JPH0561009B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for forming a forged product, and in particular, to a method for forming a forged product, in particular, a blank obtained from a lubricated plate material is molded with the lubricated surface of the blank into a forged workpiece. The present invention relates to a forming method in which a forged product is formed by forging while being used as a sliding surface with a die.

[Background technology and its problems]

The shape of the punched blank (material) is determined based on the shape of the product to be processed, production efficiency, etc. Therefore,
Blanks are often punched out of coil material or flat plate material (hereinafter collectively referred to as plate material).

Generally, in the case of cold forging, the blank slides against the forging die with extremely high contact pressure, so the quality of lubrication determines the success or failure of the process. If the lubrication of the blank is not good, seizure or galling will occur between the blank and the forging die, causing local breakage and rapid friction of the forging die, and shortening the life of the forging die. Significantly decreased. Furthermore, there may be cases where processing itself is impossible.

Further, the load required for forming is the sum of the deformation strength inherent to the material and the frictional resistance between the forging die and the blank. Therefore, the better the lubrication of the blank, the higher the degree of machining.

However, in highly processed work, if liquid lubrication such as mineral oil is used, the lubrication strength is insufficient, and the blank and the forging die come into direct contact.
Fall from lack of lubrication. For this reason, we actively add a solid layer that retains the lubricant on the surface of the blank, that is, a lubrication retaining layer formed from a zinc phosphate coating, which is a typical example because it is easy to process and has a small coefficient of friction. A lubricant is applied to the lubricant retaining layer for lubrication.

The conventional method for forming blanks was to punch them out from a plate using a press. As shown in FIG. 13, the punching method is to punch out the blank 10 from the plate material 1 at once using a punch die 4 and a punch 3 with dimensions D ₁ <D ₂ . Therefore, on the outer circumferential surface 11 of the blank 10, as shown in FIG. 14, there is a sheared surface S that has undergone large shear strain, and a crystal grain surface appears at the cracked and fractured portion, resulting in a fractured surface with significant minute irregularities. B has occurred. These surfaces are collectively referred to as a new surface N, and even if the plate material 1 is lubricated, this surface may run out of lubrication. For this, blank 1
0 as shown in FIG. 15A, the forging die 20
If the forging punch 300 is attached to the forging die 400 of No. 0 and processed by the backward extrusion method as shown in FIG.
It directly contacts the inner wall surface 401 of 00 and cannot be processed well. Therefore, conventionally, punched blanks of 10
The oil was re-lubricated.

However, according to the conventional method of forming the blank 10, an excessive amount of labor and money is required for re-lubrication treatment, resulting in poor production efficiency. This means, for example, that blank 1 is added to Bonderite (trade name) aqueous solution.
When immersing 0, degreasing before and after, washing with water,
When considering pickling, neutralization, etc., its shortcomings can be easily understood even if only the formation of the lubrication-retaining layer is considered. In this way, even if the plate material 1 was lubricated, it was not effectively utilized as the blank 10. Furthermore, this also has the problem that the forming and cold forging processes from the plate material 1 to the blank 10 cannot be performed consistently, and as a result, automation and labor saving are hindered.

[Purpose of the invention]

An object of the present invention is to provide an excellent method for forming forged products that eliminates the above-mentioned problems and can dramatically improve production efficiency and economic efficiency by enabling integrated work from blank forming to forging processing. With the goal.

[Means and actions for solving problems]

(Means) Since the conventional method for forming a punched blank is to punch out a plate material at once, the present invention has the following advantages:
Focusing on the disadvantage and inconvenience of having to carry out re-lubrication treatment, the present invention is characterized in that it is possible to effectively utilize the lubricated surface that has already been applied to the plate material.

Therefore, there is a method of forging a blank obtained by punching a lubricated plate material to form a forged product, in which the lubricated back side of the plate material is directed toward the preforming die side. After performing preforming by pushing a preforming punch from the front side to form an upright surface on the back side that maintains the lubrication treatment, the upright surface formed by the preforming is inserted into the preforming die. The blank is accommodated in a hole of a punching die having a size larger than the blank size, and then a punch is pushed in from the front side to punch a blank from the plate material, and then,
The blank is housed in a forging die and forged with a forging punch, thereby:
This aims to achieve the above objective.

(Function) Since the present invention has the above-described configuration, first, the back side of the lubricated plate material is set in the preforming die, and the preforming punch is pushed in from the front side to form the upright surface on the back side. Perform preforming. As a result, the upright surface is an extension of the lubricated surface on the back side, and this lubricant is also extended in the same way.
The effect lasts. Further, a constricted portion is formed on the plate material in order to form a new surface having a dimension smaller than the thickness of the plate material.

Next, the preformed plate material is set so that its upright surface is accommodated in the hole of the punching die, and a punch is pushed in from the surface side to form a punching blank.

