JPH11169999A - Forging die equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely make the center of a hole part for center coincide with the axis of a blank for forging by forming the hole part for center in the center at the one end part along the axial direction of the blank for forging through a projection part under acting of pressurizing force of a punch to the blank for forging. SOLUTION: The forging formation is applied to the blank for forging through the punch, a first die member 20 and a second die member 26 by lowering the punch, and the blank for forging is plastically fluidized along the shape of a cavity 30. At the time of giving the pressurizing force to the blank for forging through the punch, the hole part for center is formed at the center of a shaft part by boring the one end part of the shaft part constituting the blank for forging with the projection part 46 of a knockout pin 32. In this way, the center of the hole part for center formed simultaneously the forming formation is made to coincide precisely with the axis of the blank for forging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forging die apparatus in which a forging material is provided in a cavity formed in a mold member, and the forging material is forged under the action of a punch.

[0002]

2. Description of the Related Art Conventionally, a forging material is inserted into a forging cavity formed in an upper die and a lower die joined to each other, and a pressing force is applied to the forging material via a punch. 2. Description of the Related Art A mold apparatus for forging a material for use into a predetermined shape is known.

[0003] In this type of forging die apparatus according to the prior art, a method is employed in which a forged product is taken out through a knockout pin provided to be able to advance and retreat in a hole of a lower die, as shown in FIG. A cylindrical knockout pin 1 having an outer peripheral surface having substantially the same diameter is formed between a cylindrical knockout pin 1 and a hole 3 of a lower die 2 through which the knockout pin 1 is inserted.
A predetermined clearance D is set.

By the way, when manufacturing an outer cup constituting a constant velocity joint using such a mold apparatus according to the prior art, after forging a billet into a substantially product shape,
For example, in order to perform finishing such as polishing, it is necessary to form a center hole at the center of one end of a shaft constituting the outer cup. In this case, the center hole is formed by machining using a cutting tool such as a drill (including a machining center).

[0005] The center hole serves as a reference for performing grinding or the like on a portion requiring coaxial accuracy in terms of the function of the constant velocity joint. Therefore, the cup portion and the shaft portion constituting the outer cup are used. High coaxial accuracy is required between the center and the center of the center hole.

[0006]

However, in the mold apparatus according to the prior art, when the knockout pin moves forward and backward due to the clearance between the lower die and the hole, play is produced in a direction perpendicular to the axis. Occur.

Therefore, even if a projection for forming a center hole is provided at one end of the knockout pin constituting the mold apparatus according to the prior art, one end of the shaft of the forged outer cup is provided. There is a disadvantage that the center hole cannot be accurately formed at the center of the portion.

In other words, since the center of the center hole formed by the mold apparatus according to the prior art does not coincide with the axis of the outer cup, the center of the center hole is aligned with the axis of the outer cup. Further, there is a disadvantage that the outer peripheral surface of the forged outer cup must be subjected to lace processing with reference to the center hole.

In this case, if the clearance is set to zero in order to prevent the knock-out pin from rattling, the knock-out pin is locked by the hole so that it cannot move forward and backward. On the other hand, if the clearance is made small, there is another disadvantage that it is difficult to move the knockout pin forward and backward under the action of sliding friction against the hole.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-described various disadvantages. The present invention provides a center hole formed simultaneously with forging of a forging material and a center hole formed by the forging. It is an object of the present invention to provide a forging die apparatus capable of accurately matching the center of a portion with an axis of a forging material.

[0011]

In order to achieve the above object, the present invention provides a mold member having a cavity in which a forging material is provided, and a forging material provided in the cavity. A punch that applies a pressing force to the mold, and a pin member that is provided so as to be able to advance and retreat through a hole formed in the mold member that communicates with the cavity, and extrudes a forged product from the cavity. A protrusion is provided at the center of one end edge of the pin member along the axial direction, and one end of the forging material along the axial direction through the protrusion under the action of the pressing force of the punch on the forging material. A center hole is formed at the center of the portion.

