Forging press device and forged product manufacturing method

Abstract

To provide a forging press device that can effectively recover scales during press molding even if there is almost no gap between a metal mold and a work-piece as in closed forging, and a forged product manufacturing method with use of the device.SOLUTION: A forging press device 1A performs: a temporary press operation Q1; a return operation Q2 for forming a gap S1 between one metal mold (upper mold 2) and a work-piece W; and a main press operation Q3, and forms a closed space S2 communicating with the gap between a pair of metal molds. One metal mold is provided with an air injection port 15 opening on a molding surface 11 thereof. During the return operation, scales O on a surface of the work-piece are scattered into the closed space by air injected from the air injection port via the gap, and the scattered scales are suctioned and recovered to the exterior from the closed space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a forging press apparatus and a method for manufacturing a forged product, and more particularly to a forging press apparatus that presses a workpiece between a pair of dies that can be moved toward or away from each other, and a method for manufacturing a forged product using the same. [Background technology]

[0002] As a conventional forging press device, one that presses a workpiece between a pair of dies that can move toward and away from each other is generally known (see, for example, Patent Document 1, etc.). Patent Document 1 describes a forging press device that collects scales peeled off from the surface of a workpiece when the rectangular workpiece in side view is pressed so as to be crushed by an upper die and a lower die. More specifically, the forging press device includes an upper die cover and a lower die cover that cover the upper die and the lower die, respectively, an air injection means that supplies air to the inside of the press through the upper die cover, and a negative pressure generating means that generates a negative pressure inside the press through the lower die cover. When the upper die descends near the bottom dead center and the tip portions of the upper die cover and the lower die cover overlap to seal the inside, the air injection means injects air into the inside to generate a spiral airflow, and at the same time, the negative pressure means creates a negative pressure inside, thereby suctioning and collecting the scales from inside the press. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-099722 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, Patent Document 1 describes a case where a rectangular workpiece is pressed by crushing it with an upper die and a lower die, but does not describe a case where a workpiece of other shape is pressed. For example, when a rod-shaped workpiece is pressed by crushing it with an upper die and a lower die, in order to prevent buckling of the rod-shaped workpiece, an upper die having a pressing surface that abuts against the axial end surface of the workpiece and a restraining surface that abuts against the outer peripheral surface of the axial end side of the workpiece is often adopted. When adopting such an upper die, even if an attempt is made to recover the scale by applying the technology of Patent Document 1, since there is almost no gap between the upper die and the workpiece as in closed forging, it is difficult to generate a spiral airflow by air between the upper die and the workpiece, and the scale cannot be recovered.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a forging press device that can effectively recover scale during press forming, even when there is almost no gap between the die and the workpiece, such as in closed forging, and a method for manufacturing forged products using the same. [Means for solving the problem]

[0006] The present invention is as follows. 1. A forging press device that presses a workpiece between a pair of dies that can move toward and away from each other along a moving axis, a temporary pressing operation in which the pair of dies are brought close to each other to temporarily press the workpiece; a return operation for separating the pair of dies from each other so as to release the temporary pressing of the workpiece, thereby forming a gap between one of the pair of dies and the workpiece; A final pressing operation is performed by bringing the pair of dies close to each other and final pressing the workpiece, and A sealed space communicating with the gap is formed between the pair of molds, The one of the dies is provided with an air injection port opening on its molding surface, This forging press device is characterized in that during the returning operation, air is sprayed from the air nozzle through the gap to scatter scale on the surface of the workpiece into the sealed space, and the scattered scale is sucked out of the sealed space and collected to the outside. 2. The molding surface of the one die has a restraint surface where the air injection port opens and which abuts against the outer peripheral surface or the inner peripheral surface of the workpiece; The forging press apparatus according to claim 1, wherein the restraint surface has a tapered portion and / or a curved portion that expands or contracts in diameter as it approaches the other die. 3. A forging press device as described in 2 above, wherein the restraint surface has a curved end portion that is continuous with the end portion of the tapered portion or the curved portion. 4. A forging press device as described in 1 above, wherein one of the dies is provided with a plurality of air injection ports that open at positions offset in the direction of the movement axis on the molding surface. 5. The one die is an upper die and the other die is a lower die; The molding surface of the upper die has a pressing surface that contacts an axial end surface of the upper end of the rod-shaped workpiece, and a restraining surface where the air ejection port opens and contacts an outer peripheral surface of the upper end of the workpiece, The forging press apparatus described in 1. above, wherein the lower die has a holding portion that holds the lower end of the workpiece. 6. A forging press device as described in 1 above, wherein the other die is provided with an air outlet opening into the sealed space. 7. A method for manufacturing a forged product, characterized by using the forging press apparatus described in any one of 1. to 6. above. Effect of the Invention

[0007] According to the present invention, a gap is formed between the die and the workpiece during the return operation, so that scale on the surface of the workpiece is scattered into the sealed space by air injected from the air injection port through the gap, and the scattered scale is sucked and collected from the sealed space to the outside. Therefore, even when there is almost no gap between the die and the workpiece, as in closed forging, scale can be effectively collected during press forming. [Brief description of the drawings]

