Forging device

Abstract

To provide a forging apparatus that can be simplified and miniaturized. [Solution] A slide member 20 is provided inside the lower mold 4 that protrudes and retracts in a direction perpendicular to the direction of vertical movement of the knockout 6 in the region in which the knockout 6 moves up and down. A cam surface 23b is provided on the outer circumferential surface of the knockout 6 that moves it between a position where the slide member 20 is in contact with the region and a position where it protrudes into the region. A connecting member 22 that operates together with the slide member 20 is provided inside the lower mold 4 together with the slide member 20. The stripper 8 is attached to the connecting member 22 and is configured to move between a position where it engages with the workpiece 2 and a retracted position where it is separated from the workpiece 2 by the connecting member 22.

Description

Technical Field

[0001] The present invention relates to an apparatus for forging a workpiece using an upper die and a lower die, and particularly to a forging apparatus provided with a stripper for separating the workpiece from the upper die.

Background Art

[0002] Forging is a process of applying a load to a workpiece to impart a predetermined shape to the workpiece. Therefore, the workpiece is in a state of being adhered to the upper die or the lower die. Thus, a forging apparatus requires a stripper or a knockout for separating the workpiece from the die. Patent Document 1 describes a forging die provided with a mechanism for such a strip and a mechanism for a knockout.

[0003] The forging die described in Patent Document 1 is an apparatus for forming a workpiece into a predetermined shape and punching a central portion by a die provided in the lower die and a punch provided in the upper die. In the upper die, a stripper for pressing a flange portion of the workpiece toward the lower die side is provided so as to be able to move up and down. Specifically, the stripper is attached to the lower end portion of a rod, the rod is held by the upper die so as to be able to move up and down, and a spring for pressing the stripper to protrude downward from the upper die is provided. On the other hand, a knockout pin that is moved up and down by a predetermined drive mechanism is disposed below the die in the lower die. In the forging die described in Patent Document 1, after the upper die descends to the bottom dead center and performs predetermined processing on the workpiece, in the process of the upper die ascending, the stripper maintains a state of pressing the workpiece toward the lower die side by the spring force. That is, the stripper relatively descends with respect to the upper die, thereby peeling the workpiece from the upper die. Thereafter, the knockout pin ascends by a predetermined drive mechanism, and the workpiece is pushed out from the lower die by the knockout pin. [[ID=十七]]

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] The apparatus described in Patent Document 1 is a forging die configured to straighten the flange of a workpiece in conjunction with forging, and for this purpose, a straightening retainer that presses the stripper toward the flange is positioned on the back side (upper side) of the stripper. Because the stripper is equipped with this straightening retainer, it firmly presses against the flange and straightens it even during the upward movement of the upper die. In the configuration described in Patent Document 1, it is essential that the stripper be installed on the upper die. In contrast, since the knockout of the workpiece is performed after the upper die has risen to its top dead center and stopped moving, the knockout pin and the mechanism that drives it must be installed separately and independently from the upper die and stripper. In other words, in conventional apparatuses such as the forging die described in Patent Document 1, the stripper and knockout, which are used to separate the workpiece from the forging die, are installed separately, including their drive mechanisms, which makes the overall configuration of the apparatus complex and potentially large, and there is still room for improvement in this respect. Furthermore, while it is possible to configure a system that links the stripper mechanism with the knockout mechanism, even with such a configuration, there is still room to develop new configurations in order to simplify or miniaturize the overall structure of the device.

[0006] This invention has been made in view of the above-mentioned technical problems, and aims to provide a forging apparatus that can be simplified and miniaturized. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides a forging apparatus comprising: an upper die and a lower die that form a predetermined shape by applying pressure to a workpiece to cause plastic deformation; a stripper that engages with the workpiece that adheres to the upper die and rises, and pulls the workpiece relatively downward to detach it from the upper die; and a knockout that pushes up the workpiece from below to detach it from the lower die, wherein a slide member that protrudes and retracts in a direction perpendicular to the direction of vertical movement of the knockout is provided inside the lower die in a region in which the knockout moves up and down; a cam surface is provided on the outer circumferential surface of the knockout that moves the slide member between a position retracted from the region and a position protruding into the region; a connecting member that operates together with the slide member is provided inside the lower die together with the slide member; and the stripper is attached to the connecting member and configured to move between a position in which it engages with the workpiece and a retracted position separated from the workpiece by the connecting member.

[0008] In the present invention, the multiple strippers may be arranged at equal intervals on the outer circumference of the workpiece, on a circle centered on the workpiece.

