JP2013056364A - Forging die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forging die capable of forging a workpiece so that any burr may not be formed even under a large load from the workpiece during the compression step.SOLUTION: The forging die includes a first split die 21 and a second split die 22 which are split and juxtaposed in the direction of the compression axis L, while a split joining surface 21a of the first split die 21 and a split joining surface 22a of the second split die 22 are orthogonal to the compression axis L in the assembled condition. The gap dimension between the split joining surface 21a of the first split die 21 and the split joining surface 22a of the second split surface 22 in a lightly contact condition before the assembly is increased outwardly in the radial direction N from innermost edges 21b, 22b on a cavity 11 side with a very small opposing angle θ of 5'-50'.

Description

  The present invention relates to a forging die.

In forging, the load on the mold is greatest during the compression process in which the thickness of the workpiece (material) is reduced by compression, and the large load at that time tends to cause defects in the mold.
Conventionally, in order to receive a large load, a molding die (insert) that forms a cavity is reinforced from the outer peripheral side by, for example, assembling to a case die by shrink fitting, and further, the molding die is compressed during compression. The part which is easy to break was divided into two so as to be juxtaposed in the compression axis direction in advance to release the stress.
For example, as shown in Patent Document 1, a first split mold (first insert) and a second split mold (second insert) are assembled to a case mold.

JP-A-11-221645

However, if the force (preload) for assembling the first split mold and the second split mold to the case mold is large, the joint surfaces of the first split mold and the second split mold partially bite into each other, and plasticity There has been a problem in that the metal mold is damaged due to the deformation, which cannot follow the deformation caused by the molding (stress cannot be released).
The forging die is actually limited in its volume (outer diameter), and it is not allowed to sufficiently reinforce the outer periphery divided into the first divided die and the second divided die with the case die. There are many. In such a case, the assembling force (preload) is weak, and due to the large load received from the workpiece, there is a gap at the innermost edge on the cavity side at the joint between the first split mold and the second split mold. As a result, a part of the workpiece (material) enters the gap, and there is a problem that molding defects such as burrs occur in the molded product.

  Therefore, in the present invention, under the restriction of the volume (outside diameter dimension) of the forging die, the material in the compression process enters from the cavity side between the joining surfaces of the split die and the split die. An object of the present invention is to prevent the occurrence of a large gap (gap) with a simple structure. Another object of the present invention is to prevent, with a simple structure, the occurrence of plastic deformation (biting) due to excessive contact surface pressure locally on the joint surface.

In order to achieve the above object, a forging die according to the present invention includes a first split mold and a second split mold that are divided and arranged in parallel in the compression axis direction, and the first split is in an assembled state. In the forging die in which the split joint surface of the mold and the split joint surface of the second split die are orthogonal to the compression axis, the split of the first split die is performed in a light contact state before assembly. The gap dimension between the joint surface and the split joint surface of the second split mold is configured to increase from the innermost edge on the cavity side toward the radial outer side with a minute facing angle of 5 'to 50'. It is a thing.
Further, in the light contact state, one of the first split type split joint surface and the second split type split joint surface is formed on an orthogonal plane orthogonal to the compression axis, and the other is a gradient. It is formed in a planar shape.
Further, in the assembled state, the contact surface pressure between the divided joint surface of the first divided type and the divided joint surface of the second divided type is configured to be uniform.
Alternatively, in the assembled state, the contact surface pressure between the divided joint surface of the first split type and the split joint surface of the second split type gradually increases as it goes from the radial outer side toward the cavity side. It is comprised so that it may become.

  According to the present invention, during the compression process, no gap is generated between the first split mold and the second split mold, and the workpiece (part) enters between the first split mold and the second split mold. Can be prevented. Further, it is possible to prevent the first split mold and the second split mold from biting into each other at the joint surface and plastically deforming. Furthermore, it is possible to prevent burrs and the like from occurring in the forged product. Further, damage and wear of the joint portion between the first split mold and the second split mold can be prevented, and the mold life can be extended.

