Method for manufacturing molds and forgings

Abstract

The present invention provides a mold and forging method that can be made smaller than conventional methods. [Solution] A die 20 used for closed forging by warm forging or hot forging comprises a lower die 30 and an upper die 40 fixed to a forging machine 10, wherein the upper die 40 comprises a fixed part 50 fixed to the forging machine 10, a movable part 60 that is movable vertically relative to the fixed part 50 when the fixed part 50 is fixed to the forging machine 10 and closes the area between the lower die 30 and the upper die 40 by contacting the lower die 30, and a spring 42 that biases the movable part 60 toward the lower die 30 relative to the fixed part 50 when the fixed part 50 is fixed to the forging machine 10.

Description

Technical Field

[0001] The present invention relates to a mold used for closed forging by warm forging or hot forging and a method for manufacturing a forged product.

Background Art

[0002] Conventionally, as a processing method by warm forging or hot forging, while extruding excess material as burrs from the gap between the lower die and the upper die of the mold, a method of molding the material between the lower die and the upper die (hereinafter referred to as "burr extrusion forging"), and a closed forging which is a method of molding the material in this region with the region between the lower die and the upper die of the mold closed are known.

[0003] In burr extrusion forging, when the amount of material charged between the lower die and the upper die of the mold is reduced, the impact received by the lower die and the upper die during molding increases, so the life of the mold is significantly reduced. Therefore, it is difficult to reduce the amount of material charged between the lower die and the upper die of the mold in burr extrusion forging.

[0004] Also, in burr extrusion forging, when the forging load is reduced, the amount of material pushed in by the lower die and the upper die is reduced, so defects may occur in the processed product molded by forging, that is, the forged product, such as unfilled parts in the forged product or entanglement in the forged product. Therefore, it is difficult to reduce the forging load in burr extrusion forging.

[0005] On the other hand, since closed forging is a processing method capable of suppressing the generation of burrs, the amount of material charged between the lower die and the upper die of the mold can be reduced compared to burr extrusion forging. Also, it is known that closed forging can reduce the forging load compared to burr extrusion forging.

[0006] Conventionally, a die apparatus for achieving closed-hole forging is known to include a lower die attached to the bolster side of a forging machine, an upper die attached to the ram side of the forging machine that closes the area between the upper die and the lower die, a pressurizing means that pressurizes the lower die from below by hydraulic pressure, and an upper counter punch inserted into the upper die (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2000-237835 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, conventional mold devices have a pressurizing mechanism that uses hydraulics to pressurize the lower mold from below, which presents the problem of being large in size.

[0009] Therefore, the present invention aims to provide a mold and a forging method that can be made smaller than conventional molds. [Means for solving the problem]

[0010] The present invention relates to a die used for closed forging by warm forging or hot forging, comprising a lower die and an upper die fixed to a forging machine, wherein at least one of the upper die and the lower die includes a fixed portion fixed to the forging machine, a movable portion that is movable vertically relative to the fixed portion when the fixed portion is fixed to the forging machine and closes the area between the lower die and the upper die by contacting the mating part of the upper die and the lower die, and an elastic member that biases the movable portion toward the mating part relative to the fixed portion when the fixed portion is fixed to the forging machine.

[0011] With this configuration, the mold of the present invention maintains a closed state in the region between the lower and upper molds due to the biasing force of the elastic member, thus eliminating the need for a hydraulic circuit as in conventional designs, and allowing for a smaller size than conventional designs.

[0012] In the mold of the present invention, when the movable part is in contact with the mating part, the movement of the fixed part relative to the mating part in the direction of biasing the movable part relative to the fixed part by the elastic member may be restricted by the contact between the fixed part and the movable part.

[0013] With this configuration, in the mold of the present invention, when the movable part is in contact with the mating part, the movement of the fixed part relative to the mating part in the direction of biasing of the movable part by the elastic member is restricted by the contact between the fixed part and the movable part. Therefore, when the movement of the fixed part relative to the mating part is restricted, the movement of the movable part relative to the fixed part in the direction opposite to the biasing direction of the movable part by the elastic member is restricted by the contact between the fixed part and the movable part. As a result, the possibility of forging material protruding as burrs from the gap between the movable part and the mating part can be reduced.

[0014] In the mold of the present invention, the rotation of the movable part with respect to the mating part around a specific straight line extending in the vertical direction may be limited by the meshing of the mating part and the movable part.

[0015] With this configuration, the mold of the present invention has its rotation of the movable part relative to the mating part around a specific line extending vertically restricted by the meshing of the mating part and the movable part. Therefore, the possibility of deterioration in the quality of the forged product due to the rotation of the movable part relative to the mating part around a specific line extending vertically can be reduced.

[0016] In the mold of the present invention, the upper mold may include the fixed portion, the movable portion, and the elastic member.

[0017] With this configuration, the mold of the present invention, since the upper mold comprises a fixed part, a movable part, and an elastic member, can maintain a closed state between the lower mold and the upper mold not only by the biasing force of the elastic member of the upper mold but also by the weight of the movable part of the upper mold. Therefore, the elastic member of the upper mold of the present invention can be miniaturized, and as a result, the mold can be made more compact.

[0018] In the mold of the present invention, the elastic member may be a compression coil spring.

[0019] With this configuration, the mold of the present invention can be realized with a simple structure because the elastic member is a compression coil spring.

[0020] The present invention relates to a method for manufacturing forged products, comprising a method for manufacturing forged products by closed forging using a die by warm forging or hot forging, wherein the die comprises a lower die and an upper die fixed to a forging machine, and at least one of the upper die and the lower die comprises a fixed portion fixed to the forging machine, a movable portion that is movable vertically relative to the fixed portion when the fixed portion is fixed to the forging machine and closes the area between the lower die and the upper die by contacting the mating part of the upper die and the lower die, and an elastic member that biases the movable portion toward the mating part relative to the fixed portion when the fixed portion is fixed to the forging machine.

