A flexible electromagnetic shielding composite structure for HOD steering wheel

Abstract

The utility model discloses a kind of flexible electromagnetic shielding composite structures for HOD steering wheel, including TPU base material, TPU base material side is provided with first adhesive layer, TPU base material other side is provided with conductive coating, the first adhesive layer side away from TPU base material is provided with conductive cloth layer, the conductive cloth layer side away from first adhesive layer is provided with second adhesive layer, this structure is sequentially laminated by conductive coating, TPU base material, acrylic pressure-sensitive adhesive, nickel-plated elastic conductive cloth and release layer, overall structure is soft and has excellent tensile property.Especially the excellent tensile property of nickel-plated elastic conductive cloth in 45 and 135 degree direction, combined with high adhesion acrylic pressure-sensitive adhesive, realize perfect fit with steering wheel surface, while providing excellent electromagnetic shielding efficiency.Meanwhile, material selection and interlayer structure are particularly optimized in this structure, solve the problems such as not firm, unstable shielding effect, poor durability, etc. that traditional shielding material is prone to appear in the application of automobile steering wheel.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicle component technology, specifically to a flexible electromagnetic shielding composite structure for HOD steering wheels. Background Technology

[0002] In the process of intelligentization of new energy vehicles, the HOD (Hands On Detection) steering wheel, as a core component of human-machine interaction, directly affects the stable operation of the vehicle's electronic system due to its electromagnetic compatibility (EMC) performance. Traditional steering wheel shielding layers often use copper foil or copper-plated fabric, which, while providing basic shielding, suffer from five major technical defects: Firstly, copper ions in the copper foil shielding layer / copper-plated fabric are prone to migration under high temperature and high humidity conditions, leading to signal distortion in the steering wheel electronic module; Secondly, the metal foil layer is prone to fatigue fracture when the steering wheel is repeatedly twisted; Third, existing technologies do not consider the synergistic bonding mechanism between the pressure-sensitive adhesive layer and the conductive cloth, which makes the multilayer structure prone to interface delamination in humid and hot environments. Fourth, conventional conductive coatings have poor wear resistance, and the coating is easily worn, which leads to fluctuations in the HOD signal.

[0003] Fifth, the steering wheel has a complex three-dimensional curved surface, and the existing shielding materials have poor tensile adaptability, making them prone to lifting and falling off after being pasted.

[0004] This requires the new shielding layer to overcome the dual bottlenecks of material selection and process adaptation, achieving both a copper-free design and ensuring the mechanical and electrical stability of each layer under extreme operating conditions. Therefore, this utility model addresses the shortcomings of existing technologies by providing a thin, flexible, highly effective, and well-fitting electromagnetic shielding composite structure for HOD steering wheels in new energy vehicles. Utility Model Content

[0005] The technical problem solved by this utility model is to provide a flexible electromagnetic shielding composite structure for HOD steering wheels with good flexibility and high shielding effectiveness.

[0006] The technical solution adopted by this utility model to solve its technical problem is: a flexible electromagnetic shielding composite structure for HOD steering wheels, including a TPU substrate, a first adhesive layer is provided on one side of the TPU substrate, a conductive coating is provided on the other side of the TPU substrate, a conductive cloth layer is provided on the side of the first adhesive layer away from the TPU substrate, and a second adhesive layer is provided on the side of the conductive cloth layer away from the first adhesive layer.

[0007] Furthermore, it also includes a release layer, which is located on the side of the second adhesive layer away from the conductive fabric layer.

[0008] Furthermore, the conductive coating is a carbon microcrystalline film conductive coating or a nickel-based conductive coating, and the thickness of the conductive coating is 1~5μm.

[0009] Furthermore, the TPU substrate is a thermoplastic polyurethane film, and the thickness of the TPU substrate is 0.01~2mm.

[0010] Furthermore, both the first adhesive layer and the second adhesive layer are acrylic pressure-sensitive adhesives, and the thickness of the first adhesive layer and the second adhesive layer is 0.03~0.1mm.

[0011] Furthermore, the conductive fabric layer is a nickel-plated elastic conductive fabric or a gold-plated conductive fabric, and the thickness of the conductive fabric layer is 0.02~0.5mm.