[0008] The present invention will be further described in the following detailed description by way of non-limiting examples of exemplary embodiments according to the invention and with reference to the several drawings mentioned, in which like reference numerals refer to like elements throughout the several views of the drawings. [Figure 1] 1 is a vertical sectional view of a forging press device according to a first embodiment. [Diagram 2] FIG. 2 is an enlarged view of a main part of FIG. [Diagram 3] FIG. 3 is a view taken along the arrow b in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 2 is an explanatory diagram of the operation of the forging press device, showing a time chart of the preliminary press operation, the return operation, and the main press operation. [Figure 6] 1A and 1B are diagrams for explaining the operation of a forging press device, in which (a) shows the state at the start of forming in a preliminary press operation, and (b) shows the state in which the upper die is located at the bottom dead center in a main press operation. [Figure 7] 10 is an explanatory diagram of the operation of the forging press device, showing the state in which air is injected into the gap during the return operation. FIG. [Figure 8] 1A to 1C are diagrams illustrating the operation of a forging press device, in which (a) shows a workpiece before press forming, (b) shows an intermediate forged product after press forming, and (c) shows a forged product (final product) obtained from the intermediate forged product. [Figure 9] 1A and 1B are explanatory diagrams for explaining modified examples 1 and 2 of a forging press device, in which (a) shows a configuration in which the restraining surface of the upper mold has a curved portion (modified example 1), and (b) shows a configuration in which the restraining surface of the upper mold has a curved portion and a tapered portion (modified example 2). [Figure 10] 5A and 5B are explanatory views for explaining a forging press device according to a second embodiment, in which (a) shows a state before press forming, and (b) shows a state in which air is injected into the gap during a return operation. [Figure 11] FIG. 11 is a vertical sectional view of a forging press device according to a third embodiment. [Figure 12] 12 is a cross-sectional view taken along line XII-XII in FIG. 11. [Figure 13] FIG. 11 is an explanatory view for explaining a scale collection section according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The matters shown herein are illustrative and are intended to exemplify the embodiments of the present invention, and are described for the purpose of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this respect, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description in conjunction with the drawings will make it clear to those skilled in the art how some forms of the present invention can be actually embodied.

[0010] Hereinafter, the present invention will be described in detail with reference to the drawings and embodiments.

[0011] <Embodiment 1> As shown in FIG. 1, the forging press 1A according to the present embodiment presses a workpiece (material) W between an upper die 2 and a lower die 3 that can move toward and away from each other along a moving axis C. The workpiece W before press forming by the forging press 1A is a round bar (see FIG. 8(a)). The intermediate forged product F1 after press forming by the forging press 1A has a shaft portion 51 and a truncated cone portion 52 connected to one end side of the shaft portion 51 (see FIG. 8(b)). The intermediate forged product F1 is subjected to press forming once or twice or more times by one or two or more other forging presses to become a forged product F2 (specifically, a rear shaft). The forged product F2 has a shaft portion 53 and a flange portion 54 provided on one end side of the shaft portion 53 (see FIG. 8(c)). In the present embodiment, a rear shaft is exemplified as the "forged product" according to the present invention, but is not limited thereto, and may be, for example, a drive pinion, an output shaft, a counter gear shaft, or the like.

[0012] The upper die 2 is a movable die and is fixed to a ram 5. The ram 5 is raised and lowered by a drive unit 6. The drive unit 6 has a main hydraulic cylinder 7a and left and right auxiliary hydraulic cylinders 7b, 7b arranged on either side of the main hydraulic cylinder 7a. The main hydraulic cylinder 7a has a larger thrust than each of the auxiliary hydraulic cylinders 7b. The forging press device 1A is configured so that the control unit 9 drives and controls each of the hydraulic cylinders 7a, 7b to perform a preliminary press operation Q1, a return operation Q2, and a main press operation Q3 (i.e., perform press forming in a two-stage motion) (see FIG. 5).

[0013] The provisional press operation Q1 is an operation in which the upper die 2 and the lower die 3 are brought close to each other by lowering the upper die 2, thereby provisionally pressing the workpiece W. The return operation Q2 is an operation in which the upper die 2 and the lower die 3 are separated by raising the upper die 2 (for example, raising by about 10 to 20 mm) so as to release the provisional pressing of the workpiece W, thereby forming a gap S1 (for example, a gap S1 of about 0.4 to 1 mm) between the upper die 2 and the workpiece W (see FIG. 7). The main press operation Q3 is an operation in which the upper die 2 and the lower die 3 are brought close to each other by lowering the upper die 2, thereby finally pressing the workpiece W. In the main press operation Q3, the thrust force applied to the workpiece W is larger than that in the provisional press operation Q1. Specifically, the provisional press operation Q1 is performed by operating the left and right auxiliary cylinders 7b, 7b, and the main press operation Q3 is performed by operating the main cylinder 7a and the left and right auxiliary cylinders 7b, 7b.