It is a simplified front sectional view showing the assembled state of an embodiment of the present invention. It is a simplified front sectional view showing a state before assembly of an embodiment. It is a principal part expanded sectional view of the state before an assembly | attachment. It is a principal part expanded sectional view of the light contact state before an assembly | attachment. It is a principal part expanded sectional view of an assembly state. It is a principal part expanded sectional view for demonstrating the contact surface pressure in a shaping | molding state. It is a principal part expanded sectional view of the assembly | attachment state of other embodiment. It is a principal part expanded sectional view for demonstrating the contact surface pressure in the shaping | molding state of other embodiment. It is a principal part expanded sectional view which shows the light contact state before the assembly | attachment of another embodiment. It is a simplified front sectional view showing another example of the assembled state of the mold. It is a principal part sectional drawing of the state before an assembly | attachment and showing a prior art example. It is a principal part sectional drawing of an assembly state, showing a conventional example. It is principal part sectional drawing which showed the prior art example and demonstrated the force received from a workpiece | work during shaping | molding. It is a principal part sectional drawing which shows a prior art example, and explains the contact surface pressure of a shaping | molding state while showing the conventional problem.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.
In the embodiment shown in FIG. 1, the forging die is assembled into a case die (reinforcing die) 2 so as to be fitted in an inner fitting tightening shape by shrinkage fitting or the like (assembled state). Material) A cylindrical molding die (insert die) 20 that forms a cavity 11 in which W is housed is provided. The molding die 20 is supported by the spacer die 3 from below and is disposed so as to receive a pressing force (downward pressing force) in the direction of the compression axis L applied from the punch 31.
As shown in FIG. 2, the molding die 20 has a cylindrical first divided die (both the upper insert die and the upper nib) in the compression axis L direction in which the punch (punch) 31 reciprocates in the state before assembly. 2) and a cylindrical second divided mold (also referred to as a lower insert mold or a lower nib) 22.

1 and 2, the first split mold 21 includes an inner peripheral surface 21c that forms a part of the cavity 11 in the assembled state, and a split joint surface 21a that joins the second split mold 22 in the assembled state. (Hereinafter also referred to as the first joint surface 21a), and is formed in a cylindrical shape.
The second split mold 22 includes an inner peripheral surface 22c and a bottom face 22f that form a part of the cavity 11 in the assembled state, and a split joint surface 22a that joins the first split mold 21 in the assembled state (hereinafter referred to as a second bond). And a through hole 22d into which a die pin (knockout pin) 32 that is disposed so as to face the punch 31 and can reciprocate in the direction of the compression axis L is inserted, and has a cylindrical shape. Is formed.
As described above, the first split mold 21 and the second split mold 22 are provided in the direction of the compression axis L, and the split joint surface 21a and the split joint surface 22a are in the assembled state. Is orthogonal.

As shown in FIG. 3, the first split mold 21 and the second split mold 22 are arranged with the compression axis L as the common axis, and the first joining surface (the lower surface of the first split mold 21) 21a and the second In the (prepared) state before assembly in which the joint surface (the upper surface of the second split mold 22) 22a is disposed in a face-to-face manner, the first joint surface 21a is an orthogonal plane (hereinafter referred to as an axial center) The second joining surface 22a is formed on the outer side of the axial center plane (radially outward) to a predetermined position Q separated from the innermost edge 22b on the cavity 11 side by a predetermined dimension S. Side) It is formed in a gradient (taper) surface shape that inclines downward toward N.
That is, the second joint surface 22a forms a conical surface. Further, the second joining surface 22a is formed with a minute gradient angle α of 5 ′ to 50 ′ with respect to the axial center orthogonal plane. In addition, it is further desirable that such a small gradient angle α be 10 ′ to 20 ′.

Further, the second split mold 22 has an escape slope surface 22e that slopes downward from the predetermined position Q toward the axial center orthogonal plane outward side (radial outward side) N.
The relief gradient surface 22e is inclined with an escape angle β that is larger than the minute gradient angle α with respect to the axial center orthogonal plane. Specifically, the relief angle β is 1 ° to 60 °.
That is, the upper surface of the second split mold 22 is a bent taper surface (inclined surface) having a second joint surface 22a and a relief slope surface 22e in a continuous state before assembly. Is frustoconical in side view.

4, the innermost edge 21b of the first joint surface 21a and the innermost edge 22b of the second joint surface 22a are in contact with each other before assembly (in the direction of the compression axis L). In a non-pressed state in which no pressing force is applied), the first joint surface 21a is formed in a plane orthogonal to the axial center, and the second joint surface 22a is formed in a gradient surface shape.
In this light contact state, the gap dimension between the first joint surface 21a and the second joint surface 22a is directed from the innermost edge 21b, 22b to the radially outward side (axial center orthogonal plane outward side) N. It is formed so as to increase with a minute facing angle θ of 5 ′ to 50 ′. In addition, it is preferable to form so that it may increase with the minute facing angle (theta) of 10'-20 '. Incidentally, the minute gradient angle α described above corresponds to the minute facing angle θ (equal to each other). In addition, it can be said that the space between the first joint surface 21a and the second joint surface 22a is formed in the shape of an opening in a light cross-sectional front view.

