Composite material light-weight automobile seat cross beam structure and preparation method thereof

Abstract

The invention belongs to the technical field of automobile structures, and provides a composite material lightweight automobile seat beam structure and a preparation method thereof. The cross beam takes glass fiber as a main body material, and carbon fiber is mixed in a local area to enhance modulus. The cross beam structurally comprises a middle-section cross beam, a transition section and a convex structure, the convex structure is slightly higher than the middle-section cross beam, and the convex structure and an inner groove opening in the middle of the cross beam form an asymmetric bow-shaped structure which is low in the middle and high on the two sides. A first side plate and a second side plate are arranged on the two sides of the cross beam, and connecting edges extending outwards are arranged on the cross beam and fixed to the front floor of the automobile in a glued mode. Reinforcing ribs are arranged on the back face of the beam, and the overall mechanical property of the beam is enhanced. The cross beam adopts an integrated mould pressing injection molding process, so that the welding defect of a traditional metal cross beam is avoided, and the manufacturing cost and time are reduced.

Description

Technical Field

[0001] The present invention belongs to the field of automobile parts design and preparation, and specifically relates to a composite material lightweight automobile seat crossbeam structure and a preparation method thereof. Background Art

[0002] In the modern automobile industry, the seat crossbeam is a key structural component that supports seats and ensures the safety of passengers. Its design and material selection have a direct impact on the overall performance of the car. The seat crossbeam not only needs to provide a stable installation base for the seat and its accessories, but also plays an important role in transmitting and dispersing the impact force in a side collision. Therefore, the seat crossbeam must have sufficient rigidity and strength, and at the same time, it must meet the development trend of lightweight vehicles.

[0003] Traditional seat beams are mostly made of metal materials, such as high-strength steel, and are made by cold stamping or welding. However, due to their high density, these metal beams are heavy overall, which is not conducive to lightweighting of the car. In addition, metal beams are often designed with equal width in structure, which limits the possibility of optimizing the design according to the stress conditions in specific areas. With the increasing requirements for automobile safety performance, it is usually necessary to add reinforcements or brackets at both ends or key areas of the beam, which not only increases the weight of the beam, but also increases the complexity and cost of manufacturing.

[0004] To solve the above problems, composite materials are used to manufacture seat beams. Composite materials have higher specific strength and specific stiffness than traditional metal materials, and can provide better design flexibility, thereby achieving structural optimization. In addition, the molding process of composite materials, such as compression molding and injection molding, can achieve integrated molding of complex shapes, further improving structural efficiency and production efficiency. At the same time, a series of issues need to be considered when using composite materials, such as the need to reasonably select the direction and sequence of composite material plies, and control the molding process of composite materials, especially the parameters of compression molding and injection molding. In addition, the connection and assembly methods of composite material beams also need to be redesigned to ensure compatibility and reliability with other metal structural parts of the car. Summary of the invention

[0005] The purpose of the present invention is to provide a composite lightweight automobile seat crossbeam structure and a preparation method thereof, which can simplify the preparation method of the automobile seat crossbeam and achieve lightweight parts, thereby meeting the safety performance requirements of the automobile seat crossbeam.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A composite lightweight automobile seat crossbeam structure comprises an automobile seat crossbeam body, wherein the crossbeam body is mounted on the front floor of the automobile, and the crossbeam body is respectively glued and fixed to the center channel and the inner door sill of the automobile on both sides in the width direction of the automobile body.

[0008] The crossbeam body is divided into three parts in the length direction, namely the middle crossbeam, the transition section and the protruding structure. The transition sections and the protruding structures on both sides of the crossbeam body are mirror-symmetrical structures to provide a unified and coordinated structural layout.

[0009] The transition section is connected to the middle cross beam and the protruding structure; the transition section is designed to be inclined and has a certain inclination angle, so as to form a smooth transition from the middle cross beam to the protruding structure.

[0010] The protruding structure is arranged along the length direction of the cross beam, that is, extends along the width direction of the vehicle body. The vehicle seat is fixedly mounted on the mounting surface of the protruding structure and connected with the cross beam body to form a whole.

[0011] The cross beam body is provided with a first side plate and a second side plate on both sides in the width direction, one side of the first side plate and the second side plate is connected to the top plate of the middle cross beam, and the other sides are provided with connecting edges extending outwards. The connecting edges are parallel to the front floor of the car, and the cross beam body is glued and fixed to the front floor of the car through the connecting edges.

[0012] Optionally, the middle section structure formed by the top plate, inner groove opening and two side plates of the middle section cross beam, that is, the cross section of the cross beam body along the width direction presents a "bow"-shaped structure, realizing continuous bending deformation.

