JPH084868B2 - Plastic forming method for members with holes - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic material for a perforated member which is capable of reducing a thinned portion generated on the outer circumference of an end portion when a perforated member having a through hole formed at the center thereof is obtained by plastic working. Regarding processing method.

[0002]

2. Description of the Related Art Conventionally, as a method of flattening both end faces of a member having the same cross section such as a cylinder, a prism, and a spur gear whose outer peripheral shape does not change in the axial direction, as shown in FIG. Things are known.

That is, in this method, the die 11 is
A die hole 15 having a shape corresponding to the member 13 having the same cross-section formed of the spur gear shown in FIG. 11 is formed. After charging, the material 17 is compression-molded by the punch 19 and the counter punch 21 that are fitted to one side and the other side of the die hole 15, and the material 1 is inserted into the die hole 15.
By filling 7 with the same cross-sectional shape member 13 as shown in FIG.

[0004]

However, in such a plastic working method for a member having the same cross-sectional shape, the punch 19 is used.
When the material 17 is compression-molded by the counter punch 21 and the counter punch 21, the material moves from the point closest to the material 17 to the point farthest from the material 17, that is, in the spur gear of FIG.
As the material is less likely to reach the tooth tip portion 25 as the tooth tip portion 25 is sequentially filled with the material from the tooth tip portion 25, as shown in FIG. There was a problem that the lacked portion 27 was generated.

If a high stress is applied to the raw material 17 in order to reduce the thickness lacking portion 27, the stress on the die 11 is increased and the die 11 may be damaged. Also,
In this method, the joining stress with the die 11 at the farthest point from the material 17 is extremely lower than the joining stress at the point closest to the material 17, and there is a partial variation in the spring back when the product is taken out. There is a problem that it is difficult to transfer the accuracy of the mold to the accuracy of the product.

The above-mentioned problem is that, as shown in FIG. 12, the mandrel 29 is inserted into the central portion of the material 17,
The same occurs when molding the hollow member 30 with holes. The present invention has solved the above-mentioned problems, and it is possible to significantly reduce the thickness reduction portion generated at the outer peripheral end of the perforated member as compared with the conventional one, and to improve the accuracy of the mold to the accuracy of the product. It is an object of the present invention to provide a plastic working method for a holed member that can be reliably transferred.

[0007]

A plastic working method for a holed member according to claim 1 is to insert a material into the die hole of a die in which a die hole having a shape corresponding to the holed member to be obtained is formed. In addition, after inserting the large diameter portion of the mandrel into the through hole formed in the center of the material, the material is compression-molded by a punch and a counter punch fitted to one side and the other side of the die hole, A roughing step of filling the material between the die hole and the large diameter part of the mandrel to obtain an intermediate material;
After this roughing process, the large diameter part of the mandrel is pulled out from the through hole of the intermediate material, the small diameter part of the mandrel is inserted into the through hole, and then the material is compression molded by the punch and counter punch. A finishing process for filling the material between the die hole and the small diameter portion of the mandrel.

According to a second aspect of the present invention, there is provided a plastic working method for a holed member, wherein a material is put into the die hole of a die in which a die hole having a shape corresponding to the holed member to be obtained is formed, and at the center of the material. In the through hole formed in, the large diameter portion and the step portion of the mandrel formed by connecting the large diameter portion and the small diameter portion by the step portion formed by the taper or the curved surface, in a state in which the mandrel is biased toward the small diameter portion side. After inserting, the material is compression-molded by punches and counter punches that are fitted to one side and the other side of the die hole to fill the material between the die hole and the large diameter part of the mandrel to form an intermediate material. After the roughing process to be obtained, and further after this roughing process, the material is compressed by the punch and counter punch, and the mandrel is moved against the biasing force by the material flow at this time, and the die hole and the mandrel are moved. Those having a finishing step of sequentially filling material between the small diameter portion.

