JPH02280926A - Punching method for preventing shear droop and burrs - Google Patents

Abstract

PURPOSE:To minimize shear droop and burr, generated on a plate stock and to improve the dimensional accuracy of a product by punching the plate stock in which work hardening is given by coining. CONSTITUTION:In a primary working, one side of the plate stock 6 is coined by a coining punch 2 to work harden the plate stock 6. In a secondary working, the plate stock 6 is punched by a punch 3 to obtain a desired shape. The quantity C coined by this coining punch varies according to the property of the plate stock, plate thickness (t), punch angle, etc. Consequently, it is possible to minimize the shear droop and burr generated in the plate stock and to improve the dimensional accuracy of the product.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to precision shear processing using a press machine, and particularly relates to a processing method for minimizing the occurrence of sagging and burrs on a product after punching. .

[Problems to be solved by conventional techniques and inventions] Conventionally,
When shearing a plate by press working, when the punch bites into the plate, it plastically deforms and causes sag and burrs on the sheared surface of the plate, which impairs the dimensional accuracy of the sheared surface, but this sag and burr is inevitable due to the mechanism. It happens.

Generally speaking, when it comes to new precision cutting methods, three main methods are considered: (a) fine blanking method, (b) new method of opposing die shearing, and (c) shaving method, all of which are effective in smoothing the punched surface properties. However, it cannot be said that the effect of suppressing droop and burrs is large.

This drooping phenomenon is caused by the punch 1 biting into the plate material 6 during the punching process, and the material in the clearance between the punch and die forming a layer that connects the double-edged beams of the punch and die, as shown in Figure 1. Due to shearing deformation, when the punch 1 descends in the direction of arrow F and bites into the plate material 6 in the initial stage of processing, droop d occurs. That is, a material shortage part e occurs in the clearance between the punch 1 and the die 4, and the plate surface sag to prevent this shortage from occurring.

This occurs on the product 7 side of the plate material 6, but not so much on the punched waste 8 side. FIG. 2 shows an example of sag occurring in a plate material having a thickness of t, and the amount of sag is quantitatively defined by the width dx of the sag and the height dy of the sag after punching. This amount varies depending on the material, but even if the clearance between the punch and die is 0, the depth dy of the hole cannot be less than 05 mm.

Regarding burrs, according to the conventional conventional punching method, as shown in FIG. A burr k like this occurs, and this burr has a width of approximately 6 to 10% of the plate thickness t. In order to prevent the occurrence of burrs, the flat pressing method and the vertical punching method are conventionally known. For example, in the flat pressing method, as shown in Figure 24, the process order is as follows: (a) is the half-blanking process, (b) is the start of the flat pressing process, (C) is the occurrence of cracks, and (d) is the completion of separation. The punching process is performed in an attempt to prevent the burr k, but these methods inevitably cause the burr d to occur in principle, as shown in FIG. 14(b).

Regarding the conventional precision punching method, to give an example of a method proposed to improve the precision of the product and reduce the loss of raw materials, Japanese Patent Laid-Open No. 56-134026 proposes cutting into the material. It is disclosed that precision shearing is performed after carving a V-shaped groove, and in Japanese Patent Application Laid-Open No. 187123/1989, an excess thickness is created on the die side of the material to be sheared, and a missing part is created on the punch side. It has been proposed that the punching surface be finished smoothly by plastically flowing the excess thickness into the missing portion, and Japanese Patent Application Laid-Open No. 174232/1983 proposes that an uneven part is provided on the planar mounting surface of the die, and the punching surface is finished smoothly. It has been proposed that the surface of the workpiece plate is plastically deformed and hardened to form holes with high accuracy, and in Japanese Patent Application Laid-open No. 195719/1982, at the peripheral edge of the tip of the punch and the same punching edge of the die, It is disclosed that a plate-shaped material is punched out using cutting edges that are respectively provided in the same direction.

