JP2002126847A - Cold forging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly precisely form a work by a cold (or hot) forging device. SOLUTION: The forging device is provided with a preliminary compression section (5), in which a raw material (40) is compressed more than the plastic workable stress (T1) by the preliminary compressing section (5), and a pressing section (10), which is operated concurrently with the above process or thereafter, the pressing part (41) of the raw material (40) is pressed by a die (12a) to deform the part to shape the form of die (12a).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold (or warm) forging apparatus for forging a material at room temperature or below a recrystallization temperature.

[0002]

2. Description of the Related Art Conventionally, a mold has been suddenly pressed against a raw material (including an intermediate product which has been preliminarily molded) and forged.

[0003]

In the above conventional apparatus, the material is largely plastically deformed by the pressing of a mold (die), and the degree of unevenness in the deformation causes the degree of internal work hardening of the material to vary, and the friction causes the material to be hardly deformed. Produces a uniform pressure distribution,
When the pressurization of the mold is released, the elastic recovery of the molded part becomes the material,
The molds were mixed and could not be forged with high precision. The present invention provides a cold forging method in which a material is compressed in advance to a stress that can be subjected to plastic working or more, and then a mold is pressed against the material to plastically deform the portion, thereby enabling high-precision forging even with a small deformation. The aim is to obtain a device.

[0004]

Means for Solving the Problems The present invention is configured as follows to achieve the above object. That is, the invention according to claim 1 includes a pre-compression portion for compressing a material to a stress higher than a plastic workable stress, and simultaneously or after the material is pre-compressed to a plastic workable stress or more by the pre-compression portion. A configuration is provided in which a mold is pressed against a molding part and a pressure molding part for deforming this part into the shape of the mold is provided.
Further, the invention according to claim 2 is characterized in that a pre-compression portion for compressing the material in the axial direction to a stress higher than the plastic workable stress, and simultaneously or after the material is pre-compressed to the plastic workable stress or more by the pre-compression portion, And a press-molding section for pressing the mold against the molded section from a direction orthogonal to the axial direction of the mold and deforming the section into the shape of the mold. Claim 3
According to the invention, a pre-compression portion for compressing a material in an axial direction by a first punch and a counter punch opposed to each other, and an outer peripheral portion of an annular ring shape having a molded portion formed on an inner periphery are taperedly fitted to a clamp. A press-molding unit that moves the ring mold in an axial direction in which the tapered surface is reduced with respect to a clamp by a second punch to elastically deform the ring mold in an axial direction; A punch driving device for driving a second punch, wherein the punch driving device moves the first punch in a counterpunch direction so that the material can be plastically worked with the first punch and the counter punch in an axial direction higher than a stress capable of being plastically processed. Simultaneously with or after the pre-compression, the second punch is moved in the axial direction in which the tapered surface is reduced to elastically deform the ring die in the axial direction, and the molded portion is formed on the outer peripheral portion of the material. Attach to it the outer peripheral portion that was configured to deform in a shape corresponding to the molding part. According to a fourth aspect of the present invention, the first punch and the counter punch oppose each other to form a pre-compression portion for compressing the annular material in the axial direction, and an annular ring-shaped shaft center having a molded portion formed on the outer periphery. A pressure-molding section that is taperedly fitted to a cored bar, moves the ring die axially with respect to the cored bar to expand the tapered surface with the second punch, and elastically deforms the ring die radially outward. And a punch driving device for driving the first punch and the second punch, wherein the punch driving device moves the first punch in a counter punch direction to
Simultaneously with or after axially pre-compressing the annular material with a punch and a counter punch at a stress higher than the stress capable of plastic working, the second punch is moved in the axial direction in which the tapered surface expands, and the ring die is radially expanded. In this configuration, the molded portion is elastically deformed outward in the direction, and the molded portion is pressed against the inner peripheral portion of the annular material to deform the inner peripheral portion into a shape corresponding to the molded portion.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, FIG. 1 is a cross-sectional view of a main part in a material pre-compression state according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part in a molded state according to the first embodiment of the present invention, and FIG. FIG. 4 is a sectional view of a main part of a material pre-compressed state according to a second embodiment.
FIG. 5 is a sectional view of a main part in a molded state according to a second embodiment of the present invention, and FIG. 5 is a graph showing a deformation stress-strain characteristic of a material according to the present invention.