[0013] Optionally, an inner groove opening is provided in the middle of the beam body, and the inner groove opening extends along the length direction of the beam body and passes through the middle beam and the transition section; the cross-section of the inner groove opening along the width direction is "U"-shaped to enhance the local strength of the beam.

[0014] Optionally, the height of the protruding structure is slightly higher than that of the middle cross beam, so that the cross beam body as a whole presents a structure of "low in the middle and high on both sides". At the same time, due to the curved surface design on both sides of the first side plate, the protruding structure has a larger width than the middle cross beam.

[0015] Optionally, the upper surface of the protruding structure can be a flat surface or a slightly curved surface to meet the requirements of different seat designs. At the same time, the upper surface is provided with positioning holes and assembly holes. The positioning holes are used to accurately position the car seat and the crossbeam body during assembly, so as to facilitate the subsequent correct assembly of the car seat; the assembly holes are used to assemble the car seat and the crossbeam body through bolt connection to form a whole.

[0016] Optionally, the crossbeam body is a non-uniform width structure, that is, the first side plate is curved on both sides along the length direction, which can effectively guide the conduction of force during side collision and improve the side impact strength.

[0017] Optionally, the first side panel is vertically arranged with respect to the top panel of the middle cross beam, and the first side panel is curved at both sides along the length direction, which makes the cross beam body present a non-uniform width design. The bending direction of the first side panel is toward the head of the car when viewed from top to bottom, which can effectively increase the legroom of the rear passengers and improve the riding comfort.

[0018] Optionally, the angle between the second side plate and the top plate of the middle cross beam can be a right angle or an obtuse angle. In the embodiment of the present invention, the angle between the second side plate and the top plate of the middle cross beam is an obtuse angle. In addition, the second side plate is a planar structure as a whole, which simplifies the structure of the seat cross beam.

[0019] Optionally, the connecting edge includes a first connecting edge, a second connecting edge and a third connecting edge; wherein the cross beam body is glued to the front floor of the car through the first connecting edge; the cross beam body is glued to the adjacent structural components through the second connecting edge; the cross beam body is glued to the inner door sill and the middle channel of the car through the third connecting edge. The first connecting edge is provided with a plurality of convex areas distributed at intervals along the length direction, and these convex areas are slightly higher than the main body plane of the first connecting edge, so as to better fit the uneven area of ​​the front floor of the car.

[0020] Optionally, to meet the performance requirements of the crossbeam, the crossbeam body is designed to have different thickness regions. The middle region of the crossbeam includes the middle crossbeam, and the ply thickness in this region is relatively thin to reduce weight and maintain sufficient bending stiffness; the protruding structure and the transition section are located on both sides of the crossbeam, which require higher local strength and have a relatively large ply thickness.

[0021] Optionally, in order to meet the strength and rigidity of the automobile seat crossbeam, the back of the crossbeam body is provided with reinforcing ribs to enhance the mechanical properties of the crossbeam; considering the force distribution of the crossbeam body, the reinforcing ribs are more densely distributed in some stress areas, such as near the assembly hole, to provide additional local support. At the same time, each reinforcing rib has a certain draft angle and chamfer to facilitate demoulding in the mold and reduce stress concentration.

[0022] Optionally, the crossbeam body is formed into an integrated crossbeam structure by means of compression molding and injection molding, thereby avoiding the defects of traditional welding methods.

[0023] The embodiment of the present invention provides a method for preparing a composite lightweight automobile seat crossbeam, comprising the following steps:

[0024] S101. Cleaning the surface of the mold for forming the seat beam to facilitate subsequent steps;

[0025] S102. Apply the gel coat on the working surface of the mold, and then apply a release agent;

[0026] S103. Select composite material prepreg for manual or mechanical laying according to the pre-designed laying plan;

[0027] S104. The laminated composite material sheet is preheated, and after the resin matrix is ​​softened, the sheet is quickly moved into a molding die, and a certain pressure and temperature are applied by the molding machine to cure it into a preform of the seat beam;

[0028] S105. Take out the molded preform and perform necessary post-processing, including trimming, punching, and pre-embedding, in preparation for subsequent assembly. In addition, the preform is preheated for a second time by non-contact heating methods such as infrared heating;

[0029] S106. Under high temperature conditions, quickly move the preheated molded preform into the injection mold. Select appropriate injection molding materials and perform injection molding reinforcement treatment. After the beam cools to room temperature in the mold, open the injection mold and take out the final parts.

