Automotive composite connecting rod mold and manufacturing control method based on thermal expansion forming

Abstract

The present invention proposes a composite connecting rod mold for automobiles and a manufacturing control method based on thermal expansion forming. The composite connecting rod mold for automobiles is made of 6061 aluminum alloy, and a parting surface is established at the rounded contour line on the upper surface of the inner cavity of the mold; the upper mold is designed as a three-section clamping module to improve the clamping efficiency and the molding quality of the connecting rod end; the outer ends of the inner cavity rings of the upper mold and the lower mold are provided with thermal expansion foam placement grooves to avoid the bending and deformation of the fibers at the end of the connecting rod and ensure the mechanical properties of the rod. A three-dimensional lifting module is embedded in the parting surface of the lower mold, while avoiding the inner cavity of the upper mold, ensuring the demoulding efficiency while preventing glue overflow and blockage. The mold of the present invention is suitable for the preparation of composite special-shaped pipe structures by thermal expansion forming process, which effectively solves the problems of mold removal and clamping difficulties, glue overflow and molding quality of existing molds in the preparation process.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile connecting rod manufacturing dies, in particular to an automobile composite connecting rod die based on thermal expansion molding and a manufacturing control method. Background Art

[0002] With the continuous increase in the global vehicle population, energy shortages and environmental pollution are becoming increasingly prominent. Vehicle lightweighting can significantly reduce energy consumption and environmental pollution, effectively extend the service life of key components, and enhance vehicle comfort and safety. Therefore, it has become a key development trend in the current automotive industry and a key strategy for improving fuel economy, reducing emissions, and enhancing overall performance. Carbon fiber composites are widely used in automotive manufacturing due to their advantages such as lightweight, high strength, high rigidity, and corrosion resistance. Composite connecting rods, as a core component of chassis systems, are a key breakthrough in achieving vehicle lightweighting. Compared with traditional metal connecting rods, composite connecting rods not only significantly reduce weight but also improve vibration and noise characteristics, while also enhancing durability and thermal performance. Therefore, the development of mold technology is crucial to achieving large-scale manufacturing of composite connecting rods. Currently, mold design for composite connecting rods primarily targets high precision, high efficiency, and high reliability, while also adapting to complex geometries and diverse molding processes.

[0003] However, there is no precedent for using composite materials to make connecting rods. Due to the lack of a simple and efficient preparation process and the limited number of corresponding composite material preparation molds, traditional molds are not suitable for the thermal expansion molding process and the preparation of composite material special-shaped pipe structures. This is a technical gap in the lightweighting of automotive connecting rods. Due to the anisotropy of carbon fiber composite materials and the thermal expansion characteristics of thermal expansion material extrusion prepreg molding, traditional connecting rod molds are prone to product warping, dimensional deviation or surface quality problems, and need to work under high temperature and high pressure conditions. The compatibility and process stability between traditional molds and carbon fiber composite materials are poor, making the molds susceptible to wear, thermal shock and chemical corrosion during high-frequency and high-pressure molding. At the same time, the insufficient temperature control accuracy of the mold directly affects the quality of the connecting rod product and production efficiency. The above pain points make it difficult for traditional molds to accurately and quickly perform thermal expansion molding of carbon fiber composite connecting rods, which cannot meet market demand. Summary of the Invention

[0004] The present invention overcomes the shortcomings of the prior art and provides a composite connecting rod mold for an automobile based on thermal expansion molding and a manufacturing control method.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a composite connecting rod mold for a vehicle based on thermal expansion molding, wherein the composite connecting rod mold for a vehicle comprises an upper mold and a lower mold:

[0007] The upper and lower molds are made of 6061 aluminum alloy, and the parting surface between the upper and lower molds is established at the contour line of the fillet on the upper surface of the inner cavity, so that the mold can be assembled and disassembled more conveniently and quickly during the thermal expansion manufacturing process of the connecting rod;

[0008] The upper mold is configured as three clamping modules, including a first-stage clamping module, a second-stage clamping module, and a third-stage clamping module. The dividing line of the three clamping modules is at a diameter perpendicular to the forming direction of the end metal ring, and the three clamping modules are tightly connected without gaps.

[0009] The lower die is provided with two metal ring positioning truncated cones, the diameter of the lower bottom surface of the metal ring positioning truncated cone is the inner diameter of the metal ring, the diameter of the upper bottom surface is slightly smaller than the diameter of the lower bottom surface, and the height is the height of the metal ring;

[0010] A heat expansion foam placement groove is provided at both ends of the inner cavity of the upper mold and the lower mold. The heat expansion foam placement groove is opened at the outer periphery of the end of the connecting rod outline and communicates with the inner cavity for placing the heat expansion foam. The depth of the heat expansion foam placement groove is set to the thickness required for the heat expansion foam to be offset outward from both ends of the inner cavity after expansion.

[0011] Four inlay grooves are provided on the parting surface of the lower mold, and the four inlay grooves are provided on both sides of the parting surface of the lower mold and are symmetrically distributed. Each of the inlay grooves is embedded with a three-dimensional lifting module, and the three-dimensional lifting module is provided with a stepped groove. The stepped groove ensures that the three-dimensional lifting module does not interfere with the rounded corners of the upper mold cavity when embedded in the parting surface of the lower mold.

[0012] Furthermore, in a preferred embodiment of the present invention, two locating pin slots are opened at the bottom of the parting surface of the upper mold, and the two locating pin slots are used to nest locating pins of matching specifications respectively. The two locating pins are fixed on the parting surface of the lower mold, and the two locating pins are arranged in a diagonal form.

[0013] Furthermore, in a preferred embodiment of the present invention, the inlay groove and the three-dimensional lifting module are clearance-fitted, a φ10 threaded hole is provided in the middle of the three-dimensional lifting module, and the mold is removed by screwing in a bolt, and the three-dimensional lifting module has a trapezoidal cross-section shape that is wide at the top and narrow at the bottom, and is higher than the parting surface of the lower mold to the upper mold groove, and each of the three-dimensional lifting modules is clearance-fitted with the upper mold groove while avoiding the inner cavity part of the upper mold.

[0014] Furthermore, in a preferred embodiment of the present invention, a hexagonal countersunk hole is provided on the parting surface of the lower mold, and the hexagonal countersunk hole is used to fix the head of the bolt. The upper mold and the lower mold are provided with positioning and fastening through holes, so that the entire bolt can pass through, which is convenient for better locking and disassembly of the nut. There are 3 positioning and fastening through holes in the first-stage clamping module and the second-stage clamping module, and 8 positioning and fastening through holes in the third-stage clamping module, totaling 14 positioning and fastening through holes.

[0015] Furthermore, in a preferred embodiment of the present invention, the upper mold is provided with a φ16 demolding threaded hole, and the principle of the demolding threaded hole is the same as that of the three-dimensional demolding module. The upper mold portion is lifted up by screwing in the bolt and touching the parting surface of the lower mold. There are two demolding threaded holes in the first-stage mold module and the second-stage mold module, and they are arranged in parallel. There are also two demolding thread holes in the three-stage mold module, which are arranged diagonally.

