 12 and the single bending punch 11, and the end of the work W0 protrudes from the single bending pad 12 and the single bending punch 11 in the left-right direction. The one bending pad 12 is longer than the one bending punch 11 by the same length as the plate thickness t of the work W0 with respect to the width of the one bending punch 11. The one bending die 13 has a parallel surface 13b parallel to a side surface 12b orthogonal to the mold surface 12a, and the parallel surface 13b contacts the side surface 12b to lower the one bending die 13 disposed above the work. Between the parallel surface 13b of the one-bending die 13 and the side surface 11b of the one-bending punch 11, there is a gap substantially equal to the plate thickness t of the work W0.
Since the one-bending die 13 keeps descending even after coming into contact with the end P1 'of the work W0 protruding left and right from the one-bending pad 12 and the one-bending punch 11, the work W0 has a P1' part at the one-bending punch 11. And the front end flange portion P1 is formed. The first bent portion r1, which is a connecting portion between the flat portion of the flat material and the front flange portion P1, is substantially perpendicular. The work W0, which was in the state of a flat material at the start of the one bending step, has a first intermediate part having a flat part and a front end flange part P1 whose both ends are bent by the one bending punch 13 at the completion of the one bending step. Product W1.
[0009]
Next, the two bending steps will be described. At the start of the two-bending step, as shown in FIG. 1B, the first intermediate product W1 is placed on a fixed two-bending punch 21 having a horizontally extending upper surface 21a. Then, the two-bend pad 22 having the mold surface 22a facing the upper surface 21a of the two-bend punch 21 is lowered from above, and the first intermediate product W1 is held between the two-bend punch 21 and the two-bend pad 22. Since the width of the first intermediate product W1 is longer than the widths of the two bending pads 22 and the two bending punches 21, the first intermediate product W1 is a part P2 of the flat plate portion in the left-right direction from the two bending pads 22 and the two bending punches 21, respectively. The width of the two-bend pad 22 is smaller than the width of the two-bend punch 21.
Then, the two bending dies 23 arranged above the first intermediate product W1 are lowered. The two-bending die 23 has a parallel surface 23a parallel to a side surface 22b orthogonal to the lower surface 22a of the two-bending pad 22, and an inclined surface 23b connected to the parallel surface 23a and extending in a direction away from the side surface 22b of the two-bending pad 22. And a lower surface 23c connected to the inclined surface 23b and extending horizontally. The connecting portion between the parallel surface 23a and the inclined surface 23b is curved.
As the two-bending die 23 descends, first, the lower surface 23c of the two-bending die 23 comes into contact with a part P2 ″ of the flat plate portion of the first intermediate product W1. Part P2 ″ of the shape is bent starting from the corner 21r of the two-bending punch 21.
The two-bending die 23 descends until the connection between the parallel surface 23a and the inclined surface 23b of the two-bending die 23 is located on substantially the same plane as the mold surface 22a of the two-bending pad 22. At this time, the edge of the front end flange portion P1 is in contact with the double bending punch 21. A part P2 ″ of the flat plate portion of the work is bent by the two bending dies 23 to become a vertical wall part P2 ′ along the inclined surface 23b of the two bending dies 23. Between the two bending pads 22 and the two bending punches 21 The second bent portion r2, which is a connection portion between the flat plate portion P3 and the vertical wall portion P2 'held at the above, has an obtuse angle.
At the completion of the second bending step, the first intermediate product having the distal flange portion P1 has a flat plate portion P3, a vertical wall portion P2 'forming an obtuse angle with the flat plate portion P3, and a second intermediate product having the distal flange portion P1. It becomes an intermediate product W2.
[0010]
Next, the three bending steps (final bending step) will be described. At the start of the third bending step, as shown in FIG. 1 (c), the second intermediate product W2 having the vertical wall portion P2 'formed in the second bending step is vertically moved by a spring force or the like having an upper surface 31a extending horizontally. The end is protruded and placed on the three-bending floating punch 31 movable in the direction (direction of relative movement between the work and the die). The protruding length is substantially the same as the length of the front end flange portion P1 of the second intermediate product W2.
