JP2002263748A - Punching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a punching method capable of minimizing generation of 'sagging' and 'burr' which are inevitable in shearing. SOLUTION: A cut piece S is punched upward with the punching amount of not less than the thickness of a base plate by a stripper 8 and a die 14, and by a punch 11 and an ejector 16, respectively in a state in which a coil W forming the base plate and an area forming a finished are pressed and restricted. The cut piece S is punched in the reverse direction so as to be finally fitted in a die hole 14a of the die 14 while being pushed back to the original position. In this step of the reverse punching, a cut surface of the cut piece S is shaved, and the finished article with 'sagging' and 'burr' minimized can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punching method, which is a form of shearing by press working, and more particularly to a method of punching a plate-shaped base material and using the cut-out piece side as a processed product. The present invention relates to a punching method in which so-called outline punching is performed based on fine blanking (precision shearing method).

[0002]

2. Description of the Related Art A precision shearing method or a processing method called fine blanking has been known as a processing technique for suppressing the occurrence of "blurring" or "burring" inevitable in shearing. I have. this is,
Applying the phenomenon that when a high compressive stress is applied near the cut part of the base material, the plastic deformability of the material increases and cracks are less likely to occur. This is a processing method in which shearing is performed while applying compressive stress.Since the cut portion of the material receives high compressive stress and its deformability is improved, cracking does not occur and cutting must be completed only with a smooth shearing surface from beginning to end. It is said that it can be.

[0003] However, in such fine blanking, the cut surface is formed not with a fractured surface but with a shear surface as much as possible, which is effective in smoothing the cut surface. Cannot be completely prevented. The same applies to a so-called vertical punching method in which punching is performed in the opposite direction after punching out to about half the base material plate thickness.

Further, instead of the above-described fine blanking, a precision punching method for minimizing the occurrence of "burrs" and "burrs" has been proposed in Japanese Patent No. 2661287.

The precision punching method disclosed in Japanese Patent No. 2661287 is a punching method using a punching means constituted by a combination of a punch and a die. As shown in FIG. A coining process is performed on the plate material W from both front and back surfaces thereof by using a coining punch 101 having a knife-edge-shaped tip to form and form an annular groove 102, which is then hardened. Punching is performed to obtain a desired hole shape.

[0006] However, in this precision punching method, even if the occurrence of "burrs" or "burrs" can be minimized in the same manner as described above, the generation of "burrs" due to work hardening of the material is inevitable. For that reason, those “who” or “burrs” cannot be completely eliminated. Further, as described above, since two steps of coining processing as primary processing and shear punching processing as secondary processing for the purpose of imparting work hardening are indispensable, the number of steps is inevitably increased. . In addition, it is difficult to completely match the hole shape at the time of coining with the hole shape at the time of punching, and particularly when the punched section is used as a processed product (processed product), the shear surface of the section is smooth. Moreover, it does not become a straight shape, and the outer diameter of the section varies, which is not preferable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In a so-called outer shape punching process in which a plate-shaped base material is punched out and the cut-out piece side is used as a processed product, the process is performed in one step. It is an object of the present invention to provide a punching method capable of almost eliminating the occurrence of "who" or "burr" while performing the intended processing.

[0008]

According to a first aspect of the present invention, a die and an ejector inserted therein are one type, and a stripper facing the die and a punch inserted therein are provided. Is premised on a punching method in which the base material is punched out based on the shearing action between the punch and the die, and the cut-out piece is processed.

Then, the base material is pressurized and constrained by the die and the stripper, and a region of the base material to be processed is pressurized and constrained by the ejector and the punch. A process of punching a workpiece from a base material by relatively moving an ejector and a punch with respect to a die and a stripper in a state where each of the areas to be formed is pressurized and restrained, and pressing the base material and the punched workpiece respectively In the constrained state, the ejector and the punch are relatively moved with respect to the die and the stripper in the direction opposite to the direction in which the workpiece is punched, and the workpiece is pulled back in the opposite direction beyond the original position and slides with the die hole. Reversely extracting the processed product from the base material while shaving the sheared surface of the processed product based on the motion.

