Forging molds
The forging die design addresses reduced forming surface areas and rigidity issues by using concave molding portions and horizontally recessed fixing grooves, ensuring minimal groove depth and specific distance ratios, resulting in increased rigidity and durability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-08-28
- Publication Date
- 2026-04-02
AI Technical Summary
The existing forging dies suffer from reduced forming surface areas due to recesses for fixing members, limiting the size of molded products and compromising die rigidity.
A forging die design with vertically movable dies featuring concave molding portions and horizontally recessed fixing grooves, allowing for a larger forming surface area and increased rigidity by ensuring the groove depth is minimal relative to the molding surface length and maintaining specific distance ratios.
The design secures a larger forming surface area, enhances die rigidity, and prevents stress concentration, thereby enabling wider concave forming portions and improved durability.
Smart Images
Figure 0007839771000001 
Figure 0007839771000002 
Figure 0007839771000003
Abstract
Description
Technical Field
[0001] The present invention relates to a forging die.
Background Art
[0002] The forging die of Patent Document 1 includes a lower die having a lower forming surface, an upper die having an upper forming surface facing the lower die, a bolster abutting against the lower surface of the lower die, and a lower holder fixed to the bolster. The side surface of the lower die has a recess recessed inward from the side surface, and the recess extends from the center in the height direction of the lower die to the lower forming surface. The lower die is fixed to the lower bolster by engaging a fixing member provided on the upper part of the lower holder with the upper part of the recess.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the forging die of Patent Document 1, the lower die is biased downward and fixed to the lower bolster by engaging a fixing member with a recess extending to the lower forming surface. Therefore, there is a problem that the area of the lower forming surface is reduced by the area of the recess, and accordingly, the size of the molded product that can be molded on the lower forming surface is reduced. The upper die is biased upward and fixed to the upper bolster by engaging a fixing member with a recess extending to the upper forming surface. Therefore, there is a problem that the area of the upper forming surface is reduced by the area of the recess. Further, even in a configuration in which the side surface of the lower die has a trapezoidal shape tapered upward (toward the lower forming surface) and the side surface of the upper die has a trapezoidal shape tapered downward (toward the upper forming surface), there is a problem that the area of each of the upper forming surface and the lower forming surface is reduced.
[0005] The present invention aims to solve the problems described above. [Means for solving the problem]
[0006] An aspect of the present invention is a forging die comprising a lower die and an upper die that is movable vertically relative to the lower die, wherein each of the first die, which is one of the lower die and the upper die, and the second die, which is the other of the lower die and the upper die, has a molding surface, the molding surface of the first die and the molding surface of the second die face each other, and each of the first die and the second die is fixed to a holder by a fixing member, wherein at least the first die comprises a concave molding portion recessed in relation to the molding surface in accordance with the shape of the molded product, a holding surface that abuts against the support surface of the holder intersecting the direction of movement of the upper die, and a side surface connecting the outer edge of the molding surface and the outer edge of the holding surface, wherein the side surface comprises a first side surface portion connected to the outer edge of the molding surface, a second side surface portion connected to the outer edge of the holding surface, and a fixing groove portion provided between the first side surface portion and the second side surface portion, recessed horizontally relative to the first side surface portion and the second side surface portion, into which the fixing member engages. [Effects of the Invention]
[0007] According to the present invention, in a forging die, the first side portion connected to the outer edge of the forming surface protrudes horizontally beyond the fixing groove portion. Therefore, compared to a configuration in which the fixing groove portion for engaging the fixing member extends to the forming surface, and a configuration in which the lower and upper dies are formed in a trapezoidal shape that tapers toward the forming surface, a larger area of the forming surface of the first die can be secured. As a result, the rigidity of at least the first die can be increased, and consequently, it becomes possible to form a wider concave forming portion on the forming surface. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 is an overall cross-sectional view showing a forging die according to an embodiment of the present invention. [Figure 2] Figure 2 is an overall diagram showing the upper die of the forging die shown in Figure 1 in an open state. [Figure 3]Figure 3 is a plan view of the lower mold as seen from the first molding surface. [Figure 4] Figure 4 is an enlarged cross-sectional view showing the vicinity of the side surface of the first end of the lower mold shown in Figure 2. [Figure 5] Figure 5 is a characteristic diagram showing the relationship between the stress generated on the side surface during molding of a molded product and the ratio of the groove depth of the fixing groove to the length of the molded surface. [Figure 6] Figure 6 is a plan view of the upper mold as seen from the second molding surface. [Figure 7] Figure 7 is an enlarged cross-sectional view showing the vicinity of the side surface of the second end of the upper mold shown in Figure 6. [Figure 8] Figure 8A is an enlarged cross-sectional view showing the case where the first molding surface of the lower mold has been resynced. Figure 8B is an enlarged cross-sectional view showing the case where the second molding surface of the upper mold has been resynced. [Figure 9] Figure 9 is a characteristic diagram showing the relationship between the stress generated on the side surface of a molded product during molding and the ratio of the first distance to the second distance. [Modes for carrying out the invention]
[0009] As shown in Figure 1, the forging die 10 according to this embodiment comprises a first die 121, a second die 122 facing the first die 121, a holder 14, and fixing members 161 and 162. The forging die 10 obtains a molded product C (see Figure 2) by closing the die by bringing the first die 121 and the second die 122 close together. As shown in Figure 2, the molded product C is, for example, a crankshaft used in an internal combustion engine. However, the molded product C is not limited to being a crankshaft.
