Uniform foaming extrusion die for automobile engine cover

Abstract

The invention discloses an automobile engine hood uniform foaming extrusion die, which relates to the technical field of plastic molding, and comprises a die main body, a melt distribution structure and a flow adjusting device. Through the arrangement of the melt distribution structure and the flow adjusting device, a main feeding channel in the melt distribution structure is connected with the extruder through a flange type constant-temperature connector, it is ensured that melt is stably input, in the three-stage diffusion flow divider, the first-stage fan-shaped diffusion cavity primarily diffuses the melt and changes the flow direction, and the second-stage fan-shaped diffusion cavity primarily diffuses the melt and changes the flow direction; the second-stage flow guide fins guide melt to flow and adjust flow distribution, the third-stage corrugated flow channels increase the melt flow path and the contact area, the arc-shaped transition faces between the stages reduce the flow resistance and reduce the turbulence intensity, melt distribution is more uniform, and the flow distribution efficiency is improved. The PID control module dynamically adjusts the power of the spiral heating pipe and the flow speed of cooling liquid of the spiral cooling pipe according to the real-time temperature data, and precise control over the temperature of the forming cavity is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic molding, and particularly to a uniform foaming extrusion die for an automobile engine hood. Background Art

[0002] Driven by the demands of automotive lightweighting and energy conservation, plastic engine hoods have gradually become the mainstream solution due to their large molding freedom and significant weight reduction effect. An injection molding can be performed on a foaming extrusion die, and the foaming extrusion die realizes the balance between lightweighting and performance by controlling the bubble nucleation, expansion, and curing processes in the plastic melt.

[0003] The defects existing in the existing foaming extrusion dies are as follows: 1. Patent document US4797083A discloses an extrusion die for manufacturing foamed thermoplastic webs. However, during the use of the device in the above document, when transporting and extruding the melt, there is a technical problem that the distribution is uneven, resulting in poor movement effect of the melt; 2. Patent document US06383425B1 discloses a method for extruding a foamed polypropylene sheet with improved surface appearance. However, the device in the above document has a technical problem that it cannot flexibly adjust the extrusion direction according to the requirements of different products; 3. Patent document US20150048535A1 discloses a method and device for cooling foamed polymeric materials. However, during the use of the device in the above document, there is a technical problem that the service life of the flow channel is short; 4. Patent document CN104385554A discloses a PVC foamed board extrusion die. However, the device in the above document has technical problems of poor flexibility and easy leakage. Summary of the Invention

[0004] The purpose of the present invention is to provide a uniform foaming extrusion die for an automobile engine hood to solve the technical problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A uniform foaming extrusion die for an automobile engine hood, including a die body, a melt distribution structure, and a flow regulation device. The melt distribution structure and the flow regulation device are arranged inside the die body. The die body includes an upper die and a lower die. An installation groove is provided at the front end of the top of the lower die, and the inner wall of the installation groove is movably connected to the upper die. A molding cavity matching the contour of the automobile engine hood is provided between the lower die and the upper die; The melt distribution structure includes a main feed channel, a three-stage diffusion diverter, and a gradient temperature control unit. The main feed channel is arranged in the middle of the back of the lower mold. The input end of the main feed channel is connected with a flange-type constant temperature interface by bolts, and the other end of the flange-type constant temperature interface is connected with the input end of an extruder by bolts; The three-stage diffusion diverter includes a first-stage fan-shaped diffusion cavity, a second-stage guiding fin, and a third-stage corrugated flow channel. Arc-shaped transition surfaces are provided between the first-stage fan-shaped diffusion cavity and the second-stage guiding fin and between the second-stage guiding fin and the third-stage corrugated flow channel. The first-stage fan-shaped diffusion cavity is used for initially diffusing the melt and changing the flow direction. The second-stage guiding fin is used for guiding the melt flow and regulating the flow rate distribution. The third-stage corrugated flow channel is used for increasing the melt flow path and contact area. The arc-shaped transition surface is used for reducing the flow resistance and decreasing the turbulence intensity; The gradient temperature control unit is alternately provided with spiral heating pipes and spiral cooling pipes along the circumference of the forming cavity. The gradient temperature control unit includes an embedded thermocouple array and a PID control module. The embedded thermocouple array is used for arranging 3-5 groups of temperature measurement points longitudinally along the forming cavity. The PID control module is used for dynamically adjusting the power of the spiral heating pipes and the coolant flow rate of the spiral cooling pipes according to the real-time temperature data.

[0006] Preferably, the flow regulating device includes a multi-stage pressure buffer and an adjustable extrusion terminal. The multi-stage pressure buffer is arranged inside the main feed channel. The multi-stage pressure buffer is composed of alternately connected tapered sections and expanded sections. A turbulence suppression ring is arranged at the connection of the tapered section and the expanded section. The inner wall of the turbulence suppression ring is provided with an annular groove with a depth of 0.2-0.4 mm, and a porous ceramic damping sheet is fitted and installed inside the annular groove; The adjustable extrusion terminal is arranged at the output end of the three-stage diffusion diverter. The output end of the adjustable extrusion terminal is provided with 8 extrusion heads with independent angle adjustment mechanisms, and each extrusion head is equipped with a ball hinge adjustment mechanism and a pressure compensation ring. 8 pressure equalizing holes are arranged inside the pressure compensation ring.

