JP6123809B2 - Mold structure for forging - Google Patents

Description

  The present invention relates to a die structure for forging.

  In general, relatively large parts such as engine crankshafts and connecting rods are generally manufactured by hot forging. When manufacturing by forging, each process of crushing forging, rough forging, finish forging and trimming (deburring) of a forged material after roll processing is usually performed in order to obtain a target forged product. Patent Document 1 describes a forging die structure in which dies for each process are arranged side by side on a die cassette on a die holder.

  By the way, forging dies, for example, a high-temperature forging material repeatedly comes into contact with a large load, so that the use conditions are severe. For this reason, when the number of times of use of the mold increases, the cavity surface of the mold deteriorates (wears, heat cracks, etc.), and the desired forged product cannot be obtained. Conventionally, a new cavity surface is formed by performing step-down processing (surface cutting or build-up welding) on the deteriorated cavity surface of the mold, and the mold is reused by raising the step-down portion with a spacer. The technique of doing is adopted.

JP 2008-000792 A

  Although the above-mentioned step-down / reuse increases the life of the mold, it causes a loss of mold operation due to the step-down process, and the step-down process itself is costly. Since the quality of the cavity surface also decreases, the quality of the forged product obtained decreases.

  In order to solve the above problem, the present inventor divides a forging die into a cavity die having a cavity for forming a forged product and a base die for supporting the cavity die. We considered making it disposable when it was deteriorated. According to this, since the step-down process is not required, there is no loss of operation of the mold, the step-down process cost is not required, and the quality of the forged product can be avoided. Further, even if the cavity mold is disposable, the cavity mold itself can be reduced in size, so that an increase in material cost associated with the disposable can be suppressed.

  However, in the case of the above-described mold division structure plan, as shown in FIG. 6, when the cavity mold 1 is made to be disposable so as to be disposable, the thickness of the mold becomes thin. As a result, the tensile stress generated in the cavity mold 1 becomes excessive due to a load (indicated by an arrow) in the separating direction applied to the opposite side surface portions 2a and 2b of the cavity 2 during forging, and the mold crack 3 is likely to occur. In FIG. 6, 4 is a base die, 5 is a forged product, and 6 is a burr of the forged product 5.

  Then, this invention makes it a subject to cope with the mold crack of a cavity type | mold.

  In the present invention, in order to solve the above-described problems, a preload is applied to the cavity mold.

The mold structure for forging disclosed here is
A cavity mold having a cavity for molding a forged product;
A base mold on which the cavity mold is supported;
A first load receiver and a second load receiver which are provided on both sides of the cavity mold and are opposed to each other with the cavity mold interposed therebetween so as to receive a load applied to the opposite side surface portions of the cavity during forging
A preload applying member that is press-fitted between the cavity mold and the first load receiver and applies a compressive load to the cavity mold between the first load receiver and the second load receiver by a wedge action ;
The first load receiver is constituted by another mold provided adjacent to the cavity mold .

With such a forging die structure, since the compressive load is applied to the cavity mold in advance by the wedge action of the preloading member, the tensile force generated in the cavity mold when a load is applied to the opposite side surfaces of the cavity during forging. Stress is reduced. Therefore, cracking of the cavity mold is prevented. In addition, if another mold adjacent to the cavity mold is used as the first load receiver, it is not necessary to provide a load receiving side wall on the base mold, which is advantageous for downsizing the entire transfer press forging device. The adjacent mold can reliably receive the load during forging, which is advantageous for prevention of mold cracking.

  It is preferable that the second load receiver is constituted by another mold provided adjacent to the cavity mold. This eliminates the need to provide a load receiving side wall in the base die, which is advantageous for downsizing the entire transfer press forging device, and can reliably receive the forging load in the adjacent die, This is advantageous for preventing mold cracking.

  Preferably, a clamping member is provided that is fixed to the base mold and clamps the cavity mold between the cavity mold and the another mold (second load receiver), and the another mold includes the clamping member. And receiving a load applied to the side surface of the cavity. As a result, the load applied to the cavity mold during forging can be received by the cooperation of the other mold and the clamping member, which is advantageous in preventing mold cracking.

