JPH10277656A - Press forming die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press forming die which produces an article without generating fault of deformation or crack on a root of a collar of a metal sheet with a flange collar piercing hole. SOLUTION: A die 36 is composed of an inside hollow member 35 having a hole to be driven with a punch 33 and a die lifter plate 34 (outside hollow member) attached outside the inside hollow member 35. An annular projection 35a is formed on the opening end face of the inside hollow member 35 along the internal circumference edge. This annular projection 35a prevents the collar root 43a from biting in a guide hole 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-forming die for forming a collar on the top of a collar erected on a plate material to be processed.

[0002]

2. Description of the Related Art A plate material to be processed such as a metal plate is processed into various shapes by press molding and used. FIG. 5 is a cross-sectional view showing an example of a press-formed product. A circular through-hole 2 is formed in a metal plate 1, a collar 3 is provided on the periphery of the through-hole 2, and a top portion of the collar 3 is further provided. A flange portion 4 facing outward is formed at the outside.

[0003] The through-hole 2 provided with the collar 3 with the collar 4
BACKGROUND ART An aluminum plate having a plurality of (hereinafter sometimes referred to as a through-hole with a collar) is used as a heat-dissipating cooling plate fin of a heat exchanger in, for example, a car cooler or a home cooler.

FIG. 6 is a cross-sectional view for explaining an example of a process for manufacturing a metal plate having the above-mentioned flanged collar-equipped through-hole (hereinafter, this may be referred to as a flanged collar-equipped metal plate). .

[0005] First, a metal plate 1 is sandwiched between a burring die 12 having through holes aligned with a burring stopper 13. Next, by punching up the piercing punch 10, a small hole having an opening diameter smaller than that of the through-hole with a collar to be formed is drilled in the metal plate 1, and subsequently, the piercing burring punch 11 is pushed up to return to the periphery of the small hole. (Projecting piece 23) is further protruded (FIG. 6 (a)).
). Next, the projecting piece 23 is centered between the ironing die 14 and the ironing stopper 15 in which the through-holes are aligned, and the metal plate 1 is sandwiched. The collar 3 is extended (ironed) to form a collar 3 (FIG. 6 (b)).

[0006] Thereafter, the metal plate 1 with the collar is placed in alignment with the refrea die 17, and the small diameter portion 18 b of the refrea punch 18 is attached to the through hole 2 of the metal plate 1 and the refrea die 17.
The top of the collar 3 is bent outward by the stepped portion 18a of the refrea punch 18 while being pushed down from above so as to be inserted into the guide hole 19 of FIG. )).

In addition to the above-described manufacturing method, as shown in Japanese Patent Application Laid-Open No. 4-165295, the tip of the formed projecting piece 23 is curved, and pressure is applied to the curved portion from the side to form a laminated state. Then, an ironing process and a reflaring process are performed in the same manner as described above.

[0008]

However, the above-mentioned metal plate with a flange collar through hole manufactured as described above has a problem that the root 3a of the collar 3 sometimes deforms or cracks. This is because a gap 19a formed between the small-diameter portion 18b of the punch and the guide hole 19 during the refrea processing is used.
The reason is considered to be that the base 3a of the collar bites into the surface (see FIG. 6C). This biting is caused by the unevenness of the ironing process in the ironing process.
It often occurs when it is present in a location. In particular, in the case of performing a press working to give a small shape such as the flange portion 4 to a thin plate material to be processed, defects such as the deformation and cracks often occur. The present invention has been made in view of the above problems, and an object of the present invention is to provide a press molding die capable of manufacturing a defect-free product.

[0009]

According to the present invention, a plate material to be processed having a collar provided on the periphery of a through hole is held on a supporting surface of a die, and a punch is inserted into a hollow portion of the collar from the top side of the collar. In a press-molding die for operating the die and / or the punch to drive and forming a flange at the top of the collar, the die includes an inner hollow member having a hole into which the punch is driven, and an inner hollow member. The gist of the invention is to have an outer hollow member which is externally provided on the member, and to have an annular projection on an opening end face of the inner hollow member along an inner peripheral edge thereof.