Then, the three-bend pad 32 having the mold surface 32a facing the upper surface 31a of the three-bend floating punch 31 is lowered from above, and the second intermediate product W2 is held between the three-bend floating punch 31 and the three-bend pad 32. The width of the third bending pad 32 is substantially the same as the length of the flat plate portion P3 of the second intermediate product. A fixed three-bending die 33 is disposed below the second intermediate product W2, which holds the flat plate portion P3 of the second intermediate product W2 with the three-bending floating punch 31 and the three-bending pad 32.
The 3-bending die 33 includes a holding surface 33L having a substantially L-shaped cross section having a first surface 33a extending in the direction of relative movement with the second intermediate product W2 and a second surface 33b orthogonal to the first surface 33a. An inclined surface 33c connected to an end of the first surface 33a and extending at an angle of θ2 with respect to the relative movement direction, and a parallel surface connected to an end of the second surface 33b and extended in the relative movement direction. And a surface 33d. The inclined surface 33c is inclined in a direction away from the parallel surface 33d.
Then, the second intermediate product W2 is lowered while being held between the 3-bending floating punch 31 and the 3-bending pad 32. By the lowering of the second intermediate product W2, first, the first bent portion r1, which is the connection portion between the front flange portion P1 and the vertical wall portion P2, comes into contact with the inclined surface 33c of the three-bending die 33. The forming angle θ3 between the first bent portion r1 and the inclined surface 33c of the three-bending die 33 is such that the second intermediate product W2 is lowered with respect to the die 33, and the first bent portion r1 is formed by the inclined surface of the three-bending die 33. It becomes smaller as it moves from 33c toward the holding surface 33L.
[0011]
In order to enhance the processing accuracy, the forming angle θ3 is desirably 45 ° or less when the first bent portion r1 of the work W2 comes into contact with the inclined surface 33c of the three-bending die 33.
[0012]
When it is necessary to reduce the height of the three bending dies 33 depending on the condition of the arrangement space of the equipment, when the first bent part r1 and the inclined surface 33c of the three bending dies 33 start to contact each other, θ3 May be set to 45 ° or less, and the inclined surface 33c of the three-bending die 33 may be curved as shown in FIG.
[0013]
When the second intermediate product W2 descends in a state where the first bent portion r1 is in contact with the inclined surface of the three-bending die 33, the force from the three-bending die 33 acts on the flat plate portion P3. Since the force is received by the three bending pads 32, the shape of the second bent portion r2 is not damaged unlike the conventional shape shown by the dashed line in FIG. 8C.
When the tip flange portion P1 reaches the second surface 33b of the three-bending die 33 due to the lowering of the second intermediate product W2, the vertical wall portion P2 'of the second intermediate product W2, the first bent portion r1, and the second bent portion. The portion r2 is pressed between the second surface 33b of the three-bending die 33 and the mold surface 32a of the three-bending pad 32 opposed thereto, and the shape is fixed to complete the three-bending process. Since the vertical wall portion P2 'of the second intermediate product is along the first surface 33a of the three-bending die 33, it has a shape extending in parallel with the first surface 33a. Therefore, the second bent portion r2 is substantially at a right angle when the three bending steps are completed.
[0014]
The workpiece is press-molded into a final molded product W3 having a highly accurate U-shaped part having both ends at a desired shape and dimensions by obtaining one to three bending steps from the stage of the flat material. .
[0015]
In the first embodiment, in order to relatively move the work and the die, the die 33 is fixed in the three bending steps, and the work is moved with respect to the die. However, the reverse is also possible.
[0016]
Further, in the first embodiment, the mold used in the three bending process can be used as it is even in the case of processing a workpiece having a different plate thickness, so that the capital investment cost accompanying the change in the plate thickness increases. No problem.