Each of the above proposals has been found to be effective in improving product precision and material yield, but none of them has been found to be sufficiently effective as a means of directly preventing the occurrence of the sagging and burrs pointed out above. do not have.

In view of the above-mentioned problems, the present invention aims to implement a highly accurate punching method by minimizing the sagging and burrs that occur in the product after punching.

[Means to solve the problem]

In the present invention, two methods are proposed to solve the above problem. As claimed in claim 1, the first means is that the periphery of the tip protrudes in the shape of a knife as the primary processing, and the radial dimension thereof is slightly larger than the radial dimension of the punch. Or, a precision punching process characterized by performing coining process using a coining punch having the same dimensions, work-hardening the plate material, and then punching a workpiece of a desired shape using the punch as a secondary process. Suggest a method.

Another second means includes a female mold having a bottom surface of the same size as the contact surface of the punch and surrounded by an inclined surface at a predetermined angle from the bottom surface to the surface. A plate material is placed on a die having a die, and after coining is performed by pressing the plate material with a coining punch whose radial dimension is slightly smaller or equal to that of the punch, a second step is performed. A precision punching method is proposed, characterized in that the punch is brought into contact with the top of the convex surface of the back surface of the coining of the plate material which has been plastically deformed.

[For production]

When the processing according to the first means described in claim 1 is carried out, when coining is performed using a knife blade punch during the first processing, the inside of the material is work hardened due to plastic deformation, and this causes the second processing. During punching during processing, the amount of plastic flow of the material is reduced, resulting in less droop and burrs.

When the processing according to the second means described in claim 2 is carried out, during the first processing, the plate material is held and pressed by a coining punch and a female die to plastically deform it so that the plate material has a raised protrusion, During the secondary processing, the protruding part is brought into contact with a punch and punched (thereby, the protruding part compensates for the lack of material in the plate material,
The amount of dripping will decrease.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

3 to 9 show a first embodiment of claim 1. FIG. Third
The figure shows the amount of coining. As shown in the figure, with respect to the coining amount (coining depth) C, the amount of droop is represented by the width dxc of the droop and the depth dyc of the droop. Fig. 4 shows the shape of the coining punch 2 used for coining processing, and the peripheral part of its tip protrudes in the shape of a knife blade (hereinafter referred to as the knife blade), and this knife blade forms a punch angle θ with respect to the axis. This punch angle is within the range of 90°>θ>0, and this varies depending on the material of the rough material, the plate thickness, etc., but the smaller the punch angle θ, the smaller the amount of sag during coining. W represents the width of the straight portion of the tip of the knife blade 2a, and is preferably in the range of 1 mm≧Ws≧0.

FIG. 5 shows the shape of the punch 3, and the width of the punch 30, that is, the punching dimension W, and the width of the coining punch 2, that is, the coining dimension We, Wc=W, +α, where 2 mm≧α≧ There is a relationship of 0. That is, the coining punch 20 width W0
is a slight difference α(0,2
The dimensions are greater than or equal to (α=0) by 111 [0≧α≧0).

Next, the processing method of the present invention is shown in FIG. Reference numeral 2 indicates the coining punch described above, 3 indicates a punching punch, and a plate material 6 is placed on the die 4. First, as the primary processing, the 6th
As shown in the left half of the figure, a coining process is performed on one side of the plate material 6 using the coining punch 2, and thereby the plate material 6
After work-hardening, as a secondary process, a punching process is performed using a punch 3 as shown in the left half of FIG. 6 to form a desired shape. The coining amount C by this coining punch varies depending on the material of the plate, the plate pressure t, the punch angle θ, etc., but it is generally desirable to be 25% or less of the plate thickness t.

FIG. 7 shows the relationship between the coining amount C and the droop when knife blade coining is performed as shown in FIG. 3 using the coining punch shown in FIG. 4. In the figure,
DXO is the width and DYO is the depth of the groove created by the conventional punching method.
The width and height of the droop after coining on the same plate are shown as dxc and dyc. At that time, the punch angle θ of the knife blade is θ1 < θ2 < θ3. As shown in the figure, both the droop width dXc, the droop depth, and dyo are smaller as θ is smaller, but the difference in droop depth dYc due to θ is It's not that noticeable.

