Hard alloy forging and pressing forming equipment

Abstract

The invention discloses hard alloy forging forming equipment, which belongs to the technical field of forging forming and comprises a forging press, a forging head is fixedly connected onto the forging press, a table-shaped forging die corresponding to the forging head is arranged on the forging press, and the table-shaped forging die comprises a forging outer die, a forging inner die, a middle wedge block and an extension die shell. According to the device, the edge profiling forging and pressing block moves upwards to conduct forging and pressing shaping on the edge area of the first-layer table-shaped part of the preformed part, and the base plate part and the second-layer table-shaped part of the preformed part are pressed and deformed in the forging and pressing outer mold and the forging and pressing inner mold correspondingly; the first forging and pressing frame and the second forging and pressing frame can extrude the two extension mold shells from the outer side, force is directly applied to the deformation part of the preformed part through the extension mold shells, the movable deformation part of the preformed part is forged and pressed, and the deformation part of the table-shaped connecting area of the preformed part is subjected to area division constraint and independent forging and pressing.

Description

Technical Field

[0001] The invention relates to the technical field of forging and forming, and in particular to a hard alloy forging and forming device. Background Art

[0002] Forging is the process of heating the powder sintered preform and forging it into a part in a closed die. Boss forgings have multiple stepped boss parts, which can be divided into different parts from different boss parts. It is also easy to pick up, so it is a common shape of forged parts. When tungsten-cobalt alloy is forged into boss forgings, the sintered table-shaped preform is aligned and inverted into the forging die on the working surface of the forging machine. The forging head impacts the preform from above, and the preform is deformed inside the forging die to fill the forming space inside the forging die. The boss connection part of the preform stretches and deforms into the forming space of the part with reduced diameter. Due to the obstruction of the corresponding part of the forging die, different areas of the connection part deform to different degrees and directions. The forging head always maintains a state of vertically impacting the preform from above, allowing the preform to deform freely inside the forging die. It is impossible to perform regional constraints on the boss connection parts at different levels of the table-shaped preform during the deformation process, and it is also impossible to perform a separate secondary forging on this part, which makes the table-shaped connection part of the preform after forging prone to deformation and defects, affecting the forging forming effect of the tungsten-cobalt alloy boss forging. Summary of the invention

[0003] The object of the present invention is to provide a cemented carbide forging and forming equipment to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A cemented carbide forging and forming equipment, comprising a forging machine, a forging head being fixedly connected to the forging machine, a table-shaped forging die corresponding to the forging head being provided on the forging machine, the table-shaped forging die comprising an outer forging die, an inner forging die, a middle wedge block and an extension die shell, the number of the extension die shells being two, the inner forging die, the middle wedge block and the two extension die shells being positioned directly below the forging head through the outer forging die; two single-layer forging modules and two double-layer edge forging modules are provided inside the outer forging die, the single-layer forging module comprising a first forging frame and a first pushing frame, the first forging frame being positioned above the extension die shell and the forging die through the first pushing frame Between the outer dies, the two-layer edge forging module includes an edge profiling forging block, a second forging frame and a second pushing frame. The edge profiling forging block and the second forging frame are positioned between the forging inner die and the forging outer die through the second pushing frame. The first forging frame, the edge profiling forging block and the second forging frame forge the active deformation part of the preform. A lifting drive module is provided under the table-shaped forging die. The lifting drive module includes a driving frame and a driving member. The driving member controls the driving frame to push the edge profiling forging block to move. The outer side wall of the forging outer die is fixedly connected to two symmetrically distributed guide boxes, and a plurality of adjustment tubes are slidably connected inside the guide box.

[0006] Furthermore, the inner forging die is fixedly connected to the center position inside the outer forging die, and the middle wedge block is fixedly connected to the inner side wall of the outer forging die.

[0007] Furthermore, the two extension mold shells are distributed one above and one below, the bottom of the extension mold shell in the upper position is fixedly connected to the inner wall of the forging outer mold, and the bottom of the extension mold shell in the lower position is fixedly connected to the top of the forging inner mold, and the middle wedge block is located between the two extension mold shells.

[0008] Furthermore, the first pushing frame is fixedly connected to the outer side wall of the first forging frame, and the first pushing frame is slidably connected to the inside of the forging outer die.

