JPH02200335A - Manufacture of forged part - Google Patents

Abstract

PURPOSE:To surely give the strength by supporting a blank material on a die of a forging device so that a space is formed between the blank material and a part corresponding to the part of a forged article which necessitates its strength at the time of forging, compressing it with a die and a punch and bringing it to plastic deformation. CONSTITUTION:Each boss part b1 and a blank material end part b2 of a blank material B both correspond to a part which necessitates strength of a locker arm. Subsequently, the forged blank material B is carried into a forging device 1, and supported on a die 2. In this case, the blank material is placed so that a space C is formed between one (lower side) boss part b1 of the blank material B and a first die constituting member 3 provided on the die 2, and also, a space C is formed between the blank material end part b2 and a second die constituting member 4 provided on the die 2, as well. Thereafter, by allowing a punch 5 to descend, a space C is formed between a punch constituting member 6 and the other boss part b1 of the blank material B, as well. Thereafter, by allowing the punch of further descend, the blank material is brought to plastic deformation, and by pushing aside the plastic deformed part to the spaces C, C..., the locker arm is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a method for manufacturing a forged product by forging a blank material cast into a predetermined shape.

(Prior art) Generally, AN-8L-Cu alloy and Al-3i-C
U-Mg alloys have good castability and can obtain excellent strength and toughness through heat treatment, so they have been widely used as alloys for casting rocker arms and other engine parts for automobiles and other vehicles. It is used.

However, in today's world where there is a demand for higher engine output, the rocker arms and the like are exposed to severe conditions during operation, so there is a further demand for improved mechanical properties such as the strength and toughness. Therefore, in order to meet this requirement, for example, as disclosed in Japanese Patent Application Laid-open No. 187539/1987, a blank material is cast from the above-mentioned Al-5t-Cu alloy, and then this blank material is forged. A method is known in which the mechanical properties are improved by doing so.

By the way, if the shape of the forged product to be obtained, that is, the shape of the die and punch of the forging device, is complex, it becomes difficult to stably support the blank material on the die during forging so that it does not wobble. . As shown by the imaginary line in FIG. 2, when the blank material a is supported on the die b in a tilted state from the normal posture shown by the solid line in FIG. Forging defects such as cracks and fogging may occur. Therefore, by casting the blank material in a shape close to that of the forged product and having a thickness larger in the direction of the compressive force that acts during forging than that of the forged product, we can improve the support of the blank material against the die of the forging equipment. It is conceivable that the above-mentioned forging defects such as underfilling, cracking, and fogging can be prevented by stabilizing the forging process.

(Problem to be Solved by the Invention) However, as described above, when a blank material is cast into a shape close to that of a forged product and whose thickness in the direction of the compressive force acting during forging is greater than that of the forged product, Since the blank material is tightly sandwiched between the die and punch of the forging device in the early stage of forging, plastic flow of the blank material during forging is difficult to occur in the compression direction. It becomes impossible to impart the desired strength to the forged parts that have come off.

The present invention has been made in view of these points, and its purpose is to create a shape that is close to that of a forged product, and whose thickness in the direction of the compressive force that acts during forging is greater than that of a forged product. Forging is performed using a blank material that has been cast to be larger in size, and by actively causing plastic flow in the compression direction during forging of the blank material, the relationship between the die and punch of the forging equipment is improved. The objective is to reliably impart the desired strength to parts of the forged product that are outside the parting line.

(Means for Solving the Problem) In order to achieve the above object, the solving means of the present invention is a method of manufacturing a forged product by forging a blank material cast into a predetermined shape. The product is cast in a shape close to that of a forged product, and the thickness in the direction of the compressive force applied during forging is greater than that of the forged product. Next, this blank material is supported on a die of a forging device so that a space is formed between it and the part corresponding to the part of the forged product that requires strength during forging, and the die and punch are A forged product is obtained by compression and plastic deformation.

(Function) With the above configuration, in the method of the present invention, a blank material that is cast in a shape close to that of a forged product and whose thickness in the direction of action of the compressive force that acts during forging is larger than that of the forged product, During forging, the forged product is compressed by the die and punch and plastically deformed while being supported on the die of the forging device so that a space is formed between the parts corresponding to the parts of the forged product that require strength. I am made to do so.