Next, FIG. 8 shows the relationship between the amount of coining and the amount of sag after punching with the punch 3 after knife blade coining with the coining punch 2 described above. In the figure, the resulting droop width is indicated by dx, and the resulting droop depth is indicated by dy (see FIG. 2). The punch 3 at this time is Wc=W as described above.

It is desirable that the relationship is +α, 2 mm≧α≧00.

According to the results shown in FIGS. 7 and 8, in this case, the case of coining ic+ and knife blade punching angle θ1 ultimately results in the minimum amount of droop, and can be determined to be optimal.

However, this optimum value changes depending on conditions such as the material of the plate used, the plate thickness, and the temporary pressing force.

As a result of comparing the method of punching with a punch after coining using the knife blade coining punch described above and the method of punching out a plate with a conventionally commonly used punch, the droop depth was approximately 173, and the droop width was approximately 173. about 1
It was found that the amount of sagging can be reduced in each case. This is because the area around the coining is work hardened by knife blade coining, which reduces the amount of plastic flow caused by the punch digging into the material at the beginning of the punching process. FIG. 9 shows a pattern in which the hardness distribution within the material changed as a result of coining with the knife blade punch. The figure shows an example of the results of measuring Vickers hardness (Hv) according to the depth (mm) inside the material. This shows that the value is higher than Katasa Ha.

Next, a second embodiment of claim 1 is shown in FIGS. 10 to 13. In this embodiment, using the same knife and coining punch 2 as those used in the first embodiment,
After coining is performed on both sides of the plate material 60 simultaneously or one side at a time from the top and bottom directions of the plate material 6, it is punched out with a punch 3. The coining amount C by the coining punch 2 at this time is determined by the material of the plate 6, the plate thickness t1, the punch angle θ(
(see FIGS. 4 to 6), but it is generally desirable that the thickness be 25% or less of the plate thickness. The angle θ of the con-yung bunch 2 is in the range of 45°≧θ≧0, and varies depending on the material and thickness of the plate 6, etc., but the smaller θ is, the smaller the sag during coining becomes. Further, the width W of the straight portion at the tip of the coining punch 2 is preferably in the range of 0.1 mm≧W, ≧0. The relationship between the punching dimension Wp and the coining dimension Wc is Wc=WP+α. Here, 0kuαkuM and M
is a value as small as possible (0,
01~0,1)".

As shown in FIG. 10, using the coining punch 2 that is generally similar to that of the first embodiment, the coining punch 2 simultaneously pinches the plate material 6 held by the temporary presser 5 from above and below (see FIG. 10). a)) Coining is performed by simultaneously pressing both sides of the plate material 60 from the upper and lower sides (Fig. 10 (b)
)) This is formed into a shape as shown in FIG. 10(C). The plate material 6 thus formed is punched out with a punch 3 as shown in FIG. 10(d) to form a finished product 7. Further, as shown in Fig. 11, the plate material is restrained with a temporary presser 5 and the coining punch 2 is applied (Fig. 11 (a)), and coining is performed on only one side first (Fig. 11 (b)). ,
In the next step, the other side is coined (Fig. 11(C)). As a result, the coined portion of the coined plate material (FIG. 11(d)) is punched out using the punch 3 (FIG. 11(e)).

According to the second embodiment described above, by coining both the upper and lower surfaces of the plate material 6 at the same time or one side at a time, and then punching,
It is possible to prevent the occurrence of sag on the upper and lower surfaces of the plate material, and also to prevent burrs.

Although it varies depending on the precision of the die of the punching surface, it is approximately 20J.
! With the exception of the formation of a step of about m, this process makes it possible to form a hole with a sharp edge similar to that before cutting or polishing using press processing.

