JPH025490B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an overhanging method for forming a flanged cylindrical member by performing overhanging and burring on a plate-shaped material.

Conventional technology Conventionally, as a form of plastic working, a cylindrical member with a flange was manufactured by punching a hole in a part of a metal plate and forming a cylindrical part by extending the periphery of the hole. The burring process is known. For example, in the conventional burring process shown in FIGS. 11 to 13, a hole 40a with a diameter d ₁ =5 mm is drilled in a cold rolled mild steel plate (SPCC) 40 with a plate thickness t ₀ =2.3 mm, and then the periphery of this hole 40a is The part is burred under the conditions of (clearance between punch and die)/plate thickness ≧0.7 and plate thickness/inner diameter ≧0.15, and the tsuba 41
A cylindrical member 41 with a flange is manufactured in which a cylindrical portion 41b and a cylindrical portion 41b are integrally formed. In this conventional burring process, the cylinder height (burring height)
The limit is hmax/tube inner diameter dp≒0.2, and this ratio is
It was not possible to manufacture anything larger than 0.2.

In addition, in the overhang burring process shown in Figs. 14 to 17, the metal plate 42 as a material with a plate thickness t ₀ = 2.3 mm is processed in advance in the plate thickness direction at a processing speed v≒100 mm/sec.
Perform overhang processing to make inner diameter d ₃ = 12 mm, outer diameter d ₄ =
After forming an overhanging portion 43 of 14 mm and height h ₁ = 4.8 mm, a diameter
A hole 43b of 8.5 mm is drilled and the periphery of this hole is burred to manufacture a flanged cylindrical member 44 in which a cylindrical portion 44b is integrally formed on a flange 44a. In this overhang burring process, when the blank ratio, that is, the metal plate outer diameter D ₀ / the cylinder inner diameter dp = 2.5, the cylinder height (burring height) hmax / the cylinder inner diameter dp ≒ 0.4, and the metal plate outer diameter D ₀ / Cylinder inner diameter dp
If ≧5, burring height hmax/tube inner diameter dp
≒0.25 was considered to be almost the limit. That is,
If burring is performed with a value higher than this, cracks will appear in the cylindrical part.

Therefore, conventionally, when manufacturing a flanged cylindrical member 45 having a ratio exceeding the above-mentioned limit, as shown in FIG. It is manufactured by fixing one end of a metal cylindrical body 47 formed on the body by welding or the like.

Problems to be Solved by the Invention However, in the method of manufacturing a flanged cylinder member by welding, the accuracy becomes unstable due to thermal distortion when fixing the metal cylinder to the metal plate by welding. There were problems such as defects, which made it impossible to obtain sufficient attachment strength between the flange and the cylinder, and the welding work was complicated, leading to an increase in costs.

Therefore, in the conventional overhang burring processing method, when the overhang is first performed, the wall thickness of the overhang is thin, and when the burring is performed later, there is insufficient material to form the cylindrical portion. Focusing on the fact that a flanged cylindrical member with a ratio above the limit cannot be obtained, it has been found that by increasing the wall thickness of the overhanging portion, a flanged cylindrical member with a ratio above the above limit can be manufactured.

Therefore, an object of the present invention is to solve the above problems by reducing the height of the cylinder portion (burring height).
Items with a ratio of hmax/tube inner diameter dp that exceeds the above conventional ratio can be manufactured integrally without welding, eliminating the need for welding work, improving product accuracy, and connecting the collar and the tube. It is an object of the present invention to provide an overhang processing method which can obtain sufficient strength of a portion and further reduce costs.

Means for Solving the Problems In order to achieve the above object, the present invention first performs a preliminary overhang process on a material to form an overhang part, and then performs a second overhang process in the opposite direction to the overhang direction of the overhang part. After performing the overhang process, the overhang part formed by the second overhang process was subjected to burring. That is, a predetermined portion of the plate-shaped material is stretched to one side in the thickness direction to form a first overhang part, and then this first overhang part is stretched to the side opposite to the one side in the thickness direction. Next, a hole is formed in the bottom of the second overhang, and then the periphery of the hole is burred so that the hole enlarges in the opposite direction in the thickness direction. It was configured to form a cylindrical member with a flange.

