JP7008876B2 - Forging method - Google Patents

Description

The present invention relates to a forging method for forging a work.

For example, Japanese Patent Application Laid-Open No. 59-223132 describes a forging method in which a billet (work) is forged using a die provided with an upper die and a lower die capable of forming a molding cavity according to the shape of a molded product. Is disclosed. Each of the upper mold and the lower mold of the mold is provided with a first flat surface, an inclined surface, and a second flat surface. The first flat surface extends from the outer edge of the molding cavity along a direction orthogonal to the mold closing direction. Further, a first gap is formed between the first flat surfaces of the upper mold and the lower mold.

The inclined surface extends in a direction inclined with respect to the extending direction of the first flat surface from the outer edge portion of the first flat surface. Further, the inclined surfaces of the upper die and the lower die extend in substantially the same direction, and an outflow suppressing portion is formed between them. The second flat surface extends from the outer edge of the inclined surface along a direction orthogonal to the mold closing direction. Further, a second gap is formed between the second flat surfaces of the upper mold and the lower mold.

In this forging method, billets whose capacity is distributed according to the shape of the forming cavity are arranged in the forming cavity to close the upper mold and the lower mold. As a result, the billet is filled in the molding cavity, and the meat flows out from the molding cavity toward the first gap.

The meat flowing into the first gap collides with the inclined surface of the upper mold or the lower mold. This can temporarily regulate the outflow of meat from the molding cavity. Therefore, it is possible to satisfactorily fill the molding cavity with billets to improve moldability, reduce the amount of meat flowing out of the molding cavity, and improve the yield.

Then, after the billet is filled in the molding cavity, the surplus meat of the surplus billet flows into the second gap through the outflow suppressing portion. As a result, a forged product (finished molded product) with burrs is formed between the upper mold and the lower mold. This forged product with burrs can be released from the mold by bringing the knockout pin protruding from the first flat surface of the lower mold into contact with the burr portion.

As described above, in the mold in which the outflow suppressing portion is formed, the meat flows out from the first gap to the second gap through the outflow suppressing portion rather than the meat flowing into the first gap from the molding cavity per unit time. The amount of meat is less. That is, the internal pressure of the first gap is higher than the internal pressure of the second gap. Therefore, if the knockout pin is provided so as to be able to project from the first flat surface forming the first gap, meat tends to flow in between the knockout pin and the pin hole, and there is a concern that the ascending / descending of the knockout pin may be hindered. Will end up.

However, if the knockout pin is provided so as to be able to project from the second flat surface instead of the first flat surface, it becomes difficult to release the forged product. Due to the small amount of surplus meat flowing into the second gap through the outflow control portion and the variation in the locations where the surplus meat reaches, the inside of the second gap can withstand the contact of the knockout pin. This is because it is difficult to form a burr portion having a thickness to be obtained.

A main object of the present invention is to reduce the amount of meat flowing out of the molding cavity and improve the yield, while suppressing the inflow of meat between the knockout pin and the pin hole, and further, the finished molded product can be satisfactorily released. It is to provide a forging method that can be done.

According to one embodiment of the present invention, the forging method is a forging method in which a work is forged by using a plurality of dies including a first forming die, a second forming die, and a finish forming die. Each has an upper mold and a lower mold that form a molding cavity between each other according to the shape of the molded product when the mold is closed in the mold closing direction, and each of the upper mold and the lower mold has. A first flat surface extending from the outer edge of the molding cavity along a direction orthogonal to the mold closing direction, and a direction inclined with respect to the first flat surface from the outer edge of the first flat surface. It has an extending inclined surface and a second flat surface extending outside the outer edge of the inclined surface along a direction orthogonal to the mold closing direction, and each of the molds is closed. A first gap is formed between the first flat surfaces of the upper mold and the lower mold, and a second gap is formed between the second flat surfaces. An outflow suppressing portion is formed between the inclined surfaces of the upper mold and the lower mold that are closed, and the work is first molded in the molding cavity of the first molding mold to form a first molded product. In addition, the first inflow step of inflowing the meat of the first inflow amount from the molding cavity into the first gap of the first molding die and the first molded product in the molding cavity of the second molding die. The second inflow step of making the meat of the second inflow amount reach the outflow suppressing portion of the second molding die and the finish molding of the second molded product are performed. A third inflow step in which the meat is flown into the second gap of the finish molding die so as to have a set thickness, and the finish molding die is formed by finish molding in the molding cavity of the mold. It has a mold release step of bringing a knockout pin protruding from the second flat surface into contact with the meat to release the finished molded product, and the first inflow amount is the second inflow step. The amount of the second inflow is such that the meat can reach the outflow suppressing portion, and the second inflow is the meat that flows out into the second gap in the third inflow step. The set thickness is an amount that can be set, and the set thickness is a forging method in which the meat that abuts on the knockout pin in the mold release step is thick enough to withstand the contact with the knockout pin. Is provided.

According to this forging method, as described above, since the outflow suppressing portion is provided at least in the second molding die, the meat flowing into the first gap is made to collide with the inclined surface to cause the meat from the forming cavity to collide with the inclined surface. Outflow can be temporarily regulated. This makes it possible to satisfactorily fill the forming cavity with the work to improve the formability, reduce the amount of meat flowing out of the forming cavity, and improve the yield.

Further, a knockout pin is provided so as to be able to project from the second flat surface of the finish molding die. Since the second flat surface is located farther from the molding cavity than the first flat surface, the pressing force applied to the meat on the second flat surface is smaller than the pressing force applied to the meat on the first flat surface. Even if it is knocked out, it is possible. Further, since the meat is cooled while moving from the first flat surface side to the second flat surface side, the meat is solidified on the second flat surface side as compared with the first flat surface side. ..

Therefore, as described above, by providing the knockout pin and the pin hole on the second flat surface, it is possible to suppress the inflow of meat between the knockout pin and the pin hole. Therefore, it becomes possible to continuously perform finish molding in the finish molding mold. Further, in the finish molding die, it is possible to prevent product defects due to the inflowing meat and wear of the pin hole.

