Composite material seat back frame

Abstract

The present invention discloses a structural structure of a seat back frame using a continuous glass fiber reinforced composite material plate, and defines that the seat composite material back frame should be divided into a composite back plate in an occupant support area, a transition wing plate in a transition connection area, and a mounting plane. A mounting hole parameter of the mounting plane is provided, and a hole punching process parameter of a seat back frame using a continuous glass fiber reinforced composite material plate is provided. The hole punching process specifies the hole diameter range and the range of the distance between holes and the distance between holes and the edge of the frame, as well as the selection range of the frame and the plate thickness, so that the composite material frame using this punching process can be connected to metal parts by conventional bolts and can achieve better connection strength.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle accessories, in particular to a composite material seat back frame. Background Art

[0002] The car seat back frame is a core vehicle interior accessory. At present, the seat back frames of many vehicles are made of metal frame structures, which are heavy and greatly increase the overall weight of the vehicle. At the same time, since the frame structure cannot be used directly, it is necessary to cover the frame structure with sponge to improve the comfort of passengers. Since the back frame is a metal frame structure, when the rear passengers hit the back of the front chair, due to the characteristics of the frame structure, the energy absorption area for absorbing the impact force is small and the impact force cannot be dispersed, causing the passengers in the front seats to be easily subjected to concentrated and very large impact forces at the head, neck and waist, causing injuries to the front passengers.

[0003] With the development of science and technology, the preparation technology of car seat back frames is constantly developing towards energy saving, environmental protection and high efficiency. As a result, the emergence of composite seat frames has brought composite sheet technology into a new stage of development. Due to the need for energy saving and environmental protection, parts in industries such as automobiles, electronics and mechanical equipment are developing towards lightweight and miniaturization, and more and more metal materials are gradually being replaced by polymer composite materials. Most of the thermosetting polymer composite materials currently used have poor impact resistance and are not recyclable, while thermoplastic composite materials based on PP have low rigidity, poor wear and weather resistance, and insufficient heat resistance, which limits their scope of application. Therefore, the development of other thermoplastic composite materials with high strength, high modulus, light specific gravity, wear and corrosion resistance, excellent surface and good heat resistance has become a hot spot for new product development in the market.

[0004] Continuous fiber reinforced thermoplastic resin is composed of two parts: fiber and resin. Most thermoplastic resins have low tensile strength, but have high toughness and plasticity; while fibers have high tensile strength, but are easily damaged and difficult to form. The composite of fiber and resin complements the defects of the two, greatly improving the comprehensive performance of continuous fiber reinforced thermoplastic resin composites. Compared with traditional steel and aluminum materials, its density is about 1 / 5 of steel and about 1 / 2 of aluminum; its specific strength and specific modulus are also much higher than those of steel and aluminum alloys. Therefore, it has the characteristics of light weight under the same conditions of stiffness and strength, and is unmatched by other materials in terms of energy saving and improving the performance of components. The characteristic of glass fiber is its high elastic modulus. Through the high tensile strength and compressive strength of glass fiber, when glass fiber is introduced into thermoplastic matrix material, it can achieve purposeful reinforcement in these areas while obtaining a certain flexibility due to the high elastic elongation at break of glass fiber. Various composite materials with excellent performance can be made with ultra-high-strength glass fiber as reinforcement. They are widely used in the defense and military fields of aerospace, rockets, missiles, fighter jets, nuclear submarines, warships, tanks and other weapon equipment, especially suitable for automobile seat frames. Summary of the invention

[0005] The purpose of the present invention is to solve the various defects of the seat back frame in the prior art and to provide a composite material seat back frame which is light in weight, can quickly disperse and absorb impact force, is comfortable, safe, beautiful, has low production cost, and is easy to install and use.

[0006] At present, in the design process of seat back frames, complex curved shapes are usually adopted to meet the project's requirements for aesthetics and comfort. This is almost unlimited for the use of traditional metals. However, when continuous glass fiber composite panels are used as the main material for frame design, it is necessary to find a balance between the shape and the smoothness of the fiber.

