Automobile door anti-collision plate and automobile door thereof

Abstract

The invention discloses a vehicle door anti-collision plate which comprises an outer-layer steel plate, a middle-layer honeycomb core and an inner-layer plate which are sequentially arranged, and the outer-layer steel plate, the middle-layer honeycomb core and the inner-layer plate are glued and then are subjected to hot-pressing curing to form an integrated anti-collision plate structure. A set of steel plate gluing grooves are formed in the outer side of the outer-layer steel plate in the length direction, and normal-temperature expansion glue is smeared in the steel plate gluing grooves. The invention further discloses an automobile door which comprises an automobile door inner plate, an automobile door outer plate and the automobile door anti-collision plate, the two ends of the anti-collision plate are fixed to the automobile door inner plate through fasteners, and the outer-layer steel plate is connected with the automobile door outer plate through the normal-temperature expansion glue in the surface groove. A three-layer structure with rigid outside and flexible inside is adopted, the arrangement space of the automobile door is effectively saved, and automobile door modeling design optimization is assisted; the three layers of materials adopt the combination of the elasticity modulus and the density index gradient, the weight reduction target is achieved, an ordered energy absorption path is formed, the Y-direction invasion amount during collision can be remarkably reduced, and the anti-collision performance is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive door technology, and in particular to a door anti-collision plate and an automotive door thereof. Background Technology

[0002] Traditional car door crash barriers are usually made of steel. Although they are strong, they are also heavy. The Y-axis dimension (the direction from the outside of the door to the inside of the door, hereinafter referred to as Y-axis) of steel crash barriers is usually around 35mm, which will have a certain impact on the fuel economy, door space layout and styling design of the car.

[0003] Traditional car door crash barriers often use high-strength steel solid beams, which suffer from problems such as heavy weight, high cost, large Y-axis dimensions, or complex manufacturing processes; while some plastic composite material crash barrier structures lack sufficient rigidity. For example, patent CN213831295U discloses a car door crash barrier, which is a steel thermoformed crash barrier with a cross-section that gradually decreases in size from the middle to both ends, and a Y-axis cross-sectional dimension of 30-35mm, resulting in only moderate weight reduction. Another example is a novel car door crash barrier disclosed in patent CN207190755U, where the main body forms a W-shaped cross-section structure through grooves and bosses on the plate surface, and multiple glue-applying grooves are provided on the back of the grooves, with a width of approximately 100-110mm, but the weight reduction effect is also only moderate. Yet another example is a novel thermoformed car door crash barrier disclosed in patent CN113335210A, where a steel thermoformed substrate is covered with impregnated fiber reinforcement, which has a certain weight reduction effect, but the large Y-axis space is not conducive to the arrangement inside the car door. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a door anti-collision plate and a car door thereof, which are lightweight and occupy little space.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A car door anti-collision plate includes an outer steel plate, a middle honeycomb core, and an inner plate arranged sequentially. The outer steel plate, the middle honeycomb core, and the inner plate are glued together and then cured by hot pressing to form an integrated anti-collision plate structure.

[0006] Further or preferred: The outer steel plate has a thickness range of 0.8-1mm, the middle honeycomb core has a thickness range of 10-15.5mm, and the inner plate has a thickness range of 1-1.5mm.

[0007] The inner layer is an injection-molded inner layer structure with glass fiber.

[0008] A set of steel plate adhesive grooves is provided on the outer side of the outer steel plate along its length, and room temperature expanding adhesive is applied into the steel plate adhesive grooves.

[0009] The outer surface of the outer steel plate is provided with a set of micro-pit structures, and the micro-pit Ra of the micro-pit structures ranges from 1.2 to 1.6 μm.

[0010] The intermediate honeycomb core has a honeycomb core structure with uneven thickness, being lower at both ends and higher in the middle.

[0011] The inner surface of the outer steel plate is provided with a set of sink platform structures to increase the frictional force matching the honeycomb core.

[0012] The outer steel plate has steel plate flanges on both sides, and the inner plate has inner plate flanges on both sides. The steel plate flanges and the inner plate flanges are fitted together by a snap-fit ​​structure.

