Forging device, forging die and forging method

Abstract

To provide a forging device that can easily transport a workpiece to a forging die. [Solution] The forging die comprises a forging die that performs sealed forging on the workpiece W, and a transport mechanism 30 that transports the workpiece W to the forging die. The forging die has an upper die 27 arranged on the upper side in the direction of gravity and a lower die 25 arranged on the lower side in the direction of gravity. The upper die 27 has an upper die restraint wall 27b formed thereon that restrains at least one of the outer peripheral surface and inner peripheral surface of the workpiece, and the lower die 25 has a lower die restraint wall 25b formed thereon that restrains at least one of the outer peripheral surface and inner peripheral surface of the workpiece W. The upper die restraint wall 27b and the lower die restraint wall 25b are formed as a whole around the entire circumference of at least one of the outer peripheral surface and inner peripheral surface of the workpiece W, and the circumferential position of the lower die restraint wall 25b is set to avoid the entry position of the transport mechanism 30.

Description

[Technical Field]

[0001] The present invention relates to a forging device, a forging die, and a forging method. [Background technology]

[0002] Conventionally, Patent Documents 1 to 4 describe forging dies used for close forging, which include an upper die positioned on the upper side in the direction of gravity and a lower die positioned on the lower side in the direction of gravity.

[0003] In the prior art of Patent Document 1, the lower mold is a combination of a disk-shaped inner mold and an annular outer mold located on the outer periphery of the inner mold. The annular outer mold is integrally provided in the circumferential direction. The annular outer mold restrains the side of the material when it is molded between the upper and lower molds.

[0004] In the prior art of Patent Document 2, the upper mold comprises an inner divided mold that forms the upper surface of the product and an outer divided mold that forms the outer peripheral surface of the product. The outer divided mold is integrally provided in the circumferential direction. The outer divided mold restrains the side surface of the product when the product is molded between the upper and lower molds.

[0005] Patent Document 3 describes a forging die for forming a cross groove joint, used in automobile propeller shafts and the like, as a forged product, which includes an outer ring having V-shaped track grooves in which adjacent track grooves are formed so as to be inclined in different directions in the circumferential direction of the inner peripheral surface.With this type of forging die, the track groove shape of the forged product is inclined in the circumferential direction of the inner peripheral surface, so the product cannot be removed from the forging die using a normal forging method.

[0006] In the prior art of Patent Document 3, among the dies used to forge an outer ring including track grooves, the inner peripheral surface-forming die that forms the inner peripheral surface of the outer ring is configured as being divided into an upper die that forms the inner peripheral surface, including the upwardly inclined surfaces of the track grooves of the outer ring, and a lower die that forms the inner peripheral surface, including the downwardly inclined surfaces of the track grooves, and the divided upper and lower dies are brought together from above and below to form the inner peripheral surface of the outer ring. In this case, the upper die is provided with three fan-shaped blocks spaced equally apart in the circumferential direction for simultaneously forging two adjacent track grooves in a V-shape, while the lower die is provided with three fan-shaped blocks spaced equally apart in the circumferential direction for simultaneously forging two adjacent track grooves in an inverted V-shape. When the upper and lower dies are brought together, the blades that form the upwardly inclined surfaces of the track grooves and the blades that form the downwardly inclined surfaces of the track grooves are integrated to form the blades that form the inclined track grooves. The mating surfaces of the blades that form the upwardly inclined surfaces of the track grooves and the blades that form the downwardly inclined surfaces of the track grooves are formed vertically so that the upper and lower molds can be pulled apart vertically. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-254078 [Patent Document 2] Japanese Patent Application Publication No. 2018-192484 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-317823 Summary of the Invention [Problem to be solved by the invention]

[0008] In all of the prior arts disclosed in Patent Documents 1 to 3, it is not easy to transport a workpiece relative to a forging die. In the prior art of Patent Document 1, an annular outer die is integrally provided in the circumferential direction with the lower die, so when loading a workpiece into the lower die, it is necessary to avoid the annular outer die. Specifically, the workpiece cannot be placed directly on the lower die, and must be dropped onto the lower die from above the annular outer die. This reduces the accuracy of the workpiece placement position relative to the lower die, making it more likely that uneven thickness will occur in the workpiece after forging.

[0009] In the conventional technology of Patent Document 2, an outer split die that restrains the side of the workpiece during molding is provided on the upper die, while the lower die does not restrain the side of the workpiece. In other words, in the conventional technology of Patent Document 2, the horizontal position of the workpiece relative to the lower die is not restrained. Therefore, when a knockout pin is used to push a workpiece stuck to the lower die from below to remove it from the lower die after molding, the workpiece tends to move around when removed from the lower die, causing the horizontal position of the workpiece relative to the lower die to easily shift. This makes it more likely that the workpiece will not be properly gripped when being removed from the lower die.

[0010] In the prior art of Patent Document 3, the inner peripheral surface forming die that forms the inner peripheral surface of the outer ring is configured as being divided into an upper die and a lower die, but there is no mention whatsoever of how the workpiece is transported relative to the forging die.

