JP3518004B2 - End face cutting method for annular workpiece and end face forming die used for the end face cutting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end face cutting method for cutting an unnecessary flange-shaped end portion in a processed product having an annular opening end portion having a flange shape, and for end face forming used in the end face cutting method. Regarding molds.

[0002]

2. Description of the Related Art For example, a cylindrical part such as a motor case is
It is obtained by forming a flat plate material into a cylindrical shape by pressing (drawing), and then cutting the flange portion formed at the peripheral edge of the opening of the formed work. Cut the flange part
As a removing method, there is a cutting method disclosed in Japanese Patent Application Laid-Open No. 3-210920. This cutting method will be briefly described with reference to FIGS. The work 100 formed in the previous step (see FIG. 6) is placed on the stepped punch 200, and drawn and squeezed by the annular die 300 (see FIG. 7). Here, the die 300 has the same radius dimension at the tip inner peripheral portion as the die 310 used in the previous step, but the inner diameter is set to be smaller by the seam allowance. By this drawing, the flange portion 110 of the work 100 is
A thin constricted portion 120 is formed on the surface (stepping step).

Subsequently, the work 100 having the constricted portion 120 is put on a cutting punch 400 (having the same shape as the stepped punch 200), and the die 500 having an acute inner peripheral edge is lowered. As a result, a crack is generated in the narrowed portion 120, the crack progresses, and the narrowed portion 120 is cut (see FIG. 8). According to this cutting method, the work 100
Since the cylindrical portion is squeezed so as to have a set dimension and then cut, it is possible to provide a processed product having good dimensional accuracy and high roundness. Further, since the generation of burrs is prevented, deburring (cutting step) after cutting is unnecessary.

[0004]

In the above-mentioned cutting method, the step forming step is performed by drawing and squeezing. Therefore,
The surplus meat that is discharged as the die 300 descends flows to the corners 200a of the stepped punch 200, and the corners 200a are filled with the flowing material, so that the cut end face can be projected at a right angle and the flatness can be improved. Is obtained.

However, since the stepped punch 200 used in the stepping step has an integral structure, when the side wall of the work 100 receives the mark and flows to the corner portion 200a of the stepped punch 200, the stepped punch 200 is pressed. Air or oil collects in the corners 200a and prevents the material from flowing. Therefore, as shown in FIG. 9, when the stepping process is completed, the work 100
The sag 130 remains on the inner peripheral edge of the above, and a sufficient flat surface cannot be obtained. In addition, in the conventional cutting method, since ironing is indispensable, a material thicker than the plate thickness of the finished product is required. Therefore, there is also a problem that the material cost is increased and the unit price of the product is increased.

Further, the plate thickness of the material is constantly changing,
For example, when the plate thickness is thin, the seam allowance is reduced in the stepping process, so that the amount of the sag 130 increases and the plane of the opening end (cut end face) also decreases. In addition, the flat surface is similarly reduced even when the hardness or elongation of the material changes. However, with respect to this variation in plate thickness (especially when the plate thickness is thin), a die with a small inner diameter is used to take a large amount of seam allowance. At this time, methods such as compressing the entire length of the work together with the ironing process can be considered.

However, the method (1) is not suitable for mass production because the cost of the die to be replaced and the number of man-hours required to replace the die are large, resulting in a significant increase in cost. on the other hand,
The method of can be handled with a slight change in the die (thus,
(The cost increase due to the change of the mold is small), but when the stepped punch 200 is covered with the work 100 having an increased overall length,
As shown in FIG. 10, the flange portion 110 of the work 100
The inner peripheral surface rides on (steps in contact with) the stepped corner portion 200b of the stepped punch 200, and the bottom surface 100a of the work 100 does not adhere to the upper end surface 200c of the stepped punch 200. When the ironing process is performed in this state, as shown in FIG. 11, the inner wall portion 100b connected to the bottom surface 100a of the work 100 is deformed inward and becomes a defective product.

The present invention has been made based on the above circumstances. A first object of the present invention is to reduce the influence of fluctuations in materials.
A second object is to provide an end face forming die suitable for mass production, and a second object is to provide an end face cutting method for an annular processed product capable of suppressing sagging and increasing the flatness of the end face. .

