阅读说明：本技术 变速箱链轮粉末冶金加工工艺 (powder metallurgy processing technology for gearbox sprocket ) 是由 雷相兵 黄振 王正举 邵轶松 于 2019-10-21 设计创作，主要内容包括：本发明公开了一种变速箱链轮粉末冶金加工工艺,包括成形、烧结、整形、热处理和机械加工工序,成形工序采用的成形模具包括成形上模和成形下模,整形工序采用的整形模具包括整形上模和整形下模,成形下模包括竖向延伸的成形中芯棒,在成形中芯棒上套设有下三冲,在下三冲上套设有下二冲,在下二冲上套设有下一冲,在下一冲上固套有成形阴模,成形上模包括上二冲和固套在上二冲上的上一冲,整形下模包括整形中芯棒,在整形中芯棒上套设有下冲,整形上模包括上冲。针对应用于变速箱的带有外花键轴的链轮,利用本模具能够一次压制成形,有效提高生产效率；能够对烧结后的链轮进行整形,纠正烧结过程中出现的微小变形,提高产品质量。(The invention discloses a gearbox sprocket wheel powder metallurgy processing technology which comprises the working procedures of forming, sintering, shaping, heat treatment and machining, wherein a forming die adopted in the forming working procedure comprises an upper forming die and a lower forming die, the shaping die adopted in the shaping working procedure comprises an upper shaping die and a lower shaping die, the lower forming die comprises a middle forming core rod which extends vertically, a lower three punch is sleeved on the middle forming core rod, a lower two punch is sleeved on the lower three punch, a lower punch is sleeved on the lower two punch, a forming female die is fixedly sleeved on the lower punch, the upper forming die comprises an upper two punch and an upper punch which is fixedly sleeved on the upper two punch, the lower shaping die comprises a middle shaping core rod, a lower punch is sleeved on the middle shaping core rod, and the upper shaping die comprises an upper punch. Aiming at the chain wheel with the external spline shaft applied to the gearbox, the die can be used for one-time pressing forming, so that the production efficiency is effectively improved; the chain wheel after sintering can be shaped, the micro deformation in the sintering process can be corrected, and the product quality can be improved.)

1. The utility model provides a gearbox sprocket powder metallurgy processing technology, is including taking shape, sintering, plastic, thermal treatment and machining process, the forming die that the forming process adopted is including the shaping mould and the shaping lower mould that match each other, the shaping die that the shaping process adopted is including the shaping mould and the shaping lower mould that match each other, its characterized in that: the lower forming die comprises a vertically extending forming middle core rod (1), wherein a lower punch (3) is sleeved on the forming middle core rod (1), a lower punch (4) is sleeved on the lower punch (3), a lower punch (5) is sleeved on the lower punch (4), a forming female die (6) is fixedly sleeved on the lower punch (5), the forming female die (6), the forming middle core rod (1), the lower punch (3), the lower punch (4) and the lower punch (5) can slide up and down under the driving of respective power, inner teeth matched with a chain wheel spline are arranged on the inner wall of the lower punch (4), outer teeth meshed with the lower punch (4) are arranged on the outer wall of the lower punch (5), inner teeth matched with the chain wheel tooth form are arranged on the inner wall of the forming female die (6), and outer teeth meshed with the forming female die (6) are arranged on the outer wall of the lower punch (5), the forming upper die comprises an upper second punch (7) and an upper first punch (8) fixedly sleeved on the upper second punch (7), a through hole for a forming middle core rod (1) to penetrate through is formed in the center of the upper second punch (7), and external teeth meshed with a forming female die (6) are arranged on the outer wall of the upper first punch (8);

the shaping lower die comprises a shaping middle core rod (12), a lower punch (14) is sleeved on the shaping middle core rod (12), a shaping female die (19) is sleeved on the lower punch (14), the shaping middle core rod (12), the lower punch (14) and the shaping female die (19) can slide up and down under the driving of respective power, the diameter of the upper end of the shaping middle core rod (12) is gradually reduced from bottom to top, inner teeth matched with splines of a chain wheel are arranged on the inner wall of the shaping female die (19), and outer teeth meshed with the shaping female die (19) are arranged on the outer wall of the lower punch (14); the upper shaping die comprises an upper punch (15), and a vertical through hole for a shaping middle core rod (12) to penetrate through is formed in the center of the upper punch (15).