[0007] Preferably, for the first-stage fan-shaped diffusion cavity, its inlet is communicated with the outlet of the main feed channel, and the diffusion angle is 90-120°; The second-stage guiding fin is composed of fins distributed radially, and the distance between each fin decreases by 5-15% from the center to the edge; For the third-stage corrugated flow channel, the surface corrugation amplitude is 1-3 mm and the wavelength is 5-8 mm, forming a serpentine flow path; The transition curvature radius R of the arc-shaped transition surface is 1.2-1.5 times the height of the cavity.

[0008] Preferably, a nano-scale liquid-repellent coating is provided on the inner wall of the third-stage corrugated flow channel. The nano-scale liquid-repellent coating is used to improve the service life of the flow channel wall and prevent damage caused by the erosion of the melt.

[0009] Preferably, the porosity of the porous ceramic damping sheet is 45-65%, the pore size is 0.05-0.25 mm, and a honeycomb support skeleton is embedded therein. The honeycomb support skeleton is made of silicon carbide material, and its wall thickness is 20-33% of the pore diameter, forming a hierarchical filtration structure.

[0010] Preferably, a double-channel sealing structure is provided at the joint surface of the upper mold and the lower mold, including a metal labyrinth sealing ring on the outside and a silicon nitride ceramic sealing strip on the inside. The metal labyrinth sealing ring is provided with 3 layers of staggered sawtooth structures, and the distance between adjacent sawteeth is 0.8-1.2 mm, forming a non-contact dynamic seal; A connecting mechanism is provided at the top of the upper mold for connecting the lifting device.

[0011] Preferably, the ball hinge adjustment mechanism is integrated with a micro servo motor and an angle encoder. The micro servo motor drives the extrusion head to perform three-dimensional angle fine adjustment within the range of ±15° through a worm and gear transmission mechanism, and the angle resolution reaches 0.1°. The angle encoder and the PID control module form a closed-loop feedback system.

[0012] Preferably, an ejection mechanism is provided at the bottom of the molding cavity. The ejection mechanism includes a hydraulic cylinder, and the outer wall of the hydraulic cylinder is fitted and installed inside the lower mold. An installation chamber is provided on the inner bottom wall of the molding cavity, and the inner wall of the installation chamber is installed on the outer wall of the hydraulic cylinder.

[0013] Preferably, the working steps of the uniform foaming extrusion mold for the automotive engine hood are as follows: S1. Inject the molten foaming material into the main feed channel through the flange-type constant temperature interface by an extruder; S2. The embedded thermocouple array monitors the temperature in real time at 3-5 temperature measurement points longitudinally distributed along the molding cavity. The PID control module dynamically adjusts the power of the spiral heating tube and the coolant flow rate of the spiral cooling tube according to the temperature data, and establishes an alternating heating or cooling gradient field along the circumferential direction of the molding cavity to ensure the melt fluidity and foaming uniformity; S3. First-stage diffusion: The melt enters the first-stage fan-shaped diffusion cavity, is preliminarily diffused and changes the flow direction to form a uniform basic flow field; Second-stage diversion: Guide the melt to flow in a specific direction through the second-stage diversion fins, and adjust the flow rate distribution to different regions; Third-stage path enhancement: The melt enters the third-stage corrugated flow channel, extends the flow path and increases the contact area to promote the uniform dispersion of the foaming agent; S4. The multi-stage pressure buffer in the main feed channel balances the pressure fluctuations through alternating tapered sections and expanded sections. Meanwhile, a 0.2 - 0.4 mm annular groove is provided on the inner wall of the turbulence suppression ring, and the porous ceramic damping sheet fitted in the groove further absorbs the turbulence energy to stabilize the melt flow state. S5. The eight extrusion heads of the adjustable extrusion terminal are finely adjusted in three-dimensional angles through a ball hinge adjustment mechanism, which is realized by driving a worm and worm gear transmission mechanism with a micro servo motor. And the angle encoder and the PID control module form a closed-loop feedback to adjust the extrusion direction in real time to match the complex contour of the engine hood. S6. The upper mold and the lower mold are accurately clamped through the installation grooves to form a molding cavity matching the contour of the engine hood. The melt is uniformly foamed under the synergistic action of temperature gradient, flow optimization, and pressure compensation. The temperature, pressure, and extrusion head angle parameters are monitored in real time and dynamically adjusted through the PID control module to ensure the foaming density and dimensional accuracy.