In this case, a tapered hole whose diameter gradually changes from one side to the other side is formed in the hole formed in the mold member, and the one end along the axial direction of the pin member is formed in the hole. A taper portion having a shape corresponding to the tapered hole portion is formed, and the protrusion is accurately positioned in advance at the center of the hole portion by engaging the tapered portion with the tapered hole portion.

Therefore, according to the present invention, by applying a pressing force to the forging material via the punch, the desired forging is performed on the forging material, and at the same time, the protrusion is formed. The center hole is accurately formed at the center of one end of the forging material along the axial direction. In other words, the center of the center hole formed at the same time as the forging can be accurately aligned with the axis of the forging material.

After the center hole is formed through the projection of the pin member under the pressing action of the punch, the pin member and the pressing member are separated by the forming load applied to the pin member. The clearance formed therebetween becomes zero and comes into contact. As a result, the molding load applied to the pin member is absorbed through the clearance, so that the pin member can be protected.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a forging die apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 designates a forging die apparatus according to the present embodiment. The forging die apparatus 10 has a plurality of guide means 12a to 12a near four corners.
It has a first die holder 14 on which 12d is erected, and a second die holder 16 and a third die holder 18 provided at the center of the first die holder 14.

A cylindrical first mold member 20 is fixed on the second die holder 16 via a fastening means 22, and the first mold member 20 is provided with a stepped portion of a first hole 24. 1
A cylindrical second member having a smaller diameter than the mold member 20;
The mold member 26 is integrally joined.

The first mold member 20 and the second mold member 2
6 are integrally formed as shown in FIG.
Alternatively, the first mold member 20 and the second mold member 26 may be divided into a plurality of pieces. In addition, the first mold member 20, the second mold member 26, and the first to third die holders 1
The entirety of 4, 16, and 18 functions as a mold member.

In this case, the first mold member 20 and the second
The first hole 24 and the second hole 28 formed in the mold member 26 respectively have cavities 3 in which a forging material is provided.
0 (see FIG. 3), and a knockout pin (pin member) 32 for extruding a forged product from the cavity 30 is provided below the cavity 30 on the second die holder 1.
6 and the third die holder 18 are provided so as to be able to advance and retreat along the hole 34 formed therein. In this cavity 30,
As a forging material, a third molded product 36 as shown in FIG. 6D is loaded.

A curved shoulder 38 having a predetermined radius of curvature is formed on the upper side of the second hole 28 of the second mold member 26, and the upper side of the second hole 28 is formed on the lower side of the second hole 28. , A tapered hole 40 whose diameter gradually increases by a predetermined range is formed. In the second hole 28, the tapered hole 4
The portion above 0 is formed to be larger than the diameter of the tapered hole 40 whose diameter has been increased.

As shown in FIG. 3, the knockout pin 32 has a pin body 42 having substantially the same diameter and formed in a linear cross section, and is formed at one end of the pin body 42 and has a tapered hole. The tapered portion 44 has a diameter gradually increasing upward corresponding to 40 and a projection 46 formed at the center of the upper surface of the tapered portion 44 and protruding by a predetermined length along the axial direction.

Below the knockout pin 32,
The enlarged diameter pin (pressing member) 4 via a predetermined clearance T
8 are spaced apart. Displacement means (not shown) is connected to the diameter-enlarging pin 48, and the diameter-enlarging pin 48 and the knockout pin 32 can be integrally moved forward and backward under the urging action of the displacement means.

The knockout pin 32 has its tapered portion 44 engaged with the tapered hole 40 of the second mold member 26, and a clearance T is formed between the knockout pin 32 and the enlarged diameter pin 48. As a result, the projection 46 is suspended in a pre-positioned state so as to be arranged at the center of the tapered hole 40.

Above a predetermined distance from the first mold member 20, a ram (not shown) of a mechanical press (not shown) is connected to the ram (not shown). A displaceable elevating member 50 is provided. A punch 54 is fixed to the elevating member 50 via a jig 52, and a guide sleeve 56 formed of a cylindrical metal material is fitted on a predetermined portion of an outer peripheral portion of the punch 54.