[0021] With this configuration, the forging method of the present invention can manufacture forged products using a smaller mold than conventional methods, thereby reducing the manufacturing cost of the mold and, as a result, reducing the manufacturing cost of the forged products. [Effects of the Invention]

[0022] The mold and forging method of the present invention can be made smaller than conventional methods. [Brief explanation of the drawing]

[0023] [Figure 1]It is a partial front cross-sectional view of a forging machine to which a mold according to the first embodiment of the present invention is attached. [Figure 2] It is a plan view of the lower mold shown in FIG. 1. [Figure 3] It is a bottom view of the upper mold shown in FIG. 1. [Figure 4] It is an external perspective view of the material forged by the mold shown in FIG. 1. [Figure 5] It is a partial front cross-sectional view of the forging machine shown in FIG. 1 in a state where the material is set in the lower mold. [Figure 6] It is a partial front cross-sectional view of the forging machine shown in FIG. 1 in a state where the punch contacts the material. [Figure 7] It is a partial front cross-sectional view of the forging machine shown in FIG. 1 in a state where the region between the lower mold and the upper mold is closed. [Figure 8] It is a partial front cross-sectional view of the forging machine shown in FIG. 1 in a state where the forming of the material by the punch is completed. [Figure 9] It is a partial front cross-sectional view of the forging machine shown in FIG. 1 in a state where the forged product is pushed up by the knockout part. [Figure 10] It is a partial front cross-sectional view of a forging machine to which a mold according to the second embodiment of the present invention is attached. [Figure 11] It is an external perspective view of the material forged by the mold shown in FIG. 10. [Figure 12] It is a partial front cross-sectional view of the forging machine shown in FIG. 10 in a state where the material is set in the lower mold. [Figure 13] It is a partial front cross-sectional view of the forging machine shown in FIG. 10 in a state where the region between the lower mold and the upper mold is closed. [Figure 14] It is a partial front cross-sectional view of the forging machine shown in FIG. 10 in a state where the forming of the material by the punch is completed. [Figure 15] It is a partial front cross-sectional view of the forging machine shown in FIG. 10 in a state where the forged product is pushed up by the knockout part. [Figure 16] It is a partial front cross-sectional view of a forging machine to which a mold according to the third embodiment of the present invention is attached. [Figure 17] Figure 16 is a perspective view of the material being forged by the die shown. [Figure 18] This is a front cross-sectional view of a part of the forging machine shown in Figure 16, with the material set in the lower die. [Figure 19] This is a front cross-sectional view of a part of the forging machine shown in Figure 16, with the punch in contact with the material. [Figure 20] This is a front cross-sectional view of a part of the forging machine shown in Figure 16, with the area between the lower and upper dies closed. [Figure 21] Figure 16 shows a front cross-sectional view of a part of a forging machine after the material has been formed by punching. [Figure 22] Figure 16 is a front cross-sectional view of a part of a forging machine, showing the forged product in the state where it has been pushed up by the knockout section. [Modes for carrying out the invention]

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0025] (First Embodiment) First, the configuration of the mold according to the first embodiment of the present invention will be described.

[0026] Figure 1 is a front cross-sectional view of a part of a forging machine 10 to which the mold 20 according to this embodiment is attached.

[0027] As shown in Figure 1, the forging machine 10 includes a bolster 11 to which the lower die of the die is attached, a plurality of lower die fixing members 12 for fixing the lower die to the bolster 11, a drive member 13 as a member for driving the knockout member of the die, which will be described later, a ram 14 to which the upper die of the die is attached and which is movable vertically relative to the bolster 11, and a plurality of upper die fixing members 15 for fixing the upper die to the ram 14. The forging method of the forging machine 10 may be, for example, a screw press.

[0028] The multiple lower mold fixing members 12 are arranged one by one at specific angular intervals, such as 90 degrees, centered on a specific straight line 10a that extends in the vertical direction.

[0029] As described above, the drive member 13 is a member that drives the knockout member of the mold. The knockout member of the mold is a member that makes it easier to remove the forged product manufactured by the mold from the lower mold.

[0030] Multiple upper mold fixing members 15 are arranged one by one at specific angular intervals, such as 90 degrees, with respect to the straight line 10a.

[0031] The mold 20 includes a lower mold 30 attached to the bolster 11 side and an upper mold 40 attached to the ram 14 side.

[0032] Figure 2 is a plan view of the lower mold 30.

[0033] As shown in Figures 1 and 2, the lower mold 30 has a fixing groove 30a formed on its outer circumference, which serves as a groove into which a part of the lower mold fixing member 12 is inserted in order to fix the lower mold 30 to the bolster 11.

[0034] The lower mold 30 has an upper mold projection 30b which protrudes in an upward direction in the vertical direction when the lower mold 30 is attached to the bolster 11 and is inserted into the upper mold 40. The upper mold projection 30b has a lower mold side region groove 30c which is a groove for forming a region between it and the upper mold 40, and a lower mold side closing surface 30d which is a surface that closes the region between the lower mold 30 and the upper mold 40 formed at its end.

[0035] The lower die 30 comprises a main body 31 having a fixing groove 30a, a replaceable part 32 that is replaceable with respect to the main body 31 and has a projection 30b for the upper die, a holder 33 for fixing the replaceable part 32 to the main body 31, a plurality of bolts 34 for fixing the holder 33 to the main body 31, and a knockout member 35 as a member for making it easier to remove the forged product from the lower die 30.

[0036] The main body 31 has a screw hole 31a formed therein for fixing the bolt 34.

[0037] The upper mold projection 30b of the replaceable section 32 has two flat sections 30e on its sides.

[0038] The multiple bolts 34 are arranged one at a time at specific angular intervals, such as 90 degrees, with respect to the straight line 10a when the lower mold 30 is fixed to the bolster 11.

[0039] Figure 3 is a bottom view of the upper mold 40.

[0040] As shown in Figures 1 and 3, the upper mold 40 has a fixing groove 40a formed on its outer circumference, which serves as a groove into which a part of the upper mold fixing member 15 is inserted in order to fix the upper mold 40 to the ram 14.

[0041] The upper mold 40 includes a lower mold groove 40b into which the upper mold projection 30b is inserted, an upper mold side region groove 40d formed within the lower mold groove 40b to form a region together with the lower mold side region groove 30c, and two gas venting holes 40e that communicate with the lower mold groove 40b.

[0042] The lower mold groove 40b has two flat sections 40c on its sides.

[0043] The gas venting hole 40e is a hole that allows the air inside the space formed by the upper mold projection 30b and the lower mold groove 40b when the upper mold projection 30b of the lower mold 30 is inserted into the lower mold groove 40b of the upper mold 40 to escape to the outside of this space.