[0014] Preferably, the following steps are further included in the S3: S31. Transition optimization: The arc transition surface between the two-stage structures reduces the turbulence intensity and flow resistance. The following steps are further included in the S5: S51. Each extrusion head is equipped with a pressure compensation ring, and eight equalizing holes inside balance the local pressure to ensure uniform filling of the molding cavity with the melt.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. Through the setting of the melt distribution structure and the flow regulation device, in the melt distribution structure, the main feed channel is connected to the extruder through a flange-type constant temperature interface to ensure stable input of the melt. In the three-stage diffusion shunt, in the first-stage fan-shaped diffusion cavity, the melt is initially diffused and the flow direction is changed. In the second-stage guide fins, the melt flow is guided and the flow rate distribution is adjusted. In the third-stage corrugated flow channel, the melt flow path and contact area are increased. And the arc transition surfaces between the stages reduce the flow resistance and turbulence intensity, making the melt distribution more uniform. Then, through the setting of the spiral heating tube and the spiral cooling tube, multiple temperature measurement points are arranged longitudinally along the molding cavity by the embedded thermocouple array. The PID control module dynamically adjusts the power of the spiral heating tube and the coolant flow rate of the spiral cooling tube according to the real-time temperature data, realizing precise control of the temperature of the molding cavity. 2. Through the alternately connected tapered sections and tapered expansion sections, the present invention can ensure that the melt undergoes multiple changes in pressure and velocity during the flow process, thereby achieving the effect of evenly distributing the melt pressure and flow rate. The setting of the turbulence suppression ring can reduce the fluctuation of the melt flow and make the melt flow more smoothly. Furthermore, the output end of the adjustable extrusion terminal is provided with 8 extrusion heads with independent angle adjustment mechanisms, and each extrusion head is equipped with a spherical hinge adjustment mechanism and a pressure compensation ring. The spherical hinge adjustment mechanism can achieve multi-angle adjustment of the extrusion head in three-dimensional space and can flexibly adjust the extrusion direction according to the requirements of different products. The 8 pressure equalizing holes in the pressure compensation ring can, when the extrusion head is under different pressures, keep the melt pressure output by the extrusion head uniform through the pressure equalizing effect, thereby avoiding problems such as inconsistent thickness and uneven density of the extruded product caused by uneven pressure, and achieving the effect of improving the quality and stability of the extruded product; 3. Through the design of the first-stage fan-shaped diffusion cavity, the present invention can enable the melt to quickly diffuse after entering the diffusion cavity and initially change the flow direction. The multiple tapered fins of the second-stage guide fins can guide the melt flow, and the decreasing design of the spacing helps to adjust the flow rate distribution, enabling the melt to be reasonably distributed at different positions. The serpentine flow path formed by the third-stage corrugated flow channel increases the flow path and contact area of the melt, which is conducive to the full mixing and uniform heat dissipation of the melt. The arc transition surface can effectively reduce the flow resistance and lower the turbulence intensity, making the melt flow more smoothly. In addition, the nano-scale liquid-repellent coating provided on the inner wall of the third-stage corrugated flow channel is conducive to improving the service life of the flow channel, thereby reducing problems such as melt leakage and product quality caused by flow channel damage, and ensuring the long-term stable operation of the melt distribution structure and the quality of the extruded product; 4. Through the double-channel sealing structure at the joint surface of the upper die and the lower die, the outer metal labyrinth sealing ring has 3 layers arranged in a staggered manner, and the adjacent sawtooth spacing is 0.8 - 1.2 mm, which can form a non-contact dynamic seal to achieve the effect of blocking melt leakage. The inner silicon nitride ceramic sealing strip is conducive to further enhancing the sealing effect. The spherical hinge adjustment mechanism integrates a micro servo motor and an angle encoder. The micro servo motor drives the extrusion head to perform three-dimensional angle fine adjustment within the range of ±15° through a worm and gear transmission mechanism to achieve high-precision angle adjustment. The angle encoder and the PID control module form a closed-loop feedback system, which can real-time feedback the angle information of the extrusion head, thereby meeting the extrusion angle requirements of different products and improving the forming accuracy and consistency of the products. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a three-dimensional schematic diagram of the overall structure of the present invention; Figure 2 is a top cross-sectional schematic diagram of the overall structure of the present invention; Figure 3 of the present invention Figure 2Schematic diagram of the structure at position A in [the device]; Figure 4 For the present invention Figure 2 Schematic diagram of the structure at position B in [the device]; Figure 5 Schematic diagram of the installation groove structure of the present invention; Figure 6 For the present invention Figure 5 Schematic diagram of the structure at position C in [the device]; Figure 7 Schematic diagram of the nanoscale liquid-repellent coating structure of the present invention; Figure 8 Schematic diagram of the system flow of the present invention; Figure 9 Schematic diagram of the working process of the present invention.

[0017] In the figure: 1, die body; 2, melt distribution structure; 3, flow regulating device; 4, upper die; 5, lower die; 6, installation groove; 8, forming cavity; 9, main feed channel; 10, three-stage diffusion shunt; 11, gradient temperature control unit; 13, first-stage fan-shaped diffusion cavity; 14, second-stage guide fins; 15, third-stage corrugated flow channel; 16, arc transition surface; 17, spiral heating tube; 18, embedded thermocouple array; 19, PID control module; 20, multi-stage pressure buffer; 21, adjustable extrusion terminal; 22, tapered section; 23, expanded section; 24, turbulence suppression ring; 25, annular groove; 26, porous ceramic damping plate; 27, extrusion head; 28, spherical hinge adjustment mechanism; 29, pressure compensation ring; 30, pressure equalizing hole; 31, nanoscale liquid-repellent coating; 34, metal labyrinth seal ring; 35, silicon nitride ceramic sealing strip; 37, micro servo motor; 38, angle encoder; 39, worm and worm gear drive mechanism; 41, hydraulic cylinder; 42, spiral cooling tube; 43, installation chamber; 44, flange type constant temperature interface. Detailed implementation manners

