JP3194333B2 - Mold forging method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die forging method for forming a forged product from a crude material by using an impression.

[0002]

2. Description of the Related Art It is usually difficult to form a metal material into a desired shape by die forging in a single molding.
Although multiple moldings are required, the process depends on the cross-sectional area of the forged product. Then, in the final forging, the wasteland is filled into the finish mold impression, and the surplus is extruded as burrs. In this case, it is desirable that the length of the portion extruded as burrs is uniform. Therefore, it is desirable that the rough land shape should be a theoretical rough land shape distributed to the shape closest to the total cross-sectional area of the forged product and the burr.

The theoretical cross-sectional area of a wasteland is represented by the sum of the cross-sectional area of a forged product and the cross-sectional area of a burr. The cross-sectional diagram is used to set a forging process, determine each impression and determine a material size. Used ("Forging die design", published by Forgekenkensha).

[0004]

If the shape of the wasteland is determined based on the concept of the theoretical wasteland, the yield is theoretically 80%.
That is all. However, in reality, the yield is extremely low at 80% or more, and usually 50 to 70%. Moreover, the idea of the theoretical wasteland is applied to a single piece and a symmetrical cross section or the like, and in the case of a two piece or an asymmetric cross section, the idea is difficult to apply, and the yield is extremely high. The current situation is lower.

In other words, when forming an asymmetrical wasteland from a wasteland material using a rough molding die impression, it is difficult to eliminate any underfill in the theoretical wasteland. Inevitably, the yield must be greatly reduced. For example, in the case of two-piece molding, usually, the molding is usually performed in an arrangement in which one is inverted and opposed, but the impression is asymmetric with respect to the center, and as a result, forging is performed on the side where the cross-sectional area of the impression is small. Occasionally, burrs may occur frequently. On the side where the cross-sectional area of the impression is large, it may be underfilled.

The present invention has been made in view of such circumstances, and has as its object to ensure a high yield even when the impression shape is asymmetric, such as when two pieces are taken.

[0007]

A forging method according to the present invention for solving the above-mentioned problems is a rough land forming method in which a rough material formed by crushing a roll material is formed into a rough surface of a predetermined shape by a rough forming die impression. a step, a forging step of forging the forming mold impressions finishing the rough terrain, be more perpendicular cross to the longitudinal direction
In a die forging method that produces a forged product with asymmetrical surfaces, the center of gravity of the cross section perpendicular to the longitudinal direction of the roll material is crushed.
After processing, the position of the center of gravity is
Allowed, and forming as the center of gravity of any of the cross-section of the roughness profile is located substantially on the vertical line of the center of gravity of the cross section of the corresponding rough mold impressions.

When the wasteland forming step is not performed, the low
The rough material formed by crushing
Forged by pressing, the cross section perpendicular to the longitudinal direction is left and right unpaired
In the die forging method to produce a forged product ,
The center of gravity of the section perpendicular to the longitudinal direction is crushed and processed.
Position in the horizontal direction with respect to the longitudinal direction,
Wherein the center of gravity of the cross section at will is formed so as to be located on a substantially vertical line of the center of gravity of the cross section of the corresponding finish mold impressions.

[0009]

According to the die forging method of the present invention, first, a metal material is prepared. As the metal material, generally a cylindrical roll material processed by a roller is used. The shape of the roll material is determined according to the shape of the impression, and in the case of the present invention, since the underfill does not occur and the occurrence of burrs is small, the shape having a cross-sectional area of 100 to 125% of the cross-sectional area of the impression is used. It can be.

The roll material is a rough material having a shape corresponding to the shape of the rough forming die impression or the finish forming die impression. Generally, it is crushed between a crushing mold composed of an upper mold and a lower mold to form a substantially plate shape. Here in the present invention, Russia
The center of gravity of the cross section perpendicular to the longitudinal direction of the
The center of gravity to the left and right with respect to the longitudinal direction.
Formed so that the center of gravity of any cross section of the profile is located on a substantially vertical line with the center of gravity of the corresponding impression section
ing.

That is, the center of gravity of an arbitrary section cut perpendicularly to the longitudinal direction of the crude material is located substantially on the vertical line of the center of gravity of the section of the corresponding impression. The term “substantially on a vertical line” means near the vertical line, and most preferably coincides with the vertical line, but a deviation of about ± 5% is acceptable.

Therefore, the center of gravity of the crude material and the position of the center of gravity of the impression substantially match in the forging direction at any given cross section. I do. In other words, the small-volume impression has the small-volume portion of the coarse material, and the large-volume impression has the large-volume portion of the coarse material. Is also uniform over the entire circumference.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to embodiments and conventional examples. In this embodiment, the present invention is applied to the case of forming an automobile arm. As shown in FIG. 2, one of the arms is turned upside down to face the other.
An impression is formed so that it can be picked up.

First, a roll material 1 shown by a chain line in FIG. 2 is prepared. The roll material 1 has a substantially cylindrical shape processed by a roller, and the cross-sectional area perpendicular to the longitudinal direction is changed according to the cross-sectional area of the impression 2 in FIG. Here, description will be given focusing on the AA cross section of FIG. In the section A-A of the impression 2, as shown in FIG.
0 and the large volume portion 21 are connected by a narrow passage 22.

In the conventional die forging method, as shown in FIG. 4, the center of gravity G of the roll material 1 is located at a position close to the small volume portion 20 of the narrow passage 22 at the AA sectional position, and the space of the impression 2 is formed. Is separated from the center of gravity g. Therefore, when the die forging is performed in this state, the meat of the roll material 1 is divided into the left and right substantially uniformly, so that the small volume portion 20 becomes excessive and the large volume portion 21 becomes insufficient, and the burrs become uneven.

