Extrusion forming equipment and method for aluminum alloy automobile transmission shaft

Abstract

The invention relates to the technical field of metal extrusion, in particular to extrusion forming equipment and method for an aluminum alloy automobile transmission shaft. The extrusion forming equipment comprises a base and a mold base, a supporting base is installed on the top face of the base, a guide rail is installed at the top end of the supporting base, and a heat preservation assembly is slidably connected to the surface of the guide rail; the heat preservation assembly is used for wrapping a preheated aluminum bar, a square limiting seat is fixedly connected to the surface of the heat preservation assembly, a horizontal guide groove allowing the square limiting seat to horizontally move is formed in the surface of the guide rail in a matched mode, and a rotary guide groove allowing the square limiting seat to rotate is formed in the surface of the guide rail in a matched mode. The invention aims to solve the problem that when a preheated blank is conveyed to an extrusion die, the surface layer of the blank rapidly exchanges heat with the environment to rapidly dissipate heat, so that a remarkable temperature gradient is formed on the section of the blank, and the blank is subjected to non-uniform plastic deformation in the extrusion process.

Description

Technical Field

[0001] The present invention relates to the technical field of metal extrusion, and specifically provides an extrusion forming device and method for an aluminum alloy automotive drive shaft. Background Art

[0002] The extrusion forming device for an aluminum alloy automotive drive shaft is a special equipment that processes aluminum alloy billets into drive shaft parts through a high-pressure extrusion process. Its core is to use the powerful thrust of the extruder to make the heated aluminum alloy flow in the mold to form a workpiece with a specific shape. This device mainly consists of an extruder body, a mold system, a heating and temperature control system, a hydraulic transmission system, and a control system. The extruder body includes an extrusion cylinder, an extrusion rod, and a mold base, which are used to accommodate the billet and apply extrusion power. The mold system includes a die sleeve, a mandrel, etc., which determine the cross-sectional shape and inner hole size of the drive shaft. The heating system precisely controls the temperature of the billet and the mold to ensure the plasticity of the material. The hydraulic system provides high pressure to drive the extrusion rod, and the servo motor controls the extrusion speed, monitors parameters such as pressure and temperature in real time, and ensures the forming accuracy, forming an efficient automated production line, and becoming the core equipment for drive shaft manufacturing under the background of automotive lightweighting.

[0003] However, in the aluminum alloy extrusion forming process, the billet needs to be preheated to a specific temperature range in advance and then transported to the extrusion mold. However, when the preheated billet is transferred to the extrusion mold, its surface layer rapidly dissipates heat due to rapid heat exchange with the environment, such as air convection, contact conduction, etc., resulting in a significant temperature gradient in the billet cross-section. The outer layer temperature drops rapidly, and the inner layer still maintains a high temperature due to the lag of heat conduction. This non-uniformity of the internal and external temperature fields will cause the billet to exhibit non-uniform plastic deformation during the extrusion process. The outer layer lags in flow due to low temperature and high deformation resistance, while the inner layer is prone to excessive deformation due to high-temperature softening. Eventually, the extruded product shows uneven hardness distribution along the cross-section direction and may be accompanied by quality problems such as dimensional deviation, surface cracks, or internal tissue defects, seriously affecting the mechanical property consistency and service reliability of the product. Summary of the Invention

[0004] The purpose of the present invention is to provide an extrusion forming device and method for an aluminum alloy automotive drive shaft to solve the problem that when the preheated billet is transferred to the extrusion mold, its surface layer rapidly dissipates heat due to rapid heat exchange with the environment, resulting in a significant temperature gradient in the billet cross-section and causing non-uniform plastic deformation of the billet during the extrusion process.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] An extrusion molding device for an aluminum alloy automobile drive shaft, comprising a base and a die holder. A support seat is installed on the top surface of the base, and a guiding track is installed at the top end of the support seat. A heat preservation component is slidably connected to the surface of the guiding track, and the heat preservation component is used for wrapping the preheated aluminum rod. A square limiting seat is fixedly connected to the surface of the heat preservation component, and a horizontal guiding groove for the horizontal movement of the square limiting seat is cooperatively opened on the surface of the guiding track, and a rotating guiding groove for the rotation of the square limiting seat is cooperatively opened on the surface of the guiding track.