[0014] The upper die 2 has a cylindrical die 2a and a central die 2b provided at the center of the upper part of the cylindrical die 2a. The molding surface 11 of the upper die 2 has a pressing surface 12 that abuts against the axial end surface of the upper end of the workpiece W, and a restraining surface (restricting inner peripheral surface) 13 in which an air injection port 15 described later opens and abuts against the outer peripheral surface of the upper end of the workpiece W. The pressing surface 12 is formed by the lower surface of the central die 2b. The restraining surface 13 is formed by the inner peripheral surface of the cylindrical die 2a. The restraining surface 13 has a tapered portion 13a whose diameter increases toward the lower die 3. The restraining surface 13 has a curved end portion 13b that is connected to the lower end portion of the tapered portion 13a. The curved end portion 13b increases in diameter toward the lower die 3, and constitutes the end portion (specifically the lower end portion) of the restraining surface 13 in the direction of the moving axis C.

[0015] As shown in FIGS. 2 and 3, the upper mold 2 is provided with a plurality (two in the figure) of air injection ports 15 that open to the restraint surface 13. Each air injection port 15 is connected to an air supply source 18 (for example, an air compressor, a blower, etc.) via a pipe 17. A valve 19 that is opened and closed by the above control unit 9 is provided in the pipe 17. The control unit 9 opens the valve 19 during the return operation Q2 to supply air from the air supply source 18 to each air injection port 15. Note that the timing of air supply and stop to the air injection port 15 is not particularly limited. For example, the air supply may be performed simultaneously with the start of the return operation Q2, or may be performed after a lapse of a predetermined time t1 (before the end of the return operation) from the start of the return operation Q2. Further, the stop of the air supply may be performed after a lapse of a predetermined time t2 (t1 < t2) from the start of the return operation Q2 (before the end of the return operation), may be performed simultaneously with the end of the return operation Q2, or may be performed after a lapse of a predetermined time from the start of the present press operation Q3. Furthermore, the air supply may be constantly performed during the press forming including each operation Q1 to Q3.

[0016] Each air ejection port 15 opens at a position shifted in the direction of the movement axis C on the restraint surface 13 of the upper mold 2. Specifically, the upper air ejection port 15 opens at the upper end of the restraint surface 13, and the lower air ejection port 15 opens at the middle part of the restraint surface 13 in the vertical direction. The upper air ejection port 15 extends in a direction inclined at an angle (obtuse angle) θ1 with respect to the movement axis C in a side view of the upper mold 2. The lower air ejection port 15 extends in a direction inclined at an angle (obtuse angle) θ2 (θ1<θ2) with respect to the movement axis C in a side view of the upper mold 2. Each air ejection port 15 extends in a tangential direction of a circumference centered on the movement axis C (specifically, a circumference slightly smaller than the inner circumference of the restraint surface 13) in a plan view of the upper mold 2. Furthermore, each air ejection port 15 is arranged at a position that is rotationally symmetric (specifically, 180-degree rotationally symmetric) with respect to the movement axis C. As a result, during the return operation Q2, air is sprayed from the air spray nozzle 15 into the gap S1, generating downward spiral air currents (swirling air currents) H1 and H2 within the gap S1 (see Fig. 7). Note that in Fig. 7, the spiral air current H1 indicates the air current caused by air sprayed from the upper air spray nozzle 15, and the spiral air current H2 indicates the air current caused by air sprayed from the lower air spray nozzle 15.

[0017] Here, the air ejection port 15 is not particularly limited in its extension direction, location, and number, as long as the scale O adhering to the surface of the workpiece W can be scattered into the sealed space S2 by air ejection. For example, two or more air ejection ports 15 extending at the same angle with respect to the movement axis C may be employed. Also, an air ejection port 15 extending in a direction perpendicular to the movement axis C may be employed. Also, an air ejection port 15 extending in a direction inclined to the tangent direction of the circumference centered on the movement axis C may be employed. Furthermore, only one air ejection port 15 may be employed.

[0018] The lower die 3 is a fixed die, and is fixed to the bolster 21 (see FIG. 1). The lower die 3 has a holding part 22 that holds the lower end of the workpiece W. The holding part 22 is formed by the inner peripheral surface of the cylindrical lower die 3 into which the lower end of the workpiece W is pressed. A cylindrical lower die holder 24 that covers the outer peripheral surface of the upper die 2 is provided on the outer peripheral side of the lower die 3. During the preliminary press operation Q1, the inner peripheral surface of the lower die holder 24 and the outer peripheral surface of the upper die 2 overlap each other, so that an enclosed space S2 that communicates with the gap S1 is formed between the upper die 2 and the lower die 3 (specifically, between the inner peripheral surface of the lower die holder 24, the lower surface of the upper die 2, and the upper surface of the lower die 3). The lower die holder 24 is provided with an outlet 25 for discharging the scale O. The outlet 25 opens into the enclosed space S2 and extends in the tangential direction of the circumference centered on the movement axis C (see FIG. 4). Furthermore, the exhaust port 25 is connected to a scale collection section 27 via a duct 26. The scale collection section 27 is connected to an air suction source 28 (e.g., an air ejector, a vacuum pump, etc.) via a duct 29. By operating the air suction source 28, a suction airflow (negative pressure) is applied to the enclosed space S2 via the exhaust port 25 and the duct 26, and the scale O scattered in the enclosed space S2 is sucked and collected by the scale collection section 27.