[0013] The outer steel plate, the middle honeycomb core, and the inner plate are all provided with relatively aligned positioning holes.

[0014] A car door includes an inner door panel, an outer door panel, and a door anti-collision plate as described above. The two ends of the anti-collision plate are fixed to the inner door panel by fasteners, and the outer steel plate is connected to the outer door panel by room temperature expansion adhesive in the surface groove.

[0015] Compared with the prior art, the present invention has the following advantages: The door anti-collision plate and its structural design are reasonable, adopting a three-layer structure with an outer rigidity and an inner flexibility. The maximum overall Y-axis dimension is only 18mm, which effectively saves door layout space and helps optimize door styling design. The three layers of materials use a gradient combination of elastic modulus and density index to achieve weight reduction and form an orderly energy absorption path, which can significantly reduce Y-axis intrusion during a collision and improve anti-collision performance. The overall structure takes into account structural strength, lightweight, ease of assembly and cost control, and has excellent anti-collision buffering effect. Attached Figure Description

[0016] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings: Figure 1 This is a schematic diagram of the anti-collision plate structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the explosion of the anti-collision plate of the present invention.

[0018] Figure 3 This is a schematic diagram showing the connection between the anti-collision plate and the vehicle door of the present invention.

[0019] Figure 4 This is a schematic diagram of the three-layer cross-section adhesive coating of the anti-collision plate of the present invention.

[0020] In the picture: 1-Outer steel plate; 101-Steel plate recess; 102-Projection weld nut; 103-Steel plate secondary positioning hole; 104-Steel plate main positioning hole; 105-Steel plate side elongated hole; 106-Steel plate glue coating groove; 2-Intermediate layer honeycomb core; 201-Honeycomb core secondary positioning hole 3; 202-Honeycomb core main positioning hole; 3-Inner layer plate; 301-Side retaining pin; 302-Inner layer secondary positioning hole; 303-Inner layer main positioning hole; 4-Room temperature expanding adhesive; 501 - High-strength structural adhesive for the side holes of the outer steel plate and the side pins of the inner plate; 502 - High-strength structural adhesive between the outer steel plate and the middle honeycomb core; 502 - High-strength structural adhesive between the middle honeycomb core and the inner plate. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and through the description of the examples.

[0022] Although the invention has been shown and described herein with reference to specific embodiments, it is not intended to be limited to the details shown. Rather, various modifications in detail may be made within the equivalent scope and scope of the claims without departing from the invention. In the drawings, the same item numbers refer to the same elements.

[0023] Throughout this disclosure, various terms are used to describe the physical shape or arrangement of features. Many of these terms are used to describe features conforming to a cylindrical or generally cylindrical geometry with the feature as its radius and a central axis perpendicular to that radius. Unless otherwise specified, the terms are given the following meanings: The terms “longitudinal,” “longitudinal,” “axial,” and “axial” refer to a direction, dimension, or orientation parallel to the central axis. The terms “radial” and “radially” refer to a direction, dimension, or orientation perpendicular to the central axis. The terms “inward” and “inner” refer to a direction, dimension, or orientation extending radially toward the central axis. The terms “outward” and “outer” refer to a direction, dimension, or orientation extending radially away from the central axis.

[0024] In this specification, relative terms such as “horizontal,” “vertical,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontal,” “downward,” “upward,” etc.) should be interpreted as referring to the direction described or the direction shown in the accompanying drawings. These relative terms are for ease of description and are not generally intended to require a specific direction.

[0025] Most existing automotive door technologies have not yet solved the balance issues of lightweighting, large space occupation in the Y-direction (the direction from the outside of the door to the inside of the door, hereinafter referred to as Y-direction), and collision performance; therefore, this invention provides a comprehensive door anti-collision plate solution that integrates material innovation and structural optimization.

[0026] like Figures 1 to 4 As shown, a lightweight, composite material door anti-collision plate structure based on aluminum or steel-aluminum hybrid door is disclosed. The anti-collision plate is composed of three different materials of different thicknesses. It can improve the problems of large weight, large space occupation in the Y direction, and poor side impact performance of car door anti-collision plates.

