CN111842751A

CN111842751A - Forging method for new energy automobile hub

Info

Publication number: CN111842751A
Application number: CN202010714222.5A
Authority: CN
Inventors: 苏强; 黄其扬
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2020-10-30

Abstract

The invention relates to the technical field of automobile manufacturing, in particular to a forging method of a new energy automobile hub, wherein a forging device used in the method comprises a lifting mechanism, an outer expanding mechanism and an inner expanding mechanism, the outer expanding mechanism and the inner expanding mechanism are installed in the lifting mechanism, the inner expanding mechanism is sleeved in the outer expanding mechanism, the lifting mechanism comprises a forging box, a taking and placing groove, a bottom box, a first threaded rod, a second threaded rod, a belt pulley, a transmission belt, a driving gear, a driven gear and a first motor, the taking and placing groove is formed in the middle of the upper side of the forging box, the bottom box is fixedly connected to the bottom wall of the forging box, the first threaded rod and the second threaded rod are rotatably embedded in the bottom box, and a lifting plate ascends to push the heights of a sliding hinge seat and a second hinge seat so as to reduce an included angle between the first inclined rod and the second inclined rod, so that the two outer mould shells are close to each other and the two outer mould shells are close to each other.

Description

Forging method for new energy automobile hub

Technical Field

The invention relates to the technical field of automobile manufacturing, in particular to a forging method of a new energy automobile hub.

Background

The new energy automobile hub is a part for mounting an axle in the center of a wheel, namely a conventional 'rim' or 'steel ring', the hub is easily stained with dirt, and if the new energy automobile hub is not cleaned for a long time, the hub is possibly corroded and deformed to cause potential safety hazards.

In the automobile wheel hub manufacturing technology, often adopt the integral type structure, steel ring and spoke are integrative promptly, also have steel ring and spoke to adopt the components of a whole that can function independently structure, but the spoke of difference freely arranges the steel ring, and the form change is more various, and during the forging of wheel hub steel ring, generally need four sets of forging and pressing equipment, except last mould and lower mould, mould forging and pressing wheel groove about in addition need, the step is comparatively loaded down with trivial details, and the substep forging and pressing makes the unable integrated into one piece of steel ring, has great influence to the wheel hub performance.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a forging method of a new energy automobile hub.

The technical scheme adopted by the invention for solving the technical problems is as follows: a forging method for a new energy automobile hub comprises the following steps:

s1, cleaning the surface of the cut alloy blank by using a tap water high-pressure spray gun, polishing the surface by using a machine, putting the alloy blank into a carburizing furnace for carburizing, cooling the alloy blank to room temperature by using an oil cooling method after the carburizing is finished, and then quenching the alloy blank;

s2, placing the quenched alloy blank into a taking and placing groove in a forging device, placing an annular hot die on the upper side of an extension plate, starting a first motor to drive a driving gear to rotate, further engaging a transmission driven gear, driving a first threaded rod, enabling the first threaded rod to rotate and driving a second threaded rod to rotate through a transmission belt, and effectively lifting a lifting plate under the screw driving action of the first threaded rod, the second threaded rod and the internal thread 28 so as to integrally form a wheel hub steel ring;

the forging device in the S2 comprises a lifting mechanism, an external expanding mechanism and an internal expanding mechanism, wherein the lifting mechanism is internally provided with the external expanding mechanism and the internal expanding mechanism, and the internal expanding mechanism is sleeved in the external expanding mechanism.

Specifically, the lifting mechanism comprises a forging box, a taking and placing groove, a bottom box, a first threaded rod, a second threaded rod, a belt pulley, a transmission belt, a driving gear, a driven gear and a first motor, the middle part of the upper side of the forging box is provided with a taking and placing groove, the bottom wall of the forging box is fixedly connected with a bottom box, a first threaded rod and a second threaded rod are embedded on the bottom box in a rotating way, the bottom ends of the first threaded rod and the second threaded rod are both connected with the bottom wall of the forging box in a rotating way through bearings, the outer walls of the bottom ends of the first threaded rod and the second threaded rod are fixedly sleeved with belt pulleys, a transmission belt is connected between the two belt pulleys in a transmission way, fixed cover on the outer wall of a threaded rod is equipped with driven gear, one side of a threaded rod and the upside screw fixation that is located the under casing have a motor, the output shaft of a motor passes under casing fixedly connected with drive gear.

