JP2000225421A - Method for forming hemispherical protrusions and bosses - Google Patents

Abstract

(57) [Problem] To provide a method for reliably forming a hemispherical projection having the same thickness as a plate material over the entirety by press working, and to make the thickness of a cylindrical wall substantially the same as the plate material over the entirety. In addition, a method is provided for reliably forming a boss having a relatively large height in the cylinder center direction. An annular recess 9 is formed at a predetermined position in a plate 1 by compression processing, and a material corresponding to the formation of the recess 9 in the plate 1 is caused to flow inward of the recess 9.
The material flow force pushes up a portion of the plate material 1 on the inner side of the concave portion 9 to form the hemispherical projection 14. The boss portion 41 is formed by pushing up a predetermined portion of the plate 1 by the material flow force when the concave portion 34 is formed by the compression process to form the spherical bulge portion 33, and then performing the compression process at least twice. The inner portion is sequentially pushed up by the material flow force of the compression process to sequentially form the protruding portion 37 and the headed tubular body portion 39, and the top surface portion 39b of the headed tubular body portion 39 Through a step of forming a through hole 39c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a hemispherical projection and a boss on a part of a plate by press working.

[0002]

2. Description of the Related Art Heretofore, as a means for forming a hemispherical projection on a part of a plate material, there has been known a forming method of performing an overhanging process or a drawing process. For example, a conventional method of forming a hemispherical projection by overhanging is generally performed through a process as shown in FIG. That is, first, the periphery of the portion where the hemispherical projection is to be formed in the plate-shaped workpiece 1 is sandwiched and restrained from above and below by the die 2 and the wrinkle retainer 3. Next, the lower punch 4 having a spherical tip is inserted into the hollow portion 7 of the die 2 while pressing and deforming the plate material 1 from below. By this press working,
A hemispherical projection 8 having a shape corresponding to the tip shape of the lower punch 4 is formed on the plate material 1 by being stretched by the application of a tensile stress. FIG. 9 shows the plate member 1 in which the hemispherical projection 8 is partially formed by the above-mentioned forming process.

On the other hand, as a means for forming a boss portion on a part of a plate material, a molding method of subjecting a plate material to burring is generally known (see Japanese Patent Application Laid-Open No. 62-214834). When a boss having a predetermined diameter and a relatively large height in the cylinder center direction is formed, the boss is generally processed in the process order shown in the process explanatory diagram of FIG. FIG. 10 illustrates, for example, a step of forming a flange that is used by welding with a motor frame or a pipe that is inserted through a boss portion with a motor frame or a pipe inserted through a boss portion with a motor shaft inserted through the boss portion. It is.

FIG. 1A shows a plate-shaped workpiece 1 serving as a base material for forming a boss portion at a predetermined position.
By drawing or bulging,
The material is drawn from the periphery to the position where the boss is to be formed, and a hemispherical projection 10 having a diameter larger than the diameter of the boss to be formed is formed in advance as shown in FIG. This hemispherical projection 10 is a plate material 1 necessary for obtaining a boss of a desired shape.
Is formed in advance in order to secure a volume.

[0005] Next, the hemispherical projection 10 is reduced in diameter so as to draw the material further inward by repeating drawing, and as shown in FIG. It is a headed cylindrical projection 11 integrally having a cylindrical portion 11a and a top surface portion 11b having the same diameter as the diameter. Furthermore, on the top surface 11b of the protrusion 11,
As shown in (d), a perforation process is performed to open the through hole 11c. Finally, as shown in (e), by performing burring on the protruding portion 11, a boss portion 12 having a desired cylindrical shape having a short dimension in the cylinder center direction is formed.

[0006]

However, according to the conventional means for forming the hemispherical projection 8 on a part of the plate 1, the tensile stress at the time when the portion of the plate 1 where the hemispherical projection 8 is to be formed is formed. The hemispherical projection 8 thus formed has a thickness smaller than the thickness of the plate material 1,
It results in a thin plate with insufficient strength. In addition, the base plate thickness t1, the plate thickness t2 near the top, the plate thickness t3, and the plate thickness t0 of the plate 1 shown in FIG.
Is such that t0>t3>t2> t1, and the nonuniformity of the plate thicknesses t1 to t3 of the respective portions of the hemispherical projection 8 is such that the hemispherical projection 8 is further formed and, for example, a boss portion is formed. It adversely affects the post-process when molding.