Further, as shown in FIG. 5, in the assembled state, the second joint surface 22a and the first joint surface 21a are pressed against each other and elastically deformed until the stress balance is maintained (equilibrium). The first bonding surface 21a and the second bonding surface 22a are configured to be bonded in a surface contact manner with a very small inclined surface inclined downward from the cavity 11 side toward the radially outer side N. Although not shown, the first joint surface 21a may be pressed downward by the second joint surface 22a and may be inclined downward from the cavity 11 side toward the radial outer side N. In any case, the first bonding surface 21a and the second bonding surface 22a are configured to be bonded in a surface contact manner with an extremely small inclined surface that is inclined outward and downward. (The minute facing angle θ is set.)
It is desirable that the extremely small inclined angle α ′ of the extremely small inclined surface is set to 1 ′ to 40 ′ (the minute facing angle θ is set). More preferably, the extremely small inclination angle α ′ is 2 ′ to 15 ′.
Further, in the assembled state, the contact surface pressure P between the first joint surface 21a and the second joint surface 22a is configured to be uniform.
In the present invention, since the extremely small inclination angle α ′ of the extremely small inclined surface is extremely small in the assembled state, the first joint surface 21a and the second joint surface 22a are in the assembled state, and the compression shaft It may be called orthogonal to the center L.

  In other words, in FIG. 5, the second joint surface 22a is changed from an inclined plane shape before assembly shown by a two-dot chain line to an orthogonal plane shape in an assembled (assembled) state (very small inclination with a reduced inclination angle). It is provided so as to be deformed (elastically deformed) into a planar shape. In other words, in FIG. 4, the second split mold 22 has an axial center orthogonal reference plane Eq indicated by an alternate long and short dash line in the range from the innermost edge 22 b to the predetermined position Q (the axis orthogonal to the mold 20 It has a small convex portion 29 having a triangular cross section (right triangle shape) that protrudes toward the split mold side (upward) of the joining partner rather than the split reference plane.

More specifically, as shown in FIG. 2 to FIG. 1 or as shown in FIG. 4 to FIG. 5, the first and second split molds 21 and 22 are inserted into the case mold 2 and tightened. In general, it is desirable to apply shrink fitting. As shown in FIG. 4 (FIG. 2) to FIG. 5 (FIG. 1), when the case mold 2 is tightened by shrink fitting or the like, the first split mold 21 is slightly elastically deformed into an upward convex shape (mountain shape). Therefore, the lower surface (divided joint surface) 21a of the first split mold 21 is in pressure contact with the split joint surface 22a of the inclined surface inclined downward in the radial direction while approaching a parallel state, as shown in FIG. A uniform (uniform) contact surface pressure P is drawn. Note that, as described above, the reason why the first split mold 21 is elastically deformed slightly upward convexly (mountain shape) is that the lower surface of the second split mold 22 is prevented from being deformed downward by the spacer mold 3. This is because the upper surface of the first split mold 21 is free (no other members are present).
In the present invention, during tightening such as shrink fitting, the first split mold 21 is elastically deformed into an upward convex shape (mountain shape), and the lower surface thereof is also elastically deformed into an upward convex shape. Utilizing cleverness, the split joint surface 22a of the second split mold 22 is formed in advance on the slope surface with the small slope angle α described in FIGS. 3 and 4 and assembled as shown in FIG. It can be said that the contact surface pressure P is made uniform (equal) in the state.

