Forging molding device and forging molding method

Abstract

To provide a forging molding device capable of improving production efficiency.SOLUTION: A forging molding device 10 comprises a molding die 20 that performs forging molding on a material M and a punch 11 that pushes the material M toward the molding die 20 disposed on the front side in a molding direction. The punch 11 has, at an end portion on a contact side that comes into contact with the material M, an accommodating part 112 that accommodates a surplus portion M6 generated in the material M by a branch flow directed rearward in the molding direction among material flows generated in the material M during forging molding. In this case, the punch 11 pushes a plurality of materials MA, MB toward the molding die 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a forging apparatus and a forging method. [Background technology]

[0002] Conventionally, for example, a forging method and a forging device (hereinafter referred to as "forging method, etc.") disclosed in Patent Document 1 have been known. In conventional forging methods, in one forging step, the outer diameter of a material before it is forced into a forming space of a die is constrained, and the material is forced into the forming space to complete the forging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-38032 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional forging methods, when a punch P forges a plurality of blanks Ma and Mb into a forming space of a die S in one forging process as shown in FIG. 11 , a surplus portion Mw may be generated in the blank Mb located at the rear in the forging direction due to material flow. In this case, the surplus portion Mw generated at the mating portion between the punch P and the die S may be cut off. For this reason, for example, when forging products continuously, it is necessary to provide a removal process in the forging process to remove the cut-off surplus portion Mw remaining inside the die S. Increasing the number of removal processes in this way may affect production efficiency, and therefore there is room for improvement.

[0005] An object of the present invention is to provide a forging apparatus and a forging method that can improve production efficiency. [Means for solving the problem]

[0006] The forging device of the present invention comprises a forming die that performs forging on a material, and a punch that pushes the material toward the forming die that is positioned forward in the forming direction, and the punch has a storage portion at the end on the contact side that contacts the material that stores excess material that is generated in the material due to the material flow that occurs in the material during forging being diverted toward the rear in the forming direction.

[0007] In addition, the forging method of the present invention includes a first forging process in which an intermediate product is formed from the raw material by forging the raw material using the forging device described above, and a second forging process in which a final product is formed from the intermediate product by forging the intermediate product. [Effects of the Invention]

[0008] According to the present invention, the receiving portion provided in the punch can receive the excess portion generated during forging. This prevents the excess portion from being cut off during forging, and as a result, the excess portion is ejected outside the forming die together with the raw material after forging. This prevents the excess portion from remaining inside the forming die during the forging process, even when products are continuously forged, eliminating the need for a removal process. Therefore, when a forging device is used, in other words, in a forging method using a forging device, the production efficiency of forging can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 3 is a diagram illustrating a forging device that performs a first forging step and a second forging step. FIG. [Figure 2] FIG. 1 is a diagram for explaining a material. [Figure 3] FIG. 10 is a diagram illustrating a housing portion for a punch. [Figure 4] FIG. 3 is a cross-sectional view illustrating a first forming die. [Figure 5] FIG. 4 is a cross-sectional view illustrating a second forming die. [Figure 6] FIG. 10 is a diagram illustrating an intermediate molded product. [Figure 7] FIG. 2 is a diagram for explaining the final molded product. [Figure 8] 10A and 10B are diagrams for explaining a state in which the storage section stores the surplus section. [Figure 9] FIG. 10 is a diagram illustrating the excess portion after being discharged from the forming die. [Figure 10] FIG. 10 is a diagram illustrating the excess portion after being discharged from the forming die. [Figure 11] 10A and 10B are diagrams for explaining a state in which an excess portion is cut off in a conventional forging method or the like. DETAILED DESCRIPTION OF THE INVENTION

[0010] The configuration of a forging apparatus 10 will be described with reference to Fig. 1. The forging apparatus 10 includes a punch 11, a mandrel 12, a drive unit 13, a table 14, a pressure plate 15, and a forming die 20, and performs forging, more specifically, cold forging, on an object to be formed. In this embodiment, the object to be formed is an annular blank M having a through hole M1 as shown in Fig. 2, and a pinion gear W is formed as a product by cold forging the outer peripheral surface of a side portion M2 of the blank M.

[0011] Here, the outer dimension Dm of the material M (in this embodiment, the material M is annular, so the outer diameter dimension Dm) is set to be smaller than the outer diameter dimension Df of the pinion gear W formed by cold forging. In this embodiment, the material M is formed in advance with chamfered portions M3 of a predetermined size at both ends in the axial direction.