On the other hand, in the conventional means for forming the boss portion 12 on a part of the plate material 1, drawing is performed on the hemispherical projection 10 shown in FIG. 1B by using a mold substantially similar to that shown in FIG. By doing so, in the process of forming the protruding portion 11 shown in (c), the portion where the boss portion 12 is to be formed is subjected to tensile stress in each step of reducing the diameter, and the plate thickness is gradually reduced. (E) boss 1 formed through such a process
The thickness t4 of the second cylindrical wall is necessarily considerably smaller than the thickness of the plate material 1. Moreover, the height h of the boss portion 12 in the cylinder center direction is h.
When it is desired to increase the thickness, it is necessary to perform ironing at the time of burring.
Becomes even thinner. However, for example,
In the above-described motor frame, a boss having a predetermined diameter, a relatively high height h in the cylinder center direction, and a plate thickness equivalent to that of the plate 1 is required. It is difficult to form by a conventional molding method.

In view of the above, the present invention has been made in view of the above-mentioned conventional problems, and a method for surely forming a hemispherical projection having substantially the same thickness as a plate material over the entirety by pressing is provided. It is an object of the present invention to provide a method capable of reliably forming a boss portion having a plate thickness substantially the same as a plate material as a whole and having a relatively large height in a cylindrical direction.

[0009]

To achieve the above object, a method for forming a hemispherical projection according to a first aspect of the present invention is to form an annular concave portion at a predetermined position in a flat plate material, The compression process is performed so that the material corresponding to the formation of the concave portion in the material flows inward of the concave portion, thereby pushing up the portion of the plate material on the inner side of the concave portion by the material flow force of the material. As a result, hemispherical projections were formed.

In this method of forming a hemispherical projection, the compression work is performed without using a tool such as a punch for forcibly pushing up and spreading the plate material, so that the recess is formed inwardly. A predetermined portion of the plate is pushed up by the material flow force to form a hemispherical protrusion, and since the material flow force is a compressive stress, the formed hemispheric protrusion is reduced in thickness relative to the original plate. Does not occur, and has the same thickness as the thickness of the plate material over the whole.

According to a second aspect of the present invention, in the method of forming a hemispherical protrusion, an annular concave portion is formed at a predetermined position in a flat plate material, and a material corresponding to the formation of the concave portion in the plate material is formed in the concave portion. By performing a compression process so as to cause the material to flow inward, the material flowing force of the material causes the inner portion of the recess in the plate to be pushed up, so that the diameter is larger than the diameter of the hemispherical projection to be formed. A bulging portion forming step of forming a spherical bulging portion having a large diameter, and reducing the bulging portion to a predetermined diameter by performing the same compression processing as the compression processing on the outer peripheral portion of the bulging portion. And forming a hemispherical protrusion by deforming the material so as to push up the bulging portion with a material flowing force inward of the material corresponding to the formation of the reduced diameter to form a hemispherical protrusion. Have.

According to this method of forming a hemispherical projection, the same effect as that of the first invention can be obtained, and in addition, a spherical bulge having a diameter larger than the diameter of the hemispherical projection to be formed is formed. After being formed in advance by compression, the outer periphery of the bulging portion is further compressed to form a desired hemispherical projection, so that the material can flow from a wide area of the plate to a predetermined location. Thereby, since the concave portion formed around the hemispherical protrusion can be made small in depth,
Strength reduction can be suppressed. In addition, since the material flow of the plate material is divided into two compression processes, and the spherical protruding portion is reduced in diameter and pushed up by the material flow force to have a predetermined protruding height, the formation of the hemispherical protruding portion is performed. It can be performed smoothly compared to the case of forming all at once in one compression step.

According to a third aspect of the present invention, in the method for forming a hemispherical projection, an annular concave portion is formed at a predetermined position in a flat plate material, and a material corresponding to the formation of the concave portion in the plate material is formed. By performing a compression process so as to cause the material to flow inward, the material flowing force of the material causes the inner portion of the recess in the plate to be pushed up, so that the diameter is larger than the diameter of the hemispherical projection to be formed. A bulging portion forming step of forming a spherical bulging portion having a large diameter, and the outer peripheral portion of the bulging portion is subjected to the same compression processing as the compression processing to reduce the diameter of the bulging portion. A diameter reducing step of deforming the swollen portion so as to push up the bulging portion by a material flowing force inward of the material corresponding to the formation of the diameter reducing portion, and repeating the diameter reducing step a plurality of times to form a cylindrical portion. A hemispherical projection with the top closed by a hemispherical part To.

According to this method of forming a hemispherical projection, a hemispherical projection having a large protruding height from the plate material and having the same thickness as the thickness of the plate material over the entirety can be formed. Since the material flow is divided into a plurality of compression processes, the hemispherical projection can be formed more smoothly.