[0010] As shown in Figure 1, the first mold 121 is either the lower mold 18 or the upper mold 20 positioned above the lower mold 18. The second mold 122 is the other of the lower mold 18 or the upper mold 20. The following description will focus on the case where the first mold 121 is the lower mold 18 positioned at the bottom of the forging die 10, and the second mold 122 is the upper mold 20 positioned above the lower mold 18. The first mold 121 is referred to as the lower mold 18, and the second mold 122 is referred to as the upper mold 20. The lower mold 18 and the upper mold 20 are formed from a metal material (for example, alloy tool steel).
[0011] As shown in Figure 3, the lower mold 18 is formed in a rectangular shape that is elongated in one direction and shorter in a direction perpendicular to that direction. Hereinafter, the shorter direction of the lower mold 18 will be referred to as the width direction. As shown in Figure 2, the lower mold 18 includes a first molding surface 221 (also called "molding surface 22"), a first holding surface 241 (also called "holding surface 24"), a first outer peripheral surface 261, a first concave molding portion 281 (also called "concave molding portion 28"), and a first fixing groove portion 301 (also called "fixing groove portion 30").
[0012] The first molding surface 221 is formed on the upper part of the lower mold 18. The first molding surface 221 is the surface facing the upper mold 20. The first molding surface 221 extends in a direction perpendicular to the direction of movement of the upper mold 20. The first holding surface 241 is provided on the lower part of the lower mold 18. The first holding surface 241 extends in the horizontal direction. The first holding surface 241 abuts against the holder 14.
[0013] As shown in Figure 3, the first outer peripheral surface 261 is annular in shape, surrounding the side of the lower mold 18. The first outer peripheral surface 261 has a plurality of side surfaces 321. The plurality of side surfaces 321 connect the outer edge of the first molding surface 221 and the outer edge of the first holding surface 241. The plurality of side surfaces 321 extend vertically along the outer edge of the lower mold 18 (see Figure 2). Of the plurality of side surfaces 321, two first end side surfaces 34, each equipped with a first fixing groove 301, are provided at one end and the other end in the longitudinal direction of the lower mold 18.
[0014] As shown in FIG. 2, the first end side surface 34 includes a first side surface portion 341 and a second side surface portion 342. The first side surface portion 341 is provided at the upper part of the side surface 321. The first side surface portion 341 is continuous with the outer edge portion of the first forming surface 221. The first side surface portion 341 extends in the width direction, which is a horizontal direction orthogonal to the moving direction of the upper mold 20 (see FIG. 3). The second side surface portion 342 is provided at the lower part of the side surface 321. The second side surface portion 342 is continuous with the outer edge portion of the first holding surface 241.
[0015] The first concave forming portion 281 is formed by being recessed downward with respect to the first forming surface 221. The first concave forming portion 281 is formed corresponding to the shape of the molded product C. The first concave forming portion 281 has a plurality of first concave forming grooves 36. The plurality of first concave forming grooves 36 are arranged along the longitudinal direction of the lower mold 18.
[0016] The first concave forming groove 36 includes a set of first end forming grooves 38. In the plurality of first concave forming grooves 36, the first end forming grooves 38 are arranged at one end and the other end of the lower mold 18. In the plurality of first concave forming grooves 36, the set of first end forming grooves 38 are arranged closest to the first end side surface 34.
[0017] As shown in FIG. 3, in the width direction of the lower mold 18, the width W1 of the first side surface portion 341 is not less than the maximum width W2 of the first concave forming portion 281 (W1 ≧ W2).
[0018] As shown in FIG. 2, the first fixing groove portion 301 is provided on the first end side surface 34 of the lower mold 18. A fixing member 161 can be engaged with the first fixing groove portion 301. The first fixing groove portion 301 is provided between the first side surface portion 341 and the second side surface portion 342. The first fixing groove portion 301 is recessed in the horizontal direction with respect to the first side surface portion 341 and the second side surface portion 342. As shown in FIG. 4, the first fixing groove portion 301 has a dimension in the vertical direction larger than the groove depth D1 in the horizontal direction along the longitudinal direction of the lower mold 18. The first fixing groove portion 301 has a bottom portion 40. In the groove depth direction of the first fixing groove portion 301, the bottom portion 40 is arranged to be most separated from the first end side surface 34. The bottom portion 40 and the side surface 321 are substantially parallel. That is, the bottom portion 40 extends along the vertical direction. The groove depth direction of the first fixing groove portion 301 is orthogonal to the first side surface portion 341.