[0007] To achieve the above-mentioned purpose, the composite material seat back frame of the present invention includes a continuous glass fiber reinforced thermoplastic composite back plate, the upper part of the continuous glass fiber reinforced thermoplastic composite back plate facing the passenger's back is provided with a concave arc segment, the lower part of the continuous glass fiber reinforced thermoplastic composite plate facing the passenger's back is provided with a convex arc segment, the concave arc segment and the convex arc segment are connected as a whole to form a continuous glass fiber reinforced thermoplastic composite back plate with a curved surface structure. Therefore, when combining the human body curve in a certain sitting posture, it is necessary to avoid large angle turning of the fiber as much as possible to affect the structural performance.

[0008] Take any point in the surface, take a circle with a diameter R (60≥R≥30, it is recommended that R be 50mm) passing through the point and on the section V of the surface A in this area, project the circle onto the surface A along the normal of the above-mentioned plane V, and the acute angle between the two farthest points on the edge of the intercepted spatial surface A1 and the two sections where the surface is located at the two points is α, which is 15°≥α≥0°, and it is recommended to be 5°≤α≤10°.

[0009] The height of the concave arc section and the convex arc section is 2-3:4-5; the height of the composite backboard is H: 80-100cm, and the widest part of the composite backboard is W: 55-65cm;

[0010] The design of the concave and convex arc sections focuses on passenger comfort and fit.

[0011] The backrest frame is made of a continuous glass fiber reinforced thermoplastic composite plate, which is formed by hot pressing and compounding 6 to 8 layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets. The unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets are made of thermoplastic resin, continuous ultra-high strength glass fiber and silane coupling agent. The mass ratio is 40:50:1.

[0012] The thermoplastic resin is selected from one or more of polyolefin resin, thermoplastic polyester, polyamide, polycarbonate, other general resins or high-performance engineering plastics.

[0013] After mechanical testing, the composite back panel has excellent mechanical properties and the ability to quickly disperse and absorb impact force.

[0014] On both sides of the composite backboard, transition wing panels extend smoothly downward and on both sides from the top of the backboard in accordance with the curve of the composite backboard; the transition wing panels extend out of the installation plane in the same form, and the installation plane adapts to the curve of the composite backboard.

[0015] The transition wing is connected to the adjacent composite back panel, and the average acute angle β between the transition wing and the two surfaces of the composite back panel at a certain measuring point is set to 75°≥β≥30°, and 30°≤β≤60° is recommended.

[0016] The transition wing plate extends from the top to the bottom of the composite back plate, and the width follows the curve from top to bottom, showing a smooth widening trend, and the width at the widest point is 20cm≥S≥8cm.

[0017] The design of the transition wing panel focuses on the mechanical wrapping and the rigidity and toughness of the transition from the composite panel to the installation plane. In the transition zone, on the basis of ensuring sufficient installation plane area, the fiber turning segments should be made to complete the angle change as much as possible to avoid the direct 90° angle and provide a better stress angle for the installation plane.

[0018] The transition wing plate extends smoothly downward and on both sides of the installation plane at the corresponding horizontal position of 15-25cm from the top of the composite back plate; the installation plane follows the curve of the transition wing plate from top to bottom, showing a smooth widening trend, and the widest width is 16cm≥M≥5cm; it not only has a beautiful shape, but also can protect the edge of the sponge layer set thereon, and also prevent the sponge layer set thereon from shifting left and right. The installation plane is provided with a combination installation hole for fixation;

[0019] The installation plane is roughly perpendicular to the plane where the composite back plate is located and is connected to the transition wing plate.

[0020] The design of the mounting surface focuses on providing the most secure support and fixation.

[0021] The composite back panel, transition wing panel and mounting plane are integrally formed to form a composite material seat back frame.

[0022] The backrest frame is connected to the seat base frame, and the seat base frame includes a horizontal frame fixed on the seat support frame. The horizontal frame is provided with a connecting plate connected to the lower part which is adapted to the mounting plane extending from the transition wing plates on both sides of the backrest frame. Matching mounting holes and connecting holes are respectively provided on the lower part of the mounting plane and the connecting plate. Fasteners pass through the mounting holes on the mounting plane on the corresponding side and the connecting holes on the connecting plate to fix the mounting plane and the connecting plate on the same side as a whole. The fasteners are bolts, screws, latches, etc.

[0023] The angle between the backrest frame 1 and the vertical direction is in the range of 20° to 30°, preferably 24°, which can make the passenger's sitting posture more comfortable.

