Die structure of low-turbine shaft forge piece and forging demolding process

Abstract

The invention discloses a die structure of a low-vortex shaft forge piece and a forging demolding technology, and relates to the field of aviation shaft forge piece thermal deformation forming, the die structure of the low-vortex shaft forge piece comprises an upper die base, a lower die base, a flat pressing upper die, a forging upper die and a lower die, and the flat pressing upper die and the forging upper die are installed on the upper die base; the lower die is installed on the lower die base and used for being matched with the flat pressing upper die or the forging upper die to conduct the forging procedure, the lower die comprises a lower die outer ring and a lower die inner ring, the lower die outer ring is connected with the lower die base, the lower die inner ring is located on the inner side of the lower die outer ring and comprises a sizing part and a forging part, and the length of the forging part is larger than that of the sizing part. The sizing part and the forging part are coaxially arranged, the sizing part comprises two first semi-rings, and the forging part comprises two second semi-rings. The sizing part and the forging part of the inner ring of the lower die are separated from the forge piece in a radial parting mode, the forge piece does not need to be drawn, and local deformation and surface abrasion of the forge piece are reduced as much as possible.

Description

Technical Field

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

[0002] Low-pressure turbine shaft is short for low-pressure turbine shaft. 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 each stage of the aircraft engine's rotor system 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 step structure. Therefore, the use of a combined die forging process to produce a low-pressure turbine shaft is often the most economical and efficient way.

[0003] In the traditional low-pressure turbine shaft forging process, a robot is often used to assist in demolding by pulling or ejecting. This method has a simple demolding process and is easy to operate. However, this method also has many defects. It requires strict matching of equipment structure and mold design and sufficient lubrication. Otherwise, the forging and the mold are easily stuck and cannot be demolded. In addition, the low-pressure turbine shaft itself is a slender and hollow structure. Simply pulling or ejecting it to demold it is easy to cause local deformation of the forging and scratches on the outer surface of the forging, which is very unfavorable for the low-pressure turbine shaft with 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: A die structure for a low-vortex shaft forging, comprising an upper die seat, a lower die seat, 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 seat; the lower die is mounted on the lower die seat, 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 seat, wherein the lower die inner ring is located on the inner side of the lower die outer ring, wherein 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, wherein the sizing portion is coaxially arranged with the forging portion, and wherein the sizing portion comprises two first half rings.

[0006] 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 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 demoulded after the forging is completed, the low-pressure turbine shaft forging together with the inner ring of the lower die is pulled out from the outer ring of the lower die, and then the two first half rings are separated radially. When the forging is separated from the forging part later, the resistance between the forging and the forging part can be reduced, which is conducive to reducing the local deformation and surface wear during the demoulding process of the forging, and is conducive to ensuring the processing quality of the low-pressure turbine shaft.

[0007] Optionally, the forged portion comprises two second half rings.

[0008] 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 portion 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.

[0009] Optionally, a rod insertion hole is provided on the outer peripheral wall of the top end of the lower mold inner ring.

[0010] By adopting the above technical solution, 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 the lower die inner ring easier to separate from the lower die outer ring.

[0011] Optionally, a convex angle is provided at the lower end of the sizing portion, and a concave angle is provided at the upper end of the forging portion, and the convex angle is matched with the concave angle; and the dividing line between the two first half rings is aligned with the dividing line between the two second half rings.

[0012] By adopting the above technical solution, it is inevitable that protruding lines will be formed at the boundary line of the inner ring of the lower die after the forging is forged; under the premise of the cooperation of the convex angle and the concave angle, the sizing part is difficult to rotate relative to the forging part, so that the boundary line of the sizing part is consistent with the boundary line of the forging part, and the direction of the protruding lines on the surface of the forging after forming is consistent, so as to facilitate the surface grinding of the forging. On the other hand, the sizing part and the forging part can generate torque through the cooperation of the convex angle and the fillet, so that the sizing part can drive the forging part to rotate synchronously.

[0013] Optionally, the corner of the convex corner is an outer rounded corner, and the corner of the concave corner is an inner rounded corner.

[0014] 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.

[0015] 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.