[0015] In a fourth aspect of the present invention, a method of forming a boss portion includes forming an annular concave portion at a predetermined position in a flat plate material,
By performing a compression process so that a material corresponding to the formation of the concave portion in the plate material flows inward of the concave portion, a portion of the plate material on the inner side of the concave portion due to a material flowing force of the material. Bulging portion to form a spherical bulging portion having a diameter larger than the diameter of the boss portion to be formed, and compressing the outer peripheral portion of the bulging portion in the same manner as the compressing process. And reducing the diameter of the bulging portion, and deforming the bulging portion so as to push up the bulging portion by a material flowing force inward of the material corresponding to the formation of the diameter of the bulging portion. A projecting portion forming step of forming a projecting portion having a shape in which the projecting portion is closed by a hemispherical portion; The hemispherical part Forming a top surface portion that is flattened by being compressed in the direction of the center of the cylinder, forming a headed cylinder portion having a head portion having the cylinder portion and the top surface portion, and a boring process on the top surface portion. And forming a boss portion.

In this method of forming the boss portion, the material flow at the time when the concave portion is formed by performing the compression working without using any tool such as a punch for pressing and forcibly spreading the plate material. After pressing up a predetermined portion of the plate material by force to form a spherical bulge, the diameter is repeatedly reduced to a predetermined diameter every time compression processing is performed at least twice, and the inner portion is pressed by the material flow force by the compression processing. Are sequentially pushed up to sequentially form the protruding portion and the headed cylindrical body portion. Since the material flow force is a compressive stress, the material can be pushed up without causing a decrease in the thickness of the plate material and the height of protrusion from the plate material can be accurately set to a large predetermined value. Therefore, the molded boss part
In addition to having the same thickness as the thickness of the plate material throughout, the protrusion height from the plate material is an accurate predetermined value.

According to a fifth aspect of the present invention, there is provided a method of forming a boss portion, wherein an annular concave portion is formed at a predetermined position in a flat plate material,
By performing a compression process so that a material corresponding to the formation of the concave portion in the plate material flows inward of the concave portion, a portion of the plate material on the inner side of the concave portion due to a material flowing force of the material. Bulging portion to form a spherical bulging portion having a diameter larger than the diameter of the boss portion to be formed, and compressing the outer peripheral portion of the bulging portion in the same manner as the compressing process. And reducing the diameter of the bulging portion, and deforming the bulging portion so as to push up the bulging portion by a material flowing force inward of the material corresponding to the formation of the diameter of the bulging portion. In the protruding portion forming step of forming a protruding portion having a shape closed by a hemispherical portion, and in any of the pre-process of the bulging portion forming process or the post-process of the protruding portion forming process, A predetermined portion of the plate material or a hemispherical portion of the protruding portion A perforation step of forming a through hole in any of them, and a final step of enlarging the through hole to form a boss by expanding the protrusion having the through hole in the hemispherical portion. Have.

According to this method of forming the boss portion, in addition to obtaining the same effect as the fourth invention, in addition to the fact that the hemispherical portion having the through hole extends to the projecting portion in which the top of the cylindrical portion is closed, the flange is formed. By performing the processing, the boss portion can be formed at a stroke while enlarging the through hole, so that the process can be simplified. In addition, if a through hole is formed in a flat plate material before processing, drilling can be easily performed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 (a)-
(C) shows a working process according to an embodiment of the method for forming a hemispherical projection of the present invention. (A) shows a flat plate-shaped workpiece 1 before processing, and in the present invention, compression processing is performed on a predetermined portion of a peripheral portion 1b of a central portion 1a of the plate 1 where a projection is to be formed. A ring-shaped concave portion 9 is formed in the peripheral portion 1b as indicated by a two-dot chain line, and almost all of the material corresponding to the formation of the concave portion 9 flows into the central portion 1a on the inner side of the concave portion. As a result, as shown in a vertical cross-sectional view after the compression working and in a perspective view (c), a ring-shaped recess 9 is formed in the peripheral portion 1b by the compression working and the plate material 1 is formed. A hemispherical projection 14 is formed in the central portion 1a by being pushed up from the periphery by a material flow force of a material corresponding to the formation of the concave portion of the peripheral portion 1b.

FIG. 2 is a longitudinal sectional view showing the steps of the compression working in the molding method. In the figure, first, an outer portion of a portion of the plate material 1 on which the concave portion 9 is to be formed,
A die 17 having a flat supporting surface and a hollow portion 18
With the wrinkle presser 18 having a, it is sandwiched and restrained from above and below. In this state, the hemispherical projection 1 to be formed
4, a cylindrical punch 19 having a hollow portion 19a having an inner diameter equal to the outer diameter is pressed against the peripheral portion 1b of the plate 1 through the hollow portion 18a of the wrinkle retainer 18, and the concave portion 9 is formed by this compression processing. .