[0012] Furthermore, it also includes a grounding guide structure connected to a nickel-plated elastic conductive cloth. The grounding guide structure is made of metal wires fixed to the nickel-plated elastic conductive cloth in a V-shape or U-shape. The grounding guide structure is connected to an external vehicle grounding system through a wire.

[0013] Furthermore, the release layer is a polyester film, the release layer is a textured release film, and the thickness of the release layer is 0.025mm~0.075mm.

[0014] The beneficial effects of this invention are as follows: This structure is composed of a conductive coating, a TPU substrate, an acrylic pressure-sensitive adhesive, a nickel-plated elastic conductive cloth, and a release layer, layered sequentially. The overall structure is flexible and possesses excellent tensile strength. In particular, the excellent tensile strength of the nickel-plated elastic conductive cloth in the 45° and 135° directions, combined with the highly adhesive acrylic pressure-sensitive adhesive, achieves a perfect fit with the curved surface of the steering wheel, while providing superior electromagnetic shielding performance. Furthermore, this structure has specifically optimized material selection and interlayer structure, solving problems such as poor adhesion, unstable shielding effect, and poor durability that are common with traditional shielding materials in automotive steering wheel applications. This design combines flexibility, high shielding effectiveness, and environmental adaptability, making it suitable for the stringent electromagnetic shielding requirements of HOD systems in new energy vehicles.

[0015] Meanwhile, this structure combines a conductive coating and nickel-plated conductive cloth to form a dual shielding mechanism. The conductive coating mainly provides surface electromagnetic absorption, while the nickel-plated conductive cloth provides reflective shielding. The overall shielding effectiveness of this composite material is >60dB over a wide frequency range of 9kHz-8.5GHz, effectively ensuring the stable operation of the HOD system in complex electromagnetic environments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the flexible electromagnetic shielding composite structure for HOD steering wheels according to an embodiment of this application.

[0017] Figure 2This is a schematic diagram of the texture of nickel-plated elastic conductive cloth.

[0018] Figure 3 This is a schematic diagram showing the application position of this utility model on a steering wheel.

[0019] The components in the diagram are labeled as follows: 1. Conductive coating; 2. TPU substrate; 3. First adhesive layer; 4. Conductive cloth layer; 5. Second adhesive layer; 6. Release layer; 7. Skeleton; 8. Foam layer; 9. Heating layer; 10. Electromagnetic shielding layer; 11. Sensor layer; 12. Leather layer. Detailed Implementation

[0020] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, an embodiment of this application discloses a flexible electromagnetic shielding composite structure for HOD steering wheels, including a TPU substrate 2, a first adhesive layer 3 is provided on one side of the TPU substrate 2, a conductive coating 1 is provided on the other side of the TPU substrate 2, a conductive cloth layer 4 is provided on the side of the first adhesive layer 3 away from the TPU substrate 2, and a second adhesive layer 5 is provided on the side of the conductive cloth layer 4 away from the first adhesive layer 3. It also includes a release layer 6, which is located on the side of the second adhesive layer 5 away from the conductive cloth layer 4.

[0022] Specifically, this structure is composed of conductive coating 1, TPU substrate 2, acrylic pressure-sensitive adhesive, nickel-plated elastic conductive cloth and release layer 6 stacked in sequence. The overall structure is soft and has excellent tensile strength, while providing excellent electromagnetic shielding performance, which is suitable for the stringent electromagnetic shielding requirements of HOD systems in new energy vehicles.

[0023] In this embodiment, the conductive coating 1 is a carbon microcrystalline film conductive coating 1 or a nickel-based conductive coating 1, and the thickness of the conductive coating 1 is 1~5μm.

