Die device for multi-station cold extrusion forming of hollow driving shaft

Abstract

The invention provides a die device for multi-station cold extrusion forming of a hollow driving shaft, and relates to the technical field of cold extrusion forming, the die device comprises a cold extrusion table, the cold extrusion table is provided with a forming mechanism facilitating cold extrusion of a seamless steel pipe, and the cold extrusion table is provided with an auxiliary mechanism assisting cold extrusion forming of the seamless steel pipe; the forming mechanism comprises a first cold extrusion station, a second cold extrusion station, a third cold extrusion station, a fourth cold extrusion station, a supporting vertical frame, a second guide frame and stamping equipment; and the auxiliary mechanism comprises a mounting support plate. According to the device, the first cold extrusion station, the second cold extrusion station, the third cold extrusion station and the fourth cold extrusion station are matched to perform cold extrusion on the seamless steel pipe, and through the matching effect of the four stations, when the seamless steel pipe is subjected to cold extrusion, the first cold extrusion station inhibits deformation of an inner hole of the seamless steel pipe; the second cold extrusion station guides layered flowing of metal, the third cold extrusion station reduces the folding defect, and the fourth cold extrusion station improves the contour definition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cold extrusion forming, more specifically, relates to a multi-station cold extrusion forming hollow drive shaft die device. BACKGROUND

[0002] Cold extrusion forming refers to a processing technology that uses a mold to apply a large pressure to a metal blank at room temperature, causing plastic deformation and flowing into the mold cavity, thereby obtaining a desired shape, size and performance of the workpiece. Its main functions include: realizing high-precision forming of complex parts, improving material utilization and production efficiency; improving the internal organization of the metal and enhancing the mechanical properties (such as strength and hardness) of the workpiece; reducing subsequent processing procedures and production costs, and is widely used in the manufacturing of precision parts in the fields of automobiles, machinery, electronics, etc.

[0003] The existing drive shaft workpiece has the following disadvantages when cold extrusion forming: Problems of solid bar utilization: When a solid bar is selected as the blank, the core needs to be removed through mechanical processing or other methods, resulting in low material utilization.

[0004] Cold extrusion process and station matching problems: The existing cold extrusion process of hollow drive shafts mostly uses single-station one-time forming cold extrusion method, which is difficult to fully consider various needs in the process of seamless pipe cold extrusion, such as being unable to effectively guide metal layering flow, reduce folding defects and improve profile clarity while suppressing inner hole deformation. Moreover, due to the inability to achieve integrated processing of hollow drive shafts, it is difficult to accurately control the outer diameter tolerance and the metal filling is not ideal, resulting in uneven product quality.

[0005] Metal deformation distribution problem: In the existing cold extrusion process of hollow drive shafts, the distribution of metal deformation among the processes is unreasonable, and it is also difficult to effectively control the single-station cross-sectional shrinkage and progressive upsetting, resulting in high risk of local stress concentration, uneven regional strain distribution, and large product hardness scatter, which makes it difficult to meet the process requirements of high-quality hollow drive shafts.

[0006] Mold temperature control problem: In the existing cold extrusion process of hollow drive shafts, the mold cooling method mostly uses full-system synchronous cooling, which lacks precise control. When cooling the mold cavity, precise cooling cannot be achieved due to synchronous cooling, resulting in a large amount of energy waste. The extensive cooling method cannot be targeted according to the temperature changes during cold extrusion of each station, and precise cooling cannot be achieved, which not only reduces the mold thermal management efficiency, but also affects the service life of the key components of the mold, increasing the production cost Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a multi-station cold extrusion die device for forming a hollow drive shaft to solve the above problems.