In FIG. 1, reference numeral 1 denotes a cold forging device for finish-molding an external gear, in which a cylindrical core 3 is erected on the center of a pressure receiving plate 2 and an annular material is mounted on the core 3. 40 is fitted. This material 40 is formed of an annular intermediate external gear having coarse teeth (molded portion) 41 formed on the outer periphery. A precompression unit 5 for precompressing the material 40 is provided on the outer peripheral side of the cored bar 3. The pre-compression unit 5 has a cylindrical counter punch 6 standing and mounted on the pressure receiving plate 2 concentrically with the metal core 3, and a first cylindrical punch 7 is disposed above the counter punch 6 so as to face the same. The first punch 7 is moved downward by a punch driving device 8 composed of a ram, and the material 40 is compressed in the axial direction by the first punch 7 and the counter punch 6.

On the outer peripheral side of the pre-compression section 5, a pressure molding section 10 for finishing the coarse teeth 41 of the material 40 is provided. The pressure-molding unit 10 has an annular clamp 11 placed on the outer peripheral portion of the pressure receiving plate 2, and an annular ring mold 12 formed on the inner peripheral side of the clamp 11 via a tapered surface 13 whose lower part is reduced. To make a taper fit. The ring mold 12 has coarse teeth 41 of the material 40 on its inner periphery.
Has a molding tooth (molding portion) 12a meshed therewith, is moved downward in the clamp 11 by the second punch 14 arranged above, is elastically deformed in the axial direction via the tapered surface 13, and has an inner periphery thereof. The molding teeth 12a on the side are the coarse teeth 41 of the material 40.
Is pressed in the axial direction to finish-mold it.

The second punch 14 is moved downward by a punch driving device 8 for moving the first punch 7 up and down. The timing of the downward movement of the ring die 12 by the second punch 14 is set as follows. That is, the first
The punch 7 moves downward, and the compressive stress (upsetting pressure) of the material 40 in the axial direction of the material 40 by the first punch 7 and the counter punch 6 is changed according to the deformation stress-strain characteristic line S in FIG. When the compressive stress T1 (strain amount C) at which plastic working can be performed is exceeded, for example, when the material of the material 40 is SC
In the case of M420 steel, about 441 mega Pa (about 45k
g / mm ² ), the second
The punch 14 collides with the ring mold 12 and moves the ring mold 12 downward with respect to the clamp 11, so that the ring mold 12 is
3 is set so as to be elastically deformed in the axial center direction.

The pressure receiving plate 2 located below the ring mold 12
A stopper ring 15 is placed on the lower side, and the amount of downward movement of the ring mold 12 is regulated by the stopper ring 15 at a predetermined value. In this example, as shown in FIG. 5, the height of the stopper ring 15 is set so that the amount of elastic strain A in the axial direction of the ring mold 12 is about 1% or less. As a result, the material 40 is pre-compressed in the axial direction by the first punch 7 and the counter punch 6 at a compressive stress T1 or more at which plastic working is possible, and when the amount of strain in the axial direction becomes C or more,
The ring punch 12 is elastically deformed in the axial direction by about 1% or less (A) by the second punch 14 through the tapered surface 13 of the clamp 11, and the material 40 is formed by the molding teeth 12a of the inner peripheral portion.
Are compressed in the axial direction by the compressive stress T2.

