JPH07112575B2 - Cylindrical drawing method - Google Patents

Description

The present invention relates to a drawing method for forming a cylindrical member from a metal plate, and the cylindrical member formed by the method of the present invention is
For example, it can be used as a case of an oil filter for automobiles.

[Conventional technology]

Conventionally, when forming a cylindrical member by drawing, a disk-shaped blank 100 was used as shown in FIG. Generally, in drawing, a mild steel plate is often used as a blank, but when drawing is performed using a disc-shaped mild steel blank in this way, the flange portion 201 of the product 200 after drawing is shown in FIG. The ear 202 as shown is generated.

Since the ear portion 202 is a part that is not necessary in the final product, the ear portion 202 must be removed by the conventional drawing method. In other words, there is a problem in that the ear portion 202 becomes scrap as shown by the diagonal lines in FIG. 2, and the material cannot be used efficiently.

The present inventors have examined the occurrence of the ears 202, when the blank is made of mild steel sheet, with respect to the rolling direction of the mild steel sheet, there is little extension in the 45 ° direction, and the rolling direction, and It was confirmed that there were many extensions in the direction perpendicular to the rolling direction. In other words, it was confirmed that the ears 202 are formed in the rolling direction (X direction in FIG. 2) of the rolled steel sheet as the blank 100 material and in the direction perpendicular to the rolling direction (Y direction in FIG. 2).

The rolling direction is the direction in which rolling is performed, and the direction perpendicular to the rolling direction is the direction in the material plane that is perpendicular to the rolling direction (plasticity and working,
Corona Publishing Co., Ltd., corresponding to the horizontal direction in the book issued on April 30, 1980; Reference Proceedings of the 54th Plastic Working Spring Lecture Proceedings, 1975.5.1
7-19 Tokyo).

[Problems to be solved by the invention]

 The present invention has been devised in view of the above points.

That is, paying attention to the fact that the generation direction of the ears 202 always occurs in a fixed direction in relation to the rolling direction X, and the shape of the blank 100 is made non-circular as shown in FIG. An object is to make the shape of the brim portion 201 close to a circle.

As described above, when the blank has a non-circular shape, the present inventors have noted that the blank can be formed most efficiently when the blank is cut and formed from the plate member.

That is, as shown in FIG. 4, when the blank 100 is punched from the rolled steel plate 50, if the blank 100 has a circular shape, substantially triangular scrap portions 110 are formed between the blanks 100. . Therefore, the present inventors have paid attention to reducing the scrap portion 110 as much as possible and making the shape of the blank 100 non-circular.

FIG. 5 shows a state where the blank 100 has a hexagonal shape, and FIG. 6 shows a state where the blank 100 has an octagonal shape.
Further, FIG. 7 shows a state in which the blank 100 has a dodecagonal shape.

As explained above, when forming a non-circular blank from a rolled steel sheet, the length from the center to the periphery of the blank should be long at the 45 ° direction with respect to the rolling direction.

Minimize the area of scrap portion 110 that occurs between each blank 100.

Both will be required.

FIG. 8 shows how much the size of the blank 100 in the direction of 45 ° with respect to the rolling direction can be taken in comparison with the case where the blank 100 has a circular shape. As shown in FIG. 8, it is recognized that the dodecagonal shape of the blank 100 is the most efficient. When the blank 100 has a hexagonal shape, it is desirable to cut and form a four-row or three-row blank from the plate member.

FIG. 9 shows respective cutout lines when the blank is punched from the rolled steel plate 50 and the blank has a round shape, a hexagonal shape, and a dodecagonal shape. As shown in FIG. 9, it is recognized that the dodecagonal blank shape reduces the width W of the rolled steel plate 50 as compared with the hexagonal blank.

Then, the present inventors made the shape of the blank a dodecagonal shape and tried drawing using the blank.

FIG. 10 shows a cylindrical upper portion 203 and a collar portion 201 of a member drawn from a dodecagonal blank. As shown in FIG. 10, when the blank 100 has a dodecagonal shape, it is recognized that the generation of the ears 202 as shown in FIG. 2 is suppressed.

That is, by forming the blank 100 into a non-circular shape, generation of the ears 202 due to the rolling direction of the rolled steel plate 50 is suppressed. However, as is clear from FIG. 10, it is not possible to make the shape of the collar portion 201 after drawing into a circular shape simply by making the shape of the blank non-circular.

When the present inventors made various studies on the cause of this, as shown in FIG. 11, over the circumferential direction of the blank,
It was recognized that the cause was that the amount of shrinkage deformation and the resistance to the deformation were not uniform. For example, in the corner portion 130, the pressure receiving area pressed by the pressing plate during drawing is larger than that of other portions. Further, in this corner portion 130, the range of deformation due to the diaphragm is also increased. That is, it is recognized that the resistance of the corner portion 130 is larger than the resistance of the middle portion 140. It is considered that due to the anisotropy due to this shape effect, the shape of the brim portion 201 as shown in FIG. 10 is formed.