[0008] The hot pressing device of the present invention is a kind of hot pressing device for forming the hot pressing member of the hot pressing member, and the hot pressing device is a kind of pressure-sensitive adhesive tape, and the pressure-sensitive adhesive tape is a kind of pressure-sensitive adhesive tape. A water tank, at least two cooling coils are fixedly installed on the side end of the cooling water tank, each of the cooling coils is respectively connected to the circumferential end of the first cold extrusion station, the second cold extrusion station, the third cold extrusion station and the fourth cold extrusion station, the inner wall of the cooling water tank is provided with a plurality of water pumps, the upper end of each cooling water tank is fixedly connected to the water pump, the side ends of the first cold extrusion station, the second cold extrusion station, the third cold extrusion station and the fourth cold extrusion station are fixedly installed with a temperature detector, the side end of the support frame on one side is fixedly installed with a PLC controller, a first guide frame is fixedly installed between the two support frames, a movable plate is fixedly installed on the first guide frame, a cylinder is fixedly installed between each mounting support plate and the movable plate, two arc-shaped clamping plates are provided on the side end of each mounting support plate, a laser centering sensor is fixedly installed on the upper end of each mounting support plate, a guide rod is provided on the side end of the second guide frame, and each stamping equipment is fixedly installed on the guide rod.

[0009] Preferably, each of the stamping devices is located directly above the first cold extrusion station, the second cold extrusion station, the third cold extrusion station and the fourth cold extrusion station, respectively, and a motor is fixedly installed on the upper end of the stamping device.

[0010] Preferably, the stamping equipment is provided with a stamping head.

[0011] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, a laser centering sensor is provided, and the mounting support plate and the arc-shaped clamping plate are coordinated. When the arc-shaped clamping plate clamps the seamless steel pipe, the laser centering sensor is provided to detect and calibrate the position deviation of the seamless steel pipe in real time, thereby effectively assisting the precise positioning of the arc-shaped clamping plate on the mounting support plate. This design reduces the risk of uneven metal flow caused by blank offset, improves the coaxiality consistency of each step of the forging, and reduces subsequent finishing processes.

[0012] In the present invention, the seamless steel pipe is cold extruded by providing a first cold extrusion station, a second cold extrusion station, a third cold extrusion station and a fourth cold extrusion station. Through the cooperation of the four stations, when the seamless steel pipe is cold extruded, the first cold extrusion station suppresses the deformation of the inner hole of the seamless steel pipe, the second cold extrusion station guides the metal to flow in layers, the third cold extrusion station reduces folding defects, and the fourth cold extrusion station 23 improves the contour clarity. Through continuous forming at the four stations, the integrated processing of the hollow drive shaft is realized, the outer diameter tolerance is stabilized within ±0.1mm, and the metal filling fullness is improved.

[0013] In the present invention, by arranging multiple stations for coordination, the first cold extrusion station, the second cold extrusion station, the third cold extrusion station and the fourth cold extrusion station are designed for step-by-step forming, so as to realize diameter reduction → composite extrusion → upsetting → finishing, so that the metal deformation amount is reasonably distributed in each process, and by controlling the cross-sectional shrinkage rate and progressive upsetting of a single station, the risk of local stress concentration is reduced, the strain distribution in this area is uniform, and the process goal of small hardness dispersion is supported.

[0014] In the present invention, cooling coils are provided on the outsides of the first cold extrusion station, the second cold extrusion station, the third cold extrusion station and the fourth cold extrusion station, and real-time monitoring is performed by a temperature detector to cool the local high-temperature area. By controlling the cooling water flow rate, the temperature rise of the mold surface is suppressed, which helps to maintain the hardness stability of the first cold extrusion station, the second cold extrusion station, the third cold extrusion station or the fourth cold extrusion station, reduce the deformation of the cavity caused by thermal softening, and ensure the quality of cold extrusion of hollow seamless steel pipes.

[0015] In the present invention, an independent temperature detector is provided and used in conjunction with a cooling water tank. Based on the temperature detection reflection during cold extrusion at each workstation, the cooling water circulation is started only for the over-temperature mold cavity through the cooling coil, thereby avoiding the energy waste of synchronous cooling of the entire system, achieving precise cooling, optimizing the mold thermal management efficiency, and extending the service life of key components. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the cold extrusion station of the present invention; Figure 2 It is a structural schematic diagram of the support stand of the present invention; Figure 3It is the structural schematic diagram of the cooling water tank of the present application; Figure 4 It is the structural schematic diagram of the first cold extrusion station of the present application; Figure 5 It is the structural schematic diagram of the second guide frame of the present application; Figure 6 It is the structural schematic diagram of the stamping equipment of the present application; Figure 7 It is the structural schematic diagram of the PLC controller of the present application; Figure 8 It is the structural schematic diagram of the arc-shaped clamping plate of the present application.