[0027] The present invention provides a door anti-collision plate, comprising an outer steel plate 1, a middle honeycomb core 2, and an inner plate 3 arranged sequentially. The outer steel plate, the middle honeycomb core, and the inner plate are glued together and then cured by hot pressing to form an integrated anti-collision plate structure.

[0028] Preferably, the outer steel plate has a thickness range of 0.8-1mm, the middle honeycomb core has a thickness range of 10-15.5mm, and the inner plate has a thickness range of 1-1.5mm. The door anti-collision plate of the present invention can effectively reduce weight, reducing weight by about 15%-20% compared with most traditional steel hot-formed anti-collision plates; the overall maximum Y-axis dimension is 18mm, which can reduce the Y-axis space dimension by more than 90% compared with traditional steel beams; it has good collision performance, reducing the side impact intrusion by about 10%-15% compared with traditional steel beams; it has good process compatibility, adapting to existing door production lines, requiring only the addition of hot pressing tooling.

[0029] The inner layer is an injection-molded inner layer structure with glass fiber, which improves the structural strength and is fixed to the intermediate honeycomb core with structural adhesive.

[0030] A set of steel plate adhesive grooves 106 is provided on the outer side of the outer steel plate along the length direction. The steel plate adhesive grooves can be reasonably set according to the structural length of the anti-collision plate. The steel plate adhesive grooves are coated with room temperature expanding adhesive 4. The room temperature expanding adhesive can be an existing room temperature expanding adhesive material. The expanding adhesive is used to fix the car door panel together, making the structure stable and reliable, and can effectively avoid abnormal noise.

[0031] The outer surface of the outer steel plate is provided with a set of micro-pit structures, and the micro-pit Ra of the micro-pit structures ranges from 1.2 to 1.6 μm; the micro-pit structures are self-lubricating micro-pits, which can effectively reduce the coefficient of friction.

[0032] The inner surface of the outer steel plate is provided with a set of recessed platform structures to increase the frictional force matching with the honeycomb core; specifically, the inner surface of the outer steel plate and the honeycomb core are fixed together by adhesive, and the frictional force between the two is increased by setting the steel plate recessed platform 101, so that the fixation is reliable.

[0033] The middle layer honeycomb core 2 is a honeycomb core structure with uneven thickness, being lower at both ends and higher in the middle; specifically, the middle layer honeycomb core is a plastic honeycomb core structure, which is lightweight.

[0034] The outer steel plate, the middle honeycomb core, and the inner plate are all provided with relatively aligned positioning holes; specifically, the outer steel plate is provided with a steel plate secondary positioning hole 103 and a steel plate main positioning hole 104, the middle honeycomb core is provided with a honeycomb core secondary positioning hole 201 and a honeycomb core main positioning hole 202, and the inner plate is provided with an inner plate secondary positioning hole 302 and an inner plate main positioning hole 303; the steel plate secondary positioning holes, the honeycomb core secondary positioning holes, and the inner plate secondary positioning holes are relatively aligned, and the steel plate main positioning holes, the honeycomb core main positioning holes, and the inner plate main positioning holes are relatively aligned.

[0035] The outer steel plate has steel plate flanges on both sides, and the inner plate has inner plate flanges on both sides. The steel plate flanges and inner plate flanges are fitted together by a snap-fit ​​structure. The outer steel plate and inner plate together form a cavity structure, and the middle honeycomb core is located inside the cavity structure, making the structure stable and reliable.

[0036] Preferably, the outer steel plate has an elongated hole 105 on the side flange of the steel plate, and the inner plate has a protruding side locking pin 301 on the side flange of the inner plate. The side locking pin and the elongated hole on the side of the steel plate are engaged and matched, which makes assembly simple and the structure stable and reliable.

[0037] The door anti-collision plate is a long strip structure with a fixed end structure. The end structure has mounting holes or welded nuts 102. The anti-collision plate is fixed to the door panel by tightening the nuts through the mounting holes or welded nuts. Specifically, the outer steel plate has an extension end plate at its end. The extension end plate is flat and the flat structure can ensure a close fit with the door panel and a stable and reliable fixation. The outer steel plate forms a step on the inner side of the extension end plate. The end of the inner plate has a folded structure. The folded structure cooperates with the step to form a sealed cavity structure between the outer steel plate and the inner plate. The core is located inside the sealed cavity structure.