[0011] The present invention has been made in view of the above background, and aims to provide a forging device, a forging die, and a forging method that allow easy transport of a workpiece. [Means for solving the problem]

[0012] A first aspect of the present invention is a forging die for performing closed forging on the workpiece; a transport mechanism for transporting the workpiece relative to the forging die, The forging die has an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity, The upper mold has an upper mold restraint wall formed thereon that restrains at least one of an outer peripheral surface and an inner peripheral surface of the workpiece, The lower mold has a lower mold restraint wall formed thereon that restrains at least one of an outer peripheral surface and an inner peripheral surface of the workpiece, the upper mold restraint wall and the lower mold restraint wall are formed as a whole around the entire periphery of at least one of the outer periphery and the inner periphery of the workpiece, The lower die restraint wall is disposed in a circumferential position in the forging device so as to avoid the entry position of the transport mechanism.

[0013] A second aspect of the present invention is A forging die for performing closed forging on a workpiece, an upper mold disposed above in the direction of gravity; a lower mold disposed on the lower side in the direction of gravity, An upper mold restraint wall that restrains a part of the outer peripheral surface of the workpiece is formed in the upper mold, The lower mold has a lower mold restraint wall formed thereon that restrains the remaining portion of the outer peripheral surface of the workpiece, The upper die restraint wall and the lower die restraint wall are in a forging die that are formed as a whole around the entire outer periphery of the workpiece.

[0014] A third aspect of the present invention is A forging method using a forging die that performs closed forging on a workpiece and a transport mechanism that transports the workpiece to the forging die, The forging die used has an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity, The upper mold is formed with an upper mold restraint wall that restrains at least one of the outer peripheral surface and the inner peripheral surface of the workpiece, The lower mold is formed with a lower mold restraint wall that restrains at least one of the outer peripheral surface and the inner peripheral surface of the workpiece, The upper mold restraint wall and the lower mold restraint wall are formed as a whole over the entire periphery of at least one of the outer periphery and the inner periphery of the workpiece, The lower mold restraint wall is disposed at a position in the circumferential direction that avoids an entry position of the transport mechanism, a carrying-in process in which the workpiece is gripped by the transport mechanism and transported upward in the direction of gravity of the lower mold, the transport mechanism descends to enter a circumferential gap of the lower mold restraint wall, and the workpiece is placed on the lower mold by releasing the grip of the workpiece by the transport mechanism; a forging process that is carried out after the carrying-in process, in which the upper die and the lower die are closed to forge the workpiece, and the upper die and the lower die are opened; and a carrying-out process, which is carried out after the forging process, in which the transport mechanism enters the circumferential gap in the lower mold restraint wall to grasp the workpiece, and the transport mechanism rises to carry the workpiece out of the lower mold. [Effects of the Invention]

[0015] According to the first aspect of the present invention, the restraint wall is formed separately into an upper mold and a lower mold, and the lower mold restraint wall is arranged to avoid the entry position of the conveying mechanism, thereby improving the accuracy of the workpiece placement position relative to the lower mold when the workpiece is loaded, and suppressing the workpiece from shifting out of position relative to the conveying mechanism when the workpiece is unloaded.

[0016] According to the second aspect of the present invention, the constraint wall is formed separately for the upper mold and the lower mold, so that the lower mold constraint wall can be provided while avoiding interference with the transport mechanism. Therefore, it is possible to improve the accuracy of the position of the workpiece relative to the lower mold when the workpiece is loaded, and to suppress positional deviation of the workpiece relative to the transport mechanism when the workpiece is unloaded.

[0017] According to the third aspect of the present invention, in the carrying-in step, the transport mechanism releases its grip on the workpiece when it has entered the circumferential gap of the lower mold restraint wall, which improves the accuracy of the positioning of the workpiece relative to the lower mold when carrying it in, compared to when the transport mechanism releases its grip on the workpiece above the lower mold restraint wall and drops the workpiece onto the lower mold. Also, in the carrying-out step, the transport mechanism can grip the workpiece while the lower mold restraint wall is restraining the workpiece, which reduces positional deviation of the workpiece relative to the transport mechanism when carrying it out.

[0018] Therefore, according to the first to third aspects of the present invention, it is possible to provide a forging device that allows easy transport of a workpiece to a forging die. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a front view showing the overall configuration of the forging device. [Figure 2] FIG. 3 is a plan view showing the lower die and the transfer mechanism of the forging device. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 10 is a cross-sectional view of the lower mold restraint wall and the upper mold restraint wall when the lower mold and the upper mold are in a closed state. [Figure 6] Cross-sectional view taken along the line VI-VI in Figure 5. [Figure 7] 10A and 10B are cross-sectional views illustrating the workpiece loading operation in the loading step. [Figure 8] 10A and 10B are cross-sectional views illustrating the workpiece carrying-out operation in the carrying-out process. DETAILED DESCRIPTION OF THE INVENTION

[0020] The forging device comprises a forging die that performs sealed forging on a workpiece, and a transport mechanism that transports the workpiece to the forging die. The forging die has an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity. The upper die has an upper die restraint wall that restrains at least one of the outer peripheral surface and inner peripheral surface of the workpiece, and the lower die has a lower die restraint wall that restrains at least one of the outer peripheral surface and inner peripheral surface of the workpiece. The upper die restraint wall and the lower die restraint wall are formed as a whole around the entire circumference of at least one of the outer peripheral surface and inner peripheral surface of the workpiece, and the circumferential position of the lower die restraint wall is set to avoid the entry position of the transport mechanism.

