Lightweight rim and efficient production method thereof

Abstract

The invention relates to the technical field of rim manufacturing, in particular to a light-weight rim and an efficient production method thereof. The light-weight rim comprises an upper body, a lower body, a thickening body set and an external whole. The upper body, the lower body and the thickening body are connected into a combined body, and the combined body is integrally wrapped with the outer part; the upper body is formed by laying prepreg and performing compression molding; the thickened body group is subjected to injection molding through a polyurethane foam reaction; and the lower body and the outer whole body are formed in a mode of combining a three-dimensional weaving technology and an HP-RTM (High Pressure-Resin Transfer Molding) forming process. The light-weight wheel rim has the advantage that the light weight of the wheel rim is achieved through the carbon fibers and the rigid polyurethane foam. On the premise that the requirement for the size of the rim structure is not affected, the integrated structure is divided into an upper body, a lower body, a thickening body set and an external whole. The non-bearing position (the thickening body group position), namely the interlayer between the upper body and the outer whole body and the interlayer between the lower body and the outer whole body, are filled with rigid polyurethane foam.

Description

Technical Field

[0001] The invention relates to the technical field of rim manufacturing, and in particular to a lightweight rim and an efficient production method thereof. Background Art

[0002] With the development of the new energy industry, lightweighting of automobiles has become a mainstream trend. As an important component of the entire vehicle, the wheel hub has a vital bearing capacity. Reducing the weight of the wheel hub helps to improve the vehicle's handling, acceleration performance and fuel economy. Therefore, it is extremely important to produce lightweight, high-strength and fatigue-resistant lightweight wheels. However, due to the low production efficiency and long production cycle of composite wheel hubs, their mass production faces challenges. At the same time, the fiber preform manufacturing technology (3D weaving) has limitations in the molding of the rim connection flange structure. Therefore, many car manufacturers only use composite wheel hubs on specific models of high-end brands, limiting their wide application. Summary of the invention

[0003] In view of this, the present invention aims to provide a lightweight rim and an efficient production method thereof, by dividing the rim into four parts: an upper body, a lower body, a thickened body group, and an external integral body, and dividing its production into five steps: upper body molding, lower body molding, thickened body group molding, and external integral body molding. Each step is mutually complementary, and is suitable for assembly line mass production.

[0004] To achieve the above-mentioned purpose, the technical solution created by the present invention is implemented as follows: a lightweight rim, including an upper body, a lower body, a thickened body group and an outer body; the upper body, the lower body and the thickened body group are connected into a combination, and the outer body is wrapped on the outside of the combination; the upper body is molded by prepreg laying; the thickened body group is made of polyurethane foam; the lower body and the outer body are both molded by combining three-dimensional weaving technology with HP-RTM molding process.

[0005] Further, the thickening body group includes at least five thickening bodies.

[0006] Furthermore, the five thickened bodies are respectively a first thickened body, a second thickened body, a third thickened body, a fourth thickened body and a fifth thickened body.

[0007] Furthermore, the first thickened body, the second thickened body, and the third thickened body are located between the upper body and the outer whole; the fourth thickened body and the fifth thickened body are located between the lower body and the outer whole.

[0008] An efficient production method for a lightweight rim is used to produce the above-mentioned lightweight rim, and the specific steps are as follows: S1: The upper body is formed by using a prepreg lay-up compression molding process.

[0009] S2: preparing a polyurethane composite liquid and injecting it into a polyurethane mold to form a hard polyurethane foam; then, processing the polyurethane foams through mechanical processing to respectively add five thickening bodies of the thickening body group.

[0010] S3: First, a lower body preform is made by using a three-dimensional weaving technology, and then a HP-RTM molding process is used to form the lower body.

[0011] S4: Connect the formed upper body, thickened body group and lower body into a combined body.

[0012] S5: First, a three-dimensional weaving technology is used on the assembly to form an external integral preform, and then the HP-RTM molding process is used to form the external integral body, and finally a lightweight rim is made.

[0013] Furthermore, the specific steps of upper body forming in step S1 are as follows: S11: The prepreg is made into a fan-shaped sample and laid out into a ring-shaped plate.

[0014] S12: applying a release agent to the inner surface of the upper body mold, and preheating the upper body mold to a first preset temperature; placing the annular plate on the upper body mold, closing the molds for compression molding, and forming an uncured upper body.