[0019] In this embodiment, the air suction source 28 is operated constantly during press molding including each of the operations Q1 to Q3. However, the operation of the air suction source 28 may be controlled in accordance with the timing of supplying and stopping air to the air ejection port 15. In addition, in this embodiment, the lower die holder 24 overlapping with the upper die 2 is provided on the lower die 3 to form the sealed space S2, but this is not limited thereto. For example, the upper die 2 may be provided with a cylindrical upper die holder overlapping with the lower die 3 to form the sealed space S2, or the upper die 2 and the lower die 3 may be provided with cylindrical holders overlapping with each other to form the sealed space S2. Furthermore, in this embodiment, the lower die holder 24 is provided with the discharge port 25, but this is not limited thereto. For example, the lower die 3 may be provided with the discharge port 25.

[0020] Next, the effects of the forging press device 1A configured as above will be described. In the preparation state for press molding, the upper die 2 is located at the top dead center, and the holding portion 22 of the lower die 3 holds the workpiece W heated to a high temperature of, for example, 1200 to 1250°C. From this state, the upper die 2 is lowered by the driving portion 6 to start press molding of the workpiece W, and a provisional press operation Q1, a return operation Q2, and a main press operation Q3 are performed in this order (see FIG. 5). In the preparation state for press molding, no sealed space S2 is formed between the upper die 2 and the lower die 3, and a space for setting the workpiece W in the lower die 3 is formed.

[0021] In the provisional press operation Q1, the upper die 2 is lowered to a position not reaching the bottom dead center, thereby provisionally pressing the workpiece W. At the start of forming in the provisional press operation Q1 (i.e., when the pressing surface 12 of the upper die 2 starts pressing the axial end surface of the workpiece W), as shown in FIG. 6(a), the lower die holder 24 overlaps with the upper die 2, and an enclosed space S2 is formed between the lower die holder 24, the upper die 2, and the lower die 3. A suction airflow is applied within this enclosed space S2 by the operation of the air suction source 28. When the provisional press operation Q1 proceeds further from this state, the pressing surface 12 of the upper die 2 presses the axial end surface of the workpiece W, and the outer peripheral surface of the axial end of the workpiece W is restrained by the restraining surface 13 of the upper die 2.

[0022] Next, in the return operation Q2, as shown in Fig. 7, the upper die 2 is raised so as to release the temporary pressing of the workpiece W, thereby forming a gap S1 between the restraining surface 13 of the upper die 2 and the outer peripheral surface of the workpiece W. During the return operation Q2, air is supplied to the air outlet 15 by the operation of the air supply source 18, and air is injected from the air outlet 15 into the gap S1. As a result, downward spiral airflows H1 and H2 are generated in the gap S1, and the scale O on the surface of the workpiece W is scattered into the sealed space S2. The scattered scale O (specifically, the dry scale O before being mixed with the release agent) is sucked and collected by the scale collection section 27 from the sealed space S2 where the suction airflow acts, via the exhaust port 25 and the duct 26.

[0023] Next, in the main press operation Q3, as shown in Fig. 6(b), the upper die 2 is lowered to the bottom dead center to perform the main pressing of the workpiece W. As a result, the axial end surface of the workpiece W is pressed by the pressing surface 12 of the upper die 2, and the outer peripheral surface of the axial end of the workpiece W is restrained by the restraining surface 13 of the upper die 2, forming an intermediate forged product F1 (see Fig. 8(b)). After that, the upper die 2 is raised to the top dead center and returns to the ready state, completing the series of press forming operations.

[0024] Here, the intermediate forged product F1 obtained by the forging press apparatus 1A is subjected to one or more press forming operations by one or more other forging press apparatuses to produce a forged product F2 (see FIG. 8(c)). A method for producing a forged product using the forging press apparatus 1A includes a step of obtaining an intermediate forged product F1 by press forming the workpiece W while removing scale O from the surface of the workpiece W by the forging press apparatus 1A, and a step of obtaining a forged product F2 by press forming the intermediate forged product F1 once or more than once.