2. the gearbox sprocket powder metallurgy processing technology of claim 1, wherein: the lower extreme coaxial coupling of plug (1) has in taking shape plug connecting rod (2) in taking shape, in taking shape plug connecting rod (2), three down towards (3), two down towards (4) and the next respective lower extreme towards (5) is connected with first pressure pad (9) respectively, the first pressure pad (9) of three down towards (3), the first pressure pad (9) of two down towards (4) and the first pressure pad (9) of next towards (5) of plug connecting rod (2) distribute in proper order from the bottom up in the shaping, first pressure pad (9) of three down towards (3), first pressure pad (9) of two down towards (4), first pressure pad (9) of next towards (5) all are the basin structure of back-off, and respective lower extreme is connected with annular first clamping ring (10) respectively, three down towards the maximum diameter of first pressure pad (9) of (3), down, The maximum diameter of the first pressure pad (9) of the lower second punch (4) and the maximum diameter of the first pressure pad (9) of the lower second punch (5) are increased in sequence.

3. The gearbox sprocket powder metallurgy processing technology of claim 2, wherein: the lower ends of the middle forming mandrel connecting rod (2), the lower third punch (3), the lower second punch (4) and the lower first punch (5) are respectively provided with a circle of convex steps with the lower diameter larger than the upper diameter, the middle forming mandrel connecting rod (2), the lower third punch (3), the lower second punch (4) and the lower first punch (5) are respectively connected with the upper ends of respective first pressing pads (9) through first pressing covers (11), the centers of the first pressing covers (11) are respectively provided with corresponding step holes with the lower large and the upper small, the first pressing covers (11) are sleeved on the corresponding convex steps of the middle forming mandrel connecting rod (2), the lower third punch (3), the lower second punch (4) and the lower punch (5), and the first pressing covers (11) are connected with the corresponding first pressing pads (9) through bolts.

4. The gearbox sprocket powder metallurgy processing technology of claim 3, wherein: go up two and be connected with respectively in the upper end that dashes (7) and last one towards (8) first pressure pad (9), go up two and be the ascending basin column structure of opening with first pressure pad (9) that last one towards (8), just the maximum diameter that goes up two first pressure pads (9) that dash (7) is less than the maximum diameter that goes up first pressure pad (9) that dashes (8).

5. the gearbox sprocket powder metallurgy processing technology of claim 4, wherein: go up two and be provided with "protruding" shape step that the diameter of a lower part is less than the upper portion diameter respectively towards the upper end of (7) and last (8), go up two and be passed through respectively towards (7) and last (8) first gland (11) and link to each other with respective first pressure pad (9) lower extreme, each the center of first gland (11) all is provided with corresponding little big-end-up's step hole down, each first gland (11) cover is established on the "protruding" shape step that corresponds two last (7), last (8) towards, just links to each other with corresponding first pressure pad (9) through the bolt.

6. the gearbox sprocket powder metallurgy processing technology of claim 1, wherein: the lower end of the shaping middle core rod (12) is coaxially connected with a shaping middle core rod connecting rod (13), the lower end of the lower punch (14) and the upper end of the upper punch (15) are respectively connected with a second pressure pad (16), and the lower end of the second pressure pad (16) of the shaping middle core rod connecting rod (13), the lower end of the second pressure pad (16) of the lower punch (14) and the upper end of the second pressure pad (16) of the upper punch (15) are respectively connected with an annular second pressure ring (17).

7. the gearbox sprocket powder metallurgy processing technology of claim 6, wherein: the center of the shaping central core rod (12) is provided with a bolt counter bore (12a), and the upper end of the shaping central core rod connecting rod (13) is provided with a threaded hole matched with the bolt counter bore (12 a).

8. The gearbox sprocket powder metallurgy processing technology of claim 6, wherein: the outer edge of a second pressure pad (16) of the lower punch (14) is provided with a chamfer used for being connected with a second pressure ring (17), and the diameter of the second pressure pad (16) of the lower punch (14) is larger than that of the second pressure pad (16) of the shaping core rod connecting rod (13).