Effect of the Invention In the above configuration, first, the material is stretched in the thickness direction to form a first overhang, and then the first overhang is stretched in the opposite direction to the above to form a second overhang. form, then
A hole is formed in the bottom of the second projecting portion, and then a cylindrical portion is formed by burring the periphery of the hole, thereby manufacturing a cylindrical member with a flange.

Examples Examples according to the present invention will be described in detail below with reference to FIGS. 1 to 10.

The overhang processing method according to this embodiment includes the first to
As shown in FIG. 5, in the first step, a predetermined portion of the metal plate 1 as a material is extended in one direction in the thickness direction to form a first overhang portion 2a, and then in the second step, the first overhang portion 2a is formed. 2a is extended in a direction opposite to the above-mentioned one direction to form a second overhang portion 3a, and then in a third step, this second overhang portion 3a is
A hole 3c is formed at the bottom of the hole 3c in the fourth step.
The cylindrical member 4 with a flange is formed by burring the periphery of the cylindrical portion 4a to form a cylindrical portion 4a.

In the first step, as shown in Figures 1 and 2,
A predetermined central portion of a circular metal plate 1 having a predetermined thickness t ₀ and a diameter D ₀ is bent in the thickness direction to form a first circular protrusion 2a having a substantially U-shaped cross section. At this time, the height of the first projecting portion 2a is defined as _h1 , and the inner diameter of the first projecting portion 2a is defined as _D1 . The range of the predetermined portion is determined so that a cylindrical portion 4a having a predetermined shape and a predetermined height _h4 can be formed in a subsequent step.

In the second step, as shown in FIG. 3, the first projecting portion 2a is curved in a direction opposite to the one direction, and a circular second projecting portion 3a has a substantially U-shaped cross section.
Perform overhang processing to form. The second at this time
Let the height of the overhanging part 3a be _h2 , the outer diameter of the second overhanging part 3a be _D2 , and the inner diameter be _D3 . The outer diameter D 2 of this second overhanging portion 3a is equal to the outer diameter D ₂ of the first overhanging portion 2.
The diameter is smaller than the outer diameter _D1 of a.

In the third step, as shown in FIG. 4, a hole 3c having a predetermined diameter _D4 is formed in the end surface of the bottom 3d of the second projecting portion 3a. The height of the second projecting portion 3a at this time is defined as _h3 . The hole 3c is necessary for burring in the fourth step. Further, the height _h3 is maintained to be approximately equal to the height _h2 .

In the fourth step, as shown in FIG. 5, the end surface of the second projecting portion 3a around the hole 3c is burred in the opposite direction to form the cylindrical portion 4a. The height of this cylindrical portion 4a is assumed to be _h4 .

Regarding the first and second steps described above, the processable areas for specific materials are shown below as an example.

That is, first, as an example, in the first step, using a cold-rolled mild steel plate (SPCC) with a plate thickness t ₀ = 2.3 mm, the processable area in the case of processing at a processing speed v≒100 mm/sec is calculated as As shown in the figure. Here, D ₀ is the outer diameter of the metal plate 1 as a material, D ₁ is the outer diameter of the first projecting portion 2a, and h ₁ max is the maximum height of the first projecting portion 2a. In Figure 6 above, the horizontal axis is D ₀ /
D ₁ , the vertical axis is h ₁ max/D ₁ , and in the region to the left of the straight line L ₁ in the figure, that is, D ₀ /D ₁ ≦approximately 1.7, the shape is deep drawn, that is, cup-shaped. Even if the parts in this area are overhanged in the first step, the second to fourth
This region is not possible because the cylindrical portion 4a of the predetermined height cannot be obtained when the process is reached. moreover,
In the area where D ₀ /D ₁ ≧ approximately 1.7, the curve slopes downward to the right.
In the region above _L2 , the thickness of the first overhanging portion 2a changes and breakage occurs, resulting in a defect in the first overhanging portion 2a, so this region is also prohibited. The above curve L ₂ is at each D ₀ /D ₁
This is a combination of h ₁ max/D ₁ determined experimentally and theoretically determined. Therefore, in the case of the above-mentioned steel plate, the region below the curve L ₂ and the region where D ₀ /D ₁ ≧about 1.7 is a region where overhang processing is possible.

