JP6252371B2 - Forging mold and forging method - Google Patents

Description

  The present invention relates to a forging die and a forging method.

For mass production of round parts such as round bars, shafts, or cones with flanges, forging dies are attached to two hammers (die forging), and the work material between both hammers facing each other is hit There is a forging machine that passes through and manufactures.
In die forging, a metal material is plastically flowed by applying pressure with a mold or the like to form. Since the fiber flow is continuous, the structure becomes dense, and the cast hole is less likely to be formed compared to casting, so that it is possible to make a shaped material with excellent strength.

  As a background art of the sequential forging die, there is JP-A-48-25650 (Patent Document 1). According to this publication, “the work surface consists of a side surface of an obtuse V-shaped tool groove extending in the rotation direction of a work piece rotating around an axis, and this groove is formed on the wedge toward the prism-like finished portion. In the case of having a narrow entrance portion, in the entrance portion (4), the angle (α) formed by the front work surface (7) and the plane (E) passing through the groove bottom and the work piece surface with respect to the work piece rotation. Is larger than the angle (β) between this plane and the rear work surface (8), whereas the two corners (α ′, β ′) are the same difference in the finished part (3). "A tool for circular forging against a forging machine with only two hammers facing each other."

Japanese Patent Laid-Open No. 48-25650

  Patent Document 1 describes a mold for forging a cylindrical material. However, in the mold described in Patent Document 1, when the amount of reduction per pass increases, the angle difference between the angles α and β of the V-shaped mold groove surface increases, and two surfaces even at the bottom dead center. There was a problem that the molding accuracy was deteriorated.

  An object of the present invention is to provide a sequential forging method and a forging die capable of forging a cylindrical workpiece with high accuracy even when the amount of reduction per pass is large.

  In order to solve the above-described problem, in the present invention, two forging dies for circular forging that are attached to a forging machine so as to face each other are provided with V-shaped grooves formed in the respective dies. And the second processed surface, and the first processed surface that comes into contact with the workpiece first is the metal when rotating the workpiece that is moved by applying rotational feed and longitudinal feed between the molds. The angle β formed with the pressing direction of the mold and the angle α formed with the second processing surface that comes into contact with the workpiece later with the pressing direction of the mold have a relationship of β> α, and the V shape of both molds The bottom of the groove is rotated around the center axis of the workpiece rotating between the two molds from the mold pressing direction by the angle (β-α) / 2 to the second machining surface. It was configured to be formed in a moved arrangement.

  In order to solve the above problems, in the present invention, when the two forging dies for circular forging are attached to a forging machine so as to face each other, V-shaped grooves formed in the respective dies, The first processed surface, the second processed surface, and the bottom of the V-shaped groove were configured to have a rotationally symmetric relationship around the central axis of the workpiece that rotates between both molds.

  In order to solve the above-mentioned problem, in the present invention, the bottoms of the V-shaped grooves of both dies are formed by connecting the first processing surface and the second processing surface with an arc having a predetermined curvature. To be configured.

  In order to solve the above-mentioned problem, in the present invention, a forging machine is attached with a pair of forging dies having V-shaped grooves facing each other with the workpiece sandwiched therebetween, and the workpiece is made of the die. In the forging method for creating an indentation shape, the forging die has a V-shaped groove formed in each die having a first processing surface and a second processing surface, and between the two dies. , The angle β formed by the first working surface in contact with the workpiece first and the pressurizing direction of the mold when rotating the workpiece to which the rotational feed and the longitudinal feed are applied, and the workpiece later The angle α between the second processing surface in contact with the mold and the pressing direction of the mold is in a relationship of β> α, and the bottoms of the V-shaped grooves of both molds rotate and move between the molds. Around the central axis of the workpiece to be processed, and arranged so as to be rotated and moved to the second processing surface side by an angle (β−α) / 2 from the pressing direction of the mold. The work material was disposed between them, and the work material was pushed in with the two dies while being rotated and fed in the longitudinal direction.

