Internal and external double-effect electromagnetic induction heating system and method for tire curing bladder

Abstract

The invention discloses an internal and external double-effect electromagnetic induction heating system and method for a tire curing bladder. The system comprises an electromagnetic induction heating assembly, a Venturi circulating system, a composite flow guide cover and a controller, the electromagnetic induction heating assembly comprises an electromagnetic induction coil and a long-strip fin plate array, and vent holes are formed in the wall face of the center rod. An inlet of the venturi tube is connected with the air supply unit through an air inlet pipeline, an outlet of the venturi tube is connected with an inlet in the lower end of the center rod, and a narrow opening of the venturi tube is connected with the capsule through a circulating pipeline; the center rod is sleeved with the composite flow guide cover, and a channel is formed between the composite flow guide cover and the capsule. And the controller is connected with the electric control valve, the pressure meter, the electromagnetic power supply control unit and the temperature sensor. The fin plates and the wall face of the center rod are excited to generate heat through electromagnetic induction heating, active circulation of nitrogen is achieved in combination with the Venturi effect, the heating efficiency of the wall face of the center rod on the nitrogen is improved by optimizing a flow field, and therefore the efficient and uniform heating effect is achieved.

Description

Technical Field

[0001] This invention belongs to the field of tire vulcanization equipment technology, specifically relating to an electromagnetic induction heating system and method for tire vulcanization capsules with both internal and external effects. Background Technology

[0002] In tire manufacturing, the vulcanization process is a crucial step determining the final performance and quality of a tire. Its heating efficiency and control precision directly affect the tire's product quality and lifespan. Traditional tire vulcanization processes generally use steam or superheated water as the heating medium, achieving vulcanization through external heating of the mold. This traditional heating method has significant technical limitations, mainly manifested in low heating efficiency, uneven temperature distribution, and high energy consumption. Due to the complex three-dimensional curved surface characteristics of the tire structure, there are significant differences in thickness and heat capacity among different parts such as the tire crown, shoulder, and sidewall. When using external heating, the actual temperature distribution in each part is often uneven, easily leading to localized over-vulcanization or under-vulcanization, seriously affecting the consistency of tire product quality and performance. This problem of temperature unevenness is particularly prominent in the manufacturing process of large engineering machinery tires and high-performance passenger tires, directly restricting the improvement of product quality.

[0003] In recent years, although some technologies have attempted to introduce electromagnetic induction heating elements into vulcanizing equipment, most of these solutions have significant technical drawbacks. Most of these solutions place the heating unit outside the mold or in a separate heating device. For example, invention patent CN 104385502 B discloses an electromagnetic induction heated outer mold for tire vulcanization, consisting of an upper mold, a circumferential mold, and a lower mold. It abandons the traditional bow-shaped seat transmission, using an additional hydraulic cylinder to power the tread blocks. The upper mold, circumferential mold, and lower mold form a complete outer contour of the finished tire, ensuring that the heat transfer path from the middle mold to the tread blocks is entirely metal and follows the same path, guaranteeing consistent heat transfer and uniform heat distribution. Heating the outer mold for tire vulcanization using electromagnetic induction heating eliminates the need for steam, provides rapid heating, significantly reduces heat loss, and greatly improves thermal efficiency. Electromagnetic induction heating also enables digital temperature control of the mold, allowing for the determination of the optimal vulcanization heating process through multiple experiments. The aforementioned solutions, with the heating unit located outside the mold, result in excessively long energy transfer paths and low thermal efficiency.