[0018] 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 of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] Example 1: Please refer to Figure 1 , Figure 2 , Figure 7 and Figure 8 , an embodiment provided by the present invention: an evenly foamed extrusion die for an automobile engine hood, including a die body 1, a melt distribution structure 2 and a flow regulating device 3. The melt distribution structure 2 and the flow regulating device 3 are arranged inside the die body 1. The die body 1 includes an upper die 4 and a lower die 5. An installation groove 6 is arranged at the front end of the top of the lower die 5. The inner wall of the installation groove 6 is movably connected with the upper die 4. A molding cavity 8 matching the contour of the automobile engine hood is arranged between the lower die 5 and the upper die 4; The melt distribution structure 2 includes a main feed channel 9, a three-stage diffusion shunt 10 and a gradient temperature control unit 11. The main feed channel 9 is arranged in the middle of the back of the lower die 5. The input end of the main feed channel 9 is bolted with a flange type constant temperature interface 44, and the other end of the flange type constant temperature interface 44 is bolted with the input end of an extruder; The three-stage diffusion shunt 10 includes a first-stage fan-shaped diffusion cavity 13, a second-stage guide fin 14 and a third-stage corrugated flow channel 15. Arc-shaped transition surfaces 16 are arranged between the first-stage fan-shaped diffusion cavity 13 and the second-stage guide fin 14 and between the second-stage guide fin 14 and the third-stage corrugated flow channel 15. The first-stage fan-shaped diffusion cavity 13 is used for initially diffusing the melt and changing the flow direction. The second-stage guide fin 14 is used for guiding the melt flow and regulating the flow distribution. The third-stage corrugated flow channel 15 is used for increasing the melt flow path and contact area. The arc-shaped transition surface 16 is used for reducing the flow resistance and reducing the turbulence intensity; The gradient temperature control unit 11 is alternately provided with spiral heating tubes 17 and spiral cooling tubes 42 along the circumferential direction of the molding cavity 8. The gradient temperature control unit 11 includes an embedded thermocouple array 18 and a PID control module 19. The embedded thermocouple array 18 is used to arrange 3-5 groups of temperature measurement points longitudinally along the molding cavity 8. The PID control module 19 is used to dynamically adjust the power of the spiral heating tube 17 and the coolant flow rate of the spiral cooling tube 42 according to the real-time temperature data; Furthermore, through the settings of the melt distribution structure 2 and the flow regulating device 3, the main feed channel 9 in the melt distribution structure 2 is connected to the extruder through a flange-type constant temperature interface 44 to ensure stable melt input. In the three-stage diffusion diverter 10, the first-stage fan-shaped diffusion cavity 13 initially diffuses the melt and changes the flow direction. The second-stage guide fins 14 guide the melt flow and regulate the flow rate distribution. The third-stage corrugated flow channel 15 increases the melt flow path and contact area, and the arc transition surfaces 16 between each stage reduce the flow resistance and lower the turbulence intensity, making the melt distribution more uniform. Then, through the settings of the spiral heating tube 17 and the spiral cooling tube 42, the embedded thermocouple array 18 arranges multiple groups of temperature measurement points longitudinally along the molding cavity 8. The PID control module 19 dynamically adjusts the power of the spiral heating tube 17 and the coolant flow rate of the spiral cooling tube according to the real-time temperature data, realizing precise control of the temperature of the molding cavity 8.

[0022] Example 2: Please refer to Figure 2 and Figure 4 , an embodiment provided by the present invention: The flow regulating device 3 includes a multi-stage pressure buffer 20 and an adjustable extrusion terminal 21. The multi-stage pressure buffer 20 is arranged inside the main feed channel 9. The multi-stage pressure buffer 20 is composed of alternately connected tapered sections 22 and expanded sections 23. A turbulence suppression ring 24 is arranged at the connection of the tapered section 22 and the expanded section 23. The inner wall of the turbulence suppression ring 24 is provided with an annular groove 25 with a depth of 0.2-0.4 mm. A porous ceramic damping sheet 26 is fitted and installed inside the annular groove 25; The adjustable extrusion terminal 21 is arranged at the output end of the three-stage diffusion diverter 10. The output end of the adjustable extrusion terminal 21 is provided with 8 extrusion heads 27 with independent angle adjustment mechanisms, and each extrusion head 27 is equipped with a ball hinge adjustment mechanism 28 and a pressure compensation ring 29. 8 pressure equalizing holes 30 are arranged inside the pressure compensation ring 29; The porosity of the porous ceramic damping sheet 26 is 45-65%, the pore size is 0.05-0.25 mm, and a honeycomb support skeleton is embedded inside it. The honeycomb support skeleton is made of silicon carbide material, and its wall thickness is 20-33% of the pore diameter, forming a hierarchical filtration structure; Furthermore, through the alternately connected tapered sections 22 and expanded sections 23, it is possible to ensure that the melt undergoes multiple changes in pressure and velocity during the flow process, thereby achieving the effect of evenly distributing the melt pressure and flow rate. The setting of the turbulence suppression ring 24 can reduce the fluctuations in the melt flow and make the melt flow more stable. Additionally, at the output end of the adjustable extrusion terminal 21, there are 8 extrusion heads 27 equipped with independent angle adjustment mechanisms. Each extrusion head 27 is equipped with a spherical hinge adjustment mechanism 28 and a pressure compensation ring 29. The spherical hinge adjustment mechanism 28 can achieve multi-angle adjustment of the extrusion head 27 in three-dimensional space and can flexibly adjust the extrusion direction according to the requirements of different products. The 8 pressure equalizing holes 30 in the pressure compensation ring 29 can keep the melt pressure output by the extrusion head 27 uniform through pressure equalization when the extrusion head 27 is under different pressures, thereby avoiding problems such as inconsistent thickness and uneven density of the extruded product caused by uneven pressure and achieving the effect of improving the quality and stability of the extruded product. The turbulence suppression ring 24, with an annular groove 25 with a depth of 0.2 - 0.4 mm provided on its inner wall and a porous ceramic damping sheet 26 fitted in the annular groove 25, can effectively reduce the turbulence intensity of the melt flow through the porous ceramic damping sheet 26.