  In addition, the forging die structure according to another embodiment disclosed herein,
  A cavity mold having a cavity for forging;
  A base mold on which the cavity mold is supported;
  A first load receiver and a second load receiver which are provided on both sides of the cavity mold and are opposed to each other with the cavity mold interposed therebetween so as to receive a load applied to the opposite side surface portions of the cavity during forging;
  A preload applying member that is press-fitted between the cavity mold and the first load receiver and applies a compressive load to the cavity mold between the first load receiver and the second load receiver by a wedge action;
  The second load receiver is constituted by another mold provided adjacent to the cavity mold;
  A clamping member that is fixed to the base mold and clamps the cavity mold between the cavity mold and the another mold as the second load receiver;
  The another mold receives a load applied to the side surface portion of the cavity through the clamping member.

  In such a forging die structure, a compressive load is applied to the cavity mold in advance by the wedge action of the preloading member, so that the tensile force generated in the cavity mold when a load is applied to the opposite side surface of the cavity during forging. Stress is reduced. Therefore, cracking of the cavity mold is prevented.

  Further, since the second load receiver is constituted by another mold adjacent to the cavity mold, it is not necessary to provide a load receiving side wall on the base mold, which is advantageous for downsizing of the entire transfer press forging device. In addition, the adjacent mold can reliably receive the load during forging, which is advantageous in preventing mold cracking. Further, the load applied to the cavity mold at the time of forging can be received by the cooperation of the another mold and the clamping member, which is advantageous in preventing mold cracking.

In each of the forging die structures, a preferred embodiment is such that the cavity mold cavity forges a long object, and the first load receiver and the second load receiver are orthogonal to the longitudinal direction of the cavity. It is arrange | positioned at the both sides of the direction to carry out. A cavity mold that forges long objects is subject to a force that expands the cavity to both sides in the direction perpendicular to the longitudinal direction during forging, and this tends to cause vertical cracks. It is prevented by giving .

Good Mashiino is that the cavity mold is forged with a forging die that follows the shape of the forging products. As a result, forged lines are formed along the cavity surface in the cavity mold, which makes the cavity mold more resistant to repeated bending stresses and is advantageous in preventing mold cracking.

  In a preferred embodiment, the forged product is an engine crankshaft. In the case of a crankshaft, the counterweight portion and the crankpin portion are provided alternately in the axial direction and have a complicated shape, which tends to cause a concentration of tensile stress in the cavity mold during forging. By applying the load, mold cracking is prevented.

  According to the present invention, on both sides of a cavity mold having a cavity for molding a forged product, a first load receiver opposed across the cavity mold so as to receive a load applied to opposite side portions of the cavity during forging, and A second load receiver is provided, a preload applying member is press-fitted between the cavity mold and the first load receiver, and a compressive load is applied to the cavity mold between the first load receiver and the second load receiver by a wedge action. Since this is applied, the tensile stress generated in the cavity mold when a load is applied to the opposite side surfaces of the cavity during forging is reduced, which is advantageous in preventing cracking of the cavity mold.

  Thus, in the case where the first load receiver is constituted by another mold provided adjacent to the cavity mold, there is no need to provide a load receiving side wall on the base mold. This is advantageous for downsizing of the entire apparatus, and the adjacent mold can surely receive a load during forging, which is advantageous for prevention of mold cracking.

  In addition, the second load receiver is constituted by another mold adjacent to the cavity mold, and a clamping member that is fixed to the base mold and clamps the cavity mold between the cavity mold and the another mold. In the case where the other mold receives a load applied to the side surface portion of the cavity via the clamping member, it is not necessary to provide a load receiving side wall on the base mold. In addition to the advantage, the adjacent mold can reliably receive the load during forging, which is advantageous for prevention of mold cracking. Further, the load applied to the cavity mold at the time of forging can be received by the cooperation of the another mold and the clamping member, which is advantageous in preventing mold cracking.

The disassembled perspective view which shows the die structure for forging which concerns on Embodiment 1 of this invention. The perspective view of the metal mold | die structure for the forging. Sectional drawing of the principal part of the metal mold | die structure for the forging. Sectional drawing which shows the metal mold | die structure for forging which concerns on Embodiment 2 of this invention. Sectional drawing which shows a mode that the cavity type | mold which concerns on embodiment of this invention is forged. Sectional drawing which shows a mode that a crack is produced in a cavity type | mold.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

<Embodiment 1>
A forging die structure (lower die device) shown in FIGS. 1 and 2 is for forging a crankshaft of an engine as a long object, and a rough forging die 11 arranged in parallel at an equal pitch, A finish forging die 12 and a trim die 13 are provided. The crushing forging die adjacent to the rough forging die 11 is not shown. The forging dies 11, 12 and the trim die 13 are each attached to a die holder (not shown). Above the lower die device, an upper die device having forging dies and trim punches 20 corresponding to the forging dies 11, 12 and the trim die 13 is provided. Trimming is performed.