In this case, it is desirable that the punching amount of the processed product from the base material is equal to or greater than the thickness of the base material plate. The reason is that if the workpiece is not punched completely from the base material and is in a so-called half-punched state, when the half-punched state shifts to reverse punching, the recessed surface on the side of the workpiece will have a dent that is greater than the amount removed by shaving. Is caused, and the smoothness of the fractured surface is impaired.

Therefore, according to the first aspect of the present invention, for example, the processed product is withdrawn from the base material in a state where the base material and the region to be the processed product are individually pressurized and restrained. According to the second aspect of the present invention, the amount of over-drawing is specified to be equal to or greater than the base material plate thickness. This upper blanking process is basically the same as that of the conventional fine blanking, and therefore, the "cut" or "burr" is more or less generated on the fracture surface (shear surface) of the punched workpiece.

Subsequent to the upper punching step, the workpiece is reversely punched in the direction of returning to the original position according to the same principle as the conventional vertical punching method.
In this reverse punching step, the processed product is completely punched out of the original position in a direction opposite to the first upward pulling direction, and is punched to a position where it is pressed into the die hole.

At the time of this reverse punching, the processed product is still pressed and constrained by so-called back pressure, so that its contour is enlarged while its thickness is reduced. It slides violently with the fractured surface on the hole side of the base material in the original position, and subsequently slides vigorously also on the inner peripheral surface of the die hole while the workpiece is still pushed into the die hole. With each of these sliding operations, a shaving process is performed on the fractured surface of the processed product, so that "drow" or "burr" is gradually reduced. Then, when the reverse punching is completed, the "who" or "burr" is sharply removed, and as a result, the fracture surface of the processed product is finished smoothly, and the corner formed by the fracture surface and both front and back surfaces The edge is also sharply finished.

According to a third aspect of the present invention, on the premise of the first or second aspect, following the reverse drawing step, both molds are separated from each other and a processed product is ejected from the die by an ejector. Is characterized by including a step of protruding.

Therefore, according to the third aspect of the present invention, the processed product pushed into the die hole at the time of shaving is protruded onto the die by the ejector, and is thereby processed by an automated machine such as a handling robot or a manually processed product. Is carried out smoothly.

According to a fourth aspect of the present invention, based on the premise of the third aspect, the die and the mold are separated from each other in parallel with or after the separating operation of the two dies. It is characterized in that air blow is performed between the ejector and the ejector.

Therefore, according to the fourth aspect of the present invention, it is possible to remove chips generated by shaving from the gap between the die and the ejector or from the die. It is possible to prevent a secondary problem from occurring.

[0018]

According to the first aspect of the present invention, for example, a punching process is performed in the upper blanking and a shaving process is performed in the reverse blanking. There is almost no burrs and the cut surface shape is extremely small, and the cut surface area is extremely small, and most of the cut surface area is formed in the shear surface area, so that a sharp corner edge part and an extremely smooth cut surface shape are obtained. In addition, the secondary finishing for the purpose of removing "who" or "burrs" can be greatly simplified, and all the processes can be completed in one step.

According to the second aspect of the present invention, the initial punching amount is set to be equal to or greater than the thickness of the base material plate. As described above, no dent is formed on the cut surface, and the smoothness of the cut surface is further improved.

According to the third aspect of the present invention, following the reverse punching of the processed product, the two dies are separated from each other and the processed product is projected from the die by the ejector. In addition to the effects similar to those of the invention described in item 2, there is an effect that the processed product can be more smoothly carried out by an automated machine such as a handling robot or by manual operation.

According to the fourth aspect of the present invention, chips generated by shaving are removed by air blowing from a gap between the die and the ejector or from above the die. In addition to the effects, for example, there is an effect that it is possible to prevent the occurrence of secondary defects such as indentations caused by chips during the processing in the next cycle.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show a preferred embodiment of a method for punching an outer shape according to the present invention. It shows the situation.