[0016] Furthermore, in a preferred embodiment of the present invention, a rectangular overflow glue groove is provided on the parting surface of the lower mold, and the overflow glue groove is opened along both sides of the parting surface of the lower mold, and three overflow glue grooves are opened on each side of the parting surface of the lower mold to ensure that excess epoxy resin can be fully discharged.

[0017] A second aspect of the present invention provides a manufacturing control method for a composite connecting rod mold for an automobile based on thermal expansion forming, which is applied to any of the composite connecting rod molds for an automobile based on thermal expansion forming, and comprises the following steps:

[0018] Obtain the target connecting rod processing requirements and perform thermal expansion forming of the connecting rod based on the target connecting rod processing requirements. During the thermal expansion forming process, the thermal expansion parameters of the composite connecting rod mold are calculated using finite element calculation software to construct a thermal expansion forming finite element model of the composite material;

[0019] The structural working condition model and thermal stress cloud map of the composite material during heating are extracted through the thermal expansion forming finite element model. The deformation parts of the composite material during heating and the ultimate deformation load of each deformation part are extracted based on the structural working condition model.

[0020] Obtaining an actual heating temperature gradient output by the composite connecting rod mold during the continuous heating process, segmenting the thermal stress cloud map during the composite heating process into N sub-cloud blocks based on the actual heating temperature gradient, constructing a Laplace matrix of each sub-cloud block located in the structural working condition model, and calculating the eigenvectors within the Laplace matrix and the eigenvalues ​​of each eigenvector;

[0021] According to the preset characteristic threshold of the extreme deformation load of each deformation part, only the sub-cloud blocks corresponding to the eigenvectors with eigenvalues ​​less than the characteristic threshold are extracted to construct a new Laplace matrix. Then, deformation clustering is performed on each row of the sub-cloud blocks of this new Laplace matrix based on the extreme deformation load.

[0022] After deformation clustering is completed, clustering results of thermal stress associated with deformation parts are generated. By analyzing the clustering results, the stress-deformation law of the composite material under the heating temperature gradient is determined. Based on the stress-deformation law, the temperature parameters of the composite material thermal expansion molding during the manufacturing process of the composite material connecting rod mold are intelligently controlled.

[0023] Furthermore, in a preferred embodiment of the present invention, the following steps are also included:

[0024] Obtaining predetermined thermal expansion forming working conditions of the composite connecting rod mold under different preset connecting rod processing requirements, and constructing a connecting rod processing and forming system for the composite connecting rod mold according to the predetermined thermal expansion forming working conditions;

[0025] Calculate the similarity between the target connecting rod processing requirements and different preset connecting rod processing requirements one by one, extract the connecting rod processing and forming system corresponding to the preset connecting rod processing requirement with the maximum similarity, and define it as the target connecting rod processing and forming system for the target connecting rod processing requirement;

[0026] A finite element mechanical model of a steel connecting rod that meets the processing requirements of the target connecting rod is obtained based on a big data network, and the maximum stress value, maximum displacement deformation, and natural frequency of the steel connecting rod under different working conditions are extracted from the finite element mechanical model of the steel connecting rod using finite element calculation software;

[0027] Determining, based on the maximum stress value, maximum displacement deformation, and natural frequency, baseline initial performance indicators that the composite material thermal expansion should follow when the composite material connecting rod mold meets the target connecting rod processing requirements; wherein the baseline initial performance indicators include structural strength, stiffness, and vibration characteristics;

[0028] Obtaining the index threshold value specified for each benchmark initial performance index in the target connecting rod processing requirements, and constructing a standard composite connecting rod model according to the index threshold value specified for each benchmark initial performance index;

[0029] By thermal expansion forming discrete combinations of composite materials with different resin matrix material types and fiber types, the simulated thermal expansion characteristic radar chart of each discrete combination of composite materials after simulated thermal expansion processing is fitted, and each simulated thermal expansion characteristic radar chart is compared with the thermal expansion characteristic radar chart of the standard composite connecting rod model for thermal expansion material selection analysis to obtain alternative composite material selection schemes.

[0030] Furthermore, in a preferred embodiment of the present invention, the discrete combinations of composite materials formed by thermal expansion molding different resin matrix material types and fiber types, fitting a simulated thermal expansion characteristic radar chart of each discrete combination of composite materials after simulated thermal expansion processing, and performing a thermal expansion material selection analysis on each simulated thermal expansion characteristic radar chart and a thermal expansion characteristic radar chart of a standard composite connecting rod model to obtain an alternative composite material selection scheme specifically includes the following steps:

[0031] Based on the big data network, the types of resin matrix materials and fibers that can be used to manufacture connecting rods in composite connecting rod molds are obtained. Based on the prepreg process flow, the types of resin matrix materials and fibers are discretely combined to obtain discrete combinations of composite materials that can be thermally expanded.

[0032] Constructing a radar chart, performing a simulated thermal expansion process on each discrete combination of composite materials using a target connecting rod processing and forming system to obtain a thermal expansion characteristic index of each discrete combination of composite materials, and generating a simulated thermal expansion characteristic radar chart of each discrete combination of composite materials based on the radar chart thermal expansion characteristic index;

[0033] Obtain an optimal thermal expansion characteristic radar map when conforming to a standard composite connecting rod model, align the optimal thermal expansion characteristic radar map with each simulated thermal expansion characteristic radar map, and calculate the radar area deviation between the simulated thermal expansion characteristic radar map and the optimal thermal expansion characteristic radar map one by one;

[0034] If the radar area deviation is less than the preset radar area deviation, the discrete combination of composite materials corresponding to the simulated thermal expansion characteristic radar diagram under the radar area deviation is extracted and marked as an alternative composite material selection scheme.

[0035] Upload all the extracted one or more groups of candidate composite material selection solutions to the manufacturing material selection terminal of the composite connecting rod mold.

[0036] Furthermore, in a preferred embodiment of the present invention, the following steps are also included:

[0037] Acquiring actual temperature data of the composite material during a thermal expansion forming process and the distribution points of each actual temperature data, constructing a thermal map, and fitting and plotting each actual temperature data on the thermal map based on the distribution points to generate an actual temperature thermal distribution map of the composite material during the thermal expansion forming process;

[0038] The Hamiltonian method is introduced. The Hamiltonian function is constructed by the Hamiltonian method on the actual temperature and thermal distribution diagram output by the finite element model of thermal expansion forming of composite materials. The Hamiltonian canonical equation is obtained. The Hamiltonian canonical equation is solved and the dynamic behavior description is performed to obtain the dynamic color gamut change distribution model of the actual temperature and thermal force.

[0039] Obtaining a preset temperature control strategy for the composite material, and dividing the dynamic color gamut distribution change model of the actual temperature thermal force into M sub-model regions based on the preset temperature control strategy;

[0040] The color gamut coding rules for temperature and thermal expression are obtained through a big data network. Based on the color gamut coding rules, the temperature and thermal color gamut change coding is read and written when a composite connecting rod mold is manufactured using the optimal thermal expansion characteristic radar chart as a benchmark. This generates a temperature and thermal color gamut distribution change query table.

