JP2003181560A - Press working method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press working method capable of preventing at least some shoulder saggings in punching out a work piece from a plate material to easily form an accurate contour. <P>SOLUTION: In the method, the work piece is cut off at a required distance by a certain width nearly in parallel with a partial contour (e.g. an outline) of the product on a pre-worked plate material (work W) at a distance to form at least one slit (11, etc.), in a first press work process (range A). In a second press work process, it makes shaving along the partial contour of the work piece while pushing off pads (31, etc.), into the slit (range B), and then cuts off along the circumference of the entire work piece contour to blank out the work piece from the work W and form, for instance, a flange 40 in a third press work process. Thus such an outline without any shoulder sagging is formed on a shaving line t portion to ensure a fastened seat of the flange 40. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press working method, and more particularly to a press working method for punching a plate-shaped material into a product having a predetermined shape, for example, a flange used for an exhaust system of an automobile.

[0002]

2. Description of the Related Art Usually, when a product having a predetermined shape is manufactured from a plate-shaped material by press working, particularly press punching, sagging occurs at the shoulders (corners) at the time of punching, so-called "shoulder sagging". Becomes Since the shoulder sag naturally hinders the flatness of the product, it is desirable to make it as small as possible. In particular, for a pipe connection joint flange (hereinafter, simply referred to as a flange) in an automobile exhaust system, it is necessary to secure a fastening seat surface (flat surface) of a screwing means such as a bolt or a nut as a connecting means with a connection counterpart component. Therefore, if there is shoulder sag, that portion cannot be used as a fastening seat surface. On the other hand, it is required to make the flange as small as possible in order to reduce the mounting space on the vehicle and reduce the weight, and it is necessary to minimize the outer shape of the flange. Therefore, the outer shape of the flange (contour of the shoulder) is enlarged. It cannot be helped, and it is difficult to secure a sufficient fastening seat surface.

As a conventional technique related to the sagging of the shoulder portion that occurs during punching, for example, Japanese Patent Laid-Open No. 2000-210732 discloses a precision punching method known as fine blanking from the viewpoint of occurrence of burrs during press punching. A burr-free working method has been proposed, which aims to prevent the excess thickness due to fine blanking from adversely affecting the flatness of the product and to perform burr-free punching. According to the method described in the publication, a slit hole is punched out at a position slightly larger than the outer circumference of the product, extrusion processing is first performed, and then reversal punching is performed to form a sag surface on both front and back sides, and thus, a burr is formed. By preventing the generation of the excess and introducing the excess thickness to the slit hole, the excess thickness does not adversely affect the flatness of the product (paragraphs [0001] to [0005], [00] of the publication).
15] etc.).

Further, Japanese Patent Laid-Open No. 2000-288652 discloses a highly accurate hole having a smooth cutting surface over the entire cut surface without causing defects such as cracks in a Mg alloy plate manufactured by thixomolding. For the purpose of providing a method of efficiently obtaining a press with one stroke, the clearance with the die is set to the maximum punching clearance that does not cause a defective cut surface, and the punching is performed, followed by shaving in the same stroke. A precision punching method has been proposed, which is intended to carry out shaving.

[0005]

When the above-mentioned flange is formed by the conventional press punching process, it is necessary to further perform a cutting process in a later step in order to secure a fastening seat surface. Since this causes a cost increase, it is desired that both the fastening seating surface and the outer shape (contour of the shoulder portion) be minimized by only pressing.

As a means for minimizing the shoulder sag, for example, if the burr-free processing method described in Japanese Patent Laid-Open No. 2000-210732 is adopted, this method is
Originally, it is said that the formation of burrs is prevented on both the front and back sides to prevent burrs from occurring, and the main purpose is to prevent burrs from occurring. There is no clear suggestion in terms of preventing In addition, although this method distributes the burrs at the corners on each of the two surfaces and reduces the occurrence of burrs per one surface, the burrs still remain. Moreover, since the fine blanking device and the dedicated mold are expensive and have complicated processes, it is difficult to reduce the manufacturing cost and the cycle time.