[0009] In the present invention, the cam surface has a lowest end, and the portion above the lowest end is an inclined surface that recedes toward the center from the outer circumferential surface of the knockout, and the lowest end may be formed on the outer circumferential surface of the knockout such that it is located higher than the slide member at the position where the workpiece, which has been pushed up by the knockout, engages with the stripper.

[0010] In the present invention, the connecting member is composed of a rotating shaft member that is held vertically inside the lower mold and rotates on a central axis along the vertical direction, the sliding member is attached to the lower end of the rotating shaft member and rotates together with the rotating shaft member so that a part of its tip protrudes into or retracts into the area, and the stripper is attached to the upper end of the rotating shaft member and rotates together with the rotating shaft member so that a part of its tip protrudes into or retracts into a position that engages with the workpiece. [Effects of the Invention]

[0011] In this invention, when the upper die descends to the bottom dead center and the forging of the workpiece is completed, the knockout also descends to the bottom dead center, and the cam surface provided on its outer circumference descends to the location of the slide member, causing the slide member to advance toward the center of the knockout. Consequently, the stripper, which is connected to the slide member by a connecting member, advances to a position where it engages with the workpiece. Therefore, when the workpiece, which is stuck to the upper die, is pulled up to the position of the stripper, the stripper engages with the workpiece and prevents it from rising further. That is, the stripper pulls the workpiece relatively down from the upper die, and the workpiece is separated from the upper die. After that, the knockout rises, retracting the slide member and the stripper to their original positions. In this way, the knockout moves up and down, causing the stripper to move back and forth relative to the workpiece, thus combining the function of knocking out the workpiece and the function of driving the stripper to separate the workpiece from the upper die. Therefore, according to this invention, the number of required components can be reduced, simplifying or miniaturizing the overall structure.

[0012] In a configuration where the strippers are arranged at equal intervals in the circumferential direction on the outer circumference of the workpiece, the pulling force can be applied evenly to the workpiece, allowing it to be smoothly pulled out of the upper die without tilting it. [Brief explanation of the drawing]

[0013] [Figure 1]This is a schematic cross-sectional view of an embodiment of the present invention. [Figure 2] This is a schematic perspective view showing a set of strippers and a sliding member. [Figure 3] This is a partial cross-sectional view showing the slide member, the cam surface, and the mechanism that presses the slide member. [Figure 4A] These are diagrams illustrating the operation of a forging apparatus, and include a plan view and a cross-sectional view showing the state during the forming process. [Figure 4B] These are diagrams illustrating the operation of a forging apparatus, showing a plan view and a cross-sectional view of the apparatus in its lowered position at the bottom dead center. [Figure 4C] These diagrams illustrate the operation of a forging apparatus, and show a plan view and a cross-sectional view illustrating the state in which a workpiece is being pulled down from the upper die by a stripper. [Figure 4D] These are diagrams illustrating the operation of a forging apparatus, showing a plan view and a cross-sectional view of a workpiece being ejected by knockout. [Modes for carrying out the invention]

[0014] Next, embodiments of the present invention will be described with reference to the attached drawings. Note that the embodiments described below are merely examples of how the present invention can be implemented and do not limit the invention.

[0015] Figure 1 shows a schematic cross-sectional view of an example of a forging apparatus 1 according to the present invention. The example shown here is an apparatus configured to form the inner and outer surfaces of a cup-shaped hollow portion 3 provided in a workpiece 2 into a predetermined shape by applying pressure and causing plastic deformation, and mainly consists of a lower die 4, an upper die 5, and a knockout die (sometimes simply referred to as a knockout) 6.

[0016] The lower die 4 has a base portion 7 that houses the knockout 6 so as to be vertically movable. The base portion 7 is provided with a through portion 8 having a circular cross-section along the vertical direction, and the knockout 6 is housed inside thereof. The inner peripheral surface on the upper end side of the through portion 8 serves as a machining surface 9 that slidably contacts the outer peripheral surface of the hollow portion 3 in the workpiece 2 and receives a load for pressing the inner peripheral surface of the hollow portion 3 outward in the radial direction.

[0017] On the upper surface of the base portion 7, a plate member 10 having a through hole that coincides with the above-mentioned through portion 8 is fixed, and a die 11 is attached thereon. The die 11 is for machining the outer peripheral surface of the hollow portion 3 in the workpiece 2 and has an inner peripheral shape corresponding to the product shape of the hollow portion 3.