[0044] The upper mold 40 includes a fixed portion 50 that is fixed to the ram 14, a movable portion 60 that is movable relative to the fixed portion 50 in a direction that is vertical when the upper mold 40 is attached to the ram 14, a plurality of stripper bolts 41 to prevent the movable portion 60 from separating from the fixed portion 50, and a plurality of springs 42 as elastic members that bias the movable portion 60 relative to the fixed portion 50 in a downward direction in the vertical direction when the upper mold 40 is attached to the ram 14.

[0045] The fixed portion 50 includes a punch 50a, which is a substantially cylindrical projection that protrudes in a direction that is vertically downward when the upper die 40 is attached to the ram 14 and is inserted into the movable portion 60, and a fixed portion side movement limiting portion 50b that restricts the vertical upward movement of the movable portion 60 when it comes into contact with the movable portion 60.

[0046] The fixing part 50 comprises a main body 51, a replaceable part 52 that is replaceable with respect to the main body 51, a bolt 53 for fixing the replaceable part 52 to the main body 51, and a pin 54 for preventing the replaceable part 52 from rotating relative to the main body 51.

[0047] The main body 51 has a fixing groove 40a, a stripper bolt hole 51a as a hole into which a stripper bolt 41 is inserted, and a spring groove 51b as a groove into which a spring 42 is inserted. The main body 51 has a retaining part 51c to prevent the stripper bolt 41 from coming out of the stripper bolt hole 51a by contact with the head of the stripper bolt 41, and a replaceable part mounting part 51d as a substantially cylindrical projection that protrudes in a direction that is vertically downward when the upper mold 40 is attached to the ram 14 and is inserted into the movable part 60. The replaceable part mounting part 51d has a replaceable part groove 51e as a groove into which a replaceable part 52 is inserted, a screw hole 51f for fixing a bolt 53, and a screw hole 51g for fixing a pin 54 formed at its end.

[0048] The replaceable section 52 has a bolt hole 52a into which a bolt 53 is inserted, and a pin groove 52b into which a pin 54 is inserted.

[0049] The punch 50a is composed of a replaceable part mounting part 51d and a replaceable part 52.

[0050] The movable part 60 has a lower die groove 40b, an upper die side closing surface 60a which closes the area between the lower die side groove 30c and the upper die side groove 40d by contacting the lower die side closing surface 30d, a punch hole 60b into which the punch 50a of the fixed part 50 is inserted, a screw hole 60c for fixing the stripper bolt 41, and a spring groove 60d into which the spring 42 is inserted. The movable part 60 is equipped with a movable part side movement limiting part 60e which restricts the downward movement of the fixed part 50 in the vertical direction when it comes into contact with the fixed part 50.

[0051] The multiple stripper bolts 41 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 40 is fixed to the ram 14.

[0052] The spring 42 is, for example, a compression coil spring. Multiple springs 42 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 40 is fixed to the ram 14.

[0053] The rotation of the movable part 60 relative to the lower mold 30 is restricted by the contact between the flat surface 30e (see Figure 2) of the upper mold projection 30b of the lower mold 30 and the flat surface 40c of the lower mold groove 40b of the upper mold 40, that is, by the engagement of the upper mold projection 30b and the lower mold groove 40b.

[0054] Next, we will explain the method for manufacturing forged products using the mold 20.

[0055] The mold 20 is used to manufacture forged products by closed forging using warm forging or hot forging.

[0056] Figure 4 is an external perspective view of the material 91 being forged by the mold 20.

[0057] As shown in Figure 4, the shape of the material 91 forged by the mold 20 is cylindrical. The material of the material 91 is, for example, brass.

[0058] Figure 5 is a front cross-sectional view of a part of the forging machine 10 with the material 91 set in the lower die 30.

[0059] When a forged product is manufactured using the mold 20, a solution in which carbon particles are dispersed in water or an organic solvent is sprayed onto the mold 20 as a lubricant. The application of the lubricant to the mold 20 makes it easier for the material 91 to flow into the mold 20 and easier to remove the forged product from the mold 20. After the lubricant is applied to the mold 20, the heated material 91 is set into the lower mold 30 so as to be inserted into the groove 30c for the lower mold side region, as shown in Figure 5.

[0060] Figure 6 is a front cross-sectional view of a portion of the forging machine 10 with the punch 50a in contact with the material 91.

[0061] As shown in Figure 5, after the material 91 is set in the lower die 30, the ram 14 of the forging machine 10 is moved downward in the vertical direction, causing the punch 50a to come into contact with the material 91, as shown in Figure 6.

[0062] Figure 7 is a front cross-sectional view of a portion of the forging machine 10 with the area 20a between the lower die 30 and the upper die 40 closed.

[0063] As shown in Figure 6, after the punch 50a contacts the material 91, the ram 14 of the forging machine 10 is moved further downward in the vertical direction, so that the upper die-side closing surface 60a contacts the lower die-side closing surface 30d, as shown in Figure 7. Therefore, the area 20a between the lower die-side region groove 30c and the upper die-side region groove 40d becomes closed. Also, the material 91 is deformed by the punch 50a.

[0064] Figure 8 is a front cross-sectional view of a portion of the forging machine 10 after the material 91 has been formed by the punch 50a.

[0065] As shown in Figure 7, after region 20a is closed, the ram 14 of the forging machine 10 is moved further downward in the vertical direction, so that as shown in Figure 8, the material 91 is formed by the punch 50a and a forged product 92 is manufactured. Here, from the time the forming of the material 91 by the punch 50a is started until the forming of the material 91 by the punch 50a is completed, the biasing force of the spring 42 presses the upper die-side closing surface 60a of the movable part 60 against the lower die-side closing surface 30d of the lower die 30, so that region 20a remains closed. However, some excess material 91 may protrude as burrs from the gap between the lower die 30 and the upper die 40.

[0066] In the state shown in Figure 8, the biasing direction of the movable part 60 relative to the fixed part 50 by the spring 42, that is, the downward movement of the fixed part 50 relative to the lower mold 30 in the vertical direction, is restricted by the contact between the fixed part side movement limiting part 50b of the fixed part 50 and the movable part side movement limiting part 60e of the movable part 60.