On the other hand, the above-mentioned Japanese Patent Laid-Open No. 2000-288.
The method described in Japanese Patent No. 652 uses shaving rather than fine blanking, but the range (amount of surplus) that can be scraped off by a shaving blade is limited, and it is similar to the flange described above. The shoulder sag once formed cannot be completely removed. This is due to the shape of the conventional shaving blade (having a blade portion perpendicular to the traveling direction), and also because the removed surplus becomes an obstacle during shaving. In order to smoothly perform shaving, it is necessary to appropriately remove the surplus during shaving as scrap.

In particular, in the above-mentioned flange, at least the fastening is required in order to achieve both the trade-offs of securing the fastening seat surface and minimizing the outer shape (shoulder contour) without requiring cutting work as a post process. It is desirable to minimize shoulder sag where necessary to secure the seating surface.

Therefore, it is an object of the present invention to provide a press working method capable of preventing at least part of shoulder sag when punching a product from a plate-like material and easily forming an accurate contour.

[0010]

In order to solve the above-mentioned problems, the present invention provides a press working method for punching a product having a predetermined shape from a plate-shaped material as described in claim 1, wherein the plate-shaped material before processing is used. A first pressing step of cutting at least one slit in a predetermined width substantially parallel to a part of the contour of the product on the material to form at least one slit, and pushing the excess thickness into the slit. It is characterized by including a second pressing step of shaving along a part of the contour of the product and a third pressing step of cutting along the entire circumference of the contour of the product. Although there are various modes of the shaving method, the shaving of the present invention is carried out as a part of the pressing step, and is therefore the second pressing step.

In particular, as described in claim 2, the contour of the product is the outer shape of the product, and in the first pressing step, a predetermined distance is provided outside a part of the outer shape of the product. At least one slit is formed by cutting a predetermined width in parallel with each other, and in the second pressing step, shaving is performed along a part of the outer shape of the product while pushing the excess thickness into the slit. In the third pressing step, the product may be cut along the entire circumference of the outer shape to punch the product from the plate-shaped material.

In the press working method according to claim 1 or 2, as described in claim 3, in the first pressing step, a part of the contour of the product is shaving by a trim blade, A predetermined distance between a part of the contour of the product and the slit is set so that the cutting load of the plate-shaped material at the time of shaving by the trim blade in the first pressing step is equal to that at the time of cutting in the third pressing step. The distance may be set to satisfy the condition that the load is smaller than the deformation load of the plate-shaped material.

Further, in the pressing method according to claim 1, 2 or 3, as described in claim 4, in the second pressing step, the extra thickness is left in the slit, In the third pressing step, the plate-shaped material may be separated.

Further, in the press working method according to claim 1, 2, 3 or 4, as described in claim 5,
The first pressing step, the second pressing step and the third pressing step may be simultaneously performed by a progressive die.

Further, in the press working method according to claim 3, 4 or 5, as described in claim 6, the trim blade is used for the plate-shaped material including a part of the outer shape of the product. It is advisable to have a cutting edge angle formed by a right-angled surface and a surface extending from the surface to the outside of the slit, and to set the cutting edge angle to an acute angle. For example, this cutting edge angle may be set to 45 °.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the press working method of the present invention will be described below with reference to the drawings. Figure 1
1 shows a work W in the process of being produced when a flange 40 to be used for an exhaust system of an automobile is manufactured from a work W of a metal plate-shaped material by the press working method of the present invention.
(A) part showing the state after the pressing step, (B) part showing the state after the second pressing step, and (C) part showing the state after the third pressing step. Also, FIG.
Shows that these three steps are of progressive type (upper mold UD is shown in FIG. 2).
2 shows a state in which the plate-shaped work W extends in the left-right direction, and moves to the right at each end of the press stroke after the press device (not shown) is activated, The work W is processed in the sequential feeding step in the order of (1), (2) and (3). Therefore, FIG.
From (3) onward, the above three steps are simultaneously performed. The state at the time of trim shaving in the second pressing step is shown in the upper part of FIG. 3, and the flange 40 which is the product of the present embodiment is shown in FIG.