[0012] In this embodiment, the forging apparatus 10 cold forges a pinion gear W as a product from a raw material M. However, the product forged by the forging apparatus 10 may be any product formed by utilizing the outward material flow (divergence) of the axial and outward material flow of the raw material due to cold forging. Therefore, the forging apparatus 10 can cold forge a spline on a shaft-shaped raw material, or cold forge a keyway or key on a shaft-shaped or annular raw material, for example.

[0013] The punch 11 is a member that is driven in the axial direction by a drive device 13 to push the material M toward the forming die 20 without restricting its outer shape. As shown in FIG. 3 , the punch 11 has a plurality of small diameter portions 111 that are provided at equal intervals along the circumferential direction to match the shape of the pinion gear W, more specifically, to match the shapes of the forming spaces 212 and 222 of the first forming die 21 and the second forming die 22 that constitute the forming die 20, which will be described later. The small diameter portions 111 extend along the axial direction of the punch 11. This allows the portions of the punch 11 that form the small diameter portions 111 to pass through the first forming die 21 and the second forming die 22 together with the material M (the intermediate formed product Fi, which will be described later).

[0014] Furthermore, the punch 11 has a recessed accommodating portion 112 extending along the axial direction at the end of the contact side that contacts the material M in the axial direction during cold forging, i.e., the end on the side to which the mandrel 12 is connected. As will be described later, the accommodating portion 112 accommodates, without cutting, excess portions M6 (see FIG. 8 ) such as burrs that are generated on the material M and the intermediate formed product Fi due to a rearward diversion in the forming direction of the material flow that occurs in the material M and the intermediate formed product Fi during cold forging. Here, in this embodiment, the accommodating portion 112 is provided in the small diameter portion 111 as shown in FIG. 3 . However, the accommodating portion 112 may also be provided in a portion of the punch 11 other than the small diameter portion 111 (a general portion with a diameter larger than the small diameter portion 111) depending on, for example, the product to be cold forged.

[0015] In the following description, the direction in which the punch 11 pushes the material M toward the forming die 20 is referred to as the "forming direction." In this embodiment, as shown in FIG. 1, a case in which the punch 11 pushes the material M into the forming die 20 in a forming direction along the vertical direction is exemplified. However, the forming direction is not limited to a direction along the vertical direction, and may be, for example, a direction along the horizontal direction.

[0016] 1, for ease of understanding, the punch 11 is shown as being virtually divided into two halves along the axis. In this case, the left side of the drawing shows the punch 11 in an elevated state, and the right side of the drawing shows the punch 11 in a lowered state. It goes without saying that the actual punch 11 is not divided into left and right halves, and is raised and lowered as a unit by the drive unit 13.

[0017] The mandrel 12 is provided on the tip side of the punch 11, and is inserted into the through hole M1 of the material M during cold forging. Here, the mandrel 12 may be attached to the punch 11 when the material M is hollow, for example, annular, or may be provided integrally with the punch 11 exclusively for cold forging of the annular material M. When versatility is taken into consideration, it is preferable to adopt a system in which a separate mandrel 12 is attached to the punch 11.

[0018] The drive unit 13 drives the punch 11 in the axial direction, i.e., the forming direction. The drive unit 13 includes, as its main elements, for example, a hydraulic mechanism, an electric mechanism, or a mechanism combining a hydraulic mechanism and an electric mechanism (not shown), and transmits the driving force generated by these mechanisms to the punch 11. In this embodiment, the drive unit 13 transmits the driving force to the punch 11 so as to raise or lower the punch 11 in the vertical direction, which is the forming direction.

[0019] The table 14 is a plate-like member that is disposed in front of the punch 11 in the forming direction, i.e., in this embodiment, downward in the vertical direction, and supports the drive unit 13. The table 14 also has a through-hole in the center, and supports the annular (cylindrical) forming die 20, pressure plate 15, and holding plate 16 coaxially with the through-hole. Furthermore, the table 14 also supports the forming load that occurs during cold forging, which will be described later.

[0020] The pressure plate 15 is an annular member having a through hole on the inside. The pressure plate 15 supports a forming die 20 disposed behind it in the forming direction. As will be described later, the pressure plate 15 ejects the pinion gear W that has been cold forged by the forming die 20 through a through hole disposed coaxially with the through hole of the table 14 while being supported by the table 14.

