A die structure and forging demoulding process for a low-vortex shaft forging

Abstract

The present application discloses a die structure and forging demolding process for a low-vortex shaft forging, relating to the field of hot deformation forming of aviation shaft forgings. The die structure of the low-vortex shaft forging includes an upper die base, a lower die base, a flat-pressing upper die, a forging upper die, and a lower die. The flat-pressing upper die and the forging upper die are respectively mounted on the upper die base; the lower die is mounted on the lower die base and is used to cooperate with the flat-pressing upper die or the forging upper die to perform a forging process. The lower die includes a lower die outer ring and a lower die inner ring. The lower die outer ring is connected to the lower die base, and the lower die inner ring is located inside the lower die outer ring. The lower die inner ring includes a sizing portion and a forging portion. The forging portion is longer than the sizing portion and is coaxially arranged with the forging portion. The sizing portion includes two first half rings, and the forging portion includes two second half rings. In the present application, the sizing portion and the forging portion of the lower die inner ring are separated from the forging by radial parting, eliminating the need for drawing the forging, thereby minimizing local deformation and surface wear of the forging.

Description

Technical Field

[0001] The present application relates to the field of thermal deformation forming of aviation shaft forgings, and in particular to a die structure and forging demolding process of a low-vortex shaft forging. Background Art

[0002] Low-pressure turbine shaft is short for low-pressure turbine shaft. The low-pressure turbine shaft is a key transmission component throughout the multi-stage rotor system of the aircraft engine. Its function is to transfer the kinetic energy generated by the turbine rotor to the various rotor systems of the aircraft engine under the premise of carrying the turbine rotor, thereby generating thrust. Therefore, the low-pressure turbine shaft needs to bear huge loads during operation, so there are extremely strict technical requirements for the manufacture of low-pressure turbine shafts. In order to ensure that the low-pressure turbine shaft can meet sufficient strength and toughness requirements, it is generally processed by forging. A common type of low-pressure turbine shaft has a trumpet-shaped structure at one end, is hollow and straight throughout, and has a multi-step structure. Therefore, the use of a combined die forging process to produce low-pressure turbine shafts is often the most economical and efficient way.

[0003] In the traditional low-pressure turbine shaft forging process, demolding is often performed with the assistance of a robot, using a pulling or ejecting method. This method is simple and easy to operate. However, this method also has many drawbacks. It requires a strict match between the equipment structure and mold design and sufficient lubrication. Otherwise, the forging and the mold are prone to getting stuck, making demolding impossible. In addition, the low-pressure turbine shaft itself is a slender and hollow structure. Simply pulling or ejecting it can easily lead to local deformation of the forging and scratches on the outer surface of the forging. This is very disadvantageous for the low-pressure turbine shaft, which has extremely high production technology requirements. Summary of the Invention

[0004] In order to reduce local deformation and external surface damage of a low-pressure turbine shaft processed by forging during the demolding process, the present application provides a die structure and a forging demolding process for a low-pressure turbine shaft forging.

[0005] The die structure and forging demoulding process of a low-vortex shaft forging provided in this application adopt the following technical solutions:

[0006] A die structure for a low-vortex shaft forging comprises an upper die base, a lower die base, a flat pressing upper die, a forging upper die and a lower die, wherein the flat pressing upper die and the forging upper die are respectively mounted on the upper die base; the lower die is mounted on the lower die base, and the lower die is used to cooperate with the flat pressing upper die or the forging upper die to perform a forging process, wherein the lower die comprises a lower die outer ring and a lower die inner ring, wherein the lower die outer ring is connected to the lower die base, and the lower die inner ring is located on the inner side of the lower die outer ring, and the lower die inner ring comprises a sizing portion and a forging portion, wherein the length of the forging portion is greater than that of the sizing portion, the sizing portion is coaxially arranged with the forging portion, and the sizing portion comprises two first half rings.