[0017] In the figure, the corresponding relationship between the component names and the figure numbers is as follows: 1, cold extrusion table; 11, cooling water tank; 12, cooling coil; 2, first cold extrusion station; 21, second cold extrusion station; 22, third cold extrusion station; 23, fourth cold extrusion station; 24, temperature detector; 3, support stand; 31, PLC controller; 32, first guide frame; 33, movable plate; 4, mounting support plate; 41, arc-shaped clamping plate; 42, air cylinder; 43, laser centering sensor; 5, second guide frame; 51, guide rod; 6, stamping equipment; 61, motor; 62, stamping head. DETAILED DESCRIPTION

[0018] The embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0019] Please refer to Figure 1 - Figure 8 The present application provides a multi-station cold extrusion forming hollow drive shaft die device, which comprises a cold extrusion table 1, the cold extrusion table 1 is provided with a forming mechanism for facilitating cold extrusion of a seamless steel pipe, and the cold extrusion table 1 is provided with an auxiliary mechanism for assisting cold extrusion forming of the seamless steel pipe, the forming mechanism comprises a first cold extrusion station 2, a second cold extrusion station 21, a third cold extrusion station 22, a fourth cold extrusion station 23, a support stand 3, a second guide frame 5 and a stamping equipment 6, and the auxiliary mechanism comprises a mounting support plate 4. In the process of cold extrusion forming of the drive shaft, the raw material has an important influence on material utilization rate and manufacturing cost, and the device selects a seamless steel pipe for die casting. When the seamless steel pipe is cold extruded and formed, the seamless steel pipe is respectively placed on the inner side walls of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23, and each stamping equipment 6 reciprocates to cold extrude and form the seamless steel pipe, so as to die cast and form the seamless steel pipe; The first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 are all fixedly installed on the upper end of the cold extrusion platform 1. The first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 are all provided with an ejection mechanism. Before die-casting the seamless steel pipe, the seamless steel pipe can be placed in the first cold extrusion station 2, and the motor 61 is started to drive the punch head 62 to move downward. The punch head 62 will perform preliminary punching on the seamless steel pipe in the first cold extrusion station 2. After completing the punching of the initial station, the ejection mechanism in the first cold extrusion station 2 will eject the seamless steel pipe. After the initial station punching, the laser centering sensor can be used The device 43 locates the position of the seamless steel pipe, and the detection of the laser centering sensor 43 drives the cylinder 42 to extend and drive the installation support plate 4 to move. The installation support plate 4 drives the arc clamping plate 41 to move, and the arc clamping plate 41 clamps the seamless steel pipe punched in the first station. The movable plate 33 moves on the first guide frame 32 and drives the installation support plate 4 to move to the next station, the second cold extrusion station 21, so that the seamless steel pipe enters the second cold extrusion station 21. At this time, the movable plate 33 will drive the installation support plate 4 to move and reset, thereby reciprocating and driving the seamless steel pipe to enter the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 respectively for stamping. The support stand 3 is fixedly mounted on both sides of the upper end of the cold extrusion table 1, the mounting support plate 4 is located between the two support stands 3, the second guide frame 5 is fixedly mounted between the two support stands 3, and the stamping equipment 6 is located at the side end of the second guide frame 5. A cooling water tank 11 is fixedly mounted on the upper end of the cold extrusion table 1, and at least two cooling coils 12 are fixedly mounted on the side end of the cooling water tank 11. Each cooling coil 12 is respectively connected to the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station At the circumferential end of the pressing station 23, the inner side wall of the cooling water tank 11 is provided with multiple water pumps, the upper end of each cooling water tank 11 is fixedly connected to the water pump, the side ends of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 are fixedly installed with a temperature detector 24, the side end of the support stand 3 on one side is fixedly installed with a PLC controller 31, a first guide frame 32 is fixedly installed between the two support stands 3, and a movable plate 33 is fixedly installed on the first guide frame 32. A cylinder 42 is fixedly installed between each mounting support plate 4 and the movable plate 33, and two arc-shaped clamping plates 41 are provided on the side ends of each mounting support plate 4. A laser centering sensor 43 is fixedly installed on the upper end of each mounting support plate 4. When the seamless steel pipe is cold-extruded, a temperature detector 24 is provided on the outer sides of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23. Each temperature detector 24 can monitor the temperature of the first cold extrusion station 2, the second cold extrusion station 21, The temperatures of the third cold extrusion station 22 and the fourth cold extrusion station 23 are detected. When it is detected that the temperature of one of the cold extrusion stations exceeds a threshold value, the corresponding water pump in the cooling water tank 11 can be driven to pump cooling water into the cooling coil 12 to cool the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 or the fourth cold extrusion station 23. When the temperature detector 24 detects that the temperature drops below the threshold value, the corresponding water pump in the cooling water tank 11 can be driven to stop pumping, thereby stopping cooling; A guide rod 51 is mounted on the side of the second guide frame 5. Each punching device 6 is fixedly mounted on this guide rod 51. Each punching device 6 is located directly above the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22, and the fourth cold extrusion station 23. A motor 61 is fixedly mounted on the upper end of each punching device 6. Each punching device 6 is equipped with a punch head 62. During the cold extrusion of seamless steel pipes, the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22, and the fourth cold extrusion station 23 are configured. The first cold extrusion station 2 uses forward extrusion for overall diameter reduction. The blank is then aligned with the Φ laser centering sensor 43. The diameter of the hole is reduced from 5mm to Φ34.1mm, and the core rod provides inner wall support to suppress the deformation of the aperture and control the stress of the inner wall. The second cold extrusion station 21 is a composite extrusion to form primary steps of Φ36.4mm and Φ53.8mm. Under the joint action of the core rod and the die cavity, the radial flow of the metal is more stable. The third cold extrusion station 22 is a positive extrusion + upsetting combined forming to form a main step of Φ63.8mm; due to the existence of the core rod, the stress distribution is more uniform, which effectively suppresses the annular folding and the expansion of the hole wall. The fourth cold extrusion station 23 forms a maximum outer diameter of Φ72.2mm through upsetting + finishing, and completes the overall contour finishing. The seamless steel pipe is cold extruded through four stations.