Further, FIG. 7 shows the processable area when the first projecting portion 2a having a height h ₁ of 13 mm is processed to project in the opposite direction in the second step. The stretching conditions were a cold-rolled mild steel plate with a plate thickness t ₀ =2.3 mm and a processing speed v≈100 mm/sec. Here, D ₁ is the inner diameter of the first projecting portion 2a, D ₃ is the inner diameter of the second projecting portion 3a, and h ₂ max is the maximum height of the second projecting portion 3a. In the same figure, the vertical axis is h ₂ max/
D ₃ and the horizontal axis is D ₀ /D ₃ . In the figure, in the region above the straight line _L1 , the shape of the second projecting portion 3a is a deep drawn shape, that is, it consists only of the cylindrical portion 4a;
This region is unusable because it does not have a flange projecting from the base end of a. curve L ₃
That is, in the area below the curve indicating D ₁ /D ₃ =0 (that is, D ₁ =0 means that the second overhang 3a is not formed at all), the first overhang is formed in the first step. This is an area in which the method of this embodiment cannot be applied because the condition that the second projecting portion 3a is formed in the second step after forming the second projecting portion 2a is not met. Therefore, the above D ₁ /D ₃
It was investigated whether it was possible to form the first overhanging portion 2a in the first step by sequentially changing the value of . As a result, in the figure, when D ₁ /D ₃ = 2.0 and when D ₁ /D ₃ = 2.5, molding was possible in the region below the curve L ₁ , but the curve L ₂ (D ₁ /D ₃ =2.7), it was not possible to form a satisfactory second projecting portion 3a in the upper region. Therefore,
The region where the second step can be performed is below L ₁ and above L ₃ and where D ₁ /D ₃ =2.5 or less.

Next, processing equipment for carrying out the above-described stretching method is shown in FIGS. 8 to 10. Starting from FIG. 8, these are, in order, a first processing device 5 that performs the first step, a second processing device 6 that performs the second step, and a third processing device 7 that performs the fourth step.

The first processing device 5 is composed of an upper mold 8 and a lower mold 9, and a curved protrusion 9b is formed in the center of a mounting table 9a on the upper surface of the lower mold 9. On the other hand, at the lower part of the upper mold 8, a material support part 10 is fixed to the upper mold main body 11 at a central part corresponding to the central protrusion part 9b of the lower mold 9, and a support frame 11a is provided around the support part 10. A press punch 13 is suspended and supported on the main body 11. Therefore, after placing the plate-shaped material 1 cut out in advance to a predetermined size on the upper surface of the central protrusion 9b of the lower mold 9 as shown by the dotted line in the figure, the upper mold 8 is lowered to remove the material of the upper mold 8. The support part 10 contacts the central part of the material 1 and pinches the central part of the material 1 between the material support part 10 and the central projection 9b, and the pressing punch 13 presses the central part of the material 1. The periphery 1a of the material 1 is pressed downward to deform the periphery 1a of the material 1 so as to follow the shape of the protruding portion 9b, and an overhanging process is performed in which the first overhanging portion 2a protrudes upward. At this time, at the same time, a projection 9c formed in an annular shape on the mounting table 9a of the lower mold 9 bites into a predetermined location of the peripheral portion 2b of the first projecting portion 2a, and the annular positioning recess 2 is recessed upward.
form c. The positioning recess 2c also has the function of controlling the flow of material. When this processing is completed, the upper die 8 is raised and the eject pins 14, 14 of the lower die 9 are used to release the first projecting portion 2 from the lower die 9.
The first intermediate product 2 in which a is formed is discharged.