[0023] Example 3: Please refer to Figure 2 and Figure 7 , an embodiment provided by the present invention: The first-stage fan-shaped diffusion cavity 13, whose inlet is connected to the outlet of the main feed channel 9, has a diffusion angle of 90 - 120°; The second-stage guide fins 14 are composed of fins distributed radially, and the spacing between the fins decreases by 5 - 15% from the center to the edge; The third-stage corrugated flow channel 15, with a surface corrugation amplitude of 1 - 3 mm and a wavelength of 5 - 8 mm, forms a serpentine flow path; The transition curvature radius R of the arc transition surface 16 is 1.2 - 1.5 times the height of the cavity; The inner wall of the third-stage corrugated flow channel 15 is provided with a nano-scale liquid-repellent coating 31, and the nano-scale liquid-repellent coating 31 is used to improve the service life of the flow channel wall and prevent damage caused by the erosion of the melt; Furthermore, the design of the first-stage fan-shaped diffusion cavity enables the melt to quickly diffuse after entering the cavity, initially changing the flow direction. The multiple tapered fins of the second-stage guide fins 14 can guide the flow of the melt, and the decreasing design of the spacing helps to adjust the flow rate distribution, enabling the melt to be reasonably distributed at different positions. The serpentine flow path formed by the third-stage corrugated flow channel 15 increases the flow path and contact area of the melt, facilitating full mixing and uniform heat dissipation of the melt. The arc transition surface 16 can effectively reduce the flow resistance and lower the turbulence intensity, making the melt flow more smoothly. In addition, the nano-scale liquid-repellent coating 31 provided on the inner wall of the third-stage corrugated flow channel 15 is beneficial to improving the service life of the flow channel, thereby reducing the problems of melt leakage and product quality caused by flow channel damage, and ensuring the long-term stable operation of the melt distribution structure 2 and the quality of the extruded products.

[0024] Example 4: Please refer to Figure 2 、 Figure 3 、 Figure 5 and Figure 6 For an embodiment provided by the present invention, a double-channel sealing structure is provided at the joint surface between the upper mold 4 and the lower mold 5, including a metal labyrinth seal ring 34 on the outside and a silicon nitride ceramic sealing strip 35 on the inside. The metal labyrinth seal ring 34 is provided with 3 layers of staggered sawtooth structures, and the adjacent sawtooth spacing is 0.8 - 1.2 mm, forming a non-contact dynamic seal. The ball-hinged adjustment mechanism 28 is integrated with a micro servo motor 37 and an angle encoder 38. The micro servo motor 37 drives the extrusion head 27 to perform three-dimensional angle fine adjustment within the range of ±15° through a worm and gear transmission mechanism 39, with an angle resolution of 0.1°. The angle encoder 38 and the PID control module 19 form a closed-loop feedback system. A ejection mechanism is provided at the bottom of the molding cavity 8. The ejection mechanism includes a hydraulic cylinder 41, and the outer wall of the hydraulic cylinder 41 is fitted and installed inside the lower mold 5. An installation chamber 43 is provided on the inner bottom wall of the molding cavity 8, and the inner wall of the installation chamber 43 is installed on the outer wall of the hydraulic cylinder 41. Furthermore, through the double-channel sealing structure at the joint surface between the upper mold 4 and the lower mold 5, the outer metal labyrinth seal ring 34 is provided with 3 layers of staggered arrangements, and the adjacent sawtooth spacing is 0.8 - 1.2 mm, which can form a non-contact dynamic seal, achieving the effect of blocking the leakage of the melt. The inner silicon nitride ceramic sealing strip 35 is beneficial to further enhancing the sealing effect. The ball-hinged adjustment mechanism 28 is integrated with a micro servo motor 37 and an angle encoder 38. The micro servo motor 37 drives the extrusion head 27 to perform three-dimensional angle fine adjustment within the range of ±15° through a worm and gear transmission mechanism 39, realizing high-precision angle adjustment. The angle encoder 38 and the PID control module 19 form a closed-loop feedback system, which can real-time feedback the angle information of the extrusion head 27, thereby meeting the extrusion angle requirements of different products and improving the molding accuracy and consistency of the products. An ejection mechanism is provided at the bottom of the molding cavity 8 for ejecting the processed material.