At the time of the above-mentioned compression working, the outside of the concave portion 9 in the plate 1 is strongly sandwiched between the die 17 and the wrinkle holder 18 to prevent the material from flowing, and the concave 9 in the plate 1 is formed. The inner side of the portion to be formed has a free surface that allows material flow due to the presence of the hollow portion 19a of the punch 19. Therefore, the concave portion 9 in the plate 1
Almost all of the material corresponding to the formation of (1) flows inwardly, so that the central portion 1a of the plate 1 is pushed up by this material flow, and the hemispherical projections 14 are formed at once.

In this embodiment, the support surface (upper surface) of the die 17 used in the compression step has a flat shape, and the central portion 1a of the plate material 1 is pressed against the die 17 while being forcibly expanded. Without using any tool such as a lower punch, the central portion 1 is formed by the force of the material flowing inward when the concave portion 9 is formed by performing the compression processing by the punch 19.
a is pushed up to form a hemispherical protrusion 14, and since the material flow force is a compressive stress, the formed hemispherical protrusion 14 is formed.
Does not cause a decrease in the thickness of the plate material 1. That is, FIG.
The relationship among the thickness t1 at the base of the projection 14, the thickness t2 near the top, the thickness t3 at the top, and the thickness t0 of the plate 1 shown in (b) is t0 = t3 = t2 = t1.

When the depth of the concave portion 9 is increased by increasing the compression amount of the peripheral portion 1b of the plate member 1, the plate thickness t1 of the base of the projection 14 is increased by the wall thickness phenomenon. Larger than.

FIGS. 3A and 3B are longitudinal sectional views showing a forming process according to another embodiment of the method for forming a hemispherical projection of the present invention. First, a bulging portion 21 having a spherical surface having a diameter larger than a predetermined diameter of a hemispherical projection to be formed as shown in FIG. This compression processing is performed using a mold having substantially the same structure as that shown in FIG. 2 and having different dimensions.
A ring-shaped recess 20 having a large outer diameter is formed. Since the bulging portion 21 is formed by pushing up the central portion 1a of the plate 1 by the material flow force at the time of the compression working, it has the same plate thickness as the plate 1 as a whole.

Next, as shown in (a), a cylindrical punch having a hollow portion 22a having the same inner diameter as the diameter of the hemispherical projection to be formed and having the same outer diameter as the outer diameter of the concave portion 20 is formed. 22
And the die 17 having a flat support surface, the outer peripheral portion of the bulging portion 21 is compressed. As a result, the diameter of the bulging portion 21 is reduced to the same predetermined diameter as that of the hemispherical projection to be formed, and the material of the outer peripheral portion of the bulging portion 21 flows inward to further bulge the bulging portion 21. Push up,
As shown in (b), a hemispherical projection 23 having a predetermined diameter and a projection height is formed, and a wide ring-like shape having a smaller inner diameter than the recess 20 is formed on the outer periphery of the projection 23. Is formed.

In this method of forming the hemispherical projection 23, the die 17 is pressed twice without using a tool such as a lower punch for pressing the central portion of the plate material 1 to forcibly push it up. The processing is performed sequentially, and the central portion 1a of the plate material 1 is sequentially pushed up by the material flow force of the material corresponding to the formation of the concave portions 20 and 24 formed at that time, and finally a desired hemispherical shape is obtained. A projection 23 is formed. Therefore, the thickness of the formed hemispherical protrusion 23 does not decrease with respect to the thickness of the plate material 1 over the entirety.

Moreover, in the above-mentioned forming method, two compression processes are required, but the material is transferred from the central portion 1a to the peripheral portion 1b of the plate material 1 from a wider area than in the embodiment.
Can be made to flow. Therefore, the concave portion 24 formed around the protrusion 23 has a smaller depth than that of the embodiment, and has an advantage that a reduction in strength can be suppressed. In addition, the material flow of the plate 1 is divided into two compression processes, and the spherical protruding portion 21 is pushed up by the material flow force while reducing the diameter thereof to have a predetermined protruding height.
Can be more smoothly performed as compared with the case where the molding is performed at once by a single compression step.

FIG. 4 is a process explanatory view sequentially showing a molding process according to still another embodiment of the method for molding a hemispherical projection of the present invention. FIG. 1A shows a plate-shaped workpiece 1 serving as a base material for forming a hemispherical projection.
As shown in (b), a bulged portion 27 having a spherical surface having a considerably larger diameter than the hemispherical projection to be formed is formed in the central portion 1a by compression. This compression processing is performed using a mold having substantially the same structure except that the dimensions are different from those shown in FIG.
A ring-shaped recess 28 having a smaller depth and a larger inner and outer diameter than that of FIG. Since the bulging portion 27 is formed by compressive stress by pushing up the central portion 1a of the plate material 1 by the material flow force by the compression processing, the bulged portion 27 has the same plate thickness as the plate material 1 throughout.