[0009]

In the plastic working method for a holed member according to claim 1, in the finishing step, the material flows into the space formed between the intermediate material and the small diameter portion of the mandrel, and by this flow,
Flow of the material toward the outer peripheral edge of the intermediate material is promoted.

In the plastic working method of the holed member according to claim 2,
In the finishing process, compression of the material causes the material to flow to the stepped portion of the mandrel, and the material flow at this time moves the mandrel against the biasing force, causing the material to move between the die hole and the small diameter portion of the mandrel. Sequentially filled, this flow,
Flow of the material toward the outer peripheral edge of the intermediate material is promoted.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a plastic working apparatus used in an embodiment of the method for plastic working a holed member of the present invention, in which reference numeral 31 denotes a die.

The die 31 is formed with a die hole 35 having a shape corresponding to the holed member 33 made of a spur gear shown in FIG. A through hole 36 is formed in the holed member 33.

A punch 37 and a counter punch 39 are fitted on one side and the other side of the die hole 35 of the die 31, respectively. The counter punch 39 has through holes 4
1 is formed, and a knockout pin 43 is inserted in the lower portion of the through hole 41.

On the other hand, a small diameter portion 47 of the mandrel 45 is inserted in the upper portion of the through hole 41. Mandrel 45
Is composed of a small diameter portion 47 and a large diameter portion 49.
Is inserted into the punch 37.

The mandrel 45 is biased toward the knockout pin 43 side by the spring 51 arranged in the punch 37. An embodiment of the plastic working method for a holed member of the present invention is carried out by using such an apparatus as described below.

That is, in this embodiment, first, as shown in FIG. 1, the holed member 3 is placed in the die hole 35 of the die 31.
Material 5 having a through hole 53 smaller than the inscribed circle 3
5, the large diameter portion 49 of the mandrel 45 is positioned in the through hole 53.

After that, the punch 37 is lowered and the punch 3
The material 55 is compression-molded by 7 and the counter punch 39, and the material 55 is filled between the die hole 35 and the large diameter portion 49 of the mandrel 45 to obtain the intermediate material 57.

After that, as shown on the left side of FIG. 3, the knockout pin 43 is lifted to move from the through hole 59 of the intermediate material 57 to the large diameter portion 49 of the mandrel 45.
Is pulled out, and the small diameter portion 4 of the mandrel 45 is inserted into the through hole 59.
7 is located.

Thereafter, as shown on the right side of FIG. 3, the intermediate material 57 is moved by the punch 37 and the counter punch 39.
Is again compression-molded, and the material is filled between the die hole 35 and the small diameter portion 47 of the mandrel 45.

After the finishing step is completed, the punch 37 and the counter punch 39 are raised, and the holed member 33 formed into a predetermined shape is taken out. Therefore, in the above-described plastic working method of the holed member, the material 55 is put into the die hole 35 of the die 31 in which the die hole 35 having the shape corresponding to the holed member 33 to be obtained is formed. In addition, after inserting the large-diameter portion 49 of the mandrel 45 into the through hole 53 formed in the center of the material 55, the material 55 is punched by the punch 37 and the counter punch 39 fitted to one side and the other side of the die hole 35. Compression molding,
A roughing process for filling the material between the die hole 35 and the large diameter portion 49 of the mandrel 45 to obtain the intermediate material 57, and after this roughing process, from the through hole 59 of the intermediate material 57 to the large diameter portion of the mandrel 45. 49 is pulled out, the small diameter portion 47 of the mandrel 45 is inserted into the through hole 59, and thereafter, the material is compression-molded by the punch 37 and the counter punch 39 so that the die hole 35 and the small diameter portion 47 of the mandrel 45 are compressed. Since it is composed of the finishing process for filling the material, the thickness reduction portion generated at the outer peripheral end portion 61 of the holed member 33 can be made significantly smaller than the conventional one, and the precision of the mold can be made equal to the precision of the product. It is possible to reliably transfer.