As a result, the outer peripheral surface of the molded blank is formed from the upright surface. Therefore, the blank can be treated as having a lubricated surface on the entire surface except for a part of the new surface. That is, the lubricated surface of the plate material can be effectively used as a sliding surface that comes into contact with the inner wall surface of the die for forging the blank.

Here, the erected surface refers to a plane formed to have a certain angle with respect to the original plane of the plate material.

〔Example〕

Embodiments of the method for forming a forged product according to the present invention will be described in detail with reference to the drawings.

(First Embodiment) The first embodiment is shown in FIGS. 1 to 5, in which a plate material 1 is continuously transferred to a preforming die 20 and a punching die 2, a blanking process is performed, and then a blanking process is performed. This is a case where cold forging is performed using the forging die 200. The blanking process includes a preforming process and a punching process. The preforming process is performed by a boss forming method using a preforming punch 30 and a preforming die 40 that form a preforming mold 20, and the details will be explained mainly with reference to FIG. do. The preforming punch 30 is provided with a cutting edge portion 32 having a size equal to or larger than the pushing amount t from the banking plate 31, and the diameter of the cutting edge portion 32 is D _{10 .}
It is said that The diameter of the hole in the preforming die 40 is
_D20 . Here, in order to maintain the lubricated surface of the boss 15, D ₁₀ >D ₂₀ is satisfied during the preforming, and the top portion 42 of the preforming die 40 is shaped like an arc.

Therefore, the plate material 1 is set in the preforming die 40, and the preforming punch 3 is inserted from the surface _F1 side of the plate material 1.
0, the boss 15 is formed in the hole of the preforming die 40, and the outer peripheral surface 16 of the boss 15 is formed with the lubricated back surface _F2 of the plate material 1.

In this embodiment, the thickness of the plate material 1 is T, and the height of the cutting edge portion 32 of the preforming punch 30 is t, which is approximately equal to the extrusion amount, so when the preforming is completed, the dimension n (n = T - The constriction 17 of t) will be formed. Here, T=6mm, t=
4.5 mm, and the dimension n of the constricted portion 17 is 1.5 mm. Note that if n is made smaller than 1.5, the effect will be further improved.

In this way, the outer circumferential surface 16 of the boss 15, which becomes the upright surface ₅₀ , is formed using the back surface F2 of the plate 1 without directly punching out the plate 1. That is,
An upright surface 50 extending from the lubricated surface of the plate material 1
It is a feature of this embodiment that .

Next, the plate material 1 on which the raised surface 50 has been formed is set so that the boss 15, that is, the raised surface 50, is accommodated in the hole of the punching die ₄ whose dimensions are diameter D ₂ . Push the boss 1 into the recess 18 from the surface _F1 side of the plate material 1 using a certain punch 3.
Cut 5. In this case, since D ₁ <D ₁₀ and D ₂ <D ₂₀ , there is a clearance C (C=D ₂
−D ₂₀ ) occurs. Therefore, the outer peripheral surface 11 of the blank 10 formed by punching out the boss 15 from the plate material 1 is as follows.
Since it is formed from the upright surface 50, it is in a lubricated state. Moreover, since the cut portion becomes the constricted portion 17, the new surface N can be made narrow.

The appearance of the blank 10 formed in this manner is as shown in FIG. 4A. However, the lubrication treatment layer is not shown. The new surface N consisting of the sheared surface S having the dimension s and the fracture surface B having the dimension b has a dimension n, which is equal to the dimension of the constricted portion 17, and can be made very small with respect to the thickness T of the plate material 1. This relationship is clear from T-t=s+b=n. Moreover, the fracture surface B is inclined in the upper-inward direction as shown in FIG. 4B.

Therefore, even if the blank 10 is set in a forging die 400 similar to the conventional one shown in FIG. 15 and extruded backward with a forging punch 300, lubrication is ensured. That is, forged product 1 in Fig. 5
As shown as 00, the part that contacts the inner wall surface 401 of the forging die 400 is the extended part of the back surface F2 that was lubricated when the plate material ₁ was made, and the new surface N is in contact with the entire surface. This is because only the portion indicated by the dimension y corresponding to the dimension s of the shear plane S becomes the touch portion.

Furthermore, even if the shearing surface S touches the inner wall surface 401, that portion is outside the stress acting area at the time of opening the rearward extrusion, so there will not be enough resistance to affect seizure.

Furthermore, the inner wall surface 401 of the forging die 400
The non-touched portion that does not touch is a portion indicated by a dimension z, which is approximately equal to the dimension b of the fracture surface B of the new surface N.
This can be understood from the relationship y+z+≈T-t=n=s+b. Therefore, the fracture surface B and the shear surface S
The dimension ratio is the dimension of punching die 4 during punching process.
Since it is determined by the ratio of D ₂ and the dimension D ₁ of the punch 3, the dimension s (≒
y) can be made small, ranging from dimensions close to zero to 1 mm. Therefore, the existence of the new surface N can be almost ignored.