[0018] The upper die 5 includes a plurality of split dies 12 that are inserted into the hollow portion 3 of the workpiece 2 and open outward in the radial direction, and a slide die 13 that is inserted inside the split die 12 and presses the split die 12 from the inside to the outside. The slide die 13 has a tapered outer peripheral surface, and the tapered portion is brought into contact with the inner peripheral surface of the split die 12. In this state, by relatively descending with respect to the split die 12, the split die 12 is configured to be expanded. Further, the lower end portion of the slide die 13 is configured to abut against the central portion of the inner peripheral surface of the hollow portion 3 in the workpiece 2 to form the inner peripheral surface of the hollow portion 3.

[0019] The knockout 6 is a cylindrical member that fits the shaft portion 14 in the workpiece 2, and is inserted into the through portion 8 provided in the base portion 7 and held so as to be vertically movable. Further, the upper end portion of the knockout 6 has a shape following the outer peripheral surface thereof so as to abut against the outer peripheral surface of the hollow portion 3 in the workpiece 2. The upper end portion of a rod 15 inserted from below abuts against the lower end surface of the knockout 6. By vertically moving this rod 15 by a driving portion not shown, the knockout 6 is configured to vertically move.

[0020] Note that in Fig. 1, the reference numeral "16" is a so-called pointed type for machining the end face of the shaft portion 14 in the workpiece 2. It has a tip portion with a triangular cross-section and is configured to form a center hole at the center of the end face of the shaft portion 14. This pointed type 16 is held by a holding plate 17 attached to the lower end portion of the base portion 7. The above rod 15 penetrates through this holding plate 17.

[0021] A mechanism for separating the workpiece 2 from the upper die 5 is provided on the above base portion 7 constituting the lower die 4. When the upper die 5 ascends, since the workpiece 2 adheres to the upper die 5 and ascends, a stripper 18 is provided which engages with the workpiece 2 to stop its ascent. The stripper 18 is a plate-like member that moves between a position protruding to the inner peripheral side of the through-hole portion 8 and a retracted position spaced apart from the workpiece 2 within the through-hole portion 8. At the upper end portion of the base portion 7 and on a circumferential portion surrounding the through-hole portion 8, a recess 19 is formed by recessing the base portion 7, and the stripper 18 is disposed inside the recess 19. Note that the recess 19 is closed by a plate member 10. Also, a plurality of strippers 18 are provided at equal intervals in the circumferential direction of the workpiece 2 or the through-hole portion 8. In the example shown in Fig. 1, the stripper 18 is substantially rectangular or fan-shaped in plan view, and rotates about one end portion thereof, and a part of the tip side (peripheral side of the fan shape) protrudes to the inner peripheral side of the through-hole portion 8 and is held so as to retract.

[0022] The mechanism for rotating the stripper 18 is configured to make the knockout 6 function as a cam. A slide member 20 is provided corresponding to each of the plurality of strippers 18. An accommodating portion 21 having the same shape as the above recess 19 is formed at an intermediate portion of the lower die 4 in the vertical direction. The accommodating portion 21 can be formed, for example, by dividing the base portion 7 vertically, partially cutting out the divided portions, and constituting it by those cutout portions. The accommodating portion 21 is disposed below each recess 19, and thus each slide member 20 is disposed at a position that coincides with the stripper 18 in the vertical direction.

[0023] The slide member 20 is, for example, a plate-shaped member with a shape almost identical to that of the stripper 18. Each stripper 18 and the slide member 20 located below it are connected to rotate together by a connecting pin (or rod) 22, which is a connecting member or rotation axis member that penetrates vertically through the inside of the lower mold 4 and rotates on its own axis. A set of strippers 18 and slide members 20 connected by the connecting pin 22 is schematically shown in Figure 2.

[0024] The slide member 20 is configured to function as a cam follower. The lower surface of the portion that protrudes to the inner circumference of the through-hole 8 is notched at an angle at the corner or machined to a curved surface, so that it is pushed up from below, generating a horizontal component force and retracting from the through-hole 8. A cam surface is provided on the outer circumferential surface of the slide member 20 that moves the slide member 20 backward in a radial direction (a direction perpendicular to the direction in which the knockout 6 moves up and down) centered on the workpiece 2. In the example shown in Figure 1, the groove 23 and the outer circumferential surface of the slide member 20 form the cam surface. That is, a groove 23 is formed along the vertical direction on the outer circumferential surface of the knockout 6 at a position corresponding to the slide member 20. This groove 23 is formed over a predetermined length from the upper end of the knockout 6, and its lowest end 23a is set at a position where the slide member 20 faces when the knockout 6 has descended to its bottom dead center, or at a position slightly lower than that. Furthermore, the depth of the groove 23 is set such that when the slide member 20 enters, the stripper 18, which is connected to it by a connecting pin 22, rotates, and a portion of its tip protrudes into the through-hole 8, and the amount of this protrusion is equal to the amount by which it engages with the workpiece 2 inside the through-hole 8. The lower end of the groove 23 is an inclined surface 23b that slopes or curves smoothly from the bottom surface of the groove 23 toward the outer circumferential surface of the slide member 20, as shown in Figure 3. This is to allow the slide member 20 to move backward smoothly.