[0025] As described above, according to the forging press device 1A of this embodiment, the temporary press operation Q1 in which the upper die 2 is lowered to temporarily press the workpiece W, the return operation Q2 in which the upper die 2 is raised to release the temporary pressing of the workpiece W and form a gap S1 between the upper die 2 and the workpiece W, and the final press operation Q3 in which the upper die 2 is lowered to finally press the workpiece W are performed, and a sealed space S2 communicating with the gap S1 is formed between the upper die 2 and the lower die 3, and the upper die 2 is provided with an air ejection port 15 so as to open to its forming surface 11. During the return operation Q2, the scale O on the surface of the workpiece W is scattered into the sealed space S2 by air ejected from the air ejection port 15 through the gap S1, and the scattered scale O is sucked and collected from the sealed space S2 to the outside. As a result, even if there is almost no gap between the die and the workpiece as in the case of sealed forging, the scale O can be effectively collected during press forming. As a result, the scale O does not scatter on the lower die 3 or its surroundings, eliminating or reducing manual cleaning work, and preventing deterioration of the maintainability of the forging press 1A and the working environment. Moreover, since the scale O is collected in a dry state before being mixed with the release agent, a separation and collection device for separating the scale O from the release agent after the scale is collected is not required. In contrast, when pressing the workpiece W using the forging press of Patent Document 1, an air injection port is provided directly on the upper die. In this case, an appropriate gap is not formed between the upper die and the workpiece W in one press, and the state in which the scale is attached to the surface of the workpiece W is maintained, making it impossible to collect the scale.

[0026] In this embodiment, the molding surface 11 of the upper die 2 has a constraint surface 13 where the air ejection port 15 opens and which abuts against the outer peripheral surface of the workpiece W, and the constraint surface 13 has a tapered portion 13a whose diameter increases toward the lower die 3. As a result, a space S1 suitable for the flow of the spiral air currents H1 and H2 is formed between the constraint surface 13 (specifically, the tapered portion 13a) of the upper die 2 and the outer peripheral surface of the workpiece W.

[0027] In this embodiment, the restraining surface 13 of the upper die 2 has a curved end portion 13b that is continuous with the lower end portion of the tapered portion 13a. This allows the upper die 2 and the workpiece W to be smoothly separated from each other when transitioning from the preliminary pressing operation Q1 to the return operation Q2.

[0028] Moreover, in this embodiment, the upper die 2 is provided with a plurality of air jet ports 15 that open at positions shifted in the direction of the movement axis C on the molding surface 11. This makes it possible to generate stronger spiral air currents H1, H2 between the upper die 2 and the workpiece W, thereby improving the capacity to collect scale O, compared to a configuration provided with a single air jet port 15.

[0029] Furthermore, according to the manufacturing method of the forging F2 of this embodiment, an intermediate forging F1 is obtained by press-forming the workpiece W while recovering scale O on the surface of the workpiece W using the forging press device 1A, and a forging F2 is obtained by press-forming the intermediate forging F1 once or twice or more times.

[0030] <Variation 1> Next, a first modified example of the forging press device 1A will be described. In this first modified example, as shown in FIG. 9(a), the forming surface 11 of the upper die 2 has a pressing surface 12 that abuts against the axial end surface of the upper end of the workpiece W, and a restraining surface 13 in which the air ejection port 15 opens and abuts against the outer circumferential surface of the workpiece W. The restraining surface 13 has a curved portion 31a whose diameter increases toward the lower die 3. As a result, in this first modified example, a gap S1 suitable for the flow of the spiral airflows H1 and H2 is formed between the restraining surface 13 (specifically, the curved portion 31a) of the upper die 2 and the outer circumferential surface of the workpiece W. The shape, arrangement, etc. of the curved portion 31a are not particularly limited, and are determined according to the shape, etc. of the intermediate forged product F1 to be press-formed. Furthermore, the number of curved portions 31a may be one, or there may be multiple curved portions 31a having different curvatures.

[0031] <Variation 2> Next, a second modified example of the forging press apparatus 1A will be described. In this second modified example, as shown in FIG. 9(b), the forming surface 11 of the upper die 2 has a pressing surface 12 that abuts against the axial end surface of the upper end of the workpiece W, and a restraining surface 13 in which the air ejection port 15 opens and abuts against the outer circumferential surface of the workpiece W. The restraining surface 13 has a curved portion 32a and tapered portions 32b, 32c that expand in diameter toward the lower die 3. As a result, in this second modified example, a gap S1 suitable for the flow of the spiral airflows H1, H2 is formed between the restraining surface 13 of the upper die 2 (specifically, the curved portion 32a and the tapered portions 32b, 32c) and the outer circumferential surface of the workpiece W. The shapes, sizes, etc. of the curved portion 32a and the tapered portions 32b, 32c are not particularly limited and are determined according to the shape, etc. of the intermediate forged product F1 to be press-formed. Furthermore, the number of curved portions 32a may be one, or there may be multiple curved portions 32a with different curvatures. Furthermore, the tapered portions 32b and 32c may be one, or may be multiple with different taper angles.

[0032] <Embodiment 2> Next, a forging press 1B according to a second embodiment will be described. Components that are substantially the same as those in the forging press 1A of the first embodiment are given the same reference numerals and detailed description is omitted. Differences between the two will be described in detail.