[0030] Compared with the prior art, the automobile seat crossbeam provided by the embodiment of the present invention has at least the following beneficial effects:

[0031] The automobile seat crossbeam provided in the embodiment of the present invention adopts a carbon / glass hybrid fiber composite material to achieve lightweight crossbeam structure. The seat crossbeam improves the overall mechanical properties of the crossbeam through the structural design of "low in the middle and high on both sides". And the cross section of the crossbeam presents a "bow"-shaped structure, so that the crossbeam can effectively disperse the impact force. In addition, the crossbeam adopts a non-equal width design to enhance the side impact strength of the crossbeam. When laying the crossbeam, different layer thicknesses are used in different areas to meet local performance requirements and optimize the efficiency of material use. The integrated compression molding process for the crossbeam avoids the welding process required for traditional metal crossbeams, simplifies the production process and manufacturing costs, and improves production efficiency. The reinforcement ribs on the back of the crossbeam formed by injection molding further enhance the mechanical properties of the crossbeam to meet the performance requirements of the crossbeam. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 This is a structural schematic diagram of an automobile seat crossbeam installed on a front floor according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic structural diagram of a crossbeam of a car seat according to an embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the lateral structure of a car seat crossbeam according to an embodiment of the present invention;

[0036] Figure 4 for Figure 3 Sectional view of AA in the middle;

[0037] Figure 5 This is a schematic diagram of the back structure of a car seat crossbeam according to an embodiment of the present invention;

[0038] Figure 6 The present invention is a flow chart of a method for preparing a car seat crossbeam according to an embodiment of the present invention.

[0039] in:

[0040] 1. Beam body, 2. Middle section of beam, 3. First transition section, 4. Second transition section, 5. First protruding structure, 6. Second protruding structure, 7. Inner groove, 8. First side panel, 9. Second side panel, 10. First connecting edge, 11. Second connecting edge, 12. Third connecting edge, 13. First assembly hole, 14. First positioning hole, 15. Second assembly hole, 16. Second positioning hole, 17. First mounting surface, 18. Second mounting surface, 19. Transition section, 20. Protruding structure, 21. Reinforcing ribs, 22. Gluing area, 23. Front floor. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The directional nouns involved in the embodiments of the present invention, such as "upper", "lower", "side", etc., are generally represented by Figure 1 The relative relationship of the orientation shown in the figure is used as the basis, and these orientation terms are used only to more clearly describe the relationship between structures, not to describe absolute orientation. When the product is placed in different postures, the orientation may change, for example, "up" and "down" may be interchangeable.

[0043] The composite lightweight car seat crossbeam provided in the embodiment of the present invention increases the contact area with the door sill by adopting a non-equal width structure, thereby effectively improving the connection strength and side impact performance. The ply design of the crossbeam varies according to the stress conditions, with the middle area being thinner and the two side areas being thicker to increase local strength. Secondly, the reinforcement rib design on the back of the crossbeam further enhances the structural rigidity. The crossbeam of the present invention is integrally formed by molding and injection molding processes, avoiding additional reinforcements and cumbersome welding procedures, and achieving a lightweight structure.

[0044] In order to make the technical solutions and advantages of the present application more clear, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0045] See also Figure 1 , which shows a schematic diagram of the structure of the automobile seat crossbeam installed on the front floor 23 in an embodiment of the present invention, one end of the crossbeam body 1 is glued to the middle channel of the automobile, and the other end is glued to the inner door sill of the automobile. The crossbeam body 1 is made of composite materials as a whole, and has the characteristics of light weight and high strength.

[0046] like Figure 2 As described above, the crossbeam body 1 is divided into three parts in the length direction, namely, the middle crossbeam 2, the transition section 19 and the protruding structure 20. The two sides of the middle crossbeam 2 are respectively connected with the transition section 19 and the protruding structure 20. The transition section 19 is divided into a first transition section 3 and a second transition section 4, and the protruding structure 20 is divided into a first protruding structure 5 and a second protruding structure 6. The first transition section 3, the second transition section 4, the first protruding structure 5 and the second protruding structure 6 are mirror-symmetrical structures to provide a unified and coordinated structural layout.

[0047] It should be noted that the first transition section 3 is connected to the first protruding structure 5, and the second transition section 4 is connected to the second protruding structure 6. The first transition section 3 and the second transition section 4 are designed to be inclined in the height direction, with a certain inclination angle, to form a smooth transition from the middle crossbeam 2 to the protruding structure 20. The inclination is preferably 20 to 30 degrees, so as to improve the continuity and strength of the structure without increasing the weight. The first protruding structure 5 and the second protruding structure 6 are respectively located at the two ends of the crossbeam body 1, and the protruding structure 20 has a higher height than the transition section 19 and the middle crossbeam 2.