[0038] like Figure 4 As shown, the outer steel plate and the middle honeycomb core are bonded together by a high-strength structural adhesive 502 between the outer steel plate and the middle honeycomb core, and the inner plate is bonded to the middle honeycomb core by a high-strength structural adhesive 502 between the middle honeycomb core and the inner plate; the outer steel plate side and the inner plate side have a high-strength structural adhesive 501 with side holes of the outer steel plate and side pins of the inner plate, which are fixed by hot pressing; the gap between the pin and the elongated hole is filled with high-strength structural adhesive to form a snap-fit ​​+ adhesive composite connection, and the snap-fit ​​gap is sealed with adhesive, so that the structure is stable and reliable.

[0039] like Figure 3As shown, the present invention provides a car door, including an inner door panel, an outer door panel, and a door anti-collision plate as described above. The two ends of the anti-collision plate are fixed to the inner door panel by fasteners. The outer steel plate is connected to the outer door panel by room temperature expanding adhesive in the surface groove. The room temperature expanding adhesive will expand when applied to the surface groove of the outer steel plate and will be tightly connected to the outer door panel, which can effectively prevent abnormal noise.

[0040] This invention relates to a door anti-collision plate and its structural design for automobile doors. It adopts a three-layer structure with an outer rigidity and an inner flexibility, with a maximum overall Y-axis dimension of only 18mm, effectively saving door layout space and contributing to the optimization of door styling design. The three layers of materials use a gradient combination of elastic modulus and density index, achieving both weight reduction and forming an ordered energy absorption path, which can significantly reduce Y-axis intrusion during a collision and improve anti-collision performance. The overall structure takes into account structural strength, lightweight, ease of assembly, and cost control, and has excellent anti-collision buffering effect.

[0041] The door anti-collision panel of this invention adopts a three-layer composite structure, consisting of an outer steel plate, a middle honeycomb core, and an inner panel arranged sequentially. The three layers are bonded together and then heat-pressed to form an integral structure. The outer steel plate is 0.8-1mm thick, the middle plastic honeycomb core is 10-15.5mm thick (with unequal thickness at both ends and in the middle), and the inner panel is a glass fiber injection-molded board (1-1.5mm thick), which is reinforced with glass fiber and bonded to the honeycomb core.

[0042] The outer steel plate has a groove for applying adhesive (with room-temperature expanding adhesive inside, used to fix it to the door panel and prevent noise). Its outer surface has self-lubricating micro-pits with a thickness of Ra 1.2-1.6μm (reducing the coefficient of friction), and its inner surface has a recessed structure (increasing friction with the honeycomb core). Both sides have flanges with elongated holes. The inner plate has flanges with side locking pins on both sides, which engage with the steel plate flanges to form a sealed cavity to accommodate the honeycomb core. All three components have aligned main and auxiliary positioning holes for easy assembly and positioning.

[0043] This anti-collision plate boasts significant core advantages: it reduces weight by 15%-20% compared to traditional hot-formed steel anti-collision plates; its maximum Y-axis dimension is only 18mm, more than 90% smaller than traditional steel beams; side impact intrusion is reduced by 10%-15%; and it offers good process compatibility, fitting existing car door production lines with only the addition of hot-pressing tooling. Furthermore, this invention also discloses a car door incorporating this anti-collision plate. The anti-collision plate is fixed to the inner door panel at both ends with fasteners, and the outer steel plate is connected to the outer door panel using room-temperature expanding adhesive. The overall structural design is reasonable, optimizing door layout space while balancing structural strength, ease of assembly, and cost control.