[0021] In the forging device, the transport mechanism may be a transfer-type transport mechanism that grips the workpiece and transports the workpiece into and out of the lower die, thereby providing a forging device that allows easy transport of the workpiece by the transfer-type transport mechanism.

[0022] In the forging apparatus, a plurality of upper and lower die restraint walls may be provided, and the plurality of upper and lower die restraint walls may be formed in the shape of concentric arcs with equal inclination angles. Since the restraint force for restraining the workpiece can be distributed as evenly as possible to the upper and lower die restraint walls, it is easy to provide the upper and lower die restraint walls with the strength to withstand the restraint force.

[0023] In the forging apparatus, a plurality of upper die restraint walls and a plurality of lower die restraint walls may be provided at positions facing each other, making it easier for the transfer type transport mechanism to grip the workpiece.

[0024] In the forging device, the upper die restraint wall and the lower die restraint wall may be provided in pairs, which makes it easier for the transfer type transport mechanism to grip the workpiece.

[0025] In the forging device, the lower die may have a lower die bottom surface portion on which the workpiece is placed, and a knockout pin that pushes the workpiece from below in the direction of gravity toward above in the direction of gravity so that the forged workpiece is released from the lower die bottom surface portion. When the workpiece is released from the lower die bottom surface portion with the knockout pin, the lower die restraint wall can prevent the workpiece from shifting in its horizontal position relative to the lower die, making it easy to grasp the workpiece released from the lower die bottom surface portion with a transport mechanism.

[0026] The forging die is a forging die that performs sealed forging on a workpiece, and comprises an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity, the upper die having an upper die restraint wall formed thereon that restrains a portion of the outer peripheral surface of the workpiece, and the lower die having a lower die restraint wall formed thereon that restrains the remaining portion of the outer peripheral surface of the workpiece, and the upper die restraint wall and the lower die restraint wall are formed as a whole around the entire outer peripheral surface of the workpiece.

[0027] The forging method uses a forging die that performs closed forging on a workpiece and a transport mechanism that transports the workpiece relative to the forging die, and the forging die has an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity, the upper die has an upper die constraint wall formed thereon that constrains at least one of the outer peripheral surface and the inner peripheral surface of the workpiece, and the lower die has a lower die constraint wall formed thereon that constrains at least one of the outer peripheral surface and the inner peripheral surface of the workpiece, and the upper die constraint wall and the lower die constraint wall are formed as a whole around at least one of the outer peripheral surface and the inner peripheral surface of the workpiece. a lower mold restraint wall whose circumferential position is set to avoid the entry position of the transport mechanism; a carrying-in process in which the transport mechanism grips the workpiece and transports it upward in the direction of gravity of the lower mold, the transport mechanism descends and enters the circumferential gap in the lower mold restraint wall, and then releases the grip of the workpiece by the transport mechanism to place it on the lower mold; a forging process that is carried out after the carrying-in process, in which the upper and lower molds are closed to forge the workpiece and the upper and lower molds are opened; and a carrying-out process that is carried out after the forging process, in which the transport mechanism enters the circumferential gap in the lower mold restraint wall to grip the workpiece, and the transport mechanism rises to carry the workpiece out of the lower mold.

[0028] In the forging method, the lower die may include a lower die bottom portion on which the workpiece is placed and a knockout pin that pushes the workpiece from below in the direction of gravity toward above in the direction of gravity so that the forged workpiece is released from the lower die bottom portion, and in the carrying-out step, the knockout pin removes the workpiece from the lower die bottom portion, and the transport mechanism enters a circumferential gap in the lower die restraint wall to grip the workpiece while the workpiece removed from the lower die bottom portion is restrained by the lower die restraint wall. Because the workpiece removed from the lower die bottom portion is gripped by the transport mechanism while restrained by the lower die restraint wall, the workpiece removed from the lower die bottom portion can be reliably gripped by the transport mechanism.

[0029] (Embodiment) 1. Overall configuration of the forging equipment The overall configuration of a forging device 100 of this embodiment will be described with reference to Figs. 1 and 2. The forging device 100 forms a disk-shaped product by hot forging in multiple steps. In this example, the forging device 100 forms a gear blank. The gear blank is an intermediate product formed in the process of forming a gear, and gears are formed by cutting the gear blank.

[0030] The forging device 100 includes a forging die consisting of a lower die 25 and an upper die 27, a transfer-type conveying mechanism 30, and a control device 31. The forging die consisting of the lower die 25 and the upper die 27 forms an enclosed forming space, and performs enclosed forging on the workpiece. Enclosed forging is a method in which the lower die 25 and the upper die 27 are tightly closed when the workpiece has been pressed through, thereby forging the workpiece in an enclosed state.