[0041] Obtaining a current color gamut distribution change code set for each sub-model region; if any current code in the current color gamut distribution change code set can be found in the color gamut distribution change query table, marking the sub-model region as a reasonable temperature control model region;

[0042] If any current code in the current color gamut distribution change code set cannot be found in the color gamut distribution change query table, the sub-model area is marked as an unreasonable temperature control model area, and finally a model color gamut pattern diagram of the unreasonable temperature control model area is obtained;

[0043] The heating rate, cooling rate and thermal expansion process parameters of composite material thermal expansion forming during the manufacturing process of composite material connecting rod mold are controlled based on the model color gamut pattern diagram.

[0044] The beneficial technical effects of the present invention are:

[0045] The overall shape of the mold of the present invention fits closely with the contour of the connecting rod, and the thickness of the upper and lower molds is evenly distributed, which effectively improves the heat transfer efficiency and reduces the influence of temperature gradients. The "three-stage" upper mold structure, symmetrically distributed demolding threaded holes and meticulous parting surface design ensure that the mold improves the loading and unloading efficiency while ensuring the quality of the rod ends and the overall molding. The thermal expansion foam design ensures the uniform molding of the prepreg, especially the shape and surface quality of complex areas. The narrow bottom and wide top design of the three-dimensional demolding module and the stepped groove design facilitate loading and unloading, effectively avoiding interference and damage to the rods and molds. The uniform distribution of 8 bolts in the middle of the mold and 3 bolts on each of the left and right parts not only effectively improves the tightness of the mold, but also achieves uniform force on the entire mold, reducing deformation caused by local stress concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0047] Figure 1 This is a schematic diagram of the upper and lower mold structures of this mold;

[0048] Figure 2 This is a schematic diagram of the three-section structure of the upper mold of this mold;

[0049] Figure 3 Schematic diagram of the lower mold structure of this mold

[0050] Figure 4 for Figure 3 Schematic diagram of the foam placement groove structure of the middle AA lower mold;

[0051] Figure 5 Schematic diagram of the die-cutting thread hole structure of the upper die;

[0052] Figure 6 It is the overall structure and installation diagram of the three-dimensional module;

[0053] Figure 7 Schematic diagram of the glue overflow groove structure of the lower mold.

[0054] The following are the descriptions of the reference numerals:

[0055] 101. Upper mold; 102. Lower mold; 103. Parting surface; 104. Inner cavity; 105. One-stage clamping module; 106. Two-stage clamping module; 107. Three-stage clamping module; 108. Foam placement groove; 109. Three-dimensional lifting module; 201. Step groove; 202. Locating pin; 203. Positioning and fastening through hole; 204. Demolding threaded hole; 205. Glue overflow groove. DETAILED DESCRIPTION

[0056] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner. Therefore, they only show the structures related to the present invention. It should be noted that, unless there is a conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0057] In the description of the present application, 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 orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 limiting the scope of protection of the present application. 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 the indicated technical features. Therefore, 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.

[0058] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0059] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0060] like Figure 1-6 As shown, the first aspect of the present invention provides a composite connecting rod mold for a vehicle based on thermal expansion molding, and the composite connecting rod mold for a vehicle includes an upper mold 101 and a lower mold 102 .

[0061] The upper mold 101 and the lower mold 102 are made of 6061 aluminum alloy. The parting surface 103 between the upper mold 101 and the lower mold 102 is established based on the contour line of the rounded corner of the upper surface of the connecting rod in the inner cavity 104 based on the shape of the connecting rod, so that the mold can be assembled and disassembled more conveniently and quickly during the thermal expansion manufacturing process of the connecting rod.

[0062] It should be noted that compared to traditional steel molds, the density of aluminum alloy is only one-third of that of steel. The present invention significantly reduces weight by using 6061 aluminum alloy for high-speed cutting to make molds. During use, the opening and closing speed of the mold made of lightweight aluminum alloy can be significantly increased, and portability is enhanced. This makes the transportation and operation of aluminum alloy parts more convenient and quick, and production efficiency is greatly improved. On the one hand, the thermal conductivity of aluminum alloy is four times that of steel. Therefore, the use of aluminum alloy material can significantly shorten the cooling time of the mold, eliminating the need for a complex cooling system. At the same time, aluminum alloy has a fast and uniform heat dissipation effect, which can effectively reduce the residual stress and warping deformation caused by uneven cooling inside the plastic product. On the other hand, the electrical conductivity of aluminum alloy is 10 times that of traditional steel, which makes its EDM efficiency 4 to 5 times that of steel, further effectively reducing the processing cost of the mold material. Therefore, the use of aluminum alloy mold material in the present invention can optimize the process performance of the mold itself design and processing, and can also greatly improve the thermal conductivity and electrical conductivity during thermal expansion processing. Since aluminum alloys can cut at speeds over five times that of steel, mold processing time can be significantly reduced. This effectively shortens the cycle from mold design to mass production, allowing mold products to be quickly put on the market. Furthermore, aluminum alloys' unique and excellent processing properties can significantly reduce tool wear and tear, helping to extend tool life. In summary, aluminum alloys offer advantages such as excellent welding performance, good machinability, and a short production cycle, which can improve the quality and efficiency of mold mass production.

[0063] It should be noted that the overall mold shape of the present invention is consistent with the contour of the connecting rod, and has a high degree of compatibility with the form-fitting design. It can reduce the thermal expansion waste of the composite material and improve the processing accuracy through the optimized curve structure, ensuring the uniformity of pressure and heat conduction during processing or use, making the assembly of the mold more rational; and the thickness of the mold circumference and the upper mold 101 and the lower mold 102 are in line with the standard tolerance range, so that they remain uniform, ensuring the feasibility and performance stability of the thermal expansion manufacturing of the composite material in the mold, which is conducive to improving heat transfer efficiency and minimizing the impact of temperature gradients. At the same time, the parting surface 103 is established on the contour line of the rounded corner of the upper surface of the connecting rod of the inner cavity 104 to avoid the prepreg being squeezed and wrinkled when the mold is closed.

[0064] The upper mold is configured as three clamping modules, which include a first-stage clamping module 105, a second-stage clamping module 106, and a third-stage clamping module 107. The dividing line of the three clamping modules is at a diameter perpendicular to the forming direction of the end metal ring. The three clamping modules are tightly connected without gaps.

[0065] The lower die 102 is provided with two metal ring positioning cones, the lower bottom surface diameter of the metal ring positioning cone is the inner diameter of the metal ring, the upper bottom surface diameter is slightly smaller than the lower bottom surface diameter, and the height is the height of the metal ring.

[0066] It should be noted that during the mold closing process, the three-stage mold closing module 107 is normally closed from top to bottom, and is mainly responsible for the main forming area of ​​the connecting rod, while the one-stage mold closing module 105 and the two-stage mold closing module 106 are slowly pushed in horizontally from both sides, focusing on the stable pressing of the connecting rod end. This mold closing method can distribute pressure more accurately and reduce the stress concentration phenomenon of thermal expansion molding. At the same time, the mold closing method design helps to simplify the mold closing operation process, and is especially suitable for scenes with complex shapes or materials that require high pressing accuracy. It is convenient for fast mold closing and reduces wrinkles or bubbles caused by improper mold closing on the prepreg on the rod. The three-stage mold closing design can realize detailed operations in multiple directions, improve the mold closing rate, and make the mold pressure distribution more uniform, especially for the detailed molding of the connecting rod end, avoiding burrs or deformations that may occur on the connecting rod end with conventional molds.