[0021] Next, the configuration of the forming die 20 will be described. The forming die 20 performs cold forging on the material M and the intermediate formed product Fi (see FIG. 6) so that the area reduction rate, which represents the ratio of the cross-sectional area after forming to the cross-sectional area before forming, is, for example, 10% to 40%, as shown in the following formula. Here, the area reduction rate indicates the difficulty of deformation when performing cold forging involving drawing (the larger the area reduction rate, the more difficult the deformation). Cross-sectional area reduction rate = {1 - (cross-sectional area after molding / cross-sectional area before molding)} x 100 [%]

[0022] If the area reduction rate is less than 10%, for example, the material flow when forming the intermediate product Fi from the raw material M is small, resulting in a small forming load. However, the material flow when forming the final product Ff, i.e., the pinion gear W, from the intermediate product Fi is large, resulting in a large forming load. As a result, the intermediate product Fi before being pressed into the forming die 20 is upset and expands (thickens) outward, making cold forging impossible. Furthermore, if the area reduction rate is set to less than 10%, there is insufficient material to flow outward from the raw material M and the intermediate product Fi. As a result, the spur tooth M5 (see FIG. 7), which is the final shape of the final product Ff, i.e., the pinion gear W, cannot be sufficiently thickened.

[0023] On the other hand, if the area reduction rate is set to be greater than 40%, for example, the material flow increases when forming the intermediate formed product Fi from the raw material M, resulting in a larger forming load. As a result, the raw material M before being pressed into the forming die 20 is upset and spreads outward, making forging impossible. Also, if the area reduction rate is set to be greater than 40%, the intermediate formed product Fi before being pressed into the forming die 20 is upset and spreads outward, making it impossible to forge the final formed product Ff, i.e., the pinion gear W.

[0024] As described above, the reduction in area is preferably set to 10% to 40% from the viewpoint of forging formability, but is more preferably set to 10% to 30% from the viewpoint of reducing the forming load and increasing thickness, and is even more preferably set to 10% to 20%.

[0025] 1, the forming die 20 includes a first forming die 21 and a second forming die 22. The forming die 20 also includes a spacer 23 that is arranged so that the first forming die 21 and the second forming die 22 are appropriately spaced apart when they are arranged in series.

[0026] The first forming die 21 forms an intermediate shape (see FIG. 6) in the material M so that a first cross-sectional reduction rate, which represents the ratio of the cross-sectional area of ​​the intermediate formed product Fi to the cross-sectional area of ​​the material M along a direction perpendicular to the forming direction, is 10% to 40% in a forming target portion where the intermediate shape is to be formed in the material M. To this end, the first forming die 21 has a guide portion 211 arranged rearward in the forming direction (upward in the vertical direction in this embodiment), and a forming space 212 arranged forward in the forming direction relative to the guide portion 211 (downward in the vertical direction in this embodiment), as shown in FIG.

[0027] The guide portion 211 has a holding portion 211A on its inner peripheral surface along the axial direction so as to stably insert and guide the material M advancing forward in the molding direction (downward in the vertical direction) into the molding space 212. The molding space 212 has a molding portion 212A on its inner peripheral surface along the axial direction so as to mold temporary external teeth M4 (see FIG. 6) parallel to the rotation axis on the side portion M2 of the material M.

[0028] 4, the inner diameter dimension D0 of the holding portion 211A of the guide portion 211 is set to be approximately equal to the outer diameter dimension Dm (see FIG. 2) of the raw material M. Also, as shown in FIG. 4, the inner diameter dimension D0 of the holding portion 211A of the guide portion 211 is set to be larger than the inner diameter dimension D1 of the molding space 212. The inner diameter dimension D1 of the molding space 212 is set so that the first cross-sectional area reduction rate of the side portion M2 of the raw material M falls within the above-mentioned range of 10% to 40%.

[0029] As a result, when the material M is forced into the first forming die 21, the holding portion 211A of the guide portion 211 first holds the material M without any rattle. Then, the forming portion 212A of the forming space 212 forms an intermediate formed product Fi having temporary external teeth M4 parallel to the rotation axis from the material M held by the holding portion 211A and entering the forming space 212. Note that if the inner diameter dimension D0 of the holding portion 211A is set smaller than the outer diameter dimension Dm of the material M, the holding portion 211A can also form a guide groove in the side portion M2 of the material M.

[0030] The second forming die 22 forms the final shape of the intermediate formed product Fi so that a second cross-sectional area reduction ratio, which represents the ratio of the cross-sectional area of ​​the final formed product Ff to the cross-sectional area of ​​the intermediate formed product Fi along a direction perpendicular to the forming direction, is 10% to 40%, in a forming target portion where the final shape (see FIG. 7) is formed for the intermediate formed product Fi. To this end, the second forming die 22 has a guide part 221 arranged rearward in the forming direction (upward in the vertical direction in this embodiment), and a forming space 222 arranged forward in the forming direction relative to the guide part 221 (downward in the vertical direction in this embodiment), as shown in FIG.