[0009] Furthermore, the edge profiling forging block is slidably connected between the forging outer die and the forging inner die, the second forging frame is located between the edge profiling forging block and the extension die shell in the lower position, the second pushing frame is fixedly connected to the outer side wall of the second forging frame, and the second pushing frame is slidably connected to the inside of the forging outer die.

[0010] Furthermore, the driving member is fixedly connected to the forging machine, the driving frame is fixedly connected to the output end of the driving member, and the top of the driving frame is fixedly connected to the bottom of the edge contour forging block.

[0011] Furthermore, a guide groove corresponding to the adjusting tube is opened inside the guide box, and the adjusting tube is slidably connected inside the corresponding guide groove. Several adjusting tubes are distributed inside and outside, and the bottom end of the adjusting tube on the inner side corresponds to the first pushing frame, and the bottom end of the adjusting tube on the outer side corresponds to the second pushing frame.

[0012] Furthermore, two compression shells corresponding to the guide boxes are provided on the outside of the forging head, a fixing frame is fixedly connected to the top of the compression shell, and the other end of the fixing frame is fixedly connected to the outer wall of the forging head.

[0013] Furthermore, a clearance groove corresponding to the second forging frame is provided on the forging inner die, and the bottom end of the second forging frame is plugged into the clearance groove.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention provides a table-shaped forging die, and cooperates with a forging head to forge and form a table-shaped tungsten-cobalt alloy part after sintering. The preformed part is deformed between the forging outer die and the forging inner die under the impact of the forging head. The edge profiling forging block moves upward to forge and shape the edge area of ​​the first-layer table-shaped part of the preformed part. The chassis part and the second-layer table-shaped part of the preformed part are respectively compressed and deformed inside the forging outer die and the forging inner die. The two groups of regulating tubes located on the side of the table-shaped forging die push the first push frame and the second push frame toward the inner side of the forging outer die under the downward pressure of the two pressure shells that follow the forging head downward. By changing the positions of the first forging frame and the second forging frame on the inner side of the table-shaped forging die, the first forging frame and the second forging frame squeeze the two extension mold shells from the outside, and directly apply force to the deformed part of the preform through the extension mold shell, the effect of forging the active deformed part of the preform is achieved, and the deformed part of the table-shaped connection area of ​​the preform can be divided and constrained and forged separately, thereby reducing the deformation and defects that are prone to occur in the table-shaped connection part of the preform after forging, which is conducive to efficiently forging and forming the table-shaped tungsten-cobalt alloy parts after sintering, and improving the forging forming accuracy and efficiency of the tungsten-cobalt alloy parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0017] Figure 2 It is a front view structural schematic diagram of the present invention;

[0018] Figure 3 It is a schematic diagram of the cross-sectional structure of the present invention;

[0019] Figure 4 It is a schematic cross-sectional structure diagram of the present invention in use.

[0020] In the figure, 1, forging machine; 11, forging head; 12, pressure shell; 121, fixed frame; 2, table-shaped forging die; 21, forging outer die; 22, forging inner die; 221, make way groove; 23, middle wedge block; 24, extension mold shell; 3, first layer forging module; 31, first forging frame; 32, first push frame; 4, second layer edge forging module; 41, edge contour forging block; 42, second forging frame; 43, second push frame; 5, lifting drive module; 51, drive frame; 52, drive member; 6, guide box; 61, adjustment tube; 62, guide groove. DETAILED DESCRIPTION