[0044] like Figures 1 to 4 As shown, a preferred embodiment of the present invention is as follows: This invention discloses a structure for a crash barrier, such as... Figure 1As shown, the overall structure of the crash barrier resembles a sandwich structure with a rigid outer layer and a flexible inner layer. Figure 2 The diagram shows a three-layer exploded view. The outermost steel plate 1 is 1mm thick. The middle honeycomb core 2 has a height varying from 10-15.5mm. The innermost plate 3 is a 1.5mm thick PA6 plate. The overall maximum Y-axis dimension is 18mm, which effectively saves space in the door and also facilitates door design. The elastic modulus of the three layers of the anti-collision plate changes exponentially: 200GPa (steel) → 0.5GPa (honeycomb core material) → 15GPa (PA6), with corresponding density gradients of 7.8g / cm³ → 0.06g / cm³ → 1.4g / cm³. This material combination not only reduces weight appropriately, but also, in the event of a door collision, the steel layer undergoes plastic deformation first, followed by honeycomb crushing, and finally the PA6 layer fibers are pulled out. This energy absorption and transfer path forms an effective buffer, reducing the amount of Y-axis intrusion.

[0045] like Figure 2 As shown, the main structure of the crash barrier includes a 1.0mm thick outer steel plate 1. The outer steel plate 1 uses self-lubricating micro-pits (Ra=1.2-1.6μm), reducing the surface friction coefficient to 0.15, thus eliminating the need for electrophoresis. The material used is DP590 duplex steel (tensile strength ≥590MPa). The middle honeycomb core 2 is a PP60 honeycomb core with a thickness of 10mm-15mm (lower at both ends and higher in the middle), formed by CNC milling. The main unit of the honeycomb core is a hexagon with a side length of 4.8mm and a thickness of 1.2mm. The inner plate 3 is a 1.5mm thick PA6 with 30% glass fiber content.

[0046] in, Figure 2 The outer steel plate 1 shown is cold-stamped and formed, and four M8 nuts 102 are projected onto both ends. The steel plate body includes many steel plate counters 101 with a depth of 1mm and a diameter of 6mm (the function is to increase the friction force to match the honeycomb core), main positioning holes 104, secondary positioning holes 103, three steel plate adhesive grooves 106 (which also serve the function of energy absorption), and 20 2mm*4mm elongated holes 105 on both sides of the steel plate. Figure 2 The intermediate layer honeycomb core 2 shown includes a honeycomb core main positioning hole 202 and a honeycomb core secondary positioning hole 201. Figure 2 The inner layer plate 3 shown is injection molded and includes an inner main positioning hole 302, an inner secondary positioning hole 303, and 20 side retaining pins 301 with a diameter of 1.5 mm and a height of 1 mm on both sides.

[0047] This application also discloses the overall processing technology of the anti-collision plate; firstly, after the inner layer plate 3 is injection molded, the inner bottom surface and the two inner sides are coated with a layer of about 0.2mm thickness (e.g., Figure 4The high-strength structural adhesive (main components: bisphenol A epoxy resin, polyetheramine curing agent, nano-diamond powder, carbon fiber woven mesh, silane coupling agent) in area 503 (shown) is then fixedly placed into the hot press fixture. During placement, the inner layer main positioning hole 302 and inner layer secondary positioning hole 303 are aligned with the main and secondary positioning pins on the hot press fixture itself. Next, the surface of the middle layer honeycomb core 2 is plasma-treated (Ar / O2 mixed gas) and then fixedly assembled with the inner layer plate 3 through its own honeycomb core main positioning hole 202 and honeycomb core secondary positioning hole 201. Then, about 0.2mm (e.g., ...) is also applied to the inner bottom surface and two inner sides of the steel plate. Figure 4 The high-strength structural adhesive (areas 501 and 502 shown) is assembled and fixed together with the intermediate layer and inner layer plate through the main positioning hole 104 and the secondary positioning hole 103 of the steel plate. During assembly, it is necessary to ensure that all the side locking pins 301 on both sides of the inner layer plate are inserted into the corresponding 20 elongated holes of the outer steel plate 1. The gaps around the side locking pins 301 and the elongated holes will be filled with a certain amount of high-strength structural adhesive during the assembly process. Finally, the mold is closed, and the entire anti-collision plate is hot-pressed and cured (parameters: 100-150℃, 1-3MPa, holding time 30-60s) until the high-strength adhesive is completely cured. The manufacturing process is simple and the cost is relatively low.