According to the present invention, it is possible to provide a sequential forging method and a forging die capable of forging a cylindrical workpiece with high accuracy.
Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

It is a perspective view explaining the sequential forging method which reduces a cylindrical workpiece. It is sectional drawing explaining the sequential forging method which reduces a cylindrical raw material. It is sectional drawing which shows the relationship between the metal mold | die shape and raw material shape in the sequential forging method which reduces a cylindrical raw material. It is sectional drawing which shows the relationship between the metal mold | die shape and raw material shape in the sequential forging method which reduces a cylindrical raw material. It is sectional drawing which shows the relationship between the metal mold | die shape and raw material shape in the sequential forging method which reduces a cylindrical raw material. It is sectional drawing which shows the relationship between the metal mold | die shape and raw material shape in the sequential forging method which reduces a cylindrical raw material. It is a figure explaining the effect of the metallic mold and forging method of the present invention. It is a perspective view of the metal mold | die shape in the sequential forging method which reduces a cylindrical raw material. It is an example of sectional drawing of a pair of forging metal mold | die arrange | positioned facing.

Hereinafter, examples will be described with reference to the drawings.
FIG. 1 shows a die 11a in a forging machine according to the present embodiment, in which a cylindrical material (workpiece) 1 is held by a manipulator (not shown) and attached to two upper and lower hammers (not shown). It is a perspective view explaining the sequential forging method which strikes the workpiece 1 by 11b and reduces the diameter.

The longitudinal direction of the workpiece 1 is the x-axis direction, the pressing direction of the pair of molds 11a and 11b is the z-axis direction, and the x-axis direction and the direction orthogonal to the z-axis direction are the y-axis direction. The pair of molds 11a and 11b are arranged in a state of facing each other with the workpiece 1 interposed therebetween. The mold 11a and the mold 11b are simultaneously moved toward the center of the workpiece 1, and the 12,13 workpiece 1 is pressed down. Thereafter, the workpiece 1 is sent in the x-axis direction and the material 1 is sent around the x-axis. And it repeats that metal mold | die 11a and metal mold | die 11b move to the center direction of the workpiece 1 simultaneously, and press down the workpiece | work 12,13.
The step of feeding the workpiece 1 in the x-axis direction and the step of rotating the workpiece 1 around the x-axis are not necessarily simultaneous, but from the viewpoint of reducing the machining time, the workpiece 1 is moved along the x-axis. It is preferable to simultaneously perform the step of feeding in the direction and the step of rotating the workpiece 1 around the x axis.

FIG. 2 is an example of deformation of the workpiece 1 when the cylindrical workpiece 1 is forged using a pair of molds 11 having V-shaped grooves 21. 2A is a cross-sectional view immediately before pressurizing the cylindrical workpiece 1 with a mold 11 having a V-shaped groove 21, and FIG. 2B is pressed in FIG. 2A. Thereafter, the mold 11 is moved in the z-axis direction so as to be away from the workpiece 1, the workpiece 1 is rotated about the x-axis in the clockwise direction on the paper, and the mold 11 is brought closer to the workpiece 1 again. FIG. 3 is a cross-sectional view immediately before pressing the workpiece 1 with a mold 11 having a V-shaped groove 21 after moving in the z-axis direction.
The workpiece 1 pressed in the state of FIG. 2 (A) has a workpiece corner 2 pressed near the bottom 22 of the V-shaped groove and a flat surface 23 of the V-shaped groove. It consists of a pressed workpiece flat portion 3 and a workpiece corner portion 5 that connects the workpiece flat portion 3 and the workpiece arc 4. When the pressed workpiece 1 is rotated about the x axis as shown in FIG. 2B, the cross-sectional shape of the workpiece 1 becomes asymmetric with the V-shaped groove on the zy plane, and the workpiece The corner 2 and the workpiece corner 5 are pressed against the mold 11 in an asymmetric state. For this reason, the shaping | molding precision of the cross-sectional shape of the workpiece 1 forged falls.