Further, as described above, the first inflow amount in the first molding and the second molding, which is the pre-process of the finish molding, so that the meat (burr portion) of the set thickness is formed in the second gap by the finish molding. And the second inflow amount is adjusted respectively. As a result, even if the knockout pin is provided so as to be able to protrude from the second flat surface of the finish molding die as described above, the knockout pin and the meat (burr portion) in the second gap are brought into contact with each other. The finished molded product can be satisfactorily released from the mold.

From the above, according to this forging method, it is possible to suppress the inflow of meat between the knockout pin and the pin hole while reducing the amount of meat flowing out from the molding cavity and improving the yield, and the finished molded product is good. It is possible to release the mold.

In the above forging method, in the second inflow step, the distance between the first flat surfaces of the second molding die is made smaller than the distance between the first flat surfaces of the first molding die. Therefore, it is preferable that the meat reaches the outflow suppressing portion of the second molding die. In this case, the meat that has flowed between the first flat surfaces (first gap) in the first inflow step can be pushed out from the first gap toward the outflow suppressing portion in the second inflow step. As a result, the thickness of the meat flowing into the second gap can be easily set to the set thickness in the third inflow step, so that the finished molded product can be satisfactorily released in the mold release step.

In the above forging method, in the first inflow step, crushing may be performed in the molding cavity, and in the second inflow step, rough molding may be performed in the molding cavity. In this case, further rough forming may be performed between the second inflow step and the third inflow step.

In the above manufacturing method, in the first inflow step, the first rough molding may be performed in the molding cavity, and in the second inflow step, the second rough molding may be performed in the molding cavity. In this case, crushing may be performed before the first inflow step.

In the above forging method, in the first inflow step, it is preferable that the distance between the first flat surfaces is set so that the thickness of the meat in the first gap becomes uniform. In this way, in the first inflow step, after equalizing the thickness of the meat in the first gap, the second inflow step and the third inflow step are performed, so that the thickness of the meat in the second gap is also substantially uniform. Can be. As a result, in the mold release step, a plurality of knockout pins can be brought into contact with the meat in the second gap at the same protrusion height. As a result, it becomes possible to release the finished molded product in a more stable state without tilting it.

In the above forging method, at least in the second molding die, it is preferable that the volume of the outflow suppressing portion is smaller than the volume of the first gap. In this case, it is possible to increase the filling pressure of the work with respect to the forming cavity to improve the formability, and to reduce the amount of meat flowing out from the forming cavity to improve the yield.

In the above forging method, the distance between the outer edges of the inclined surface formed between the upper mold and the lower mold of the finish molding mold closed at least in the third inflow step is the second. It is preferably larger than the distance between the inclined surfaces formed between the upper mold and the lower mold of the second molding mold closed in the inflow step.

In this case, in the above forging method, it is preferable that the distance between the outer edge portions is a length equal to or larger than a predetermined wall thickness that can withstand the contact with the knockout pin.

This is the manufacturing flow of a crankshaft, which is a forged product. It is sectional drawing of the crushing mold for demonstrating the 1st inflow process of the forging method which concerns on 1st Embodiment of this invention. It is sectional drawing of the 1st rough molding die for demonstrating the 2nd inflow process which concerns on 1st Embodiment. It is sectional drawing of the 2nd rough molding mold which concerns on 1st Embodiment. It is sectional drawing of the finish molding die for demonstrating the 3rd inflow process and the mold release process which concerns on 1st Embodiment. It is a top view of the lower die of the finish molding die of FIG. It is sectional drawing of the crushing mold used in the forging method which concerns on 2nd Embodiment of this invention. It is sectional drawing of the 1st rough molding die for demonstrating the 1st inflow process which concerns on 2nd Embodiment. It is sectional drawing of the 2nd rough molding type for demonstrating the 2nd inflow process which concerns on 2nd Embodiment. It is sectional drawing of the finish molding die for demonstrating the 3rd inflow process and the mold release process which concerns on 2nd Embodiment.

A suitable embodiment of the forging method according to the present invention will be described in detail with reference to the accompanying drawings.

In the following, an example of the forging method according to the present embodiment applied to obtain a crankshaft will be described, but the present invention is not particularly limited to this, and is applied to obtain various forged products. Is possible.

The forging method according to the first embodiment will be described with reference to FIGS. 1 to 6. As shown in FIGS. 1 and 2, in this forging method, first, a so-called crushing molding (first forming) is performed on a rod-shaped work 10 using a crushing forming die (first forming die) 14. The crushed molded product (first molded product) 16 is used.

Specifically, as shown in FIG. 2, the crushing mold 14 has an upper mold 20 and a lower mold 22, and these upper mold 20 and the lower mold 22 are between each other when the mold is closed. A molding cavity 24 corresponding to the shape of the crushed molded product 16 is formed. The forging method according to the first embodiment is performed using the components on the left side of the paper surface of FIG. 2 with respect to the forming cavity 24 of the crushing forming die 14. Therefore, the description of the crushed mold 14 according to the first embodiment is basically for each component arranged on the left side of the paper surface of FIG. 2. Each of the upper die 20 and the lower die 22 has a first flat surface 26a, 26b, an inclined surface 28a, 28b, and a second flat surface 30a, 30b.

The first flat surfaces 26a and 26b extend from the outer edge portion of the molding cavity 24 along a direction orthogonal to the mold closing direction (arrow direction in FIG. 2), respectively. Further, when the upper mold 20 and the lower mold 22 are closed, the first gap 32 is formed between the first flat surfaces 26a and 26b.

The inclined surfaces 28a and 28b extend from the outer edges of the first flat surfaces 26a and 26b in the direction in which they are inclined with respect to the first flat surfaces 26a and 26b, respectively. Further, when the upper mold 20 and the lower mold 22 are closed, the outflow suppressing portion 34 is formed between the inclined surfaces 28a and 28b.