[0004] Another example is the invention patent with publication number CN119820901A, which discloses a rubber tire vulcanization molding process using an electromagnetically heated gas medium. The electromagnetic heating, heat transfer medium, and its recycling are all gaseous media, particularly carbon dioxide gas. The process includes: placing a rubber tire blank within a mold cavity enclosed by a lower heating plate, an upper heating plate, and a mold sleeve; inserting a vulcanizing bladder into the rubber tire blank ring; heating the carbon dioxide gas through a gas medium heating component to form a high-temperature carbon dioxide gas medium; establishing an external temperature heating cycle (heating carbon dioxide) on the outside of the rubber tire blank and an internal temperature heating cycle on the inside of the rubber tire blank; cooling and shaping after meeting the vulcanization molding process requirements; evacuating the vulcanizing bladder, opening the mold, and removing the tire. This method, which involves heating carbon dioxide externally and then introducing the heated carbon dioxide into the tire blank, also suffers from problems such as an excessively long energy transfer path, low thermal efficiency, and difficulty in temperature control.

[0005] Furthermore, the central mechanism of existing tire vulcanizing machines generally employs a simple piston rod design, which only serves the basic functions of transmitting pressure and sealing the bladder, failing to contribute positively to thermal management during the vulcanization process. This limitation of traditional design means that the temperature distribution during vulcanization relies entirely on external heating systems and natural convection, making precise temperature control difficult.

[0006] In the tire vulcanization process, the circulation of the heat transfer medium (such as nitrogen) is also crucial. Some existing gas circulation solutions often focus only on circulation intensity, neglecting the significant impact of flow field optimization on heat exchange efficiency. Achieving efficient heat exchange while ensuring operational safety within a confined space has always been a technical challenge in the industry. Therefore, developing a tire vulcanization heating system that can simultaneously address heating efficiency, temperature uniformity, and operational safety has significant technological value and market potential. Summary of the Invention

[0007] To overcome the problems existing in the prior art, the present invention provides an electromagnetic induction heating system and method for tire vulcanizing bladder with both internal and external effects. The system simultaneously excites the internal finned plate and the outer wall of the piston rod / center rod to generate heat through electromagnetic induction heating, and achieves active circulation of nitrogen by combining the Venturi effect. By optimizing the flow field, the heating efficiency of the outer wall of the piston rod / center rod on nitrogen is improved, thereby achieving a highly efficient and uniform heating effect.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] On the one hand, the present invention provides an electromagnetic induction heating system for tire vulcanizing bladder with both internal and external effects, including an electromagnetic induction heating assembly, a Venturi circulation system, a composite deflector and a controller;

[0010] The electromagnetic induction heating assembly includes an electromagnetic induction coil disposed inside a hollow piston rod or a central rod, and an array of elongated finned plates distributed along the circumference. The piston rod or central rod wall is provided with multiple vent holes or vent slots. The electromagnetic induction coil is connected to an electromagnetic power supply control unit.

[0011] The Venturi circulation system includes a Venturi tube, the inlet of which is connected to the air supply unit through an air intake pipe, the outlet of which is connected to the lower inlet of the piston rod or center rod, and the narrow opening of the Venturi tube is connected to the capsule through a circulation pipe.

[0012] The composite flow guide is fitted over the piston rod or the center rod, and a channel is provided between the composite flow guide and the capsule;

[0013] The controller is connected to the electric regulating valve and pressure gauge on the air intake pipe, as well as the electromagnetic power supply control unit and multiple temperature sensors installed on the inner wall of the capsule.

[0014] Preferably, the composite flow guide is a cone-shaped body that is closed at the top and open at the bottom, with spiral fins provided on the inner wall of the cone, and heated gas flows into the capsule from the bottom.

[0015] Preferably, the composite flow guide is a cylinder closed at both ends, and a Laval structure micropore array is formed on the side wall of the cylinder, through which heated gas enters the capsule.

[0016] Preferably, the electromagnetic induction coil is spirally arranged from top to bottom on the inner wall of the hollow piston rod or central rod, and has a U-shaped or arc-shaped structure.

[0017] Preferably, the venturi tube has an inlet cone angle of 15-20 degrees, an outlet diffusion angle of 5-8 degrees, and a throat diameter to inlet diameter ratio of 0.45-0.55.

[0018] Preferably, the upper and lower ends of the hollow piston rod or central rod are respectively provided with a heat insulation layer and a heat insulation ring.