[Configuration and operation]

In view of the above-described points, the present invention is such that, even if the blank has a non-circular shape, the shape of the flange after drawing is closer to a circular shape. Therefore, according to the processing method of the present invention, the pressing force of the pressing plate that presses and clamps the blank 100 at the time of drawing is made uneven in the circumferential direction of the blank.

That is, in a non-circular blank presser plate, a presser plate that faces a portion where the distance from the blank center point to the periphery of the blank is short, has a pressing force at a portion where the distance from the blank center point to the periphery of the blank is long. Adopt a structure that is larger than the pressing force of the plate.

There are the following means for varying the pressing force of the holding plate in the circumferential direction of the blank. As shown in FIG. 12, the frictional force can be varied by dividing the surface roughness of the pressing portion of the pressing plate 300 into a small surface roughness portion 301 and a large surface roughness portion 302. Friction resistance decreases in areas with a small surface roughness, whereas areas with large surface roughness 302
The frictional resistance at will increase. Therefore, for example, when the blank has a dodecagonal shape, the portion having the small surface roughness faces the corner portion 130, and the portion 302 having the large surface roughness faces the intermediate portion 140 of the dodecagonal blank.

FIG. 13 shows another example. In this example, the holding plate 30
The lubricant is partially applied to 0. That is, the friction resistance is small in the portion 311 coated with the lubricant, and the friction resistance is large in the portion 312 not coated with the lubricant.

FIG. 14 shows still another example. In this example, the holding plate 30
A beat forming protrusion 330 is formed at 0. At the portion pressed by the bead forming protrusion 330, the blank 100 is drawn by the bead forming protrusion 330 while being bent and deformed. That is, because of the resistance required to cause bending deformation, the resistance to diaphragm deformation (shrink flange deformation) increases at the portion where the bead forming protrusion 330 is present.

FIG. 15 shows still another example. In this example, the holding plate 30
A protrusion 341 and a groove 342 are formed on the pressing surface of 0.
According to the example shown in FIG. 15, the holding plate 300 presses and holds the blank 100 only on the protruding side 341.

In the present invention, the pressing and pinching force of the pressing plate is made a means to make it non-uniform over the circumferential direction of the blank, and various modifications other than the above can be adopted. Considering the excellent stability and the easy adjustment of the resistance, the example shown in Fig. 15 was adopted.

As shown in FIG. 15, a protrusion is provided on the holding surface 380 of the holding plate 300.
341 was formed, and the drawing process was performed thereby.

Next, this drawing process will be described with reference to FIG.

As described above, the blank 100 formed in a non-circular shape, for example, a dodecagonal shape is clamped at its peripheral portion by the holding plate 300 and the die 400. A cylindrical mold space 410 into which the punch 500 can be fitted is formed in the center of the die 400. Presser plate 300
Receives a pressing force P _C from a pneumatic device (not shown) via the bar 390 and presses the blank 100 toward the die 400.

In this way, after the peripheral portion is sandwiched between the die 400 and the pressing plate 300, the punch 500 is displaced to the die space 410 side of the die 400.

Due to the displacement of the punch 500, the central cylindrical portion of the blank 100 is formed by drawing. Further, the collar portion 201 remains in the portion sandwiched by the holding plate 300 and the die 400. Here, the brim holding force is non-uniform in the circumferential direction of the blank, and the blank 100 also has a non-circular shape and its deformation resistance is non-uniform in the circumferential direction. Ten
The shape effect of 0 and the change in the pressing force of the pressing plate cancel each other out, so that the brim portion 201 can have a substantially circular shape.

〔Example〕

Next, specific examples of the processing method of the present invention will be described. In the embodiment, a rolled steel sheet of mild steel is used as the blank. The blank has a dodecagonal shape as shown in FIG. 9 and is formed by punching two rows from the rolled steel plate 50.
Further, the holding plate 300 has a shape as shown in FIG. 15, and the pressure receiving surface 380 of the holding plate 300 is formed with a projection 341. The protrusion height H of the protrusion 341 is about 0.04 mm. Moreover, the pressing force Pc of the holding plate 300 is 4 to 8 tons.
Give some pressure. And the thickness of the blank 100 is 0.4 mm
The degree.