The second processing device 6 is composed of an upper mold 15 and a lower mold 16, and has a recess 16b formed in the center of a first intermediate product mounting table 16a on the upper surface of the lower mold 16, and a urethane rubber A spring 17 is provided. On the other hand, at the lower part of the upper mold 15, an overhang pressing punch 18 that enters the recess 16b of the lower mold 16 is fixed to the upper mold main body 19, and the punch 18 is fixed to the upper mold body 19.
The first protruding portion 2 of the first intermediate product 2 is placed around the first intermediate product 2.
A support portion 20 that contacts the peripheral portion 2b of the upper mold body 19 is suspended and supported. That is, this support part 2
0 is provided with an engaging protrusion 20a on its outer surface, and the engaging protrusion 20a is attached to the support frame 19 of the upper mold body 19.
The lower end position of the support part 20 is held so that it does not come off against the engagement protrusion 19b of a, and the lower surface of the support is positioned below the lower end of the press punch 18 at the lower end position of the support part 20. Therefore, the annular positioning recess 2c of the peripheral portion 2b of the first projecting portion 2a of the primary intermediate product 2 is fitted into the annular positioning protrusion 16c formed on the lower mold 16, and the first intermediate product The product 2 is positioned with respect to the mounting table 16a, and the first projecting portion 2
a is opposed to the recessed part 16b of the lower die 16, and the first projecting part 2a is arranged to project upward. Then, the support portion 20 comes into contact with the peripheral portion 2b of the first protruding portion 2a of the primary intermediate product 2, and the support portion 20
After sandwiching the peripheral portion 2b between the mounting table 16a and the mounting table 16a, the first protruding portion 2a is pressed with the pressing punch 18.
by pressing downward in the thickness direction of the first overhang portion 2
a into the recess 16b to form a second overhang 3a, and the second overhang 3a compresses the spring 17 within the recess 16b.
When the second projecting portion 3a is formed, the upper mold 15 is raised, and when the spring 17 returns to its original size due to elastic force, the second intermediate product 3 is moved to the lower mold 1.
The second intermediate product 3 is taken out from the lower mold 16 by pressing upward from the recess 16b of the second intermediate product 3. This taken out secondary intermediate product 3 is located at the bottom 3 of its second overhanging portion 3a.
After drilling a hole 3c in d using a drilling device (not shown), it is transported to the third processing device 7.

The third processing device 7 includes an upper mold 22 and a lower mold 3, and forms a recess 23b in the center of a mounting table 23a on the upper surface of the lower mold 23. On the other hand, in the lower part of the upper die 22, a press punch 24 for burring that fits into the recess 23b of the lower die 23 is fixed to the upper die body 25, and a curved part 24a which is curved in a tapered shape is attached to the tip of the press punch 24. A small diameter portion 24b is provided therebetween. Further, around the punch 24, a support part 26 that contacts the peripheral part 3b of the second projecting part 3a of the second intermediate product 3 is suspended and supported by the upper mold body 25. That is, this support part 26 is provided with an engagement protrusion 26a on its outer surface, and the engagement protrusion 26a is connected to the engagement protrusion 2 of the support part support frame 25a of the upper mold main body 25.
5b at the lower end position, and the lower end of the pressing punch 24 is positioned below the lower surface of the support at the lower end position of the support portion 26. Therefore, the second intermediate product 3 is placed on the lower mold 23 so that the second projecting portion 3a enters the recess 23b of the mounting table 23a of the lower mold 23, and the upper mold 22 is lowered. Then, the small diameter portion 24b of the pressing punch 24
is inserted into the hole 3c of the second overhang 3a of the second intermediate product 3, and the supporting part 26 of the upper die 22 is inserted into the peripheral part 3 of the second overhang 3a of the second intermediate product 3.
b, and the peripheral portion 3b is held between the support portion 26 and the mounting table 23a. In this state, while enlarging the hole 3c of the second intermediate product 3 using the curved portion 24a of the press punch 24, a burring process is performed to form a cylindrical portion 4a around the hole 3c within the recess 23b. As a result, the flanged cylindrical member 4 as a product is formed, and the upper mold 22 is raised to form the lower mold 23.
Take out the product 4 from the container.

Note that all of the above-mentioned 12, 21, and 27 are springs made of urethane rubber, and are wrinkle plate holders.

According to the above embodiment, the first projecting portion 2a is formed in the opposite direction to the direction in which the cylindrical portion 4a is formed, and the first projecting portion 2a is caused to project in the opposite direction to the above. A diameter D ₂ smaller than the diameter D ₁ of 2a,
By forming the second projecting portion 3a having a diameter D ₃ , the projecting height h ₃ of the second projecting portion 3a can be increased, and the height of the cylindrical portion 4a can be increased by burring. Therefore, even if the burring height is large, welding work is not required, the precision of the product is improved, and the strength of the connecting portion between the collar 4b and the cylindrical portion 4a is sufficient, so that costs can be reduced. Further, by forming the positioning recess 2c in the first intermediate product 2, when forming the second overhang 3a in the recess 2c in the second step, the first overhang 2a
Since the material is prevented from flowing along the mounting table 23a of the lower mold 23, the predetermined second projecting portion 3a can be reliably formed.