[0031] The forging device 100 includes a bed 21, a pair of left and right columns 22, a crown 23, a bolster 24, and a slide 26. The column 22 is a columnar member supported by the bed 21. The crown 23 fixes the upper part of the column 22. The bolster 24 is fixed to the upper surface of the bed 21. The slide 26 is supported by the column 22 so that it can move up and down. The lower die 25 is detachably attached to the upper surface of the bolster 24. The upper die 27 is detachably attached to the lower surface of the slide 26.

[0032] The lower die 25 and the upper die 27 are configured to sequentially perform a plurality of forging processes for forming a gear blank, which is a workpiece. In the forging processes, the upper die 27 descends and ascends relative to the fixed lower die 25.

[0033] Forging apparatus 100 includes a carry-in station 28 and an unloading station 29. Carry-in station 28 is located on the upper surface of bolster 24, on the carry-in side of lower die 25 (to the right in FIGS. 1 and 2). A workpiece that has been carried into forging apparatus 100 is placed in carry-in station 28, which is used as a preparation position for transporting the workpiece to an initial forging stage (process). Carry-out station 29 is located on the upper surface of bolster 24, on the carry-out side of lower die 25 (to the left in FIGS. 1 and 2). A workpiece W that has been processed in the final forging stage (process) is placed in carry-out station 29.

[0034] The transport mechanism 30 grips the workpiece positioned at each forging stage (process) in the lower die 25 and the upper die 27 and transports it to the next forging stage (process). The control device 31 controls the elevation of the slide 26 and the operation of the transport mechanism 30.

[0035] 2. Overall configuration of the transport mechanism 30 The overall configuration of the transfer type transport mechanism 30 will be described with reference to Figures 1 and 2. The transport mechanism 30 includes a first feed bar 51, a second feed bar 52, a first finger 53, a second finger 54, and a drive device 55.

[0036] The first feed bar 51 and the second feed bar 52 are arranged to extend in the workpiece conveying direction and to sandwich the lower mold 25 in a direction perpendicular to the conveying direction. The first feed bar 51 and the second feed bar 52 are configured to be movable in the conveying direction (X), the gripping / non-gripping direction (Y), and the lifting direction (Z).

[0037] The first feed bar 51 is provided with a plurality of first fingers 53, which are arranged in the conveying direction. In this example, the first feed bar 51 is provided with five first fingers 53. Each of the first fingers 53 is formed in a shape that allows it to press one end of the workpiece W present at the corresponding forging stage (process). Therefore, each of the first fingers 53 is formed in a shape that corresponds to the shape of the workpiece W at the corresponding forging stage (process).

[0038] The second feed bar 52 is provided with a plurality of second fingers 54, which are arranged in the conveying direction. In this example, the second feed bar 52 is provided with five second fingers 54. Each of the second fingers 54 is formed in a shape that allows it to press one end of the workpiece W present at the corresponding forging stage (process). Therefore, each of the second fingers 54 is formed in a shape that corresponds to the shape of the workpiece W at the corresponding forging stage (process).

[0039] That is, the first finger 53 and the second finger 54 hold the workpiece W by sandwiching it from both sides. With the workpiece W held by the first finger 53 and the second finger 54, the first feed bar 51 and the second feed bar 52 can be moved to transport the workpiece W to the position of the next forging stage (process).

[0040] Drive devices 55 are provided on both ends of first feed bar 51 and second feed bar 52. Drive devices 55 are configured to synchronously move first feed bar 51 and second feed bar 52 in the conveying direction (X), the gripping / non-gripping direction (Y), and the lifting direction (Z).

[0041] The first feed bar 51 and the second feed bar 52 operate in the following order: "gripping (approaching each other) → rising → moving forward in the conveying direction → lowering → not gripping (moving away from each other) → returning in the opposite direction to the conveying direction," and repeat this operation. This operation is a so-called three-dimensional transfer transport operation. By this operation, a workpiece W present at a predetermined forging stage (process) position is transported to the position of the next forging stage (process). At this time, multiple workpieces W can be transported simultaneously.

[0042] 3. Overall structure of forging die 3 shows a portion of a lower die 25 constituting one forging process among a plurality of forging processes. The lower die 25 has a lower die bottom surface portion 25a, a lower die restraining wall 25b, and a knockout pin 25c. The lower die bottom surface portion 25a constitutes the portion of the forging die that forms the bottom surface of the workpiece W. The lower die restraining wall 25b restrains a portion of the outer peripheral surface of the workpiece W when performing closed-circuit forging on the workpiece W. The knockout pin 25c pushes the bottom surface of the workpiece W after closed-circuit forging from the lower side in the direction of gravity toward the upper side in the direction of gravity, thereby releasing the workpiece W after closed-circuit forging from the lower die 25.

[0043] The lower mold restraint wall 25b is divided into a plurality of pieces (two in the example of FIG. 3) in the circumferential direction of the workpiece W, and a lower mold notch 25d is formed between the lower mold restraint walls 25b.