[0007] Preferably, the heat preservation component includes a heat preservation bracket and a heat preservation sleeve. The heat preservation sleeve is installed on the inner ring of the heat preservation bracket, and a jaw component is installed on the surface of the heat preservation bracket.

[0008] Preferably, an installation seat is installed at the top end of the die holder, and an annular induction heating coil is integrated inside the installation seat.

[0009] Preferably, an infrared thermometer is installed at the top end of the installation seat.

[0010] Preferably, a driving slider that can move horizontally is movably connected to the surface of the guiding track. A connecting plug is rotatably connected to the surface of the driving slider, and a clamping groove for the embedding of the connecting plug is cooperatively opened on the surface of the square limiting seat.

[0011] An extrusion molding method for an aluminum alloy automobile drive shaft is carried out by using the above-mentioned extrusion molding device for an aluminum alloy automobile drive shaft. The specific steps are as follows:

[0012] A. Make the opening of the heat preservation sleeve face the outlet of the preheating furnace, and push the aluminum rod preheated to the plastic state into the inside of the heat preservation sleeve.

[0013] B. Preheat the flexible jaws to a temperature close to that of the aluminum rod, start the jaw component, and clamp and fix the aluminum rod.

[0014] C. Transport the heat preservation component to the rotating guiding groove, and then drive the heat preservation component to rotate so that the opening direction of the heat preservation sleeve turns vertically downward and aligns with the die inlet.

[0015] D. Control the jaw component to release the clamping of the aluminum rod, so that the aluminum rod falls into the die, remove the heat preservation component, and then start the hydraulic system to drive the extrusion rod to extrude the aluminum rod to form the aluminum rod.

[0016] Preferably, during the process of the aluminum rod falling into the die, it first passes through the infrared thermometer. The infrared thermometer performs real-time scanning on the surface temperature of the aluminum rod, identifies the abnormal area where the temperature drop is ≥20°C, and feeds the detection signal back to the control system to generate a surface temperature cloud map of the aluminum rod.

[0017] Preferably, when the abnormal temperature area of the aluminum rod moves into the heating range of the ring-shaped induction heating coil, the control system triggers the ring-shaped induction heating coil to locally heat it.

[0018] Preferably, the loosening force of the clamping jaw assembly is controlled so that the residence time of the low-temperature area on the surface of the aluminum rod in the ring-shaped induction heating coil matches the heating requirement.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. By setting the heat preservation sleeve, the heat loss during the transfer of the aluminum rod is significantly reduced by blocking heat conduction and reducing convective heat dissipation;

[0021] 2. The infrared thermometer scans the surface of the aluminum rod in real time, identifies the abnormal area where the temperature drop is ≥ 20 °C, generates a temperature cloud map and marks the low-temperature position. The control system triggers the ring-shaped induction heating coil to locally heat the low-temperature area according to the cloud map data, solving the forming difficulty caused by insufficient local temperature;

[0022] 3. The whole process is automatically controlled. From the clamping, horizontal conveying, rotary positioning to the releasing and blanking of the aluminum rod, all are completed through the linkage of the electric drive mechanism and the control system, reducing the manual operation link and improving the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the whole of the present invention;

[0024] Figure 2 It is a schematic structural diagram of the mold base of the present invention;

[0025] Figure 3 It is a schematic structural diagram of the guiding track of the present invention;

[0026] Figure 4 For the present invention Figure 3 The enlarged view at A in;

[0027] Figure 5 It is a schematic structural diagram of a part of the guiding track of the present invention;

[0028] Figure 6 It is a schematic vertical sectional view of the driving slider and the connecting plug of the present invention;

[0029] Figure 7 It is a schematic structural diagram of a part of the square limit seat of the present invention;

[0030] Figure 8 It is a schematic diagram of the state of the horizontal conveying of the aluminum rod of the present invention;

[0031] Figure 9 It is a schematic structural diagram of the heat preservation bracket of the present invention.

