JP4010116B2 - Press drawing method for perforated bottomed cups - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a press-drawing method of a holed bottomed cup, and more particularly to an improvement of a press-drawing method that can effectively prevent defects such as thinning and cracking that occur during drawing.
[0002]
[Prior art]
Conventionally, there is a case where a cover is attached to an intermediate portion or the like of a shaft component. The shape of the cover used at that time is often a perforated bottomed cup in which a hole through which a shaft can be inserted is formed. Such a perforated bottomed cup is usually formed by drawing a flat plate material. This drawing process uses a die that defines the outer diameter (dimension) of the bottomed cup and a punch that defines the inner diameter (dimension) of the material in which a hole of a desired size through which the shaft can be inserted is formed. Do. At the time of drawing, molding is performed by pushing the material disposed on the upper surface of the die into the die from one side with a punch.
[0003]
When such a drawing process is performed, a tensile load concentrates on the periphery of the drawn shoulder portion, that is, the bent portion where the bottom surface and the side surface of the bottomed cup are switched due to resistance when the material is pushed into the die. As shown, the material of the part becomes thin. So-called thinning occurs. In order to recover such a thinning, for example, in Japanese Patent Laid-Open No. 8-141626, a part of the material of the bottomed cup drawn into the thinned part in the next step after the drawing is supplied. A technique to increase the thickness is shown. According to this technique, the bottom portion of the bottomed cup is coined, or the side wall portion of the bottomed cup is compressed to supply the resulting surplus material to the thinned portion.
[0004]
[Problems to be solved by the invention]
However, when a thinning occurs greatly during the drawing process and a crack occurs, there is a problem that the crack itself cannot be repaired even if a material is supplied by coining or compression processing in the next process. In addition, even when no cracks are generated, when a bottomed cup is originally formed using a thin material, there is a problem that a sufficient thickness cannot be increased because there are few surplus materials that can be supplied. Furthermore, additional work such as coining and compression is required after the drawing process, resulting in a problem that the production efficiency is lowered.
[0005]
The present invention has been made in view of the above problems, and it is possible to reliably prevent defects such as thinning and cracking caused by drawing, and press-draw molding of a perforated bottomed cup that does not cause a reduction in production efficiency. It aims to provide a method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a press drawing method for forming a bottomed cup having a hole of a predetermined shape in the center of the bottom, and a temporary opening of a size smaller than the predetermined shape in the center. the material having a hole, a drawing die which defines the outer diameter of the bottomed cup, the diaphragm punch which defines the inner diameter of the bottomed cup, placed between a position facing the said temporary opening, the throttle punch A disposing step of disposing an expanding punch that pushes the temporary opening to expand the temporary opening, and drives the expanding punch independently of the squeezing punch to expand and expand the temporary opening. A step of gradually moving the surplus material sent out by the expansion of the hole to the side of the throttle deformed portion along with the deformation of the bottomed cup; and a step of pushing the surplus material moved to the side of the throttle deformed portion with the aperture punch. , Including the temporary opening And performing thinning inhibition bottomed cup by moving the deformation portion side throttle excess material fed out by then spread.
[0007]
Here, the surplus material means a material unnecessary for a final product that is finally required.
[0008]
According to this structure, the surplus material sent out by the expansion of the temporary opening at the time of pressing the bottomed cup is sequentially moved to the drawing deformation portion side. As a result, the occurrence of thinning during pressing can be suppressed. Moreover, generation | occurrence | production of the crack itself can also be prevented by suppression of thickness reduction. Furthermore, by adjusting the size of the temporary opening, it becomes possible to adjust the amount of surplus material generated, and sufficient reduction in thickness can be suppressed.
[0009]
In order to achieve the above object, the present invention is characterized in that, in the above-described configuration, the expansion punch has a tapered shape that tapers, and gradually moves the surplus material as the bottomed cup is squeezed. And
[0010]
According to this configuration, by adjusting the taper shape of the expanding punch, it is easy to adjust the amount of movement of the surplus material to be sent out, and the surplus material can be moved smoothly.
[0011]
In order to achieve the above object, the present invention is characterized in that, in the above-described configuration, the expansion punch starts to move the surplus material slightly prior to the squeezing deformation of the bottomed cup. . According to this configuration, since the surplus material is actively moved, the occurrence of the thinning phenomenon can be reliably performed.
[0012]
The present invention provides a drawing die for defining an outer diameter of a bottomed cup having a hole having a predetermined shape at the center of the bottom, a drawing punch for specifying an inner diameter of the bottomed cup, and a first pressurizing unit for driving the drawing punch. A drawing press that forms a bottomed cup by placing a material having a temporary opening smaller than the predetermined shape at the center between the drawing die and the drawing punch. A device that is driven independently of the aperture punch at a position facing the temporary opening, and expands the temporary opening, and a second pressurizing unit that drives the expansion punch; The expansion punch is driven independently of the aperture punch so as to expand the temporary opening by the second pressurizing unit, and the aperture punch is moved by the first pressurizing unit to the temporary punch. Surplus element sent out by expanding the opening Characterized in that to be driven so as to push the. Further, the present invention is characterized in that, in the above-mentioned configuration, an ejector is disposed inside the drawing die and discharges a bottomed cup from the drawing die.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.