Moreover, according to this, as shown in FIG. 12, the restriction on the width dimension (width dimension of punching) a with respect to the plate thickness t is small. Although it depends on the material of the plate material, according to the conventional method, it is possible to achieve a=Q of about 7 and a=Q of about 4.

In addition, with conventional methods, it is difficult to limit half-cutting of materials that are prone to cracking, such as spring steel and high carbon steel, and not only does the shear penetrate through and prevent burrs, but there is also the risk of coming off during progressive feeding and resulting in double punching. ·be.

According to this proposed method, it is possible to reliably prevent sagging and burrs, and there is no need to worry about them coming off during sequential feeding.

Further, even a shape as shown in FIG. 13, for example, which cannot be processed by cutting or grinding due to poor productivity, can be easily processed by the proposed method.

FIG. 14 shows a comparison of punched cross sections obtained by various punching methods. (a) shows a case of conventional punching, in which droop d and burr k occur at the upper and lower parts of the cross section, respectively. (
b) is a case where the conventional upper and lower punching method or flat pressing method is used, and there is no burr k, but droops d occur at the top and bottom of the cross section. (C
) is based on the single-sided coining method of the first embodiment, and there is no droop d at the top of the cross section because d=Q, but there is a burr k at the bottom. (d) is obtained by the double-sided coining method of the second embodiment, and there is no droop d or burr k on the top and bottom of the cross section.

Next, an embodiment related to claim 2 of the present invention will be described as a third embodiment. The basic idea of the present invention is to raise the plate material in advance by an amount corresponding to the sag d that would be reduced by the sagging caused by the sag shown in FIG. 1.

That is, as shown in FIG. 15, the plate material is punched in the f direction with a coining punch so that the volume of the built-up portion V2 is sufficiently raised to compensate for the amount of sag dx and dy of the portion d in FIG. 1. After bending and plastically deforming it, it is punched out with a punch 3 in the direction of F, which is opposite to f. This results in
The volume of Vl corresponding to the material shortage part e in Figure 1 is compensated by the volume of V2 raised by coining (hereinafter referred to as overlay coining), which has the same effect as overlaying, and the finished surface looks like d. A punched plate with a smooth surface is obtained without avalanche formation. For this purpose, fill-up volume (
The relationship Va)>material shortage volume (Vl) that occurs during punching is a necessary condition; otherwise, sagging will occur.

Next, an example using the above method is shown in FIGS. 16 to 19 in order of processing steps. FIG. 16 shows a state in which the overlay coining punch 20 is set on the overlay recoiling die 40 before entering the overlay coining process. FIG. 17 shows a state in which the overlay coining punch 20 descends in the f direction to press the plate material and plastically deform it. In the figure, WPl... overlay coining punch width, θP1...
Overlay coining punch angle, Ws... Straight part of the overlay coining punch tip, Wh... Overlay coining amount, W,... Overlay coining die width, Ch... Overlay coining height, θ, ... Overlay reclining die angle, t ... Indicates plate thickness, (a) 0° ≦θpl<90° (c) Wp+≦W.

(d) ch/l≦, 5 Determine each dimension so that

After the overlay coining process is completed in the above state, the plate material is taken out, turned upside down, and the punching process begins as shown in FIG. 18. Top surface 6 of plate material 6 that has been plastically deformed and raised
A is pressed with the punch 3 to perform punching in the F direction, and as shown in FIG. 19, when the punching chips 8 are punched out, the raised build-up portion V2 undergoes plastic flow and fills the material shortage V+, After punching, the punch returns to a flat surface and no sagging occurs. After this, even if some undulations remain on the product, a product with a smooth finished surface can be easily obtained by hitting it with a flat plate. The dimensions in this drawing process are preferably under the following conditions.

In the figure, W, 2... Punch width, Ws... Punch tip straight part, θ, 2...
・Damp punch angle! ...Mold clearance: (a) Wa = Wp2 (b), 1 mm≧Ws≧0 (c) 0°≦θP2≦90° Also, although it varies depending on the material of the rough material, plate thickness, etc., in general θp
The smaller the angle of HθP2, the more it is possible to suppress sag after punching. As mentioned above, V2 > V.

