JPH07144247A - Die for forging part with steps and method thereof - Google Patents

Abstract

PURPOSE:To reduce by half of process number in a forging process, reduce the machining cost and improve the life of die. CONSTITUTION:In order to forge a part with steps having a first small diameter part 2, a large diameter part 4 and a second small diameter part 3 on a lower step part, a middle step part and an upper step part in its axial direction with one process, an annular taper hole 28 which connects to the upper end of a first small diameter hole 27 of a lower die 20 and inclines so that the diameter is made larger facing toward the upper side is preliminarily formed, and an annular taper surface 46 which inclines so that the diameter is made smaller facing toward the upper side is preliminarily formed. Then, the taper hole 28 promotes the flow of raw material into the first small diameter part 2, and the taper surface 46 promotes the flow of raw material into the second small diameter part 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a forging process for a shaft-shaped or tubular stepped component having a first small diameter portion, a large diameter portion, and a second small diameter portion in the axial lower step portion, middle step portion, and upper step portion, respectively. Forging die and method for forging, particularly to forging die for stepped component and forging apparatus for stepped component capable of forging-forming a first small diameter portion, a large diameter portion and a second small diameter portion in one step .

[0002]

2. Description of the Related Art Conventionally, forging is used as an output gear of a mission of an automobile, in which a first small diameter portion, a large diameter portion, and a second small diameter portion are formed in an axial lower step portion, a middle step portion, and an upper step portion, respectively. As a stepped component which is a product, there is, for example, one shown in FIG. The stepped component 100 includes a first small diameter portion 101 at an axial lower step portion and a large diameter portion 102 at an axial middle step portion.
And a second small diameter portion 103 in the axially upper step portion,
The large diameter portion 102 and the first and second small diameter portions 101 and 103 are
The first and second small diameter portions 101 and 103 are connected integrally via first and second annular taper portions 104 and 105 that are inclined so that the diameter gradually increases toward the large diameter portion.
This stepped component 100 becomes a finished product by forming a tooth profile on a large diameter portion by cutting after forging.

Conventionally, such a stepped component 1
00 uses the cylindrical forging material 110 shown in FIG. 4,
In the first step as shown in FIG. 5, the first small diameter portion 101 and the first annular taper portion 104 of the lower step portion are first forged and then in the second step as shown in FIG. 2 The small diameter portion 103 and the second annular taper portion 105 were forged.

[0004]

As described above, since the conventional forging of the stepped component 100 is performed in the two steps of the first step and the second step, the number of steps is large and the processing cost is high. There was a problem that was high. An object of the present invention is to provide a method for forging a stepped component that can reduce the number of forging steps, can be forged in one step, and can reduce the processing cost.

[0005]

A forging die for a stepped component according to a first aspect of the present invention is provided with a first axial step lower part, a middle step part and an upper step part, respectively.
A forging die for forging a shaft-shaped or tubular stepped component having a small diameter portion, a large diameter portion, and a second small diameter portion, wherein the lower die of the forging die has a first small diameter portion. A first small-diameter hole for forming, an annular taper hole connected to the upper end of the first small-diameter hole and inclined to increase the diameter upward, and a large-diameter part connected to the upper end of the tapered hole The upper die punch of the forging die has a second small diameter hole for forming the second small diameter portion, and is slidably fitted in the large diameter hole. It is characterized in that it is formed in a tubular shape, and an annular tapered surface is formed at the lower end thereof so as to be inclined so as to have a smaller diameter toward the upper side.

According to a second aspect of the present invention, there is provided a method for forging a stepped component, wherein the axially lower step portion, middle step portion and upper step portion respectively have a first small diameter portion, a large diameter portion,
A method of forging a shaft-shaped or tubular stepped component having a second small-diameter portion in one step, comprising a first small-diameter hole for forming the first small-diameter portion and an upper end of the first small-diameter hole. Connected to
A lower die having an annular tapered hole inclined so as to have a larger diameter toward the upper side, and a large diameter hole connected to the upper end of the tapered hole for forming a large diameter portion, and the second small diameter portion. Has a second small-diameter hole for molding, and is formed in a cylindrical shape to be slidably fitted in the large-diameter hole, and has an annular taper inclined at the lower end so as to decrease in diameter upward. And an upper die punch having a surface formed thereon to promote the flow of the forging material into the first small diameter hole through the inclination of the taper hole of the lower die and the second die through the tapered surface of the upper die punch. It is characterized by promoting the flow of the forged material into the small diameter hole. Here, when the length of the first small diameter portion is larger than the length of the second small diameter portion, the inclination angle of the tapered hole is set to be larger than the inclination angle of the tapered surface (claim dependent on claim 2). 3) You can.