[0016] By adopting the above technical solution, the first reinforcement ring can position the lower die inner ring, which is beneficial to ensure the relative position accuracy between the two half rings of the lower die inner ring. During the forging process, the force of the forging acting on the lower die inner ring indirectly acts on the first reinforcement ring, making it difficult for the lower die half rings to form a tendency to move away from each other, which is beneficial to maintaining the relative position accuracy between the two half rings.

[0017] 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, the pulling steel wire extends through the lower end surface and the outer peripheral surface of the lower die inner ring, 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.

[0018] 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 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 simultaneously applying force to the upper and lower ends of the lower die inner ring, it is helpful to make the lower die inner ring easier to remove from the lower die outer ring.

[0019] 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 axially with each other along 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 in the outer ring groove.

[0020] By adopting the above technical solution, the axial force of the clamp ring can be passed between the sizing part and the forging part, so that in the process of removing the lower die inner ring and the forging from the lower die outer ring, the forging part can be synchronously driven to leave the lower die outer ring by pulling the sizing part, so as to reduce the movement and friction of the forging relative to the forging part, which is beneficial to protecting the surface of the forging. When it is necessary to separate the two second half rings of the forging part, the clamp ring is rotated to a state where one end is aligned with the longitudinal interface of one of the second half rings, so that the other second half ring can be detached from the open ring at the notch of the clamp ring, and then the forging is taken out from the second half ring where the clamp ring is located. In the above process, the clamp ring only needs to produce a small deformation.

[0021] A low-turbo shaft forging demoulding process comprises the following steps: forging the shape of a forging by using a flat pressing upper die and a lower die; forging a blind hole of the forging by using a forging upper die and a lower die; moving the forging upper die upward to make room for demoulding; taking the forging out of the lower die outer ring together with the lower die inner ring; separating the two first half rings and the two second half rings constituting the lower die inner ring, taking out the forging, and completing demoulding.

[0022] 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.

[0023] Optionally, the following step is also included: when the lower mold inner ring is put back into the lower mold outer mold, the angle of the lower mold inner ring is rotated 90°.

[0024] Since the inner ring of the lower die is a radial parting structure, during the forging process, the outer ring of the lower die will be subjected to a large force along the parting direction of the inner ring of the lower die. By adopting the above technical solution, when the inner ring of the lower die is put back into the outer ring of the lower die, the rotation angle of the inner ring of the lower die is adjusted, so that the direction of the radial force mainly exerted on the outer ring of the lower die before and after can be staggered, thereby reducing the situation where the outer ring of the lower die is excessively deformed in a radial direction during operation.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 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.

[0026] 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 portion of the lower die inner ring is separated from the forging in a radial parting manner without drawing the forging to minimize local deformation and surface wear of the forging.

[0027] When the engagement 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

[0028] Figure 1 It is a schematic structural diagram of a low-pressure turbine shaft in the background technology.

[0029] Figure 2 It is a schematic diagram of the mold structure of Example 1 for reflecting the matching state of the flat pressing upper mold and the lower mold.

[0030] Figure 3It is a schematic diagram of the die structure of Example 1 for reflecting the matching state of the forging upper die and the lower die.

[0031] Figure 4 It is a schematic structural diagram of the lower die inner ring of Example 1.

[0032] Figure 5 yes Figure 3 Magnified view at A in the middle.

[0033] Figure 6 It is a schematic structural diagram of the lower mold of Example 2.

[0034] Figure 7 This is a schematic diagram of Example 2 for illustrating the relative position relationship between the pulling wire and the inner ring of the lower die.

[0035] Figure 8 It is a schematic structural diagram of the lower die inner ring of Example 2.

[0036] Description of reference numerals: 1. Upper die seat; 2. Lower die seat; 3. Flat press 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 angle; 522. Forging part; 5221. Second half ring; 5222. Inner groove; 5223. Inner ring groove; 5224. Concave angle; 523. Forming flange; 524. Rod insertion hole; 525. First annular groove; 526. Longitudinal avoidance groove; 527. Horizontal avoidance groove; 6. Positioning pin; 7. Snap ring; 71. Notch; 8. First reinforcement ring; 9. Lifting wire. DETAILED DESCRIPTION

[0037] The following is combined with Figure 2-8 This application is described in further detail. Example 1

[0038] The present application embodiment discloses a die structure for a low-vortex shaft forging. Figure 2 and Figure 3 The die structure of the low-turboshaft 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.