[0021] The principles and features of the present invention are described below in conjunction with examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0022] See also Figure 1-Figure 4 In an embodiment of the present invention, a cemented carbide forging forming device includes a forging machine 1, a forging head 11 is fixedly connected to the forging machine 1, a table-shaped forging die 2 corresponding to the forging head 11 is provided on the forging machine 1, the table-shaped forging die 2 includes a forging outer die 21, a forging inner die 22, a middle wedge block 23 and an extension die shell 24, the number of the extension die shells 24 is two, the forging inner die 22, the middle wedge block 23 and the two extension die shells 24 are all positioned directly below the forging head 11 through the forging outer die 21, two single-layer forging modules 3 and two double-layer edge forging modules 4 are provided inside the forging outer die 21, the single-layer forging module 3 includes a first forging frame 31 and a first pushing frame 32, the first forging frame 31 is positioned above the extension die shell 2 through the first pushing frame 32 4 and the forging outer die 21, the two-layer edge forging module 4 includes an edge profiling forging block 41, a second forging frame 42 and a second pushing frame 43, the edge profiling forging block 41 and the second forging frame 42 are positioned between the forging inner die 22 and the forging outer die 21 through the second pushing frame 43, the first forging frame 31, the edge profiling forging block 41 and the second forging frame 42 forge the active deformation part of the preform, a lifting drive module 5 is provided below the table-shaped forging die 2, the lifting drive module 5 includes a driving frame 51 and a driving member 52, the driving member 52 controls the driving frame 51 to push the edge profiling forging block 41 to move, the outer side wall of the forging outer die 21 is fixedly connected to two symmetrically distributed guide boxes 6, and a plurality of adjusting tubes 61 are slidably connected inside the guide box 6.

[0023] The forging machine 1 is provided with a table-shaped forging die 2 and a forging head 11. The forging head 11 is connected to the driving part of the forging machine 1. The table-shaped forging die 2 corresponds to the position directly below the forging head 11. The sintered preform is aligned and placed in the table-shaped forging die 2. The forging machine 1 is operated to control the forging head 11 to move down close to the table-shaped forging die 2 to perform the forging and forming operation of the preform. The table-shaped forging die 2 is composed of an outer forging die 21, an inner forging die 22, a middle wedge block 23 and an extended die shell 24. The inner forging die 22 is fixedly connected to the center position of the outer forging die 21, and the middle wedge block 23 is fixedly connected to the inner side wall of the outer forging die 21. There are two extension mold shells 24, which are arranged one above and one below. The bottom of the extension mold shell 24 at the upper position is fixedly connected to the inner wall of the forging outer die 21, and the bottom of the extension mold shell 24 at the lower position is fixedly connected to the top of the forging inner die 22. The two extension mold shells 24 are connected to the forging outer die 21 and the forging inner die 22 one above and one below. The two extension mold shells 24 sandwich the middle wedge block 23 in the middle, so that the middle wedge block 23 can extrude and guide the preform in the designated area inside the forging outer die 21. The forging outer die 21 can be positioned and connected to the designated area on the forging machine 1 through the column at the bottom, and the table-shaped forging die 2 is positioned as a whole just below the forging head 11. A forging forming space adapted to the table-shaped tungsten-cobalt alloy preform is formed between the forging outer die 21, the forging inner die 22, the middle wedge block 23 and the two extension mold shells 24. The preform is aligned and placed inside the forging forming space for forging.

[0024] Two first-layer forging modules 3 and two second-layer edge forging modules 4 are arranged inside the forging outer die 21. The first-layer forging module 3 is located above the second-layer edge forging module 4. The first-layer forging module 3 and the second-layer edge forging module 4 respectively fill the vacant space inside the forging outer die 21. The first-layer forging module 3 is composed of a first forging frame 31 and a first push frame 32. The first push frame 32 is fixedly connected to the outer wall of the first forging frame 31. The forging outer die 21 is provided with a matching groove corresponding to the first push frame 32. The first push frame 32 is slidably connected inside the corresponding matching groove on the forging outer die 21, so that the first forging frame 31 is positioned between the extension mold shell 24 in the upper position and the forging outer die 21 through the first push frame 32. The first pushing frame 32 can move horizontally inside the corresponding matching groove on the forging outer die 21, so that the first forging frame 31 can move horizontally between the extension mold shell 24 in the upper position and the forging outer die 21, which is beneficial to change the position of the first forging frame 31 inside the table-shaped forging die 2.