[0017]
Further, when the machining in the three bending process is completed, the floating punch 31 is brought into contact with the end face of the front end flange portion P1 of the work, so that the end surface accuracy of the front end flange portion P1 can be improved.
[0018]
Next, a press forming method according to a second embodiment of the present invention and its operation will be described with reference to FIG. The second embodiment of the present invention is different from the first embodiment in the two bending steps. Since the method in the other steps is the same, the description is omitted, and the following describes the two bending steps which are different from the two bending steps of the first embodiment.
At the start of the two-bending process, as shown in FIG. 3B, the first intermediate product W1 is placed on a fixed two-bending punch 21 having a horizontally extending upper surface 21a. The two-bending punch 21 has an upper surface 21a, an inclined surface 21b connected to an end of the upper surface 21 and extending at an obtuse angle to the upper surface, and a vertical surface 21c connected to an end of the inclined surface and extending downward.
The two-bend pad 22 having the mold surface 22a facing the upper surface 21a of the two-bend punch 21 is lowered from above. Thereby, the first intermediate product W1 is held between the two bending punches 21 and the two bending pads 22. Since the width of the first intermediate product is longer than the widths of the two bending pads 22 and the two bending punches 21, the first intermediate product W1 is a part P2 ″ of the flat plate portion in the left-right direction from the two bending pads 22 and the second bending punch 21, respectively. The width of the two-bend pad 22 is smaller than the width of the two-bend punch 21.
Then, the two bending dies 23 arranged above the first intermediate product W1 are lowered. The two-bending die 23 includes a parallel surface 23a parallel to a side surface 22b orthogonal to the lower surface 22a of the two-bending pad 22, an inclined surface 23b connected to the parallel surface 23a and extending in parallel with the inclined surface 21b of the two-bending punch 21, and an inclined surface 23b. It has a vertical surface 23d connected to the end of the surface 23b and extending in parallel with the vertical surface 21c of the two-bending punch. The connecting portion between the parallel surface 23a and the inclined surface 23b is curved.
As the two-bending die 23 descends, first, the lower surface 23c of the two-bending die 23 comes into contact with a part P2 ″ of the flat portion of the first intermediate product. A part P2 ″ of the flat plate portion of W1 is bent starting from the corner 21r of the two-bend punch 21 to form a vertical wall portion P2 ′.
The two-bending die 23 is lowered until the connection between the parallel surface 23a and the inclined surface 23b of the two-bending die 23 is located on substantially the same plane as the mold surface 22a of the two-bending pad 22. The tip flange portion P1 is restrained by the vertical surface 21c of the two-bending punch 21 and the vertical surface 23d of the two-bending die 23. Further, the vertical wall portion P2 'is restrained by the inclined surface 21b of the two-bending punch 21 and the inclined surface 23b of the two-bending die 23. Therefore, the front flange portion P1 is bent back.
When the second bending process is completed, the first intermediate product W1 having the distal end flange portion P1 has an obtuse angle with respect to the flat plate portion P3 and the vertical wall portions P2 'and P2' which form an obtuse angle with the flat plate portion P3. A second intermediate product W2 having a front end flange portion P1 '.
[0019]
When forming a work having a stretch flange forming portion as shown in FIG. 5, as shown in the first embodiment, if the front flange portion P1 is formed in an unconstrained state in the two bending process, the front flange portion P1 is formed. May be extended and the bent shape of the first bent portion r1 may be lost. When the front flange portion P1 is extended, when performing the three bending process, the front end of the front flange portion P1 comes into contact from the inclined surface 33c of the three-bending die 33 to the second surface 33b, which may cause galling. However, in the second embodiment, the first actual shape of the two-bending punch 21 and the two-bending die 23 are used, and the front flange portion P1 is restrained by the two-bending punch 21 and the two-bending die 23 to perform the two-bending process. The tip flange portion P1 does not extend in the second bending process. Therefore, in the three bending process, contact between the three bending dies 33, particularly between the first surface and the second surface, and the front end of the front end flange portion of the work is avoided, and galling is prevented, and accuracy is easily ensured.