[0067] Figure 9 is a front cross-sectional view of a portion of the forging machine 10 in a state where the forged product 92 is being pushed up by the knockout member 35.

[0068] As shown in Figure 8, after the forged product 92 is manufactured, the ram 14 of the forging machine 10 is moved vertically upward, and the drive member 13 of the forging machine 10 is moved vertically upward, so that as shown in Figure 9, the forged product 92 is pushed up by the knockout member 35 which has been moved vertically upward by the drive member 13. Therefore, the forged product 92 is easily removed from the forging machine 10.

[0069] The forged product 92 is removed from the forging machine 10 and allowed to cool naturally, after which it is completed as a synchronizer ring by undergoing the necessary processing. The necessary processing includes, for example, cutting of certain parts of the forged product 92, such as the inner diameter or end faces (for example, if the material 91 is made of iron, grinding may be performed in addition to cutting), and heat treatment or surface treatment performed after cutting (or after grinding, if grinding is performed).

[0070] As described above, since the mold 20 maintains a closed state in the region 20a between the lower mold 30 and the upper mold 40 by the biasing force of the spring 42, it does not require a hydraulic circuit as in the conventional design, and can be made smaller than conventional designs.

[0071] When the movable part 60 of the mold 20 is in contact with the lower mold 30, the direction in which the movable part 60 is biased by the spring 42 relative to the fixed part 50, i.e., the downward movement of the fixed part 50 relative to the lower mold 30 in the vertical direction, can be restricted by the contact between the fixed part 50 and the movable part 60. Therefore, when the movement of the fixed part 50 relative to the lower mold 30 is restricted, the upward movement of the movable part 60 relative to the fixed part 50 in the vertical direction is restricted by the contact between the fixed part 50 and the movable part 60. As a result, the possibility of the forging material 91 protruding as burrs from the gap between the movable part 60 and the lower mold 30 can be reduced.

[0072] In the mold 20, the rotation of the movable part 60 relative to the lower mold 30 around the straight line 10a is restricted by the engagement between the upper mold projection 30b of the lower mold 30 and the lower mold groove 40b of the movable part 60. Therefore, the possibility of a decrease in the quality of the forged product 92 due to the rotation of the movable part 60 relative to the lower mold 30 around the straight line 10a can be reduced.

[0073] Since the mold 20 has an upper mold 40 that includes a fixed part 50, a movable part 60, and a spring 42, the region 20a between the lower mold 30 and the upper mold 40 can be kept closed not only by the biasing force of the spring 42 but also by the weight of the movable part 60. Therefore, the mold 20 can be made smaller because the spring 42 can be miniaturized.

[0074] Since the mold 20 maintains a closed state in the region 20a between the lower mold 30 and the upper mold 40 by the biasing force of the spring 42, it does not require a hydraulic circuit as in the conventional method, and can be realized with a simpler configuration than in the conventional method.

[0075] Since the mold 20 uses a compression coil spring as the spring 42, it can be implemented with a simple configuration.

[0076] Since the mold 20 is smaller and simpler than conventional molds, the manufacturing cost of the mold 20 itself can be reduced. Therefore, the manufacturing cost of the forged product 92 can be reduced.

[0077] Since the mold 20 can achieve closed-circuit forging, the amount of burrs generated on the outer circumference of the forged product 92 can be reduced.

[0078] The mold 20 can form forged products of various shapes by replacing at least one of the replaceable parts of the lower mold 30 and the upper mold 40.

[0079] When a forged product with a different outer diameter than the forged product 92 is to be formed by the forging machine 10, a mold with a similar configuration to the mold 20, but with a different diameter in the area between the lower and upper molds, can be set in the forging machine 10 in place of the mold 20 for forming. Since the mold of the present invention is smaller than conventional molds, the replacement work on the forging machine 10 is easy.

[0080] Since the mold 20 is small, it can be set in place of the mold used for deburring in a forging machine used for deburring. For example, the mold 20 can be set in a forging machine equipped with an automatic transport function that is used for deburring.

[0081] (Second Embodiment) First, the configuration of the mold according to the second embodiment of the present invention will be described.

[0082] Figure 10 is a front cross-sectional view of a part of a forging machine 10 to which the mold 120 according to this embodiment is attached.

[0083] The forging machine 10 shown in Figure 10 is identical to the forging machine 10 according to the first embodiment.

[0084] The die 120 comprises a lower die 130 attached to the bolster 11 side of the forging machine 10 and an upper die 140 attached to the ram 14 side of the forging machine 10.

[0085] The lower mold 130 has a fixing groove 130a formed on its outer circumference, which serves as a groove into which a part of the lower mold fixing member 12 is inserted in order to fix the lower mold 130 to the bolster 11.

[0086] The lower mold 130 has an upper mold projection 130b that protrudes in an upward direction in the vertical direction when the lower mold 130 is attached to the bolster 11 and is inserted into the upper mold 140. The upper mold projection 130b has a lower mold side region groove 130c formed at its end as a groove for forming a region between it and the upper mold 140, and a lower mold side closing surface 130d formed as a surface that closes the region between the lower mold 130 and the upper mold 140.

[0087] The lower die 130 comprises a main body 131 having a fixing groove 130a and a projection 130b for the upper die, a knockout member 132 as a member for easily removing the forged product from the lower die 130, a spring 133 for biasing the knockout member 132 downward relative to the main body 131, a retaining member 134 as a member for preventing the knockout member 132 from coming out of the main body 131, and a plurality of bolts 135 for fixing the retaining member 134 to the main body 131.

[0088] The knockout member 132 is provided with a knockout portion 132a for pressing the forged product.

[0089] The spring 133 has a knockout portion 132a inserted on its inner circumference.

[0090] The multiple bolts 135 are arranged one at a time at specific angular intervals, such as 90 degrees, with respect to the straight line 10a when the lower mold 130 is fixed to the bolster 11.

[0091] The upper mold 140 has a fixing groove 140a formed on its outer circumference, which serves as a groove into which a part of the upper mold fixing member 15 is inserted in order to fix the upper mold 140 to the ram 14.

[0092] The upper mold 140 includes a lower mold groove 140b into which the upper mold projection 130b is inserted, and an upper mold side region groove 140d formed within the lower mold groove 140b to form a region together with the lower mold side region groove 130c.