[0025] The second-layer edge forging module 4 is composed of an edge profiling forging block 41, a second forging frame 42 and a second push frame 43. The edge profiling forging block 41 is slidably connected between the forging outer die 21 and the forging inner die 22. The second forging frame 42 is located between the edge profiling forging block 41 and the extension die shell 24 at the lower position. The second push frame 43 is fixedly connected to the outer wall of the second forging frame 42 to position the second-layer edge forging module 4 inside the table-shaped forging die 2. A matching groove corresponding to the second push frame 43 is also provided on the forging outer die 21. The second push frame 43 is slidably connected inside the corresponding matching groove on the forging outer die 21. The height of the matching groove corresponding to the second push frame 43 is greater than the height of the second push frame 43, so that the second push frame 43 can move horizontally and vertically in the corresponding matching groove, which is conducive to changing the position of the edge profiling forging block 41 and the second forging frame 42 inside the table-shaped forging die 2. A lifting drive module 5 is arranged below the table-shaped forging die 2. The lifting drive module 5 is composed of a driving frame 51 and a driving member 52. The driving member 52 is fixedly connected to the forging machine 1. The driving frame 51 is fixedly connected to the output end of the driving frame 52. The top of the driving frame 51 is fixedly connected to the bottom of the edge profiling forging block 41. The driving member 52 operates by controlling the driving frame 51 to move on the forging machine 1 to push the edge profiling forging block 41 to move vertically between the forging outer die 21 and the forging inner die 22, so that the edge profiling forging block 41 moves closer to the middle wedge block 23. The forging inner die 22 is provided with a clearance groove 221 corresponding to the second forging frame 42. The bottom end of the second forging frame 42 is plugged into the clearance groove 221. The clearance groove 221 provides clearance space for the second forging frame 42 when it moves downward, ensuring that the edge profiling forging block 41 can smoothly change its position in the vertical direction inside the table-shaped forging die 2.

[0026] The outer wall of the forging outer die 21 is fixedly connected with two symmetrically distributed guide boxes 6, and the inside of the guide box 6 is connected with a plurality of adjustment tubes 61 in a sliding manner. The inside of the guide box 6 is provided with a guide groove 62 corresponding to the adjustment tube 61, and the adjustment tube 61 is slidably connected inside the corresponding guide groove 62. The top end of the adjustment tube 61 extends from the top of the guide box 6. The top end of the adjustment tube 61 is subjected to force, which enables the adjustment tube 61 to move inside the corresponding guide groove 62, thereby changing the position of the adjustment tube 61 inside the guide box 6. The plurality of adjustment tubes 61 are distributed inside and outside, and the bottom end of the adjustment tube 61 on the inside corresponds to the first push frame 32, and the bottom end of the adjustment tube 61 on the outside corresponds to the second push frame 43. By changing the position of the adjustment tube 61 inside the guide box 6, the plurality of adjustment tubes 61 are respectively close to the first push frame 32 or the second push frame 43. The first push frame 32 and the second push frame 43 are pushed by the corresponding adjustment tubes 61 and can move toward the inside of the forging outer die 21, so that the first forging frame 31 and the edge contour forging block 41 can change their positions inside the forging outer die 21. Two compression shells 12 corresponding to the guide boxes 6 are arranged on the outside of the forging head 11, and the top of the compression shell 12 is fixedly connected with a fixing frame 121, and the other end of the fixing frame 121 is fixedly connected with the outer wall of the forging head 11, so that the two compression shells 12 are fastened to the outside of the forging head 11. The compression shell 12 moves downward with the forging head 11, and applies pressure to the adjustment tubes 61 in the two guide boxes 6 from above. The position of the compression shell 12 is higher than the bottom end of the forging head 11, so that the forging head 11 contacts the preform in the table-shaped forging die 2 before the compression shell 12, so that the preform can first undergo active deformation in the table-shaped forging die 2. After the preform is deformed in the table-shaped forging die 2, the first layer forging module 3 and the second layer edge forging module 4 perform independent adjustment operations by moving the position of the adjustment tube 61.

