A metal-resin composite automotive front engine hood and its manufacturing method

Abstract

The present invention relates to the field of automobile hoods, in particular to a metal-resin composite automobile front hood and a preparation method thereof, including a continuous carbon fiber composite outer panel. Upper peripheral reinforcing ribs, right peripheral reinforcing ribs, lower peripheral reinforcing ribs, and left peripheral reinforcing ribs are respectively fixedly arranged at the inner edges of the continuous carbon fiber composite outer panel. The traditional structure of a metal outer panel and an inner panel is abandoned and replaced by a resin-based composite outer panel and metal internal reinforcing ribs. The outer panel is made of a continuous fiber thermoplastic composite material, and the internal reinforcing ribs are made of a metal material. The outer panel and the internal reinforcing ribs are integrally formed by a non-mechanical connection method. The present invention solves the problems of high material cost and complex process.

Description

Technical Field

[0001] The present invention relates to the field of automobile hoods, and in particular to a metal-resin composite automobile front hood and a preparation method thereof. Background Art

[0002] Automobile lightweighting means, on the premise of ensuring the strength and safety performance of the automobile, reducing the curb weight of the automobile as much as possible, thereby improving the power performance of the automobile, reducing fuel consumption, and reducing exhaust pollution. Experiments have proved that when the automobile mass is reduced by half, the fuel consumption will also be reduced by nearly half. Due to the needs of environmental protection and energy conservation, automobile lightweighting has become a trend in the development of the world's automobiles. The main ways of automobile lightweighting are to optimize the automobile body structure and optimize the use of materials. Among them, the use of lightweight and high-strength materials is considered to be one of the most effective methods. For example, high-strength steel plates, aluminum alloys, magnesium alloys, carbon fiber composite materials, etc. have been applied to automobile manufacturing.

[0003] The automobile hood is an important part of the automobile body. The traditional automobile hood generally consists of two parts, an outer panel and an inner panel, which are formed by stamping thin steel plates and then welded. Since this kind of hood uses steel, it is not conducive to lightweighting. And because the strength and rigidity of steel are too large, after a collision, it cannot effectively absorb energy and cannot meet the requirements of collision safety performance and pedestrian protection. Composite materials have excellent properties such as low density, high specific strength, and high specific modulus. Therefore, using composite materials for the design of the hood conforms to the trend of future automobile development. However, using only resin-based composite materials to make the entire hood has many problems. For example, the patent CN109501870A proposes a preparation method for a carbon fiber composite hood with an inner and outer panel plus a sandwich structure. Although the carbon fiber composite material can meet the design requirements, the material itself is very expensive, and it cannot save costs. Moreover, the complex structure makes the molding process difficult and batch production cannot be achieved. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] In view of this, one of the purposes of the present invention is to provide a metal-resin composite hood, which not only solves the disadvantages of steel hoods such as high rigidity, high brittleness, low energy absorption efficiency, and inability to meet collision safety, but also solves the problems of high price and complex structure caused by using a single continuous carbon fiber composite material, which makes the molding process difficult and batch production cannot be achieved.

[0006] (2) Technical Solutions

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A metal-resin composite automotive front hood, including a continuous carbon fiber composite outer panel. Inner edges of the continuous carbon fiber composite outer panel are respectively fixedly provided with an upper peripheral reinforcing rib, a right peripheral reinforcing rib, a lower peripheral reinforcing rib, and a left peripheral reinforcing rib. Below the upper peripheral reinforcing rib inside the continuous carbon fiber composite outer panel, a first horizontal rib is fixedly provided. On both sides of the first horizontal rib, near one end of the upper peripheral reinforcing rib, a first buffer block fixing groove and a second buffer block fixing groove are respectively fixedly provided. Below the first horizontal rib, a second horizontal rib is fixedly provided. Below the second horizontal rib, a third horizontal rib is fixedly provided. Near the center side of the lower part of the right peripheral reinforcing rib and the left peripheral reinforcing rib, a second inclined rib and a first inclined rib are respectively fixedly provided. The other ends of the second inclined rib and the first inclined rib are respectively fixedly connected to both sides of the upper peripheral reinforcing rib. The lower ends of the left peripheral reinforcing rib and the right peripheral reinforcing rib are both arranged in an "A" shape structure. On both sides of the center of the upper peripheral reinforcing rib, a first vertical rib and a second vertical rib are respectively fixedly provided. The lower ends of the first vertical rib and the second vertical rib are respectively fixedly connected to both sides of the center of the lower peripheral reinforcing rib. Above the first vertical rib and the second vertical rib, a center lock hole is fixedly provided. The intersection point of the first inclined rib and the second inclined rib is located within the intersection area of the first vertical rib, the second vertical rib, the second horizontal rib, and the third horizontal rib.