[0031] The guide portion 221 has a guide portion 221A that is provided on the inner peripheral surface along the axial direction so as to fit with the temporary external teeth M4 formed on the side portion M2 of the intermediate formed product Fi that advances forward in the forming direction (downward in the vertical direction), and that guides the intermediate formed product Fi into the forming space 222. The forming space 222 has a forming portion 222A that is provided on the inner peripheral surface along the axial direction so as to form spur teeth M5 (see FIG. 7) that are parallel to the rotation axis of the final formed product Ff, i.e., the product W, by applying drawing as cold forging to the temporary external teeth M4 of the intermediate formed product Fi.

[0032] 5, the inner diameter dimension D2 of the guide portion 221A of the guide portion 221 of the second forming die 22 is set to be slightly larger than the inner diameter dimension D1 (see FIG. 4) of the forming portion 211A of the guide portion 211 of the first forming die 21. Also, as shown in FIG. 5, the inner diameter dimension D3 of the forming space 222 of the second forming die 22 is set to be smaller than the inner diameter dimension D1 of the forming space 212 of the first forming die 21. The inner diameter dimension D3 of the forming space 222 is set so that the second cross-sectional area reduction rate of the side portion M2 of the material M falls within the above-mentioned range of 10% to 40%.

[0033] As a result, when the provisional external tooth M4 of the intermediate formed product Fi is pressed into the second forming die 22, first, the guide portion 221A of the guide portion 221 engages with the provisional external tooth M4 and guides the provisional external tooth M4 toward the forming space 222. Then, the forming portion 222A of the forming space 222 performs drawing on the provisional external tooth M4 that has been guided and entered the forming space 222, forming the spur tooth M5, which is the final shape.

[0034] 1, in the forging apparatus 10 of this embodiment, a first forming die 21 and a second forming die 22 are arranged in series along the forming direction (vertical direction). That is, in the forging apparatus 10, the material M is pressed into the first forming die 21 by the punch 11, and then pressed into the second forming die 22 by the punch 11. As a result, the material M is successively formed with the provisional outer teeth M4 and the spur teeth M5.

[0035] Here, assuming a situation in which the front end of the intermediate formed product Fi during cold forging enters the second forming die 22 and the rear end thereof passes through the first forming die 21, both the forming load of the provisional outer teeth M4 formed by the first forming die 21 and the forming load of the spur teeth M5 formed by the second forming die 22 act on the punch 11. Furthermore, as described above, because the inner diameter D3 of the second forming die 22 is smaller than the inner diameter D1 of the first forming die 21, material flow occurs rearward in the forming direction, which may cause the intermediate formed product Fi to be upset into the first forming die 21. In this case, the forming load increases, which may affect the life of the first forming die 21 and other dies.

[0036] 1, the forging apparatus 10 is provided with a spacer 23 so that the first forming die 21 and the second forming die 22 are spaced apart from each other in the forming direction. Specifically, the spacer 23 separates the first forming die 21 and the second forming die 22 by a distance greater than the axial dimension of the intermediate formed product Fi (material M), i.e., the thickness dimension of the intermediate formed product Fi (material M). As a result, the spacer 23 can prevent a situation from occurring in which the front of the intermediate formed product Fi during cold forging enters the second forming die 22 and the rear of the intermediate formed product Fi passes through the first forming die 21 in the forming direction, thereby suppressing an increase in the forming load.

[0037] In this embodiment, as will be described later, a case will be exemplified in which two blanks M are inserted through the mandrel 12 and then forced into the first forming die 21 and the second forming die 22 to be subjected to cold forging. Therefore, in this embodiment, the spacer 23 separates the first forming die 21 and the second forming die 22 by a distance greater than the thickness dimension of the two intermediate formed products Fi (blanks M).

[0038] Next, a forging method using the above-described forging apparatus 10 and forming die 20 will be described. In the forging method of this embodiment, as described above, the first forming die 21 is disposed rearward in the forming direction (vertically upward) of the forging apparatus 10, and the second forming die 22 is disposed forward of the first forming die 21 in the forming direction via the spacer 23. In other words, the first forming die 21 and the second forming die 22 are attached so as to be in series along the forming direction. The forging method uses the forging apparatus 10 to successively perform a first forging step in which the side portion M2 of the material M is cold forged to form an intermediate formed product Fi, and a second forging step in which the intermediate formed product Fi is cold forged to form a final formed product Ff, i.e., a product W.

