Integrated front and rear wheel housings for a passenger car body

Abstract

The application discloses an integrated front and rear wheel cover of a car body, wherein the front wheel cover and the rear wheel cover both comprise a carbon fiber structure layer and a sound absorption layer arranged on the inner side of the carbon fiber structure layer; the carbon fiber structure layer is formed by molding a plurality of carbon fiber cloth layers after cutting and surface treatment; the sound absorption layer is formed by molding an inner mixed polyester fiber fabric layer, a middle polyethylene layer and an outer PET fiber fabric layer; the carbon fiber structure layer and the sound absorption layer are integrated by adhesion; and the mixed polyester fiber fabric layer of the sound absorption layer is attached to the surface of the carbon fiber structure layer. The application can improve the strength of the front and rear wheel covers, realize light weight, and effectively realize sound absorption and sound insulation.

Description

Technical Field

[0001] This invention relates to integrated front and rear wheel covers for automobile bodies, belonging to the field of automotive wheel covers. Background Technology

[0002] With the continuous development of the domestic automobile industry, automobiles have become a very common means of transportation. In recent years, noise reduction wheel covers have become a key development direction for many domestic automobile manufacturers. The earliest automobile wheel covers were made of metal stamping, and later they were changed to plastic wheel covers. However, wheel covers made of different plastic materials cannot guarantee the effect of noise reduction and the strength of the wheel covers is insufficient. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an integrated front and rear wheel arch cover for a car body, which can improve the strength of the front and rear wheel arch covers while achieving weight reduction. In addition, it can effectively reduce and isolate the noise generated by the friction between the tires and the ground to a certain extent.

[0004] The technical solution adopted in this invention is as follows:

[0005] The integrated front and rear wheel arches of the car body include a carbon fiber structural layer and a sound-absorbing layer set inside the carbon fiber structural layer. The carbon fiber structural layer is molded from multiple layers of carbon fiber cloth that have been cut and surface-treated. The sound-absorbing layer is molded from an inner layer of mixed polyester fiber fabric, a middle layer of polyethylene, and an outer layer of PET fiber fabric. The carbon fiber structural layer and the sound-absorbing layer are bonded together with an adhesive to form an integrated structure, and the mixed polyester fiber fabric layer of the sound-absorbing layer is attached to the surface of the carbon fiber structural layer.

[0006] Preferably, the surface treatment of the carbon fiber cloth includes the following steps:

[0007] Step 1: Extract the carbon fiber cloth with acetone for 24 hours and then dry it; then needle-punch the dried carbon fiber mesh, and then immerse the needle-punched carbon fiber mesh in a mixed solution of KClO3 and H2SO4 and heat it in a water bath for 50-60 minutes at a temperature of 88℃-90℃.

[0008] Step 2: After removing the carbon fiber cloth impregnated in Step 1, rinse it with distilled water and dry it. Then, immerse the dried carbon fiber cloth in an ethanol solution for 1-1.5 hours. The ethanol solution contains 3%-5% by mass of organosilane coupling agent. During impregnation, ultrasound is used to act on the impregnation solution to improve the treatment effect.

[0009] Step 3: After removing the carbon fiber cloth that has been impregnated in Step 2, rinse it with distilled water and dry it. Then, perform a second needle punching treatment on the carbon fiber cloth.

[0010] In a further preferred embodiment, in the mixed solution of KClO3 and H2SO4 in the first step of the surface treatment of carbon fiber cloth, the mass ratio of KClO3 to H2SO4 is 1:20-25.

[0011] A further preferred embodiment of the molding process for carbon fiber cloth includes the following steps:

[0012] Step 1: The surface-treated carbon fiber cloth is steam-heated to 180℃-190℃, and then the upper and lower surfaces of the carbon fiber cloth, which has been heated and cooled to 80℃-90℃, are coated with a mixed adhesive and subjected to ultrasonic treatment for 3 min-5 min.

[0013] Step 2: Lay multiple sheets of carbon fiber cloth coated with the mixed adhesive into the lower mold of the molding machine according to the required thickness. Then, press down the upper mold to close the mold with the lower mold. The machine is thermoformed under a pressure of 70T-80T and a heating temperature of 200℃-210℃. After forming, hold the pressure for 15s-30s, cool and demold. Then cut the cloth into specific sizes on the cutting equipment.