[0027] The table-shaped forging die 2 cooperates with the forging head 11 to forge the table-shaped tungsten-cobalt alloy parts after sintering. The preform is aligned and placed in the table-shaped forging die 2. The forging head 11 moves down and approaches the table-shaped forging die 2 from above. The forging head 11 enters the forging outer die 21 to impact the chassis part of the preform. The preform is deformed between the forging outer die 21 and the forging inner die 22 under the impact of the forging head 11. The first and second table-shaped parts of the preform are deformed between the forging outer die 21, the forging inner die 22 and the middle wedge block 23, and the preform is elongated to fill the forging forming space in the table-shaped forging die 2. Driven by the driving member 52, the driving frame 51 pushes the edge profiling forging blocks 41 of the two molds to move vertically upward inside the table-shaped forging die 2, so that the edge profiling forging blocks 41 can be aligned and connected with the middle wedge block 23 from the bottom, fill the empty space between the extension mold shell 24 and the forging inner mold 22 at the bottom, and support the extension mold shell 24 from the outside. In the process of the forging head 11 impacting the preform to deform the preform, the top of the edge profiling forging block 41 corresponds to the profiling part of the edge area of ​​the table-shaped part of the preform, and the edge area of ​​the first-layer table-shaped part of the preform can be forged and shaped. The chassis part and the second-layer table-shaped part of the preform are respectively compressed and deformed inside the forging outer mold 21 and the forging inner mold 22, and the preform is forged and formed in the table-shaped forging die 2. After the forging head 11 impacts the preform, the two pressure shells 12 apply force from above to press down the adjustment tubes 61 in the two guide boxes 6. The two groups of adjustment tubes 61 located on the side of the table-shaped forging die 2 move inside the guide groove 62 and push the first push frame 32 and the second push frame 43 to the inside of the forging outer die 21 under the downward pressure of the two pressure shells 12 following the forging head 11, changing the position of the first forging frame 31 and the second forging frame 42 on the inside of the table-shaped forging die 2. The first forging frame 31 and the second forging frame 42 are both semicircular structures, and the two extension mold shells 24 correspond to the deformed part of the preform. The first forging frame 31 and the second forging frame 42 change their positions to squeeze the two extension mold shells 24 from the outside, and apply force to the deformed part of the preform through the extension mold shell 24, so as to achieve the effect of forging the movable deformed part of the preform. The cooperation between the table-shaped forging die 2, the first layer forging module 3 and the second layer edge forging module 4 can divide and constrain the deformation part of the table-shaped connection area of ​​the preform and perform separate forging, thereby reducing the deformation and defects that are prone to occur in the table-shaped connection part of the preform after forging, which is beneficial to the efficient forging and forming of the table-shaped tungsten-cobalt alloy parts after sintering, and improving the forging and forming accuracy and efficiency of the tungsten-cobalt alloy parts.

[0028] The working principle of the present invention is as follows: the sintered table-shaped tungsten-cobalt alloy preform is aligned and inverted in the table-shaped forging die 2, the forging machine 1 controls the forging head 11 to move downward and approach the table-shaped forging die 2 from above, the forging head 11 enters the forging outer die 21 to impact the chassis part of the preform, the preform is deformed between the forging outer die 21 and the forging inner die 22 under the impact of the forging head 11, the first table-shaped part and the second table-shaped part of the preform are deformed between the forging outer die 21, the forging inner die 22 and the middle wedge block 23, the preform is elongated to fill the forging forming space in the table-shaped forging die 2, the driving member 52 operates to allow the driving frame 51 to push the edge profiling forging blocks 41 of the two molds to move vertically upward, so that the edge profiling forging blocks 41 are aligned and connected with the middle wedge block 23 from below, filling the extended mold shell 2 at the lower position. 4 and the empty space between the forging inner die 22, and at the same time, the profiling part on the top of the edge profiling forging block 41 forges and shapes the edge area of ​​the first layer of the table-shaped part of the preform, and the chassis part and the second layer of the table-shaped part of the preform are respectively compressed and deformed inside the forging outer die 21 and the forging inner die 22. After the forging head 11 impacts the preform, the two pressure shells 12 apply force from above to press down the adjusting tubes 61 in the two guide boxes 6, and the two groups of adjusting tubes 61 move inside the corresponding guide grooves 62 and push the first pushing frame 32 and the second pushing frame 43 toward the inside of the forging outer die 21. The first forging frame 31 and the second forging frame 42 change their positions and apply force to the deformed part of the preform from the outside through the extension die shell 24, forging the active deformed part of the preform, and after the preform is completely forged and formed inside the table-shaped forging die 2, it is taken out from the inside of the table-shaped forging die 2 upward.