[0019] The first fixing groove portion 301 has a groove depth D1 in the horizontal direction. In the longitudinal direction of the lower mold 18, the groove depth D1 is the distance between the side surface 321 (the first side surface portion 341) and the bottom portion 40. The shortest distance from the first end forming groove 38 to the side surface 321 (the first side surface portion 341) is the forming surface length L1. The relationship between the groove depth D1 and the forming surface length L1 of the first fixing groove portion 301 will be described with reference to FIG. 5. FIG. 5 shows the relationship between the stress P generated on the side surface 321 (the first side surface portion 341) when the molded product C is molded by the forging die 10, and the ratio of the groove depth D1 to the forming surface length L1. As the ratio (D1 / L1) of the groove depth D1 to the forming surface length L1 increases, the stress P generated on the side surface 321 increases. When the threshold value of the stress P generated during molding is 1350 MPa, it is possible to maintain the stress P below the threshold value (1350 MPa) by satisfying the relationship of D1 / L1≤0.229. That is, it is preferable to satisfy the relationship of D1 / L1≤0.229.
[0020] In the groove depth direction of the first fixing groove 301, the height E1 of the first side surface 341 relative to the bottom 40 and the height E2 of the second side surface 342 relative to the bottom 40 are the same. However, the heights E1 of the first side surface 341 and E2 of the second side surface 342 may be different. If the heights E1 and E2 are different, the height E1 of the first side surface 341 relative to the bottom 40 should be at least half the height E2 of the second side surface 342 relative to the bottom 40.
[0021] In the direction of movement of the upper mold 20, it is preferable that the first distance H1, which is the distance between the end portion 341a of the first side portion 341 that is furthest from the first molding surface 221 and the first molding surface 221, and the second distance H2, which is the distance from the first molding surface 221 to the deepest part 381 of the first end molding groove 38, satisfy the relationship H1 ≥ H2.
[0022] The first fixing groove 301 further includes a first engaging end 421. The first engaging end 421 is provided at the lower part of the first fixing groove 301. The first engaging end 421 is the end into which the fixing member 161 is engaged. The first engaging end 421 and the bottom portion 40 are substantially perpendicular to each other.
[0023] As shown in Figure 2, the upper mold 20 is positioned above the lower mold 18. The upper mold 20 includes a second molding surface 222, a second holding surface 242, a second outer peripheral surface 262, a second concave molding portion 282, and a second fixing groove portion 302.
[0024] The second molding surface 222 is formed on the lower part of the upper mold 20 and faces the first molding surface 221 of the lower mold 18. The second molding surface 222 extends in a direction perpendicular to the direction of movement of the upper mold 20.
[0025] The second retaining surface 242 is provided on the upper part of the upper mold 20. The second retaining surface 242 extends horizontally. The second retaining surface 242 abuts against the holder 14.
[0026] As shown in Figure 6, the second outer peripheral surface 262 is annular in shape, surrounding the side of the upper mold 20. The second outer peripheral surface 262 has a plurality of side surfaces 322. As shown in Figure 2, the plurality of side surfaces 322 connect the outer edge of the second molding surface 222 and the outer edge of the second holding surface 242. The plurality of side surfaces 322 extend vertically along the outer edge of the upper mold 20. Of the plurality of side surfaces 322, two second end side surfaces 44, each equipped with a second fixing groove 302, are provided at one end and the other end in the longitudinal direction of the upper mold 20.
[0027] As shown in Figure 7, the second end side surface 44 comprises a first side surface portion 441 and a second side surface portion 442. The first side surface portion 441 is provided at the lower part of the side surface 322. The first side surface portion 441 is connected to the outer edge of the second molding surface 222. The first side surface portion 441 extends in the width direction, which is the horizontal direction perpendicular to the direction of movement of the upper mold 20. The second side surface portion 442 is provided at the upper part of the side surface 322. The second side surface portion 442 is connected to the outer edge of the second holding surface 242.
[0028] As shown in Figure 2, the second concave molding section 282 is formed as a recess that is recessed upward relative to the second molding surface 222. The second concave molding section 282 is formed in accordance with the shape of the molded product C. The second concave molding section 282 faces the first concave molding section 281 of the lower mold 18. The second concave molding section 282 has a plurality of second concave molding grooves 46. The plurality of second concave molding grooves 46 are arranged along the longitudinal direction of the upper mold 20. When the lower mold 18 and the upper mold 20 are closed, a cavity is formed by the first concave molding section 281 and the second concave molding section 282. The molded product C is formed by the first concave molding section 281 of the lower mold 18 and the second concave molding section 282 of the upper mold 20.
[0029] As shown in Figure 6, the second concave molding groove 46 includes a pair of second end molding grooves 48. In multiple second concave molding grooves 46, the second end molding grooves 48 are located at one end and the other end of the upper mold 20. In multiple second concave molding grooves 46, a pair of second end molding grooves 48 is located closest to the second end side surface 44. In the width direction of the upper mold 20, the width W1 of the first side surface portion 441 is greater than or equal to the maximum width W2 of the second concave molding portion 282 (W1 ≧ W2).