[0008] Preferably, the thickness of the continuous carbon fiber composite outer panel is 2 mm.

[0009] Preferably, on both sides of the lower peripheral reinforcing rib, a right side hinge and a left side hinge are respectively fixedly provided.

[0010] Preferably, the continuous carbon fiber composite outer panel is made of a thermoplastic resin with a viscosity of 200 - 6000 Pa·s.

[0011] A preparation method for a metal-resin composite automotive front hood includes the following steps:

[0012] S1. Use blanking to punch out the approximate contour of the periphery of the internal reinforcing rib, and then use wire cutting to cut out the internal structure. The buffer block and the center lock hole are processed separately and then welded on.

[0013] S2. Perform surface roughening treatment on the internal reinforcing rib.

[0014] S3. Stack the outer panel and the internal reinforcing rib and place them in a forming mold. The thermoplastic resin prepreg melts due to the temperature, and adheres to the internal metal reinforcing rib due to the resin viscosity, and cools and solidifies in the mold to form an integral structure.

[0015] Preferably, the thermoplastic resin in step 3 may include one or several of polyphenylene sulfide, polybutylene terephthalate, and polyamide.

[0016] Preferably, the melting point of the resin is above 260 °C.

[0017] Beneficial effects

[0018] The metal-resin composite engine hood of the present invention and its preparation method have the following beneficial effects:

[0019] 1. Compared with the traditional steel engine hood, the outer panel made of resin-based composite material can meet the automotive collision safety performance, protect pedestrians. Also, due to the low density of the carbon fiber composite material, high specific strength and specific modulus, it is beneficial to the lightweight of the vehicle.

[0020] 2. Compared with the traditional composite engine hood, the present invention abandons the design of the traditional outer panel, inner panel and honeycomb core sandwich structure, and adopts the structure of the outer panel and internal reinforcing ribs. The outer panel uses continuous carbon fiber composite material, and the internal reinforcing ribs use aluminum alloy. For the traditional carbon fiber engine hood, both the outer panel and the inner panel are made of carbon fiber material, which makes the material cost very expensive, and the complex structure will cause great difficulty in the forming process and cannot achieve mass production. Changing the inner panel to a metal reinforcing rib structure can greatly reduce the material and process costs. By reasonably designing the reinforcing rib structure, on the premise of meeting the performance requirements, the overall structure can be further lightened, and it is also convenient for the recycling of materials.

[0021] 3. It provides a connection technology for one-time forming of metal and resin, avoiding the traditional adhesive bonding method and mechanical connection methods using screws and rivets, and the connection technology is more convenient. Description of the drawings

[0022] Figure 1 It is a top view structural schematic diagram of the present invention;

[0023] Figure 2 It is a connection structural schematic diagram of the upper peripheral reinforcing rib, right peripheral reinforcing rib, lower peripheral reinforcing rib and left peripheral reinforcing rib of the present invention;

[0024] Figure 3 It is a connection structural schematic diagram of the first vertical rib, central lock hole and second vertical rib of the present invention;

[0025] Figure 4 It is Figure 2 The enlarged view of A in

[0026] Among them, 1. Continuous carbon fiber composite material outer panel; 2. Upper peripheral reinforcing rib; 3. Buffer block fixing groove 1; 4. First horizontal rib; 5. First vertical rib; 6. Central lock hole; 7. Second vertical rib; 8. Buffer block fixing groove 2; 9. First inclined rib; 10. Second horizontal rib; 11. Right peripheral reinforcing rib; 12. Third horizontal rib; 13. Second inclined rib; 14. Right side hinge; 15. Lower peripheral reinforcing rib; 16. Left side hinge; 17. Left peripheral reinforcing rib. Detailed implementation manners

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to 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 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.