[0093] The upper mold 140 includes a fixed portion 150 that is fixed to the ram 14, a movable portion 160 that is movable relative to the fixed portion 150 in a direction that is vertical when the upper mold 140 is attached to the ram 14, a plurality of stripper bolts 141 to prevent the movable portion 160 from separating from the fixed portion 150, and a plurality of springs 142 as elastic members that bias the movable portion 160 relative to the fixed portion 150 in a direction that is vertically downward when the upper mold 140 is attached to the ram 14.

[0094] The fixing part 150 has a fixing groove 140a, a stripper bolt hole 150a as a hole into which a stripper bolt 141 is inserted, and a spring groove 150b as a groove into which a spring 142 is inserted. The fixing part 150 includes a retaining part 150c to prevent the stripper bolt 141 from coming out of the stripper bolt hole 150a when the head of the stripper bolt 141 comes into contact with it, a punch 150d as a substantially cylindrical projection that protrudes in a direction that is vertically downward when the upper die 140 is attached to the ram 14 and is inserted into the movable part 160, and a fixing part side movement limiting part 150e that restricts the vertical upward movement of the movable part 160 when it comes into contact with the movable part 160.

[0095] The movable part 160 has a lower die groove 140b, an upper die side closing surface 160a which closes the area between the lower die side groove 130c and the upper die side groove 140d by contacting the lower die side closing surface 130d, a punch hole 160b into which the punch 150d of the fixed part 150 is inserted, a screw hole 160c for fixing the stripper bolt 141, and a spring groove 160d into which the spring 142 is inserted. The movable part 160 is equipped with a movable part side movement limiting part 160e which restricts the downward movement of the fixed part 150 in the vertical direction when it comes into contact with the fixed part 150.

[0096] The multiple stripper bolts 141 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 140 is attached to the ram 14.

[0097] The spring 142 is, for example, a compression coil spring. Multiple springs 142 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 140 is fixed to the ram 14.

[0098] The rotation of the movable part 160 relative to the lower mold 130 is limited, as in the first embodiment, by the engagement between the upper mold projection 130b of the lower mold 130 and the lower mold groove 140b of the movable part 160.

[0099] Next, we will explain the manufacturing method of forged products using the mold 120.

[0100] The mold 120 is used to manufacture forged products by closed forging using warm forging or hot forging.

[0101] Figure 11 is an external perspective view of the material 191 being forged by the mold 120.

[0102] As shown in Figure 11, the shape of the material 191 forged by the mold 120 is cylindrical. The material of the material 191 is, for example, brass.

[0103] Figure 12 is a front cross-sectional view of a part of the forging machine 10 with the material 191 set in the lower die 130.

[0104] When a forged product is manufactured using the mold 120, a solution of carbon particles dispersed in water or an organic solvent is sprayed onto the mold 120 as a lubricant. The application of the lubricant to the mold 120 makes it easier for the material 191 to flow into the mold 120 and easier to remove the forged product from the mold 120. After the lubricant is applied to the mold 120, the heated material 191 is set into the lower mold 130 so as to be inserted into the groove 130c for the lower mold side region, as shown in Figure 12.

[0105] Figure 13 is a front cross-sectional view of a portion of the forging machine 10 with the area 120a between the lower die 130 and the upper die 140 closed.

[0106] As shown in Figure 12, after the material 191 is set in the lower die 130, the ram 14 of the forging machine 10 is moved downward in the vertical direction, causing the upper die side closing surface 160a to come into contact with the lower die side closing surface 130d, as shown in Figure 13. Therefore, the area 120a between the lower die side groove 130c and the upper die side groove 140d becomes closed.

[0107] Figure 14 is a front cross-sectional view of a portion of the forging machine 10 after the material 191 has been formed by the punch 150d.

[0108] As shown in Figure 13, after region 120a is closed, the ram 14 of the forging machine 10 is moved further downward in the vertical direction, so that as shown in Figure 14, the material 191 is shaped by the punch 150d and a forged product 192 is manufactured. Here, from the time the shaping of the material 191 by the punch 150d begins until the shaping of the material 191 by the punch 150d is completed, the biasing force of the spring 142 presses the upper die-side closing surface 160a of the movable part 160 against the lower die-side closing surface 130d of the lower die 130, so that region 120a remains closed. However, excess material 191 may protrude as burrs from the gap between the lower die 130 and the upper die 140.

[0109] In the state shown in Figure 14, the biasing direction of the movable part 160 relative to the fixed part 150 by the spring 142, that is, the downward movement of the fixed part 150 relative to the lower mold 130 in the vertical direction, is restricted by contact between the fixed part side movement limiting part 150e of the fixed part 150 and the movable part side movement limiting part 160e of the movable part 160.

[0110] Figure 15 is a front cross-sectional view of a portion of the forging machine 10 in a state where the forged product 192 is pushed up by the knockout portion 132a.

[0111] As shown in Figure 14, after the forged product 192 is manufactured, the ram 14 of the forging machine 10 is moved vertically upward, and the drive member 13 of the forging machine 10 is moved vertically upward, so that as shown in Figure 15, the forged product 192 is pushed up by the knockout portion 132a of the knockout member 132 which has been moved vertically upward by the drive member 13. Therefore, the forged product 192 is easier to remove from the forging machine 10.

[0112] The forged product 192 is removed from the forging machine 10 and allowed to cool naturally, after which it is processed as necessary to complete it as an impeller or bevel gear. Here, the necessary processing may include, for example, machining of parts of the forged product 192, such as the inner diameter or end faces, as well as further processing required depending on the material of the material 191 and the required quality of the finished product.

[0113] As described above, since the mold 120 maintains a closed state in the region 120a between the lower mold 130 and the upper mold 140 due to the biasing force of the spring 142, it does not require a hydraulic circuit as in the conventional design, and can be made smaller than conventional designs.

[0114] In the mold 120, when the movable part 160 is in contact with the lower mold 130, the direction in which the movable part 160 is biased by the spring 142 relative to the fixed part 150, i.e., the downward movement of the fixed part 150 relative to the lower mold 130 in the vertical direction, can be restricted by the contact between the fixed part 150 and the movable part 160. Therefore, when the movement of the fixed part 150 relative to the lower mold 130 is restricted, the upward movement of the movable part 160 relative to the fixed part 150 in the vertical direction is restricted by the contact between the fixed part 150 and the movable part 160. As a result, the possibility of the forging material 191 protruding as burrs from the gap between the movable part 160 and the lower mold 130 can be reduced.