[0015] S13: curing the uncured upper body at the second preset temperature and the first preset time, and taking out the upper body after curing.

[0016] Furthermore, the specific steps of forming the thickened body in step S2 are as follows: S21: Mixing the polyurethane raw material, the catalyst and the stabilizer in a predetermined ratio to form a polyurethane composite material; during the stirring of the polyurethane composite material, preheating the polyurethane mold to a third preset temperature, and applying a release agent on the surface of the polyurethane mold.

[0017] S22: injecting the polyurethane composition mixed in step S21 into a polyurethane mold for chemical reaction, and forming a hard polyurethane foam after curing.

[0018] S23: The rigid polyurethane foam is processed into five thickened bodies of the thickened body group through mechanical processing.

[0019] Furthermore, the specific steps of forming the lower body in step S3 are as follows: S31: constructing a lower body preform mold, and determining a unit cell thickness of the lower body according to the fiber volume content of the lower body.

[0020] S32: Determine the unit cell as the smallest preform unit, and realize the spatial orientation of the fiber bundle by controlling the movement of the yarn of the fiber bundle in four directions.

[0021] S33: During the weaving process, for the gradually thickening area of ​​the cross section of the lower body, the number of rows of yarn is first guided, and then the reverse yarn is filled in sequence; for the conical area of ​​the longitudinal section of the lower body, the weaving method from the large end to the small end is adopted; finally, the four-step weaving method is continued until the weaving of the lower body preform is completed.

[0022] S34: placing the braided lower body preform on the mold of the HP-RTM press.

[0023] S35: After the HP-RTM press is started, when the pressure, temperature and vacuum degree reach the preset first pressure value, first temperature value and first vacuum degree value respectively, high-pressure injection of resin and curing agent is started to form an uncured lower body.

[0024] S36: After the uncured lower body is cured, the lower body is removed from the mold.

[0025] Furthermore, the specific steps of connecting the upper body, the thickened body group and the lower body into a combined body in step S4 are as follows: S41: Connect the formed upper body and lower body by screws, and glue them together at the connection to ensure that the upper body and the lower body are integrated into one.

[0026] S42: Each thickened body in the thickened body group is glued to the corresponding preset position of the upper body and the lower body to form a combined body.

[0027] Furthermore, the specific steps of the external integral forming in step S5 are as follows: S51: The four-step three-dimensional weaving technology is used on the assembly to weave the external integral preform.

[0028] S52: Placing the outer monolithic preform on the HP-RTM press.

[0029] S53: After the HP-RTM press is started, when the pressure, temperature and vacuum degree reach the preset second pressure value, second temperature value and second vacuum degree value respectively, high-pressure injection of resin and curing agent is started to form the rim.

[0030] S54: After the resin and the curing agent are cured, the rim is removed from the mold.

[0031] Compared with the prior art, the invention can achieve the following beneficial effects: 1) The rim is lightweighted by using carbon fiber and rigid polyurethane foam. Without affecting the rim structural size requirements, the integrated structure is divided into four parts: upper body, lower body, thickened body group and external whole. The interlayer located in the non-load-bearing position (thickened body group position), that is, between the upper body and the external whole, and between the lower body and the external whole, is filled with rigid polyurethane foam.

[0032] 2) The rim structure has a strong load-bearing capacity. The key load-bearing position is divided into the upper body and the lower body. The external part is integrated, and the fiber continuity of each part is achieved to the greatest extent, which improves the structural efficiency and solves the flange surface forming problem in the traditional three-dimensional weaving process.

[0033] 3) According to the structural characteristics of each part, the corresponding rapid prototyping process is selected. The upper body adopts the prepreg laying rapid prototyping process to improve the laying efficiency and facilitate mechanized production. The lower body combines the three-dimensional weaving and HP-RTM molding process, and the thickened area adopts the rigid polyurethane foam injection molding process. The combination formed by connecting the upper body, lower body and thickened body is used as the mold for the external integral molding, and then combined with the three-dimensional weaving and HP-RTM molding process to complete the production of the rim, so as to achieve the efficient production cycle requirements and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 is a schematic structural diagram of a lightweight rim provided according to an embodiment of the present invention; Figure 2 is a partial enlarged view of a lightweight wheel rim position A provided according to an embodiment of the present invention; Figure 3 is a partial enlarged view of a lightweight wheel rim position B provided according to an embodiment of the present invention; Figure 4 is a flow chart of a lightweight rim manufacturing method provided in an embodiment of the present invention; Figure 5 2 is a schematic structural diagram of the basic principle of four-step weaving provided by an embodiment of the present invention; Figure 6 It is a schematic diagram of the four-step weaving steps provided according to an embodiment of the present invention.