According to the first embodiment, the molded teeth 12a are pressed against the coarse teeth 41 of the raw material 40 after the raw material 40 is pre-compressed to a stress higher than the plastic working stress.
Even if the amount of strain B of the coarse teeth 41 pressed and deformed by the molded teeth 12a is very small, the coarse teeth 41 are likely to be permanently deformed (plastically deformed), and after the pressurization by the first and second punches 7 and 14 is released. In this case, the strain amount B 'corresponding to the above-described strain amount B is held, so that the tooth shape of the molded tooth 12a is accurately captured. In this case, since the ring mold 12 is elastically deformed in the axial direction via the tapered surface 13, the angle and the axial (vertical) surface shape of the tapered surface 13 are made to be convex or concave. The amount of elastic deformation in the axial direction of the upper and lower portions of the ring mold 12 can be appropriately adjusted, and the coarse teeth 41 are crown teeth in which the thickness of the central portion in the vertical direction is gradually increased, or the tooth thickness in the entire upper and lower regions is equal. Can be easily made into straight teeth.

In this embodiment, the second punch 14 is a ring type 1
Although the first punch 7 is continuously lowered even when the second punch 7 is pushed down, this is because the first and second punches 7, 1
4 may be driven alone, and when the second punch 14 is pushing down the ring mold 12, the first punch 7 may be stopped in a state where the raw material 40 is pre-compressed to a stress higher than the plastic workable stress. Alternatively, the counter punch 6 and the first punch 7 may be moved in the contact and separation directions in synchronization with each other, and the material 40 may be pre-compressed by both.

FIGS. 3 and 4 show a second embodiment of the present invention.
3 and 4, reference numeral 20 denotes a cold forging device for finish-molding the internal gear, and a ring-shaped clamp 22 is placed on an outer peripheral portion of a pressure receiving plate 21, and a material is provided on an inner peripheral side of the clamp 22. 45 is fitted. This material 45 is formed of an annular intermediate internal gear with coarse teeth 46 formed on the inner periphery. A pre-compression unit 23 for pre-compressing the material 45 is provided on the inner peripheral side of the clamp 22. The pre-compression unit 23 places a cylindrical counter punch 24 upright on the pressure receiving plate 21 concentrically with the clamp 22, and disposes a cylindrical first punch 25 above the counter punch 24, The first punch 25 is moved downward by a punch driving device 26 composed of a ram, and the material 45 is axially compressed by the first punch 25 and the counter punch 24.

On the inner peripheral side of the pre-compression section 23, a pressure molding section 30 for finishing the coarse teeth 46 of the material 45 is provided. The pressure forming section 30 has a core metal 31 placed on the axis of the pressure receiving plate 21, and an annular ring mold 32 formed on the upper side of the core metal 31 via a tapered surface 33 whose upper part is reduced. Fit.
The ring mold 32 has molding teeth 32a on its inner periphery where the coarse teeth 46 of the material 45 mesh with each other. The ring mold 32 is moved downward along the metal core 31 by the second punch 34 arranged above, and is moved through the tapered surface 33. The material is elastically deformed radially outward, and the molding teeth 32a on the outer peripheral side press the coarse teeth 46 of the material 45 radially outward to finish-mold the coarse teeth 46.

The second punch 34 is moved downward by a punch driving device 26 that moves the first punch 25 up and down. The timing of the downward movement of the ring mold 32 by the second punch 34 is set in the same manner as in the first embodiment. That is, the first punch 25 moves downward,
When the compressive stress (upsetting pressure) of the material 45 in the axial direction by the punch 25 and the counter punch 24 becomes equal to or more than the compressive stress T1 at which the material 45 can be subjected to plastic working as shown in FIG. The punch 34 collides with the ring mold 32 and moves it downward with respect to the metal core 31, so that the ring mold 32 is elastically deformed radially outward through the tapered surface 33.