[0007]

According to the forging die of the stepped component of the first aspect, the forging material is set in the large diameter hole of the lower die, and the upper die punch is lowered with respect to the lower die to obtain the upper die. The tubular portion of the punch is inserted into the large-diameter hole of the lower die so as to be fitted therein, and the forging material is pressed by the tubular portion to be molded. During this molding,
A part of the forging material is guided by the inclined surface of the taper hole of the lower die and flows into the first small diameter hole. Further, a part of this forging material is guided by the annular taper surface of the lower end portion of the tubular portion of the upper die punch and flows to the second small diameter portion. Thus, a stepped component in which the first small diameter portion is formed in the axial lower step portion, the large diameter portion is formed in the axial middle step portion, and the second small diameter portion is formed in the axial upper step portion is obtained. In this way, since this stepped component can be forged in one step, the number of steps for forging can be reduced and the processing cost can be reduced.

In the method for forging a stepped component according to claim 2, the same action and effect as those of the forging die can be obtained. Further, the inclined taper hole of the lower die facilitates the flow of the forging material to the first small diameter hole, and the inclined taper surface of the upper die punch flows the forging material to the second small diameter hole. As a result, a molded product having no wall thickness can be obtained, the forging processing force at the time of forging is reduced, and seizure between the die and the forging material does not occur, and the die life can be improved. .

Here, in the forging method of claim 3,
By setting the inclination angle of the tapered hole to be larger than the inclination angle of the tapered surface, the flow of the forged material on the inclined surface of the tapered hole can be promoted more than the flow of the forged material on the tapered surface. The length can be made larger than the length of the second small diameter portion. Also, the first
By appropriately setting the inclination angle of the taper hole and the inclination angle of the taper surface according to the length of the small diameter portion and the length of the second small diameter portion, a molded product having no thin wall is forged in one step. be able to.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is an example in which the present invention is applied to a forging die and a forging method for forging a stepped component which is a forged product such as an output gear of an automobile mission. As shown in FIG. 3, the stepped component 1 includes a first small diameter portion 2 at an axial lower step portion, a large diameter portion 4 at an axial middle step portion, and a second small diameter portion 3 at an axial upper step portion. The through hole 7 is provided in the axial center portion.

As shown in FIGS. 1 and 2, a lower die 20 of a forging die 11 of a forging device 10 for forging a stepped component 1 which is a forging product is a die having a forming hole 21 in the center. 22, the mandrel 24 inserted and mounted in the central through hole 30 of the die 22, and the die 22 on the lower set plate 2
5, the lower set plate 25 is fixed to the base member 12 of the forging device 10. The forming hole 21 of the die 22 is the first small diameter hole 27.
And an annular taper hole 28 that is continuous with the upper end of the first small diameter hole 27 and is inclined so as to increase in diameter upward.
The tapered hole 28 has a large-diameter hole 29 connected to the upper end thereof.

Further, the upper die 40 of the forging die 11 of the forging device 10 has a punch 42 having a tubular portion 41 at the lower end which is fitted in the large diameter hole 29 in a sliding contact manner, and the punch 42. Holder 44 for fixing the to the upper set plate 43
And the upper set plate 43 is fixed to the ram member 13 of the forging device 10. On the mandrel 24,
A lower large diameter portion 31 internally fitted in a central through hole 30 of the die 22 (which has the same diameter as the first small diameter hole 27 and continues to the lower end thereof) and a bottom surface of the first small diameter hole 27 are formed. Step 32
And a small diameter part 33 connected to the upper part through this step part 32.
And are formed.

A second small diameter hole 45 having a diameter substantially the same as that of the first small diameter hole 27 is formed inside the tubular portion 41 of the punch 42, and the lower end is inclined so as to be reduced in diameter upward. An annular tapered surface 46 is formed. The annular tapered surface 46 and the tapered hole 28 have their respective inclination angles set appropriately in advance in accordance with the shape of the stepped component 1 to be forged, for the reason described in the manufacturing method described later. That is, the inclination angle θ1 of the annular tapered hole 28 is
The size is preset to a size corresponding to the length h1 of the first small diameter portion 2 of the stepped component 1, and the inclination angle θ2 of the annular tapered surface 46 is the axial direction of the second small diameter portion 3 of the stepped component 1. Length h
The size is set in advance according to 2.