[0035] The reference numerals include: 1, upper body; 2, lower body; 3, external whole; 4, first thickened body; 5, second thickened body; 6, third thickened body; 7, fourth thickened body; 8, fifth thickened body. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0039] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0040] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0041] like Figure 1-Figure 3 As shown, a lightweight rim provided by an embodiment of the present invention includes an upper body 1, a lower body 2, a thickened body group and an outer body 3. The upper body 1, the lower body 2 and the thickened body group are connected to form a combination, and the outer body 3 is wrapped around the outside of the combination. The upper body 1 is molded by laying prepreg. The thickened body group is made of polyurethane foam. The lower body 2 and the outer body 3 are both molded by combining three-dimensional weaving technology with HP-RTM molding process.

[0042] HP-RTM is the abbreviation of High Pressure Resin Transfer Molding. The full name is High Pressure Resin Transfer Molding. The HP-RTM process uses high pressure to mix the resin and inject it into a vacuum-tight mold pre-laid with fiber reinforcement and pre-set inserts. After resin flow filling, impregnation, curing and demoulding, a composite material product is obtained.

[0043] The thickening body group includes at least five thickening bodies. In this embodiment, five thickening bodies are sequentially arranged from the upper body 1 to the lower body 2, namely, the first thickening body 4, the second thickening body 5, the third thickening body 6, the fourth thickening body 7 and the fifth thickening body 8. Among them, the first thickening body 4, the second thickening body 5, and the third thickening body 6 are located between the upper body 1 and the external whole 3. The fourth thickening body 7 and the fifth thickening body 8 are located between the lower body 2 and the external whole 3.

[0044] like Figure 4 As shown, an efficient production method of a lightweight rim is used to produce the above-mentioned lightweight rim, and the specific steps are as follows: S1: The upper body 1 is manufactured by using a prepreg placement compression molding process.

[0045] The specific steps of forming the upper body 1 in step S1 are as follows: S11: A prepreg composed of HF30F fiber and E4525 glue is selected. The width of the prepreg is 300 mm and the thickness of a single layer is 0.2 mm. First, the blanking machine cuts the prepreg into multiple fan-shaped samples. Then, the multiple fan-shaped samples are laid into the required annular plate. In this embodiment, six fan-shaped samples form an annular plate. A total of 10 layers of the annular plate are laid, and the laying angles of two adjacent laying layers are different. The total thickness of the 10 layers is 2 mm.

[0046] S12: A release agent is applied to the inner surfaces of the upper mold and the lower mold of the upper body mold, and then the upper body mold is placed in a curing oven for preheating to 40°C-50°C (a first preset temperature). The annular plate is placed on the lower mold of the upper body mold, and the upper mold and the lower mold of the upper body mold are molded together and molded to form an uncured upper body.

[0047] S13: After the upper body mold is closed, it is placed in a curing furnace to cure the uncured upper body, the curing temperature is 120±5°C (the second preset temperature), and the curing time is 0.5h (the first preset time). After curing, the upper body 1 is demoulded and removed from the upper body mold, and the surface of the upper body 1 is cleaned.

[0048] S2: The thickened body group is formed by polyurethane foam reaction injection molding.

[0049] The specific steps of thickening body forming in step S2 are as follows: S21: The polyurethane raw material, catalyst and stabilizer are mixed in a ratio of 7:2:1 (predetermined ratio), and the stirring is continued for 5s-10s at a stirring speed of 1000r / min to form a polyurethane composite material; during the stirring of the polyurethane composite material, the polyurethane mold is preheated to 55℃-60℃ (the third preset temperature), and a release agent is applied to the surface of the polyurethane mold.