In the embodiment, the blank 100 has the shape of
In addition to the dodecagonal shape as shown in the figure, the one having the arcuate portion 131 formed at the corner portion 130 as shown in FIG. 24 is also used. In this example, the aperture diameter D is set to 10 as shown in FIG.
The width W is set to about 0 mm, and the blank 100 for that purpose has a width W of about 167 mm. In addition, the second
The radius R of the arc portion 131 shown in FIG. 4 having 15 mm, 30 mm and 45 mm was also used together. Assuming that the blanks of the respective shapes described above were drawn by the apparatus shown in FIG. 1 and subjected to simulation calculation, the effect of the arc portion 131 formed on the corner portion 130 was as shown in FIG. was gotten.

FIG. 17 shows the ratio of the aperture diameter D to the radius of curvature R of the corner 131 on the horizontal axis. The vertical axis in FIG. 17 shows the minimum diameter Dmin of the outer periphery of the collar portion 201 and the difference between the minimum diameter and the maximum diameter. As shown in FIG. 17, when the radius of curvature R of the corner portion 130 is set to 0, in other words, when the arc portion is not formed in the corner portion, the corner portion 130
The minute protrusions 133 will be left on. On the other hand, the corner 130
It is understood that when the arcuate portion 131 having the radius of curvature R of about 30% of the aperture diameter D is formed, the outer periphery of the flange portion 201 becomes substantially circular. As is clear from the experimental results shown in FIG. 17, when the arcuate portion 131 is formed at the corner 130, the radius of curvature R of the arcuate portion 131 is about 25% to 40% of the aperture diameter D. Is desirable.

In this example, the holding surface 380 of the holding plate 300 shown in FIG.
The drawing process was performed by variously changing the ratio of the protruding portion 341 to the groove portion 342 in FIG. That is, the width w of the protrusion 341 is 20%, 40%, 60% of the total width Wt of the protrusion 341 and the groove 342.
%, 80% and 100%. W / Wt is 1
The state of 00% indicates that the pressing force on the pressing surface 380 of the pressing plate 300 is uniform over the entire circumference in the circumferential direction. The experimental results of this diaphragm are shown in FIGS. 18 to 20. In each figure, the horizontal axis represents the resistance addition width ratio w / Wt, and the vertical axis represents the minimum diameter Dmin of the outer periphery of the collar portion 201 and the difference between the minimum diameter and the maximum diameter. In addition, FIG. 18 shows the arc portion 1 at the corner portion 130 of the blank.
In the state in which 31 is not provided, in FIG. 19, the arc portion 131 is provided in the corner portion 130, and the ratio of the radius of curvature R to the aperture diameter D is set to 15%. In FIG. 20, the radius of curvature R and the aperture diameter D are shown. The ratio of 30%
Indicates the state. As is commonly recognized from all the examples of FIGS. 18, 19, and 20, the minimum diameter Dmin can be increased in all of the examples in which the pressing plate 300 is provided with the protrusions 341. It is also recognized that the difference between the maximum diameter and the minimum diameter fluctuates depending on the ratio of the protrusion width. The difference between the maximum diameter and the minimum diameter indicates how far the outer circumference of the collar portion 201 deviates from the true circle, and the smaller the difference, the more desirable.

As shown in FIG. 18, it is desirable that the projections occupy about 20% to 70% in the state where no arc portion is provided at the corner portion of the blank. Further, as shown in FIG. 19, when the arcuate portion 131 having a curvature radius of about 15% with respect to the aperture diameter D is provided, it is desirable that the proportion of the protrusions is about 50 to 70%.
Further, as shown in FIG. 20, the ratio to the aperture diameter D is 30
For a blank using the arcuate portion 131 having a radius of curvature of about%, it is desirable that the proportion of the protrusions is about 50 to 85%.

The common selection from the above embodiments is that the holding plate 302
Means that it is necessary to form protrusions 341 and make the pressing force uneven. The proportion of the protrusions 341 is preferably about 40 to 80%, and is most preferable when the proportion of the protrusions 341 is about 50 to 60%.

Based on the results of the above implementation, in this example, the blank 10
The shape of 0 is basically a dodecagonal shape, and the arc portion 341 has a radius of curvature R whose ratio to the aperture diameter D is 30% at the corner portion.
To form. Then, the pressing force Pc of the pressing plate 300 is set to 8 tons, and the projecting portion 341 is further formed on the pressing plate 300.
Drawing was carried out using the one in which the ratio of 341 was 60%. FIG. 22 shows the circumferential change of the inner diameter of the cylindrical upper portion of the product 200 drawn based on such specifications. As shown in FIG. 22, according to the drawing process of this example, the roundness of the product 200 can be increased to 0.07.
This is a product 200 that uses a round blank as shown in FIG.
The roundness is significantly improved compared to the roundness of 0.17. The product shown in FIG. 21 is formed by the conventional method shown in FIG.