[0014] In a further preferred embodiment, the mixed adhesive is prepared by mixing epoxy resin, m-phenylenediamine, and polypropylene glycol diglycidyl ether in a mass ratio of 100:1:70.

[0015] In a further preferred embodiment, the blended polyester fiber fabric layer is a fabric obtained by knitting and needle-punching a mixture of polypropylene fiber monofilaments and PET fiber monofilaments.

[0016] Further optimization, the molding of the sound-absorbing layer includes the following steps:

[0017] Step 1: Lay the mixed polyester fiber fabric flat in the mold, then sprinkle a layer of PE powder evenly on the mixed polyester fiber fabric, and then lay the PET fiber fabric flat on the PE powder.

[0018] Step 2: After mold closing, the temperature is gradually increased and pressed for 10-15 minutes under a hot pressing pressure of 10MPa-12MPa, and then cooled and demolded to obtain the sound-absorbing layer composite material.

[0019] Step 3: Lay the sound-absorbing composite material into the lower mold of the molding machine, heat the lower mold to 105℃-110℃ and then close the mold. Then heat it under a pressure of 60T-65T to thermoform it. After molding, hold the pressure for 15s-20s and then cool and demold. Then cut it into specific sizes on the cutting equipment to obtain the sound-absorbing layer.

[0020] Further optimization involves the following steps in the molding process of the sound-absorbing layer: first, both the upper and lower molds are heated to 110℃-115℃ and held at that temperature for 3-5 minutes; then, the lower mold is heated to 165℃-170℃ and the upper mold is heated to 150℃-155℃.

[0021] Further optimization, the thermoforming temperature in step three of the sound-absorbing layer molding process is 145℃-155℃.

[0022] The beneficial effects of this invention are as follows:

[0023] (1) By treating the cut carbon fiber cloth with a mixed solution of KClO3 and H2SO4, the surface roughness of the carbon fiber can be increased, so that the carbon fiber cloth can be better bonded by the mixed adhesive; the carbon fiber cloth can be treated with an ethanol solution containing 3%-5% by mass of organosilane coupling agent to ensure the strength of the carbon fiber cloth.

[0024] (2) The material and structure of the sound-absorbing layer can effectively isolate and reduce the noise generated by the friction between the tire and the ground, that is, it has both sound absorption and sound insulation functions.

[0025] (3) The use of carbon fiber structural layer and sound absorption layer can effectively reduce wheel cover weight and improve wheel cover strength, thus achieving lightweighting. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the embodiments.

[0027] Example 1: This example is an integrated front and rear wheel arches for a car body. Both the front and rear wheel arches include a carbon fiber structural layer and a sound-absorbing layer disposed inside the carbon fiber structural layer. The carbon fiber structural layer is molded from multiple layers of carbon fiber cloth that have been cut and surface-treated. The sound-absorbing layer is molded from an inner layer of mixed polyester fiber fabric, a middle layer of polyethylene, and an outer layer of PET fiber fabric. The carbon fiber structural layer and the sound-absorbing layer are bonded together with an adhesive to form an integrated structure, and the mixed polyester fiber fabric layer of the sound-absorbing layer is attached to the surface of the carbon fiber structural layer.

[0028] In this embodiment, the surface treatment of the carbon fiber cloth includes the following steps:

[0029] Step 1: Extract the carbon fiber cloth with acetone for 24 hours and then dry it; then needle-punch the dried carbon fiber mesh, and then immerse the needle-punched carbon fiber mesh in a mixed solution of KClO3 and H2SO4 and heat it in a water bath for 50 minutes at a water bath temperature of 90℃.

[0030] Step 2: After removing the carbon fiber cloth impregnated in Step 1, rinse it with distilled water and dry it. Then, immerse the dried carbon fiber cloth in an ethanol solution for 1 hour. The ethanol solution contains 5% by mass of organosilane coupling agent. During impregnation, ultrasound is used to act on the impregnation solution to improve the treatment effect.

[0031] Step 3: After removing the carbon fiber cloth that has been impregnated in Step 2, rinse it with distilled water and dry it. Then, perform a second needle punching treatment on the carbon fiber cloth.