9. The gearbox sprocket powder metallurgy processing technology of claim 6, wherein: the shaping central mandrel connecting rod (13), the lower punch (14) and the upper punch (15) are respectively connected with a corresponding second pressure pad (16) through a second gland (18), the lower end of the shaping central mandrel connecting rod (13) and the lower end of the lower punch (14) are respectively provided with a convex step with the upper diameter smaller than the lower diameter, the centers of the second gland (18) of the shaping central mandrel connecting rod (13) and the second gland (18) of the lower punch (14) are respectively provided with a corresponding step hole with a small upper part and a large lower part, the upper end of the upper punch (15) is provided with a convex step with the upper diameter larger than the lower diameter, the center of the second gland (18) of the upper punch (15) is provided with a corresponding step hole with a large upper part and a small lower part, and each second gland (18) is sleeved on the corresponding convex step of the shaping central mandrel connecting rod (13), the lower punch (14) and the upper punch (15), and is connected with the corresponding second pressure pad (16) by bolts.

Technical Field

The invention belongs to the field of powder metallurgy processing technology, and particularly relates to a transmission sprocket wheel powder metallurgy processing technology.

background

powder metallurgy is a process technique for producing metal powder or metal powder (or a mixture of metal powder and nonmetal powder) as a raw material, and then forming and sintering the raw material to produce metal materials, composite materials and various products.

the chain wheel partially applied to the gearbox is provided with an external spline connecting shaft, the outer wall of the external spline shaft chain wheel is provided with chain wheel teeth and spline teeth, when the chain wheel is manufactured by adopting a powder metallurgy process, the spline of a green body needs to be machined by adopting a machining method after pressing is finished, the process is complex, the production efficiency is low, and meanwhile, the green body formed by pressing can generate micro deformation after being sintered, so that the product quality is influenced.

Disclosure of Invention

Aiming at the technical problems, the invention provides a powder metallurgy processing technology for a transmission chain wheel, which can directly machine and form the chain wheel, does not need to machine an external spline in a machining mode after pressing, reduces production procedures, effectively improves production efficiency, can correct micro deformation of the chain wheel after sintering, and improves product precision.

Therefore, the technical scheme adopted by the invention is as follows: a powder metallurgy processing technology for a transmission sprocket comprises the working procedures of forming, sintering, shaping, heat treatment and machining, wherein a forming die adopted by the working procedure of forming comprises an upper forming die and a lower forming die which are matched with each other, the shaping die adopted by the working procedure of shaping comprises an upper shaping die and a lower shaping die which are matched with each other, the lower forming die comprises a middle forming core rod which extends vertically, a lower three-punch is sleeved on the middle forming core rod, a lower two punch is sleeved on the lower three punch, a lower punch is sleeved on the lower two punch, a forming female die is fixedly sleeved on the lower punch, the forming female die, the middle forming core rod, the lower three punch, the lower two punch and the lower punch can slide up and down under the driving of respective power, inner teeth which are matched with a sprocket spline are arranged on the inner wall of the lower two punch, outer teeth which are meshed with the lower two punch are arranged on the outer wall of the lower three punch, the inner wall of the forming female die is provided with inner teeth matched with the tooth form of the chain wheel, the outer wall of the lower punch is provided with outer teeth meshed with the forming female die, the upper forming die comprises an upper punch and an upper punch fixedly sleeved on the upper punch, the center of the upper punch is provided with a through hole for a forming middle core rod to penetrate, and the outer wall of the upper punch is provided with outer teeth meshed with the forming female die;

The shaping lower die comprises a shaping middle core rod, a lower punch is sleeved on the shaping middle core rod, a shaping female die is sleeved on the lower punch, the shaping middle core rod, the lower punch and the shaping female die can slide up and down under the driving of respective power, the diameter of the upper end of the shaping middle core rod is gradually reduced from bottom to top, inner teeth matched with the chain wheel spline are arranged on the inner wall of the shaping female die, and outer teeth meshed with the shaping female die are arranged on the outer wall of the lower punch; the shaping upper die comprises an upper punch, and the center of the upper punch is provided with a vertical through hole for a shaping core rod to penetrate through.