[0048] Optionally, a downwardly sunken inner groove 7 is provided in the middle of the cross beam body 1. The inner groove 7 extends along the length direction of the cross beam body 1 and penetrates the middle cross beam 2 and the transition section 19 to enhance the local strength of the seat cross beam and prevent the seat cross beam from bending when the car hits the side. The cross section of the inner groove along the width direction is "U" shaped, and its depth is half of the distance from the upper top surface of the middle cross beam 2 to the lower bottom surface of the first connecting edge 10, and its width is half of the width of the top plate of the middle cross beam 2. At the same time, the inner groove 7 has a certain draft angle, which is preferably 1 to 2 degrees, so as to facilitate the demoulding of the material and enhance the bending resistance of the inner groove 7. In addition, under the condition of meeting the performance, the design of the inner groove 7 makes the middle area of ​​the seat cross beam narrower, which helps to provide more space.

[0049] It should be noted that the side collision accident designed in the embodiment of the present invention specifically refers to a situation in which the side of a motor vehicle is hit by a foreign object during driving, which may cause the door structure to deform, thereby threatening the safety of the driver and passengers in the vehicle. In this context, the design of the crossbeam body 1 plays a crucial role, and its core function is to effectively absorb and disperse the impact energy through its structural design, thereby significantly improving the anti-deformation ability of the vehicle side.

[0050] like Figure 4 As shown, the cross beam body 1 is provided with a first side plate 8 and a second side plate 9 on both sides in the width direction, and one side of the first side plate 8 and the second side plate 9 is connected to the top plate of the middle cross beam 2. The cross beam cross section formed by the two side plates, the inner groove opening 7 and the top plate of the middle cross beam 2 presents a "bow" shaped structure, realizing continuous bending deformation. Compared with the traditional "J" shaped cross beam structure, the "bow" shaped structure optimizes the stress distribution of the material through the existence of the inner groove opening, increases the cross-sectional area of ​​the seat cross beam, and improves the bending resistance of the seat cross beam. When the car is hit from the side, the "bow" shaped structure can effectively disperse and absorb the impact force, thereby improving the safety performance of the car.

[0051] according to Figure 2 and Figure 3 As shown, the first protruding structure 5 and the second protruding structure 6 are symmetrically distributed, extending along the width direction of the vehicle body, and are respectively arranged on one side of the crossbeam body 1. This layout increases the distance between the first protruding structure 5 and the second protruding structure 6 and the center of the crossbeam body 1, thereby forming a reinforced stress point in the connection area between the vehicle seat and the seat crossbeam, thereby enhancing the connection stability between the vehicle seat and the seat crossbeam.

[0052] On the other hand, because the inclined design of the transition section 19 makes the height of the raised structure 20 slightly higher than the middle crossbeam 2, the crossbeam body 1 as a whole presents a "low in the middle and high on both sides" structure, so as to reduce the overall weight of the seat crossbeam and lower the center of gravity of the vehicle. The car seat is mainly assembled with the crossbeam body 1 through the positioning holes and assembly holes on the mounting surface of the raised structure 20, so the raised structure 20 is the main force-bearing area on the crossbeam body 1, and sufficient structural space is required to ensure the support strength of the seat crossbeam. To this end, the two sides of the first side plate 8 are designed with curved surfaces, so that the raised structure 20 not only has a higher height in the vertical direction, but also is correspondingly widened in the horizontal direction, forming a larger local area, so that it forms a more solid support point on both sides of the crossbeam. At the same time, this enlarged and widened design of the raised structure 20 makes its contact area with the car body larger, so that the crossbeam body 1 can withstand greater impact force in a side collision.

[0053] Optionally, in order to accurately position the car seat on the crossbeam body 1 in advance when the car seat is installed on the seat crossbeam, a first mounting surface 17 and a second mounting surface 18 are provided on the first protruding structure 5 and the second protruding structure 6, a first assembly hole 13 and a first positioning hole 14 are provided on the first mounting surface 17, and a second assembly hole 15 and a second positioning hole 16 are provided on the second mounting surface 18. The first positioning hole 14 and the second positioning hole 16 are used for accurate positioning of the car seat and the crossbeam body when they are assembled, and the first assembly hole 13 and the second assembly hole 15 are connected by bolts to assemble the car seat and the crossbeam body 1.