[0032] In this embodiment, in the mixed solution of KClO3 and H2SO4 in the first step of the surface treatment of carbon fiber cloth, the mass ratio of KClO3 to H2SO4 is 1:20.

[0033] In this embodiment, the compression molding of carbon fiber cloth includes the following steps:

[0034] Step 1: The surface-treated carbon fiber cloth is steam-heated to 180°C, and then the upper and lower surfaces of the carbon fiber cloth, which has been heated and cooled to 80°C, are coated with a mixed adhesive and subjected to ultrasonic treatment for 5 minutes.

[0035] Step 2: Lay multiple sheets of carbon fiber cloth coated with the mixed adhesive into the lower mold of the molding machine according to the required thickness. Then, the upper mold presses down and closes with the lower mold. The mixture is thermoformed under a pressure of 70T and a heating temperature of 210℃. After forming, the pressure is held for 15 seconds and then cooled and demolded. Finally, it is cut into specific sizes on a cutting device.

[0036] In this embodiment, the mixed adhesive is prepared by mixing epoxy resin, m-phenylenediamine, and polypropylene glycol diglycidyl ether in a mass ratio of 100:1:70.

[0037] In this embodiment, the mixed polyester fiber fabric layer is a fabric obtained by knitting and needle-punching a mixture of polypropylene fiber monofilaments and PET fiber monofilaments.

[0038] In this embodiment, the molding of the sound-absorbing layer includes the following steps:

[0039] Step 1: Lay the mixed polyester fiber fabric flat in the mold, then sprinkle a layer of PE powder evenly on the mixed polyester fiber fabric, and then lay the PET fiber fabric flat on the PE powder.

[0040] Step 2: After mold closing, under a hot pressing pressure of 10MPa, both the upper and lower molds are first heated to 115℃ and held at that temperature for 3 minutes. Then, the lower mold is heated to 165℃ and the upper mold to 150℃. After the heating is completed, the mold is pressed for 10 minutes and then cooled and demolded to obtain the sound-absorbing layer composite material. During the gradual heating process, the PE powder in the middle melts first due to its lower melting point to form a polyethylene layer, which plays a role in shaping after cooling. After the lower mold is heated to the molding temperature, the polypropylene fiber in the polypropylene fiber monofilament and PET fiber monofilament has a lower melting point than the PET fiber. During the heating and molding process, the polypropylene fiber monofilament melts and also plays a role in shaping after cooling.

[0041] Step 3: Lay the sound-absorbing composite material into the lower mold of the molding machine, heat the lower mold to 105℃ to soften the material, and then close the mold. Then heat it under a pressure of 60T to thermoform it. After molding, hold the pressure for 20 seconds, cool and demold, and then cut it into specific sizes on a cutting machine to obtain the sound-absorbing layer.

[0042] In this embodiment, the thermoforming temperature in step three of the sound-absorbing layer molding process is 155°C.

[0043] Example 2: This example is an integrated front and rear wheel arches for a car body. Both the front and rear wheel arches include a carbon fiber structural layer and a sound-absorbing layer disposed inside the carbon fiber structural layer. The carbon fiber structural layer is molded from multiple layers of carbon fiber cloth that have been cut and surface-treated. The sound-absorbing layer is molded from an inner layer of mixed polyester fiber fabric, a middle layer of polyethylene, and an outer layer of PET fiber fabric. The carbon fiber structural layer and the sound-absorbing layer are bonded together with an adhesive to form an integrated structure, and the mixed polyester fiber fabric layer of the sound-absorbing layer is attached to the surface of the carbon fiber structural layer.

[0044] In this embodiment, the surface treatment of the carbon fiber cloth includes the following steps:

[0045] Step 1: Extract the carbon fiber cloth with acetone for 24 hours and then dry it; then needle-punch the dried carbon fiber mesh, and then immerse the needle-punched carbon fiber mesh in a mixed solution of KClO3 and H2SO4 and heat it in a water bath for 60 minutes at a water bath temperature of 88℃.

[0046] Step 2: After removing the carbon fiber cloth impregnated in Step 1, rinse it with distilled water and dry it. Then, immerse the dried carbon fiber cloth in an ethanol solution for 1.5 hours. The ethanol solution contains 3% by mass of organosilane coupling agent. During impregnation, ultrasound is used to act on the impregnation solution to improve the treatment effect.