[0030] As shown in Figure 2, the second fixing groove 302 is provided on the second end side surface 44 of the upper mold 20. A fixing member 162 can engage with the second fixing groove 302. The second fixing groove 302 is provided between the first side surface 441 and the second side surface 442. The second fixing groove 302 is recessed horizontally relative to the first side surface 441 and the second side surface 442. As shown in Figure 7, the vertical dimension of the second fixing groove 302 is greater than the horizontal groove depth D2, which is in the longitudinal direction of the upper mold 20. The second fixing groove 302 has a bottom portion 40. In the groove depth direction of the second fixing groove 302, the bottom portion 40 is positioned furthest from the second end side surface 44. The bottom portion 40 and the side surface 322 are substantially parallel. That is, the bottom portion 40 extends along the vertical direction. The groove depth direction of the second fixing groove 302 is perpendicular to the first side surface 441.
[0031] The second fixing groove 302 has a groove depth D2 in the horizontal direction. In the longitudinal direction of the upper mold 20, the groove depth D2 is the distance between the side surface 322 and the bottom 40. The distance from the second end molding groove 48 to the second end side surface 44 is the molding surface length L2. In this case, it is preferable that the groove depth D2 of the second fixing groove 302 and the molding surface length L2 satisfy the relationship D2 / L2 ≤ 0.229. If the threshold stress P generated on the side surface 322 during molding is set to 1350 MPa, it is possible to maintain the stress P below the threshold (1350 MPa) by satisfying the relationship D2 / L2 ≤ 0.229. Note that the relationship between the groove depth D2 of the second fixing groove 302 and the molding surface length L2 is the same as the relationship between the groove depth D1 and the molding surface length L1 of the first fixing groove 301 shown in Figure 5, so a detailed explanation is omitted.
[0032] In the groove depth direction of the second fixing groove 302, the height E1 of the first side surface 441 relative to the bottom 40 and the height E2 of the second side surface 442 relative to the bottom 40 are the same. Note that the height E1 of the first side surface 441 relative to the bottom 40 only needs to be at least half the height E2 of the second side surface 442 relative to the bottom 40.
[0033] In the direction of movement of the upper mold 20, it is preferable that the first distance H1, which is the distance between the end portion 441a of the first side portion 441 that is furthest from the second molding surface 222 and the second molding surface 222, and the second distance H2, which is the distance from the second molding surface 222 to the deepest part 481 of the second end molding groove 48, satisfy the relationship H1 ≥ H2.
[0034] The second fixing groove 302 further includes a second engaging end 422. The second engaging end 422 is provided on the upper part of the second fixing groove 302. The second engaging end 422 is the end into which the fixing member 162 is engaged. The second engaging end 422 and the bottom 40 are approximately perpendicular to each other.
[0035] As shown in Figure 1, the holder 14 comprises a lower holder 141 that holds the lower mold 18 and an upper holder 142 that holds the upper mold 20. The lower holder 141 is located below the lower mold 18. The lower holder 141 comprises a first support surface 501 and a first extension 521. The first support surface 501 is the upper surface of the lower holder 141. The first support surface 501 extends horizontally and contacts the first holding surface 241 of the lower mold 18. The first extension 521 extends longitudinally beyond one end and the other end of the lower mold 18 in the longitudinal direction.
[0036] The upper holder 142 is provided above the upper mold 20. The upper holder 142 comprises a second support surface 502 and a second extension 522. The second support surface 502 is the lower surface of the upper holder 142. The second support surface 502 extends horizontally and contacts the second holding surface 242 of the upper mold 20. The second extension 522 extends longitudinally beyond one end and the other end of the upper mold 20 in the longitudinal direction. The upper holder 142 is connected to a pressing mechanism (not shown) and is provided to be displaceable along the vertical direction together with the upper mold 20.
[0037] A pair of fixing members 161 are provided, facing each other at one end and the other end of the lower mold 18. The fixing members 161 face the first fixing groove 301 and extend horizontally. A pair of fixing members 162 are provided, facing each other at one end and the other end of the upper mold 20. The fixing members 162 face the second fixing groove 302 and extend horizontally.
[0038] As shown in Figure 1, each of the fixing members 161 and 162 includes a fixing portion 54 and an engaging portion 56. The fixing portion 54 is provided at one end of the fixing members 161 and 162. As shown in Figure 4, the fixing portion 54 of the fixing member 161 is Lower holder 141 The fixing portion 54 faces the first extension portion 521 and is fixed to the first extension portion 521. The fixing portion 54 is a fixed end that is fixed to the first extension portion 521 by a fastening member 58. The first extension portion 521 and the fixing portion 54 are substantially parallel. The fastening direction of the fixing portion 54 is perpendicular to the extending direction of the first extension portion 521 and the fixing portion 54.