Preferably, the lower end of the middle forming mandrel is coaxially connected with a middle forming mandrel connecting rod, the lower ends of the middle forming mandrel connecting rod, the lower three-punch, the lower two-punch and the lower punch are respectively connected with first pressure pads, the first pressure pad of the middle forming mandrel connecting rod, the first pressure pad of the lower three-punch, the first pressure pad of the lower two-punch and the first pressure pad of the lower one-punch are sequentially distributed from bottom to top, the first pressure pad of the lower three-punch, the first pressure pad of the lower two-punch and the first pressure pad of the lower one-punch are all in inverted basin-shaped structures, the lower ends of the first pressure pad of the lower three-punch, the maximum diameter of the first pressure pad of the lower two-punch and the maximum diameter of the first pressure pad of the lower one-punch are sequentially increased. By adopting the structure, the structure arrangement is reasonable, the middle core rod, the lower third punch, the lower second punch and the lower punch are conveniently formed and are respectively connected with the respective driving mechanisms, and the first pressing pad is of a basin-shaped structure, so that the punching amount can be reduced, and the lower third punch, the lower second punch and the lower punch are more uniformly stressed and are not easy to deform.

Preferably, the lower ends of the forming central mandrel connecting rod, the lower three punches, the lower two punches and the lower one punch are respectively provided with a circle of convex steps with the lower diameter larger than the upper diameter, the forming central mandrel connecting rod, the lower three punches, the lower two punches and the lower one punch are respectively connected with the upper ends of the respective first press pads through first press covers, the centers of the first press covers are respectively provided with corresponding step holes with the lower large ends and the upper small ends, the first press covers are sleeved on the corresponding convex steps of the forming central mandrel connecting rod, the lower three punches, the lower two punches and the lower one punch, and the first press covers and the corresponding first press pads are connected through bolts. By adopting the structure, the connecting structure between the lower third punch, the lower second punch, the lower first punch and the corresponding first pressure pad is stable and reliable, is not easy to loosen and fall off, and is convenient to mount and dismount.

preferably, the upper ends of the upper second punch and the upper first punch are respectively connected with the first pressure pads, the first pressure pads of the upper second punch and the upper first punch are of basin-shaped structures with upward openings, and the maximum diameter of the first pressure pads of the upper second punch is smaller than that of the first pressure pads of the upper first punch. The two punches and the first punch are convenient to be connected with the driving mechanism, and the first pressure pad adopts a basin-shaped structure to reduce the punching amount, so that the two punches and the first punch are more uniformly stressed and are not easy to deform.

Preferably, the upper ends of the upper second punch and the upper first punch are respectively provided with a circle of convex steps with the lower diameter smaller than the upper diameter, the upper second punch and the upper first punch are respectively connected with the lower ends of the respective first press pads through the first press covers, the center of each first press cover is provided with a corresponding step hole with a smaller lower part and a larger upper part, and each first press cover is sleeved on the corresponding convex steps of the upper second punch and the upper first punch and is connected with the corresponding first press pads through bolts. By adopting the structure, the connection structure between the upper punch and the corresponding first pressure pad is stable and reliable, is not easy to loosen and fall off, and is convenient to mount and dismount.

Preferably, the lower end of the shaping mandrel is coaxially connected with a shaping mandrel connecting rod, the lower end of the lower punch and the upper end of the upper punch are respectively connected with a second pressing pad, and the lower end of the second pressing pad of the shaping mandrel connecting rod, the lower end of the lower punch and the upper end of the second pressing pad of the upper punch are respectively connected with an annular second pressing ring. By adopting the structure, the second pressing pad and the second pressing ring are convenient for connecting the shaping middle core rod, the lower punch and the upper punch with the corresponding driving mechanisms respectively, so that the shaping middle core rod, the lower punch and the upper punch are stressed uniformly.

Preferably, a bolt counter bore is formed in the center of the shaping core rod, and a threaded hole matched with the bolt counter bore is formed in the upper end of the shaping core rod connecting rod. By adopting the structure, the shaping middle core rod is conveniently in threaded connection with the shaping middle core rod connecting rod, and the connecting structure is stable and reliable.

Preferably, the outer edge of the second pressure pad of the lower punch is provided with a chamfer used for being connected with a second pressure ring, and the diameter of the second pressure pad of the lower punch is larger than that of the second pressure pad of the shaping core rod connecting rod. By adopting the structure, the arrangement of the chamfer angle can reduce the impulse on the lower punch, so that the lower punch is uniformly stressed and is not easy to deform; the change of the diameter of the second pressure pad makes the structural arrangement more reasonable, and is convenient for the connection of the mandrel connecting rod and each driving mechanism in the lower punching and shaping.