As shown in FIG. 1A, the press die for punching the outer shape comprises an upper die 1 mainly composed of an upper plate 2 and a lower die 3 mainly composed of a lower plate 4. The upper plate 2 is an upper slide 5 of a press machine.
, While the lower plate 4 is also fixed to the lower slide 6 of the press machine.

The upper plate 2 supports a stripper retainer 7 which can move relative to the upper plate 2, and an annular stripper 8 is fixed to the stripper retainer 7.
A cushion pin 10 is provided between the cushion pad 9 and the stripper 8, which constitute a part of the pressure source on the upper mold 1 side.
Is provided, whereby a downward pressing force is applied to the stripper 8. A punch 11 that can move up and down is inserted in the stripper 8.
The punch 11 is urged downward by an elastic body 12 such as a compression coil spring interposed between the punch 11 and the upper plate 2.

On the other hand, a die retainer 13 which is movable relative to the lower plate 4 is supported, and an annular die 14 is fixed to the die retainer 13 so as to face the stripper 8. An elastic body 15 such as a compression coil spring is interposed between the die 14 and the lower plate 4, whereby the die 14 is urged upward. An ejector 16 that can move up and down is inserted into the die 14 so as to face the punch 11.
A cushion pin 1 is provided between the ejector 16 and a cushion pad 17 constituting a part of a pressure source on the lower mold 3 side.
8 is provided, whereby an upward pressing force is applied to the ejector 16.

When the upper and lower dies 1 and 3 approach each other as shown in FIG. 1A, the elastic force of the elastic body 12 or 15 acts on the punch 11 and the die 14, respectively. Since the cushion pressure of the cushion pad 9 or 17 acts on the ejector 16, the coil material W as the base material is restrained from above and below by pressing. That is, in this embodiment, since punching is performed in the form of a punched piece, the region of the coil material W which is to be processed is elastically pressed and restrained by the punch 11 and the ejector 16. At the same time, the peripheral region is elastically pressed and restrained by the stripper 8 and the die 14.

When the upper and lower dies 1 and 3 are still approaching from the state shown in FIG. 1A, the punch 11 on the upper die 1 side is so-called a bottom contact with the upper plate 2 as shown in FIG. When the die 14 on the lower mold 3 side is
As a result, a portion of the coil material W, which is pressurized and restrained by the punch 11 and the ejector 16, is punched upward as a piece S, and so-called fine blanking is performed. The punching amount of the section S upward at this time is at least the thickness of the coil material W or more. Further, since this fine blanking is basically the same as the conventional processing method, a droop Q1 and a burr Q2 are generated on the cut surface F of the section S as shown in FIG.

When the upper and lower dies 1 and 3 move closer from the state shown in FIG. 1B, as shown in FIG.
The coil material W is relatively pushed back (withdrawn) relative to the section S, which is pressurized and restrained by the ejector 1 and the ejector 16 and substantially acts on the back pressure, and is once punched from the coil material W. The section S is pushed into the piercing hole H which is the original position of the coil material W. At this time, the diameter of the pierced hole H of the coil material W tends to be reduced by the pressure restraining force, and at the same time, the section S is pushed into the pierced hole H while being expanded in diameter by the pressure restraining force. The cut surface of the piercing hole H on the material W side and the cut surface F on the section S side slide violently. As a result, a primary shaving process is performed, so that the sagging Q1 and the barb Q2 that have previously occurred on the cut surface F of the section S are scraped off, and as shown in FIG. Decrease.

That is, since the coil material W around the pierced hole H is constrained under pressure by the stripper 8 and the die 14, the pierced hole H itself tends to be reduced in diameter. Since the punch 11 and the ejector 16 are pressurized and constrained, the diameter tends to be conversely increased, and an appropriate shaving allowance (for example, when fine blanking is performed for the upper punching). Equivalent 0.01 ~
0.1 mm) is secured, and the burrs Q shown in FIG.
Most of 2 disappears due to sliding friction,
Similarly, the sagging Q1 shown in the figure is also significantly smaller, if not completely eliminated.