[0115] In the mold 120, the rotation of the movable part 160 relative to the lower mold 130 around the straight line 10a is restricted by the engagement between the upper mold projection 130b of the lower mold 130 and the lower mold groove 140b of the movable part 160. Therefore, the possibility of a decrease in the quality of the forged product 192 due to the rotation of the movable part 160 relative to the lower mold 130 around the straight line 10a can be reduced.

[0116] Since the upper mold 140 of the mold 120 includes a fixed part 150, a movable part 160, and a spring 142, the region 120a between the lower mold 130 and the upper mold 140 can be kept closed not only by the biasing force of the spring 142 but also by the weight of the movable part 160. Therefore, the spring 142 of the mold 120 can be miniaturized, and as a result, the mold 120 can be made smaller.

[0117] Since the mold 120 maintains a closed state in the region 120a between the lower mold 130 and the upper mold 140 due to the biasing force of the spring 142, it does not require a hydraulic circuit as in the conventional method, and can be realized with a simpler configuration than in the conventional method.

[0118] Since the mold 120 uses a compression coil spring as the spring 142, it can be implemented with a simple configuration.

[0119] Since the mold 120 is smaller and simpler than conventional molds, the manufacturing cost of the mold 120 itself can be reduced. Therefore, the manufacturing cost of the forged product 192 can be reduced.

[0120] When the forging machine 10 is to form a forged product with a different outer diameter than the forged product 192, a mold with a similar configuration to the mold 120, but with a different diameter in the region between the lower and upper molds, can be set in the forging machine 10 in place of the mold 120 for forming. Since the mold of the present invention is smaller than conventional molds, the replacement work on the forging machine 10 is easy.

[0121] Since the mold 120 is small, it can be set in place of the mold used for deburring in a forging machine used for deburring. For example, the mold 120 can be set in a forging machine equipped with an automatic transport function that is used for deburring.

[0122] (Third embodiment) First, the configuration of the mold according to the third embodiment of the present invention will be described.

[0123] Figure 16 is a front cross-sectional view of a part of a forging machine 10 to which the mold 220 according to this embodiment is attached.

[0124] The forging machine 10 shown in Figure 16 is identical to the forging machine 10 according to the first embodiment.

[0125] The die 220 comprises a lower die 230 attached to the bolster 11 side of the forging machine 10 and an upper die 240 attached to the ram 14 side of the forging machine 10.

[0126] The lower mold 230 has a fixing groove 230a formed on its outer circumference, which serves as a groove into which a part of the lower mold fixing member 12 is inserted in order to fix the lower mold 230 to the bolster 11.

[0127] The lower mold 230 is provided with an upper mold projection 230b, which protrudes in an upward direction in the vertical direction when the lower mold 230 is attached to the bolster 11 and is inserted into the upper mold 240. The upper mold projection 230b has a lower mold side region groove 230c formed at its end as a groove for forming a region between it and the upper mold 240, and a lower mold side closing surface 230d formed as a surface that closes the region between the lower mold 230 and the upper mold 240.

[0128] The lower die 230 comprises a main body 231 having a fixing groove 230a and a projection 230b for the upper die, a knockout member 232 as a member for easily removing the forged product from the lower die 230, a plurality of springs 233 that bias the knockout member 232 downward relative to the main body 231, a retaining member 234 as a member for preventing the knockout member 232 from coming out of the main body 231, and a plurality of bolts 235 for fixing the retaining member 234 to the main body 231.

[0129] The knockout member 232 is provided with a knockout portion 232a for pressing the forged product.

[0130] The multiple springs 233 are arranged one by one at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the lower mold 230 is fixed to the bolster 11.

[0131] The multiple bolts 235 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the lower mold 230 is fixed to the bolster 11.

[0132] The upper mold 240 has a fixing groove 240a formed on its outer circumference, which serves as a groove into which a part of the upper mold fixing member 15 is inserted in order to fix the upper mold 240 to the ram 14.

[0133] The upper mold 240 includes a lower mold groove 240b into which the upper mold projection 230b is inserted, and an upper mold side region groove 240d formed within the lower mold groove 240b to form a region together with the lower mold side region groove 230c.

[0134] The upper mold 240 includes a fixed portion 250 that is fixed to the ram 14, a movable portion 260 that is movable relative to the fixed portion 250 in a direction that is vertical when the upper mold 240 is attached to the ram 14, a plurality of stripper bolts 241 to prevent the movable portion 260 from separating from the fixed portion 250, and a plurality of springs 242 as elastic members that bias the movable portion 260 relative to the fixed portion 250 in a direction that is vertically downward when the upper mold 240 is attached to the ram 14.

[0135] The fixed portion 250 is equipped with a fixed portion-side movement limiting portion 250a that restricts the upward movement of the movable portion 260 in the vertical direction when it comes into contact with the movable portion 260.

[0136] The fixing part 250 comprises a main body 251, a punch 252 which is a substantially cylindrical projection that protrudes in a direction that is vertically downward when the upper die 240 is attached to the ram 14 and is inserted into the movable part 260, a retaining member 253 which is a member that prevents the punch 252 from coming out of the main body 251, and a plurality of bolts 254 for fixing the retaining member 253 to the main body 251.

[0137] The multiple bolts 254 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 240 is attached to the ram 14.

[0138] The main body 251 has a fixing groove 240a, a stripper bolt hole 251a into which the stripper bolt 241 is inserted, and a spring groove 251b into which the spring 242 is inserted. The fixing part 250 is equipped with a retaining part 251c to prevent the stripper bolt 241 from coming out of the stripper bolt hole 251a due to contact with the head of the stripper bolt 241.

[0139] The movable part 260 has a lower die groove 240b, an upper die side closing surface 260a which closes the area between the lower die side groove 230c and the upper die side groove 240d by contacting the lower die side closing surface 230d, a punch hole 260b into which the punch 252 of the fixed part 250 is inserted, a screw hole 260c for fixing the stripper bolt 241, and a spring groove 260d into which the spring 242 is inserted. The movable part 260 is equipped with a movable part side movement limiting part 260e which restricts the downward vertical movement of the fixed part 250 when it comes into contact with the fixed part 250.