Specifically, the external expanding mechanism comprises a first hinged support, a first inclined rod, a second hinged support, a third hinged support, an external formwork, an extension plate, a lifting plate, an internal thread, a second inclined rod, a jack and an inserted rod, the lifting plate is positioned in the forging box, two internal threads are symmetrically arranged on the lifting plate, a first hinged support is fixedly connected on the upper part of the lifting plate and the inner wall of the lifting plate opposite to the inner wall of the forging box, the upper sides of the two ends of the lifting plate are fixedly connected with a second hinged support, two outer formworks are arranged in the taking and placing groove and on the upper opposite side of the lifting plate, one sides of the two outer formworks far away from each other are fixedly connected with a third hinged support, no. three hinged brackets and No. two hinged brackets are hinged with No. two down tubes, No. one hinged brackets and No. three hinged brackets are hinged with No. one down tube, two jacks are formed in the adjacent sides of the outer formwork, and two insertion rods are fixedly connected to the adjacent sides of the outer formwork.

Specifically, the internal expanding mechanism comprises a central shaft column, a main gear, a connecting cylinder, a limiting ring, a second motor, an auxiliary gear, a rotating shaft, a fourth hinged support, a third inclined rod, an internal mold shell, a sliding chute, a sliding hinged support, a fourth inclined rod and a fifth hinged support, wherein the central shaft column is embedded at the upper side of the middle part of the bottom box, the main gear is fixedly sleeved on the outer wall of the bottom end of the central shaft column, the connecting cylinder is fixedly connected to the upper side of the main gear and positioned at the outer side of the central shaft column, the limiting ring is fixedly sleeved on the outer wall of the top end of the connecting cylinder and is rotatably connected with the bottom box through a bearing, the second motor is fixed on the upper side of the bottom box and positioned at one side of the central shaft column through a screw, the output shaft of the second motor penetrates through the auxiliary gear fixedly connected with the bottom box, the top end of the central shaft column penetrates through the lifting plate, the top end of, two spouts have been seted up to the middle part outer wall of center pedestal, all inlay in the spout and be equipped with the slip free bearing, the both sides of center pedestal all are equipped with interior mould shell, the equal fixedly connected with free bearing of five of the equal sides of interior mould shell, all articulate between free bearing of five and the free bearing of four there is No. three down tube, all articulate between slip free bearing and the free bearing of five there is No. four down tube.

Specifically, the external screw thread has all been seted up to the top outer wall of a threaded rod and No. two threaded rods, drive gear is connected with driven gear meshing.

Specifically, two threaded rods and No. two threaded rods are respectively embedded in the internal threads, the lifting plate is connected with the inner wall of the forging box in a sliding mode, the lifting plate is connected with the central shaft column in a sliding mode, the outer formworks jointly enclose a circular cavity, the positions of the jacks correspond to the positions of the insertion rods, the lengths of the third inclined rod, the fourth inclined rod, the first inclined rod and the second inclined rod are identical, and an extrusion die cavity is arranged between the inner formwork and the outer formwork.

The invention has the beneficial effects that:

(1) according to the forging method of the new energy automobile hub, the lifting plate rises to push the sliding hinged support and the second hinged support to be high, so that the included angle between the first inclined rod and the second inclined rod is reduced, the two outer mold shells are close to each other, and in the process that the two outer mold shells are close to each other, the included angle between the third inclined rod and the second inclined rod can be synchronously reduced, so that the two inner mold shells are far away from each other, and the extrusion annular hot mold is deformed.

(2) According to the forging method of the new energy automobile hub, the central shaft column rotates automatically, the third diagonal rod and the fourth diagonal rod can be driven to rotate, the two inner formworks are driven to rotate and extrude along the inner wall of the annular hot mold, so that the annular formed hub can be formed, and the high-strength hub can be formed after the hot-pressing model is cooled.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a flow chart of a method of the present invention;

FIG. 2 is a sectional view showing the structure of a forging apparatus according to the present invention;

FIG. 3 is a schematic structural view of an internal expanding mechanism of the forging apparatus according to the present invention;

FIG. 4 is a schematic structural view of an outer mold shell in the forging apparatus of the present invention;

FIG. 5 is an enlarged view of the structure at A in FIG. 2 according to the present invention;

FIG. 6 is an enlarged view of the structure at B in FIG. 2 according to the present invention.