Then, as shown in FIG. 2 (A), the above withdrawal is continued until the approaching operation between the upper and lower dies 1 and 3 reaches a limit. In this state, the die 14 on the lower die 3 side is lowered. Since the stripper 8 on the upper mold 1 side is also in the bottom-butting state with respect to the plate 4 and the stripper 8 on the upper mold 1 side is also in the bottom-butting state, the section S is constrained by the punch 11 and the ejector 16 as a result. As it is, it is pushed into the die hole 14a of the die 14.

That is, the section S is pushed into the die hole 14a while the diameter of the section S is increased while the so-called back pressure is applied due to the above-mentioned pressing force. At this time, the cut surface F of the section S violently slides against the inner peripheral surface of the die hole 14a in the same manner as described above, and a secondary shaving process is performed by the friction. The shavings Q1 and the burrs Q2, which are generated earlier by the shaving, are substantially eliminated, and as shown in FIG. 3 (C), most are finished into a smooth cut surface F shape formed in the shear surface region.
At the same time, the cut surface F of the slice S is not only once subjected to the shear deformation but also the cut surface F undergoes work hardening due to the primary and secondary shaving processes. The corner edge formed by the surface F has only a slight droop Q11 due to shaving, and is finished to a sharp corner edge. On the other side, a very small burr Q12 due to shaving is also formed. Is just happening.

Thereafter, when the upper and lower dies 1 and 3 approach the limit as described above, they are separated from each other again as shown in FIG. 3B, and the section S subjected to shaving is ejected. Die 14 as a processed product P by 16
Protruded up. Then, the processed product P is carried out of the mold by automated conveyance means such as a handling robot (not shown) or manually.

Here, as shown in FIG. 2B, an air blow nozzle 20 is provided on the lower plate 4 in advance, and its directing direction is set to the die 14 and the ejector 1 on the lower mold 3 side.
6, the compressed air is blown toward the gap in parallel with or after projecting the workpiece P from the die 14. In this way, chips generated by the shaving process are collected on the die 14 or the ejector 16 and are removed by the wipe method or the vacuum suction method when the processed product P is carried out. Thereby, for example, a galling phenomenon between the die 14 and the ejector 16 can be prevented beforehand, and an indentation caused by the cutting chips does not occur in the processed product P in the next processing cycle.

FIG. 3C is a diagram showing details of the cut surface F of the processed product P finally obtained by the above-described punching process, and is shown on the opposite side of FIG. Although the slight droop Q11 and the burrs Q12 occur, the cut face F itself is almost smoothly finished with a shear surface without a rough fracture surface. The reason why the punching amount of the section S shown in FIG. 1B in the so-called upper punching step is equal to or larger than the thickness of the coil material W is, for example, the punching amount in the upper punching step such as the conventional vertical punching method. In this case, when the thickness is equal to or less than the plate thickness of the coil material W and the so-called half-blanked state is formed, a concave portion which is not erased and formed by the shaving process alone is generated on the cut surface F, and a clean portion as shown in FIG. The reason for this is that the cut surface F is not finished.

Next, an example in which the method of the present invention is applied to processing of a driven plate or a retaining plate of a multi-plate clutch (clutch pack) in an automatic transmission will be described.

First, the basic structure of the clutch will be described with reference to FIG. 4. One clutch drum 21 and a plurality of externally toothed driven plates 2 as shown in FIG.
2 and the retaining plate 23 are spline-connected. Similarly, the other clutch drum 24 and a plurality of internal toothed drive plates 2 as shown in FIG.
5 is similarly spline-connected. The driven plates 22 and the drive plates 25 are arranged alternately.