[0020] Working principle: The first step is to control the hardness dispersion within 20 HB and the overall tensile strength Rm below 800 MPa during the cold extrusion forming process of the drive shaft. The selection of raw materials has an important influence on the material utilization rate and manufacturing cost. This device uses seamless steel pipe for die casting. When seamless steel pipe is used as the blank, its basic dimensions are outer diameter Φ43.5mm, inner diameter Φ17.9mm, length 315mm, and material volume 388874mm. 3, with a mass of approximately 3052.66g, and a material utilization rate of over 90%. A comparison of solid and hollow bar stock shows that, under the same forging volume and structure conditions, hollow bar stock saves approximately 505.60g of material per piece compared to solid bar stock, a savings ratio of approximately 14.2%. Taking into account the annual output of this part is 150,000 pieces, the use of hollow seamless steel pipes instead of solid bars is expected to save a total material weight of 75.8 tons per year. When the seamless steel pipes are cold-extruded, they can be placed on the inner walls of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 respectively, and the seamless steel pipes are cold-extruded reciprocatingly through each stamping device 6 to die-cast the seamless steel pipes. After the drive shaft is cold-extruded, the total length of the part is about 274 mm, which is a medium-length drive shaft. The two ends are a combination of conical and cylindrical structures of different diameters. The middle part is a large-diameter cylinder (maximum Φ72.2), which transitions to an inward concave shape to form a continuous step structure. Transition fillets (R3~R5) are designed in multiple places to improve metal flow stability and avoid forming stress concentration.