[0140] The multiple stripper bolts 241 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 240 is attached to the ram 14.

[0141] The spring 242 is, for example, a compression coil spring. Multiple springs 242 are arranged one at a time at specific angular intervals, such as 120 degrees, with respect to the straight line 10a when the upper mold 40 is fixed to the ram 14.

[0142] The rotation of the movable part 260 relative to the lower mold 230 is limited, as in the first embodiment, by the engagement between the upper mold projection 230b of the lower mold 230 and the lower mold groove 240b of the movable part 260.

[0143] Next, we will explain the manufacturing method of forged products using the mold 220.

[0144] The mold 220 is used to manufacture forged products by closed forging using warm forging or hot forging.

[0145] Figure 17 is an external perspective view of the material 291 being forged by the mold 220.

[0146] As shown in Figure 17, the shape of the material 291 forged by the mold 220 is cylindrical. The material of the material 291 is, for example, brass.

[0147] Figure 18 is a front cross-sectional view of a part of the forging machine 10 with the material 291 set in the lower die 230.

[0148] When a forged product is manufactured using the mold 220, a solution of carbon particles dispersed in water or an organic solvent is sprayed onto the mold 220 as a lubricant. The application of the lubricant to the mold 220 makes it easier for the material 291 to flow into the mold 220 and easier to remove the forged product from the mold 220. After the lubricant is applied to the mold 220, the heated material 291 is set in the lower mold 230 so as to be inserted into the groove 230c for the lower mold side region, as shown in Figure 18.

[0149] Figure 19 is a front cross-sectional view of a portion of the forging machine 10 with the punch 252 in contact with the material 291.

[0150] As shown in Figure 18, after the material 291 is set in the lower die 230, the ram 14 of the forging machine 10 is moved downward in the vertical direction, causing the punch 252 to come into contact with the material 291, as shown in Figure 19.

[0151] Figure 20 is a front cross-sectional view of a portion of the forging machine 10 with the area 220a between the lower die 230 and the upper die 240 closed.

[0152] As shown in Figure 19, after the punch 252 contacts the material 291, the ram 14 of the forging machine 10 is moved further downward in the vertical direction, so that the upper die-side closing surface 260a contacts the lower die-side closing surface 230d, as shown in Figure 20. Therefore, the area 220a between the lower die-side groove 230c and the upper die-side groove 240d becomes closed. The material 291 is also deformed by the punch 252.

[0153] Figure 21 is a front cross-sectional view of a portion of the forging machine 10 after the material 291 has been formed by the punch 252.

[0154] As shown in Figure 20, after region 220a is closed, the ram 14 of the forging machine 10 is moved further downward in the vertical direction, so that the material 291 is shaped by the punch 252 and a forged product 292 is manufactured, as shown in Figure 21. Here, from the time the shaping of the material 291 by the punch 252 begins until the shaping of the material 291 by the punch 252 is completed, the biasing force of the spring 242 presses the upper die-side closing surface 260a of the movable part 260 against the lower die-side closing surface 230d of the lower die 230, so that region 220a remains closed. However, some excess material 291 may protrude as burrs from the gap between the lower die 230 and the upper die 240.

[0155] In the state shown in Figure 21, the biasing direction of the movable part 260 relative to the fixed part 250 by the spring 242, that is, the downward movement of the fixed part 250 relative to the lower mold 230 in the vertical direction, is restricted by contact between the fixed part side movement limiting part 250a of the fixed part 250 and the movable part side movement limiting part 260e of the movable part 260.

[0156] Figure 22 is a front cross-sectional view of a portion of the forging machine 10 with the forged product 292 being pushed up by the knockout portion 232a.

[0157] As shown in Figure 21, after the forged product 292 is manufactured, the ram 14 of the forging machine 10 is moved vertically upward, and the drive member 13 of the forging machine 10 is moved vertically upward, so that as shown in Figure 22, the forged product 292 is pushed up by the knockout portion 232a of the knockout member 232 which has been moved vertically upward by the drive member 13. Therefore, the forged product 292 is easily removed from the forging machine 10.

[0158] The forged product 292 is removed from the forging machine 10 and allowed to cool naturally, after which it is processed as necessary to complete it as a hollow headed bolt or the like. Here, the necessary processing may include, for example, machining of parts of the forged product 292 such as the inner diameter and end faces, as well as further processing required depending on the material 291 and the required quality of the finished product.

[0159] As described above, since the mold 220 maintains a closed state in the region 220a between the lower mold 230 and the upper mold 240 by the biasing force of the spring 242, it does not require a hydraulic circuit as in the conventional design, and can be made smaller than conventional designs.

[0160] In the mold 220, when the movable part 260 is in contact with the lower mold 230, the direction in which the movable part 260 is biased by the spring 242 relative to the fixed part 250, i.e., the downward movement of the fixed part 250 relative to the lower mold 230 in the vertical direction, can be restricted by the contact between the fixed part 250 and the movable part 260. Therefore, when the movement of the fixed part 250 relative to the lower mold 230 is restricted, the upward movement of the movable part 260 relative to the fixed part 250 in the vertical direction is restricted by the contact between the fixed part 250 and the movable part 260. As a result, the possibility of the forging material 291 protruding as burrs from the gap between the movable part 260 and the lower mold 230 can be reduced.

[0161] In the mold 220, the rotation of the movable part 260 relative to the lower mold 230 around the straight line 10a is restricted by the engagement between the upper mold projection 230b of the lower mold 230 and the lower mold groove 240b of the movable part 260. Therefore, the possibility of a decrease in the quality of the forged product 292 due to the rotation of the movable part 260 relative to the lower mold 230 around the straight line 10a can be reduced.

[0162] Since the upper mold 240 of the mold 220 includes a fixed part 250, a movable part 260, and a spring 242, the region 220a between the lower mold 230 and the upper mold 240 can be kept closed not only by the biasing force of the spring 242 but also by the weight of the movable part 260. Therefore, the spring 242 of the mold 220 can be miniaturized, and as a result, the mold 220 can be made smaller.

[0163] Since the mold 220 maintains a closed state in the region 220a between the lower mold 230 and the upper mold 240 due to the biasing force of the spring 242, it does not require a hydraulic circuit as in the conventional method, and can be realized with a simpler configuration than in the conventional method.