As described above, in the present invention, since the annular projection is provided on the opening end surface of the inner hollow member, the collar base of the plate material to be processed abuts against the annular projection to receive resistance, and the die guide hole (the inner hollow member of the inner hollow member) is received. It is possible to prevent the base of the collar from biting into the opening, and as a result, it is possible to manufacture a product in which the base of the collar has no deformation, crack, or the like.

When the die is formed by one member and an annular projection is provided on the end face of the guide hole, the penetration of the base of the collar can be prevented. However, the die is formed by one member. It is difficult to process into such a shape.

That is, for example, FIG. 7 is a perspective view showing a die 20 having five guide holes 29. The die 20 is formed of one member, and an annular projection 21 is formed on an end face of the guide hole 29.
Is provided. As a processing to such a shape, for example, a method of cutting a flat part 22 serving as an upper surface of a die while leaving a part of the annular projection 21 can be considered, but it is very difficult to finish such processing precisely. Accompanied by

However, in the present invention, as described above, the die is composed of a plurality of members, one of which is an inner hollow member, and the other is an outer hollow member into which the inner hollow member can be inserted. Therefore, in manufacturing the die, if the inner hollow member and the outer hollow member are separately formed and then combined, a fine shape such as the annular protrusion can be easily formed.

Furthermore, in the press-molding die according to the present invention, it is preferable that the annular projection has a flared curved surface formed at the outer peripheral side root. When the curved surface portion is formed in this way, the base of the collar of the plate material to be processed follows the above-mentioned annular projection of the die, and comes into contact with not the point but the surface. There is no fear of wearing, and the bite prevention resistance is more firmly exhibited. It is most preferable that the curved surface portion has the same curvature as the roundness of the outer side surface of the base of the collar of the plate material to be processed, because the annular projection and the base of the collar are exactly along.

[0015] In addition, in the present invention, the punch has a large-diameter portion and a small-diameter portion driven into the hollow portion of the collar, and a transition shoulder from the large-diameter portion to the small-diameter portion has a flange. A step portion for use, wherein the punch has a core member and an outer member provided outside the core member, and a bonding interface between the core member and the outer member is the flange forming step portion. Is preferred.

In the conventional press forming die, when the finishing accuracy of the step 18a of the refrea punch 18 is poor, the pressure applied to the collar 3 of the plate material to be processed is increased by the collar base 3a.
As described above, there is a case where a bite may enter the gap 19a between the small-diameter portion 18b and the guide hole 19 as described above (see FIG. 6C). Also, as described above, the step 18
There is also a problem that the flange is deformed when the finishing accuracy of a is poor.

However, in the present invention, the punch is composed of two or more members such as a core member and an outer member, and the joint interface portion is formed as a flange forming step, so that the flange forming step is divided. Therefore, the processing of the step for forming the flange is facilitated, so that the finishing accuracy is improved. As a result, the deformation of the flange as described above, the deformation of the base of the collar due to the penetration into the gap 19a, and the like are performed. Does not occur.

Further, in the present invention, it is more preferable that the step portion for forming the flange is U-shaped, and since the shape of the U-shaped portion is like this, the thickness of the top of the collar at the time of refrea processing is improved. As a result, the collar does not deform. In addition, since the punch is composed of a plurality of members as described above, even if the flange forming step has a special shape such as a U-shaped groove, each member is separately formed and then combined with each other. , Can be formed in the special shape described above.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (a) is a sectional view showing a state in which a metal plate with a collar collar is manufactured using a press mold according to one embodiment of the present invention. It is. The punch 33 is composed of a cylindrical punch core member 31 and a cylindrical punch outer member 32, and these two members are joined to form a large diameter portion (shown by B in the drawing) and a small diameter portion (shown in the drawing). A indicated by A), and the shoulder portion from the large-diameter portion to the small-diameter portion is a flange forming step 37. The die 36 is composed of two members: a cylindrical die inner hollow member 35 and a die lifter plate (outer hollow member) 34 having a hole for inserting the die inner hollow member 35. A metal plate 41 is placed on the die 36. A punch frame member 38 is shown around the punch 33.