[0007] By adopting the above technical solution, when processing the low-pressure turbine shaft, the basic shape of the low-pressure turbine shaft is first forged by using the flat pressing upper die and the lower die, and then the hollow inner cavity of the low-pressure turbine shaft is processed by using the forging upper die and the lower die. During the forging process of the low-pressure turbine shaft, the inner ring of the lower die mainly shapes the outer diameter of the low-pressure turbine shaft through the sizing part, so the fit between the sizing part and the forging is tighter. When the low-pressure turbine shaft is forged and demolded, the low-pressure turbine shaft forging together with the lower die inner ring is pulled out from the lower die outer ring, and then the two first half rings are separated radially. When the forging is subsequently separated from the forging part, the resistance between the forging and the forging part can be reduced, which is conducive to reducing local deformation and surface wear during the demolding process of the forging, and is conducive to ensuring the processing quality of the low-pressure turbine shaft.

[0008] Optionally, the forged portion includes two second half rings.

[0009] By adopting the above technical solution, when the low-pressure turbine shaft forging together with the lower die inner ring is pulled out from the lower die outer ring, the forged part of the lower die inner ring is separated from the forging in a radial parting manner, and there is no need to draw the forging, so as to minimize local deformation and surface wear of the forging.

[0010] Optionally, a rod insertion hole is provided on the outer peripheral wall of the top end of the lower mold inner ring.

[0011] By adopting the above technical solution, when the joining force between the lower mold inner ring and the lower mold outer ring needs to be larger, a rod-shaped tool can be inserted into the rod hole to rotate the lower mold inner ring to loosen the lower mold inner ring, thereby making the lower mold inner ring easier to separate from the lower mold outer ring.

[0012] Optionally, a convex corner is provided at the lower end of the sizing portion, and a concave corner is provided at the upper end of the forging portion, and the convex corner is adapted to the concave corner; and the dividing line between the two first half rings is aligned with the dividing line between the two second half rings.

[0013] By adopting the above technical solution, after forging, protruding lines inevitably form at the boundary line of the lower die inner ring. Under the premise of the convex and concave corners, the calibrating section is difficult to rotate relative to the forging section, so that the boundary line of the calibrating section and the boundary line of the forging section are consistent, and the direction of the protruding lines on the surface of the forging after forming is consistent, which facilitates surface grinding of the forging. Furthermore, the calibrating section and the forging section cooperate through the convex and rounded corners to generate torque between the calibrating section and the forging section, allowing the calibrating section to drive the forging section to rotate synchronously.

[0014] Optionally, the corner of the convex corner is an outer rounded corner, and the corner of the concave corner is an inner rounded corner.

[0015] By adopting the above technical solution, the convex corners are set as outer round corners and the concave corners are set as inner round corners, which is beneficial to reducing the stress concentration at the matching position of the sizing part and the forging part.

[0016] Optionally, a first reinforcement ring is provided at the bottom of the inner side of the lower mold outer ring, and a first annular groove for avoiding the first reinforcement ring is provided on the bottom surface of the lower mold inner ring.

[0017] By adopting this technical solution, the first reinforcement ring can position the lower die inner ring, helping to ensure the relative position accuracy between the two halves of the lower die inner ring. During the forging process, the force exerted by the forging on the lower die inner ring indirectly acts on the first reinforcement ring, preventing the lower die halves from moving away from each other, which helps maintain the relative position accuracy between the two halves.

[0018] Optionally, a pulling steel wire is provided between the outer surface of the lower die inner ring and the inner surface of the lower die outer ring, and the pulling steel wire extends through the lower end face and outer peripheral surface of the lower die inner ring, and both ends of the pulling steel wire extend out of the inner cavity of the lower die outer ring. The outer peripheral surface of the lower die inner ring is provided with a longitudinal avoidance groove extending along the axial direction, and the longitudinal avoidance groove is used to avoid the pulling steel wire; the bottom surface of the lower die inner ring or the inner bottom surface of the lower die outer ring is provided with a transverse avoidance groove for avoiding the pulling steel wire.