Preferably, the shaping middle core rod connecting rod, the lower punch and the upper punch are respectively connected with corresponding second press pads through second press covers, the lower end of the shaping middle core rod connecting rod and the lower end of the lower punch are respectively provided with a convex step with the upper diameter smaller than the lower diameter, the centers of the second press cover of the shaping middle core rod connecting rod and the second press cover of the lower punch are respectively provided with corresponding step holes with the smaller upper part and the larger lower part, the upper end of the upper punch is provided with a convex step with the upper diameter larger than the lower diameter, the center of the second press cover of the upper punch is provided with a corresponding step hole with the larger upper part and the smaller lower part, and each second press cover is sleeved on the corresponding convex step of the shaping middle core rod connecting rod, the lower punch and the upper punch and is connected with the corresponding second press pad through bolts. By adopting the structure, the step hole of the second gland is limited to the corresponding step structures of the shaping middle core rod connecting rod, the lower punch and the upper punch, and the second gland can be effectively prevented from falling off.

The invention has the beneficial effects that: aiming at the chain wheel with the external spline shaft applied to the gearbox, the die can be pressed and formed at one time, and the spline is not required to be machined on a green blank by a mechanical machining method at the later stage, so that the working procedures are reduced, the energy is saved, and the production efficiency is effectively improved; the sintered chain wheel can be shaped, the micro deformation in the sintering process can be corrected, and the product quality can be improved; the diameter of the upper end of the core rod is gradually reduced from bottom to top in the shaping process, so that the chain wheel can be conveniently placed, and the levelness of the chain wheel after being placed can be effectively guaranteed.

Drawings

FIG. 1 is a schematic structural view of a forming die;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is an enlarged view of portion B of FIG. 1;

FIG. 4 is a top view of the lower second punch;

FIG. 5 is a top view of the lower triple punch;

FIG. 6 is a top view of the forming cavity block;

FIG. 7 is a top view of the next punch;

FIG. 8 is a top view of the top punch;

FIG. 9 is a schematic structural view of a sizing die;

FIG. 10 is a schematic structural view of a female shaping mold;

FIG. 11 is a schematic diagram of an undershoot.

Detailed Description

The invention will be further illustrated by the following examples in conjunction with the accompanying drawings:

As shown in fig. 1 to 11, a transmission sprocket powder metallurgy processing technology mainly comprises the working procedures of forming, sintering, shaping, heat treatment and machining, wherein the forming procedure is to adopt a press to press and form metal powder in a forming die at one time, and the shaping procedure is to adopt the press to shape a pressed and formed blank body through a shaping die, correct micro deformation in the sintering process and improve the product quality.

As shown in fig. 1 to 8, a forming die adopted in a forming process comprises an upper forming die and a lower forming die which are matched with each other, the lower forming die comprises a middle forming core rod 1 which extends vertically, the cross section of the middle forming core rod 1 is circular, a lower three punch 3 is sleeved on the middle forming core rod 1, a lower two punch 4 is sleeved on the lower three punch 3, a lower punch 5 is sleeved on the lower two punch 4, a forming female die 6 is fixedly sleeved on the lower punch 5, the forming female die 6, the middle forming core rod 1, the lower three punch 3, the lower two punch 4 and the lower three punch 5 can slide up and down under the driving of respective power, the lower three punch 3, the lower two punch 4 and the lower punch 5 are all in a cylindrical structure, inner teeth which are matched with splines of a sprocket wheel are arranged on the inner wall of the lower two punch 4, spline teeth which are used for forming the sprocket wheel in a pressing process, outer teeth which are meshed with the lower two punch 4 are arranged on the outer wall of the lower three punch 5, inner teeth which are matched with the sprocket wheel are, the sprocket teeth used for forming the sprocket in the pressing process, the outer wall of the next punch 5 is provided with outer teeth meshed with a forming female die 6, the forming upper die comprises an upper punch 7 and an upper punch 8 fixedly sleeved on the upper punch 7, the center of the upper punch 7 is provided with a through hole for a forming middle core rod 1 to penetrate, the upper punch 8 is of a cylindrical structure, the outer wall of the upper punch 8 is provided with outer teeth meshed with the forming female die 6, the right side is a schematic structural diagram of the forming lower die in figure 1, the relative position schematic diagram of the forming female die 6 before punching, the forming middle core rod 1, the lower punch 3, the lower punch 4 and the next punch 5 is arranged on the right side, the relative position schematic diagram of the forming female die 6 after punching, the forming middle core rod 1, the lower punch 3, the lower punch 4 and the next punch 5 is arranged on the left side, the forming female die 6, the forming middle core rod 1, the lower punch 3, the lower punch 4 and the next punch 5 are respectively driven by oil cylinders, before stamping, metal powder is placed into gaps between a forming middle core rod 1 and a lower third punch 3, a lower second punch 4, a lower first punch 5 and a forming female die 6, an upper second punch 7 and an upper first punch 8 move downwards under the driving of a stamping machine in the stamping process, the forming female die 6, the forming middle core rod 1, the lower third punch 3, the lower second punch 4 and the lower first punch 5 respectively move according to set displacement under the driving of an oil cylinder to finish the stamping, and finally the lower third punch 3, the lower second punch 4 and the lower first punch 5 move upwards under the driving of the oil cylinder to enable a chain wheel formed by the stamping to be demoulded.