[0039] 1, two raw materials M (hereinafter, to distinguish between the two raw materials M, one raw material M will be referred to as "raw material MA" and the other raw material M will be referred to as "raw material MB") inserted into a mandrel 12 are pressed into a first forming die 21 and a second forming die 22. That is, in the forging method, in the first forging step, the raw materials MA and MB are pressed into the first forming die 21 to form two intermediate formed products FiA and FiB, and in the second forging step, the intermediate formed products FiA and FiB are pressed into the second forming die 22 to form two final formed products FfA and FfB, i.e., two pinion gears W.

[0040] In the first forging step, first, with the raw material MA set so as to abut against the holding portion 211A of the guide portion 211 of the first forming die 21, the drive unit 13 transmits a driving force to the punch 11 toward the front in the forming direction (downward in the vertical direction). As a result, the punch 11 advances in the forming direction (downward in the vertical direction) together with the mandrel 12, and pushes the raw material MA guided by the holding portion 211A into the forming space 212 via the raw material MB located behind it in the forming direction. Furthermore, as the punch 11 advances in the forming direction (downward in the vertical direction) together with the mandrel 12, the raw material MB comes into contact with the holding portion 211A of the guide portion 211 of the first forming die 21.

[0041] 6 are formed on the side portion M2 of the blank MA pressed into the forming space 212 while the blank MA moves relative to the forming portion 212A of the forming space 212. In other words, by undergoing the first forging step, the blank MA located at the front in the forming direction is formed as an intermediate formed product FiA having the temporary external teeth M4 on the side portion M2.

[0042] The intermediate product FiA is further advanced in the forming direction (downward in the vertical direction) by the punch 11 and ejected from the forming space 212 of the first forming die 21, thereby completing the first forging step of the intermediate product FiA. After the first forging step is completed, the intermediate product FiA is further advanced in the forming direction (downward in the vertical direction) by the punch 11, passes through the spacer 23, and reaches the second forming die 22.

[0043] On the other hand, the blank MB, which is positioned behind the blank MA in the forming direction, is pushed into the forming space 212 by the punch 11 while the blank MA is passing through the forming space 212 of the first forming die 21. That is, in the first forging process, the blank MB moves relative to the forming portion 212A of the forming space 212 while pushing the preceding blank MA from rear to front in the forming direction.

[0044] 6 is formed on the side portion M2 of the raw material MB that has been pressed into the forming space 212 while moving relative to the forming portion 212A of the forming space 212 while pushing the raw material MA. In other words, by undergoing the first forging step, the raw material MB that is located behind the raw material MA in the forming direction is formed as an intermediate formed product FiB that has the temporary external teeth M4 on the side portion M2.

[0045] The intermediate product FiB is further advanced in the forming direction (downward in the vertical direction) by the punch 11 and ejected from the forming space 212 of the first forming die 21, completing the first forging step of the intermediate product FiB. After the first forging step is completed, the intermediate product FiB is further advanced in the forming direction (downward in the vertical direction) by the punch 11 and passes through the spacer 23, pressing the intermediate product FiA against the second forming die 22.

[0046] When the intermediate product FiA passes through the spacer 23 and reaches the second forming die 22, a second forging process is performed on the intermediate product FiA. In the second forging process, the punch 11 of the forging device 10 moves forward in the forming direction (downward in the vertical direction) and pushes the intermediate product FiA into the guide portion 221 of the second forming die 22. As a result, the guide portion 221A of the guide portion 221 engages with the temporary outer teeth M4 of the intermediate product FiA and guides the temporary outer teeth M4 toward the forming space 222.

[0047] The punch 11 then presses the provisional outer teeth M4 of the intermediate formed product FiA into the forming space 222 of the second forming die 22 via the intermediate formed product FiB located behind it in the forming direction. As a result, the provisional outer teeth M4 are drawn while moving relative to the forming portion 222A of the forming space 222, thereby forming spur teeth M5 as shown in FIG. 7. In other words, through the second forging step, a final formed product FfA, i.e., a pinion gear W, having the spur teeth M5, which is the final shape, is formed. Then, as the punch 11 further advances in the forming direction (descending vertically), the final formed product FfA is ejected from the forming space 222 of the second forming die 22, and the second forging step is completed.