[0048] like Figure 1 As shown, considering the melting points of the honeycomb core and PA6, the anti-collision plate cannot be baked at high temperatures along with the door assembly. The anti-collision plate described in this application is based on an aluminum or steel-aluminum hybrid door, and both ends of the anti-collision plate need to be bolted and fixedly installed to the inner panel of the door. Figure 3 As shown, to prevent rattling between the crash barrier and the outer door panel, a certain amount of room-temperature expanding adhesive 4 needs to be applied to the three grooves on the surface of the crash barrier. This adhesive is a single-component moisture-curing polyurethane expanding adhesive, whose main components include polyurethane prepolymer, foaming agent, catalyst, and filler. This room-temperature expanding adhesive relies entirely on ambient moisture for curing and requires no baking equipment. It begins to expand significantly within 5-30 minutes after extrusion, and the final expansion ratio can reach 2-4 times or higher. Initial curing is completed within 2-4 hours, and complete curing to reach final strength requires 24-48 hours.

[0049] The preferred specific components of the overall structure of this invention are as follows: Outer steel plate: The outer steel plate, as the "rigid protective layer" of the anti-collision plate, mainly bears the impact force transmission and initial plastic deformation energy absorption in the early stage of the side collision. At the same time, as the connecting carrier between the anti-collision plate and the outer door panel, it needs to have sufficient strength, formability and adhesive compatibility. DP590 duplex steel is selected. This material has a tensile strength ≥590MPa, moderate yield strength, and excellent cold stamping performance. It can meet the rigidity requirements during side impacts and can also form the necessary structures such as flanges, countersunk areas, and adhesive grooves through cold stamping. It also has good compatibility with high-strength structural adhesives and room-temperature expanding adhesives, minimizing the risk of delamination. The steel plate thickness is 0.8-1mm, selected based on a balance between strength and lightweight. Thickness <0.8mm results in insufficient rigidity of the outer steel plate, leading to excessive deformation during side impacts and hindering effective transmission of impact force to the honeycomb core. Thickness >1mm increases the overall weight of the crash panel, making it impossible to achieve the 15%-20% weight reduction target, and also increases the difficulty of cold stamping. A thickness of 1.0mm is preferred, balancing strength, lightweight, and formability. Cold stamping is compatible with existing door steel plate stamping production lines, eliminating the need for additional dedicated forming equipment. Only a dedicated stamping die needs to be designed according to the crash panel structure, resulting in relatively low manufacturing costs.

[0050] Intermediate honeycomb core: The middle honeycomb core, as the "core energy-absorbing layer" of the crash barrier, mainly undertakes the crushing energy absorption function during side impacts. At the same time, as the connecting bridge between the outer steel plate and the inner plate, it needs to have the characteristics of light weight, high compressive strength, stable energy absorption effect, and controllable thickness. It is a key component to achieve lightweighting and improved side impact performance. PP60 plastic honeycomb core is selected. This material is lightweight (density only 0.06g / cm³), has moderate compressive strength, good toughness, and is easy to process and mold. It also has excellent adhesion to high-strength structural adhesives. After plasma treatment, its surface activity is enhanced, which can further improve the adhesion reliability with the outer steel plate and inner plate. In addition, the melting point of PP60 material is suitable for hot pressing curing process (hot pressing temperature 100-150℃, lower than the melting point of PP60), and there will be no melting or deformation problems during hot pressing. The honeycomb core thickness is 10-15.5mm, selected based on "energy absorption effect and space adaptation". When the thickness is <10mm, the honeycomb core has insufficient crushing and energy absorption space, which cannot effectively absorb the side impact force, resulting in the side impact intrusion not meeting the requirements. When the thickness is >15.5mm, the overall Y-axis dimension of the anti-collision plate will exceed 18mm, making it impossible to achieve the space optimization goal. At the same time, an unequal thickness design with "low at both ends and high in the middle" is adopted. The thickness at both ends can be controlled at 10-12mm, and the thickness in the middle can be controlled at 13-15.5mm. The selection basis is to adapt to the "narrow at both ends and wide in the middle" spatial contour of the car door. At the same time, the thickness in the middle can improve the energy absorption capacity of the core area, while the thinness at both ends facilitates the cooperation with the end structure of the outer steel plate and the inner plate to form a sealed cavity.