[0024] Through the above design, when the car is emergency braked or stopped, when the passenger behind the seat hits forward, the head of the rear passenger leans forward and hits the concave arc section of the upper part of the continuous glass fiber reinforced thermoplastic composite plate. At the same time, the other body parts of the rear passenger lean forward and hit the convex arc section of the lower part of the continuous glass fiber reinforced thermoplastic composite plate. Through this special curved surface structure of the backrest frame, when its arc section is hit, the impact force can be quickly dispersed along the arc surface to greatly weaken the impact force and ensure the personal safety of the passengers in the front seat. When accelerating, the seat back can provide a close-fitting wrapping support, which is comfortable and safe.

[0025] Currently, seat frames are mainly made of metal pipes and sheet metal welded or bolted together. For seat frames made of continuous fiberglass boards, they still need to be assembled with seat functional components to form a complete product. However, composite materials cannot be welded with metals, nor can the opening process parameters of existing metals be directly used.

[0026] Another object of the present invention is to provide a process for opening a hole in a composite material plate, characterized in that the process stipulates that when the backrest frame and other components are riveted with bolts, a number of mounting holes need to be prefabricated. In order to maximize the connection and fixing strength of the composite seat backrest frame near the mounting holes after the prefabricated mounting holes, requirements need to be made for the minimum distance i between the mounting holes and the edge of the composite backrest frame, the hole center distance ii between any two mounting holes, the plate thickness t used for the backrest frame, and the value range of the mounting hole diameter d.

[0027] Furthermore, the diameter d of any of the mounting holes and the minimum distance i between the mounting hole and the edge of the backrest frame satisfy i≥2d. Combined with the spatial arrangement requirements of the seat design process, 3d≥i≥2d is preferred.

[0028] Furthermore, the hole center distance ii ≥ 2(d1+d2) between any two adjacent mounting holes with diameters d1 and d2 is preferably 2.5(d1+d2)≥ii≥2(d1+d2) in combination with the spatial layout requirements of the seat design process.

[0029] Furthermore, the composite material backrest frame plate thickness is 30≥t≥15mm, and considering the strength requirements of the automobile seat frame, preferably 30≥t≥24mm.

[0030] Furthermore, the diameter of the mounting hole is 12≥d≥6mm, and considering the strength requirements of the automobile seat frame and the performance of the composite material prefabricated mounting hole, preferably 10≥d≥8mm.

[0031] During the molding process, composite panels often experience delamination at the edges. When delamination occurs, the performance of the surrounding areas will be greatly weakened. Therefore, it is necessary to cut the panels to appropriate specifications to ensure that the product is within the required size range and will not be affected by delamination at the edges caused by the process. At the same time, it is also necessary to ensure that materials are saved as much as possible so that the product can be laid out and cut within the specifications of conventional panels.

[0032] Another object of the present invention is to solve the problem of unrolling and cutting composite material plates for making a seat back frame. A process for unrolling and cutting composite material plates is provided, wherein the process stipulates that when cutting composite material plates for making a seat back frame, the material should be saved as much as possible, and the normal size shrinkage factor and the overall edge expansion size that needs to be specially considered due to the delamination effect should be comprehensively considered.

[0033] Furthermore, the expansion dimension x and the plate thickness t satisfy 4t≥x≥2.5t, and x=3t is recommended.

[0034] The composite material seat back frame plate thickness is 30≥t≥15mm, and in combination with the strength requirements of the automobile seat frame, preferably 30≥t≥24mm;

[0035] Good pulling force and fixing effect can be obtained when the plate is subjected to stress.

[0036] The method for preparing the composite material seat back frame of the present invention comprises the following steps:

[0037] 1) Ingredients: Take one or more of polyolefin resin, thermoplastic polyester, polyamide, polycarbonate, other general resins or high-performance engineering plastics, mix with continuous ultra-high strength glass fiber and silane coupling agent according to mass ratio.

[0038] 2) Board making: using conventional technology to make a unidirectional continuous glass fiber reinforced thermoplastic resin prepreg; then selecting a suitable number of layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg according to the required board thickness t to form a continuous glass fiber reinforced thermoplastic composite board.