[0009]

In order to achieve the first object, the present invention employs the following constitution in claim 1. For a processed product in which the opening end portion is expanded to the outer periphery with respect to the side wall portion provided in an annular shape, a step portion is provided between the side wall portion and the flange-shaped end portion to reduce the wall thickness. An end face forming die for performing a step forming step for forming a constricted portion, a lower die for holding the processed product from the inside of the processed product, and a drawing compression process from the outside of the processed product. The lower die comprises an inner punch for supporting the inner peripheral surface of the processed product, and the inner punch.
Disposed inside, along the outer peripheral surface of the inner punch consists of an outer punch having a cylindrical portion forming an end face of the annular pre
The inner punch and the outer punch are relatively movable while the inner punch is in sliding contact with the inner surface of the cylindrical portion, and the upper die is operated along the outer peripheral surface of the side wall portion, and the outer punch and From an annular drawing die for giving a drawing to the processed product between, and a compression member that is arranged inside the drawing die and compresses the side wall portion in the height direction with respect to the end surface of the outer punch. It is characterized in that the diaphragm die and the compression member are movable relative to each other.

Further, in order to achieve the second object, the following constitution is adopted in claim 2. For a processed product in which the opening end portion is expanded to the outer periphery with respect to the side wall portion provided in an annular shape, a step portion is provided between the side wall portion and the flange-shaped end portion to reduce the wall thickness. It is an end face cutting method which performs the cutting process which cuts and removes the said flange-shaped end part by the said constricted part, after performing the step | step formation process which forms a constricted part, The end surface shaping metal mold of Claim 1 In the stepping step performed by using the stepped product, the processed product is set in the lower mold with the side wall portion fitted to the inner punch .
After that, by lowering the upper die, the inner punch is moved.
While being pushed down while slidingly contacting the inner surface of the tubular portion ,
While compressing the side wall portion with respect to the end surface of the outer punch by the compression member, by lowering the drawing die along the outer peripheral surface of the side wall portion to apply drawing,
The end face of the outer punch bites between the side wall portion and the flange-shaped end portion of the processed product to form the constricted portion and the step portion.

[0011]

According to the present invention described in claim 1, the lower die is not an integral structure, and the inner punch is the outer pan.
In this structure, the inner punch and the outer punch are relatively movable while slidingly contacting the inner surface of the cylindrical portion of the chi . Therefore, in the step process, the compression process can be performed along the entire length of the processed product, that is, the height direction of the side wall. Therefore, the step portion can be provided by compressing the side wall portion with respect to the end surface of the outer punch without performing the side wall portion stamping as in the conventional case. As a result, in the end face molding die of the present invention, it is not necessary to perform squeezing on the processed product, so that the influence of the variation of the material (in particular, variation of the plate thickness) is reduced. That is, since it is not necessary to replace the die (upper die) due to the variation of the material, it can be said that it is suitable for mass production.

According to a second aspect of the present invention, after performing a stepping step using the end face molding die according to the first aspect, the constricted portion formed in the stepping step forms a flange-shaped end. Cut and remove parts. In the stepping process, the end face of the outer punch ( the end face of the tubular portion) bites between the side wall part and the flange-shaped end part of the processed product by the drawing process using the drawing die and the compression process using the compression member. A narrowed portion is formed. In addition, the material of the processed product flows along the end face of the outer punch to the corner of the end face of the outer punch (the corner formed by the outer peripheral face of the inner punch and the end face of the tube ) along with the formation of the constricted portion. Provides a stepped portion.

At this time, air and oil are spilled along with the flow of material.
Although it is pushed into the corner of the end face of the part , because the inner punch and the outer punch that make up the lower die move relative to each other, air or oil slides between the inner punch and the outer punch. Can be discharged through the gap. Therefore, the material flows smoothly, and the end surface of the outer punch (the cylindrical portion
The material is surely flowed to the corners of the end surface) , so that sagging is suppressed and a highly accurate flat surface is obtained. Also,
According to the present invention, the opening end face can be formed by the squeeze compression process, not by the squeeze process. Therefore, unlike the conventional case, it is not necessary to consider the margin of the thickness of the material, and it is possible to process from a material thickness equivalent to the finished product,
Therefore, the material cost can be reduced.