11 to 14 show conventional examples. As shown in FIG. 11, the split joint surface 91a (first joint surface 91a) of the first split mold 91 is an axially orthogonal plane, and the second split is shown. The split joining surface 92a (second joining surface 92a) of the mold 92 is an axially orthogonal plane.
As shown in FIG. 12, in the assembled state, the contact surface pressure P ′ between the first joint surface 91a and the second joint surface 92a gradually decreases as the innermost edge 91b, 92b approaches. Non-uniform). As shown in FIG. 13, the pressing force F from the workpiece W is applied during the compression process for forging the workpiece W with the innermost edges 91b and 92b and the contact surface pressure P 'in the vicinity thereof being small. When the first split mold 91 and the second split mold 92 are received, since the pressing force F is large on the bottom surface 95 side, bowing deformation occurs as indicated by the arrow M, and the second joint surface 92a is formed on the radially inner side (innermost end). Since the edge 92b) moves by a small dimension downward in FIGS. 13 and 14, and the radially outer side tends to move upward in the figure, the contact surface pressure against the first joint surface 91a on the radially outer side further increases. Then, the contact surface pressure P ′ shown in FIG. 12 changes to a contact surface pressure P ″ shown in FIG. That is, the difference in the contact surface pressure between the radially inner side and the radially outer side becomes large, and the contact surface pressure of the innermost edge 92b approaches zero or closes to zero. As shown in FIG. 14, it enters and generates a so-called burr. Furthermore, there is a problem that wear and damage occur in the innermost edges 91b and 92b and in the vicinity thereof, thereby prolonging the life of the mold. Further, in the vicinity of the predetermined position Q ′ (in the vicinity of the outermost edge of the first and second joining surfaces 91a and 92a), the contact surface pressure becomes excessively large, and crushing or plastic deformation such that the split molds bite each other occurs. There is a problem that it occurs and shortens the life of the mold. The conventional problems described with reference to FIGS. 11 to 14 are excellently solved by a simple structure, and the contact surface pressure P is set in the assembled state of FIG. This is achieved by increasing the outer surface in the radial direction with a small facing angle θ of 5 ′ to 50 ′ so as to be uniform (see FIG. 4). Compared with the conventional assembled state of FIG. The contact surface pressure in the vicinity of the inner edges 21b and 22b is increased, and at the same time, the contact surface pressure is decreased at the predetermined position Q.
Even in the present invention, the same phenomenon as in FIG. 13 described in the conventional example occurs, and bow deformation occurs in the arrow M direction. Therefore, as shown in FIGS. 5 to 6, the contact surface pressure distribution changes in the molding state of the forging process (compression process). That is, the surface pressure on the radially inner side decreases and the surface pressure on the radially outer side increases. However, as compared with the change of the conventional example from FIG. 12 to FIG. 14, the compression surface pressure remains on the radially inner side (innermost edges 21b, 22b) as is apparent from FIG. It is possible to prevent a part of the workpiece (material) W from entering and generating burrs while generating the gap (gap) C as shown in FIG. 5, and the surface pressure on the radially outward side (near the predetermined position Q). Is sufficiently smaller than the conventional FIG. 14 and can prevent crushing (plastic deformation) on the joint surfaces 21a and 22a.

In another embodiment, as shown in FIG. 7, in the assembled state, the contact surface pressure P between the first joint surface 21a and the second joint surface 22a is changed from the radial outer side N to the cavity 11 side. It is configured to gradually increase as it goes.
As shown in FIG. 8, the contact surface pressure P between the first joint surface 21a and the second joint surface 22a is made uniform during the compression process for forging the workpiece W.
Compared with FIG. 14 of the conventional example, as is apparent from FIG. 8, the compression surface pressure also remains on the radially inner side (innermost edges 21b, 22b), thereby causing a gap (gap) as shown in FIG. ) It is possible to prevent a part of the workpiece (material) W from entering and generating burrs while generating C, and the surface pressure on the radially outer side (near the predetermined position Q) is higher than that of the conventional FIG. It is possible to prevent the joint surfaces 21a and 22a from being crushed (plastic deformation) by being sufficiently small.

Next, as shown in FIG. 9, in another embodiment, in a light contact state before assembly, the first joint surface 21a is provided in a gradient surface shape, and the second joint surface 22a is formed in a plane orthogonal to the axis. Then, the gap dimension between the first joint surface 21a and the second joint surface 22a increases from the innermost edge 21b, 22b toward the axial center orthogonal plane outward side (radial outward direction) N with a minute facing angle θ. It is formed to do.
Further, in the light contact state, both the first joint surface 21a and the second joint surface 22a are formed in a sloped surface, and in the light contact state before assembly, the above-mentioned gap dimension is the innermost edge 21b. , 22b toward the outer side N of the plane orthogonal to the axial center, it is also preferable to increase it with a small facing angle θ (not shown).

The present invention can be modified in design, and the structure for holding (reinforcing) the radially outer side N of the molding die 20 (the first split die 21 and the second split die 22) is shown in FIG. Thus, not only when assembled to the case mold 2, but as shown in FIG. 10, a cylindrical first reinforcement in which the first split mold 21 is assembled between the molding mold 20 and the case mold 2. A cylinder 51 to which the mold 51 and the second divided mold 22 are assembled may be reinforced by providing the second reinforcing mold 52. That is, the structure (shape) of the mold (member) to which the first split mold 21 and the second split mold 22 are assembled is free.
Further, the escape gradient surface 22e may not be provided in the second split mold 22, and the escape gradient surface may be formed in the first split mold 21. Further, the escape slope surface 22e may be provided on both the first split mold 21 and the second split mold 22. Moreover, although the direction was demonstrated by making the compression axis L into the vertical shape (up-down direction), it is also free to make it horizontal or inclined. Further, it is more preferable that the minute facing angle θ (minute gradient angle α) is 10 ′ to 20 ′. In the present invention, uniform is defined as the difference between the maximum surface pressure and the minimum surface pressure being within 20%.