[0025] Example 5: Please refer to Figure 9 , an embodiment provided by the present invention: The working steps of the uniform foaming extrusion die for the automobile engine hood are as follows: S1. The molten foaming material is injected into the main feed channel 9 through the flange-type constant temperature interface 44 by an extruder; S2. The embedded thermocouple array 18 monitors the temperature in real time at 3-5 temperature measurement points longitudinally distributed along the molding cavity 8. The PID control module 19 dynamically adjusts the power of the spiral heating tube 17 and the coolant flow rate of the spiral cooling tube 42 according to the temperature data, and establishes an alternating heating or cooling gradient field along the circumferential direction of the molding cavity 8 to ensure the melt fluidity and foaming uniformity; S3. First-stage diffusion: The melt enters the first-stage fan-shaped diffusion cavity 13, is preliminarily diffused and changes the flow direction to form a uniform basic flow field; Second-stage diversion: The melt is guided to flow in a specific direction through the second-stage diversion fins 14 to adjust the flow rate distribution to different regions; Third-stage path enhancement: The melt enters the third-stage corrugated flow channel 15, extends the flow path and increases the contact area to promote the uniform dispersion of the foaming agent; S4. The multi-stage pressure buffer 20 in the main feed channel 9 balances the pressure fluctuations through the alternating tapered sections 22 and expanded sections 23. At the same time, a 0.2-0.4 mm annular groove 25 is provided on the inner wall of the turbulence suppression ring 24, and the porous ceramic damping sheet 26 fitted in the groove further absorbs the turbulence energy to stabilize the melt flow state; S5. The eight extrusion heads 27 of the adjustable extrusion terminal 21 are finely adjusted in three-dimensional angles through the ball hinge adjustment mechanism 28, which is realized by driving the worm and gear transmission mechanism 39 by a micro servo motor 37. And the angle encoder 38 and the PID control module 19 form a closed-loop feedback to adjust the extrusion direction in real time to match the complex contour of the engine hood; S6. The upper mold 4 and the lower mold 5 are accurately clamped through the installation groove 6 to form a molding cavity 8 matching the contour of the engine hood. The melt is uniformly foamed under the synergistic action of the temperature gradient, flow optimization and pressure compensation. The temperature, pressure and the angle parameters of the extrusion head 27 are monitored in real time and dynamically adjusted through the PID control module 19 to ensure the foaming density and dimensional accuracy.

[0026] In S3, the following steps are further included: S31. Transition optimization: The arc transition surface 16 between the two-stage structures reduces the turbulence intensity and the flow resistance; In S5, the following steps are further included: S51. Each extrusion head 27 is equipped with a pressure compensation ring 29, and 8 internal pressure equalizing holes 30 balance the local pressure to ensure uniform filling of the melt into the molding cavity 8; In S6, the following steps are further included: S61. The 3-layer staggered serrated structure of the metal labyrinth seal ring 34 has a spacing of 0.8 - 1.2 mm to form a non-contact dynamic seal to prevent melt leakage. The silicon nitride ceramic sealing strip 35 provides high-temperature tolerance to ensure complete sealing of the molding cavity 8.

[0027] Working principle: Through the setting of the melt distribution structure 2 and the flow regulating device 3, the main feed channel 9 in the melt distribution structure 2 is connected to the extruder through the flange-type constant temperature interface 44 to ensure stable melt input. In the three-stage diffusion diverter 10, the first-stage fan-shaped diffusion cavity 13 initially diffuses the melt and changes the flow direction. The second-stage guide fins 14 guide the melt flow and regulate the flow distribution. The third-stage corrugated flow channel 15 increases the melt flow path and contact area, and the arc transition surfaces 16 between each stage reduce the flow resistance and lower the turbulence intensity, making the melt distribution more uniform. Then, through the setting of the spiral heating tube 17 and the spiral cooling tube 42, the embedded thermocouple array 18 arranges multiple temperature measurement points longitudinally along the forming cavity 8. The PID control module 19 dynamically adjusts the power of the spiral heating tube 17 and the coolant flow rate of the spiral cooling tube 42 according to the real-time temperature data, realizing precise control of the temperature of the forming cavity 8. Through the alternately connected tapered sections 22 and expanded sections 23, it can ensure that the melt experiences multiple changes in pressure and velocity during the flow process, thereby achieving the effect of evenly distributing the melt pressure and flow rate. The setting of the turbulence suppression ring 24 can reduce the fluctuation of the melt flow and make the melt flow more stable. Then, through the 8 extrusion heads 27 with independent angle adjustment mechanisms arranged at the output end of the adjustable extrusion terminal 21, and each extrusion head 27 is equipped with a spherical hinge adjustment mechanism 28 and a pressure compensation ring 29. The spherical hinge adjustment mechanism 28 can realize multi-angle adjustment of the extrusion head 27 in three-dimensional space and can flexibly adjust the extrusion direction according to the requirements of different products. The 8 pressure equalizing holes 30 in the pressure compensation ring 29 can, when the extrusion head 27 is under different pressures, keep the melt pressure output by the extrusion head 27 uniform through the pressure equalizing effect, thereby avoiding problems such as inconsistent thickness and uneven density of the extruded product caused by uneven pressure and achieving the effect of improving the quality and stability of the extruded product. The turbulence suppression ring 24, the depth of the inner wall setting is 0.2 - 0.The annular groove 25 with a diameter of 4 mm and the porous ceramic damping sheet 26 fitted inside the annular groove 25 can effectively reduce the turbulence intensity during the melt flow. Through the design of the first-stage fan-shaped diffusion cavity 13, the melt can quickly diffuse after entering the diffusion cavity and initially change the flow direction. The multiple tapered fins of the second-stage guide fins 14 can guide the melt flow, and the decreasing design of the spacing helps to adjust the flow rate distribution, enabling the melt to be reasonably distributed at different positions. The serpentine flow path formed by the third-stage corrugated flow channel 15 increases the melt flow path and contact area, which is beneficial to the full mixing and uniform heat dissipation of the melt. The arc transition surface 16 can effectively reduce the flow resistance and turbulence intensity, making the melt flow more smoothly. In addition, the nano-scale liquid-repellent coating 31 provided on the inner wall of the third-stage corrugated flow channel 15 is beneficial to improving the service life of the flow channel, thereby reducing the problems of melt leakage and product quality caused by the damage of the flow channel, ensuring the long-term stable operation of the melt distribution structure 2 and the quality of the extruded products. Through the double-channel sealing structure at the joint surface of the upper die 4 and the lower die 5, the outer metal labyrinth seal ring 34 has three layers arranged in a staggered manner, and the adjacent sawtooth spacing is 0.8 - 1.2 mm, which can form a non-contact dynamic seal to achieve the effect of blocking the melt leakage. The inner silicon nitride ceramic sealing strip 35 is beneficial to further enhancing the sealing effect. The ball hinge adjustment mechanism 28 integrates a micro servo motor 37 and an angle encoder 38. The micro servo motor 37 drives the extrusion head 27 to perform three-dimensional angle fine-tuning within the range of ±15° through the worm and gear transmission mechanism 39 to achieve high-precision angle adjustment. The angle encoder 38 and the PID control module 19 form a closed-loop feedback system, which can real-time feedback the angle information of the extrusion head 27, thereby meeting the extrusion angle requirements of different products and improving the forming accuracy and consistency of the products.