[0019] Preferably, the finned plate is made of copper alloy, and the heat-conducting fins of the finned plate are connected to the wall surface of the piston rod or the center rod.

[0020] On the one hand, the present invention also provides an electromagnetic induction heating method for tire vulcanizing bladders with both internal and external effects, comprising the following steps:

[0021] S1. Install the tire vulcanizing bladder and turn on the electromagnetic induction heating;

[0022] S2. The internal finned plates heat up rapidly under the action of electromagnetic induction, which preheats the low-temperature gas flowing in from the Venturi tube.

[0023] S3. The preheated gas flows through the wall of the piston rod or center rod with vent holes / vent grooves and is reheated by electromagnetic induction heat from the wall.

[0024] S4. After secondary heating, the gas enters the composite flow guide shroud. Under the action of the composite flow guide shroud, a swirling flow is generated to enhance the convective heat transfer effect, prolonging the contact time with the high-temperature piston rod / center rod and the wall of the composite flow guide shroud, achieving temperature uniformity, and increasing the outflow velocity of the gas, thereby improving the uniformity of the gas temperature inside the capsule.

[0025] S5, the Venturi circulation system drives the gas circulation inside the capsule to ensure uniform temperature distribution.

[0026] Preferably, in step S5, the gas is accelerated by the venturi tube to form a high-speed airflow, which generates a negative pressure effect at the throat of the venturi tube, and attracts the gas inside the capsule to participate in the circulation mixing through the circulation pipe.

[0027] Preferably, the gas is nitrogen or argon.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. The electromagnetic induction coil of this invention generates an alternating magnetic field, utilizing the skin effect of electromagnetic induction, and simultaneously excites the walls of the internal finned plate, piston rod, or central rod to rapidly heat up. The internal finned plate is mainly responsible for the initial heating of the low-temperature nitrogen flowing into the piston rod or central rod; the walls of the piston rod or central rod then deeply heat the nitrogen through convection and radiation heat exchange; at the same time, the composite flow guide enhances the heat exchange effect of nitrogen between the composite flow guide and the outer wall of the piston rod / central column, and combines the Venturi effect to achieve active circulation of nitrogen. By optimizing the flow field, the heating efficiency of the outer wall of the piston rod / central column on nitrogen is improved, thereby achieving progressive heating of nitrogen and ultimately achieving a highly efficient and uniform heating effect.

[0030] 2. The piston rod or center rod of the present invention serves as a carrier for electromagnetic induction heating. This design not only enables the piston rod or center rod to perform the basic functions of transmitting pressure and sealing the capsule, but also places the heat source inside the capsule, shortening the heat transfer path and facilitating precise temperature control.

[0031] 3. This invention ensures the rational distribution and effective utilization of heat by staged heating of nitrogen gas (first-stage finned plate heating, second-stage piston rod or center rod wall heating, third-stage composite flow guide shroud to enhance convective heat transfer, and fourth-stage venturi tube to drive gas circulation inside the capsule, ensuring uniform gas temperature distribution), thereby improving the thermal efficiency of the system.

[0032] 4. In this invention, due to the skin effect of electromagnetic induction and the differences in structure and thermal inertia between the internal finned plate and the external piston rod / center rod wall, the internal finned plate can achieve a higher transient temperature, while the external wall forms a slightly lower but uniformly distributed steady-state thermal field. This differentiated design allows the low-temperature nitrogen gas to be rapidly preheated by undergoing high-intensity impact heat exchange with the high-temperature finned plate, and then homogenizing and deepening the temperature on the uniform main heating wall. This process achieves efficient and controllable progressive heating, avoiding the thermal shock that may occur when cold fluid directly impacts the homogenizing wall, and optimizing the overall heat exchange efficiency through division of labor and cooperation.

[0033] 5. The upper and lower ends of the hollow piston rod or center rod are respectively provided with heat insulation layer and heat insulation ring to prevent heat transfer from the piston rod / center rod to adjacent contact structures.