That is, in this plastic working method for a holed member, in the finishing step, the material flows into the space formed between the intermediate material 57 and the small diameter portion 47 of the mandrel 45, and this flow causes the intermediate material to flow. Since the flow of the material toward the outer peripheral end portion 61 of 57 is promoted, it is possible to significantly reduce the thickness reduction portion generated in the outer peripheral end portion 61 of the holed member 33 as compared with the conventional case.

In the finishing process, the intermediate material 5
7 flows into the space formed between the small diameter portion 47 of the mandrel 45, the stress in the outer peripheral portion of the intermediate material 57 is dispersed and equalized, and the partial variation of the spring back when the product is taken out. Becomes smaller, and the accuracy of the mold can be reliably transferred to the accuracy of the product.

4 and 5 show another embodiment of the method of the present invention. In the plastic working apparatus used in this embodiment, the mandrel 63 is attached to the lower die 65 and the spring 67 moves upward. Mandrel 63 urged towards
A small-diameter portion 69 is formed on the upper part and a large-diameter portion 71 is formed on the lower part.

Then, a pin member 75 which is vertically movable is inserted into a through hole formed at the center of the punch 73. Further, a pin member 77 for moving the counter punch 39 is arranged outside the lower part of the mandrel 63.

In such an apparatus, as shown in FIG. 4, the rough machining process is performed with the large diameter portion 71 of the mandrel 63 inserted in the material 55, and thereafter, as shown in FIG. The mandrel 63 is moved downward by the pin member 75, and the finishing process is performed with the small diameter portion 69 of the mandrel 63 positioned in the through hole 59 of the intermediate material 57.

Also in the plastic working method of the holed member of this embodiment, it is possible to obtain substantially the same effect as that of the embodiment shown in FIG. 6 and 7 show still another embodiment of the method of the present invention, in which the plastic working apparatus used in this embodiment urges the die 31 above the die 31 toward the die 31 side. The upper die 81 is disposed, and the punch 85 is inserted into the through hole 83 of the upper die 81.

In such an apparatus, as shown in FIG. 6, the roughing process is performed by the upper die 81 and the punch 85, and then the finishing process is performed by the punch 85 as shown in FIG. Be seen.

Also in the plastic working method of the holed member of this embodiment, substantially the same effect as that of the embodiment shown in FIG. 1 can be obtained. 8 and 9 show still another embodiment of the method of the present invention. In the plastic working apparatus used in this embodiment, the large diameter portion 89 and the small diameter portion 91 of the mandrel 87 are tapered or curved. Are connected by a stepped portion 93.

In such an apparatus, as shown in FIG. 8, a through hole 97 having a relatively large clearance A with respect to the outer diameter of the large diameter portion 89 of the mandrel 87 is formed in the material 95. Material used is used.

Then, by lowering the punch 37, a roughing process and a finishing process are performed. That is,
In this embodiment, the forming step is performed with the holed member 3 to be obtained.
The material 95 is put into the die hole 35 of the die 31 in which the die hole 35 having the shape corresponding to 3 is formed.
The large diameter portion 89 and the step portion 93 of the mandrel 87 in which the large diameter portion 89 and the small diameter portion 91 are connected by the step portion 93 having a taper or a curved surface to the through hole 97 formed in the center of the
Is inserted with the mandrel 87 biased toward the small diameter portion 91 side, and then the material 95 is compression-molded by the punch 37 and the counter punch 39 fitted to one side and the other side of the die hole 35, and the die hole is formed. 35 and mandrel 87 large diameter section 8
9 and the roughing process for filling the intermediate material 57 with the raw material, and after this roughing process, the material is further compressed by the punch 37 and the counter punch 39, and the mandrel 87 is caused by the material flow at this time. Is performed against the urging force, and the finishing process step is performed in which the material is sequentially filled between the die hole 35 and the small diameter portion 91 of the mandrel 87.