[0039] 3) Cutting and layout: Use 3D modeling software to unfold the spatial surface of the product into a plane surface. The unfolding algorithm uses the built-in algorithm of Catia, a commonly used software in the automotive industry;

[0040] The obtained plane surface profile is used for x incremental offset, and the range of x values ​​is given in the text;

[0041] The final contour after offset is laid out according to the principle of maximizing material utilization and the size of the existing raw material plate. During layout, the cutting contour gap is ≤3mm to ensure material utilization, and the cutting plan layout drawing is output;

[0042] 4) Customized mold: Customized mold according to design style, angles and backrest frame parameters;

[0043] 5) Skeleton forming: Calculate the amount of continuous glass fiber reinforced thermoplastic composite board before cutting according to the actual product amount;

[0044] According to the calculation results, CNC machining equipment is used to cut and take materials according to the layout drawing;

[0045] Place the cut pieces into a chain-driven electric oven and bake at 130°C for 10 minutes;

[0046] Put the heated sheet into the molding die and pressurize it in three steps: pre-pressing: 15% of the required pressure; actual pressing: 100% of the required pressure; holding pressure: 110% of the required pressure. Continue for 5 seconds; demould the product and trim it.

[0047] Drill holes according to the designed opening parameters of the mounting holes.

[0048] 6) Seat installation: Make the seat in the conventional way and install it for use.

[0049] Beneficial effects of the present invention:

[0050] The composite material seat back frame of the present invention adopts continuous glass fiber reinforced thermoplastic composite material, which is light in weight, has high mechanical properties, good flame retardancy, anti-aging and high temperature resistance, excellent comprehensive performance, low price and high cost performance. And due to these excellent properties of continuous glass fiber reinforced thermoplastic composite material, it is particularly suitable for automobile seats, which not only reduces weight and thickness but also ensures safety performance. And due to the characteristics of composite materials, it can also be convenient for shaping, and a curved back plate suitable for ergonomic performance is designed to fit the body curve to provide comfortable and stable support. It is also considered that the angle of the arc segment is corrected in view of collision deformation, so that it can better withstand the impact force and provide safe support. However, these properties can be fully exerted, and the basis is that it needs to be supported and fixed to the greatest extent. The present invention obtains the best hole position design through design, so that the hole can provide both sufficiently stable fixation and the maximum force performance of the overall frame, so that when the vehicle is in extreme conditions, the force provided by the hole position is sufficient to fix the seat frame and the hole position or the back plate material will not break. In the extension from the back plate to the installation plane, it is necessary to design a transition wing plate to match the angle and curve changes of the back plate and the installation plane. The present invention solves these problems perfectly through design. It also solves the technical problem that during the molding process of composite material blanks, the edge parts often have delamination phenomenon, and the performance of the area near the beginning of delamination will be greatly weakened. The size range required by the designed product is not affected by the delamination caused by the process at the edge, and it also ensures that materials are saved as much as possible, so that the product can be laid out and cut within the conventional plate specifications. The whole process makes the composite material seat back frame have outstanding substantial characteristics and significant progress compared with the existing technology. From design to production, it can save materials, reduce production costs, have excellent performance, and be easy to produce. The composite material seat back frame is perfectly suitable for car seats. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a side view, a back view and an oblique view of the composite material seat back frame.

[0052] Figure 2 To determine the angle α.

[0053] Figure 3 To determine the β angle.

[0054] Figure 4 For positioning of mounting holes.

[0055] Figure 5 Schematic diagram of the parameters of the blanking plate

[0056] In the figure: 1. composite back panel, 2. transition wing panel, 3. mounting plane, 4. concave arc segment, 5. convex arc segment, 6. mounting hole. DETAILED DESCRIPTION

[0057] The principles and features of the present invention are described below in conjunction with embodiments, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. The content of the present invention is described in detail below.

[0058] The method for preparing the composite material seat back frame of the present invention comprises the following steps:

[0059] 1) Ingredients: Take one or more of polyolefin resin, thermoplastic polyester, polyamide, polycarbonate, other general resins or high-performance engineering plastics, mix with continuous ultra-high strength glass fiber and silane coupling agent in a mass ratio of (40:50:1).

[0060] 2) Board making: using conventional technology to make unidirectional continuous glass fiber reinforced thermoplastic resin prepregs; then selecting appropriate layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepregs according to the required board thickness t=25 mm, hot pressing and compounding to form a continuous glass fiber reinforced thermoplastic composite board.