In this embodiment, since the axial length h1 of the first small diameter portion 2 is longer than the axial length h2 of the second small diameter portion 3, the inclination angle θ1 of the annular tapered hole 28 is an annular shape. Is formed to be larger than the inclination angle θ2 of the taper surface 46, and in the stepped component 1, the first annular taper portion 5 that is continuous from the large diameter portion 4 to the first small diameter portion 2 is formed to have the inclination angle θ1. A second annular taper portion 6 connecting the diameter portion 4 to the second small diameter portion 3 is formed at an inclination angle θ2.

In the case of this embodiment, in FIG. 3, the axial length h1 of the first small diameter portion 2 is about 34 mm, the axial length h2 of the second small diameter portion 3 is about 24 mm, and the first lower portion The inclination angle θ1 of the annular taper portion 5 is set to 30 °, and the inclination angle θ2 of the upper second annular taper portion 6 is set to 15 °.

Next, a forging method for forging the stepped component 1 using the forging die 11 composed of the lower die 20 and the upper die 40 will be described. First, the tubular forging material 8
Then, the forging material 8 is set in the large diameter hole 29 portion of the forming hole 21 of the die 22 while penetrating the small diameter portion 33 of the mandrel 24. Next, the ram member 13 is lowered, and the punch 4 is moved through the upper set plate 43 and the punch holder 44.
2 is lowered and the cylindrical portion 41 of the punch 42 is moved to the die 2
It is inserted into the large-diameter hole 29 of the second forming hole 21 so as to be fitted therein, and is pushed into the outer peripheral portion of the forging material 8.

Then, as shown in FIG. 2, when the forging material 8 is pressed by the tubular portion 41 of the punch 42, the lower side portion of the forging material 8 becomes an inclined surface of the tapered hole 28 of the forming hole 21. The flow is accelerated by being guided to flow into the first small diameter hole 27 to form the first small diameter portion 2, and the upper side portion of the forging material 8 has an annular tapered surface 46 of the tubular portion 41 of the punch 42.
The fluid is promoted by being guided by, and flows into the second small diameter hole 45 to form the second small diameter portion 3 in the axially upper step portion, and the forging material 8
The large-diameter portion 4 is formed integrally with the first and second small-diameter portions 2 and 3 by the axial middle portion of the small-diameter portion 33 of the mandrel 24.
Thus, the through hole 7 is formed.

At the time of this forging forming, as described above, the taper hole 2 of the forming hole 21 of the die 22 is larger than the inclination angle of the annular taper surface 46 of the lower end surface of the cylindrical portion 41 of the punch 42.
Since the inclination angle of 8 is larger, the flow of the forging material 8 into the first small diameter hole 27 is promoted more than the flow of the forging material 8 into the second small diameter hole 45. As a result, the axial length h1 of the first small diameter portion 2 of the forged stepped component 1
Is longer than the axial length h2 of the second small diameter portion 3. In the case of this embodiment, the flow of the forging material 8 is promoted by the taper hole 28 of the forming hole 21 of the die 22 and the flow of the forging material 8 is made by the annular taper surface 46 of the lower end surface of the cylindrical portion 41 of the punch 42. Stepped part 1 because it is larger than promotion
The first small diameter portion 2 is longer than the second small diameter portion 3.

Here, when it is desired to make the axial length of the second small diameter portion 3 of the stepped component 1 longer than the axial length of the first small diameter portion 2, the taper of the molding hole 21 of the die 22 is performed. The inclination angle of the annular taper surface 46 at the lower end surface of the tubular portion 41 of the punch 42 may be made larger than the inclination angle of the hole 28. In addition, these inclination angles are
It is desirable to set it appropriately in relation to the length of the second small diameter portions 2 and 3. As described above, the size of the inclination angle of the tapered hole 28 of the forming hole 21 of the die 22 and the punch 4 are
By appropriately setting the size of the inclination angle of the annular taper surface 46 of the lower end surface of the second tubular portion 41, the stepped component 1
It is possible to freely set the length dimensions of the first small diameter portion 2 and the second small diameter portion 3 and perform forging.

As described above, after the stepped component 1 is forged, the upper die 40 is raised and the stepped component 1 is moved to the lower die 20.
Eject and take out. After that, at the cutting station, a stepped portion used as an output gear of an automobile mission by forming a tooth profile on the outer peripheral portion of the large diameter portion 4 of the stepped component 1 or cutting the outer peripheral surface. A finished product of parts is obtained.