[0014]
FIG. 1 (a) shows a conceptual diagram of a drawing press apparatus 10 for realizing the press drawing method for a perforated bottomed cup of the present embodiment. And operation | movement of the drawing press apparatus 10 and the change state of the raw material 12 which comprises a bottomed cup are demonstrated using Fig.1 (a)-(d).
[0015]
As shown in FIG. 1A, the drawing press device 10 has a drawing die 16 supported by a die holder 14, and a first pressurizing means (not shown) such as a hydraulic pressure is provided at a position facing the drawing die 16. An aperture punch 18 that can be moved up and down by a cylinder or the like to enter the inside of the aperture die 16 is disposed. In this embodiment, an expansion punch 20, which is a characteristic component in the present embodiment, is disposed inside the aperture punch 18 so as to be movable up and down independently of the aperture punch 18. The expansion punch 20 is driven by, for example, a hydraulic cylinder 22 as second pressurizing means disposed at the upper end. An ejector 24 is disposed inside the aperture die 16. The ejector 24 is supported by a support means such as a damper (for example, a spring 24a) during the drawing process of the material 12, and according to the lowering of the drawing punch 18, that is, according to the amount of dropping of the material 12 into the drawing die 16. , Descend while supporting the material 12. On the other hand, after the drawing of the material 12 is completed and the bottomed cup is formed, the bottomed cup is raised by an elevating mechanism including a cylinder (not shown) in order to discharge the completed bottomed cup from the drawing die 16. Of course, when the spring 24a or the like is used, the bottomed cup may be discharged by the restoring force of the spring 24a. When the material 12 is drawn by the ejector 24, the material 12 is not bent more than necessary, that is, in the downward direction of the drawing punch 18, and no wrinkles are formed.
[0016]
In the present embodiment, the characteristic matter is that a temporary opening 12a having a predetermined shape, that is, a size smaller than a hole required when processing is completed, is formed in the material 12, and the temporary opening 12a is drawn by the expanding punch 20. By pushing inwardly, the surplus material constituting the temporary opening 12a, which is surplus as a finished product, is sent out and sequentially moved to prevent the thinning phenomenon that occurs during drawing.
[0017]
Hereinafter, a specific procedure for forming a bottomed cup will be described with reference to FIGS.
[0018]
As shown in FIG. 1A, a material 12 (for example, a flat material in the case of FIG. 1A) in which a temporary opening 12a is formed is disposed on the drawing die 16 (arrangement step). As is apparent from the figure, the expanding punch 20 has a tapered portion 20a that is tapered, and the tip portion thereof is formed to have a smaller diameter than the temporary opening 12a, and can be easily inserted into the temporary opening 12a. ing. When the drawing process is started, the expanding punch 20 starts to descend slightly ahead of the drawing punch 18 and gradually increases the diameter of the temporary opening 12a by the inclined surface of the tapered portion 20a. At this time, when the temporary opening 12a is expanded, the expanded portion becomes the surplus material. On the other hand, as shown in FIG. 1B, the drawing punch 18 that starts to fall slightly after the lowering of the expansion punch 20 pushes the material 12 into the inner diameter portion of the drawing die 16 (pressing process). At this time, the material 12 receives a tensile load in the edge direction due to frictional resistance caused by contact with the drawing die 16, and a force that causes a thinning phenomenon acts on the material 12. As described above, since the surplus material is pushed out by the expansion of the temporary opening 12a prior to the action of the tensile load, as schematically shown in FIG. The part A) of b), the surplus material portion is sequentially moved toward the edge of the material 12, that is, toward the deformed portion as indicated by the arrow. Since the movement of the material is gradually performed by the tapered portion 20a of the spreading punch 20, the generation of wrinkles is suppressed. As a result, even if the tensile load described above is generated, the material is moved and supplied sequentially so that no thinning occurs, so that the thinning phenomenon is substantially suppressed. Therefore, it is possible to reliably prevent the cracking phenomenon caused by the thinning phenomenon.
[0019]
FIG. 1D shows a state where the drawing process is completed and the bottomed cup 26 is completed. That is, the temporary punching hole 12a is pushed and expanded to the diameter of the desired hole 28 required when the bottomed cup 26 is completed by the expansion punch 20 and the edge end side of the material 12 is entirely inside the expansion die 16 by the expansion punch 18. It is pushed in and the side wall part of the bottomed cup 26 is also completed.
[0020]
When the bottomed cup 26 is completed, the squeezing punch 18 is raised together with the expansion punch 20. Thereafter, the ejector 24 is raised, and the bottomed cup 26 formed from the drawing die 16 is discharged. Note that, when the drawing punch 18 is pulled up, the bottomed cup 26 formed together with the drawing punch 18 may be pulled up. Therefore, if necessary, for example, the separator may protrude from the upper surface position of the drawing die 16 so that the drawing punch 18 and the bottomed cup 26 are separated.