[0019] By adopting the above technical solution, in the process of removing the forging and the lower die inner ring from the lower die outer ring, in addition to pulling the top end of the lower die inner ring, it is also possible to simultaneously hold both ends of the pulling wire to apply an upward pulling force to the lower die inner ring and the forging. By applying force to the upper and lower ends of the lower die inner ring at the same time, it is helpful to make the lower die inner ring easier to remove from the lower die outer ring.

[0020] Optionally, the lower end face of the sizing portion is provided with an annular boss, the upper end face of the forging portion is provided with an inner groove adapted to the annular boss, the inner circumferential surface of the inner groove is provided with an inner ring groove, the outer circumferential surface of the annular boss is provided with an outer ring groove, the inner ring groove and the outer ring groove are aligned along the axial direction of the inner ring of the lower die, a retaining ring is provided between the inner ring groove and the outer ring groove, the retaining ring has a notch, the arc angle of the retaining ring is less than 270 degrees and greater than 180 degrees, and the retaining ring is clamped to the outer ring groove.

[0021] By adopting the above technical solution, the axial force of the clamping ring can be passed between the sizing part and the forging part. Therefore, when the lower die inner ring and the forging are removed from the lower die outer ring, the sizing part can be pulled to synchronously drive the forging part away from the lower die outer ring, thereby reducing the movement and friction of the forging part relative to the forging part, which is beneficial to protecting the surface of the forging part. When it is necessary to separate the two second half rings of the forging part, the clamping ring is rotated until one end is aligned with the longitudinal interface of one of the second half rings. In this way, the other second half ring can be released from the notch of the clamping ring and the forging part can be removed from the second half ring where the clamping ring is located. During the above process, the clamping ring only needs to undergo minor deformation.

[0022] A low-vortex shaft forging demolding process comprises the following steps: forging the outer shape of a forging using a flat pressing upper die and a lower die; forging a blind hole of the forging using the forging upper die and the lower die; moving the forging upper die upward to make room for demolding; removing the forging together with the lower die inner ring from the lower die outer ring; separating the two first half rings and the two second half rings constituting the lower die inner ring, removing the forging, and completing demolding.

[0023] By adopting the above technical solution, the forging does not need to be drawn during the process of being taken out from the inner ring of the lower die, which is beneficial to reducing local deformation and surface damage of the forging.

[0024] Optionally, the method further includes the following step: when the lower die inner ring is put back into the lower die outer die, the angle of the lower die inner ring is rotated 90°.

[0025] Since the lower die inner ring is a radial parting structure, the lower die outer ring will be subjected to a large force along the parting direction of the lower die inner ring during the forging process; by adopting the above technical solution, when the lower die inner ring is put back into the lower die outer ring, the rotation angle of the lower die inner ring is adjusted, so that the directions of the radial forces mainly exerted on the front and rear of the lower die outer ring can be staggered, thereby reducing the situation where the lower die outer ring is excessively deformed in a radial direction during operation.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] When the low-pressure turbine shaft is demolded after processing, the low-pressure turbine shaft forging together with the lower die inner ring is pulled out from the lower die outer ring, and then the two first half rings are separated radially. When the forging is subsequently separated from the forging part, the resistance between the forging and the forging part can be reduced, which is beneficial to reducing local deformation and surface wear during the demolding process of the forging, and is beneficial to ensuring the processing quality of the low-pressure turbine shaft.

[0028] When the low-pressure turbine shaft forging is pulled out from the lower die outer ring together with the lower die inner ring, the forged part of the lower die inner ring is separated from the forging in a radial parting manner, without the need to draw the forging, so as to minimize local deformation and surface wear of the forging.