In the present embodiment, an example will be described in which the inclined surfaces 28a and 28b are inclined so that the outer edge portion side is arranged downward (X side in the arrow direction in FIG. 2) with respect to the first flat surface 26a and 26b side. , The outer edge portion side may be inclined so as to be arranged above (Y side in the arrow direction in FIG. 2) with respect to the first flat surface 26a, 26b side. Further, the inclined surface 28b of the lower die 22 extends from the upper end to the lower end so as to be curved in a direction away from the inclined surface 28a of the upper die 20.

The second flat surfaces 30a and 30b are provided outside the outer edges of the inclined surfaces 28a and 28b, and extend along a direction orthogonal to the mold closing direction, respectively. In the present embodiment, the second flat surface 30a of the upper die 20 is provided so as to extend from the outer edge portion of the inclined surface 28a, and the second flat surface 30b of the lower die 22 is further provided from the outer edge portion of the inclined surface 28b. It is provided so as to extend from the lower end portion of the descending surface 36 extending downward. The distance between the second flat surfaces 30a and 30b increases by the length of the descending surface 36. A second gap 38 is formed between the second flat surfaces 30a and 30b when the upper mold 20 and the lower mold 22 are closed.

The work 10 is crushed and molded into the crushed molded product 16 in the forming cavity 24 of the crushing forming die 14, and the meat 16a having a first inflow amount described later is made to flow into the first gap 32 from the forming cavity 24. Perform the first inflow step. The meat 16a that has flowed into the first gap 32 in this way becomes the burr portion of the crushed molded product 16.

Next, as shown in FIGS. 1 and 3, so-called first rough molding (second molding) is performed on the crushed molded product 16 using the first rough molding die (second molding die) 40. The first rough molded product (second molded product) 42. As for the first rough forming die 40, as in the case of the above-mentioned crushing forming die 14, basically, the components on the left side of the paper surface of FIG. 3 will be described.

Specifically, as shown in FIG. 3, the first rough forming die 40 has an upper die 44 and a lower die 46, and these upper die 44 and the lower die 46 are mutually when the die is closed. A molding cavity 48 corresponding to the shape of the first rough molded product 42 is formed between the two. Further, each of the upper die 44 and the lower die 46 has first flat surfaces 50a and 50b, inclined surfaces 52a and 52b, and second flat surfaces 54a and 54b, respectively.

The first flat surfaces 50a and 50b extend from the outer edge portion of the molding cavity 48 along a direction orthogonal to the mold closing direction, respectively. Further, when the upper mold 44 and the lower mold 46 are closed, the first gap 56 is formed between the first flat surfaces 50a and 50b. The distance L1 between the first flat surfaces 50a and 50b when the upper mold 44 and the lower mold 46 are closed is the first flat surface when the upper mold 20 and the lower mold 22 of the crushing mold 14 are closed. The distances L2 of the surfaces 26a and 26b are set to be smaller than the distance L2.

The inclined surfaces 52a and 52b extend from the outer edges of the first flat surfaces 50a and 50b in a direction in which they are inclined with respect to the first flat surfaces 50a and 50b, respectively. The inclined surfaces 52a and 52b are also inclined in basically the same direction as the inclined surfaces 28a and 28b of the crushing mold 14, but a substantially flat flat portion 53a is provided on the outer edge portion side of the inclined surface 52a. .. Further, when the upper mold 44 and the lower mold 46 are closed, the outflow suppressing portion 58 is formed between the inclined surfaces 52a and 52b. The volume of the outflow suppressing portion 58 is smaller than the volume of the first gap 56.

The second flat surfaces 54a and 54b are provided outside the outer edges of the inclined surfaces 52a and 52b, and extend along a direction orthogonal to the mold closing direction, respectively. In the present embodiment, the second flat surface 54a of the upper die 44 is provided so as to extend from the upper end portion of the ascending surface 60 extending further upward from the outer edge portion of the inclined surface 52a. Further, the second flat surface 54b of the lower mold 46 is provided so as to extend from the lower end portion of the descending surface 62 extending further downward from the outer edge portion of the inclined surface 52b. The distance between the second flat surfaces 54a and 54b increases by the length of the ascending surface 60 and the descending surface 62. A second gap 64 is formed between the second flat surfaces 54a and 54b when the upper mold 44 and the lower mold 46 are closed. The distance L3 between the second flat surfaces 54a and 54b when the upper mold 44 and the lower mold 46 are closed is larger than the distance (shortest distance) L4 between the inclined surfaces 52a and 52b.

In the molding cavity 48 of the first rough molding die 40, the crushed molded product 16 is first rough molded (second molding) to obtain the first rough molded product 42, and the meat 42a having a second inflow amount, which will be described later. Is performed in the second inflow step of reaching the outflow control unit 58. As a result, the meat 42a that reaches the outflow suppressing portion 58 through the first gap 56 becomes the burr portion of the first rough molded product 42. Therefore, the protruding dimension of the burr portion (meat 42a) of the first rough molded product 42 is larger than the protruding dimension of the burr portion (flesh 16a) of the crushed molded product 16.

Further, in the first rough forming die 40, as described above, the volume of the outflow suppressing portion 58 is set to be smaller than the volume of the first gap 56, so that the meat 42a flowing out from the first gap 56 flows out. Is temporarily suppressed between the inclined surfaces 52a and 52b (outflow suppressing portion 58). This makes it possible to increase the filling inside the molding cavity 48.

Next, as shown in FIGS. 1 and 4, the first rough-molded product 42 is subjected to so-called second rough-molding using the second rough-molded mold 66 to obtain the second rough-molded product 68. As for the second rough forming die 66, as in the case of the above-mentioned crushing forming die 14, basically, the components on the left side of the paper surface of FIG. 4 will be described.

Specifically, as shown in FIG. 4, the second rough forming mold 66 has an upper mold 70 and a lower mold 72, and these upper mold 70 and the lower mold 72 each other when the mold is closed. A molding cavity 74 corresponding to the shape of the second rough molded product 68 is formed between the two. Further, each of the upper die 70 and the lower die 72 has first flat surfaces 76a and 76b, inclined surfaces 78a and 78b, and second flat surfaces 80a and 80b, respectively.