[0032] In the figure: 1, base; 2, machine top; 3, guide post; 4, mold base; 5, mounting base; 6, infrared thermometer; 7, support base; 8, guide track; 9, horizontal guide groove; 10, rotary guide groove; 11, arc drive plate; 12, push block; 13, drive slider; 14, connecting plug; 15, card slot; 16, square limit seat; 17, heat preservation bracket; 18, drive motor; 19, transmission lead screw; 20, flexible jaw; 21, heat preservation sleeve. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] Please refer to Figures 1 to 9 , the present invention provides a technical solution.

[0035] An extrusion forming device for an aluminum alloy automobile drive shaft includes a base 1, a machine top 2 and a mold base 4. Four guide posts 3 are arranged in an array on the top end of the base 1. All four guide posts 3 pass through the mold base 4 and are connected. The machine top 2 is fixedly connected to the top end of the guide post 3. A hydraulic system and an extrusion rod are arranged on the machine top 2. The aluminum alloy ingot after surface cleaning is preheated to a plastic state. The extrusion rod pushes the blank through the preheated mold. The aluminum alloy flows under the constraint of the mold under high pressure, and the mandrel synchronously forms the inner hole. The formed drive shaft is pulled out evenly by the tractor and completes the preliminary processing after air cooling or water cooling.

[0036] A support base 7 is installed on the top surface of the base 1. A guide track 8 is installed on the top end of the support base 7. A heat preservation component is slidably connected to the surface of the guide track 8. The heat preservation component is used to wrap the preheated aluminum rod, and then is transported along the track of the guide track 8 to the upper part of the mold and the aluminum rod is put into the mold. By setting the heat preservation component, heat preservation protection of the preheated blank can be realized, and heat loss during the transfer process can be significantly reduced.

[0037] The heat preservation component includes a heat preservation bracket 17 and a heat preservation sleeve 21. The heat preservation sleeve 21 is installed in the inner circle of the heat preservation bracket 17. A jaw component is installed on the surface of the heat preservation bracket 17. The inside of the heat preservation sleeve 21 is used to accommodate the aluminum rod. When the aluminum rod is preheated in the preheating furnace, the opening of the heat preservation sleeve 21 faces the outlet of the preheating furnace. After the aluminum rod is preheated, it is pushed into the heat preservation sleeve 21, and then the jaw component on the surface of the heat preservation bracket 17 clamps the aluminum rod for fixation. According to needs, a preheating system is installed on the surface of the heat preservation bracket 17 to preheat the jaw component to avoid the influence of the low-temperature environment on the temperature of the aluminum rod.

[0038] The jaw assembly includes a flexible jaw 20, which is movably arranged on the surface of the heat preservation bracket 17. It realizes reciprocating movement through an electric driving mechanism, so as to complete the clamping action of the workpiece. For example, a transmission lead screw 19 is rotatably connected to the surface of the heat preservation bracket 17. The flexible jaw 20 is threadedly connected to the transmission lead screw 19. A driving motor 18 is installed on the surface of the heat preservation bracket 17. The output end of the driving motor 18 is coaxially and fixedly connected to the transmission lead screw 19. By starting the driving motor 18 to drive the transmission lead screw 19 to rotate, due to the action of screw transmission, the flexible jaw 20 will move linearly along the axis of the transmission lead screw 19 to clamp or release the aluminum rod.

[0039] A square limiting seat 16 is fixedly connected to the surface of the heat preservation assembly. The square limiting seat 16 is fixedly connected to the heat preservation bracket 17. A horizontal guide groove 9 for the horizontal movement of the square limiting seat 16 is formed on the surface of the guide track 8 in a matching manner, and a rotating guide groove 10 for the rotation of the square limiting seat 16 is formed on the surface of the guide track 8 in a matching manner. When the opening of the heat preservation sleeve 21 faces the outlet of the preheating furnace and receives the aluminum rod, the heat preservation assembly and the aluminum rod are driven to move to the area of the rotating guide groove 10 by the horizontal movement of the square limiting seat 16 along the track of the horizontal guide groove 9. Then the square limiting seat 16 rotates in the area of the rotating guide groove 10, so that the opening of the heat preservation sleeve 21 faces downward. Then the jaw assembly releases the clamping of the aluminum rod, and the aluminum rod falls downward into the mold. Note that the area position of the rotating guide groove 10 is coaxially aligned with the center of the opening on the mold.