A graphite 58 is embedded in the guide sleeve 56 through a plurality of holes, and
Lubrication characteristics when press-fitted into the first hole portion 24 can be favorably maintained. The outer diameter of the guide sleeve 56 externally fitted to the punch 54 is equal to the first mold member 2.
The first hole 24 is slightly larger than the inner diameter of the first hole 24.

The guide sleeve 56 is made of, for example, S
It is preferable that the first mold member 20 is formed of a material harder than the guide sleeve 56, such as a metal material such as KD11, FC25, or FC30.

The punch 54 is provided so as to be displaceable along the vertical direction integrally with the elevating member 50 under the guiding action of a plurality of guide means 12a to 12d erected on the first die holder 14.

The forging die apparatus 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation and effect of the apparatus will be described. The following describes an example in which an outer cup forming a constant velocity joint is forged as a forged product.

By performing a first forging process on a cylindrical billet 60 as shown in FIG. 6A by a mold device (not shown), the diameter of the billet 60 is increased through a middle step as shown in FIG. 6B. Different primary molded articles 62 are obtained. Subsequently, after performing the preliminary molding on the primary molded product 62, the secondary forging is performed by another mold device (not shown), thereby forming the disk portion 64 as shown in FIG. 6C. A secondary molded product 68 including the shaft portion 66 is obtained. Further, by performing tertiary forging with another mold device (not shown), a tertiary molded product 36 having a cup portion 72 and a shaft portion 74 as shown in FIG. 6D is obtained.

[0030] Forging die apparatus 10 according to the present embodiment.
In this method, a fourth forging process is performed using the third formed product 36 as a forging material.

In a state where the punch 54 is arranged at a raised position (not shown), a third molded product 36 as a forging material is loaded into the cavity 30 as shown in FIG.
Then, the punch 5 is integrally formed with the elevating member 50 connected to a ram (not shown) under the driving action of a mechanical press (not shown).
4 is lowered to the state shown in FIG. 1 to start forging.

When the punch 54 descends integrally with the elevating member 50, the elevating member 50 and the first die holder 14
A plurality of (for example, four) guide means 12a to 12d provided between the first and second members preferably absorb the lateral biased load.

At the start of forging, the guide sleeve 56 fitted on a part of the outer peripheral surface of the punch 54 enters along the first hole 24 of the first mold member 20, and further the punch 54 By descending, the punch 54 and the guide sleeve 56 are integrally displaced while being pressed into the first hole 24 of the first mold member 20.

In this way, the punch 54 descends,
2 from the molding start position shown in FIG. 2 to the molding end position shown in FIG. 2, forging is performed on the forging material via the punch 54, the first mold member 20 and the second mold member 26. The forging material plastically flows along the shape of the cavity 30.

When a pressing force is applied to the forging material via the punch 54, one end of the shaft portion 74 constituting the forging material is pierced by the projection 46 of the knockout pin 32, so that A center hole 76 is formed at the center of the shaft 74 (see FIG. 5). In this case, since the knockout pin 32 is inserted in a state where the protrusion 46 is positioned in advance so that the protrusion 46 is arranged at the center of the tapered hole 40, the one end of the shaft 74 that constitutes the forging material is inserted. Center hole 76 can be accurately drilled at the center of the hole. In other words, the center of the center hole 76 formed at the same time as the forging can be accurately aligned with the axis of the forging material.

After the forming of the center hole 76 is started, the clearance T between the knockout pin 32 and the enlarged diameter pin 48 becomes zero due to the forming load applied to the knockout pin 32, so that the contact is made. The molding load is supported (see FIG. 5). As a result, the molding load applied to the knockout pin 32 is reduced to the clearance T.
Through the knockout pin 3
2 can be protected.