[0039] As shown in Figure 7, the fixing portion 54 of the fixing member 162 is Upper holder 142 The fixing portion 54 faces the second extension portion 522 and is fixed to the second extension portion 522. The fixing portion 54 is a fixed end that is fixed to the second extension portion 522 by the fastening member 58. The second extension portion 522 and the fixing portion 54 are substantially parallel. The fastening direction of the fixing portion 54 is perpendicular to the extending direction of the second extension portion 522 and the fixing portion 54.
[0040] As shown in Figure 1, the engaging portion 56 is provided at the other end of the fixing members 161 and 162. As shown in Figure 4, the engaging portion 56 of the fixing member 161 is inserted into the first fixing groove 301 and engages with the first engaging end 421 by contacting it. The engaging portion 56 is a free end. When the engaging portion 56 of the fixing member 161 engages with the first engaging end 421, the lower mold 18 is clamped between the fixing member 161 and the lower holder 141.
[0041] As shown in Figure 7, the engaging portion 56 of the fixing member 162 is inserted into the second fixing groove 302 and engages with the second engaging end 422 by contacting it. When the engaging portion 56 of the fixing member 162 engages with the second engaging end 422, the upper mold 20 is held between the fixing member 162 and the upper holder 142.
[0042] The fixing groove 30 may be provided in only one of the lower mold 18 or the upper mold 20.
[0043] Next, we will explain the case in which a molded product C is formed using a forging die 10.
[0044] First, as shown in Figure 2, the mold is opened with the upper mold 20 positioned above the lower mold 18, and a material (not shown) is placed in the first concave molding section 281. The upper mold 20 is lowered by a pressing mechanism (not shown), and as shown in Figure 1, the second molding surface 222 of the upper mold 20 and the first molding surface 221 of the lower mold 18 come into contact. A cavity is formed by the second concave molding section 282 of the upper mold 20 and the first concave molding section 281 of the lower mold 18, and forging is performed on the material within the cavity. The material is processed into shapes corresponding to the multiple first concave molding grooves 36 and the multiple second concave molding grooves 46, and a molded product C is formed based on the shapes of the first and second concave molding sections 281 and 282.
[0045] By raising the upper mold 20, the mold is opened and separated from the lower mold 18, and the molded product C is removed, thus completing the forging process of the molded product C.
[0046] As described above, repeated use of the forging die 10 may cause wear on the first forming surface 221 of the lower die 18 and the second forming surface 222 of the upper die 20. In this case, resinking is performed to correct the die shape (first and second concave forming parts 281, 282) by grinding down the first forming surface 221 and the second forming surface 222.
[0047] As shown in Figure 8A, in the rethinking process for the lower die 18, the first molding surface 221 is cut by a predetermined height toward the first holding surface 241 along the direction of movement of the upper die 20. The amount of material removed from the first molding surface 221 is constant along the first molding surface 221. The newly cut first molding surface 221a becomes approximately horizontal. A first concave molding portion 281 with the same shape as before the rethinking process is formed on the first molding surface 221. By cutting the first molding surface 221, the new first molding surface 221a approaches the first holding surface 241 and the first fixing groove portion 301. Therefore, as shown in Figure 4, the first distance H1a from the first molding surface 221a to the end portion 341a of the first side portion 341 before the rethinking process is reduced (H1a
[0048] In the direction of movement of the upper die 20, when the distance between the first molding surface 221a and the end portion 341a of the first side portion 341 is defined as the first distance H1a, and the distance from the first molding surface 221a to the deepest part 381 of the first end molding groove 38 is defined as the second distance H2a, the relationship between the stress P generated on the side portion 321 (first side portion 341) when forming the molded product C with the forging die 10 and the ratio of the first distance H1a to the second distance H2a will be explained with reference to Figure 9. As shown in Figure 9, the larger the ratio of the first distance H1a to the second distance H2a (H1a / H2a), the smaller the stress P generated on the side portion 321. If the threshold stress P generated during molding is set to 1350 MPa, it is possible to maintain the stress P below the threshold (1350 MPa) by satisfying the relationship H1a / H2a ≥ 0.53. That is, it is preferable to satisfy the relationship H1a / H2a ≥ 0.53.
[0049] As shown in Figure 8B, in the rethinking process for the upper die 20, the second molding surface 222 is cut by a predetermined height toward the second holding surface 242 along the direction of movement of the upper die 20. The amount of material removed from the second molding surface 222 is constant along the second molding surface 222. The newly cut second molding surface 222a becomes approximately horizontal. A second concave molding portion 282 with the same shape as before the rethinking process is formed on the second molding surface 222. By cutting the second molding surface 222, the new second molding surface 222a approaches the second holding surface 242 and the second fixing groove portion 302. Therefore, as shown in Figure 7, the first distance H1b from the second molding surface 222a to the end 441a of the first side portion 441 becomes smaller than the first distance H1 from the second molding surface 222 to the end 441a of the first side portion 441 before the rethinking process (H1b
[0050] In the direction of movement of the upper mold 20, when the distance from the second molding surface 222a to the end portion 441a of the first side portion 441 is defined as the first distance H1b, and the distance from the second molding surface 222a to the deepest part 481 of the second end molding groove 48 is defined as the second distance H2b, as shown in Figure 9, the larger the ratio of the first distance H1b to the second distance H2b (H1b / H2b), the smaller the stress P generated on the side portion 322 (first side portion 441). If the threshold stress P generated during molding is set to 1350 MPa, it is possible to maintain the stress P below the threshold (1350 MPa) by satisfying the relationship H1b / H2b ≥ 0.53. In other words, it is preferable to satisfy the relationship H1b / H2b ≥ 0.53.