[0054] It should be noted that the first mounting surface 17 and the second mounting surface 18 of the raised structure 20 can be flat or slightly curved to ensure a stable connection between the car seat and the crossbeam and achieve precise fit to meet the design requirements of different seats.

[0055] The first positioning hole 14 and the second positioning hole 16 are used to ensure that the car seat can be pre-positioned by using the positioning member. During the installation process of the car seat, the positioning member passes through the first positioning hole 14 and the second positioning hole 16 and is connected to the car seat, thereby pre-positioning the position of the crossbeam body 1.

[0056] The first assembly hole 13 and the second assembly hole 15 can be pre-embedded with metal nuts or bolts. After the composite material is cured, the metal threaded parts can be directly used to pass the bolts through the first assembly hole 13 and the second assembly hole 14 to form a fixed connection with the car seat, thereby ensuring the strength and stability of the connection point and making the installation and removal of the car seat simple and quick.

[0057] Depend on Figure 2 and Figure 3It can be seen that the beam body 1 is provided with a first side plate 8 and a second side plate 9 on both sides in the width direction, one side of the first side plate 8 and the second side plate 9 is connected to the top plate of the middle beam 2, and the other sides are provided with connecting edges extending outwards.

[0058] Among them, the first side plate 8 is vertically arranged with the top plate of the middle cross beam 2, and the two sides of the first side plate 8 are designed as curved surfaces. The first side plate 8 has a certain curvature in the transition section 19 on both sides of the cross beam body 1 along the length direction, and its curvature radius is preferably R100 to R200 mm. Such a design makes the cross beam body 1 present a non-equal width structure. Compared with the equal width structure of the traditional car seat cross beam, this structure increases the contact area between the two side areas of the cross beam body 1 and the car door sill, which is more helpful to guide the conduction of force during side collision, so as to better disperse and absorb the impact force. In addition, the bending direction of the first side plate 8 is toward the front of the car when viewed from top to bottom, which can effectively increase the legroom of the rear passengers and ensure that the space utilization is maximized without sacrificing strength.

[0059] Optionally, the angle between the second side panel 9 and the top plate of the middle cross beam 2 can be a right angle or an obtuse angle. In the embodiment of the present invention, the angle between the second side panel 8 and the top plate of the middle cross beam 2 is an obtuse angle design, preferably 91 to 92 degrees, which is convenient for demoulding of the composite material and reduces the internal stress during the manufacturing process. At the same time, the obtuse angle structural design can also effectively improve the bending resistance of the cross beam body 1. In addition, the second side panel 9 is different from the first side panel 8. The curved surface design at both ends is cancelled, and the whole is a flat structure, which simplifies the structure of the seat cross beam and does not affect the leg space of the rear passengers.

[0060] It should be noted that, in order to ensure reliable connection between the cross beam body 1 and the automobile body, the first side plate 8 and the second side plate 9 are provided with connecting edges extending outwards, and the connecting edges extend along the length direction of the seat cross beam. The length of the connecting edges extending outwards can be determined according to actual conditions, and the cross beam body 1 is glued to the automobile body through the connecting edges. Among them, the connecting edges can be perpendicular to the middle part of the first side plate 8, or they can have a certain angle to meet the needs of different installation angles. In the embodiment of the present invention, the connecting edges are arranged vertically to enhance the connection stability between the cross beam body 1 and the automobile body.

[0061] In addition, the connecting edge structure is divided into three different parts according to different positions and connection relationships, namely, the first connecting edge 10, the second connecting edge 11 and the third connecting edge 12. The first connecting edge 10 is the part corresponding to the middle cross beam 2, and the first connecting edge 10 is designed to be bonded to the front floor 23. The first connecting edge 10 is provided with a plurality of convex areas distributed at intervals along the length direction, and these convex areas are slightly higher than the main plane of the first connecting edge 10, so as to better fit the uneven area of ​​the front floor 23 and improve the connection stability; the second connecting edge 11 is the part corresponding to the transition section 19 of the cross beam body 1, and its structure continues the slope of the transition section 19, forming a transition between the first connecting edge 10 and the third connecting edge 12, and the second connecting edge 11 is used for bonding with adjacent structural components; the third connecting edge 12 is connected to the convex structure 20 of the cross beam body 1, and the third connecting edge 12 on one side of the cross beam body 1 is used for bonding with the inner panel of the vehicle door sill, and the third connecting edge 12 on the other side is used for bonding with the middle channel of the vehicle.