[0047] Step 3: After removing the carbon fiber cloth that has been impregnated in Step 2, rinse it with distilled water and dry it. Then, perform a second needle punching treatment on the carbon fiber cloth.

[0048] In this embodiment, in the mixed solution of KClO3 and H2SO4 in the first step of the surface treatment of carbon fiber cloth, the mass ratio of KClO3 to H2SO4 is 1:25.

[0049] In this embodiment, the compression molding of carbon fiber cloth includes the following steps:

[0050] Step 1: The surface-treated carbon fiber cloth is steam-heated to 190°C, and then the upper and lower surfaces of the carbon fiber cloth, which has been heated and cooled to 90°C, are coated with a mixed adhesive and subjected to ultrasonic treatment for 3 minutes.

[0051] Step 2: Lay multiple sheets of carbon fiber cloth coated with the mixed adhesive into the lower mold of the molding machine according to the required thickness. Then, the upper mold presses down and closes with the lower mold. The mixture is thermoformed under a pressure of 80T and a heating temperature of 200℃. After forming, the pressure is held for 30 seconds and then cooled and demolded. Finally, it is cut into specific sizes on a cutting device.

[0052] In this embodiment, the mixed adhesive is prepared by mixing epoxy resin, m-phenylenediamine, and polypropylene glycol diglycidyl ether in a mass ratio of 100:1:70.

[0053] In this embodiment, the mixed polyester fiber fabric layer is a fabric obtained by knitting and needle-punching a mixture of polypropylene fiber monofilaments and PET fiber monofilaments.

[0054] In this embodiment, the molding of the sound-absorbing layer includes the following steps:

[0055] Step 1: Lay the mixed polyester fiber fabric flat in the mold, then sprinkle a layer of PE powder evenly on the mixed polyester fiber fabric, and then lay the PET fiber fabric flat on the PE powder.

[0056] Step 2: After mold closing, under a hot pressing pressure of 12MPa, both the upper and lower molds are first heated to 110℃ and held for 5 minutes. Then, the lower mold is heated to 170℃ and the upper mold to 155℃. After the heating is completed, the mold is pressed for 15 minutes and then cooled and demolded to obtain the sound-absorbing layer composite material. During the gradual heating process, the PE powder in the middle melts first due to its lower melting point to form a polyethylene layer, which plays a role in shaping after cooling. After the lower mold is heated to the molding temperature, the polypropylene fiber in the polypropylene fiber monofilament and PET fiber monofilament has a lower melting point than the PET fiber. During the heating and molding process, the polypropylene fiber monofilament melts and also plays a role in shaping after cooling.

[0057] Step 3: Lay the sound-absorbing composite material into the lower mold of the molding machine, heat the lower mold to 110℃ to soften the material, and then close the mold. Then heat it under a pressure of 65T to thermoform it. After molding, hold the pressure for 15 seconds, cool and demold, and then cut it into specific sizes on a cutting machine to obtain the sound-absorbing layer.

[0058] In this embodiment, the thermoforming temperature in step three of the sound-absorbing layer molding process is 145°C.

[0059] Example 3: This example is an integrated front and rear wheel arches for a car body. Both the front and rear wheel arches include a carbon fiber structural layer and a sound-absorbing layer disposed inside the carbon fiber structural layer. The carbon fiber structural layer is molded from multiple layers of carbon fiber cloth that have been cut and surface-treated. The sound-absorbing layer is molded from an inner layer of mixed polyester fiber fabric, a middle layer of polyethylene, and an outer layer of PET fiber fabric. The carbon fiber structural layer and the sound-absorbing layer are bonded together with an adhesive to form an integrated structure, and the mixed polyester fiber fabric layer of the sound-absorbing layer is attached to the surface of the carbon fiber structural layer.

[0060] In this embodiment, the surface treatment of the carbon fiber cloth includes the following steps:

[0061] Step 1: Extract the carbon fiber cloth with acetone for 24 hours and then dry it; then needle-punch the dried carbon fiber mesh, and then immerse the needle-punched carbon fiber mesh in a mixed solution of KClO3 and H2SO4 and heat it in a water bath for 55 minutes at a water bath temperature of 89℃.