[0024] Specifically, in this embodiment, a carbon microcrystalline conductive coating 1 is selected, preferably with a thickness of 5 μm. Experimental testing shows that the surface resistance of the conductive coating 1 is <10 Ω. The shielding effectiveness of the carbon microcrystalline conductive coating 1 depends on the resistive loss characteristics of the carbon material, converting electromagnetic energy into heat energy through a conductive network for absorption. Simultaneously, highly conductive carbon structures (such as graphene) form reflective interfaces, significantly reflecting high-frequency electromagnetic waves. This type of coating can optimize the absorption ratio over a wide frequency range (e.g., 2-18 GHz) through impedance matching design. In practical applications, the carbon microcrystalline conductive coating 1, with its unique properties, can effectively cope with the complex electromagnetic environment of new energy vehicles. When the vehicle is in motion, various electronic devices generate electromagnetic waves of different frequencies, and this conductive coating 1 can convert the energy of these electromagnetic waves into heat energy over a wide frequency range, thereby reducing electromagnetic interference to the HOD steering wheel electronic module.

[0025] Furthermore, when selecting nickel-based conductive coating 1, its difference from carbon microcrystalline film is that carbon-based materials focus more on absorption at high frequencies, while nickel-based materials mainly reflect at low frequencies. However, both can play an electromagnetic shielding role when used in this composite structure.

[0026] In this embodiment, the TPU substrate 2 is a thermoplastic polyurethane film, and the thickness of the TPU substrate 2 is 0.01~2mm.

[0027] Specifically, the preferred thickness used in this embodiment is 0.1mm, with a tensile strength >25MPa and an elongation at break >450%. Its excellent tensile properties can perfectly adapt to the multi-directional stress requirements when wrapping the curved surface of the steering wheel. After pasting, there is no lifting or wrinkling, ensuring long-term reliability.

[0028] In addition, TPU substrate 2 can also be replaced with silicone rubber. Compared with TPU substrate 2, silicone rubber substrate has better temperature resistance and chemical stability, but its cost is slightly higher than that of TPU substrate 2.

[0029] In this embodiment, both the first adhesive layer 3 and the second adhesive layer 5 are acrylic pressure-sensitive adhesives, and the thickness of the first adhesive layer 3 and the second adhesive layer 5 is 0.03~0.1mm.

[0030] Specifically, in this embodiment, the preferred thickness is 0.05 mm. The selected acrylic pressure-sensitive adhesive has a peel force >2000 gf / inch and a holding force >72 hours without displacement. The adhesive layer is also conductive with a resistance <0.05 Ω, ensuring good interlayer conductivity and meeting temperature resistance requirements from -40 to 95°C. This prevents adhesion failure due to humid and hot environments, meeting automotive-grade application requirements.

[0031] In this embodiment, the conductive cloth layer 4 is a nickel-plated elastic conductive cloth or a gold-plated conductive cloth, and the thickness of the conductive cloth layer 4 is 0.02~0.5mm.

[0032] Specifically, this embodiment preferably uses a nickel-plated elastic conductive cloth with a thickness of 0.12mm. The nickel-plated elastic conductive cloth uses polyester fiber cloth as a base and forms a pure nickel plating layer without copper through an electroplating process, effectively avoiding the aging problem of copper-containing structures in high-temperature and high-humidity environments. Unlike traditional conductive cloths, this conductive cloth has an elongation rate of over 40% in both the 45° and 135° directions, perfectly adapting to the multi-directional stress requirements when wrapping the curved surface of a steering wheel. After application, it exhibits no lifting or wrinkling, ensuring long-term reliability. The nickel-plated conductive cloth has a rhomboid texture, a surface resistance of <0.5Ω, and a shielding effectiveness (@10MHz~3GHz) of 50dB. Furthermore, this structure does not contain copper, preventing oxidation in high-temperature and high-humidity environments.

[0033] Furthermore, when choosing gold-plated conductive cloth, it offers superior shielding effectiveness compared to nickel-plated conductive cloth in the 10MHz~3GHz range, typically ranging from 70-90dB. Specific performance is influenced by plating thickness, substrate density, and the test frequency band. Additionally, gold-plated conductive cloth exhibits greater stability under extreme conditions, but its cost is slightly higher than that of nickel-plated conductive cloth.