[0014]

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 to 3 are cross-sectional views showing the steps of the step forming process. In this embodiment, an unnecessary flange portion 1a is cut and removed from a cylindrical product 1 (hereinafter, referred to as a work 1) having a flange portion 1a at an opening end portion.
3) and a cutting step (see FIG. 4). The work 1 (annular processed product of the present invention) is obtained by drawing a plate material 1 ′ (see FIG. 5 (a)), and has a bottomed cylindrical portion 1 b (side wall portion of the present invention) and the cylindrical portion 1 b. And a flange portion 1a (flange-shaped end portion of the present invention) extending from the opening peripheral edge to the outer periphery (see FIG. 5).

In the step forming step, the step portion 1c and the constricted portion 1d are provided between the cylindrical portion 1b of the work 1 and the flange portion 1a (see FIG. 5).
(Refer to FIG. 4), and is performed using an end face molding die described below. The end face forming die includes a lower die A and an upper die B. The lower die A includes a mold base 2, an end face forming punch 3 fixed to the mold base 2 (outer side punch of the present invention), and a spigot punch 4 arranged inside the end face forming punch 3 (of the present invention). Inner punch). The end face forming punch 3 is provided in a stepped cylindrical shape composed of a small diameter cylindrical portion 3a and a large diameter cylindrical portion 3b, and has a cylindrical shape according to the present invention.
The outer diameter of the small diameter cylindrical portion 3a forming the portion is provided to be substantially equal to the outer diameter of the cylindrical portion 1b of the work 1.

The spigot punch 4 is pre-processed (drawing process).
Is provided in the same shape (approximately the same outer diameter) as the punch (not shown) used when forming the cylindrical portion 1b. The spigot punch 4 is arranged so as to be movable in the vertical direction with respect to the end face forming punch 3 (slidingly in contact with the inner peripheral surface of the small-diameter cylindrical portion 3 a), and is moved upward by a spring 5 arranged between it and the mold table 2. Is urged to. However, the protruding portion 4 a provided on the outer periphery of the lower end portion of the inlay punch 4 is not
The upward movement is restricted by being locked to the step surface 3c between the large-diameter cylindrical portion 3b and the small-diameter cylindrical portion 3a. The height of the inlay punch 4 protruding upward from the upper end surface 3d of the end face forming punch 3 is such that when the work 1 is set on the inlay punch 4 (the state shown in FIG. 1), the flange portion 1a of the work 1 has an end face. The height is set so as not to interfere with the forming punch 3.

The upper die B comprises a die stand 6, a die 7 fixed to the die stand 6 for drawing, and a knockout plate 8 arranged inside the die 7 (compressing member of the present invention). Composed of and. The die 7 is provided in a cylindrical shape having a radius inside the opening, and the inner diameter of the die 7 is the cylindrical portion 1 of the work 1.
The diameter is equal to or slightly larger than the outer diameter of b. The knockout plate 8 is slidably in contact with the inner peripheral surface of the die 7 so as to be movable in the vertical direction, and is urged downward by a spring 9 arranged between the knockout plate 8 and the die table 6.

The cutting step is for cutting and removing the flange portion 1a at the constricted portion 1d of the work 1 formed in the stepping step, and is performed using a cutting die described below. The cutting die is composed of a lower die C and an upper die D, as shown in FIG. The lower mold C includes a mold base 10 and a cutting punch 11 fixed to the mold base 10. The cutting punch 11 includes a small diameter portion 11a and a large diameter portion 11b.
And the outer diameter of the small diameter portion 11a is substantially equal to the outer diameter of the inlay punch 4 and the large diameter portion 11b.
Is set to be slightly smaller than the inner diameter of the constricted portion 1d of the work 1.

The upper mold D comprises a mold base 12, a cutting die 13 fixed to the mold base 12, and a knockout plate 14 disposed inside the die 13.
The die 13 is provided in a cylindrical shape with an acute angle inside the opening,
The inner diameter is set to be slightly larger than the outer diameter of the cylindrical portion 1b of the work 1 and the outer diameter of the large diameter portion 11b of the cutting punch 11. The knockout plate 14 is slidably in contact with the inner peripheral surface of the die 13 so as to be movable in the vertical direction, and is urged downward by a spring 15 arranged between the knockout plate 14 and the die base 12.

Next, the operation of this embodiment will be described. (A) Stepping process The inlay punch 4 is covered with the work 1 formed in the preceding process. At this time, no gap is formed between the bottom surface 1e (inside) of the work 1 and the upper end surface 4b of the inlay punch 4, and the work 1 is set in a close contact state.