Next, the bulging portion 27 is reduced in diameter by compressing the outer peripheral portion of the bulging portion 27 on the plate material 1 on which the bulging portion 27 is formed, as shown in FIG. A hemispherical protrusion 29 slightly larger in diameter than a hemispherical protrusion having a desired diameter to be formed is formed. At this time, the hemispherical protrusion 29
The material at the outer peripheral portion of the bulging portion 27 flows inward, and the material flow force acts to push up the bulging portion 27 and is formed. On the outer periphery of the hemispherical projection 29, a wide ring-shaped recess 30 having an inner diameter smaller than that of the recess 28 is formed. In forming the hemispherical projection 29, the die is subjected to compression without any tool such as a lower punch for forcibly spreading and pushing up the central portion 1a of the plate material 1 on the die side. Due to the material flow force when the diameter of the portion 27 is reduced, the central portion of the bulging portion 27 is further pushed up to form a hemispherical projection 29. Therefore, the thickness of the formed hemispherical projection 29 does not decrease relative to the original plate 1, and conversely, the thickness t4 of the base of the hemispherical projection 29 significantly increases compared to the thickness of the plate 1. Have been.

Finally, the outer periphery of the hemispherical projection 29 is further compressed on the plate 1 on which the hemispherical projection 29 is formed, thereby reducing the diameter of the hemispherical projection 29.

This compression working is performed by using a mold having substantially the same structure as that shown in FIG. As a result, the material at the outer peripheral portion of the hemispherical protrusion 29 flows inward, and the material flow force acts to further push up the protrusion 29, and as shown in FIG.
A hemispherical protrusion 31 is formed in a shape in which the apex of a is closed by a hemispherical portion 31b. On the other hand, a ring-shaped concave portion 32 having an inner diameter smaller than the concave portion 30 and wider than the concave portion 30 is formed on the outer periphery of the protrusion 31.

In the method of forming the hemispherical projection 31 according to this embodiment, no tool such as a lower punch is used on the die side for forcibly expanding and pushing up the central portion 1a of the plate material 1. Then, the diameter reduction is repeated every time the compression processing is performed three times in total, and the bulging portion 27 and the hemispherical protrusion 29 are sequentially pushed up by the material flow force at that time to have a predetermined protrusion height. Therefore, the hemispherical protrusion 31 having a large protruding height from the plate 1 can be formed, and the hemispherical protrusion 31 does not cause a decrease in the thickness of the plate 1, and has a thickness substantially equal to the plate thickness of the plate 1. Have evenly throughout. In addition, the thickness t5 of the base of the protrusion 31 is slightly larger than the thickness of the plate 1. In addition, since the material flow is divided into three compression processes, there is an advantage that the final hemispherical projection 31 can be formed more smoothly.

FIG. 5 is a process explanatory view sequentially showing a forming step according to an embodiment of the method of forming a boss portion of the present invention. FIG. 1A shows a plate-shaped workpiece 1 serving as a base material for forming a boss portion, and a central portion 1 of the plate 1.
In (a), as shown in (b), a spherical bulge 33 having a diameter considerably larger than the boss to be formed is formed by compression. At this time, a ring-shaped concave portion 34 having a relatively small depth and a large inner and outer diameter is provided around the bulging portion 33.
Is formed. As described in the method of forming each of the hemispherical projections 14, 23, 31 described above, the bulging portion 33 is formed by the compressive stress by pushing up the central portion 1a of the plate 1 by the material flow force by the compression processing. Therefore, the same thickness as the plate material 1 is provided throughout.

Next, with respect to the plate material 1 on which the bulging portion 33 is formed, the outer peripheral portion of the bulging portion 33 is subjected to compression to reduce the diameter of the bulging portion 33, as shown in FIG. A protruding portion 37 is formed in which the top of a cylindrical portion 37a slightly larger in diameter than the desired boss to be formed is closed by a hemispherical portion 37b. At this time, the protruding portion 37 is formed such that the material of the outer peripheral portion of the protruding portion 33 flows inward and pushes up the protruding portion 33, so that the protruding height from the plate 1 becomes larger than the protruding portion 33. A wide ring-shaped recess 38 having an inner diameter smaller than that of the recess 34 is formed on the outer periphery of the protrusion 37. As is apparent from the above description, not only does the thickness of the protruding portion 37 not decrease over the entire thickness of the plate 1, but also the thickness of the base of the protruding portion 37 is slightly larger than the thickness of the plate 1. .

Subsequently, by compressing the outer peripheral portion of the projecting portion 37, the diameter of the projecting portion 37 is reduced, and as shown in (d), the projecting portion 37 has the same predetermined diameter as the boss portion to be formed. A cylindrical portion 39a and a hemispherical portion 37b
Is flattened by compressing in the direction of the center of the cylindrical portion 39a to form a top surface portion 39b, thereby obtaining a headed cylindrical head portion 39 having a cylindrical portion 39a and a top surface portion 39b. . At this time, the inner diameter of the recess 38 is slightly reduced to form a wide ring-shaped recess 40.