[0062] Step 2: After removing the carbon fiber cloth impregnated in Step 1, rinse it with distilled water and dry it. Then, immerse the dried carbon fiber cloth in an ethanol solution for 1.2 hours. The ethanol solution contains 4% by mass of organosilane coupling agent. During impregnation, ultrasound is used to act on the impregnation solution to improve the treatment effect.

[0063] Step 3: After removing the carbon fiber cloth that has been impregnated in Step 2, rinse it with distilled water and dry it. Then, perform a second needle punching treatment on the carbon fiber cloth.

[0064] In this embodiment, in the mixed solution of KClO3 and H2SO4 in the first step of the surface treatment of carbon fiber cloth, the mass ratio of KClO3 to H2SO4 is 1:23.

[0065] In this embodiment, the compression molding of carbon fiber cloth includes the following steps:

[0066] Step 1: The surface-treated carbon fiber cloth is steam-heated to 185°C, and then the upper and lower surfaces of the carbon fiber cloth, which has been heated and cooled to 85°C, are coated with a mixed adhesive and subjected to ultrasonic treatment for 4 minutes.

[0067] Step 2: Lay multiple sheets of carbon fiber cloth coated with the mixed adhesive into the lower mold of the molding machine according to the required thickness. Then, the upper mold presses down and closes with the lower mold. The mixture is thermoformed under a pressure of 75T and a heating temperature of 205℃. After forming, the pressure is held for 25 seconds and then cooled and demolded. Finally, it is cut into specific sizes on a cutting device.

[0068] In this embodiment, the mixed adhesive is prepared by mixing epoxy resin, m-phenylenediamine, and polypropylene glycol diglycidyl ether in a mass ratio of 100:1:70.

[0069] In this embodiment, the mixed polyester fiber fabric layer is a fabric obtained by knitting and needle-punching a mixture of polypropylene fiber monofilaments and PET fiber monofilaments.

[0070] In this embodiment, the molding of the sound-absorbing layer includes the following steps:

[0071] Step 1: Lay the mixed polyester fiber fabric flat in the mold, then sprinkle a layer of PE powder evenly on the mixed polyester fiber fabric, and then lay the PET fiber fabric flat on the PE powder.

[0072] Step 2: After mold closing, under a hot pressing pressure of 11MPa, both the upper and lower molds are first heated to 112℃ and held at that temperature for 4 minutes. Then, the lower mold is heated to 168℃ and the upper mold to 152℃. After the heating is completed, the mold is pressed for 12 minutes and then cooled and demolded to obtain the sound-absorbing layer composite material. During the gradual heating process, the PE powder in the middle melts first due to its lower melting point to form a polyethylene layer, which plays a role in shaping after cooling. After the lower mold is heated to the molding temperature, the polypropylene fiber in the polypropylene fiber monofilament and PET fiber monofilament has a lower melting point than the PET fiber. During the heating and molding process, the polypropylene fiber monofilament melts and also plays a role in shaping after cooling.

[0073] Step 3: Lay the sound-absorbing composite material into the lower mold of the molding machine, heat the lower mold to 108℃ to soften the material, and then close the mold. Then heat it under a pressure of 63T to thermoform it. After molding, hold the pressure for 18s, cool and demold, and then cut it into specific sizes on a cutting machine to obtain the sound-absorbing layer.

[0074] In this embodiment, the thermoforming temperature in step three of the sound-absorbing layer molding process is 150°C.

[0075] This invention increases the surface roughness of carbon fiber by treating the cut carbon fiber cloth with a mixed solution of KClO3 and H2SO4, which allows for better bonding between the carbon fiber pieces using the mixed adhesive. Treatment of the carbon fiber cloth with an ethanol solution containing 3%-5% by mass of organosilane coupling agent ensures its strength. The material and structure of the sound-absorbing layer effectively isolate and reduce noise generated by tire-ground friction, thus providing both sound absorption and sound insulation. The bonding of the carbon fiber structural layer and the sound-absorbing layer effectively reduces the wheel cover's weight while increasing its strength, achieving lightweight design.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An integrated front and rear wheel arch cover for a car body, characterized in that: Both the front and rear wheel arches include a carbon fiber structural layer and a sound-absorbing layer disposed inside the carbon fiber structural layer. The carbon fiber structural layer is molded from multiple layers of carbon fiber cloth that have been cut and surface-treated. The sound-absorbing layer is molded from an inner layer of mixed polyester fiber fabric, a middle layer of polyethylene, and an outer layer of PET fiber fabric. The carbon fiber structural layer and the sound-absorbing layer are bonded together with an adhesive to form an integral structure, and the mixed polyester fiber fabric layer of the sound-absorbing layer is attached to the surface of the carbon fiber structural layer. The compression molding of the carbon fiber cloth includes the following steps: Step 1: The surface-treated carbon fiber cloth is steam-heated to 180℃-190℃, and then the upper and lower surfaces of the carbon fiber cloth, which has been cooled to 80℃-90℃, are coated with a mixed adhesive and ultrasonically treated for 3-5 minutes. The mixed adhesive is prepared by mixing epoxy resin, m-phenylenediamine, and polypropylene glycol diglycidyl ether in a mass ratio of 100:1:

70. Step 2: Lay multiple sheets of carbon fiber cloth coated with the mixed adhesive into the lower mold of the molding machine according to the required thickness. Then, press down the upper mold to close the mold with the lower mold. The machine is thermoformed under a pressure of 70T-80T and a heating temperature of 200℃-210℃. After forming, hold the pressure for 15s-30s, cool and demold. Then cut the cloth into specific sizes on the cutting equipment.

2. The integrated front and rear wheel arches of a car body according to claim 1, characterized in that, The surface treatment of the carbon fiber cloth includes the following steps: Step 1: Extract the carbon fiber cloth with acetone for 24 hours and then dry it; then perform needle punching on the dried carbon fiber cloth, and then immerse the needle-punched carbon fiber cloth in a mixed solution of KClO3 and H2SO4 and heat it in a water bath for 50-60 minutes at a water bath temperature of 88℃-90℃. Step 2: After removing the carbon fiber cloth impregnated in Step 1, rinse it with distilled water and dry it. Then, immerse the dried carbon fiber cloth in an ethanol solution for 1-1.5 hours. The ethanol solution contains 3%-5% by mass of organosilane coupling agent. Ultrasonic treatment is used on the impregnation solution during impregnation to improve the treatment effect. Step 3: After removing the carbon fiber cloth that has been impregnated in Step 2, rinse it with distilled water and dry it. Then, perform a second needle punching treatment on the carbon fiber cloth.

3. The integrated front and rear wheel arches of a car body according to claim 2, characterized in that, In the first step of the surface treatment of the carbon fiber cloth, the mass ratio of KClO3 to H2SO4 in the mixed solution is 1:20~25.

4. The integrated front and rear wheel arches of a car body according to claim 1, characterized in that, The mixed polyester fiber fabric layer is a fabric obtained by knitting and needle-punching a mixture of polypropylene fiber monofilaments and PET fiber monofilaments.

5. The integrated front and rear wheel arches of a passenger car body according to claim 1 or 4, characterized in that, The molding process of the sound-absorbing layer includes the following steps: Step 1: Lay the mixed polyester fiber fabric flat in the mold, then sprinkle a layer of PE powder evenly on the mixed polyester fiber fabric, and then lay the PET fiber fabric flat on the PE powder. Step 2: After mold closing, the temperature is gradually increased and pressed for 10-15 minutes under a hot pressing pressure of 10MPa-12MPa, and then cooled and demolded to obtain the sound-absorbing layer composite material. Step 3: Lay the sound-absorbing composite material into the lower mold of the molding machine, heat the lower mold to 105℃-110℃ and then close the mold. Then heat it under a pressure of 60T-65T to thermoform it. After molding, hold the pressure for 15s-20s and then cool and demold. Then cut it into specific sizes on the cutting equipment to obtain the sound-absorbing layer.

6. The integrated front and rear wheel arches of a passenger car body according to claim 5, characterized in that, The specific steps for gradually increasing the temperature in step two of the molding process of the sound-absorbing layer are as follows: first, both the upper and lower molds are heated to 110℃-115℃ and then kept at that temperature for 3-5 minutes. Then, the lower mold is heated to 165℃-170℃ and the upper mold is heated to 150℃-155℃.

7. The integrated front and rear wheel arches of a car body according to claim 5, characterized in that, The thermoforming temperature in step three of the molding process of the sound-absorbing layer is 145℃-155℃.