[0048] On the other hand, when the intermediate product FiB, which is located rearward of the intermediate product FiA in the forming direction, passes through the spacer 23 and reaches the second forming die 22, the second forging step is executed. In the second forging step, the punch 11 of the forging device 10 moves forward in the forming direction (downward in the vertical direction), and the intermediate product FiB is pushed into the guide portion 221 of the second forming die 22 while pressing the intermediate product FiA. As a result, the guide portion 221A of the guide portion 221 engages with the temporary outer teeth M4 of the intermediate product FiB and guides the temporary outer teeth M4 toward the forming space 222.

[0049] Then, the punch 11 presses the provisional outer teeth M4 of the intermediate molded product FiB together with the provisional outer teeth M4 of the preceding intermediate molded product FiA into the molding space 222 of the second molding die 22. As a result, while the intermediate molded product FiB presses the intermediate molded product FiA, the provisional outer teeth M4 of the intermediate molded product FiB move relatively to the molding portion 222A of the molding space 222, and drawing is performed on the provisional outer teeth M4, thereby forming spur teeth M5 as shown in FIG.

[0050] That is, by passing through the second forging step, a final formed product FfB having spur teeth M5, which is the final shape, i.e., a pinion gear W, is formed. Then, similar to the final formed product FfA, the final formed product FfB is ejected from the forming space 222 of the second forming die 22 by the punch 11 further advancing in the forming direction (moving down in the vertical direction), and the second forging step is completed.

[0051] Here, in the first forging process and the second forging process, the raw material MA preceding the raw material MB has nothing in front of it in the forming direction, so it is not subjected to back pressure when it passes through the forming space 212 of the first forming die 21 and the forming space 222 of the second forming die 22, i.e., during cold forging. However, the raw material MB pushing the raw material MA from behind is subjected to back pressure from the preceding raw material MA when it passes through the forming space 212 of the first forming die 21 and the forming space 222 of the second forming die 22, i.e., during cold forging.

[0052] In this case, even if the inner diameter dimensions D1 and D3 are set so that the cross-sectional area reduction rate is 10% to 40% and an increase in the forming load is suppressed as described above, when back pressure is applied from the front in the forming direction, the axially diverted material flow generated in the blank MB will preferentially occur rearward in the forming direction, i.e., toward the punch 11. As a result, in the blank MB subjected to back pressure, excess portions M6 such as burrs will occur on the contact side with the punch 11, as shown in Figures 8, 9, and 10. In particular, the excess portions M6 are likely to occur in the small diameter portion that is drawn by the forming portion 212A of the first forming die 21 and the forming portion 222A of the second forming die 22, as shown in Figure 9.

[0053] Incidentally, the punch 11 is provided with a storage portion 112 in the small diameter portion 111 at the end on the contact side that comes into contact with the raw material MB, for storing the surplus portion M6. The generated surplus portion M6 is stored in the storage portion 112 provided at the rear in the forming direction, as shown in Fig. 8. As a result, the surplus portion M6 stored in the storage portion 112 is not cut off at the fitting portions between the punch 11 and the first forming die 21 and the second forming die 22 as shown in Fig. 11.

[0054] 10, the uncut excess portion M6 is finally discharged outside the second forming die 22 together with the product W. As a result, even when the product W is continuously forged, the excess portion M6 is prevented from remaining inside the first forming die 21 and the second forming die 22 in the first forging process and the second forging process. This eliminates the need for a separate removal process, and even if a removal process is provided, the frequency of such a process can be reduced. The excess portion M6 discharged together with the product W without being cut is removed, for example, by cutting in a subsequent process after forging.

[0055] As can be understood from the above description, the forging device 10 includes a forming die 20 that forges the material M, and a punch 11 that pushes the material M toward the forming die 20, which is disposed forward in the forming direction, and the punch 11 has a receiving portion 112 at the end of the contact side that contacts the material M, for receiving a surplus portion M6 that is generated in the material M due to a divergence of the material flow generated in the material M during forging toward the rear in the forming direction. In this case, the punch 11 pushes multiple materials MA and MB toward the forming die 20.

[0056] In this case, the accommodation portion 112 is provided to extend along the molding direction. More specifically, the accommodation portion 112 is provided to extend along the direction in which the excess portion M6 is generated.

[0057] In this case, the forming die 20 forms the outer surfaces M2 of the materials MA, MB by dividing the material flow in the materials MA, MB along a direction perpendicular to the forming direction.