[0039] When forging the low-pressure turbine shaft, the flat pressing upper die 3 and the lower die 5 are first used to forge the outer shape of the low-pressure turbine shaft, and then the forging upper die 4 and the lower die 5 are used to forge the hollow inner cavity of the low-pressure turbine shaft.

[0040] In this embodiment, the flat pressing upper die 3 and the forging upper die 4 are respectively installed on different upper die holders 1. In other embodiments, the flat pressing upper die 3 and the forging upper die 4 can also be installed successively on the same upper die holder 1 in a replacement installation manner according to the processing sequence.

[0041] 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 is coaxially arranged with the forging portion 522. 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.

[0042] When 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.

[0043] Reference Figure 2 A molding flange 523 is provided at the top of the sizing portion 521, and the molding flange 523 is located on the outside of the inner cavity of the lower mold outer ring 51; an annular positioning protrusion 511 is protrudingly provided on the upper surface of the lower mold outer ring 51, and the outer diameter of the annular positioning protrusion 511 is consistent with the outer diameter of the molding 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 molding flange 523.

[0044] 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.

[0045] Reference Figure 3 The outer peripheral wall at the top 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 of the lower die inner ring 52 in the process of being disengaged from the lower die outer ring 51 is large, two rod-shaped tools can be respectively inserted into the rod insertion holes 524 to apply torque to the lower die inner ring 52, so that the lower die inner ring 52 is rotated and loosened, making it easier for the lower die inner ring 52 to be disengaged.

[0046] Reference Figure 4The lower end surface of the sizing portion 521 is provided with an annular boss 5212, 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, 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, a snap ring 7 is provided between the inner ring groove 5223 and the outer ring groove 5213, the snap ring 7 is snapped to the outer ring groove 5213, 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, and the arc angle of the snap ring 7 in this embodiment is set to 225°.

[0047] The axial force of the clamping ring 7 can pass between the sizing portion 521 and the forging portion 522, so that in the process of removing the lower die inner ring 52 and the forging from the lower die outer ring 51, the forging portion 522 can be synchronously driven to leave the lower die outer ring 51 by pulling the sizing portion 521. When it is necessary to separate the two second half rings 5221 of the forging portion 522, the clamping ring 7 is rotated to a state where one end is aligned with the longitudinal interface of one of the second half rings 5221, so that the other second half ring 5221 can be detached from the open ring at the notch 71 of the clamping ring 7, and then the forging is taken out from the second half ring 5221 where the clamping ring 7 is located.

[0048] Reference Figure 3 and Figure 5 , a first reinforcement ring 8 is provided at the bottom of the inner side of the lower die outer ring 51, and a first annular groove 525 for avoiding the first reinforcement ring 8 is provided on the bottom surface of the forging portion 522, the groove width of the first annular groove 525 is equal to the wire diameter of the first reinforcement ring 8, and the groove 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 can play a positioning role for the two second half rings 5221 of the forging portion 522, which is conducive to ensuring the relative position accuracy between the two second half rings 5221; and in the process of forging, the first reinforcement ring 8 can bear part of the reaction force from the forging, reducing the load of the forging acting on the lower die outer ring 51.

[0049] The present application also discloses a forging demoulding process for a low-vortex shaft forging, comprising the following steps: S1, forging the forging shape using a flat pressing upper die 3 and a lower die 5; S2, forging the blind hole of the forging part by using the forging upper die 4 and the lower die 5; in this process, the forging block 42 of the forging upper die 4 is connected with the sleeve 512 by using the positioning pin 6; S3, moving the forging upper die 4 and the sleeve 512 upward to make room for demoulding; S4, remove the forging together with the lower die inner ring 52 from the lower die outer ring 51; when 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 insertion hole 524 to apply torque to the lower die inner ring 52 to loosen the lower die inner ring 52; S5, 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 demolding is completed.

[0050] 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°.