In the figure: 1. a lifting mechanism; 11. forging a box; 12. a taking and placing groove; 13. a bottom box; 14. a first threaded rod; 15. a second threaded rod; 16. a belt pulley; 17. a drive belt; 18. a drive gear; 19. a driven gear; 110. a first motor; 2. an outward expansion mechanism; 21. a first hinge base; 22. a first inclined rod; 23. a second hinged support; 24. a third hinged support; 25. an outer formwork; 26. an extension plate; 27. a lifting plate; 28. an internal thread; 29. a second diagonal rod; 210. a jack; 211. inserting a rod; 3. an internal expanding mechanism; 31. a central axial column; 32. a main gear; 33. a connecting cylinder; 34. a limiting ring; 35. a second motor; 36. a pinion gear; 37. a rotating shaft; 38. a fourth hinged support; 39. a third diagonal rod; 310. an inner formwork; 311. a chute; 312. sliding hinged supports; 313. a fourth diagonal rod; 314. and a fifth hinged support.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

As shown in fig. 1 to 6, the forging method for the new energy automobile hub, provided by the invention, comprises the following steps:

s2, placing the quenched alloy blank into a taking and placing groove 12 in a forging device, placing an annular hot die on the upper side of an extension plate 26, starting a first motor 110, driving a driving gear 18 to rotate, further engaging a transmission driven gear 19, driving a first threaded rod 14, enabling the first threaded rod 14 to rotate and driving a second threaded rod 15 to rotate through a transmission belt 17, and effectively lifting a lifting plate 27 under the screw driving action of the first threaded rod 14, the second threaded rod 15 and an internal screw 28 so as to integrally form a wheel hub steel ring;

forging device in S2 includes elevating system 1, expands mechanism 2 outward and expands mechanism 3 in with, install in elevating system 1 and expand mechanism 2 outward and expand mechanism 3 in with, expand mechanism 2 endotheca outward and be equipped with expand mechanism 3 in, drive by elevating system 1 and expand mechanism 2 outward and expand mechanism 3 deformation in with, expand mechanism 2 and expand mechanism 3 mutually supporting by outward and add oil heating ring mould, integrated into one piece wheel hub steel ring with expanding mechanism 3 in.

Specifically, elevating system 1 is including forging case 11, getting and putting groove 12, under casing 13, a threaded rod 14, No. two threaded rods 15, belt pulley 16, driving belt 17, drive gear 18, driven gear 19 and a motor 110, the upside middle part of forging case 11 has been seted up and has been got and put groove 12, fixedly connected with under casing 13 on forging case 11's the diapire, it inlays and is equipped with a threaded rod 14 and No. two threaded rods 15 to rotate on under casing 13, the bottom of a threaded rod 14 and No. two threaded rods 15 all is connected with forging case 11 diapire rotation through the bearing, the equal fixed cover in bottom outer wall of a threaded rod 14 and No. two threaded rods 15 is equipped with belt pulley 16, two the transmission is connected with driving belt 17 between the belt pulley 16, fixed cover is equipped with driven gear 19 on the outer wall of a threaded rod 14, one side of a threaded rod 14 and the upside screw fixation that is located under casing 13 have a motor 110, an output shaft of a motor 110 passes bottom case 13 fixedly connected with drive gear 18, starts a motor 110, drives drive gear 18 and rotates, and then meshes transmission driven gear 19, drives threaded rod 14 No. one, and threaded rod 14 rotation just drives threaded rod 15 No. two through driving belt 17 and rotates, under threaded drive effect of threaded rod 14 and threaded rod 15 No. two and internal thread 28, can effectively lift lifter plate 27.