[0028] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed invention.

Claims

1. A uniform foaming extrusion die for an automobile engine cover, comprising a die body (1), a melt distribution structure (2) and a flow regulating device (3), characterized in that: The mold body (1) is provided with a melt distribution structure (2) and a flow regulating device (3) inside. The mold body (1) comprises an upper mold (4) and a lower mold (5). The front end of the top of the lower mold (5) is provided with a mounting groove (6). The inner wall of the mounting groove (6) is movably connected to the upper mold (4). A molding cavity (8) matching the contour of the automobile engine cover is provided between the lower mold (5) and the upper mold (4). The melt distribution structure (2) comprises a main feed channel (9), a three-stage diffusion splitter (10) and a gradient temperature control unit (11), and the main feed channel (9) is arranged in the middle of the back side of the lower mold (5), the input end of the main feed channel (9) is connected to a flange-type constant temperature interface (44) by bolts, and the other end of the flange-type constant temperature interface (44) is connected to the input end of the extruder by bolts; The three-stage diffuser (10) comprises a first-stage fan-shaped diffuser cavity (13), a second-stage guide fin (14) and a third-stage corrugated flow channel (15), and an arc-shaped transition surface (16) is provided between the first-stage fan-shaped diffuser cavity (13) and the second-stage guide fin (14) and between the second-stage guide fin (14) and the third-stage corrugated flow channel (15), the first-stage fan-shaped diffuser cavity (13) is used for preliminarily diffusing the melt and changing the flow direction, the second-stage guide fin (14) is used for guiding the melt flow and adjusting the flow distribution, the third-stage corrugated flow channel (15) is used for increasing the melt flow path and contact area, and the arc-shaped transition surface (16) is used for reducing the flow resistance and lowering the turbulence intensity; The gradient temperature control unit (11) is provided with spiral heating tubes (17) and spiral cooling tubes (42) alternately arranged along the circumference of the molding cavity (8). The gradient temperature control unit (11) comprises an embedded thermocouple array (18) and a PID control module (19). The embedded thermocouple array (18) is used to arrange 3 to 5 groups of temperature measurement points along the longitudinal direction of the molding cavity (8). The PID control module (19) is used to dynamically adjust the power of the spiral heating tube (17) and the coolant flow rate of the spiral cooling tube (42) according to real-time temperature data.

2. The uniform foaming extrusion die for an automobile engine cover according to claim 1, characterized in that: The flow regulating device (3) comprises a multi-stage pressure buffer (20) and an adjustable extrusion terminal (21), and the multi-stage pressure buffer (20) is arranged inside the main feed channel (9), the multi-stage pressure buffer (20) is composed of alternately connected tapered sections (22) and gradually expanding sections (23), a turbulence suppression ring (24) is arranged at the connection between the tapered sections (22) and the gradually expanding sections (23), the inner wall of the turbulence suppression ring (24) is provided with an annular groove (25) with a depth of 0.2-0.4 mm, and a porous ceramic damping plate (26) is installed in the annular groove (25); The adjustable extrusion terminal (21) is arranged at the output end of the three-stage diffuser (10), and the output end of the adjustable extrusion terminal (21) is provided with eight extrusion heads (27) with independent angle adjustment mechanisms, and each extrusion head (27) is equipped with a ball hinge adjustment mechanism (28) and a pressure compensation ring (29), and eight pressure equalization holes (30) are arranged in the pressure compensation ring (29).

3. The uniform foaming extrusion die for an automobile engine cover according to claim 1, characterized in that: The first-stage fan-shaped diffusion chamber (13) has an inlet connected to the outlet of the main feed channel (9) and a diffusion cross-angle of 90-120°; The second-stage guide fins (14) are composed of fins distributed in the radial direction, and the spacing between the fins decreases by 5-15% from the center to the edge; The third-stage corrugated flow channel (15) has a surface corrugation amplitude of 1-3 mm and a wavelength of 5-8 mm, forming a serpentine flow path; The transition curvature radius R of the arc-shaped transition surface (16) is 1.2-1.5 times the height of the cavity.