[0020]
Next, a press forming method according to a third embodiment of the present invention and its operation will be described with reference to FIG. In the third embodiment of the present invention, a method of forming a U-shape, particularly a Y portion, of a portion of the suspension arm shown in FIG.
[0021]
First, a pilot hole punching step is performed. A flat work is placed on a prepared hole die 61, and a prepared hole punch 62 is lowered from above toward the work, and a hole is formed in the work as shown in FIG.
[0022]
Next, a burring step is performed. The perforated work W11 (first intermediate product) is placed on the burring die 71, and the burring punch 72 is lowered from above toward the hole of the work W11, and as shown in FIG. The part is bent at a substantially right angle to the flat part of the work to form a work W12 having a flange P7.
Since the material of the work W12 is constrained by the burring punch 72 and the burring die 71, the inner diameter accuracy is ensured.
[0023]
Next, a preliminary bending step is performed. A part of the flat plate portion P8 ″ around the flange portion P7 of the work W12 is preliminarily bent so as to form an acute angle with the flange portion P7 to form a work W13 (second intermediate product) partially having an inclined portion P8 ′. I do.
[0024]
Next, a bending (final bending) step of forming a part of the work W13 into a U-shape is performed. Hereinafter, press forming of the work portion formed into the flange portion P7 and the inclined portion P8 'in the previous process will be described. The flat portion 8 "of the work W13, on which the inclined portion P8 'is not formed, is not bent in the final bending step of the third embodiment of the present invention.
First, the hole of the work W13 is inserted into the cored bar 81, and the bending pad 82 is lowered toward the bending die 83 disposed around a part of the cored bar 81.
The bending die 83 includes a first L-shaped holding surface 83L having a first surface 83a extending in the direction of relative movement with the workpiece W13 and a second surface 83b orthogonal to the first surface 83a. It has an inclined surface 83c connected to the end of the surface 83a and extending inclining with respect to the relative movement direction, and a parallel surface 83d connected to the end of the second surface 83b and extending in the relative movement direction. The inclined surface 83c is inclined in a direction away from the parallel surface 83d.
The metal core (mold having a protruding surface) 81 is arranged along the parallel surface 83d of the bending die 83, and has a protruding surface 81a protruding above the second surface 83b of the bending die 83.
The work W13 descends with the flange portion P7 along the protruding surface 81a of the cored bar 81 and the inclined portion P8 'with its edge contacting the inclined surface 83c of the bending die 83. The edge of the inclined portion P8 'of the work W13 moves from the inclined surface 83c of the bending die 83 toward the first surface 83a, and further moves to the second surface 83b, as shown in FIG. In addition, the inclined portion P8 'becomes a portion P8b extending along the mold surface 82a facing the second surface 83b of the bending die 83, and a portion extending along the portion P8a extending along the first surface 83a. Thereby, the workpiece is a U-shaped section having a substantially U-shape including a flange portion P7, a portion P8b extending along the mold surface 82a, and a portion P8a extending along the first surface 83a from the state of the flat material. It is molded into a final molded article having a part.
[0025]
In the final bending step, the hole of the work is inserted into the metal core 81, and the flange P7 is pressed against the protruding surface 81a of the metal core 81, so that the inner diameter accuracy of the work is made precise.
In the work W13, the edge of the inclined portion P8 'comes into contact with the inclined surface of the bending die 83, and compressive stress starts to be applied, and the edge of the workpiece W13 reaches the second surface 83b of the three-bending die 83 until the edge reaches the second surface 83b. Is finally bent, and finally a work having a U-shape including the flange portion P7 and P8b extending along the mold surface 82a and P8a extending along the first surface 83a is obtained. In the final bending step, since the flange P7 is not bent by the die, the processing that causes a deviation in the height is not performed. Therefore, a U-shaped portion having a desired shape and dimensions can be obtained.
[0026]
In the third embodiment, the bending die 83 is fixed and the workpiece is moved with respect to the die. However, the reverse is also possible.