[0034] 6. The outer layer of the composite flow guide is made of aluminum silicate cotton felt insulation material, which has a heat insulation effect and prevents the capsule from coming into contact with the high temperature piston rod or center rod wall when it contracts. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of one embodiment of the electromagnetic induction heating system for tire vulcanizing bladders with both internal and external effects according to the present invention.

[0036] Figure 2 This is a schematic diagram of another embodiment of the electromagnetic induction heating system for tire vulcanizing bladders with both internal and external effects according to the present invention.

[0037] Figure 3 This is a diagram of the overall system architecture.

[0038] Figure 4 A schematic diagram of a composite air deflector with a cylindrical structure;

[0039] Figure 5 This is a schematic diagram of the structure of an electromagnetic induction coil;

[0040] Figure 6 The design intent is to create a slotted structure on the annular wall of the piston rod / center rod.

[0041] Figure label:

[0042] 1. Electromagnetic induction heating assembly; 11. Electromagnetic induction coil; 12. Finned plate; 2. Venturi circulation system; 21. Venturi tube; 22. Circulation pipe; 3. Composite flow guide shroud; 31. Spiral fins; 32. Micropores; 4. Center rod; 41. Vent groove; 5. Capsule; 6. Insulation layer; 7. Insulation ring; 8. Upper chuck; 9. Lower chuck. Detailed Implementation

[0043] To make the objectives and advantages of the present invention clearer, the present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] like Figure 1 , 2 As shown, this invention is an electromagnetic induction heating system for tire vulcanizing bladders with both internal and external effects. The upper and lower ends of the bladder 5 are clamped onto an upper chuck 8 and a lower chuck 9. The center of the lower chuck 9 is mounted on the ring seat of the vulcanizing machine. The piston rod or center rod 4 passes through the center of the upper chuck 8 and the center of the ring seat. This system includes an electromagnetic induction heating assembly 1, a Venturi circulation system 2, a composite flow guide shroud 3, and a controller. The electromagnetic induction heating assembly 1 achieves internal and external dual-effect heating of nitrogen gas through the array of finned plates 12 and the wall of the external piston rod or center rod 4, and is the core component of this invention. The composite flow guide shroud 3 extends the heat exchange time of nitrogen gas, and the Venturi circulation system 2 drives the gas inside the bladder 5 to form an active circulation, thereby heating the nitrogen gas. The controller is used to monitor the temperature of the bladder 5 and achieves more precise control of the heating process by adjusting the power of the electromagnetic coil and controlling the nitrogen gas flow rate.

[0045] The electromagnetic induction heating assembly 1 includes an electromagnetic induction coil 11 disposed inside a hollow piston rod or central rod 4, and an array of elongated finned plates 12 distributed along the circumference. The finned plates 12 are multiple in number and made of high thermal conductivity materials such as copper alloy. Under electromagnetic induction, they heat up rapidly, primarily preheating the incoming low-temperature nitrogen gas. These finned plates 12 are distributed circumferentially and extend from the lower end to the upper end of the piston rod or central rod 4. The heat-conducting fins of the finned plates 12 can be connected to the wall of the piston rod or central rod 4 to form a complete heat conduction path, ensuring that heat can be effectively transferred from the inside to the outside.

[0046] like Figure 5As shown, the electromagnetic induction coil 11 is pre-formed into a U-shaped or arc-shaped structure, tightly surrounding the array of finned plates 12. The electromagnetic induction coil 11 is connected to a high-frequency power supply to generate an alternating magnetic field. This design ensures that the alternating magnetic field can simultaneously and effectively couple the inner and outer metal structures to achieve dual-effect heating. This allows the inner finned plate 12 to achieve the fastest temperature rise rate, while also enabling the piston rod or central rod 4 wall to deeply heat the nitrogen gas through convection and radiation heat exchange. The operating frequency of the electromagnetic induction coil 11 is set in the range of 1-100kHz. This frequency range ensures both sufficient penetration depth and heating efficiency. The heating process and mechanism of this invention: Due to the skin effect of electromagnetic induction and the material differences between the finned plate 12 and the piston rod or central rod 4, the inner finned plate 12 exhibits the fastest temperature rise rate, while the temperature rise of the outer piston rod or central rod 4 wall is relatively slow. This differentiated temperature rise characteristic allows the nitrogen gas to be gradually heated in a reasonable order from low temperature to high temperature, avoiding thermal shock and improving heat exchange efficiency.