[0164] Since the mold 220 uses a compression coil spring as the spring 242, it can be implemented with a simple configuration.

[0165] Since the mold 220 is smaller and simpler than conventional molds, the manufacturing cost of the mold 220 itself can be reduced. Therefore, the manufacturing cost of the forged product 292 can be reduced.

[0166] When the forging machine 10 is to form a forged product with a different outer diameter than the forged product 292, the forging can be performed with a die that has a similar configuration to the die 220, but with a different diameter in the area between the lower die and the upper die, set in place of the die 220 in the forging machine 10. Since the die of the present invention is smaller than conventional dies, the replacement work in the forging machine 10 is easy.

[0167] Since the mold 220 is small, it can be set in place of the mold used for deburring in a forging machine used for deburring. For example, the mold 220 can be set in a forging machine equipped with an automatic transport function that is used for deburring.

[0168] In each of the embodiments described above, the upper die is provided with a fixed part that is fixed to the forging machine, a movable part that is movable vertically relative to the fixed part when the fixed part is fixed to the forging machine, and an elastic member that biases the movable part toward the lower die relative to the fixed part when the fixed part is fixed to the forging machine. However, the die of the present invention may be provided with a lower die that has a fixed part that is fixed to the forging machine, a movable part that is movable vertically relative to the fixed part when the fixed part is fixed to the forging machine, and an elastic member that biases the movable part toward the upper die relative to the fixed part when the fixed part is fixed to the forging machine, either without providing the movable part and spring in the upper die, or with the movable part and spring in the upper die.

[0169] In each of the embodiments described above, the elastic member of the present invention is a compression coil spring. However, the elastic member of the present invention may be composed of a spring other than a compression coil spring, or of a member other than a spring.

[0170] In each of the embodiments described above, the forging machine has a bolster on the side to which the lower die is attached and a ram on the side to which the upper die is attached. However, the forging machine may have rams on both the side to which the lower die is attached and the side to which the upper die is attached. Alternatively, the forging machine may have a ram on the side to which the lower die is attached and a bolster on the side to which the upper die is attached. [Explanation of Symbols]

[0171] 10 Forging machines 10a Straight line 20 molds 30 Lower mold 40 Upper mold 42. Springs (elastic components, compression coil springs) 50 Fixed part 60 Moving parts 120 molds 130 Lower mold 140 Upper mold 142 Springs (elastic components, compression coil springs) 150 Fixed part 160 Moving parts 220 molds 230 Lower mold 240 Upper mold 242 Springs (elastic components, compression coil springs) 250 Fixed part 260 Moving parts

Claims

1. A die used for closed forging by warm forging or hot forging, It comprises a lower die and an upper die that are fixed to the forging machine, At least one of the upper mold and the lower mold is A fixing part that is fixed to the forging machine, When the fixed portion is fixed to the forging machine, a movable portion is provided that is movable vertically relative to the fixed portion and closes the area between the lower die and the upper die by contacting the mating part of the upper die and the lower die, When the fixed portion is fixed to the forging machine, an elastic member biases the movable portion toward the mating side relative to the fixed portion. Equipped with, The state of the movable part includes a contact state in which the movable part is in contact with the mating part, and a non-contact state in which the movable part is not in contact with the mating part. The rotation of the movable part with respect to the mating part around a specific line extending in the vertical direction is limited by the meshing of the mating part and the movable part. The movable part includes a rotation limiting part that restricts the rotation of the movable part relative to the mating part around the straight line by engaging with the mating part. The mold is characterized in that the rotation limiting portion is not engaged with the mating part when the movable part is in a non-contact state with the mating part.

2. The portion of the movable part that contacts the mating part and the portion of the mating part that contacts the movable part are provided with a structure in which they fit together with each other by interlocking grooves and protrusions, The mold according to claim 1, characterized in that the rotation limiting portion is provided on the portion of the movable portion that constitutes the structure.

3. The upper mold and the lower mold, which include the fixed part, the movable part and the elastic member, are provided with a stripper bolt to prevent the movable part from separating from the fixed part, The mold according to claim 1, characterized in that the stripper bolt restricts the rotation of the movable part with respect to the fixed part around the straight line when the movable part is in a non-contact state with the mating part, by contact between the fixed part and the movable part.

4. The mold according to claim 1, characterized in that the elastic member restricts the rotation of the movable part with respect to the fixed part around the straight line when the movable part is in a non-contact state with the mating part, by contact between the fixed part and the movable part.

5. The mold according to claim 1, characterized in that when the movable part is in contact with the mating part, the movement of the fixed part relative to the mating part in the direction of biasing the movable part relative to the fixed part by the elastic member can be restricted by the contact between the fixed part and the movable part.

6. The mold according to claim 1, characterized in that the upper mold comprises the fixed part, the movable part, and the elastic member.

7. The mold according to claim 1, characterized in that the elastic member is a compression coil spring.

8. A method for manufacturing forged products by closed forging using a die by warm forging or hot forging, The mold comprises a lower die and an upper die that are fixed to the forging machine. At least one of the upper mold and the lower mold is A fixing part that is fixed to the forging machine, When the fixed portion is fixed to the forging machine, a movable portion is provided that is movable vertically relative to the fixed portion and closes the area between the lower die and the upper die by contacting the mating part of the upper die and the lower die, When the fixed portion is fixed to the forging machine, an elastic member biases the movable portion toward the mating side relative to the fixed portion. Equipped with, The state of the movable part includes a contact state in which the movable part is in contact with the mating part, and a non-contact state in which the movable part is not in contact with the mating part. The rotation of the movable part with respect to the mating part around a specific line extending in the vertical direction is limited by the meshing of the mating part and the movable part. The movable part includes a rotation limiting part that restricts the rotation of the movable part relative to the mating part around the straight line by engaging with the mating part. A method for manufacturing forged products, characterized in that the rotation limiting portion is not engaged with the mating part when the movable part is in a non-contact state with the mating part.

9. The upper mold and the lower mold, which include the fixed part, the movable part and the elastic member, are provided with a stripper bolt to prevent the movable part from separating from the fixed part, The method for manufacturing a forged product according to claim 8, characterized in that the stripper bolt restricts the rotation of the movable part with respect to the fixed part around the straight line when the movable part is in a non-contact state with the mating part, by contact between the fixed part and the movable part.

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