Measuring Coining Punch 20 and Measuring Die 4 to satisfy
By determining the dimensions of 0 and the punch 3, it becomes possible to perform punching with zero sag.

In addition, in the above method, after coining, the workpiece plate material was turned upside down and punched, but this work was performed by setting the die upward without turning it over, and by directing the punching direction upward. It is also possible to do so, and the direction of punching is not particularly limited and can be set as appropriate depending on the situation of the equipment.

Next, an example in which a product was manufactured by the punching method based on claim 1 or claim 2 of the present invention will be described as a fourth example.

The product manufactured by the punching method according to the present invention has a second
The plate used for the viscous coupling shown in Fig. 0 and the inner plate shown in Figs. 21 (a) and (b) ) 15 (
c) Each of the outer plates 13 shown in (d) is processed to form slits or holes.

First, a general explanation of the viscous coupling will be given.As shown in FIG.
As shown in the figure, an outer plate 13 and an inner plate 15 are placed in a sealed chamber 10 filled with highly viscous silicone oil.
When a rotation difference occurs between the input and output members 11 and 12 (for example, the left and right wheels of a car) that are arranged alternately and are rotatable relative to each other (for example, when one wheel of the car falls into a groove and slips), the input end 11 It transmits the necessary torque (for wheel escape) to the output side 12. However, if the transmitted torque is not sufficient, a rotation difference between the outer plate 13 and the inner plate 15 will continue to occur, and during this time, the temperature and pressure of the silicone oil in the viscous coupling will increase, and eventually the outer plate 13 and the inner plate 15 will increase in temperature and pressure. are in metallic contact, and the input/output members 11 and 12 (between the left and right wheels) are directly connected, and a large torque is transmitted. (As a result, the wheels can escape from the groove,
) This state where both plates are directly connected is called a hump state. Then, when a direct connection is established and the difference in rotation between the two plates disappears, the temperature and pressure of the silicone oil decrease, returning to a steady state.

If the hang does not occur, the temperature and pressure of the silicone oil will rise, maintaining a high temperature and high pressure state, and if the operation continues, the viscous coupling will be destroyed. Therefore, the hump phenomenon is less likely to occur, and if the number of humps is small, the life of the viscous coupling will be shortened.

Next, in manufacturing the conventional plate of the above-mentioned viscous coupling, holes 13a1 and slits 13b1 are provided in the outer plate 13 as shown in FIG. 21(d), or as shown in FIG. 21(b). The elongated hole 15C provided in the inner plate 15 is very difficult to machine by cutting or grinding, and for this reason, it has conventionally been manufactured by press punching. Therefore, according to the conventional method, sag occurs on the cross section of the slit, etc., and this sag has a large influence on the number of times the viscous coupling is hung, which is used to determine the life of the viscous coupling. , sag depth dy) is large, leakage of silicone oil between the plates becomes large, the hang phenomenon becomes less likely to occur, and the number of hangs decreases.

Based on the above, FIG. 22 shows a processing method performed to reduce the amount of sag in the hole 13a and the sleeve 13b of the outer plate. FIG. 22(a) shows a situation where coining is being performed using a coining punch 2 equipped with a knife blade.
(b) shows a state in which punching is performed using the punch 3 after coining.

As a result, with respect to the plate thickness t, the sag could be suppressed to a small value such that the sag width was dx≦, the 2t1 sag height was dy≦, and 05t, and a small sag amount equivalent to cutting or grinding could be obtained.

Further, FIG. 23 shows a comparison of the amount of sagging between a punched product made by the conventional method and a punched product made by the method of the present invention. Drop width d
It is shown that the product of the present invention has a smaller amount of sag in both x and sag depth dy.

Table 1 shows a comparison table of the effects of using a plate produced by this process and a conventional plate in a viscous coupling.