Next, a case where the product 200 drawn by the method of the present invention is used as a case of an oil filter for an automobile will be described. In this case, a blank 100 is processed from a strip-shaped plate as shown in FIG. 23, and this is first drawn. The drawing process of the present invention is applied to the blank 100 from the first process.
This is a drawing method up to drawing. That is, the first stop is performed by the method of the present invention. After that, the cylindrical portion is deepened further by the second and third drawing steps, and after the third drawing is performed, the flange portion 280 is formed. Then flange 2
Cut around 80 and arrange the shape.

〔The invention's effect〕

As described above, according to the drawing method of the present invention, by making the shape of the blank non-circular, the shrinkage flange deformation resistance of the blank during drawing becomes uneven in the circumferential direction due to the shape effect of the blank. . On the other hand, the clamping force of the pressing plate that clamps the blank at the time of drawing is made non-uniform in the circumferential direction so as to supplement the above-described blank shape effect.

As a result, in the drawing method of the present invention, when a blank is drawn into a cylindrical shape, it is possible to obtain a cylindrical product of the same size from a smaller number of materials than a round blank when drawn by a conventional method. Have.

[Brief description of drawings]

FIG. 1 is a block diagram showing an apparatus used in the method of the present invention, FIG. 2 is a front view showing the shape of a member formed by conventional drawing, and FIG. 3 is an explanatory view explaining the concept leading to the present invention.
FIG. 4 is an explanatory view showing a blank forming method in a conventional processing method, FIGS. 5 to 7 are explanatory views showing a blank forming method according to the present invention, and FIG. 8 is a blank shape and a 45 ° dimensional ratio. FIG. 9 is an explanatory view showing a blank forming method according to the present invention, FIG. 10 is an explanatory view showing a shape of a collar portion of a dodecagonal blank after drawing, and FIG. Explanatory diagram showing the state of drawing of a rectangular blank, FIGS. 12 to 15 are explanatory diagrams showing each example of the structure of the holding plate according to the present invention, and FIG. 16 is an explanatory diagram showing a conventional machining method. FIGS. 17 and 18 are explanatory views showing the effect of the radius of curvature of the arc upper portion formed in the corner portion of the dodecagonal blank, FIGS.
FIG. 20 is an explanatory diagram showing the relationship between the ratio of the protrusions of the pressing plate and the minimum diameter, FIG. 21 is an explanatory diagram showing the circularity of the upper part of the cylinder obtained by the conventional drawing method, FIG. 22 Is an explanatory view showing the roundness of the upper part of the cylinder obtained by the drawing method according to the present invention, FIG. 23 is a cross-sectional view showing each step in forming an oil filter case using the drawing method of the present invention, The figure shows a front view of a dodecagonal blank,
FIG. 25 is a perspective view showing the product after drawing. 100 …… Blank, 200 …… Product cylinder, 300 …… Presser plate, 34
1 …… Projection, 342 …… Groove, 400 …… Die, 500 …… Punch.

Claims (8)

[Claims] 1. A first step of forming a non-circular plate-shaped blank from a metal plate member, a second step of sandwiching the peripheral portion of the blank by a holding plate and a die, and a punch in the central portion of the blank. Arranging the punch and displacing the punch in the direction in which the die is arranged to form a cylindrical squeezing portion in the central portion of the blank. The pressing force against the blank is characterized in that a portion of the blank where the distance from the central portion to the peripheral portion is short is made larger than a portion where the distance from the central portion to the peripheral portion is long. . 2. The cylindrical drawing method according to claim 1, wherein, in the first step, the blank has a regular dodecagonal shape. 3. The cylinder according to claim 1, wherein, in the first step, the blank is basically a regular dodecagonal shape, and the peripheral corners are formed in an arc shape. Drawing method. 4. The radius of the circular arc portion formed on the peripheral portion of the blank is 30% of the radius of the upper portion of the cylinder in the third step.
The cylindrical drawing method according to claim 3, characterized in that the size is about the same. 5. In the second step, a protrusion and a groove are formed on a surface of the pressing plate that comes into contact with the blank, and the protrusion has a distance from a central portion to a peripheral portion of the blank. The cylindrical drawing method according to claim 1, wherein the groove portion is arranged so as to abut on a short portion, and the groove portion is arranged to face a portion of the blank having a long distance from the center to the periphery. 6. In the second step, the ratio of the protrusions of the pressing plate to the total pressing area of the pressing plate is 40%.
Claim 5 is characterized in that it is approximately 80%.
The cylindrical drawing method according to item. 7. In the second step, the ratio of the protrusions of the pressing plate to the total pressing area of the pressing plate is 50%.
Claim 5 is characterized in that it is about 60%.
The cylindrical drawing method according to item. 8. The cylindrical drawing method according to claim 1, wherein the second step and the third step are performed at the same time.