[0028] Embodiment:

[0029] Such as Figures 1-4As shown in the figure, an embodiment of the present invention provides a metal resin composite automotive front engine hood, which includes a continuous carbon fiber composite outer panel 1. Upper peripheral stiffeners 2, right peripheral stiffeners 11, lower peripheral stiffeners 15, and left peripheral stiffeners 17 are respectively fixedly arranged at the inner edges of the continuous carbon fiber composite outer panel 1, which can effectively improve the modal and structural stiffness of the engine hood. Twelve small ribs connected to the upper peripheral stiffener 2 are arranged above the stiffener 2. On the one hand, they are used to enhance the lateral stiffness of the engine hood, and on the other hand, they can assist in increasing the overall modal of the engine hood. A first horizontal rib 4 is fixedly arranged on the lower side of the upper peripheral stiffener 2 inside the continuous carbon fiber composite outer panel 1. Buffer block fixing grooves 1 and 2, buffer block fixing grooves 8 are respectively fixedly arranged on both sides of the first horizontal rib 4 near one end of the upper peripheral stiffener 2. The buffer block fixing grooves are used to fix the buffer blocks on the automotive engine hood. A second horizontal rib 10 is fixedly arranged on the lower side of the first horizontal rib 4, and a third horizontal rib 12 is fixedly arranged on the lower side of the second horizontal rib 10. The above three horizontal ribs are arranged to meet the two torsional stiffness requirements of the engine hood. Oblique ribs 2 and 1 are respectively fixedly arranged on the lower parts of the right peripheral stiffener 11 and the left peripheral stiffener 17 near the center side of the continuous carbon fiber composite outer panel 1. For an engine hood with a large volume and a thin wall thickness, if too many flat surfaces are retained, resonance will occur due to insufficient stiffness, posing a great potential safety hazard. Therefore, two oblique ribs are arranged to improve the modal of the engine hood. The other ends of the oblique rib 2 and the oblique rib 1 are respectively fixedly connected to both sides of the upper peripheral stiffener 2. The lower ends of the left peripheral stiffener 17 and the right peripheral stiffener 11 are both arranged in an "A" - shaped structure. At the corner points of the engine hood, if the connection of the stiffeners directly uses a right - angle transition, the connection area between the outer panel of the engine hood and the stiffeners at the corner points will be too small, making it difficult to pass the corner point stiffness. The present invention designs an inverted "A" - shaped transition at the corner points to increase the contact area between the outer panel corner points of the engine hood and the internal stiffeners to increase the stiffness at the corner points. Vertical ribs 1 and 5, vertical ribs 2 and 7 are respectively fixedly arranged on both sides of the center of the upper peripheral stiffener 2. The lower ends of the vertical rib 1 and the vertical rib 2 are respectively fixedly connected to both sides of the center of the lower peripheral stiffener 15. A center lock hole 6 is fixedly arranged on the upper side between the vertical rib 1 and the vertical rib 2 to meet the functional installation requirements of the engine hood. The intersection point of the oblique rib 1 and the oblique rib 2 is located within the intersection area of the vertical rib 1, the vertical rib 2, the second horizontal rib 10, and the third horizontal rib 12.

[0030] The thickness of the continuous carbon fiber composite outer panel 1 is 2 mm.

[0031] Right - hand side hinges 14 and left - hand side hinges 16 are respectively fixedly arranged on both sides of the lower peripheral stiffener 15.

[0032] The continuous carbon fiber composite outer panel 1 is made of a thermoplastic resin material with a viscosity of 200 - 6000 Pa·s.

[0033] A preparation method of a metal-resin composite automotive front engine hood, comprising the following steps:

[0034] S1. Punch out the approximate contour of the periphery of the internal reinforcing rib, and then cut out the internal structure by wire cutting. The buffer block and the central lock hole are processed separately and then welded on;

[0035] S2. Perform roughening treatment on the surface of the internal reinforcing rib;

[0036] S3. Stack the outer panel and the internal reinforcing rib and place them in a forming mold. The thermoplastic resin prepreg melts due to the temperature, and adheres to the internal metal reinforcing rib due to the viscosity of the resin, and cools and solidifies in the mold to form a single body.

[0037] The thermoplastic resin in step 3 may include one or more of polyphenylene sulfide, polybutylene terephthalate, and polyamide.

[0038] The melting point of the resin is above 260 °C.