[0025] A pressing member is provided to move the slide member 20 toward the knockout 6 side. As shown in Figures 1 to 3, the pressing member is composed of an ejection plug 24 and a spring (elastic member) 25. Specifically, a mounting hole 26 extending from the outer circumferential surface of the lower die 4 is formed at a position corresponding to the tip of the slide member 20, and the ejection plug 24 that contacts the slide member 20 and the spring 25 that presses the ejection plug 24 toward the slide member 20 are arranged inside the mounting hole 26. The slide member 20, connecting pin 22, ejection plug 24, spring 25, mounting hole 26, etc. are provided in correspondence with each stripper 18, and therefore the same number of these components are provided as the number of strippers 18.

[0026] Next, the operation of the forging apparatus 1 described above will be explained with reference to Figures 4A, 4B, 4C, and 4D. Figures 4A through 4D each show a plan view from above of the six strippers 18 arranged at equal intervals, and a cross-sectional view similar to Figure 1 showing the positions of the upper die 5, the knockout 6, and the strippers 18.

[0027] Figure 4A shows the state immediately after the start of molding, in which the knockout 6 is pushed up and the workpiece 2 is placed on top of it. The upper die 5 is inserted into the hollow portion 3 of the workpiece 2. As mentioned above, the upper die 5 is composed of a split die 12 and a slide die 13 inserted inside it, and the split die 12 is pushed open by the slide die 13, pressing the hollow portion 3 radially outward. As a result the hollow portion 3 is pressed against the die 11. In this state, the workpiece 2 is pushed down, and the hollow portion 3 is machined into a predetermined shape by the lower die 4 and the upper die 5.

[0028] In this process, the knockout 6 is pushed up by the rod 15, so the groove 23 formed on its outer circumference is higher than the slide member 20. Therefore, the outer circumference of the knockout 6, which has an outer diameter approximately equal to that of the through-hole 8, faces the slide member 20, and the slide member 20 is retracted from the through-hole 8 by the knockout 6. The stripper 18, which is connected to the slide member 20 by the connecting pin 22, is oriented in the same direction as the slide member 20. As the slide member 20 is retracted from the through-hole 8, the stripper 18 also rotates as shown by the arrow in Figure 4A, and is retracted from the through-hole 8 (i.e., the area where the workpiece 2 moves up and down). Therefore, the workpiece 2 is pushed down and machined without any problems.

[0029] Figure 4B shows the upper mold 5 and knockout 6 in their lowest position. The upper end of the workpiece 2 is lower than the position where the stripper 18 is located. The outer diameter of the split mold 12 is smaller than the inner diameter of the through-hole 8, and therefore there is space where the stripper 18 is located for the stripper 18 to protrude into the through-hole 8. On the other hand, the groove 23 formed on the outer surface of the knockout 6 has been lowered to a position facing the slide member 20. As a result, the slide member 20 is pressed by the spring 25 and rotates so that a part of it enters the inside of the through-hole 8, i.e., into the groove 23. The stripper 18, which is connected to the slide member 20 by the connecting pin 22, also rotates as shown by the arrow in Figure 4B, so that a part of the stripper 18 protrudes into the inside of the through-hole 8 above the workpiece 2. This position of the stripper 18 is the position where it engages with the workpiece 2.

[0030] When the machining of workpiece 2 is complete, the upper die 5 rises from its bottom dead center. At this time, the split die 12 and the slide die 13 rise together, so workpiece 2 is pulled up together with the upper die 5 while remaining attached to it. This process is shown in Figure 4C. When the upper die 5 begins to rise, the knockout 6 remains at its bottom dead center, and therefore the slide member 20 and the stripper 18 maintain a state in which a part of them protrudes inside the through-hole 8. As a result, the upper end of workpiece 2, which is rising attached to the upper die 5, gets caught on the stripper 18, preventing it from rising any further. Consequently, as the upper die 5 rises further, workpiece 2 is pulled away from the upper die 5 and placed on the knockout 6. At this time, since multiple strippers 18 are arranged at equal intervals in the circumferential direction of workpiece 2, workpiece 2 is pulled down relative to the upper die 5 at multiple points on its upper end. Therefore, workpiece 2 does not tilt and can be smoothly removed from the upper die 5.