[0040] A horizontally movable driving slider 13 is movably connected to the surface of the guide track 8. The driving slider 13 is driven by electrical equipment and moves horizontally along the horizontal guide groove 9. A connecting plug 14 is rotatably connected to the surface of the driving slider 13. A clamping groove 15 for the embedding of the connecting plug 14 is formed on the surface of the square limiting seat 16 in a matching manner. The connecting plug 14 and the square limiting seat 16 are coaxially arranged. When the driving slider 13 moves, it drives the square limiting seat 16 to move with it into the area of the rotating guide groove 10. Since the connecting plug 14 and the driving slider 13 are rotatably connected, the rotation action of the square limiting seat 16 in the rotating guide groove 10 is not restricted by the movement of the driving slider 13.

[0041] The inner ring of the rotating guide groove 10 is rotatably connected with an arc-shaped driving plate 11. Two pushing blocks 12 are fixedly connected to the surface of the arc-shaped driving plate 11. When the square limiting seat 16 moves into the area of the rotating guide groove 10, a corner of the square limiting seat 16 just moves into the space between the two pushing blocks 12. Then, the arc-shaped driving plate 11 is driven to rotate by a driving mechanism. For example, external teeth are fixedly connected to the outer ring of the arc-shaped driving plate 11, a gear is rotatably connected in the guiding track 8, the gear is meshed with the gear teeth, a motor is fixedly connected to the surface of the guiding track 8, and the output end of the motor is coaxially fixedly connected with the gear. By starting the motor to drive the gear to rotate, the gear drives the arc-shaped driving plate 11 to rotate through meshing transmission, so that the pushing block 12 rotates with the arc-shaped driving plate 11, and then the square limiting seat 16 is pushed to rotate around the coaxial axis.

[0042] An installation seat 5 is installed at the top end of the mold base 4. An annular induction heating coil is integrated inside the installation seat 5. An infrared thermometer 6 is installed at the top end of the installation seat 5. The installation seat 5 is arranged directly above the upper opening of the mold. During the process of the aluminum rod falling into the mold, it will pass through the infrared thermometer 6 and the installation seat 5 in sequence. The infrared thermometer 6 first conducts real-time detection on the surface temperature of the aluminum rod, identifies the area where the temperature drops significantly, and feeds the detection signal back to the control system. When the abnormal temperature area moves into the heating range of the installation seat 5, the annular induction heating coil is triggered to locally heat it. At the same time, the falling speed of the aluminum rod can be controlled by adjusting the clamping force of the jaw assembly, so that the heating area matches the movement rhythm.

[0043] An extrusion forming method for an aluminum alloy automobile drive shaft is as follows:

[0044] A. Make the opening of the heat preservation sleeve 21 face the outlet of the preheating furnace, and push the aluminum rod preheated to the plastic state into the inside of the heat preservation sleeve 21;

[0045] B. Preheat the flexible jaws 20 to a temperature close to that of the aluminum rod, start the jaw assembly, and clamp and fix the aluminum rod;

[0046] C. Transport the heat preservation assembly to the rotating guide groove 10, then drive the heat preservation assembly to rotate, so that the opening direction of the heat preservation sleeve 21 turns vertically downward and aligns with the mold inlet;

[0047] D. Control the jaw assembly to release the clamping of the aluminum rod, so that the aluminum rod falls into the mold, remove the heat preservation assembly, and then start the hydraulic system to drive the extrusion rod to extrude the aluminum rod to form it.

[0048] During the process of the aluminum rod falling into the mold, it first passes through the infrared thermometer 6. The infrared thermometer 6 conducts real-time scanning on the surface temperature of the aluminum rod, identifies the abnormal area where the temperature drop is ≥20 °C, and feeds the detection signal back to the control system to generate a surface temperature cloud map of the aluminum rod.

[0049] When the abnormal temperature area of the aluminum rod moves into the heating range of the ring induction heating coil, the control system triggers the ring induction heating coil to locally heat it.

[0050] Control the loosening force of the clamping jaw assembly so that the residence time of the low-temperature area on the surface of the aluminum rod in the ring induction heating coil matches the heating requirement.