[0067] A heat expansion foam placement groove 108 is provided at the connection between the two ends of the inner cavity 104 of the upper mold 101 and the lower mold 102 and the middle part of the inner cavity 104. The heat expansion foam placement groove 108 is opened on the periphery of the end of the connecting rod outer contour of the inner cavity 104 and is communicated with the inner cavity 104 for placing heat expansion foam. The depth of the heat expansion foam placement groove 108 is set to the thickness of the heat expansion foam after expansion, which is offset outward from the two ends of the inner cavity 104.

[0068] It should be noted that the provision of thermal expansion foam placement groove 108 enables prepreg molding at the end of the connecting rod during the thermal expansion molding process. This mold is offset by 2.25 cm. The precise 2.25 cm dimension is due to the need to place three layers of external thermal expansion foam, with a single layer being 0.5 mm. After the expected expansion of 1.5 times, it will assume a 2.25 mm shape. Therefore, a 2.25 cm thermal expansion foam placement groove is created to provide a stable space for the thermal expansion foam. It is important to note that in the middle of the connecting rod, the thermal expansion foam is internal, but the thermal expansion foam placement groove is located within the metal ring. At this point, the thermal expansion foam on the metal ring is positioned at the outermost portion, i.e., within the thermal expansion foam placement groove. After molding is completed, the thermal expansion foam will be removed, leaving only the carbon fiber composite material outside the metal ring at the end of the connecting rod. This is intended to increase tensile stiffness and reduce dimensional constraints outside the ring. The 2.25mm size of the thermal expansion foam placement groove is based on the fact that the thermal expansion foam has a size of 2.25mm after expansion. This setting effectively reduces the fiber buckling deformation problem caused by the thermal expansion foam being inside the bottom of the connecting rod and the thermal expansion foam being outside the metal ring at the end, making the overall appearance of the connecting rod smoother. It prevents movement during heating or pressurization, thereby improving the molding accuracy of the prepreg. In the complex structural area at the end of the connecting rod, the additional expansion foam pressure can optimize the fit of the composite fiber layer and improve the surface quality after molding. Therefore, the thermal expansion foam placement groove 108 can provide additional temperature increase expansion pressure and shape support on the one hand, ensuring the uniform distribution of the prepreg in the inner cavity 104; on the other hand, it can better adapt to the thickness change of the connecting rod end, avoiding material damage or deformation due to uneven pressure distribution when the mold is closed.

[0069] Four inlay grooves are provided on the parting surface 103 of the lower mold 102. The four inlay grooves are provided on both sides of the lower mold parting surface 103 and are symmetrically distributed. Each of the inlay grooves is embedded with a three-dimensional lifting module 109. The three-dimensional lifting module 109 is provided with a stepped groove 201. The stepped groove 201 ensures that the three-dimensional lifting module 109 does not interfere with the radius of the cavity of the upper mold 101 when it is embedded in the parting surface 103 of the lower mold 102.

[0070] The inlay groove and the three-dimensional lifting module 109 are clearance-fitted. A φ10 threaded hole is provided in the middle of the three-dimensional lifting module 109, and the demoulding is performed by screwing in a bolt. The three-dimensional lifting module 109 has a trapezoidal cross-section shape that is wide at the top and narrow at the bottom, and is higher than the parting surface 103 of the lower mold 102 to the upper mold groove. Each of the three-dimensional lifting modules 109 is clearance-fitted with the upper mold groove, while avoiding the inner cavity 102 part of the upper mold 101.

[0071] It should be noted that the overall shape of the three-dimensional lifting module 109 fits closely with the lower mold to ensure the molding quality of the connecting rod. Its design of being wide at the top and narrow at the bottom can avoid the jamming of the mold and the workpiece during demolding, which is conducive to stable loading and unloading; and its design of being higher than the parting surface 103 of the lower mold 102 to the upper mold 101 can prevent excess resin material from flowing into the threaded hole and causing blockage, avoid demolding difficulties, and reduce the complexity of subsequent cleaning work. The clearance fit design ensures that the three-dimensional lifting module can be quickly disassembled to prevent mutual interference, and also maintains the positioning accuracy of the three-dimensional lifting module 109, reducing molding errors. The stepped groove 201 design can prevent the interference between the three-dimensional lifting module 109 and the fillet of the inner cavity 104 of the upper mold 101, which causes defects in the shape of the connecting rod, ensure the integrity of the connecting rod molding, and help improve the surface smoothness of the connecting rod parts. The four three-dimensional lifting modules 109 are symmetrically distributed on both sides of the mold. When the bolts are screwed into the threaded holes on them to lift the three-dimensional lifting modules 109 themselves, the rods are evenly stressed, which can make the force transmission during the demolding process more stable without damaging the rods, and help extend the service life of the mold.

[0072] Two locating pin slots are provided at the bottom of the parting surface 103 of the upper mold 101. The two locating pin slots are used to respectively nest locating pins 202 of the same specifications. The two locating pins 202 are fixed on the parting surface 103 of the lower mold 102, and the two locating pins 202 are arranged diagonally.

[0073] It should be noted that when closing the mold, the locating pins on the parting surface 103 of the lower mold 102 are aligned with the locating pin slots on the parting surface 103 of the upper mold 101 and inserted into the positioning assembly. The locating pins 202 are precisely sized and shaped, and are tightened on the top and loosened on the bottom, i.e., they are clearance fit relative to the upper mold and interference fit relative to the lower mold, to ensure the position accuracy of the rod during assembly or processing. This is particularly important for high-precision processing and assembly, and can guarantee the quality and performance of the final product. The use of the locating pins 202 can greatly reduce the time for positioning and adjustment, and it can enable the rod to reach the desired position quickly and accurately, thereby improving the efficiency of closing the mold. In addition, if the position of the rod is inaccurate during the assembly process, it may cause damage to the mold or deformation of the rod. The locating pins 202 can ensure the accurate position of the rod, thereby protecting the mold and the rod from damage, and greatly reducing the cost of frequent replacement and maintenance of the mold. At the same time, the use of the locating pins 202 makes the assembly and processing process simpler and more intuitive, and can reduce the operational difficulty and skill requirements of connecting rod injection molding.

[0074] A hexagonal countersunk hole is provided on the parting surface 103 of the lower mold 102, and the hexagonal countersunk hole is used to fix the head of the clamping bolt. The upper mold 101 and the lower mold 102 are provided with a positioning and fastening through hole 203, so that the entire bolt can pass through, which is convenient for better locking and removing the nut.

[0075] Three positioning and fastening through holes 203 are provided in the first-stage mold clamping module 105 and the second-stage mold clamping module 106 , and eight are provided in the third-stage mold clamping module 107 , for a total of 14 positioning and fastening through holes 203 .

[0076] It should be noted that the eight positioning and fastening holes 203 provided in the three-stage clamping module 107 are mainly used to fix the stress-bearing area of ​​the mold, helping to control the pressure distribution in the middle and avoid warping or demolding problems in the middle. The three positioning and fastening holes 203 provided in the first-stage clamping module 105 and the second-stage clamping module 106 respectively can evenly distribute the pressure on both sides, optimize the pressure transmission at the ends of the mold, and reduce material defects caused by local uneven stress. The uniform arrangement of the 14 positioning and fastening holes 203 on the mold can make the mold clamp more tightly, which is conducive to improving the molding quality of the rod.