As an example, the method according to the above embodiment is applied to the plate thickness t ₀
= Maximum height of the cylindrical part when machining is performed using a 2.3 mm cold rolled mild steel plate (SPCC) at a processing speed v≒100 mm/sec
A product with hmax/tube inner diameter dp≒1.1 was manufactured.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented in various other embodiments. For example, the material is not limited to a circular one, but may be of any shape. Furthermore, the material is not limited to steel, but may be other materials. Further, the shapes of the first and second projecting portions 2a, 3a and the cylindrical portion 4a are not necessarily limited to circular shapes, but may be regular polygons with a large number of angles, such as a regular octagon or a regular decagon, and are close to a circle.

Effects of the Invention According to the above invention, the first projecting portion is formed in the direction opposite to the direction in which the cylindrical portion is formed, and the first projecting portion is made to project in the direction opposite to the above direction in which the cylindrical portion is formed. By forming the second overhanging part with a larger height, the overhanging height of the second overhanging part is increased, that is, a product in which the ratio of cylindrical part height (burring height) hmax/cylindrical part inner diameter dp is greater than or equal to the above-mentioned conventional ratio. can be manufactured reliably and integrally without welding the cylindrical part and the flange, eliminating the need for welding work. In other words, conventionally, overhang processing was performed once,
Compared to the overhang burring method in which the overhang formed by this process is subsequently subjected to burring, the first overhang is formed by performing the overhang in the opposite direction to the direction in which the cylindrical part is formed. The material in the part where the first overhanging part was formed becomes more likely to plastically flow, making it possible to increase the volume of the second overhanging part, making it easier to form the second overhanging part having a small outer diameter but a large height. The height of the part (burring height) can be increased, the precision of the product can be improved, and the connecting part between the collar and the cylinder part can have sufficient strength, which can reduce costs.

[Brief explanation of drawings]

1 to 5 are longitudinal sectional views of a raw material or an intermediate product in the processing steps of the overhang processing method according to an embodiment of the present invention, and FIGS. 6 and 7 are the implementation of the above method in the first step and second step, respectively. 8 to 10 are longitudinal cross-sectional views of the processing equipment in the first, second, and fourth steps, respectively. FIGS. 11 to 13 are process explanatory views of the conventional conventional burring method. 17 are process explanatory diagrams of a conventional method of performing burring after overhanging, and FIG. 18 is a longitudinal cross-sectional view of a conventional flanged cylindrical member. 1...Metal plate, 2...First intermediate product, 2a...
1st overhang, 2b...surrounding part, 3...2nd
Next intermediate product, 3a... Second overhang, 3b... Surrounding part, 3c... Hole, 3d... Bottom, 4... Product, 4a... Cylindrical part, 4b... Tsuba, 5, 6, 7... …
First, second, third processing devices, 8, 15, 22...
Upper mold, 9, 16, 23...Lower mold, 10, 20, 2
6... Support part, 11, 19, 25... Upper mold body,
12, 17, 21, 27... Spring, 13,
18, 24...Punch, 14...Eject pin.

Claims (1)

[Scope of Claims] 1. A predetermined portion of the plate-shaped material 1 is processed to extend to one side in the thickness direction to form a first projecting portion 2, and then, this first projecting portion 2 is formed to extend to one side in the thickness direction. The second overhanging portion 3 is formed by overhanging in the opposite direction, and then a hole 3c is formed in the bottom 3d of the second overhanging portion 3, and then the periphery of the hole 3c is formed in the opposite direction in the plate thickness direction. A bulging method characterized in that a flanged cylindrical member 4 is formed by burring so that the hole 3c is enlarged on the side. 2 The outer diameter of the second projecting portion 3a is smaller than the outer diameter of the first projecting portion 2a, and
2. The overhang processing method according to claim 1, wherein the overhang is performed so that the overhang height h ₂ of the overhang portion 3a is greater than the overhang height h ₁ of the first overhang portion 2a.