[0051] The honeycomb core is formed by CNC milling. The main unit is a regular hexagon with a side length of 4.8mm and a wall thickness of 1.2mm. The selection of this structure is based on "optimal energy absorption efficiency". The regular hexagonal structure can evenly distribute the impact force, and the force is uniform during crushing, resulting in stable energy absorption. Compared with square and round honeycomb units, the energy absorption efficiency is increased by 10%-15% at the same thickness. The combination of a side length of 4.8mm and a wall thickness of 1.2mm can minimize the weight while ensuring the compressive strength of the honeycomb core (≥1.5MPa).

[0052] Inner layer: The inner layer plate, as the "auxiliary protection and sealing layer" of the anti-collision plate, mainly undertakes the secondary energy absorption function in the later stage of side impact. At the same time, it works with the outer steel plate to form a sealed cavity to protect the middle honeycomb core. It needs to have sufficient strength, toughness and injection molding performance. PA6 injection molding sheets with 30% glass fiber reinforcement are selected. PA6 material has good toughness, impact resistance, and excellent injection molding performance, and can be molded into complex structures such as flanges, pins, and positioning holes. Adding 30% glass fiber can significantly improve the structural strength of the inner layer sheet (tensile strength ≥80MPa), preventing the inner layer sheet from breaking or being damaged during side impacts. At the same time, the addition of glass fiber can reduce the shrinkage rate of PA6, improve the dimensional accuracy of injection molded parts, and ensure the assembly compatibility with the middle honeycomb core and the outer steel plate.

[0053] The inner layer plate thickness should be 1-1.5mm, selected based on "strength and assembly compatibility." If the thickness is less than 1mm, the inner layer plate lacks sufficient strength and is easily damaged during side impacts, failing to provide effective secondary energy absorption. If the thickness is greater than 1.5mm, it increases the overall weight and prevents the inner layer plate's flange from precisely fitting with the outer steel plate's flange, affecting the formation of the sealing cavity. A thickness of 1.5mm is preferred, balancing strength and assembly feasibility.

[0054] In optional examples, the connection between the crash barrier and the inner door panel can be configured with different overlap relationships. In this example, the crash barrier and the inner door panel are bolted together; however, riveting can also be considered if factors such as process and cost are taken into account. Furthermore, the density of the recessed areas on the outer steel plate surface, the density of the honeycomb core, and the parameters of the hot-pressing curing can be appropriately increased or decreased. The formulations of the high-strength structural adhesive and the room-temperature expanding adhesive can also be appropriately adjusted in proportion; this application does not impose explicit limitations in these aspects.