[0027]
【The invention's effect】
Claim 1 , 3 According to the press forming method, the holding surface having a substantially L-shaped cross section having a first surface extending in the direction of relative movement between the die and the workpiece and a second surface orthogonal to the first surface; An inclined surface connected to an end of the first surface and extending obliquely to the relative movement direction; and a parallel surface connected to an end of the second surface of the holding surface and extended in the relative movement direction. By performing the final bending step using a die, it is possible to press-mold a final molded product having a desired shape and dimensions and a highly accurate U-shaped section having a substantially U-shaped cross section.
Claim 1 According to the press forming method of (1), in the final bending step, the flat portion of the work at the stage of the second intermediate product is held by the mold surface facing the second surface of the die and the mold surface parallel to the mold surface, The first bent portion of the work and the inclined surface of the die are brought into contact with each other, and the die and the work are relatively moved to move the first bent portion from the inclined surface of the die toward the holding surface. The force exerted by the inclined surface on the work is received by the mold surface facing the second surface of the die, and the work is not damaged by the shape of the second bent portion, and the first wall of the work and the first end of each end thereof are not damaged. Since the bent portion and the second bent portion are pressed between the second surface of the die and the mold surface facing the die, a compressive stress is applied to the work, and the work is provided with the bent portion bent into a desired shape. It can be formed in a substantially U-shaped cross section.
Claim 2 According to the press forming method of (1), the tip flange is restrained by the two-bending punch and the two-bending die in the two-bending step, so that the tip-flange can be prevented from being elongated.
Claim 3 According to the press forming method of (1), in the final bending step, the flange portion of the workpiece at the stage of the second intermediate product is made to follow the projecting surface of the mold having the projecting surface projecting toward the holding surface side of the die, and the end of the inclined portion The die and the workpiece are moved relative to each other while the edge is in contact with the inclined surface of the die, and the connection between the flange and the inclined portion is in contact with the mold surface facing the second surface of the die. Since the edge is moved from the inclined surface of the die to the first surface of the holding surface of the die, a compressive stress is applied to the workpiece, and further, the workpiece is moved to the second surface along the first surface of the holding surface of the die. A portion extending along the mold surface facing the second surface of the die holding surface and a portion extending along the first surface are formed, and the inclined portion is bent into a desired shape with a substantially U-shaped cross section. It can be formed into a final molded article having a U-shaped portion in a shape.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a press molding method according to a first embodiment of the present invention.
FIG. 2 is a view showing an example of a three-bending die according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a press molding method according to a second embodiment of the present invention.
FIG. 4 is a diagram illustrating a press molding method according to a third embodiment of the present invention.
FIG. 5 is a perspective view of a press-formed product according to all embodiments of the present invention.
FIG. 6 is a sectional view taken along line AA of FIG. 5;
FIG. 7 is a sectional view taken along line BB of FIG. 5;
FIG. 8 is a diagram illustrating a conventional press molding method.
FIG. 9 is a diagram illustrating a conventional press molding method.
