Forging device

Abstract

To provide a forging device configured so that an upper die can be suppressed from deviating during forging and a mechanism for the suppressing can be easily prepared.SOLUTION: A forging device comprises a fixed lower die and an upper die facing the lower die, and forges a material placed on the lower die using the upper die to make the forged material. The forging device further comprises a cylindrical body installed on the lower die to cover a side surface of the upper die over a range in height extending from a position where the lower die is fixed to a position the upper die can move vertically. The cylindrical body has an upper die guide structure in which the side surface of the upper die slides vertically on an inner surface thereof. Surfaces on which the cylindrical body and the lower die are installed have spigot structures. The side surface of the upper die has a protrusion part. A notched groove opened to an upper end of the cylindrical body, which has a depth more than a depth of the protrusion part positioned at a lowest position during forging, is formed at a position of the cylindrical body with which the protrusion part contacts when the upper die forging moves vertically.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a forging device for obtaining a forged material by forging a material placed on a lower die with an upper die. [Background technology]

[0002] Forging is classified into types such as cold forging, warm forging, hot forging, etc. according to the forging temperature at that time, and also into types such as die forging, free forging, upset forging, etc. according to the shape of the forged material at that time. Forging devices used for such forging are generally structured to have a fixed lower die and an upper die facing the lower die, and to obtain a forged material by forging a material placed on the lower die with the upper die (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-021213 A [Patent Document 2] JP 2016-052673 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when forging is performed with the forging device, a guide has been used to guide the upper die so that the upper die does not shift while descending toward the material placed on the lower die. For example, the above Patent Documents 1 and 2 propose a "punch guide having a guide hole through which the punch can slide up and down." And, Patent Document 2 proposes a "forging die device having a positioning convex portion on the upper surface of the lower die and a positioning concave portion on the lower surface of the punch guide with which the positioning convex portion engages" so that the punch guide itself does not shift. However, for example, if the material is a high-strength material such as a nickel alloy or titanium alloy, or if these materials are large and the deformation load during forging is large, the forging device and die are also large. And, as such forging, for example, a case where a high-strength large material such as a steel ingot is hot forged is considered, but if the preparation process before starting this forging takes time, there is a concern that the temperature of the heated material will drop, etc., causing problems in forging. An object of the present invention is to propose a mechanism for suppressing misalignment of the upper die during forging, and to provide a forging device that can easily prepare the mechanism. [Means for solving the problem]

[0005] The present invention relates to a forging device having a fixed lower die and an upper die facing the lower die, and forging a material placed on the lower die by the upper die, The forging device further includes a cylindrical body that is installed in the lower die and covers a side surface of the upper die over a height range from a fixed position of the lower die to a position where the upper die can be moved up and down, The cylindrical body has an upper mold guide structure in which the side surface of the upper mold slides up and down along the inner surface of the cylindrical body, and the installation surface between the cylindrical body and the lower mold has a spigot structure, This is a forging device in which the side surface of the upper die has a protrusion, and at the position of the cylindrical body where the protrusion hits when the upper die moves up and down during forging, a notched groove is formed that is open to the upper end of the cylindrical body and is deeper than when the protrusion is in its lowest position during forging.

[0006] Preferably, the forging device has the protrusions located at opposing positions on the side surface of the upper die, and the notch groove of the cylindrical body is formed at a position corresponding to the position of the protrusions. Effect of the Invention

[0007] According to the present invention, the upper die can be accurately guided to the appropriate position of the lower die during forging, and the number of preparatory steps before forging can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an example of a cross section of a conventional forging device. [Diagram 2] 1 is a schematic diagram showing an example of a cross section of a forging device according to the present invention. FIG. [Diagram 3] FIG. 4 is a schematic diagram showing an example of a cross section of another forging device of the present invention. [Figure 4] 2 is a schematic diagram showing an example of details of an upper die and a cylindrical body of the forging device of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (1) The forging device of the present invention is a forging device having a fixed lower die and an upper die facing the lower die, and forging a material placed on the lower die with the upper die to obtain a forged material. First, this configuration will be described with reference to Fig. 1. Fig. 1 shows a cross section of a forging device 0 having a fixed lower die 1 and an upper die 2 that faces the lower die 1 and is movable up and down. That is, a material 3 placed on the lower die 1 is forged by the upper die 2 to obtain a forged material 4. More specifically, the heated cylindrical material 3 is compression molded from its upper surface, and is hot upset forged into a forged material 4 having a roughly barrel shape.