  The finish forging die 12 employs a die dividing structure that is divided into a cavity die 15 having a forging cavity 14 and a base die 16 to which the cavity die 15 is attached. On the other hand, unlike the finish forging die 12, the rough forging die 11 of the present embodiment has a cavity portion having a forging cavity 17 and a base portion integrated. The trim die 13 is formed by fixing a trim die 19 having a burr shear blade around an opening corresponding to a product portion of the crankshaft on a cradle 18 that receives a crankshaft after finish forging. 1 and 2 show a state where the trim punch 20 is lowered.

  The cavity die 15 of the finish forging die 12 is fixed to the base die 16 by fasteners 22 arranged at both ends in the cavity longitudinal direction. On both sides of the cavity mold 15 in the direction orthogonal to the longitudinal direction of the cavity, a preload applying member 23 and a clamping member 24 are arranged.

  The preload applying member 23 extends between the cavity mold 15 and the trimming mold 13 between the cavity mold 15 and the trimming mold 13 in the longitudinal direction of the cavity. The preload applying member 23 is fixed to the base mold 16 by a plurality of fasteners 25 arranged at intervals in the cavity longitudinal direction. Similarly, the clamping member 24 is sandwiched between the cavity mold 15 and the rough forging mold 11 and extends in the cavity longitudinal direction. The clamping member 24 is fixed to the base mold 16 by a plurality of fasteners 26 arranged at intervals in the cavity longitudinal direction.

  In the present embodiment, the rough forging die 11 and the trim die 13 are used as a first heavy receiver and a second load receiver that are opposed to each other with the cavity die 15 of the finish forging die 12 interposed therebetween. The compressive load is applied. This will be specifically described below.

  As shown in FIG. 3, the preload applying member 23 is tapered so that the width gradually decreases as it goes downward, and is press-fitted between the cavity die 15 and the trim die 19 of the trim die 13 from above. In this embodiment, the side surfaces 27 and 28 in which the cavity mold 15 and the preload application member 23 come into contact with each other are inclined surfaces, and the side surfaces in which the trim die 19 of the trim mold 13 and the preload application member 23 are in contact with each other are vertical. It has become. The side surfaces of the rough forging die 11 and the clamping member 24 that are in phase contact with each other and the side surfaces of the cavity die 15 and the clamping member 24 that are in phase contact with each other are vertical.

  The preload application member 23 is press-fitted between the cavity mold 15 and the trim die 19 of the trim mold 13, and a compressive load is applied to the cavity mold 15 by the wedge action of the preload application member 23. That is, between the trim mold 13 as the first load receiver adjacent to the cavity mold 15 and the rough forging mold 11 as the second load receiver adjacent to the cavity mold 15, the cavity mold 15 is orthogonal to the longitudinal direction of the cavity. A compressive load in the direction is applied.

  Therefore, during forging with the finish forging die 12, a load in a direction away from each other is applied to the opposing side surface portions 14a and 14b of the cavity 14 in the cavity die 15. The load applied to one side surface portion 14 a is received by the trim die 19 of the trim mold 13 as the first load receiver via the preload applying member 23, and the load applied to the other side surface portion 14 b is the second load via the clamping member 24. It is received by the rough forging die 11 as a receiver. Then, since the compressive load is preliminarily applied to the cavity mold 15 by the preload applying member 23, the load in the separating direction applied to the side surfaces 14a and 14b is partially offset by the compressive load. Become. As a result, since the tensile stress generated in the cavity mold 15 is reduced, vertical cracks are prevented from occurring in the cavity mold 15.

<Embodiment 2>
As shown in FIG. 4, the base die 16 of the finish forging die 12 is provided with side walls 31 and 32 that are opposed to each other in a direction orthogonal to the cavity longitudinal direction. Both side walls 31 and 32 constitute a first load receiver and a second load receiver which are opposed to each other with the cavity mold 15 interposed therebetween. Thus, the tapered preload application member 23 is press-fitted between the cavity mold 15 and the one side wall 31 from above, and is fixed to the bottom of the base mold 16 as in the first embodiment. Thereby, a compressive load in a direction perpendicular to the longitudinal direction of the cavity is applied to the cavity mold 15 between the side walls 31 and 32.