[0044] 4 shows a portion of an upper die 27 that constitutes one of a plurality of forging processes. The upper die 27 has an upper die upper surface portion 27a and an upper die restraining wall 27b. The upper die upper surface portion 27a constitutes the portion of the forging die that forms the upper surface of the workpiece W. The upper die restraining wall 27b restrains a portion of the outer peripheral surface of the workpiece W when the workpiece W is subjected to closed-circuit forging.

[0045] The upper mold restraint wall 27b is divided into a plurality of pieces (two in the example of FIG. 4) in the circumferential direction of the workpiece W, and upper mold notches 27c are formed between the upper mold restraint walls 27b.

[0046] Upper die cutout 27c is formed corresponding to lower die constraint wall 25b of lower die 25, and lower die constraint wall 25b fits into upper die cutout 27c of upper die 27. Similarly, lower die cutout 25d of lower die 25 is formed corresponding to upper die constraint wall 27b of upper die 27, and upper die constraint wall 27b of upper die 27 fits into lower die cutout 25d of lower die 25. As a result, lower die constraint wall 25b and upper die constraint wall 27b are formed as a whole around the entire outer periphery of the workpiece.

[0047] Fig. 5 is a cross-sectional view of the lower mold restraint wall 25b and the upper mold restraint wall 27b cut in a horizontal plane (the XY plane in Figs. 1 to 5) when the lower mold 25 shown in Fig. 3 and the upper mold 27 shown in Fig. 4 are closed. Fig. 6 is a cross-sectional view taken along the line VI-VI in Fig. 5. The lower mold restraint wall 25b and the upper mold restraint wall 27b are formed over the entire outer periphery of the workpiece. A sealed forming space C is formed inside the closed lower mold 25 and upper mold 27. The workpiece is subjected to sealed forging in the sealed forming space C.

[0048] The lower mold restraint wall 25b and the upper mold restraint wall 27b constitute restraint walls that restrain the outer peripheral surface of the workpiece over the entire periphery when the workpiece is subjected to closed-circumferential forging. The lower mold restraint wall 25b and the upper mold restraint wall 27b constitute the portion of the forging die that forms the side surface of the workpiece.

[0049] A plurality of lower mold constraint walls 25b and a plurality of upper mold constraint walls 27b are provided. In this example, a pair of lower mold constraint walls 25b and a pair of upper mold constraint walls 27b are provided (i.e., two of each). The plurality of lower mold constraint walls 25b and the plurality of upper mold constraint walls 27b are formed in the shape of concentric arcs. In this example, the circumferential angle θL of the end of the plurality of lower mold constraint walls 25b on the work side (toward the center of the arc in this example) and the circumferential angle θU of the end of the plurality of upper mold constraint walls 27b on the work side (toward the center of the arc in this example) are both 90° and are equal to each other.

[0050] When the upper mold 27 opens and the first finger 53 and the second finger 54 of the conveying mechanism 30 grip a workpiece, the first finger 53 and the second finger 54 move toward the center of the lower mold 25 in the gripping / non-gripping direction (Y) as indicated by the thick solid arrow in FIG. 5 . The lower mold constraint wall 25b is positioned to avoid interference with the first finger 53 and the second finger 54. That is, the circumferential position of the lower mold constraint wall 25b is set to avoid the entry position of the conveying mechanism 30. In this example, the pair of lower mold constraint walls 25b are positioned opposite each other, and the pair of upper mold constraint walls 27b are also positioned opposite each other. Specifically, the pair of lower mold constraint walls 25b are positioned opposite each other in a direction (the conveying direction (X) in this example) perpendicular to the gripping / non-gripping direction (Y), and the pair of upper mold constraint walls 27b are positioned opposite each other in the gripping / non-gripping direction (Y).

[0051] 4. Forging method using forging equipment The forging method using the forging device 100 of this embodiment includes a carrying-in step, a forging step, and a carrying-out step.

[0052] In the carry-in process, the conveying mechanism 30 performs the three-dimensional transfer conveying operation described above to grasp the workpiece W at the position of the previous forging stage (process) and carry it into the adjacent forging stage (process). As a result, the workpiece W is set in the lower die 25.

[0053] 7 is a diagram illustrating the loading operation of the workpiece W in the loading step. In the loading step, the first finger 53 and the second finger 54 of the transport mechanism 30 grip the workpiece W and transport it upward in the direction of gravity of the lower mold 25, and the first finger 53 and the second finger 54 descend to enter the lower mold notch 25d (i.e., the circumferential gap of the lower mold restraint wall 25b).

[0054] Because the lower mold restraint wall 25b is positioned to avoid the area where the first finger 53 and the second finger 54 descend, the first finger 53 and the second finger 54 do not interfere with the lower mold restraint wall 25b when descending. Therefore, the first finger 53 and the second finger 54 can be lowered until the workpiece W abuts against the lower mold bottom surface 25a. Then, the first finger 53 and the second finger 54 release their grip on the workpiece W when the workpiece W abuts against the lower mold bottom surface 25a. This prevents the workpiece W from shifting in position relative to the lower mold 25 and improper setting. In other words, this prevents the workpiece W from shifting in position relative to the lower mold 25 and improper setting compared to when the first finger 53 and the second finger 54 release their grip on the workpiece W before the workpiece W abuts against the lower mold bottom surface 25a and the workpiece W is dropped from above the lower mold bottom surface 25a.