[0010] In Fig. 1, before forging starts, the upper die 2 waits in a position (called the uppermost position) where it contacts the top surface of the material 3. Alternatively, before forging starts, the upper die 2 may wait in a position above and away from the top surface of the material 3. Next, when forging starts, the upper die 2 descends toward the lower die 1 to compress the top surface of the material 3, and forging continues until the material 3 is compression-molded into a forging material 4 of a predetermined height. Then, when this compression molding is completed, the descent of the upper die 2 stops, and forging ends at a position (called the lowermost position) where the upper die 2 contacts the top surface of the forging material 4.

[0011] (2) The forging device of the present invention further "has a cylindrical body that is installed on the lower die and covers the side surface of the upper die over a height range from a fixed position of the lower die to a position at which the upper die can move up and down." In the case of the forging device of FIG. 1, if the deformation load during forging is large, there is a concern that the upper die 2 may shift left and right from the initially adjusted (centered) position due to a large reaction force on the upper die 2 during forging. If this happens, the forged material 4 of the desired shape may not be obtained. Therefore, the forging device of the present invention further has a cylindrical body 5 covering the side surface of the upper die 2 as shown in FIG. 2, in addition to the configuration of the forging device of FIG. 1. The cylindrical body 5 is installed on the lower die 1, and the height of the cylindrical body 5 ranges from the position of the lower die 1 to a position where the upper die 2 can move up and down (i.e., a position between the uppermost position and the lowermost position of the upper die 2), so that the cylindrical body 5 functions to suppress the shifting of the upper die 2 during forging, as described below.

[0012] (3) The forging device of the present invention has an "upper die guide structure in which the side surface of the upper die slides up and down along the inner surface of the cylindrical body" and "the mounting surfaces of the cylindrical body and the lower die have a spigot structure."

[0013] <Upper die guide structure> First, the cylindrical body 5 covers the side surface of the upper die 2 over a range between the uppermost and lowermost positions of the upper die 2 (FIG. 2), and during forging, the side surface of the upper die 2 slides against the inner surface of the cylindrical body 5 and moves up and down while being constrained, so that the cylindrical body 5 functions as a "guide" that guides the upper die 2 to an appropriate position in the lower die 1 during forging. Note that although it is written as "sliding" here, strictly speaking, there may be "play (clearance)" between the inner surface of the cylindrical body 5 and the side surface of the upper die 2 within an allowable range.

[0014] In addition, the cylindrical body 5 does not need to cover the "entire area" of the side of the upper die 2 in the height direction of the side of the upper die 2 "over a range between the uppermost position and the lowermost position of the upper die 2." In other words, if "at least one area (i.e., only the lower area)" in the height direction of the side of the upper die 2 is covered by the cylindrical body 5 when the upper die 2 is at the uppermost position (waiting position before forging) (FIG. 3), the upper die 2 during forging will be lowered from this uppermost position and will be inevitably guided by the inner surface of the cylindrical body 5, so that it functions as a guide. And, since the cylindrical body 5 is installed on the lower die 1 as described later, it is realistic that the cylindrical body 5 covers "the entire area" or "almost the entire area" of the side of the upper die 2 in the height direction when the upper die 2 is at the lowermost position (end position of forging) (FIGS. 2 and 3).

[0015] <Inlay structure> In the present invention, it is important that the cylindrical body 5 is placed on the lower die 1, and that the mounting surfaces of the cylindrical body 5 and the lower die 1 at this time have a "spigot structure". The spigot structure is a structure in which one mounting surface of the parts to be combined is machined into a concave shape and the other mounting surface is machined into a convex shape, making it difficult for the parts to shift from each other. This structure makes it difficult for the cylindrical body 5 to shift from the lower die 1 during forging, so that the upper die 2 can be guided to the appropriate position of the lower die 1 during forging. In this respect, the spigot structure according to the present invention can also be called an "upper die centering mechanism".

[0016] As a specific spigot structure, even if the cylindrical body 5 is simply shaped like a "simple cylinder" that covers the side surface of the lower die 1, the inner surface of this cylindrical body 5 (specifically, the lower part or lower end of the inner surface) becomes the concave side (lid side) of the spigot structure, and the side surface of the lower die 1 becomes the convex side (box side) of the spigot structure, and they fit together, so that a spigot structure can be imparted (for example, as shown in Figures 2 and 3). Alternatively, without being limited to this form, various spigot structures can be imparted between the installation surfaces of the cylindrical body 5 and the lower die 1.