After the forging is completed in this way, the punch 54 is raised to a predetermined position integrally with the lifting member 50 connected to the ram (not shown) under the driving action of a mechanical press (not shown). Then, the punch 54 and the guide sleeve 56 are separated from the first hole 24 of the first mold member 20, and are in a standby state for the next forging material. Then, under the driving action of a displacement means (not shown),
The forged product 78 (see FIG. 6E) is taken out by integrally raising the knockout pin 32 to the position indicated by the two-dot chain line shown in FIG.

In the present embodiment, when a pressing force is applied to the forging material, the guide sleeve 56 externally fitted to the punch 54 is pressed into the first hole 24 of the first mold member 20. The punch 54 descends while maintaining the press-fit state.

Therefore, in the present embodiment, the first mold member 2
Since the pressing force is applied to the forging material in a state where the punch 54 is press-fitted into the first hole 24 of the No. 0 via the guide sleeve 56, the punch 54 does not misalign in the lateral direction. The axis of the cup portion 80 of the outer cup obtained as the forged product 78, the axis of the shaft portion 82, and the center hole 7
6 can be maintained with high accuracy in coaxiality with the center line (see FIG. 6E).

In the present embodiment, the outer cup constituting the constant velocity joint is used as a material for forging. However, the present invention is not limited to this. It is needless to say that the present invention can be applied to various forged products requiring coaxial accuracy between a part of a part and another part.

[0041]

According to the present invention, the following effects can be obtained.

That is, by applying a pressing force to the forging material via the punch, the desired forging is performed on the forging material, and at the same time, the center hole is formed through the projection. It can be accurately formed at the center of one end of the forging material along the axial direction.

Therefore, the manufacturing process is simplified by omitting the process of forming the center hole by machining. As a result, a step of transferring a forged product from the forging step to the processing machine is not required, so that labor can be reduced, production efficiency can be improved, and manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a forging die apparatus according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view showing a state where a punch descends from a forging start position shown in FIG. 1 and forging is completed.

FIG. 3 is a partially enlarged sectional view of the forging die apparatus shown in FIG.

FIG. 4 is a partially enlarged cross-sectional view showing a state in which a forging material is provided in a cavity.

FIG. 5 is a partially enlarged sectional view showing a state after forging is performed on a forging material.

FIG. 6A to FIG. 6E are explanatory diagrams showing a manufacturing process of an outer cup constituting a constant velocity joint, respectively.

FIG. 7 is an explanatory diagram showing a relationship between a hole formed in a lower die and a knockout pin in a forging die apparatus according to a conventional technique.

[Explanation of symbols]

10 ... Forging die apparatus 12a-12d
... Guide means 14,16,18 ... Die holder 20,26 ... Mold member 24,28,34 ... Hole 30 ... Cavity 32 ... Knockout pin 40 ... Tapered hole 42 ... Pin body 44 ... Tapered part 46 ... Protrusion 48 … Expansion pin 50… Elevating member 54… Punch 56… Guide sleeve

Claims (3)

[Claims] 1. A mold member having a cavity in which a material for forging is provided, a punch for applying a pressing force to the material for forging provided in the cavity, and the mold communicating with the cavity. A pin member provided so as to be able to advance and retreat via a hole formed in the member, and forging a forged product from a cavity; and a projection at the center of one end edge along the axial direction of the pin member. Is provided, and a center hole is formed at the center of one end along the axial direction of the forging material via the protrusion under the action of the pressing force of the punch on the forging material. Forging die equipment. 2. The apparatus according to claim 1, wherein the hole formed in the mold member has a tapered hole whose diameter gradually changes from one side to the other side, and extends along the axial direction of the pin member. A tapered portion having a shape corresponding to the tapered hole is formed at one end, and the protrusion is positioned at the center of the hole by the taper engaging with the tapered hole. A die apparatus for forging, characterized in that: 3. The apparatus according to claim 1, wherein a pressing member for pressing the pin member toward the cavity is provided in the hole formed in the mold member, and the pin member and the pressing member are connected to each other. A forging die apparatus, wherein a clearance is formed between the two.