[0051] 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, 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

[0052] 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.

[0053] Reference Figure 6 , Figure 7 and Figure 8 In this embodiment, a lifting 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 lifting wire 9 extends through the lower end surface and the outer peripheral surface of the lower die inner ring 52. Both ends of the lifting wire 9 extend out of the inner cavity of the lower die outer ring 51. The outer peripheral surface of the lower die inner ring 52 is provided with a longitudinal avoidance groove 526 extending in the axial direction. The longitudinal avoidance groove 526 is used to avoid the lifting 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 lifting wire 9. Both ends of the lifting wire 9 extend into the gap between the sleeve 512 and the annular positioning protrusion 511 respectively, and the inner wall of the sleeve 512 is provided with an inner avoidance groove for avoiding the lifting wire 9.

[0054] Reference Figure 6 A 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.

[0055] 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 simultaneously held 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 disengage from the lower die outer ring 51.

[0056] Reference Figure 6 , the structures of the upper end of the forging part 522 and the lower end of the sizing part 521 in this embodiment are different from those in Embodiment 1. In this embodiment, a convex corner 5214 is provided at the lower end of the sizing part 521, and the corner of the convex corner 5214 is an outer round corner. A concave corner 5224 is provided at the upper end of the forging part 522, and the corner of the concave corner 5224 is an inner round corner. 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 sizing part 521 and the forging part 522 can transmit torque through the convex corner 5214 and the concave corner 5224, so that the insert rod can indirectly drive the forging part 522 to rotate through the sizing part 521, so that the lower die inner ring 52 rotates as a whole relative to the lower die outer ring 51.

[0057] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A die structure for a low-turbo 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). 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) comprises a sizing portion (521) and a forging portion (522); the forging portion (522) is longer than the sizing portion (521); the sizing portion (521) is coaxially arranged with the forging portion (522); and the sizing portion (521) comprises two first half rings (5211).

2. The die structure of the low-vortex shaft forging according to claim 1 is characterized in that: The forged portion (522) includes two second half rings (5221).

3. The die structure of the low-vortex shaft forging according to claim 2 is 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).

4. The die structure of the low-vortex shaft forging according to claim 2 is characterized in that: The lower end of the sizing portion (521) is provided with a convex corner (5214), and the upper end of the forging portion (522) is provided with a concave corner (5224), and 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).

5. The die structure of the low-vortex shaft forging according to claim 4 is characterized in that: The corner of the convex corner (5214) is an outer rounded corner, and the corner of the concave corner (5224) is an inner rounded corner.

6. The die structure of a low-vortex shaft forging according to claim 2, characterized in that: A first reinforcement ring (8) is provided at the bottom of the inner side of the lower die outer ring (51), and a first annular groove (525) for avoiding the first reinforcement ring (8) is provided on the bottom surface of the lower die inner ring (52).

7. The die structure of the low-vortex shaft forging according to claim 2 is characterized in that: A pulling steel 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), and the pulling steel 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 steel wire (9) extend out of the inner cavity of the lower die outer ring (51). 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 steel 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 steel wire (9).

8. The die structure of the low-vortex shaft forging according to claim 2 is characterized in that: The lower end surface of the sizing portion (521) is provided with an annular boss (5212), 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), 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), a clamping ring (7) is provided between the inner ring groove (5223) and the outer ring groove (5213), the clamping ring (7) has a notch (71), the arc angle of the clamping ring (7) is less than 270 degrees and greater than 180 degrees, and the clamping ring (7) is clamped to the outer ring groove (5213).

9. A demoulding process for low-vortex shaft forging, based on the die structure of the low-vortex shaft forging according to any one of claims 2 to 8, characterized in that: The steps include: Forging the forging shape by using a flat pressing upper die (3) and a lower die (5); Forging a blind hole of a forging part by using an upper forging die (4) and a lower forging die (5); Move the upper forging 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 respectively, and the forging is taken out to complete demoulding.

10. The low-vortex shaft forging demoulding process according to claim 9, characterized in that: The step further includes: when the lower die inner ring (52) is put back into the lower die outer die (5), the angle of the lower die inner ring (52) is rotated by 90°.

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