[0016] Also as a Sokatachizai by processing crushing roll material 1 <br/>, no position change of the center of gravity G is because both upper and lower surfaces of the Sokatachizai 10 become parallel with conventional crushing processing. Therefore, as shown in FIG. 5, although the difference can be smaller than that of the roll material 1, there still remains a problem that the small volume portion 20 is slightly excessive and the large volume portion 21 is slightly insufficient. Therefore, in the present embodiment, as shown in FIG. 3, the upper die 30 having a die surface 32 inclined downward to the right at a section equivalent to AA and the lower die 31 having a flat die surface are crushed into the roll material 1. Do. The shape of the inclined mold surface 32 of the upper mold 30 is formed according to the shape of the impression 2. That is, the shape when the roll material 1 is crushed is analyzed by the finite element method (FEM), and the roll material 1 is analyzed.
The crushed product is crushed so that the center of gravity G of an arbitrary cross section of the crushed product matches the center of gravity g of the corresponding cross section of the impression.

This will be described with reference to the drawings. As shown in FIG. 3, the roll material 1 having a circular cross section is pressed by an upper die 30 having a die surface 32 inclined to the right in a cross section corresponding to AA as shown in FIG. Roughly wedge-shaped coarse material 4 with thick left and thin right
Becomes At this time, the center of gravity G of the cross section of the roll material 1 moves to the left in the drawing with the progress of the crushing process, and the coarse material 4 shifts from the position of the center of gravity G of the cross section of the roll material 1 to the left of the drawing. As shown in FIG. 1, when it is arranged in the impression 2, it coincides with the center of gravity g of the cross section of the impression 2. The same is true for any cross section perpendicular to the longitudinal direction.

Incidentally, in FIG. 3, the roll material 1 has an inclined surface 32.
It looks as though it is pressed and moves in the left and right direction,
The inclination direction of the inclined mold surface 32 in an arbitrary cross section is determined according to the shape of the impression 2 as described above, and there is a rightward downward and a leftward downward, so that the roll material 1 does not move. Further, the crushing width of the crude material 4 needs to be inside the impression 2, and the crushing thickness also needs to be a predetermined size or more according to the size of the impression 2. If this condition is not satisfied, the problem can be solved by changing the cross-sectional area of the roll material 1.

The forged raw material 4 obtained as described above is forged by the finish molding impression 2, thereby making it possible to form two arms of FIG. 2 with less burr and high yield. In the above embodiment, the rough shaped material 4 is forged with a finish forming die as it is to obtain a product. However, a rough land can be formed by using a rough land forming die and then forged by a finish forming die.
In this case, the mold surface shape of the upper mold 30 rough mold Inpureshi
By forming in the same manner as described above according to the application, it is possible to form a rough material having a center of gravity that matches the center of gravity of the rough molding impression at an arbitrary cross section, and it is possible to form a rough land with a high yield. .

[0020]

According to the die forging method of the present invention,
Since the underfill defect can be prevented and the burrs can be made uniform, the shape of the material can be reduced as compared with the conventional case, and the yield is remarkably improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a crude material and an impression in one embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an impression and a shape of a material according to an embodiment of the present invention.

FIG. 3 is an explanatory view showing a method for forming a coarse material in one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between an impression and a material in a conventional method.

FIG. 5 is an explanatory diagram showing a relationship between an impression and a coarse material in a conventional method.

[Explanation of symbols]

1: Roll material 2: Impression
4: Rough material 30: Upper die 31: Lower die G,
g: center of gravity

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-168453 (JP, A) JP-A-4-309430 (JP, A) JP-A-1-166842 (JP, A) JP-A-4-16843 55034 (JP, A) JP-A-5-177290 (JP, A) JP-A-7-148542 (JP, A) JP-A-56-45547 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21J 1/00-13/14 B21J 17/00-19/04 B21K 1/00-31/00

Claims (3)

(57) [Claims] 1. A rough land forming step in which a rough material formed by crushing and processing a roll material is formed into a rough ground having a predetermined shape by a rough forming die impression, and forging is performed by forging the rough land with a finish forming die impression. Process , consisting of cutting perpendicular to the longitudinal direction
In a die forging method for manufacturing a forged product having an asymmetrical surface, the center of gravity of a cross section perpendicular to the longitudinal direction of the roll material is crushed and added.
To move the center of gravity in the left-right direction with respect to the longitudinal direction.
Is allowed, die forging method characterized by forming so as to be positioned on a substantially vertical line any position of the center of gravity of the cross section of該荒mold impressions center of gravity of the cross section corresponding crude profile. 2. A rough material formed by crushing and processing a roll material is forged by a finish forming die impression, and is vertically suspended in a longitudinal direction.
In a die forging method for producing a forged product having a right and left asymmetrical cross section, the center of gravity of a cross section perpendicular to the longitudinal direction of the roll material is crushed and added.
To move the center of gravity in the left-right direction with respect to the longitudinal direction.
Is allowed, die forging method characterized by forming so as to be positioned on a substantially vertical line any position of the center of gravity of the partition on the mold impressions of the cross-section gravity center position of the cross section corresponding crude profile. 3. A cross section perpendicular to the longitudinal direction is left-right asymmetric.
The forged product is a two-piece product.
The die forging method according to claim 1 or 2.