[0021] In the second step, before die-casting the seamless steel pipe, the seamless steel pipe can be placed in the first cold extrusion station 2, and the motor 61 is started to drive the punch head 62 to move downward. The punch head 62 will perform preliminary punching on the seamless steel pipe in the first cold extrusion station 2. After completing the punching of the initial station, the ejection mechanism in the first cold extrusion station 2 will eject the seamless steel pipe. After the initial punching, the position of the seamless steel pipe can be located by the laser centering sensor 43. The detection of the laser centering sensor 43 drives the cylinder 42 to extend and drives the mounting support plate 4 to move. The mounting support plate 4 drives the arc clamping plate 41 to move, and the arc clamping plate 41 clamps the seamless steel pipe punched in the first station. The movable plate 33 moves on the first guide frame 32 to drive the mounting support plate 4 to move to the next station, the second cold extrusion station 21, so that the seamless steel pipe enters the second cold extrusion station 21. At this time, the movable plate 33 drives the mounting support plate 4 to move and reset, thereby reciprocating and driving the seamless steel pipe to enter the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 respectively for stamping. This device is equipped with a laser centering sensor 43, a mounting support plate 4, and a curved clamping plate 41. When the curved clamping plate 41 clamps the seamless steel pipe, the laser centering sensor 43 is set to detect and calibrate the position deviation of the seamless steel pipe in real time, effectively assisting in the precise positioning of the curved clamping plate 41 on the mounting support plate 4. This design reduces the risk of uneven metal flow caused by blank deviation, improves the coaxiality consistency of each step of the forging, and reduces the subsequent finishing process. In the third step, when cold extruding the seamless steel pipe, a first cold extrusion station 2, a second cold extrusion station 21, a third cold extrusion station 22 and a fourth cold extrusion station 23 are set. The first cold extrusion station 2 uses forward extrusion for overall diameter reduction, and the blank is reduced from Φ43.5mm to Φ34.1mm. The mandrel provides inner wall support to suppress aperture deformation and control inner wall stress. The second cold extrusion station 21 is a composite extrusion to form primary steps of Φ36.4mm and Φ53.8mm. Under the joint action of the mandrel and the die cavity, the radial flow of the metal is more stable. The third cold extrusion station 22 is a forward extrusion + upsetting combined forming to form a main step of Φ63.8mm; due to the presence of the mandrel, the stress distribution is more uniform, effectively suppressing annular folding and hole wall expansion. The fourth cold extrusion station 23 forms a maximum outer diameter of Φ72.2mm by upsetting + finishing, and completes the overall contour finishing. The seamless steel pipe is cold extruded through four stations; This device cold-extrudes the seamless steel pipe by setting up a first cold extrusion station 2, a second cold extrusion station 21, a third cold extrusion station 22 and a fourth cold extrusion station 23. Through the cooperation of the four stations, when cold extruding the seamless steel pipe, the first cold extrusion station 2 suppresses the deformation of the inner hole of the seamless steel pipe, the second cold extrusion station 21 guides the layered flow of metal, the third cold extrusion station 22 reduces folding defects, and the fourth cold extrusion station 23 improves the contour clarity. Through continuous forming of the four stations, the integrated processing of the hollow drive shaft is realized, the outer diameter tolerance is stabilized within ±0.1mm, and the metal filling fullness is improved.