[0047] This invention improves the piston rod or central rod 4 by designing it as a hollow cylindrical structure with a closed upper end and an open lower end. This cleverly utilizes the structural characteristics of the central mechanism, using its interior as a carrier for electromagnetic induction heating. Figure 6 As shown, the piston rod or center rod 4 has vent holes or vent grooves 41 evenly distributed on its wall surface. The vent grooves 41 are horizontally arranged V-shaped grooves or similar structures, used for the circulation of nitrogen. The upper and lower ends of the piston rod or center rod 4 are respectively provided with heat insulation layers 6 and heat insulation rings 7 to prevent heat transfer from the piston rod / center rod 4 to adjacent contact structures.

[0048] The Venturi circulation system 2 includes a Venturi tube 21. The inlet of the Venturi tube 21 is connected to the air supply unit via an air intake pipe, and the outlet of the Venturi tube 21 is connected to the lower inlet of the piston rod or center rod 4. The narrow opening of the Venturi tube 21 is connected to the capsule 5 via a circulation pipe 22. The Venturi tube 21 is made of high-strength heat-resistant alloy steel, with an inlet cone angle of 15-20 degrees, an outlet diffusion angle of 5-8 degrees, and a throat diameter to inlet diameter ratio of 0.45-0.55. The throat area undergoes surface nitriding treatment, achieving a hardness of HRC60 or higher, ensuring wear resistance and service life under 2.5MPa high-pressure, high-speed airflow conditions. The Venturi tube 21 and the lower chuck 9 are sealed together via a high-pressure flange to connect to the lower inlet of the piston rod or center rod 4, with a sealing rating meeting the 2.8MPa pressure requirement. To adapt to different working conditions, the Venturi circulation system 2 also includes a pressure regulating device, which can automatically adjust the operating state of the Venturi system according to actual working conditions, ensuring optimal circulation performance under various pressure conditions. The pressure regulating device includes an electrically operated regulating valve and a pressure sensor installed on the intake pipe, along with a controller.

[0049] The composite flow guide shroud 3 is fitted over the piston rod or central rod 4 and connected to the upper chuck 8 and / or lower chuck 9. The composite flow guide shroud 3 can be designed in two shapes: one is a cone-shaped body closed at the top and open at the bottom, with spiral fins 31 on the inner wall of the cone. The spiral fins 31 optimize the flow field and enhance the heat exchange effect between the composite flow guide shroud 3 and the outer wall of the piston rod / central column. The heated nitrogen flows into the capsule 5 from the bottom. Figure 4 As shown, the composite flow deflector 3 can also be a cylinder closed at both ends. The sidewalls of the cylinder are provided with an array of Laval-structured micropores 32 to enhance the internal nitrogen heat exchange effect. Heated nitrogen enters the capsule 5 through the micropore array 32. The composite flow deflector 3 uses a ceramic fiber rigid heat-insulating tile material as its outer layer to prevent the piston rod / center rod 4 from directly contacting other components.

[0050] The controller can be installed on the vulcanizing machine and mainly includes a main controller, a power control module, a flow control module connected to the main controller, an electric regulating valve on the intake pipe, a pressure detector, an electromagnetic power supply control unit, and multiple temperature sensors (forming a temperature sensor array) installed on the inner wall of capsule 5. Figure 3 As shown, the controller and temperature sensor array constitute a control and monitoring system. The temperature sensors monitor the temperature changes inside capsule 5 in real time and send the data to the controller. The main controller dynamically adjusts the output power of the electromagnetic induction coil 11 based on the real-time temperature data through the power control module. Higher power is used in the initial stage of vulcanization to achieve rapid heating, while the power is appropriately reduced during the pressure holding stage to maintain temperature stability. The main controller precisely controls the gas flow by regulating a high-precision electric regulating valve through the flow control module. The system is also equipped with advanced fault self-diagnosis functions, which can monitor the system status in real time, promptly detect abnormalities, and ensure the safe and reliable operation of the equipment.