[0051] The heat preservation sleeve 21 adopts a multi-layer composite heat insulation structure, such as an inner layer of reflective aluminum foil, a middle layer of ceramic fiber felt, and an outer layer of high-temperature resistant silica gel, to form a fully enclosed heat preservation cavity, and only an axial opening for docking with the outlet of the preheating furnace is reserved.

[0052] Preheat it to a temperature close to that of the blank before clamping the blank to avoid local heat conduction loss caused by the contact of the metal clamping jaws. The clamping action adopts a flexible contact design, and the contact surface of the clamping jaw is an arc-shaped silica gel pad to reduce the rigid contact area with the blank and reduce the heat bridge effect.

[0053] When the heat preservation assembly moves to the rotation guide groove 10 in the rotation area, the driving mechanism is used to turn the opening direction of the heat preservation sleeve 21 vertically downward. When the aluminum rod passes through the infrared thermometer 6, the built-in infrared temperature measurement array scans the surface temperature, identifies the abnormal area where the temperature drop is ≥20°C, and the detection signal is fed back to the control system in real time to generate a surface temperature cloud map of the blank, mark the specific position that needs to be heated, and the ring induction heating coil only locally heats the low-temperature area according to the temperature cloud map data.

[0054] Control the falling rhythm by the loosening force of the clamping jaw assembly so that the residence time of the low-temperature area in the heating coil matches the heating requirement.

[0055] The opening of the heat preservation sleeve 21 is aligned with the outlet of the preheating furnace. The aluminum rod is pushed into the heat preservation sleeve 21 by the pusher in the furnace, and the clamping jaw assembly synchronously tightens and fixes the aluminum rod. The heat preservation assembly moves uniformly along the horizontal guide groove 9. During this period, the preheating system maintains the temperature of the clamping jaws. The heat preservation sleeve 21 reduces the radiation heat dissipation through the material reflection and heat insulation characteristics. After reaching the rotation guide groove 10, the heat preservation assembly is driven to rotate so that the opening is vertically downward and aligned with the mold inlet. When the aluminum rod falls through the infrared thermometer 6, the detection is triggered. When it enters the mounting seat 5, the coil unit corresponding to the low-temperature area is automatically started, and after completing the local rapid heat supplement, it falls into the mold.

[0056] Through the above solutions, the problem of uneven heat dissipation during the transfer of aluminum alloy blanks can be systematically solved. In practical applications, the thickness of the heat preservation material, the speed of the transfer equipment, and the induction heating power can be flexibly adjusted according to the production capacity scale and blank specifications to achieve the balance between economy and performance.

[0057] The specific solution of this scheme is as follows: Preheat the aluminum rod to reach the plastic state, with the opening of the heat preservation sleeve 21 facing the outlet of the preheating furnace. After the aluminum rod is preheated, the pushing mechanism in the preheating furnace pushes the aluminum rod into the interior of the heat preservation sleeve 21. Start the electrical equipment of the jaw assembly to make the flexible jaw 20 move linearly and clamp and fix the aluminum rod. After clamping the aluminum rod, the square limit seat 16 fixedly connected to the surface of the heat preservation support 17 moves horizontally along the horizontal guide groove 9 opened on the surface of the guide track 8, driving the heat preservation assembly and the aluminum rod to move together until the aluminum rod is transported to the area of the rotary guide groove 10. When the square limit seat 16 moves into the area of the rotary guide groove 10, one of its corners just moves into the space between the two pushing blocks 12 on the surface of the arc-shaped driving plate 11. Start the driving mechanism to drive the arc-shaped driving plate 11 to rotate, so that the pushing block 12 rotates with the arc-shaped driving plate 11, and then pushes the square limit seat 16 to rotate around the coaxial axis, making the opening of the heat preservation sleeve 21 face downward. At this time, control the jaw assembly to release the clamping of the aluminum rod, and the aluminum rod falls downward into the mold under the action of gravity. During the process of the aluminum rod falling into the mold, it first passes through the infrared thermometer 6. The infrared thermometer 6 detects the surface temperature of the aluminum rod in real time, identifies the area where the temperature drops significantly, and feeds the detection signal back to the control system. When the abnormal temperature area moves into the heating range of the mounting seat 5, the control system triggers the annular induction heating coil inside the mounting seat 5 to locally heat it. At the same time, by adjusting the clamping force of the jaw assembly, the falling speed of the aluminum rod is controlled to make the heating area match the movement rhythm of the aluminum rod, realizing precise heating. After the aluminum rod falls into the mold, first remove the heat preservation assembly, then start the hydraulic system to drive the extrusion rod to move downward, push the aluminum rod through the preheated mold, the aluminum alloy flows under the constraint of the mold under high pressure, and the mandrel synchronously forms the inner hole. The formed transmission shaft is pulled out at a constant speed by the tractor. According to the process requirements, air cooling or water cooling is selected to cool the transmission shaft to complete the preliminary processing.