Incidentally, the method of forming the boss portion of the present invention is as follows.
Particularly, the present invention does not have a feature in a process using a new mold, but has a feature in a series of continuous processes. Therefore, the process of forming the headed cylindrical body portion 39 from the above-mentioned protruding portion 37 is as follows.
This is performed using a well-known mold, for example, the protrusion 3
7, a die having a protrusion for defining the inner diameter of the headed cylindrical body portion 39, and the headed cylindrical body portion 3 to be formed.
9 and a punch having a recess for defining the outer shape.

Further, as shown in (e), a hole 39c is formed in the center of the top surface portion 39b of the headed cylindrical body portion 39 by drilling. Finally, a well-known sizing process is performed on the top surface portion 39b having the through hole 39c to form the boss portion 41 having a desired shape as shown in FIG. The sizing process is a process of forming the inner diameter side of the boss shape, and may be omitted if it is not necessary for product use. In that case, the headed tubular body portion 39 becomes a desired boss portion.

In the method of forming the boss portion 41 of this embodiment, the compression is mainly performed without using any tool such as a lower punch for pushing up the central portion 1a of the plate 1 while forcibly spreading it to the die side. The bulging portion 33, the protruding portion 37, the headed tubular portion 39, and the boss portion 41 are sequentially formed by performing the deforming process so as to push up by the material flow force at that time while sequentially reducing the diameter by repeating the processing. ing. Therefore, the material can be pushed up without causing a decrease in the thickness of the plate 1 and the height of the protrusion from the plate 1 can be accurately set to a large predetermined value. Therefore, the formed boss 4
1 has a plate thickness substantially equal to the plate thickness of the plate material 1 over the whole, and the protrusion height from the plate material 1 becomes an accurate predetermined value.

FIGS. 6 (a) to 6 (e) are process explanatory diagrams sequentially showing a molding process according to another embodiment of the method of molding a boss portion of the present invention. In this embodiment, a step different from that of the embodiment shown in FIG. 5 is the same as that of the embodiment shown in FIG.
As shown in FIG. 6D, instead of the step of forming
The hemispherical portion 37b of the protruding portion 37 is perforated to form a through hole 3.
7c is formed. The perforation is performed by a known processing means in which a die and a punch are arranged vertically. At this time, since the hemispherical portion 37b is not extended at all,
The wall thickness of the wall does not decrease.

Finally, a well-known stretch flange process is performed on the protruding portion 37 having the through hole 37c, so that the through hole 3 is formed.
The diameter of the cylindrical portion 37a is reduced to a predetermined diameter while enlarging 7c to form the boss portion 41 having a desired shape as shown in FIG. At this time, the recess 38 becomes a ring-shaped recess 40 whose inner diameter is slightly reduced. Further, the method of forming the boss 41 of this embodiment is obtained by changing only a part of the steps of the embodiment of FIG. 5, and similarly to the embodiment, the formed boss 41 has The thickness of the plate 1 does not decrease over the entire cylindrical wall, and the height of the protrusion from the plate 1 also becomes an accurate predetermined value. In addition, by extending the protruding portion 37 in which the through hole 37c is formed in advance and performing flange processing,
Since the boss 41 can be formed at a time while enlarging the through hole 37c, the process can be simplified.

FIGS. 7A to 7E are process explanatory diagrams sequentially showing a molding process according to still another embodiment of the boss molding method of the present invention. (A) shows a flat plate-shaped workpiece 1 serving as a base material for forming a boss, and a central portion 1a of the plate 1 where a boss is to be formed is provided.
As shown in (b), the through-hole 42 is formed in advance by drilling. Next, the central portion 1a of the plate material 1 having the through-holes 42 is subjected to compression processing to form a spherical bulging portion 43 having a diameter considerably larger than the boss portion to be formed, as shown in FIG. Is molded. At this time, a ring-shaped concave portion 44 having a relatively small depth and a large inner and outer diameter is formed around the bulging portion 43. Since the bulging portion 43 is formed by a compressive stress that pushes up the central portion 1a of the plate 1 by the material flow force due to the compression processing, the bulge 43 has the same plate thickness as the plate 1 uniformly throughout.