[0051] This embodiment provides the following effects.
[0052] As shown in Figure 2, the forging die 10 has a first die 121, which is one of the lower die 18 and the upper die 20, and a second die 122, which is the other of the lower die 18 and the upper die 20, each having a first forming surface 221 and a second forming surface 222, with the first forming surface 221 of the first die 121 and the second forming surface 222 of the second die 122 facing each other, and the first die 121 and the second die 122 each being fixed to the holder 14 by fixing members 161 and 162. At least the first die 121 has a side surface 321 connecting the outer edge of the first forming surface 221 and the outer edge of the first holding surface 241, and has a first fixing groove 301 between a first side surface 341 connected to the outer edge of the first forming surface 221 and a second side surface 342 connected to the outer edge of the first holding surface 241. The first fixing groove 301 is recessed horizontally relative to the first side surface 341 and the second side surface 342, and the fixing member 161 is engaged with it.
[0053] In this configuration, the first side portion 341, which is connected to the outer edge of the molding surface 22, protrudes horizontally more than the fixing groove portion 30. Therefore, compared to a configuration in which the fixing groove portion 30 for engaging the fixing members 161 and 162 extends to the molding surface 22, and a configuration in which the lower mold 18 and upper mold 20 are formed in a trapezoidal shape that tapers toward the molding surface 22, a larger area of the molding surface 22 of the first mold 121 can be secured. As a result, the rigidity of the first mold 121 can be increased, and consequently, it becomes possible to form a wider concave molding portion 28 (first concave molding portion 281) on the molding surface 22.
[0054] As shown in Figure 4, the fixing groove portion 30 (first fixing groove portion 301) of the first mold 121 has a groove depth D1 in the horizontal direction, and the first concave molded portion 281 has a first end molding groove 38 closest to the side surface 321 having the fixing groove portion 30. The groove depth D1 of the fixing groove portion 30 and the molding surface length L1, which is the distance from the first end molding groove 38 to the side surface 321, satisfy the relationship D1 / L1 ≤ 0.229 (see Figure 5).
[0055] As a result, by ensuring that the molding surface length L1 of the first mold 121 is secured such that the groove depth D1 of the fixing groove 30 is in a ratio of 0.229 or less to the molding surface length L1, the stress P generated on the side surface 321 having the fixing groove 30 can be effectively suppressed when molding the molded product C. This suppresses cracking of the first mold 121 caused by stress concentration and improves the durability of the first mold 121.
[0056] The concave molding section 28 (first concave molding section 281) has a first end molding groove 38 closest to the side surface 321 having a fixing groove 30, and in the direction of movement of the upper mold 20, the first distance H1, which is the distance between the end 341a of the first side surface 341 that is furthest from the molding surface 22 (first molding surface 221) and the molding surface 22, and the second distance H2, which is the distance from the molding surface 22 to the deepest part 381 of the first end molding groove 38, satisfy the relationship H1 / H2 ≥ 0.53 (see Figure 9).
[0057] As a result, as shown in Figure 8A, even when the molded surface 22 is machined toward the fixing groove 30 by rethinking, the vertical thickness of the first side surface 341 is ensured to be at least 0.53 of the height of the deepest part 381 of the concave molded portion 28, thereby effectively suppressing the stress P generated in the side surface 321 having the fixing groove 30 when molding the molded product C. Therefore, cracking of the first mold 121 due to stress concentration is suppressed, and the durability of the first mold 121 can be improved.
[0058] As shown in Figure 4, the first fixing groove 301 has a bottom 40 that is furthest from the side surface 321 in the groove depth direction, and in the groove depth direction, the height E1 of the first side surface 341 relative to the bottom 40 is 1 / 2 or more of the height E2 of the second side surface 342 relative to the bottom 40. As a result, on the side surface 321 of the first mold 121, the first side surface 341 protrudes from the bottom 40 of the fixing groove 30 at a height of 1 / 2 or more of the second side surface 342, so that the area of the molding surface 22 connected to the first side surface 341 can be secured.
[0059] The first fixing groove 301 has a bottom 40 that is furthest from the side surface 321 in the groove depth direction, and in the groove depth direction, the height E1 of the first side surface 341 relative to the bottom 40 and the height E2 of the second side surface 342 relative to the bottom 40 are the same. This makes it easy to manufacture the first mold 121 by making the first side surface 341 and the second side surface 342 on the same plane.