The first flat surfaces 76a and 76b extend from the outer edge portion of the molding cavity 74 along a direction orthogonal to the mold closing direction, respectively. Further, when the upper mold 70 and the lower mold 72 are closed, the first gap 82 is formed between the first flat surfaces 76a and 76b. The distance L5 of the first flat surfaces 76a and 76b when the upper mold 70 and the lower mold 72 are closed is smaller than the above-mentioned distance L1 and distance L2. Therefore, the volume of the first gap 82 of the second rough forming die 66 is smaller than the volume of the first gap 56 of the first rough forming die 40 and the volume of the first gap 32 of the crushed forming die 14.

The inclined surfaces 78a and 78b extend from the outer edges of the first flat surfaces 76a and 76b in the direction in which they are inclined with respect to the first flat surfaces 76a and 76b, respectively. The inclined surface 78a of the upper die 70 is inclined downward in the same manner as the first rough forming die 40. Further, a substantially flat flat portion 77a is provided on the outer edge portion 78ae side of the inclined surface 78a. On the outer edge portion 78be side of the inclined surface 78b of the lower die 72, a curved portion 77b curved in a direction away from the inclined surface 78a of the upper die 70 is provided. By providing the flat portion 77a and the curved portion 77b in this way, the distance L6 between the outer edge portions 78ae and 78be of the inclined surfaces 78a and 78b when the upper mold 70 and the lower mold 72 are closed is the inclined surface 78a. , 78b is larger than the distance L7.

The second flat surfaces 80a and 80b are provided outside the outer edge portions 78ae and 78be of the inclined surfaces 78a and 78b, and extend along a direction orthogonal to the mold closing direction, respectively. The second flat surface 80a of the upper die 70 is continuously provided on the ascending surface 79 rising upward from the flat portion 77a provided on the outer edge portion 78ae side of the inclined surface 78a. The second flat surface 80b of the lower mold 72 is provided so as to extend from the lower end portion of the descending surface 84 extending further downward from the curved portion 77b provided on the outer edge portion 78be side of the inclined surface 78b. A second gap 86 is formed between the second flat surfaces 80a and 80b when the upper mold 70 and the lower mold 72 are closed. The distance L8 between the second flat surfaces 80a and 80b when the upper mold 70 and the lower mold 72 are closed is larger than the distance L7 between the inclined surfaces 78a and 78b.

The first rough-molded product 42 is second-roughly molded in the molding cavity 74 of the second rough-molded mold 66 to obtain a second rough-molded product 68. At this time, the meat 68a flowing out of the molding cavity 74 reaches the second gap 86 via the first gap 82. At this time, as described above, the volume of the first gap 82 in the second rough forming die 66 is smaller than the volume of the first gap 56 of the first rough forming die 40 and the volume of the first gap 32 of the crushed forming die 14. .. Therefore, the meat 68a flowing out from the molding cavity 74 flows out into the second gap 86 together with the meat in the first gap 82.

As described above, the distance L8 between the second flat surfaces 80a and 80b forming the second gap 86 is larger than the distance L7 between the inclined surfaces 78a and 78b. Since the distance L6 between the outer edge portions 78ae and 78be of the inclined surfaces 78a and 78b is larger than the distance L7 between the inclined surfaces 78a and 78b, the volume between the inclined surfaces 78a and 78b is on the first flat surface 76a and 76b side. It is larger on the outer edge portions 78ae and 78be side than the outer edge portion. From these, the meat 68a is released from the pressured state by passing through the inclined surfaces 78a and 78b and flowing out to the second gap 86 through the space between the outer edge portions 78ae and 78be. As a result, the thick portion 69 is formed on the meat 68a. This meat 68a becomes a burr portion of the second rough molded product 68. Therefore, the protruding dimension of the burr portion (meat 68a) of the second rough molded product 68 is larger than the protruding dimension of the burr portion (flesh 42a) of the first rough molded product 42.

Next, as shown in FIGS. 1 and 5, so-called finish molding is performed on the second rough molded product 68 using the finish molding die 90, and a crankshaft with burrs having substantially the final shape and dimensions (finish molding). Product) 92. As for the finish molding die 90, basically, the components on the left side of the paper surface of FIG. 5 will be described in the same manner as in the above-mentioned crushing molding die 14.

Specifically, as shown in FIG. 5, the finish molding die 90 has an upper die 94 and a lower die 96, and these upper die 94 and the lower die 96 are between each other when the die is closed. A molded cavity 98 corresponding to the shape of the crankshaft 92 with burrs is formed in the burrs. Further, each of the upper mold 94 and the lower mold 96 has first flat surfaces 100a and 100b, inclined surfaces 102a and 102b, and second flat surfaces 104a and 104b, respectively.

The first flat surfaces 100a and 100b extend from the outer edge portion of the molding cavity 98 along a direction orthogonal to the mold closing direction, respectively. Further, when the upper mold 94 and the lower mold 96 are closed, the first gap 106 is formed between the first flat surfaces 100a and 100b.

The inclined surfaces 102a and 102b extend from the outer edges of the first flat surfaces 100a and 100b in a direction in which they are inclined with respect to the first flat surfaces 100a and 100b, respectively. In the present embodiment, the inclined surface 102a of the upper die 94 is inclined toward the molding cavity 98 side so that the outer edge portion side is arranged above the first flat surface 100a side. On the other hand, the inclined surface 102b of the lower mold 96 is inclined toward the molding cavity 98 side so that the outer edge portion side is arranged below the first flat surface 100b side. The distance L9 between the outer edge portions 102ae and 102be of the inclined surfaces 102a and 102b when the upper mold 94 and the lower mold 96 are closed is the distance L4 and the second of the inclined surfaces 52a and 52b of the first rough forming mold 40. 2 The distance L7 between the inclined surfaces 78a and 78b of the rough forming die 66 is larger than any of them.