In one clutch drum 21, when hydraulic pressure is introduced between the clutch drum 21 and the clutch piston 26, the clutch piston 26 moves rightward in FIG. 23 and the drive plate 25 are pressed against each other. As a result, one clutch drum 21 and the other clutch drum 24 are integrated, and if rotational power is externally input to either one of the clutch drums 21 or 24, the power is applied between the two clutch drums 21 and 24. Communication will take place. Conversely, when the hydraulic pressure is released, the clutch piston 26 is pushed back by the return spring 27, and the driven plate 22, the retaining plate 23, and the drive plate 25 are separated from each other.
24 are independent of each other. Reference numerals 28 and 29 denote seal rings, and reference numeral 30 denotes a dish plate.

FIG. 6 is a view showing the details of the main part of FIG. 4 described above. In the crimped state of the driven plate 22 and the drive plate 25, the driven plate 22 and the drive plate 25 overlap each other in the region R, and the driven plate 22 has external teeth. Of the clutch drum 21 at the meshing portion C of.

The driven plate 22 is stamped and formed by a conventional general stamping method as described above. For example, as shown in FIG. In the peripheral portion including the tooth portion 22a (the portion that becomes the cut surface F during the punching process), the generation of the droop Q1 or the burr Q2 is inevitable. On the other hand, as described above with reference to FIG. 6, in the tooth portion 22a, power is transmitted between the tooth side surface and the mating spline tooth, so that the contact surface pressure between the two is minimized. In order to achieve this, the contact effective area must be as large as possible, that is, the length M of the straight portion at the cut surface F in FIG.
It is an important factor to secure as large as possible.

Therefore, assuming that the length M of the linear portion is as large as possible as a base material for punching and forming the driven plate 22, the burrs Q2 are eliminated as shown in FIG. In addition to the allowance Δt1,
The driven plate 22 is punched by using a base material having a thickness t3 in consideration of a machining allowance Δt2 in which a machining allowance for eliminating the Q1 is added to a machining allowance required to absorb the variation in the base material thickness itself. After processing, the front and back surfaces are polished to adjust the plate thickness t4 so that the required linear portion length M can be secured at a plate pressure t4 (t3 =
t4 + Δt1 + Δt2). Therefore, Δt1 + Δt2
Since the thickness of the part is wasted as it is, not only the material yield is poor, but also the number of processing steps is large, and a remarkable cost increase is inevitable.

On the other hand, if the driven plate 22 is machined according to the punching method of the above embodiment, as shown in FIG. 7C and FIG. Since the machining is completed by the shaving process, the minimal droop Q11 associated with the shaving process can be almost neglected. Therefore, only the allowance ΔT1 necessary for erasing the minimal burrs Q12 associated with the shaving process is considered. That's all I need to do. Therefore, as the base material plate thickness T3, the straight portion length M similar to that shown in FIG. 7A can be regarded as the finally required plate thickness of the driven plate 22, so that this finally required plate thickness T
4. T3 = T4 + Δ assuming that the above-mentioned allowance ΔT1 is added.
t ₁ is sufficient, the base material plate thickness T3 may be smaller than before (T3≪t3), and only one side of the polishing allowance ΔT1 may be polished, so that the material yield is improved and the number of processing steps is reduced. Significant reduction can be achieved.

FIG. 8 shows details of the driven plate 22 in which most of the cut surface F is formed as a shear surface, and FIG. 9A shows the driven plate 2 during punching.
2 (B) shows the relationship between the back pressure applied to No. 2 and the plate thickness change, and FIG. 2 (B) shows the relationship between the back pressure and the droop amount. FIG.
In the figure, if the base material thickness is To and the thickness of the driven plate 22 including the droop amount d after the punching is Tw, as shown in FIG.
o decreases as the back pressure P (P ₁ <P ₂ <P ₃ ) increases. Similarly, the amount d of the droop Q11 generated during the punching of the driven plate 22 is determined by the counter pressure P (P ₁
<P ₂ <P ₃ ) decreases with an increase.