[0033] As shown in Fig. 10, the forging press apparatus 1B according to this embodiment presses a workpiece (material) W between an upper die 2 and a lower die 3 which are movable toward and away from each other along a movement axis C. This forging press apparatus 1B is configured to perform a preliminary press operation Q1, a return operation Q2, and a main press operation Q3 in this order (see Fig. 5).

[0034] The upper die 2 has a convex portion 35 that protrudes downward. The molding surface 11 of the upper die 2 has a pressing surface 12 that abuts against the axial end surface of the upper end of the workpiece W, and a restraining surface (restricted outer peripheral surface) 13 where the air ejection port 15 opens and abuts against the inner peripheral surface of the workpiece W. The pressing surface 12 is formed by the lower surface of the convex portion 35. The restraining surface 13 is formed by the outer peripheral surface of the convex portion 35. The restraining surface 13 has a tapered portion 13a that decreases in diameter toward the lower die. The restraining surface 13 has a curved end portion 13b that is connected to the upper end portion of the tapered portion 13a. The curved end portion 13b decreases in diameter toward the lower die 3, and constitutes the end portion (specifically the upper end portion) of the restraining surface 13 in the direction of the moving axis C.

[0035] As described above, the forging press apparatus 1B of this embodiment achieves substantially the same effects as the forging press apparatus 1A, and the molding surface 11 of the upper die 2 has a constraint surface 13 into which the air injection port 15 opens and which abuts the inner surface of the workpiece W, and the constraint surface 13 has a tapered portion 13a whose diameter decreases as it approaches the lower die 3, so that a gap S1 suitable for the flow of a spiral air flow H is formed between the constraint surface 13 of the upper die 2 and the inner surface of the workpiece W.

[0036] <Embodiment 3> Next, a forging press 1C according to a third embodiment will be described. Components that are substantially the same as those in the forging press 1A of the first embodiment are given the same reference numerals, and detailed description is omitted. Differences between the two will be described in detail.

[0037] 11, the forging press apparatus 1C according to this embodiment presses a workpiece (material) W between an upper die 2 and a lower die 3 which are movable toward and away from each other along a movement axis C. This forging press apparatus 1C is configured to perform a preliminary press operation Q1, a return operation Q2, and a main press operation Q3 in this order (see FIG. 5).

[0038] The upper mold 2 has a cylindrical mold 2a and a central mold 2b provided at the center of the upper part of the cylindrical mold 2a. A cylindrical upper mold holder 14 that holds the cylindrical mold 2a is provided on the outer periphery of the cylindrical mold 2a. The cylindrical mold 2a is provided with a plurality of air jetting ports 15 (two in the figure) that open to the restraining surface 13. The upper mold holder 14 is also provided with an air supply path 37 that is connected to an air supply source 18 via a pipe 17. A communication path 38 that communicates the air supply path 37 and the air jetting ports 15 is provided between the inner periphery of the upper mold holder 14 and the outer periphery of the cylindrical mold 2a. The communication path 38 is formed as a cylindrical space. However, the communication path 38 may be formed as a groove-shaped space.

[0039] It should be noted that multiple types of cylindrical molds 2a having respective inner peripheral shapes corresponding to the shapes of multiple types of workpieces W may be prepared, and during a setup change, the cylindrical mold 2a may be replaced with a corresponding one, and the cylindrical mold 2a may be held by the multipurpose upper mold holder 14. Furthermore, multiple air supply paths 37 may be provided corresponding to the multiple air ejection ports 15, or one may be provided for the multiple air ejection ports 15 when the communication path 38 is a cylindrical space.

[0040] The lower die 3 has a cylindrical die 3a. The cylindrical die 3a has a holding portion 22 that holds the workpiece W. A cylindrical lower die holder 24 that holds the cylindrical die 3a is provided on the outer periphery of the cylindrical die 3a. During each of the operations Q1 to Q3, the inner periphery of the lower die holder 24 and the outer periphery of the upper die holder 14 overlap with each other, forming an enclosed space S2 between the upper die 2 and the lower die 3.

[0041] The lower die holder 24 is provided with an outlet 25 that opens into the sealed space S2 (see FIG. 12). The outlet 25 is connected to a scale collection unit 45, which will be described later, via a duct 26. Operation of the scale collection unit 45 causes a suction airflow (swirling airflow) H3 to act in the sealed space S2 through the outlet 25. In this embodiment, the operation of the scale collection unit 45 is performed at all times during press molding, including each of the operations Q1 to Q3, but may be performed during the entire period during which the sealed space S2 is formed or during a predetermined part of the period during press molding.

[0042] The discharge outlet 25 extends in a tangential direction of a circumference centered on the movement axis C. Moreover, the discharge outlet 25 extends in a direction perpendicular to the movement axis C in a side view of the lower mold 3. However, the discharge outlet 25 may extend in a direction inclined with respect to the movement axis C (for example, a downward inclination direction) in a side view of the lower mold 3. The extension direction, arrangement location, and number of the discharge outlets 25 are not particularly limited as long as the suction airflow H3 can be applied within the sealed space S2.