FIG. 1B is an enlarged cross-sectional view of a portion surrounded by a circle at the punch 33 in FIG. 1A. The flange forming step 37 of the punch 33 is U-shaped as shown in the figure, and the flange forming step 37 is formed at the joint interface between the punch core member 31 and the punch outer member 32. ing.

FIG. 1C is an enlarged sectional view of the circled portion at the die 36 and the metal plate 41 in FIG. 1A. At the periphery of the opening (guide hole 39) of the inner hollow member 35 of the die 36, the die upper surface (flat portion 35b)
A raised annular projection 35a is provided. The top of the annular projection 35a is a flat surface (top surface 35c), and the outer peripheral side root portion 35d from the end of the top surface 35c.
The shape is such that a curved surface portion is formed in a skirt spread toward.

FIG. 2 is a cross-sectional view for explaining the curvature of the curved surface portion. As can be seen from FIG. 2, the curved surface portion of the annular projection is an imaginary extension thereof (shown by a dashed line in FIG. 2). Is continuous with the side outer wall 31a of the small diameter portion (portion into the collar hollow portion) of the punch 33, whereby the curved surface portion of the annular projection has substantially the same curvature as the outer side surface of the collar base of the plate material to be processed. As shown.

It is extremely difficult to process and form a punch or a die having such a shape from an integrated material. However, since the punch and the die are each composed of two members as described above, the processing is performed for each member. By combining them thereafter, they can be easily formed into a desired shape as a whole.

That is, in manufacturing the die, FIG.
As shown in the perspective view of (a), by cutting the opening end face of the inner hollow member 35 so as to form a flat portion 35b on the upper surface of the die while leaving the portion of the annular projection 35a, the annular projection 35a can be easily formed. Then, as shown in FIG. 4B, the inner hollow member 35 is attached to the die lifter plate 34.
, A die having an annular projection on the end face of each guide hole as a whole can be easily manufactured. In the present embodiment, the die inner hollow member 35 is fixed at a height position with high precision, but the die lifter plate 34 has a lifter function and can be moved up and down (press position / separation position movement). is there.

In manufacturing the punch 33, the punch core member 31 and the punch outer member 32 are separately processed to form approximately 1/4 arc shapes at the portions to be the step portions for forming the flange. The punch 33 is joined by sliding. Although it is difficult to form the U-groove shape integrally, it is easy to form the above-mentioned approximately 1/4 arc shape.
These can be combined to form a U-shaped flange-forming step.

In performing the refrea processing, a metal plate 41 on which a collar 43 is formed by performing an ironing process as in the above-mentioned conventional method (see FIGS. 6A and 6B) is used as a plate material to be processed. As shown in FIG.
Is placed on a die 36 and pressed by a punch 33 to form a U-shaped flange 44 on the top of the collar 43 (see FIG. 1). At this time, since the flange forming step 37 of the punch 33 has a U-shaped groove as described above, the top of the collar 43 bends along the U-shaped groove, and the flange 44 is formed without difficulty.

Further, at the time of pressing, the collar base 43a of the metal plate 42 comes into contact with the annular projection 35a of the inner hollow member 35 and does not bite into the guide hole 39. As a result, the metal plate 41 with a flange collar through-hole without deformation and cracking of the collar base 43a is obtained.

Further, since the die is a separate member, the height of the metal plate placed on the die can be adjusted by moving the die lifter plate 34 up and down.

That is, when a metal plate is continuously transported to an ironing die and a refrearing die, and these processes are continuously performed, for example, the ironing die and the refrearing die are not synchronized with each other. If the metal plates are pressed and separated from each other, there may be a difference in elevation between one metal plate placed continuously on each of the processing dies. In that case, if pressing is performed as it is in the conventional manner, there is a problem that wrinkles are generated in the product. In the case of equipment where the ironing die and the refrea processing die are sufficiently separated, such a problem of wrinkles is unlikely to occur, but in general-purpose equipment, the distance between them is not so large, and wrinkles are generated. Is a problem that cannot be ignored.

However, in this embodiment, the die is composed of a plurality of members as described above, and one of the members is a die lifter plate 34 having a lifter function. Therefore, the height difference of the metal plate can be corrected and wrinkles are generated. The product can be pressed without the need.