Note that the contact portion between the blank 10 and the punch 3 is on the lubricated surface _F1 side of the plate material 1, so there is no problem as in the conventional case.

As described above, according to the first embodiment, the back surface F ₂ of the plate material 1 that has been lubricated by the bossing method
is extended to form the boss 15, and preforming is performed to make the lubricated surface of the upright surface 50 effective and to provide the constricted portion 17. After that, the narrow constriction 17
The blank 10 is formed by punching out the blank 10 using the cut points. Therefore, since the outer circumferential surface 11 of the blank 10 can be treated almost as a lubricated surface,
Good cold forging can be performed even if the product is not relubricated as in the past. In addition, the dimensions D ₂₀ of the preforming die 40 and the punching die 4 are
Depending on the ratio with _D2 , the shear surface S of the new surface N can be made 1 mm or less, so the forging die 400
The portion that touches the inner wall surface 401 of the forging can be further reduced, and from this point of view as well, smooth forging can be performed. Furthermore, since there is no need to relubricate the blank 10, the blanking process to the cold casting process can be performed consistently, making it easy to automate and save labor.

(Second Embodiment) The second embodiment is shown in FIGS. 6 to 9, and this embodiment is a case in which the preforming process is changed from the boss forming method of the first embodiment to a drawing method. . Therefore, a preforming punch 30 having a tapered surface 33 at an angle α on the cutting edge portion 32, and a preforming die 40 having an inner wall surface 41 having a tapered angle β. Preforming is performed using a mold 20. In this embodiment, the diameter D ₁₀ of the preforming punch 30 and the preforming die 4 are
The diameter D ₃₀ of the hole 0 is equal (D ₁₀ =D ₃₀ ), the angles α and β are equal (α=β), and the pushing amount t and the thickness T of the plate 1 are equal (t= The protruding portion 27 formed by T) is configured so that there is no change in volume. In addition, the diameter D ₁₀ of the preforming punch 30 is the diameter of the forging punch 300.
D ₁₀₀ (D ₁₀ >D ₁₀₀ ), and the outer diameter D ₂₀ of the preforming punch 30 and the diameter D ₂ of the punching die 3 are approximately equal (D ₂₀ ≈D ₂ ).

Therefore, the back side _F2 of the plate material 1 is inserted into the preforming die 4.
0, preforming punch 30 from surface F ₁
By pushing in, a protruding portion 27 with an unchanged volume is formed via the constricted portion 25. The side wall surface of this protrusion 27 corresponding to the angle β of the preforming die 40 becomes the upright surface 50. The upright surface 50 becomes a smoothed surface where the back surface _F2 of the plate material 1 is extended, and the lubricating effect is maintained.
After performing the preforming in this manner, the protruding portion 27, that is, the upright surface 50 is accommodated in the hole of the punching die 4, and then punched from the recessed portion 18, as shown in FIG. Push in punch 3 to make blank 1
Shape 0. In this case, the upright surface 50 is an inclined surface with an angle β, and since D ₂₀ ≈D ₂ , the upright surface 50 does not come into contact with the inner wall surface 6 of the punching die 4, so the lubricated surface It will remain as is.

As shown in FIG. 8, the appearance of the blank 10 is such that the part cut by the aperture part 25 has a new surface N.
However, this new surface N appears on an inclined surface going inward from the outer surface 11 and does not occur on the outer surface 11.
Therefore, a blank 10 has been molded which has been entirely lubricated except for this narrow new surface N.

Therefore, the forged product 100 is processed using the forging die 200 shown in FIG. 15 as in the conventional case.
is shown in FIG. In this forging process, the new surface N of the blank 10 is
The inner wall surface 401 of 00 is not touched at all. Therefore, smooth forging processing is possible. In addition, the new surface N
will appear on the horizontal surface of the top 101 of the forged product 100.

According to the second embodiment, it is possible to obtain a blank 10 that can be subjected to the blanking process to the cold forging process in one batch, as in the first embodiment.

Furthermore, since the upright surface 50 is an inclined surface, complete protection of the lubricated surface during the punching process is ensured. Further, since the preforming process is performed by a drawing method, no new surface N is generated on the outer peripheral surface 11 of the blank 10, so that the effectiveness of the forging process with extremely good lubrication is ensured.

In addition, in this example, regardless of the above conditions, t≧T is ideal, and D ₁₀ ≧D ₁₀₀ and D ₂₀
It is valid if ≧D ₂ . It is also possible to set α>β.