The first pressing step in this embodiment is
Part of the contour of the product on the workpiece W of the plate-shaped material before processing (in this embodiment, the small hole 2 for bolt insertion in the outer periphery h).
The slits 11, 12, and 13 are formed by cutting a predetermined width (sw) substantially in parallel with each other at a predetermined distance with respect to (1, 22, 23, and the like), which is referred to as a trim punching step in this embodiment. The second pressing step is to shave along a part of the contour of the product while pushing the excess thickness into the slits 11, 12, and 13. In this embodiment, the trim blade TC shown in the upper stage of FIG. 3 is used. The shaving process is performed as part of the pressing process, and is called the trim shaving process. Then, the third pressing step cuts along the entire circumference of the contour (outer circumference h) of the product, and is referred to as an outer shape cutting step in the present embodiment.

Then, referring to FIGS. 1 and 2, first,
The trim punching process (the (A) portion of FIGS. 1 and 2) which is the first pressing process will be described. First, the upper die UD is driven downward with respect to the work W, and three slits (long holes)
11, 12, 13 and the three small holes 21, 22, 23 are punched simultaneously. The small holes 21, 22, 23 may be punched separately. At this time, the slits 11, 1
2 and 13 are outside of a part of the contour of the product after machining (outer periphery h of the flange 40 in this embodiment) (the vicinity of the small holes 21, 22, 23 in this embodiment) with respect to the workpiece W before machining. And a predetermined distance (margin width rw in this embodiment).
Perforated separately.

The predetermined distance (surplus width rw) is such that the cutting load of the work W during shaving by the trim blade TC in the next trim shaving step is smaller than the deformation load of the work W during cutting in the subsequent contour removing step. Is set to a distance that satisfies the condition that Therefore, the margin width rw may be set to any value within the range of “deformation load of work W> cutting load of work W” in the trim shaving process, but if it is set to a too large value, the margin around the product Since the amount of scrap will increase, the yield will deteriorate.

Similarly, the width s of the slits 11, 12, 13
w is also set to an appropriate value in relation to the trim blade TC in the next step described later. Also, the slits 11, 12, 1
The perforation position and the length of No. 3 are set according to the position (range) on the outer circumference where the shoulder sag should be minimized with respect to the product. For example, in the flange 40 that is the product of the present embodiment, a bolt (not shown) that constitutes a screwing means (bolt / nut).
For the small holes 21, 22, and 23 that penetrate through, a fastening seat surface (inside the circle indicated by the two-dot chain line in FIG. 4) is required around them, so there is shoulder sag at least in the vicinity of the outer circumference h. Instead, the drilling positions and lengths of the slits 11, 12, and 13 are determined so that the outer periphery of the fastening seat surface matches the outer shape of the product.

Next, the trim shaving step of the second pressing step (portion (B) of FIGS. 1 and 2) will be described. In the present embodiment, the portion where the shoulder sag should not exist on the outer periphery h of the flange 40 as the product is between the points a and f, between the points b and c, and between the points d and e in FIG. Between these points, the trim blade TC supported by the upper die UD is driven downward to these parts for trim shaving as shown in the upper part of FIG. That is, as the upper die UD descends, the trim blade TC shears off the metal material on the side portion of the work W and scrapes off the side portion. In the present embodiment, as shown in the upper stage of FIG. The surplus thickness 31 is pushed to the outside of the slit 11 (on the right side in FIG. 3), leaving the lower end of the slit 11.

In this case, the trim blade TC is formed in a wedge shape, and has a surface perpendicular to the work W including a part of the outer shape of the product and slits 11, 12, 13 from this surface.
It is desirable to set the cutting edge angle formed by the surface facing toward the outer side to an acute angle, and in this embodiment, it is set to 45 °. Most of the projected area of the trim blade TC onto the work W is set so as to overlap the slits 11, 12, and 13, but the outermost end thereof should not be located outside the slits 11, 12, and 13. It is desirable to set to. In addition, the outermost ends of the extra thicknesses 31, 32, 33 that are pushed outward as the trim blade TC descends are slits 11, 12 ,.
It is desirable to set so as not to interfere with 13.