[0050] In other embodiments, the polyurethane mold is preheated to 55° C.-60° C. (the third preset temperature) after the polyurethane composition is stirred.

[0051] S22: injecting the polyurethane composition mixed in step S21 into the polyurethane mold through a nozzle for chemical reaction, and curing at room temperature for 0.5 hours to form a hard polyurethane foam.

[0052] S24: through mechanical processing, the rigid polyurethane foam is processed into five thickened bodies of the thickened body group, namely, the first thickened body 4, the second thickened body 5, the third thickened body 6, the fourth thickened body 7 and the fifth thickened body 8.

[0053] S3: Firstly, a lower body preform is made by using a three-dimensional weaving technology, and then the lower body 2 is formed by using a HP-RTM process.

[0054] The specific steps of forming the lower body 2 in step S3 are as follows: S31: constructing a lower body preform mold, and determining a unit cell thickness of the lower body preform according to the fiber volume content of the lower body 2.

[0055] According to the required fiber volume content of the lower body 2, the thickness of the unit cell is calculated and determined to ensure that the lower body preform has the required mechanical and physical properties.

[0056] The three-dimensional woven special-shaped carbon fiber preform adopts a three-dimensional four-way woven structure. In one woven cycle, there are 4 woven yarns. The fiber volume content reflects the density of the fabric. Generally, the higher the fiber volume content, the better the mechanical properties of the composite material of the preform. According to the following formula, the fiber volume content calculation formula is used to determine the thickness of the unit cell.

[0057]

[0058] in: is the thickness of the unit cell; For flower width; For the flowers to be high; For the flowers are thick; is the line density; is the body density.

[0059] S32: Determine the unit cell as the smallest preform unit, and realize the spatial orientation of the fiber bundle by controlling the movement of the yarn in four directions (i.e., the positive and negative directions of the X-axis and the positive and negative directions of the Y-axis).

[0060] S33: The circumferential area of ​​the cross section of the lower body 2 is a gradually thickened preform, and the axial area of ​​the longitudinal section of the lower body 2 is a cone.

[0061] During the weaving process, for the gradually thickening area of ​​the cross section of the lower body 2, the number of yarn rows is first self-guided, and then the reverse yarn is filled in sequence according to the predetermined weaving order to ensure that the yarn is evenly distributed on the cross section; for the cone area of ​​the longitudinal section of the lower body 2, the weaving method from the large end to the small end is adopted. During the weaving process, when the yarn reaches the small end of the cone, the excess yarn is cut off from the head end. Then, the spindle is moved inward to fill the vacant position caused by cutting the yarn to ensure that the preform structure of the cone part is complete. After completing the weaving of the cross section and longitudinal section of the lower body 2, continue with the four-step weaving. By controlling the movement of the weaving yarn in four directions, the spatial orientation of the fiber bundle is achieved to ensure the overall performance and quality of the preform.

[0062] like Figure 5 , Figure 6 As shown, the basic principle of four-step weaving: The yarn carriers are arranged in rows and columns on the knitting machine chassis and move in the X and Y directions. The preforms are formed in the Z direction. In one machine cycle, the yarn carriers move in four steps, and each step moves to a neighboring position.

[0063] In the first step, the yarn carriers in adjacent rows are moved alternately one position in the X direction. In the second step, the yarn carriers in adjacent columns are moved alternately by one position in the Y direction.

[0064] In the third and fourth steps, the movement direction of the yarn carrier is opposite to that of the first and second steps respectively.

[0065] After the yarn carrier moves in four steps, the arrangement of the yarn carrier on the machine chassis returns to the initial position, completing a machine cycle.

[0066] The following is a specific example of using three-dimensional weaving technology to make a lower body preform.

[0067] The selected braiding machine has a total of five-ring braiding spindles, with a total number of 320 braiding spindles. The yarn tube used in the present invention is made of nylon PA, with an outer diameter of 65 mm, an inner diameter of 20 mm, a yarn winding height of 200 mm, and a yarn storage capacity of 100 mm. The formula for calculating the yarn storage capacity of the yarn tube is: .

[0068] in: The yarn storage capacity of the bobbin, in mm 3 , is the yarn winding height, in mm; is the radius of the bobbin (including the carbon fiber yarn wound on it), in mm; is the inner diameter of the yarn tube, in mm; is the radius of the carbon fiber, in mm; is the cross-sectional area of ​​the carbon fiber, in mm 2 ; The length of carbon fiber stored in the bobbin, in mm.