FIG. 3 is an example of a mold in which the angle of the processed surface of the V-shaped groove for forging the cylindrical workpiece 1 is changed. FIG. 3 shows the processing surface 23a of the V-shaped groove of the mold 11 and the pressing direction 14 of the mold 11 (the upper and lower molds 11 are simultaneously pressed in the z-axis direction, and the upper and lower molds 11 The angle formed by the line 14 connecting the bottom 22 of the V-shaped groove and the pressing direction 14) is α, and the V-shaped groove processed surface 23b of the mold 11 and the mold 11 are formed. It is a cross-sectional view of the arrangement of the upper and lower molds 11 where β is the angle formed with the pressing direction of β and β> α. The processing surfaces of the upper and lower molds 11 are in a relationship of rotation targets around the rotation axis (x axis) of the workpiece 1.
In the shape of these molds 11, when the difference between the angles α and β formed between the processed surfaces 23 a and 23 b of the V-shaped groove and the pressing direction of the mold 11 increases, the processed surface 23 a of the V-shaped groove. Even if only the side is in contact with the workpiece 1 and the deformation on the processing surface 23a side is caused by pressurization, the processing surface 23b side of the V-shaped groove is not in contact with the processing material 1, so the upper and lower molds 11 The forging is performed on two of the processed surfaces 23a, and the forming accuracy is lowered.

FIG. 4 is an example of a mold for forging the cylindrical workpiece 1 following the example of FIG. 4, the angle formed by the processing surface 23a of the V-shaped groove of the mold 11 and the pressing direction 14 of the mold 11 is α, and the processing surface of the V-shaped groove of the mold 11 is compared with FIG. 23 is a cross-sectional view of the arrangement of the upper and lower molds 11 where β is the angle formed by the pressing direction 14 of the mold 11 and β> α, and the bottom 22 of the V-shaped groove is the mold 11. FIG. 6 is a transverse cross-sectional view arranged at a position rotated about the central axis 9 of the workpiece 1 from the pressing direction 14 by (β−α) / 2. As a result, even when the difference between the angles α and β formed by the processing surfaces 23a and 23b of the V-shaped groove and the pressing direction 14 of the mold 11 is increased, the V-shaped groove of the upper and lower molds 11 is processed. Since the surface 23a and the processed surface 23b of the V-shaped groove are in contact with the workpiece 1, forging is performed on the processed surface 4 of the V-shaped groove, and the forming accuracy is improved.
The rotation of the workpiece 1 is given in the clockwise direction on the paper surface. When the workpiece 1 is rotated, the machining surface that comes into contact with the workpiece 1 first is 23b, and the machining surface that comes into contact later is 23a. is there. The same applies to other figures thereafter.

FIG. 5 is an example of a mold for forging the cylindrical workpiece 1 following the example of FIG. In FIG. 5, as in FIG. 4, the angle formed by the processed surface 23 a of the V-shaped groove of the mold 11 and the pressing direction 14 of the mold 11 is α, and the V-shaped groove of the mold 11 is The angle between the processing surface 23b and the pressing direction 14 of the mold 11 is β, and the bottom 22 of the V-shaped groove is (β−α) / 2 from the pressing direction 14 of the mold 11 to be processed. 1 is arranged at a position rotated around the center axis 9 toward the machining surface 23a side to be contacted later, and the width direction end 24a of the upper mold 11 is more than the other width direction end 24b. It is a cross-sectional view arranged on the side of the central axis 9 of the workpiece 1. As a result, even if the difference between the angles α and β formed by the processing surfaces 23a and 23b of the V-shaped groove and the pressing direction 14 of the mold 11 increases, the processing surfaces 23a and 23b of the V-shaped groove The difference between the widths 25a and 25b can be reduced, and the workpiece 1 having a large diameter can be forged with high accuracy.
In addition, the shape of the processing surface of the upper and lower molds 11 is related to the rotation target around the rotation axis (x axis) 9 of the workpiece 1.