[0055] The present invention has the following advantages: 1. Significant advantages of lightweight design It adopts a three-layer composite structure of outer steel plate + middle plastic honeycomb core + glass fiber injection molded inner plate to replace the traditional steel thermoformed anti-collision beam; compared with the traditional steel anti-collision plate, it reduces weight by 15% to 20%, meeting the requirements for lightweight vehicle doors; the middle layer uses low-density plastic honeycomb core to further reduce the overall weight; 2. It occupies very little space, which is conducive to the arrangement and design of car doors. The overall Y-axis (door thickness direction) maximum dimension is only 18mm; compared with the traditional steel beam structure, the Y-axis space occupancy is reduced by more than 90%; it greatly saves the interior layout space of the door, which is conducive to the optimization of door shape and interior / exterior panel curved surface design; 3. Significantly improved side-impact protection and energy absorption performance. Employing a sandwich structure with an outer rigid and inner flexible core, the materials feature a gradient combination of elastic modulus and density: steel (high modulus, high strength) → honeycomb core (low modulus, high energy absorption) → glass fiber reinforced inner layer (medium modulus, high toughness). This creates an ordered energy absorption path during impact: plastic deformation of the steel plate → honeycomb crushing and energy absorption → fiber pull-out buffering in the inner layer. This reduces Y-axis intrusion by 10%–15% during side impacts, enhancing occupant protection and structural safety. The outer steel plate uses DP590 duplex steel with a tensile strength ≥590MPa, ensuring the rigidity of the external support. 4. The structure is ingeniously designed and stable and reliable. The inner surface of the outer steel plate features a recessed platform structure to enhance the bonding friction with the honeycomb core, resulting in a more secure connection. The outer and inner plates have flanged edges and snap-fit ​​structures (pins and elongated holes) on both sides, forming a sealed cavity to enclose the honeycomb core, enhancing overall rigidity and integrity. All three layers have alignment holes for precise assembly and positioning, preventing misalignment. The outer steel plate has an adhesive groove and room-temperature expanding adhesive on its outer side, allowing it to expand and adhere to the door panel, effectively eliminating rattles. The outer surface has self-lubricating micro-pits (Ra 1.2–1.6μm) with a friction coefficient as low as 0.15, eliminating the need for an electrophoresis process. 5. Strong process compatibility, easy mass production, and controllable cost. The process employs a combination of adhesive bonding and thermoforming for integrated molding, resulting in a simple process with a short holding time (30–60 seconds), facilitating mass production. Only the addition of thermoforming tooling is required, making it highly compatible with existing aluminum / steel-aluminum hybrid door production lines without significant modifications. The room-temperature expanding adhesive cures via moisture, eliminating the need for high-temperature baking of the door assembly and preventing the honeycomb core and inner panels from melting or deforming due to heat. Bolts / riveting can be flexibly used to connect to the inner door panel, offering flexible process options. The honeycomb core can be CNC machined, and the inner panels injection molded, ensuring controllable material and process costs.

[0056] The above description is merely an illustration of preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0057] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the concept and technical solution of the present invention, or the direct application of the concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A door anti-collision plate, characterized in that: It includes an outer steel plate, a middle honeycomb core, and an inner plate arranged in sequence. The outer steel plate, the middle honeycomb core, and the inner plate are glued together and then cured by hot pressing to form an integrated anti-collision plate structure.

2. The door anti-collision plate as described in claim 1, characterized in that: The outer steel plate has a thickness range of 0.8-1mm, the middle honeycomb core has a thickness range of 10-15.5mm, and the inner plate has a thickness range of 1-1.5mm.

3. The door anti-collision plate as described in claim 1, characterized in that: The inner layer is an injection-molded inner layer structure with glass fiber.

4. The door anti-collision plate as described in claim 1, characterized in that: A set of steel plate adhesive grooves is provided on the outer side of the outer steel plate along its length, and room temperature expanding adhesive is applied into the steel plate adhesive grooves.

5. The door anti-collision plate as described in claim 1, characterized in that: The outer surface of the outer steel plate is provided with a set of micro-pit structures, and the micro-pit Ra of the micro-pit structures ranges from 1.2 to 1.6 μm.

6. The door anti-collision plate as described in claim 1, characterized in that: The intermediate honeycomb core has a honeycomb core structure with uneven thickness, being lower at both ends and higher in the middle.

7. The door anti-collision plate as described in claim 1, characterized in that: The inner surface of the outer steel plate is provided with a set of sink platform structures to increase the frictional force matching the honeycomb core.

8. The door anti-collision plate as described in claim 1, characterized in that: The outer steel plate has steel plate flanges on both sides, and the inner plate has inner plate flanges on both sides. The steel plate flanges and the inner plate flanges are fitted together by a snap-fit ​​structure.

9. The door anti-collision plate as described in claim 1, characterized in that: The outer steel plate, the middle honeycomb core, and the inner plate are all provided with relatively aligned positioning holes.

10. A car door, comprising an inner door panel and an outer door panel, characterized in that: It also includes a door anti-collision plate as described in any one of claims 1 to 9, wherein the two ends of the anti-collision plate are fixed to the inner panel of the door by fasteners, and the outer steel plate is connected to the outer panel of the door by room temperature expansion adhesive in the surface groove.

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