[0029] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A cemented carbide forging and forming device, comprising a forging machine (1), wherein a forging head (11) is fixedly connected to the forging machine (1), characterized in that: The forging machine (1) is provided with a table-shaped forging die (2) corresponding to the forging head (11), the table-shaped forging die (2) comprising a forging outer die (21), a forging inner die (22), a middle wedge block (23) and an extension die shell (24), the number of the extension die shells (24) is two, the forging inner die (22), the middle wedge block (23) and the two extension die shells (24) are all positioned directly below the forging head (11) through the forging outer die (21); The forging outer die (21) is provided with two single-layer forging modules (3) and two double-layer edge forging modules (4). The single-layer forging module (3) comprises a first forging frame (31) and a first pushing frame (32). The first forging frame (31) is positioned between the upper extension die shell (24) and the forging outer die (21) through the first pushing frame (32). The double-layer edge forging module (4) comprises an edge profiling forging block (41), a second forging frame (42) and a second pushing frame (43). The edge profiling forging block (41) and the second forging frame (42) are positioned between the forging inner die (22) and the forging outer die (21) through the second pushing frame (43). The first forging frame (31), the edge profiling forging block (41) and the second forging frame (42) forge the active deformation part of the preform. A lifting drive module (5) is provided below the table-shaped forging die (2), the lifting drive module (5) comprising a driving frame (51) and a driving member (52), the driving member (52) controlling the driving frame (51) to push the edge contour forging block (41) to move, the outer side wall of the forging outer die (21) being fixedly connected to two symmetrically distributed guide boxes (6), the guide box (6) being slidably connected to a plurality of adjustment tubes (61); The inner forging die (22) is fixedly connected to the inner center of the outer forging die (21), and the middle wedge block (23) is fixedly connected to the inner side wall of the outer forging die (21).

2. The cemented carbide forging and forming equipment according to claim 1, characterized in that: The two extension mold shells (24) are arranged one above and one below. The bottom of the extension mold shell (24) at the upper position is fixedly connected to the inner wall of the forging outer mold (21), and the bottom of the extension mold shell (24) at the lower position is fixedly connected to the top of the forging inner mold (22). The middle wedge block (23) is located between the two extension mold shells (24).

3. The cemented carbide forging and forming equipment according to claim 1, characterized in that: The first pushing frame (32) is fixedly connected to the outer side wall of the first forging frame (31), and the first pushing frame (32) is slidably connected to the inside of the forging outer die (21).

4. The cemented carbide forging and forming equipment according to claim 1, characterized in that: The edge profiling forging block (41) is slidably connected between the forging outer die (21) and the forging inner die (22); the second forging frame (42) is located between the edge profiling forging block (41) and the extension die shell (24) at a lower position; the second pushing frame (43) is fixedly connected to the outer side wall of the second forging frame (42); and the second pushing frame (43) is slidably connected to the inside of the forging outer die (21).

5. The cemented carbide forging and forming equipment according to claim 1, characterized in that: The driving member (52) is fixedly connected to the forging machine (1), the driving frame (51) is fixedly connected to the output end of the driving member (52), and the top end of the driving frame (51) is fixedly connected to the bottom end of the edge profiling forging block (41).

6. The cemented carbide forging and forming equipment according to claim 1, characterized in that: A guide groove (62) corresponding to the adjusting tube (61) is provided inside the guide box (6), and the adjusting tube (61) is slidably connected inside the corresponding guiding groove (62). A plurality of adjusting tubes (61) are distributed inside and outside, and the bottom end of the adjusting tube (61) on the inside corresponds to the first pushing frame (32), and the bottom end of the adjusting tube (61) on the outside corresponds to the second pushing frame (43).

7. The cemented carbide forging and forming equipment according to claim 1, characterized in that: Two compression shells (12) corresponding to the guide boxes (6) are arranged on the outside of the forging head (11); a fixing frame (121) is fixedly connected to the top of the compression shell (12); and the other end of the fixing frame (121) is fixedly connected to the outer wall of the forging head (11).

8. The cemented carbide forging and forming equipment according to claim 1, characterized in that: The inner forging die (22) is provided with a clearance groove (221) corresponding to the second forging frame (42), and the bottom end of the second forging frame (42) is plugged into the clearance groove (221).

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