[0077] The upper mold 101 is provided with a φ16 demolding threaded hole 204. The demolding threaded hole 204 has a similar function to the three-dimensional demolding module 109. By screwing in the bolt and touching the parting surface 103 of the lower mold 102, the upper mold 101 is partially lifted up. There are two demolding threaded holes 204 on the part of the first-stage mold clamping module 105 and the part of the second-stage mold clamping module 106, and they are arranged in parallel; there are also two on the part of the three-stage mold clamping module 107, which are arranged diagonally.

[0078] It should be noted that by screwing the bolt into the demolding threaded hole 204, when the end of the bolt touches the lower mold 102 and continues to screw it in, the upper mold 101 will be gradually lifted up, thereby avoiding the greater impact caused by direct prying and demolding, thereby achieving the purpose of protecting the mold, and when the bolt is screwed into the demolding threaded hole 204 to lift the upper mold 101, the force is evenly distributed, which helps to prevent mold deformation or rod damage caused by excessive local stress.

[0079] The parting surface 103 of the lower mold 102 is provided with rectangular overflow grooves 205. The overflow grooves 205 are opened along both sides of the parting surface 103 of the lower mold 102, and three overflow grooves are opened on each side along the parting surface 103 of the lower mold 102 to ensure that excess epoxy resin can be fully discharged.

[0080] It should be noted that during the thermal expansion molding process, epoxy resin can overflow from the prepreg and thermal expansion foam. If not promptly removed, this can lead to excessive resin content between prepreg layers, resulting in localized resin accumulation in the rod, loose interlayers, and reduced interfacial bonding. Therefore, to improve the quality of the rod thermal expansion molding process, excess epoxy resin should be removed from the inner cavity 104 as much as possible. This is accomplished by providing an overflow groove 205. To more effectively implement the function of the overflow groove 205, this mold is located on the parting surface of the lower mold, ensuring that the product is filled with resin while also balancing pressure.

[0081] A second aspect of the present invention provides a manufacturing control method for a composite connecting rod mold for an automobile based on thermal expansion forming, which is applied to any of the composite connecting rod molds for an automobile based on thermal expansion forming, and comprises the following steps:

[0082] Obtain the target connecting rod processing requirements and perform thermal expansion forming of the connecting rod based on the target connecting rod processing requirements. During the thermal expansion forming process, the thermal expansion parameters of the composite connecting rod mold are calculated using finite element calculation software to construct a thermal expansion forming finite element model of the composite material;

[0083] The structural working condition model and thermal stress cloud map of the composite material during heating are extracted through the thermal expansion forming finite element model. The deformation parts of the composite material during heating and the ultimate deformation load of each deformation part are extracted based on the structural working condition model.

[0084] Obtaining an actual heating temperature gradient output by the composite connecting rod mold during the continuous heating process, segmenting the thermal stress cloud map during the composite heating process into N sub-cloud blocks based on the actual heating temperature gradient, constructing a Laplace matrix of each sub-cloud block located in the structural working condition model, and calculating the eigenvectors within the Laplace matrix and the eigenvalues ​​of each eigenvector;

[0085] According to the preset characteristic threshold of the extreme deformation load of each deformation part, only the sub-cloud blocks corresponding to the eigenvectors with eigenvalues ​​less than the characteristic threshold are extracted to construct a new Laplace matrix. Then, deformation clustering is performed on each row of the sub-cloud blocks of this new Laplace matrix based on the extreme deformation load.

[0086] After deformation clustering is completed, clustering results of thermal stress associated with deformation parts are generated. By analyzing the clustering results, the stress-deformation law of the composite material under the heating temperature gradient is determined. Based on the stress-deformation law, the temperature parameters of the composite material thermal expansion molding during the manufacturing process of the composite material connecting rod mold are intelligently controlled.

[0087] It should be noted that composite materials use reasonable layup characteristics and a reasonable sleeve rod connection structure to cope with the high-intensity deformation load impact that the connecting rod is subjected to during use, which can make the connecting rod less likely to deform. One of the indicators that this mold uses to determine the deformation quality of the connecting rod product is the control of temperature during the manufacturing process. If the temperature control accuracy of this mold during the thermal expansion forming process is low, it may lead to a large error in the forming temperature, causing a significant decrease in the load that the connecting rod can withstand. As a result, the connecting rod is extremely prone to deformation during use, reducing the operating safety of the mechanical transmission system. Therefore, it is necessary to accurately study the deformation law of composite materials at different temperatures during the thermal expansion forming process. To this end, this method uses finite element calculation software to establish a numerical model of composite material thermal expansion forming, namely the composite material thermal expansion forming finite element model. The thermal expansion forming finite element model can clearly show the specific conditions of the thermal stress and deformation of the composite material as the temperature gradient changes during thermal expansion forming. Since thermal stress change is one of the important factors in studying the overall performance of composite materials during heating and cooling processes, the thermal stress cloud generated by temperature change is accurately clustered to the specific locations where deformation occurs during the thermal expansion process of the composite material by clustering the eigenvalues ​​of the Laplace matrix. This can clearly reveal the stress-deformation law of the composite material under the heating temperature gradient. Based on this stress-deformation law, the unreasonable temperature parameters that cause the deformation of the connecting rod composite material can be further traced, thereby enabling precise and intelligent control of the composite material thermal expansion forming temperature parameters during the composite connecting rod mold manufacturing process. This method can be used to study the deformation law of composite materials at different temperatures by establishing a numerical model of thermal expansion forming, and then provide a powerful and reliable parameter control basis for the subsequent manufacturing control of the composite connecting rod mold, thereby achieving precise guidance and control of the manufacturing process, significantly improving the molding quality of the connecting rod, and ensuring the safety and stability of the connecting rod application.

[0088] Furthermore, in a preferred embodiment of the present invention, the following steps are also included:

[0089] Obtaining predetermined thermal expansion forming working conditions of the composite connecting rod mold under different preset connecting rod processing requirements, and constructing a connecting rod processing and forming system for the composite connecting rod mold according to the predetermined thermal expansion forming working conditions;

[0090] Calculate the similarity between the target connecting rod processing requirements and different preset connecting rod processing requirements one by one, extract the connecting rod processing and forming system corresponding to the preset connecting rod processing requirement with the maximum similarity, and define it as the target connecting rod processing and forming system for the target connecting rod processing requirement;

[0091] A finite element mechanical model of a steel connecting rod that meets the processing requirements of the target connecting rod is obtained based on a big data network, and the maximum stress value, maximum displacement deformation, and natural frequency of the steel connecting rod under different working conditions are extracted from the finite element mechanical model of the steel connecting rod using finite element calculation software;

[0092] Determining, based on the maximum stress value, maximum displacement deformation, and natural frequency, baseline initial performance indicators that the composite material thermal expansion should follow when the composite material connecting rod mold meets the target connecting rod processing requirements; wherein the baseline initial performance indicators include structural strength, stiffness, and vibration characteristics;

[0093] Obtaining the index threshold value specified for each benchmark initial performance index in the target connecting rod processing requirements, and constructing a standard composite connecting rod model according to the index threshold value specified for each benchmark initial performance index;

[0094] By thermal expansion forming discrete combinations of composite materials with different resin matrix material types and fiber types, the simulated thermal expansion characteristic radar chart of each discrete combination of composite materials after simulated thermal expansion processing is fitted, and each simulated thermal expansion characteristic radar chart is compared with the thermal expansion characteristic radar chart of the standard composite connecting rod model for thermal expansion material selection analysis to obtain alternative composite material selection schemes.