The second flat surfaces 104a and 104b are provided outside the outer edge portions 102ae and 102be of the inclined surfaces 102a and 102b, and extend along a direction orthogonal to the mold closing direction, respectively. In the present embodiment, the second flat surface 104a of the upper die 94 is provided so as to extend from the upper end portion of the ascending surface 108 extending further upward from the outer edge portion 102ae of the inclined surface 102a. Further, the second flat surface 104b of the lower mold 96 is provided so as to extend from the lower end portion of the descending surface 110 extending further downward from the outer edge portion 102be of the inclined surface 102b. A second gap 112 is formed between the second flat surfaces 104a and 104b when the upper mold 94 and the lower mold 96 are closed.

Further, as shown in FIG. 6, the lower mold 96 is provided with a plurality of knockout pins 114 so as to be projectable on the second flat surface 104b.

In the molding cavity 98 of the finish molding die 90, the second rough molded product 68 is finished molded to form a crankshaft 92 with burrs, and a meat 92a is formed in the second gap 112 so as to have a set thickness described later. The third inflow step of inflowing is performed. The meat 92a that has flowed into the second gap 112 in this way becomes the burr portion of the crankshaft 92 with burrs. That is, the burr portion made of the meat 92a having the set thickness is arranged in the second gap 112. The meat 92a thus arranged in the second gap 112 has a wall thickness portion 69, and the thickness of the meat 92a is such that it can withstand the pressing of the knockout pin 114.

Next, after opening the upper mold 94 and the lower mold 96, a mold release step of abutting the knockout pin 114 protruding from the second flat surface 104b of the finish molding mold 90 to release the crankshaft 92 with burrs. I do. After that, the burr portion (flesh 92a) on the peripheral edge of the crankshaft 92 with burrs is separated by deburring (trimming). This gives the crankshaft 116.

From the above, in the forging method according to the present embodiment, as described above, since the inclined surfaces 52a and 52b are provided on the first rough forming die (second forming die) 40, the forming cavity 48 becomes the first gap 56. The inflowing meat 42a collides with the inclined surface 52a. Further, the volume of the outflow suppressing portion 58 formed between the inclined surfaces 52a and 52b is set smaller than the volume of the first gap 56. With these, the outflow of the meat 42a from the forming cavity 48 can be temporarily restricted. As a result, the first rough molded product 42 is satisfactorily filled in the molding cavity 48 to improve the moldability, the amount of the meat 42a flowing out from the molding cavity 48 is reduced, and the yield is improved. It will be possible.

Further, as described above, the knockout pin 114 is provided so as to be able to project from the second flat surface 104b of the finish molding die 90. Since the second flat surface 104b is arranged farther from the molding cavity 98 than the first flat surface 100b, the pressing force applied to the meat 92a on the second flat surface 104b is applied to the meat 92a on the first flat surface 100b. It can be smaller than the pressing force applied. Further, since the meat 92a is cooled while moving from the first flat surface 100b side to the second flat surface 104b side, the meat 92a is cooled on the second flat surface 104b side as compared with the first flat surface 100b side. Is progressing.

Therefore, as described above, by providing the knockout pin 114 and the pin hole (not shown) on the second flat surface 104b, it is possible to suppress the inflow of the meat 92a between the knockout pin 114 and the pin hole. Therefore, it becomes possible to continuously perform finish molding in the finish molding mold 90. In addition, it is possible to prevent product defects and pin hole mold wear due to the inflowing meat 92a in the finish molding die 90.

Further, as described above, by adjusting the first inflow amount and the second inflow amount in the crushing molding and the first rough forming, respectively, the meat 92a (burr portion) having a set thickness is formed in the second gap 112 in the finish molding. Can be formed. That is, the first inflow amount is an amount that enables the meat 42a of the second inflow amount to reach the outflow suppressing portion 58 in the second inflow step. The second inflow amount is an amount that enables the meat 92a flowing out into the second gap 112 to have a set thickness in the third inflow step. The set thickness is a thickness at which the meat 92a that comes into contact with the knockout pin 114 in the mold release step can withstand the contact with the knockout pin 114.

Therefore, as described above, even if the knockout pin 114 is provided on the second flat surface 104b of the finish molding die 90, the knockout pin 114 and the meat 92a (burr portion) in the second gap 112 are brought into contact with each other. Therefore, the crankshaft 92 with burrs can be satisfactorily released. As a result, according to this forging method, it is possible to suppress the inflow of the meat 92a between the knockout pin 114 and the pin hole while improving the yield, and it is possible to satisfactorily release the crankshaft 92 with burrs. It is possible.

Further, as described above, the distance L1 of the first flat surfaces 50a and 50b of the first rough forming die (second forming die) 40 is the distance L1 of the first flat surfaces 26a and 26b of the crushing forming die (first forming die) 14. It is set smaller than the distance L2. As a result, in the first inflow step, the meat 16a can be satisfactorily flowed between the first flat surfaces 26a and 26b (first gap 32), and in the second inflow step, the meat 42a in the first gap 56 can be satisfactorily flowed. Can be pushed toward the outflow control unit 58. That is, the meat 42a can be effectively reached from the first gap 56 to the outflow suppressing portion 58. As a result, the thickness of the meat 92a flowing into the second gap 112 can be easily set to the set thickness in the third inflow step, so that the crankshaft 92 with burrs can be satisfactorily released in the mold release step. become.

In the above embodiment, the second rough forming is performed by using the second rough forming die 66 between the third inflow step and the second inflow step. Therefore, by adjusting the distance L6 between the outer edge portions 78ae and 78be of the inclined surfaces 78a and 78b of the second rough forming die 66, the thickness of the meat 92a flowing into the second gap 112 in the third inflow step can be adjusted. The set thickness can be easily set.

The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof.

For example, in the above-mentioned first embodiment, the crushing molding is performed in the first inflow step and the first rough molding is performed in the second inflow step, but the present invention is not particularly limited to this. For example, as in the forging method according to the second embodiment shown in FIGS. 7 to 10, the first rough forming may be performed in the first inflow step, and the second rough forming may be performed in the second inflow step. 7 to 10 are cross-sectional views of other parts of the mold shown in FIGS. 2 to 5. Further, among the components shown in FIGS. 7 to 10, those having the same or similar functions and effects as those shown in FIGS. 2 to 5 are designated by the same reference numerals and described in detail. Is omitted.