[0021]
The configuration concept of the drawing press device 10 shown in the present embodiment is an example. At the time of the drawing press processing, the temporary opening is expanded and the surplus material fed as a result is drawn on the drawing deformation portion side at the time of drawing processing. If it is the structure which moves sequentially in the direction where thinning is easy to generate | occur | produce and it is the structure which replenishes a raw material substantially, the apparatus structure can be changed suitably and the effect similar to this embodiment can be acquired.
[0022]
In addition, the size of the provisional hole is determined in advance by molding a bottomed cup with a material that does not push and spread the provisional opening, that is, molding a bottomed cup using a material that has a hole that is required at the time of completion. It is preferable to check the degree of thinning, calculate the amount of material to be supplied, and determine the size of the provisional hole that can supply the amount. Further, according to the shape and size of the bottomed cup to be molded, the size of the hole formed in the bottom portion, etc., the inclination angle of the taper portion 20a of the expansion punch 20, the descending speed of the expansion punch 20 and the squeezing punch 18 It is desirable to adjust these appropriately.
[0023]
In addition, in this embodiment, although demonstrated using the example which uses the flat material in which the temporary opening was formed beforehand as a raw material which shape | molds a perforated bottomed cup, the material in which the temporary opening was formed If it is, the shape is arbitrary, For example, even if it uses the cup-shaped raw material which has a larger diameter than the diameter of the bottomed cup of a finished product, the effect similar to this embodiment can be acquired.
[0024]
【The invention's effect】
According to the present invention, when the bottomed cup is drawn, the temporary opening formed in the bottom is expanded and the excess material is sent out. By moving the material, a material is supplied to a portion where a tensile load acts during drawing and there is a possibility that the thinning may occur, so that it is possible to effectively suppress the occurrence of the thinning due to the tensile load. As a result, it is possible to reliably prevent cracks resulting from the thinning, and eliminate the need for a thickness adjusting process and a repairing process after the drawing process, thereby easily preventing a reduction in production efficiency.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram for explaining a configuration concept of a drawing press device that realizes a press drawing method for a holed bottomed cup according to an embodiment of the present invention, and a drawing processing procedure that involves expanding a temporary opening. is there.
FIG. 2 is an explanatory diagram for explaining a thinning phenomenon that occurs during conventional bottomed cup molding.
[Explanation of symbols]
10 Drawing Press Device, 12 Material, 12a Temporary Opening Hole, 14 Die Holder, 16 Drawing Die, 18 Drawing Punch, 20 Expansion Punch, 22 Hydraulic Cylinder, 24 Ejector, 26 Bottomed Cup, 28 Holes.

Claims (5)

A press drawing method for forming a bottomed cup having a hole of a predetermined shape in the center of the bottom,
The material having a temporary opening of the the center predetermined shape smaller size, and placement and drawing dies defining the outside diameter of the bottomed cup, between the diaphragm punch, which defines the inner diameter of the bottomed cup,
An arrangement step of driving an independent punching punch at a position facing the temporary opening, and disposing an expanding punch for expanding the temporary opening ;
The expansion punch is driven independently of the squeeze punch to expand the temporary opening, and the surplus material fed by the expansion of the temporary opening is gradually squeezed as the bottomed cup is squeezed. A process of moving to the part side;
A step of pushing the surplus material moved to the drawing deformation portion side with the drawing punch ,
Including
A press-drawing method for a perforated bottomed cup, characterized in that the thickness reduction of the bottomed cup is suppressed by moving an excess material sent out by the expansion of the temporary opening to the side of the drawing deformed portion. The method of claim 1, wherein
A method for press-drawing a perforated bottomed cup, characterized in that the expansion punch has a tapered shape and a surplus material is gradually moved as the bottomed cup is squeezed. The method according to claim 1 or claim 2, wherein
The method of press-drawing a perforated bottomed cup, characterized in that the expansion punch starts moving the surplus material slightly prior to the deformation of the bottomed cup. A drawing die that defines the outer diameter of the bottomed cup having a hole of a predetermined shape in the center of the bottom,
A squeeze punch that defines the inner diameter of the bottomed cup;
First pressurizing means for driving the aperture punch;
With
Between the drawing die and the drawing punch, a drawing press device that arranges and draws a material having a temporary opening smaller than the predetermined shape in the center, and forms the bottomed cup,
In the position facing the temporary opening, the expansion punch that is driven independently of the aperture punch and expands the temporary opening, and
Second pressurizing means for driving the expansion punch;
Have
  Driving the expansion punch independently of the aperture punch so as to expand the temporary opening by the second pressurizing means;
  A drawing press apparatus, wherein the drawing punch is driven so as to push in the surplus material sent out by the first pressurizing means by the expansion of the temporary opening. The drawing press device according to claim 4,
A squeezing press apparatus having an ejector disposed inside the squeezing die and discharging a bottomed cup from the squeezing die.

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