[0043] The lower mold holder 24 is provided with an air outlet 41 so as to open into the sealed space S2 (see FIG. 12). The air outlet 41 is connected to an air supply source 43 (e.g., an air compressor, a blower, etc.) via a pipe 42. An airflow (swirling airflow) H4 acts from the air outlet 41 into the sealed space S2 by air supply from the air supply source 43. The vertical cross-sectional area of ​​the air outlet 41 is set to a value smaller than that of the exhaust port 25 and larger than that of the air jetting port 15. In this embodiment, air is supplied from the air supply source 43 to the air outlet 41 during the entire period or a predetermined part of the period during which the sealed space S2 is formed during press molding including each of the operations Q1 to Q3, but may be supplied all the time during press molding. Furthermore, the air supply source 43 may also be used as the air supply source 18 (see FIG. 11) that supplies air to the air jetting port 15.

[0044] The air outlet 41 extends in the tangential direction of a circumference centered on the movement axis C. The air outlet 41 also extends in a direction perpendicular to the movement axis C in a side view of the lower mold 3. However, the air outlet 41 may extend in a direction inclined relative to the movement axis C (for example, a downward inclination) in a side view of the lower mold 3. The extension direction, location, and number of the air outlets 41 are not particularly limited as long as they can produce an airflow in the enclosed space.

[0045] The air outlet 41 and the exhaust port 25 are arranged so that their respective axes are substantially parallel to each other. However, the air outlet 41 and the exhaust port 25 may be arranged so that their respective axes intersect.

[0046] 13, the scale collection section 45 includes a scale separation section 46 having a backing plate 46a against which scale (specifically, air containing scale) sucked and collected through duct 26 collides, an ejector gun 47 that generates a suction airflow within the scale separation section 46, and a rotary valve 48 that controls the flow rate and discharges scale that accumulates at the bottom of the scale separation section 46. In FIG. 13, the flow of air is indicated by solid arrows, and the flow of scale is indicated by dashed arrows.

[0047] The backing plate 46a is disposed in the case 46b so as to face the end of the duct 26. The ejector gun 47 has one end 47a connected to the scale separating unit 46 and the other end 47b connected to the filter 50. The ejector gun 47 generates a suction airflow at the one end 47a and a blown airflow at the other end 47b by supplying compressed air P to an intermediate portion 47c between both ends 47a and 47b. The rotary valve 48 has a motor 48a and a rotor 48b rotated by the motor 48a. A collection box 49 for collecting scale is installed below the rotary valve 48. As the ejector gun 47, for example, a Wonder Gun (product name, manufactured by Osawa & Co.) can be used.

[0048] Next, the effects of the forging press 1C configured as above will be described. In this forging press 1C, a provisional press operation Q1, a return operation Q2, and a final press operation Q3 are performed (see FIG. 5). When an enclosed space S2 is formed between the upper die 2 and the lower die 3 during the provisional press operation Q1, a suction airflow H3 is applied to the enclosed space S2 by the scale collection section 45, and an airflow H4 is applied by air blown from the air outlet 41 (see FIG. 12). The blown airflow H4 blows off the scale that has fallen onto the lower die 3 (specifically, the cylindrical die 3a) during each operation Q1 to Q3. The blown off scale is sucked and collected by the scale collection section 45 via the duct 26 together with the scale that has been scattered in the enclosed space S2 by air jet from the air jet port 15.

[0049] In the scale collection section 45, scale collides with a contact plate 46a in the scale separation section 46, falls and accumulates at the bottom. The scale is discharged from the bottom of the scale separation section 46 while the flow rate is controlled by a rotary valve 48, and is collected in a collection box 49. Meanwhile, the air from which scale has been separated in the scale separation section 46 is released into the outside air after fine scale is removed by a filter 50.

[0050] As described above, the forging press 1C of this embodiment provides substantially the same operational effects as the forging press 1A described above, and in addition, since the lower die 3 is provided with an air outlet 41 that opens into the sealed space S2, scale that has fallen onto the lower die 3 is blown away by the airflow H4 blown out from the air outlet 41, and is sucked and collected in the scale collection section 45 via the duct 26 together with scale that has been scattered within the sealed space S2 by air jets from the air jet port 15. As a result, the scale can be collected even more effectively.

[0051] Furthermore, the scale collection section 45 of this embodiment is equipped with a scale separation section 46 having a contact plate 46a against which scale sucked and collected via the duct 26 collides, an ejector gun 47 that generates a suction airflow within the scale separation section 46, and a rotary valve 48 that controls the flow rate and discharges scale that accumulates at the bottom of the scale separation section 46. This makes it possible to collect scale even more effectively.