[0029] When the joining force between the lower die inner ring and the lower die outer ring needs to be larger, a rod-shaped tool can be inserted into the rod hole to rotate the lower die inner ring to loosen the lower die inner ring, thereby making it easier to separate the lower die inner ring from the lower die outer ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a low-pressure turbine shaft in the background technology.

[0031] Figure 2 It is a schematic diagram of the mold structure of Example 1, which is used to reflect the matching state of the flat pressing upper mold and the lower mold.

[0032] Figure 3 It is a schematic diagram of the die structure used to reflect the matching state of the forging upper die and the lower die in Example 1.

[0033] Figure 4 It is a structural schematic diagram of the lower mold inner ring of Example 1.

[0034] Figure 5 yes Figure 3 Magnified view of point A in the middle.

[0035] Figure 6 It is a structural schematic diagram of the lower mold of Example 2.

[0036] Figure 7 This is a schematic diagram of Example 2 used to illustrate the relative positional relationship between the pulling wire and the inner ring of the lower die.

[0037] Figure 8 It is a structural schematic diagram of the lower mold inner ring of Example 2.

[0038] Description of reference numerals:

[0039] 1. Upper die base; 2. Lower die base; 3. Flat pressing upper die; 4. Forging upper die; 41. Blind hole rod; 42. Forging block; 5. Lower die; 51. Lower die outer ring; 511. Annular positioning protrusion; 512. Sleeve; 52. Lower die inner ring; 521. Sizing part; 5211. First half ring; 5212. Annular boss; 5213. Outer ring groove; 5214. Protruding corner; 522. Forging part; 5221. Second half ring; 5222. Inner groove; 5223. Inner ring groove; 5224. Concave corner; 523. Forming flange; 524. Rod insertion hole; 525. First annular groove; 526. Longitudinal avoidance groove; 527. Horizontal avoidance groove; 6. Locating pin; 7. Snap ring; 71. Notch; 8. First reinforcement ring; 9. Lifting wire. DETAILED DESCRIPTION

[0040] The following is combined with Figure 2-8 This application is described in further detail. Example 1

[0041] The embodiment of the present application discloses a die structure for a low-vortex shaft forging. Figure 2 and Figure 3 The mold structure of the low-vortex shaft forging includes an upper die base 1, a lower die base 2, a flat pressing upper die 3, a forging upper die 4 and a lower die 5. The upper die base 1 is provided with two, and the flat pressing upper die 3 and the forging upper die 4 are respectively installed on the two upper die bases 1; the lower die 5 is installed on the lower die base 2, and the lower die 5 is used to cooperate with the flat pressing upper die 3 or the forging upper die 4 to carry out the forging process.

[0042] When forging the low-pressure turbine shaft, the flat pressing upper die 3 and the lower die 5 are first used to cooperate with each other to forge the low-pressure turbine shaft's outer shape, and then the forging upper die 4 and the lower die 5 are used to cooperate with each other to process the low-pressure turbine shaft's hollow inner cavity.

[0043] In this embodiment, the flat pressing die 3 and the forging die 4 are respectively installed on different die holders 1. In another embodiment, the flat pressing die 3 and the forging die 4 can also be installed on the same die holder 1 in a replacement installation manner according to the processing sequence.

[0044] Reference Figure 3 and Figure 4 The lower die 5 includes a lower die outer ring 51 and a lower die inner ring 52. The lower die outer ring 51 is fixedly connected to the lower die base 2. The lower die inner ring 52 is located on the inner side of the lower die outer ring 51. The lower die inner ring 52 includes a sizing portion 521 and a forging portion 522. The sizing portion 521 and the forging portion 522 are coaxially arranged. The length of the forging portion 522 is greater than that of the sizing portion 521. The sizing portion 521 includes two first half rings 5211, and the forging portion 522 includes two second half rings 5221.

[0045] After the low-pressure turbine shaft is processed, the forging is taken out together with the lower die inner ring 52 , and then the two first half rings 5211 and the two second half rings 5221 are separated radially to achieve demoulding.