[0017] (4) In the forging device of the present invention, "the side surface of the upper die has a protrusion." And, when the upper die moves up and down during forging, "at the position of the cylindrical body where the protrusion comes into contact, a notch groove is formed that is open to the upper end of the cylindrical body and is deeper than when the protrusion is at its lowest position during forging." The forging device of the present invention satisfies the above requirements (1) to (3), and thus can suppress the upper die from shifting to the left or right during forging. However, in order to achieve this effect, the forging device of the present invention requires a cylindrical body that serves as a guide for the upper die during forging, in addition to the conventional lower die and upper die. Since this cylindrical body covers "almost the entire" upper and lower dies from their sides, if the upper and lower dies are large, the diameter of the cylindrical body may become larger than the forging surfaces of the upper and lower dies. In particular, if the height of the material is large, such as in the upset forging of a steel ingot, the height of the cylindrical body may also become large.

[0018] In the present invention, if the forging of a large material using such upper and lower dies is to be handled, even if the lower die is attached to the forging device before the heated material is carried into the forging device in the preparation process before the start of forging, it is not realistic to also attach the upper die and the cylindrical body. In this case, a realistic preparation process is to first place the material on the lower die that is attached and fixed to the forging device in advance. Next, before or after the process of placing the upper die on the upper surface of the material, the cylindrical body that covers and guides the side of the upper die is also placed on the lower die together with the material, and joined to the lower die in a spigot structure. Then, forging is performed by pressing down the upper surface of the upper die prepared in such a process with the ram of the forging device. Then, when forging is performed with a forging device having the above requirements (1) to (3), a "special process" of placing the above cylindrical body on the lower die from above the material is added before or after the process of placing the upper die on the upper surface of the material. In other words, compared to the conventional method, it takes more man-hours just to place the cylindrical body. Furthermore, since it is difficult to place the material on the lower die after the cylindrical body has been placed, if this is hot forging, there is a concern that the temperature of the material previously placed on the lower die will drop.

[0019] Therefore, in the forging device of the above requirements (1) to (3), if the cylindrical body before being placed in the lower die and the upper die are placed "at the same time", the man-hours for placing the cylindrical body according to the present invention can be merged with the process of placing the upper die in the forging device (placing it on the material), and the preparation man-hours before forging can be reduced. In other words, the upper die is "preliminarily" placed inside the cylindrical body that is still outside the forging device, and then this cylindrical body is transported "together with the upper die" into the forging device and placed on the lower die so as to cover the material already placed on the lower die. Then, by pressing down the upper die with the ram installed in the forging device, forging can be started immediately. And when forging is completed, if the cylindrical body is removed "together with the upper die" from the forging material, the clean-up man-hours can also be reduced.

[0020] Therefore, in the present invention, in order to achieve a structure that allows the above-mentioned cylindrical body to be transported "together with the upper die", first, the side surface of the upper die 2 has a protrusion 6 in Figures 2 and 3. Then, a notch groove 7 into which the protrusion 6 fits is formed at a position on the cylindrical body 5 that the protrusion 6 will come into contact with when the upper die 2 moves up and down during forging. Then, as shown in detail in Figure 4, this notch groove 7 is a notch groove that opens to the upper end of the cylindrical body 5, and is a notch groove that is deeper than when the protrusion 6 that descends during forging is at its lowest position.

[0021] By doing this, first, in the preparation stage for forging, the protrusion 6 on the side of the upper die 2 is aligned with the notch groove 7 in the cylindrical body 5, and then the upper die 2 is dropped into the notch groove 7 opened at the top end of the cylindrical body 5, and then, when the side of the cylindrical body 5 is grasped and lifted, the protrusion 6 on the side of the upper die 2 that tries to slip out from inside the cylinder gets caught on the bottom of the notch groove 7 in the cylindrical body 5, and the upper die 2 does not fall out from the bottom end of the cylindrical body 5. Furthermore, during forging, as the upper die 2 descends, the protrusion 6 also descends, and by making the depth of the notch groove 7 of the cylindrical body 5 into which it is fitted deeper than when the protrusion 6 is at its lowest position during forging (when it is at the position of the upper die 2 at the end of forging), the achievement of the planned reduction amount is not impeded. Furthermore, by making the depth of the notch groove 7 roughly coincident with the lowest position of the above-mentioned protrusion 6 during forging, the protrusion 6 during forging will not descend below the bottom of the notch groove 7, which also prevents excessive reduction.