(Third Embodiment) The third embodiment is shown in FIGS. 10 to 12, and the preforming process is based on the embodiment shown in FIG. 6 as in the second embodiment. The explanation will be omitted.

In the punching process of the third embodiment, as shown in FIG. 10, a blank 10 is formed using a punch 3 having a stepped portion 5 at its cutting edge portion 32. Other procedures, conditions, etc. are the same as in the second embodiment, so their explanation will be omitted.

Therefore, according to the third embodiment, the blank 10 has the form shown in FIG. 11, with both upper ends rising. As a result, in the forged product 100, the new surface N stands up at the top 101.

Therefore, in the third embodiment as well, as in the case of the second embodiment, it is possible to fully utilize the lubricated surface of the plate material 1 to form a blank 10 that does not require re-lubricating treatment.

Note that, as in the case of the second embodiment, T=6 mm,
Good experimental results have been confirmed up to α = β = 15°, D ₁₀ = 27.7 mm, and D ₂₀ = 25 mm.

In the embodiments described above, preforming was performed by bossing or drawing, but the key point is that
The method is not critical, as it is sufficient to extend the lubricated surface of the plate material to form an upright surface. In addition, the types and shapes of preforming molds and punching molds,
The present invention is applicable regardless of size. Furthermore, it is clear that the latter forging method is not limited to backward extrusion, but can also be applied to the forming of blanks used in forward extrusion. Of course, depending on the degree of processing, supplementary application of lubricant during the forging process is not excluded.

〔Effect of the invention〕

As explained above, the present invention can effectively utilize the lubricated surface of the plate material to form a blank in which the newly formed surface during the punching process hardly comes into direct contact with the forging die, thereby increasing the production efficiency and economy of forging. It has an excellent effect that can be dramatically improved.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram for carrying out the method for forming a forged product according to the present invention, and FIG.
FIG. 3 is a side sectional view of the main parts of a preforming mold suitable for carrying out the first embodiment, and FIG. 3 is a side sectional view of the main parts of a punching die suitable for carrying out the first embodiment. , FIG. 4 shows a blank molded according to the first embodiment, in which A is a sectional view showing the external appearance, and B is a partially broken enlarged view. FIG. 5 is a sectional view of a forged product obtained by processing the blank formed according to the first embodiment, and FIG. 6 is a sectional view of a preforming die for carrying out the second embodiment of the method for forming a punched blank according to the present invention. FIG. 7 is a side cross-sectional view of the main parts of the punching die of the second embodiment, and FIG. 8 is a cross-sectional view showing the appearance of a blank molded according to the second embodiment. , FIG. 9 is a cross-sectional view of a forged product obtained by processing a blank formed according to the second embodiment, and FIG. 10 is a cross-sectional view of a forged product obtained by processing a blank formed according to the second embodiment, and FIG. A side sectional view of the main parts of the mold, FIG. 11 is a sectional view showing the appearance of a blank molded according to the third embodiment,
FIG. 12 is a cross-sectional view of a forged product obtained by processing a blank formed according to the third embodiment, FIG. 13 is a cross-sectional view of the main part of a mold for carrying out the conventional blank forming method, and FIG. Fig. 15 is a cross-sectional view of a forging die, and A shows the blank set in the conventional forming method, and B shows the blank when the forging process is completed. be. 1... Plate material, 2... Die for punching, 3... Punch for punching, 4... Die for punching, 10... Blank,
20... Mold for preforming, 30... Punch for preforming, 40... Die for preforming, 50... Upright surface, 200... Mold for forging.

Claims (1)

[Claims] 1. A method for forming a forged product by forging a blank obtained by punching a lubricated plate material, wherein the lubricated back side of the plate material is placed on the predictive forming die side. After performing preforming by pushing a preforming punch from the front side toward the back side to form an upright surface on which the lubrication treatment is maintained, the upright surface formed by the preforming is The blank is accommodated in a hole of a punching die having a size larger than that of the forming die, and then a punch is pushed in from the front side to punch a blank from the plate material, and after this,
A method for forming a forged product, which comprises placing the blank in a forging die and forging it with a forging punch. 2. In claim 1, the preforming is performed by pushing a cutting edge of a preforming punch, which is larger in size than the hole of the preforming die, from the front side of the plate material to form an outer periphery on the back side of the plate material. A method for forming a forged product, characterized in that the process is carried out by a boss forming process in which a boss is formed into an upright surface while maintaining the above-mentioned lubrication treatment. 3. In claim 1, the preforming is performed by pushing a preforming punch having a tapered shape corresponding to the tapered shape of the preforming die from the front side of the plate material so that the tapered shape is formed on the back side of the plate material. A method for forming a forged product, characterized in that the method is carried out by a drawing process that forms an upright surface that has the same shape and remains lubricated.