Next, the bulging portion 43 is reduced in diameter by compressing the outer peripheral portion of the bulging portion 43 on the plate material 1 on which the bulging portion 43 is formed, as shown in FIG. A hemispherical portion 47b having a through hole 42 at the top of a cylindrical tubular portion 47a having a diameter slightly larger than the diameter of a desired boss portion to be formed.
Is formed to form a protruding portion 47 closed. At this time,
The material at the outer peripheral portion of the bulging portion 43 flows inward and acts to push up the bulging portion 43, thereby forming a protruding portion 47.
Wide ring-shaped recess 4 having an inner diameter smaller than 4
8 are formed. The protruding portion 47 having the through hole 42 in the hemispherical portion 47b not only does not cause a reduction in the thickness of the plate material 1 but also has a thickness at the base of the protruding portion 47 slightly larger than the thickness of the plate material 1. Have been.

Finally, the projecting portion 47 having the through hole 42 is stretched and flanged to reduce the cylindrical portion 47a to a predetermined diameter while expanding the through hole 42, as shown in FIG. Thus, the boss portion 49 having a desired shape is formed. At this time, the concave portion 48 becomes a wide ring-shaped concave portion 50 having a small inner diameter. The formed boss portion 49 does not cause a reduction in the thickness of the plate material 1 over the entire cylindrical wall,
The protruding height from the plate 1 also becomes an accurate predetermined value. Moreover,
As in the case of FIG. 6, the boss portion 49 can be formed at a stroke while expanding the through hole 42 by extending and flange-forming the projecting portion 47 in which the through hole 42 is formed in advance, so that the process can be simplified. Further, the through holes 4 are formed in the flat plate material 1 before processing.
By forming 2, the perforation process can be easily performed.

[0044]

As described above, according to the method for forming a hemispherical projection of the present invention, a predetermined portion of a plate material is pushed up by a material flow force when a recess is formed by performing a compression process. Since the material flow force is a compressive stress, the thickness of the formed hemispherical projection does not decrease with respect to the thickness of the plate material, and is the same as the thickness of the plate material as a whole. It has a uniform thickness.

Further, after a spherical bulge having a diameter larger than the diameter of the hemispherical protrusion to be formed is formed in advance by compression, the outer periphery of the bulge is further compressed to form a desired part. If the hemispherical protrusion is formed, the material can flow from a wide area of the plate material to a predetermined location, so that the concave portion formed around the hemispherical protrusion has a small depth. As a result, a decrease in strength can be suppressed. Further, since the material flow of the plate material is divided into two compression processes, there is an advantage that the hemispherical projection can be formed smoothly.

Further, if the step of compressing the bulging portion is repeated a plurality of times, a hemispherical projection having a large protruding height from the plate material and having the same plate thickness as the plate material over the whole is formed. In addition, since the material flow of the plate material is divided into a plurality of compression processes, the hemispherical projection can be formed more smoothly.

On the other hand, according to the method of forming the boss portion of the present invention, the concave portion was formed by performing compression working without using any tool such as a punch for pressing and forcibly spreading the plate material. A predetermined location of the plate material is pushed up by the material flow force at the time to first form a large-diameter spherical bulging portion, and then the diameter is repeatedly reduced to a predetermined diameter every time compression processing is performed at least twice. Since the inner portion is pushed up by the material flow force due to the processing to form the protruding portion and the headed cylinder portion sequentially, the material flow force is a compressive stress. Since the material can be pushed up without decreasing and the protruding height from the plate material can be sequentially increased, the formed boss portion has a plate thickness substantially equal to the plate thickness of the plate material over its entirety and a desired height in the cylinder center direction. Will have.

Further, if a flange is formed by extending a hemispherical portion having a through hole to a protruding portion in which the top of the cylindrical portion is closed, the boss portion can be formed at once while expanding the through hole. , The process can be simplified. In addition, if a through hole is formed in a flat plate material before processing, drilling can be easily performed.

[Brief description of the drawings]

FIG. 1 shows a processing step according to an embodiment of a method for forming a hemispherical projection according to the present invention, in which (a) is a longitudinal sectional view of a plate material before processing, and (b) is a longitudinal sectional view of a plate material after processing. FIG. 3C is a perspective view of the plate material after processing.

FIG. 2 is a longitudinal sectional view showing a compression processing step in the molding method.

3A and 3B are a longitudinal sectional view before and after a second compression process according to another embodiment of the method for forming a hemispherical projection of the present invention.

FIGS. 4A to 4D are process explanatory diagrams sequentially showing a molding process according to still another embodiment of the method for molding a hemispherical projection of the present invention.

FIGS. 5A to 5F are process explanatory diagrams sequentially showing a molding process of a method of molding a boss according to an embodiment of the present invention;

FIGS. 6A to 6E are process explanatory diagrams sequentially showing a molding process according to another embodiment of the method for molding a boss portion of the present invention.

FIGS. 7A to 7E are process explanatory diagrams sequentially showing a molding process according to still another embodiment of the boss molding method of the present invention.

FIG. 8 is a longitudinal sectional view showing a conventional hemispherical projection forming step.