[0095] It should be noted that the thermal expansion characteristics of composite materials are affected by factors such as the matrix material and fiber type. Therefore, during the manufacturing process, the thermal expansion characteristics of the composite materials used must be thoroughly studied and materials with appropriate thermal expansion characteristics must be selected to control dimensional changes during heating and cooling. Composite structural design cannot simply replace traditional metal materials. Therefore, the selection of composite materials should fully adhere to the relevant performance indicators of traditional steel connecting rod structures to ensure that connecting rods formed using composite materials can meet the load impact requirements of different mechanical strength application scenarios and avoid phenomena such as connecting rod fracture and deformation. Therefore, this method uses a similar method to determine the target connecting rod processing system required for the target connecting rod processing requirements. Then, using the maximum stress values, maximum displacement deformation, and natural frequency under different working conditions contained in the finite element mechanical model of the steel connecting rod, the overall performance of the composite material when the mold achieves the target connecting rod processing system can be further analyzed. This allows the initial benchmark performance indicators for the composite material's thermal expansion to be accurately determined based on the performance of the steel connecting rod, ensuring that the composite material's thermal expansion forming is based on the performance standards of the steel connecting rod. Finally, a simulated thermal expansion process was used to analyze and calculate the difference between the simulated thermal expansion characteristics of composite materials and their optimal thermal expansion characteristics for material selection. This method allows for a thorough thermal expansion analysis of composite materials using the performance indicators of steel connecting rods as a benchmark, enabling the selection of appropriate composite materials for connecting rod manufacturing. This method improves the performance reliability of connecting rod material selection based on traditional metal standards and reduces mechanical transmission anomalies in composite connecting rods. It also reduces the intervention errors associated with traditional manual material selection, reduces the rework rate in connecting rod production, saves labor and material costs, and significantly improves the efficiency of composite material selection.

[0096] Furthermore, in a preferred embodiment of the present invention, the discrete combinations of composite materials formed by thermal expansion molding different resin matrix material types and fiber types, fitting a simulated thermal expansion characteristic radar chart of each discrete combination of composite materials after simulated thermal expansion processing, and performing a thermal expansion material selection analysis on each simulated thermal expansion characteristic radar chart and a thermal expansion characteristic radar chart of a standard composite connecting rod model to obtain an alternative composite material selection scheme specifically includes the following steps:

[0097] Based on the big data network, the types of resin matrix materials and fibers that can be used to manufacture connecting rods in composite connecting rod molds are obtained. Based on the prepreg process flow, the types of resin matrix materials and fibers are discretely combined to obtain discrete combinations of composite materials that can be thermally expanded.

[0098] Constructing a radar chart, performing a simulated thermal expansion process on each discrete combination of composite materials using a target connecting rod processing and forming system to obtain a thermal expansion characteristic index of each discrete combination of composite materials, and generating a simulated thermal expansion characteristic radar chart of each discrete combination of composite materials based on the radar chart thermal expansion characteristic index;

[0099] Obtain an optimal thermal expansion characteristic radar map when conforming to a standard composite connecting rod model, align the optimal thermal expansion characteristic radar map with each simulated thermal expansion characteristic radar map, and calculate the radar area deviation between the simulated thermal expansion characteristic radar map and the optimal thermal expansion characteristic radar map one by one;

[0100] If the radar area deviation is less than the preset radar area deviation, the discrete combination of composite materials corresponding to the simulated thermal expansion characteristic radar diagram under the radar area deviation is extracted and marked as an alternative composite material selection scheme.

[0101] Upload all the extracted one or more groups of candidate composite material selection solutions to the manufacturing material selection terminal of the composite connecting rod mold.

[0102] It should be noted that the manufacture of composite connecting rods is usually designed by laying up a variety of different resin matrix materials and fiber materials. However, there are many types of resin matrix materials and fiber materials that can be used for connecting rod manufacturing, and the thermal expansion characteristics produced by different types of resin matrix materials and fiber materials are also different. Therefore, for the selection of composite materials, it is necessary to conduct thermal expansion screening analysis with the optimal thermal expansion characteristics of the composite materials in the mold as the goal. To this end, this method first designs different layup combinations of resin matrix materials and fiber types that can be used for thermal expansion molding in the mold, that is, discrete combinations of composite materials for thermal expansion molding; then simulates thermal expansion processing of the composite materials of these combined layups to simulate the thermal expansion characteristics of these materials, so as to achieve a rapid approximation and determination of the actual thermal expansion characteristics under different composite material combinations. This process can save the traditional tedious steps of manual thermal expansion testing of each composite material combination one by one, greatly improving material selection efficiency. Next, a radar chart of the optimal thermal expansion characteristics for a standard composite connecting rod model is constructed. This chart serves as an evaluation criterion. Therefore, a composite material combination under simulated thermal expansion characteristics is considered qualified if the thermal expansion characteristic threshold indicated by the chart is exceeded. This means that the radar area deviation is less than the preset radar area deviation. This method replaces the tedious steps of traditional manual material selection, reduces the occurrence of manually selected materials with thermal expansion characteristics that do not meet the optimal mold production requirements, and reduces errors in connecting rod thermal expansion forming, further improving and optimizing connecting rod product quality.

[0103] Furthermore, in a preferred embodiment of the present invention, the following steps are also included:

[0104] Acquiring actual temperature data of the composite material during a thermal expansion forming process and the distribution points of each actual temperature data, constructing a thermal map, and fitting and plotting each actual temperature data on the thermal map based on the distribution points to generate an actual temperature thermal distribution map of the composite material during the thermal expansion forming process;

[0105] The Hamiltonian method is introduced. The Hamiltonian function is constructed by the Hamiltonian method on the actual temperature and thermal distribution diagram output by the finite element model of thermal expansion forming of composite materials. The Hamiltonian canonical equation is obtained. The Hamiltonian canonical equation is solved and the dynamic behavior description is performed to obtain the dynamic color gamut change distribution model of the actual temperature and thermal force.

[0106] Obtaining a preset temperature control strategy for the composite material, and dividing the dynamic color gamut distribution change model of the actual temperature thermal force into M sub-model regions based on the preset temperature control strategy;

[0107] The color gamut coding rules for temperature and thermal expression are obtained through a big data network. Based on the color gamut coding rules, the temperature and thermal color gamut change coding is read and written when a composite connecting rod mold is manufactured using the optimal thermal expansion characteristic radar chart as a benchmark. This generates a temperature and thermal color gamut distribution change query table.