As can be seen from these relations, the base material thickness To can be reduced by decreasing the droop amount d with the application of the back pressure, and as a result, the material yield is improved. Further, as described above, since nobody Q11 itself is smaller than the conventional one, there is no problem in the function of the driven plate 22 even if it is left as it is. It is necessary to remove by polishing, as described above), and the thickness T3 (see FIG. 7B) of the driven plate 22 itself can be reduced, which can contribute to downsizing of the entire clutch pack. Become like

For example, FIG. 10 is a diagram schematically showing an overlapping portion between the drive plate 25 and the driven plate 22 in the clutch shown in FIG. 6. In the conventional structure, the thickness of the driven plate 22 depends on the plate thickness t4. Quantity α
However, in the driven plate 22 of the present embodiment, since the droop amount is extremely small, it is not necessary to consider the droop amount in the thickness T4 of the driven plate. Are compared with each other, a material reduction allowance β is generated individually, and as shown in the figure, only the relationship between one drive plate 25 and two driven plates 22 is simply reduced by the dimension C by the axial center length. It can be shortened. Reference numeral 30 denotes a friction plate interposed between the drive plate 25 and the driven plate 22.

Similarly, when the driven plate 22 is viewed in a plan view, the width W of the driven plate 22 in the conventional structure has a droop amount a.
However, in the driven plate 22 of the present embodiment, since the wholly Q11 is extremely small as described above, its width dimension is sufficient to be W-2a. This can contribute to the overall size reduction.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing a processing procedure of a punching method as a preferred embodiment of the present invention.

FIG. 2 is a process explanatory view showing a processing procedure of a punching processing method following FIG. 1;

FIG. 3 is an enlarged explanatory view showing a change in a cut surface shape of a processed product.

FIG. 4 is a schematic explanatory view showing a configuration of a main part of a multi-plate clutch in an automatic transmission for a vehicle.

FIG. 5 is an explanatory plan view of a drive plate and a driven plate in FIG. 4;

FIG. 6A is an enlarged sectional view taken along line aa of FIG. 4;
(B) is a sectional view taken along the line bb in FIG.

FIG. 7 is a diagram comparing a cut surface of a driven plate by a conventional processing method and a cut surface by a processing method of the present invention.

FIG. 8 is an enlarged explanatory view of the cut surface shown in FIG.

FIG. 9 is a characteristic diagram showing the relationship between the back pressure during punching, the change ratio of the plate thickness, and the sagging amount.

FIG. 10 is a diagram comparing the conventional plate and the drive plate in the overlapped portion between the driven plate and the drive plate.

FIG. 11 is a process explanatory view showing an example of a conventional precision punching method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper mold 3 ... Lower mold 8 ... Stripper 9 ... Cushion pad (pressure source) 11 ... Punch 12 ... Elastic body 14 ... Die 15 ... Elastic body 16 ... Ejector 17 ... Cushion pad (pressure source) 20 ... Air blow nozzle 22 ... Driven plate W: coil material (base material) P: processed product S: section

Claims (4)

[Claims] 1. A method of forming a die and an ejector inserted therein into one type, and using a stripper facing the die and a punch inserted therein as the other type, thereby forming a shear between the punch and the die. A punching method in which a base material is punched out based on an action, and the cut-out section is processed into a processed product.The base material is pressed and constrained by a die and a stripper. A step of pressing the area to be formed with the ejector and the punch, and a step of moving the ejector and the punch relative to the die and the stripper with the area to be formed as the base material and the workpiece being pressed respectively. In the process of punching the workpiece from the material, and punching the ejector and punch into the die and stripper with the base material and the punched workpiece pressed and restrained respectively. Relative to the direction opposite to the time when the workpiece was removed, the workpiece was pulled back beyond the original position in the opposite direction, and the shaved surface of the workpiece was shaved based on the sliding with the die hole. And a step of reversely punching a processed product. 2. The punching method according to claim 1, wherein a punched amount of a processed product from the base material is equal to or larger than a base material plate thickness. 3. The punching process according to claim 1, further comprising a step of separating the two molds from each other and projecting a workpiece from the die by an ejector, following the reverse punching step. Method. 4. The punching process according to claim 3, wherein an air blow is performed between the die and the ejector in parallel with the separation of the two dies and after the separation operation. Method.