That is, as shown in FIG. 7, the work 10 is crushed and molded in the molding cavity 24 of the crushing mold 14 to obtain a crushed molded product 16. At this stage, the meat 16a does not flow into the first gap 32.

Next, as shown in FIG. 8, the crushed molded product 16 is first rough-molded (first rough-molded) in the molding cavity 48 of the first rough-molding mold (first molding die) 40, and the first rough-molding is performed. In addition to making the product (first molded product) 42, the first inflow step of inflowing the first inflow amount of meat 42a from the molding cavity 48 into the first gap 56 is performed.

Next, as shown in FIG. 9, the first rough-molded product 42 is second-roughly molded (second molded) in the molding cavity 74 of the second rough-molded mold (second molding mold) 66, and the second rough-molded product 42 is formed. A rough molded product (second molded product) 68 is used, and a second inflow step is performed in which the meat 68a of the second inflow amount reaches the outflow suppressing portion 75 formed between the inclined surfaces 78a and 78b.

When the upper mold 70 and the lower mold 72 are closed, an outflow suppressing portion 75 having a volume smaller than that of the first gap 82 is formed between the inclined surfaces 78a and 78b. A substantially flat flat portion 77a is provided on the outer edge portion 78ae side of the inclined surface 78a of the upper die 70 with respect to the outflow suppressing portion 75. A curved portion 77b curved in a direction away from the inclined surface 78a of the upper mold 70 is provided on the outer edge portion 78be side of the inclined surface 78b of the lower mold 72 with respect to the outflow suppressing portion 75.

By providing the flat portion 77a and the curved portion 77b in this way, the distance between the outer edge portions 78ae and 78be of the inclined surfaces 78a and 78b when the upper mold 70 and the lower mold 72 are closed is the inclined surface 78a, It is larger than the distance of 78b. That is, the volume between the outer edge portions 78ae and 78be of the inclined surfaces 78a and 78b is larger than the volume of the outflow suppressing portion 75. In this case, the meat 68a is released from the pressured state by passing through the outflow suppressing portion 75 and flowing out into the second gap 86 through between the outer edges of the inclined surfaces 78a and 78b. As a result, the thick portion 69 is formed on the meat 68a.

Next, as shown in FIG. 10, the second rough-molded product 68 is finished-molded in the molding cavity 98 of the finish-molding mold 90 to form a crankshaft with burrs (finish-molded product) 92, and a thick portion. A third inflow step is performed in which the meat 92a having a set thickness, which will be described later, provided with 69 is allowed to flow into the second gap 112. The meat 92a that has flowed into the second gap 112 in this way becomes the burr portion of the crankshaft 92 with burrs. That is, the burr portion made of the meat 92a having the set thickness is arranged in the second gap 112.

Next, after opening the upper mold 94 and the lower mold 96, a mold release step of abutting the knockout pin 114 protruding from the second flat surface 104b of the finish molding mold 90 to release the crankshaft 92 with burrs. I do.

Even with the forging method according to the second embodiment described above, the same action and effect as the forging method according to the first embodiment described above can be obtained. That is, it is possible to suppress the inflow of the meat 92a between the knockout pin 114 and the pin hole while improving the yield, and it is possible to satisfactorily release the crankshaft 92 with burrs.

In the first embodiment and the second embodiment described above, the meat 92a (burr portion) having the wall thickness portion 69 is formed, but the present invention is not particularly limited thereto. For example, as in the forging method according to the third embodiment, the meat 192a may be formed with a substantially uniform thickness without the wall thickness portion 69.

The forging method according to the third embodiment is performed using the components on the right side of the paper surface of FIG. 2 with respect to the forming cavity 24 of the crushing forming die 14. Therefore, the description of the crushed mold 14 according to the third embodiment is basically for each component arranged on the right side of the paper surface of FIG. 2. Similarly, the description of the first rough forming die (second forming die) 40, the second rough forming die 66, and the finish forming die 90 regarding the third embodiment is basically on the right side of the paper surface of FIGS. 3 to 5. It is for each of the arranged components.

As shown in FIG. 2, each of the upper mold 20 and the lower mold 22 of the crushing mold 14 has first flat surfaces 126a and 126b, inclined surfaces 128a and 128b, and second flat surfaces 130a and 130b, respectively. The first flat surfaces 126a and 126b extend from the outer edge portion of the molding cavity 24 along a direction orthogonal to the mold closing direction (arrow direction in FIG. 2), respectively. Further, when the upper mold 20 and the lower mold 22 are closed, the first gap 132 is formed between the first flat surfaces 126a and 126b.

The inclined surfaces 128a and 128b extend from the outer edges of the first flat surfaces 126a and 126b in the direction in which they are inclined with respect to the first flat surfaces 126a and 126b, respectively. Further, when the upper mold 20 and the lower mold 22 are closed, the outflow suppressing portion 134 is formed between the inclined surfaces 128a and 128b. The inclined surface 128b of the lower mold 22 extends from the upper end to the lower end so as to be curved in a direction away from the inclined surface 128a of the upper mold 20.

The second flat surfaces 130a and 130b are provided outside the outer edges of the inclined surfaces 128a and 128b, and extend along a direction orthogonal to the mold closing direction, respectively. The second flat surface 130a of the upper die 20 is provided so as to extend from the outer edge portion of the inclined surface 128a, and the second flat surface 130b of the lower die 22 extends further downward from the outer edge portion of the inclined surface 128b. It extends from the lower end of the descending surface 136. A second gap 138 is formed between the second flat surfaces 130a and 130b when the upper mold 20 and the lower mold 22 are closed.

In the molding cavity 24 of the crushing molding die 14, the work 10 is crushed and molded to obtain a crushed molded product 16, and the first inflow of meat 116a having a first inflow amount from the molding cavity 24 into the first gap 132. Perform the process. At this time, the distances between the first flat surfaces 126a and 126b are set so that the thickness of the meat 116a in the first gap 132 becomes uniform.