[0051] During system operation, a high-frequency power supply powers the pre-formed electromagnetic induction coil 11 inside the piston rod / center rod 4, generating an alternating magnetic field to heat the internal finned plate 12 and the piston rod / center rod 4. Simultaneously, a nitrogen supply unit provides compressed nitrogen, which is accelerated by the venturi tube 21 to form a high-speed airflow. This creates a negative pressure effect at the venturi throat, attracting gas from inside the capsule 5 through the circulation pipe 22 for cyclic mixing. The composite flow guide shroud 3 achieves efficient heat exchange between the nitrogen and the high-temperature piston rod / center rod 4 surface. The controller collects real-time temperature data inside the capsule 5 using a temperature sensor array and dynamically adjusts the electromagnetic induction power and the flow rate of the venturi tube 21 to ensure temperature uniformity is controlled within ±1.0°C throughout the vulcanization process. The system automatically adapts to both the 0.9MPa rapid heating stage and the 2.5MPa pressure holding vulcanization stage, maintaining optimal operating conditions. This integrated system achieves efficient electromagnetic induction heating, uniform cyclic mixing via the venturi tube 21, and reliable thermal insulation, providing a new heating method for tire vulcanization processes. This invention is particularly applicable to the vulcanization process of high-performance tires and large engineering machinery tires.

[0052] This invention also provides a method for electromagnetic induction heating of tire vulcanizing bladders with both internal and external effects, comprising the following steps:

[0053] S1. Install tire vulcanizing capsule 5 and turn on electromagnetic induction heating;

[0054] S2. The internal finned plate 12 heats up rapidly under the action of electromagnetic induction, which preheats the low-temperature nitrogen gas flowing in from the venturi tube 21.

[0055] S3. The preheated nitrogen flows through the wall of the piston rod or center rod 4 with vent holes / vent grooves 41 and is heated again by the electromagnetic induction heat of the wall.

[0056] S4. The gas after secondary heating enters the composite flow guide hood 3. Under the action of the composite flow guide hood 3, a swirling enhanced convection heat transfer effect is generated, which prolongs the contact time with the high-temperature piston rod / center rod 4 and the wall of the composite flow guide hood 3, achieves temperature balance, and increases the outflow nitrogen flow rate, thereby improving the uniformity of nitrogen temperature inside the capsule.

[0057] S5. Nitrogen gas is accelerated by the venturi tube 21 to form a high-speed airflow, which generates a negative pressure effect at the throat of the venturi tube 21. The airflow then draws the gas inside the capsule 5 into the circulation and mixing through the circulation pipe 22, ensuring uniform temperature distribution.

[0058] The above embodiments are merely specific examples to further illustrate the purpose, technical solution, and beneficial effects of the present invention, and the present invention is not limited thereto. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the disclosure of the present invention are included within the protection scope of the present invention.

Claims

1. An electromagnetic induction heating system for tire vulcanizing bladders with both internal and external effects, characterized in that: It includes an electromagnetic induction heating assembly (1), a venturi circulation system (2), a composite air deflector (3), and a controller; The electromagnetic induction heating assembly (1) includes an electromagnetic induction coil (11) disposed inside the hollow piston rod or central rod (4) and an array of elongated finned plates (12) distributed along the circumference. The piston rod or central rod (4) has multiple ventilation holes or ventilation slots (41) on its wall surface. The electromagnetic induction coil (11) is connected to the electromagnetic power supply control unit. The Venturi circulation system (2) includes a Venturi tube (21), the inlet of which is connected to the air supply unit through an air intake pipe, the outlet of which is connected to the lower inlet of the piston rod or center rod (4), and the narrow opening of which is connected to the capsule (5) through a circulation pipe (22). The composite flow guide (3) is covered outside the piston rod or the center rod (4), and a channel is provided between the composite flow guide (3) and the capsule (5); The controller is connected to the electric regulating valve and pressure gauge on the air intake pipe, as well as the electromagnetic power supply control unit and multiple temperature sensors installed on the inner wall of the capsule (5).