Specifically, the external expanding mechanism 2 comprises a first hinged support 21, a first inclined rod 22, a second hinged support 23, a third hinged support 24, an external mold shell 25, an extension plate 26, a lifting plate 27, internal threads 28, a second inclined rod 29, a jack 210 and an insert rod 211, wherein the lifting plate 27 is positioned in the forging box 11, the lifting plate 27 is symmetrically provided with two internal threads 28, the first hinged support 21 is fixedly connected above the lifting plate 27 and on the opposite inner wall of the forging box 11, the upper sides of the two ends of the lifting plate 27 are fixedly connected with the second hinged support 23, the upper opposite side of the lifting plate 27 is positioned in the taking and placing groove 12 and is provided with two external mold shells 25, one sides of the two external mold shells 25, which are far away from each other, are fixedly connected with the third hinged support 24, the second inclined rod 29 is hinged between the third hinged support 24 and the second hinged support 23, the first inclined rod 22 is hinged between the first hinged support 21 and the third hinged support 24, two jack 210 has all been seted up to the adjacent side of outer mould shell 25, two the equal fixedly connected with inserted bar 211 of the adjacent side of outer mould shell 25, in outer expanding mechanism 2, lifter plate 27 rises, can promote No. two free bearings 23 and rise, and then changes the contained angle between an down tube 22 and No. two down tubes 29 for two outer mould shells 25 are close to each other, and inserted bar 211 corresponds the grafting with jack 210, thereby avoids outer mould shell 25 concatenation dislocation.

Specifically, the internal expanding mechanism 3 includes a central shaft column 31, a main gear 32, a connecting cylinder 33, a limiting ring 34, a second motor 35, a pinion 36, a rotating shaft 37, a fourth hinged support 38, a third diagonal rod 39, an inner mold shell 310, a sliding chute 311, a sliding hinged support 312, a fourth diagonal rod 313 and a fifth hinged support 314, the central shaft column 31 is embedded in the upper side of the middle of the bottom box 13, the main gear 32 is fixedly sleeved on the outer wall of the bottom end of the central shaft column 31, the upper side of the main gear 32 is fixedly connected with the connecting cylinder 33 outside the central shaft column 31, the limiting ring 34 is fixedly sleeved on the outer wall of the top end of the connecting cylinder 33, the limiting ring 34 is rotatably connected with the bottom box 13 through a bearing, the second motor 35 is fixed on the upper side of the bottom box 13 and on one side of the central shaft column 31 through a screw, the output shaft of the second motor 35 penetrates through the bottom box 13 and is fixedly connected with the pinion 36, the top end of the central shaft column 31 penetrates through the, the outer wall of the top end of the central shaft column 31 is fixedly connected with two fourth hinged supports 38, the outer wall of the middle of the central shaft column 31 is provided with two sliding grooves 311, sliding hinged supports 312 are embedded in the sliding grooves 311, inner formworks 310 are arranged on two sides of the central shaft column 31, five hinged supports 314 are fixedly connected to adjacent sides of the inner formworks 310, three inclined rods 39 are hinged between the five hinged supports 314 and the four hinged supports 38, four inclined rods 313 are hinged between the sliding hinged supports 312 and the five hinged supports 314, and in the inner expanding mechanism 3, the lifting plate 27 rises to push the sliding hinged supports 312 to rise, so that the included angle between the first inclined rod 22 and the second inclined rod 29 is changed, so that the two inner formworks 310 are pushed to be away from each other, and a hot mould ring can be squeezed together with the outer formwork 25, so that the hot mould ring is deformed.

Specifically, the external screw thread has all been seted up to the top outer wall of threaded rod 14 and No. two threaded rods 15, drive gear 18 is connected with driven gear 19 meshing, and the external screw thread of the top outer wall of threaded rod 14 and No. two threaded rods 15 and internal thread 28's structure looks adaptation can effectively transmit and support lifter plate 27.

Specifically, a first threaded rod 14 and a second threaded rod 15 are respectively embedded in the two internal threads 28, the lifting plate 27 is connected with the inner wall of the forging box 11 in a sliding manner, the lifting plate 27 is connected with the central shaft column 31 in a sliding manner, two outer formworks 25 jointly enclose a circular cavity, the position adjacent to the insertion hole 210 corresponds to the position of the insertion rod 211, the lifting movement of the lifting plate 27 is separated from the rotating movement of the central shaft column 31, so that the outer formwork 25 is fixed, the inner formwork 310 rotates, the length of the third diagonal rod 39, the length of the fourth diagonal rod 313, the length of the first diagonal rod 22 and the length of the second diagonal rod 29 are the same, a compression die cavity is arranged between the inner die shell 310 and the outer die shell 25, and a third diagonal rod 39, a fourth diagonal rod 313, a first diagonal rod 22 and a second diagonal rod 29 which have the same length are arranged on the compression die cavity, the same height variation can be produced so that the outer formwork 25 and the inner formwork 310 are always in the same horizontal plane.