[0108] Obtaining a current color gamut distribution change code set for each sub-model region; if any current code in the current color gamut distribution change code set can be found in the color gamut distribution change query table, marking the sub-model region as a reasonable temperature control model region;

[0109] If any current code in the current color gamut distribution change code set cannot be found in the color gamut distribution change query table, the sub-model area is marked as an unreasonable temperature control model area, and finally a model color gamut pattern diagram of the unreasonable temperature control model area is obtained;

[0110] The heating rate, cooling rate and thermal expansion process parameters of composite material thermal expansion forming during the manufacturing process of composite material connecting rod mold are controlled based on the model color gamut pattern diagram.

[0111] It should be noted that the key to thermal expansion molding lies in controlling the heating and cooling rates and temperature distribution during thermal expansion molding. By optimizing the heating rate, cooling rate, and thermal expansion process during thermal expansion molding, excessive material expansion or contraction can be minimized, thereby ensuring the accuracy and integrity of the connecting rod molding. However, traditional molds do not have the ability to control the heating rate, cooling rate, and thermal expansion process during thermal expansion molding, and there are large control deviations. This results in suboptimal thermal expansion molded connecting rod products, which may suffer from abnormal thermal stress or uneven shrinkage. Therefore, this method constructs an actual temperature thermodynamic distribution map reflecting the temperature magnitude, change, and migration based on the actual temperature data of the composite material during the thermal expansion molding process and the distribution points of each actual temperature data. The Hamiltonian method is then introduced to construct a Hamiltonian function to describe the actual temperature thermodynamic distribution, generating an actual temperature thermodynamic dynamic model expressed as a color gamut change distribution. This model can demonstrate the temperature magnitude and migration distribution of the connecting rod during thermal expansion. Therefore, this model can be used to analyze the rationality of the temperature change and distribution of the connecting rod thermal expansion, and accordingly adjust the heating rate, cooling rate, and thermal expansion process during its manufacturing process.

[0112] It should be noted that this method adopts the color gamut coding rule to construct a temperature and thermal color gamut distribution change query table based on the temperature color gamut change coding when the mold follows the optimal thermal expansion characteristic radar chart to manufacture the connecting rod. Through this query table, it is possible to query and judge whether the actual temperature and thermal color gamut change and migration distribution in the dynamic model are reasonable; if any current code in the current color gamut distribution change code set can be queried in the color gamut distribution change query table, it means that the temperature size and temperature distribution in the connecting rod thermal expansion forming process are reasonable, which represents that the current heating rate, cooling rate and thermal expansion process control are appropriate; if any current code in the current color gamut distribution change code set cannot be queried in the color gamut distribution change query table, it means that the current heating rate, cooling rate is too fast or too slow, and there is improper error behavior in the thermal expansion process control, which may cause abnormal thermal stress or uneven shrinkage, thereby leading to unreasonable temperature size and temperature distribution of the connecting rod composite material. This method can control the heating rate, cooling rate and thermal expansion process parameters of the composite material thermal expansion forming during the manufacturing process of the composite material connecting rod mold, thereby controlling the integrity and reliability of the connecting rod structure during the thermal expansion process, helping the composite material to maintain shape stability during the forming process, reducing performance defects of the connecting rod product, and improving the forming quality.

[0113] The above description of the preferred embodiments of the present invention is provided as a guide, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A composite connecting rod mold for an automobile based on thermal expansion molding, comprising an upper mold and a lower mold, characterized in that: The upper and lower molds are made of 6061 aluminum alloy, and the parting surface between the upper and lower molds is established at the rounded contour line of the upper surface of the inner cavity, so that the mold can be assembled and disassembled more conveniently and quickly during the thermal expansion manufacturing process of the connecting rod; The upper mold is configured as three clamping modules, including a first-stage clamping module, a second-stage clamping module, and a third-stage clamping module. The dividing line of the three clamping modules is at a diameter perpendicular to the forming direction of the end metal ring, and the three clamping modules are tightly connected without gaps. The lower die is provided with two metal ring positioning truncated cones, the diameter of the lower bottom surface of the metal ring positioning truncated cone is the inner diameter of the metal ring, the diameter of the upper bottom surface is slightly smaller than the diameter of the lower bottom surface, and the height is the height of the metal ring; A heat expansion foam placement groove is provided at both ends of the inner cavity of the upper mold and the lower mold. The heat expansion foam placement groove is located outside the end of the connecting rod outer contour and communicates with the inner cavity for placing the heat expansion foam. The depth of the heat expansion foam placement groove is set to the thickness required for the heat expansion foam to be offset outward from both ends of the inner cavity after expansion. Four inlay grooves are provided on the parting surface of the lower mold, and the four inlay grooves are provided on both sides of the parting surface of the lower mold and are symmetrically distributed. Each of the inlay grooves is embedded with a three-dimensional lifting module, and the three-dimensional lifting module is provided with a stepped groove. The stepped groove ensures that the three-dimensional lifting module does not interfere with the rounded corners of the upper mold cavity when embedded in the parting surface of the lower mold.

2. The automotive composite connecting rod mold based on thermal expansion molding according to claim 1, characterized in that: Two locating pin slots are provided at the bottom of the parting surface of the upper mold. The two locating pin slots are used to respectively nest locating pins of matching specifications. The two locating pins are fixed on the parting surface of the lower mold, and the two locating pins are arranged in a diagonal shape.

3. The automotive composite connecting rod mold based on thermal expansion molding according to claim 1, characterized in that: The inlay groove and the three-dimensional lifting module are clearance-fitted. A φ10 threaded hole is provided in the middle of the three-dimensional lifting module, and the mold is removed by screwing in a bolt. The three-dimensional lifting module has a trapezoidal cross-section shape that is wide at the top and narrow at the bottom, and is higher than the parting surface of the lower mold to the upper mold groove. Each of the three-dimensional lifting modules is clearance-fitted with the upper mold groove, while avoiding the inner mold cavity part of the upper mold.

4. The automotive composite connecting rod mold based on thermal expansion molding according to claim 1, characterized in that: A hexagonal countersunk hole is provided on the parting surface of the lower mold, and the hexagonal countersunk hole is used to fix the head of the bolt. The upper mold and the lower mold are provided with positioning and fastening through holes, so that the entire bolt can pass through, which is convenient for better locking and disassembly of the nut. There are 3 positioning and fastening through holes in the first stage clamping module and the second stage clamping module, and 8 in the third stage clamping module, totaling 14 positioning and fastening through holes.

5. The automotive composite connecting rod mold based on thermal expansion molding according to claim 1, characterized in that: The upper mold is provided with a φ16 demoulding threaded hole. The theory of the demoulding threaded hole is the same as that of the three-dimensional demoulding module. The upper mold is partially lifted by screwing in the bolt and touching the parting surface of the lower mold. There are two demoulding threaded holes in the first-stage mold module and the second-stage mold module, and they are arranged in parallel. There are also two demoulding thread holes in the three-stage mold module, which are arranged diagonally.

6. The automotive composite connecting rod mold based on thermal expansion molding according to claim 1, characterized in that: A rectangular overflow glue groove is provided on the parting surface of the lower mold. The overflow glue groove is opened along both sides of the parting surface of the lower mold, and three overflow glue grooves are opened on each side along the parting surface of the lower mold to ensure that excess epoxy resin can be fully discharged.