[0022] This device is designed with multiple stations, including the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23, which are formed in steps to achieve diameter reduction → composite extrusion → upsetting → finishing. This allows the metal deformation to be reasonably distributed in each process. By controlling the cross-sectional shrinkage rate of a single station and progressive upsetting, the risk of local stress concentration is reduced. The strain distribution in this area is uniform, supporting the process goal of small hardness dispersion. In the fourth step, when the seamless steel pipe is cold extruded, a temperature detector 24 is set on the outside of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23. Each temperature detector 24 can detect the temperature of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23 in real time. When it is detected that the temperature of one of the cold extrusions exceeds the threshold, the corresponding water pump in the cooling water tank 11 can be driven to pump cooling water into the cooling coil 12 to cool the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 or the fourth cold extrusion station 23. When the temperature detector 24 detects that its temperature drops below the threshold, the corresponding water pump in the cooling water tank 11 can be driven to stop pumping, thereby stopping cooling; The device is provided with cooling coils 12 on the outside of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 and the fourth cold extrusion station 23, and performs real-time monitoring through a temperature detector 24 to cool the local high-temperature area. By controlling the cooling water flow, the temperature rise of the mold surface is suppressed, which helps to maintain the hardness stability of the first cold extrusion station 2, the second cold extrusion station 21, the third cold extrusion station 22 or the fourth cold extrusion station 23, reduce the deformation of the cavity caused by thermal softening, and ensure the quality of cold extrusion of hollow seamless steel pipes; This device is equipped with an independent temperature detector 24, which is used in conjunction with the cooling water tank 11. According to the temperature detection reflection during cold extrusion at each workstation, the cooling water circulation is started only for the over-temperature mold cavity through the cooling coil 12, thereby avoiding the energy waste of synchronous cooling of the entire system, achieving precise cooling, optimizing the mold thermal management efficiency, and extending the service life of key components.

[0023] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A multi-station cold extrusion die device for forming a hollow drive shaft, comprising a cold extrusion station (1), characterized in that: The cold extrusion table (1) is provided with a forming mechanism for facilitating cold extrusion of the seamless steel pipe, and the cold extrusion table (1) is provided with an auxiliary mechanism for assisting the cold extrusion forming of the seamless steel pipe; The forming mechanism comprises a first cold extrusion station (2), a second cold extrusion station (21), a third cold extrusion station (22), a fourth cold extrusion station (23), a support stand (3), a second guide frame (5) and a stamping device (6); the auxiliary mechanism comprises a mounting support plate (4); the first cold extrusion station (2), the second cold extrusion station (21), the third cold extrusion station (22) and the fourth cold extrusion station (23) are all fixedly mounted on the upper end of the cold extrusion table (1); the support stand (3) is fixedly mounted on both side ends of the upper end of the cold extrusion table (1); the mounting support plate (4) is located between the two support stands (3); the second guide frame (5) is fixedly mounted between the two support stands (3); and the stamping device (6) is located at the side end of the second guide frame (5).

2. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 1, characterized in that: A cooling water tank (11) is fixedly mounted on the upper end of the cold extrusion table (1), and at least two cooling coils (12) are fixedly mounted through the side ends of the cooling water tank (11).

3. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 2, characterized in that: Each of the cooling coils (12) is respectively connected around the circumferential ends of the first cold extrusion station (2), the second cold extrusion station (21), the third cold extrusion station (22) and the fourth cold extrusion station (23); a plurality of water pumps are provided on the inner side wall of the cooling water tank (11); and the upper end of each cooling water tank (11) is fixedly connected to the water pump.

4. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 3, characterized in that: Temperature detectors (24) are fixedly installed on the side ends of the first cold extrusion station (2), the second cold extrusion station (21), the third cold extrusion station (22), and the fourth cold extrusion station (23).

5. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 4, characterized in that: A PLC controller (31) is fixedly installed on the side end of the support stand (3) on one side, and a first guide frame (32) is fixedly installed between the two support stands (3).

6. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 5, characterized in that: A movable plate (33) is fixedly mounted on the first guide frame (32).

7. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 6, characterized in that: A cylinder (42) is fixedly installed between each mounting support plate (4) and the movable plate (33), two arc-shaped clamping plates (41) are provided at the side end of each mounting support plate (4), and a laser centering sensor (43) is fixedly installed at the upper end of each mounting support plate (4).

8. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 7, characterized in that: A guide rod (51) is provided at the side end of the second guide frame (5), and each of the punching devices (6) is fixedly mounted on the guide rod (51).

9. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 8, characterized in that: Each of the stamping devices (6) is located directly above the first cold extrusion station (2), the second cold extrusion station (21), the third cold extrusion station (22), and the fourth cold extrusion station (23), respectively. A motor (61) is fixedly mounted on the upper end of the stamping device (6).

10. A multi-station cold extrusion die device for forming a hollow drive shaft as claimed in claim 9, characterized in that: The punching device (6) is provided with a punching head (62).

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