[0058] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An extrusion forming device for an aluminum alloy automobile drive shaft, comprising a base (1) and a die holder (4), characterized in that: A support base (7) is mounted on the top surface of the base (1). A guiding track (8) is mounted at the top end of the support base (7). A heat preservation component, which is used to wrap the preheated aluminum bar, is slidably connected to the surface of the guiding track (8). A square limiting seat (16) is fixedly connected to the surface of the heat preservation component. A horizontal guiding groove (9) for the horizontal movement of the square limiting seat (16) is cooperatively formed on the surface of the guiding track (8), and a rotating guiding groove (10) for the rotation of the square limiting seat (16) is cooperatively formed on the surface of the guiding track (8).

2. The extrusion forming equipment for an aluminum alloy automobile drive shaft according to claim 1, characterized in that, The heat preservation component includes a heat preservation support (17) and a heat preservation sleeve (21). The heat preservation sleeve (21) is mounted on the inner ring of the heat preservation support (17). A jaw component is mounted on the surface of the heat preservation support (17).

3. The extrusion forming device for an aluminum alloy automobile drive shaft according to claim 1, characterized in that An installation base (5) is mounted on the top end of the mold base (4). An annular induction heating coil is integrated inside the installation base (5).

4. The extrusion forming device for an aluminum alloy automobile drive shaft according to claim 3, characterized in that, An infrared thermometer (6) is mounted on the top end of the installation base (5).

5. The extrusion forming device for an aluminum alloy automobile drive shaft according to claim 1, characterized in that, A driving slider (13) capable of horizontal movement is movably connected to the surface of the guiding track (8). A connecting plug (14) is rotatably connected to the surface of the driving slider (13). A clamping groove (15) for the embedding of the connecting plug (14) is cooperatively formed on the surface of the square limiting seat (16).

6. An extrusion forming method for an aluminum alloy automobile drive shaft, characterized in that, The extrusion forming equipment for an aluminum alloy automobile drive shaft described in claim 1 is adopted, and the specific steps are as follows: A. Make the opening of the heat preservation sleeve (21) face the outlet of the preheating furnace, and push the aluminum bar preheated to the plastic state into the heat preservation sleeve (21). B. Preheat the flexible jaws (20) to a temperature close to that of the aluminum bar, start the jaw component, and clamp and fix the aluminum bar. C. Transport the heat preservation component to the rotating guiding groove (10), and then drive the heat preservation component to rotate so that the opening direction of the heat preservation sleeve (21) turns vertically downward and aligns with the mold inlet. D. Control the jaw component to loosen the clamping of the aluminum bar, so that the aluminum bar falls into the mold, remove the heat preservation component, and then start the hydraulic system to drive the extrusion rod to extrude the aluminum bar to form the aluminum bar.

7. The extrusion forming method of the aluminum alloy automobile drive shaft according to claim 6, characterized in that: During the process that the aluminum bar falls into the mold, it first passes through the infrared thermometer (6). The infrared thermometer (6) scans the surface temperature of the aluminum bar in real time, identifies the abnormal area where the temperature drop is ≥20°C, and feeds the detection signal back to the control system to generate a surface temperature cloud map of the aluminum bar.

8. The extrusion forming method of the aluminum alloy automobile drive shaft according to claim 6, characterized in that: When the abnormal area of the aluminum bar temperature moves into the heating range of the annular induction heating coil, the control system triggers the annular induction heating coil to perform local heating on it.

9. The extrusion forming method of the aluminum alloy automotive drive shaft according to claim 8, wherein: Control the loosening force of the jaw component so that the residence time of the low-temperature area on the surface of the aluminum bar in the annular induction heating coil matches the heating requirement.

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