Next, as shown in FIG. 3, the upper mold 44 and the lower mold 46 of the first rough forming mold 40 have the first flat surfaces 150a and 150b, the inclined surfaces 152a and 152b, and the second flat surfaces 154a, respectively. It has 154b and. The first flat surfaces 150a and 150b extend from the outer edge portion of the molding cavity 48 along a direction orthogonal to the mold closing direction, respectively. Further, when the upper mold 44 and the lower mold 46 are closed, the first gap 156 is formed between the first flat surfaces 150a and 150b. The distance between the first flat surfaces 150a and 150b is set to be smaller than the distance between the first flat surfaces 126a and 126b of the crushing mold 14.

The inclined surfaces 152a and 152b extend from the outer edges of the first flat surfaces 150a and 150b in the direction in which they are inclined with respect to the first flat surfaces 150a and 150b, respectively. The inclined surfaces 152a and 152b are also inclined in basically the same direction as the inclined surfaces 128a and 128b of the crushing mold 14, but a substantially flat flat portion is provided on the outer edge portion side of the inclined surfaces 152a and 152b. There is. Further, when the upper mold 44 and the lower mold 46 are closed, the outflow suppressing portion 158 is formed between the inclined surfaces 152a and 152b. The volume of the outflow suppressing portion 158 is smaller than the volume of the first gap 156.

The second flat surfaces 154a and 154b are provided outside the outer edges of the inclined surfaces 152a and 152b, and extend along a direction orthogonal to the mold closing direction, respectively. The second flat surface 154a of the upper die 44 is provided so as to extend from the upper end portion of the ascending surface 160 extending further upward from the outer edge portion of the inclined surface 152a. Further, the second flat surface 154b of the lower die 46 is provided so as to extend from the lower end portion of the descending surface 162 extending further downward from the outer edge portion of the inclined surface 152b. A second gap 164 is formed between the second flat surfaces 154a and 154b when the upper mold 44 and the lower mold 46 are closed.

In the molding cavity 48 of the first rough molding die 40, the crushed molded product 16 is first rough molded (second molding) to obtain the first rough molded product 42, and the meat 142a having a second inflow amount is suppressed from flowing out. The second inflow step of reaching the portion 158 is performed. As a result, the meat 142a that reaches the outflow suppressing portion 158 through the first gap 156 becomes the burr portion of the first rough molded product 42.

Next, as shown in FIG. 4, each of the upper die 70 and the lower die 72 of the second rough forming die 66 has a first flat surface 176a, 176b, an inclined surface 178a, 178b, and a second flat surface 180a, respectively. It has 180b. The first flat surfaces 176a and 176b extend from the outer edge of the molding cavity 74 along a direction orthogonal to the mold closing direction. Further, when the upper mold 70 and the lower mold 72 are closed, the first gap 182 is formed between the first flat surfaces 176a and 176b.

The inclined surfaces 178a and 178b extend from the outer edge portion of the first flat surface 176a and 176b in the direction of inclination with respect to the first flat surface 176a and 176b, respectively. Further, a substantially flat flat portion is provided at the lower end of the inclined surface 178b of the lower mold 72. The second flat surfaces 180a and 180b are provided outside the outer edges of the inclined surfaces 178a and 178b, and extend along a direction orthogonal to the mold closing direction, respectively. The second flat surface 180a is provided so as to extend from the outer edge portion of the inclined surface 178a, and the second flat surface 180b extends from the lower end portion of the descending surface 184 extending further downward from the outer edge portion of the inclined surface 178b. It is provided to be there. A second gap 186 is formed between the second flat surfaces 180a and 180b when the upper mold 70 and the lower mold 72 are closed.

The first rough-molded product 42 is second-roughly molded in the molding cavity 74 of the second rough-molded mold 66 to obtain the second rough-molded product 68. At this time, the meat 168a flowing out of the molding cavity 74 reaches the second gap 186 via the first gap 182. This meat 168a serves as a burr portion of the second rough molded product 68. The forging method according to the third embodiment can be suitably performed when the capacity of the meat 116a (FIG. 2) of the first inflow amount is relatively large, and the outflow suppressing portion in the first rough forming mold 40 of FIG. 3 can be performed. The distance between the inclined surfaces 152a and 152b of 158 is made equal to the wall thickness that can withstand the contact of the knockout pin 114 in FIG. Therefore, in the second rough forming die 66 of FIG. 4, the meat 168a has a thickness that can withstand the contact of the knockout pin 114.

Next, as shown in FIG. 5, each of the upper die 94 and the lower die 96 of the finish molding die 90 has a first flat surface 1100a and 1100b, an inclined surface 1102a and 1102b, and a second flat surface 1104a and 1104b, respectively. Has. The first flat surfaces 1100a and 1100b extend from the outer edge portion of the molding cavity 98 along a direction orthogonal to the mold closing direction, respectively. Further, when the upper mold 94 and the lower mold 96 are closed, the first gap 1106 is formed between the first flat surfaces 1100a and 1100b.

The inclined surfaces 1102a and 1102b extend from the outer edge portions of the first flat surfaces 1100a and 1100b in the direction in which they are inclined with respect to the first flat surfaces 1100a and 1100b, respectively. The inclined surface 1102a of the upper die 94 is inclined toward the molding cavity 98 side so that the outer edge portion side is arranged above the first flat surface 1100a side. On the other hand, the inclined surface 1102b of the lower mold 96 is inclined toward the molding cavity 98 side so that the outer edge portion side is arranged below the first flat surface 1100b side.

The second flat surfaces 1104a and 1104b are provided outside the outer edges of the inclined surfaces 1102a and 1102b, and extend along a direction orthogonal to the mold closing direction, respectively. The second flat surface 1104a of the upper die 94 is provided so as to extend from the upper end portion of the ascending surface 1108 extending further upward from the outer edge portion of the inclined surface 1102a. Further, the second flat surface 1104b of the lower mold 96 is provided so as to extend from the lower end portion of the descending surface 1110 extending further downward from the outer edge portion of the inclined surface 1102b. A second gap 1112 is formed when the upper mold 94 and the lower mold 96 are closed between the second flat surfaces 1104a and 1104b.