The trim blade TC may be lowered below the lower surface of the work W to completely separate the extra thicknesses 31, 32, 33 from the work W. However, for the reasons that the separated surpluses 31, 32, 33 need to be recovered as scraps at this stage, and that only the upper surface of the work W for which shoulder sagging is to be trimmed, it is necessary to trim shave. Trim blade TC as above
It is efficient to stop the lowering of the workpieces halfway and keep the surplus thicknesses 31, 32, 33 from being separated from the work W. Therefore, in the present embodiment, the trim shaving is performed by 7 mm for the plate thickness of 10 mm, and the surplus thickness 31, 3 is left for the remaining 3 mm.
2 and 33 are set to be connected to the work W.

By the above trim shaving process, the shaving line t having no shoulder sag between the points a and f of the work W, the points b and c, and the points d and e. Is formed. In this case, the slits 11, 12, and 13 are formed in the previous step, and the "deformation load of the work W>
There is a relation of "cutting load of work W", and surplus 3
Since 1, 32, 33 are easily pushed into the slits 11, 12, 13, the shoulder sag on the upper surface can be minimized. Then, the extra thicknesses 31, 32, 33 are held in the slits 11, 12, 13 as shown in FIG. When the trim blades TC are used to separate the surplus thicknesses 31, 32, 33, the surplus thicknesses 31, 32, 33 are the trim blades T.
By C, the outside thereof, that is, the slits 11, 12, 13
After being pushed inside, it is separated, dropped from there, and collected as scrap. Therefore, in any case, it is possible to prevent the surplus thicknesses 31, 32, 33 from interfering with the trim shaving or the shearing in the external shape removal in the subsequent process.

When the trim shaving process of the present embodiment shown in the upper stage of FIG. 3 is compared with the conventional method of shaving after press working shown in the lower stage of FIG. 3, for example, the shoulder sag range in the conventional method is compared. While dw was 6 mm or more, in the present embodiment, it was suppressed to within 1 mm, and it was possible to achieve a level that practically does not cause any problem in the product. Regarding the conventional method, the two-dot chain line i in the lower part of FIG. 3 indicates the end face of the hole formed by shearing in the ordinary press working, and the solid line j indicates the shaving surface. As described above, according to the present embodiment, the slits 11, 1 are formed in the previous step.
2 and 13 are formed, and the surplus thicknesses 31, 32, and 33 are easily formed by slits 11, 12, and as the trim blade TC descends.
Since it is pushed into 13, the trim shaving can be performed reliably and with high precision, and the shoulder sag can be minimized.

Next, the outer shape removing step (portion (C) in FIGS. 1 and 2) performed as the third pressing step will be described. Here, the upper die UD is driven downward with respect to the work W to punch out the large-diameter communication hole 41 shown by the two-dot chain line in FIG. 1, and the entire circumference of the contour of the product, that is, the outer circumference h (FIG. 4).
Is sheared along a portion corresponding to the outer shape 42 of the flange 40 shown in FIG. Therefore, the fastening seat surface around the small holes 21, 22, and 23 (within the range indicated by the chain double-dashed line in FIG. 4) is cut while a part of the outer periphery thereof overlaps with the outer shape 42 of the flange 40 as the product. It will be. As a result, as shown in FIG. 4, the normal shoulder sag is maintained between the points a and b, the points c and d, and the points e and f of the flange 40. However, the state of the shoulder formed by the trim shaving process is maintained between points a and f, between points b and c, and between points d and e, and shoulder sagging occurs. It does not occur, and the desired fastening seat surface can be secured. still,
FIG. 4 shows the shoulder sag on the upper surface in an exaggerated manner for ease of understanding.

In this embodiment, the shoulder sagging prevention portion is limited to a part of the upper surface of the product, but the length of the portion regardless of the upper surface or the lower surface is trimmed as a part of the pressing process. It can be arbitrarily set as long as shaving is possible. Further, in the present embodiment, the description has been made by unifying to the downward driving of the upper mold UD, but the punching direction (pressing direction) by the pressing device may be reversed. Further, it is also possible to use fine blanking equipment instead of an ordinary press device, or to carry out in combination with fine blanking. Furthermore, the product is not limited to the flange 40 described above, but can be applied to various products.

[0028]

Since the present invention is constructed as described above, it has the following effects. That is, in the press working method according to claim 1, when the product is punched out from the plate-shaped material, the shoulder sag is applied over an arbitrary range of the product by only slightly modifying the conventional press device and working method. Since it can be minimized, accurate contours can be easily formed, and expensive and complicated fine blanking is not used, and no additional cutting process is required. Can be formed inexpensively and quickly.