[0055] In the forging process that is carried out after the carrying-in process, the upper die 27 descends and then ascends relative to the fixed lower die 25. As a result, the workpiece W is sealed in the sealed space C shown in Fig. 6 and subjected to sealed forging. Once the upper die 27 ascends, as shown in Fig. 8, the knockout pin 25c in the lower die 25 pushes the bottom surface of the workpiece W from the lower side in the direction of gravity toward the upper side in the direction of gravity, thereby releasing the workpiece W after sealed forging from the bottom surface portion 25a of the lower die.

[0056] The workpiece W released from the lower mold bottom surface portion 25a by the knockout pin 25c has its radial position restrained by the lower mold restraint wall 25b, so that radial displacement of the workpiece W relative to the lower mold 25 can be prevented when the workpiece W is released from the lower mold bottom surface portion 25a by the knockout pin 25c.

[0057] In the carry-out process that is performed after the forging process, the transport mechanism 30 performs the above-mentioned three-dimensional transfer transport operation to grasp the workpiece W at the position of the current forging stage (process) and transport it to the next forging stage (process). The carry-out process is also the carry-in process in the next forging stage (process).

[0058] In the unloading process, as shown in Figure 8, the first finger 53 and the second finger 54 of the conveying mechanism 30 enter the lower mold cutout portion 25d (i.e., the circumferential gap of the lower mold restraint wall 25b) and grasp the workpiece W that has been released from the lower mold bottom portion 25a by the knockout pin 25c, and then the first finger 53 and the second finger 54 rise to unload the workpiece W from the lower mold 25.

[0059] In the carrying-out process, the first finger 53 and the second finger 54 grip the workpiece W while the workpiece W is constrained in the radial direction by the lower mold restraint wall 25b, and therefore it is possible to prevent the workpiece W from being displaced in the radial direction relative to the first finger 53 and the second finger 54. Therefore, the workpiece W can be reliably gripped by the first finger 53 and the second finger 54.

[0060] 5.Effects In this embodiment, the lower mold restraint wall 25b and the upper mold restraint wall 27b are formed as a whole around the entire circumference of at least one of the outer and inner surfaces of the workpiece W, and the circumferential position of the lower mold restraint wall is set to avoid the entry position of the conveying mechanism 30.

[0061] As a result, the restraint wall is divided into a lower mold restraint wall 25b on the lower mold 25 side and an upper mold restraint wall 27b on the upper mold 27 side, and the lower mold restraint wall 25b is arranged to avoid the entry position of the first finger 53 and the second finger 54 of the conveying mechanism 30, thereby improving the accuracy of the placement position of the workpiece W relative to the lower mold 25 when the workpiece W is transported, and suppressing the workpiece from shifting in position relative to the conveying mechanism when the workpiece W is transported out.

[0062] That is, if the constraint wall is provided only on the lower mold side, or if the lower mold constraint wall 25b is provided in a location that interferes with the first finger 53 and the second finger 54, the workpiece W must be released from its grip by the first finger 53 and the second finger 54 while it is floating above the lower mold bottom surface 25a before it comes into contact with the lower mold bottom surface 25a. In this case, the workpiece W will fall from above the lower mold bottom surface 25a, which makes it more likely that the workpiece W will be misaligned with respect to the lower mold 25 and will not be properly set.

[0063] In contrast, in this embodiment, the lower mold restraint wall 25b is arranged to avoid the entry position of the first finger 53 and the second finger 54 of the conveying mechanism 30, thereby improving the accuracy of the placement position of the workpiece W relative to the lower mold 25 when the workpiece W is transported in.

[0064] Furthermore, if the restraining wall is provided only on the upper die 27 side and not on the lower die 25 side, the radial position of the workpiece W cannot be restrained when the forged workpiece W is released from the bottom surface portion 25a of the lower die by the knockout pin 25c, which makes it more likely that the first finger 53 and the second finger 54 will not be able to properly grip the workpiece W when transporting it out.

[0065] In contrast to this, in this embodiment, the lower die restraint wall 25b is provided on the lower die 25, so that when the forged workpiece W is released from the lower die bottom surface portion 25a by the knockout pin 25c, the radial position of the workpiece W can be restrained by the lower die restraint wall 25b. Therefore, the workpiece W can be securely gripped by the first finger 53 and the second finger 54 when the workpiece W is carried out.

[0066] In this way, according to this embodiment, the transfer of the workpiece W by the transfer type transport mechanism 30 can be facilitated.

[0067] In this embodiment, a plurality of lower mold constraint walls 25b and a plurality of upper mold constraint walls 27b are provided, and the plurality of lower mold constraint walls 25b and the plurality of upper mold constraint walls 27b are formed in the shape of concentric arcs with equal circumferential angles. This allows the constraint force that constrains the workpiece W to be distributed as evenly as possible to the lower mold constraint walls 25b and the upper mold constraint walls 27b, making it easy to provide the lower mold constraint walls 25b and the upper mold constraint walls 27b with the strength to withstand the constraint force.