[0069] The diameter of the three-dimensional braided lower body preform is 542mm, the angle required to braid the sleeve is 60°, and the fiber coverage factor of the lower body preform is 55%-60%. The calculation formula for the braiding angle is: , in, is the dial speed, in r / s; is the diameter of the braided preform, in m; is the number of dials; is the traction speed in m / s.

[0070] The fiber cover factor formula is: .

[0071] is the fiber volume fraction of the preform, is the number of yarns, is the yarn width, is the core mold radius.

[0072] S34: The braided lower body preform is placed on the mold of the HP-RTM press, and the HP-RTM press is closed and connected to vacuum and oil temperature pipelines.

[0073] S35: After the HP-RTM press is started, when the pressure, temperature and vacuum degree reach the preset first pressure value, first temperature value and first vacuum degree value respectively, high-pressure injection of resin and curing agent is started to form the shape of the lower body 2.

[0074] The HP-RTM press is a hydraulic press, and the pressure parameters are set to 400T-500T (the first pressure value). After the HP-RTM press mold is closed, the valve and vacuum gauge are connected to the upper mold opening of the mold, and the air pump is used to evacuate the vacuum to -0.095Mpa to -0.1Mpa (the first vacuum value). When the mold temperature controller heats the HP-RTM press mold to 60-65℃ (the first temperature value), the mixed glue of resin and curing agent begins to be injected. S36: After the mixed glue liquid of the resin and the curing agent is cured, the mold is opened to take out the lower body 2, and the surface of the molded lower body 2 is cleaned. The curing temperature is 120° C. and the curing time is 0.5 h.

[0075] S4: Connect the formed upper body 1, thickened body group and lower body 2 into a combined body.

[0076] The specific steps of forming the assembly in step S4 are as follows: S41: The formed upper body 1 and lower body 2 are butt-jointed and drilled to form connection holes. The upper body 1 and lower body 2 are connected by screws and adhesive is used to bond the connection to ensure that the upper body 1 and lower body 2 are combined into one.

[0077] S42: Each thickened body in the thickened body group is glued to the corresponding preset positions of the upper body 1 and the lower body 2 (i.e. Figure 2 The positions of the first thickened body 4, the second thickened body 5 and the third thickened body 6, Figure 3 The positions of the fourth thickened body 7 and the fifth thickened body 8 are arranged in the middle to form a combined body.

[0078] S5: First, a three-dimensional weaving technology is used on the assembly to form an external integral preform, and then the HP-RTM process is used to form the external integral body 3 to form a lightweight rim.

[0079] The specific steps of step S5 are as follows: S51: The four-step three-dimensional weaving technology is used on the assembly to weave the external integral preform. The three-dimensional weaving method of the external integral preform is similar to the three-dimensional weaving method of the lower body preform, and will not be described in detail here. S52: Placing the outer monolithic preform on the HP-RTM press.

[0080] S53: After starting the HP-RTM press, when the pressure, temperature and vacuum reach the preset second pressure value, second temperature value and second vacuum value respectively, high pressure injection of resin and curing agent is started to form the rim. The second pressure value, second temperature value and second vacuum value are all equal to the first pressure value, first temperature value and first vacuum value. The HP-RTM molding of the outer body 3 is similar to the HP-RTM molding of the lower body 2, and will not be described in detail here.

[0081] S54: After the resin and the curing agent are cured, the rim is removed from the mold.

[0082] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightweight rim, characterized in that: It comprises an upper body, a lower body, a thickened body group and an outer body; the upper body, the lower body and the thickened body group are connected to form a combined body, and the outer body is wrapped outside the combined body; The upper body is formed by laying and compression molding of prepreg; the thickened body group is made of polyurethane foam; the lower body and the outer body are formed by combining three-dimensional weaving technology with HP-RTM molding process.

2. The lightweight rim according to claim 1, characterized in that: The thickened body group includes at least five thickened bodies.

3. The lightweight rim according to claim 2, characterized in that: The five thickened bodies are respectively a first thickened body, a second thickened body, a third thickened body, a fourth thickened body and a fifth thickened body.