[0060] In the direction of movement of the upper die 20, the first distance H1 and the second distance H2 satisfy the relationship H1 ≥ H2. As a result, by ensuring that the first distance H1 from the molding surface 22 to the end 341a of the first side portion 341 is larger than the second distance H2 from the molding surface 22 to the deepest part 381 of the first end molding groove 38, a large area of the molding surface 22 in the first die 121 can be secured even when the molding surface 22 is re-thinned, as shown in Figure 8A.
[0061] As shown in Figure 3, the first side portion 341 extends in the width direction, which is perpendicular to the groove depth direction of the fixing groove portion 30 and perpendicular to the movement direction of the upper mold 20. As a result, the rigidity of the first mold 121 can be effectively increased because the first side portion 341 extends in the width direction.
[0062] In the width direction of the first mold 121, the width W1 of the first side portion 341 is greater than or equal to the width W2 of the concave molded portion 28. By making the width W1 of the first side portion 341 greater than or equal to the width W2 of the concave molded portion 28 in the first mold 121, a wide area for increasing rigidity can be secured in the width direction, and the generation of stress P during molding can be effectively suppressed.
[0063] In addition to the disclosures mentioned above, the following further notes are made:
[0064] (Note 1) The forging die (10) comprises a lower die (18) and an upper die (20) that is movable vertically relative to the lower die. A first die (121), which is one of the lower die and the upper die, and a second die (122), which is the other of the lower die and the upper die, each have a forming surface (22). The forming surface of the first die and the forming surface of the second die face each other, and the first die and the second die are fixed to a holder (14) by fixing members (161, 162). At least the first mold includes a concave molding portion (28) recessed in the molding surface in accordance with the shape of the molded product (C), a holding surface (24) that abuts against the support surfaces (501, 502) of the holder intersecting the direction of movement of the upper mold, and side surfaces (321, 322) connecting the outer edge of the molding surface and the outer edge of the holding surface, wherein the side surfaces include a first side surface portion (341, 441) connected to the outer edge of the molding surface, a second side surface portion (342, 442) connected to the outer edge of the holding surface, and a fixing groove portion (30) provided between the first side surface portion and the second side surface portion, recessed horizontally relative to the first side surface portion and the second side surface portion, into which the fixing member is engaged.
[0065] With this configuration, in this forging die, the first side portion connected to the outer edge of the forming surface protrudes horizontally beyond the fixing groove portion. Therefore, compared to a configuration in which the fixing groove portion for engaging the fixing member extends to the forming surface, and a configuration in which the lower and upper dies are formed in a trapezoidal shape that tapers toward the forming surface, a larger area of the forming surface of the first die can be secured. As a result, the rigidity of at least the first die can be increased, and consequently, it becomes possible to form a wider concave forming portion on the forming surface.
[0066] (Note 2) In the forging die described in Appendix 1, the fixing groove portion has groove depths (D1, D2) in the horizontal direction, and the concave forming portion has end forming grooves (38, 48) closest to the side surface having the fixing groove portion, and the groove depth and the forming surface lengths L1, L2, which are the distances from the end forming grooves to the side surface, may satisfy the relationship D1, D2 / L1, L2 ≤ 0.229.
[0067] With this configuration, by ensuring the molding surface length of the first mold is such that the groove depth of the fixing groove is 0.229 or less of the molding surface length, the stress generated on the side surface with the fixing groove can be effectively suppressed when molding the molded product. As a result, cracking of the first mold due to stress concentration is suppressed, and the durability of the first mold can be improved.
[0068] (Note 3) In the forging die described in Appendix 1 or 2, the concave forming portion has an end forming groove closest to the side surface having the fixing groove, and in the direction of movement of the upper die, the first distance (H1), which is the distance between the end of the first side surface portion furthest from the forming surface (341a, 441a) and the forming surface, and the second distance (H2), which is the distance from the forming surface to the deepest part of the end forming groove (381, 481), may satisfy the relationship H1 / H2 ≥ 0.53.
[0069] With this configuration, even when the molded surface is machined toward the fixing groove by rethinking, the vertical thickness of the first side surface is ensured to be at least 0.53 times the height of the deepest part of the concave molded section. This effectively suppresses the stress generated on the side surface with the fixing groove when forming the molded product. As a result, cracking of the first mold due to stress concentration is suppressed, and the durability of the first mold can be improved.
[0070] (Note 4) In the forging die described in Appendix 1, the fixing groove has a bottom portion (40) that is furthest from the side surface in the groove depth direction, and in the groove depth direction, the height (E1) of the first side surface relative to the bottom portion may be 1 / 2 or more of the height (E2) of the second side surface relative to the bottom portion.
[0071] With this configuration, on the side surface, the first side surface protrudes from the bottom of the fixing groove at a height of more than half that of the second side surface, thus ensuring an area of the molded surface continuous with the first side surface.