From this, during forging, the plastically deformed portion of the blank material to be plastically deformed fills the space, and therefore plastic flow occurs in the compression direction during forging of the blank material, which causes the die and punch to form a part. This ensures that the desired strength is imparted to the parts of the forged product that are out of line.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIGS. 1(a) and 1(b) show a case where a rocker arm A as an engine part for a vehicle such as an automobile is forged by a forged product manufacturing method according to an embodiment of the present invention. To explain the manufacturing procedure, first, a blank material B is formed into a shape similar to that of rocker arm A using a casting device (not shown), and the compressive force applied during forging is applied in the direction of action (vertical direction in Fig. 1(a)).
The thickness of the rocker arm A is greater than that of the rocker arm A. As a result, the blank material B is formed with boss portions S, B, into which the rocker arm shaft is inserted by post-processing after forging. Also,
The blank end b2 on the left side of FIG. 1 constitutes a portion to which a roller that slides on the cam is attached. Then, each boss part b1 and the blank end b of this blank material B
2 both correspond to parts of the rocker arm A that require strength.

Next, the blank material B cast as described above is carried into the forging device 1 and supported on the die 2 serving as the lower die of the forging device 1. At this time, a space C is formed between the boss part b1 of one side (lower side in FIG. 1 <a>) of the blank material B and the first die component 3 provided on the die 2. In addition, a space C is also formed between the blank end b2 and the second die component 4 provided on the die 2.

Thereafter, as shown by the imaginary line in FIG. 1(a), the punch 5 serving as an upper die, which is disposed above the die 2 so as to be movable up and down, is lowered. As a result, the bunch component 6 provided on the punch 5 and the other (first
A space C is also formed between the boss portion b1 (upper side in Figure (a)).

Thereafter, as shown in FIG. 1(b), the punch 5 is further lowered and the blank material B is inserted between the die 2 and the punch 5.
It is compressed and plastically deformed. At this time, a space C separate from the space C is formed above the space C formed between the blank end b2 and the second die component 4. Then, the plastically deformed portion of the plastically deformed blank material B is pushed into the spaces C, C, . . . to obtain the rocker arm A.

As described above, in this embodiment, the plastically deformed portions of the blank material B that undergo plastic deformation during forging are arranged between the boss portion b1 and the first die component 3, between the boss portion bl and the punch component 6, and between the boss portion b1 and the punch component 6. Since the spaces C, C, . As a result, the desired strength can be reliably imparted to the portion of the rocker arm A that deviates from the parting line between the die 2 and the punch 5.

Next, after raising the punch 5, the rocker arm A
was carried out from the forging device 1 and heated to T6 under predetermined heat treatment conditions.
After the treatment, the flash a+ formed during forging is removed using a trim die (not shown), and the portions corresponding to the boss portions b1 and blank end b2 of the rocker arm A are removed as shown in FIG. In b), as shown by the dashed line, the product is cut and removed by the volume of each space C.

Thereafter, the rocker arm A from which a predetermined amount of the flash al, each boss portion b1, and the blank end portion b2 have been cut and removed is carried into a shot beaning process, the surface is polished, and the forging work is completed.

In addition, in the above-mentioned example, the case where the forged product is a rocker arm A as an engine part for a vehicle such as an automobile is shown.
Needless to say, this is not the only option.

(Effects of the Invention) As explained above, according to the method of the present invention, a blank material to be forged can be made into a shape close to that of a forged product, and the thickness in the direction of the compressive force applied during forging is that of a forged product. Then, this blank material was supported on a die of a forging device so that a space was formed between it and the part corresponding to the part of the forged product that required strength during forging. In this state, the space is filled with the plastically deformed portion of the blank material by compressing and plastically deforming it with the die and punch. Therefore, plastic flow can occur in the compression direction during forging of the blank material, thereby making it possible to reliably impart the desired strength to the portion of the forged product that is outside the parting line between the die and the punch.

[Brief explanation of the drawing]

The drawings show embodiments of the invention and are shown in FIGS. 1(a) and (b).
) are longitudinal sectional views showing the forging device before and after forging, respectively. FIG. 2 is a schematic diagram of a conventional example showing how a blank material is supported on a die during forging. 1...Forging device, 2...Die, 5...Punch, A
...Rocker arm (forged product), B...Blank material,
C... Space.

Claims (1)

[Claims] (1) A method of manufacturing a forged product by forging a blank material cast into a predetermined shape, in which the blank material is shaped close to the shape of the forged product and the thickness in the direction of the compressive force applied during forging is forged. This blank material is then cast onto the die of a forging machine so that a space is formed between it and the part of the forged product that requires strength during forging. In a supported state,
A method for manufacturing a forged product, characterized in that the forged product is obtained by compression and plastic deformation using the die and punch.