According to the forging die for the stepped component and the method for forging the stepped component described above, the large-diameter portion 4 of the axially intermediate step portion is used.
Since the first small diameter portion 2 of the axial lower step portion and the second small diameter portion 3 of the axial upper step portion can be simultaneously forged, and the stepped component 1 can be forged in one step. The number of steps can be halved and the processing cost can be reduced. Moreover, since the annular tapered surface 46 of the lower end surface of the cylindrical portion 41 of the punch 42 and the tapered hole 28 of the forming hole 21 of the die 22 promote the flow of the forging material 8 during the forging, It is possible to reduce the forging processing force, and it is possible to prevent seizure between the die 11 and the forging material 8 and improve the die life.

Further, the tapered hole 2 of the molding hole of the die 22 is used.
8 and the size of the inclination angle of the annular taper surface 46 of the lower end surface of the tubular portion 41 of the punch 42 are appropriately set in advance, so that the first small diameter portion 2 and the first small diameter portion 2 of the stepped component 1 and 2 The axial length of the small diameter portion 3 can be freely set. In addition, in the above-mentioned embodiment, the forging die of the cylindrical stepped component 1 in which the through hole 7 is formed in the axial center portion and the method of forging the stepped component have been described, but the present invention is not limited to this. For example, by using the mandrel 24 having no small diameter portion 33, the mandrel 24 can be applied to a forging die and a forging method for obtaining a solid stepped component.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an upper die, a lower die and a forging material according to an embodiment.

FIG. 2 is a vertical cross-sectional view showing a state in which a stepped component is molded by the upper die and the lower die of the forging device of FIG.

FIG. 3 is a vertical cross-sectional view of a stepped component formed by an upper die and a lower die of the forging device of FIG.

FIG. 4 is a vertical sectional view of a forging material according to a conventional technique.

FIG. 5 is a vertical cross-sectional view of a forged product that is forged in the first step of the conventional forging method.

FIG. 6 is a vertical cross-sectional view of a forged product that is forged in the second step of the conventional forging method.

[Explanation of symbols]

 1 stepped part 2 1st small diameter part 3 2nd small diameter part 4 large diameter part 8 forging material 11 forging die 20 lower mold 22 die 27 first small diameter hole 28 taper hole 29 large diameter hole 40 upper mold 41 tubular part 42 Punch 45 Second small diameter hole 46 Annular taper surface

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication B21K 1/30 A 8824-4E (72) Inventor Mikio Tomita 1844 Iida Hachihonmatsu-cho, Hiroshima Prefecture Hiroshima 1844 Factory Hachihonmatsu Factory (72) Inventor Kazuya Ito 1844 Iida, Hachimotomatsu-cho, Higashihiroshima City, Hiroshima Prefecture

Claims (3)

[Claims] 1. A forging die for forging a shaft-shaped or tubular stepped component having a first small diameter portion, a large diameter portion, and a second small diameter portion at an axial lower step portion, a middle step portion, and an upper step portion, respectively. The lower die of the forging die is connected to the first small diameter hole for forming the first small diameter portion and the upper end of the first small diameter hole, and is inclined so that the diameter increases upward. The upper die punch of the forging die has a second small diameter portion for forming a second small diameter portion. It has a small-diameter hole and is formed into a cylindrical shape that is slidably fitted into the large-diameter hole, and at its lower end, an annular tapered surface is formed that is inclined so as to decrease in diameter upward. , A forging die for stepped parts characterized by the following. 2. A method for forging a shaft-shaped or tubular stepped component having a first small-diameter portion, a large-diameter portion, and a second small-diameter portion in the axial lower step portion, middle step portion, and upper step portion, respectively, in one step. There is a first small diameter hole for forming the first small diameter portion and the first small diameter hole.
A lower die that is connected to the upper end of a small diameter hole and has an annular tapered hole that is inclined so as to increase in diameter upward, and a large diameter hole that is connected to the upper end of this tapered hole and that forms a large diameter portion. And a second small-diameter hole for molding the second small-diameter portion, and is formed into a cylindrical shape that is slidably fitted in the large-diameter hole, and the lower end portion has a smaller diameter toward the upper side. And an upper die punch having an inclined annular taper surface formed as described above, promoting the flow of the forging material to the first small diameter hole through the inclination of the taper hole of the lower die, and A method for forging a stepped component, characterized in that the flow of the forging material into the second small diameter hole is promoted through the tapered surface. 3. The inclination angle of the tapered hole is set to be larger than the inclination angle of the tapered surface when the length of the first small diameter portion is larger than the length of the second small diameter portion. The method for forging a stepped component according to 2.