[0062] Furthermore, due to the limitations of composite materials, the traditional welding connection method is not applicable in the embodiment of the present invention, so the embodiment of the present invention adopts adhesive bonding technology to achieve the connection between the cross beam body 1 and the automobile body. This connection method is mainly implemented on the connection edge of the cross beam body 1, specifically, in the adhesive bonding area 22 on the back of the cross beam body 1, that is, the place where the connection edge contacts the automobile body. The adhesive bonding connection method can not only reduce local stress concentration and play a certain energy absorption and shock reduction effect, but also avoid electrochemical corrosion between the composite material and the metal steel, thereby extending the service life of the seat cross beam.

[0063] Furthermore, because the connecting edge on the beam body 1 is glued to the automobile body, its connection strength is weaker than welding, so the connecting edge on the beam body 1 is designed as an integrated whole to make the contact surface between the connecting edge and the automobile body larger, ensuring that there is enough surface area for gluing, ensuring the reliability and durability of the connection, and the structural design is suitable for integrated molding.

[0064] Because the height of the car interior is limited, the seat crossbeam has a height limit when it is prepared, and reinforcements are generally used to meet the structural performance requirements of the car seat crossbeam. However, the crossbeam body 1 in the embodiment of the present invention avoids the use of additional reinforcements, and for this reason, the crossbeam body 1 is designed to have different regional thicknesses. Figure 3 As shown in the side view of the beam body 1, the beam body 1 is mainly divided into three parts with different thicknesses, namely, the left side, the middle and the right side, so as to adapt to different mechanical requirements and optimize the structural performance.

[0065] Among them, the middle area of ​​the crossbeam body 1 is the middle crossbeam 2. Since it mainly bears bending loads, it is designed to be relatively thin, reducing the overall weight while ensuring sufficient bending strength. In contrast, the two side areas are the raised structure 20 and transition section 19 of the crossbeam, which are the key parts connected to the car body, and the raised part is connected to the car seat to form the main force-bearing area. At the same time, during the molding process of the crossbeam body 1, it is necessary to drill holes on the first mounting surface 17 and the second mounting surface 18 of the raised structure 20, which will cause the fiber continuity of the crossbeam body 1 made of glass fiber to be destroyed, so that the strength of the crossbeam body 1 is weakened. Therefore, in order to meet higher load-bearing capacity and impact resistance, a thicker design is adopted in the raised structure 20 and transition section 19 area to enhance local stiffness and durability. In addition, the increased thickness of the raised structure 20 also helps to improve the side impact performance of the seat crossbeam.

[0066] like Figure 5 As shown, the back of the beam body 1 is provided with crisscrossed reinforcing ribs 21, and the design of the reinforcing ribs 21 follows the principles of structural mechanics and material mechanics properties. On the back of the beam body 1, the reinforcing ribs 21 are arranged in a grid shape to form a reinforced network structure. The density of the reinforcing ribs 21 is increased in areas with greater stress, such as the assembly holes of the beam body 1. In addition, the reinforcing ribs 21 are injection molded to simplify the manufacturing process and ensure that the reinforcing ribs 21 are tightly combined with the beam body 1.

[0067] The embodiment of the present invention provides a method for preparing a composite lightweight automobile seat crossbeam. Figure 6 The flowchart of the method for preparing the automobile seat crossbeam according to the embodiment of the present invention comprises the following steps:

[0068] S101. Cleaning the surface of the mold for forming the seat beam to facilitate subsequent steps;

[0069] The above-mentioned molds are generally steel molds or aluminum molds, and molds of other materials can also be used. The selection of specific materials is based on comprehensive considerations of factors such as cost, processing difficulty and durability.

[0070] S102. Apply the gel coat on the working surface of the mold, and then apply a release agent;

[0071] Due to the tiny defects on the mold surface, gel coat is needed to fill the mold surface defects to ensure the smooth surface of the manufactured seat beam and provide a good bonding foundation for the subsequent prepreg layer. After the gel coat layer is air-dried, a layer of release agent is applied to the mold surface to make the parts easy to remove from the mold.

[0072] S103. According to the pre-designed layup plan, select continuous glass fiber reinforced prepreg for manual or mechanical layup. During the layup process, ensure that the fiber direction and interlayer stacking sequence meet the design requirements to achieve the best mechanical properties;

[0073] Before the laying process, the material utilization efficiency is optimized through pre-cutting. According to the specific shape and size of the laying area, the required glass fiber prepreg size is cut to ensure that the corresponding laying area is covered exactly and material waste is avoided.

[0074] It should be noted that the embodiment of the present invention uses a thinner composite material layer thickness in the middle area, with a total of 18 layers and an overall thickness of 3.6 mm, to reduce weight and maintain the necessary bending stiffness. The two side areas use a larger layer thickness, with a total of 21 layers and an overall thickness of 4.2 mm, in which the continuous fiber reinforcement material is arranged along the load direction to enhance the tensile and compressive properties.