[0052] Specifically, with this scale collection section 45, the backing plate 46a worn due to collision with scale can be easily replaced. Furthermore, the rotary valve 48 allows the scale to be discharged while the press is in operation. In contrast, with a structure in which the scale is collided with the exterior part, it is not easy to replace the worn exterior part. Furthermore, with a structure that does not include the rotary valve 48, it is not possible to discharge the scale while the press is in operation.

[0053] The present invention is not limited to the above-mentioned embodiment, and various modifications within the scope of the present invention are possible depending on the purpose and application. In other words, the above-mentioned embodiment illustrates the vertical forging presses 1A to 1C in which the axis of movement C is vertical, but the present invention is not limited to this, and may be, for example, the horizontal forging presses 1A to 1C in which the axis of movement C is horizontal or inclined relative to the horizontal.

[0054] In addition, in the above embodiment, forging press apparatuses 1A-1C in which one die is a movable die and the other die is a fixed die (lower die 3) are exemplified, but this is not limited to this, and for example, forging press apparatuses 1A-1C in which each of a pair of dies is a movable die may be adopted.

[0055] In addition, in the above embodiment, forging press apparatuses 1A to 1C in which one die is an upper die 2 (movable die) and the other die is a lower die 3 are exemplified, but this is not limited to this, and for example, forging press apparatuses 1A to 1C in which one die is a lower die 3 (movable die) and the other die is an upper die 2 may be adopted.

[0056] In addition, in the above embodiment, forging press apparatuses 1A to 1C that perform a set of the preliminary press operation Q1 and the return operation Q2 once are exemplified, but this is not limited to this, and for example, forging press apparatuses 1A to 1C that perform a set of the preliminary press operation Q1 and the return operation Q2 multiple times may be adopted.

[0057] Furthermore, in the above embodiment, hydraulic press type forging press devices 1A-1C that perform the preliminary press operation Q1, the return operation Q2, and the main press operation Q3 are exemplified, but this is not limited to this, and for example, mechanical press type forging press devices 1A-1C that use a servo motor to perform each of the operations Q1-Q3 may be used.

[0058] Furthermore, the configurations of the forging presses 1A to 1C of the above-mentioned embodiments can be combined for use. For example, the forging presses 1A and 1B may be provided with a scale recovery section 45. Furthermore, the upper die 3 of the forging press 1C may be used as the upper die 3 of the forging presses 1A and 1B.

[0059] The present invention is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the claims of the present invention. [Industrial Applicability]

[0060] The present invention is widely used as a technique for manufacturing forged products. [Explanation of symbols]

[0061] 1A-1C; forging press apparatus, 2; upper die (one of the dies), 3; lower die (the other die), 11; forming surface of upper die, 12; pressing surface, 13; restraint surface, 13a; tapered portion, 13b; curved end, 15; air nozzle, 22; holding portion of lower die, 31a; curved portion, 32a; curved portion, 32b, 32c; tapered portion, 41; air outlet, C; axis of movement, F2; forged product, O; scale, Q1; preliminary press operation, Q2; return operation, Q3; main press operation, S1; gap, S2; enclosed space, W; workpiece.

Claims

1. A forging press device that presses a workpiece between a pair of dies that can move toward and away from each other along a moving axis, comprising: a temporary pressing operation in which the pair of dies are brought close to each other to temporarily press the workpiece; a return operation for separating the pair of dies from each other so as to release the temporary pressing of the workpiece, thereby forming a gap between one of the pair of dies and the workpiece; A final pressing operation is performed by bringing the pair of dies close to each other and final pressing the workpiece, and A sealed space communicating with the gap is formed between the pair of molds, The one of the dies is provided with an air injection port opening on its molding surface, This forging press device is characterized in that during the returning operation, air is sprayed from the air nozzle through the gap to scatter scale on the surface of the workpiece into the sealed space, and the scattered scale is sucked out of the sealed space and collected to the outside.

2. The molding surface of the one die has a restraint surface where the air ejection port opens and which abuts against an outer peripheral surface or an inner peripheral surface of the workpiece, 2. The forging press apparatus according to claim 1, wherein the restraining surface has a tapered portion and / or a curved portion that expands or contracts in diameter as it approaches the other die.

3. The forging press apparatus according to claim 2 , wherein the restraining surface has a curved end portion that is continuous with an end portion of the tapered portion or the curved portion.

4. 2. The forging press apparatus according to claim 1, wherein the one of the dies is provided with a plurality of the air injection ports so as to open at positions shifted in the direction of the movement axis on the forming surface.

5. The one die is an upper die and the other die is a lower die, The molding surface of the upper die has a pressing surface that contacts an axial end surface of the upper end of the rod-shaped workpiece, and a restraining surface where the air ejection port opens and contacts an outer peripheral surface of the upper end of the workpiece, 2. The forging press apparatus according to claim 1, wherein the lower die has a holding portion for holding a lower end portion of the workpiece.

6. 2. The forging press apparatus according to claim 1, wherein the other die is provided with an air outlet opening into the sealed space.

7. A method for manufacturing a forged product, comprising using the forging press apparatus according to any one of claims 1 to 6.

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