[0068] In this embodiment, two lower mold restraint walls 25b and two upper mold restraint walls 27b are provided at positions facing each other, so that it is easy to provide the lower mold restraint walls 25b so as to avoid the entry positions of the first finger 53 and the second finger 54 of the transport mechanism 30. Therefore, it becomes easy for the transport mechanism 30 to grip the workpiece W.

[0069] In this embodiment, a pair of lower mold restraint walls 25b and a pair of upper mold restraint walls 27b are provided, so that it is easy to provide the lower mold restraint walls 25b so as to avoid the entry positions of the first finger 53 and the second finger 54 of the transport mechanism 30. Therefore, it becomes easy for the transport mechanism 30 to grip the workpiece W.

[0070] In this embodiment, when the workpiece W is removed from the lower mold bottom surface portion 25a by the knockout pin 25c of the lower mold 25, the lower mold restraint wall 25b can prevent the workpiece from shifting in its horizontal position relative to the lower mold 25, making it easier for the conveying mechanism 30 to grasp the workpiece W that has been removed from the lower mold bottom surface portion 25a.

[0071] In this embodiment, in the carrying-in step, the first finger 53 and the second finger 54 of the transport mechanism 30 grip the workpiece W and transport it upward in the direction of gravity of the lower mold 25, the first finger 53 and the second finger 54 of the transport mechanism 30 descend and enter the circumferential gap of the lower mold restraint wall 25b, and then the first finger 53 and the second finger 54 of the transport mechanism 30 release their grip on the workpiece W, thereby placing the workpiece W on the lower mold bottom surface portion 25a. This improves the accuracy of the position of the workpiece W relative to the lower mold bottom surface portion 25a when carrying in the workpiece W, compared to when the first finger 53 and the second finger 54 of the transport mechanism 30 release their grip on the workpiece W above the lower mold restraint wall 25b and drop the workpiece W onto the lower mold bottom surface portion 25a.

[0072] In this embodiment, in the carrying-out step, the first finger 53 and the second finger 54 of the transport mechanism 30 enter the circumferential gap in the lower mold restraint wall 25b to grip the workpiece W, and the first finger 53 and the second finger 54 of the transport mechanism 30 rise to carry the workpiece W out of the lower mold 25. This allows the first finger 53 and the second finger 54 of the transport mechanism 30 to grip the workpiece W while the lower mold restraint wall 25b is restraining the workpiece W, thereby preventing the workpiece W from shifting in position relative to the transport mechanism 30 when the workpiece W is carried out.

[0073] In this embodiment, in the carrying-out step, the knockout pin 25c removes the workpiece W from the lower mold bottom surface portion 25a, and while the workpiece W removed from the lower mold bottom surface portion 25a is constrained by the lower mold constraint wall 25b, the first finger 53 and the second finger 54 of the transport mechanism 30 enter the circumferential gap of the lower mold constraint wall 25b to grip the workpiece W. According to this, the workpiece W removed from the lower mold bottom surface portion 25a by the knockout pin 25c is gripped by the first finger 53 and the second finger 54 of the transport mechanism 30 while being constrained by the lower mold constraint wall 25b, so that the workpiece W removed from the lower mold bottom surface portion 25a can be reliably gripped by the first finger 53 and the second finger 54 of the transport mechanism 30.

[0074] (Other embodiments) (1) In the above embodiment, the lower mold restraint wall 25b and the upper mold restraint wall 27b restrain the outer peripheral surface of the workpiece W, but the lower mold restraint wall 25b and the upper mold restraint wall 27b may also restrain the inner peripheral surface of the workpiece W.

[0075] (2) The number and arrangement of the lower mold restraint walls 25b and the upper mold restraint walls 27b are not limited to those in the above embodiment, and the number and arrangement of the lower mold restraint walls 25b and the upper mold restraint walls 27b can be changed as appropriate as long as the fingers of the transport mechanism 30 can enter the circumferential gaps of the lower mold restraint walls 25b. Furthermore, the number and arrangement of the fingers of the transport mechanism 30 are not limited to those in the above embodiment, and the number and arrangement of the fingers of the transport mechanism 30 can be changed as appropriate as long as they can grip the workpiece W.

[0076] For example, in the above embodiment, the circumferential angle of each lower mold restraint wall 25b and the circumferential angle of each upper mold restraint wall 27b are equal to each other, but the circumferential angle of each lower mold restraint wall 25b and the circumferential angle of each upper mold restraint wall 27b may be different from each other.

[0077] For example, in the above embodiment, two lower mold restraint walls 25b and two upper mold restraint walls 27b are provided (in other words, one pair of each), but the number of each of the lower mold restraint walls 25b and the upper mold restraint walls 27b may be three or more.

[0078] For example, in this embodiment, the lower mold restraint wall 25b and the upper mold restraint wall 27b are arranged in positions facing each other, but depending on the number and arrangement of the fingers of the conveying mechanism 30, the lower mold restraint wall 25b and the upper mold restraint wall 27b may be arranged in positions that do not face each other.