When in use, the annular hot mold is clamped by the three-axis manipulator and enters the taking and placing groove 12, so that the annular hot mold is placed on the upper side of the extension plate 26, the first motor 110 is started to drive the driving gear 18 to rotate, further, the first driven gear 19 is meshed, the first threaded rod 14 is driven, the first threaded rod 14 rotates and drives the second threaded rod 15 to rotate through the driving belt 17, under the screw driving action of the first threaded rod 14, the second threaded rod 15 and the internal thread 28, the lifting plate 27 can be effectively lifted, in the external expansion mechanism 2, the lifting plate 27 is lifted, the second hinged support 23 can be pushed to lift, further, the included angle between the first inclined rod 22 and the second inclined rod 29 is changed, two external formworks 25 are enabled to be close to each other, the inserted rod 211 is correspondingly inserted into the inserting hole 210, therefore, the splicing dislocation of the external formworks 25 is avoided, in the internal expansion mechanism 3, the lifting plate 27 is lifted, the sliding, and further changing the included angle between the first diagonal rod 22 and the second diagonal rod 29, further pushing the two inner formworks 310 to be away from each other, and extruding a hot mold ring together with the outer formwork 25, so that the hot mold ring is deformed, then, starting the second motor 35 to drive the secondary gear 36 to rotate, the secondary gear 36 being meshed with the transmission main gear 32 to rotate, so that the central axis column 31 rotates, in the rotation process of the central axis column 31, the inner formwork 310 can rotate along the inner wall of the hot mold ring and can effectively extrude the deformation of the hot mold ring, so that the hot mold ring extrudes a molded hub on the inner formwork 310 and the outer formwork 25, similarly, after the second motor 35 is turned off, controlling the output shaft of the first motor 110 to rotate reversely, so that the inner formworks 310 are close to each other, the outer formworks 25 are away from each other, the molded hub can be exposed, and the three-axis manipulator clamps the molded hub, and stands and cools.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and the embodiments and descriptions given above are only illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A forging method for a new energy automobile hub comprises the following steps:

s2, placing the quenched alloy blank into a taking and placing groove (12) in a forging device, placing an annular hot die on the upper side of an extension plate (26), starting a first motor (110), driving a driving gear (18) to rotate, further engaging a transmission driven gear (19), driving a first threaded rod (14), enabling the first threaded rod (14) to rotate and driving a second threaded rod (15) to rotate through a transmission belt (17), and effectively lifting a lifting plate (27) under the screw driving action of the first threaded rod (14), the second threaded rod (15) and an internal screw (28) so as to integrally form a wheel hub steel ring;

the forging device in S2 comprises a lifting mechanism (1), an external expanding mechanism (2) and an internal expanding mechanism (3), and is characterized in that the lifting mechanism (1) is internally provided with the external expanding mechanism (2) and the internal expanding mechanism (3), and the internal expanding mechanism (3) is sleeved in the external expanding mechanism (2).

2. The forging method of the new energy automobile hub according to claim 1, characterized by comprising the following steps: the lifting mechanism (1) comprises a forging box (11), a taking and placing groove (12), a bottom box (13), a threaded rod (14), a second threaded rod (15), a belt pulley (16), a transmission belt (17), a driving gear (18), a driven gear (19) and a motor (110), wherein the taking and placing groove (12) is formed in the middle of the upper side of the forging box (11), the bottom box (13) is fixedly connected to the bottom wall of the forging box (11), the first threaded rod (14) and the second threaded rod (15) are rotatably embedded in the bottom box (13), the bottom ends of the first threaded rod (14) and the second threaded rod (15) are rotatably connected with the bottom wall of the forging box (11) through bearings, the outer walls of the bottom ends of the first threaded rod (14) and the second threaded rod (15) are fixedly sleeved with the belt pulley (16), and the transmission belt (17) is connected between the two belt pulleys (16), fixed cover on the outer wall of threaded rod (14) is equipped with driven gear (19), one side of threaded rod (14) and the upside screw fixation that is located bottom case (13) have motor (110), the output shaft of motor (110) passes bottom case (13) fixedly connected with drive gear (18).