In the finishing step, the intermediate material 57 is compressed to cause the material to flow to the stepped portion 93 of the mandrel 87, and the material flow at this time moves the mandrel 87 against the urging force to cause the die hole 35 to move. And the small diameter portion 91 of the mandrel 87 are sequentially filled with the material, and the flow of the material promotes the material to flow toward the outer peripheral end portion 61 of the intermediate material 57. It is possible to significantly reduce the thickness reduction portion generated at the outer peripheral end portion 61 of the holed member 33 as compared with the related art, and it is possible to reliably transfer the accuracy of the mold to the accuracy of the product.

In the above-mentioned embodiment, an example in which the method of the present invention is applied to the plastic working of the holed member 33 made of a spur gear has been described, but the present invention is not limited to this embodiment. The members with holes are cylinders, triangle poles, square poles,
Of course, it may be a hexagonal column or the like, or may be a helical gear, a bevel gear or the like.

[0033]

As described above, according to the plastic working method of the perforated member according to the first and second aspects, the undercut portion generated at the outer peripheral end portion of the perforated member is made much smaller than the conventional one. In addition, it is possible to reliably transfer the accuracy of the mold to the accuracy of the product.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a plastic working apparatus used in an embodiment of a method of plastic working a holed member of the present invention.

FIG. 2 is a front view showing a holed member formed by the apparatus of FIG.

FIG. 3 is an explanatory view showing a finishing process by the apparatus of FIG.

FIG. 4 is a cross-sectional view showing a plastic working apparatus used in another embodiment of the plastic working method for a holed member of the present invention.

5 is an explanatory view showing a finishing process by the apparatus of FIG.

FIG. 6 is a cross-sectional view showing a plastic working apparatus used in still another embodiment of the plastic working method for a holed member of the present invention.

FIG. 7 is an explanatory diagram showing a finishing process by the apparatus of FIG.

FIG. 8 is a cross-sectional view showing a plastic working apparatus used in still another embodiment of the plastic working method for a holed member of the present invention.

9 is an explanatory diagram showing a finishing process by the apparatus of FIG.

FIG. 10 is an explanatory diagram showing a conventional plastic working method for a member having the same cross-sectional shape.

FIG. 11 is a front view showing a member having the same cross section formed by the method of FIG.

FIG. 12 is an explanatory view showing another example of the conventional plastic working method for a member with holes.

[Explanation of symbols]

31 die 33 member with hole 35 die hole 37 punch 39 counter punch 45 mandrel 47 small diameter part 49 large diameter part 55 material 57 intermediate material

Claims (2)

[Claims] 1. A raw material is put into the die hole of a die having a die hole having a shape corresponding to a holed member to be obtained, and a large diameter mandrel is formed in a through hole formed in the center of the raw material. After inserting the part, the material is compression-molded by a punch and a counter punch that are fitted to one side and the other side of the die hole to fill the material between the die hole and the large diameter part of the mandrel. A roughing process to obtain an intermediate material,
After this roughing process, the large diameter part of the mandrel is pulled out from the through hole of the intermediate material, the small diameter part of the mandrel is inserted into the through hole, and then the material is compression molded by the punch and counter punch. And a finishing step of filling a material between the die hole and the small diameter portion of the mandrel. 2. A material having a large diameter is formed in a through hole formed in the center of the material while the material is put into the die hole of a die having a die hole having a shape corresponding to the holed member to be obtained. And the small-diameter portion, the large-diameter portion and the step portion of the mandrel connected by a step portion formed of a taper or a curved surface, after inserting the mandrel with the mandrel being biased toward the small-diameter portion, one side of the die hole and A roughing process of compressing and molding the material by a punch and a counter punch fitted to the other side to fill the material between the die hole and the large diameter part of the mandrel to obtain an intermediate material, and the roughing process After that, the material is compressed by the punch and counter punch, and the material flows between the die hole and the small-diameter portion of the mandrel while sequentially moving the mandrel against the urging force. Let A plastic working method for a member having a hole, comprising: a finishing step.