In particular, by constructing as described in claim 2, it is possible to inexpensively and quickly form a product having no shoulder sag in a predetermined portion of the outer shape of the product.
When manufacturing a flange to be used for the exhaust system of an automobile, the amount of shoulder sag that interferes with the fastening seat surface is suppressed to a level that is practically no problem,
Since the desired seating surface can be secured, the degree of freedom in design is dramatically increased.

Further, with the structure as set forth in claim 3, the trim blade further facilitates the shaving, so that the shape accuracy of the shaving is improved. Also, the life of the trim blade is improved. In particular, it is economical because only the required part needs to be shaving processed and the device set up. Moreover, since it is possible to prevent the occurrence of shoulder sagging in an arbitrary portion, the degree of freedom of the product shape is increased.

According to the fourth aspect of the invention, since the shaved surplus is held in the slit, it is possible to smoothly process the work without hindering other work. Moreover, since the shaving with the trim blade is further facilitated, the shape accuracy of the shaving is improved and the life of the trim blade is also improved.

Further, if constituted as described in claim 5, since a normal progressive press machine can be used, it is more economical and the processing reliability is improved.

Further, when the trim blade is constructed as described in claim 6, not only the shaving accuracy becomes good, but also the shaving surplus can be easily pushed and securely held in the slit. .

[Brief description of drawings]

FIG. 1 is a plan view showing a plate-shaped material with a flange punched out by an embodiment of a press working method of the present invention.

FIG. 2 is a plan view showing a plate-shaped material in each pressing step when a flange is formed from the plate-shaped material according to an embodiment of the pressing method of the present invention.

FIG. 3 shows a plate-shaped material in a state where trim shaving is performed by a trim blade, and a conventional method by shaving after pressing, in comparison with the plate-shaped material in an embodiment of the pressing method according to the present invention. It is sectional drawing which shows the plate-shaped raw material in the state which formed the hole.

FIG. 4 is a perspective view of a flange formed by the pressing method of the present invention.

[Explanation of reference numerals] W plate material, h outer circumference, t shaving line, 11, 12, 13 slits, 21, 22, 23
Small hole, 31, 32, 33 extra thickness, 40 flange,
UD upper mold

Claims (6)

[Claims] 1. A press working method for punching a product of a predetermined shape from a plate-shaped material, by cutting a part of the contour of the product on the plate-shaped material before processing at a predetermined distance and in a predetermined width substantially in parallel. A first pressing step for forming at least one slit; a second pressing step for shaving along a part of the contour of the product while pushing the excess thickness into the slit; A pressing method comprising a third pressing step of cutting along the entire circumference. 2. The contour of the product is the outer shape of the product, and in the first pressing step, a part of the outer shape of the product is cut out by a predetermined width in parallel with a predetermined distance. At least one slit is formed, and in the second pressing step, shaving is performed along a part of the outer shape of the product while pushing the excess thickness into the slit, and in the third pressing step, The press working method according to claim 1, wherein the product is punched from the plate-shaped material by cutting along the entire circumference of the product. 3. In the first pressing step, a part of the contour of the product is shaving by a trim blade, and a predetermined distance between the part of the contour of the product and the slit is set to the first value. The distance is set to satisfy the condition that the cutting load of the plate-shaped material at the time of shaving by the trim blade in the pressing step is smaller than the deformation load of the plate-shaped material at the time of cutting in the third pressing step. The press working method according to claim 1 or 2, wherein. 4. The second press step is configured such that the extra thickness is left in the slit and is separated from the plate-shaped material in the third press step. The press working method according to 1, 2, or 3. 5. The first pressing step, the second pressing step and the third pressing step are configured to be performed simultaneously by a progressive die.
The pressing method according to 2, 3, or 4. 6. The trim blade has a cutting edge angle formed by a surface perpendicular to the plate-shaped material including a part of the outer shape of the product and a surface extending from the surface toward the outside of the slit, The press working method according to claim 3, 4 or 5, wherein the cutting edge angle is set to an acute angle.