FIG. 9 is a vertical cross-sectional view of a plate member partially formed with a hemispherical projection through the above molding step.

FIGS. 10A to 10E are process explanatory diagrams sequentially showing a molding process of a conventional boss portion molding method.

[Explanation of symbols]

1 plate material 9,20,24,28,30,32,34,38,4
0,44,48,50 recessed part 14,23,29,31 hemispherical projection 21,27,33,43 bulging part 31a, 37a, 47a cylindrical part 31b, 37b, 47b hemispherical part 37,47 projection 37c, 39c, 42 Through-hole 39 Headed cylinder 39a Tube 39b Top 41,49 Boss

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Mizuta 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. F term (reference) 4E087 AA02 AA10 BA19 EA11 EC11

Claims (5)

[Claims] An annular concave portion is formed at a predetermined position in a flat plate material, and compression processing is performed so that a material corresponding to the formation of the concave portion in the plate material flows to the inside of the concave portion. The method of forming a hemispherical projection, wherein the hemispherical projection is formed by pushing up an inner portion of the recess in the plate by the material flow force of the material. 2. An annular concave portion is formed at a predetermined position in a flat plate material, and compression processing is performed so that a material corresponding to the formation of the concave portion in the plate material flows to the inside of the concave portion. Thereby, the material flow force of the material pushes up the inner part of the recess in the plate material to form a spherical bulge having a diameter larger than the diameter of the hemispherical projection to be formed. Swelling portion forming step, and performing the same compression processing as the compression processing on the outer peripheral portion of the swelling portion to reduce the swelling portion to a predetermined diameter,
A hemispherical protrusion forming step of forming the hemispherical protrusion by deforming the bulging portion to be pushed up by a material flowing force inward of the material corresponding to the formation of the diameter reduction. A method for forming a hemispherical projection. 3. An annular concave portion is formed at a predetermined position in a flat plate material, and a compression process is performed so that a material corresponding to the formation of the concave portion in the plate material flows to the inside of the concave portion. Thereby, the material flow force of the material pushes up the inner part of the recess in the plate material to form a spherical bulge having a diameter larger than the diameter of the hemispherical projection to be formed. A bulging portion forming step, and performing the same compression processing as the compression processing on the outer peripheral portion of the bulging portion to reduce the diameter of the bulging portion, and an inner side of a material corresponding to the formation of the reduced diameter. A diameter reducing step of deforming the bulging portion so as to push it up by a material flowing force to the hemisphere, wherein the diameter reducing step is repeated a plurality of times, and the top of the cylindrical portion is closed with a hemispherical portion. Forming a hemispherical projection characterized by forming Shape method. 4. An annular recess is formed at a predetermined position in a flat plate material, and compression processing is performed so that a material corresponding to the formation of the recess in the plate material flows into the recess inside. By this, the material flowing force of the material pushes up the inner part of the recess in the plate material to form a bulged portion having a diameter larger than the diameter of the boss to be formed. Part forming step, performing the same compression processing as the compression processing on the outer peripheral part of the bulging part to reduce the diameter of the bulging part, and inwardly moving a material corresponding to the formation of the reduced diameter. A projecting portion forming step of forming the projecting portion in a shape in which the top of the tubular portion is closed by a hemispherical portion by deforming the bulging portion so as to be pushed up by a material flow force; and By performing the same compression processing as compression processing, The projecting portion is reduced in diameter to be deformed into a cylindrical portion having a predetermined diameter, and the hemispherical portion is compressed in the direction of the center of the cylinder to form a flattened top surface portion, and has a cylindrical portion and a top surface portion. A method of forming a boss portion, comprising: a headed cylinder portion forming step of forming a head cylinder portion; and a final step of forming a boss portion by performing a perforation process on the top surface portion. 5. An annular concave portion is formed at a predetermined position in a flat plate material, and compression processing is performed so that a material corresponding to the formation of the concave portion in the plate material flows to the inside of the concave portion. By this, the material flowing force of the material pushes up the inner part of the recess in the plate material to form a bulged portion having a diameter larger than the diameter of the boss to be formed. Part forming step, the same compression processing as in the compression step is performed on the outer peripheral part of the bulging part to reduce the diameter of the bulging part, and to the inward side of the material corresponding to the formation of the reduced diameter. A projecting portion forming step of deforming the projecting portion so as to be pushed up by the material flow force to form a projecting portion having a shape in which the top of the cylindrical portion is closed by a hemispherical portion; and a process prior to the projecting portion forming step Alternatively, in any of the post-processes of the projecting portion forming process, A perforation step of forming a through hole in a predetermined portion of the flat plate material before processing or any of the hemispherical portions of the protruding portion; and a flange extending to the protruding portion having a through hole in the hemispherical portion. A final step of forming the boss by enlarging the through-hole by performing processing.