The pressure receiving plate 2 located below the ring mold 32
A stopper ring 35 is placed on the first member 1, and the amount of downward movement of the ring mold 32 is regulated by the stopper ring 35 at a predetermined value. In this example, as shown in FIG. 5, the height of the stopper ring 35 is set so that the amount of elastic strain A radially outward of the ring mold 32 is about 1% or less. Thereby, the first punch 25 and the counter punch 2
4, the material 45 is pre-compressed in the axial direction at a compressive stress T1 or more at which plastic working is possible, and when the amount of strain in the axial direction becomes C or more, the taper surface 33 of the core metal 31 is removed by the second punch 34. The ring mold 32 is elastically deformed radially outward by about 1% or less (A), and the coarse teeth 46 of the material 45 are radially outwardly compressed by the compression teeth T2 by the molding teeth 32a on the outer periphery thereof. .

According to the second embodiment, the molded teeth 32a are pressed against the coarse teeth 46 of the material 45 after the material 45 is pre-compressed to a stress higher than the stress capable of plastic working.
Even if the amount of strain B of the coarse tooth 46 pressed and deformed by the molding teeth 32a is very small, it is likely to be permanently deformed (plastically deformed), and after the pressing by the first and second punches 25 and 34 is released. In this case, the strain amount B ′ corresponding to the above-described strain amount B is held, and the tooth shape of the molded tooth 32a is accurately captured. In this case, since the ring mold 45 is elastically deformed radially outward through the tapered surface 33, the angle of the tapered surface 33 and the surface shape in the axial direction (vertical direction) are set similarly to the first embodiment. By providing a convex surface or a concave surface, the amount of elastic deformation of the upper and lower portions of the ring mold 45 in the axial direction can be appropriately adjusted.
The crown tooth where the tooth thickness at the center of the vertical direction gradually increases,
Alternatively, it is easy to form straight teeth in which the tooth thicknesses of the entire upper and lower regions are equal.

In this embodiment, the first and second punches 25 and 34 are used.
May be driven alone, and when the second punch 34 is pushing down the ring mold 32, the first punch 25 may be stopped in a state where the material 45 has been pre-compressed to a stress higher than the stress capable of plastic working. The counter punch 24 and the first punch 2
5 may be moved in the contact / separation direction in synchronization with each other, and the material 45 may be pre-compressed by both.

[0018]

As is apparent from the above description, claim 1
In the invention according to the present invention, the material is pre-compressed to a stress higher than the plastic workable stress, or simultaneously or thereafter, the mold is pressed against the material to deform this part into the shape of the mold, so that the amount of strain due to the mold is very small. However, it is easy to permanently deform (plastically deform), and the material can be molded with high accuracy by a cold (or warm) forging device. The invention according to claim 2 is
Simultaneously or after the material is pre-compressed in the axial direction beyond the stress capable of plastic working, the mold is pressed against the material from a direction perpendicular to the axial direction to deform this part into the shape of the mold, so cold forging The outer peripheral surface or the inner peripheral surface of the material can be molded with high precision by the device. Further, the invention according to claim 3 is characterized in that the material is pre-compressed in the axial direction by the first punch and the counter punch, and at the same time or thereafter, the ring punch having the molded portion on the inner periphery by the second punch is used as a clamp. By moving along the taper surface and elastically deforming the ring mold in the axial direction and pressing the molded part against the outer peripheral part of the material, it has a simple structure and forged molding of the outer peripheral surface of the material with high precision Can be. According to a fourth aspect of the present invention, the material is pre-compressed in the axial direction by the first punch and the counter punch, and at the same time or thereafter, the ring punch having a molding portion on the outer periphery by the second punch is tapered to the core metal. The ring mold is elastically deformed radially outward by pressing the molded part against the inner peripheral part of the material, so that the inner peripheral surface of the material can be precisely formed with a simple structure. Can be forged.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part in a pre-compressed state of a material according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part in a molded state according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main part of a material pre-compression state according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part in a molded state according to a second embodiment of the present invention.