[0046] Reference Figure 2 The top of the sizing part 521 is provided with a forming flange 523, and the forming flange 523 is located on the outside of the inner cavity of the lower mold outer ring 51; the upper surface of the lower mold outer ring 51 is protrudingly provided with an annular positioning protrusion 511, and the outer diameter of the annular positioning protrusion 511 is consistent with the outer diameter of the forming flange 523. The annular positioning protrusion 511 is sleeved with a sleeve 512, and the sleeve 512 is used to form the trumpet-shaped structure of the low-pressure turbine shaft together with the flat pressing upper mold 3 and the forming flange 523.

[0047] Reference Figure 3 The forging upper die 4 includes a blind hole rod 41 and a forging block 42. The blind hole rod 41 is used to form the blind hole of the low-pressure turbine shaft. The forging block 42 is sleeved on the blind hole rod 41. A positioning pin 6 is inserted between the forging block 42 and the sleeve 512. The forging block 42 is used to press the trumpet-shaped structure of the low-pressure turbine shaft. When the blind hole rod 41 is in the process of forming the inner hole of the low-pressure turbine shaft, the trumpet-shaped structure of the low-pressure turbine shaft can remain fixed.

[0048] Reference Figure 3 The outer peripheral wall of the top end of the lower die inner ring 52 is provided with two rod insertion holes 524, which are symmetrically arranged along the center line of the lower die inner ring 52. When the resistance to the lower die inner ring 52 coming out of the lower die outer ring 51 is large, two rod-shaped tools can be inserted into the rod insertion holes 524 to apply torque to the lower die inner ring 52, causing it to rotate and loosen, making it easier to come out.

[0049] Reference Figure 4 The lower end surface of the sizing portion 521 is provided with an annular boss 5212, and the upper end surface of the forging portion 522 is provided with an inner groove 5222 adapted to the annular boss 5212, the inner circumferential surface of the inner groove 5222 is provided with an inner ring groove 5223, and the outer circumferential surface of the annular boss 5212 is provided with an outer ring groove 5213. The inner ring groove 5223 and the outer ring groove 5213 are aligned along the axial direction of the lower die inner ring 52, and a snap ring 7 is provided between the inner ring groove 5223 and the outer ring groove 5213. The snap ring 7 is clamped in the outer ring groove 5213, and the snap ring 7 has a notch 71. The arc angle of the snap ring 7 is less than 270 degrees and greater than 180 degrees. In this embodiment, the arc angle of the snap ring 7 is set to 225°.

[0050] The axial force of the clamping ring 7 can be applied between the sizing portion 521 and the forging portion 522. As a result, during the process of removing the lower die inner ring 52 and the forged part from the lower die outer ring 51, the sizing portion 521 can be pulled to simultaneously drive the forging part 522 away from the lower die outer ring 51. To separate the two second half rings 5221 of the forging part 522, the clamping ring 7 is rotated until one end is aligned with the longitudinal interface of one of the second half rings 5221. This allows the other second half ring 5221 to be released from the notch 71 of the clamping ring 7. The forged part can then be removed from the second half ring 5221 where the clamping ring 7 is located.

[0051] Reference Figure 3 and Figure 5 A first reinforcement ring 8 is provided at the bottom inner side of the lower die outer ring 51, and a first annular groove 525 is provided on the bottom surface of the forged portion 522 to accommodate the first reinforcement ring 8. The width of the first annular groove 525 is equal to the wire diameter of the first reinforcement ring 8, and the depth of the first annular groove 525 is greater than or equal to the wire diameter of the first reinforcement ring 8. The first reinforcement ring 8 positions the two second half rings 5221 of the forged portion 522, thereby ensuring the relative position accuracy between the two second half rings 5221. Furthermore, during the forging process, the first reinforcement ring 8 can bear part of the reaction force from the forging, reducing the load exerted by the forging on the lower die outer ring 51.