In the molding cavity 98 of the finish molding die 90, the second rough molded product 68 is finished molded to form a crankshaft 92 with burrs, and the meat 192a is flowed into the second gap 1112 so as to have a set thickness. 3 Perform the inflow process. The meat 192a that has flowed into the second gap 1112 in this way becomes the burr portion of the crankshaft 92 with burrs. That is, the burr portion made of the meat 192a having the set thickness is arranged in the second gap 1112. In this way, the thickness of the meat 192a arranged in the second gap 1112 is uniform. This is because, as described above, in the first inflow step, the thickness of the meat 116a in the first gap 132 is made uniform.

Next, after opening the upper mold 94 and the lower mold 96, a mold release step of abutting the knockout pin 114 protruding from the second flat surface 1104b of the finish molding mold 90 to release the crankshaft 92 with burrs. And so on.

In the forging method according to the third embodiment, the same action and effect as the forging method according to the first embodiment can be obtained, and as described above, the thickness of the meat 192a in the second gap 1112 is uniform. Therefore, the plurality of knockout pins 114 can be brought into contact with the meat 192a at the same protrusion height. As a result, it becomes possible to release the mold in a more stable state without tilting the crankshaft 92 with burrs.

Claims (8)

A forging method in which a work (10) is forged using a plurality of dies including a first forming die (14, 40), a second forming die (40, 66), and a finishing forming die (90). There,
When each of the molds is closed in the mold closing direction, molding cavities (24, 48, 74, 98) corresponding to the shape of the molded product (16, 42, 68, 92) are formed between the molds. It has an upper mold (20, 44, 70, 94) and a lower mold (22, 46, 72, 96) to be formed.
Each of the upper mold and the lower mold has a first flat surface (26a, 26b, 50a, 50b, 76a, 76b, 76b, 100a) extending from the outer edge of the molding cavity along a direction orthogonal to the mold closing direction. , 100b, 126a, 126b, 150a, 150b, 176a, 176b, 1100a, 1100b) and an inclined surface (28a) extending in a direction inclined with respect to the first flat surface from the outer edge portion of the first flat surface. , 28b, 52a, 52b, 78a, 78b, 102a, 102b, 128a, 128b, 152a, 152b, 178a, 178b, 1102a, 1102b), and the direction outside the outer edge of the inclined surface is orthogonal to the mold closing direction. It has a second flat surface (30a, 30b, 54a, 54b, 80a, 80b, 104a, 104b, 130a, 130b, 154a, 154b, 180a, 180b, 1104a, 1104b) extending along the surface.
Each of the molds forms a first gap (32, 56, 82, 106, 132, 156, 182, 1106) between the first flat surfaces of the upper and lower molds that are closed. At the same time, a second gap (38, 64, 86, 112, 138, 164, 186, 1112) is formed between the second flat surfaces, and at least the second molding die is formed on the closed die. Outflow control portions (34, 58, 75, 134, 158) are formed between the inclined surfaces of the mold and the lower mold.
The work is first molded in the molding cavity of the first molding die to obtain a first molded product (16, 42), and in the first gap of the first molding die, the first from the molding cavity. The first inflow step of inflowing the inflow amount of meat (16a, 116a, 42a, 142a) and
The first molded product is second-molded in the molding cavity of the second molding mold to obtain a second molded product (42, 68), and the meat (42a, 68a, 142a, 168a) having a second inflow amount is obtained. ) To the second inflow control portion of the second molding die, and the second inflow step.
The second molded product is finished-molded in the molding cavity of the finish-molding mold to obtain a finish-molded product (92), and the meat (92a) has a set thickness in the second gap of the finish-molding mold. , 192a) and the third inflow step,
A mold release step in which a knockout pin (114) protruding from the second flat surface of the finish molding mold is brought into contact with the meat to release the finish molding product.
Have,
The first inflow amount is an amount that enables the meat of the second inflow amount to reach the outflow suppressing portion in the second inflow step, and the second inflow amount is the third inflow amount. In the step, the amount of the meat flowing out into the second gap can be set to the set thickness, and the set thickness is such that the meat that comes into contact with the knockout pin in the forging step is formed. A forging method having a thickness that can withstand contact with the knockout pin. In the forging method according to claim 1,
In the second inflow step, the second molding is performed by reducing the distance between the first flat surfaces of the second molding die to be smaller than the distance between the first flat surfaces of the first molding die. A forging method in which the meat reaches the outflow control portion of the mold. In the forging method according to claim 1 or 2.
In the first inflow step, crush molding is performed in the molding cavity, and the molding is performed.
In the second inflow step, a forging method in which rough forming is performed in the forming cavity. In the forging method according to claim 1 or 2.
In the first inflow step, the first rough molding is performed in the molding cavity, and the molding is performed.
In the second inflow step, a forging method in which a second rough forming is performed in the forming cavity. In the forging method according to any one of claims 1 to 4,
In the first inflow step, a forging method in which the distance between the first flat surfaces is set so that the thickness of the meat in the first gap becomes uniform. In the forging method according to any one of claims 1 to 5,
A forging method in which at least in the second molding die, the volume of the outflow suppressing portion is smaller than the volume of the first gap. In the forging method according to any one of claims 1 to 6,
At least the distance (L9) between the outer edges of the inclined surface formed between the upper mold and the lower mold of the finish molding mold closed in the third inflow step is the distance (L9) between the upper molds and the lower mold. A forging method that is larger than the distance (L4, L7) between the inclined surfaces formed between the upper mold and the lower mold that are closed in the second molding mold. In the forging method according to claim 7,
A forging method in which the distance between the outer edge portions is a length equal to or larger than a predetermined wall thickness capable of withstanding contact with the knockout pin.

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