[0072] (Note 5) In the forging die described in Appendix 1, the fixing groove portion has a bottom portion that is furthest from the side portion in the groove depth direction, and the height of the first side portion relative to the bottom portion and the height of the second side portion relative to the bottom portion may be the same in the groove depth direction.
[0073] With this configuration, the first side surface and the second side surface are on the same plane, making the first type easier to manufacture.
[0074] (Note 6) In the forging die described in Appendix 3, the first distance and the second distance may satisfy the relationship H1 ≥ H2 in the direction of movement of the upper die.
[0075] With this configuration, by ensuring that the first distance from the molding surface to the end of the first side surface is greater than the second distance from the molding surface to the deepest part of the end molding groove, a large area of the molding surface can be secured even when the molding surface is re-thinned.
[0076] (Note 7) In the forging die described in Appendix 1, the first side portion may extend in a width direction which is perpendicular to the groove depth direction of the fixing groove portion and perpendicular to the movement direction of the upper die.
[0077] With this configuration, the first side portion extends in the width direction, which effectively increases the rigidity of the first type.
[0078] (Note 8) In the forging die described in Appendix 7, the width of the first side portion (W1) in the width direction may be greater than or equal to the width of the concave forming portion (W2).
[0079] With this configuration, since the width of the first side surface is greater than the width of the concave molded portion, a wide area for increasing rigidity can be secured in the width direction, and stress generation during molding can be effectively suppressed.
[0080] Furthermore, the present invention is not limited to the disclosure described above, and can take various configurations without departing from the spirit of the invention. [Explanation of Symbols]
[0081] 10...Forging mold 121…Type 1 122…2nd type 14…Holder 161, 162... Fixing members 18…Lower mold 20…Upper mold 22…molding surface 24…Holding surface 28...Concave molded part 30…Fixing groove 321, 322... side view C…Molded product
Claims
1. A forging die comprising a lower die and an upper die that is movable vertically relative to the lower die, wherein each of the first die, which is one of the lower die and the upper die, and the second die, which is the other of the lower die and the upper die, has a molding surface, the molding surface of the first die and the molding surface of the second die face each other, and each of the first die and the second die is fixed to a holder by a fixing member, At least the first type, A recessed molded portion corresponding to the shape of the molded product is provided in relation to the molded surface, A holding surface that contacts the support surface of the holder, which intersects with the direction of movement of the upper mold, A side surface connecting the outer edge of the molded surface and the outer edge of the retaining surface, Equipped with, The aforementioned side surface comprises a first side surface portion connected to the outer edge portion of the molded surface, A second side surface portion connected to the outer edge of the retaining surface, It is provided between the first side portion and the second side portion, and is recessed horizontally relative to the first side portion and the second side portion, and includes a fixing groove portion into which the fixing member is engaged, The aforementioned fixing groove portion is An engaging end that extends along the horizontal direction and engages with the engaging portion of the fixing member in the vertical direction, The bottom portion is furthest from the side surface in the groove depth direction and intersects with the engagement end, Equipped with, The fixing force provided by the fixing member is applied to the engaging end in the vertical direction via the engaging portion, and the bottom portion and the engaging portion are spaced apart. The concave molded portion has an end molding groove closest to the side surface having the fixing groove, The fixing groove extends from the end of the side surface furthest from the molded surface to the bottom, and has a groove end surface that is spaced apart from the engaging end in the vertical direction, The groove depth is the distance between the side surface and the bottom in the horizontal direction, It has, The distance between the groove end face and the engaging end in the vertical direction is greater than the groove depth and the thickness of the engaging portion in the vertical direction. A forging die in which the groove end face is positioned closer to the engaging end than the deepest part of the end forming groove in the vertical direction.
2. In the forging die according to claim 1, A forging die in which the groove depth and the molding surface length L, which is the distance from the end molding groove to the side surface, satisfy the relationship D / L ≤ 0.
229.
3. In the forging die according to claim 1, A forging die in which, in the direction of movement of the upper die, the first distance H1, which is the distance between the end of the first side portion and the molding surface, and the second distance H2, which is the distance from the molding surface to the deepest part of the end molding groove, satisfy the relationship H1 / H2 ≥ 0.
53.
4. In the forging die according to claim 1, A forging die in which, in the groove depth direction, the height of the first side surface relative to the bottom is 1 / 2 or more of the height of the second side surface relative to the bottom.
5. In the forging die according to claim 1, The aforementioned fixing groove portion is A forging die in which, in the groove depth direction, the height of the first side surface relative to the bottom and the height of the second side surface relative to the bottom are the same.
6. In the forging die according to claim 3, A forging die in which, in the direction of movement of the upper die, the first distance H1 and the second distance H2 satisfy the relationship H1 ≥ H2.
7. In the forging die according to claim 1, The first side portion extends in the width direction, which is perpendicular to the groove depth direction of the fixing groove portion and perpendicular to the horizontal direction of movement of the upper die, forging die.
8. In the forging die according to claim 7, A forging die in which, in the width direction, the width of the first side surface is equal to or greater than the width of the concave forming portion.
Citation Information
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