[0052] The present application also discloses a forging demoulding process for a low-vortex shaft forging, comprising the following steps:

[0053] S1, forging the forging shape using the flat pressing upper die 3 and the lower die 5;

[0054] S2, forging the blind hole of the forging part using the forging upper die 4 and the lower die 5; during this process, the forging block 42 of the forging upper die 4 and the sleeve 512 are connected using the positioning pin 6;

[0055] S3, move the forging upper die 4 and the sleeve 512 upward to make room for demoulding;

[0056] S4, remove the forging together with the lower die inner ring 52 from the lower die outer ring 51; if the resistance between the lower die inner ring 52 and the lower die outer ring 51 is large, a rod-shaped tool can be inserted into the rod hole 524 to apply torque to the lower die inner ring 52 to loosen the lower die inner ring 52;

[0057] S5, separating the two first half rings 5211 and the two second half rings 5221 constituting the lower die inner ring 52, taking out the forging, and completing demolding.

[0058] S6, when the lower die inner ring 52 is put back into the lower die 5 outer die, the angle of the lower die inner ring 52 is rotated 90 degrees.

[0059] The implementation principle of the mold structure and forging demolding process of a low-pressure turbine shaft forging in an embodiment of the present application is as follows: when the low-pressure turbine shaft is demolded after processing is completed, the low-pressure turbine shaft forging together with the lower die inner ring 52 is pulled out from the lower die outer ring 51, and then the two first half rings 5211 and the two second half rings 5221 are separated radially respectively, without the need to draw and demold the forging, which is beneficial to reducing local deformation and surface wear during the demolding process of the forging, thereby helping to ensure the processing quality of the low-pressure turbine shaft. Example 2

[0060] The die structure of the low-vortex shaft forging in this embodiment is different from that in Embodiment 1, and the first reinforcement ring 8 is not provided in this embodiment.

[0061] Reference Figure 6 、 Figure 7 and Figure 8 In this embodiment, a pulling wire 9 is provided between the outer surface of the lower die inner ring 52 and the inner surface of the lower die outer ring 51. The pulling wire 9 extends through the lower end surface and outer circumference of the lower die inner ring 52. Both ends of the pulling wire 9 extend out of the inner cavity of the lower die outer ring 51. The outer circumference of the lower die inner ring 52 is provided with a longitudinal avoidance groove 526 extending axially. The longitudinal avoidance groove 526 is used to avoid the pulling wire 9. The bottom surface of the lower die inner ring 52 or the inner bottom surface of the lower die outer ring 51 is provided with a transverse avoidance groove 527 for avoiding the pulling wire 9. The two ends of the pulling wire 9 respectively extend into the gap between the sleeve 512 and the annular positioning protrusion 511. The inner wall of the sleeve 512 is provided with an inner avoidance groove for avoiding the pulling wire 9.

[0062] Reference Figure 6A longitudinal chamfer is provided between the outer circumference of the first half ring 5211 and the longitudinal interface, and the area between the longitudinal chamfers of the two first half rings 5211 serves as a longitudinal avoidance groove 526; a longitudinal chamfer is provided between the outer circumference of the second half ring 5221 and the longitudinal interface, and the area between the longitudinal chamfers of the two second half rings 5221 serves as a longitudinal avoidance groove 526; a transverse chamfer is provided between the bottom surface of the second half ring 5221 and the longitudinal interface, and the area between the longitudinal chamfers of the two second half rings 5221 serves as a transverse avoidance groove 527.

[0063] In the process of removing the forging and the lower die inner ring 52 from the lower die outer ring 51, in addition to pulling the top of the lower die inner ring 52, the two ends of the pulling wire 9 can be held at the same time to apply an upward pulling force to the lower die inner ring 52 and the forging. By applying force to the upper and lower ends of the lower die inner ring 52 at the same time, it is helpful to make the lower die inner ring 52 easier to remove from the lower die outer ring 51.