[0058] In this case, the forming die 20 forms the side portions M2, which are the outer surfaces of the materials MA and MB, by dividing the material flow that occurs in the materials MA and MB during forging along a direction perpendicular to the forming direction, for the materials MA and MB, which have outer dimensions Dm (outer diameter dimension Dm) smaller than the outer dimensions Df (outer diameter dimension Df) of the pinion gear W after forging, and includes a first forming die 21 that forms intermediate formed products FiA and FiB having an intermediate shape from the materials MA and MB, and a second forming die 22 that forms final formed products FfA and FfB, which have a final shape with outer dimensions (outer diameter dimension) smaller than the outer dimensions (outer diameter dimension) of the intermediate shape, from the intermediate formed products FiA and FiB.

[0059] In this case, the first forming die 21 forms an intermediate shape for the materials MA, MB so that a first area reduction ratio, which represents the ratio of the cross-sectional area of ​​the intermediate formed products FiA, FiB to the cross-sectional area of ​​the materials MA, MB along a direction perpendicular to the forming direction in the forming target portion where the intermediate shape is to be formed for the materials MA, MB, is 10% to 40%, and the second forming die 22 forms a final shape for the intermediate formed products FiA, FiB so that a second area reduction ratio, which represents the ratio of the cross-sectional area of ​​the final formed products FfA, FfB to the cross-sectional area of ​​the intermediate formed products FiA, FiB along a direction perpendicular to the forming direction in the forming target portion where the final shape is to be formed for the intermediate formed products FiA, FiB, is 10% to 40%.

[0060] Also, the forging method for forging materials MA, MB using these forging devices 10 includes a first forging process for forging the materials MA, MB using a first forming die 21 to form intermediate formed products FiA, FiB from the materials MA, MB, and a second forging process for forging the intermediate formed products FiA, FiB using a second forming die 22 to form final formed products FfA, FfB from the intermediate formed products FiA, FiB.

[0061] According to the forging apparatus 10, the receiving portion 112 of the punch 11 can receive the excess portion M6 generated during forging. This prevents the excess portion M6 from being cut off during forging, and as a result, the resulting excess portion M6 is ejected from the second forming die 22 of the forming die 20 together with the materials MA and MB, more specifically, the final formed products FfA and FfB, and the pinion gear W after forging. This prevents the excess portion M6 from remaining inside the forming die 20, i.e., the first forming die 21 and the second forming die 22, during the forging process, even when the pinion gear W is continuously forged. This eliminates the need for a separate removal process. Therefore, when the forging apparatus 10 is used, in other words, when a forging method using the forging apparatus 10 is used, the production efficiency of forging can be improved.

[0062] The present invention is not limited to the above-described embodiment, but can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0063] For example, in the above-described embodiment, the forging apparatus 10 is used to form a pinion gear W having spur teeth M5 parallel to the rotation axis from the raw material M. However, it is also possible to form spiral helical teeth from the raw material M using the forging apparatus 10. In this case, the receiving portion provided in the haunch 11 is provided, for example, so as to be aligned with the tooth ridge of the helical teeth and form a spiral helical shape relative to the axis of the punch 11. As a result, even if excess portions such as burrs are generated during the formation of the helical teeth, the receiving portion can receive the excess portions, as in the above-described embodiment. Therefore, in this case as well, the same effects as in the above-described embodiment can be obtained.

[0064] In the above-described embodiment, a pinion gear W is formed using an annular material M as the workpiece. However, examples of the workpiece include a cross-sectional shape perpendicular to the axial direction, such as a disk shape or a polygonal shape. Examples of the product include a gear, a spline shaft, a key groove, a key, etc. Furthermore, the "external dimension" corresponds to the "external diameter dimension" when the cross-sectional shapes of the material and the product are disk-shaped or annular, and corresponds to the "width dimension" when the cross-sectional shapes of the material M and the product W are polygonal.

[0065] Here, the forging forming device of the first form of the present invention comprises a forming die that performs forging on a material, and a punch that pushes the material toward the forming die that is positioned forward in the forming direction, and the punch has a storage portion at the end on the contact side that abuts the material, for storing excess material that is generated in the material due to the material flow that occurs in the material during forging being diverted toward the rear in the forming direction.

[0066] A forging apparatus according to a second aspect of the present invention is the forging apparatus according to the first aspect, wherein the accommodating portion extends along the forming direction.

[0067] A forging apparatus according to a third aspect of the present invention is the forging apparatus according to the second aspect, wherein the accommodation portion extends along the direction in which the excess portion is generated.