  FIG. 6 is an example of a mold for forging the cylindrical workpiece 1 following the example of FIG. FIG. 6 is a cross-sectional view similar to FIG. 5, but with the bottom 22 of the V-shaped groove being an arc. By pressing the workpiece 1 with the mold 11 having the bottom 22 of the arcuate V-shaped groove, the arc shape is transferred to the material and the molding accuracy is improved. The curvature of the bottom 22 of the arcuate V-shaped groove is preferably the final dimension of the workpiece 1 to be forged.

  FIG. 7 is a diagram for explaining the effect of the mold of the present invention. In FIG. 7A, the angle formed by the processing surface 23a of the V-shaped groove of the mold 11 and the pressing direction 14 of the mold 11 is α, and the processing surface 23b of the V-shaped groove of the mold 11 The angle formed by the pressing direction 14 of the mold 11 is β, and the bottom portion (arc-shaped) 22 of the V-shaped groove comes into contact later by (β−α) / 2 from the pressing direction 14 of the mold 11. FIG. 3 is a cross-sectional view in which a bottom surface 22 of a V-shaped groove is an arc disposed at a position rotated around the central axis 9 of the workpiece 11 on the processing surface 23a side. About this shape, the effect was compared by the finite element forging analysis simulation. The condition was that the mold 11 was pushed in the direction of the workpiece 1 and the diameter of the workpiece 1 was reduced from 220 mm to 200 mm. The rotational feed around the x axis was set to 30 °, and pressurization by the mold 11 and rotational feed around the x axis were repeated five times. The angle formed by the machining surface 23a of the V-shaped groove of the mold 11 and the pressing direction 14 of the mold 11 is α, and the processing surface 23b of the V-shaped groove of the mold 11 and the pressing of the mold 11 are performed. When the angle formed by the direction 14 is β and expressed as (α, β), Condition 1 is (40 °, 80 °), Condition 2 is (60 °, 60 °), and Condition 1 is V-shaped. The bottom 22 of the groove is disposed at a position rotated about the central axis of the workpiece 1 from the pressing direction 14 of the mold 11 by (β−α) / 2.

  In FIG. 7B, the horizontal axis 41 represents the position of the workpiece 1 in the circumferential direction (positional coordinates so that the relative position can be understood), and the vertical axis 42 represents the radius of the workpiece 1. 1 is a graph in which a contour of a surface of 1 is developed in a circumferential direction of a workpiece 1. The unit of the horizontal axis 41 is °, and the unit of the vertical axis 42 is mm. Both conditions 1 and 2 have a shape having two peaks in the circumferential direction. However, it can be confirmed that condition 1 has a smaller absolute value of the peak, and the deformation is gentler and the molding accuracy is better. .

  FIG. 8 is an example of one form of the mold 11 of the present invention. In FIG. 8, the angle formed between the processing surface 23 a of the V-shaped groove of the mold 11 and the pressing direction of the mold 11 is α, and the processing surface 23 b of the V-shaped groove of the mold 11 and the mold 11. Β is the angle formed by the pressing direction, and the bottom 22 of the V-shaped groove continuously extends from the pressing direction of the mold 11 in the x-axis direction, which is the longitudinal direction of the workpiece 1 (β−α). It is arranged at a position rotated about the central axis of the workpiece 1 by / 2. When rotational feed and longitudinal feed are applied to the workpiece 1 for each pressurization by the mold 11, the portion where the workpiece 1 is pressed near the portion processed by the mold 11 is processed. It changes continuously in the longitudinal direction of the material 1. By adopting the shape of the mold 11 as described above, it is possible to perform molding with high accuracy in response to a continuous change in the cross-sectional shape of the workpiece 1.