[Explanation of symbols]
32a, 82a Mold surface facing the second surface of the die
33, 83 dice
33a, 83a First surface
33b, 83b Second surface
33c, 83c Inclined surface
33d, 83d parallel plane
33L, 83L Holding surface
P1 Tip flange
P2 Vertical wall
P3 flat part
r1 First bent part
r2 2nd bent part
P7 collar
P8 'slope
81 Mold with protruding surface
81a Projecting surface
W0 flat material
W1 First intermediate product
W2 Second intermediate product
W11 1st intermediate product
W13 Second intermediate product

Claims (3)

A press-forming method for forming a workpiece from a state of a flat material into a final molded product having a U-shaped portion having a substantially U-shaped cross section through a plurality of bending steps,
1 bending step of bending the end of the work in the state of the flat material to form a first intermediate product having a front flange portion;
The workpiece in the stage of the first intermediate product is bent at a portion separated from the front end flange portion, and is bent with respect to the flat plate portion, the vertical wall portion bent to the flat plate portion, and the vertical wall portion. A second bending step of forming a second intermediate product including the tip flange portion;
A holding surface having a substantially L-shaped cross section having a first surface extending in a direction of relative movement between the die and the workpiece and a second surface substantially perpendicular to the first surface; and the first surface of the holding surface A dice having an inclined surface connected to an end of the second surface and extending inclining with respect to the relative movement direction, and a parallel surface connected to an end of the second surface and extending in the relative movement direction. The flat part of the work being executed and being in the stage of the second intermediate product is held by a mold surface facing the second surface of the die and a mold surface parallel to the mold surface, and the tip flange portion is held. A first bent portion, which is a connecting portion between the first bent portion and the vertical wall portion, and the inclined surface of the die are brought into contact with each other, and the die and the work are relatively moved, so that the first bending of the work is performed. Part is moved from the inclined surface of the die toward the holding surface of the die, and then the The vertical wall portion of the mold and the first bent portion and the second bent portion at each end thereof are pressed between the second surface of the die and the mold surface facing the die, and have a substantially U-shaped cross section. Final bending step of forming into a final molded article having a U-shaped portion,
The has, up less molding method. In the two bending step, a first bending punch having an upper surface, an inclined surface connected to an end of the upper surface and extending at an obtuse angle with respect to the upper surface, and a vertical surface connected to an end of the inclined surface and extending downward is provided. A workpiece in a stage of an intermediate product is disposed with an end protruding, and the workpiece is held by the upper surface and a mold surface facing the upper surface, and a slope extending parallel to a slope of the two-bending punch and the slope. The work is moved relative to a two-bending die having a vertical surface connected to an end of a surface and extending in parallel with the vertical surface of the two-bending punch, and the work is restrained by the two-bending punch and the two-bending die. forming a second intermediate product having a distal flange portion which is bent at an obtuse angle with respect to the said longitudinal wall portion bent vertical wall portion at an obtuse angle relative to flat portion and the flat plate-like portion with claim 1 The press molding method as described. A press-forming method for forming a workpiece from a state of a flat material into a final molded product having a U-shaped portion having a substantially U-shaped cross section through a plurality of bending steps,
Forming a first intermediate product having a plate-shaped portion provided with holes by drilling holes in the work in the state of the plate-shaped material;
The periphery of the hole of the first intermediate product is bent at a substantially right angle to the flat portion to form a flange, and a part of the flat portion around the flange is preliminarily formed so as to form an acute angle with the flange. An intermediate bending step of bending and forming a second intermediate product having the flange portion and an inclined portion forming an acute angle with the flange portion;
A holding surface having a substantially L-shaped cross section having a first surface extending in a direction of relative movement between the die and the workpiece and a second surface substantially perpendicular to the first surface; and the first surface of the holding surface A dice having an inclined surface connected to an end of the second surface and extending inclining with respect to the relative movement direction, and a parallel surface connected to an end of the second surface and extending in the relative movement direction. The die has a projecting surface, which is arranged along the parallel surface of the die and extends parallel to the parallel surface of the die, and has a projecting surface protruding toward the holding surface of the die, and the inclined surface of the die. In the meantime, the flange portion and the inclined portion of the workpiece in the state of the second intermediate product are aligned with the mold having the protruding surface with the flange portion, and the edge of the inclined portion is set in the die. Arranged in contact with the inclined surface, the connecting portion between the flange portion and the inclined portion is provided on the holding surface of the die. The die and the work are relatively moved while being kept in contact with the mold surface facing the surface of No. 2 to move the edge of the inclined portion from the inclined surface of the die to the first surface of the holding surface of the die. A portion extending along a mold surface opposed to the second surface of the holding surface, wherein the inclined portion is moved to a second surface along the first surface of the holding surface; Forming a portion extending along the first surface of the holding surface, and forming a final molded product having a U-shaped portion having a substantially U-shaped cross section;
The press molding method according to claim 1, comprising:

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