[0022] The protrusion 6 can be, for example, a rod-shaped pin. By forming the tip of this pin into a flattened shape, for example, it is possible to suppress lateral displacement of the upper die 2. There is no restriction on the width of the notch groove 7. However, by making the groove width close to the size of the protrusion 6, it is possible to suppress the upper die 2 from rotating in the horizontal direction during forging.

[0023] (5) The forging device of the present invention is preferably one in which "the protrusions are located at opposing positions on the side of the upper die, and the notch groove of the cylindrical body is formed at a position corresponding to the position of the protrusions." 2 and 3, "one combination" of the protrusion 6 and the notched groove 7 is provided at "two positions (both sides)" that face each other on the left and right sides of the paper. By doing this, even if there is a clearance between the inner surface of the cylindrical body 5 and the side of the upper die 2, the horizontality of the upper die 2 is maintained during transportation, and the posture when it is placed on the lower die 1 or when it is separated from the lower die 1 becomes more stable. Furthermore, the horizontality of the upper die 2 during forging is maintained, allowing for more stable forging. More preferably, by providing one combination of the above-mentioned projection 6 and notch groove 7 at other opposing positions, the posture of the upper die 2 during transportation or forging can be further stabilized. For example, Fig. 4 shows an example in which one combination of the projection 6 and notch groove 7 is provided at four opposing positions (cross positions). EXAMPLES

[0024] A forging apparatus 0 having a combination of a lower die 1, an upper die 2, and a cylindrical body 5 for hot upset forging a material, as shown in Figures 3 and 4, was prepared. At this time, the side shapes of the lower die 1 and the upper die 2 are approximately circular, and when the cylindrical body 5 is fitted thereto, the clearance between the above-mentioned side and the inner surface of the cylindrical body is approximately 1.5 mm on one side. The material 3 is a cylindrical shape made of a nickel-based superalloy, with a diameter of approximately 560 mm and a height of approximately 1225 mm.

[0025] First, as a preparation stage for forging, outside the forging device, the protrusion 6 on the side of the upper die 2 was dropped into the notch groove 7 opened at the upper end of the cylindrical body 5 until the protrusion 6 abutted against the bottom of the notch groove 7, and the upper die 2 was placed inside the cylindrical body 5. Then, the material 3 removed from the heating furnace was placed on the lower die 1 previously attached and fixed to the forging device, and the outer surface of the cylindrical body 5 was immediately grasped, and the upper die 2 with the cylindrical body 5 placed inside the cylinder was transported into the forging device, and joined to the lower die 1 in a spigot structure so as to cover the material 3. At this time, the lower surface (forging surface) of the upper die 2 was placed in contact with the upper surface of the material 3, so that it rose relatively from the cylindrical body 5 (pushed up by the upper surface of the material 3) and waited at the highest position.

[0026] By the above preparation process, the upper surface of the part of the upper die 2 that is placed in contact with the upper surface of the blank 3 and that protrudes from the upper end of the cylindrical body 5 is pressed down by the ram of the forging device, and upset forging is immediately started. Then, the upper die 2 descends while being guided by the inner surface of the cylindrical body 5, and just before the protrusion 6 of the upper die 2 abuts on the bottom of the notched groove 7 of the cylindrical body 5, the upper die 2 reaches its lowest position (the position of the upper die 2 at the end of forging), and the forging is completed. Then, after this, the outer surface of the cylindrical body 5 can be similarly grasped and removed together with the upper die 2 from the forging material 4, and the barrel-shaped forging material 4 as designed can be obtained. [Explanation of symbols]

[0027] 0 Forging equipment 1 Lower mold 2 Upper mold 3. Materials 4 Forging material 5. Cylindrical body 6 Protrusion 7 Notch groove

Claims

1. A forging device having a fixed lower die and an upper die facing the lower die, forging a material placed on the lower die by the upper die, The forging device further includes a cylindrical body that is installed on the lower die and covers a side surface of the upper die over a height range from a fixed position of the lower die to a position where the upper die can move up and down, The cylindrical body has an upper mold guide structure in which the side surface of the upper mold slides up and down along the inner surface of the cylindrical body, and the installation surfaces of the cylindrical body and the lower mold have a spigot structure, A forging device characterized in that the side surface of the upper die has a protrusion, and a notched groove that is open to the upper end of the cylindrical body is formed at the position of the cylindrical body where the protrusion hits when the upper die moves up and down during forging, and the notched groove is deeper than when the protrusion is in its lowest position during forging.

2. 2. The forging device according to claim 1, wherein the protrusions are located at opposing positions on a side surface of the upper die, and the notched groove of the cylindrical body is formed at a position corresponding to the position of the protrusions.

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