[0061] 3) Cutting and layout: Use 3D modeling software to unfold the spatial surface of the product into a plane surface. The unfolding algorithm uses the built-in algorithm of Catia, a commonly used software in the automotive industry;

[0062] The obtained plane surface profile is offset by x=75mm increments;

[0063] The final contour after offset is laid out according to the principle of maximizing material utilization and the size of the existing raw material plate. During layout, the cutting contour gap is ≤3mm to ensure material utilization, and the cutting plan layout drawing is output;

[0064] 4) Customized mold: Customize the mold according to the design style, angles and backplane parameters;

[0065] 5) Skeleton forming: Calculate the amount of continuous glass fiber reinforced thermoplastic composite board before cutting according to the actual product amount;

[0066] According to the calculation results, CNC machining equipment is used to cut and take materials according to the layout drawing;

[0067] Place the cut pieces into a chain-driven electric oven and bake at 130°C for 10 minutes;

[0068] Put the heated sheet into the molding die and pressurize it in three steps: pre-pressing: 15% of the required pressure; actual pressing: 100% of the required pressure; holding pressure: 110% of the required pressure. Continue for 5 seconds; demould the product and trim it.

[0069] Drill holes according to the designed opening parameters.

[0070] 6) Seat installation: Make the seat in the conventional way and install it for use.

[0071] Example 1: Mounting hole parameters provide excellent pulling force and fixation

[0072] The composite material seat back frame is designed with S=20cm; M=16cm; β=60°; the height of the concave arc segment and the convex arc segment is 3:5; the composite back plate is H: 100cm high, and the widest part of the composite back plate is W: 65cm. The back frame is formed by hot pressing and compounding 8 layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets; 2 mounting holes with diameters d1=d2=8mm are opened; i is equal to 20mm; ii=36mm; t=25mm.

[0073] The backrest frame made according to the above parameters was subjected to a backrest strength test under the test conditions of GB13057-2003 standard. According to the test heights H1 (500mm) and H2 (750mm) required by the standard, the two test tensions were F1=4100N and F2=1425N respectively, and the corresponding displacements of the two test points were x1=125mm and x2=60mm.

[0074] Embodiment 2:

[0075] The composite material seat back frame is designed with S=20cm; M=16cm; β=60°; the height of the concave arc segment and the convex arc segment is 3:5; the composite backboard is H: 100cm high, and the widest part of the composite backboard is W: 65cm. The back frame is formed by hot pressing and compounding 8 layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets; 2 mounting holes with diameters d1=d2=11mm are opened; ii=60mm; i is equal to 35mm; t=25mm.

[0076] The backrest frame made according to the above parameters was subjected to a backrest strength test under the test conditions of GB13057-2003 standard. According to the test height H1 (500mm) and H2 (750mm) required by the standard, the two test tensions were F1=3950N and F2=1308N respectively, and the corresponding displacements of the two test points were x1=230mm and x2=85mm.

[0077] Comparative Example 1:

[0078] The composite material seat back frame is designed with S=20cm; M=16cm; β=60°; the height of the concave arc segment and the convex arc segment is 3:5; the back frame is H: 100cm high and W: 65cm at the widest point. The back frame is formed by hot pressing and compounding 8 layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets; 2 mounting holes with diameters d1=d2=15mm are opened; i is equal to 37.5mm; ii=67.5mm; t=25mm.

[0079] The backrest frame made according to the above parameters was subjected to a backrest strength test under the test conditions of GB13057-2003 standard. According to the test heights H1 (500mm) and H2 (750mm) required by the standard, the two test tensions were F1=3910N and F2=1298N respectively, and the corresponding displacements of the two test points were x1=285mm and x2=92mm.

[0080] Example 3

[0081] The composite material seat back frame is designed with S=20cm; M=16cm; β=60°; the height of the concave arc segment and the convex arc segment is 3:5; the back frame is H: 100cm high and W: 65cm at the widest point. The back frame is formed by hot pressing and compounding 8 layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets; 2 mounting holes with diameters of d1=8mm (i=24mm) and d2=10mm (i=30mm) are opened; ii=50mm; t=25mm.

[0082] The backrest frame made according to the above parameters was subjected to a backrest strength test under the test conditions of GB13057-2003 standard. According to the test heights H1 (500mm) and H2 (750mm) required by the standard, the two test tensions were F1=3985N and F2=1320N respectively, and the corresponding displacements of the two test points were x1=185mm and x2=79mm.