As shown in fig. 1, the lower end of a middle forming mandrel 1 is coaxially connected with a middle forming mandrel connecting rod 2, the lower ends of the middle forming mandrel connecting rod 2, the lower third punch 3, the lower second punch 4 and the lower first punch 5 are respectively connected with a first pressing pad 9, the first pressing pad 9 of the middle forming mandrel connecting rod 2, the first pressing pad 9 of the lower third punch 3, the first pressing pad 9 of the lower second punch 4 and the first pressing pad 9 of the lower first punch 5 are sequentially distributed from bottom to top, the first pressing pad 9 of the middle forming mandrel connecting rod 2 is in a cylindrical structure, the first pressing pad 9 of the lower third punch 3, the first pressing pad 9 of the lower second punch 4 and the first pressing pad 9 of the lower punch 5 are in an inverted basin-shaped structure, the lower ends of the first pressing pad 9 are respectively connected with an annular first pressing ring 10, the first pressing ring 10 has a certain deformation and plays a role of buffering, the maximum diameter of the first pressing pad 9 of the lower third punch 3 and the maximum diameter of the first pressing pad 9 of the lower second punch 4 are respectively connected with a certain deformation amount, The largest diameter of the first pressure pad 9 of the next punch 5 increases in turn.

As shown in fig. 1, the outer walls of the lower ends of the middle forming mandrel connecting rod 2, the lower third punch 3, the lower second punch 4 and the lower second punch 5 are respectively provided with a circle of convex steps with the lower diameter larger than the upper diameter, the middle forming mandrel connecting rod 2, the lower third punch 3, the lower second punch 4 and the lower second punch 5 are respectively connected with the upper ends of the respective first pressing pads 9 through first pressing covers 11, the center of each first pressing cover 11 is provided with a corresponding step hole with a larger lower part and a smaller upper part, each first pressing cover 11 is sleeved on the corresponding convex steps of the middle forming mandrel connecting rod 2, the lower third punch 3, the lower second punch 4 and the lower punch 5, and can effectively prevent falling off, and each first pressing cover 11 is connected with the corresponding first pressing pad 9 through a bolt.

As shown in fig. 1, the upper ends of the upper two punches 7 and the upper one punch 8 are respectively connected with a first pressure pad 9, the upper two punches 7 and the first pressure pad 9 of the upper one punch 8 are in basin-shaped structures with upward openings, and the maximum diameter of the first pressure pad 9 of the upper two punches 7 is smaller than that of the first pressure pad 9 of the upper one punch 8.

as shown in fig. 1, the upper ends of the upper second punch 7 and the upper first punch 8 are respectively provided with a circle of convex steps with the lower diameter smaller than the upper diameter, the upper second punch 7 and the upper first punch 8 are respectively connected with the lower ends of the respective first pressure pads 9 through first press covers 11, the center of each first press cover 11 is provided with a corresponding step hole with a smaller lower part and a larger upper part, and each first press cover 11 is sleeved on the corresponding convex steps of the upper second punch 7 and the upper first punch 8 and is connected with the corresponding first pressure pad 9 through bolts.