Further, in the above-mentioned conventional example, the formation of the flange portion 4 was sometimes non-uniform.
Since b enters into the inner wall of the through hole 2 of the metal plate 1 and enters the guide hole 19 of the refrea die 17 at the same time, there is no room for position correction in the metal plate 1 and this occurs. (See FIG. 6).

However, if the die 36 is used as in the present embodiment (FIG. 1), first, the metal plate 41 is fitted to the punch 33 by the die lifter plate 34, whereby the metal plate 4
The position of the through hole 42 with one collar can be corrected with respect to the punch 33, and then the punch 33 enters the guide hole 39 of the die 36 (the die lifter plate 34 also moves simultaneously with the punch 33). By pressing, a uniform flange portion 44 can be formed.

In the above description, a metal plate is formed by perforating a metal plate, and a turn-back portion of the periphery of the through-hole formed by ironing is used as a collar, and a collar is formed on the top of the collar of the collar. Although an apparatus for press-forming (refrearing) the outer flange portion has been described as a representative example, the press-forming mold according to the present invention is not limited by the illustrative description, and conforms to the above and following purposes. It is also possible to carry out the present invention with appropriate changes within the range obtained.

For example, it is of course also possible to apply a refrearing process to the color of the plate material that has not been subjected to the ironing process.

In the above-described embodiment, the surface of the step portion 37 for forming the flange of the punch 33 is a continuous U groove. However, the present invention is not limited to this. As shown in the sectional view of FIG. The punch outer member 32 may be recessed from the core member 31.

In the above embodiment, the top surface of the annular projection 35a of the die 36 is flat. However, the present invention is not limited to this. For example, the top surface may be hemispherical. . If the top surface of the annular projection 35a has a sharp shape, there is a risk of damaging the base of the collar of the plate material to be processed. Therefore, it is better to avoid this sharp shape.

[0037]

As described above, a press-formed product having no defects can be obtained by performing press working using the press-forming die according to the present invention.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a state in which a metal plate with a flange collar through-hole is manufactured using a press-molding die according to one embodiment of the present invention, and FIGS. FIG.

FIG. 2 is a cross-sectional view for explaining a curvature of a curved surface portion of an annular protrusion.

FIG. 3 is a partial cross-sectional view illustrating a step portion for forming a flange of a punch of a press mold according to another embodiment of the present invention.

FIG. 4 is a perspective view illustrating a die of a press molding die according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a conventional press-formed metal plate with a flange collar through-hole.

FIG. 6 is a cross-sectional view showing an example of a conventional method for manufacturing a metal plate with a flange collar through-hole by press working.

FIG. 7 is a perspective view of a configuration in which the die is formed of one member and an annular projection is provided on an end face of a guide hole.

[Explanation of symbols]

 1,41 Metal plate 2,42 Through hole 3,43 Collar 3a, 43a Collar base 4,44 Flange part 31 Punch core member 31a Side outer wall 32 Punch outer member 33 Punch 34 Die lifter plate 35 Die inner hollow member 35a Annular protrusion 35b Flat portion 35c Top surface 35d Outer side root portion 36 Die 37 Flange forming step 39 Guide hole

Claims (4)

[Claims] 1. A plate material to be processed having a collar erected on the periphery of a through hole is held on a support surface of a die, and a punch is driven into the hollow portion of the collar from the top side of the collar so that the punch is driven into the hollow portion of the collar. Alternatively, in the press-molding die for operating the punch to form a flange at the top of the collar, the die includes an inner hollow member having a hole into which the punch is driven, and an outer hollow member exterior to the inner hollow member. A press molding die, comprising: a member; and an annular projection on an opening end surface of the inner hollow member along an inner peripheral edge thereof. 2. The press-molding die according to claim 1, wherein the annular projection has a flared curved surface formed at a root portion on an outer peripheral side thereof. 3. The punch has a large-diameter portion and a small-diameter portion driven into the hollow portion of the collar, and a transition shoulder from the large-diameter portion to the small-diameter portion is a flange forming step. The punch has a core member and an outer member externally provided on the core member, and a joint interface between the core member and the outer member is the flange forming step. Press molding die. 4. The press-molding die according to claim 3, wherein the step for forming the flange is U-shaped.