  The preload application member 23 of the present embodiment has its both side surfaces 33 and 34 inclined in opposite directions so that the width gradually decreases as it goes downward. Then, the cavity mold 15 and the one side wall 31 correspond to both side surfaces 33 and 34 of the preload applying member 23 so that the distance between the cavity mold 15 and the one side wall 31 gradually becomes narrower downward. The opposite side surfaces 35 and 36 are inclined in the opposite direction.

  Therefore, also in the present embodiment, the load in the separating direction applied to the side surface portions 14a and 14b of the cavity 14 in the cavity mold 15 during forging is partially offset by the compressive load previously applied to the cavity mold 15. Become. Therefore, the tensile stress generated in the cavity mold 15 is reduced, and vertical cracks are prevented from occurring in the cavity mold 15.

<About cavity mold 15>
After the cavity mold 15 is formed by casting, the inner surface of the cavity 14 is molded using a forging mold 37 that follows the shape of the crankshaft. As a result, as shown in FIG. 5, since the forging line (fiber flow) 38 is formed in the cavity mold 15 along the inner surface of the cavity 14, the cavity mold 15 is resistant to repeated bending stress, and the above-mentioned pre- Combined with load cancellation by compressive load, it is advantageous for prevention of mold cracking.

<Other embodiments>
In the first embodiment, the preload application member 23 is tapered with only one side surface as an inclined surface. However, when the preload application member 23 is tapered, both side surfaces may be inclined surfaces.

  Also, the rough forging die 11 adopts a die split structure composed of a cavity die and a base die, and a precompression load is applied to the cavity die in the same manner as in the first and second embodiments. May be.

  Further, in the finish forging die or the rough forging die of the upper die apparatus, a mold dividing structure may be adopted in accordance with the first and second embodiments, and a precompression load may be applied to the cavity die.

11 Rough forging die (second load receiver)
12 Finish forging die 13 Trim die (first load receiver)
14 Cavity 14a Side face part 14b Side face part 15 Cavity mold 16 Base mold 23 Preloading member 24 Nipping member 31 Side wall (first load receiver)
32 Side wall (second load receiver)

Claims (7)

A cavity mold having a cavity for forging;
A base mold on which the cavity mold is supported;
A first load receiver and a second load receiver which are provided on both sides of the cavity mold and are opposed to each other with the cavity mold interposed therebetween so as to receive a load applied to the opposite side surface portions of the cavity during forging
A preload applying member that is press-fitted between the cavity mold and the first load receiver and applies a compressive load to the cavity mold between the first load receiver and the second load receiver by a wedge action ;
The forging die structure , wherein the first load receiver is constituted by another die provided adjacent to the cavity die. In claim 1 ,
The forging die structure, wherein the second load receiver is constituted by another die provided adjacent to the cavity die. In claim 2 ,
A clamping member that is fixed to the base mold and clamps the cavity mold between the cavity mold and the another mold as the second load receiver;
The forging die structure, wherein the another die receives a load applied to the side surface portion of the cavity through the clamping member. A cavity mold having a cavity for forging;
A base mold on which the cavity mold is supported;
A first load receiver and a second load receiver which are provided on both sides of the cavity mold and are opposed to each other with the cavity mold interposed therebetween so as to receive a load applied to the opposite side surface portions of the cavity during forging;
A preload applying member that is press-fitted between the cavity mold and the first load receiver and applies a compressive load to the cavity mold between the first load receiver and the second load receiver by a wedge action;
The second load receiver is constituted by another mold provided adjacent to the cavity mold, and is fixed to the base mold between the cavity mold and the another mold as the second load receiver. A clamping member for clamping the cavity mold
The forging die structure, wherein the another die receives a load applied to the side surface portion of the cavity through the clamping member. In any one of Claims 1 thru | or 4 ,
The cavity type cavity is for forging long objects,
The die structure for forging, wherein the first load receiver and the second load receiver are disposed on both sides in a direction orthogonal to the longitudinal direction of the cavity. In any one of Claims 1 thru | or 5 ,
The cavity type, forging die structure characterized by being forged with a forging die that follows the shape of the forging products. In any one of Claims 1 thru | or 6 ,
Forging die structure characterized by forging engine crankshaft.

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