4. The uniform foaming extrusion die for an automobile engine cover according to claim 1, characterized in that: The inner wall of the third-stage corrugated flow channel (15) is provided with a nano-scale lyophobic coating (31), and the nano-scale lyophobic coating (31) is used to increase the service life of the flow channel wall and prevent damage due to scouring of the melt.

5. The uniform foaming extrusion die for an automobile engine cover according to claim 2, characterized in that: The porous ceramic damping sheet (26) has a porosity of 45-65% and a pore size of 0.05-0.25 mm, and a honeycomb support frame is embedded inside the porous ceramic damping sheet (26). The honeycomb support frame is made of silicon carbide material and has a wall thickness of 20-33% of the pore diameter, forming a graded filtering structure.

6. The uniform foaming extrusion die for an automobile engine cover according to claim 1, characterized in that: A double-pass sealing structure is provided at the joint surface between the upper mold (4) and the lower mold (5), comprising an outer metal labyrinth sealing ring (34) and an inner silicon nitride ceramic sealing strip (35); the metal labyrinth sealing ring (34) is provided with three layers of staggered sawtooth structures, with a spacing between adjacent sawtooths of 0.8-1.2 mm, thereby forming a non-contact dynamic seal.

7. The uniform foaming extrusion die for an automobile engine cover according to claim 2, characterized in that: The ball-jointed adjustment mechanism (28) is integrated with a micro servo motor (37) and an angle encoder (38); the micro servo motor (37) drives the extruder head (27) through a worm gear transmission mechanism (39) to perform three-dimensional angle fine-tuning within a range of ±15°, with an angle resolution of 0.1°; the angle encoder (38) and the PID control module (19) form a closed-loop feedback system.

8. The uniform foaming extrusion die for an automobile engine cover according to claim 1, characterized in that: An ejection mechanism is provided at the bottom of the molding cavity (8), the ejection mechanism comprising a hydraulic cylinder (41), and the outer wall of the hydraulic cylinder (41) is mounted in an engaging manner inside the lower mold (5); an installation chamber (43) is provided on the inner bottom wall of the molding cavity (8), and the inner wall of the installation chamber (43) is mounted on the outer wall of the hydraulic cylinder (41).

9. The method for using a uniform foaming extrusion die for an automobile engine cover according to claim 7, characterized in that: The working steps of the uniform foaming extrusion die for the automobile engine cover are as follows: S1, injecting the molten foaming material into the main feed channel (9) through the flange type constant temperature interface (44) by an extruder; S2, the embedded thermocouple array (18) monitors the temperature in real time at 3-5 groups of temperature measuring points distributed longitudinally along the molding cavity (8), and the PID control module (19) dynamically adjusts the power of the spiral heating tube (17) and the coolant flow rate of the spiral cooling tube (42) according to the temperature data, so as to establish an alternating heating or cooling gradient field along the circumference of the molding cavity (8) to ensure the melt fluidity and foaming uniformity; S3, first stage diffusion: the melt enters the first stage fan-shaped diffusion cavity (13), diffuses initially and changes the flow direction, forming a uniform basic flow field; Second-stage flow guide: guiding the melt to flow in a directional manner through the second-stage flow guide fins (14) to adjust the flow distribution to different areas; Third-stage path enhancement: the melt enters the third-stage corrugated flow channel (15), which extends the flow path and increases the contact area, thereby promoting uniform dispersion of the foaming agent; S4, a multi-stage pressure buffer (20) in the main feed channel (9) balances pressure fluctuations through alternating tapered sections (22) and gradually expanding sections (23), and a 0.2-0.4 mm annular groove (25) is provided on the inner wall of the turbulence suppression ring (24), and a porous ceramic damping plate (26) embedded in the groove further absorbs turbulent energy and stabilizes the melt flow state; S5, the eight extrusion heads (27) of the adjustable extrusion terminal (21) are finely adjusted in three dimensions through a ball-jointed adjustment mechanism (28), which is achieved by a micro servo motor (37) driving a worm gear transmission mechanism (39), and the angle encoder (38) and the PID control module (19) form a closed-loop feedback to adjust the extrusion direction in real time to match the complex contour of the engine cover; S6, the upper mold (4) and the lower mold (5) are precisely molded together through the mounting groove (6) to form a molding cavity (8) that matches the contour of the engine cover. The melt is uniformly foamed under the synergistic effect of temperature gradient, flow optimization and pressure compensation. The temperature, pressure and angle parameters of the extruder head (27) are monitored in real time and dynamically adjusted through the PID control module (19) to ensure the foaming density and dimensional accuracy.

10. The method for using the uniform foaming extrusion die for an automobile engine cover according to claim 9, characterized in that: The S3 also includes the following steps: S31, transition optimization: the arc-shaped transition surface (16) between the two-stage structure reduces the turbulence intensity and lowers the flow resistance; The step S5 also includes the following steps: S51. Each extruder head (27) is equipped with a pressure compensation ring (29), and eight internal pressure equalizing holes (30) equalize the local pressure to ensure that the melt evenly fills the molding cavity (8).

Images