FIG. 9 shows an example of the AA ′ cross section obtained by cutting the pair of molds 11 a and 11 b shown in FIG. 6 along a plane passing through the central axis 9 of the workpiece 1 and the pressing direction 14 of the mold 11. . A form different from the form shown in FIG. 8 is shown.
In FIG. 9, the cross sections of the upper and lower molds 11 a and 11 b are divided into an inlet part 31, a finishing part 32, and an outlet part 33. The cross-sectional shape of the finishing portion 32 is the same as the final product shape to be finished with these molds, and the inlet portion 31 has a cross-sectional width in a wedge shape in order to pressurize the workpiece 1 and finish to the final shape sequentially. And formed to reduce the depth. Further, the outlet 33 has a taper symmetrical to the inlet 31 and is used as an inlet in the case of return forging in which the feed direction 8 of the workpiece 1 is reversed.
In the cross-sectional view of FIG. 9, the processing surface 23 a is visible on the upper mold 11 a, and the bottom 22 of the V-shaped groove is covered by (β−α) / 2 from the pressing direction of the mold 11. It shows that the workpiece 1 is disposed at a position rotated around the central axis 9.

DESCRIPTION OF SYMBOLS 1 Work material 2 Work material corner part 3 Work material flat part 4 Work material circular part 5 Work material corner part 7 Work material rotation feed 8 Work material longitudinal feed 9 Work material rotation center Shaft 11, 11a, 11b Mold 12, 13 Mold pressing operation 14 Mold pressing direction 15 Line 21 connecting bottom of V-shaped groove V-shaped groove 22 Bottom of V-shaped groove 23 Processing surface 24 of V-shaped groove 24 End portion 25 in mold width direction Processing surface width 31 Inlet portion 32 Finishing portion 33 Outlet portion 41 Horizontal axis 42 Vertical axis

Claims (8)

In two forging dies for circular forging that are mounted opposite to each other on a forging machine,
A V-shaped groove formed in each mold has a first processed surface and a second processed surface,
An angle β between the first mold surface and the pressurizing direction of the mold when the workpiece to be moved is moved by being given a rotational feed and a longitudinal feed between both molds. The angle α formed by the second processing surface that comes into contact with the workpiece later and the pressing direction of the mold has a relationship of β> α, and the bottoms of the V-shaped grooves of both molds are Around the central axis of the workpiece that rotates between the pressurizing direction of the mold and the angle (β-α) / 2 is formed to be arranged to rotate to the second processing surface side The forging die is a feature. When the two forging dies for circular forging are attached to the forging machine opposite to each other,
The V-shaped groove, the first processed surface, the second processed surface, and the bottom of the V-shaped groove formed in each mold are the central axis of the workpiece that rotates between the two molds. The forging die according to claim 1, wherein the forging die has a rotationally symmetric relationship around.   2. A bottom portion of the V-shaped groove of the both dies is configured such that the first machining surface and the second machining surface are continuously formed by an arc having a predetermined curvature. Or a forging die according to claim 2.   The forging die according to claim 1, wherein the height of one end in the width direction of the die having the V-shaped groove is higher than the height of the other end in the width direction.   The forging die according to claim 3, wherein the curvature of the arc that continues the first and second machining surfaces is set close to the curvature of the final product shape. In a forging method in which a pair of forging dies having V-shaped grooves facing each other with a work material sandwiched between forging machines is attached, and the work material is pushed in with the mold to create a shape.
In the forging die, the V-shaped groove formed in each die has a first processing surface and a second processing surface,
An angle β between the first mold surface and the pressurizing direction of the mold when the workpiece to be moved is moved by being given a rotational feed and a longitudinal feed between both molds. The angle α formed by the second processing surface that comes into contact with the workpiece later and the pressing direction of the mold has a relationship of β> α, and the bottoms of the V-shaped grooves of both molds are Around the central axis of the work piece that rotates between and from the pressurizing direction of the mold, it is formed in an arrangement that is rotated and moved to the second work surface side by an angle (β-α) / 2,
A forging method characterized in that the workpiece is disposed between the two dies, the workpiece is rotationally fed, and the two dies are pushed in while providing longitudinal feed. 6. the bottom of the V-shaped groove of the molds, characterized in that the first processing surface and the second processing surface is configured continuously in a circular arc having a predetermined curvature The forging method described in 1. The forging method according to claim 7 , wherein a curvature of an arc continuing the first processed surface and the second processed surface is set close to a curvature of a final product shape.

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