  As described above, the forging die of the present invention includes the first split die 21 and the second split die 22 that are divided and arranged in parallel in the direction of the compression axis L, and the first split die in the assembled state. In the forging die in which the divided joining surface 21a of 21 and the divided joining surface 22a of the second divided die 22 are orthogonal to the compression axis L, the first divided die 21 is in a light contact state before assembly. The gap size between the divided bonding surface 21a and the divided bonding surface 22a of the second divided mold 22 is a minute face of 5 'to 50' from the innermost edge 21b, 22b on the cavity 11 side toward the radially outer side N. Since it is configured to increase with the angle θ, a gap C (see FIG. 14) is not generated between the first split mold 21 and the second split mold 22 during the compression process, and a part of the work W is partially Intrusion between the first split mold 21 and the second split mold 22 can be prevented. Further, it is not necessary to forcibly assemble the first split mold 21 and the second split mold 22 with a strong force that bites each other and plastically deforms, and the split mold can follow the deformation caused by molding. The cavity can be maintained in an appropriate shape, and processing defects such as generation of burrs can be reduced and processed into a predetermined shape. Further, damage and wear of the joint portion between the first split mold 21 and the second split mold 22 can be prevented, and the mold life can be extended.

  Further, in a light contact state, one of the split joint surface 21a of the first split mold 21 and the split joint surface 22a of the second split mold 22 is formed on an orthogonal plane orthogonal to the compression axis L, and the other is a gradient surface. Since it is formed in a shape, it is easy to manufacture.

  Further, in the assembled state, the contact surface pressure P between the divided joint surface 21a of the first split mold 21 and the split joint surface 22a of the second split mold 22 is configured to be uniform. It is possible to more reliably prevent the gap C from being generated between the divided joining surface 21a of the mold 21 and the divided joining surface 22a of the second divided mold 22, and an appropriate and high quality forged product can be obtained. Moreover, the mold life can be extended.

  Further, in the assembled state, the contact surface pressure P between the split joint surface 21a of the first split mold 21 and the split joint surface 22a of the second split mold 22 gradually increases as it goes from the radial outer side N toward the cavity 11 side. Therefore, it is possible to more reliably prevent the formation of a gap C between the split joint surface 21a of the first split mold 21 and the split joint surface 22a of the second split mold 22 by molding. A good forged product can be obtained. Moreover, the mold life can be extended.

11 cavity
21 First division type
21a Split joint surface
21b Innermost edge
22 Second division type
22a Split joint surface
22b Innermost edge L Compression axis N Radial outer side P Contact surface pressure θ Minute facing angle

Claims (4)

The first split mold (21) and the second split mold (22) which are divided and arranged in parallel in the direction of the compression axis (L) are provided, and in the assembled state, the split joint surface of the first split mold (21) (21a) and the forging die in which the split joint surface (22a) of the second split die (22) is orthogonal to the compression axis (L),
In a light contact state before assembly, the gap dimension between the split joint surface (21a) of the first split mold (21) and the split joint surface (22a) of the second split mold (22) is a cavity ( 11) It is configured so as to increase from the innermost edge (21b) (22b) on the side toward the radially outer side (N) with a minute facing angle (θ) of 5 ′ to 50 ′. Die for forging.   In the light contact state, one of the split joint surface (21a) of the first split mold (21) and the split joint face (22a) of the second split mold (22) is connected to the compression axis (L 2. The forging die according to claim 1, wherein the forging die is formed in an orthogonal plane orthogonal to), and the other is formed in a gradient plane shape.   In the assembled state, the contact surface pressure (P) between the divided joint surface (21a) of the first split mold (21) and the split joint surface (22a) of the second split mold (22) is uniform. The die for forging according to claim 1 or 2 constituted so that it may become.   In the assembled state, the contact surface pressure (P) between the divided joint surface (21a) of the first split mold (21) and the split joint surface (22a) of the second split mold (22) is The forging die according to claim 1 or 2, wherein the forging die is configured to gradually increase from the radial outer side (N) toward the cavity (11).

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