7. A manufacturing control method for a composite connecting rod mold for a vehicle based on thermal expansion molding, applied to the composite connecting rod mold for a vehicle based on thermal expansion molding according to any one of claims 1 to 6, characterized in that: The steps include: Obtain the target connecting rod processing requirements and perform thermal expansion forming of the connecting rod based on the target connecting rod processing requirements. During the thermal expansion forming process, the thermal expansion parameters of the composite connecting rod mold are calculated using finite element calculation software to construct a thermal expansion forming finite element model of the composite material; The structural working condition model and thermal stress cloud map of the composite material during heating are extracted through the thermal expansion forming finite element model. The deformation parts of the composite material during heating and the ultimate deformation load of each deformation part are extracted based on the structural working condition model. Obtaining an actual heating temperature gradient output by the composite connecting rod mold during the continuous heating process, segmenting the thermal stress cloud map during the composite heating process into N sub-cloud blocks based on the actual heating temperature gradient, constructing a Laplace matrix of each sub-cloud block located in the structural working condition model, and calculating the eigenvectors within the Laplace matrix and the eigenvalues ​​of each eigenvector; According to the preset characteristic threshold of the extreme deformation load of each deformation part, only the sub-cloud blocks corresponding to the eigenvectors with eigenvalues ​​less than the characteristic threshold are extracted to construct a new Laplace matrix. Then, deformation clustering is performed on each row of the sub-cloud blocks of this new Laplace matrix based on the extreme deformation load. After deformation clustering is completed, clustering results of thermal stress associated with deformation parts are generated. By analyzing the clustering results, the stress-deformation law of the composite material under the heating temperature gradient is determined. Based on the stress-deformation law, the temperature parameters of the composite material thermal expansion molding during the manufacturing process of the composite material connecting rod mold are intelligently controlled.

8. The manufacturing control method of the automotive composite connecting rod mold based on thermal expansion molding according to claim 7 is characterized in that: The following steps are also included: Obtaining predetermined thermal expansion forming working conditions of the composite connecting rod mold under different preset connecting rod processing requirements, and constructing a connecting rod processing and forming system for the composite connecting rod mold according to the predetermined thermal expansion forming working conditions; Calculate the similarity between the target connecting rod processing requirements and different preset connecting rod processing requirements one by one, extract the connecting rod processing and forming system corresponding to the preset connecting rod processing requirement with the maximum similarity, and define it as the target connecting rod processing and forming system for the target connecting rod processing requirement; A finite element mechanical model of a steel connecting rod that meets the processing requirements of the target connecting rod is obtained based on a big data network, and the maximum stress value, maximum displacement deformation, and natural frequency of the steel connecting rod under different working conditions are extracted from the finite element mechanical model of the steel connecting rod using finite element calculation software; Determining, based on the maximum stress value, maximum displacement deformation, and natural frequency, baseline initial performance indicators that the composite material thermal expansion should follow when the composite material connecting rod mold meets the target connecting rod processing requirements; wherein the baseline initial performance indicators include structural strength, stiffness, and vibration characteristics; Obtaining the index threshold value specified for each benchmark initial performance index in the target connecting rod processing requirements, and constructing a standard composite connecting rod model according to the index threshold value specified for each benchmark initial performance index; By thermal expansion forming discrete combinations of composite materials with different resin matrix material types and fiber types, the simulated thermal expansion characteristic radar chart of each discrete combination of composite materials after simulated thermal expansion processing is fitted, and each simulated thermal expansion characteristic radar chart is compared with the thermal expansion characteristic radar chart of the standard composite connecting rod model for thermal expansion material selection analysis to obtain alternative composite material selection schemes.

9. The manufacturing control method of the automotive composite connecting rod mold based on thermal expansion molding according to claim 8, characterized in that: The method of thermal expansion forming discrete composite materials of different resin matrix material types and fiber types, fitting a simulated thermal expansion characteristic radar chart of each discrete composite material combination after simulated thermal expansion processing, and performing thermal expansion material selection analysis on each simulated thermal expansion characteristic radar chart and the thermal expansion characteristic radar chart of a standard composite connecting rod model to obtain an alternative composite material selection scheme specifically includes the following steps: Based on the big data network, the types of resin matrix materials and fibers that can be used to manufacture connecting rods in composite connecting rod molds are obtained. Based on the prepreg process flow, the types of resin matrix materials and fibers are discretely combined to obtain discrete combinations of composite materials that can be thermally expanded. Constructing a radar chart, performing a simulated thermal expansion process on each discrete combination of composite materials using a target connecting rod processing and forming system to obtain a thermal expansion characteristic index of each discrete combination of composite materials, and generating a simulated thermal expansion characteristic radar chart of each discrete combination of composite materials based on the radar chart thermal expansion characteristic index; Obtain an optimal thermal expansion characteristic radar map when conforming to a standard composite connecting rod model, align the optimal thermal expansion characteristic radar map with each simulated thermal expansion characteristic radar map, and calculate the radar area deviation between the simulated thermal expansion characteristic radar map and the optimal thermal expansion characteristic radar map one by one; If the radar area deviation is less than the preset radar area deviation, the discrete combination of composite materials corresponding to the simulated thermal expansion characteristic radar diagram under the radar area deviation is extracted and marked as an alternative composite material selection scheme; Upload all the extracted one or more groups of candidate composite material selection solutions to the manufacturing material selection terminal of the composite connecting rod mold.

10. The manufacturing control method of the automotive composite connecting rod mold based on thermal expansion molding according to claim 7, characterized in that: The following steps are also included: Acquiring actual temperature data of the composite material during a thermal expansion forming process and the distribution points of each actual temperature data, constructing a thermal map, and fitting and plotting each actual temperature data on the thermal map based on the distribution points to generate an actual temperature thermal distribution map of the composite material during the thermal expansion forming process; The Hamiltonian method is introduced. The Hamiltonian function is constructed by the Hamiltonian method on the actual temperature and thermal distribution diagram output by the finite element model of thermal expansion forming of composite materials. The Hamiltonian canonical equation is obtained. The Hamiltonian canonical equation is solved and the dynamic behavior description is performed to obtain the dynamic color gamut change distribution model of the actual temperature and thermal force. Obtaining a preset temperature control strategy for the composite material, and dividing the dynamic color gamut distribution change model of the actual temperature thermal force into M sub-model regions based on the preset temperature control strategy; The color gamut coding rules for temperature and thermal expression are obtained through a big data network. Based on the color gamut coding rules, the temperature and thermal color gamut change coding is read and written when a composite connecting rod mold is manufactured using the optimal thermal expansion characteristic radar chart as a benchmark. This generates a temperature and thermal color gamut distribution change query table. Obtaining a current color gamut distribution change code set for each sub-model region; if any current code in the current color gamut distribution change code set can be found in the color gamut distribution change query table, marking the sub-model region as a reasonable temperature control model region; If any current code in the current color gamut distribution change code set cannot be found in the color gamut distribution change query table, the sub-model area is marked as an unreasonable temperature control model area, and finally a model color gamut pattern diagram of the unreasonable temperature control model area is obtained; The heating rate, cooling rate and thermal expansion process parameters of composite material thermal expansion forming during the manufacturing process of composite material connecting rod mold are controlled based on the model color gamut pattern diagram.

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