Then, the upper die B is lowered. With the lowering of the upper die B, first, the knockout plate 8 hits the bottom surface 1f (outer side) of the work 1 and the inlay punch 4 and the knockout plate 8 urged by the respective springs 5 and 9 The bottom surface 1e of the work 1,
1f is held in close contact. As the die 7 descends together with the mold table 6 in this state, the work 1 (cylindrical portion 1b) enters the opening of the die 7 as shown in FIG. In other words, the die 7 descends along the outer peripheral surface of the cylindrical portion 1b.

After the die 7 further descends and the radius R of the tip of the die 7 reaches the flange portion 1a of the work 1, the inlay punch 4 is pushed down together with the work 1 as the die 7 descends. 1 flange part 1a
Contacts the outer peripheral edge of the end face forming punch 3 (see FIG. 2). Then, the radius R of the tip 7 of the die 7 reduces the wall thickness of the work 1 so that the corners of the end face forming punch 3 bite between the cylindrical portion 1b of the work 1 and the flange portion 1a. At the same time, the knockout plate 8 descends while compressing the cylindrical portion 1b of the work 1 with respect to the upper end surface 3d of the end face forming punch 3, so that the material of the work 1 is moved along the upper end face 3d of the end face forming punch 3 to the upper end surface 3d. It flows to the corner of 3d (the corner formed by the outer peripheral surface of the inlay punch 4 and the upper end surface 3d of the end face forming punch 3). Then, the drawing / compressing process is completed in a state where the inlay punch 4 is in close contact with the mold base 2 and the knockout plate 8 is in close contact with the mold base 6.
Between the cylindrical portion 1b of the work 1 and the flange portion 1a, as shown in FIGS. 3 and 5 (c), a step portion 1c and a constricted portion 1d are formed.

(B) Cutting step The work 1 having the stepped portion 1c and the constricted portion 1d is placed on the cutting punch 11 (at this time, the stepped portion 1c of the work 1 formed in the step forming step is the cutting punch 11). Step surface 1
1c), the upper die D is lowered.
As a result, the cutting die 13 moves the work 1 (cylindrical portion 1
b) descending along the outer peripheral surface, the sharp inner edge of the opening cuts the constricted portion 1d of the work 1, and the flange portion 1a is separated from the cylindrical portion 1b as shown in FIG. The work 1 from which the flange portion 1a has been separated has no sagging inside the opening end, and a highly accurate flat surface can be obtained (FIG. 5).
(See (d)).

(Effect of Embodiment) According to this embodiment, the lower die structure of the end face forming die has a separate structure in which the end face forming punch 3 and the inlay punch 4 are relatively movable. Air and oil pushed by the flow of the material during the squeezing and compressing process can be discharged from the gap between the end face forming punch 3 and the inlay punch 4. As a result, the material surely flows to the corners of the upper end surface 3d of the end face forming punch 3, the occurrence of sagging is suppressed, and the squareness of the opening end face of the work 1 is obtained. It is possible to form an end surface having high circularity and high flatness.

Further, in this embodiment, during the step of forming,
The end face of the work 1 is formed by performing drawing compression processing. That is, since it is not necessary to perform the drawing and squeezing as in the conventional case, the influence of the variation of the material (in particular, the variation of the plate thickness) is reduced. Therefore, it is not necessary to replace the die (upper die B) due to the change of the material, and the cost can be reduced accordingly. As a result, it is possible to provide a highly accurate work 1 that can be mass-produced stably for a long period of time.

Further, in this embodiment, since the ironing is not performed, it is not necessary to consider the ironing margin in the thickness of the raw material as in the conventional case, and the raw material corresponding to the finished product can be processed. That is, since the plate thickness of the material can be used as it is as the plate thickness of the finished product, the material cost can be reduced accordingly. Further, since the ironing process is not performed, seizure of the inner diameter portion of the die 7 for drawing can be suppressed, and it becomes possible to reduce defective products for seizure and extend the die life of the die 7.