FIG. 5 is a deformation stress-strain characteristic diagram of a material according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold forging apparatus which finish-molds an external gear 2 Pressure receiving plate 3 Core 5 Precompression part 6 Counter punch 7 First punch 8 Punch drive 10 Pressure molding part 11 Clamp 12 Ring type 12a Molding teeth (molding part) 13) Tapered surface 14 Second punch 15 Stopper ring 20 Cold forging device for finish forming internal gear 21 Pressure receiving plate 22 Clamp 23 Precompression unit 24 Counter punch 25 First punch 26 Punch driving device 30 Press forming unit 31 Core metal 32 Ring type 32a Molded teeth (molded portion) 33 Tapered surface 34 Second punch 35 Stopper ring 40 (45) Material 41 (46) Coarse tooth (molded portion) S Material deformation stress-strain characteristic line T1 Plastic working Possible compressive stress T2 type compressive stress A type elastic strain B type coarse tooth (material) strain B 'coarse tooth Permanent strain amount (plastic deformation) amount of strain of the material at the time C precompression

Claims (4)

[Claims] 1. A stress (T1) enabling plastic working of a material (40).
A pre-compression portion (5) for compressing the material, and simultaneously or after the material (40) is pre-compressed by the pre-compression portion (5) to a plastic workable stress (T1) or more. A cold forging apparatus comprising: a press forming part (10) for pressing a mold (12a) against a part (41) to deform this part into the shape of the mold (12a). 2. A stress (T1) enabling plastic working of the material (40).
The pre-compression part (5) for compressing in the axial direction as described above, and the material (40) can be subjected to plastic working stress (T1) by the pre-compression part (5).
Simultaneously with or after the pre-compression as described above, the molded part (41) is formed from a direction orthogonal to the axial direction of the material (40).
And a pressure forming part (10) for pressing the mold (12a) to deform the part into the shape of the mold (12a). 3. A pre-compression section (5) for compressing a material (40) in an axial direction by a first punch (7) and a counter punch (6) facing each other, and a molding section (12a) on an inner periphery. The outer peripheral portion of the formed annular ring mold (12) is fitted into the clamp (11) with a taper (13), and the ring mold (12) is fixed to the clamp (11) by the second punch (14). The pressure forming part (1) which moves the tapered surface (13) in the axial direction of contraction to elastically deform the ring mold (12) in the axial direction.
0), the first punch (7) and the second punch (14).
And a punch driving device (8) that drives the first punch (7) and moves the first punch (7) in the direction of the counter punch (6) so as to move the first punch (7) and the counter punch. (6) At the same time as or after the material (40) is pre-compressed in the axial direction beyond the plastically workable stress (T1), the second punch (14) is moved in the axial direction in which the tapered surface (13) is reduced. The ring mold (12) is elastically deformed in the axial direction by moving the molded part (12).
a) pressing the outer peripheral portion (41) of the material (40) to deform the outer peripheral portion (41) into a shape corresponding to the molded portion (12a). 4. A pre-compression portion (23) for compressing an annular material (45) in an axial direction by a first punch (25) and a counter punch (24) facing each other, and a molding portion (32a) on the outer periphery.
The axial center portion of the annular ring mold (32) formed with a taper (33) is fitted to the metal core (31), and the ring mold (3) is fitted.
2) is moved by the second punch (34) with respect to the metal core (31) in the axial direction in which the tapered surface (33) expands to elastically deform the ring mold (32) radially outward. Press forming part (30), the first punch (25) and the second punch (25)
And a punch driving device (26) for driving a punch (34). The punch driving device (26) moves the first punch (25) in the direction of the counter punch (24) to move the first punch (25). ) And the counter punch (24), and simultaneously or after the annular raw material (45) is pre-compressed in the axial direction beyond the plastic workable stress (T1), the second punch (34) is tapered to the tapered surface (33). The ring mold (32) is elastically deformed radially outward by moving it in the axial direction in which it expands, and its molded part (32a) is pressed against the inner peripheral part (46) of the annular material (45). Inner circumference (4
6. A cold forging apparatus characterized in that 6) is deformed into a shape corresponding to the molding portion (32a).