3. The forging method of the new energy automobile hub according to claim 1, characterized by comprising the following steps: the external expanding mechanism (2) comprises a first hinged support (21), a first diagonal rod (22), a second hinged support (23), a third hinged support (24), an external formwork (25), an extension plate (26), a lifting plate (27), internal threads (28), a second diagonal rod (29), a jack (210) and an insert rod (211), wherein the lifting plate (27) is positioned in the forging box (11), the lifting plate (27) is symmetrically provided with two internal threads (28), the first hinged support (21) is fixedly connected above the lifting plate (27) and on the opposite inner wall of the forging box (11), the second hinged support (23) is fixedly connected on the upper side of the two ends of the lifting plate (27), the two external formworks (25) are arranged on the upper opposite side of the lifting plate (27) and in the taking and placing groove (12), the third hinged support (24) is fixedly connected on one side, far away from each other, of the two external formworks (25), no. three free bearing (24) and No. two have articulated between free bearing (23) to have No. two down tubes (29), it has one down tube (22) to articulate between a free bearing (21) and No. three free bearing (24), two jack (210) have all been seted up to the adjacent side of outer mould shell (25), two equal fixedly connected with inserted bar (211) of the adjacent side of outer mould shell (25).

4. The forging method of the new energy automobile hub according to claim 1, characterized by comprising the following steps: the internal expanding mechanism (3) comprises a central shaft column (31), a main gear (32), a connecting cylinder (33), a limiting ring (34), a second motor (35), a pinion (36), a rotating shaft (37), a fourth hinged support (38), a third inclined rod (39), an internal mold shell (310), a sliding chute (311), a sliding hinged support (312), a fourth inclined rod (313) and a fifth hinged support (314), wherein the central shaft column (31) is embedded in the upper side of the middle part of the bottom case (13), the main gear (32) is fixedly sleeved on the outer wall of the bottom end of the central shaft column (31), the connecting cylinder (33) is fixedly connected on the upper side of the main gear (32) and positioned on the outer side of the central shaft column (31), the limiting ring (34) is fixedly sleeved on the outer wall of the top end of the connecting cylinder (33), the limiting ring (34) is rotatably connected with the bottom case (13) through a bearing, the second motor (35) is fixed on the upper side of the bottom case (13) and positioned on one side of the central shaft column (31), the output shaft of No. two motor (35) passes under casing (13) fixedly connected with pinion (36), lifter plate (27) are passed on the top of center pedestal (31), two No. four free bearings (38) of top outer wall fixedly connected with of center pedestal (31), two spout (311) have been seted up to the middle part outer wall of center pedestal (31), all inlay in spout (311) and be equipped with slip free bearing (312), the both sides of center pedestal (31) all are equipped with interior mould shell (310), the equal fixedly connected with No. five free bearings (314) of the adjacent side of interior mould shell (310), all articulate between No. five free bearings (314) and No. four free bearings (38) and have No. three down tube (39), it has No. four down tube (313) all to articulate between slip free bearing (312) and No. five free bearings (314).

5. The forging method of the new energy automobile hub according to claim 2, characterized by comprising the following steps: external threads are formed in the outer walls of the top ends of the first threaded rod (14) and the second threaded rod (15), and the driving gear (18) is meshed with the driven gear (19) and is connected with the driven gear.

6. The forging method of the new energy automobile hub according to claim 3, characterized by comprising the following steps: a first threaded rod (14) and a second threaded rod (15) are respectively embedded in the two internal threads (28), the lifting plate (27) is in sliding connection with the inner wall of the forging box (11), the lifting plate (27) is in sliding connection with the central shaft column (31), two outer formworks (25) jointly enclose a circular cavity, and the position of the adjacent jack (210) corresponds to the position of the inserted rod (211); the length of the third diagonal rod (39), the length of the fourth diagonal rod (313), the length of the first diagonal rod (22) and the length of the second diagonal rod (29) are the same, and a compression mold cavity is arranged between the inner mold shell (310) and the outer mold shell (25).