[0075] Furthermore, in order to meet the performance requirements of the beam body 1 when subjected to forces in multiple directions, the ply angle can be 0°, 45°, -45° or 90°. Among them, the ply fibers at 90° are arranged along the transverse direction of the beam body 1 to resist the transverse force caused by seat installation and vehicle movement; the plies at 45° and -45° provide the beam body 1 with good shear resistance to resist the shear force applied to the beam body 1 during side collision; and the ply fibers at 0° are arranged along the longitudinal direction of the beam body 1 to provide the main axial strength and stiffness. The ply angles of the embodiment of the present invention are designed to be 90° / 45° / -45° / 0° / 90° / 0° / -45° / 45° / 90°. For the first mounting surface 17 and the second mounting surface 18 of the raised structure 20, holes need to be drilled on these two mounting surfaces to assemble the seat, and this area is the main load-bearing area. Therefore, in the area of ​​the raised structure 20 of the beam body 1, the ply density at 0°, 45° and -45° is increased to adapt to higher local loads and impact resistance requirements.

[0076] On the other hand, the key to achieving this variable thickness design is to control the composite material layering process and molding process. In the molding stage, by adjusting the mold design and pressure distribution, the resin content and fiber volume ratio in different areas are controlled to achieve a predetermined thickness change. In addition, the variable thickness design can achieve a more flexible thickness transition and avoid stress concentration.

[0077] S104. The laminated composite material sheet is preheated to soften the resin matrix so that it can flow and fill the details of the mold better during the molding process. After preheating, the sheet is quickly moved into the molding mold and a certain pressure and temperature are applied by the molding machine to solidify it into a preform of the seat crossbeam;

[0078] It should be noted that the preheating treatment is intended to reduce the viscosity of the resin so that the resin can flow smoothly and fill the complex geometry of the mold, including some corners and grooves. At the same time, in order to avoid premature curing of the resin after preheating, the sheet needs to be moved into the molding mold in time and cured at the appropriate temperature and time.

[0079] S105. After the molded preform is removed, necessary post-processing is performed, including trimming to remove excess edge material, punching for subsequent assembly, and any required pre-embedded processes. In addition, the preform is preheated for a second time by non-contact heating methods such as infrared heating to prepare for subsequent injection molding reinforcement processing;

[0080] After the preform is molded, there may be flash or burrs on the edge due to mold restrictions. You can use a water jet or laser cutter to remove excess material along the preset edge line. This step needs to be strictly controlled to avoid damaging the internal structure of the composite material.

[0081] In addition, the drill speed and feed rate need to be controlled during the process of drilling holes in the preform to prevent damage to the composite material due to overheating or overloading. After the hole is drilled, the metal nut is bonded and fixed in the hole to ensure stability during the subsequent injection molding process.

[0082] S106. While maintaining a high temperature, quickly move the preheated molded preform into the injection mold. Add reinforcing ribs to the predetermined parts of the preform through the injection molding process to improve the local strength and overall stiffness of the beam. After the injection molding reinforcement treatment is completed, let the beam cool to room temperature in the mold to ensure that the injection molding material is fully solidified and forms a strong bond with the preform. Then open the injection mold and take out the final integrated seat beam component.

[0083] It should be noted that the preform needs to be maintained at a higher temperature to ensure good adhesion between the preform and the subsequent injection molding material. In order to minimize heat loss, a robotic arm is used to achieve rapid automated transfer and effective bonding of the injection molding material and the preform.

[0084] In addition, the selection of injection molding materials needs to consider whether they are compatible with the preform resin to ensure that a strong chemical bond can be formed between the two. In addition, the injection molding material should have both fluidity, curing rate and mechanical properties of the final product.

[0085] A composite lightweight seat crossbeam is provided in an embodiment of the present invention. The crossbeam body 1 is installed on the front floor 23, and the two sides of the crossbeam body 1 are respectively glued and fixed to the middle channel and the inner door sill of the car. The crossbeam body 1 adopts a non-uniform width structure design to enhance the contact area with the door sill of the vehicle. The crossbeam body 1 is divided into a middle crossbeam 2, a transition section 19 and a protruding structure 20 along the length direction. The protruding structure 20 has a higher height to enhance the local strength. The ply design varies according to the stress conditions. The middle area is thinner and the two side areas are thicker, so as to achieve lightweight while ensuring structural strength. The reinforcing rib design on the back of the crossbeam body 1 is integrated through molding and injection molding processes to further enhance the structural rigidity. The "bow"-shaped structure of the crossbeam cross section optimizes the stress distribution by the inner groove 7, improves the bending resistance, and can effectively disperse and absorb the impact force in the case of side collision. The connecting edge is connected to the car body by gluing, and the gluing area on the back ensures the reliability and durability of the connection. The mounting surface on the protruding structure 20 is provided with assembly holes and positioning holes to achieve accurate positioning and stable assembly of the car seat. The ply angles include 0°, 45° and 90° to meet multi-directional force requirements.