4. The lightweight rim according to claim 3, characterized in that: The first thickened body, the second thickened body, and the third thickened body are located between the upper body and the outer body; the fourth thickened body and the fifth thickened body are located between the lower body and the outer body.

5. An efficient production method for a lightweight rim, used for producing the lightweight rim according to any one of claims 1 to 4, characterized in that: The specific steps are as follows: S1: forming the upper body by using a prepreg lay-up compression molding process; S2: preparing a polyurethane composition liquid and injecting it into a polyurethane mold to form a hard polyurethane foam; then, machining the polyurethane foams respectively through mechanical processing to respectively add five thickening bodies of the thickening body group; S3: firstly, a lower body preform is made by using a three-dimensional weaving technology, and then, a HP-RTM molding process is used to form the lower body; S4: connecting the formed upper body, the thickened body group and the lower body into a combined body; S5: First, a three-dimensional weaving technology is used on the combination to form an external integral preform, and then an HP-RTM molding process is used to form the external integral body, and finally a lightweight rim is made.

6. The efficient production method of lightweight rim according to claim 5, characterized in that: The specific steps of upper body forming in step S1 are as follows: S11: making the prepreg into a fan-shaped sample and laying it into a ring-shaped plate; S12: applying a release agent to the inner surface of the upper body mold, and preheating the upper body mold to a first preset temperature; placing the annular plate on the upper body mold, closing the molds for compression molding, and forming an uncured upper body; S13: curing the uncured upper body at a second preset temperature and a first preset time, and taking out the upper body after curing.

7. The efficient production method of lightweight rim according to claim 5, characterized in that: The specific steps of thickening the body component in step S2 are as follows: S21: mixing the polyurethane raw material, the catalyst and the stabilizer in a predetermined ratio to form a polyurethane composite material; during the mixing of the polyurethane composite material, preheating the polyurethane mold to a third preset temperature, and applying a release agent on the surface of the polyurethane mold; S22: injecting the polyurethane composition mixed in step S21 into the polyurethane mold for chemical reaction, and forming a hard polyurethane foam after curing; S23: The rigid polyurethane foam is processed into five thickened bodies of the thickened body group through mechanical processing.

8. The efficient production method of lightweight rim according to claim 5, characterized in that: The specific steps of the lower body forming in step S3 are as follows: S31: constructing a lower body preform mold, and determining a unit cell thickness of the lower body according to the fiber volume content of the lower body; S32: Determine the unit cell as the smallest preform unit, and realize the spatial orientation of the fiber bundle by controlling the movement of the yarn of the fiber bundle in four directions; S33: During the weaving process, for the gradually thickening area of ​​the cross section of the lower body, the number of rows of yarns is first guided, and then the reverse yarns are filled in sequence; for the cone area of ​​the longitudinal section of the lower body, a weaving method from the large end to the small end is adopted; finally, the four-step weaving method is continued until the weaving of the lower body preform is completed; S34: placing the braided lower body preform on a mold of a HP-RTM press; S35: After the HP-RTM press is started, when the pressure, temperature and vacuum degree reach a preset first pressure value, a first temperature value and a first vacuum degree value respectively, high-pressure injection of resin and curing agent is started to form an uncured lower body; S36: After the uncured lower body is cured, demoulding and taking out the lower body.

9. The efficient production method of lightweight rim according to claim 5, characterized in that: The specific steps of connecting the upper body, the thickened body group and the lower body into a combined body in step S4 are as follows: S41: connecting the formed upper body and the lower body by screws, and gluing them at the connection points with glue to ensure that the upper body and the lower body are combined into one body; S42: Each thickened body in the thickened body group is glued to the corresponding preset position of the upper body and the lower body to form a combined body.

10. The efficient production method of lightweight rim according to claim 5, characterized in that: The specific steps of the external integral forming in step S5 are as follows: S51: Weaving an external integral preform on the assembly using a four-step three-dimensional weaving technology; S52: placing the outer integral preform on the HP-RTM press; S53: After the HP-RTM press is started, when the pressure, temperature and vacuum degree reach a preset second pressure value, a second temperature value and a second vacuum degree value respectively, high-pressure injection of resin and curing agent is started to form the rim; S54: After the resin and the curing agent are cured, the rim is removed from the mold.

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