[0068] Furthermore, a fourth form of the forging device of the present invention is a forging device of any one of the first to third forms, in which the forming die forms the outer surface of the material by dividing the material flow in the material along a direction perpendicular to the forming direction.

[0069] Furthermore, a fifth form of the forging forming apparatus of the present invention is the forging forming apparatus of the fourth form described above, in which the forming die forms the outer surface of a material having an outer dimension smaller than the outer dimension after forging by diverting the material flow that occurs in the material during forging along a direction perpendicular to the forming direction, and includes a first forming die that forms an intermediate formed product having an intermediate shape from the material, and a second forming die that forms a final formed product from the intermediate formed product having a final shape with an outer dimension smaller than the outer dimension of the intermediate shape.

[0070] In addition, a sixth form of the forging device of the present invention is the forging device of the fifth form described above, in which the first forming die forms an intermediate shape for the material so that a first area reduction rate, which represents the ratio of the cross-sectional area of ​​the intermediate formed product to the cross-sectional area of ​​the material along a direction perpendicular to the forming direction in the forming target portion where the intermediate shape is formed for the material, is 10% to 40%, and the second forming die forms a final shape for the intermediate formed product so that a second area reduction rate, which represents the ratio of the cross-sectional area of ​​the final formed product to the cross-sectional area of ​​the intermediate formed product along a direction perpendicular to the forming direction in the forming target portion where the final shape is formed for the intermediate formed product, is 10% to 40%.

[0071] A forging apparatus according to a seventh aspect of the present invention is the forging apparatus according to any one of the first to sixth aspects, wherein the punch pushes a plurality of materials toward the forming die.

[0072] Furthermore, the forging method of the present invention is a forging method for forging a raw material using a forging device of any one of the first to seventh embodiments, and includes a first forging process for forging the raw material to form an intermediate product from the raw material, and a second forging process for forging the intermediate product to form a final product from the intermediate product. [Explanation of symbols]

[0073] 10...Forging device, 11...Punch, 111...Small diameter portion, 112...Containing portion, 12...Mandrel, 13...Driver, 14...Table, 15...Pressure plate, 20...Forming die, 21...First forming die, 211...Guide portion, 211A...Holding portion, 212...Forming space, 212A...Forming portion, 22...Second forming die, 221...Guide portion, 221A...Guide portion, 222...Forming space, 222A...Forming portion, 23...Spacer, M...Material, M6...Excess portion, Fi...Intermediate formed product, Ff...Final formed product, W...Pinion gear, P...Punch, S...Forming die, Mw...Excess portion

Claims

1. a forming die for forging the material; a punch that pushes the material toward the forming die that is disposed forward in the forming direction, The punch A forging device having a storage section at the end of the contact side that contacts the material, which stores excess material generated in the material due to a diversion of material flow generated in the material during the forging process toward the rear in the forming direction.

2. The storage section is The forging device according to claim 1 , which is provided extending along the forming direction.

3. The storage section is The forging device according to claim 2 , wherein the forging device extends along a direction in which the excess portion is generated.

4. The forming die The forging device according to claim 1 , wherein the outer surface of the blank is shaped by dividing the material flow in the blank along a direction perpendicular to the shaping direction.

5. The forming die For the material having an outer dimension smaller than the outer dimension after the forging, the outer surface of the material is shaped by a branch flow of the material flow that occurs in the material due to the forging along a direction perpendicular to the forming direction, a first forming die for forming an intermediate product having an intermediate shape from the material; and a second forming die for forming a final shape from the intermediate shape, the final shape having an outer dimension smaller than that of the intermediate shape.

6. The first forming die forming the intermediate shape on the raw material so that a first cross-sectional area reduction rate, which represents a ratio of a cross-sectional area of ​​the intermediate molded product to a cross-sectional area of ​​the raw material along a direction perpendicular to the molding direction, is 10% to 40% in a molding target portion where the intermediate shape is formed on the raw material; The second forming die 6. The forging device according to claim 5, wherein the final shape is formed on the intermediate formed product so that a second area reduction ratio, which represents a ratio of a cross-sectional area of ​​the final formed product to a cross-sectional area of ​​the intermediate formed product along a direction perpendicular to the forming direction, is 10% to 40% in a forming target portion where the final shape is formed on the intermediate formed product.

7. The punch The forging device according to claim 1 , wherein a plurality of the blanks are forced toward the forming die.

8. A forging method for forging the material using the forging device according to any one of claims 1 to 7, a first forging step of forging the material to form the intermediate product from the material; a second forging step of forging the intermediate product to form the final product from the intermediate product.

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