As shown in fig. 9, 10 and 11, the shaping die used in the shaping process comprises an upper shaping die and a lower shaping die which are matched with each other, the lower shaping die comprises a middle shaping mandrel 12, a lower punch 14 is sleeved on the middle shaping mandrel 12, a shaping female die 19 is sleeved on the lower punch 14, the middle shaping mandrel 12, the lower punch 14 and the shaping female die 19 can slide up and down under the driving of respective power, the diameter of the upper end of the middle shaping mandrel 12 is gradually reduced from bottom to top, inner teeth matched with splines of a sprocket are arranged on the inner wall of the shaping female die 19, and outer teeth meshed with the shaping female die 19 are arranged on the outer wall of the lower punch 14; the shaping upper die comprises an upper punch 15, and the center of the upper punch 15 is provided with a vertical through hole for the shaping middle core rod 12 to penetrate through. Referring to the structural schematic diagram of the shaping lower die in fig. 9, the right side is a schematic diagram of positions of a shaping middle core rod 12, a shaping female die 19 and a lower punch 14 before shaping, and the left side is a schematic diagram of positions of the shaping middle core rod 12, the shaping female die 19 and the lower punch 14 before shaping, a sprocket is sleeved on the shaping middle core rod 12 from the upper end of the shaping middle core rod 12, a spline at the lower part of the sprocket is just embedded into the shaping female die 19, then a punching machine is started, the upper punch 15 moves downwards to carry out shaping, and in the shaping process, the shaping middle core rod 12, the shaping female die 19 and the lower punch 14 move from right-side relative positions to left-side relative positions according to set displacements under.

As shown in fig. 9, the lower end of the shaping middle core rod 12 is coaxially connected with a shaping middle core rod connecting rod 13, the shaping middle core rod connecting rod 13 is convenient for connecting the shaping middle core rod 12 with the oil cylinder, the lower end of the shaping middle core rod connecting rod 13, the lower end of the lower punch 14 and the upper end of the upper punch 15 are respectively connected with a second pressure pad 16, the lower end of the second pressure pad 16 of the shaping middle core rod connecting rod 13, the lower end of the second pressure pad 16 of the lower punch 14 and the upper end of the second pressure pad 16 of the upper punch 15 are respectively connected with an annular second pressure ring 17, and the second pressure pad 16 and the second pressure ring 17 are convenient for connecting the shaping middle core rod connecting rod 13, the lower punch 14 and the upper punch 15 with the respective oil cylinder, so that the stress is more uniform, and the second pressure ring 17 has a certain deformation and plays a.

As shown in fig. 9, a bolt counter bore 12a is arranged at the center of the shaping central core rod 12, a threaded hole matched with the bolt counter bore 12a is arranged at the upper end of the shaping central core rod connecting rod 13, the shaping central core rod 12 and the shaping central core rod connecting rod 13 are connected through a bolt, and the connecting structure is stable and reliable.

As shown in fig. 9, the outer edge of the second pressure pad 16 of the lower punch 14 is provided with a chamfer for connecting with the second retainer 17, and the diameter of the second pressure pad 16 of the lower punch 14 is larger than that of the second pressure pad 16 of the connecting rod for shaping core rod 13.

As shown in fig. 9, the shaping middle core rod connecting rod 13, the lower punch 14 and the upper punch 15 are respectively connected with the corresponding second press pad 16 through the second gland 18, the lower end of the shaping middle core rod connecting rod 13 and the lower end of the lower punch 14 are respectively provided with a "convex" shaped step with the upper diameter smaller than the lower diameter, the centers of the second gland 18 of the shaping middle core rod connecting rod 13 and the second gland 18 of the lower punch 14 are respectively provided with a corresponding step hole with a small upper part and a large lower part, the upper end of the upper punch 15 is provided with a "convex" shaped step with the upper diameter larger than the lower diameter, the center of the second gland 18 of the upper punch 15 is provided with a corresponding step hole with a large upper part and a small lower part, each second gland 18 is sleeved on the corresponding "convex" shaped step of the shaping middle core rod connecting rod 13, the lower punch 14 and the upper punch 15, so as to effectively prevent falling off, each second gland 18 is connected with the corresponding, and is convenient to disassemble and assemble.