2. The electromagnetic induction heating system for a tire vulcanizing bladder with both internal and external effects according to claim 1, characterized in that: The composite flow guide (3) is a cone-shaped body that is closed at the top and open at the bottom. Spiral fins (31) are provided on the inner wall of the cone. Heated gas flows into the capsule (5) from the bottom.

3. The electromagnetic induction heating system for tire vulcanizing bladders with both internal and external effects according to claim 1, characterized in that: The composite flow guide (3) is a cylinder with closed ends. The side wall of the cylinder is provided with a Laval structure micropore (32) array. The heated gas enters the capsule (5) through the micropore (32) array.

4. The electromagnetic induction heating system for a tire vulcanizing bladder with both internal and external effects according to claim 1, characterized in that: The electromagnetic induction coil (11) is spirally arranged from top to bottom on the inner wall of the hollow piston rod or the central rod (4), and it has a U-shaped structure or an arc-shaped structure.

5. The electromagnetic induction heating system for a tire vulcanizing bladder with both internal and external effects according to claim 1, characterized in that: The venturi tube (21) has an inlet cone angle of 15-20 degrees, an outlet diffusion angle of 5-8 degrees, and a throat diameter to inlet diameter ratio of 0.45-0.

55.

6. The electromagnetic induction heating system for a tire vulcanizing bladder with both internal and external effects according to claim 1, characterized in that: The hollow piston rod or central rod (4) is provided with a heat insulation layer (6) and a heat insulation ring (7) at its upper and lower ends, respectively.

7. The electromagnetic induction heating system for a tire vulcanizing bladder with both internal and external effects according to claim 1, characterized in that: The finned plate (12) is made of copper alloy material, and the heat-conducting fins of the finned plate (12) are connected to the wall of the piston rod or the center rod (4).

8. A method for electromagnetic induction heating of tire vulcanizing bladders with both internal and external effects, characterized in that: The electromagnetic induction heating system for the dual-effect tire vulcanizing bladder according to any one of claims 1-7, the heating method comprising the following steps: S1. Install the tire vulcanizing capsule (5) and turn on the electromagnetic induction coil (11) to heat it; S2. The internal finned plate (12) heats up rapidly under the action of electromagnetic induction, which preheats the low-temperature gas flowing in from the venturi tube (21). S3. The preheated gas flows through the wall of the piston rod or center rod (4) with vent holes / vent grooves (41) and is heated a second time by the electromagnetic induction heat of the wall. S4. After secondary heating, the gas enters the composite guide hood (3). Under the action of the composite guide hood (3), a swirling flow is generated to enhance the convective heat transfer effect, prolonging the contact time with the high-temperature piston rod / center rod (4) and the wall of the composite guide hood (3), achieving temperature balance, and increasing the outflow velocity of the gas, thereby improving the uniformity of the gas temperature inside the capsule (5). S5. The Venturi circulation system drives the gas circulation inside the capsule (5) to ensure uniform temperature distribution.

9. The method for electromagnetic induction heating of a tire vulcanizing bladder with both internal and external effects according to claim 8, characterized in that: In step S5, the gas is accelerated by the Venturi tube (21) to form a high-speed airflow, and a negative pressure effect is generated at the throat of the Venturi tube (21). The gas inside the capsule (5) is attracted to participate in the circulation mixing through the circulation pipe (22).

10. The method for electromagnetic induction heating of a tire vulcanizing bladder with both internal and external effects according to claim 8, characterized in that: The gas is nitrogen or argon.

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