[0034] In this embodiment, a grounding guide structure connected to a nickel-plated elastic conductive cloth is also included. The grounding guide structure consists of metal wires fixed to the nickel-plated elastic conductive cloth in a V-shape or U-shape. The grounding guide structure is connected to an external vehicle grounding system via a wire. Specifically, the grounding guide structure is designed to guide the charge accumulated on the conductive cloth layer 4 to the external vehicle grounding system in a timely manner, thereby further enhancing the electromagnetic shielding effect. The metal wires are fixed in a V-shape or U-shape. This special shape design can increase the contact area between the metal wires and the nickel-plated elastic conductive cloth within a limited space, thereby improving the efficiency of charge conduction.

[0035] In this embodiment, the release layer 6 is a polyester film, the release layer 6 is a textured release film, and the thickness of the release layer 6 is 0.025mm~0.075mm.

[0036] Specifically, the textured surface of the release film faces the second adhesive layer 5, and the release film covers the adhesive surface, making the adhesive surface grid-like. Compared with ordinary adhesive, grid adhesive has the advantage of rapid air release, avoiding the formation of air bubbles that affect the appearance. In this embodiment, the preferred thickness of the textured release film is 0.05 mm. This release layer 6 covers the adhesive layer and can protect the adhesive surface from moisture erosion and dirt contamination, thereby affecting its performance.

[0037] In the specific fabrication of this structure, a conductive coating is applied to a TPU substrate using a microgravure coating method, forming a conductive coating approximately 5 μm thick. This conductive coating and the TPU substrate together constitute a conductive TPU film. A first adhesive layer and a second adhesive layer are then transferred onto a conductive fabric layer to create a conductive fabric double-sided adhesive. Finally, the conductive TPU film and the conductive fabric tape are laminated together to obtain the composite structure of this utility model patent.

[0038] When this structure is used on a HOD steering wheel, the HOD steering wheel is as follows: Figure 3 As shown, the HOD steering wheel includes the following structure from the inside out: frame 7, foam layer 8, heating layer 9, electromagnetic shielding layer 10, sensor layer 11, and leather layer 12. The electromagnetic shielding layer 10 includes a conductive coating 1, a TPU substrate 2, a first adhesive layer 3, a conductive cloth layer 4, and a second adhesive layer 5 arranged sequentially.

[0039] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A flexible electromagnetic shielding composite structure for HOD steering wheels, characterized in that: The TPU substrate (2) includes a first adhesive layer (3) on one side and a conductive coating (1) on the other side. A conductive cloth layer (4) is provided on the side of the first adhesive layer (3) away from the TPU substrate (2), and a second adhesive layer (5) is provided on the side of the conductive cloth layer (4) away from the first adhesive layer (3). The conductive coating (1) is a carbon microcrystalline film conductive coating (1) or a nickel-based conductive coating (1), and the thickness of the conductive coating (1) is 1~5μm. The conductive cloth layer (4) is a nickel-plated elastic conductive cloth or a gold-plated conductive cloth, and the thickness of the conductive cloth layer (4) is 0.02~0.5mm.

2. The flexible electromagnetic shielding composite structure for HOD steering wheels as described in claim 1, characterized in that: It also includes a release layer (6), which is located on the side of the second adhesive layer (5) away from the conductive cloth layer (4).

3. The flexible electromagnetic shielding composite structure for HOD steering wheels as described in claim 1, characterized in that: The TPU substrate (2) is a thermoplastic polyurethane film, and the thickness of the TPU substrate (2) is 0.01~2mm.

4. The flexible electromagnetic shielding composite structure for HOD steering wheels as described in claim 1, characterized in that: Both the first adhesive layer (3) and the second adhesive layer (5) are acrylic pressure-sensitive adhesives, and the thickness of the first adhesive layer (3) and the second adhesive layer (5) is 0.03~0.1mm.

5. The flexible electromagnetic shielding composite structure for HOD steering wheels as described in claim 1, characterized in that: It also includes a grounding guide structure connected to a nickel-plated elastic conductive cloth, wherein the grounding guide structure is made of metal wires fixed to the nickel-plated elastic conductive cloth in a V-shape or U-shape, and the grounding guide structure is connected to an external vehicle grounding system through a wire.

6. The flexible electromagnetic shielding composite structure for HOD steering wheels as described in claim 2, characterized in that: The release layer (6) is a polyester film, the release layer (6) is a textured release film, and the thickness of the release layer (6) is 0.025mm~0.075mm.

Images