[0031] As soon as the workpiece 2 is pulled away from the upper die 5, or immediately thereafter, the knockout 6 is pushed up by the rod 15 and begins to rise. This state is shown in Figure 4D. As the knockout 6 rises from its bottom dead center, the lowest end 23a of the groove 23 moves above the position where the slide member 20 is located. As a result, the slide member 20 is gradually retracted by the inclined surface 23b formed at the lower end of the groove 23, and is finally held in its most retracted position by the outer circumferential surface of the knockout 6. The stripper 18 rotates in the same way as the slide member 20, as shown by the arrow in Figure 4D, and operates in a position that is radially retracted outward from the through-hole 8, that is, in a position that is retracted from the region in which the workpiece 2 moves up and down. In this state, the knockout 6 rises further, so the workpiece 2 is ejected from the through-hole 8 (lower die 4) without interfering with the stripper 18 and detaches from the lower die 4, completing the machining process.

[0032] In the forging apparatus 1 according to the present invention, as described above, the knockout 6 not only ejects the completed workpiece 2 from the lower die 4, but also moves up and down to move the stripper 18 between a position that engages with the workpiece 2 and a position that does not interfere with the workpiece 2. In other words, the knockout 6 also has the function of driving the stripper 18, so there is no need to newly provide a dedicated driving means for the stripper 18, and as a result the overall configuration of the apparatus can be simplified or miniaturized.

[0033] It should be noted that the present invention is not limited to the embodiments described above. The stripper and slide member may be configured to move linearly back and forth in the radial direction of the workpiece or through-hole, instead of rotating around a predetermined axis along the vertical direction of the lower die and moving back and forth toward the workpiece or through-hole. Therefore, the shape of the stripper and slide member may be any shape other than rectangular or fan-shaped. Furthermore, the cam groove in the so-called cam mechanism for moving the stripper back and forth by the knockout does not need to be a groove that is long in the axial direction of the knockout, but may be a groove formed along the circumferential direction on the outer surface of the knockout. [Explanation of Symbols]

[0034] 1 Forging equipment 2 Work 3 Hollow part 4 Lower mold 5 Upper mold 6 Knockouts 7 Base section 8 Penetration 9 Machining surface 10 Plate members 11 dice 12 split type 13 Slide type 14. Shaft section 15 rods 16 Pointed type 17 Retaining plate 18 Strippers 19 Recess 20 Sliding member 21 Storage Unit 22 connecting pins 23 Groove 23a Bottom end 23b Slope 24 plugs 25 Springs 26 mounting holes

Claims

1. A forging apparatus comprising an upper die and a lower die that form a predetermined shape by applying pressure to a workpiece to cause plastic deformation, a stripper that engages with the workpiece which is attached to the upper die and rising, and pulls the workpiece relatively downward to detach it from the upper die, and a knockout that pushes the workpiece up from below to detach it from the lower die, A sliding member is provided inside the lower mold that protrudes and retracts in a direction perpendicular to the direction of vertical movement of the knockout in the region in which the knockout moves up and down, The outer circumferential surface of the knockout is provided with a cam surface that moves the slide member between a position where it is retracted from the region and a position where it protrudes into the region. A connecting member that operates together with the slide member is provided inside the lower mold together with the slide member. The stripper is attached to the connecting member and is configured to move by the connecting member between a position in which it engages with the workpiece and a retracted position in which it moves away from the workpiece. A forging apparatus characterized by the following features.

2. A forging apparatus according to claim 1, Multiple strippers are arranged at equal intervals on the outer circumference of the workpiece, centered on the workpiece. A forging apparatus characterized by the following features.

3. A forging apparatus according to claim 1 or 2, The cam surface has a lowest end, and the portion above the lowest end is an inclined surface that recedes toward the center from the outer circumferential surface of the knockout. The lowermost end is formed on the outer circumferential surface of the knockout such that it is positioned higher than the sliding member at the point where the workpiece, which has been pushed up by the knockout, engages with the stripper. A forging apparatus characterized by the following features.

4. A forging apparatus according to claim 1 or 2, The connecting member is held vertically inside the lower mold and is composed of a rotating shaft member that rotates about a central axis along the vertical direction. The slide member is attached to the lower end of the rotating shaft member and rotates together with the rotating shaft member, so that a part of its tip protrudes into and retracts into the region. The stripper is attached to the upper end of the rotating shaft member and is configured to rotate together with the rotating shaft member so that a portion of its tip protrudes and retracts to a position where it engages with the workpiece. A forging apparatus characterized by the following features.

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