[0079] Furthermore, the structure of the transport mechanism 30 is not limited to that provided with the first feed bar 51 and the second feed bar 52 as in the above embodiment, and the structure of the transport mechanism 30 can be modified as appropriate as long as it is capable of transporting the workpiece W. For example, the transport mechanism 30 may be one provided with an articulated robot (multi-axis robot).

[0080] (3) In the above embodiment, the forging device 100 is configured to sequentially perform multiple forging processes to form the workpiece W, but the forging device 100 may also be configured to perform only one forging process.

[0081] (4) In the above embodiment, the product formed by the forging device 100 is a gear blank. However, the forging device 100 can form various types of products. [Explanation of symbols]

[0082] 25 Lower mold 25a Lower mold bottom part 25b Lower mold restraint wall 25c knockout pin 27 Upper mold 27b Upper mold restraint wall 30 Conveying mechanism double work

Claims

1. a forging die for performing closed forging on the workpiece; a transport mechanism for transporting the workpiece relative to the forging die, The forging die has an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity, The upper mold has an upper mold restraint wall formed thereon that restrains at least one of an outer peripheral surface and an inner peripheral surface of the workpiece, The lower mold has a lower mold restraint wall formed thereon that restrains at least one of an outer peripheral surface and an inner peripheral surface of the workpiece, the upper mold restraint wall and the lower mold restraint wall are formed as a whole around the entire periphery of at least one of the outer periphery and the inner periphery of the workpiece, A forging device, wherein the lower die restraint wall is positioned in a circumferential direction so as to avoid an entry position of the transport mechanism.

2. 2. The forging device according to claim 1, wherein the transport mechanism is a transfer type transport mechanism that grips the workpiece and transports the workpiece into and out of the lower die.

3. a plurality of upper mold restraint walls and a plurality of lower mold restraint walls are provided, 3. The forging device according to claim 1, wherein the plurality of upper die restraint walls and the plurality of lower die restraint walls are formed in the shape of arcs that are concentric with each other and have equal circumferential angles.

4. 3. The forging device according to claim 1, wherein a plurality of said upper die restraint walls and a plurality of said lower die restraint walls are provided at positions facing each other.

5. The forging device according to claim 4 , wherein a pair of said upper die restraint walls and a pair of said lower die restraint walls are provided.

6. 2. The forging device according to claim 1, wherein the lower die has a bottom surface on which the workpiece is placed, and a knockout pin that pushes the workpiece from a lower side in the direction of gravity toward an upper side in the direction of gravity so that the workpiece is released from the bottom surface of the lower die after forging.

7. A forging die for performing closed forging on a workpiece, an upper mold disposed above in the direction of gravity; a lower mold disposed on the lower side in the direction of gravity, An upper mold restraint wall that restrains a part of the outer peripheral surface of the workpiece is formed in the upper mold, The lower mold has a lower mold restraint wall formed thereon that restrains the remaining portion of the outer peripheral surface of the workpiece, A forging die, wherein the upper die restraint wall and the lower die restraint wall are formed as a whole around the entire outer periphery of the workpiece.

8. A forging method using a forging die that performs closed forging on a workpiece and a transport mechanism that transports the workpiece to the forging die, The forging die used has an upper die arranged on the upper side in the direction of gravity and a lower die arranged on the lower side in the direction of gravity, The upper mold is formed with an upper mold restraint wall that restrains at least one of the outer peripheral surface and the inner peripheral surface of the workpiece, The lower mold is formed with a lower mold restraint wall that restrains at least one of the outer peripheral surface and the inner peripheral surface of the workpiece, The upper mold restraint wall and the lower mold restraint wall are formed as a whole over the entire periphery of at least one of the outer periphery and the inner periphery of the workpiece, The lower mold restraint wall is disposed at a position in the circumferential direction that avoids an entry position of the transport mechanism, a carrying-in process in which the workpiece is gripped by the transport mechanism and transported upward in the direction of gravity of the lower mold, the transport mechanism descends to enter a circumferential gap of the lower mold restraint wall, and the workpiece is placed on the lower mold by releasing the grip of the workpiece by the transport mechanism; a forging process that is carried out after the carrying-in process, in which the upper die and the lower die are closed to forge the workpiece, and the upper die and the lower die are opened; a carrying-out process, which is carried out after the forging process, in which the transport mechanism enters the circumferential gap of the lower die restraint wall to grip the workpiece, and the transport mechanism rises to carry the workpiece out of the lower die.

9. The lower die has a bottom surface portion on which the workpiece is placed, and a knockout pin that pushes the workpiece from a lower side in the direction of gravity toward an upper side in the direction of gravity so that the workpiece after forging is released from the bottom surface portion of the lower die, 9. The forging method according to claim 8, wherein in the carrying-out process, the knockout pin removes the workpiece from the bottom surface of the lower die, and the transport mechanism enters a circumferential gap in the lower die restraint wall to grasp the workpiece while the workpiece removed from the bottom surface of the lower die is restrained by the lower die restraint wall.

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