[0039] The above-mentioned metal-resin composite engine hood abandons the traditional structure of the outer panel and the inner panel, and instead uses the outer panel and the reinforcing rib. It can not only fully meet the requirements of the outer panel composite material for collision safety and pedestrian protection, but also solve the high cost brought by using a single carbon fiber composite material to make the engine hood, and the designed structure is complex, which brings many difficulties to the forming process. The density of the carbon fiber composite material of the outer panel and the aluminum alloy of the reinforcing rib is very small, which can fully meet the requirements of automotive lightweight. On top of this, the present invention provides a connection method in which the outer panel and the reinforcing rib are dissimilar materials. This connection method can be formed in one step, the process flow is simple, and it is more conducive to popularization.

[0040] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal-resin composite automotive front hood, comprising a continuous carbon fiber composite outer panel (1), characterized in that: Inside the inner edges of the continuous carbon fiber composite material outer plate (1), an upper peripheral reinforcing rib (2), a right peripheral reinforcing rib (11), a lower peripheral reinforcing rib (15), and a left peripheral reinforcing rib (17) are respectively fixedly arranged. Below the upper peripheral reinforcing rib (2) inside the continuous carbon fiber composite material outer plate (1), a first horizontal rib (4) is fixedly arranged. On both sides of the first horizontal rib (4), a first buffer block fixing groove (3) and a second buffer block fixing groove (8) are respectively fixedly arranged at both ends close to the upper peripheral reinforcing rib (2). Below the first horizontal rib (4), a second horizontal rib (10) is fixedly arranged. Below the second horizontal rib (10), a third horizontal rib (12) is fixedly arranged. On the lower part of the right peripheral reinforcing rib (11) and the left peripheral reinforcing rib (17) close to the center side of the continuous carbon fiber composite material outer plate (1), a second inclined rib (13) and a first inclined rib (9) are respectively fixedly arranged. The other ends of the second inclined rib (13) and the first inclined rib (9) are respectively fixedly connected to both sides of the upper peripheral reinforcing rib (2). The lower ends of the left peripheral reinforcing rib (17) and the right peripheral reinforcing rib (11) are both set in an "A" - shaped structure. On both sides of the center of the upper peripheral reinforcing rib (2), a first vertical rib (5) and a second vertical rib (7) are respectively fixedly arranged. The lower ends of the first vertical rib (5) and the second vertical rib (7) are respectively fixedly connected to both sides of the center of the lower peripheral reinforcing rib (15). Above the first vertical rib (5) and the second vertical rib (7), a center lock hole (6) is fixedly arranged. The intersection point of the first inclined rib (9) and the second inclined rib (13) is located within the intersection area of the first vertical rib (5), the second vertical rib (7), the second horizontal rib (10), and the third horizontal rib (12); A preparation method of a metal - resin composite automobile front engine hood, characterized in that it comprises the following steps: S1. Use blanking to punch out the general contour of the periphery of the internal reinforcing ribs, and then use wire cutting to cut out the internal structure. The buffer blocks and the center lock hole are processed separately and then welded on; S2. Carry out surface roughening treatment on the internal reinforcing ribs; S3. Stack the outer plate and the internal reinforcing ribs and put them into a forming mold. Due to the temperature, the thermoplastic resin prepreg melts, and due to the viscosity of the resin, it adheres to the internal metal reinforcing ribs and cools and solidifies in the mold to form a whole; 2. The metal resin composite automotive front hood according to claim 1, wherein: The thickness of the continuous carbon fiber composite material outer plate (1) is 2 mm.

3. A metal-resin composite automotive front engine hood according to claim 1, characterized in that: On both sides of the lower peripheral reinforcing rib (15), a right - hand side hinge (14) and a left - hand side hinge (16) are respectively fixedly arranged.

4. A metal resin composite automotive front engine hood according to claim 1, characterized in that: The continuous carbon fiber composite material outer plate (1) is made of a thermoplastic resin with a viscosity of 200 - 6000 Pa·s.

5. A metal resin composite automotive front engine hood according to claim 1, characterized in that: The thermoplastic resin in step 3 may include one or several of polyphenylene sulfide, polybutylene terephthalate, and polyamide.

6. A metal-resin composite automotive front hood according to claim 1, characterized in that: The melting point of the resin is above 260 °C.

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