[0064] Reference Figure 6 In this embodiment, the structures of the upper end of the forging portion 522 and the lower end of the sizing portion 521 differ from those in Example 1. In this embodiment, the lower end of the sizing portion 521 is provided with a convex corner 5214 with an outer rounded corner, while the upper end of the forging portion 522 is provided with a concave corner 5224 with an inner rounded corner. The convex corner 5214 and the concave corner 5224 are adapted to fit together; the boundary line between the two first half-rings 5211 and the boundary line between the two second half-rings 5221 are aligned. Torque can be transmitted between the sizing portion 521 and the forging portion 522 via the convex corner 5214 and the concave corner 5224, allowing the insert rod to indirectly drive the forging portion 522 to rotate through the sizing portion 521, thereby causing the lower die inner ring 52 to rotate as a whole relative to the lower die outer ring 51.

[0065] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A die structure for a low-turbine shaft forging, characterized in that: The invention comprises an upper die base (1), a lower die base (2), a flat pressing upper die (3), a forging upper die (4) and a lower die (5), wherein the flat pressing upper die (3) and the forging upper die (4) are respectively mounted on the upper die base (1); the lower die (5) is mounted on the lower die base (2), and the lower die (5) is used to cooperate with the flat pressing upper die (3) or the forging upper die (4) to perform a forging process, and the lower die (5) comprises a lower die outer ring (51) and a lower die inner ring (52), and the lower die outer ring (51) is connected to the lower die base (2). ), the lower die inner ring (52) is located on the inner side of the lower die outer ring (51), the lower die inner ring (52) includes a sizing portion (521) and a forging portion (522), the length of the forging portion (522) is greater than the sizing portion (521), the sizing portion (521) and the forging portion (522) are coaxially arranged, the sizing portion (521) includes two first half rings (5211); the forging portion (522) includes two second half rings (5221); the lower sizing portion (521) The end of the forging portion (522) is provided with a convex corner (5214), the upper end of the forging portion (522) is provided with a concave corner (5224), the convex corner (5214) is adapted to the concave corner (5224); the dividing line of the two first half rings (5211) is aligned with the dividing line of the two second half rings (5221); the corner of the convex corner (5214) is an outer fillet, and the corner of the concave corner (5224) is an inner fillet; a pulling wire ( 9), the pulling wire (9) extends through the lower end surface and the outer peripheral surface of the lower die inner ring (52), and both ends of the pulling wire (9) extend out of the inner cavity of the lower die outer ring (51), and the outer peripheral surface of the lower die inner ring (52) is provided with a longitudinal avoidance groove (526) extending in the axial direction, and the longitudinal avoidance groove (526) is used to avoid the pulling wire (9); the bottom surface of the lower die inner ring (52) or the inner bottom surface of the lower die outer ring (51) is provided with a transverse avoidance groove (527) for avoiding the pulling wire (9).

2. The die structure of the low-vortex shaft forging according to claim 1, characterized in that: A rod insertion hole (524) is provided on the outer peripheral wall of the top end of the lower die inner ring (52).

3. A low-vortex shaft forging demolding process, based on the die structure of the low-vortex shaft forging according to any one of claims 1-2, characterized in that: The steps include: Forging the forging shape using a flat pressing upper die (3) and a lower die (5); Forging the blind hole of the forging piece using the forging upper die (4) and the lower die (5); Move the forging upper die (4) upward to make room for demoulding; Remove the forging together with the lower die inner ring (52) from the lower die outer ring (51); The two first half rings (5211) and the two second half rings (5221) constituting the lower die inner ring (52) are separated, the forging is taken out, and demoulding is completed.

4. The low-vortex shaft forging demolding process according to claim 3, characterized in that: The following steps are also included: when the lower die inner ring (52) is put back into the lower die (5) outer die, the angle of the lower die inner ring (52) is rotated 90 degrees.

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