[Modification] Although the cylindrical work 1 is used in the present embodiment, an annular body other than the cylindrical shape, for example, a polygonal shape may be used. Further, as the processing in the previous step, a processing method other than the drawing processing, for example, overhanging processing, burring processing, etc. may be used. Therefore, the work 1 processed in the previous step does not necessarily have to have a bottomed shape. This embodiment is based on the fact that the ironing process is not performed, but for example, there is a restriction on the product shape (when it is desired to make the side wall portion thinner than the bottom wall thickness), or the work material having poor fluidity during the stepped portion processing. As a further measure for suppressing sagging in the case of adopting, it is possible to add squeeze processing during the stepping process.

The end face molding die has a structure in which both the spigot punch 4 and the knockout plate 8 are biased by springs 5 and 9, but biasing means other than the springs 5 and 9, such as an air cushion, may be used. good. Further, the end face forming punch 3 may have a structure which can be moved due to the shape of the product or the progressive type structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a stepping process.

FIG. 2 is a cross-sectional view showing a step forming process.

FIG. 3 is a cross-sectional view showing a step process.

FIG. 4 is a cross-sectional view showing a cutting process.

FIG. 5 is a cross-sectional view showing a change in shape associated with a working process of a work.

FIG. 6 is a cross-sectional view showing a previous process.

FIG. 7 is a cross-sectional view showing a stepping process (prior art).

FIG. 8 is a cross-sectional view showing a cutting process (prior art).

FIG. 9 is a cross-sectional view of a work in which sagging has occurred (prior art).

FIG. 10 is a cross-sectional view showing a state in which a conventional stepped punch is covered with a work having a long overall length.

FIG. 11 is a cross-sectional view in the case where drawing and squeezing is performed from the state shown in FIG.

[Explanation of symbols]

1 Work (Processed Product) 1a Flange (Flanged End) 1b Cylindrical (Sidewall) 1c Step 1d Constriction 3 End Face Forming Punch (Outer Punch) 3a Small Diameter Cylinder (Cylinder) 3d End Face Forming Punch the upper end surface (end surface on the small-diameter cylindrical portion) 4 Pilot punch (inner punch) 7 diaphragm die 8 knockout plate (compression member) a lower mold (the end face mold) B upper mold (the end face mold )

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-210920 (JP, A) JP-A-5-228563 (JP, A) Actually opened 62-96938 (JP, U) Actually opened 60- 146526 (JP, U) S. 45-21728 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21D 24/16

Claims (2)

(57) [Claims] 1. A stepped portion is provided between the side wall portion and the flange-shaped end portion for a workpiece in which an opening end portion of the annular side wall portion is formed in a flange shape in which the end portion expands to the outer periphery. A die for end face forming for performing a step forming step for forming a thin constricted portion, including a lower die for holding the processed product from the inside of the processed product, and a drawing from the outside of the processed product. The lower mold comprises an inner die for supporting the inner peripheral surface of the processed product, and the inner punch is arranged inside, and the inner die is annular along the outer peripheral surface of the inner punch. An outer punch having a tubular portion forming an end surface of the inner punch , the inner punch being an inner surface of the tubular portion.
The inner punch and the outer punch are relatively movable while slidingly contacting with each other, the upper die is operated along the outer peripheral surface of the side wall portion, and the workpiece is drawn between the outer punch and the outer punch. die throttle ring to give, and arranged inside this aperture die consists compression member for compressing the side wall portion in the height direction relative to the end face of the outer punch, the compression and the diaphragm die An end face molding die, characterized in that it is movable relative to the member. 2. A stepped portion is provided between the side wall portion and the flange-shaped end portion for a processed product in which an opening end portion of the annular side wall portion has an opening end portion expanding to the outer periphery. After performing the step process to form a thin constriction with
It is an end face cutting method which performs a cutting process of cutting / removing the flange-shaped end portion by the constricted portion, wherein the step forming process performed by using the end face forming die according to claim 1 is performed on the inner punch. After installing the processed product in the lower mold with the side wall fitted together, lower the upper mold.
By doing so, the inner punch is brought into sliding contact with the inner surface of the tubular portion.
While being pressed down while compressing the side wall portion with respect to the end surface of the outer punch by the compression member, the drawing die is lowered along the outer peripheral surface of the side wall portion to apply drawing, An end face of an annular processed product, characterized in that the end face of the outer punch bites between the side wall part and the flange-shaped end part of the processed product to form the constricted part and the stepped part. Cutting method.