[0083] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a composite material seat back frame, characterized in that: The steps include: 1) Ingredients: Take one or more of polyolefin resin, thermoplastic polyester, polyamide, polycarbonate, continuous ultra-high strength glass fiber and silane coupling agent and mix them according to the mass ratio; 2) Board making: a unidirectional continuous glass fiber reinforced thermoplastic resin prepreg is made; then, a suitable number of layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg are selected according to the required board thickness t, and hot-pressed to form a continuous glass fiber reinforced thermoplastic composite board; 3) Cutting and layout: Use 3D modeling software to unfold the spatial surface of the product into a plane surface. The unfolding algorithm uses the built-in algorithm of the software Catia; The obtained plane curved surface contour is offset by x increment, and x and the plate thickness t satisfy 4t≥x≥2.5t; the final contour after offset is cut with a contour gap of ≤3mm during layout; 4) Customized mold: Customize the mold according to the design style, angles and backrest frame parameters; 5) Skeleton forming: Calculate the amount of continuous glass fiber reinforced thermoplastic composite board before cutting according to the actual product amount; According to the calculation results, CNC machining equipment is used to cut and take materials according to the layout drawing; Place the cut pieces into a chain-driven electric oven and bake at 130°C for 10 minutes; Put the heated sheet into the molding die and pressurize it in three steps: pre-pressing: 15% of the required pressure; actual pressing: 100% of the required pressure; Holding pressure: 110% of the required pressure; lasting for 5 seconds; demoulding and trimming of the product; Punch holes according to the designed opening parameters of the mounting holes; 6) Seat installation: Make the seat, install and use.

2. A composite material seat back frame, comprising a continuous glass fiber reinforced thermoplastic composite back plate, wherein the upper portion of the continuous glass fiber reinforced thermoplastic composite back plate facing the passenger's back is provided with a concave arc segment, and the lower portion of the continuous glass fiber reinforced thermoplastic composite plate facing the passenger's back is provided with a convex arc segment, wherein the concave arc segment and the convex arc segment are connected as a whole to form a continuous glass fiber reinforced thermoplastic composite back plate with a curved surface structure, characterized in that: The preparation method according to claim 1 is used for manufacturing; transition wing plates are arranged on both sides of the composite back plate, and installation planes are arranged on both sides of the transition wing plates; the composite back plate, the transition wing plates and the installation planes are integrally formed into a composite material seat back frame; the installation plane is prefabricated with a plurality of installation holes with a diameter d; the diameter d of any installation hole and the minimum distance i between the installation hole and the edge of the back frame satisfy 3d≥i≥2d; the transition wing plates extend from the top to the bottom of the composite back plate, and the width follows the curve from top to bottom, showing a smooth widening trend, and the width at the widest point is 20cm≥S≥8cm; the installation plane follows the curve of the transition wing plates from top to bottom, showing a smooth widening trend, and the width at the widest point is 16cm≥M≥5cm; the hole center spacing ii≥2(d1+d2) between any two adjacent installation holes with diameters d1 and d2.

3. The composite material seat back frame according to claim 2, characterized in that: The hole center spacing ii between any two adjacent mounting holes with diameters d1 and d2 satisfies 2.5(d1+d2)≥ii≥2(d1+d2).

4. The composite material seat back frame according to claim 2, characterized in that: The composite material backrest frame has a thickness of 30 mm ≥ t ≥ 15 mm.

5. The composite material seat back frame according to claim 2, characterized in that: The diameter of the mounting hole is 12 mm ≥ d ≥ 6 mm.

6. The composite material seat back frame according to claim 2, characterized in that: The transition wing plate is connected to the adjacent composite back plate, and the average acute angle between the transition wing plate and the composite back plate at any measuring point of the connecting line is β, which is set to 75°≥β≥30°.

7. The composite material seat back frame according to claim 2, characterized in that: The heights of the concave arc segment and the convex arc segment are 2-3:4-5.

8. The composite material seat back frame according to claim 2, characterized in that: The height H of the composite backboard is 80cm-100cm, and the widest part W of the composite backboard is 55cm-65cm.

9. The composite material seat back frame according to claim 2, characterized in that: The backrest frame is made of a continuous glass fiber reinforced thermoplastic composite board, and the continuous glass fiber reinforced thermoplastic composite board is formed by hot-pressing and compounding 6 to 8 layers of unidirectional continuous glass fiber reinforced thermoplastic resin prepreg sheets.

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