Table 1: The evaluation conditions for viscous couplings shown here are that both the conventional product and the product of the present invention were operated under exactly the same conditions, and the number of humps that occurred within the same period was compared. This is proportional to the life of the viscous coupling. As shown in the table, according to this processing method, the number of hangs is 5 to 6 times higher than that of conventional products, and the life span is correspondingly extended, which shows that the effect of the present invention is great.

〔Effect of the invention〕

According to the present invention, by punching a plate material that has been work-hardened or plastically deformed through coining processing, it is possible to minimize droop and burrs that occur in the plate material and improve the dimensional accuracy of the product. .

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the principle of sagging during shearing.
Fig. 2 is an explanatory diagram of the definition of the amount of sag, Fig. 3 is an explanatory diagram showing the amount of sag during coining, Fig. 4 is a sectional view of the knife blade coining punch, Fig. 5 is a sectional view of the punch, and Fig. 6 is a sectional view of the punch.
An explanatory diagram of a processing method using a combination of knife blade punch coining and punching punch according to the first embodiment, FIG. 7 is a droop amount-coining amount diagram during knife blade punch coining, and FIG. 8 is a diagram of the amount of coining in FIG. The amount of sagging during punching after coining with a knife blade - coining amount diagram, Figure 9 is a hardness distribution diagram of the material after coining with a knife blade, Figures 10 to 13 show the second embodiment, Figure 10 shows (a) to (d) the coining and punching operations performed simultaneously from the top and bottom directions.
), Fig. 11 shows the punching work after coining one side from the top and bottom in order of process (a) to (e), Fig. 12 shows the width dimension and plate thickness, Fig. 13 shows an example of a difficult shape that is easy to process according to this proposal, and the first
Figure 4 shows a comparison of punched cross sections obtained by various punching methods. FIG. 15 is a principle diagram of a processing method for suppressing the amount of droop using plastic deformation according to the third embodiment, FIGS. 16 to 19 show the processing steps of the third embodiment, and FIG. Fig. 17 is an explanatory diagram of the implementation state of coining processing in the first processing, Fig. 18 is a set diagram before the first processing with a punch in the secondary processing, 1st
Figure 9 is an explanatory diagram of the execution state of the punching process of the secondary process,
Figure 0 is a cross-sectional view of the viscous scalpel prelug, and Figure 21 shows each plate of the viscous coupling.
b) shows the inner plate, and (C) and (d) show the outer plate. FIG. 22 shows a plate of a viscous coupling being processed by the method of Example 1 of the present invention, (a
) is a cross-sectional view showing the state during knife blade punch coining processing, (b) is a cross-sectional view showing the state during punching processing, and Fig. 23 shows the products when punching a plate of a viscous coupling using the conventional method and the method of the present invention. A comparison diagram of the amount of droop, FIG. 24, shows the effect of the conventional flat pressing method in the order of steps (a) to (d). 1... Punch, 2... Coining punch, 3... Punch punch, 4... Dice, 6...
Board material.

Claims (1)

[Scope of Claims] 1. A method for punching a plate using a punching means constituted by a combination of a punch and a die, in which the periphery of the tip protrudes into a knife blade shape as the primary processing. After coining is performed using a coining punch whose radial dimension is slightly larger or equal to the radial dimension of the punch, and the plate material is work-hardened, it is shaped into the desired shape using the punch as a secondary process. A precision punching method characterized by punching a processed product. 2. A method for punching a plate material using a punching means constituted by a combination of a punch and a die, which has a bottom surface of the same size as the contact surface of the punch as the primary processing, and the surface is cut from the bottom surface. A plate material is placed on a die having a female die formed by being surrounded by slopes at a predetermined angle, and a coining punch having a radial dimension slightly smaller than or equal to the punch punch After pressing the plate material and performing coining, the second
A precision punching method characterized in that, as a subsequent processing, punching is performed by bringing the punch into contact with the top of a convex portion on the back surface of the contact surface of the coining of the plastically deformed plate material.