[0086] In general, the seat crossbeam in the embodiment of the present invention not only achieves lightweight, but also provides excellent structural performance and safety performance, meets the requirements of modern automobiles for energy saving, environmental protection and safety, and has good use value.

Claims

1. A composite lightweight automobile seat crossbeam structure, characterized in that: The invention comprises a car seat crossbeam body (1), wherein the crossbeam body (1) is installed on the front floor of the car, and the crossbeam body (1) is respectively glued and fixed to the middle channel and the inner door sill of the car on both sides in the width direction of the car body. The crossbeam body (1) is divided into three parts in the length direction, namely a middle crossbeam (2), a transition section (19) and a protruding structure (20); the transition sections (19) and the protruding structure (20) on both sides of the crossbeam body are mirror-symmetrical structures.

2. The automobile seat crossbeam structure according to claim 1, characterized in that: The transition section (19) is designed to be inclined and has a certain inclination angle, so as to form a smooth transition from the middle cross beam (2) to the raised structure (20).

3. The automobile seat crossbeam structure according to claim 1, characterized in that: The raised structure (20) is arranged along the length direction of the crossbeam, and its height is slightly higher than the middle crossbeam (2), so that the crossbeam body as a whole presents a "low in the middle and high on both sides" structure.

4. The automobile seat crossbeam structure according to claim 1, characterized in that: The cross beam body (1) is provided with a first side plate (8) and a second side plate (9) on both sides in the width direction; one side of the first side plate (8) and the second side plate (9) is connected to the top plate of the middle cross beam (2); the other sides are provided with connecting edges extending outwards; the cross beam body (1) is glued and fixed to the front floor of the automobile via the connecting edges.

5. The automobile seat crossbeam structure according to claim 1, characterized in that: The middle section structure formed by the top plate, the inner groove opening (7) and the two side plates of the middle section cross beam (2), that is, the cross section of the cross beam body (1) along the width direction presents a "bow"-shaped structure.

6. The automobile seat crossbeam structure according to claim 1, characterized in that: The crossbeam body (1) is a non-uniform width structure, that is, the first side plate (8) is designed to be curved on both sides along the length direction.

7. The automobile seat crossbeam structure according to claim 4, characterized in that: The angle between the first side plate (8) and the top plate of the middle cross beam (2) is a right angle, the angle between the second side plate (9) and the top plate of the middle cross beam (2) is an obtuse angle, and the second side plate (2) is a planar structure as a whole.

8. The automobile seat crossbeam structure according to claim 1, characterized in that: The middle area of ​​the beam body (1) includes the middle beam (2), which is relatively thin, and its structure and transition section (19) are located on both sides of the beam, and the ply thickness is relatively large.

9. The automobile seat crossbeam structure according to claim 1, characterized in that: The back of the crossbeam body (1) is provided with reinforcing ribs (21), and the reinforcing ribs (21) are more densely distributed in some stress-bearing areas, such as near the assembly holes, and each reinforcing rib (21) has a certain draft angle and chamfer.

10. A method for preparing a composite lightweight automobile seat crossbeam, characterized in that: The method for preparing the automobile seat crossbeam comprises: Clean the surface of the mold used to form the seat crossbeam to facilitate the subsequent steps; Apply the gel coat to the mold work surface, followed by a release agent; Select composite prepreg for manual or mechanical layup according to the pre-designed layup plan; The laminated composite material sheet is preheated, and after the resin matrix softens, the sheet is quickly moved into a molding die, and a certain pressure and temperature are applied by the molding machine to solidify it into a preform of the seat crossbeam; Take out the molded preforms and perform necessary post-processing, including trimming, punching, and pre-embedding, in preparation for subsequent assembly. In addition, the preforms are preheated for a second time by non-contact heating methods such as infrared heating. Under high temperature conditions, the preheated molded preform is quickly moved into the injection mold, the appropriate injection molding material is selected, and the injection molding reinforcement treatment is performed. After the beam is cooled to room temperature in the mold, the injection mold is opened and the final component is taken out.

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